JP2549014B2 - Photosensitive film for screen plate making - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a coating film that can be developed with water, is excellent in water resistance and solvent resistance, and can be printed with water-based ink, water-based pressure-sensitive adhesive, etc. The obtained photosensitive material for screen plate making is concerned.

[Prior Art] Screen printing is simple in plate making and printing, high in image accuracy, and large in ink thickness to be printed.
It has characteristics that it does not choose the material to be printed, and it is used in a wide variety of fields, and its applications are from printing of printing flags and posters to printing of solder resist and etching resist when making printed circuit boards. It is still expanding.
With the use in making printed circuit boards,
Increased performance requirements for screen printing plates, water resistance,
In addition to solvent resistance and abrasion resistance, higher precision and excellent printability have been required. In addition, water-based inks that do not contain organic solvents have come to be used due to problems such as occupational environment hygiene and pollution, and membrane switches have been introduced into various electronic devices, and water-based pressure-sensitive adhesives have been used for the spacers. Since it is also applied by screen printing, the screen printing plate is required to have high water resistance.

Conventionally, a method called a direct method in which a photosensitive resin is directly coated on a gauze has been mainly used as a method of screen-making. However, while this direct method can obtain an arbitrary film thickness by overcoating, it has a drawback that the workability is extremely poor because the application and drying of the photosensitive resin must be repeated, and it is also a problem. Since the smoothness of the surface of the flexible resin film is poor, printing reproducibility is poor due to ink bleeding and the like. Therefore, it is becoming difficult to meet the currently required printability and accuracy. As a screen plate making method for improving the drawbacks of the direct method as described above, a photosensitive composition is applied on a base film and dried to form a photosensitive film for screen plate making, and the film is water or a photosensitive composition. Stick it on the gauze using something
After drying, a method called a film method has been found in which a base film is peeled off to form a plate. By using this film method, the working process can be shortened, and a coating film having a uniform thickness can be obtained for screen printing, so that a plate with excellent accuracy can be obtained. No plate-making film having excellent water resistance and solvent resistance capable of printing has been found.

[Problems to be solved by the invention]

In the conventional photosensitive resin composition for screen plate making, the printing accuracy, whether using any of the direct method and the film method,
Due to insufficient water resistance and solvent resistance, swelling or elution causes stickiness on the plate. Further, in the plate by the conventional film method, since the water resistance is insufficient and the smoothness of the plate film is excessively high, the plate film completely adheres to the printing medium when the plate film swells in water, and particularly, the water-based ink, It has a drawback that it is not suitable for printing with an aqueous pressure-sensitive adhesive. That is, polyvinyl alcohol is used as a film-forming component in the photosensitive resin composition for screen plate making that has been conventionally used. Since this polyvinyl alcohol has many hydrophilic groups even if it is crosslinked with a photosensitizer such as a diazo resin, it swells with polar water or alcohol. When the polyvinyl alcohol, which is a film-forming component, swells, not only the film strength decreases, but also the film surface becomes tacky, the adhesion between the gauze and the plate film decreases, and the printing durability remarkably decreases.

In order to solve this point, some of the direct method photosensitive resin composition liquids include those in which the ratio of polyvinyl alcohol is extremely reduced, but the direct method plate made from this photosensitive resin composition liquid is The water developability is extremely poor, and it takes time to develop and there is a problem in terms of accuracy. This is due to the excessive hydrophobic polymer emulsion, which improves the water resistance, but when it is too large, the emulsions associate with each other, significantly deteriorating the water developability and causing clogging. To reduce the accuracy.

In the case of a non-polar solvent, the vinyl acetate emulsion that has been added to improve water resistance dissolves or swells to develop tackiness, reduces adhesion to gauze, and significantly reduces printing durability. .

[Means for solving problems]

The present inventors have earnestly studied to solve the above-mentioned problems, and have completed the present invention. The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and particularly to allow printing of water-based inks and water-based pressure-sensitive adhesives, the printing surface has a moderately rough surface, water resistance, solvent resistance, An object of the present invention is to provide a photosensitive material for screen plate making having excellent printing durability.

