JP2001142202A - Positive photosensitive composition and positive photosensitive planographic printing plate - 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 the contrast between image and non-image areas and having wide development latitude and to obtain a positive photosensitive planographic printing plate. SOLUTION: The positive photosensitive composition contains a photothermal conversion material which absorbs light of a light source for imagewise exposure and converts it to heat and an alkali-soluble resin. The photothermal conversion material is a dye having a structure with heteroatoms bonded by way of a polymethine chain as the basic structure and having a substituent containing an ether bond which forms an oxonium cation or a thio-ether bond which forms a sulfonium cation by resonance in the molecule of the dye on the polymethine chain. A layer of the photosensitive composition is formed on the surface of a substrate to obtain the objective positive photosensitive planographic printing plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lithographic printing plate, a color proof for print proofing, a color filter resist for a liquid crystal display or a plasma display, a photoresist for an integrated circuit of a semiconductor device, a copper etching resist for a wiring board or gravure plate making, and the like. For positive photosensitive composition and positive photosensitive lithographic printing plate, which are highly sensitive to light in the near-infrared region used for lithographic printing plate, especially suitable for direct plate making by semiconductor laser or YAG laser etc. The present invention relates to a composition and a positive photosensitive lithographic printing plate.

[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, techniques using a combination of a chemically amplified photoresist and a long-wavelength light-absorbing dye have been found. For example, JP-A-6-43633 discloses a photosensitive material in which a specific squarylium-based dye is combined with a photoacid generator and a binder. Japanese Patent Application Laid-Open No. 7-271,029 discloses a method for preparing a lithographic printing plate by exposing a photosensitive composition layer containing an infrared absorbing dye, a latent Bronsted acid, a resole resin and a novolak resin to an image by a semiconductor laser or the like. Japanese Patent Application Laid-Open No. 9-43847 discloses a method using an s-triazine-based compound instead of the latent Bronsted acid.
A resist material which changes the crystallinity of the photosensitive material by heating by irradiation of infrared rays and a pattern forming method using the same,
Each is disclosed.

[0006] However, according to the study of the present inventors,
These conventional techniques have low sensitivity to light in the near-infrared region, and a small difference in solubility between the exposed part and the non-exposed part with respect to a developer. As a result, the non-image part is not sufficiently removed, In some cases, the residual film ratio in the portion was not sufficiently maintained, and therefore, there were practical disadvantages such as a narrow range of developing conditions.

On the other hand, the applicant of the present application has proposed a simple photochemical conversion material such as a photothermal conversion material composed of a near-infrared absorbing dye having a structure in which a heteroatom is bonded via a polymethine chain and an alkali-soluble resin. It has been found that a photosensitive composition capable of forming a positive image in which the above-mentioned disadvantages are eliminated can be obtained by using the system, and a patent application (JP-A-10-26851)
No. 2), and further improvement was under consideration.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned prior art. Therefore, the present invention has high sensitivity to light in the near-infrared region and has a high image quality. It is an object of the present invention to provide a positive photosensitive composition and a positive photosensitive lithographic printing plate which are excellent in contrast with a non-image portion and therefore have a wide range of developing conditions.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a dye having a basic structure in which a hetero atom is bonded via a polymethine chain, It has been found that a composition using a dye having a specific substituent as a photothermal conversion material together with an alkali-soluble resin can achieve the above object, and has completed the present invention.That is, the present invention provides light of an image exposure light source. A positive photosensitive composition containing a light-to-heat conversion material that absorbs and converts heat and an alkali-soluble resin, wherein the light-to-heat conversion material has a structure in which a heteroatom is bonded via a polymethine chain as a basic structure. A dye that resonates in the dye molecule on the polymethine chain to form an ether bond that generates an oxonium cation or a thioether bond that generates a sulfonium cation. Positive photosensitive composition containing a dye having an unsubstituted group, and a layer of photosensitive composition is formed on the surface of the support positive photosensitive lithographic printing plate,
Is the gist.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the positive photosensitive composition of the present invention, a photothermal conversion substance which absorbs light from an image exposure light source and converts it into heat is a compound which can convert the absorbed light into heat. In the present invention, a dye having a structure in which a heteroatom is bonded through a polymethine chain as a basic structure as the photothermal conversion substance, and on the polymethine chain, resonance occurs in a dye molecule to form oxonium. It contains a dye having a substituent containing an ether bond generating a cation or a thioether bond generating a sulfonium cation. Here, “resonating in the dye molecule” means, in other words, “resonating with the chromophore of the dye”, and the π electron of the chromophore in the dye molecule by the dye having the substituent. The system spreads, and the absorption peak is usually shifted to the longer wavelength side by 20 nm or more, and the absorption efficiency can be improved particularly in the near infrared region in the wavelength range of 700 to 1300 nm. These near-infrared absorbing dyes, while efficiently absorbing light in the above wavelength range,
It is a compound that hardly absorbs light in the ultraviolet region or is substantially insensitive to absorption, and has no function of denaturing the photosensitive composition by weak ultraviolet light contained in a white lamp.

