JPS63213849A - Original plate for waterless planographic printing plate - Google Patents

Abstract

PURPOSE:To improve the printing resistance of a printing plate by forming a photosensitive layer mainly of an acrylic acid deriv. copolymer having a quinone diazide group and hydroxyl group. CONSTITUTION:The acrylic acid deriv. copolymer having the quinone diazide group and hydroxyl group contains the acrylic acid deriv. monomer (A) having at least >=1 either or both of alcoholic hydroxyl group or phenolic hydroxyl group in the R2 part of the formula I. Said copolymer is the copolymer of the acrylic acid deriv which contains further the acrylic acid deriv. monomer (B) having the quinone diazide group in the part of R2 and in which the total of the monomer components (A) and (B) is 50-100mol.%. In the formula I, R1 is H or alkyl group of 1-10C; X1 is -O- or -NR3- (where R3 is H, alkyl group of 1-10C, or the same as R2); R4 is H or -COX1R2. The resilience of the photosensitive layer is 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 particularly to a waterless lithographic printing original plate that has excellent printing durability. It concerns the original version of .

[Prior Art] Waterless lithographic printing is basically a method in which a printed area and a non-printed area are made to exist on almost the same plane, with the printed area made to be ink-receptive and the non-printed part to be 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. Refers to a printing method that consists of a layer of a material that is ink repellent, such as rubber or a fluorine-containing compound, and allows printing without using dampening water.

By the way, waterless lithographic printing plates that have excellent practical performance include those that utilize a silicone rubber layer as an ink-repellent material layer, for example, for positive working, Special Public Service 1977-
26923, and for negative working, JP-A-55-59466 and JP-A-56-80046.
and so on. 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,
As the photosensitive layer, naphthoquinone-1,2-diazide-5-
A compound in which a partial ester compound of sulfonic acid chloride and a phenol novolac resin is crosslinked with a polyfunctional isocyanate 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, the silicone rubber layer may fall off locally, causing ink to adhere to areas that should normally be non-printing areas, resulting in poor printing quality such as staining of printed matter. there were. These are mainly due to the lack of printing durability of the printing plate.

[Problems to be Solved by the Invention] As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that an acrylic acid derivative copolymer having a quinonediazide group and a hydroxyl group can be used as the main component of the photosensitive layer. The inventors discovered that a waterless lithographic printing plate precursor for negative working, which has excellent image reproducibility and excellent printing durability, can be obtained by the method, and the present invention was achieved based on this finding.

[Means for Solving the Problems] That is, the present invention provides a waterless lithographic printing original plate in which a photosensitive layer and an ink repellent layer are successively laminated on a substrate,
The present invention relates to a waterless lithographic printing original plate characterized in that the photosensitive layer is mainly composed of an acrylic acid derivative copolymer having a quinone diazide group and a hydroxyl group.

The acrylic acid derivative copolymer having a quinonediazide group and a hydroxyl group used in the present invention is represented by the following general formula (I).
An acrylic acid derivative monomer (A) having at least one alcoholic hydroxyl group, a phenolic hydroxyl group, or both in the R2 part and an acrylic acid derivative monomer (B) having a quinonediazide group in the R2 part. Contains both as constituent components, and the above (A) and (B)
means a copolymer of an acrylic rti derivative in which the total amount of monomer components is 50 to 100 mol %.

However, in order not to impair the adhesion with the silicone rubber layer or the image reproducibility, it is preferable that the monomer components (A> and (8)) in the copolymer are both present in an amount of 10 mol % or more.

R1 is Hl or an alkyl group having 1 to 1 carbon atoms.
~1o alkyl group, or same as R2) R4 means Hl or 100XI R2, respectively.

An acrylic acid derivative monomer having at least one alcoholic hydroxyl group, phenolic hydroxyl group, or both in the R2 portion (A> is determined by the availability of raw materials, ease of synthesis, and From the viewpoint of the flexibility of the resulting copolymer, monomers can be preferably selected from the following (1) to (5).In addition, two or more of these monomers may be mixed.

