The rapid development of China's automobile industry has promoted the development of other related supporting industries in my country, especially the rubber industry. In the past few years, automotive rubber products have developed into a unique and specialized product industry. Automobile rubber products are an indispensable and important component of automobile accessories. There are about 100-200 kinds of rubber products installed on each car, and about 200-500 rubber accessories are used. Except for tires, it varies with different specifications of cars. The consumption of rubber materials is about 15-60 kg, and automobile rubber products (excluding tires) account for about 6% of the total cost of automobiles. There are about 1,000 varieties of non-tire rubber products for the automotive industry, with more than 8,000 specifications. According to statistics, the automobile industry occupies more than 70% of the global annual consumption of raw rubber, of which tires occupy 60%, and automobile rubber products and accessories occupy 40%.

High speed, safety, comfort, energy saving and environmental protection are the goals pursued by contemporary automobiles. With the development of automobile modernization, the requirements for automobile rubber products are becoming stricter and more demanding. Not only are rubber materials with various special properties required to meet the new technical requirements of automobiles, but also rubber materials are required to have higher physical and mechanical properties, such as It is resistant to aging, high and low temperature, resistant to new fuels, excellent dynamic fatigue performance, and durable service life. In fact, every high performance of a modern automobile has to rely on the technological advancement of rubber products to provide guarantee. The performance and quality of automobile rubber products play an extremely critical role in improving the quality of the entire automobile. It is worth pointing out that the role played by rubber products is always an accessory, but this accessory always controls the technological progress and technical level of the host. Therefore, it can be said that the technology and quality of automobile rubber products can basically reflect the technical level of the entire automobile.

1. Classification of automobile rubber products and its role in automobiles

Rubber tires are called the two legs of a car, and the important role of tires in a car is self-evident. Tires are the rubber products that consume the largest amount of rubber in the rubber industry. Therefore, in the rubber industry, tires are often separated from rubber products into a special variety. Among auto parts, rubber tires are a special kind of parts.

Automobile rubber products can be divided into seven categories: tires, sealing products, shock absorption products, safety products, tape products, hose products and other products such as wipers, mudguards, adhesives, sealants and interior products.

1.1 Tire

Car tires play the role of carrying the weight of the car, the entire weight of the people and the goods on the car, and also play the role of making the car forward, reverse, turn and brake. The safety, comfort, and driving performance of automobiles depend to a large extent on the high performance and high quality of tires.

Rubber tires have a history of 160 years. As early as 1845, the British R. W. Thomso put a rubber tube on the wooden wheel, thereby reducing the rolling resistance of the wheel and reducing the vibration, but this early rubber tire was very popular at the time. Of course, this should be attributed to the excellent properties of rubber materials. Until 1888, the British J. B. Dunlop invented the pneumatic tire. In the next one hundred years, with the development of the automobile industry, rubber tires have undergone several generations of product development, renewal and progress. The tire frame materials have developed from cotton cord, rayon to nylon cord bias tires. To today’s steel radial tires.

Mankind invented pneumatic tires, which effectively promoted the development of automobiles. Because the pneumatic tire has excellent cushioning and shock absorption performance, it can significantly reduce vibration, which makes the car operation safer and more comfortable to ride. At the same time, it can greatly increase the driving speed of the car. With the continuous progress of rubber materials, formulation technology, manufacturing equipment and manufacturing processes, the safety and life durability of automobile tires have been greatly improved. For example, in 1900, the mileage of each tire was only 800km; by 1978, the mileage of each tire had reached 60,000 km; in the 21st century, the mileage of each tire was no less than 140,000 km, even 20 Million km. With the rapid construction and use of expressways, the speed of vehicles has increased dramatically, from tens of km/h to 100 km/h, 140 km/h or even 200 km/h.

