JP2003107682A - Original plate of planographic printing plate and method for making planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate making method that ensures high sensitivity to infrared laser light and good printing resistance and suppresses contamination by ablation as a plate making method for an IR sensitive original plate of a planographic printing plate capable of direct plate making by recording from digital data of a computer or the like with a solid laser and a semiconductor laser emitting IR. SOLUTION: In the method for making a planographic printing plate, an IR sensitive original plate of a planographic printing plate having an image forming layer on a support comprising (A) an IR absorbent, (B) a radical generator, (C) a radical polymerizable compound, (D) a binder polymer and (E) a UV polymerization initiator having a polymerizable unsaturated group is imagewise exposed with IR, developed and exposed overall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor having sensitivity in an infrared wavelength region, and more specifically, a so-called direct plate-making negative type capable of making a plate directly from a digital signal of a computer or the like using an infrared laser. The present invention relates to a lithographic printing plate precursor and a lithographic printing plate making method.

[0002]

2. Description of the Related Art The development of lasers in recent years has been remarkable, and in particular, solid-state lasers and semiconductor lasers (hereinafter sometimes referred to as "infrared lasers") that emit infrared rays having a wavelength of 760 nm to 1200 nm must have high output and small size. It is now easily available. These infrared lasers are very useful as a recording light source when directly making a printing plate using digital data from a computer or the like. Therefore, in recent years, there has been an increasing demand for an image recording material having a high sensitivity to such an infrared recording light source, that is, an image recording material whose solubility in a developing solution is largely changed by infrared irradiation. As a negative image recording material capable of recording with such an infrared laser, a recording material composed of an infrared absorber, an acid generator, a resole resin and a novolac resin is described in US Pat. No. 5,340,699. However, such a negative-type image recording material requires heat treatment after laser exposure for image formation, and thus a negative-type image recording material that does not require heat treatment after exposure is desired. Was there. Further, in the method using high power density exposure using a high output laser, a large amount of light energy is intensively applied to the exposure area during an instantaneous exposure time,
Light energy is converted into heat energy at a high rate, and the heat causes chemical changes such as chemical changes, phase changes, changes in morphology and structure, and these changes are used for image recording. In the photosensitive layer of the original plate, when the addition amount of the infrared absorbing agent is increased in order to improve the recording sensitivity, the laser exposure device and the light source may be contaminated by ablation (scattering) of the photosensitive layer. In addition, it is also useful to use a photopolymerization system, but because of heat dissipation from the support,
Good printing durability could not be obtained due to insufficient curing near the interface with the support.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an infrared-sensitive lithographic printing plate precursor capable of direct plate making by recording from digital data of a computer or the like using a solid-state laser emitting infrared rays and a semiconductor laser. (EN) A plate-making method having a high sensitivity to an infrared laser, good printing durability, and less contamination due to ablation. Further, an object of the present invention is to enable plate making directly by recording from digital data of a computer or the like using a solid-state laser and a semiconductor laser that emits infrared rays, and it is possible to obtain high printing sensitivity with high sensitivity to an infrared laser. Another object of the present invention is to provide an infrared-sensitive lithographic printing plate precursor which has less contamination due to ablation.

[0004]

[Means for Solving the Problems] The inventors of the present invention have incorporated a photopolymerizable negative type lithographic printing plate precursor capable of directly producing a plate by radiating infrared rays into an ultraviolet polymerization initiator having a polymerizable unsaturated group. It was found that the plate life of the obtained lithographic printing plate was remarkably improved by the plate making method of exposing the whole surface with ultraviolet rays after infrared image exposure and development. In the present invention, the ultraviolet polymerization initiator having a polymerizable unsaturated group is considered to remain without being removed from the image area during development by partly being incorporated into the polymer network at the time of image exposure. It is considered that the ultraviolet polymerization initiator is present in the image area and the effect of the whole surface exposure is remarkably exhibited.

