Commonly used plastics for automotive interior and exterior parts include PP, PC/ABS, ABS, PE, PA, and POM, among which PP is the most widely used. The following is a brief introduction to these commonly used plastics for automotive interior and exterior parts and their applications.
PP
PP, or polypropylene, is a polymer formed by the free radical polymerization of propylene monomers. It is a non-toxic, odorless, tasteless, high-density, high-crystallinity, milky-white linear polymer. It is also the most widely used plastic material for interior and exterior trim components.
Advantages:
1) Low density (lightest plastic), lightweight;
2) Water absorption rate less than 0.02%, almost completely unaffected by moisture;
3) High impact strength, good processing fluidity, easy to mold, and good product appearance quality;
4) Abundant raw material sources and low price;
5) Good temperature resistance (but poor thermal deformation capacity);
6) Good chemical resistance.
Disadvantages:
It is brittle in low-temperature environments and has poor weather resistance (which can be improved by modification and the addition of additives); it is a crystalline material with a large shrinkage rate and poor dimensional stability.
Applications: PP materials are mainly used in the body of components, such as dashboard bodies, sub-dashboard bodies, glove boxes, storage compartments, door panels, pillar guards, sill plates, seat guards, trunk guards, passenger armrests, front/rear bumper covers, side skirts, lower windshield trim panels, mudguards, etc.
Fiber-reinforced PP materials have high rigidity, especially long glass fiber reinforcement and modified glass fiber mat. They are widely used in structural components, primarily as a metal replacement, and are applied in spare tire compartments, seat frames, door modules, and other components.
ABS
ABS is an amorphous material, a copolymer of acrylonitrile, butadiene, and styrene. It combines the excellent properties of three monomers: acrylonitrile (heat resistance, chemical resistance, high rigidity), butadiene (toughness), and styrene (good processability, good dyeability, poor weather resistance, and easy oxidation). The characteristics of ABS mainly depend on the ratio of the three monomers and the molecular structure in the two phases. By changing the ratio of the three components, the combination method, and the particle size, different varieties can be produced.
Advantages:
Good surface decoration and secondary processing capabilities, including painting, electroplating, welding, and bonding; good dimensional stability and creep resistance.
Disadvantages:
Poor chemical resistance, poor UV resistance (due to butadiene components), high gloss. Low heat resistance, with a relatively low heat distortion temperature.
Applications:
ABS is mainly used in interior and exterior trim components for decorative parts using processes such as painting, electroplating, water transfer printing, and IMD (Integrated Device Modulation). Examples include painted decorative strips, electroplated bright strips, electroplated grilles, electroplated nameplates, and rearview mirror housings. Due to its good dimensional stability, especially high-temperature stability, it is also used in instrument cluster covers, steering column covers, door panel inserts, switch buttons, and air vent panels. Blow-molded ABS can also be used for spoilers.
PC/ABS
PC/ABS is an alloy plastic blend of PC and ABS. PC/ABS blends can combine the excellent properties of both PC and ABS.
Advantages:
Heat resistance, toughness, impact strength (particularly suitable for high-strength structural components), and flame retardancy; good processability, surface quality, and low density. Reduced unit material cost and lower melt viscosity. As an alloy of two amorphous plastics, PC/ABS offers excellent overall performance with no significant drawbacks.
Applications:
PC/ABS is used in decorative parts that require certain heat resistance and high impact resistance, such as electroplated door handles and center console trim panels. Due to its excellent low-temperature performance, dimensional stability, and excellent adhesion to foam, PC/ABS is also commonly used in the dashboard body of high-end vehicles.
