JP2011138042A - Method of manufacturing planographic printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a planographic printing plate that has high developability and suppresses the generation of development scum with time, even if alkali developing solution of a relatively low pH is used. <P>SOLUTION: The method of manufacturing the planographic printing plate includes in this order: an exposure process of image-exposing a positive planographic printing original plate including an image recording layer containing (A) alkali-soluble resin having urea bond and phenolic hydroxyl group in a side chain and (B) compound for absorbing light and generating heat; and a developing process of developing the image-exposed positive planographic printing original plate using a pH 8.5-10.8 aqueous alkali solution containing an anionic surfactant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a lithographic printing plate, and more particularly to a method for producing a lithographic printing plate having excellent processability.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and printing ink repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). As described above, a difference in ink adhesion is caused on the surface of a lithographic printing plate, and after ink is applied only to an image portion, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (photosensitive layer, image recording layer) is provided on a hydrophilic support has been widely used. Yes. Usually, after the exposure process in which the lithographic printing plate precursor is subjected to image-like exposure through an original image such as a lithographic film, the image portion of the image recording layer remains, and other unnecessary image recording layers are formed. A lithographic printing plate is obtained by carrying out a development step of dissolving and removing with an alkaline developer or an organic solvent, and performing plate making by a method of forming a non-image portion by exposing the surface of the hydrophilic support.

  Thus, in the plate making process of the conventional lithographic printing plate precursor, after the exposure, a developing process for dissolving and removing unnecessary image recording layers with a developer or the like is required. It is desired to use an aqueous solution closer to the neutral range as an alkaline aqueous solution used in the above, or to reduce waste liquid in the development process. In particular, in recent years, disposal of waste liquid discharged with wet processing has become a major concern for the entire industry due to consideration for the global environment, and the demand for solving the above-mentioned problems has become stronger.

  On the other hand, in recent years, digitization technology for electronically processing, storing, and outputting image information by a computer has become widespread, and various new image output methods corresponding to such digitization technology will be put into practical use. It is becoming. Along with this, digitized image information is carried by high-convergence radiation such as laser light, and the lithographic printing plate precursor is scanned and exposed with the light, and directly through the lithographic printing plate Computer-to-plate (CTP) technology has been attracting attention. In particular, image recording materials compatible with infrared lasers have become widespread because they can be handled even under white light. As such an image recording material, a positive type image recording material utilizing a dissolution inhibiting effect on a developing solution expressed by an infrared absorbing dye having a photothermal conversion action and a phenol resin is attracting attention.

Usually, such a positive type image recording material is improved by the development process by eliminating the dissolution suppressing action in the exposed area by the infrared laser exposure and the heat generated by the photothermal conversion agent, thereby improving the solubility of the image recording layer. The area is removed and a lithographic printing plate is made. After the development, generally, a water washing treatment is performed to remove excess alkali developer, and then the lithographic printing plate is subjected to printing by gumming.
The development processing is usually performed in an automatic developing machine. However, when the image recording layer dissolved in the developer increases, the image is deposited and becomes development residue. When the development debris is remarkably generated, there is a concern that it may adhere to the lithographic printing plate after plate making and cause image failure. In particular, a relatively high molecular weight photothermal conversion agent is used for the image recording layer corresponding to the infrared laser, and a lithographic printing plate for high printing durability use has a high cohesive force and a high molecular weight as a polymer binder. Therefore, there is a tendency that development waste is likely to occur.

Furthermore, as an alkaline developer used in the development step, it is preferable to bring the pH close to neutral from the viewpoint of the environment, and various attempts have been made. For example, a plate making method has been proposed in which a lithographic printing plate precursor having a positive image recording layer having a multilayer structure is treated with a developer having a pH of 6 to 11 (see, for example, Patent Document 1). However, only by keeping the pH of the alkaline developer low, there is a problem in that when the plate is repeatedly made by an automatic processor, developability, in other words, development residue increases due to a decrease in solubility of the image recording layer. It has been found that there is a concern that the development residue may adhere to the plate surface and cause image failure.
Furthermore, in a lithographic printing plate, in order to increase the hydrophilicity of the non-image area and protect the plate surface, it is usually preferable to perform a hydrophilic treatment called a gumming treatment on the plate surface after development and washing with water. Since the processing is also a wet processing, there is a problem of waste liquid as in the development process.

International Publication 2009 / 094120A1 Specification

  The object of the present invention made in consideration of the above-mentioned problems is lithographic printing which has excellent developability and suppresses the development debris over time even when a relatively low pH alkaline developer is used. It is to provide a method for producing a plate.

  The method for producing a lithographic printing plate of the present invention comprises: (A) an alkali-soluble resin having a urea bond and a phenolic hydroxyl group in the side chain on a support; and (B) a compound that generates heat by absorbing light. , An exposure step for image exposure of a positive planographic printing plate precursor comprising an image recording layer, and a pH 8.5 to 10.8 containing an anionic surfactant. The development process which develops using the alkaline aqueous solution of this is included in this order.

The alkali-soluble resin is preferably a polymer containing a monomer having a urea bond and a phenolic hydroxyl group as a polymerization component. In addition to the monomer having a urea bond and a phenolic hydroxyl group, N -More preferred is a phenylmaleimide derivative or a copolymer containing an acrylic monomer having a sulfonamide group in the side chain.
Moreover, it is preferable that content of the water-soluble polymer compound in the said alkaline aqueous solution used for the image development process is 10 ppm or less.

Further, the image recording layer of the lithographic printing plate in the production method of the present invention is not limited to a single layer, but also (A) an alkali-soluble resin having a urea bond and a phenolic hydroxyl group in the side chain, and (B) absorbing light. A multilayer image recording layer comprising: a lower image recording layer containing a compound that generates heat; and an upper image recording layer containing an alkali-soluble resin formed on the lower image recording layer. May be.
Moreover, it is preferable that the said image development process is 1 bath process by alkaline aqueous solution. According to the production method of the present invention, after the development step using an alkaline aqueous solution having a relatively low pH, the plate was usually made without performing a widely performed rinse or water washing step or a gumming step. The lithographic printing plate can also be used for printing as it is. According to the production method of the present invention, even when such a one-bath treatment is performed, the development residue over time is effectively suppressed, so that the stability of the development system is excellent.

    According to the present invention, it is possible to provide a method for preparing a lithographic printing plate that is excellent in developability even when a relatively low pH alkaline developer is used, and that suppresses the development debris over time. it can.

It is a schematic sectional drawing which shows the one aspect | mode of the structure of the automatic processor which can be used for the preparation method of the lithographic printing plate of this invention.

Hereinafter, a method for producing a planographic printing plate of the present invention will be described in detail.
The method for producing a lithographic printing plate of the present invention comprises: (A) an alkali-soluble resin having a urea bond and a phenolic hydroxyl group in the side chain on a support; and (B) a compound that generates heat by absorbing light. , An exposure step for image exposure of a positive planographic printing plate precursor comprising an image recording layer, and a pH 8.5 to 10.8 containing an anionic surfactant. The development process which develops using the alkaline aqueous solution of this is included in this order.
Hereinafter, the constitution of the lithographic printing plate precursor to which the production method of the present invention can be applied, the exposure process, and the development process will be described in order.

<Lithographic printing plate precursor>
The lithographic printing plate precursor used in the production method of the present invention comprises (A) an alkali-soluble resin having urea bonds and phenolic hydroxyl groups in the side chain on the support, and (B) absorbing heat to generate heat. And a positive lithographic printing plate precursor comprising an image recording layer containing the compound.