1.2 Sealed products

Sealing products are divided into three categories: O-rings, skeleton oil seals and sealing strips. O-rings and skeleton oil seals are installed on the engine, gearbox, car main shaft and hydraulic pneumatic transmission system to prevent lubricating oil, hydraulic oil and other liquid leakage or gas leakage, ensure the normal operation of each component system, and prevent external sand particles Dust and impurities enter the system and affect the normal operation of the machine. O-ring seals and skeleton oil seals are mainly used for the sealing of rotating shafts or reciprocating shafts. According to the structure, the skeleton oil seal can be divided into inner skeleton oil seal, outer skeleton oil seal, semi-exposed skeleton oil seal, sealing lip oil seal, oil seal with auxiliary lip and combined oil seal, etc.; according to the installation position in the car, it can be divided into crankshaft front oil seal and crankshaft rear oil seal. , Gearbox oil seals, cam box oil seals, wheel housing oil seals, axle shaft oil seals, pneumatic guide rod oil seals and shock absorber oil seals, etc. Sealing strips are mainly used in automobile doors and windows, luggage compartments, engine hoods and other parts to play the role of sealing, wind blocking, rain blocking, shock absorption and sound insulation. According to the structure, it can be divided into pure rubber sealing strip (also can be divided into sponge rubber and dense rubber) and composite sealing strip (rubber/metal frame composite strip, two or more rubber composite strips and rubber-plastic composite strips).

1.3 Shock absorption products

Rubber damping products are mainly installed in the engine, body, air conditioner and vehicle suspension system. It is mainly used to reduce the vibration and noise when the car is running, and to improve the stability, safety and comfort of the car's handling. With the continuous improvement of the comprehensive performance of modern automobiles, higher and higher requirements are put forward on the performance and quality of rubber shock-absorbing products. The main requirement is that shock-absorbing products have excellent shock-absorbing damping performance, anti-dynamic fatigue performance and long life durability. Automobile rubber damping products mainly include air springs, engine front and rear suspension pads, flexible couplings, and various shapes of rubber bushes, gaskets, etc. Special shock absorbers with excellent performance are also installed in each tire support on premium cars.

1.4 safety products

Automotive rubber safety products play a role in braking reliability, driving safety and personal safety in automobiles. Safety products mainly include brake film (diaphragm), leather cups, brake pads, airbags and bumpers.

The brake film and the leather cup are directly related to the safety of the car. When the car encounters an accident during the driving, the car will be quickly decelerated or even stopped to ensure the safety of the vehicle and personnel. Airbags are rubber products that provide safety for vehicle personnel when a vehicle is hit by an accident. The bumper is used to reduce the impact force when the car is in a collision.

1.5 Hose products

Hose products are used in the three main parts of the chassis, engine and body. They are used in the seven systems of oil, gas, drive, control, braking, cooling and heating, and play the role of oil supply, gas supply, water supply and power transmission. The types of hoses include fuel hoses, water delivery hoses, brake hoses, vacuum hoses, air conditioning hoses, radiator hoses, power steering hoses and special-shaped branch hoses.

1.6 tape products

Tape products are mainly used to transfer torque power and speed in automobiles, and transfer power from the power source engine to the place where power is needed. Installed in cooling fans, cooling water pumps, brake compressors, booster pumps, air conditioning systems, and steering systems. Tape products are divided into V-belt (also divided into ordinary V-belt and V-ribbed belt) and synchronous belt (toothed belt). According to the structure, V-belts are divided into cutting belts and cloth-covered belts. The V-belt is characterized by high speed and large transmission power. Synchronous toothed belts are used for gas ignition of automobile engines, and their use conditions are high speed, high transmission power and high temperature.

1.7 Other products

This type of rubber products include automobile rubber sheets (in-vehicle rubber sheets and fenders), automobile interior trims and adhesives, sealants, wiper strips, etc. Floor glue is used to lay the ground in the car, anti-vibration and anti-skid. The wiper strip is used to wipe off the rain and snow on the windshield in rainy and snowy weather, to ensure the driver's sight, normal operation and normal driving of the vehicle. Adhesives are used for the bonding of automotive interior materials and the protection of the bottom of the car.

