JP4295648B2 - Image forming material - Google Patents

Description

  The present invention relates to an image forming material, and more particularly to a positive image forming material useful as a positive lithographic printing plate precursor for infrared laser for direct plate making, which can be directly made from a digital signal of a computer or the like.

  In recent years, the development of lasers has been remarkable, and in particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared can easily obtain high-power and small-sized ones. These lasers are very useful as an exposure light source when directly making a plate from digital data such as a computer.

In a conventionally known positive photosensitive image forming material for infrared laser for direct plate making, a novolak resin or the like is mainly used as an aqueous alkali solution-soluble resin.
For example, as a positive-type photosensitive image forming material, an alkali aqueous solution-soluble resin having a phenolic hydroxyl group such as a novolak resin, a substance that absorbs light and generates heat, various onium salts, quinonediazide compounds, etc. A positive photosensitive compound is added, and the positive photosensitive compound acts as a dissolution inhibitor that substantially lowers the solubility of the aqueous alkali-soluble resin in the image area, and dissolves by heat in the non-image area. There has been disclosed a technique in which an image is formed such that the blocking ability is not developed and can be removed by development (see, for example, Patent Document 1).

  Further, the positive photosensitive image forming material is composed of a substance that generates heat by absorbing light and a resin whose alkali aqueous solution solubility is changed by the heat. Low and non-image areas are disclosed in which an aqueous alkali solution becomes highly soluble by heat and can be removed by development to form an image (see Patent Documents 2 and 3).

  In the conventional lithographic printing plate precursor, the novolak resin interacts strongly with the dissolution inhibitor, so that the difference in solubility in the developer between the exposed area and the unexposed area becomes large, and the ink acceptability is excellent. For reasons, it is particularly preferably used. For the same reason, novolak resin is also used for positive-type photosensitive image forming materials for infrared lasers. As the novolak resin, a resin obtained by polymerizing phenols such as phenol, cresol and xylenol using formaldehyde under acidic conditions is generally used.

A wide variety of compounds have been studied as dissolution inhibitors, and it is known that onium salt-type dissolution inhibitors exhibit a very strong dissolution inhibitory ability. However, the addition of a general onium salt compound can improve the alkali resistance of unexposed areas due to its high ability to suppress dissolution, but it has been problematic in that, for example, it causes a decrease in sensitivity due to handling under white light. . As a means for overcoming this problem, a new photosensitive material using a specific onium salt excellent in decomposability by exposure has been disclosed (for example, see Patent Document 4 below). Although such an onium salt exhibits excellent characteristics that achieve both high dissolution inhibiting ability and high sensitivity, the development process is not performed immediately after exposure, and when the exposed plate material is developed after a predetermined time, It has been found that this causes a new problem that developability deteriorates. Such a decrease in developability with time after exposure is a problem in the plate making process, and improvement is required. Hereinafter, in this specification, the degree of change in developability after exposure is expressed by the quality of “storability”, and the greater the decrease in developability is referred to as “the worse the seizure property”.
JP-A-7-285275 International Publication No. 97/39894 Pamphlet European Patent Application No. 0823327A2 JP 2002-278050 A

  The object of the present invention made in consideration of the problems of the prior art is useful for a heat mode-compatible positive planographic printing plate precursor, and a difference in solubility in a developing solution between an exposed area and an unexposed area (solubility) Discrimination: hereinafter referred to as “dissolvable discrimination” as appropriate) and providing a positive type image-forming material having a small degree of change in developability with time after exposure, that is, good shrinkage. There is to do.

  As a result of the study, the inventors of the present invention have applied a novolac type phenol resin containing phenol as a structural unit and a sulfonium salt to the image forming layer in combination, thereby reducing the shrinkage without reducing the sensitivity and the development latitude. As a result, the present invention has been completed.

That is, the image forming material of the present invention comprises (A) a novolak type phenol resin containing phenol as a structural unit (hereinafter, referred to as “specific novolak resin” as appropriate), (B) a photothermal conversion agent, and (C) It has an image forming layer containing a sulfonium salt represented by the general formula (II) described in detail below .

In general, if the development latitude is sacrificed, the printing quality can be improved. Surprisingly, however, in the present invention, by adopting the above-described configuration, it is possible to improve the shrinkage while achieving both sensitivity and development latitude.
Although the action of the present invention is not clear, by adding a sulfonium salt having a specific substituent to the image forming layer, it can be used with a specific novolak resin, particularly a phenol as its structural unit, as a film forming component of the image forming layer. The interaction enhances the resistance of the image portion to the developer, makes the image portion less susceptible to damage by a more active developer, and forms an image portion having excellent development resistance. Since the sulfonium salt having this specific substituent is excellent in thermal decomposability and its decomposition reaction is irreversible, the development resistance due to the sulfonium salt is quickly lost by decomposition in the infrared laser exposure region. Thus, it is considered that developability is improved and an excellent solubility disc is achieved.
On the other hand, in general, in the exposed portion of the positive type image forming layer, the decrease in developability with time is caused by the interaction between the novolak resin and the dissolution inhibitor disappearing by exposure, and then the interaction is re-formed with time. In the present invention, the sulfonium salt added to the image forming layer is rapidly decomposed in the infrared laser exposure region, and the anti-resistance attributed to the sulfonium salt having a specific substituent is used in the present invention. The developability disappears and the developability in the exposed area is improved, but the loss of developability function due to the decomposition of the sulfonium salt is irreversible, so that the decrease in developability with time after exposure is also improved. Conceivable.

In the present invention, “corresponding to heat mode” means that recording by heat mode exposure is possible.
The definition of the heat mode exposure in this invention is explained in full detail. Hans-Joachim Time, IS & Ts NIP 15: 1999 International Conference on Digital Printing Technologies. As described in p209, a photoabsorbing substance (for example, a dye) is photoexcited in a photosensitive material and undergoes a chemical or physical change to form a chemical or physical change from the photoexcitation of the photoabsorbing substance that forms an image. It is known that there are two modes in the above process. One is that the photo-excited light-absorbing substance is deactivated by some photochemical interaction (for example, energy transfer, electron transfer) with other reactants in the photosensitive material, and as a result, the activated reactant is The so-called photon mode that causes the chemical or physical change necessary for the above-described image formation, and the other is that the photo-excited light-absorbing material generates heat and deactivates, and the reaction material is converted into the above-described using the heat. This is a so-called heat mode that causes a chemical or physical change necessary for image formation. In addition, there are special modes such as ablation that explosively scatters by the energy of light gathered locally, and multiphoton absorption in which one molecule absorbs many photons at once, but they are omitted here.

  The exposure process using each of the above modes is called photon mode exposure and heat mode exposure. The technical difference between photon mode exposure and heat mode exposure is whether or not the energy amount of several photons to be exposed can be added to the target energy amount of the reaction. For example, consider that a certain reaction is caused by using n photons. In photon mode exposure, photochemical interaction is used, so that one-photon energy cannot be added together due to the requirement of quantum energy and momentum conservation laws. That is, in order to cause some kind of reaction, a relationship of “one photon energy amount ≧ reaction energy amount” is necessary. On the other hand, in heat mode exposure, heat is generated after light excitation, and light energy is converted into heat and used, so that the amount of energy can be added. Therefore, the relationship “energy amount of n photons ≧ energy amount of reaction” is sufficient. However, this energy amount addition is restricted by thermal diffusion. That is, if the next photoexcitation-deactivation process occurs and the heat is generated before the heat escapes from the exposed portion (reaction point) of interest now, due to thermal diffusion, the heat is surely accumulated and added, and the temperature of that portion increases. Leads to. However, when the next heat generation is slow, the heat escapes and does not accumulate. In other words, in the heat mode exposure, even when the same total exposure energy amount is used, the result is different between the case where the high energy amount light is irradiated for a short time and the case where the low energy amount light is irradiated for a long time. It becomes advantageous for accumulation.

Of course, in the photon mode exposure, a similar phenomenon may occur due to the diffusion of the subsequent reactive species, but basically this does not occur.
That is, in terms of the characteristics of the photosensitive material, in the photon mode, the intrinsic sensitivity of the photosensitive material (energy for reaction required for image formation) with respect to the exposure power density (W / cm ² ) (= energy density per unit time). In the heat mode, the intrinsic sensitivity of the photosensitive material increases with respect to the exposure power density. Therefore, when the exposure time is fixed so that the necessary productivity can be maintained in practice as an image recording material, when comparing the modes, the photon mode exposure usually has a high sensitivity of about 0.1 mJ / cm ^2. However, since the reaction occurs at any small exposure amount, the problem of low exposure fogging in the unexposed area is likely to occur. On the other hand, in the heat mode exposure, the reaction does not occur unless the exposure amount is a certain level or more, and usually about 50 mJ / cm ² is required because of the relationship with the thermal stability of the photosensitive material. The problem is avoided.
In fact, in the heat mode exposure, the exposure power density on the plate surface of the photosensitive material is required to be 5000 W / cm ² or more, preferably 10000 W / cm ² or more. However, although not described in detail here, use of a high power density laser of 5.0 × 10 ⁵ W / cm ² or more is not preferable because of problems such as ablation and contamination of the light source.

  According to the present invention, it is possible to provide an image forming material that is useful for a heat mode-compatible positive type lithographic printing plate precursor, that is excellent in solubility and has good shrinkage. By applying this image forming material, it is possible to obtain a positive planographic printing plate precursor which is excellent in development latitude, can be recorded with high sensitivity, and has improved shrinkage.

Hereinafter, the present invention will be described in detail.
The image forming material of the present invention is represented by (A) a novolac type phenol resin containing phenol as a structural unit, (B) a photothermal conversion agent, and (C) a general formula (II) described in detail below on a support. And an image forming layer containing a sulfonium salt.
Below, each component which comprises the image forming layer which concerns on this invention is demonstrated sequentially.

[(A) Novolac-type phenol resin containing phenol as a structural unit]
The image forming layer according to the present invention contains a novolac-type phenol resin (specific novolac resin) containing phenol as a structural unit. The specific novolac resin is not particularly limited as long as it contains phenol as a structural unit in the molecule, but preferably, the phenol as the structural unit is 20 to 90 mol% in the structural unit constituting the novolak resin. It is preferable that it is 31 to 85 mol%, and most preferably in the range of 51 to 80 mol%.

  As such a specific novolac resin, a resin obtained by condensing (A-1) phenol and a substituted phenol represented by the following general formula (I) with an aldehyde is exemplified. As a more preferable embodiment, (A-2) a resin selected from resins obtained by condensing phenol and phenols selected from cresol and xylenol with aldehydes can be mentioned. Here, the number of components of the substituted phenol which is a structural unit other than phenol constituting the specific novolak may be plural.

<(A-1) Resin formed by condensing phenol and substituted phenol represented by the following general formula (I) with aldehydes>
First, a resin obtained by condensing (A-1) phenol and a substituted phenol represented by the following general formula (I) with an aldehyde (hereinafter, appropriately referred to as “(A-1) resin”) will be described in detail. To do.

In general formula (I), R ¹ and R ² each independently represents a hydrogen atom, an alkyl group, or a halogen atom. As an alkyl group, it is preferable that it is a C1-C3 alkyl group, More preferably, it is a C1-C2 alkyl group. The halogen atom is any one of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a chlorine atom or a bromine atom. R ³ represents an alkyl group having 3 to 6 carbon atoms or a cycloalkyl group.

  (A-1) As substituted phenols represented by the general formula (I) used as a resin component, specifically, isopropylphenol, t-butylphenol, t-amylphenol, hexylphenol, cyclohexylphenol, 3-methyl-4-chloro-6-t-butylphenol, isopropyl cresol, t-butyl cresol, t-amyl resol and the like. Among these, t-butylphenol and t-butylcresol are preferable.

  (A-1) Examples of aldehydes used for the resin include aliphatic and aromatic aldehydes such as formaldehyde, acetaldehyde, acrolein, and crotonaldehyde. Among these, formaldehyde or acetaldehyde is preferable.

(A-1) The phenol content in the monomer constituting the resin is preferably 21 to 90 mol%, more preferably 31 to 85 mol%, and most preferably 51 to 80 mol%. .
Moreover, the weight average molecular weight of (A-1) resin becomes like this. Preferably it is 500-50000, Furthermore, it is preferable that it is 700-20000, It is especially preferable that it is 1000-10000.

