JP2000066395A - Positive photosensitive composition, photosensitive planographic printing plate and positive image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure high sensitivity to near infrared laser, wide development latitude and no coating defects by incorporating a coloring material having an N,N-diaryliminium salt skeleton in its molecule. SOLUTION: A coloring material having at least one N,N-diarylirninium salt skeleton or N,N-diarylaminium skeleton in its molecule is incorporated as a near infrared light-heat conversion material. The coloring material absorbs light in the 650-1,300 nm wavelength range of a light source for exposure and generates heat. The near infrared light-heat conversion material has a high dissolution inhibiting effect by which solubility to an alkali developer is reduced by forming a hydrogen bond matrix by way of active hydrogen of hydroxyl groups or the like of an alkali-soluble resin. When the near infrared light-heat conversion material is irradiated with near infrared laser, it loses the high dissolution inhibiting effect because hydrogen bonds are relaxed or dissociated by the action of heat generated by the near infrared light-heat conversion material in the exposed part to facilitate the penetration of the alkali developer into a photosensitive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a photosensitive lithographic printing plate, a color proof for print proofing, a color filter for a liquid crystal display or a resist for a plasma press, a resist for an integrated circuit of a semiconductor device, a wiring plate or a gravure plate. The present invention relates to a positive photosensitive composition, a photosensitive lithographic printing plate, and a positive image forming method that can be used for a copper etching resist to be used.

[0002]

2. Description of the Related Art Positive photosensitive compositions include, for example, an orthoquinonediazide compound which becomes insoluble in alkali by generating indene carboxylic acid upon irradiation with light, an organic polymer substance having an ortho nitrocarbinol ester group, or an acid generating substance by light. There are known compositions containing a compound (acid generator) to be hydrolyzed and a compound or the like which is hydrolyzed by an acid to become alkali-soluble. In particular, with the advance of computer image processing technology, a photosensitive or heat-sensitive direct plate-making system that directly forms a resist image by laser light or a thermal head without outputting digital image information to a silver halide mask film has been developed. Attention has been paid.

In particular, a high-resolution laser-sensitive direct plate making system using a high-output semiconductor laser or a YAG laser is strongly desired to be realized from the viewpoints of miniaturization, environmental light during plate making work, and plate material cost. I have. In recent years, a technique of combining a chemically amplified photoresist with a long-wavelength light-absorbing dye has come to be seen. For example, JP-A-6-4
No. 3633 discloses a photosensitive material in which a specific squarium dye is combined with a photoacid generator, a binder and the like. Further, as a technique similar to this, there has been proposed a technique of preparing a lithographic printing plate by imagewise exposing a photosensitive layer containing an infrared absorbing dye, a latent Bronsted acid, a resol resin and a novolak resin to an image by a semiconductor laser or the like ( JP-A-7-20629) and a technique using an s-triazine compound in place of the latent Brönsted acid are also disclosed (JP-A-7-271029).

The above photosensitive materials contain a photoacid generator, a latent Bronsted acid or an s-triazine compound, and all of them are inferior in handleability under a white light. Further, these techniques involve a chemical change in image formation. On the other hand, JP-A-9-244233 discloses a combination of (A) a radical generator and a sensitizing dye A spectrally sensitized to two different wavelengths, and (B) a combination of a photoacid generator and a sensitizing dye B. combination,
Further, a lithographic printing plate material is described, which includes a photosensitive composition containing a radical polymerizable monomer and a compound that undergoes a decomposition reaction by an acid, and a photosensitive layer comprising the photosensitive composition on a hydrophilic support. . The image forming method of the publication is
(1) The acid generated from the photoacid generator by exposure to light in the absorption wavelength region of the sensitizing dye B causes an acid decomposition reaction of a compound which undergoes a decomposition reaction by the acid, and as a result, the exposed portion becomes hydrophilic. Is removed by liquid development to form a positive image,
(2) A wet image forming method in which batch exposure is performed in the absorption wavelength region of the sensitizing dye A to radically polymerize a radical polymerizable monomer to cure the film, and a dry image forming method similar thereto. That is, the image forming method involves two kinds of chemical reactions, an acid decomposition reaction and a radical polymerization.
Therefore, the photosensitive composition disclosed in Japanese Patent Application Laid-Open No. 9-244233 must contain a radical polymerizable monomer and a compound that undergoes a decomposition reaction by an acid.

[0005] The technique described in this publication involves, as an essential component, a photoacid generator which complicates the components of the photosensitive layer because it involves two types of chemical reactions. As described above, there is a drawback that work under a white light becomes difficult, as in the case of the above-mentioned technology, since it has absorption in the visible region.
By the way, JP-A-9-244233 discloses (A)
As a combination of a radical generator and a sensitizing dye A, that is, as a radical polymerization initiator of a radical polymerizable monomer, a combination of a cationic dye such as a cyanine dye or a polymethine dye and a radical generator is described. A combination compound of a diimmonium dye and a radical generator having the following structure is shown.

[0006]

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On the other hand, Japanese Patent Application Laid-Open No. 9-43847 discloses a resist material which changes the crystallinity of a photosensitive material by heating by irradiation of infrared rays, and a pattern forming method using the same.

[0008]

The present applicant has previously proposed a photosensitive composition for forming a positive image with a simple system of a photothermal conversion material and an alkali-soluble resin, which cannot be expected to undergo a photochemical change (see, for example, JP-A-10-268512). However, it is desired that these compositions have a wide development latitude due to a difference in sensitivity and solubility between exposed and unexposed portions.

A positive photosensitive composition containing an alkali-soluble resin and an o-quinonediazide group-containing compound as a photosensitizing component, which has been widely known, emits ultraviolet light that can be absorbed by the o-quinonediazide group-containing compound. By irradiation, the diazo moiety is decomposed and finally a carboxylic acid is generated, whereby the alkali solubility of the photosensitive composition is increased, that is, an image is formed by dissolving only the exposed part in an alkali developing solution. It is considered. Therefore, in this system, the components in the photosensitive composition are accompanied by a photochemical change.

On the other hand, the above-mentioned photosensitive composition proposed by the present applicant basically does not contain a component accompanied by a chemical change in image formation. Such an effect is mainly caused by a change other than the photochemical change. For example, when the photosensitive composition of the present invention once irradiated with light is heated at about 50 ° C. for 24 hours, the exposed portion increases immediately after the exposure. Can be inferred from the reversible phenomenon that the alkali solubility often returns to a state close to that before exposure, and furthermore, the glass transition temperature (or softening point) of the photosensitive composition itself used and the difficulty of the reversible phenomenon. As a result of examining the relationship with the degree, it was confirmed that the lower the transition temperature was, the more the reversible phenomenon was likely to occur.

