JP3004508B2 - Positive photosensitive lithographic printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive photosensitive lithographic printing plate comprising a photosensitive composition containing o-quinonediazide. Positive photosensitive lithographic plate having a maximum absorption wavelength at 450 nm, coloring with a dibasic acid dye having two sulfonic acid skeletons, and then coating a layer of a positive photosensitive composition containing o-quinonediazide It concerns printing plates.

[0002]

2. Description of the Related Art A positive photosensitive lithographic printing plate (hereinafter referred to as "positive PS plate") comprising a layer of a positive photosensitive resin composition provided on a previously grained and anodized aluminum support. When exposed through a positive transparent original, the solubility of the exposed portion in a developing solution increases, and when this is treated with a developing solution of a positive photosensitive resin composition, the exposed portion of the photosensitive layer is removed and the support is removed. It is known that the hydrophilic surface is exposed, thus forming a positive image. When the lithographic printing plate thus obtained is used, halftone dots are enlarged by printing. To prevent this, during plate making, sufficient exposure is performed to narrow the dots on the plate, or the center line surface roughness as disclosed in JP-B-59-26479. (Ra)
Or an aluminum support having a surface reflectance of 0.6 to 1.2 μm and a surface reflectance of 50% or more. However, in the production of original films in recent years, the use of a scanner has made it possible to reduce the dot area of the film, and it has become unnecessary to reduce the dot area.
Further, in a squirrel film having a low solid density, when the dots are reduced, the minimum halftone dots disappear. Also,
If the amount of exposure is reduced to produce the minimum halftone dot, light is scattered at the edge of the film, and an unnecessary image of that portion is formed on the plate, and after development, it is necessary to erase with an erasing liquid. Occurs. For this reason, a plate with a large dot reduction has conventionally been desired, but in recent years, a plate with higher fidelity of halftone dot reproduction has been desired.

JP-A-57-118238 discloses a method of adding a compound represented by the general formula [1] to a photosensitive layer to increase sensitivity and faithfully reproduce tone. As described above, the method of adding a specific compound to the photosensitive layer has a drawback that the effect of making tone reproducibility faithful is not so large and that the development tolerance is deteriorated.

[0004]

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(In the general formula [I], R ₁ , R ₂ and R ₃ each represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, a substituted aryl group, an acyl group, a halogeno group, a nitro group or a hydroxyl group. R ₃ may be the same or different.)
No. 49 discloses a method of applying a positive photosensitive composition after coloring the surface of an aluminum plate anodized with an ultraviolet absorbing dye. However, when the dyes described in this patent are used, they do not show sufficiently faithful tone reproducibility. In particular, it has been found that the effect is further reduced when a support having a Ra of 0.6 μm or more is used. When the amount of the ultraviolet absorber added is large, the resulting planographic printing plate has poor chemical resistance.

On the other hand, a negative photosensitive lithographic printing plate (hereinafter abbreviated as "negative PS plate") comprising a support having a hydrophilic surface and a layer of a negative photosensitive resin composition provided thereon. When exposed through the negative transparent original, the photosensitive layer is hardened in the exposed portion or the adhesive force with the support changes, and when this is treated with a developer of a negative photosensitive resin composition, the unexposed portion of the photosensitive layer becomes unexposed. It is known that upon removal the hydrophilic surface of the support is exposed, thus forming on the support a lipophilic positive image composed of the cured negative photosensitive resin composition. In this negative PS plate, increasing the exposure time depends on fluctuations in development processing conditions (for example, development time, etc.) since the exposed portion of the photosensitive layer is more cured and the adhesive force with the support is further improved. This is advantageous in that a change in image intensity is reduced, a stable image is secured, and the intensity of the image is increased, so that a lithographic printing plate having high printing durability can be obtained. On the other hand, however, increasing the exposure time is accompanied by serious disadvantages such as the effect of halation and irradiation, which makes the image thicker, lowers the resolution, and makes it impossible to obtain a printed material with good tone reproducibility. Such drawbacks are particularly noticeable when using a support that scatters light well, such as a roughened aluminum support or a paper support, and when a further roughened aluminum plate is anodized. This tendency was known to be even greater.

[0007] As a negative PS plate which has solved such disadvantages, for example, in US Pat. No. 3,891,516, an aluminum plate is grained with a wet abrasive such as a pumice slurry, and then sulfuric acid is immediately added. Negative PS plates using an aluminum support having a surface exhibiting a dark steel gray tone obtained by anodizing in water have been proposed. However, since the surface of the aluminum support of the negative PS plate has a low reflectance from the ultraviolet region to the visible light region, a printed image obtained at the time of image exposure becomes difficult to see, and a feeling formed after development is low. The contrast between the greasy image and the surface of the support is low, resulting in poor so-called plate inspection, and there is a drawback that a new problem of hindering correction work such as erasure or retouching occurs. On the other hand, U.S. Pat. No. 3,458,311 discloses a negative in which a photosensitive layer comprising a photopolymerizable composition is provided on an aluminum support which is coated with a dibasic acid dye on a roughened aluminum plate which has been subjected to a hydrophilic treatment. Although a negative PS plate has been disclosed, a negative PS plate provided with a negative photosensitive resin composition containing a photosensitive diazo resin on this aluminum support has significantly reduced sensitivity,
It turned out that it could not be put to practical use at all.