(1) An acrylic acid derivative monomer in which R2 is an alkyl group having 2 to 30 carbon atoms and having at least 1 m of hydroxyl groups, such as 2-hydroxyethyl acrylate or 2
-Hydroxyethyl methacrylate (both under Lu
-Abbreviated as hydroxyethyl (meth)acrylate.

Also, in the following explanation, all descriptions of Δ△(meta)○○ are ΔΔ
This is an abbreviation for both ○○ and ΔΔmeta○○. ),
4-hydroxybutyl (meth)acrylate, 2,3-
Dihydroxypropyl (meth)acrylate, trimethylolpropane 7-(meth)acrylate, 2-hydroxyethyl (meth)acrylamide, di(2-hydroxyethyl)maleate, etc. are required.

(2) An acrylic acid derivative monomer R5 in which R2 is represented by the following general formula (II) represents hydrogen or a methyl group. n is 1 to 10o, o
oo, e.g. triethylene glycol mono(meth)
Acrylate, tetraethylene glycol mono(meth)
Examples include acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate with various degrees of polymerization.

(3) R2 is represented by the following general formula (III), and the substitution position of the hydroxyl group may be ortho, meta, or para, and the number of hydroxyl groups may be any one from 1 to 5. In other substitution positions of the aromatic nucleus, hydrogen or carbon number 1
-30 alkyl groups, alkenyl groups, aryl groups having 6 to 30 carbon atoms, halogens, nitro groups, alkoxy groups, carboxyl groups, alkoxycarbonyl groups, amino groups, cyano groups, chloromethyl groups, etc. may be substituted. Also,
These substituents may have other suitable substituents in their structures, and may have ester, ether, or amide bonds.

×2 represents an alkylene group having 0 to 10 carbon atoms, an alkenylene group, -C-Y-Re-X1-1 〇-Y-C-R6-XI-1-Y-Re-X1, and these are hydroxyl groups, etc. It may also have other suitable substituents.

Here, Y is 10- or -NR7-, and R6 has 1 carbon number.
-10 alkylene group, R7 is H or carbon number 1-10
means an alkyl group.

Examples of such compounds include the ring-opening reaction product of p-hydroxybenzoic acid and glycidyl methacrylate shown in the following formula (IV), and the ring-opening reaction product of p-hydroxybenzoic acid and glycidyl methacrylate shown in the following formula (V'), and the product of salicylic acid and 2-hydroxyethyl methacrylate shown in the following formula (V'). There are also reactants with acrylates.

CH3 CH2=CC An alkyl ester having a hydroxyaryl group, an acrylic acid derivative monomer having a glycol ester bond, for example, a reaction product of 2-hydroxyethyl metaarylate and p-hydroxybenzoic acid shown in the following formula (VI), a reaction product of the following formula (■ ), such as a reaction product of diethylene glycol monomethacrylate and p-hydroxybenzoic acid.

CH3 CH2 CH2 CH2 CH2 (■) (5) Hydroxyalkyl having 1 to 30 carbon atoms using the hydroxyl group of R2 described in (3) above or a suitable highly reactive substituent (carboxyl group, etc.) Ester, polyethylene glycol monoester of various degrees of polymerization, acrylic acid derivative monomer having polypropylene glycol ester groups, for example, roughly reacting glycolic acid with the phenolic hydroxyl group of the reaction product of 2-hydroxyethyl methacrylate and salicylic acid. The acrylic acid derivative monomer (B) having a quinonediazide group in the R2 moiety is a compound having a 1,2-quinonediazide or 1,2-naphthoquinonediazide structure in the molecule ( Usually, esters or amides obtained by the reaction of sulfone rli derivatives (for example, orthoquinonediazide sulfonic acid or its derivatives) with the above-mentioned acrylic acid derivative monomer having a hydroxyl group or an amine group of general formula (I) are commonly used. means a compound.

In addition, as a method for introducing a quinone diazide group, (A) a method of copolymerizing acrylic acid derivative monomer (A) and (B>), (B) a method of copolymerizing the acrylic acid derivative monomer (A>) into the polymer of acrylic acid derivative monomer (A>). There is a method of grafting a compound having a quinonediazide structure to form component (B) as a result, and either method can provide a photosensitive layer that can fully exhibit the effects of the present invention.