[0011] In the present invention, these dyes via a polymethine (-CH =) _n chain, a nitrogen atom, an oxygen atom,
Or a structure in which a heteroatom such as a sulfur atom is bonded as a basic structure, and as the basic structure, typically, those heteroatoms form a heterocycle and a heterocycle is bonded via a polymethine chain. So-called cyanine dyes in a broad sense of the structure, specifically, for example, quinoline (so-called cyanine-based in a narrow sense), indole (so-called indocyanine-based), benzothiazole-based (so-called thiocyanine-based), pyrylium-based, Thiapyrylium-based, squarylium-based, croconium-based, azurenium-based, and so-called polymethine-based dyes having a structure in which an acyclic heteroatom is bonded through a polymethine chain, among which quinoline-based, indole-based, benzoin-based Preferred are cyanine dyes such as thiazole, pyrylium and thiapyrylium dyes, and polymethine dyes.

As the basic structure of the dye in the present invention, among the above-mentioned cyanine dyes, as the quinoline dye, those represented by the following general formulas (Ia), (Ib) or (Ic) are particularly preferable. .

[0013]

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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. Represents a phenyl group which may be substituted, and L ¹ represents, as a substituent, tri-, penta-, hepta-containing at least a substituent containing an ether bond generating an oxonium cation or a thioether bond generating a sulfonium cation by resonance in a dye molecule. , Shows a nona or undecamethine group, two substituents on the penta, hepta, nona, or undecamethine group are connected to each other to form a cycloalkene ring having 5 to 7 carbon atoms, a cycloalkenenone ring, a cycloalkenedione ring, or The cycloalkenethione ring may be formed, and the quinoline ring may have a substituent. In this case, two adjacent substituents may be substituted with each other. Linked to it may form a fused benzene ring. X _a ^- represents a counter anion. ]

Here, R in formulas (Ia), (Ib) and (Ic)¹
And R^TwoIs an alkyl group, the number of carbon atoms is usually 1 to
15, preferably 1 to 10, alkenyl group, alkynyl
When it is a group, it usually has 2 to 15, preferably 2 carbon atoms.
-10, and those substituents including a phenyl group
In general, carbon atoms having 1 to 15, preferably 1 to 10 carbon atoms
Lucoxy, phenoxy, hydroxy, or phenyl
And a group such as L ¹The ether bond in or
As a substituent other than the substituent containing a thioether bond,
Alkyl, amino, or halogen atom having the same carbon number
And the like. As the substituents on the quinoline ring,
Alkyl group having the same number of carbon atoms, alkoxy group having the same number of carbon atoms
And a toro group or a halogen atom.

As the basic structure of the dye in the present invention, among the above-mentioned cyanine dyes, indole and benzothiazole dyes are particularly represented by the following general formula (II):
Is preferably represented by

[0017]

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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, wherein L ² is a substituent,
A tri-, penta-, hepta-, nona- or undecamethine group having at least a substituent containing an ether bond generating an oxonium cation or a thioether bond generating a sulfonium cation in resonance in a dye molecule; Or two substituents on the undecamethine group are connected to each other to form a cycloalkene ring having 5 to 7 carbon atoms, a cycloalkenenone ring, a cycloalkenedione ring,
Or may form a cycloalkenethione ring, the fused benzene ring may have a substituent, in which case,
Two adjacent substituents may be linked to each other to form a fused benzene ring. X _a ^- represents a counter anion. ]

Here, when R ³ and R ⁴ in the formula (II) are an alkyl group, the number of carbon atoms is usually 1 to 15, preferably 1 to 10, and the number of carbon atoms when it is an alkenyl group or an alkynyl group. Is usually 2 to 15, preferably 2 to 10, and as a substituent thereof including a phenyl group, an alkoxy group having a carbon number of usually 1 to 15, preferably 1 to 10, a phenoxy group, a hydroxy group, or a phenyl group and the like, and the substituent other than the substituent containing the ether bond or a thioether bond in L ^2, supra alkyl group carbon atoms, an amino group, or a halogen atom and the like,
Examples of the substituent on the condensed benzene ring include an alkyl group having the same carbon number as described above, an alkoxy group having the same number of carbon atoms, a nitro group, and a halogen atom.

As the basic structure of the dye in the present invention, among the cyanine dyes, pyrylium-based and thiapyrylium-based dyes are particularly represented by the following general formula (III)
Those represented by a), (IIIb) or (IIIc) are preferred.

[0021]

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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, as a substituent, an ether bond or a sulfonium cation which resonates in the dye molecule to generate an oxonium cation. A mono-, tri-, penta- or heptamethine group having at least a substituent containing a resulting thioether bond, wherein the two substituents on the tri-, penta- or heptamethine group are linked together to form a cycloalkene ring having 5 to 7 carbon atoms; , A cycloalkeneone ring, a cycloalkenedione ring, or a cycloalkenethione ring, and the pyrylium ring and the thiapyrylium ring may have a substituent.
Two substituents may be linked to each other to form a fused benzene ring. X _a ^- represents a counter anion. ]

Here, in the formulas (IIIa), (IIIb) and (IIIc)
R^Five, R⁶, R⁷, And R⁸Is an alkyl group
Has usually 1 to 15, preferably 1 to 10
L ^ThreeSaid ether bond or thioether bond in
Substituents other than the substituent containing
A alkyl group, an amino group, or a halogen atom,
As a substituent on a pyrylium or thiapyrylium ring
And an aryl group such as a phenyl group.

