JPH0635215B2 - Method for producing support for lithographic printing plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lithographic printing plate support, and more particularly to a lithographic printing plate support comprising an anodized aluminum plate having an improved hydrophilic layer. It is about the body.

[Conventional technology]

Conventionally, a lithographic printing plate includes a so-called PS plate in which a photosensitive composition is applied in a thin layer on an aluminum plate, but the above-mentioned aluminum plate is usually a mechanical method such as a brush grain method or a ball grain method or It is subjected to a roughening treatment such as an electrochemical method such as an electrolytic grain method or a method combining both methods, and after the surface is made satin-finished, it is etched with an aqueous solution of acid or alkali, and further anodized. After that, it is subjected to a hydrophilic treatment as desired to obtain a lithographic printing plate support, and a PS layer (photosensitive lithographic printing plate) is obtained by providing a photosensitive layer on the support. This PS
The plate is usually subjected to image exposure, development, correction and gumming process to obtain a lithographic printing plate, which is attached to a printing machine for printing.

However, in the above lithographic printing plate, the positive action P
Substances contained in the photosensitive layer are irreversibly adsorbed to the non-image area of the lithographic printing plate obtained by imagewise exposing and developing the S plate, and contaminate the non-image area. There is a problem that it is difficult to identify the image portion, or the correction marks are clearly left and the plate surface becomes uneven, and when the degree of the correction becomes severe, it becomes dirty and cannot be used as a printing plate.

To improve this, a method of immersing the anodized aluminum support surface in an alkali metal silicate as described in U.S. Pat.No. 3,181,461, described in U.S. Pat.No. 3,860,426. Like,
Undercoating methods of hydrophilic cellulose containing a water-soluble metal salt, or undercoating method of sodium arylsulfonate as described in British Patent 2,098,627 have been proposed. By carrying out such a treatment, it is possible to prevent the above-mentioned contamination of the non-image portion and prevent "smudge" from occurring in the printed matter, but on the other hand, the printing durability of the printed matter is not subjected to the above treatment. There was a drawback with a new problem of reduction to 30-80% of the case.

Further, in order to improve the above-mentioned defects caused by the presence of an anodized film, JP-A-54-128453 and JP-A-55-
Japanese Patent No. 28400 discloses a method of significantly increasing the aluminum ion concentration in the electrolytic solution forming the anodized film to 10 to 25 g / m or anodic oxidation in a mixed electrolytic solution of sulfuric acid and phosphoric acid. . However, in this method, scale is likely to occur, sludge (Al (OH) ₃ ) in the waste liquid treatment is increased, and it takes a great deal of effort to control the acid concentration of both sulfuric acid and phosphoric acid, resulting in poor manufacturability. There was a drawback. When anodizing at a higher current density,
In some cases, a non-uniform anodic oxide film called "burn" was formed in which the film grew remarkably.

Further, since the acid concentration in the electrolytic solution is low, the porosity of the formed anodic oxide film is remarkably reduced, which results in insufficient adhesion to the photosensitive layer and reduced printing durability to 80 to 90%. .

The present inventors have proposed a method for solving the above-mentioned problems in Japanese Patent Application No. 61-120.
Proposed in 675. That is, in the method for producing a lithographic printing plate support, an anodizing treatment is performed, a hydrophilizing treatment with a metal silicate is then performed, and then the treatment is performed with steam or water at 60 to 100 ° C. or a dilute alkaline solution at 60 to 100 ° C. is there.

It has been known that this base treatment leaves the hydrophilic characteristics of the metal silicate and enhances the adhesion. However, the printing durability varies greatly depending on the printing conditions, and there is a drawback that the printing durability is inferior to that of a substrate not subjected to a hydrophilic treatment with a metal silicate. Further, as a method of applying a hydrophilizing substance to the surface, JP-A-53-109705 proposes to provide a hydrophilic intermediate layer before forming an anodized film, but in this method,
The formation of the hydrophilic layer on the surface is insufficient, and the printing durability tends to be slightly inferior.

[Object of the Invention]

An object of the present invention is to provide a support for a lithographic printing plate which does not deteriorate printing durability and is less likely to stain the non-image area.

