JPH02229092A - Photosensitive lithographic printing plate - Google Patents

Abstract

PURPOSE:To improve an image reproducibility by a method wherein on the surface of an iron plate plated and further treated with a metal or metallic oxide sol as a substrate, a photosensitive layer containing a photopolymerizable compound or a photo-crosslinkable compound having at least one ethylene unsatd. group is provided. CONSTITUTION:The material of an iron plate used for a substrate includes an alloy of iron and other elements in addition to a pure iron. A sol is formed by using a metal or metallic oxide as a dispersion medium. As the metallic oxide, a hydrate may be used. As to the metal or metallic oxide as a dispersoid, all materials being positively charged in the sol can be used. A compound having at least one ethylene unsatd. double bond to be contained in a photosensitive layer is a component which is addition polymerized by action of a photodissociation product in a photopolymerization initiator (mixture) when a photopolymerizable composition forming the photosensitive layer is irradiated with an active light to change to a high polymer having a linear or network structure and a high molecular performance, enhance the curing of the photopolymerizable composition, and remarkably reduce or substantially eliminate the solubility of the composition in an organic and/or inorganic solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a negative photosensitive lithographic printing plate using a photopolymerizable compound or a photocrosslinkable compound as a photosensitive component.

[Background of the invention]

Conventionally, as a negative-working photosensitive lithographic printing plate used in the production of a lithographic printing plate, a photosensitive material having a photosensitive layer containing a photopolymerizable compound or a photocrosslinkable compound as a photosensitive component on a support made of an aluminum plate is known. ing.

However, such photosensitive planographic printing plates using conventional techniques have problems with the reproducibility of halftone dot images. Specifically, there are problems with so-called thick dots and poor shadow apertures. Compared to halftone negatives, the halftone dots on the printing plate obtained through exposure and development processing are increased in halftone dot area ratio,
There is a problem of impairing image reproducibility.

The present inventors have discovered that such problems can be improved by using iron material as the support, and have arrived at the present invention.

[Problem that the invention seeks to solve]

Therefore, an object of the present invention is to provide a negative photosensitive lithographic printing plate with improved image reproducibility (specifically, less dot thickening and good shadow opening).

[Failure to solve the problem]

The object of the present invention is to provide a photopolymerizable material having at least one ethylenically unsaturated group on the surface-treated surface of a support plated on the surface of an iron plate and further surface-treated with a metal or metal oxide sol. This is achieved by a photosensitive lithographic printing plate characterized by having a photosensitive layer containing a photocrosslinkable compound or a photocrosslinkable compound.

The present invention will be explained in detail below.

Materials for the iron plate used as the support for the photosensitive planographic printing plate of the present invention include pure iron as well as alloys of iron and other elements. Other elements that can be alloyed with iron include carbon, manganese, and nickel.Specifically, carbon steel (
Alloys of carbon (0.04-1.7%) and iron), cast iron, which has a higher carbon content than carbon steel, and other elements (e.g. manganese,
Special steels containing (nickel, chromium, cobalt, tungsten, molybdenum) (e.g. manganese steel, nickel steel,
chrome steel, nickel-chromium steel), etc.

The carbon steel mentioned above includes extremely mild steel (carbon 0.25% or less),
Soft 4N (0.2-0.5%), hard steel (carbon 0.5-1.
0%), extremely hard copper (carbon 1.0% or more).

A preferable iron plate is a cold rolled steel foil or a steel plate having a thickness of 30 to 250 μm. If the thickness of the steel plate exceeds 250 μM, it is difficult to process the plate and is also uneconomical in terms of material costs. Furthermore, if the thickness of the steel foil is less than 40 μm, the manufacturing cost is currently too high and it is uneconomical. Note that among cold-rolled steel foils, those with a thickness of 100 μm or less seem to be generally called steel foils, and there is no definite definition.

In the present invention, it is preferable that the surface of the iron plate on the side that will become the printing plate be roughened before being plated. The degree of roughening is
It is preferable that the average roughness Ra (JIS B 0601) of the surface after surface treatment with metal or metal oxide falls within the range described later.

Various conventionally known methods can be used to roughen the surface of the iron plate, including mechanical methods, chemical methods, and electrolytic methods.

Examples of the mechanical method include a pole polishing method, a brush polishing method, and a polishing method using liquid honing.