Further, as the basic structure of the dye in the present invention, a polymethine-based dye is preferably represented by the following general formula (IV):
Is preferably represented by

[0025]

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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; L ⁴ represents a substituent;
A mono, tri, penta, or heptamethine group having at least a substituent containing an ether bond that produces an oxonium cation or a thioether bond that produces a sulfonium cation by resonance in the dye molecule; and the tri, penta, or heptamethine group The above two substituents may be connected 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 the quinone ring and the benzene ring may be substituted. It may have a group. X _a ^- represents a counter anion. ]

Here, the carbon number of the alkyl group of R ⁹ , R ¹⁰ , R ¹¹ and R ¹² in the formula (IV) is usually 1 to 15, preferably 1 to 10, and R ¹³ and R ¹⁴ are aryl. When it is a group, the number of carbon atoms is usually 6 to 20, preferably 6 to 15,
Specific examples of R ¹³ and R ¹⁴ include a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-furyl group, a 3-furyl group, a 2-thienyl group, and a 3-thienyl group. Examples of the substituent, ibid alkyl carbon atoms, ibid alkoxy group carbon atoms, a dialkylamino group, hydroxy group, or a halogen atom and the like, substitution of other substituents containing said ether bond or a thioether bond in L ⁴ Examples of the group include an alkyl group having the same number of carbon atoms, an amino group, and a halogen atom.Examples of the substituent on the quinone ring and the benzene 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, Or a halogen atom.

The compounds represented by the general formulas (Ia to c), (II) and (IIIa to
c) and the counter anion X in (IV) _a ^-As a concrete
Typically, for example, Cl^-, Br^-, I^-, ClO_Four ^-,
PF ₆ ^-, SbF₆ ^-, AsF₆ ^-And BF_Four ^-,
BCl_Four ^-Inorganic acid anions such as inorganic boric acid
Benzenesulfonic acid, toluenesulfonic acid, naphtha
Lensulfonic acid, acetic acid and methyl, ethyl, propyl
Butyl, phenyl, methoxyphenyl, naphthyl,
Fluorophenyl, difluorophenyl, pentafluor
With organic groups such as rophenyl, thienyl, pyrrolyl, etc.
Organic acid anions such as organic boronic acid can be mentioned.

The basic structures of the dyes in the present invention include quinoline compounds represented by the above-mentioned general formulas (Ia to c), indole-based compounds and benzothiazole-based compounds represented by the above-mentioned general formula (II), IIIa to c), a pyranium-based or thiapyrylium-based cyanine-based dye, and the general formula
Among the polymethine dyes represented by (IV), in the present invention, the indole or benzothiazole dyes represented by the general formula (II) are particularly preferred.

Also, L ¹ , L ² , L ³ ,
And a polymethine chain, including L ^4, the wavelength range 700 to
The heptamethine chain for 850 nm, the nonamethine chain for the wavelength range of 850 to 950 nm, and the undecamethine chain for the wavelength range of 950 to 1300 nm are preferable.

The dye in the present invention has a structure having a substituent containing an ether bond generating an oxonium cation or a thioether bond generating a sulfonium cation on the polymethine chain having the above basic structure by resonance in the dye molecule. It is essential that the substituent containing an ether bond or a thioether bond include those bonded by a chain ether bond or a chain thioether bond, and these are linked via another polymethine chain. It may be bound to the polymethine chain of the dye.

A chain ether bond on the polymethine chain which resonates in the dye molecule to produce an oxonium cation;
Alternatively, the resonance mechanism of a dye having a substituent bonded by a chain thioether bond that generates a sulfonium cation is, for example, a dye having a structure in which a nitrogen atom is bonded via a nonametin chain, Like that.

[0033]

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In the present invention, specific examples of the substituent containing a chain ether bond or a chain thioether bond include those represented by the following general formula (Va).

[0035]

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[In the formula (Va), W ¹ represents an oxygen atom or a sulfur atom, and R ^a represents an alkyl group which may have a substituent, an aryl group which may have a substituent, Or a heterocyclic group which may have a substituent. ]

Here, when ^Ra in the formula (Va) is an alkyl group, the number of carbon atoms is generally 1 to 15, preferably 1 to 1.
0, the number of carbon atoms when the aryl group is usually 6 to 20,
The number of carbon atoms when the heterocyclic ring is preferably 6 to 15, usually 2 to 15, preferably 2 to 10, and the substituents thereof include an alkyl group having 1 to 5 carbon atoms and 1 carbon atom.
An alkoxy group or a thioalkoxy group having 5 to 5 carbon atoms, an acyl group having 2 to 5 carbon atoms, an acyloxy group having 2 to 5 carbon atoms,
An alkoxycarbonyl group having 2 to 5 carbon atoms, a phenyl group, a naphthyl group, an isocyanate group or an isothiocyanate group, an oxo group or a thioxo group;
A heterocyclic group, a hydroxyl group, or a halogen atom.

