JPS5860744A - Negative type lithographic plate requiring no dampening water - Google Patents

Abstract

PURPOSE:To accelerate hardening of a silicone rubber layer and to raise adhesion between this and a photosensitive layer, by adding organic titanate and amino silane to the silicone rubber layer. CONSTITUTION:A soln. contg. an orthoquinonediazide compd. is coated on a support with an ordinary coater or a rotary coater such as whirler, dried, and when needed, heat cured, and further when necessary, an adhesive layer is likewise coated and dried. A silicone rubber soln. contg. 0.01-10wt% org. titanate, e.g. titanium tetraisoproxide and 0.05-10wt% aminosilane, e.g. gamma-amino propyltriethoxysilane is likewise coated on said adhesive layer, and heat treated usually at 100-120 deg.C for few min to form a fully hardened silicone rubber layer. When needed, this layer covered with a protective film using a laminator or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negative-working lithographic printing plate that does not require dampening water and has a silicone rubber layer as an ink repellent layer.

In particular, the present invention relates to the lithographic printing plate in which the curing of the silicone rubber layer is accelerated and the adhesion between the silicone rubber layer and the photosensitive layer is improved.

Printing plates having two different configurations have been proposed in order to perform planographic printing without using dampening water using silicone rubber as an ink repellent layer.

Among these, one example is a lithographic printing plate for negative working that does not require dampening water and is formed by coating a silicone rubber layer on a photosensitive layer backed by a support.

Japanese Patent Application No. 54-156871 proposes a presensitized lithographic printing plate comprising a silicone rubber layer provided on a photosensitive layer backed by a support. Further, JP-A-55-11 (1249) proposes a lithographic printing plate in which a silicone rubber layer containing aminosilane is provided on a pre-solubilized photosensitive layer backed by a support.

In such printed editions. For example, during development, a layer of unexposed silicone rubber may peel off.

Also, strong adhesion between the photosensitive layer and the silicone rubber layer is most important from the viewpoint of scratch resistance and printing durability of the silicone rubber layer during operations such as development and printing.

Therefore, known silane-based or titanium-based coupling agents are used as adhesive components. For example, JP-A-5
5-110249. In Japanese Patent Application No. 55-15+5871, a known aminosilane is contained in the silicone rubber layer, and in Japanese Patent Application No. 54-158361, a known silane-based or titanium-based coupling agent is used.

However, when an adhesive component such as aminosilane is added to a silicone rubber layer, there are various problems that must be solved in order to implement this technique.

For example, when aminosilane is added, the cured state of the silicone rubber is insufficient, which reduces the scratch resistance of the silicone rubber layer, and the surface of the silicone rubber layer is likely to be scratched during development and printing, and these scratches cause stains on printed matter. There were some drawbacks, such as:

Furthermore, insufficient curing is not favorable for the shape retention of printing original plates, and there are also drawbacks such as difficulty in stacking original plates in the production process.

Furthermore, the adhesive strength between the photosensitive layer and the silicone rubber layer was not sufficient. In such a case, measures can be taken, such as increasing the amount of the silicone curing catalyst or increasing the amount of aminosilane, but it is difficult to improve the stability of the printing original plate over time without deteriorating it.

Furthermore, when the titanium-based primer tetrakis-(2-ethylhexyl) titanate described in Japanese Patent Application No. 54-158361 was added to silicone rubber as an adhesive component, no effect of improving adhesion was observed; Curing is also insufficient, and a good printing plate cannot be obtained as it is.

The present inventors have conducted intensive studies to solve these problems, and as a result, have arrived at the present invention described below.

That is, the present invention relates to a negative-working lithographic printing plate that does not require dampening water and comprises a support, a photosensitive layer containing an orthoquinone diazide compound, and a silicone rubber layer.

The silicone rubber layer contains 0.0% organic titanate. o1~1
o, I amount z and aminosilane 0.05 to 10% by weight
The present invention relates to the lithographic printing plate characterized in that the above-described additives are added.