That is, the present invention is as follows: On the support, (A) an infrared absorber, (B) a radical generator, (C) a radically polymerizable compound, (D) a binder polymer and (E) an ultraviolet polymerization initiator having a polymerizable unsaturated group are contained. 1. A plate-making method for a lithographic printing plate, which comprises subjecting a photopolymerizable infrared-sensitive lithographic printing plate precursor having an image forming layer to infrared image exposure, developing and then exposing the whole surface to ultraviolet rays. 2. The plate making method as described in 1 above, wherein the exposure amount at the time of overall exposure is at least equal to the image exposure amount. 3. The plate making method as described in 1 or 2 above, wherein the plate surface temperature is heated to 30 to 150 ° C. during the entire surface exposure. On the support, (A) an infrared absorber, (B) a radical generator, (C) a radically polymerizable compound, (D) a binder polymer and (E) an ultraviolet polymerization initiator having a polymerizable unsaturated group are contained. A lithographic printing plate precursor having an image forming layer.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The plate-making method of the present invention comprises: (A) an infrared absorber, (B) a radical generator, (C) a radically polymerizable compound, (D) a binder polymer, and (E) on a support. An image forming layer containing an ultraviolet polymerization initiator having a polymerizable unsaturated group is used. By subjecting such an image forming layer to imagewise exposure with an infrared laser, the infrared absorbent (A) in the exposed portion undergoes photothermal conversion, and the generated heat decomposes the radical generator (B) to generate radicals. Then, the radicals cure the image forming layer containing the radically polymerizable compound (C) and the binder polymer (D) to form an image portion. After developing this, post-treatment such as desensitizing treatment is arbitrarily performed. To obtain a lithographic printing plate having a surprisingly clear image and having a high printing durability by performing overall exposure with ultraviolet rays at the same exposure amount as the image exposure amount after or before the post-treatment. You can

In the plate making method of the present invention, examples of the light source at the time of overall exposure include a carbon arc lamp, a mercury lamp, a metal halide lamp, a xenon lamp, a tungsten lamp and various laser lights. The exposure amount at the time of whole surface exposure is at least equal to the exposure amount at the time of image exposure before development, more preferably at least 2 times, and further preferably at least 10 times. Furthermore, at least 100 mJ / cm ² or more amount of the entire surface exposure is preferably in order to obtain sufficient printing durability, more preferably 150 mJ / cm ² or more, more preferably, 20
It is 0 mJ / cm ² or more. The light intensity of the light source is 2
It is preferably 0 mW / cm ² or more. Heating may be performed at the same time when the entire surface is exposed, and further improvement in printing durability is recognized by performing heating. Examples of the heating device include a conventional convection oven, IR irradiation device, IR laser, microwave device, Wisconsin oven and the like. At this time, the plate surface temperature is preferably 30 ° C to 150 ° C, more preferably 35 to 130 ° C.
More preferably, it is 40 to 120 ° C.

As a light source for image exposure in the present invention,
A solid-state laser, a semiconductor laser, a thermal head, or the like that emits infrared rays having a wavelength of 760 nm to 1200 nm is used. The laser output is preferably 100 mW or more, and it is preferable to use a multi-beam laser device in order to shorten the exposure time. Also, the exposure time per pixel is 2
It is preferably within 0 μsec. The image exposure amount applied to the recording material is preferably 10 to 500 mJ / cm ² , and more preferably 30 to 300 mJ / cm ² .

The image forming material for forming the image forming layer will be described below. (E) Ultraviolet Polymerization Initiator Having Polymerizable Unsaturated Group First, (E) having a polymerizable unsaturated group contained in the image forming layer of the infrared-sensitive lithographic printing plate precursor, which is a feature of the method of the present invention. The ultraviolet polymerization initiator will be described. This ultraviolet polymerization initiator has a polymerization initiation group that is sensitive to ultraviolet rays. Such a polymerization initiation group is preferably a photopolymerization initiation group having sensitivity to light in the ultraviolet region. Specifically, those having an absorption maximum at 300 to 430 nm are preferable. Examples include benzyls, benzoin ethers, Michler's ketones, anthraquinones, thioxanthones, acridines, phenazines, benzophenones, halomethyltriazine compounds, titanocene compounds, ferrocene compounds, hexaarylbiimidazoles, organics. Examples thereof include peroxides.

The introduction of a polymerizable unsaturated group into these compounds is known in the art, for example, Japanese Patent No. 2736678.
Japanese Patent Laid-Open No. 7-509500, Japanese Patent Laid-Open No. 1-3093
19504, JP-A-5-239117, US Pat. No. 5,248,805, JP-A-6-2117.
It can be carried out by the method described in Japanese Patent No. 58, etc.

The following general formulas (1) to (5) can be given as examples of such compounds. However, none of the general formulas (1) to (5) limits the content of the present invention. First, a [UV polymerization initiator having a polymerizable unsaturated group] having a structure represented by the general formula (1) is shown below.