In the compounds represented by the general formula (Va), R
Those in which ^a is a phenyl group or those in which R ^a is a heterocyclic group represented by the following general formula (Vb) are preferred.

[0039]

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[In the formula (Vb), W ¹ represents an oxygen atom or a sulfur atom, W ² represents an oxygen atom, a sulfur atom, a nitrogen atom, or a dialkylmethylene group, and W ¹ and W ² are the same. And the heterocyclic ring is a 4- to 6-membered ring, and may have a substituent.
Two substituents may be linked to each other to form a condensed ring. ]

Further, among those represented by the general formula (Vb), those represented by the following general formula (Vc), (Vd) or (Ve) are preferable, and represented by the following general formula (Vc) Are particularly preferred.

[0042]

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[In the formula (Vc), W ¹ represents an oxygen atom or a sulfur atom, and two W ^1s may be the same or different, and R ^b may have a substituent. Good alkyl group,
It represents an alkoxy group or thioalkoxy group which may have a substituent, an aryl group which may have a substituent, a heterocyclic group which may have a substituent, or a hydrogen atom. ]

[0044]

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[In the formula (Vd), W ¹ represents an oxygen atom or a sulfur atom, two W ^1s may be the same or different, and R ^c may have a substituent. Good alkyl group,
It represents an aryl group which may have a substituent, a heterocyclic group which may have a substituent, or a hydrogen atom. ]

[0046]

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[In the formula (Ve), W ¹ represents an oxygen atom or a sulfur atom, W ² represents an oxygen atom, a sulfur atom, a nitrogen atom, or a dialkylmethylene group, and W ¹ and W ² are the same. And the condensed ring represents an aromatic hydrocarbon ring. ]

Here, R ^b in formula (Vc) and R ^b in (Vd)
^{When c} is an alkyl group, the number of carbon atoms is usually 1-5, when it is an alkoxy group or a thioalkoxy group, the number of carbon atoms is usually 1-5, and when it is an aryl group, the number of carbon atoms is usually 6-6.
10, the number of carbon atoms when it is a heterocyclic group is usually 2 to 5, and the number of carbon atoms when W ² in the formula (Ve) is a dialkylmethylene group is usually 3 to 15.

Preferred examples of the substituents containing a chain ether bond or thioether bond on the polymethine chain are shown below.

[0050]

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In these dyes according to the present invention, a substituent containing a chain ether bond or a chain thioether bond on the polymethine chain is directly bonded via another chain ether bond or a chain thioether bond. Alternatively, a cross-linked structure bonded to the polymethine chain of the same or different dye via a divalent bonding group may be employed.

As the light-to-heat converting substance in the present invention, the above-mentioned substituent containing a chain ether bond which forms an oxonium cation or a chain thioether bond which forms a sulfonium cation on the polymethine chain by resonance in a dye molecule. Specific examples of the cyanine dye and the polymethine dye having a structure having the following are shown below. In the following specific examples, A
Is a chain ether bond or a chain substituent containing a thioether bond, X _a ^{- is, Cl -, Br -, I} -, Cl
It is a counter anion such as O ₄ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , p-toluenesulfonic acid, or 1-naphthalenesulfonic acid.

[0053]

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[0054]

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[0055]

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[0056]

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[0057]

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[0058]

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[0059]

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[0060]

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[0061]

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Further, in the present invention, on the polymethine chain having the basic structure, a substituent containing an ether bond generating an oxonium cation or a thioether bond generating a sulfonium cation upon resonance in a dye molecule includes:
One in which a cyclic ether bond or a cyclic thioether bond is formed by two substituents is exemplified.

A cyclic ether linkage on the polymethine chain which resonates in the dye molecule to produce an oxonium cation;
Or, the resonance mechanism of a dye having a substituent forming a cyclic thioether bond that generates a sulfonium cation is, for example, a dye having a structure in which a nitrogen atom is bonded via a nonametin chain as follows: Become.

[0064]

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In the present invention, examples of the substituent containing a cyclic ether bond or a cyclic thioether bond include those represented by the following general formula (VIa) incorporating a trimethine group.

[0066]

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[In the formula (VIa), W ³ represents an oxygen atom or a sulfur atom, and the heterocyclic ring containing W ³ is a 5- or 6-membered ring which may have a substituent. ]

Here, the substituent in the heterocyclic ring in the formula (VIa) is an alkyl group having 1 to 5 carbon atoms and a substituent having 2 carbon atoms.
And acyloxy groups having 5 to 5 carbon atoms, alkoxycarbonyl groups having 2 to 5 carbon atoms, phenyl groups, naphthyl groups, amino groups, heterocyclic groups having 2 to 5 carbon atoms, hydroxyl groups, and halogen atoms.

Among the compounds represented by the general formula (VIa),
Those represented by the following general formula (VIb) incorporating a trimethine group are preferred.

