JP3239507B2 - Photosensitive lithographic printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a photosensitive lithographic printing plate, and more particularly to a photosensitive lithographic printing plate having an improved intermediate layer.

[0002]

2. Description of the Related Art Conventionally, a photosensitive lithographic printing plate, for example, a negative-working photosensitive lithographic printing plate has a structure in which an ink-receiving photosensitive layer is provided on a support having a hydrophilic layer. When the photosensitive layer of such a photosensitive lithographic printing plate is subjected to image exposure, and then the photosensitive layer is developed using a developing solution, the unexposed portions of the photosensitive layer are removed and the surface of the hydrophilic support is exposed, The photosensitive layer in the exposed area remains on the surface of the support to form an ink-accepting image area, so that it can be used for printing.

As described above, a photosensitive lithographic printing plate forms an ink image by utilizing the repulsion of water and oil, and performs printing. As a specific example, after dampening the non-image portion of the plate surface with dampening water and applying ink to the plate surface, the ink is repelled in the non-image portion, and the ink is selectively supplied only to the image portion,
By transferring this ink to an object to be transferred, a printed matter having an image portion corresponding to the image portion can be obtained.

Therefore, such a photosensitive lithographic printing plate must have excellent hydrophilicity and water retention and good adhesion between the photosensitive layer serving as an image area subjected to printing pressure and the support. No. As a support that satisfies these conditions, an aluminum plate is the most excellent.In order to obtain good adhesion to an image area, for example, mechanical polishing such as ball graining, brush graining, wire graining, etc. The surface is roughened by electrolytic polishing using an electrolytic solution such as nitric acid or hydrochloric acid, or a combination thereof. The surface of the roughened aluminum is often subjected to anodic oxidation using an electrolytic solution such as sulfuric acid or phosphoric acid in order to improve printing durability. Further, in order to control the adhesiveness and water retention of the support, a sealing treatment with hot water, a sealing treatment with a metal silicate or the like is performed.

A photosensitive lithographic printing plate is obtained by coating a photosensitive composition such as an o-quinonediazide compound or an alkali-soluble resin on such a support.

[0006]

However, when a photo-crosslinkable or photopolymerizable photosensitive material, which has been studied as a high-sensitivity photosensitizer in recent years, is used in a photosensitive layer, a conventional processing method does not work. In addition, the adhesiveness between the support and the photosensitive layer was insufficient, and the performance as a photosensitive lithographic printing plate was insufficient.

For this reason, studies have been reported on improving the adhesion between a support and a photosensitive layer using a silane coupling agent as an adhesion improving agent. For example, JP-A-52-520
No. 02 discloses a method of including a silane coupling agent in a photosensitive layer coated on a support. JP-A-59-192250 discloses a method in which a layer containing a silane coupling agent is provided between a support and a photosensitive layer. JP-A-63-50845 discloses a method in which a thin layer comprising at least one silane hydrolysis product or condensate is provided between a support and a photosensitive layer. In Japanese Patent Application Laid-Open No. 3-92391, JP-A-3-92391 discloses a method in which a support is combined with a hydrolysis product or condensate of silane by a general formula MF or M
₂ XF ₆ (M represents an alkali metal, X represents Ti, Zr,
A method of treating with an aqueous solution containing at least one compound represented by Si) is disclosed. However, even when these methods are used and the above-mentioned photosensitive layer is coated and used as a photosensitive lithographic printing plate, the balance between adhesion and stain is insufficient, and a good image is formed. Was difficult.

[0008]

Means for Solving the Problems The inventors of the present invention have made intensive studies to overcome such difficulties and obtain an excellent photosensitive lithographic printing plate. As a result, a layer containing a silane coupling agent on a support and a silicate Alternatively, by providing an intermediate layer containing at least one of an alkali metal salt of hexametaphosphoric acid and a polyvalent carboxylic acid, and then applying the photosensitive layer on the surface, the adhesion between the photosensitive layer and the support is greatly increased. To improve
In addition, the inventors have found that no stain is generated on the non-image portion, and have reached the present invention.

