| 摘要 |
The present invention is directed to a method for the production of plastics, including foams, containing urethane groups and predominantly isocyanurate groups by reacting polyesters having a molecular weight of from 350 to 10,000, and containing at least two hydroxyl groups and containing phthalic acid residues and, optionally, other polyhydroxyl compounds having a molecular weight of from 400 to 10,000 and/or chain extenders having a molecular weight of from 32 to 400 with an excess of polyisocyanates in the presence of isocyanate-trimerization catalysts and optionally blowing agents, foam stabilizers and other additives, the improvement characterized in that polyesters are used whose acid components comprise at least 50%, by weight, phthalic acid residues and wherein 10 to 49%, preferably 20 to 40%, by weight, of the isocyanate groups react to form urethane groups and 51 to 90%, preferably 60 to 80%, by weight, of the isocyanate groups react to form isocyanurate groups.
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