JP2003107742A - Method for making up printing plate and developer to be used therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for making up a printing plate having excellent contrast between an image area and a nonimage area, sufficiently maintaining a residual film ratio in the image area and consequently securing a broad range of choice for a development condition, also at the same time preventing development performance from degraded due to developer fatigue after a prolonged period of use and being extremely advantageous to industrial applications and to provide the developer used therein. SOLUTION: The developer has a pH of 12 or higher and contains >10,000 ppm surfactant, an alkali metal hydroxide and an alkali metal silicate. In the method for making up the printing plate, an original plate for a planographic printing plate having a photosensitive layer containing a photothermal conversion material and an alkali soluble resin having a phenolic hydroxyl group is developed with the developer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a plate making method for a printing plate from a lithographic printing plate precursor having a photosensitive layer containing a photothermal conversion substance and an alkali-soluble resin having a phenolic hydroxyl group, and a developer used therefor, in particular. The present invention relates to a method for making a printing plate from a lithographic printing plate precursor having a positive photosensitive layer suitable for direct plate making by a semiconductor laser or a YAG laser, and a developer used therefor.

[0002]

2. Description of the Related Art With the progress of computer image processing technology, a photo-sensitive or heat-sensitive direct plate-making method for directly forming a resist image by a laser beam or a thermal head without outputting from digital image information to a silver salt mask film. The system is receiving attention. In particular, a high-resolution laser-sensitive direct plate-making system using a high-output semiconductor laser, a YAG laser, or the like is strongly desired to be realized in terms of downsizing, ambient light during plate-making work, plate material cost, and the like. It was

On the other hand, conventionally, as an image forming method utilizing laser exposure or heat sensitivity, a method of forming a color material image using a sublimation transfer dye, a method of producing a lithographic printing plate, and the like are known. Specifically, for example, a method of producing a lithographic printing plate using a crosslinking reaction of a diazo compound (for example, JP-A-50-15603, JP-A-52-151024, JP-B-60-12939, Japanese Patent Publication No. 61-21831, Japanese Patent Publication No. 2-51732, Japanese Patent Publication No. 3-34051, U.S. Pat. No. 366473.
See the specification such as No. 7. ), And a method for producing a lithographic printing plate by utilizing a decomposition reaction of nitrocellulose (see, for example, JP-A-50)
-102401, each Unexamined-Japanese-Patent No. 50-102403, etc. reference. ) Etc. are known.

In recent years, a technique in which a chemically amplified photoresist is combined with a long-wavelength light absorbing dye has come into widespread use. For example, JP-A-6-43633 discloses a photosensitive material in which a photo-acid generator and a binder are combined with a specific squarylium dye, and as a technique similar thereto, JP-A-7-20629. JP-A-7-271029 discloses a method for producing a lithographic printing plate by imagewise exposing a photosensitive composition layer containing an infrared absorbing dye, a latent Bronsted acid, a resole resin and a novolac resin to an image with a semiconductor laser or the like. JP-A-9-43847 discloses a method of using an s-triazine compound in place of the latent Bronsted acid.
A resist material that changes the crystallinity of a photosensitive material by being heated by irradiation of infrared rays and a pattern forming method using the resist material,
Further, JP-A-10-3165 discloses a photosensitive composition in which a specific dissolution inhibitor and an infrared absorbing dye are combined with an acrylic resin or the like as a binder.

However, these conventional techniques are not suitable for negative-type photosensitive compositions that require heat treatment after exposure.
The image obtained by the processing conditions is not always stable, and in a positive-type photosensitive composition that does not require heat treatment after exposure, the contrast between the image area and the non-image area is insufficient, and as a result However, the non-image area is not sufficiently removed, the residual film rate of the image area is not sufficiently maintained, and therefore, the range of developing conditions is narrow, which is a practical defect.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art, and is excellent in the contrast between the image portion and the non-image portion, and the residual film rate of the image portion is sufficiently maintained. Therefore, it is an object of the present invention to provide a method for making a printing plate from a lithographic printing plate precursor having a positive photosensitive layer having a wide range of development conditions, and a developer used therefor. At the same time, it is another object of the present invention to provide an industrially extremely advantageous plate-making method for a printing plate and a developer used therefor, which can prevent the developing solution from being fatigued and the developing performance from being deteriorated during long-term use.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, for lithographic printing plates having a photosensitive layer mainly containing a photothermal conversion substance and an alkali-soluble resin having a phenolic hydroxyl group. The present invention has been completed by finding that the above object can be achieved by developing the original plate with a specific developing solution. That is, the present invention is
A lithographic printing plate precursor having a photosensitive layer containing a photothermal conversion substance and an alkali-soluble resin having a phenolic hydroxyl group, after laser exposure, contains an alkali metal hydroxide and an alkali metal silicate and has a pH of 12 or more. And, and
The gist is a plate making method of a printing plate which is developed with an alkaline developer containing an amount of surfactant exceeding 10,000 ppm, and a developing solution used therefor. Further, the amount of the surfactant exceeds 10,000 ppm during its running. It is also characterized in that a replenisher is added to.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The printing plate making method and developing solution of the present invention will be described in detail below. Among them, the developing solution, which is the most important requirement, will be described first.