[0012]

[Chemical 1]

Where A is a group selected from the group consisting of mono-, di- and trihalomethyl groups and Y is-.
_{A, -NH 2, -NHR, -NR} 2, -OR , and -R '
(Here, R is independently a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and R '
Is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted alkenyl group or a substituted polyalkenyl group, a substituted alkynyl group or a substituted polyalkynyl group, and a substituted or unsubstituted heteroaromatic group). Is a group that is In the above group, the substituent is
It is a substituent selected from the group consisting of halogen, alkyl, acyl, arylalkenyl, arylalkynyl, heteroarylalkenyl, and heteroarylalkynyl. In the above definition, preferably, the alkyl group is a C _1-10 alkyl group, the alkenyl group is a C _1-10 alkenyl group, the alkynyl group is a C _1-10 alkynyl group, the acyl group is a C _1-10 acyl group, and an aryl group. it is C _{1 to 12} aryl group, a heteroaryl group is a C _{1 to 1 2} heteroaryl group. Further, L is a linking group or a covalent bond that bonds the triazine nucleus to the compound having a polymerizable unsaturated group, and M is a site having a polymerizable unsaturated group.

To prepare a compound containing -LM, a group having a reactive group, which is useful for a binding reaction with a compound having a polymerizable unsaturated group, and a compound having a polymerizable unsaturated group, are prepared. The group is reacted or polymerized with a group containing a polymerizable group useful for the polymerization reaction. Typical reactive groups useful in coupling or polymerization reactions include hydroxyl; isocyanates; amines; carboxylic acids; anhydrides; vinyl monomers such as acrylates, methacrylates, vinyl esters, acrylamides, methacrylamides, and styrenes; Vinyl esters; and cyclic ethers are included, but are not limited to. Specific examples of the compound having the structure represented by the general formula (1) are shown below. However, these do not limit the content of the present invention.

[0015]

[Chemical 2]

[0016]

[Chemical 3]

However, from the above table, the compound of the present invention
A halomethyl group suitable for ₃Thought to be limited to
You shouldn't. Next, as shown in the general formula (2) below,
Initiate UV polymerization with polymerizable unsaturated groups
Agent].

[0018]

[Chemical 4]

[Wherein R ^a is H, Cl, CN, C _1-4-
Alkyl or phenyl, X is CO-, COO
-, O-CO -, ( CH 2) nY, COO (CH 2) nY,
CO (OCH ₂ CH ₂ ) nY (where n = 1 to 10 and Y is a single bond, —O—, —S—, —CO—, —
COO-, -OCO-, -NH- or -N (C _1-4-
Alkyl)-), m is 0 or 1,
IN is the basic structure of the photoinitiator,

[0020]

[Chemical 5]

(In the formula, R ^b is --CR ³ R ⁴ R ⁵ or --P
(= O) (R ⁶⁾ _2, R ¹ and R ² are H, halogen, C _1-12 - alkyl or C _1-12 - alkoxy, R ³ and R ⁴ are, independently of each other , H, respectively
C _1-12 -alkyl, C _1-12 -alkenyl, C _1-12 -alkoxy or together are C _2-6 -alkylene, R ⁵ is —OH, C _1-6 -alkoxy. , C _1-6 −
Alkanoyloxy, -N (C _1-6 -alkyl) ₂ ,

[0022]

[Chemical 6]

-SO ₂ R ⁷ or -OSO ₂ R ⁷ , R
⁶ is C _1-6 -alkyl, C _1-6 -alkanoyl, phenyl or benzoyl, any of these groups optionally being substituted by halogen, C _1-6 -alkyl or C _1-6 -alkoxy. R ⁷ is C _1-4
-Alkyl or phenyl))