As a result of diligent research to solve such problems, in a photosensitive film for screen plate making, a printing surface layer (A composition layer) is formed on a base film, and an adhesive support layer (B composition layer) is formed thereon. We have found a water-developable photosensitive film for screen plate making, which has a laminated structure. The components of the printing surface layer (A composition layer) and the adhesive support layer (B composition layer) are shown below.

A composition layer: (a) polyvinyl alcohol or a polyvinyl alcohol derivative, (b) a photopolymerizable monomer having an ethylenically unsaturated bond in the molecule, a photopolymerization initiator, (c) a photocrosslinking agent, and (d). From a polyethylene polymer fine powder having a softening point of 100 ° C. or higher, a particle diameter of 1 to 20 μm and a density of 0.92 or higher, or a tetrafluoroethylene resin fine powder of a particle size of 1 to 20 μm, or a mixture of these two types of fine powders. And a photosensitive resin composition layer.

B composition layer: (a) polyvinyl alcohol or a polyvinyl alcohol derivative, (b) a photopolymerizable monomer having an ethylenically unsaturated bond in the molecule, a photopolymerization initiator, (c) a photocrosslinking agent, and (e) A photosensitive resin composition layer comprising a hydrophobic polymer emulsion.

The printing surface layer of the film of the present invention is (a), (b),
Water resistance of the photosensitive resin composition, which is composed of the components (c) and (d), and in particular the component (d) is a spherical polyethylene polymerization resistant or tetrafluoroethylene resin having excellent water resistance and solvent resistance. In addition to improving the properties and solvent resistance, it is possible to form appropriate irregularities on the film surface and prevent adhesion to the printing medium. When the added fine powder of the polyethylene polymer or tetrafluoroethylene resin is exposed on the film surface, a spherical shape is preferable in order to prevent the printed material from being scratched.

When the particle size of the fine powder of these polyethylene-based polymers or tetrafluoroethylene resin is less than 1 μm, the particle size is too small to form appropriate irregularities on the film surface. Also, 20 μm
The above is not suitable because the particle size is large, the resolution is poor, and the plate surface is too rough, causing the ink to bleed. Further, the softening point of the polyethylene-based polymer fine powder to be added is limited to 100 ° C. or higher. When the softening point is less than 100 ° C., the gastric ethylene polymer fine powder is softened in the drying step when the photosensitive resin composition is formed into a film, and appropriate unevenness cannot be formed on the film surface. Also,
A polyethylene-based polymer having a density of less than 0.92 is not preferable because it swells with a solvent.

On the other hand, the melting temperature of tetrafluoroethylene resin is about 300 ℃.
It is excellent in water resistance and solvent resistance with no problems in the drying process.

However, the softening point is 100 ° C or higher, and the particle size is 1 to 20 μm.
Addition of spherical polyethylene-based polymer with a density of 0.92 or more or fine powder of tetrafluoroethylene resin has the drawback that the film strength of the photosensitive resin film is slightly weakened or the adhesive strength with the gauze is reduced. Therefore, it is excellent as a printing surface, but is not suitable as an adhesive support layer. The adhesive support layer of the present invention is a photosensitive resin comprising polyvinyl alcohol or a polyvinyl alcohol derivative, a photopolymerizable monomer having an ethylenically unsaturated bond in the molecule and a photopolymerization initiator, a photocrosslinking agent, and a hydrophobic polymer emulsion. By applying the composition, it is possible to obtain a photosensitive film for screen plate making which is excellent in water resistance and solvent resistance, which is capable of preventing adhesion to a substrate to be printed without lowering film strength and adhesive strength with gauze. be able to.