The developer of the present invention has a pH of 12 or more and 10
It contains a surfactant, an alkali metal hydroxide and an alkali metal silicate in an amount exceeding 000 ppm. In the developer of the present invention, the content of the surfactant is
It is essential to exceed 10000 ppm, but in particular,
The content is preferably 10100 ppm or more and 15000 ppm or less. When the surfactant is not contained, or even when the surfactant is contained, it is 10,000 ppm or less, so that the range of development conditions becomes narrow and the object of the present invention cannot be achieved.

The type of the surfactant is not particularly limited, and any of cationic, anionic, nonionic or amphoteric surfactants can be used. Here, as the cationic surfactant, specifically, for example, lauryltrimethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, distearyldimethylammonium chloride, perfluorotrimethylammonium chloride, Quaternary ammonium salts such as laurylpyridinium chloride, imidazoline derivatives such as 2-octadecyl-hydroxyethyl-2-imidazoline, N, N-diethyl-stearoamide-methylamine hydrochloride, amine salts such as polyoxyethylenestearylamine, etc. Can be mentioned.

As the anionic surfactant, higher fatty acid salts such as sodium laurate, sodium stearate and sodium oleate, alkyl sulphate salts such as sodium lauryl sulphate and sodium stearyl sulphate, sodium octyl alcohol sulphate,
Higher alcohol sulfate ester salts such as sodium lauryl alcohol sulfate ester and ammonium lauryl alcohol sulfate ester, Aliphatic alcohol sulfate ester salts such as sodium acetyl alcohol sulfate ester, Alkylbenzenesulfonate salts such as sodium dodecylbenzenesulfonate, Sodium isopropylnaphthalenesulfonate Alkylnaphthalene sulfonates such as
Alkyl diphenyl ether disulfonates such as sodium alkyl diphenyl ether disulfonate, sodium lauryl phosphate, alkyl phosphate ester salts such as sodium stearyl phosphate, polyethylene oxide adduct of sodium lauryl ether sulfate, polyethylene oxide adduct of ammonium lauryl ether sulfate,
Lauryl ether Polyethylene oxide adduct of alkyl ether sulfate such as polyethylene oxide adduct of triethanolamine sulfate, polyethylene oxide adduct of alkyl phenyl ether sulfate such as polyethylene oxide adduct of sodium nonylphenyl ether sulfate, lauryl ether Examples thereof include polyethylene ether adducts of alkyl ether phosphates such as sodium phosphate adducts of sodium phosphate, and polyethylene oxide adducts of alkyl phenyl ether phosphates such as polyethylene oxide adduct of sodium nonylphenyl ether phosphate.

As the nonionic surfactant, polyethylene glycols such as polyethylene glycol and polyethylene glycol polypropylene glycol block copolymers, polyethylene glycol such as polyethylene glycol cetyl ether, polyethylene glycol stearyl ether, polyethylene glycol oleyl ether and polyethylene glycol behenyl ether are used. Polyethylene glycol polypropylene glycol alkyl ethers such as glycol alkyl ethers, polyethylene glycol polypropylene glycol cetyl ether, polyethylene glycol polypropylene glycol decyl tetradecyl ether, polyethylene glycol octyl phenyl ether, polyethylene glycol nonyl phenyl ether, etc. Polyethylene glycol alkyl phenyl ethers, ethylene glycol monostearate, ethylene glycol distearate, diethylene glycol stearate, polyethylene glycol distearate, polyethylene glycol monolaurate,
Polyethylene glycol fatty acid esters such as polyethylene glycol monostearate and polyethylene glycol monooleate, glyceryl monomyristate, glyceryl monostearate, glyceryl monoisostearate, glyceryl distearate, glyceryl monooleate, glyceryl fatty acid such as glyceryl dioleate Esters, and polyethylene oxide adducts thereof, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, and other sorbitan fatty acid esters, and polyethylene oxide adducts thereof, Monolauric acid sorbite, tetrastearic acid sorbite, hexastearic acid sorbite, tetraoleic acid solbit Sorbit fatty acid esters such as Tsu bets, and polyethylene oxide adducts, can be mentioned castor oil polyethylene oxide adducts such as.

As the amphoteric surfactant, N-lauryl-N, N-dimethyl-N-carboxymethylammonium, N-stearyl-N, N-dimethyl-N-carboxymethylammonium, N-lauryl-N, N-dihydroxyethyl-N-carboxymethyl ammonium,
Betaine-type compounds such as N-lauryl-N, N, N-tris (carboxymethyl) ammonium, imidazolium salts such as 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolium, imidazoline-N
-Sodium ethyl sulfonate, imidazoline-N-
Examples thereof include imidazolines such as sodium ethyl sulfate.

Among the above surfactants, in the present invention, the quaternary ammonium salts as cationic surfactants, the various polyethylene glycol derivatives as nonionic surfactants, and the various polyethylenes as described above. Polyethylene oxide derivatives such as oxide adducts and betaine type compounds as amphoteric surfactants are preferable.

The developer of the present invention must have a pH of 12 or more, but it is preferably 12.5-14.0. When the pH is less than the above range, the releasability of the exposed area becomes poor. The developer of the present invention, as an alkaline agent,
It contains an alkali metal hydroxide and an alkali metal silicate. Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like. Examples of alkali metal silicates include sodium silicate, potassium silicate, and lithium silicate.

As the content of alkali metal silicate,
Although not particularly limited, the content as silicon dioxide is 0.
5 to 5 mass% is preferable, and more preferably 1.0 to 4.
It is 0 mass%. If the content as silicon dioxide is less than the above range, the hydrophilicity becomes insufficient, and if it exceeds the above range, insoluble matter is likely to appear in the developing solution, and in any case, the range of developing conditions may be narrowed.