[(A) Alkali-soluble resin having urea bond and phenolic hydroxyl group in side chain]
The (A) alkali-soluble resin having a urea bond and a phenolic hydroxyl group in the side chain (hereinafter referred to as a specific alkali-soluble resin as appropriate) that can be used in the present invention has a urea bond in the side chain and phenol as a substituent. There is no particular limitation as long as it has a functional hydroxyl group, but it is preferably a copolymer containing a monomer having a urea bond and a phenolic hydroxyl group as a polymerization component from the viewpoint of production suitability. An acrylic monomer having a urea bond and a phenolic hydroxyl group is preferred. As this acrylic monomer, the compound represented by the following general formula (d) is mentioned as a suitable thing, for example.

  In the general formula (d), R represents a hydrogen atom or an alkyl group. X represents a divalent linking group, and examples thereof include an alkylene group or a phenylene group which may have a substituent. Y represents a divalent aromatic group which may have a substituent, and examples thereof include a phenylene group or a naphthylene group which may have a substituent.

  Specific examples of the acrylic monomer represented by the general formula (d) include 1- (N ′-(4-hydroxyphenyl) ureido) methyl acrylate and 1- (N ′-(3-hydroxyphenyl) ureido. ) Methyl acrylate, 1- (N ′-(2-hydroxyphenyl) ureido) methyl acrylate, 1- (N ′-(3-hydroxy-4-methylphenyl) ureido) methyl acrylate, 1- (N ′-(2 -Hydroxy-5-methylphenyl) ureido) methyl acrylate, 1- (N '-(5-hydroxynaphthyl) ureido) methyl acrylate, 1- (N'-(2-hydroxy-5-phenylphenyl) ureido) methyl acrylate 2- (N ′-(4-hydroxyphenyl) ureido) ethyl acrylate, 2- (N ′-(3 Hydroxyphenyl) ureido) ethyl acrylate, 2- (N ′-(2-hydroxyphenyl) ureido) ethyl acrylate, 2- (N ′-(3-hydroxy-4-methylphenyl) ureido) ethyl acrylate, 2- (N '-(2-hydroxy-5-methylphenyl) ureido) ethyl acrylate, 2- (N'-(5-hydroxynaphthyl) ureido) ethyl acrylate, 2- (N '-(2-hydroxy-5-phenylphenyl) Ureido) ethyl acrylate, 4- (N ′-(4-hydroxyphenyl) ureido) butyl acrylate, 4- (N ′-(3-hydroxyphenyl) ureido) butyl acrylate, 4- (N ′-(2-hydroxyphenyl) ) Ureido) butyl acrylate, 4- (N ′-(3-hydroxy-4) Methylphenyl) ureido) butyl acrylate, 4- (N ′-(2-hydroxy-5-methylphenyl) ureido) butyl acrylate, 4- (N ′-(5-hydroxynaphthyl) ureido) butyl acrylate, 4- (N Acrylate derivatives such as'-(2-hydroxy-5-phenylphenyl) ureido) butyl acrylate;

1- (N ′-(4-hydroxyphenyl) ureido) methyl methacrylate, 1- (N ′-(3-hydroxyphenyl) ureido) methyl methacrylate, 1- (N ′-(2-hydroxyphenyl) ureido) methyl methacrylate 1- (N ′-(3-hydroxy-4-methylphenyl) ureido) methyl methacrylate, 1- (N ′-(2-hydroxy-5-methylphenyl) ureido) methyl methacrylate, 1- (N ′-( 5-hydroxynaphthyl) ureido) methyl methacrylate, 1- (N ′-(2-hydroxy-5-phenylphenyl) ureido) methyl methacrylate, 2- (N ′-(4-hydroxyphenyl) ureido) ethyl methacrylate, 2- (N '-(3-hydroxyphenyl) ureido) ethyl methacrylate, 2- (N'- (2-hydroxyphenyl) ureido) ethyl methacrylate, 2- (N ′-(3-hydroxy-4-methylphenyl) ureido) ethyl methacrylate, 2- (N ′-(2-hydroxy-5-methylphenyl) ureido) Ethyl methacrylate, 2- (N ′-(5-hydroxynaphthyl) ureido) ethyl methacrylate, 2- (N ′-(2-hydroxy-5-phenylphenyl) ureido) ethyl methacrylate, 4- (N ′-(4- Hydroxyphenyl) ureido) butyl methacrylate, 4- (N ′-(3-hydroxyphenyl) ureido) butyl methacrylate, 4- (N ′-(2-hydroxyphenyl) ureido) butyl methacrylate, 4- (N ′-(3 -Hydroxy-4-methylphenyl) ureido) butyl methacrylate, 4- (N ' (2-hydroxy-5-methylphenyl) ureido) butyl methacrylate, 4- (N ′-(5-hydroxynaphthyl) ureido) butyl methacrylate, 4- (N ′-(2-hydroxy-5-phenylphenyl) ureido) And methacrylate derivatives such as butyl methacrylate.
Among these, 2- (N ′-(4-hydroxyphenyl) ureido) ethyl methacrylate is preferably mentioned from the viewpoint of the balance between the effect of suppressing development residue over time and the image forming property and printing durability.

  There is no restriction | limiting in particular about the manufacturing method of the acrylate monomer shown by the said general formula (d), For example, the isocyanate compound represented by the following general formula (e), and the amine compound represented by the following general formula (f) A well-known manufacturing method etc. which are made to react are mentioned suitably.

In the general formula (e), R represents a hydrogen atom or an alkyl group. X has the same meaning as X in formula (d).
In the general formula (f), R ′ represents a hydrogen atom or an alkyl group which may have a substituent. Y has the same meaning as Y in the general formula (d). Z represents a hydroxyl group.
In the method for producing an evil relay and a monomer, by using the compound of the general formula (e) and the compound of the general formula (f) in which Z is a hydroxyl group and R ′ is a hydrogen atom, the general formula ( The polymerizable monomer represented by d) can be suitably obtained.

  In the said manufacturing method, since the amino group in General formula (f) has high activity with respect to an isocyanate group compared with a hydroxyl group or -NH-CO- group etc., it will be easily represented by the said General formula (d). A polymerizable acrylate monomer can be obtained. Further, if desired, the amine compound represented by the general formula (f) is made excessive, and the isocyanate compound represented by the general formula (e) is gradually added to the amine compound, thereby allowing the reaction to proceed more effectively. Can do.

Using a monomer having a urea bond and a phenolic hydroxyl group such as the acrylate monomer represented by the general formula (d), a polymer having a urea bond and a phenolic hydroxyl group in the side chain according to the present invention is produced. The method is not particularly limited and can be produced by various known methods. For example, a monomer having a urea bond and a phenolic hydroxyl group (polymerizable monomer) is used with a polymerization initiator. The method of superposing | polymerizing in a solvent is mentioned. In the method of polymerizing a polymerizable monomer in a solvent using a polymerization initiator, the polymerizable monomer includes one or more urea bonds, one or more polymerizable unsaturated bonds, and a substituent in one molecule. A monomer having a phenolic hydroxyl group as a monomer, and may be a homopolymer of such a monomer, but from the viewpoints of walling property and solubility in a coating solvent, a monomer containing no urea bond is used. A copolymer contained as a polymerization component is preferred.
For example, when synthesizing the specific alkali-soluble resin (A) containing the acrylate monomer represented by the general formula (d) as a polymerization component, the monomer content is 10 mol% to 80 mol in a charging ratio. %, More preferably 15 mol% to 70 mol%, and particularly preferably 20 mol% to 60 mol%. In the polymerization, the monomers represented by the general formula (d) may be used alone or in combination of two or more.

  The copolymer having a urea bond and a phenolic hydroxyl group in the side chain contains a compound having a polymerizable unsaturated bond and not containing a urea bond as a copolymerization component in an amount of 10 mol% to 80 mol%. Is preferred.

