JPH048784B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a screen printing plate that can eliminate the harmful effects of moisture, oxygen, rubber, etc. present in the atmosphere during plate making, is easy to handle, and has high precision. A screen plate is made by applying a photoresist film to a screen, attaching a photomask to the screen, irradiating it with actinic light such as ultraviolet rays, developing it, and drying it. The photosensitive film can be formed by applying the photosensitive liquid for the screen plate directly onto the screen, or by using a photosensitive film that has been coated with the photosensitive liquid and dried on a base such as a plastic film.
It can be divided into methods of transferring a photoresist film to a screen. The former method of applying the photosensitive liquid uses a bucket squeegee and coats the photosensitive liquid 7 to 12 times to obtain the required film thickness. Therefore, it takes time to form a photoresist film per plate, and when a large plate is used, uniform coating is difficult and the film thickness accuracy is not accurate. Judging from the current state of use of screen plates, the use of the latter type of photosensitive film, which is easy to handle and provides highly accurate screen plates, is gradually increasing. As mentioned above, photosensitive film is easy to handle and is a preferred material for obtaining high-precision plates. Accidents are likely to occur. That is, the conventional photosensitive film for screen plates has a photosensitive film 11 formed on a base 10, as shown in FIG. The film 11 is adhered to the screen by means of a photosensitive liquid 13 (FIG. 4a), and then the base 10
is peeled off from the photoresist film 11 (FIG. 4b). but,
When the base 10 is peeled off from the photoresist film 11, wrinkles 14 are generated on the photoresist film 11 (FIG. 4c). This is because the water contained in the photosensitive liquid 13 has penetrated into the photosensitive film 11 and reached the base 10, as shown by arrow A in FIG.
This is because 1 is becoming difficult to dry. Therefore, in order to prevent wrinkles 14 from forming, drying must be carried out for a considerably long time. moreover,
For both, during plate making, for example, atmospheric moisture, oxygen,
Deterioration or deterioration of the image quality of the screen version due to dust etc.
Ultimately, the drawback is that it is difficult to obtain a highly accurate plate. By the way, JP-A No. 47-46102 discloses a material between a support and a thermoplastic photosensitive layer that does not become sticky when heated to a temperature of up to 150°C and that is more sensitive to the photosensitive layer than the support. Photosensitive layer transfer materials have been proposed with a thin, strongly adhering separation layer, which transfer the photosensitive layer to the substrate by thermocompression. However, when applying the above photosensitive layer transition material to the production of screen printing plates,
It has the following drawbacks: Because the photosensitive layer is bonded to the screen by thermocompression bonding, the dimensional accuracy of the screen is disrupted. Since the adhesion area between the photosensitive layer and the surface of the screen plate is small, and the photosensitive layer does not penetrate into the screen even slightly, fine images tend to peel off during printing. In order to obtain high-precision screen printing plates,
It is not preferable to use a developer other than water. For example, if a developer containing an alkaline agent is used, it tends to damage the screen plate and cause clogging. As described above, the present invention can prevent the harmful effects of moisture, oxygen, dust, etc. present in the atmosphere during plate making, and can also prevent accidents caused by wrinkles that occur when peeling off the base. It provides a method for manufacturing screen printing plates that does not cause problems with the dimensional accuracy of the screen or the adhesion between the photosensitive layer and the screen when transferred to the screen. Using a photosensitive film for screen plates, which has a protective layer and a photosensitive layer made of a photosensitive liquid for water-containing screen plates on the protective layer, when transferring the photosensitive layer to the screen, the water-containing screen is applied to the screen. The purpose is to adhere the photosensitive layer and the screen by applying a photosensitive liquid for printing plates. The method for manufacturing a screen printing plate of the present invention will be explained below with reference to the drawings. Figure 1 is a cross-sectional view of a photosensitive film used in the production of screen printing plates, in which a water-removable protective layer 2 and a photosensitive layer made of a photosensitive liquid for screen plates are sequentially formed on one base surface. It was established. FIG. 2 shows the process of using the photosensitive film of the present invention. First, a photosensitive film is pressed onto the screen printing surface of the frame 5 on which the screen 4 is stretched, with the photosensitive layer 3 facing down, and a water-containing photosensitive liquid 8 for screen printing plates is applied from the screen squeegee side of the screen 4, and the photosensitive film is exposed to light. Layer 3 and screen 4 are adhered, and after peeling off base 1, a photomask 6 is closely attached.
Next, after irradiating with actinic rays, the screen plate 7 is obtained by developing. As the base 1 used in the present invention, for example, paper,
Release paper, synthetic paper, or plastic films such as transparent, translucent, opaque, and colored films of polyester, polyethylene, polycarbonate, polyvinyl chloride, etc. can be used. The base 1 may be any material that properly adheres to the protective layer 2 and can be easily peeled off by physical force during use. Polyester film is the best in terms of dimensional stability and heat resistance. The water-removable protective layer 2 used in the present invention is preferably a material that can be removed simultaneously with the uncured photosensitive layer 3 during development, such as polyvinyl alcohol and its derivatives, polyvinylpyrrolidone,
polyethylene oxide, polyacrylamide,
Water-soluble polymers such as copolymers of methyl vinyl ether and maleic anhydride, cellulose derivatives, acrylic resins, casein, rosin, shellac, fish glue, and gum, or latexes, vinyl acetate emulsions, and other emulsions can be dispersed and removed with water. Typical examples include polymers, activators, and the like. They are alone,
Alternatively, they can be used in combination, and a leveling agent, thixotropic agent, wetting agent, etc. can be added as necessary. The coating film thickness is 0.5 to 0.5 in the dried state.
20 g/m ² , preferably in the range of 2 to 5 g/m ² . The photosensitive layer 3 used in the present invention is a photosensitive layer using a photosensitive liquid for a water-containing screen plate.
