Process for the preparation of polymers of definite viscosities

Claim 1

An improved process for preparing a copolymer and concomitantly controlling its specific viscosity to values between 0.3 and 16.8, as measured on a 1% solution in N,N-dimethylformamide at 25° C., by copolymerizing (a) a hydantoin vinyl ether of formula I ##STR2## in which R 1 represents hydrogen or an organic radical, R 2 represents an alkylene having 1 to 6 C atoms or the radical --alkylene--O) n alkylene in which the alkylenes contain 1 to 6 C atoms and n represents a number from 1 to 6, and R 3 and R 4 independently of one another each represent hydrogen, an alkyl having 1 to 6 C atoms, or an aryl or R 3 and R 4 together represent the tetramethylene or pentamethylene radical, with (b) an olefinically unsaturated polymerizable compound in a molar ratio of a:b of 1:0.01 to 1:100, in the presence of a free-radical initiator and of an inert gas at a temperature within the range of 20° C. to 110° C., wherein the improvement comprises carrying out the copolymerization reaction in a solvent mixture consisting of cyclohexane and toluene, the proportion of cyclohexane in the solvent mixture being 0.5 to 95% by volume, and where 0.1 to 30 grams of the comonomers (a) plus (b) are employed per each 100 ml of the solvent mixture.