[0070]

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[In the formula (VIb), W ³ represents an oxygen atom or a sulfur atom, and the heterocyclic ring containing W ³ may have a substituent. ]

Here, examples of the substituent in the heterocyclic ring in the formula (VIb) include an alkyl group having 1 to 5 carbon atoms, a phenyl group, a naphthyl group, an amino group, and a halogen atom.

Preferred examples of the above-mentioned substituents containing a cyclic ether bond or a cyclic thioether bond on the polymethine chain are shown below.

[0074]

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As the photothermal conversion substance in the present invention, the above-mentioned polymethine chain has a substituent containing a cyclic ether bond which generates an oxonium cation or a cyclic thioether bond which generates a sulfonium cation by resonance in a dye molecule. Specific examples of the cyanine-based dye having the structure and the polymethine-based dye include, in the specific examples described as the dye having a substituent containing a chain ether bond or a chain thioether bond, (I-1) to (I-). 3), (II-1)-(II-3), (II-1
0) to (II-12), (III-2), (III-11), (III-13) to (III-
14), (III-20) and (IV-1) to (IV-6), a carbon atom having A as a substituent and a trimethine group containing two carbon atoms bonded thereto are substituted by the general formula (VIa ).

The basic structure is a structure in which a heteroatom is bonded via a polymethine chain, and an ether bond generating an oxonium cation or a thioether generating a sulfonium cation on the polymethine chain by resonance in a dye molecule. These dyes having a substituent containing a bond are described, for example, in N. Narayanan et al. "Near-Infrared Dyes for Hig
h Technology Applications "S. Daehne, URGenger, O.
The method described in S. Wolfbeis (Kluwer Academic Publishers), specifically, for example, a dye having a structure in which a heterocyclic ring is bonded via a polymethine chain having a chlorine atom as a substituent, and a corresponding alcohol Or a corresponding sodium salt compound of a thioalcohol, or the like.

In the positive photosensitive composition of the present invention, the content of the dye as a light-to-heat conversion material is 0.5 to 5%.
It is preferably 0% by weight, more preferably 1 to 40% by weight, and particularly preferably 2 to 30% by weight.

In the positive photosensitive composition of the present invention, as a photothermal conversion substance, an ether bond which generates an oxonium cation or a thioether bond which generates a sulfonium cation on the polymethine chain by resonance in a dye molecule. In addition to the above-described dye having a structure having a substituent, a dye having a structure having no substituent containing an ether bond and a thioether bond on a polymethine chain may be contained. Formulas (Ia to c), (I
L ¹ , L ² , L ³ in (I), (IIIa-c) and (IV)
And L ⁴ is a polymethine chain having no substituent containing an ether bond and a thioether bond, and
As the counter anion, the general formulas (Ia to c), (II), and (IIIa
To c) and those having the same inorganic acid anion or organic acid anion as mentioned in (IV).

In the positive photosensitive composition of the present invention, the content of the dye having a structure having no substituent containing an ether bond and a thioether bond on a polymethine chain is 0 to 20% by weight as a photothermal conversion substance. %, More preferably 0.1 to 15% by weight,
Particularly preferred is 10% by weight.

In the positive photosensitive composition of the present invention, as the alkali-soluble resin, a resin having a phenolic hydroxyl group, specifically, for example, a novolak resin, a resole resin, a polyvinylphenol resin, or an acrylic having a phenolic hydroxyl group And copolymers of acid derivatives.
Among them, a novolak resin, a resol resin, or a polyvinylphenol resin is preferable, and a novolak resin is particularly preferable.

The novolak 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, phloroglicinol, For example, aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and furfural (paraformaldehyde may be used in place of formaldehyde and paraaldehyde in place of acetaldehyde), or acetone, methyl ethyl ketone, and methyl isobutyl A resin polycondensed with at least one of ketones such as ketone, and in the present invention, phenols as phenols, o-cresol, m-cresol, p-cresol, 2,5-xylenol, 3,5-
Polycondensates of xylenol, resorcinol, pyrogallol and formaldehyde, acetaldehyde, propionaldehyde as aldehydes or ketones are preferred, and particularly m-cresol: p-cresol: 2
The mixing ratio of 5-xylenol: 3,5-xylenol: resorcinol is 40 to 100: 0 to 50: 0 in molar ratio.
A mixed phenol of 混合 20: 0 to 20: 0０〜20 or a mixed phenol of phenol: m-cresol: p-cresol in a molar ratio of 1-100: 0 to 70: 0-60; Polycondensates with formaldehyde are preferred. In addition, the positive photosensitive composition of the present invention may contain a solvent inhibitor described below. In that case, m-cresol: p-cresol: 2,5-xylenol: 3,
The mixing ratio of 5-xylenol: resorcinol is 70 to 100: 0 to 30: 0 to 20: 0 to 20: 0 in a molar ratio.
20 mixed phenols or a mixed ratio of phenol: m-cresol: p-cresol of 10 to 1 in molar ratio
A polycondensate of mixed phenols of 00: 0 to 60: 0 to 40 and formaldehyde is preferred.

