JP2009085983A - Photosensitive lithographic printing plate precursor for infrared laser - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosensitive lithographic printing plate precursor for an infrared laser excellent in both chemical resistance and scratch resistance. <P>SOLUTION: The photosensitive lithographic printing plate precursor for an infrared laser has a lower layer containing a high molecular compound having a group represented by general formula (I) in a side chain and an infrared absorbent and an upper layer containing a water-insoluble and alkali-soluble resin in this order on a support having a hydrophilic surface, wherein Y represents an oxygen atom or -NH-; X represents an oxygen atom or a sulfur atom; and R represents H or a 1-3C alkyl group. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photosensitive lithographic printing plate precursor for infrared laser, and more specifically, a so-called direct lithographic photosensitive lithographic plate capable of direct plate making by scanning infrared laser light based on a digital signal of a computer or the like. It relates to the printing plate precursor.

  In recent years, the development of lasers has been remarkable, and in particular, solid-state lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared region have been increasing in output and size. Therefore, these lasers are very useful as an exposure light source when making a plate directly from digital data such as a computer.

  Infrared laser lithographic printing plate precursors that use an infrared laser having a light emitting region in the infrared region as an exposure light source generally contain a binder resin and an IR dye that absorbs light and generates heat as essential components. is there. Among such lithographic printing plate precursors for infrared lasers, those having a positive recording layer, when exposed to infrared laser, the IR dye and the like in the recording layer in the unexposed area (image area) By interacting, it acts as a dissolution inhibitor that substantially reduces the solubility of the binder resin. On the other hand, in the exposed portion (non-image portion), the IR dye or the like absorbs light and generates heat, so that the interaction between the IR dye and the binder resin is weakened. Therefore, at the time of development, the exposed portion (non-image portion) is dissolved and removed in an alkaline developer, whereby a lithographic printing plate is obtained.

In such a lithographic printing plate precursor for infrared laser, improvement in chemical resistance and improvement in scratch resistance are cited as technical problems. Among these, for improving chemical resistance, for example, it has been proposed to use polyvinyl acetal (see, for example, Patent Document 1), but this is insufficient from the viewpoint of achieving both chemical resistance and scratch resistance. In addition, it is considered that the resin layer structure of a lithographic printing plate precursor having two or more layers is useful for achieving both chemical resistance and scratch resistance. For example, a polymer having a maleimide compound as a constituent component in a lower layer Although it has been proposed to use a compound (see, for example, Patent Document 2), further level-up has been desired.
US Published Patent No. 2004/0020484 US Published Patent No. 2004/0067432

  An object of the present invention is to provide a photosensitive lithographic printing plate precursor for infrared laser which is excellent in both chemical resistance and scratch resistance.

  As a result of diligent research, the present inventor has found that the above problems can be solved by the following photosensitive lithographic printing plate precursor for infrared laser, and has completed the present invention.

  That is, the photosensitive lithographic printing plate precursor for infrared laser of the present invention comprises, on a support having a hydrophilic surface, a polymer compound having a group represented by the following general formula (I) in the side chain, and an infrared absorber. It has a lower layer containing and an upper layer containing a water-insoluble and alkali-soluble resin in this order.

In general formula (I), Y represents an oxygen atom or -NH-,
X represents an oxygen atom or a sulfur atom,
R represents H or an alkyl group having 1 to 3 carbon atoms.

  Here, “having in this order” means that at least the lower layer and the upper layer are provided in this order on a support having a hydrophilic surface, and other layers (for example, undercoat) provided as desired. It does not deny the existence of a layer.

  ADVANTAGE OF THE INVENTION According to this invention, the photosensitive lithographic printing plate precursor for infrared lasers excellent in both chemical resistance and scratch resistance can be provided.

[Photosensitive lithographic printing plate precursor for infrared laser]
Hereinafter, the photosensitive lithographic printing plate precursor for infrared laser of the present invention will be described in detail.
The photosensitive lithographic printing plate precursor for infrared laser of the present invention (hereinafter sometimes simply referred to as “lithographic printing plate precursor”) is a group represented by the following general formula (I) on a support having a hydrophilic surface. And a lower layer containing an infrared absorbent and an upper layer containing a water-insoluble and alkali-soluble resin. It is characterized by having in this order.

In general formula (I), Y represents an oxygen atom or -NH-,
X represents an oxygen atom or a sulfur atom,
R represents H or an alkyl group having 1 to 3 carbon atoms.

  The lithographic printing plate precursor according to the invention exhibits an excellent effect in both chemical resistance and scratch resistance by having the above-described configuration. The reason for this is not yet clear, but the improvement in chemical resistance in the present invention is achieved by containing a specific polymer compound in the lower layer and further providing an upper layer covering the lower layer, thereby slowing the penetration of the solvent. Presumably because it was made. For improving scratch resistance, the recording layer of the lithographic printing plate precursor according to the present invention is composed of two or more resin layers, and a high-strength film can be formed in the lower layer of the resin layer. It is presumed that the strength of the entire resin layer was increased by including such a specific polymer compound. This is considered to be due to the fact that the intermolecular hydrogen bond and the like are strengthened by having the general formula (I) in the side chain. Hereafter, each element which comprises the lithographic printing plate precursor of this invention is demonstrated sequentially.

[Lower layer containing specific polymer compound and infrared absorber]
The lower layer in the lithographic printing plate precursor according to the invention is a layer provided closer to the support than the upper layer described later, and contains a specific polymer compound and an infrared absorber.

(Specific polymer compound)
The specific polymer compound in the present invention is a polymer compound having a group represented by the following general formula (I) in the side chain.

In general formula (I), Y represents an oxygen atom or -NH-,
X represents an oxygen atom or a sulfur atom,
R represents H or an alkyl group having 1 to 3 carbon atoms.

In the general formula (I), specific examples of R include H, CH ₃ , C ₂ H ₅ , i-C ₃ H ₇ , and n-C ₃ H _7. Particularly preferable R is H It is.
Preferred X is an oxygen atom.