  The ratio of the (A-1) resin to the total solid content in the image forming layer according to the present invention is preferably 0.1% by mass to 20% by mass, and further 0.2% by mass to 10% by mass. It is preferable that it is 0.2 mass%-5 mass% especially. When the amount is less than 0.1% by mass, the effect of the addition is poor, and when the amount exceeds 20% by mass, the sensitivity tends to decrease.

<(A-2) Resin formed by condensing phenol and phenol selected from cresol and xylenol with aldehydes>
Next, a resin (hereinafter referred to as “(A-2) resin”) obtained by condensing (A-2) phenol and a phenol selected from cresol and xylenol with an aldehyde will be described in detail. explain.

  (A-2) Examples of the aldehydes used in the condensation reaction for obtaining the resin include those described in the description of the (A-1) resin.

  As the (A-2) resin used in the present invention, a novolak resin such as a phenol formaldehyde resin, a phenol / cresol (m-, p-, or m- / p-mixed) mixed formaldehyde resin is preferably exemplified. It is done.

  (A-2) The phenol content in the monomer constituting the resin is preferably 21 to 90 mol%, more preferably 31 to 85 mol%, and particularly preferably 51 to 80 mol%. . Further, it is preferable to contain 10 mol% or more of m-cresol in the monomer.

(A-2) The weight average molecular weight of the resin is preferably 500 to 50,000, more preferably 700 to 20,000, and particularly preferably 1,000 to 10,000. The number average molecular weight is preferably 500 or more, and more preferably 750 to 650,000. The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

  The (A-2) resin used in the present invention is preferably 10% by mass to 95% by mass, and more preferably 20% by mass to 90% by mass, based on the total solid content of the image recording layer of the image forming material. Is preferred. If the content is less than 10% by mass, the effect of improving the printing durability by the burning treatment may be low and cannot be used.

The specific novolak resin such as the (A-1) resin and the (A-2) resin according to the present invention may be used alone or in combination of two or more.
General novolac resins other than the specific novolac resin according to the present invention can be used in combination. In that case, novolak resins other than the specific novolak resin can be mixed in a range of 5 to 50% by mass, preferably 5 to 30% by mass, and in a range of 5 to 20% by mass with respect to the total novolac resin. It is particularly preferred that

  Examples of the method for producing the specific novolak resin according to the present invention include phenols and substituted phenols as described in “New Experimental Chemistry Course [19] Polymer Chemistry [I]” (1993, Maruzen Publishing), Item 300. (For example, (A-1) resin, (A-2) second component cresols mentioned in the description of the resin) in a solvent using an acid as a catalyst and reacting with an aqueous formaldehyde solution, phenol and The o-position or p-position in the substituted phenol component and formaldehyde can be produced by dehydration condensation.

  The dehydration condensation between the o-position or p-position of the phenol and the substituted phenol component and formaldehyde makes the total mass of the phenol and the substituted phenol component 60 to 90% by mass, preferably 70 to 80% by mass. In the solvent solution, the molar ratio of formaldehyde to the total number of moles of phenol and substituted phenol components is 0.2 to 2.0, preferably 0.4 to 1.4, particularly preferably 0.6 to 1.2. In addition, the acid catalyst has a molar ratio with respect to the total number of moles of phenol and substituted phenol components of 0.01 to 0.1, preferably 0.02 to 0.05. It can be performed by adding under temperature conditions and stirring for several hours while maintaining the temperature range. In addition, it is preferable that reaction temperature is the range of 70 to 150 degreeC, and it is more preferable that it is the range of 90 to 140 degreeC.

  Examples of the solvent used include water, acetic acid, methanol, ethanol, 2-propanol, 2-methoxyethanol, ethylpropionate, ethoxyethylpropionate, 4-methyl-2-pentanone, dioxane, xylene, benzene and the like. Is mentioned.

  Examples of the acid catalyst include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, zinc acetate, manganese acetate, cobalt acetate, magnesium methylsulfonate, aluminum chloride, and zinc oxide. Can be mentioned.

  The residual monomer and dimer of the synthesized phenol resin are removed by distillation, and the residual monomer and dimer concentration is preferably distilled to 0.01 to 10% by mass, and may be distilled to 0.01 to 2.0% by mass. Further preferred.

Specific examples [(S-1) to (S-18)] of specific novolak resins preferably used in the present invention are shown below.
(S-1) A polycondensation product of phenol, m-cresol and p-cresol (molar ratio 30:50:20, weight average molecular weight 4000)
(S-2) A polycondensation product of phenol, m-cresol and o-cresol (molar ratio 50:30:20, weight average molecular weight 5500)
(S-3) A polycondensation product of phenol, m-cresol and p-cresol (molar ratio 70:10:20, weight average molecular weight 4500)
(S-4) A polycondensation product of phenol, m-cresol and p-cresol (molar ratio 50:30:20, weight average molecular weight 4200)
(S-5) A polycondensation product of phenol and m-cresol (molar ratio 70:30, weight average molecular weight 4500)
(S-6) A polycondensation product of phenol and p-cresol (molar ratio 60:40, weight average molecular weight 6000)
(S-7) A polycondensation product of phenol and o-cresol (molar ratio 50:50, weight average molecular weight 3900)
(S-8) Condensation polymer of phenol and p-ethylphenol (molar ratio 40:60, weight average molecular weight 4000)
(S-9) A polycondensation product of phenol and p-tertiary butylphenol (molar ratio 80:20, weight average molecular weight 5000)

(S-10) A condensation polymer of phenol and 2,5-xylenol (molar ratio 90:10, weight average molecular weight 8000)
(S-11) A condensation polymer of phenol and 2,3-xylenol (molar ratio 75:25, weight average molecular weight 4400)
(S-12) A condensation polymer of phenol and 2,4-xylenol (molar ratio 80:20, weight average molecular weight 5500)
(S-13) A condensation polymer of phenol and 3,4-xylenol (molar ratio 70:30, weight average molecular weight 7400)
(S-14) A polycondensation product of phenol and p-nonylphenol (molar ratio 30:70, weight average molecular weight 9800)
(S-15) A condensation polymer of phenol and p-phenylphenol (molar ratio 65:45, weight average molecular weight 4000)
(S-16) A polycondensation product of phenol and o-phenylphenol (molar ratio 50:50, weight average molecular weight 4500)
(S-17) A polycondensation product of phenol, m-cresol and 2,5-xylenol (molar ratio 80: 15: 5, weight average molecular weight 5500)
(S-18) A polycondensation product of phenol, m-cresol and p-phenylphenol (molar ratio 40:10:50, weight average molecular weight 4500)
In these, (S-1)-(S-13) are preferable and (S-1)-(S-8) are more preferable.

  In the image forming layer according to the present invention, in addition to the specific novolak resin, a water-insoluble and alkaline water-soluble resin (hereinafter, referred to as “other alkali-soluble resin” as appropriate) can be used in combination. This is preferable from the viewpoint of enlarging the development latitude.

  Examples of other alkali-soluble resins include polyhydroxystyrene, polyhalogenated hydroxystyrene, N- (4-hydroxyphenyl) methacrylamide copolymer, hydroquinone monomethacrylate copolymer, and JP-A-7-28244. Examples thereof include sulfonylimide-based polymers described in the publication, and carboxyl group-containing polymers described in JP-A-7-36184. Other acrylic resins containing phenolic hydroxyl groups as disclosed in JP-A-51-34711, acrylic resins having sulfonamide groups described in JP-A-2-866, urethane-based resins, etc. Various alkali-soluble polymer compounds can also be used.

These other alkali-soluble resins preferably have a weight average molecular weight of 500 to 200,000 and a number average molecular weight of 200 to 60,000.
The other alkali-soluble resins may be used alone or in combination of two or more. The addition amount that can be used in combination is preferably 0.5 to 30% by mass, more preferably 0.5 to 20% by mass in the total solid content of the recording layer.

[(C) Sulfonium salt represented by general formula (II) ]
Image forming layer according to the present invention, you sulphonium salt represented by the following general formula (II).

Wherein ^{(II), R 21, R} 22 and R ^23, rather it may also be the same as or different from each other, it represents a hydrocarbon group having 20 or less carbon atoms having a substituent. Examples of the substituent of the hydrocarbon group include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms. It is done.
(Z ²¹ ) ⁻ represents a residue of a sulfonic acid compound having pKa <5 or a residue of a carboxylic acid compound having pKa <5 .

Specific examples of the sulfonic acid compound constituting the residue represented by (Z ²¹ ) ⁻ include, for example, methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, pentanesulfonic acid, hexanesulfonic acid, Heptanesulfonic acid, octanesulfonic acid, nonanesulfonic acid, decanesulfonic acid, undecanesulfonic acid, dodecanesulfonic acid, tridecanesulfonic acid, tetradecanesulfonic acid, pentadecanesulfonic acid, hexadecanesulfonic acid, heptadecanesulfonic acid, octadecanesulfonic acid, Alkyl sulfonic acids such as nonadecane sulfonic acid, icosane sulfonic acid, henicosane sulphonic acid, docosane sulphonic acid, tricosane sulphonic acid, tetraconsul sulphonic acid, e.g. Acid, trifluoromethanesulfonic acid, chloromethanesulfonic acid, dichloromethanesulfonic acid, trichloromethanesulfonic acid, bromomethanesulfonic acid, dibromomethanesulfonic acid, tribromomethanesulfonic acid, iodomethanesulfonic acid, diiodomethanesulfonic acid, triiodo Methanesulfonic acid, fluoroethanesulfonic acid, difluoroethanesulfonic acid, trifluoroethanesulfonic acid, pentafluoroethanesulfonic acid, chloroethanesulfonic acid, dichloroethanesulfonic acid, trichloroethanesulfonic acid, pentachloroethanesulfonic acid, tribromoethanesulfonic acid, pentabromo Ethanesulfonic acid, triiodoethanesulfonic acid, pentaiodoethanesulfonic acid, fluoropropanesulfonic acid, trifluoropropanesulfone , Heptafluoropropanesulfonic acid, chloropropanesulfonic acid, trichloropropanesulfonic acid, heptachloropropanesulfonic acid, bromopropanesulfonic acid, tribromopropanesulfonic acid, heptabromopropanesulfonic acid, triiodopropanesulfonic acid, heptaiodopropanesulfonic acid, Trifluorobutanesulfonic acid, nonafluorobutanesulfonic acid, trichlorobutanesulfonic acid, nonachlorobutanesulfonic acid, tribromobutanesulfonic acid, nonabromobutanesulfonic acid, triiodobutanesulfonic acid, nonaiodobutanesulfonic acid,

Trifluoropentanesulfonic acid, perfluoropentanesulfonic acid, trichloropentanesulfonic acid, perchloropentanesulfonic acid, tribromopentanesulfonic acid, perbromopentanesulfonic acid, triiodopentanesulfonic acid, periododopentanesulfonic acid, trifluorohexane Sulfonic acid, perfluorohexanesulfonic acid, trichlorohexanesulfonic acid, perchlorohexanesulfonic acid, perbromohexanesulfonic acid, periodohexanesulfonic acid, trifluoroheptanesulfonic acid, perfluoroheptanesulfonic acid, trichloroheptanesulfonic acid, perfluorohexane Chloroheptane sulfonic acid, perbromoheptane sulfonic acid, periodate heptane sulfonic acid, trifluorooctane sulfonic acid, perfluorooctance Phosphonic acid, trichlorooctane sulfonic acid, perchlorooctane sulfonic acid, perbromooctane sulfonic acid, periodooctane sulfonic acid, trifluorononane sulfonic acid, perfluorononane sulfonic acid, trichlorononane sulfonic acid, perchlorononane sulfonic acid, per Bromonotenesulfonic acid, periodononanesulfonic acid, trifluorodecanesulfonic acid, perfluorodecanesulfonic acid, trichlorodecanesulfonic acid, perchlorodecanesulfonic acid, perbromodecanesulfonic acid, periodododecanesulfonic acid, trifluoroundecane Sulfonic acid, perfluoroundecane sulfonic acid, trichloroundecane sulfonic acid, perchloroundecane sulfonic acid, perbromoundecane sulfonic acid, periodoundecane sulfone , Trifluorododecanesulfonic acid, perfluorododecanesulfonic acid, trichlorododecanesulfonic acid, perchlorododecanesulfonic acid, perbromododecanesulfonic acid, periodododecanesulfonic acid, trifluorotridecanesulfonic acid, perfluorotridecanesulfonic acid, trichloro Tridecanesulfonic acid, perchlorotridecanesulfonic acid, perbromotridecanesulfonic acid, periodotridecanesulfonic acid,