Chemical methods include etching with a solution containing sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, oxalic acid, pyro-IJ acid, ferric chloride, etc. The electrolytic method includes an electrolytic etching method and an electrolytic plating method. A preferable electrolytic plating method includes iron plating.

In the plating process in the present invention, Ni, Cr, Cu, Zn, or Sn, which has a rust-preventing effect on iron materials, is used as the plating metal. Note that the plating metal is not limited to the above-mentioned single metal, but also includes an alloy containing one or more of these metals, or a composite plating of two or more of these metals.

The thickness of the plating is not particularly limited, as long as it achieves the purpose of imparting corrosion resistance or adjusting the surface roughness, and the rest may be determined in consideration of economic efficiency.

After plating, chemical conversion treatment can be performed if necessary.

Chemical conversion treatment includes immersion in a solution containing chromate, dichromate, phosphate, molybdate, borate, perborate, etc., or electrolysis in the solution. It will be done.

Next, the surface treatment of the present invention, that is, the surface treatment using a metal or metal oxide sol will be explained.

The sol used in the present invention is a sol using a metal or metal oxide as a dispersion medium, and the metal oxide may be a hydrate, and the metal or metal oxide as a dispersoid is positively charged in the sol. That's fine.

The metal forming the dispersoid and the metal of the metal oxide are Aff
, Ti, Zr, Cr, Ni, Zn, Sn, Mn, Cu
, Co, Fe, Pb and Cd are preferred, more preferred are A(2, Cr, Zr, Ni and Zn, and particularly preferred are AQ, Zr and Ni).

In the sol used in the present invention, the metal and metal oxide are 2
More than one species can be mixed (this mixing may be done within the dispersoid particles or between the dispersoid particles) and used.

The particle size of the dispersoid made of metal or metal oxide is 1 to 500.
nm range is preferable; if it exceeds 500 nm, the adhesion of the sol to the plating layer will become non-uniform, and therefore the wood-philicity will become non-uniform, and if it is less than 1 nm, it will be difficult to produce the sol, it will be very expensive, and it will be economical. It lacks.

As the surface treatment method using a sol according to the present invention, it is preferable to perform cathodic electrolysis or immersion treatment in a treatment solution made of hydrosil containing metal and/or metal oxide as a dispersoid. The concentration of metals and metal oxides in the hydrosil is 1-
long/(t is preferably in the range.The concentration is Ig/
(If it is less than 2, there is no effect on hydrophilicity,]OOg/
Exceeding Q does not affect the hydrophilicity, but it is not preferable because it significantly impairs the appearance and at the same time unnecessarily consumes the sol due to drag-out.

The conditions for cathode electrolysis vary depending on the type of sol used, but suitable conditions are a current density of 0.5 to IOA/dm2, a treatment temperature of 5 to 50° C., and a treatment time of 1 to 60 seconds.

Dispersoids made of metals or metal oxides have a positive charge in hydrosil and are easily adsorbed to the metal layer, which is the plating layer, and the bond after adsorption is strong, so they are immersed in the processing solution. It is effective just by itself. In addition, it shows good hydrophilicity even if it is dried as it is after soaking, or even if it is washed with water and then dried, and the woodphilicity lasts for a long time. Furthermore, since the dispersoids are positively charged in the sol, if electrolysis is carried out using an iron plate as a cathode, the metal layer υ/or metal oxide, which is the dispersoid, will be electrophoretically adsorbed, and the metal layer υ/or the metal oxide will be mixed with the metal and/or metal oxide. The bond with the plating layer becomes even stronger.

Further, in order to stabilize the sol, an inorganic acid such as chromic acid, phosphoric acid, sulfuric acid, or hydrochloric acid, an organic acid such as citric acid or acetic acid, or a surfactant may be added to the treatment liquid. Since these acids are easily removed by washing with water, they do not cause a decrease in corrosion resistance.

Since the hydrophilic film on the plating layer obtained in this way is firmly bonded to the plating layer, it does not deteriorate over time. The treatment liquid consisting of a sol of metal or metal oxide is preferably neutral to weakly acidic and does not contain alkali ions.