[0008] US Patent No. 3,280,734 discloses
Anodize the Luminium plate and immediately afterwards moldable
-69 or an aqueous solution of Moldant Yellow 59
U.S. Pat. No. 2,714,00.0 on a treated aluminum support.
A diazo resin was provided as described in No. 66
A negative PS plate is disclosed, and further US Pat.
No. 7,555, anodized aluminum plate, then silicon
After treatment with aqueous solution of acid soda, colored with basic dye
Negative PS with diazo resin on aluminum support
Plates are disclosed, but these negative PS plates will eventually
Also aims to visualize oil-sensitive images obtained after development
The surface of the support is colored as
It is not intended to improve currency. this child
Means that the photosensitive layer is made of only a diazo resin,
The applied amount is about 10-30 mg / m ^TwoAnd extremely thin, this
Halation or irradiation in the case of such a thin photosensitive layer
Said that the tone reproducibility deteriorated because
The fact that the problem is not intrinsic
Supported. Further, specific examples are given in both of these patents.
Treated with a mordanting dye or basic dye
The aluminum plate is placed on a colored aluminum support.
Negative type provided with negative type photosensitive resin composition containing azo resin
PS plate, when prepress processing after storing for a long time,
Residual colors due to dye are likely to occur in non-image areas, and
Turned out to be a serious drawback of soiling
Was. In this way, the tone reproducibility is improved in the negative PS version.
Many attempts have been made, all of which have significant drawbacks.
there were. In addition, these technologies are applied to positive-type photosensitive lithographic printing plates.
A similar problem arises when used as a point loss prevention technology.
ing.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a positive photosensitive lithographic printing plate having a more faithful fine line reproducibility. Another object of the present invention is to provide a positive photosensitive lithographic printing plate which is less likely to have film edge marks and has excellent chemical resistance. Still another object of the present invention is to provide a positive photosensitive lithographic printing plate having good reproducibility of fine lines even when using a substrate having a large Ra which improves the image intensity.

[0010]

SUMMARY OF THE INVENTION The present invention provides a method for forming a surface of an aluminum plate which has been roughened and then anodized by 340-400.
A positive photosensitive composition having an undercoat layer of a dibasic acid dye having an absorption maximum wavelength at 450 nm and having two aromatic sulfonate skeletons, and directly containing o-quinonediazide on the undercoat layer This is a positive photosensitive lithographic printing plate obtained by coating a layer of an object. Hereinafter, the method for producing a positive photosensitive lithographic printing plate according to the present invention will be described in detail step by step.

The aluminum plate used in the present invention is selected from a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of a different element, or a plastic film on which aluminum is laminated or vapor-deposited.
The different elements contained in the aluminum alloy include silicon,
There are iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of the foreign element in the alloy is 10% by weight or less. Aluminum suitable for the present invention is pure aluminum. However, completely pure aluminum is difficult to produce due to refining technology, and therefore may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and the material is conventionally known and used, for example, JIS A
1050, JIS A 1100, JIS A 3103, JIS A 3005, etc. can be used as appropriate. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm.

The method of graining an aluminum plate according to the present invention is a method of electrochemical graining in an electrolytic solution of hydrochloric acid or nitric acid, a method of scratching an aluminum surface with a metal wire, a wire brush graining method, and a grinding ball. A mechanical graining method such as a ball grain method for graining the aluminum surface with an abrasive, a brush grain method for graining the surface with a nylon brush and an abrasive can be used, and any of the above graining methods alone or in combination Can also be used. The Ra of the surface of the grained aluminum is suitably in the range of 0.3 to 1.2 μm, and particularly when it is in the range of 0.6 to 1.0 μm, the undercoat layer of the dye according to the present invention is used. It is preferable because the effect of the provision is large, and the most preferable Ra is 0.64 to 0.8.
0 μm.

The grained aluminum plate is chemically etched with an acid or an alkali. When an acid is used as an etching agent, it takes time to destroy a fine structure, which is disadvantageous in industrially applying the present invention. However, it can be improved by using an alkali as an etching agent. Alkali agents suitably used in the present invention include caustic soda, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide, lithium hydroxide, and the like. The preferred ranges of concentration and temperature are 1 to 50, respectively. %, 20 to 100 ° C., and a condition in which the amount of aluminum dissolved is 5 to 20 g / m ³ . After etching, pickling is performed to remove dirt (smut) remaining on the surface. As the acid used, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borofluoric acid and the like are used. Particularly, in the smut removal treatment after the electrochemical surface roughening treatment, 50% as described in JP-A-53-12739 is preferably used.
A method of contacting with sulfuric acid of 15 to 65% by weight at a temperature of ~ 90 ° C and a method of alkali etching described in JP-B-48-28123 are used.

The aluminum alloy plate treated as described above can be used as a support for a lithographic printing plate, but may be subjected to further treatment such as anodizing treatment and chemical conversion treatment, if necessary. The anodizing treatment can be performed by a method conventionally performed in this field. More specifically, sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, etc., or a combination of two or more of these, when a direct current or an alternating current is applied to aluminum in an aqueous solution or non-aqueous solution, causes An anodic oxide film can be formed on the substrate. Anodizing conditions vary depending on the electrolytic solution used and thus cannot be determined unconditionally. Generally, however, the concentration of the electrolytic solution is 1 to 80%,
Liquid temperature 5 to 70 ° C, current density 0.5 to 60 amps / dm ² ,
The appropriate range is a voltage of 1 to 100 V and an electrolysis time of 10 to 100 seconds. Among these anodic oxide film treatments, in particular, the method of anodizing at a high current density in sulfuric acid used in the invention described in British Patent No. 1,412,768 and U.S. Pat. The method of anodic oxidation using phosphoric acid as an electrolytic bath described in the specification of Japanese Patent No. 511,661 is preferable.

