JP2006106058A - Lithographic printing original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive lithographic printing original plate for an infrared laser for direct plate making excellent in scuffing resistance and in discrimination of a formed image. <P>SOLUTION: The lithographic printing original plate has on a support two or more positive recording layers containing a resin and an infrared absorbent and having solubility in an alkaline aqueous solution increased by infrared laser exposure, wherein a positive recording layer closest to the support among the two or more positive recording layers contains at least two resins, at least one of which forms a dispersed phase, and contains a compound selected from the group consisting of naphthoquinone diazide, benzoquinone diazide and derivatives of those. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lithographic printing plate precursor, and more particularly to a positive lithographic printing plate precursor for infrared laser for so-called 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. In particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared can easily be obtained with high output and small size. These lasers are very useful as an exposure light source for making a plate directly from digital data such as a computer.
The positive type lithographic printing plate precursor for infrared laser has an alkaline aqueous solution-soluble binder resin and an infrared absorbing dye (IR dye) that absorbs light and generates heat as essential components. In the image area), it acts as a dissolution inhibitor that substantially lowers the solubility of the binder resin by interaction with the binder resin. In the exposed area (non-image area), the generated heat causes the IR dye and the binder resin to The interaction weakens and dissolves in an alkaline developer to form a lithographic printing plate.
However, in such a positive lithographic printing plate material for infrared laser, the solubility between the non-exposed area (image area) with respect to the developer and the solubility of the exposed area (non-image area) under various use conditions. However, there is a problem that over-development and poor development easily occur due to fluctuations in use conditions. In addition, even if the surface condition slightly changes due to touching the surface during handling, the unexposed area (image area) dissolves and becomes a scratch mark during development, causing deterioration in printing durability and poor inking properties. There was a problem.

Such a problem originates from the essential difference in the plate making mechanism between the positive lithographic printing plate material for infrared laser and the positive lithographic printing plate material made by UV exposure. That is, in a positive type lithographic printing plate material made by UV exposure, an alkaline aqueous solution-soluble binder resin and an onium salt or a quinonediazide compound are essential components. The onium salt or the quinonediazide compound is a non-exposed portion ( In addition to acting as a dissolution inhibitor by interacting with the binder resin in the image area), the exposed area (non-image area) plays two roles: it decomposes by light to generate acid and acts as a dissolution accelerator. Is.
On the other hand, IR dyes and the like in positive lithographic printing plate materials for infrared lasers only act as dissolution inhibitors for non-exposed areas (image areas), and do not promote dissolution of exposed areas (non-image areas). . Therefore, in the positive lithographic printing plate material for infrared laser, in order to make a difference in solubility between the non-exposed portion and the exposed portion, a binder resin having a high solubility in an alkaline developer must be used in advance. In other words, the state before development becomes unstable.

Various proposals have been made to solve the above problems. For example, there has been proposed a method of unevenly distributing an infrared absorber in a film in order to improve image discrimination (see, for example, Patent Document 1). However, it has not yet solved the problem of scratch resistance on the surface of the recording layer. Further, a lithographic printing plate precursor provided with a recording layer comprising a lower layer containing a sulfonamide acrylic resin and an upper layer containing a water-insoluble and alkali-soluble resin and a photothermal conversion agent and having increased solubility in an alkaline aqueous solution upon exposure. It has been proposed (see, for example, Patent Document 2). In this lithographic printing plate precursor, when the recording layer is removed in the exposed region, the lower layer excellent in alkali solubility is exposed, and the effect that an undesired residual film and the like are quickly removed by the alkali developer, The lower layer functions as a heat insulating layer, and the effect of effectively suppressing thermal diffusion to the support is exhibited. Furthermore, a method of imparting chemical resistance by blending a polymer in the lower layer has also been proposed (see, for example, Patent Document 3).
However, in order to form these multi-layer structures, it is necessary to select resins having different properties as the resins used in both layers, and there is a problem that their interactivity is lowered, or the developability of the lower layer is low. Due to the fact that it is good, there is a concern that undesired dissolution will occur at both ends of the lower layer in the image area during development, which may affect the printing durability and image reproducibility. There was still room for improvement to save.
JP 2001-281856 A JP 11-218914 A International Publication No. 01/46318 Pamphlet

  An object of the present invention is to provide a positive lithographic printing plate precursor for an infrared laser for direct plate making which is excellent in scratch resistance and formed image discrimination.

As a result of intensive research, the inventor has provided a positive recording layer having a multilayer structure, formed a dispersed phase of a plurality of resins in the recording layer closest to the support, and has a specific recording layer in the recording layer. It has been found that the above problems can be solved by containing a compound, and the present invention has been completed.
That is, the lithographic printing plate precursor according to the present invention includes a lithographic printing plate precursor having two or more positive recording layers containing a resin and an infrared absorber on a support and having increased solubility in an alkaline aqueous solution by infrared laser exposure. The positive recording layer closest to the support among the two or more positive recording layers contains at least two resins, and at least one of these resins forms a dispersed phase. And a compound selected from the group consisting of naphthoquinonediazide, benzoquinonediazide, and derivatives thereof (hereinafter, referred to as “specific compound” as appropriate).
The compound selected from the group consisting of the naphthoquinone diazide, benzoquinone diazide, and derivatives thereof is preferably contained in the dispersed phase.

Hereinafter, in this specification, the “positive recording layer closest to the support” is appropriately referred to as “lower layer” or “lower recording layer”.
The lithographic printing plate precursor according to the present invention may have other layers other than the plurality of positive recording layers, for example, a surface protective layer, an undercoat layer, an intermediate layer, a back coat layer, and the like on the support, if desired. It can be provided as long as the effects of the present invention are not impaired.

The dispersed phase in the present invention is a method of (1) using a combination of two resins that are incompatible with each other, or (2) dispersing a granular polymer selected from microcapsules and latex in a matrix resin. Can be formed.
Since the lithographic printing plate precursor according to the present invention uses a method that utilizes the change in solubility of the recording layer in alkaline water, the resin used in the positive recording layer is a water-insoluble and alkaline water-soluble resin. It is a preferable aspect to contain.
In the present invention, from the viewpoint of ease of production, the method (1) is preferably a method of forming a dispersed phase by combining two kinds of mutually incompatible resins. The two resins may be selected so that they are not compatible with each other, and even if they are uniformly dissolved in the coating solvent, a dispersed phase is formed with the removal of the solvent when the recording layer is formed. You may do.
Further, as such a lower recording layer, the resin that forms a matrix is composed of a polymer compound that is water-insoluble and soluble in an alkaline aqueous solution, and the dispersed phase is oxidized by irradiation with an infrared laser. A compound containing a radical generating compound or a resin forming a matrix is made of a polymer compound that is water-insoluble and soluble in an alkaline aqueous solution, and the dispersed phase is alkali-soluble when irradiated with an infrared laser. Those containing a compound in which is changed.
As the size of the dispersed phase, it is preferable that the maximum major axis is 0.1 to 0.8 μm and the average major axis is 0.05 to 0.6 μm. The size of the dispersed phase is the size of the circular or elliptical dispersed phase obtained by making the cross section of the photosensitive layer obtained by cutting the recording layer with a microtome or the like and then taking a photograph with a scanning electron microscope (SEM). Can be evaluated by an image analyzer.

In the present invention, the disperse phase in which the solubility in an aqueous alkali solution is increased by heat or light in the lower resin matrix phase increases the alkali solubility of the disperse phase in the exposed portion, and the Since the permeable path of the aqueous alkali solution is formed, the dissolution of the alkali-soluble resin matrix in the lower layer of the exposed area is promoted, and in the unexposed area (image area), the dispersed phase itself is soluble in an alkaline developer. Because it is low, the aqueous solution penetration into the underlying resin matrix phase, especially the penetration from the side, is effectively suppressed, so that damage in the alkaline aqueous solution in the image area can be suppressed, and image discrimination is excellent. It is presumed that a sharp image could be formed.
In addition, a compound (specific compound) selected from the group consisting of naphthoquinone diazide, benzoquinone diazide, and derivatives thereof, when unexposed, the naphthoquinone diazide compound acts as a lower layer dissolution inhibitor, while at the time of exposure, Since the specific compound is decomposed and this decomposition is irreversible, the solubility of the alkaline developer in the lower layer can be remarkably improved, and thus the dispersed phase in the lower layer and the effect exhibited by the specific compound are in phase. Therefore, it is presumed that the scratch resistance and the image discrimination can be improved more remarkably.

  The above-mentioned characteristics in the present invention are remarkable in a high-definition image having a small image area, and thus are particularly useful for a high-definition image such as an FM screen that has been used with the recent CTP. Therefore, the lithographic printing plate precursor of the present invention is a commercially available FM screen such as Staccato (trade name: manufactured by Creo), FAIRDOT, Randot (trade name: manufactured by Dainippon Screen), Co-Re screen (trade name: (Fuji Photo Film) and the like can be used suitably. Note that a high-definition image is one in which 50% area ratio output data is 210 lines or more in terms of perimeter.

  ADVANTAGE OF THE INVENTION According to this invention, the positive type lithographic printing plate precursor for infrared lasers for direct plate-making excellent in scratch resistance and the discrimination of the formed image can be provided. For this reason, according to the present invention, it is possible to improve the plate-making stability particularly in a high-definition image. Note that the high-definition image includes FM screen images that are increasingly used with the recent CTP conversion.

Hereinafter, the present invention will be described in detail.
The lithographic printing plate precursor according to the invention is a lithographic printing plate precursor comprising a resin and an infrared absorber on a support, and having two or more positive recording layers whose solubility in an alkaline aqueous solution is increased by infrared laser exposure. The positive recording layer closest to the support among the two or more positive recording layers contains at least two types of resins, and at least one of those resins forms a dispersed phase, And a compound selected from the group consisting of naphthoquinonediazide, benzoquinonediazide, and derivatives thereof.

[A compound selected from the group consisting of naphthoquinone diazide, benzoquinone diazide, and derivatives thereof]
In the present invention, the lower layer contains a compound (specific compound) selected from the group consisting of naphthoquinone diazide, benzoquinone diazide, and derivatives thereof as an essential component.
As the specific compound in the present invention, naphthoquinone diazide and the like known in the technical field of lithographic printing plate precursors are used, and examples thereof include [1] to [4] below, but are not limited thereto.