Trifluorotetradecanesulfonic acid, perfluorotetradecanesulfonic acid, trichlorotetradecanesulfonic acid, perchlorotetradecanesulfonic acid, perbromotetradecanesulfonic acid, periodotetradecanesulfonic acid, trifluoropentadecanesulfonic acid, perfluoropentadecanesulfonic acid, trichloropentadecanesulfonic acid Acid, perchloropentadecanesulfonic acid, perbromopentadecanesulfonic acid, periodopentadecanesulfonic acid, perfluorohexadecanesulfonic acid, perchlorohexadecanesulfonic acid, perbromohexadecanesulfonic acid, periodohexadecanesulfonic acid, perfluoroheptadecanesulfonic acid Perchloroheptadecanesulfonic acid, perbromoheptadecanesulfonic acid, perio Heptadecanesulfonic acid, perfluorooctadecanesulfonic acid, perchlorooctadecanesulfonic acid, perbromooctadecanesulfonic acid, periodooctadecanesulfonic acid, perfluorononadecanesulfonic acid, perchlorononadecanesulfonic acid, perbromononadecanesulfonic acid, Periodononadecanesulfonic acid, perfluoroicosanesulfonic acid, perchloroicosanesulfonic acid, perbromoicosanesulfonic acid, periodoicosanesulfonic acid, perfluoroheneicosansulfonic acid, perchlorohicosansulfonic acid , Perbromohenicosan sulfonic acid, periodohenicosan sulfonic acid, perfluoro docosan sulfonic acid, perchlorodocosane sulfonic acid, perbromodocosane sulfonic acid, periodo doco sans Phosphonic acid, perfluorotricosansulfonic acid, perchlorotricosansulfonic acid, perbromotricosansulfonic acid, periodotricosanesulfonic acid, perfluorotetraconsansulfonic acid, perchlorotetraconsansulfonic acid, perbromotetracene Consansulfonic acid, haloalkylsulfonic acid such as periododotetraconsansulfonic acid,

  For example, cycloalkylsulfonic acid such as cyclopentanesulfonic acid and cyclohexanesulfonic acid, such as 2-fluorocyclopentanesulfonic acid, 2-chlorocyclopentanesulfonic acid, 2-bromocyclopentanesulfonic acid, 2-iodocyclopentanesulfonic acid 3-fluorocyclopentanesulfonic acid, 3-chlorocyclopentanesulfonic acid, 3-bromocyclopentanesulfonic acid, 3-iodocyclopentanesulfonic acid, 3,4-difluorocyclopentanesulfonic acid, 3,4-dichlorocyclopentane Sulfonic acid, 3,4-dibromocyclopentanesulfonic acid, 3,4-diiodocyclopentanesulfonic acid, 4-fluorocyclohexanesulfonic acid, 4-chlorocyclohexanesulfonic acid, 4-bromocyclohexanesulfonic acid 4-iodocyclohexanesulfonic acid, 2,4-difluorocyclohexanesulfonic acid, 2,4-dichlorocyclohexanesulfonic acid, 2,4-dibromocyclohexanesulfonic acid, 2,4-diiodocyclohexanesulfonic acid, 2,4,6- Trifluorocyclohexanesulfonic acid, 2,4,6-trichlorocyclohexanesulfonic acid, 2,4,6-tribromocyclohexanesulfonic acid, 2,4,6-triiodocyclohexanesulfonic acid, tetrafluorocyclohexanesulfonic acid, tetrachlorocyclohexane Halogenated cycloalkylsulfonic acid such as sulfonic acid, tetrabromocyclohexanesulfonic acid, tetraiodocyclohexanesulfonic acid,

  For example, aromatic aromatic sulfonic acids such as benzenesulfonic acid, nanthalenesulfonic acid, anthracenesulfonic acid, phenanthrenesulfonic acid, pyrenesulfonic acid, such as 2-fluorobenzenesulfonic acid, 3-fluorobenzenesulfonic acid, 4-fluorobenzene Sulfonic acid, 2-chlorobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 4-chlorobenzenesulfonic acid, 2-bromobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 4-bromobenzenesulfonic acid, 2-iodobenzenesulfonic acid, 4-iodobenzenesulfonic acid, 2,4-difluorobenzenesulfonic acid, 2,6-difluorobenzenesulfonic acid, 2,4-dichlorobenzenesulfonic acid, 2,6-dichlorobenzenesulfonic acid, 2,4-dibromobenzenesulfone acid, , 6-Dibromobenzenesulfonic acid, 2,4-diiodobenzenesulfonic acid, 2,6-diiodobenzenesulfonic acid, 2,4,6-trifluorobenzenesulfonic acid, 3,4,5-trifluorobenzenesulfone Acid, 2,4,6-trichlorobenzenesulfonic acid, 3,4,5-trichlorobenzenesulfonic acid, 2,4,6-tribromobenzenesulfonic acid, 3,4,5-tribromobenzenesulfonic acid, 2, 4,6-triiodobenzenesulfonic acid, 3,4,5-triiodobenzenesulfonic acid, pentafluorobenzenesulfonic acid, pentachlorobenzenesulfonic acid, pentabromobenzenesulfonic acid, pentaiodobenzenesulfonic acid, fluoronaphthalenesulfonic acid, Chloronaphthalenesulfonic acid, bromonaphthalenesulfonic acid, iodine De naphthalenesulfonic acid, fluoro anthracene sulfonic acid, chloro anthracene sulfonic acid, bromoanthracene acid, halogenated aromatic contact sulfonic acids such as iodine Anton Sen sulfonic acid,

  For example, p-toluenesulfonic acid, 4-isopropylbenzenesulfonic acid, 3,5-bis (trimethyl) benzenesulfonic acid, 3,5-bis (isopropyl) benzenesulfonic acid, 2,4,6-tris (trimethyl) benzene Alkyl aromatic sulfonic acids such as sulfonic acid and 2,4,6-tris (isopropyl) benzenesulfonic acid, such as 2-trifluoromethylbenzenesulfonic acid, 2-trichloromethylbenzenesulfonic acid, 2-tribromomethylbenzenesulfone Acid, 2-triiodomethylbenzenesulfonic acid, 3-trifluoromethylbenzenesulfonic acid, 3-trichloromethylbenzenesulfonic acid, 3-tribromomethylbenzenesulfonic acid, 3-triiodomethylbenzenesulfonic acid, 4-trifluoro Methylbenzenesulfone 4-trichloromethylbenzenesulfonic acid, 4-tribromomethylbenzenesulfonic acid, 4-triiodomethylbenzenesulfonic acid, 2,6-bis (trifluoromethyl) benzenesulfonic acid, 2,6-bis (trichloromethyl) Benzenesulfonic acid, 2,6-bis (tribromomethyl) benzenesulfonic acid, 2,6-bis (triiodomethyl) benzenesulfonic acid, 3,5-bis (trifluoromethyl) benzenesulfonic acid, 3,5- Halogenated alkyl aromatic sulfonic acids such as bis (trichloromethyl) benzenesulfonic acid, 3,5-bis (tribromomethyl) benzenesulfonic acid, 3,5-bis (triiodomethyl) benzenesulfonic acid, such as benzylsulfone Acid, phenethylsulfonic acid, phenylpropylsulfonic acid, pheny Butyl sulfonic acid, phenyl pentyl sulfonic acid, phenyl hexyl sulfonic acid, phenyl heptyl sulfonate, phenyl octyl sulfonic acid, aromatic aliphatic sulfonic acid such as phenyl nonyl acid,

For example, 4-fluorophenylmethylsulfonic acid, 4-chlorophenylmethylsulfonic acid, 4-bromophenylmethylsulfonic acid, 4-iodophenylmethylsulfonic acid, tetrafluorophenylmethylsulfonic acid, tetrachlorophenylmethylsulfonic acid, tetrabromophenylmethyl Sulfonic acid, tetraiodophenylmethylsulfonic acid, 4-fluorophenylethylsulfonic acid, 4-chlorophenylethylsulfonic acid, 4-bromophenylethylsulfonic acid, 4-iodophenylethylsulfonic acid. 4-fluorophenylpropylsulfonic acid, 4-chlorophenylpropylsulfonic acid, 4-bromophenylpropylsulfonic acid, 4-iodophenylpropylsulfonic acid, 4-fluorophenylbutylsulfonic acid, 4-chlorophenylbutylsulfonic acid, 4-bromophenyl Halogenated aromatic aliphatic sulfonic acids such as butylsulfonic acid and 4-iodophenylbutylsulfonic acid, and alicyclic sulfonic acids such as camphorsulfonic acid and adamantanecarboxylic acid are exemplified.
Of these, trifluoromethanesulfonic acid, p-toluenesulfonic acid, and methanesulfonic acid are particularly preferable from the viewpoints of availability and production suitability.

Specific examples of the carboxylic acid compound constituting the residue represented by the above (Z ²¹ ) ⁻ include, for example, formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, hexanoic acid, Heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, icosanoic acid, heicosanoic acid, docosanoic acid, tricosanoic acid Aliphatic unsaturated carboxylic acids such as fluoroacetic acid, chloroacetic acid, bromoacetic acid, iodoacetic acid, difluoroacetic acid, dichloroacetic acid, dibromoacetic acid, diiodoacetic acid, trifluoroacetic acid, trichloroacetic acid, tribromoacetic acid, triiodoacetic acid, 2- Fluoropropionic acid, 2-chloropropionic acid, 2-bromopropion 2-iodopropionic acid, trifluoropropionic acid, trichloropropionic acid, pentafluoropropionic acid, pentachloropropionic acid, pentabromopropionic acid, pentaiodopropionic acid, 2,2-bis (trifluoromethyl) propionic acid, 2 , 2-bis (trichloromethyl) propionic acid, 2,2-bis (tribromomethyl) propionic acid, 2,2-bis (triiodomethyl) propionic acid, trifluorobutyric acid. Trichlorobutyric acid, pentafluorobutyric acid, heptachlorobutyric acid, heptafluorobutyric acid, heptabromobutyric acid, heptaiodobutyric acid, heptafluoroisobutyric acid, heptachloroisobutyric acid, heptabromoisobutyric acid, heptaiodoisoway acid, trifluorovaleric acid, 5H-perfluorovaleric acid 5H-perchlorovaleric acid, 5H-perbromovaleric acid, 5H-periodovaleric acid, nonafluorovaleric acid, nonachlorovaleric acid, nonabromovaleric acid, nonaiodovaleric acid, trifluorohexanoic acid, trichlorohexanoic acid, perfluorohexanoic acid, perfluorohexanoic acid Chlorohexanoic acid, perbromohexanoic acid, periododohexanoic acid, 7-chlorododecafluoroheptanoic acid, 7-chlorododecachloroheptanoic acid, 7-chlorododecabromoheptanoic acid, 7-chlorododecaiodoheptanoic acid, Li fluoro heptanoic acid, trichloroacetic heptanoic acid, 7H-perfluoroheptanoic acid, 7H-perchlorethylene heptanoic acid, 7H-Per-bromo heptanoic acid, 7H-per-iodo-heptanoic acid,

