Coatings companies in Europe are striving to meet the challenge of reformulating their decorative paints to comply with new strict limits on emissions of volatile organic compounds (VOCs) effective in the European Union (EU) from January 1 next year.
In order to conform with the new limits, manufacturers of decorative coatings are having to make big cuts in the VOC content of their paints-as much as 90% with solventborne paints and even 60% with waterborne.
The vast majority of large decorative paint producers in the EU, which account for more than half of sales in the European markets have been ensuring for some time that their products are compliant with the 2010 VOC restrictions. This is mainly because much of their portfolio has been switched to waterborne.
Otherwise they have opted for high solid paints in which VOC contents has been reduced by making greater use of reactive solvents, new surfactant systems and other modifications.
The high solids route has also tended to be the one chosen by many small- and medium-sized decorative producers in Europe, which have been slower to move over to waterborne paints.
There are well over 1,000 small and medium enterprises (SMEs) in the European decorative sector, according to figures from the European Commission, the EU executive. When localized small businesses, particularly in southern Europe, are included the total rises to more than 3,000.
Waterborne paints have an estimated share of approximately 60% in the decorative market in Europe-one of the largest shares in the world. But there is still an entrenched loyalty to solventborne among small producers and significantly among many professional painters because of their perceived superior qualities.
In the EU's regulation for VOC emissions from decorative paints, which is being implemented in two phases, one from 2007 and the other 2010, the toughest restrictions are on interior paints. The VOC content of solventborne paints for interior matt walls and ceilings has to be cut by 92% from 400 grams per liter to 30 grams per liter by next year and for interior glossy walls and ceilings by 75% to 100 grams per liter.
For solventborne paints for interior and exterior trim and cladding the reduction must be 25% to 300 grams per liter.
"It's a bit of a struggle for small coatings companies to meet the VOC limits," said Hans Ridderikhoff, technical marketing manager at the polymers and coatings operation of Croda International, Gouda, Netherlands. "All paint companies will be complying with the new VOC limits next year. But some will have reformulated quickly to keep within the limits. They will have chosen a temporary solution."
Due mainly to the effects of the economic downturn, many coating companies are selecting low cost technologies to ensure their paints keep within the VOC limits. One common choice has been the application of high solids containing reactive solvents or diluents, which remain in the paint.
A customer survey in 2007 by DSM Resins of the Netherlands, which prompted 200 responses, found dissatisfaction with these types of high solids with a high oil content and low molecular weight because of their low level of hardness and slow drying times.
"What we are seeing at the moment is the commodity part of the decorative market accepting old technology based on oil diluents and low molecular weight components as the solution to VOC compliance despite the deficiencies of low hardness and slow drying times," said Jan Besamusca, innovation director, DSM Resins. "Customers have been influenced by the current economic downturn by choosing what is available at a low cost. The market has accepted the older but more economical solution."
DSM's own solutions are hybrid resins with a narrow molecular weight distribution with a low VOC level and without the drawback of wrinkling or slow drying. "There is a general acceptance that low molecular weight compounds can cause problems," said Besamusca. "Our solution is superior to others but we do have the disadvantage of being more costly."
In its 2007 survey, DSM's customers expected by 2010 the market share in Europe's decorative sector would be 70-30% in favor of water-based coatings with the remainder being solventborne, including high solids.
"We expect that the balance will be 50/50 next year," said Besamusca. "The customers in the 2007 survey were expecting a revolution which is turning out to be only an evolution. The switch to waterborne is not taking place as quickly as expected. Next year's VOC regulatory limits achievable with traditional, low cost, old technologies which have been shown to work better than expected."
Decorative coatings companies are selecting formulations which enable them to carry on using alkyd resins. As a result ingredient suppliers are offering low-VOC alkyd-based systems.
Croda has launched a dispersion system centered on polymeric surfactants whose large molecules offer enough stability to allow water to replace the solvent content of high solids-as much as 20-30%. "The dispersion helps the remaining solvents to be more efficient so that it reduces the amount of solvent, cuts costs and still gives the same performance," said Ridderikhoff. "Coatings formulators can continue to use alkyd resins with only a limited change to the formulation while complying with the VOC limits."
Companies like Rhodia of France are promoting a range of additives as a means for cutting VOC content. These include wetting agents, defoamers, stabilizers and coalescents, which enable the whole formulation to work more efficiently.
"It's not just a reduction in the solvents which helps producers to cut VOCs, but the application of different additives as well," said Adrian Archer, Rhodia's business development director for solvents market.
For many coatings producers the recent priority has been to develop formulations that meet next year's VOC limits in Europe. The next step is to upgrade the performance of these products.
"We see the market becoming quite dynamic," said Archer. "Some formulations have been the same for years. We see a need to improve formulations over the next few years as companies make more use of new technologies. They will be looking to balance cost-in-use and sustainability with performance, which will be a continuous process."
There should also be opportunities for suppliers of low-VOC bio-chemicals. "Most decorative coatings customers are able to meet the VOC regulations with petrochemical solutions," said Shailesh Shah, director global marketing for coatings at Cognis AG of Germany, a specialist in renewables for coatings. "They see a clear need for higher efficiency, improved dirt pick-up resistance and renewable-based chemistry whenever it is possible without a performance sacrifice."
Now that the stricter VOC limits are making coatings companies reformulate they are becoming much more willing to consider innovations in their products.
Making the switch to waterborne formulations is a challenge to industry and raw material suppliers are trying to help paint companies meet those challenges.
By Sean Milmo
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