JP5388908B2 - Positive lithographic printing plate precursor for infrared laser and plate making method of lithographic printing plate - Google Patents

Description

  The present invention relates to a positive planographic printing plate precursor for an infrared laser and a method for making a planographic printing plate.

Conventionally, various photosensitive compositions have been used as visible image forming and lithographic printing plate materials. In particular, the development of lasers in lithographic printing in recent years has been remarkable, and in particular, solid lasers and semiconductor lasers having a light emitting region from the near infrared to the infrared are easily available in high output and small size. These lasers are very useful as an exposure light source when directly making a plate from digital data such as a computer.
The positive lithographic printing plate precursor for infrared laser contains an alkali-soluble binder resin and an infrared absorbent that absorbs light and generates heat as essential components. This infrared absorber or the like acts as a development inhibitor that substantially lowers the solubility of the binder resin in the developer by interaction with the binder resin in the unexposed area (image area), and the exposed area (non-image area). Then, the interaction between the infrared absorbent and the binder resin is weakened by the generated heat and is dissolved in an alkali developer to form a lithographic printing plate. However, in such a positive lithographic printing plate material for infrared laser, the processability (development latitude) with a fatigue developer having a decreased activity is not sufficient.
In order to solve such a problem of development latitude, it is conceivable to use a recording layer made of a material that can develop a non-image area more easily, that is, has a property of better solubility in an alkaline aqueous solution. However, such a recording layer is chemically weak even in the image area, and is easily damaged by a developer, an ink washing solvent used during printing, a plate cleaner, and the like. There was a problem of poor chemical resistance.
In order to solve this problem, a method of stacking recording layers is known (Patent Document 1).

JP 11-218914 A

However, the difference between the solubility resistance of the unexposed area (image area) with respect to the developer and the solubility of the exposed area (non-image area) only under the method of layering the recording layer ( Discrimination; hereinafter also referred to as “dissolving discriminating” or “dissolving discriminability”) is not yet sufficient, and there is a problem that overdevelopment and development defects are likely to occur due to fluctuations in use conditions. A material excellent in durability in the latitude and unexposed areas has been eagerly desired.
An object of the present invention is to develop a positive lithographic printing plate precursor for infrared laser with excellent development latitude, dissolution discrimination and printing durability, and less deterioration in developability with time after exposure, and positive lithographic printing for infrared laser. It is to provide a plate making method of a lithographic printing plate using a plate precursor.

The above-described problems of the present invention have been solved by the following means <1> and <9>. They are listed together with <2> to <8> and <10>, which are preferred embodiments.
<1> A lower layer containing a water-insoluble and alkali-soluble resin and an infrared absorber and an upper layer containing a graft copolymer having a sulfonamide group, an active imide group and / or an amide group are sequentially laminated on the support. A positive lithographic printing plate precursor for infrared laser, wherein the graft copolymer is a polyurethane resin having a structural unit derived from an ethylenically unsaturated monomer as a graft chain,
<2> The positive lithographic printing plate precursor for infrared laser according to <1>, wherein the polyurethane resin is a reaction product of diisocyanate and diol,
<3> The infrared laser according to <2>, wherein the diol includes a diol (A-1) having a graft chain containing a group selected from the group consisting of a sulfonamide group, an active imide group, and an amide group. Positive type lithographic printing plate precursor,
<4> The positive lithographic printing plate precursor for infrared laser according to <3>, wherein the diol (A-1) has a sulfonamide group,
<5> The diol (A-1) is a radical of an ethylenically unsaturated monomer having a sulfonamide group, an active imide group and / or an amide group in the presence of a compound having a mercapto group and two hydroxyl groups. A positive lithographic printing plate precursor for infrared laser according to the above <3> or <4>, which is a diol compound obtained by polymerization,
<6> The positive lithographic printing plate precursor for infrared laser according to any one of the above <3> to <5>, wherein the diol further includes a diol (A-2) having a carboxyl group.
<7> The positive lithographic printing plate precursor for infrared laser according to any one of the above <1> to <6>, wherein a terminal of the graft chain is bonded to a diol compound residue via a sulfur atom,
<8> The positive lithographic printing plate precursor for infrared laser according to any one of the above <1> to <7>, wherein the upper layer further contains an infrared absorber,
<9> Using an exposure step of exposing the positive lithographic printing plate precursor for infrared laser according to any one of <1> to <8> above, and an alkaline aqueous solution having a pH of 8.5 to 10.8. A process for making a lithographic printing plate comprising, in this order, development steps for developing,
<10> The plate making method of a lithographic printing plate as described in <9>, wherein the aqueous alkali solution contains an anionic surfactant or a nonionic surfactant.

  According to the present invention, the positive lithographic printing plate precursor for infrared laser having excellent development latitude, dissolution discrimination and printing durability, and less deterioration in developability with time after exposure, and the positive lithographic printing for infrared laser, A plate making method of a lithographic printing plate using a plate original plate could be provided.

It is explanatory drawing which shows schematic structure of an automatic developing processor.

(Infrared laser lithographic printing plate precursor)
The positive lithographic printing plate precursor for infrared laser of the present invention (hereinafter also simply referred to as “lithographic printing plate precursor”) comprises a lower layer containing a water-insoluble and alkali-soluble resin and an infrared absorber on a support, a sulfonamide An upper layer containing a graft copolymer having a group, an active imide group and / or an amide group, and the graft copolymer has a structural unit derived from an ethylenically unsaturated monomer as a graft chain. It is characterized by being a polyurethane resin.
The lithographic printing plate precursor of the present invention is a lithographic printing plate precursor that is widely sensitized to infrared rays, is particularly suitable for infrared laser exposure, and gives a positive image.
In the lithographic printing plate precursor according to the invention, two layers of a lower layer and an upper layer are laminated as essential layers on a support. In addition to these two upper and lower layers, a hydrophilic undercoat layer or the like may be appropriately provided between the support and the lower layer.
The lower layer includes a water-insoluble and alkali-soluble resin. In the present invention, “water-insoluble” means insoluble in neutral ion-exchanged water, and “alkali-soluble” means standard development time in an alkaline aqueous solution at pH 8.5 to 13.5. It is soluble in the treatment of.
The upper layer and the lower layer form a recording layer (also referred to as “photosensitive layer”) by these two layers. The upper layer is also referred to as a recording layer upper layer, and the lower layer is also referred to as a recording layer lower layer.

In general, a polymer having high durability tends to have low developer permeability, is easily influenced by developer activity (development latitude is insufficient), and both are in a trade-off relationship. In contrast, the polyurethane resin has a graft structure, and the sulfonamide group, the active imide group and / or the amide group in the graft part have high mobility while maintaining the high durability of the main chain polyurethane. So that the developer can easily penetrate.
Moreover, the lithographic printing plate precursor according to the present invention is excellent in solvent discriminability (dissolution discrimination) by including the polyurethane resin in the upper layer.
Furthermore, when the polyurethane resin coexists with the infrared absorber, the interaction between the sulfonamide group and the infrared absorber is large, and “ON” in the unexposed area (at the time of application), “OFF” in the exposed area. ”Is considered to have improved the melting discretion in order to become more effective.
Hereinafter, the details of the positive planographic printing plate precursor of the present invention will be described.

