JP2010139551A - Alkali developer for photosensitive lithographic printing and plate making method of lithographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkali developer for photosensitive lithographic printing most suitable for developing a negative photosensitive lithographic printing plate having an aluminum support not subjected to silicate treatment. <P>SOLUTION: The alkali developer for photosensitive lithographic printing contains, based on the total mass of the developer, 0.2-5 mass% (in terms of solid content) of benzyl alcohol (a), 0.2-1.5 mass% (in terms of solid content) of a tetraalkylammonium hydroxide (b), and a polyoxyalkylene non-aryl type anionic surfactant (c). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an alkali developer used for a negative photosensitive lithographic printing plate, and further relates to a method for making a lithographic printing plate using the alkali developer.

  In offset printing, a shift to a new type of lithographic printing using computer technology and laser technology, which has been remarkably progressed in recent years, that is, so-called CTP (computer-to-plate) lithographic printing is proceeding at a rapid pace. Here, CTP (computer-to-plate) is a system for creating a printing plate by printing digital data edited by a computer directly on a printing plate material without using a film. In CTP, film production is omitted, so printing speed and cost can be reduced. Further, this CTP lithographic printing is advantageous in that the printing digital data is directly printed on the printing plate material without using a film, so that the image resolution is high and a good printed matter can be obtained. Such CTP lithographic printing plate materials include a negative type and a positive type. The negative type has an advantage that it generally has excellent printing durability and is frequently used. CTP lithographic printing plate materials are also variously distinguished by the type (wavelength) of the light source used for drawing. In recent years, semiconductor lasers in the near infrared or infrared region that can obtain high output have attracted attention as preferred light sources.

  Conventionally, a silicate-treated aluminum support has been used as a support for negative photosensitive lithographic printing plates (see, for example, JP-A-2006-39177 (Patent Document 1)). The use of the silicate-treated aluminum support has the advantage that the non-image area has good water retention in offset printing and is preferable in preventing the occurrence of background stains. On the other hand, when using a silicate-treated aluminum support in a negative photosensitive lithographic printing plate for near infrared laser, there is a problem that the adhesion between the photosensitive layer and the aluminum support is poor. This problem causes a serious problem that an image portion which is an exposed portion is lost during the development process, or printing durability is deteriorated when printing is performed after development.

  On the other hand, as a support for a negative photosensitive lithographic printing plate for a near-infrared laser, a method of using an aluminum support that has not been subjected to a silicate treatment has been studied (for example, JP-A-2007-264497). (See Patent Document 2). However, in the case of using an aluminum support that has not been subjected to silicate treatment, it is necessary to impart water retention to the non-image area, and it is necessary to remove the strongly adhering photosensitive layer. Processing with a strong alkaline developer having a high pH, which is an inorganic strong alkali developer containing a salt, is required. However, when developing with such an inorganic strong alkali developer containing silicate, there is a problem that alkali erosion of the image area occurs at the time of development, and problems such as ink adhesion or printing durability are likely to occur. . Furthermore, in order to solve this problem, a method using an aluminum support that has not been subjected to a silicate treatment and using an inorganic strong alkali developer not containing silicate as a developer is also considered (for example, JP, 2002-311593, A (patent documents 3) etc.). However, this method has a problem in that there is a defect in printing performance such that scumming tends to occur.

JP 2006-39177 A JP 2007-264497 A JP 2002-31593 A

  An object of the present invention is to solve the problems related to the development of the above-mentioned negative photosensitive lithographic printing plate for near infrared laser by improving the developer. That is, an object of the present invention is to provide an alkaline developer for photosensitive lithographic printing which is most suitable for developing a negative photosensitive lithographic printing plate having an aluminum support that has not been subjected to a silicate treatment.

In the present invention, benzyl alcohol (a) is 0.2 to 5% by mass based on the total mass of the developer,
Tetraalkylammonium hydroxide (b) in an amount of 0.2 to 1.5% by solid content based on the total mass of the developer, and a polyoxyalkylene non-aryl type anionic surfactant (c),
And an alkaline developer for photosensitive lithographic printing, which achieves the above object.

  The content of the polyoxyalkylene non-aryl type anionic surfactant (c) is preferably 0.5 to 15% by mass based on the total mass of the developer.

  The polyoxyalkylene non-aryl type anionic surfactant (c) is preferably a polyoxyalkylene glycol disulfonate.

［式中、Ｒ^１は、水素原子、炭素数１〜３０の炭化水素基、ＨＯＣＯＣＨ_２−、ＨＯＣＯＣＨ_２ＣＨ_２−を示し、
Ｒ^２は、水素原子、炭素数１〜７のアルキル基、炭素数７〜１２のアリール基、ＨＯＣＯＣＨ_２−、ＨＯＣＯＣＨ_２ＣＨ_２−、Ｈ_２ＮＣＯＣＨ_２−、ＨＳＣＨ_２−、Ｈ_２ＮＣＯＣＨ_２ＣＨ_２−、ＣＨ_３ＳＣＨ_２ＣＨ_２−、ＨＯＣＨ_２−、ＣＨ_３ＣＨ（ＯＨ）−、ＨＯＣ_６Ｈ_４ＣＨ_２−またはＨ_２Ｎ（ＣＨ_２）_４−を示し、
ｍは１〜１０の整数を示す。］
で示される、アミノカルボン酸またはそれらの塩類（ｄ）を現像液の全質量に対して０．０１〜２固形分質量％を含む。 The alkaline developer for photosensitive lithographic printing of the present invention is preferably further represented by the following formula:

[Wherein R ¹ represents a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, HOCOCH ₂ —, HOCOCH ₂ CH ₂ —,
R ² is a hydrogen atom, an alkyl group having 1 to 7 carbon atoms, an aryl group having 7 to 12 carbon atoms, HOCOCH ₂ —, HOCOCH ₂ CH ₂ —, H ₂ NCOCH ₂ —, HSCH ₂ —, H ₂ NCOCH ₂ CH _{2 -, CH 3 SCH 2 CH} 2 -, HOCH 2 -, CH 3 CH (OH) -, HOC 6 H 4 CH 2 - or _{H 2 N (CH 2) 4} - indicates,
m shows the integer of 1-10. ]
The aminocarboxylic acid or a salt thereof (d) represented by the formula (1) is contained in an amount of 0.01 to 2% by mass based on the total mass of the developer.

  The alkaline developer for photosensitive lithographic printing of the present invention preferably has a pH of 12-14.

The present invention also provides an exposure step of exposing a negative photosensitive lithographic printing plate using a near infrared laser,
Developing the exposed negative photosensitive lithographic printing plate using the alkaline developer for photosensitive lithographic printing described above,
A process for making a lithographic printing plate comprising:
The negative photosensitive lithographic printing plate has a support and a photosensitive layer,
The support is an anodized aluminum support that has not been subjected to a silicate treatment; and
The photosensitive layer contains a compound having an unsaturated double bond group and a urethane bond group, an alkali-soluble resin and a near-infrared absorbing dye, and the compound having an unsaturated double bond group and a urethane bond group in the photosensitive layer The content in is 10 to 80% by mass,
A method for making a lithographic printing plate is provided.

  By using the alkaline developer for photosensitive lithographic printing of the present invention, it is possible to obtain excellent printing performance such that ink repellency and halftone reproducibility are good in lithographic printing plate making. The alkaline developer for photosensitive lithographic printing of the present invention is suitable for development of a negative photosensitive lithographic printing plate having an aluminum support that has not been subjected to a silicate treatment. This is very suitable for developing a printing plate containing 10 to 80% by mass of a compound having a heavy bond group and a urethane bond group.

Photosensitive lithographic printing alkali developer The photosensitive lithographic printing alkali developer of the present invention includes:
Benzyl alcohol (a) 0.2-5 solids mass%,
Tetraalkylammonium hydroxide (b) 0.2 to 1.5 solids mass%, and polyoxyalkylene non-aryl type anionic surfactant (c),
Is included at least.

Benzyl alcohol (a)
The alkaline developer for photosensitive lithographic printing of the present invention contains benzyl alcohol (a). This benzyl alcohol (a) has an unsaturated double bond group and a urethane bond group contained in a negative photosensitive lithographic printing plate that is suitably developed using the alkaline developer for photosensitive lithographic printing of the present invention. It plays the role of stably dispersing and dissolving the compound in the developer. The benzyl alcohol (a) further has the advantages of high solubility in a photosensitive lithographic printing alkali developer, low vapor pressure, and low scattering to the environment.

  Content of benzyl alcohol (a) is 0.2-5 solid mass% with respect to the total mass of the alkali developing solution for photosensitive lithographic printing. The content is preferably 0.3 to 3% by mass. When the content of benzyl alcohol (a) is less than 0.2% by mass, the elution failure of the non-image area is remarkable and soiling occurs. On the other hand, when the content of benzyl alcohol (a) exceeds 5% by mass, the non-image area is excessively eluted (overdevelopment), resulting in poor halftone reproducibility and poor developability.

Tetraalkylammonium hydroxide (b)
The alkali developer for photosensitive lithographic printing of the present invention contains tetraalkylammonium hydroxide (b). By containing tetraalkylammonium hydroxide (b), the pH of the alkaline developer for photosensitive lithographic printing is adjusted to a pH range of 12 to 14 suitable for development.
Moreover, this tetraalkylammonium hydroxide (b) does not have a metal ion. The absence of metal ions prevents the elution of aluminum ions from the aluminum support, prevents the precipitation of inorganic solids caused by aluminum hydroxide, etc. To make it easier.

  For example, tetraalkylammonium hydroxide (b) is represented by the following formula:

[Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents a linear or branched alkyl group having 1 to 8 carbon atoms which may have a hydroxyl group. ]
The compound shown by these is mentioned.

  Specific examples of the tetraalkylammonium hydroxide (b) include, for example, tetramethylammonium hydroxide, trimethylethylammonium hydroxide, tetraalkylammonium hydroxide compounds such as tetraethylammonium hydroxide, and trimethylhydroxide (2-hydroxy). And tetra-substituted alkylammonium hydroxide compounds having 1 to 4 hydroxyl groups such as ethyl) ammonium (choline), methyl trihydroxyethylammonium hydroxide, and dimethyldihydroxyethylammonium hydroxide.

  The tetraalkylammonium hydroxide (b) may be added, for example, in the form of a carbonate or hydrogen carbonate when preparing an alkaline developer for photosensitive lithographic printing.

  The content of tetraalkylammonium hydroxide (b) is 0.2 to 1.5 solids by mass based on the total mass of the photosensitive lithographic printing alkali developer. This content is preferably 0.2 to 1.4 solids by mass. If the content is less than 0.2% by mass, the elution failure of the non-image area is remarkable and the background stains occur. On the other hand, if it exceeds 1.5% by mass, the non-image area is excessively eluted (overdevelopment), resulting in poor halftone reproducibility and poor developability.

  In the alkaline developer for photosensitive lithographic printing of the present invention, monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-ethylethanolamine are combined with the tetraalkylammonium hydroxide (b). An alkanolamine such as may be further used. By using these alkanolamines together, it is possible to adjust the elution property of the non-image area to an appropriate range.