In general formula (I) -Y- is even in the main chain side, -SO ₂ - may be in the main chain side.
As the terminal structure of the side chain, an optionally substituted alkyl group having 1 to 12 carbon atoms, an optionally substituted aryl group having 2 to 15 carbon atoms, and an optionally substituted carbon group having 3 to 3 carbon atoms. It can be arbitrarily selected from 18 alkylaryl groups and optionally substituted arylalkyl groups having 3 to 18 carbon atoms. Among these, preferred are an optionally substituted alkyl group having 2 to 6 carbon atoms, an optionally substituted aryl group having 2 to 10 carbon atoms, and an optionally substituted carbon group having 4 to 12 carbon atoms. An alkylaryl group, and an optionally substituted arylalkyl group having 4 to 12 carbon atoms.

  Preferred substituents of the above-mentioned side chain terminal structure are halogen, hydroxy group, and carboxyl group, and particularly preferred substituents are n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, phenyl. , P-methylphenyl, p-hydroxyphenyl, phenylmethyl.

  In the specific polymer compound, the group represented by the general formula (I) may be included in the same molecule, or one or more types may be included in the same molecule. .

  The specific polymer compound of the present invention can be obtained by polymerizing a polymerizable monomer having a group represented by the general formula (I) in the side chain as a single component or copolymerizing with other components.

The polymerizable monomer having the group represented by the general formula (I) in the side chain can be obtained mainly by the following two methods.
One is obtained by reacting a polymerizable monomer having an OH group at a terminal with a compound having a sulfonyl isocyanate group. In this case, Y is O.
The other is obtained by reacting a polymerizable monomer having an isocyanate group at a terminal with a compound having a sulfonamide group, in which case Y is NH.

  Both the compound having a sulfonyl isocyanate group and the compound having a sulfonamide group preferably have a form in which these groups are bonded to an alkyl skeleton or an aryl skeleton. In the case of an alkyl skeleton, an alkyl group having 1 to 6 carbon atoms is preferable, and a t-butyl group is particularly preferable. In the case of an aryl skeleton, a phenyl group having a substituent and a naphthyl group having a substituent are preferable, and a p-methylphenyl group is particularly preferable.

  Examples of the polymerizable monomer having a side chain of the general formula (I) are shown below.

Moreover, you may copolymerize arbitrary polymerizable monomers other than the polymerizable monomer which has a side chain of general formula (I). Other components are not particularly specified as long as they are monomers that can be copolymerized with the components of the polymer compound used in the present invention, but (meth) acrylic acid esters, (meth) acrylonitriles, styrenic compounds, maleimides, Examples thereof include vinyl acetate and vinyl alcohol.
When the other components are copolymerized, the ratio of the polymerizable monomer having a side chain of the general formula (I) in the polymer compound is preferably 5 to 90 mol%, more preferably 10 to 70 mol%.
Examples of the polymer compound used in the present application are shown below.

  As a weight average molecular weight of a specific molecular compound, 1000 or more are preferable and 1000-300000 are more preferable.

  Only 1 type may be sufficient as the specific molecular compound contained in a lower layer, and it may use 2 or more types together.

  It is preferable that a specific high molecular compound is contained in the ratio of 10-99 mass% in the total solid contained in a lower layer.

  In addition, when a specific high molecular compound is contained in the lower layer in the ratio of 10-30 mass%, it is preferable to use together the other high molecular compound mentioned later with a specific high molecular compound from the point of film property.

(Infrared absorber)
The lower layer in the present invention contains an infrared absorber. The infrared absorber used here is not particularly limited as long as it is a pigment or dye that has an absorption maximum at a wavelength of 750 nm to 1,400 nm and absorbs light of this wavelength to generate heat, and an infrared absorbing pigment, Various pigments or dyes known as infrared absorbing dyes can be used.

As the infrared absorber, known various pigments and dyes are preferably exemplified. Examples of the pigment include a commercially available pigment and color index (CI) manual, “Latest Pigment Handbook” (edited by the Japan Pigment Technical Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “ Examples thereof include pigments described in "Printing Ink Technology", published by CMC Publishing, 1984).
Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bonded dyes. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments Quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like.

The pigment may be used without being subjected to a surface treatment or may be used after being subjected to a 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 (for example, silane coupling agent, epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The surface treatment method is described in “Characteristics and Application of Metal Soap” (Sachibo), “Printing Ink Technology” (CMC Publishing, 1984) and “Latest Pigment Application Technology” (CMC Publishing, 1986). .
The particle diameter of the pigment is preferably 0.01 to 10 μm, more preferably 0.05 to 1 μm, and particularly preferably 0.1 to 1 μm. When the particle size of the pigment is less than 0.01 μm, it may be undesirable from the viewpoint of stability of the dispersion in the photosensitive layer coating solution. On the other hand, when the particle size exceeds 10 μm, the photosensitive layer is uniform. It is not preferable in terms of sex.

  As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, or the like can be used. For the dispersion, a disperser such as 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, or a pressure kneader is used. Details are described in "Latest Pigment Applied Technology" (CMC Publishing, 1986).

  Examples of the dye include commercially available dyes and known dyes described in the literature (for example, “Dye Handbook” edited by the Society of Synthetic Organic Chemistry, published in 1970). For example, azo dyes, metal complex azo dyes, pyrazolone azo dyes. And dyes such as dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. Among the pigments or dyes, pigments and dyes that absorb infrared light or near infrared light are particularly preferable because they are suitable for use in lasers that emit infrared light or near infrared light.

  Carbon black is preferably used as the pigment that absorbs the infrared light or near infrared light. Examples of the dye that absorbs the infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-78787. Cyanine dyes described in JP-A Nos. 58-173696, 58-181690, 58-194595, etc., and 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, squarylium dyes described in JP-A-58-112792, and cyanine dyes described in British Patent 434,875.

  Further, as the dye, a near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and a substituted aryl described in US Pat. No. 3,881,924 is also used. Benzo (thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59 No. 41363, 59-84248, 59-84249, 59-146063, 59-146061, and pyranyl compounds described in JP-A-59-216146. And pentamethine thiopyrylium salts described in US Pat. No. 4,283,475, and Japanese Patent Publications Nos. 5-13514 and 5-19702. Pyrylium compounds disclosed, Epolight III-178, Epolight III-130, Epolight III-125, Epolight V-176A or the like is used particularly preferably.

