| 摘要 |
A process for the production of fluorochlorocarbon-free, urethane-containing, soft-elastic, semirigid or rigid moldings having a cellular core and a compacted peripheral zone and an essentially pore-free, smooth surface involves reacting a) an organic and/or modified organic polyisocyanate with b) at least one relatively high-molecular-weight compound containing at least two reactive hydrogen atoms, and, if desired, c) a low-molecular-weight chain extender and/or cross-linking agent, in the presence of d) a blowing agent, e) a catalyst, f) at least one amorphous, microporous silica gel which preferably has a mean pore diameter with a frequency of occurrence of more than 40% in the range from 0.1 to 10 nm, a pore volume of from 0.15 to 1.8 ml/g and a BET surface area of from 200 to 900 m2/g, and, if desired, further additives and g) assistants, in a closed mold with compaction.
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