Trifluorooctanoic acid, trichlorooctanoic acid, pentadecafluorooctanoic acid, pentadecachlorooctanoic acid, pentadecabromooctanoic acid, pentadecaiodooctanoic acid, trifluorononanoic acid, trichlorononanoic acid, 9H-hexadecafluorononanoic acid, 9H-hexadecachlorononanoic acid, 9H-hexadecabromononanoic acid, 9H-hexadecaiodononanoic acid, perfluorononanoic acid, perchlorononanoic acid, perbromononanoic acid, periodononanoic acid, trifluorodecanoic acid, trichlorodecanoic acid , Nonadecafluorodecanoic acid, nonadecachlorodecanoic acid, nonadecabromodecanoic acid, nonadecanoiododecanoic acid, trifluoroundecanoic acid, trichloroundecanoic acid, perfluoroundecanoic acid, perchloroundecanoic acid, perbromo Decanoic acid, periodododecanoic acid, trifluorododecanoic acid, trichlorododecanoic acid, perfluorododecanoic acid, perchlorododecanoic acid, perbromododecanoic acid, periodododecanoic acid, trifluorotridecanoic acid, trichlorotridecanoic acid, perfluorotridecanoic acid Decanoic acid, perchlorotridecanoic acid, perbromotridecanoic acid. Periodotridecanoic acid, trifluorotetradecanoic acid, trichlorotetradecanoic acid, perfluorotetradecanoic acid, perchlorotetradecanoic acid, perbromotetradecanoic acid, periodotetradecanoic acid, trifluoropentadecanoic acid, trichloropentadecanoic acid, perfluoropentadecanoic acid, perfluoropentadecanoic acid Chloropentadecanoic acid, perbromopentadecanoic acid, periodopentadecanoic acid, perfluorohexadecanoic acid, perchlorohexadecanoic acid, perbromohexadecanoic acid, periodohexadecanoic acid, perfluoroheptadecanoic acid, perchloroheptadecanoic acid, perbromoheptadecane Acid, periododoheptadecanoic acid, perfluorooctadecanoic acid, perchlorooctadecanoic acid, perbromooctadecanoic acid, periodooctadecanoic acid, perper Luonoronadecanoic acid, perchlorononadecanoic acid, perbromononadecanoic acid, periodononadecanoic acid, perfluoroicosanoic acid, perchloroicosanoic acid, perbromoicosanoic acid, periodoicosanoic acid, perfluorohenicosane Acid, perchlorohenicosanoic acid, perbromohenicosanoic acid, periodohenicosanoic acid, perfluorodocosanoic acid, perchlorodocosanoic acid, perbromodocosanoic acid, periododocosanoic acid, perfluorotrico Halogenated saturated fatty acid strength rubonic acid such as sanic acid, perchlorotricosanoic acid, perbromotricosanoic acid, periodotricosanoic acid,

  For example, hydroxy aliphatic carboxylic acids such as glycolic acid, lactic acid, glyceric acid, 3-hydroxy-2-methylpropionic acid, such as 3-hydroxy-2- (trifluoromethyl) propionic acid, 3-hydroxy-2- ( Trichloromethyl) propionic acid, 3-hydroxy-2- (tribromomethyl) propionic acid, 3-hydroxy-2- (triiodomethyl) propionic acid, 2-hydroxy-2- (trifluoromethyl) butyric acid, 2-hydroxy Halogenation and droxy aliphatic carboxylic acids such as 2- (trichloromethyl) pathic acid, 2-hydroxy-2- (tribromomethyl) butyric acid, 2-hydroxy-2- (triiodomethyl) butyric acid, such as cyclohexanecarboxylic acid Alicyclic carboxylic acids such as acid, camphoric acid, adamantanoic acid, for example 4-fluoro Hexanecarboxylic acid, 4-chlorocyclohexanecarboxylic acid, 4-bromocyclohexanecarboxylic acid, 4-iodocyclohexanecarboxylic acid, pentafluorocyclohexanecarboxylic acid, pentachlorocyclohexanecarboxylic acid, pentabromocyclohexanecarboxylic acid, pentaiodocyclohexanecarboxylic acid, 4 Halogenated alicyclic such as-(trifluoromethyl) cyclohexanecarboxylic acid, 4- (trichloromethyl) cyclohexanecarboxylic acid, 4- (tribromomethyl) cyclohexanecarboxylic acid, 4- (triiodomethyl) cyclohexanecarboxylic acid carboxylic acid,

  For example, aromatic carboxylic acids such as benzoic acid, naphthoic acid, anthracene carboxylic acid, pyrene carboxylic acid, pyrylene carboxylic acid, bentaphene carboxylic acid, such as fluorobenzoic acid, chlorobenzoic acid, bromobenzoic acid, iodobenzoic acid, Difluorobenzoic acid, dichlorobenzoic acid, dibromobenzoic acid, diiodobenzoic acid, trifluorobenzoic acid, trichlorobenzoic acid, tribromobenzoic acid, triiodobenzoic acid, tetrafluorobenzoic acid, tetrachlorobenzoic acid, tetrabromobenzoic acid, tetraiodobenzoic acid , Pentafluorobenzoic acid, pentachlorobenzoic acid, pentabromobenzoic acid, bentaiodobenzoic acid, fluoronaphthoic acid, chloronaphthoic acid, bromonaphthoic acid, iodonaphthoic acid, perfluoronaphthoic acid, perchloronaphthoic acid, -Bromonaphthoic acid, periodonaphthoic acid, fluoroanthracene carboxylic acid, chloroanthracene carboxylic acid, bromoanthanthene carboxylic acid, iodoanthracene carboxylic acid, perfluoroanthracene carboxylic acid, perchloroanthracene carboxylic acid, perbromoanthracene carboxylic acid, perbromo Halogenated aromatic carboxylic acids such as iodoanthracene carboxylic acid, benzoyl formic acid,

  For example, alkylaromatic carboxylic acids such as toluic acid and 2,4,6-tri (isopropyl) benzoic acid, such as 2-trifluoromethylbenzoic acid, 2-trichloromethylbenzoic acid, 2-tribromomethylbenzoic acid 2-triiodomethylbenzoic acid, 3-trifluoromethylbenzoic acid, 3-trichloromethylbenzoic acid, 3-tribromomethylbenzoic acid, 3-triiodomethylbenzoic acid, 4-trifluoromethylbenzoic acid, 4- Trichloromethylbenzoic acid, 4-tribromomethylbenzoic acid, 4-triiodomethylbenzoic acid, 2-fluoro-4- (trifluoromethyl) benzoic acid, 2-chloro-4- (trichloromethyl) benzoic acid, 2- Bromo-4- (tribromomethyl) benzoic acid, 2,3,4-trifluoro-6- (trifluoromethyl) benzoic acid 2,3,4-trichloro-6- (trichloromethyl) benzoic acid, 2,3,4-tribromo-6- (tribromomethyl) benzoic acid, 2,3,4-triiodo-6- (triiodomethyl) Benzoic acid, 2-iodo-4- (triiodomethyl) benzoic acid, 2,4-bis (trifluoromethyl) benzoic acid, 2,4-bis (trichloromethyl) benzoic acid, 2,4-bis (tribromo) Methyl) benzoic acid, 2,4-bis (triiodomethyl) benzoic acid, 2,6-bis (trifluoromethyl) benzoic acid, 2,6-bis (trichloromethyl) benzoic acid, 2,6-bis (tri Bromomethyl) benzoic acid, 2,6-bis (triiodomethyl) benzoic acid, 3,5-bis (trifluoromethyl) benzoic acid, 3,5-bis (trichloromethyl) benzoic acid, 3,5-bis ( bird Lomomethyl) benzoic acid, 3,5-bis (triiodomethyl) benzoic acid, 2,4,6-tris (trifluoromethyl) benzoic acid, 2,4,6-tris (trichloromethyl) benzoic acid, 2,4 , 6-Tris (tribromomethyl) benzoic acid, 2,4,6-tris (triiodomethyl) benzoic acid, 2-chloro-6-fluoro-3-methylbenzoic acid, trifluoromethylnaphthoic acid, trichloromethylnaphthoate Acid, tribromomethyl naphthoic acid, triiodomethyl naphthoic acid,

Bis (trifluoromethyl) naphthoic acid, bis (trichloromethyl) naphthoic acid, bis (tribromomethyl) naphthoic acid, bis (triiodomethyl) naphthoic acid, tris (trifluoromethyl) naphthoic acid, tris (trichloromethyl) naphthoic acid Acids, tris (tribromomethyl) naphthoic acid, tris (triiodomethyl) naphthoic acid, trifluoromethylanthone carboxylic acid, trichloromethyl anthracene carboxylic acid, tribromomethylanthracene carboxylic acid, triiodomethylanthracene carboxylic acid, etc. Haloalkyl aromatic carboxylic acids, for example, alkoxy aromatic carboxylic acids such as anisic acid, beltramic acid, o-bertramic acid, such as 4-trifluoromethoxybenzoic acid, 4-trichloromethoxybenzoic acid, 4-tribromometh Cibenzoic acid, 4-triiodomethoxybenzoic acid, 4-pentafluoroethoxybenzoic acid, 4-pentachloroethoxybenzoic acid, 4-pentabromoethoxybenzoic acid, 4-pentaiodoethoxybenzoic acid, 3,4-bis ( Trifluoromethoxy) benzoic acid, 3,4-bis (trichloromethoxy) benzoic acid, 3,4-bis (tribromomethoxy) benzoic acid, 3,4-bis (triiodomethoxy) benzoic acid, 2,5-bis (2,2,2-trifluoroethoxy) benzoic acid, 2,5-bis (2,2,2-trichloroethoxy) benzoic acid, 2,5-bis (2,2,2-tribromoethoxy) benzoic acid Haloalkoxyaromatic carboxylic acids such as 2,5-bis (2,2,2-triiodoethoxy) benzoic acid, such as salicylic acid, o-pyrocatechuic acid, α-reso Hydroxy aromatic carboxylic acids such as lucylic acid, gentisic acid, α-resorcylic acid, protocatechuic acid, α-resorcylic acid, gallic acid, for example, hydroxyalkoxy aromatic carboxylic acids such as vanillic acid, isovanillic acid, for example, trinitrobenzoic acid Etroaromatic carboxylic acids such as, for example, amino aromatic carboxylic acids such as anthranilic acid, such as α-toluic acid, hydrocinnamic acid, hydroatropic acid, 3-phenylpropionic acid, 4-phenylbutyric acid, 5-phenylpentanoic acid Araliphatic carboxylic acids such as 6-phenylhexanoic acid, 7-phenylheptanoic acid, 6- (2-naphthyl) hexanoic acid, for example, hydroxyaromatic carboxylic acids such as homogentisic acid, such as mandelic acid, benzylic acid , Atrolactic acid, tropic acid, atroglyceric acid, etc. Group hydroxyalkylcarboxylic acids such as 2-formylacetic acid, acetoacetic acid, 3-benzoylpropionic acid, 4-formylbutyric acid, 3-oxovaleric acid, 5-oxovaleric acid, 3,5-dioxovaleric acid, 6- Formylhexanecarboxylic acid, 2-oxo-1-cyclohexanecarboxylic acid, 4- (2-oxobutyl) benzoic acid, p- (3-formylpropyl) benzoic acid, 4-formylphenylacetic acid, β-oxocyclohexanepropionic acid, pyruvin Examples include oxocarboxylic acids such as acids.
Among these, benzoyl formic acid, acetic acid, and benzoic acid are particularly preferable.

Specific examples of the sulfonium salt represented by the general formula (II) that can be suitably used in the present invention [Exemplary compounds (66) to (78), (83) to (89), (94) and (101)] However, the present invention is not limited to this.

The sulfonium salt represented by the general formula (II) used in the present invention preferably has a maximum absorption wavelength of 400 nm or less, and more preferably 360 nm or less. By setting the absorption wavelength in the ultraviolet region in this way, the image recording material can be handled under white light.

The sulfonium salt compound represented by the general formula (II) may be used alone or in combination of two or more. Moreover, these sulfonium salts may be added to the same layer as other components, or another layer may be provided and added thereto.
Examples of the sulfonium salt represented by the general formula (II) preferably used in the present invention include those in which the counter anion is a sulfonate anion or a carboxylate anion.
These sulfonium salts are 0.1 to 50% by weight, preferably 0.5 to 40% by weight, particularly preferably 1%, based on the total solid content of the positive type image recording layer, from the viewpoint of sensitivity and soiling property of the non-image area. It can be added at a ratio of ˜30% by weight.

[(B) Photothermal conversion agent]
The image forming layer according to the present invention contains (B) a photothermal conversion agent.
The (B) photothermal conversion agent used in the present invention is not particularly limited as long as it is a substance that absorbs light energy irradiation rays used for recording and generates heat, but it can be used without limitation. From the viewpoint of compatibility with a high-power laser, an infrared-absorbing dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm is preferable.