Polyoxyalkylene non-aryl type anionic surfactant (c)
The alkali developer for photosensitive lithographic printing of the present invention contains a polyoxyalkylene non-aryl type anionic surfactant (c). By including the polyoxyalkylene non-aryl type anionic surfactant (c), the wettability of the alkaline developer for photosensitive lithographic printing to the photosensitive layer of the negative photosensitive lithographic printing plate is improved. This also promotes penetration of the photosensitive lithographic printing alkali developer into the photosensitive layer. Furthermore, as the most effective action, a compound having an unsaturated double bond group and a urethane bond group has an essential property that it is difficult to disperse and dissolve in a developer due to the high cohesive force of the urethane bond group. However, in the development of the photosensitive layer containing the compound having an unsaturated double bond group and a urethane bond group, the presence of the polyoxyalkylene non-aryl type anionic surfactant (c) causes the development residue in the developer. Resin components having low solubility, such as compounds having an unsaturated double bond group and a urethane bond group, are also easily dispersed and stabilized, and exhibit stable and uniform developer properties even when continuously developed. In addition, it is assumed that the surface characteristics of the photosensitive layer of the negative photosensitive lithographic printing plate are improved by the alkaline developer for photosensitive lithographic printing of the present invention. Ink fillability is improved.

It is an important point that the surfactant contained in the alkaline developer for photosensitive lithographic printing of the present invention is a polyoxyalkylene non-aryl type anionic surfactant (c). In other words, these polyoxyalkylene alkyl ether type anionic surfactants and polyoxyalkylene glycol type anionic surfactants are negative photosensitive lithographic printing that is preferably developed using the alkaline developer for photosensitive lithographic printing of the present invention. It has a role of particularly stably dispersing and dissolving the compound having an unsaturated double bond group and a urethane bond group contained in the plate in the developer. However, in the case of continuously prepress-developing a photosensitive layer containing a compound having an unsaturated double bond group and a urethane bond group using a surfactant having no polyoxyalkylene structure or an aryl type anionic surfactant. Is not a remarkable phenomenon at the beginning of continuous plate-making development, but with the passage of continuous plate-making development time, a resin component having low solubility such as a development residue, a compound having an unsaturated double bond group and a urethane bond group becomes stable. A problem arises in that the resin cannot be completely dispersed or dissolved, and is released and deposited as a resinous floating substance, which adheres to the plate-making surface and causes printing defects.

  In particular, the resin or oligomer component forming the photosensitive layer of the present invention does not retain in the molecule a functional group that imparts water solubility by forming a salt, such as a hydroxycarbonyl group, or the retained amount is water-soluble even if retained. In the case of a compound having a urethane bond and an ethylenic double bond having a very high cohesive force on the surface, particularly in order to stably disperse and dissolve in a developer, this anionic surfactant This characteristic effect makes it possible to stably disperse and dissolve the compound in the developer.

（式中、Ｘは酸素原子、ＣＯＯ、ＣＯＮＲ^１(ここでＲ^１は水素原子または炭素原子数１〜４のアルキル基を表し、Ｙは水素原子、直鎖又は分岐鎖の炭素原子数６〜３０のアルキル基、アルケニル基又はアシル基を表し、Ｗは水素原子又はメチル基を表し、Mは水素原子、アルカリ金属原子（例えば、ナトリウム原子またはカリウム原子）又はアンモニウム基を表し、ｎは１〜１，０００の整数を表す。）
で表されるポリオキシアルキレンアルキルエーテル、エステル及びアミド型などの硫酸エステル塩類；
上記一般式（Ａ）において、Xが酸素原子で、Ｙが−ＳＯ_３Ｍ基であるポリオキシアルキレングリコールジスルホン酸塩類；
一般式（Ｂ）

（式中、Ｚは水素原子、直鎖又は分岐鎖の炭素原子数６〜３０のアルキル基、アルケニル基又はアシル基を表し、Ｗは水素原子又はメチル基を表し、Ｍは水素原子、又はアルカリ金属原子を表し、ｎは１〜１００の整数、ｍは１、２、又は３である。）
で表されるポリオキシアルキレンアルキルエーテルリン酸エステル塩類；または
上記一般式（Ｂ）において、ＺがＰＯ_４Ｍ_２基であるポリオキシアルキレングリコールジリン酸エステル塩類；
などが挙げられる。 Preferable specific examples of the polyoxyalkylene non-aryl type anionic surfactant (c) include, for example, the general formula (A),

(Wherein X represents an oxygen atom, COO, CONR ¹ (wherein R ¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, Y represents a hydrogen atom, a straight chain or branched chain carbon atom having 6 to 6 carbon atoms) 30 represents an alkyl group, an alkenyl group or an acyl group, W represents a hydrogen atom or a methyl group, M represents a hydrogen atom, an alkali metal atom (for example, a sodium atom or a potassium atom) or an ammonium group, and n represents 1 to 1 Represents an integer of 1,000.)
Sulfate esters such as polyoxyalkylene alkyl ether, ester and amide type represented by:
In the above general formula (A), polyoxyalkylene glycol disulfonates in which X is an oxygen atom and Y is a —SO ₃ M group;
General formula (B)

(In the formula, Z represents a hydrogen atom, a linear or branched alkyl group having 6 to 30 carbon atoms, an alkenyl group, or an acyl group, W represents a hydrogen atom or a methyl group, and M represents a hydrogen atom or an alkali. Represents a metal atom, n is an integer of 1 to 100, and m is 1, 2 or 3.)
Or a polyoxyalkylene glycol diphosphate salt in which Z is a PO ₄ M ₂ group in the general formula (B);
Etc.

As the polyoxyalkylene non-aryl type anionic surfactant (c), a compound having two sulfonic acid groups is preferable. Among these, polyoxyalkylene diglycol disulfonic acid sodium salt is more preferably used.

  A commercially available product can also be used as the polyoxyalkylene non-aryl type anionic surfactant (c). For example, Nippon Emulsifier Co., Ltd. New Coal 200 series (for example, New Coal 240, 290-A, 290-K, 290-KS, 291-M, 291-PG, 291-GL, 292-PG, 293, 297), Newcall 1000 series and 2000 series (for example, Newcall 1000-FCP, 1020-SN, 2308-SF, 2320-SN, 2360-SN, 1305-SN, 1330-SF, 1703-SFD, 1525-SFC), and Antox (for example, Antox EHD-400, EHD-PNA) and the like can be mentioned.

  The content of the polyoxyalkylene non-aryl type anionic surfactant (c) with respect to the total mass of the alkali developer for photosensitive lithographic printing is preferably 0.5 to 15% by solid content, and 1.0 to 12%. More preferably, it is solid mass%. When the content is 0.5% by mass or more, the wettability of the non-image area with respect to the developer is improved, and the risk of elution failure is reduced. Further, when the content is 15% by mass or less, the risk of excessive elution (overdevelopment) of the non-image area is reduced.

Aminocarboxylic acids or their salts (d)
The alkaline developer for photosensitive lithographic printing of the present invention more preferably contains an aminocarboxylic acid or a salt thereof (d) in addition to the components (a) to (c). Due to the fact that the aminocarboxylic acid or a salt thereof (d) is contained in the alkaline developer for photosensitive lithographic printing, it is caused by the resin component or the near infrared absorbing dye contained in the photosensitive layer of the negative photosensitive lithographic printing plate The generation of insoluble matter can be suppressed, and the problem that these insoluble matters adhere to the planographic printing plate can be suppressed. Accordingly, there is an advantage that the development can be stably performed for a long time.

  Here, aminocarboxylic acid means the following formula

[Wherein R ¹ represents a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, HOCOCH ₂ —, HOCOCH ₂ CH ₂ —,
R ² is a hydrogen atom, an alkyl group having 1 to 7 carbon atoms, an aryl group having 7 to 12 carbon atoms, HOCOCH ₂ —, HOCOCH ₂ CH ₂ —, H ₂ NCOCH ₂ —, HSCH ₂ —, H ₂ NCOCH ₂ CH _{2 -, CH 3 SCH 2 CH} 2 -, HOCH 2 -, CH 3 CH (OH) -, HOC 6 H 4 CH 2 - or _{H 2 N (CH 2) 4} - indicates,
m shows the integer of 1-10. ]
Means a compound represented by Here, the hydrocarbon group in R ¹ may be linear or branched, and may be a saturated group or an unsaturated group. The alkyl group for R ² may also be linear or branched. Examples of aminocarboxylic acid salts include alkali metal salts (for example, sodium salt, potassium salt and lithium salt), ammonium salts and amine salts of aminocarboxylic acids represented by the above formula.

In the above formula, R ¹ is preferably a hydrogen atom, a linear saturated hydrocarbon group having 1 to 15 carbon atoms, or HOCOCH ₂ —. R ² is preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. M is preferably an integer of 1 to 3. When m is 2 or 3, R ² may be the same or different.

  Specific examples of aminocarboxylic acid include, for example, glycine, alanine, leucine, isoleucine, phenylalanine, aspartic acid, glutamic acid, iminodiacetic acid, asparagine, cysteine, glutamine, methionine, serine, threonine, tyrosine, valine, lysine, β-alanine, Examples thereof include β, β′-iminodipropionic acid, and these N-terminal substituent introduction products. The aminocarboxylic acids or their salts (d) can be prepared according to a conventional method. Moreover, it can also be obtained as a commercial product such as, for example, the trade name Piionin C-158 (manufactured by Takemoto Yushi Co., Ltd.).

  When the aminocarboxylic acid or a salt thereof (d) is contained, the content is preferably 0.01 to 2% by mass based on the total mass of the photosensitive lithographic printing alkali developer. The content is more preferably 0.05 to 1% by mass. When the content of the aminocarboxylic acid or a salt thereof (d) is less than 0.01% by mass, the effect of adding the aminocarboxylic acid or a salt thereof (d) may not be obtained. Further, if the content of aminocarboxylic acid or a salt thereof (d) exceeds 2% by mass, excessive elution of the non-image area (over-development) results in poor halftone reproducibility and poor developability. There is a risk of becoming.

Other Components In addition to the above components, the alkaline developer for photosensitive lithographic printing of the present invention may contain additives as necessary. Examples of additives included include buffering agents such as phosphoric acid and phosphate; chelating agents such as ethylenediaminetetraacetic acid and diethylenetetraminepentaacetic acid; ethanol, propanol, isopropanol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, and the like. Various alcohols; Hydroquinone, resorcin, sulfurous acid or inorganic salt-based reducing agent such as sodium or potassium hydrogensulfite; Organic carboxylic acid; Antifoaming agent; Hard water softening agent;

  The alkaline developer for photosensitive lithographic printing of the present invention preferably has a pH of 12-14. In addition, pH here is pH in 20 degreeC. When pH is 12-14, there exists an advantage that the outstanding developability can be ensured. When the pH is less than 12, there is a possibility that poor elution of the non-image area may occur, which may cause scumming during printing. The alkaline developer for photosensitive lithographic printing of the present invention contains tetraalkylammonium hydroxide (b) which is a strong organic alkali compound. Therefore, even when the pH is as high as 12 to 14, development at a high pH caused by a strong inorganic alkali compound such as an alkali metal hydroxide or alkali metal silicate contained in a conventional developer. There is an advantage that the image portion is not lost or damaged due to the excessive phenomenon. Furthermore, there is an advantage that the etching damage to the aluminum support constituting the negative photosensitive lithographic printing plate is small.