  Moreover, as said dye, as another especially preferable example, the near-infrared absorptive dye described as U.S. Pat. No. 4,756,993 as the formulas (I) and (II) can be mentioned. The amount of the pigment or dye added is preferably 0.01 to 50% by weight, more preferably 0.1 to 10% by weight, based on the total solid content of the printing plate material. In the case of the dye, 0.5 to 10% by weight is particularly preferable, and in the case of a pigment, 3.1 to 10% by weight is particularly preferable. When the amount of the pigment or dye added is less than 0.01% by weight, the sensitivity may be low. On the other hand, when it exceeds 50% by weight, the uniformity of the photosensitive layer is lost, and Durability may deteriorate.

(Other polymer compounds)
In the lower layer in the present invention, in addition to the specific polymer compound described above, other polymer compounds can be used in combination. The polymer compound used in combination may be one type or two or more types. Moreover, although a high molecular compound is used for the upper layer, two or more types of high molecular compounds may be used. Here, these polymer compounds are described.

  Other polymer compounds that can be used in the present invention are preferably polymer compounds that are soluble or swellable in an alkaline aqueous solution. Such a high molecular compound is a high molecular compound different from the specific high molecular compound, and has an acidic group listed in (1) to (6) below in the main chain and / or side chain of the polymer. Mention may be made of molecular compounds.

(1) Phenol group (-Ar-OH)
(2) Sulfonamide group (—SO ₂ NH—R ^A )
(3) Substituted sulfonamide acid group (hereinafter referred to as “active imide group”)
[—SO ₂ NHCOR ^A , —SO ₂ NHSO ₂ R ^A , —CONHSO ₂ R ^A ]
(4) Carboxylic acid group (—CO ₂ H)
(5) Sulfonic acid group (—SO ₃ H)
(6) Phosphate group (—OPO ₃ H ₂ )

In the acidic groups listed as (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R ^A is a hydrocarbon group which may have a substituent. Represents.

  Examples of the polymer compound having an acidic group selected from (1) to (6) include the following.

  (1) Examples of the polymer compound having a phenol group include novolak resins, xylenol resins, and resole resins. Specifically, phenol formaldehyde resins, m-cresol formaldehyde resins, p-cresol formaldehyde resins, m // p-mixed cresol formaldehyde resin, phenol / cresol (m-, p-, o-, m- / p-mixed, m- / o-mixed and o- / p-mixed) mixed formaldehyde resin, 1,2-xylenol, 1,3-xylenol, 1,4-xylenol, 1,5-xylenol, 2,3-xylenol, 2,4-xylenol resin, xylenol / phenol mixed resin, xylenol / novolak mixed resin, xylenol / Novolac / Phenol mixed resin and Pi Mention may be made of the condensation polymers of Garoru and acetone. In addition, a polymer compound obtained by copolymerizing a compound having a phenol group in the side chain can also be mentioned, and acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, or hydroxystyrene having a phenol group can be used as a copolymer component. High molecular compounds.

    (2) As a polymer compound having a sulfonamide group, for example, a polymer composed of a minimum structural unit derived from a compound having a sulfonamide group as a main constituent can be mentioned. Examples of the compound as described above include compounds having at least one sulfonamide group in which at least one hydrogen atom is bonded to a nitrogen atom and one or more polymerizable unsaturated groups in the molecule. Of these, low molecular weight compounds having an acryloyl group, an allyl group, or a vinyloxy group and a substituted or monosubstituted aminosulfonyl group or a substituted sulfonylimino group in the molecule are preferable. For example, the following general formulas (i) to ( and a compound represented by v).

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

  Among the compounds represented by the general formula (i) to the general formula (v), in the multilayer sensitive material type printing plate precursor of the present invention, in particular, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacryl Amide, N- (p-aminosulfonylphenyl) acrylamide and the like can be preferably used.

  (3) As a high molecular compound which has an active imide group, the polymer comprised as a main structural component the minimum structural unit derived from the compound which has an active imide group can be mentioned, for example. Examples of the compound as described above include compounds having one or more active imide groups represented by the following structural formula and polymerizable unsaturated groups in the molecule, respectively. N- (p-toluenesulfonyl) ) Methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

(4) As a high molecular compound having a carboxylic acid group, for example, a minimum structural unit derived from a compound having at least one carboxylic acid group and one or more polymerizable unsaturated groups in the molecule is used as a main constituent component. A polymer can be mentioned. Acrylic acid, methacrylic acid, maleic acid, and itaconic acid can be particularly preferably used in the multilayer sensitive material type printing plate precursor of the present invention.
(5) As a high molecular compound having a sulfonic acid group, for example, a minimum structural unit derived from a compound having at least one sulfonic acid group and polymerizable unsaturated group in the molecule is used as a main structural unit. A polymer can be mentioned.
(6) As a high molecular compound having a phosphoric acid group, for example, a minimum structural unit derived from a compound having at least one phosphoric acid group and a polymerizable unsaturated group in the molecule is used as a main constituent component. A polymer can be mentioned.

  In addition to the above, a polymer using an unsaturated compound having an acidic group of (1) to (6) in the side chain and a urea bond as a linking group can also be used.

  Among the polymer compounds having an acidic group selected from (1) to (6), a polymer having (1) a phenol group, (2) a sulfonamide group, (3) an active imide group, and (4) a carboxylic acid group. A compound is preferred, and in particular, a polymer compound having (1) a phenol group, (2) a sulfonamide group or (4) a carboxylic acid group is most preferred.

  Further, the minimum structural unit having an acidic group selected from (1) to (6) is not particularly limited to one kind, and two or more minimum structural units having the same acidic group are used, or different acidic groups are used. What copolymerized 2 or more types of the minimum structural unit which has can also be used.

  In the case where the polymer compound is a copolymer, it is preferable that a compound having an acidic group selected from (1) to (6) to be copolymerized is contained in an amount of 3 mol% or more in the copolymer. % Is more preferable. If it is less than 3 mol%, the solubility in an alkaline developer containing substantially no solvent will decrease.

As the monomer component to be copolymerized with the polymerizable monomer having an acidic group, for example, monomers listed in the following (m1) to (m11) can be used, but are not limited thereto.
(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-phenylmaleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, N- (p-chlorobenzoyl) methacrylamide.

  As described above, among the other polymer compounds mentioned as examples, the other polymer compound used in combination with the specific polymer compound in the lower layer is preferably a copolymer having a sulfonamide group and / or a carboxylic acid group. Examples of the copolymer component include alkyl (meth) acrylate, (meth) acrylamide, (meth) acrylonitrile, and N-phenylmaleimide.

