1、 Types and characteristics of rubber

A universal rubber

1. Natural rubber NR: made from latex of the three leaf rubber tree, the basic chemical composition is cis polyisoprene, which is a polymer of isoprene.

It is a raw material for making adhesive tape, rubber hose, and rubber shoes, suitable for making shock absorber parts and products used in automotive brake oil, ethanol, and other liquids with hydroxide ions.

Advantages: It has good wear resistance, high elasticity, tensile strength and elongation, acid and alkali resistance, and good comprehensive performance.

Disadvantages: Not heat-resistant, not oil resistant (can tolerate vegetable oil), easily expands and dissolves in mineral oil or gasoline, alkali resistant but not strong acid resistant. It is prone to aging in the air and becomes sticky when exposed to heat.

2. Isoprene rubber IR: The full name is cis-1,4-polyisoprene rubber, a high cis synthetic rubber made from isoprene, produced by solution polymerization. Due to its similar structure and properties to natural rubber, it is also known as synthetic natural rubber.

It can replace natural rubber in manufacturing heavy-duty 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 chemical stability, and superior quality uniformity and processing performance compared to natural rubber.

Disadvantage: The strength of raw rubber (before processing) is significantly lower than that of natural rubber.

SBR (styrene butadiene rubber): produced by copolymerization of butadiene and styrene. It is the general synthetic rubber with the largest output, which can be divided into lotion polymerized styrene butadiene rubber, solution polymerized styrene butadiene rubber and thermoplastic rubber (SBR) according to the production method.

Widely used in the tire industry, footwear industry, fabric industry, and conveyor belt industry.

Advantages: Low cost non oil resistant material, good water resistance, good elasticity when the hardness is below 70, and poor compressibility when the hardness is high. Compared with natural rubber, it has uniform quality, less foreign matter, better wear resistance and aging resistance. Its comprehensive performance and chemical stability are good, and it can be mixed with natural rubber for use.

Disadvantages: The mechanical strength is weak, and it is not recommended to use strong acids, ozone, oils, esters, fats, and most hydrocarbons.

4. Shunding rubber BR: The full name is cis-1,4-polybutadiene rubber, which is obtained by solution polymerization of butadiene.

The vast majority is used for producing tires, with a small portion used for manufacturing cold resistant products, cushioning materials, as well as 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 is easy to be used in combination with natural rubber, chloroprene rubber, nitrile rubber, etc.

Disadvantages: Poor tear resistance and poor wet slip resistance.

5. chloroprene rubber CR: It is mainly made of chloroprene as the raw material, and is copolymerized by homopolymerization or a small amount of other monomers. The vulcanized rubber has good elasticity and wear resistance, and the formula does not contain sulfur, making it very easy to produce. It has particularly good weather resistance, is not afraid of intense twisting, is not afraid of refrigerants, and is resistant to dilute acids and silicone ester lubricants. The general temperature range for use is -50-150 ℃.

Chloroprene rubber has a wide range of applications, such as making transport belts and transmission belts, as a sheath material for wires and cables, manufacturing oil resistant rubber hoses, gaskets, and chemical resistant equipment linings. Produce various parts that come into direct contact with the atmosphere, sunlight, and ozone. Suitable for various fire-resistant and chemically corrosion-resistant rubber products. It is not recommended to use chemical compounds such as strong acids, nitro hydrocarbons, esters, chloroform, and ketones, as well as seals that are resistant to R12 refrigerants and rubber parts or seals on household appliances.

Advantages: It has good comprehensive performance, such as high tensile strength, water resistance, oil resistance, flame resistance, heat resistance, light resistance, aging resistance, oxidation resistance, and ozone resistance. Good elasticity and compression deformation, with resistance to animal and vegetable oils, will not be affected by neutral chemicals such as fats, oils, various oils, and solvents, and has flame retardant properties. High chemical stability.

Disadvantages: High density, easy to crystallize and harden at room temperature, poor storage performance, poor electrical insulation and cold resistance, easy to crystallize and harden at low temperatures, and unstable raw rubber during storage. Not resistant to phosphate ester hydraulic oil. The expansion amount is large in mineral oils with low aniline point.

