JPH0468357A - photosensitive composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photosensitive composition. The photosensitive composition of the present invention can be used, for example, to constitute a photosensitive layer of a lithographic printing plate.

[Background of the invention and problems to be solved]

Various photosensitive compositions have been proposed in the past, and various photosensitive lithographic printing plates (hereinafter sometimes referred to as PS plates) are constructed using these compositions.

Photosensitive printing plates are generally manufactured by coating a photosensitive composition on a support such as an aluminum plate. The photosensitive printing plate is
For example, in the case of a negative type, it is usually irradiated with active light such as ultraviolet rays through a negative image, etc., and the irradiated areas are polymerized or crosslinked to make these areas insoluble in the developer, and then developed. The non-irradiated area is eluted into the developer,
Generally, each portion is used as an image area that repels water and receives oil-based ink, and a non-image area that receives water and repels oil-based ink.

As a photosensitive composition constituting the photosensitive layer of a negative-working PS plate, a mixture of a diazo resin and a polymer functioning as a binder is known.

However, when the above-mentioned photosensitive composition is used to constitute a photosensitive layer of a photosensitive lithographic printing plate, it has the following disadvantages: - Ink receptivity is low for boat fishing, and sensitivity is insufficient. has.

On the other hand, photopolymerizable photosensitive compositions are known as photosensitive compositions that have good ink receptivity and provide a highly sensitive photosensitive layer. A typical composition of a photopolymerizable photosensitive composition is one consisting of a binder resin, a photopolymerizable monomer, and a photopolymerization initiator.

In particular, when a crosslinkable polymer is used as the binder resin,
It is known to provide a printing plate with excellent sensitivity and abrasion resistance (Japanese Patent Publication No. 17874/1983).

However, these crosslinkable polymers are difficult to synthesize,
This had the disadvantage that developability deteriorated when the printing plate was stored for a long period of time.

[Purpose of the invention]

The present invention solves the above-mentioned problems of the conventional technology, and when used in a photosensitive lithographic printing plate, it has good ink receptivity, high sensitivity, excellent stiffness resistance, and furthermore, it has low developability during storage. The object of the present invention is to provide an excellent photosensitive composition that can provide a photosensitive lithographic printing plate free of oxidation.

[Failure to solve the problem]

The above object of the present invention has been achieved by a photosensitive composition containing a polymer compound having a structure represented by the following general formula (1) as a repeating unit in the molecule.

1→-CH-CH-÷- c=o c=.

General formula (1) However, in general formula (I), R' represents a substituent having an ethylenically unsaturated bond, R2 represents a hydrogen atom, an alkyl group, or an aryl group, and R3 represents a hydrogen atom, an alkyl group, Represents a substituent containing an aryl group or an alkenyl group.

The present invention will be explained in more detail below.

(Polymer compound according to the present invention) First, general formula (1) contained in the photosensitive composition of the present invention
A polymer compound (hereinafter also referred to as "polymer compound J according to the present invention") containing the structure represented by the following as a repeating unit will be described.

The polymer compound according to the present invention has an ethylenically unsaturated bond in its side chain that can be polymerized by irradiation with light in the presence of a photopolymerization initiator, and specifically, it has the general formula ( It contains the structure of I) as a repeating unit.

In the above general formula (1), R1 is a substituent containing an ethylenically unsaturated bond, and specifically, preferable ones include:
Examples include a vinyl group, an allyl group, a cinnacil group, an acryloyl group, a methacryloyl group, and a p-styryl group. Particularly preferred are allyl group and p-styryl group.

R2 is a hydrogen atom, an alkyl group, or an aryl group, with a hydrogen atom being most preferred.

Examples of R3 include a hydrogen atom, an alkyl group, an aryl group, and an alkenyl group. Specifically preferred are a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a phenyl group, a Hensyl group, and the like.

A preferred composition of the polymer compound according to the present invention is one containing 5 to 80 mol%, more preferably 10 to 60 mol%, of the structural unit represented by general formula (1).