In addition, monomer components other than the above monomer components (A) and (B) are basically not limited as long as they can be copolymerized with the above (A>, (B)).

For example, styrene, methyl (meth)acrylate, n-
There are various acrylic acid derivatives such as butyl (meth)acrylate, allylonitrile, vinyl acetate, etc., but from the viewpoint of improving printing durability, which is the objective of the present invention, they have a structure that increases flexibility. Preferably, for example,
Lauryl (meth)acrylate, 2-ethylhexyl (
Meth)acrylate and the like are preferably used.

The degree of polymerization of the acrylic acid derivative copolymer having a quinonediazide group and a hydroxyl group used in the present invention is 10 to 100.
．． 000 is preferably used.

Furthermore, the vine photosensitive layer applicable to the present invention has a structure obtained by modifying the above-mentioned acrylic H conductor copolymer by crosslinking it with a polyfunctional compound or bonding it with a monofunctional compound such as a monofunctional isocyanate. This also includes those with. Examples of the compound used to introduce the above-mentioned crosslinked structure include polyfunctional isocyanates such as paraphenylene diisocyanate, 1,4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, These adducts, or polyfunctional epoxy compounds,
Examples include polyethylene glycol diglycidyl ethers, polypropylene glycol diglycidyl ethers, sphenol A diglycidyl ether, and trimethylolpropane triglycidyl ether. These crosslinking reactions proceed by heating, but this heating range usually needs to be carried out at 150°C or below in order to prevent rapid thermal decomposition of the quinone diazide group, and generally a catalyst etc. is used in combination. be done. In addition, as a method for modifying the photosensitive compound, for example, the active group of the photosensitive compound can be modified by
Examples include esterification, amidation, and urethanization. The compound to be 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 100
Microns, preferably about 0.5 to 10 microns, are suitable.

In addition, the photosensitive layer used in the present invention may contain components other than those mentioned above, such as polyurethane, for the purpose of improving coating film formation and adhesion to the support, to the extent that the effects of the present invention are not impaired. resin or a known naphthoquinone site compound may be added.

However, in order not to impair the effects of the present invention, the weight fraction of the acrylic acid derivative copolymer in the photosensitive layer must be 50
% or more, more preferably 70% or more.

That is, it is preferable that the weight fraction of resins other than the acrylic acid derivative copolymer and known quinonediazide compounds is less than 50% in the photosensitive layer.

More preferably it is less than 30%.

It is also possible 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 applying a silicone gum composition prepared by adding a crosslinking agent and a catalyst to a linear polydiorganosiloxane and diluting it with an appropriate solvent onto the photosensitive layer, and drying it by heating. It is formed by hardening. The linear polydiorganosiloxane mentioned here is a polymer having a repeating unit as shown by the general formula below, where R and R- are an alkyl group having 1 to 10 carbon atoms, an alkenyl group, or an alkenyl group having 6 to 1 carbon atoms.
0 aryl groups, which may have other suitable substituents.

Also, 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 polydiosica/siloxane with hydroxyl groups at both ends (Ik average molecular 15
,000 to 1,000,000), a condensed crosslinking agent,
It is advantageous to add condensates or condensates 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) Here, R has the same meaning as R described above, and X is a substituent as shown below.

■ Halogen such as CI, Br, ■ ■ Organic substituents such as H or OH, 0COR1, OR2, etc.

Here, R1, R2, R3, R4, R5, R6 have 1 carbon number
~10 alkyl groups, substituted alkyl groups, phenyl groups, or substituted phenyl groups.

R7 represents a substituted or unsubstituted alkylene group having 3 to 10 carbon atoms. Silicone gum compositions that undergo such condensation-type crosslinking contain organic carboxylates of metals such as tin, zinc, calcium, and manganese, such as dibutyltin laurate, lead octylate, and lead naphthenate, for the purpose of accelerating the reaction. or a catalyst such as 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 5,000 to i, ooo, ooo) 10
0 parts by weight ■ Condensation type crosslinking agent 3 to 70 parts by weight ■ Placement part
0 to 10 parts by weight 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 fractionated petroleum products and reformed products thereof.