That is, an object of the present invention is to significantly improve the adhesiveness between a photosensitive layer and a support, and to provide a photosensitive material having excellent sensitivity, image reproducibility and chemical resistance without causing stains on non-image areas. To provide a lithographic printing plate. Thus, the purpose of such invention, the photosensitive lithographic printing plate having a photosensitive layer on the support, between the support and the photosensitive layer, silane coupling agent, and an alkali metal salt of silicic acid, hexametaphosphate intermediate layer contains at least one selected from alkali metal salts and the group consisting of polycarboxylic acids acid, or a layer mainly comprising a silane coupling agent, and, thereon, an alkali metal salt of silicic acid at least one mainly characterized by having free an intermediate layer made of a layer containing light-sensitive lithographic printing plate, readily achieved by selected from alkali metal salts and the group consisting of polycarboxylic acids hexametaphosphate You.

Hereinafter, the present invention will be described in detail. The support used in the present invention is preferably a flexible plate which can be set in a normal lithographic printing machine and withstands a load applied during printing, for example, aluminum, magnesium, zinc, chromium iron, copper, a metal plate such as nickel, and the like. Examples thereof include alloy plates of these metals, and further, metal plates coated with chromium, zinc, copper, nickel, aluminum, iron, or the like by plating or vapor deposition may be used. The preferred support among these is aluminum or an alloy thereof.

The support used in the present invention is subjected to a pretreatment such as a degreasing treatment, a graining treatment and an anodic oxidation treatment which are usually employed in this technical field. Examples of the degreasing treatment for removing the rolling oil on the aluminum surface include solvent degreasing with tricrene and thinner, and emulsion degreasing with kerosene and triethanolamine. In addition, in order to remove dirt and natural oxide film that cannot be removed only by degreasing, dipped in an alkali solution such as caustic soda having a concentration of 1 to 10% at 20 to 70 ° C for 5 seconds to 10 minutes, and then a concentration of 10 to 20% In acidic solution such as nitric acid or sulfuric acid at 10-50 ℃
A method of immersing for 2 to 5 minutes to perform neutralization after alkali etching and removal of smut, etc.

The graining treatment method for improving the adhesion to the photosensitive layer and improving the water retention is a so-called mechanical surface roughening method for mechanically roughening the surface.
There is a so-called electrochemical surface roughening method in which the surface is electrochemically roughened. For example, ball polishing,
There are methods such as brush polishing, blast polishing, and buff polishing.
As the electrochemical surface roughening method, for example, there is a method of subjecting a support to electrolytic treatment by alternating current or direct current in an electrolytic solution containing hydrochloric acid or nitric acid. The support can be roughened by using any one or two or more of these methods.

Since smut is formed on the surface of the support which has been subjected to the graining treatment as described above, it is general to appropriately perform a treatment such as washing with water or alkali etching in order to remove the smut. Preferred. When the support used in the present invention is an aluminum support, an oxide film is usually formed on the support by anodic oxidation in order to improve abrasion resistance, chemical resistance and water retention. As the anodic oxidation method, for example, an aqueous solution containing sulfuric acid and / or phosphoric acid at a concentration of 10 to 50% is used as an electrolytic solution to obtain a current density of 1 to 10%.
A method of electrolysis at A / dm ² is preferably used.

After the above pretreatment, an intermediate layer comprising a layer containing a silane coupling agent and at least one selected from the group consisting of an alkali metal salt of silicic acid, an alkali metal salt of hexametaphosphoric acid and a polycarboxylic acid. Alternatively, a layer mainly containing a silane coupling agent and an intermediate layer mainly containing at least one selected from the group consisting of an alkali metal salt of silicic acid, an alkali metal salt of hexametaphosphoric acid, and a polyvalent carboxylic acid are provided. Provided on a support.

The method for providing the intermediate layer on the support may be a conventional method, for example, immersion treatment, roll coating treatment, roll coating treatment, filler treatment (dry method, wet method, Spray method, integral blend method) and the like can be used. Among them, the immersion treatment method is preferable. As the treatment liquid containing the intermediate layer component, a treatment liquid containing a silane coupling agent and at least one selected from the group consisting of alkali metal salts of silicic acid, alkali metal salts of hexametaphosphoric acid and polyvalent carboxylic acids are contained. An intermediate layer having a two-layer structure may be provided by separately applying the treatment liquids, or a silane coupling agent and an alkali metal salt of silicic acid and an alkali metal salt of hexametaphosphoric acid may be provided in a single treatment liquid. Alternatively, an intermediate layer having a single-layer structure may be provided by applying a treatment liquid containing at least one selected from the group consisting of polycarboxylic acids. In particular, after treatment with a solution containing a silane coupling agent, treatment with a solution containing at least one selected from the group consisting of alkali metal salts of silicic acid, alkali metal salts of hexametaphosphoric acid and polyvalent carboxylic acids The intermediate layer obtained is particularly preferred.