The printing surface layer containing polyethylene-based polymer and tetrafluoroethylene resin fine powder is 10 to 40 μm, and the adhesive support layer without polyethylene-based polymer and tetrafluoroethylene resin fine powder is 10 to 200 μm. Is preferred. If the printing surface layer containing the fine particles of polyethylene polymer or tetrafluoroethylene resin is 40 μm or more, the light transmission of the polyethylene polymer or tetrafluoroethylene resin is poor, and the exposure time becomes very long. Practicality is reduced. In addition, when the adhesive support layer that does not contain fine particles of polyethylene-based polymer or tetrafluoroethylene resin is 10 μm or less, peeling of the plate film may occur during printing due to insufficient adhesive strength with the gauze, resulting in sufficient resistance. A printable plate cannot be obtained.

The above-mentioned polyvinyl alcohol and polyvinyl alcohol derivative are 5 to 70%, preferably 5 to 50% of the total solid content.
Use in the range of. If it is less than 5%, the water developability becomes poor,
When it is 70% or more, it is inferior in terms of polyhydric property.

Specific examples of the photopolymerizable monomer having an ethylenically unsaturated bond include pentaerythritol (meth) acrylate, dipentaerythritol hexa (meth) acrylate, tetramethylolmethane tri (meth) acrylate, and trimethylolpropane tri (meth). Acrylate, neopentyl glycol di (meth) acrylate, dibromoneopentyl glycol di (meth) acrylate, 2-hydroxyethyl (meth) acrylate,
2-hydroxyethyl (meth) acryloyl phosphate, dicyclopentanyl diacrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth) acrylate,
Examples thereof include phenylglycidyl (meth) acrylate, ethylene glycol diglycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, N-methylol (meth) acrylamide, (meth) acrylamide, and methylenebis (meth) acrylamide. The above "(meth) acrylate" means either methacrylate or acrylate. These photopolymerizable monomers having an ethylenically unsaturated bond are contained in the total solid content.
It is used in the range of 0.5 to 80%, preferably 5 to 70%. 0.5
If it is less than 80%, a plate having sufficient physical properties cannot be obtained, and if it is more than 80%, the product has poor storage stability.

As the photopolymerization initiator for the photopolymerizable monomer having an ethylenically unsaturated bond, acetophenone, benzophenone, benzoylmethyl ether, benzoylpropyl ether, Michler's ketone, di-t-butylanthraquinone, 2-chlorothioxanthone, 2,4 -Thioxanthone derivatives such as dimethylthioxanthone are used. These may be used alone or as a mixture of two or more kinds, and the additive is 0.1 to 15 parts, more preferably 0.5 to 10 parts with respect to 100 parts of the photopolymerizable monomer having an ethylenically unsaturated bond. Used in the range of parts.

Examples of the photo-crosslinking agent for the above-mentioned polyvinyl alcohol or polyvinyl alcohol derivative include diazo resins and the like. For this, a water-soluble diazo resin of an anion complex such as sulfate, phosphate, and zinc chloride double salt of p-diazodiamine-paraformaldehyde condensate can be used. Examples of this type of diazo resin include paraaminodiphenylamine, 4-amino-4'-methyldiphenylamine, 4-amino-4'-methoxydiphenylamine, and
A water-soluble diazo resin obtained by condensing a diazo compound of diphenylamines such as -amino-4'-nitrodiphenylamine with aldehydes such as paraformaldehyde and acetaldehyde can be used. These photo-crosslinking agents are used alone or in combination, and are added in the range of 0.5 to 15 parts, preferably 1 to 15 parts, based on the total solid content. If it is 0.5 parts or less, a photosensitive film having sufficient water resistance cannot be obtained, and if it is 15 parts or more, there is a problem that curing time is too long.

The softening point is 100 ° C. or higher, the particle size is 1 to 20 μm, and the density is 0.9.
2 or more spherical polyethylene-based polymer, fine powder of tetrafluoroethylene resin, 1 to 90% of the total solid content, preferably 5 to
Used in the range of 70%. If it is 1% or less, sufficient physical properties cannot be obtained, and if it is 90% or more, the resolution and accuracy are adversely affected, and the light transmission of the fine powder itself is poor, so that a curing time is required.

