JPS6412375B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a material for forming images, and particularly to an image forming material capable of providing a high density, high gradation film that is applied to plate making. To date, many image-forming materials have been published that are composed of a base film, an aluminum vapor-deposited layer, a photosensitive layer, and the like. Image forming methods using these image forming materials can be broadly classified into the following two methods. One is an image forming method consisting of two steps, a development step and an erosion step, and the other method is a method in which these steps are performed simultaneously. The former is a method that uses an image forming material with a photosensitive layer formed with a photosensitive liquid such as polyvinyl cinnamate, and uses xylene (non-corrosive to aluminum) as a developer to first form an image on vapor-deposited aluminum. . Next, aluminum other than the image is dissolved and removed using an acidic or alkaline aluminum corrosive solution. As a result, the obtained image has sufficient optical properties against ultraviolet light or visible light, and since the non-image area is made of polyester (base film), the above-mentioned light rays can easily pass through. However, in the above process, various troubles occur due to the use of two types of processing agents. For example, if the residual film in the non-image area is not completely removed by the development process in the first tank, uneven corrosion will occur in the second tank, and waste liquid management will be difficult. A particularly fatal problem is that the process is too long. On the other hand, in the latter case, the above-mentioned drawbacks are eliminated because the developer and the aluminum corrosive solution are the same. However, since the aluminum is further corroded after the photosensitive layer is developed, good image resistivity is required. With well-known materials or photosensitive layers,
During corrosion, the photo-cured resist image area swells, lifting the image from the aluminum vapor-deposited layer and causing film peeling. In particular, images such as thin lines lose their effectiveness as a resist, and corrosion progresses to the aluminum deposited layer, resulting in the image disappearing in some cases. When a material with such poor adhesive strength is used, the resolution is reduced, the gamma characteristic is low, and penholes are likely to occur in a wide area solid area. In order to improve this, by processing the aluminum evaporated film, metals such as iron, copper, silver, etc., which have a smaller ionization tendency than aluminum, are present on the aluminum surface, improving the adhesive strength between the aluminum and the photosensitive layer. was. However, these treatments are not definitive and only slightly improve the adhesive strength.
It was never fully usable. moreover
Processing thin aluminum films with a thickness of 500 to 1000 Å is surprisingly difficult, and not only does the process take a long time, but it is also prone to scratches during the process, making it difficult to obtain high-quality products. Therefore,
These problems must be solved by applying a photosensitive layer immediately after vacuum deposition on the base film. In order to meet the above requirements, it was necessary to invent an image forming material that can achieve the purpose without surface treatment of the aluminum vapor deposited film. The present inventors have studied the photosensitive layer that is an element of this type of image forming material, and have discovered an image forming material having a photosensitive layer that can meet the above-mentioned purposes, leading to the present invention. That is, the present invention provides an image forming material in which an aluminum vapor-deposited layer and a photosensitive layer are sequentially provided on a base film, and in which an image can be formed by development with an alkaline aqueous solution, in which the photosensitive layer is made of a monoester of vinyltoluene and an unsaturated dibasic acid. 40 to 60 percent by weight of a copolymer with, 60 to 10 percent by weight of an ethylenically unsaturated compound having at least one methylol group in its structural formula,
