JPH08339088A - Positive photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE: To provide such a planographic printing plate that small dots can be stably and accurately reproduced from a dot-image original film comprising 300 or more lines per one inch or from an original film produced by FM screening, and that a printed material showing a good state for out-of-focus development and having no rough appearance can be obtd., and to provide a method to obtain a good printed material by using this planographic printing plate. CONSTITUTION: A positive-type photosensitive compsn. layer is formed by 0.5-2.0g/m<2> coating amt. in such a manner that the absorption intensity per 1μm film thickness for 400nm wavelength after exposure is 0.06-0.29. This layer is formed by coating the surface of an aluminum plate which is preliminarily roughened and anodically oxidized. Then a matting layer is formed thereon to obtain a printing plate. The obtd. printing plate is used to obtain a printed material from a dot-image original film comprising 300 or more lines per one inch and from an original film prepared by FM screening.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive-working photosensitive lithographic printing plate, and more specifically, a positive-working photosensitive composition having an absorption intensity at 400 nm after exposure to an aluminum support which has been previously roughened and anodized. A positive-working photosensitive lithographic printing plate having faithful reproducibility to an original image film without being burnt out or having a feeling of roughness, which is obtained by applying a layer of a product, and further applying a matte layer thereon. It is a thing. Further, a printed image that is more faithful to the original image than the original image film having a line number of 1 inch 300 lines or more and the original image film obtained by FM screening using the positive photosensitive lithographic printing plate Is about how to get.

[0002]

2. Description of the Related Art A positive-working photosensitive lithographic printing plate (hereinafter referred to as "positive-working PS plate") having a layer of a bodi-type photosensitive resin composition provided on an aluminum support which has been grained in advance and anodized. When exposed through a positive transparent original image, the solubility in a developing solution in the exposed portion 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 hydrophilic surface of is exposed, thus forming a positive image. in this case,
When the exposure amount is decreased to produce the minimum halftone dot, the light amount is insufficient because the light is scattered at the edge part of the film,
An unnecessary image in that portion is formed on the plate, and it is necessary to erase the image after development and erasing. Therefore, in recent years, a plate with more faithful halftone dot reproducibility has been desired.

US Pat. No. 3,891,516 discloses a dark steel gray steel obtained by graining an aluminum plate with a moist abrasive such as a slurry of pumice and then immediately anodizing in sulfuric acid. A positive PS plate using an aluminum support having a surface exhibiting a color tone has been proposed. However, since the surface of the aluminum support of the positive PS plate has a low reflectance from the ultraviolet region to the visible light region, the print-out image obtained during image exposure becomes difficult to see, and it is formed after development. In addition, the contrast between the oil-sensitive image and the surface of the support is low, so-called plate inspection is inferior, and there is a problem in that correction work such as erasing and writing is hindered.

As a photosensitive planographic printing plate for obtaining a printed matter faithful to the original image, Japanese Patent Publication No. 7-43533 discloses 400.
A method of coating a photosensitive layer having an absorption intensity of nm of 0.06 to 0.29 per 1 μm is described. However, in this method, when a standard original film having a line number of 150 lines and 175 lines is used, faithful halftone dot reproducibility can be obtained, but the printing blur is deteriorated and the printed matter has a rough feeling. Occurs. It is considered that these problems are due to less unevenness on the surface of the photosensitive layer. On the other hand, Japanese Patent Publication No. 7-435
When a matting agent is added to the photosensitive layer as described in Japanese Patent No. 33, the burning blur is improved, but the rough feeling is not improved at all.

Further, in recent years, in order to obtain a printed matter that is more faithful to the actual product, an original image film having a line number of 300 inches or more and an original image film obtained by FM screening have been used. However,
When these original films are used, individual points on the original film are much smaller than those on the standard original film described above, so there are many variations in the reproducibility of the points due to fluctuations in the light amount and uneven illumination, and it is difficult to rework. More and more. Also, it is difficult to obtain reproducibility faithful to the original picture. Japanese Patent Fair 7-4353
The method described in Japanese Patent No. 3 is effective in improving these, but the blurring and the feeling of roughness are more likely to occur than in the case of using an original image film having a line number of 1 inch 175 lines. As described in Japanese Patent Publication No. 7-43533, even if a matting agent is internally added to the photosensitive layer, there is little improvement in the burning blur and the rough feeling remains very bad.

On the other hand, Japanese Patent Publication Nos. 57-6582 and 6
As described in JP-A-1-28986 and JP-B-62-62337, when a matte amount is provided on a photosensitive layer having an absorption intensity of 400 nm of 0.06 or less per 1 μm, burning blurring is improved, Due to the large amount of diffused light, it is more difficult to obtain faithful reproducibility with respect to the original image as compared with the case without the matte layer. However, the absorption intensity at 400 nm is 1 μm
When the matte layer is provided on the photosensitive layer of 0.06 to 0.29, the burning blurring is eliminated and the reproducibility faithful to the original image can be obtained as compared with the case where the matting agent is added to the photosensitive layer. Even more surprisingly, a matting agent is used as a photosensitive layer not only when using an original film having a standard line number but also when using an original film having a line number of 1 inch 300 lines or more and an original film obtained by FM screening. It was found that the printed matter, which could not be overcome with the type that was internally added to, eliminates the feeling of roughness.

