Commonly used plastics for automotive interior and exterior parts mainly includePP,PC/ABS, ABS, PE, PA, and POM , among which PP is the most used material. Next, we will briefly introduce these commonly used plastics for automotive interior and exterior decoration. and its application.
Polypropylene is a polymer formed by free radical polymerization of propylene monomer . It is a milky white linear polymer with high density, no side chains and high crystallinity, which is non-toxic, odorless and tasteless. It is also the plastic material with the largest amount of interior and exterior parts.
Advantage:
1) Low density (the lightest plastic), light weight;
2) The water absorption rate is less than 0.02%, and it is almost completely free from water erosion;
3) High impact strength, good processing fluidity, easy molding, and good product appearance quality;
4) The source of raw materials is abundant and the price is cheap;
5) Good temperature resistance (but poor thermal load deformation capacity);
6) Good chemical resistance.
Shortcoming:
The low temperature environment is brittle and has poor weathering resistance (it can be improved by modification, adding additives, etc.);
Crystalline material, large shrinkage rate, poor dimensional stability.
Application:
PP materials are mainly used for parts, such as instrument panel body, auxiliary instrument panel body, glove box, storage box, door guard body, pillar guard body, door sill pressure plate, seat guard plate, trunk guard plate , passenger armrests, front/rear bumper skins, side skirt guards, decorative panels under the front windshield, fenders, etc.
Fiber-reinforced PP materials have high rigidity, especially long glass fiber reinforcement and glass fiber mat modification, and are widely used in structural parts, mainly replacing metal, and are used in spare tire compartments, seat frames, and door modules. Wait for the parts.
PP-LGF material door inner panel
PP bumper
Acrylonitrile-butadiene-styrene copolymer is an amorphous material that combines acrylonitrile (heat resistance, chemical resistance, high stiffness), butadiene (toughness), styrene (good processability, dyeing properties) Good performance, poor weather resistance, easy oxidation) excellent properties of the three monomers. The characteristics of ABS mainly depend on the ratio of the three monomers and the molecular structure in the two phases. Different varieties can be produced by changing the ratio of the three components, the compounding method, and the size of the particles.
Advantage:
Surface decoration and secondary processing, including painting, electroplating, welding, bonding, etc.
Good dimensional stability and creep resistance.
Shortcoming:
Because of poor chemical resistance, poor UV resistance, high gloss.
The heat resistance is not high, and the heat distortion temperature is low.
Application:
ABS is mainly used in interior and exterior parts for decorative parts that use painting, electroplating, water transfer printing, IMD and other processes, such as painted decorative strips, electroplated bright strips, electroplated grilles, electroplated signs, rearview mirror housings, etc. At the same time, because of its good dimensional stability, especially high temperature stability, it is also used in combination instrument covers, steering column guards, middle panels of door guards, switch buttons, air outlet panels, etc. Blow molding grade ABS can also be used for the spoiler.
Attention:
Part temperature requirements are the main considerations in deciding to choose different heat-resistant grades of ABS. In addition, due to the poor weather resistance of ABS, it is generally not used for exterior leather parts exposed to direct sunlight.
ABS steering wheel cover
High-performance electroplating grade ABS applied to automobile grille
PC/ABS is an alloy plastic blended with PC and ABS, and the blend of PC and ABS can combine the excellent properties of PC and ABS.
Advantage:
Heat resistance, toughness, impact strength (especially for high-strength structural parts) and flame retardancy;
Good processability, apparent quality and low density.
The unit cost of materials is reduced, and the viscosity of the solution is reduced.
As an alloy of two amorphous plastics, PC/ABS has the advantages of excellent comprehensive performance and no obvious disadvantages.
Application:
PC/ABS is used in some decorative parts that require certain heat resistance and high impact requirements, such as electroplated door handles, center console decorative panels, etc. Due to its excellent low temperature performance, dimensional stability and excellent adhesion to foam, PC/ABS is also often used in the instrument panel body of high-end models.
PC/ABS applied to central control panel/CD holder
PC/ABS alloy applied to door handle
Polyformaldehyde is a semi-crystalline plastic, and POM is divided into homopolymerization and copolymerization. Homopolymeric POM is a homopolymer of paraformaldehyde or formaldehyde; copolymerized POM is a copolymer of paraformaldehyde and 1,3-dioxolane. Homopolyoxymethylene has high crystallinity, better mechanical strength, rigidity, heat distortion temperature and other indicators than copolymerized polyoxymethylene, lower melting point of polyoxymethylene copolymer, thermal stability, chemical corrosion resistance, flow characteristics, processability and continuous use temperature are better than homopolyoxymethylene formaldehyde.
The end group of POM is hemiacetal (-CH2OH). When the temperature is higher than 100°C, the end group is easy to break. Generally, it needs to be stabilized by end-capping treatment to improve its thermal stability and heat-resistant service temperature.
Advantage:
High wear resistance, specific strength and specific rigidity close to metal, good fatigue resistance.
Shortcoming:
Low temperature resistance, poor flame retardancy, and large shrinkage.
Application:
POM is mainly used in parts with high requirements for creep resistance, fatigue resistance, wear resistance or self-lubricating requirements, such as bumper mounting brackets, opening handles, buckles, sealing internal mechanism parts, glass lifting systems, etc.
Ultra High Viscosity POM for Window Regulator Components
POM applied to speaker grill