Such surface treatment not only improves corrosion resistance but also effectively affects the adhesion of images formed on the printing plate. In particular, in the plating method, by appropriate growth of electrodeposited nuclei,
It is particularly effective because it also helps in secondary roughening of the surface. In that case, it is better to choose plating conditions that create uneven plating than smooth plating conditions, and it is economical to set the plating thickness so that the lower limit is a value that guarantees the corrosion resistance of the steel plate. It is not necessary to make the thickness of expensive metals such as Cr and Ni unnecessary, even if it is an inexpensive metal such as Zn.

In the support of the present invention, the surface-treated surface must have an average surface roughness Ra (JIS B
0601) is preferably in the range of 0.1-3 μm; if it is less than 0.1 pm, the surface will become nearly smooth and the hydrophilicity will not be sufficient, and if it exceeds 3 μm, it will be too rough, making it difficult to print images. There will be a lot of bleeding and good printed matter will not be obtained. Methods to obtain a surface roughness that is favorable for hydrophilicity include mechanical methods such as sanding, chemical methods such as etching the metal surface with a chemical solution, thick plating on the metal plate surface using electrolysis, or There are electrochemical methods for etching the surface, but the easiest method is to make adjustments during electroplating. Such surface roughness may be evaluated after performing the above-mentioned surface treatment.

The compound having at least one ethylenically unsaturated double bond (hereinafter referred to as an ethylenic compound) contained in the photosensitive layer of the present invention can be used when the photopolymerizable composition forming the photosensitive layer is irradiated with active light. Then, due to the action of the photodecomposition products of the photopolymerization initiator (mixture), it undergoes addition polymerization and changes into a highly polymerized substance with linear or network structure and high molecular weight, increasing the hardness of the photopolymerizable composition. , a component that significantly reduces its solubility in organic and/or inorganic solvents or renders it substantially insolubilizable.

An ethylenic compound is a compound having at least one ethylenically unsaturated double bond capable of addition polymerization in the chemical structure of one molecule, and is a monomeric prepolymer, that is, a dimer, trimer, or tetramer. and oligomers (meaning polymers or polycondensates with a molecular weight of about 10,000 or less), mixtures thereof, and copolymers thereof with a low degree of polymerization. Examples of ethylenic compounds include unsaturated carboxylic acids, unsaturated tunorboxates, unsaturated carboxylic acids and aliphatic polyhydroxy compounds (hereinafter referred to as aliphatic polyols), or aromatic polyhydroxy compounds (hereinafter referred to as polyhydric phenols). ), and oligoesters obtained by ester reaction from a polyhydric carboxylic acid having a valence of 2 or more, a polyhydroxylic compound having a valence of 2 or more and an unsaturated carboxylic acid.

The ethylenic compound is added to the photopolymerizable composition at room temperature (approximately 10°
When used as a substantially non-flowing composition (within the range of 100° C. to about 40° C.), those having a boiling point at atmospheric pressure of about 100° C. or higher can be used. However, when the photopolymerizable composition is used as a composition that is fluid at room temperature, the boiling point of the ethylenic compound under atmospheric pressure is about 30°C or higher, preferably about 40°C to about 100°C.
Temperature ranges up to

Specific examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, and maleic acid. Salts of unsaturated carboxylic acids include the aforementioned sodium salts and potassium salts of unsaturated carboxylic acids.

Examples of the aliphatic polyols mentioned above include ethylene glycol, triethylene glycol, tetraethylene glycol, tetramethylene glycol, neopentyl glycol, 1,10-decanediol, 1°2-butanediol, ■,3-butanediol, and propylene diol. , dihydric alcohols such as propylene glycol, trihydric alcohols such as trimethylolethane, trimethylolpropane, and their multimers, pentaerythritol, dipentaerythritol, tripentaerythritol, other multimers such as pentaerythritol, etc. Examples include alcohols with higher valences, sorbitol, d-mannitol, etc., and dihydroxycarboxylic acids such as dihydroxymaleic acid sugar.

Polyhydric phenols include hydroquinone, catechol,
These include resorcinol, 700 rogulunol pyrogallol, and the like.

