JPH0115863B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making a relief printing plate in which an image forming portion made of a polymeric substance is provided on a substrate.

Conventionally, as plate-making methods for letterpress printing plates made of polymeric materials, methods such as molding, methods using photosensitive resins, mechanical engraving, and laser engraving have been devised and implemented. ing. Among these methods, the molding method and the method using photosensitive resin are the most widely used plate-making methods, but it is also important to create a printing plate with an image forming area made of a seamless polymeric material (hereinafter referred to as a seamless image). is not possible.

Furthermore, although it is possible to create a seamless image using a hand engraving plate-making method, it takes time to make the plate, increases the cost, and has the disadvantage that it is difficult to express thin images. Furthermore, plate making using a mechanical engraving device requires the use of expensive equipment, and furthermore, requires a complicated control circuit to obtain a seamless image, further increasing the cost of the equipment. Furthermore, plate making using this mechanical engraving device is accompanied by the generation of burrs, so the plate materials available are extremely limited. For example, it is difficult to engrave elastic materials such as rubber.
It is not possible to make a flexo plate. Laser engraving generally uses YAG lasers and CO ₂ lasers, and it is possible to form seamless images just like mechanical engraving equipment, but the equipment is expensive and causes burrs, so it is still not practical. contains various problems.

The present invention was developed as a result of intensive studies to solve these problems, and can be widely applied to the production of letterpress printing plates using various polymeric substances including rubber, and is capable of producing sharp and fine high-molecular-weight printing plates. The present invention provides a plate-making method that makes it possible to manufacture a printing plate having an image-forming portion made of a molecular substance.

The present invention will be described in detail below with reference to an embodiment shown in the drawings.

First, as shown in FIG. 1, an arbitrary relief image 2 such as a seamless image is formed on the surface of a substrate 1 by a method such as etching, plating, engraving, or pressing. The materials used for the base 1 are iron, zinc,
There is no need to specifically limit the material as long as the relief image 2 can be formed by etching, plating, engraving, pressing, etc., including copper, nickel, etc., and its shape is not limited to sheets or cylinders.
Further, these substrates 1 may be made of rolled or pultruded metal, or may have a plating layer formed on the substrate by a method such as plating. Various methods can be considered for forming the relief image 2 on the surface of the substrate 1, including etching, plating, engraving, and press working as described above, but in consideration of cost, etching and plating are preferred.

Relief image 2 on the surface of base 1 by etching
To form an etching resist 3, as shown in FIG. 2, a photosensitive resin such as polyvinyl cinnamate or an azide rubber compound is applied to the surface of the substrate 1, and a desired image is printed and developed.
After forming, chemical etching or electrolytic etching may be performed. At this time, place a cylinder with the same circumference as the length of the image to be printed on the base 1.
A seamless relief image can be obtained on the base plate 1 by using the base plate as a base plate. The substrate 1 with the etching resist 3 thus obtained is chemically etched using an acid and an oxidizing agent, or electrolytically etched in an electrolyte. The suitability of chemical etching differs slightly depending on the type of metal forming the substrate 1, but ferric chloride solution, HNO ₃ -
Etching solutions such as H ₂ O ₂ are commonly used.

To form the relief image 2 on the surface of the substrate 1 by plating, after forming the resist image 4 on the surface of the substrate 1 in the same manner as the etching method, the relief image 2 is obtained by forming the plating layer 5 in a desired plating bath. The metal to be plated may be copper, nickel, etc., and the material is not limited in any way.
The depth of the relief image 2 varies depending on the height of the image forming portion 8 made of a polymeric substance constituting the printing plate 9 finally obtained, but considering printing suitability,
Approximately 0.2 mm to 2.0 mm is appropriate. If the depth of the relief image 2 is too shallow, ink will adhere to the non-image areas of the printing plate 9, and on the other hand, if the depth is too deep, it will take a long time for etching and plating, so it is preferably 0.2 to 1.0 mm. .

Next, relief image 2 obtained as above
In the concave portion 6 of the base 1 having
A polymer substance 7 is embedded. The polymer material 7 is made of a thermoplastic resin such as acrylic, nylon, polycarbonate, polyethylene, polypropylene, polyvinyl chloride, polyvinyl acetate, cellulose, polyester, etc., which is embedded in the recess 6 by pressing or the like using an adhesive as needed. Alternatively, it may be dissolved in a solvent and poured into the recess 6. Also, phenol, epoxy, xylene, polyester,
A thermosetting resin such as DAP may be poured into the recess 6 and cured by heating. In addition to these polymeric resins, rubber can also be used to make a flexo plate. That is, a liquid rubber for casting such as polybutadiene, polybutadiene-styrene copolymer, polybutadiene-acrylonitrile copolymer, etc. is applied to the recess 6.
Similar to the method used to make regular rubber rollers, uncross-cured rubber such as nitrile rubber, chloroprene rubber, urethane rubber, or natural rubber is sheet-pressed or wrapped around a cylindrical base and placed in a pressure vessel. A method of heating and cross-sulfurizing may also be used. Furthermore, various stabilizer additives including fillers such as carbon, CaCO ₃ and Fe ₂ O ₃ may be added to these polymeric substances as necessary.