Of the polymer compounds exemplified above, the polymer compound used in the lower layer is preferably a copolymer having a sulfonamide group and / or a carboxylic acid group. ) Acrylate, (meth) acrylamide, (meth) acrylonitrile, N-phenylmaleimide.
In addition, as other polymer compounds used in the lower layer, novolac resins are also preferably used, such as phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / Cresol (m-, p-, o-, m- / p-mixed, m- / o-mixed and o- / p-mixed) mixed formaldehyde resin. Two or more polymer compounds may be used in combination.

When the polymer compound used in the lower layer of the present invention is a resin such as phenol formaldehyde resin or cresol aldehyde resin, the weight average molecular weight is 500 to 20,000, and the number average molecular weight is 200 to 10,000. Those are preferred. In the case of other polymer compounds, those having a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more are preferred, more preferably a weight average molecular weight of 5,000 to 300,000, Is 800 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10.
In the present invention, the total amount of the polymer compound added is 30 to 99% by weight, preferably 50 to 99% by weight, particularly preferably 65 to 99% by weight. When the addition amount of the polymer compound is less than 30% by weight, the durability of the heat-sensitive layer deteriorates. When the addition amount exceeds 99% by weight, particularly in the case of the lower layer, the addition amount of the infrared absorber described later decreases, and the sensitivity. Is unfavorable because of lowering.

(Other ingredients)
Various additives can be further added to the coating layer such as the lower layer according to the present invention as necessary.

  For example, in order to adjust the solubility of the lower layer, it is preferable to add a dissolution inhibitor such as onium salt, aromatic sulfone compound, aromatic sulfonic acid ester compound, polyfunctional amine compound, etc. -The use of a substance that is thermally decomposable, such as a quinonediazide compound and a sulfonic acid alkyl ester, and that substantially reduces the solubility of the alkali-soluble resin in a state where it does not decompose can prevent the dissolution of the image area in the developer. It is preferable in that it can be controlled. As the onium salt, a diazonium salt and a quaternary ammonium salt are particularly preferable.

  Preferred examples of the onium salt used in the present invention include S.P. I. Schlesinger, Photogr. Sci. Eng. 18, 387 (1974), T .; S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, and JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; 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 salts, J.M. V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. 43, 3055 (1978); R. Watt et al, J.A. Polymer Sci. , 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, J.A. Polymer Sci. , 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. 5,041,358, No. 4,491,628, 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, J.A. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988).

  Among these onium salts, diazonium salts and quaternary ammonium salts are particularly preferable from the viewpoints of dissolution inhibition ability and thermal decomposability. In particular, the diazonium salt is preferably a diazonium salt represented by the general formula (I) described in JP-A-5-158230 or a diazonium salt represented by the general formula (1) described in JP-A-11-143064. The diazonium salt represented by the general formula (1) described in JP-A-11-143064 having a small absorption wavelength in the visible light region is most preferable. Moreover, as a quaternary ammonium salt, the quaternary ammonium salt shown by (1)-(10) in [Chemical 5] [Chemical 6] described in Unexamined-Japanese-Patent No. 2002-229186 is preferable.

  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.

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

  Further, an ester of naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and phenol formaldehyde resin or cresol-formaldehyde resin, naphthoquinone- (1,2) -diazido-4-sulfonic acid chloride and pyrogallol-acetone resin Similarly, the esters are also preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, JP-A-48-96575, JP-A-49-38701, JP-A-48-13354, Japanese Patent Publication Nos. 41-11222, 45-9610, 49-17474, U.S. Pat. Nos. 2,797,213, 3,454,400, 3,544,323, 3,573,917, 3,674,495, 3,785,825, British Patents 1,227,602, 1,251,345, 1,267, No. 005, No. 1,329,888, No. 1,330,932, German Patent No. 854,890, and the like.

The amount of the onium salt and / or o-quinonediazide compound that is a degradable dissolution inhibitor is preferably 1 to 10% by mass, more preferably 1 to 5% by mass, particularly preferably the total solid content of the recording layer. Is in the range of 1-2% by weight. These compounds can be used alone, but may be used as a mixture of several kinds.
The amount of additives other than the o-quinonediazide compound is preferably 0.1 to 5% by mass, more preferably 0.1 to 2% by mass, and particularly preferably 0.1 to 1.5% by mass. The additive and binder according to the present invention are preferably contained in the same layer.

Further, a dissolution inhibitor having no decomposability may be used in combination, and preferred dissolution inhibitors include sulfonate esters, phosphate esters, and aromatic carboxylic acids described in detail in JP-A-10-268512. Esters, aromatic disulfones, carboxylic anhydrides, aromatic ketones, aromatic aldehydes, aromatic amines, aromatic ethers, etc., as well as lactone skeletons described in detail in JP-A-11-190903, N, N- Examples thereof include an acid color-forming dye having a diarylamide skeleton and a diarylmethylimino skeleton, which also serves as a colorant, and nonionic surfactants described in detail in JP-A No. 2000-105454.
Moreover, in the photosensitive composition of this invention, cyclic acid anhydrides, phenols, and organic acids can be used together for the purpose of improving a sensitivity. Further, a surfactant, an image colorant, and a plasticizer described later can also be used in the positive recording layer of the present invention.

Examples of cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, 3,6-endooxy-4-tetrahydrophthalic anhydride, tetrachlorophthalic anhydride described in US Pat. No. 4,115,128, 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. Examples thereof include sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphate esters, and carboxylic acids described in JP-A-60-88942 and JP-A-2-96755.
The proportion of the cyclic acid anhydride, phenols, and organic acids in the recording layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, particularly preferably 0.1 to 0.1% by mass. 10% by mass.

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

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

  As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (oriental chemical industry) Manufactured by Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred. These dyes can be added to the recording layer in a proportion of 0.01 to 10% by mass, preferably 0.1 to 3% by mass, based on the total solid content of the recording layer.

  Furthermore, a plasticizer is added to the photosensitive composition 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.

[Coating solvent and coating method]
The recording layer can be produced by dissolving the photosensitive composition of the present invention in a solvent and coating it on a suitable support. Further, depending on the purpose, a protective layer, a resin intermediate layer, a backcoat layer and the like, which will be described later, can be formed in the same manner.

  Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene and the like. It is not limited to. 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. Further, the solid coating amount on the support obtained after coating and drying is preferably 0.05 to 2.0 g / m 2 for the upper layer and 0.3 to 5.0 g / m 2 for the lower layer, more preferably 0 for the upper layer. 0.1 to 1.0 g / m 2, and the lower layer is in the range of 0.5 to 3.0 g / m 2. Moreover, 0.05-1 are preferable and, as for ratio of the coating amount of an upper layer and a lower layer, More preferably, it is the range of 0.1-0.8.
Various methods can be used as a method for applying the recording layer coating liquid. For example, bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, roll coating, etc. Can be mentioned. As the coating amount decreases, the apparent sensitivity increases, but the film properties of the photosensitive film deteriorate.

  In addition, a dissolution inhibitor having no decomposability may be used in combination, such as sulfonic acid ester, phosphoric acid ester, aromatic carboxylic acid ester, aromatic disulfone, carboxylic acid anhydride, aromatic ketone, aromatic aldehyde, aromatic Examples thereof include amines and aromatic ethers.

  Furthermore, for the purpose of improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be used in the lower layer together with surfactants, image colorants, and a visible image immediately after heating by exposure. Bakeout agents and plasticizers can also be used.

[Upper layer containing water-insoluble and alkali-soluble resin]
The upper layer in the present invention is characterized by containing a water-insoluble and alkali-soluble resin (hereinafter, appropriately referred to as “alkali-soluble resin”). Hereafter, each component which the upper layer in this invention contains is demonstrated.

(Water-insoluble and alkali-soluble resin)
The alkali-soluble resin that can be used for the upper layer is not particularly limited as long as it has a property of dissolving when contacted with an alkaline developer, but a monomer containing an acidic group in the main chain and / or side chain in the polymer. Is preferably a homopolymer obtained from the above, a copolymer thereof, or a mixture thereof.

  As such an alkali-soluble resin having an acidic group, in particular, a polymer compound having a functional group in any one of (1) a phenolic hydroxyl group, (2) a sulfonamide group, and (3) an active imide group. Can be mentioned. For example, although the following are illustrated, this invention 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 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 phenolic hydroxyl group and at least one polymerizable unsaturated bond is homopolymerized, or other polymerization is performed on the monomer. And a high molecular compound obtained by copolymerizing a functional monomer.

  Examples of the polymerizable monomer having a phenolic hydroxyl group include acrylamide, methacrylamide, acrylic ester, methacrylic 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-hydroxy Phenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) Preferable are til acrylate, 2- (4-hydroxyphenyl) ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate, 2- (4-hydroxyphenyl) ethyl methacrylate, etc. Can be used. Such resins having a phenolic hydroxyl group may be used in combination of two or more. Furthermore, 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, These copolymers may be used in combination.

(2) Examples of the alkali-soluble resin having a sulfonamide group include polymer compounds 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 resin having an active imide group is preferably one having an active imide group in the molecule, and the polymer compound has one unsaturated bond polymerizable with the active imide group in each molecule. Examples thereof include a polymer compound obtained by homopolymerizing a polymerizable monomer comprising the above-described low molecular weight compound, or 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.

  The alkali-soluble resin contained in the upper layer is a polymer compound obtained by polymerizing two or more of a polymerizable monomer having a phenolic hydroxyl group, a polymerizable monomer having a sulfonamide group, and a polymerizable monomer having an active imide group. Preferably there is. Although there is no restriction | limiting in the copolymerization ratio of the said polymerizable monomer, and the combination of a polymerizable monomer, Especially the polymerizable monomer which has a sulfonamide group in the polymerizable monomer which has a phenolic hydroxyl group, and / or the polymerizable property which has an active imide group When monomers are copolymerized, the compounding polymerization ratio of these components is preferably in the range of 50:50 to 5:95, and particularly preferably in the range of 40:60 to 10:90.

  When the alkali-soluble resin contained in the upper layer is a homopolymer or 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, the weight average molecular weight Are preferably 2,000 or more and a number average molecular weight of 500 or more. More preferably, the weight average molecular weight is 5,000 to 300,000, the number average molecular weight is 800 to 250,000, and the dispersity (weight average molecular weight / number average molecular weight) is 1.1 to 10. .

  In particular, when the alkali-soluble resin contained in the upper layer is a phenol formaldehyde resin or a cresol aldehyde resin, the weight average molecular weight is 500 to 20,000, and the number average molecular weight is 200 to 10,000. Is preferred.

  As the alkali-soluble resin contained in the upper layer, a resin having a phenolic hydroxyl group is desirable in terms of causing strong hydrogen bonding in the unexposed area and easily releasing some hydrogen bonds in the exposed area. Among the resins having a functional hydroxyl group, a novolak resin is particularly preferable. In the present invention, two or more kinds of alkali-soluble resins having different dissolution rates in an alkaline aqueous solution may be mixed and used, and the mixing ratio in that case is arbitrary. The alkali-soluble resin suitable for mixing with the resin having a phenolic hydroxyl group is preferably an acrylic resin because of its low compatibility with a resin having a phenolic hydroxyl group, and more preferably a sulfoamide group. It is an acrylic resin.

  The content of the alkali-soluble resin in the total solid content of the upper layer is preferably in the range of 50 to 98% by mass from the viewpoint of the sensitivity and durability of the recording layer. In addition, this content points out the total amount, when using together multiple types of alkali-soluble resin.

  An infrared absorber can be added to the upper layer. The infrared absorber is not particularly limited as long as it has an absorption maximum from a wavelength of 750 nm to 1,400 nm and absorbs light of this wavelength and generates heat, and various dyes known as infrared absorbing dyes can be used. Specifically, the same materials as those mentioned as the infrared absorber used in the lower layer can be used.

  As content of the infrared absorber in an upper layer, it is preferable that it is 0.01-50 mass% in the total solid of an upper layer, More preferably, it is 0.1-30 mass%, Most preferably, it is 1.0-30. It is the range of mass%. By setting it in the above range, the sensitivity becomes better, and the uniformity and durability of the upper layer (upper recording layer) become better.

  The upper layer preferably contains a development inhibitor for the purpose of increasing its inhibition (dissolution inhibiting ability).

