JPS62275267A - Photosensitive lithographic plate having improved ink sticking property and developing property - Google Patents

Abstract

PURPOSE:To obtain a photosensitive lithographic plate which can develop a greater area with a small amount of developer and has ink sticking property, specially, after plate replacement (plate replacement aptitude) improved by applying a photosensitive layer on a base in a specific surface shape to specific film thickness. CONSTITUTION:The photosensitive lithographic plate is formed by coating the aluminum base with a photosensitive compound, the aluminum base has a rough surface whose noncavity rate (tpmi) is <=500% by an Abbot load curve at depth three times center line mean roughness (Ra), the photosensitive compound is applied on the base to <=14mg/dm<2>. The noncavity ratio (tpmi) is the ratio of the measured length (l) of a roughness profile R and an abutting surface formed by a cutting line of cutting depth (c). The center line mean roughness (Ra) of the surface of a base material in use is preferably 0.1-2.0mum and more preferably 0.2-1.5mum and, specially, when it is 0.3-0.9mum, it is most preferable in consideration of water retentivity.

Description

Detailed Description of the Invention 3 Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a photosensitive lithographic printing plate in which a photosensitive composition is coated on an aluminum support, and more specifically, This invention relates to an NFC-sensitive lithographic printing plate with improved ink receptivity and developability.

[Conventional technology]

A lithographic printing plate is composed of an oil-sensitive image area and a hydrophilic non-image area, and when used, it is moistened with water so that the non-image area is well wetted with this water and the image area is designed to repel this water. The subsequent oil-sensitive ink adheres only to the image area, and this is transferred to the object to be printed. Therefore, in order to obtain good printed matter, the image area must have good oil sensitivity and the non-image area must have good hydrophilicity.

A lithographic printing plate is widely produced from a photosensitive lithographic printing plate (PS plate) having a photosensitive layer on a support.

A lithographic printing plate is obtained by exposing the photosensitive layer of the photosensitive printing plate according to the original and removing the photosensitive layer in the non-image area with a developer. After applying liquid and drying (gumming), it is attached to a printing machine and used.

2. Description of the Related Art Photosensitive lithographic printing plates are generally developed using an automatic developing machine. At this time, the developer is stored in the tank of the automatic processor and used repeatedly, and as the plate is developed, its developing ability decreases until it becomes impossible to develop.

In recent years, from the viewpoint of pollution, it has been desired to develop more plates with less developer and to increase processing capacity.

One solution to this problem is to reduce the thickness of the photosensitive layer. By reducing the thickness of the photosensitive layer, the developer can penetrate into the photosensitive layer quickly.
It is easy to see that the developability is improved and the amount of the photosensitive layer eluted into the developer is reduced, thereby reducing the activity of the developer.

However, this method has the following disadvantages.

The aluminum support of a photosensitive lithographic printing plate is roughened (grained) to make the p1 sensitive layer thinner in order to improve its hydrophilicity, water retention, or adhesion to the photosensitive layer. , the tips of the grains tend to be exposed on the surface, the oil sensitivity of the image area tends to be insufficient, and the applied gum liquid is removed at the start of printing, resulting in ink build-up. bad. This is especially noticeable when using the developed Fi plate (a plate that has been used once for printing is removed from the ink, gummed, and stored for several days to several months).

As a means to improve ink deposition at the start of printing,
Techniques have been disclosed in which various compounds having hydrophobic groups and having affinity for printing inks are added to photosensitive compositions, or techniques in which the surface of the photosensitive layer is rendered lipophilic. for example,
JP-A-50-125806 discloses a technique in which a highly lipophilic novolac-type t-butylphenol-formaldehyde resin is contained in a photosensitive layer composed of O-quinonediazide and a novolak-type cresol-formaldehyde resin, JP-A-55-1989. No. 527 discloses a technique in which a polymer compound that is lipophilic and has poor compatibility with the main polymer compound is added to create a layer structure that is highly lipophilic on the surface.