After the anodic oxidation treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. U.S. Pat.No. 2,714,066 as the hydrophilization treatment used in the present invention,
There is an alkali metal silicate (e.g., sodium silicate aqueous solution) method as disclosed in 3,181,461, 3,280,734 and 3,902,734. In this method, the support is immersed or electrolytically treated in an aqueous solution of sodium silicate. In addition, Japanese Patent Publication No. 36-22
For example, a method of treating with potassium fluoride zirconate disclosed in JP-A-663 and polyvinylphosphonic acid as disclosed in U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689,272 is used. Further, after graining treatment and anodic oxidation, sealing treatment is also preferable. Such a sealing treatment is performed by immersion in hot water and a hot aqueous solution containing an inorganic salt or an organic salt, a steam bath, or the like.

The aluminum support thus obtained
It has an absorption maximum wavelength of 340 to 450 nm on the body and is aromatic
Dibasic acid dye having two aromatic sulfonate skeletons
Cloth. These dyes are water, organic solvents or water and organic
A method known as a mixed solution of solvents, for example, a dipping method
Coating by roll coating method, bar coating method
Can be 2-25 mg / m as coating amount^TwoIs good
3-20 mg / m ^TwoIs more preferred. 2mg / m^Two
If it is less, the effect of the present invention will not be sufficiently exhibited
And conversely, 25mg / m^TwoAs the number increases, chemical resistance deteriorates
I will be. Absorbs 340-450 nm used
Has maximum wavelength and two aromatic sulfonic acid skeletons
Examples of the dibasic acid dye include C.I. I. -Acid Yellow-
3 (structural formula (I)), C.I. I. -Acid Yellow-17
(Structural formula (II)), C.I. I. -Acid Yellow -38
(Structural formula (III)). I. -Acidi
Yellow 3 is the most preferable in terms of fine line reproducibility.

[0017]

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Color of non-image area after development (hereinafter referred to as residual color)
May be mixed with an organic compound for the purpose of reducing the amount of water. Examples of the organic compound include phosphonic acid having an amino group such as carboxymethylcellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, phenylphosphonic acid optionally having a substituent, naphthylphosphonic acid, alkylphosphonic acid, and glycerol. Phosphonic acids, organic phosphonic acids such as methylene diphosphonic acid and ethylene diphosphonic acid, phenylphosphoric acid which may have a substituent,
Organic phosphoric acids such as naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid, and optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acids such as alkylphosphinic acid and glycerophosphinic acid, glycine and β-alanine And a hydrochloride of an amine having a hydroxyl group, such as a hydrochloride of triethanolamine. These may be used as a mixture of two or more.

Representative examples of the o-quinonediazide compound used as the photosensitive compound of the positive photosensitive composition of the present invention include an o-naphthoquinonediazide compound.
The o-naphthoquinonediazide compound is disclosed in
An ester of 1,2-diazonaphthoquinone sulfonic acid chloride and a pyrogallol-acetone resin described in -28403 is preferred from the viewpoint of plate cleaner resistance. Other suitable orthoquinonediazide compounds include the 1,2-type compounds described in U.S. Pat. Nos. 3,046,120 and 3,188,210.
There is an ester of diazonaphthoquinone-5-sulfonic acid chloride with a phenol-formaldehyde resin, which is described in JP-A-2-96163, JP-A-2-96165, and JP-A-2-96661.
There are esters of 2-diazonaphthoquinone-4-sulfonic acid chloride with phenol-formaldehyde resin.
Other useful o-naphthoquinonediazide compounds include those reported and known in numerous patents. For example, JP-A-47-5303 and JP-A-48-5303
63802, 48-63803, 48-965
No. 75, No. 49-38701, No. 48-13354
No., JP-B-37-18015, 41-11222
No. 45-9610, No. 49-17481,
U.S. Pat.Nos. 2,797,213, 3,454,400, 3,54
No. 4,323, No. 3,573,917, No. 3,674,495, No.
3,785,825; British Patent Nos. 1,227,602; 1,251,34
No. 5, No. 1,267,005, No. 1,329,888, No. 1,33
No. 0,932, German Patent No. 854,890 and the like.

The particularly preferred o-naphthoquinonediazide compound in the present invention is a compound obtained by reacting a polyhydroxy compound having a molecular weight of 1,000 or less with 1,2-diazonaphthoquinonesulfonic acid chloride. Specific examples of such compounds are described in JP-A-51-139402,
No. 58-150948, No. 58-203434, No. 59-165053, No. 60-112445, No. 6
0-134235, 60-16043, 61
-118744, 62-10645, 62-1
Nos. 0646, 62-153950, 62-178
No. 562, No. 64-76047, U.S. Pat.
No. 9, No. 3,126,281, No. 3,130,047, No. 3,14
No. 8,983, No. 3,184,310, No. 3,188,210, No.
Examples described in each gazette or specification such as 4,639,406 can be mentioned.

