JPS641010B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention forms a highly concentrated colored image using a water-soluble dye and a highly concentrated pigment image that firmly adheres to a plastic sheet-like substrate and does not stain the non-image area. This relates to photosensitive sheets that can be produced.

Currently, as a common method for obtaining particularly high-density images, such as when creating second original drawings for maps, blueprints, etc., polyvinyl alcohol, gelatin, casein, egg white, and glue are used on the matte side of plastic sheets. A photosensitive solution containing a water-soluble polymer such as the binder and dichromate as the photosensitive agent is applied, a negative film is adhered, and UV exposure is performed, and the non-image areas are eluted with water to create a pattern image. After forming, a method of dyeing with a water-soluble dye is used. The dichromate photosensitizer used in this case has the advantage of being able to be developed with water, producing strong image areas, and providing images with high resolution. However, on the other hand,
This photosensitizer has the disadvantage that a so-called dark reaction occurs under storage conditions of normal temperature and normal humidity, and unexposed areas also become insoluble in water, making them unusable. Therefore, photosensitive sheets coated with dichromate photosensitizers have a short lifespan and are therefore difficult to commercialize.

Furthermore, since the use of dichromate-based photosensitizers is regulated due to chromium pollution problems, diazo resins are currently mainly used as water-soluble photosensitizers. This diazo-based photosensitive resin was produced in
-29523 and Japanese Patent Publication No. 46-27482, it becomes water-soluble by photocrosslinking with water-soluble polymers such as polyvinylpyrrolidone, polyacrylamide, and polyvinyl alcohol, but compared to dichromate photosensitizers, The drawback is that the image intensity after photo-crosslinking is weak. In particular, when a certain degree of image density is required, such as when creating a second original, the photosensitive layer must be made thicker in order to obtain the desired image density, which further weakens the image intensity.

Furthermore, these diazo photosensitizers have the disadvantage that when applied to the matte surface of a plastic sheet, the diazo resin is adsorbed to the matte surface and cannot be removed during development, thereby staining the background of non-image areas. In particular, when pigments are mixed into diazo photosensitizers,
Pigment adsorption also reduces image contrast. To solve the above problem, Japanese Patent Publication No. 54-5686 uses a water-soluble polymer material as an undercoat layer on the film to eliminate stains on the background, but in this case, the water-soluble polymer material Because it is easily soluble in water, the image strength is low, and the phenomenon that the image area is easily washed out during development has often been observed.

That is, the use of dichromate photosensitizers is still good, but photosensitive sheets using diazo photosensitizers suffer from severe swelling during development and have the disadvantage of narrowing the development latitude. Similar to dichromate photosensitizers, when using diazo resin, the water-soluble polymer used for the undercoat layer diffuses into the photosensitive layer, but diazo resin in particular is adsorbed to the matte surface of the plastic sheet and becomes non-functional. In order to prevent this adsorption, the thickness of the undercoat layer must be about 1 to 2 microns, since it will stain the background of the image area. For this reason, there is a method of forming an image by coating a photosensitive agent made of polyvinyl alcohol mixed with diazo resin on an undercoat layer coated with polyvinyl alcohol to a thickness of 2μ, but this method also has a narrow development latitude. I have no choice but to do so. This is because the polyvinyl alcohol in the lower layer may be dissolved at the same time as the diazo photosensitive agent in the upper layer is developed.

The inventors of the present invention have conducted intensive research to create a photosensitive sheet for forming colored images that has no stains on the matte surface of the plastic sheet, has high image contrast, has a wide development latitude, and has good storage stability. On the matte surface of the base,
By providing a subbing layer of a water-swellable polymer film and on top of that layer a diazo-based photosensitive coating that is less swollen in water than the subbing layer, the above objective can be achieved. It has been found that it is possible to obtain a photosensitive sheet for forming colored images that has strong adhesion and does not cause staining of the background due to adsorption of pigments.

The plastic sheet-like substrate used in the present invention includes waterproof synthetic paper, polyolefin,
Polycarbonate, polyester, nylon, etc. are used, and depending on the purpose, matte processing is often used by forming a rough surface on one side by a known method such as sandblasting.

The water-swellable polymer film used as the subbing agent of the present invention is a polymer film that does not completely dissolve in water and can be removed by rubbing when wet with water. Diffusion contamination is much less. In particular, the water-swellable polymer film that improves the strength of the photosensitive film preferably contains a hydrophilic polymer having alcoholic hydroxyl groups in the molecule that are easily photocrosslinked with the diazo resin. Particularly preferable water-swellable polymers to be used as subbing agents include vinyl acetate homopolymer emulsion (aqueous solution), acrylic ester copolymer emulsion (aqueous solution), maleate ester copolymer emulsion (aqueous solution), and polyvinyl alcohol and polyester copolymer emulsion (aqueous solution). Mixed emulsion of vinyl acetate (aqueous solution), mixed emulsion of polyvinyl alcohol and polyacrylic acid ester (aqueous solution), copolymer of polyvinyl acetate and methacrylic acid with saponification degree of 40% (water + methanol liquid) and polyvinyl acetate Mixed emulsion (aqueous solution) with emulsion, copolymer of hydroxyethyl acrylate and methyl methacrylate (90:10), etc.

The film formed from these water-swellable polymers is
Compared to water-soluble polymer films such as polyvinyl alcohol, its solubility in water is lower, so if the diazo photosensitive layer is developed with an alkaline agent other than water or an aqueous solution containing a surfactant, the adhesion between the photosensitive layer and the sheet substrate will be improved. It is possible to remove it without making it worse. Since this water-swellable polymer membrane has less diffusion and contamination of the diazo resin and pigment, the thinner the membrane thickness, the better, and preferably about 1 to 2 microns.

The diazo-based photosensitive coating used in the present invention preferably has a photosensitive layer that swells in water as easily as or more easily than the undercoat layer. diazo photosensitizer,
Or a diazo system whose main components are a water-insoluble polymer having an alcoholic hydroxyl group and a water-insoluble diazo photosensitizer as described in Japanese Patent Publication No. 47-1167, Japanese Patent Publication No. 51-6566, and Japanese Patent Publication No. 53-3216. Photosensitive compositions such as 2-hydroxypropyl methacrylate, methyl methacrylate, acrylonitrile-
A solvent-soluble diazo-based photosensitizer made of a methacrylic acid copolymer and a solvent-soluble diazo-based photosensitizer is used. Diazo-based emulsions are washed out with water, but solvent-soluble diazo-based photosensitizers are developed and washed out with an aqueous solution containing an alkaline agent or a surfactant. In the diazo-based photosensitive coating used in the present invention, the photocrosslinked image area is highly water resistant and has good dyeability with water-soluble dyes.

The diazo resin used in the present invention is, for example, 4-
Condensates of diazodiphenylamine salt and formalin, condensates of 4-diazo-3-methoxydiphenylamine salts and formalin, condensates of 2,5-dimethoxy-4-mophorinobenzenediazonium and formalin, etc. is preferable, and for the solvent-soluble diazo photosensitizer, the above-mentioned diazo resin is combined with p-toluenesulfonic acid, dodecylbenzenesulfonic acid,
-Hydroxy-4-methoxybenzophenone-5
- Those coupled with organic sulfonic acids such as sulfonic acids are used.

The photosensitive layer of the present invention is post-dyed with a water-soluble dye after development to create a colored image, and the photosensitive layer is kneaded with pigments such as carbon black or phthalocyanine blue in advance and exposed to ultraviolet light, and colored at the same time as development is completed. Used for forming images.

The present invention will be explained below with reference to Examples.

Example 1 A water-swellable polymer membrane consisting of a mixed emulsion of 5 parts of a copolymer of polyvinyl acetate and methacrylic acid with a degree of saponification of 40% and 1 part of an aqueous solution of a 50% polyvinyl acetate emulsion was prepared by sandblasting, etc. A subbing layer is applied to a coating thickness of about 1 to 2 μm on the matte surface of the plastic sheet, which has been roughened by the process, and is dried. A 10% aqueous solution of 4-diazodiphenylamine salt and formaldehyde condensate was applied on the resulting film.
20 parts of 15% polyvinyl alcohol (degree of polymerization 1700,
In addition to a mixed emulsion of 60 parts (saponification degree 85%) and 40 parts of a 50% polyacrylic acid ester emulsion, an appropriate amount of water is added to prepare a diazo-based light-sensitive emulsion, which is coated and dried. The original document is placed on this photosensitive sheet and irradiated with ultraviolet rays, developed with water, immersed in a dyeing solution with the composition shown below for a predetermined period of time, and then washed with a 1% aqueous solution of nonionic surfactant to produce a clear black positive. An image was formed.

Composition of dyeing solution Acidic 1:1 type metal complex dye (Shibaran Black)
BGL) 4 parts water 96 parts Staining solution temperature 30°C Dyeing time 3 parts Example 2 As an undercoat layer, copolymer of hydroxyethyl acrylate and methyl methacrylate (90:10)
A water-swellable polymer film consisting of 30 parts of methyl cellosolve and 70 parts of methyl cellosolve is applied to a coating thickness of about 1 to 2 μm on the matte surface of a plastic sheet and dried. 15% polyvinyl alcohol aqueous solution (polymerization degree 2000, saponification degree 80
%) 40 parts of 50% polyvinyl acetate emulsion and 80 parts of mixed emulsion with 15 parts of carbon black.
and an appropriate amount of water, and 4-
A diazo-based light-sensitive emulsion is prepared by adding diazo-3-methoxydiphenylamine salt and 10 parts of a 10% aqueous solution of a formaldehyde condensate, and the emulsion is coated on the undercoat layer and dried. When the original document was placed in close contact with this photosensitive sheet, exposed to ultraviolet rays, and developed with water, a clear black image with strong adhesion and no background smudges due to adsorption of diazo components or pigments was obtained.

Example 3 A water-swellable polymer film of vinyl acetate-polymer emulsion was coated on the matte surface of a plastic sheet to form an undercoat layer to a thickness of about 1 to 2 μm, and dried, and then a diazo photosensitizer having the following composition was coated. , forming a photosensitive film. The original document is placed in close contact with this photosensitive sheet and exposed to ultraviolet rays, and developed with a composition of 12 parts phenyl cellosolve, 3 parts benzotriazole triethanolamine addition salt, 6 parts sodium isopropylnaphthalene sulfonate, and 250 parts water. After developing with a solution and washing with water, immersing it in a 5% aqueous solution of Pronsilan Black R (reactive black dye) for 3 minutes and washing with water, the optical density showed no coloration in the non-image areas.
A 2.8 black positive image could be formed on the sheet.

Composition of diazo photosensitive liquid: 2-hydroxy-phenoxypropyl methacrylate/methyl methacrylate/methacrylic acid/
Hydroxypropyl methacrylate/acrylonitrile copolymer (20/20/3.5/30/10) 10 parts Coupled product of paraformaldehyde condensate of 4-diazo-3-methoxy-diphenylamine and dodecylbenzenesulfonic acid 1 part Methyl cellosolve 90 parts

Claims (1)

[Claims] 1. A subbing layer of a water-swellable polymer film of 2μ or less is provided on a plastic sheet-like substrate, and a diazo-based photosensitive coating that is the same as the subbing layer or less swollen in water than the subbing layer is provided on top of that layer. A photosensitive sheet for forming colored images, characterized by: