Perfectionnements à l'électrophotographie

摘要

1,178,463. Electrophotographic compositions. ASHLAND OIL & REFINING CO. 22 Feb., 1967 [23 Feb., 1966], No. 8460/67. Heading C3P. [Also in Division H1] A composition for use in the production of an electrophotographic layer contains photoconductor particles dispersed in an organic and/or aqueous solution or emulsion of a binder which consists of or contains a copolymer of a main component-one or more mono-ethylenically unsaturated vinyl monomers which do not contain free hydroxyl or carboxyl groups-and two lesser components-one or more hydroxyl alkyl esters of vinyl carboxylic acids and one or moreα,#-unsaturated carboxylic acids. The main component of the copolymer may be a C 1-18 cyclic or acyclic ester of acrylic or methacrylic acid (methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl acrylate), acrylonitrile, methacrylonitrile, styrene,α-methyl styrene, o-chlorostyrene, or vinyl toluene. The ester may be a C 1-18 hydroxyalkyl acrylate or methacrylate (the acrylate and methacrylate esters of #-hydroxy ethanol, #-hydroxy propanol, #- hydroxy hexanol, #-hydroxy decanol, and 12- hydroxy stearol are mentioned). The acid component may be acrylic, methacrylic, maleic, fumaric, itaconic, citraconic, or crotonic acid, and may be present to sufficient extent in commercially available ester. The copolymer may be used alone as binder or may be used with an aminoplast (alkylated and non- alkylated condensates of aldehydes with urea, N,N1 -ethylene urea, dicyandiamide, or aminotriazines) or with a phenolic resin (phenolformaldehyde). The photo-conductor used in all examples is zinc oxide. Zinc sulphide, mercuric sulphide, and silver chloride are also mentioned. The specific examples include a dyestuff sensitizing mixture of Eosin, Sodium fluoresceinate, Alphazuine, and Alizarine Cyanine Green. Rose Bengal, Methylene Blue, Rhodamine B, dibromofluorescein and cyanine dyes are mentioned. Catalysts used in the preparation of the polymer (which is carried out in nitrogen-sparged solvents) are azo-bis-butyronitrile, di-t-butyl peroxide, and cumene hydroperoxide. Toluene-sulphonic acid or phthalic acid may be added to coating composition containing aminoplast or phenolic resins to lower the curing temperature. The electrophotographic properties of the layer produced are enhanced by the inclusion of cobalt naphthenate. A support for the photo-conductive layer may be of paper, metal, or foil.