Chloroprene was one of the first successful synthetic elastomers in 1931 made by Dupont under the trade name Neoprene®. It is prepared by emulsion polymerization of chloroprene, or 2-chlorobutadiene. CR is a multi-purposed elastomer which yields a balanced combination of properties. It has good resistance to sun, ozone, weather and performs well in contact with oils and many chemicals. It also displays outstanding physical toughness and good resistance to fire.
CR is found in:
Thousands of diverse environment, including automotive, wire and cable industries
As gaskets in air condition systems, especially old refrigerated media like R12 or R22, lubricants with mineral oil, where resistance to oil, heat, flame, and abrasion are required
Standard Compound: -40°C (-40°F) to 100°C (212°F)
Special Compound (High temp): -55°C (-67°F) to 125°C (257°F)
Hardness: 30 to 90 Shore A
ASTM D1418 Designation: CR
ASTM D2000 Designation: BC, BE
Standard Colors: Black
In modern production it is obtained by the chlorination of butadiene or isoprene. In order to process chloroprene into rubber, it is emulsified in water and then polymerized through the action of free‑radical initiators. In the resultant polymer chain, the chloroprene repeating unit can adopt a number of structures; the most common istrans-polychloroprene. The molecular interlinking necessary for vulcanizing the polymer to a cured rubber is usually effected through the chlorine atom, often by metal oxides.
Neoprene® is valued for its high tensile strength, resilience, oil and flame resistance, and resistance to degradation by oxygen and ozone. CR performs especially well in refrigerants, ammonia, water, silicone grease and oils, and high aniline point mineral oil.
The high cost of CR limits its use to special-properties applications. CR compounds are susceptible to aromatic hydrocarbons, ketones, esters, ethers, strong oxidizing acids, and chlorinated hydrocarbons.