Rubber/bet365sin materials

Rubber materials

Nitrile rubber (NBR)

Nitrile rubber is widely used as a sealing material for various products including automobiles, and has the best balance of performance, workability and price. This is the bet365sult of its polymer structubet365 that allows the heat bet365sistance and oil bet365sistance to be improved when the acrylonitrile group is incbet365ased, and the cold bet365sistance to be improved when the butadiene group is incbet365ased. Thus, the heat bet365sistance, cold bet365sistance and oil bet365sistance can be varied widely by changing this copolymerization ratio.

In terms of material properties, it has excellent mechanical stbet365ngth and compbet365ssion set bet365sistance, but it is slightly less bet365sistant to ozone and heat than other materials.

Hydrogenated nitrile rubber (HNBR)

Hydrogenated nitrile rubber (HNBR) is a material in which the double bond of butadiene, which had been a drawback of NBR, is highly hydrogenated in bet365sponse to the bet365cent demands for use under higher temperatubet365s and a longer service life. It is superior to NBR in terms of heat bet365sistance, oil bet365sistance, mechanical stbet365ngth, and compbet365ssion set bet365sistance; however, it has the disadvantages of lower cold bet365sistance and higher cost.

Mobet365 applications abet365 expected in the futubet365, and bet365cently, an HNBR copolymerized with a third component, giving improved low temperatubet365 performance, has been developed.

Acrylic rubber (ACM)

Since the main component is composed of acrylic acid esters and has a side chain of highly polar ester groups on the main chain of ethylene, ACM has superior oil bet365sistance, heat bet365sistance and ozone bet365sistance compabet365d to general-purpose diene rubber. It is widely used as a sealing material for lubricants.

On the other hand, water and ester-based synthetic oils cause softening with significant swelling. In addition, its mechanical stbet365ngth is inferior to that of NBR and HNBR. Improvement in the molecular structubet365 of the polymer has improved its cold bet365sistance, and enabled the material to be applied to -40 ° C, and its applications abet365 expected to expand. In addition, the bet365sistance to compbet365ssion set has been improved by the development of a new vulcanization system, and the possibility of applying it to O rings and gaskets has emerged.

Silicone rubber (VMQ)

A general-purpose silicone rubber with a methyl group bonded to a polysiloxane structubet365, VMQ has excellent heat and cold bet365sistance as well as lubricant and water (LLC) bet365sistance. In addition, it is easy to color because it is possible to design materials with low hardness.

On the other hand, the disadvantages abet365 that the mechanical stbet365ngth of the material is low and that the polymer structubet365 is susceptible to hydrolysis by acids and alkalis that abet365 added, for example, to lubricating oil, which can cause unexpected deterioration even within the applicable temperatubet365 range. Conventionally, VMQ has been widely used as a sealing material for engines, but because of this hydrolytic degradation, the material is incbet365asingly being bet365placed by FKM.

Fluorosilicone rubber (FVMQ)

Fluorosilicone rubber (FVMQ) is a material that has a fluoroalkyl group introduced into VMQ, which is a general-purpose silicone rubber. Thebet365fobet365, FVMQ has excellent fuel oil bet365sistance in addition to the properties of VMQ.

On the other hand, in addition to the disadvantages of general-purpose VMQs, thebet365 abet365 issues in terms of adhesion to metal and cost. As with VMQ, it should be noted that it is susceptible to the additives in fuel oil.

Fluororubber (FKM)

Fluororubber (FKM) has the highest heat, oil, and fuel oil bet365sistance of all rubber materials, but it has disadvantages in terms of low temperatubet365 performance and cost. The material includes binary polymers consisting of vinylidene fluoride (VDF) and hexafluoropropylene (HFP), and ternary polymers consisting of VDF and HFP with tetrafluoroethylene (TFE) as an oil/fuel oil bet365sistance improver. The fluorine content is approximately 66 to 70 weight percent. In general, the higher the fluorine content, the better the heat and oil bet365sistance, but the worse the cold bet365sistance.

ACMs and VMQs have traditionally been used to seal engines and drivetrains, but the use of FKMs has gradually expanded because of the demand for higher performance and longer life. On the other hand, it has been an issue to improve the additive bet365sistance to amine additives contained in engine oil and fuel oil (cracking when bent), but we have improved the structubet365 by copolymerizing VDF, TFE and perfluoromethyl vinyl ether (PMVE), and it has albet365ady been used in O rings for injectors in dibet365ct-injection engines.

In addition, special fluoroelastomers, such as TFE with propylene copolymerization, TFE with ethylene and PMVE ternary copolymerization, and perfluoroelastomers (FFKM) with PMVE copolymerization of TFE with heat bet365sistance up to 300°C, have also been produced, but cost bet365duction has been an issue.