[Infrared absorbing dye or pigment]
As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, naphthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, (thio) pyrylium salts And dyes such as metal thiolate complexes, indoaniline metal complex dyes, oxonol dyes, diimonium dyes, aminium dyes, croconium dyes, and intermolecular CT dyes.

Examples of preferable dyes include cyanine dyes described in, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and the like. ,
Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595,
JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60- Naphthoquinone dyes described in Japanese Patent No. 63744
Squarylium dyes described in JP-A-58-112792, etc.,
Cyanine dyes described in British Patent 434,875,
Etc.

  Further, near infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used, and substituted aryl benzoates described in US Pat. No. 3,881,924 are also preferably used. (Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, JP-A-58-220143 No. 59-41363, No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, JP-A 59-216146 Cyanine dyes described in US Pat. No. 4,283,475, pentamethine thiopyrylium salt described in US Pat. No. 4,283,475, etc. Pyrylium compounds disclosed in JP same 5-19702 are also preferably used.

  Moreover, as another example preferable as a dye, the near-infrared absorptive dye described as the formula (I) and (II) in US Patent 4,756,993 can be mentioned.

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes.

  Furthermore, the dyes represented by the following general formulas (a) to (f) are preferable because of excellent photothermal conversion efficiency, and in particular, the cyanine dye represented by the following general formula (a) is used in the present invention. It is most preferable because it gives high interaction with the alkali-soluble resin and is excellent in stability and economy.

In general formula (a), R ¹ and R ² each independently represents an alkyl group having 1 to 12 carbon atoms, and an alkoxy group, an aryl group, an amide group, an alkoxycarbonyl group, a hydroxyl group, sulfo group on the alkyl group. The substituent may be selected from a group and a carboxyl group. Y ¹ and Y ² each independently represent oxygen, sulfur, selenium, a dialkylmethylene group or —CH═CH—. Ar ¹ and Ar ² each independently represent an aromatic hydrocarbon group, which may have a substituent selected from an alkyl group, an alkoxy group, a halogen atom, and an alkoxycarbonyl group, and is adjacent to Y ¹ and Y ² The aromatic ring may be condensed with two consecutive carbon atoms.

  In general formula (a), X represents a counter ion necessary for charge neutralization, and is not always necessary when the dye cation has an anionic substituent and charge neutralization is not necessary. Q represents a polymethine group selected from a trimethine group, a pentamethine group, a heptamethine group, a nonamethine group or an undecamethine group, and is preferably a pentamethine group, a heptamethine group or a nonamethine group from the viewpoint of wavelength suitability and stability for infrared rays used for exposure. It is preferable in terms of stability to have a cyclohexene ring or a cyclopentene ring containing three consecutive methine chains on any carbon.

  In general formula (a), Q is an alkoxy group, aryloxy group, alkylthio group, arylthio group, dialkylamino group, diarylamino group, halogen atom, alkyl group, aralkyl group, cycloalkyl group, aryl group, oxy group, It may be substituted with an iminium base, a group selected from substituents represented by the following general formula (2). Preferred substituents include halogen atoms such as chlorine atoms, diarylamino groups such as diphenylamino groups, phenylthio And arylthio groups such as groups.

In General Formula (2), R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Y ³ represents an oxygen atom or a sulfur atom.

  Of the cyanine dyes represented by the general formula (a), heptamethine cyanine represented by the following general formulas (a-1) to (a-4) is particularly preferable when exposed to infrared rays having a wavelength of 800 to 840 nm. Mention may be made of pigments.

In general formula (a-1), X ¹ represents a hydrogen atom or a halogen atom. R ¹ and R ² each independently represents a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the image-forming layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered It is particularly preferable that a ring or a 6-membered ring is formed.

In general formula (a-1), Ar ¹ and Ar ² may be the same or different, and each represents an aromatic hydrocarbon group that may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion necessary for charge neutralization, and Za ⁻ is not necessary when the dye has an anionic substituent in its structure and charge neutralization is not necessary. . Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, a tetrachlorate ion, in view of the storage stability of the recording layer coating solution. Fluoroborate ion, hexafluorophosphate ion, and sulfonate ion. The heptamethine dye represented by the general formula (a-1) can be suitably used for a positive type image forming material, and in particular, a so-called interaction release type positive photosensitive material combined with an alkali-soluble resin having a phenolic hydroxyl group. Is preferably used.

In general formula (a-2), R ¹ and R ² each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ¹ and R ² are bonded to each other to form a ring structure. The ring to be formed is preferably a 5-membered ring or a 6-membered ring, and a 5-membered ring is particularly preferable. Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Preferred substituents on the aromatic hydrocarbon group include hydrocarbon groups having 12 or less carbon atoms, halogen atoms, alkoxy groups having 12 or less carbon atoms, alkoxycarbonyl groups, alkylsulfonyl groups, and halogenated groups. An alkyl group etc. are mentioned, An electron withdrawing substituent is especially preferable. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. R ⁹ and R ¹⁰ may be the same or different and each may have a substituent, an aromatic hydrocarbon group having 6 to 10 carbon atoms, an alkyl group having 1 to 8 carbon atoms, a hydrogen atom Alternatively, R ⁹ and R ¹⁰ may be bonded to each other to form a ring having the following structure.

As R < ⁹ > and R < ¹⁰ > in general formula (a-2), aromatic hydrocarbon groups, such as a phenyl group, are the most preferable among the above.
X ⁻ is a counter anion necessary for charge neutralization and has the same definition as Za ⁻ in the general formula (a-1).

In general formula (a-3), R ^{1 to} R ⁸ , Ar ¹ , Ar ² , Y ¹ , Y ² and X ⁻ have the same meanings as those in general formula (a-2). Ar ³ represents an aromatic hydrocarbon group such as a phenyl group or a naphthyl group, or a monocyclic or polycyclic heterosphere group containing at least one of nitrogen, oxygen, and sulfur atoms, and is a thiazole type, a benzothiazole type Naphthothiazole, thianaphtheno-7,6,4,5-thiazole, oxazole, benzoxazole, naphthoxazole, selenazole, benzoselenazole, naphthselenazole, thiazoline, 2-quinoline, 4-quinoline, 1-isoquinoline, 3-isoquinoline, benzimidazole, 3,3-dialkylbenzoindolenin, 2-pyridine, 4-pyridine, 3,3-dialkylbenzo [e] indole , Tetrazole, triazole, pyrimidine, and thiadiazole Heterocyclic group is preferable to be, include the following structures Particularly preferred heterocyclic groups.

In general formula (a-4), R ^{1 to} R ⁸ , Ar ¹ , Ar ² , Y ¹ and Y ² have the same meanings as in general formula (a-2). R ¹¹ and R ¹² may be the same or different and each represents a hydrogen atom, an allyl group, a cyclohexyl group, or an alkyl group having 1 to 8 carbon atoms. Z represents an oxygen atom or a sulfur atom.

  Specific examples of the cyanine dye represented by formula (a) that can be preferably used in the present invention include those exemplified below, and paragraph numbers [0017] to [0019] of JP-A No. 2001-133969. And paragraph numbers [0012] to [0038] of JP-A No. 2002-40638 and paragraph numbers [0012] to [0023] of JP-A No. 2002-23360.

In the general formula (b), L represents a methine chain having 7 or more conjugated carbon atoms, the methine chain may have a substituent, and the substituents may be bonded to each other to form a ring structure. Good. Zb ⁺ represents a counter cation. Preferred counter cations include ammonium, iodonium, sulfonium, phosphonium, pyridinium, alkali metal cations (Na ⁺ , K ⁺ , Li ⁺ ) and the like. R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ are each independently a hydrogen atom or halogen atom, cyano group, alkyl group, aryl group, alkenyl group, alkynyl group, carbonyl group, thio group, sulfonyl group, sulfinyl group, oxy group Or a substituent selected from amino groups, or a combination of two or three of these, and may be bonded to each other to form a ring structure. Here, in general formula (b), those in which L represents a methine chain having 7 conjugated carbon atoms and those in which R ^{9 to} R ¹⁴ and R ^{15 to} R ²⁰ all represent hydrogen atoms are easily available. It is preferable from the viewpoint of effect.

  Specific examples of the dye represented by formula (b) that can be suitably used in the present invention include those exemplified below.

In general formula (c), Y ³ and Y ⁴ each represent an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom. M represents a methine chain having 5 or more conjugated carbon atoms. R ^{21 to} R ²⁴ and R ^{25 to} R ²⁸ may be the same or different, and are each a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a carbonyl group, a thiol group, Represents a group, a sulfonyl group, a sulfinyl group, an oxy group, or an amino group. Further, wherein Za ^- include a counter anion, Za in the general formula (a-1) ^- synonymous.

  In the present invention, specific examples of the dye represented by formula (c) that can be suitably used include those exemplified below.

In general formula (d), R ^{29 to} R ³² each independently represent a hydrogen atom, an alkyl group, or an aryl group. R ³³ and R ³⁴ each independently represents an alkyl group, a substituted oxy group, or a halogen atom. n and m each independently represent an integer of 0 to 4. R ²⁹ and R ³⁰ , or R ³¹ and R ³² may be bonded to each other to form a ring, and R ²⁹ and / or R ³⁰ is R ³³ and R ³¹ and / or R ³² is R ³⁴ taken together, may form a ring, further, when R ³³ or R ³⁴ there are a plurality, R ³³ or between R ³⁴ each other may be bonded to each other to form a ring. X ² and X ³ each independently represent a hydrogen atom, an alkyl group, or an aryl group. Q is a trimethine group or a pentamethine group which may have a substituent, and may form a ring structure together with a divalent organic group. Zc ⁻ represents a counter anion and has the same meaning as Za ⁻ in the general formula (a-1).

  In the present invention, specific examples of the dye represented by the general formula (d) that can be suitably used include those exemplified below.

In the general formula (e), R ^{35 to} R ⁵⁰ each independently represent a hydrogen atom or a substituent, which may have a halogen atom, a cyano group, an alkyl group, an aryl group, an alkenyl group, an alkynyl group, a hydroxyl group, A carbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxy group, an amino group, and an onium salt structure are shown. M represents two hydrogen atoms or metal atoms, a halometal group, and an oxymetal group, and the metal atoms contained therein include IA, IIA, IIIB, IVB group atoms of the periodic table, first, second, second Three-period transition metals and lanthanoid elements may be mentioned, among which copper, nickel, magnesium, iron, zinc, tin, cobalt, aluminum, titanium, and vanadium are preferable, and vanadium, nickel, zinc, and tin are particularly preferable. These metal atoms may be bonded to an oxygen atom, a halogen atom or the like in order to make the valence appropriate.

  In the present invention, specific examples of the dye represented by formula (e) that can be suitably used include those exemplified below.

In the general formulas (f-1) and (f-2), R ^{51 to} R ⁵⁸ each independently represent a hydrogen atom or an alkyl group or an aryl group that may have a substituent. X ⁻ has the same meaning as in general formula (a-2).

  In the present invention, specific examples of the dye represented by the general formula (d) that can be suitably used include those exemplified below.

  Other photothermal conversion agents include dyes having a plurality of chromophores described in JP-A-2001-242613, JP-A-2002-97384, and U.S. Pat. No. 6,124,425. Suitable are pigments in which a chromophore is covalently linked to a molecular compound, an anionic dye described in US Pat. No. 6,248,893, a dye having a surface orientation group described in JP-A-2001-347765, etc. Can be used.

  Examples of the pigment used as the photothermal conversion agent in the present invention include commercially available pigments and Color Index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technical Association, published in 1977), “Latest Pigment Applied Technology”. (CMC Publishing, published in 1986) and “Printing Ink Technology”, published by CMC Publishing, published in 1984).

  Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments In addition, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like can be used. Among these pigments, carbon black is preferable.