The reason why the photosensitive composition forms such a positive image is not always clear, but the light energy absorbed by the photothermal conversion material is converted into heat,
The alkali-soluble resin in the heated part causes a change other than a chemical change such as a conformational change, and the alkali-solubility of the part increases,
It is believed that an image is formed by the alkali developer. A photosensitive composition capable of forming an image by a change other than such a chemical change is a relatively simple composition unlike a composition capable of forming an image due to a photochemical reaction,
Moreover, since it does not contain a compound that causes a photochemical change, it has an advantage that the handleability under a white light is good.

However, these photosensitive compositions whose image formation is caused by a change other than a chemical change are particularly sensitive to the difference in sensitivity and the difference in solubility between exposed and unexposed areas because of this special image formation mechanism. It is desired that the resulting development latitude is wide. An object of the present invention is to provide a positive photosensitive composition and a positive photosensitive lithographic printing plate having high sensitivity to near-infrared lasers, a wide development latitude, and no coating defects when a layer of the photosensitive composition is formed. Another object of the present invention is to provide a positive photosensitive composition and a positive photosensitive lithographic printing plate having high sensitivity to near-infrared laser.

Another object of the present invention is to provide a positive photosensitive composition and a positive photosensitive lithographic printing plate excellent in handleability under a white light. Furthermore, an object of the present invention is to provide a positive photosensitive composition and a positive photosensitive composition which do not require complicated processing steps such as exposure after development, have a relatively simple composition, and can form an image in a simple processing step. To provide a lithographic printing plate.

[0014]

[Means for solving the problem] This time, we have a certain N,
By containing a dye having at least one N-diaryliminium salt skeleton or at least one N, N-diarylaminium salt skeleton in a molecule, an exposed portion (non-image) of a positive-type photosensitive composition of this type at the time of plate making. Part), improved film-removing phenomena in the image part, and improved sensitivity. That is, the gist of the present invention is to provide a positive photosensitive composition containing a near-infrared light-to-heat conversion material and an alkali-soluble resin, wherein the near-infrared light-to-heat conversion material is an N, N-diaryliminium salt A positive photosensitive composition characterized by being a near-infrared absorbing dye having at least one skeleton or N, N-diarylaminium salt skeleton in the molecule.

[0015] Another gist is that, in a positive photosensitive composition containing an alkali-soluble resin and a near-infrared light-to-heat converting substance and having no radical polymerizability, the near-infrared light-to-heat converting substance is N,
The positive photosensitive composition is a near-infrared absorbing dye having at least one N-diaryliminium salt skeleton or N, N-diarylaminium salt skeleton in a molecule.

Another point is that a photosensitive composition containing an alkali-soluble resin and a near-infrared light-to-heat conversion material and capable of forming a positive image mainly by a change other than a chemical change, wherein the near-infrared light-to-heat conversion material is N-type , N-diaryliminium salt skeleton or near infrared absorbing dye having at least one N, N-diarylaminium salt skeleton in the molecule.

Another gist is that, in a positive photosensitive composition containing an alkali-soluble resin and a near-infrared light-to-heat conversion material and not containing a photoacid generator, the near-infrared light-to-heat conversion material is N, N
A near-infrared absorbing dye having at least one -diaryliminium salt skeleton or N, N-diarylaminium salt skeleton in a molecule;

Further, there is provided a photosensitive lithographic printing plate having a photosensitive layer comprising the above-mentioned positive photosensitive composition on a support. Further, the photosensitive lithographic printing plate was prepared for 650 to 1300 n.
m, and then developing with an alkali developer after exposure with a laser having a wavelength range of m.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, the photosensitive composition of the present invention does not contain a radical polymerizable monomer. This is related to the premise of the photosensitive composition of the present invention that substantially no chemical change is used for image formation. The radical polymerizable monomer is a compound having a function of polymerizing by the action of a radical, such as a compound containing an ethylenically unsaturated group.

The near-infrared light-to-heat conversion material used in the present invention is an N, N-diaryliminium salt skeleton or N, N-
A dye having at least one diarylaminium salt skeleton in a molecule, and having a wavelength range of 650 to 13 of an exposure light source.
It is a dye having a function of absorbing 00 nm light and generating heat (hereinafter, may be referred to as the present dye).

The details of the mechanism by which the near-infrared light-to-heat conversion substance having the N, N-diaryliminium salt skeleton or the N, N-diarylaminium salt skeleton exerts the effect of improving the positive image forming property are unknown. A N, N-diaryliminium base or N, N-diarylaminium base of a near-infrared light-to-heat conversion substance is a hydroxyl group of an alkali-soluble resin,
While forming a hydrogen bonding matrix via active hydrogen of a polar group such as an amino group or a carboxylic acid group, and having a high dissolution inhibiting effect of reducing the solubility of an alkali-soluble resin in an alkali developing solution, a near-infrared laser, especially a 650
The hydrogen bond is relaxed or dissociated by the action of heat generated by the near-infrared light-to-heat conversion material in the exposed portion during light irradiation of 〜1300 nm, thereby facilitating penetration of the photosensitive layer into the alkali developing solution. It is presumed that by having the effect of eliminating the high dissolution inhibiting effect, a high contrast between the laser exposed part and the unexposed part in the alkali developing solution is exhibited, resulting in high sensitivity and a wide development latitude. Is done.

