METHOD OF MANUFACTURING MOLDED CELLULAR POLYURETHANE PRODUCTS Russian patent published in 1999 - IPC

FIELD: polymer materials. SUBSTANCE: molded cellular polyurethane products with dense surface are manufactured by interaction, in closed molds, of (i) polyisocyanate component containing 18-33.6 wt % isocyanate groups and consisting of at least one optionally modified diphenylmethane-based polyisocyanate or polyisocyanate mixture with (ii) polyol component with average hydroxyl function index 2-3 consisting of at least one polyether polyol with molecular weight 2000 to 10000 and/or at least one polyester polyol with molecular weight 2000 to 10000 and (iii) at least one bifunctional (with respect to polyaddition of isocyanate) compound with molecular weight from 62 to 1999 in amount from 2 to 15% of the weight of polyol component in presence of blowing agent and other auxiliary components known in the art. Above-mentioned blowing agent is substituted ammonium carbamate with general formula I: (I) where R¹ is hydrogen, C₁-C₅-alkyl, or residue having general formula A: (A), in which R² and R³, same or different, are hydrogen or C₁-C₃-alkyl, and n=2-6, in amounts 0.1 to 6% based on the weight of polyol component. EFFECT: improved strength and contraction characteristics of products. 4 cl, 2 ex