<Polyurethane resin>
The positive type lithographic printing plate precursor for infrared laser of the present invention comprises a graft copolymer having a sulfonamide group, an active imide group and / or an amide group in the upper layer, and the graft copolymer comprises an ethylenically unsaturated monomer. It is a polyurethane resin having a structural unit derived from the body as a graft chain. That is, the polyurethane resin contained in the upper layer of the positive lithographic printing plate precursor for infrared laser of the present invention has a polyurethane chain as a main chain and a structural unit derived from an ethylenically unsaturated monomer as a graft chain. And a polyurethane resin having a sulfonamide group, an active imide group and / or an amide group.
The polyurethane resin may have a sulfonamide group, an active imide group and / or an amide group in the graft chain or in the polyurethane main chain, but preferably in the graft chain. .
The active imide group is preferably an imide group having one or more sulfonyl groups bonded thereto, more preferably a carbonylsulfonimide group or a disulfonimide group, and still more preferably a carbonylsulfonimide group. .
The sulfonamide group, active imide group and amide group preferably have at least one hydrogen atom on the nitrogen atom, and all the groups on the nitrogen atom other than the carbonyl group and the sulfonyl group are all hydrogen atoms. More preferably.

The polyurethane resin preferably has a thermally crosslinkable group.
In the polyurethane resin, the thermally crosslinkable group may be contained in the graft chain or in the polyurethane main chain, but is preferably contained in the graft chain.
Examples of the thermally crosslinkable group include N-hydroxymethyl group, N-alkoxymethyl group, urea group, urethane group, N-acyloxyphthalimide group, epoxy group, oxetanyl group, and oxazolyl group.

In the present invention, a “macromonomer” refers to a polymer having two alcoholic hydroxyl groups at one end that allow it to behave as a monomer.
The polyurethane resin used in the present invention contains a specific ethylenically unsaturated monomer (such as an ethylenically unsaturated monomer having a sulfonamide group) as a mercaptan having two or more hydroxyl groups and one mercapto group. A polyurethane resin obtained by reacting a polymer (a kind of macromonomer) obtained by radical polymerization in the presence of a chain transfer agent with a polyisocyanate as a polyol component is preferable. Examples of the method for producing such a polyurethane resin include the methods described in JP-A-4-178416, JP-A-4-178417, and the like.
The specific ethylenically unsaturated monomer is a compound having a sulfonamide group, an active imide group and / or an amide group and a radically polymerizable unsaturated group. Examples of such monomers include monomers containing amide groups and radical polymerizable unsaturated groups such as acrylamide and methacrylamide, N- (4-sulfamoylphenyl) methacrylamide, N-phenylsulfonyl. Monomers having a sulfonamide group and a radically polymerizable unsaturated group such as methacrylamide and N-phenylsulfonylmaleimide, and monomers having an active methylene group and a radically polymerizable unsaturated group described in JP-A-63-127237 Examples include a polymer.
The polyurethane resin most preferably has a sulfonamide group from the viewpoints of printing durability and production suitability.
These monomers having an ethylenically unsaturated group can be used singly or as a mixture of two or more.

Furthermore, the macromonomer may contain an ethylenically unsaturated monomer other than the specific ethylenically unsaturated monomer as a constituent component.
In particular, a monomer having a thermally crosslinkable group and an ethylenically unsaturated group is preferable as the copolymerization monomer. Specific examples of the compound having a thermally crosslinkable group and an ethylenically unsaturated group include (meth) acrylamides such as N- (hydroxymethyl) acrylamide and N- (butoxymethyl) acrylamide as represented by formula (1). , A monomer having an ethylenically unsaturated group represented by formula (2), a monomer having an ethylenically unsaturated group represented by formula (3), a urea group represented by formula (4), or A monomer having a urethane group and an ethylenically unsaturated group, a monomer having an epoxy group and an ethylenically unsaturated group such as glycidyl methacrylate represented by the formula (5), and represented by the formula (6) A monomer having an oxetanyl group and an ethylenically unsaturated group such as (3-methyl-3-oxetanyl) methyl methacrylate, and a monomer having an oxazoline group and an ethylenically unsaturated group represented by the formula (7) amount And the like.

In formulas (1) to (7), R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and R ₃ to R ₇ are each independently Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and two or more groups may be bonded to form a ring structure, and R ₈ and R ₉ are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms. Represents a group, a cycloalkyl group, an alkenyl group, an alkynyl group or an aryl group, A and B represent —O—, —S— or —N (R ₁₀ ) —, and R ₁₀ represents a hydrogen atom or a carbon number. 1 to 10 alkyl groups are represented, and X represents a single bond or a divalent linking group. X is preferably a single bond or an alkylene group having 1 to 10 carbon atoms.

  Furthermore, examples of the monomer copolymerized with the macromonomer include aryl acrylates such as methyl acrylate, methacrylic acid esters such as methyl methacrylate, aryl methacrylates, acrylamide, N-alkyl acrylamides, and allyl compounds. , Vinyl ethers, vinyl esters, styrenes such as methylstyrene, crotonic acid esters, dialkyl itaconates, maleic acids such as dimethyl malate and dibutyl fumarate or dialkyls of fumaric acid, maleimides, N-vinyl pyrrolidone , N-vinylpyridine, acrylonitrile, methacrylonitrile and the like.

  Examples of the solvent used in producing the macromonomer include ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl glycol, 2-methoxyethyl acetate, 1-methoxy. 2-propanol, 1-ethoxy-2-propanol, 1-methoxy-2-propyl acetate, 1-ethoxy-2-propyl acetate, 2-butanone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl Examples thereof include sulfoxide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, toluene, ethyl acetate, methyl lactate, and ethyl lactate. These solvents are used alone or in combination of two or more.

Examples of mercaptan chain transfer agents having two or more hydroxyl groups and one mercapto group used in the production of the macromonomer include 1-mercapto-1,1-methanediol, 1-mercapto-1,1- Ethanediol, 3-mercapto-1,2-propanediol, 2-mercapto-1,1-methanediol, 2-mercapto-2-methyl-1,3-propanediol, 2-mercapto-2-ethyl-1, Examples include 3-propanediol, 1-mercapto-2,2-propanediol, 2-mercaptoethyl-2-methyl-1,3-propanediol, 2-mercaptoethyl-2-ethyl-1,3-propanediol, and the like. It is done.
As preferred specific examples of the macromonomer, MM-10-16, MM-21-26, and MM-30-38 are shown below, but it goes without saying that the macromonomer that can be used in the present invention is not limited to these. Yes.

  The chemical structures of C-1, A-1 to A-3, B-1 to B-9, and O-1 to O-4 are shown below.

Among these, as the macromonomer, a macromonomer having a sulfonamide group of MM-10 to MM-13, and a macro having a sulfonamide group and a thermally crosslinkable group of MM-31, MM-34, and MM-35. Monomers are particularly preferred.
The weight average molecular weight (Mw) of the macromonomer thus obtained is not particularly limited, but is preferably 500 or more and 20,000 or less.
The macromonomer is preferably reacted with diisocyanate and another diol component as a part of the diol component to obtain the polyurethane resin.

The polyisocyanate compound that can be used for the synthesis of the polyurethane resin and the polyol compound other than the macromonomer are not particularly limited, and known ones can be used.
The polyisocyanate compound is preferably a diisocyanate compound, and more preferably a compound represented by the following formula (I).
The polyol compound other than the macromonomer is preferably a diol compound. In addition, the polyol compound preferably includes a polyol compound having a carboxy group, more preferably includes a diol compound having a carboxy group, and includes a compound represented by the following formula (II) or formula (III). Is more preferable.