[Problem that the invention seeks to solve]

However, although these techniques are effective in improving ink adhesion at the start of printing, their effectiveness is limited due to the fact that the oil-sensitive components on the surface are removed during printing. Not enough.

The purpose of the present invention is to solve the above-mentioned drawbacks, to develop a large area with a small amount of developer, and to improve ink receptivity, especially ink receptivity after plate placement (plate suitability). An object of the present invention is to provide an improved photosensitive lithographic printing plate.

[Means for solving problems]

To summarize the present invention, the present invention relates to a photosensitive lithographic printing plate, and the invention relates to a photosensitive lithographic printing plate in which a photosensitive composition is coated on an aluminum support. Abbott load-specific non-porosity (tpmi) at a depth three times the average roughness (Ra)
) has a rough surface of 50% or more, and the nuclear sensitive composition has a rough surface of 50% or more,
It is characterized in that it is coated on the support at a rate of 14η/dm2 or less.

As a result of extensive research, the present inventors have discovered that the above object can be achieved by coating a photosensitive layer with a specific thickness on a support with a specific surface shape,
This completes the present invention.

In the present invention, the above-mentioned non-porosity (tpmi) is the ratio of the measured length Am of the roughness profile alone to the length of the contact surface created by the cutting line of the cut lT depth C, as shown in Fig. 1. 1m5Ll, L2, L3... is determined by the following formula.

The reference line is a straight line parallel to the center line obtained by the filter and touching the peak of the roughness profile.

The value of tpmi in C=RaX3 is 50 or more,
It is preferably 60 or more, more preferably 65 or more.

The rough profile R of the surface of the base material mentioned above is the German standard roughness profile R when the surface roughness is measured using a stylus type surface roughness meter.
It is defined by the M-system shown in 4768,
A curve that represents the difference between the traced profile and the center line as a reference line.

In addition, the centerline average roughness (Ra) of the surface of the material used in the present invention is preferably 1 to 2.0 μm, more preferably 02 to 1.5 μm, and especially CL3
The case of ~CL9 μm is most preferable in terms of water retention. Here, the center line average roughness (Ra) is the German standard DIN
4768, it is the arithmetic mean of the absolute values of the distances from the center line of the roughness profile to each point on the profile. The axis is the point on the roughness profile (x, y)
When expressed as , it is expressed in units of Ra@f'e μm, which is determined by the following formula for the measured length μm.

The above center line average roughness (Ra), non-porosity (tp
mi) is, for example, a stylus type surface roughness meter manufactured by Pθrthen, a belt meter (Perthom), etc.
eter) Can be measured at 85P.

Aluminum supports used in the present invention include (c) pure aluminum or aluminum alloy plates or foils, composite materials made by laminating foils with other metals, paper, plastics, etc., and bath-melted aluminum plating on metal plates such as steel plates. A plate having an aluminum layer or the like is suitable. Various aluminum alloys can be used, such as silicon, iron, copper,
Alloys with metals such as manganese, magnesium, chromium, zinc, lead, bismuth, and nickel are used.

A support having a rough surface fc having the above characteristics can be obtained by appropriately selecting and combining the conditions of polishing treatment and further anodic oxidation treatment.

As the polishing method, various methods can be applied, such as ball polishing, brush polishing, chemical polishing, electrolytic polishing, liquid honing, puff polishing, and combinations thereof. Abrasives used in mechanical polishing include alumina,
Examples include silicon carbide, chromium oxide, red iron, tungsten carbide, boron carbide, sand, silica, and steel balls.

Specifically, an aluminum alloy plate (material: 1100, etc.) was lightly surface-treated using a 1-10% caustic soda solution to remove the oxidized layer, adhering oils, and contaminants, and then polished with a nylon brush or the like. Brush polishing is performed using the above-mentioned abrasive material such as abrasive sand to roughen the surface.

Etching by electrolysis includes hydrochloric acid, citric acid, nitric acid, boric acid, oxalic acid, or a mixture thereof.
-10% water bath solution, an applied voltage of 10 to 100 V, a current density of 1,100 A/dm'', a bath temperature of 10 to 50 DEG C., and an electrolysis time of 5 to 500 seconds.

