JP5466719B2 - Planographic printing plate precursor and method for producing the same - Google Patents

Description

  The present invention relates to a lithographic printing plate precursor and a method for producing the same.

  The development of technology related to laser exposure and development in lithographic printing is remarkable. In particular, a solid-state laser / semiconductor laser having a light emitting region from the near infrared to the infrared can be easily obtained with a high output and a small size. A laser is very useful as an exposure light source when directly making a plate from digital data of a computer or the like, and the development of a lithographic printing plate corresponding to this is extremely important.

  The recording layer of the positive lithographic printing plate precursor for infrared laser contains, as essential components, an alkali-soluble binder resin and an IR dye that absorbs light and generates heat. The IR dye or the like functions as a development inhibitor that substantially lowers the solubility of the binder resin in the developer by interaction with the binder resin in the unexposed area (image area). On the other hand, in the exposed area (non-image area), the interaction between the IR dye and the binder resin is weakened by the generated heat and dissolves in an alkaline developer to form a lithographic printing plate.

  The basic performance required for the above-described lithographic printing plate precursor is developability that quickly realizes the formation of a clear image area, and conversely, chemical resistance that the recording layer is not dissolved in the unexposed area and is accurately maintained. And improvement in printing durability to increase the printable amount. However, these performances usually conflict with each other, and it is extremely difficult to raise all performance items at the same time. For example, in the printing plate precursor disclosed in the following Patent Documents 1 to 3, it is proposed that the recording layer contains a specific polymer. Usually, when a polymer having a large molecular weight is present in the recording layer, the printing durability and chemical resistance can be improved accordingly. However, the developability tends to be inferior, so that all performance cannot be improved in a balanced manner.

  By the way, a method of adding a surfactant to a developer is known as a method for imparting developability of a specific polymer having poor developability. In general, in the development processing of a positive lithographic printing plate precursor for infrared laser, the liquid activity needs to be kept constant in order to continuously and stably perform the processing. The liquid activity is controlled by alkali concentration (pH and conductivity). However, when a surfactant is added to the developer, the surfactant concentration cannot be kept constant if it is continuously used. There is a problem that the concentration gradually increases and the chemical resistance decreases, and conversely the surfactant concentration gradually decreases and the developability decreases.

JP 2007-017913 A Japanese Patent No. 4579639 Special table 2010-532488 gazette

  The inventor of the present application has conducted research and development for simultaneously increasing the performance of the above-mentioned characteristic items that are in conflict with each other in view of the technique of the above-mentioned patent document. That is, the present invention is a lithographic printing plate that achieves high printing durability and chemical resistance in lithographic printing, and also achieves good developability of the exposed area, suppression of running debris, and excellent concentration of waste liquid. The purpose is to provide the original edition.

As a result of intensive studies in view of the above problems, the present inventors have found the following findings. That is, in the recording layer of a positive lithographic printing plate precursor for infrared laser, a specific maleimide resin and an appropriate amount of a specific surfactant are allowed to coexist in the image recording layer, so that a predetermined amount of the specific surfactant is obtained. Is supplied to the development system. As a result, high printing durability in lithographic printing is achieved, and good developability of the exposed area is also achieved. Based on this finding, the present invention has been made.
The above problems have been achieved by the following means.
(1) An infrared-sensitive positive lithographic printing plate precursor having a recording layer in which a lower layer and an upper layer are arranged in this order on a support having a hydrophilic surface, wherein the upper layer and / or the lower layer are A lithographic printing plate precursor comprising the following maleimide resin A, an amphoteric surfactant and / or an anionic surfactant, and an infrared absorber in the same layer or in separate layers.
[Maleimide resin A:
Copolymer containing methacrylic acid, at least one selected from the group consisting of N-phenylmaleimide, N-cyclohexylmaleimide, and N-benzylmaleimide, and a monomer represented by the following general formula (a)]

（式中、Ｒ^１は水素原子またはメチル基である。Ｘは、炭素数２〜１２のアルキレン基、炭素数４〜８のオキシアルキレン基、又は−ＳｉＲａ_２−である。Ｒａはアルキル基であり、２つのアルキル基は互いに同じでも異なっていてもよい。ｍは１〜３の整数である。）

(Wherein R ¹ is a hydrogen atom or a methyl group. X is an alkylene group having 2 to 12 carbon atoms, an oxyalkylene group having 4 to 8 carbon atoms, or —SiRa ₂ —. Ra is an alkyl group. And the two alkyl groups may be the same or different from each other, and m is an integer of 1 to 3.)

(2) The lithographic printing plate precursor as described in (1), wherein the amphoteric surfactant is represented by any one of the following general formulas (I) to (III).

（一般式（I）〜（III）中、Ｒ^１１は炭素数６〜２４のアルキル基もしくは特定の連結基を介するアルキル基を表す。Ｒ^１２、Ｒ^１３はそれぞれ独立に炭素数１〜５のアルキル基を表す。Ｒ^１４、Ｒ^１５はそれぞれ独立に炭素数１〜５のアルキル基を表す。ただし、Ｒ^１４及びＲ^１５の少なくとも一方は末端に酸性基もしくはその塩を有する。Ｌ^１１は炭素数１〜４の連結基を表す。Ｘ⁻はカルボン酸イオン、スルホン酸イオン、硫酸イオン、ホスホン酸イオン、またはリン酸イオンを表す。）

(In General Formulas (I) to (III), R ¹¹ represents an alkyl group having 6 to 24 carbon atoms or an alkyl group via a specific linking group. R ¹² and R ¹³ each independently have 1 to 5 carbon atoms. R ¹⁴ and R ¹⁵ each independently represents an alkyl group having 1 to 5 carbon atoms, provided that at least one of R ¹⁴ and R ¹⁵ has an acidic group or a salt thereof at the terminal, and L ¹¹ represents carbon. .X which represents a linking group having 1 to 4 ^- represents a carboxylate ion, sulfonate ion, sulfate ion, phosphonate or phosphate ions).

(3) The lithographic printing plate precursor as described in (1), wherein the anionic surfactant is any one of the following general formulas (IV) to (VI ) :

（一般式（ＩＶ）〜（ＶＩ）中、Ｒ^１６ は炭素数６〜２４のアルキル基を表す。Ｌ^１２はフェニレン基又は単結合を表す。Ｄ^１１、Ｅ^１１、Ｆ^１１はスルホン酸イオンもしくはその塩、または硫酸イオンもしくはその塩を表す。Ｒ^１７は炭素数４〜１８のアルキル基を表す。Ｌ^１３はフェニレン基またはナフチレン基を表す。Ｒ^１８はフェニル基またはナフチル基を表す。Ｌ^１４はポリアルキレンオキシ基を表す。）

(In the general formula (IV) ~ (V I) , .D 11 R 1 6 is representative of the ^{.L 12} is a phenylene group or a single bond represents an alkyl group having 6 to 24 carbon ^atoms, E ^{11, F} 11 sulfonic acid Represents an ion or a salt thereof, or a sulfate ion or a salt thereof, R ¹⁷ represents an alkyl group having 4 to 18 carbon atoms, L ¹³ represents a phenylene group or a naphthylene group, and R ¹⁸ represents a phenyl group or a naphthyl group. L ¹⁴ represents a polyalkyleneoxy group .)

(4) The lithographic printing plate precursor as described in any one of (1) to (3), wherein m in the general formula (a) is 1 or 2.
(5) The lithographic printing plate precursor as described in any one of (1) to (4), wherein the surfactant is contained in an amount of 3 to 40 parts by mass with respect to 100 parts by mass of the maleimide resin A.
(6) The lithographic printing plate as described in any one of (1) to (5), wherein the layer on the support comprises, in order, an undercoat layer, a lower layer and an upper layer forming a recording layer. Original edition.
(7) The lithographic printing plate precursor as described in any one of (1) to (6), wherein the maleimide resin A is contained in a lower layer of a recording layer.
(8) The lithographic printing plate precursor as described in any one of (1) to (7), wherein the amphoteric surfactant is contained in the same layer as the maleimide resin A.
(9) An exposure step for image exposure of the recording layer of the lithographic printing plate precursor as described in any one of (1) to (8), a development step for development using an alkaline aqueous solution having a pH of 11.0 to 13.5, A method for producing a lithographic printing plate comprising
(10) The method for preparing a lithographic printing plate as described in (9), wherein the alkaline aqueous solution contains an anionic surfactant or an amphoteric surfactant.

  The lithographic printing plate precursor of the present invention realizes high printing durability and chemical resistance in lithographic printing, and at the same time, achieves good developability of the exposed area, suppression of running scum, and excellent concentration of phenomenon waste liquid. . Moreover, according to the production method of the present invention, a lithographic printing plate precursor exhibiting the above-described good performance can be produced.

FIG. 1 is a cross-sectional view schematically showing an embodiment in which the recording layer of the planographic printing plate precursor of the present invention has a multilayer structure.

Hereinafter, the present invention will be described in detail.
<Lithographic printing plate precursor>
The planographic printing plate precursor of the present invention comprises a recording layer provided by forming a lower layer and an upper layer in this order on the upper side of a support having a hydrophilic surface, and the upper layer and / or the lower layer comprises (a) It contains a specific maleimide resin A and (b) a specific surfactant. Components (a) and (b) may be added to the upper layer or the lower layer, and may be added to the same layer or in different layers. From the viewpoint of development latitude and the like, it is preferable to have a multilayer structure comprising a lower layer containing an infrared absorber and an upper layer for improving the solubility in an alkaline aqueous solution by heat (see Table A below for details). Note that the lower layer and the upper layer are arranged in this order on the upper side of the support, and if desired, other layers such as an undercoat layer and a surface protective layer may further be included. In the present invention, the lower layer and the upper layer are preferably formed adjacent to each other from the viewpoint of effects.

