JP2002318452A - Positive photosensitive composition, positive photosensitive planographic printing plate and positive image forming method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive photosensitive composition having high sensitivity to light in the near IR region, excellent in contrast between image and non-image areas and ensuring wide development conditions as a positive photosensitive composition comprising a photothermal conversion material and an alkali-soluble resin and to provide a positive photosensitive planographic printing plate and a positive image forming method using the printing plate. SOLUTION: The positive photosensitive composition contains (A) a photothermal conversion material which absorbs light of a light source for imagewise exposure and converts it to heat, (B) a novolak resin, (C) a surfactant and (D) a phosphonium compound. The positive type photosensitive planographic printing plate is obtained by forming a layer of the positive type photosensitive composition on the surface of a substrate. In the positive image forming method, the positive photosensitive planographic printing plate is subjected to scanning exposure with laser light in the wavelength range of 650-1,300 nm and developed with an alkali developing solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to photosensitive lithographic printing plates, proofs for simple proof printing, copper etching resists for wiring boards and gravure, resists for color filters used in flat display manufacturing, photoresists for LSI manufacturing, etc. Positive photosensitive composition used, which is highly sensitive mainly to light in the near-infrared region, particularly a positive photosensitive composition suitable for direct plate making with a semiconductor laser or a YAG laser, and a positive photosensitive composition. Photosensitive lithographic printing plate and a positive image forming method using the same.

[0002]

2. Description of the Related Art Conventionally, as a positive photosensitive composition, for example, an o-quinonediazide group-containing compound which forms indenecarboxylic acid upon irradiation with light and becomes alkali-soluble,
An organic polymer substance having an o-nitrocarbinol ester group, or a composition of a compound that generates an acid by light (photoacid generator) and a compound that is hydrolyzed by an acid and becomes alkali-soluble is known. I have.

On the other hand, with the advance of computer image processing technology, photosensitive or heat-sensitive direct plate making in which a resist image is directly formed by laser light or a thermal head without outputting digital image information to a silver halide mask film. The system is drawing attention. In particular, the realization of a high-resolution laser-sensitive direct plate making system using a high-output semiconductor laser or YAG laser is strongly desired in terms of miniaturization, environmental light during plate making work, and plate material cost. I have.

On the other hand, conventionally, as an image forming method using 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. For the latter, specifically, for example, a method of preparing a lithographic printing plate using a crosslinking reaction of a diazo compound, a method of preparing a lithographic printing plate using a decomposition reaction of nitrocellulose, and the like are known.

[0005] In recent years, a technique in which a long-wavelength light-absorbing dye is combined with a chemically amplified photoresist has been scattered. For example, JP-A-6-43633 discloses a specific squarylium-based dye, a photoacid generator, and a binder. And JP-A-7-20629 discloses a positive composition containing an infrared absorbing dye, a latent Bronsted acid, a resole resin, and a novolak resin. No. 271029 discloses a positive composition using an s-triazine-based compound in place of the latent Bronsted acid. Further, JP-A-7-285275 discloses
A positive composition comprising a binder, a substance that absorbs light and generates heat, and a substance that is thermally decomposable and substantially degrades the solubility of the binder when not decomposed, is disclosed, respectively. I have.

In addition, these conventional techniques have a disadvantage that they are sensitive to light in the ultraviolet region, and the reaction proceeds during handling under a white fluorescent lamp, so that it is difficult to obtain a product of stable quality. In contrast, Japanese Patent Application Laid-Open No. 9-438
No. 47 discloses a positive composition containing a resin which is hardly soluble in an alkali developing solution and an infrared absorbing agent, which is heated by infrared irradiation or the like to change crystallinity and becomes alkali-soluble, but does not change by ultraviolet irradiation. Things are also WO97 / 39
No. 894, a heat-sensitive positive type composition containing an aqueous developable polymer and a compound which inhibits the aqueous developability of the polymer, the aqueous developability of which is improved by heating but which is not changed by ultraviolet irradiation. Each disclosed, and also the applicant of the present application, can not expect a photochemical change of a photothermal conversion material consisting of a near infrared absorbing dye having a structure in which a heteroatom is bonded via a polymethine chain and an alkali-soluble resin such as a novolak resin. It has been found that a positive composition which can solve the above-mentioned disadvantages can be obtained with a simple system, and a patent application (see JP-A-10-268512) has been made.

[0007] Japanese Unexamined Patent Publication No. 9-43847, WO
97/39894, and JP-A-10-2684
The positive-working composition disclosed in Japanese Patent Publication No. 12-112, contains a compound that undergoes a chemical change upon exposure, and causes a difference in solubility between exposed and unexposed areas due to the chemical change. Unlikely, because it causes differences in solubility due to changes other than chemical changes, and because it does not contain compounds that are sensitive to light in the ultraviolet region,
It has advantages such as excellent handleability under a white fluorescent lamp.

However, according to the study of the present inventors,
The positive type composition in the prior art has an image area (non-exposed area)
And the contrast between the non-image portion (exposed portion) and the non-image portion (exposed portion) is insufficient. As a result, there is a problem that the removability of the non-image portion is insufficient or the residual film ratio of the image portion is not sufficiently maintained. Yes,
In particular, Japanese Unexamined Patent Application Publication No. 9-4384 discloses a method that causes a difference in solubility between an exposed portion and a non-exposed portion by a change other than a chemical change.
No. 7, WO97 / 39894, and Japanese Patent Application Laid-Open No. 10-268512, it was found that the tendency was remarkable.

On the other hand, in order to solve these problems, for example, Japanese Patent Laid-Open No. 2000-105454 discloses a positive composition containing a surfactant such as a nonionic surfactant. According to the study by the present inventors, it has been found that the problem still remains.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art. Accordingly, the present invention relates to a positive-type photosensitive composition comprising a light-to-heat conversion material and an alkali-soluble resin. High sensitivity to light in the region, excellent in contrast between the image area and the non-image area, and therefore, a positive photosensitive composition having a wide range of development conditions, and
An object of the present invention is to provide a positive photosensitive lithographic printing plate and a positive image forming method using the same.

