METHOD OF MANUFACTURING PRODUCTS FROM POLYURETHANES Russian patent published in 2003 - IPC

FIELD: polymer materials. SUBSTANCE: invention relates to technology of processing cast polyurethanes, in particular to a method of manufacturing products from polyurethanes suitable for various industrial areas, which consists in interaction of oligomer based on polyethers or polyesters and bearing terminal isocyanate groups with amine- type hardener and hardening of resulting liquid polyurethane into plastic resin followed by pressing thereof into products. Hardeners constitute system consisting of, separately stored, blocked hardener with 5 to 55% of unblocked hardener containing 49-95% of the total amino groups, stoichiometric ratio of the total number of amino groups in hardeners to number of oligomer isocyanate groups being equal to 0.75-1.05. Oligomer is first mixed with hardener containing blocked amino groups and then with hardener containing unblocked ones. Hardening of liquid polyurethane is carried out at ambient temperature for 30 to 150 min, during which time Shore hardness factor of resulting plastic resin achieves 20-79 units. Method allows extending assortment and increasing reliability of rubber products owing to better quality of manufactured parts. In addition, method enables mass production of polyurethane products with time intervals between process stages, while technologic properties of plastic resin of polyurethane composition are preserved on storage during 8 h or longer. EFFECT: improved quality of products and extended their assortment. 2 tbl, 5 ex