Specific examples of the hydrophobic polymer emulsion in the photosensitive resin composition used for the adhesive support layer include vinyl acetate polymer emulsion, ethylene-vinyl acetate copolymer emulsion, silicone resin emulsion, styrene-
Examples thereof include acrylic acid copolymer emulsions, acrylic vinegar-based emulsions, vinyl chloride chloride polymer emulsions, and vinylidene chloride polymer emulsions. These hydrophobic polymer emulsions are used in the range of 0.5 to 95%, preferably 5 to 70% of the total solid content. At 0.5%, the water resistance of the plate is poor, and at 95%, the product is poor in storage stability.

The base film is a polyester film,
A polypropylene film, a polyvinyl chloride film, an acetate film or the like is used.

The printing surface layer shown as the A composition layer and then the adhesive support layer shown as the B composition layer are applied on this base film, dried and laminated to form a photosensitive film for screen plate making of the present invention. To get

In addition to the components described above, a dye, a pigment, a plasticizer, a coatability improver and the like can be further added to the photosensitive film for screen plate making of the present invention, if necessary.

The photosensitive film for plate making of the present invention is a screen printing plate with a gauze, which is attached with water or hydroalcoholic alcohol and dried, and the base film is peeled off to form a screen printing plate having a photosensitive film. . Then, an image mask is applied to this printing plate and set in a vacuum baking frame, which is exposed using a metal halide lamp or the like, and developed using water. The obtained plate is used to print an aqueous ink, an aqueous pressure-sensitive adhesive or the like on a plastic film, a plastic plate, paper or the like.

〔The invention's effect〕

By using the photosensitive double-layer film for screen plate making of the present invention described above, even in the case of printing a water-based ink containing a polar solvent, a water-based pressure-sensitive adhesive, to prevent close contact with the substrate, plate separation A screen printing plate having excellent water resistance and solvent resistance can be obtained.

Example 1 Partially saponified polyvinyl alcohol having a saponification degree of 88 mol% and a polymerization degree of 1800 (“P-18” manufactured by Shin-Etsu Chemical Co., Ltd.) 40
Dissolve 0 g in 300 g of water, neopentyl glycol diacrylene (manufactured by Nippon Shokubai Chemical Co., Ltd.) 30 g, benzoyl isopropyl ether 1.2 g, high density polyethylene (Mitsubishi Chemical Co., Ltd. “JV070S” density, 0.967, softening point 1
(31 ° C.) and pulverized to a particle size of 1 to 3 μm, 40 g of fine powder and 20 g of a condensate of 4-amino-4′-methyldiphenylamine and paraformaldehyde are mixed by stirring to obtain a photosensitive resin composition (A). Was prepared. Saponification degree 88 mol%,
40 g of partially saponified polyvinyl alcohol (Shin-Etsu Chemical Co., Ltd. "P-18") having a degree of polymerization of 1800 is dissolved in 250 g of water, and neopentyl glycol diacrylate (manufactured by Nippon Shokubai Kagaku Co., Ltd.) 30 g, benzoyl isopropyl ether 1.2
80 g of ethylene-vinyl acetate copolymer emulsion ("Sumikaflex 400" manufactured by Sumitomo Chemical Co., Ltd.),
A photosensitive resin composition (B) was prepared by stirring and mixing 20 g of a condensate of 4-amino-4'-methyldiphenylamine and polaformaldehyde. A polyester resin film was coated with the photosensitive resin composition (A) in a thickness of 15 μm, and then the photosensitive resin composition (B) was coated in a thickness of 25 μm to form a 40 μm screen plate-making film.

This film was attached to a screen printing plate covered with a 150-mesh polyester film gauze using a mixed solution of water: isopropyl alcohol = 8: 2 and dried. When the polyester film was peeled off after drying, the thickness of the photosensitive film was 20 μm. An image mask with a line width of 200 μm was applied to this plate, which was set in a vacuum baking frame, and exposed for 180 seconds with a 3 kW metal halide lamp from a distance of 1 m. Then, after soaking in water at 20 ° C. for 2 minutes, it was completely developed with a water spray and dried. Using this plate, 10,000 sheets of water-based pressure-sensitive adhesive were printed on a polyester film without any problems.