In synthesizing these o-naphthoquinonediazide compounds, it is preferable to react 0.2 to 1.2 equivalents of 1,2-diazonaphthoquinonesulfonic acid chloride with respect to the hydroxyl group of the polyhydroxy compound. .3 ~
More preferably, the reaction is carried out at 1.0 equivalent. 1,2-diazonaphthoquinonesulfonic acid chloride includes 1,2-diazonaphthoquinonesulfonic acid chloride.
Diazonaphthoquinone-5-sulfonic acid chloride or 1,2-diazonaphthoquinone-4-sulfonic acid chloride can be used. The obtained o-naphthoquinonediazide compound is a mixture of various compounds having different positions and introduced amounts of 1,2-diazonaphthoquinonesulfonic acid ester groups, but all of the hydroxyl groups are converted to 1,2-diazonaphthoquinonesulfonic acid ester. The proportion of the compound in the mixture (content of the completely esterified compound) is preferably 5 mol% or more, more preferably 20 to 99 mol%.

The amount of these positive-acting photosensitive compounds (including the above combinations) in the photosensitive composition of the present invention is suitably from 10 to 50% by weight, more preferably from 15 to 50% by weight. 40% by weight. Although the o-quinonediazide compound alone constitutes the photosensitive layer, it is preferable to use a resin soluble in alkaline water as a binder together with this kind of resin. As such a resin soluble in alkaline water, there is a novolak resin having this property.
-Cresol formaldehyde resin, p-cresol formaldehyde resin, o-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, o- or m
-/ P- or m- / o-mixture) and cresol formaldehyde resins such as mixed formaldehyde resins. In addition, resol type phenol resins are also preferably used, and phenol / cresol (m
-, P-, o- or m- / p-, m- / o-). Mixed formaldehyde resins are preferred, and phenol resins described in JP-A-61-217034 are particularly preferred. .

Also, a phenol-modified xylene resin, polyhydroxystyrene, polyhalogenated hydroxystyrene, an acrylic resin containing a phenolic hydroxyl group as disclosed in JP-A-51-34711, and JP-A-2-866. Various alkali-soluble polymer compounds such as an acrylic resin having a sulfonamide group described in (1) and a urethane resin can also be used. These alkali-soluble polymer compounds have a weight average molecular weight of 50.
Those having a number average molecular weight of 0 to 20,000 and a number average molecular weight of 200 to 6,000 are preferred. Such alkali-soluble polymer compounds may be used alone or in combination of two or more.
It is used in an amount of up to 80% by weight of the total composition. Further, as described in U.S. Pat. No. 4,123,279, a condensate of formaldehyde with a phenol having an alkyl group having 3 to 8 carbon atoms as a substituent, such as a t-butylphenol formaldehyde resin or an octylphenol formaldehyde resin. It is preferable to use a combination of these in order to improve the oil sensitivity of the image. It is preferable to use a phenol (cresol) resin having less residual monomer components in view of environmental measures against odor. The amount of the residual monomer component is preferably less than 4.0% by weight in the coated photosensitive layer. Above that, the odor increases. When the content is less than 3.0% by weight, odor is almost eliminated, which is more preferable.

In the photosensitive composition of the present invention, it is preferable to add a cyclic acid anhydride, an organic acid or the like in order to increase the sensitivity. U.S. Pat.
115,128 Pat phthalic anhydride, as described in, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-oxy - [delta ⁴ - tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloro Maleic anhydride, α-phenyl maleic anhydride, succinic anhydride, pyromellitic anhydride and the like. Examples of the organic acids include sulfonic acids, sulfinic acids, alkyl sulfates, phosphonic acids, phosphinic acids, phosphoric esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755. Acids, and specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid Acid, adipic acid, p-toluic acid, 3,
4-dimethoxybenzoic acid, phthalic acid, terephthalic acid,
Examples thereof include 1,4-cyclohexene-2,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, and ascorbic acid. The proportion of the above-mentioned cyclic acid anhydrides and organic acids in the photosensitive composition is preferably from 0.05 to 15% by weight, more preferably from 0.1 to 5% by weight.

In the photosensitive composition of the present invention, a compound capable of generating an acidic substance by photolysis, such as an o-type compound described in JP-A-50-36209 (US Pat. No. 3,969,118). Naphthoquinonediazide-4-sulfonic acid halide, JP-A-53-36223 (= U.S. Pat.
0,671), trihalomethyl-2-pyrone and trihalomethyltriazine, and various o-types described in JP-A-55-62444 (= British Patent No. 2,038,801).
Naphthoquinonediazide compound, JP-A-55-77742
2-trihalomethyl-5-aryl-1,3,4-oxadiazole compound described in U.S. Pat. No. 4,279,982, and piperonyl triazine described in Japanese Patent Application No. 5-184147. Etc. can be added. These compounds can be used alone or as a mixture.
0.3 to 15% by weight is preferred.