The dye of the present invention has an N, N-diaryliminium salt skeleton or an N, N-diarylaminium salt skeleton, and has an absorption band in part or all of the near infrared region of 650 to 1300 nm. Any light absorbing dye can be used without particular limitation. The compound having the N, N-diaryliminium salt skeleton or the N, N-diarylaminium salt skeleton has higher positive image forming performance than other dyes, and furthermore has excellent solubility in various coating solvents. It can be added at a high compounding ratio, has excellent dissolution stability in the photosensitive layer, and has a characteristic that crystallization and other problems are unlikely to occur. In particular,
The following general formulas (α) and (β)

[0023]

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(In the formulas (α) and (β), R ³¹ and R ^{32 each} independently represent an aromatic hydrocarbon ring group having 6 to 20 carbon atoms which may have a substituent. The electronic bonds in the symbol represent resonance states with other electronic bonds.)
Having at least one diaryliminium salt skeleton or N, N-diarylaminium salt skeleton
100 dyes. Preferably, R ³¹ and R ^{32 of the} N, N-diaryliminium salt skeleton or the N, N-diarylaminium salt skeleton represented by the general formulas (α) and (β) are independently 1 to 3 nuclei, preferably 1 to 3 nuclei. To a dinuclear aromatic ring group which may have a substituent, and more preferably, R ³¹ and R ³² each independently represent a phenyl group or a naphthyl group which may have a substituent. , R ³¹ and R ³² each of which may have a substituent, the substituent of which may be an amino group which may have a substituent, an alkyl group which may have a substituent, Aryl group which may have a group, acyl group which may have a substituent, acyloxy group which may have a substituent, alkoxycarbonyl group which may have a substituent, substituent A carbonyloxy group which may have The dye is a nyl group, a bromine atom, a chlorine atom, an iodine atom, a fluorine atom, or a cyano group, and is preferably an amino group which may be substituted with an alkyl group having 1 to 20 carbon atoms. That is,
The aryl group contained in the N, N-diaryliminium salt skeleton or the N, N-diarylaminium salt skeleton is a phenyl group or a naphthyl group, and at least one of the aryl groups is substituted with an alkyl group as a substituent. A dye having a good amino group is preferable.

More preferably, the compound is a compound having one or two N, N-diaryliminium salt skeletons or N, N-diarylaminium salt skeletons, and having 3 or more benzene rings.
Or more, preferably 5 or more, and preferably 6 or less,
In particular, it is 5. Here, the benzene ring is a six-membered ring having a resonance structure, and also includes a skeleton that can become a benzene ring when the resonance structure is dissolved. For example, in general formula (I), there are five benzene rings, and in general formula (III), there are three. The molecular weight of the cationic portion of the dye of the present invention is 30.
It is about 0 to 1000. The compound may have a symmetrical structure or an asymmetrical structure, but the symmetrical structure tends to have higher sensitivity. More preferred dyes having an N, N-diaryliminium salt skeleton or N, N-diarylaminium salt skeleton include dyes represented by the following formulas (I) to (VI).

[0026]

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[0027]

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(In the formulas (I) to (VI), R ^{1 to} R ⁸ are each independently a hydrogen atom, an alkyl group which may have a substituent having 1 to 15 carbon atoms, a substituent having 6 to 15 carbon atoms. An aromatic hydrocarbon ring group which may have a group, or a heterocyclic group which may have a substituent having 4 to 15 carbon atoms, and R ^{9 to} R ^{16 each} independently represent a hydrogen atom or a carbon atom having 1 to ¹⁵ carbon atoms. An alkyl group optionally having 15 substituents, R ^{17 to} R ²⁴ are a hydrogen atom, an alkyl group optionally having 1 to 15 carbon atoms, an alkyl group having 6 to 15 carbon atoms,
An aromatic hydrocarbon ring group which may have a substituent, a heterocyclic group which may have a substituent having 4 to 15 carbon atoms, and a heterocyclic group which may have a substituent having 2 to 15 carbon atoms Good acyl group, alkoxycarbonyl group which may have a substituent having 2 to 15 carbon atoms, hydroxyl group, acyloxy group which may have a substituent having 2 to 15 carbon atoms, cyano group, chlorine atom, bromine An atom, an iodine atom or a fluorine atom, R ¹ and R ⁹ ,
R ² and R ^10, R ³ and R ^11, R ⁴ and R ^12, R ⁵ and R ^13, R
⁶ and R ¹⁴ , R ⁷ and R ¹⁵ , and R ⁸ and R ¹⁶ may be bonded directly or via at least one of an oxygen atom, a sulfur atom and an amino group to form a cyclic structure,
X ^- and Y ^- is represents a counter anion, respectively. The electronic bond (...) in the formulas (I), (III), and (V) indicates a resonance state with other electronic bonds. In particular, considering the distribution of electrons due to resonance, the following (I '), (II'), (III '), (IV'), (V ')
Or (VI ') is preferable.

[0029]

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[0030]

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(In the formulas (I ') to (VI'), R¹~ R
^{twenty four}Is the same as defined in the above formulas (I) to (VI).¹ ~
R¹⁶Independently has a hydrogen atom, a substituent having 1 to 10 carbon atoms
Alkyl group which may be substituted,
Phenyl or naphthyl which may have a substituent.
R¹⁷~ R^{twenty four}Are independently a hydrogen atom, a group having 1 to 10 carbon atoms.
Alkyl group which may have a substituent, having 1 to 10 carbon atoms
Optionally substituted alkoxy groups, hydroxyl groups, carbon
An acyl group optionally having 2 to 10 substituents,
A hydrogen atom, a bromine atom, a chlorine atom or an iodine atom;¹ 
~ R^{twenty four}Of each group which may have a substituent represented by
Is an alkyl group, an alkoxy group, a hydroxyl group, an amino group
Group, bromine group, chlorine group, fluorine group, iodine group,
X^-, Y^-Is Cl^-, Br^-, I^-, ClO_Four ^-, BF
_Four ^-, PF₆ ^-Such as inorganic acid anions, benzene sulfone
Acid, p-toluenesulfonic acid, naphthalenesulfonic acid,
Acetic acid, an organic acid such as an organic boric acid represented by the following general formula (L)
A dye that is an anion.

[0032]

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(Wherein, R ^{Q1 to} R ^Q4 each represent a hydrogen atom,
An alkyl group having 1 to 15 carbon atoms, an aromatic hydrocarbon ring group having 6 to 15 carbon atoms which may have a substituent, and a heterocyclic group having 4 to 15 carbon atoms which may have a substituent. Express. More specifically, R ^{Q1 to} R ^Q4 are each -CH ₃ ,-
_{C 2 H 5, -C 3 H} 7, -C 4 H 9, -C 4 H 9 -t,

[0034]

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And the like. Incidentally, the counter anion of the dye of the present invention may include those having a radical generating ability, but the photosensitive composition of the present invention does not contain a radical polymerizable monomer and has no radical polymerizability. Also need not have radical generating ability. Specific examples having a preferred N, N-diaryliminium salt skeleton or N, N-diarylaminium salt skeleton according to the present invention will be described below. The N, N-diaryliminium salt skeleton or N, N- The dye having a diarylaminium salt skeleton is not limited by these specific examples.

