Currently, consumption of plastic coatings is outpacing the paints market as a whole. In a recent report on plastic coatings in Western Europe, IRL, the London-based market research organization, estimated that the sector was growing at an annual rate of 3.4%. This was significantly above the average increase in all coatings sales in the region and considerably ahead of average GDP growth in the European Union.
Demand for plastic coatings has been mostly driven by the automotive industry, which accounts for around half of sales. The desire among European consumers for more color has led to car manufacturers wanting coated plastic components.
Plastic coatings are also becoming more popular in sectors like electronics, particularly with products such as mobile phones in which there is a trend to special visual effects and personalization of colors. In addition, changes in architectural designs, especially in interior décor, are helping to bolster sales.
Producers of conventional plastic coatings are facing strong competition not only from the predominant coloring systems of masterbatches and compounds, which enable pigments to be dispersed within the plastic product. They are also being confronted by new technologies such as the use of formable film inserts to enable in-mold decoration (IMD) of plastic.
In addition, plastic coatings suppliers are facing difficulties with new EU recycling regulations covering automobiles and electronic and electrical appliances. To comply with the rules, which could necessitate the stripping of paints from plastic parts, OEMs may decide to do without coatings.
Also problems with adhesion, stability and other high performance requirements with certain polymer substrates are still posing a technological challenge to plastic coatings formulators.
OEMs want coatings which not only adhere well but also have good scratch resistance, weatherfastness and also strong colors. They also have to be applied to a widening range of plastics with different pre-treatment needs.
At the same time in some applications coatings are expected to be functional and tactile as well as decorative. Coatings are applied not only to improve appearance but also to give protection against chemicals and physical stress and even to provide "smart" capabilities
Mainly due to new EU restrictions on emissions of volatile organic compounds (VOCs) plastic coatings will tend to have to be waterborne and UV-cured. Unfortunately in the key area of adhesion a lot of R&D work may still be necessary because of a lack of scientific understanding about the issue and even an absence of reliable tests to help advance knowledge of the problem.
Nonetheless a big impetus behind the rise in sales in plastic coatings is the perception that in certain circumstances their performance as colorants can be superior to that of masterbatches and compounds.
In the wake of rising input costs, stemming from high oil prices, plastic processors have been complaining about deficiencies in color masterbatches. They claim that manufacturers of high performance pigments have not been investing enough into research into new colorants which would deal with problems of high heat processes, stability, dispersibility and limits in the range of colors in some parts of the spectrum.
Masterbatch producers are meeting tougher competition from other coloring methods, particularly coatings, because of the inability to exploit properly the full potential of new colors and optical effects now part of the palette of most designers.
"There are difficulties with applying metallic and pearlescent effect pigments to plastics in master batches or compounds," said an executive in the polymer processing sector. "The flakes in the pigments need to be carefully orientated in order to achieve full brightness and brilliance. Obviously that is much more easily done with coatings."
The prospects for plastic coatings have also been boosted by a steady widening of the utilization of plastics, especially in sectors like automobiles and furniture. At the same time, with the shift to personalization of designs, plastic coatings can provide individual colors and textures.
"Plastics, presented in high gloss, are among the most favored materials (in furniture)," concluded the German red dot design promotion organization in a report on furniture trends in 2005.
What is happening in the furniture market is reflecting a general swing away from designs for the "universal consumers" to ones which meet the demands of specific target-groups, according to red dot.
In the European automobile sector, plastics are being combined with a large variety of materials in the interiors of new cars, including leather, textiles, wood and metals. There is a similar tendency in the interiors of passenger aircraft.
"The car manufacturers want to use a lot of different materials in the interiors because it enables them to satisfy the needs of particular groups of consumers," explained a designer at one European plastic coatings maker. "They want the plastics in these interiors to be coated because then they gain much more flexibility and scope for differentiation. They have a much bigger choice of colors and surface textures. The latest fashion is to have interiors with different materials but with a single color, such as white or another light color. But the plastics need to be coated so that there can be modifications within the single color theme."
Plastic coatings are contending with IMD systems in the design of both interiors and exteriors of new cars. In-mold decorating can be suitable for parts of the dashboard which are frequently touched by the driver. If coated the surfaces would be susceptible to erosion.
However IMD is probably facing more problems with the EU's recycling regulations than plastic coatings are. Recent tests on film insert molding materials have shown they may not be suitable for reuse after recycling.
More significantly, coatings producers are in a better position to ensure that their plastic paints are consistent in colors and quality with the appearance of other parts of the car. BASF Coatings recently agreed to collaborate with Plastic Omnium, the French-based maker of plastic automobile parts and modules, on the use of color management concepts in plastic coatings in order to improve color specifications and prevent color deviations.