Basic knowledge of rubber varieties

1. Natural rubber (NR) is mainly rubber hydrocarbon (polyisoprene), containing a small amount of protein, water, resin acid, sugar and inorganic salt. High elasticity, high tensile strength, good tear resistance and electrical insulation, good abrasion resistance and drought resistance, good processability, easy to bond with other materials, and superior to most synthetic rubbers in comprehensive performance. The disadvantages are poor oxygen resistance and ozone resistance, easy to aging and deterioration; Poor oil and solvent resistance, low acid and alkali resistance; The heat resistance is not high. Operating temperature range: about – 60 ℃~+80 ℃. To make tyres, rubber shoes, rubber hoses, adhesive tapes, insulating layers and sheaths of wires and cables and other general products. It is especially suitable for manufacturing torsional vibration eliminator, engine shock absorber, machine support, rubber metal suspension components, diaphragms and molded products.

2. Copolymer of styrene butadiene rubber (SBR) and butadiene. Its performance is close to that of natural rubber, and it is the largest general synthetic rubber with the characteristics of wear resistance, aging resistance and heat resistance. Its texture is more uniform than that of natural rubber. Disadvantages: low elasticity, poor bending and tear resistance; Poor processability, especially poor self adhesion and low raw rubber strength. Operating temperature range: about – 50 ℃~+100 ℃. It is mainly used to replace natural rubber to make tyres, rubber plates, rubber hoses, rubber shoes and other general products.

3. cis polybutadiene rubber (BR) is a cis structural rubber polymerized from butadiene. Advantages: excellent elasticity and wear resistance, good aging resistance, excellent low temperature resistance, low heat under dynamic load, easy metal bonding. The disadvantages are low strength, poor tear resistance, poor processing performance and self adhesion. Operating temperature range: about – 60 ℃~+100 ℃. It is usually used together with natural rubber or styrene butadiene rubber, mainly for making tire tread, transport belt and special cold resistant products.

4. Isoprene rubber (IR) is a cis structural rubber polymerized from isoprene monomer. The chemical composition and three-dimensional structure are similar to natural rubber, and the performance is also very close to natural rubber, so it is called synthetic natural rubber. It has most of the advantages of natural rubber. Due to its aging resistance, the elasticity and strength of natural rubber are slightly lower than that of natural rubber, with poor processing performance and high cost. Use temperature range: about – 50 ℃~+100 ℃ can replace natural rubber to make tires, rubber shoes, rubber hoses, tapes and other general products.

5. Neoprene rubber (CR) is a polymer polymerized by chloroprene as monomer lotion. This rubber molecule contains chlorine atoms, so compared with other general rubber, it has excellent oxygen resistance, ozone resistance, non flammable, self extinguishing after fire, oil resistance, solvent resistance, acid and alkali resistance, aging resistance, good air tightness, etc; Its physical and mechanical properties are also better than natural rubber, so it can be used as general rubber and special rubber. The main disadvantages are poor cold resistance, large proportion, high relative cost, poor electrical insulation, easy to stick and roll, easy to scorch and easy to stick to the mold during processing. In addition, the raw rubber has poor stability and is not easy to preserve. Operating temperature range: about – 45 ℃~+100 ℃. It is mainly used to manufacture cable sheaths and various protective sleeves and covers with high ozone resistance and aging resistance; Oil and chemical resistant rubber hose, tape and chemical lining; Fire resistant rubber products for underground mining, as well as various molded products, sealing rings, gaskets, adhesives, etc.

6. IIR is a copolymer of isobutene and a small amount of isoprene or butadiene. The biggest characteristics are good air tightness, ozone resistance, aging resistance, high heat resistance, long-term working temperature can be below 130 ℃; It is resistant to strong inorganic acids (such as sulfuric acid, nitric acid, etc.) and general organic solvents, with good vibration absorption and damping characteristics and excellent electrical insulation. The disadvantages are poor elasticity, poor processability, slow curing speed, poor adhesion and oil resistance. Operating temperature range: about – 40 ℃~+120 ℃. It is mainly used for inner tube, water tube, balloon, wire and cable insulation layer, chemical equipment lining and shockproof products, heat-resistant transport belt, and heat-resistant aging adhesive tape products.

7. Copolymer of butadiene acrylonitrile butadiene rubber (NBR) and acrylonitrile. It is characterized by excellent resistance to gasoline and fatty hydrocarbon oil, second only to polysulfide rubber, acrylate and fluororubber, and superior to other general rubber. Good heat resistance, air tightness, wear resistance and water resistance, strong adhesion. The disadvantages are poor cold resistance and ozone resistance, low strength and elasticity, poor acid resistance, poor electrical insulation, and poor resistance to polar solvents. Operating temperature range: about – 30 ℃~+100 ℃. It is mainly used to manufacture various oil resistant products, such as rubber hose, sealing products, etc.

8. Copolymer of hydrogenated nitrile butadiene rubber (HNBR) butadiene and acrylonitrile. It is obtained by fully or partially hydrogenating the double bond in butadiene of NBR. It is characterized by high mechanical strength and wear resistance. When cross-linked with peroxide, its heat resistance is better than NBR. Other properties are the same as NBR. The disadvantage is that the price is high. Operating temperature range: about － 30 ℃～ ＋ 150 ℃. It is mainly used for oil and high temperature resistant sealing products.

