The rubber can be divided into natural rubber and rubber. Natural rubber first derived from hevea, when this kind of rubber skin was cut open, will flow out milky juice, called latex, latex agglutination, washing, molding, drying for a quick natural rubber. Of rubber is made by is composed of artificial way, choose different material (monomer) can form the different types of rubber. From 1900 to 1910 the chemist C.D. Harris (Harris) determination of the structure of the natural rubber is isoprene polymer, it is to pioneer the way of artificial rubber. 1910 Russian chemist SV Lebedev (Jeff Lebedev, 1874-1934) with sodium metal to cause agent made of 1, 3 - butadiene poly sodium butyl rubber, later, for the appearance of many new kinds of rubber, butadiene rubber, neoprene, styrene-butadiene rubber and so on. Of rubber production has been far ahead of natural rubber, during which output is the largest styrene-butadiene rubber.
Tires and usually industrial rubber products. General rubber demand is big, is of the first type of rubber.
Rubber shoes and so on. Defects butadiene rubber tearing resistance function is a job, owe good resistance to wet function.
Oil resistance and styrene butadiene rubber. Ethylene propylene rubber USES is very wide, can be used as a tire side, strip, tube and car parts, still can make electrical wiring, cable sheathing, high pressure and ultrahigh pressure of insulating material. Still can make rubber shoes, sanitary products and other light products.
Hose, washer, and resistance to chemical corrosion of equipment material.
Throughout the construction of the rubber. Because of large molecular weight, under the action of external force, a group that fine. When the external force, removal of the external force, fine degree of the fetters of attack change, rebound, molecular chain attack intense tendency of recovery occurs, which is the origin of the high elastic rubber.
Branched structure: rubber macromolecule collection of branched chain, forming gel. Gel function and processing of rubber. , mixing with various additives often gel area, forward part blank, constitute the reinforcing and crosslinking, into a thin part of the product.
Crosslinking structure: linear molecules after some atoms or groups of atoms Bridges connected to each other, constitute a three-dimensional network structure. Followed the vulcanization process, this kind of structure strengthening. So, chain segments free ability is reduced, plasticity and elongation is reduced, strength, elasticity and hardness increase, tightening permanent deformation and swelling degree reduced.
The classification of the rubber material defects and purpose
Natural Rubber (NR (Natural Rubber)
Made of rubber latex collection is isoprene polymer. Has excellent wear resistance, high elasticity, breaking strength and elongation. Easy aging in the air, and become sticky, when it is heated in mineral oil or gas easy swelling and dissolving, alkali resistant, but not resistant to strong acid. Strengths: good elasticity, resistance to acid and alkali. Defects: no weather resistance, no oil resistant (resistant to vegetable oil) is a manufacturer of adhesive tape, rubber hose, rubber shoes material, and is suitable for manufacturing suspension parts, in the car brake oil, such as ethanol with hydroxy of finished product used in the liquid.
Styrene Butadiene rubber SBR (Styrene Butadiene Copolymer)
Butadiene and styrene polymers, in contrast to natural rubber, uniform quality, less foreign body, has the very good abrasion resistance and aging resistance, but the mechanical strength is weak, can be mixed with natural rubber. Advantages: low capital of oil resistance material, excellent water resistance, hardness below 70 outstanding elasticity and high hardness less tight, defect: not advocate using acid, ozone, oil, oil of ester and fat, and most of the hydrocarbons. Widely used in tyre industry, footwear, channgzhou and conveyor belt, etc.