  As a development inhibitor, it forms an interaction with the alkali-soluble resin contained in the upper layer, substantially lowers the solubility of the alkali-soluble resin in the developer in the unexposed area, and in the exposed area There is no particular limitation as long as the interaction is weakened and can be soluble in the developer, but quaternary ammonium salts, polyethylene glycol compounds and the like are particularly preferably used. In addition, when the compound which has a function of a development inhibitor is used as an infrared absorber, it is not necessary to add a development inhibitor.

  Examples of quaternary ammonium salts include tetraalkylammonium salts, trialkylarylammonium salts, dialkyldiarylammonium salts, alkyltriarylammonium salts, tetraarylammonium salts, cyclic ammonium salts, and bicyclic ammonium salts. Polyethylene glycol compounds include polyethylene glycols, polypropylene glycols, polyethylene glycol alkyl ethers, polypropylene glycol alkyl ethers, polyethylene glycol aryl ethers, polypropylene glycol aryl ethers, polyethylene glycol alkyl aryl ethers, polypropylene glycol alkyl. Aryl ethers, polyethylene glycol glycerol esters, polypropylene glycol glycerol esters, polyethylene sorbitol esters, polypropylene glycol sorbitol esters, polyethylene glycol fatty acid esters, polypropylene glycol fatty acid esters, polyethylene glycolated ethylenediamine , Polypropylene glycolated ethylenediamines, polyethylene glycolated diethylenetriamine, and polypropylene glycol diethylenetriamines.

  In addition, substances that are thermally decomposable, such as onium salts, o-quinonediazide compounds, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, and that substantially reduce the solubility of alkali-soluble resins when not decomposed. Is preferably used from the viewpoint of improving the inhibition of the image portion in the developer.

  Examples of onium salts that can be used in the present invention include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts, and the like, and among these, diazonium salts are particularly preferable. Particularly suitable diazonium salts include those described in JP-A-5-158230.

Suitable quinonediazides include o-quinonediazide compounds.
The amount of these added is preferably in the range of 0.1 to 10% by mass, and more preferably in the range of 0.5 to 5% by mass in the total solid content of the upper layer.

  In forming the upper layer, in addition to the above-described components, various additives can be added as long as the effects of the present invention are not impaired.

  For example, acid anhydrides, phenols, and organic acids may be added for the purpose of improving sensitivity, and nonionic surfactants and amphoteric surfactants are used to improve coatability and improve processing stability against development conditions. Agents, siloxane compounds, and fluorine-containing monomer copolymers can be added. Baking agents for obtaining a visible image immediately after heating by exposure and dyes and pigments as image colorants can be added. Further, a plasticizer may be added to impart flexibility and the like of the coating film.

  The upper layer can usually be formed by dissolving the above components in a solvent and coating, but preferably the one that does not dissolve the lower layer as much as possible. Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Mention may be made of ethane, methyl lactate, ethyl lactate, toluene and the like. These solvents are used alone or in combination.

Further, the coating amount of the upper layer obtained after coating and drying the upper layer coating solution on the support is preferably in the range of 0.05 to 2.0 g / m ² , more preferably 0.8. The range is 1 to 1.0 g / m ² .

[Support]
The support in the lithographic printing plate precursor according to the invention is not particularly limited as long as it is a dimensionally stable plate-like material and satisfies physical properties such as required strength and flexibility. As the support, for example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, triacetic acid, etc.) Cellulose, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), metal laminated or vapor deposited paper, plastic film Can be mentioned.

  As a support that can be applied to a lithographic printing plate precursor, 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.

  The composition of the aluminum plate applicable to the present invention is not specified, and an aluminum plate made of a publicly known material can be used as appropriate. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.12 mm to 0.4 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 Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can also be used. Among these, it is preferable to include a step of roughening at least in a hydrochloric acid electrolyte.

The roughened aluminum plate is subjected to alkali etching treatment and neutralization treatment as necessary, and then subjected to anodization treatment if desired in order to enhance the water retention and wear resistance of the surface. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte. The treatment conditions for anodization vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. A voltage of 1 to 100 V and an electrolysis time of 10 seconds to 5 minutes are suitable. When the amount of the anodized film is less than 1.0 g / m ² , the printing durability is insufficient, or the non-image portion of the planographic printing plate is easily damaged, and the ink adheres to the damaged portion during printing. So-called “scratch stains” easily occur.

  After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary. 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 US Pat. Nos. 3,276,868, 4,153,461, and 4,689,272. A method of treating with polyvinylphosphonic acid is used.

The lithographic printing plate precursor according to the present invention is provided with a recording layer having a multi-layer structure including the upper layer and the lower layer as described above on the support, and if necessary, between the support and the lower layer, Further, an undercoat layer can be provided. By providing this undercoat layer, the undercoat layer between the support and the recording layer functions as a heat insulating layer, and the heat generated by the infrared laser exposure does not diffuse to the support and can be used efficiently. Therefore, there is an advantage that high sensitivity can be achieved. Various organic compounds are used as the primer layer component, such as carboxymethylcellulose, dextrin, gum arabic, phosphonic acids having amino groups, organic phosphonic acids, organic phosphoric acids such as phenylphosphoric acid, organic phosphinic acids, amino acids And a hydrochloride of an amine having a hydroxy group, and a polymer compound having a component having an acid group and a component having an onium group described in JP-A No. 2000-241962. The coverage of the undercoat layer is in terms of printing durability, 2 to 200 mg / m ² are suitable, and preferably from 5 to 100 mg / m ^2.

-Prepress processing of lithographic printing plate precursors-
〔exposure〕
The lithographic printing plate precursor according to the invention is image-formed by heat. Specifically, an image is formed by scanning exposure using a solid-state high-power infrared laser such as a semiconductor laser or a YAG laser that emits infrared light having a wavelength of 700 to 1200 nm. The planographic printing plate precursor of the present invention can also form an image by direct image-like recording using a thermal recording head or the like, high-illuminance flash exposure such as a xenon discharge lamp, or infrared lamp exposure.

The output of the infrared laser is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec, and the energy irradiated to the recording material is preferably 10 to 500 mJ / cm ² .

