JPS63213848A - Original plate for waterless planographic printing plate - Google Patents

Abstract

PURPOSE:To improve the printing resistance of a printing plate by incorporating an acrylic acid deriv. copolymer into the photosensitive layer thereof. CONSTITUTION:The quinone diazide compd. to be used for the photosensitive layer is the ester obtd. by reaction of an ordinarily commonly used quinone diazide sulfonic acid or the deriv. thereof and a compd. (more particularly high-polymer compd.) having a hydroxyl group and the acrylic acid deriv. copolymer to be incorporated therein is a copolymer contg. >=50mol.% acrylic acid deriv. monomer having the structure expressed by the formula I. In the formula, R1 denotes a hydrogen or alkyl group of 1-10C; X denotes -O- or -NR3- (where R3 is H, alkyl group of 1-10C, or the same as R2); R4 is H or -COXR2. The resilience and flexibility of the photosensitive layer are thereby improved and the printing resistance of the printing plate is improved.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a waterless lithographic printing original plate that can be printed without dampening water, and in particular to a waterless lithographic printing original plate that has excellent printing durability. It concerns the original version.

"Prior art" Waterless lithographic printing is basically a printing area and a non-printing area on almost the same plane, with the printing area being ink-receptive and the non-printing area being ink-repellent. In the lithographic printing method, which takes advantage of the difference in ink adhesion to apply ink only to the image area, and then transfers the ink to a printing medium such as paper, the non-image area is made of silicone. It refers to a printing method that consists of a layer of an ink-repellent material such as rubber or a fluorine-containing compound, and allows printing without using dampening water.By the way, this waterless lithographic printing plate has excellent practical properties. For example, for positive working, a silicone rubber layer is used as an ink-repellent material layer, and for example, Japanese Patent Publication No. 54-2692 is used for positive working.
3, etc., and for negative working, there are Japanese Patent Application Laid-open No. 55-59466 and Japanese Patent Application Publication No. 56-80046. In particular, Japanese Patent Application Laid-Open No. 56-80046 can be said to describe a plate construction having high practical performance for negative working.

The printing plate proposed here is a presensitized lithographic printing plate in which a silicone rubber layer is provided on a photoreleasable photosensitive layer backed by a support, and the photosensitive layer is naphthoquinone-
A compound in which a partial ester compound of 1,2-diazido-5-sulfonic acid chloride and a phenol novolak resin is crosslinked with a polyfunctional incyanate has been disclosed.

These conventional waterless planographic printing plates have the following problems. In other words, since the photosensitive layer is relatively brittle and hard, it is easily damaged by the stress applied to the plate surface during printing, and as the number of sheets printed increases, damage to the photosensitive layer under the silicone rubber layer in the non-image area spreads to the silicone rubber layer. Put it away. As a result, localized shedding of the silicone rubber layer occurs, and ink adheres to areas that should normally be non-printing areas, resulting in deterioration in printing quality such as staining of printed matter. was there. These are mainly due to the lack of printing durability of the printing plate.

[Problems to be Solved by the Invention] The object of the present invention is to eliminate the drawbacks of the above-mentioned prior art and provide a waterless lithographic printing original plate for negative working that has excellent printing durability.

[Means for Solving the Problems] That is, the present invention provides a waterless lithographic printing plate in which a photosensitive layer mainly containing a quinonediazide compound and an ink repellent layer are successively laminated on a substrate, in which the photosensitive layer is made of acrylic acid. The present invention relates to a waterless lithographic printing original plate characterized by containing a derivative copolymer.

The quinonediazide compound used in the photosensitive layer of the present invention is an ester obtained by the reaction of commonly used quinonediazide sulfonic acid or its derivative with a compound having a hydroxyl group (particularly a polymer compound), such as benzoquinone-1,2- Esters of diazide-4- or -5-sulfonic acid and polyhydroxyphenyl, naphthoquinone-
Ester of 1,2-diazide-4= or -5-sulfonic acid and pyrogallolacetone resin, naphthoquinone-1
, 2-diazide-4- or -5-sulfonic acid with phenol-formaldehyde novolac resins, such as naphthoquinone-1,2- of phenol-formaldehyde novolac resins with a degree of esterification of 20 to 80%. Examples include partially esterified diazide-5-sulfonic acid. Alternatively, quinonediazide sulfonic acid or a derivative thereof may be simply mixed with the above-mentioned novolak resin, pyrogallol acetone resin, or the like.

