JPH0365539B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lithographic printing plate that does not require dampening water and has a silicone rubber layer as an ink repellent layer, and particularly the lithographic printing plate that has improved adhesion between the silicone rubber layer and the photosensitive layer. It is related to.

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

Among these, for example, Japanese Patent Application Laid-Open No. 56-80046 discloses a photosensitive layer lined with a support and a lithographic printing plate that does not require dampening water and is used for negative working. A presensitized lithographic printing plate has been proposed in which a silicone rubber layer is provided on a peelable photosensitive layer. Further, JP-A-55-110249 proposes a lithographic printing plate in which a silicone rubber layer containing aminosilane is provided on a photo-soluble photosensitive layer backed by a support.

In such printing plates, for example, the silicone rubber layer in unexposed areas may peel off during development, or the silicone rubber layer may be difficult to connect to the photosensitive layer due to its scratch resistance and printing durability during operations such as development and printing. Strong adhesion with the silicone rubber layer is most important.

Unexamined Japanese Patent Publication No. 49-57903, 49-73202, 49-77702, 49
No.-86103 and No. 49-126407 both describe a plate structure for improving the adhesion between a silicone rubber layer and a photosensitive material layer, and do not particularly distinguish between negative working and positive working. Furthermore, for negative working, there is Japanese Patent Application Laid-Open No. 55-59466. However, as described in these documents, a silane coupling agent or a silicone primer may be mixed into the silicone layer, or the silicone layer may be a mixture of a one-component room-temperature curing silicone rubber and a two-component addition-type silicone rubber. This means that the silicone rubber layer lacks homogeneity and the cohesive force of the silicone rubber is reduced, resulting in a silicone layer that has poor scratch resistance, and the plate surface is easily scratched during development printing, resulting in scumming. In addition, the technique of mixing a silane coupling agent or an amine compound into the photosensitive material layer generally tends to cause side reactions with highly reactive photosensitive materials, and there are also problems in terms of storage stability.

In order to eliminate these drawbacks and strengthen the adhesion between the photosensitive layer and the silicone rubber layer, an adhesive layer is provided between the photosensitive layer and the silicone rubber layer thereon to bond and bond both layers. It has been proposed (Japanese Unexamined Patent Publication No. 55-59466). The adhesive layer proposed here uses aminosilane. However, when applying aminosilane,
The disadvantage is that the stability of the coating liquid is poor. Furthermore, when considering the adhesion balance between the silicone rubber layer and the photosensitive layer (for example, the adhesion between the silicone rubber layer and the photosensitive layer is strong, but the silicone rubber layer needs to be removed very easily during development), the coating conditions must be adjusted. It is difficult to select the optimum coating amount according to various conditions.

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 provides a lithographic printing plate that does not require dampening water and comprises a support, a photosensitive layer containing an orthoquinone diazide compound, an adhesive layer, and a silicone rubber layer in this order, characterized in that the adhesive layer contains an organic titanate. This invention relates to a lithographic printing plate that does not require dampening water.

The organic titanate used in the adhesive layer of the present invention is a compound represented by the following formula.

Ti(OR ₁ ) ₄ , Ti(OR ₂ ) _o (OCOR ₃ ) _4-o , Ti
(OR ₂ ) _o L _4-o [Here, R ₁ and R ₃ are alkyl having 1 to 20 carbon atoms,
Aryl, cycloalkyl or alkenyl group R ₂ is hydrogen, alkyl having 1 to 20 carbon atoms, aryl, cycloalkyl or alkenyl group L is a chelate ligand n is 0 to 3. ] The ligand referred to herein is β-diketone, glycol, hydroxycarboxylic acid, ketoester, ketoalcohol, or nitrogen ligand.

Typical examples of the above general formula include:
For example, tetraalkyl titanates such as tetra-iso-propoxy titanium, tetra-n-butoxy titanium, tetrastearoxy titanium.

Di-iso-propoxy bis(acetylacetonato) titanium, di-n-butoxy bis(acetylacetonato) titanium, di-n-butoxy bis(triethanolaminato) titanium, dihydroxy bis(lactato) titanium , tetrakis (2-
Also included are titanium chelates such as titanium (ethylhexanediolite), titanium acylates such as tri-n-butoxytitanium monostearate and titanium tetrabenzoate, or aggregates and polymers thereof.

