JP2012230194A - Photosensitive composition and lithographic printing plate precursor - Google Patents

Abstract

で表される繰り返し単位を少なくとも含有し、式（Ｉ）、（ＩＩ）および（ＩＩＩ）で表される繰り返し単位の含有量が、それぞれ３〜２０質量％、１５〜４５質量％、および１５〜３５質量％であるアルカリ可溶性樹脂を少なくとも含有する感光性組成物。
【選択図】なしA photosensitive composition, a lithographic printing plate precursor for a thermal negative plate, and an image forming method capable of forming a photosensitive layer capable of one-liquid processing and having excellent printing durability.
The following formulas (I) to (III)

Containing at least repeating units represented by formulas (I), (II) and (III), the contents of the repeating units are 3 to 20% by mass, 15 to 45% by mass, and 15 to 15%, respectively. A photosensitive composition containing at least an alkali-soluble resin of 35% by mass.
[Selection figure] None

Description

  The present invention relates to a photosensitive composition and a lithographic printing plate precursor using the same. In particular, the present invention relates to a negative lithographic printing plate precursor for so-called direct plate making which can be directly made from a digital signal of a computer or the like.

  Conventionally, as a lithographic printing plate precursor, one having a constitution in which a lipophilic photosensitive resin layer is provided on a hydrophilic support is widely used. As the plate making method, usually, a method of obtaining a desired printing plate by dissolving and removing a non-image area with an alkaline developer or an organic solvent after mask exposure through a lithographic film has been used.

  Recently, digitization technology that electronically processes, stores, and outputs image information using a computer has become widespread. Various new image output methods corresponding to such digitization technology have come into practical use. As a result, computer-to-plate (CTP) technology that scans highly directional light such as laser light according to digitized image information and directly produces a printing plate without going through a lithographic film is eagerly desired. Therefore, obtaining a lithographic printing plate precursor adapted to this is an important technical issue.

Such lithographic printing plate precursors capable of scanning exposure are disclosed in Patent Documents 1 to 4. According to these documents, a configuration in which a photosensitive layer containing a photosensitive composition capable of generating active species such as radicals by laser exposure on a hydrophilic support is proposed and put on the market. This lithographic printing plate precursor is subjected to laser scanning exposure based on digital information to generate active species, which causes the photosensitive layer to undergo physical or chemical changes to insolubilize it, and subsequently develop the negative lithographic printing. You can get a version.

JP 2005-257828 A JP 2007-262125 A JP 2009-86514 A JP 2009-25683 A

However, the conventional development processing step consists of three steps of processing with an alkaline developer having a pH of 11 or more, pouring an alkaline agent in a washing bath, and then processing with a gum solution mainly composed of a hydrophilic resin. There have been problems in terms of environment and running cost, such as the problem of processing of developing waste liquid, washing waste liquid, and gum waste liquid. Thus, from the viewpoint of simplification of plate making work and protection of the global environment, a drastic reduction of processing solutions including development processing steps has been strongly desired. For this reason, it has found great utility in producing a lithographic printing plate in a one-liquid process that combines the conventional development process and gumming process.

  Accordingly, an object of the present invention is to provide a photosensitive composition capable of forming a photosensitive layer capable of one-liquid processing and having excellent printing durability, and a lithographic printing plate precursor for a thermal negative plate provided with the photosensitive layer. And an image forming method using the planographic printing plate precursor.

（式中、Ｒ^１、Ｒ^２、Ｒ^３は、独立して水素原子又は置換基を有してもよい炭素数１〜１０のアルキル基を示し、Ｌは１〜１０の整数を示す。）
で表される繰り返し単位を少なくとも含有し、式（Ｉ）で表される繰り返し単位の含有量が３質量％〜２０質量％、式（ＩＩ）で表される繰り返し単位の含有量が１５質量％〜４５質量％、式（ＩＩＩ）で表される繰り返し単位の含有量が１５質量％〜３５質量％であるアルカリ可溶性樹脂と、
下記式（ＩＶ）

（式中、Ｒ^４〜Ｒ^６は、独立して水素原子、又は置換基を有してもよいアルキル基もしくはアルコキシ基を示し、Ｘは、エステル結合、アミド結合又はフェニル基を示し、Ｚは、０又は１を示し、Ｙは、０〜１０の整数を示す。）
で表わされるシランカップリング剤と、
赤外線吸収剤と、
ラジカル重合性開始剤と、
エチレン性二重結合を有する重合性化合物と
を少なくとも含有する感光性組成物を提供する。
本発明は、別の側面で、支持体と、上記感光性組成物を用いて前記支持体上に形成された感光層とを備えるネガ型平版印刷版原版を提供する。
本発明は、別の側面で、上記ネガ型平版印刷版原版を、赤外線レーザーで画像露光する工程と、画像露光された前記感光層を、ナトリウム塩と、界面活性剤と、水溶性カチオン化澱粉とを少なくとも含有するｐＨが８〜１１の弱アルカリ性現像液を用いて現像する工程とを少なくとも含む画像形成方法を提供する。 The present invention is a photosensitive composition comprising the following formulas (I) to (III):

(In formula, R < ¹ >, R < ² >, R < ³ > shows the C1-C10 alkyl group which may have a hydrogen atom or a substituent independently, and L shows the integer of 1-10.)
The content of the repeating unit represented by formula (I) is 3% by mass to 20% by mass, and the content of the repeating unit represented by formula (II) is 15% by mass. An alkali-soluble resin having a content of the repeating unit represented by the formula (III) of 15 to 35% by mass;
Formula (IV) below

(In the formula, R ^{4 to} R ⁶ independently represent a hydrogen atom, or an alkyl group or an alkoxy group which may have a substituent, X represents an ester bond, an amide bond or a phenyl group, and Z represents , 0 or 1, and Y represents an integer of 0 to 10.)
A silane coupling agent represented by:
An infrared absorber;
A radical polymerizable initiator;
Provided is a photosensitive composition containing at least a polymerizable compound having an ethylenic double bond.
In another aspect, the present invention provides a negative lithographic printing plate precursor comprising a support and a photosensitive layer formed on the support using the photosensitive composition.
According to another aspect of the present invention, the negative lithographic printing plate precursor is image-exposed with an infrared laser, the image-exposed photosensitive layer is coated with a sodium salt, a surfactant, and a water-soluble cationized starch. And an image forming method including at least a step of developing using a weak alkaline developer having a pH of 8 to 11 containing at least.

  The photosensitive layer formed using the photosensitive composition according to the present invention can be developed by one-liquid processing, and can provide a high-quality printing plate excellent in developability, printing durability, and chemical resistance. .

  Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments.

[Photosensitive composition]
The photosensitive composition according to the present invention contains an alkali-soluble resin, a silane coupling agent, an infrared absorber, a radical polymerizable initiator, and a polymerizable compound having an ethylenic double bond.

式中、Ｒ^１、Ｒ^２、Ｒ^３は、独立して水素原子又は置換基を有してもよい炭素数１〜１０、好ましくは１〜４のアルキル基を示す。また、Ｌは１〜１０の整数を示す。置換基は、例えば、メチル基、エチル基、ブチル基等である。 (A) Alkali-soluble resin The alkali-soluble resin contained in the photosensitive composition of the present invention represents a repeating unit represented by the following formula (I) of 3% by mass to 20% by mass and represented by the following formula (II). 15% to 45% by mass of the repeating unit and 15% to 35% by mass of the repeating unit represented by the following formula (III). A resin having such a composition becomes alkali-soluble.

