Process for the production of mouldings, boards or slabs of rigid polyurethane foam

摘要

The invention relates to a process for the production of mouldings, boards or slabs of rigid polyurethane foam (for example insulating material, refrigerator insulation, building protection boards, rear spoilers) having a density of 0.01 to 0.8 g/cm<3>, by foaming the polyol component (component A) with the isocyanate component (component B) in the presence of a blowing agent (component C). The essential feature of this invention is that the blowing agent is added under high pressure in an amount of from 0.5 to 5% by weight, based on the total weight of components A, B and C, the blowing agent being added by one of the three process variants: Variant I: The blowing agent is added to component A just before atomisation. Variant II: The blowing agent is added to component B just before atomisation. Variant III: The blowing agent is added in the mixing head during atomisation.