The aminosilane used in the present invention plays a role in adhering the photosensitive layer and the silicone rubber layer.

The aminosilane referred to herein generally refers to one represented by the following formula.

HmR'nst (OR'/)4-(m+n) where.

R: unsubstituted or alkyl group having hexasubstituted or disubstituted amino group R', *': alkyl group or aryl group / m: v or 2 n20 or 1, and m+n==1 or 2
satisfy the relationship.

Typical examples include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane.
-(N-(2-aminoethyl)aminocopropyltrimethoxysilane, etc.) The amount of aminosilane contained in the silicone rubber layer is 0.05 to 10% by weight.
A weight ratio of 01 to 4.5 is preferably selected, and if it exceeds 10 weight %, it is not only uneconomical, but also the scratch resistance of the silicone rubber layer deteriorates and it becomes impossible to develop. Furthermore, if the amount is less than 0.005% by weight, the effect will not be significant, so the amount added should be in the above ratio.

The organic titanate used in the present invention has the effect of accelerating the curing of the silicone rubber layer, eliminating the tackiness of the surface, and improving the adhesion between the silicone rubber layer and the photosensitive layer. Such an organic titanate is represented by the following formula.

T1(OR) or T1(OCOR)(OR)4-
n n Here, R is alkyl, aryl, cycloalkyl or alkenyl, and n is 0-3.

Representative examples thereof include tetraalkyl titanates such as tetra-yne-propoxy titanium, tetra-n-butoxy titanium, and tetrastearoxy titanium.

Di-iso-propoxy bis(acetylacetonato) titanium, di-n-butoxy bis(triethanolaminenato) titanium, dihydroxy bis(lactato) titanium, tetrakis(2-ethylhexanediorad) titanium, etc. Titanium chelate, tri-n-butoxytitanium monostearate.

Also included are titanium acylates such as titanium tetrabenzoate, or aggregates and polymers thereof.

The amount of the organic titanate added to the silicone rubber is between 0.01 and 10% by weight, preferably between 0.01 and 5% by weight.

If it exceeds 10% by weight, the developability deteriorates, and in some cases, development becomes impossible, which is not preferable.

If it is less than 0.01% by weight, no effect is seen in accelerating the curing of silicone rubber, and it takes a considerable amount of time before the surface tackiness of the silicone rubber layer becomes a problem, which exceeds the practical time. .

The photosensitive layer containing an orthoquinone diazide compound used in the present invention refers to Japanese Patent Application Laid-Open No. 55-110249 and Japanese Patent Application No.
156871 are generally used. Therefore, as a photo-solubilizable photosensitive layer, an ethanol-soluble component containing an orthoquinonediazide compound should be less than 20% by weight. Preferably, the amount of the photosensitive layer is 15% by weight or less. Orthoquinonediazide metal compound has 1.2-
It has a 1-quinonediazide or 1,2-7toquinonediazide structure and is usually a sulfonic acid derivative, such as orthoquinonediazide sulfonic acid and its derivatives, and a hydroxyl group.

It is used in the form of an ester or amide obtained by reaction with a compound having an amine group (especially a polymer compound).

A preferred photosensitive layer for carrying out the present invention is a partial ester of naphthoquinone-1,2-diazide-5-sulfonic acid of a novolak resin having an esterification degree of 35 to 65.

The novolak resin referred to herein is a novolak type phenol resin obtained by condensing phenol or m-cresol with formaldehyde.

Furthermore, a light-peeling photosensitive layer is one in which the exposed portion of the photosensitive layer is not substantially removed during development. Examples include esters of naphthoquinone-1,2-diazide sulfonic acid and pyrogallol acetone resin, and esters of naphthoquinone-1,2'-diazide sulfo/acid and phenol formaldehyde novolak resin.

Such known quinone diazides are crosslinked with a polyfunctional compound or modified by bonding with a monofunctional compound to make them poorly soluble or insoluble in a developer, thereby forming a light-penetrating photosensitive layer.

