Rubber products rubber is also called elastomer. The word rubber comes from the Indian cau-uchihu, which means "weeping tree". The main raw material for making rubber is natural rubber, which is made of latex of rubber tree with three leaves solidified and dried. 1770, British chemist J. priestley discovered that rubber can be used to erase pencil handwriting. At that time, this material was called rubber, which is still in use today.
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Source and application
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Professional use
Workpiece machining
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Various material characteristics
China rubber industry
reference data
Rubber-Physical and chemical properties
Rubber: A high elastic polymer material with reversible deformation. It is elastic at room temperature, and can produce large deformation under the action of small external force, and can be restored to its original state after removing external force. Rubber is a completely amorphous polymer with low glass transition temperature (T g) and high molecular weight, exceeding several hundred thousand. Rubber is a kind of highly elastic polymer with chain-like molecular structure and high flexibility. The molecular chain of rubber can be crosslinked (vulcanized), and the crosslinked material has the ability of rapid recovery when deformed by external force, and has good physical and mechanical properties and chemical stability. Only after crosslinking can rubber become a valuable high elastic material, commonly known as rubber. Rubber is the basic raw material of rubber industry, which is widely used to manufacture rubber products such as tires, hoses, tapes and cables. It is as important as metal, chemical fiber and plastic.
Rubber. Classification
Rubber products Rubber is divided into natural rubber and synthetic rubber according to raw materials. According to performance, it can be divided into general type and special type. General-purpose rubber refers to varieties with good comprehensive properties and wide uses, including natural rubber, isoprene rubber, styrene-butadiene rubber and cis-butadiene rubber. Special rubber refers to rubber with some special properties, including chloroprene rubber, nitrile rubber, silicone rubber, fluorine rubber, polyurethane rubber, polysulfide rubber, chlorohydrin rubber, acrylate rubber and so on. According to the form of rubber, there are latex, liquid rubber and powder rubber besides the usual block raw rubber. Latex is a colloidal water dispersion of rubber; Liquid rubber is an oligomer of rubber, which is usually a viscous liquid before vulcanization; Powder rubber is made by processing latex into powder, which is convenient for batching and processing. In addition, the thermoplastic rubber developed in 1960s is a kind of thermoplastic elastomer, which is a synthetic rubber molded into products by the processing method of thermoplastic without chemical vulcanization.
Rubber-Sources and Applications
Rubber products The main raw material for making rubber is natural rubber, mainly from rubber tree with three leaves. When the epidermis of this rubber tree is cut open, milky white juice will flow out, which is called latex. The latex is coagulated, washed, molded and dried to obtain natural rubber. Synthetic rubber is artificially synthesized, and different kinds of rubber can be synthesized by using different raw materials (monomers).
Universal rubber
Universal rubber refers to rubber that partially or completely replaces natural rubber, such as styrene-butadiene rubber, cis-butadiene rubber and isoprene rubber. , mainly used for manufacturing tires and general industrial rubber products. General rubber is in great demand and is the main variety of synthetic rubber.
butadiene-styrene rubber
Styrene-butadiene rubber (SBR), which is polymerized from butadiene and styrene, is the most widely used synthetic rubber, including emulsion styrene-butadiene rubber, solution styrene-butadiene rubber and thermoplastic rubber (SBS).
Sisden
It is made of butadiene by solution polymerization, and cis-polybutadiene rubber has excellent cold resistance, wear resistance and elasticity, as well as good aging resistance. Most of cis-polybutadiene rubber is used to produce tires, and a small part is used to make cold-resistant products, cushioning materials, adhesive tapes, rubber shoes and so on. The disadvantages of cis-polybutadiene rubber are poor tear resistance and poor wet skid resistance.
isoprene rubber
Isoprene rubber is the abbreviation of polyisoprene rubber, which is produced by solution polymerization. Like natural rubber, isoprene rubber has good elasticity and wear resistance, excellent heat resistance and good chemical stability. The strength of raw isoprene rubber (unprocessed) is obviously lower than that of natural rubber, but its quality uniformity and processability are better than that of natural rubber. Isoprene rubber can replace natural rubber to make truck tires and off-road tires, and can also be used to produce various rubber products.