Specific examples of esters of aliphatic polyols and unsaturated carboxylic acids include ethylene glycol diacrylate, triethylene glycol triacrylate, 1,3-butanediol diacrylate, and tetraacrylate. Methylene glycol ester, diacrylic acid propylene glycol ester, triacrylic acid trimethylolpropane ester, triacrylic acid trimethylol ethane ester,
diacrylic acid tetraethylene glycol ester, diacrylic acid pentaerythritol ester, triacrylic acid pentaerythritol ester, tetraacrylic acid pentaerythritol ester, diacrylic acid dipentaerythritol ester, triacrylic acid dipentaerythritol ester, tetraacrylic acid dipentaerythritol ester, Dipentaerythritol pentaacrylate ester, dipentaerythritol hexaacrylate ester, tripentaerythritol octaacrylate ester, dipentaerythritol tetraacrylate ester, dipentaerythritol pentaacrylate ester, dipentaerythritol hexaacrylate ester, Examples include tripentaerythritol octaacrylate ester, sorbitol triacrylate ester, sorbitol tetraacrylate ester, sorbitol pentaacrylate ester, sorbitol hexaacrylate ester, and polyester acrylate oligomer.

Examples of methacrylic acid esters include tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, pentaerythritol dimethacrylate, and pentaerythritol trimethacrylate. Little ester, dipentaerythritol dimethacrylate ester, pentaerythritol trimethacrylate ester, dipentaerythritol dimethacrylate ester, dipentaerythritol tetramethacrylate ester, tripentaerythritol octamethacrylate ester, ethylene glycol dimethacrylate ester, dimethacrylate Examples include acid-1,3-butanediol ester, dimethacrylic acid tetramethylene glycol ester, and tetramethacrylic acid sorbitol ester.

Examples of itaconic acid esters include ethylene glycol diitaconate, propylene gellicol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, and diitaconate. Examples include pentaerythritol ester, dipentaerythritol triitaconate ester, dipentaerythritol pentitaconate ester, dipentaerythritol hexitaconate ester, and sorbitol tetraitaconate ester.

Examples of crotonic acid esters include dicrotonic acid ethylene glycol ester, dicrotonic acid propylene glycol ester, dicrotonic acid tetramethylene glycol ester, dicrotonic acid pentaerythritol ester, and tetracrotonic acid sorbitol ester.

Examples of incrotonic acid esters include diisocrotonic acid ethylene glycol ester, diisocrotonic acid pentaerythritol ester, and tetraisocrotonic acid sorbitol ester.

Examples of maleic esters include ethylene glycol cymaleate, triethylene glycol cymaleate, pentaerythritol cymaleate, and sorbitol tetramaleate.

Mention may also be made of mixtures of the aforementioned esters.

Examples of the above-mentioned oligoesters include oligoester acrylates and oligoester methacrylates (hereinafter, either or both of them will be simply referred to as oligoester (meth)acrylates).

Oligoester (meth)acrylate is a reaction product obtained by the esterification reaction of acrylic acid or methacrylic acid, a polyhydric carboxylic acid, and a polyol, and the estimated structural formula is a compound represented by the general formula CI). , general formula CI) heat (co2-c-c-ant "Q" where R represents a hydrogen atom or a methyl group, and Q is poly=16
= At least 1 consisting of a hydric alcohol and a polyhydric carboxylic acid
represents an ester residue containing two ester bonds, p is 1 to
It is an integer of 6.

Examples of the polyol constituting the ester residue Q include ethylene glycol, 1,2-propylene glycol,
■, 4-butanediol, 1,6-hexanediol, trimethylolpropane, trimethylolethane, 1,2
．． Polyols such as 6-hexanediol, glycerin, pentaerythritol, sorbitol, diethylene glycol, triethylene glycol, tetraethylene glycol, decaethylene glycol, tetradecaethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, polypropylene glycol There are polyether type polyols such as

On the other hand, examples of the polycarboxylic acids constituting the ester residue Q include phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, tetrabromophthalic acid, trimellitic acid, pyromellitic acid, benzophenonedicarboxylic acid, and resorcinol dicarboxylic acid. Aromatic polycarboxylic acids such as acetic acid and bisphenol A diacetic acid; unsaturated aliphatic polycarboxylic acids such as maleic acid, fumaric acid, hemic acid, and itaconic acid;
Examples include saturated aliphatic polycarboxylic acids such as malonic acid, succinic acid, geltaric acid, adipic acid, pimelic acid, sebacic acid, dodecanoic acid, and tetrahydrophthalic acid.

The ester residue Q is composed of one type each of the above polyol and polycarboxylic acid,
and one or both of which are composed of two or more kinds.

