JPS6219494A - Base material for lithographic printing - Google Patents

Abstract

PURPOSE:To obtain the lithographic printing plate in which the picture part is strongly sticked to the base material, further the ink adhered to the non- picture part being quickly removed and contamination is difficult to be generated in the non-picture part, by providing the hydrophylic layer containing phosphate on the film of the aluminum plate having an anodic oxidation film. CONSTITUTION:It is the base material for lithographic printing plate in which the hydrophylic layer containing phosphate is established on the anodic oxidation film of the aluminum plate having said film. Preferable phosphates to be used are the metal salts or ammonium salts of Ia, IIa, IIb, IIIb, VIIa or VIII groups. They are concretely the salts of NH4, Li, Be, B, Na, Ba, etc. or the salt containing not less than 2 kinds of those constituents. Especially, those of 1,000 max. in molecular weight should be preferable. If the molecular weight exceeds 1,000, the layer becomes undesirably easy to be peeled. Though there are the primary, the secondary, the tertiary phosphate, etc. as preferable hydrophylic phosphate, the especially preferable one is the primary phosphate such as KH2PO4, NaH2PO4 and NH4H2PO4.

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 made of an aluminum plate having an improved hydrophilic layer on an anodized film. It is something.

[Prior art]

Conventionally, lithographic printing plates include so-called PS plates in which a photosensitive composition is coated in a thin layer 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, and then etched with an aqueous solution such as an acid or alkali. After further anodic acid treatment, a hydrophilic treatment is applied as desired to form a support for a lithographic printing plate1, and a photosensitive layer is provided on this support to form a PS plate (lithographic printing plate). Ru. □This PS plate is usually subjected to image exposure, development, correction, and gumming □pulling processes to make a lithographic printing plate, which is attached to a printing □ machine and printed.

However, in the above-mentioned lithographic printing plate, substances contained in the photosensitive layer irreversibly adsorb to the non-image area of the lithographic printing plate obtained by imagewise exposure and development, contaminating the non-image area. It is difficult to distinguish between the image area and the non-image area, or the plate surface becomes uneven with clear traces of correction, and if this becomes severe, it becomes smudged and cannot be used as a printing plate (
There was a problem.

In order to improve this, a conventional method has been used in which the anodized aluminum support surface is immersed in an alkali metal silicate as described in US Pat. No. 3,181,461. 860.426, or British Patent No. 2.098.62.
A treatment such as a method of undercoating with AJ+sodium sulfonate as described in No. 7 is applied. By performing such processing, it is possible to prevent the above-mentioned contamination of the non-image area and prevent "stains" from occurring on the printed matter, but on the other hand, the printing durability of the printed matter may be reduced if the above treatment is not applied The disadvantage was that it was accompanied by a new problem: a reduction of 50 to 80% of the case.

In addition, conventional methods include providing a thin layer of trihydroxybenz'-carboxylic acid on the surface of an anodized aluminum support as described in Japanese Patent Publication No. 44-6410, or Japanese Patent Publication No. 41-14337. By applying a treatment such as a method of providing a thin layer of mellitic acid as described in Japanese Patent Publication No. 3B-8907, or a method of providing a thin layer of phosphonic acid and its derivatives as described in Japanese Patent Publication No. 3B-8907. Attempts have been made to improve the adhesion of the image area, but on the other hand, a new problem has arisen in that the staining of the non-image area is significantly worse than when the above-mentioned treatment is not performed. Particularly after producing the 28th edition, such problems tended to become more noticeable as time passed.

Furthermore, conventional planographic printing plates have the problem that ink adhering to non-image areas is not quickly removed, resulting in stains.

In this way, it has traditionally been the case that lithographic printing plates with high printing durability are prone to staining in non-image areas, and conversely, lithographic printing plates that are hard to stain in non-image areas have low printing durability. It was believed that it would be extremely difficult to make improvements at the same time.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a lithographic printing plate in which the image area is firmly adhered to the support, and ink adhering to the non-image area is quickly removed, and the non-image area is less likely to be contaminated. An object of the present invention is to provide a support for a lithographic printing plate.