[0011]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that the above object can be achieved by including a specific dissolution inhibitor in the photosensitive composition. The present invention has been completed, that is, the present invention provides the following component (A), component (B), component (C),
And a positive photosensitive lithographic printing plate comprising a support having thereon a layer of the positive photosensitive composition, and a positive photosensitive lithographic printing plate comprising a support having thereon a layer of the positive photosensitive composition. The present invention provides a positive image forming method in which a photosensitive lithographic printing plate is scanned and exposed with a laser beam having a wavelength range of 650 to 1,300 nm, and then developed with an alkali developing solution. (A) a photothermal conversion material that absorbs light from an image exposure light source and converts it into heat (B) novolak resin (C) surfactant (D) phosphonium compound

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As the photothermal conversion component (A) contained in the positive photosensitive composition of the present invention, any compound capable of absorbing light from an image exposure light source and converting it into heat can be used. Although not limited, a light-absorbing dye having an absorption band in part or all of the wavelength range of 650 to 1,300 nm is particularly effective. These light-absorbing dyes efficiently absorb light in the above-mentioned wavelength region, but hardly absorb light in the ultraviolet region, or do not substantially respond to absorption, and are weakly sensitive to ultraviolet light contained in white lamps. Is a compound having no action of modifying the photosensitive composition.

In the present invention, these light-absorbing dyes have a structure in which a heteroatom such as a nitrogen atom, an oxygen atom, or a sulfur atom is bonded by a polymethine (—CH ＝) _n chain. Means that the heteroatoms form a heterocycle,
A so-called structure in which a heterocycle is bonded via a polymethine chain,
Cyanine-based dyes in a broad sense, specifically, for example, quinoline-based (so-called cyanine-based in a narrow sense), indole-based (so-called,
Indocyanine-based), benzothiazole-based (so-called thiocyanine-based), pyrylium-based, thiapyrylium-based, squarylium-based, croconium-based, azurenium-based, and the like, and so-called structures in which acyclic heteroatoms are bonded via a polymethine chain. And polymethine dyes, among which cyanine dyes such as quinoline, indole, benzothiazole, pyrylium, and thiapyrylium dyes, and polymethine dyes are preferable.

Other typical examples include diiminium dyes and phthalocyanine dyes, among which diiminium dyes are preferred.

In the present invention, among the cyanine-based dyes, quinoline-based dyes include those represented by the following general formula (I)
Those represented by a), (Ib) or (Ic) are preferred.

[0016]

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[In the formulas (Ia), (Ib) and (Ic), R ¹ and R
² each independently has 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 group which has a substituent. L ¹ represents a tri, penta, hepta, nona, or undecamethine group which may have a substituent, and two substituents on the penta, hepta, nona, or undecamethine group Are linked to each other to have 5 to 7 carbon atoms
May form a cycloalkene ring, a cycloalkeneone ring, a cycloalkenedione ring, or a cycloalkenethione ring, and the quinoline ring may have a substituent,
In that case, two adjacent substituents may be connected to each other to form a fused benzene ring. Xa ^- represents a counter anion. ]

Here, R ¹ in the formulas (Ia), (Ib) and (Ic)
And when R ² is an alkyl group, the number of carbon atoms is usually 1 to 1
5, preferably 1 to 10, the number of carbon atoms when it is an alkenyl group or an alkynyl group is usually 2 to 15, preferably 2 to 1.
0, as those substituents including phenyl groups, from 1 to 15 carbon atoms, preferably 1 to 10 alkoxy group, a phenoxy group, hydroxy group, or a phenyl group and the like, in L ¹ Examples of the substituent include an alkyl group having the same number of carbon atoms, an amino group, and a halogen atom.Examples of the substituent in the quinoline ring include an alkyl group having the same number of carbon atoms, an alkoxy group having the same number of carbon atoms, a nitro group, and a halogen atom. Atoms and the like.

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

[0020]

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[In the formula (II), Y ¹ and Y ² each independently represent a dialkylmethylene group or a sulfur atom, and R ³ and R ⁴ each independently may have a substituent. An alkyl group, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, or a phenyl group which may have a substituent, and L ² has a substituent Represents a tri, penta, hepta, nona, or undecamethine group which may be substituted, and two substituents on the penta, hepta, nona, or undecamethine group are linked to each other to have 5 carbon atoms.
To 7 may form a cycloalkene ring, a cycloalkeneone ring, a cycloalkenedione ring, or a cycloalkenethione ring, and the fused benzene ring may have a substituent. The substituents may be linked to each other to form a fused benzene ring. Xa ^- represents a counter anion. ]

Here, when R ³ and R ⁴ in the formula (II) are alkyl groups, the number of carbon atoms is usually 1 to 15, preferably 1 to 15.
, An alkenyl group or an alkynyl group usually has 2 to 15 carbon atoms, preferably 2 to 10 carbon atoms.
To 15, preferably 1 to 10, an alkoxy group, a phenoxy group, a hydroxy group, or a phenyl group.
^As the substituent in ² , an alkyl group having the same number of carbon atoms as above,
Examples of an amino group or a halogen atom include substituents on the condensed benzene ring, such as an alkyl group having the same carbon number, an alkoxy group having the same carbon number, a nitro group, and a halogen atom.

Further, as the pyrylium-based and thiapyrylium-based dyes, the following general formulas (IIIa), (IIIb) and
Those represented by (IIIc) are preferred.