  These pigments may be used without surface treatment or may be used after surface treatment. The surface treatment method includes a method of surface coating with a resin or wax, a method of attaching a surfactant, a method of bonding a reactive substance (eg, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above-mentioned surface treatment methods are described in “Characteristics and Applications of Metal Soap” (Shobobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle diameter of the pigment is preferably in the range of 0.01 μm to 10 μm, preferably in the range of 0.05 μm to 1 μm, from the viewpoints of stability in the image forming layer coating solution and uniformity of the formed image forming layer. It is more preferable that it is in the range of 0.1 μm to 1 μm.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill, and a pressure kneader. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  These pigments or dyes are 0.01 to 50% by mass, preferably 0.1 to 10% by mass, particularly preferably 0.5 to 10% by mass, based on the total solid content constituting the image forming layer (recording layer). In the case of 10 mass% and a pigment, it can be added particularly preferably at a ratio of 0.1 to 10 mass%. When the amount of pigment or dye added is less than 0.01% by mass, the sensitivity tends to be low. When the amount exceeds 50% by mass, the uniformity of the recording layer increases as the blending amount increases. There is a risk of adversely affecting durability. In addition, the dye or pigment used may be a single compound or a mixture of two or more compounds, and dyes or pigments having different absorption wavelengths are used in combination in order to cope with an exposure machine having a plurality of wavelengths. It is also preferably done.

[Other ingredients]
In forming the positive image forming layer in the present invention, various additives can be further added as necessary. For example, it is thermally decomposable, such as other onium salts, o-quinonediazide compounds, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, etc., and substantially reduces the solubility of the alkaline water-soluble polymer compound in a state where it does not decompose. Use of a substance in combination is preferable from the viewpoint of improving the dissolution inhibiting property of the image area in the developer. Examples of other onium salts include oniums other than sulfonium salts represented by the general formula (II), such as diazonium salts, ammonium salts, phosphonium salts, iodonium salts, selenonium salts, arsonium salts, azinium salts, and the like. be able to.

As other onium salts used in the present invention, for example, S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T .; S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056, phosphonium salts described in J. Pat. V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, U.S. Pat. Nos. 5,041,358 and 4,491,628, JP-A-2-150848, JP-A-2-296514. Iodonium salts described in each of the above publications; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J. MoI. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), C.I. S. Wen et al, Theh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).
Of the other onium salts, diazonium salts are particularly preferred. Particularly suitable diazonium salts include those described in JP-A-5-158230.

  Counter ions in the other onium salts include tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, and 2,5-dimethylbenzene. Sulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol- Examples include 5-sulfonic acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and paratoluenesulfonic acid. Of these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide helps the solubility of the sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder due to thermal decomposition and the change of o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include J. Although the compounds described in pages 339 to 352 of “Light-Sensitive Systems” (John Wiley & Sons. Inc.) by Korser can be used, they are particularly reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. Preferred are sulfonic acid esters or sulfonic acid amides of quinonediazides. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride and pyrogallol-acetone resin as described in JP-B-43-28403 Esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide- described in U.S. Pat. Nos. 3,046,120 and 3,188,210. Esters of 5-sulfonic acid chloride and phenol-formaldehyde resin are also preferably used.

  Further, esters of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride with phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17482, U.S. Pat. Nos. 2,797,213, 3,454,400, and 3,544 No. 323, No. 3,573,917, No. 3,674,495, No. 3,785,825, British Patent No. 1,227,602, No. 1,251,345, No. No. 1,267,005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890 and the like. .

  The addition amount of the o-quinonediazide compound is preferably in the range of 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass with respect to the total solid content of the image forming material. These compounds can be used alone, but may be used as a mixture of several kinds.

  The addition amount of additives other than the o-quinonediazide compound is preferably 1 to 50% by mass, more preferably 5 to 30% by mass, and particularly preferably 10 to 30% by mass with respect to the total solid content of the image forming material. is there. In addition, it is preferable to make the additive and binder in this invention contain in the same layer.

  Further, for the purpose of further improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in combination. Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride described in US Pat. No. 4,115,128, Tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. As phenols, bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 ″ -Trihydroxytriphenylmethane, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane and the like. There are sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric acid esters, carboxylic acids, and the like, which are described in Japanese Laid-Open Patent Publication No. 60-88942 and Japanese Patent Application Laid-Open No. 2-96755. , P-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate Phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1, Examples thereof include 2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid, etc. The ratio of the cyclic acid anhydride, phenols and organic acids in the image forming material is 0.05-20. % By mass is preferable, more preferably 0.1 to 15% by mass, and particularly preferably 0.1 to 10% by mass.

Further, in the image forming layer coating solution in the present invention, in order to broaden the stability of the processing with respect to the developing conditions, nonionic ions such as those described in JP-A Nos. 62-251740 and 3-208514 are disclosed. Surfactants, amphoteric surfactants as described in JP-A-59-121044, JP-A-4-13149, siloxane compounds as described in EP950517, JP-A-11-288093 Fluorine-containing monomer copolymers such as those described in the publication can be added.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Co., Ltd.).
The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-732, DBP-534, manufactured by Chisso Corporation. And polyalkylene oxide-modified silicones such as Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and the amphoteric surfactant in the image forming material is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

In the image forming layer of the present invention, a print-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, 36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole compounds and triazine compounds, both of which have excellent temporal stability and give clear printout images.

  As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, oil yellow # 101, oil yellow # 103, oil pink # 312, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added to the image forming material in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the image forming material. Furthermore, a plasticizer is added to the image forming material of the present invention as needed in order to impart flexibility of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.

  In addition to these, epoxy compounds, vinyl ethers, and further, phenol compounds having a hydroxymethyl group, phenol compounds having an alkoxymethyl group, and the present inventors described in JP-A-8-276558, A crosslinkable compound having an alkali dissolution inhibiting action described in JP-A-11-160860 proposed in JP-A-11-160860 can be appropriately added depending on the purpose.

  The image forming material of the present invention is formed by forming this image forming layer on a suitable support, and can be applied to various uses such as a lithographic printing plate precursor, a color proof, and a display material. Heat capable of direct plate making by laser exposure is also useful as a lithographic printing plate precursor corresponding to the degree.

[Lithographic printing plate precursor]
Specific embodiments will be described below by giving an example in which the image forming material of the present invention is applied to a lithographic printing plate precursor.

(Image forming layer)
The lithographic printing plate precursor to which the image forming material of the present invention is applied can be produced by dissolving the photosensitive layer (image forming layer) coating solution component in a solvent and coating the solution on a suitable support. Further, depending on the purpose, a protective layer, a resin intermediate layer, a backcoat layer, and the like can be formed in the same manner.
Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited. These solvents are used alone or in combination.
The concentration of the above components (total solid content including additives) in the solvent is preferably 1 to 50% by mass.

The coating amount (solid content) on the support obtained after coating and drying varies depending on the use, but generally speaking, 0.5 to 5.0 g / m ² for the image forming layer of the lithographic printing plate precursor. Is preferred. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the image forming layer decrease.
Further, the image forming layer may be a single layer or may have a multilayer structure.

Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
In the image forming layer of the present invention, a surfactant for improving the coating property, for example, a fluorosurfactant described in JP-A-62-170950 can be added. A preferable addition amount is 0.01 to 1% by mass, and more preferably 0.05 to 0.5% by mass in the total solid content of the image forming layer.

(Resin intermediate layer)
The lithographic printing plate precursor can be provided with a resin intermediate layer between the image forming layer and the support, if necessary.
By providing this resin intermediate layer, an image-forming layer, which is an infrared-sensitive layer whose solubility in an alkaline developer is improved by exposure, is provided on the exposed surface or in the vicinity thereof, and the sensitivity to the infrared laser is good. In addition, there is a resin intermediate layer made of a polymer between the support and the infrared sensitive layer, which functions as a heat insulating layer, and the heat generated by the infrared laser exposure is not diffused to the support, so that an image can be formed efficiently. Since it is used, there is an advantage that high sensitivity can be achieved. In the unexposed area, the image forming layer itself that is impermeable to the alkali developer functions as a protective layer for the resin intermediate layer, so that the development stability is improved and the discrimination is excellent. It is considered that an image is formed and stability over time is ensured, and in the exposed portion, the components of the image forming layer whose dissolution inhibiting ability is released are quickly dissolved and dispersed in the developer. Since the resin intermediate layer itself adjacent to the support is made of an alkali-soluble polymer, the solubility in a developer is good, for example, even when a developer with reduced activity is used. It is considered that this resin intermediate layer is useful because it dissolves quickly without generating a residual film and contributes to improvement of developability.

[Support]
The support used in the present invention is a dimensionally stable plate, for example, paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), metal plate (for example, aluminum). , Zinc, copper, etc.), plastic films (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), Examples include paper or plastic film on which a metal as described above is laminated or vapor-deposited.
The support according to the present invention is preferably a polyester film or an aluminum plate, particularly when used for a lithographic printing plate precursor. Among them, an aluminum plate is particularly preferable because of its good dimensional stability and relatively low cost. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of different elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is at most 10% by mass. Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

  Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used. The roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment as necessary, and then subjected to anodization treatment if desired in order to enhance the water retention and wear resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. When the amount of the anodized film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image portion of the planographic printing plate is easily damaged, and the ink adheres to the damaged portion during printing. So-called “scratch stains” easily occur. After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. Examples of the hydrophilization treatment used in the present invention include U.S. Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902. There is an alkali metal silicate (eg, aqueous sodium silicate) method as disclosed in US Pat. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and U.S. Pat. Nos. 3,276,868, 4,153,461, 4,689, A method of treating with polyvinylphosphonic acid as disclosed in the specification of No. 272 is used.

The lithographic printing plate precursor to which the present invention is applied has a positive type image forming layer provided on a support, and an undercoat layer can be provided between them if necessary.
As an undercoat layer component, various organic compounds are used. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphone which may have a substituent. Acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, organic phosphonic acid such as methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphonic acid, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid optionally having substituents Of organic phosphoric acid such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and triethanolamine which may have a substituent Hydroxy groups such as hydrochloride Selected from hydrochloride of the amine to be, but may be used by mixing two or more.

This organic undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is dissolved and applied on an aluminum plate and dried, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution obtained by dissolving the above organic compound in an organic solvent or a mixed solvent thereof to adsorb the above compound, and then washed with water and dried to provide an organic undercoat layer. . In the former method, a solution having a concentration of 0.005 to 10% by mass of the organic compound can be applied by various methods.
In the latter method, the concentration of the solution is 0.01 to 20% by mass, preferably 0.05 to 5% by mass, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., and the immersion time. Is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image recording material.
The coating amount of the organic undercoat layer is suitably ² to 200 mg / m ² , preferably 5 to 100 mg / m ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. Moreover, even if it is larger than 200 mg / m ^2, it is the same.

[Exposure / Development]
The positive lithographic printing plate precursor produced as described above is usually subjected to image exposure and development processing.
As the light source of the light beam used for image exposure, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser or a semiconductor laser is particularly preferable.
Since the image forming material of the present invention is excellent in shrinkage, the development property is not lowered even when the lithographic printing plate precursor to which the image forming material is applied is not developed immediately after exposure and developed after a predetermined time. Absent. For this reason, for example, it is suitable when a plurality of lithographic printing plate precursors that have been exposed are stocked and then processed together by an automatic developing machine. Excellent developability.

As a developer and a replenisher for a lithographic printing plate precursor to which the present invention is applied, a conventionally known alkaline aqueous solution can be used.
For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium, and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are also used. These alkali agents are used alone or in combination of two or more.
Among these alkali agents, particularly preferred developers are aqueous silicate solutions such as sodium silicate and potassium silicate. This is because the developability can be adjusted by the ratio and concentration of silicon oxide SiO ₂ and alkali metal oxide M ₂ O, which are silicate components. For example, Japanese Patent Laid-Open No. 54-62004 An alkali metal silicate as described in JP-B-57-7427 is effectively used.

  Furthermore, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer so that the developer in the developer tank is not changed for a long time. It is known that lithographic printing plate precursors can be processed. This replenishment method is also preferably applied in the present invention.

Various surfactants and organic solvents can be added to the developer and replenisher as necessary for the purpose of promoting and suppressing developability, dispersing development residue, and improving ink affinity of the printing plate image area.
Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. If necessary, the developer and replenisher may contain reducing agents such as hydroquinone, resorcin, sulfurous acid, bisulfite, and other inorganic acids such as sodium salts and potassium salts, organic carboxylic acids, antifoaming agents, and hard water softeners. It can also be added.
The printing plate developed using the developer and the replenisher is post-treated with water-washing water, a rinsing solution containing a surfactant and the like, a desensitizing solution containing gum arabic and starch derivatives. As the post-treatment when the image recording material of the present invention is used as a printing plate, these treatments can be used in various combinations.

