JPH0624166A - Supporting body for lithographic printing plate and its manufacture and manufacture for photosensitive lithographic printing plate - Google Patents

Abstract

PURPOSE:To improve adhesive properties, resistances to printing and the water retention by turning the surface of an aluminum plate rough and forming pits without edges of a predetermined average opening diameter with a predetermined density all over the rough surface. CONSTITUTION:The surface of an aluminum plate 1 is mechanically processed to be a rough surface, and fine sharp undulations 3 are formed all over the ridges 2 and ravines. Thereafter, chemical etching is performed in the region of 5-30g/m<2>, thereby removing the undulations 3. Then, pits 4 are formed by turning the surface rough through the alternating electrolysis in an acid aqueous solution with the current density at the anode of 10-60A/dm<2> and the quantity of electricity at the anode of 200-600 Coulomb/dm<2>. The pits 4 having the average opening diameter of 0.2-5mum are formed 3X10<6>-9X10<8>/cm<2> all over the surface. The edges of the pits 4 are removed to make the pits smooth by the chemical etching in the region of 0.1-10g/m<2> by means of a base. An anodic oxidation film is formed through the anodic oxidation to add abrasion resistances and corrosion resistances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate support, a process for producing the same, and a process for producing a photosensitive lithographic printing plate using the same. More specifically, it has a surface excellent in water retention.
Moreover, the present invention relates to an aluminum support for a lithographic printing plate which has good adhesion between an aluminum support and a photosensitive layer and is excellent in printing durability, a method for producing the same, and a method for producing a photosensitive lithographic printing plate using the same. .

[0002]

2. Description of the Related Art Aluminum plates have been widely used as a support for lithographic printing plates, but they have been used in order to improve the adhesion between the support and the photosensitive layer and to impart water retention to the non-image area. A so-called graining treatment for roughening the surface is performed. Specific means of this graining treatment method are mechanical sand such as sand blast, ball grain, wire grain, brush grain by nylon brush and abrasive / water slurry, honing grain by spraying abrasive / water slurry at high pressure on the surface. There are a graining method and a chemical graining method in which the surface is roughened with an etching agent composed of a base, an acid or a mixture thereof. Further, the electrochemical graining methods described in JP-A-54-146234 and JP-A-48-28123, for example, JP-A-53-123205, JP-B-57-16918, JP-A-57-16918. 62-
A method combining a mechanical graining method and an electrochemical graining method described in Japanese Patent No.
There is also known a method in which a mechanical graining method described in Japanese Patent Publication No. 55261 is combined with a chemical graining method using a saturated aqueous solution of an aluminum salt of a mineral acid.

Among the various surface-roughening treatment methods described above, the electrolytic surface-roughening treatment can be mentioned as a method for easily controlling the shape of the rough surface and obtaining a fine rough surface. Since the roughened aluminum surface is soft as it is and is easily worn, the surface of the aluminum is anodized to form an oxide film, and the photosensitive layer is provided thereon. The surface of the aluminum plate thus treated is hard and has excellent abrasion resistance, and exhibits good hydrophilicity, water retention and adhesion to the photosensitive layer.

[0004]

With respect to the electrolytic surface-roughening treatment described above, the electrolytically surface-roughening treated surface is immediately anodized due to the adhesion of smut, so that the anodized film becomes black and the appearance Not only significantly deteriorating the physical value, but also degrading or varying the sensitivity of the photosensitive layer coated thereon, and degrading the plate inspection property even after development. In addition, scumming is likely to occur.

In particular, Japanese Patent Publication No. 57-16918 discloses a process of mechanically polishing, chemically etching with acid or base, and electrochemically roughening the surface. In this case, , Although it is desmutted with acid after electrochemically roughening, it causes scumming etc. (This matter is described in the opinion statement for the notification of reasons for refusal in Japanese Patent Publication No. 62-25117). ). In addition, Japanese public Sho 62-25117
In the publication, a support having a rough surface structure having plateaus on an aluminum surface, a plateau structure on which the plateaus are left, and pits uniformly dispersed, is described. The method is mechanical polishing, chemical etching, and 20 A / in a hydrochloric acid / nitric acid-based aqueous solution.
It has been disclosed that electrolytic surface roughening is performed at an anodic quantity of electricity not exceeding 200 coulomb / dm ² under an anodic current density of dm ² or more. However, in this method, since a plateau is formed, the specific surface area becomes small, the water retention is poor, and a large amount of dampening water must be discharged, so that high-quality printed matter cannot be obtained.

On the other hand, Japanese Patent Application Laid-Open No. 48-28123 discloses a method of etching after electrolytic graining treatment in a hydrochloric acid electrolytic solution. In the case of alkali etching, not only smut removal but also the etching rate is fast, so if this treatment is applied to the surface of a single rough surface structure that has been electrolytically roughened in hydrochloric acid, the grain structure will be too smooth. I will end up. As a result, the adhesion to the photosensitive layer is reduced and the printing durability is reduced. From the above problems, excellent water retention and excellent printing durability,
Also, a support capable of providing a photosensitive lithographic printing plate which has the property that the non-image area is not easily soiled is desired.

[0007]

In order to solve the above problems, the present invention mechanically roughens the surface of an aluminum plate to form undulations, and to form sharp irregularities on the entire surface of the undulations.
Next, it is chemically etched in a range of 0.5 to 30 g / m ² to preferably eliminate only sharp irregularities, or to form a smooth shape without corners, and further 10 to 60 A / dm ^{2 at} an anode current density, 20
The average opening diameter of the pits preferably formed by performing AC electrolytic surface roughening in an acidic aqueous solution at an anode electricity of 0 to 600 coulombs / dm ² is 0.2 to 5 μm and 3 × 10 ^{6 to} 9 × 10 ⁸ pieces / cm ²
Pits are formed over the entire surface, and then 0.
In the range of 1 to 10 g / m ² by performing a chemical etching and smooth shape without corners the pit, and the lithographic printing plate support and finally anodized by forming an anodic oxide coating, this The present invention provides a photosensitive lithographic printing plate using a lithographic printing plate support.

The aluminum or its alloy plate (hereinafter simply referred to as "aluminum plate") which is the support for the lithographic printing plate used in the present invention includes JIS A-1050 material and JIS A-1100.
Materials, JIS A-3003 materials, JIS A-3103 materials, JIS A-5005 materials and the like. These aluminum plates may be subjected to a pretreatment prior to being mechanically roughened to remove rolling oil on the surface as necessary or to expose a clean aluminum surface. Good. To this end, solvents such as trichlorethylene, surfactants, sodium silicates,
An alkaline aqueous solution such as sodium hydroxide or potassium hydroxide is widely used.

Following the above-mentioned pretreatment, mechanical polishing is performed. As a method for mechanically roughening the surface of the aluminum plate, various conventionally known methods can be used. For example, methods such as sand blasting, ball grain, wire grain and brush grain are included, and among these, brush grain is particularly preferable. For details of the brush grain method, see Japanese Patent Publication No. 51-46003 (or US Pat. No. 3,891,516) and Japanese Patent Publication No. 50-40.
No. 047. Mechanical surface roughening is preferably performed so that the center line average roughness Ra of the lithographic printing plate support obtained by the method of the present invention is 0.4 to 1.0 μm. Here, the center line average roughness Ra of the grain is JIS B 0.
As shown in 601 (1970), a portion of the measurement length 1 is extracted from the roughness curve in the direction of the center line, the center line of the extracted portion is taken as the X axis, and the vertical direction is taken as the Y axis. When the height curve is represented by y = f (x), the value of Ra given by the following equation (1) is represented in units of microns.

[0010]

[Equation 1]

The degree of mechanical surface roughening for controlling the range of Ra as described above depends on the conditions of the electrochemical surface roughening to be performed later, and additional treatments if necessary. If is determined, it can be easily determined by those skilled in the art. Due to this mechanical roughening, the surface of the aluminum plate has undulations with a relatively large period and minute sharp irregularities formed over the entire surface of the undulations.

The surface of the aluminum plate mechanically roughened as described above is then chemically etched. This chemical etching treatment removes the abrasives, aluminum scraps, etc. that dig into the surface of the mechanically roughened aluminum plate, and also eliminates the above-mentioned minute sharp irregularities or creates a smooth shape without corners. It has a function and can achieve the electrochemical roughening performed thereafter more uniformly and effectively. Details of such a chemical etching method are described in U.S. Pat. No. 3,834,998, which is a method of immersing aluminum in an aqueous solution of an acid or a base capable of dissolving aluminum. Examples of the above acid include sulfuric acid, persulfuric acid, hydrochloric acid, etc., and examples of the above base include:
It includes sodium hydroxide, potassium hydroxide, sodium triphosphate, sodium diphosphate, potassium triphosphate, potassium diphosphate, sodium aluminate, sodium carbonate and the like. Among these, it is particularly preferable to use the latter aqueous solution of a base because the etching rate is faster.

The amount of etching is appropriately selected from the range of 0.5 to 30 g / m ² , preferably ^{2 to 20} g / m ² . If the amount of this etching is less than 0.5 g / m ² , uniform pits cannot be generated in the electrolytic etching in the next step, and if it exceeds 30 g / m ² , mechanically roughened comparison is performed. The large ups and downs of the periodic cycle disappear. The concentration of the above-mentioned acid or base used as an etching agent is preferably 0.05 to 40% by weight, the liquid temperature is 40 to 100 ° C., and the treatment time is preferably 5 to 300 seconds. When the above chemical etching is carried out using an aqueous solution of a base, smut is generally formed on the surface of aluminum. In this case, therefore, phosphoric acid, nitric acid, sulfuric acid, chromic acid or two or more of these are used. It is preferable to perform so-called desmut treatment, which is a treatment with a mixed acid containing an acid.