In the present invention, the silane coupling agent has at least a tetravalent silicon atom having an organic functional group having affinity or reactivity with an organic material and a hydrolyzing group having affinity or reactivity with an inorganic material. A compound bound directly or via a linking group. Examples of the organic functional group include an amino group, a vinyl group, an epoxyethyl group, a mercapto group, an epoxyethylene group, and the like.Examples of the hydrolyzing group include an alkoxy group, an acyloxy group, and an ammonium compound. Residues and the like. The alkoxy group generally has 1 to 4 carbon atoms such as a methoxy group and a butoxy group. As the acyloxy group, for example, generally an acetyloxy group,
It is selected from alkylcarbonyloxy groups having 2 to 4 carbon atoms such as a butyryloxy group. Examples of the ammonium compound residue include a quaternary ammonium compound residue such as an octadecyldimethylammonium chloride residue. These groups may have a substituent such as an alkyl group.
-Methylvinyl group, β-methoxyethoxy group, anilino group, bis (β-hydroxyethyl) amino group and the like. The alkyl group generally has 1 to 4 carbon atoms such as a methyl group and a butyl group.

Examples of the atom bonded directly to the silicon atom or via a linking group include a halogen atom such as a chloro atom. Examples of the linking group include an alkylene group such as an ethylene group, a propylene group, a trimethylene group and a tetramethylene group, an alkyleneoxyalkylene group such as a trimethyleneoxymethylene group and an ethyleneoxyethylene group, and an alkyleneaminoalkylene group such as a trimethyleneaminoethylene group. Alkyleneoxycarbonyl groups such as a group, an ethyleneoxycarbonyl group and a trimethyleneoxycarbonyl group (where the alkylene group is directly bonded to a silicon atom), and an alkyleneaminoalkyleneaminophenylene group such as a trimethyleneaminoethyleneaminomethylenephenylene group ( However, an alkylene group is directly bonded to a silicon atom.). The alkylene group generally has 1 to 5 carbon atoms,
Examples of the alkyleneoxyalkylene group include those having 2 to 8 carbon atoms.
And the alkyleneaminoalkylene group generally has 2 to 8 carbon atoms, and the alkyleneoxycarbonyl group generally has 2 to 5 carbon atoms. As the alkyleneaminophenylene group, one having 9 to 15 carbon atoms is generally used. The above-mentioned epoxyethyl group is bonded to a linking group to form, for example, β- (3,4-epoxycyclohexyl)
Like an ethyl group, it binds to a silicon atom as an epoxycycloalkyl group.

The silane coupling agent of the present invention further comprises:
Disilazane compounds such as hexaalkyldisilazane are also included. Examples of the solvent for dissolving the silane coupling agent include water, for example, organic solvents such as methanol, ethanol, and methyl cellosolve, and water and, for example, methanol, ethanol, acetone, methyl cellosolve, ethyl cellosolve, and dioxane. A mixed solvent with an organic solvent miscible with water is preferably used, but water is particularly preferred.

The temperature of the processing solution during the surface treatment with the processing solution containing the silane coupling agent of the present invention is generally from 0 to 100.
° C, and preferably from 20 to 80 ° C. The concentration of the silane coupling agent in the surface treatment solution is generally in the range of 0.001 to 10% by weight, preferably in the range of 0.1 to 1.0% by weight. Processing time is generally 10 to 90 seconds, preferably 20 to 90 seconds.
~ 70 seconds. After the silane coupling agent treatment,
It is preferable to perform a water washing treatment. By the water washing treatment, excess silane coupling treatment liquid can be washed away, and the covalent bond between the organic functional group and the hydrolyzable group can be promoted.

