Industry News

Introduction of sealant sealant

Views : 65
Update time : 2020-12-07 10:04:40

Rubber is a polymer material with unique mechanical properties, which is mainly manifested as large deformation under low stress and high elasticity that can restore its original shape after deformation.Good compatibility with various media;Various properties of rubber can be adjusted by changing rubber varieties and formulations.

Nitrile butadiene rubber NBR

NBR is formed by copolymerization of acrylics and butadiene, and the concentration of acrylics is 18%~50%. The higher the concentration of acrylics, the better the resistance to petrochemical hydrocarbon fuel oil is, but the lower the low temperature performance is. Generally, the temperature range is -25~120 ℃.Eyeball glue is one of the most commonly used rubber for oil seal and O-ring.

Advantages:

• Excellent resistance to oil, water, solvent and high pressure oils.

• Good compression deflection, abrasion resistance and elongation.

Disadvantages:

• Not suitable for use in polar solvents.

• Used for making fuel tank, lubricating oil tank and rubber parts, especially sealing parts, used in petroleum hydraulic oil, gasoline, water, silicon grease, silicon oil, diester lubricating oil, glycol hydraulic oil and other fluid medium.Can be said to be the most widely used, the lowest cost rubber seals.

 

Hydrogenated nitrile butadiene rubber HNBR

Hydrogenated butadiene rubber is a kind of rubber with double chains removed after hydrogenation. After hydrogenation, its temperature resistance and weather resistance are much better than that of general butadiene rubber. Its oil resistance is similar to that of general Butadiene rubber.The general operating temperature range is -25~150 ℃.

HNBR is widely used in air conditioning refrigeration, automotive engine system seals.

 

Carboxyl butyronitrile rubber XNBR

Carboxyl butadiene nitrile rubber is a polymer containing carboxyl monomer (acrylic acid or methacrylic acid), butadiene and acrylonitrile by floating terpolymerization. Carboxyl butadiene nitrile rubber has higher oil resistance, good wear resistance and heat resistance.Compared with NBR and HNBR, XNBR introduced polar carboxyl groups into the molecular chain, which endowed XNBR with more excellent oil resistance, tear resistance, good wear resistance, heat resistance and aging resistance. 

Mainly used for sealing, oil well rubber products, rubber reciprocating oil seal, sealing ring, gasket, O-ring, leather section, rubber roller, sole, heel, textile equipment and other rubber products.

 

Fluorine rubber FKM

Fluoroelastomers of fluoroelastomers are of various types depending on the fluorine content (that is, the monomer structure).The hexafluoride fluororubber widely used at present was first listed by dupont.Excellent high temperature resistance, excellent chemical resistance, resistance to most oils and solvents (except ketones and esters), weather resistance and ozone resistance;Cold resistance is relatively poor, the general use temperature range is -20~200 ℃.Hua Yi special formula can withstand low temperature to -40 ℃.Fluororubber can withstand heat up to 250 ℃, special formula can withstand high temperature up to 300℃.Resistant to most oils and solvents, especially all acids, aliphatic hydrocarbons, aromatic hydrocarbons and animal and vegetable oils.

Disadvantages: Not recommended for ketones, low molecular weight esters and nitrogen-containing compounds.

Application: • Automotive, locomotive, diesel engine and fuel system.

• Seals for chemical plants.

 

Perfluoroether rubber FFKM

Perfluoroether rubber, also known as perfluorinated rubber, has a wide range of chemical dielectric resistance, its chemical resistance is close to PTFE.It can be attacked by more than 1,800 chemicals, solvents and plasmas.At the same time, it has excellent high temperature resistance.Swelling caused by a chemical medium can cause the O-ring or other seal to expand beyond the space of the groove and the seal to fail.Thermal decomposition of rubber at high temperatures results in seal failure.The Perfluorinated seal can withstand more chemical media and higher temperature offset, to meet the special purpose of the best sealing performance.Perfluorinated seals are mainly used in the semiconductor, valve, oil and gas industries.

 

Ethylene propylene rubber EPDM

Ethylene propylene rubber by ethylene and propylene copolymerization into the main chain is not double chain, so heat resistance, aging resistance, ozone resistance, stability are very excellent, but can not add sulfur sulfur.To solve this problem, a small amount of the third component with double chain is introduced into the EP main chain, and EPDM can be formed by adding sulfur and sulfur. The general operating temperature ranges from -50 ℃ to 150 ℃.Excellent resistance to polar solvents.EPDM has good weather resistance and ozone resistance, excellent water resistance and chemical resistance, high temperature resistance to steam, good impermeability to gas.Ketones can be used.However, it is not recommended for food use or exposure to aromatic hydrogen, seals in high temperature steam environment, rubber zeros in braking (braking) systems, seals in radiator (vehicle water tank).