[0007]

Accordingly, the object of the present invention is stable not only when using a standard original film, but also when using an original film of halftone dots having a number of lines of 300 inches or more and an original film obtained by FM screening. Another object of the present invention is to provide a lithographic printing plate which reproduces small dots faithfully and faithfully, has good printed blur, and does not have a feeling of roughness, and a method for obtaining a good printed product using the same.

[0008]

The present inventors have completed the present invention as a result of various studies to achieve the above object. In the present invention, a layer of a positive photosensitive composition having an absorption intensity at 400 nm after exposure of 0.06 to 0.29 per 1 μm of film thickness is applied at a coating amount of 0.5 to 2.0 g / m ² and a rough surface. A positive-working photosensitive lithographic printing plate characterized by being formed on a surface of an anodized aluminum plate and further provided with a matte layer thereon, and in particular, a mesh having a number of lines of 1 inch 300 lines or more. It shows a greater effect in obtaining a printed matter than that obtained by dot original or FM screening.

First, the planographic printing plate according to the present invention will be described. Aluminum plates used in the present invention include pure aluminum and aluminum alloy plates. Various aluminum alloys can be used, such as silicon, copper, manganese, magnesium, chromium, zinc,
An alloy of aluminum with a metal such as lead, bismuth, or nickel is used. These compositions include some iron and titanium, as well as other negligible amounts of impurities.

Prior to graining the aluminum plate, if necessary, the surface rolling oil may be removed and the surface of the aluminum plate may be pretreated to expose a clean aluminum surface. For the former, solvents such as trichlene and surfactants are used. For the latter, a method using an alkali etching agent such as sodium hydroxide or potassium hydroxide is widely used. As the graining method that can be used in the present invention, any of mechanical, chemical and electrochemical methods is effective. Mechanical methods include a ball polishing method, a plast polishing method, and a brush polishing method in which a water-dispersed slurry of an abrasive such as pumice is rubbed with a nylon brush.The chemical method includes:
A method of immersing in a saturated aqueous solution of an aluminum salt of a mineral acid as described in JP-A-55-31187 is suitable, and as an electrochemical method, acidic electrolysis such as hydrochloric acid, nitric acid or a combination thereof is used. A method of alternating current electrolysis in a liquid is preferable. Among such roughening methods, Japanese Patent Laid-Open No.
The surface-roughening method combining mechanical surface-roughening and electrochemical surface-roughening as described in JP-A-5-137993 is preferable because the adhesion of the oil-sensitive image to the support is strong.

The grained aluminum plate is washed with water and chemically etched as necessary. The etching treatment liquid used in the present invention is usually selected from an aqueous solution of a base or an acid which dissolves aluminum. In this case, the etched surface must not form a coating different from aluminum derived from the etching solution component. Examples of preferable etching agents include sodium hydroxide as a basic substance,
Potassium hydroxide, trisodium phosphate, disodium phosphate, tripotassium phosphate, dipotassium phosphate, etc .; acidic substances include sulfuric acid, persulfuric acid, phosphoric acid, hydrochloric acid and salts thereof, but with an ionization tendency than aluminum Low-metals such as zinc, chromium, cobalt, nickel, and copper salts are not preferable because they form an unnecessary film on the etched surface. These etching agents have a dissolution rate of 0.3 g to 40 g / m of the aluminum or alloy to be used per one minute of immersion time, depending on the settings of use concentration and temperature.
^It is most preferable to carry out so as to be ² , but it may be above or below this. Etching is carried out by immersing the aluminum plate in the above-mentioned etching solution or by coating the aluminum plate with the etching solution, and the etching amount may be treated in the range of 0.1 to 10 g / m ^2. preferable. As the above-mentioned etching agent, it is desirable to use an aqueous solution of a base because of its high etching rate. In this case, smut is generated, and thus desmutting is usually performed. As the acid used for the desmutting treatment, nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borofluoric acid or the like is used.

Further, if desired, an anodizing treatment is performed in order to improve water retention and abrasion resistance of the surface. As the electrolyte used for anodizing the aluminum plate, any electrolyte that forms a porous oxide film can be used, and generally sulfuric acid, phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte. The treatment conditions for anodic oxidation cannot be unconditionally specified because it varies depending on the electrolyte used, but generally the concentration of the electrolyte is 1 to 80 wt% solution, the liquid temperature is 5 to 70 ° C, and the current density is 1 to 60 A / dm.
² , a voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. In the sulfuric acid method, the treatment is usually performed with a direct current, but it is also possible to use an alternating current. Sulfuric acid is used at a concentration of 5 to 30%, and in the temperature range of 20 to 60 ° C.
It is electrolyzed for 250 seconds. The electrolytic solution preferably contains aluminum ions. Further, the current density at this time is preferably 1 to 20 A / dm ² . In the case of the phosphoric acid method, the treatment is performed at a concentration of 5 to 50%, a temperature of 30 to 60 ° C., and a current density of 1 to 15 A / dm ² for 10 to 300 seconds. The amount of the anodized film is preferably 1.0 g / m ² or more, more preferably 2.0 to 6.0 g / m ^2.
It is in the range of ² . When the anodic oxide film is less than 1.0 g / m ² , printing durability is insufficient, or the non-image area of the planographic printing plate is easily scratched, and ink adheres to the scratched portion during printing. Scratch stains are likely to occur.