Particularly preferred are baths based on nitric acid or hydrochloric acid.

When performing polishing treatment, it is desirable to degrease and clean the surface in advance. Examples of degreasing include solvent degreasing, which uses petroleum-based solvents or chlorinated hydrocarbons such as trichloroethylene and chloroethylene to remove stains, and nonionic surfactants and bath agents such as trichlorethylene and kerosene. Examples include emulsion degreasing using a solution emulsified with water, alkaline degreasing using boiling in a treatment solution containing an alkaline chemical, and electrolytic degreasing.

Since smut is generated on the surface of a roughened substrate, it is desirable to remove the smut by etching the surface with acid or alkali.

As the acid, sulfuric acid, phosphoric acid, hydrofluoric acid, nitric acid, hydrochloric acid, etc. are used.

As the alkali, sodium hydroxide, potassium hydroxide, tribasic sodium phosphate, tribasic potassium phosphate, sodium aluminate, sodium metasilicate, sodium carbonate, etc. are used.

Next, the aluminum plate is anodized.

The anodizing treatment is carried out by passing a direct or alternating current through aluminum in an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid, chromic acid, etc., alone or in combination. At this time! The concentration of the layer liquid is 1 to 70%, the liquid temperature is 10 to 65°C, the current density is 1 to 6 CI A/dm', and the applied voltage is 1 to 10.
Select from the range of 0V and electrolysis time of 10 seconds to 10 minutes.

In particular, anodizing in phosphoric acid or an electrolyte containing phosphoric acid as a main component provides good storage stability, printing durability, and chemical resistance (stability against chemicals used during printing, such as plate cleaners, etc.). Give results. For example, the aluminum plate is 10 to 50% by weight, preferably 20 to 40% by weight.
in an aqueous solution containing phosphoric acid, or in an aqueous solution containing a mixed acid of such phosphoric acid and another acid, such as sulfuric acid, oxalic acid, etc., in an amount of 25% by weight or less, preferably 10% by weight or less of the total acid,
At a bath temperature of 10 to 50°C, preferably 25 to 45°C,
, @10 A/dm to degree α2”, preferably 1 to 7
A/dnt” for 10 seconds to 10 minutes, preferably fi, 2
The average bore diameter of the anodized layer obtained is 200-900, preferably 300-? OOA
.

Particularly preferable trenches are 400 to 900A, and the bore density is loo.
~1,000 pieces/μm2, preferably 100-50
0 pieces/Jim", particularly preferably 100 to 350 pieces/μ-, is used.

The anodic oxide film t has a rating of 5 to 5 in terms of abrasion resistance in non-image areas and adhesion with the photosensitive layer, that is, printing durability and chemical resistance.
35mq/13x" is preferable, 8-30q7'a-
is even more preferable.

The anodized aluminum plate is usually further heated at 10 to 100°C in water or a weak acid or weak alkali aqueous solution.
Processing is performed under conditions ranging from 10 to 600 seconds. After that, a hydrophilic treatment is performed.

Examples of the hydrophilic treatment include hot water sealing and sodium silicate treatment, but sodium silicate treatment is preferred from the viewpoint of adhesiveness and developability. The conditions for sodium silicate treatment are:
~ 5% metasilicate in a sodium bath solution to a temperature of 50°C at 95°C.
℃ for 10 seconds to 5 minutes. Preferably,
Thereafter, it is treated by immersing it in water at 60° C. to 100° C. for 10 seconds to 5 minutes.

The photosensitive layer coated on the above support is most suitably one containing a lipophilic polymer compound and a diazo resin as main components, and the coating weight is 1419/d- or less, preferably 6
'9/dm' to 12119/d-.

The diazo resin is preferably a condensation product of substituted or unsubstituted p-diazodiphenylamine and aldehydes, and from the viewpoint of storage stability, the anion is PF or a halogenated Lewis acid such as BF4, and particularly General formula below■
A resin represented by the formula and where n is 5 or more is 2
A diazo resin containing 0 molti or more, preferably 20 to 60 molti is preferred.

