GB1424429A - Electrophotographic material - Google Patents

Abstract

1424429 Electro-photographic element EASTMAN KODAK CO 27 July 1973 [27 July 1972 9 March 1973] 35787/73 Heading G2C An electro-photographic element comprises an electrically conductive support, a photo-conductive composition on the support and an insulating coating on the photoconductive composition comprising a hydrophobic, cured, highly-cross-linked polymeric composition and at least ten percent by weight of a cross-linking agent therefor, the polymeric composition comprising (a) a polymer of at least one α,#-ethylenically unsaturated carboxylic acid or an alkyl half ester thereof, (b) a copolymer of at least 25 wt per cent of an α, #-ethylenically unsaturated carboxylic acid or an alkyl half ester thereof and at least one other organic compound having 3 to 20 carbon atoms and a polymerizable ethylenically unsaturated hydrocarbon portion or (c) a blend of a least 25 wt per cent of a polymer of at least one α, #-ethylenically unsaturated carboxylic acid or an alkyl half ester thereof and a polymer of at least one other organic compound having 3 to 20 carbon atoms and a polymerizable ethylenically unsaturated hydrocarbon portion. The support may be metal, paper, polyethylene, polypropylene, cellulose acetate, or polyethylene terephthalate coated with nickel and may be subbed with vinylidene chloride copolymer. The photoconductive layer comprises a triarylmethane, a binder and a thiapyrylium sensitizer. The polymer composition is exemplified by polyacrylic acid optionally with polyvinyl acetate, polymethacrylic acid, a copolymer of styrene with maleic anhydride or itaconic acid, a copolymer of acrylic acid with styrene, vinyl pyrrolidone or methylmethacrylate or a copolymer of methacrylic acid with styrene or butyl or methyl methacrylate. The cross-linking agent is preferably used in the range 20 to 80 wt per cent and may be hexamethoxy methylmelamine, an imine-terminated prepolymer, a melamine or urea-formaldehyde resin, a diglycidyl ester, a phenolic resin, phenols, glyoxal, formaldehyde or a bis(vinyl sulphonyl) ether. Many other polymer compositions and cross-linking agents are specified. The insulating coating is cured at 50 to 150‹C and may contain fillers such as clay, silica or titanium dioxide.