Specialty rubber Special rubber refers to rubber with certain special properties.
1. Nitrile butadiene rubber NBR: A polymer formed by the copolymerization of butadiene and acrylonitrile through emulsion, the higher the acrylonitrile content, the better the oil resistance, but the cold tolerance decreases accordingly. The general operating temperature range is -25-100 °C. Nitrile butadiene rubber is known for its excellent oil resistance. It can be used for a long time in air at 120°C or in oil at 150°C. The conductivity is relatively good.
It is widely used, mainly used in oil-resistant products, a variety of oil-resistant gaskets, gaskets, sleeves, flexible packaging, soft rubber tubes, printing and dyeing rubber rollers, cable glue materials, antistatic rubber products, etc. It has become an indispensable elastic material in industries such as automotive, aviation, petroleum, and photocopying. All kinds of sealing products, flame retardant products, and phenolic used as structural adhesives,
Advantages: Good resistance to oil, water, solvent and high pressure oil. Good compressibility, elongation, abrasion resistance, aging resistance, air tightness and excellent adhesion properties.
Disadvantages: Not suitable for use in polar solvents, such as ketones, ozone, nitrohydrocarbons, MEK can be blended with natural rubber. Ozone resistance, electrical insulation, and cold resistance are all poor.
2. Hydrogenated nitrile rubber HNBR: Nitrile rubber is made by removing part of the double chain after hydrogenation, and its temperature resistance and weather resistance are much higher than that of general nitrile rubber, and the oil resistance is similar to that of general nitrile rubber. The general operating temperature range is -25-150 °C.
Among the cleaning agents suitable for washing or dishwashing, they are widely used in environmentally friendly refrigerants, seals in R134a systems, and seals in automobile engine systems.
Advantages: better abrasion resistance, excellent corrosion, tensile resistance, tear resistance and compression resistance. It has good resistance to atmospheric conditions such as ozone.
Disadvantages: Not recommended for use in alcohol, ester or aromatic solutions.
3. Silicone rubber Q: The main chain is composed of silicon and oxygen atoms alternately to form the main chain, and the side chain is a carbon-containing group with an organic group on the silicon atom. The largest amount used is silicone rubber with a side chain of ethylene. It is both heat-resistant and cold-resistant, with a service temperature between 100-300°C, and it has excellent weather resistance and ozone resistance as well as good insulation.
Silicone rubber products are biocompatible materials, which are closely related to people’s lives, remote controls, keyboards, POS machines, scanners, mobile phones, electronic dictionaries, mobile phone cases, etc. are all related to silicone rubber. It is mainly used in aviation industry, electrical industry, food industry and medical industry. Colorless silicone rubber products are non-toxic and can be used as artificial organs, used in the beauty industry and physiotherapy industry.
Advantages: high and low temperature resistance, ozone resistance, good electrical insulation.
Disadvantages: low strength, poor tear resistance, poor wear resistance.
4. Fluoroelastomer FKM: Fluoroelastomer is a synthetic polymer with fluorine atoms attached to the carbon atoms of the molecular backbone or side chain obtained by polymerization or polycondensation of fluorine-containing monomers. Due to the different fluoromonomers used, there are many varieties of fluoroelastomers, which can be divided into fluoroolefin copolymers and nitroso copolymers. It is usually expressed by the number of fluorine atoms in the fluorine-containing unit in the copolymer, such as fluoroelastomer 23, which is a copolymer of vinylidene fluoride and chlorotrifluoroethylene. According to the chemical composition, it can be divided into fluoroene fluororubber, fluorosilicone rubber, nitroso fluorofluoroelastomer, fluorinated acrylic rubber, fluorinated phosphonazene rubber, perfluoroether rubber, etc.
It is widely used in modern aerospace, aviation, automobile, petroleum and household appliances and other fields, and is an irreplaceable key material in the cutting-edge industry of national defense.
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: Polycondensation of dihaloalkyl with polysulfides of alkali metals or alkaline earth metals. In addition, there are polyurethane rubber, chlorohydrin rubber, acrylic rubber, etc., which are mostly used in combination with nitrile rubber.
Advantages: Excellent oil and solvent resistance,
Disadvantages: low strength, poor aging resistance, poor processability, odor.
6. Sponge rubber, also known as foam rubber, foam rubber or microporous rubber, is a porous elastic material, which is a general term for various types of rubber with a pore structure. According to the different structure of the porous materials, the holes of this kind of porous materials can be divided into three types: closed pores (the holes are not connected to each other), open pores (the holes and the holes are not completely separated from each other by the hole wall, and have a certain degree of connectivity) and mixed holes (both open and closed cell structures).
Microcellular rubber mainly includes two types: expanded rubber and sponge rubber. Including soft sponge, hard sponge, micro-bubble sponge, conductive sponge, magnetic sponge, water expansion sponge, composite sponge, etc.
Sponge rubber products are widely used in sealing, shock absorption, heat insulation, sound insulation, printing and dyeing and even ion exchange and many other aspects, and are widely used in aviation, automobiles, instruments, meters, home appliances and packaging industries. Its shape has plates, strips, tubes, rollers, washers, etc., with a wide range of specifications and different shapes. Different conditions of use require different hole structures and pore sizes. For this reason, it is required to make corresponding adjustments in the formula and processing technology to achieve the corresponding performance.