[Structure of the invention]

The present inventors have made extensive studies to achieve the above object, and as a result, have completed the present invention. The present invention is a support for a lithographic printing plate, characterized in that a hydrophilic layer containing a phosphate is provided on an aluminum plate having an anodized film. Preferred phosphates used in the present invention are Ia of the periodic table,
IIa, IIb.

■b1■a or group ■ metal salt, or ammonium salt.

Specifically, NH4, Li, Be5B, Na.

Mg, AI! , KS CaX Mn, Fe, Co, Ni
.

It is a salt such as ZnSSr or Ba, or a salt containing two or more of these.

Particularly preferred are those having a molecular weight of 1000 or less.

When the molecular weight exceeds 1000, layer peeling tends to occur, which is not preferable. Specific examples of preferable hydrophilic phosphates include NH, 112PO,, (N)14)211P[1,
,K112PO,,K,1IPO,,ZnHPO-1N
H, Na1lP04, NH, KIIPO,, N114C
aPO4, A I (LPL) 3, A I! , (H
PO, ), , MnHPO4, Mn (H2PO,)2,
Mn1la (PO-)2, C03(PO4)2, B
a(H2PO,)2, Ba11P04, Li)! zP0
4, LI2HP mouth 4, Bez(P[1s)2,
Bl'04, N1a(PD<)z, Mg, 3(PD
<)z, FeHP[]4, Fe3 (PO4)2, S
Examples include primary, secondary and tertiary phosphates such as r(l12P[+->2.5rllP04, etc.) Among these, particularly preferred are Kl(2P[1,, NaHaPO
, , NH, H2PO4.

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 pure aluminum containing aluminum as a main component or an aluminum alloy containing a trace amount of foreign atoms.

Such foreign atoms include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of these foreign atoms is generally 10% by weight or less. Aluminum suitable for the support of the present invention is pure aluminum, but since it is difficult to produce completely pure aluminum due to smelting technology, it is preferable to use aluminum that contains as few foreign atoms as possible. 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 appropriate thickness of the aluminum plate used in the present invention is approximately 0.1 mm to 0.5 mm.

Prior to anodizing the aluminum plate, degreasing treatment using, for example, a surfactant or an 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. As a method for mechanically roughening the surface, known methods such as ball polishing, brush polishing, blast polishing, puff polishing, 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.

Sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used as the electrolyte for anodizing the aluminum plate, and the electrolyte and its concentration are 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/dm2, voltage 1~100■, electrolysis time 10 seconds~5
A range of 0 minutes is appropriate.

The amount of the anodic oxide film is preferably in the range of 0.1 to 10 g/m2, but more preferably in the range of 1 to 6 g/m2. Alternatively, the lithographic printing plate support of the present invention can be obtained by dissolving a solution of the phosphate in an organic solvent such as methanol and drying it to form a hydrophilic layer.

The appropriate concentration of phosphate in the coating solution is 0.001 to 10% by weight. At this time, the pH of the coating liquid is preferably in the range of 1 to 13. Also, the temperature of the coating liquid is 10 to 50℃
A range of is appropriate.

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/m2, more preferably from 5 to 50 mg/m2. If the above-mentioned coating amount is less than 1 mg 7 m2, the effect of preventing stains in the non-image area is lost and it becomes difficult to remove the ink adhering to the non-image area. the other 100
When the amount exceeds mg/m2, 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.

A conventionally known photosensitive layer can be provided on the lithographic printing plate support thus obtained to obtain a photosensitive lithographic printing plate. The plate 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 7-toquinone-1.2
- There are esters of diazide sulfonic acid chloride and phenol formaldehyde resin.

The 0-quinonediazide compound alone constitutes the photosensitive layer, but a resin soluble in alkaline water may be used in combination as a binder. Examples of resins soluble in alkaline water include novolac resins, such as phenol formaldehyde resin, cresol formaldehyde resin,
Examples include pt-butylphenol formaldehyde resin, phenol-modified xylene resin, and phenol-modified xylene/mesitylene resin. Other useful alkaline water-soluble resins include polyhydroxystyrene, copolymers of polyhalogenated hydroxystyrenated (meth)acrylic acid and other vinyl compounds.