 

Silicone rubber SIL

Silicone rubber is composed of methyl siloxane, so silicone rubber has excellent heat resistance, cold resistance, dielectric resistance, ozone resistance and atmospheric aging and other properties, silicone rubber outstanding performance is wide use temperature, can be in -60℃ (or lower temperature) to +280℃ (or higher temperature) under the long-term use.But the tensile strength and tear strength of silicone rubber poor mechanical properties, such as the physical and mechanical properties at room temperature is less than most of the synthetic rubber, and in addition to the nitrile silicon, fluorine and silicone rubber, poor general silicone oil resistance, solvent resistance, so the silicone should not be used in normal conditions, but very applicable to many specific occasions.Special silicone rubber can meet the requirements of high tensile strength and tear resistance.

 

Fluorosilicone rubber FVMQ

Fluorosilicone rubber is a kind of fluoroalkyl rubber with side chain.With the introduction of fluorine atom, fluorosilicone rubber has good properties of oil resistance and solvent resistance, and wide temperature resistance of silicone rubber.Fluorine silica gel has good heat resistance, excellent oil resistance and solvent resistance, and good stability at room temperature and high temperature.

 

Neoprene CR

Neoprene is made by polymerization of butene monomers.After vulcanized rubber elastic wear resistance is good, not afraid of direct sunlight, has a particularly good atmospheric aging performance, not afraid of intense distortion, not afraid of dichlorodifluoromethane and ammonia refrigerants, dilute acid, silicone ester lubricating oil, but not resistant to phosphate ester hydraulic oil.It is easy to crystallize and harden at low temperature, and the storage stability is poor, and the expansion volume is large in mineral oil with low aniline point.The general operating temperature range is -50~150 ℃.

Advantages:

• Good elasticity with good compression deformation.

• The recipe contains no sulfur and is therefore very easy to make

• Has anti-animal and vegetable oil properties

• Fire resistance

• Physical properties will not be affected by neutral chemicals, esters, fats, various oil products and solvents.

Disadvantages:

• The use of strong acids, nitrohydrocarbons, esters, chloroform and ketones is not recommended.

• In some refrigerants.

• Rubber parts or seals for household appliances.

• Suitable for making all kinds of parts with direct contact with atmosphere, sunlight and ozone.

• Suitable for all kinds of rubber products resistant to fire and chemical corrosion.

 

Acrylate rubber ACM

Although it is relatively weak in mechanical strength, compression deformation and water resistance, it is formed from Alkyl Ester Acrylate as the main component, which is highly resistant to petrochemical oils, high temperature and weather.The general operating temperature range is -25~170 ℃.It has good anti-oxidation and anti-bending and anti-deformation properties.Suitable for automobile transmission system and power steering wheel.

Disadvantages: not suitable for hot water, brake oil.

Does not have low temperature resistance, not suitable for phosphate, automotive transmission system and power system seals.

 

Polyurethane rubber PU

Polyurethane rubber is made from polyester (or polyether) polymerized with diisocyanate lipids.Its chemical structure is more complex than the general elastic polymer, in addition to the recurrent carbamate group, the molecular chain often contains ester group, ether group, aromatic group and other groups.The UR molecular backbone has high strength and high elasticity due to the hydrogen bond force between it.

• Excellent wear resistance of PU: its wear resistance is the highest of all rubbers.Laboratory test results show that the wear resistance of UR is 3~5 times that of natural rubber, which is often up to 10 times in practical application.

• High strength and good elasticity within the range of Shaw A60 to Shaw A70 hardness.

• Good oil and drug resistance.UR has a low affinity with non-polar mineral oils and is almost impervious to erosion in fuel and mechanical oils, much better than general rubber and comparable to nitrile butadiene rubber.

• Low temperature resistance, ozone resistance, radiation resistance, electrical insulation.

The disadvantage of polyurethane rubber is that it is more swelling in alcohols, esters, ketones and aromatics.

Suitable for high pressure seals and water pipes, wear-resistant and oil-resistant rollers.

 

The above rubber introduction is for reference only. The choice of sealing material is also closely related to the specific operating conditions.

Should be subject to the specific working conditions, welcome to inquire.Other rubbers are not listed.