(In the formula, Hl, R2 and R"Vi represent hydrogen, an alkyl group or an alkoxy group, and R represents hydrogen, an alkyl group or ij
(represents a phenyl group, X represents PF or BF4, and n represents a number from 1 to 200). You can also use some.

As the lipophilic polymer compound, a lipophilic polymer compound having a hydroxyl group is suitable from the viewpoint of storage stability. The lipophilic polymer compounds having hydroxyl groups used for this purpose include, for example, monomers such as acrylamides, methacrylamides, acrylic esters, or methacrylic esters having hydroxyl groups as shown below. Examples include copolymers containing structural units having a molecular weight of usually 20,000 to 200,000.

(1) Monomers having aromatic hydroxyl groups, such as N-(
4-hydroxyphenyl)acrylamide or 1jN-(
4-hydroxyphenyl) methacrylamide, o-, m
-, p-hydroxystyrene, o-, m-, p-hydroxyphenyl-acrylate or methacrylate (2)
Monomers having aliphatic hydroxyl groups, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, are copolymerized with other monomers such as (1) α, β-unsaturated monomers such as acrylic acid, methacrylic acid, maleic anhydride, etc. Carboxylic acid (2) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, dichloroethyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, N -(wL-converted) alkyl acrylate such as dimethylaminoethyl acrylate (3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate,
amyl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate, glycidyl methacrylate,
(replacement) of N-dimethylaminoethyl methacrylate, etc.
Alkyl methacrylate (4) Acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-
Acrylamides or methacrylamides such as hydroxyethyl acrylamide, N-phenylacrylamide, N-nitrophenyl acrylamide, N-ethyl-N-phenylacrylamide (51 ethyl vinyl ether, 2-chloroethyl vinyl ether, droxyethyl vinyl ether, propyl vinyl ether, Vinyl ethers such as phtyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether (6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate, and vinyl benzoate (7) Styrene, α-methylstyrene, methylstyrene, chloro Styrenes such as methylstyrene (8) Vinyl ketones such as methylvinylketone, ethylvinylketobebrovir vinylketone, and phenylvinylketone (9) Olefins such as ethylene, flopylene, inftylene, phtadiene, imprene, etc.C1ON-vinylpyrrolidone, Examples include N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylatetrile, etc., but any other monomer that can be copolymerized with a hydroxyl group-containing monomer may be used, and the present invention is not limited thereto. In addition, polyvinyl butyral resin, polyamide resin, polyamide resin, epoxy resin, novolak resin, natural resin, etc. may be added as required.

The lipophilic polymer compound having a hydroxyl group used in the present invention is usually 40 to 99% by weight in the solid content of the photosensitive composition.
, preferably 50 to 95% by weight. The diazo resin is usually contained in an amount of 1 to 60% by weight, preferably 3 to 30% by weight.

The following known additives can be added to the photosensitive composition of the present invention in order to further improve its performance.

(1) Dye for the purpose of visualizing images (
2) Fluorine surfactants and alkyl ethers to improve coating properties (3) Plasticizers to impart flexibility and abrasion resistance to the coating film (4) Sensitizers (5) Stabilizers The amount of addition is generally 101 to 30% by weight based on the total solid content! #,%.

The developer used in the development of the photosensitive lithographic printing plate according to the present invention may be any known developer, but the following are preferred. That is, the developer for developing the gI-based printing plate according to the present invention may be water or an aqueous solution containing a fi-specific organic solvent and/or an alkaline agent.

Here, the specific organic solvent is one that can dissolve or swell the non-exposed area (non-image area) of the above-mentioned photosensitive composition layer when contained in the developer, and that is resistant to water at room temperature (20°C). Refers to an organic solvent having a solubility of 10% by weight or less.