In formula, R < ¹ >, R < ² >, R < ³ > shows the C1-C10, preferably 1-4 alkyl group which may have a hydrogen atom or a substituent independently. L represents an integer of 1 to 10. Examples of the substituent include a methyl group, an ethyl group, and a butyl group.

  Monomers that give repeating units represented by formulas (I) to (III) can be synthesized using conventional synthesis methods. About the manufacturing method of alkali-soluble resin, a desired copolymer can be obtained by melt | dissolving each monomer component in a solvent, adding a radical polymerization initiator, and heating and polymerizing as needed, for example. Half of the monomer may be polymerized first, and the remaining half may be added later for polymerization. The heating temperature can be, for example, 50 to 150 ° C. The copolymer thus obtained has a polystyrene calculated weight average molecular weight of 10,000 to 150,000, preferably 10,000 to 100,000, as measured by gel permeation chromatography (GPC). If the weight average molecular weight is less than 10,000, the image portion is likely to swell and mechanical strength may be insufficient. If it exceeds 150,000, stains due to poor development may easily occur.

  Examples of the solvent used for the polymerization of the alkali-soluble resin include methyl cellosolve, propylene glycol monomethyl ether, dioxane, methyl ethyl ketone, cyclohexanone, N, N-dimethylformamide, N, N-dimethylacetamide and the like. The amount of the solvent added is, for example, 1.0 to 5.0 times the mass of the total amount of monomers. Examples of the radical polymerization initiator used for the alkali-soluble resin include 2,2′-azobis (2-methylbutyronitrile), benzoyl peroxide, and the like. The addition amount of the radical polymerization initiator is, for example, 0.1 to 3.0% by mass with respect to the total amount of monomers.

Examples of other monomers having a polymerizable unsaturated bond group that are added to the monomer that gives the repeating unit represented by formulas (I) to (III) as necessary include the monomers listed in (1) to (10) below. Is desirable.
(1) A monomer having a phenolic hydroxyl group. For example, N- (4-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) methacrylamide, p-isopropenylphenol, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxy Phenyl methacrylate, m-hydroxyphenyl methacrylate, and p-hydroxyphenyl methacrylate.
(2) A monomer having a sulfonamide group. For example, m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide.
(3) A monomer having an active imide group. For example, N- (p-toluenesulfonyl) methacrylamide and N- (p-toluenesulfonyl) acrylamide.
(4) A monomer having an aliphatic hydroxyl group. For example, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxy-3-phenoxypropyl methacrylate.
(5) α, β-unsaturated carboxylic acid. For example, acrylic acid, methacrylic acid, and maleic anhydride.
(6) A monomer having an allyl group. For example, allyl methacrylate and N-allyl methacrylamide.
(7) Alkyl acrylates or alkyl methacrylates. For example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, lauryl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, They are butyl methacrylate, amyl methacrylate, hexyl methacrylate, octyl methacrylate, lauryl methacrylate, and glycidyl methacrylate.
(8) Acrylamides or methacrylamides. For example, acrylamide, N-methylol acrylamide, N-ethyl acrylamide, N-hexyl acrylamide, N-cyclohexyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, methacrylamide, N-methylol methacrylamide, N-ethyl Methacrylamide, N-hexylmethacrylamide, N-cyclohexylmethacrylamide, N-hydroxyethylmethacrylamide, N-phenylmethacrylamide.
(9) Styrenes. For example, styrene, α-methylstyrene, chloromethylstyrene and the like.
(10) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile and the like.
One of these compounds may be added alone, two or more of the same group of compounds in (1) to (10) may be added in combination, or two or more of the compounds in different groups may be combined. May be added. The content of other monomers added as necessary in the alkali-soluble resin is preferably 1 to 67% by mass, preferably 5 to 20% by mass, based on the total amount of monomers constituting the alkali-soluble resin.

  The alkali-soluble resin preferably contains a repeating unit derived from the monomer (5) among the monomers (1) to (10), and the side chain carboxyl group of the repeating unit has a polymerizable second group. It is particularly preferred to contain a material into which a heavy bond site has been introduced. For example, a polymerizable double bond can be introduced at the terminal by addition reaction of glycidyl methacrylate with the side chain carboxyl group of the repeating unit derived from the monomer (5). The compound capable of introducing a double bond is not limited to glycidyl methacrylate, and may be 2- (2-vinyloxyethoxy) ethyl acrylate, 2- (2-vinyloxyethoxy) ethyl methacrylate, or the like. By introducing a polymerizable double bond site at the end of the side chain carboxyl group, a stronger photosensitive layer can be obtained. The repeating unit derived from the monomer (5) preferably occupies 1 to 67% by mass in the total mass of the alkali-soluble resin.

  Further, the introduction rate of the double bond site by addition of glycidyl methacrylate or the like is preferably 20 to 70%, more preferably 30 to 60% with respect to the carboxyl group in the alkali-soluble resin. The introduction rate of the double bond site can be adjusted by the reaction temperature and reaction time. When the introduction rate is less than 20%, the sensitivity may be remarkably lowered, and when the introduction rate exceeds 70%, the developability may be deteriorated.

The alkali-soluble resin of the present invention may be used alone or in combination of two or more. The content of the alkali-soluble resin containing the repeating unit represented by the above formulas (I) to (III) is preferably 10 to 40% by mass, more preferably 10 to 30% with respect to the total mass of the photosensitive composition. % By mass. When it is 10% by mass or more, printing durability and chemical resistance are particularly improved. On the other hand, if it is less than 10% by mass, the developability may deteriorate.

  The photosensitive composition of this invention may contain another alkali-soluble resin with the alkali-soluble resin containing the repeating unit represented by Formula (I)-(III). Another alkali-soluble resin is preferably a copolymer of an acrylic acid derivative. The copolymer of acrylic acid derivative is an acrylic acid copolymer having a side chain carboxyl group, and a compound capable of introducing a double bond into the carboxyl group is subjected to an addition reaction to form a polymerizable double bond at the terminal. Particularly preferred are those having Here, the acrylic acid derivative includes not only acrylic acid but also a compound derived from methacrylic acid. Examples of the compound capable of introducing a double bond include glycidyl methacrylate, 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, 1,1-bis (acryloyloxymethyl) ethyl isocyanate, and the like. It is not limited to. The introduction rate of the double bond site is preferably 20 to 70%, more preferably 30 to 60% with respect to the carboxyl group in the acrylic acid derivative copolymer. The content of the acrylic acid copolymer is preferably 5.0 to 20% by mass with respect to the total mass of the photosensitive composition.

  The polystyrene calculated weight average molecular weight (Mw) by GPC measurement of the copolymer of acrylic acid derivative is preferably 5,000 to 150,000, particularly preferably 10,000 to 100,000. When the Mw is 1,000 or more, particularly 10,000 or more, a particularly sufficient coating film is obtained. When the Mw is 150,000 or less, particularly 100,000 or less, the solubility of the exposed portion in the alkaline developer is improved, and particularly good. Can be developed.

