What Kind of Plastic Is Used for Car Bumpers?

Car bumpers are a vehicle's first line of defense from the bump and grind of the outside world. Car bumpers need to be able to absorb shock and offer an aerodynamic surface for cutting through atmospheric air at high speed.

Materials

The car bumper has been made from all types of material. For many decades, bumpers were made of chrome plated steel, which offers a decent amount of protection but is easily dented and quite heavy and expensive. Since the advent of plastics, car bumpers have been made almost exclusively from reinforced thermoplastic olefins. Thermoplastic is easy to form and gives way on impact, acting as a cushion to dissipate energy.

Plastic Properties and Function

The outer shell of the modern car bumper is made of any of a number of thermoplastics. The thermoplastic shell usually covers a denser, almost honeycomb-like composite of dense plastic which is mounted on a metal frame, which is mounted to the chassis of the vehicle. The dense plastic honeycomb is crushed during an impact, absorbing a great deal of energy to protect the rest of the vehicle and the passengers.

Thermoplastic Olefin

A thermoplastic is a plastic which can be heated multiple times and retains its plasticity, or ability to be molded while hot. Thermoplastic has many of the properties of a plastic bottle, which can be thrown across a room and remain undamaged. Thermoplastic olefins are a type used in the automotive industry because of their energy absorbing qualities, ease of manufacture and low cost. Most bumpers today are made of thermoplastic.