An image forming material characterized by being formed from a photosensitive resin containing 1 to 20 weight percent of a photopolymerization initiator as a main component and optionally containing dyes, pigments, thermal polymerization inhibitors, chain transfer agents, etc. It is. The present invention will be explained in detail below. Copolymers include vinyltoluene (mixtures of various isomers) and monoesters of unsaturated dibasic acids; for example, monomethyl, monoethyl, monopropyl, monoisopropyl, monobutyl, maleic acid, fumaric acid or itaconic acid; Examples include monoisobutyl, monoparatertiary butyl, and copolymers with alkyl esters having 5 to 10 carbon atoms. Among the unsaturated dibasic acid monoesters, monobutyl maleate, monobutyl fumarate, and monobutyl itaconate are most preferred. The component ratio of the copolymer of the present invention is preferably 40 to 80 percent by weight of vinyltoluene and 20 to 60 percent by weight of unsaturated dibasic acid monoester. Further, as other monomers that can be added as necessary, diesters of unsaturated dibasic acids, lower alkyl (meth)acrylic acid esters, acrylonitrile, etc. can be used within a range of 0 to 20 weight percent. Examples of diesters of unsaturated dibasic acids include diethyls of maleic acid, fumaric acid and itaconic acid, such as dimethyl, methylethyl, diethyl, diisopropyl, dibutyl, diisobutyl and dioctyl. (Meth)acrylic acid lower alkyl esters include ethyl acrylate, methyl methacrylate,
Examples include ethyl methacrylate and butyl methacrylate. Among these component ratios, the most preferred is a copolymer consisting of 40 to 60 parts by weight of vinyltoluene, 20 to 50 percent by weight of a monoester of an unsaturated dibasic acid, and 0 to 20 percent by weight of a diester of an unsaturated dibasic acid. It is. The copolymer may be produced by any general polymerization method, but radical polymerization is particularly preferred. Moreover, solution polymerization is preferred as a means of polymerization. There are two methods for producing a copolymer. One method is to polymerize the above monomers together, and the other method is to make a copolymer of vinyltoluene and the above unsaturated acid anhydride and polymerize them in the same reaction solution. This is a method of esterifying with a desired alcohol using triethylamine or the like as a catalyst. The acid value of the obtained copolymer is suitably 50 to 200, preferably 100 to 150. Also, the molecular weight is 1000~
It has a number average molecular weight of 100,000, preferably 1,000 to 10,000, most preferably 3,000 to 5,000. Ethylenically unsaturated compounds include acrylates or methacrylates having at least one methylol group, such as acrylates, diacrylates, methacrylates and dimethacrylates of trimethylolpropane, or acrylates, diacrylates, triacrylates and metharylates of pentaerythritol. , dimethacrylate, trimethacrylate, or acrylate and methacrylate having at least one methylol group corresponding to the above-mentioned dipentaerythritol.
Usually, when producing these acrylates and methacrylates, various mixtures are produced,
In some cases, acrylates and methacrylates whose methylol groups are completely occupied may be produced and mixed, but as long as the main component is the desired one, there will be no problem in image formation. Furthermore, other ethylenically unsaturated compounds, epoxy acrylate, urethane acrylate, acrylamide, N,N-methylenebisacrylamide, etc. may be added, but they will not be effective. Among them, pentaerythritol triacrylate is preferred. Further, as a photopolymerization initiator, aromatic ketones such as benzophenone, diethoxybenzophenone,
Chloromethylated benzophenones, Michler's ketones, 4,4'-bis(methylamino)benzophenones, 4,4'-bis(diethylamino)benzophenones, ethylanthraquinone, 2-chlorothioxanthone and other aromatic ketones, benzoin, benzoin ethers, e.g. 2-(O-
chlorophenyl)-4.5-diphenylbiimidazole, 2-(O-chlorophenyl)-4.5-di(m-
Examples include methoxyphenyl)biimidazole. Most preferred among these is benzyl methyl ketal. The photosensitive layer constituting the present invention is made of an alkaline water-permeable resin (a copolymer of vinyltoluene and a monoester of an unsaturated dibasic acid), an ethylenically unsaturated compound,
The main component is a photopolymerization initiator. Their blending ratio is 40 to 60 weight percent copolymer, 60 to 10 weight percent ethylenically unsaturated compound, and 1 part photopolymerization initiator.
~20 weight percent is preferred. Although the copolymer used in the present invention can permeate an aqueous alkaline solution, it does not dissolve. In addition, the ethylenically unsaturated compounds are limited to compounds containing at least one methylol group in order to prevent unexposed areas of the photosensitive layer from being eluted by an alkaline aqueous solution and remaining on the aluminum surface. It is. When other ethylenically unsaturated compounds such as trimethylolpropane triacrylate are used, it takes more than three times as long to corrode the aluminum layer.
