CR FR (Flame-retardant CR)
Flame-retardant grade
also Neoprene
Use for cable jackets, mass-transit and mining parts needing V-0 / high LOI with ATH-Sb2O3 loading.
Values for the FR condition
Other CR grades and fills
CR is listed in 12 conditions; see the grade overview at CR.
Compare all 12 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Closed-cell CR sponge / foam | Pick for wetsuits, thermal/acoustic insulation and low-force sealing foams; sheet or laminated with jersey. | — | 2 | 220 | 20 Shore A |
Adhesive / latex grade CR polymer | Uncured, crystallizing polymer sold for contact cements, footwear adhesives and latex dips — not a moulding compound. | — | 8 | 700 | 35 Shore A |
FRThis page Flame-retardant CR | Use for cable jackets, mass-transit and mining parts needing V-0 / high LOI with ATH-Sb2O3 loading. | — | 12 | 300 | 27 Shore D |
Very hard CR, Shore A 90 | Highly loaded compound for back-up rings, hard rollers and rigid pads; low elongation, low resilience. | — | 13 | 150 | 40 Shore D |
Soft CR, Shore A 40 | Choose for low-closure-force gaskets, flexible bellows and vibration pads needing high deflection. | — | 14 | 550 | 8 Shore D |
Hard CR, Shore A 80 | For high-pressure seals, wear pads, scraper blades and bushings where extrusion resistance matters. | — | 15 | 250 | 30 Shore D |
Low-temperature CR | For outdoor seals, boots and cold-climate weather strip where CR crystallization must be suppressed. | — | 15 | 450 | 55 Shore A |
CR, Shore A 50 | Soft-medium sealing compound for flange gaskets and weather strip with good conformability. | — | 16 | 500 | 11 Shore D |
CR, Shore A 70 | Standard O-ring / moulded seal hardness with better extrusion and abrasion resistance. | — | 16 | 300 | 22 Shore D |
A60-GPDefault General-purpose CR, Shore A 60 | Default gasket/seal/moulded-part compound; best balance of strength, elasticity and weather resistance. | — | 17 | 400 | 15 Shore D |
W-type (mercaptan-modified, non-sulfur-modified) polymer base | Pick for best heat aging, low compression set and storage stability — moulded seals, hose, O-rings. | — | 19 | 450 | 15 Shore D |
G-type (sulfur-modified) polymer base | Choose when tear strength, building tack and dynamic flex life dominate — belt covers, footwear, mounts. | — | 21 | 500 | 14 Shore D |
What is CR FR?
CR FR is CR in the FR grade — use for cable jackets, mass-transit and mining parts needing V-0 / high LOI with ATH-Sb2O3 loading. CR FR has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 300% and the elastic modulus is 0.01 GPa (0.0012 Msi). CR FR has a density of 1.55 g/cm³ (0.056 lb/in³), heavier than 91% of polymer grades. Its glass-transition temperature is -45°C (-49 °F). A60-GP is the default condition FabDigit quotes; FR is available on request or by drawing note.
Advantages
- Good UV / weathering resistance — 85/100, better than 88% of polymer grades
- Ductile — tolerates forming and impact — 300%, better than 81% of polymer grades
Limitations
- Difficult to machine — 25/100, worse than 93% of polymer grades
- Heavy — 1.55 g/cm³ (0.056 lb/in³), worse than 91% of polymer grades
- Absorbs moisture — dry before molding — 1%, worse than 84% of polymer grades
- Low stiffness — 0.01 GPa (0.0012 Msi), worse than 82% of polymer grades
- High mold shrinkage — 2%, worse than 81% of polymer grades
CR FR properties
Typical room-temperature values for CR FR; 19 are specific to this condition. Other listed values are CR reference data and may not represent this condition. Bars are the position among polymer grades.
Physical4
CR FR has a density of 1.55 g/cm³ (0.056 lb/in³), heavier than 91% of polymer grades. Its glass-transition temperature is -45°C (-49 °F).
Mechanical8
CR FR has a tensile strength of 12 MPa (1.74 ksi), weaker than 76% of polymer grades. Elongation at break is 300% and the elastic modulus is 0.01 GPa (0.0012 Msi).