Preparation of alkaline developer for photosensitive lithographic printing The alkaline developer for photosensitive lithographic printing of the present invention can be prepared by dissolving and dispersing the above components in an aqueous medium. As an aqueous medium used for preparing the photosensitive developer for photosensitive lithographic printing, ion exchange water, deionized water, distilled water, clean water and the like can be used. Moreover, in the preparation of the alkali developer for photosensitive lithographic printing, a water-miscible organic solvent such as a lower alcohol can be used in combination as necessary. The lower alcohol here does not contain benzyl alcohol.

Plate making method of lithographic printing plate The plate making method of the lithographic printing plate of the present invention,
An exposure process for exposing a negative photosensitive lithographic printing plate using a near-infrared laser;
Developing the exposed negative photosensitive lithographic printing plate using the alkaline developer for photosensitive lithographic printing,
It is a method including.

Negative photosensitive lithographic printing plate The negative photosensitive lithographic printing plate used in the plate making method is a printing plate having a support and a photosensitive layer. This support is an anodized aluminum support that has not been subjected to a silicate treatment. The photosensitive layer contains a compound having an unsaturated double bond group and a urethane bond group, an alkali-soluble resin, and a near-infrared absorbing dye.

The support constituting the support negative photosensitive lithographic printing plate is an anodized aluminum support. The aluminum support is preferably an anodized aluminum support that has been mechanically roughened, chemically or electrically etched and then anodized. As a method for mechanically roughening, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. As a method of chemically etching, there is a method of etching with an acid or an alkali, and as an acid to be used, there are nitric acid, sulfuric acid, phosphoric acid, chromic acid, hydrofluoric acid, borohydrofluoric acid, etc. Includes sodium hydroxide, sodium carbonate, sodium phosphate, potassium hydroxide, lithium hydroxide and the like. As a method of electrically etching, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. As a method of anodizing, there is a method in which an electric current is passed through aluminum as an anode in one or two or more aqueous solutions of inorganic acids such as phosphoric acid, sulfuric acid and chromic acid, and organic acids such as oxalic acid.

  The anodized aluminum support used in the present invention is not subjected to silicate treatment. Here, the “silicate treatment” is a treatment widely used as a hydrophilization treatment, and a treatment for hydrophilizing an aluminum support using an alkali metal silicate (sodium silicate, potassium silicate, lithium silicate, etc.). Is the method. In general, silicate treatment of an anodized aluminum support is a preferred treatment for increasing water retention. However, the adhesion between the photosensitive layer and the aluminum support is lowered by the silicate treatment. In the plate making method of the present invention, an anodized aluminum support that has not been subjected to such a silicate treatment is used. When the components described in detail below are contained in the photosensitive layer, strong adhesion between the photosensitive layer and the anodized aluminum support is exhibited, and excellent water retention is also obtained. The photosensitive lithographic printing alkali developer is suitably used for developing such a negative photosensitive lithographic printing plate.

  The anodized aluminum support preferably has a thickness of 0.1 to 1.6 mm, preferably 0.25 to 0.55 mm. If the thickness of the aluminum support is less than 0.1 mm, it may break when handling a printing plate material or printing plate, especially when being carried by a human hand. On the other hand, if the thickness exceeds 1.6 mm, the cost of the printing plate material increases, and the printing plate material may become heavy and the frequency of jamming in the exposure apparatus may increase.

The photosensitive layer constituting the photosensitive layer negative photosensitive lithographic printing plate contains a compound having an unsaturated double bond group and a urethane bond group, an alkali-soluble resin and a near-infrared absorbing dye. The photosensitive layer preferably further contains a halomethyl group-containing compound and an organic boron anion compound.

Examples of the compound having an unsaturated double bond group and a urethane bond group contained in the compound photosensitive layer having an unsaturated double bond group and a urethane bond group include urethane poly (meth) acrylate. The urethane poly (meth) acrylate is obtained by reacting the isocyanurate body of the compound (1) having two or more isocyanate groups in the molecule with the compound (2) having a hydroxyl group and two or more (meth) acryloyl groups, Alternatively, the compound (1) having two or more isocyanate groups in the molecule and the compound (3) having two or more hydroxyl groups in the molecule are reacted to further have a hydroxyl group and two or more (meth) acryloyl groups. It can be prepared by reacting (2).

  As the compound (1), those having three or more isocyanate groups in the molecule are preferably used. Specific examples of the compound (1) include isocyanurate bodies, burette bodies, and adduct bodies of diisocyanates. In addition, triisocyanates such as 2,4,6-tolylene triisocyanate and 2,4,4'-triisocyanate diphenyl ether can be used. Most preferred are isocyanurates of diisocyanates, which have a large effect on printing durability (abrasion resistance and scratch resistance) and tend to reduce the adhesiveness of the surface of the photosensitive layer. Diisocyanates that can be used include aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, but aliphatic diisocyanates and alicyclic diisocyanates are preferred from the viewpoint of the balance between elongation and tensile strength related to printing durability. . Examples of preferred diisocyanates include hexamethylene diisocyanate, lysine diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate, 1,3- (isocyanatomethyl). ) Cyclohexane, isophorone diisocyanate, trimethylhexamethylene diisocyanate, dimer acid diisocyanate, methylene diisocyanate, ethylene diisocyanate, butylene diisocyanate, propylene diisocyanate, octadecylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,10-decanmethylene diisocyanate, 1, Examples include 3-cyclohexylene diisocyanate.Moreover, the above-mentioned diisocyanates can also be used directly as the compound (1).

  The compound (2) having a hydroxyl group and two or more (meth) acryloyl groups in the molecule to be reacted with the compound (1) is not particularly limited. For example, 1 of the hydroxyl groups of a polyol having three or more hydroxyl groups in the molecule. Examples include poly (meth) acrylates in which at least one is left and the rest is esterified with (meth) acrylic acid. Further, by adding (meth) acrylic acid to a glycidyl ester of (meth) acrylate, a compound having two (meth) acryloyl groups and a hydroxyl group generated by the reaction of glycidyl and an acid is obtained.

  The polyol having three or more hydroxyl groups in the molecule is not particularly limited, but pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolpropane, ditrimethylolpropane, trimethylolethane, ditrimethylolethane, ditrimethylolbutane. Polyols such as glycerin, diglycerin and trishydroxyaminomethane; alkylene oxide-modified or lactone-modified polyols obtained by adding ethylene oxide, propylene oxide, ε-caprolactone, γ-butyrolactone, etc. to these , And ethers of the above polyols and ethers of these polyols and diols. The diol used in this case is not particularly limited, but ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,5-pentanediol, 1, Examples include 4-hexanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, and triethylene glycol. In addition, the diols described above can also be used directly for the compound (3) having two or more hydroxyl groups in the molecule to be reacted with the compound (1).

  A compound having an unsaturated double bond group and a urethane bond group can be produced, for example, as follows. The compound (1) and the compound (2) are reacted at a temperature of 60 to 70 ° C. in the presence of a catalyst (for example, 1000 ppm of n-butyltin dilaurate) at a blending ratio in which an isocyanate group and a hydroxyl group are equivalent. . A compound having an unsaturated double bond group and a urethane bond group is obtained by reacting until the isocyanate group of the reaction mixture is no longer absorbed by the infrared absorption spectrum.

  Specific examples of the compound having an unsaturated double bond group and a urethane bond group that can be particularly preferably used include the following compounds.

  In the present invention, the content of the compound having an unsaturated double bond group and a urethane bond group is preferably 10 to 80% by mass based on the total solid content of the photosensitive layer, and preferably 15 to 78 solids. More preferably, the content is% by mass. If the content is less than 10% by mass, the adhesion to an aluminum support that has not been subjected to silicate treatment may be poor. On the other hand, if the solid content exceeds 80% by mass, the adhesion to the support becomes too strong, and the elution failure becomes remarkable, which may make it impossible to use.

  By including the compound having the urethane bond and the ethylenic double bond in the photosensitive layer, it is possible to achieve both balance between the adhesion of the photosensitive layer to the aluminum support and the elution of the non-image area. As a result, the anodized aluminum support that has not been subjected to the silicate treatment and the photosensitive layer are brought into close contact with each other with appropriate strength, and the background stain of the non-image area after development is improved. Further, by improving the occurrence of scumming, the development is preferably performed in the development step using the photosensitive lithographic printing alkali developer.

  In addition to the compound having an unsaturated double bond group and a urethane bond group, the photosensitive layer may contain a conventionally used ethylenically unsaturated polymerizable compound as necessary. The ethylenically unsaturated polymerizable compound other than the compound having an unsaturated double bond group and a urethane bond group is not particularly limited, but monofunctional (meth) acrylate, bifunctional or higher polyfunctional (meth) acrylate, etc. Is used. For example, acrylic acid, methacrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meta ) Acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, n-decyl (meth) acrylate, lauryl (meth) acrylate, n -Tridecyl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol mono (meth) acrylate, propylene glycol mono (meth) acrylate, diethylene glycol mono (meth) acrylate, dipropylene glycol mono ( ) Acrylate, polyethylene glycol mono (meth) acrylate having a molecular weight of 200-1000, polypropylene glycol mono (meth) acrylate having a molecular weight of 200-1000, polyethylene glycol monomethyl ether mono (meth) acrylate having a molecular weight of 200-1000, having a molecular weight of 200-1000 Polypropylene glycol monomethyl ether mono (meth) acrylate, polyethylene glycol monoethyl ether mono (meth) acrylate having a molecular weight of 200 to 1000, polypropylene glycol monoethyl ether mono (meth) acrylate having a molecular weight of 200 to 1000, n-butoxyethyl (meth) acrylate , Phenoxyethyl (meth) acrylate, 2-phenoxypropyl (meth) acrylate, cyclohexyl (Meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate, allyl (meth) acrylate, benzyl (meth) acrylate, tribromophenyl (meth) acrylate, 2,3-dichloropropyl (meth) acrylate, 3 -Chloro-2-hydroxypropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, Nt-butylaminoethyl (meth) acrylate, acrylamide, N , N-dimethylacrylamide, N, N-diethylacrylamide, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,3-propanediol di (meth) acrylate, 1,4- Butanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, glycerin di (meth) Examples include acrylate, glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, and trimethylolethane tri (meth) acrylate. Preferable examples include tri (meth) acrylic acid esterified with a compound obtained by etherifying polyols such as pentaerythritol, trimethylolpropane, trimethylolethane, trimethylolbutane, trishydroxyaminomethane, and glycerin. ) Acrylate, tetra (meth) acrylate, and the like, and tri (meth) acrylate, tetra (meth) acrylate, etc. obtained by esterifying a compound obtained by etherifying the aforementioned polyol and diol with (meth) acrylic acid. it can. More preferred are ditrimethylolpropane tetra (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylolethanetetra (meth) acrylate, ditrimethylolethanetri (meth) acrylate, pentaerythritol and trimethylolpropane. Tri (meth) acrylates, tetra (meth) acrylates, and the like of etherified products are exemplified.

