JP3422047B2 - Printing plate material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing plate, and more particularly to a printing plate for laser engraving. 2. Description of the Related Art Conventionally, there has been no suitable plate material for laser engraving printing, and a sheet made by mixing carbon black with polyethylene has been proposed. Therefore, high energy was required, and practical application of low energy was extremely difficult. On the other hand, recording materials containing nitrocellulose have been proposed to increase the sensitivity, but the strength of the photosensitive layer itself and the adhesive strength with the support are weak, and the strength is insufficient as a printing plate material. Met. An object of the present invention is to provide a printing plate material which can be drawn on a surface even with a low laser energy and has high strength. The present invention is a printing plate comprising a photosensitive layer containing nitrocellulose, carbon black, and an aromatic polyester-binding resin, a polyurethane resin adhesive layer, and a PET film support. . That is, the photosensitive layer has a composition comprising nitrocellulose, carbon black, and an aromatic polyester binding resin, and the P of the support is interposed via a polyurethane resin adhesive layer.
Adhesive to ET film (biaxially stretched polyester film) to make printing plate material. Nitrocellulose has a nitrogen content of 10 to 14.
% And the degree of polymerization is various, but the nitrogen content is 11.5-1.
Those having 2.2% and a solution viscosity of 1 to 1/8 second are suitable, and two or more kinds may be blended as required. In addition to the classification based on ASTM, there are various types of carbon black, such as color, rubber, and dry battery, depending on the application. To facilitate dispersion, color chips and color pastes in which carbon black is previously dispersed in nitrocellulose are commercially available, and these can be used. Thermosetting resins, thermoplastic resins and other resins can be used as the binder resin, but a binder resin having excellent solvent resistance and abrasion resistance, particularly an aromatic polyester, is preferred. If necessary, a crosslinking agent such as a melamine resin may be added to the photosensitive layer. The adhesive layer must have good adhesiveness to both the support and the photosensitive layer and must not be affected by organic solvents or water. As a material satisfying this condition, a polyurethane resin can be used. Further, an isocyanate-based, melamine-based, or epoxy-based cross-linking agent can be used in combination to increase the strength of the adhesive layer. As a method of applying the adhesive layer, an air knife coater, a gravure coater, a wire bar coater or the like can be used. Further, during the PET film manufacturing process, the adhesive layer may be applied and formed immediately after melt extrusion and casting, or immediately after stretching in one of the directions. The coating thickness is 0.01 to 5 μm, preferably 0.1 to 5 μm.
1-2 μm applies. An antistatic treatment may be applied to the back of the PET film of the support. According to the printing plate of the present invention, the heat-decomposable photosensitive layer has a high strength and is firmly adhered to the PET film of the support. Has excellent durability. Aromatic polyester binding tree as binding resin
By using a fat, solvent resistance and abrasion resistance are excellent.
By using a polyurethane resin adhesive layer as the adhesive layer
Adhesion to both PET film and photosensitive layer
Good for printing plates without being affected by organic solvents and water
Excellent in practical use as an adhesive. (Example 1) Nitrocellulose RS1 / 4 (manufactured by Daicel Chemical Industries, Ltd.) 14.4 parts, carbon black (manufactured by Mitsubishi Kasei) 3.7 parts, polyester resin Byron 20S
S (manufactured by Toyobo) 78.1 parts, methyl ethyl ketone 10.
9 parts, isopropyl alcohol 4.3 parts, toluene 8.
Six parts were shaken for 120 minutes with a paint shaker containing steel beads having a diameter of 2 mm to obtain a photosensitive layer. On the other hand, a polyurethane resin emulsion Mercy 78 was used as an adhesive layer on a 100 μm PET film.
0 (manufactured by Toyo Polymer Co., Ltd.) is diluted with a water / isopropyl alcohol mixture to a solid content of 5%, and the solution is coated with a # 10 wire bar and dried at 110 ° C. for 2 minutes to obtain an adhesive layer of about 0.7 μm. Was. A coating solution for the photosensitive layer was applied to the adhesive layer so as to have a thickness of 20 μm and dried at 120 ° C. for 3 minutes. When the sensitivity, pit shape, solvent resistance (ethanol, chlorocene), and abrasion resistance (pencil hardness) of the obtained coating film were evaluated, good performance as a laser engraving printing plate was obtained. Further, the coating film was subjected to an adhesion test and an ethanol immersion test. As a result, the properties shown in Table 1 were obtained. (Example 2) Nitrocellulose RS1 / 4
7.7 parts (Daicel Chemical Industries, Ltd.), color paste ANP-C-903 Black (Toyo Ink) 2
4.6 parts, polyester resin Byron 20SS (manufactured by Toyobo) 43.3 parts, crosslinking agent Super Beckamine L-105
-60 (Dainippon Ink) 5.4 parts, BYK CATA
0.4 parts of LYST 450 (manufactured by BYK) and 18.7 parts of methyl ethyl meketone were dissolved and mixed to obtain a coating solution. Evaluation was made in the same manner as in Example 1 except that a polyurethane resin emulsion Mercy 730 (manufactured by Toyo Polymer) was used for the adhesive layer between the photosensitive layer and the PET film. (Example 3) Nitrocellulose RS1 / 4
6.4 parts (manufactured by Daicel Chemical Industries, Ltd.), 29.9 parts of TC Color Chip 5307 (manufactured by Taisei Kako), 97.2 parts of polyester resin Byron 30SS (manufactured by Toyobo), cross-linking agent Super Beckamine L-105-60 (Dai Nippon Ink) 13.5 parts, BYK CATALYST 450
0.9 parts (manufactured by BYK), methyl ethyl ketone
Six parts were dissolved and mixed to obtain a coating solution. Evaluation was made in the same manner as in Example 1 except that a polyurethane resin emulsion Mercy 545 (manufactured by Toyo Polymer) was used for the adhesive layer between the photosensitive layer and the PET film. Comparative Example 1 Evaluation was made in the same manner as in Example 2 except that the surface of the PET film was corona-treated to give a wetting index of 42 dyn / cm instead of applying the adhesive layer. Comparative Example 2 In Example 3, P was used as an adhesive layer.
The same evaluation was performed except that a 5% methyl ethyl ketone solution of acryloid B44 (manufactured by Rohm and Haas) was applied to the ET film surface instead of the polyurethane resin emulsion. Then, the coating films obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated for sensitivity, adhesion, ethanol immersion test, solvent resistance and abrasion resistance. [Table 1] Note 1 Evaluation of adhesiveness was performed in accordance with the base tape method of JIS K5400. 10 points: no peeling, 8 points: 5% or less of defective part, 6 points: 5 to 15% of defective part, 4 points: 15 to 35 of defective part
%, 2 points: Defective part 35-65% 0 point: Defective part 65% or more Note 2 In the ethanol immersion test, the photosensitive layer was immersed in a coating solution for 24 hours in 95% ethanol, and then the appearance and adhesion were measured. Was evaluated by the base tape method.

Claims (1)

(57) [Claims] [Claim 1] Nitrocellulose, carbon black,
And a printing plate comprising a photosensitive layer containing an aromatic polyester binding resin, a polyurethane resin adhesive layer and a PET film support.