Novel Polyurethane Shoe Sole Systems Having Superior Low Temperature Flex Properties

Abstract

Polyurethane microcellular shoe sole systems based on polyester polyols have traditionally exhibited superior physical properties as compared to polyether polyol based systems. Only in cold temperature flexibility have polyethers performed better than polyesters. Novel polyester polyol shoe sole systems with vastly improved cold tempera ture flex performance have been developed. These ELASTOPAN systems rely on new methylene bis(phenyl isocyanate) prepolymers that can be used to mold unit soles capable of achieving more than 60,000 flexes at —20°F. Liquidity of these sytems at room temperature greatly simplifies storing and handling of material in preparation for production. Once in production, day tanks can operate at lower temperatures and still maintain acceptable material viscosities. Production equipment (pumps, tanks, mix heads) tends to remain cleaner due to exceptional material lubricity and flowability.