Rigid foam for prodn. of sound and heat-insulating materials

摘要

1. Rigid foam (I) is claimed, esp largely closed-cell PU or polyisocyanurate foam with a cellular structure produced by foaming rigid foam components (II), esp polyols and isocyanates, with eC02 as blowing agent and possibly using activators and/or stabilisers; the novelty is that (I) has a mainly homogeneous cell structure with cells pref below 100 microns in dia contg mainly C02 and a proportion of a physical blowing agent (III) which is practically insol in at least one of the starting materials for the foam. 2. (I) is produced as above, with below 3.5 wt% (III) homogeneously emulsified in (II) before reaction in the form of the disperse phase of an emulsion with 10-micron drop dia, and with (II) contg components for the prodn of the required amt of C02.