| 摘要 |
1399949 Presensitized printing plates TORAY INDUSTRIES Inc 19 March 1973 [21 March 1972] 13043/73 Heading G2C A positive-working, presensitized printing plate comprises a support, an ink-receptive photopolymerizable layer and an ink-repellent silicone rubber layer, the silicone rubber layer alone being removable by developer from the unexposed areas of the plate. The photopolymerizable layer preferably contains a binder such as a vinyl or acrylic polymers, polyalkylene oxides, polyamides, polyesters, cellulose esters and ethers, epoxy or urea, phenol- or melamine-formaldihyde resins or coumarone indene resins. The layer may also contain fillers such as silica, ferric oxide or Ca or Mg carbonate. The plate is produced by coating a support with the photopolymerizable layer and then with a silicone gum which is cured usually in air to produce the silicone rubber. The plate is image-wise exposed to polymerize the photopolymerizable la and bond the silicone rubber thereto, developed with a hydrocarbon fraction to remove only the rubber above the unexposed areas to produce a positive plate. This plate may be uniformly exposed and optionally heated to complete the bonding of the rubber layer and to polymerize the unexposed areas of the photopolymerizable layer. A protective, transparent, polymeric film may applied over the rubber layer. Reference has been directed by the Comptroller to Specification 1146618.
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