  By adopting the above configuration, the reason (action mechanism) for achieving the effects of simultaneously achieving printing durability, chemical resistance and developability in the present invention includes unexplained points. Presumed. In other words, amphoteric surfactants and anionic surfactants have higher hydration power and dispersion power than nonionic / cationic surfactants, and are added in a small amount in comparison with nonionic / cationic surfactants when added to the recording layer. It is estimated that a high effect is exhibited. For this reason, it is considered that a desired effect is exhibited without reducing the chemical resistance of the recording layer in combination with the action of the specific polymer. In addition, since the amphoteric surfactant has a positive charge such as an ammonium salt in the molecule, it is considered that the amphoteric surfactant also has an advantage that it hardly interacts with the material in the recording layer and hardly lowers the chemical resistance. . Hereinafter, preferred embodiments of the present invention will be described.

<Recording layer Lower layer>
(Maleimide resin A)

  The polymer material used for the lower layer includes methacrylic acid, a specific maleimide compound (at least one selected from the group consisting of N-phenylmaleimide, N-cyclohexylmaleimide, and N-benzylmaleimide), and a specific nitrogen-containing heterocyclic ring It is a copolymer containing a monomer (monomer represented by the following general formula (a)). The methacrylic acid is preferably about 5 mol% to about 40 mol%, more preferably about 10 mol% to about 30 mol% (in the present specification, when a to b are included, a and b are included) Meaning.) The specific maleimide compound is preferably about 20 mol% to about 75 mol%, more preferably about 35 mol% to about 60 mol%. If present at any option, it may preferably have from about 5 mol% to about 50 mol%, more preferably from about 15 mol% to about 40 mol% acrylamide, methacrylamide, or mixtures thereof. Good. Further, if present at any option, preferably has from about 10 mole% to about 70 mole%, more preferably from about 20 mole% to about 60 mole% acrylonitrile, methacrylonitrile, or mixtures thereof. May be. In addition, the specific nitrogen-containing heterocyclic monomer represented by the following general formula (a) may be contained in an amount of about 3 mol% to about 50 mol%, preferably about 10 mol% to about 40 mol%. It is.

In the formula, R ¹ is a hydrogen atom or a methyl group. X represents an alkylene group having 2 to 12 carbon atoms, an oxyalkylene group having 4-8 carbon atoms, or -SiRa ₂ - a. Ra is an alkyl group, and the two alkyl groups may be the same as or different from each other. m is an integer of 1-3. X is preferably —CH ₂ CH ₂ —, and m is preferably 1.

A preferred monomer for the preparation of the copolymer is N- [2- (2-oxo-1-imidazolidinyl) ethyl] methacrylamide, wherein R ¹ is CH ₃ , m is 1 and X is - _{(CH 2) n} -, a, n is 2. This monomer is represented by the following structure:

  Said compound can be manufactured by a conventional method. For example, N- [2- (2-oxo-1-imidazolidinyl) ethyl] methacrylamide can be prepared from aminoethylethyleneurea and methacrylic acid and is available from Aldrich (Milwaukee, Wisconsin, USA).

  In the present invention, the content of the specific maleimide resin A is not particularly limited, but is preferably 2 to 90% by mass with respect to the total solid content of the recording layer, and 50 to 50% with respect to the total solid content of the recording layer. More preferably, it is 90 mass%. When this amount is not less than the above lower limit value, suitable printing durability can be obtained. On the other hand, suitable developability can be acquired because it is below the said upper limit.

  In addition, in the description of group (atom group) in this specification, the description which does not describe substitution and unsubstituted includes the thing which has a substituent with the thing which does not have a substituent. For example, the “alkyl group” includes not only an alkyl group having no substituent (unsubstituted alkyl group) but also an alkyl group having a substituent (substituted alkyl group). In the present specification, the *** compound is used to mean a salt thereof, an ion thereof, and the like in addition to the compound itself. Typically, it means the compound and / or its salt. The same applies to the surfactant described below, and the compound defined therein may exist as an ion without a counter ion or may be a salt.

  Unless otherwise specified, the molecular weight and the degree of dispersion are values measured using a GPC (gel filtration chromatography) method, and the molecular weight is a weight average molecular weight in terms of polystyrene. The gel packed in the column used in the GPC method is preferably a gel having an aromatic compound as a repeating unit, and examples thereof include a gel made of a styrene-divinylbenzene copolymer. It is preferable to use 2 to 6 columns connected together. Examples of the solvent used include ether solvents such as tetrahydrofuran and amide solvents such as N-methylpyrrolidinone. The measurement is preferably performed at a solvent flow rate in the range of 0.1 to 2 mL / min, and most preferably in the range of 0.5 to 1.5 mL / min. By performing the measurement within this range, the apparatus is not loaded and the measurement can be performed more efficiently. The measurement temperature is preferably 10 to 50 ° C, most preferably 20 to 40 ° C. Note that the column and carrier to be used can be appropriately selected according to the physical properties of the polymer compound that is symmetrical to the measurement.

(Other resins)
The underlayer can also include one or more resins having active methylol and / or active alkylated mesylol groups. Such resins include, for example, resole resins and their alkylated analogs; methylol melamine resins and their alkylated analogs such as melamine-formaldehyde resins; methylol glycoluril resins and alkylated analogs such as glycoluril- Included are formaldehyde resins; thiourea-formaldehyde resins; guanamine-formaldehyde resins; and benzoguanamine-formaldehyde resins. Commercially available melamine-formaldehyde resins and glycoluril-formaldehyde resins include, for example, CYMEL® resin (Dyno Cyanamid) and NIKALAC® resin (Sanwa Chemical).

  The one or more resins having activated methylol and / or activated alkylated mesilol groups are preferably resole resins or a mixture of resole resins. Resole resins are well known to those skilled in the art. They are prepared by reaction of phenol with an aldehyde under basic conditions using excess phenol. Commercially available resole resins include, for example, GP649D99 resole (Georgia Pacific) and BKS-5928 resole resin (Union Carbide).

Further, the lower layer can include a first additional copolymer. The first additional copolymer is about 1 to about 30% by weight, preferably about 3 to about 20% by weight, more preferably about 5% by weight N-phenylmaleimide; about 1 to about 30% by weight, preferably about 5%. To about 20% by weight, more preferably about 10% by weight methacrylamide; about 20 to about 75% by weight, preferably about 35 to about 60% by weight acrylonitrile; and about 20 to about 75% by weight, preferably about 35 to about 60% by weight of the following structure:
CH ₂ = C (R ³ ) -CO ₂ -CH ₂ -CH ₂ -NH-CO-NH-pC ₆ H ₄ -R ²
One or more monomers of (wherein R ² is OH, COOH, or SO ₂ NH ₂ and R ³ is H or methyl);
Further optionally, if present, 1 to 30% by weight, preferably 3 to 20% by weight of the following structure:
CH ₂ = C (R ⁵ ) -CO-NH-pC ₆ H ₄ -R ⁴
(Wherein R ⁴ is OH, COOH, or SO ₂ NH ₂ and R ⁵ is H or methyl) is a copolymer comprising one or more monomers in polymerized form.

  In addition, the underlayer can also include a second additional copolymer. The second additional copolymer includes, in polymerized form, N-phenylmaleimide, methacrylamide, and methacrylic acid. These copolymers contain from about 25 to about 75 mole percent, preferably from about 35 to about 60 mole percent N-phenylmaleimide; from about 10 to about 50 mole percent, preferably from about 15 to about 40 mole percent methacrylamide. And from about 5 to about 30 mole percent, preferably from about 10 to about 30 mole percent methacrylic acid. These copolymers are disclosed in Shimazu US Pat. No. 6,294,311 and Savariar-Hauck US Pat. No. 6,528,228.

Well known to those skilled in the art, such as free radical polymerization, see eg: H. G. The polymeric materials and additional copolymers can be prepared by the methods described in Elias, “Macromolecules”, Volume 2, Second Edition (1984, Plenum, New York), Chapters 20 and 21. Useful radical initiators are peroxides such as benzoyl peroxide, hydroperoxides such as cumyl hydroperoxide, and azo compounds such as 2,2′-azobis (isobutyronitrile) (AIBN). . Suitable solvents include liquids that are inert to the reactants and do not particularly adversely affect the reaction. Typical solvents include, for example, esters such as ethyl acetate and butyl acetate; ketones such as methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, and acetone; alcohols such as methanol, ethanol, isopropyl alcohol, and butanol; Ethers such as dioxane and tetrahydrofuran; and mixtures thereof.

  In the present invention, the content of the other resin is not particularly limited, but is preferably 20 to 95% by mass with respect to the total solid content of the recording layer, and 50 to 90% by mass with respect to the total solid content of the recording layer. % Is more preferable.

<Surfactant>
-Amphoteric surfactants Preferred amphoteric surfactants include those represented by any one of the following general formulas (I) to (III).

R ¹¹ represents an alkyl group having 6 to 24 carbon atoms or an alkyl group via a specific linking group. Among these, a linear alkyl group having 8 to 18 carbon atoms, an alkyl group having 8 to 18 carbon atoms or via a specific linking group is preferable, and an amide group is preferable as the specific linking group.
R ¹² and R ¹³ each independently represents an alkyl group having 1 to 5 carbon atoms. Of these, a methyl group, an ethyl group, and a 2-hydroxyethyl group are preferable.
R ¹⁴ and R ¹⁵ each independently represents an alkyl group having 1 to 5 carbon atoms having an acidic group or a salt thereof (preferably a carboxylic acid or a salt thereof) at the terminal. Of these, a 2-carboxymethyl group, a 2-carboxyethyl group, a 2-carboxypropyl group, a carboxypolyethylene oxide group, and a carboxypolypropylene oxide group are preferable.
L ¹¹ represents a linking group having 1 to 4 carbon atoms. Of these, an alkylene group is preferable, and a methylene group, an ethylene group, and a propylene group are preferable.
X ⁻ represents a carboxylate ion or a salt thereof, a sulfonate ion or a salt thereof, a sulfate ion, a phosphonate ion or a salt thereof, or a phosphate ion or a salt thereof.
When the anion is a salt, examples of the counter ion include sodium ion, potassium ion, magnesium ion, and calcium ion.

