JPH05100433A - Screen printing plate material and method for manufacturing screen printing plate - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a screen printing plate material which is water-developable and capable of printing a high-resolution image even when an aqueous ink is used, and a method for producing the screen printing plate. [Structure] A screen printing plate material, which is obtained by applying an aqueous dispersion containing a microgel having a polymerizable double bond as a main component to a screen printing plate mesh and drying it, and the plate material, Provided is a method for producing a water-developable screen printing plate which is irradiated with an active energy ray to form an image.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is water-developable,
The present invention relates to a screen printing plate material capable of printing a high-resolution image even with an aqueous ink and a method for producing the screen printing plate.

[0002]

2. Description of the Related Art Conventionally, a screen printing plate has been used in various fields because it has a feature that the plate surface is flexible or ink can be applied thickly.
Examples include pattern printing on scarves, clothes, shoes, etc., art printing, nameplate printing, curved surface printing on bottles, plastic containers, etc. Further, recently, it has been applied to printing on a printed circuit board and the like. In order to make a screen printing plate, a mesh for a screen printing plate made of a material such as silk, nylon, tetron, stainless steel, etc. is conventionally stretched on a screen frame, for example, an aluminum screen frame with high tension, and In addition, a photosensitive emulsion prepared by adding a diazo resin or the like as a photosensitizer to an emulsion consisting of a photosensitizer, for example, vinyl acetate resin or Poval resin, is applied onto the gauze and dried on the photoconductive layer to adhere the image-formed film to the film. Then, baking, water development and drying were carried out with a high pressure mercury lamp, an ultraviolet lamp or the like to form an image on the screen film. The screen printing plate on which an image is formed with the conventional water-developable photosensitive emulsion as described above has no problem when it is used with a so-called solvent type ink diluted with a solvent.

[0003]

Recently, as a screen ink, an aqueous ink that does not use an organic solvent is desired as a screen ink from the viewpoints of environmental pollution and its effect on health. However, in the method for producing a screen printing plate using the above-mentioned photosensitive emulsion, water-based development is possible, but water-based ink cannot be used because it has no water resistance.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that an aqueous dispersion containing a microgel having a polymerizable double bond as a main component is used as a photosensitive emulsion. It was found that the screen printing plate used, coated, dried, exposed with an active energy ray such as ultraviolet (UV), and water-developed had no problem even if an aqueous ink was used. That is, JP-A-02-26380
When a water-based dispersion containing a microgel having a polymerizable double bond as a main component as disclosed in Japanese Patent Publication No. 5 is used as a photosensitive emulsion, irradiation with active energy rays such as radiation (electron beam) and ultraviolet rays can be performed. It was found that the unexposed area was cured and water-developable, and there was no problem even if an aqueous paint was used as the screen ink. The microgel used in the present invention is characterized in that it has both a hydrophilic group and a polymerizable double bond on the surface of fine particles, and therefore it can be cured by irradiation with active energy rays and can be developed with water. Since the screen printing plate of the present invention uses an aqueous dispersion containing a microgel having a polymerizable double bond as a main component as a photosensitive emulsion for forming an image, it can be cured by irradiation with active energy rays. And, the uncured portion can be developed with water.

The microgel fine particles used as the main component in the present invention are characterized by being composed of a core portion called a core and a skin portion surrounding the nucleus called a shell. The core, which occupies most of the microgel particles, is made of lipophilic material and the shell is made of hydrophilic material, but water-based ink is used to crosslink by irradiation of active energy rays. Even if it swells, a screen printing plate having good water resistance can be prepared.

As the material of the screen mesh used in the printing plate of the present invention, generally used silk, nylon, tetron, stainless steel, nickel, etc. can be used. The above materials are woven, plated or etched. It is created by performing processing such as forming a porous sheet. When the screen mesh is used as a printing plate, it can be used as a flat screen or a rotary screen plate. The rotary screen plate is one in which the screen printing plate has a cylindrical shape, and as the screen mesh used therefor, a metallic one is often used, and one made of stainless steel or amorphous metal fiber (basic composition Co- Fe-C
r-Si-B type), for example, manufactured by Unitika Ltd. under the trade name “Bolfa”, or a metal screen mesh containing nickel as a main component, for example, Stokes under the trade name “High Mesh”, also large. You can also use the product name "Alpha Screen" manufactured by Nippon Screen Co., Ltd.
Such a screen mesh is generally 40 to 500 mesh, preferably 80 to 400 mesh.

Next, the microgel aqueous dispersion used in the present invention will be described in more detail. The microgel aqueous dispersion used in the present invention can be produced by the same method as that disclosed in JP-A-02-263805. That is, a compound having a polymerizable double bond (composition of the core part)
First, microgel fine particles (A) are synthesized by emulsion polymerization using a quaternary ammonium salt-containing compound (composition of shell portion) as an emulsifier. Then, the compound (B) having at least one polymerizable double bond in one molecule and having an epoxy group that reacts with the quaternary ammonium salt is reacted with the quaternary ammonium salt of the microgel fine particles (A). Then, a microgel having a double bond is produced.

As the compound having a polymerizable double bond constituting the core portion, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
C1 to C18 alkyl ester of (meth) acrylic acid such as isopropyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, and lauryl (meth) acrylate: glycidyl ( (Meth) acrylate: C2-C20 alkenyl ester of (meth) acrylic acid such as allyl (meth) acrylate: hydroxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) C2 to C20 hydroxyalkyl ester of (meth) acrylic acid such as acrylate: allyloxylethyl (meth)
C3 to C19 alkenyloxyalkyl ester of (meth) acrylic acid such as acrylate: (meth) acrylic acid,
Trimethylolpropane tri (meth) acrylic acid ester, glycol di (meth) acrylic acid ester, polyol di (meth) acrylic acid ester, polyurethane di (meth) acrylic acid ester, chain extension with urethane bond Examples thereof include hydroxyethyl (meth) acrylate adduct of terminal isocyanate, di (meth) acrylic acid ester of polyester, butadiene, isoprene, chloroprene, and divinylbenzene.
These compounds may be used alone or in combination of two or more.

The quaternary ammonium salt-containing compound for constituting the shell portion is effective as an emulsifier and is usually a compound having a tertiary amino group neutralized with an acid to be quaternized. Is. Among such emulsifiers, examples of low molecular weight emulsifiers include dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, diethyllaurylamine, diethylmyristylamine, diethylpalmitylamine, diethylstearylamine, and the like. C2
0 Tertiary amine salts of reactive monomers having amino groups such as alkyl or alkenyl tertiary amines, 2,2'-dimethylaminoethyl (meth) acrylate, 2,2'-diethylaminoethyl (meth) acrylate, nitric acid, There are reaction products with acids such as sulfuric acid, acetic acid, propionic acid, butyric acid, and (meth) acrylic acid, and as polymeric emulsifiers, 2,2'-dimethylaminoethyl (meth) acrylate and 2,2'-diethylaminoethyl Reactive monomers having amino groups such as (meth) acrylate and other reactive monomers, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate,
C1 to C18 alkyl ester of (meth) acrylic acid such as butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, and lauryl (meth) acrylate: glycidyl (meth) acrylate: allyl (meth ) C2 of (meth) acrylic acid such as acrylate
C8 alkenyl ester: hydroxyethyl (meth)
C2-C8 hydroxyalkyl ester of (meth) acrylic acid such as acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate: (meth) acryl such as allyloxylethyl (meth) acrylate C3 to C19 alkenyloxyalkyl esters of acids:
Examples thereof include those obtained by copolymerizing with one or more vinyl monomers selected from (meth) acrylic acid and the like, and then neutralizing with an acid.

Further, there may be mentioned a polymer obtained by neutralizing an amino group-containing polymer such as a natural polymer such as chitosan or a synthetic polymer such as polyethyleneimine with an acid. These polymeric emulsifiers are used as they are or as a reactive emulsifier by introducing a double bond by reacting a part of the quaternary ammonium salt with a compound containing an epoxy group such as glycidyl (meth) acrylate and a quaternary ammonium salt. Can also be used. The polymeric emulsifier can control the degree of water solubility, and is therefore a preferred emulsifier in applications requiring water resistance. Further, for the purpose of assisting the emulsification, a cationic or nonionic low-molecular-weight surfactant may be used in combination with the above-mentioned polymer emulsifier as long as the physical properties such as water resistance are not impaired. These emulsifiers are used in an amount of 0.1 to 80% by weight, preferably 3 to 50% by weight, based on the compound having a polymerizable double bond, and the temperature of emulsion polymerization is 50 to 95 ° C, preferably
65-80 ° C. In the emulsion polymerization, the solid content of the compound having a polymerizable double bond and the emulsifier is 10 to 50% by weight, preferably 10 to 35% by weight.

In the present invention, the particle size of the microgel produced by emulsion polymerization is usually measured by the light scattering method.
10 to 500 nm. The quaternary ammonium salt present on the surface of the microgel fine particles (A) thus produced is reacted with the compound (B) having an epoxy group and at least one polymerizable double bond in one molecule, A polymerizable double bond is introduced on the surface of the microgel fine particles. Examples of the compound (B) include glycidyl (meth) acrylate, N-glycidyl (meth) acrylate, glycidyl allyl ether, epoxy compounds having an unsaturated double bond such as 1,2-epoxy-5-hexene, and glycidyl cinnamate. Etc. These compounds (B) are appropriately selected according to the desired physical properties and may be used alone or in combination of two or more. The reaction can be performed at a free ratio of 1 to 100 mol% with respect to the quaternary ammonium salt on the surface of the microgel particles. This reaction is carried out by mixing an epoxy compound with an aqueous dispersion of microgel at a temperature of 30 to 90 ° C, preferably 60 to 80 ° C.
Just stir for more than an hour to finish. As described above, in the present invention, there is an advantage that the reaction can be performed even in the aqueous dispersion.

In the present invention, an aqueous resin or a compound having a hydrophilic monomer bond may be mixed with the microgel aqueous dispersion within the range not impairing the gist of the invention. The mixing ratio of the water-based resin is preferably 0 to 30% by weight, more preferably 0 to 20% by weight. As the water-based resin, polyvinyl alcohol, carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, poly (meth) acrylic acid, casein, gelatin, starch, polyvinylpyrrolidone, poly (meth) acrylic acid amide, chitosan, quaternary ammonium salt-containing polymer, etc. Can be mentioned. Examples of hydrophilic monomers are N, N-methylenebis (meth) acrylamide, 1,2-di (meth) acrylamide ethylene glycol, N, N-oxymethylenebisacrylamide, (meth) acrylamide, vinylpyrrolidone, 2-hydroxy. Ethyl (meth) acrylate,
Examples thereof include polyoxyethylene (meth) acrylate and polyoxyethylene di (meth) acrylate. The microgel-based aqueous dispersion produced as described above is crosslinked by EB irradiation even without a photopolymerization initiator. Is promoted. As the photopolymerization initiator, benzophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl) 2-hydroxy-
2-Methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl] 2-morpholinopropanone and the like can be mentioned. The amount of these photopolymerization initiators added is within the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the resin. Also,
If necessary, colorants, extender pigments, plasticizers, stabilizers, defoamers, antioxidants, preservatives and the like can be added.

Image formation is carried out using the microgel aqueous dispersion thus obtained. In the image forming method, first, a screen printing plate mesh is coated with the coating liquid containing the microgel aqueous dispersion as a main component and then dried (screen printing plate material). If necessary, the coating and drying steps may be repeated several times for coating. In this way, the holes of the screen plate are filled with the resin composition containing the microgel as a main component, and then a negative film is brought into close contact with the resin composition and UV irradiation or EB irradiation is performed. After that, the negative film is peeled off, water is sprayed on the screen printing plate material, and the uncured resin is washed away, so that the cured portion becomes an image.

[0014]

EXAMPLES The present invention will be described in more detail below with reference to examples. In addition,
In the examples, "part" means "part by weight". (Example 1) (a) Preparation of cationic polymer emulsifier 100 parts of lauryl methacrylate, 100 parts of 2-dimethylaminoethyl methacrylate, and 200 parts of 2-propanol were stirred in a 2 liter reaction vessel while stirring in a nitrogen atmosphere at 80 ° C. Heated to. 1.6 parts of azobisisobutyronitrile (hereinafter abbreviated as AIBN) was added, and the mixture was kept for 2 hours. Then AIBN 0.
After adding 4 parts, the reaction mixture was kept at 80 ° C. for 4 hours to complete the polymerization. After cooling to room temperature, 38.2 parts of acetic acid and 1000 parts of water were added and heated to remove 2-propanol and water by azeotropic distillation. Then, 9.0 parts of glycidyl methacrylate was added, and the mixture was heated to 70 ° C. in an air atmosphere and held for 2 hours to obtain a cationic polymer emulsifier having pendant methacryl groups. (B) Synthesis of photosensitive microgel 50 parts 2-ethylhexyl methacrylate, 250 parts aqueous solution of cationic polymer emulsifier synthesized in (a) (solid content 20
%) In a 500 ml reaction vessel with stirring in a nitrogen atmosphere at 80 ° C.
Heated to. Then, 10.6 parts of a 3% 2,2-azobis (2-amidinopropane) dihydrochloride (hereinafter abbreviated as AAPD) aqueous solution was added and maintained for 2 hours, and then 2.7 parts of a 3% AAPD aqueous solution was added. After the addition was completed, the reaction mixture was kept at 80 ° C. for 4 hours to complete the polymerization. The particle size measured by the light scattering method is about 11
It was 0 nm. The resulting microgel aqueous dispersion was cooled to room temperature and left overnight, then glycidyl methacrylate 16.3
Parts were added and heated to 80 ° C. under air. Reaction mixture at 70 ° C
The reaction was completed by holding it for 2 hours to obtain a photosensitive microgel aqueous dispersion having a polymerizable double bond on the surface.
To this photosensitive microgel aqueous dispersion, 2.0 parts of Darocur 2959 (manufactured by Merck) as a photoinitiator was added and dissolved,
On a metal screen gauze "High Mesh 305 (manufactured by Stokes)" stretched over an aluminum frame, apply and dry so that the holes of the screen gauze are completely filled,
A screen printing plate material was obtained.

(Example 2) In Example 1, instead of 50 parts of 2-ethylhexyl methacrylate, 45 parts of lauryl methacrylate and ethylene glycol dimethacrylate were used.
A screen printing plate material was obtained in the same manner as in the example except that 5 parts were used.

(Example 3) R-45ACR-LC (polymethadiene modified product of polybutadiene manufactured by Idemitsu Petrochemical Co., Ltd.) was used.
50 parts, Emulgen 810 (polyoxyethylene octyl phenyl ether manufactured by Kao Corporation: low molecular surfactant)
2.5 parts, 200 parts of the aqueous solution of the cationic polymer emulsifier synthesized in (a) (solid content 20%), and 100 parts of deionized water were heated to 80 ° C. in a 500 ml reaction vessel under stirring in a nitrogen atmosphere. 3% AAPD
8 parts of the aqueous solution was added and kept for 2 hours. Then 3% AAPD aqueous solution
Two parts were added. After the addition was completed, the reaction mixture was kept at 80 ° C for 4 hours to complete the polymerization. The measurement result of the particle diameter by the light scattering method was about 200 nm. After leaving this microgel aqueous dispersion overnight, 2.7 parts of glycidyl methacrylate was added, and the mixture was heated to 70 ° C. in an air atmosphere and held for 2 hours to obtain a photosensitive microgel aqueous dispersion. To this photosensitive microgel aqueous dispersion, 2.0 parts of Darocur 2959 as a photoinitiator was added and dissolved, and then a screen printing plate material was obtained in the same manner as in Example 1.

(Comparative Example 1) A screen printing plate material was obtained in the same manner as in Example 1, except that a diazo photosensitive resin having the following composition was used. Diazo photosensitive resin composition-Polyvinyl alcohol (saponification degree 88%, average degree of polymerization 1400) 10 parts-Vinyl acetate emulsion (solid content 50 wt%) 40 parts-Water 60 parts-Diazo resin 1.5 parts

(Evaluation of water developability) The screen printing plate materials obtained in Examples 1 to 3 and Comparative Example 1 are irradiated with UV through a negative film. For development, after exposure, spray water for 2 minutes. After development, remove water sufficiently and then at 60 ℃
Dry in the oven. In the evaluation, the presence or absence of residual resin (undeveloped resin) in the unexposed portion and the presence or absence of image defects in the exposed portion were visually determined.

(Water resistance evaluation) Examples 1 to 3 and Comparative Example 1
10mm × 50mm × 0.1mm film was made from the photosensitive material of No.1 by the casting method, and the film was immersed in a mixed solvent of deionized water, deionized water / isopropyl alcohol (hereinafter abbreviated as IPA) = 1/1 for 24 hours. The swelling rate of
Water resistance was evaluated. The swelling ratio was calculated by ((weight after immersion for 24 hours / weight before immersion) -1) x 100. Table 1 shows the results of water developability and water resistance.

[0020]

[Table 1]

As described above, by using the microgel, a screen printing plate capable of being developed with water and having excellent water resistance could be obtained.

Claims (2)

[Claims] 1. A screen printing plate material comprising a screen printing plate mesh coated with an aqueous dispersion containing a microgel having a polymerizable double bond as a main component and dried. 2. A screen printing plate mesh is coated with an aqueous dispersion containing a microgel having a double bond as a main component,
A method for producing a water-developable screen printing plate, which comprises irradiating a dried screen printing plate material with an active energy ray to form an image.