For example, as a crosslinking agent used to introduce a crosslinked structure, polyfunctional incyanates (9, for example, paraphenyl diynecyaner) can be used.

2.4- or 2.6-) Luendiincyanate.

4.4-diphenylmethane diisocyanate, hexamethylene diincyanate, inphorone diincyanate, or adducts thereof.

Alternatively, polyfunctional epoxy compounds 1 such as polyethylene glycol diglycidyl ethers, polypropylene glycol diglycidyl ethers, bisphenol A diglycidyl ether, and trimethylolpropane triglycidyl ether can be used.

These thermosetting processes must be carried out at T50° C. or lower for 9 cycles without losing the photosensitivity of the photosensitive material, and for this purpose a catalyst or the like is used in combination.

In addition, as a method of introducing a component that is poorly soluble or insoluble in the developer, there may be similarly mentioned methods such as esterification, amidation, or urethanization of the active group of the photosensitive compound. 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, or a monomer may be graft-polymerized to the photosensitive compound.

Particularly preferred as the photoremovable photosensitive layer used in the present invention is a partially esterified product of naphthoquinone-1,2-diazide-5-sulfonic acid tophenol formaldehyde nopolac resin, which is cross-linked with a polyfunctional or monofunctional incyanate. Obtained by denaturation.

The appropriate thickness of the photosensitive layer of the present invention is about 0.1 to 100 μm, preferably about 0.5 to 10 μm; if it is too thin, defects such as pinholes are likely to occur during coating, while if it is too thick, it is not economical. It is disadvantageous from a viewpoint.

In addition, other components may be added to the photosensitive layer for the purpose of improving coating film formation properties and adhesion to the support within a range that does not impair the effects of the present invention, or other components may be added to the photosensitive layer to make the image visible during development or exposure. It is possible to add dyes etc.

The silicone rubber layer used in the present invention is mainly composed of a linear organic polysiloxane having a molecular weight of several thousand to several hundred thousand having repeating units of the first order.

Here, n is an integer of 1 or more, R is an alkyl group, alkenyl group, or phenyl group having 1 to 10 carbon atoms, and R is 6
Preferably, 0 or more groups are methyl groups. Such a linear organic polysiloxane can be sparsely crosslinked to form a silicone rubber by adding an organic peroxide and subjecting it to heat treatment.

A crosslinking agent is also added to the linear organopolysiloxane. Crosslinking agents used in so-called room temperature (low temperature) curing silicone rubber include acetoxysilane, ketoxime silane, alkoxysilane, aminosilane, amidosilane, etc. 2 Usually linear organic polysiloxanes with hydroxyl groups at the ends. When combined, they become deaceticated, oxime-free, alcohol-dealt, deamined, and deamidated silicone rubbers. Generally, a small amount of an organic tin compound or the like is further added as a catalyst to these silicone rubbers.

The appropriate thickness of the silicone rubber layer is about 0.5 to 100 microns, preferably about 0.5 to 10 microns; if it is too thin, problems may arise in terms of printing durability.

On the other hand, if it is too thick, it is not only economically disadvantageous, but also
It becomes difficult to remove the silicone rubber layer during development, resulting in a decrease in image reproducibility.

In the lithographic printing plate of the present invention, a support and a photosensitive layer.

Adhesion between the photosensitive layer and the silicone rubber layer is very important for basic plate performance such as image reproducibility and printing durability. It is also possible to add an adhesion-improving component to the adhesive. In particular, a known silicone primer or silane coupling agent layer is provided between the nine layers for adhesion between the photosensitive layer and the silicone rubber layer.

It is effective to add a silane coupling agent (aluminum) to the silicone rubber layer, and a silicone primer or a silane coupling agent to the photosensitive layer.

The support must be flexible enough to be set in a normal lithographic printing machine and capable of withstanding the load applied during printing. Typical examples include metal plates such as aluminum, copper, and steel, plastic films such as polyethylene terephthalate, coated paper, and rubber. The support may be composite. It is also possible to provide a support by further coating these sheets for prevention of run-on and other purposes.