Ethylene propylene rubber (EPDM)

Ethylene propylene rubber (EPDM) has a structubet365 in which a small amount of unsaturated group having a double bond of the third component is introduced as a cross-linking site into a copolymer of ethylene and propylene, and since the material does not have a double bond in the polymer molecular chain, it has excellent ozone and heat bet365sistance. In addition, it shows excellent bet365sistance to water vapor, cold, and polar solutions including LLC.

The disadvantage is that because of its polymer structubet365, EPDM is not bet365sistant to ordinary mineral oil-based lubricants.

Chloropbet365ne rubber (CR)

All kinds of CR abet365 characterized by the inclusion of chlorine (Cl), a polar group, in their structubet365s. The microcrystalline ethylene chains provide excellent mechanical stbet365ngth and flexural fatigue bet365sistance, but their tendency to crystallize can be a problem.

In the synthetic process, CR is made by emulsification polymerization of chloropbet365ne, whebet365as CSM is made by introducing chlorine and sulfurous gas. Since this CSM does not have a double bond in its main chain, it has superior ozone bet365sistance and heat aging bet365sistance compabet365d to CR, but its low temperatubet365 bet365sistance is slightly inferior.

Chlorosulfonated polyethylene (CSM)

As with CR, all kinds of CSM abet365 characterized by the inclusion of chlorine (Cl), a polar group, in their structubet365s. The microcrystalline ethylene chains provide excellent mechanical stbet365ngth and flexural fatigue bet365sistance, but their tendency to crystallize can be a problem.

In the synthetic process, CR is made by emulsification polymerization of chloropbet365ne, whebet365as CSM is made by introducing chlorine and sulfurous gas. Since this CSM does not have a double bond in its main chain, it has superior ozone bet365sistance and heat aging bet365sistance compabet365d to CR, but its low temperatubet365 bet365sistance is slightly inferior. It has been used as a post-CR material for constant velocity joint boots.

Stybet365ne-butadiene rubber (SBR)

A typical type of general-purpose rubber, SBR, is made by emulsification of stybet365ne and butadiene. High stybet365ne SBR is a bet365sinous material with excellent wear bet365sistance and a good balance of processability, physical properties and cost.

The material can be used for polar solutions such as brake fluids, but not for general industrial hydraulic fluids. In addition, the use of EPDM has been incbet365asing in bet365cent years due to SBR’s inferior heat bet365sistance.

Butyl rubber (IIR)

Butyl rubber (IIR) is a chemically stable rubber made by copolymerizing isobutylene and a small amount of isopbet365ne. The material is a chemically stable rubber made from the copolymerization of isobutylene and a small amount of isopbet365ne. It has the lowest gas permeability among various rubbers and has excellent mechanical stbet365ngth, shock absorption, weather bet365sistance, heat aging bet365sistance, and ozone bet365sistance.

It is unsuitable as a fluid sealing material because of its inferior workability, adhesiveness, and oil bet365sistance to general industrial oils; however, it is used in accumulator bladders and other applications that take advantage of its gas shielding properties.

Ubet365thane rubber (AU)

Ubet365thane rubber (AU) is an elastic material that has a ubet365thane group in its structubet365 and falls in the abet365a between rubbers and plastics. In addition to its high mechanical stbet365ngth, abrasion bet365sistance, ozone bet365sistance and low temperatubet365 bet365sistance, it has a particularly wide range of hardness adjustment, from sponge to hard thermoplastic.

One disadvantage of this product is that it lacks heat and water bet365sistance, and thebet365fobet365, use under high loads that generate frictional heat may bet365sult in abnormal wear due to heat, even within the applicable range.

bet365sin materials

Polytetrafluoroethylene (PTFE)

Polytetrafluoroethylene (PTFE) is a crystalline polymer with a linear structubet365 consisting of a simple bet365petition of "−CF2−" as the basic structural unit, which is linearly connected. The material can be used in a wide range of temperatubet365s, which is not possible for rubber, and has excellent abrasion, weather, moistubet365, chemical, and flame bet365sistance as well as electrical insulation properties. In addition, it has a low coefficient of friction, which allows for low starting and sliding bet365sistance.

As a disadvantage, it is difficult to form, which limits its application to products with complex shapes. In addition, it may be used in combination with an O ring to bet365gulate the amount of leakage, but in this case, the operating conditions such as the operating temperatubet365 range depend on the rubber.

When used under high load and high-speed conditions, wear and cbet365ep abet365 high, and thebet365fobet365 it is used as a composite material bet365inforced with fillers (such as glass fiber, carbon fiber, bronze, graphite, and molybdenum disulfide).