Reacting epoxy resin and substituted urea or biuret with blocked isocyanate group dicarboxylic anhydride compound product
AssigneeVianova Kunstharz, A.G.
InventorWillibald Paar
Life of this patent
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Abstract
Self-crosslinking cationic paint binders based on ureide-modified epoxy resins; the preparation of these binders and their use, particularly in electrodeposition paints, is described. The modification is effected with carboxylic compounds carrying ureide groups, blocked isocyanate groups and, optionally, tertiary amino groups. The carboxylic compounds are obtained through reaction of dicarboxylic acid anhydrides or compounds carrying dicarboxylic acid anhydrides with a substituted urea or a substituted biuret. The products show excellent resistance and adhesion characteristics.
Claims9
Process for producing self-crosslinking paint binders based on amino-modified epoxy resin esters comprising reacting 5 to 100 mole-% of the epoxy groups of an epoxy resin having an epoxy equivalent weight of from 160 to 2000 with a carboxylic compound of the formula --
- HOOC -- R.sub.1 -- CO -- NR.sub.2 -- CO -- NH -- R.sub.3 -- /NCO/,
- wherein
- R.sub.1 is a saturated or unsaturated aliphatic, cycloaliphatic, or aromatic hydrocarbon radical,
- R.sub.2 is an aliphatic hydrocarbon radical,
- R.sub.3 is an aliphatic, cycloaliphatic, or aromatic hydrocarbon radical, and
- --/NCO/ is a blocked isocyanate group, or the group --NR.sub.2 --CO--NH--R.sub.3 --/NCO/ is a radical formed from a substituted urea or a substituted biuret carrying at least one blocked isocyanate, group,
- and any remaining epoxy groups with primary and/or secondary amines, the weight ratios being chosen such that the final product does not contain free epoxy groups and has an amine value of at least 30 mg KOH/g.
Dependencies are inferred from the claim text.