The aluminum plate treated as described above is then placed in an acidic electrolytic solution such as hydrochloric acid or nitric acid for 10 to 60 times.
AC electrolytic graining is performed with an anode current density of A / dm ^{2 and} an anode electricity of 200 to 600 coulombs / dm ² . The current used at this time is preferably an alternating waveform current having a waveform obtained by alternately exchanging positive and negative polarities. In the present invention, the electrolytic bath used in the method of electrochemical surface roughening is
Hydrochloric acid or nitric acid, the concentration of which is about 0.1 in each case.
Suitably, it is selected from the range of weight percent to about 10 weight percent. Further, these electrolytic baths may further contain a corrosion inhibitor (or stabilizer). For example, in the case of a nitric acid electrolytic bath, nitrates such as zinc nitrate, ammonium nitrate and sodium nitrate, monoamines, diamines, aldehydes, phosphoric acid, chromic acid, sulfosalicylic acid and the like can be mentioned. The amount of these corrosion inhibitors added to the electrolytic solution is preferably selected from the range of about 0.05% by weight to about 3% by weight.

Further, as the alternating waveform current used in the present invention, not only sinusoidal single-phase and three-phase alternating currents but also trapezoidal and rectangular wave alternating currents can be used. It is described in detail in US Pat. No. 4,087,341. Ratio of electricity quantity Qc at anode and electricity quantity Qa at cathode Qc / Q
a, By adjusting the current density at the anode and the amount of electricity at the anode, the average opening diameter of pits of 0.2 to 5 μm, the number of pits 3 ×
It is possible to produce a grain having 10 ^{6 to} 9 × 10 ⁸ pieces / cm ² formed on the entire surface. The amount of electricity at the anode is 200 to 600 coulombs / dm ² above.
However, 200 to 400 coulomb / cm ² is particularly preferable. If the amount of electricity at the time of anode is less than 200 coulomb / dm ² , pits cannot be formed on the entire surface, resulting in deterioration of water retention and printing durability. ^{On the other hand} , if it exceeds 600 coulombs / dm ² , pits having a large diameter are nonuniformly formed, and the number of pits is less than 3 × 10 ^6, resulting in poor water retention. On the other hand, the current density at the anode is 10 to 60 A / dm ²
However, 20 to 50 A / dm ² is particularly preferable. If the current density at the time of the anode is less than 10 A / dm ² , the processing time becomes long, which may cause a manufacturing problem, or it may not be possible to manufacture pits on the entire surface. On the other hand, when it exceeds 60 A / dm ² , the pit diameter becomes non-uniform and the water retention property also deteriorates, and the effect of the present invention cannot be achieved. Furthermore, the ratio of Qc / Qa is 0.75
It is preferably ˜1.5.

After the completion of the electrolytic surface roughening, the aluminum plate is chemically etched again with a base. This etching is the same as the method of immersing in the aqueous solution of the above base, and the above base such as sodium hydroxide is used. This etching amount is in the range of 0.1 to 10 g / m ² . Etching amount is 0.1g / m
If it is less than ^{2, the} protruding portions between pits obtained by electropolishing cannot be dissolved to form a smooth structure without corners, and scumming tends to occur. On the other hand, 10 g / m ²
If it exceeds, the pits obtained by electropolishing will disappear, and problems such as water retention will occur. The concentration of the above base used as an etching agent is 0.05 to 20% by weight, and the temperature is
It is preferable that the treatment time is 40 to 100 ° C. and the treatment time is 1 to 100 seconds. After the chemical etching with the base, it is preferable to perform desmut treatment with phosphoric acid, nitric acid, sulfuric acid, chromic acid or the like.

The aluminum plate treated as described above is then anodized. This anodizing treatment can be performed according to a known method. For example, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, amidosulfonic acid or a mixture of two or more thereof, or an aqueous solution or a non-aqueous solution containing Al3 + ions in them is used as an electrolytic solution, and anodizing is mainly performed using direct current. However, alternating current or a combination of these currents can also be used. At this time, the electrolyte concentration is 1 to 80% by weight, the temperature is in the range of 5 to 70 ° C, and the current density is
The range of 0.5 to 60 A / dm ^{2 and} the weight of oxide film are preferably 0.3 to 6 g / m ² .

The aluminum plate anodized as described above is further prepared in US Pat. No. 2,714,066 and US Pat. No. 3,181,4.
As described in each specification of No. 61, it can be hydrophilized by a method of immersing in an aqueous solution of an alkali metal silicate, for example, sodium silicate. Further, an undercoat layer made of a polymer compound containing a monomer unit having a sulfonic acid group described in JP-A-59-101651 and NH4 described in JP-A-60-149491.
An undercoat layer made of a compound having a group, a COOH group, or a SO3H group can also be used.

On the lithographic printing plate support thus obtained, a photosensitive layer conventionally known can be provided to obtain a photosensitive lithographic printing plate, which is subjected to a plate making treatment. The lithographic printing plate thus obtained has excellent performance. The photosensitive substance used in the photosensitive layer is not particularly limited, and various substances generally used in photosensitive lithographic printing plates, for example, the following various substances can be used. 1) Photocrosslinking-type photosensitive resin composition The photosensitive component in the photocrosslinking-type photosensitive resin composition is composed of a photosensitive resin having an unsaturated double bond in the molecule, for example, US Pat. No. 3,030,208. , No. 3,435,237 and No. 3,622,320, etc., the following (chemical formula 1) as a photosensitive group in the polymer main chain or side chain is described.
And a photosensitive resin such as polyvinyl cinnamate.