Also included are those in which one molecule each of polyol and polycarboxylic acid is contained in the ester residue Q, and those in which two or more molecules of one or both of them are contained. That is, any material can be used as long as Q contains at least one ester bond. Also included are those in which a hydroxyl group remains in Q, or those in which this forms an ester with a -valent carboxylic acid, or those substituted with an alkoxy group such as a methoxy group or an ethoxy group. Further, carboxylic acid may remain in Q. The number of p in the general formula [■] and the number of ester bonds contained in Q are usually in the range of 1 to 6. When the value of p is 2 or more, one polyester (meth)acrylate molecule containing either an acryloyl group or a methacryloyl group may be used; and a methacryloyl group in any proportion.

Table 1 lists the estimated structural formulas of specific examples of oligoester (meth)acrylates. Other examples of oligoesters include unsaturated esters described in JP-A-47-9676 (corresponding to US Pat. No. 3,732,107). In Table 1, 2 in the structural formula is an acryloyl group (CH2-CH-C-) or a methacryloyl group Table 1 Oligoester (meth)acrylate Z 0
CH2CH200CCHCHC00CLCLOHH3C
H3 Z-OCH2CH-00C-CH2Cl(2-Coo-
CH2H20H2-0 (CH2CH20)TQC-c6
H, -Co(OCI(2CH2)20HzIO(:CH
ga, ooc (CH row πO piece 0 (CH2CH2-CH3Z
-OCH2CH200C-CIlH, -COOCH2C
H20-ZZi0CH2CH200C-C6H, -Co
)-zOcH2CH20-Z7.0 (CH2CH2O
)JCCHCOCo (OCI(20H→3O-ZZ thousand(OCH2CH2+300C-(CB2 4 C0tz
O(CH2CH20h ZZ-E(OCFI□CH, r
)-,0OC-C6H,-CO]i0iCH2CH2O
Soup Zz-(OCH2CII2u+oOOCCH2coo
-(cn2cu2o),,zCO-(OCH2CH2C
H2C H20CH2CH200C(CH2)tCOO(Ck OH) The photopolymerizable composition containing the photopolymerizable compound of the present invention contains the above-mentioned compound having an ethylenically unsaturated bond and a photopolymerization initiator as essential components. In practice, a binder and other auxiliary additives such as a thermal polymerization inhibitor, a coloring agent, and a plasticizer are usually used in combination.

Specific examples of thermal polymerization inhibitors include p-methoxyphenol, hydroquinone, alkyl- or aryl-substituted hydroquinone, t-butylcatechol, pyrogallol,
Phenothiazine, chloranil, naphdylamine, β-naphthol, 2,6-di(-butyl-p-cresol, pyridine, nitrobenzene, p-dinitrobenzene, p-
Examples include toluidine.

These thermal polymerization inhibitors can be contained in a weight ratio of about 0001% to about 5%, preferably about 0.01% to about 3%, based on the above-mentioned ethylenic compound. . The thermal polymerization inhibitor has the function of improving the stability over time of the photopolymerizable composition of the present invention before use (before exposure).

Examples of coloring agents include pigments such as titanium oxide, carbon black, iron oxide, phthalocyanine pigments, and azo pigments, and dyes such as methylene blue, crystal violet, rhodamine B1 fuchsin, auramine, azo dyes, and anthraquinone dyes. Preferably, the colorant used does not absorb light at the absorption wavelength of the photopolymerization initiator.

Such a coloring agent is preferably 0.1 to 30 parts by weight in the case of a pigment and 0.01 to 10 parts by weight in the case of a dye, based on 100 parts by weight of the total amount of the ethylenic compound and the binder. It is preferable to contain it in a range of 0.1 parts by weight to 3 parts by weight.

When containing the above coloring agent, it is preferable to use dichloromethyl stearate and other chlorinated fatty acids as auxiliary substances for the coloring agent, and the amount thereof is 0.005 parts by weight per 1 part by weight of the coloring agent. % to 0.5 part by weight. However, if a plasticizer is included in the photopolymerizable composition, no colorant auxiliary substance is required.