該シランカップリング剤は、例えば、トリクロロシランにアリルエーテル化合物を付加反応させ、アルコキシ化させることによって合成できる。これら化合物は、信越化学工業社、東レ・ダウコーニング社、Ｇｅｌｅｓｔ社、チッソ社等から市販されている。上記式（ＩＶ）におけるＲ^４、Ｒ^５およびＲ^６は、同一又は異なり、水素原子、又は置換基を有してもよい好ましくは炭素数１〜１０のアルキル基もしくはアルコキシ基を示す。Ｒ^４、Ｒ^５およびＲ^６のいずれかがアルコキシ基である場合、その炭素数は、好ましくは１〜３である。置換基は、例えば、メチル基、エチル基、ブチル基である。上記式（ＩＶ）におけるＸは、エステル結合、アミド結合又はフェニル基を示す。Ｚは、０又は１を示す。Ｙは、０〜１０の整数を示す。より好ましくは、０〜５である。 (B) Silane coupling agent The silane coupling agent used in the photosensitive composition of this invention is represented by Formula (IV).

The silane coupling agent can be synthesized, for example, by subjecting trichlorosilane to an addition reaction of an allyl ether compound and alkoxylation. These compounds are commercially available from Shin-Etsu Chemical Co., Toray Dow Corning, Gelest, Chisso, and the like. R ⁴ , R ⁵ and R ⁶ in the above formula (IV) are the same or different and each represents a hydrogen atom or an optionally substituted alkyl group or alkoxy group which may have a substituent. When any of R ⁴ , R ⁵ and R ⁶ is an alkoxy group, the carbon number is preferably 1 to 3. The substituent is, for example, a methyl group, an ethyl group, or a butyl group. X in the above formula (IV) represents an ester bond, an amide bond or a phenyl group. Z represents 0 or 1. Y represents an integer of 0 to 10. More preferably, it is 0-5.

  The content of the silane coupling agent represented by the formula (IV) is preferably 15 to 40% by mass, more preferably 20 to 40% by mass with respect to the total mass of the photosensitive composition. When the content is 15% by mass or more, printing durability and chemical resistance are particularly improved. On the other hand, if it is less than 15% by mass, the printing durability and chemical resistance deteriorate.

(C) Infrared Absorber The infrared absorber used in the photosensitive composition of the present invention is not particularly limited as long as it is a compound that can absorb light from an image exposure light source and convert the energy into heat. An infrared absorbing dye having an absorption maximum in the range of 650 to 1300 nm, preferably having an absorption maximum and a molar extinction coefficient ε of 10 ⁵ or more is particularly effective. The infrared absorbent is used to promote the generation of radicals by causing heat or photoelectron transfer generated from the infrared absorbent upon irradiation with light. For this reason, the photosensitive composition of this invention becomes a negative photosensitive layer with which the solubility with respect to an alkaline developing solution reduces by laser exposure by containing an infrared absorber.

  Examples of the infrared absorber include cyanine dyes, squalium dyes, croconium dyes, azurenium dyes, phthalocyanine dyes, naphthalocyanine dyes, polymethine dyes, naphthoquinone dyes, thiopyrylium dyes, dithiol metal complex dyes, Anthraquinone dyes, indoaniline metal complex dyes, intermolecular CT dyes and the like are preferable.

  Although these pigment | dyes can be synthesize | combined by a well-known method, a commercial item can also be used. These dyes are commercially available from companies such as Nippon Kayaku Co., Ltd., DIC Co., Ltd., Yamamoto Kasei Co., Ltd., Hayashibara Co., Ltd., Mitsui Chemicals, Showa Denko Co., Ltd., and Fuji Film Co., Ltd.

  The addition amount of the said infrared absorber is 0.5-10 mass% with respect to the gross mass of the photosensitive composition, Preferably it is 0.6-8.0 mass%. When the addition amount is 0.5% by mass or more, particularly 0.6% by mass or more, the sensitivity is particularly high, and when it is 10% by mass or less, particularly 8.0% by mass or less, the developability of the non-image area (unexposed area). Is particularly preferable since it improves.

(D) Radical polymerizable initiator A known compound can be used as the radical polymerizable initiator. For example, organic boron salts, trihaloalkyl-substituted compounds, hexaarylbisimidazoles, titanocene compounds, ketoxime compounds, thio compounds, organic peroxides, onium salts (iodonium salts and diazonium salts described in JP-A-2003-114532) , Sulfonium salts) and the like. Among these radical polymerizable initiators, organic boron salts and onium salts are particularly preferably used. More preferably, an organic boron salt and an onium salt are used in combination.

  The content of the radical polymerizable initiator as described above is preferably in the range of 1 to 40% by mass, and in the range of 1 to 20% by mass, with respect to the polymerizable compound having an ethylenic double bond. Further preferred.

(E) Polymerizable compound having an ethylenic double bond Known compounds can be used as the polymerizable compound having an ethylenic double bond. By containing the polymerizable compound, it is considered that the film strength is improved, the sensitivity is high, the adhesiveness with the support is excellent, and the printing durability is also improved.

  As the polymerizable compound having an ethylenic double bond, various compounds from monomers having a molecular weight of 1000 or less to oligomers having a molecular weight of 1000 or more and those having a polymer region can be used. Examples of such compounds include esters of unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.) and aliphatic polyhydric alcohol compounds, unsaturated carboxylic acids and aliphatic polyhydric compounds. Examples thereof include amides with polyvalent amine compounds, urethanes with unsaturated alcohols and isocyanate compounds, esters with unsaturated carboxylic acids and epoxy compounds, and the like.

  More specifically, for example, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, triethylene glycol diacrylate, triethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, butylene glycol. Dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, neopentyldiol diacrylate, neopentyldiol dimethacrylate, polypropylene glycol diacrylate, methoxydiethylene glycol methacrylate, methoxytetraethylene glycol methacrylate, methoxypolyethylene glycol methacrylate Relate, trimethylolpropane trimethacrylate, pentaerythritol diacrylate, pentaerythritol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol hexaacrylate.

  The polymerizable compound having an ethylenic double bond can be synthesized by a known method, or a commercially available compound can be used. For example, it is commercially available from Toa Gosei Co., Ltd., NOF Co., Ltd., Kyoeisha Chemical Co., Ltd., Shin-Nakamura Chemical Co., Ltd., Mitsubishi Chemical Co., Nippon Kayaku Co., Ltd., Osaka Organic Chemical Co., Ltd.

  The addition amount of the polymerizable compound having an ethylenic double bond is preferably 1 to 40% by mass with respect to the total mass of the photosensitive composition (that is, based on the total solid content of the photosensitive composition), and Preferably it is 2-30 mass%. When the addition amount is 1% by mass or more, the sensitivity becomes faster, and when it is 40% by mass or less, the scratch resistance of the image part (exposure part) is further improved, which is preferable.

(F) Other additives The photosensitive composition of the present invention is a colorant, a leuco dye, a grease-sensitive resin, or a polymerization inhibitor, if necessary, as long as the effects of the present invention are not impaired in addition to the above components. Further, a surfactant, a plasticizer and the like can be further added.

