Automotive plastics refer to plastic raw materials specifically used for automobile manufacturing.

Background

Automotive plastics are widely used in the automotive parts processing and manufacturing industry. Hechuan has introduced cutting-edge formula dissection technology to provide automobile manufacturers with a complete set of product formula improvement technology; with the development of lightweight automobiles and the increase in automobile production, China has become the world's largest automobile production and consumption country, and will continue to develop at a high speed. In the past 30 years, the use of automotive plastics in the world has been increasing. The average amount of plastics used in each car has increased from 50 to 60 kg in the early 1970s to about 150 kg at present, and the growth is still continuing. The amount of plastics used in Chinese cars is generally less than 10% of the car's own weight, which is still a big gap compared with the proportion of more than 20% of automotive plastics used in Europe, the United States, and 13 other countries. At present, China's automotive modified plastics industry is in a growth period. It is estimated that by 2015, China's automobile production will reach 32 million vehicles. Calculated based on an average of 150 kg of plastics per car, the total amount will reach 4.8 million tons. The types of plastics used in China's automobiles are arranged in order of usage: PP, PVC, PUR, unsaturated resin, ABS, PE, PA, PC, etc., most of which are modified plastics.

There are many plastic parts in cars. The main goal of plasticization of automobile parts was to make the interior of the car softer and make passengers feel safe and comfortable. Since the oil crisis in the early 1970s, in order to save energy, the requirements for lightweight and rust prevention have been put forward for automobiles. Since then, the plasticization of automobile parts has developed rapidly. Especially in recent years, automobile parts have been developing towards light weight, high speed, safety and energy saving, comfort, multi-function, low cost and long life, and various new plastics are ideal materials that meet this development direction.

Plastics for automobiles

The commonly used plastics in automobiles are PVC, ABS, PP, PE, PMMA, POM, PA, FRP, PF, PUR, etc. The commonly used plastic materials are as follows:

1) PC/AB S alloy is used in interior parts, instrument panels, instrument panel surrounding parts, antifreeze plates, door handles, underflow plates, brackets, steering column covers, decorative panels, air conditioning system accessories, automobile wheel covers, mirror housings, taillight covers, fenders, etc.;

2) PC/PBT alloy and PC/PET alloy are used in exterior parts, automobile body panels, automobile side guards, fenders, automobile door frames, etc.

3) GFPA6, GFPA66, and enhanced flame-retardant PA6 are used in automobile engines and engine peripheral parts, engine covers, engine decorative covers, cylinder head covers, oil filters, wipers, radiator grilles, etc.

4) PBT is used in bumpers, carburetor components, fenders, spoilers, Spark plug terminal boards, fuel supply system parts, instrument panels, car ignition, accelerator and clutch pedals, etc.

5) POM is used in automotive pumps, carburetor parts, oil pipelines, power valves, universal joint bearings, motor gears, cranks, handles, dashboards, car window lifts, electric switches, seat belt buckles, etc.

6) PPE/PS alloys are used in automotive wheel covers, headlight glass grooves, taillight shells and other parts; automotive electrical components such as connection boxes, fuse boxes, and circuit breaker shells.

7) PPE/PA alloys are used in external parts such as large baffles, cushions, and rear spoilers

Automotive interior materials

Plastic products and their composite materials are the most important Lightweight materials for automobiles can not only reduce the weight of parts by about 40%, but also reduce the procurement cost by about 40%. Therefore, the interior parts of automobiles produced by foreign automobile companies in China have basically been plasticized. The application of automobile plastic products in automobile interior parts is mainly concentrated in the instrument panel, the interior ceiling, the door pillar decorative panels and the sound insulation facilities in the car. Instrument panel