In addition to the alkali agent and the surfactant, the developer of the present invention may further contain additives such as a water softener, a pH adjuster and a defoaming agent, if necessary. be able to. These additives are preferably contained in the developing solution in an amount of 0.001 to 5% by mass, particularly preferably 0.005 to 5% by mass.
It can be contained at a concentration of 3% by mass. The development is usually carried out by immersion development, spray development, brush development, ultrasonic development or the like at a temperature of preferably about 10 to 50 ° C, particularly preferably about 20 to 40 ° C.

Next, the planographic printing plate precursor used in the plate making method of the present invention will be described. The lithographic printing plate precursor used in the plate making method of the present invention has a photosensitive layer containing a photothermal conversion substance and an alkali-soluble resin having a phenolic hydroxyl group. The photosensitive layer is composed of a positive photosensitive composition containing a photothermal conversion substance and an alkali-soluble resin having a phenolic hydroxyl group.

The photothermal conversion substance contained in the positive photosensitive composition is a substance which absorbs light mainly in the near infrared region of the image exposure light source and converts it into heat. Here, the photothermal conversion substance is not particularly limited as long as it is a compound that can convert absorbed light into heat, but the wavelength range is 650 to 1300 nm.
A light absorbing dye having an absorption band in part or all of is particularly effective. While these light-absorbing dyes efficiently absorb light in the wavelength range, they hardly absorb light in the ultraviolet region, or they are substantially insensitive to absorption, and are weakly affected by the weak ultraviolet light contained in white lamps. Is a compound which does not act to modify the photosensitive composition.

These light absorbing dyes include nitrogen atoms,
Typical examples include so-called cyanine dyes in a broad sense, in which a heterocycle containing an oxygen atom, a sulfur atom, or the like is bonded with polymethine (-CH =) n, and specifically, for example, quinoline ( So-called narrowly defined cyanine), indole-based (so-called indocyanine-based), benzothiazole-based (so-called thiocyanine-based), iminocyclohexadiene-based (so-called polymethine-based), pyrylium-based, thiapyrylium-based, squarylium-based, croconium-based , Azurenium-based, and the like. Among them, quinoline-based, indole-based, benzothiazole-based, iminocyclohexadiene-based, pyrylium-based, and thiapyrylium-based are preferable.
In addition, phthalocyanine dyes are also representative.

In the present invention, among the above-mentioned cyanine dyes, the quinoline dyes are particularly represented by the following general formula (I
Those represented by a), (Ib), or (Ic) are preferable.

[0022]

[Chemical 1]

[In the formulas (Ia), (Ib), and (Ic), R ¹ and R ²
Each independently represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, or a substituent which may have a substituent. Represents a phenyl group, L ¹ represents a tri, penta, or heptamethine group which may have a substituent, and the two substituents on the penta or heptamethine group are linked to each other and have 5 to 7 carbon atoms. May form a cycloalkene ring, and the quinoline ring may have a substituent. In that case, two adjacent substituents may be linked to each other to form a condensed benzene ring. X ⁻ represents a counter anion. ]

Here, R ¹ in the formulas (Ia), (Ib), and (Ic)
Examples of the substituent for R ² and R ² include an alkoxy group, a phenoxy group, a hydroxy group, and a phenyl group. Examples of the substituent for L ¹ include an alkyl group, an amino group, and a halogen atom, and a quinoline ring. Examples of the substituent in are an alkyl group, an alkoxy group, a nitro group, a halogen atom and the like.

As the indole and benzothiazole dyes, those represented by the following general formula (II) are particularly preferable.

[0026]

[Chemical 2]

[In the formula (II), Y ¹ and Y ² are each independently
A dialkylmethylene group or a sulfur atom, R ³ and R ⁴
Each independently represents an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, or a substituent which may have a substituent. A phenyl group, L ² represents a tri-, penta-, or heptamethine group which may have a substituent, and the two substituents on the penta- or heptamethine group are linked to each other and have 5 to 7 carbon atoms. May form a cycloalkene ring, and the condensed benzene ring may have a substituent. In that case, two adjacent substituents may be bonded to each other to form a condensed benzene ring. . X ⁻ represents a counter anion. ]

Here, examples of the substituent in R ³ and R ⁴ in the formula (II) include an alkoxy group, a phenoxy group, a hydroxy group, a phenyl group, and the like, and a substituent in L ² is an alkyl group. , An amino group, a halogen atom and the like, and examples of the substituent on the benzene ring include an alkyl group, an alkoxy group, a nitro group and a halogen atom.

Further, as the iminocyclohexadiene dye, those represented by the following general formula (III) are particularly preferable.

[0030]

[Chemical 3]

[In the formula (III), R^Five, R⁶, R⁷, And R⁸Is
Each independently represents an alkyl group, R ⁹And R^TenAre each
Independently, an aryl group which may have a substituent and a free group
L group or thienyl group, L³Has a substituent
A mono-, tri-, or pentamethine group which may
Two substituents on a poly or pentamethine group are linked to each other
May form a cycloalkene ring having 5 to 7 carbon atoms
Yes. X^-Represents a counter anion. ]

Specific examples of R ⁹ and R ¹⁰ in the formula (III) are phenyl group, 1-naphthyl group, 2-naphthyl group, 2-furyl group, 3-furyl group and 2-thienyl group. ,
3-thienyl group etc. are mentioned, and those substituents include an alkyl group, an alkoxy group, a dialkylamino group,
Examples thereof include a hydroxy group and a halogen atom, and examples of the substituent for L ³ include an alkyl group, an amino group, and a halogen atom.

