CSM GP-A70
Hardness band · default condition
also Hypalon
GP-A70 = general purpose, Shore A 70
Default weather-resistant compound for hose covers, gaskets, rollers and molded goods.
Values for the GP-A70 condition
Other CSM grades and fills
CSM is listed in 10 conditions; see the grade overview at CSM.
Compare all 10 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Solution / coating & adhesive grade | Low-Mooney polymer dissolved in aromatic/chlorinated solvent for tank linings, corrosion-protective and marine paints. | — | 8 | 300 | 15 Shore D |
Roofing / pond-liner membrane sheet | Reinforced or unreinforced calendered sheet for single-ply roofing and containment liners with 20+ year weathering. | — | 9 | 300 | 21 Shore D |
Soft compound, Shore A 50 | Choose for low-closure-force seals, diaphragms and flexible sheet where softness matters more than strength. | — | 10 | 480 | 50 Shore A |
Flame-retardant compound | Specify where UL 94 V-0 or low-flame-spread jacketing/sheeting is mandated. | — | 11 | 280 | 27 Shore D |
White / light-colored weathering grade | Pick when colored, non-blooming outdoor parts are needed — CSM keeps color and gloss without carbon black. | — | 12 | 380 | 20 Shore D |
Cable jacket / electrical grade | Use for flexible cord and mining/welding cable jackets requiring heat, ozone and flame resistance. | — | 14 | 350 | 75 Shore A |
GP-A70DefaultThis page General purpose, Shore A 70 | Default weather-resistant compound for hose covers, gaskets, rollers and molded goods. | — | 16 | 320 | 22 Shore D |
High-chlorine (≈40–43% Cl) oil/chemical-resistant grade | Higher chlorine content improves oil, fuel and chemical resistance at the cost of low-temperature flexibility. | — | 17 | 300 | 72 Shore A |
Low-chlorine, low-temperature flexible grade | Choose when cold flexibility to about −45 °C matters more than oil resistance. | — | 18 | 420 | 17 Shore D |
Hard compound, Shore A 80–90 | For rolls, wear liners and extruded profiles needing higher modulus and abrasion resistance. | — | 20 | 220 | 30 Shore D |
What is CSM GP-A70?
CSM GP-A70 is CSM heat treated to GP-A70 — default weather-resistant compound for hose covers, gaskets, rollers and molded goods. CSM GP-A70 has a tensile strength of 16 MPa (2.32 ksi), weaker than 72% of polymer grades. Elongation at break is 320% and the elastic modulus is 0.01 GPa (0.001 Msi). CSM GP-A70 has a density of 1.35 g/cm³ (0.0488 lb/in³), heavier than 75% of polymer grades. Its glass-transition temperature is -25°C (-13 °F).
Advantages
- Good UV / weathering resistance — 95/100, better than 95% of polymer grades
- Ductile — tolerates forming and impact — 320%, better than 82% of polymer grades
- Forms and bends easily — 85/100, better than 81% of polymer grades
Limitations
- High mold shrinkage — 2.5%, worse than 93% of polymer grades
- Low stiffness — 0.01 GPa (0.001 Msi), worse than 84% of polymer grades
- Difficult to machine — 35/100, worse than 84% of polymer grades
- Heavy — 1.35 g/cm³ (0.0488 lb/in³), worse than 75% of polymer grades
- Absorbs moisture — dry before molding — 0.6%, worse than 75% of polymer grades
CSM GP-A70 properties
Typical room-temperature values for CSM GP-A70; 17 are specific to this condition. Other listed values are CSM reference data and may not represent this condition. Bars are the position among polymer grades.
Physical3
CSM GP-A70 has a density of 1.35 g/cm³ (0.0488 lb/in³), heavier than 75% of polymer grades. Its glass-transition temperature is -25°C (-13 °F).
Mechanical8
CSM GP-A70 has a tensile strength of 16 MPa (2.32 ksi), weaker than 72% of polymer grades. Elongation at break is 320% and the elastic modulus is 0.01 GPa (0.001 Msi).
Thermal8
CSM GP-A70 is rated for continuous service to 125°C (257 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 56% of polymer grades. Thermal expansion is 180 µm/m·K (100 µin/in·°F).
Electrical5
CSM GP-A70 is an electrical insulator with a dielectric strength of 22 kV/mm (558.8 V/mil) and a resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (85/100), better than 65% of polymer grades. UV resistance is excellent.