Examples of the alkali-soluble resin contained in the alkali-soluble resin photosensitive layer include a resin having a carboxylic acid in the side chain, a resin having a carboxylic acid and an ethylenically unsaturated group in the side chain, or a mixture thereof. The ethylenically unsaturated group is introduced by reacting a part of the carboxylic acid in the side chain of the alkali-soluble resin with an epoxy group-containing ethylenically unsaturated compound. As said epoxy-group-containing ethylenically unsaturated compound, in patent 2758737, it describes as a compound (III) (Compound which has an epoxy group and (meth) acryloyl or (it may have a methyl substituent) vinyl group). Described as an alicyclic epoxy group-containing unsaturated compound (a compound having one radical polymerizable unsaturated group and an alicyclic epoxy group in one molecule) in Japanese Patent No. 2762775. Known compounds can be used, but preferred are glycidyl (meth) acrylate and (meth) acrylate having an alicyclic epoxy group.

  Specific examples of the alkali-soluble resin include (meth) acrylic acid, 2-succinoyloxyethyl methacrylate, 2-malenoyloxyethyl methacrylate, 2-phthaloyloxyethyl methacrylate, 2-methacrylic acid 2- A resin obtained by homopolymerizing an unsaturated carboxylic acid such as hexahydrophthaloyloxyethyl, maleic acid, fumaric acid, itaconic acid, crotonic acid or the like, or one of these unsaturated carboxylic acids and vinyl monomers having no carboxyl group Examples thereof include resins obtained by copolymerizing the above.

As a vinyl monomer having no carboxyl group,
(I) Hydroxyl group-containing monomer: For example, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, allyl alcohol, methallyl alcohol, N- (4-hydroxy Phenyl) acrylamide or N- (4-hydroxyphenyl) methacrylamide, o-, m-, p-hydroxystyrene, o-, m-, p-hydroxyphenyl-acrylate or -methacrylate;
(II) alkyl acrylate or methacrylate: for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, propyl (meth) acrylate, acyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl acrylate, 2-chloroethyl acrylate;
(III) Polymerizable amide: For example, acrylamide, methacrylamide, N-methylol acrylamide, N-methylol methacrylamide, N-ethyl acrylamide, N-hexyl acrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, Acrylamide or methacrylamide such as N-nitrophenylamide, N-ethyl-N-phenylacrylamide;

(IV) Nitrogen-containing alkyl acrylate or methacrylate: for example, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate;
(V) Vinyl ethers: For example, ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether, phenyl vinyl ether;
(VI) vinyl esters: for example, vinyl acetate, vinyl chloroacetate, vinyl butyrate, vinyl benzoate;

(VII) Styrenes: for example, styrene, α-methylstyrene, methylstyrene, chloromethylstyrene;
(VIII) Vinyl ketones: For example, methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, phenyl vinyl ketone;
(IX) Olefins: for example, ethylene, propylene, isobutylene, butadiene, isoprene;

(X) glycidyl (meth) acrylate;
(XI) polymerizable nitrile: for example, acrylonitrile, methacrylonitrile;
(XII) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine:
(XIII) zwitterionic monomers: N, N-dimethyl-N-methacryloxyethyl-N- (3-sulfopropyl) -ammonium-betaine, N, N-dimethyl-N-methacrylamidepropyl-N- ( 3-sulfopropyl) -ammonium-betaine, 1- (3-sulfopropyl) -2-vinylpyridinium-betaine; and the like.

  Maleic anhydride is copolymerized with styrene, α-methylstyrene, etc., and maleic anhydride is half-esterified with monohydric alcohols such as methanol, ethanol, propanol, butanol, hydroxyethyl (meth) acrylate, or hydrolyzed with water. Also included are resins that have been removed.

  Furthermore, novolac epoxy acrylate resin, bisphenol epoxy resin, etc., (meth) acrylic acid, 2-succinoloyloxyethyl methacrylate, 2-malenoyloxyethyl methacrylate, 2-phthaloyloxyethyl methacrylate, methacrylic acid 2 -After adding unsaturated carboxylic acid such as hexahydrophthaloyloxyethyl, maleic acid, fumaric acid, itaconic acid, crotonic acid, or saturated carboxylic acid such as acetic acid, propionic acid, stearic acid, maleic anhydride, anhydrous Resins modified with acid anhydrides such as itaconic acid, tetrahydrophthalic anhydride, and phthalic anhydride are also included.

  Among them, acrylic resins are preferable from the viewpoint of ease of synthesis and compatibility with a compound having an unsaturated double bond group and a urethane bond group, and specific examples (preferred examples) thereof include methacrylic acid. Methyl / methacrylic acid copolymer, methyl methacrylate / methyl acrylate / methacrylic acid copolymer, benzyl methacrylate / methyl methacrylate / 2-ethylhexyl methacrylate copolymer, methyl methacrylate / n-butyl methacrylate / acrylic 2-ethylhexyl acid / methacrylic acid copolymer, styrene / acrylic acid copolymer, styrene / methacrylic acid copolymer, styrene / methyl methacrylate / methyl acrylate / methacrylic acid copolymer, styrene / methyl methacrylate / methacrylic acid 2-hydroxyethyl acid / methacrylic acid copolymer, Le methyl / acrylate n- butyl / 2-ethylhexyl acrylate / methacrylic acid copolymer, methyl methacrylate / acrylic acid n- butyl / 2-ethylhexyl acrylate / styrene / methacrylic acid copolymer and the like.

  Moreover, it is also possible to mix and use an alkali-soluble resin having an ethylenically unsaturated group in the side chain. Examples of such an alkali-soluble resin having an ethylenically unsaturated group in the side chain include, for example, all of the carboxylic acid of an alkali-soluble resin having a carboxylic acid, an epoxy group-containing ethylenically unsaturated compound (glycidyl (meth) acrylate). , 3,4-epoxycyclohexylmethyl (meth) acrylate, etc.) resin reacted with an epoxy group, a resin having a hydroxyl group and an alkali-insoluble resin reacted with an isocyanate group of an ethylenically unsaturated compound having an isocyanate group Etc. There is no particular problem even if a non-alkali-soluble resin having an ethylenically unsaturated group in the side chain is synthesized and used by other methods.

  If a mixture of these resins and an alkali-soluble resin is alkali-soluble as a result, it can be regarded as an alkali-soluble resin as a whole without any particular problem. The resin properties in that case are regarded as a mixture.

  The alkali-soluble resin has an acid value of 30 to 150 KOH · mg / g, preferably 50 to 130 KOH · mg / g, and a weight average molecular weight of 5,000 to 200,000, preferably 10,000 to 200,000. It is desirable. When the acid value of the alkali-soluble resin is less than 30 KOH · mg / g, the alkali developability becomes insufficient. When the acid value is more than 150 KOH · mg / g, the alkali developability is sufficient, but the film is reduced and the image persistence is reduced. Deteriorate.

  When the weight-average molecular weight of the alkali-soluble resin is less than 5,000, the printing durability is lowered, and when the solid-holding property of a product such as a printing plate material is required, the solid-holding property is lowered. Developability is lowered.

  The compounding ratio of the compound having an unsaturated double bond group and a urethane bond group: alkali-soluble resin is 80:20 to 10:90, preferably 78:22 to 15:85, more preferably 60:40 to 90: 10. When the alkali-soluble resin is less than 20% by mass, the alkali developability is low and the solid retention is deteriorated, and when it exceeds 90% by mass, the printing durability is lowered.

The near infrared absorbing dye contained in the near infrared absorbing dye photosensitive layer is a compound having absorption in a wavelength region of 600 to 1100 nm. Examples of near-infrared absorbing dyes include naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, cyanine dyes, polymethine dyes, and the like, but are particularly limited as long as they are known to those skilled in the art as sensitizing dyes. Not. Among them, cyanine dyes and polymethine dyes are preferable, and those having a maximum absorption wavelength at 800 to 860 nm are particularly preferable. Near-infrared absorbing dyes can be blended alone or in combination.

  Specific examples of the near infrared absorbing dye include those exemplified below, but are not limited thereto.

で表される１−エチル−４−[５−(１−エチル−４(１Ｈ)−キノリニリデン)−１，３−ペンタジエニル]キノリニウムアイオダイド（８１４ｎｍ；ＭｅＯＨ）、以下の式： Quinoline cyanine dyes, such as the following formula:

1-ethyl-4- [5- (1-ethyl-4 (1H) -quinolinylidene) -1,3-pentadienyl] quinolinium iodide (814 nm; MeOH) represented by the following formula:

で表される１−エチル−２−[７−(１−エチル−２(１Ｈ)−キノリニリデン)−１，３，５−ヘプタトリエニル]キノリニウムアイオダイド（８１７ｎｍ；ＭｅＯＨ）；

1-ethyl-2- [7- (1-ethyl-2 (1H) -quinolinylidene) -1,3,5-heptatrienyl] quinolinium iodide (817 nm; MeOH);

で表される８−[(６，７−ジヒドロ−２，４−ジフェニル−５Ｈ−１−ベンゾピラン−８−イル)メチレン]５，６，７，８−テトラヒドロ−２，４−ジフェニル−１−ベンゾピリリウムパークロレート（８４０ｎｍ；ジクロロエタン）； Benzopyrylium cyanine dyes, for example the following formula:

8-[(6,7-dihydro-2,4-diphenyl-5H-1-benzopyran-8-yl) methylene] 5,6,7,8-tetrahydro-2,4-diphenyl-1- Benzopyrylium perchlorate (840 nm; dichloroethane);

で表される５−クロロ−２−[２−[３−[２−(５−クロロ−３−エチル−２(３Ｈ)−ベンゾチアゾリリデン)エチリデン]−２−ジフェニルアミノ−１−シクロペンテン−１−イル]エテニル]−３−エチルベンゾチアゾリウムパークロレート（８２５ｎｍ；ＤＭＳＯ）、
以下の式： Benzothiazole cyanine dyes, for example the following formula:

5-chloro-2- [2- [3- [2- (5-chloro-3-ethyl-2 (3H) -benzothiazolylidene) ethylidene] -2-diphenylamino-1-cyclopentene- 1-yl] ethenyl] -3-ethylbenzothiazolium perchlorate (825 nm; DMSO),
The following formula:

で表される３−エチル−２−[２−[３−[２−(３−エチル−２(３Ｈ)−ベンゾチアゾリリデン)エチリデン]−２−ジフェニルアミノ−１−シクロペンテン−１−イル]エテニル]ベンゾチアゾリウムパークロレート（８３１ｎｍ；ＤＭＳＯ）；

Represented by the formula: 3-ethyl-2- [2- [3- [2- (3-ethyl-2 (3H) -benzothiazolylidene) ethylidene] -2-diphenylamino-1-cyclopenten-1-yl] Ethenyl] benzothiazolium perchlorate (831 nm; DMSO);

で表される２−[２−[２−クロロ−３−[(３−エチル−１，３−ジヒドロ−１，１−ジメチル−２Ｈ−ベンズ[ｅ]インドール−２−イリデン)エチリデン]−１−シクロヘキセン−１−イル]エテニル]−１，１−ジメチル−３−エチル−１Ｈ−ベンズ[ｅ]インドリウムテトラフルオロボレート（８１６ｎｍ；ＭｅＯＨ）、以下の式： Indole cyanine dyes, for example the following formula:

2- [2- [2-Chloro-3-[(3-ethyl-1,3-dihydro-1,1-dimethyl-2H-benz [e] indole-2-ylidene) ethylidene] -1 -Cyclohexen-1-yl] ethenyl] -1,1-dimethyl-3-ethyl-1H-benz [e] indolium tetrafluoroborate (816 nm; MeOH), the following formula:

