JPS597089B2 - Plate making method for lithographic printing plates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for making a lithographic printing plate by a photochemical method.

Conventionally, plate materials for lithographic printing have been used, such as plate materials (PS plates), which are made by applying lipophilic resins such as diazonium salts to metal plates that have been given water-retention properties by graining or anodic oxidation.
was common.

Such plate materials have various defects, and improvements thereto have been strongly desired by those skilled in the art. That is, the commonly used Al plates are not only expensive, but also require a great deal of labor and time to perform graining or anodic oxidation to impart water retention properties, making them uneconomical. Furthermore, the diazonium salts used in the photosensitive liquid are hazardous substances, and great efforts and care were required to manage the health and safety of workers. The present inventors have conducted extensive research with the aim of eliminating all of the above-mentioned defects and providing a lithographic printing plate that is inexpensive, has low toxicity, and has excellent image reproducibility and printability. , which led to the completion of the present invention.

That is, in the present invention, the total amount of carbon-carbon double bonds and/or hydrogen groups bonded to tertiary carbon is O, 05m
A photosensitive layer containing 5% by weight or more of a hydrophilic radically polymerizable compound as an essential component is provided on the surface of a lipophilic base material whose main component is a lipophilic resin having a weight of 5% by weight or more, and then placed on the photosensitive layer. A process for making a lithographic printing plate, which is characterized by applying actinic rays through a positive film to impart a hydrophilic radically polymerizable compound to non-image areas, and then developing with a cleaning solution mainly containing water. It is.

In the present invention, a hydrophilic radically polymerizable compound in a photosensitive layer supported on an easily available and inexpensive lipophilic base material is added to the surface of the lipophilic base material using actinic rays through a positive lithium film. A hydrophilic surface, which is the image area, is formed, and the hydrophilic radically polymerizable compound that could not be added to the surface of the lipophilic base material due to unexposed light is removed with a cleaning solution mainly composed of water. This is a plate-making method that consists of exposing the surface of the lipophilic base material itself. Conventionally, a method of attaching a lipophilic image area to a hydrophilic substrate by a photochemical method has been common, but as described above, the present invention is fundamentally different in concept from the conventional method. This makes it possible to easily produce plates that are inexpensive, have little toxicity, and have excellent image reproducibility and printability. The lipophilic resin used in the present invention is one that has sufficient liposensitivity to the lithographic printing ink used during printing and to which a hydrophilic radically polymerizable compound can be added by irradiation with actinic rays. .

Specifically, for example, diene homopolymers such as () polyptadiene, polyisoprene, and polypentadiene; styrene, (meth)acrylic acid esters, etc. containing diene monomers such as butadiene, isoprene, and pentadiene as one component; Binary or multicomponent copolymers with (meth)acrylonitrile, etc.; Unsaturated polyester; Unsaturated polyepoxide: Unsaturated polyacrylic: Linear or tertiary polymers with one carbon-carbon double bond in the molecule, such as high-density polyethylene (11) 1-substituted olefins such as styrene, propylene, vinyl chloride, acrylonitrile, acrylic acid, acrylic esters, alkyl vinyl esters, and vinyl carbazole, and 1-2- such as maleic acid, fumaric acid, and crotonic acid. A homopolymer or a copolymer of a di-substituted olefin; a combination of the 1-substituted olefin and/or the 1,2-disubstituted olefin with a 1,1-disubstituted olefin such as methacrylic acid, methacrylic acid ester, methacrylonitrile, isobutyne, etc. Copolymers; condensation polymers such as polyepoxides, polyurethanes, and polyamides; linear or three-dimensional polymers that have hydrogen groups bonded to tertiary carbons in their molecules, such as natural polymers such as cellulose derivatives etc. can be mentioned. These resins can be used alone or in a mixture of two or more. At this time, the total amount of carbon-carbon double bonds and/or hydrogen groups bonded to tertiary carbon contained in the molecule is 0.05m01A
It needs to be 9 or more, preferably 0.1 m01/Kg or more. Carbon-carbon double bond and/or
The total amount of hydrogen groups bonded to tertiary carbon is 0.05m01A
If the lipophilic resin contains less than 100 g, the amount of the hydrophilic radically polymerizable compound added by irradiation with actinic rays is insufficient, and the surface hydrophilicity is insufficient. Pigments, dyes, fillers, curing agents, plasticizers, photosensitizers, and the like can be added and dispersed to these lipophilic resins to form lipophilic base materials.

To produce a regular lipophilic substrate using lipophilic resins, they are usually formed into a sheet.

In order to form a sheet, it is also possible to use a method such as extrusion of the heated, softened and melted film, but it is also possible to form a film by extrusion or other methods. A film can also be formed by coating or scattering a resin on the surface of a sheet-like support and, if necessary, subjecting it to a curing and crosslinking treatment. Examples of the support for the lipophilic resin constituting a part of the lipophilic base material include paper, plastic film, cloth, and metal foil.

