Chloroprene Rubber (CR): Advanced Synthetic Elastomer for High-Performance Applications
Overview
Chloroprene rubber (CR), also known as polychloroprene or neoprene, is a versatile synthetic elastomer produced through the polymerization of 2-chloro-1,3-butadiene monomer (CH₂=CCl-CH=CH₂). This specialty rubber combines excellent mechanical properties with superior chemical resistance and flame retardancy, making it indispensable across diverse industrial applications including automotive sealing systems, construction materials, wire insulation, and high-performance adhesives.
CR is primarily manufactured via emulsion polymerization, where chloroprene monomer droplets are dispersed in an aqueous phase using surface-active agents at pH 10-12. Free-radical catalysts initiate polymerization at temperatures of 20-50°C, with the process terminated by adding antioxidants and stabilizing agents. The polymer backbone contains alternating carbon-carbon double bonds with pendant chlorine atoms, typically exhibiting 85-90% trans-1,4 configuration and 10-15% cis-1,4 configuration.
Leading international manufacturers produce CR under various trade names including DuPont (USA) with their Neoprene® series, DOW Chemical (USA), Asahi Kasei (Japan) with their Denka® brand, and Lanxess with Baypren® grades. CR is classified into several grades based on Mooney viscosity and modification: general-purpose grades (Mooney viscosity 40-50), high-viscosity grades (Mooney viscosity 100-130), carboxyl-modified CR for enhanced adhesion properties, and sulfur-modified CR for improved processing characteristics.
Key Features & Benefits
- Superior Flame Retardancy: Limiting oxygen index (LOI) of 40% compared to 17-18% for conventional elastomers
- Excellent Chemical Resistance: Outstanding resistance to oils, solvents, and most industrial chemicals
- Weather Resistance: Superior ozone and UV resistance for outdoor applications
- Temperature Stability: Maintains properties from -40°C to +120°C service range
- Strong Adhesion Properties: Excellent bonding to metals, fabrics, and other substrates
- Mechanical Durability: High tensile strength and tear resistance for demanding applications
- Electrical Insulation: Good dielectric properties for wire and cable applications
- Processing Versatility: Compatible with various vulcanization systems and processing methods
- Water Resistance: Low water absorption and excellent impermeability
Applications
CR's unique combination of flame retardancy, chemical resistance, and mechanical properties makes it essential across multiple high-performance industries:
Automotive Industry
- Sealing Systems: Gaskets, O-rings, and weatherstrips with excellent fuel and oil resistance
- Hoses and Belts: Fuel lines, hydraulic hoses, and timing belts for engine applications
- Vibration Control: Engine mounts and suspension bushings utilizing CR's damping properties
- Wire Harnesses: Protective sheathing for automotive electrical systems
Construction Materials
- Roofing Membranes: Single-ply roofing systems with superior weather resistance
- Sealants and Caulks: Building envelope sealing with long-term durability
- Bridge Bearings: Structural elastomeric bearings for infrastructure applications
- Expansion Joints: Movement accommodation in concrete and steel structures
Wire and Cable Insulation
- Power Cables: Flame-retardant insulation for electrical distribution systems
- Control Cables: Industrial automation and instrumentation wiring
- Marine Cables: Shipboard electrical systems requiring water resistance
- Mining Cables: Heavy-duty applications in harsh underground environments
Industrial Adhesives
- Contact Adhesives: Footwear manufacturing and laminating applications
- Structural Bonding: Metal-to-rubber and fabric-to-rubber assemblies
- Pressure-Sensitive Adhesives: Tapes and labels for industrial applications
- Sealant Formulations: Aerospace and marine sealing compounds
Technical Specifications
CR exhibits outstanding performance characteristics with tensile strength ranging from 15-25 MPa, elongation at break of 400-800%, and excellent flame retardancy with LOI values around 40%. The material demonstrates superior chemical resistance to oils and solvents, maintains flexibility across temperature ranges from -40°C to +120°C, and offers excellent adhesion properties for bonding applications.
For full technical details and specific grade comparisons, please view our datasheet (TDS).
FAQ
What is Chloroprene Rubber used for?
Chloroprene rubber is primarily used in applications requiring flame retardancy, chemical resistance, and weather durability. Key applications include automotive gaskets and hoses, construction roofing membranes, wire and cable insulation, industrial adhesives, marine equipment, and protective clothing. Its unique combination of properties makes it ideal for safety-critical applications where conventional rubbers would fail.
Most common use—adhesives: CR (polychloroprene, neoprene) is widely used as the base polymer for contact adhesives and pressure‑sensitive adhesives thanks to its strain‑crystallization, tack, peel strength, and heat/oil resistance. Typical formulations dissolve CR with magnesium oxide/zinc oxide, antioxidants, and fillers in organic solvents. Common uses include footwear bonding, laminates, woodworking, construction, and metal‑to‑rubber/fabric assemblies.
Is Chloroprene Rubber suitable for high-temperature applications?
Yes, CR offers excellent thermal stability with continuous service temperatures up to 120°C and short-term exposure to 150°C. The material maintains its mechanical properties, chemical resistance, and flame retardancy across this temperature range, making it suitable for automotive engine compartments, industrial machinery, and electrical applications requiring elevated temperature performance.
What's the difference between Chloroprene Rubber and natural rubber?
Chloroprene rubber offers significantly superior flame retardancy (LOI 40% vs 18.5%), better chemical and oil resistance, enhanced weather resistance, and improved temperature stability compared to natural rubber. While natural rubber may have slightly better mechanical properties in some applications, CR's specialized performance characteristics make it essential for applications requiring fire safety, chemical resistance, or outdoor durability.
Contact Chloroprene Rubber Supplier Shenzhen Bohr Chem
Ready to enhance your applications with premium chloroprene rubber materials? Contact us today for technical datasheets, samples, or consultation on CR solutions including CR244, CR232 series, and specialized formulations for your specific requirements.