[Structure of Invention]

As a result of intensive studies to achieve the above-mentioned object, the present inventors have reached the present invention, that is, the present invention, after graining an aluminum plate, at least one of the surfaces. A method for producing a lithographic printing plate support is characterized in that a hydrate of aluminum is formed, a surface thereof is subjected to a silicate treatment, and then an anodization treatment is performed.

Hereinafter, the present invention will be described in detail step by step.

The aluminum plate used in the present invention is a plate-shaped body such as pure aluminum containing aluminum as a main component or an aluminum alloy containing a slight amount of foreign atoms. This foreign atom is
It is silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, titanium, etc., and the alloy composition has a content of at most 10% by weight.
The aluminum suitable for the present invention is pure aluminum, but completely pure aluminum is difficult to produce due to the kneading technique, and therefore it is preferable that it contains no foreign atoms as much as possible. Further, the aluminum alloy having the above content rate can be regarded as a material applicable to the present invention.

As described above, the aluminum plate applied to the present invention is not specified in its composition, and conventionally known and officially used materials can be appropriately used.

The thickness of the aluminum plate used in the present invention is about 0.
It is about 1 mm to 0.5 mm. Prior to the graining treatment, a degreasing treatment with a surfactant or an alkaline aqueous solution is carried out, if desired, in order to remove the rolling oil on the surface of the aluminum plate. After that, the aluminum plate is subjected to a graining treatment.

The graining treatment method includes a method of mechanically roughening the surface, a method of electrochemically melting the surface, and a method of chemically selectively melting the surface. As a method for mechanically roughening the surface, a known method called a ball polishing method, a brush polishing method, a blast polishing method, a buff polishing method or the like can be used. Further, as an electrochemical surface-roughening method, there is a method of carrying out alternating current or direct current in a hydrochloric acid or nitric acid electrolyte. Further, as disclosed in Japanese Patent Application Laid-Open No. 54-63902, a method in which both are combined can be used.

The aluminum plate thus roughened is subjected to alkali etching treatment and neutralization treatment, if necessary.

After that, a treatment for forming a hydrate of aluminum, which is a feature of the present invention, is performed. This hydrate formation can be carried out by steam, water at 60 to 100 ° C, or dilute alkaline solution immersion at 60 to 100 ° C.
Treatment with water at ° C is preferred. By these treatments, a hydrate of aluminum (boehmite or bayerite) is formed on the surface of aluminum, thereby enhancing the effect of the hydrophilization treatment by silicate (increasing the adsorption amount), and further performing the anode. By the oxidation treatment, a lithographic printing plate support having a surface capable of forming a strong adhesion with the image area can be obtained. When the treatment with steam is performed, the temperature is preferably 100 to 120 ° C. The dilute alkaline solution preferably has a pH in the range of 7.5 to 12.5, and any alkaline agent may be used as long as it has this pH range. Typical alkali agents include M (OH) _n , M (CO ₃ ) _n , M (CO ₃ CO ₃
O) _n , M (BO ₃ ) _n , hydroxide represented by the general formula of Mm (PO ₃ ),
Carbonate, acetate, etc. are used (where M represents ammonia, alkali metal and alkaline earth metal.
And m is an integer of 1 to 3).

Also, an alkaline organic acid salt such as sodium gluconate, sodium tartrate, potassium tartrate or the like can be used, and an organic amine such as ethanolamine can also be used.

In the case of treatment with water or a dilute alkaline solution, if the treatment liquid temperature is lower than 60 ° C., a sufficient effect cannot be obtained even after long-term treatment, and only a printing plate having low printing durability can be obtained. Therefore,
The treatment temperature is 60 to 100 ° C., and a slightly lower temperature when using a dilute alkaline aqueous solution, that is, 60 to 80 ° C.
C is preferred.

On the other hand, the treatment time is 60 to 100
In any case of treatment with water at 60 ° C. or a dilute alkaline aqueous solution at 60 to 100 ° C., 10 seconds or more is appropriate, and 10 seconds to 2 minutes is particularly preferable.

After forming a hydrate of aluminum by such a treatment, as described in U.S. Pat.Nos. 2,714,066 and 3,181,461, alkali metal silicates, for example, silicates by a dipping method with sodium silicate. A layer is formed or an alkaline earth metal silicate treatment described in JP-A-60-194095 is performed.

