JPH06122288A - Manufacture of photosensitive lithographic printing plate - Google Patents

Abstract

PURPOSE:To obtain a photosensitive lithographic printing plate having moderate adhesion of a supporting body and a photosensitive layer, excellent sensitivity, development eliminating property of an unexposed photosensitive layer, and dot reproducibility of an exposed photosensitive layer. CONSTITUTION:A supporting body oxidized anodically is treated with alkali metal phosphate water solution, alkali metal silicate water solution, and phosphoric acid water solution in sequence. Thereafter, it is coated with a light crosslink type or a photopolymerization type photosensitive composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive lithographic printing plate, and more specifically, it has an improved roughened surface excellent in adhesion to a photosensitive layer composed of a photocrosslinking or photopolymerizable photosensitive composition. And a photosensitive lithographic printing plate having

[0002]

2. Description of the Related Art Conventionally, a photosensitive lithographic printing plate, for example, a negative type photosensitive printing plate, is one in which an ink-receptive photosensitive layer is provided on a support having a hydrophilic layer. When the photosensitive layer is exposed imagewise and then developed, the photosensitive layer in the unexposed area is removed and the surface of the hydrophilic support is exposed, while the photosensitive layer in the exposed area remains on the surface of the support and the To form a photosensitive image portion, whereby a photosensitive lithographic printing plate is obtained.

Such a photosensitive lithographic printing plate is one which prints by utilizing the repulsion between water and oil. Specifically, when the non-image area of the plate surface is moistened with water and then the ink is applied to the plate surface, the ink repels by the dampening water in the non-image area, so that the ink selectively adheres only to the image area. When the ink in the image area is transferred to the transferred material, a printed material having an image corresponding to the image area is obtained.

Therefore, the surface of the support for obtaining the photosensitive lithographic printing plate is excellent in hydrophilicity and water retention when moistened with water, and has an adhesive property with the photosensitive layer which becomes an image portion which receives a printing pressure. Must be good. As a support satisfying these conditions, an aluminum plate is the most excellent, and in order to obtain sufficient adhesiveness between the aluminum plate and the photosensitive layer, a method of roughening the support surface by various methods is available. Proposed. As a surface treatment method for mechanically roughening, for example, each method such as ball graining, wire graining, brush graining, etc.
Japanese Patent Publication, Japanese Patent Publication No. 51-46003, etc.
Further, as an electrochemical graining method, Japanese Patent Publication No. 48-28123, U.S. Pat. No. 4,087,341, JP-A-53-67507
Japanese Unexamined Patent Publication (KOKAI) Publication No. 2003-242977 discloses that a hydrochloric acid bath, a nitric acid bath or the like is used to form a uniform and fine grain shape on the surface of an aluminum plate with a direct current or an alternating current. In addition,
In 1-249494, it is possible to roughen at a frequency of 60 to 140 Hz, and in JP-A 1-178496, it is possible to roughen at a low frequency of 0.5 to 1.5 Hz and then at a high frequency of 10 to 100 Hz. Roughening is described.

Further, the surface of the support thus roughened is generally anodized to form an oxide film. A surface treatment is further performed in order to provide sufficient adhesion between the anodized support and the photosensitive layer and to improve the hydrophilicity and water retention of the support such as an aluminum plate. For example, Japanese Patent Laid-Open No. 56-150595 discloses a method in which a surface of a support is subjected to a sealing treatment with hot water and the like.
No. 2,246,683, U.S. Pat.No. 3,160,50
No. 6 describes a method for improving the hydrophilicity and water retention of the metal surface by chemically treating the metal surface with potassium fluorozirconate to form a film. Further, JP-A-53-131102 describes a support which is treated with an aqueous solution of potassium fluorozirconate and then with an aqueous solution of sodium silicate to improve hydrophilicity and water retention.

[0006]

However, in recent years,
When a photocrosslinking type or photopolymerization type photosensitive material which has been studied as a photosensitive layer for a high-sensitivity material is used, in a support which is anodized in a phosphoric acid solution, the adhesiveness with the photosensitive layer is On the other hand, the anodic oxide film is relatively good, but the conventional technique has a drawback that it is inferior in scratch resistance. In addition, a support anodized in a sulfuric acid solution is relatively good in productivity and scratch resistance, but when a conventional alkali metal silicate solution or the like is used alone, There is a drawback of the prior art that the adhesiveness with the layer is poor.

[0007]

The inventors of the present invention have made earnest studies to overcome these difficulties and obtain an excellent method for producing a photosensitive lithographic printing plate.
By sequentially treating with an alkali metal phosphate aqueous solution, an alkali metal silicate aqueous solution, and a phosphoric acid aqueous solution, the sensitivity,
The inventors have found that a photosensitive lithographic printing plate excellent in both the removability of the photosensitive layer in the unexposed area and the adhesiveness of the photosensitive layer in the exposed area is produced, and arrived at the present invention.

