Tear strength: Polyurethane elastomers have high tear strength, especially polyester type, which is more than twice that of natural rubber. Carrying Capacity: Although the compressive strength of polyurethane elastomers is not high at low hardness, polyurethane elastomers can increase the hardness under the premise of keeping the rubber elasticity, thereby achieving a high load carrying capacity. The hardness of other rubbers is very limited, so the bearing capacity cannot be greatly improved.
Wear resistance: The abrasion resistance of polyurethane elastomers is outstanding. The test results are generally in the range of 0.03 to 0.20 mm/m, which is about 3 to 5 times that of natural rubber. In actual use, the effect is often better due to the influence of lubricants and other factors. Wear resistance is related to the tear strength and surface condition of the material. Polyurethane elastomer tear strength is much higher than other rubber, but his own friction coefficient is not low, generally 0.5 or more, which requires the actual use of attention to add oil lubricants, or add a small amount of disulfide Molybdenum or graphite, silicone oil, tetrafluoroethylene powder, etc. to reduce the friction coefficient and reduce friction heat. The coefficient of friction is also related to factors such as material hardness and surface temperature. In all cases, the coefficient of friction increases with decreasing hardness, increases with increasing surface temperature, and reaches a maximum at about 60°C.
Polyurethane catalyst water resistance: The water resistance of polyurethane elastomers at room temperature is good, no significant hydrolysis occurs in one or two years, especially polybutadiene type, polyether type and polycarbonate type. Heat and oxidation resistance: The heat resistance of polyurethane elastomers in inert gases is good, and the oxygen and ozone resistance at room temperature are also very good, especially polyester type. However, the simultaneous action of high temperature and oxygen accelerates the aging process of polyurethane. The upper limit of the temperature for continuous use of polyurethane elastomers in the air is 80-90°C, and the short-term use can reach 120°C. The temperature that significantly affects thermal oxidation is approximately 130°C. According to the variety, the polyester type has better thermal oxidation resistance than the polyether type. As the temperature decreases, the hardness, tensile strength, tear strength, and torsional rigidity of the polyurethane elastomer significantly increase, and the rebound and elongation decrease.