Example 2 Partially saponified polyvinyl alcohol having a saponification degree of 88 mol% and a polymerization degree of 1800 (“P-18” manufactured by Shin-Etsu Chemical Co., Ltd.) 40
g is dissolved in 300 g of water, and neopentyl glycol diacrylate (manufactured by Nippon Shokubai Chemical Co., Ltd.) 30 g, benzoyl isopropyl ether 1.2 g, tetrafluoroethylene resin (Nitoflon PTFE manufactured by Nitto Denki Kogyo KK) ) Was pulverized to classify particles having a particle diameter of 1 to 3 μm, 40 g
A photosensitive resin composition (A) was prepared by stirring and mixing 20 g of a condensate of -amino-4'-methyldiphenylamine and paraformaldehyde. A polyester resin film was coated with the photosensitive resin composition (A) to a thickness of 20 μm, and the same photosensitive resin composition (B) as in Example 1 was coated thereon to a thickness of 60 μm to prepare an 80 μm screen plate-making film.

This film was attached to a screen printing plate covered with a 150-mesh polyester film gauze using a mixed solution of water: isopropyl alcohol = 8: 2 and dried. When the polyester film was peeled off after drying, the thickness of the photosensitive film was 60 μm. Apply an image mask with a line width of 500 μm to this plate and set it in a vacuum baking frame, a distance of 1 m or 3 kW
It was exposed with a metal halide lamp for 5 minutes. Then, after immersing in water at 20 ° C. for 2 minutes, it was completely developed with a water spray and dried.

This plate was used to print 10000 sheets of a water-based pressure-sensitive adhesive on a polyester film, but no problem occurred.

Example 3 Partially saponified polyvinyl alcohol having a saponification degree of 88 mol% and a polymerization degree of 1800 (“P-18” manufactured by Shin-Etsu Chemical Co., Ltd.) 40
g was dissolved in 350 g of water, and methosulfate of 1-methyl-4- (p-formylstyryl) pyridinium was added in an amount of 1.2 per mol of the constitutional unit of partially saponified polyvinyl alcohol.
Mol% and 0.15N phosphoric acid as an acid catalyst were added to carry out an acetalization reaction, and after the reaction, the mixture was neutralized with sodium hydroxide. 60 g of vinyl acetate polymer emulsion (“Movinyl 50M” manufactured by Hoechst Synthesis Co., Ltd., solid content 50%), 30 g of polyester acrylate (“Aronix 8100” manufactured by Toagosei Co., Ltd.), and t-butylperoxy were added to the reaction solution. A photosensitive resin composition (B) was prepared by mixing 0.4 g of carbonylbenzophenone with stirring, and the same photosensitive resin composition (A) as in Example 1 was prepared on the polyester film.
μm coated, and the photosensitive resin composition (B) is coated on top of it to 65 μm.
A film for screen making having a thickness of 80 μm was formed by coating with μm.

This film was attached to a screen printing plate covered with a 150-mesh polyester film gauze using a mixed solution of water: isopropyl alcohol = 8: 2 and dried. When the polyester film was peeled off after drying, the thickness of the photosensitive film was 60 μm. Apply an image mask with a line width of 500 μm to this plate and set it in a vacuum baking frame, and from the distance of 1 m, 3 k
It was exposed for 60 seconds with a W metal halide lamp. Then, it was soaked in water at 20 ° C. for 2 minutes and then completely sprayed with a water spray and dried.

Using this plate, 10,000 sheets of water-based pressure-sensitive adhesive were printed on a polyester film without any problems.