ethylene propylene rubber
Ethylene-propylene rubber is synthesized from ethylene and propylene, which has outstanding aging resistance, electrical insulation and ozone resistance. Ethylene propylene rubber can be filled with a lot of oil and carbon black, and the product price is low. Ethylene propylene rubber has good chemical stability, and its wear resistance, elasticity and oil resistance are close to those of styrene butadiene rubber. Ethylene propylene rubber is widely used, which can be used as tire sidewall, rubber strip, inner tube and automobile parts, and can also be used as wire and cable sheath and high voltage and ultra-high voltage insulation material. You can also make light-colored products, such as rubber shoes and sanitary products.
chloroprene rubber
It is made of chloroprene as the main raw material by homopolymerization or polymerization of a small amount of other monomers. For example, it has high tensile strength, excellent heat resistance, light resistance and aging resistance, and oil resistance is better than natural rubber, styrene-butadiene rubber and cis-butadiene rubber. It has strong flame retardancy and excellent flame retardancy, high chemical stability and good water resistance. The disadvantages of chloroprene rubber are poor electrical insulation and cold resistance, and the raw rubber is unstable during storage. Neoprene rubber has a wide range of uses, such as making covering materials for transportation belts and transmission belts, wires and cables, making oil-resistant hoses, gaskets and chemical-resistant equipment linings.
Rubber structural type
Linear structure of rubber products: common structure of unvulcanized rubber. Because of its large molecular weight, it is fine spherical without external force. When external force is applied and removed, the entanglement degree of fine particles changes, and the molecular chain rebounds, resulting in a strong recovery tendency, which is the origin of rubber's high elasticity.
Branched chain structure: the branches of rubber macromolecular chain gather to form gel. Gel is not good for rubber properties and processing. In the process of rubber mixing, various compounding agents often increase the gel area, forming local blank, unable to form reinforcement and crosslinking, and become the weak part of the product.
Cross-linked structure: linear molecules are connected with each other through some atoms or atomic groups to form a three-dimensional network structure. With the progress of vulcanization, this structure has been continuously strengthened. In this way, the free movement ability of the chain segment decreases, the plasticity and elongation decrease, the strength, elasticity and hardness increase, and the compression set and swelling degree decrease.
Rubber-professional use
Rubber for tires has good comprehensive properties and is widely used. Mainly includes: ① natural rubber. It is made from latex of Hevea brasiliensis, and its basic chemical composition is cis-polyisoprene. Good elasticity, high strength and comprehensive performance. ② Isoprene rubber. The full name is cis-1, 4- polyisoprene rubber, which is a high cis-synthetic rubber made of isoprene. Because its structure and performance are similar to natural rubber, it is also called synthetic natural rubber. ③ Styrene-butadiene rubber. Short for SBR, it is polymerized from butadiene and styrene. According to the production methods, it is divided into emulsion polymerized styrene-butadiene rubber and solution polymerized styrene-butadiene rubber. Its comprehensive performance and chemical stability are good. ④ Butadiene rubber. The full name is cis-1, 4- polybutadiene rubber, abBReviated as br, which is polymerized from butadiene. Compared with other general rubber, vulcanized cis-polybutadiene rubber has excellent cold resistance, wear resistance and elasticity, less heat generation under dynamic load and good aging resistance, and is easy to be used with natural rubber, chloroprene rubber and nitrile rubber.
Special rubber refers to rubber with some special properties. Mainly includes: ① chloroprene rubber. CR for short is polymerized from chloroprene. It has good comprehensive properties, such as oil resistance, flame retardancy, oxidation resistance and ozone resistance. However, it has high density, easy crystallization and hardening at room temperature, poor storage and poor cold resistance. ② Nitrile rubber. NBR for short is polymerized from butadiene and acrylonitrile. Good oil resistance and aging resistance, and can be used in air at 120℃ or oil at 150℃ for a long time. In addition, it also has water resistance, air tightness and excellent bonding performance. ③ Silicone rubber. The main chain consists of silicon atoms and oxygen atoms alternately, and the silicon atoms have organic groups. High and low temperature resistance, ozone resistance and good electrical insulation. (4) fluororubber. Synthetic rubber with fluorine atoms in its molecular structure. It is usually expressed by the number of fluorine atoms of fluorine-containing units in * * * polymers, such as fluororubber 23, which is a * * * polymer of vinylidene fluoride and chlorotrifluoroethylene. Fluorine rubber is resistant to high temperature, oil and chemical corrosion. (5) polysulfide rubber. It is formed by condensation polymerization of dihalides of alkali metals or alkaline earth metals and polysulfides. It has excellent oil resistance and solvent resistance, but its strength is not high, its aging resistance and processability are not good, and its smell is unpleasant. It is mainly used with nitrile rubber. In addition, there are polyurethane rubber, chlorohydrin rubber, acrylate rubber and so on.