Others: isopropyl tri(dioctyl phosphate) titanate, isopropyl tris(dioctyl pyrophosphate) titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, bis(dioctyl pyrophosphate) ethylene titanate Phosphorus-containing titanates such as phosphorus-containing titanates may also be used.

These organic titanates include not only one type but also two types.
It is also possible to use more than one species in combination.

The photosensitive layer containing the orthoquinone diazide compound used in the present invention is
A photo-solubilizable photosensitive layer and a photo-peelable photosensitive layer such as those proposed in No. 54-156871 are common.

Therefore, the photo-solubilizable photosensitive layer includes a photosensitive layer in which the ethanol-soluble component containing the orthoquinone diazide compound is 20% by weight or less, preferably 15% by weight or less. An orthoquinonediazide compound has a 1,2-quinonediazide or 1,2-naphthoquinonediazide structure in its molecule, and is usually a compound containing a sulfonic acid derivative, such as orthoquinonediazide sulfonic acid and its derivatives, and a hydroxyl group or an amino group (especially polymer compounds)
It is used in the form of an ester or amide obtained by reaction with

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

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

Further, the photoreleasable photosensitive layer is one in which the silicone rubber layer thereon is removed by development without substantially removing the exposed portion of the photosensitive layer.

Examples of non-diazides constituting such a photosensitive layer include esters of benzoquinone-1,2-diazide sulfonic acid and polyhydroxyphenyl;
Examples include esters of naphthoquinone-1,2-diazide sulfonic acid and pyrogallol acetone resin, and esters of naphthoquinone-1,2-diazide sulfonic 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 photoreleasable photosensitive layer.

For example, as a crosslinking agent used to introduce a crosslinked structure, polyfunctional isocyanates such as paraphenylene diisocyanate,
2,4- or 2,6-toluene diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, or adducts thereof, or polyfunctional epoxy compounds, such as Examples include polyethylene glycol diglycidyl ethers, polypropylene glycol diglycidyl ethers, bisphenol A diglycidyl ether, and trimethylolpropane diglycidyl ether.

These thermal curing processes must be carried out within a temperature range that does not cause loss of photosensitivity of the photosensitive material, usually below 150°C.
For this purpose, a catalyst or the like is used in combination.

In addition, as a method for introducing a component that is poorly soluble or insoluble in the developer, similarly, the active group of the photosensitive compound may be esterified, amidated, or urethanized. 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.

The photoremovable photosensitive layer used in the present invention includes:
A particularly preferred one is obtained by crosslinking or modifying a partially esterified product of naphthoquinone-1,2-diazide-5-sulfonic acid and phenol formaldehyde novolak resin with a polyfunctional or monofunctional isocyanate.

The appropriate thickness of the photosensitive layer of the present invention is approximately 0.1 to 100μ, preferably approximately 0.5 to 10μ; if it is too thin, defects such as pinholes are likely to occur during coating, while if it is too thick, it is disadvantageous from an economic standpoint. It is.

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, and images may be visualized 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 and having the following repeating units.

(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 preferably 60% or more of R is a methyl group.) Such linear organic Polysiloxane can also be sparsely crosslinked to form 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., and are usually linear organic polysiloxanes with hydroxyl groups at the ends. When combined with certain substances, silicone rubbers become deaceticated, oxime-free, alcoholized, 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 approximately 0.5 to 100μ, preferably approximately 0.5 to 10μ; if it is too thin, problems may occur in terms of printing durability, while if it is too thick, it is economically disadvantageous. Not only is
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, adhesion between the support and the photosensitive layer is very important for basic plate performance such as image reproducibility and printing durability, so an adhesive layer may be provided as necessary. It is also possible to add adhesion-improving components to each 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. As a typical example,
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 applying a coating to these sheets for antihalation and other purposes.

A thin protective film may be laminated on the surface of the silicone rubber layer for the purpose of protecting the silicone rubber layer forming the surface of the planographic printing plate that does not require dampening water and is constructed as described above.

