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Primer The little things… …can make a difference. To improve protection and aesthetics of surfaces various coatings con...

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Primer

The little things… …can make a difference. To improve protection and aesthetics of surfaces various coatings contain nanomaterials. The impact of nanoparticles on human health and the environment is currently under discussion. Due to concerns over the possible health hazards of nanoparticles Aline Rommert and her co-authors of the German Paint Industry Association developed a test method to quantify the release of nanoparticles into the air caused by mechanical wear. The results show the amount of particles released depends on the coating applied and the substrate material used. No significant differences were observed between similar coatings with and without nanoparticles (page 29). Specifically developed waterborne acrylic polyols to formulate hand-applied two-pack varnishes and paints with good aesthetic and physical properties can make a difference as well. So far waterborne 2-pack polyurethane coatings offer excellent performance, but are generally only suitable for spray application. Adriaan Sanderse, Nuplex Resins BV, and his co-authors demonstrate that these methods of application open up many new end uses such as for instance highly durable clear and pigmented exterior wood coatings (page 16).

Damir Gagro

www.european-coatings.com

02 l 2011

European Coatings J OURNAL

Source: Filipebvarela - Fotolia.com

02 | 11

BC_A

Market Watch Industry news

 Divestment

Interview Pigments

“Upward trend to smoothen”

Fabiana Requeijo, Nubiola Group As demand for pigments has increased, pigment producer Nubiola has recently expanded its production capacities. According to Fabiana Requeijo, Global Market Manager – Coatings at Nubiola, the upward trend will remain, though it will smoothen. To strengthen its position and setting itself apart from the competition in Asia, the Spanish company focuses on eco-friendly products. _You have recently increased production capacities at your sites in Spain and Colombia. How do you expect the pigment market to develop? Fabiana Requeijo: We at Nubiola experienced a strong increase in the demand of our iron oxides and ultramarine pigments. The expansion of our production capacities was our answer to the growing demand. We expect to continue growing in the coming months though at a more moderate pace. As the market penetration of our several product lines is different, we see growth opportunities in all regions. However the areas with the strongest potential are Latin America and the AsianPacific region. _What pigments are currently mostly demanded? To what extent do you expect a change? Fabiana Requeijo: Our sales of iron oxides have followed an impressive upward trend and the results of our activated corrosion inhibitors are beating records. Al-

Source: b_sonders - Fotolia.com

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02 l 2011

though for niche applications, the most demanded pigment from Nubiola is ultramarine blue. As mentioned before, we expect this upward trend to smoothen in the following months. _How do you rate the competition situation in Europe and globally? Fabiana Requeijo: Our competitors are very big companies with a strong position in the market and a powerful brand. We at Nubiola are focused on high added value applications such as iron oxides for coatings and plastics, activated corrosion inhibitors or zinc ferrites. Due to our medium size we are more flexible and closer to our customers. This positioning also allows us to offer a higher added value than the increasing Asian competition. _Legislative regulations keep challenging the markets. To what extent will the market for pigments change? Fabiana Requeijo: Pigment producers are looking for more eco-friendly products to offer to their customers. We at Nubiola are not only focused on the research and development of more ecosustainable products such as zinc free corrosion inhibitors but also on the improvement of our industrial processes from a productivity and hygiene, quality and environment point of view. _On what further projects will Nubiola concentrate? Fabiana Requeijo: We at Nubiola invest approximately 2.5 % of our annual sales in R&D, which is one of our strengths. Our research activities are focused on iron oxides, corrosion inhibitors and ultramarine pigments. Process optimization is also one of our priorities to explore more efficient ways to produce pigments and ensure their quality and consistency. (gag)

Ashland to sell business unit to Perstorp Sweden-based company Perstorp has, through its subsidiary Perstorp Polyols Inc., signed an agreement with Hercules Incorporated, a subsidiary of specialty chemicals company Ashland Inc., for the acquisition of its Penta business, related technology and certain assets. It does not include the manufacturing plant in Louisiana, Mo., any real estate or employees. The transaction is fully in line with the companies’ strategies going forward and is part of an ambitious investment campaign to increase Polyol production. Ashland said the transaction is part of its strategy to focus on core specialty chemicals product areas. Pentaerythritol (PE) is a building block for the manufacture of alkyd resins, varnishes, PVC stabilizers, olefin antioxidants and other products. The acquisition is subject to fulfillment of certain conditions and is expected to be completed within 60 days. www.ashland.com

 Co-operation Sachtleben and Krahn expand partnership

Source: Sachtleben Chemie GmbH

In the context of the optimization of its marketing network for the paints and coatings industry, Sachtleben Chemie GmbH is entrusting distribution of its titanium dioxide and zinc/barium white pigments, fillers/ extenders and additives to distributor Krahn Chemie GmbH, based in Hamburg/Germany. The two companies have already practiced cooperation in the field of titanium dioxide pigments for a number of years. Since the beginning of this year, Krahn Chemie has been also responsible for marketing of barium sulfates, zinc sulfides and “Lithopone” throughout Germany and Austria. These products are used in the most diverse range of coatings applications. www.sachtleben.de


Market Watch Industry news

 Printing inks

Market studies

Siegwerk Scandinavia partners with RR Print

Acrylic resins 

Global market to grow by 2015 The global market for acrylic resins is forecast to exceed 16.4 billion pounds by the year 2015. Factors encouraging market growth include increased demand for superior-performing and costeffective products, and higher demand in developing markets such as Asia-Pacific, according Global Industry Analysts Inc. recently released global report on the acrylic resins markets. In addition, a growing number of new product introductions and rising demand for ecofriendly products are expected to impact market growth. The paints and coatings sector constitutes the largest end-use of acrylic resins. Acrylic-based paints and coatings

deliver improved color stability, flexibility, weatherability, and enhanced solid content and finishes. Consumption of acrylic resins by end-use markets is projected to exceed 4.4 billion pounds by 2012. Europe represents the largest regional market for acrylic resins worldwide, as stated by the new market research report. In terms of growth, Asia-Pacific is expected to register the fastest growth for acrylic resins. The region is forecast to have a CAGR of more than three percent over the period 2007 through 2015. The United States represents another major market for acrylic resins. www.strategyr.com

 Automotive coatings Silver tops ranking worldwide DuPont has issued its 58th Global Automotive Color Popularity Report, which lists silver and black in tight competition for the title of “world’s most popular car colour.” Only two percentage points separate silver from black as the leading vehicle color globally, and black’s popu-

larity in key automotive markets outside of North America is substantial. The top 3 global vehicle colors are silver (26 %), black/black effect (24 %) and white/ white pearl and gray (each 16 %). Black/black effect lead overall in Europe —across nearly all vehicle categories— with 24 % popularity. Gray was 5 % points behind with 19 %, and silver fell to 17 % percent popularity, according to DuPont’s 58th Global Automotive Color Popularity Report. The report includes automotive color popularity information and regional trends from 11 leading automotive regions of the world. Each year, the report reflects data from established and emerging growth markets in the automotive industry; and in 2010, for the first time, includes trends from South Africa. www2.dupont.com

According to DuPont’s latest automotive colour report, black tops ranking in Europe Source: DuPont

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02 l 2011

Siegwerk Scandinavia and RR Print in Denmark have recently started cooperation. RR Print is an agent and represents a number of international manufacturers of consumables and technical equipment for the graphic industry operating mainly in Scandinavia. One reason for the cooperation is the increasing demand for low-migration inks and coatings for food packaging. Magnus Remse, Manager of Siegwerk Scandinavia, says: “We will be especially active in the segment of special inks - such as our series of low-migration inks”. www.siegwerk.com

 Resins Kuraray invests to expand production facility in Europe Kuraray Co., Ltd., headquartered in Japan, has announced the expansion of PVA (polyvinyl alcohol) resin production facility at its wholly owned European subsidiary Kuraray Europe GmbH. The Japanese company invests approximately EUR 58 million to increase annual production capacity by 24,000 tons to 94,000 tons. PVB (polyvinyl butyral) resins made from PVA resins are used in various applications including paints, inks and binders. The planned commencement of operations is the first quarter of fiscal 2013. www.kuraray.eu

 Adhesives H.B. Fuller establishes local presence in Turkey Adhesives manufacturer H.B. Fuller Company has strengthened its foothold in Turkey by signing a definitive agreement to enter into a joint venture with Burak Özberk, its longstanding agent there. A new entity will be created, with H.B. Fuller owning majority control. “This agreement is a continuation of our commitment to invest in geographies that offer strong growth potential,” said Jim Owens, H.B. Fuller president and chief executive officer. The new company will provide a base for developing an even stronger local commercial team, local logistics support and the potential for local manufacturing in the future. www.hbfuller.com


Market Watch Company Portrait

Decorative coatings stand for 60 % of Dyo Coating’s turnover

Source: Dyo Coatings

"Increasing the share of international sales" Dyo Coatings aims at establishing an international brand

Miriam von Bardeleben Looking at its company history, Dyo Coatings is a true pioneer of the Turkish coatings-manufacturing industry. Turkey's first paint was produced by Yasar in 1941, and was followed by the opening of the country's first and at that time only coatings factory in 1953. Dyo's success story started with a merger in 2002: Yasas, Bayrakli and Akrilcompanies - under the management of Yasar Paint Group - were merged under the name of Dyo Paint Factories Industry and Trade SA. Today, Dyo Coatings ranks among the top two coatings suppliers in Turkey. Ahmet Yigitbasi, President Coatings, Yasar Holding A.S., explains in what way the coatings company has gone through restructuring recently and with which measures Dyo Coatings is aiming at extending the share of its international sales.

Ahmet Yigitbasi, President Coatings, Yasar Holding A.S.

10

_How is your portfolio structured? Ahmet Yigitbasi: With 60 % of the product portfolio of Dyo Coatings, decorative coatings has the largest share, while we generate 40 % of our sales with industrial coat-


02 l 2011

ings. In our two Turkish production sites in Gebze and Cigli (near Izmir) we produce construction coatings, industrial and furniture coatings, as well as polyester coatings and coatings for automotive and marine applications. Generally speaking,l we generate about 25 % of our turnover with high-end products, and 40-45 % with coatings in the medium segment. _What role does Dyo Coatings play in the Turkish construction coatings market? Yigitbasi: Among the four major manufacturers of construction coatings in Turkey, which together command a 75% market share, Dyo Boya ranks among the top two. In the construction coatings segment, there was an increase in the interior and synthetics groups in 2009, while sales in the exterior, wood, and other product groups paralleled those of the previous year. _What are the differences between the two Turkish sites? Yigitbasi: Solventborne coatings are only produced at the Cigli plant, whereas in Gebze all products are waterborne. At the Cigli site, which has a huge production capacity, Dyo Boya manufactures not only coatings but also alkyd resins.


Market Watch Company Portrait Occupying 67,000 m² of grounds, Dyo Boya’s Cigli plant is the largest in the Turkish coatings manufacturing industry. We are very happy to have an independent resins production at both Turkish sites. This integrated production makes us independent from standard products in the market. At Gebze, with a production capacity of 120,000 tpa, we occupy 65,000 m²of grounds. It is a modern factory with a high level of automation which produces coatings for the construction industry. _Which coatings systems do you manufacture at your production sites outside Turkey? Yigitbasi: At our Russian production site we produce decorative coatings and printing inks, in Eastern Europe, we focus on decorative coatings. In the Egyptian factory, we produce coatings for furniture and automotive applications. _In which markets do you aim at substantial growth in the year 2011? Yigitbasi: In 2009 91 % of Dyo Boya’s sales were made to the domestic market. The company’s exports in that year amounted to USD 15.1 million in value. The company’s principal export markets in 2009 were Egypt, Romania, Russia, and Azerbaijan. With our export activities we have not achieved our goal of establishing an international brand so far. But Dyo Boya is steadily increasing its presence in the international arena, especially through its activities in Egypt, Romania and Russia. The goal is to be one of the leading suppliers in these markets. We will aim at growing our business organically in neighboring countries. Especially for industrial paints, export is most important. Today we already export our products into 30 countries throughout Europe, but we want to proceed with these activities more focused in the future. _What are your goals for 2011? Yigitbasi: In 2011 and the years to come we want to participate more in growing markets in neighboring countries. During the last few years we have not actively tried to increase our sales outside Turkey, but rather been focused on our home market. In the past we used to present ourselves more technology-oriented, but 1.5 years ago we decided to switch to a new marketing approach: We have strengthened our marketing team, which today comprises 10 employees, and started to concentrate more on marketing issues. It goes without saying that additionally small investments for continuous improvements will be made at all sites. But we have not only worked on our marketing performance. Recently, Dyo Coatings has restructured its complete Human Resource and Sales organization, too. Thus, in the upcoming months we will mostly invest into marketing activities outside the Turkish market. We have set the goal to increase international sales to 13 % of our overall turnover in the year 2011. This is an increase of 3 % in comparison to the year 2009, when we had a turnover of USD 180 million with a 10 % share from international sales.

The Turkish company Dyo Coatings serves the market with 60,000 different colours

Facts about Yasar Holding and Dyo Coatings: Yasar Holding: Portfolio consists of 70 % food & beverages, 20 % coatings, 10 % other Yasar Coatings Group: 5 companies led by Dyo Coatings President: Ahmet Yigitbasi Turnover 2010: USD 260 million (2009: USD 180 million) Production sites in Turkey: Cigli (near Izmir) and Gebze Product segments: printing inks and coatings for architectural, industrial, furniture, automotive and marine applications Portfolio: 1,000 products, 60,000 different colours Turnover: 60 % decorative coatings, 40 % industrial coatings Brands: “Dyo” and “Dewilux” Staff: about 1000 employees Export to 40 countries, primarily in Central Asia, the Middle East, Europe, and Russia. Info: www.yasar.com.tr

The Turkish coatings market: Production volume: 750,000 t in 2010 (58 % decorative coatings), was 630,000 t in 2009 Market structure: Large to medium-sized companies account for 80 % of annual production volume, the remaining 20 % are small-scale manufacturers (mostly varnishes and thinners) Employees in the Turkish coatings market: 200,000 people in production and retail. Per capita consumption: 10 kg in 2010 (Europe: 14 kg)

The interview was conducted by Miriam von Bardeleben


02 l 2011


11

Associations CEPE

At the cross roads Nanotechnology: 2011 to bring crucial decisions

The year 2011 is going to be a very interesting year for the further development of smart coatings based on nanotechnology. Everybody seems to be interested in nanotechnology. Industries seek new applications for better products, consumers want more intelligent but completely safe products, NGOs want to save the world, and governments want to demonstrate their ability to protect workers, foster the economic growth, impeach critics and get reelected. Just some years ago nanotechnology was something for scientists, industry specialists and trade journalists presenting some obscure visions. 2011 will be the year when nanotechnology becomes a more or less normal part of our scientific, industrial and economic surrounding. Various organisations – from ISO and CEN, OECD, NGOs, industry associations and authorities – have their ideas, what nanotechnology should deal with. And the EU Commission has proposed the definition for nanoparticles or nanoobjects which would lead to a situation where almost everything is “nano”.