[0036]

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[0037]

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Where XA^-, YA^-Is Cl^-, Br^-,
I^-, ClO_Four ^-, BF_Four ^-, PF ₆ ^-, Benzenesul
Honic acid, p-toluenesulfonic acid, naphthalene sulfone
Acid or

[0039]

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Wherein R ⁴¹ and R ⁴² are respectively -H,-
_{CH 3, -C 2 H 5,} -C 3 H 7 -n, -C 4 H 9 -n
And WX, WV, WY and WZ represent

[0041]

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Represents the following. The above N, N-diarylimymi
Skeleton or N, N-diarylaminium salt skeleton
Of the general formulas (I ′) to (VI ′) having at least one
Among the infrared light-to-heat conversion materials, those having the structures of (I ′) to (IV ′)
Is easy to manufacture and has a wavelength of about 800 to 1300 nm
Is preferred because of its high sensitivity to irradiation light. In particular, R¹ ~ R
⁸ Is independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms
R ⁹ ~ R¹⁶Is a hydrogen atom or an alkyl having 1 to 6 carbon atoms
Group, especially a hydrogen atom, R ¹⁷~ R²⁰Is a hydrogen atom
Preferably. Furthermore, in terms of sensitivity, in particular,
Dyes having the structure (I ') or (II') are preferred.

The dye having an N, N-diaryliminium salt skeleton or an N, N-diarylaminium salt skeleton according to the present invention is disclosed in US Pat. No. 3,251,881, and US Pat.
5871, U.S. Pat. No. 3,484,467, JP-A-5-247.
437, JP-A-61-69991, JP-A-1-3169
No. 3, JP-B-7-51555 and the like, and can be synthesized by, for example, the following reaction formulas (1) to (1).
It is synthesized from the corresponding amine and halogenated nitrobenzene as represented by (4).

[0044]

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The dye having the N, N-diaryliminium salt skeleton or the N, N-diarylaminium salt skeleton may contain two or more different dyes in combination. The compounding ratio of the dye having the N, N-diaryliminium salt skeleton or the N, N-diarylaminium salt skeleton is 0.1 to 50 with respect to the solid content of the entire photosensitive layer composition.
%, Preferably 0.5 to 30% by weight, more preferably 0.5 to 20% by weight. If the content is extremely low, the sensitivity is lowered. If the content is extremely high, a residue of the photosensitive layer is liable to be generated in an exposed portion of the photosensitive layer during development, which may cause a problem.

Next, the alkali-soluble resin used in the present invention will be described. Any known alkali-soluble resin can be used. Specifically, it is an alkali-soluble organic polymer having a phenolic hydroxyl group, and has a polystyrene equivalent weight average determined by gel permeation chromatography (hereinafter abbreviated as GPC). Molecular weight (hereinafter, weight average molecular weight by GPC measurement is abbreviated as Mw)
Is usually 1000 to 100,000. More specifically, a novolak resin, a resole resin, a polyvinyl phenol resin, a copolymer of an acrylic acid derivative having a phenolic hydroxyl group, and the like can be mentioned. Of these, a novolak resin, a resole resin, or a polyvinyl phenol resin is preferable. Particularly preferred is a novolak resin.

As the novolak resin, phenol, m
-Cresol, o-cresol, p-cresol, 2,
5-xylenol, 3,5-xylenol, resorcinol, pyrogallol, bisphenol, bisphenol-
A, at least one kind of aromatic hydrocarbons such as trisphenol, o-ethylphenol, m-ethylphenol, p-ethylphenol, propylphenol, n-butylphenol, t-butylphenol, 1-naphthol and 2-naphthol; Polycondensation with aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde and furfural and at least one aldehyde or ketone selected from ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone under an acidic catalyst Is mentioned.

Instead of formaldehyde and acetaldehyde, paraformaldehyde and paraaldehyde, respectively, may be used. Novolak resin weight average molecular weight in terms of polystyrene determined by gel permeation chromatography (hereinafter abbreviated as GPC) measurement (hereinafter, weight average molecular weight measured by GPC is abbreviated as Mw) M
The w is preferably from 1,000 to 50,000, particularly preferably from 1,500 to 10,000.

The aromatic hydrocarbons of the novolak resin are more preferably pyrogallol, phenol, o-
Cresol, m-cresol, p-cresol, 2,5
-Xylenol, and a novolak resin obtained by polycondensing at least one phenol selected from 3,5-xylenol and resorcin with at least one aldehyde selected from formaldehyde, acetaldehyde, propionaldehyde and the like.

Among them, the mixing ratio of m-cresol: p-cresol: 2,5-xylenol: 3,5-xylenol: resorcin was 40 to 100: 0 to 5 in molar ratio.
Phenols of 0: 0 to 20: 0 to 20: 0 to 20 or phenols and aldehydes having a molar ratio of phenol: m-cresol: p-cresol of 1 to 100: 0 to 70: 0 to 60 Novolak resins which are polycondensates with the compounds are preferred. Of the aldehydes, formaldehyde is particularly preferred. Incidentally, the photosensitive composition of the present invention,
It may further contain a solvent inhibitor, in which case m-cresol: p-cresol: 2,5-xylenol:
The mixing ratio of 3,5-xylenol: resorcinol in a molar ratio of 70 to 100: 0 to 30: 0 to 20: 0 to 20 or a mixing ratio of phenol: m-cresol: p-cresol in a molar ratio 10 to 100: 0 to 6
Novolak resins which are polycondensates of phenols and aldehydes at 0: 0 to 40 are preferred.

As the polyvinyl phenol resin, o-
Hydroxystyrenes such as hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (o-hydroxyphenyl) propylene, 2- (m-hydroxyphenyl) propylene, and 2- (p-hydroxyphenyl) propylene; Two or more polymers are mentioned. Hydroxystyrenes may have a halogen such as chlorine, bromine, iodine or fluorine or a substituent such as a C ₁ -C ₄ alkyl substituent on the aromatic ring. or include better polyvinyl phenol which may have an alkyl substituent of C ₁ -C _4.

The polyvinylphenol resin is usually obtained by polymerizing hydroxystyrenes which may have a substituent alone or two or more in the presence of a radical polymerization initiator or a cationic polymerization initiator. Such a polyvinyl phenol resin may be partially hydrogenated.

