JPS6356498A - Base for planographic plate - Google Patents

Abstract

PURPOSE:To obtain a planographic plate in which image parts are firmly adhered to a base while a contamination in non-image areas hardly occurs, by providing a hydrophilic layer comprising an alkane having at least two amino groups or a salt thereof on an anodic oxide film on an aluminum plate. CONSTITUTION:A solution of a hydrophilic compound in water or an organic solvent such as methanol is applied to an anodic oxide film provided on an aluminum plate by anodic oxidation, and is dried to provide a hydrophilic layer, whereby a base for a planographic plate can be obtained. The hydrophilic compound comprises an alkane having at least two amino groups or a salt thereof. The alkane includes straight chain, branched and cyclic alkanes. The hydrophilic compound is suitably one which has a molecular weight of up to 1,000. The hydrophilic compound is dissolved in a solvent, e.g., water or an alcohol such as methanol in a concentration of 0.001-10wt% to prepare a coating liquid, and the coating weight is preferably 1-100mg/m<2> on a dry basis. A photosensitive layer is provided on the base for a planographic plate thus obtained, whereby a photosensitive planographic plate is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a support for a lithographic printing plate, and more particularly to a support for a lithographic printing plate comprising an anodized aluminum plate having an improved hydrophilic layer. It is.

[Prior art]

Conventionally, lithographic printing plates include so-called PS plates, which are made by coating a thin layer of a photosensitive composition on an aluminum plate. The surface is roughened by an electrochemical method such as the electrolytic dalein method, or a combination of both methods, and the surface is made into a matte finish.Then, the surface is etched with an aqueous solution of acid or alkali, and then anodized. After that, it is subjected to a hydrophilic treatment if desired to obtain a support for a lithographic printing plate, and a photosensitive layer is provided on this support to form a PS plate (lithographic printing plate).

This PS plate is usually subjected to image exposure, development, correction, and gumming processes to form a lithographic printing plate, which is attached to a printing machine and printed.

However, in the above lithographic printing plate, the positive-acting P
Substances contained in the photosensitive layer irreversibly adsorb to the non-image areas of the lithographic printing plate obtained by imagewise exposure and development of the S plate, contaminating the non-image areas. There have been problems in which it is difficult to identify the image area, and traces of correction remain clearly, resulting in an uneven plate surface, and if the degree of damage becomes severe, it becomes smudged, making it impossible to use it as a printing plate.

To improve this, conventional methods have been used in which the anodized aluminum support surface is immersed in an alkali metal silicate as described in U.S. Pat. No. 3,181,461; .860.426, or British Patent No. 2.098.627.
It has been proposed to apply a treatment such as a sodium arylsulfonate undercoating method as described in the publication, and this prevents the above-mentioned contamination of non-image areas and prevents "stain" from occurring on printed matter. You can do it like this, but
On the other hand, there was a drawback in that the 8'l resistance of the material was reduced to 30 to 80% of that without the above treatment, which was accompanied by a new problem.

In addition, in the case of a negative-working PS plate, the adhesion of the image area of the lithographic printing plate obtained by image exposure and development to the support is reduced;
There was a problem that it could not be used for applications where a large number of sheets were to be printed.

In order to improve this problem, conventional methods have been used in which a thin layer of trihydroxypenzole carboxylic acid is applied to the surface of an anodized aluminum support as described in Japanese Patent Publication No. 44-6410, or Japanese Patent Publication No. 41-1989. Treatments such as the method of providing a thin layer of mellitic acid as described in Japanese Patent Publication No. 14337, or the method of providing a thin layer of phosphonic acid and its derivatives as described in Japanese Patent Publication No. 38-8907. It has been proposed that the adhesion of the above-mentioned image area be improved by this method.
On the other hand, a new problem has arisen in that the stains in the non-image areas are significantly worse than in the case where the above treatment is not performed.

In particular, such problems became more noticeable as time passed after the PS plate was manufactured.

