Isocyanate derivatives containing carbodiimide groups, a process for their production and their use as additives for aqueous solutions or dispersions of plastics

Claim 2

An isocyanate derivative which does not contain free isocyanate groups and contains (i) a content of carbodiimide groups, --N═C═N--, of about 2 to 30% by weight, (ii) on a statistical average at least about 0.8 carbodiimide groups per molecule, (iii) about 5 to 200 milliequivalents per 100 g of solids of chemically incorporated sulphonate groups and (iv) 0 to about 25%, based on solids, of chemically incorporated ethylene oxide units, --CH 2 --CH 2 --O--, in polyether chains.

Claim 3

The isocyanate derivative of claim 1 which contains (i) about 5 to 15% by weight of aromatically-bound carbodiimide groups, and (iii) about 5 to 120 milliequivalents per 100 g of solids of chemically incorporated sulfonate groups.

Claim 4

A process for producing the isocyanate derivative of claim 1 which comprises partially carbodiimidizing the isocyanate groups of an organic polyisocyanate or a mixture of organic poly- and monoisocyanates (a) having an average NCO functionality of about 1.3 to 2.5 and subsequently reacting the remaining free isocyanate groups present in the carbodiimidization product with mono- and/or polyfunctional compounds containing isocyanate-reactive groups (b) while maintaining an equivalent ratio such that there is at least one isocyanate-reactive group for every isocyanate group, characterized in that a compound containing chemically incorporated sulfonate groups or groups convertible into sulfonate groups by a neutralization reaction is used as at least a portion of component (b), any groups convertible into sulfonate groups still present on completion of the reaction being completely or partly converted into sulfonate groups by a neutralization reaction and wherein the type and quantitative ratios between the reactants used, the degree of carbodiimidization and the degree of neutralization are selected in such a way that the end products have the contents of carbodiimide and sulfonate groups defined in claim 1.

Claim 5

The process of claim 3 wherein a compound containing ethylene oxide units incorporated in a polyether chain is used as synthesis component (a) and/or (b) in a quantity such that said isocyanate derivative contains up to about 25% of said ethylene oxide units.

Claim 6

A composition which comprises the isocyanate derivative of claim 1 and an aqueous solution or dispersion of plastics containing carboxyl groups and/or groups convertible into carboxyl groups.