Examples of the photocrosslinkable compound used in the present invention include those shown below. That is, examples thereof include polyesters, polycarbonates, polyamides, polyacrylic acid esters, polyvinyl alcohol derivatives, epoxy resin derivatives, etc. containing polyesters in the main chain or side chain of the polymer. In the above formula, R1 and R2 are alkyl groups having 1 to 10 carbon atoms, and R3 and R4 are hydrogen, halogen atoms, and 1 to 10 carbon atoms.
represents an alkyl group or a cyan group. The molecular weight is not limited as long as it is soluble in the solvent, but the molecular weight is 1000~
It is advantageous to choose from a range of tens of thousands. Particularly preferred polymers include, for example, U.S. Patent No. 3.03Q
, No. 208 and No. 3,707,373, such as a photosensitive polymer containing a photosensitive group in the polymer main chain, for example, a photosensitive polymer consisting of p-phenyl diacrylic acid and a diol. Ester, U.S. Patent 2°956
, 878 and 3, 173, 787, such as those derived from 2-properidenmalone oxide such as cinnamylidenemalonic acid and difunctional glycols. photosensitive polyester, U.S. Pat. No. 2,690,966, U.S. Pat. No. 2,752.
372 and 2,732.301, such as cinnamate esters of hydroxyl-containing polymers such as polyvinyl alcohol, starch, cellulose and the like. Examples include those that become insolubilized by the action of light.

Examples of the photosensitizer to be contained in the photosensitive resin layer in the present invention include the following.

For example, US Pat. No. 2,610.120, US Pat. No. 2,670.
No. 285, No. 2,670,286, No. 2,670.2
No. 87, No. 2,690,966, No. 2,732,30
No. 1, No. 2,835.656, No. 2,956,878
No. 3,023,100, No. 3,066.117, No. 3,141.770, No. 3,173,787,
No. 3,357,831, No. 3,409,593, No. 3,418,295, No. 3,453.110, No. 3
, No. 475,617, No. 3,561.969, No. 3,
No. 575.929, No. 3,582,327, No. 3,6
47.470, 3,721.566, 3,73
7. Those described in No. 319, etc. Specific examples of particularly useful sensitizers include 2-benzoylmethylene-1-methyl β-naphthothiazoline, 5-nitroacenaphthene, β-chloroanthraquinone, l,2-benzalanthraquinone, p, p '-tetraethyldiaminodiphenylketone, p,p'-dimethylaminobenzophenone,
Includes 4-nitro-2-chloroaniline and the like.

The ratio of the sensitizer used is preferably in the range of 0.5 to 15% by weight (hereinafter abbreviated as %) based on the weight of the polymer, and a particularly preferred range is 2 to 8%.

The photopolymerizable composition as described above can be supported by being dissolved in a suitable solvent such as 2-methoxyethanol, 2-methoxyethyl acetate, cyclohexane, methyl ethyl ketone, or ethylene dichloride alone or in a mixed solvent of an appropriate combination thereof. The coating amount is suitably in the range of about 0.1 to about 10 g/m 2 , more preferably 0.5 to 5 g/m 2 in weight after drying.

On the layer of the photopolymerizable composition provided on the support, in order to prevent polymerization inhibition caused by the influence of oxygen in the air,
For example, it is preferable to provide a protective layer made of a polymer with excellent oxygen barrier properties, such as polyvinyl alcohol or acidic cellulose.

A method for applying such a protective layer is described in detail in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729.

In order to create a lithographic printing plate using the photosensitive lithographic printing plate of the present invention, the photosensitive lithographic printing plate is first imagewise exposed using a light beam rich in ultraviolet rays such as a metal halide lamp or a high-pressure mercury lamp, and then developed. The unexposed areas of the photosensitive layer are removed by treatment with a liquid, and finally a gum liquid is applied to form a lithographic printing plate.

Preferably, the developer is an alkaline aqueous solution containing a small amount of an organic solvent such as benzyl alcohol, 2-phenoxyethanol, or 2-butoxyethanol, such as those described in U.S. Pat. No. 3,475,171 and No. 3,615.
Examples include those described in No. 480.

Furthermore, Japanese Patent Publication No. 50-26601, Japanese Patent Publication No. 56-394
64 and No. 56-42860 are also excellent as developers for the photosensitive printing plate of the present invention.

〔Example〕

EXAMPLES The present invention will be specifically explained below using Examples, but the present invention is not limited to these Examples unless the gist of the invention is exceeded.

Preparation of support Support-1 A flat surface of a steel plate with a thickness of 015 mm was roughened by etching with a Baume 40' ferric chloride solution, and then heated in a sulfate bath at a temperature of 50'O and a current density of 5A/ Under the conditions of dm2,
After plating Zn to 4 μm, the particle size was 110 as parent wood treatment.
0n Cr sol 20g10. With a solution containing 10 g IQ of phosphoric acid, electrolysis was carried out for 30 seconds at a current density of 2 A/dm'' using a steel plate as a cathode, washed with water and dried to obtain Support-1.