In formula (I), R ¹ represents a divalent linking group. Examples of the divalent linking group include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group, an alkylene group having 2 to 10 carbon atoms, and an arylene group having 6 to 30 carbon atoms. Is preferred. R ¹ may have another functional group that does not react with the isocyanate group.
In the formula (II), R ² represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, an alkoxy group, or an aryloxy group. Here, R ² may have a substituent.
R ² is preferably a hydrogen atom, an unsubstituted alkyl group having 1 to 8 carbon atoms, or an unsubstituted aryl group having 6 to 15 carbon atoms.
In formula (II) or formula (III), R ³ , R ⁴ and R ⁵ may be the same or different and each represents a single bond or a divalent linking group. Examples of the divalent linking group include an aliphatic hydrocarbon group and an aromatic hydrocarbon group. Here, R ³ , R ⁴ and R ⁵ may have a substituent. Preferred examples of R ³ , R ⁴ and R ⁵ include an unsubstituted alkylene group having 1 to 20 carbon atoms or an unsubstituted arylene group having 6 to 15 carbon atoms, and an unsubstituted alkylene group having 1 to 8 carbon atoms. More preferred is an alkylene group. R ³ , R ⁴ and R ⁵ may have other functional groups that do not react with isocyanate groups.
In formula (III), Ar represents a trivalent aromatic hydrocarbon which may have a substituent, and is preferably a trivalent aromatic hydrocarbon group having 6 to 15 carbon atoms.

Specific examples of the diisocyanate compound represented by the formula (I) include those shown below, but the present invention is not limited thereto.
2,4-tolylene diisocyanate, dimer of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylylene diisocyanate, metaxylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5 -Aromatic diisocyanate compounds such as naphthylene diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate; aliphatic diisocyanate compounds such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, dimer acid diisocyanate; Isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate), methylcyclohexane-2,4 (or 2,6) -diisocyanate, 1,3- (isocyanate) And alicyclic diisocyanate compounds such as anate methyl) cyclohexane; and diisocyanate compounds which are a reaction product of a diol and diisocyanate such as an adduct of 1 mol of 1,3-butylene glycol and 2 mol of tolylene diisocyanate. Among these, those having an aromatic ring such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, and tolylene diisocyanate are preferable from the viewpoint of printing durability.

Specific examples of the diol compound having a carboxyl group represented by the formula (II) or formula (III) include those shown below, but the present invention is not limited thereto.
3,5-dihydroxybenzoic acid, 2,2-bis (hydroxymethyl) propionic acid, 2,2-bis (hydroxyethyl) propionic acid, 2,2-bis (3-hydroxypropylpropionic acid, 2,2-bis (Hydroxymethyl) acetic acid, bis (4-hydroxyphenyl) acetic acid, 4,4-bis (4-hydroxyphenyl) pentanoic acid, tartaric acid, etc. Among them, 2,2-bis (hydroxymethyl) propionic acid, 2 , 2-bis (hydroxyethyl) propionic acid is more preferred from the viewpoint of reactivity with isocyanate.

  Preferable specific examples of the polyurethane resin that can be used in the present invention include PU-10 to 16, PU-21 to 26, PU-30 to 38, PU-43 to 67, PU-71 to 73, and PU- Of course, 81 to 87 are shown, but the polyurethane resin is not limited thereto. In addition, the number described under each following monomer name represents the molar ratio of each used monomer.

MM-10-16, MM-21-26, and MM-30-38 represent the above-mentioned macromonomer, respectively.
Moreover, chemical structure of said DI-1-8 and DO-1-10 is shown below.

Among these, as said polyurethane resin, it has the polyurethane resin which has the sulfonamide group of PU-10-PU-13, and the sulfonamide group and heat-crosslinkable group of PU-31, PU-34, PU-35. A polyurethane resin is particularly preferable.
As a solvent used when synthesizing the polyurethane resin, the same solvent as that used when synthesizing a macromonomer can be used.
The polyurethane resin is synthesized by adding the above-mentioned diisocyanate compound and diol compound in an aprotic solvent and adding a known catalyst having an activity corresponding to the respective reactivity, followed by heating. The molar ratio of the diisocyanate and diol compound to be used is preferably 0.8: 1 to 1.2: 1. If an isocyanate group remains at the end of the polymer, it is finally treated by treatment with alcohols or amines. In the form in which no isocyanate group remains.

Among the copolymer components of the polyurethane resin, the macromonomer content is preferably 5% by weight or more and 95% by weight or less, more preferably 20% by weight or more and 80% by weight or less, and more preferably 40% by weight or more. Most preferably, it is 70 wt% or less.
Further, the molecular weight of the polyurethane suitably used in the present invention is preferably 5,000 to 800,000, more preferably 10,000 to 500,000 in terms of weight average (polystyrene standard), More preferably, it is 20,000-100,000. The dispersity (Mw / Mn) at this time is preferably 20 or less, more preferably 16 or less, and still more preferably 14 or less. When the molecular weight is in the above range, a sufficient effect can be obtained and the developability is excellent.

The content of the polyurethane resin in the photosensitive composition used to form the upper layer is preferably 1 to 30% by weight and more preferably 2 to 20% by weight in terms of solid content.
The content of the polyurethane resin contained in the upper layer is preferably 2 to 99.5% by weight, more preferably 5 to 99% by weight, and 10 to 98% by weight in the total solid content. More preferably.

Furthermore, in the upper layer in the present invention, other resins can be used in combination as long as the effects of the present invention are not impaired. Since the upper layer itself needs to express alkali solubility particularly in the non-image area, it is necessary to select a resin that does not impair this property. From this viewpoint, examples of resins that can be used in combination include water-insoluble and alkali-soluble resins. General water-insoluble and alkali-soluble resins will be described in detail below. Among them, for example, polyamide resins, epoxy resins, polyacetal resins, acrylic resins, methacrylic resins, polystyrene resins, novolac type phenol resins and the like are preferable. be able to.
The amount to be mixed is preferably 50% by weight or less with respect to the polyurethane resin.

<Water-insoluble and alkali-soluble resin>
The lithographic printing plate precursor according to the invention contains a water-insoluble and alkali-soluble resin (hereinafter also simply referred to as “alkali-soluble resin”) in the lower layer.
The alkali-soluble resin that can be used in the present invention is not particularly limited as long as it has a property of dissolving when contacted with an alkaline developer, but contains an acidic group in the main chain and / or side chain in the polymer. It is preferable that the polymer is a homopolymer, a copolymer thereof, or a mixture thereof.
The alkali-soluble resin having such an acidic group preferably has a functional group such as a phenolic hydroxyl group, a carboxy group, a sulfonic acid group, a phosphoric acid group, a sulfonamide group, or an active imide group. Therefore, such a resin can be suitably produced by copolymerizing a monomer mixture containing one or more ethylenically unsaturated monomers having the functional group. Preferred examples of the ethylenically unsaturated monomer having a functional group include, in addition to acrylic acid and methacrylic acid, a compound represented by the following formula and a mixture thereof. In the following formula, R ⁴ represents a hydrogen atom or a methyl group.

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

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

Moreover, as an alkali-soluble resin, a novolak resin is mentioned preferably.
Examples of the novolak resin 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-, or m). Any of-/ p-mixing may be used.) Novolak resins such as mixed formaldehyde resins and pyrogallol acetone resins are preferred.
Furthermore, as described in U.S. Pat. No. 4,123,279, a phenol having an alkyl group having 3 to 8 carbon atoms as a substituent, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin; Examples thereof include condensation polymers with formaldehyde. Moreover, it is preferable that the weight average molecular weight (Mw) is 500 or more, and it is more preferable that it is 1,000-700,000. Moreover, it is preferable that the number average molecular weight (Mn) is 500 or more, and it is more preferable that it is 750-650,000. The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The alkali-soluble resin preferably has a weight average molecular weight of 2,000 or more and a number average molecular weight of 500 or more, a weight average molecular weight of 5,000 to 300,000 and a number average molecular weight of 800 to 250,000. It is more preferable that Moreover, it is preferable that the dispersity (weight average molecular weight / number average molecular weight) of the alkali-soluble resin is 1.1 to 10.
In the lithographic printing plate precursor according to the invention, the alkali-soluble resin may be used alone or in combination of two or more.
The content of the alkali-soluble resin relative to the total solid content of the lower layer in the present invention is preferably used in an addition amount of 50 to 98% by weight. When the addition amount of the alkali-soluble resin is 50% by weight or more, the durability of the recording layer (photosensitive layer) is excellent, and when it is 98% by weight or less, both sensitivity and durability are excellent.