As a monomer having no urea bond contained in the specific alkali-soluble resin (A) of the present invention, an N-phenylmaleimide derivative or an acrylic monomer having a sulfonamide group in the side chain is suitable for printing durability and printing chemicals in UV ink printing. This is particularly preferable from the viewpoint of durability of the image recording layer.
Examples of the N-phenylmaleimide derivative include N-phenylmaleimide, N-2-methylphenylmaleimide, N-2,6-diethylphenylmaleimide, N-2-chlorophenylmaleimide, N-hydroxyphenylmaleimide and the like.

Examples of the acrylic monomer having a sulfonamide group in the side chain include m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like.
As the polymerizable monomer not containing a urea bond, a monomer other than the above N-phenylmaleimides and acrylic monomers having a sulfonamide group in the side chain may be used. Examples of the monomer that can be used include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, ethyl hexyl acrylate, octyl acrylate, chloroethyl acrylate, 2,2-dimethylhydroxypropyl acrylate, 5- Hydroxypentyl acrylate, glycidyl acrylate, benzyl acrylate, tetrahydro acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, benzyl methacrylate, black Benzyl methacrylate, octyl methacrylate, 4-hydroxybutyl methacrylate, furfuryl methacrylate, such as (meth) acrylic acid esters;

N-methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N-propylacrylamide, N-butylacrylamide, Nt-butylacrylamide, N-heptylacrylamide, N-benzylacrylamide, N-phenylacrylamide, N, (Meth) acrylamides such as N-dimethylacrylamide, N-methyl-N-phenylacrylamide, N-ethylmethacrylamide, N-phenylmethacrylamide, N, N-diethylmethacrylamide; vinyl butyrate, vinyl isobutyrate , Vinyl esters such as vinyl trimethyl acetate, vinyl diethyl acetate, vinyl benzoate, vinyl salicylate; maleic acid such as dimethyl malate, dibutyl fumarate or fumaric acid Dialkyl; N- cyclohexyl maleimide, such as maleimides of N- lauryl maleimide and the like; acrylonitrile, methacrylonitrile, and the like. These compounds may be used individually by 1 type, and may use 2 or more types together.
Of these compounds, (meth) acrylic acid esters, (meth) acrylamides, maleimides, and (meth) acrylonitriles are particularly preferable.

  In addition, in this specification, when referring to either or both of acrylate and methacrylate, when referring to either or both of (meth) acrylate and acryl and methacryl, (meth) acryl may be described, respectively. .

In a preferred embodiment of the (A) specific alkali-soluble resin in the present invention, the monomer represented by the general formula (d) is 10 mol% to 80 mol%, an N-phenylmaleimide derivative and an acrylic having a sulfonamide group in the side chain. 10 mol% to 80 mol% of monomers selected from monomers, 10 mol% of other acrylate monomers represented by (meth) acrylic acid esters, (meth) acrylamides, maleimides, and (meth) acrylonitriles A copolymer synthesized by containing ˜80 mol% can be mentioned.
As a molecular weight of (A) specific alkali-soluble resin which concerns on this invention, 2000 or more are preferable in a weight average molecular weight, and 3000-500,000 are more preferable. Moreover, in number average molecular weight, 1000 or more are preferable and 2000-400,000 are more preferable. As these molecular weight values, values calculated in terms of molecular weight of polystyrene standards by GPC (gel permeation chromatography) measurement are used.

[Other alkali-soluble resins]
In the image recording layer of the lithographic printing plate precursor used in the present invention, in addition to (A) the specific alkali-soluble resin and (B) a compound that generates heat by absorbing light described later, the (A) specific alkali-soluble resin is used. Other alkali-soluble resins not included in the resin may be included.
Other alkali-soluble resins that can be used in the present invention include alkali-soluble resins having a structure different from that of (A) and having a phenolic hydroxyl group in the molecule.
Examples of the resin having a phenolic hydroxyl group that can be used in the present invention include phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde resin, phenol / cresol (m-, p Any of-and m- / p-mixing) may be mentioned, including novolak resins such as mixed formaldehyde resins.

In addition, a t-butylphenol formaldehyde resin described in US Pat. No. 4,123,279 or a condensate of phenol and formaldehyde having an alkyl group having 3 to 8 carbon atoms as a substituent, such as octylphenol formaldehyde resin, is used in combination. Also good.
These resins having a phenolic hydroxyl group may be used alone or in combination of two or more.
(A) The molecular weight of the resin having a phenolic hydroxyl group having a structure different from that of the resin is preferably 500 to 20000 in terms of weight average molecular weight and 200 to 10,000 in terms of number average molecular weight.

(A) When a resin having a phenolic hydroxyl group having a structure different from that of the resin is used in combination, the mixing ratio with respect to the (A) specific alkali-soluble resin is preferably 1:10 to 10: 1 in terms of mass ratio. : 5 to 5: 1 is more preferable.
The blending ratio in the case of containing other alkali-soluble resin can obtain the effect of the combined use within the above numerical range. For example, the (A) resin and the (A) resin that can be used in combination have different structures. Sufficient interaction with the resin having a functional hydroxyl group is formed, development latitude is improved, and good chemical resistance is imparted to the image recording layer.

[(B) Compound that absorbs light and generates heat]
The image recording layer according to the present invention contains (B) a compound that absorbs light and generates heat (hereinafter, appropriately referred to as a photothermal conversion agent). As the (B) photothermal conversion agent that can be used in the present invention, various known pigments and dyes are preferably exemplified.
Examples of pigments include commercially available pigment and color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “Printing” Examples thereof include pigments described in "Ink Technology" (published by CMC Publishing, 1984).

Examples of the pigment include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments, blue pigments, green pigments, fluorescent pigments, metal powder pigments, and other polymer-bound dyes. It is done.
Specifically, for example, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments, perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinones Pigments, quinophthalone pigments, dyed lake pigments, azine pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like.

  The particle diameter of the pigment is preferably 0.01 to 10 μm, more preferably 0.05 to 1 μm, and particularly preferably 0.1 to 1 μm. When the particle diameter of the pigment is within the above range, the stability in the image recording layer coating solution is good, which is preferable in terms of uniformity in the image recording layer.

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

  Carbon black is preferably used as the pigment that absorbs the infrared light or near infrared light. Examples of the dye that absorbs the infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, and JP-A-60-78787. Methine dyes described in JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, etc., JP-A-58-112793, Naphthoquinone dyes described in JP-A-58-224793, JP-A-59-48187, JP-A-59-73996, JP-A-60-52940, JP-A-60-63744, etc. Examples thereof include squarylium dyes described in JP-A-58-112792, and cyanine dyes described in British Patent 434,875.

Further, as the dye, a near-infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and substituted arylbenzo (described in US Pat. No. 3,881,924) Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (US Pat. No. 4,327,169), JP-A-58-181051, 58-220143, 59-41363 59-84248, 59-84249, 59-146063, 59-146061, pyranyl compounds described in JP-A-59-216146, cyanine dyes described in US Pat. The pentamethine thiopyrylium salt described in No. 283,475 and the pyrilylation disclosed in Japanese Patent Publication Nos. 5-13514 and 5-19702 Things, Epolight III-178, EpolightIII-130, Epolight III-125, EpolightV-176A or the like is used particularly preferably.
Another particularly preferred example of the dye is a near-infrared absorbing dye described in US Pat. No. 4,756,993 as formulas (I) and (II).

(B) As addition amount in the image recording layer of a photothermal conversion agent, 0.01-50 mass% is preferable with respect to the total solid, and 0.1-10 mass% is more preferable. When a dye is used as the photothermal conversion agent, the addition amount is particularly preferably 0.5 to 10% by mass, and when the pigment is used, the addition amount is particularly preferably 3.1 to 10% by mass.
(B) When the addition amount of the photothermal conversion agent is within the above range, there is no concern that a sufficient sensitivity improvement effect can be obtained and the uniformity of the image recording layer is lost or the durability of the recording layer is lowered.