[1] The following o-naphthoquinonediazide derivative. That is, it has at least one o-naphthoquinonediazide group in the molecule, and becomes soluble in an alkaline solution when irradiated with active light. Such derivatives are described, for example, by Kosar, Light-Sensitive System, John Wiley & Sons Inc. , 1965, including those described in the art, such as esters or amides and a suitable aromatic polyhydroxy compound or amine. An example is 2-diazo-1,2-dihydro-1-oxonaphthalene sulfonic acid or esters of carboxylic acid chlorides. Specific examples include 2,4-bis (2-diazo-1,2-dihydro-1-oxo-5-naphthalenesulfonyloxy) benzophenone, 2-diazo-1,2-dihydro-1-oxo-5-naphthalene. Sulfonyloxy-2,2-bis (hydroxyphenyl) propane monoester, hexahydroxybenzophenone hexaester of 2-diazo-1,2-dihydro-1-oxo-5-naphthalenesulfonic acid, 2,2′-bis (2 -Diazo-1,2-dihydro-1-oxo-5-naphthalenesulfonyloxy) biphenyl, 2,2 ′, 4,4′-tetrakis (2-diazo-1,2-dihydro-1-oxo-5-naphthalene) Sulfonyloxy) biphenyl, 2,3,4-tris (2-diazo-1,2-dihydro-1-oxo-5-naphthalenesulfo Ruoxy) benzophenone, 2,4-bis (2-diazo-1,2-dihydro-1-oxo-4-naphthalenesulfonyloxy) benzophenone, 2-diazo-1,2-dihydro-1-oxo-4-naphthalenesulfonyl Oxy-2,2-bis (hydroxyphenyl) propane monoester, hexahydroxybenzophenone hexaester of 2-diazo-1,2-dihydro-1-oxo-4-naphthalenesulfonic acid, 2,2′-bis (2- Diazo-1,2-dihydro-1-oxo-4-naphthalenesulfonyloxy) biphenyl, 2,2 ′, 4,4′-tetrakis (2-diazo-1,2-dihydro-1-oxo-5-naphthalenesulfonyl) Oxy) biphenyl, 2,3,4-tris (2-diazo-1,2-dihydro-1-oxo-4-naphth Ren sulfonyloxy) benzophenone, and the like.

[2] A reaction product of the o-naphthoquinonediazide derivative exemplified in the above [1] and a resin. Here, as the resin to be reacted with the o-naphthoquinonediazide derivative, any resin having an appropriate reactive group for participating in such a reaction can be used. For example, such a resin includes a resin having a reactive hydroxy group or amino group.
As the resin, a phenol resin is most preferable. Examples of other resins other than phenolic resins include copolymers of acrylates and methacrylates and hydroxy-containing acrylates or methacrylates (for example, hydroxyethyl methacrylate and the like, as described in US Pat. No. 3,859,099). Copolymer of methyl methacrylate), copolymers of styrene (or styrene derivatives) and aminostyrene (eg, copolymers of styrene and p-aminostyrene, as described in US Pat. No. 3,759,711). ), Etc.

  There are many phenol resins that can be reacted with the o-naphthoquinonediazide derivative, either on the main chain of the resin or on the side chain (pendant group), which are stable to light, insoluble in water, and soluble in alkali. It is a film-forming resin having a hydroxy group. The phenolic resin used here usually has a molecular weight (measured by gel permeation chromatography) of at least 350, preferably at least 1000. The upper limit of the molecular weight is about 100,000. Further, the pKa value is usually not larger than 11 and has a low pKa value such as 7. Here, the phenol resin includes, but is not limited to, a novolak resin, a resole resin, and those known as polyvinyl compounds having a phenolic hydroxy group. Among these, novolak resin is preferable. Novolak resins are generally polymers produced by the condensation reaction of phenols and aldehydes, such as formaldehyde, or aldehyde releasing compounds capable of undergoing phenol-aldehyde condensation in the presence of an acid catalyst. Typical novolac resins include, but are not limited to, phenol-formaldehyde resins, cresol-formaldehyde resins, phenol-cresol-formaldehyde resins, pt-butylphenol-formaldehyde resins, and pyrogallol-acetone resins. is not. Such compounds are well known, for example, U.S. Pat. Nos. 4,308,368, 4,845,008, 5,437,952, 5,491,046, No. 5,143,816 and British Patent No. 1,546,633. Particularly useful novolac resins can be prepared by reacting m-cresol or phenol with formaldehyde under conventional conditions. Other useful phenolic resins include those known as “resole resins” which are condensation products of bisphenol A and formaldehyde. As such a resin, a commercially available product can be used, and examples thereof include UCAR phenol resin BKS-5928 (manufactured by Georgia Pacific Corporation). In addition, other useful phenolic resins are polyvinyl compounds having phenolic hydroxyl groups. Such compounds include, but are not limited to, polyhydroxystyrene and copolymers having hydroxystyrene repeat units, and polymers and copolymers having halogenated hydroxystyrene repeat units. Absent. Such polymers are described, for example, in US Pat. No. 4,845,008. Other hydroxy-containing polyvinyl compounds are described in US Pat. Nos. 4,306,010 and 4,306,011 and can be prepared by reacting a polyhydric alcohol with an aldehyde or ketone. Furthermore, the phenol resin described in US Pat. No. 5,368,977 is also suitable.

[3] US Pat. Nos. 2,766,118, 2,767,092, 2,772,972, 2,859,112, 2,907,665, 3,046,110, 3 , 046,111, 3,046,115, 3,046,118, 3,046,119, 3,046,120, 3,046,121, 3,046,122, 3, Naphthoquinonediazide compounds described in Nos. 036,123, 3,061,430, 3,102,809, 3,105,465, 3,635,709, and 3,647,443. Among these, preferred are o-naphthoquinone diazide sulfonate or o-naphthoquinone diazide carboxylate of an aromatic hydroxyl compound; o-naphthoquinone diazide sulfonic acid amide or o-naphthoquinone diazide carboxylic acid amide of an aromatic amine compound (for example, naphthoquinone). Ester of 1,2-diazide sulfonic acid and polyhydroxyphenyl); naphthoquinone-1,2-diazide-4-sulfonic acid or naphthoquinone-1,2-diazide-5-sulfonic acid and ester of pyrogallol / acetone resin; Naphthoquinone-1,2-diazidesulfonic acid and novolac phenol / formaldehyde resin or ester of novolac cresol / formaldehyde resin; poly (p-aminostyrene) and naphthoquinone-1,2-diazide Amides of 4-sulfonic acid or naphthoquinone-1,2-diazide-5-sulfonic acid; poly (p-hydroxystyrene) and naphthoquinone-1,2-diazido-4-sulfonic acid or naphthoquinone-1,2-diazide-5 -Esters of sulfonic acids; and amides of polymeric amines and naphthoquinone-1,2-diazide-4-sulfonic acids. The term “ester” as used herein also includes partial esters.

[4] A condensation product of a sulfonyl chloride of o-naphthoquinonediazide and a resin represented by the following general formula (i).

In formula (i), R ¹ represents an alkyl group having 1 to 8 carbon atoms. R ² represents a hydrogen atom, a halogen atom, a lower alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. R ³ represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, or a phenyl group. R ⁴ represents a hydrogen atom, a lower alkyl group having 1 to 4 carbon atoms, or a phenyl group.

  Details of the synthesis method of the condensation product of the sulfonyl chloride of o-naphthoquinonediazide and the resin represented by the above general formula (i), and the raw materials thereof are described in JP-A-56-1045. The same applies.

The specific compounds described above may be used alone or in combination of two or more. As content of the specific compound in a lower layer, 0.1-5.0 mass% is preferable, and 0.5-3.0 mass% is more preferable.
The specific compound in the present invention may be contained in any of the lower layer matrix (dispersion medium) and the dispersed phase, but is particularly preferably contained in the dispersed phase described later.

[Dispersed phase]
The lower layer in the present invention is characterized by forming a dispersed phase.
As described above, the dispersed phase in the present invention can be formed in the following manner. That is, (1) a mode in which a matrix (matrix phase), that is, a dispersion medium and a dispersion phase is formed using two or more kinds of resins (polymer compounds) that are not compatible with each other. In this case, the dispersion medium is used. A dispersed phase composed of a material that is incompatible with the material is formed. In another embodiment, (2) after forming a dispersed phase containing a predetermined component in advance using microcapsules or latex, the dispersed phase is introduced into a polymer binder, that is, a resin matrix phase. . In the dispersed phase, a dissolution inhibitor and an infrared absorber can be added as necessary.

Regarding the method for forming the dispersed phase, first, the dispersed phase obtained by the method (1) will be described. In the two or more kinds of polymer compounds that are not compatible with each other, at least one polymer compound is a polymer that is insoluble in water and soluble in an alkaline aqueous solution, and is preferably a polymer compound that forms a matrix phase. Here, incompatible with each other means that the combination of two or more polymers does not become a single-phase solid or liquid in appearance, and appropriately handles the cross section of the recording layer, It can be confirmed by taking and observing a cross-sectional photograph visually or with a scanning electron microscope.
Examples of polymer compounds used in combination of two or more kinds of incompatible polymer compounds include urethane polymer compounds, acrylic polymer compounds, styrene polymer compounds, novolac resins, diazo resins, and amide polymers. Examples thereof include a compound and a polyether compound.
Suitable combinations include acrylic polymer compounds and urethane polymer compounds, acrylic or urethane polymer compounds and diazo resins, novolak resins and urethane polymer compounds, and the like. Further, those containing a urethane polymer compound are preferred from the viewpoint of being hardly damaged during development.

When these two or more polymer compounds are used to form the lower recording layer in the presence of an infrared absorber, a dispersed phase is formed in the polymer binder, and the infrared absorber is contained in a large amount in the dispersed phase. Will be. When a binder layer is formed using two or more types of polymer compounds that are not compatible with each other, a polymer that exhibits stronger interaction such as hydrogen bonding and ionicity tends to form a spherical or flat sphere in the binder. Localization as described above indicates that when an infrared absorber is present in the dispersed phase, the infrared absorber is ionic or a coordination complex, so that the polymer compound having a strong interaction in the binder is used. This happens because it is easy to be taken in. When an acid generator or a radical generator (polymerization initiator) coexists, the initiator usually has a high polar group such as an onium salt structure, a triazine, a sulfonic acid ester, and the dispersed phase is similar to an infrared absorber. It is easy to be taken in.
Here, when the lower recording layer is formed using two or more kinds of polymer compounds that are incompatible with each other, when a dispersed phase is formed in the polymer matrix phase as a dispersion medium, this structure is called a sea-island structure. In the present invention, the observation of the sea-island structure is performed by making a recording layer cross-section obtained by cutting a lithographic printing plate precursor with a microtome or the like, and then taking a photograph with a scanning electron microscope (SEM). The size of the dispersed phase can be evaluated by an image analyzer. If the image is unclear when photographed, the cross section of the recording layer is processed by, for example, solvent etching according to the method described in “Polymer Alloy and Polymer Blend” (LA UTRACKI, translated by Toshio Nishi; Tokyo Chemical Dojin). After shooting, a clearer image can be obtained.