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

Examples of the dye that absorbs at least infrared light or near infrared light include, for example, JP-A-58-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-. Cyanine dyes described in each publication such as 78787, methine dyes described in each publication such as JP-A-58-173696, JP-A-58-181690, JP-A-58-194595, Japanese Laid-Open Patent Publication Nos. 58-112793, 58-224793, 59-48187, 59-73996, 60-52940, 60-63744, etc. Naphthoquinone dyes described in JP-A-58-112792, squarylium dyes described in JP-A-58-112792, cyanine dyes described in British Patent 434,875, etc. Can.
Further, near-infrared absorption sensitizers described in US Pat. No. 5,156,938 are also preferably used as dyes, and substituted arylbenzoates described in US Pat. No. 3,881,924 are also preferred. (Thio) pyrylium salt, trimethine thiapyrylium salt described in JP-A-57-142645 (U.S. Pat. No. 4,327,169), JP-A-58-181051, JP-A-58-2220143, 59-41363, 59-84248, 59-84249, 59-146063, 59-146061, and pyrium compounds described in JP-A-59-216146. Cyanine dye, pentamethine thiopyrylium salt described in U.S. Pat. No. 4,283,475, etc., and Japanese Patent Publication Nos. 5-13514 and 5-19702 Pyrylium compounds disclosed in distribution is, as commercially available products, Epolight III-178 of Eporin Co., Epolight III-130, Epolight III-125 and the like are particularly preferably used.
Another particularly preferable example of the dye is a near-infrared absorbing dye described as formulas (I) and (II) in US Pat. No. 4,756,993.
Particularly preferred dyes are the following cyanine dye A.

The addition amount of the infrared absorber in the lower layer is preferably 0.01 to 50% by weight, more preferably 0.1 to 30% by weight, and more preferably 1.0 to 30% with respect to the total solid content of the lower layer. It is particularly preferred that it is wt%. When the addition amount is 0.01% by weight or more, the sensitivity is lowered, and when it is 50% by weight or less, the uniformity of the layer is good and the durability of the layer is excellent.
Moreover, it is preferable to add an infrared absorber to the upper layer separately from the lower layer. The addition amount of the infrared absorber in the upper layer is preferably 0.01 to 50% by weight, more preferably 0.1 to 30% by weight, and more preferably 1.0 to 30% with respect to the total solid content of the upper layer. It is particularly preferred that it is wt%. When the added amount is 0.01% by weight or more, the sensitivity is excellent, and when it is 50% by weight or less, the uniformity of the upper recording layer is good and the durability of the upper layer is excellent.

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

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

[Surfactant]
The upper layer and / or the lower layer are described in JP-A Nos. 62-251740 and 3-208514 in order to improve the coatability and to increase the stability of processing with respect to development conditions. Such nonionic surfactants, amphoteric surfactants as described in JP-A-59-121044 and JP-A-4-13149, JP-A-62-170950, JP-A-11-288093 And a monomer copolymer containing fluorine as described in JP-A-2003-57820.
Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like.
Specific examples of amphoteric activators include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N-tetradecyl-N, N-betaine. Type (for example, trade name “Amorgen K” manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
The proportion of the surfactant in the total solid content of the lower layer or upper layer is preferably 0.01 to 15% by weight, more preferably 0.01 to 5% by weight, and still more preferably 0.05 to 2.0% by weight.

[Bake-out agent / colorant]
In the upper layer and / or the lower layer, a print-out agent for obtaining a visible image immediately after heating by exposure, or a dye or pigment as an image colorant can be added.
A representative example of the printing-out agent is 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. Examples of the photoacid releasing agent include o-naphthoquinonediazide-4-sulfonic acid halide, and triazine compounds and trihalomethyl compounds as oxazole compounds.
As the colorant, other known dyes can be used in addition to the aforementioned salt-forming organic dyes. Examples of suitable dyes including salt-forming organic dyes include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black BS, Oil Black T-505 (orientated chemistry) Kogyo Co., Ltd.), Victoria Pure Blue, Crystal Violet Lactone, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI42000), Methylene Blue (CI52015), etc. Can do. Further, the dyes described in JP-A-62-293247 are particularly preferred.
These dyes are preferably added at a rate of 0.01 to 10% by weight, more preferably at a rate of 0.1 to 3% by weight, based on the total solid content of the lower or upper layer.

[Plasticizer]
A plasticizer may be added to the upper layer and / or the lower layer in order to impart flexibility or the like of the coating film. For example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid These oligomers and polymers are used.
These plasticizers are preferably added at a rate of 0.5 to 10% by weight, more preferably 1.0 to 5% by weight, based on the total solid content of the lower layer or upper layer.

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

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

In principle, the lower layer and the upper layer are preferably formed by separating two layers.
As a method for forming the two layers separately, for example, a method using a difference in solvent solubility between a component contained in the lower layer and a component contained in the upper layer, or after applying the upper layer, a solvent is rapidly used. For example, a method of drying and removing.
Hereinafter, although these methods are explained in full detail, the method of isolate | separating and apply | coating two layers is not limited to these.

  As a method of utilizing the difference in solvent solubility between the component contained in the lower layer and the component contained in the upper layer, a solvent system in which any of the components contained in the lower layer is insoluble is used when the upper layer coating solution is applied. Is. Thereby, even if it carries out 2 layer application | coating, it becomes possible to isolate | separate each layer clearly and to make a coating film. For example, as the lower layer component, a component insoluble in a solvent such as methyl ethyl ketone or 1-methoxy-2-propanol that dissolves the alkali-soluble resin that is the upper layer component is selected, and the lower layer is applied using a solvent system that dissolves the lower layer component. -It is possible to form two layers by drying and then dissolving the upper layer mainly composed of alkali-soluble resin with methyl ethyl ketone, 1-methoxy-2-propanol, etc., and applying and drying.

  Next, after applying the second layer (upper layer), as a method of drying the solvent very quickly, high-pressure air is blown from a slit nozzle installed substantially perpendicular to the web traveling direction, or heating such as steam is performed. This can be achieved by applying thermal energy as conduction heat from the lower surface of the web from a roll (heating roll) supplied inside the medium, or by combining them.

  Moreover, in order to provide a new function, the upper layer and the lower layer may be partially miscible in a range where the effects of the present invention are sufficiently exhibited. Such a method can be achieved by adjusting the degree in any of the method using the difference in solvent solubility and the method of drying the solvent very quickly after the second layer is applied.

The concentration of the above-described components (total solid content including additives) in the lower layer / upper layer coating solution to be coated on the support is preferably 1 to 50% by weight.
Various methods can be used as the coating method, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating.
In particular, in order to prevent damage to the lower layer during the upper layer coating, the upper layer coating method is preferably a non-contact type. Moreover, although it is a contact type, it is also possible to use bar coater coating as a method generally used for solvent-based coating, but it is preferable to apply by forward driving in order to prevent damage to the lower layer.

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

<Support>
The support used in the lithographic printing plate precursor according to the present invention is not particularly limited as long as it is a dimensionally stable plate having the required strength and durability. For example, paper, plastic (for example, Paper laminated with polyethylene, polypropylene, polystyrene, etc., metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, Cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper on which a metal as described above is laminated or vapor-deposited, or a plastic film.

  Among them, in the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate that has good dimensional stability and is relatively inexpensive is particularly preferable. A suitable aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and may be a plastic film on which aluminum is laminated or vapor-deposited. Examples of foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of foreign elements in the alloy is preferably 10% by weight or less.