[Purpose of the invention]

An object of the present invention is to provide a support for a lithographic printing plate, which allows obtaining a lithographic printing plate in which the image area is firmly adhered to the support and the non-image area is less likely to be stained.

[Structure of the invention]

The inventors of the present invention have made the present invention as a result of intensive studies to achieve the above object. This is a support for a lithographic printing plate, characterized in that it is provided with a hydrophilic layer made of an alkane having an amino group or a salt thereof. -Hereinafter, the present invention will be explained in detail step by step.

The aluminum plate used in the present invention is a plate-shaped body made of aluminum as a main component, such as pure aluminum or an aluminum alloy containing a trace amount of foreign atoms. These foreign atoms include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The alloy composition has a content of at most 10% by weight or less. Aluminum suitable for the present invention is pure aluminum, but
Since completely pure aluminum is difficult to produce due to smelting technology, it is preferable to use aluminum that contains as few foreign atoms as possible. In addition, if the aluminum alloy has the above-mentioned content,
It can be said that it is a material that can be applied to the present invention. As described above, the composition of the aluminum plate applied to the present invention is not specified; conventionally known and publicly used materials can be used as appropriate. The thickness of the aluminum plate used in the present invention is 0.1 mm to 0.5 mm thick.

Prior to anodizing the aluminum plate, degreasing treatment, such as treatment with a surfactant or alkaline aqueous solution, and graining treatment are carried out, if desired, in order to remove rolling oil from the surface.

Graining treatment methods include a method of mechanically roughening the surface, a method of electrochemically dissolving the surface, and a method of selectively dissolving the surface chemically.Mechanically roughening the surface As the method, known methods such as ball polishing method, brush polishing method, blast polishing method, buff polishing method, etc. can be used.

Further, as an electrochemical surface roughening method, there is a method in which alternating current or direct current is used in a hydrochloric acid or nitric acid electrolyte. Furthermore, a method that combines both methods can also be used, as disclosed in Japanese Patent Application Laid-Open No. 54-63902.

The aluminum plate thus roughened is subjected to alkali etching treatment and neutralization treatment as required.

Any electrolyte that forms a porous oxide film can be used as the electrolyte used in anodizing the aluminum plate, and generally sulfuric acid, phosphoric acid, oxalic acid,
Chromic acid or a mixed acid thereof is used, and the concentration of the electrolyte is determined as appropriate depending on the type of electrolyte.

The treatment conditions for anodic oxidation vary depending on the electrolyte used, so they cannot be specified definitively, but generally the electrolyte concentration is 1.
~80% by weight solution, liquid temperature 5~70℃, current density 5~6
0A/dm', voltage 1~100■ Electrolysis time 10 seconds~50
It is appropriate if it is within the range of minutes.

The amount of the anodic oxide film is preferably from 0.1 to 10 g/m', more preferably from 1 to 6 g/m'. A solution of the hydrophilic compound described below dissolved in water or an organic solvent such as methanol is coated on the anodized film of the aluminum plate treated as described above, and dried to form a hydrophilic layer. .

A support for a printing plate is obtained. The hydrophilic compound used in the present invention consists of an alkane or a salt thereof having at least two amine groups.

The alkanes mentioned above include straight chain, branched, and cyclic alkanes. Particularly preferred are those represented by the following general formula.

NH2-(CH2)r, -NH2 (n represents an integer of 2 to 10) The hydrophilic compound used in the present invention is preferably a compound having a molecular weight of 1,000 or less. Specific hydrophilic compounds include ethylenediamine, 1゜3-diaminopropane, 1,4-diaminobutane, 1,2-diaminopropane, 1,2-diamino-2-methylpropane, 1,5-diaminopene. Kun, 1,6-diamithexane, 1,7-
Diaminohebutane, 1,2-diaminocyclohexane,
1.8-diaminooctane, 1.9-diaminononane,
1.10-diaminodecane or its hydrochloride, oxalate, phosphate, phosphite, sulfate, nitrate, etc.