〔developing〕
The exposed lithographic printing plate precursor is preferably developed with an alkaline aqueous solution having a pH of 12 or higher that does not substantially contain an organic solvent. Here, “substantially free of organic solvent” means that it does not contain an organic solvent to the extent that it causes inconvenience in terms of environmental health, safety, workability, etc. The ratio of the organic solvent in the developer is 0.5% by weight or less, preferably 0.3% by weight or less, and most preferably not contained at all. Moreover, although pH is 12.0 or more, More preferably, it is 12.0-14.0.

  A conventionally known alkaline aqueous solution can be used as the developer (hereinafter referred to as developer including the replenisher). For example, sodium silicate, potassium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium bicarbonate, potassium, Examples thereof include inorganic alkali salts such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. Moreover, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkali agents such as ethyleneimine, ethylenediamine, and pyridine are listed. These alkaline aqueous solutions may be used individually by 1 type, and may use 2 or more types together.

  Among the above alkaline aqueous solutions, one of the developing solutions that exert the effect according to the present invention is a so-called one containing an alkali silicate as a base, or containing an alkali silicate by mixing a silicon compound with a base. An aqueous solution having a pH of 12 or more called “silicate developer”, and another more preferable developer does not contain an alkali silicate but contains a non-reducing sugar (an organic compound having a buffering action) and a base. Non-silicate developer ".

  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, or improving ink affinity of the printing plate image area. . As the surfactant, anionic, cationic, nonionic and amphoteric surfactants are preferable. Further, the developer and replenisher may contain a reducing agent such as sodium salt and potassium salt of inorganic acids such as hydroquinone, resorcin, sulfurous acid, and bisulfite, as well as organic carboxylic acid, antifoaming agent, hard water, if necessary. Softeners and the like can be added.

  The lithographic printing plate precursor developed using a developer and a replenisher is post-treated with a desensitizing solution containing rinsing water containing a washing water, a surfactant and the like, gum arabic and starch derivatives. As post-processing, these processes can be used in various combinations.

  Further, when developing using an automatic developing machine, an aqueous solution (replenisher) having a higher alkali strength than that of the developer is added to the developer, so that a large amount of developer can be obtained without replacing the developer in the developer tank for a long time. It is known that PS plates can be processed. This replenishment method is also preferably applied in the present invention.

  The printing plate developed using the developer and the replenisher is post-treated with a desensitizing solution containing washing water, a rinsing solution containing a surfactant or the like, gum arabic or a starch derivative. As the post-treatment of the lithographic printing plate precursor using the photosensitive composition of the present invention, these treatments can be used in various combinations.

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

  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 make a lithographic printing plate with a higher printing durability, if desired, Burning process is performed. In the case of burning a lithographic printing plate, before burning, an adjustment as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, JP-A-61-159655 is used. It is preferable to treat with a surface liquid.

  The planographic printing plate obtained by such processing is applied to an offset printing machine or the like and used for printing a large number of sheets.

  EXAMPLES Hereinafter, although this invention is demonstrated according to an Example, the scope of the present invention is not limited to these Examples.

[Example 1]
(Production of support)
The support body was produced by processing through the process shown below using a JIS-A-1050 aluminum plate with a thickness of 0.3 mm.

The above aluminum plate was sprayed with an aqueous NaOH solution (concentration 26 mass%, aluminum ion concentration 6.5 mass%) at a temperature of 70 ° C. to dissolve the aluminum plate 6 g / m ² . Thereafter, washing with water was performed using well water.
Next, it was desmutted by spraying with a 1% by weight aqueous solution of nitric acid having a temperature of 30 ° C. (containing 0.5% by weight of aluminum ions), and then washed with water by spraying.
Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a hydrochloric acid 7.5 g / liter aqueous solution (containing 5 g / liter of aluminum ions) at a temperature of 35 ° C. The AC power supply waveform was a rectangular wave, and an electrochemical surface roughening treatment was performed using a carbon electrode as a counter electrode. Ferrite was used for the auxiliary anode. The electrolytic cell used was a radial cell type. The current density was 25 A / dm ² at the peak current value, and the amount of electricity was 450 C / dm ² in terms of the total amount of electricity when the aluminum plate was the anode.
Thereafter, washing with water was performed using well water.

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

Subsequently, desmutting treatment was performed by spraying with an aqueous solution having a sulfuric acid concentration of 25% by mass (containing 0.5% by mass of aluminum ions) at a temperature of 60 ° C., followed by washing with water using well water.
Next, an anodizing treatment was performed. The electrolytic solution had a sulfuric acid concentration of 170 g / liter (containing 0.5% by mass of aluminum ions) and a temperature of 43 ° C. Thereafter, washing with water was performed using well water. The current density was about 30A / dm ^2. The final oxide film amount was 2.7 g / m ² .

  Further, an anodized aluminum plate was immersed for 5 seconds in a solution obtained by heating a 0.5% polyvinylphosphonic acid aqueous solution to 60 ° C., and washed with water by spraying.

  As described above, a support used for the photosensitive lithographic printing plate precursor according to the example was obtained.

(Formation of the lower layer)
The lower layer coating liquid A having the following composition was applied to the support obtained above with a wire bar, and then dried for 50 seconds in a drying oven set at 140 ° C. to form a lower layer. The coating amount of the lower layer after drying was 1.2 g / m ² .

<Coating liquid A for lower layer>
・ High molecular compound (1)
(The compound described above as an exemplary compound, a / b = 70/30 (molar ratio),
Weight average molecular weight 60,000) 0.80 g
・ Cyanine dye P (the following structure) 0.15g

・エチルバイオレット ０．０５ｇ
・メチルエチルケトン ５．００ｇ
・１−メトキシ−２−プロパノール ５．００ｇ
・Ｎ，Ｎ−ジメチルホルムアミド １０．００ｇ

・ Ethyl violet 0.05g
・ Methyl ethyl ketone 5.00g
・ 1-methoxy-2-propanol 5.00g
・ N, N-dimethylformamide 10.00g

(Formation of upper layer)
On the lower layer formed as described above, an upper layer coating solution A having the following composition was coated with a wire bar, and then dried for 60 seconds in a drying oven set at 130 ° C. to obtain an upper layer. The coating amount of the upper layer after drying was 0.4 g / m ² .