The polyvinyl phenol resin is more preferably a polyvinyl phenol which may have an alkyl substituent having ₁ to ₄ carbon atoms on the aromatic ring, and unsubstituted polyvinyl phenol is particularly preferred. If the Mw of the novolak resin or the polyvinyl phenol resin is smaller than the above range, a sufficient coating film cannot be obtained. If the Mw is larger than this range, the solubility of the unexposed portion in the alkali developing solution becomes small, and a pattern is obtained. Tend not to be.

The resol resin can be obtained in the same manner as in the synthesis of the novolak resin except that an alkali catalyst is used instead of using an acid catalyst, and a resin having the same preferable molecular weight and polycondensation monomer composition as the novolak resin is preferable. The compounding ratio of the alkali-soluble resin is 1 to 98% by weight, preferably 5 to 98% by weight based on the total solid content in the photosensitive composition.
It is preferably from 95 to 95% by weight, more preferably from 10 to 90% by weight.

The positive photosensitive composition of the present invention comprises an alkali-soluble resin and at least one N, N-diaryliminium salt skeleton or N, N-diarylaminium salt skeleton.
The dye in the molecule is an essential component, does not contain a radical polymerizable monomer, and dissolves the positive photosensitive composition in an alkali developing solution by a change presumed to be the conformational change of the alkali-soluble resin due to heat as described above. Other ingredients may be included as long as the sex can change. However, as described above, since the photochemical reaction is not involved in the mechanism of image formation and the handleability under a white light is excellent, the positive photosensitive composition of the present invention containing the above two components as essential components The product also satisfies the following requirements.

(1) The photosensitive composition is capable of forming a positive image mainly due to a change other than a chemical change. (2) The photosensitive composition does not have radical polymerizability. (3) The photosensitive composition does not contain a photoacid generator. The above (1) is due to the fact that components that may cause a change in chemical bond due to light irradiation for forming a positive image are not included. Further, as described above, it is presumed that reversible development may be observed in the alkali solubility of the exposed part by heating the photosensitive composition once irradiated with light under mild conditions of about 50 ° C. .

In the above (2), “having no radical polymerizability” means, for example, that a radical polymerizable monomer such as an addition-polymerizable ethylenic compound and the photosensitive composition of the present invention coexist. This means that even when the photosensitive composition of the present invention is irradiated with near-infrared light to which the photosensitive composition is exposed, the addition-polymerizable ethylene compound is not cured by photopolymerization. Further, the absence of the photoacid generator of the above (3) is due to the fact that the image forming mechanism is different from that of the positive photosensitive composition containing a resin whose alkali solubility is increased by the action of an acid, Onium salt compounds such as halomethyltriazine compounds, diphenyliodonium salts, triphenylsulfonium salts, etc .; disulfomethane compounds, disulfodiazomethane compounds, etc.
It means that it does not contain a compound that generates an acid upon irradiation with light having a wavelength of 450 nm.

The positive photosensitive composition of the present invention may contain, if necessary, a near infrared absorbing dye having an N, N-diaryliminium salt skeleton or an N, N-diarylaminium salt skeleton of the present invention. An organic or inorganic pigment, an organic dye, which generates heat by light irradiation in a wavelength range of 650 to 1300 nm;
Metals and the like can be used in combination.

Specifically, for example, carbon black,
Graphite; metals such as titanium and chromium; metal oxides such as titanium oxide, tin oxide, zinc oxide, vanadium oxide and tungsten oxide; metal carbides such as titanium carbide; metal borides; described in JP-A-4-322219. Inorganic black pigments, azo black pigments, black or green organic pigments such as "Lionol Green 2YS" and "Green Pigment 7", and further JP-A-2-2074, JP-A-2075,
2076; JP-A-3-97590;
And organic dyes described in JP-A Nos. 63185, 26593, and 97589. The compounding ratio of the near-infrared light-to-heat conversion material having no diarylimino salt is 0 to 20% by weight, preferably 0.1 to 15% by weight, more preferably 1 to 10% by weight of the total solids of the photosensitive composition. %.

Further, in the photosensitive layer, if necessary, a coloring material other than the light-to-heat conversion substance can be contained for the purpose of imparting a visible image. As the coloring material, a pigment or a dye is used. More specifically, for example, Victoria Pure Blue (42595), crystal violet, 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 Fast Yellow 8GF (21105), Benzidine Yellow 4T-564D (21095), Shimla Fast Red 4015 (12355), Lionol Red B44
01 (15850), Fast Gen Blue TGR-L
(74160), Lionol Blue SM (26150)
And the like. The numbers in parentheses above indicate the color index (CI).

When the coloring material is contained, its compounding ratio is from 0 to 50% by weight, preferably from 1 to 30% by weight, based on the total solid content of the photosensitive layer composition. Further, the positive photosensitive composition of the present invention preferably contains a dissolution inhibitor for the purpose of further increasing the difference in solubility between the exposed part and the unexposed part. A dissolution inhibitor is a compound that substantially increases the difference in solubility by reducing the solubility of an unexposed portion of the positive photosensitive composition of the present invention in an alkali developer,
It is presumed that this forms a hydrogen bond with the alkali-soluble organic polymer substance, and has a function of reducing the solubility of the alkali-soluble organic polymer substance. Among them, a certain dissolution inhibitor having substantially no absorption by near-infrared light, that is, having an absorption efficiency of 1% or less of near-infrared light, and not being photolyzed by near-infrared light can be contained. .

The dissolution inhibitors used in the present invention include:
Japanese Patent Application No. 9-205789 describes acid anhydrides, sulfonic esters, phosphoric esters, aromatic carboxylic esters, aromatic ketones, aromatic aldehydes, aromatic amines,
Aromatic ethers, nonionic surfactants described in Japanese Patent Application No. 9-301915, fluorinated surfactants, Japanese Patent Application No. 9-2930
No. 91880 No. 9-3019
No. 15 base color-forming dyes.
The compounding ratio of these dissolution inhibitors is 0 to 50% by weight, preferably 0 to 30% by weight, and more preferably 0 to 20% by weight, based on the total solid content of the photosensitive composition. However,
Since the photosensitive composition of the present invention has good handleability under a white lamp, it has no component sensitive to UV light,
Accordingly, since the photosensitive composition is not exposed to ultraviolet light (hereinafter sometimes abbreviated as UV light) and has a property that the exposed portion is not substantially alkali-soluble by UV light irradiation, It is necessary to select a component that is not sensitive to UV light. It should be noted that the photosensitive composition does not have UV sensitivity when it is referred to as UV light,
The exposed portion has the property of not being substantially alkali-soluble even when irradiated with light in the region of 50 nm, that is, it means that there is no significant difference in solubility in an alkali developing solution.