EPDM rubber: synthesized mainly from ethylene and propylene, with good chemical stability, wear resistance, elasticity, oil resistance, and similar properties to styrene butadiene rubber. Introducing a small amount of a third component with double chains into the EP main chain can be sulfurized to form EPDM, which is generally used at a temperature of minus 50-150 ℃. Excellent resistance to polar solvents such as alcohols, ketones, etc. It has a wide range of applications and can be used as tire sidewalls, rubber strips, inner tubes, and automotive components. It can also be used as wire and cable sheaths, as well as high-voltage and ultra-high voltage insulation materials. Manufacturing light colored products such as rubber shoes and hygiene products. It can be filled with a large amount of oil and carbon black, and the product price is relatively low. It is commonly used as a sealing component or part for high-temperature water vapor environments and bathroom equipment. Rubber components in the braking system. Seals in radiators (car water tanks).

Advantages: It has good weather resistance and ozone resistance, excellent water resistance and chemical resistance, can use alcohols and ketones, is resistant to high temperature steam, and has good impermeability to gases. Excellent heat resistance, aging resistance, ozone resistance, and electrical insulation stability,

Disadvantage: Not recommended for food use or exposure to aromatic hydrocarbons.

7. Butyl rubber IIR: It is polymerized from isobutene and a small amount of isoprene. Due to the steric hindrance of methyl groups, the movement of molecules is less than other polymers, and it is generally used at a temperature range of minus 54-110 ℃.

Commonly used for inner tubes, leather bags, rubber paste paper, window frame rubber, steam hoses, heat-resistant conveyor belts, etc. of car tires.

Advantages: It is impermeable to most gases, highly resistant to heat, sunlight, and ozone, and has good electrical insulation; Has high resistance to polar solvents and can be exposed to animal or vegetable oils or chemicals that can be vaporized.

Disadvantage: It is not recommended to use it together with petroleum solvents, kerosene, and aromatic hydrocarbons.

Special type rubber

Special type rubber refers to rubber with certain special properties.

1. Nitrile rubber NBR: a polymer made from butadiene and acrylonitrile via lotion copolymerization. The higher the acrylonitrile content, the better the oil resistance, but the cold resistance will decrease accordingly. The general temperature range for use is minus 25-100 ℃. Nitrile rubber is known for its excellent oil resistance. Can be used for a long time in air at 120 ℃ or in oil at 150 ℃. The conductivity is relatively good.

Widely used, mainly for oil resistant products, various oil resistant gaskets, washers, sleeves, flexible packaging, flexible rubber hoses, printing and dyeing rubber rollers, cable adhesive materials, anti-static rubber products, etc. It has become an essential elastic material in industries such as automotive, aviation, petroleum, and photocopying. Various sealing products, flame retardant products, and phenolic adhesives used in combination as structural adhesives,

Advantages: It has good resistance to oil, water, solvents, and high-pressure oil. Good compressibility, elongation, wear resistance, aging resistance, airtightness, and excellent bonding performance.

Disadvantages: Not suitable for use in polar solvents such as ketones, ozone, nitro hydrocarbons, MEK can be mixed with natural rubber for use. Ozone resistance, electrical insulation, and cold resistance are all relatively poor.

2. Hydrogenated nitrile rubber HNBR: Nitrile rubber is made by removing some double chains after hydrogenation. Its temperature resistance and weather resistance are much higher than ordinary nitrile rubber, and its oil resistance is similar to that of ordinary nitrile rubber. The general temperature range for use is minus 25-150 ℃.

Suitable for laundry or dishwashing cleaning agents, widely used as environmentally friendly refrigerants, seals in R134a systems, and seals in automotive engine systems.

Advantages: It has good wear resistance, excellent corrosion resistance, tensile resistance, tear resistance, and compression resistance. Has good resistance under atmospheric conditions such as ozone.

Disadvantage: Not recommended for use in alcohol, ester, or aromatic solutions.

3. Silicone rubber Q: The main chain is formed by alternating silicon and oxygen atoms, and the side chains are carbon containing groups with organic groups on the silicon atoms. The maximum usage is for silicone rubber with ethylene side chains. It is both heat-resistant and cold resistant, with a usage temperature between 100-300 ℃. It has excellent weather resistance, ozone resistance, and good insulation properties.

