摘要 |
The present invention relates to a process for the preparation of polyurethane foams comprising reacting polyisocyanates with dispersions of (i) polymer-containing relatively high molecular weight hydroxyl compounds that are prepared by reaction of mono- or polyisocyanates with NH-containing compounds selected from the group consisting of polyamines containing primary and/or secondary amino groups, hydrazines, hydrazides, and alkanolamines in (ii) a compound containing 1 to about 8 primary and/or secondary hydroxyl groups and having a molecular weight of about 400 to about 16,000, in the presence of water and/or organic blowing agents; catalysts; and flameproofing agents comprising an expandable graphite modified by inorganic expandable materials, alone or in combination with inorganic co-flameproofing agents.
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