Which polymer substance 7 is to be embedded in the recess 6 of the base 1 is appropriately selected in consideration of printability. Furthermore, these polymer substances 7 do not need to be embedded only in the recesses 6 of the substrate 1, but may be processed so as to cover the surface of the substrate 1, as shown in FIG. 4B. In this case, after coating the surface of the base 1 with the polymeric substance 7 as shown in FIG. The molecular substance 7 is polished so that the polished surfaces are at the same height. When the upper surface of the relief image 2 of the substrate 1 and the surface of the polymer material 7 are at the same height, the substrate 1 is etched using the polymer material 7 embedded in the recess 6 as an etching resist, and the polymer material 7 as shown in FIG. 5 is etched. A printing plate 9 is obtained having an image-forming portion 8 of material. The depth of etching must not exceed the height of the polymer material filled in the recess 6.

Since the present invention has the above-described configuration, a printing plate having an image forming portion made of a polymeric material according to the purpose of printing can be made precisely and inexpensively without generating burrs. Moreover, printing plates and the like having seamless images made of polymeric materials can be easily produced.

Examples of the present invention will be shown below, but the present invention is not limited to these Examples.

Example 1 The surface of a 2 mm thick zinc plate was smoothed, TPR (manufactured by Tokyo Ohka) was uniformly applied to the surface, and after drying, a positive film was attached and developed. Next, the layer of TPR remaining on the surface of the zinc plate after development was used as an etching resist, and the zinc plate was chemically etched to a depth of 0.7 mm using a HNO ₃ solution to obtain a relief image.
After etching, a 1mm thick film is coated with rubber adhesive.
Heat press the PVC board and place the PVC into the relief image recess.
Filled with resin. Next, after processing with a milling machine so that the height of the zinc plate surface and the PVC resin surface are the same, the PVC resin embedded in the relief image recess is used as an etching resist, and the depth is etched again with HNO ₃ liquid.
Chemical etching was performed to a thickness of 0.5 mm to obtain a letterpress printing plate with PVC resin as the image forming part.

Example 2 The surface of a 2 mm thick iron base was smoothed and
TPR (manufactured by Tokyo Ohka) was applied uniformly, dried, and a positive film was attached to it to form a resist image made of TPR. After development, parts of the base other than the resist image were nickel plated in an acid nickel bath to form a 0.5 mm thick relief image. After plating, Sumiraku PC-1 (manufactured by Sumitomo Durez) was poured into the relief image recesses, preheated (80°C, 1 hour), and then baked (120°C, 3 hours). Next, Sumiraku was embedded only in the concave part of the relief image.
Using PC-1 as an etching resist, chemical etching was carried out to a depth of 0.3 mm using a ferric chloride solution to obtain a relief plate having a phenolic resin as an image forming part.

Example 3 After a 1.5 mm iron plate was thinly plated with nickel in a nickel sulfate bath, copper plating was further applied to a thickness of 0.5 mm on the nickel plated layer obtained in the above step in a copper sulfate bath. After leveling the surface of the copper plating layer, TPR (manufactured by Tokyo Ohka) was applied, dried, and a positive film was attached and developed. Next, electrolytic etching was performed in an electrolyte using the TPR remaining on the substrate as an etching resist to obtain a relief image with a depth of 0.5 mm. Next, a liquid rubber having the composition shown below was poured into the relief image depressions and cured by heating at 125° C. for 30 minutes. Next, in order to remove unnecessary rubber on the relief image, it was polished with a milling machine.
The upper surface of the relief image and the upper surface of the rubber were processed so that they were at the same height. Next, the rubber embedded only in the concave portions of the relief image is used as an etching resist, and chemically etched with a ferric chloride solution to a depth of 0.3 mm. Letterpress printing has an image forming area made of 0.3 mm thick rubber. Got the edition.

(Liquid rubber composition) poly bd liquid rubber R-45 (manufactured by Idemitsu Petrochemical)
...100 parts by weight Toluene diisocyanate ...7〃 Tinnous octoate ...0.3〃 Example 4 TPR (manufactured by Tokyo Ohka) was evenly applied to the surface of a 170φ x 480mm iron cylinder, and the length was the same as the circumference of the cylinder. A positive film with a seamless image was printed and developed. A seamless image made of TPR formed on the surface of an iron cylinder was used as an etching resist, and 13% HNO ₃ , 40 and H ₂ O ₂ ,
After 30 minutes of chemical etching with a No. 10 etching solution, a relief image with a depth of 1 mm was obtained. on the relief image
After peeling off the TPR, a 0.5 mm thick nitrile rubber sheet was wrapped around this cylinder four times under pressure with a roller, and cross-cured using a pressure gadler. After cross-sulfurization, remove unnecessary rubber using a grinding wheel to expose the gold layer surface.
The rubber surface and the relief image surface were made the same surface.

Next, the nitrile rubber in the depressions of the relief image was used as an etching resist and chemically etched with the above etching solution for 20 minutes to etch the relief image by 0.6 mm to obtain a flexographic plate having a seamless image made of 0.6 mm thick nitrile rubber.

[Brief explanation of drawings]

1 to 4 are cross-sectional views of a substrate having a relief image shown to explain a part of the process of the present invention, and FIG. 5 is a cross-sectional view showing a printing plate obtained by the present invention. . DESCRIPTION OF SYMBOLS 1... Base, 2... Relief image, 3... Etching resist, 4... Resist image, 6... Recessed part, 7... Polymer substance, 8... Image forming part, 9...
...Print version.

Claims (1)

[Claims] 1. After forming a desired relief image on the surface of a substrate, embedding a polymeric substance in the recesses of the relief image, and then etching the portion of the substrate other than the resist using the polymeric substance as a resist. A plate-making method comprising producing a letterpress printing plate having an image forming portion made of a polymeric substance on the base. 2. The plate-making method according to claim 1, wherein a seamless relief image is formed on the surface of a cylindrical base.