In order to protect the silicone rubber layer that forms the surface of the planographic printing plate that does not require dampening water and is constructed as described above, a thin protective film may be laminated on the surface of the silicone rubber layer. As explained above, the lithographic printing plate which does not require dampening water and which is used in the present invention is manufactured, for example, as follows. First, a composition solution to form a photosensitive layer is applied onto a support using a normal coater such as a reverse roll coater, an air knife coater, a Meyer bar coater, or a rotary coater such as a wheller, and then dried and coated as necessary. After heat curing,
If necessary, apply an adhesive layer over the photosensitive layer in a similar manner.

After drying, a silicone gum solution to which organic titanate and aminosilane have been added is applied onto the adhesive layer in the same manner, and heat-treated at a temperature of usually 100 to 120°C for several minutes to fully cure and form a silicone rubber layer. do. If necessary, cover the silicone rubber layer with a protective film using a laminator or the like.
For example, it is exposed to actinic radiation through a vacuum-sealed negative film. The light sources used in this exposure process are those that generate abundant ultraviolet light, such as mercury lamps, carbon arc lamps, and xenon lamps.

Metal halide lamps, fluorescent lamps, etc. can be used.

Next, when the plate surface is rubbed with a developing pad containing a developer, the silicone rubber layer or photosensitive layer in the exposed area is removed, and the photosensitive layer surface or substrate surface is exposed and becomes an ink receiving area.

The developing solution used in the present invention includes aliphatic hydrocarbons (hexane,
Preferably, the following polar solvents are added to aromatic hydrocarbons (toluene, xylene, etc.), or halogenated hydrocarbons (triclene, etc.) (6-butane, Ganlin, kerosene, etc.).

Alcohols (methanol, ethanolate, etc.) Ethers (ethyl cellosolve, dioxane, etc.) Ketones (acetone, methyl ethyl ketone, etc.) Ester M (ethyl acetate, cellosolve acetate, etc.) The plate performance of the lithographic printing original plate will not be impaired by stacking it in the state of cut plates.Furthermore, after exposure, the developed printing plate will have no scratches or other scratches on the surface of the silicone rubber layer, and the developing solution during development will not be affected. An excellent printing plate can be obtained without the silicone rubber layer in the unexposed areas being attacked by organic solvents such as organic solvents.This printing plate is free from scratches on the silicone rubber layer in the unexposed areas even by paper dust and printing ink during printing. As soon as the silicone rubber layer is absorbed and the silicone rubber layer falls off, excellent prints can be obtained.

Examples of the effects obtained by the present invention include the following.

(1) Accelerating the curing state of the silicone rubber layer (2)
In addition to the increased adhesion between the photosensitive layer and the silicone rubber layer, the effects include a dramatic increase in the scratch resistance and solvent resistance of the unexposed silicone rubber layer during development of the printing plate, as well as the printing durability of the printing plate. The present invention will now be described in detail with reference to actual shooting u.

Example 1. Comparative Example 1 (A) A 0.24 mm thick aluminum plate (manufactured by Sumitomo Light Metals) was coated with resol resin (Sumilight Resin PC-1, manufactured by Sumitomo Decorez) to a thickness of 1.7 μm, and heated at 180° C. for 3
It was cured for a minute and used as a support. The following photosensitive layer composition was spin-coated onto this support at 120°C.

It was heated and cured for 2 minutes to form a photosensitive layer with a thickness of 2.6 μm.

(a) Naphthoquinone-1,2-diazide-5-sulfonic acid ester of phenol novolac resin (Sumilight Resin PR50255, manufactured by Sumitomo Tecores) with a degree of esterification of 48% ioo part (b) 4,4'-diphenylmethane diincyanate 30 parts (C) 0.2 parts of dibutyltin dilaurate (d)
Dioxane 2,000 parts (A)
Subsequently, a silicone rubber composition having the composition shown below was coated thereon using a Meyer bar coater, and then heated at 120°C.

A silicone rubber layer having a thickness of 2.3 μm was provided by heating and curing at DP 30° C. for 4 minutes.

