Process for the preparation of water-dispersible or water-soluble blocked polyisocyanates, the blocked polyisocyanates obtainable by this process and lacquer binders containing these blocked polyisocyanates as isocyanate component

A binder for coating compounds which is to be applied from the aqueous phase, which binder comprises a polyisocyanate component and a polyhydroxyl component, is free from dispersing agents and solvents and is either dispersed in water or partly dispersed and partly dissolved, characterized in that:

• (1) the polyisocyanate component consists of a water-dispersible or water-soluble blocked polyisocyanate obtainable by a process comprising reacting a polyisocyanate which is neither soluble nor dispersible in water with
• (a) a blocking agent, such that 50 to 99.8% of the isocyanate groups are blocked, and either
• (b) organic polyaminosulfonates in an amount sufficient to render the polyisocyanate dispersible or soluble, or
• (c) organic polyaminosulfonic acids and subsequently neutralizing sufficient acid groups to render the polyisocyanate dispersible or soluble;
• and
• (2) the polyhydroxyl component consists of a polyester polyol which is neither dispersible nor soluble in water and/or a polyhydroxy polyacrylate which is neither dispersible nor soluble in water;
• the above-mentioned components being present in such proportions that from 0.5 to 2 equivalents of hydroxyl groups are available per equivalent of blocked isocyanate groups.