[0020]

[Chemical 1]

2) Photopolymerizable Photosensitive Resin Composition A photopolymerizable composition containing an addition-polymerizable unsaturated compound, which comprises a monomer having a double bond and a polymer binder. Representative examples of these are described in, for example, U.S. Pat.Nos. 2,760,863 and 2,791,504, and specific examples thereof include a composition containing methyl methacrylate and methyl polymethyl methacrylate. A composition comprising, methyl methacrylate polymethyl methacrylate and a composition comprising polyethylene glycol dimethacrylate monomers, methyl methacrylate,
Photopolymerizable compositions such as compositions containing alkyd resins and polyethylene glycol dimethacrylate monomers. The photopolymerization type photosensitive resin composition includes a photopolymerization initiator usually known in this technical field (for example, benzoin derivative such as benzoin methyl ether, benzophenone derivative such as benzophenone, thioxanthone derivative,
Anthraquinone derivative, acridone derivative, etc.) are added.

3) Photosensitive Composition Containing Diazo Compound The diazo compound in the photosensitive composition is, for example, preferably a diazo resin typified by a condensation product of an aromatic diazonium salt and formaldehyde or acetaldehyde. Particularly preferably, a salt of a condensate of p-diazodiphenylamine and formaldehyde or acetaldehyde,
For example, hexafluorophosphate, tetrafluoroborate, perchlorate or diazo resin inorganic salt which is a reaction product of periodate with the condensate, and US Pat.
Examples thereof include a diazo resin organic salt which is a reaction product of the condensate and a sulfonate as described in No. 9 specification. Furthermore, diazo resins are preferably used with binders. As the binder, various polymer compounds can be used, preferably JP-A-54-9.
A monomer having an aromatic hydroxyl group as described in 8613, for example, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, o-, m-, or Copolymers of p-hydroxystyrene, o-, m-, or p-hydroxyphenylmethacrylate with other monomers, US Pat.
Polymers containing hydroxyethyl acrylate units or hydroxyethyl methacrylate units as the main repeating unit, shellac, natural resins such as rosin, polyvinyl alcohol, etc.
From polyamide resins as described in U.S. Pat. No. 3,751,257, linear polyurethane resins as described in U.S. Pat. No. 3,660,097, phthalated resins of polyvinyl alcohol, bisphenol A and epichlorohydrin Condensed epoxy resins, cellulose derivatives such as cellulose acetate, cellulose acetate and cellulose phthalate are included.

4) Photosensitive composition containing o-quinonediazide compound In a photosensitive composition containing an o-quinonediazide compound, it is preferable to use this o-quinonediazide compound in combination with an alkali-soluble resin. Examples of the o-quinonediazide compound include ester compounds of o-naphthoquinonediazide sulfonic acid and a polycondensation resin of phenols and aldehydes or ketones.

Examples of the phenols include monohydric phenols such as phenol, o-cresol, m-cresol, p-cresol, 3,5-xylenol, carvacrol and thymol, and dihydric compounds such as catechol, resorcinol and hydroquinone. Examples include trihydric phenols such as phenol, pyrogallol, and phloroglucin. Examples of the aldehyde include formaldehyde, benzaldehyde, acetaldehyde, crotonaldehyde, furfural and the like. Preferred of these are formaldehyde and benzaldehyde. Examples of the ketone include acetone and methyl ethyl ketone. Specific examples of the polycondensation resin include phenol / formaldehyde resin, m-cresol / formaldehyde resin, m- and p-mixed cresol / formaldehyde resin, resorcin / benzaldehyde resin, and pyrogallol / acetone resin. The condensation rate of the o-naphthoquinonediazide sulfonic acid with respect to the OH group of phenols (reaction rate with respect to one OH group) is preferably 15 to 80%, more preferably 20 to 45%.

Further, as the o-quinonediazide compound used in the present invention, the following compounds described in JP-A-58-43451 can also be used. That is, for example, 1,2-
Known 1,2-quinonediazide compounds such as benzoquinonediazidesulfonic acid ester, 1,2-naphthoquinonediazidesulfonic acid ester, 1,2-benzoquinonediazidesulfonic acid amide, and 1,2-naphthoquinonediazidesulfonic acid amide, and more specifically Is "Light Sensitive Systems" by J. Kosar (L
ight-Sensitive Systems) pp. 339-352 (1965
Year), John Wiley and Sons
& Sons) (New York) and W.S.D.
"Photoresist" by WS De Forest (P
Hotoresist, Vol. 50, (1975), 1,2-benzoquinonediazide-4-sulfonic acid phenyl ester, 4,4'-di- (McGraw-Hill, New York). 1,2-benzoquinonediazide-4-sulfonyloxy) -biphenyl, 1,2-
Benzoquinonediazide-4- (N-ethyl-N-β-naphthyl) -sulfonamide, 1,2-naphthoquinonediazide-5-sulfonic acid cyclohexyl ester, 1-
(1,2-naphthoquinonediazide-5-sulfonyl)-
3,5-Dimethylpyrazole, 1,2-naphthoquinonediazide-5-sulfonic acid-4'-hydroxydiphenyl-4'-azo-β-naphthol-ester, N, N-di- (1,2-naphthoquinonediazide- 5-sulfonyl)
-Aniline, 2 '-(1,2-naphthoquinonediazide-
5-sulfonyloxy) -1-hydroxy-anthraquinone, 1,2-naphthoquinonediazide-5-sulfone-
2,4-dihydroxybenzophenone ester, 1,2
-Naphthoquinonediazide-5-sulfonic acid-2,3,4
-Trihydroxybenzophenone ester, a mixture of 2 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mol of 4,4'-diaminobenzophenone,
Condensation product of 2 mol of 1,2-naphthoquinonediazide-5-sulfonic acid chloride and 1 mol of 4,4'-dihydroxydiphenylsulfone, 1,2-naphthoquinonediazide-5
A condensate of 1 mol of sulfonic acid chloride and 1 mol of purpurogallin, 1,2-naphthoquinonediazide-5- (N-
1,2-such as dihydroabietyl) -sulfonamide
A quinonediazide compound can be illustrated. Also,
Japanese Examined Japanese Patent Publication No. 37-1953, 37-3627, 37-13109, 40-2
No. 6126, No. 40-3801, No. 45-5604, No. 45-27345, No.
51-13013, JP-A-48-96575, 48-63802, 48-6
The 1,2-quinonediazide compounds described in Japanese Patent No. 3803 can also be mentioned.