In this specification, the term "water-containing photosensitive liquid for screen plate" refers to a photosensitive liquid containing at least 1% by weight of water, preferably 10% to 70% by weight. As such a photosensitive liquid, for example, a diazo photosensitive liquid, an acrylic photosensitive liquid, and a photosensitive liquid using other photosensitive resins are preferable. The diazo photosensitive liquid is a photosensitive liquid consisting of an emulsion of vinyl acetate and polyvinyl alcohol and a diazo resin, and examples of commercially available products include Encosol and Azocol. The acrylic photosensitive liquid is a photosensitive liquid whose main component is a photopolymerizable photosensitive composition consisting of partially saponified polyvinyl alcohol, an ethylenically unsaturated compound, and a photopolymerization initiator. Examples of partially saponified polyvinyl alcohol include Gohsenol KP-08 manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.
KH-17 etc. Ethylenically unsaturated compounds include glycerin diacrylate, trimethylolpropane diacrylate, diacrylate of 3 moles of ethylene oxide adduct of trimethylolpropane, pentaerythritol triacrylate, triacrylate of 3 moles of ethylene oxide adduct of pentaerythritol, Examples include dipentaerythritol tetraacrylate. As photopolymerization initiators, benzoin or its derivatives, benzophenone or its derivatives,
Examples include derivatives such as benzyl dimethyl ketal, anthraquinone and thioxanthone, and biimidazole compounds, which may be used alone or in combination. As other photosensitive resins, photosensitive resins containing stilbazole derivatives and photosensitive resins consisting of acrylamide and water-soluble nylon can be used. In particular, in the present invention, an acrylic photosensitive liquid that is easily affected by oxygen in the air can be used. The coating film thickness is in the range of 10 to 500 g/m ² in a dry state, preferably 20 to 100 g/m ² . The photosensitive layer 3 used in the present invention may be a superposition of several types of photosensitive liquids. For example, the composition of the photosensitive liquid can be adjusted so that the edges of the resulting plate are sharp on the protective layer side, and so that the next layer sinks into the screen. Moreover, multiple coatings can be applied if necessary. As the coater used for coating, a reverse coater, a gravure coater, a doctor bleed coater, an air knife coater, an extruder, etc. are used. Usually, the protective layer is coated and dried using a reverse coater, and the photosensitive layer is coated and dried using a reverse coater if it is a single layer, or by using an extruder if it is a multilayer. In addition, water or a mixed solvent of methanol and water is used to coat the protective layer, and solvents that do not dissolve in the lower protective layer are used to coat the photosensitive layer, such as water-soluble solvents such as methyl cellosolve, ethyl cellosolve, and dioxane. It is desirable to use solvents and their mixtures with water. The coating thickness of the photosensitive layer is 20 to 40 g per coating.
Since the limit is approximately 100 g/m ² , repeat coating and drying several times to obtain a thick film of 100 g/m ² or more. The photosensitive film thus obtained is cut into appropriate lengths and stored, and the film of a desired length is taken out and used as needed. The method for producing a screen printing plate of the present invention uses a water-containing photosensitive liquid for screen printing when transferring the photosensitive layer of a photosensitive film for screen printing onto a screen. That is, the photosensitive layer of the photosensitive film is pressed against the printing surface of the screen, and, for example, a water-containing screen printing photosensitive liquid is applied to the squeegee side of the screen, and dried to remove the exposure and the water that has penetrated into the photosensitive layer. By doing this, the photosensitive layer and screen are bonded. If the above-mentioned photosensitive liquid does not completely enter the screen mesh, the image will peel off during printing, so after drying, apply additional photosensitive liquid from the squeegee surface of the screen and dry.
In some cases, the bond may be further reinforced. The above water-containing photosensitive liquid for screen printing includes:
The same photosensitive liquid for water-containing screen printing used when forming the photosensitive layer can be used. The screen plate thus obtained is exposed to light using a photolithography method, developed with water, and then dried to become a printing plate. The printing plate of the present invention obtained through such a process has printing results and printing durability preferable as a screen plate. Furthermore, the printing plate of the present invention obtained using the above-mentioned photosensitive film for screen plates always has a smooth surface and good ink permeability, making it an unprecedented screen printing plate. As explained above, since the photosensitive film for screen plate used in the manufacturing method of the present invention has a protective layer between the base and the photosensitive layer, the screen plate used when transferring the photosensitive layer to the screen The water contained in the photosensitive solution moves as follows. That is, as shown in FIG. 3, the water contained in the photosensitive solution 8 for screen plate permeates into the photosensitive layer 3 as shown by arrow B, passes through the protective layer 2, and reaches the base 1 ( Figure 3 a). Therefore, even if the base 1 is peeled off in a short period of time, the photosensitive layer 3 is not affected much (FIG. 3b). Even if the protective layer 2 is wrinkled, the protective layer 2 is removed during development, so that a screen plate having a wrinkle-free photosensitive layer 3 can be used (FIG. 3c). Example 1 A 20 wt% aqueous solution of partially saponified polyvinyl alcohol (e.g. Gohsenol GH-17; manufactured by Nippon Gohsei Kagaku Kogyo Co., Ltd.) was applied onto a base such as Lumirror 100 (polyester film manufactured by Toray Industries, Inc.) using a reverse coater. A protective layer was formed by coating and drying. Next, an acrylic photosensitive liquid (for example, an aqueous solution containing methyl cellosolve whose main components are polyvinyl alcohol, an ethylenically unsaturated compound, a photopolymerization initiator, a thermal polymerization inhibitor, etc.) is applied onto the protective layer and dried to form a photosensitive layer. I let it happen. A photosensitive film consisting of a protective layer of 5 g/m ² and a photosensitive layer of 40 g/m ² was obtained. With the base side facing down, a 300 mesh screen frame was placed on top of it, and the same photosensitive solution used to form the photosensitive layer was applied over the screen and dried to adhere the screen and photosensitive film. . The base was peeled off, the protective layer exposed on the surface was placed in close contact with the photomask, and a 4kw ultra-high pressure mercury lamp was used to irradiate it with light for 30 seconds from a distance of 1 meter. Next, the screen frame is immersed in water and developed using a spray.
A screen printing plate was obtained by drying. The surface of the screen plate was smooth, the edges of the image were sharp, and there were no speckled patterns that occur when no protective layer is used. Example 2 Photosensitive films were produced using various photosensitive liquids, and screen printing plates were obtained according to Example 1.
The table below shows a comparison between the presence and absence of a protective layer.