[0024]

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[In the formulas (IIIa), (IIIb) and (IIIc), Z ¹
And Z ² each independently represent an oxygen atom or a sulfur atom; R ⁵ , R ⁶ , R ⁷ , and R ⁸ each independently represent a hydrogen atom or an alkyl group, or R ⁵ and R ⁷ , and R ⁶ and R
⁸ may be linked to each other to form a cycloalkene ring having 5 or 6 carbon atoms, and L ³ represents a mono, tri, penta, or heptamethine group which may have a substituent; Two substituents on a penta or heptamethine group may be linked to each other to form a cycloalkene ring having 5 to 7 carbon atoms, a cycloalkeneone ring, a cycloalkenedione ring or a cycloalkenethione ring, and a pyrylium ring And the thiapyrylium ring may have a substituent, in which case, two adjacent substituents may be connected to each other to form a fused benzene ring. Xa ^- represents a counter anion. ]

Here, when R ⁵ , R ⁶ , R ⁷ and R ⁸ in the formulas (IIIa), (IIIb) and (IIIc) are alkyl groups, the number of carbon atoms is usually 1 to 15, preferably 1 to 15. 1 to 10,
The substituent in L ^3, ibid alkyl group of carbon number, an amino group, or a halogen atom, and examples of the substituent in the pyrylium ring and thiapyrylium ring,
And an aryl group such as a phenyl group and a naphthyl group.

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

[0028]

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[In the formula (IV), R ⁹ , R ¹⁰ , R ¹¹ and R ¹²
Each independently represents an alkyl group; R ¹³ and R ¹⁴ each independently represent an aryl group, a furyl group, or a thienyl group which may have a substituent; and L ⁴ represents a substituent. Represents a mono, tri, penta, or heptamethine group which may be substituted, and the two substituents on the tri, penta, or heptamethine group are connected to each other to form a cycloalkene ring having 5 to 7 carbon atoms, a cycloalkene ring, A cycloalkenedione ring or a cycloalkenethione ring may be formed, and the quinone ring and the benzene ring may have a substituent. Xa
^- represents a counter anion. ]

The alkyl group of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² in the formula (IV) generally has 1 to 15, preferably 1 to 10, and R ¹³ and R ¹⁴ are aryl groups. Is usually from 6 to 20, preferably from 6 to 15, and R ¹³
And R ¹⁴ specifically include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-furyl group, a 3-furyl group,
-Thienyl group, 3-thienyl group, and the like. Examples of the substituent include an alkyl group having the same number of carbon atoms, an alkoxy group having the same number of carbon atoms, a dialkylamino group, a hydroxy group,
Or a halogen atom. Examples of the substituent in L ⁴ include an alkyl group having the same carbon number as described above, an amino group, and a halogen atom. Examples of the substituent in the quinone ring and the benzene ring include an alkyl group having the same number of carbon atoms as described above. Groups, alkoxy groups having the same number of carbon atoms, nitro groups, and halogen atoms.

Further, as the diiminium-based dye, a dye represented by the following formula (Va) or (Vb) having at least one N, N-diaryliminium salt skeleton is particularly preferable.

[0032]

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In the formulas (Va) and (Vb), R¹⁵, R¹⁶,
R¹⁷, And R¹⁸Are each independently a hydrogen atom, a halogen atom
A substituent, an alkyl group which may have a substituent,
An alkenyl group which may have a substituent
Alkynyl group or an optionally substituted alkynyl group
A xy group;¹⁹, And R²⁰Is each independently a substituent
An alkyl group which may have
Good alkenyl group, alkynyl optionally having substituent (s)
Group, an optionally substituted alkoxy group, a substituent
Having an acyloxy group or a substituent which may have
Represents a phenyl group which may be
The quinone ring may have a substituent. Xa ^-Is ani
Indicates ON. Note that the electron bond (dotted line) in the formula (Vb)
4 shows a resonance state with a child bond. ]

Here, R ¹⁵ in the formulas (Va) and (Vb),
When R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ , and R ²⁰ are an alkyl group or an alkoxy group, the number of carbon atoms is usually 1 to 15, preferably 1 to 10, and the number of carbon atoms when an alkenyl group or an alkynyl group is used. Is usually 2 to 15, preferably 2 to 10, and the substituents therein include an alkyl group having the same number of carbon atoms, an alkoxy group having the same number of carbon atoms, a carboxy group, an acyloxy group, an alkoxycarbonyl group, a hydroxy group, and an amino group. An alkylamino group, a halogenated alkyl group, or a halogen atom.Examples of the substituent on the benzene ring and the iminoquinone ring include an alkyl group having the same carbon number, an alkoxy group having the same carbon number, an acyl group, a nitro group,
Or a halogen atom.

Among these diiminium-based dyes, R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁵ in the above formulas (Va) and (Vb)
It is particularly preferred that ¹⁸ is an alkyl group and R ¹⁹ and R ²⁰ are also alkyl groups, or that R ¹⁹ and R ²⁰ are phenyl groups having a dialkylamino group as a substituent.

The compounds represented by the general formulas (Ia-c), (II), (IIIa-
c), the counter anion Xa in (IV) and (Va-b)^-age
For example, Cl^-, Br^-, I^-, ClO_Four ^-, P
F₆ ^-, SbF₆ ^-, AsF₆ ^-And BF_Four ^-, B
Cl_Four ^-Inorganic acid anions such as inorganic boric acid, etc .;
Benzenesulfonic acid, toluenesulfonic acid, naphthalene
Sulfonic acid, acetic acid, and methyl, ethyl, propyl,
Tyl, phenyl, methoxyphenyl, naphthyl, fluoro
Rophenyl, difluorophenyl, pentafluorophen
Organic boric acid having an organic group such as nil, thienyl and pyrrolyl
And the like. Among these
The dye having a borate anion as a counter ion is a coating solvent.
Excellent solubility in water, so low-boiling solvents can be used
It is preferable because it becomes functional.

The quinoline compounds represented by the above formulas (Ia to c), the indole compounds or benzothiazole compounds represented by the above formula (II), and the pyrylium compounds represented by the above formulas (IIIa to c) Or cyanine dyes such as thiapyrylium,
Among the polymethine dyes represented by the general formula (IV), and the diiminium dyes represented by the general formulas (Va to b),
In the present invention, an indole or benzothiazole cyanine dye represented by the general formula (II) is particularly preferable.

The quinoline compounds represented by the general formulas (Ia to c), the indole compounds represented by the general formula (II) or the benzothiazole compounds, and the pyrylium compounds represented by the general formulas (IIIa to c) Specific examples of a cyanine dye such as a dye or a thiapyrylium dye, a polymethine dye represented by the general formula (IV), and a diiminium dye represented by the general formula (Va to b) are shown below.