More specifically, a white fluorescent lamp (36 W white fluorescent lamp manufactured by Mitsubishi Electric Corporation, NEOLMI Super FLR40S-
W / M / 36), it is preferable that the solubility of the positive photosensitive composition (photosensitive layer of the positive photoreceptor) does not change even when left for 10 hours under light irradiation of light intensity of 400 lux, It is preferable to use a dissolution inhibitor capable of achieving such properties as appropriate. The positive photosensitive composition used in the present invention is usually used by dissolving each of the above components in an appropriate solvent. The solvent is not particularly limited as long as it has a sufficient solubility for the components used and gives good coating properties, but cellosolve solvents such as methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, and ethyl cellosolve acetate. Propylene glycol solvents such as 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, and dipropylene glycol dimethyl ether; butyl acetate; Amyl acetate, ethyl butyrate, butyl butyrate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxy Ester solvents such as tylate, ethyl acetoacetate, methyl lactate, ethyl lactate, and methyl 2-methoxypropionate; alcohol solvents such as heptanol, hexanol, diacetone alcohol, and furfuryl alcohol; ketone solvents such as cyclohexanone and methyl amyl ketone Solvents, dimethylformamide, dimethylacetamide, highly polar solvents such as N-methylpyrrolidone, or a mixed solvent thereof,
Further, those obtained by adding an aromatic hydrocarbon to these are also exemplified. 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.

The positive-working photosensitive composition of the present invention may contain various additives, for example, a coating improver, a development improver, an adhesion improver, a sensitivity improver, a sensitizing agent, as long as the properties are not impaired. It is also possible to contain agents and the like. The photosensitive composition of the present invention can be advantageously used as a photosensitive lithographic printing plate by coating on a support. As a coating method used when the photosensitive layer is provided on the support surface, 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 may be used. Is possible. As drying conditions, for example, 60 to 170 ° C., 5 seconds to 10 minutes, preferably 70 to 1
50 ° C., 10 seconds to 5 minutes are employed.

The thickness of the photosensitive layer is usually 0.3 to 7 μm,
Preferably 0.5-5 μm, more preferably 1.0-3
μm. As a support on which a photosensitive layer using the photosensitive composition used in the present invention is provided, aluminum, zinc,
Metal plates such as copper and steel, and metal plates, paper, plastic films and glass plates plated or deposited with chromium, zinc, copper, nickel, aluminum, iron, etc., paper coated with resin, metal foil such as aluminum And a sheet such as a plastic film subjected to a hydrophilic treatment. As the support for the photosensitive lithographic printing plate, 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 solvent, and if necessary, sealing treatment, etc. It is more preferable to use a coated aluminum plate.

The roughness of the support surface is generally indicated by the value of the surface roughness Ra. This can be measured using a surface roughness meter. The support used in the present invention has an average roughness Ra of 0.3 to 1.
0 μm aluminum plate is preferable,
0.8 μm is more preferable. The support can be used after further performing a surface treatment with an organic acid compound, if necessary.

As a light source for imagewise exposing the positive photosensitive composition of the present invention, a light source such as a near-infrared laser having a wavelength of 650 to 1300 nm is generated particularly when absorbing light and forming an image by generated heat. Light source, such as a ruby laser, a YAG laser, a semiconductor laser, and an LE
D, other solid-state lasers, etc., and particularly a small-sized and long-life semiconductor laser or a YAG laser is preferable. With these laser light sources, usually, after scanning exposure, development can be performed with a developer to obtain an image.

The laser light source normally scans the surface of the photosensitive material as a high-intensity light beam (beam) condensed by a lens. The sensitivity characteristic of the positive type lithographic printing plate of the present invention (mJ / cm ² ) may depend on the light intensity (mJ / s · cm ² ) of the laser beam received on the photosensitive material surface. Here, the light intensity of the laser beam (mJ
/ S · cm ² ) is the amount of energy (mJ / s) of the laser beam on the plate surface per unit time measured with an optical power meter, and the beam diameter (irradiated area; cm ² ) on the surface of the photosensitive material is measured. It can be obtained by dividing the amount of energy per unit time by the irradiation area. The irradiation area of the laser beam is usually defined as the area of the portion exceeding 1 / e ² intensity of the laser peak intensity, but it can be simply measured by exposing a photosensitive material exhibiting a reciprocity law.

The light intensity of the light source used in the present invention is preferably 2.0 × 10 ⁶ mJ / s · cm ² or more, and 1.0 × 10 ⁷ mJ / s · cm ² or more. Is more preferred. When the light intensity is within the above range, the sensitivity characteristics of the positive photosensitive composition of the present invention are improved, and the scanning exposure time can be shortened.

The photosensitive composition and the photosensitive lithographic printing plate of the present invention can form a positive image by developing after exposure. As the developer used for developing the photosensitive composition of the present invention, an alkali developer mainly containing an aqueous alkali solution is particularly preferred. Examples of the alkali developer include, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium metasilicate, potassium metasilicate,
An aqueous solution of an alkali metal salt such as dibasic sodium phosphate and tribasic sodium phosphate is exemplified. The concentration of the alkali metal salt is preferably from 0.1 to 20% by weight. If necessary, an anionic surfactant, a nonionic surfactant, an amphoteric surfactant or an organic solvent such as an alcohol can be added to the developer. Development is usually performed at 25 to 35 ° C. for 10
It takes about 2 seconds to 2 minutes.

[0071]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. Examples 1-4 A 0.24 mm thick aluminum plate (material 1050, tempered H16) was degreased in a 5% by weight aqueous sodium hydroxide solution at 60 ° C. for 1 minute, and then 0.5 mol / mol. In a hydrochloric acid solution having a concentration of 1 liter, a temperature of 28 ° C. and a current density of 6
Electrolytic etching was performed under the conditions of 0 A / dm ² and a processing time of 40 seconds. Then, after subjecting to a desmutting treatment at 60 ° C. for 12 seconds in a 4% by weight aqueous sodium hydroxide solution,
0% by weight sulfuric acid solution, temperature 20 ° C, current density 3.5A
Anodizing treatment was performed under the conditions of / dm ² and a treatment time of 1 minute. Further, a hot water sealing treatment was performed with hot water of 80 ° C. for 20 seconds to prepare an aluminum plate for a lithographic printing plate support.
The average roughness Ra of this plate measured by a surface roughness meter (“SE-3DH”, manufactured by Kosaka Laboratory Co., Ltd.) was 0.60 μm.
A photosensitive solution comprising the following components was applied to the surface of the obtained aluminum plate support with a wire bar, dried at 100 ° C. for 1 minute, and then heat-treated at 55 ° C. for 16 hours to obtain a photosensitive planographic printing plate. . The coating amount was 2.5 g / m ² .

