Rubber tube products时间：2021-09-26浏览次数：600
Three main rubber accessories:
1. Sealing ring
In recent years, after the introduction of foreign technology, equipment and technological transformation, China's automobile rubber pipe fittings industry has emerged a number of backbone enterprises with a large consumption range and a high degree, gradually forming a relatively complete industrial system, which can fundamentally meet and comply with the needs of China's automobile industry. At present, there are more than 30 seal ring factories with a certain range and degree in China, with a total consumption of about 200million pieces. Domestic consumption includes oil resistant, high temperature resistant, aging resistant and other types of sealing rings, which can meet the needs of the domestic automotive market. However, due to the high speed of the automobile and the participation of fuel additives, the application temperature, medium resistance and accuracy of the sealing ring are improving day by day. Therefore, we need to develop new materials and optimize the product structure to meet the requirements of the detailed application environment of automobiles.
2. Damping pad
China has more than 20 rubber shock absorption products factories with a considerable range, whose consumption capacity is about 70million pieces, which can basically meet the needs of domestic automobile consumption and maintenance exchange. At present, foreign countries have successfully developed liquid sealed shock absorbers. Natural rubber, fluororubber, ethylene propylene diene monomer and nitrile rubber are still the main automotive shock absorbers in China. As an indispensable part of automobile rubber parts, it plays an important role.
For automobileRubber tubeWith a growth rate of about 25% in recent years, there are more than 20 automobile hose factories in a certain range in China, and the total consumption can reach 200million standard meters. Braided rubber hose and winding rubber hose are the main ones, and the proportion of resin composite rubber hose, including brake rubber hose and cooling water pipe, is increasing; Short fiber rubber hose is paid attention to because of its simple process and good performance. From the data of rubber pipes, it has been carried out from a single kind of rubber in the past to adopt different kinds of rubber in the inner, middle and outer layers to adapt to different working environmental conditions. It is generally composed of 2-3 kinds of different rubber. In recent years, the development of automotive rubber hoses in China has begun to take shape. Many enterprises have introduced foreign technology and equipment, and the production and quality have made great progress. However, compared with foreign countries, there is still a large gap. Medium and low-grade products can meet the market requirements. High quality products such as fuel pipes, thin braided rubber hoses, heat-resistant pipes and so on still rely on foreign products. In addition to nitrile rubber, nitrile rubber / PVC blend rubber is also used for rubber pipe materials, and hydrogenated nitrile rubber, Chloroether rubber, chlorosulfonated polyethylene and ethylene propylene diene monomer are further applied.
In fact, aging of rubber pipe fittings is also a normal phenomenon. It will age after long-term use. Some people also think that the ozonation process of rubber pipes is a process of physical and chemical processes. When the rubber tube is in contact with ozone, the double bond on the surface quickly reacts with ozone, and most of it generates ozone, which quickly turns the originally flexible rubber tube chain into a rigid chain containing many ozone rings. When stress is applied to the rubber tube, the stress will stretch the rubber tube chain, so that more double bonds are in contact with ozone, so that the rubber chain contains more ozone rings and becomes more brittle. The brittle surface is easy to crack under the action of stress or dynamic stress.
Rubber pipe fittings will lead to aging problems for some reasons, and what is the important reason?
That is ozone. Ozone is more vivid than oxygen, so its attack on rubber tubes, especially unsaturated rubber tubes, is much more serious than oxygen. Ozone (O3) in the atmosphere is formed by the re separation of oxygen atoms and oxygen molecules after oxygen molecules absorb the short wavelength ultraviolet light in the sunlight. At a distance of 20? At a height of 30km, there is an ozone layer with a concentration of about 5x10 - 'with the vertical activity of the air, ozone is brought to the earth's surface, and the concentration of ozone gradually decreases from high altitude to the air.