[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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[0045]

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[0046]

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[0047]

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[0048]

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[0049]

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In the positive photosensitive composition of the present invention, the content ratio of the photothermal conversion material of the component (A) is 0.5 to 50.
%, More preferably from 0.5 to 30% by weight, particularly preferably from 1 to 20% by weight.

The novolak resin (B) contained in the positive photosensitive composition of the present invention includes, 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-naphthol, pyrocatechol, resorcinol, hydroquinone, pyrogallol, 1,2,4-benzenetriol, phloroglucinol, 4,4'-biphenyldiol, 2,2-bis (4'-hydroxyphenyl)
At least one of phenols such as propane is reacted with an acidic catalyst, for example, formaldehyde, acetaldehyde,
Aldehydes such as propionaldehyde, benzaldehyde and furfural (paraformaldehyde may be used instead of formaldehyde and paraaldehyde may be used instead of acetaldehyde), or ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Which is polycondensed with at least one of the above, and is commonly used as a binder resin of the photosensitive composition.

Among the novolak resins in the present invention, phenols such as phenols, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-xylenol, resorcinol, aldehydes or Polycondensates with formaldehyde, acetaldehyde and propionaldehyde as ketones are preferred, and particularly m-cresol: p-cresol:
The mixing ratio of 2,5-xylenol: 3,5-xylenol: resorcinol is 40 to 100: 0 to 5 in molar ratio.
A mixed phenol of 0: 0 to 20: 0 to 20: 0 to 20 or a mixing ratio of phenol: m-cresol: p-cresol is 1 to 100: 0 to 70: 0 to 6 in a molar ratio.
0 or a mixed phenol having a molar ratio of o-cresol: phenol: m-cresol: p-cresol of 1 to 60: 1 to 80: 0 to 50: 0 to 50, and formaldehyde Is preferred.

The novolak resin of the present invention has a weight average molecular weight of 1,000 to 1,000 in terms of polystyrene measured by gel permeation chromatography.
It is preferably 15,000,
It is particularly preferred that it is 10,000. If the weight average molecular weight is less than the above range, a sufficient coating film cannot be obtained, while if the weight average molecular weight exceeds the above range, the solubility in an alkali developing solution becomes small, and it is difficult to obtain a positive image due to insufficient omission of a non-image portion. It tends to be.

The content of the novolak resin of the component (B) in the positive photosensitive composition of the present invention is from 10 to 95.
%, Preferably from 20 to 95% by weight, more preferably from 40 to 90% by weight.

The positive photosensitive composition of the present invention may contain a carboxyl group-containing vinyl resin in combination with the component (B) novolak resin as a binder resin. Examples of the base resin include (meth) acrylic acid, crotonic acid, isocrotonic acid, maleic acid, maleic anhydride, itaconic acid,
Unsaturated carboxylic acids such as citraconic acid, styrene, α-
Methyl styrene, hydroxy styrene, methyl (meth)
Acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate,
Pentyl (meth) acrylate, hexyl (meth) acrylate, dodecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) Acrylate, N, N-dimethylaminoethyl (meth) acrylate, N- (meth) acryloylmorpholine, (meth) acrylonitrile, (meth) acrylamide, N-methylol (meth) acrylamide, N, N-
Dimethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, copolymers with vinyl compounds such as vinyl acetate, and the like. These carboxyl group-containing vinyl resins have an acid value of 30 to 250 KOH.
Mg / g, weight average molecular weight in terms of polystyrene is 1,
It is preferably from 000 to 300,000.

The surfactant (C) contained in the positive photosensitive composition of the present invention has functions as a sensitivity improver, a developability improver, and the like. Nonionic, anionic, or amphoteric surfactants used in the lipophilic composition are used.

Examples of the nonionic surfactant include polyethylene glycols such as polyethylene glycol and polyethylene glycol polypropylene glycol block copolymer, polyethylene glycol cetyl ether, polyethylene glycol stearyl ether, polyethylene glycol oleyl ether, polyethylene glycol behenyl ether and the like. Polyethylene glycol polypropylene glycol alkyl ethers such as polyethylene 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 Polyethylene glycol alkyl phenyl ethers such as ter, ethylene glycol monostearate, ethylene glycol distearate, diethylene glycol stearate, polyethylene glycol distearate, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol such as polyethylene glycol monooleate Fatty acid esters, glyceryl monomyristate, glyceryl monostearate, glyceryl monoisostearate, glyceryl distearate, glyceryl monooleate, glyceryl dioleate and the like, and their polyethylene oxide adducts and polyglycerin fatty acid esters , Pentaerythritol monostearate, bird Stearate pentaerythritol monooleate and pentaerythritol,
Pentaerythrit fatty acid esters such as pentaerythritol trioleate, and polyethylene oxide adducts thereof, sorbitan monopalmitate, sorbitan monostearate, sorbitan tristearate, sorbitan monooleate, sorbitan trioleate, etc. Fatty acid esters, and their polyethylene oxide adducts, sorbitol monolaurate, sorbit tetrastearate, sorbit hexastearate, sorbit tetraoleate, and the like, and their oxidized fatty acid esters, polyethylene oxide adducts, and polyethylene glycol alkylamines , Polyethylene glycol alkyl amino ethers, castor oil polyethylene oxide adducts, lanolin with polyethylene oxide Mention may be made of things, and the like.

