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US 4,379,822 AGranted
Conductive barrier coat for electrostatic masters
AssigneeAllied Paper Incorporated
InventorMichael J. Shaw
Life of this patent
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Abstract
An electrostatic master for lithographic printing characterized by a base, a barrier coat thereon, and a photo-conductive layer. The barrier coat includes a hydrophobic thermoplastic film-forming resin having labile hydrogen-containing functional groups and a conductive agent. The conductive agent is a quaternary ammonium salt. The salts have only a minimal effect on water resistance and result in excellent reduction in the dielectric characteristics of the barrier coat.
Claims8
A printing master comprising
- (a) a base;
- (b) a water resistant barrier coat applied to said base;
- (c) a photoconductive layer comprising a photoconductive material and a binder applied to said barrier coat;
- (d) said barrier coat comprising on a dry weight basis, in a film-forming amount, about 50-95% of an organic hydrophobic and thermoplastic film-forming resin having labile hydrogen-containing functional groups, and about 5-15% of a conductive agent;
- said coat having a resistivity less than about 10.sup.11 ohms per square in said barrier coat, said resin being applied to the base as either a latex or colloidal dispersion;
- (e) said conductive agent being a quaternary ammonium salt having the formula;
- ##STR4## where R.sup.1 is a radical selected from the group consisting of ##STR5## R.sup.II is lower alkyl having from one to three carbon atoms;
- A is 1, 2, or 3;
- and
- X is an anion selected from the group consisting of chloride, fluoride, bromide, sulfate, phosphate or acetate;
- said barrier coat being substantially free of materials which adversely affect water resistance.
8 more elements
Dependencies are inferred from the claim text.