Polyamine crosslinking agent formulation and its preparation

Abstract

Liquid polyamine crosslinking agent formulations based on trimerized toluylene 2,4- and/or 2,6-diisocyanate, with formation of an isocyanurate structure and hydrolysis of the isocyanate groups to amine groups, are described. The novel crosslinking agent formulations have a content of 40 to 80% of the total weight of the solids content of the crosslinking agent formulation of 1,3,5-tris-(3-amino-4-methyl-phenyl,2-methyl-3-aminophenyl) isocyanurate (I) which is not further condensed, and a content of not more than 1.0% of the total weight of the crosslinking agent formulations of toluylene-2,4- and/or -2,6-diamine (III). For the preparation, toluylene diisocyanate is trimerized, to form the isocyanurate structure, until 10 to 25% of the NCO groups have been reacted. The toluylene diisocyanate which has not undergone condensation is then distilled off, the bottom product formed by this operation is taken up directly in a solvent A and the 30 to 70% strength by weight solution formed by this procedure is metered into a hydrolysis in water/N,N-dialkyl-carboxylic acid amide in the presence of a catalytic amount of a basic catalyst. After the hydrolysis, the crosslinking agent formulations are brought to a solids content of 35 to 60% of the total weight of the formulation by distilling off a portion of the solvents and adding a solvent B.

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