Today, we are going to talk about automotive plastics, the specific applications of engineering plastics in the automotive field.
The main function of engineering automotive plastics used in automobiles is to make automobiles lighter, so as to achieve the purpose of fuel-saving and high speed. Developed countries regard the amount of plastic used in automobiles as an important indicator of the level of automobile design and manufacturing. The largest single use of automotive plastics in the world is Germany, which accounts for 15% of the overall materials.
In recent years, China’s automobile industry has developed rapidly. At present, the annual output of automobiles exceeds 4 million. According to the forecast of foreign plastic consumption, the annual consumption of modified plastics in the automobile industry is more than 500,000 tons, of which engineering automotive plastics account for a large proportion. The five major engineering automotive plastics performance characteristics are different, and the uses of the automotive plastics in the car are also biased.
Nylon in automotive plastics
Nylon in automotive plastics is mainly used in automobile engines and engine peripheral parts. The main varieties are GFPA6, GFPA66, enhanced flame retardant PA6, and other products.
- Application on peripheral parts of automobile engine as the peripheral parts of the engine are mainly heat-generating and vibrating parts, most of the materials used in the parts are glass fiber reinforced nylon.
This is because nylon has better comprehensive properties. The main properties of nylon modified with glass fiber are greatly improved, such as strength, product accuracy, and dimensional stability.
In addition, nylon has many varieties, is easier to recycle, and is relatively cheap. These factors make nylon an ideal material for engine peripheral components.
The intake manifold is the most typical application of modified nylon in automobiles. In 1990, the German BMW Motor Company first applied the intake manifold made of glass fiber reinforced nylon to a six-cylinder engine;
Then Ford and DuPont of the United States cooperated to apply the intake manifold made of glass fiber reinforced PA66 to the V6 engine. In the future, major automobile companies in the world have followed up and modified nylon intake manifolds that have been widely used.
- Application in automobile engine parts.
Engine heads, engine decorative covers, cylinder head covers, and other parts generally use modified nylon as the preferred material. Compared with metal materials, the cylinder head cover has a 50% weight reduction and a 30% cost reduction. In addition to engine parts, other stressed parts of the car can also use reinforced nylon, such as oil filters, wipers, radiator grilles, etc.
Polyester in automotive plastics
In the field of automobile manufacturing, PBT is widely used in the production of bumpers, carburetor components, fenders, spoilers, spark plug terminal boards, fuel supply system parts, instrument panels, automobile igniters, accelerators, and clutch pedals.
The competition between PBT and enhanced PA, PC, and POM in the automobile manufacturing industry is very fierce. PA is easy to absorb water, and the heat resistance and resistance of PC are not as good as that of PBT. In terms of automotive use, the water absorption resistance of PBT is better than that of PA. Will gradually replace PA.
In the case of high relative humidity and very humid conditions, the plasticity is likely to decrease due to humidity, and the electrical nodes are likely to cause corrosion. Modified PBT can often be used. At 80°C and 90% relative humidity, PBT can still be used normally, and the effect is very good.
GE’s PBT/PC alloy, trade name Xenoy1731, is the most widely used in luxury cars; it has good heat resistance, stress cracking resistance, excellent wear resistance, chemical resistance, high low-temperature impact strength, and easy processing It has good paintability and is mainly used in high-end car bumpers, car bottom plates, panels, and motorcycle guards, etc.
Polyoxymethylene in automotive plastics
The largest potential market for POM is the automotive industry. POM is light in weight, easy to process and shape, low in production cost, and material properties are similar to metals. The wear resistance coefficient of modified POM is very low, and the rigidity is very strong;
It is very suitable for manufacturing automobile pumps, carburetor parts, oil pipes, power valves, universal bearings, motor gears, cranks, handles, dashboards, automobile window lift devices, electric switches, seat belt buckles, etc.
Manufacturing bushings, gears, sliders, and other wear-resistant parts are the strength of modified POM. These parts have less metal abrasion, reduce the amount of lubricating oil, and enhance the service life of the components.
Therefore, it can widely replace copper, zinc, and other metals to produce bearings, gears, tie rods, etc. The auto parts produced by POM are light in weight, low in noise, and easy to form and assemble. Therefore, they are more and more widely used in the automobile manufacturing industry.
Polycarbonate in automotive plastics
Due to the Polycarbonate in automotive plastics its high mechanical properties and good appearance, modified PC is mainly used for exterior parts and interior parts in automobiles. The most widely used are PC/ABS alloy and PC/PBT alloy.
(1) Automobile interior parts PC/ABS alloy is the most suitable material for automobile interior parts. This is because PC/ABS alloy has excellent heat resistance, impact resistance and rigidity, and good processing fluidity.
It is also an ideal material for manufacturing automobile dashboards. The heat distortion temperature of PC/ABS alloy is 110℃～135℃, which can fully meet the heating requirements of cars parked outdoors at noon in the hot summer in tropical countries.
PC/ABS alloy has a good finish and adhesion to the covering film. Therefore, the instrument panel made of PC/ABS alloy does not require surface pretreatment and can be directly sprayed with a soft topcoat or coated with PVC film.
PC/ABS alloy is also used to manufacture automobile parts such as parts around automobile dashboards, antifreeze panels, door handles, undercurrent plates, brackets, steering column sheaths, decorative panels, and air conditioning system accessories.
(2) PC/PBT alloy and PC/PET alloy for automotive exterior parts not only have the high heat resistance and high impact resistance of PC, but also the chemical resistance, wear-resistance, and molding processability of PBT and PET, so they are manufactured Ideal material for automotive exterior parts.
PC/PBT car bumpers can withstand low-temperature impacts below -30℃. When the bumper breaks, it is a ductile fracture and no fragments are generated. Elastomer toughened PC/PBT alloy and PC/PET alloy are more suitable for making car body panels, car side guards, fenders, car door frames, etc. High heat-resistant PC/PBT alloy and PC/PET alloy injection molding exterior parts can be painted without painting.
PC/PET alloy can be used to make automobile exhaust ports and license plate covers. PC/ABS alloy can also be used to make automobile exterior parts, such as automobile wheel covers, reflector shells, tail lamp covers, etc. PC/ABS has good formability and can be used to process large automobile parts, such as automobile fenders.
Polyphenylene ether in automotive plastics
Modified PPO (Polyphenylene ether in automotive plastics) is mainly used in automobiles for parts that require high heat resistance, flame retardancy, electrical properties, impact properties, dimensional stability, and mechanical strength.
For example, PPO/PS alloy is suitable for damp, loaded, high electrical insulation requirements, and good dimensional stability. It is suitable for manufacturing automobile wheel covers, headlight glass grooves, taillight shells, and other parts, and also suitable for manufacturing connection boxes and fuses. Automotive electrical components such as boxes, circuit breaker housings, etc.
PPO/PA alloy has excellent mechanical properties, dimensional stability, oil resistance, electrical insulation, and impact resistance. It can be used to make automobile exterior parts, such as large baffles, cushions, rear spoilers, etc. The future application direction of PPO/PA alloy for engine hoods that require high glass transition temperature.
PPO/PBT alloy has a high heat distortion temperature and is less sensitive to moisture, making it an ideal material for manufacturing automotive exterior panels.
The development direction of the automobile industry is high-end, miniaturization, lightweight, and diversification. The research on replacing steel with plastic in automobile applications has also become very active.
At present, domestic automotive plastics account for an average of 7% of the total materials, and the proportion in Germany is 15%; we need to increase research and development work to achieve the simultaneous development of the design of the accessory structure, the selection of automotive plastics and the industry.