1.1 rubber hose for automobile
In 2008, there were more than 20 manufacturers of silicone rubber tubes for automobiles in China. However, on the whole, the production enterprises were generally small in scale, scattered in distribution, weak in technical strength, relatively backward in production technology and equipment, and slow in the development of new products. In terms of production capacity, the supply of rubber hose for ordinary automobile is greater than the demand, while the hose required by high-grade car is far from meeting the market demand. At present, the localization rate of rubber hose is less than 40% and that of high-grade cars is only 5%. Therefore, the automobile hose industry should keep up with the international trend in the future. Only by speeding up the development of high-performance silicone products for automobiles can we meet the development needs of the automobile industry.

1.1.1 brake hose
Due to the appearance of the free car, the increase of the working environment temperature of the brake fluid and the use of the high boiling point brake fluid, at present, the internal rubber layer of the brake hose tends to use EPDM instead of styrene butadiene rubber. In foreign countries, the internal and external rubber layer of the brake hose is mostly EPDM rubber, and the reinforcement layer uses polyester, polyglycol or rayon fiber. The inner rubber layer can be pressure resistant polyamide, and the outer rubber layer is chlorosulfonated polyethylene.

1.1.2 fuel hose
Due to the use of unleaded gasoline and its development towards high oxidation value, the corrosivity of fuel to rubber increases. Therefore, the inner layer of fuel hose must have good fuel resistance. In order to reduce the fuel permeability and further improve the heat resistance of the rubber, fluororubber, Chloroether rubber or acrylate rubber have been developed to replace nitrile rubber in the inner rubber layer.

1.1.3 power steering hose
The development of automobile has put forward the requirements of high heat resistance and high durability for rubber hose. The inner rubber layer should have good oil resistance, and the outer rubber layer should have the characteristics of wear resistance, heat resistance and weather resistance. At present, the inner and outer layers of the hose have been transformed from nitrile rubber and chloroprene rubber to hydrogenated nitrile rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber and acrylate rubber. The reinforced layer is mainly nylon 66.

1.1.4 radiator hose
With the development of automobile to the direction of energy saving and low pollution, the engine temperature has increased by 15 ~ 50 ℃ in recent years. Therefore, the heat sink hose produced by sulfur vulcanization system is gradually replaced by the products produced by peroxide system, and the main material used is EPDM.

1.1.5 turbocharger hose
The main requirement of the hose is to have good heat resistance. In foreign countries, all rubber structure is adopted for turbocharged hose, that is, the inner rubber layer is composed of fluororubber and silicone rubber with good heat resistance, the reinforcing layer is composed of aramid fiber knitting with high strength, and the outer rubber layer is made of silicone rubber.

1.1.6 air conditioning hose
At present, with the application of the new environmental refrigerant R134a, the structure and material of air conditioning hose have changed greatly. The structure of resin, chlorinated butyl rubber and ethylene propylene diene monomer (EPDM) in the inner rubber layer becomes the best combination, and its application effect is good.

1.2 automobile oil seal
Oil seal is a kind of high-tech precision rubber parts. After more than ten years of development, China’s annual demand for oil seals has exceeded 100 billion pieces, including more than 100 million pieces of automobile oil seals for automobile main engine plants, and more than 300 production enterprises of different sizes, including more than 10 enterprises with annual production capacity of more than 30 million pieces and product varieties There are more than 3000 kinds of products, and 30% of the enterprises have different quantities of exports. The development of automobile industry provides a broad market and good opportunity for the development of oil seal. Through technology introduction and product structure adjustment, China’s oil seal industry has accelerated the application of new technologies and the development of new products, and the performance, quality and variety of products have been greatly improved, especially the automobile engine, gearbox, valve oil seal, fluororubber, and so on Acrylic rubber, hydrogenated nitrile rubber, polytetrafluoroethylene oil seal and composite special oil seal have made obvious progress in manufacturing technology. The key point is that in the future, domestic oil seal manufacturers should focus on oil seal fluid dynamics and develop high-performance products with independent intellectual property rights. In the future, the development trend of oil seal is composite oil seal, aluminum skeleton bonded fluororubber oil seal made by injection vulcanization process, PTFE sheet on oil seal lip and glass added to PTFE Glass fiber, graphite, molybdenum disulfide, etc. can achieve better results.

1.3 automobile sealing strip
At present, there are more than 60 enterprises producing automobile rubber sealing strips in China, and more than 40 advanced extrusion production lines for automobile rubber sealing strips have been introduced. The annual production capacity is about 170 million meters, and the actual output is about 100 million meters. With the rapid development of automobile industry, there are more and more new materials used in automobile sealing strip, especially the advantages of thermoplastic elastomer used as automobile sealing strip. The main thermoplastic elastomer materials used in automobile sealing strip are polyolefin thermoplastic elastomer (TPV), which has good wear resistance and low friction coefficient. It can be used not only as extrusion material for automobile glass guide groove sealing strip, but also as corner material for automobile sealing strip. In addition, the water foaming sponge TPV has been successfully developed in foreign countries, and has been widely used in automobile rubber sealing strip, which has become a new trend to replace sponge rubber in making automobile sealing strip. In addition, the coloring process of TPV is simple and convenient, which is usually used as the exterior decoration material of automobile rubber sealing strip

