| abstract |
A polyurethane foam which is obtained by reacting an addition-polymerizable active hydrogen component comprising a compound having a group containing active hydrogen and an addition-polymerizable functional group or comprising both this compound and a compound containing at least 2.5 groups (on the average) containing active hydrogen and not containing addition-polymerizable functional groups with an organic polyisocyanate in the presence or absence of at least one auxiliary selected from the group consisting of foaming agents and additives to polymerize the addition-polymerizable functional group and simultaneously form a polyurethane, and which has a structure in which the chains formed by the addition polymerization have been cross-linked to the polyurethane chains. The polyurethane foam is useful as a rigid polyurethane foam excellent in hardness, dimensional stability, etc. and usable as a heat insulator, shock-absorbing material, synthetic wood, etc., or is useful as a soft polyurethane foam reduced in compression set and usable as a cushioning material, shock-absorbing material, sound insulating/absorbing material, etc. |