Further details of photosensitive layers consisting of 0-quinonediazide compounds and their developers are described 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 is a reaction product of the diazonium salt disclosed in No. 063.631 and No. 2.667, 415 and an organic condensing agent containing a reactive carbonyl group such as aldol or acetal. 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. Alternatively, these water-soluble diazo compounds can be converted into aromatic or aliphatic compounds having one or more phenolic hydroxyl groups, sulfonic acid groups, or both by the method disclosed in British Patent No. 1.280.885. It is also possible to use a substantially water-insoluble photosensitive diazo resin which is a reaction product of the reaction.

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 US Pat. 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 Copolymers of methacrylic acid and, if necessary, other copolymerizable monomers, monomers having an aromatic hydroxyl group at the end as described in JP-A No. 54-98614 (e.g. N-(4-hydroxyphenyl) methacrylamide, etc.), acrylic acid or methacrylic acid, and if necessary, a copolymer with at least one other copolymerizable monomer, as described in JP-A-56-4144. Included are copolymers of alkyl acrylates or methacrylates, acrylonitrile or methacrylatetrile, and unsaturated carboxylic acids as described. Also useful are acidic polyvinyl alcohol derivatives and acidic cellulose derivatives.

■ A composition containing a compound that causes two-layer formation upon irradiation with actinic rays. For example, polyvinyl cinnamate, polyvinyl cinnamoyl ethyl ether, polyethylene cinnamate acrylate and its copolymers, polyethyl cinnamate methacrylate and its copolymers, polyparavinylphenyl cinnamate and its copolymers, polyvinyl benzal acetophenone and its derivatives, polyvinyl cinnamylidene acetate and its derivatives, allyl acrylate prepolymer and its derivatives, derivatives of polyester resins consisting of paraphenylene diacrylic acid and polyhydric alcohol, such as U.S. Pat. No. 3.030.208. These include compounds as described in the specification.

■ A so-called copolymerizable composition that causes a polymerization reaction when irradiated with active light. For example, compositions comprising an addition polymerizable unsaturated compound having two or more terminal ethylene groups and a photopolymerization initiator as described in U.S. Pat. There is.

The compound that forms two layers 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 the support according to the present invention, and dried to prepare a photosensitive lithographic printing plate.

The coating amount of the photosensitive composition is generally about 0.1 to about 5.0
g 7m2 is suitable, about 0.5 to about 3.0g/m
' is more preferable.

The photosensitivity-plate printing plate thus obtained is imagewise exposed with a light source containing actinic rays such as a carbon arc lamp, a Cannon lamp, a mercury lamp, a tungsten lamp, a 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 excellent properties not previously available, such as providing higher stiffness resistance than conventional plates and at the same time being resistant to staining in 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 The surface of a JIS1050 aluminum sheet was grained with a rotating nylon brush using a vamisu water suspension as an abrasive. At this time, the surface roughness (center line average roughness) is 0.5
It was μ. After washing with water, add 10% caustic soda aqueous solution to 70°C.
The amount of aluminum dissolved is 6.
g It was etched to a size of 7m2. After washing with water, 3
It was immersed in a 0% nitric acid aqueous solution for 1 minute to neutralize it, and then thoroughly washed with water. After that, in a 0.7% nitric acid aqueous solution, an anode special voltage of 13
Electrolytic surface treatment was carried out for 20 seconds using a rectangular alternating waveform with a cathode special voltage of 6 volts (power supply waveform described in the example of JP-A-52-77702), and a solution of 20% sulfuric acid at 50°C. After washing the surface by immersing it in water, 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 (1) was prepared after anodizing using a direct current so as to obtain a coating film of 1.5 g/m'', washing with water, and drying.

A solution (1) having the following composition was applied to the surface of the substrate (1) thus treated and dried at 80° C. for 30 seconds □.

The coating density after drying was 10 mg/m2.