After the anodizing treatment, the aluminum surface is optionally subjected to a hydrophilic treatment. Examples of the hydrophilic treatment used in the present invention include US Pat. No. 2,714,0
No. 66, No. 3,181,461, No. 3,280,73
4 and 3,902,734, there are alkali metal silicate (eg sodium silicate aqueous solution) methods. In this method, the support is immersed or electrolyzed in an aqueous sodium silicate solution. In addition, potassium fluorozirconate disclosed in Japanese Patent Publication No. 36-22063 and U.S. Pat. Nos. 3,276,868, 4,153,461 and 4,689,272 are disclosed. For example, a method of treating with polyvinylidenesulfonic acid is used. It is also preferable that after the graining treatment and the anodic oxidation, the sealing treatment is performed. Such 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 plate is optionally provided with an organic undercoat layer before coating the photosensitive layer. Examples of the organic compound used in this organic undercoat layer include phosphonic acids having an amino group such as carboxymethyl cellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, phenylphosphonic acid which may have a substituent, and naphthyl. Organic phosphonic acids such as phosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphoric acid which may have a substituent, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid Phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acids such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and triethanolamine hydrochloride The hydroxy Although selected from a sulfonic acid, such as hydrochloric salts Tamol of amines having a group it may be used as a mixture of two or more.

This organic undercoat layer can be provided by the following method. That is, water or a solvent in which the above organic compound is dissolved in an organic solvent such as methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof is applied on an aluminum plate and dried to provide a method, and water or methanol, ethanol, methyl ethyl ketone, etc. In a solution prepared by dissolving the above organic compound in the organic solvent or a mixed solvent thereof, the aluminum plate is immersed to adsorb the above organic compound, and then washed with water or the like and dried to form an organic undercoat layer. Is the way. In the former method, a solution having a concentration of 0.005 to 10% by weight of the above organic compound can be applied by various methods. For example, any method such as bar coater coating, spin coating, spray coating, or curtain coating may be used. In the latter method, the concentration of the solution is 0.01 to 20% by weight, preferably 0.05.
Is about 5% by weight, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., the immersion time is 0.1 seconds to 20 minutes,
It is preferably 2 seconds to 1 minute. The pH of the solution used for this purpose may be adjusted with a basic substance such as ammonia, triethylamine, potassium hydroxide or the like, or an acidic substance such as hydrochloric acid, phosphoric acid or the like, and the solution may be used in the range of pH 1-12.
Further, a yellow dye may be added to improve the tone reproducibility of the photosensitive lithographic printing plate. The coating amount of the organic undercoat layer after drying is suitably ² to 200 mg / m ² , and preferably 5 to 100 mg / m ² . The above coating amount is 2 mg
If it is less than / m ² , sufficient printing durability cannot be obtained. The same applies when the amount is larger than 200 mg / m ² .

A layer of the positive-working photosensitive composition is provided on the thus treated aluminum support. The positive photosensitive composition used in the present invention is preferably a composition comprising an o-quinonediazide compound and an alkali-soluble resin. The photosensitive compound used in the present invention is not particularly limited, but an o-naphthoquinonediazide compound is preferable.
Moreover, the polyhydroxyphenyl compound suitable for white light safety described in Japanese Patent Publication No. 4-31104 can be used. The polyhydroxyphenyl compound is a condensate of pyrogallol and acetone described in US Pat. No. 3,635,709, and US Pat. No. 4,028,1.
11-terminated polyesters having hydroxy groups, homopolymers of p-hydroxystyrene as described in GB 1,494,043 or other copolymers thereof. Copolymers with the resulting monomers, copolymers of p-aminostyrene with other copolymerizable monomers as described in US Pat. No. 3,759,711, US Pat. No. 3,046, 1
Examples thereof include phenol-formaldehyde resin and cresol-formaldehyde resin described in No. 20 specification. In particular, when a condensate of pyrogallol and acetone is used, a photosensitive composition excellent in sensitivity and development latitude can be obtained.

