JPH075686A - Photosensitive composition - Google Patents

Abstract

PURPOSE:To provide such a compsn. that gives high physical durability when the compsn. is used to form a photosensitive layer and that gives high printing durability when the compsn. is used for a photosensitive printing plate by incorporating two kinds of polymer compds. having specified structures and a photopolymn. initiator. CONSTITUTION:This compsn. contains polymer compds. having a structure expressed by formula I and a structure expressed by formula II in the molecule, and a photopolymn. initiator. In formulae I, II, R<1>-R<4> are hydrogen atoms or methyl groups, R<5> and R<6> are hydrogen atoms, methyl groups, ethyl groups, phenyl groups, and X is -O-, etc. To introduce the structures expressed by formulae I, II into molecules to form the polymer compd., it is preferable to perform radical polymn. of monomers having a structure expressed by formula III with other copolymerizable monomers as required. In formula III, R<1>-R<6> and X are same as in formulae I, II.

Description

Detailed Description of the Invention

[0001]

[0002]

BACKGROUND OF THE INVENTION Various photosensitive compositions have heretofore been proposed, which constitute various photosensitive lithographic printing plates (hereinafter also referred to as PS plates).

A photosensitive printing plate is generally manufactured by coating a photosensitive composition on a support such as an aluminum plate. When the photosensitive printing plate is, for example, a negative type, it is usually irradiated with an actinic ray such as an ultraviolet ray through a negative image, and the light-irradiated portion is polymerized or cross-linked to make this portion insoluble in a developing solution. After that, after development, the non-irradiated areas are eluted in the developing solution, and the respective areas are image areas that repel water and receive the oil-based ink, and non-image areas that receive water and repel the oil-based ink. Is commonly used.

As the photosensitive composition in this case,
In particular, negative PS plates can be generally classified into a case where a diazonium resin is used as a photoconductor and a case where a compound having an ethylenically unsaturated bond and a photopolymerization initiator are mixed and used. The latter photosensitive composition is called a photopolymerization composition, and is generally a monomer (or oligomer) having an ethylenically unsaturated bond, a photopolymerization initiator, and a polymer binder (hereinafter simply referred to as a binder). Consists of. As a general polymer compound as a binder for the photopolymerization composition, there can be mentioned polymers such as polyacrylic, polyvinyl formal, polyvinyl butyral, polyurethane and polyester.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention When a photopolymerization initiator is contained to prepare a photosensitive composition utilizing a photopolymerization reaction, the photosensitive composition contains an ethylenic compound capable of being polymerized in a side chain. A technique for obtaining a photosensitive composition having high sensitivity by containing a polymer compound having a saturated bond is known (Japanese Patent Laid-Open No. 1-219736).

However, in the case of forming a photosensitive lithographic printing plate using a high-sensitivity photosensitive composition, not only the sensitivity is required but also the printing durability is large and the resistance to printing a large number of sheets is possible. Required to have.
Particularly, with the spread of offset rotary presses in recent years, the demand for printing durability has further increased. Therefore, it is desired to develop a photosensitive composition which is highly sensitive and has a large physical resistance when a photosensitive layer is formed, and thus can obtain a plate having a large printing durability even when applied to a printing plate. It is rare.

The present invention has been made in view of the above circumstances and provides a printing plate having a large physical resistance when a photosensitive layer is formed, and thus having a large printing durability even when used as a photosensitive printing plate. The object is to provide a photosensitive composition that can be obtained.

[0008]

[Means and Actions for Solving Problems] The object of the present invention is represented by a structure represented by the general formula (1) and a general formula (2) described in claim 1 in the molecule. It is achieved by a photosensitive composition comprising a polymer compound having a structure having the following structure and a photopolymerization initiator (hereinafter also appropriately referred to as "the photosensitive composition of the present invention"). Less than,
Further, the present invention will be described in detail.

(Polymer Compound According to the Present Invention) The photosensitive composition of the present invention comprises a polymer compound having a structure represented by the general formula (1) and a structure represented by the general formula (2) in the molecule. (In the present specification, this is also referred to as a polymer compound of the present invention).

To form the polymeric compound of the present invention,
Although various means for introducing the structure represented by the general formula (1) and the structure represented by the general formula (2) into the molecule are conceivable, for example, preferably, in order to introduce these structures into the molecule, The monomer having the structure represented by the general formula (3) may be radically polymerized with another copolymerizable monomer, if necessary.

[Chemical 3]

However, R ^{1 to} R ⁶ and X are represented by the general formula (1),
It is the same as in (2).

Typical monomers having a structure represented by the general formula (3) are allyl acrylate, allyl methacrylate, N-allyl acrylamide, N-allyl methacrylamide, N-allyl-N-methyl acrylamide, N-allyl-N-methylmethacrylamide, N-allyl-N-ethylacrylamide, N
-Allyl-N-ethylmethacrylamide, N-allyl-
Examples thereof include N-phenylacrylamide and N-allyl-N-phenylmethacrylamide.

The polymer compound of the present invention can be obtained by polymerizing the monomer represented by the above general formula (3) alone, but it may be combined with other copolymerizable monomer if necessary. Absent. Preferred other copolymerizable monomers are classified into the following four types.

(1) Carboxylic acid and acid anhydride monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, itaconic anhydride and maleic anhydride.

(2) Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, Acrylic ester, methacrylic acid ester such as pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate Kind.

(3) Cyano group-containing monomers such as acrylonitrile, methacrylonitrile, cyanophenyl acrylate, cyanophenyl methacrylate, cyanomethyl acrylate, cyanomethyl methacrylate, cyanoethyl acrylate and cyanoethyl methacrylate.

(4) 2-hydroxyethyl (meth) acrylate, N- (4-hydroxyphenyl) (meth) acrylamide, N-methylol (meth) acrylamide, 4-hydroxyphenyl (meth) acrylate, p
-OH group containing monomers such as hydroxystyrene.

Other monomers may be copolymerized with other monomers, if desired. In addition to the above monomer groups (1) to (4), N-vinylpyrrolidone, glycidyl (meth) acrylate, fluorinated alkyl (meth) acrylate and the like can be mentioned.

The above monomers can be easily polymerized by heating in the presence of a commonly used radical polymerization initiator to obtain a target polymer compound. Hereinafter, synthesis examples of the polymer compound of the present invention will be described.

(Synthesis Example-1) 12.9 g of methacrylic acid,
107.1 g of allyl methacrylate and 1.23 g of α, α′-azobisisobutyronitrile were dissolved in 300 ml of a mixed solution of methanol / acetone (1: 1), and the mixture was distilled under a nitrogen stream for 12 hours, and then the reaction solution was mixed with 3 104.4 g of polymer compound A was added dropwise to liter of water, and the solid substance was collected by filtration and dried.
Obtained.

(Synthesis Example-2) The monomer composition of Synthesis Example-1 was prepared by using 7.2 g of acrylic acid and N-allylmethacrylamide 1
The same operation was performed except that the amount was changed to 12.5 g to obtain 101.7 g of polymer compound B.

(Synthesis Example-3) The monomer composition of Synthesis Example-1 was 15.0 g of methyl methacrylate and 1 methacrylic acid.
138.3 g of polymer compound C was obtained by performing the same operation except that the amount of 2.9 g and N-allyl-N-phenylmethacrylamide 140.7 g were changed.

The molecular weight of the polymer compound can be measured by GPC using polystyrene as a standard. This G
The number average molecular weight Mn and the weight average molecular weight Mw are calculated by PC (gel permeation chromatography method) by Morio Tsugeo, Tatsuya Miyabayashi, and Masayuki Tanaka "Journal of the Chemical Society of Japan".
The method described on pages 800 to 805 (1972) can be used to level the peaks in the oligomer region (connect the peak and valley centerlines).

The photosensitive composition of the present invention can be used in combination with various polymer compounds in addition to the polymer compound of the present invention. Examples of the polymer compound that can be preferably used in combination with the polymer compound according to the present invention include polyamide, polyether, polyester, polycarbonate, polystyrene, polyurethane, polyvinyl chloride and copolymers thereof, polyvinyl butyral resin, polyvinyl formal resin, and shellac. , Epoxy resin, phenol resin, acrylic resin and the like.

The photosensitive composition of the present invention contains a photopolymerization initiator. The photopolymerization initiator that can be used in the present invention will be described below. In the present invention, as the photopolymerization initiator, various known ones can be arbitrarily used, but particularly preferable ones are thioxanthone-based, anthraquinone-based, benzophenone-based, benzoin-based, benzoic acid ester-based, and tolhalomethyl-based. It is a polymerization initiator. Specifically, the following compounds can be preferably used.

[Chemical 4]

[Chemical 5]

[Chemical 6]

[Chemical 7]

In the present invention, a polymerization inhibitor such as hydroquinone, together with the above-mentioned various photopolymerization initiators,
p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-butylphenol), 2,2'-methylenebis (4 -Methyl-6-t-butylphenol), 2-mercaptobenzimidazole and the like may be used in combination.

(Photopolymerizable Monomer, etc.) Next, it is one preferable embodiment that the photosensitive composition of the present invention contains a photopolymerizable monomer. In the photosensitive composition of the present invention, The preferable photopolymerizable monomer and / or oligomer contained are as follows.

Specifically, such a monomer is, as an oligomer, specifically, a monofunctional acrylate or methacrylate such as polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, or phenoxyethyl (meth) acrylate;

Polyethylene glycol di (meth) acrylate, polypropylene di (meth) acrylate, trimethylolethane tri (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythryl tri (meth) acrylate, pentaerythritol tetra ( Add ethylene oxide or propylene oxide to polyhydric alcohols such as (meth) acrylate, dipentaerythryl hexa (meth) acrylate, hexanediol di (meth) acrylate, tri (acryloyloxyethyl) isocyanurate, glycerin and trimethylolethane. (Meth) acrylate after the reaction, JP-B-48-41708, JP-B-50-6
No. 034, JP-A-51-37193, urethane acrylates as described in each specification, JP-A-48-
No. 64183, Japanese Patent Publication No. 49-43191, Japanese Patent Publication No. 52
Examples thereof include polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with a (meth) acrylic acid described in JP-A-30490.

Further, in detail, the Japan Adhesive Association Vol. Two
0, No. The polymerizable compounds introduced as photocurable monomers and oligomers on pages 7,300 to 308 can also be used.

(Other Components) In addition to the components described above, dyes, pigments, coatability improvers, plasticizers and the like can be added to the photosensitive composition of the present invention, if necessary.

Examples of the above dyes include Victoria Pure Blue BOH (Hodogaya Chemical Co., Ltd.), Oil Blue # 603 (Orient Chemical Co., Ltd.), Patent Pure Blue (Sumitomo Mikuni Chemical Co., Ltd.), Crystal Violet, Brilliant Green, Ethyl. Violet, Methyl Green, Erythrosin B, Basic Fuchsin, Malachite Green, Oil Red, m-Cresol Purple,
Triphenylmethane-based, diphenylmethane-based, oxazine-based, xanthene-based, iminonaphthoquinone-based, azomethine-based or anthraquinone-based represented by rhodamine B, auramine, 4-p-diethylaminophenyliminonaphthoquinone, and cyano-p-diethylaminophenylacetanilide. A dye can be mentioned.

When the dye is added, it is usually contained in the photosensitive composition in an amount of preferably about 0.5 to about 10% by weight, more preferably about 1 to 5% by weight.

As the coatability improver, alkyl ethers (eg ethyl cellulose, methyl cellulose),
Examples thereof include fluorine-based surfactants and nonionic surfactants [for example, BLURONIC L-64 (manufactured by Asahi Denka Co., Ltd.)]. Examples of the plasticizer for imparting flexibility and abrasion resistance to the coating film include butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate,
Dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate,
Mention may be made of acrylic acid or methacrylic acid oligomers. Examples of the oil sensitizer for improving the oil sensitivity of the image area include a half-esterified product of an alcohol of a styrene-maleic anhydride copolymer described in JP-A-55-527. Examples of the stabilizer include polyacrylic acid, tartaric acid, phosphoric acid, phosphorous acid, organic acids (acrylic acid, methacrylic acid, citric acid, oxalic acid, benzenesulfonic acid, naphthalenesulfonic acid, 4-methoxy-2-hydroxy). -Benzophenone-5-sulfonic acid, etc.) and the like. The amount of these additives added varies depending on the intended use and purpose, but it is generally preferable to use about 0.01 to 30 wt% of the total solid content.

(Application to Photosensitive Planographic Printing Plate) The photosensitive composition of the present invention can be coated on the surface of a support and dried to obtain a photosensitive lithographic printing plate.

As the coating solvent, cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve and ethyl cellosolve acetate, dimethyldiglycol, dimethylformamide, dimethylsulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, methyl ethyl ketone, 4-hydroxybutanone. Etc. can be mentioned. These solvents may be used alone or in admixture of two or more.

As the coating method, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating and curtain coating can be used. The coating amount is 0.2 to 10 as solid content.
g / m ² is preferred.

An aluminum plate is preferably used for the support of the photosensitive lithographic printing plate. Graining treatment is carried out by electrolytic graining in nitric acid or an electrolytic solution containing nitric acid as a main component, or hydrochloric acid or an electrolytic solution containing hydrochloric acid as a main component, and preferably further anodizing treatment and sealing if necessary. It is desirable to use a surface-treated material such as a hole-treated material.

The electrolytic surface roughening is preferably 0.1 to 1.0.
Mol / liter, more preferably 0.2 to 0.6 mol / l
An aluminum plate is immersed in a bath containing 1 liter of nitric acid or hydrochloric acid, preferably at a temperature of 20 to 50 ° C, more preferably 25 to 40 ° C, and a preferable current density of 20 to 2
It is preferable to perform electrolytic etching at 00 A / dm ² for about 10 seconds to 3 minutes. After this graining treatment, if necessary, desmut treatment is performed with an aqueous solution of alkali or acid to neutralize and washing with water.