9. The copolymerization of ethylene and propylene of ethylene propylene rubber (EPDM  EPDM) is generally divided into ethylene propylene diene monomer (EPDM) and ethylene propylene diene monomer (EPDM). It is characterized by excellent ozone resistance, UV resistance, weather resistance and aging resistance, ranking first in general rubber. Good electrical insulation, chemical resistance, impact elasticity, acid and alkali resistance, small specific gravity, and high filling coordination. The heat resistance can reach 150 ℃. It is resistant to polar solvents such as ketones and esters, but it is not resistant to aliphatic hydrocarbons and aromatic hydrocarbons. Other physical and mechanical properties are slightly inferior to natural rubber and superior to styrene butadiene rubber. The disadvantage is that self adhesion and mutual adhesion are very poor, and it is not easy to bond. Operating temperature range: about － 50 ℃～ ＋ 150 ℃. It is mainly used for chemical equipment lining, wire and cable sheath, steam hose, heat-resistant transport belt, rubber products for automobiles and other industrial products.

10. Silicone rubber (Q) is a special rubber with silicon and oxygen atoms in the main chain, in which silicon plays a major role. Its main characteristics are high temperature resistance (up to 300 ℃) and low temperature resistance (down to – 100 ℃). It is the best Tuobai cold and high temperature resistant rubber at present; At the same time, it has excellent electrical insulation, high stability to thermal oxidation and ozone, and great chemical inertness. The disadvantages are low mechanical strength, poor oil resistance, solvent resistance, acid and alkali resistance, difficult vulcanization, and expensive price. Operating temperature: － 60 ℃～ ＋ 200 ℃. It is mainly used to make high and low temperature resistant products (rubber tubes, seals, etc.), high temperature resistant wire and cable insulation layer. Because it is non-toxic and tasteless, it is also used in the food and medical industry.

11. Fluoroelastomer (FPM) is an organic elastomer formed by copolymerization of fluorine containing monomers. It is characterized by temperature resistance up to 300 ℃, acid and alkali resistance, oil resistance, radiation resistance and high vacuum resistance; The electrical insulation, mechanical properties, chemical corrosion resistance, ozone resistance and atmospheric aging resistance are excellent. The disadvantages are poor processability, expensive price, poor cold resistance and low elastic permeability. Operating temperature range: － 20 ℃～ ＋ 200 ℃. It is mainly used in the national defense industry to manufacture vacuum resistant, high temperature resistant, chemical resistant sealing materials, rubber hoses or other parts on aircraft and rockets, as well as in the automotive industry.

12. Polyurethane rubber (AU  EU) is an elastomer formed by polymerization of polyester (or polyether) and diisocyanate compounds. It is characterized by good wear resistance and is the best among all kinds of rubber; High strength, good elasticity and excellent oil resistance. Ozone resistance, aging resistance and air tightness are also excellent. The disadvantages are poor temperature resistance, poor water and alkali resistance, and poor resistance to aromatic hydrocarbons, chlorinated hydrocarbons, ketones, esters, alcohols and other solvents. Operating temperature range: about – 30 ℃~+80 ℃. The tire shall be made of parts, washers, shockproof products, and wear-resistant, high-strength and oil resistant rubber products.

13. Acrylate rubber (ACM  AEM) is a polymer of ethyl acrylate or butyl acrylate. It is characterized by good heat resistance and oil resistance, and stable performance in lubricating oil containing sulfur, phosphorus and chlorine additives. At the same time, it has good aging resistance, oxygen resistance, ozone resistance, ultraviolet resistance and air tightness. The disadvantages are poor cold resistance, water resistance, steam resistance, organic and inorganic acids and alkalis. In methanol, ethylene glycol, ketone ester and other water-soluble solutions, the expansion is serious. At the same time, the elasticity and wear resistance are poor, the electrical insulation is poor, and the processing performance is poor. Operating temperature range: about – 25 ℃~+180 ℃. It can be used to manufacture oil resistant, heat resistant and aging resistant products, such as seals, rubber hoses, chemical linings, etc.

14. Chlorosulfonated polyethylene rubber (CSM) is an elastic polymer obtained from chlorination and sulfonation of polyethylene. It has good ozone resistance and weather resistance, superior to other rubbers. Flame retardancy, heat resistance, solvent resistance, resistance to most chemicals and acid and alkali resistance are good. The electrical insulation is acceptable, and the abrasion resistance is similar to that of styrene butadiene rubber. The disadvantages are poor tear resistance and poor processing performance. Operating temperature range: about － 20 ℃～ ＋ 120 ℃. It can be used as the sealing material on the ozone generator to manufacture oil resistant seals, wire and cable sheaths, oil resistant rubber products and chemical linings.

15. Chlorine ether rubber (CO  ECO) is a polymer formed by homopolymerization of epichlorohydrin or copolymerization of epichlorohydrin and ethylene oxide. It is characterized by excellent resistance to aliphatic hydrocarbon and chlorinated hydrocarbon solvents, alkali, water and aging, ozone resistance, weather resistance, heat resistance and high air tightness. The disadvantages are low strength, poor elasticity and poor electrical insulation. Operating temperature range: about – 40 ℃~+140 ℃. It can be used as rubber hose, sealing element, film and container lining, oil tank, rubber roller, oil seal, water seal, etc.

16. Chlorinated polyethylene rubber (CM or CPE) is an elastic polymer made of polyethylene through chlorine substitution reaction. Its properties are similar to those of chlorosulfonated polyethylene rubber, characterized by good fluidity and easy processing; It has excellent weather resistance, ozone resistance, corona resistance, heat resistance, acid and alkali resistance, and oil resistance. The disadvantages are poor elasticity, large compression deformation and low electrical insulation. Operating temperature range: about － 20 ℃～ ＋ 120 ℃. Wire and cable sheath, rubber hose, adhesive tape, rubber roll chemical lining, etc.