  Specific examples of amphoteric surfactants include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, and N-tetradecyl-N, N-. Examples include betaine type.

Specific examples of the amphoteric surfactant represented by the general formula (I) include Levon 2000, Levon LD36 (manufactured by Sanyo Chemical Industries, Ltd.), Texnol R2 (Nihon Emulsifier Co., Ltd.) AM-301. AM-3130N (above, manufactured by Nikko Chemicals Co., Ltd.), Amphitole 20AB, Amphitole 20BS, Amphitole 24B, Amphitole 55AB, Amphitole 86B (above, manufactured by Kao Corp.), Adeka Anhhot AB-35L, Adeka Anhhot PB-30L (above , Manufactured by ADEKA Co., Ltd.), Anholex CB-1, Ampholex LB-2 (above, manufactured by Miyoshi Oil & Fats Co., Ltd.), Enagicol C-30B, Enagicol L-30B (above, manufactured by Lion Corp.), ovazoline BC, Obazoline CAB-30, Obazolin LB-SF, Obazolin LB ( Toho Chemical Industry Co., Ltd.), Softazolin CPB-R, Softazolin CPB, Softazolin LPB-R, Softazolin LPB, Softazolin MPB, Softazolin PKBP (Manufactured by Kawaken Fine Chemical Co., Ltd.), Nissan Annon BDC-S, Nissan Anon BDF-R, Nissan Anon BDF-SF, Nissan Anon BF, Nissan Anon BL-SF, Nissan Anon BL (manufactured by NOF Corporation) and the like can be mentioned.
Specific examples of the amphoteric surfactant represented by the general formula (II) include Amphithol 20N (manufactured by Kao Corporation), Softazoline LAO-C, Softazolin LAO (above, Kawaken Fine Chemical Co., Ltd.), Unisafe Examples include A-OM (manufactured by NOF Corporation), kachinal AOC (manufactured by Toho Chemical Industry Co., Ltd.), and Aromox DMC-W (manufactured by Lion Corporation).
Specific examples of the amphoteric surfactant represented by the above general formula (III) include Enagicol DP-30 (manufactured by Lion Co., Ltd.), Delifat 160C (manufactured by Cognis Japan Co., Ltd.), Pionin C158G (Takemoto Oil and Fat ( Etc.).

  Furthermore, specific examples of the amphoteric surfactant are exemplified below by chemical structural formulas.

  The compounds represented by the general formulas (I) to (III) can be used alone or in combination.

  Other examples of zwitterionic surfactants include amine oxides such as alkyldimethylamine oxide, betaines such as alkyl betaines, fatty acid amidopropyl betaines, alkyl imidazoles, and sodium alkylamino fatty acids. Amino acid systems such as

  In particular, alkyldimethylamine oxide which may have a substituent, alkylcarboxybetaine which may have a substituent, and alkylsulfobetaine which may have a substituent are preferably used. Specific examples thereof include compounds represented by formula (2) in paragraph No. [0256] of JP-A-2008-203359, formulas (I) and (II) in paragraph No. [0028] of JP-A-2008-276166. ), Compounds represented by formula (VI), and compounds described in paragraphs [0022] to [0029] of JP-A-2009-47927.

  As the zwitterionic surfactant used in the developer, a compound represented by the following general formula (A1), a compound represented by the general formula (A2), and a compound represented by the general formula (A3) are preferable.

In formulas (A1) to (A3), R ²¹ , R ³¹ and R ³⁵ each independently represent an alkyl group having 8 to 20 carbon atoms or a linking group having 8 to 20 carbon atoms in total. R ²² , R ²³ , R ³² and R ³³ each independently represents a group containing a hydrogen atom, an alkyl group or an ethylene oxide group. R ²⁴ and R ³⁴ each independently represents a single bond or an alkylene group. Two groups out of R ²¹ , R ²² , R ²³ and R ²⁴ may be bonded to each other to form a ring structure, and two groups out of R ³¹ , R ³² , R ³³ and R ³⁴ are They may combine to form a ring structure. L ³¹ and L ³² represent a linking group having 1 to 4 carbon atoms. Of these, an alkylene group is preferable, and a methylene group, an ethylene group, and a propylene group are preferable. X represents a hydrogen atom or an alkali metal (preferably sodium or potassium).

In the compound represented by the general formula (A1) or the compound represented by the general formula (A2) and the general formula (A3), the hydrophobic portion increases as the total carbon number increases, and the solubility in an aqueous developer is increased. Decreases. In this case, the solubility is improved by mixing an organic solvent such as alcohol to help dissolution into water as a dissolution aid, but if the total carbon number becomes too large, the surface activity is within the proper mixing range. The agent cannot be dissolved. Therefore, the total number of carbon atoms of R ^{21 to} R ²⁴ or R ^{31 to} R ³⁴ and R ³⁵ is preferably 10 to 40, more preferably 12 to 30.

The alkyl group having a linking group represented by R ²¹ or R ³¹ represents a structure having a linking group between the alkyl groups. That is, when there is one linking group, it can be represented by “-alkylene group-linking group-alkyl group”. Examples of the linking group include an ester bond, a carbonyl bond, and an amide bond. There may be two or more linking groups, but one is preferable, and an amide bond is particularly preferable. The total number of carbon atoms of the alkylene group bonded to the linking group is preferably 1 to 5. The alkylene group may be linear or branched, but is preferably a linear alkylene group. The alkyl group bonded to the linking group preferably has 3 to 19 carbon atoms, and may be linear or branched, but is preferably linear alkyl.

When R ²² or R ³² is an alkyl group, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. Either a straight chain or a branched chain may be used, but a straight chain alkyl group is preferable.

When R ²³ or R ³³ is an alkyl group, the carbon number is preferably 1 to 5, and particularly preferably 1 to 3. Either a straight chain or a branched chain may be used, but a straight chain alkyl group is preferable.
Examples of the group containing an ethylene oxide represented by R ²³ or ^{R _33,} can be a group represented by _{-Ra (CH 2 CH 2 O)} n Rb. Here, Ra represents a single bond, an oxygen atom or a divalent organic group (preferably having 10 or less carbon atoms), Rb represents a hydrogen atom or an organic group (preferably having 10 or less carbon atoms), and n is 1 to 10 Represents an integer.

When R ²⁴ and R ³⁴ are an alkylene group, the number of carbon atoms is preferably 1 to 5, and particularly preferably 1 to 3. Either a straight chain or a branched chain may be used, but a linear alkylene group is preferable.
The compounds represented by the general formulas (A1) to (A3) preferably have an amide bond, and more preferably have an amide bond as a linking group for R ²¹ or R ³¹ .
Representative examples of the compounds represented by the general formulas (A1) to (A3) are shown below, but the present invention is not limited thereto.

The compounds represented by the formulas (A1) to (A3) can be synthesized according to a known method. Moreover, it is also possible to use what is marketed. As a commercially available product, examples of the compound represented by the formula (A1) include SOFTAZOLIN LPB, SOFTAZOLIN LPB-R, Vista MAP, Takemoto Oil & Fats Takesurf C-157L manufactured by Kawaken Fine Chemicals. Examples of the compound represented by the formula (A2) include SOFTAZOLIN LAO manufactured by Kawaken Fine Chemical Co., Ltd., Amorgen AOL manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and the like.
Zwitterionic surfactants may be used alone or in combination of two or more in the developer.
For the amphoteric surfactant, reference can be made to JP-A-4-13149, JP-A-59-121044 and the like.

-Anionic surfactant As a preferable anionic surfactant, what is represented by either of the following general formula (IV)-(VI ) is mentioned.

（一般式（ＩＶ）〜（ＶＩ）中、Ｒ^１６ は炭素数６〜２４のアルキル基を表す。Ｌ^１２はフェニレン基又は単結合を表す。Ｄ^１１、Ｅ^１１、Ｆ^１１はスルホン酸イオンもしくはその塩、または硫酸イオンもしくはその塩を表す。Ｒ^１７は炭素数４〜１８のアルキル基を表す。Ｌ^１３はフェニレン基またはナフチレン基を表す。Ｒ^１８はフェニル基またはナフチル基を表す。Ｌ^１４はポリアルキレンオキシ基を表す。）

(In the general formula (IV) ~ (V I) , .D 11 R 1 6 is representative of the ^{.L 12} is a phenylene group or a single bond represents an alkyl group having 6 to 24 carbon ^atoms, E ^{11, F} 11 sulfonic acid Represents an ion or a salt thereof, or a sulfate ion or a salt thereof, R ¹⁷ represents an alkyl group having 4 to 18 carbon atoms, L ¹³ represents a phenylene group or a naphthylene group, and R ¹⁸ represents a phenyl group or a naphthyl group. L ¹⁴ represents a polyalkyleneoxy group .)