As explained above, the lithographic printing plate that does not require dampening water and is used in the present invention is manufactured, for example, as follows.

First, a composition solution to form a photosensitive layer is applied onto the support using a conventional coater such as a reverse roll coater, air knife coater, Meyer bar coater, or a rotary coater such as a Whaler, and then dried and coated as necessary. After heat curing, an adhesive layer is applied on the photosensitive layer in the same manner, and after drying, a silicone rubber solution is applied on the adhesive layer in the same manner, followed by heat treatment at a temperature of usually 70 to 140°C for several minutes. and sufficiently cured to form a silicone rubber layer. If necessary, cover the silicone rubber layer with a protective film using a laminator or the like.

The thus produced lithographic printing plate, which does not require dampening water, is exposed to actinic light through, for example, a negative film sealed in vacuum. The light source used in this exposure process emits abundant ultraviolet light, and can be a mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, or the like.

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 printing plate of the present invention not only has strong adhesion between the photosensitive layer and the silicone rubber layer, but also allows the silicone rubber layer to be selectively and easily peeled off from the areas to be removed during the development operation.
Therefore, it is a well-balanced printed edition.

Furthermore, a wide range of conditions can be adopted when applying the adhesive layer.

Furthermore, the adhesive layer coating solution has very good stability as a stock solution, and when an alcohol such as n-butanol is added as a coating solvent, it does not become cloudy and retains its performance even when left in the air for a long time.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A phenol novolac resin (manufactured by Sumitomo Bakelite: manufactured by Sumitomo Bakelite: violet resin
PR50235) naphthoquinone-1,2-diamide
A 10% by weight solution of 5-sulfonic acid ester in dioxane was applied and dried in hot air at 60°C to form a photosensitive layer with a thickness of 3 μm.

On top of this, 0.4% by weight of di-n-butoxy bis(acetylacetonato)titanium (Etsuo Chemical Co., Ltd.)
A solution of "Isoper E" (manufactured by aliphatic hydrocarbon solvent) was applied and dried at 120°C to form an adhesive layer with a thickness of 0.1μ.

Furthermore, a 10% by weight n-hexane solution of a silicone rubber composition having the following composition is applied on top of this,
A silicone rubber layer with a thickness of 2.5 μm was provided by heat curing in hot air at 120° C. for 4 minutes.

(a) Dimethylpolysiloxane (molecular weight 30,000, terminal hydroxyl group) 100 parts (b) Methyltriacetoxysilane 6 parts (c) Dibutyltin acetate 0.2 parts Exposure was carried out for 90 seconds from a distance of 1 m using a high-pressure mercury lamp (jet light 2 kW). When the exposed plate is wetted with a developer consisting of 65 parts of ethanol/35 parts of Isopar E and lightly rubbed with a developer pad, the exposed areas are easily removed and the rubber layer is exposed, while the unexposed areas are left unexposed. A printing plate was obtained in which the silicone rubber layer remained firmly and faithfully reproduced the negative film.

This printing plate was attached to a regular flatbed letterpress printing machine and printed directly onto coated paper using waterless lithographic ink "Alpo G" (manufactured by Toka Shiki Kagaku Kogyo). A printed matter with a good inking state and a sharp image was obtained.

Example 2 Naphthoquinone of phenol novolac resin (Sumitomo Durez: Sumiresin PR50235) with a degree of esterification of 44% was applied to a chemically treated aluminum plate (manufactured by Sumitomo Light Metals).
A 3 wt% dioxane solution of 1,2-diamido-5-sulfonic acid ester (ethanol soluble component: 9.7 wt%) was spin-coated using a Whaler and dried.
A 1.2 μm photosensitive layer was formed.

On top of this, 0.2% by weight of di-n-butoxy bis(acetylacetonato)titanium (Etsuo Chemical Co., Ltd.)
Manufactured by: Aliphatic hydrocarbon solvent) “Isopar E”/
A solution of n-butanol in a weight ratio of 80/20 was spin-coated using a Whaler and dried to form an adhesive layer of 0.05 μm.

A 7% Isopar E solution of a silicone rubber composition having the following composition was spin-coated onto this using a Whaler. After drying, it was cured by heating at 120°C for 4 minutes to obtain a 2.2μ silicone rubber layer.