Sustainability3
Producing a kilogram of CSM GP-A70 takes about 105 MJ of energy and emits 4.5 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 0%.
Manufacturability6
CSM GP-A70's machinability is fair (35/100, worse than 84% of polymer grades); weldability good (65/100); formability excellent (85/100).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CSM GP-A70
Is CSM easy to machine?
Die-cutting, water-jet and cryogenic trimming preferred; conventional machining smears — use sharp blades and lubricant for skiving rolls.
Can CSM be welded?
Cured stock is not weldable; uncured or non-cured-membrane sheet is joined by solvent (toluene/xylene) or hot-air seaming and by CSM-based contact adhesives after abrasion.
Can CSM be formed, bent or molded?
Mixes on cold mill or internal mixer below ~110 °C to avoid scorch; calenders and extrudes well but is tacky — needs release/anti-tack dusting; press cure 150–180 °C with MgO acid acceptor plus sulfur-donor or peroxide cure system.
What surface finishes work on CSM?
Accepts CSM/acrylic paints and pigmenting without blooming; bonds to metal with chlorinated-rubber or phenolic primers; surface can be chlorinated/primed for adhesive lamination.
CSM 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 |
|---|---|---|
| chlorosulfonated polyethylene polymerbase polymer; chlorine 24–43 wt%, sulfur (as sulfonyl chloride) 0.8–1.5 wt% of polymer | 35 – 60 | 45 |
| chlorine (in polymer)on polymer basis, not compound | 24 – 43 | 35 |
| sulfur (sulfonyl)on polymer basis; provides cure sites | 0.8 – 1.5 | 1.1 |
| carbon black / mineral fillerN550/N774 or TiO₂+clay in light colors | 20 – 45 | 33 |
| plasticizer / process oilchlorinated paraffin, ester or aromatic plasticizer | 3 – 15 | 8 |
| MgO / litharge / epoxy acid acceptoressential HCl scavenger for heat aging | 2 – 8 | 4 |
| cure system (sulfur donor, MBTS/TMTD or peroxide cure gives best heat resistance | 1 – 5 | 3 |
| compound balance (antioxidant, wax, pigm | balance | — |
CSM GP-A70 — frequently asked
What is CSM GP-A70 used for?
CSM GP-A70 is typically used for roofing membranes, boat fenders, cable jacketing and chemical-resistant coatings. In short: ozone and weather resistant; light-colour non-blooming compounds; chemical-resistant coating base.
What is the tensile strength of CSM GP-A70?
CSM GP-A70 has a typical tensile strength of 16 MPa (2.32 ksi) — weaker than 72% of polymer grades. Strength varies by condition: see the 10 listed tempers.
Is CSM GP-A70 easy to machine?
Not especially — machinability is rated fair (35/100, worse than 84% of polymer grades). Die-cutting, water-jet and cryogenic trimming preferred; conventional machining smears — use sharp blades and lubricant for skiving rolls.
Can CSM GP-A70 be welded?
Yes — weldability is rated good (65/100). Cured stock is not weldable; uncured or non-cured-membrane sheet is joined by solvent (toluene/xylene) or hot-air seaming and by CSM-based contact adhesives after abrasion.
What surface finishes work on CSM GP-A70?
Accepts CSM/acrylic paints and pigmenting without blooming; bonds to metal with chlorinated-rubber or phenolic primers; surface can be chlorinated/primed for adhesive lamination.
Can CSM GP-A70 be formed, bent or molded?
Mixes on cold mill or internal mixer below ~110 °C to avoid scorch; calenders and extrudes well but is tacky — needs release/anti-tack dusting; press cure 150–180 °C with MgO acid acceptor plus sulfur-donor or peroxide cure system.
What is the maximum service temperature of CSM GP-A70?
CSM GP-A70 is rated for continuous use to about 125°C (257 °F), and briefly to 165°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- TOSO-CSM Chlorosulfonated Polyethylene technical bulletin — Tosoh Corporation (2022)
- Hypalon Synthetic Rubber — Properties and Compounding Guide (legacy) — DuPont Performance Elastomers (2008)
- Engineered Materials Handbook Vol. 2: Engineering Plastics / Elastomers data — ASM International (1999)
- ASTM D2000 — Classification System for Rubber Products in Automotive Applications (CE/CH type-class) — ASTM (2018)
- GB/T 5576 (CSM designation) — SAC / (1997)
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.