Patent ID: 9562131
Date: 2017-02-07
CPC Classifications: C08G

Claim:
1. A process for producing a thermoformable rigid polyurethane-polyamide foam, comprising: mixing a) an organic polyisocyanate with b) at least one polymeric compound having two or more isocyanate-reactive hydrogen atoms, c) optionally a crosslinking agent, a chain-extending agent, or both, d) at least one carboxylic acid having a functionality of two or more, e) a catalyst comprising at least one Lewis base component selected from the group consisting of N-methylimidazole, melamine, guanidine, cyanuric acid and dicyandiamide, or a derivative of the Lewis base component, and f) optionally an auxiliary or an additive to form a reaction mixture, and reacting the reaction mixture to form the rigid polyurethane-polyamide foam, wherein the reaction mixture comprises no physical blowing agent and less than 1 wt % of water, based on the overall weight of components (a) to (f), the at least one carboxylic acid (d) is in a form selected from the group consisting of a carboxylic acid, a carboxylate salt, an acid anhydride and an ionic liquid, a closed-cell content of the rigid polyurethane-polyamide foam is less than 70%, and a density of the rigid polyurethane-polyamide foam is from 50 to 80 g/L.