Also, as the anionic surfactant,
For example, sodium laurate, sodium stearate, higher fatty acid salts such as sodium oleate, alkyl sulfonates such as sodium lauryl sulfonate,
Alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, alkylnaphthalene sulfonates such as sodium isopropylnaphthalenesulfonate, alkyldiphenylether disulfonates such as sodium alkyldiphenyletherdisulfonate,
Polyoxyethylene alkyl ether sulfonates such as sodium polyoxyethylene lauryl ether sulfonate, alkyl sulfates such as sodium lauryl sulfate and sodium stearyl sulfate, sodium octyl alcohol sulfate, sodium lauryl alcohol sulfate, ammonium lauryl alcohol sulfate Higher alcohol sulfates such as sodium acetyl alcohol sulfate, sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene lauryl ether ammonium sulfate, polyoxyethylene lauryl ether triethanolamine sulfate and the like. Ethylene alkyl ether sulfates, polyoxyethylene nonylphenyl Polyoxyethylene alkyl phenyl ether sulfates such as sodium tere sulfate, alkyl phosphate salts such as sodium lauryl phosphate and sodium stearyl phosphate, and polyoxyethylene alkyl ethers such as sodium polyoxyethylene lauryl ether and sodium polyoxyethylene stearyl ether phosphate. Phosphates, polyoxyethylene alkyl phenyl ether phosphates such as sodium polyoxyethylene nonyl phenyl ether phosphate, sulfosuccinic acids, unsaturated fatty acid sulfated oils, taurine salts, castor oil sulfate salts and the like can be mentioned.

Examples of the amphoteric surfactant include N-lauryl-N, N-dimethyl-N-carboxymethylammonium, N-stearyl-N, N-dimethyl-N-carboxymethylammonium and N-lauryl. Betaine-type compounds such as -N, N-dihydroxyethyl-N-carboxymethylammonium, N-lauryl-N, N, N-tris (carboxymethyl) ammonium, 2-alkyl-N-carboxymethyl-N-hydroxyethyl Examples thereof include imidazolium salts such as imidazolium, imidazolines such as imidazoline-N-sodium ethylsulfonate, imidazoline-N-sodium ethylsulfate, aminocarboxylic acids, and aminosulfates.

Among these surfactants, nonionic surfactants are preferable, and the following general formulas (VI), (VII) and (VII)
Nonionic surfactants represented by (I), (IX) and (X) are particularly preferred.

[0061]

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[Formulas (VI), (VII), (VIII), (IX), and
In (X), R ^{21 to} R ³² represent a hydrocarbon group, and p, q1 to q6,
r and s1 to s4 are each independently an integer of 1 to 100. ]

Here, the hydrocarbon group of R ^{21 to} R ³² is preferably an aliphatic hydrocarbon group such as an alkyl group, an alkenyl group, an alkadienyl group and an alkatrienyl group. , Preferably 10-20. Also, p is preferably from 6 to 20. Further, q1 to q6 are each preferably 1 to 40, and the total of q1 to q6 is 6 to 10
0 is preferred. Also, r is preferably 1 to 60. Also, s1 ~
s3 is preferably 1 to 40, and the total of s1 to s3 is preferably 3 to 100, and s4 is preferably 1 to 40.

The content of the surfactant (C) in the positive photosensitive composition of the present invention is from 0.001 to 5%.
% By weight, more preferably 0.002 to 3% by weight, particularly preferably 0.005 to 1% by weight.

The phosphonium compound (D) contained in the positive photosensitive composition of the present invention is a compound in which four hydrogen atoms bonded to a phosphorus atom of an inorganic phosphonium compound are substituted with a substituent. In the present invention, in addition to the general compound represented by the following general formula (XI), the following general formula (X
Compounds represented by II) may also be targeted. These phosphonium compounds, in the positive photosensitive composition of the present invention, reduce the solubility of the novolak resin in an alkali developing solution, and increase the difference in solubility in an exposed portion and a non-exposed portion of the alkali developing solution, It has a function as a so-called dissolution inhibitor.

[0066]

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In the formulas (XI) and (XII), R ³³ , R ³⁴ , R
³⁵ , R ³⁶ , R ³⁷ , R ³⁸ , R ³⁹ , R ⁴⁰ , R ⁴¹ , and R ⁴² each independently represent a substituent which may further have a substituent, and R ^{33 to} R ³⁶ , R ³⁷ to R ^39, or may form a cyclic structure more are connected to each other within each R ³⁹ ~R ^42, W represents a divalent group, Xb ^- is a counter anion. ]

In the formulas (XI) and (XII), R ^{33 to} R ⁴²
Examples of the substituent include an alkyl group which may have a substituent, an alkenyl group which may have a substituent,
Alkynyl group which may have a substituent, cycloalkyl group which may have a substituent, alkoxy group which may have a substituent, aryl group which may have a substituent, An aryloxy group which may have a group, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a heterocyclic group which may have a substituent, And an amino group which may have a group.

Here, when R ^{33 to} R ⁴² are an alkyl group, an alkoxy group or an alkylthio group, the number of carbon atoms is usually 1 to
20, an alkenyl group and an alkynyl group usually have 2 to 15 carbon atoms, and a cycloalkyl group has usually 3 to 8 carbon atoms.
Examples of the naphthyl group include an aryloxy group such as a phenoxy group and a naphthyloxy group; examples of the arylthio group include a phenylthio group; and examples of the heterocyclic group include a furyl group and a thienyl group.

Further, these alkyl groups, alkenyl groups,
Examples of a substituent in an alkynyl group, a cycloalkyl group, an alkoxy group, an aryl group, an aryloxy group, an alkylthio group, an arylthio group, a heterocyclic group, an amino group, and the like include, for example, an alkyl group, an alkenyl group, an alkynyl group, and a cycloalkyl group. , Alkoxy group, alkoxycarbonyl group, acyl group, alkylthio group, aryl group, aryloxy group, arylthio group, sulfino group, sulfo group, phosphino group, phosphoryl group, amino group, nitro group, cyano group, hydroxy group, and halogen Atoms and the like. Incidentally, these substituents may further have a substituent.

In the formulas (XI) and (XII), 2 of W
Examples of the valent group include an alkylene group and a phenylene group. Examples of the counter anion of Xb ⁻ include, for example, Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ ⁻ , PF ₆ ⁻ , and S
inorganic acid anions such as inorganic boric acid such as bF ₆ ⁻ , AsF ₆ ⁻ and BF ₄ ⁻ and BCl ₄ ⁻ ; and methyl, ethyl, propyl, butyl, phenyl, methoxyphenyl,
Organic acid anions such as organic boric acid having an organic group such as naphthyl, fluorophenyl, difluorophenyl, pentafluorophenyl, thienyl and pyrrolyl can be mentioned. Among ^{them, Cl -, Br -, I} -, ClO 4
^- , PF _6- ^{and the} like are preferred.