  In recent years, automatic developing machines for printing plates have been widely used in the plate making and printing industries in order to rationalize and standardize plate making operations. This automatic developing machine is generally composed of a developing unit and a post-processing unit, and includes an apparatus for transporting the printing plate, each processing liquid tank and a spray device, and each pumped up by a pump while transporting the exposed printing plate horizontally. The processing liquid is sprayed from the spray nozzle and developed. In addition, recently, a method is also known in which a printing plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid. In such automatic processing, each processing solution can be processed while being supplemented with a replenisher according to the processing amount, operating time, and the like. In addition, a so-called disposable processing method in which processing is performed with a substantially unused processing solution is also applicable.

  In the present invention, when there is an unnecessary image portion (for example, a film edge mark of the original film) on the lithographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming. The unnecessary image portion is erased. Such erasing is preferably performed by applying an erasing solution to an unnecessary image portion as described in Japanese Patent Publication No. 2-13293, leaving it for a predetermined time, and then washing with water. A method of developing after irradiating an unnecessary image portion with an actinic ray guided by an optical fiber as described in JP-A-59-174842 can also be used.

The lithographic printing plate obtained as described above can be subjected to a printing process after applying a desensitized gum if desired. However, if it is desired to obtain a lithographic printing plate with higher printing durability, Processing is performed. In the case of burning a lithographic printing plate, before burning, an adjustment as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. It is preferable to treat with a surface liquid.
As its method, with a sponge or absorbent cotton soaked with the surface-adjusting liquid, it is applied onto a lithographic printing plate, or a method in which the printing plate is immersed and applied in a vat filled with the surface-adjusting liquid, Application by an automatic coater is applied. Further, it is more preferable to make the coating amount uniform with a squeegee or a squeegee roller after coating.

In general, the amount of surface-adjusting solution applied is suitably 0.03 to 0.8 g / m ² (dry mass). The lithographic printing plate coated with the surface-adjusting liquid is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). Is done. In this case, the heating temperature and time are in the range of 180 to 300 ° C. and preferably in the range of 1 to 20 minutes, although depending on the type of components forming the image.

  The lithographic printing plate that has been burned can be subjected to conventional treatments such as washing and gumming as needed, but a surface-conditioning solution containing a water-soluble polymer compound is used. In such a case, a so-called desensitizing treatment such as gumming can be omitted. The planographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

(Production of support)
Supports A, B, C, and D were prepared by using a JIS-A-1050 aluminum plate having a thickness of 0.3 mm in combination with the following processes.

(A) Mechanical surface roughening treatment While supplying a suspension of abrasive (silica sand) having a specific gravity of 1.12 and water as a polishing slurry liquid to a surface of an aluminum plate, it is mechanically rotated by a roller-like nylon brush. Roughening was performed. The average particle size of the abrasive was 8 μm, and the maximum particle size was 50 μm. The material of the nylon brush was 6 · 10 nylon, the hair length was 50 mm, and the hair diameter was 0.3 mm. The nylon brush was planted so as to be dense by making a hole in a stainless steel tube having a diameter of 300 mm. Three rotating brushes were used. The distance between the two support rollers (φ200 mm) at the bottom of the brush was 300 mm. The brush roller was pressed until the load of the drive motor for rotating the brush became 7 kW plus with respect to the load before the brush roller was pressed against the aluminum plate. The rotating direction of the brush was the same as the moving direction of the aluminum plate. The rotation speed of the brush was 200 rpm.

(B) Alkali etching treatment The aluminum plate obtained above was sprayed with an aqueous NaOH solution at a temperature of 70 ° C. (concentration 26 mass%, aluminum ion concentration 6.5 mass%) to perform an etching treatment, and the aluminum plate was 6 g / m. ² dissolved. Thereafter, washing with water was performed using well water.

(C) Desmutting treatment The desmutting treatment was performed by spraying with a 1% by mass aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), and then washed with water by spraying. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(D) Electrochemical roughening treatment An electrochemical roughening treatment was carried out continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a nitric acid 10.5 g / liter aqueous solution (aluminum ion 5 g / liter) at a temperature of 50 ° C. The AC power supply waveform has an electrochemical surface roughening treatment using a carbon electrode as a counter electrode using a trapezoidal rectangular wave alternating current with a time TP of 0.8 msec until the current value reaches a peak from zero, a DUTY ratio of 1: 1. went. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 30 A / dm ² at the peak current value, and the amount of electricity was 220 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode. 5% of the current flowing from the power source was shunted to the auxiliary anode.
Thereafter, washing with water was performed using well water.

(E) Alkali etching treatment The aluminum plate was sprayed at a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass at 32 ° C. to dissolve the aluminum plate by 0.20 g / m ² , The smut component mainly composed of aluminum hydroxide generated when electrochemical surface roughening was used was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(F) Desmut treatment Desmut treatment was performed by spraying with a 15% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 4.5% by weight of aluminum ions), and then washed with water using well water. The nitric acid aqueous solution used for the desmut was the waste liquid from the step of electrochemical surface roughening using alternating current in nitric acid aqueous solution.

(G) Electrochemical surface roughening treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type.
The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 50 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Thereafter, washing with water was performed using well water.

(H) Alkaline etching treatment An aluminum plate is etched by spraying at 32 ° C. with a caustic soda concentration of 26% by mass and an aluminum ion concentration of 6.5% by mass, and the aluminum plate is dissolved at 0.10 g / m ² , so The smut component mainly composed of aluminum hydroxide generated during the electrochemical surface roughening treatment was removed, and the edge portion of the generated pit was melted to smooth the edge portion. Thereafter, washing with water was performed using well water.

(I) Desmut treatment A desmut treatment by spraying was performed with a 25% by mass aqueous solution of sulfuric acid having a temperature of 60 ° C. (containing 0.5% by mass of aluminum ions), and then water washing by spraying was performed using well water.

(J) Anodizing treatment As the electrolytic solution, sulfuric acid was used. All electrolytes had a sulfuric acid concentration of 170 g / liter (containing 0.5 mass% of aluminum ions), and the temperature was 43 ° C. Thereafter, washing with water was performed using well water.
Both current densities were about 30 A / dm ² . The final oxide film amount was 2.7 g / m ² .

<Support A>
The steps (a) to (j) were performed in order, and the support was prepared so that the etching amount in the step (e) was 3.4 g / m ² .

<Support B>
Except for omitting the steps (g), (h) and (i) among the above steps, each step was performed in order to prepare a support.

<Support C>
A support was prepared by sequentially performing each step except that the steps (a), (g), (h), and (i) were omitted.

<Support D>
Except for omitting the process of the above step (a) and (d) (e) (f ) performs the steps in turn, supported as total amount of electricity is 450C / dm ² in step (g) The body was made.

  Supports A, B, C, and D obtained as described above were subsequently subjected to the following hydrophilization treatment and undercoating treatment.

(K) Alkali metal silicate treatment Alkali metal silicate is obtained by immersing the aluminum support obtained by the anodizing treatment in a treatment layer of No. 3 sodium silicate 1 mass% aqueous solution at a temperature of 30 ° C. for 10 seconds. Salt treatment (silicate treatment) was performed. Then, the water washing by the spray using well water was performed. The amount of silicate adhering at that time was 3.6 mg / m ² .

(Undercoating)
On the aluminum support after the alkali metal silicate treatment obtained as described above, an undercoat solution having the following composition was applied and dried at 80 ° C. for 15 seconds. The coating amount after drying was 16 mg / m ² .

<Undercoat liquid composition>
・ The following polymer compound 0.3g
・ Methanol 100g
・ Water 1.0g

[Examples 1-8, Comparative Examples 1-2]
A coating solution for the first layer (lower layer) having the following composition was applied to the obtained support A with a wire bar, and then dried in a drying oven at 150 ° C. for 60 seconds to obtain a coating amount of 0.85 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was carried out at 145 ° C. for 70 seconds in a drying oven, and positive lithographic printing plate precursors of Examples 1 to 8 and Comparative Examples 1 and 2 were prepared with a total coating amount of 1.15 g / m ² .

<First layer (lower layer) coating solution>
-Copolymer 1 (synthesized by the following) 2.133 g
・ Cyanine dye A (the following structure) 0.098g
・ 2-Mercapto-5-methylthio-
1,3,4-thiadiazole 0.030 g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.100 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
・ 0.100 g of counter anion of ethyl violet
What changed to 6-hydroxynaphthalenesulfonic acid ・ 3-methoxy-4-diazodiphenylamine 0.030 g
Hexafluorophosphate / fluorine surfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Γ-Butyrolactone 13.8g

<Synthesis of Copolymer 1>
After stirring, 31.0 g (0.36 mol) of methacrylic acid, 39.1 g (0.36 mol) of ethyl chloroformate and 200 ml of acetonitrile were placed in a 500 ml three-necked flask equipped with a condenser and a dropping funnel, and cooled in an ice-water bath. The mixture was stirred while. To this mixture, 36.4 g (0.36 mol) of triethylamine was dropped with a dropping funnel over about 1 hour. After completion of the dropwise addition, the ice-water bath was removed, and the mixture was stirred at room temperature for 30 minutes.

  To this reaction mixture, 51.7 g (0.30 mol) of p-aminobenzenesulfonamide was added, and the mixture was stirred for 1 hour while warming to 70 ° C. in an oil bath. After completion of the reaction, the mixture was added to 1 liter of water with stirring, and the resulting mixture was stirred for 30 minutes. The mixture was filtered to take out a precipitate, which was slurried with 500 ml of water, then the slurry was filtered, and the obtained solid was dried to dry a white solid of N- (p-aminosulfonylphenyl) methacrylamide. Was obtained (yield 46.9 g).

  Next, 4.61 g (0.0192 mol) of N- (p-aminosulfonylphenyl) methacrylamide and 2.58 g of ethyl methacrylate (0.0258 mol) were added to a 20 ml three-necked flask equipped with a stirrer, a condenser and a dropping funnel. ), 0.80 g (0.015 mol) of acrylonitrile and 20 g of N, N-dimethylacetamide were added, and the mixture was stirred while heating to 65 ° C. with a hot water bath. To this mixture, 0.15 g of 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name: “V-65”, manufactured by Wako Pure Chemical Industries, Ltd.) was added as a polymerization initiator and maintained at 65 ° C. The mixture was stirred for 2 hours under a nitrogen stream. This reaction mixture was further mixed with 4.61 g of N- (p-aminosulfonylphenyl) methacrylamide, 2.58 g of methyl methacrylate, 0.80 g of acrylonitrile, 20 g of N, N-dimethylacetamide and 0.15 g of “V-65”. Was dropped by a dropping funnel over 2 hours. After completion of the dropwise addition, the resulting mixture was further stirred at 65 ° C. for 2 hours. After completion of the reaction, 40 g of methanol was added to the mixture, cooled, and the resulting mixture was poured into 2 liters of water while stirring the water. After stirring the mixture for 30 minutes, the precipitate was removed by filtration and dried. 15 g of a white solid was obtained. It was 54,000 when the weight average molecular weight (polystyrene standard) of this specific copolymer 1 was measured by the gel permeation chromatography.

<Second layer (upper layer) coating solution>
-Ethyl methacrylate and 2-methacryloyloxyethyl succinic acid 0.030 g
Copolymer (molar ratio 67:33, weight average molecular weight 92,000)
・ Specific novolak resin (compound described in Table 1) 0.300 g
・ Sulphonium salt (compound described in Table 1) 0.1 g
・ Cyanine dye A (the above structure) 0.015 g
・ 0.012g of counter anion of ethyl violet
What changed to 6-hydroxynaphthalenesulfonic acid ・ Fluorosurfactant 0.022g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g

[Evaluation of lithographic printing plate precursor]
The evaluation of the lithographic printing plate precursor was conducted for each of the development latitude, sensitivity, and shrinkability. Details of the evaluation method are as follows.