Particularly suitable aluminum in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in the refining technique, and may contain slightly different elements.
Thus, the composition of the aluminum plate applied to the present invention is not specified, and an aluminum plate made of a publicly known material can be appropriately used. The thickness of the aluminum plate used in the present invention is preferably 0.1 to 0.6 mm, more preferably 0.15 to 0.4 mm, and particularly preferably 0.2 to 0.3 mm. preferable.

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

The anodizing treatment conditions vary depending on the electrolyte used and cannot be specified in general, but in general, the electrolyte concentration is 1 to 80% by weight solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 60 A / dm ^2. The voltage is preferably in the range of 1 to 100 V and the electrolysis time of 10 seconds to 5 minutes. The amount of the anodized film is preferably 1.0 g / m ² or less. When it is 1.0 g / m ² or less, the printing durability is excellent, the non-image portion of the lithographic printing plate is hardly scratched, and the so-called “scratch stain” in which ink adheres to the scratched portion during printing can be suppressed. it can.
After the anodizing treatment, the aluminum surface is subjected to a hydrophilic treatment if necessary.

  Examples of the hydrophilization treatment used in the present invention include U.S. Pat. Nos. 2,714,066, 3,181,461, 3,280,734, and 3,902,734. There are alkali metal silicate (e.g., aqueous sodium silicate) methods as disclosed in the specification. 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 For example, a method of treating with polyvinylphosphonic acid as disclosed in the literature is used.

<Undercoat layer>
The lithographic printing plate precursor according to the present invention is provided by laminating the lower layer and the upper layer on a support. If necessary, an undercoat layer may be provided between the support and the lower layer. it can.
As an undercoat layer component, various organic compounds are used. For example, phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, 2-aminoethylphosphonic acid, and phenylphosphone which may have a substituent. Acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, organic phosphonic acid such as methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphonic acid, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid optionally having substituents Organic phosphoric acid such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and triethanolamine Hydroxy, such as hydrochloride Hydrochlorides of amines having a are preferably exemplified. These undercoat layer components may be used singly or in combination of two or more.

This organic undercoat layer can be provided by the following method. That is, a method in which a solution obtained by dissolving the above organic compound in 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, and water, methanol, ethanol, methyl ethyl ketone, etc. In this method, an aluminum plate is immersed in a solution obtained by dissolving the above organic compound in an organic solvent or a mixed solvent thereof to adsorb the above compound, and then washed with water and dried to provide an organic undercoat layer. . In the former method, a solution having a concentration of 0.005 to 10% by weight of the organic compound can be applied by various methods. In the latter method, the concentration of the solution is preferably 0.01 to 20% by weight, more preferably 0.05 to 5% by weight, and the immersion temperature is preferably 20 to 90 ° C, more preferably 25 to 50 ° C. The immersion time is preferably 0.1 second to 20 minutes, more preferably 2 seconds to 1 minute. The solution used for this can be adjusted to a pH range of 1 to 12 with basic substances such as ammonia, triethylamine, potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid. A yellow dye can also be added to improve the tone reproducibility of the image recording material.
The coverage of the organic undercoat layer is preferably 2 to 200 mg / m ^2, and more preferably 5 to 100 mg / m ^2. When the coating amount is in the above range, sufficient printing durability can be obtained.
The lithographic printing plate precursor produced as described above is imagewise exposed and then developed.

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

(Plate making method of lithographic printing plate)
The plate making method of the lithographic printing plate of the present invention preferably includes an exposure step for image exposure of the positive lithographic printing plate precursor for infrared laser of the present invention and a development step for developing using a developer in this order. .
The planographic printing plate of the present invention is a planographic printing plate obtained by the plate making method of the planographic printing plate of the present invention.

<Exposure process>
The plate making method of the lithographic printing plate of the present invention preferably includes an exposure step of image-exposing the positive lithographic printing plate precursor for infrared laser of the present invention.
The actinic ray light source used for image exposure of the lithographic printing plate precursor according to the present invention is preferably a light source having an emission wavelength in the near infrared to infrared region, and more preferably a solid laser or a semiconductor laser. Among them, in the present invention, it is particularly preferable that the image exposure is performed by a solid laser or a semiconductor laser that emits infrared rays having a wavelength of 750 to 1,400 nm.
The laser output is preferably 100 mW or more, and a multi-beam laser device is preferably used in order to shorten the exposure time. The exposure time per pixel is preferably within 20 μsec.
The energy applied to the planographic printing plate precursor is preferably 10 to 300 mJ / cm ² . When it is in the above range, curing can proceed sufficiently, laser ablation can be suppressed, and damage to the image can be prevented.

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

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

<Development process>
The plate making method of the lithographic printing plate of the present invention preferably includes a developing step of developing using a developer.
The developer used in the development process (hereinafter also referred to as “processing solution”) is preferably an aqueous solution having a pH of 6 to 13.5, more preferably an alkaline aqueous solution having a pH of 8.5 to 13.5, and a pH of 8.5 to 10 An aqueous alkali solution of .8 is particularly preferred. The developer preferably contains a surfactant, and more preferably contains at least an anionic surfactant or a nonionic surfactant. Surfactant contributes to the improvement of processability.
As the surfactant used in the developer, any of anionic, nonionic, cationic, and amphoteric can be used.
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.

  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 adducts, alkylphenol ethylene oxide adducts, polyethylene glycol adducts of aromatic compounds, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, Higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, oil and fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc. And polyhydric alcohol glycerol fatty acid ester, pentaerythritol fatty acid ester, Rubitoru and fatty acid esters of sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines.

  In the present invention, ethylene oxide adduct of sorbitol and / or sorbitan fatty acid ester, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol More preferred are fatty acid esters and polyethylene glycol adducts of aromatic compounds.

  Moreover, from the viewpoint of stable solubility or turbidity in water, the HLB value is preferably 6 or more, and more preferably 8 or more.

As is well known in the field of surfactants, amphoteric surfactants are compounds having an anionic moiety and a cationic moiety in the same molecule, and are amphoteric such as amino acids, betaines, and amine oxides. A surfactant is included.
As the amphoteric surfactant that can be used in the developer, a compound represented by the following formula <1> and a compound represented by the following formula <2> are preferable.

In formula <1>, R ⁸ represents an alkyl group, R ⁹ and R ¹⁰ each independently represents a hydrogen atom or an alkyl group, R ¹¹ represents an alkylene group, and A represents a carboxylate ion or a sulfonate ion. Represent.
In formula <2>, R ¹⁸ , R ¹⁹ and R ²⁰ each independently represents a hydrogen atom or an alkyl group. However, not all of R ¹⁸ , R ¹⁹ and R ²⁰ are hydrogen atoms.

In the above formula <1>, the alkyl group in R ⁸ , R ⁹ or R ¹⁰ and the alkylene group in R ¹¹ may be linear or branched, and may have a linking group in the chain. In addition, it may further have a substituent. As the linking group, those containing a hetero atom such as an ester bond, an amide bond, or an ether bond are preferable. Moreover, as a substituent, a hydroxyl group, an ethylene oxide group, a phenyl group, an amide group, a halogen atom, etc. are preferable.
In the compound represented by the formula <1>, the total number of carbon atoms of R ^{8 to} R ¹¹ is preferably 8 to 25, and more preferably 11 to 21. Within the above range, the hydrophobic portion is appropriate and the solubility in an aqueous developer is excellent.
It is also possible to increase the solubility of the surfactant in an aqueous developer by adding an organic solvent, for example, a solubilizing agent such as alcohol.