As the pyrylium-based and thiapyrylium-based dyes, particularly, the following general formulas (IVa), (IVb), or
Those represented by (IVc) are preferred.

[0034]

[Chemical 4]

[In the formulas (IVa), (IVa), and (IVc), Y³
And Y^FourEach independently represents an oxygen atom or a sulfur atom.
And R¹¹, R¹², R¹³, And R¹⁴Are each independently hydrogen
Atom or alkyl group, or R¹¹And R¹³, And R¹²And R
¹⁴Are linked together to form a cycloalkene ring having 5 or 6 carbon atoms
L may be formed,^FourMay have a substituent
A mono-, tri-, or pentamethine group,
Two substituents on the pentamethine group are linked together to form a carbon
It may form a cycloalkene ring of several 5 to 7,
Lylium ring and thiapyrylium ring have substituents
In that case, two adjacent substituents are linked to each other.
And may form a condensed benzene ring. X ^-Is a
Indicates Nion. ]

Here, the substituent in L ⁴ of the formulas (IVa), (IVa) and (IVc) is an alkyl group, an amino group,
Alternatively, a halogen atom or the like can be used, and examples of the substituent on the pyrylium ring and thiapyrylium ring include an aryl group such as a phenyl group and a naphthyl group.

The above general formulas (Ia to c), (II), (III),
And the counter anion X in (IVa to c) ^-As an example
For example, Cl^-, Br^-, I^-, ClO_Four ^-, PF₆ ^-, And B
F_Four ^-, BCl_Four ^-Inorganic boric acid and other inorganic acid anions, Ben
Zensulfonic acid, p-toluenesulfonic acid, naphthalene
Sulfonic acid, acetic acid, and methyl, ethyl, propyl,
Butyl, phenyl, methoxyphenyl, naphthyl, diph
Luorophenyl, pentafluorophenyl, thienyl,
Anionic organic acids such as organic boric acid having an organic group such as pyrrolyl
Can be mentioned. Among these, borate anions
Dyes with a counter ion have high solubility in coating solvents.
Since it is excellent, it is possible to use low boiling point solvents etc.
Are preferred.

As described above, the quinoline dyes represented by the general formulas (Ia to c), the indole or benzothiazole dyes represented by the general formula (II), and the imino compounds represented by the general formula (III). Cyclohexadiene dye, and the general formula (I
Specific examples of the pyrylium-based or thiapyrylium-based dyes represented by Va to c) are shown below.

[0039]

[Chemical 5]

[0040]

[Chemical 6]

[0041]

[Chemical 7]

[0042]

[Chemical 8]

[0043]

[Chemical 9]

[0044]

[Chemical 10]

[0045]

[Chemical 11]

[0046]

[Chemical 12]

[0047]

[Chemical 13]

[0048]

[Chemical 14]

Also, "special function pigments" (edited by Ikemori and Shiratani,
1986, published by CMC), "Chemistry of Functional Dyes" (edited by Higaki, 1981, published by CMC), "Dye Handbook" (edited by Taiga / Hirashima / Matsuoka / Kitao, published by Kodansha) , Japan Photosensitive Dye Research Institute 1995
Exciton Inc. Is 1
Laser dye catalog issued in 989, Epoli
n Inc. Catalog "Epo published in 1996 by
and the dyes having absorption in the near infrared region described in “Lite” and the like.
-123 "," NK-124 "," NK-2204 ",
"NK-2268", "NK-2545", "NK-2"
674 ”,“ NK-3027 ”,“ NK-3508 ”,
"NK-3555", "NKX-113", "NKX-"
114 "," NKX-1199 ", etc., Exciton
Inc. "IR-26", "IR-132", "IR
-140 "," DNTPC-P "," DNDTPC- "
P ”,“ Q-Switch5 ”, etc., Epolin In
c. "Epolite III-57", "Epolite III-57"
"ite III-117", "Epolite III-"
130 "," Epollite III-178 "," E "
Polite III-184 "," Epolite I "
II-189 "," Epolite III-19 "
2 "," Epolite IV-62A "," Epoli
te V-63 "," Epolite V-73 "," E
polite V-99 "," Epolite V-14 "
9 "and the like are preferable.

The content ratio of the photothermal conversion substance in the positive photosensitive composition of the present invention is preferably 1 to 70% by mass, particularly preferably 2 to 60% by mass,
It is more preferably 3 to 50% by mass.

Further, in the present invention, an alkali-soluble resin having a phenolic hydroxyl group is an essential component in the composition constituting the positive photosensitive layer. Examples of the alkali-soluble resin include, for example, novolac resin, resol resin, polyvinylphenol resin, copolymer of acrylic acid derivative having a phenolic hydroxyl group, and the like. Among them, novolac resin, resole resin, or polyvinylphenol resin is used. Novolak resin is particularly preferable.