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

In the waterless planographic printing plate used in the present invention, 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. Therefore, 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. It is.

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 capable of withstanding 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.

It is also possible to laminate a protective film 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 within a range that does not impair the effects of the present invention. It is.

A waterless lithographic printing plate having the structure as described below is manufactured by a coach ink method commonly used in this field.

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 normal light, for example through a vacuum sealed negative film. Examples of light sources used in this exposure step 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 the photosensitive layer falls off during the development process, and the exposed surface becomes 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 denaturation, it remains without substantially reducing its thickness, and the exposed surface of the photosensitive layer becomes an ink receiving area. becomes.

[Example] Examples are shown below. Parts in the examples are parts by weight.

Example 1 Chemically treated aluminum plate (thickness 0°3mm) manufactured by Sumitomo Metals Co., Ltd.
＞, the following photosensitive layer composition was spin-coated and heated at 120°C for 2 hours.
A photosensitive layer having a thickness of 3.5 microns was provided by heat treatment for a minute.

■ Copolymer of 2-hydroxyethyl methacrylate and 2-ethylhexyl acrylate [composition ratio: 80/2
100 parts of a partially esterified product (degree of esterification 50%) synthesized by grafting naphthoquinone-1,2-diazide-5-sulfonic acid chloride onto 0 (molar ratio), weight average molecular weight 125.000) 4. 4°-diphenylmethane diisocyanate 20
Part ■ Dibutyltin dilaurate 0.2 parts ■ Ethyl cellosolve acetate 2,000 parts Subsequently, a silicone gum composition having the following composition was spin-coated thereon, and 12 parts of dibutyltin dilaurate were applied.
A silicone rubber layer having a thickness of 2.5 microns was provided by heating and curing at 0° C. for 2 minutes.

■ Polydimethylsiloxane with OH at both ends (molecular weight:
20,0OC) > 100 parts■ Vinyltris(methylethylketoxime)silane
8 parts■ γ-aminopropyltriethoxysilane 0.1 part■ ``Isoper E'' (manufactured by Etsuzo Co., Ltd.) 1.800
A negative film with a halftone image of 150 lines/inch was vacuum-adhered to the original printing plate obtained as described above, and a metal halide lamp (idle fin 20000.2 kW,
(manufactured by Iwasaki Electric Co., Ltd.) for 60 seconds from a distance of 1 m. Next, it is immersed in a developer ("ISOPAR E"/ethanol = 9/1; weight ratio) for about 1 minute, and rubbed lightly with a development pad. Only the silicone rubber layer in the exposed areas is removed, and the image on the negative film is faithfully reproduced. A printing plate with a reproduced exposed photosensitive layer was obtained.

On the other hand, in the photosensitive layer, instead of the above-mentioned acrylic acid derivative copolymer, naphthoquinone-1,2-diazide-5-sulfonic acid ester of phenol novolak resin (Sumilight Resin PR50235, manufactured by Sumitomo Duress) with a degree of esterification of 44%, A lithographic printing plate having the same configuration except that 1 was used was prepared, and a forced printing durability test was conducted under the following conditions.

Printing conditions Printing machine: Hamada Star 700 Modified overprinting machine Printing pressure: Underlay 500μ Ink: “OPI Process UN Eye” manufactured by Osaka Ink As a result of the above test, the former printed about 4,000 sheets and the ink was damaged due to damage to the plate surface. Smudges appeared on the printed matter, and the latter appeared after about 750 sheets, clearly showing a difference in the printing durability of the printing plates. It can be seen that the plate using the acrylic acid derivative copolymer as the photosensitive layer has significantly better printing durability.

Example 2 In the photosensitive layer described in Example 1, a copolymer of triethylene glycol acrylate monoester and lauryl methacrylate [composition ratio near 5/25 (molar ratio)] was used instead of the above-mentioned acrylic acid derivative copolymer. , @weight average molecular weight 9,000) and naphthoquinone-1,2-diazide-
A lithographic printing plate having the same structure except that a partially esterified product (degree of esterification: 40%) synthesized by grafting reaction of 5-sulfonic acid chloride was prepared, and the forced printing durability was measured under the same conditions as in Example 1. I conducted a test.

