What materials are generally chosen for injection molded products in the automotive industry?

What materials are generally chosen for injection molded products in the automotive industry?

There are many kinds of raw materials. The application of automotive plastic injection molded parts is divided into interior parts, exterior parts and functional parts. According to the different use characteristics of famous brand plastics, injection molding products are usually divided into three types: general plastics, engineering plastics and special plastics.
1. General plastics
Generally refers to plastics with large output, good formability, low price and wide application. General-purpose plastics include five major varieties, polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), propylene-butadiene-styrene copolymer (ABS), and thermoplastics.
①PP
Polypropylene, commonly known as pleated glue, is similar to white wax, transparent, light in weight, has good fluidity during injection molding, and has a water absorption rate of less than 0.02%. PP shrinkage rate is 1.0-3.5%.5-2.5mm.
There are two main problems in the wide application of PP in the automotive field: flammability (combustion) and brittleness in low temperature environments. In order to solve these two problems, appropriate additives are added to modify PP in industrial practical applications. Flame retardants are added when it is flammable; in low temperature environments, it is brittle. Other tough materials are mainly used to add rigid particles or elastomers for various modifications and toughening, such as rubber (EPDM), talcum powder (TD), glass fiber (GF), etc. There are many automotive products made of resin from PP, including various instrument panels, door panels, pillar panels, bumpers, water tanks, decorative panels, and the trend of PP automotive applications is increasing.
②PE
Polyethylene is one of the lightest plastics in the processing of injection molding products. It has good water resistance, acid and alkali resistance, organic solvent resistance and excellent electrical insulation. Shrinkage rate 1.5~4.0..0-2.5mm.
As an automotive material, PE has the biggest disadvantage of being easy to burn. The simple method is to add appropriate flame retardants to improve the combustion performance of PE. The automotive products made of PE mainly include fuel tanks, air ducts, front seat decoration covers, air ducts, etc. Assembly (HDPE), left and right ventilation pipe assembly, connecting rod for up and down wind direction blades, left and right foot vent assembly, etc.
③PVC
Commonly used polyvinyl chloride PVC is a multi-component plastic. Due to the different content of each component in the processing of injection molding products, PVC particles with different mechanical properties and different hardness are formed, which are generally divided into two categories: soft PVC particles and hard PVC particles. Shrinkage rate: rigid PVC1.1.5%PVC2-2.3%.5mm.
Polyvinyl chloride is a commonly used plastic raw material in automotive plastic products. PVC automotive plastic products can be seen everywhere, PVC instrument panel skin, PVC plastic steering wheel, PVC plastic liner, PVC plastic car floor materials. This is not only because PVC resin is economical in price, but also has better processing performance and comprehensive mechanical properties.