The anodic oxidation treatment is carried out by electrolysis using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid and the like as an electrolytic solution and using an aluminum plate as an anode. preferable. The amount of the anodized film formed is generally preferably 1 to 50 mg / dm ² , and more preferably 10 to 40 mg / dm ² . Here, the amount of anodized film is, for example, a solution of aluminum chromic acid phosphoric acid solution (35 ml of 85% phosphoric acid aqueous solution and 20 g of chromium (IV) oxide dissolved in 1 liter of water)
It can be determined by immersing in an oxide film to dissolve the oxide film and measuring the weight change of the plate before and after the film is dissolved.

The sealing treatment includes boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment and the like. In addition to this, the aluminum support may be subjected to a subbing treatment with a water-soluble polymer compound or an aqueous solution of a metal salt such as fluorinated zirconic acid.

The photosensitive lithographic printing plate thus obtained can be used by a known method. Typically, a negative type film is brought into close contact with the photosensitive printing plate, exposed by an ultrahigh pressure mercury lamp, a metal halide lamp or the like, and developed using various known developing solutions to obtain a printing plate. The lithographic printing plate thus produced can be used in a sheet-fed, off-wheel printing machine.

That is, by exposing through a transparent original image having a line image, a halftone image and the like, and then developing with an aqueous developer, a negative relief image is obtained with respect to the original image. Suitable light sources for exposure include carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes and the like.

Any known developer may be used for the development treatment of the photosensitive lithographic printing plate. For example, an organic solvent represented by benzyl alcohol or ethylene glycol monophenyl ether, an alkali metal silicate, or the like. Alkaline agents such as organic amine compounds, and those containing water as the main component, or without organic solvent,
It is preferable to use the above-mentioned alkaline agent, an anionic surfactant typified by higher alcohol sulfuric acid ester salts and alkylaryl sulfonates, and one containing an organic carboxylic acid as a main component.

The photosensitive lithographic printing plate is exposed imagewise and then exposed to the above-mentioned developing solution or rubbed, and after 10 to 60 seconds at about 10 to 40 ° C., the photosensitive layer is exposed. The photosensitive composition in the non-exposed area is completely removed without adversely affecting the area, and thus the photosensitive composition can be used in this manner.

[0046]

EXAMPLES The present invention will now be described in more detail with reference to examples, but it goes without saying that the present invention is not limited to these examples.

Examples 1, 2, 3 and Comparative Example 1 An aluminum plate was degreased with a 10 wt% sodium hydroxide aqueous solution and this was degreased in a 1.8% hydrochloric acid bath at 25 ° C. and 30 A /.
Electrolytic etching was performed under conditions of current density of dm ² for 30 seconds, washed with water, and then anodized for 30 seconds in a 30% phosphoric acid bath at 30 ° C. and 6.5 A / dm ² . Next, a 1 wt% sodium metasilicate aqueous solution was used for sealing treatment at 85 ° C. for 30 seconds, followed by washing with water and drying to obtain an aluminum plate as a lithographic printing plate support.

A photosensitive composition liquid having a composition as shown in Table 1 was applied to the aluminum plate so that the film weight after drying was 1.7 g / m ² to obtain a photosensitive lithographic printing plate sample. .

[Table 1] (Part 1)

[Table 1] (Part 2)

[Chemical 8]

[Chemical 9]

The samples of the respective examples obtained as described above were
Place a negative transparent original image and a step wedge (increased by a density difference of 0.15), and use a 2kw metal halide lamp for 6
After exposure for 30 seconds from a distance of 0 cm, the product was exposed to "SDN-21 developer" (manufactured by Konica, diluted 1: 3) at 25 ° C and 40
It was soaked for a second and then lightly rubbed with absorbent cotton to develop.
The lithographic printing plate sample after development was printed by a Heidelberg GTO printing machine, and evaluated by the number of printed sheets at the time when scratches were observed in the image portion of the plate. The results are shown in Table 2.

It can be seen from Table 2 that the examples of the present invention have improved abrasion resistance (printing durability) as compared with the comparative examples.

[Table 2]

[0051]

As described above, the photosensitive composition of the present invention has an effect that when a photosensitive layer is formed thereby, it is possible to obtain one having excellent physical resistance (abrasion resistance). It can be preferably used to form a photosensitive lithographic printing plate having excellent strength.

Claims (1)

[Claims] 1. A constitution comprising a polymer compound having a structure represented by the following general formula (1) and a structure represented by the following general formula (2) in the molecule and a photopolymerization initiator. Photosensitive composition. [Chemical 2]