In the above formula <2>, the alkyl group in R ¹⁸ , R ¹⁹ or R ²⁰ may be linear or branched, may have a linking group in the chain, and further has a substituent. You may do it. As the linking group, those containing a hetero atom such as an ester bond, an amide bond, or an ether bond are preferable. Moreover, as a substituent, a hydroxyl group, an ethylene oxide group, a phenyl group, an amide group, a halogen atom, etc. are preferable.
In the compound represented by the formula <2>, the total number of carbon atoms of R ^{18 to} R ²⁰ is preferably 8 to 22, and more preferably 10 to 20. Within the above range, the hydrophobic portion is appropriate and the solubility in an aqueous developer is excellent.

  The total carbon number of the amphoteric surfactant may be affected by the material used for the photosensitive layer, particularly the properties of the binder. In the case of a binder having a high degree of hydrophilicity, those having a relatively small total carbon number are preferred, and when the binder used has a low degree of hydrophilicity, those having a large total carbon number tend to be preferred.

  Preferable specific examples of the amphoteric surfactant that can be used in the developer are shown below, but the present invention is not limited thereto.

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

In order to maintain the developer at pH 6 to 13.5, the presence of carbonate ions and hydrogen carbonate ions as buffering agents can suppress pH fluctuations even when the developer is used for a long period of time. It is possible to suppress development deterioration and development residue generation. 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 bicarbonate 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 is not particularly limited as long as it can be developed, but it is preferably in the range of pH 8.5 to 10.8.

  The total amount of carbonate and bicarbonate is preferably 0.3 to 20% by weight, more preferably 0.5 to 10% by weight, and particularly preferably 1 to 5% by weight based on the total weight of the developer. When the total amount is 0.3% by weight or more, developability and processing capacity do not deteriorate, and when it is 20% by weight or less, it becomes difficult to form precipitates and crystals, and further, during the processing of the waste liquid of the developer, and during neutralization 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. These other alkaline agents are used alone or in combination of two or more.
In addition to the above, the developer may contain a wetting agent, preservative, chelate compound, antifoaming agent, organic acid, organic solvent, inorganic acid, inorganic salt, and the like. However, when a water-soluble polymer compound is added, the plate surface tends to be sticky especially when the developer is fatigued.

  As the wetting agent, ethylene glycol, propylene glycol, triethylene glycol, butylene glycol, hexylene glycol, diethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, diglycerin and the like are preferably used. The wetting agent may be used alone or in combination of two or more. The wetting agent is preferably used in an amount of 0.1 to 5% by weight relative to the total weight of the developer.

  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, pyridine, quinoline, guanidine and other derivatives, diazines, triazole derivatives, oxazoles, oxazine derivatives, nitrobromoalcohol-based 2-bromo-2-nitropropane-1,3diols, 1 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 exhibits a stable effect on bacteria, molds, yeasts, etc., and varies depending on the types of bacteria, molds, yeasts, but is 0% relative to the total weight of the developer. A range of 0.01 to 4% by weight 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 such as phosphonoalkanetricarboxylic acids. An organic amine salt is also effective in place of the sodium salt and potassium salt of the chelating agent. A chelating agent is selected that is stably present in the developer composition and does not impair the printability. The addition amount is preferably 0.001 to 1.0% by weight with respect to the total weight of the developer.

  As the antifoaming agent, a general silicone-based self-emulsifying type, emulsifying type, or nonionic compound can be used, and a compound having an HLB value of 5 or less is preferable. Silicone defoamers 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% by weight with respect to the total weight of the developer.

  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 weight with respect to the total weight of the developer.

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

  Polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, etc.), ketones (methyl ethyl ketone, cyclohexanone, etc.), esters (ethyl acetate, methyl lactate, propylene) Glycol monomethyl ether acetate, etc.) and others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine, N-phenyldiethanolamine, etc.).

  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 weight from the viewpoints of safety and flammability.

  Examples of inorganic acids and inorganic salts include phosphoric acid, metaphosphoric acid, primary ammonium phosphate, secondary ammonium phosphate, primary sodium phosphate, secondary sodium phosphate, primary potassium phosphate, secondary potassium phosphate, Examples thereof include sodium tripolyphosphate, potassium pyrophosphate, sodium hexametaphosphate, magnesium nitrate, sodium nitrate, potassium nitrate, ammonium nitrate, sodium sulfate, potassium sulfate, ammonium sulfate, sodium sulfite, ammonium sulfite, sodium hydrogen sulfate, nickel sulfate and the like. The content of the inorganic salt is preferably 0.01 to 0.5% by weight with respect to the total weight of the developer.

  The development temperature is not particularly limited as long as development is possible, but it is preferably 60 ° C. or lower, more preferably 15 to 40 ° C. In the development processing using an automatic developing machine, the developing solution may be fatigued depending on the processing amount. Therefore, the processing capability may be restored using a replenishing solution or a fresh developing solution. An example of development and post-development processing is a method in which alkali development is performed, alkali is removed in a post-water washing step, gumming is performed in a gumming step, and drying is performed in a drying step. As another example, a method in which pre-water washing, development and gumming are simultaneously performed by using an aqueous solution containing carbonate ions, hydrogen carbonate ions and a surfactant can be preferably exemplified. Therefore, the pre-water washing step is not particularly required, and it is preferable to perform the drying step after performing pre-water washing, development and gumming in one bath only by using one liquid. After development, it is preferable to dry after removing excess developer using a squeeze roller or the like.

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

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 strength of the waist 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, a metal or plastic in which brush materials are implanted in a row, as described in JP-A-58-159533, JP-A-3-100554, or JP-A-62-167253 A brush roll in which the groove mold material is radially wound around a plastic or metal roll as a core without any gap can be used.
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 performs development and gumming in the developing tank 20 and is dried in the drying unit 10.

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

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. Moreover, macromonomer (MM-10-16, MM-21-26, and MM-30-38) and polyurethane resin (PU-11-16, PU-21-26, PU-30-38, PU) -43 to 67, PU-71 to 71, and PU-81 to 87) have the structures described above.

<Synthesis of Macromonomer (MM-10)>
In a three-necked flask equipped with a condenser and a stirrer, 139.55 parts by weight of N- (4-sulfamoylphenyl) methacrylamide, 470 parts by weight of N, N-dimethylacetamide, thioglycerol (Wako Pure Chemical Industries, Ltd.) 15) 70 parts by weight were weighed and heated and stirred at 80 ° C. for 1 hour under a nitrogen flow (50 mL / min). To this reaction solution, 1.337 parts by weight of V-601 (radical polymerization initiator: manufactured by Wako Pure Chemical Industries, Ltd.) was added and stirred at 80 ° C. for 2 hours. Further, V-601 was added to this reaction solution. (Radical polymerization initiator: dimethyl 2,2-azobis (2-methylpropionate), manufactured by Wako Pure Chemical Industries, Ltd.) 1.337 parts by weight were added and stirred at 90 ° C. for 2 hours. The reaction solution was cooled to room temperature to obtain the desired product (MM-10). It was confirmed from the NMR spectrum, IR spectrum, and GPC (polystyrene conversion) that it was the target product. The obtained MM-10 was used for the next reaction without further purification.

<Synthesis of Macromonomer (MM-11-16, MM-21-26, and MM-30-38)>
MM-11-16, MM-21-26, and MM-30-38 were synthesize | combined like the synthesis | combination of MM-10 except having changed the raw material.

