| 摘要 |
A process for producing moldings containing ester and urethane groups and having a cellular core and a compacted surface zone, preferably shoe soles, comprises reacting a) isocyanate semiprepolymers containing ester groups and having an isocyanate content of from 10 to 26% by weight, which in turn are prepared by reacting ai) 4,4'-MDI or mixtures of 4,4'-MDI and modified or unmodified MDI isomers, with aii) difunctional to trifunctional polyester polyols having molecular weights of from 600 to 3000 and aiii) at least one branched-chain dihydroxy compound containing at least one bonded ester unit as bridge and having a molecular weight of up to 500, with b) at least one relatively high molecular weight polyhydroxyl compound and, if desired, c) low molecular weight chain extenders and/or crosslinkers in the presence of d) blowing agents, e) catalysts and, if desired, f) additives in a closed mold with compaction. The isocyanate semiprepolymers containing ester groups which can be used in this process are liquid at room temperature.
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