  In the photosensitive composition of the present invention, a colorant can be used in order to make the image easy to see. As the colorant, oil-soluble dyes and basic dyes are preferable. Specifically, Crystal Violet, Malachite Green, Victoria Blue, Methylene Blue, Ethyl Violet, Rhodamine B, Victoria Pure Blue BOH (Hodogaya Chemical Industries), Oil Blue 613 (Orient Chemical Industries), Oil Green, etc. Can be mentioned. The addition amount of these dyes is preferably 0.05 to 5.0% by mass, more preferably 0.1 to 4.0% by mass in the photosensitive composition. If it is 0.05% by mass or more, particularly 0.1% by mass or more, the photosensitive layer is sufficiently colored and the image is particularly easy to see. If it is 5.0% by mass or less, particularly 4.0% by mass or less, a non-image after development. The remainder of the dye is difficult to remain in the part, which is preferable.

  A leuco dye can be added to the photosensitive composition of the present invention for the purpose of coloring the photosensitive layer and suppressing dissolution in the developer. As the leuco dye, a dye containing a lactone ring used in conventional heat-sensitive recording materials is preferable. Preferred examples include 3,3-bis (p-dimethylaminophenyl) phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 3,3- Bis (p-dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3,3- Bis (p-diethylamino-2-ethoxyphenyl) -4-azaphthalide, 3,6-dimethoxyfluorane, 3-cyclohexylamino-6-chlorofluorane, 3- (N, N-diethylamino) -5-methyl-7 -(N, N-dibenzylamino) fluorane, 3-dimethylamino-5, 7-dimethylfluorane, 3 Dimethylamino-7-methylfluorane, 3-diethylamino-7, 8-benzfluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7-chloroaminofluorane, 3-pyrrolidino- 6-methyl-7-anilinofluorane, 3-dimethylamino-6-methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 2- (N- (3 '-Trifluoromethylphenyl) amino) -6-diethylaminofluorane, 2- (3,6-bis (diethylamino) -9- (o-chloroanilino) xanthylbenzoate lactam) and the like.

  Content of a leuco pigment | dye is 0.01-10 mass% in a photosensitive composition, Preferably it is 0.05-5 mass%. When the content is 0.01% by mass or more, particularly 0.05% by mass or more, the photosensitive layer is sufficiently colored, and the visibility is excellent. When the content is 10% by mass or less, particularly 5% by mass or less, the non-image area (unexposed) Part) is particularly preferred since the developability is particularly improved.

  Furthermore, in the photosensitive composition of this invention, in order to improve the fat sensitivity (lipophilicity) of a photosensitive layer, a fat sensitive resin can be added. Examples of the fat-sensitive resin include condensates of phenols and aldehydes substituted with an alkyl group having 3 to 15 carbon atoms, or t-butylphenol formaldehyde resin as described in JP-A No. 50-125806. Etc. can be used. The ratio of the above-mentioned oil-sensitive resin to the total mass of the photosensitive composition is preferably 0.01 to 10% by mass, and more preferably 0.05 to 10% by mass.

In the photosensitive composition of the present invention, a compound having a polymerizable ethylenically unsaturated double bond, that is, a small amount of a thermal polymerization inhibitor may be added in order to prevent unnecessary thermal polymerization of the polymerizable compound. desirable. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4-thiobis (3-methyl-6-t-butylphenol ), 2,2-methylenebis (4-methyl-6-tert-butylphenol), N-nitrosophenylhydroxyamine primary cerium salt and the like. The amount of the thermal polymerization inhibitor added is preferably about 0.01% by mass to about 5% by mass with respect to the total solid content in the photosensitive composition.
If necessary, in order to prevent polymerization inhibition by oxygen, higher fatty acid derivatives such as behenic acid and behenamide are added and unevenly distributed on the surface of the layer in the process of drying after coating. Also good. The addition amount of the higher fatty acid derivative is preferably about 0.5% by mass to about 10% by mass with respect to the total solid content in the photosensitive composition.

  The photosensitive composition of the present invention is described in Japanese Patent Application Laid-Open Nos. 62-251740, 3-208514, and Japanese Patent Application No. 2006-241033 in order to broaden the processing stability against development conditions. Nonionic surfactants such as those described in JP-A-59-121044 and JP-A-4-13149 can be added. Preferable examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether, fluorine surfactant and the like. Preferred examples of the amphoteric surfactant include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, and N-tetradecyl-N, N- Examples include betaine type (for example, trade name “Amorgen K”: manufactured by Daiichi Kogyo Co., Ltd.). The proportion of the nonionic surfactant and the amphoteric surfactant in the photosensitive composition is preferably 0.01 to 15% by mass, and more preferably 0.01 to 10% by mass. When the content is 0.01% by mass or more, the developability is particularly good, and when it exceeds 15% by mass, the strength of the image area may be weakened.

  A plasticizer can also be added to the photosensitive composition of the present invention in order to impart flexibility and the like of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, trioctyl phosphate, tributyl phosphate and the like are used. The proportion of the plasticizer in the photosensitive composition is preferably 0.01 to 10% by mass, and more preferably 0.05 to 10% by mass.

[Negative lithographic printing plate]
A negative lithographic printing plate in which a photosensitive layer containing the photosensitive composition is provided on a support is also one aspect of the present invention. According to the negative lithographic printing plate precursor provided with a photosensitive layer, an unsaturated double bond of a polymerizable compound having an unsaturated double bond site and an ethylenic double bond in the silane coupling agent upon irradiation with an infrared laser. A very high density cross-linked structure is obtained by high-speed polymerization with the site. On the other hand, the silyl group site in the silane coupling agent is considered to self-condense during coating of the photosensitive layer, causing a complicated structural change, and a stronger photosensitive layer is generated by the interaction between these inorganic compounds in the photosensitive layer. . Further, the alkali-soluble resin of the present invention contains recurring units represented by structural formulas (I), (II), and (III) in a specific range, so that developability at pH 8 to 11 and strong resistance. Printing performance was made possible.
The lithographic printing plate precursor according to the invention can be usually produced by dissolving the above-described components of the photosensitive composition in a solvent to form a photosensitive solution and coating the photosensitive solution on a suitable support. Solvents used here include methanol, ethanol, propanol, methylene chloride, ethyl acetate, tetrahydrofuran, propylene glycol monomethyl ether, propylene glycol monoethyl ether, methyl cellosolve, ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, dimethyl Examples include, but are not limited to, formamide, dimethyl sulfoxide, dioxane, dioxolane, acetone, cyclohexanone, trichloroethylene, methyl ethyl ketone, and γ-butyl lactone. These solvents are used alone or in combination of two or more. The concentration of the components (total solid content including additives) of the photosensitive composition in the photosensitive solution is preferably 1 to 50% by mass.

Various methods can be used as the coating method, and examples thereof include spin coating, extrusion coating, bar coater coating, roll coating, air knife coating, dip coating, and curtain coating. The coating amount of the photosensitive layer varies depending on the use, but is preferably 0.5 to 5.0 g / m ² when dried. The thickness of the photosensitive layer after drying is, for example, 0.5 to 5.0 μm.

