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US 4,400,440 AGranted
Electrostatic paper base and method of making the same
AssigneeAllied Paper Incorporated
InventorMichael J. Shaw
Life of this patent
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Abstract
There is provided a method of coating a paper substrate in either sheet or web form to form a base useful in forming electrostatic masters. A thin coating of a reactive film forming resin is applied to the paper and the resin reacted with an ammonium zirconyl complex and dried. This treatment avoids blocking or sticking together of successive layers of paper coated with relatively low glass transition temperature film forming resins.
Claims16
A method for the preparation of a paper base suitable for electrostatic masters for lithographic printing comprising the steps of
- (a) applying to at least one side of a paper substrate a thin coating of a barrier coating composition which comprises
- (1) an aqueous medium,
- (2) a film-forming amount of a synthetic, organic, polymeric, thermoplastic, water-resistant, film-forming resin which is solid at ordinary temperatures, and which has a glass transition temperature less than 115.degree. C., said film forming resin also having labile hydrogen-containing groups reactive with an ammonium zirconyl complex,
- (3) less than 35% by weight (dry basis) of inorganic particulate material,
- (4) the ratio of resin to inorganic particulate material being at least 2:1;
- (b) cross-linking the resin in said coating with an ammonium zirconyl complex;
- (c) passing said paper through a dryer operating at a temperature such that the temperature of said paper substrate and coating is elevated above said resin glass transition temperature;
- and
- (d) positioning said coated paper following drying in successive layers;
- (e) said coating composition being rendered non-blocking by cross-linking with the ammonium zirconyl complex whereby fusion of the successive layers is obviated.
7 more elements
Dependencies are inferred from the claim text.