Specific examples of the compound having the structure represented by the general formula (2) are shown below. However, these do not limit the content of the present invention. 4-Vinylphenyl 2-hydroxy-2-propylketone (2a) 4-allyloxyphenyl 2-hydroxy-2-propylketone (2b) 4--2-allyloxyethoxyphenyl 2-hydroxy-2-propylketone (2c) Vinyl 4- (2-hydroxy-2-methylpropionyl) phenoxyacetate (2d) 4-acryloyloxyphenyl 2-hydroxy-2
-Propyl ketone (2e) 4-methacryloyloxyphenyl 2-hydroxy-
2-Propyl ketone (2f) 4-2 acryloyloxyethoxyphenyl 2-hydroxy-2-propyl ketone (2g) 4-2 methacryloyloxyethoxyphenyl 2-
Hydroxy-2-propyl ketone (2h) 4-2 acryloyloxydiethoxyphenyl 2-
Hydroxy-2-propyl ketone (2i) 4-2 acryloyloxyethyl thiophenyl 2-
Hydroxy-2-propylketone (2j) 4-2 acryloyloxyethylthiophenyl 2-
N-morpholino-2-propylketone (2k) 2- [2- (acryloyloxy) ethylthio] thioxanthone (2l) 2- [2- (acryloylamino) ethylthio] thioxanthone (2m) 2- [2- (allyloxy) ethylthio ] Thioxanthone (2n) 2- [2- (allylamino) ethylthio] thioxanthone (2o) 4- [2- (methacryloyloxy) ethoxycarbonyl] thioxanthone (2p)

Next, an [UV polymerization initiator having a polymerizable unsaturated group] having a structure represented by the benzophenone derivative of the general formula (3) is shown below.

[0026]

[Chemical 7]

In the formula, R ¹ , R ² and R ³ may be the same or different and each represents an alkyl group or a cycloalkyl group, R ⁴ represents a hydrogen atom or a methyl group, and n is 3
Represents an integer from 20 to 20. R ¹ and R ² may be bonded to each other to form a ring, or may form a ring condensed with a benzene ring.

In the general formula (3), R ¹ , R ² and R
Of the groups represented by ³ , an alkyl group having 1 to 20 carbon atoms and a cycloalkyl group having 5 to 12 carbon atoms are preferable. Of these, an alkyl group having 2 to 8 carbon atoms is preferable, and specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, and an octyl group are preferable. When R ¹ and R ² form a ring, a 5- to 7-membered ring containing a nitrogen atom is preferable. When R ¹ and R ² form a ring condensed with a benzene ring, those represented by the following formulas are preferable.

[0029]

[Chemical 8]

In the general formula (3), 3 is particularly preferable among the integers represented by n, and in this case, the carbon chain represents (CH ₂ ) ₃ . Specific examples of the compound having the structure represented by the general formula (3) are shown below, but the invention is not limited thereto.

[0031]

[Chemical 9]

[0032]

[Chemical 10]

[0033]

[Chemical 11]

[0034]

[Chemical 12]

[0035]

[Chemical 13]

The [ultraviolet polymerization initiator having a polymerizable unsaturated group] having the structure represented by the general formula (4) is shown below.

[0037]

[Chemical 14]

[In the formula, X ⁻ represents one equivalent of anion;
R ⁵ represents a hydrogen atom or a methyl group; each R ⁴ independently represents a methyl or ethyl group, and R ¹ , R ² and R
Each of the ³ is independently a hydrogen or halogen atom, 1
An alkyl, alkoxy or alkylthio group having 4 to 4 carbon atoms, an arylthio group or the following formula (4-
1):

[0039]

[Chemical 15] (Wherein R ⁴ , R ⁵ and X ⁻ have the meanings given above). The arylthio group can be, for example, a p-toluylthio group. Preferably R ¹ , R ² and R
Each of ³ is independently a hydrogen atom, a halogen atom, 1 to
An alkyl or alkoxy group having 4 carbon atoms or a group of formula (4-1) is shown. More preferably, R ² and R ³ both represent a hydrogen atom and R ¹ is a hydrogen atom,
A halogen atom, an alkyl or alkoxy group having 1 to 4 carbon atoms or a group of formula (4-1) is shown. Particularly preferably, R ² and R ³ represent a hydrogen atom and R ¹ represents a hydrogen atom, a chlorine atom, a methoxy group or a tert-butyl group. Preferably each R ⁴ represents a methyl group. Preferably R ⁵
Represents a hydrogen atom. Preferably X ⁻ is a halogen ion,
For example, chlorine ion or more preferably bromine ion. In the compound of the general formula (4), the group represented by the formula (4-1) can be present in the ortho, meta or para position with respect to the benzoyl group. Preferably this group is in the para position. Preferably the group R ¹ is in the para position relative to the benzoylcarbonyl group.