Of the above o-quinonediazide compounds,
Condensation resin of 1,2-benzoquinone diazide sulfonyl chloride or 1,2-naphthoquinone diazide sulfonyl chloride and pyrogallol-acetone, and o-quinone diazide ester compound obtained by reacting the above quinone compound with 2,3,4-trihydroxybenzophenone Is particularly preferable. As the o-quinonediazide compound, the above compounds may be used alone or in combination of two or more kinds. Further, the proportion of the o-quinonediazide compound in the photosensitive composition is preferably 5 to 60% by weight, particularly preferably 10 to 50% by weight.

Examples of the alkali-soluble resin used in the photosensitive composition of the present invention include novolac resins, vinyl polymers having a phenolic hydroxyl group, and JP-A-55-57841.
Condensation resins of polyhydric phenols and aldehydes or ketones, which are described in the publication, are mentioned. Examples of the novolac resin include phenol / formaldehyde resin, cresol / formaldehyde resin, JP-A-55-578.
Phenol-cresol-formaldehyde copolymer resin as described in Japanese Patent No. 41, JP-A-55-127553
Examples thereof include a copolymer resin of p-substituted phenol and phenol or cresol and formaldehyde as described in JP-A No. 1994-242242. The molecular weight (polystyrene standard) of this novolak resin is preferably a number average molecular weight Mn.
Is 3.00 × 10 ^{2 to} 7.50 × 10 ³ , and the weight average molecular weight Mw is 1.00.
× 10 ^{3 to} 3.00 × 10 ⁴ , more preferably Mn is 5.00 × 10 ^2.
˜4.00 × 10 ³ , and Mw is 3.00 × 10 ^{3 to} 2.00 × 10 ⁴ .
The novolac resins may be used alone or in combination of two or more. The proportion of the novolac resin in the photosensitive composition according to the present invention is generally 5 to 95% by weight.

The vinyl polymer having a phenolic hydroxyl group used in the present invention is a polymer having a unit having this phenolic hydroxyl group in its molecular structure, and is represented by the following general formulas (Formula 2) to (Formula 2) Polymers containing at least one structural unit represented by 6) are preferred.

[0029]

[Chemical 2]

[Chemical 3]

[Chemical 4]

[Chemical 5]

[Chemical 6]

[In the formula, R ₁ and R ₂ each represent a hydrogen atom, an alkyl group or a carboxyl group, and preferably a hydrogen atom. R ₃ represents a hydrogen atom, a halogen atom or an alkyl group, preferably a hydrogen atom or an alkyl group such as a methyl group or an ethyl group. R ₄ represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and preferably a hydrogen atom. A represents an optionally substituted alkylene group which connects a nitrogen atom or an oxygen atom and an aromatic carbon atom, m represents an integer of 0 to 10, and B represents a substituent. It represents a good phenylene group or a naphthylene group which may have a substituent. ]

As the polymer used in the photosensitive composition according to the present invention, those having a copolymer type structure are preferable, and in combination with the structural units represented by the general formulas (Formula 2) to (Formula 6), respectively. Can be used. As the monomer unit, for example, ethylene, propylene, isobutylene, butadiene, isoprene and other ethylenically unsaturated olefins such as styrene, α-methylstyrene,
Styrenes such as p-methylstyrene and p-chlorostyrene, acrylic acids such as acrylic acid and methacrylic acid, and unsaturated aliphatic dicarboxylic acids such as itaconic acid, maleic acid and maleic anhydride, such as methyl acrylate and acrylic acid. Ethyl acid, acrylic acid-n-butyl, isobutyl acrylate, dodecyl acrylate, acrylic acid-
Esters of α-methylene aliphatic monocarboxylic acids such as 2-chloroethyl, phenyl acrylate, α-chloromethyl acrylate, methyl methacrylate, ethyl methacrylate and the like, nitriles such as acrylonitrile and methacrylonitrile, such as acrylamide and the like. Amides such as acrylanilide, p-chloroacrylanilide,
Anilides such as m-nitroacrylanilide and m-methoxyacrylanilide, for example vinyl acetates such as vinyl acetate, vinyl propionate, vinyl benzoic acid and vinyl butyrate, such as methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, β-chloroethyl. Vinyl ethers such as vinyl ether, vinyl chloride, vinylidene chloride, vinylidene cyanide, such as 1-methyl-1-methoxyethylene, 1,1-dimethoxyethylene, 1,2-dimethoxyethylene, 1,1-dimethoxycarbonylethylene, 1- Ethylene derivatives such as methyl-1-nitroethylene, such as N-vinylpyrrole, N
There are N-vinyl monomers such as -vinylcarbazole, N-vinylindole, N-vinylpyrrolidine and N-vinylpyrrolidone. These vinyl-based monomers are present in the polymer compound with a structure in which the unsaturated double bond is cleaved.