Rubber processing process
This process of rubber products includes basic processes such as plastication, mixing, calendering or extrusion, molding and vulcanization, and each process has different requirements for products, and several auxiliary operations are provided respectively. In order to add various necessary additives to rubber, it is necessary to plasticate raw rubber to improve its plasticity. Then, carbon black, various rubber additives and rubber are evenly mixed to prepare a rubber compound; Extrude a rubber material into a blank with a certain shape; Then it is combined with calendered textile materials (or metal materials) to form semi-finished products; Finally, the semi-finished product with plasticity is vulcanized to make the final product with high elasticity.
Rubber. Classification of specifications
Rubber products Natural rubber can be divided into standard rubber (also called granular rubber), smoke film, concentrated rubber, white crepe film, light color film, transparent rubber and air-dried film. The most commonly used are standard rubber and smoke film. Standard rubber is divided into four grades: I (SCR5), II (SCR 10), III (SCR20) and IV (SCR50), and cigarette rubber is divided into five grades: No.65438+No.0 ~ No.5 cigarette film (RSS 1~RSS5).
Standard glue: Standard glue is mainly divided into No.5 glue, 10 glue and No.20 glue. No.5 glue is the first-class glue and the best glue, with an impurity content of 0.05%; 10 glue is secondary glue, and the impurity content is 0.10%; No.20 glue is a third-grade glue with an impurity content of 0.20%. Different kinds of glue have different uses: No.5 glue is generally used to make tire tubes; 10 glue and 20 glue are generally used to make tire casings.
Smoke film: that is, the smoke and heat produced by burning coconut shells are used to smoke and bake the dehydrated natural film. The purpose of smoking is to dry the film and inject anti-oxidation and anti-corrosion cresol. Smoke film belongs to the primary form of natural rubber.
Concentrated glue: can be used as adhesive material.
Crepe film:
Super thin white crepe film
The goods delivered must be extremely white, uniform, dry and strong rubber.
Discoloration, sour taste, dust, debris, gravel or other foreign objects, oil stains or other stains, signs of oxidation or overheating are not allowed for any reason.
First-class thin white crepe film
The goods delivered must be white, dry and strong rubber. Slight chromatic aberration is allowed.
Discoloration, sour taste, dust, debris, gravel or other foreign objects, oil stains or other stains, signs of oxidation or overheating are not allowed for any reason.
Super lightweight crepe film
The goods delivered must be light, uniform, dry and strong rubber.
Discoloration, sour taste, dust, debris, gravel or other foreign objects, oil stains or other stains, signs of oxidation or overheating are not allowed for any reason.
First-class thin crepe film
The goods delivered must be light-colored, dry and strong rubber. Slight chromatic aberration is allowed.
Discoloration, sour taste, dust, debris, gravel or other foreign objects, oil stains or other stains, signs of oxidation or overheating are not allowed for any reason.
Secondary thin crepe film
The goods delivered must be dry solid rubber. The color is slightly darker than the first-class thin crepe film. Slight chromatic aberration is allowed. Rubber with spots and stripes is allowed to have the degree shown in the sample. However, the number of plastic bags inspected shall not exceed 10% of the number of plastic bags inspected. Except as permitted above, there are no signs of discoloration, dust, debris, gravel or other foreign objects, oil stains or other stains, oxidation or overheating caused by any reason.
Three-grade thin crepe film
The goods delivered must be yellow, dry and strong rubber. Allow different shades of color.
Rubber with spots and stripes is allowed to have the degree shown in the sample. However, the number of plastic bags inspected shall not exceed 20% of the number of plastic bags inspected.