2 The status quo and development trend of my country's automotive rubber products

2.1 Tires

In recent years, as cars have gradually entered the family, it has stimulated the rapid development of my country's automobile industry and promoted the development of the automobile supporting industry and the rubber product industry. Obviously, rubber tires are the first to bear the brunt.

Due to the high speed of automobiles, the rubber tire products are transformed from bias tires to radial tires. Radial tires are the development direction of my country's tire industry and are the key models supported by the state. Since 2001, domestic tire factories in my country have been carrying out infrastructure and technological transformation around radial tires. The development speed is very fast and very successful. In 2004, my country’s tire production reached 210 million, of which 109 million radial tires, with a radialization rate of 52%. In addition to satisfying the domestic market demand, nearly one-third of the output of tires has entered the international market. In 2005, my country’s tire output reached 230 million, of which 130 million were radial tires, and the radialization rate reached 56%. It is predicted that by 2010, my country’s tire production will reach 300 million, of which 210 million radial tires, with a radialization rate of 70%. Radial tires will account for about 85% of car tires. By 2015, we will strive to achieve 95% of car tires radialization rate.

In 2004, my country’s tires consumed 2.2 million tons of raw rubber. In 2005, rubber consumption reached 2.43 million tons, an increase of 10.5%. Among them, natural rubber accounts for about 56.6%, synthetic rubber accounts for about 43.4%. Synthetic rubbers are mainly styrene-butadiene rubber and butadiene rubber (tires), as well as butyl rubber and chlorobutyl rubber (inner tubes). Due to the limited natural rubber resources in my country, the future development direction should appropriately increase the proportion of synthetic rubber used. The main added synthetic rubbers are styrene butadiene rubber and butadiene rubber. However, because the comprehensive properties of these two synthetic rubbers are not comparable to those of natural rubber, excessively increasing the application ratio of these two synthetic rubbers will reduce the quality of tires. In the future, the physical properties of these two kinds of rubbers should be improved or new varieties should be developed.

2.2 Sealing products

In recent years, through the introduction of foreign advanced technology, equipment and technological transformation in my country’s automobile rubber products industry, a number of key enterprises with larger production scales and higher professional levels have emerged, gradually forming a relatively complete industrial system that can basically satisfy And meet the needs of my country's automobile industry.

At present, there are more than 30 skeleton oil seal plants with a certain scale and level in China, with a total production capacity of about 200 million pieces. At present, domestically, it can produce automobile-specific skeleton oil seals with various structures including internal and external skeleton oil seals, pressure-resistant oil seals, and main lip with oil-return line fluid dynamic oil seals, which can meet the needs of the domestic automobile market. However, due to the high speed of automobiles and the addition of fuel additives, the operating temperature, medium resistance and accuracy of oil seals have been improved day by day. For example, the linear speed of the rear oil seal lip of some car crankshafts can reach 200 m/s, and the lip temperature can reach 250°C. The structure and material of the original oil seal can no longer meet the requirements of use. Fluorosilicone rubber, acrylic rubber and fluorine rubber are commonly used in foreign automobile engine oil seals. The NBR/PTFE composite oil seal can make the life of the oil seal reach 4000-4500h, that is, the mileage can reach 130,000 km to 180,000 km.

my country's automobile oil seals are still dominated by nitrile rubber. Although a few manufacturers can produce fluoroelastomer and acrylic oil seals, the output and quality cannot keep up with the needs of the automobile industry, and their service life is less than 100,000 km. Oil seals for key parts of high-end cars, such as crankshaft rear oil seals and automobile guide rod oil seals, still rely on imported parts, and the localization rate is very low. For the skeleton oil seal, further improving the heat resistance, dynamic fatigue resistance and compression set resistance of the rubber compound, improving the level of tooling and automation, and improving the accuracy of mold processing are all future tasks. The main material of the oil seal will be widely used in fluorosilicone rubber, chloroether rubber, hydrogenated nitrile rubber and acrylic rubber.

