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Coatings employed for exterior automotive plastic parts have to meet criteria which, in many respects, surpasses those for the metal substrates. They must be comparable in appearance, chemical/solvent resistance, and weatherability. As well, they must cure at temperatures below the deformation temperature of the plastic and be highly flexible to avoid negative effects on low temperature impact values. Two-component (2K) polyurethane coatings have proven to satisfy these requirements and are employed world-wide for this application. Until recently, sanding and polishing such highly elastic coatings was not possible. As a consequence, the repair of small surface imperfections was a very costly and time-consuming operation. A method has been developed, using cryogenic polishing, which allows the sanding and polishing of even the most elastic coatings in a relatively short time.

The coating of plastic substrates, particularly for applications in impact-prone areas of an automobile, requires the coatings technologist to be aware not only of the mechanical properties of the substrate which is to be coated but also of those of the coating, and of the coating/substrate interaction. It is a widely accepted observation that coating a flexible substrate with a relatively rigid paint system will cause premature impact failure of the substrate. This paper provides a detailed examination of the relationship between coating flexibility and substrate impact resistance and offers guidelines to overcome premature impact failure by the use of variably flexible two component urethane paint systems.

Rubber articles with improved heat resistance and better performance characteristics are becoming of increasing importance for the automotive industry. A new type of elastomer has therefore been developed based on saturated hydrocarbon backbone - for improved heat resistance - with nitrile side groups providing good resistance to swelling. Some of the typical characteristics of hydrogenated nitrile rubber (HNBR) vulcanizates such as good physical properties pattern at elevated low temperatures, dynamic properties, ozone resistance and swelling in automotive fluids will be discussed. Potential applications are suggested to improve the performance of various rubber parts used in automotive applications such as high performance seals, hoses for hydraulic systems and oil contact, chain tensioners, timing belts and power transmission belts.