Moreover, the molecular weight is preferably 600 to 100,000,
More preferably, it is about 1,000 to 80,000.

Next, an example of a method for synthesizing a polymer compound according to the present invention will be described.

Synthesis to polymer compound: DM in a 4 flask equipped with a stirrer and a thermometer.
Add 200 g of F (dimethylformamide) and 61.6 g of maleic anhydride-isobutylene copolymer (copolymerization ratio 1:1, trade name Isohan-10, manufactured by Kuraray ■),
Completely dissolve at 80°C. After that, as a first reaction, 48.2 g of p-aminostyrene and 1.0 g of hydroquinone were mixed.
After adding 0g, stir and react at 80-85°C for 9 hours. Then, 15.6 g of n-butyl alcohol is added, and the mixture is stirred again at a reaction temperature of 80 to 85°C for 9 hours. After the reaction was completed, the reaction solution was cooled to room temperature, poured into a weakly acidic aqueous solution of hydrochloric acid (No. 21), and the resulting precipitate was filtered and dried to obtain a polymer compound A.

In this specification, the molecular weight of a polymer substance is measured by GPC.
Assume that polystyrene is used as the standard. This GP
Calculation of number average molecular weight Mn and weight average molecular weight Mw by C (gel permeation chromatography method) is as follows:
Written by Morio Tsuge, Tatsuya Miyabayashi, and Masayuki Tanaka, “Journal of the Chemical Society of Japan” 80
This can be done by leveling the peaks of the oligomer region (connecting the center lines of the peaks and valleys) by the method described on pages 0 to 805 (1972).

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

Preferably, the copolymers shown in (1) to (12) below, which are alkali-soluble and swellable polymer compounds, are mentioned. 5, ゝ・) The following margin J"J
-hydroxyphenyl)acrylamide or N-(4
-hydroxyphenyl) methacrylamide, o +-,
m-, p-hydroxystyrene, o-m-, p-hydroxyphenyl-acrylate or -methacrylate.

(2) Seven polymers having aliphatic hydroxyl groups, such as 2-hydroxyethyl acrylate or 22-hydroxyethyl methacrylate.

(3) α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride.

(4) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, acrylic acid-
(Substituted) alkyl acrylates such as 2-chloroethyl, 2-hydroxyethyl acrylate, glycidyl acrylate, and N-dimethylaminoethyl acrylate.

(5) Methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, butyl methacrylate, amyl methacrylate, cyclohexyl methacrylate, 2
-Hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, glycidyl methacrylate, N-
(Substituted) alkyl methacrylates such as dimethylaminoethyl methacrylate.

(6) Acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide,
Acrylamides or methacrylamides such as N-ethylacrylamide, N-hexylacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylamide, and N-ethyl-N-phenylacrylamide.

(7) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.

(8) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate.

(9) Styrenes such as styrene, α-methylstyrene, methylstyrene, and tetramethylstyrene.

(10) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.

(11) Olefins such as ethylene, propylene, isobutylene, phtadiene, and isoprene.

(12) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylatel, etc.

Furthermore, a monomer that can be copolymerized with the above-mentioned polymer may be copolymerized. In addition, the copolymerization pair obtained by the copolymerization of the above-mentioned heptamers, for example, glycidyl methacrylate,
It also includes, but is not limited to, those modified with glycidyl acrylate and the like.

(Photopolymerization initiator) In a preferred embodiment, the photosensitive composition of the present invention contains a photopolymerization initiator. Photopolymerization initiators that can be used in the present invention will be described below.

In the present invention, various known photopolymerization initiators can be used, but particularly preferred are thioxanthone-based, anthraquinone-based, hensifhenone-based, hendiine-based, benzoic acid ester-based, and tolhalomethyl-based photopolymerization initiators. It is a polymerization initiator. Specifically, the following compounds can be preferably used.

+ ido CCZ3 Moreover, a diazo compound can also be used as a photopolymerization initiator. Among the diazo compounds, those preferably used are organic and inorganic acid salts of p-diazodiphenylamine derivatives, and among them, diazodiphenylamine sulfonate and diazodiphenylamine trifluorophosphate are preferred.