When a polyhydroxyphenyl compound is used in the present invention, 1,2-naphthoquinone-2-diazide-5 is condensed with the polyhydroxyphenyl compound.
-Sulfonyl halide (A) and 1,2-naphthoquinone-
The 2-diazido-4-sulfonyl halides (B) may be used alone or in a fixed ratio. Other known o-naphthoquinonediazide compounds that can be used in the present invention are JP-A 47-5303 and 48-638.
02, 48-63803, 48-96575.
No. 49, No. 38-3801, No. 48-13354, No. 41-11222, No. 45-9610, No. 49.
Publications such as -17481, U.S. Pat. No. 2,797,21
No. 3, No. 3,454,400, No. 3,544,3
No. 23, No. 3,573,917, No. 3,674,
No. 495, No. 3,785,825, British Patent No. 1,
227,602, 1,251,345, 1,267,005, 1,329,888, 1,330,932, German Patent 854,890.
And those described in the respective specifications such as a number.

The amount of the photosensitive compound (preferably o-quinonediazide compound) in the photosensitive composition of the present invention is 1
It is 0 to 80% by weight, preferably 15 to 50% by weight, more preferably 20 to 35% by weight.

The o-naphthoquinonediazide compound used as the photosensitive compound alone constitutes the photosensitive layer, but it is preferable to use a resin soluble in alkaline water as a binder together with this type of resin. As such a resin soluble in alkaline water, there is a novolak resin having this property, and examples thereof include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, o-cresol formaldehyde resin, m- / p-mixture. Cresol formaldehyde resin, phenol / cresol (m
-, P-, o- or m- / p-, m- / o-mixture) mixed formaldehyde resins such as cresol formaldehyde resins. In addition, resol type phenol resins are also preferably used, and phenol / cresol (m-, p-, o- or m- / p-,
Mixed formaldehyde resins are preferable, and phenolic resins described in JP-A-61-217034 are particularly preferable.

Further, phenol-modified xylene resin, polyhydroxystyrene, polyhalogenated hydroxystyrene, an acrylic resin containing a phenolic hydroxyl group as disclosed in JP-A-51-34711, JP-A-2-866. It is possible to use various alkali-soluble polymer compounds such as an acrylic resin having a sulfonamide group described in No. 1, a urethane resin and the like. These alkali-soluble polymer compounds have a weight average molecular weight of 50.
Number average molecular weight of 0 to 100,000 and 200 to 60,0
00 is preferable.

The alkali-soluble polymer compound is 1
One kind or a combination of two or more kinds may be used, and it is used in an amount of 80% by weight or less, preferably 30 to 75% by weight, and more preferably 50 to 65% by weight of the total composition. Within this range, it is preferable in terms of developability and printing durability. Further, as described in U.S. Pat. No. 4,123,279, phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin. It is preferable to use a condensate of the above together in order to improve the oil sensitivity of the image.

The bodi type photosensitive composition used in the present invention has an absorption intensity at 400 nm after exposure of 0.
A compound is added so that the amount is from 06 to 0.29, preferably from 0.08 to 0.20, and more preferably from 0.10 to 0.18. Such compounds are UV-especially o-
Any ultraviolet absorber having an absorption in the absorption band of quinonediazide at 350 to 450 nm may be used. For example, yellow and orange oil-soluble dyes and yellow and orange basic dyes described in Dye Handbook, triazine compounds and oxydiazole compounds can be mentioned.
For example, as a yellow oil-soluble dye, Aizen Spilon Yellow G
RH [Hodogaya Chemical Co., Ltd.], Eisen Spyron
Yellow 3RH [Hodogaya Chemical Co., Ltd.], Eisen
Spyron Yellow-C-GNH [Hodogaya Chemical Co., Ltd.], Eisen Sott Brown-2 (Aize
n Sot Brown-2) [Hodogaya Chemical Co., Ltd.], Eisen Spyron Orange GHR [Hodogaya Chemical Co., Ltd.], Sumiprat Orange G [Sumitomo Chemical Co., Ltd.], Dialesin Yellow (Diaresi)
n Yellow) F [Mitsubishi Kasei Kogyo Co., Ltd.], Orient Oil Yellow
low) 3G [Orient Chemical Industry Co., Ltd.] Bali
Fast Yellow (Vali Fast Yellow)
w) # 3104 [Orient Chemical Industry Co., Ltd.] Bali
Fast Yellow (Vali Fast Yellow)
w) # 3105 [Orient Chemical Industry Co., Ltd.], Soldan Yellow GRN
[Chugai Kasei Co., Ltd.], as a yellow basic dye, Primoflavine 8G [Sumitomo Chemical Co., Ltd.], Aizen Auramine (Aizen Aur)
Amine) 0-125 [Hodogaya Chemical Co., Ltd.], Aizen Cathilon Yellow (Aizen Cathi)
lon Yellow) 3GLH [Hodogaya Chemical Co., Ltd.], Aizen Catillon Brilliant Yellow (Aizen Cathilon Brilliant)
t Yellow) 5GLH [Hodogaya Chemical Co., Ltd.], Aizen Catillon Yellow (Aizen)
Cathilon Yellow) GLH [Hodogaya Chemical Co., Ltd.], Eisen Carotene Orange GLH
[Hodogaya Chemical Co., Ltd.], Sumiacryl Yellow 3R [Sumitomo Chemical Co., Ltd.], Daiacrylic Supra Brilliant
Yellow (Diacryl Supra Brilli
ant Yellow) 2GL [Mitsubishi Kasei Kogyo Co., Ltd.], Diacryl Supra Yellow (Diac
ryl Supra Yellow) 5RL [Mitsubishi Kasei Kogyo Co., Ltd.], Eisen Catillon Yellow (Aiz
en Cathelon Yellow) 3RLH [Hodogaya Chemical Co., Ltd.] and the like.