The thickness of the lipophilic resin when formed into a film is usually 5 to 200 mm.
The thickness is preferably 0μ, preferably 8 to 40μ when using a support by coating or spraying, and 50 to 1000μ when forming a film without using a support. A sheet-like support can also be laminated after film formation. In the present invention, the photosensitive layer on the surface of the lipophilic base material contains a hydrophilic radically polymerizable compound of 5% by weight or more as an essential component, and if necessary,
6% by weight or less of solvent, 10% by weight or less of photosensitizer, 5% by weight or less of radical polymerization inhibitor, 40% by weight or less of radical polymerizable compound, 40% by weight or less of polymer solidifying agent,
It is formed from a composition (hereinafter referred to as "photosensitive layer composition") which contains a thixotropic agent of 5% by weight or less, a surfactant of 5% by weight or less, and the like.

Pigments, dyes, fillers, etc. can also be used in combination with this photosensitive layer composition. Here, if the hydrophilic radically polymerizable compound is less than 5% by weight, the concentration of the hydrophilic radically polymerizable compound in the photosensitive layer is low, making it difficult to impart hydrophilicity necessary for lithographic printing to the lipophilic base material. Have difficulty. The hydrophilic radically polymerizable compound used in the present invention is a compound whose homopolymer is soluble in water or an electrolyte aqueous solution and/or exhibits swelling property of at least 10% or more in water or an electrolyte aqueous solution, and which Alternatively, by coexisting with a photosensitizer, it can be added to a lipophilic base material by irradiation with light in the absorption wavelength region.

For example, (meth)acrylic acids; 2-hydroxyethyl (meth)acrylate, diethylene glycol mono(
meth)acrylate, triethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, glycerol mono(meth)acrylate, polyethylene glycol di( meth)acrylate (the molecular weight of polyethylene glycol is 300 or more), 2-dimethylaminoethyl (meth)acrylate, 2-dimethylaminopropyl (meth)acrylate, 2-sulfoethyl (meth)acrylate, 3-sulfopropyl (meth)acrylate, 2-phosphoric acid ethylene (meth)acrylate, 2-
(Meth)acrylic acid esters such as phosphoric acid-1-chloromethylethylene (meth)acrylate; N-vinylimidazole, vinylpyridine, N-vinylpiperidone,
Vinyl compounds such as N-vinylcaprolactam and N-vinylpyrrolidone; Styrene sulfonic acids; Maleic acids such as (anhydrous) maleic acid, methyl (anhydrous) maleic acid, and phenyl (anhydrous) maleic acid; maleimide, methylmaleimide, phenyl Maleimides such as maleimide;
(meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-butyl (meth)acrylamide, N-2-hydroxyethyl (meth)acrylamide, N- N-methylenebis(meth)acrylamide, N-methylol(meth)acrylamide, (meth)
Examples include (meth)acrylamides such as acrylmorpholine, N-propyloxy(meth)acrylamide, N-N-dimethyl(meth)acrylamide, N-N-diethyl(meth)acrylamide, and diacetone acrylamide; one of these A species or a combination of two or more species may be used. The photosensitizer used in the present invention is a triplet sensitizer with a triplet energy of 50 Kca1/MOl or more or one that generates free radicals by actinic rays,
A known one is used.

For example, acyloins such as benzoin and acetoin;
Acilloin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, anisoin ethyl ether, pivaloin ethyl ether; α-monosubstituted acyloins such as α-methylbenzoin and α-methoxybenzoin; naphthoquinone, anthraquinone, etc. quinones, aromatic ketones such as benzophenone and acetophenone; substituted aromatic ketones such as Michler's ketone and hydroxybenzophenone; azobisisobutyronitrile, 2-cyano-2-propylazoformamide, 2-cyano-2 - Azo compounds such as butylazoformamide; metal salts such as uranyl nitrate and ferric chloride are suitable, and mercaptans, disulfides, halogen compounds, dyes, etc. can also be used. In the present invention, a known radical polymerization inhibitor is used to inhibit dark reactions, particularly dark reactions in the photosensitive layer.

Examples include hydroquinone, 2,4-tert-butylhydroxytoluene, N-N diphenylnitrosamine, and the like. The radically polymerizable compounds used in the present invention are commonly used compounds such as styrene, vinyltoluene, and (meth)acrylic acid esters. In the present invention, a known polymer solidifying agent is used for the purpose of maintaining the solid state of the photosensitive layer or for the purpose of adjusting the viscosity when the photosensitive layer composition is liquid, that is, when used as a photosensitive liquid. Examples include polyvinyl alcohol, polyvinyl acetate, cellulose derivatives, gelatin, pectin, acrylic copolymers, polyvinylpyrrolidone, polyethyleneimine, and the like. For the same purpose, thixotropic agents such as condensates of polyhydric alcohols and benzaldehyde or metal soaps can also be used. In the present invention, the solvent is mainly used when the photosensitive layer composition is used in a liquid state, that is, as a so-called photosensitive liquid.

As the solvent, a known solvent that dissolves the hydrophilic radical polymerizable compound, polymer solidifying agent, photosensitizer, etc., does not dissolve the lipophilic base material, and does not inhibit or suppress radical polymerization is used. Although there are no particular limitations, a solvent with a boiling point of 60 to 150° C. is desirable in order to maintain a desirable drying process of the photosensitive liquid. For example, alcohols, esters,
Single or mixed solvents such as ketones, ethers, aromatic compounds, and water are used. In the present invention, in order to provide a photosensitive layer containing a hydrophilic radically polymerizable compound on the surface of a lipophilic base material, if the photosensitive layer composition is non-liquid, it may be melted and applied onto the lipophilic base material and cooled; The photosensitive layer composition is dissolved in the above-mentioned solvent and applied onto a lipophilic base material, and then the solvent is evaporated and dried to form a photosensitive layer. On the other hand, when the photosensitive layer composition is a liquid so-called photosensitive liquid, the photosensitive layer is formed by coating and drying as is. Methods for applying the photosensitive layer composition solution onto the lipophilic substrate include dip coating, spray coating, curtain flow coating, roll coater coating, flow coating, tampon coating, brush coating, and foil coating. Conventional methods such as painting are used. Another method of providing a photosensitive layer on a lipophilic substrate is to laminate a preformed photosensitive layer onto the lipophilic substrate. In either method, it is desirable to provide a continuous photosensitive layer. The thickness of the photosensitive layer provided on the lipophilic base material surface is not particularly limited, but the dry film thickness is 0.2 to 2000.
μ, preferably 0.5 to 500 μ.

If it is less than 0.2μ, it is difficult to provide a hydrophilic non-image area on the lipophilic base material, and if it exceeds 2000μ, it is not only not economically advisable but also the efficiency of light irradiation decreases, which is undesirable. .

In order to make a plate using the lithographic printing plate material obtained in this way, a positive film is closely attached on the photosensitive layer, active light is irradiated through the positive film, and after the positive film is peeled off, a film is applied onto the lipophilic base material. A plate is prepared by washing with a water-based cleaning solution to form a lipophilic image area and a hydrophilic non-image area on the lipophilic base material.

Further, it is also possible to make a plate from the photosensitive layer composition coated on the lipophilic base material while it is in a liquid state. In this case, a transparent film is placed over the liquid photosensitive layer, a positive film is placed on top of the transparent film, and then active light is irradiated. The active light used preferably has a wavelength in the range of 250 nm to 700 nm, and more preferably a wavelength range that does not cause deterioration of the lipophilic base material.

Examples of the light source include low-pressure mercury lamps, high-pressure mercury lamps, fluorescent lamps, xenon lamps, carbon arc lamps,
Use a selection of tungsten incandescent lamps and sunlight. The irradiation time of actinic rays depends on the purpose, but is from several seconds to 10 minutes. Although the lithographic printing plate obtained by the present invention is very inexpensive and has low toxicity, it has excellent image reproducibility and printability, and can be widely used in the printing industry and office equipment industry. It is something.

Next, the present invention will be explained in more detail with reference to Examples, but the patent scope of the present invention is not limited thereby.

Example 1 100 parts by weight of 1,4-polybutadiene (manufactured by Nippon Zeon Co., Ltd., trade name "LCB-150", average molecular weight 5500) was dissolved in 300 parts by weight of Minelano V Spirit, and 0.15 parts by weight as metal cobalt was dissolved. A lipophilic resin composition was obtained by adding a corresponding amount of cobalt naphthenate.

Then, this composition was applied to a width of 1 m, a length of 50 m, and a thickness of 0.15 m.
A film of 40μ thick was coated on one side of an aluminum plate with a roll coater at a speed of 10 m/min, and then heated and cured at 50°C for 1 minute and 200-210°C for 3 minutes to form a lipophilic group. Material A was obtained. Next, 40 parts by weight of maleic anhydride and a styrene-maleic anhydride copolymer (
A solution of the photosensitive layer composition in which 3 parts by weight (molecular weight 5000) was dissolved in 100 parts by weight of acetone was applied to the polybutadiene surface of the lipophilic base material A at a speed of 10 m/min using a curtain flow coater, and dried at 60°C for 2 minutes. A plate material was prepared by providing a photosensitive layer with a thickness of 2 μm.