There are more than 60 manufacturers of sealing strips in my country, with 49 production lines for various automobile sealing strips, with a total annual production capacity of 200 million meters.

Sealing strip is one of the fastest-growing industries in my country's rubber products in recent years. Regardless of the output, output value or profit, there has been a substantial increase, and a professional system has basically been formed. The production plants have introduced the production technology, equipment and testing instruments of the Italian Saya Seals Company. The technology and product quality are equivalent to the international level in the 1990s. They can design and develop their own products to basically meet the needs of the domestic car industry. The rubber varieties are basically EPDM rubber. The future development direction will use TPE as the sealing tape, TPV as the glass guide groove, and adopt the new technology of multi-face flocking and extrusion laminating.

2.3 Shock absorption products

my country has more than 20 large-scale rubber shock-absorbing products factories with a production capacity of about 70 million pieces, which can basically meet the needs of domestic automobile production and maintenance and replacement.

At present, advanced foreign countries have successfully developed a new generation of rubber shock absorbers such as liquid-sealed shock absorbers, electronically controlled shock absorbers, and torsion shock absorbers. Such products are still in the development stage in China. my country's automobile shock-absorbing products still mainly use natural rubber, and the combination of natural rubber and butadiene rubber or butadiene rubber. The development direction of materials should be ethylene propylene diene rubber, butyl rubber and other rubbers with good heat resistance and excellent damping properties. The development of new-type shock-absorbing materials that are more heat-resistant and resistant to dynamic fatigue and the development of liquid-sealed shock absorbers are research topics that my country should invest more in in the future.

2.4 Safety products

There are more than 30 factories producing brake coatings (diaphragms) and brake cups for automobiles in my country. After years of transformation, the product performance basically meets the requirements of the automobile industry. The service life of domestically produced high-strength rubber diaphragms has reached the technical mark of 1 million times. The membrane production capacity is 35 million pieces, and the diaphragm production capacity is 15 million pieces. The main raw rubber used is natural rubber or a combination of natural rubber and synthetic rubber. In the future, high-strength rubber diaphragms such as EPDM rubber and thermoplastic elastomer TPE should be further developed and applied.

my country’s airbag production has just started, with only 6-7 manufacturers, with a total production capacity of about 200,000 sets/year. The National Automobile Safety Law stipulates that cars with a total weight of less than 2.5 tons (M1 category) must undergo a crash test before being listed. All cars in the future must meet the standards and must be equipped with safety capsules. Airbags are generally made of nylon and made of neoprene. Looking forward to the next development direction is the use of thermoplastic elastomers to manufacture airbags.

2.5 Hose products

Automotive hoses have grown at a rate of about 25% in recent years. There are more than 20 domestic automotive hose plants of a certain scale, with a total production capacity of 200 million standard meters. Mainly braided hoses and winding hoses, the proportion of resin composite hoses including brake hoses and cooling water hoses is increasing; short fiber hoses are valued due to their simple process and good performance. From the perspective of rubber materials, it has evolved from a single type of rubber in the past to using different types of rubber in the inner, middle and outer layers to adapt to different working environment conditions, generally composed of 2-3 different rubber compounds. In recent years, the development of automobile hoses in China has begun to take shape. Many companies have introduced advanced foreign technology and equipment, and the quality of their products has been greatly improved. However, compared with foreign countries, there is still a big gap, and low- and mid-range products can meet market requirements. High-end products such as fuel pipes, thin braided hoses, heat-resistant pipes, etc. still rely on imports. The matching rate of domestically produced cars of this kind of products is only 40%, and the matching rate of high-end cars is only 5-10%. In addition to nitrile rubber, nitrile rubber/polyvinyl chloride blends are used as rubber materials, and hydrogenated nitrile rubber, chloroether rubber, chlorosulfonated polyethylene, and EPDM rubber are also used.