The aluminum plate is then subjected to anodizing treatment. As the electrolyte used for the anodizing treatment, any one that forms a porous oxide film can be used, and generally sulfuric acid, phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of is appropriately determined depending on the type of electrolyte. The treatment conditions for anodic oxidation cannot be unconditionally specified because they vary depending on the electrolyte used, but generally the temperature of the electrolyte is 1 to 80% by weight solution, and the liquid temperature is 5 to 5.
70 ℃, current density 5-60Å / dm ² , voltage 1-100V
It is appropriate that the electrolysis time is in the range of 10 seconds to 50 minutes.

The amount of the anodized film is preferably 0.1 to 10 g / m ² , but more preferably 1 to 6 g / m ² .

On the lithographic printing plate support thus obtained,
As a photosensitive layer of a PS plate (abbreviation of Pre-Sensitized Plate), a photosensitive layer that has been conventionally known can be provided to obtain a photosensitive lithographic printing plate. , Has excellent performance.

As the composition of the above-mentioned photosensitive layer, any composition can be used as long as its solubility or swelling property in a developing solution changes before and after exposure. The representative ones will be described below.

As a positive-working photosensitive diazo compound, Japanese Patent Publication No.
-Benzoquinone described in JP-A-28403-
Most preferred are the esters of 1,2-diazidosulfonic acid chloride with polyhydroxyphenyl or the esters of naphthoquinone-1,2-diazidosulfonic acid chloride with pyrogallol-acetone resin. Other relatively suitable o-quinonediazide compounds include benzoquinone-1,2-diazidesulfonic acid chloride or naphthoquinone-1,2 described in U.S. Patent Nos. 3,046,120 and 3,188,210. There are esters of diazide sulfonic acid chloride with phenol formaldehyde resins.

Further, a polymer compound having an orthocarboxylic acid ester repeating unit which is decomposed by an acid as described in JP-A-56-17345, JP-A-60-102.
A compound containing a silyl ester group which is decomposed by an acid as described in JP-A-47-47, or JP-A-60-37.
No. 3,849,137, as well as a composition in which a compound containing a silyl ester group which is decomposed by an acid and a compound which generates an acid upon irradiation with light are combined, as described in US Pat. No. 3,849,137. Compounds containing the described O-nitrocarbinol ester groups are useful.

The compound or composition as described above constitutes a photosensitive layer by itself, but a resin soluble in alkaline water is used as a binder together with a resin of this type. As the resin soluble in alkaline water, 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. Is.

Other useful alkaline water-soluble resins include polyhydroxystyrene, copolymers of polyhalogenated hydroxystyrenated (meth) acrylic acid and other vinyl compounds. The amount of the O-quinonediazide compound in the composition composed of the O-quinonediazide compound and the resin soluble in alkaline water is in the range of 10 to 50% by weight, and is usually about 20 to 40% by weight. To be done. Further, in the composition comprising the O-quinonediazide compound, a cyclic acid anhydride, a dye as an image colorant, or another desired extender (piller) may be appropriately added in order to enhance sensitivity.

A photosensitive composition comprising a diazo resin and a binder.

As a negative-working photosensitive diazo compound, US Pat.
Diphenylamine-p-diazonium salts and forms which are reaction products of the diazonium salts disclosed in each of the specifications of 3,631 and 2,667,415 and an organic condensing agent containing a reactive carbonyl group such as aldol and acetal. Condensation product with aldehyde (so-called photosensitive diazo resin)
Is preferably used. Other useful fused diazo compounds are described in U.S. Patent No. 3,679,419, British Patent No. 1,312,925, U.S. Pat.
It is disclosed in each specification of No. 1,312,926. These types of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts and can therefore be coated from aqueous solutions. Also, these water-soluble diazo compounds are reacted with an aromatic or aliphatic compound having one or more phenolic hydroxyl groups, sulfonic acid groups or both by the method disclosed in British Patent No. 1,280,885, A substantially water-insoluble photosensitive diazo resin which is a reaction product thereof can also be used.

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

In addition, diazo resins described in British Patent No. 1,312,925 are also preferable.