  The (B) photothermal conversion agent such as the dye or pigment may be added to the same layer as other components or may be added to another layer. When added to a layer different from other components, it is added to the layer adjacent to the layer containing a substance that is thermally decomposable and substantially reduces the solubility of the binder resin when not decomposed. It is preferable to do this. Moreover, although it is preferable that the said dye or pigment and (A) specific alkali-soluble resin are contained in the same layer, they may be contained in another layer.

[Other ingredients]
If desired, the image recording layer may contain (A) a specific alkali-soluble resin, (B) a photothermal conversion agent, and other alkali-soluble resins that are optionally added, and other additives depending on the purpose. Can do.
Examples of other components include various additives such as onium salts, o-quinonediazide compounds, aromatic sulfone compounds, aromatic sulfonic acid ester compounds, and the like (A) Examples include substances that substantially reduce the solubility of the aqueous alkali-soluble resin. By using the additive, it is possible to improve the dissolution inhibition property of the image portion in the developer.

Examples of the onium salt include diazonium salt, ammonium salt, phosphonium salt, iodonium salt, sulfonium salt, selenonium salt, arsonium salt and the like.
Examples of onium salts include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T .; S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230, U.S. Pat. Nos. 4,069,055, 4,069,056, JP-A-3-140140. Ammonium salts described in the specification of C. Necker et al, Macromolecules, 17, 2468 (1984), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat. Nos. 4,069,055 and 4,069,056; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), Chem. &Amp; Eng. News, Nov. 28, p31 (1988), European Patent No. 104,143, U.S. Pat. Nos. 339,049, 410,201, JP-A-2-150848, JP-A-2-296514,

J. et al. V. Crivello et al, Polymer J. et al. 17, 73 (1985), J. Am. V. Crivello et al. J. et al. Org. Chem. , 43, 3055 (1978), W.M. R. Watt et al. Polymer Sci. , Polymer Chem. Ed. , 22, 1789 (1984), J. Am. V. Crivello et al, Polymer Bull. , 14, 279 (1985), J. et al. V. Crivello et al, Macromolecules, 14 (5), 1141 (1981), J. MoI. V. Crivello et al, J. MoI. Polymer Sci. , Polymer Chem. Ed. , 17, 2877 (1979), European Patent Nos. 370,693, 233,567, 297,443, 297,442, US Pat. Nos. 4,933,377, 3,902,114 Nos. 410, 201, 339, 049, 4, 760, 013, 4, 734, 444, 2, 833, 827, German Patent No. 2,904, 626, Sulfonium salts described in JP-A-3,604,580 and JP-A-3,604,581; V. Crivello et al, Macromolecules, 10 (6), 1307 (1977), J. MoI. V. Crivello et al, J. MoI. Polymer Sci. , Polymer Chem. Ed. , 17, 1047 (1979), C.I. S. Wen et al, Teh, Proc. Conf. Rad. Preferred examples include arsonium salts described in Curing ASIA, p478 Tokyo, Oct (1988).
Among these, a diazonium salt is particularly preferable, and the diazonium salt described in JP-A-5-158230 is preferable.

  Counter ions of onium salts include tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid 2-nitrobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfone An acid, p-toluenesulfonic acid, etc. can be mentioned. Among these, particularly preferred are alkyl aromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid.

  Examples of the o-quinonediazide compound include compounds having various structures as long as they are compounds having one or more o-quinonediazide groups and increase alkali solubility by thermal decomposition. The o-quinonediazide has both the effect of losing the ability to suppress the dissolution of the binder by thermal decomposition and the effect of the o-quinonediazide itself changing to an alkali-soluble substance. Can act as an accelerator.

  As addition amount of additives other than an o-quinonediazide compound, 1-50 mass% is preferable, 5-30 mass% is more preferable, and 10-30 mass% is especially preferable. The additive and the binder are preferably contained in the same layer.

Further, for the purpose of further improving sensitivity, cyclic acid anhydrides, phenols, and organic acids can be added. Examples of the cyclic acid anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, maleic anhydride, succinic anhydride, pyromellitic anhydride, and the like.
Examples of the phenols include bisphenol A, p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ′, 4 ″ -trihydroxy. Examples include triphenylmethane, 4,4 ′, 3 ″, 4 ″ -tetrahydroxy-3,5,3 ′, 5′-tetramethyltriphenylmethane.

Examples of the acids include sulfonic acids, sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphate esters, and carboxylic acids. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid , Ethyl sulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 4- Examples include cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, and ascorbic acid.
As a ratio which occupies in the printing plate material of the said cyclic acid anhydride, phenols, or organic acids, 0.05-20 mass% is preferable, 0.1-15 mass% is more preferable, 0.1-10 mass% Is particularly preferred.

  In order to improve the coating property, the image recording layer may contain a surfactant, for example, a fluorine-based surfactant described in JP-A No. 62-170950. As content of this surfactant, 0.01-1 mass% of the said image forming material is preferable, and 0.05-0.5 mass% is more preferable. Further, in order to broaden the processing stability with respect to the developing conditions, nonionic surfactants such as those described in JP-A Nos. 62-251740 and 3-208514, JP-A No. 59-121044 are disclosed. , Amphoteric surfactants as described in JP-A-4-13149 can be contained.

Examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine type. Is mentioned.
The content of the nonionic surfactant and the amphoteric surfactant in the image forming material is preferably 0.05 to 15% by mass, and more preferably 0.1 to 5% by mass.

  The image recording layer can contain a printing-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant. Typical examples of the printing-out agent include a combination of a compound that releases an acid by heating by exposure (photoacid releasing agent) and an organic dye that can form a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halides and salt-forming organic dyes described in JP-A-50-36209 and JP-A-53-8128, No. -36223, 54-74728, 60-3626, 61-143748, 61-151644 and 63-58440, and trihalomethyl compounds and salt-forming organic dyes Can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent temporal stability and give clear printout images.

Various dyes can be used as the colorant used for improving the visibility of the image area. Suitable dyes include oil-soluble dyes and basic dyes. Specifically, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (manufactured by Orient Chemical Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI 42555) ), Methyl violet (CI42535), ethyl violet, rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI522015), and the like. The dyes described in JP-A-62-293247 are particularly preferred.
The content of these dyes is preferably 0.01 to 10% by mass, more preferably 0.1 to 3% by mass, based on the total solid content of the image forming material.

  Further, if necessary, a plasticizer may be added to the image forming layer in order to impart flexibility or the like of the image recording layer. Examples of the plasticizer include butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, Acrylic acid or methacrylic acid oligomers and polymers are used.

[Formation of planographic printing plate precursor]
The positive lithographic printing plate precursor used in the production method of the present invention is formed by applying an image recording layer coating solution prepared by dissolving the above components in a solvent onto a support described later.

[Support]
As the support used for the lithographic printing plate precursor, a dimensionally stable plate-like material is preferable. For example, paper, paper laminated with plastic, metal plate (for example, aluminum, copper, etc.), plastic film (for example, Cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, polyethylene terephthalate, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic film on which a metal as described above is laminated or deposited.
Among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. Even if the content of the different elements in the alloy is large, it is 10% by mass or less. The thickness of the aluminum plate is preferably about 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and particularly preferably 0.2 to 0.3 mm.

The aluminum plate is subjected to various surface treatments such as roughening and anodizing treatment.
Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant, an organic solvent, or an alkaline aqueous solution for removing rolling oil on the surface is performed as desired. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically dissolving and roughening a surface, and a method of selectively dissolving a surface chemically. This is done by the method of As the mechanical method, a known method such as a ball polishing method, a brush polishing method, a blast polishing method, or a buff polishing method can be used. Further, as an electrochemical surface roughening method, there is a method of performing alternating current or direct current in hydrochloric acid or nitric acid electrolyte. Further, as disclosed in JP-A-54-63902, a method in which both are combined can also be used.