Next, as a triazine compound, Japanese Patent Laid-Open No.
Any one having absorption at 400 nm as described in JP-A-58440 and JP-B-59-1281 may be used. Furthermore, as an oxadiazole-based compound, Japanese Patent Publication No.
-6096, JP-A-59-148784, JP-A-6
400 as described in 0-138539
Any material having absorption in nm may be used. Further, JP-A-6-
You may add the orange type compound as described in 285447 gazette. The amount of such a compound used is such that the absorption intensity at 400 nm after exposure is 0.06 or more, and is generally 0.1 to 15 in the total photosensitive composition.
It is preferably added by weight%. Among these compounds, Aizen spirone yellow 3RH, Aizen spirone yellow-C-GNH, Aizen sotto brown-2, Aizen spirone yellow GRH, JP-A-63-58440.
The compounds described in JP-B-59-1281 are particularly preferred. The above compounds may be used alone, but 2
You may use together more than one kind.

A combination of compounds having a low absorption intensity before exposure and an increased absorption intensity at 400 nm after exposure, for example, o-naphthoquinonediazide-4-sulfonic acid halogenide described in JP-A-50-36209. JP-A-53-36223, trihalomethyl-2-pyrone and trihalomethyltriazine, various o-naphthoquinonediazide compounds described in JP-A-55-62444, JP-A-55-77742. 2-trihalomethyl-5-aryl-1,3,4 described in
A compound such as an oxadiazole compound which generates an acidic substance upon exposure to light, and a PH indicator which interacts with the acidic substance to increase absorption at 400 nm,
Combinations with dyes can also be used. As such an example, those which turn yellow on the acidic side, such as Bromophenol Blue,
Tetrabromophenol Blue
ophenol Blue), bromochlorophenol blue (Bromochlorophenol Bl
ue), Bromocresol Green (Bromocr)
esol Green) and the like.

In any of the above methods, the absorption intensity at 400 nm is 1 μm after the exposure, that is, at the exposure amount higher than the minimum exposure amount at which the non-image area is eluted with the developing solution.
It may be 0.06 to 0.29, preferably 0.08 to 0.20, and more preferably 0.09 to 0.29.
It should be 0.18. Generally, a photosensitive layer having an exposure amount required to obtain a desired absorption intensity up to about 3 times the minimum exposure amount is useful, and a smaller exposure amount required to obtain a desired absorption intensity is more faithful. It is preferable because it gives good tone reproducibility. In the present specification, "absorption intensity" means 1
A transparent support having a thickness of 00 μm was coated with a photosensitive composition in a dry weight of 2.5 g / m ² and dried, and then an exposure amount of at least 10 times the minimum exposure amount was applied, and then the photosensitive composition was applied. It shows the absorption intensity at 400 nm measured with the unsupported transparent support as a control. The thickness of the photosensitive composition was measured as 1 μm = 1 g / m ² for convenience.

Cyclic acid anhydrides, phenols and organic acids are preferably added to the photosensitive composition of the present invention in order to enhance sensitivity. Examples of the cyclic acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride and 3,6-endooxy-Δ ⁴ -as described in U.S. Pat. No. 4,115,128.
Examples thereof include tetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride and pyromellitic anhydride. Examples of phenols include bisphenol A, p-nitrophenol, p-ethoxyphenol,
2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 4,4,4 "-trihydroxy-triphenylmethane, 4,4 ', 3", 4 " -Tetrahydroxy-3,5,3 ', 5'-tetramethyltriphenylmethane and the like.

As organic acids, there is disclosed in JP-A-60-8894.
2 and JP-A-2-96755, there are sulfonic acids, sulfinic acids, alkylsulfates, phosphonic acids, phosphinic acids, phosphoric acid esters, carboxylic acids and the like, and specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethylsulfate, phenylphosphonic acid,
Phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 1,4-cyclohexene-2,2- Examples thereof include dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, and ascorbic acid. The above cyclic acid anhydrides,
The proportion of phenols and organic acids in the photosensitive composition is preferably 0.05 to 15% by weight, more preferably 0.1 to 5% by weight.

Further, in the photosensitive composition of the present invention, in order to extend the latitude of development, JP-A-62-62
Nonionic surfactants such as those described in JP-A-251740 and JP-A-4-68355,
Amphoteric surfactants such as those described in JP-A-9-121044 and JP-A-4-13149 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene sorbitan monooleate, and polyoxyethylene nonylphenyl ether. Specific examples of the activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, and Amogen K (trade name, Dai-ichi Kogyo Co., Ltd.).
, N-tetradecyl-N, N-betaine type), 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, Levon 15 (trade name, Sanyo Kasei Co., Ltd., alkylimidazoline type), etc. Is mentioned. The proportion of the nonionic surfactant and amphoteric surfactant in the photosensitive composition is preferably 0.05 to 15% by weight, more preferably 0.1 to 5% by weight.