The novolac resin is, for example, phenol,
o-cresol, m-cresol, p-cresol,
2,5-xylenol, 3,5-xylenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, propylphenol, n-butylphenol, tert-butylphenol, 1-naphthol, 2
-At least one phenol such as naphthol, 4,4'-biphenyldiol, bisphenol-A, pyrocatechol, resorcinol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, and phloroglucinol under acidic catalyst, Formaldehyde,
Aldehydes such as acetaldehyde, propionaldehyde, benzaldehyde, furfural (paraformaldehyde may be used in place of formaldehyde and paraaldehyde in place of acetaldehyde),
Or a resin polycondensed with at least one kind of ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, in which, in the present invention, phenol as phenols, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-
Xylenol, resorcinol and formaldehyde, acetaldehyde as aldehydes or ketones,
Polycondensates with propionaldehyde are preferred, in particular
The mixing ratio of m-cresol: p-cresol: 2,5-xylenol: 3,5-xylenol: resorcinol is 40 to 100: 0 to 5: 0 to 20: 0 to 2 in molar ratio.
Mixed phenols of 0: 0 to 20 or phenol:
A polycondensate of mixed phenols having a molar ratio of m-cresol: p-cresol of 1 to 100: 0 to 7: 0 to 60 and formaldehyde is preferable.

The novolak resin has a polystyrene-equivalent weight average molecular weight (MW) measured by gel permeation chromatography of preferably 1,000 to 1
5,000, particularly preferably 1,500 to 10,000
What is used.

Further, the resole resin is a resin polycondensed in the same manner except that an alkali catalyst is used in place of the acid catalyst in the polycondensation of the novolak resin, and in the present invention, it is the same as in the novolak resin. , Phenols and mixed compositions thereof, and aldehydes or ketones are preferable, and those having similar weight average molecular weight (MW) are also preferable.

The polyvinylphenol resin is, for example, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene,
Trihydroxystyrene, tetrahydroxystyrene,
Hydroxystyrenes such as pentahydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl) propylene, 2- (p-hydroxyphenyl) propylene (these are chlorine, bromine in the benzene ring). , Or a halogen atom such as iodine or fluorine, or an alkyl group having 1 to 4 carbon atoms as a substituent.) In the presence of a radical polymerization initiator or a cationic polymerization initiator. In the present invention, the benzene ring has 1 to 1 carbon atoms.
Polymers of hydroxystyrenes which may have the alkyl group of 4 as a substituent are preferable, and polymers of hydroxystyrenes having an unsubstituted benzene ring are particularly preferable.

The polyvinylphenol resin may be partially hydrogenated, or may be partially protected by a tert-butoxycarbonyl group, a pyranyl group, a furyl group or the like. Also, the weight average molecular weight (MW)
However, it is preferably 1,000 to 100,000, and particularly preferably 1,500 to 50,000.

If the molecular weight of the novolac resin, resol resin, or polyvinylphenol resin is smaller than the above range, a sufficient coating film as a resist cannot be obtained, and if it is larger than the above range, the solubility in an alkali developing solution is low. Therefore, it becomes difficult to obtain a resist pattern due to insufficient omission of the exposed portion.

The content ratio of the alkali-soluble resin in the positive photosensitive layer composition of the present invention is 30 to 99% by mass.
Is preferable, 40 to 98% by mass is particularly preferable, and 50 to 97% by mass is further preferable.

In the positive photosensitive layer composition of the present invention, a hydrogen bond is formed with the alkali-soluble resin for the purpose of increasing the difference in solubility between the exposed area and the unexposed area in an alkali developing solution. A dissolution inhibitor which has a function of decreasing the solubility of the polymer substance, absorbs almost no light in the near infrared region, and is not decomposed by light in the near infrared region may be contained.

Examples of the dissolution inhibitor include polyethylene glycols, polyethylene glycol polypropylene glycol block copolymers, polyethylene glycol alkyl ethers, polyethylene glycol polypropylene glycol alkyl ethers, polyethylene glycol alkylphenyl ethers, polyethylene glycol fatty acid esters. , Polyethylene glycol alkyl amines, polyethylene glycol alkyl amino ethers, glycerin fatty acid ester and its polyethylene oxide adducts, sorbitan fatty acid ester and its polyethylene oxide adduct, sorbit fatty acid ester and its polyethylene oxide adduct, pentaerythritol Fatty acid ester and its polyethylene Oxide adducts, nonionic surfactants such as polyglycerol fatty acid esters.

Further, sulfonic acid esters, phosphoric acid esters, aromatic carboxylic acid esters, aromatic disulfones, carboxylic acid anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers. Examples thereof include dyes having a lactone skeleton, N, N-diarylamide skeleton, diarylmethylimino skeleton, thiolactone skeleton, and sulfolactone skeleton.

In the above, as the dissolution inhibitor in the present invention, sulfonic acid esters, acid color-forming dyes having a lactone skeleton, and HLB of 10 or more, polyethylene glycols, polyethylene glycol polypropylene glycol block copolymers , Polyethylene glycol alkyl ethers, polyethylene glycol alkyl phenyl ethers, polyethylene glycol fatty acid esters, glycerin fatty acid ester and its polyethylene oxide adducts, sorbitan fatty acid ester and its polyethylene oxide adduct, sorbit fatty acid ester and its polyethylene oxide addition Nonionic surfactants such as substances, pentaerythritol fatty acid esters and polyglycerin fatty acid esters are preferred.

The content of the dissolution inhibitor in the photosensitive layer composition of the present invention is preferably 0 to 50% by mass, particularly preferably 0 to 30% by mass, and 0 to 20% by mass.
More preferably, it is% by mass.

The photosensitive layer composition of the present invention preferably contains an organic acid having a pKa of 2 or more and an anhydride of the organic acid for the purpose of improving developability such as imparting underdeveloping property. May be.