  The roughened aluminum plate is subjected to an alkali etching treatment and a neutralization treatment as necessary, and then anodized to enhance the water retention and wear resistance of the surface as desired. As the electrolyte used for the anodizing treatment of the aluminum plate, various electrolytes that form a porous oxide film can be used. In general, sulfuric acid, phosphoric acid, oxalic acid, or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The conditions for the anodizing treatment vary depending on the electrolyte used, and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 80% by mass solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 It is preferable that it is -60A / dm2, a voltage is 1-100V, and electrolysis time is 10 second-5 minutes. The amount of the anodized film by the anodization is preferably 1.0 g / m ² or more. When the amount of the anodic oxide film is less than 1.0 g / m ² , the printing durability is insufficient, or when used as a lithographic printing plate, the non-image area may be easily damaged. As a result, a so-called “scratch stain” in which ink adheres to a scratched part during printing may be likely to occur.

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

  The solvent is not particularly limited, and known solvents such as ethylene dichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol, propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol, 2-methoxyethyl acetate, 1- Methoxy-2-propyl acetate, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyrolactone, toluene, etc. Is mentioned. These solvents may be used alone or in a combination of two or more.

The concentration of each component (total solid content including additives) of the image recording layer coating solution in the solvent is preferably 1 to 50% by mass. Further, the coating amount (solid content) of the image recording layer on the support obtained after coating and drying varies depending on the use, but is generally preferably 0.5 to 5.0 g / m ² . As the coating amount decreases, the apparent sensitivity increases, but the film characteristics of the image recording layer decrease.

The lithographic printing plate precursor according to the invention may take the form of an image recording layer having not only a single layer structure but also a multilayer structure. When taking a multi-layer structure, an image recording layer (lower image recording layer) containing the (A) specific alkali-soluble resin and (B) a photothermal conversion agent is provided on the side close to the support, It is preferable to take an embodiment in which two image recording layers (upper image recording layers) are provided. The second image recording layer may be an image recording layer having a positive photosensitive property or a layer having no photosensitive layer. In the case of a positive photosensitive image recording layer, the prescription thereof is used. Although there is no restriction | limiting in particular, It is preferable to contain urethane type resin as alkali-soluble resin. Further, when the upper image recording layer does not have photosensitivity, a design using heat generated in the lower image recording layer is a preferred embodiment from the viewpoint of suppressing ablation scattering during exposure.
When the image recording layer of the lithographic printing plate precursor according to the present invention has a multi-layer structure, the coating amount after drying of the lower image recording layer provided on the side close to the support is to ensure printing durability. in terms of residual film suppressing generation during development it is preferably in the range of 0.5 to 1.5 g / m ^2, more preferably in the range of 0.7 to 1.2 g / m ^2.
The coating amount after drying of the upper image recording layer is preferably in the range of 0.05 to 1.0 g / m ^2, more preferably in the range of 0.07~0.7g / m ^2.

  The coating method is not particularly limited, and examples thereof include known coating methods such as bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.

  In the lithographic printing plate precursor according to the invention, an undercoat layer can be provided between the support and the image recording layer as desired. As the component of the undercoat layer, various organic compounds are used. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and optionally substituted phenyl Organic phosphonic acids such as phosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid and glyceroline Organic phosphoric acid such as acid, optionally substituted phenylphosphinic acid, naphthylphosphinic acid, organic phosphinic acid such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and triethanolamine Hydride such as hydrochloride Hydrochloride salts of amines having a carboxy group. These may be used individually by 1 type and may use 2 or more types together.

  The undercoat layer can be provided by the following method. That is, a method in which water or an organic solvent such as methanol, ethanol, methyl ethyl ketone, or a mixed solvent thereof is applied on an aluminum plate and dried to provide a solution, or water, methanol, ethanol, methyl ethyl ketone, or the like. For example, an aluminum plate is immersed in a solution in which the organic compound is dissolved in an organic solvent or a mixed solvent thereof to adsorb the compound, and then washed and dried with water or the like.

  In the former method, the concentration of the organic compound in the solution in which the organic compound is dissolved is preferably 0.005 to 10% by mass. In the latter method, the concentration of the organic compound in the solution in which the organic compound is dissolved is preferably 0.01 to 20% by mass, more preferably 0.05 to 5% by mass, The temperature is preferably 20 to 90 ° C, more preferably 25 to 50 ° C, and the immersion time is preferably 0.1 second to 20 minutes, and more preferably 2 seconds to 1 minute.

The solution in which the organic compound is dissolved may contain a basic substance such as ammonia, triethylamine or potassium hydroxide, or an acidic substance such as hydrochloric acid or phosphoric acid to adjust the pH to 1 to 12. A yellow dye can also be added to improve the tone reproducibility of the image forming material.
The coating amount of the organic undercoat layer is preferably ² to 200 mg / m ^{2 and} more preferably 5 to 100 mg / m ² . If the coating amount is out of the numerical range, sufficient printing durability may not be obtained.

In the lithographic printing plate precursor according to the invention, an overcoat can be provided on the image recording layer as desired. As the component of the overcoat, an alkali-soluble polyurethane resin is preferable, and among them, a polyurethane resin having a carboxyl group in the polymer main chain which is a reaction product of an isocyanate compound and a diol compound having a carboxyl group can be mentioned. The isocyanate for producing the polyurethane resin is preferably an aromatic diisocyanate such as tolylene diisocyanate, and the diol is preferably 3,5-dihydroxybenzoic acid or 2,2-bis (hydroxymethyl) propionic acid.
In this way, a lithographic printing plate precursor used in the lithographic printing plate preparation method of the present invention is obtained.

<Preparation method of lithographic printing plate>
The lithographic printing plate precursor obtained as described above is usually subjected to image exposure and development treatment to produce a lithographic printing plate. That is, in a negative lithographic printing plate precursor exposed to a desired image quality, the solubility of the exposed area in an alkaline developer is improved, and it is removed by development to form a non-image area. The recording layer becomes the image portion of the lithographic printing plate.
[Exposure process]
Examples of the active light source used for exposure include a mercury lamp, a metal halide lamp, a xenon lamp, a chemical lamp, and a carbon arc lamp. Examples of radiation include electron beams, X-rays, ion beams, and far infrared rays. Also, g-line, i-line, deep-UV light, and high-density energy beam (laser beam) are used. Examples of the laser beam include a helium / neon laser, an argon laser, a krypton laser, a helium / cadmium laser, and a KrF excimer laser.
The image-like exposure may be performed by exposure through a mask such as a lith film, or may be performed by scanning exposure.
In the present invention, a light source having a light emission wavelength from the near infrared region to the infrared region is preferable, and a solid laser or a semiconductor laser is particularly preferable.

[Development process]
Next, the development process will be described in detail.
(Specific developer)
A processing solution (hereinafter also referred to as a specific developing solution) used in the developing step is an alkaline aqueous solution having a pH of 8.5 to 10.8 containing an anionic surfactant. An anionic surfactant contributes to the improvement of processability.

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

As the anionic surfactant used in the treatment liquid of the present invention, an anionic surfactant containing a sulfonic acid or a sulfonate is particularly preferable.
Anionic surfactants can be used alone or in combination.
The content of the anionic surfactant in the developer is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, and most preferably 2 to 10% by mass.

The specific developer according to the present invention needs to have a pH of 8.5 to 10.8. In order to keep the pH of the developer in the above range, it is preferable that carbonate ions and hydrogen carbonate ions exist as buffering agents. Due to the functions of carbonate ions and hydrogen carbonate ions, it is considered that the change in pH can be suppressed even when the developer is used for a long period of time, and the development loss due to the change in pH, the development of development residue, and the like can be suppressed. In order to allow carbonate ions and hydrogen carbonate ions to be present in the developer, carbonate and hydrogen carbonate may be added to the developer, or by adjusting the pH after adding carbonate or bicarbonate, Ions and bicarbonate ions may be generated.
The carbonate and hydrogen carbonate that can be used for adjusting the pH are not particularly limited, but are preferably alkali metal salts. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. These may be used alone or in combination of two or more.
The pH of the developer may be any pH that causes a buffering action, and specifically needs to be in the range of pH 8.5 to 10.8. When the pH is less than 8.5, the developability of the non-image area is lowered.