(a) Dimethylpolysiloxane (molecular weight approximately 25.0
00, terminal hydroxyl group) 100 parts (1))
and niltri(methylethylketoxime)silane
8 parts (C)° diptyltin diacetate 01 parts (d) γ-aminopropyltrimethoxysilane 0.5 parts (e) Tetra-yne-propoxy titanium 10 parts (
f) 440 parts of Isopar E A negative film having a 150-line halftone image was vacuum-adhered to the printing original plate obtained as described above according to a conventional method, and imagewise exposure was performed using a metal halide lamp. Subsequently, this plate was immersed in Ethyl Cellosolve/Timper E (manufactured by Esso Chemical) (5/95) developer and rubbed lightly with a developing pad to remove the silicone rubber layer in the exposed areas and expose the surface of the photosensitive layer. Images faithful to the original film were obtained.

The unexposed silicone rubber layer of this plate is not attacked by the developer, and there are no scratches on the surface of the silicone rubber layer during development. In addition, the printing plate obtained in this way also has a 9.
Excellent printed matter can be obtained without scratches on the plate surface due to paper dust, etc. On the other hand, in a silicone rubber layer in which tetrayne-propoxytitanium and γ-aminopropyltrimethoxysilane do not coexist, the unexposed silicone comb layer falls off during development, and numerous scratches occur on the surface of the silicone rubber layer. Also when printing.

There were countless scratches on the plate due to paper dust.

Example 2. Comparative Example 2 (A) Made by Sumitomo Metals, chemically treated aluminum plate (thickness 03-
＞The following photosensitive layer composition was spin-coated and heated at 120°C92
It was cured by heating for a minute to form a 1.9 μm photosensitive layer.

(a) Naphthoquinone of phenol novolak resin
1,2-Diazido-5-sulfonic acid ester (Example 1
) 100 copies (b) 2.6-)
Luene diisocyanate 20 parts (C) Dibutyltin dilaurate 0.2 parts (d) Dioxane 2,000 parts (B) Subsequently, a silicone rubber composition having the following composition was applied thereto using a Meyer bar coater, and then heated at 12 o°. a.

It was heated and cured in 4 minutes to form a silicone and rubber layer with a thickness of 2.5 μm.

(a) Dimethylpolysiloxane (molecular weight approximately 80.0
00, terminal hydroxyl group) 100 parts (b)
Vinyltri(methylethylketoxime)silane
8 parts (c) -) Butyltin diacetate 01 parts (d) Di-iso-propoquine bis(acetylacetonate) titanium
2 parts (e) 1 part of γ-aminopropyltriethoxysilane (f) 450 parts of Isopar E A negative film with a halftone image of 150 lines was vacuum-adhered to the printing original plate obtained as described above, and heated with a metal halide lamp. Exposure was performed for 60 seconds from a distance of 1 m. Furthermore, by immersing it in a developer (Isopar E/ethanol = 40/6 Dwt, %) and rubbing it lightly with a development pad, only the exposed silicone rubber layer was removed, and a printing plate that faithfully reproduced the negative film image was obtained. .

Similar to Example 1, this printing plate also did not have any peeling of the silicone rubber layer in unexposed areas during development or printing, nor did any scratches or the like occur on the surface of the silicone rubber layer. On the other hand, printing plates with a silicone rubber layer in which di-iso-propoxy bis(acetylacetonato)titanium and γ-aminopropyltrie'toxysilane do not coexist may cause the silicone rubber layer in unexposed areas to fall off during development. It caused countless scratches.

Example 3 Esterification degree of 44 on chemical conversion treated aluminum plate (manufactured by Sumitomo Light Metals)
A dioxane solution of 6% by weight of naphthoquinone-1,2-nidiazide-5-sulfonic acid ester (ethanol-soluble component: 97% by weight) of phenol novolac resin (manufactured by Jumin Durez; Sumiresin pR5o235.) was spin-coated using a Whaler and dried. A 12 μm photosensitive layer was formed. A 7% Isovar E solution of a silicone rubber composition having the following composition was spin-coated onto this using a Whaler. After drying, 12
The mixture was cured by heating at 0° C. for 4 minutes to obtain a silicone rubber layer with a thickness of 2.2 μm.