(Photosensitive solution) Polymer compound: phenol: m-cresol: p-cresol (20:50:30 molar ratio) co-condensed with formaldehyde 100 parts by weight of novolak resin (Mw7000) Light-to-heat conversion substance: listed in Table 1 Compounded amount described in Table 1-Colored material: 10 parts by weight of crystal violet lactone-Solvent: 900 parts by weight of methyl cellosolve

Next, using a photosensitive lithographic exposure apparatus (Crescent 3030T manufactured by Gerber Co.) using a 1064 nm semiconductor laser as a light source, the sample was converted to halftone images of 200 lines and 1-99% with various exposure energies. A printing plate which is exposed to an image and then developed at 28 ° C. using an alkaline developing solution (a 10-fold diluted solution of DP-4 manufactured by Fuji Photo Film Co., Ltd.) to reproduce a 1-99% halftone image. Was prepared. The sensitivity was evaluated using the exposure amount on the lithographic printing plate on which a 3% halftone image was reproduced. The lower the exposure, the higher the sensitivity.

Comparative Example 1 The near-infrared light-to-heat conversion material in Example 1 was replaced with SS-3 described below.
A photosensitive sample was prepared in the same manner except that the sample was changed to. SS-
Sample No. 3 had low solubility in the solvent for solvent coating, and coating defects in which undissolved crystal particles remained in the photosensitive layer of the coated sample were observed. Further, this sample was evaluated in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 2 The near-infrared light-to-heat conversion material in Example 1 was replaced with SS-4 described below.
A photosensitive sample was prepared in the same manner except that the sample was changed to. In the photosensitive layer of the photosensitive sample, coating defects due to undissolved crystal particles of SS-4 were observed as in Comparative Example 1. This sample was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0076]

[Table 1] 1) (*) in parenthesis in Table 1 indicates parts by weight. 2) F in Table 1 indicates that even at 500 mJ / cm ² , the photosensitive layer flowed over the entire surface and no image was formed. In other words, when development is performed after exposure of 500 mJ / cm ² , if the sample is immersed in a developing solution until the exposed portion is removed, all the unexposed portions of the photosensitive layer are also removed.

[0077]

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[0078]

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Examples 5 to 8 In Example 1, the photosensitive solution was changed to the following composition, and an 8-fold diluted solution of DP-4 manufactured by Fuji Photo Film Co., Ltd. was prepared as an alkaline developer, and evaluated. (Photosensitive solution)-Polymer compound (1): 100 parts by weight of novolak resin (Mw5000) obtained by co-condensing phenol: m-cresol: p-cresol (20:50:30 molar ratio) with formaldehyde (2): 10 parts by weight of the following SC-1 ・ Near-infrared light-to-heat conversion material: those described in Table-2 Compounding amount described in Table-2 ・ Coloring material: 10 parts by weight of crystal violet lactone ・ Additive: ・Polyoxyethylene (PEG # 2000: manufactured by Toho Chemical Industry Co., Ltd.) 3 parts by weight ・ cis-1,2-cyclohexanedicarboxylic acid 4 parts by weight ・ Solvent: methyl cellosolve 900 parts by weight

[0080]

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[0081]

[Table 2] 1) In Table 2, parentheses (*) indicate parts by weight.

[0082]

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[0083] SS-5 (compound encompassed in the formula (IV)): compounds of the above structure, where _{^{X - = PF 6 -, R}} a = C 4 H 9 -n SS-6 ( Formula (IV) Embedded image): a compound having the above structure, provided that X ⁻ = PF ₆ ⁻ and R ^a = C ₂ H ₅ −n

[0084]

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SS-7 (compound included in the above formula (IV)): a compound having the above structure, provided that X ⁻ = SbF ₆ ⁻ , R ^b = C ₄ H ₉ −n SS-8 (the above formula (IV) Embedded image): a compound having the above structure, provided that X ⁻ = SbF ₆ ⁻ , R ^b = C ₂ H ₅ −n

Reference Example The samples of Examples 1 to 8 were
After leaving under a white fluorescent lamp of looks for 10 hours, the same sensitivity was obtained by measuring the sensitivity in the same manner.

[0087]

According to the present invention, it is possible to provide a positive photosensitive composition excellent in sensitivity and free from coating defects, and a photosensitive lithographic printing plate using the same. In particular, it is possible to provide a positive photosensitive lithographic printing plate which is excellent in the above-mentioned characteristics in near infrared laser light and can be operated under a white light.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) // C09D 7/12 C09D 7/12 Z 201/00 201/00

Claims (17)

