Types, characteristics and uses of rubber products
Rubber products refer to the activities of producing various rubber products using natural and synthetic rubber as raw materials, and also include rubber products regenerated from waste rubber.
(1) General rubber
⒈ Natural rubber NR: It is produced from the latex of the Hevea hevea tree. Its basic chemical component is cis-polyisoprene, which is a polymer of isoprene. It is a raw material for making tapes, hoses, and rubber shoes. It is suitable for making shock-absorbing parts and products used in liquids containing hydroxyl radicals such as automobile brake fluid and ethanol. Advantages: It has good wear resistance, high elasticity, tear strength and elongation, acid and alkali resistance, and good overall performance. Disadvantages: Not resistant to heat and oil (can be resistant to vegetable oil), easy to expand and dissolve in mineral oil or gasoline, resistant to alkali but not strong acid. It ages easily in the air and becomes sticky when exposed to heat.
⒉ Isoprene rubber IR: The full name is cis-1,4-polyisoprene rubber. It is a high-cis synthetic rubber made from isoprene and produced by solution polymerization. Because its structure and properties are similar to natural rubber, it is also called synthetic natural rubber. It can replace natural rubber in the manufacture of truck tires and off-road tires, and can also be used to produce various rubber products. Advantages: Like natural rubber, it has good elasticity and wear resistance, excellent heat resistance and good chemical stability, and its quality uniformity and processing performance are superior to natural rubber. Disadvantages: The strength of raw rubber (before processing) is significantly lower than that of natural rubber.
⒊ Styrene-butadiene rubber SBR: produced by the copolymerization of butadiene and styrene. It is the largest general-purpose synthetic rubber. According to the production method, it is divided into emulsion polymerized styrene-butadiene rubber, solution polymerized styrene-butadiene rubber and thermoplastic rubber (SBR). Widely used in tire industry, shoe industry, cloth industry and conveyor belt industry. Advantages: Low-cost, non-oil-resistant material, good water resistance, good elasticity with hardness below 70, poor compressibility at high hardness. Compared with natural rubber, it has uniform quality, less foreign matter, better wear resistance and aging resistance, and has good comprehensive performance and chemical stability, and can be blended with natural rubber. Disadvantages: Mechanical strength is weak. It is not recommended to use strong acids, ozone, oils, greases, fats and most hydrocarbons.
⒋ Butadiene rubber BR: The full name is cis-1,4-polybutadiene rubber, which is produced by solution polymerization of butadiene. Most of it is used to produce tires, and a small part is used to make cold-resistant products, cushioning materials, tapes, rubber shoes, etc. Advantages: Vulcanized butadiene rubber has particularly excellent cold resistance, wear resistance and elasticity, generates less heat under dynamic load, has good aging resistance, and can be easily used together with natural rubber, chloroprene rubber, nitrile rubber, etc. Disadvantages: Poor tear resistance and poor wet and slip resistance.
⒌ Chloroprene CR: Made of chloroprene as the main raw material, it is formed by homopolymerization or copolymerization of a small amount of other monomers. The vulcanized rubber has good elasticity and wear resistance. The formula does not contain sulfur, so it is very easy to make. It has particularly good weather resistance, is not afraid of violent distortion, is not afraid of refrigerants, is resistant to dilute acids and silicone lubricants, and is generally used. The temperature range is -50-150 ℃. Neoprene has a wide range of uses, such as making transport belts and transmission belts, covering materials for wires and cables, making oil-resistant hoses, gaskets, and chemical-resistant equipment linings. Make various parts that are in direct contact with the atmosphere, sunlight, and ozone. Suitable for all kinds of flame-resistant and chemical-resistant rubber products. It is not recommended to use strong acids, nitro hydrocarbons, esters, chloroform and ketone chemicals, seals resistant to R12 refrigerant, and rubber parts or seals on household appliances.
Advantages: It has good comprehensive properties, such as high tensile strength, water resistance, oil resistance, flame resistance, heat resistance, light resistance, aging resistance, oxidation resistance and ozone resistance. It has good elasticity and compression deformation, is resistant to animal and vegetable oils, will not be affected by neutral chemical fats, greases, various oils, and solvents, and has flame-proof properties. High chemical stability. Disadvantages: High density, easy to crystallize and harden at room temperature, poor storage properties, poor electrical insulation performance, cold resistance, easy to crystallize and harden at low temperatures, raw rubber is unstable during storage. Not resistant to phosphate ester hydraulic oil. The expansion is large in mineral oil with low aniline point.
⒍ Ethylene-propylene rubber EPDM: Synthesized with ethylene and propylene as the main raw materials, it has good chemical stability, and its wear resistance, elasticity, and oil resistance are close to those of styrene-butadiene rubber. A small amount of a double-stranded third component is introduced into the EP main chain and sulfur can be added to form EPDM. The general use temperature is minus 50-150 ℃. Excellent resistance to polar solvents such as alcohols and ketones. It has a wide range of uses and can be used as tire sidewalls, rubber strips, inner tubes, and automobile parts. It can also be used as wire and cable sheaths and high-voltage and ultra-high-voltage insulation materials. Manufacture of rubber shoes, sanitary products and other light-colored products. It can be filled with a large amount of oil and carbon black, and the product price is low. It is often used as seals or parts in high-temperature water vapor environments and bathroom equipment. Rubber parts in braking (braking) systems. Seals in radiators (car radiators). Advantages: Good weather resistance and ozone resistance, excellent water resistance and chemical resistance, can use alcohols and ketones, resistant to high temperature steam, and has good impermeability to gases. It has excellent heat resistance, aging resistance, ozone resistance, and electrical insulation stability. Disadvantages: Not recommended for food use or exposure to aromatic hydrocarbons.
⒎ Butyl rubber IIR: It is polymerized from isobutylene and a small amount of isoprene. Because the steric hindrance of the methyl group is less than that of other polymers, the general use temperature range is minus 54-110 ℃. Commonly used in automobile tire inner tubes, leather bags, rubber plaster paper, window frame rubber, steam hoses, heat-resistant conveyor belts, etc. Advantages: Impermeable to most gases, highly resistant to heat, sunlight, and ozone, and good electrical insulation; highly resistant to polar solvents, and can be exposed to animal or vegetable oils or vaporizable chemicals. Disadvantages: It is not recommended to use it with petroleum solvents, glue kerosene and aromatic hydrocarbons at the same time.