Such a diazo resin is used together with a binder. A preferred binder is an organic polymer having an acid value of 10 to 200, and specific examples thereof include acrylic acid,
A copolymer containing methacrylic acid, crotonic acid or maleic acid as an essential polymerization component, for example, US Pat. No. 4,123,27.
2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, acrylonitrile or methacrylonitrile, acrylic acid or methacrylic acid and optionally terpolymers with other copolymerizable monomers as described in No. 6 or Quaternary copolymer, JP-A-53
-120903, the terminal is a hydroxy group, and acrylic acid or methacrylic acid esterified with a group containing a dicarboxylic acid ester residue, acrylic acid or methacrylic acid, and, if necessary, other Copolymer with a copolymerizable monomer, JP-A-54-9
No. 8614, a monomer having an aromatic hydroxyl group at the terminal (such as N- (4-hydroxyphenyl) methacrylamide), acrylic acid or methacrylic acid, and optionally other Copolymer with at least one copolymerizable monomer, JP-A-56-41
Included are copolymers of alkyl acrylates or methacrylates, acrylonitrile or methacrylonitrile, as described in No. 44, and unsaturated carboxylic acids. Further, acidic polyvinyl alcohol derivatives and acidic cellulose derivatives are also useful.

In the main chain or side chain of the polymer Composition comprising a polymer compound containing a group as a photosensitive group in the polymer main chain or side chain Containing a photosensitive polymer such as polyesters, polyamides, and polycarbonates containing (for example, US Pat. Nos. 3,030,208, 3,707,373 and 3,45).
Compounds as described in each of the 3,237 specifications);
Photosensitive polyesters derived from (2-properidene) malonic acid compounds such as cinnamylidene malonic acid and bifunctional glycols as main components (for example, US Pat. Nos. 2,956,878 and 3,173,787 Sensitized polymers such as those described in U.S. Pat. No. 4,962,819; cinnamic acid esters of hydroxyl-containing polymers such as polyvinyl alcohol, starch, cellulose and the like (eg US Pat.
690,966, No. 2,752,372, No. 2,732,301 and the like, such as photosensitive polymers) are included. In these compositions, other sensitizers, stabilizers,
A plasticizer, a pigment, a dye or the like can be included.

A so-called photopolymerizable composition that causes a polymerization reaction upon irradiation with actinic rays. For example, U.S. Patent Nos. 2,760,863 and
There is a composition comprising an addition-polymerizable unsaturated compound having two or more terminal ethylene groups described in 3,060,023 and a photopolymerization initiator.

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

The coating liquid for forming the photosensitive layer contains the above-mentioned components,
For example, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, 2-
Methoxyethyl acetate, 2-ethoxyethyl acetate, dimethylformamide, methanol, ethanol, n-propanol, i-propanol, methylene chloride, ethylene dioxide, trichloroethane, monochlorobenzene, toluene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl acetate, It is prepared by dissolving it in an organic solvent such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, or an ester such as methylaluminum acetate, or a mixed solvent thereof.
The amount ratio of the solid components in the coating liquid is about 0.1 to about 25% by weight,
More preferably, it is about 1 to 15% by weight.

The prepared coating solution is applied onto the aluminum plate treated as described above by various applying means such as doctor coating, roller coating, gravure coating, bead coating and dip coating. The conventional technique may be applied to dry the coating liquid layer, and the temperature may be from room temperature to high temperature, for example, 2
Dry in an atmosphere with a temperature in the range of 0 ° C to 150 ° C. Photosensitive layer after drying is about ^{0.1~7g / m 2, 0.5~4g / m} 2 is more preferred amount.

The photosensitive lithographic printing plate thus obtained is imagewise exposed by a light source containing an actinic ray such as a carbon arc lamp, a xenon lamp, a mercury lamp, a tungsten lamp, a metal halide lamp, and the like, and a suitable developing solution such as the above-mentioned photosensitive composition is used. The photosensitive layer of the product becomes a planographic printing plate when developed with an aqueous solution of an alkali such as potassium silicate.

〔The invention's effect〕

The lithographic printing plate using the aluminum support obtained by the present invention gives a high printing durability as compared with the conventional substrate subjected to the hydrophilization treatment by silicate treatment, and at the same time, has a remarkable effect that the non-image area is less likely to be stained. Is obtained. Conventionally, a lithographic printing plate having a high printing durability has a property that the non-image area is easily soiled, and conversely, a lithographic printing plate which is less likely to be soiled in the non-image area has a property that the printing durability is low. Was said to be extremely difficult.