で表される３−ブチル−１，１−ジメチル−２−[２[２−ジフェニルアミノ−３−[(３−ブチル−１，３−ジヒドロ−１，１−ジメチル−２Ｈ−ベンズ[ｅ]インドール−２−イリデン)エチリデン]−１−シクロペンテン−１−イル]エチエニル]−１Ｈ−ベンズ[ｅ]インドリウムパークロレート（８３０ｎｍ；ＭｅＯＨ）、以下の式：

3-butyl-1,1-dimethyl-2- [2 [2-diphenylamino-3-[(3-butyl-1,3-dihydro-1,1-dimethyl-2H-benz [e] Indole-2-ylidene) ethylidene] -1-cyclopenten-1-yl] ethenyl] -1H-benz [e] indolium perchlorate (830 nm; MeOH), the following formula:

で表される２[２−[２−クロロ−３−[(３−エチル−１，３−ジヒドロ−１，１−ジメチル−２Ｈ−ベンズ[ｅ]インドール−２−イリデン)エチリデン]−１−シクロペンテン−１−イル]エテニル]−１，１−ジメチル−３−エチル−１Ｈ−ベンズ[ｅ]インドリウムアイオダイド（８４１ｎｍ；ＭｅＯＨ）；

2 [2- [2-Chloro-3-[(3-ethyl-1,3-dihydro-1,1-dimethyl-2H-benz [e] indole-2-ylidene) ethylidene] -1- Cyclopenten-1-yl] ethenyl] -1,1-dimethyl-3-ethyl-1H-benz [e] indolinium iodide (841 nm; MeOH);

で表される１，１，５，５−テトラキス[４−(ジエチルアミノ)フェニル]−１，４−ペンタジエン−３−イリウム＝ｐ−トリエンスルホナート（８１７ｎｍ；ＡｃＣＮ アセトニトリル）、以下の式： Polymethylene dyes such as the following formula:

1,1,5,5-tetrakis [4- (diethylamino) phenyl] -1,4-pentadiene-3-ylium = p-trienesulfonate (817 nm; AcCN acetonitrile), the following formula:

で表される１，５−ビス[４−(ジエチルアミノ)フェニル]−１，５−ビス(４−メトキシフェニル)−１，４−ペンタジエン−３−イリウムトリフルオロメタンスルホネート（８１９ｎｍ；ＡｃＣＮ）、以下の式：

1,5-bis [4- (diethylamino) phenyl] -1,5-bis (4-methoxyphenyl) -1,4-pentadiene-3-ylium trifluoromethanesulfonate (819 nm; AcCN) represented by formula:

で表される１，１，５，５−テトラキス[４−(ジエチルアミノ)フェニル]−１，４−ペンタジエン−３−イリウム＝ブチル(トリフェニル)ボレート（８２０ｎｍ；ＡｃＣＮ）

1,1,5,5-tetrakis [4- (diethylamino) phenyl] -1,4-pentadiene-3-ylium = butyl (triphenyl) borate (820 nm; AcCN)

  The compounding amount of the near-infrared absorbing dye in the photosensitive layer is such that the compound having the unsaturated double bond group and the urethane bond group, the alkali-soluble resin, and the ethylenically unsaturated polymerizable compound used as necessary. It is 0.05-20 mass parts with respect to 100 mass parts of total amounts, Preferably it is 0.5-10 mass parts. When the blending amount of the near-infrared absorbing dye is less than 0.05 parts by mass, curing becomes insufficient, and when it exceeds 20 parts by mass, curing of the lower layer becomes difficult.

［式中、Ｒ^１３、Ｒ^１４およびＲ^１５は、Ｒ^１３〜Ｒ^１５の少なくとも１つはトリクロロメチル基であるという条件で、独立してトリクロロメチル基、炭素数１〜１０、好ましくは１〜４の置換基を有していてもよいアルキル基、炭素数６〜１５、好ましくは６〜１０のアリール基、炭素数７〜２５、好ましくは７〜１４のアラルキル基、炭素数１〜１０、好ましくは１〜４のアルコキシ基、炭素数２〜１５、好ましくは２〜１０のアルケニル基、ピペリジノ基、ピペロニル基、アミノ基、炭素数２〜２０、好ましくは２〜８のジアルキルアミノ基、チオール基または炭素数１〜１０、好ましくは１〜４のアルキルチオ基である。］
で示されるような、少なくとも１つのトリクロロメチル基がＳ−トリアジン骨格の炭素原子に結合しているＳ−トリアジン化合物、およびトリブロモメチルスルホニル基を有する化合物、例えばトリブロモメチルフェニルスルホン、２−トリブロモメチルスルホニルピリジン、２−トリブロモメチルスルホニルベンズチアゾール等が挙げられる。 Halomethyl group-containing compound The halomethyl group-containing compound that can be contained in the photosensitive layer is an S-triazine compound having at least one methyl group in which at least one hydrogen atom is substituted with a chlorine atom or a bromine atom, preferably the following formula:

[Wherein, R ¹³ , R ¹⁴ and R ¹⁵ are independently a trichloromethyl group, having 1 to 10 carbon atoms, preferably 1 to ¹³ , provided that at least one of R ^{13 to} R ¹⁵ is a trichloromethyl group. An alkyl group which may have 4 substituents, an aryl group having 6 to 15 carbon atoms, preferably 6 to 10 carbon atoms, an aralkyl group having 7 to 25 carbon atoms, preferably 7 to 14 carbon atoms, 1 to 10 carbon atoms, Preferably 1-4 alkoxy groups, 2-15 carbon atoms, preferably 2-10 alkenyl groups, piperidino groups, piperonyl groups, amino groups, 2-20 carbon atoms, preferably 2-8 dialkylamino groups, thiols Or an alkylthio group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms. ]
An S-triazine compound in which at least one trichloromethyl group is bonded to a carbon atom of the S-triazine skeleton, and a compound having a tribromomethylsulfonyl group, such as tribromomethylphenylsulfone, Examples thereof include bromomethylsulfonylpyridine and 2-tribromomethylsulfonylbenzthiazole.

  Specific examples of S-triazine compounds that can be used particularly preferably include 2,4,6-tris (trichloromethyl) -S-triazine, 2-methyl-4,6-bis (trichloromethyl) -S-triazine. 2-methoxy-4,6-bis (trichloromethyl) -S-triazine, 2-phenyl-4,6-bis (trichloromethyl) -S-triazine, 2- (p-methoxyphenyl) -4,6- Bis (trichloromethyl) -S-triazine, 2- (4-methylthiophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (p-chlorophenyl) -4,6-bis (trichloromethyl) -S-triazine, 2- (4-methoxynaphthyl) -4,6-bis (trichloromethyl) -S-triazine, 2-piperonyl-4,6-bis (trichloromethyl) -S-triazine, 2-pi Lydino-4,6-bis (trichloromethyl) -S-triazine, 2-styryl-4,6-bis (trichloromethyl) -S-triazine, 2- (p-methoxystyryl) -4,6-bis (trichloro Methyl) -S-triazine, 2- (3,4-dimethoxystyryl) -4,6-bis (trichloromethyl) -S-triazine, 2- (p-dimethylaminostyryl) -4,6-bis (trichloromethyl) ) -S-triazine.

  The compounding amount of the halomethyl group-containing compound in the photosensitive layer is 0.1 to 20 parts by mass with respect to 100 parts by mass of the total amount of the compound having the unsaturated double bond group and the urethane bond group and the alkali-soluble resin. The amount is preferably 1 to 10 parts by mass. If the amount of the halomethyl group-containing compound is less than 0.1 parts by mass, curing is insufficient, and if it exceeds 20 parts by mass, the solvent resistance of the cured product may be reduced.

［式中、Ｒ^１、Ｒ^２、Ｒ^３およびＲ^４は、独立して炭素数１〜１０のアルキル基、炭素数６〜１５のアリール基、炭素数２〜１０のアルカノール基、アリル基、炭素数１〜１０のアラルキル基、炭素数１〜１０のアルケニル基または炭素数１〜１０のアルキニル基であり、これらの基は置換基を有していてよく、Ｘ^＋は対カチオン、アルカリ金属カチオン（例えば、ナトリウムカチオン、リチウムカチオン）またはホスホニウムカチオンである。］ Organoboron anion-containing compound The photosensitive layer constituting the negative photosensitive lithographic printing plate may contain an organoboron anion-containing compound. Examples of the organic boron anion-containing compound that can be contained in the optical layer include the following compounds.

[Wherein R ¹ , R ² , R ³ and R ⁴ are each independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, an alkanol group having 2 to 10 carbon atoms, an allyl group, An aralkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, or an alkynyl group having 1 to 10 carbon atoms, and these groups may have a substituent, and X ⁺ is a counter cation or an alkali metal. Cation (for example, sodium cation, lithium cation) or phosphonium cation. ]

  Examples of the organic boron anion-containing compound represented by the above formula include sodium tetraphenyl borate, lithium triphenyl n-butyl borate, tetraphenylphosphonium tetrakis (4-methylphenyl) borate, tetraphenylphosphonium tetraphenylborate, benzyltriphenyl Examples thereof include phosphonium tetraphenylborate and 4-methylphenyltriphenylphosphonium tetrakis (4-methylphenyl) borate.

［式中、Ｒ^５、Ｒ^６、Ｒ^７およびＲ^８は独立して炭素数１〜１０のアルキル基、炭素数６〜１５のアリール基、炭素数２〜１０のアルカリール基、アリル基、炭素数１〜１０のアラルキル基、炭素数１〜１０のアルケニル基、炭素数１〜１０のアルキニル基、シリル基、脂環式基または複素環基であり、これらの基は置換基を有していてもよく、また環状構造を有してもよく、Ｒ^９、Ｒ^１０、Ｒ^１１およびＲ^１２は、独立して炭素数１〜１０のアルキル基、炭素数６〜１５のアリール基、炭素数２〜１０のアルカリール基、アリル基、炭素数１〜１０のアラルキル基、炭素数１〜１０のアルケニル基または炭素数１〜１０のアルキニル基であり、これらの基は置換基を有していてもよい（但し、Ｒ^９、Ｒ^１０、Ｒ^１１およびＲ^１２の少なくとも一つがアルキル基であるのが好ましい）。］ Moreover, as an example of an organic boron anion containing compound, the following compound can also be used, for example.

[Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, an alkaryl group having 2 to 10 carbon atoms, an allyl group, An aralkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, an alkynyl group having 1 to 10 carbon atoms, a silyl group, an alicyclic group, or a heterocyclic group, and these groups have a substituent. R ⁹ , R ¹⁰ , R ¹¹ and R ¹² may be independently an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, carbon, An alkaryl group having 2 to 10 carbon atoms, an allyl group, an aralkyl group having 1 to 10 carbon atoms, an alkenyl group having 1 to 10 carbon atoms, or an alkynyl group having 1 to 10 carbon atoms, and these groups have a substituent. which may be ^{(but, R 9, R 10, R} 11 and ^{R 1} At least one of preferably a alkyl group) in. ]

  Examples of the organic boron anion-containing compound represented by the above formula include tetramethylammonium tetraphenylborate, tetraethylammonium tetraphenylborate, tetramethylammonium tetraanisylborate, 1,5-diazabicyclo [4.3.0] nonene- 5-tetraphenylborate, 1,8-diazabicyclo [5.4.0] undecene-7-tetraphenylborate, 2-ethyl-4-methylimidazolium tetraphenylborate, tetramethylammonium triphenyl n-butylborate, tetra Methylammonium triphenyl n-octylborate, tetraethylammonium triphenyl n-butylborate, tetramethylammonium trianisyl n-butylborate and tetraethylammonium diphenyl Examples include di n-butyl borate.

