Top elastomers for gasket & seal applications

Top elastomers for gasket & seal applications

What are elastomers?  The time period derives from “elastic”-one of the elemental properties of rubber.  The phrases “rubber” and “elastomer” are used interchangeably to check with polymers with viscoelasticity-commonly known as “elasticity.”  The inherent properties of elastomers embody flexibility, excessive elongation and a mix of resilience and damping (damping is a property of rubber that causes it to transform mechanical power to warmth when subjected to deflection).  This distinctive set of properties makes elastomers a really perfect materials for gaskets, seals, isolators, and the like.

Through the years, elastomer manufacturing has migrated from pure rubber yielded from tree latex to extremely engineered rubber compounding variations.  In creating these variations, particular properties are attained with the assistance of components equivalent to fillers or plasticizers or by various content material ratios throughout the copolymer construction.  The evolution of elastomer manufacturing creates a myriad of elastomer prospects that may be engineered, manufactured and made out there throughout the market.

To be able to select the proper materials, one ought to first study the widespread standards for elastomer efficiency in gasket and seal functions.  When choosing an efficient materials, engineers will typically should take a large number of things into consideration.  Service circumstances equivalent to working temperature vary, environmental circumstances, chemical contact, and mechanical or bodily necessities all have to be fastidiously thought-about.  Relying on the applying, these service circumstances can significantly have an effect on efficiency and life expectancy of an elastomer gasket or seal.

With these notions in thoughts, let’s study 5 of probably the most generally employed elastomers for gasket and seal functions.

1) Buna-N/Nitrile/NBR

All synonymous phrases, this artificial rubber copolymer of acrylonitrile (ACN) and butadiene, or Nitrile butadiene rubber (NBR), is a well-liked selection that’s typically specified when gasoline, oil and/or greases are current.

Most important Properties:

  • Max Temperature Vary from ~ -54°C to 121°C (-65° – 250°F).
  • Excellent resistance to oils, solvents and fuels.
  • Good abrasion resistance, chilly stream, tear resistance.
  • Most popular for functions with Nitrogen or Helium.
  • Poor resistance to UV, ozone, and weathering.
  • Poor resistance to ketones and chlorinated hydrocarbons.

Most Typically Utilized in:

  • Aerospace & Automotive Gasoline Dealing with Purposes

Relative Price:

  • Low to Reasonable

2) EPDM

The composition of EPDM begins with the copolymerization of ethylene and propylene. A 3rd monomer, a diene, is added in order that the fabric could be vulcanized with sulfur. The yielded compound is named ethylene propylene diene monomer (EPDM).

Most important Properties:

  • Max Temperature Vary from ~ -59°C to 149°C (-75° – 300°F).
  • Wonderful warmth, ozone and climate resistance.
  • Good resistance to polar substances and steam.
  • Wonderful electrical insulating properties.
  • Good resistance to ketones, abnormal diluted acids, and alkalines.
  • Poor resistance to oils, gasoline, and kerosene.
  • Poor resistance to aliphatic hydrocarbons, halogenated solvents, and concentrated acids.

Most Typically Utilized In:

  • Refrigerated/Chilly-Room Environments
  • Automotive Cooling System and Climate-Stripping Purposes

 Relative Price:

  • Low – Reasonable

three) Neoprene

The neoprene household of artificial rubbers is produced by the polymerization of chloroprene and is often known as polychloroprene or Chloroprene (CR).

Most important Properties:

  • Max Temperature Vary from ~ -57°C to 138°C (-70° – 280°F).
  • Wonderful influence, abrasion and flame resistant properties.
  • Good tear resistance and compression set.
  • Wonderful water resistance.
  • Good resistance to reasonable publicity to ozone, UV, and weathering in addition to oils, greases, and gentle solvents.
  • Poor resistance to sturdy acids, solvents, esters, and ketones.
  • Poor resistance to chlorinated, fragrant, and nitro-hydrocarbons.

Most Typically Utilized In:

  • Aquatic Atmosphere Purposes
  • Digital

Relative Price:

Low

four) Silicone

Silicone rubbers are high-polymer vinyl methyl polysiloxanes, designated as (VMQ), that carry out very properly in difficult thermal environments.  As a consequence of their purity, silicone rubbers are notably properly suited to hygienic functions.

Most important Properties:

  • Max Temperature Vary from ~ -100°C to 250°C (-148° – 482°F).
  • Wonderful excessive temperature resistance.
  • Excellent UV, ozone and climate resistance.
  • Reveals one of the best low temperature flexibility of the supplies listed.
  • Excellent dielectric properties.
  • Poor tensile energy and tear resistance.
  • Poor resistance to solvents, oils, and concentrated acids.
  • Poor resistance to steam.

Most Typically Utilized In:

  • Meals & Beverage Purposes
  • Pharmaceutical Atmosphere Purposes (Besides steam sterilization)

Relative Price:

Reasonable – Excessive

5) Fluoroelastomer/Viton®

Viton® fluoroelastomers are categorized below the Plastic Mold designation FKM.  This class of elastomers is a household comprised of copolymers of hexafluoropropylene (HFP) and vinylidene fluoride (VDF or VF2).

 

Terpolymers of tetrafluoroethylene (TFE), vinylidene fluoride (VDF) and hexafluoropropylene (HFP) in addition to perfluoromethylvinylether (PMVE) containing specialties are noticed in superior grades.

 

FKM is named the answer of selection when excessive temperature in addition to chemical resistance is required.

Most important Properties:

  • Max Temperature Vary from ~ -30°C to 315°C (-20° – 600°F).
  • Finest excessive temperature resistance.
  • Excellent UV, ozone and climate resistance.
  • Poor resistance to ketones, low molecular weight esters.
  • Poor resistance to alcohols and nitro-containing compounds
  • Poor resistance to low temperature.

Most Typically Utilized In:

  • Aquatic/SCUBA Sealing Purposes
  • Automotive Gasoline Purposes with Excessive Concentrations of Biodiesel
  • Aerospace Seal Purposes in Help of Gasoline, Lubricant, and Hydraulic Techniques

Relative Price:

Excessive

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