<Synthesis of polyurethane resin (PU-10)>
In a three-necked flask equipped with a condenser and a stirrer, 80.52 parts by weight of the reaction solution of MM-10 obtained above, 2,2-bis (hydroxymethyl) propionic acid (manufactured by Tokyo Chemical Industry Co., Ltd.) 6.86 parts by weight was weighed and the reaction solution was adjusted to 50 ° C. to obtain a uniform solution. Millionate MT (Nippon Polyurethane Industry Co., Ltd.) 14.43 parts by weight, 2,4-tolylene diisocyanate (Tokyo Chemical Industry Co., Ltd.) 2.51 parts by weight, Neostan U-600 (Nitto Kasei Co., Ltd.) : Bismuth catalyst) 0.13 parts by weight were added in this order and reacted at 80 ° C. for 4 hours. The reaction solution was poured into 1,500 parts by weight of water to precipitate polyurethane. This was collected by filtration, washed and dried to obtain a binder polymer (PU-10). It was confirmed from the NMR spectrum, IR spectrum, and GPC (polystyrene conversion) that it was the target product.

<Synthesis of polyurethane resins (PU-11-16, PU-21-26, PU-30-38, PU-43-67, PU-71-73, and PU-81-87)>
Except for changing the raw materials, PU-11 to 16, PU-21 to 26, PU-30 to 38, PU-43 to 67, PU-71 to 71, and PU are performed in the same manner as the synthesis of PU-10. -81 to 87 were synthesized.

(Examples 1 to 53, Comparative Examples 1 to 4 and Reference Example 1)
(Production of support)
A JIS A 1050 aluminum plate having a thickness of 0.3 mm was grained with a rotating nylon brush using a pumice-water suspension as an abrasive. The surface roughness (centerline average roughness) at this time was 0.5 μm. After washing with water, a 10% sodium hydroxide aqueous solution was immersed in a solution warmed to 70 ° C., and etching was performed so that the amount of aluminum dissolved was 6 g / m ³ . After washing with water, it was neutralized by immersing in a 30% nitric acid aqueous solution for 1 minute and thoroughly washed with water. Then, electrolytic surface roughening was performed in a 0.7% nitric acid aqueous solution for 20 seconds using a rectangular wave alternating waveform voltage having an anode voltage of 13 volts and a cathode voltage of 6 volts. After dipping to wash the surface, it was washed with water. The roughened aluminum sheet was subjected to a porous anodic oxide film forming treatment using direct current in a 20% aqueous sulfuric acid solution. Electrolysis was performed at a current density of 5 A / dm ² , and the electrolysis time was adjusted to produce a substrate having an anodized film with a weight of 4.0 g / m ^{2 on} the surface. This substrate was treated for 10 seconds in a vapor chamber saturated at 100 ° C. and 1 atm to prepare a substrate (a) having a sealing rate of 60%. The substrate (a) was treated with a 2.5% by weight aqueous solution of sodium silicate at 30 ° C. for 10 seconds to make the surface hydrophilic, and then the following undercoat solution 1 was applied, and the coating film was dried at 80 ° C. for 15 seconds to planographic printing A plate support [A] was obtained. The coating amount of the coating film after drying was 15 mg / m ² .

(Formation of undercoat intermediate layer)
On the support [A] produced as described above, the following coating solution for forming an intermediate layer was applied and then dried at 80 ° C. for 15 seconds to provide an intermediate layer. The coating amount after drying was 15 mg / m ² .

[Undercoat liquid 1]
-0.3 parts by weight of the following copolymer with a molecular weight of 28,000-100 parts by weight of methanol-1 part by weight of water

なお、Ｅｔはエチル基を表し、括弧の右下の数字はモル比を表す。

Et represents an ethyl group, and the number on the lower right of the parenthesis represents a molar ratio.

[Formation of recording layer]
The obtained undercoated support [A] was coated with a photosensitive solution III or a photosensitive solution IV having the following composition with a wire bar, and then dried in a drying oven at 150 ° C. for 40 seconds to obtain a coating amount of 0.8 g / The lower layer was provided so as to be m ² . After providing the lower layer, a photosensitive solution V having the following composition was applied with a wire bar to provide an upper layer. After coating, drying was performed at 150 ° C. for 40 seconds to obtain a photosensitive lithographic printing plate precursor for infrared laser in which the total coating amount of the lower layer and the upper layer was 1.0 g / m ² .

(Photosensitive solution III)
N- (p-aminosulfonylphenyl) methacrylamide / methyl methacrylate / acrylonitrile = 35/35/30 (molar ratio) copolymer (weight average molecular weight 650,000)
3.5 parts by weight · m, p-cresol novolak (m / p ratio = 6/4, weight average molecular weight 6,000)
0.6 part by weight, infrared absorber (IR dye 1) 0.25 part by weight, dye obtained by changing the counter anion of ethyl violet to 6-hydroxy-β-naphthalenesulfonic acid 0.15 part by weight, bisphenol sulfone 0.3 part by weight Parts ・ Tetrahydrophthalic acid 0.4 parts by weight ・ Fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
0.02 part by weight-Methyl ethyl ketone 60 parts by weight-Propylene glycol monomethyl ether 20 parts by weight-Gamma-butyrolactone 20 parts by weight

(Photosensitive solution IV)
-Copolymer of N-phenylmaleimide / methacrylamide / methacrylic acid = 45/35/20 (molar ratio) (weight average molecular weight 50,000) 0.85 parts by weight-Infrared absorber (IR dye 1) 0.25 Parts by weight, ethyl violet 0.05 parts by weight, fluorosurfactant (Megafac F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
0.02 part by weight-Methyl ethyl ketone 5 parts by weight-Propylene glycol monomethyl ether 15 parts by weight-γ-butyrolactone 5 parts by weight

(Photosensitive solution V)
-Polyurethane resin (compound described in Table 1 or Table 2) 1.7 parts by weight-Infrared absorber (IR dye 1) 0.15 parts by weight-Compound Q 0.35 parts by weight-Fluorosurfactant (mega Fuck F-780, manufactured by Dainippon Ink & Chemicals, Inc.)
0.03 parts by weight of a copolymer of tridecafluorooctyl methacrylate / 2-adamantyl acrylate / 2-carboxyethyl methacrylate = 30/50/20, weight average molecular weight 30,000
0.1 part by weight, methyl ethyl ketone 33.0 parts by weight, 1-methoxy-2-propanol 67.0 parts by weight

  REF-2: N-phenylmaleimide / methacrylamide / methacrylic acid = 45/35/20 (molar ratio) copolymer (weight average molecular weight 50,000)

[Evaluation of printing durability]
The obtained lithographic printing plate precursor was drawn with a test pattern in the form of an image by changing the exposure energy with a Trend setter manufactured by Creo. Thereafter, a development processor DT-2 (diluted to a conductivity of 43 mS / cm) and a Fujifilm PS processor LP940H charged with a development temperature of 30 ° C. and a development time of 12 Development was performed in seconds. This was continuously printed using a printer Lithron manufactured by Komori Corporation. At this time, the number of sheets that can be printed while maintaining a sufficient ink density was measured visually to evaluate the printing durability. The printing durability was shown as a relative value when the printing durability of Comparative Example 1 was 1.0. The results are shown in Table 1.

[Evaluation of development latitude]
The obtained lithographic printing plate precursor was imaged in a test pattern using a Trendsetter 3244VX manufactured by Creo at a beam intensity of 9 W and a drum rotation speed of 150 rpm. After that, using an alkali developer having the following composition and having a conductivity changed by changing the dilution rate by changing the amount of water, the solution temperature was changed to 30 using a PS processor 900H manufactured by Fuji Film Co., Ltd. Development was performed at a development time of 22 seconds while maintaining the temperature. At this time, the developer having the highest conductivity and the lowest conductivity of the developer in which the image portion was not eluted and the development was successfully performed without contamination and coloring caused by the poorly developed photosensitive layer residual film. The difference was evaluated as development latitude. The results are shown in Table 1.