  In such a sea-island structure, the size of the dispersed phase present in the polymer binder phase serving as the dispersion matrix depends on the coating solvent system and the drying conditions after coating, but by controlling these conditions, Further, a dispersed phase having a maximum major axis of 0.8 μm or less, preferably 0.6 μm or less, and an average major axis of 0.6 μm or less, preferably 0.5 μm or less can be formed. In this case, it is preferable that the maximum major axis and the average major axis are small, and there are no particular limitations on these lower limits, but the maximum major axis is usually about 0.1 μm and the average major axis is about 0.05 μm. The major axis is obtained by image analysis of the dispersed phase particles as described above, and means a diameter when it is a circle and a major axis when it is an ellipse.

  When the specific compound is contained in the dispersed phase, the specific compound in the dispersed phase is detected by cutting the recording layer with a microtome, and then observing N in the dispersed phase by ESCA (X-ray photoelectron spectroscopy) from the cross section. This can be done by measuring the town.

  Hereinafter, other components in the lithographic printing plate precursor according to the invention will be described in detail sequentially. First, the positive recording layer will be described. The positive-type recording layer contains a water-insoluble and alkali-soluble polymer compound and a compound that suppresses alkali solubility, and the ability to suppress dissolution is eliminated by infrared laser exposure, thereby increasing the solubility in an alkali developer to form an image. To do.

[Alkali-soluble polymer]
In the present invention, a water-insoluble and alkali-soluble polymer compound (hereinafter referred to as an alkali-soluble polymer as appropriate) used for a plurality of positive recording layers is a main chain and / or a side chain in the polymer. Includes a homopolymer containing an acidic group, a copolymer thereof, or a mixture thereof. Therefore, the polymer layer according to the present invention has a property of dissolving when contacted with an alkaline developer.
The alkali-soluble polymer used in the lower recording layer and other recording layers (hereinafter, appropriately referred to as the upper recording layer) in the present invention is not particularly limited as long as it is a conventionally known polymer, but (1) phenolic It is preferably a polymer compound having a functional group of any one of a hydroxyl group, (2) a sulfonamide group, and (3) an active imide group in the molecule. For example, although the following are illustrated, it is not limited to these.

  (1) Examples of the polymer compound having a phenolic hydroxyl group include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p Any of-or m- / p-mixing) may be used. Examples thereof include novolak resins such as mixed formaldehyde resins and pyrogallol acetone resins. In addition to this, a polymer compound having a phenolic hydroxyl group in the side chain is preferably used as the polymer compound having a phenolic hydroxyl group. As a polymer compound having a phenolic hydroxyl group in the side chain, a polymerizable monomer comprising a low molecular compound having at least one unsaturated bond polymerizable with the phenolic hydroxyl group is homopolymerized, or other polymerizable property is added to the monomer. Examples thereof include a polymer compound obtained by copolymerizing monomers.

  Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene having a phenolic hydroxyl group. Specifically, N- (2-hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (2-hydroxyphenyl) methacrylamide, N- (3 -Hydroxyphenyl) methacrylamide, N- (4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate, m-hydroxyphenyl methacrylate, p- Hydroxyphenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) Preferred are ethyl acrylate, 2- (4-hydroxyphenyl) ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate, 2- (4-hydroxyphenyl) ethyl methacrylate, and the like. Can be used. Furthermore, as described in US Pat. No. 4,123,279, phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin. A condensation polymer may be used in combination.

(2) Examples of the alkali-soluble polymer compound having a sulfonamide group include a polymer compound obtained by homopolymerizing a polymerizable monomer having a sulfonamide group or copolymerizing the monomer with another polymerizable monomer. . The polymerizable monomer having a sulfonamide group includes one or more sulfonamide groups —NH—SO ₂ — in which at least one hydrogen atom is bonded on a nitrogen atom and one or more polymerizable unsaturated bonds in one molecule. And a polymerizable monomer comprising a low molecular weight compound. Among these, a low molecular compound having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group is preferable.

(3) The alkali-soluble polymer compound having an active imide group is preferably one having an active imide group in the molecule. Examples thereof include a polymer compound obtained by homopolymerizing a polymerizable monomer composed of one or more low-molecular compounds or by copolymerizing the monomer with another polymerizable monomer.
As such a compound, specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

  Furthermore, as the alkali-soluble polymer compound of the present invention, two or more of the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, and the polymerizable monomer having an active imide group are polymerized. It is preferable to use a polymer compound obtained by copolymerizing other polymerizable monomers with these two or more polymerizable monomers. When the polymerizable monomer having a phenolic hydroxyl group is copolymerized with a polymerizable monomer having a sulfonamide group and / or a polymerizable monomer having an active imide group, the blending mass ratio of these components is 50:50 to 5: It is preferably in the range of 95, particularly preferably in the range of 40:60 to 10:90.

  In the present invention, the alkali-soluble polymer is a copolymer of a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, or a polymerizable monomer having an active imide group and another polymerizable monomer. In some cases, the monomer imparting alkali solubility is preferably contained in an amount of 10 mol% or more, more preferably 20 mol% or more. When the copolymerization component is less than 10 mol%, alkali solubility tends to be insufficient, and the development latitude improvement effect may not be sufficiently achieved.

Examples of the monomer component to be copolymerized with the polymerizable monomer having a phenolic hydroxyl group, the polymerizable monomer having a sulfonamide group, or the polymerizable monomer having an active imide group include the compounds listed in the following (m1) to (m12). However, the present invention is not limited to these.
(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.
(M2) Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, and glycidyl acrylate.
(M3) Alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, and glycidyl methacrylate.
(M4) Acrylamide, methacrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl methacrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N-nitrophenyl acrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.
(M6) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.
(M7) Styrenes such as styrene, α-methylstyrene, methylstyrene, chloromethylstyrene.
(M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.
(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene.
(M10) N-vinylpyrrolidone, acrylonitrile, methacrylonitrile and the like.
(M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.
(M12) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.

  The alkaline water-soluble polymer compound preferably has a phenolic hydroxyl group in terms of excellent image-forming properties in exposure with an infrared laser or the like. Further, as the alkaline water-soluble polymer compound having a phenolic hydroxyl group, As described in U.S. Pat. No. 4,123,279, phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin, The condensation polymer of this is mentioned.

As a copolymerization method of the alkaline water-soluble polymer compound, a conventionally known graft copolymerization method, block copolymerization method, random copolymerization method, or the like can be used.
As the alkali-soluble polymer used in the upper recording layer, there is a resin having a phenolic hydroxyl group in that strong hydrogen bonding occurs in the unexposed area, and in the exposed area, some hydrogen bonds are easily released. desirable. More preferred is a novolac resin. A weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 10,000 are preferred.

Hereinafter, a preferred method for forming the dispersed phase in the lower layer will be described.
In the present invention, the selection of the coating solvent is an important factor for setting the dispersed phase constituting the lower sea island structure to a maximum major axis of 0.8 μm or less and an average major axis of 0.6 μm or less. By using it, it becomes possible to produce a sea-island structure having a desired size.
Although there is no clear logic for reducing the dispersed phase by selecting a coating solvent system, as coating solvents, ketone systems such as cyclohexanone and methyl ethyl ketone, methanol, ethanol, propanol, 1-methoxy-2-propanol, etc. Alcohol, cellosolve such as ethylene glycol monomethyl ether, lactone such as γ-butyrolactone, sulfoxide such as dimethyl sulfoxide and sulfolane, halogen such as ethylene dichloride, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate Such as acetates, ethers such as dimethoxyethane, esters such as methyl lactate and ethyl lactate, amides such as N, N-dimethoxyacetamide and N, N-dimethylformamide, N-methylpyrrolidone, etc. It is preferable to use a loridone series, a urea series such as tetramethylurea, an aromatic series such as toluene, etc., among them, methyl ethyl ketone, 1-methoxy-2-propanol, ethylene glycol monomethyl ether, γ-butyrolactone, dimethyl sulfoxide, etc. Is preferred. These solvents may be used alone or in combination.

  In addition to the coating solvent system described above, the conditions for drying the undried coating film after coating with the photosensitive solution are also important in order to make the size of the dispersed phase of the sea-island structure in the lower recording layer predetermined. It is known to be a factor. For the production of such a sea-island structure, reference can be made to the description in JP-A-9-90610.

In the case where a polymer matrix and a dispersed phase are formed using two or more kinds of polymer compounds that are not compatible with each other, the polymer compound used to form the dispersed phase is shown below.
The polymer compound used in the present invention is a copolymer having a structural unit derived from at least one of monomers corresponding to the following (1) to (5), a urethane polymer compound, a novolac resin, Examples include diazo resins and polyethers.
(1) Acrylamides, methacrylamides, acrylic esters and methacrylic esters having an aromatic hydroxyl group. Specific examples include N- (4-hydroxyphenyl) acrylamide or N- (4-hydroxyphenyl) methacrylamide, o-, p-, m-hydroxyphenyl acrylate or methacrylate, 2-hydroxyethyl methacrylate, and the like. It is done.
(2) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride and itaconic acid.
(3) In one molecule, a low molecular compound having at least one sulfonamide group having at least one hydrogen atom bonded to a nitrogen atom and one or more polymerizable unsaturated bonds, for example, the following formulas (I) to (V) ).

In the formula, X ¹ and X ² each represent —O— or —NR ⁷ —. R ¹ and R ⁴ each represent a hydrogen atom or —CH ₃ . R ² , R ⁵ , R ⁹ , R ¹² , and R ¹⁶ each represents an optionally substituted alkylene group having 1 to 12 carbon atoms, a cycloalkylene group, an arylene group, or an aralkylene group. R ³ , R ⁷ and R ^{13 each} represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms which may have a substituent, a cycloalkyl group, an aryl group or an aralkyl group. R ⁶ and R ^{17 each} represents an optionally substituted alkyl group having 1 to 12 carbon atoms, a cycloalkyl group, an aryl group, or an aralkyl group. R ⁸ , R ¹⁰ and R ¹⁴ each represent a hydrogen atom, a halogen atom or —CH ₃ . R ¹¹ and R ¹⁵ each represents a C 1-12 alkylene group, cycloalkylene group, arylene group or aralkylene group which may have a single bond or a substituent. Y ¹ and Y ² each represent a single bond or —CO—.

  Specific examples include m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like.

(4) Low molecular weight compounds each having at least one unsaturated bond polymerizable with an active imino group represented by the following formula (VI) in one molecule, such as N- (p-toluenesulfonyl) methacrylamide, N- (P-toluenesulfonyl) acrylimide and the like.

(5) Styrenic compounds, or vinyl acetate, vinyl alcohol such as o-, m-, p-hydroxystyrene, p-sulfonic acid styrene, o-, m-, p-carboxyl styrene.

  Monomers corresponding to the above (1) to (5) may be used singly or in combination of two or more, but further combined with monomers other than the above polymerizable (1) to (5). A copolymer is preferred. In this case, it is preferable to have 10 mol% or more, preferably 20 mol% or more, more preferably 25 mol% or more of structural units derived from the monomers (1) to (5). Such monomers used in combination with the above monomers (1) to (5) are exemplified by the following (6) to (16).

