# US 8,465,904 B2 · Method for preparing a printing form from a photopolymerizable element > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,904 B2 - Document ID: US8465904B2 - Status: Granted - Kind: B2 - Application number: 12/576,370 - Filed: 2009-10-09 - Published: 2010-05-06 - Granted: 2013-06-18 - Earliest claimed: 2008-10-31 - Assignees: E. I. Du Pont de Nemours and Company - Applicants: Masayuki Kato; John R. Shock - Inventors: Masayuki Kato; John R. Shock - Web page: https://patentgrep.com/patent/US8465904B2 ## CPC - G03F 7/36: Imagewise removal not covered by groups G03F7/30 - G03F7/34, e.g. using gas streams, using plasma - 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 The invention provides a method for preparing a printing form from a photopolymerizable element. The photopolymerizable element includes a layer of a photopolymerizable composition containing an elastomeric block copolymer of polystyrene and polybutadiene having less than 15% by weight of 1,2-coupled bond segments in the polybutadiene block, an ethylenically unsaturated compound, and a photoinitiator. The method includes imagewise exposing the photopolymerizable element to actinic radiation in the presence of atmospheric oxygen; heating the element to a temperature sufficient to cause a portion of the layer to liquefy; and contacting an exterior surface of the photopolymerizable element with a development medium to allow at least a portion of the liquefied layer to be removed by the development medium. ## Claims ### Claim 1 A method for preparing a printing form from a photopolymerizable element comprising: a) providing a photopolymerizable element comprising a layer of a photopolymerizable composition comprising at least one elastomeric block copolymer having one or more non-elastomeric blocks and one or more elastomeric blocks of polybutadiene having 1,2-coupled units, an ethylenically unsaturated compound and a photoinitiator, wherein the photopolymerizable composition layer is capable of being partially liquefied, and wherein the photopolymerizable element further comprises an actinic radiation opaque layer disposed thereon forming an in-situ mask on the element; b) imagewise exposing the photopolymerizable element through the in-situ mask to actinic radiation in the presence of atmospheric oxygen; c) heating the element of b) to a temperature sufficient to cause a portion of the layer to liquefy; and d) contacting an exterior surface of the photopolymerizable element with a development medium to allow at least a portion of the liquefied layer to be removed by the development medium; wherein the 1,2-coupled butadiene units comprise less than 15% by weight of the one or more polybutadiene blocks, and the elastomeric block copolymer is at least 30% by weight, based on the total weight of the photopolymerizable composition, wherein the photopolymerizable composition further comprises a plasticizer, wherein the plasticizer is selected only from liquid polythene plasticizers having a vinyl content of not less than 60% by weight of the polydiene, and wherein the printing form resulting from the method has a textured printing surface. ### Claim 2 (depends on 1) The method of claim 1 wherein the 1,2-coupled butadiene units is 5 to 10% by weight of the one or more polybutadiene blocks. ### Claim 3 (depends on 1) The method of claim 1 wherein the elastomeric block copolymer has a molecular weight between 80,000 and 200,000. ### Claim 4 (depends on 1) The method of claim 1 wherein the elastomeric block copolymer has a styrene content of 15 to 35% by weight, based on the block copolymer. ### Claim 5 (depends on 1) The method of claim 1 wherein the elastomeric block copolymer comprises a mixture of a tri-block copolymer of polystyrene-polybutadiene-polystyrene, and a di-block copolymer of polystyrene-polybutadiene, wherein the di-block copolymer is less than 20% by weight based on the weight of the elastomeric binder. ### Claim 6 (depends on 1) The method of claim 1 wherein the elastomeric block copolymer is 30 to 80% by weight, based on the total weight of the composition. ### Claim 7 (depends on 1) The method of claim 1 wherein the photopolymerizable composition further comprises an additional block copolymer that is selected from the group consisting of a block copolymer of styrene and butadiene, and a block copolymer of styrene and isoprene. ### Claim 8 (depends on 7) The method of claim 7 wherein the additional block copolymer is from 5 to 30 weight % of the composition. ### Claim 9 (depends on 1) The method of claim 1 wherein the plasticizer is from 1 to 30% by weight of the photopolymerizable composition. ### Claim 10 (depends on 1) The method of claim 1 wherein the elastomeric block copolymer is a styrene-butadiene-styrene tri-block copolymer having less than 1% by weight of styrene-butadiene di-block based on the weight of the elastomeric block copolymer; 22 to 26% by weight of styrene based on the weight of the elastomeric block copolymer; less than 10% by weight of 1,2-coupled butadiene units based on the one or more polybutadiene blocks; and a molecular weight of about 100,000 to 150,000 g/mol. ### Claim 11 (depends on 1) The method of claim 1 wherein after step d) the photopolymerizable element has a relief surface, the method further comprising post-exposing the photopolymerizable element by overall exposing the relief surface to the actinic radiation. ### Claim 12 (depends on 1) The method of claim 1 wherein after step d) the photopolymerizable element has a relief surface, the method further comprising exposing the relief surface of the photopolymerizable element to radiation of between 200 and 300 nm. ### Claim 13 (depends on 1) The method of claim 1, wherein the elastomeric block copolymer is from 40% to 75% by weight of the photopolymerizable composition. ### Claim 14 (depends on 13) The method of claim 13, wherein the plasticizer is selected only from liquid polydiene plasticizers having a vinyl content of not less than 60% by weight of the polydiene and a molecular weight less than 5000, and the total amount of plasticizer in the photopolymerizable composition is 1 to 25% by weight, based on the total weight of the photopolymerizable composition. ### Claim 15 (depends on 1) The method of claim 1, wherein the photopolymerizable composition contains one or more of said liquid polydiene plasticizers having a vinyl content of not less than 60% by weight of the polydiene, at least one of which is liquid 1,2-polybutadiene oil having a vinyl content of not less than 85% by weight. ### Claim 16 (depends on 1) The method of claim 1. wherein the plasticizer is selected only from liquid polydiene plasticizers having a vinyl content of not less than 60% by weight of the polydiene and a molecular weight less than 5,000.