  The compounding amount of the organoboron anion-containing compound in the photosensitive layer is such that the compound having the unsaturated double bond group and the urethane bond group, the alkali-soluble resin, and the ethylenically unsaturated polymerizable compound used as necessary. It is 0.1-20 mass parts with respect to 100 mass parts of total amounts, Preferably it is 1-10 mass parts. If the compounding amount of the organic boron anion-containing compound is less than 0.1 parts by mass, curing becomes insufficient, and if it exceeds 20 parts by mass, the solvent resistance of the cured product may be reduced.

The nitroxyl compound photosensitive layer may contain a nitroxyl compound as yet another component. The nitroxyl compound can improve the storage stability (particularly the light room stability) of a photosensitive layer, particularly a printing plate material for CTP (computer-to-plate) having photosensitivity at 830 nm.

  As the nitroxyl compound, known compounds described in JP-A-10-97059 can be used. Specific examples of the nitroxyl compound include di-tert-butylnitroxyl, 1-oxyl-2,2,6,6-tetramethylpiperidine, 1-oxyl-2,2,6,6-tetramethylpiperidino. -4-ol, 1-oxyl-2,2,6,6-tetramethylpiperidino-4-one, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1 -Oxyl-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1 -Oxyl-2,2,6,6-tetramethylpiperidin-4-ylbenzoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-4-tert-butylbenzoate, bis ( 1-Oki Sil-2,2,6,6-tetramethylpiperidin-4-yl) succinate, bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate, bis (1- Oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) n-butyl malonate, Bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) phthalate, bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) isophthalate Bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) terephthalate, bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) hexa Hydroterephthalate, N, N ' Bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipamide, N- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) caprolactam N- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) dodecylsuccinimide, 2,4,6-tris (1-oxyl-2,2,6,6-tetramethyl Piperidin-4-yl) isocyanurate, 2,4,6-tris [N-butyl-N- (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)] s-triazine Or 4,4′-ethylenebis (1-oxyl-2,2,6,6-tetramethylpiperazin-3-one). Most preferred is bis (1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate.

  The compounding amount of the nitroxyl compound in the composition is 100 in total of the compound having the unsaturated double bond group and the urethane bond group, the alkali-soluble resin, and the ethylenically unsaturated polymerizable compound used as necessary. It is 0.1-1 mass part with respect to a mass part, Preferably it is 0.1-0.5 mass part, More preferably, it is 0.1-0.3 mass part. When the amount is less than 0.1 parts by mass, the effect of improving the storage stability due to the addition of the nitroxyl compound is not exhibited. If the amount is more than 1 part by mass, it may be difficult to cure the photosensitive layer.

Other additives For photosensitive layers that can be developed with alkali, as other additives, solvents, colorants, matting agents, fillers, thermal polymerization inhibitors, plasticizers, surfactants for improving coating properties, antifoaming An agent and inorganic or organic fine filler may be contained. As the inorganic filler, fine powder silica (particle size 0.001 to 2 μm) and colloidal silica (particle size 0.001 to 1 μm) dispersed in a solvent are preferable. As the organic filler, a microgel having a gelled inside (particle size: 0.01 to 5 μm) is preferable. Particularly preferred microgels include known microgels disclosed in JP-A-4-274428. This is a microgel having a particle size of 0.01 to 2 μm adjusted by emulsion polymerization using a polymer emulsifier having an Sp value of 9 to 16.

  Compounds having an unsaturated double bond group and a urethane bond group as described above, alkali-soluble resins, near-infrared absorbing dyes, and ethylenically unsaturated polymerizable compounds, halomethyl group-containing compounds, and organic boron used as necessary To prepare a photosensitive layer by adding an anion-containing compound and, if necessary, other additives to a solvent, and mechanically stirring and mixing using a device well known to those skilled in the art, such as a high-speed stirrer, in the dark. The photosensitive resin composition can be obtained.

Protective layer
Water-soluble or alkali-soluble resin The negative photosensitive lithographic printing plate used in the present invention may have a protective layer on the photosensitive layer. The protective layer is formed on the photosensitive layer. The protective layer needs to be formed from a water-soluble or alkali-soluble resin. Furthermore, a photopolymerizable photosensitive layer using a radical chain polymerization reaction is particularly effective for increasing the sensitivity of the photosensitive layer for a negative photosensitive lithographic printing plate, but it is affected by oxygen in the air. Since chain polymerization stops at an initial stage or in the middle, it is necessary to further provide an oxygen blocking layer on the surface of the photosensitive layer. Therefore, the protective layer preferably has an oxygen barrier property.

  Examples of water-soluble or alkali-soluble resins that can be used in the protective layer include, but are not limited to, (i) partially saponified products of polyvinyl alcohols such as polyvinyl acetate (degree of saponification: 70 to 99 mol%) , Partially saponified product of maleic acid modified polyvinyl acetate, partially saponified product of itaconic acid modified polyvinyl acetate, partially saponified product of ethylene modified polyvinyl acetate, Kuraray Co., Ltd. trade name “EXVAL” (RS-4104, RS-4105) , RS-3110, RS-2117, RS-1117, RS-2817, RS-1717, RS-1113, RS-2713, RS-1713 and other water-soluble resins known as (ii) gelatin; iii) gum arabic; (iv) polyethylene oxides; (v) polypropylene oxides; (vi) Rivinyl pyrrolidones such as polyvinyl pyrrolidone, copolymers of vinyl pyrrolidone and vinyl acetate, alkylated polyvinyl pyrrolidones; (vii) copolymers of methyl vinyl ether and maleic anhydride; (viii) celluloses such as hydroxyethyl cellulose; Hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose; (ix) unsaturated carboxylic acid (eg, acrylic acid, methacrylic acid, itaconic acid, etc.) and ethylenically unsaturated compound (eg, styrene, α-methylstyrene, acrylonitrile, acrylic) Acid ester and the like), for example, a copolymer of styrene, α-methylstyrene, and acrylic acid; and mixtures thereof. Polyvinyl alcohols, polyvinyl pyrrolidones, copolymers of methyl vinyl ether and maleic anhydride, and copolymers of unsaturated carboxylic acids and ethylenically unsaturated compounds are preferred. A protective layer is formed on the photosensitive layer by applying and drying the water-soluble or alkali-soluble resin, (i) to (viii) from an aqueous solution, and (ix) from an aqueous ammonia solution, through a coating and drying process.

A negative photosensitive lithographic printing plate obtained by combining an organic pigment and / or water-soluble dye photosensitive layer and a protective layer is used to improve the working environment in the image exposure process. The water-soluble or alkali-soluble resin for the protective layer is an organic pigment having absorption in a wavelength region of 400 to 800 nm, so that it can be handled from the viewpoint of quality deterioration when exposed under bright safety light. It is desirable to further contain a water-soluble dye. Specifically, the absorption wavelength and absorbance of the protective layer may be adjusted so as to sufficiently shield the emission wavelength (400 to 700 nm) of a white fluorescent lamp cut with ultraviolet rays or the emission wavelength (500 to 700 nm) of a yellow lamp. . The absorbance is preferably 2.0 or higher (99% or higher shielded).

  In the case where a nitroxyl compound is contained in the photosensitive layer, the protective layer itself does not necessarily have an organic pigment and / or a water-soluble dye because the photosensitive layer itself has bright room stability. In the following description, the case where an organic pigment and / or a water-soluble dye is included will be mainly described.

  The organic pigment is an insoluble organic pigment having light absorption at 400 to 800 nm, and any conventionally known pigment may be used. In particular, insoluble azo-based azo lakes such as monoazo, disdaazo, and metal complexes , Phthalocyanine, anthraquinone, thioindigo, perylene, perinone, quinacridone, isoindolinone, dioxazine, quinophthalone, and diketopyrrolopyrrole organic pigments. The water-soluble dye is preferably an anionic dye having a sulfonate structure. Two or more of these may be used in combination to obtain the desired light absorption.

  Examples of the organic pigment used in the protective layer include C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 12, C.I. I. Pigment Red 22, C.I. I. Pigment Red 254, C.I. I. Pigment Violet 1, C.I. I. Pigment Violet 23, C.I. I. Pigment Blue 1, C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 4 and the like. In particular, azo dyes and phthalocyanine dyes are preferable.

  Cationic dyes are said to absorb light and excite and react with organoboron anion-containing compounds to produce radical species. When the dye migrates to the photosensitive layer, the photosensitive layer is used when the oxygen concentration is low. When the oxygen concentration is high, the polymer is trapped by oxygen, the effective concentration of the organic boron anion-containing compound is lowered, the sensitivity is lowered, and an image is not formed. Therefore, since the photosensitive layer contains an organic boron anion-containing compound, when a dye is used, a cationic dye such as a basic dye cannot be used, and an anionic dye having a sulfonate structure is desirable. The further advantage of using the anionic dye having the sulfonate structure is that the water solubility of the dye is very good, so that it can be easily mixed with the aqueous solution of the water-soluble or alkali-soluble resin, and alcohol. Therefore, the transfer to a photosensitive layer containing a compound having an unsaturated double bond group and a urethane bond group is extremely small.

  Examples of the anionic dye having the sulfonate structure used in the protective layer include C.I. I. Acid Yellow 1, C.I. I. Acid Yellow 23, C.I. I. Acid Red 26, C.I. I. Acid Red 35, C.I. I. Acid Blue 1, C.I. I. Acid Blue 9, C.I. I. Direct Yellow 4, C.I. I. Direct Yellow 12, C.I. I. Direct Red 28, C.I. I. Direct Red 39, C.I. I. Direct Blue 6, C.I. I. Direct Blue 22, C.I. I. Modern Blue 13, C.I. I. For example, Modern Blue 56.

  The amount of the organic pigment and the water-soluble dye is 25 to 50 parts by mass, preferably 30 to 45 parts by mass, more preferably 30 to 35 parts per 100 parts by mass of the water-soluble or alkali-soluble resin for the protective layer. Part by mass. When the blending amount is less than 25 parts by mass, the shielding property against bright safety light such as white light or yellow light cut by ultraviolet rays is insufficient, and therefore the photosensitive layer may be cured when exposed to such safety light for a long time. . On the other hand, if it exceeds 50 parts by mass, the oxygen barrier property of the protective layer will be adversely affected, so that an image may not be formed.

  Compared to the water-soluble dye, the organic pigment has advantages in that the finger does not get dirty even when the surface of the printing plate is touched with a wet finger, or there is no migration to the photosensitive layer. Therefore, there is a disadvantage that it cannot be easily mixed with the aqueous solution of the water-soluble or alkali-soluble resin. Accordingly, when the organic pigment is used, it is preferably used as a pigment dispersion in which the organic pigment is uniformly dispersed in an aqueous medium in advance. However, when the aqueous solution of the water-soluble or alkali-soluble resin and the pigment dispersion are mixed, there may be a problem that the organic pigment that is well dispersed causes a shock and aggregates. In addition, in order to exhibit a sufficient shielding effect against bright safety light such as a white light or a yellow light cut by ultraviolet rays, it is necessary to increase the pigment concentration. In such a case, a viscosity suitable for the coating apparatus can be obtained. In some cases, the pigment particles may aggregate during storage or the viscosity of the pigment dispersion may increase or gelation may occur.