<Upper layer coating liquid A>
-Novolak resin (weight average molecular weight 5,000) of m-cresol / p-cresol / phenol = 45/30/25 (molar ratio) 0.95 g
・ Cyanine dye P (the above structure) 0.05 g
・ Methyl ethyl ketone 10.00g
1-methoxy-2-propanol 10.00g

  In this way, a lithographic printing plate precursor (A) of Example 1 was obtained.

[Examples 2 to 6]
In Example 1, except that the above-described polymer compounds (2) to (7) were used as exemplary compounds of the specific polymer compound instead of the polymer compound (1) used for the formation of the lower layer, respectively. In the same manner as in Example 1, lithographic printing plate precursors (ii) to (ki) of Examples 2 to 6 were obtained.

The details of the polymer compound used are shown below.
Polymer compound (2) a / b / c = 30/60/10 (molar ratio)
Weight average molecular weight 50,000
Polymer compound (3) a / b / c = 40/50/10 (molar ratio),
Weight average molecular weight 80,000
Polymer compound (4) a / b / c = 35/35/30 (molar ratio),
Weight average molecular weight 70,000
Polymer compound (5) a / b / c = 10/60/30 (molar ratio),
Weight average molecular weight 30,000
Polymer compound (6) a / b / c / d = 20/15/45/20 (molar ratio),
Weight average molecular weight 40,000
Polymer compound (7) a / b / c = 15/25/60 (molar ratio),
Weight average molecular weight 50,000

[Example 8]
In Example 4, the addition amount of the polymer compound (4) used for forming the lower layer was changed to 0.40 g, and as other polymer compounds, novolak of m-cresol / p-cresol = 60/40 0.10 g of resin (weight average molecular weight 5,000), copolymer of N-phenylmaleimide / methacrylamide / acrylonitrile / N- (p-hydroxyphenyl) methacrylamide = 5/10/50/35 (molar ratio) A lithographic printing plate precursor (6) of Example 8 was obtained in the same manner as in Example 1, except that 0.30 g (weight average molecular weight 70,000) was added.

[Example 9]
In Example 4, the addition amount of the polymer compound (4) used for forming the lower layer was changed to 0.60 g, and as other polymer compounds, m-cresol / p-cresol = 60/40 novolak resin ( A lithographic printing plate precursor (Ke) of Example 9 was obtained in the same manner as in Example 1 except that 0.20 g of a weight average molecular weight of 5,000) was added.

[Comparative Example 1]
In Example 1, a copolymer of N-phenylmaleimide / methacrylamide / methacrylic acid = 45/35/20 (molar ratio) (weight average molecular weight 20) was used as the polymer compound instead of the polymer compound (1) in the lower layer. , 000) was used in the same manner as in Example 1 to obtain a lithographic printing plate precursor (ko) of Comparative Example 1.

[Comparative Example 2]
In Example 1, a lithographic printing plate precursor (SA) of Comparative Example 2 was obtained in the same manner as Example 1 except that no upper layer was provided.

<Evaluation of planographic printing plate precursor>
1. Evaluation of chemical resistance Each of the obtained lithographic printing plate precursors (A) to (SA) was 175 lpi / 2400 dpi halftone dot with a Trend setter 3244 manufactured by Creo under the conditions of a beam intensity of 10.0 W and a drum rotation speed of 250 rpm. Drawing (exposure) was performed on an image of a test pattern containing a chart with an area ratio of 1 to 99%.
Next, using a PS processor LP-940HII manufactured by FUJIFILM Corporation, a lithographic printing plate was obtained by performing a developing process and a gumming process at a developer temperature of 30 ° C. and a developing time of 12 seconds. At this time, as a developing solution, a solution obtained by diluting a developing solution “DT-2” manufactured by Fuji Film Co., Ltd. 1: 8 with water, and as a gum solution, “FG-” manufactured by Fuji Film Co., Ltd. is used. A solution obtained by diluting 1 ”with water 1: 1 was used.

  Printing was performed using the lithographic printing plate thus obtained. At this time, Lislon printing machine manufactured by Komori Corporation was used as the printing machine, “Barius G” ink ink manufactured by Dainippon Ink and Chemicals was used as ink, and Fuji Photo Film was used as dampening water. A solution obtained by diluting “IF-102” manufactured by Co., Ltd. with water to a concentration of 4% was used. Further, every time 5000 sheets were printed, the plate surface was wiped with a multi-cleaner manufactured by Fuji Film Co., Ltd. Printing durability was evaluated based on the number of printed sheets when printed on high-quality paper and visually recognized that the density of the solid image started to decrease. The larger the value, the better the chemical resistance. The results are shown in Table 1.

2. Evaluation of Scratch Resistance The obtained lithographic printing plate precursors (A) to (SA) were rubbed 15 times with an Ablaser felt CS5 to which a load of 250 g weight was applied using a rotary ablation tester manufactured by TOYOSEIKI.
Next, this plate was subjected to development processing by the same method as the evaluation of chemical resistance described above, using a solution obtained by diluting the developer “DT-2” 1: 8 with water as a developer.
For the plate thus obtained, the density of the plate surface was measured with a Macbeth densitometer on the part subjected to friction and the part not subjected to friction, and the absolute value of the difference was calculated. The results are shown in Table 1. The larger the value, the greater the damage to the plate due to friction.

As shown in Table 1, the lithographic printing plate precursors (A) to (K) of the examples have good chemical resistance, small concentration change values before and after friction, and good scratch resistance. It was the original edition.
On the other hand, the lithographic printing plate precursor of this comparative example containing no specific polymer compound in the lower layer was a lithographic printing plate precursor having poor chemical resistance, although there was no problem in scratch resistance. Further, the lithographic printing plate precursor (S) of Comparative Example 2 having no upper layer was a lithographic printing plate precursor inferior in both chemical resistance and scratch resistance.

  As shown in the above Examples, it can be seen that a lithographic printing plate precursor excellent in both chemical resistance and scratch resistance can be obtained by the present invention.

Claims (1)

On a support having a hydrophilic surface, a lower layer containing a polymer compound having a group represented by the following general formula (I) in the side chain and an infrared absorber, and an upper layer containing a water-insoluble and alkali-soluble resin In this order, a photosensitive lithographic printing plate precursor for an infrared laser.

In general formula (I), Y represents an oxygen atom or -NH-,
X represents an oxygen atom or a sulfur atom,
R represents H or an alkyl group having 1 to 3 carbon atoms.