Rubber-characteristics of various materials
Natural rubber NR of rubber factory
Natural rubber is a polymer of isoprene, which is made of latex collected from rubber trees. It has good wear resistance, high elasticity, breaking strength and elongation. It is easy to age in air, become sticky when heated, swell and dissolve in mineral oil or gasoline, and is alkali-resistant but not strong acid-resistant. Advantages: good elasticity, acid and alkali resistance. Disadvantages: weatherproof and oil-resistant (vegetable oil-resistant) are raw materials for making adhesive tapes, rubber hoses and rubber shoes, and are suitable for making shock-absorbing parts and products used in hydroxyl-containing liquids such as automobile brake oil and ethanol.
butadiene-styrene rubber
Compared with natural rubber, the polymer of butadiene and styrene has uniform quality, less impurities, better wear resistance and aging resistance, but weaker mechanical strength, and can be blended with natural rubber. Advantages: low-cost non-oil resistant material, good water resistance, good elasticity below hardness 70, and poor compressibility at high hardness. Disadvantages: Strong acid, ozone, oil, grease and most hydrocarbons are not recommended. Widely used in tire industry, shoe industry, cloth industry and conveyor belt industry.
Butyl rubber IIR
Butyl rubber is polymerized from isobutylene and a small amount of isoprene. Because the movement of sterically hindered molecules of methyl group is less than that of other polymers, it has less air permeability, stronger heat resistance, sunlight resistance and ozone resistance, and better electrical insulation. Resistant to polar solvents, the general temperature range is -54- 1 10℃. Advantages: impermeable to most general gases, good resistance to sunlight and odor, and contact with animals or vegetable oils or evaporable chemicals. Disadvantages: It is not recommended to use the inner tube, leather bag, rubber paste paper, window frame adhesive, steam hose and heat-resistant conveyor belt of automobile tires with petroleum solvent, rubber kerosene and aromatic hydrogen at the same time.
Hydrogenated Ding Qing rubber HNBR
Hydrogenated Ding Qing rubber is a kind of Ding Qing rubber, in which some double chains are removed after hydrogenation. After hydrogenation, the temperature resistance and weather resistance are much higher than those of ordinary Ding Qing rubber, and the oil resistance is similar to that of ordinary Ding Qing rubber. The general temperature range is -25 to 150℃. Advantages: Compared with Ding Qing rubber, it has better wear resistance, excellent corrosion resistance, tensile strength, tear resistance and compressibility. It has good resistance under atmospheric conditions such as ozone, and is generally suitable for washing clothes or washing dishes. Disadvantages: It is not recommended to be used in air conditioning and refrigeration industry in alcohol, ester or aromatic solution, but widely used as a seal in environmental protection refrigerant R 134a system.
Automobile engine system seal.
ethylene propylene rubber
Ethylene propylene rubber is polymerized from ethylene and propylene, so it has excellent heat resistance, aging resistance, ozone resistance and stability, but sulfur cannot be added. In order to solve this problem, a small amount of double-stranded third component is introduced into the main chain of EP, and EPDM can be obtained by adding sulfur. Generally, the temperature is -50 to 150℃. Excellent resistance to polar solvents, such as alcohol and ketone. Advantages: good weather resistance and ozone resistance, excellent water resistance and chemical resistance, alcohol and ketone can be used, high temperature steam resistance and good air tightness. Disadvantages: Not recommended for food or contact with aromatic hydrogen. Seals, sanitary ware seals or parts in high temperature steam environment. Rubber parts in braking system. Seals in radiator (automobile water tank).
Butadiene nitrile rubber
(NBR) is polymerized from acrylonitrile and butadiene. The content of acrylonitrile ranges from18% to 50%. The higher the acrylonitrile content, the better the hydrocarbon-resistant fuel oil performance of petrochemical products, but the low-temperature performance is poor. The general temperature range is -25 to 100℃. Ding Qing rubber is one of the most commonly used rubbers for oil seals and O-rings at present: it has good oil resistance, water resistance, solvent resistance and high-pressure oil resistance, and has good compressibility, wear resistance and elongation. Disadvantages: Not suitable for polar solvents, such as ketones, ozone and nitrohydrocarbons. It is used to manufacture oil tanks, lubricating oil tanks and rubber parts, especially seals, used in fluid media such as petroleum hydraulic oil, gasoline, water, silicone oil and diester lubricating oil. It can be said that it is the most widely used rubber seal with the lowest cost at present.