However, the lithographic printing plate using the aluminum support according to the present invention has high printing durability and, at the same time, has an unprecedented excellent property that the non-image area is hardly soiled.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples. In addition, "%" in the examples means "% by weight" unless otherwise specified.

Example 1 The surface of a JIS 1050 aluminum sheet was grained with a rotating nylon brush using a pumice-water suspension as an abrasive.
At this time, the surface roughness (centerline average roughness) was 0.5 μ. After washing with water, immersing a 10% aqueous solution of caustic soda in a solution heated to 70 ° C., the dissolution amount on the aluminum surface is 6 g /
Etched to m ² .

After washing with water, immersing in a 30% nitric acid aqueous solution for 1 minute for acid washing, and then in a 0.7% nitric acid aqueous solution, the voltage at the anode was 13 V,
Alternating rectangular wave with a voltage of 6 volts at the cathode (Japanese Patent Laid-Open No. 52-7
Electrolytic surface roughening is performed for 20 seconds using the power supply waveform described in the Examples of JP-A-7702), the surface is washed by immersing it in a solution of 30% nitric acid at 50 ° C., and then washed with water to form a substrate [I]. Obtained.

Substrate [A] was prepared by anodizing substrate [I] in a 20% sulfuric acid aqueous solution using direct current so that the weight of the anodized film was 3.0 g / m ² , washing with water and drying.

Substrate [A] is made of No. 3 sodium silicate solution 2.5%, 70 ° C, 30
Substrate with a silicate layer film formed by dipping in seconds [B]
Prepared.

The substrate [B] was immersed in boiling water for 30 seconds to prepare a substrate [C].

Further, the substrate [I] was subjected to a sodium silicate immersion treatment under the same conditions as the substrate [B], and then anodized under the same conditions as the substrate [A] to obtain a substrate [D]. Samples [A] to [D] were prepared.

On the other hand, the substrate [I] is treated with boiling water or an aqueous solution of triethanolamine, soaked with sodium silicate under the same conditions as those for the substrate [B], and then anodized under the same conditions as for the substrate [A]. A sample of this example was prepared. Substrate [E] was treated with boiling water for 30 seconds, substrate [F] was treated with boiling water for 15 minutes, and triethanolamine aqueous solution 0.1
The substrate [G] was treated at 60% capacity for 2 minutes,
Each of [A] to [G] was provided with the following photosensitive layer so that the coating weight after drying was 2.5 g / m ² .

Composition Naphtoquinone-1,2-diazide-5-sulfonyl chloride, an ester compound of pyrogallol and an acetone resin (described in US Pat. No. 3,635,709 Example 1) Cresol novolac resin 2.00 g Oil blue # 603 (manufactured by Orient Chemical Co., Ltd. ) 0.04 g ethylene dichloride 16 g 2-methoxyethyl acetate 12 g The photosensitive lithographic printing plate thus prepared was exposed for 50 seconds through a transparent positive film from a distance of 1 m through a 3 KW metal halide lamp in a vacuum baking frame. After that, development was performed with a 5.26% aqueous solution of sodium silicate (pH = 12.7) having a SiO ₂ / Na ₂ O molar ratio of 1.74.

After developing in this way, the product was thoroughly washed with water, gummed, and then printed by a conventional procedure. Table 1 shows the results of examining the contamination and printing durability of the non-image area at this time. Substrate [E],
[F] and [G] are examples of the present invention.
[B], [C], and [D] are comparative examples.

As shown in the results of Table 1, the sample prepared by the manufacturing method of the present invention was superior in stain resistance to the non-image area and was excellent in printing durability as compared with Comparative Example. Further, the method of the present invention showed the effect that the plate surface was not easily soiled even if it was left overnight without any treatment.

* Difficulty of stains on non-image area: The following criteria were used to evaluate the stains on the printed matter or ink transferred to the non-image area on the blanket when printing 1,000 or more sheets.

○: No stains on printed matter or blanket.

○ △ …… The blanket is dirty, but the printed material is clean.

△: The blanket is dirty and some stains are found on the printed matter.

× …… The blanket is dirty and the printed matter is also very dirty.

Claims (1)

[Claims] 1. A method of forming a hydrate of aluminum on at least one surface of a grained aluminum plate, treating the surface with a silicate, and then performing anodizing treatment. A method for producing a support for a lithographic printing plate.