Clear definition problematic A definition that covers all nanomaterials whether they are of natural, incidental or manufactured origin, would mean that even certain biological systems – such as the lotus plant or turnip cabbage which show nanostructures on the surfaces of their leaves – fall under this definition. The same is true for incidents such as forest fires or other natural processes of decay and deterioration which happen to produce nanoparticles. The paint and printing ink industry in Europe would be very much affected by this definition. Every pigment may contain a more or less big amount of nanoparticles, emulsions are by nature containing some parts on the nanoscale and even products that are used for years and years maybe nanoproducts by definition. Furthermore the EU Commission suggest that internal or surfaces structures in one or more dimensions in the size range 1 Nanometer to 100 Nanometers should be a criterion for the definition of "nanomaterial". This would lead to a situation where all materials are defined as nanomaterials, because almost all materials have some internal structure at the nanometer scale. Moreover, when looking closely enough at surfaces, surface structures on the nanometer scale can be found on almost every object.

EU Commission came into force, this would mean one of the following: either everything is a nanomaterial, or immense resources will be needed to prove that something is not a nanomaterial. From a scientific point it is, however, not possible to provide concluding proof of a non-property. Therefore, the proposed definition does not define anything. But it is quite clear that the EU Commission will release some definition, probably as early as February 2011. And this will certainly influence various pieces of legislation and therefore regulate the use of nanomaterial in all those industries.

Kepping window of opportunity open The coatings industry in Europe has actively taken part in the development of nanotechnology from the very beginning. CEPE was involved on the European basis and many national associations participated in the national activities in risk research, consumer protection and workers protection or initiated own studies in these fields. The coatings industry always communicated openly and honestly about its activities and expectations of nanotechnology. The industry still is convinced, that nanotechnology and the use of certain nanomaterials will help make better products. Better products with respect to durability, environmental impact, effectiveness or aesthetics. And CEPE is working on behalf of the coatings industry to keep the window of opportunity open so that the benefits of the new technology may properly be realized in new, smart coatings. And 2011 will be a year that brings crucial decisions.

Regulation release expected soon Michael Bross, Chairman CEPE working group nanomaterials

12

The coatings industry in Europe proposes to use the term "nanomaterial" only for those nanomaterials which are intentionally manufactured and are used in the product on purpose. If a definition as broad as proposed by the


02 l 2011

Source: ag visuell - Fotolia.com


?

Expert Primer Voices

Waterborne coatings

Spoilt for choice Two alternatives to shift from solventborne technology As a known fact waterborne coatings have successfully substituted solventbornes in a variety of systems. Another eco-friendly alternative are high solid coatings. Both systems differ in their chemistry, as well as application and drying technology, and thus do not compete, according to Dr. Marie Bleuzen, Dow Coating Materials. It is up to the industry to decide which one to choose, as Taner Bicer, Karl Wörwag Lack- und Farbenfabrik GmbH & Co KG, points out.

“If we calculate the cost over the life time, waterborne pure acrylic coatings tend to be the most advantageous.”

1

Waterborne or high solids – mutually exclusive or possible one after the other?

2different What are the advantages of these technologies and where do

Dr. Marie Bleuzen Group Leader Architectural Coatings The Dow Chemical Company Valbonne, France [email protected]

you see their biggest potentials?

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!! European Coatings J OURNAL

Waterborne and solventborne high solids coatings are two alternative technologies to conventional solids solventborne alkyds to comply with the VOC directive. Waterborne coatings encompass different technologies such as alkyd emulsions, pure acrylics, styrene acrylics, combinations with PUD’s, etc., that each have different performance levels. I believe that high solids and waterborne technologies will stay mutually exclusive since they are very different from a formulation and application points of view. High solids are more difficult to formulate to obtain the desired rheology for optimal flow and leveling, without any sagging to obtain a nice defect free surface. This is very important for trim paints for instance which are usually brush applied. Also, their viscosity tends to be more sensitive to the temperature. Therfore high solids should be applied at a controlled temperature and obviously this is not always possible. Usually high solids are slower to dry than conventional solventborne alkyds which are also slower than waterbased paints which leads to low productivity.

02 l 2011

2

High solids are probably more aimed at the professional market since the painter must be quite skilled to perform a good job. Waterborne coatings are more user-friendly. Their lower odour and the ease of cleaning the tools with water are more appreciated by DIYers. Waterborne alkyds have a better environmental profile than solventbased ones but they still require driers for adequate drying, they yellow in the dark and their exterior durability is average. These issues will limit the growth of both. High solids do provide good hiding, high gloss and a nice finish when properly applied. They might be conomically more attractive than waterborne alternatives, at least if we take into account the initial paint and labour costs. However if we calculate the cost over the life time, waterborne pure acrylic coatings tend to be the most advantageous. The main advantage of waterborne acrylic is their environmental profile, furthermore they do not require driers, can be formulated at minimal VOC level, do not smell strongly, last long and do not yellow in the dark. I believe they are overall the most sustainable coatings, especially for exterior thanks to their longer durability.


Primer Voices Expert Waterborne coatings

“A changeover to high solid paint systems and the availability of comparable waterborne alternatives is rather unlikely.”

Taner Bicer Head R&D Decorative Liquid Paints Karl Wörwag Lack- und Farbenfabrik GmbH & Co KG Stuttgart, Germany [email protected]

1

Not for all applications or regions a clear “Yes” or “No” applies to answer this question. Due to continous increasing legal restrictions for the intention to reduce VOC, in Europe in particular, a high number of waterborne technologies are representing high state-of-the-Art. Paint technologies intended to be applied on automotive add-on parts for exterior and interior usage are indicative of such state-of-the-art paint technologies. Waterborne paints, such as primers, base coats or mono layer effect coats are utterly comparable to its solventborne counterparts. From a global standpoint, the current utilization of water- or solventborne technologies tend to balance each other out, however there are significant signs that the trend is being reversed from solventborne systems to be replaced by its waterborne alternatives within the next few years. A changeover to high-solid paint systems, and the availability of comparable waterborne alternatives preconditioned, is rather unlikely. A close look on the clear coat market for automotive industry reveals the picture is completely different. For alternative waterborne paint systems the acceptance did not meet the expectations for these applications. On a current status previsions do not show a clear picture of what will be preferred in the future, however high-solid clear coat technologies might be an option. In areas with major utilization of solventborne paint systems the crucial facts for changeover choices will be either costs (e.g. alterations of paint application lines) or performance (e.g. compliance to specifications) or both. Considering that, high-solid paint systems could be better options to some extent.


02 l 2010

ECJ

2

One of the essential advantage, switching to high-solid paint systems, is the potential to retain with the existing paint application line without higher alteration costs, as well as general benefits of using solventborne technologies, which apply for high-solid paint systems also. Already lower surface tensions and the significantly lower evaporation enthalpy of organic solvents are advantageous over waterborne paint systems in general. Lower evaporation enthalpy in particular is of big importance during the curing phase considering process costs (e.g. stoving temperatures) and of film formation qualities. Furthermore not all waterborne raw materials show the same performances such as solventborne raw materials. Hydrolysis stability of polyesters could exemplify to such performance distinctions. Big potentials for high-solid-systems could be basically fulfilling functional specifications such as corrosion protection. The feasibility to achieve comparatively high film builds is another benefit for high-solid paint systems. For decorative demands, excellent waterborne technologies are already established on the market which could be preferred considering contemperanous discussions about VOC legislations.

“High Solid Binders” Mircea Manea www.europeancoatings.com/books

Source: Mad [email protected]

15

Technical Paper

Source: Ivi/Pixelio.com

Waterborne coatings

Rolling out the future Formulating high-performance water-based PU coatings for hand application

* Corresponding author: Adriaan Sanderse Nuplex Resins BV Adriaan.Sanderse@ NuplexResins.com

Adriaan Sanderse* Jan Goossen Jaap Akkerman Dirk Mestach Waterborne 2-pack polyurethane coatings offer excellent performance, but are generally only suitable for spray application. Waterborne acrylic polyols have now been developed specifically to formulate hand-applied two-pack varnishes and paints with good aesthetic and physical properties. These methods of application open up many new end uses for these environmentally-friendly coating systems.

P

rogress made in recent years in the design of waterborne acrylic polyols and polyisocyanates for 2-pack polyurethane coatings has enabled the coatings formulator to overcome the drawbacks associated with the first generation of waterborne polyurethanes. Consequently, waterborne 2-pack (WB2K) technology has gained a strong foothold in the industrial coatings

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market, meeting all of the requirements for a true alternative to solventborne coatings. In addition to offering reduced emissions of volatile organic compounds (VOCs) during coating application, thus reducing the exposure of the painter to organic vapours, these coatings reduce the risk of fire and are easier to clean up (creating less hazardous waste to dispose of). Most WB2K coatings have been optimised for application by spraying, whether by compressed air, airless or electrostatic systems. So far, not much work has been done to develop formulation guidelines for WB2K systems that can be hand-applied by roller or brush. However, if it were possible to apply WB2K systems by hand with final aesthetic and film properties equivalent to those of spray-applied versions, this would open up a number of new end-use applications where properties such as high durability and excellent resistance properties are of prime importance. Typical examples of these enduse applications are highly durable clear and pigmented exterior wood coatings, yacht coatings, site-applied floor coatings and coatings to repair or refinish interior wood.


Technical Paper Waterborne polyurethanes Waterborne two-component PU technology summarised As for all paint formulation work, the right selection of the base resin components is crucial to obtain a satisfactory end result. In a WB2K coating system for hand application, component A is a polyol binder, consisting of small colloidal polyol particles suspended in water. Because of the fact that most waterborne acrylic polyols cannot emulsify hydrophobic isocyanates sufficiently to achieve proper homogeneous film formation [1, 2] component B is preferably a water-dispersible polyisocyanate hardener. Water-dispersible hydrophilic polyisocyanates can be prepared by reacting isocyanate trimers with monofunctional polyethers [2]. Most suitable polyisocyanate hardeners for this application are based on hexamethylene diisocyanate (HDI) trimers. However, in order to optimise properties such as hardness development, water dispersible polyisocyanates based on isophorone diisocyanate (IPDI) trimers can be used in combination with HDI types. Just before application, the polyol component is mixed with the polyisocyanate hardener. After application to the substrate, the coating cures through the hydroxylisocyanate reaction resulting in the formation of urethane crosslinks. In waterborne systems an important side-reaction occurs when isocyanate reacts with water. Some of the polyisocyanate groups are sacrificed in this reaction, forming the unstable carbamic acid which immediately decomposes and releases CO2 gas and a primary amine. The amine can then react with the isocyanate forming polyurea.

Results at a glance Waterborne 2-pack polyurethane coatings have been developed to offer performance that rivals that of solventborne versions. However, problems with flowout, defoaming and creation of CO2 during curing have until now made these coatings suitable only for spray application.

Table 1: Properties of new polyol for hand-applied waterborne 2K finishes Property

Value

Hydroxyl value

4.2 % OH

Solids content

47 %

pH

8

Acid value (on solids)

16 mg KOH/ g (mixed carboxylic and sulfonic)

Particle size

ca. 100 nm

Cosolvent

Butyl glycol (approx. 2 %)

Because of the water side-reaction, the NCO:OH ratio will have a significant impact on the coating properties: dry times, sanding, pot life, hardness development and chemical resistance. The competition between urethane versus urea reactions is governed by a number of parameters such as the surface area/particle size of the polyisocyanate emulsion, the emulsion stabilisation mechanism [3], neutralising agents and the time between mixing components A and B and the application of the coating. Publications by Urban et al. [4, 5] discuss in great detail the mechanisms and the influence of the ratio between hydrophobic/hydrophilic isocyanates and the curing conditions such as relative humidity on film-properties.

Binder modification minimises reaction with water Most waterborne polyol emulsions are stabilised by either anionic or non-ionic stabilising groups or a combination of both types. Anionic groups are required for fine particle size emulsions. Generally there is a relationship between the acid value of the polyol and the particle size of the emulsion. Most commonly the anionic groups are introduced by copolymerisation with carboxylic acid functional (meth) acrylic monomers such as acrylic or methacrylic acid. The

Waterborne acrylic polyols having mixed carboxylic and sulfonic stabilisation were developed to formulate hand-applied two pack varnishes and paint that show good aesthetic properties (gloss, flow and levelling). Proper selection of the thickener and defoamer are essential to obtain a good appearance. Evaluation of drying time, hardness build-up and resistance properties show that these can attain the same level as conventional solventborne polyurethane coatings. These products open up a wide new range of enduse applications for environmentally friendly high performance coatings where previously only high VOC systems were a viable option.


Figure 1: Flow curves of solventborne and waterborne 2K paints show marked differences

02 l 2011

European Coatings Congress 28.-30.03.2011 Nuremberg, Germany www.europeancoatings-show.com


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Technical Paper Waterborne polyurethanes carboxylic acid groups are converted into the salts using a volatile amine before or during emulsification in water. The problem associated with the presence of amines in the coating system is their catalytic action upon the isocyanate-water reaction. In order to decouple the emulsion particle size from the undesirable catalytic influence of the neutralising amine, the resin chemists at Nuplex Resins developed a proprietary technology to replace part of the carboxylic acid groups in the polyol by sulfonate-functional groups. The advantage of the sulfonate functionality is that these acid groups are neutralised with an inorganic base that has no unfavourable catalytic action. As a result the curing of the WB2K coating becomes more controllable and the flow and levelling properties are positively influenced. Additionally, the risk of CO2 bubbles becoming trapped in the drying coating is reduced. Table 1 shows the main properties of the waterborne acrylic polyol used in this study.