Such organic solvents only need to have the above-mentioned characteristics, and are not limited to the following, examples of which include ethyl acetate, propyl acetate, and acetic acid. Carboxylic acid esters such as butyl, amyl acetate, benzyl acetate, ethylene glycol monobutyl acetate, butyl lactate, butyl levulinate; ketones such as ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone; ethylene glycol monobutyl ether, ethylene glycol benzyl ether, ethylene glycol monophenyl ether,
Benzyl alcohol, methylphenyl carbinol, n
- Alcohols such as amyl alcohol and methyl amyl alcohol; alkyl-substituted aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as methylene dichloride, ethylene dichloride, and monochlorobenzene. One or more of these organic solvents may be used. Among these organic solvents, ethylene glycol monophenyl ether and benzyl alcohol are particularly effective. Further, the content of these organic solvents in the developing solution is approximately 1 to 20% by weight, and particularly when the content is 2 to 10% by weight, a more preferable result fd is obtained.

On the other hand, the alkaline agents contained in the developer include (4) sodium silicate, potassium silicate, potassium hydroxide, sodium hydroxide, lithium hydroxide, sodium or ammonium salts of di- or tertiary phosphoric acid; , sodium metasilicate, sodium carbonate, ammonia and other inorganic alkali agents CB) mono-, di- or trimethylamine, mono-, di- or triethylamine, mono- or diisopropylamine,
Examples include organic amine compounds such as n-butylamine, mono-, di-, or triethanolamine, mono-, di-, or triisopropanolamine, ethyleneimine, and ethylenediamine.

The content of these alkaline agents in the developer is usually α0
5 to 4 layers, preferably (1L5 to 2 layers).

Further, in order to further improve storage stability, printing durability, etc., it is preferable to include a water-bathable sulfite in the developer. As such water bathable sulfites, alkali or alkaline earth metal salts of sulfites are preferable, such as sulfites.
+7um, potassium sulfite, lithium sulfite,
Examples include magnesium truesite. The content of these sulfites in the developer composition is usually α05~4ff19.
%, preferably 11 to 1% by weight.

Certain solubilizers may also be included to aid in the dissolution of the organic solvents mentioned above into the water. As such a solubilizing agent, in order to achieve the desired effects of the present invention, it is preferable to use low-molecular alcohols and ketones that are more water-soluble than the organic solvent used. Furthermore, anionic activators, amphoteric activators, etc. can also be used. Examples of such alcohols and ketones include methanol, ethanol,
It is preferable to use propatool, butanol, acetone, methyl ethyl ketone, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, methoxybutanol, ethoxybutanol, 4-methoxy-4-methylbutanol, and N-methylpyrrolidone cylinder. Preferred examples of the activator include sodium inglovir naphthalene sulfonate, sodium n-butylnaphthalene sulfonate, sodium N-methyl-N-pentadecylaminoacetate, and sodium lauryl sulfate. There is no particular restriction on the amount of solubilizers such as alcohols and ketones used, but it is generally preferable to use the amount of solubilizers, such as alcohols and ketones, at about 30 M% or less based on the entire developer.

After the photosensitive lithographic printing plate according to the present invention has been imagewise exposed, if it is brought into contact with the above-mentioned developer or rubbed, the photosensitive lithographic printing plate will be able to form a photosensitive composition after 10 to 60 seconds at a temperature of ~40°C. The photosensitive composition in the non-exposed areas is completely removed without adversely affecting the exposed areas of the layer.

Examples of fabrication of the support, diazo resin, and polymer used in the present invention are shown below.

(Support-1) An aluminum plate with a thickness of f124m is coated with 3% sodium f6 aqueous dispersion.
Immerse it in water, degrease it, wash it with water, use a dipping solution of 1% hydrochloric acid and 1% boric acid, and perform TFL decomposition etching at 15 A/dm for 1 minute, rinse it with water, and dilute it with 5% water. Desmut treatment was performed by immersion in a sodium hydroxide solution, followed by washing with water.

30% sulfuric acid aqueous solution at 50 A/am” at 30°C
Complete anodization for 0 seconds, rinse with water, and rinse with 1% metasilicic acid)
Immersed in IJum aqueous solution at 85°C for 37 seconds, and then heated at 90°C.
It was crushed in water at a temperature of 62° C. for 25 seconds, washed with water, and dried to obtain Support-1.

