# US 4,391,903 A · Ionic copolymers in photographic light-sensitive silver halide films

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- Number: US 4,391,903 A
- Document ID: US4391903A
- Status: Granted
- Kind: A
- Application number: 06/346,738
- Filed: 1982-02-08
- Granted: 1983-07-05
- Earliest claimed: 1982-02-08
- Assignees: E. I. Du Pont de Nemours and Company
- Inventors: Peter K. Sysak
- Web page: https://patentgrep.com/patent/US4391903A

## CPC

- G03C 1/053: Polymers obtained by reactions involving only carbon-to-carbon unsaturated bonds, e.g. vinyl polymers
- G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G)

## Abstract

Ionic copolymers of styrene sulfonic acid and maleic acid improve covering power when added to the gelatin binder employed in medical silver halide X-ray emulsions.

## Claims

### Claim 1

A photographic film comprising a silver halide emulsion layer superimposed on a support, characterized in that the binder component of the silver halide emulsion layer consists essentially of a major amount in parts by weight of gelatin and a minor amount in parts by weight of a poly(styrene sulfonic acid-co-maleic acid) salt of the formula: ##STR3## wherein M is an alkali metal, m=1-3, n=1, and x=5-50.

### Claim 2 (depends on 1)

The photographic film of claim 1 wherein the silver halide emulsion layer is a medical X-ray emulsion.

### Claim 3 (depends on 1)

The photographic film of claim 1 wherein 17-35% by weight of the gelatin in the silver halide emulsion layer has been replaced with the poly(styrene sulfonic acid-co-maleic acid) salt.

### Claim 4 (depends on 1)

The photographic film of claim 1 wherein M=sodium and m=n=1.

### Claim 5 (depends on 1)

The photographic film of claim 1 wherein M=sodium, m=3, and n=1.