Loading patent…
AssigneeMitsui Chemicals, Inc.
InventorsTomoya Terauchi, Yuji Inatomi, Toshinori Matsuda, Yuko Kobayashi, Akihiro Koide
Estimating the term…
An object of the present invention is to provide a lithographic printing plate with a hydrophilic layer mainly made from resins which has a photosensitivity to the light in near infrared region, on which images can be printed directly with laser beam, requiring no development and wiping off operation, and immediately recovering from ink stains without any difficulties when an ink attaches to non-image areas on printing, and a photosensitive resin composition applied to the printing plate. A lithographic printing original plate having a photosensitive layer formed on a support is characterized in that the surface of the photosensitive layer has a phase-separation structure, and the recessed parts are formed on the surface of a photosensitive layer by the dissolution of one component of photosensitive layer constituting the phase-separation and the surface of the photosensitive layer is changed to have affinity for ink by irradiation with light
1] A lithographic printing original plate having a photosensitive layer formed on a support, wherein the surface of the photosensitive layer forms a phase-separation structure, and when the lithographic printing original plate is subjected to printing using a fountain solution, a portion derived from either one of the components that constitute the phase-separation on the surface of the printing plate after printing produces recessed parts on the surface of the photosensitive layer and the surface of the photosensitive layer has a property to be changed to have affinity for ink by irradiation with light or thermal energy.
2] A lithographic printing original plate according to claim 1, wherein the phase-separation structure is in a sea-island form, there are at least five island portions having a diameter of 0.5 μm or more to 10 μm or less in an area of 2,500 μm2 on any surface of the photosensitive layer, wherein the diameter means a short axis when the island portion has an elliptic shape with a long axis and a short axis, and at least a part of the island portions produces recessed parts on the surface of the lithographic printing original plate after printing when the plate is subjected to printing using a fountain solution.
3] A lithographic printing original plate according to claim 2, wherein the mean value of the short axes of the island portions is 0.5 μm or more to 10 μm or less.
4] A lithographic printing original plate according to claim 1, wherein the photosensitive layer contains a hydrophilic resin, and the hydrophilic resin contains a hydrophilic resin that is obtained by reacting at least a N-alkyl or N-alkylene substituted (meth)acrylamide compound represented by following general formula (1) and/or (2):
5] A lithographic printing original plate according to claim 4, wherein the hydrophilic resin is obtained by reacting further one or more kinds of compounds selected from the compounds having following general formula (3) and/or salts thereof:
6] A lithographic printing original plate according to claim 1, wherein the photosensitive layer is obtained by cross-linking a photosensitive resin composition containing a hydrophilic resin having cross-linking groups capable of reacting with at least a cross-linking agent, a cross-linking agent, and a photo thermal conversion material.
7] A lithographic printing original plate according to claim 1, wherein the photosensitive layer is obtained by cross-linking a photosensitive resin composition containing a hydrophilic resin having cross-linking groups capable of reacting with at least a cross-linking agent, a cross-linking agent, organic fine particles, and a photo thermal conversion material.
8] A lithographic printing plate that is obtained by irradiation with light or thermal energy to the lithographic printing original plate according to claim 1.
9] A photosensitive resin composition containing a hydrophilic resin obtained by reacting a N-alkyl or N-alkylene substituted (meth)acrylamide compound represented by following general formula (1), and/or (2) and a hydrophilic resin having cross-linking groups that react with at least across-linking agent, which further contains a cross-linking agent and a photo thermal conversion material.
10] A photosensitive resin composition according to claim 9, which further contains organic fine particles.