Figure 2: Changes in rheology during the pot-life of WB and SB 2K formulations

Rheology is adjusted with thickener and cosolvents

Figure 3: Timedependent flow curves of the modified WB2K formulations Table 2: Formulations of clear and white waterborne 2K coatings Component Millbase

Base

Hardener

Diluents

Properties

Raw material

Weight Clear varnish

White paint

Titanium dioxide

--

20.12

Pigment dispersant

–

1.03

Thickener

--

0.16

Demineralised water

--

5.8

Millbase total

--

27.11

Polyol emulsion

51.41

36.37

Wetting additives

0.52

0.36

High shear thickener

2.70

1.91

Defoamer

variable

variable

Demineralised water

13.73

11.86

HDI/IPDI based hydrophilic isocyanate

9.85

6.97

HDI based hydrophilic isocyanate

8.66

6.12

Cosolvents*

5.82

4.12

Demineralised water

7.31

5.18

Total

100

100

Density (kg/l)

1.04

1.22

Volume solids (%)

38.9

38.9

Weight solids (%)

42.3

50.5

VOC ready to use (g/l)

87

73

NCO/OH ratio

1.25

1.25

* Cosolvent mixture consisting of butyl acetate:dipropylene glycol dimethyl ether:butyldiglycol acetate in a ratio of 13/74/13

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The paint rheology is one of the most important parameters for brush or roller application. When comparing the flow curve of a conventional solventborne 2K paint formulated for hand application (VOC of about 500 g/l) with that of a WB2K system, the initial flow curves immediately after mixing are quite different (Figure 1). The flow curves also change in a different way as a function of the time after mixing (see Figure 2). At high shear the viscosity of WB2K paint is much lower, resulting in an initial brush resistance that is far too low. Additionally, the viscosity decreases during the pot life, so the application properties become worse after mixing of the paint. On the other hand, under low shear, the viscosity is much higher, with relatively poor flow as a consequence. Because of this rheological behaviour, defoaming of the paint after application also becomes difficult. In order to adjust the rheological properties of the WB2K paint a high shear polyurethane thickener is used to increase the ICI cone and plate viscosity to a level of 1.6 Poise, similar to that of the solventborne paint. Adding the thickener allowed the solids content of the paint to be lowered in order to reduce the low shear viscosity. This results in adequate brush resistance in combination with acceptable levelling, flow and defoaming properties. Most waterborne two-pack systems still require the use of some cosolvent, and its influence on the rheological profile needs to be taken into account. With this specific polyol it was found that a mixture of butyl acetate, dipropylene glycol dimethyl ether and butyldiglycol acetate offered the best balance between gloss and levelling. The flow curves as function of time after mixing for the adjusted formulation are given in Figure 3. A basic formulation for a hand-applied WB2K formulation (both pigmented and clear) is given in Table 2. The white millbase used in the pigmented formulation was prepared by dispersing in a pearl mill until a Hegmann fineness of less than 10 µm was obtained.


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Technical Paper Waterborne polyurethanes Table 3: Results for the foam test in a clear varnish (low addition = 0.17 wt%, high = 0.34 wt%) Defoamer

Addition level

Before

After

Orange peel

Clarity on glass

Gloss* (20 °)

Haze*

None

none

2

1

none

OK

84

24

Mixture of hydrophobic solids and polysiloxanes

low

5

5

yes

N/OK

76

93

high

5

5

yes

N/OK

82

39

Mixture of polymers and hydrophobic solids

low

4

4

none

OK

84

20

high

5

4.5

none

OK

83

28

Polyether siloxane copolymer

low

5

5

slight

OK

84

22

high

5

5

yes

OK

84

24

* Applied by brush 5 = best, 1 = worst

Table 4: Testing of optimised clear varnish and white paint Test procedure Persoz hardness (s) BK drying (min)

Clear varnish

White paint

1 day

107

105

7 days

284

234

phase I

15

15

phase II

195

210

phase III

360

270

phase IV

570

810

MEK resistance

double rubs

68

57

Household chemical resistance (DIN 68861-1A)

Exposure time

Ammonia (25 %)

16 h

3

5

Ammonia (25 %)

2m

5

5

50 % ethanol

16 h

5

5

Red wine

16 h

5

2

Coffee

16 h

5

3

Water

16 h

5

5

Acetone

16 h

5

5

Olive oil

16 h

5

5

Mustard

16 h

5

3

Black ink

16 h

5

3

Cleaning solution

16 h

5

3

5 = no visual damage, 0 = severe damage

"Polyurethanes" Ulrich Meier-Westhuis www.european-coatings.com/books

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Defoamer selection is another critical parameter During this work it was found that proper selection of the high shear thickener and defoamer is essential to formulate a paint with a good balance of aesthetic and performance properties. When formulating without a defoamer, the paint will contain a lot of foam after brush or roller application. After the paint has dried, this will result in surface defects such as pinholes and foam. The selection of a defoamer is not straightforward, however, as it should ensure proper defoaming during application without affecting gloss, flow and levelling. Preferably the defoamer should be easily introduced into the base without excessive shear. In the base for the clear varnish formulation given in Table 2, a number of different defoamer types were added at different concentration levels. All varnish samples were subjected to a foam test carried out as follows: the coating is applied with a pipette to the white part of a black-white paper contrast chart. After that, coating is applied to half of the black part of the chart using a brush. The varnish on the white chart is stippled intensively with the brush to incorporate a lot of air. This varnish is then brushed over the second half of the black part of the chart. The amount of foam in the two black parts of the chart is judged after drying overnight according to a scale of one (bad) to five (good). The clarity of the varnish applied onto glass was also judged after drying. The results are given in Table 3. In the foaming test the defoamers based on a mixture of hydrophobic solids and polysiloxanes and the polyether siloxane type performed well at both high and low addition levels. However, the first type introduced a strong orange peel effect in the dried film, even at low concentrations. This defoamer also adversely affected the clarity of the film. The polyether siloxane also introduced a slight orange peel effect, but at low concentrations this was judged to be acceptable. The defoamer based on the mixture of polymers and hydrophobic solids was somewhat less effective but had no effect on gloss and haze. At the lower addition level, no adverse effect on the levelling properties was observed. In order to verify whether these defoamers also worked in pigmented systems, additional tests were performed using the defoamers at the lowest addition level. Gloss and haze values were measured for both brush and roller application and are given in Figure 4. Based on these results a final selection was made of the defoamer based on the polyether siloxane copolymer.

Good resistance properties are obtained Additional tests were then performed on the final clear varnish and white paint formulations. The coatings were applied on glass panels at a wet film thickness of 120 µm and dried at 22 °C and 50 % relative humidity: drying and hardness development were measured. Household chemical resistance according to the DIN 68861-1A test (two coats of 175 and 125 µm wet film


Technical Paper Waterborne polyurethanes thickness respectively) on oak veneered panels and resistance against methyl ethyl ketone (MEK) were measured after 1 week of drying. Results are given in Table 4. It can be seen that a good overall level of resistance properties was obtained, thus producing coatings that offer a useful alternative to solventborne materials in a range of new application areas.

REFERENCES [1] Melchiors M. et al, Aqueous two-component polyurethane (2CPUR) coatings: an evolving technology, International Waterborne, High Solids and Powder Coatings Symposium, New Orleans, LA, February 10 1999. [2] Hombach R., Reiff H., Dollhausen M., US 4 663 377, May 1987, (assigned to Bayer AG). [3] Akkerman J. et al, sixth Nürnberg Conference, 2001, pp 17ff. [4] Otts D., Urban M., Polymer, 2005, Vol 46, pp 2699ff. [5] Otts D. et al, Polymer, 2005, Vol 46, pp 4600ff.

Figure 4: Gloss and haze values obtained with different types of defoamer

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13.01.11 15:45

Technical Paper Smart coatings

Development of a new underwater adhesive Released on demand * Corresponding author: Dr. Mark Geoghegan University of Sheffield T +44 114 222 3544 mark.geoghegan@ sheffield.ac.uk

Rita La Spina 1 Arnaud Chiche 2 Michael R. Tomlinson 1 Mark Geoghegan 1 * Adhesives which can be disbonded under specific conditions have many potential applications. An adhesive system was examined which consists of two polymers with different pH-dependent behaviour. The effects of film thickness, film structure and variations in load on bond strength and ease of release (at low pH) were studied.

T

he creation of coatings with “smart” behaviour is an ac active area of current research [1, 2]. In a recent paper, the present authors showed that a waterbased adhesive system can be fully reversible (switchable) and may also be re-used. Switchable adhesion is an important technological goal because it has many possible applications. Dismantling and re-assembling structures is an obvious case. Similarly, recycling would benefit from a switchable adhesive technology, especially if metals no longer needed to be welded. The automotive industry is a useful case in point, with the European Union’s End-of-Life Vehicles directive being an example of legislation that is a key driver in technological innovation. The packaging industry is also an area where reversible adhesives would improve recycling procedures.

Figure 1: Behaviour of two different polymers in response to pH changes: poly(methacrylic acid) [top] becomes uncharged and hydrophobic in acid conditions, whereas poly[2(dimethyl amino) ethyl methacrylate] [bottom], gains a proton in acidic solution 1 Department of Physics and Astronomy, University of Sheffield 2 Lehrstuhl für Physikalische Chemie II, Universität Bayreuth

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Finally, the medical industry requires improvements in areas such as wound dressing, where improvements in patient comfort drive many innovations. Similarly, the use of pH to switch adhesive behaviour could have applications in areas such as robotic endoscopy; the stomach, for example, is highly acidic and would be a possible trigger for switchable behaviour. Even cancers are associated with pH changes, although this effect is very subtle.

Several polymer types could create switchable bonding Switchability is important, but if the adhesive required little use of organic solvents in its creation and its application was purely waterbased, then another environmentally-friendly aspect would be added to its list of benefits. Several different kinds of water-soluble polymers exhibit “smart” behaviour, generally either in response to changes in temperature or pH. Polymers are required because they undergo shape changes in response to an environmental trigger. For example, pH-responsive polymers (weak polyelectrolytes) will be charged at certain pH values and uncharged at others. The level of charging depends on the polymer and pH. A charged polymer will extend because of the coulombic repulsion along the chain (for one polymer) or from the osmotic pressure caused by the presence of counter-ions (for a denser system of polyelectrolytes) [3]. The case of two oppositely charged polyelectrolytes is a true switchable adhesive system. The example studied here is shown in Figure 1. A poly(methacrylic acid) (PMAA) gel loses its proton and becomes negatively charged in water or basic solutions, but in acidic solution [left in figure] it is uncharged and hydrophobic due to the methyl group on the polymer. A poly[2-(dimethyl amino)ethyl methacrylate] (PDMAEMA) film retains a positive charge in water, but gains a proton in acidic solution. Brought together, they adhere strongly, but when the pH becomes acid enough (pH < 2), the adhesion fails [4]. Because both are weak polyelectrolytes, the level of charge can be controlled via the pH. In acid (basic) conditions the polybase (polyacid) is charged (although not every monomer is charged). Thus, the charge on the polymers can be controlled by using a suitable acidic or alkaline medium. The pH at which the polymers switch from charged to uncharged is not only governed by their pK a (acid dissociation constant), but also by their density; dense systems cannot retain the charge level that can occur in dilute polyelectrolytes.


Intuitively, this switchable adhesion is satisfying; the shape transition causes the (electrostatic or hydrogen) bonds to fail at the interface; but a deeper understanding is currently lacking. For example, the film in the original work was a grafted polymer layer (known as a brush), but it is important to know whether this can be replaced by a hydrogel layer. In a hydrogel film, the polymer chains are crosslinked, so that they are connected with each other as well as with the surface through grafting points. Such a question is not purely academic, because brush layers (and the gel films described in the current work) are not easy to synthesise, although in principle gel coatings can be easily produced, making them much more practical. The question of the mechanism responsible for the adhesion is more of a scientific than an engineering problem, but is still interesting, because, for example, it could be relevant to a deeper understanding of biological systems, where charge is inherently important.

Synthesis of the polymers summarised

our

in

eXPertise

Your

in

Adhesives & seAlAnts

In these experiments the gel was made via a free radical polymerisation of methacrylic acid while the brushes were polymerised by atom transfer radical polymerisation (ATRP) of 2-(dimethyl amino)ethyl methacrylate (DMAEMA), both as described in previous work [4]. A similar chemistry is described in more detail for the synthesis of a poly[2-(diethyl amino) ethyl methacrylate] brush [5]. Briefly, a monolayer of (11-(2-bromo-2-methyl)propionyloxy)undecyl trichlorosilane is allowed to self-assemble on a silicon substrate. This acts as an initiator for the ATRP reaction, which takes place in a mixture of acetone, a small

Results at a glance Adhesives which can be disbonded at will under specified conditions have many potential applications ranging from medicine to the automotive industry. Two polymers were synthesised which have different pH-dependent behaviour. The pH-switchable adhesion between a surface coated with a polybase film and a polyacid gel was measured using a modified Johnson-Kendall-Roberts (JKR) experiment. Initial findings included establishing that thicker films provided greater adhesion, whereas little difference was observed between having a chemically crosslinked polybase gel covering the substrate and linear polybase molecules end-grafted and grown (polymerised) from the substrate. Adhesion was observed to be pressure-sensitive, with the ease of release (at very low pH) being affected by the maximum load previously applied.

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02 l 2011


23

Technical Paper Smart coatings 273 K and then left overnight at room temperature under agitation. The final product was precipitated and purified by crystallisation from n-hexane, dried in vacuum and then characterised by proton NMR in CDCl3 to confirm the success of the synthesis [7]. The synthesis of the random copolymer poly[(2-dimethyl amino)ethyl methacrylate-co-benzophenone methacrylate] was achieved in the same manner as the PDMAEMA, except that 0.0228 mol [(2-dimethyl amino)ethyl methacrylate and 0.7089 mmol BPMA were added to 2.0 ml acetone [7]. The other components were used in ratios consistent with the previous description [6].