The obtained plate material was cut into a B4 size, and a positive film of a printing resolution test chart was placed in close contact with the plate material, and a lithographic exposure device (manufactured by Fuji Photo Film Co., Ltd., product name "PLA") was cut.
A latent image was formed by applying a hydrophilic radically polymerizable compound to the non-image area by exposing the plate material for 5 minutes using a NOPSPRINTERA3 chemical lamp equipped with an irradiation light energy density of 15 W/m''. The unexposed hydrophilic radically polymerizable compound was removed by washing with tap water containing % by weight of polyethylene glycol nonyl phenyl ether for 5 minutes.After drying the plate with hot air, it was placed on a tabletop offset rotary printing press and then placed on a tabletop offset rotary printing press for 2 minutes. As a result of trial printing using water containing % by weight of glycerin as dampening water, the resolution was 6 lines/Mml and the printing life was over 50,000 sheets.
Even after storage for several months, there was no change in resolution or printing durability.
Example 2 Epoxidized polybutadiene (trade name "Nitsso PB-BF")
100 parts by weight of "lOOO", manufactured by Nippon Soda Co., Ltd., 1/2 monopolymer type, average molecular weight 1000, degree of epoxidation approximately 30%), 30 parts by weight of trimellitic anhydride, and 13 parts by weight of benzophenone, dissolved in 350 parts by weight of dioxane. This composition was coated on one side of a 100 μm polyester film with a roll coater at a speed of 10 m/min to form a coating film with a thickness of 40 μm, and then coated at 500C for 1 minute and at 140°C for 2 hours.
A lipophilic base material B was obtained by heating and curing for a minute.

Next, 20 parts by weight of acrylamide, 1 part by weight of diethanolamine, and polyvinylpyrrolidone (with a molecular weight of about 1000
0) 2 parts by weight and 0.01 parts by weight of hydroquinone were dissolved in 100 parts by weight of methanol, and coated on the polybutadiene surface of lipophilic base material B at a speed of 10 m/min using a curtain flow coater, and dried at 60°C for 2 minutes. A plate material was prepared by providing a 2 μm photosensitive layer. The obtained plate material was cut into B4 size, exposed, washed out and trial printed in the same manner as in Example 1. As a result,
Resolution is 10 lines/M77! ．． The printing life was more than 50,000 sheets. Furthermore, the obtained plate material had a shelf life of more than one month at 40°C. Example 3 Polypropylene (trade name: "Mitsubishi Noblen 5020" manufactured by Mitsubishi Yuka Co., Ltd.) was heated with a hot roll with a surface temperature of 240°C, and then pressed using a press machine to form a material with a width of 1 m, a length of 10 m, and a thickness of 100 m.
A lipophilic base material C was obtained by molding it into a μ sheet shape.

Then, 20 parts by weight of N-methylolacrylamide, N
-N'-methylenepisacrylamide 1 part by weight, hydroxypropyl methylcellulose phthalate (molecular weight approximately 5
000) 3 parts by weight, 1 part by weight of Michler's ketone and N
-N-diphenylnitrosamine (0.05 parts by weight) was dissolved in 100 parts by weight of ethyl alcohol, and the resulting solution was applied to the lipophilic base material C with a whiter coat, and dried at room temperature for 30 minutes to form a 2μ photosensitive layer. The plate material was created using

The obtained plate material was exposed, washed out, and trial printed in the same manner as in Example 1. As a result, the developability was 10 lines/Mml, and the printing durability was 50,000 sheets or more. In addition, the storage stability of the obtained plate material was 40°C.
It lasted for over a month. Example 4 Triethylene glycol monomethacrylate 40k, 2
- A solution obtained by mixing and dissolving phosphoric acid ethylene methacrylate 407, benzophenone 37 and methyl cellosolve 207 was applied to the lipophilic base material C obtained in Example 3 to a thickness of about 1 to 2 μm, and then a 9 μm thick solution was applied. A Tetron film was placed over the film, and a positive film of a resolution test chart for lithographic printing was placed on top of the film. Exposure, washing, and trial printing were performed in the same manner as in Example 1. As a result, the resolution was 6 lines/MTL, and the printing durability was as follows. It was over 50,000 pieces.

Claims (1)

[Claims] 1 5% by weight on the surface of a lipophilic base material whose main component is a lipophilic resin having a total amount of carbon-carbon double bonds and (or) hydrogen groups bonded to tertiary carbon of 0.05 mol/kg or more. A photosensitive layer containing the above hydrophilic radically polymerizable compound as an essential component is provided, and then active light is irradiated through a positive film placed on the photosensitive layer to impart the hydrophilic radically polymerizable compound to the non-image areas. A method for making a lithographic printing plate, which is then developed with a cleaning solution containing mainly water.