[Evaluation of sensitivity]
A test pattern was drawn on the obtained lithographic printing original plate by changing the exposure energy with a Trendsetter 3244VFS manufactured by Creo. Thereafter, in the evaluation of the development latitude, the image portion is not eluted, and the developer having the highest electrical conductivity of the developer that can be satisfactorily developed without being stained or colored due to a poorly developed photosensitive layer residual film; Develop with an alkaline developer having an intermediate (average) conductivity between the lowest one and measure the exposure amount (beam intensity at a drum rotation speed of 160 rpm) that can develop a non-image area with this developer. And sensitivity. The smaller the numerical value, the higher the sensitivity. The results are shown in Table 1.

[Evaluation of shrinkability]
Evaluation similar to the above sensitivity evaluation was performed except that the film was stored for one hour in an environment of 25 ° C. and 70% relative humidity after exposure. Then, by storing the result of the sensitivity evaluation as the sensitivity immediately after the exposure, the degree of decrease in the sensitivity was used as a guideline for the shrinkage. The results are shown in Table 1. In addition, the numerical value of Table 1 represents the sensitivity in 1 hour after exposure, and it is evaluated that the shrinkage is better as the numerical value is closer to the sensitivity immediately after the exposure.

[Evaluation of chemical resistance]
The obtained lithographic printing plate precursor was exposed, developed and printed in the same manner as in the evaluation of printing durability. At this time, each time 5,000 sheets were printed, a process of wiping the plate surface with a cleaner (manufactured by Fuji Film Co., Ltd., multi-cleaner) was added to evaluate chemical resistance. When the printing durability at this time is 95% to 100% of the above-mentioned printing number, 枚 数 is 80% to 95%, △ is 60 to 80%, and 60% or less. X. Even when a process of wiping the plate surface with a cleaner is added, it is evaluated that the change in the printing durability index is excellent in chemical resistance. The results are shown in Table 1 below.

[Developer]
・ D-Sorbit 2.5% by weight
-Sodium hydroxide 0.85% by weight
・ Polyethylene glycol lauryl ether 0.5% by weight
(Weight average molecular weight 1,000)
・ Water 96.15% by weight

  As shown in Table 1, it can be seen that when the polyurethane resin is used as an upper layer, the development latitude and dissolution discriminability (sensitivity) are greatly improved. Further, those having a sulfonamide group in the graft chain of the polyurethane resin were particularly excellent in development latitude, dissolution discrepancy (sensitivity), and chemical resistance.

[Evaluation of printing durability after burning]
The plate surface of a lithographic printing plate obtained by developing in the same manner as in the evaluation of printing durability was washed with water and then wiped with a burning surface-conditioning solution BC-7 manufactured by Fuji Film Co., Ltd., followed by burning at about 270 ° C. for 2 minutes. Processed. Then, it washed with water and processed the plate surface with the liquid which diluted the volume FP-2W made from Fuji Film Co., Ltd. with water twice. After that, as in the evaluation of printing durability, printing was performed using a DIC-GEOS (N) black ink manufactured by Dainippon Ink & Chemicals, Inc. using a Lithrone printing machine manufactured by Komori Corporation. The printing durability after the burning treatment was evaluated by the number of printed sheets when it was visually recognized that the density began to decrease. The printing durability was shown as a relative value when the printing durability of Comparative Example 3 was 1.0.
The results are shown in Table 2.

  As shown in Table 2, it can be seen that when the polyurethane resin is used for the upper layer, the development latitude and dissolution discriminability (sensitivity) are greatly improved. Similar to the results shown in Table 1, those having a sulfonamide group in the graft chain of the polyurethane resin were particularly excellent in development latitude, dissolution discriminability (sensitivity), and chemical resistance. Further, it was found that when a polyurethane resin having a thermally crosslinkable group in the side chain was used, the printing durability after the burning treatment was greatly improved.

(Examples 54 to 86 and Comparative Examples 5 and 6)
<Preparation of lithographic printing plate precursor>
In the same manner as in Example 1, a support, an intermediate layer, a lower layer, and an upper layer were produced. Note that IR dye 1 was used for all infrared absorbers in the photosensitive solution.

<Development process>
Brush roll 1 of an automatic development processor (development tank 25L, plate conveyance speed 100 cm / min, polybutylene terephthalate fiber (hair diameter 200 μm, hair length 17 mm) implanted outer diameter 50 mm) shown in FIG. 1 of the lithographic printing plate precursor after exposure Development was carried out at a temperature of 30 ° C. using a developing solution shown below with a book at 200 revolutions per minute in the same direction as the conveying direction (peripheral speed of brush tip 0.52 m / sec, drying temperature 80 ° C.).

[Developer]
-Water 8963.8 parts by weight-Sodium carbonate 200 parts by weight-Sodium bicarbonate 100 parts by weight-Surfactant (the following compounds listed in Table 3) 656 parts by weight-Ethylenediaminetetraacetic acid tetrasodium (EDTA 4Na) 80 parts by weight- 2-bromo-2-nitropropanediol 0.1 parts by weight 2-methyl-4-isothiazolin-3-one 0.1 parts by weight (pH = 9.7)

SU-1: New Coal B4SN (polyoxyethylene naphthyl ether sulfate, manufactured by Nippon Emulsifier Co., Ltd.)
SU-2: Pionein B-111 (lauryltrimethylammonium chloride, manufactured by Takemoto Yushi Co., Ltd.)
SU-3: New Coal B13 (nonionic surfactant, manufactured by Nippon Emulsifier Co., Ltd.)

  As shown in Table 3, it can be seen that when the polyurethane resin is used for the upper layer, the development latitude and dissolution discriminability (sensitivity) are greatly improved. Further, as in the results of Table 1, those having a sulfonamide group in the graft chain of the polyurethane resin were particularly excellent in development latitude, dissolution discrepancy (sensitivity), and chemical resistance.

  4: lithographic 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 (10)

On the support,
A lower layer containing a water-insoluble and alkali-soluble resin and an infrared absorber;
An upper layer containing a graft copolymer having a sulfonamide group, an active imide group and / or an amide group, and laminated sequentially.
A positive lithographic printing plate precursor for infrared laser, wherein the graft copolymer is a polyurethane resin having a structural unit derived from an ethylenically unsaturated monomer as a graft chain.   The positive type lithographic printing plate precursor for infrared laser according to claim 1, wherein the polyurethane resin is a reaction product of diisocyanate and diol.   The positive lithographic plate for infrared laser according to claim 2, wherein the diol includes a diol (A-1) having a graft chain containing a group selected from the group consisting of a sulfonamide group, an active imide group and an amide group. A printing plate master.   The positive lithographic printing plate precursor for infrared laser according to claim 3, wherein the diol (A-1) has a sulfonamide group.   The diol (A-1) is a radical polymerization of an ethylenically unsaturated monomer having a sulfonamide group, an active imide group and / or an amide group in the presence of a compound having a mercapto group and two hydroxyl groups. The positive lithographic printing plate precursor for infrared laser according to claim 3 or 4, which is the obtained diol compound.   The positive lithographic printing plate precursor for infrared laser according to any one of claims 3 to 5, wherein the diol further comprises a diol (A-2) having a carboxyl group.   The positive lithographic printing plate precursor for infrared laser according to any one of claims 1 to 6, wherein the end of the graft chain is bonded to a diol compound residue via a sulfur atom.   The positive lithographic printing plate precursor for infrared laser according to any one of claims 1 to 7, wherein the upper layer further contains an infrared absorber. An exposure step for image-exposing the positive lithographic printing plate precursor for infrared laser according to any one of claims 1 to 8, and
A plate making method of a lithographic printing plate comprising, in this order, a development step of developing using an alkaline aqueous solution having a pH of 8.5 to 10.8.   The lithographic printing plate making method according to claim 9, wherein the alkaline aqueous solution contains an anionic surfactant or a nonionic surfactant.

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