Of the above-mentioned monomers, aliphatic monocarboxylic acid esters and nitriles are preferable because they exhibit excellent performance for the purpose of the present invention. Further, these monomers may be bonded to the polymer used in the present invention in either a block or random state. The ratio of the vinyl polymer used in the present invention in the photosensitive composition is generally 0.5 to 70% by weight. As the vinyl polymer, the above polymers may be used alone or in combination of two or more kinds. It can also be used in combination with other polymer compounds.

A printout material capable of forming a visible image upon exposure can be added to the above-mentioned photosensitive composition. This printout material is composed of a compound that produces an acid or a free radical upon exposure to light and an organic dye that changes its color tone by interacting with it. Examples of the compound that produces an acid or a free radical upon exposure to light include O-naphthoquinonediazide-4-sulfonic acid halides described in JP-A-50-36209, trihalomethyl-2-pyrone and trihalomethyl-triazine described in JP-A-53-36223, and JP-A-55 No. 6244, an ester compound or amide compound of o-naphthoquinonediazide-4-sulfonic acid chloride and a phenolic acid having an electron-withdrawing substituent or aniline acid, JP-A-55-7
Examples thereof include halomethylvinyloxadiazole compounds and diazonium salts described in JP-A 7742 and JP-A-59-148784.

As the above-mentioned organic dye, Victoria Pure Bull-BOH (manufactured by Hodogaya Chemical Co., Ltd.),
Patent Pewable- (Sumitomo Sangoku Chemical Co., Ltd.),
Oil Blue # 603 (Orient Chemical Industry Co., Ltd.)
Made), Sudan blue II (made by BASF), crystal violet, malachite green, fuchsin, methyl violet, ethyl violet, methyl orange,
Brilliant green, Congo red, eosin, Rhodamine 6G and the like can be mentioned. In addition to the above materials, a plasticizer, a surfactant, an organic acid, an acid anhydride and the like can be added to the photosensitive composition, if necessary.
Furthermore, in order to improve the photosensitivity of the photosensitive composition used in the present invention, for example, p-tert-butylphenolformaldehyde resin, pn-octylphenolformaldehyde resin, or these resins may be used. It is also possible to add a resin partially esterified with an o-quinonediazide compound.

Each of these components is dissolved in a solvent, and the solution is applied on the surface of a support and dried to provide a photosensitive layer, whereby the photosensitive lithographic printing plate of the present invention can be produced. As the solvent, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, Diethylene glycol monoisopropyl ether, propylene glycol, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol methyl ethyl ether Le, ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate,
Ethyl propionate, methyl butyrate, ethyl butyrate, dimethylformamide, dimethyl sulfoxide, dioxane,
Acetone, methyl ethyl ketone, cyclohexanone, methylcyclohexanone, diacetone alcohol, acetylacetone, γ-butyrolactone and the like can be mentioned. These solvents can be used alone or in combination of two or more.

The method of applying the photosensitive composition used in the present invention to the surface of a support is conventionally known, for example, spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating and Curtain coating or the like is used. The coating amount varies depending on the use, but for example, an amount such that the photosensitive layer is coated at 0.05 to 5.0 g / m ³ is preferable.

In using the photosensitive lithographic printing plate thus obtained, a conventionally used method can be applied. For example, a transparent original image having a line image, a halftone dot image or the like is adhered to the photosensitive layer. A relief image is obtained by exposing and then developing the exposed plate material with a suitable developing solution to remove the photosensitive layer in the non-image areas. As a light source suitable for exposure, a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, a carbon arc lamp or the like is used, and as a developer used in the production, an alkaline aqueous solution is preferable, for example, sodium silicate or potassium silicate. An alkaline aqueous solution such as an aqueous solution of sodium hydroxide, potassium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, sodium carbonate, potassium carbonate or tetramethylammonium hydroxide is preferred. The concentration of the alkaline aqueous solution at this time varies depending on the kind of the photosensitive composition and the base, but is generally in the range of 0.1 to 10% by weight, and the acidic alkaline aqueous solution may contain a surfactant or an alcohol as necessary. It is also possible to add an organic solvent such as.

[0038]

In the present invention, the surface of the aluminum plate is mechanically roughened to form undulations, and sharp irregularities are formed on the entire surface of the undulations. Then, the sharp irregularities are eliminated by chemical etching or Make it a gentle shape without corners,
Further, minute pits are formed over the entire surface of the undulation by electrolytic graining, and then chemical etching is performed with a base to form the pits into a gentle shape without corners.