2.6 Tape products

The production of transmission belts for cars in my country, especially timing belts, started late. After the reform and opening up, some joint ventures have successively introduced foreign advanced technology and equipment and developed corresponding products in order to cooperate with the introduction of the localization of cars, which basically meets the needs of cars; however, there is still a certain gap in product quality and performance compared with similar foreign products. . The production process of the V-belt for automobiles has replaced the edging belt with the trimming belt. In terms of materials, hydrogenated nitrile rubber is mainly used abroad; chloroprene rubber is still the main domestic rubber. A few use EPDM and chlorosulfonated polyethylene elastomers. Hydrogenated nitrile rubber cannot be used because of the high price. Therefore, the service life of the domestic V-belt is only about 100h. Foreign V-belts can be used for 180,000 km, which can be synchronized with car overhaul. There are about 300 automobile transmission belt manufacturers in my country, with a production capacity of 500 million standard meters of V-belts and 20 million synchronous belts.

2.7 Other products

Automotive wiper strips are one of the more problematic varieties of automotive rubber products in my country. The main problems are high noise, inability to wear and low wiping efficiency. The main material of domestic wiper strips is neoprene. Foreign countries have conducted more in-depth research on materials and structures. For example, use EPDM rubber and silicone rubber to replace neoprene, add solid lubricants to the rubber compound, or spray wear-resistant materials on the surface. The quality of automobile wiper strips has attracted the attention of the Chinese people, and some manufacturers have launched relevant research and achieved good results.

Automobile sealant is mainly used for sealing between car body, door steel plate welds and connecting parts. Adhesives for automobiles mainly include PVC hot melt adhesives, asphalt primers and neoprene adhesives.

3. Thoughts on Improving the Technical Level of my country's Automobile Rubber Products

3.1 First, the government must pay great attention to it, and through policy support, guide enterprises to increase investment in technological research.

Relevant government departments should pay attention to the quality of auto parts as a key factor related to car quality. Earnestly organize domestic technical elites in related industries to selectively target several key technologies for research. We can learn from the experience model of "Guangdong-Hong Kong key material technology research" adopted by Guangdong Province in recent years. Organized by the Provincial Department of Science and Technology, experts from enterprises, research institutes, and colleges and universities will screen, demonstrate, establish, and bid on major materials and technologies encountered in the current economic construction of the province and Hong Kong. The research funding is partly allocated by the provincial government and related functional departments, and the enterprise will be jointly developed by the bid-winning enterprise and colleges and universities according to a certain proportion of the corresponding funds. After several years of experimentation, the results have indeed been achieved.

3.2 Carry out the development and research of urgently needed special raw materials, and change the status quo of "cooking without rice".

3.2.1 Synthetic rubber varieties

High-quality EPDM for composite sealing strips and brake skins, fluororubber varieties for skeleton oil seals for engines with high temperature, high pressure, abrasion resistance and good adhesion above 200℃, fluorosilicone rubber, wear-resistant acrylic rubber, hydrogenated carboxyl group Nitrile rubber, oil-resistant silicone rubber and acrylic rubber with excellent low-temperature properties.

3.2.2 New vulcanizing agents, additives and framework materials

To catch up with advanced international countries, develop a new generation of environmentally friendly crosslinking agents, accelerators and additives, high-strength framework materials such as polyester with excellent adhesion, high-strength glass fiber, and aramid with good stability.

3.3 The enterprise unites scientific research institutes and institutions of higher learning to organize capable scientific research forces to focus on accelerating the development of high-precision products in a short period of time, and increase the rate of localization of high-end vehicles.

1. Car crankshaft high-speed oil seal, crankshaft oil seal, meet 8000Km, temperature 250℃, working life 4000-5000h;

2. Liquid-sealed composite shock absorber, torsion shock absorber, electronic shock absorber, temperature resistance 300℃;

3. Heat-resistant fuel hose and thin-walled hose (wall thickness ≤ 2mm);

4. Multi-channel special-shaped hose;

5. The high-strength rubber film is required to be resistant to high and low temperatures and has a lifespan of 50×10000 times at room temperature.