Furthermore, diazo resins obtained by polycondensing these diazo compounds with carbonyl compounds can also be preferably used. Among them, a polycondensate of diazodiphenylamine trifluorophosphate and formaldehyde is preferred. It is also preferable to add other aromatics during this polycondensation to form a co-condensate.

An example of the synthesis of a diazo resin preferable as a diazo compound is shown below.

14.5 g of p-diazodiphenylamine sulfate containing diazo 81 was dissolved in 40 g of concentrated sulfuric acid under water cooling. 1.05 g of paraformaldehyde was slowly added to the reaction solution. At this time, the addition was carried out so that the reaction temperature did not exceed 10°C. Thereafter, stirring was continued for 2 hours under water cooling. This reaction mixture was added dropwise to 500 m2 of ethanol under water cooling, and the resulting precipitate was filtered off.

After washing the precipitate with ethanol, the precipitate was dissolved in 100-pure water, and to this solution was added an aqueous solution in which 6.8 g of zinc chloride was dissolved. The resulting precipitate was filtered off, washed with ethanol, and dissolved in 150n+A pure water. An aqueous solution in which 8 g of ammonium hexafluorophosphate was dissolved was added to this solution, and the resulting precipitate was filtered, washed with water and ethanol, and dried at 25°C for 3 days to obtain diazo resin 1. Ta.

The photosensitive composition of the present invention contains 1 to 60 parts by weight of a photopolymerization initiator (and/or a diazo resin functioning as a photopolymerization initiator) per 100 parts by weight of a binder resin containing at least the polymer compound according to the present invention. It is preferable to contain
More preferably, the content is 3 to 40 parts by weight.

In the present invention, in addition to the various photoinitiators described above, polymerization inhibitors such as hydroquinone p-methoxyphenol, di-L-butyl-p-cresol, pyrogallol, t-butylcatechol, henzoquinone, 4.4°-
Thiobis(3-methyl-6-t-butylphenol),
2.2'methylenebis(4-methyl-6-t-butylphenol), 2-mercaptobenzimidazole, etc. may be used in combination.

(Photopolymerizable Monomer, etc.) Next, one preferable embodiment of the photosensitive composition of the present invention is that it contains a photopolymerizable monomer or the like, especially when a photopolymerization initiator is used. The photopolymerizable monomer is a binder resin 1 containing at least a polymer compound according to the present invention.
It is preferably contained in an amount of 3 to 100 parts by weight, more preferably 5 to 60 parts by weight.

Preferred photopolymerizable monomers and/or oligomers contained in the photosensitive composition of the present invention include the following.

That is, such monomers, specifically as oligomers, include polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate,
Monofunctional acrylates and methacrylates such as phenoxyethyl (meth)acrylate; polyprolene glycol di(meth)acrylate, polypropylene di(meth)acrylate, trimethylolethane tri(meth)acrylate, neobentyl glycol di(meth)acrylate, Pentaerythritol tri(meth)acrylate, Pentaerythritol tetra(meth)acrylate,
dipentaerythryl hexa(meth)acrylate,
Hexanediol di(meth)acrylate, tri(acryloyloxyethyl)isocyanurate, polyhydric alcohol such as glycerin or trimethylolethane added with ethylene oxide or propylene oxide and then converted into (meth)acrylate, 1977- 41708
No., Special Publication No. 50-6034, Japanese Patent Publication No. 51-37193
Urethane acrylates as described in each specification, JP-A No. 48-64183, JP-B No. 414319
Examples include polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth)acrylic acid, which are described in the specifications of No. 1 and Japanese Patent Publication No. 52-30490. Furthermore, in detail, the Japan Adhesive Association νo1.2
0. Polymerizable compounds introduced as photocurable monomers and oligomers in No. 7, pp. 300-308 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 dye include Victoria Pure Blue B.
OH (manufactured by Odugaya Chemical Co., Ltd.), Oil Blue #603 (manufactured by Orient Chemical Co., Ltd.), Patent Pure Blue (manufactured by Susumu Kingdom Chemical Co., Ltd.), Crystal Violet, Brilliant Green, Ethyl Violet, Methyl Green, Erythrosin B, Basinokufuchsin, malachite green,
Oil red, m-cresol purple, Rhodamine B
Triphenylmethane-based, diphenylmethane-based, oxazine-based, xanthine-based, iminonaphthoquinone-based, azomethine-based or anthraquinone-based pigments, such as 1 auramine, 4-p-diethylaminophenylimino naphthoquinone, cyano-p-diethylaminophenyl acetanilide, etc. can be mentioned.