[0039]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a process drawing showing an example of the production of a lithographic printing plate support according to the present invention and a photosensitive lithographic printing plate using this support. In this figure, (a) shows the state of the substrate surface when the aluminum plate 1 is mechanically roughened, and the undulations 2 are formed and the entire top surface of the undulations 2 has fine sharp irregularities. 3 is formed. (b) shows a state in which the first chemical etching is performed, and the sharp irregularities 3 disappear or have a gentle shape with no corners. (c) shows a state in which pits 4 are formed after electrolytic graining, and pits 4 having sharp corners are formed on the entire surface. The last (d) shows a state in which the second chemical etching with a base is performed, and the pit 4 has no corner and is gentle. The support for a lithographic printing plate according to the present invention can be obtained by further subjecting this to anodizing treatment for imparting abrasion resistance and corrosion resistance.

Further, FIG. 2 (e) shows a photosensitive lithographic printing plate according to the present invention in which a photosensitive layer 5 is formed on an aluminum plate 1. In this photosensitive lithographic printing plate, the surface of the above anodized aluminum plate 1 is preferably immersed in an aqueous solution of sodium silicate or the like for hydrophilic treatment, and a photosensitive substance, a dye, an alkali-soluble resin, a polymer is added thereto. And a photosensitive layer forming material consisting of solvent etc. by a method such as spin coating 0.05
The photosensitive layer 5 is formed by applying about 5.0 g / m ² and drying.

A more detailed embodiment according to the present invention will be described. Examples 1 to 11 and Comparative Examples 1 to 6 Aluminum plate 1 (JIS A-1050 material) having a thickness of 0.3 mm is 10% N
It was immersed in an aOH aqueous solution at 50 ° C. for 20 seconds for degreasing, washed with water, then neutralized with a 25% H ₂ SO ₄ aqueous solution for 30 seconds and washed with water. Then, the surface of the aluminum plate 1 was brush-polished using a nylon brush and 400 mesh permington water suspension, and then thoroughly washed with water. 20% N of 70 ℃
Using an aOH aqueous solution, the amount of Al dissolved is as follows (Table 1).
Etching was performed so that the amount was as shown in (Table 4).

[0042]

[Table 1]

[Table 2]

[Table 3]

[Table 4]

Then, it was washed with water, desmutted with a 25% nitric acid aqueous solution, and then washed with water. The aluminum plate 1 thus treated was subjected to electrolytic surface roughening with an alternating waveform under the conditions shown in (Table 1) to (Table 4). The pits formed at this time were observed with a SEM scanning electron microscope with a magnification of 5000, and the results of examining the average aperture diameter and the number thereof are also shown in (Table 1) to (Table 4). After electrolytic surface roughening, 70 ℃
1% NaOH aqueous solution was used to dissolve Al (Table 1)
Alkaline etching was performed with the etching amount shown in (Table 4), and the surface was immersed in a 10% H ₂ SO ₄ aqueous solution at 50 ° C for 2 minutes for desmutting treatment, and then anodized in a 10% H ₂ SO ₄ aqueous solution. Then, an oxide film of 2.5 g / m ² was provided. Among the supports prepared in this way, the support of the example was a good one in which the pits 4 had a smooth shape with no corners and were distributed almost uniformly over the entire surface of the undulations 2. Corresponding to each example, A-1 to A-11 in Examples 1 to 11 and B-in Comparative Examples 1 to 6 were used for the supports prepared in this Example and Comparative Examples. The numbers 1 to B-6 are given.

A positive PS plate and a negative PS plate were produced using each of the supports A-1 to A-11 and B-1 to B-6. As for this support, first, a positive PS plate was coated with a photosensitive solution having the following composition to prepare a PS plate having a photosensitive layer having a dry weight of 2.0 g / m ² . Composition of Photosensitive Solution Esterification product of naphthoquinone-2-diazide-5-sulfonic acid chloride and acetone pyrogallol resin 2.6 g Cresol novolac resin 7.0 g Naphthoquinone-1,2-diazide-5-sulfonic acid chloride 0.06 g Oil blue 0.1 g Ethylene glycol monomethyl ether 100g The PS plate obtained was attached under reduced pressure under a positive film for 3k.
It was exposed for 60 seconds from a distance of 1 m using a W ultra-high pressure mercury lamp.

Next, a developer having the following composition was added at a liquid temperature of 25 ° C.
It was immersed for 20 seconds and developed. Developer composition JIS No. 3 sodium silicate 25 g KOH 15 g water 1 kg These were washed with water and rubberized with gum arabic to obtain a printing plate. The lithographic printing plate thus obtained was set in a newspaper offset printing machine Risopia (manufactured by Mitsubishi Heavy Industries, Ltd.) for printing. After the entire surface of the plate was wiped with water to remove gum arabic, the plate surface was dried, the ink roller was dropped, and the printing ink was adhered to the entire surface. Then drop the water stick,
The number of sheets (the number of damaged sheets) until the ink in the non-image area is completely removed and stain-free printed matter is obtained, and the water bar is raised in the state of normal printing, and the ink is non-imaged by not giving water. The number of sheets until the print started to get dirty and the printed matter became dirty (the number of stains) was examined. The results are shown in (Table 1) to (Table 4). The lithographic printing plate of the example was an excellent printing plate with a small number of damaged sheets and a large number of stains.