As we all know, cars can't live without rubber pipes. There are more than 100 kinds of rubber pipe fittings for each vehicle, ranging from 200 to 500, and the rubber consumption can reach 60 kg. Rubber products and accessories for automobiles account for more than 6% of the total cost of automobiles. Oil seals are used in automobile rubber accessories, such as the starter, gearbox, axle and other parts of the automobile, but small rubber oil seals are the key to ensure the normal operation of these parts and protect the safe and durable use of the automobile. Therefore, rubber accessories can be described as the "functional cell" of the automobile.
Detailed explanation of main properties and characteristics of rubber parts:
1. Mechanical properties under normal conditions
The tensile strength of 26 type fluororubber after mixing is 10~20mpa; Elongation 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
At present, fluororubber has excellent high temperature resistance. Fluororubber can work for a long time at 200~250 ℃ and for a short time at 300 ℃. It decreases rapidly with the increase of temperature; Between 150-260 degrees Celsius, the decline tends to slow with the increase of temperature.
3. Corrosion resistance
Fluororubber has excellent corrosion resistance. It has excellent stability to organic liquids, different fuel oils and smooth oils, good corrosion resistance to most local inorganic acids, hydrocarbons, benzene and toluene, and is only not resistant to low molecular esters, ethers, ketones and local amines.
4. Resistance to hot water and superheated steam
The stability of rubber pipes to hot water depends not only on the body data, but also on the compounding technology of rubber.
5. Compact permanent deformation performance
Fluororubber is used for sealing at high temperature, and its shrinkage deformation performance is the key. Fluororubber has been widely used because of its tightening and deformation improvement.
Rubber accessories may appear vulcanization after being used for a period of time. What is the detailed presentation process?
1. Guiding stage: first, the interaction of sulfur, accelerator and activator is the increase of the solubility of zinc oxide in the compound, and the activation of accelerator is the reaction between accelerator and sulfur to produce an intermediate product with greater activity.
2. Corresponding vulcanization curve → scorch stage: Operation scorch time and remaining scorch time. Its length is related to the safety of consumption and processing, which depends on the composition of the compound formula and is mainly affected by the accelerator.
3. Operation scorch time: the scorch time consumed in the processing of automobile rubber pipe fittings due to heat accumulation effect.
4. Remaining scorch time: the time for the rubber to adhere to the activity when heated in the model.
5. Crosslinking stage: the crosslinkable free radical (or ion) reacts with the molecular chain of the rubber tube and generates a crosslinking bond corresponding to the vulcanization curve → thermal vulcanization stage: the length of time depends on the temperature and the formula of automobile rubber tube accessories. The higher the temperature is, the more the accelerator is used, and the faster the vulcanization speed is. The slope of the curve represents the vulcanization reaction rate. The larger the slope, the faster the vulcanization reaction rate and the higher the consumption efficiency.
6. Network formation stage: in the early stage of this stage, the crosslinking reaction has tended to form, and the crosslinking bond in the initial stage has shortened, rearranged and cracked reactions. In addition, the network tends to be stable, and the vulcanizate with relatively stable network is obtained. Corresponding vulcanization curve → leveling vulcanization stage: in the early stage of network composition, the cross-linking reaction has been basically completed, and then the rearrangement and cracking of cross-linking bonds occur. The strength curve of the compound presents a leveling period, and the leveling vulcanization time depends on the formula of the compound.
What are the characteristics of silicone rubber parts?
1. It has the advantages of good processing performance and easy molding, and can produce various products through extrusion hot air vulcanization molding, mold addition molding, extension molding and other methods.
2. Upper and lower temperature resistance: it can be used for a long time at 200 ℃, and it is still elastic at -60 ℃.
3. Electrical insulation performance: the dielectric performance of silicone rubber tube is excellent, especially at high temperature, the dielectric performance is much higher than that of ordinary organic rubber tube, and the dielectric strength is hardly affected by temperature in the range of 20-200 ℃.
4. Excellent high temperature compression and eternal deformation.
5. Excellent weather resistance, ozone resistance and UV mapping performance, no cracking when used outdoors for a long time. It is generally believed that silicone rubber pipes can be used outdoors for more than 20 years.