[Claims] 1. A positive photosensitive composition containing a near-infrared light-to-heat conversion material and an alkali-soluble resin, and containing no radically polymerizable monomer, wherein the near-infrared light-to-heat conversion material is N, N-
A positive photosensitive composition comprising a near-infrared absorbing dye having at least one diaryliminium salt skeleton or at least one N, N-diarylaminium salt skeleton in a molecule. 2. A positive photosensitive composition containing an alkali-soluble resin and a near-infrared light-to-heat conversion material and having no radical polymerizability, wherein the near-infrared light-to-heat conversion material is an N, N-diaryliminium salt. A positive photosensitive composition, which is a near-infrared absorbing dye having at least one skeleton or N, N-diarylaminium salt skeleton in a molecule. 3. A photosensitive composition containing an alkali-soluble resin and a near-infrared light-to-heat conversion material and capable of forming a positive image mainly by a change other than a chemical change, wherein the near-infrared light-to-heat conversion material is N, N- A diaryliminium salt skeleton or N,
A positive photosensitive composition comprising a near-infrared absorbing dye having at least one N-diarylaminium salt skeleton in a molecule. 4. In a positive photosensitive composition containing an alkali-soluble resin and a near-infrared light-to-heat conversion material and not containing a photoacid generator, the near-infrared light-to-heat conversion material is an N, N-diaryliminium salt. A positive photosensitive composition, which is a near-infrared absorbing dye having at least one skeleton or N, N-diarylaminium salt skeleton in a molecule. 5. A positive-type photosensitive composition containing an alkali-soluble resin and a near-infrared light-to-heat conversion material and having substantially no sensitivity to ultraviolet light, wherein the near-infrared light-to-heat conversion material is N, N
A positive photosensitive composition, which is a near-infrared absorbing dye having at least one diaryliminium salt skeleton or at least one N, N-diarylaminium salt skeleton in a molecule. 6. A positive photosensitive composition containing an alkali-soluble resin and a near-infrared light-to-heat conversion material, wherein the near-infrared light-to-heat conversion material is an N, N-diaryliminium salt skeleton or an N, N-diarylamido salt. A near-infrared absorbing dye having at least one chromium salt skeleton in the molecule, and the composition does not change its solubility in an alkali developer when left for 10 hours under a white light having a light intensity of 400 lux. A positive photosensitive composition characterized by the following. 7. The near-infrared light-to-heat conversion substance is a near-infrared absorbing dye having one or two N, N-diaryliminium salt skeletons or one or more N, N-diarylaminium salt skeletons. Item 7. The positive photosensitive composition according to any one of Items 1 to 6. 8. The aryl group contained in the N, N-diaryliminium salt skeleton or the N, N-diarylaminium salt skeleton is a phenyl group or a naphthyl group, and at least one of the aryl groups is an alkyl group as a substituent. The positive photosensitive composition according to any one of claims 1 to 7, which has an amino group which may be substituted with: 9. The positive photosensitive composition according to claim 1, wherein the near-infrared absorbing dye contains 3 to 6 benzene rings in its structure. . 10. The near-infrared light-to-heat conversion material has the following general formula:
Characterized by being a dye represented by (I) to (IV)
The positive photosensitive composition according to claim 1. Embedded imageEmbedded imageEmbedded image(Where R¹ ~ R⁸ Independently has a hydrogen atom and a substituent
Optionally having an alkyl group having 1 to 15 carbon atoms and a substituent
An aromatic hydrocarbon ring group having 6 to 15 carbon atoms which may be
Is a heterocyclic ring having 4 to 15 carbon atoms which may have a substituent
Group, R⁹ ~ R¹⁶Independently has a hydrogen atom or a substituent
An alkyl group having 1 to 15 carbon atoms,¹⁷~ R²⁰Is
Independently a hydrogen atom, carbon number 1 to 1 which may have a substituent
15 alkyl groups, 6 carbon atoms which may have a substituent
To 15 aromatic hydrocarbon ring groups, which may have a substituent
May have a heterocyclic group having 4 to 15 carbon atoms and substituents.
Acyl groups having 2 to 15 carbon atoms,
C2-15 alkoxycarbonyl group, hydroxyl group,
Acyloxy having 2 to 15 carbon atoms which may have a substituent
Si, cyano, chlorine, bromine, iodine or
Represents a fluorine atom; ¹ And R⁹ , R^Two And R^Ten, R^Three When
R¹¹, R^Four And R¹², R^Five And R¹³, R⁶ And R¹⁴, R ⁷ And R
^Fifteen, And R⁸ And R¹⁶Is directly or an oxygen atom,
Linked via at least one of a sulfur atom and an amino group
And may form a ring structure.^-And Y^-Is it
Each represents a counter anion. In addition, the electronic bond in the formula (I)
(...) indicates a resonance state with another electronic bond. ) 11. The near-infrared absorbing dye represented by the following general formula (I ′)
A dye represented by the formula (IV ′):
The positive photosensitive composition according to claim 1. Embedded imageEmbedded image(In the formulas (I ′) to (IV ′), R¹ ~ R⁸ Is an independent hydrogen source
And alkyl having 1 to 15 carbon atoms which may have a substituent
, An aromatic group having 6 to 15 carbon atoms which may have a substituent
Group hydrocarbon ring group or carbon number which may have a substituent
4 to 15 heterocyclic groups, R⁹ ~ R¹⁶Is independently a hydrogen atom or
C1-C15 alkyl optionally having substituent (s)
Group, R¹⁷~ R²⁰Has a hydrogen atom and a substituent independently
Having an alkyl group having 1 to 15 carbon atoms, which may have a substituent
An aromatic hydrocarbon ring group having 6 to 15 carbon atoms which may be substituted
An optionally substituted heterocyclic group having 4 to 15 carbon atoms,
An acyl group having 2 to 15 carbon atoms which may have a group,
C2-C15 alkoxycarb optionally having a group
Carbonyl group, hydroxyl group, carbon atom 2 which may have a substituent
~ 15 acyloxy groups, cyano groups, chlorine atoms, bromine atoms
Represents an atom, an iodine atom or a fluorine atom;¹ And R⁹ ,
R^Two And R^Ten, R^Three And R¹¹, R^Four And R¹², R^Five And R ¹³, R
⁶ And R¹⁴, R⁷ And R^Fifteen, And R⁸ And R¹⁶Are each directly
Alternatively, at least oxygen, sulfur and amino groups
May also be connected via one to form a cyclic structure,
X^-And Y^-Each represents a counter anion. Also, the formula
The electronic bond (...) in (I) is a resonance state with other electronic bonds.
Is shown. ) 12. In the general formulas (I ′) to (IV ′), R
^{1 to} R ⁸ are independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ^{9 to} R ¹⁶ are a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and R ^{17 to} R ²⁰ are each a hydrogen atom. Certain claim 1
2. The positive photosensitive composition according to item 1. 13. The positive photosensitive composition according to claim 12, wherein the near-infrared absorbing dye is a dye represented by formula (I ′) or (II ′). 14. The positive photosensitive composition according to claim 1, wherein the alkali-soluble resin is an alkali-soluble organic polymer having a phenolic hydroxyl group. 15. The positive photosensitive composition according to claim 14, wherein the alkali-soluble resin is a novolak resin. 16. A photosensitive lithographic printing plate comprising a support and a layer comprising the positive photosensitive composition according to claim 1. Description: 17. A method of forming a positive image, comprising exposing the photosensitive lithographic printing plate according to claim 16 to laser light having a wavelength range of 650 to 1300 nm, and developing the resultant with an alkali developer to form a positive image.