Double-coating positive thermosensitive CTP plate

Abstract

The invention discloses a double-coating positive thermosensitive CTP plate, and particularly relates to the application of sulfamide-formaldehyde resin in a positive thermosensitive CTP plate. The double-coating positive thermosensitive CTP plate is used for solving the technical problem that an underexposure part of a printing plate precursor is poor in alkali resistance, the hardness becomes soft, and the plate developing latitude is decreased. According to the double-coating positive thermosensitive CTP plate, a support body of a hydrophilic surface is sequentially coated with a resin layer and a thermosensitive layer; the resin layer comprises film forming resin, alkali dissolution resin, coloring background dye, a development accelerant and the like; the thermosensitive layer comprises phenolic resin, an infrared absorption agent, a dissolution inhibitor / promoter, coloring background dye and the like; the added resin in the resin layer of the positive thermosensitive CTP plate is o / p-toluenesulfonamide formuladehyde resin with the structure as shown in the specification, wherein n is 2-3, and CH3 is o / p-methylphenyl. By adopting the technical scheme, the double-coating positive thermosensitive CTP plate has good latitude and pressure.

Description

technical field [0001] The invention relates to a positive thermal CTP plate material, in particular to the application of sulfonamide formaldehyde resin in the positive thermal CTP plate material. Background technique [0002] With the development of computer image processing technology, people's attention has turned to photosensitive or thermal direct plate-making systems that directly image digital imaging information through laser beams or thermal heads. The use of large-scale semiconductor lasers or YGA lasers has the following advantages over traditional photocuring plate-making methods: high-resolution images can be obtained through short-time exposure; time-saving effects; thermal direct plate-making plates used in the system can be operated under sunlight, reaching Labor saving effect. [0003] With the continuous development of positive-working thermal lithographic printing plate precursors, patent WO / 9739894 introduces a positive-working thermal lithographic prin...

AI Technical Summary

Problems solved by technology

The printing process is realized by applying the principle of water-ink balance. The support body with hydrophilic surface provides a hydrophilic surface, which is hydrophilic and ink-repelling. The photosensitive layer is exposed and developed to form an lipophilic layer, which is lipophilic and water-repelling. It has a fountain solution dampening process. In order to reduce the surface tension of the fountain solution, a certain amount of organic solvent is added to the fountain solution. At the same time, in the cleaning of the printing machine and other operations, there is an organic solvent that touches the printing plate, which affects the printing plate. The solvent-resistant type has certain requirements. Generally, the thermoplastic phenolic resin used in the photosensitive layer has the following defects: poor wear resistance, low printing resistance when used as a lithographic plate, and poor solvent resistance, especially when using UV ink. Durability is worse, etc.

In CN1891455A, CN1292508, and JP286964, the addition of acrylamide and acrylsulfonamide to the formulation of the heat-sensitive layer of the lithographic printing plate is introduced to improve the solvent resistance of the lithographic printing plate. N-imide groups are added to the layer formula to improve the solvent resistance of the lithographic printing plate. European patents EP1506858 and EP1738900 introduce the addition of N-vinylamide polymer to the lithographic printing plate heat-sensitive layer formula to improve the lithographic printing plate. In WO9963407 and WO2004035645, a kind of amide and imide structural units are introduced on the phenolic resin to improve the solvent resistance of the lithographic printing plate. However, although the solvent resistance of the printing plate has been improved, but A new problem arises. The addition of the above-mentioned polymers causes the unexposed part of the printing plate precursor to have poor alkali resistance, soften the hardness, and reduce the development latitude of the plate.

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