Three main rubber accessories:

1. Sealing ring

In recent years, China's automotive rubber pipe fittings industry has introduced foreign technology, equipment, and technological transformation, giving rise to a group of backbone enterprises with a large consumption range and high degree, gradually forming a relatively complete industrial system that can fundamentally meet and meet the needs of China's automotive industry. At present, there are about 30 sealing ring factories in China with a certain scope and degree, with a total consumption of about 200 million pieces. Domestically available for consumption include various types of sealing rings that are resistant to oil, high temperature, and aging, which can meet the needs of the domestic automotive market. However, due to the high-speed development of automobiles and the involvement of fuel additives, the temperature, medium resistance, and accuracy of sealing rings are increasingly improving. Therefore, we need to develop new materials and optimize product construction to meet the requirements of detailed automotive application environments.

2. Shock absorber pad

China has more than 20 rubber shock absorber product factories with a considerable range, with a consumption capacity of about 70 million pieces, which can basically meet the needs of domestic automobile consumption matching and maintenance exchange. At present, foreign countries have successfully developed sealed shock absorbers. China's automotive shock absorber products still mainly use natural rubber, fluororubber, EPDM rubber, and nitrile rubber. As an indispensable component of automotive rubber parts, it plays an important role.

3rubber tube

for automotive userubber tubeIn recent years, it has grown at a rate of about 25%, and there are more than 20 automobile hose factories in China, with a total consumption of 200 million standard meters. The proportion of resin composite rubber hoses, including brake hoses and cooling water pipes, is increasing, mainly consisting of woven rubber hoses and wrapped rubber hoses; Short fiber rubber hoses have attracted attention due to their simple process and good performance. From the data of rubber tubes, it can be seen that the development has shifted from using a single type of rubber to using different types of rubber for the inner, middle, and outer layers to adapt to different working environment conditions. Generally, 2-3 different types of rubber are compounded together. In recent years, the development of automotive rubber hoses in China has begun to take shape, and many enterprises have introduced foreign technology and equipment, resulting in significant progress in production quality and quantity. However, there is still a significant gap compared to foreign countries, and mid to low end products can meet market demands. High quality products such as fuel pipes, thin braided rubber hoses, heat-resistant pipes, etc. still rely on foreign products. In addition to using nitrile rubber, rubber tube materials also use nitrile rubber/polyvinyl chloride blend rubber, and further use hydrogenated nitrile rubber, chloroether rubber, chlorosulfonated polyethylene, and ethylene propylene diene monomer rubber.
In fact, the aging of rubber pipe fittings is also a normal phenomenon. As they will age after long-term use, some people believe that the ozone oxidation process of rubber pipes is a combination of physical and chemical processes. When the rubber tube comes into contact with ozone, the double bonds on the surface quickly react with ozone, generating ozone in most parts, causing the originally smooth rubber tube chain to quickly transform into a rigid chain containing many ozone rings. When stress is applied to the rubber tube, the stress stretches and unfolds the rubber tube chain, causing more double bonds to come into contact with ozone, resulting in the rubber chain containing more ozone rings and becoming more brittle. The brittle surface is prone to cracking under stress or dynamic stress.

Rubber fittings may experience aging due to various reasons, and what are the important reasons for this?

That is ozone, which is more reactive than oxygen, so its invasion of rubber pipes, especially unsaturated rubber pipes, is much more severe than oxygen. Ozone (O3) in the atmosphere is synthesized by oxygen molecules absorbing short wave ultraviolet light from the sun, and the oxygen atoms are separated from the oxygen molecules again. At a distance of 20 from the surface of the Earth? There is an ozone layer with a concentration of about 5X10- in the sky at a height of 30km. As the air moves vertically, ozone is carried to the surface of the Earth, and its concentration gradually decreases from high altitude to the sky.

As is well known, cars cannot do without rubber hoses. Each car has over 100 types of rubber pipe fittings, ranging from 200 to 500 pieces, with a rubber consumption of up to 60 kilograms. Rubber parts for automobiles account for over 6% of the total cost of automobiles. Rubber parts used in automobiles, such as the engine, gearbox, and axles, require oil seals. However, small rubber oil seals are the key to ensuring the normal operation of these components, safeguarding the safety and durability of automobiles. Therefore, rubber parts can be regarded as the "functional cells" of automobiles.