As the color-changing agent used in the present invention, those which change from a colorless state to a colored state by the action of an acid generated at the time of photolysis of a compound which generates an acid by photolysis can be used. There are two types: those that have color and those that discolor or bleach. Representative examples of the color changing agent belonging to the former type include arylamines. Arylamines suitable for this purpose include simple arylamines such as primary and secondary aromatic amines, as well as so-called leuco dyes, examples of which include: Diphenylamine, dibenzylaniline, triphenylamine, diethylaniline, diphenyl-p-phenylenediamine, p-toluidine, 4,4'-biphenyldiamine,
o-chloroaniline, o-bromoaniline, 4-chloro-o-phenylenediamine, o-bromo-N, N-dimethylaniline, 1,2,3-triphenylguanidine,
Naphthylamine, diaminodiphenylmethane, aniline, 2,5-dichloroaniline, N-methyldiphenylamine, o-toluidine, p, p'-tetramethyldiaminodiphenylmethane, N, N-dimethyl-p-phenylenediamine, 1,2-dianilino Ethylene, p,
p ', p "-hexamethyltriaminotriphenylmethane, p, p'-tetramethyldiaminotriphenylmethane, p, p'-tetramethyldiaminodiphenylmethylimine, p, p', p" -triamino-o- Methyltriphenylmethane, p, p ', p "-triaminotriphenylcarbinol, p, p'-tetramethylaminodiphenyl-4-anilinonaphthylmethane, p, p', p"
-Triaminotriphenylmethane, p, p ', p "-hexapropyltriaminotriphenylmethane.

Examples of the discoloring agent which originally has a unique color and which discolors or decolorizes due to the photolysis product of the free radical generator include diphenylmethane, triphenylmethane, thiazine, and oxazine. System, xanthene system,
Various dyes such as anthraquinone-based, iminonaphthoquinone-based, azomethine-based, and azo-based dyes are effectively used. Examples of these are as follows. Brilliant Green, Eosin, Ethyl Violet, Erythrosin B,
Methyl green, crystal violet, basic fuchsin, phenolphthalein, 1,3-diphenyltriazine, alizarin red S, thymolphthalein, methyl violet 2B, quinaldine red, rose bengal, methanil yellow, thymol sulfophthalein, xylenol blue , Methyl orange, orange
IV, diphenylthiocarbazone, 2,7-dichlorofluorescein, paramethyl red, congo red, benzopurpurine 4B, α-naphthyl red, nile blue 2B, nile blue A, phenacetaline, methyl violet, malachite green, parafuchsin, oil Blue # 603 (manufactured by Orient Chemical Industry Co., Ltd.), Oil Pink # 312 (manufactured by Orient Chemical Industry Co., Ltd.), Oil Red 5B (manufactured by Orient Chemical Industry Co., Ltd.), Oil Scarlet # 308 [Orient Chemical Industry Co., Ltd. )
Oil Red OG [Orient Chemical Industry Co., Ltd.]
Oil Red RR [Orient Chemical Industry Co., Ltd.]
Oil Green # 502 (Orient Chemical Industry Co., Ltd.), Spiron Red BEH Special (Hodogaya Chemical Industry Co., Ltd.), Victoria Pure Blue BOH
[Hodogaya Chemical Industry Co., Ltd.], Victoria Pure Blue Naphthalenesulfonate, m-cresol purple, cresol red,

Rhodamine B, rhodamine 6G, fast acid violet R, sulforhodamine B, auramine, 4-p-diethylaminophenylimino naphthoquinone, 2-carboxyanilino-4-p-diethylaminophenyliminonaphthoquinone, 2-carbostearyl Amino-4-p-dihydroxyethyl-amino-phenyliminonaphthoquinone, p-methoxybenzoyl-
p'-diethylamino-o'-methylphenyliminoacetanilide, cyano-p-diethylaminophenyliminoacetanilide, 1-phenyl-3-methyl-4-
p-diethylaminophenylimino-5-pyrazolone,
1-β-naphthyl-4-p-diethylaminophenylimino-5-pyrazolone, 2,4-dinitro-5-chloro-2'-acetamino-4'-diethylamino-5'-
Methoxyazobenzene.

The leukotriphenylmethane dye among the color changing agents used in the present invention is generally easily oxidized. Therefore, when using these dyes, it is effective to include a certain kind of stabilizer. Examples of the stabilizer for this purpose include amines, zinc oxide and phenols described in U.S. Pat.No. 3,042,575, sulfur compounds described in U.S. Pat. No. 3,042,516, and alkali metal iodides described in U.S. Pat. No. 3,042,518. Compounds, organic acids, organic acid anhydrides described in US Pat. No. 3,082,086 and triaryl compounds of antimony, arsenic, bismuth and phosphorus described in US Pat. No. 3,377,167 are effective. It is preferable to add the discoloring agent in an amount of 0.3 to 5% by weight based on the whole composition. At 0.3% by weight or less, the image density is low, and at 5% by weight or more, the discoloring agent remains on the substrate after development. Further, in the photosensitive composition of the present invention, a nonionic surfactant such as that described in JP-A-62-251740 and JP-A-4-68355 is used in order to widen the development latitude. JP-A-59-121044, JP-A-4-13149
An amphoteric surfactant such as that described in JP-A No. 2-211 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan triolate, stearic acid monoglyceride, polyoxyethylene sorbitan monooleate, polyoxyethylene nonyl phenyl ether, and the like. Specific examples of the activator include alkyl di (aminoethyl) glycine, alkyl polyaminoethyl glycine hydrochloride, Amogen K (trade name, manufactured by Dai-ichi Kogyo Co., Ltd., N-tetradecyl-N, N-betaine type),
2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, Levon 15 (trade name, manufactured by Sanyo Chemical Co., Ltd., alkylimidazoline system) and the like. The proportion of the nonionic surfactant and the amphoteric surfactant in the photosensitive composition is preferably 0.05% to 15% by weight, more preferably 0.1% to 5% by weight.

