JPH06348014A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To produce a plangraphic printing plate not requiring dampening water, having satisfactory image reproducibility and printing resistance and not generating waste. CONSTITUTION:This photosensitive compsn. contains a high molecular compd. contg. at least one group selected among sulfonic acid, phosphonic acid and a quat. N atom or a quat. P atom, an alkylene oxide polymer and a photosensitivity imparting agent or contains a high molecular compd. contg. at least one group selected among a phenolic hydroxyl group, carboxylic acid, sulfonic acid, phosphonic acid and a quat. N atom or a quat. P atom, water-soluble cellulose resin and a photosensitivity imparting agent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive composition, and more particularly to a lithographic printing plate excellent in ink receptivity to printing ink in image areas and hydrophilicity in fountain solution in non-image areas.

[0002]

2. Description of the Related Art Conventionally, as a photosensitive lithographic printing plate in which a hydrophilic photosensitive film before exposure changes to lipophilicity by exposure, for example, as a system comprising novolac resin, polyethylene oxide and a photosensitizer, Japanese Patent Publication No. 42-131. No. is disclosed. Similarly, JP-A-48-33905 discloses a system comprising a water-soluble olefin oxide polymer, a polycarboxylic acid salt and a photosensitizer.

However, in these prior arts, the contact angle of the plate surface to water has a small difference between the exposed portion and the unexposed portion,
Therefore, it is not possible to satisfy both the fountain solution affinity in the unexposed area and the printing ink affinity in the exposed area. Therefore, there is a problem in printability, and further improvement has been desired.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lithographic printing plate which is excellent in printing ink inking in the image area and hydrophilic in the fountain solution in the non-image area and has good printability. is there.

[0005]

The above problems have been solved by the present invention described below. That is, (1) a polymer compound containing at least one group selected from a sulfonic acid, a phosphonic acid and a cationic quaternary nitrogen atom or a quaternary phosphorus atom, a water-soluble olefin oxide polymer and a photosensitizer. A photosensitive composition comprising:

(2) Polymer compound containing at least one group selected from phenolic hydroxyl group, carboxylic acid, sulfonic acid, phosphonic acid and cationic quaternary nitrogen atom or quaternary phosphorus atom, and water-soluble cellulose resin And a photosensitizing agent. Hereinafter, the present invention will be described in detail.

The cationic polymer compound containing a quaternary nitrogen atom or a quaternary phosphorus atom used in the present invention is described in JP-B-2-47738, column 3, line 33 to column 13 and column 14. Mention may be made of the latex polymers disclosed in line 31.

Further, a sulfonic acid group used in the present invention,
The anionic polymer compound having at least one group selected from a carboxylic acid group and a phosphonic acid group has an acrylic group or a methacrylic group as a monomer unit, and has a carboxylic acid group, a sulfonic acid group, and a phosphonic acid group. A latex polymer is used, and specific examples of such a monomer unit include the compounds shown below.

[0009]

[Chemical 1]

[0010]

[Chemical 2]

The latex polymer can be synthesized by copolymerizing the above-mentioned monomer and a non-anionic monomer. Examples of the non-anionic monomer used include acrylic acid, methacrylic acid ester, styrene, and the like.
Examples thereof include alkylene, ether, vinyl acetate, acrylonitrile, etc., which are preferably crosslinked with a monomer having two or more functional groups such as divinylbenzene and dimethacrylate. Such non-anionic monomers are included in the anionic latex polymer of the present invention in an amount of 5 to 95%.
% By weight, and the monomer such as divinylbenzene methacrylate is preferably contained in the latex polymer in an amount of 0.1 to 1
Contains 0% by weight.

The latex polymer described above is disclosed, for example, in JP-A-59
-6203, 59-53505, 61-36747, 62-102240 and the like can be synthesized according to the emulsion polymerization method.

The polymer compound which is not a latex can be obtained by a conventionally known radical polymerization method without using the above-mentioned monomer having two or more functional groups. These latices are contained in the photoreceptor composition in an amount of 5 to 95% by weight.

Next, the water-soluble olefin oxide polymer according to the present invention preferably has an average molecular weight of about 100,000 to 10
It is in the range of, 000,000, and is usually selected from solid water-soluble resinous alkylene oxide (preferably ethylene oxide) polymers. The alkylene oxide polymer in the present invention includes not only a polymer having a simple repeating unit — ((CH ₂ CH ₂ ) _n O) — but also a copolymer of different olefin oxides. For the latter,
Examples thereof include copolymers of ethylene oxide and propylene oxide, butylene oxide, and the like.

The amount of these olefin oxide polymers used may be 5 to 95% by weight in the photosensitive composition.

Next, as the photosensitizing component in the present invention, it reacts with a polymer compound having a sulfonic acid, a phosphonic acid quaternary nitrogen atom or phosphorus atom, a phenolic hydroxyl group or a carboxylic acid group when exposed to light energy. Then, it has a function of so-called "photo-curing", or the photosensitizing component itself is polymerized and cured. (This term is also commonly used in the industry).

Suitable photosensitizing components include diazo compounds such as a condensation product of a diphenylamine diazonium salt and formaldehyde, hexavalent chromium compounds such as ammonium dichromate and potassium dichromate, and alkyl halides such as iodoform and bromoform. , And unsaturated monomers having two or more addition-polymerizable double bonds (eg, methylenebisacrylamide, ethylenebisacrylamide, methylenebismethacrylamide, triethyleneglycol diacrylate, triacrylicformal, diallylphthalate, etc.) and Along with this, photopolymerization initiators (for example, benzophenone, benzoin methyl ether) [see British Patents 1,154,872 and 1,148,328] and the like, which are generally well known, can be mentioned.

These compounds are contained in the photosensitive composition in an amount of 0.5.
May be used in the range of up to 20% by weight.

As the polymer compound having a phenolic hydroxyl group used in the present invention, a novolac resin, a resole resin, a vinyl polymer having a phenolic hydroxyl group,
Examples thereof include condensation resins of polyhydric phenols and aldehydes or ketones described in JP-A-55-57841.

Examples of the novolac resin and the resol resin used in the present invention include phenol / formaldehyde resin, cresol / formaldehyde resin, JP-A-55.
-Cresol-formaldehyde copolycondensate resin as described in JP-A-57841, JP-A-55-12755
P-substituted phenol and phenol, or cresol and formaldehyde copolycondensate resin as described in No. 3 can be used.

The molecular weight (polystyrene standard) of the novolac resin and the resol resin is preferably a number average molecular weight M.
n is 3.00 × 10 ^{2 to} 7.50 × 10 ³ , weight average molecular weight Mw is 1.00
× 10 ^{3 to} 3.00 × 10 ⁴ , more preferably Mn of 5.00 × 10 ² to
It is 4.00 × 10 ³ , and Mw is 3.00 × 10 ^{3 to} 2.00 × 10 ⁴ .

The above novolac resin and resol resin may be used alone or in combination of two or more kinds. The ratio of the novolak resin in the photosensitive composition of the present invention is 5 to 95% by weight.

Further, the vinyl polymer having a phenolic hydroxyl group used in the present invention is a polymer having a unit having the phenolic hydroxyl group in its molecular structure,
Polymers containing at least one structural unit represented by the following general formulas [I] to [V] are preferred.

[0024]

[Chemical 3]

R _{1 to} R ₄ in the formula represent a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and preferably a hydrogen atom. A represents an alkylene group which may have a substituent linked to a nitrogen atom, an oxygen atom or an aromatic carbon atom, m represents an integer of 0 to 10, and B represents a phenylene group which may have a substituent. Alternatively, it represents a naphthylene group which may have a substituent.

The polymer used in the photosensitive composition of the present invention preferably has a copolymer type structure, and is used in combination with the structural units represented by the above general formulas [I] to [V]. You can As the monomer unit, for example, ethylene, propylene, isobutylene, butadiene, isoprene and other ethylenically unsaturated olefins, for example, styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene and other styrenes, for example, acrylic. Acids, acrylic acids such as methacrylic acid, for example, itaconic acid, maleic acid, unsaturated aliphatic dicarboxylic acids such as maleic anhydride, for example, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylic acid Α-Methylene aliphatic monocarboxylic acid esters such as dodecyl, 2-chloroethyl acrylate, phenyl acrylate, α-methyl chloroacrylate, methyl methacrylate, ethyl methacrylate, ethyl ethacrylate,
For example, nitriles such as acrylonitrile and methacrylonitrol, amides such as acrylamide, and anilides such as acrylanilide, p-chloroacrylanilide, m-nitroacrylanilide, and m-methoxyacrylanilide, such as vinyl acetate and propion. Vinylate,
Vinyl esters such as vinyl benzoate and vinyl butyrate,
For example, methyl vinyl ether, ethyl vinyl ether,
Isobutyl vinyl ether, vinyl ethers such as β-chloroethyl vinyl ether, vinyl chloride, vinylidene chloride, vinylidene cyanide, for example, 1-methyl-1
Ethylene derivatives such as -methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxycarbonylethylene, 1-methyl-1-nitroethylene, such as N-vinylpyrrole, N-vinylcarbazole ,
There are vinyl monomers such as N-vinyl compounds such as N-vinylindole, N-vinylpyrrolidene, and N-vinylpyrrolidone. These vinyl-based monomers have a structure in which unsaturated double bonds are cleaved and are present in the polymer compound.