Examples of the organic acid and its anhydride are, for example, JP-A-60-88942 and JP-A-63-2760.
No. 48, JP-A-2-96754, etc. are used, and specifically, glyceric acid, methylmalonic acid, dimethylmalonic acid, propylmalonic acid, succinic acid, malic acid, meso-tartaric acid, Glutaric acid, β-methyl glutaric acid, β, β-dimethyl glutaric acid, β-ethyl glutaric acid, β, β-diethyl glutaric acid, β-propyl glutaric acid, β, β-methyl propyl glutaric acid, pimelic acid, suberin Acid, aliphatic saturated carboxylic acid such as sebacic acid, maleic acid, fumaric acid, aliphatic unsaturated carboxylic acid such as glutaconic acid, 1,1-cyclobutanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,1-cyclo Pentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,1-cyclohexanedicarboxylic acid, 1,
Carbocyclic saturated carboxylic acids such as 2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexenedicarboxylic acid, 2,3-dihydroxybenzoic acid, 3,
4-dimethylbenzoic acid, 3,4-dimethoxybenzoic acid,
3,5-dimethoxybenzoic acid, p-toluic acid, 2-hydroxy-p-toluic acid, 2-hydroxy-m-toluic acid, 2-hydroxy-o-toluic acid, mandelic acid, gallic acid, phthalic acid, isophthalic acid Acids, carbocyclic unsaturated carboxylic acids such as terephthalic acid, and Meldrum's acid,
Examples thereof include anhydrides such as ascorbic acid, succinic anhydride, glutaric anhydride, maleic anhydride, cyclohexene dicarboxylic acid anhydride, cyclohexane dicarboxylic acid anhydride and phthalic anhydride.

The content of the organic acid and the anhydride of the organic acid in the photosensitive layer composition of the present invention is preferably 0 to 30% by mass, particularly preferably 0 to 20% by mass, It is more preferably 0 to 10% by mass.

In addition to the above-mentioned components, the photosensitive layer composition of the present invention may contain, for example, a photosensitive composition such as a dye, a pigment, a coatability improving agent, an adhesion improving agent, a sensitivity improving agent, an oil sensitizing agent, and the like. Various commonly used additives may be further contained in a range of 20% by mass or less, preferably 10% by mass or less.

The photosensitive layer composition according to the present invention contains the photothermal conversion substance and the alkali-soluble resin as essential components, and is allowed to contain additives such as a dissolution inhibitor and a developability improving agent as described above. However, it does not contain an o-quinonediazide group-containing compound and is conventionally known as a positive photosensitive composition.
-Distinguished from compositions with quinonediazide group-containing compounds. That is, the conventional photosensitive layer composition containing an o-quinonediazide group-containing compound is an alkali-soluble resin alkali that is produced by photolysis of the diazo moiety of the o-quinonediazide group-containing compound by irradiation with ultraviolet light to generate a carboxylic acid. While it is believed that the solubility is increased and the exposed area is dissolved in an alkaline developing solution to form an image, the photosensitive layer composition of the present invention does not undergo such a chemical change due to exposure and is exposed to light heat. The light energy absorbed by the conversion substance is converted into heat, and the alkali-soluble resin in the part that receives the heat undergoes changes other than some chemical changes such as conformational changes, and the alkali-solubility of that part increases, so that alkali This is because it is considered that an image is formed by the developing solution.

The photosensitive layer composition of the present invention is usually prepared by applying a solution prepared by dissolving each of the above-mentioned components in a suitable solvent onto the surface of a support, followed by heating and drying to form a photosensitive composition on the surface of the support. Formed as a physical layer.

Here, the solvent is not particularly limited as long as it has a sufficient solubility for the components used and gives a good coating property, for example, methyl cellosolve,
Cellosolve solvent such as ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate Propylene glycol solvent such as dipropylene glycol dimethyl ether, butyl acetate, amyl acetate, ethyl butyrate, butyl butyrate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, methyl lactate, ethyl lactate, Ester solvent such as methyl 3-methoxypropionate, heptanol Hexanol, diacetone alcohol, alcohol solvents such as furfuryl alcohol, cyclohexanone, ketone solvents such as methyl amyl ketone,
Examples include highly polar solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, mixed solvents thereof, and those obtained by adding aromatic hydrocarbons to them. The proportion of the solvent used is usually in the range of about 1 to 20 times by weight with respect to the total amount of the photosensitive layer composition.

As the coating method, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, and curtain coating can be used. The coating amount varies depending on the application, but the dry film thickness is usually 0.3 to 7 μm.
m, preferably 0.5 to 5 μm, particularly preferably 1 to 3
The range is μm. The drying temperature at that time is, for example, about 60 to 170 ° C., preferably 70 to 150 ° C.
The drying time is about 5 seconds to 10 minutes, preferably about 10 seconds to 5 minutes.

For the purpose of improving the contrast during image formation and improving the temporal stability of image formability, for example, at a temperature of about 40 to 120 ° C., preferably about 40 to 70 ° C. for 5 minutes. It is preferable to carry out post heat treatment for about 100 hours, preferably for about 30 minutes to 75 hours.