[0082] The novolak resin has a weight average molecular weight in terms of polystyrene by gel permeation chromatography measurement (M _W) is preferably 1,000 to
5,000, more preferably 1,500 to 10,000
Is used.

The resole resin is a resin that has been polycondensed in the same manner except that an alkali catalyst is used instead of the acid catalyst in the polycondensation of the novolak resin. In the present invention, the same resin as the novolak resin is used. , phenols and mixtures composition and, preferably aldehydes or ketones, also is preferable in the same weight average molecular weight (M _W).

The polyvinyl phenol resin includes, for example, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene,
Trihydroxystyrene, tetrahydroxystyrene,
Hydroxystyrenes such as pentahydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl) propylene, and 2- (p-hydroxyphenyl) propylene (these include chlorine and 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, a resin having 1 carbon atom on a benzene ring is used.
Hydroxystyrene polymers which may have 4 to 4 alkyl groups as substituents are preferred, and unsubstituted benzene ring hydroxystyrene polymers are particularly preferred.

The polyvinyl phenol resin may be a partially hydrogenated resin or a resin in which some hydroxyl groups are protected by a tert-butoxycarbonyl group, a pyranyl group, a furyl group, or the like. The weight average molecular weight (M _W)
However, those having 1,000 to 100,000, particularly preferably 1,500 to 50,000 are used.

If the molecular weight of the novolak resin, resol resin and polyvinylphenol resin is smaller than the above range, a sufficient coating film as a resist cannot be obtained. If the molecular weight is larger than the above range, the solubility in an alkali developing solution is low. In other words, the removal of the non-image portion becomes insufficient, and it becomes difficult to obtain a resist pattern.

In the positive photosensitive composition of the present invention, the content of the alkali-soluble resin is preferably 1 to 98% by weight, more preferably 5 to 95% by weight, and more preferably 20 to 90% by weight. % Is particularly preferred.

The positive photosensitive composition of the present invention is used for the purpose of increasing the difference in solubility of an exposed part and an unexposed part in an alkali developing solution in addition to the photothermal conversion substance and the alkali-soluble resin. A dissolution inhibitor having a function of forming a hydrogen bond with the alkali-soluble resin to reduce the solubility of the resin, and hardly absorbing light in the near-infrared region and not being decomposed by light in the near-infrared region; It may be contained.

Examples of the dissolution inhibitor include sulfonic acid esters, phosphoric acid esters, aromatic carboxylic acid esters, aromatic disulfones, and carboxylic anhydrides described in detail in JP-A-10-268512 by the present applicant. Products, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc.
No. 3, the lactone skeleton, N,
Acid-color-forming dyes having an N-diarylamide skeleton and a diarylmethylimino skeleton;
No. 76, a base color-forming dye having a lactone skeleton, a thiolactone skeleton, and a sulfolactone skeleton, and a nonionic surfactant also described in detail in JP-A-10-341400. Can be mentioned. Among them, an acid coloring dye having a lactone skeleton is preferable.

The content of the dissolution inhibitor in the positive photosensitive composition of the present invention is preferably from 0 to 50% by weight, more preferably from 0 to 30% by weight, and more preferably from 0 to 2% by weight.
Particularly preferred is 0% by weight.

The positive photosensitive composition of the present invention may optionally contain, for example, Victoria Pure Blue (425
95), crystal violet (42555), crystal violet lactone, auramine O (4100
0), Kachiron Brilliant Flavin (Basic 1)
3), Rhodamine 6 GCP (45160), Rhodamine B (45170), Safranin OK 70: 100 (50
240), Erioglaucine X (42080), Fast Black HB (26150), No. 120 / Lionol Yellow (21090), Lionol Yellow G
RO (21090), Shimla First Yellow 8G
F (21105), Benzidine Yellow 4T-564D
(21095), Shimla Fast Red 4015
(12355), Lionol Red B4401 (158)
50), Fast Gen Blue TGR-L (7416
0) and a colorant such as a pigment or a dye such as Lionol Blue SM (26150). Here, the numbers in parentheses above indicate the color index (C.I.
I. ).

The content ratio of the colorant in the positive photosensitive composition of the present invention is preferably from 0 to 50% by weight, more preferably from 1 to 30% by weight, and more preferably from 2 to 20% by weight.
It is particularly preferred that the amount is by weight.

In the positive photosensitive composition of the present invention, in addition to the above components, for example, a coating improver, a developability improver, an adhesion improver, a sensitivity improver, a sensitizer and the like are usually used. 10% by weight or less, preferably 0.1 to 10% by weight of various additives
It may be contained in the range of 5% by weight.

The positive photosensitive composition of the present invention is usually applied to the surface of a support as a solution in which each of the above components is dissolved in an appropriate solvent, and then heated and dried to form a photosensitive composition on the support surface. This is a positive photosensitive lithographic printing plate having a composition layer formed thereon.