Example 4 Partially saponified polyvinyl alcohol having a saponification degree of 88 mol% and a polymerization degree of 18000 (“P-18” manufactured by Shin-Etsu Chemical Co., Ltd.)
40 g was dissolved in 350 g of water, and 1-methyl-4- (p-formylstyryl) pyridinium methosulfate was added to 1.
2 mol% and phosphoric acid 0.15N as an acid catalyst were added to carry out an acetalization reaction, and after the reaction, it was neutralized with sodium hydroxide. High-density polyethylene (“JV070S” manufactured by Mitsubishi Kasei Co., Ltd.), density 0.967, softening point 131
40 ° C.) and 40 g of fine powder obtained by classifying particles having a particle diameter of 1 to 3 μm, polyester acrylate (Toagosei Co., Ltd.)
30 g of "Aronix 8100" manufactured by the company) and 0.4 g of t-butylperoxycarbonylbenzophenone were stirred and mixed to prepare a photosensitive resin composition (A). A photosensitive resin composition (A) is coated on the polyester film in a thickness of 15 μm, and a photosensitive resin composition (B) similar to that in Example 3 is coated thereon in a thickness of 15 μm.
A 30 μm film for screen plate making was prepared by coating.

This film was applied to a screen printing plate covered with a 150-mesh polyester film gauze with a mixed solution of water: isopropyl alcohol = 8: 2 and dried. When the polyester film was peeled off after drying, the thickness of the photosensitive film was 10 μm. An image mask with a line width of 100 μm was applied to this plate, which was set in a vacuum baking frame and exposed for 40 seconds with a 1 m distance 3 kW metal halide lamp. Then, it was immersed in water at 20 ° C. for 2 minutes, completely developed with a water spray, and dried.

Using this plate, 10,000 water-based pressure-sensitive adhesives were printed on a polyester film without any problems.

Comparative Example 1 A film for screen making having a thickness of 40 μm was prepared by using the B layer except for the A layer of Example 1.

This film was attached to a screen plate coated with 150 mesh polyester gauze with a mixed solution of water: isopropyl alcohol = 8: 2, and dried. When the polyester film was peeled off after drying, the thickness of the photosensitive film was 20
μm. An image mask with a line width of 200 μm was applied to this plate, which was set in a vacuum baking frame, and exposed for 180 seconds with a 3 kW metal halide lamp from a distance of 1 m. Next, it was immersed in water at 20 ° C., completely developed with a water spray, and dried.

When a water-based pressure-sensitive adhesive was printed on a polyester film using this plate, the plate swelled after about 100 sheets and the plate to be printed and the plate began to adhere, and after printing 250 sheets, the photosensitive film peeled from the gauze. It became impossible to print at the beginning.

Comparative Example 2 A screen plate coated with 150 mesh polyester gauze was coated with a photosensitive resin composition having the same composition as in Comparative Example 1 using a bucket to form a 20 μm photosensitive film. An image mask having a line width of 200 μm was applied to this plate, which was set in a vacuum baking frame and exposed for 180 seconds with a 3 kW matal halide lamp from a distance of 1 m. Next, it was immersed in water at 20 ° C., then completely developed with a water spray and dried.

When a water-based pressure-sensitive adhesive was printed on a polyester film using this plate, the plate swelled after about 100 sheets and the plate to be printed and the plate began to adhere to each other, and printing became impossible after printing 300 sheets.

Claims (1)

(57) [Claims] 1. A photosensitive resin composition layer, which has a moderately rough surface represented by the following A composition layer on a base film and serves as a printing surface layer which prevents adhesion to a substrate to be printed, A water-developable photosensitive film A composition layer for screen plate making, which has a structure in which a photosensitive resin composition layer to be an adhesive support layer represented by the following B composition layer is laminated thereon; a) polyvinyl alcohol or a polyvinyl alcohol derivative, (b) a photopolymerizable monomer having an ethylenically unsaturated bond in the molecule, and a photopolymerization initiator, (c) a photocrosslinking agent (d) a softening point of 100 ° C. or higher, particles Diameter 1-20 μm, density 0.92
Photosensitive resin composition layer B composition layer comprising the above-mentioned fine powder of polyethylene polymer, fine powder of tetrafluoroethylene resin having a particle size of 1 to 20 μm, or a mixture of these two fine powders; ) Polyvinyl alcohol or a polyvinyl alcohol derivative, (b) a photopolymerizable monomer having an ethylenically unsaturated bond in the molecule, a photopolymerization initiator, (c) a photocrosslinking agent, and (e) a hydrophobic polymer emulsion. Resin composition layer.