That is, an object of the present invention is a method for producing a photocrosslinking or photopolymerization type photosensitive lithographic printing plate which is excellent in sensitivity, removability of the photosensitive layer in the non-exposed area and adhesion of the photosensitive layer in the exposed area. To provide. Another object of the present invention is to provide a method for producing a photocrosslinking type or photopolymerization type photosensitive lithographic printing plate having appropriate adhesion between a photosensitive layer and a support.

Thus, the object of the present invention is to provide an anodized support with (a) an alkali metal phosphate aqueous solution,
(b) Production of a photosensitive lithographic printing plate characterized by applying a photocrosslinking or photopolymerization type photosensitive composition after treatment in this order with an alkali metal silicate aqueous solution and (c) phosphoric acid aqueous solution Easily achieved by the method. The present invention will be described in more detail below.

The support used in the present invention is preferably one that can be set in an ordinary lithographic printing machine and can withstand the load applied during printing. For example, a metal such as aluminum, magnesium, zinc, chrome iron, copper or nickel. Examples thereof include a plate and an alloy plate of these metals, and a metal plate coated with chromium, zinc, copper, nickel, aluminum, iron or the like by plating or vapor deposition may be used. Of these, the preferred support is aluminum or its alloy.

Since the surface of the support is contaminated with oil and other deposits, it is desirable to degrease and wash it by a conventional method prior to the electrolytic surface roughening treatment. Although not limited, for example, solvent degreasing with trichlene, thinner, etc.,
Emulsion degreasing with kerosene and triethanolamine, etc., in a caustic soda aqueous solution with a concentration of 1-10% at 20-70 ℃
Soak for 10 minutes from second to remove dirt and natural oxide film that cannot be removed only by degreasing, then soak in nitric acid or sulfuric acid aqueous solution with a concentration of 10 to 20% at 10 to 50 ° C for 5 seconds to 5 minutes, and after alkali etching There is a method of neutralizing and removing smut (desmut treatment).

After that, electrolytic surface roughening treatment is performed in an acidic electrolytic solution. The acidic electrolytic solution is not limited, but hydrochloric acid, nitric acid, or the like can be used, and it is more preferable to use an electrolytic solution containing nitric acid as a main component. The conditions for electrolytic surface roughening vary depending on the degree of desired electrolytic surface roughening, and therefore cannot be uniquely determined, but as general electrolytic surface roughening conditions, the concentration is 0.5 to 3.5%, preferably 0.7 to 3.0. %, Temperature 10
~ 40 ℃, preferably 25 ~ 35 ℃, current density 20 ~ 200A / d
A m ² of 40 to 150 A / dm ² and a time of ² to 500 seconds are widely used. The electrolysis frequency may be in the usual range. However, as described in Japanese Patent Application No. 4-206564, a high frequency of 150 to 1000 Hz is more preferable, and a high frequency of 200 to 500 Hz is particularly preferable.

When performing electrolytic surface roughening treatment using such an electrolytic solution, the alternating current used has a waveform obtained by alternately exchanging positive and negative polarities, such as a rectangular wave, a trapezoidal wave, or a Japanese patent publication. Although it may be an AC waveform such as a waveform whose phase is controlled by the thyristor described in Japanese Patent Publication No. 57-22030, an ordinary commercial AC, that is, a sine wave single-phase AC or three-phase AC is sufficient. .

The support that has been electrolytically surface-roughened under the above-mentioned conditions is preferably, but not limited to, subsequently washed with water or alkali-etched to remove smut remaining on the surface. Alkaline etching is performed according to a conventional method, for example, by immersing in an alkaline or acid aqueous solution at 10 to 80 ° C for 5 seconds to 3 minutes to desmut, and then neutralizing with an acidic solution (sulfuric acid, phosphoric acid, nitric acid, etc.) Is more preferably performed.

After that, the support is subjected to anodizing treatment to form an oxide film to improve abrasion resistance, chemical resistance and water retention. The electrolytic solution in the anodizing treatment of the present invention is not limited, but phosphoric acid, sulfuric acid or the like can be used. The electrolyte may contain other electrolyte as long as it is an aqueous solution containing at least about 10 to 50% when using sulfuric acid and about 1 to 10% when using phosphoric acid. The electrolysis conditions are not limited, for example,
The current density is ¹ to 10 A / dm ² and electrolysis is performed for 10 seconds to 2 minutes.