At the end of the corrosion, the photocured photosensitive layer also completely lifts off. In addition, if a water-soluble diacrylate containing four or more ethylene oxides such as polyethylene glycol diacrylate is used,
Although the image developability is good, the photocured photosensitive layer is sensitive to alkaline aqueous solutions and still tends to float. Therefore, it is essential that the ethylenically unsaturated compound serving as a constituent material of the photosensitive resin forming the photosensitive layer of the image forming material of the present invention has at least one methylol group. Coloring agents such as dyes and pigments can be added to the photosensitive layer constituting the present invention, if necessary. As dyes, basic dyes or basic oil dyes such as crystal violet, Victoria blue, malachite green, rhodamine B,
Auramine and metal salts thereof, eosin B, erythrosin, rose bengal, and others include azo dyes and anthraquinone dyes. Since many dyes tend to impair photocuring of the photosensitive layer, it is necessary to select dyes that do not reduce adhesive strength and sensitivity. In particular, one that does not absorb the absorption wavelength of the above-mentioned photopolymerization initiator is desirable. Examples of pigments include carbon black, phthalocyanine pigments, titanium oxide, dioxazine violet, and quinacridone pigments. The amount of the colorant added is based on the total amount of the photosensitive layer.
Dyes from 0.01 to 10 weight percent, pigments from 0.1 to 30
Included within weight percent ranges. Usually, the amount of colorant added to enable confirmation of photocuring of the photosensitive layer causes a decrease in adhesive strength and sensitivity as described above. Therefore, if necessary, the photocurable layer (obtained by exposing and developing the photosensitive layer) may be dyed, that is, piece-dyed, using an aqueous solution or a solvent solution of the above dye. . Piece dyeing is an effective means for checking the obtained image during the next process of reducing force. Addition of a coloring agent to the photosensitive layer is preferred for the reproducibility of details as an anti-halation effect, so both methods may be used in combination. Furthermore, it is also possible to add a thermal polymerization inhibitor if necessary. As thermal polymerization inhibitors, hydroquinone, methoquinone, phenothiazine, and as chain transfer agents, N-phenylglycine, mercaptobenzoxazole, etc. can be added. The image forming material of the present invention is obtained by sequentially providing an aluminum vapor deposited layer and a photosensitive layer on a base film, and, if necessary, providing a cover sheet and an aqueous resin layer on the photosensitive layer. Specifically, 500 to 1000 microns on a base film consisting of 50 to 150 micron polyester, etc.
It is obtained by vapor depositing and forming an aluminum layer with a thickness of Å, further dissolving the photosensitive resin described above in a solvent such as methyl cellosolve, coating using a coating machine, and drying. Of course, the image forming body of the present invention can also be used by using a commercially available aluminum vapor-deposited film (for example, "Metal Mirror" manufactured by Toray Industries, etc.) and forming a photosensitive layer on the aluminum vapor-deposited layer of this aluminum vapor-deposited film. good. The thickness of the photosensitive layer is 0.2 to 50 μm, preferably
It is preferable to apply the coating to a thickness of 0.5 μm to 1 μm, most preferably 0.7 μm. If necessary, a cover sheet or an aqueous resin layer can be provided on the photosensitive layer to prevent polymerization inhibition caused by oxygen on the surface of the photosensitive layer and to prevent blocking of other materials. The thickness of the aqueous resin layer is 0.1 to 1 μm, preferably
0.5 μm, and examples of the aqueous resin include polyvinyl alcohol and polyvinylpyrrolidone with a low degree of polymerization. Furthermore, benzophenone-O-carboxylic acid and P-nitrophenol can be added as auxiliaries. When actually making a film for plate making using the image forming material of the present invention, first, the material and the negative original are vacuum-adhered and then irradiated with a light source that emits abundant ultraviolet rays, such as a mercury lamp, an ultra-high pressure mercury lamp, or a metal halide lamp. Expose. Next, an aqueous solution of an alkaline agent capable of simultaneous development and corrosion, such as lithium hydroxide, sodium hydroxide, and an auxiliary agent,