1. Development Latitude A lithographic printing plate precursor is stored for 5 days under conditions of a temperature of 25 ° C. and a relative humidity of 50%. I did.
Thereafter, a PS processor 900H manufactured by Fuji Photo Film Co., Ltd. was used, in which the electric conductivity was changed by changing the mass ratio of water in the alkaline developer of the following A composition and B composition. The liquid temperature was kept at 30 ° C., and development was performed with a development time of 22 seconds. At this time, the developer having the highest conductivity and the lowest conductivity of the developer in which the image portion was not eluted and the development was successfully performed without contamination and coloring caused by the poorly developed photosensitive layer residual film. The difference was evaluated as development latitude.

<Alkali developer A composition>
・ SiO ₂ · K ₂ O (K ₂ O / SiO ₂ = 1/1 (molar ratio)) 4.0% by mass
・ Citric acid 0.5% by mass
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 95.0 mass%
<Alkali developer B composition>
・ D sorbit 2.5% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether 0.5% by mass
(Weight average molecular weight 1,000)
・ Water 96.15% by mass

2. Sensitivity A test pattern was drawn on the lithographic printing plate by changing the exposure energy with a Trendsetter 3244 VX manufactured by Creo.
Thereafter, in the evaluation of the development latitude, the image portion is not eluted, and the developer having the highest electrical conductivity of the developer that can be satisfactorily developed without being stained or colored due to a poorly developed photosensitive layer residual film; Developed with an alkaline developer having an intermediate (average) conductivity with the lowest one, and measured the exposure amount (beam intensity at a drum rotation speed of 130 rpm) that can develop a non-image area with this developer. It was. The smaller the numerical value, the higher the sensitivity.

3. After exposure, after storage for 1 hour in an environment at 25 ° C. and a relative humidity of 70%, the same evaluation as the sensitivity evaluation was performed, and the degree of decrease in sensitivity immediately after the exposure was used as a guideline for the storage characteristics. The numerical value represents the sensitivity after 1 hour of exposure, and the closer the numerical value is to the sensitivity immediately after the exposure, the better the shrinkage.

<Evaluation of planographic printing plate precursors of Example 1 and Comparative Examples 1 and 2>
Each planographic printing plate precursor of Example 1及 beauty Comparative Examples 1-2, development latitude, sensitivity, and baked sump property was evaluated by the method described above. Developer B was used as the developer. The results are shown in Table 1.

The details of (A) specific novolak resins (P1, P2) and novolak resin (C1) outside the scope of the present invention described in Table 1 below are as shown below.
Novolac resin P1: phenolcresol-formaldehyde novolac
(Phenol: m-cresol: p-cresol = 30: 30: 40,
(Weight average molecular weight: 5500)
Novolac resin P2: phenol cresol-formaldehyde novolac
(Phenol: m-cresol: p-cresol = 60: 30: 10,
Weight average molecular weight: 7700)
Novolak resin C1: Cresol-formaldehyde novolak (m-cresol: p-cresol = 60: 40, weight average molecular weight: 5000)

  In Comparative Example 2, ammonium compound A (ammonium A) shown below was added instead of the sulfonium salt.

As shown in Table 1, it can be seen that the lithographic printing plate precursor of Example 1 achieves improved printing quality while maintaining development latitude and sensitivity. On the other hand, in both Comparative Example 1 using a novolak resin containing no phenol as a structural unit in place of the specific novolak resin of the present invention and Comparative Example 2 using an ammonium salt in place of the sulfonium salt, development latitude and print-out property are improved. However, it was inferior to the Example.

(Examples 9-16, Comparative Examples 3-4)
A coating solution for the first layer (lower layer) having the following composition was applied to the obtained support C with a wire bar, and then dried in a drying oven at 130 ° C. for 60 seconds to obtain a coating amount of 0.60 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 150 ° C. for 60 seconds in a drying oven, and positive lithographic printing plate precursors of Examples 9 to 16 and Comparative Examples 3 to 4 were prepared with a total coating amount of 1.25 g / m ² .

<First layer (lower layer) coating solution>
・ Copolymer 1 2.133 g
・ Cyanine dye A (the above structure) 0.098 g
・ 2-Mercapto-5-methylthio
-1,3,4-thiadiazole 0.030 g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.100 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
・ 0.100 g of counter anion of ethyl violet
What changed to 6-hydroxynaphthalenesulfonic acid ・ 3-methoxy-4-diazodiphenylamine 0.030 g
Hexafluorophosphate / fluorine surfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Dimethylsulfoxide 13.8g

<Second layer (upper layer) coating solution>
-Ethyl methacrylate and 2-methacryloyloxyethyl succinic acid 0.030 g
Copolymer (molar ratio 67:33, weight average molecular weight 92,000)
・ Novolak resin (compound described in Table 2) 0.300 g
・ Sulphonium salt (compound described in Table 2) 0.016 g
・ Cyanine dye A (the above structure) 0.015 g
・ Fluorine surfactant 0.022g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g

<Evaluation of Examples 2-3 and Comparative Examples 3-4>
The obtained planographic printing plate precursors of Examples 2 to 3 and Comparative Examples 3 to 4 were evaluated in the same manner as in Example 1. Developer B was used as the developer. The results are shown in Table 2.
The details of (A) the specific novolak resin (P 3) shown in the following Table 2 is as shown below.
Novolac resin P3: phenol cresol-formaldehyde novolac
(Phenol: m-cresol: p-cresol = 40: 40: 20,
Weight average molecular weight: 5200 )
The novolak resin C1 used in Comparative Example 3 is the same as that used in Comparative Example 1, and the ammonium compound A (ammonium A) used in place of the sulfonium salt in Comparative Example 4 is the same as that used in Comparative Example 2. It is the same.

As shown in Table 2, it can be seen that the samples of the examples achieve improvement in the shrinkage while maintaining the development latitude and sensitivity. On the other hand, Comparative Examples 3 and 4 to which the specific novolak resin or the sulfonium salt according to the present invention was not added were inferior in development latitude and shrinkage.
Examples 2-3, Comparative Examples 3 and 4 Example 1, in comparison with the Comparative Examples 1 and 2, even when the image forming layer is a multilayer, excellent effects are obtained in the case of a single layer similarly to the present invention I found out that Further, by using the image forming layer as a multilayer, further improvement in sensitivity and development latitude was observed.

(Examples 4-7 , Comparative Examples 5-6)
A coating solution for the first layer (lower layer) having the following composition was applied to the obtained support D with a wire bar, and then dried in a drying oven at 150 ° C. for 60 seconds to obtain a coating amount of 0.81 g / m ² . did.
A coating solution for the second layer (upper layer) having the following composition was applied to the obtained support with a lower layer with a wire bar. After coating, drying was performed at 150 ° C. for 60 seconds in a drying oven, and positive lithographic printing plate precursors of Examples 4 to 7 and Comparative Examples 5 to 6 were prepared with a total coating amount of 0.99 g / m ² .

<First layer (lower layer) coating solution>
-Copolymer 1 2.133 g
・ Cyanine dye A (the above structure) 0.098 g
・ Cis-Δ ⁴ -tetrahydrophthalic anhydride 0.110 g
・ 4,4'-sulfonyldiphenol 0.090g
・ 0.008 g of p-toluenesulfonic acid
・ 0.100 g of counter anion of ethyl violet
What changed to 6-hydroxynaphthalenesulfonic acid ・ 3-methoxy-4-diazodiphenylamine 0.030 g
Hexafluorophosphate / fluorine surfactant 0.035g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 26.6g
1-methoxy-2-propanol 13.6 g
・ Γ-Butyrolactone 13.8g

<Second layer (upper layer) coating solution>
-Ethyl methacrylate and 2-methacryloyloxyethyl succinic acid 0.030 g
Copolymer (molar ratio 67:33, weight average molecular weight 92,000)
・ Novolak resin (compound described in Table 3) 0.300 g
・ Sulphonium salt (compound described in Table 3) 0.020 g
・ Cyanine dye A (the above structure) 0.015 g
・ Fluorine surfactant 0.022g
(Megafuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 13.1g
1-methoxy-2-propanol 6.79g

<Evaluation of Examples 4 to 7 and Comparative Examples 5 to 6>
The obtained lithographic printing plate precursor was evaluated by the method described above. Developer A was used as the developer. The results are shown in Table 3.
The details of (A) specific novolak resins (P5, P6) and novolak resin (C2) outside the scope of the present invention described in Table 3 below are as shown below.
Novolak resin P5: phenol cresol-formaldehyde novolak
(Phenol: m-cresol: p-cresol = 40: 40: 20,
Weight average molecular weight: 8000)
Novolak resin P 6 : phenol cresol-formaldehyde novolak
(Phenol: m-cresol: p-cresol = 60: 30: 10,
Weight average molecular weight: 7700)
Novolak resin C2: Cresol-formaldehyde novolak (m-cresol: p-cresol = 70: 30, weight average molecular weight: 10,000)

  In Comparative Example 6, ammonium compound B (ammonium B) shown below was used in place of the sulfonium salt.

As shown in Table 3, it can be seen that the lithographic printing plate precursors of Examples 4 to 7 achieve improvement in the shrinkage while maintaining the development latitude and sensitivity. On the other hand, it can be seen that the comparative nos. 5 and 6 to which the specific novolak resin or the sulfonium salt according to the present invention was not added are extremely inferior in shrinkage.

(Examples 8 to 10 , Comparative Examples 7 to 8)
The following image forming layer coating solution was applied to the obtained support D, dried at 150 ° C. for 1 minute to form an image forming layer, and the planographic printing plate precursors of Examples 8 to 10 and Comparative Examples 7 to 8 Got. The coating amount after drying was 1.55 g / m ² .

<Image forming layer coating solution>
・ Novolak resin (compound described in Table 4) 1.0 g
・ Sulphonium salt (compound described in Table 4) 0.05 g
・ Cyanine dye A (the above structure) 0.05 g
0.01 g of dye having 1-naphthalenesulfonic acid anion as the counter anion of Victoria Pure Blue BOH
・ Fluorosurfactant 0.05g
(Megafuck F-177, manufactured by Dainippon Ink & Chemicals, Inc.)
・ Methyl ethyl ketone 9.0g
・ 9.0 g of 1-methoxy-2-propanol

<Evaluation of Examples 8 to 10 and Comparative Examples 7 to 8>
The obtained lithographic printing plate precursors of Examples 8 to 10 and Comparative Examples 7 to 8 were evaluated in the same manner as in Example 1. Developer A was used as the developer. The results are shown in Table 4.
The details of (A) specific novolak resins (P7, P8) described in Table 4 below are as shown below.
Novolak resin P7: phenol cresol-formaldehyde novolak
(Phenol: m-cresol: p-cresol = 20: 60: 20,
(Weight average molecular weight: 10200)
Novolak resin P8: phenol xylenol-formaldehyde novolak (phenol: 2,5-xylenol = 60: 40, weight average molecular weight: 11000)
The novolak resin C2 used in Comparative Example 7 is the same as that used in Comparative Example 5, and the ammonium compound B (ammonium B) used in place of the sulfonium salt in Comparative Example 8 is the same as that used in Comparative Example 6. It is the same.

As shown in Table 4, it can be seen that the lithographic printing plate precursors of Examples 8 to 10 achieve improvement in the shrinkage while maintaining the development latitude and sensitivity. On the other hand, Comparative Examples 7 and 8 to which no specific novolak resin or sulfonium salt according to the present invention was added were inferior in development latitude and shrinkage.

Claims (2)

An image forming layer containing (A) a novolac type phenol resin containing phenol as a structural unit, (B) a photothermal conversion agent, and (C) a sulfonium salt represented by the following general formula (II) on a support. A positive-type image forming material.

In the general formula ^{(II), R 21, R} 22 and R ^23, rather it may also be the same as or different from each other, a halogen atom, a nitro group, having 12 or less carbon atoms alkyl group, having 12 or less carbon atoms And a hydrocarbon group having 20 or less carbon atoms having a substituent selected from an aryloxy group having 12 or less carbon atoms. (Z ²¹ ) ⁻ represents a residue of a sulfonic acid compound having pKa <5 or a residue of a carboxylic acid compound having pKa <5 . 2. The positive image forming material according to claim 1, wherein the sulfonium salt represented by the general formula (II) is a sulfonium salt represented by the following general formula (III).

In the above general formula (III), (Z ²¹ ) ⁻ represents a residue of a sulfonic acid compound in which pKa <5 or a residue of a carboxylic acid compound in which pKa <5 .