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

Also, on the substrate (1), 1'7 of monoammonium phosphate
．． Wow, Jl, IE-IJ7 Yaka, Tsu,, ya□Ieko8,
picture. 1 solution (n) was applied and dried at 80° C. for 30 seconds. -,1 coating amount was 10 mg/m' after drying.

In this way, the group 1ffl(III) was created.

For further comparison, carboxymethyl, cellulose (125,000 molecules) or polyvinyl alcohol (1 molecule
11Q.

The following composition was coated on the substrates (1) to (■) thus prepared so that the coating weight after drying was 2.5 g/m<2> to provide a photosensitive layer.

The photosensitive planographic printing plate thus produced was exposed in a vacuum printing frame through a transparent positive film from a distance of 1 m using a 3KW metal halide lamp for 50 seconds, and then exposed to SiO□/Na,O. molar ratio is 1.7
4) 5.26% aqueous solution of IJium (pH=
12.7).

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.

Example 2 The surface of a JIS1050 aluminum sheet was grained using a rotating nylon brush using a pumice water suspension as an abrasive. At this time, the surface roughness (center line average roughness) is 0.5
It was μ. After washing with water, add 10% caustic soda aqueous solution to 70°C.
It was etched by immersing it in a solution warmed to a temperature such that the amount of aluminum dissolved was 6 g 7 m2. After washing with water,
It was immersed in a 30% nitric acid aqueous solution for 1 minute to neutralize it, and then thoroughly washed with water. After that, in a 0.7% nitric acid aqueous solution, the anode special voltage 1
Electrolytic surface treatment was carried out for 20 seconds using a rectangular alternating waveform of 3 volts and a cathode special voltage of 6 volts (power supply waveform described in the example of JP-A-52-77702), and 20% sulfuric acid was heated at 50°C. After washing the surface by immersing it in a solution, it was washed with water.

Furthermore, the weight of the anodized film was 1.5 in a 20% sulfuric acid aqueous solution.
After anodic oxidation using direct current so that the size of the support was 7 m2, it was washed with water, immersed in a 2% aqueous sodium silicate solution at 70°C for 1 minute, washed with water, and dried to prepare a support (VI).

The solution (1) used in Example 1 was applied to the surface of the thus treated substrate (■) and dried at 80° C. for 30 seconds.

The coating amount after drying was 10 mg/m'.

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

Further, the solution (II) used in Example 1 was applied to the substrate (VI) and dried at 80° C. for 30 seconds.

The coating amount was 10 mg/m2 after drying.

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

Furthermore, for comparison, carboxymethyl cellulose (molecular weight 25,000) or polyvinyl alcohol (molecular weight 1
0.000) was dissolved in water and provided on the substrate (VI) so that the coating amount after drying was 10 mg/m2 to create a substrate (■) and a substrate (X), respectively. .

A photosensitive layer was provided on the substrates (Vl) to (X) thus prepared by applying the following composition so that the coating weight after drying was 2.5 g and 7 m<2>.

Photosensitive solution The photosensitive lithographic printing plate thus prepared was exposed in a vacuum printing frame through a transparent negative film from a distance of 1 m for 50 seconds using a 3KW metal halide lamp, and then exposed to light using a developer having the following composition. It was developed and gummed with an aqueous gum arabic solution to prepare a lithographic printing plate.

Developer The printing plate made in this manner was printed in the usual manner.

The results of checking the stains and printing durability of the non-image area at this time are shown in the second section.
Shown in the table.

From the results in Table 2, it can be seen that the support according to the present invention is more satisfactory in both stiffness resistance and staining in non-image areas than the support of the comparative example.

Claims (4)

[Claims] (1) A support for a lithographic printing plate, characterized in that a hydrophilic layer containing a phosphate is provided on an aluminum plate having an anodized film. (2) Phosphate is Ia, IIa, IIb, IIIb on the periodic table,
The support for a lithographic printing plate according to claim 1, which is a salt of a group VIIa or VIII metal, or an ammonium salt. (3) The support for a lithographic printing plate according to claim (1), wherein the phosphate has a molecular weight of 1000 or less. (4) 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.