(Support-2) Anodized in a 40% phosphoric acid water bath at 60°C to 4.0 m
"Support-2 was obtained in the same manner as Support-1 except that the reaction was carried out for 30 seconds.

(Support-3) Aluminum sheet metal with thickness CL24, nylon brush and 400
Mesh pumice stone - water turbidity * After graining the surface, it was thoroughly washed with water, immersed in 10% sodium hydroxide water, and washed with water.

Below, all anodization and silicic acid treatment were carried out in the same manner as for support-1.
Support-3 Total Obtained t0 Next, the surface roughness of these supports was measured.

The surface roughness meter is from Perthen M.
, belt meter (perthometsr) S 5
The measurement was carried out using P k under the following measurement conditions.

Needle cartridge: RT-5DC (diamond needle, needle tip radius 5 μm) Needle sensitivity adjustment; Adjustment profile based on Pen-10-1, 9,0 μm; Roughness profile R Vertical Magnification; 2.5 μm Horizontal Magnification: 250 μm Measurement length: 4.0 Fin cutoff value: (18 scales Non-porosity (, tpmi), cut depth and center line average when the cut line depth C = RaX5 of the obtained support Table 1 shows the roughness RaQ values.

The values in Table 1 are the average values of 10 measurements.

Table 1 (Synthesis of Polymer 1) N-(4-human oxyphenyl) methacrylamide 11
02, acrylonitrile 25v1 ether acrylate)
60? , methacrylic acid 52 and azobisinbutyronitrile 1.642 fi acetone-methanol 1:1
Dissolved in mixed bath medium 112- and heated at 60°C under direct nitrogen exchange.
After heating for 0 hours, the reaction solution was poured into 5 t of water with stirring.
The resulting white precipitate was completely removed and dried to give Polymer 1 at 90? Obtained.

When the molecular weight of this polymer was determined by total gel permeation chromatography (hereinafter abbreviated as PC), the molecular weight was determined to be 3 (cage average molecular oil: a50,000).

(Synthesis of Polymer 2) A mixed solution of 2-hydroxyethyl methacrylate 452, acrylonitrile 10f1 ethyl methacrylate 45f, methacrylic acid 2f and 1.22 benzoyl peroxide,
The mixture was added dropwise over 2 hours to 300 tons of ethylene glycol monomethyl ether heated to 100°C. After the dropwise addition was completed, 300f of ethylene glycol monomethyl ether and benzoyl peroxide [L3f] were added, and the mixture was allowed to react for 4 hours.

After the reaction was completed, diluted with methanol, poured water 5 into it while stirring, collected the white precipitate, and dried it to give Polymer 2 to 93F.
Obtained.

Measure the molecular weight of this polymer using GPC.

As a result, the weight average molecule it was &50,000.

(Synthesis of Polymer 3) Methyl methacrylate 60f1 acrylonitrile 302,
Methacrylic acid 10? and azobisinftyronitrile 1
．． 5 f i was dissolved in methyl cellosolve 2002 and polymerized for 4 hours at 80° C. while passing nitrogen through. This reaction mixture was exposed to 5 tons of water, and the resulting white precipitate was collected and dried to obtain a polymer 5fL-70? Obtained.

When the molecular weight of this polymer t-GPc was measured,
Mf [average molecular weight was 60,000.

(Synthesis of Polymer 4) Polymer 4 was obtained by polymerizing 2-hydroxyethyl methacrylate 452, acrylonitrile 202, methyl methacrylate 309, and methacrylic acid 5f in the same manner as in the synthesis example of Polymer 3.

When the molecular weight of this polymer was measured by GPC, the weight average molecular weight t was &30,000.