Specific compounds include 4-benzoyl-N, N-dimethyl-N- (2- (1-oxo-2-propenyloxy) ethyl) benzenemethanaminium bromide and 4-benzoyl-N, N. -Dimethyl-N-
(2- (2-Methyl-1-oxo-2-propenyloxy) ethyl) benzenemethaneaminium chloride, 3
-Benzoyl-N, N-dimethyl-N- (2- (1-oxo-2-propenyloxy) ethyl) benzenemethanaminium bromide, 4- (4-chlorobenzoyl)
-N, N-dimethyl-N- (2- (1-oxo-2-propenyloxy) ethyl) benzenemethanaminium bromide, 4- (4-methoxybenzoyl) -N, N-
Dimethyl-N- (2- (1-oxo-2-propenyloxy) ethyl) benzenemethanaminium bromide,
4- (4-tert-butylbenzoyl) -N, N-dimethyl-N- (2- (1-oxo-2-propenyloxy) ethyl) benzenemethanaminium bromide and the like can be mentioned. It is not limited by these.

[0041]

[Chemical 16]

In the formula, R ^{1 to} R ⁴ represent an alkyl group or an aryl group, and Ar represents an aryl group. R ¹ and R ² or R ³ and R ⁴ may combine with each other to form a ring. Z
Represents a hydrocarbon-containing linking group which may have a divalent substituent.

[0043]

[Chemical 17]

2 containing at least one group represented by
Represents a valent linking group or a single bond. Here, R ⁵ represents a hydrogen atom, a hydrocarbon group which may have a substituent or may contain an unsaturated bond, a carbonyl group or a sulfonyl group. R ^{5 to} R ⁸ are the same or different from each other and represent a hydrocarbon group which may have a substituent or may contain an unsaturated bond. T ⁻ represents a monovalent anion composed of a halogen atom or a monovalent sulfonate anion. X is a group having an addition-polymerizable group represented by the following formula (5-a).

[0045]

[Chemical 18]

And r ^{1 to} r ³ are the same or different from each other and represent a hydrogen atom, a methyl group, an ethyl group, a phenyl group, a halogen atom, a cyano group or —C (═O) —OR ⁹ .
n represents 0 or 1. However, when n is 0, all of r ^{1 to} r ³ are not hydrogen atoms. r ⁴ and r ⁵ are the same or different from each other and represent a hydrogen atom, a methyl group, an ethyl group or a phenyl group. R ⁹ represents an alkyl group or an aryl group. Examples of compounds are shown below, but the invention is not limited thereto.

[0047]

[Chemical 19]

[0048]

[Chemical 20]

[0049]

[Chemical 21]

[0050]

[Chemical formula 22]

For each of the other components of the image forming layer,
This will be explained sequentially. (A) Infrared absorber The object of the present invention is to record an image with a laser emitting infrared rays. For this purpose, it is essential to use (A) infrared absorber. The infrared absorber has a function of converting the absorbed infrared rays into heat. The heat generated at this time decomposes the radical generator to generate radicals.
The infrared absorbent used in the present invention has a wavelength of 760.
It is a dye or pigment having an absorption maximum from nm to 1200 nm.

As the dye, commercially available dyes and known dyes described in documents such as "Dye Handbook" (edited by the Society of Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinone imine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, and metal thiolate complexes. Is mentioned.

Preferred dyes include, for example, JP-A-5
Cyanine dyes described in JP-A No. 8-125246, JP-A-59-84356, JP-A-59-202829, JP-A-60-78787, and JP-A-58-1736.
96, JP-A-58-181690, JP-A-58-1
Methine dyes described in Japanese Patent Application No. 94595, JP-A-Sho 5
8-112793, JP-A-58-224793, JP-A-59-48187, JP-A-59-73996,
Naphthoquinone dyes described in JP-A-60-52940, JP-A-60-63744 and the like, JP-A-58-1
Squarylium dyes described in No. 12792,
Examples thereof include cyanine dyes described in British Patent 434,875.

The near infrared absorption sensitizer described in US Pat. No. 5,156,938 is also preferably used, and the substituted arylbenzo (thio) described in US Pat. No. 3,881,924 is also used. Pyrylium salt, JP-A-57-142645
Trimethine thiapyrylium salt described in U.S. Pat. No. 4,327,169, JP-A Nos. 58-181051, 58-220143, 59-41363 and 59-11363.
-84248, 59-84249, 59-14
Nos. 6063 and 59-146061, pyranium compounds described in JP-A-59-216146, pentamethine thiopyrylium salts described in U.S. Pat. No. 4,283,475, and the like. Fair 5-13
The pyrylium compounds disclosed in Nos. 514 and 5-19702 are also preferably used.