  0.3-20 mass% is preferable with respect to the mass of alkaline aqueous solution, and, as for the total amount of carbonate and hydrogencarbonate, 0.5-10 mass% is more preferable, and 1-5 mass% is especially preferable. When the total amount is 0.3% by mass or more, developability and processing capacity do not decrease, and when it is 20% by mass or less, it becomes difficult to form precipitates and crystals. It becomes difficult to gel and does not interfere with waste liquid treatment.

Further, for the purpose of assisting the fine adjustment of the alkali concentration and the dissolution of the non-image area photosensitive layer, another alkali agent such as an organic alkali agent may be supplementarily used together. Examples of the organic alkali agent include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, Examples thereof include diisopropanolamine, ethyleneimine, ethylenediamine, pyridine, tetramethylammonium hydroxide and the like. Examples of inorganic salts include primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, and the like.
These other alkaline agents are used alone or in combination of two or more. In addition to the above, the treatment liquid of the present invention may contain a wetting agent, preservative, chelate compound, antifoaming agent, organic acid, organic solvent, inorganic acid, inorganic salt, and the like.
However, if the specific developer contains a water-soluble polymer compound, there is a concern that the plate surface is likely to be sticky especially when the processing solution is fatigued, so the content of the water-soluble polymer compound in the specific developer according to the present invention is It is preferably 10 ppm or less, more preferably 5 ppm or less, and most preferably not contained. Examples of the “water-soluble polymer compound” herein include polymer compounds used as a water-soluble binder polymer. For example, a hydroxyl group, carboxyl group, carboxylate group, hydroxyethyl group, Hydrophilic group selected from oxyethyl group, hydroxypropyl group, polyoxypropyl group, amino group, aminoethyl group, aminopropyl group, ammonium group, amide group, carboxymethyl group, sulfo group, phosphate group, etc. The polymer compound having
Specific examples include, for example, gum arabic, casein, gelatin, starch derivatives, carboxymethylcellulose and its sodium salt, cellulose acetate, sodium alginate, vinyl acetate-maleic acid copolymers, styrene-maleic acid copolymers, polyacrylic acids and the like. Salts, polymethacrylic acids and their salts, hydroxyethyl methacrylate homopolymers and copolymers, hydroxyethyl acrylate homopolymers and copolymers, hydroxypyrrole methacrylate homopolymers and copolymers, hydroxypropyl acrylate homopolymers and copolymers, hydroxybutyl Methacrylate homopolymers and copolymers, hydroxybutyl acrylate homopolymers and copolymers, polyesters Lenglycols, hydroxypropylene polymers, polyvinyl alcohol, hydrolyzed polyvinyl acetate, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, homopolymers and copolymers of acrylamide having a hydrolysis degree of 60 mol% or more, preferably 80 mol% or more, methacryl Homopolymers and copolymers of amides, homopolymers and copolymers of N-methylolacrylamide, polyvinylpyrrolidone, alcohol-soluble nylon, polyethers of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. .

  Preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzoisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, benztriazole derivatives Amiding anidine derivatives, quaternary ammonium salts, derivatives such as pyridine, quinoline, guanidine, diazine, triazole derivatives, oxazole, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diol, 1, 1-dibromo-1-nitro-2-ethanol, 1,1-dibromo-1-nitro-2-propanol and the like can be preferably used. It is preferable to use two or more kinds of preservatives in combination so as to be effective against various molds and sterilization. The addition amount of the preservative is an amount that stably exerts an effect on bacteria, mold, yeast, etc., and varies depending on the type of bacteria, mold, yeast, but 0.01 to 4 relative to the treatment liquid. A range of mass% is preferred.

  Examples of the chelate compound include ethylenediaminetetraacetic acid, potassium salt thereof, sodium salt thereof; diethylenetriaminepentaacetic acid, potassium salt thereof, sodium salt thereof; triethylenetetraminehexaacetic acid, potassium salt thereof, sodium salt thereof, hydroxyethylethylenediaminetriacetic acid Nitrilotriacetic acid, sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, potassium salt, sodium salt; aminotri (methylenephosphonic acid), potassium salt, sodium salt And organic phosphonic acids and phosphonoalkanetricarboxylic acids. Organic amine salts are also effective in place of the sodium and potassium salts of the chelating agents. A chelating agent is selected that is stably present in the treatment liquid composition and does not impair the printability. The addition amount is preferably 0.001 to 1.0% by mass with respect to the treatment liquid.

  As the antifoaming agent, a general silicon-based self-emulsifying type, emulsifying type, nonionic HLB 5 or less compound can be used. Silicon antifoaming agents are preferred. Among them, emulsification dispersion type and solubilization can be used. The content of the antifoaming agent is preferably in the range of 0.001 to 1.0 mass% with respect to the treatment liquid.

  Examples of organic acids include citric acid, acetic acid, succinic acid, malonic acid, salicylic acid, caprylic acid, tartaric acid, malic acid, lactic acid, levulinic acid, p-toluenesulfonic acid, xylenesulfonic acid, phytic acid, and organic phosphonic acid. . The organic acid can also be used in the form of its alkali metal salt or ammonium salt. The content of the organic acid is preferably 0.01 to 0.5% by mass with respect to the treatment liquid.

  Examples of the organic solvent include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (produced by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.) ) Or halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichrene, monochlorobenzene, etc.) and polar solvents.

Polar solvents include alcohols (methanol, ethanol, isopropanol, benzyl alcohol, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monomethyl ether, ethylene glycol monobenzyl ether, ethylene Glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, etc.), ketones (acetone, methyl ethyl ketone, cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, benzyl acetate, methyl lactate, Propylene glycol monomethyl ether acetate, diethyl phthalate, butyl levulinate, etc. Other (triethyl phosphate, tricresyl phosphate, N- phenylethanolamine, N- phenyldiethanolamine, etc.) and the like.
Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, Examples thereof include sodium hydrogen sulfate and nickel sulfate. The content of the inorganic salt is preferably 0.01 to 0.5% by mass based on the total mass of the treatment liquid.

  When the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. When the developer contains an organic solvent, the concentration of the solvent is preferably less than 40% by mass from the viewpoint of safety and flammability.

(Development conditions)
The development temperature is usually 60 ° C. or lower, preferably about 15 to 40 ° C. In the developing process using an automatic developing machine, the developing solution may be fatigued depending on the amount of processing, and thus the processing capability may be restored by using a replenishing solution or a fresh developing solution.
In the normal development processing step, alkali development is performed, alkali is removed in the post-water washing step, gum processing is performed in the gumming step, and drying is performed in the drying step. By using an aqueous solution containing hydrogen ions and an anionic surfactant, pre-water washing, development and gumming are performed simultaneously. Therefore, the pre-water washing step is not particularly required, and the drying step can be performed only by using one liquid, and further after performing pre-water washing, development and gumming in one bath. After development, it is preferable to dry after removing excess processing liquid using a squeeze roller or the like.