How adhesion was measured

Figure 2: Experimental set-up, showing the test mass (mg) which loads the polyacid gel (red) and so increases its contact area with the (blue) substrate; the contact diameter 2a is measured (B denotes the buoyancy in the aqueous system)

amount of water, catalysts CuCl and CuBr2, and a ligand 2,2’-bipyridine. In this work, experiments are also described in which a crosslinked polybase film is grafted to an initiator-coated silicon substrate. Here ATRP was also used, but DMAEMA was copolymerised with benzophenone methacrylate, (BPMA) following an earlier demonstration [6]. BPMA is a photocrosslinker, which under exposure to UV light results in the formation of a hydrogel film chemically attached to the initiator-coated silicon surface. The thickness of the hydrogel film is comparable to that of the brush. The synthesis of the BPMA was performed by a method similar to that described in earlier work [6]. 4-hydroxybenzophenone (20 g) was dissolved with triethylamine (20 ml) in 200 ml dichloromethane. Methacryloyl chloride (11.7 ml) was added dropwise to this mixture at

A specially designed modified JKR (Johnson–Kendall– Roberts) set-up was used for these experiments [4, 8]. Measuring adhesion in aqueous systems is not simple, but a design was used that allows a straightforward determination of the work of adhesion from what is known as the JKR equation. Figure 2 shows the experimental set-up. Three hemispherical PMAA gel lenses are brought into contact with a PDMAEMA polybase-coated silicon surface, and stabilised by a glass microslide placed on top. This geometry allows an even distribution of load on the lens system. The contact diameter (2a) is first measured at zero applied load. A mass is placed upon the glass microslide, which puts pressure on the polyacid gel (red), increasing its contact area (πa 2) with the polybase (blue) coated substrate. (This is in an aqueous medium, so the buoyancy B needs to be accounted for.) The contact diameter 2a is measured with the load applied and removed, as well as during application. The addition of the mass increases the contact diameter, which is then recorded. After removal of the mass, the diameter is recorded again. If the contact diameter returns to its value before the mass was applied, no adhesion is reported in the system. Larger increases in the contact radius above its initial (pre-load) value are indicative of greater adhesion, as shown in Figure 3. Standard methods of measuring soft adhesion involve shining light through the sample and studying the contact from above [9]. This was difficult here due to lack

Figure 3: Images of a PMAA gel on a PDMAEMA brush surface under different loading conditions; the shadow formed by illuminating the sample at an angle makes the contact diameter easier to measure

24


02 l 2011


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Technical Paper Smart coatings corresponds to the application of the load (P1) and its subsequent decrease to the removal of the load. At pH 2.4 the contact diameter returns to its original value (a = 0.51 mm), which indicates no significant adhesion. For the other two pH values, a relatively strong adhesion is observed. The contact radius measured in such a manner relates directly to the work of adhesion, G, which is the static crack propagation energy, i.e. the energy required to separate the two surfaces through the JKR equation [10] shown here as Equation 1. (1)

Figure 4: Variation of contact diameter over time at different pH values. The increase in diameter corresponds to the application of the load (P1) and its subsequent decrease to the removal of the load

In this equation, R is the radius of curvature of the gel, K is the elastic constant of the system (essentially controlled by the modulus of the gel), and P the applied load. The elastic constant of the gel is pH-dependent; in this case, it is determined separately using the Hertz equation, PR = Ka3. The Hertz equation is the limit of the JKR equation with G = 0, which is obtained when the polybase brush is replaced by a clean silicon substrate, because any adhesion can be neglected in comparison to that of the brush, and K can be measured directly in situ for different pH. Data illustrating the calculation of the elastic constant of the gel for different pH are shown in Figure 5. A linear plot of PR as a function of a3 reveals the elastic constant from its gradient.

Adhesion energy may be measured in different ways

Figure 5: The JKR equation with G = 0 reduces to the Hertz equation, allowing a calculation of the modulus of the gel from the gradient of the line

of contrast, but an alternative method was devised [8] in which the contact region is illuminated from the side, greatly improving the image quality. Figure 3 shows images of a PMAA gel on a PDMAEMA brush surface in aqueous solution at pH 3.4. In (a) and (c) taken respectively before and after the load is applied, the gel only has to support the glass above it, P0. In (b), the total load is P1. These data show adhesion because af > ai, although both are less than al, the contact radius during the application of load. Here, ai = 0.51 mm, al = 0.79 mm, and af = 0.60 mm. Sample data are shown in Figure 4, where the variation of contact diameter as a function of time is charted for three different pH values. The increase in diameter

26


02 l 2011

It is worth noting that the work of adhesion discussed in this work is not the same as the “real-world” adhesion. The latter is the energy required to separate an adhesive interface, whereas the former is usually smaller because it accounts for energy that can be recovered. For example, the hydrogel will be stretched during its detachment from the substrate. Stretching costs energy, and this elastic deformation contributes to the (JKR) adhesion, but when viscoelastic (irreversible flow) or plastic (permanent) deformations occur, energy is lost that is non-recoverable. The real-world adhesion includes these complicating effects. The JKR result is useful because it represents energy for a model system geometry, which can be reproduced. A smooth elastic hemisphere in contact with a planar (silicon) surface satisfies these requirements. The real-world adhesion is helpful in that it accounts for non-recoverable energy costs, but it cannot be expected to be the same as other examples of adhesion between the same materials, and so is a less useful parameter to characterise any particular adhesive system. The adhesion is known to increase with increasing load, which makes it pressure-sensitive [4]. The application of a load results in compressive and tensile stresses at the contact line of the gel and the surface [11]. The tensile stress is relevant in unloading; i.e. when the gel is pulled off the surface, but the compressive stress is important in both loading and unloading, and in any case domi-


Technical Paper Smart coatings nates the tensile stress. Nevertheless, the two are necessary because of hysteresis in the loading and unloading regimes. The stress is given by Equation 2. (2) Here, al and af are the radii of the contact line under the application of the load and after its removal respectively. The second term inside the brackets is the tensile term, which is independent of G.

How film thickness and structure affect adhesion Here, the adhesion of the gel to two different brush layers of the same grafting density (i.e. polymers per unit surface area) but different thickness (i.e. chain molecular mass) is considered. These two layers are 20 and 9 nm thick. The data in Figure 6 show that the thicker brushes exhibit greater adhesion than those of the thinner film. Neutron reflectometry data [4] suggest that the interaction between the gel and brush is at the interface between them, but the data in Figure 6 indicate that more bonding is occurring, which should be due to a greater number of amino groups in the brush available to contribute to the bonding. Any explanation for such an interaction must remain rather speculative at this point.

Figure 6: Work of adhesion for two different brush thicknesses as a function of stress (applied load); the thicker brush has stronger adhesion

Photo-crosslinked hydrogel films of 11 nm thickness were placed in contact with a PMAA hydrogel hemispherical lens and the adhesion was measured. As can be seen from a comparison with the system in which the polybase was end-grafted (Figure 7), there is no difference in adhesion between the two. This result provides the reassuring conclusion that the topology of the thin film does not affect the level of adhe-

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02 l 2011


27

Technical Paper Smart coatings

Figure 7: Work of adhesion is similar for a PMAA gel with PDMAEMA film either as a photocrosslinked layer or a brush layer

the switchability of the adhesion is unique. A system can only be environmentally switchable if adhesion is shown to fail under the relevant condition. There are reports of different energies of adhesion under different conditions, but this does not correspond to switching the adhesion fully off or on. True switchable adhesion requires a response to a stimulus applied in situ. The ease of detachment will be crucial to where the technology can be applied. Figure 8 shows the kinetics of gel release from a 20 nm PDMAEMA brush adhered at pH 3.4. The two peaks in the 62 mN data correspond to the addition of loads to bring the total load to 62 mN. When a load of 32 mN is applied [4], the adhesion fails when pH 1.1 has been reached, but for a 62 mN load the detachment is considerably slower. After several days, the gel was still attached to the substrate. It would be interesting to study whether further decreasing the pH would detach the gel or decrease the time required for separation. However, it is certainly true that increasing the pressure between the gel and brush increases the lifetime and durability of the bond, and this may be due simply to the greater contact area at larger pressures.

Results to date summarised The pH-dependent switchable adhesion of oppositely charged polyelectrolytes has been studied with a view to understanding whether the film thickness or the structural (rather than chemical) nature of the film itself affects the adhesion. Film thickness is an important parameter with a dramatic effect on the adhesion for a change of a factor of two, whereas it appears that the preparation method and configuration of the polybase film is less important. The adhesion is known to be pressure sensitive [4], and here it is shown that the switchable behaviour is also pressure sensitive, with larger loads separating after a considerably longer period of time, or requiring a more acidic solution in order to do so.

REFERENCES Figure 8: Kinetics of gel release from a 20 nm PDMAEMA brush adhered at pH 3.4; the system subjected to 32 mN equilibrates much more rapidly than that subjected to 62 mN

[1] Kumar A. et al, Prog. Polym. Sci., 2007, vol 32, pp1205ff. [2] Chen T. et al, Prog. Polym. Sci., 2010, Vol 35, pp 94ff. [3] Dobrynin A. V., Rubinstein M., Prog. Polym. Sci., 2005, Vol 30, pp 1049ff. [4] La Spina R. et al, Angew. Chem. Int. Ed., 2007, Vol 46, pp 6460ff. [5] Topham P. D. et al, Polym. Int., 2006, Vol 55, pp 808ff. [6] Huang J. et al, Langmuir, 2007, Vol 23, pp 241ff. [7] La Spina R., Switchable adhesion between oppositely charged

sion, which has important implications for the development of this technology. Scientifically, a hydrogel film has fewer and shorter “dangling ends” than the end-grafted polymer, and so has less scope to penetrate into the PMAA gel. Adhesion through entanglement is thus not responsible for any of the adhesion, at least for these smaller (9 nm) brushes.

Adhesion release varies with applied load The data shown in Figures 6 and 7 demonstrate the adhesion between oppositely charged polyelectrolytes, but

28


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polyelectrolytes, Ph.D. thesis, 2007, University of Sheffield, UK. [8] Ruiz-Pérez L., An experimental study of adhesion and conformational transitions in polyelectrolytes, Ph.D. thesis, 2006, University of Sheffield, UK. [9] Chaudhury M. K., Whitesides G. M., Langmuir, 1991, Vol 7, pp 1013ff. [10] Johnson K. L., Kendall K., Roberts A. D., Proc. R. Soc. London A, 1971, Vol 324, pp 301ff. [11] Silberzan P. et al, Langmuir, 1994, Vol 10, pp 2466ff.

ACKNOWLEDGEMENT The authors wish to acknowledge financial support from the European Community’s “Marie-Curie Actions” under contract MRTN-CT-2004-504052 [POLYFILM].


Technical Paper Nanotechnology

Danger in the air? Studying the release of nanoparticles from coatings in wear processes Manuel Vorbau Lars Hillemann Petra Fiala Michael Stintz1 Aline Rommert* Dietmar Eichstädt 2 Due to concern over the possible health hazards of nanoparticles, a study was made of the risk of free nanoparticles being released from coatings in wear processes. A standard abrasion test revealed that the nanoparticles remain embedded in the matrix material of the much larger (micrometre-sized) wear particles.

I

n various applications, surfaces are covered with different coatings, not only for aesthetic reason but also to improve scratch resistance, ultraviolet light resistance, thermal resistance or other 'defensive' properties. To achieve these effects in thin layers, modern surface coatings may contain an amount of 3 to 7 wt% nanoparticles. For this purpose, engineered nanoparticles (ENP) of metal oxides such as SiO2, ZnO or TiO2 are generally employed. The impact of nanoparticles on human health and the environment is currently under discussion. Producers of coatings, customers and end users seek information regarding the possible release of nanoparticles in daily wear on surface coatings. The German Paint Industry Association (VdL) therefore initiated scientific investigation of this topic. Nanoparticles are objects with all three dimensions in a size range from 1 nm to 100 nm (1 nm = one billionth of a metre). Numerous research projects (such as the European Nanosafe project) are examining the possible hazards to human health and the environment from nanoparticles. But there is still a lack of information about nanoparticle release due to defined treatment processes applied to surface coatings. The objective of this study was the characterisation of airborne particles which are released due to daily wear processes, such as walking on parquet floors. A test method based on a standardised abrasion device [1] was therefore developed.

by laboratory measurements. Investigations focused on particle release are essential for product safety for producers as well as customers. The following points are necessary to quantify and evaluate the particle release into air: » Surface coatings with and without ENPs have to be analysed and compared to quantify the influence of the ENPs. » Investigations have to be carried out under clean room conditions to avoid particle contamination from the environment. In contrast, the release of particles from surface coatings has to be assessed in relation to the ambient particle concentration in the environment.

* Corresponding author: Aline Rommert Verband der deutschen Lack- und Druckfarbenindustrie e.V. T +49 69 255 61 705 [email protected]

Three coatings tested for nanoparticle release As discussed above, surface coatings containing or not containing ENPs (zinc oxide particles, ZnO) were inves-

Basis for assessment of nanoparticle release Is it possible that the ENPs of modern surface coatings can separate from the matrix material during daily wear processes? This question can only be answered reliably TU Dresden 2 Verband der deutschen Lack- und Druckfarbenindustrie 1


Figure 1: TEM images of the ZnO nanoparticle additive and the TiO2 pigment particles as used in the architectural coating: (top) ZnO (bottom) TiO2

02 l 2011

"Nanotechnology" Stefan Sepeur www.europeancoatings.com/books


29


Figure 2: EDX analysis of TiO2 pigment particles and ZnO nanoparticle additives

tigated. Three suitable and representative coatings were chosen by the German Paint Industry Association: »»Furniture coating (two-pack polyurethane coating); »»Parquet coating (UV curable clearcoat); »»Architectural coating (white pigmented, waterbased acrylate). Images based on transmission electron microscopy (TEM) of the ZnO nanoparticles and the TiO2 pigment particles of the architectural coating are shown in Figure 1. The ZnO particles used have a broad size range

between 20 nm and 100 nm. In the coarse range, ZnO particles show a cylindrical shape, while finer particles are more spherical. The TiO2 pigment particles of the architectural coating, shown in Figure 1 (b), are larger than the ZnO particles. In addition to the particle morphology and their spatial arrangement in the matrix material, the chemical composition of the samples was analysed using energy dispersive X-ray spectroscopy (EDX) as shown in the example in Figure 2.

Standard abrasive tester simulates wear The test method developed allows the quantification of particles released through a defined abrasion process on surface coatings [2]. The abrasion device (“Taber Abraser model 5131”) shown in Figure 3 consists of two abra-

Figure 3: Functional parts of a “Taber Abraser”: (left) top view at abrasion wheels with sample (right) abrasion wheel on surface coating

Results at a glance Due to concern over the possible health hazards of nanoparticles, a test method was developed to quantify the release of nanoparticles into the air caused by mechanical wear of surface coatings containing them. In a simulated wear process, gravimetric analyses show reproducible abrasion of coatings was obtained by operating the “Taber Abraser”. The amount of particles released depends on the coating applied and the substrate material used. No significant differences were observed between similar coatings with and without nanoparticles.

Figure 4: Wear mass of the samples after 100 revolutions

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SEM and TEM images show that the nanoparticles are embedded in the matrix-material of the micrometre-sized wear particles. No significant concentrations of released nanoparticles could be detected as a result of the simulated daily wear process.


Technical Paper Nanotechnology sion wheels (in this case, type “CS-17” having corundum particles in a size range of 10-300 µm), which act on the sample surface. The wheels are moved by the rotation of the sample. Based on this principle of operation, the abrasion device simulates a wear process like walking with sandy shoes on surface coatings. Two particle analysers were applied for the characterisation of the abrasion-induced particle release. A Condensation Particle Counter (CPC) was used for the determination of the particle number concentration in a size range from 6 nm to 10 µm, while a Scanning Mobility Particle Sizer (SMPS) was employed to measure the particle size distribution between 16 nm and 626 nm. This configuration allows the quantification of both the total particle release and the released particles in the nanometre size range (< 100 nm). Similar measuring configurations were employed to characterise the mass concentration [3] and the release of nanoparticles from surfaces [4].