Support-2 The surface of a rolled steel foil with a thickness of 0.09 mm was plated with 5 μm of Fe to give a surface roughness (Ra) of 0.4 μm, and further heated using a Sargent bath at a temperature of 45° C. and a current density of 40 A.
Cr plating with a thickness of 0.1 μl was performed under the conditions of “/dm”, and as a hydrophilic treatment, it was immersed in an aqueous solution containing 30 g/Q of alumina sol (Alumina Sol-200, manufactured by Temade Kagaku) with a particle size of 50 nm and 5 g of chromic acid #2. and dry it to form a support.
I got 2.

Support-3 A 0.24 mm thick aluminum plate (material 1050, tempered H16) was heated to 60 mm in a 5% by weight aqueous sodium hydroxide solution.
°C″c′ After degreasing for 1 minute, if 0.5
In molar hydrochloric acid aqueous solution, temperature: 25°C, current density: 6
Electrolytic etching treatment was performed under the conditions of 0 A/dm2 and treatment time: 30 seconds. Then, after desmutting in a 5% by weight aqueous sodium hydroxide solution at 60°C for 10 seconds, the desmut treatment was performed in a 20% by weight sulfuric acid solution at a temperature of 20°C, current density: 3A/dm2, and treatment time: 1 minute. Anodizing treatment was performed on the aluminum plate, followed by hot water sealing treatment for 20 seconds with hot water at 30° C. to produce an aluminum plate as a support for a lithographic printing plate material.

Preparation of photosensitive layer coating liquid (photosensitive liquid) Photosensitive liquid-1 Condensate of xylene diamine and glycidyl methacrylate (1:4 molar ratio) 1.75
g Poly(copolymer of 2-hydroxyethyl methacrylate and methyl methacrylate (80:20 molar ratio) and 1:l (molar ratio of polymer hydroxyl group to incyanate) condensate of 2-incyanate ethyl methacrylate) 3.25g light Acid generator (below) 0.2g Victoria Buy Your Blue BOH (manufactured by Sakudogaya Chemical Co., Ltd.) 0.16
gMichler Ketone 0.2g
Methyl ethyl ketone 40g2-
Methoxyethanol 40g2.2
1:1 condensation product of '-dimethylolpropanoic acid and hexamethylene incyanate 5g Photosensitive solution-2 Photosensitization by condensation of p-phenylene diacrylic acid ester and 1,4-dihydroxyethyloxycyclohexane in a 1:1 (molar ratio) gender unsaturated polyester
2g 1-Methyl-2-benzoylmethine β-naphthothiazoline 0.1g2.
1.J (molar ratio) polycondensation polyurethane of 2'-dimethylolpropanoic acid and hexamethylene diisocyanate 3.5g
Photogenerating agent (below) 0.2g Victoria Buy Your Blue BOH (manufactured by Sakudogaya Chemical Co., Ltd.) 0.12
g2-Methoxyethanol 20g Methyl ethyl ketone 20g Photosensitive lithographic printing plate samples No. 1 to No. 5 were prepared using the combinations of the support and photosensitive solution shown in Table 2 below. A 2KW metal halide lamp (Iwasaki Electric Co., Ltd.
After exposure using Idol Fin 2000) as a light source, standard development (
The reproducibility of small dots and the opening of a part of the shadow were measured for the sample obtained by diluting the sample at a dilution rate of 6 times, 25° 0.40 seconds).

The results are shown in Table 2.

Table 2 Generating agent [Effect of the invention] According to the present invention, a negative photosensitive lithographic printing plate with improved image reproducibility (specifically, less dot thickening and good shadow opening) is produced. Obtainable.

(Note) Halftone dot area ratio on the plate corresponding to 5% halftone dot of halftone positive, measured with Sakura Area Duck.

Claims (1)

[Claims] A photopolymerizable compound or a photocrosslinkable compound having at least one ethylenically unsaturated group on the surface-treated surface of a support plated on the surface of an iron plate and further surface-treated with a sol of a metal or metal oxide. A photosensitive lithographic printing plate characterized by having a photosensitive layer having: