Automobile bumper fascia

Because of low cost, high heat deflection temperature (HDT (104°C)), notched impact resistance, improved low temperature impact and flexibility, weather resistance, flame retardancy, and impact resistance, the PP/EPDM blend has got a widespread applications. These unique characteristics of this thermoplastic elastomer blend make it an attractive alternative to conventional elastomer in a variety of markets such as automobile industries, wire, cable insulator, automobile bumpers and fascia, hose, gaskets, seals, weather stripping, among others. 

The first major growth of RIM processing, as noted earlier in this section, occurred in the United States with the development of automobile bumpers designed to meet Congressionally mandated safety standards in a 5-mph impact. Polyurethane fascia (a term applied to both the front and rear bumpers, as well as fenders and other automobile parts) were designed to cover steel beams mounted on shock absorbers. Later, glass-reinforced RIM (RRIM) products were introduced and applied to some fender and body parts. In 1987, about 150 million pounds (67, 500 metric tons) of material were used for the manufacture of RIM products in the United States. About half of this total is polyether polyol, and about half was used in automobiles. 

Concurrently, automotive demand for increased plastic usage became standard when legislation mandated that automobiles should sustain little or no damage in low-speed collisions. The average weight of plastic utilized in the late 1960s, namely less than 50 pounds per car, jumped dramatically in the 1980s to approximately 250 pounds per car when bumpers, fascias, rub strips, and the like mandated plastic as the material of choice. 

Low modulus elastomers are materials that have found wide use in the automobile industry for fascia, bumper covers, and trim parts. Other applications include integral window seals and a wide variety of applications where it is replacing molded rubber. Most of these materials are not pure polyurethane, but polyurethane/polyurea hybrids with improved processing and properties when compared with the earlier allurethane systems. 

The impetus for developing the RIM process for producing elastomeric fascia parts was furnished by the requirements of the Motor Vehicle Safety Standard 215, which went into effect in 1973. This regulation required that the front and rear ends of automobiles had to withstand a 5 mph. impact without impairment of functional parts. A more stringent regulation, Standard 581, which came into effect for all bumpers made after September 1, 1979, required that the bumper withstand the 5 mph. impact with no more than a 3/8" dent in the bumper itself. 

The first commercial product made from nylon RIM was a front quarter panel (fender) for the Oldsmobile Omega Sport. Because of the excellent impact strength of nylon RIM, it has been used for bumper covers and automobile fascia. It also finds application in housings for business machines and electronics. 

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