The photosensitive lithographic printing plate of the present invention can be obtained by dissolving each of the above components in a solvent capable of dissolving and applying the solution to a support. As the solvent used here, cyclohexanone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, 1-methoxy-2
-Propanol, 1-methoxy-2-propyl acetate, toluene, ethyl acetate, methyl lactate, ethyl lactate,
Dimethyl sulfoxide, dimethylacetamide, dimethylformamide, water, N-methylpyrrolidone, tetrahydrofurfuryl alcohol, acetone, diacetone alcohol, methanol, ethanol, isopropanol,
There are diethylene glycol dimethyl ether and the like, and these solvents are used alone or as a mixture. And
The concentration (solid content) in the above components is 2 to 50% by weight. In addition, the amount of application varies depending on the application, but, for example, when it comes to photosensitive lithographic printing plates, generally, the solid content is 0.5 to 0.5.
3.0 g / m ² is preferred. As the amount of application decreases, the photosensitivity increases, but the physical properties of the photosensitive film deteriorate.

The photosensitive composition of the present invention may contain a surfactant for improving coating properties, for example, JP-A-62-17.
A fluorine-based surfactant as described in JP-A-0950 can be added. A preferable addition amount is 0.01 to 1% by weight of the total photosensitive composition, more preferably 0.05 to 1% by weight.
~ 0.5% by weight. The surface of the photosensitive layer provided as described above is preferably matted in order to shorten the time for evacuation during contact exposure using a vacuum printing frame and to prevent printing blur. Specifically, Japanese Patent Laid-Open No. 50-12580
No. 5, JP-B-57-6582 and JP-A-61-28986. A method of providing a mat layer as described in JP-B-57-65886 and JP-B-62-62337. And the like.

The developer for the photosensitive composition of the present invention comprises:
Alkaline aqueous solutions substantially free of organic solvents are preferred, specifically sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, Aqueous solutions such as ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, aqueous ammonia, etc. are suitable, and their concentration is 0.1 to 10% by weight. %, Preferably 0.5 to 5% by weight. Among these, a developer containing an alkali silicate such as potassium silicate, lithium silicate, and sodium silicate is preferable because stain during printing is less likely to occur, and the composition of the alkali silicate is [SiO ₂ ] / molar ratio. [M] = 0.5 to 2.5 (where [SiO ₂ ] and [M] indicate the molar concentration of SiO _{2 and} the molar concentration of the total alkali metal, respectively), and the SiO ₂ is defined as 0.5. 8
A developer containing 〜8% by weight is preferably used. In addition, water-soluble sulfites such as sodium sulfite, potassium sulfite, and magnesium sulfite, resorcin, methylresorcin, hydroquinone, and thiosalicylic acid can be added to the developer. The content of these compounds in the developer is preferably 0.002 to 4% by weight, and more preferably 0.01 to 1% by weight.

Further, in the developer, JP-A-50-5132
4, JP-A-59-84241 and JP-A-59-84241, and JP-A-59-75255, JP-A-60-111246 and JP-A-60-213943. JP-A-55-95946, by incorporating at least one nonionic surfactant as described in Japanese Patent Publications
As described in JP-A-56-142528, a polymer electrolyte is contained to enhance wettability to a photosensitive composition and development stability (development latitude). Are preferably used. The addition amount of such a surfactant is preferably 0.001 to 2% by weight, and particularly preferably 0.003 to 0.5% by weight. Further, as the alkali metal of the alkali silicate, it is preferable that potassium is contained in an amount of 20 mol% or more in all the alkali metals, since generation of insolubles in the developer is small, and more preferably 9
0 mol% or more, most preferably 100 mol% of potassium
Is the case. Further, the developing solution used in the present invention may contain some organic solvents such as alcohols and
Chelating agent described in JP-B-2, JP-B-1-30
An antifoaming agent such as a metal salt or an organic silane compound described in JP-A-139-139 may be added. Light sources used for exposure include a carbon arc lamp, a mercury lamp, a xenon lamp, a tungsten lamp, and a metal halide lamp.

The photosensitive lithographic printing plate of the present invention is disclosed in
JP-A-8002, JP-A-55-115045 and JP-A-59-15045.
It goes without saying that the plate-making process may be performed by the method described in each of the publications of No. 58431. That is, after the development processing,
A desensitization treatment after washing with water, a desensitization treatment as it is, a treatment with an aqueous solution containing an acid, or a treatment with an aqueous solution containing an acid may be followed by a desensitization treatment. Furthermore, in the development process of this type of photosensitive lithographic printing plate, the alkali aqueous solution is consumed depending on the processing amount, and the alkali concentration is reduced, or the alkali concentration is reduced by air due to long-time operation of the automatic developing solution. Although the processing capacity is reduced, the processing capacity may be restored by using a replenisher as described in JP-A-54-62004. In this case, it is preferable to replenish by the method described in U.S. Pat. No. 4,882,246. Further, the above-described plate making process is preferably performed by an automatic developing machine as described in JP-A-2-7054 and JP-A-2-32357.