Silicone rubber products belong to biocompatible materials and are closely related to people's lives. Remote controls, keyboards, POS machines, scanners, mobile phones, electronic dictionaries, phone cases, etc. are all related to silicone rubber. Mainly used in aviation industry, electrical industry, food industry, medical industry, etc. Colorless silicone rubber products are non-toxic and can be used as artificial organs in the beauty and therapy industries.

Advantages: High and low temperature resistance, ozone resistance, good electrical insulation.

Disadvantages: Low strength, poor tear resistance, and poor wear resistance.

Fluororubber FKM: Fluororubber is a synthetic polymer with fluorine atoms attached to the carbon atoms of the main or side chains of fluorinated monomers through polymerization or condensation. Due to the different fluorinated monomers used, fluororubber has many varieties, which can be broadly divided into fluorinated olefin copolymers and nitroso copolymers. Usually expressed in terms of the number of fluorine atoms in the fluorinated units of copolymers, such as fluororubber 23, which is a copolymer of vinylidene fluoride and chlorotrifluoroethylene. According to chemical composition, it can be divided into fluorinated rubber, fluorosilicone rubber, nitroso fluorinated rubber, fluorinated acrylic rubber, fluorinated phosphazene rubber, perfluoroether rubber, etc.

It has been widely used in fields such as modern aerospace, aviation, automotive, petroleum, and household appliances, and is an irreplaceable key material in cutting-edge defense industries.

Advantages: It has the characteristics of high temperature resistance, oil resistance, corrosion resistance, oxidation resistance, solvent resistance, flame resistance, chemical resistance, and weather resistance.

5. Polysulfide rubber PSR: It is formed by the condensation of polysulfides of dihalomethanes and alkali metals or alkaline earth metals. In addition, there are polyurethane rubber, chlorohydrin rubber, acrylic rubber, etc., which are often used in combination with nitrile rubber.

Advantages: Excellent oil and solvent resistance,

Disadvantages: Low strength, poor aging resistance, poor processability, and odor.

6. Sponge rubber, also known as foam rubber, foam rubber or microcellular rubber, is a porous elastic material, which is the general name of various rubbers with pore structure. The pores of this type of porous material are distributed throughout the entire material, and according to the different pore structures, they are divided into three types: closed pores (pores that are not connected to each other), open pores (pores that are not completely separated from each other by pore walls and have a certain degree of connectivity), and mixed pores (both open and closed pore structures).

Microporous rubber mainly includes two types: expanded rubber and sponge rubber. Including soft sponge, hard sponge, microbubble sponge, conductive sponge, magnetic sponge, water swelling sponge, composite sponge, etc.

Sponge rubber products are widely used in many aspects such as sealing, shock absorption, heat insulation, sound insulation, printing and dyeing, and even ion exchange. They are widely used in aviation, automotive, instrumentation, home appliances, and packaging industries. Its appearance includes plate, strip, tube, roller, gasket, etc., with various specifications and shapes. Different usage conditions require different hole structures and aperture sizes. Therefore, it is required to make corresponding adjustments in the formula and processing technology to achieve the corresponding performance.

2、 The use of rubber

1. Transportation

The rubber industry has developed alongside the automotive industry. Rubber consumption accounts for a considerable proportion in transportation. Rubber products are indispensable in sea, land, and air transportation. For example, a Liberation brand 4-ton truck requires over 200 kilograms of rubber products, a hard seat carriage requires a total weight of over 300 kilograms of rubber products, a 10000 ton ship requires nearly 10 tons of rubber products, and a jet airliner requires nearly 600 kilograms of rubber. Tires used as transportation vehicles, rubber spring shock absorbers for railway vehicles and cars, and passenger transport belts for large shops, stations, and subways. In addition, there are also "hovercraft" and "hovercraft" made of rubber.

2. Industrial mines

The industrial sector requires a large quantity of rubber products of various sizes, with a wide range of varieties and applications, some of which have special requirements. The main products include adhesive tape, rubber hose, sealing gasket, rubber roller, rubber plate, rubber lining, and labor protection equipment. In industries such as mining, coal, metallurgy, etc., tape, steel wire rope core conveyor belts, or synthetic fiber conveyor belts are used to transport finished products. The rubber lining of the mining mill, using forged rubber instead of manganese steel, has increased its service life by two to four times and reduced noise. This product has been promoted worldwide.