The instrument panel used in automobiles can be divided into hard instrument panel and soft instrument panel. Hard instrument panel is generally used in light and small trucks and is formed by one-time injection molding. This instrument panel is large in size and has no skin. The surface quality requirements are very high, and high temperature resistance and rigidity are required. The material can be modified, PPO, ABS resin, filled PP, etc. The soft instrument panel consists of three parts: skin, skeleton, and buffer material. General-grade cars use PVC/ABS sheet vacuum forming instrument panel skin, such as FAW Jetta and Shanghai Santana cars; medium and high-end cars use powder PVC slush forming instrument panel skin, such as FAW Audi and Xiaohongqi cars. The skeleton materials include iron plate (such as Audi and Xiaohongqi), cardboard (such as Jetta and Santana), ABS, modified PP, etc. In order to facilitate recycling, the dashboard composed of thermoplastic polyolefin skin (TPO), modified polypropylene skeleton, and polypropylene foam material is being developed. At the same time, with the installation of airbags on cars, soft dashboards have lost their safety requirements. Therefore, as long as the appearance quality is solved, it is completely feasible to use low-cost hard dashboards.

Seat

Currently, the seat cushion material is basically made of soft high-elastic polyurethane foam plastic, and the skeleton is made of metal material. In addition to the cushion pad, the seat skeleton of the all-plastic seat being developed abroad also uses long glass fiber reinforced polypropylene material or 30% glass fiber reinforced PA6, which reduces the weight by more than 40% and reduces the cost by 15%.

Door inner panel

The structure of the door inner panel is basically similar to that of the dashboard, consisting of a skeleton, foam material and skin. The inner door panels are generally made of hard fiberboard or PP wood powder plastic board as the base material, and then laminated or compounded with polyurethane lining; and PVC film or non-woven fabric. Modified PP or ABS is also used to make the inner door panel skeleton, and then compounded with soft decorative materials to form the integral inner door panel. Taking the Red Flag sedan and Audi sedan as examples, the skeleton part of the inner door panel is injection molded by ABS material, and then the knitted polyester skin lined with PU foam material is laminated on the skeleton by vacuum forming to form a whole. Some trucks even use inner door panels with a layer of PVC artificial leather directly attached.

Ceiling

The inner car ceiling is a composite laminated product with the most material varieties and patterns among interior products. In addition to its decorative function, it also plays special roles such as heat insulation, sound insulation, and sound absorption. The types of ceilings can be divided into formed ceilings (the formed ceiling is fixed by inlay bonding), pasted ceilings (the foam pad with skin is directly pasted to the inside of the roof) and suspended ceilings, of which formed ceilings account for more than 70%, and the pasted type is often used for the truck cab and van ceilings.

The formed ceiling is composed of a substrate and a skin. The substrate requires the characteristics of light weight, high rigidity, dimensional stability, and easy forming. For this reason, "thermoplastic" PU foam sheet, PP foam sheet, glass fiber, corrugated paper, honeycomb plastic belt, etc. are generally used. The skin material can be fabric, non-woven fabric, PVC, etc. The Chinese car ceiling is generally formed by laminating "thermoplastic" PU foam sheet, glass fiber, and non-woven polyester cloth.

Carpet

The carpet material must be crisp, soundproof, and comfortable, and no relaxation or wrinkles are allowed, so most of them are made of synthetic fiber needle felt with a rubber base or PVC low foam.

Others

Others such as door pillar covers, glove boxes, glove boxes, air conditioning related shells and various ducts and air guide grilles are mostly made of ABS and polyolefin plastics.

Automobile exterior materials

Currently, the application of plastic products in automotive exterior parts is mainly concentrated in bumpers, radiator grilles, windshields, and bodywork:

Bumpers

Among the plasticization of automotive exterior parts, bumpers are one of the most successful parts in plasticization. Currently, the plastic bumpers used in cars are roughly divided into two categories, thermosetting PUR formed by RIM method and elastomer modified polypropylene. Almost all Chinese automotive plastic bumpers use elastomer blended modified PP materials, while most of the bumpers in the United States use RIM molding method to produce bumpers, while most of Europe uses coated PP bumpers and PC/PBT (polybutylene terephthalate) alloy bumpers, and some Japanese luxury cars use RIM. However, most of the bumpers are still mainly modified PP with lower material costs.