Further, as the support, aluminum,
Metal plates such as zinc, copper, steel, aluminum, zinc, copper,
Metal plate plated or vapor-deposited with iron, chromium, nickel, etc.,
Examples thereof include paper, resin-coated paper, paper on which a metal foil such as aluminum is attached, a plastic film, a hydrophilized plastic film, and a glass plate. Inside,
Preferred is an aluminum plate, which has been subjected to surface treatment such as graining treatment by electrolytic etching or brush polishing in hydrochloric acid or nitric acid solution, anodizing treatment in sulfuric acid solution, and sealing treatment if necessary. An aluminum plate is more preferable. The surface roughness of the support is JIS B0.
The average roughness Ra defined in 601 is usually 0.3 to
The thickness is 1.0 μm, preferably 0.4 to 0.8 μm.

The light source for imagewise exposing the photosensitive composition layer in the present invention is mainly a HeNe laser, an argon ion laser, a YAG laser, a HeCd laser,
A laser light source such as a semiconductor laser or a ruby laser can be used. Particularly, in the case of forming an image by heat generated by absorbing light, a light source which generates a near infrared laser beam of 650 to 1300 nm is preferable, and for example, ruby. Solid-state lasers such as lasers, YAG lasers, semiconductor lasers and LEDs can be mentioned, and particularly small and long-lived semiconductor lasers and YAG lasers are preferable. Scanning exposure is usually performed with these light sources, and then the image is formed by developing with the above-mentioned developing solution.

The laser light source normally scans the surface of the photosensitive composition layer as a high-intensity light beam (beam) focused by a lens, and the sensitivity of the photosensitive composition layer in the present invention is sensitive to the light beam. The characteristic (mJ / cm ² ) may depend on the light intensity (mJ / s · cm ² ) of the received laser beam. Here, for the light intensity of the laser beam, the amount of energy (mJ / s) of the laser beam measured by an optical power meter per unit time is divided by the irradiation area (cm ² ) of the laser beam on the surface of the photosensitive composition layer. It can be obtained by The irradiation area of the laser beam is usually defined as the area of a portion exceeding 1 / e ² intensity of the laser peak intensity, but it can be simply measured by exposing a photosensitive composition showing a reciprocity law to light. . In the present invention, the light intensity of the light source is 2.0 × 10 ⁶ m
J / s · cm ² or more is preferable, 1.0 × 1
It is particularly preferable to set it to 0 ⁷ mJ / s · cm ² or more. When the light intensity is in the above range, the sensitivity characteristic of the photosensitive composition layer in the present invention can be improved, and the scanning exposure time can be shortened, which is a great advantage in practical use.

[0076]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples unless it exceeds the gist thereof. (Examples 1 to 32, Comparative Examples 1 to 6) (Preparation of photosensitive lithographic printing plate A) An aluminum plate (thickness: 0.24 mm) was placed in a 3 mass% sodium hydroxide bath for 6 times.
After degreasing treatment at 0 ° C. for 1 minute, electrolytic etching treatment was performed at 25 ° C. at a current density of 80 A / dm ² for 10 seconds in a hydrochloric acid bath having a concentration of 12 g / liter, and after washing with water, 10 g / liter
Desmut treatment is carried out at 50 ° C. for 3 seconds in a sodium hydroxide bath having a concentration of 1 liter, followed by washing with water and then 3 times in a 30% by mass sulfuric acid bath.
Anodizing treatment was performed at 0 ° C. and a current density of 10 A / dm ² for 15 seconds. Further, hot water sealing treatment was carried out at 90 ° C. and pH 9, washed with water and dried to prepare an aluminum plate for a lithographic printing plate support.

On the surface of the obtained aluminum plate support, 4 parts by weight of the indole dye (“CY-10” manufactured by Nippon Kayaku Co., Ltd.) shown in the above-mentioned specific example (II-8) as a light-heat converting substance,
As an alkali-soluble resin, 100 parts by weight of a novolac resin (MW 9400, manufactured by Sumitomo Dures Co., Ltd.) obtained by polycondensing a mixed phenol of phenol / m-cresol / p-cresol = 50/30/20 (molar ratio) with formaldehyde, dissolution inhibiting 4 parts by weight of polyethylene glycol ("PEG # 2000" manufactured by Toho Chemical Industry Co., Ltd.) as an agent, and 5 parts by weight of 1,2-cyclohexanedicarboxylic acid as a developability improving agent are dissolved in 1000 parts by weight of methyl cellosolve. Apply the applied coating solution using a wire bar, and
By drying at 5 ℃ for 3 minutes, the dry film thickness is 2.5.
Photosensitive planographic printing plate A having a photosensitive composition layer of g / m ^2.
Was produced.

(Preparation of photosensitive lithographic printing plate B) Thickness 0.3
A mm aluminum plate (material 1050) was degreased by washing with trichlorethylene, and then its surface was grained using a nylon brush and a 400 mesh pumisu water suspension, and thoroughly washed with water. This plate was immersed in a 25% by mass aqueous sodium hydroxide solution at 45 ° C for 9 seconds for etching, washed with water, and then further immersed in 20% by mass nitric acid for 20 seconds,
Washed with water. At this time, the etching amount of the grained surface is about 3
It was g / m ² . Next, this plate was provided with a DC anodic oxide coating of 3 g / m ² at a current density of 15 A / dm ² using 7% by mass sulfuric acid as an electrolyte, washed with water, dried, and further coated with the following undercoating solution to obtain a coating. The membrane was dried at 90 ° C for 1 minute. The coating amount of the coating film after drying was 10 mg / m ² . The following photosensitive solution B was applied to the obtained substrate and dried at 100 ° C. for 2 minutes to form a photosensitive lithographic printing plate B. The coating amount of the coating film after drying was 2 g / m ² .