The anodized support may be subjected to, for example, but not limited to, water washing treatment. Then, it is treated with an aqueous solution containing an alkali metal phosphate. Examples of alkali metal salts of phosphoric acid include metal salts such as sodium and potassium, and sodium phosphate is particularly preferable. The treatment conditions vary depending on the state of the support and the type of alkali metal, and therefore cannot be uniquely determined, but when sodium phosphate is used, the concentration is
0.01-1% is preferable, bath temperature is 30-100 ℃
Is preferable, and particularly preferably 50 to 100 ° C. The processing time is preferably 1 to 60 seconds.
Further, other components such as an electrolyte may be added to the alkali metal phosphate aqueous solution as long as the action on the support is not hindered.

The support treated with the aqueous solution of alkali metal phosphate is then treated with an aqueous solution of alkali metal salt of silicic acid. Examples of alkali metal salts of silicic acid include metal salts such as sodium and potassium, and sodium silicate is particularly preferable. The treatment conditions differ depending on the state of the support and the type of alkali metal, so it cannot be uniquely determined.
When sodium silicate is used, the concentration is preferably 0.1-2.0%. The bath temperature during surface treatment is preferably 20 to 100 ° C, and particularly preferably 60 to 90 ° C. The processing time is preferably 1 to 30 seconds. Further, other components such as an electrolyte may be added to the aqueous solution of alkali metal silicate as long as the action on the support is not hindered.

After the treatment with the aqueous solution of alkali metal salt of silicic acid, it is desirable to treat with hot water. The treatment conditions may be according to a conventional method and are not particularly limited, but for example, the bath temperature is 70 to 100 ° C. and the time is 1 to 30 seconds. After that, the adhesiveness with the exposed portion photosensitive layer is improved by immersing in a phosphoric acid aqueous solution. The bath concentration is preferably 0.1 to 2%, and the pH of the aqueous solution is preferably less than 7.
Is particularly preferably less than 5. Bath temperature is 50-100
C is preferable, and particularly preferably 70 to 90 ° C. The time is preferably 1 to 30 seconds. Further, other components such as an electrolyte may be added to the aqueous phosphate solution as long as the action on the support is not hindered.

The support which has been subjected to the above-mentioned treatment may be further subjected to a washing treatment, a drying treatment and the like, and a drying treatment is particularly preferable. The drying temperature is preferably 20 to 300 ° C, particularly preferably 50 to 150 ° C. The drying time is preferably 1 to 10 minutes, more preferably 2 to 8 minutes.
Minutes are preferred. A photosensitive layer can be provided on the thus obtained support for lithographic printing plate to obtain a photosensitive lithographic printing plate, which is used as a photosensitive lithographic printing plate after plate-making processing.

As the photosensitizer applied to the aluminum plate material of the present invention, a photocrosslinking or photopolymerization type photosensitive composition is used. As the photosensitive composition used as the photosensitive layer, various kinds of materials which have been conventionally used for lithographic printing plate materials can be used. Typical ones will be described below. (1) Photosensitive resin composition A photosensitive resin composition comprising a photosensitive resin having an unsaturated double bond in the molecule, for example, US Pat. Nos. 3,030,208 and 3,435,237.
No. 3,622,320 and a photosensitive group (1) on the polymer main chain.

[0021]

[Chemical 1] Photosensitive resin or polymer containing a side chain of the photosensitive group (1)
There are polyvinyl cinnamate and the like. (2) Photopolymerizable photosensitive composition A composition comprising a monomer having an addition-polymerizable double bond and a binder (polymer compound). Typical compositions are US Pat. Nos. 2,760,863 and 2,791,504. And ibid. 3,801,328
No.

In the present invention, a photopolymerizable composition containing an addition-polymerizable ethylenically unsaturated compound, a binder resin, a sensitizer, and a polymerization initiator is particularly preferable.

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. [Example 1] An aluminum plate having a thickness of 0.3 mm (material 1050,
Conditioned H16) was degreased in a 5% caustic soda aqueous solution at 65 ° C. for 30 seconds, washed with water, immersed in a 10% aqueous nitric acid solution at 25 ° C. for 1 minute, neutralized and washed with water. This aluminum plate was subjected to electrolytic surface roughening in a 2% nitric acid aqueous solution at 30 ° C, an alternating frequency of 50 Hz and a current density of 80 A / dm ² for 15 seconds, and then in a 5% caustic soda aqueous solution at 60 ° C for 5 seconds. Desmut treatment was performed. After that, anodization treatment was performed in a 20% sulfuric acid solution at a temperature of 20 ° C. and a current density of 3 A / dm ² for 1 minute.

Then, it is dipped in a 0.1% aqueous sodium phosphate solution at 80 ° C. for 10 seconds, then dipped in a 1% aqueous sodium silicate solution at 80 ° C. for 30 seconds, and then hot water at 80 ° C. For 30 seconds, then in a 1% aqueous solution of phosphoric acid, 80
After dipping at 20 ° C. for 20 seconds, washing with water, and drying at 80 ° C. for 5 minutes, a support was prepared. A coating solution of a photosensitive composition having the following composition was applied to the obtained support by using a whirler so as to have a dry film thickness of 2 μm, and dried at 70 ° C. for 5 minutes.