  Examples of the support include a metal plate such as aluminum, zinc, copper, or steel, a metal plate plated or vapor-deposited with chromium, zinc, copper, nickel, aluminum, iron, or the like, paper, plastic film, or glass. Examples thereof include a plate, paper coated with a resin, and a plastic film subjected to a hydrophilic treatment.

  As the above-mentioned support, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Thus, the composition of the aluminum plate applied to the present invention is not specified, and conventionally known and used aluminum plates can be appropriately used. The thickness of the aluminum plate used in the present invention is approximately 0.1 to 0.5 mm, preferably 0.12 to 0.4 mm.

  Prior to roughening the aluminum plate, a degreasing treatment with, for example, a surfactant or an alkaline aqueous solution for removing rolling oil on the surface is performed. The surface roughening treatment of the aluminum plate is performed by various methods. For example, a method of mechanically roughening, a method of electrochemically roughening the surface, and a method of selectively dissolving the surface chemically. By the method. As the mechanical method, known methods such as brush polishing, ball polishing, blast polishing, and buff polishing 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, a method combining a mechanical method and an electrochemical method disclosed in JP-A-53-123204 can also be used. The roughened aluminum plate is subjected to an alkali etching treatment and neutralization treatment as necessary, and then subjected to an anodization treatment to enhance the water retention and wear resistance of the surface as desired. As the electrolyte used for anodizing the aluminum plate, sulfuric acid, phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is generally used.

The treatment conditions for anodization vary depending on the electrolyte used and thus cannot be specified in general. In general, however, the electrolyte concentration is 1 to 60% by mass solution, the liquid temperature is 5 to 60 ° C., and the current density is 2 to 50 A / day. dm ² , voltage 1 to 100 V, and electrolysis time 5 seconds to 3 minutes are suitable. If the amount of anodic oxide film is 0.5 to 5.0 g / ^{m 2} is suitable, wear resistance is especially good at 0.5 g / ^{m 2} or more, the 5.0 g / ^{m 2} or less, the pores of the anodic oxidation Dyes and the like are particularly preferred because they are difficult to penetrate.

  After the anodization, the aluminum plate is further subjected to a chemical conversion treatment with, for example, an alkali silicate, sodium phosphate, sodium fluoride, zirconium fluoride, alkyl titanate, trihydroxybenzoic acid alone or in a mixed solution, Sealing treatment by immersion in an aqueous solution or steam bath, coating treatment with an aqueous solution such as strontium acetate, zinc acetate, magnesium acetate, or calcium benzoate, polyvinylpyrrolidone, polyaminesulfonic acid, polyvinylphosphonic acid, polyacrylic acid, Alternatively, chemical conversion or coating treatment of the front or back surface with polymethacrylic acid or the like can be performed as a post-treatment.

  Furthermore, as the above-mentioned support, an aluminum support subjected to the surface treatment described in JP-A-10-297130 can be used.

  The lithographic printing plate precursor according to the invention comprises a photosensitive layer containing the photosensitive composition on a support and a protective layer on the photosensitive layer. The photosensitive layer of the lithographic printing plate precursor according to the present invention is a photopolymerizable negative photosensitive layer. Usually, in order to perform exposure in the air, a photosensitive layer of a low molecular compound such as oxygen or a basic substance existing in the air is used. For the purpose of preventing mixing into the layer, it is preferable to provide a water-soluble protective layer on the photosensitive layer. This is because these low molecular weight compounds inhibit an image forming reaction caused by exposure in the photosensitive layer. The water-soluble protective layer in the present invention requires low permeability of low-molecular compounds such as oxygen, and further does not substantially inhibit the transmission of light used for exposure, has excellent adhesion with the image recording layer, and It is desirable that it can be easily removed in the development process after exposure. Such a device relating to the protective layer has been conventionally made, and is described in detail in US Pat. No. 3,458,311 and JP-B-55-49729. As a material that can be used for the protective layer, for example, a water-soluble compound having relatively excellent crystallinity is preferably used. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, acidic celluloses, gelatin, gum arabic, polyacrylic acid Among these, water-soluble polymers such as those described above are known, but among these, the use of polyvinyl alcohol (PVA) as the main component gives the best results in terms of basic properties such as oxygen barrier properties and development removability.

The components of the protective layer (selection of PVA type, use of additives), coating amount, and the like are selected in consideration of fogging, adhesion, and scratch resistance in addition to oxygen barrier properties and development removability. In general, the higher the hydrolysis rate of the PVA used (the higher the content of the unsubstituted vinyl alcohol unit in the protective layer), the higher the film thickness, the higher the oxygen barrier property and the more advantageous in terms of sensitivity. However, when the oxygen barrier property is extremely increased, there arises a problem that unnecessary polymerization reaction occurs during production and raw storage, and unnecessary fogging and image line thickening occur during image exposure. In addition, adhesion to the image area and scratch resistance are extremely important in handling the plate. That is, when a hydrophilic layer made of a water-soluble polymer is laminated on an oleophilic photosensitive layer, film peeling due to insufficient adhesive force is likely to occur, and the peeled part causes defects such as poor film hardening due to inhibition of oxygen polymerization. On the other hand, various proposals have been made to improve the adhesion between these two layers. For example, US Patent Application No. 292501 and US Patent Application No. 44563 include an acrylic emulsion or a water-insoluble vinylpyrrolidone-vinyl acetate copolymer in a hydrophilic polymer mainly composed of polyvinyl alcohol. It is described that sufficient adhesiveness can be obtained by mixing 20 to 60% by mass and the like and laminating on the photosensitive layer. Any of these known techniques can be applied to the photosensitive layer composition of the present invention. Such a coating method of the protective layer is described in detail in, for example, US Pat. No. 3,458,311 and JP-B-55-49729. In the photosensitive composition of the present invention, polyvinyl alcohol and polyvinyl pyrrolidone are preferably used in combination from the viewpoints of adhesive strength, sensitivity, and unnecessary fog. The addition ratio (mass ratio) is preferably such that the ratio of polyvinyl alcohol: polyvinylpyrrolidone is 3: 1 or less, that is, the mixing ratio of PVP to PVA is 1/3 or less. The coating mass after drying the water-soluble protective layer is preferably 1.0 to 3.0 g / m ² . The thickness of the protective layer is, for example, 1.0 to 3.0 μm.

  The lithographic printing plate precursor according to the invention is not necessarily required to be adjacent to the photosensitive layer and the protective layer as long as it has a photosensitive layer and a protective layer thereon. An intermediate layer may be provided for the purpose of bonding the two.

  The lithographic printing plate precursor of the present invention improves the detachability between plates when stacking a large number of sheets without interleaving paper, and also improves the detachability between the interleaving paper and the plate even when the interleaving papers are stacked. For this purpose, the surface of the protective layer of the lithographic printing plate precursor may be matted. As a method of matting the surface of the protective layer, a method of adding a matting agent or the like in the protective layer, a method of spray-coating a solution in which a water-soluble resin or a water-soluble resin and a matting agent are dissolved and dispersed on the surface of the protective layer and so on. Examples of the matting agent include silicon dioxide, zinc oxide, titanium oxide, alumina powder, starch, starch, polymer particles (for example, particles such as polyacrylic acid and polystyrene), and the like.