In the case where the photosensitive lithographic printing plate of the present invention is subjected to image exposure, development, washing or rinsing, and unnecessary image portions are to be erased, it is described in JP-B-2-1293. It is preferable to use such an erasing liquid. Examples of the desensitized gum which is applied as required in the final step of the plate making process include JP-B-62-16834, JP-B-62-25118, JP-B-63-52600 and JP-A-6-52600.
Nos. 2-7595, 62-11693 and 62-83
What is described in each gazette of No. 194 is preferable. Furthermore, when the photosensitive lithographic printing plate of the present invention is subjected to image exposure, development, washing or rinsing, erasing if desired, and burning after washing with water, before burning, Japanese Patent Publication No. 61-2518 is used. And JP-A-55-28062, JP-A-62-31859, and JP-A-61-159655.

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

Examples 1 to 5 Comparative Examples 1 to 9 An aluminum plate having a thickness of 0.30 mm was used to convert a hair diameter of 0.57 to 0.72 mm.
400 mesh pumice by changing the pressure of nylon brush
Grained its surface while supplying tons of water suspension
After that, it was washed well with water. 70% in 10% sodium hydroxide
After immersion at 60 ° C for 60 seconds and etching, after washing with running water
20% HNO_ThreeAnd washed with water. This is V_A= 12.
1% nitric acid using a sinusoidal alternating current under 7V
160 coulomb / dm in aqueous solution^TwoElectrolysis with the amount of electricity at the anode
A roughening treatment was performed. Continue to 30% H_TwoSO_FourWater soluble
After immersion in liquid and desmutting at 55 ° C for 2 minutes, 20%
 H _TwoSO_FourCurrent density 2A / dm in aqueous solution^TwoThe thickness is 2.
7g / m^TwoThe substrate was prepared by anodizing such that
The undercoat liquid shown in Table 1 was applied to supports A and B having different Ras.
Was applied in combination. To the undercoated support
Apply and dry the following positive photosensitive liquid to form a positive lithographic printing plate.
Obtained. The coated amount of the photosensitive layer after drying is 1.7 g / m^Twoso
there were.

<Photosensitive solution>-Cresol formaldehyde novolak resin 2.10 g (meta / para ratio: 6: 4, weight average molecular weight 3000, number average molecular weight 1100, containing 0.7% of unreacted cresol)-p-normal octylphenol 0.02 g of formaldehyde resin (as described in U.S. Pat. No. 4,123,279) 0.10 g of tetrahydrophthalic anhydride 1.75 g of 1,2-diazonaphthoquinone-5-sulfonyl chloride and 0.75 g of pyrogallol- Esterified product with acetone resin (described in Example 1 of US Pat. No. 3,635,709) Triazine compound [Structural formula (IV) below] 0.04 g Naphthoquinone-1,2- Diazide-4-sulfonic acid 0.03 g chloride ・ Victoria pure blue naphthalene sulfonic acid 0.05 g ・ mega FAK F-177 (0.05 g of a fluorinated surfactant in methyl isobutyl ketone solution of 20% by weight, manufactured by Dainippon Ink and Chemicals, Inc.) ・ Hydroxymethylphenol compound [the following structural formula (V)] 0.07 g ・ Methyl ethyl ketone 30 .0g

After exposing these positive photosensitive printing plates with a 3 KW metal halide lamp from a distance of 70 cm,
Using an 8-fold dilution of P-4 (trade name: manufactured by Fuji Photo Film Co., Ltd.), automatic development (800 U: using an automatic development machine manufactured by Fuji Photo Film Co., Ltd.) was performed at 25 ° C. for 40 seconds.
The appropriate exposure time at this time is a point at which four steps are completely clear in a gray scale (manufactured by Fuji Photo Film Co., Ltd.) with a density difference of 0.15, and an exposure amount at which the film edge mark completely disappears (at this time, 5 Was clear.) The K value (line width: μm) of the Fogler film was adopted as a judgment of tone reproducibility under these plate making conditions. Also 4m ²
A test for residual color in a developer subjected to a 1 / liter process was also performed. Also, the chemical resistance of these printing plates shows how the image area is affected when dipped in an ultraplate cleaner for 10 minutes. Table 2 shows the results.

[0040]

[Table 1] ─────────────────────────────────── Undercoat agent and amount of undercoat Undercoat liquid composition Support Ha (Μm) (mg / m ² ) Amount of primer (g) in 100 g of water and 400 g of methanol実 施 Example 1 A 0.48 CI-Acid Yellow 3 (5) 0.125 2 A 〃 10 (10) 0.25 3 A 〃 〃 (20) 0.50 4 A 〃 CI-Acid Yellow 3 (5) 0.125 β -Alanine (10) 0.25 5 B 0.72 CI-Acid Yellow 3 (10) 0.25 6 A 0.48 CI-Acid Yellow 17 (10) 0.25 7 A 〃 CI-Acid Yellow 38 (10) 0.25 ──────── ─────────────────────────── Comparative Example 1 A 0.48 None ─ 2 A 〃 CI-Acid Yellow 25 (5) 0.125 3 A 〃 〃 (10) 0.25 4 A 〃 〃 (20) 0.50 5 A 〃 CI-A CId Yellow 29 (10) 0.25 6 A 〃 CI-Acid Yellow 76 (10) 0.25 7 A 〃 Compound (VI) (10) 0.25 8 B 0.72 None ９ 9 B 〃 CI-Acid Yellow 25 (10) 0.25 10 A 0.48 CI-Acid Yellow 23 (10) 0.25─────────────────────────────────── C.I. I. Acid Yellow 25, 29 and 76 are dyes described in JP-A-61-122649, and compound (VI) is a dye described in U.S. Pat. No. 3,458,311. Ha (10μR stylus)