The metal silicate in the present invention is not particularly limited, and examples thereof include metal salts of aluminum, magnesium, sodium, potassium and the like, and sodium silicate is particularly preferable. The metal salt of hexametaphosphate in the present invention is not particularly limited, but includes, for example, metal salts of potassium, calcium, sodium, iron and the like, and sodium hexametaphosphate is particularly preferable. Further, the polyvalent carboxylic acid in the present invention is not particularly limited, and examples thereof include oxalic acid, malonic acid, succinic acid, adipic acid, amalic acid, and maleic acid, and oxalic acid is particularly preferred.

The concentration of the treatment liquid is appropriately selected according to the treatment liquid. For example, in the case of sodium silicate, 0.1 to 2.0% by weight, and in the case of sodium hexametaphosphate, 0.1 to 1. 5% by weight, 0.1 ~ for oxalic acid
Generally, it is generally suitably selected from the range of 1.5% by weight. The bath temperature during the surface treatment is generally 20 to 100.
° C, and preferably from 30 to 80 ° C. The processing time is usually in the range of 10 to 60 seconds. It is desirable that the support subjected to the above treatment is subjected to a water washing treatment and then dried. The drying temperature at this time is generally selected from 0 to 300 ° C, preferably from 20 to 300 ° C.
It is selected from 150 ° C. The drying time is generally 2 to
It is selected from 10 minutes, preferably from 3 to 8 minutes.

The photosensitive layer is formed on a layer containing the above-mentioned silane coupling agent and a layer containing at least one of the group consisting of an alkali metal salt of silicic acid, an alkali metal salt of hexametaphosphoric acid and a polyvalent carboxylic acid. The lithographic printing plate material of the present invention can be obtained by providing a photosensitive layer composed of a hydrophilic composition. As the photosensitive composition used in the photosensitive layer, various ones conventionally used for lithographic printing plate materials can be used, and representative ones will be described below. (1) Photosensitive resin composition The composition is made of a photosensitive resin having an unsaturated double bond in the molecule, and is not particularly limited. For example, US Pat.
Nos. 0,208, 3,435,237 and 3,
No. 622,320, the polymer main chain has a crosslinkable unsaturated group.

Embedded image There is a polyvinyl cinnamate having a crosslinkable unsaturated group in a side chain of a photosensitive resin or a polymer containing a.

(2) Photopolymerizable photosensitive composition Monomer having a plurality of addition-polymerizable unsaturated groups and binder
(Polymeric compound) and is not particularly limited.
For example, US Patent Nos. 2,760,863 and 2,79
And photosensitive compositions described in JP-A Nos. 1,504 and 3,801,328.

(3) Photosensitive Compound Containing Diazo Compound The diazo compound is not particularly limited. For example, a diazo resin such as a condensate of an aromatic diazonium salt and formaldehyde can be suitably used. Specific examples include salts of condensates of p-diazodiphenylamine with formaldehyde or acetaldehyde.

As the photosensitive composition used in the present invention, a photopolymerizable photosensitive composition is particularly preferred.

[0026]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist. A 0.3 mm thick aluminum plate (material 1050) is degreased in a 5.0% aqueous sodium hydroxide solution at 65 ° C for 1 minute, washed with water, immersed in a 10% aqueous nitric acid solution at 25 ° C for 1 minute, After being washed, it was washed with water.
This aluminum plate is placed in a 0.3 mol / l nitric acid aqueous solution at 30 ° C.
And then subjected to electrolytic surface roughening at an alternating current density of 50 A / dm ² for 30 seconds, followed by desmutting at 60 ° C. for 10 seconds in a 5.0% aqueous sodium hydroxide solution. Then in a 20% sulfuric acid solution at a temperature of 20
Anodization was performed at a temperature of 3 ° C., a current density of 3 A / dm ² , and a treatment period of 1 minute, followed by washing with water. The support thus obtained was treated by the following method.

Example-1 A support obtained by the above method was placed in a 1.0% by weight aqueous solution of N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane [TSL8340 manufactured by Toshiba Silicone Co., Ltd.]. Immersed in water at 60 ° C. for 30 seconds, washed with water, and then immersed in a 1.0% by weight aqueous solution of sodium silicate at 60 ° C. for 30 seconds.
Soaked for seconds. This was washed with water and dried at 90 ° C. for 8 seconds to provide an intermediate layer composed of a silane coupling agent and sodium silicate. The coating amount of the intermediate layer is 0.10mg
It was / dm ^2. Then, a photopolymerizable photosensitive solution having the following composition was applied using a spin coater and dried at 80 ° C. for 5 minutes to obtain a lithographic printing plate material of the present invention.