In the photosensitive composition of the present invention, a printout agent for obtaining a visible image immediately after exposure, a dye as an image colorant, and other fillers can be added. The dye that can be used in the present invention has a cation having a basic dye skeleton described in JP-A-5-313359 and a sulfonic acid group as the only exchange group, and has 1 to 3 hydroxyl groups. A basic dye composed of a salt with an organic anion having 10 or more carbon atoms can be mentioned. The amount added is 0.2 to 5% by weight of the total photosensitive composition.

Further, a compound which interacts with the dye described in JP-A-5-313359 to generate a photodecomposition product which changes the color tone, for example, JP-A-50-36209 (US Pat. No. 3,969,118). O-naphthoquinonediazide-4-sulfonic acid halogenide described in JP-A No. 6-58200.
3-362223 (US Pat. No. 4,160,671), trihalomethyl-2-pyrone and trihalomethyltrisidine, JP-A-55-62444 (US Pat.
38,801), various o-naphthoquinonediazide compounds described in JP-A-55-77742 (US Pat.
279,982), 2-trihalomethyl-5-.
An aryl 1,3,4-oxadiazole compound or the like can be added. These compounds can be used alone or in combination. 400n of these compounds
A compound having absorption in m may be used as the yellow dye.

As an image colorant, the above-mentioned JP-A-5-3 is used.
Other dyes can be used in addition to the dye described in Japanese Patent No. 13359. Suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes.
Specifically, Oil Green BG, Oil Blue BO
S, Oil Blue # 603, (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue BOH, Victoria Pure Blue NAPS, Ethyl Violet 6H
NAPS [above, Hodogaya Chemical Co., Ltd.], Rhodamine B
(C145170B), Malachite Green (C142
000), methylene blue (C152015) and the like.

The photosensitive lithographic printing plate according to the present invention can be obtained by dissolving the components of each of the above-mentioned photosensitive compositions in a solvent which dissolves the components and coating the solution on a support. As the solvent used here, γ-butyrolactone, ethylene dichloride, 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, dimethylsulfoxide, dimethylacetamide, dimethylformamide, water, N-methylpyrrolidone, tetrahydrofurfuryl alcohol, acetone, diacetone alcohol, methanol, ethanol,
There are isopropanol, diethylene glycol dimethyl ether and the like, and these solvents are used alone or in combination. And the concentration (solid content) in the above components is 2 to
50% by weight is suitable. 0.5g / m as coating amount
^{2 to} 1.3 g / m ² is preferable. If it is less than 0.5 g / m ² , printing durability is deteriorated. When it is more than 1.3 g / m ² , the sensitivity is remarkably lowered when the absorption of 400 nm in the photosensitive layer is increased like this system.

In the photosensitive layer according to the present invention, a surfactant for improving the coating method, for example, JP-A-62-170 is used.
A fluorinated surfactant as described in Japanese Patent Publication No. 950 can be added. The preferable addition amount is 0.01 to 1% by weight of the total photosensitive composition, more preferably 0.0
It is 5 to 0.5% by weight. With the lithographic printing plate obtained as described above, it is possible to obtain a printed matter that is faithful to the original image film, but the blurred image and the printed material have a poor feeling of roughness.
As a method for improving the burning blur, there is a method of making the surface of the photosensitive amount thus provided uneven. For example, JP
As described in JP-A-1-258255, there is a method in which particles of several μm are added to a photosensitive solution and the particles are applied. However, this method has a small effect of improving the burning blur and does not improve the feeling of roughness. .

However, for example, JP-A-50-12580.
No. 5, Japanese Patent Publication No. 57-6582, No. 61-28986
No. 62-62337, a method of forming a component having unevenness on the surface of a light amount is used to improve the burning blurring and further improve the rough feeling of the printed matter. Further, as described in JP-B-55-30619, when a matting layer contains a light absorbing agent having absorption in the photosensitive wavelength region of the photosensitive material, the feeling of burning blurring and roughening is further improved. In addition, an original image film having a line number of 300 inches or more and an original image film obtained by FM screening are more likely to be burnt out than the original image film having a line number of 1 inch 175 lines, and the printed matter tends to have a dull feeling. However, good printed matter can be obtained. The fine patterns provided on the surface of the photosensitive layer of the photosensitive printing plate as described above are preferably as follows. That is, the height of the coated portion is preferably in the range of 1 to 20 μm, particularly 2 to 10 μm, and the size (width) is 10 to 10000 μm, especially 2
The range of 0 to 200 μm is preferable. Also, the amount is 1-100
The number is 0 / mm ² , preferably 5 to 500 / mm ² .