Figure 5: Particle size distribution of the 20 nm reference aerosol with a particle number concentration of about 700 cm-3

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02 l 2011


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Technical Paper Nanotechnology The following steps were performed for the investigations: »»Ensuring a particle-free environment in a laminar flow box »»Start of the particle measurement (CPC, SMPS) »»Start of the abrasion process (100 revolutions, normal force of 2.5 N) Based on the analysis of three samples for each type of surface coating, a total area of 0.9 m2 (30 cm2 abrasion area per revolution x 100 revolutions x 3 samples) was abraded during this study. In addition to the particle number concentration and the particle size distribution, the wear mass caused by the abrasion process was determined. Thus, a mass-specific particle release could be determined by the ratio of the number of particles released and the wear mass.

Particle counting can characterise nanoparticle levels Figure 6: Mean number of particles released with minimum and maximum deviations

Figure 7: Mean mass-specific particle release

The mean wear mass of the samples analysed is given in Figure 4. The results show that the abrasive wear processes are reproducible on surface coatings. Furthermore, the wear mass depends on the surface coating and the substrate material used. To verify the sensitivity of this experimental set-up to nanoparticles, a 20 nm reference aerosol was generated and directly injected into the sampling zone of the abrading device. SMPS measurements of the particle size distributions, given in Figure 5, confirm the functionality of the method. The wear mass of the surface coatings does not correlate to the release of nanoparticles, due to their negligible weight. For example, a spherical ZnO particle with a diameter of 20 nm and a density of 5610 kg/m3 weights 2.35 x 10-11 μg, while the mass of even a 200 nm ZnO particle amounts to 2.35 x 10-8 μg. In the presence of coarse particles, it is simply not possible to weigh a comparable number of fine particles. Therefore, particle counting systems were used in this study, because they are sensitive to small quantities of fine particles. The abrasion-induced particle number concentrations within the size classes were below the SMPS detection limit of 3 cm-3 at the operating conditions used. Consequently, only the total number of released particles measured by the CPC could be evaluated (see Figure 6). The measured numbers of released particles show that the particle release depends on the surface coating applied and the substrate material used. There is no significant difference in the particles released between the surface coatings with or without ENPs. Dividing the measured number of particles released (Figure 6) by the measured wear mass (Figure 5) results in a mass-specific particle release as shown in Figure 7. Differences are the consequence of different particle size distributions of the abraded particles.

Microscopy confirms no free nanoparticles released Figure 8: Images of scratches on a surface coating (left) caused by the sharp-edged abrasive particles (right) of the CS-17 abrasion wheel during the abrasion process

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Abrasion processes on surface coatings lead to the release of coarse and fine wear particles in process-related concentrations. Light microscopy (LM) and scanning elec-



Figure 9: SEM images of the furniture coating analysed: (left) broken edge at 5000:1; (centre) sample surface at 500 000:1; (right) ZnO additive at 100 000:1

tron microscopy (SEM) are the preferred techniques to analyse the compounds of the wear particles. Coarse scratches and grooves based on the abrasion process were analysed for their size with LM, as in the example shown in Figure 8a. Process-related wear particles are in the micrometre size range. LM cannot be used for the identification of nanoparticles, which may be located at the sample surface. The sharp-edged abrasive particles of the “CS-17” abrasion wheels shown in Figure 8b are partially mixed with the wear particles. Due to their shape and size they can be distinguished from the wear particles of the surface coatings. The size of the abrasive particles exceeds the upper limits of the measurement devices employed. SEM images provide detailed information of the surface morphology, as well as particle size and spatial arrangement of the ENPs on the surface coating as shown in Figure 9. TEM-images were used in this study to search for ENPs potentially released from the matrix material of the analysed surface coatings. During the TEM investigation, no free ENPs were observed. TEM-images, like the one in Figure 10, show that the ZnO nanoparticles are still embedded in the matrix-material of the micrometre-sized wear particles.

Safety of nanoparticles in coatings is confirmed The results of the study can be summarised in a few observations. The particle release depends on the surface coating and the substrate material used, but the amount of particles released was below the detection limit of the SMPS system employed. The abraded mass of the surface coatings does not correlate to the release of nanoparticles due to their negligible weight. Number-based particle detectors are sensitive to ultrafine particles and provide information about the particle size distribution of the wear particles. SEM, TEM and EDX are useful for the characterisation of the particle morphology and species. There is no significant difference in the concentration of the particles released between the different surface coatings analysed with and without nanoparticles. Light microscopy confirms that the wear particles are in the micrometre size range. The nanoparticle additives are embedded in the matrix material of these wear particles.

REFERENCES [1] DIN 68861-2: Möbeloberflächen, Verhalten bei Abriebbeanspruchung. Deutsche Norm, Beuth Verlag, Berlin, 1981. [2] Vorbau, M., Hillemann, L., Stintz, M., Method for the characterization of the abrasion induced nanoparticle release into air from surface coatings, Journal of Aerosol Science, 2009, Vol 40, No 3, pp 209-217. [3] Hillemann, L., Stintz, M., Ripperger, S., Bestimmung der Massekonzentration von Aerosolen mit anzahlbewertenden Messverfahren, Chemie Ingenieur Technik, 2004, Vol 76, No 9, pp 1388-1389. [4] Hillemann, L., Kätzel, U., Stintz, M., Detection of nanoparticle releases from surfaces, VDI-Berichte, 2005, Vol 1920, pp 195-198.

ACKNOWLEDGEMENTS

Figure 10: TEM image of a wear particle with embedded ZnO nanoparticles

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The authors would like to thank the German Paint Industry Association (VdL) for financial support for the project. Additionally, the authors wish to thank Bayer Technology Services, Leverkusen, Germany for the TEM and EDX analysis and the Institut für Lacke und Farben e.V., Magdeburg, for the sample preparation.


Technical Paper Raw materials

New lightweight aggregates from building waste A new raw material for lightweight concrete

Petra Jakubcová* Dirk Adomat Peter Ramge Katrin. Rübner

1200 kg/m3 and represent an important proportion of the aggregates used in the construction sector.

Materials such as masonry rubble are potential raw materials for the production of lightweight aggregates for use in lightweight concretes. Their excellent technical charateristics makes them an attractive substitute for natural expanded clay granules. The lightweight concretes made from these new aggregates show similar properties to those made with conventional expanded clays.

Synthetic lightweight aggregates are made by thermal treatment of the raw materials, whereby the expansive process either originates in the chemical composition of the raw materials or has to be initiated by adding so called expanding agents. Natural materials, such as expandable clay, shale, perlite and slate, as well as industrial waste products, such as fly ash or blast furnace slag are typical raw materials. Recently, the use of other materials, such as waste glass or sewage sludge has been looked at [36]., Their use seems possible in the building industry and helps in the reduction of the general waste volume and constitutes sustainable material recycling. Every year between 50 and 60 million tonnes of construction rubble are produced in Germany alone. Only two-thirds of this is recycled at present, mostly in mining or in road construction and other low-grade applications. Less than 1 % of such waste is reused for high-grade building construction work [7]. The remaining third is just dumped. Although crushed concrete or bricks can be used in high-grade mineral building materials, fine grained construction waste is inappropriate for recycling, as it is very heterogeneous. Thus, the Federal Ministry of Education and Research is funding a research project, the aim of which is to increase efficiency in the construction sector by developing technologies to produce high-quality

C

oncrete containing lightweight aggregates has been known since ancient times. Natural aggregates of volcanic origin were used for construction purposes, for example in the Mayan pyramids in Mexico [1] or monumental structures in the Roman Empire, the most famous examples of which are the Colosseum and the Pantheon in Rome. The Romans used natural as well as artificial aggregates, such as pumice, crushed lava and crushed brick in parts of these buildings. Pumice is still used today in structural lightweight concrete [1]. With an increasing demand for lightweight aggregates and their limited availability as naturally occurring materials, techniques had to be developed for their manufacture. Large scale industrial production of lightweight aggregates started after WW1 [2]. Today, they are produced in a wide range of loose bulk densities from 100 to

Lightweigt agregates: State of the art

* Corresponding author: Dr. Petra Jakubcová, Federal Institute for Materials Research and Testing (BAM) [email protected]

Figure 1: Expanded granules made of masonry rubble (EG) in the grain size fractions 2-4 mm (left) and 4-8 mm (right)


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Technical Paper Raw materials How expanding agents work

Figure 2: Sorting analysis of the raw materials according to [11]

The project aims to develop a technology to produce high-quality lightweight granules with defined properties from recycled heterogeneous, fine grained mineral construction waste. To this end, fine grained construction waste is mixed and granulated; these so called “green” granules are then expanded and stabilized in a thermal process in a rotary kiln. A gas is released in the temperature range at which a partial melting process takes place. This is the basic condition for the expanding process. The quality of the final product depends on the correct adjustment of the gas release and the temperature-dependant consistency of the melting phase. In the case of natural expandable clays, the organic carbon content, often together with the presence of iron hydroxides, causes the expansion. The production of lightweight aggregates from non-expandable materials, for example expanded glass granules, requires the addition of an expanding agent. The amount and kind of this agent and the burning process are the main influences on the properties of the aggregates. A typical expanding agent is silicium carbide (SiC). When heated in the presence of caustic alkali and air, SiC converts into silicate and carbonate compounds, thus causing a carbonate gas to be released at a temperature range of 800 to 1500 °C [9]. The lightweight aggregates produced from fine-grained construction waste are used in lightweight concrete, as filling for thermal and acoustic insulation or in applications outside the building sector. The raw materials used in the work described here was masonry rubble from two different processing plants. In general, this material is heterogeneous. It is made up of, brick, mortar and plaster, but also materials, such as lightweight concrete, concrete, sand lime brick and

Results at a glance The masonry rubble tested is a suitable material for the production of lightweight aggregates. Expanded granules produced from masonry rubble have similar technical properties to commercial expanded clays. However, they show significantly lower water absorption.

Figure 3: Proportion of the main components of the investigated masonry rubble batches compared to the general composition of expandable clay materials according to Riley and Wilson

building aggregates from secondary raw materials based on heterogeneous construction and demolition wastes. This is part of the funding priority called "r² – Innovative technologies for resource efficiency - resource-intensive production processes" [8]. It is coordinated by the chair "Preparation of Building Materials and Recycling" (ABW) art the Bauhaus-Universität Weimar.

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The granules show a very low chloride and sulphate content, which is a crucial condition for the use as lightweight aggregate in concrete. Due to their environmental compatibility the granules produced from masonry rubble can substitute natural expanded clay granules also in other uses such as in fillings for thermal and acoustic insulations and application as planting substrates. Lightweight concrete produced with the new expanded granules shows similar technical properties to lightweight concrete containing conventional expanded clays.


Technical Paper Raw materials lightweight aggregates

grain size [mm]

water adsorption 24 h [%]

loose bulk density [kg/m3]

bulk density [kg/m3]

true density [kg/m3]

total porosity [%]

grain strength [MPa]

11.3

582

1081

2689

59.8

2.0

17.9

449

792

2636

70.0

3.0

EC 2

20.6

563

1004

2724

63.1

2.3

EG

11.1

612

1144

2693

57.5

3.0

15.5

592

1054

2667

60.5

5.2

22.2

590

1118

2731

59.1

3.2

EG EC 1

2-4

EC 1

4-8

EC 2

pH

ϭ

As

Pb

Cd

Crges

Cu

Ni

V

Zn

Cl-

SO42-

µs/cm

µg/l

µg/l

µg/l

µg/l

µg/l

µg/l

µg/l

µg/l

mg/l

mg/l

300

150

600

Limitvalue

12.5

3000

50

100

5

100

200

100

300

EG 2-4 mm

9.9

122.63

13.77

0.00

0.03

0.63

0.47

0.03

34.07

2.73

0.68

24.75

EG 4-8 mm

10.1

141.00

14.93

0.00

0.10

0.97

7.53

0.13

27.87

1.90

0.98

25.92

aerated concrete, can occur, depending on the original building that was demolished. Batches of masonry rubble with the following grain size ranges were used: 0-32 mm (batches MW 0 and MW 1), 0-8 mm (batch MW 2) and 8-32 mm (MW 3). MW 1, MW 2 and MW 3 came from one processing plant and MW 0 from another. The raw materials underwent a sorting analysis according to DIN 4226-100 [10] at the ABW [11]. Subsequently, their chemical composition was analysed according to DIN EN 1962 [12] at the BAM. Lightweight aggregates with a grain size of 2-8 mm were produced at the ABW [11]. The first samples used MW 0, the most critical batch, which had a low brick content. A loose bulk density below 800 kg/ m³ and a grain strength value exceeding 1.0 MPa were aimed at. The masonry rubble was crushed in an impact crusher and ground in a ball mill to a particle size below 100 µm. The resulting powder was mixed with water and the expanding agent (SiC) in a high shear mixer which allowed mixing and granulating in one step. The resulting green granules were expanded and stabilized in a thermal process by means of a rotary kiln. A SiC dosage of 3 % by mass and a temperature of about 1185 °C [13] gave the maximum expanding effect. The granules were analysed according to, DIN EN 1744-1 [14] and DIN 196-2 [12]. To assess the environmental compatibility, aqueous leachates of the granules were monitored for pollutants according to the DIBt guidelines [15]. The granules were separated into two grain size groups, 2-4 mm and 4-8 mm, as shown in Figure 1. Both fractions were tested for the following: grain strength (DIN EN 130551 [16]), loose bulk density (DIN EN 1097-3 [17]), bulk density and water absorption (DIN EN 1097-6 [18]), true density (DIN 66137-2 [19]) and total porosity (DIN 66 137-1 [20])..