[0079] [Undercoat liquid] ・ The following compound 0.3g ・ Methanol 100g ・ Water 1g

[0080]

[Chemical 15]

[0081] [Photosensitive solution B] m, p-cresol novolac (m / p ratio = 6/4, weight average molecular weight 0.75 g 7500, containing 0.5% by mass of unreacted cresol) The following cyanine dye A 0.04 g p-toluenesulfonic acid 0.002 g Tetrahydrophthalic anhydride 0.05 g Victoria Pure Blue BOH 0.015g counter anion Dyes with 1-naphthalene sulfonate anion Fluorine-based surfactant (MegaFac F-176, 0.02 g Dainippon Ink and Chemicals Co., Ltd.) γ-butyl lactone 8 g Methyl ethyl ketone 7 g 1-methoxy-2-propanol 7 g

[0082]

[Chemical 16]

For the obtained photosensitive lithographic printing plates A and B, a laser exposure machine (manufactured by Creo, “Trendse”) was used.
Table 1 after exposure at 200 mj / cm ²
When the lithographic printing plate having the composition shown in (1) was developed with an undeveloped developer, the film slippage in the image area at the time when the exposed area was completely removed is shown in Table 1 as the film slippage at the start.
Further, in the case of a film having no film slippage, the longest time in which the exposed portion was completely removed and the residual film ratio of the non-exposed portion was maintained at 90% or more was measured. FUJIFILM automatic developing machine 900NP (developing solution tank capacity 22.5 liters) was used, the developing time was set to the maximum time, and 150 cc of the developing solution shown in Table 1 was added per 1 m ^{2 of} treatment.
The lithographic printing plate, which was entirely exposed under the above exposure conditions, was set to 300 cc per hour under the setting of replenishing the developing solution of 200 cc per hour.
After development by an amount corresponding to m ^2, the residual film ratio of the non-exposed area of the image-wise exposed lithographic printing plate was measured, and 90% or more was evaluated as “no film slippage in the image area during running”. still,
The residual film ratio is based on the reflection density of the support before coating the photosensitive layer, and is the reflection density before and after development in the non-exposed area when the development is performed by rubbing 5 times with a sponge after dipping at 28 ° C. for 60 seconds. It was measured with a Macbeth reflection densitometer and calculated from the ratio of the reflection densities.

The surfactants used in the developing solutions shown in Table 1 are as follows. Cationic surfactant (1); "Surflon S" manufactured by Asahi Glass Co., Ltd.
-121 "(quaternary ammonium salt) Cationic surfactant (2);" Texn "manufactured by Nippon Emulsifier Co., Ltd.
ol R5 "(quaternary ammonium salt) cationic surfactant (3); Sumitomo 3M's" Florard FC-135 "(quaternary ammonium salt) nonionic surfactant (1); Asahi Denka Co., Ltd. Pluronic P-84 "(polyethylene oxide derivative) nonionic surfactant (2); Asahi Denka Co., Ltd." Pluronic P-85 "(polyethylene oxide derivative) nonionic surfactant (3); Asahi Denka" Pluronic P " -88 "(polyethylene oxide derivative) nonionic surfactant (4); Asahi Denka Co., Ltd." Pluronic TR-701 "(polyethylene oxide derivative) nonionic surfactant (5); Asahi Denka" Pluronic TR-702 " (Polyethylene oxide derivative) Nonionic surfactant (6); "Neugen EA-120" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. (polyethylene) Oxide derivatives) nonionic surfactant (7); manufactured by Nippon Nyukazai Co. "Newc
ol 723 ”(polyethylene oxide derivative) nonionic surfactant (8); manufactured by Kao“ Emulgen A-
500 "(Polyethylene oxide derivative) Nonionic surfactant (9);" Nissan P "manufactured by NOF Corporation
EG200 "(polyethylene oxide) Nonionic surfactant (10);" Nissan P "manufactured by NOF Corporation
EG400 ”(polyethylene oxide) amphoteric surfactant (1); Daiichi Kogyo Seiyaku Co., Ltd.“ Amogen K ”(betaine type compound)

[0085]

[Table 1]

[0086]

According to the present invention, the contrast between the image area and the non-image area is excellent, and the residual film ratio in the image area is sufficiently maintained. Therefore, the photosensitive lithographic printing plate having a wide range of stable developing conditions for a long period of time. It is possible to provide a method for developing a printing plate and a developer used for the method.

Claims (3)

[Claims] 1. A lithographic printing plate precursor having a photosensitive layer containing a photothermal conversion substance and an alkali-soluble resin having a phenolic hydroxyl group, which has a pH of at least 12 after laser exposure.
A method of making a printing plate, which comprises developing with an aqueous solution containing an amount of a surfactant exceeding 0000 ppm, an alkali metal hydroxide and an alkali metal silicate. 2. The method of making a printing plate according to claim 1, wherein a replenisher is added so that the amount of the surfactant during running the aqueous solution during development exceeds 10,000 ppm. 3. A developer for use in making a printing plate by developing a lithographic printing plate precursor having a photosensitive layer containing a photothermal conversion substance and an alkali-soluble resin having a phenolic hydroxyl group, after laser exposure. With a pH of 12 or higher,
A developing solution comprising a surfactant, an alkali metal hydroxide and an alkali metal silicate in an amount exceeding 10,000 ppm.