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

The rotating brush roll used in the present invention can be appropriately selected in consideration of the difficulty of scratching the image area and the stiffness of the support of the lithographic printing plate precursor. As the rotating brush roll, a known one formed by planting a brush material on a plastic or metal roll can be used. For example, as described in Japanese Patent Application Laid-Open Nos. 58-159533 and 3-100554, or as disclosed in Japanese Utility Model Publication No. 62-167253, metal or plastic in which brush materials are implanted in rows A brush roll can be used in which the groove mold material is radially wound around a plastic or metal roll as a core without a gap.
Examples of brush materials include plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylics such as polyacrylonitrile and poly (meth) acrylate). , Polyolefin synthetic fibers such as polypropylene and polystyrene). For example, fibers having a hair diameter of 20 to 400 μm and a hair length of 5 to 30 mm can be preferably used.
The outer diameter of the rotating brush roll is preferably 30 to 200 mm, and the peripheral speed at the tip of the brush rubbing the plate surface is preferably 0.1 to 5 m / sec. It is preferable to use a plurality of rotating brush rolls.

  The rotating direction of the rotating brush roll may be the same or opposite to the conveying direction of the lithographic printing plate precursor. However, when two or more rotating brush rolls are used, at least one rotating brush roll is used. It is preferred that the rotating brush rolls rotate in the same direction and at least one rotating brush roll rotates in the opposite direction. This further ensures the removal of the photosensitive layer in the non-image area. It is also effective to swing the rotating brush roll in the direction of the rotation axis of the brush roll.

  It is preferable to provide a drying step continuously or discontinuously after the development step. Drying is performed by hot air, infrared rays, far infrared rays, or the like.

  An example of the structure of an automatic processor suitably used in the method for producing a lithographic printing plate of the present invention is schematically shown in FIG. The automatic processor shown in FIG. 1 basically includes a developing unit 6 and a drying unit 10, and the lithographic printing plate precursor 4 is developed and gummed in the developing tank 20 and dried in the drying unit 10.

The lithographic printing plate obtained as described above can be subjected to a printing process. However, when it is desired to obtain a lithographic printing plate having a higher printing durability, a burning process is performed. In the case of burning a lithographic printing plate, the preparation as described in JP-B-61-2518, JP-A-55-28062, JP-A-62-31859, and JP-A-61-159655 is performed before burning. It is preferable to treat with a surface liquid. The lithographic printing plate coated with the surface-adjusting solution is dried if necessary, and then heated to a high temperature with a burning processor (for example, burning processor “BP-1300” sold by Fuji Photo Film Co., Ltd.). Is done. The heating temperature and time in this case are preferably about 1 to 20 minutes at a temperature of 180 to 300 ° C., although it depends on the type of components forming the image. The heating conditions are appropriately selected depending on the type of the lithographic printing plate precursor to be used. In general, when the temperature is too low, when the heating time is insufficient, sufficient image strengthening action cannot be obtained, and the temperature is If it is too high or if the heating time is too long, problems such as deterioration of the support and thermal decomposition of the image area may occur.
The lithographic printing plate thus obtained is loaded on an offset printing machine and used for printing a large number of sheets.

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

[(A) Synthesis of specific alkali-soluble resin]
<Synthesis Example 1: (A) Synthesis of specific alkali-soluble resin 1>
1-1. Synthesis of Polymer Compound Containing Polymerizable Monomer After adding 15.5 g of methacryloyloxyethyl isocyanate and 12.0 g of 4-aminophenol to 150 g of dioxane solvent, this was stirred for 2 hours, and the following constitution 25.0 g of 2- (N ′-(4-hydroxyphenyl) ureido) ethyl methacrylate having units was obtained.

1-2. (A) Synthesis of specific alkali-soluble resin 1
The obtained 2- (N ′-(4-hydroxyphenyl) ureido) ethyl methacrylate and N-phenylmaleimide (monomer not containing a urea bond) were mixed in a mass ratio [2- (N ′-(4-hydroxyphenyl). ) Ureido) ethyl methacrylate / N-phenylmaleimide)] was polymerized at a ratio of 75/25 to obtain 20 g of (A) specific alkali-soluble resin 1 (weight average molecular weight (Mw) = 16,000).

<Synthesis Example 2: (A) Synthesis of specific alkali-soluble resin 2>
In the synthesis of (A) the specific alkali-soluble resin 1 in Synthesis Example 1, N- (p-aminosulfonylphenyl) methacrylamide is used instead of N-phenylmaleimide, which is a monomer not containing a urea bond, used as a copolymerization component. Except that the mass ratio [2- (N ′-(4-hydroxyphenyl) ureido) ethyl methacrylate / N- (p-aminosulfonylphenyl) methacrylamide] was polymerized at a ratio of 75/25. In the same manner as in Example 1, 20 g of (A) specific alkali-soluble resin 2 (weight average molecular weight (Mw) = 34,000) was obtained.

<Synthesis Example 3: (A) Synthesis of specific alkali-soluble resin 3>
In the synthesis of (A) the specific alkali-soluble resin 1 in Synthesis Example 1, instead of N-phenylmaleimide, which is a monomer not containing a urea bond, used as a copolymerization component, methyl methacrylate and methacrylamide were used, and the mass ratio was Except that [2- (N ′-(4-hydroxyphenyl) ureido) ethyl methacrylate / methyl methacrylate / methacrylamide] was polymerized at a ratio of 72/14/14, the same as in Synthesis Example 1 ( A) 20 g of the specific alkali-soluble resin 3 (weight average molecular weight (Mw) = 68,000) was obtained.

<Synthesis Example 4: (A) Synthesis of specific alkali-soluble resin 4>
In the synthesis of (A) the specific alkali-soluble resin 1 in Synthesis Example 1, acrylonitrile and methacrylamide were used instead of N-phenylmaleimide which is a monomer not containing a urea bond used as a copolymerization component, and the mass ratio [2 -(N '-(4-hydroxyphenyl) ureido) ethyl methacrylate / methyl methacrylate / methacrylamide] was polymerized in a ratio of 65/20/15 in the same manner as in Synthesis Example 1, except that (A) specified 20 g of alkali-soluble resin 4 weight average molecular weight (Mw) = 45,000) was obtained.

<Synthesis Example 5: Synthesis of Comparative Alkali-soluble Resin A>
After 11.9 g of phenyl isocyanate and 12.0 g of 4-aminophenol were added to 120 g of dioxane solvent and dissolved, the mixture was stirred for 2 hours to obtain 22.0 g of 4- (N′-phenylureido) phenol.
18.3 g of the obtained 4- (N′-phenylureido) phenol and 2.40 g of paraformaldehyde were dissolved in 100 g of oxalic acid, stirred and heated to 100 ° C. 20 g of a comparative alkali-soluble resin (weight average molecular weight (Mw) = 2,000) having a urea bond in the represented side chain but not having a phenolic hydroxyl group as a substituent was obtained.

In said structural formula, n is 1-15, Ph in () is a benzene ring.
<Comparison alkali-soluble resin B>
As comparative alkali-soluble resin B, N-phenylmaleimide / methacrylic acid / methacrylamide (60/15/25) weight average molecular weight 44,000 was used.

<Examples 1-5 and Comparative Examples 1-3>
[Preparation of Support A]
An aluminum plate (material 1050) having a thickness of 0.3 mm was washed with trichlorethylene and degreased, and then the surface was grained using a nylon brush and a 400 mesh pumice-water suspension and thoroughly washed with water. This plate was etched by being immersed in a 25% aqueous sodium hydroxide solution at 45 ° C. for 9 seconds, washed with water, further immersed in 20% nitric acid for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² . Next, this plate was provided with a direct current anodic oxide coating of 3 g / m ² at a current density of 15 A / dm ² using 7% sulfuric acid as an electrolyte, then washed with water, dried, and further coated with the following undercoat solution. Was dried at 90 ° C. for 1 minute to obtain a support A provided with an undercoat layer. The coating amount after drying was 10 mg / m ² .