Radiator grille

The grille is an opening part set up for cooling the engine. It is located in the most conspicuous place of the car body and is an important part that shows the style of a car. Therefore, automobile manufacturers attach great importance to the shape design and material selection of the grille. The materials used for the radiator grille are ABS, PC, PP, and PET (polyethylene terephthalate). Considering the electroplating and painting aspects, ABS is used to make the car glossy and three-dimensional. PP can also be used. At present, the grilles on cars generally use ABS or ABS/PC injection molding, surface electroplating or painting. For example, the grille of the Xiaohongqi car is ABS/PC surface spray painting.

The grille also uses ASA (acrylonitrile-styrene-acrylate copolymer) material with good weather resistance. After injection molding, the surface of the product can be unpainted, but its surface is not as good as the painted product. The cost of the grille without a painted surface can be reduced by 50%. The recently appeared grille with metal chromium sputtered on the surface of polyester elastomer is very popular.

Wheel covers

Plastic wheel covers are divided into full cover type and half cover type. Recently, the requirements for automobile aerodynamics have been improved, and there is a trend of increasing full cover wheel covers. The plastic materials used in wheel covers include ABS, PA, PC, ABS, PPO/PA, etc. Wing lining, engine fender

The lining of the car fender is generally made of low temperature resistant and high toughness polypropylene. The fender lining on Audi and Jetta cars has been domestically produced. The engine fender on the CA1092 car was originally composed of 4 steel plates. After changing to polypropylene plastic, the cost and quality were reduced, and the anti-corrosion performance was improved.

Lights

Headlights

Considering the transparency, heat resistance, impact resistance and formability of the headlight glass, most cars use PC coated with a hard film on the surface, thereby further improving the scratch resistance and weather resistance. In order to meet the heat resistance surface treatment requirements, the headlight reflector shell generally uses PPS and PC/PBT.

With the emergence of discharge lamps, other plastics with lower heat resistance may be used. The rear combination indicator lampshade material is PMMA, and the lamp shell is filler-modified PP, which are joined with hot-melt adhesive.

With the development of vibration welding technology, heat-resistant ABS materials are used for lamp shells, so that the lamp shell and lampshade can be vibration-welded, which is also convenient for material recycling.

Other body parts

Door handles generally use POM, and electroplated parts use PC/ABS. Locks generally use POM with good rigidity. The support mechanism and hand crank of the glass lifter are made of POM. The rod of the wiper mechanism can be made of PBT (polybutylene terephthalate), the ball bowl can be made of POM, and the small gear on the micromotor can be made of POM.

Structural parts, functional parts

Valve chamber cover

Plastic cover is light in weight and low in noise, and is gradually replacing steel stamping and aluminum die-casting cylinder cover. In Europe and Japan, glass fiber reinforced nylon is selected, and the United States tends to prefer thermosetting plastics. Other optional materials include PPS (polyphenylene sulfide), thermosetting polyester BMC (bulk molding compound), SMC (sheet molding compound) and phenolic plastics.

Cooling fan, wind shield

Made of reinforced polypropylene material, most Chinese models have adopted plastic products.

Fuel tank

Compared with traditional metal fuel tanks, plastic fuel tanks have low cost, light weight, good economic benefits and better safety. It is mainly made of ultra-high molecular weight polyethylene.

Radiator water chamber

Automobile radiators are usually made of copper alloy. In recent years, aluminum radiators have increased, but welding is difficult, so the radiator water chamber material has been transformed into plastic that is easy to join. The main material is glass fiber reinforced nylon 66, which has heat resistance, chemical resistance and dimensional stability that meet the requirements, and the mass is reduced by 30%.

Water pump, oil pump housing

The engine's water pump and oil pump housing are mostly made of cast iron or aluminum. Currently, phenolic resin materials are used. Under high temperature and high load conditions of the engine, they can maintain good dimensional stability, light weight, low noise and low cost.

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