Here, the solvent is not particularly limited as long as it has a sufficient solubility for the components used and gives good coating properties, and 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, and N-methylpyrrolidone; acetic acid; a mixed solvent thereof; and a mixture of these with an aromatic hydrocarbon. 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, a conventionally known method, for example, spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, curtain coating or 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 plate 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 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. Aluminum plates are more preferred. The surface roughness of the support is JIS B0
Average roughness R _a as defined in 601, typically 0.3
The thickness is 1.0 μm, preferably about 0.4 to 0.8 μm.

The light source for imagewise exposing the positive photosensitive composition layer in the present invention includes mainly laser light sources such as HeNe laser, argon ion laser, YAG laser, HeCd laser, semiconductor laser, and ruby laser. In particular, when an image is formed by heat generated by absorbing light, a light source that generates a near-infrared laser beam of 700 to 1300 nm is preferable.
Ruby laser, YAG laser, semiconductor laser, L
A solid-state laser such as an ED can be used. In particular, a small-sized and long-life semiconductor laser or a YAG laser is preferable. Usually, after scanning and exposure with these light sources, an image is formed by developing with a developer.

The laser light source usually 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 is responsive thereto. 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 an 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 type photosensitive body obtained by imagewise exposing the positive type photosensitive lithographic printing plate of the present invention include sodium silicate, potassium silicate, lithium silicate, ammonium silicate, sodium metasilicate, and 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. Incidentally, a surfactant such as an anionic surfactant, a nonionic surfactant, or an amphoteric surfactant, or an organic solvent such as alcohol can be added to the developer as required.

The development is usually performed 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.

[0103]

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

Example 1 An aluminum plate (0.24 mm thick) was degreased in a 5% by weight aqueous sodium hydroxide solution at 60 ° C. for 1 minute, and then a 0.5 mol / liter aqueous hydrochloric acid solution was used. In, at a temperature of 28 ° C., a current density of 60 A / dm ² and a processing time of
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 an alkali-soluble resin, a mixing ratio of phenol: m-cresol: p-cresol in a molar ratio of 20:50:
A mixed phenol of 30, a novolac resin (M _W 7,000) consisting of a polycondensate of formaldehyde 100
3 parts by weight of a cyanine-based dye having a substituent containing a chain thioether bond as a light-to-heat conversion material,
And a coating solution prepared by stirring 10 parts by weight of crystal violet lactone and 900 parts by weight of methyl cellosolve at room temperature for 10 minutes using a wire bar,
After drying at a temperature of 55 ° C. for 16 minutes, a positive photosensitive lithographic printing plate having a positive photosensitive composition layer having a coating amount of 2.5 g / m ² was prepared. .
The dyes and the like used were completely dissolved by stirring for 10 minutes, and a positive photosensitive lithographic printing plate having a uniform positive photosensitive composition layer was obtained.

[0106]

Embedded image

With respect to the obtained positive photosensitive lithographic printing plate,
An exposure apparatus using a 830 nm semiconductor laser as a light source (“Trend Setter 3244, manufactured by Creo Corporation”).
T ") and 200 lines at various exposure energies, 1 to 1
A 99% halftone dot image is image-exposed, and then developed at 28 ° C. using an alkali developing solution (10-fold diluted solution of “DP-4” manufactured by Fuji Photo Film Co., Ltd.) to obtain a 1-99% halftone dot image. A printing plate reproducing the point image was produced. The sensitivity at that time was determined as the exposure amount at which a 3% halftone dot image was reproduced, and was 200 mJ / cm ² .

Example 2 The procedure of Example 1 was repeated, except that a cyanine dye having a substituent containing a chain thioether bond was used as the photothermal conversion material in the photosensitive composition layer. A lithographic printing plate was prepared and developed. The sensitivity at that time is 3
% Of the halftone dot image was reproduced.
It was 40 mJ / cm ² .

[0109]

Embedded image

Example 3 The same procedure as in Example 1 was repeated except that a cyanine dye having a substituent containing a cyclic ether bond was used as a photothermal conversion material in the photosensitive composition layer. A lithographic printing plate was prepared and developed. The sensitivity at that time was determined as an exposure amount at which a 3% halftone dot image was reproduced.
mJ / cm ² .

[0111]

Embedded image

Example 4 The procedure of Example 1 was repeated, except that a cyanine dye having a substituent having a cyclic ether bond was used as the photothermal conversion material in the photosensitive composition layer. A lithographic printing plate was prepared and developed. The sensitivity at that time was determined as an exposure amount at which a 3% halftone dot image was reproduced.
mJ / cm ² .

[0113]

Embedded image

Comparative Example 1 Example 1 was used as a photothermal conversion material in the photosensitive composition layer.
A positive photosensitive lithographic printing plate was prepared in the same manner as in Example 1 except that only the cyanine dye having no substituent containing a chain thioether bond in the cyanine dye used in Example 1 was used. Coating defects due to the crystal particles of the dye were observed in the conductive composition layer, and the lithographic printing plate was not practically usable.

Comparative Example 2 Example 2 was used as a photothermal conversion material in the photosensitive composition layer.
A positive photosensitive lithographic printing plate was prepared in the same manner as in Example 1 except that only the cyanine dye having no substituent containing a chain thioether bond in the cyanine dye used in Example 1 was used. Coating defects due to the crystal particles of the dye were observed in the conductive composition layer, and the lithographic printing plate was not practically usable.