[0028]

(Table 1) (Photosensitive composition coating solution composition) Methyl methacrylate / methacrylic acid copolymer 8.2 g Trimethylolpropane triacrylate 8.2 g Michler's ketone 0.2 g Benzophenone 0.8 g Dioctyl phthalate 0.3 g Victoria pure blue BOH 0.001 g Diethylene glycol dimethyl ether 65 g Further, an aqueous solution of polyvinyl alcohol was applied to the surface, and an overcoat layer having a dry film thickness of 3 μm was provided.

Example 2 The same operation as in Example 1 was performed, except that the substrate was immersed in a 1.0% by weight aqueous solution of sodium hexametaphosphate at 60 ° C. for 30 seconds instead of treating with an aqueous solution of sodium silicate.
The coating amount of the intermediate layer containing the silane coupling agent and hexametaphosphoric acid was 0.1 mg / dm ² . Example-3 Instead of sodium silicate aqueous solution treatment, oxalic acid 1.
The same operation as in Example 1 was performed except that the film was immersed in a 0% by weight aqueous solution at 60 ° C. for 30 seconds. The coating amount of the intermediate layer containing the silane coupling agent and oxalic acid was 0.1 mg / dm ² .

Comparative Example-1 After the treatment with the silane coupling agent, the same operation as in Example-1 was performed except that the aqueous solution of sodium silicate was not used. Comparative Example-2 1% by weight without treatment with a silane coupling agent
The same operation as in Example 1 was performed except that the substrate was immersed in an aqueous solution of sodium silicate at 80 ° C. for 30 seconds.

On the lithographic printing plate thus obtained, a step tabet (manufactured by Kodak) whose light quantity attenuates by 1 / √2 every time the number of steps is increased is brought into close contact with the lithographic printing plate, and irradiation is performed at a distance of 1 m. And exposed to light of 350 to 450 nm obtained through a 1 kW xenon lamp and a glass filter for 10 seconds. Next, the plate was developed with an aqueous solution containing 2% by weight of butyl cellosolve and 1% by weight of sodium silicate to remove an unexposed portion of the photosensitive layer and a part of the intermediate layer. The following tests were performed for sensitivity, halftone dot reproducibility, and printability (printing durability, non-image area stain), respectively.

Sensitivity The number of steps in the obtained step-cured image was taken as the reading sensitivity. Halftone Reproducibility The image after development processing was judged by observing the reproducibility of 95% halftone dots. Printing suitability test The lithographic printing plate was set on an offset printing press to determine the printing durability and the occurrence of stains on the non-image area.

Table 1 shows the results of these evaluations.

[0034]

[Table 2] (In the case of Comparative Example 2, the exposed image was not reproduced due to insufficient adhesiveness, and printing was impossible.)

[0035]

As described above, the photosensitive lithographic printing plate of the present invention is excellent in sensitivity, image reproducibility, and chemical resistance. And excellent performance with no stain on non-image areas.

Continuation of the front page (72) Inventor Hiroshi Ide 14 Sunayama, Hazaki-cho, Kashima-gun, Ibaraki Prefecture Kashima Plant, Mitsubishi Kasei Co., Ltd. (JP, A) JP-A-3-200965 (JP, A) JP-A-63-305360 (JP, A) JP-A-3-182754 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ G03F 7/00 503 B41N 1/08 G03F 7/075 G03F 7/11

Claims (1)

(57) [Claims] 1. A photosensitive lithographic printing plate having a photosensitive layer on the support, between the support and the photosensitive layer, silane coupling agent, and an alkali metal salt of silicate, an alkali metal salt of hexametaphosphate And an intermediate layer containing at least one selected from the group consisting of polycarboxylic acids,
Or a layer mainly comprising a silane coupling agent, and, thereon, mainly containing an alkali metal salt of silicate, at least one selected from alkali metal salts and the group consisting of polycarboxylic acids hexametaphosphate A photosensitive lithographic printing plate characterized by comprising an intermediate layer consisting of two layers.