Classification, comparison and advantages and disadvantages of rubber O-ring materials

Nitrile butadiene rubber NBR

(Nickel Rubber) is made by copolymerization of acrylonitrile and butadiene. The acrylonitrile content ranges from 18% to 50%. The higher the acrylonitrile content, the better the resistance to petrochemical oil hydrocarbon fuel oil, but the low temperature performance becomes worse. The general use temperature range is – 25~100 ℃. Nitrile butadiene rubber is one of the most commonly used rubber for oil seal and O-ring.

advantage:

·It has good characteristics of oil resistance, water resistance, solvent resistance and high pressure oil resistance.

·Good compression deflection, abrasion resistance and elongation.

Disadvantages:

·Not suitable for use in polar solvents, such as ketones, ozone, nitrohydrocarbons, MEK and chloroform· It is used to make 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 media. It can be said that it is the most widely used rubber seal with the lowest cost.

Fluoroelastomer FPM

(Fluoro Carbon Rubber) The rubber containing fluorine in the molecule has various types according to the fluorine content (i.e. monomer structure). At present, the widely used hexafluoride fluororubber was first listed by DuPont under the trade name of “Viton”. High temperature resistance is superior to silicone rubber, with excellent chemical resistance, resistance to most oils and solvents (except ketones and esters), weather resistance and ozone resistance; The cold resistance is relatively poor, and the general use temperature range is – 20~250 ℃. The special formula can withstand low temperature up to – 40 ℃. advantage:

·Heat resistant to 250 ℃

·It is resistant to most oils and solvents, especially all acids, aliphatic hydrocarbons, aromatic hydrocarbons, animal and vegetable oils

Disadvantages:

·It is not recommended to be used in ketones, low molecular weight esters and mixtures containing nitrate· Automobile, locomotive, diesel engine and fuel system.

·Seals for chemical plants.

Silicone rubber SIL

(Silicone Rubber) The main chain of silica gel is composed of silicon (- si-o-si). It has excellent heat resistance, cold resistance, ozone resistance and atmospheric aging resistance. It has good electrical insulation performance. The tensile strength is worse than that of ordinary rubber and has no oil resistance. advantage:

·The tensile strength can reach 1500PSI and tear resistance can reach 88LBS after modulation

·Good elasticity and good compression deflection

·Good resistance to neutral solvents

·Excellent heat resistance

·Excellent cold resistance

·Excellent resistance to ozone and oxide erosion

·Excellent electrical insulation

·Good heat insulation and heat dissipation

Disadvantages:

·It is not recommended to be used in most concentrated solvents, oils, concentrated acids and diluted sodium hydroxide· Seals or rubber parts used in the household appliance industry, such as electric kettles, electric irons, and rubber parts in microwave ovens.

·Seals or rubber parts in the electronic industry, such as mobile phone keys, damping pads in DVDs, seals in cable connectors, etc.

·Seals on various articles in contact with human body, such as water bottles, water dispensers, etc.

EPDM

The main chain of ethylene propylene rubber is not double chain, so the heat resistance, aging resistance, ozone resistance and stability are excellent, but sulfur can not be added. To solve this problem, a small amount of the third component with double chains is introduced into the main chain of EP, which can be converted into EPDM by sulfur addition. The general use temperature range is – 50~150 ℃. It has excellent resistance to polar solvents such as alcohol, ketone, ethylene glycol and phosphate oil.

advantage:

·Good weather resistance and ozone resistance

·Excellent water resistance and chemical resistance

·Alcohols and ketones can be used

·High temperature steam resistance, good impermeability to gas

Disadvantages:

·Not recommended for food use or exposure to aromatic hydrogen· Seals for high temperature steam environment.

·Plumbing equipment seals or parts.

·Rubber parts in the brake (brake) system.

·Seals in radiator (car water tank).

Neoprene CR

(Neoprene, Polychloroprene) is polymerized from chloroprene monomer. The vulcanized rubber has good elasticity and abrasion resistance, is not afraid of direct sunlight, has excellent atmospheric aging resistance, is not afraid of severe distortion, is not afraid of refrigerants such as dichlorodifluoromethane and ammonia, is resistant to dilute acid and silicon ester lubricating oil, but is not resistant to phosphate ester hydraulic oil. It is easy to crystallize and harden at low temperature, with poor storage stability and large expansion in mineral oil with low aniline point. The general temperature range is – 50~150 ℃

advantage:

·Good elasticity and good compression deformation.

·The formula does not contain sulfur, so it is very easy to make

·Resistant to animal and vegetable oils

·The physical properties will not be affected by neutral chemicals, esters, grease, various oils and solvents

·Flame retardant

Disadvantages:

·It is not recommended to use strong acid, nitrohydrocarbon, ester, chloroform and ketone chemicals· R12 refrigerant resistant seals· Rubber parts or seals on household appliances.

·It is suitable for making various parts that directly contact with the atmosphere, sunlight and ozone.

·It is applicable to all kinds of fire and chemical resistant rubber products.

Natural rubber NR

(Natural Rubber) is made of rubber latex collected from rubber trees, which is a polymer of isoprene. It has good wear resistance, high elasticity, breaking strength and elongation. It is easy to age in air, become sticky when heated, expand and dissolve in mineral oil or gasoline, and is resistant to alkali but not strong acid· It is the raw material for making adhesive tape, rubber hose and rubber shoes, and is suitable for making shock absorbing parts and products used in automobile brake oil, ethanol and other liquids with hydrogen radicals.

Hydrogenated butadiene rubber HNBR

(Hydrogenate Nitrile) hydrogenated butadiene rubber is a kind of butadiene rubber in which some double chains are removed after hydrogenation. After hydrogenation, its temperature resistance and weather resistance are much higher than those of ordinary butadiene rubber, and its oil resistance is similar to that of ordinary butadiene rubber. Generally, the temperature range is – 25~150 ℃.

advantage:

·It has better abrasion resistance than butadiene rubber

·Excellent corrosion, tension, tear and compression deflection resistance

·Good resistance to ozone, sunlight and other atmospheric conditions

·Generally, it is applicable to the detergent used for washing clothes or dishes

Disadvantages:

·It is not recommended to be used in alcohols, esters or aromatic solutions· The air conditioning refrigeration industry is widely used as the seal in the environment-friendly refrigerant R134a system.

·Automotive engine system seals.

Butyl rubber IIR

(Butyl Rubber) is polymerized by isobutene and a small amount of isoprene. It has a small amount of unsaturated group for sulfur addition. Because the movement of methyl steric barrier molecule is less than that of other polymers, it has less gas permeability, high resistance to heat, sunlight and ozone, and good electrical insulation; It is resistant to polar solvents such as alcohols, ketones, esters, etc., and the general use temperature range is – 54~110 ℃.

advantage:

·Impermeable to most general gases

·Good resistance to sunlight and ozone

·May be exposed to animal or vegetable oils or oxidizable chemicals

Disadvantages:

·It is not recommended to use together with petroleum solvent, rubber kerosene and aromatic hydrogen· It is used to make rubber parts of chemical resistant and vacuum equipment.

Silicone fluorine rubber FLS

(Fluorinated Silicone Rubber) is a silicone rubber that has been fluorinated. Its general performance has the advantages of both fluororubber and silicone rubber; Its oil resistance, solvent resistance, fuel oil resistance and high and low temperature resistance are good, and the general use temperature is – 50~200 ℃.

advantage:

·It is suitable for special purposes, such as resisting the corrosion of oxygenated chemicals, aromatic hydrogen containing solvents and chlorine containing solvents.

Disadvantages:

·It is not recommended to be exposed to brake oil, ketone and callus solution.