Process for the preparation of moulded articles having a cellular core and a densified marginal zone with modified mould-releasing properties

摘要

A process for the production of mouldings having a cellular core and a compacted peripheral zone and improved demoulding properties by the polyisocyanate polyaddition process, by reacting a) organic polyisocyanates b) relatively high-molecular-weight compounds containing at least 2 reactive hydrogen atoms, and, if desired, c) low-molecular-weight polyhydric alcohols, polyoxyalkylene-polyols and/or secondary aromatic diamines in the presence of d) an internal mould release agent, comprising A) from 0.1 to 12% by weight, based on the total weight of components (b) and (c), of a mixture of i) from 5 to 80 parts by weight of at least one organic amine, and ii) from 20 to 95 parts by weight of at least one metal salt of stearic acid, and B) from 0.01 to 32% by weight, based on the total weight of components (b) and (c), of at least one organic mono- and/or dicarboxylic acid or anhydrides thereof, e) catalysts, f) blowing agents, and, if desired, g) assistants and/or additives, in a closed mould with compaction, expediently using the low-pressure or preferably reaction injection moulding technique.