For example, the exposed film is immersed in a solution containing sodium chloride, sodium fluoride, butyl cellosolve, or the like. Development and corrosion temperature is 30°±5
°C is preferred. Through the above steps, the desired image is formed. The present invention will be explained by examples. Example 1 (1) Production of copolymer A thermometer, a nitrogen inlet tube, a reflux condenser, and a stirrer were attached to the four-necked flask in Step 5, and the following mixture was placed in the flask. ●Vinyltoluene 590g ●Maleic anhydride 490g ●Dioxane 2160g Heat from the outside in a hot water bath and send nitrogen gas into the flask while maintaining the temperature at 60℃. When 5 g of BPO (benzoyl peroxide) is added to the reaction solution and stirring is continued, the internal temperature reaches 103°C in about 1 hour. Continue stirring and after 3 hours add 10g of trimethylamine and butyl alcohol.
Add 380g and heat to 100℃. At first, the reaction solution is cloudy, but as the reaction progresses, the solution becomes clear.
After about 3 hours, the reaction solution was poured into a large amount of water to precipitate a white polymer. By drying with hot air at 70°C for 6 hours, a nearly transparent polymer can be obtained. (This polymer is referred to as Copolymer 1.) Copolymer 1 had a yield of 150 c.ps (at 25° C.) in 20 weight percent methyl cellosolve. (2) Preparation and use of image-forming material The following photosensitive solution was coated using a whiler on a polyester film on which aluminum had been deposited to a thickness of 1000 Å, and then dried at 70° C. for 30 minutes to form a photosensitive layer. ●Above copolymer 1 5g ●Pentaerythritol triacrylate
4g ●Benzyl dimethyl ketal 0.4g ●Methoquinone 0.01g ●n-phenylglycine 0.1g ●Methyl cellosolve 100g The coating film thickness was 0.7 μm. Next, an aqueous solution of polyvinyl alcohol with a low degree of polymerization (10% by weight) was applied and dried to prepare an image forming material. After vacuum adhering the negative original to the above material,
After irradiating for 2 minutes with a 2KW ultra-high pressure mercury lamp (distance: 1m), it was immersed in a developing etchant having the following composition. The immersion is completed in 2 minutes at a liquid temperature of 30°C. ●Sodium hydroxide 10g ●Sodium chloride 1g ●Butyl cellosolve 5g ●Water 984g A positive image in which the photosensitive layer and aluminum layer were simultaneously removed was obtained in a clean state without the photocured image of the image layer rising. Example 2 (1) Production of copolymer A reaction vessel similar to that in Example 1 was set up, and the following mixture was placed in the flask. ●Vinyltoluene 600g ●Monobutyl itaconate 900g ●Dioxane 3000g Heat from the outside in a hot water bath and send nitrogen gas into the flask while maintaining the temperature at 100℃. When 6g of azobisisobutyronitrile was added to the reaction solution and stirring was continued, the internal temperature rose to 103 in about 1 hour.
It becomes ℃. Continue stirring until the viscosity is 2000±
4000g of methanol at 100c.ps (at 125℃)
and a large amount of water to obtain a white polymer (copolymer 2). Copolymer 2 has a viscosity of 20 weight percent methyl cellosolve solution of 120c.
ps (at 25℃). (2) Preparation and use of image-forming material On a polyester film on which aluminum had been deposited to a thickness of 1000 Å, the following photosensitive solution was applied using a whiler, and then dried at 70° C. for 30 minutes to form a photosensitive layer. ●Above copolymer 2 4g ●Pentaerythritol triacrylate
4g ●Benzophenone 0.2g ●4,4'-tetraethyldiaminobenzophenone 0.2g ●Phenothiazine 0.02g ●n-phenylglycine 0.1g ●Methyl cellosolve 100g The coating film thickness was 0.7 μm. Next, a polyvinyl alcohol aqueous solution with a low degree of polymerization (10% by weight) was applied and dried (0.5 μm).