  (6) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group, such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate.

  (7) Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, glycidyl acrylate, N-dimethylaminoethyl (Substituted) alkyl acrylates such as acrylates.

  (8) (Substitution) such as methyl methacrylate, ethyl methacrylate, pyrrole methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, glycidyl methacrylate, N-dimethylaminoethyl methacrylate Alkyl methacrylate.

  (9) Acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N-ethyl- Acrylamide or methacrylamide such as N-phenylacrylamide.

  (10) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, and phenyl vinyl ether.

  (11) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate.

  (12) Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene.

  (13) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.

  (14) Olefins such as ethylene, propylene, isobutylene, butadiene, and isoprene.

  (15) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like.

  (16) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.

  Furthermore, monomers that can be copolymerized with these monomers may be copolymerized. As these polymer compounds, those having a weight average molecular weight of 2000 or more and a number average molecular weight of 1000 or more are preferably used. More preferably, the weight average molecular weight is 5000 to 300,000, the number average molecular weight is 2000 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10.

Examples of the water-insoluble and alkaline aqueous-soluble urethane polymer compound that can be used in the present invention include, for example, JP-A-63-124047, JP-A-63-287946, JP-A-2-866, and JP-A-2. Although the urethane type polymer compound of each gazette of -156241 is mentioned, it is not limited to these.
In the present invention, the above acrylic polymer compound and urethane polymer compound may be used in combination.

  Examples of the alkali-soluble novolak resin used in the present invention include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p- , M- / p- may be used) Alkali-soluble novolak resins such as mixed formaldehyde resins. As these alkali-soluble novolak resins, those having a weight average molecular weight of 500 to 20,000 and a number average molecular weight of 200 to 10,000 are used. Further, as described in US Pat. No. 4,123,279, condensation of phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin. You may use a thing together.

  In addition, as the diazo resin used in the present invention, a diazo resin, that is, a polymer or oligomer having a diazonio group in the side chain is preferably used. Particularly useful are diazo resins which are condensates of aromatic diazonium salts with, for example, active carbonyl-containing compounds (eg, formaldehyde). Preferred diazo resins include, for example, 4-diazo-diphenylamine, 1-diazo-4-N, N-dimethylaminobenzene, 1-diazo-4-N, N-diethylaminobenzene, 1-diazo-4-N-ethyl. -N-hydroxyethylaminobenzene, 1-diazo-4-N-methyl-N-hydroxyethylaminobenzene, 1-diazo-2,5-diethoxy-4-benzoylaminobenzene, 1-diazo-4-N-benzyl Aminobenzene, 1-diazo-4-morpholinobenzene, 1-diazo-2,5-dimethoxy-4-p-tolylmercaptobenzene, 1-diazo-2-ethoxy-4-N, N-dimethylaminobenzene, 1 -Diazo-2,5-dibutoxy-4-morpholinobenzene, 1-diazo-2,5-diethoxy-4-morpholine Benzene, 1-diazo-2,5-dimethoxy-4-morpholinobenzene, 1-diazo-2,5-diethoxy-4-p-tolylmercaptobenzene, 1-diazo-3-ethoxy-4-N-methyl- N-benzylaminobenzene, 1-diazo-3-chloro-4-N, N-diethylaminobenzene, 1-diazo-3-methyl-4-pyrrolidinobenzene, 1-diazo-2-chloro-4-N, N -Dimethylamino-5-methoxybenzene, 1-diazo-3-methoxy-4-pyrrolidinobenzene, 3-methoxy-4-diazodiphenylamine, 3-ethoxy-4-diazodiphenylamine, 3- (n-propoxy) -4 A diazo monomer such as diazodiphenylamine, 3-isopropoxy-4-diazodiphenylamine, formaldehyde, Condensing agents such as toaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, and benzaldehyde are each in a molar ratio of 1: 1 to 1: 0.5, preferably 1: 0.8 to 1: 0.6. The reaction product of the condensate obtained by condensation by a normal method and an anion is mentioned.

  Examples of the anion used for the reaction include tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, and 2,5-dimethylbenzenesulfonic acid. 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, di-t-butylnaphthalene Examples include sulfonic acid, 1-naphthol-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.

  Further, a reaction product of the above-mentioned diazo monomer, a condensate obtained from an aldehyde having a carboxylic acid and / or phenol or an acetal thereof (and the above-mentioned condensing agent if necessary) and the above-mentioned anion, The diazo resins described in JP-A-1-102456 and JP-A-1-102457 are also preferably used in the present invention. In particular, a diazo resin containing a carboxylic acid group is preferable because developability is improved and, as a result, stains are less likely to occur in a non-image area during printing.

  Among these diazo resins, from the viewpoint that both the decomposability by heat generated by light and the storage stability of the obtained lithographic printing plate precursor are good, the structural unit represented by the following general formula (1), or A diazo resin having a structural unit represented by the general formula (1) and the following general formula (2) and having a weight average molecular weight of 500 or more, preferably 800 or more, more preferably 1000 or more is most preferable. When the weight average molecular weight is less than 500, the film strength of the image portion is lowered. The ratio (mass ratio) of the structural units represented by the formulas (1) and (2) is preferably 100: 0 to 30:70. If the amount of the structural units represented by the formula (1) is small, the strength of the image area is increased. Lower. Further, other structural units may be included.

In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ are each hydrogen, halogen (eg, fluorine, chlorine, bromine), —COOH, —OPO ₃ H ₂ , —PO ₃ H ₂ , — A hydrocarbon group having 15 or less carbon atoms (eg, —COOH, —OPO ₃ H ₂ , —PO ₃ H ₂ , —SO ₃ H, —OH) which may have SO ₃ H, —OH, or a substituent ( For example, carboxymethyl group, hydroxyethyl group, p-carboxymethoxyphenyl group), alkoxy group (for example, methoxy group, hexyloxy group, carboxymethoxy group), aryloxy group (for example, phenoxy group, p-carboxymethoxyphenoxy group) Y represents NR ⁶ , O or S, and R ⁶ represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms (for example, a methyl group, an ethyl group or a hexyl group). X ⁻ represents PF ₆ ^— or benzenesulfonate / naphthalenesulfonate which may have a substituent having 20 or less carbon atoms. Examples of the substituent include a methyl group, a butyl group (including n-, i-, sec-, and t-butyl groups), a hexyl group, a decyl group, a dodecyl group, and a benzoyl group.

  In the case of the positive recording layer, the lower recording layer composed of the polymer matrix containing the dispersed phase formed in this way has an infrared absorber and a compound whose solubility in an alkaline solution is changed by heat in the dispersed phase. It is contained at a high content and efficiently improves the solubility of the polymer matrix layer in an alkaline solution.

  Next, the dispersed phase (2) in the present invention will be described. In the particulate polymer such as microcapsule and latex that can be used in the present invention, the microcapsule is used in the method described in the examples of JP-A-1-145190 or Sankyo publication "New edition microcapsules-production method, properties, and applications". It can be easily prepared by the method described. As for latex, JP-A-10-265710, JP-A-10-270233, JP-A-2-2281, and publication of the polymer publication “Polymer Latex Chemistry”, New Polymer Library “Polymer Latex” It can be prepared by the latex described in 1.

  In this case, examples of the substance included in the capsule and the substance included in the latex include an initiator such as an acid generator and a radical generator, a photothermal conversion material, and a crosslinking agent. In addition, in the lower layer having the dispersed phase of the aspect (2), as the polymer compound that can be used in the polymer matrix for forming the layer, the same compounds as those mentioned in the aspect (1) of the dispersed phase are used in the same manner. Can be used.

The dispersed phase may contain an acid generator that decomposes with light or heat to generate an acid in order to improve the alkaline water solubility of the alkaline water-soluble polymer compound in the exposed area.
The acid generator means a compound that generates acid upon irradiation with light having a wavelength of 200 to 500 nm or heating at 100 ° C. or higher. Examples include known acid generators used for decolorizers, photochromic agents, microresists, and the like, known compounds that generate acid upon thermal decomposition, and mixtures thereof. The acid generated is preferably a strong acid having a pKa of 2 or less, such as sulfonic acid and hydrochloric acid.
Examples of the initiator suitably used in the present invention include triazine compounds described in JP-A No. 11-95415, and latent Brönsted acids described in JP-A No. 7-20629. Here, the latent Bronsted acid refers to a precursor that decomposes to produce a Bronsted acid. The Bronsted acid is believed to catalyze the matrix formation reaction between the resole resin and the novolak resin. Typical examples of Bronsted acids suitable for this purpose are trifluoromethanesulfonic acid and hexafluorophosphonic acid.

  Ionic latent Bronsted acids can be preferably used in the present invention. Examples of these include onium salts, especially iodonium, sulfonium, phosphonium, selenonium, diazonium, and arsonium salts. Specific examples of particularly useful onium salts are: diphenyliodonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, phenylmethyl-ortho-cyanobenzylsulfonium trifluoromethanesulfonate, and 2-methoxy-4-aminophenyldiazonium hexafluorophosphate Is included.

Nonionic latent Bronsted acids are also suitably used in the present invention. These examples are compounds represented by the following formula:
RCH ₂ X, RCHX ₂ , RCX ₃ , R (CH ₂ X) ₂ , and R (CH ₂ X) ₃ , wherein X is Cl, Br, F, or CF ₃ SO ₃ , R is An aromatic group, an aliphatic group or a combination of an aromatic group and an aliphatic group.
Useful ionic latent Bronsted acids are those represented by the following formula:

In the formula, when X is iodine, R ³ and R ⁴ are lone pairs, and R ¹ and R ² are aryl or substituted aryl groups. When X is S or Se, R ⁴ may be a lone pair, and R ¹ , R ² and R ³ may be an aryl group, a substituted aryl group, an aliphatic group or a substituted aliphatic group. When X is P or As, then R ⁴ may be an aryl group, a substituted aryl group, an aliphatic group or a substituted aliphatic group. W can be BF ₄ , CF ₃ SO ₃ , SbF ₆ , CCl ₃ CO ₂ , ClO ₄ , AsF ₆ , PF ₆ , or any corresponding acid whose pH is less than 3. Any onium salt described in US Pat. No. 4,708,925 can be used as the latent Bronsted acid of the present invention. These include indonium, sulfonium, phosphonium, bromonium, chloronium, oxysulfoxonium, oxysulfonium, sulfoxonium, selenonium, telluronium and arsonium salts.

  The use of a diazonium salt as the latent Bronsted acid is particularly preferred in the present invention. They provide sensitivities equivalent to other latent Bronsted acids in the infrared region and higher sensitivity in the ultraviolet region.

  In the present invention, these acid generators are 0.01 to 50% by mass, preferably 0.1 to 25% by mass, based on the total solid content of the lower recording layer, from the viewpoint of image forming properties and prevention of stains in the non-image area. More preferably, it is added at a ratio of 0.5 to 20% by mass.