Among these, 1,5-diaminopencune, 1,6-
Diamithexane is most preferred.

Hydrophilic compounds as described above can be prepared in a suitable solvent such as water,
0.001-10% by weight in alcohol such as methanol
It is dissolved at a concentration of and used as a coating solution.

At this time, it is appropriate that the pH after coating is in the range of 1 to 13. Further, the temperature of the coating liquid is suitably in the range of 10 to 50°C.

As the coating method, any method such as dip coating, spin coating, spray coating, curtain coating, etc. may be used. The coating amount after drying is preferably from 1 to 100 mg/m', more preferably from 5 to 50 mg/m'. As the above coating amount becomes less than 1 mg/m', The effect of preventing stains on the image area gradually disappears, and on the other hand, as the amount exceeds 100 mg/m'', the adhesion between the photosensitive layer and the support deteriorates, and only a lithographic printing plate with low printing durability can be obtained.

Before or after providing such a hydrophilic layer, the anodized aluminum plate can be treated with an aqueous solution of an alkali metal silicate (e.g. sodium silicate) as described in U.S. Pat. No. 3,181,461. can.

On the lithographic printing plate support obtained in this way,
A photosensitive lithographic printing plate can be obtained by providing a conventionally known photosensitive layer as a photosensitive layer of a PS plate (abbreviation for Pre-3 sensitized plate), and a lithographic printing plate obtained by platemaking processing of this plate is , has excellent performance.

As the composition for the above-mentioned photosensitive layer, any composition can be used as long as its solubility or swelling property in a developer changes before and after exposure. The typical ones will be explained below.

■ As a positive-acting photosensitive diazo compound,
Benzoquinone described in Publication No. 3-28403
Most preferred are esters of 1,2-diazide sulfonic acid chloride and polyhydroxyphenyl or esters of naphthoquinone-1,2-diazide sulfonic acid chloride and pyrogallol-acetone resin. Other comparatively suitable 0-quinonediazide compounds include benzoquinone-1,2-
Diazide sulfonic acid chloride or naphthoquinone-1゜2
- There are esters of diazide sulfonic acid chloride and phenol formaldehyde resin. The 〇-quinonediazide compound constitutes the photosensitive layer by itself, but it is used together with this type of resin using a resin soluble in alkaline water as a binder. The resin soluble in this alkaline water is
There are novolac resins having this property, such as phenol formaldehyde resin, cresol formaldehyde resin, pt-butylphenol-formaldehyde resin, phenol-modified xylene resin, and phenol-modified xylene/mesitylene resin. Other useful alkaline water-soluble resins include polyhydroxystyrene;
Mention may be made of copolymers of polyhalogenated hydroxystyrenated (meth)acrylic acids and other vinyl compounds.

Further details of the photosensitive layer consisting of an 0-quinonediazide compound and its developer are detailed in U.S. Pat. No. 4,259,434.

■A photosensitive composition consisting of a diazo resin and a binder.

As a negative-acting photosensitive diazo compound, US Patent No. 2.
Diphenylamine, which is a reaction product of the diazonium salt disclosed in No. 063.631 and No. 2.667 and No. 415, and an organic condensing agent containing a reactive carbonyl group such as aldol or acecool. A condensation product of p-diazonium salt and formaldehyde (so-called photosensitive diazo resin) is preferably used. Other useful fused diazo compounds are U.S. Pat. No. 3.679.419, British Pat.
It is disclosed in each specification of No. 26. These types of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts,
Therefore, it can be applied from an aqueous solution.

In addition, these water-soluble diazo compounds are disclosed in British Patent Nos. 1 and 28.
0.885 with an aromatic or aliphatic compound having one or more phenolic hydroxyl groups, sulfonic acid groups, or both; A water-insoluble photosensitive diazo resin can also be used.

It can also be used as a reaction product with hexafluorophosphate or tetrafluoroborate as described in JP-A-56-121031.

In addition, diazo resins described in British Patent No. 1.312.925 are also preferred.