In order to solve the above problem, when an organic pigment is used in the protective layer, it is preferable to further contain a water-soluble or water-dispersible resin containing an ionic group, and a polymer having an ionic group as an optional component. It is more preferable to contain other additives such as a dispersant or a surfactant. That is, as one aspect of the protective layer,
In addition to (i) a water-soluble or alkali-soluble resin, and (ii) an organic pigment,
(Iii) water-soluble or water-dispersible resins containing ionic groups, and (iv) those containing other additives as required.

The compounding amount of the above components (i) to (iv) is based on 100 parts by mass of the water-soluble or alkali-soluble resin (i).
Organic pigment (ii) 25-50 parts by mass, preferably 30-45 parts by mass, water-soluble or water-dispersible resin (iii) containing an ionic group (iii) 5-15 parts by mass, preferably 5-10 parts by mass, etc. The additive (iv) is 0.1 to 5 parts by mass, preferably 0.1 to 3 parts by mass.

  If the water-soluble or water-dispersible resin (iii) containing the ionic group is less than 5 parts by mass, the dispersibility of the pigment is deteriorated, and if it exceeds 15 parts by mass, the oxygen barrier property of the protective layer is adversely affected. If the other additive (iv) is less than 0.1 part by mass, the formed protective layer may not be a uniform film, and if it exceeds 5 parts by mass, the function as the protective layer is adversely affected.

  As the organic pigment (ii), those described above are effectively used. Two or more of these may be used in combination to obtain the desired light absorption.

  As the water-soluble or water-dispersible resin (iii) containing the ionic group, an acidic group (for example, carboxyl group, sulfone group, phosphoric acid group) or a basic group (for example, amino group, It is selected from acrylic resins containing an imino group), epoxy resins, polybutadiene resins, and polyester resins. A resin having an acidic group as an ionic group is usually water-soluble or water-dispersed (so-called anionic resin) by neutralization with a base such as ammonia, organic amine, potassium hydroxide or the like. In addition, resins having basic groups such as amino groups as ionic groups are usually inorganic acids such as hydrochloric acid and nitric acid or organic acids such as phosphoric acid, formic acid, acetic acid, hydroxyacetic acid, sulfamic acid, and lactic acid. It is added to be water-soluble or water-dispersed (so-called cationic resin).

  Among these, an unsaturated monomer having an acidic group, and, if necessary, 0 to 60% by mass of an unsaturated monomer having a hydroxyl group, and an acrylic anion resin obtained by copolymerizing another unsaturated monomer, preferable. The acidic group is particularly preferably a carboxyl group. Examples of the unsaturated monomer having an acidic group include (meth) acrylic acid, itaconic acid, maleic acid, maleic anhydride and the like, or derivatives thereof. The resin having an acidic group may be a copolymer of the above monomer, an unsaturated monomer having a hydroxyl group, and other unsaturated monomers as necessary. As unsaturated monomers having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, lactone-modified hydroxyethyl (meth) acrylate, polyethylene glycol (meth) Examples include acrylate, polypropylene glycol (meth) acrylate, and derivatives thereof. Other unsaturated monomers include styrene, methyl (meth) acrylate, cyclohexyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, vinyl acetate, acrylonitrile, etc. It may be a known monomer.

  As the water-soluble or water-dispersible resin (iii) containing the organic pigment (ii) and the ionic group, a dispersion obtained by previously dispersing (ii) in (iii) may be used. Examples of these include, for example, “Himicron K Blue 2453”, “Himicron K Green 13983”, “Himicron K Violet 2419”, “Himicron (manufactured by Gokoku Coloring Co., Ltd.). Himicron K Red 10159 ”,“ Himicron K Red 12266 ”and the like.

  Examples of other additives (iv) include polymer dispersants or surfactants having an ionic group, which are added as necessary. The content of the insoluble organic pigment may be an amount sufficient to have the desired light absorption. However, if the amount is too large, the water dispersibility deteriorates, so that the amount of organic pigment necessary to have the desired light absorption. The pigment is preferably used after a pigment dispersion is prepared by dispersing and mixing the pigment in the resin (iii) in advance by adding a polymer dispersing agent or surfactant having an ionic group. In this case, the ionicity (that is, anionic or cationic) of the resin (iii) and the ionicity of the polymer dispersant for dispersing the organic pigment are the same, but the ionic species, that is, the functional group species are not necessarily limited. It does not have to be the same.

  The method for producing the aqueous dispersion of the organic pigment is not particularly limited as long as it is a method generally used as a method for dispersing the pigment. Specifically, an organic pigment, a water-soluble or water-dispersible resin containing an ionic group, and if necessary, a polymer dispersant or a surfactant having an ionic group are mixed in water, glass beads, Add a medium such as zirconia beads, and disperse with a paint conditioner, ball mill, sand grinder or the like. Moreover, it can also disperse | distribute using a kneader, 2 rolls, 3 rolls, a homogenizer system, a jet mill, an ultrasonic wave. Moreover, you may combine these dispersion methods.

  The average particle size of the pigment in the dispersion is 40 to 500 nm, preferably 60 to 200 nm. The viscosity of the dispersion is 2 to 10 mPa · s, preferably 3 to 5 mPa · s. (Measuring device for particle size distribution: Microtrac UPA manufactured by Honeywell, conditions: 20 ° C., viscometer: E-type viscometer, conditions: 25 ° C., 50 rpm). When the average particle size is larger than 500 nm, coarse particles of 1 micron or more exist, and there is a problem that clogging occurs in the filter process. When the average particle size is less than 40 nm, there may be problems such as an increase in the viscosity of the dispersion, poor stability, and poor coating properties.

In an apparatus that automatically supplies a matting agent printing plate material, a plate is drawn using a suction cup from a stack of multiple plate materials (usually about 500 sheets) stacked without interleaving between the plate material and the plate material. When conveying the materials one by one, there is a problem that a plurality of sheets are lifted at a time due to the close contact between the plate materials. In order to solve such a problem, the photosensitive layer or the protective layer formed on the photosensitive layer or the like by containing resin particles in the protective layer or the like formed on the photosensitive layer or using a gravure roll or the like. It has been proposed that irregularities be formed on the surface (Japanese Patent Laid-Open No. 2000-235255, Japanese Patent Laid-Open No. 51-96604, Japanese Patent Laid-Open No. 55-12974, Japanese Patent Laid-Open No. 58-182636, etc.) .

  In order to solve the above-described problem of lifting a plurality of sheets at a time, the protective layer preferably contains a matting agent. The matting agent used in the protective layer desirably has an average particle size of 3 to 20 μm, preferably 5 to 15 μm, more preferably 6 to 12 μm. When the average particle size of the matting agent is less than 3 μm, it often happens that a plurality of sheets are lifted up. When the average particle size is greater than 12 μm, the bundle plates slip and do not overlap well, and the laser is irregularly reflected to produce a clear image. Cannot be obtained. The matting agent preferably has a particle size distribution of 1 to 30 μm, preferably 1 to 25 μm, more preferably 1 to 20 μm.

  Examples of the matting agent used in the protective layer include, but are not limited to, silica particles as representative examples of inorganic materials, and crosslinked resin particles such as crosslinked polymethyl methacrylate and crosslinked polystyrene as typical examples of organic materials. . In the case of the organic material, crosslinked resin particles are preferable because the particles collapse when the plate material is stacked unless crosslinked.

  The blending amount of the matting agent is 0.05 to 0.5% by mass, preferably 0.1 to 0.45% by mass, more preferably 0.15 to 5% by mass with respect to the solid content of the protective layer composition. It is desirable that it is 0.4 mass%. When the blending amount of the matting agent is less than 0.05% by mass, it often happens that a plurality of sheets are lifted at the same time as described above. When the amount exceeds 0.5% by mass, a plate material is obtained when a plurality of plate materials are stacked. As a result, the laser beam cannot be stacked well, and the laser is irregularly reflected, so that a clear image is not formed.

  The protective layer may also contain, as additives, a fine filler such as colloidal silica, a surfactant for improving coating properties, and an antifoaming agent.

Production method of negative photosensitive lithographic printing plate Production method of negative photosensitive lithographic printing plate
Forming a photosensitive layer on the aluminum support, and forming a protective layer on the resulting photosensitive layer.

The matting agent described above may be contained in the photosensitive layer or in the protective layer.
A step of forming a layer containing a matting agent on the protective layer may be further provided so as to be contained in the negative photosensitive lithographic printing plate. In the above process, the method for forming the layer containing the matting agent is not particularly limited, and the layer is formed by spraying an appropriate binder resin and matting agent using an organic solvent and then drying. In a printing plate material automatic supply device, when a plate material is transported one by one using a suction cup from a stack of plate materials stacked without interleaving between the plate material and the plate material, The matting agent is preferably contained in the protective layer because it is effective against the problem of lifting a plurality of sheets at once due to the close contact between the materials, and there is no inconvenience such as an increase in the number of steps.

In the step (a), the method for coating the photosensitive layer on the support is not particularly limited. For example, natural coater, reverse coater, gravure coater, curtain coater, air spray, airless spray, bar coater, knife coater, It is applied using a spin coater or the like, and then dried at 40 to 80 ° C. for 1 to 10 minutes, for example. The coating amount after drying is preferably about 0.5 to 2.5 g / m ² .

The method for coating the protective layer on the photosensitive layer is not particularly limited. For example, coating using a natural coater, reverse coater, gravure coater, curtain coater, air spray, airless spray, bar coater, knife coater, spin coater, etc. Then, for example, it is dried at 60 to 100 ° C. for 1 to 10 minutes. The coating amount after drying is preferably about 1.0 to 2.5 g / m ² .

Plate making method of planographic printing plate
An exposure process for exposing a negative photosensitive lithographic printing plate using a near-infrared laser;
Developing the exposed negative photosensitive lithographic printing plate using the alkaline developer for photosensitive lithographic printing,
It is a method including.

  More specifically, the near infrared laser is preferably a semiconductor laser having a wavelength near 830 nm. Moreover, you may wash a protective layer with water after the said exposure process and before a image development process as needed. Moreover, after a development process, you may process with a desensitizing agent and then heat-process as needed. An improvement in soil resistance can also be expected by the desensitizing treatment.

  The desensitizing agent is not particularly limited as long as it is usually used for such applications. Generally, it is sold under names such as “finishing gum” and “plate surface protection solution”, but it is diluted with water, and then the plate surface is rubbed with a sponge and dried, or an automatic coating device is used. The plate surface may be processed by a method such as coating and drying.

  The heat treatment conditions that can be performed as necessary after the desensitizing treatment are preferably performed at 80 to 150 ° C. for 0.1 to 5 minutes.

  The following examples further illustrate the present invention, but the present invention is not limited thereto. In the examples, “parts” and “%” are based on mass unless otherwise specified.

