NR - Natural Rubber (NR)

Clwyd reference NR
ASTM classification NR
Natural Rubber (NR) has the widest range of hardnesses, very strong and extremely resilient. Applications include those requiring strength and resistance to abrasion, sealing and shock absorption.
Typical applications


  • Components which are protected from constant air changes – i.e. inside machinery – and which do not come into contact with any oil or oil based fluids
  • Applications requiring strength and resistance to abrasion
  • Sealing and shock absorption




  • Widest range of hardnesses
  • Very strong (naturally self-reinforcing) and extremely resilient
  • Good compression set
  • Good resistance to inorganic chemicals
  • Very good deformation capacity
  • Good flex fatigue resistance
  • Very good abrasion resistance
  • Lack of resistance to oil and organic fluids
  • Relatively low maximum temperatures (75°C continuous, 100°C intermittent)
  • Poor ozone resistance, with tendency to perish in open air (can be improved to some extent by careful compounding).
Available hardness range (Shore A) 30 - 95
Upper continuous service temp. 80°C
Min. temp. for sealing applications -40°C
Minimum non-brittle  temp.  -70°C
Tensile strength (up to) 25 MPa
Elongation at break (up to) 600%
Price Bracket Very low
ASTM 1 Oil None
ASTM 2 Oil None
ASTM 3 Oil None
Kerosene None
Liquid B None
Liquid 101 None
Phosphate ester Good
Ketone None
Toluene None
Iso-octane None
Methanol Excellent
Acid (weak) Average
Acid (strong) None
Base (weak) Good
Base (strong) None
Hydrogen sulphide None
Steam None
Ozone None
Radiation Average