As a result, ink stains due to damage to the plate surface appeared on the printed matter after approximately 3,750 copies were printed, and the printing durability was superior to that of Comparative Example 1.

Example 3 In the photosensitive layer described in Example 1, instead of the acrylic acid derivative copolymer described above, a copolymer of glycidyl methacrylate and a ring-opened adduct of glycidyl groups of p-hydroxybenzoic acid and lauryl methacrylate [composition] Philippines 5/
25 (mole ratio), weight average molecule! A lithographic printing plate having the same structure was prepared except that a partially esterified product (degree of esterification: 45%) synthesized by grafting naphthoquinone-1,2-diazide-5-sulfonic acid chloride onto 12,700) was used. A forced printing durability test was conducted under the same conditions as in Example 1.

As a result, ink stains due to @ scratches on the plate surface appeared on the printed matter after approximately 3,500 copies were printed, and the printing durability was superior to that of Comparative Example 1.

Example 4 In the photosensitive layer described in Example 1, the acrylic r! Instead of the Ii derivative copolymer, a ring-opening adduct of the glycidyl group of glycidyl methacrylate and p-hydroxybenzoic acid, a reaction product of 2-hydroxyethyl methacrylate and naphthoquinone-1,2-diazido-5-sulfonic acid chloride, Ternary copolymer with 2-ethylhexyl acrylate [composition ratio: 50/25/25 (molar ratio),
A lithographic printing plate having the same structure except that a weight average molecular weight of 14,500) was used was prepared, and a forced printing durability test was conducted under the same conditions as in Example 1.

As a result, ink stains due to damage to the plate surface appeared on the printed matter after approximately 4,000 copies were printed, and the printing durability was superior to that of Comparative Example 1.

Example 5 Chemically treated aluminum plate (thickness 0°3mm) manufactured by Sumitomo Metals Co., Ltd.
＞, the following photosensitive layer composition was spin-coated and heated at 120°C for 2 hours.
A photosensitive layer having a thickness of 3.8 microns was provided by heat treatment for a minute.

■ Copolymer of 2-hydroxyethyl methacrylate and 2-ethylhexyl acrylate [composition ratio: 80/2
0 (molar ratio), weight average molecular weight 125.000) with naphthoquinone-1,2-diazide-5-sulfonic acid chloride (degree of esterification 50%) 100 parts Dioxane 1 Subsequently, a silicone gum composition having the following composition was spin-coated thereon and cured by heating at 120'C for 12 minutes to form a silicone rubber layer with a thickness of 3 microns.

■ Polydimethylsiloxane with hydroxyl groups at both ends (molecular weight:
80,000) 'I O0 parts■ Vinyl tris(methyl ethyl ketoxime) silane
Part 6■ Dibutyltin diacetate
0.2 parts ■ di-n-butoxybis(acetylacetonato) titanium 2 parts Using the printing original plate obtained as above, the same exposure and development treatment as in Example 1 was carried out to prepare a printing plate.

On the other hand, naphthoquinone-1,2-diazide-5-sulfonic acid of a phenol novolak resin (Sumilight Resin PR50235, manufactured by Sumitomo Duress) with a degree of esterification of 44% was used instead of the above-mentioned acrylic acid derivative copolymer in the photosensitive layer. A lithographic printing plate having the same structure except that ester was used was prepared, and a forced printing durability test was conducted under the same conditions as in Example 1. As a result, ink stains due to damage to the plate surface appeared on the printed matter after about 2,000 copies were printed in the former case, but stains appeared on the printed matter after about 500 copies were printed in the latter case, and there was clearly a difference in the printing durability of the printing plates. It was done.

[Effects of the Invention] Since the waterless lithographic printing original plate of the present invention is configured as shown in the above (a), it is possible to improve the flexibility and fragility of the photosensitive layer, thereby improving the printing durability of printed matter. can be done.

Claims (1)

[Claims] A waterless lithographic printing original plate comprising a photosensitive layer and an ink repellent layer sequentially laminated on a substrate, wherein the photosensitive layer is mainly composed of an acrylic acid derivative copolymer having a quinonediazide group and a hydroxyl group. Original plate for lithographic printing.