【table】

[Table] In the above table, Movinyl 50M and MA10
is vinyl acetate emulsion, a product of Hoechst Synthesis Co., Ltd. Gohsenol GH-17 and KP-
08 is partially saponified polyvinyl alcohol, a product of Nippon Gosei Kagaku Kogyo Co., Ltd. The diazo resin is 4-
Formaldehyde condensate of diazophenylamine. Pentaerythritol triacrylate is
Photocrosslinkable ethylenically unsaturated compound. 2-ethylanthraquinone and 5-nitroacenaphthenesulfonic acid are photopolymerization initiators. Hydroxybenzophenone sulfonic acid is a UV absorber. Stilbazole photopolymer is a 10wt% acetal of stilbazolium, which is made of γ-picoline and terephthalaldehyde, and partially saponified polyvinyl alcohol. The preferred blue dye is
It is an acidic dye. Film stability refers to storage stability after production. Transferability is judged from the state of the film surface when it is transferred to a screen. The surface condition of a screen plate refers to the surface condition of a screen plate obtained using a photosensitive film. The resolution refers to the resolution of the screen plate obtained after completing the development process shown in Example 1. Example 3 Using the polyester coated with the protective layer of Example 1, the acrylic photosensitive liquid shown in Example 2 was applied, and the stilbazole photosensitive liquid was further applied.
A photosensitive film was obtained. Example 4 Polyvinylpyrrolidone (e.g. manufactured by GAF)
PVPK-90) to form a protective layer, and the following Example 1 was followed to obtain a photosensitive film. Example 5 A photosensitive film was obtained using luminescent black paper as a base.

[Brief explanation of drawings]

FIGS. 1 to 3 show embodiments and usage steps of the photosensitive film for screen plates according to the present invention. FIG. 1 is a cross-sectional view of a photosensitive film, FIG. 2 is a cross-sectional view of the process of use, FIG. 3 is a process diagram showing how the photosensitive layer of the photosensitive film according to the present invention is transferred to a screen, and FIG. , is a process diagram showing how a photosensitive layer of a conventional photosensitive film is transferred to a screen. 1...base, 2...protective layer, 3...photosensitive layer,
4...Screen, 5...Frame, 6...Photomask, 7...Screen version.

Claims (1)

[Claims] 1. Using a photosensitive film for screen plates, in which a protective layer 2 removable with water is provided on one surface of the base, and a photosensitive layer 3 made of a water-containing photosensitive liquid for screen plates is provided thereon. When transferring the photosensitive layer 3 to the screen 4, the photosensitive layer 3 and the screen 4 are bonded by applying a photosensitive liquid 8 for a water-containing screen plate to the screen 4. Method of manufacturing screen printing plates. 2. The screen printing manufacturing method according to claim 1, wherein the base 1 is paper or plastic film.