The developer for the photosensitive lithographic printing plate of the present invention is preferably an alkaline aqueous solution containing substantially no organic solvent, specifically sodium silicate, potassium silicate,
Sodium hydroxide, potassium hydroxide, lithium hydroxide,
Aqueous solutions such as sodium phosphate tribasic, sodium phosphate dibasic, ammonium phosphate tribasic, ammonium phosphate dibasic, sodium metasilicate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, aqueous ammonia etc. It is suitable and added so that the concentration thereof is 0.1 to 10% by weight, preferably 0.5 to 5% by weight. Among these, potassium silicate, lithium silicate,
A developer containing an alkali silicate such as sodium silicate is preferable because stains are less likely to occur during printing, and the composition of the alkali silicate is [SiO ₂ ] / [M] = 0.5.
~ 2.5 (where [SiO ₂ ] and [M] are S
The molar concentrations of iO ₂ and total alkali metals are shown. And a developer containing 0.8 to 8% by weight of SiO ₂ is preferably used. Further, in the developer,
For example, water-soluble sulfites such as sodium sulfite, potassium sulfite, and magnesium sulfite, resorcin, methylresorcin, hydroquinone, and thiosalicylic acid can be added. The preferred content of these compounds in the developer is 0.002 to 4% by weight, preferably 0.01 to 1% by weight.

Further, in the developer, Japanese Patent Laid-Open No. 50-5132 is used.
4 and 59-84241, and anionic surfactants and amphoteric surfactants described in JP-A-59-75255, 60-111246 and 60-213943. By incorporating at least one of the nonionic surfactants described in JP-A-55-95946 or the like.
As described in JP-A-56-142528, by containing a polymer electrolyte, the wettability to a photosensitive composition is enhanced and the stability of development (development latitude) is enhanced. And can be preferably used. The amount of such a surfactant added 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 the total alkali metal since insoluble matter is less generated in the developing solution, more preferably 90 mol% or more, and most preferably 100% potassium.
This is the case of mol%. Further, the developing solution used in the present invention contains a small amount of an organic solvent such as alcohol or JP-A-58-19.
Chelating agent described in Japanese Patent No. 0952, Japanese Patent Publication No.
A defoaming agent such as a metal salt or an organic silane compound described in JP-A-30139 can 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-54 / 54.
-8002, 55-115045, 59-58
It goes without saying that plate-making processing may be carried out by the method described in each publication of No. 431. That is, after the development treatment, desensitizing treatment after washing with water, or desensitizing treatment as it is,
Alternatively, desensitization treatment may be performed after treatment with an acid-containing aqueous solution or after treatment with an acid-containing aqueous solution. Furthermore, in the developing step of this type of photosensitive lithographic printing plate, the aqueous alkali solution is consumed depending on the processing amount to reduce the alkali concentration, or the long-time operation after automatic development reduces the alkali concentration by air. Although the processing capacity decreases, at that time, the processing capacity may be recovered by using a replenisher as described in JP-A-54-62004. In this case, it is preferable to replenish by the method described in US Pat. No. 4,882,246. The plate-making process as described above is preferably carried out by an automatic processor as described in JP-A-2-7054 and JP-A-2-32357. Further, when the photosensitive lithographic printing plate of the present invention is imagewise exposed, developed, washed with water or rinsed and then the unnecessary image portion is erased, it is described in JP-B-2-13293. It is preferable to use such an erasing liquid. Further, as the desensitizing gum which is optionally applied in the final step of the plate making step, JP-B Nos. 62-16834 and 62-25 are used.
118, 63-52600, JP-A-62-759.
No. 5, 62-11693, and 62-83194 are preferable. Furthermore, when the photosensitive lithographic printing plate of the present invention is imagewise exposed, developed, washed with water or rinsed, erased if desired, and burned after washing with water, JP-B-61-
No. 2518, No. 55-28062, and JP-A No. 62-31.
It is preferable to treat with a leveling solution as described in each of the publications of No. 859 and No. 61-159655.

[0038]

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

Examples 1 and 2 and Comparative Examples 1 to 7 An aluminum plate having a thickness of 0.30 mm was used as a nylon brush.
Surface of 400 mesh Bumistone water suspension
After being grained, it was thoroughly washed with water. 10% sodium hydroxide
Etched by immersion in thorium at 70 ° C for 60 seconds
20% HNO after washing with running water₃Neutralized and washed with water
It was This is an alternating wave of sine wave under the condition of VA = 12.7V.
260 coulomb / d in 1% nitric acid aqueous solution
m²Electrolytic surface roughening treatment was performed with the amount of electricity at the time of the anode. The table
When the surface roughness was measured, it was 0.55μ (R_aDisplay)
It was. Continued 30% H₂SO_FourImmersion in aqueous solution
And then desmut at 55 ° C for 2 minutes, then 20% H₂SO_Four
Current density 2 A / dm in aqueous solution ²Thickness is 1.6
g / m²Was anodized to prepare a substrate. This
The undercoat liquid of the following composition on the surface of the substrate treated as
(A) was applied and dried at 80 ° C. for 30 seconds. Cover after drying
Coverage is 10 mg / m²Met.