  Anionic surfactants include fatty acid salts, abietic acid salts, hydroxyalkane sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkyl benzene sulfonates, branched alkyl benzene sulfonates, alkyl naphthalene sulfonates. , Alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine sodium, N-alkyl sulfosuccinic acid monoamide disodium salts, petroleum sulfonates, sulfated castor oil , Sulfated beef tallow oil, fatty acid alkyl ester sulfates, alkyl sulfates, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates Tell salt, polyoxyethylene alkylphenyl ether sulfate ester salt, polyoxyethylene styryl phenyl ether sulfate ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene-anhydrous Partially saponified products of maleic acid copolymer, partially saponified products of olefin-maleic anhydride copolymer, naphthalene sulfonate formalin condensates, aromatic sulfonates, aromatic substituted polyoxyethylene sulfonates, etc. Is mentioned. Among these, dialkyl sulfosuccinates, alkyl sulfate esters and alkyl naphthalene sulfonates are particularly preferably used.

  As the anionic surfactant used in the treatment liquid of the present invention, an anionic surfactant containing a sulfonic acid or a sulfonate is particularly preferable. Anionic surfactants can be used alone or in combination.

  In the present invention, the content of the surfactant is not particularly limited, but is preferably more than 1% by mass and less than 20% by mass with respect to the total solid content of the layer containing the surfactant (in the example, the upper layer). More preferably, it is -15 mass%, and it is especially preferable that it is 5-10 mass%. By setting it as the said lower limit or more, generation | occurrence | production of running | fogging deficiency can be effectively suppressed especially and it is preferable. By setting it to the upper limit value or less, it is possible to sufficiently ensure film reduction and printing durability. In terms of the relationship with the specific maleimide resin, from the same viewpoint, it is preferably 3 to 20 parts by mass with respect to 100 parts by mass. By setting it as the said lower limit or more, generation | occurrence | production of running | fogging deficiency can be effectively suppressed especially and it is preferable.

Other surfactants The specific developer may contain nonionic surfactants, cationic surfactants and the like other than those described above as long as the effects of the present invention are not impaired.

Nonionic surfactants include polyethylene glycol type higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, polyethylene glycol adducts of aromatic compounds, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, Higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. And polyhydric alcohol glycerol fatty acid ester, pentaerythritol fatty acid ester, Rubitoru and fatty acid esters of sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.
The nonionic surfactant preferably includes a nonionic aromatic ether surfactant, and is an adduct of benzene or naphthalene that may have a non-dissociable substituent, or ethylene oxide and / or propylene oxide of naphthalene. It is more preferable. This surfactant may be used individually by 1 type, or may be used in combination of 2 or more type.

  Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

Even when a nonionic surfactant or a cationic agent is used in combination, the content of the amphoteric surfactant or anionic surfactant is preferably the highest, and the total amount of the amphoteric surfactant or anionic surfactant is the total amount of the surfactant. It is preferable that it is 50 mass% or more, and it is more preferable that it is 60 mass% or more.
For the amphoteric surfactant, reference can be made to JP-A-4-13149, JP-A-59-121044 and the like.

  The content of these other surfactants is preferably 0.01 to 10% by mass and more preferably 0.01 to 5% by mass with respect to the total solid content of the recording layer.

<Infrared absorber>
The lithographic printing plate precursor according to the invention contains an infrared absorber in its recording layer. The infrared absorber is not particularly limited as long as it is a dye that absorbs infrared light and generates heat, and various dyes known as infrared absorbers can be used.
As the infrared absorber that can be used in the present invention, commercially available dyes and known ones described in literature (for example, “Dye Handbook” edited by Organic Synthetic Chemistry Association, published in 1970) can be used. Specific examples include azo dyes, metal complex azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, and cyanine dyes. In the present invention, among these dyes, those that absorb at least infrared light or near-infrared light are preferable because they are suitable for use in lasers that emit infrared light or near-infrared light, and cyanine dyes are particularly preferred. preferable.

  Particularly preferred among these dyes are cyanine dyes, phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts, thiopyrylium dyes, and nickel thiolate complexes. Furthermore, the cyanine dye represented by the following general formula (a) is most preferable because it gives high polymerization activity and is excellent in stability and economy when used in the upper layer in the present invention.

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , X ² -L ¹ or a group shown below. X ² represents an oxygen atom or a sulfur atom. L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, an aromatic ring having a hetero atom, or a hydrocarbon group having 1 to 12 carbon atoms including a hetero atom. In addition, a hetero atom here shows N, S, O, a halogen atom, and Se.

In the above formula, Xa ^- has Za described later ^- has the same definition as, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the storage stability of the photosensitive layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms, and R ¹ and R ² are bonded to each other to form a 5-membered ring or It is particularly preferable that a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned.
Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxyl groups, and sulfo groups.
R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in the structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion from the storage stability of the photosensitive layer coating solution, and particularly preferably a perchlorate ion, a hexagonal ion. Fluorophosphate ion and aryl sulfonate ion.

Specific examples of the cyanine dye represented by the general formula (a) that can be suitably used include paragraph numbers [0017] to [0019] of JP-A No. 2001-133969 and paragraph numbers of JP-A No. 2002-40638. [0012] to [0038] and paragraphs [0012] to [0023] described in JP-A No. 2002-23360.
The cyanine dye A shown below is particularly preferable as the infrared absorber.

赤外線吸収剤を添加する際の添加量としては、全固形分に対し、０．０１〜５０質量％であることが好ましく、０．１〜３０質量％であることがより好ましく、１．０〜３０質量％であることが特に好ましい。添加量が０．０１質量％以上であると、高感度となり、また、５０質量％以下であると、層の均一性が良好であり、層の耐久性に優れる。

As an addition amount at the time of adding an infrared absorber, it is preferable that it is 0.01-50 mass% with respect to the total solid, It is more preferable that it is 0.1-30 mass%, 1.0- It is especially preferable that it is 30 mass%. When the addition amount is 0.01% by mass or more, high sensitivity is obtained, and when it is 50% by mass or less, the uniformity of the layer is good and the durability of the layer is excellent.

(Other alkali-soluble resins)
In the present invention, the term “alkali-soluble” means that it is soluble in an alkaline aqueous solution having a pH of 11.0 to 13.5 (preferably 12.0 to 13.5, more preferably 12.5 to 13.5) by processing for a standard development time.
The other alkali-soluble resin used in the lower layer is not particularly limited as long as it has a property of being dissolved when contacted with an alkaline developer, but the main chain and / or side chain in the polymer has a phenolic hydroxyl group, A resin having an acidic functional group such as a sulfonic acid group, a phosphoric acid group, a sulfonamide group, or an active imide group is preferable. Such a resin containing 10 mol% or more of a monomer having an acidic functional group imparting alkali solubility. A resin containing 20 mol% or more is more preferable. When the copolymerization component of the monomer that imparts alkali solubility is 10 mol% or more, sufficient alkali solubility is obtained and the developability is excellent.
Furthermore, as described in U.S. Pat. No. 4,123,279, a phenol having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin; Examples thereof include condensation polymers with formaldehyde. Moreover, it is preferable that the mass mean molecular weight (Mw) is 500 or more, and it is more preferable that it is 1,000-700,000. Moreover, it is preferable that the number average molecular weight (Mn) is 500 or more, and it is more preferable that it is 750-650,000. The dispersity (mass average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The other alkali-soluble resin preferably has a mass average molecular weight of 2,000 or more and a number average molecular weight of 500 or more, a mass average molecular weight of 5,000 to 300,000, and a number average molecular weight of 800 to 250. Is more preferable. The dispersity (mass average molecular weight / number average molecular weight) of the other alkali-soluble resin is preferably 1.1 to 10.
Other alkali-soluble resins optionally contained in the lower layer may be used alone or in combination of two or more.
The content of the other alkali-soluble resin with respect to the total solid content of the lower layer in the present invention may be used in an addition amount of 0 to 98% by mass. Moreover, it can contain in the ratio of 80 mass parts or less with respect to 100 mass parts of said (A) star-shaped polymers.

<Upper layer>
There is no particular limitation on the mechanism for improving the solubility in an aqueous alkali solution by heat in the upper layer, and any mechanism can be used as long as it includes a binder resin and improves the solubility of the heated region. As heat utilized for image formation, heat generated when a lower layer containing an infrared absorber is exposed can be used. The upper layer whose solubility in an alkaline aqueous solution is improved by heat includes, for example, a layer containing an alkali-soluble resin having a hydrogen bonding ability such as novolak and urethane, a water-insoluble and alkali-soluble resin, and a compound having a dissolution-inhibiting action. A layer, a layer containing an ablatable compound, and the like. Further, by adding an infrared absorber to the upper layer, the heat generated in the upper layer can also be used for image formation. As the structure of the upper layer containing the infrared absorber, for example, a layer containing an infrared absorber, a water-insoluble and alkali-soluble resin and a compound having a dissolution-inhibiting action, an infrared absorber, a water-insoluble and alkali-soluble resin, and an acid by heat Examples thereof include a layer containing a generated compound.

(Water-insoluble and alkali-soluble resin)
The upper layer according to the present invention preferably contains a water-insoluble and alkali-soluble resin. By containing the alkali-soluble resin, an interaction is formed between the infrared absorber and the polar group of the alkali-soluble resin, and a positive-type photosensitive layer is formed. Including those mentioned above, for example, polyamide resin, epoxy resin, polyacetal resin, acrylic resin, methacrylic resin, polystyrene resin, novolac type phenol resin and the like can be preferably exemplified.
The alkali-soluble resin that can be used in the present invention is not particularly limited as long as it has a property of dissolving when contacted with an alkaline developer, but contains an acidic group in the main chain and / or side chain in the polymer. It is preferable that the polymer is a homopolymer, a copolymer thereof, or a mixture thereof.
The alkali-soluble resin having such an acidic group preferably has a functional group such as a phenolic hydroxyl group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a sulfonamide group, or an active imide group. Therefore, such a resin can be suitably produced by copolymerizing a monomer mixture containing one or more ethylenically unsaturated monomers having the functional group. Preferred examples of the ethylenically unsaturated monomer having a functional group include, in addition to acrylic acid and methacrylic acid, a compound represented by the following formula and a mixture thereof. In the following formula, R represents a hydrogen atom or a methyl group.