  Furthermore, other functions can be imparted to the protective layer. For example, the addition of a colorant (such as a water-soluble dye) that excels in the transmission of light of the wavelength used for exposure and can efficiently absorb light of a wavelength that does not contribute to image formation is safe without causing a decrease in sensitivity. Light suitability can be further enhanced.

[Developer]
In the development processing of the lithographic printing plate precursor according to the invention, the pH is 8 to 11, preferably pH 9.0, containing (1) a sodium salt, (2) a surfactant, and (3) a water-soluble cationized starch. A weak alkaline developer which is an aqueous solution of ˜11.0 can be used.

(1) Sodium salt The sodium salt exhibits alkalinity when dissolved in water, and examples thereof include sodium silicate and sodium orthosilicate. A commercially available sodium salt can be used as it is. For example, it is sold under trade names such as sodium silicate No. 1, sodium silicate No. 2, sodium silicate No. 3, sodium silicate No. 4, and sodium orthosilicate.
The content of the sodium salt is preferably 0.01 to 20% by mass, more preferably 0.1 to 20% by mass in the developer. When the content is less than 0.01% by mass, the non-image area may be stained, and when it exceeds 20% by mass, the developability may be deteriorated. The developer can be easily adjusted to a specific pH of 8.0 to 11 by containing a sodium salt. That is, the pH can be adjusted to 8.0 to 11 by adjusting the content of the sodium salt.

(2) Water-soluble cationized starch The water-soluble cationized starch used in the developer includes, for example, a halohydrin group having a plurality of cationic atoms in one molecule and having reactivity with a hydroxyl group in the molecule. Alternatively, it can be obtained by reacting a hydroxyl group of starch with a polymer-type cationizing agent having an epoxy ring to generate an ether bond.

An example of the polymer cationizing agent is a cationic polymer obtained by copolymerizing one or more monomers having a halohydrin group or an epoxy ring and one or more cationic monomers.
Specific examples of the monomer having a halohydrin group or an epoxy ring include 3-chloro-2-hydroxypropyl diallylamine hydrochloride, 3-chloro-2-hydroxypropyl diallylmethylammonium chloride, and 3-chloro-2-hydroxypropyl diallyl. Ethylammonium chloride, 3-bromo-2-hydroxypropyl diallylamine hydrochloride, 3-bromo-2-hydroxypropyl diallylmethylammonium chloride, 3-bromo-2-hydroxypropyl diallylethylammonium chloride, 3-iodo-2-hydroxypropyl Diallylamine hydrochloride, 3-iodo-2-hydroxypropyldiallylmethylammonium chloride, 3-iodo-2-hydroxypropyldiallylethylammonium chloride, Glycidyl diallylamine hydrochloride, glycidyl diallyl ammonium chloride, include glycidyl diallyl ethyl chloride, examples shown herein may be used without any particular problem as far as it is a monomer containing a halohydrin group or an epoxy ring, for example.

  Specific examples of the cationic monomer include diallyldimethylammonium chloride, diallyldiethylammonium chloride, diethylaminoethyl methacrylate, methacryloyloxyethyltrimethylammonium methylsulfate, methacryloyloxyethyltrimethylammonium chloride, diallylpyridinium chloride, diallylpiperidinium chloride, etc. There are compounds such as Of course, the cationic monomer is not limited to those listed in these examples.

  Weight average by gel filtration chromatography (GFC) measurement of a cationic polymer (polymeric cationizing agent) obtained by copolymerizing one or more monomers having a halohydrin group or epoxy ring and one or more cationic monomers The molecular weight (Mw) is preferably 1,000 to 1,000,000, more preferably 5,000 to 500,000. The molar ratio of the monomer having a halohydrin group or epoxy ring and the cationic monomer is preferably 1: 1 to 1:50, more preferably 1:10 to 1:25. The degree of cationization of the cationic polymer is preferably 0.01 to 2.00% by mass, more preferably 0.015 to 1.00% by mass. The degree of cationization is calculated according to Kjeldahl analysis by calculating the nitrogen content from the content of nitrogen atoms in one molecule of cationized starch. And determined as the degree of cationization (degree of substitution). The weight average molecular weight can be measured by the GFC method.

  The starch that can be used in the present invention is a starch that is generally used, and is not particularly limited. Examples of the starch are starches such as corn, potato, tapioca, rice and wheat. This is just an example.

  Commercially available cationized starch can be used as the water-soluble cationized starch. For example, Starlight PMC Paper Strength Enhancer Series DD-4280, Oji Cornstarch Cationized Starch, Nissho Chemical EX-3, Excel DH, Betrosize J, Betrosize U Cationic Starch, Sansho Mermaid C -50, C-50H, Mermaid M-350B, SB GUM-POSIT, and the like.

  The content of the water-soluble cationized starch is preferably 0.1 to 10% by mass, more preferably 1.0 to 10% by mass in the developer. Here, if the content is less than 0.1% by mass, it may be stained, and if it exceeds 10% by mass, it may be precipitated in the developer.

(3) Surfactant Surfactants include anionic, nonionic, and cationic surfactants.
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, sodium N-methyl-N-oleyl taurine, N-alkylsulfosuccinic acid monoamido 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 Examples thereof include partially saponified products of maleic acid copolymers, partially saponified products of olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates. Of these, dialkylsulfosuccinic acids, alkylsulfuric acid ester salts and alkylnaphthalenesulfonic acid salts are preferably used.

  The cationic surfactant is not particularly limited, and conventionally known cationic surfactants can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

  Nonionic surfactants include polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid. Amidoethylene oxide adducts, fat and oil ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, dimethylsiloxane-ethylene oxide block copolymers, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymers, and polyhydric alcohol type glycerol Fatty acid ester, fatty acid ester of pentaerythritol, sorbitol and / or sorbitan fatty acid ester Ethylene oxide adducts, fatty acid esters of sucrose, fatty acid esters of polyhydric alcohols, such as fatty acid amides of alkanolamines.

  Surfactants include ethylene oxide adducts of sorbitol and / or sorbitan fatty acid esters, polypropylene glycol ethylene oxide adducts, dimethylsiloxane-ethylene oxide block copolymers, dimethylsiloxane-ethylene oxide block copolymers, dimethylsiloxane- (propylene oxide-ethylene). Oxide) block copolymers and fatty acid esters of polyhydric alcohols are more preferred.

  Further, from the viewpoint of stable solubility or turbidity in water, the nonionic surfactant preferably has an HLB value of 6 or more, more preferably 8 or more. Also, acetylene glycol-based and acetylene alcohol-based oxyethylene adducts, fluorine-based and silicon-based surfactants can be used in the same manner.

These surfactants can be used alone or in combination. Moreover, 0.01-10 mass% is preferable in conversion of an active ingredient, and, as for content in the developing solution of these surfactant, 0.01-5 mass% is more preferable.
By using the developer, the lithographic printing plate precursor according to the invention can be developed by one-liquid processing. In the one-liquid process, the development process, the water washing process, and the gumming process, which are preferably the minimum required in a standard process, can be simultaneously performed with one liquid.

  The present invention will be described more specifically with reference to the following examples. However, the present examples do not limit the present invention.