The acrylic acid derivative copolymer used in the present invention refers to a copolymer containing 50 mol% or more of an acrylic acid conductor single group having a structure represented by the following general formula (I>. Two or more types of monomers may be mixed.

? R1 represents hydrogen or an alkyl group having 1 to 10 carbon atoms. X is -〇-1 or -NR3- (here, R3 is H
an alkyl group having 1 to 10 carbon atoms, or the same as R2)
R4 means Hl or -COXR2, respectively.

R2 can be selected from an alkyl group having 1 to 30 carbon atoms, an alkenyl group, and an aryl group having 6 to 30 carbon atoms. For example, methyl acrylate or methyl methacrylate (both are hereinafter abbreviated as methyl (meth)acrylate. Also, in the following explanation, ***(meth)###
are the same abbreviations for both ****### and ****meta###. ), ethyl (meth)acrylate, n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, phenyl (meth)acrylate, naphthyl (meth)acrylate, (meth)acrylamide, etc. These R2 may have a suitable substituent such as a halogen, a hydroxyl group, a nitro group, or an amino group.

In particular, in order to maintain adhesiveness with the silicone rubber layer, it is preferable that the monomer contains a hydroxyl group.

For example, 2-hydroxyethyl (meth)acrylate,
4-Hydroxybutyl (meth)acrylate, 2.3-
Hydroxypropyl (meth)acrylate, 2-hydroxyethyl (meth)acrylamide, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, 1,3-propanediol mono(meth)acrylate, 1,4- Butanediol mono(meth)acrylate, di(2-hydroxyethyl)maleate, a ring-opening reaction product of p-hydroxybenzoic acid and glycidyl methacrylate shown in the following formula (II), a ring-opening reaction product of the following formula (I[ These include the reaction product of salicylic acid and 2-hydroxyethyl methacrylate shown in I).

CH3 CH2-C C=0 CH2(II) 0-CH CH2 CH3 CH2=C C=O CH2(X) CH2 In addition, the monomer which utilizes these hydroxyl groups and introduces a naphthoquinonediazide group to impart photosensitivity The body is also used.

That is, as the photosensitive layer, a mixture of the above-mentioned acrylic acid derivative copolymer and a known quinonediazide compound,
Alternatively, it can be selected from mixtures of acrylic acid derivative copolymers imparted with photosensitivity and known quinonediazide compounds.

The other monomer components of the above-described acrylic acid derivative copolymer are basically not limited as long as they can be copolymerized with the above-described monomer components. For example, styrene, acrylonitrile, vinyl acetate, vinyl chloride,
Such as butadiene.

The weight fraction of the acrylic acid derivative copolymer in the photosensitive layer is 5
% or more, the effect of the present invention is exhibited, but in order to avoid impairing image recyclability and adhesion to the silicone rubber layer, it is preferably 5% or more and less than 50%. More preferably, it is 10% or more and less than 30%.

That is, it is preferable that the weight fraction of the known quinonediazide compound, which is a component other than the above-mentioned acrylic acid derivative copolymer, in the photosensitive layer is 50% or more and less than 95%. More preferably, it is 70% or more and less than 90%.

In addition, the photosensitive layer applicable to the present invention has a structure obtained by modifying the mixture of the above-mentioned quinonediazide compound and acrylic acid derivative copolymer by crosslinking it with a polyfunctional compound or bonding it with a monofunctional compound. This also includes those with. The compounds used to introduce the above-mentioned crosslinked structure include polyfunctional isocyanates such as rosephenylene diisocyanate, 4,4''-diphenylmethane diisocyanate, hexamethylene diinocyanate, isophorone diisocyanate, and adducts thereof, and polyfunctional epoxy compounds such as polyethylene glycol diglycidyl ethers, polypropylene glycol diglycidyl ethers, bisphenol A diglycidyl ether, and trimethylolpropane triglycidyl ether.