Such diazo resins are used together with binders. Preferred binders are organic polymers having an acid value of 10 to 200, and specific examples include copolymers containing acrylic acid, methacrylic acid, crotonic acid, or maleic acid as an essential polymerization component, such as U.S. Pat. .123
．． 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, acrylonitrile or methacrylate trile, acrylic acid or methacrylic acid and optionally further copolymerizable monomers as described in No. 276. Original copolymer, acrylic acid or methacrylic acid, acrylic acid or methacrylic acid, which has a hydroxyl group at the end and is esterified with a group containing a dicarboxylic acid ester residue, as described in JP-A-53-120903. Copolymer with acid and, if necessary, other copolymerizable monomers, JP-A-5
A monomer having an aromatic hydroxyl group at the end as described in No. 4-98614 (for example, N-(4-hydroxyphenyl) methacrylamide, etc.), acrylic acid or methacrylic acid, and further as necessary. Copolymer with at least one other copolymerizable monomer, JP-A-56-
Copolymers of alkyl acrylates or methacrylates, acrylonitrile or methacrylate linope, and unsaturated carboxylic acids as described in No. 4144 are included. Also acidic polyvinyl alcohol derivatives,
Acidic cellulose derivatives are also useful.

■ A composition consisting of a polymer compound containing -CH=CH-C- groups in the main chain or side chain of the polymer -CH=CH- as a photosensitive group in the main chain or side chain of the polymer
Those whose main component is a photosensitive polymer such as C-containing polyesters, polyamides, and polycarbonates (for example, U.S. Pat. No. 3.030.208, U.S. Pat. No. 3.707)
．． 373 and 3,453, 237) derived from (2-probelidene) malonic acid compounds such as cinnamylidene malonic acid and difunctional glycols Those mainly composed of photosensitive polyesters (for example, U.S. Patent No. 2.956°87)
8 and 3.173.787); cinnamate esters of hydroxyl-containing polymers such as starch, cellulose and their analogs to polyvinyl alcohol; (e.g. U.S. Pat. No. 2.6)
No. 90.966, No. 2,752, 372, No. 2.
Description agents, plasticizers, pigments, dyes, etc. can be included in each specification such as the old No. 732.3.

■ So-called photopolymerizable compositions that cause a polymerization reaction when irradiated with active light. For example, composition 1 comprising an addition polymerizable unsaturated compound having two or more terminal ethylene groups and a photopolymerization initiator as described in U.S. Pat. Of course.

The compound that trimerizes and the compound that undergoes a polymerization reaction upon irradiation with actinic rays may further contain a resin as a binder, a sensitizer, a thermal polymerization inhibitor, a dye, a plasticizer, and the like.

The photosensitive composition as described above is usually applied as a solution of water, an organic solvent, or a mixture thereof onto a support according to the present invention and dried to prepare a photosensitive lithographic printing plate.

The coating amount of the photosensitive composition is generally 0.1 to about 5.0
g/m' is suitable, about 0.5 to about 3.0 g/m+
is more preferable.

The photosensitive lithographic printing plate thus obtained is imagewise exposed using a light source containing actinic rays such as a carbon arc lamp, xenon lamp, mercury lamp, tungsten lamp, metal halide lamp, etc., and developed to obtain a lithographic printing plate.

〔Effect of the invention〕

A lithographic printing plate using an aluminum support obtained according to the present invention has a remarkable effect that it has higher printing durability than conventional plates and at the same time, non-image areas are less likely to be stained. Conventionally, lithographic printing plates with high printing durability tend to smear in non-image areas, while lithographic printing plates with less smearing in non-image areas have low printing durability.We have developed a new technology that improves both of these properties at the same time. It was considered extremely difficult to do so.

However, the lithographic printing plate using the aluminum support according to the present invention has excellent properties not previously available, such as high printing durability and resistance to staining of non-image areas.

〔Example〕

Hereinafter, the present invention will be explained in more detail using Examples. Note that "%" in the examples indicates "% by weight" unless otherwise specified.