[0025]

[Table 1] (Photosensitive composition coating solution composition) Methyl methacrylate / methacrylic acid copolymer 8.2g Trimethylolpropane triacrylate 8.2g Michler's ketone 0.2g Benzophenone 0.8g Dioctylphthalate 0.3g Victoria Pure Blue BOH 0.001g Diethylene glycol dimethyl ether 65 g Further, a polyvinyl alcohol aqueous solution was applied on the surface thereof to form an overcoat layer having a dry film thickness of 3 μm to prepare a photosensitive lithographic printing plate.

On the obtained photosensitive lithographic printing plate, the number of stages is 1
A step tabtet (manufactured by Kodak Co., Ltd.) in which the amount of light attenuates by 1 / √2 each time the number of steps is increased is brought into close contact, and a 1-kW xenon lamp and a glass filter of 350-450 nm that are irradiated from a place 1 m away are irradiated. Light 1
It was exposed for 0 seconds. This plate is then replaced with butyl cellosolve 2
Development was performed with an aqueous solution containing 1 wt% of sodium silicate and 1 wt% of sodium silicate to prepare a photosensitive lithographic printing plate.

The photosensitive lithographic printing plate was filled with an ink for developing ink, and the sensitivity, halftone dot reproducibility and development removability of the photosensitive layer were evaluated as follows. The evaluation results are shown in Table-1.

Sensitivity The step number of the obtained step-cured image was taken as the reading sensitivity. Halftone dot reproducibility The image after development was evaluated by observing the reproducibility of 95% halftone dots.

Development Removability The photosensitive lithographic printing plate was placed on an offset printing machine to determine the occurrence of stains on the non-image area. [Example 2] A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 1 except that the AC frequency at the time of electrolytic surface roughening was 200 Hz. The results are shown in Table 1. [Comparative Example 1] A support subjected to anodization was not treated with an aqueous solution of sodium phosphate, an aqueous solution of sodium silicate and a hot water treatment, except that it was immersed in a 1% aqueous phosphoric acid solution at 80 ° C for 20 seconds and washed with water. A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 1, and the results are shown in Table 1. [Comparative Example 2] The anodized support was not treated with an aqueous solution of phosphoric acid, but was added to a 1% aqueous solution of sodium silicate at 80 ° C and 30 ° C.
A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 1 except that it was dipped for 2 seconds, then treated with hot water at 80 ° C. for 30 seconds, washed with water, and no aqueous phosphoric acid solution was used. Is shown in Table-1. Comparative Example 3 The anodized support was immersed in a 0.1% sodium phosphate aqueous solution at 80 ° C. for 10 seconds and washed with water, and then the sodium silicate aqueous solution treatment, hot water treatment and phosphoric acid aqueous solution were not performed. A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 1 except for the above, and the results are shown in Table 1. [Comparative Example 4] Except that the anodized support was not treated with an aqueous solution of sodium phosphate, an aqueous solution of sodium silicate, and was not treated with hot water, but was immersed in a 1% aqueous solution of phosphoric acid at 80 ° C for 20 seconds and washed with water. A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 2, and the results are shown in Table 1. [Comparative Example 5] The anodized support was not treated with a phosphoric acid aqueous solution, but was added to a 1% sodium silicate aqueous solution at 80 ° C and 30 ° C.
A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 2 except that after dipping for 2 seconds, then treating with hot water at 80 ° C. for 30 seconds, washing with water, and no aqueous phosphoric acid solution, Is shown in Table-1. [Comparative Example 6] The anodized support was immersed in a 0.1% sodium phosphate aqueous solution at 80 ° C for 10 seconds and washed with water, and then the sodium silicate aqueous solution treatment, hot water treatment and phosphoric acid aqueous solution were not performed. A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 2 except for the above, and the results are shown in Table 1.

[0030]

[Table 2]

[0031]

According to the method for producing a photosensitive lithographic printing plate of the present invention, a photosensitive lithographic printing plate excellent in sensitivity, development removability of the non-exposed portion photosensitive layer and adhesion of the exposed portion photosensitive layer is produced. be able to.

Claims (2)

[Claims] 1. An anodized support is treated with (a) an aqueous solution of an alkali metal phosphate, (b) an aqueous solution of an alkali metal silicate and (c) an aqueous solution of phosphoric acid in this order, followed by photocrosslinking or A method for producing a photosensitive lithographic printing plate, which comprises applying a photopolymerizable photosensitive composition. 2. A photosensitive lithographic plate according to claim 1, wherein a support which is electrochemically surface-roughened in an acid electrolyte at a frequency in the range of 150 to 1000 Hz and anodized in a sulfuric acid solution is used. Printing plate manufacturing method.