Table 1: Material properties of the new expanded granules EG compared to the two conventional expanded clays EC1 and EC2

Table 2: The results of environmental compatibility analyses of the expanded granules EG according to [29]

paring lightweight concrete made with EG and samples made with two different conventional expanded clay granulates (EC1 and EC2). The mixtures were produced with ordinary Portland cement CEM I 32.5 R, at a water/ cement ratio of 0.50 and aggregates with a grading that fits the A/B 8 line according to DIN 1045-2 [21]. The sand fraction (0-2 mm) consisted of natural river sand, whereas for the fraction between 2 and 8 mm the lightweight aggregates EG, EC1 and EC2 were used, respectively. The properties of fresh and hardened concrete such as workability, compressive strength, dynamic and static modulus of elasticity, shrinkage behaviour and porosity, were measured on all three test concretes (LWAC-EG, LWAC-EC1

Comparision with other materials The suitability of these new expanded granules (EG) as lightweight aggregates was tested in concrete by com-


Figure 4: Development of shrinkage and compressive strength until the age of 28 and 56 days

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Technical Paper Raw materials Table 3: Properties of hardened concrete at the age of 28 days LWAC-EG

LWAC-EC 1

LWAC-EC 2

flexural strength [MPa]

4.8

4.6

4.8

compressive strength of prisms [MPa]

36.8

37.4

37.4

compressive strength of cubes [MPa]

35.6

32.8

33.3

static modulus of elasticity [MPa]

18000

17167

17500

dynamic modulus of elasticity [MPa]

21854

20637

21411

shrinkage [mm/m]

0.667

0.656

0.642

true density [kg/m³]

2570

2560

2600

bulk density [kg/m³]

1660

1620

1680

total porosity [%]

35.5

36.7

35.5

chemical composition is more uniform than expected from the results of the sorting analysis. All batches qualify for use in the production of lightweight aggregates, as their chemistry is similar to natural expandable clays. The yield for the targeted grain size fraction 2-8 mm exceeded 80 %. The expanded granules show similar technical characteristics to commercially available materials. Their loose bulk density is below 650 kg/m3, the total porosity around 60 % and grain strength above 2.0 MPa. Their water absorption within 24 hours is significantly lower than that of the conventional expanded clays EC1 and EC2 and an advantage for use in concrete. The pore structure and its influence on the material properties will be looked at in the future. The first qualitative impression indicates that granules produced from masonry rubble give larger pores. Table 1 shows the material properties compared to conventional expanded clays. As expected from the raw material analysis, the chloride and sulphate content of the expanded granules is below the limit of values for aggregates used in concrete. Table 2 shows the results of the environmental compatibility analysis. They are within the limits defined in the DIBt guidelines [14]. Both fractions of the granules qualify for use in structural lightweight concrete.

No significant differences observed

Figure 5: Fractured surfaces of concrete made with expanded granules produced of masonry rubble (a) and of concretes made with conventional expanded clay (b) and (c)

Two sessions on "Construction chemicals" at European Coatings CONGRESS www.europeancoatings-show.com

38

and LWAC-EC2) according to DIN EN 12350-5 [22], DIN EN 12390-7 [23], DIN 66137-1 [19], DIN EN 12390-4 [24] and the recommendations of DAfStb [25]. To this end, prismatic and cubic standard specimens of 40 mm x 40 mm x 160 mm and 100 mm x 100 mm x 100 mm size were produced. The strength-test samples were stored under water until testing. The shrinkage-behaviour samples were stored at 23 °C and 50 % relative humidity after demoulding and the samples for the determination of the modulus of elasticity were stored at 95 % relative humidity for seven days and subsequently at 50 % relative humidity. The flexural strength and the compressive strength were determined on the prismatic specimens at the age of 7, 28 and 56 days. The compressive strength of the cubic specimens was tested, according to DIN EN 206 [26], after ageing for 28 days. The composition of the raw materials can be seen in Figure 2. The results differ from batch to batch. However, for their use in the production of lightweight aggregates, the chemical composition must be known. The ternary diagram in Figure 3 compares the proportion of the three main components (SiO2, Al2O3 and flux) to the range of natural expandable clays according to Riley [27] and Wilson [28]. The term "flux" applies to CaO, MgO, Fe2O3, Na2O and K2O, which influence the melting process. Obviously, the raw materials’


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New lightweight aggregates produced from masonry rubble enable production of lightweight concrete with similar properties to those made with conventional expanded clay aggregates. None of the relevant concrete properties change significantly. Figure 4 compares the development of the compressive strength and shrinkage of the concretes containing the new expanded granules and the conventional expanded clay aggregates. No significant differences can be observed. All three lightweight concretes belong to strength class LC 25/28 according to DIN EN 206 [25]. Table 3 summarizes the properties of hardened concrete after 28 days. The results for modulus of elasticity, density and porosity confirm that there are no significant differences between the concretes containing the expanded granules produced from masonry rubble and those containing the conventional expanded clay aggregates. Figure 5 shows the fractured surfaces of specimens after the flexural strength test specimens. No segregation (i.e. floating of the lightweight aggregates) was seen in any samples. The focus of future studies will be the optimisation of the production process as well as the raw material processing in order to optimize the material properties of the granules. The potential of making tailor-made products, made by controlling the process parameters of the production and the raw material selection, which can adapt and optimise aggregates properties for certain applications is expected to be higher than with conventional expanded clays.

[1]

B y

E

References

A

Chandra S., Berntsso L., Lightweight aggregate concrete: science,

p

technology, and application, Noyes Publications, 2002 [2] Expanded Shale Clay and Slate Institute, “Lightweight ConcreteHistory, Applications economics” Booklet, 1971, USA.


C

Technical Paper Raw materials [3] Ducman V., Mladenovic A., Šuput J. S., Lightweight aggregate

[16] DIN EN 13055-1: Leichtzuschläge - Teil 1: Leichte Gesteinskörnungen

based on waste glass and its alkali-silica reactivity. Cement and Con-

für Beton, Mörtel und Einpressmörtel. Beuth Verlag, Berlin, August 2002

crete Research, 2002, 32, pp. 223-226

[17] DIN EN 1097-3: Prüfverfahren für mechanische und physikalische

[4] González-Corrochno B., Alonso-Azcárate J., Rodas M., Production

Eigenschaften von Gesteinskörnungen - Teil 3: Bestimmung von Schüt-

of lightweight aggregates from mining and industrial waste. Journal of

tdichte und Hohlraumgehalt. Beuth Verlag, Berlin Dezember 2005

Environmental Management, 2009, 90, pp. 2801-2812

[18] DIN EN 1097-6: Prüfverfahren für mechanische und physika-

[5] Wang X., Development of lightweight aggregate from dry sewage

lische Eigenschaften von Gesteinskörnungen - Teil 6: Bestimmung

sludge and coal ash. Waste management, 2009, 29, pp. 1330-1335

der Rohdichte und der Wasseraufnahme. Beuth Verlag, Berlin,

[6] Nanes R., Strength of Lightweight Glass Aggregate Concrete.

Dezember 2005

Journal of Materials in Civil Engineering, 2006, 18, pp. 710-714

[19] DIN 66137-2: Bestimmung der Dichte fester Stoffe - Teil 2: Gaspy-

[7] ARGE Kreislaufwirtschaftsträger Bau [Hrsg.], Monitoring-Berichte

knometrie. Beuth Verlag, Berlin, Dezember 2004

Bauabfälle 1 bis 5, Arbeitsgemeinschaft Kreislaufwirtschaftsträger Bau,

[20] DIN 66137-1: Bestimmung der Dichte fester Stoffe - Teil 1: Grundla-

Berlin, 1996 bis 2006

gen. Beuth Verlag Berlin, November 2003

[8] BMBF - Vorhaben „Aufbaukörnungen - Steigerung der Ressourcen-

[21] DIN 1045-2: Tragwerke aus Beton, Stahlbeton und Spannbeton -

effizienz im Bauwesen durch die Entwicklung innovativer Technologien

Teil 2: Beton - Festlegung, Eigenschaften, Herstellung und Konformität.

für die Herstellung hochwertiger Aufbaukörnungen aus sekundären

Beuth Verlag, Berlin, August 2008

Rohstoffen auf der Basis von heterogenen Bau- und Abbruchabfällen",

[22] DIN EN 12350-5: Prüfung von Frischbeton - Teil 5: Ausbreitmaß.

Verbundkoordinator: A. Müller, Bauhaus-Universität Weimar, Förder-

Beuth Verlag, Berlin, August 2009

kennzeichen 033R015D, 2009-2012

[23] DIN EN 12390-7: Prüfung von Festbeton - Teil 7: Dichte von Festbe-

[9] Römpp: Siliciumcarbid. RÖMPPOnline, Version 3.5, Georg Thieme

ton. Beuth Verlag, Berlin, Juli 2009

Verlag, Stuttgart, 2009

[24] DIN EN 12390-4: Prüfung von Festbeton - Teil 4: Bestimmung der

[10] DIN EN 4226-100: Gesteinskörnungen für Beton und Mörtel - Teil

Druckfestigkeit. Beuth Verlag, Berlin, Dezember 2000

100: Rezyklierte Gesteinskörnungen. Beuth Verlag, Berlin, Februar 2002

[25] Prüfung von Beton: Empfehlungen und Hinweise als Ergänzung zu

[11] Schnell A., Müller A., Entwicklung von Technologien zur Herstel-

DIN 1048, DAfStb, Heft 422, Beuth Verlag, Berlin 1999

lung von Leichtgranulaten aus heterogenen Bau- und Abbruchabfällen.

[26] DIN EN 206-1: Beton - Teil 1: Festlegung, Eigenschaften, Herstel-

In: Rohstoffeffizienz und Rohstoffinnovationen, Fraunhofer Verlag,

lung und Konformität. Beuth Verlag, Berlin, Juli 2001

Stuttgart, 2010, pp. 235-247

[27] Riley C., Relation of Chemical Properties to the Bloating of Clays.

[12] DIN EN 196-2: Prüfverfahren für Zement - Teil 2: Chemische Ana-

Journal of the American Ceramic Society, 1951, pp. 121-128

lyse von Zement. Beuth Verlag, Berlin, Mai 2005

[28] Wilson H., Lightweight Aggregates for the Construction Industry.

[13] Müller, A., Schnell A., Aufbaukörnungen. Zeitschrift BR für Baustoffre-

Journal of the Canadian Ceramic Society, 1953, 22, pp. 44-48

cycling, Abbruch, Entsorgung und Altlastensanierung, 2010, 26, pp. 22-25

[29] Rübner K., Herbst T., Jakubcová P., Sekundärrohstoffe zur

[14] DIN EN 1744-1: Prüfverfahren für chemische Eigenschaften von Gestein-

Betonherstellung - Eigenschaften und Eignungsbewertung.

skörnungen - Teil 1: Chemische Analyse. Beuth Verlag, Berlin, Mai 1998

Fachtagung Recycling R’10, Bauhaus-Universität Weimar, Fakulät

[15] Zulassungsgrundsätze für die Bewertung der Auswirkungen von

Bauingenieurwesen, Professur Aufbereitung von Baustoffen und

Bauprodukten auf Boden und Grundwasser, Teile 1-3, Deutsches Institut

Wiederverwertung, Weimar, 22.-23. September 2010, http://www.

für Bautechnik (DIBt), Mai 2009

abw-recycling.de

By the way, how do you find Clariant ? Easy. Visit us at the European Coatings Show 2011, 29-31 March, Hall 7, Booth 7-422. And discover how our colorants and additives add value to your end products in the

Exactly your chemistry.

paint and coatings industry. Welcome to the show, and, of course, welcome anytime at Clariant International Ltd, www.clariant.com


What do you need? 02 l 2011


39

Technical Paper Architectural coatings

Formulating sustainable architectural coatings Measuring sustainability and formulating with bio-renewable polymers

* Contact data: David C. Sykes Paint Research Association T:+44 208470842 [email protected]

David Sykes Life Cycle Analysis (LCA) studies of architectural coatings and recently published data on the carbon footprint of interior wall paints and trim paints are ways of measuring sustainability. Developments in bio-polymers may lead to truly sustainable paints, but there are difficulties in achieving a complete replacement of petrochemical-based raw materials.

S

ustainable development is usually defined in very broad terms. It concerns enabling future generations to meet their needs as well as the impact of economic, social, and environmental issues. Such broad generalisations need to be narrowed and quantified in order to be useful for product development in the coatings industry. It is important to consider the elements of sustainability which are controllable by formulating scientists and technicians. The focus here is the impact on the environment of our activities, in particular the development and selection of raw materials for coatings formulations. To be sustainable, paint ingredients should meet the basic criteria of minimising damage to the environment and, where possible, being based on renewable sources. In addition, for commercial reasons, the coating needs to possess acceptable performance and cost.

How to measure sustainability There are several methodologies available for measuring sustainability. The one thing they have in common is that they are all very complicated and therefore expensive and time-consuming. The complexity comes from the fact that they require a large amount of data, which is often not readily available to individual companies. The strategy for coping with this generally involves using a consultant to collect the data and applying some measures of simplification to focus on the items of major impact. So far there has been little co-operation within the paint industry to agree on criteria, pool information, share the costs and reach a consensus on data for model formulations. One methodology is Life Cycle Analysis (LCA). The full LCA system, as described in ISO 14044, involves analysing all the environmental impacts of a product from cradle to grave. The study, initiated in 1993 by the EU, and carried out by a firm of consultants, developed criteria for awarding the eco-label to indoor wall paints. They came to the conclusion that the main environmental impacts were VOC emissions and the high level of energy used

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in the production of TiO2 [1]. Two of the main criteria for qualifying for an eco-label are therefore firstly to have a VOC level of less than 15 g/l (including water in the formulation) and secondly to reduce the TiO2 level. Opacity must, however, be maintained through efficient dispersion and other formulating techniques, such as the use of microvoid technology. The success of this scheme can be judged by the fact that it has remained virtually unchanged in the 18 years of its existence. LCA data exists on an interior acrylic gloss paint, compared to solvent-borne and water-borne alkyds [2]. Six criteria are listed: cost (total cost of paint over a 20 year period), emissions (carbon and other gases), energy, raw-materials reduction, non-renewable/recyclable raw materials and waste reduction as well as health and safety risks. The water-borne acrylic is superior to its solvent-borne equivalent and water-borne alkyd in every respect. This is partly due to a claim of better durability over a 20 year period. The acrylic paint require maintenance only once after 10 years whereas the alkyd paints need maintenance every five years. The study illustrates the critical importance of accurate measurement of service life, as it has a directly proportional effect on the paint’s environmental impact. The authors of the analysis acknowledge that this is a preliminary result and that it is difficult to generalise about classes of product, due to the wide range in performance within a product range. Further open debate is called for, in the spirit of improving the industry’s knowledge. Another methodology is Streamlined Life Cycle Analysis - SLCA - (also referred to as the Sustainability Life Cycle Analysis) [3]. It was embraced by one paint company and one polymer manufacturer in 2008. Since then, both firms have been taken over, so its future use is unclear. SLCA is a technique which enables a company rapidly to focus on areas of activity across the life cycle of a product, which have the greatest environmental impact. The promoters claim that the process can identify 80% of the impacts in a fraction of the time taken to conduct a full LCA.

