The main function of engineering plastics used in autom […]
The main function of engineering 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 to measure the level of automobile design and manufacturing. In recent years, my country’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 plastics account for a large proportion. The five major engineering plastics The performance characteristics are different, and the uses in the car are also biased.
Nylon is mainly used in automobile engines and engine peripheral parts, the main varieties are GFPA6, GFPA66, reinforced flame retardant PA6 and other products. (1) 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 a 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 six-cylinder engines; later, Ford and DuPont in the United States In cooperation, the intake manifold made of glass fiber reinforced PA66 is applied to the V6 engine. In the future, major automobile companies in the world will follow up, and the modified nylon intake manifold has been widely used. (2) Application in automobile engine parts. Engine heads, engine decorative covers, cylinder head covers and other parts generally use modified nylon as materials. Compared with metal materials, the cylinder head cover is used as an example to reduce the quality by 50% and reduce the cost by 30%. In addition to engine parts, other stressed parts of the car can also use reinforced nylon, such as oil filters, wipers, radiator grilles, etc.
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 ignitions, 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 is 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 widely used in cars; it has good heat resistance, stress crack resistance, excellent wear resistance, chemical resistance, high low-temperature impact strength, easy processing and coating Good performance, mainly used in car bumpers, car floor panels, panels and motorcycle guards, etc.
POM is light in weight, easy to process and shape, low in production cost, and material properties are similar to metals. Modified POM has a low wear resistance coefficient and strong rigidity; it is very suitable for manufacturing automobile pumps, vaporizer parts, oil pipes, power valves, universal bearings, motor gears, cranks, handles, dashboards, and automobile window lift devices. , Electric switch, seat belt buckle, etc. Manufacturing bushings, gears, sliders and other wear-resistant parts are the strengths of modified POM. These parts have less metal wear, reduce the amount of lubricating oil, and enhance the service life of the parts; therefore, it can widely replace copper, zinc and other metals to produce bearings , Gears, levers, 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.
Modified PC is mainly used for exterior parts and interior parts in automobiles because of its high mechanical properties and good appearance. PC/ABS alloys and PC/PBT alloys are widely used.
(1) Automobile interior parts PC/ABS alloy is a 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 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 soft topcoat or coated with PVC film.
PC/ABS alloy is also used to manufacture auto parts such as automotive instrument panel surrounding parts, antifreeze plates, door handles, undercurrent plates, brackets, steering column sheaths, decorative panels, air-conditioning system accessories, etc.
(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 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.
Five, polyphenylene ether
Modified PPO 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 automotive 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. It is an ideal material for manufacturing automobile outer panels.
The development direction of the automobile industry is miniaturization, light weight 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 plastic materials and the industry.