These crosslinking reactions proceed by heating,
In order to prevent rapid thermal decomposition of the quinone diazide compound, the heating range is preferably 150° C. or lower, and a catalyst or the like is generally used in combination. Also,
Examples of the modification method include esterification, amidation, and urethanization of the active group of the photosensitive compound. The compound reacted with the active group of the photosensitive compound may be a low-molecular compound or a relatively high-molecular compound, and a method such as graft polymerization of a monomer to the photosensitive compound may be used.

The thickness of the photosensitive layer used in the present invention is about 0.1 to 10
0 microns, preferably about 0.5 to 10 microns is suitable. In addition, in the photosensitive layer used in the present invention,
Improving coating film forming properties within a range that does not impair the effects of the present invention,
It is also possible to add components other than those mentioned above for the purpose of improving adhesion to the support, or to add a dye or the like to make the image visible during development or exposure.

Examples of the ink-repellent layer used in the present invention include silicone rubber and fluorine-containing compounds (for example, rubbers containing fluorine in the molecule), and silicone rubber is particularly preferably used. Such a silicone rubber layer is prepared by diluting a silicone gum composition made of linear polydiorganosiloxane with a crosslinking agent and a catalyst added as necessary in an appropriate solvent, and applying it onto the photosensitive layer and drying it by heating. It is formed by hardening. The linear polydiorganosiloxane referred to here is a polymer having repeating units as shown by the general formula below, where R and R' are alkyl or alkenyl having 1 to 10 carbon atoms, or 6 to 10 carbon atoms.
aryl groups, which may have other suitable substituents.

Further, the repeating units may be different along the polymer main chain. Generally, it is preferable that 60% or more of R and R- are methyl groups, and 40% or less are vinyl groups, phenyl groups, or halogenated phenyl groups.

Such a linear polydiorganosiloxane can be strongly crosslinked, for example, by adding an organic peroxide, but in order to advantageously achieve the object of the present invention, it is preferable to carry out condensation type crosslinking. Among them, linear polydiorganosiloxane with hydroxyl groups at both ends (number average molecular weight 5
,000 to 1.00o, ooo >, it is advantageous to add a condensation type crosslinking agent or a condensate thereof to effect condensation crosslinking. As the condensation type crosslinking agent mentioned here, those represented by the following general formula are preferred.

Rm-3i-xn (m+n=4.n is an integer of 2 or more) where R has the same meaning as R described above, and X is a substituent as shown below.

■Halogen such as CI, Br, I, etc. ■Organic substituents such as H or 0)-1,0CORt, OR2°.

Here, R1, R2, R3, R4, R5, Re have 1 carbon number
10 represents an alkyl group, a substituted alkyl group, a phenyl group, or a substituted phenyl group. R7 is 3 to 10
represents a substituted or unsubstituted alkylene group. Silicone gum compositions that perform such condensation-type crosslinking contain organic carboxylates of metals such as tin, zinc, lead, calcium, and manganese, such as dibutyltin laurate, lead octylate, and naphthenic acid, for the purpose of accelerating the reaction. A catalyst such as lead or chloroplatinic acid may be added.

The preferred composition ratio of the silicone gum composition used in the present invention is as follows.

■Linear polydiorganosiloxane (number average molecular weight from 5,000 to i, ooo, ooo
>100 parts by weight ■ Condensation type crosslinking agent 3 to 70 parts by weight ■ Catalyst
10 parts by weight of O As the solvent for the above silicone gum composition, paraffinic hydrocarbons, isoparaffinic hydrocarbons, cycloparaffinic hydrocarbons, aromatic hydrocarbons, and mixtures thereof are advantageously used. . Typical examples of such hydrocarbons include swamped petroleum products and modified amounts thereof.