In the present invention, specific examples of suitable phosphonium compounds are shown below. In the following specific examples, “P
"h" represents a phenyl group, and "Na" represents a naphthyl group.

[0073]

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[0074]

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In the above, as the phosphonium compound in the present invention, a compound in which R ^{33 to} R ⁴² are an alkyl group which may have a substituent or a phenyl group which may have a substituent. The compound represented by the above formula (XI), wherein R ^{33 to} R ³⁶ are an alkyl group which may have a substituent or a phenyl group which may have a substituent, is particularly preferable.

The content of the phosphonium compound of the component (D) in the positive photosensitive composition of the present invention is 0.0
It is preferably from 1 to 30% by weight, more preferably from 0.05 to 20% by weight, particularly preferably from 0.1 to 15% by weight.

The positive photosensitive composition of the present invention may contain another dissolution inhibitor in combination with the phosphonium compound of the component (D) as a dissolution inhibitor. For example, sulfonic acid esters, phosphoric acid esters, aromatic carboxylic acid esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines described in detail in JP-A-10-268512, JP-A No. 11-1 such as aromatic ethers
90903, an acid-color-forming dye having a lactone skeleton, an N, N-diarylamide skeleton, and a diarylmethylimino skeleton;
No. 076, lactone skeleton,
Base coloring dyes having a thiolactone skeleton or a sulfolactone skeleton can be exemplified. Among the surfactants of the component (C), nonionic surfactants also act as dissolution inhibitors, and those having an HLB of 8 or more are particularly preferable.

The positive photosensitive composition of the present invention may further comprise a photothermal conversion material of the component (A), a novolak resin of the component (B), or another binder resin, and an interface of the component (C). In addition to the activator and the phosphonium compound of component (D), or other dissolution inhibitors,
If necessary, an organic acid or an anhydride thereof having _a pKa of preferably 2 or more may be contained for the purpose of improving developability such as imparting under-developability.

Examples of the organic acid and its anhydride include those described in JP-A-60-88942 and JP-A-63-2760.
48, JP-A-2-96754 and the like, and specifically, glyceric acid, methylmalonic acid, dimethylmalonic acid, propylmalonic acid, succinic acid, malic acid, mesotartaric acid, Glutaric acid, β-methylglutaric acid, β, β-dimethylglutaric acid, β-ethylglutaric acid, β, β-diethylglutaric acid, β-propylglutaric acid, β, β-methylpropylglutaric acid, pimelic acid, suberin Acid, aliphatic saturated carboxylic acid such as sebacic acid, aliphatic unsaturated carboxylic acid such as maleic acid, fumaric acid, glutaconic acid, 1,1-cyclobutanedicarboxylic acid, 1,3-cyclobutanedicarboxylic acid, 1,1-cyclohexane Pentanedicarboxylic acid, 1,2-cyclopentanedicarboxylic acid, 1,1-cyclohexanedicarboxylic acid, 1,
Carbocyclic saturated carboxylic acids such as 2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 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,
Ascorbic acid, succinic anhydride, glutaric anhydride, maleic anhydride, cyclohexenedicarboxylic anhydride, cyclohexanedicarboxylic anhydride, phthalic anhydride and the like can be mentioned.

The content of the organic acid or its anhydride in the positive photosensitive composition of the present invention is preferably 0 to 30% by weight, more preferably 0 to 20% by weight, Particularly preferred is 10% by weight.

The positive photosensitive composition of the present invention may further contain, if necessary, for example, Victoria Pure Blue (42595) and Crystal Violet (4255).
5), crystal violet lactone, auramine O
(41000), Catillon Brilliant Flavin (Basic 13), Rhodamine 6 GCP (45160), Rhodamine B (45170), Safranin OK 70:10
0 (50240), Erioglaucine X (4208)
0), First Black HB (26150), No.
120 / Lionol Yellow (21090), Lionol Yellow GRO (21090), Shimla First Yellow 8GF (21105), Benzidine Yellow 4
T-564D (21095), Shimla Fast Red 4015 (12355), Lionol Red B440
1 (15850), Fast Gen Blue TGR-L
(74160), Lionol Blue SM (26150)
And a coloring agent such as a pigment or a dye.
Here, the numbers in parentheses described above refer to the color index (CI).

The content ratio of the colorant in the positive photosensitive composition of the present invention is preferably 0 to 50% by weight, more preferably 0.5 to 30% by weight, and more preferably 2 to 30% by weight.
Particularly preferred is 20% by weight.

The positive photosensitive composition of the present invention may be further cross-linked, if necessary, by post-heating after exposure and development to form a positive image with chemical resistance and printing durability. A cross-linking agent having an action of cross-linking the novolak resin may be contained for the purpose of imparting a novolak resin.Typically, the cross-linking agent is a methylol group as a functional group, which is obtained by alcohol condensation modification. Examples thereof include an amino compound having at least two acetoxymethyl groups, such as an alkoxymethyl group, and specifically, a melamine derivative, for example, methoxymethylated melamine [Mitsui Cytec Co., Ltd., Cymel 300 series (1) and the like],
Benzoguanamine derivatives [Methyl / ethyl mixed alkoxylated benzoguanamine resins (Mitsui Cytec Co., Ltd., Cymel 1100 series (2) etc.)], glycoluril derivatives [Tetramethylol glycoluril resins (Mitsui Cytec Co., Ltd., Cymel 1100 series (3) etc.)]
And urea resin derivatives and resole resins.

The content of the crosslinking agent in the positive photosensitive composition of the present invention is preferably 0 to 20% by weight, more preferably 0 to 10% by weight, and more preferably 0 to 5% by weight. It is particularly preferred.

In addition to the above components, the positive photosensitive composition of the present invention may further contain, for example, dyes, pigments, coatability improvers, adhesion improvers, sensitivity improvers, sensitizers, and developability improvers. And various additives commonly used in photosensitive compositions such as
% By weight, preferably 10% by weight or less.

