Ulrich Knipp

Plastics for Automobile Safety Bumpers

Plastics are favored for the production of bumpers. Plastic bumpers can withstand multiple crashes without technical or visual damage. From all the different plastics microcellular urethanes and soft urethanes backed with low resilient semirigid foams showed the best behaviour. There is no problem to produce large self skinning PUR-foam parts. Only low investment is required. The confidence level of self skinning PUR-foams is high. Altogether 33 different plastics and plastic-combinations bumpers were built and tested for a fundamental investigation (Figure 1). The prime criterion was a crash test with a sharp edged load. (Dimension 60 X 120 mm, load 18 kg, speed 7.7 m/sec corresponding 23 mph). At this test it was recorded, if the parts were broken, if they were compressed and if they recovered entirely. After this first test many materials failed. So