3. Agriculture, forestry and water conservancy

In addition to various tires used for tractors and agricultural machinery, the rubber tracks required for combine harvesters, rubber anti-seepage layers and dams used for irrigation water tanks and reservoirs, rubber boats, life-saving supplies, etc. are all increasing in usage. Rubber accessories are also available in agricultural and sideline product processing equipment, forestry, animal husbandry, and fishery technology equipment. A Tieniu-40 wheeled tractor requires as many as 121 rubber products. With the great development of agricultural mechanization and agricultural water conservancy, there will be an increasing demand for rubber products.

4. Military and National Defense

Rubber is an important strategic material and is widely used in military defense. It has a footprint in military equipment, air force facilities, and defense engineering. For example, a tank requires over 800 kilograms of rubber; A 30000 ton warship requires 68 tons of rubber, and there are also many types of ships, tents, warehouses, protective equipment, shower clothing, and other items made of rubber. As for the rubber products with special properties such as high temperature resistance, low temperature resistance, oil resistance, and high vacuum resistance required for cutting-edge national defense technology, they are indispensable. With the development of national defense modernization, rubber with special properties that can withstand temperatures ranging from minus 100-400 ℃ and resist various acids, alkalis, and oxidants is being developed and produced.

5. Civil and Architectural Engineering

The machinery, transportation equipment, protective equipment, etc. used in construction all have rubber accessories. For example, glass window sealing rubber strips used in buildings, soundproof flooring, soundproofing sponges, rubber carpets, rainproof materials, and emulsion coatings. Install large rubber spring seat cushions to reduce the vibration and noise caused by the subway, and alleviate the damage of earthquakes to buildings. Mixing latex into cement can improve its elasticity and wear resistance. Adding 3% rubber or latex to asphalt for paving road surfaces can prevent cracking and improve impact resistance.

⒍ Electrical communication

Another characteristic of rubber is its good insulation performance and low conductivity. Various wires and cables are often made of rubber. Hard rubber is also commonly used to make rubber hoses, rubber rods, rubber plates, separators, and battery cases. In addition, it is widely used as protective equipment such as insulated gloves, insulated rubber boots, and shoes.

7. Medical and health care

There are many rubber products used in the medical and health sector, such as various rubber hoses in hospitals, surgical gloves, ice packs, sponge seat cushions, etc., which are mostly rubber products. Rubber products are also used as accessories for medical equipment and instruments. Medical rubber products often have special requirements such as non toxicity, sterilization, physiological inertness, and radiation resistance. Butyl rubber has high biological inertness, chemical stability, and slight permeability, which can be used to process rubber bottle stoppers and ensure the preservation of high moisture absorption, antibiotics, and anti-cancer agents. There has been great progress in using silicone rubber to manufacture artificial organs and human tissue substitutes. It is also used to make drug capsules, which are placed in appropriate positions in the body to slowly and continuously release the drugs inside the capsules. This can improve the efficacy and is relatively safe.

⒏ Storage of goods

Rubber film is widely used for regulating the storage of fruits and vegetables. Silicone rubber has superior breathability and appropriate permeability to CO2 and O2. According to the differences in respiratory intensity and quantity of different fruits and vegetables, various sizes of silicone rubber air bags are made to maintain an appropriate amount of CO2 inside the bag, forming a good gas storage environment, thereby inhibiting the respiratory intensity of fruits and vegetables, delaying metabolic rate, delaying the ripening process of fruits and vegetables, reducing water evaporation, and preventing decay.

9. Culture, education, and sports

Common types of ball shells, table tennis racket sponge rubber surfaces, swimming fins, toy balls, gold pen shells, erasers, rubber balls, rubber strings, rubber seals, rubber blankets, balloons, and sponge rubber pads are widely used in cultural and educational institutions, offices, design and drawing, and sports equipment.

⒑ Daily necessities

There are many rubber products serving us in daily life, widely worn by urban and rural residents. It is a type of rubber product with a large consumption volume. Such as raincoats, rubber shoes, hot water bottles, elastic bands, children's toys, sponge seat cushions, and latex impregnated products.


Huali Chemical Properties of Various Types of Rubber