Electrophotographic materials and the production thereof

A photoconductive composition comprises a halogen-containing polymeric material together with an organic photoconductive substance, and optionally other materials as given below, the polymer and photoconductor being caused to interact by heating. Specified halogen-polymers are polyvinyl halides and copolymers thereof, polyvinyl esters of chloro-acids, chlorinated and sulphochlorinated polyethylene, rubber hydrohalides, chlorinated rubber, brominated and iodinated poly-N-vinyl-carbazole, iodinated polystyrene, the reaction product of polyvinyl chloride and pyridine, and polyesters of dicarboxylic and disulphonic acids with halogen-containing dihydroxy compounds. Specified photoconductors are the compounds of Specifications 851,218, 853,880, 964,873, 964,874 and 964,876. There may also be present one of the macromolecular substances mentioned in Specification 964,873, a metal-containing polymer (e.g. the mercuri-acetate of polystyrene or polyvinyl-carbazole), a sensitiser as in Specification 964,873, a plasticizer or one of the other agents mentioned in Specification 964,873. It is preferable but not essential to remove from the halogen-polymer the stabilizers normally present therein. The photoconductor and halogen-polymer can be mixed in the presence of an organic liquid, dried and heated to 50-200 DEG C., the halogen polymer forming 1-25% of the non-volatile matter present. Polystyrene, poly-N-vinyl-carbazole and a copolymer of the latter with ethyl acrylate are iodinated by heating their solutions in nitro-benzene with iodine, iodic acid and sulphuric acid. Poly-N-vinyl-carbazole is brominated by treating with an infra-red lamp a boiling solution of the polymer in methylene chloride and bromine. A reaction product is formed by refluxing pyridine with polyvinyl chloride. According to the Provisional Specification the polymer and photoconductor can be merely mixed together without heating. Specifications 883,312 and 916,660 also are referred to. 964,878. Synthetic resin compositions; halogen containing polymer/photoconductor reaction products. GEVAERT PHOTO-PRODUCTEN N.V. May 5, 1960 [Feb. 5, 1959], No. 15633/60. Divided out of 4147/59. Headings C3P and C3R. [Also in Division H1] A photoconductive composition comprises a halogen-containing polymeric material together with an organic photoconductive substance, and optionally other materials as given below, the polymer and photoconductor being caused to interact by heating. Specified halogen-polymers are pol