Patent GB-851218-A (GB)
Title: Improvements in or relating to photographic reproduction
IPC: G03G5/06
Filed: 1957-06-03
Abstract: A composition for use on a support in electrophotography comprises a synthetic resin together with a 2:5-bis-(p-aminophenyl)-1:3:4-oxadiazole (which may be substituted in the amino groups and/or the phenyl groups), with or without a sensitising dyestuff.  Examples are given of compositions containing the following resins:-indene, coumarone, cyclohexanone condensed with methylcyclohexanone, colophony-formaldehyde, resin-modified maleic acid, phenol-modified, ketone, zinc resinate, polymerized natural resindimerized abietinic acid and chlorinated polyvinyl chloride. Other types of resins mentioned are phenolic (especially phenol-formaldehyde, which may be modified with colophony): polyvinyl chloride, acetate, acetals, alcohol and ethers; polyacrylic and methacrylic esters; poly-styrene and isobutylene; phthalates; alkyds; maleic acid resins; colophony esters of mixed higher alcohols; urea- and melamine-formaldehyde, xylene-formaldehyde; polyamides and polyurethanes; aldehyde resins; ketone resins.  Suitable oxadiazoles and sensitising dyestuffs are listed.  Solvents exemplified are benzene, toluene, methylene chloride, methanol, acetone, methyl ethyl ketone and ethyleneglycol monomethyl ether. Specifications 633,747 and 633,796 are referred to.ALSO:2 : 5-Bis-(p-aminophenyl-1 : 3 : 4-oxadiazoles, which may be substituted in the amino groups and/or the phenyl groups, are prepared by condensing p-aminobenzoic acid or substituted derivative thereof (2 mols) with a hydrazine salt (1 mol) in the presence of a dehydrating agent such as oleum or polyphosphoric acid.  The products are of the formula: <FORM:0851218/IV(b)/1> (which may be nuclearly substituted) in which R1 is H, alkyl, cycloalkyl or acyl or R2 is H or (if R1 is not cycloalkyl) alkyl.  Unsymmetrical compounds are formed if 2 mols of differently substituted p-aminobenzoic acids are used. Specified symmetrical products are those in which the aryl group is p-dimethylaminophenyl, p-diethylaminophenyl, p-amylaminophenyl, p-propylaminophenyl, p-cyclopentylaminophenyl, p - cyclohexylaminophenyl, p - dipropylaminophenyl, p - acetylaminophenyl, 4 - acetylamino - 2 - chlorophenyl, 4 - propylamino - 2 - chloro - phenyl, p-ethylaminophenyl and and p-ethylpropylaminophenyl.  The unsymmetrical products are 2 - (p - diethylaminophenyl - 5 - (p - dimethylamino-phenyl), 2-(p-propylaminophenyl)-5-(p-dimethylamino - phenyl), 2 - (p - propylamino - phenyl) - 5 - (p- - ethylaminophenyl) and 2 - (p-dimethylaminophenyl) - 5 - (4' - amino - 3' - chlorophenyl). 2 : 5-Bis-(p-acetylethylaminophenyl)-1 : 3 : 4-oxadiazole is made by acetylation of the p-ethylamino compound.  p-Cyclopentylamino-benzoic acid is made by condensing p-aminobenzoic acid with cyclo pentyl bromide. p-ethylpropylaminobenzoic acid is obtained from p-ethylamino-benzoic acid and propyl bromide.  Specifications 633,747 and 633,796 are referred to.ALSO:A composition for use on a support in electrophotography comprises a solution of a natural resin (which may be modified) together with a 2:5-bis-(p-aminophenyl)-1:3:4-oxadiazole (which may be substituted in the amino groups and/or the phenyl groups), with or without a sensitising dyestuff.  Specified resins are Manila copal, colophony esterified or modified with formaldehyde, zinc resinate, and polymerized (e.g. dimerised) or hydrated natural resins.  Suitable oxadiazoles and sensitising dyestuffs are listed.  Specifications 633,747 and 633,796 are referred to.