[Production of support]
Aluminum having a thickness of 0.30 mm (material 1050) was degreased with alkali, then the surface was polished with a nylon brush while applying a water suspension of palmiston, and washed thoroughly with water. Then, 70 ° C., 15 mass% sodium hydroxide aqueous solution was poured for 5 seconds, the surface was etched by 3 g / m ² , further washed with water, and then electrolytically roughened at 200 coulomb / dm ² in a 1N hydrochloric acid bath. Processed. Subsequently, the surface was etched again with a 15% by mass aqueous sodium hydroxide solution, washed with water, and then immersed in a 20% by mass nitric acid aqueous solution for desmutting. Next, anodization was performed in a 15% by mass sulfuric acid aqueous solution to form a 2.0 g / m ² oxide film. After washing with water, 1% by mass potassium fluoride at 50 ° C. and 10% by mass phosphoric acid. It was post-treated with a mixed solution of monosodium, washed with water and dried.

[Synthesis Example 1: Specific alkali-soluble resin (A-1)]
In a 500 ml four-necked flask, nitrogen gas, a reflux tube, a thermometer, and a stirrer were prepared. 23 g of acrylic acid, 12.5 g of acryloylmorpholine, 2.0 g of dicyclopentanyl methacrylate (FA-513M, Hitachi Chemical Co., Ltd.) 12.5 g of ethyl carbitol acrylate (ECA) was dissolved in 100 g of propylene glycol monomethyl ether (PGME). Under nitrogen atmosphere, the mixture is heated and stirred at 85 ° C., and 0.4 g of a polymerization initiator (2,2′-azobis (2-methylbutyronitrile), V-59, manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved in 4 g of PGME and added. Thereafter, 23 g of acrylic acid, 12.5 g of acryloylmorpholine, 2.0 g of FA-513M and 12.5 g of ECA dissolved in 100 g of PGME were added dropwise and stirred for 4 hours. Further, 0.2 g of V-59 was dissolved in 4 g of PGME and stirred for 2 hours. Thereafter, 48 g of GMA was added to the reaction solution at 85 ° C., and an addition reaction was performed for 6 hours. After the reaction, 500 ppm of a polymerization inhibitor (N-nitrosophenylhydroxylamine / aluminum salt, Q-1301, manufactured by Wako Pure Chemical Industries, Ltd.) was added to the reaction solution. A target resin having an Mw of 17,000 was obtained from GPC measurement.

[Synthesis Example 2: Specific alkali-soluble resin (A-2)]
In a 500 ml four-necked flask, nitrogen gas, a reflux tube, a thermometer, and a stirrer were prepared. 27.5 g of acrylic acid, 7.5 g of acryloylmorpholine, 5.0 g of FA-513M, 10 g of ethyl carbitol acrylate ( ECA) was dissolved in 100 g of propylene glycol monomethyl ether (PGME). In a nitrogen atmosphere, the mixture is heated and stirred at 85 ° C., 0.4 g of a polymerization initiator (V-59, manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved in 4 g of PGME and added, and then 27.5 g of acrylic acid and 7.5 g of acryloyl. A solution prepared by dissolving morpholine, 5.0 g FA-513M, 10 g ECA in 100 g PGME was added dropwise for 4 hours. Further, 0.2 g of V-59 was dissolved in 4 g of PGME and stirred for 2 hours. Thereafter, 50 g of GMA was added to the reaction solution at 85 ° C., followed by addition reaction for 6 hours. After the reaction, 500 ppm of Q-1301 was added to the reaction solution. A target resin having an Mw of 11,000 was obtained from GPC measurement.

[Synthesis Example 3: Specific alkali-soluble resin (A-3)]
In a 500 ml four-necked flask, nitrogen gas, a reflux tube, a thermometer, and a stirrer were prepared. 26 g of acrylic acid, 9.5 g of acryloylmorpholine, 2.5 g of FA-513M, 9.5 g of ethyl carbitol acrylate ( ECA), 2.5 g of 3- (2H-1,2,3-benzotriazol-2-yl) -4-hydroxyphenethyl methacrylate was dissolved in 100 g of propylene glycol monomethyl ether (PGME). In a nitrogen atmosphere, the mixture was heated and stirred at 85 ° C., 0.4 g of a polymerization initiator (V-59, manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 4 g of PGME, and then 26 g of acrylic acid, 9.5 g of acryloylmorpholine, 2.5 g FA-513M, 9.5 g ECA, 2.5 g 3- (2H-1,2,3-benzotriazol-2-yl) -4-hydroxyphenethyl methacrylate dissolved in 100 g PGME The mixture was stirred for 4 hours while dropping. Further, 0.2 g of V-59 was dissolved in 4 g of PGME and stirred for 2 hours. Thereafter, 48 g of GMA was added to the reaction solution at 85 ° C., and an addition reaction was performed for 6 hours. After the reaction, 500 ppm of Q-1301 was added to the reaction solution. The target resin having Mw of 15000 was obtained from GPC measurement.

[Example 1]
Photosensitive solution (a) having the following composition was prepared. Photosensitive solution A was applied onto the above aluminum plate so that the coating weight after drying was 1.9 g / m ² and dried at 90 ° C. for 5 minutes to obtain a lithographic printing plate precursor.
(Photosensitive solution a)
・ Specific alkali-soluble resin (A-1) 0.8g
・ Binder resin (M-1) 0.8g
・ Specific silane coupling agent (S-1) 1.0 g
・ Polymerizable compound (E-1) 1.6 g
・ Infrared absorber (IRA-I) 0.05g
-Radical polymerizable initiator 1: 0.1 g of organic boron salt (B-1)
Radical polymerizable initiator 2: Onium salt (I-1) 0.1 g
・ Dye: Oil Blue 613 (manufactured by Orient Chemical Co., Ltd.) 0.05g
・ Solvent: 20 ml of propylene glycol monomethyl ether
・ Solvent: Tetrahydrofuran 20ml

(Water-soluble protective layer)
The following water-soluble protective layer coating solution was applied to the surface of the photosensitive layer with a wire bar and dried at 90 ° C. for 3 minutes with a drying apparatus. The coating amount was 1.0 g / m ² .