The positive recording layer of the present invention contains an infrared absorber, which is a component that exhibits a photothermal conversion function. This infrared absorber has a function of converting the absorbed infrared rays into heat, and the laser scanning causes the cancellation of the interaction, the decomposition of the development inhibitor, the generation of acid, etc., and the solubility in the developer is greatly increased. . In addition, the infrared absorber itself may interact with the alkali-soluble resin to suppress alkali solubility.
When such an infrared absorber is contained in the dispersed phase in the lower layer, the infrared absorber is localized in the dispersed phase, and in the case where an interaction releasing property or an acid generator is contained, the decomposition is performed. It is thought that it will improve the performance.
The infrared absorber used in the present invention is a dye or pigment that effectively absorbs infrared rays having a wavelength of 760 nm to 1200 nm. A dye or pigment having an absorption maximum at a wavelength of 760 nm to 1200 nm is preferable.

The infrared absorber that can be suitably used for the lithographic printing plate precursor according to the invention will be described in detail below.
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, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.

  Preferred dyes include, for example, cyanine dyes described in 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-60-63744, etc., naphthoquinone dyes, JP-A-58-112792, etc. And cyanine dyes described in British Patent 434,875.

  Also, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is preferably used, and a substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, Trimethine thiapyrylium salts described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363, 59-84248 Nos. 59-84249, 59-146063, 59-146061, pyranlium compounds, cyanine dyes described in JP-A-59-216146, US Pat. No. 4,283,475 The pentamethine thiopyrylium salts described above and the pyrylium compounds disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 are also preferably used. .

  Another example of a preferable dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

  Among these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes.

  Examples of the pigment used in the present invention include commercially available pigments and color index (CI) manual, “Latest Pigment Handbook” (edited by Japan Pigment Technology Association, published in 1977), “Latest Pigment Application Technology” (CMC Publishing, 1986), “Printing Ink Technology”, CMC Publishing, 1984) can be used.

  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 , Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black, and the like.

  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” (Yokoshobo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). Yes.

  The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably in the range of 0.1 μm to 1 μm. When the particle diameter of the pigment is less than 0.01 μm, it is not preferable from the viewpoint of stability of the dispersion in the image recording layer coating solution, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the image recording layer.

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).
In the case of such a negative recording layer, the infrared absorber is preferably a dye, and particularly preferred dyes are onium salt structures described in paragraphs [0018] to [0034] of JP-A No. 11-291552. Infrared absorbers having

  Since the lithographic printing plate precursor of the present invention has a positive recording layer, the positive action is caused by the interaction with the binder polymer having a specific functional group (dissolution in the unexposed area is suppressed in an alkaline developer, and It is preferable to use an infrared absorber that causes the dissolution inhibiting action to be released, and in that respect, those having an onium salt structure are particularly preferable. Specifically, among the above-described infrared absorbers, cyanine dyes and pyrylium salts are particularly preferable. The details of the cyanine dye and the pyrylium salt are as described above.

Furthermore, the anionic infrared absorber described in Japanese Patent Application No. 10-237634 can also be suitably used. This anionic infrared absorber refers to one having an anion structure without a cation structure in the mother nucleus of a dye that substantially absorbs infrared rays.
For example, (a-1) anionic metal complex and (a-2) anionic phthalocyanine are mentioned.
Here, the (a-1) anionic metal complex refers to an anion that becomes an anion in the central metal and the entire ligand of the complex part that substantially absorbs light.
(A-2) Anionic phthalocyanine refers to a phthalocyanine skeleton having an anion group such as a sulfonic acid, a carboxylic acid, or a phosphonic acid group bonded as a substituent to form an anion as a whole.
Further, an anionic infrared absorber represented by [Ga ⁻ -M-Gb] _m X ^{m +} described in [0014] to [0105] of Japanese Patent Application No. 10-237634 [Ga − represents an anionic substituent; Represents a neutral substituent. X ^{m +} represents a 1 to m-valent cation containing a proton, and m represents an integer of 1 to 6. Can be mentioned.

  The infrared absorber used in the positive recording layer is preferably a dye, and has a suitable onium salt structure described in paragraphs [0018] to [0034] of JP-A No. 11-291652. An infrared absorber is mentioned.

  In the positive recording layer according to the present invention, for the purpose of further improving sensitivity and development latitude, an infrared absorber that exhibits the ability to inhibit the dissolution of the above-mentioned cyanine dyes, pyrylium salts, anionic dyes, and the like, A dye or pigment may be used in combination.

  In the present invention, the infrared absorbing agent is 0.01 to 50 from the viewpoint of image forming property and suppression of occurrence of contamination in the non-image area with respect to the total solid content of each recording layer in the lower recording layer and other recording layers. It is preferable to add mass%, More preferably, it is 0.1-20 mass%, More preferably, it is 0.5-15 mass%.

  The infrared absorber may be contained in either the matrix phase or the dispersed phase, or may be contained in both, but the desired components such as the initiator and the infrared absorber in the latex constituting the dispersed phase as described above. When it is added, it may be added together with the raw material when forming the latex particles, or may be introduced after forming the latex.

  Examples of the method of introducing after forming the latex include a method in which desired components such as an initiator, a color system, and a crosslinking agent to be introduced are dissolved in an organic solvent and added to a dispersion medium.

  As described above, the recording layer of the lithographic printing plate precursor according to the present invention is required not to cause ablation in relation to the infrared laser irradiation apparatus. From the viewpoint of preventing ablation, the recording layer is used. As the polymer material that constitutes the binder, any material can be used as long as its solubility in alkaline water, that is, an alkaline developer, is changed by the application of thermal energy. From the viewpoint of difficulty, it is preferable to use a polymer that is insoluble in water and soluble in alkaline water.

  In addition, as an index of the difficulty of ablation, it is possible to select a polymer having a high ceiling temperature, that is, a temperature at which the rate of the polymerization reaction and the depolymerization reaction becomes equal in a polymerization reaction of a vinyl compound or the like. For simplicity, the decomposition temperature of the polymer can be selected as an index. In the present invention, the polymer constituting the recording layer preferably has a decomposition temperature of 150 ° C. or higher, and more preferably has a decomposition temperature of 200 ° C. or higher. If the decomposition temperature is less than 150 ° C., the possibility of ablation increases, which is not preferable. Components other than the polymer compound contained in the recording layer preferably have a decomposition temperature of 150 ° C. or higher. However, components with a small addition amount include components having a decomposition temperature of less than 150 ° C. as long as they do not cause any problems. Can be used.

  In the recording layer of the lithographic printing plate precursor according to the invention, various known additives can be used in combination with the above-described constituent components in accordance with the purpose. Of the plurality of recording layers, it is necessary to form a dispersed phase in the lower recording layer, but the same additive can be used for the lower layer and the other recording layers for the other additives.

[Fluorine-containing polymer]
A fluoropolymer is preferably added to each recording layer of the present invention for the purpose of improving the development resistance of the image area. Examples of the fluorine-containing polymer used in the image recording layer include fluorine-containing monomer copolymers as described in JP-A Nos. 11-288093 and 2000-187318.
Preferable specific examples include acrylic polymers containing fluorine of P-1 to P-13 described in JP-A No. 11-288093 and A-1 to JP-A No. 2000-187318. A fluorine-containing polymer obtained by copolymerizing an A33 fluorine-containing acrylic monomer with an arbitrary acrylic monomer can be used.
As the molecular weight of the fluorine-containing polymer mentioned above, those having a weight average molecular weight of 2000 or more and a number average molecular weight of 1000 or more are preferably used. More preferably, the weight average molecular weight is 5000 to 300000, and the number average molecular weight is 2000 to 250,000.

In addition, as the fluorine-containing polymer, a commercially available fluorine-based surfactant that is a compound having the preferred molecular weight can also be used. As specific examples, MegaFuck F-171, F-173, F-176, F-183, F-184, F-780, F-781 (all trade names) manufactured by Dainippon Ink and Chemicals, Inc. are used. Can be mentioned.
These fluorine-containing polymers may be used alone or in combination of two or more.
The addition amount is 1.4% by mass or more based on the solid content of the image recording layer as a requirement of the present invention. A preferable addition amount is 1.4 to 5.0% by mass. When the amount is less than 1.4% by mass, the effect of improving the development latitude of the image recording layer, which is the purpose of adding the fluorine-containing polymer, cannot be sufficiently obtained. Note that even if it exceeds 5.0 mass%, the effect of improving the development latitude is not improved, and on the contrary, there is a concern that the surface of the image recording layer becomes slightly soluble due to the influence of the fluorine-containing polymer and the sensitivity is lowered.

[Other ingredients]
The lower recording layer or other recording layer according to the present invention is further thermally decomposable such as an onium salt, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, etc. Substances that substantially reduce the solubility of the polymer compound can be used in combination. Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts, and the like.

  Preferred examples of the onium salt that can be used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Baletal, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, US Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140 Ammonium salts described in the C. Necker et al., Macromolecules, 17, 2468 (1984), C.I. S. Wenetal, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al., Macromolecules, 10 (6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, US Pat. Nos. 5,041,358, 4,491,628, JP-A-2-150848 and JP-A-2-296514. Iodonium salt,

J. et al. V. Crivello et al., Polymer J .; 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Wattal, J. et al. PolymerSci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al., Polymer Bull. 14, 279 (1985), J. Am. V. Crivello et al., Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al. PolymerSci. , Polymer Chem. Ed. 17, 2877 (1979), European Patents 370,693, 233,567, 297,443, 297,442, U.S. Pat. Nos. 4,933,377, 3,902,114 No. 4,491,628, No. 5,041,358, No. 4,760,013, No. 4,734,444, No. 2,833,827, German Patent No. 2,904 No. 626, No. 3,604,580, No. 3,604,581, sulfonium salts described in J.P. V. Crivello et al., Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al. PolymerSci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wenetal, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).

In the present invention, a diazonium salt is particularly preferable. Particularly suitable diazonium salts include those described in JP-A-5-158230.
The counter ion of the onium salt includes tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2-nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfone Examples include 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.

Further, for the purpose of enhancing the discrimination of the image and the resistance against scratches on the surface, a perfluoroalkyl group having 3 to 20 carbon atoms in the molecule as described in JP-A-2000-87318. A polymer having a (meth) acrylate monomer having 2 or 3 as a polymerization component can be used in combination.
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, Trachlorophthalic 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 described in Japanese Laid-Open Patent Application No. 60-88942 and Japanese Patent Laid-Open No. 2-96755. p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl sulfate, phenyl Suphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-methoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene-1,2 -Dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid, etc. The proportion of the cyclic acid anhydride, phenols and organic acids in the printing plate material is 0.05 to 20 mass. % Is preferable, more preferably 0.1 to 5% by mass, and particularly preferably 0.1 to 10% by mass.

