| 摘要 |
A process for the polymerization of polyisocyanates by contact with a basic polymerization catalyst in an inert solvent to obtain isocyanurate polymers containing free isocyanate groups, is characterised in that the polymerization mixture contains not more than 0.03% by weight of water. In examples polymers are obtained from tolylene-2:4-diisocyanate and tolylene-2:6-diisocyanate in butyl acetate, ethyl acetate, methyl isobutyl ketone and a mixture of toluene and ethyl acetate, using calcium naphthenate and lead naphthenate as catalysts and with the addition of phenol to obtain mono-N-substituted carbamic esters as co-catalysts, the reaction mixtures containing less than 0.03% by weight of water. Other polyisocyanates, solvents and catalysts are mentioned. Specifications 842,154 and 920,080 are referred to.
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