Another preferred example of the dye is represented by the formula (I) in US Pat. No. 4,756,993:
The near infrared absorbing dye described as (II) can be mentioned. Of these dyes, particularly preferred are cyanine dyes, squarylium dyes, pyrylium salts, and nickel thiolate complexes. further,
Cyanine dyes are preferable, and cyanine dyes represented by the following general formula (I) are most preferable.

[0056]

[Chemical formula 23]

In the general formula (I), X ¹ is a halogen atom,
Alternatively, it represents X ² -L ¹ . Here, X ² represents an oxygen atom or a sulfur atom, and L ¹ represents a hydrocarbon group having 1 to 12 carbon atoms. R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. From the viewpoint of storage stability of the coating liquid for the image forming layer, R ¹ and R ² are preferably a hydrocarbon group having 2 or more carbon atoms, and further R ¹
And R ² are particularly preferably bonded to each other to form a 5-membered ring or a 6-membered ring.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Examples of preferable substituents include a hydrocarbon group having 12 or less carbon atoms, a halogen atom, and an alkoxy group having 12 or less carbon atoms. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ^{4, which} may be the same or different, each represents a hydrocarbon group having 20 or less carbon atoms, which may have a substituent. As a preferable substituent, an alkoxy group having 12 or less carbon atoms,
Examples thereof include a carboxyl group and a sulfo group. R ⁵ , R ⁶ , R
⁷ and R ⁸ may be the same or different,
It represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, hydrogen atom is preferable. Z ¹⁻ represents a counter anion. However, when any of R ^{1 to} R ⁸ is substituted with a sulfo group, Z ^1- is not necessary. Preferred Z ¹⁻ is a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion from the storage stability of the coating solution for the image forming layer, and particularly preferably,
Perchlorate ion, hexafluorophosphate ion, and aryl sulfonate ion.

Specific examples of the cyanine dye represented by formula (I) which can be preferably used in the present invention include paragraph [0] of JP-A No. 2001-133969.
Examples thereof include those described in [017] to [0019].

The pigment used in the present invention includes:
Commercial pigment and color index (CI) handbook,
"Latest Pigment Handbook" (edited by Japan Pigment Technology Association, 1977), "Latest Pigment Application Technology" (CMC Publishing, 1986), "Printing Ink Technology" CMC Publishing, 1984)
The pigments described in 1. can be used.

The types of pigments include black pigments, yellow pigments, orange pigments, brown pigments, red pigments, purple pigments,
Blue pigment, green pigment, fluorescent pigment, metal powder pigment, etc.
Polymer bound dyes may be mentioned. Specifically, insoluble azo pigments, azo lake pigments, condensed azo pigments, chelate azo pigments, phthalocyanine pigments, anthraquinone pigments,
Perylene and perinone pigments, thioindigo pigments, quinacridone pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, dyed lake pigments,
Azine pigment, nitroso pigment, nitro pigment, natural pigment, fluorescent pigment, inorganic pigment, carbon black and the like can be used.
Preferred among these pigments is carbon black.

These pigments may be used without surface treatment or may be used after surface treatment. The surface treatment method includes a method of surface-coating a resin or wax, a method of attaching a surfactant, a method of binding a reactive substance (for example, a silane coupling agent, an epoxy compound, polyisocyanate, etc.) to the pigment surface, etc. Can be considered. The above surface treatment method is "property and application of metal soap" (Koushobo),
It is described in "Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986).

The particle size of the pigment is preferably in the range of 0.01 μm to 10 μm, more preferably in the range of 0.05 μm to 1 μm, and particularly preferably 0.1 μm to 1 μm.
It is preferably in the range of. Particle size of pigment is 0.01μ
When it is less than m, it is not preferable from the viewpoint of stability of the dispersion in the coating solution for the image forming layer, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the image forming layer.

As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production, etc. can be used. Examples of the disperser include an ultrasonic disperser, a sand mill, an attritor, a pearl mill, a super mill, a ball mill, an impeller, a disperser, a KD mill, a colloid mill, a dynatron, a three-roll mill and a pressure kneader. For details, see "Latest Pigment Application Technology" (CMC Publishing, 1
986).