In general, when the positive photosensitive composition does not contain a compound having sensitivity to light in the ultraviolet region, the sensitivity and the contrast between the image area and the non-image area tend to be poor. Accordingly, the positive photosensitive composition of the present invention does not include a compound having sensitivity to light in the ultraviolet region, such as an onium salt, a diazonium salt, and a compound containing a quinonediazide group, and is substantially free from light in the ultraviolet region. It is preferable that the compound has no sensitivity, since the effect of the present invention in terms of the sensitivity and the contrast between the image portion and the non-image portion can be more remarkably exhibited. Here, the term "substantially insensitive to light in the ultraviolet region" means that there is no substantially significant difference in solubility in an alkali developer before and after irradiation with light having a wavelength of 360 to 450 nm. Means that it has no image forming ability in a practical sense.

The above-mentioned positive photosensitive composition of the present invention is usually applied to the surface of a support as a coating solution prepared by dissolving or dispersing the above-mentioned components in an appropriate solvent, and then heated and dried to obtain a support. A positive-type photosensitive lithographic printing plate having a surface of the positive-type photosensitive composition layer formed on a surface thereof.

Here, the solvent is not particularly limited as long as it has a sufficient solubility in the components used and gives good coating properties. Examples thereof include methyl cellosolve and
Cellosolve solvents 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 solvents 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 solvents such as methyl 3-methoxypropionate, heptanol Hexanol, diacetone alcohol, alcohol solvents such as furfuryl alcohol, cyclohexanone, ketone solvents such as methyl amyl ketone,
Highly polar solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like, or a mixed solvent thereof, and further a mixture thereof with an aromatic hydrocarbon may be used. The usage ratio of the solvent is usually in the range of about 1 to 20 times by weight based on the total amount of the photosensitive composition.

As the coating method, conventionally known methods, for example, spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, curtain coating and the like can be used. The coating amount varies depending on the application, but is usually 0.3 to 7 μm as a dry film thickness.
m, preferably 0.5-5 μm, particularly preferably 1-3
μm range. 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.

The support is made of aluminum,
Metal plates such as zinc, copper, steel, aluminum, zinc, copper,
Metal plates plated or evaporated with iron, chromium, nickel, etc.
Examples include paper, paper coated with resin, paper to which metal foil such as aluminum is adhered, plastic film, plastic film subjected to hydrophilic treatment, and glass plate. Inside,
Preferable is an aluminum plate, which has been subjected to surface treatment such as graining treatment by electrolytic etching or brush polishing in a hydrochloric acid or nitric acid solution, anodizing treatment in a sulfuric acid solution, and if necessary, sealing treatment. Aluminum plates are more preferred. The surface roughness of the support is JIS B0
Average roughness R _a as defined in 601, usually 0.3-1.
0 μm, preferably about 0.4 to 0.8 μm.

In the method of forming a positive image according to the present invention, the positive photosensitive lithographic printing plate having the positive photosensitive composition layer on the surface of a support is image-exposed and then developed with an alkali developing solution. Forming an image.

Here, the light source for imagewise exposing the positive photosensitive composition layer is mainly a HeNe laser,
A laser light source such as an argon ion laser, a YAG laser, a HeCd laser, a semiconductor laser, and a ruby laser may be used. In particular, when an image is formed by absorbing light and generating heat, a wavelength range of 650 to 1,30 is used.
A light source that generates a near-infrared laser beam in the range of 0 nm is preferable, and examples thereof include a ruby laser, a YAG laser, a semiconductor laser, and a solid-state laser such as an LED. preferable. Usually, after scanning exposure by these light sources, an image is formed by developing with an alkali developing solution.

The laser light source normally scans the surface of the photosensitive composition layer as a high-intensity light beam (beam) condensed by a lens, and the sensitivity of the photosensitive composition layer according to the present invention responds to the scanning. The characteristic (mJ / cm ² ) may depend on the light intensity (mJ / s · cm ² ) of the received laser beam. Here, the light intensity of the laser beam is obtained by dividing the amount of energy per unit time (mJ / s) of the laser beam measured by the optical power meter by the irradiation area (cm ² ) of the laser beam on the surface of the photosensitive composition layer. 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 exhibiting a reciprocity law. .

In the present invention, the light intensity of the light source is
It is preferably at least 2.0 × 10 ⁶ mJ / s · cm ^2, more preferably at least 1.0 × 10 ⁷ mJ / s · cm ² . When the light intensity is in the above range, the sensitivity characteristics of the positive photosensitive composition layer in the present invention can be improved, and the scanning exposure time can be shortened, which is a great advantage practically.

Examples of the developing solution used for developing the positive photosensitive body obtained by imagewise exposing the positive photosensitive lithographic printing plate of the present invention include sodium silicate, potassium silicate, lithium silicate, ammonium silicate, sodium metasilicate, Potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, dibasic sodium phosphate, tertiary sodium phosphate,
Inorganic alkali salts such as ammonium diphosphate, tertiary ammonium phosphate, sodium borate, potassium borate and ammonium borate, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, monobutylamine, mono Ethanolamine,
An alkaline developer comprising an aqueous solution of about 0.1 to 5% by weight of an organic amine compound such as diethanolamine, triethanolamine, monoisopropanolamine and diisopropanolamine is used. Among them, alkali metal silicates such as sodium silicate and potassium silicate which are inorganic alkali salts are preferable. The developing solution may contain, if necessary, the same surfactants as nonionic surfactants, anionic surfactants and amphoteric surfactants as mentioned above as the component (C), and organic solvents such as alcohol. Can be added.

The development is usually carried out by immersion development, spray development, brush development, ultrasonic development, or the like.
It is carried out at a temperature of about 50 to about 50C, particularly preferably about 15 to 45C.