[0027]

EXAMPLES The present invention will be further described below with reference to examples.

On the surface of degreased AL having a thickness of 0.24 mm, the following resin mixture was applied so that the film thickness after drying would be 2.5 μm.
Heat treatment was performed at 0 ° C. for 20 minutes.

The compounds used in the examples are as follows.

Polymer compound (1)

[0031]

[Chemical 4]

1-3 Phenolic resin (Molecular weight: about 1500) 1-4 p-Hydroxypolystyrene (Molecular weight: about 20,000) 1-5 Styrene-maleic acid copolymer (Molecular weight: about 2)
High molecular compound (2) 2-1 Ethylene oxide polymer (molecular weight approx. 100-150
2-2 Carboxymethyl cellulose (Molecular weight approx. 100
2-3) Methyl cellulose (Molecular weight: approx. 1 million) 2-4 Hydroxymethyl cellulose (Molecular weight: approx. 100)
10,000) 2-5 Hydroxypropylmethylcellulose (Molecular weight: about 1,000,000) 2-6 Ethylcellulose (Molecular weight: about 1,000,000) Resin mixture composition Polymer compound 1 3.5g Polymer compound 2 4.5g Dimethylformamide 100g Methyl alcohol 100g Diphenylamine diazonium salt The coating layer was coated with a 3% aqueous solution of formaldehyde condensate to a film thickness of 8 μm, and dried at 80 ° C. for 2 minutes. Overlaid with a negative mesh on the plate created in this way, Idol Fin 2000
3 with 2kW metal halide lamp manufactured by Iwasaki Electric Co., Ltd.
It was exposed for 0 seconds. Table 1 below shows the measurement results of the contact angle of the exposed portion and the unexposed portion with water, and the results of printing with a coating offset printing machine.

However, the contact angles of exposed / unexposed areas with water in the table are large in exposed areas and small in unexposed areas, and the larger the difference, the better the printability as a printing plate.

The printability is (1) the image part of the printing ink.
Meatability to (exposed part). (2) Non-image area of dampening water (unexposed area)
Wettability. (3) When the supply of dampening water to the printing equipment is stopped and the non-image area is once soiled with printing ink, the dampening water wet recovery property of the non-image area when dampening water is supplied again The following three grades were evaluated for the three performances.

◯: All have no problems Δ: Any one item has problems ×: All three items have problems

[0036]

[Table 1]

As is apparent from the table, according to the present invention, the contact angle of the plate surface with respect to water has a large difference between the exposed portion and the unexposed portion, and thus it has excellent printability.

The printing durability of the printing plate produced by the method of the present invention was comparable to that of other printing plates.

[0039]

According to the present invention, it is possible to obtain a lithographic printing plate which does not require a fountain solution and which has good image reproducibility, has a short printing time, and has high printing durability. Furthermore, according to the present invention, a printing plate that does not pollute the environment because no waste is generated can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03F 7/028

Claims (2)

[Claims] 1. A polymer compound containing at least one group selected from a sulfonic acid, a phosphonic acid and a cationic quaternary nitrogen atom or a quaternary phosphorus atom, a water-soluble olefin oxide polymer and a photosensitizer. A photosensitive composition comprising: 2. A polymer compound containing at least one group selected from a phenolic hydroxyl group, a carboxylic acid, a sulfonic acid, a phosphonic acid and a cationic quaternary nitrogen atom or quaternary phosphorus atom, a water-soluble cellulose resin, and A photosensitive composition comprising a photosensitizer.