  The alkali-soluble resin that can be used in the present invention is preferably a polymer compound obtained by copolymerizing another polymerizable monomer in addition to the polymerizable monomer. The copolymerization ratio in this case is 10 mol of a monomer that imparts alkali solubility such as a monomer having a functional group such as a phenolic hydroxyl group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a sulfonamide group, or an active imide group. %, Preferably 20 mol% or more. When the copolymerization component of the monomer that imparts alkali solubility is 10 mol% or more, sufficient alkali solubility is obtained and the developability is excellent.

Examples of other polymerizable monomers that can be used include the compounds listed below.
Alkyl acrylates and alkyl methacrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. Acrylamide or methacrylamide such as acrylamide, methacrylamide, N-methylacrylamide, N-ethylacrylamide, N-phenylacrylamide, etc. Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate. Styrenes such as styrene, α-methylstyrene, methylstyrene, and chloromethylstyrene. Other nitrogen atom-containing monomers such as N-vinylpyrrolidone, N-vinylpyridine, acrylonitrile and methacrylonitrile. N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-butylmaleimide, N-phenylmaleimide, N-2-methylphenylmaleimide, N-2,6-diethylphenylmaleimide, N-2-chlorophenylmaleimide, Maleimides such as N-cyclohexylmaleimide, N-laurylmaleimide, N-hydroxyphenylmaleimide and the like.
Among these other ethylenically unsaturated monomers, (meth) acrylic acid esters, (meth) acrylamides, maleimides, and (meth) acrylonitrile are preferably used.

  Moreover, as an alkali-soluble resin, a novolak resin is mentioned preferably as mentioned above.

The water-insoluble and alkali-soluble resin preferably has a mass average molecular weight of 2,000 or more and a number average molecular weight of 500 or more, a mass average molecular weight of 5,000 to 300,000, and a number average molecular weight of 800 to More preferably, it is 250,000. Further, the dispersity (mass average molecular weight / number average molecular weight) of the alkali-soluble resin is preferably 1.1 to 10.
The alkali-soluble resin in the upper layer of the image recording material of the present invention may be used alone or in combination of two or more.
In the present invention, the content of the alkali-soluble resin relative to the total solid content of the upper layer is preferably 2.0 to 99.5% by mass in the total solid content, and preferably 10.0 to 99.0% by mass. Is more preferable, and it is still more preferable that it is 20.0-90.0 mass%. When the addition amount of the alkali-soluble resin is 2.0% by mass or more, the recording layer (photosensitive layer) is excellent in durability, and when it is 99.5% by mass or less, both sensitivity and durability are excellent. .

(Acid generator)
The upper layer of the image recording layer preferably contains an acid generator from the viewpoint of improving sensitivity.
In this invention, an acid generator is a compound which generate | occur | produces an acid with light or a heat | fever, and points out the compound which decomposes | disassembles and generate | occur | produces an acid by infrared irradiation or a heating of 100 degreeC or more. The acid generated is preferably a strong acid having a pKa of 2 or less, such as sulfonic acid and hydrochloric acid. The acid generated from the acid generator functions as a catalyst, the chemical bond in the acid-decomposable group is cleaved to become an acid group, and the solubility in the upper alkaline aqueous solution is further improved.

Examples of the acid generator suitably used in the present invention include onium salts such as iodonium salts, sulfonium salts, phosphonium salts, and diazonium salts. Specific examples include compounds described in US Pat. No. 4,708,925 and JP-A-7-20629. In particular, iodonium salts, sulfonium salts, and diazonium salts having a sulfonate ion as a counter ion are preferable. Examples of the diazonium salt include diazonium compounds described in U.S. Pat. No. 3,867,147, diazonium compounds described in U.S. Pat. No. 2,632,703, and JP-A-1-102456 and JP-A-1-102457. The diazo resin described in the publication is also preferable. Also preferred are benzyl sulfonates described in US Pat. No. 5,135,838 and US Pat. No. 5,200,544. Furthermore, active sulfonic acid esters and disulfonyl compounds described in JP-A-2-100054, JP-A-2-100055 and Japanese Patent Application No. 8-9444 are also preferable. In addition, haloalkyl-substituted S-triazines described in JP-A-7-271029 are also preferable.
Further, the compound described as “acid precursor” in JP-A-8-220552 or “(a) a compound capable of generating an acid upon irradiation with active light” in JP-A-9-171254 And the like can be applied as the acid generator of the present invention.

Among these, from the viewpoint of sensitivity and stability, it is preferable to use an onium salt compound as the acid generator. Hereinafter, the onium salt compound will be described.
Examples of the onium salt compound that can be suitably used in the present invention include compounds known as compounds that generate an acid by being decomposed by thermal energy generated from an infrared absorber upon exposure to infrared light. Examples of the onium salt compound suitable for the present invention include known thermal polymerization initiators and compounds having an onium salt structure described below having a bond with small bond dissociation energy from the viewpoint of sensitivity.
Examples of the onium salt suitably used in the present invention include known diazonium salts, iodonium salts, sulfonium salts, ammonium salts, pyridinium salts, azinium salts, and the like. Among them, triarylsulfonium or diaryliodonium sulfonic acid Salts, carboxylates, BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ^{— and the} like are preferable.
Specific examples of the azinium salt compound include compounds described in paragraph numbers [0047] to [0056] of JP-A-2008-195018. The N—O bond described in JP-A-63-138345, JP-A-63-142345, JP-A-63-142346, JP-A-63-143537, and JP-B-46-42363 is also disclosed. A group of compounds having the above is also suitably used as the acid generator in the present invention.
When the acid generator is added to the upper layer, the preferable addition amount is 0.01 to 50% by mass, preferably 0.1 to 40% by mass, more preferably 0.5 to 30% by mass with respect to the total solid content of the upper layer. % Range. When the addition amount is in the above range, an improvement in sensitivity, which is an effect of addition of an acid generator, is observed, and generation of a residual film in a non-image area is suppressed.

(Acid growth agent)
An acid proliferating agent may be added to the upper layer in the present invention.
The acid proliferating agent in the present invention is a compound substituted with a relatively strong acid residue, and is a compound that is easily eliminated in the presence of an acid catalyst to newly generate an acid. That is, it decomposes by an acid catalytic reaction and generates an acid again (hereinafter referred to as ZOH in the general formula). One or more acids are increased in one reaction, and the sensitivity is dramatically improved by increasing the acid concentration at an accelerated rate as the reaction proceeds. The strength of the generated acid is 3 or less as an acid dissociation constant (pKa), and preferably 2 or less. If the acid is weaker than this, an acid-catalyzed elimination reaction cannot be caused.
Examples of the acid used for such an acid catalyst include dichloroacetic acid, trichloroacetic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, and phenylsulfonic acid.

  Examples of the acid proliferating agent include WO95 / 29968, WO98 / 24000, JP-A-8-305262, JP-A-9-34106, JP-A-8-248561, JP-A-8-503082, and US Pat. No. 5,445. No. 9,917, JP-A-8-503081, US Pat. No. 5,534,393, US Pat. No. 5,395,736, US Pat. No. 5,741,630, US Pat. No. 5,334,489 , U.S. Patent No. 5,582,956, U.S. Patent No. 5,578,424, U.S. Patent No. 5,453,345, U.S. Patent No. 5,445,917, European Patent No. 665,960, EP 757,628, EP 665,961, U.S. Pat. No. 5,667,943, JP-A-10-1598, etc. It is possible to have.

  As an addition amount in the case of adding an acid proliferation agent in an upper layer, it is 0.01-20 mass% in conversion of solid content, Preferably it is 0.01-10 mass%, More preferably, it is 0.1-5 mass%. It is a range. When the amount of the acid proliferating agent is within the above range, the effect of adding the acid proliferating agent is sufficiently obtained, the sensitivity is improved, the decrease in the film strength of the image area is suppressed, and the excellent film resulting from the specific polyurethane Strength is maintained.

(Other additives)
In forming the lower layer and the upper layer, in addition to the above essential components, various additives can be further added as necessary as long as the effects of the present invention are not impaired. The additives listed below may be added only to the lower layer, may be added only to the upper layer, or may be added to both layers.

(Development accelerator)
For the purpose of improving sensitivity, acid anhydrides, phenols, and organic acids may be added to the upper layer and / or the lower layer.
As the acid anhydrides, cyclic acid anhydrides are preferable. Specific examples of the cyclic acid anhydrides include phthalic anhydride, tetrahydrophthalic anhydride, and hexahydro anhydride described in US Pat. No. 4,115,128. Phthalic acid, 3,6-endooxytetrahydrophthalic anhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleic anhydride, α-phenylmaleic anhydride, succinic anhydride, pyromellitic anhydride and the like can be used. Examples of acyclic acid anhydrides include acetic anhydride.
Examples of phenols include bisphenol A, 2,2′-bishydroxysulfone, p-nitrophenol, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4- Examples include hydroxybenzophenone, 4,4 ′, 4 ″ -trihydroxytriphenylmethane, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane. .
Examples of the organic acids are described in JP-A-60-88942, JP-A-2-96755, and the like. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, Ethyl sulfuric acid, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4-cyclohexene Examples include -1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like.
The proportion of the acid anhydride, phenols and organic acids in the total solid content of the lower or upper layer is preferably 0.05 to 20% by mass, more preferably 0.1 to 15% by mass, and 0.1 to 10%. Mass% is particularly preferred.