Carboon foot print analysis An alternative to LCA is the analysis of a product’s carbon footprint. As for LCA, the impact of a product is evaluated over its complete life cycle, but only with respect to greenhouse gas emissions. The main greenhouse gases (GHG) are CO2, methane and nitrous oxide, together with hydrofluorocarbons and perfluorocarbons. It is customary to express a carbon footprint in terms of the amount of carbon dioxide, or its equivalent of other GHG’s emitted, referred to as CO2e. It is therefore a sub-set of the more comprehensive LCA and does not differentiate, for example, between bio-renewable


Technical Paper Architectural coatings Results at a glance To be sustainable, paint ingredients should meet the basic criteria of minimising damage to the environment and, where possible, being based on renewable sources. This requires measurement using such methods as Life Cycle Analysis and carbon-footprint calculations. The complexity of conducting Life Cycle Analysis and carbon-footprint calculations highlights the need for greater cooperation between the participants in the supply chain. The performance of a paint needs to be included as part of the lifetime environmental impact. There are critical components of the major resin types for which there is at present no obvious route from natural sources. It may be many years before architectural coatings based on 100% bio-polymers, matching the cost and performance of current technology, are available.

raw materials and petroleum-based raw materials, but just states the differences in CO2 emissions. The British Standards Institute has issued a Publicly Available Specification PAS 2050:2008 entitled “Specification for the assessment of the life cycle greenhouse gas emissions of goods and services” [4]. A free software package called CCaLC Carbon Footprinting Tool has recently been made available and described in the paint context [5]. It was developed by a consortium led by the University of Manchester and is based on Excel. The approach follows the methodology as defined by ISO 14044 and PAS 2050:2008. Two grades of water-based interior wall paint were analysed over their life cycles using this technique. The carbon footprint for the production of a marketentry paint was 6.35 kg CO2e per 10 litres, while the figure for a high performance paint was 18.1 kg CO2e per 10 litres (Table 1). The study considers the effect of application rate to achieve the desired opacity (to cover an area of 100 sqm.), the comparative durability and the effect of paint wasted due to spillage, cleaning and being excess to requirements. One conclusion is that, if the surface needs to be repainted after a short period, for example, to change the colour for aesthetic reasons, the use of a lower quality wall paint may be better for the environment. A UK paint company has attempted to measure the carbon footprint of some of their paints [6]. They started by asking

European Coatings Tech Files

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Technical Paper Architectural coatings Market entry

High performance

33%

58%

Binder

31%

27%

Production

20%

8%

Pigment

Table 1: Global warming potential of a market entry and high-performance wall paint

Other

16%

7%

Total

100%

100%

Total kg CO2e per 10 l container

6.35

18.1

Table 2: Global warming potential of four trim paints Solventbased alkyd

Waterbased acrylic

Polyurethane dispersion

Alkyd emulsion

25%

29%

43%

52%

Resin

15%

46%

37%

40%

Solvent

56%

21%

13%

0%

Pigment

Other

4%

4%

7%

8%

Total

100%

100%

100%

100%

0.80

0.69

0.49

0.39

Total kg CO2e to coat 1 m2 with a layer thickness of 60 microns

their suppliers for the carbon footprint of their products. The response was either that the data had not been calculated, or if it had, the supplier was not confident that it would fit the paint company’s calculations or compare well with those of their competitors. The data provided by their suppliers varied wildly and each set of figures had their own conditions of analysis and interpretation. The paint company then conducted a preliminary scoping exercise with a consultancy firm, to compare a standard water-borne white matt paint and a standard solventborne white gloss paint, using TiO2 from two different processes. The results showed that TiO2 accounts for more than 50% of the overall footprint of the water-based wall paint formulation. This is in line with the CCaLC data. The paint company concluded that the carbon footprint value on its own is not useful, as it does not take into account performance, which can be translated into maintenance cycles. For an interior wall paint, scrub resistance at equal opacity is probably the best criteria. According to the company’s Lifecycle and Sustainable Smart Maintenance (LSSM) scale, their “eco” matt paint has 30% less CO2e per unit performance than their conventional matt paint. Finally, a major resins company has reported carbon-footprint data for four decorative paints based on different binders, in terms of CO2e derived from coating area of 1 m2 and with a layer thickness of 60 microns [7] (Table 2). For the alkyd gloss paint, the two studies agree on the relative contribution of the pigment to the Global Warming Potential (GWP), but differ over the relative contributions of resin and solvent.

Bio-renewable polymer technology To achieve true sustainability, the coatings industry needs, in the long term, to develop polymers from renewable resources, rather than from finite petroleum-based sources.

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In this new “green” world, oil refineries would be replaced by bio-refineries, and chemists by bio-chemists and molecular biologists. A French company has already built a bio-refinery in Northern France which uses starch obtained from maize, wheat and potatoes to generate a range of chemical intermediates. They and a resin company have formed a joint venture to develop a succinic acid plant, for possible use in alkyd production. Bio-succinic acid is also under development by other companies. A Swedish chemical company has published a technical information leaflet [8] describing the use of bio-glycerol in air-drying and stoving alkyds. The bio-glycerol used is a by-product from a Swedish rapeseed oil bio-refinery. The starting-point formulation contains bio-glycerol, phthalic anhydride and soybean oil. The resin formulation is approximately two-thirds bio-based. They claim that the performance of these products is comparable to that of alkyds based on standard polyols. Two speakers at the 2010 American Coatings Congress described the joint development of a family of alkyd products incorporating sucrose esters [9], [10]. Sucrose polyesters were produced by esterifying sucrose with fatty-acid methyl esters derived from vegetable oils. They can be used in alkyd resins as a non-volatile diluent that reacts into the polymer film during the auto-oxidative cross-linking process. Alternatively, they can be reacted into the backbone of the polymer. The sucrose polyester displaces the pentaerythritol and isophthallic acids in a conventional alkyd, resulting in a system with high (not specified by the speaker) renewable content. The production of a 100% bio-urethane requires the use of a bio-based isocyanate. However, as the isocyanate molecule is not found in nature, it may be many years before a viable natural route is identified. Meanwhile, there are a number of examples of the development of bio-based polyols, leading at least to a partial bio-urethane. A paper from Fraunhofer WKI institute in Germany on “White biotechnology for the wood coatings industry” describes the use of biogenic 1,3-propanediol (produced from glycerol) to replace 1,6-hexanediol to give a urethane resin with up to 34% bio-renewable material [11]. The author mentions extending the process in the foreseeable future to raise the biogenic portion to over 70%. Another example of PUDs based on natural oil polyols exists [12]. Polyester polyols have been produced from seed oil with high, but unspecified, renewable content. Highly engineered natural oil polyols are being developed, from which PUDs suitable for wood coating applications have been synthesised with aliphatic isocyanates. East Michigan University in the U.S. has also reported work on PUDs with high bio-based content [13]. PUDs based on a novel polyol derived from soybean oil, with bio-based content up to ~ 60%, demonstrate an interesting balance of properties. Current commercial acrylic polymers are highly sophisticated products, consisting typically of combinations of butyl acrylate, 2-ethyl hexyl acrylate and methyl methacrylate. These monomers are manufactured in massive quantities in processes which have been developed and refined over many years. To synthesis these monomers from natural sources at appropriate purity and cost will be a huge exercise, especially if non-food crops are specified as the starting point. An alternative approach would be to develop new starting


Technical Paper Architectural coatings materials, but this would discard 50 years of development of sophisticated polymerisation technology, with their appropriate stabilisation, particle-size control and morphology. In principle, bio-ethyl acrylate could be made from the reaction between bio-ethanol (e.g. from corn) and bio-acrylic acid. There are two possible routes to bio-acrylic acid, from glucose to 3-Hydroxypropionic acid to acrylic acid [6], or glycerol to acrolein to acrylic acid [14] (Figure 1). In principle, bio-butyl acrylate could be made in a similar manner, with bio-butanol being made, for example, by fermentation of sugar beet. A company in California has launched its first facility to make bio-butanol from forest waste residues [15] (Figure 2). Currently there is no commercial route to bio-methyl methacrylate, although a study was announced in April 2007 to investigate production from switchgrass in a joint venture with an energy crop company [16].

Figure 1: Possible route to EA/MMA bio-acrylic copolymer

References 1.

Ecobilan, European Ecolabel, Project for application to Paints and

Varnishes, Volume 5, Results of the Extension Phase, 23 December 1993. 2.

Trapani A., Paper 4, Proceedings of the 7th PRA International

Woodcoatings Congress, Amsterdam, 12 – 13 October, 2010. 3.

SLCA, www.forumforthefuture.com.

4.

www.bsigroup.com.

5.

Stichnothe H., Paper 2, Proceedings of the 7th PRA International

Woodcoatings Congress, Amsterdam, 12 – 13 October, 2010. 6. Yates C., Manchester OCCA Strategic Sustainability in the Surface

Figure 2: Possible route to BA/MMA bio-acrylic copolymer

Coatings Industry seminar, 1 March 2010. 7.

Besamusca J., CEPE Annual Conference, Istanbul, 22 -24 September, 2010.

8. Perstorp AB, Technical Information Leaflet TI 0176. 9.

Ryer D.A., Enouen R.J., American Coatings Conference, Charlotte,

12 – 14 April, 2010, Keynote Presentation. 10. Rogers N., Eslinger D., Arredondo V., American Coatings Confer-

13. Mannari V., Rengasamy S., American Coatings Conference, 2010,

ence, Charlotte, 12 – 14 April, 2010, Paper 13.2.

Paper 13.6.

11. Friebel S., Philipp C., Eschig C., Baumann U., Paper 2, Proceedings

14. Arkema press release, 8 March, 2010, www.arkema.com.

of the 6th Woodcoatings Congress, Amsterdam, 14 – 15 October, 2008.

15.

12. Trapani A., Argyropoulos J., Erdem B., Najundiah K., Subramonian

16. Rohm and Haas press release, 30 April, 2007, www.rohmhaas.com.

Cobalt Technologies press release, 12 January, 2010, www.cobalttech.com.

S., Polymers, Paint, Colour Journal, April 2010, p.19.

Oxylink

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43

Events The Coatings Summit

Actively shaping the future Industry managers from 24 countries convene for the 5th Coatings Summit Miriam von Bardeleben This year’s Coatings Summit, held from 17 to 19 January 2011 in Washington DC, outshone all of its predecessors. With some 120 participants representing a total of 24 countries, senior managers from the paints and surface coatings industry gathered to listen to the thoughts of eminent industry leaders such as Hans Wijers of AkzoNobel and Christopher Connor, Sherwin-Williams Company, and Kenji Sakai of Nippon Paint on what will be most influential for the future of the global paints and coatings industry. For more events: www.europeancoatings.com/ events

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This year’s programme afforded deep insights into the development of the global paints and surface coatings industry. Hans Wijers, CEO of AkzoNobel, spoke about the prospects for the global coatings industry. He pointed out that it had been on an upward trajectory for decades.


02 l 2011

This should not be forgotten in times of crisis, he said, and we should invest confidently in the future. He added that the biggest challenges for the future of the industry were urbanization, the carbon footprint and the coatings industry’s image. To illustrate the importance of urbanization for the future demand for paint and coatings, Wijers explained that, by the time 2030 came around, 60 % of the world’s population) would be city dwellers. China alone would have 279 cities with more than 1 million inhabitants by 2020, up from 88 in 2010.

Challenge: Carbon Footprint can only be met by everyone pulling together True, the coatings industry had a smaller carbon footprint than either of the supply side or the consumption side, but even though the industry was not the main cause


Events The Coatings Summit of the problem, it simply could not ignore it. This was a huge challenge that could only be met by everyone pulling together. Another major task for the industry, he said, was the need to polish up its image. The coatings industry had to be made more attractive to all of society, especially the younger generation.

“No project is sustainable unless it is economical too” One of the areas covered by Charles O. Holliday Holliday, Chairman of Bank of America, in his address was the everpresent topic of sustainability in the coatings industry. He maintained that sustainable projects should be pursued only if they make economic sense. Simply feeling good about doing the right thing or demonstrating the environmental awareness of one’s company were not good reasons. No project was sustainable, he noted, unless it was economical too.

Outside current business models: The "new normal"

Coatings Summit

Paul Hodges, Chairman of International eChem, stated that coatings manufacturers had to get used to a situation that he calls "the new normal". As he does not believe in sales volumes to become comparable to those achieved before the crisis, the coatings industry's traditional business models have to be adapted. "We need a new business model, based on shared value", said Hodges.

Learning from peers The remarks by Erkki Järvinen, President & CEO of Tikkurila Oyj, Finland, on the prospects for coatings manufacturers in Russia and the Baltic States went down particularly well with attendees. He not only shared his knowledge on the structure and characteristics of these markets, but also shed light on the considerable potential for error which business activities in these regions could bring with them. Järvinen recounted some lessons that Tikkurila had learned over the years in terms of manpower and distribution channels in Russia.

Coatings Summit

Achieving success together For the first time in the history of the Coatings Summit, which is traditionally organised by the International Paint and Printing Ink Council (IPPIC) and Vincentz Network, key customers of the paints and surface coatings industry took to the podium: Maureen E. Midgley Midgley, Executive Director, Global Paint and Polymer Engineering, General Motors, discussed the importance of perception with respect to the quality of coatings, while, for his part, Glenn Robert Dalby Dalby, Boeing, revealed how coatings were essential to the economics of aircraft operations. By their very presence and their contributions, these two speakers demonstrated that the industry needs to look beyond the value chain and to keep engaging in open dialogue with partners, peers and customers – which also represents one of the reasons why the 5th Coatings Summit was such an outstanding success.


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Market Place Novel products Melt index tester for precise measurements

UV-curable polyurethane dispersion

With the “Ceast MMF Multiweight 7028”, Instron presents a new melt index tester for highly precise MFR and MVR measurements by single weight and multiple weight determinations, for use in quality assurance and incoming goods inspection, R&D centres and indeed other applications. The new tester is suitable for running series of tests automatically using up to five pre-installed weights. These can be selected in increasing or decreasing order or, with the new system, in any order. Measurements can be taken to ISO 1133 A and B, ASTM D 1238 procedures A, B, C and multiple weight procedure D. Piston displacement can be measured at a resolution of 0.02 mm (or optionally 0.005 mm) and this, with the narrow tolerance range and uniformity of temperature control in the cylinder (50 °C to 400 °C, optionally 500 °C, ± 0.1 °C), gives a high level of reproducibility in the test results. This makes the system already ideally suited to the demanding specifications of ISO/DIS 1133 Part 2, which is currently under development.