Undercoating liquid (A) β-alanine 0.05 g Triethanolamine hydrochloride 0.05 g Methanol 40 g Pure water 60 g Thus, the substrate (I) was prepared. Next, 25 ml of the following photosensitive solution was coated on this substrate (I) by rod coating.
/ M ^{2 and was} dried at 100 ° C for 1 minute to obtain a positive photosensitive lithographic printing plate. The applied amount after drying is about 1.0 g / m ^2.
Met.

[Photosensitive Solution] Esterified product of 1,2-diazonaphthoquinone-5-sulfonyl chloride and pyrogallol-acetone resin (described in Example 1 of US Pat. No. 3,635,709). ) 0.90 g Cresol-formaldehyde novolak resin (meta-para ratio: 6 to 4, weight average molecular weight 3,000, number average molecular weight 1,000, containing 0.7% of unreacted cresol) 1.60 g m-cresol -Formaldehyde novolac resin (weight average molecular weight 1,700, number average molecular weight 600, containing 1% of unreacted cresol) 0.3 g poly [N- (p-aminosulfonylphenyl) acryl amide-co-normal butyl acrylate- Co-diethylene glycol monomethyl ether methacrylate] (Mole of each monomer Is 40:40:20 in order, weight average molecular weight 40,000, number average molecular weight 20,000) 0.2 g Eisenspiron Yellow 3RH Table-1 (ASY-3RH Hodogaya Chemical Co., Ltd.) Particle size 4 μm Polyethylene particles Table- 1 p-Normal octylphenol-formaldehyde resin 0.02 g (described in U.S. Pat. No. 4,123,279) Naphthoquinone diazide-1,2-diazide-4-sulfonic acid chloride 0.01 g Tetrahydrophthalic anhydride Acid 0.02 g Benzoic acid 0.02 g Compounds described in JP-A-63-58440 Table-1 N- (1,2-naphthoquinone-2-diazide-4-sulfonyloxy) -cyclohexane-1,2-dicarboxylic acid imide Pair of 0.01g Victoria Pure Blue BOH [Hodogaya Chemical Co., Ltd.] Dye in which anion is changed to 1-naphthalene sulfonic acid 0.10 g Megafac F-176 (Fluorine surfactant manufactured by Dainippon Ink and Chemicals, Inc.) 0.01 g Methyl ethyl ketone 55 g Plate No. thus coated No. 1 to 9
According to the method described in JP-B No. 61-28986, Example 1, on the photosensitive layers of 7, 8, and 9 (methyl methacrylate / ethyl acrylate / sodium acrylate = 6
8/20/12) aqueous copolymer solution 100 g
A mat layer was provided by dissolving 0.1 g of Tolazine and electrostatically spraying.

[0042]

[Table 1]

The photosensitive lithographic printing plate thus prepared was placed in a vacuum baking frame to prepare a transparent positive film (175 lines / inch halftone dot original film, 500 lines / inch halftone original image film, 14 μdots). FM fog original film) was exposed from a distance of 1 m by a metal halide lamp of 3 kw so that the fogula PMSK value became 8 μ, and then a SiO ₂ / Na ₂ O molar ratio of sodium silicate of 1.74 was used as a developing solution. Fuji Photo Film Co., Ltd. FP-2W (1: 1) was used as a finisher solution of a 5.26% aqueous solution (pH = 12.7), Fuji Photo Film Co., Ltd. automatic processor Stablon 900D.
Processed through. After leaving this lithographic printing plate for 1 day, the printing was evaluated. The printing machine is Heidelberg KOR-D,
The fountain solution is EU-3 (1:10 manufactured by Fuji Photo Film Co., Ltd.).
0) and the ink used was Mark Five New Ink manufactured by Toyo Ink Co., Ltd. Table 2 shows the results.

[0044]

[Table 2]

To obtain a printed matter which is faithful to the original image and has no burning blur or roughness by setting the absorbance per 1 μm at 400 nm after exposure of the photosensitive layer to 0.06 or more and further providing a mat on the photosensitive layer. I was able to. Further, in Example 2 in which the absorption intensity was increased, a faithful printed matter was obtained even with a halftone original image of 500 lines / inch and an FM screen original image of 14 μdots as compared with Example 1.

[0046]

INDUSTRIAL APPLICABILITY The present invention stably and faithfully reproduces small dots even when an original image film having halftone dots having a line number of 300 inches or more and an original film obtained by FM screening are used. Further, it is possible to provide a photosensitive lithographic printing plate which can obtain a printed matter without a burning blur and a feeling of roughness.

Claims (2)

[Claims] 1. A layer of a positive-type photosensitive composition having an absorption intensity at 400 nm after exposure of 0.06 to 0.29 per 1 μm of film thickness is coated at 0.5 to 2.0 g / m ² and rough. Apply to the surface of an aluminum plate that has been surfaced and then anodized,
A positive photosensitive lithographic printing plate characterized by further having a matte layer formed thereon. 2. A method for obtaining a printed matter using the positive-working photosensitive lithographic printing plate according to claim 1 from a halftone dot original film having a line number of 300 inches or more and an original film obtained by FM screening.