(a) Dimethylpolysiloxane (molecular weight 80,000, terminal hydroxyl group) 100 parts (b) Vinyl tri(methyl ethyl ketoxime) silane 6 parts (c) Dibutyltin diacetate 0.2 part 150 The film was irradiated for 60 seconds from a distance of 1 m using a metal halide lamp (manufactured by Iwasaki Electric: Idolfin 2000) through a negative film having a line halftone image. The exposed plate was developed using a developer consisting of 8 parts of ethanol and 2 parts of Isopar E through an automatic developing machine at a transport speed of 30 cm/min. The exposed area was easily removed and the chemical conversion treated aluminum surface was exposed. On the other hand, the silicone rubber layer remained firmly in the unexposed areas, and an image faithfully reproducing the negative film was obtained.

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, 5 to 95% of the 150-line halftone dots were reproduced. A printed matter with an extremely good image was obtained. Even after 10,000 copies had been printed, no scumming or damage to the plate surface was observed, and printing could continue.

Example 3 (A) A resol resin (Sumilight Resin PC-1, manufactured by Sumitomo Decorez) was applied to a thickness of 1.7 μm on an aluminum plate (manufactured by Sumitomo Light Metals) with a thickness of 0.24 mm, and it was cured at 180°C for 3 minutes and supported. As a body. On this support, the following photosensitive layer composition was spin-coated at 120°C.
It was cured by heating for a minute to form a photosensitive layer with a thickness of 2.3 μm.

(a) Naphthoquinone-1,2-diazide-5- of phenol novolak resin (Sumilight Resin PR50235, manufactured by Sumitomo Decorez) with a degree of esterification of 48%
Sulfonic acid ester 100 parts (b) 4,4'-diphenylmethane diisocyanate
30 parts (c) 0.2 parts of dibutyltin dilaurate (d) 2000 parts of dioxane (B) Next, apply a 5% by weight Isopar E solution of tetra-iso-propoxy titanium on this using a Meyer bar coater, and then heat at 120°C for 1 minute. Heat and thicken
An adhesive layer of 0.2μ was provided.

(C) Then, after applying a silicone rubber composition with the composition below using a Meyer bar coater,
Heat cured at 120℃, DP30℃, 4 minutes to a thickness of 2.3μ
A silicone rubber layer was provided.

(a) Dimethylpolysiloxane (molecular weight 25,000, terminal hydroxyl group) 100 parts (b) Ethyltriacetoxysilane 6 parts (c) Dibutyltin acetate 0.2 parts The printing original plate obtained as above had a 150-line halftone image. The negative film was vacuum-adhered according to a conventional method, and imagewise exposed using a metal halide lamp. Next, this plate is immersed in Ethyl Cellosolp/Isopar E (manufactured by Etsuo Chemical Co., Ltd.) (5/95) developer and rubbed lightly with a pad to remove the exposed silicone rubber layer and expose the surface of the photosensitive layer, forming the original film. A faithful image was obtained.

The unexposed silicone rubber layer of this plate is not attacked by the developer, and the surface of the silicone rubber layer is not scratched during development. Moreover, the printing plate obtained in this manner can provide excellent printed matter without scratches on the plate surface due to paper dust etc. even during printing.

Claims (1)

[Scope of Claims] 1. A dampening water-free lithographic printing plate comprising a support, a photosensitive layer containing an orthoquinonediazide compound, an adhesive layer, and a silicone rubber layer in this order, characterized in that the adhesive layer contains an organic titanate. A lithographic printing plate that does not require dampening water. 2. The dampening water-free lithographic printing plate according to claim 1, wherein the organic titanate is at least one compound represented by the following formula. Ti(OR ₁ ) ₄ , Ti(OR ₂ ) _o (OCOR ₃ ) _4-o , Ti
(OR ₂ ) _o L _4-o [Here, R ₁ and R ₃ are alkyl having 1 to 20 carbon atoms,
Aryl, cycloalkyl or alkenyl group R ₂ is hydrogen, alkyl having 1 to 20 carbon atoms, aryl, cycloalkyl or alkenyl group L is a chelate ligand n is 0 to 3. ]