(Other surfactants)
In addition to the above, the upper layer and / or the lower layer improve the coatability and expand the stability of the processing with respect to the development conditions, in addition to JP-A-62-170950, JP-A-11-288093, A fluorine-containing monomer copolymer as described in JP-A-2003-57820 can be added.
The ratio of the other surfactant to the total solid content of the layer containing the surfactant is preferably 0.01 to 15% by mass, more preferably 0.01 to 5% by mass, and 0.05 to 2.%. 0% by mass is more preferable.

(Bake-out agent / colorant)
In the upper layer and / or the lower layer, 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.
Examples of the printing-out agent and the colorant are described in detail in paragraph numbers [0122] to [0123] of JP-A-2009-229917, and the compounds described therein can be applied to the present invention.
These dyes are preferably added at a rate of 0.01 to 10% by mass, more preferably at a rate of 0.1 to 3% by mass, based on the total solid content of the lower layer or upper layer.

(Plasticizer)
A plasticizer may be added to the upper layer and / or the lower layer in order to impart flexibility or the like 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.
These plasticizers are preferably added at a rate of 0.5 to 10% by mass, more preferably at a rate of 1.0 to 5% by mass, based on the total solid content of the lower layer or upper layer.

(Wax agent)
In the upper layer, a compound that lowers the static friction coefficient of the surface can be added for the purpose of imparting resistance to scratches. Specifically, as described in US Pat. No. 6,117,913, JP-A No. 2003-149799, JP-A No. 2003-302750, or JP-A No. 2004-12770, A compound having an ester of a long-chain alkyl carboxylic acid can be exemplified.
The amount to be added is preferably 0.1 to 10% by mass and more preferably 0.5 to 5% by mass in the upper layer.

<Formation of lower layer and upper layer>
The upper layer and the lower layer in the lithographic printing plate precursor according to the invention can be usually formed by dissolving the above components in a solvent and coating the solution on a suitable support.
Solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxy Examples include ethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, and toluene. It is not limited to. These solvents are used alone or in combination.

In principle, the lower layer and the upper layer are preferably formed by separating two layers.
As a method for forming the two layers separately, for example, a method using a difference in solvent solubility between the component contained in the lower layer and the component contained in the upper layer can be mentioned.
In addition, as another method for separating and forming the two layers, there is a method of rapidly drying and removing the solvent after applying the upper layer. By using this method in combination, the separation between layers is further improved. Will be done.
Hereinafter, although these methods are explained in full detail, the method of isolate | separating and apply | coating two layers is not limited to these.

  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 solvent system in which any of the components contained in the lower layer is insoluble is used when the upper layer coating solution is applied. Is. 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. -It is possible to form two layers by drying and then dissolving the upper layer mainly composed of alkali-soluble resin with methyl ethyl ketone, 1-methoxy-2-propanol, etc., and applying and drying.

  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 traveling direction, or heating such as steam is performed. 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.

The coating amount after drying of the lower layer component coated on the support of the lithographic printing plate precursor according to the present invention is preferably in the range of 0.5 to 4.0 g / m ² , 0.6 to 2.5 g. / M ² is more preferable. When it is 0.5 g / m ² or more, printing durability is excellent, and when it is 4.0 g / m ² or less, image reproducibility and sensitivity are excellent.
Moreover, it is preferable that it is the range of 0.05-1.0 g / m < ² >, and, as for the application quantity after drying of an upper layer component, it is more preferable that it is the range of 0.08-0.7 g / m < ² >. If it is 0.05 g / ^{m 2} or more, development latitude, and excellent scratch resistance, if it is 1.0 g / ^{m 2} or less, excellent sensitivity.
The lower layer and the coating amount after drying of the combined upper layer, preferably in the range of 0.6~4.0g / ^{m 2,} more preferably in the range of 0.7 to 2.5 g / ^{m 2} . When it is 0.6 g / m ² or more, printing durability is excellent, and when it is 4.0 g / m ² or less, image reproducibility and sensitivity are excellent.

<Configuration of recording layer>
Hereinafter, although the case where the recording layer has a multilayer structure will be described, examples of the layer configuration and the arrangement of each component in the preferred embodiment of the present invention include the following combinations.

  The lower layer preferably contains the infrared absorber. Furthermore, as long as the effects of the present invention are not impaired, other components may be contained as desired. For example, an alkali-soluble resin (referred to as another alkali-soluble resin) having a structure different from that of the resin can be used.

<Support>
As the support used in the lithographic printing plate precursor according to the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate having particularly good dimensional stability and relatively low cost 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 preferably 10% by mass or less.
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 preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and particularly preferably 0.2 to 0.3 mm. preferable.

Such an aluminum plate may be subjected to a surface treatment such as a roughening treatment or an anodizing treatment as necessary. As for the surface treatment of the aluminum support, for example, a degreasing treatment with a surfactant, an organic solvent, an alkaline aqueous solution, or the like, as described in detail in [0167] to [0169] of JP2009-175195A, surface The surface roughening treatment, anodizing treatment, and the like are appropriately performed.
The anodized aluminum surface is subjected to a hydrophilic treatment as necessary.
Examples of the hydrophilization treatment include an alkali metal silicate (for example, sodium silicate aqueous solution) method, a method of treating with potassium zirconate fluoride or polyvinylphosphonic acid as disclosed in [0169] of 2009-175195. Used.

<Undercoat layer>
In the present invention, an undercoat layer can be provided between the support and the lower layer as necessary.
As an undercoat layer component, various organic compounds are used. For example, phosphonic acids having amino groups such as carboxymethylcellulose and dextrin, organic phosphonic acids, organic phosphoric acids, organic phosphinic acids, amino acids, and hydroxy groups. Preferred examples thereof include hydrochlorides of amines and the like. These undercoat layer components may be used singly or in combination of two or more. Details of the compounds used for the undercoat layer and the method for forming the undercoat layer are described in paragraphs [0171] to [0172] of JP2009-175195A, and these descriptions are also applied to the present invention. The
The coverage of the organic undercoat layer is preferably 2 to 200 mg / ^{m 2,} and more preferably 5 to 100 mg / ^{m 2.} When the coating amount is in the above range, sufficient printing durability can be obtained.

<Back coat layer>
A back coat layer is provided on the back surface of the support of the lithographic printing plate precursor according to the invention, if necessary. Such a back coat layer comprises a metal oxide obtained by hydrolysis and polycondensation of an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174. A coating layer is preferably used. Among these coating layers, silicon alkoxy compounds such as Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (OC ₃ H ₇ ) ₄ , Si (OC ₄ H ₉ ) ₄ are available at a low price. The coating layer of the metal oxide obtained therefrom is particularly preferable because of its excellent developer resistance.
The lithographic printing plate precursor produced as described above is imagewise exposed and then developed.

<Plate making method of lithographic printing plate>
The lithographic printing plate production method of the present invention comprises an exposure step of exposing the infrared sensitive positive lithographic printing plate precursor of the present invention imagewise with infrared rays, and a pH of 11.0 to 13.5 (preferably 12.0 to 13.5, more preferably 12.5 to 13.5), and a development step of developing using an alkaline aqueous solution in this order.
According to the method for producing a lithographic printing plate of the present invention, the shrinkage is improved, and the obtained lithographic printing plate is free from the occurrence of stains due to the residual film in the non-image area, and the strength and durability of the image area. Excellent.
Hereafter, each process of the plate making method of this invention is demonstrated in detail.

<Exposure process>
The plate making method of the lithographic printing plate of the present invention includes an exposure step of exposing the infrared sensitive positive lithographic printing plate precursor of the present invention imagewise.
The actinic ray light source used for image exposure of the lithographic printing plate precursor according to the invention is preferably a light source having an emission wavelength in the near infrared to infrared region, and more preferably a solid laser or a semiconductor laser. Among them, in the present invention, it is particularly preferable that the image exposure is performed by a solid laser or a semiconductor laser that emits infrared rays having a wavelength of 750 to 1,400 nm.
The laser output 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.
The energy applied to the planographic printing plate precursor is preferably 10 to 300 mJ / cm ² . When it is in the above range, curing can proceed sufficiently, laser ablation can be suppressed, and damage to the image can be prevented.

  The exposure in the present invention can be performed by overlapping the light beams of the light sources. Overlap means that the sub-scanning pitch width is smaller than the beam diameter. The overlap can be expressed quantitatively by FWHM / sub-scanning pitch width (overlap coefficient), for example, when the beam diameter is expressed by the full width at half maximum (FWHM) of the beam intensity. In the present invention, the overlap coefficient is preferably 0.1 or more.

  The scanning method of the light source of the exposure apparatus that can be used in the present invention is not particularly limited, and a cylindrical outer surface scanning method, a cylindrical inner surface scanning method, a planar scanning method, and the like can be used. The channel of the light source may be a single channel or a multi-channel, but in the case of a cylindrical outer surface system, a multi-channel is preferably used.

<Development process>
-Developer The lithographic printing plate making method of the present invention includes a developing step of developing using an aqueous alkaline solution. The alkaline aqueous solution (hereinafter also referred to as “developer”) used in the development step has a pH of 11.0 to 13.5 (preferably 12.0 to 13.5, more preferably 12.5 to 13.5). This is an alkaline aqueous solution. In addition, pH here is defined by the value measured by F-51 (brand name) by HORIBA in room temperature (20 degreeC).