The thickness of the silicone rubber layer used in the present invention is approximately 0.5 to approximately 100 microns, in order to maintain printing durability and ink repellency above a certain level and maintain good developability.
More preferably from about 0.5 to about 10 microns.

In the waterless lithographic printing plate used in the present invention, the adhesion between the substrate and the photosensitive layer, and between the photosensitive layer and the silicone rubber layer is extremely important for basic plate performance such as image reproducibility and printing durability. If necessary, it is possible to provide an adhesive layer between each layer or add an adhesion improving component to each layer. In particular, for adhesion between the photosensitive layer and the silicone rubber layer, it is effective to provide a known silicone primer or silane coupling agent layer between the layers, or to add a silicone primer or silane coupling agent to the silicone rubber layer or photosensitive layer. .

The substrate of the lithographic printing plate used in the present invention must be flexible enough to be attached to a normal lithographic printing machine and must be able to withstand the load applied during printing. Typical examples include metal plates such as aluminum, copper, and iron, plastic films such as polyester films and polypropylene films, coated paper, and rubber.

The substrate may be a composite of these. Further, it is also possible to provide a rough coating or the like on these substrates for the purpose of preventing halation or the like.

A protective film may be laminated on the surface of the silicone rubber layer of the waterless lithographic printing plate constructed as described above for the purpose of protecting the silicone rubber layer to the extent that the effects of the present invention are not impaired. is also possible.

A waterless lithographic printing plate having the configuration as described above is manufactured by a commonly used coating method.

Next, the exposure and development process of a waterless lithographic printing plate will be explained. The waterless lithographic printing plates described above are exposed to light by a conventional light source, for example through a vacuum sealed negative film. Examples of light sources used in this normal exposure process include high-pressure mercury lamps, carbon arc lamps, xenon lamps, metal halide lamps, and fluorescent lamps. After such normal exposure, when the plate surface is rubbed with a developing pad containing a developer, the silicone rubber layer in the exposed area is removed and the ink receiving area is exposed. If the photosensitive layer is not crosslinked or modified, part or all of its thickness will fall off during the development process, and the exposed surface will become an ink receiving area after the development process. In addition, in the case of a photosensitive layer that has been made insoluble in a developer by crosslinking or modification, it remains without substantially reducing its thickness, and the exposed surface of the photosensitive layer becomes an ink receiving area. becomes.

[Example 1. Comparative Example 1 The following photosensitive layer composition (however, the number of added parts of copolymer (b) below was changed as shown in Table 1) was spin-coated on a chemical conversion treated aluminum plate (thickness 0.3 mm) manufactured by Sumitomo Metal ■. , 120℃, 2
A photosensitive layer having a thickness of 3.5 microns was formed by heat treatment for minutes.

(a) Phenol novolak resin with a degree of esterification of 44% (Sumilight Resin PR50235, manufactured by Sumitomo Duress)
100 parts by weight of naphthoquinone-1,2-diazide-5-sulfonic acid ester (hereinafter referred to as ODA) (b) 2-hydroxyethyl methacrylate/2-ethylhexyl methacrylate copolymer [composition ratio: 80/2
0 (molar ratio), weight average molecular weight 125,000]
(hereinafter referred to as copolymer 1) (c) 20 parts by weight of 4.4-diphenylmethane diisocyanate (d) 0.2 parts by weight of dibutyltin dilaurate (e) 2000 parts by weight of ethyl cellosolve acetate. After spin-coating a silicone rubber composition of the composition, it was cured by heating at 120°C for 2 minutes to a thickness of 2.
A 2 micron layer of silicone gum was applied.

