World Library  
Flag as Inappropriate
Email this Article

Viton

Article Id: WHEBN0000842163
Reproduction Date:

Title: Viton  
Author: World Heritage Encyclopedia
Language: English
Subject: Ozone cracking, DuPont, Thermoplastics, Aviation biofuel, Head gasket
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Viton

Genuine Viton

Viton is a brand of synthetic rubber and fluoropolymer elastomer commonly used in O-rings, chemical-resistant gloves, and other molded or extruded goods. The name is a registered trademark of DuPont Performance Elastomers L.L.C..

Viton fluoroelastomers are categorized under the ISO 1629 designation of FKM. This class of elastomers is a family comprising copolymers of hexafluoropropylene (HFP) and vinylidene fluoride (VDF or VF2), terpolymers of tetrafluoroethylene (TFE), vinylidene fluoride (VDF) and hexafluoropropylene (HFP) as well as perfluoromethylvinylether (PMVE) containing specialties. The fluorine content of the most common Viton grades varies between 66 and 70%.

Varieties

There are four families of viton polymers:

  1. A (Dipolymers of VF2/HFP): General purpose sealing. Automotive, Aerospace fuels & lubricants. Nominal polymer fluorine content: 66%.
  2. B (Terpolymers of VF2/HFP/TFE): Chemical Process plant, Power Utility Seals & Gaskets. Nominal polymer fluorine content: 68%.
  3. F (Terpolymers of VF2/HFP/TFE): Oxygenated Automotive fuels. Concentrated aqueous inorganic acids, water, steam. Nominal polymer fluorine content: 70%.
  4. Specialty types include GLT, GBLT, GFLT & Viton Extreme (Copolymers of TFE/Propylene and Ethylene/TFE/PMVE): Automotive, Oil Exploration, Special Sealing & Ultra Harsh

Applications

The performance of fluoroelastomers in aggressive chemicals depends on the nature of the base polymer and the compounding ingredients used for molding the final products (e.g. O-rings). This performance can vary significantly when end-users purchase Viton polymer containing rubber goods from different sources. Viton is generally compatible with acetic acid. O-rings made of Viton are typically color-coded as black, but new gaskets, seals and O-rings should be green FKM or black FKM, but with a green mark on the outer edge.

Viton O-rings have been used safely for some time in SCUBA diving by divers using gas blends referred to as Nitrox. Viton is used because it has a lower probability of catching fire, even with the increased percentages of oxygen found in Nitrox. It is also less susceptible to decay under increased oxygen conditions.

Viton tubing or Viton lined hoses are commonly recommended in automotive and other transportation fuel applications when high concentrations of biodiesel are required. Studies indicate that types B and F (FKM- GBL-S and FKM-GF-S) are more resistant to acidic biodiesel. (This is biodiesel fuel that is unstable and oxidising.)

Viton o-rings are an alternative to Buna-N seals in BMW's automobile engine variable timing units, known as VANOS. In the VANOS, the Buna-N o-rings deteriorate. The Viton fluorocarbon o-rings have similar functional characteristics to Buna-N, but with much higher temperature and chemical resistance characteristics.

Viton/butyl gloves are highly impermeable to many strong organic solvents that would destroy or permeate commonly used gloves (such as those made with nitriles).

Precautions

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.