-Undercoat liquid-
・ Β-Alanine 0.5g
・ Methanol 95g
・ Water 5g

An image recording layer coating solution 1 containing the following components is applied to the obtained undercoated support A so that the coating amount is 1.2 g / m ^2, and the lithographic printing plate precursors 1 to 4 and Comparative lithographic printing plate precursors 1 and 2 were obtained.
-Image recording layer coating solution 1-
(A) Specific alkali-soluble resin or comparative alkali-soluble resin (compound described in Table 1)
0.80g
・ M, p-cresol novolak (m, p ratio = 6 / 0.20 g
4, weight average molecular weight = 3,500, containing 0.5% by mass of unreacted cresol)
・ 0.003 g of p-toluenesulfonic acid
・ Tetrahydrophthalic anhydride 0.03g
-Dye A having the following structure [(B) photothermal conversion agent] 0.017 g
・ Victory Pure Blue BOH counter ion 1-0.015g
Dye made from naphthalene sulfonate anion, Megafac F-177 (Dainippon Ink & Chemicals, 0.05 g
(Fluorosurfactant manufactured by Co., Ltd.)
・ Γ-Butyllactone 10g
・ Methyl ethyl ketone 10g
・ 8g of 1-methoxy-2-propanol

(Preparation of lithographic printing plate precursor 5)
On the image recording layer (coating amount: 1.0 mg / m ² ) similar to that of the lithographic printing plate precursor 1, a bar coater is applied so that the coating amount for the upper layer is further 0.5 g / m ^2. After that, it was dried at 130 ° C. for 40 seconds and further slowly cooled by wind at 20 to 26 ° C. to prepare a lithographic printing plate precursor 5 according to the present invention having a multilayer image recording layer.
-Upper layer coating solution-
・ Condensed polyurethane resin with 4,4′-diphenylmethane diisocyanate / tolylene diisocyanate / 2,2-bis (hydroxymethyl) propionic acid / decanediol = 40/10/40/10 (weight average molecular weight 28,000)
30.0g
・ Ethyl violet 0.03g
・ Megafuck F-177 0.05g
・ 3-Pentanone 60g
・ Propylene glycol monomethyl ether-2-acetate 8g

-Evaluation-
(Exposure process)
The obtained lithographic printing plate precursors 1 to 5 and comparative lithographic printing plate precursors 1 and 2 according to the present invention were exposed (laser power: 8.5 W) using an exposure device (Trendsetter F, manufactured by Kodak). (Rotational speed: 185 rpm).
For evaluation of development residue, the entire surface was exposed to produce a clear image.
(Development process)
The exposed lithographic printing plate precursor is an automatic development processor shown in FIG. 1 [developing tank 25L, plate conveyance speed 100 cm / min, brush having an outer diameter of 50 mm in which polybutylene terephthalate fibers (hair diameter 200 μm, hair length 17 mm) are implanted. One roll is processed at a temperature of 30 ° C. using the developer shown in Table 1 at 200 revolutions per minute in the same direction as the conveying direction (peripheral speed 0.52 m / sec at the tip of the brush, drying temperature 80 ° C.). Development processing was performed until the amount reached 20 m ² / L.

(Specific developer 1)
8963.8 g of water
Sodium carbonate 200g
Sodium bicarbonate 100g
New call B4SN (61% aqueous solution) 656g
(Polyoxyethylene naphthyl ether sulfate, anionic surfactant manufactured by Nippon Emulsifier Co., Ltd.)
EDTA 4Na 80g
2-Bromo-2-nitropropane-1,3-diol 0.1 g
2-Methyl-4-isothiazolin-3-one 0.1 g
(PH: 9.7)

(Specific developer 2)
8665g of water
150g potassium carbonate
Potassium bicarbonate 80g
ELEMINOL MON (47% aqueous solution) 745g
(Sodium dodecyl diphenyl ether disulfonate, anionic surfactant manufactured by Sanyo Chemical Co., Ltd.)
180g primary ammonium phosphate
180 g of sodium hexametaphosphate
(PH: 9.7)

(Specific developer 3)
8150.8g of water
Sodium carbonate 200g
Sodium bicarbonate 80g
Perex NBL (35% aqueous solution) 1429g
(Sodium alkylnaphthalene sulfonate, anionic surfactant manufactured by Kao Corporation)
Citric acid 40g
20g of primary ammonium phosphate
80g of propylene glycol
2-Bromo-2-nitropropane-1,3-diol 0.1 g
2-Methyl-4-isothiazolin-3-one 0.1 g
(PH: 9.8)

(Comparative developer 1)
9779.8 g of water
Sodium carbonate 130g
Sodium bicarbonate 70g
20g of primary ammonium phosphate
2-Bromo-2-nitropropane-1,3-diol 0.1 g
2-Methyl-4-isothiazolin-3-one 0.1 g
(PH: 9.7)

[Evaluation of development residue]
The entire exposed lithographic printing plate precursor for developing debris evaluation was developed by an automatic developing machine, and the number of debris adhering to the plate was visually measured after the developing process. The results are shown in Table 1 below. The unit is [pieces / m ² ].

(Developability evaluation)
The lithographic printing plate obtained by imagewise exposure and then development is attached to a printing machine SOR-M manufactured by Heidelberg, and dampening solution (EU-3 (Etchi solution manufactured by FUJIFILM Corporation) / water / Using isopropyl alcohol = 1/89/10 (volume ratio)) and Fusion G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.), printing was performed at a printing speed of 6000 sheets per hour. At this time, it was confirmed whether or not scumming occurred in the non-image area of the printed matter obtained.

From the results of Table 1, according to the lithographic printing plate production method of the present invention, despite the one-bath treatment with a weak alkaline developer, the generation of debris in the developing tank is suppressed, and the developability is excellent. Since no background stains due to the remaining film in the non-image area were observed, it can be seen that a high-quality printed material can be obtained by the planographic printing plate obtained by the production method of the present invention.
On the other hand, in Comparative Examples 1 and 2 that do not contain a specific alkali-soluble resin, and in Comparative Example 3 that uses a developer outside the scope of the present invention, development debris is observed, and scumming of non-image areas is also observed. The developability was inferior to that of the examples.

4 Planographic printing plate precursor 6 Developing unit 10 Drying unit 16 Transport roller 20 Developing tank 22 Transport roller 24 Brush roller 26 Squeeze roller 28 Backup roller 36 Guide roller 38 Skewer roller

Claims (6)

  A positive type comprising, on a support, an image recording layer containing (A) an alkali-soluble resin having a urea bond and a phenolic hydroxyl group in the side chain; and (B) a compound that absorbs light and generates heat. An exposure process for image exposure of the lithographic printing plate precursor, and a development process for developing the image-exposed positive lithographic printing plate precursor using an alkaline aqueous solution having a pH of 8.5 to 10.8 containing an anionic surfactant. The preparation method of the lithographic printing plate which contains in this order.   The method for producing a lithographic printing plate according to claim 1, wherein the alkali-soluble resin is a polymer containing a monomer having a urea bond and a phenolic hydroxyl group as a polymerization component.   3. The copolymer according to claim 2, wherein the polymer is a copolymer containing, as polymerization components, a monomer having the urea bond and a phenolic hydroxyl group, and an N-phenylmaleimide derivative or an acrylic monomer having a sulfonamide group in the side chain. A method for producing the described lithographic printing plate.   The method for preparing a lithographic printing plate according to any one of claims 1 to 3, wherein a content of the water-soluble polymer compound in the alkaline aqueous solution is 10 ppm or less.   A lower image recording layer comprising: (A) an alkali-soluble resin having a urea bond and a phenolic hydroxyl group in the side chain; and (B) a compound that absorbs light and generates heat, and The method for producing a lithographic printing plate according to any one of claims 1 to 4, wherein the image recording layer comprises an upper image recording layer formed on the lower image recording layer and containing an alkali-soluble resin. .   The method for preparing a lithographic printing plate according to any one of claims 1 to 5, wherein the developing step is a one-bath treatment with an alkaline aqueous solution.