ECTFE/Halar® Coatings Review
ECTFE or Ethylene-Chlorotrifluoro-Ethylene is produced under the trade name Halar®. ECTFE is a copolymer of ethtlene and chlorotrifluoroethene. Typically the material is applied as coating for protection against caustic chemicals and abrasion resistance. ECTFE is applied by spray or dipping.
ECTFE is resistant to the permeation of oxygen, carbon dioxide, chlorine gas, and hydrochloric acid and is generally considered superior to PTFE or FEP. Water absorption by ECTFE is less than 0.1% by volume.
ECTFE is used to minimize wear in high-friction applications, where dimensional stability is a requirement.
Some typical applications include bearings, cams, valve seats, semiconductor tooling and wire and cable. It is used as a bearing surface for machine tool ways. It is also used in electrical insulators due to its high resistivity and low dielectric constant.
ECTFE is commonly available as sheets, bars, rods and nonwoven rollgoods. It may be bonded using the same type of epoxy resin or ultrasonics as other fluoropolymers.
ECTFE can be melt blown into a nonwoven fabric. The resultant fine fibers having the same low reactivity as Halar but important characteristics due to the high surface area and porosity. Such applications include filters for highly reactive acids or alkalis even at elevated temperatures, coalescing of oil from water using the high surface energy or battery separators. Another unique application of strips of Halar web is to produce a Halar veil that can be used to construct pipes or valves for use in corrosive environments such as chloro-alkalis facilities.
In many ways the chemical properties resemble PTFE but with lower melting point (and higher price)
ECTFE is relatively unaffected by all common chemicals encountered within industry., including minerals and oxidizing acids, alkalies, metal etchants, liquids oxygen and solvents. Coatings thickness are typically specified at 0.010 to 0.045 inch thick with a temperature range from 320 degrees F (160C).
Ethylene-Chlorotrifluoro-Ethylene (ECTFE) Coating Characteristics
|Tensile Strength (ASTM D1708)||6600 psi|
|Elongation (ASTM D256)||325%|
|Impact Strength (ASTM D256)||no break|
|Dielectric Strength (ASTM D149)||2000 volts per mil|
|Use Temperature||310°F max|
|Chemical Resistance (ASTM D543)||Excellent|
|Water Absorption (ASTM D570)||< .1%|
|Thickness||.020" - .040"|
|Specific Gravity||1.68± .05|