(Water-soluble protective layer coating solution)
・ Polyvinyl alcohol 100g
(Nippon Synthetic Chemical Industries, Ltd., saponification degree 92 mol%, polymerization degree 500)
・ Surfactant (Japanese emulsifier, EMALEX 710) 0.1g
・ 400g distilled water

[Example 2]
A lithographic printing plate precursor was obtained in the same manner as in Example 1 using a photosensitive solution B having the following composition instead of the photosensitive solution A.
(Photosensitive solution b)
・ Specific alkali-soluble resin (A-2) 0.8g
・ Binder resin (M-1) 0.8g
・ Specific silane coupling agent (S-1) 1.0 g
・ Polymerizable compound (E-1) 1.6 g
・ Infrared absorber (IRA-I) 0.05g
-Radical polymerizable initiator 1: 0.1 g of organic boron salt (B-1)
Radical polymerizable initiator 2: Onium salt (I-1) 0.1 g
・ Dye: Oil Blue 613 (manufactured by Orient Chemical Co., Ltd.) 0.05g
・ Solvent: 20 ml of propylene glycol monomethyl ether
・ Solvent: Tetrahydrofuran 20ml

[Example 3]
A lithographic printing plate precursor was obtained in the same manner as in Example 1 by using a photosensitive solution C having the following composition instead of the photosensitive solution A.
(Photosensitive solution C)
・ Specific alkali-soluble resin (A-3) 0.8g
・ Binder resin (M-1) 0.8g
・ Specific silane coupling agent (S-1) 1.0 g
・ Polymerizable compound (E-1) 1.6 g
・ Infrared absorber (IRA-I) 0.05g
-Radical polymerizable initiator 1: 0.1 g of organic boron salt (B-1)
Radical polymerizable initiator 2: Onium salt (I-1) 0.1 g
・ Dye: Oil Blue 613 (manufactured by Orient Chemical Co., Ltd.) 0.05 g
・ Solvent: 20 ml of propylene glycol monomethyl ether
・ Solvent: Tetrahydrofuran 20ml

[Comparative Example 1]
A lithographic printing plate precursor was obtained in the same manner as in Example 1 by using a photosensitive solution having the following composition instead of the photosensitive solution (a).
(Photosensitive solution)
・ Comparison alkali-soluble resin 1 (C-1) 0.8 g
・ Binder resin (M-1) 0.8g
・ Specific silane coupling agent (S-1) 1.0 g
・ Polymerizable compound (E-1) 1.6 g
・ Infrared absorber (IRA-I) 0.05g
-Radical polymerizable initiator 1: 0.1 g of organic boron salt (B-1)
Radical polymerizable initiator 2: Onium salt (I-1) 0.1 g
・ Dye: Oil Blue 613 (manufactured by Orient Chemical Co., Ltd.) 0.05g
・ Solvent: 20 ml of propylene glycol monomethyl ether
・ Solvent: Tetrahydrofuran 20ml

[Comparative Example 2]
A lithographic printing plate precursor was obtained in the same manner as in Example 1 using a photosensitive solution having the following composition instead of the photosensitive solution (a).
(Photosensitive solution)
・ Comparison alkali-soluble resin 2 (C-2) 0.8 g
・ Binder resin (M-1) 0.8g
・ Specific silane coupling agent (S-1) 1.0 g
・ Polymerizable compound (E-1) 1.6 g
・ Infrared absorber (IRA-I) 0.05g
-Radical polymerizable initiator 1: 0.1 g of organic boron salt (B-1)
Radical polymerizable initiator 2: Onium salt (I-1) 0.1 g
・ Dye: Oil Blue 613 (manufactured by Orient Chemical Co., Ltd.) 0.05g
・ Solvent: 20 ml of propylene glycol monomethyl ether
・ Solvent: Tetrahydrofuran 20ml

上記式において、括弧に付加された添え字は重量分率を表す。

In the above formula, the subscript added to the parenthesis represents the weight fraction.

[Evaluation method]
The lithographic printing plate precursors obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were evaluated as follows.
1. Evaluation of development processability The planographic printing plate precursor was exposed to a 50% dot image and a solid image of AM200 line at a resolution of 2400 dpi, an external drum rotation speed of 360 rpm and an irradiation energy of 100 mJ / cm ² using a Kodak Trend setter 800 QTM. . This was immersed in a developer having the following composition for 20 seconds and developed. When completely developed, it was evaluated as “◯”, and when it was poorly developed, it was evaluated as “x” (Table 1).
(Developer)
・ Water-soluble cationized starch (made by Seiko PMC, DD-4280) 185 g
・ Surfactant (Japanese emulsifier, EMALEX 710) 0.1g
・ Silica silicate 3 5g
・ Sodium tripolyphosphate 1g
・ EDTA 1g
・ Distilled water 310g

2. Image Strength Evaluation A 50% halftone dot image obtained in the same manner as in “1. Development processing evaluation” was immersed in 10% dampening water (News King Alky, manufactured by Toyo Ink Co., Ltd.) for 2 minutes, and then absorbent cotton Then, it was rubbed strongly for 3 minutes to evaluate whether the image was rubbed or peeled off. When there is no change in the image portion, it is indicated as “◯”, when it is slightly peeled but within the practical range, it is indicated as “Δ”, and when it is completely peeled off, it is indicated as “X”.

3. Ink smear test After lightly wiping the 50% halftone dot image obtained in the same manner as in “1. Development processability evaluation” with a hand roller, newspaper ink (Toyo Ink Co., Ltd., Vantean Echo Sumi) was used. The evaluation plate was used to make it thick, and it was lightly wiped with water again to check for ink stains. When the non-image area is not stained, “◯” is indicated, and when the non-image area is stained, “X” is indicated.

4). Chemical resistance test A 50% halftone image obtained in the same manner as in “1. Development processing evaluation” was dropped on Ultraplate Cleaner Mild (manufactured by SK Liquid Manufacturing Co., Ltd.) for 15 minutes, wiped with absorbent cotton, and then dropped. The part is completely fixed with cello tape (registered trademark) (manufactured by Nichiban Co., Ltd.). Then peel off vigorously. Evaluation was based on how the image area was affected. When there is no change in the image area, it is indicated as “◯”, when there is no peeling but slightly dissolved, it is indicated as “Δ”, and when it is completely peeled off, it is indicated as “X”.

  From Table 1, it was shown that the lithographic printing plate precursors of Examples 1 to 3 can provide printing plates having excellent developability, printing durability, and chemical resistance by the one-liquid development treatment.

Claims (6)

The following formulas (I) to (III)

(In formula, R < ¹ >, R < ² >, R < ³ > shows the C1-C10 alkyl group which may have a hydrogen atom or a substituent independently, and L shows the integer of 1-10.)
The content of the repeating unit represented by formula (I) is 3% by mass to 20% by mass, and the content of the repeating unit represented by formula (II) is 15% by mass. An alkali-soluble resin having a content of the repeating unit represented by the formula (III) of 15 to 35% by mass;
Formula (IV) below

(In the formula, R ^{4 to} R ⁶ independently represent a hydrogen atom, or an alkyl group or an alkoxy group which may have a substituent, X represents an ester bond, an amide bond or a phenyl group, and Z represents , 0 or 1, and Y represents an integer of 0 to 10.)
A silane coupling agent represented by:
An infrared absorber;
A radical polymerizable initiator;
A photosensitive composition containing at least a polymerizable compound having an ethylenic double bond.   The photosensitive composition according to claim 1, wherein the alkali-soluble resin further contains 1 to 67% by mass of a repeating unit derived from an α, β-unsaturated carboxylic acid.   The photosensitive composition according to claim 1, wherein a content of the silane coupling agent is 15% by mass to 40% by mass.   A negative lithographic printing plate precursor comprising a support and a photosensitive layer formed on the support using the photosensitive composition according to claim 1.   The negative lithographic printing plate precursor according to claim 4, further comprising a protective layer formed on the photosensitive layer. A step of image-exposing the negative lithographic printing plate precursor according to claim 4 or 5 with an infrared laser;
Image formation including at least a step of developing the image-exposed photosensitive layer using a weak alkaline developer having a pH of 8 to 11 containing at least a sodium salt, a surfactant, and a water-soluble cationized starch. Method.