In the present invention, even when a developer having a high pH is used, since the specific surfactant is combined with a specific polymer compound and applied to the photosensitive layer, high stability processability can be realized.
More specifically, the automatic processor (automatic machine) controls the alkali concentration by the electric conductivity, but if the alkali concentration is kept constant, the surfactant concentration essential for developing the polyurethane binder gradually increases. It will increase / decrease. That is, the stability of the development process is lacking.
On the other hand, in the present invention, a surfactant is charged in the image recording layer of the lithographic printing plate precursor in advance, and the surfactant concentration is kept constant from the beginning even if the developer is managed only with an alkali concentration. Has the advantage of being

  Examples of the alkaline component of the developer include lithium, sodium, and potassium, and sodium is particularly preferable. These carbonates can be used. These may be used alone or in combination of two or more.

  The developer preferably contains a surfactant, and more preferably contains at least an anionic surfactant or an amphoteric surfactant. Surfactant contributes to the improvement of processability. The surfactant is preferably the same as the surfactant contained in the image recording layer of the lithographic printing plate precursor. With such a combination, the surfactant in the image recording layer and the surfactant in the developer interact with each other, contributing to the realization of better developability and stability.

As the surfactant used in the developer, any of anionic, nonionic, cationic and amphoteric surfactants can be used. As described above, anionic and amphoteric (betaine) These surfactants are preferred.
The anionic surfactant used in the developer of the present invention is not particularly limited, but fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts, dialkylsulfosuccinic acid salts, linear alkylbenzenesulfonic acid salts. Branched alkylbenzene sulfonates, alkyl naphthalene sulfonates, alkyl diphenyl ether (di) sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, N-methyl-N-oleyl taurine Sodium, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, sulfate esters of fatty acid alkyl esters, alkyl sulfates Ester salts, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styrylphenyl ether sulfates, alkyl phosphate esters, polyoxyethylene alkyl ether phosphates Salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene-maleic anhydride copolymer partial saponification products, olefin-maleic anhydride copolymer partial saponification products, naphthalene sulfonate formalin condensates, etc. Can be mentioned. Among these, alkylbenzene sulfonates, alkyl naphthalene sulfonates, and alkyl diphenyl ether (di) sulfonates are particularly preferably used.

The nonionic surfactant used in the developer of the present invention is not particularly limited, but is a polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide adduct, phenol ethylene oxide adduct. , Naphthol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide addition Dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) Id) block copolymer, fatty acid ester of polyhydric alcohol type glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol, fatty acid amide of alkanolamines, etc. Is mentioned. Among these, those having an aromatic ring and an ethylene oxide chain are preferable, and an alkyl-substituted or unsubstituted phenol ethylene oxide adduct or an alkyl-substituted or unsubstituted naphthol ethylene oxide adduct is more preferable.
The amphoteric surfactant used in the developer of the present invention is not particularly limited, but is alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium. Examples include betaine and N-tetradecyl-N, N-betaine type.

As the surfactant used in the developer, an anionic surfactant and an amphoteric surfactant are preferable, and an anionic surfactant containing a sulfonic acid or a sulfonate is particularly preferable.
Surfactants can be used alone or in combination.
The content of the surfactant in the developer is preferably from 0.01 to 10% by mass, and more preferably from 0.01 to 5% by mass.

-Development processing Although there will be no restriction | limiting in particular if the temperature of image development is developable, It is preferable that it is 60 degrees C or less, and it is more preferable that it is 15-40 degreeC. In the development processing using an automatic developing machine, the developing solution may be fatigued depending on the processing amount. Therefore, the processing capability may be restored using a replenishing solution or a fresh developing solution. An example of development and post-development processing is a method in which alkali development is performed, alkali is removed in a post-water washing step, gumming is performed in a gumming step, and drying is performed in a drying step. As another example, a method in which pre-water washing, development and gumming are simultaneously performed by using an aqueous solution containing carbonate ions, hydrogen carbonate ions and a surfactant can be preferably exemplified. Therefore, the pre-water washing step is not particularly required, and it is preferable to perform the drying step after performing pre-water washing, development and gumming in one bath only by using one liquid. After development, it is preferable to dry after removing excess developer using a squeeze roller or the like.

  The development process can be preferably carried out by an automatic processor equipped with a rubbing member. As an automatic processor, for example, an automatic processor described in JP-A-2-220061 and JP-A-60-59351, which performs a rubbing process while conveying a lithographic printing plate precursor after image exposure, or a cylinder Examples thereof include an automatic processor described in US Pat. Nos. 5,148,746, 5,568,768 and British Patent 2,297,719, which rub the lithographic printing plate precursor after image exposure set above while rotating a cylinder. Among these, an automatic processor using a rotating brush roll as the rubbing member is particularly preferable.

It is preferable to provide a drying step continuously or discontinuously after the development step. Drying is performed by hot air, infrared rays, far infrared rays, or the like.
As an automatic processor suitably used in the method for preparing a lithographic printing plate according to the present invention, an apparatus having a developing unit and a drying unit is used, and development and gumming are performed on a lithographic printing plate precursor in a developing tank. And then dried in a drying section to obtain a lithographic printing plate.

Further, for the purpose of improving printing durability, the developed printing plate can be heated under very strong conditions. The heating temperature is usually in the range of 200 to 500 ° C. If the temperature is low, sufficient image strengthening action cannot be obtained, and if it is too high, problems such as deterioration of the support and thermal decomposition of the image area may occur.
The lithographic printing plate obtained in this way is applied to an offset printing machine and is suitably used for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in more detail, this invention is not limited to them.

(Example 1, Comparative Example 1)
<Production of support>
A JIS A 1050 aluminum plate having a thickness of 0.3 mm was grained with a rotating nylon brush using a pumice-water suspension as an abrasive. The surface roughness (centerline average roughness) at this time was 0.5 μm. After washing with water, a 10% aqueous sodium hydroxide solution was immersed in a solution warmed to 70 ° C., and etching was performed so that the amount of aluminum dissolved was 6 g / m ³ . After washing with water, it was neutralized by immersing in a 30% nitric acid aqueous solution for 1 minute and thoroughly washed with water. Then, electrolytic surface roughening was performed in a 0.7% nitric acid aqueous solution for 20 seconds using a rectangular wave alternating waveform voltage having an anode voltage of 13 volts and a cathode voltage of 6 volts. After dipping to wash the surface, it was washed with water. The roughened aluminum sheet was subjected to a porous anodic oxide film forming treatment using direct current in a 20% aqueous sulfuric acid solution. Electrolysis was performed at a current density of 5 A / dm ² and the electrolysis time was adjusted to produce a substrate having an anodic oxide film with a mass of 4.0 g / m ^{2 on} the surface. This substrate was treated in a vapor chamber saturated at 100 ° C. and 1 atm for 10 seconds to prepare a substrate (b) having a sealing rate of 60%. The substrate (b) was treated with a 2.5% by weight aqueous solution of sodium silicate at 30 ° C. for 10 seconds to make the surface hydrophilic, then the following undercoat solution 1 was applied, and the coating film was dried at 80 ° C. for 15 seconds to be lithographically printed. A plate support [B] was obtained. The coating amount of the coating film after drying was 15 mg / m ² .

<Formation of undercoat intermediate layer>
On the support [B] produced as described above, the following coating solution for forming an intermediate layer was applied, followed by drying at 80 ° C. for 15 seconds to provide an intermediate layer. The coating amount after drying was 15 mg / m ² .
(Undercoat 1)
・ 0.5 g of the following copolymer having a molecular weight of 28,000
・ Methanol 100g
・ Water 1g

<Formation of recording layer>
After applying the photosensitive solution I having the following composition to the obtained undercoated support [B] with a wire bar, it is dried in a drying oven at 150 ° C. for 40 seconds to obtain a coating amount of 1.3 g / m ^2. Thus, a lower layer was provided. After providing the lower layer, the coating liquid II having the following composition was applied with a wire bar to provide the upper layer. After coating, drying was performed at 150 ° C. for 40 seconds to obtain a photosensitive lithographic printing plate precursor for infrared laser in which the total coating amount of the lower layer and the upper layer was 1.7 g / m ² . This lithographic printing plate precursor has the multilayer structure shown in FIG.
(Photosensitive solution I)
・ Specific maleide resin A (copolymer 1) 3.5 g
0.15 g of a dye in which the counter anion of ethyl violet is 6-hydroxy-β-naphthalenesulfonic acid
・ Infrared absorber (the aforementioned cyanine dye A) 0.25 g
・ Bisphenolsulfone 0.3g
・ Tetrahydrophthalic acid 0.4g
・ Fluorine surfactant (Megafac F-780, trade name,
Dainippon Ink & Chemicals, Inc.) 0.02g
・ Methyl ethyl ketone 30g
・ Propylene glycol monomethyl ether 15g
・ Γ-Butyrolactone 15g
・ Surfactant listed in Table 1 Amount listed in Table 1 (expressed in mass%)
* Copolymer 1: a copolymer comprising 35 mol% N-phenylmaleimide, 30 mol% methacrylic acid and 35 mol% N- [2- (2-oxo-1-imidazolidinyl) ethyl] methacrylamide.

(Photosensitive solution II)
・ Novolak resin 0.68g
(M-cresol / p-cresol / phenol = 3/2/5,
Mw 8,000)
・ Infrared absorber (the aforementioned cyanine dye A) 0.045 g
・ Fluorine surfactant (Megafac F-780, trade name,
Dainippon Ink & Chemicals, Inc.) 0.03g
・ Methyl ethyl ketone 15.0g
-1-methoxy-2-propanol 30.0g

  The obtained lithographic printing plate precursor was evaluated as follows. The results are shown in Table 1.