  For example, a dye having a large absorption in the visible light region can be added to each recording layer according to the present invention as an image colorant. 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 (orientated chemistry) Manufactured by Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI52015), Eisenspiron Blue C-RH ( Hodogaya Chemical Co., Ltd.) and the dyes described in JP-A-62-293247.

  By adding these dyes, the image portion and the non-image portion are clearly distinguished after the image formation, so that it is preferable to add them. The addition amount is preferably in the range of 0.01 to 10% by mass with respect to the total solid content of the recording layer.

Further, in the recording layer of the present invention, a nonionic surfactant as described in JP-A-62-251740 or JP-A-3-208514 is used in order to broaden the processing stability against development conditions. Amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149, siloxane-based compounds as described in EP950517, JP-A-11-288093 Copolymers containing fluorine monomers as described 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.) and the like. The siloxane compound is preferably a block copolymer of dimethylsiloxane and polyalkylene oxide. Specific examples include DBE-224, DBE-621, DBE-712, DBP-, manufactured by Chisso Corporation. Polyalkylene oxide-modified silicones such as 732, DBP-534, and Tego Glide 100 manufactured by Tego, Germany.
The proportion of the nonionic surfactant and the amphoteric surfactant in the printing plate material is preferably 0.05 to 15% by mass, more preferably 0.1 to 5% by mass.

In the recording layer material 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, for example, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A Nos. 50-36,209 and 53-8128, Trihalomethyl compounds and salts described in JP-A Nos. 53-36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440 Examples of such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images. Examples of other photoacid releasing agents include various o-naphthoquinonediazide compounds described in JP-A-55-62444; 2-trihalomethyl-5--5 described in JP-A-55-77742. Examples include aryl-1,3,4-oxadiazole compounds; diazonium salts.

  Furthermore, a plasticizer is added to the image recording layer and the lower layer coating solution of the present invention, if necessary, 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.

The lithographic printing plate precursor according to the invention can be usually produced by sequentially applying a lower layer coating solution obtained by dissolving the above-described components in a solvent, and further an upper recording layer coating solution onto a suitable support.
Suitable solvents for applying the lower layer and the image recording layer 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, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, etc. However, the present invention is not limited to this. 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 lower layer (lower recording layer) and the upper layer (other recording layers) are preferably formed by separating the two layers in principle.

As a method for forming the two layers separately, for example, a method using a difference in solvent solubility between a component contained in the lower layer and a component contained in the upper layer, or after applying the upper layer, a solvent is rapidly used. However, it is not limited to these methods.
As a method of utilizing the difference in solvent solubility between the component contained in the lower layer and the component contained in the upper layer, a method using a solvent that does not dissolve the alkali-soluble resin contained in the lower layer when applying the upper layer coating solution. Can be mentioned. Thereby, even if it carries out 2 layer application | coating, it becomes possible to isolate | separate each layer clearly and to make a coating film. For example, as the lower layer component, a component insoluble in a solvent such as methyl ethyl ketone or 1-methoxy-2-propanol that dissolves the alkali-soluble resin that is the upper layer component is selected, and the lower layer is applied using a solvent system that dissolves the lower layer component. -Drying and then dissolving the upper layer mainly composed of an alkali-soluble resin with methyl ethyl ketone, 1-methoxy-2-propanol or the like, and applying and drying can be made into two layers.

  When applying a method that uses a solvent that does not dissolve the alkali-soluble resin contained in the lower layer when applying the upper layer coating solution, the upper layer coating solvent does not dissolve in the solvent that dissolves the alkali-soluble resin contained in the lower layer. You may mix and use a solvent. By changing the mixing ratio of the two solvents, interlayer mixing between the upper layer and the lower layer can be arbitrarily controlled. When the ratio of the solvent that dissolves the alkali-soluble resin in the lower layer increases, a part of the lower layer dissolves when the upper layer is applied, and after drying, it is contained as a particulate component in the upper layer. Protrusions are made and scratch resistance is improved. On the other hand, when the lower layer components are dissolved into the upper layer, the film quality of the lower layer is lowered, and the chemical resistance tends to be lowered. In this way, by controlling the mixing ratio in consideration of each physical property, various characteristics can be expressed, and further, partial compatibility between layers described later can be caused.

  From the viewpoint of the effect of the present invention, when the above mixed solvent is used as the upper layer coating solvent, the solvent for dissolving the lower layer alkali-soluble resin should be 80% by mass or less of the upper layer coating solvent. From the viewpoint, it is preferably in the range of 10 to 60% by mass in consideration of scratch resistance.

Next, after applying the second layer (upper layer), as a method of drying the solvent very quickly, high-pressure air is blown from a slit nozzle installed substantially perpendicular to the web running direction, or heating such as steam This can be achieved by applying thermal energy as conduction heat from the lower surface of the web from a roll (heating roll) supplied inside the medium, or by combining them.
In the present invention, various methods can be used as a method for coating each layer such as an image recording layer. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating. , Roll coating and the like.
In particular, in order to prevent damage to the lower layer when the upper layer is applied, the upper layer application method is preferably a non-contact type. Further, although it is a contact type, it is possible to use bar coater coating as a method generally used for solvent-based coating, but it is desirable to perform coating by forward rotation in order to prevent damage to the lower layer.

The coating amount after drying of the lower recording layer in the planographic printing plate precursor of the present invention is in the range of 0.5 to 1.5 g / m ² from the viewpoint of securing printing durability and suppressing the occurrence of residual film during development. Is more preferable, and the range of 0.7 to 1.0 g / m ² is more preferable.
The coating amount after drying of the image recording layer (upper layer) is preferably in the range of 0.05 to 1.0 g / m ^2, more preferably in the range of 0.07~0.7g / m ² is there. In addition, the total amount is shown when there are two or more upper layers.
In these recording layers, generally, as the coating amount decreases, the apparent sensitivity increases, but the development latitude and film characteristics tend to decrease. In particular, when the thickness of the recording layer is too thick, the recording layer is easily affected by thermal diffusion in the deep part, and there is a concern that the image formability in the vicinity of the support is lowered.

  In the coating solution for the lower layer or the other recording layer in the present invention, a surfactant for improving the coating property, for example, a fluorine-based surfactant as described in JP-A-62-170950 is used. Can be added. A preferable addition amount is 0.01 to 1% by mass of the total solid content of the coating solution, and more preferably 0.05 to 0.5% by mass.

[Support]
The support used in the present invention is not particularly limited as long as it is a dimensionally stable plate-like material. For example, paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), metal Plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, Polyvinyl acetal, etc.), paper laminated with metal as described above, or vapor-deposited paper, or plastic film.
As the support used in the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. 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 foreign 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. However, in general, 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 / day. dm ² , voltage 1 to 100 V, and electrolysis time 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 part of the lithographic printing plate is easily scratched, and the ink adheres to the scratched part during printing. So-called “scratch stains” easily occur.

After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary.
The hydrophilization treatment used in the present invention is disclosed in US Pat. Nos. 2,714,066, 3,181,461, 3,280,734 and 3,902,734. There are alkali metal silicate (such as aqueous sodium silicate) methods. In this method, the support is immersed in an aqueous sodium silicate solution or electrolytically treated. In addition, it is disclosed in potassium fluoride zirconate disclosed in Japanese Patent Publication No. 36-22063 and U.S. Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinyl phosphonic acid is used.

The lithographic printing plate precursor according to the present invention is provided by laminating at least two layers of the lower recording layer and the upper recording layer on a support. If necessary, the planographic printing plate precursor may be provided between the support and the lower layer. A coating layer can be provided.
Various organic compounds are used as an undercoat layer component. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and optionally substituted phenylphosphonic acid Organic phosphonic acids such as naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphonic acid, alkylphosphoric acid and glycerophosphoric acid Organic phosphoric acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid, glycerophosphinic acid and other organic phosphinic acids, glycine and β-alanine amino acids, and triethanolamine hydrochloric acid Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of 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 a basic substance such as ammonia, triethylamine or potassium hydroxide, or an acidic substance such as hydrochloric acid or 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.

The positive lithographic printing plate precursor produced as described above is usually subjected to image exposure and development processing.
Examples of the active light source used for image exposure include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Examples of radiation include electron beams, X-rays, ion beams, and far infrared rays. Also, g-line, i-line, deep-UV light, and high-density energy beam (laser beam) are used.
Examples of the laser beam include helium / neon laser, argon laser, krypton laser, helium / cadmium laser, and KrF excimer laser.
In the present invention, it is particularly preferable to perform exposure with a light source having a light emission wavelength from the near infrared region to the infrared region. It is preferable.

  The lithographic printing plate precursor according to the invention is subjected to development treatment with water or an alkali developer after exposure. The development treatment may be performed immediately after the exposure, but a heat treatment may be performed between the exposure step and the development step. When the heat treatment is performed, it is preferable that the conditions be within a range of 60 ° C. to 150 ° C. for 5 seconds to 5 minutes. As the heating method, various conventionally known methods can be used. For example, a method of heating while contacting a recording material with a panel heater or a ceramic heater, a non-contact heating method with a lamp or hot air, and the like can be mentioned. This heat treatment can reduce the laser energy required for recording during laser irradiation.

Conventionally known alkaline aqueous solutions can be used as the developer and replenisher used in the plate making of the lithographic printing plate of the present invention.
The developer that can be applied to the development processing of the lithographic printing plate precursor according to the invention is a developer having a pH in the range of 9.0 to 14.0, preferably in the range of 12.0 to 13.5. A conventionally known alkaline aqueous solution can be used for the developer (hereinafter referred to as a developer including a replenisher). For example, sodium silicate, potassium, trisodium 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. In addition, 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 listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

Further, an alkaline aqueous solution composed of a non-reducing sugar and a base can be used. Non-reducing sugar means a saccharide that does not have a free aldehyde group or ketone group and therefore has no reducing ability. Trehalose-type oligosaccharides in which reducing groups are bonded to each other, saccharide reducing groups and non-saccharides are bonded to each other Sugar sugars are classified into sugar alcohols reduced by hydrogenation of sugars. Any of these is preferably used in the present invention.
Examples of trehalose type oligosaccharides include saccharose and trehalose. Examples of glycosides include alkyl glycosides, phenol glycosides, mustard oil glycosides, and the like. Examples of the sugar alcohol include D, L-arabit, rebit, xylit, D, L-sorbit, D, L-mannit, D, L-exit, D, L-talit, durisit and allozulcit. Furthermore, maltitol obtained by hydrogenation of a disaccharide and a reduced form (reduced water candy) obtained by hydrogenation of an oligosaccharide are preferably used. Among these, sugar alcohol and saccharose are particularly preferred non-reducing sugars, and D-sorbite, saccharose, and reduced starch syrup are particularly preferred because they have a buffering action in an appropriate pH region and are inexpensive.