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

Examples of the coating property improver include alkyl ethers (eg, ethyl cellulose, methyl cellulose), fluorine-based surfactants, and nonionic surfactants (eg, Pluronic L-64 (manufactured by Asahi Denka)). Examples of plasticizers for imparting flexibility and abrasion resistance to coating films include butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, and phosphorus. Oligomers of tributyl acid, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid can be used. As a liposensitizing agent for improving the liposensitivity of the image area, there may be mentioned, for example, a half ester of a styrene-maleic anhydride copolymer with alcohol described in JP-A-55-527. As stabilizers, for example,
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-hydroxybenzophenone-5-sulfonic acid, etc.). The amount of these additives added varies depending on the object and purpose of use, but it is generally preferable to use them in an amount of about 0.01 to 30 wt% based on the total solid content.

(Application to Photosensitive Planographic Printing Plate) A photosensitive planographic printing plate can be obtained by applying the photosensitive composition of the present invention onto the surface of a support and drying it.

Examples of coating solvents include cellosolves such as methyl cellosolve, methyl cellosolve acetate, ethyl cellosolve, and ethyl cellosolve acetate, dimethyl diglycol, dimethyl formamide, dimethyl sulfoxide, dioxane, acetone, cyclohexanone, trichloroethylene, methyl ethyl ketone, 4-hydroxybutanone, and the like. be able to. These solvents may be used alone or in combination 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 preferably 0.2 to Log/bo in terms of solid content.

It is preferable to use an aluminum plate as the support for the photosensitive lithographic printing plate. The surface is grained by electrolytic roughening in nitric acid or an electrolytic solution containing nitric acid as a main component, or in hydrochloric acid or an electrolytic solution containing hydrochloric acid as a main component, preferably further anodized and sealed if necessary. It is desirable to use one that has undergone surface treatment such as hole treatment.

Electrolytic surface roughening is carried out by immersing an aluminum plate in a bath containing nitric acid or hydrochloric acid, preferably 0.1 to 1.0 mol/l, more preferably 0.2 to 0.6 mol/l. at a temperature of 20-50°C, more preferably 25-40″C, with a preferred current density of 20-20OA/drrf,
It is preferable to perform electrolytic etching for about 10 seconds to 3 minutes.

After this graining treatment, if necessary, desmut treatment is performed with an aqueous alkali or acid solution to neutralize it, and then washed with water.

The anodic oxidation treatment is preferably carried out by electrolyzing using an aluminum plate as an anode using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid, etc. as an electrolytic solution. The amount of anodic oxide film formed is
1 to 50 μ/drrr is generally appropriate and preferred, and more preferably 10 to 40 μ/dn (.Here, the amount of anodized film is determined by, for example, converting the aluminum solution into a phosphoric acid chromic acid solution (85% phosphoric acid aqueous solution 35% and chromium(IV) oxide2
0g and dissolved in 11 water)! It can be determined by dipping the plate in this water to dissolve the oxide film and measuring the change in weight of the plate before and after the film melts.

Pore sealing treatments include boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment, and the like. In addition, water-soluble polymer compounds,
Subbing treatment can also be performed using an aqueous solution of a metal salt such as fluorinated zirconate.