<Evaluation of running residue>
The development starter conductivity value of 40 mS / cm and the equilibrium conductivity value of 45 mS / cm were input to the control unit of the automatic processor. The automatic processor was used to average the 50 plates per day for one month. Processed. During the exposure, the entire surface was exposed with a Trendsetter (trade name) manufactured by Creo at a beam intensity of 9 w and a drum rotation speed of 150 rpm.
One month later, the developer was removed from the developer tank and the situation was visually observed. As a result, no development residue was found.
AA: A state in which the developer is removed from the developer tank and visually confirmed to have no or almost no development residue B: A level in which developer residue is removed from the developer tank and visually confirmed to allow development residue to be easily observed C: Development tank The level at which development residue adheres to the plate when the plate is passed without removing the developer from the plate

<Evaluation of film reduction>
Evaluation of film reduction due to development of image area The unexposed lithographic printing plate precursor was then diluted with Fuji Film's automatic processor LP-940H with Fuji Film's developer DT-2 (1: 8). And a finisher FG-1 (diluted 1: 1) manufactured by Fuji Film Co., Ltd., and developed at a developer temperature of 32 ° C. and a development time of 12 seconds. The electric conductivity of the developer at this time was 43 mS / cm.
The optical density of the photosensitive layer before and after development was measured, and the relative density when the density obtained by subtracting the density of the aluminum support alone from the density before development was taken as 100% was expressed as the reduction in the developed film.
A: 90% or more A: 85% or more and less than 90% B: 80% or more and less than 85% C: Less than 80%

<Evaluation of printing durability>
A test pattern was drawn on the lithographic printing plate precursor in the form of an image with a Trend setter (trade name) manufactured by Creo at a beam intensity of 9 w and a drum rotation speed of 150 rpm. Thereafter, a PS processor LP940H (trade name) manufactured by Fuji Film Co., Ltd. charged with developer DT-2 (trade name) manufactured by Fuji Film Co., Ltd. (diluted to a conductivity of 43 mS / cm) was used. Development was performed at a development temperature of 30 ° C. and a development time of 12 seconds. This was continuously printed using a printing press Lislon (trade name) manufactured by Komori Corporation. At this time, the number of sheets that can be printed while maintaining a sufficient ink density was measured visually to evaluate the printing durability. The printing durability was shown as a relative value when the printing durability of Comparative Example 1 was 1.0. As the test pattern, a solid image (entire image portion) of 2 cm × 2 cm was used. According to the visual evaluation of the printed matter, the number of scumming or missing in the printing portion was determined as the number of finished prints. At this time, “1.0” was 40,000 sheets.
AA: 90% or more A: 85% or more and less than 90% B: 80% or more and less than 85% C: less than 80% <Evaluation of waste liquid concentration aptitude>
Using the waste liquid reduction device XR-2000 manufactured by Fuji Film Graphic Systems Co., Ltd., and the AF-A manufactured by Fuji Film Co., Ltd. diluted to 3% with water. Used to concentrate.
It evaluated from the concentration rate and the BOD value of distilled regenerated water.
AA: Concentration rate of 4 times or more and BOD value less than 300 mg / L A: Concentration rate of 3 times or more and less than 4 times and BOD value of less than 300 mg / L B: Concentration rate of 2 times or more and less than 3 times and BOD value Less than 300 mg / L C: Concentration rate 1 to 2 times and BOD value less than 300 mg / L D: Concentration rate 1 to 2 times and BOD value 300 mg / L or more

(Developer)
・ D sorbit 2.5% by mass
-Sodium hydroxide 0.85 mass%
・ Polyethylene glycol lauryl ether 0.5% by mass
(Mass average molecular weight 1,000)
・ Water 96.15% by mass

Softazoline LPB-R: trade name, amidobetaine type amphoteric surfactant,
Kawaken Fine Chemical Co., Ltd., Softazoline LAO: trade name, amidoamine oxide amphoteric surfactant,
Kawaken Fine Chemical Co., Ltd. New Coal B4SN: trade name, anionic surfactant,
Nippon Emulsifier Co., Ltd. R—O— (CH ₂ CH ₂ O) _n —SO ₃ Na (R: aryl group, n: integer)
Pelex NBL: trade name, anionic surfactant, sodium alkylnaphthalene sulfonate manufactured by Kao Corporation,
* 1: Content relative to the total solid content of the recording layer containing the surfactant. The same applies to the following tables.

  As is clear from the above table, the lithographic printing plate precursor according to the present invention has a significantly improved run-nigkas as compared with the comparative example, has sufficient performance without film loss, and has high printing durability. Indicated. From this result, it is understood that the lithographic printing plate precursor having a recording layer containing the amphoteric surfactant or anionic surfactant of the present invention realizes high developability as well as high printing durability.

(Example 2, comparative example 2)
The specific maleimide resin A used The copolymer 1 was changed to the copolymers 2 to 3, respectively, and the running residue, film reduction, and printing durability were evaluated in the same manner as in Example 1 above. As a result, in the same manner as in Example 1, the lithographic printing plate precursor (Example) using the amphoteric surfactant or the anionic surfactant according to the present invention uses any of the maleimide resins. It was confirmed that good performance was exhibited with respect to those not (Comparative Example). The results are shown in Table 2 below.
* Copolymer 2: Copolymer containing 35 mol% N-phenylmaleimide, 30 mol% methacrylic acid and 35 mol% N- [2- (2-oxo-1-imidazolinyl) ethyl] methacrylamide * Copolymer 3:35 Copolymer comprising mol% N-benzylmaleimide, 30 mol% methacrylic acid and 35 mol% N- [2- (2-oxo-1-imidazolidinyl) ethyl] methacrylamide

(Example 3, Comparative Example 3)
Moreover, although the example which contains specific maleimide resin A and an amphoteric surfactant or anionic surfactant in a lower layer was shown above, what was changed into the form shown to the above Table A, said Example As in 1 and 2, it was confirmed that the present invention has a high effect. In other words, the stencil printing plate precursor (Example) using the amphoteric surfactant or the anionic surfactant according to the present invention showed good results compared to the comparative example with respect to running residue, film reduction, and printing durability. It can be seen that good performance is exhibited with respect to the balance between developability and printing durability, compared to the case where no is used (comparative example).

DESCRIPTION OF SYMBOLS 1 Image recording layer 3 Undercoat layer 4 Support body 11 Recording layer upper layer 12 Recording layer lower layer 10 Planographic printing plate precursor

Claims (10)

An infrared-sensitive positive lithographic printing plate precursor having a recording layer in which a lower layer and an upper layer are arranged in this order on a support having a hydrophilic surface, wherein the upper layer and / or the lower layer are the following maleimide resins A lithographic printing plate precursor comprising A, an amphoteric surfactant and / or an anionic surfactant, and an infrared absorber in the same layer or in separate layers.
[Maleimide resin A:
Copolymer containing methacrylic acid, at least one selected from the group consisting of N-phenylmaleimide, N-cyclohexylmaleimide, and N-benzylmaleimide, and a monomer represented by the following general formula (a)]

(Wherein R ¹ is a hydrogen atom or a methyl group. X is an alkylene group having 2 to 12 carbon atoms, an oxyalkylene group having 4 to 8 carbon atoms, or —SiRa ₂ —. Ra is an alkyl group. And the two alkyl groups may be the same or different from each other, and m is an integer of 1 to 3.) 2. The lithographic printing plate precursor as claimed in claim 1, wherein the amphoteric surfactant is represented by any one of the following general formulas (I) to (III).

(In General Formulas (I) to (III), R ¹¹ represents an alkyl group having 6 to 24 carbon atoms or an alkyl group via a specific linking group. R ¹² and R ¹³ each independently have 1 to 5 carbon atoms. R ¹⁴ and R ¹⁵ each independently represents an alkyl group having 1 to 5 carbon atoms, provided that at least one of R ¹⁴ and R ¹⁵ has an acidic group or a salt thereof at the terminal, and L ¹¹ represents carbon. .X which represents a linking group having 1 to 4 ^- represents a carboxylate ion, sulfonate ion, sulfate ion, phosphonate or phosphate ions). The lithographic printing plate precursor as claimed in claim 1, wherein the anionic surfactant is represented by any one of the following formulas (IV) to (VI ) .

(In the general formula (IV) ~ (V I) , .D 11 R 1 6 is representative of the ^{.L 12} is a phenylene group or a single bond represents an alkyl group having 6 to 24 carbon ^atoms, E ^{11, F} 11 sulfonic acid Represents an ion or a salt thereof, or a sulfate ion or a salt thereof, R ¹⁷ represents an alkyl group having 4 to 18 carbon atoms, L ¹³ represents a phenylene group or a naphthylene group, and R ¹⁸ represents a phenyl group or a naphthyl group. L ¹⁴ represents a polyalkyleneoxy group .)   The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein m in the general formula (a) is 1 or 2.   The lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the surfactant is contained in an amount of 3 to 40 parts by mass with respect to 100 parts by mass of the maleimide resin A.   The lithographic printing plate precursor as claimed in any one of Claims 1 to 5, wherein the lithographic printing plate precursor as claimed in any one of claims 1 to 5 comprises, in order, an undercoat layer, a lower layer and an upper layer forming a recording layer.   The lithographic printing plate precursor as claimed in any one of claims 1 to 6, wherein the maleimide resin A is contained in a lower layer of the recording layer.   The lithographic printing plate precursor as claimed in any one of claims 1 to 7, wherein the amphoteric surfactant is contained in the same layer as the maleimide resin A.   The exposure process which image-exposes the recording layer of the lithographic printing plate precursor as described in any one of Claims 1-8, and the image development process which develops using alkaline aqueous solution of pH 11.0-13.5 are included in this order. A method for preparing a lithographic printing plate. The method of preparing a lithographic printing plate according to claim 9, wherein the aqueous alkaline solution contains an anionic surfactant or an amphoteric surfactant.

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