Butyl Rubber (IIR (Butyl Rubber)
For isobutylene and a handful of isoprene polymerization, because of the methyl stereo interferes with less exercise than other polymer molecules, so the gas permeability is less, to heat, sunlight, ozone resistance, good electrical insulation; Resistance to polarity fluxing agent, usually the use of the scale of temperature for 54-110 ℃. Strength: for most often gas impermeability, outstanding resistance to sunlight and odor can be exposed to animal or vegetable oils or gasification of chemicals. Defects: no and solvent oil, heat the oil and aromatic hydrogen were applied for car tyre inner tubes, window frame, rubber, leather, rubber paste paper, steam hose, heat resistant conveyor belt, etc
Hydrogenated Nitrile butadiene rubber HNBR (Hydrogenate Nitrile)
Hydrogenated nitrile butadiene rubber for nitrile butadiene rubber in part by hydrogenation to remove the double chain, its temperature resistance, weatherability than usual after hydrogenated nitrile butadiene rubber improved a lot, oil resistance and usually butyronitrile nearby. Usually the use of the scale of temperature for 25 ~ 150 ℃. Strengths: the butyronitrile has better abrasion resistance, with excellent corrosion resistance, tensile, tearing and characteristics of the tight
Ozone in the atmosphere such as cases, with outstanding resistance, usually applies to laundry or dishwashing detergent. Defects: not advocating applied to alcohol, ester or aromatic solution Air conditioning ZhiLengYe, widely used in environmental protection refrigerant R134a has a system of the seal.
Seal car engine system.
3-20 EPDM (Ethylene propylene Rubber)
Composed of ethylene and propylene copolymerization, and heat resistance, aging resistance, ozone resistance, stability are all very good, but can't sulfur to sulfur. To deal with this question, in the main chain of the EP import a few double chain of the third component and additive sulphur namely into EPDM, usually the use of temperature is 50 ~ 150 ℃. The polarity solvent such as alcohol, ketone excellent resistance Strengths: outstanding weathering resistance and ozone resistance, excellent water resistance and resistance to the word, can use alcohols and ketones, high-temperature steam, excellent impermeability to gas. Defects: no claim for food use or show in aromatic hydrogen. Seal of high temperature steam bath equipment seals or parts. The brake (braking) system of rubber parts. The seals in the radiator tank (cars).
Nitrile butadiene Rubber NBR (Nitrile Rubber)
Composed of propylene eyes and butadiene copolymerization, propylene eyes content by 18% ~ 18%, propylene eyes content is higher, the petrochemical oil hydrocarbon fuel oil resistance is better, but low temperature function is poor, often using the scale of temperature is 25 ~ 100 ℃. Nitrile butadiene rubber for oil seal and now one of the most commonly used rubber o-rings Strengths: excellent oil resistance, water resistance, solvent resistance and resistance to high pressure oil properties
Provide outstanding contractionary, anti-wear and elongation.
Defect: not suitable for polar solvent, such as ketones, ozone, nitro hydrocarbon, MEK and chloroform.? Used in the manufacture of smooth fuel tank, fuel tank and oil in the hydraulic oil, gasoline, oil, silicone oil, two ester is smooth water and other fluid medium use rubber parts, especially is sealing parts. Is now the most widely use, the lowest capital of rubber seals
Neoprene CR (Neoprene, Polychloroprene)
Composed of chloroprene monomer polymerization. After the vulcanization rubber elasticity good abrasion resistance, not afraid of the sun shining directly, have exceptionally good weather resistance function, does not fear the severe distortion, not afraid of refrigerants, and resistance to dilute acid, silicon ester oil is smooth, but not resistant to phosphate series hydraulic oil. At low temperature, easy to crystallization, sclerosis storage stability is poor, the aniline point low expansion of a large number of mineral oil. Usually the use of the scale of temperature for 50 ~ 150 ℃. Strength: elastic and outstanding outstanding contraction deformation, formula does not contain sulfur and thus it is easy to make. Resistant to the characteristics of animal and vegetable oils by neutral chemicals, fat, a variety of oil, grease, solvents and impact property, flameproof feature
Defect: I don't advocate using acid, nitro hydrocarbons, esters, chloroform and ketone of chemicals The seals of refrigerant R12, appliances or seals on the rubber parts. Suitable for manufacturing various directly touch the air, sunlight, ozone parts. Suitable for all kinds of flame retardant, resistance to chemical corrosion of rubber products.