GB930988A - Improvements in and relating to electrophotographic reproduction materials - Google Patents

Abstract

A coating composition for electrophotographic plates comprises a natural or synthetic resin and a photoconductive hydrazone of the formula R1R2C=N.NR3R4, in which the R symbols represent H, alkyl, aralkyl, cycloalkyl, acyl, aryl or heterocyclic aromatic groups, of which R1 and R2 may be joined to form a ring. A sensitizing dyestuff or chlorophyll may be present, and in one example sulphosalicylic acid is added. Specified solvents are water, ethanol, glycol monomethyl ether, methyl ethyl ketone and toluene, depending on the nature of the resin of which many types are listed. The support may be metal, (e.g. aluminium), glass or a resin.ALSO:The Specification describes photoconductive resinous compositions as in Specification 853,880 but with the photoconductor there specified replaced by a hydrazone of the formula R1R2C=N.NR3R4, in which the R symbols represent H, alkyl, aralkyl, cycloalkyl, acyl, aryl or heterocyclic aromatic groups, of which R1 and R2 may be joined to form a ring. Particularly suitable are those in which R3 is acyl and R4 is H, especially the benzoyl, substituted benzoyl and pyridoyl hydrazones of aromatic and heterocyclic aldehydes. Many suitable compounds of the above formula are mentioned, alone or in admixture with one another. The sensitizing dyestuffs mentioned in Specification 853,880 may also be present, and in example sulphosalicylic acid is added.ALSO:Acyl - hydrazones of the formula R1R2C=N-NH-CO-R are prepared by heating carboxylic acid hydrazides with aldehydes, ketones or quinones in an organic solvent, e.g. ethanol; R is H, alkyl, aralkyl, aryl or a heterocyclic aromatic radical (or may be an alkylene group, giving a bis-compound), R1 is H, alkyl, or aryl, and R2 is aralkyl, aryl or a heterocyclic aromatic radical; R1 and R2 may be joined to form a ring. In examples R is H, heptadecyl, benzyl, phenyl, tolyl, hydroxyphenyl, methoxyphenyl, aminophenyl, methylaminophenyl, methylphenylamino - phenyl, dimethylaminophenyl, diethylaminophenyl, benzylaminophenyl, diphenylyl, naphthyl, hydroxynaphthyl, aminonaphthyl and pyridyl, or RCO is an adipic acid residue; R1 is H, methyl and dimethylaminophenyl; R2 is phenyl, methoxyphenyl, dimethylaminophenyl, diethylaminophenyl, dibenzyl-aminophenyl, methylenedioxyphenyl, 2 - chloro-4-dimethylaminophenyl, nitrophenyl, naphthyl, anthracyl, anthraquinonyl, styryl, fluorenyl, furyl, pyridyl, quinolyl, methylcarbazolyl and ethylcarbazolyl. R1R2CO may also be phenanthraquinone.