The optimum scale of dampening water and the printing durability were also examined. The results are shown in (Table 5) to (Table 8) below. As for the dampening water of each sample, the smaller the number on the optimum scale is, the more water can be used. Further, the printing durability represents the number of printable copies, and the larger the number, the better.

[0047]

[Table 5]

[Table 6]

[Table 7]

[Table 8]

Next, for the negative PS plate, each of the same supports as in the case of the positive type was used in a 2.5% sodium silicate aqueous solution.
It was immersed for 1 minute at ℃, washed with water and dried. Each support thus obtained was coated with a photosensitive solution having the following composition to give a dry film thickness.
A negative PS plate of 2.0 g / m ² was prepared. Photosensitive solution composition Copolymer of N- (4-hydroxyphenyl) methacrylamide / 2-hydroxymethacrylate / acrylonitrile / methylmethacrylate / methacrylic acid (= 10: 20: 25: 35: 10 molar ratio) 5.0 g 4- Hexafluorophosphate salt of a condensation product of diazodiphenylamine and formaldehyde 0.5 g Victoria Bull-BOH (manufactured by Hodogaya Chemical Co., Ltd.) 0.1 g 2-methoxyethanol 100 g The negative PS plate thus obtained is negative. Adhesion under reduced pressure under the film, using a 3kW ultra-high pressure mercury lamp, distance 1m
Exposed for 4 seconds.

Then, development processing is performed with a developer having the following composition,
Further, it was rubberized to obtain a lithographic printing plate. Developer composition Benzyl alcohol 450g Triethanolamine 150g Monoethanolamine 10g Isopropylnaphthalene sulfonic acid soda 150g Sodium sulfite 30g Water 8420g The lithographic printing plate obtained in this way is the same as the positive PS plate. (Mitsubishi Heavy Industries, Ltd.) was set and printed. The results are shown in (Table 9) to (Table 12) below.

[0050]

[Table 9]

[Table 10]

[Table 11]

[Table 12]

As is clear from the above results, when the support according to the present invention is used, the water retention is good, and the lithographic printing has both excellent printing durability and stain resistance of the non-image area. You can see that you can get a print.

[0052]

As described above, according to the present invention, undulations are formed on the surface of an aluminum support for a lithographic printing plate, and further smooth pits having no corners are formed on the entire surface of the undulations. Therefore, the adhesion with the photosensitive layer is improved, and as a result, the printing durability is improved. In addition, since the specific surface area of the support is increased by forming the minute pits on the entire surface of the support as described above, the lithographic printing plate produced using this support has good water retention and therefore a fountain solution. Less is required. Furthermore, since the minute pits described above have a gentle shape without corners, they do not affect the surface of the photosensitive layer due to unevenness,
There is no worry of soiling.

[Brief description of drawings]

FIG. 1 is a process chart showing an example of production of a lithographic printing plate support according to the present invention and a photosensitive lithographic printing plate using the support.

[Explanation of symbols]

1 ... Aluminum plate, 2 ... Undulation, 3 ... Sharp irregularities, 4 ...
Pit, 5 ... Photosensitive layer.

Front Page Continuation (72) Inventor Toshimi Aoyama 150 Nakamaruko, Nakahara-ku, Kawasaki-shi, Kanagawa Tokyo Ohka Kogyo Co., Ltd.

Claims (6)

[Claims] 1. The surface of an aluminum plate, which is a support for a lithographic printing plate, has undulations due to roughening, and the average opening diameter of pits is 0.2 to 5 μm and 3 × 10 ^{6 to} 9 × 10 on the undulations.
A lithographic printing plate support characterized by having ⁸ corners / cm ² of smooth pits without corners over the entire surface. 2. A step of mechanically roughening the surface of the aluminum plate, a step of chemically etching the surface of the aluminum plate in the range of 0.5 to 30 g / m ² , and an anode of 10 to 60 A / dm ² . Current density, a step of performing AC electrolytic surface roughening in an acidic aqueous solution at an anode time electricity of 200 to 600 coulombs / dm ² , and then a step of chemically etching with a base in the range of 0.1 to 10 g / m ^2. And a step of finally forming an anodized film by anodizing treatment, the method for producing a lithographic printing plate support. 3. A smooth shape having no corners or sharp edges that are formed on the entire surface of the undulations formed when the surface is mechanically roughened by a subsequent chemical etching step. The method for producing a lithographic printing plate support according to claim 2, wherein 4. The average opening diameter of 0.
The method for producing a lithographic printing plate support according to claim 2, wherein pits of 2 to 5 μm and 3 × 10 ^{6 to} 9 × 10 ⁸ pits / cm ² or more are formed over the entire surface. 5. The method for producing a lithographic printing plate support according to claim 4, wherein the pits are formed into a gentle shape without corners by chemical etching with a base after the electrolytic surface roughening. 6. A method for producing a photosensitive lithographic printing plate, which further comprises the step of providing a photosensitive layer on the lithographic printing plate support according to claim 2.