Detailed explanation of the main properties and characteristics of rubber parts:

1. Mechanical properties under normal conditions

The tensile strength of 26 type fluororubber after compounding is 10-20MPa; Elongation rate of 150%~300%; The tear strength is between 20-40kN/m, but its elasticity is poor. The friction coefficient of fluororubber is smaller than that of nitrile rubber.

2. High temperature resistance performance

At present, fluororubber has excellent high temperature resistance. Fluororubber can work for a long time at 200-250 degrees Celsius and for a short time at 300 degrees Celsius. Rapid decrease with increasing temperature; Between 150-260 degrees Celsius, as the temperature increases, the descent tends to slow down.

3. Corrosion resistance performance

Fluororubber has superior corrosion resistance. It has excellent stability to organic liquids, different fuel oils, and smooth oils, and has good corrosion resistance to most local inorganic acids, hydrocarbons, benzene, and toluene. It is only not resistant to low molecular weight esters, ethers, ketones, and local amine compounds.

4. Performance of resistance to hot water and superheated steam

The stability of rubber pipes in the action of hot water depends not only on the material of the body, but also on the matching technology of the rubber material.

5. Tightening permanent deformation performance

Fluororubber is used for sealing at high temperatures, and its key is its compression deformation performance. The widespread application of fluororubber is inseparable from its improved compression deformation.

After using rubber accessories for a period of time, they may exhibit vulcanization phenomenon. What is the detailed process of presentation?

1. Guidance stage: Firstly, there is the interaction between sulfur, accelerator, and activator, which increases the solubility of zinc oxide in the rubber material. Activation accelerator is formed by the reaction between accelerator and sulfur, resulting in a more active intermediate product.

2. Corresponding vulcanization curve → coke burning stage: operation coke burning time, remaining coke burning time. Its length is related to the safety of consumption and processing, determined by the composition of the rubber formula, mainly influenced by the promoter.

3. Operation burn time: The burn time consumed during the processing of automotive rubber pipe fittings due to thermal accumulation effects.

4. Remaining burning time: The time during which the adhesive material remains active while heating in the model.

5. Crosslinking stage: Crosslinking free radicals (or ions) react with rubber tube molecular chains to generate crosslinking bonds corresponding to the vulcanization curve → Thermal vulcanization stage: The length of time depends on temperature and the formula of automotive rubber tube accessories. The higher the temperature, the more accelerator is used, and the faster the vulcanization rate. The slope of the curve represents the vulcanization reaction rate, and the larger the slope, the faster the vulcanization reaction rate and the higher the consumption efficiency.

6. Network composition stage: In the early stage of this stage, cross-linking reactions have already formed, and the initial cross-linking bonds undergo shortening, rearrangement, and cleavage reactions. In addition, the network tends to stabilize, and a relatively stable vulcanized rubber is obtained. Corresponding vulcanization curve → flat vulcanization stage: In the early stage of network composition, the cross-linking reaction has been fundamentally completed, followed by reactions such as rearrangement and cracking of cross-linking bonds. The strength curve of the rubber material shows a flat period, and the flat vulcanization time depends on the rubber formula.

What are the characteristics of silicone rubber parts?

1. With good processing performance and easy molding, various products can be manufactured through methods such as extrusion hot air vulcanization molding, mold addition molding, and extension molding.

2. Temperature resistance: It can be used for a long time at 200 ℃ and still has elasticity at -60 ℃.

3. Electrical insulation performance: The dielectric performance of silicone rubber pipes is excellent, especially at high temperatures, which greatly exceeds that of ordinary organic rubber pipes. The dielectric strength is almost unaffected by temperature in the range of 20-200 ℃.

4. Excellent high-temperature compression for permanent deformation.

5. Excellent weather resistance, ozone resistance, and UV resistance, and long-term outdoor use without cracking. It is generally believed that silicone rubber pipes can be used outdoors for more than 20 years.