CR/Neoprene®
Description:
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.
Common Uses:
CR is found in:
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Thousands of diverse environment, including automotive, wire and cable industries
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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
Properties:
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
Optional Colors:
Production:
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.
Advantages:
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.
Limitations:
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.
Frequently Asked Questions About CR (Neoprene®)
What is CR (Neoprene®)?
CR, also known by the trade name Neoprene®, is a synthetic elastomer first developed in 1931 by DuPont. It is produced from the emulsion polymerization of chloroprene (2-chlorobutadiene) and is known for its balanced combination of mechanical and chemical properties.
Why is Neoprene® considered a versatile elastomer?
Neoprene® offers a well-rounded performance profile: it is resistant to weathering, ozone, oils, and flame, while also providing high durability and physical toughness. This makes it suitable for a wide range of applications.
What industries commonly use CR rubber?
CR is widely used across automotive, wire and cable industries, as well as refrigeration and air-conditioning systems. It is especially common where resistance to oil, heat, abrasion, and flame is required.
What are typical applications for CR gaskets?
CR gaskets are especially used in air-conditioning systems operating with old refrigerants, such as R12 or R22, and lubricants containing mineral oil, where resistance to heat, abrasion, and flame is necessary.
What are the standard temperature ranges for CR?
Standard CR compounds operate between -40°C (-40°F) and 100°C (212°F). High-temperature CR formulations can perform between -55°C (-67°F) and 125°C (257°F).
What hardness range is available for Neoprene® compounds?
CR compounds are available in a hardness range from 30 to 90 Shore A, allowing flexibility in both soft and firm applications.
What are the ASTM designations for CR rubber?
CR is designated as CR under ASTM D1418 and typically classified under BC or BE according to ASTM D2000 specifications.
What colors are available for CR materials?
The standard production color is black, though optional colors may be available depending on manufacturer and batch requirements.
How is CR rubber produced today?
Modern production involves chlorination of butadiene or isoprene. The chloroprene monomer is emulsified in water and polymerized using free-radical initiators. Vulcanization typically uses metal oxides to form crosslinked polymer chains.
What key advantages does CR offer?
CR features high tensile strength, resilience, and strong resistance to oil, flame, oxygen, ozone, and weathering. It performs particularly well when in contact with refrigerants, ammonia, water, silicone oils, and high aniline-point mineral oils.