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[Table 2] 値 Reproduction value of K value ────── ─────── Four-step clear image Chemical resistance required for four-step clear and five-step clear Remaining color strength Plate (Film (Film exposure time (min) Edge mark Edge mark (Second) available) None) ─ ────────────────────────────────── Example 1 12μ B 12μ C 40 20 AB 2 12μ A 12μ B 40 18 AB 3 10μ B 12μ A 45 15 AB 4 12μ B 12μ C 40 18 AB 5 12μ C 15μ B 40 18 AA 6 12μ A 15μ C 40 18 AB 7 12μ A 15μ C 40 18 AB ────────比較 Comparative Example 1 15μ C 20μ C 40 20 CB 2 12μ C 20μ A 45 20 BB 3 12μ B 15μ C 45 18 BB 4 12μ A 15μ B 40 15 BB 5 12μ B 20μ A 40 18 BB 6 12μ C 20μ A 40 18 BB 7 12μ A 12μ C 60 18 B B 8 20μ C 30μ C 40 20 CA 9 20μ B 30μ B 40 18 BA 10 12μ A 12μ C 40 18 CB ───────────────────────── ──────────

The value of the K value was the value of the thinnest line remaining on the plate. A, B, and C represent the rest of the line, where A represents completely remaining, B represents about half remaining, and C represents slightly remaining.
Therefore, it can be said that the smaller the value is, and the more the line is completely left, the smaller the point reduction effect is. The exposure time (seconds) required to make a 4-step clear indicates the sensitivity of the plate, and the shorter the exposure time, the higher the sensitivity.・ The chemical resistance is indicated by the time from immersion in an Ultraplate Cleaner (sold by Dainichi Seika) until the image is damaged. The residual color shows a bluish color in the non-image area after development, A has no bluish color, C has a lot of bluish color, and B shows an intermediate color. The image intensity indicates the ease with which traces are formed when the plate is rubbed with a handbag, A indicates no trace, C indicates a trace, and B indicates the middle. In Examples 2, 5, and 6, points were less likely to be reduced than in Comparative Examples 3, 5, and 6, and the residual color was also good. Examples 2, 6, and 7
In Example 2, the point is hardly reduced in Example 2. Example 1
3. It can be seen that when the amount of undercoat is increased as compared with Comparative Examples 2 to 4, the chemical resistance deteriorates. C. I. When Acid Yellow 3 is used, when the K value in a four-stage clear is 12 μA (Example 2: undercoating of 5 mg / m ² ), the chemical resistance is 18 minutes, whereas the C.I. I. -When Acid Yellow 25 is used, it is necessary to apply 20 mg / m ² to obtain 12 μ (A), and the chemical resistance is deteriorated. Also, C.I. I. -K value of 5-step clear (no film edge marks) and C.I. I. -Acid Yellow 25 has the same K value for the four-step clear (with film edge marks), so that C.I. I. -When Acid Yellow 3 was used, no film edge marks appeared and C.I. I. -Acid Yellow 3 is better. In Comparative Examples 1 and 8, when Ra is increased, the image intensity is increased, but the point loss is increased.
Comparing Example 5 with Comparative Example 9, C.I. I. -Acid Yellow 3 using C.I. I. -Acid Yellow 25
It shows more faithful reproducibility, and has a 5-stage clear K of Comparative Example 3.
Better than value reproduction. From the above, the dye of the present invention (especially CI-acid yellow 3) is disclosed in JP-A-61-122.
No. 649, which is better in terms of residual color. Example 2 shows almost the same point reduction as Comparative Example 7, but the exposure time required for four-step clearing is shorter in Example 2 and higher in sensitivity. From the above, U.S. Pat.
It can be seen that the sensitivity decreases when the yellow dye described in JP-A-8-311 is used.

As described above, according to the present invention, the present invention has no point loss, has excellent fine line reproducibility, hardly shows a film edge mark,
It can be seen that it is possible to provide a photosensitive lithographic printing plate having little residual color and excellent in chemical resistance and image strength.

Claims (3)

(57) [Claims] 1. An undercoat comprising a dibasic acid dye having an absorption maximum wavelength of 340 to 450 nm and having two aromatic sulfonic acid skeletons on a surface of a roughened and then anodized aluminum plate. A layer directly on the undercoat layer.
-A positive photosensitive lithographic printing plate comprising a layer of a positive photosensitive composition containing quinonediazide. 2. The method according to claim 1, wherein the acid dye is C.I. I. The positive photosensitive lithographic printing plate according to claim 1, which is Acid Yellow 3. 3. An aluminum plate which has been roughened and then anodized has a center line average surface roughness (Ra) of 0.6 μm to 1.0 μm.
The positive photosensitive lithographic printing plate according to claim 2, which has a thickness of 0 µm.