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US 4,394,442 AGranted
Post-stretch water-dispersible subbing composition for polyester film base
AssigneeE. I. Du Pont de Nemours and Company
InventorConrad E. Miller
Life of this patent
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Abstract
To improve adhesion of a hydrophilic photographic emulsion to a hydrophobic polyester film base the latter is energy-treated as by electrical discharge or flame treatment, and then given a sub-coating composed of an aqueous dispersion of a copolyester modified with a sulfonated aromatic compound.
Claims6
An article of manufacture comprising an energy-treated biaxially oriented polyester film base coated with
- (1) a subbing layer applied from an aqueous dispersion of a linear copolyester having a relative viscosity of from about 1.3 to about 1.7 measured as a 0.58% solution in m-cresol at 25.degree. C. which comprises the reaction product of substantially equimolar equivalents of at least two dicarboxylic acids and at least one dihydric alcohol, said dicarboxylic acid equivalents being supplied by a plurality of acid reactants which, based on a total of 100% (molar) acid equivalents, includes from about 0.1% (molar) to about 10% (molar) equivalents of an aromatic sulfonated compound having a structural formula, ##STR3## wherein:
- M is a monovalent cation selected from the group of an alkali metal, ammonium substituted ammonium, and quaternary ammonium;
- X and Y are monovalent radicals individually selected from the group having structural formulas consisting of ##STR4## wherein A is a lower alkyl group having 1-5 carbon atoms;
- m and n are positive integers of less than 20 with n being greater than 1;
- and Z is a trivalent aromatic radical;
- and wherein said copolyester is not branched, cross-linked, or used with a crosslinking agent;
- and
- (2) a gelatin-containing layer contiguous thereto.
5 more elements
Dependencies are inferred from the claim text.