POLYURETHANE RIGID FOAMS

摘要

The present invention relates to polyurethane rigid foams formulations. More particularly, the present invention relates to polyurethane rigid foams formulations, prepared from aromatic polyester polyols, which show improved compressive strength. The formulations include an isocyanate reacting mixture, at least one polymeric diphenylmethane diisocyanate, having a functionality of at least 2.7, and at least one blowing agent; such that the stoichiometric index of the polyisocyanate to the isocyanate reacting mixture is 1.0-1.8.

主权项

1. A polyurethane foam formulation comprising:
(A) an isocyanate reacting mixture comprising:
(i) 10-40% by weight of at least one aromatic polyester polyol having a hydroxyl number of at least 50 mg KOH/g and a functionality greater than 2;(ii) 30-75% by weight of at least one propoxylated sucrose- and/or propoxylated sorbitol-initiated polyol, having a molecular weight of 200-1,500, a hydroxyl number of at least 150 mg KOH/g and a functionality of at least 4;(iii) 5-25% by weight of at least one polyether polyol based on propylene glycol moiety, having a hydroxyl value of 50-600 mg KOH/g; all percentages in (i), (ii) and (iii) being based on the overall weight of the isocyanate reacting mixture; (B) at least one polymeric diphenylmethane diisocyanate having a functionality of at least 2.7; and (C) at least one blowing agent;such that the stoichiometric index of the polyisocyanate to the isocyanate reacting mixture is 1.0-1.8.