Copolymers of dyes and acrylamide

A structurally dyed, water insoluble, macromolecular material containing in copolymerized form, acrylamide, at least one azo, anthraquinone, pyrazolanthrone or phthalocyanine dye having at least one group of the formula:

• ##STR11## wherein R.sub.1 is hydrogen or alkyl having 1 to 4 carbon atoms, R.sub.2 is hydrogen, halogen, cyano, carboxy, carbonamido or alkoxycarbonyl with 1 to 4 carbons in the alkoxy chain, said groups being attached to a cyclic carbon atom of an aromatic nucleus of the dye molecule either directly or through an oxygen or sulfur atom or a ##STR12## R.sub.3 being hydrogen or alkyl with 1 to 4 carbon atoms, at least one colorless base monomer selected from the group consisting of:
• styrene and its substituted derivatives,
• divinylbenzene,
• polybutadiene oligomers having vinyl groups,
• acrylic, methacrylic, crotonic, chloroacrylic, maleic, and itaconic acids and their anhydrides, nitriles, esters, amides, N-monoalkyl amides and N-dialkylamides,
• ethyleneglycol diacrylate,
• methylene-bis-acrylamide and methylene-bis-methacrylamide,
• vinyl esters of saturated carboxylic acids,
• vinyl halides and vinylidene halides,
• vinylpyridines, vinylpyrrolidines, vinylquinolines, and
• N-vinyl-imidazole, N-vinyl-carbazole, N-vinyl-pyrolidones of N-vinyl-caprolactam, obtained by first copolymerizing for 30 seconds to 5 minutes, in an aqueous medium and at a temperature from 0.degree. C. to 100.degree. C., in the presence of a tetravalent cerium complex as initiator, the dye with the acrylamide to form a reactive prepolymer, and then reacting in situ said prepolymers with the base monomer and the remaining free dye and acrylamide, the amount of dye being from 0.1 to 25% by weight of the base monomer and the amount of acrylamide being from 0.5 to 50% by weight of the base monomer.