METHOD OF PREPARING CAST URETHANE ELASTOMERS Russian patent published in 1998 - IPC

FIELD: polymer production. SUBSTANCE: invention aims at preparing elastomers with high strength characteristics being, in particular, applicable to manufacture coatings for shafts of paper-making machines, rollers of sheet-rolling assemblies, and other large-dimension parts. Method consists in interaction of prepolymer based on polyoxymethylene glycol and 2,4-toluylenediisocyanate with 6.2-7.2% isocyanate groups and solution of 3,3'-dichloro-4,4'-diaminodiphenylmethane in two- or three-functional polyesterpolyol and prepolymer at molar ratio of the three latter (0.87-0.90):(0.10-0.13): 0.05 when two-functional polyester is involved and (0.94-0.95):(0.05-0.06): 0.05 with three- functional polyester on conversion to 1 mole of initial prepolymer. Utilization of 3,3'-dichloro-4,4'-diaminodiphenylmethane along with polyesterpolyol and prepolymer with end isocyanate groups makes it possible to obtain solution with high diamine concentration stable at room temperature. EFFECT: increased strength of elastomers. 1 tbl