The car's bumper is an accessory (wearing parts) of the car body, located in the front of the car (called the front bumper) and the rear (called the rear bumper).
At present, the domestic automobile bumper is generally used toughening (modified) polypropylene (PP) material as raw material injection molding - polypropylene Poly (propylene) plastic (commonly known as PP material), with high melting point (up to 167 ℃), resistance Heat, density (0.90g / cm3), is the most common in the general plastic, a higher corrosion resistance (tensile strength of 30MPa), its products, strength, rigidity and transparency are relatively good characteristics, The disadvantage is poor resistance to low temperature performance (by the impact of PP copolymer, styrene elastomer and polyolefin rubber three kinds of blending modified materials, with high rigidity, impact resistance, scratch resistance and coating, injection After the molding bumper is loaded, the collision by 8 km / h does not break, and has the resilience of recovery, the performance is about the same as PU, the cost is reduced by 10% to 20%).
In 1991, Toyota Motor Co., Ltd. will be nano-PP composite materials used in front and rear bumper, so that the original bumper thickness from 4 mm to 3mm, the product quality reduced by about 1 / At present, more than 90% of the bumper systems in North America are made of polyolefin-based materials. North American automotive industry thermoplastic elastomer (TPO) usage of the annual growth rate of more than 10%. In 2005, TPO accounted for 75% of the North American plastic bumper market, while the use of RIM and PC / PBT bumper content decreased to 20% and 1%.
And some bumper is made of other materials (such as glass fiber reinforced plastic, carbon fiber and other materials), because of its environmental performance (recyclable) poor or higher cost and other factors, are not modified PP material made of bumper (plastic And rigid weight, light weight and thin, low cost has always been the main goal of the production of the bumper), and the general PP material itself, the size of the stability and low temperature resistance is poor, so the next few years the production of car bumper material But also with modified PP materials and increasingly mature thermoplastic elastomers