These non-reducing sugars can be used alone or in combination of two or more thereof, and the proportion of the non-reducing sugar in the developer is preferably from 0.1 to 30% by mass, and more preferably from 1 to 20% by mass.
A conventionally known alkaline agent can be used as the base to be combined with the non-reducing sugar. For example, sodium hydroxide, potassium hydroxide, lithium hydroxide, trisodium phosphate, tripotassium phosphate, triammonium phosphate, disodium phosphate, dipotassium phosphate, diammonium phosphate, sodium carbonate, potassium carbonate, Examples include inorganic alkali agents such as ammonium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogen carbonate, sodium borate, potassium borate, and ammonium borate. In addition, 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, sodium hydroxide and potassium hydroxide are preferable. The reason is that the pH can be adjusted in a wide pH range by adjusting the amount added to the non-reducing sugar. Further, trisodium phosphate, sodium carbonate, potassium carbonate and the like are preferable because they themselves have a buffering action.

  When developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than the developer is added to the developer, so that a large amount of PS can be obtained without replacing the developer in the developer tank for a long time. It is known that plates 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. When the lithographic printing plate precursor according to the invention is used as a printing plate, these treatments can be used in various combinations as post-treatments.

  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 can also be applied.

  The processing method of the heat-sensitive lithographic printing plate precursor according to the present invention will be described. If there is an unnecessary image part (for example, film edge mark of the original film) on the planographic printing plate obtained by image exposure, development, washing and / or rinsing and / or gumming, it is unnecessary. The image portion is erased. Such erasing is preferably performed by applying an erasing solution as described in, for example, Japanese Patent Publication No. 2-13293 to an unnecessary image portion, 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-5-174842 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 a higher printing durability, a burning treatment is performed. Is given. 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 planographic printing plate coated with the surface-adjusting solution 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.). The The heating temperature and time in this case are preferably in the range of 180 to 300 ° C. and 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 or the like is used. If so, so-called desensitizing treatment such as gumming can be omitted.
The lithographic 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 Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.
(Examples 1-3)
[Production of substrate]
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.014 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: It contains 0.03% by mass, and the balance is prepared using Al and an inevitable impurity aluminum alloy. After the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, the temperature was kept constant at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Further, heat treatment was performed at 500 ° C. using a continuous annealing machine, and then finished into an aluminum plate having a thickness of 0.24 mm by cold rolling. After making this aluminum plate into width 1030mm, it used for the surface treatment shown below.

<Surface treatment>
The surface treatment was performed by continuously performing the following various treatments (a) to (j). In addition, after each process and water washing, the liquid was drained with the nip roller.
(A) Mechanical surface roughening treatment While supplying a suspension of abrasive (silica sand) having a specific gravity of 1.12. 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) Etching treatment with alkali agent The aluminum plate obtained above is subjected to an etching treatment by spraying using an aqueous solution having a caustic soda concentration of 2.6 mass%, an aluminum ion concentration of 6.5 mass%, and a temperature of 70 ° C. 10 g / m ^{2 was} dissolved. Then, water washing by spraying was performed.
(C) Desmut treatment temperature 30 ° C. A nitric acid concentration 1% by mass aqueous solution (containing 0.5% by mass of aluminum ions) was subjected to a desmut treatment by spraying, 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 10.5 g / L aqueous solution of nitric acid (containing 5 g / L of aluminum ions and 0.007% by mass of ammonium ions) at a liquid temperature of 80 ° C.
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. Then, water washing by spraying was performed.
(E) Alkaline etching treatment An aluminum plate is subjected to an etching treatment by spraying at 32 ° C. using an aqueous solution having a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to dissolve the aluminum plate by 0.20 g / m ^2. The smut component mainly composed of aluminum hydroxide generated when the electrochemical surface roughening process is performed using the alternating current of the previous stage is removed, and the edge portion of the generated pit is melted to smooth the edge portion. I made it. Then, water washing by spraying was performed.
(F) Desmutting treatment Desmutting treatment was carried out by spraying with a 25% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), followed by washing with water by spraying.

(G) Anodizing treatment Anodizing apparatus of two-stage feeding electrolytic treatment method (first and second electrolytic section length 6 m each, first and second feeding section length 3 m each, first and second feeding electrode length 2.4 m each) Anodizing was performed using Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 170 g / L (containing 0.5 mass% of aluminum ions) and a temperature of 43 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.7 g / m ² .
(H) Alkali metal silicate treatment The aluminum support obtained by anodizing treatment was immersed in a treatment layer of a 1% by weight aqueous solution of sodium silicate No. 3 at a temperature of 30 ° C. for 10 seconds to immerse the alkali metal silica. Acid salt treatment (silicate treatment) was performed. Then, water washing by spraying was performed.

(I) Formation of undercoat layer 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. Formed. The coating amount of the coating film after drying was 15 mg / m ² .
<Undercoat liquid composition>
・ The following compound 1 0.3g
・ Methanol 100g
・ Water 1g

After applying the following lower layer coating solution to the obtained substrate so that the coating amount becomes 0.85 g / m ² , Wind Control is set to 7 at PERFECT OVEN PH200 manufactured by Tabai Co. Then, the upper image recording layer coating solution was applied so that the coating amount was 0.15 g / m ^2, and then dried at 120 ° C. for 1 minute to obtain lithographic printing plate precursors 1 to 3.

[Coating liquid for lower recording layer]
N- (4-aminosulfonylphenyl) methacrylamide / acrylonitrile / methyl methacrylate [addition amounts shown in Table 1: A (g)]
(36/34/30: weight average molecular weight 100,000, acid value 2.65)
-M, p-cresol novolak [Addition amount described in Table 1: B (g)]
(M / p ratio = 6/4, weight average molecular weight 4500, containing unreacted cresol 0.8% by mass)
・ Cyanine dye A (the following structure: mixed system) 0.109 g
・ 4,4′-bishydroxyphenylsulfone [Addition amount shown in Table 1: C (g)]
・ Tetrahydrophthalic anhydride 0.190g
・ 0.008 g of p-toluenesulfonic acid
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalene sulfone 0.10 g
・ Fluorosurfactant (Surface improving surfactant) 0.035 g
(Megafuck F781F, manufactured by Dainippon Ink & Chemicals, Inc.)
・ 0.003 g of the compound described in Example 9 of JP-A-10-186649
(2-diazo-1,2-dihydro-1-oxo-5-naphthalenesulfonyl chloride (in 3%)
A cresol-formaldehyde novolac resin derived using
Schenectady Chemical)
・ Methyl ethyl ketone 24.38g
・ 13.0 g of 1-methoxy-2-propanol
・ 14.2 g of γ-butyrolactone

[Coating liquid for upper recording layer]
・ M, p-cresol novolak 0.2846g
(M / p ratio = 6/4, weight average molecular weight 4500, containing unreacted cresol 0.8% by mass)
・ Cyanine dye A (the above structure) 0.075 g
・ Behenamide 0.060g
-Fluorosurfactant (Surface improving surfactant) 0.022g
[Megafuck F781F, manufactured by Dainippon Ink & Chemicals, Inc.]
・ Image formation improved fluorosurfactant 0.120g
[Megafuck F780 (30%), manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 15.1g
-1-methoxy-2-propanol 7.7g

(Examples 4 to 6)
Lithographic printing plate precursors 4 to 6 were obtained in the same manner as in Example 1 except that the lower recording layer coating solution used in Example 1 was changed to the following.
[Coating liquid for lower recording layer]
N- (4-aminosulfonylphenyl) methacrylamide /
Acrylonitrile / methyl methacrylate [addition amounts shown in Table 2: D (g)]
(36/34/30: weight average molecular weight 100,000, acid value 2.65)
PD-1 (the following structure) [Addition amount described in Table 2: E (g)]
・ Dye C (the following structure) 0.109g
・ 4,4'-bishydroxyphenylsulfone 0.126g
・ Tetrahydrophthalic anhydride 0.190g
P-Toluenesulfonic acid [Addition amount described in Table 2: F (g)]
・ 2,4-Bis (2-diazo-1,2-dihydro-1-oxo-5-naphthalenesulfonyloxy) benzophenone 0.030 g
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalene sulfone 0.10 g
・ PC-A (the following structure) 0.007g
・ Methyl ethyl ketone 25.36g
・ 13.0 g of 1-methoxy-2-propanol
・ Γ-butyrolactone 13.2 g

(Example 7)
A lithographic printing plate precursor 7 was obtained in the same manner as in Example 1 except that the application amount of the upper recording layer in Example 1 was 0.20 g / m ² .
(Example 8)
In the substrate production of Example 1, (h) without alkali metal silicate treatment, (i) in the formation of the undercoat layer, an undercoat solution having the following composition was applied, dried at 80 ° C. for 30 seconds, and after drying A lithographic printing plate precursor 8 was obtained in the same manner as in Example 1 except that the coating amount was 10 mg / m ² .

(Undercoat liquid)
β-Alanine 0.1g
Phenylsulfonic acid 0.05g
40g of methanol
60g of pure water

Example 9
[Production of substrate]
Si: 0.06 mass%, Fe: 0.30 mass%, Cu: 0.025 mass%, Mn: 0.001 mass%, Mg: 0.001 mass%, Zn: 0.001 mass%, Ti: It contains 0.03% by mass, and the balance is prepared by using an aluminum alloy of Al and inevitable impurities. After the molten metal treatment and filtration, an ingot having a thickness of 500 mm and a width of 1200 mm is obtained by a DC casting method. Created. After the surface was shaved with a chamfering machine with an average thickness of 10 mm, the temperature was kept constant at 550 ° C. for about 5 hours, and when the temperature dropped to 400 ° C., rolling with a thickness of 2.7 mm using a hot rolling mill A board was used. Further, after heat treatment was performed at 500 ° C. using a continuous annealing machine, an aluminum plate having a thickness of 0.30 mm was finished by cold rolling. After making this aluminum plate 1030 mm in width, the following surface treatment was continuously performed.
(A) Mechanical roughening treatment (brush grain method)
While supplying an aqueous suspension (specific gravity 1.1 g / cm ³ ) of an abrasive (pumice) as a polishing slurry liquid to the surface of the aluminum plate, a mechanical surface roughening treatment was performed with a rotating roller brush. The median diameter of the abrasive was 33 μm. As for the roller-like brush, a nylon brush was planted so as to be dense by making a hole in a stainless steel cylinder having a diameter of 400 mm. 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 distance between the surfaces of the two support rollers (φ250 mm) under the brush was 300 mm. The roller brush was pressed until the load of the drive motor for rotating the brush became 10 kW plus with respect to the load before the roller brush was pressed against the aluminum plate.

(B) Etching treatment with alkali agent The aluminum plate after the mechanical surface-roughening treatment obtained above is sprayed with an aqueous caustic soda solution having a caustic soda concentration of 2.6 mass% and an aluminum ion concentration of 5 mass%, so that the aluminum dissolution amount is 10 g. Etching was performed at / m ² . Then, water washing by spraying was performed. The temperature for the alkali etching treatment was 70 ° C.
(C) Desmutting treatment Desmutting treatment was performed by spraying with a 1% by weight aqueous solution of nitric acid at a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying.
(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 10% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 35 ° C.
The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in the nitric acid electrolysis was 197 C / dm ^{2 as} the total amount of electricity when the aluminum plate was the anode.
Then, water washing by spraying was performed.