Thermal8
CR FR is rated for continuous service to 100°C (212 °F). It conducts heat at 0.24 W/m·K (0.139 BTU/hr·ft·°F), better than 67% of polymer grades. Thermal expansion is 200 µm/m·K (111.1 µin/in·°F).
Electrical5
CR FR is an electrical insulator with a dielectric strength of 14 kV/mm (355.6 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), worse than 52% of polymer grades. UV resistance is excellent.
Sustainability4
Producing a kilogram of CR FR takes about 105 MJ of energy and emits 4.2 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 5%.
Manufacturability5
CR FR's machinability is poor (25/100, worse than 93% of polymer grades); formability good (60/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CR FR
Is CR easy to machine?
Cut by steel-rule die, waterjet or knife/CNC oscillating blade; drilling and turning need sharp tools, freezing or grinding wheels because the rubber tears and heats up.
Can CR be welded?
Not thermally weldable once vulcanized — join by CR contact cement, hot vulcanized splicing, or overmoulding onto an uncured layer.
Can CR be formed, bent or molded?
Mill/internal-mixer compounding then compression, transfer or injection moulding, extrusion or calendering; press cure typically 150–180 °C with metal-oxide/thiourea systems, post-cure for low compression set.
What surface finishes work on CR?
Surfaces can be talc-dusted, chlorinated or primer-treated for bonding and painting; molded flash removed by cryogenic deflashing, and adhesion to metal achieved with phenolic/CR bonding agents.
CR chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| polychloroprene (2-chloro-1,3-butadiene polymer contains ~40 wt% chlorine; ASTM D1418 designation CR | 40 – 65 | 55 |
| carbon black (N550/N774 type)reinforcing filler; replaced by clay/silica/CaCO3 in light-coloured grades | 10 – 40 | 25 |
| plasticizer / process oil (naphthenic, eesters used for low-temperature grades | 3 – 20 | 10 |
| ZnOcure activator / HCl acceptor | 3 – 6 | 5 |
| MgOacid acceptor, scorch control | 2 – 5 | 4 |
| accelerators, antioxidant, stearic acid,ETU/thiourea or thiuram systems; sulfur only for W-type | 1 – 4 | 2 |
CR FR — frequently asked
What is CR FR used for?
CR FR is typically used for wetsuits, gaskets, hoses, cable jacketing and adhesives. In short: balanced weather and oil resistance; flame-resistant general elastomer; standard wetsuit foam.
What is the tensile strength of CR FR?
CR FR has a typical tensile strength of 12 MPa (1.74 ksi) — weaker than 76% of polymer grades. Strength varies by condition: see the 12 listed tempers.
Is CR FR easy to machine?
Not especially — machinability is rated poor (25/100, worse than 93% of polymer grades). Cut by steel-rule die, waterjet or knife/CNC oscillating blade; drilling and turning need sharp tools, freezing or grinding wheels because the rubber tears and heats up.
Can CR FR be welded?
Not thermally weldable once vulcanized — join by CR contact cement, hot vulcanized splicing, or overmoulding onto an uncured layer.
What surface finishes work on CR FR?
Surfaces can be talc-dusted, chlorinated or primer-treated for bonding and painting; molded flash removed by cryogenic deflashing, and adhesion to metal achieved with phenolic/CR bonding agents.
Can CR FR be formed, bent or molded?
Mill/internal-mixer compounding then compression, transfer or injection moulding, extrusion or calendering; press cure typically 150–180 °C with metal-oxide/thiourea systems, post-cure for low compression set.
What is the maximum service temperature of CR FR?
CR FR is rated for continuous use to about 100°C (212 °F), and briefly to 125°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM D1418 – Rubber nomenclature (CR) — ASTM (2022)
- ASTM D2000 – Classification system for rubber products in automotive applications (BC/BE types) — ASTM (2021)
- ISO 1629 – Rubber and latices, nomenclature — ISO (2013)
- Denka Chloroprene M/A/S series technical data — Denka Company Ltd. (2023)
- Neoprene (polychloroprene) product and compounding guides — Arlanxeo / former DuPont Performance Elastomers (2020)
- Engineered Materials Handbook Vol. 2 – Engineering Plastics & Elastomers — ASM International (1988)
- Rubber Technology (Morton), chloroprene chapter — Springer (1999)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.