(a) Dimethylpolysiloxane (molecular weight approximately 80.0
00, terminal hydroxyl group) 100 parts (b) Vinyltri(methylethylketoxime)silane
6 parts (C) Dibutyltin diacetate 0.2 parts (d) 71 parts γ-aminopropyltriethoxysila (e) Dibutoxy, bis(acetylacetonate)
2 parts of titanium The original printing plate obtained as described above was irradiated for 60 seconds from a distance of 1 m using a metal halide lamp (Idol Fin 2000 manufactured by Iwasaki Electric) through a negative film with a 150-line halftone image attached in vacuum. . The exposed plate was prepared using a developer consisting of 8 parts ethanol, 2 parts Isopar E, and 3 parts c.
The image was developed through an automatic developing machine at a transport speed of m/min.

The exposed areas were easily removed to expose the chemically treated aluminum surface, while the silicone rubber layer remained firmly in the unexposed areas, resulting in an image that faithfully reproduced the negative film.

When this printing plate was attached to an offset printing machine (Komori Sprint 2 Color) and printed using Toyo Ink's "Aquares ST Indigo" without using dampening water, halftone dots 5 to 95 of 150 lines were reproduced. Printed matter with very good images was obtained. Even after printing 10,000 copies, no scumming or damage to the plate surface was observed, and printing could continue.

Example 4 A phenol novolac resin with a degree of esterification of 44 degrees was placed on a composite substrate in which chloroprene rubber N with a thickness of 0.3 mm and a rubber hardness of 60 (Shore A) was provided on an aluminum plate with a thickness of 0.3 mm. Made of Bakelite; Sumiresin PR, 5
A dioxane solution of 10% by weight of naphthoquinone-1,2-diazide-5-sulfonic acid ester of 0235> was applied and dried in hot air at 60°C.

A photosensitive layer with a thickness of 6 μm was provided. A 10% by weight n-hexane solution of a silicone rubber composition having the following composition was applied onto this and cured by heating in hot air at 120°C for 4 minutes to a thickness of 2.
．． A 5μ silicone rubber layer was provided.

(a) Dimethylpolysiloxane (molecular weight 50,00
0 terminal hydroxyl group) 100 parts (b) Methyltriacetoxin 6 parts (C) Dibutyltin acetate 0.2 parts (d) γ-
Aminopropyltrimethoxysilane 05 parts (e) Dibutoxy, bis(ethyl acetoacetate) titanium 6 parts The printing original plate obtained as above was passed through a vacuum-adhesive negative film using an ultra-high pressure mercury lamp (Jet Light 2kw), 1
Exposure was performed for 90 seconds from a distance of m. When the exposed plate is wetted with a developer solution consisting of 65 parts of ethanol/35 parts of Isopar E and lightly rubbed with a developing pad, the exposed areas are easily removed and the rubber layer is exposed, while the unexposed areas are removed. The silicone rubber layer remained strongly and a printing plate that faithfully reproduced the negative film was obtained.

This printing plate was installed in a normal flatbed type letterpress printing machine.
When overprinting was performed on coated paper using the waterless lithographic ink "Albo GJ (manufactured by Toka Shiki Kagaku Kogyo), a printed matter with good ink coverage overall and a sharp image was obtained.

Patent applicant: Toshi Co., Ltd.

Claims (1)

[Claims] fl) In a negative-working lithographic printing plate that does not require dampening water and consists of a support, a photosensitive layer containing an orthoquinonediazide compound, and a silicone rubber layer, the silicone rubber layer contains an organic titanate of 0.01 to 10% by weight and an aminosilane of 0.00% by weight. The above lithographic printing plate, characterized in that the above-mentioned lithographic printing plate contains an additive of 0.05 to 10% by weight.