Production Examples 1 to 3 Production of negative photosensitive lithographic printing plates (printing plates 1 to 3)
Formation of photosensitive layer An aluminum support (silicate treatment) obtained by anodizing an organic solvent solution (organic solvent: methoxypropanol, 8%) of a photosensitive resin composition containing the components shown in Table 1 below using a bar coater. And dried at 80 ° C. for 5 minutes to form a photosensitive layer having a coating amount of 1.2 g / m ² . In addition, the numerical value in the following table means a solid content mass part.

（注１）ダイセル化学工業（株）の商品（商品名：サイクロマーＰ）、側鎖にアクリル基とカルボキシル基とを含有するアクリル共重合樹脂
（注２）下記式で示される、不飽和二重結合基およびウレタン結合基を有する化合物：

(Note 1) Products of Daicel Chemical Industries, Ltd. (trade name: Cyclomer P), acrylic copolymer resin containing an acrylic group and a carboxyl group in the side chain (Note 2) Compound having a heavy bond group and a urethane bond group:

（注３）１，１，５，５−テトラキス[４−(ジエチルアミノ)フェニル]−１，４−ペンタジエン−３−イリウム−ｐ−トルエンスルホネート
（注４）テトラｎ−ブチルアンモニウムトリフェニルｎ−ブチルボレート
（注５）２，４，６−トリス(トリクロロメチル)−Ｓ−トリアジン
（注６）２’−(２−ブロモ−４−ニトロ−６−シアノフェニルアゾ)−５’−ジエチルアミノプロピオアニリド；三井化学社製ＥＸ−２３６

(Note 3) 1,1,5,5-tetrakis [4- (diethylamino) phenyl] -1,4-pentadiene-3-ylium-p-toluenesulfonate (Note 4) tetra n-butylammonium triphenyl n-butyl Borate (Note 5) 2,4,6-Tris (trichloromethyl) -S-triazine (Note 6) 2 '-(2-bromo-4-nitro-6-cyanophenylazo) -5'-diethylaminopropioanilide ; EX-236 manufactured by Mitsui Chemicals, Inc.

Formation of protective layer On the photosensitive layer formed as described above, a 7% by weight aqueous solution of polyvinyl alcohol (Poval 205) was applied so as to give a coating amount of 1.5 g / m ² to form a protective layer.
Thus, printing plates 1 to 3 having a photosensitive layer and a protective layer were produced.

Examples 1 to 13 and Comparative Examples 1 to 13 Preparation of photosensitive lithographic printing alkali developer A photosensitive lithographic printing alkaline developer containing the components shown in Tables 2 to 5 below was prepared. In addition, the numerical value (except water) of each component in the following table means a solid content mass part.

(Note 7): Polypropylene glycol disulfonic acid sodium salt (Note 8): Alkylnaphthalenesulfonic acid sodium salt (Note 9): Polyoxyethylene aryl ether sulfonic acid sodium salt (Note 10): Acetylene glycol antifoaming agent (Note 11) ): Hydroxyethylethylenediaminetriacetic acid trisodium salt

Using the prepress printing plates 1 to 3 of the lithographic printing plate, a pattern of halftone dots 75, 50 and 25% was drawn and exposed at a strength of 6.5 W on a Trendsetter NEWS of Creo. A brush type automatic developing machine was filled with the alkaline developer for photosensitive lithographic printing of the above Example or Comparative Example and developed at 30 ° C. After washing with water, gumming was performed with a 1: 1 water-diluted product of PS finishing gum GN-2 manufactured by Fuji Photo Film Co., Ltd., and then air-dried to form an image on a lithographic printing plate.

  The image forming properties and printing performance of the lithographic printing plate obtained as described above were evaluated.

Evaluation of image formability (saturation | b | value measurement)
In the evaluation method of developability, the saturation, which is the color difference of the development plate surface, was evaluated by the | b | value, and the direction showing a smaller value was desirable. For the measurement of the | b | value, a colorimeter color reader CR-13 manufactured by Konica Minolta Sensing Co., Ltd. was used.
Evaluation criteria ◎ ・ ・ ・ | b |
○ ... | b | Although the value is <1.5, there is no problem in use.
Δ: 1.5 <| b | Value <2.0 is problematic and difficult to use.
× ... 2.0 <| b | value, which is difficult to use.

Evaluation of image formability (measurement of halftone reproducibility)
The halftone dot 75, 50, and 25% patterns of the obtained image were evaluated by measuring the halftone dot reproducibility using an X-RiteDot measuring machine manufactured by X-Rite Co., Ltd.
Evaluation criteria ◎ ... No problem at all within ± 0.5%.
○ ... No problem with runout within ± 1.0%.
Δ: Deflection within ± 1.5%, difficult to use.
X: The swing width is ± 2.0% or more and is difficult to use.

Evaluation of image formability (measurement of ink repellency test)
The developed and imaged plate material was tested for ink repellency by running the tap water for 30 seconds to remove the gum, drying at 60 ° C for 2 minutes, cooling, and applying newspaper ink (black) with a rubber roll at room temperature. Left for 30 minutes. Tap water was allowed to flow for 20 seconds to lift the ink, and then the ink was wiped off with a waste cloth (cotton cloth) while the water was continuously applied. After air-drying, the ink repellency was evaluated according to the following evaluation criteria by visual judgment of the degree of stain with ink.
Evaluation Criteria ◎ ・ ・ ・ No dirt and practical problems.
○: There is a slight darkening, but there is no problem in practical use.
Δ: Darkened and difficult to use.
X: Black and difficult to use.

Evaluation of insoluble matter in developer (Measurement of insoluble matter test)
40 mL of the alkali developer for photosensitive lithographic printing of the above Example or Comparative Example was placed in a stainless bat having a length of 30 cm, a width of 22 cm, and a height of 4.5 cm. Immerse 26 unirradiated printing plates of length 140cm and width 20cm one by one at room temperature, and use a rubber hand squeegee to dissolve the coating film into a 50mL glass screw bottle. The degree of precipitate generation was evaluated.
Evaluation criteria ◎ ・ ・ ・ No insoluble matter, no problem in practical use.
○: There is a slight precipitate, but when shaken, it is completely dispersed and dissolved, and there is no problem in practical use. Δ: There is a precipitate, and even if shaken, it is not completely dispersed and dissolved, making it difficult to use.
X: Precipitate is present, hard cake, does not disperse and dissolve, and is difficult to use.

  Tables 6 and 7 show the evaluation results of the image forming property and the insoluble matter generation test in the developer.

Evaluation of printing durability (measurement of the number of printed sheets)
The lithographic printing plate produced by the above method is a printing master printing machine manufactured by Heidenberg Co., Ltd., and the ink is printed using TK High Unity ink of Toyo Ink Manufacturing Co., Ltd. and a commercial fountain solution, The number of printed sheets when printing could not be continued either due to poor ink printing on the paper surface or when the plate surface image was worn was evaluated according to the following criteria.
Evaluation standard ○ ・ ・ ・ No problem in practical use with 100,000 sheets or more.
Δ: 50 to 90,000 sheets, which are difficult to use practically.
×: Less than 50,000 sheets, unusable for use.

  The results of printing durability performance are shown in Tables 8 and 9 below.

Evaluation of continuous developability (measurement of contamination of insoluble matter on the plate surface)
New developing solution per Developer 1 liter with brush-type automatic developing machine replenishment system for 40ml add, 1 m ² development and after 100 m ² non-image areas of the plate surface after development processing for each of developing the printing plate 1 m ² The degree of the presence or absence of adhesion stains due to the insoluble matter and the degree of stains on the paper surface when printed using this plate surface were evaluated.
Evaluation Criteria ◎ ・ ・ ・ No dirt is observed and there is no practical problem.
○: Slightly adhered matter is observed, but there is no problem in practical use.
Δ: Adherents are reliably recognized and difficult to use.
X: Dirt is so severe that it cannot be used.

  The results of continuous developability are shown in Tables 10 and 11 below.

As shown in the above evaluation results, the photosensitive lithographic printing alkali developers of the examples are negative photosensitive lithographic printing plates having an aluminum support that has not been subjected to a silicate treatment, and are not present in the photosensitive layer. It turns out that it is very suitable for image development of the printing plate (printing plates 1-3) containing 10-80 mass% of compounds which have a saturated double bond group and a urethane bond group.
On the other hand, it was confirmed that the photosensitive developer for photosensitive lithographic printing of Comparative Example was inferior in image formability, insoluble matter evaluation and printing durability performance even when developing the printing plates 1 to 3 described above. It was.

  By using the alkaline developer for photosensitive lithographic printing of the present invention, excellent printing performance and continuous developability can be obtained in lithographic printing plate making. The alkaline developer for photosensitive lithographic printing of the present invention is very suitable for developing a negative photosensitive lithographic printing plate having an aluminum support that has not been subjected to a silicate treatment.

Claims (6)

Benzyl alcohol (a) is 0.2 to 5% by mass based on the total mass of the developer,
Tetraalkylammonium hydroxide (b) in an amount of 0.2 to 1.5% by solid content based on the total mass of the developer, and a polyoxyalkylene non-aryl type anionic surfactant (c),
An alkaline developer for photosensitive lithographic printing, comprising:   2. The alkali development for photosensitive lithographic printing according to claim 1, wherein the content of the polyoxyalkylene non-aryl type anionic surfactant (c) is 0.5 to 15% by mass based on the total mass of the developer. liquid.   The alkaline developer for photosensitive lithographic printing according to claim 1 or 2, wherein the polyoxyalkylene non-aryl type anionic surfactant (c) is a polyoxyalkylene glycol disulfonate. Furthermore, the following formula

[Wherein R ¹ represents a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, HOCOCH ₂ —, HOCOCH ₂ CH ₂ —,
R ² is a hydrogen atom, an alkyl group having 1 to 7 carbon atoms, an aryl group having 7 to 12 carbon atoms, HOCOCH ₂ —, HOCOCH ₂ CH ₂ —, H ₂ NCOCH ₂ —, HSCH ₂ —, H ₂ NCOCH ₂ CH _{2 -, CH 3 SCH 2 CH} 2 -, HOCH 2 -, CH 3 CH (OH) -, HOC 6 H 4 CH 2 - or _{H 2 N (CH 2) 4} - indicates,
m shows the integer of 1-10. ]
The photosensitive lithographic printing according to any one of claims 1 to 3, wherein the aminocarboxylic acid or a salt thereof (d) represented by the formula (1) comprises 0.01 to 2% by mass of the solid content with respect to the total mass of the developer. Alkali developer.   The alkaline developer for photosensitive lithographic printing according to any one of claims 1 to 4, wherein the pH is 12 to 14. An exposure process for exposing a negative photosensitive lithographic printing plate using a near-infrared laser;
A developing step of developing the exposed negative photosensitive lithographic printing plate using the alkaline developer for photosensitive lithographic printing according to claim 1,
A process for making a lithographic printing plate comprising:
The negative photosensitive lithographic printing plate has a support and a photosensitive layer,
The support is an anodized aluminum support that has not been subjected to a silicate treatment; and
The photosensitive layer contains a compound having an unsaturated double bond group and a urethane bond group, an alkali-soluble resin and a near-infrared absorbing dye, and the compound having an unsaturated double bond group and a urethane bond group in the photosensitive layer The content in is 10 to 80% by mass,
Plate making method of lithographic printing plate.