[0097]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

Examples 1 to 10 and Comparative Example 1 An aluminum plate (0.24 mm thick) was degreased in a 5% by weight aqueous solution of sodium hydroxide at 60 ° C. for 1 minute, and then 0.5 mol / mol In an aqueous solution of hydrochloric acid having a concentration of 1 liter, a temperature of 28 ° C., a current density of 60 A / dm ² , and a processing time
Electrolytic etching was performed under the condition of 0 second. Next, after a desmut treatment at 60 ° C. for 12 seconds in a 4% by weight aqueous sodium hydroxide solution, a 20% by weight sulfuric acid solution at a temperature of 20 ° C., a current density of 3.5 A / dm ² and a treatment time of 1 minute. For anodizing treatment. In addition, 2
Hot water sealing treatment was performed for 0 second to produce an aluminum plate for a lithographic printing plate support. Surface roughness meter (Kosaka Laboratory,
The average roughness Ra value of this plate according to “SE-3DH”) was 0.60 μm.

On the surface of the obtained aluminum plate support,
As the photothermal conversion material of the component (A), 4 parts by weight of the cyanine dye shown in the specific example (II-9), and as the novolak resin of the component (B), the mixing ratio of phenol: m-cresol: p-cresol is as follows. polycondensate novolak resin (M _W 9,000) consisting of 100 parts by weight of the mixed phenols and formaldehyde 50:30:20 molar ratio,
As a surfactant of the component (C), 4 parts by weight of a polyethylene oxide adduct of sorbite tetraoleate (“GO-4” manufactured by Nikko Chemicals Co., Ltd.), and as a dissolution inhibitor, a component (D) shown in Table 1 4 parts by weight of a phosphonium compound, 6 parts by weight of 1,2-cyclohexenedicarboxylic acid as an organic acid, 10 parts by weight of crystal violet lactone as a colorant, and methoxymethylated melamine as a cross-linking agent (“Cymer C-30 manufactured by Mitsui Cytec Co., Ltd.)
0 ") 1 part by weight and 10 parts by weight of an ester condensate of a novolak resin and 5-hydroxy-6-diacetylmethylidenehydrazino-naphthalenesulfonic acid were added to 720 parts by weight of methyl cellosolve and 180 parts by weight of ethyl cellosolve. A coating solution prepared by stirring at room temperature for 10 minutes was applied using a wire bar, dried at 80 ° C. for 3 minutes, and then heat-treated at 60 ° C. for 24 hours to obtain a coating amount of 2.5 g / A positive photosensitive lithographic printing plate having a m ² positive photosensitive composition layer was prepared.

For each of the obtained positive photosensitive lithographic printing plates, an exposure apparatus using a 830 nm semiconductor laser as a light source (trade setter 3244 manufactured by Creo Corporation) was used.
T "), image exposure of a halftone dot image of 200 lines, 1 to 99% with an exposure energy of 135 mJ / cm ² , and then an alkali developing solution (“ DP- ”manufactured by Fuji Photo Film Co., Ltd.)
In a lithographic printing plate in which a halftone image of 1 to 99% is reproduced by performing development processing at 28 ° C. using a 10-fold diluted solution of “4”), an exposed portion (non-image portion) and a non-exposed portion By measuring each reflection density before and after development in the portion (image portion) using a reflection densitometer (“RD-514” manufactured by Macbeth) and calculating the remaining film ratio based on the following formula, The development time [T ₁ (second)] at which the residual film ratio reaches 0%, and the development time [T
₂ (sec)], and [T ₂ / T ₁ ] value as the development allowance was calculated. The results are shown in Table 1.

Residual film ratio (%) = [(reflection density of exposed or unexposed area after development−reflection density of support surface) / (reflection density of plate surface before development−reflection density of support surface)] × 100

COMPARATIVE EXAMPLE 1 Except that no phosphonium compound (D) was used,
In the same manner as in Examples 1 to 10, positive photosensitive lithographic printing plates were prepared and evaluated, and the results are shown in Table 1.

[0103]

[Table 1]

[0104]

According to the present invention, a positive photosensitive composition comprising a photothermal conversion substance and an alkali-soluble resin,
Positive photosensitive composition having high sensitivity to light in the near-infrared region, excellent contrast between the image area and the non-image area, and thus having a wide range of development conditions, and a positive photosensitive lithographic printing plate And a positive image forming method using the same.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/00 503 G03F 7/00 503 7/023 511 7/023 511 H01L 21/027 H01L 21/30 502R F-term (Reference) 2H025 AA00 AA01 AB03 AB13 AB15 AB16 AC08 AD03 CB29 CC04 CC20 FA10 FA17 2H096 AA00 AA07 AA08 AA25 AA26 AA28 BA16 BA20 EA04 GA08 4J002 AE052 BG011 BH001 BH011 CC031 CC041EF05 012 EF05 CC021EF05 CC011 EH057 EL086 EN117 EN137 EU026 EU056 EU117 EU216 EV137 EV236 EV286 EV296 EV306 EV326 EW178 FD056 FD09 FD14 FD206 FD208 FD312 FD317 GP03

Claims (7)

[Claims] 1. The following components (A), (B) and (C)
A positive photosensitive composition comprising a component and component (D). (A) a photothermal conversion material that absorbs light from an image exposure light source and converts it into heat (B) novolak resin (C) surfactant (D) phosphonium compound 2. The photothermal conversion material of component (A) has a wavelength range of 6
The positive photosensitive composition according to claim 1, which is a light-absorbing dye having a near-infrared absorbing ability of 50 to 1,300 nm. 3. The positive photosensitive composition according to claim 2, wherein the light absorbing dye is a cyanine dye having a basic structure in which a heterocyclic ring is bonded via a polymethine chain. 4. The positive photosensitive composition according to claim 1, wherein the surfactant (C) is a nonionic surfactant. 5. The positive photosensitive composition according to claim 1, wherein the phosphonium compound as the component (D) is a compound having an alkyl group and / or a phenyl group as a substituent. 6. A positive photosensitive lithographic printing plate comprising a support and a layer of the positive photosensitive composition according to claim 1 formed thereon. 7. The positive image forming method according to claim 6, wherein the positive photosensitive lithographic printing plate according to claim 6 is scanned and exposed with a laser beam having a wavelength range of 650 to 1,300 nm, and then developed with an alkali developing solution. Method.