# US 5,707,773 A · Process for preparing an aqueous developable photosensitive element

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- Number: US 5,707,773 A
- Document ID: US5707773A
- Status: Granted
- Kind: A
- Application number: 08/562,723
- Filed: 1995-11-27
- Granted: 1998-01-13
- Earliest claimed: 1993-08-27
- Assignees: E. I. Du Pont de Nemours and Company; Reichhold Chemicals, Inc.
- Inventors: Jan Grossman; John Anthony Quinn; David William Swatton; Jose Antonio Briones; Paul Thomas Shea
- Web page: https://patentgrep.com/patent/US5707773A

## CPC

- G03F 7/033: the binders being polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

An aqueous developable photosensitive element comprising a support and a photosensitive layer provided thereon, said layer containing (a) an elastomeric microgel binder having an elastomeric core which can be crosslinked and a thermoplastic noncrosslinked shell, (b) an initiator, (c) an ethylenically unsaturated monomer or oligomer and optionally (d) a basic compound capable of neutralizing the acidic functionality and method of use to make an aqueous developable flexographic printing plate is described.

## Claims

### Claim 1

A process for preparing a photosensitive element comprising:
(a) polymerizing an elastomeric monomer as a latex dispersion in water to form an elastomeric core, wherein at least 10% of the elastomeric monomer is unpolymerized;
(b) copolymerizing the unpolymerized elastomeric monomer with an ethylenically unsaturated monomer or oligomer having acidic functionality to form a core shell microgel binder;
(c) removing the water;
(d) mixing the microgel binder with (i) at least one ethylenically unsaturated monomer or oligomer, and (ii) a photoinitiator system, to form a photosensitive mixture; and
(e) applying the mixture from step (d) to a support to form a layer,
wherein step (c) can be carried out after step (b) or step (d), or simultaneously with step (d).

### Claim 2 (depends on 1)

The process of claim 1 which further comprises:
(f) adding a basic compound capable of neutralizing the acidic functionality of the shell after step (b) or step (c), or simultaneously with step (d).

### Claim 3 (depends on 2)

The process of claim 2 wherein the photosensitive mixture is formed into a sheet structure by calendering.

### Claim 4 (depends on 1)

The process of claim 1 wherein step (d) is carried out after step (b) and step (c) is carried out after step (d) wherein step (c) is accomplished by extrusion dewatering.