(a) Polydimethylsiloxane with OH at both ends (molecular weight:
40,000) 100 parts by weight (b) Vinyltris(methylethylketoxime)silane
8 parts by weight (C) 0.1 parts by weight of γ-aminopropyltriethoxysilane (d) 0.2 parts by weight of dibutyltin diacetate (e) 1800 parts by weight of Isopar E (manufactured by Etsuso ■) Obtained as above A negative film having a halftone dot image of 150 lines/inch was vacuum-adhered to the original printing plate, and exposed for 60 seconds from a distance of 1 m using a metal halide lamp (Idol Fin 2000.2, manufactured by Iwasaki Electric). When immersed in a developer (Isopar E/Ethanol - 9/1; weight ratio) for about 1 minute and rubbed lightly with a developing pad, only the silicone rubber layer in the exposed areas is removed, resulting in a photosensitive film that faithfully reproduces the image of the negative film. A printing plate with exposed layers was obtained.

Using these printing plates, a forced printing durability test was conducted under the following conditions, and the results are shown in Table 1 (the ink stain status of the printed matter was visually judged, ○: no stain, X: stain).

Printing conditions Printing machine: Hamada Star 700 direct printing modified machine Printing Pressure underlay 500μ Ink: “OPI Process tJN Eye” manufactured by Osaka Ink In addition, halftone reproducibility (○: good, △ smear/bad, X: bad (practical) (no sex)) was shown at the same time. As is clear from Table 1, the addition of the acrylic acid derivative copolymer clearly improved the printing durability of the printing plate.

Example 2 In the photosensitive layer described in Example 1, a copolymer of triethylene glycol acrylate and lauryl methacrylate [composition Ratio: 75/25 (molar ratio>, weight average molecule m 9,000) A lithographic printing plate having the same structure except that it used (hereinafter referred to as copolymer 2) was prepared, and Example 1 was prepared.
A forced printing durability test was conducted under the same conditions as above, and the results are shown in Table 2.

As is clear from Table 2, the addition of the acrylic acid derivative copolymer clearly improved the printing durability of the printing plates.

Example 3 Chemical conversion treated aluminum plate manufactured by Sumitomo Metals (thickness 0.311110
) was spin-coated with a photosensitive layer composition having the following composition, and
A photosensitive layer having a thickness of 3.8 microns was formed by heat treatment at .degree. C. for 2 minutes.

(a) Phenol novolak resin with a degree of esterification of 44% (Sumilight Resin PR50235, manufactured by Sumitomo Duress)
100 parts by weight of naphthoquinone-1,2-diazide-5-sulfonic acid ester (b) 2-hydroxyethyl methacrylate/2-ethylhexyl methacrylate copolymer [composition ratio: 80/2
0 (molar ratio), @weight average molecular weight 125,000] See Table 3 for the number of parts added. Heat and harden for 3 minutes to a thickness of 3.
A micron silicone gum layer was provided.

(a) Polydimethylsiloxane with OH at both ends (molecular weight:
80,000> 100 parts by weight (b) Vinyl tris(methyl ethyl ketoxime) silane
6 parts by weight (C) 0.2 parts by weight of dibutyltin diacetate (d) Di-n-butoxybis(acetylacetonate)
Titanium 2 parts by weight Using the printing original plate thus obtained, the printing plate was subjected to exposure and development in the same manner as in Example 1, and then a printing durability test was conducted in the same manner as in Example 1. As a result, acrylic The addition of the acid derivative copolymer clearly improved the printing durability of the printing plate.

[Effects of the Invention] According to the present invention, the flexibility and flexibility of the photosensitive layer of a waterless lithographic printing plate can be improved, so that the printing durability of the printing plate can be improved.

Table 1 ■Photosensitive layer composition (dry coating film formation 1) QDA/copolymer 1/4.4'-diphenylmethane diincyanate/diptyltin dilaurate 83.2/16.6
10.2 [wt%] Table 2 Table 3 ■Photosensitive layer composition (dry film formation attack) ODA/Copolymer 1

Claims (1)

[Claims] A waterless planographic printing plate comprising a photosensitive layer mainly containing a quinone diazide compound and an ink repellent layer sequentially laminated on a substrate, wherein the photosensitive layer contains an acrylic acid derivative copolymer. Original plate for printing.