[0116]

According to the present invention, a positive photosensitive composition having high sensitivity to light in the near-infrared region, excellent contrast between an image area and a non-image area, and having a wide range of development conditions. And a positive photosensitive lithographic printing plate can be provided. Furthermore, the positive photosensitive composition of the present invention has excellent solubility in a solvent, so that the photosensitive composition layer can be efficiently formed by coating on a support surface as a solution, and the productivity is improved. An excellent lithographic printing plate can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 61/06 C08L 61/06 101/00 101/00 C09B 23/00 C09B 23/00 LM G03F 7 / 00 503 G03F 7/00 503

Claims (12)

[Claims] 1. A positive photosensitive composition containing a photothermal conversion substance that absorbs light from an image exposure light source and converts it into heat, and an alkali-soluble resin, wherein the photothermal conversion substance is via a polymethine chain. A dye having a structure in which a heteroatom is bonded as a basic structure, wherein a substituent containing an ether bond that generates an oxonium cation or a thioether bond that generates a sulfonium cation on the polymethine chain by resonance in the dye molecule. A positive photosensitive composition comprising a dye having the formula: 2. The positive photosensitive composition according to claim 1, wherein the dye as the photothermal conversion substance is a cyanine dye having a basic structure in which a heterocyclic ring is bonded via a polymethine chain. 3. The positive photosensitive composition according to claim 2, wherein the cyanine dye as a photothermal conversion substance is a near-infrared absorbing dye represented by the following general formula (II). Embedded image [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 represent 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 phenyl group which may have a substituent; L ² represents a substituent in the dye molecule; An ether bond that resonates to produce an oxonium cation,
Or tri, penta, hepta, at least having a substituent containing a thioether bond to generate a sulfonium cation,
A nona or undecamethine group, and two substituents on the penta, hepta, nona, or undecamethine group are connected to each other to form a cycloalkene ring having 5 to 7 carbon atoms, a cycloalkeneone ring, a cycloalkenedione ring, or The alkenethione ring may be formed, and the condensed benzene ring may have a substituent. In this case, two adjacent substituents may be connected to each other to form a condensed benzene ring. X _a ^- represents a counter anion. ] 4. The dye as a light-to-heat converting substance, wherein the substituent containing an ether bond or a thioether bond on the polymethine chain is bonded by a chain ether bond or a chain thioether bond. The positive photosensitive composition according to any one of the above. 5. The positive photosensitive composition according to claim 4, wherein the substituent bonded by a chain ether bond or a chain thioether bond is represented by the following general formula (Va). Embedded image [In the formula (Va), W ¹ represents an oxygen atom or a sulfur atom;
^a represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or a heterocyclic group which may have a substituent. ] 6. The positive photosensitive composition according to claim 5, wherein the substituent bonded by a chain ether bond or a chain thioether bond is represented by the following general formula (Vb). Embedded image [In the formula (Vb), W ¹ represents an oxygen atom or a sulfur atom;
² represents an oxygen atom, a sulfur atom, a nitrogen atom, or a dialkylmethylene group; W ¹ and W ² may be the same or different; the heterocyclic ring is a 4- to 6-membered ring; And in this case, two adjacent substituents may be connected to each other to form a condensed ring. ] 7. The positive photosensitive composition according to claim 6, wherein the substituent bonded by a chain ether bond or a chain thioether bond is represented by the following general formula (Vc). Embedded image [In the formula (Vc), W ¹ represents an oxygen atom or a sulfur atom, and two W ^1s may be the same or different;
^b is an alkyl group which may have a substituent, an alkoxy group or a thioalkoxy group which may have a substituent, an aryl group which may have a substituent, A heterocyclic group or a hydrogen atom. ] 8. The dye as a photothermal conversion substance, wherein the substituent containing an ether bond or a thioether bond on the polymethine chain forms a cyclic ether bond or a cyclic thioether bond by two substituents.
4. The positive photosensitive composition according to any one of items 1 to 3. 9. The positive photosensitive material according to claim 8, wherein the two substituents forming a cyclic ether bond or a cyclic thioether bond are represented by the following general formula (VIa) incorporating a trimethine group. Composition. Embedded image [In the formula (VIa), W ³ represents an oxygen atom or a sulfur atom,
The heterocyclic ring containing W ³ may have a substituent 5 or 6
It is a member ring. ] 10. The positive photosensitive material according to claim 9, wherein the two substituents forming a cyclic ether bond or a cyclic thioether bond are represented by the following general formula (VIb) incorporating a trimethine group. Composition. Embedded image [In the formula (VIb), W ³ represents an oxygen atom or a sulfur atom,
The heterocyclic ring containing W ³ may have a substituent. ] 11. The positive photosensitive composition according to claim 1, wherein the alkali-soluble resin is a novolak resin. 12. A positive photosensitive lithographic printing plate comprising a support and a layer of the positive photosensitive composition according to claim 1 formed thereon.