Neoprene CR
Neoprene rubber is polymerized from chloroprene monomer. Vulcanized rubber has good elasticity and wear resistance, not afraid of direct sunlight, especially good weather resistance and strong distortion, refrigerant, dilute acid and silicone ester lubricating oil, but not phosphate ester hydraulic oil. It is easy to crystallize and harden at low temperature and has poor storage stability. It has great expansion in mineral oil with low aniline point. The general temperature range is -50 to 150℃. Advantages: good elasticity, good compression deformability, sulfur-free formula and easy manufacture. It has the characteristics of animal and vegetable oil resistance, will not be affected by neutral chemicals, fats, oils, various oils and solvents, and has the characteristics of flame retardant. Disadvantages: It is not recommended to use R 12 refrigerant-resistant seals in chemicals such as strong acids, nitro-hydrocarbons, esters, chloroform and ketones, and rubber parts or seals on household appliances. Suitable for making all kinds of parts that are in direct contact with the atmosphere, sunlight and ozone. Suitable for all kinds of rubber products with fire resistance and chemical corrosion resistance.
Rubber-china rubber Industry
Rubber factory rubber industry is one of the important basic industries of national economy. Not only provide people with daily necessities, medical and other light industrial rubber products, but also provide various rubber production equipment or rubber parts to heavy industries and emerging industries such as mining, transportation, construction, machinery and electronics. It can be seen that there are many kinds of products in the rubber industry, and the backward industries are very broad.
In recent years, the rubber industry has made great progress. The existing sub-industries have risen steadily, and the new rubber sub-industries have developed rapidly. At the same time, there are still some problems in rubber industry, such as environment, resources, disasters and innovation.
In 2004, the total planting area of natural rubber in China was 696,200 hectares, the cutting area was 45 1.9 million hectares, and the dry rubber output was 573,300 tons. Among them, the planting area of rubber in state farms is 4 1. 1.00 million hectares, and that in private enterprises is 285,200 hectares, accounting for 59.03% and 40.97% of the total rubber area in China respectively.
In 2005, Hainan suffered a severe drought once in 50 years and a typhoon once in 100 years, and the production of natural rubber was hit hard. In order to tap the development potential of domestic natural rubber planting and processing, and improve self-sufficiency, china rubber industry has made unremitting efforts, conscientiously implemented the policy of national security, energy saving, environmental protection and clean production, and achieved great results. In particular, the rubber additives industry actively adjusted the product structure, and the green additives increased significantly. The yield ratio of excellent antioxidant varieties reached 80%, and the accelerator reached 50%, and the production of toxic, harmful and highly carcinogenic NOBS was effectively controlled. The comprehensive utilization rate of waste rubber reaches more than 65%, which expands the field of post-processing and utilization of reclaimed rubber and rubber powder.
In 2006, the Third Council of the Sixth China Rubber Industry Association discussed, adopted and issued the Opinions on the 11th Five-Year Plan for the Development of Industrial Science in china rubber and the Opinions on the Implementation of Famous Brand Strategic Plan in the 11th Five-Year Plan for the Rubber Industry. This is the first industry plan formulated by the association. The plan shows that the rubber industry should take the road of independent innovation during the Eleventh Five-Year Plan period, and the whole industry should turn to the track of scientific development, so that China will become a powerful rubber industry in the world.
China rubber has a bright industrial prospect. By 20 10, the total consumption of natural rubber in China will reach 2.3 million tons, the product structure of rubber industry will change greatly, the number of new products and updated products will increase, the application of new materials and new processes will expand, and the production technology will make great progress.
The characteristics of rubber industry determine that when a country's rubber industry is mature, its prosperity will maintain a strong correlation with the operation of the whole economy: the length of its development cycle is equivalent to that of the country's economic cycle, with the same trend; However, because the rubber industry belongs to the basic industry, its cycle change is slightly ahead of the economic cycle change. In addition, because the rubber industry is at the front end of the national economic production chain, its periodic fluctuation range is smaller than that of the industry at the end of the industrial chain, and also smaller than that of the whole economy. Therefore, from the perspective of industrial investment, the mature rubber industry is closer to the income-oriented investment industry. Rubber industry is one of the important basic industries of national economy. Not only provide people with daily necessities, medical and other light industrial rubber products, but also provide various rubber production equipment or rubber parts to heavy industries and emerging industries such as mining, transportation, construction, machinery and electronics. It can be seen that there are many kinds of products in the rubber industry, and the backward industries are very broad.