The photosensitive lithographic printing plate thus obtained can be used by a known method. Typically, a negative film is brought into close contact with a photosensitive printing plate, exposed to light using an ultra-high pressure mercury lamp, metal halide lamp, etc., and developed using various known developers to obtain a printing plate. The lithographic printing plate produced in this manner can be used in sheet-fed and off-wheel printing presses.

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

The developer used in the development of the photosensitive lithographic printing plate may be any known developer, but for example, organic solvents such as benzyl alcohol and ethylene glycol monophenyl ether, alkali metal silicates, and organic amines may be used. Alkaline agents such as compounds, and those containing water as a main component, or those that do not contain organic solvents, and anionic surfactants such as the above-mentioned alkaline agents, higher alcohol sulfate ester salts and alkylaryl sulfonates. ,
It is preferable to use one containing an organic carboxylic acid as a main component.

After imagewise exposure, the photosensitive lithographic printing plate can be heated to about 10°C by contacting it with the above-mentioned developer or by rubbing it.
After 10 to 60 seconds at ~40°C, the photosensitive composition in the non-exposed areas of the photosensitive layer is completely removed without adversely affecting the exposed areas, so it can be used in this manner.

〔Example〕

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

Examples 1 and 2 and Comparative Examples 1 and 2 An aluminum plate was degreased with a 10 wt% aqueous sodium hydroxide solution, and heated at 25°C at 130A in a 1.8% hydrochloric acid bath.
/drW, electrolytically etched at a current density of 30 seconds,
After washing with water, it was anodized in a 30% sulfuric acid bath at 30° C. and 5 A/d Bo for 30 seconds. Next, the plate was sealed with a 1 wt % sodium metasilicate aqueous solution at 85° C. for 130 seconds, washed with water and dried to obtain an aluminum plate as a support for a lithographic printing plate.

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

Table *Comparative polymer compounds used in Comparative Example-1 are as follows.

a:b:c:d:e=51:8:4:18:19coz
=c-CI.

Place a negative transparent original image and a step sea urchin (increased at a density difference of 0.15) on each side of the sample obtained as above in the following margins, and place a metal halide lamp on 2. After exposure for 30 seconds from a distance of 60 cm, it was immersed in rsDN-21 developer (manufactured by Konica, diluted 1:3) at 25°C for 140 seconds, and then developed by rubbing lightly with absorbent cotton.

The number of steps of the step wedge after development was as shown in Table 2.

The obtained plate was printed using a Heidelberg GTO printing machine, and the developability was evaluated based on the degree of staining of the printed paper surface.

In addition, the sample after coating was forcibly stored (temperature 55°C, humidity 2
0% RH for 15 days), exposure, development, and printing were performed in the same manner as above, and the developability after storage was evaluated.

Ink receptivity was tested by applying Konica PS version gum liquid 5GQ-3 (diluted 2 times) to a sample exposed and developed in the same manner as above, printing, and removing the gum in the image area. is,
Comparison and evaluation were made based on the number of sheets required to obtain normal inking.

Further, the film strength of the image area was evaluated by printing in the same manner using a Heidelberg GTO printing machine and based on the number of sheets printed at the time when scratches were observed in the image area of the plate.

The results are also shown in Table-2.

Margin 226 below - Table 2 shows that the examples of the present invention have better sensitivity, developability, developability after forced storage, stiffness resistance, and
It showed excellent results in terms of ink adhesion.

[Effects of the Invention] As described above, the photosensitive composition of the present invention has high sensitivity, good developability, and good developability after forced deterioration, so that there is no decrease in developability during storage. However, it is possible to obtain a photosensitive lithographic printing plate having excellent stiffness resistance and ink receptivity.

Claims (1)

[Claims] 1. A photosensitive composition containing a polymer compound having a structure represented by the following general formula (I) as a repeating unit in the molecule. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ General formula (I) However, in the general formula (I), R^1 represents a substituent having an ethylenically unsaturated bond, and R^2 represents a hydrogen atom, an alkyl group, or It represents an aryl group, and R^3 represents a substituent containing a hydrogen atom, an alkyl group, an aryl group, or an alkenyl group.