Cytec Industries Inc. launches “Ucecoat 7710”, a new aliphatic UV-curable polyurethane dispersion resin for high gloss mirror effect. Due to this characteristic, the material opens new possibilities for clear topcoats on wood furniture and plastic substrates. The UV-curable resin distinguishes itself through its high solids content, good hardness and scratch resistance. In addition, it allows for easy finishing as no sanding is required to achieve the high gloss mirror effect. Cytec Industries Inc. BE-Brussels [email protected] www.cytec.com

Centralised wireless monitoring

Instron Deutschland GmbH DE-Pfungstadt [email protected] www.instron.de

Uniaxial tester extends measuring ability Freeman Technology has added a uniaxial powder tester to the “FT4 Powder Rheo meter”, extending the system’s ability to efficiently and reproducibly measure properties that directly correlate with a powder’s in-process behaviour. Uniaxial testing complements the system’s existing test methodologies for shear, bulk and dynamic powder measurement. The method involves measuring the force needed to break or fracture a column of consolidated powder. It is probably the most simple and direct method of measuring unconfined yield strength, a parameter related to cohesivity. The new accessory, in combination with a well-defined consolidation methodology, produces a homogeneous, uniform powder column for testing. Measuring the normal stress required to fracture the column directly identifies the unconfined yield strength. Comparative tests show that the new solution produces data closely comparable to those derived from shear test data, but offers improved repeatability.

Environmentally friendly water treatment “ActiDes” guarantees bacteria- and virus-free water while being environmentally friendly, reliable and economical. The patented method uses electrolysis to produce germ-free water without the addition of chlorine or other chemicals. Quality is guaranteed and consistent, giving pure water that does not suffer from odour or an unpleasant colour or taste. Greater potential for re-use means that the consumption of fresh water is reduced. And there is no longer any need for a regular thermal disinfection of the water system in buildings, since the method ensures that the water itself is germ-free. This makes considerable savings on a company’s energy consumption. Filter equipment does not need to undergo maintenance or replacement so often. The fact that the water cycle can be kept at a lower temperature also provides significant savings.

“Newsteo” is a centralised, wireless monitoring system for any application, sector or area, including warehousing, cool room monitoring, the laboratory and industrial and general room monitoring. It can be used to monitor temperature, humidity or any other parameter simply, reliably and inexpensively. The basis of the “Newsteo Plug & Play monitoring system” is that wireless data loggers store captured data and continuously transmit it to a receiver which monitors it from a centralised position – with an impressive transmission range of up to 900 m. Users can pre-set threshold values and receive alerts when these are exceeded. Set-up of the wireless monitoring system is simple, taking only a few minutes.

Freeman Technology GB-Welland [email protected] www.freemantech.co.uk

ActiDes GmbH DE-Berlin [email protected] www.actides.de

CiK Solutions GmbH DE-Karlsruhe [email protected] www.cik-solutions.com

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02 l 2011


Market Place Novel products Secure storage of flammable substances Covering about 150 pages with colour illustrations – making it more comprehensive than ever – the new catalogue from Protectoplus Lager- und Umwelttechnik GmbH is now available from the company, which specialises in the secure storage of water-hazardous and flammable substances. Everything that customers from industry, commerce, trades and local authorities need to know about products and services relating to internal environmental protection is presented clearly and in detail in the “new Protecto”. New additions to the range include a bigger selection of fireproof storage facilities, technical and safety rooms and warehouses for hazardous materials. And more space than ever is given to the presentation of the individual services offered by the specialists at Protecto, both in supplying standard products and in solving specific problems. Protectoplus Lager- und Umwelttechnik GmbH DE-Rendsburg [email protected] www.protectoplus.de


More than elemental analysis The “Multi EA 5000” is versatile, reliable, easy to operate and capable of much more than just elemental analysis. Carbon, nitrogen, sulfur and chlorine from solid, liquid, pasty and gaseous samples represent only a small part of the range it can handle. TOC, EOX and AOX/TOX analyses are further areas covered by the unit: it can be used in such fields as petrochemicals, environmental analysis, pharmacy, chemicals or materials testing. Its modular design allows the system to be set up individually, and the “double furnace” technology makes it quick to switch between vertical and horizontal applications in one instrument, so it can be adapted quickly to the sample matrix concerned and standard analysis is straightforward. The use of only a single multipurpose combustion tube for all standard applications, whether in the vertical or horizontal mode, does away with the need to change tubes. Analytik Jena AG DE-Jena [email protected] www.analytik-jena.de

Laboratory robot for automated sample preparation The quick and compact laboratory platform “sciLine.speed” from Manz is now available with new modules for sample preparation – weighing, dissolving and filtration – and yet occupies less than 0.8 x 1.2 m of space in the lab. The new unit with combined ultrasound and agitation and the parallel filtration module enable analytical and compound logistics laboratories to carry out parallel sample preparation tasks reliably. Advantages include high sample throughput requiring little staff attendance, good reproducibility as a result of high precision, and good preparedness for inspection thanks to excellent documentation of the operational procedures. In combination with the optional “Microdos” solids dosing module, it is now possible to prepare vials for analytics, screening plates and other solid or fluid sample formats completely automatically and in a minimum of space. Manz Automation AG DE-Reutlingen [email protected] www.manz-automation.de

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47

Market Place Novel products Stirrer system is more flexible

System brings together three clean-up methods

Promitec GmbH has made its universal high-tech stirrer system more flexible. The system has cup-shaped agitator elements which are open on both sides. In the “PRO Con” model, which is intended for use in intermediate bulk containers (IBCs) of 600 to 1000 litres, the agitator elements can now be replaced quickly and easily, by way of a cleverly designed bayonet closure. This means that users – such as resin and paint manufacturing and processing companies, or pharma, foodstuffs and chemical companies – can use different agitators with different batches, flexibly and easily, without having to change the whole shaft or even the entire drive. In addition, the bayonet closure makes it easier to clean the agitators. Just swivel them into the change-over position, and they can be removed individually and put into a solvent bath or cleaning station. Promitec GmbH DE-Schopfheim Flow cell for ultrasonic [email protected] processes www.promitec.de

FMS has launched the first and only sample preparation system that combines three different sample prep processes in one unit. The “TRP-Total-Rapid-Prep” performs extraction, sample clean-up and concentration for six samples simultaneously in a matter of a few hours, and the manufacturer reports that it gives extremely high yields and excellent results for all analytes. The system is controlled by easy-to-use, Windows-based, fully programmable software. It increases sample throughput while reducing operating errors and poor yield rates. It also ensures that analysis is carried out in clean conditions, eliminating cross contamination due to its closed cycle design. The unit utilises FMS’s high-quality and inexpensive Teflon-based prepacked disposable columns, guaranteeing high yields and eliminating the need for glassware clean-up.

Hielscher Ultrasonics launches a new stainless steel flow cell, especially developed for highly intensive ultrasonic processes of small volumes. The flow cell “fc2clampk” fits to the company’s industrial ultrasonic processors UIP500hd (20kHz, 500W), UIP1000hd (20kHz, 1kW), UIP1500hd (20kHz, 1,5kW) and 2000hd (20kHz, 2kW). Its high energy input into the liquid processing medium and its small volume make the flow cell a suitable tool for the nano, pharma and biotech industries. Hielscher ultrasonic devices are used for emulsifying, dispersing, deagglomeration, and extraction. The ultrasonic reactor features a cooling jacket that allows to control the temperature also during high energy input. The new flow cell is made of stainless steel, has simple geometries and can easily be disassembled and wiped out. There are no small orifices or hidden corners. This is of high importance when small amounts of material have to be sonicated. The simple design of the flow cell avoids settling material in corners or orifices so that the substance does not get lost. Hielscher Ultrasonics GmbH DE-Teltow [email protected] www.hielscher.com

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Acrylic resin for bottle labeling adhesives “NeoCryl BT-207” is a new, waterborne acrylic resin for bottle labeling adhesive applications. This resin is especially designed for adhesives to be used in high speed and cold-fill bottle labeling, combining high performance with high stability. For a long time, adhesive formulators have been searching for synthetic resins for bottle labeling applications in order to relieve supply constraints, and performance variations of the traditional solution – casein. The new product has closed the performance gap offering adhesive formulators an improved alternative to natural casein. The resin offers good wet tack, glass adhesion and resolubility features, comparable to optimal casein performance. In addition, being a synthetic resin with consistent quality, it provides the adhesive manufacturer the benefit of robust production, eliminating the need for batch to batch adjustments as often is the case with today’s solutions. DSM NeoResins+ NL-Waalwijk [email protected] www.dsmneoresins.com

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Campro Scientific GmbH DE-Berlin [email protected] www.campro.eu

Non-slip coating to avoid corrosion Metallisation Ltd has launched a new durable non-slip coating which can be used on steel floors, decks and panels across diverse industries, from train steps to oil platforms. Untreated these steel surfaces can become very slippery, especially in wet conditions, and are prone to corrosion. To ensure safe walking and industrial operating conditions, vital to personal safety and corporate productivity, “28E Arctec” coating provides a durable non-slip anti-corrosion coating. The new product is a thermally sprayed coating that can be applied with a rough texture and has good non-slip properties, while being extremely hard and resistant to wear. It provides a suitable level of grip, to avoid personal slips or industrial skidding, comparable corrosion protection to aluminium, as used in aggressive environments, and easy application by a long-standing process, covered by international standards. Metallisation GB-Dudley [email protected] www.metallisation.com


Market Place Novel products Exposure technology based on UV irradiation The “Nyloflex NExT” exposure technology from Flint Group Flexographic Products, based on high-output UV technology, is able to generate specific element shapes with precisely reproduced surfaces, commonly known as Flat Top Dots. This new technology provides all the benefits of these structures, such as increased tonal range and specific surface raster structures, to improve solid ink density in the printed product. The main advantage of the technology is that it does not involve the use of inert gases (with all the risks that entails) or require expensive consumables. No new steps, such as film or negative film lamination, are added to the standard digital workflow. The new exposure technology is expected to be commercially available in 2011. Flint Group Germany GmbH DE-Stuttgart [email protected] www.flintgrp.com

Secure and simple data management Manufacturers in the chemical industry today have to cover a wide variety of products while responding quickly to changing market requirements. In addition, they have to meet high safety standards and provide the proof of compliance required by legislation. The “ProBatch+” recipe and production management system provides many advantages for meeting these requirements, thanks to its high performance and great flexibility. In particular, it boasts easy installation and start-up, and intuitive operation. The system runs under Windows and uses the powerful MS Access database to manage large quantities of data on raw materials, recipes and production data easily and securely. The ease of handling and operation brings substantial savings, in terms of both time and money; and short learning times for operating personnel result in reliable operation.

INTERNATIONAL SPECI

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02 l 2011


49

Calendar of Events 2011 Conferences 7 – 9 February 2011 Pipeline Coating 2011 Vienna, Austria www2.amiplastics.com 8 – 9 February 2011 European Coatings Conference: Easy-to-clean/ self-cleaning coatings III Berlin/Germany www.european-coatings.com/ events/ecc.cfm 10 – 11 February 2011 European Coatings Conference: Biobased coatings II Berlin/Germany www.european-coatings.com/ events/ecc.cfm 28 – 30 March 2011 European Coatings Congress 2011 Nuremberg/Germany www.european-coatings-show. com/en/congress/

31 March – 1 April 2011 EuPIA Annual Conference Vienna/Austria www.eupia.org

Exhibitions 29 – 31 March 2011 European Coatings Show 2011 Nuremberg/Germany www.european-coatings-show. com/en/

Seminars

19 – 22 April, 2011 Primus: Interfarba 2011 Kiev, Ukraine www.theprimus.com/en/inwww.theprimus.com/en/in terfarba

7 March 2011 Functional Raw Materials and Coatings Salford/UK www.occa.org.uk

11 – 13 May 2011 COAT EXPO 2011 Guangzhou/China www.coatexpo.cn/en/

15 – 16 March 2011 Principles of Waterborne Coatings Hampton, Middlesex, UK www.pra-world.com

5 – 7 April 2011 Print and Ink Technology Hampton, Middlesex, UK www.pra-world.com



10 – 12 April 2011 Radiation Curing Technology Hampton, Middlesex, UK www.pra-world.com

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More coatings events at www.european-coatings.com/ events

European Coatings Conferences Extra

ce Pre-conferen

Berlin/Germany

Pictures: Anyka - Fotolia.com, M.Beßler©Pixelio.com Paolo Toscani - Fotolia.com

tutorials

Focusing on current developments in raw materials as well as mechanisms and standards the European Coatings Conferences will provide you with ideal networking opportunities and up-to-date information, presenting a suite of high-level technical papers, given by invited international experts. Coming up next!

Novel biocide technology

Waterborne clearcoats III

Improving durability of coatings

12/13 April 2011

10/11 May 2011

7/8 June 2011

 Latest news on the Biocidal Product Directive  Solutions for dry-film and in-can preservation  Biocides for antifouling paints

 Improving durability of waterborne clearcoats  Latest developments on fillers and additives for waterbased technology  Solutions for UV-coatings

 Novel binder technologies  Advanced formulations  New methods of enhancing performance

Detailed programmes, abstracts Coatingsat J OURNAL 01 l 2011 and onlineEuropean registration www.european-coatings.com

Nicole Steinbach · Project Manager Events Tel. +49 511 9910-274 [email protected]


Reader's contribution 02 | 11

Readers provide technical insights How to write for “European Coatings Journal” General remarks We always start out from the premise that we are allowed to publish what we receive. If you're not certain whether a particular subject is right for “European Coatings Journal”, just contact us. Receipt of your manuscript is acknowledged immediately, and within four weeks you'll know whether your article is going to be published and, if so, when. Once it has been accepted for publication, we are deemed to have acquired the right to use it in other of our publications and media, such as databanks, CD-ROM, on-line offers, internet. We expect your article to make a real contribution towards promoting knowledge about the subject of the article and/or be of real practical use. It should not be written from an obviously advertising point of view. Trade names should be avoided wherever possible and be replaced by neutral terms.

Manuscript guidelines The manuscript should have approx. 15,000 characters incl. blanks (we schedule 4 printed pages per article) and 8 graphic elements such as tables, illustrations, formulas or photographs. Please send all images in a separate file, in TIF or JPG version, minimum 300 dpi. Please also send the Excel tables that the graphs are based on. Manuscripts need to be written in English. A full paper includes: - Head - Subhead - Authors´ name(s) - Leader - Main text - Interlines


Previous or concurrent publication in any other journal (including those outside Germany) will render void this acceptance. Reprints are subject to our consent. The editors reserve the right to make reasonable amendments, abridgments, etc. The layout of the article and date of publication are subject to the editors' decision. By accepting the article for publication, we also acquire the right to use it in any form of electronic media. The author declares that the rights of third parties are neither excluded nor in any way infringed or violated by the dissemination of the content of the article in any form whatsoever. Any claims against Vincentz Network arising from the disregard of this release by the author shall be enforceable against the author.

Your contact: Kirsten Wrede European Coatings Journal Vincentz Network P.O. Box 6247 30062 Hanover Germany T +49 511 9910-212 F +49 511 9910-299 [email protected] www.european-coatings.com

- Figures - Tables - Results at a glance - Literature - Contact details - Application related photo

02 l 2011


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