(Synthesis of Diazo Resin-1) 14.5 P (50 mmol) of p-diazodiphenylamine sulfate was suspended in 4 cL99 m-sulfuric acid under ice cooling. <9 drops of 1.29 (40 mmol) of paraformaldehyde were added to the reaction solution. At this time, the reaction temperature was 10
The temperature was added so as not to exceed ℃. Thereafter, stirring was continued for 2 hours under water cooling.

This reaction mixture was added dropwise to 500 mL of ethanol under water cooling, and the resulting precipitate was filtered. After washing with ethanol, this precipitate was dissolved in 100-m pure water, and a cold concentrated water bath solution in which &81 zinc chloride was dissolved was added to this solution. The resulting precipitate was filtered, washed with ethanol, and dissolved in 150-pure water. To this liquid was added g of a cold concentrated aqueous solution in which 82 ammonium hexafluorophosphate was dissolved. The resulting precipitate was collected and washed with water, and then dried at 30°C for 1 day to obtain diazo m
Fat-1 was obtained.

The molecular weight of this diazo resin-1 was measured by GPC, and it was found that it contained about 55 moles of 5 or more caps.

(Synthesis of diazo resin-2) Synthesis was performed in the same manner as diazo resin-1, and instead of the final ammonium hexafluorophosphate, 2-hydroxy-4-
Diazo resin-2 was obtained by treatment with a water bath solution in which methoxy-benzophenone-5-sulfonic acid 152 was dissolved.

When this dian°-1 month-2 was analyzed by GPC', it was found that there were about 62 moles and 11 of more than 5 molecules.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to all examples,
The invention is not limited to these examples.

Examples 1 to 8, Comparative Example 1S4 Photosensitive liquids 1 to 4 having the compositions shown in Table 2 below were coated on the supports 1 to 3 obtained in the above production example using a wheeler. Thereafter, it was dried at a temperature of 85° C. for 3 minutes to obtain photosensitive lithographic printing plates of Examples 1 to 8 and Comparative Examples 1 to 4 shown in Table 3 below.

The resulting photosensitive lithographic printing plate was tested for processing ability and plate placement suitability using the following method.

(Processing capacity) Developing H-1 with the following composition and automatic developing machine PS for PS plates
Using P-860 (manufactured by Konishiroku Photo Industry Co., Ltd.), a photosensitive lithographic printing plate exposed to a 3 kW ultra-high pressure mercury lamp with an original with a picture area ratio of 10% was developed at 25° C. Development g1, which can be developed well in 20 seconds, was tested on the same area.

Developer-1 Benzyl alcohol
502 triethanolamine
15? Sodium sulfite
52 Butylnaphthalene sulfonic acid sodium 252 water
1000F (platform suitability) After printing 2000 sheets of printing plates made using developer-1 at Heidelberg Co., IQ C) To printer,
Complete cam pulling with gum solution 1, sex for 7 days, and then 2 again.
A test was conducted to determine how many times the mark 511 could be made without deteriorating the ink adhesion, assuming that 1,000 sheets were printed once.

Gum liquid-1 Enzyme-modified dextrin Goro 02
Gum Arabic 102 Lin FJ
2f water
1000? The above plate making test results and the results of each test are summarized in Table 3 below.

Table 3 [Effects of the Invention] As explained above, the photosensitive lithographic printing plate of the present invention can improve its suitability for plate placement without reducing sensitivity, developability, image reproducibility, and printability. This has a remarkable effect.

[Brief explanation of the drawing]

FIG. 1 is a graph explaining the non-void "4A".

Claims (1)

[Claims] 1. A photosensitive lithographic printing plate in which a photosensitive composition is coated on an aluminum support, the aluminum support comprising:
The photosensitive composition has a rough surface having a non-porosity ratio (TPMI) of 50% or more according to the abort load curve at a depth of 3 times the centerline average roughness (Ra), and the photosensitive composition is spread over the substrate for 14 m.
A photosensitive lithographic printing plate characterized by being coated with a coating of g/dm^2 or less. 2. The photosensitive lithographic printing plate according to claim 1, wherein the photosensitive composition is a photosensitive composition containing a diazo resin and a lipophilic polymer compound as main components.