PPG invented and patented a technology for improving the corrosion resistance and the acoustical insulation of some critical parts of a vehicle as underbody and boxed parts. Such an invention, based on a thermoplastic polymeric composition containing heat activated swelling agents, has generated two main coating materials: an expandable underbody coating and a box section gap filler. The immediate performing advantages caused by using these innovative products are: (a) drastic weight reduction of employed materials; (b) remarkably good mechanical performance; (c) improved anticorrosion resistance; (d) increased acoustical insulation level. Together with such an excellent technical behavior, this new PPG technology represents a highly positive innovation also from environmental and toxicological viewpoints. Expandable underbody coating and box section gap filler, both with the common objective of helping create a more silent and durable vehicle, are perfectly integrated into the objectives of a Chemical Industry, i.e. those of proposing safe environment-friendly products safeguarding internal and external surroundings from hazardous materials. (C) 1997 Published by Elsevier Science S.A.