(E) Alkali etching treatment An aluminum plate was subjected to spraying aging treatment at 70 ° C. with a caustic soda concentration of 26 mass% and an aluminum ion concentration of 6.5 mass% to dissolve the aluminum plate by 3.8 g / m ² . Then, water washing by spraying was performed.
(F) Desmut treatment A desmut treatment by spraying was performed with a 1% by mass aqueous solution of nitric acid having a temperature of 30 ° C. (containing 0.5% by mass of aluminum ions), followed by washing with water by spraying.
(G) Anodizing treatment An electrochemical surface roughening treatment was performed continuously using an alternating voltage of 60 Hz. The liquid temperature was 40 ° C. The AC power supply waveform is the waveform shown in FIG. 1. The time TP until the current value reaches a peak from zero is 0.8 msec, the duty ratio is 1: 1, a trapezoidal rectangular wave AC is used, with the carbon electrode as the counter electrode An electrochemical roughening treatment was performed. Ferrite was used for the auxiliary anode.
The current density was 25 A / dm ² at the peak current value.
The electrolytic solution used for hydrochloric acid electrolysis was an aqueous solution containing 5.0% by mass hydrochloric acid (including 5.0% by mass of aluminum ions), and the amount of electricity in hydrochloric acid electrolysis was 60 C / It was dm ^2. The electrolytic layer shown in FIG. 2 was used.
Then, water washing by spraying was performed.

(H) Alkaline Etching Treatment Etching was performed by spraying a caustic soda aqueous solution having a caustic soda concentration of 4.5% by mass and an aluminum ion concentration of 0.5% by mass with an aluminum dissolution amount of 0.16 g / m ² . Then, water washing by spraying was performed. The temperature for the alkali etching treatment was 70 ° C. Then, water washing by spraying was performed.
(I) Desmutting treatment A desmutting treatment was carried out by spraying with a 25% by weight aqueous solution of sulfuric acid at a temperature of 60 ° C. (including 0.5% by weight of aluminum ions), followed by washing with water by spraying.
(J) Anodizing treatment Anodizing apparatus of two-stage feeding electrolytic treatment method (first and second electrolytic section length 6 m each, first and second feeding section length 3 m each, first and second feeding electrode length 2.4 m each) Anodizing was performed using
Sulfuric acid was used as the electrolytic solution supplied to the first and second electrolysis units. All electrolytes had a sulfuric acid concentration of 15% by mass (including 0.5% by mass of aluminum ions) and a temperature of 38 ° C. Then, water washing by spraying was performed. The final oxide film amount was 2.5 g / m ² .

(K) Formation of undercoat layer On the aluminum support after the alkali metal silicate treatment obtained as described above, the same undercoat liquid as used in Example 1 was applied, and then at 80 ° C for 15 seconds. Dried to form a coating film. The coating amount of the coating film after drying was 15 mg / m ² .
A lithographic printing plate precursor 9 was obtained in the same manner as in Example 1 except that the above substrate was used.

(Comparative Example 1)
A lithographic printing plate precursor 10 was obtained in the same manner as in Example 1 except that the lower layer coating solution of Example 1 was changed to the following.

[Lower layer coating solution]
N- (4-aminosulfonylphenyl) methacrylamide /
Acrylonitrile / methyl methacrylate 2.133 g
(36/34/30: weight average molecular weight 100,000, acid value 2.65)
・ Cyanine dye A (the above structure) 0.109 g
・ 4,4'-bishydroxyphenylsulfone 0.126g
・ Tetrahydrophthalic anhydride 0.190g
・ 0.008 g of p-toluenesulfonic acid
・ 3-methoxy-4-diazofudiphenylamine hexafluorophosphate 0.030 g
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalene sulfone 0.10 g
・ Fluorine-based surfactant (surfactant for improving coated surface) 0.035 g
[Megafuck F176 (20%), manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 25.38g
・ 13.0 g of 1-methoxy-2-propanol
・ Γ-butyrolactone 13.2 g

(Comparative Example 2)
A lithographic printing plate precursor 11 was obtained in the same manner as in Example 1 except that the lower layer coating solution of Example 1 was changed to the following.
[Lower layer coating solution]
PD-1 (said compound) 2.133 g
・ Cyanine dye A (the above structure) 0.109 g
・ 4,4'-bishydroxyphenylsulfone 0.126g
・ Tetrahydrophthalic anhydride 0.190g
・ 0.008 g of p-toluenesulfonic acid
・ 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 g
・ The counter ion of ethyl violet is changed to 6-hydroxynaphthalene sulfone 0.10 g
・ Fluorine-based surfactant (surfactant for improving coated surface) 0.035 g
[Megafuck F176 (20%), manufactured by Dainippon Ink & Chemicals, Inc.]
・ Methyl ethyl ketone 25.38g
・ 13.0 g of 1-methoxy-2-propanol
・ Γ-butyrolactone 13.2 g

(Confirmation of dispersed phase)
After imparting conductivity to the recording layer section obtained by cutting the lithographic printing plate precursors of Examples 1 to 9 and the lithographic printing plate precursors of Comparative Examples 1 and 2 with a microtome or the like, using a scanning electron microscope (SEM) When photographed and observed, it was confirmed that each lower recording layer dispersed phase of Examples 1 to 9 was present. The size of the dispersed phase was in the range of 0.05 to 0.55 μm. On the other hand, the lower recording layer of Comparative Example 1 and Comparative Example 2 was a uniform phase, and no dispersed phase was observed.

[Evaluation of lithographic printing plate precursor]
[Evaluation of sensitivity]
The obtained lithographic printing plate precursors 1 to 6 of the present invention and the lithographic printing plate precursors 7 and 8 of the comparative examples were drawn with a test pattern in the form of an image by changing the exposure energy with a Trend setter manufactured by Creo.
Thereafter, development is performed with a developer DT-2 (diluted to a conductivity of 43 mS / cm) manufactured by Fuji Photo Film Co., Ltd., and the exposure energy that can develop the non-image area with this developer is measured. did. The smaller the numerical value, the higher the sensitivity. The results are shown in Table 3.
[Evaluation of development latitude]
The obtained lithographic printing plate precursors 1 to 9 of the present invention and the lithographic printing plate precursors 10 and 11 of the comparative example were drawn in a test pattern in an image shape at a beam intensity of 9 w and a drum rotation speed of 150 rpm using a Trend setter manufactured by Creo. It was.
First, a PS processor 940HII manufactured by Fuji Photo Film Co., Ltd., prepared by changing the dilution ratio of the developer DT-2 manufactured by Fuji Photo Film Co., Ltd., was used for the lithographic printing plate precursors 1-11 exposed under the above conditions. The liquid temperature was kept at 30 ° C., and development was performed for 12 seconds. At this time, it was confirmed whether there was any stain or coloring due to a defective recording layer remaining film, and the conductivity of the developer that was able to be developed satisfactorily was measured.
The results are shown in Table 3 below. Those having a large difference between the upper limit value and the lower limit value are evaluated as being excellent in development latitude.

[Evaluation of scratch resistance]
The lithographic printing plates 10 and 11 of Examples 1 to 9 and Comparative Examples 1 and 2 thus obtained were rubbed 15 times with Abrazer felt CS5 under a load of 250 g using a rotary ablation tester (manufactured by TOYOSEIKI).
After that, a modified version of the developer DT-2 manufactured by Fuji Photo Film Co., Ltd. was charged with DT-2 (DT-2: diluted with water = 1: 8). Using a PS processor 940HII manufactured by Fuji Photo Film Co., Ltd., the liquid temperature was kept at 30 ° C., and development was performed for 12 seconds. At this time, the developing electric power was 45 mS / cm. The scratch resistance was evaluated according to the following criteria. Above Δ is a level with no practical problem. The results are shown in Table 3 below.
<Evaluation criteria for scratch resistance>
○: The optical density of the photosensitive film in the rubbed part was not changed at all. Δ: The optical density of the photosensitive film in the rubbed part was slightly observed visually. ×: The optical density of the photosensitive film in the rubbed part was What became 2/3 or less of the non-friction part

[Sharpness of image]
The obtained lithographic printing plate precursors 1 to 9 of the present invention and the lithographic printing plate precursors 10 and 11 of the comparative examples were drawn in a test pattern (Staccato 10) in an image shape with a Trend setter manufactured by Creo at a beam intensity of 9 w and a drum rotation speed of 150 rpm. I did. Fuji Photo Film Co., Ltd. was charged with the lithographic printing plate precursor 1-11 exposed under the above conditions and a developer DT-2 manufactured by Fuji Photo Film Co., Ltd. (DT-2: diluted with water = 1: 8). ) Using a PS processor 940HII manufactured, the liquid temperature was kept at 30 ° C., and development was performed for 12 seconds. The edge part of the obtained image was observed with an electron microscope (Hitachi S-800, manufactured by Hitachi, Ltd.). The image sharpness evaluation was performed according to the following criteria. The results are shown in Table 3 below.
<Evaluation criteria for scratch resistance>
○: The image has a straight side. Δ: The image has a part of the side that is slightly missing. X: The image has a half of the side.

  As is apparent from Table 3, Examples 1 to 9 in which a dispersed phase is formed in the lower layer and have a specific compound exhibit good scratch resistance with respect to Comparative Examples 1 and 2, and are excellent in development latitude. A sharp image was obtained.

It is a graph which shows an example of the alternating waveform current waveform figure used for the electrochemical roughening process in preparation of the support body used for the lithographic printing plate precursor of this invention. It is a side view which shows an example of the radial type cell in the electrochemical roughening process using alternating current in preparation of the support body for lithographic printing plates of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Aluminum plate 12 Radial drum roller 13a, 13b Main electrode 14 Electrolytic process liquid 15 Electrolyte supply port 16 Slit 17 Electrolyte passage 18 Auxiliary anode 19a, 19b Thyristor 20 AC power supply 40 Main electrolytic tank 50 Auxiliary anode tank

Claims (2)

A lithographic printing plate precursor comprising two or more positive-type recording layers containing a resin and an infrared absorber on a support and having increased solubility in an alkaline aqueous solution by infrared laser exposure,
Of the two or more positive recording layers, the positive recording layer closest to the support contains at least two resins, and at least one of these resins forms a dispersed phase, and naphtho A lithographic printing plate precursor comprising a compound selected from the group consisting of quinonediazide, benzoquinonediazide, and derivatives thereof.   2. The lithographic printing plate precursor as claimed in claim 1, wherein the dispersed phase contains a compound selected from the group consisting of the naphthoquinone diazide, benzoquinone diazide, and derivatives thereof.

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