Example I JIS 1050 aluminum sheet with pamice water g5
Using the liquid as an abrasive, the surface was grained with a rotating nylon brush. At this time, the surface roughness (center line average roughness) is 0.
It was 5μ. After washing with water, add 10% caustic soda solution to 70%
It was etched by immersing it in a solution heated to 0.degree. C. so that the amount of aluminum dissolved was 6 g/m'. After washing with water, 30%
It was immersed in a nitric acid aqueous solution for 1 minute to neutralize it, and then thoroughly washed with water. Thereafter, in a 0.7% nitric acid aqueous solution, a rectangular alternating waveform with an anode voltage of 13 volts and a cathode voltage of 6 volts was used (the power supply waveform described in the example of JP-A-52-77702). Electrolytic surface treatment was performed for 20 seconds, and 50% of 20% sulfuric acid was applied.
After cleaning the surface by immersing it in a solution at ℃, it was washed with water.

Furthermore, the weight of the anodic oxide film was 3.0 in a 20% sulfuric acid aqueous solution.
A substrate (I) was prepared after performing anodization using direct current to give an anodic oxidation treatment of 1.5 g/m'', washing with water, and drying.

A solution (A) having the following composition was applied to the surface of the substrate (I) thus treated and dried at 80° C. for 30 seconds.

The coverage after drying was 10 mg/m'.

In this way, a substrate (II) was created.

Also, instead of 1,5-diaminopenkune, 1.6--
A solution having the following composition was applied to the substrate (I) using diaminohexane and dried at 80° C. for 30 seconds. Coverage amount is 1 after drying
It was 0 mg/m'.

In this way, a substrate (III) was created.

Furthermore, for comparison, carboxymethyl cellulose (molecular ff 125.000) or polyvinyl alcohol (molecular i 10.000) was dissolved in water and applied onto the substrate (I) so that the coating amount after drying was 10 mg/m'. A substrate (■) and a substrate (V) were respectively provided.

A photosensitive layer was provided on the substrates (I) to (V) thus prepared such that the following composition had a coating weight of 2.5 g/m' after drying.

[Naphthoquinone-1,2-diazide-5-sul] The photosensitive lithographic printing plate thus prepared was exposed to 3 k from a distance of 1 m through a transparent positive film in a vacuum printing frame.
After exposure for 50 seconds using a W metal halide lamp, a 5.26% aqueous solution of sodium silicate with a Sho□/Na2Q molar ratio of 1.74 was added (pH = 1).
2.7).

After developing in this manner, the film was thoroughly washed with water and gummed, and then printed using a conventional procedure. Table 1 shows the results of examining the staining of the non-image area and printing durability at this time.

From the results in Table 1, it can be seen that the supports according to the present invention are more satisfactory in both printing durability and staining in non-image areas than those of the comparative examples.

Table 1 △D = (Non-image area density after development) - (Support density before coating) ○ ...... △D = 0.03 or less △ ...
・・・Thicker than 0.03 and 0.05 or less× ・・・・
...From △D=0.05, the Commissioner of the Patent Office Black 1) Mr. Hu Xiong 1. (Indication of 1986 Patent Application No. 20040)
No. 2 2, Title of the invention Support for lithographic printing plate 3,
? Relationship to the i-correction case Applicant name (520) Fuji Photo Film Co., Ltd. 4;
Agent 5, Date of amendment order Proprietor 6, Subject of amendment Detailed explanation of the invention in the specification column 7, ? rti positive content

Claims (3)

[Claims] (1) A support for a lithographic printing plate, comprising an aluminum plate having an anodized film, and a hydrophilic layer made of an alkane or a salt thereof having at least two amino groups provided on the film. (2) The support for a lithographic printing plate according to claim 1, wherein the compound has a molecular weight of 1000 or less. (3) The support for a lithographic printing plate according to claim 1, wherein the coating amount of the hydrophilic layer is 1 to 100 mg/m^2.