The imaging material was prepared by After vacuum adhering the negative original to the above material,
After irradiating for 3 minutes with a 2KW ultra-high pressure mercury lamp (distance: 1m), it was immersed in a developing etchant having the following composition. The immersion is completed in 2 minutes at a liquid temperature of 30°C. ●Sodium hydroxide 3g ●Sodium iodine 10g ●Trisodium phosphate 5g ●Water 1 The optical density of the obtained image was 3.0 or more, and the resolution was 100 lines/mm or more. Next, in order to reduce the halftone dots in a specific part of the obtained image to the desired size, the halftone dots are reduced to approximately 50% by contacting with the following reducing liquid and leaving for 1 minute.
We were able to reduce the size by 10-15%. No pinholes were generated in the halftone dots during this process. Even after all steps were completed, the pattern strength of the image was sufficient. ●Phosphoric acid 75ml ●Sodium chloride 5g ●Bismuth oxide 1.5g ●Water 25ml Example 3 Copolymers 1 to 6 as shown below were produced under the polymerization conditions of Example 1, and under the same conditions as Example 2. A photosensitive solution was prepared, and the resulting photosensitive layer was exposed. Next, development and power reduction were performed, and the results shown below were obtained.

【table】

[Table] * After polymerization, it was monobutylated with butyl alcohol and used. ** Copolymer Example 4 for comparison 4 After copolymerization with a three-component system of vinyl toluene/itaconic anhydride/monobutyl maleate, Example 1 and Butyl esterification was performed in the same manner to prepare Copolymer 3. Next, a photosensitive solution having the composition shown below is applied using a wire bar so that the dry film thickness becomes 0.7 μm. ●Above copolymer 3 4g ●Pentaerythritol triacrylate
4g ●Benzyl dimethyl ketal 0.4g ●Methoquinone 0.01g ●Mercaptobenzoxazole 0.1g ●Oil Pink OP (Orient Chemical Co., Ltd., trade name) 0.02g ●Ethylene dichloride 5ml ●Ethyl acetate 5ml ●Methyl cellosolve 5ml ●Water 5ml Above exposure While the layer is not dry, use a wire bar to apply an aqueous resin solution with the following composition until the dry film thickness is reached.
Apply to a thickness of 0.5μm. ●Polyvinyl alcohol with a degree of polymerization of 500 and partial saponification number 5g ●Polyvinylpyrrolidone 5g ●Benzophenone-O-carboxylic acid 0.2g ●P-nitrophenol 0.01g ●Water 50ml After drying in hot air at 120°C for 3 minutes, A good image was obtained by using the same light source and performing the same processing after exposure.

Claims (1)

[Scope of Claims] 1. An image forming material comprising an aluminum vapor-deposited layer and a photosensitive layer sequentially provided on a base film and capable of forming an image by developing with an alkaline aqueous solution, wherein the photosensitive layer is made of vinyl toluene and an unsaturated dibasic acid. 40-60% by weight copolymer with monoester, 60-10% by weight ethylenically unsaturated compound having at least one methylol group in the structural formula, 1-1% photopolymerization initiator
An image forming material characterized in that it is formed from a photosensitive resin containing 20% by weight as a main component and optionally containing dyes, pigments, thermal polymerization inhibitors, chain transfer agents, etc. 2. The image forming member according to claim 1, wherein the monoester of the unsaturated dibasic acid is monoalkyl maleate, monoalkyl fumarate, monoalkyl itaconate, or a mixture thereof. 3. The image forming material according to claim 1, wherein the main component of the ethylenically unsaturated compound is pentaerythritol triacrylate.