1.4 automobile transmission belt
There are two main types of automobile transmission belt: V-belt and synchronous gear belt. The production of transmission belts for cars in China, especially synchronous gear belts, started relatively late. There is still a certain gap in product quality and performance compared with foreign similar products. In 2006, the output of V-belt for automobile in China was about 600 million meters, and the output of synchronous belt was about 18.9 million. In foreign countries, chloroprene rubber and hydrogenated nitrile rubber are used as the main materials of V-belt, and polyester cord and aramid cord are used as the skeleton materials; while chloroprene rubber is mainly used in China, and hydrogenated nitrile rubber is rarely used, while rayon and glass fiber are mainly used as skeleton materials. In China, chlorosulfonated polyethylene and hydrogenated nitrile rubber are used as the main materials of automobile synchronous belt, and glass fiber is used as the skeleton material, while hydrogenated nitrile rubber isobutyric acid composite material is mainly used in foreign countries, and the skeleton material is aramid cord. Therefore, in the future, the manufacturing of domestic transmission belt should be transited from traditional chloroprene rubber and chlorosulfonated polyethylene rubber to hydrogenated nitrile rubber as soon as possible. Meanwhile, the skeleton material should be based on domestic development and be transferred to aramid cord and polyester cord as soon as possible.

1.5 automobile damping rubber products
At present, there are hundreds of manufacturers of rubber products for automobile vibration damping in China. The products mainly include rubber spring, rubber air spring, frame beam, engine suspension damper, torsional vibration damper, etc. It plays an important role in limiting vehicle emissions, reducing noise and improving ride comfort and safety. With the rapid development of automobile industry, especially the requirements for safety, comfort and easy operation of driving, the consumption of silicone products for automobile vibration damping is increasing year by year. In 2008, the domestic market demand of automobile damping rubber products is about 150 million. Moreover, the production of high-end cars is increasing, and the market demand of automobile damping rubber products is growing faster Therefore, the demand for materials is also diversified. However, it needs to be selected according to the different parts of the products. Considering the fatigue and creep resistance, natural rubber should be selected. If the heat resistance is to be improved, styrene butadiene rubber should be selected; if the dynamic heat generation is small, cis-1,4-butadiene rubber can be selected; if the rubber vibration damping products are in contact with various oil media, then nitrile rubber is selected; due to the emission standard of automobile exhaust gas, the selection of butadiene rubber is very important More stringent restrictions are permitted, resulting in higher engine and exhaust pipe temperatures. The rubber used in these areas requires EPDM with high heat resistance. The future development direction of shock absorber products for automobiles in China is standardization and serialization, and the emphasis should be placed on the hydraulic and torsional shock absorbers which have been successfully applied in foreign countries. The development of rubber damping materials should further improve its heat resistance and develop new elastomer materials with low dynamic ratio and high damping.

1.6 other rubber products
In addition to the above automotive rubber products, other main varieties are brake film, leather cup and dust cover. The future development should focus on the use of fluorosilicone rubber, polyester fabric as the framework material for car fuel supply pressure regulator diaphragm; the use of chlorinated polyethylene to make automotive diaphragm. As the material of dust cover, the most important requirement is good weather resistance. Chloroprene rubber is usually used in constant velocity direction joint, but with the improvement of heat resistance, the application of polyolefin thermoplastic elastomer increases gradually. In Europe and America, most cars use polyolefin thermoplastic elastomer to make dust cover. This kind of material can not only meet the requirements of weather resistance, oil resistance and heat resistance, but also realize the lightweight of automobile.

2: Technical requirements for materials of automotive rubber products
Although some natural rubber and general synthetic rubber are used in automobile rubber products (excluding tires), special rubber with better performance is used in most occasions. Foreign automobile rubber products manufacturers are using ACM, HNBR, FKM, Si, CHC, chlorosulfonated polyethylene and other special rubbers in a large number. At the same time, they are constantly developing and applying special rubber with unique performance. Dow Corning’s fluorosilicone rubber with grades of silastic 4-9040, 4-9060 and 4-9080 has excellent heat resistance, fuel resistance and solvent resistance. It is very suitable for the manufacture of automotive rubber hose and silicone sealing products. Santaprene rubber of AES company has been used in sealing products of Ford, Volkswagen, Toyota and Benz automobile companies. EPDM / silicone modified rubber products developed abroad are superior to silicone rubber in heat resistance, weather resistance and compression set performance. They can be vulcanized with sulfur or peroxide, and are suitable for various molding methods. Therefore, EPDM / silicone modified rubber products can be used in situations where silicone rubber or ethylene propylene rubber cannot adapt (automobile damping materials, etc.). At present, the main materials of automobile rubber parts in our country are mainly traditional NR, SBR, Cr, NBR and EPDM, while ACM, FKM, Si, HNBR, TPE and other special new rubbers are only used in a small amount. The main reason is that the output of special rubber products in China is very small, the production has not formed scale and seriation, and many varieties need to be imported from abroad To a certain extent, it limits and affects the development of automobile rubber products to high performance and specialization. In the future, with the rapid development of automobile industry, higher requirements are put forward for the quality, performance and quantity of automobile rubber products. Therefore, in a sense, it will stimulate the development of special rubber industry in China, so as to promote the development of new materials and new products.