Process for the manufacture of soluble copolymers which contain hydroxyl groups and which copolymers can be crosslinked with organic polyisocyanates

Claim 1

A process for the manufacture of coatings from polyhydroxy compounds, which are based on copolymers, which contain hydroxyl groups and are reaction products of mixtures of styrene, methyl methacrylate, hydroxyethyl methacrylate, acrylic acid and glycidyl esters of α-alkylalkanemonocarboxylic acids and/or α,α-dialkylalkanemonocarboxylic acids, and from organic polyisocyanates in solvents which have no active hydrogen atoms, which comprises mixing A. a copolymer, which contains hydroxyl groups and consists of components (a) 26-28% by weight of styrene, (b) 20-22% by weight of methyl methacrylate, (c) 18-20% by weight of hydroxyethyl methacrylate, (d and e) 32.5-35.5% by weight of a reaction product of acrylic acid and glycidyl esters of acids selected from the group consisting of α-alkylalkanemonocarboxylic acids and α,α-dialkylalkanemonocarboxylic acids, having the empirical formula C 13 H 24 O 3 , which reaction product has the formula ##STR9## wherein R is the radical of an α-alkylalkanemonocarboxyl acid or an α,α-dialkylalkanemonocarboxylic acid and the radical has the empirical formula C 10 H 19 O 2 , and in which the incorporated components (a), (b), (c), (d) and (e) add up to 100% by weight, dissolved in solvents which do not contain active hydrogen atoms, is reacted with (B) an organic polyisocyanate, the amounts of the copolymer (A) and the polyisocyanate (B) in the mixture adding up to 100 percent by weight, and applying this mixture to a substrate to be coated, and then removing the solvent in order to obtain the finished coating.