These infrared absorbers may be added to the same layer as other components, or may be added to another layer provided, but when the negative lithographic printing plate precursor is prepared The optical density at the absorption maximum in the wavelength range of 760 nm to 1200 nm of the image forming layer is preferably 0.1 to 3.0. If it is out of this range, the sensitivity tends to be low. Since the optical density is determined by the amount of the infrared absorber added and the thickness of the recording layer, the predetermined optical density can be obtained by controlling both conditions. The optical density of the recording layer can be measured by a conventional method. As a measuring method, for example, a transparent or white support, a coating amount after drying to form a recording layer having a thickness appropriately determined in the range necessary for a lithographic printing plate, with a transmission type optical densitometer Examples thereof include a measuring method and a method of forming a recording layer on a reflective support such as aluminum and measuring the reflection density.

(B) Radical generator The (B) radical generator used in the present invention is 3
A compound that has an absorption maximum at a wavelength shorter than 00 nm and is used in combination with (A) an infrared absorbing agent to generate a radical when irradiated with an infrared laser. Examples of the radical generator include an onium salt, a peroxide, an azo-based polymerization initiator, an azide compound, a quinonediazide, and the onium salt is preferable because it has high sensitivity. The onium salt that can be preferably used as the radical polymerization initiator in the present invention will be described. Preferred onium salts include iodonium salts, diazonium salts and sulfonium salts. In the present invention, these onium salts function not as an acid generator but as an initiator of radical polymerization. The onium salt preferably used in the present invention has the following general formula (II
It is an onium salt represented by I) to (V).

[0067]

[Chemical formula 24]

In the formula (III), Ar ¹¹ and Ar ¹² each independently have 20 carbon atoms which may have a substituent.
Not more than 10 aryl groups are shown. When the aryl group has a substituent, a preferable substituent is a halogen atom,
Nitro group, alkyl group having 12 or less carbon atoms, alkoxy group having 12 or less carbon atoms, or 12 carbon atoms
Up to and including 4 aryloxy groups. Z ^{11 −} represents a counter ion selected from the group consisting of a halogen ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, and preferably a perchlorate ion and a hexafluorophosphate ion. An ion and an aryl sulfonate ion.

In the formula (IV), Ar^{twenty one}Has a substituent
It represents an aryl group having 20 or less carbon atoms which may be present.
Preferred substituents are halogen atom, nitro group, carbon
Alkyl group with 12 or less elementary atoms, 12 or less carbon atoms
The lower alkoxy group, arylo having 12 or less carbon atoms
Xy group, alkylamino group having 12 or less carbon atoms, charcoal
Dialkylamino group having 12 or less elementary atoms, number of carbon atoms
12 or less arylamino groups or 12 carbon atoms
Up to and including 4 diarylamino groups. Z ^{twenty one-}Is Z
^11-Represents a counter ion having the same meaning as.

In the formula (V), R ³¹ , R ³² and R ^{33, which} may be the same or different, each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include a halogen atom, a nitro group, an alkyl group having 12 or less carbon atoms, an alkoxy group having 12 or less carbon atoms, or an aryloxy group having 12 or less carbon atoms. Z ^31- represents a counter ion having the same ^meaning as Z ^11- .

In the present invention, specific examples of the onium salt which can be preferably used as the radical generator include:
Paragraph number [003 of JP 2001-133969 A
[0] to [0033] may be mentioned.

The maximum absorption wavelength of the radical generator used in the present invention is preferably 400 nm or less, more preferably 360 nm or less. By thus setting the absorption wavelength in the ultraviolet region, the lithographic printing plate precursor can be handled under a white light.

These radical generators are contained in an amount of 0.1 to 50% by mass, preferably 0.5 to 30% by mass, and particularly preferably 1 to 20% by mass, based on the total solid content of the coating liquid for the image forming layer. It can be added to the coating solution for the image forming layer. If the amount added is less than 0.1% by mass, the sensitivity will be low, and if it exceeds 50% by mass, stains will occur on the non-image area during printing. These radical generators may be used alone or in combination of two or more. Further, these radical generators may be added to the same layer as other components,
Another layer may be provided and added to it.

(C) Radical Polymerizable Compound The radical polymerizable compound (C) used in the present invention is a radical polymerizable compound having at least one ethylenically unsaturated double bond, and has a terminal ethylenically unsaturated bond. Is selected from compounds having at least one, and preferably two or more. Such a compound group is widely known in the industrial field, and these compounds can be used in the invention without particular limitation. These have a chemical form such as a monomer, a prepolymer, that is, a dimer, a trimer and an oligomer, or a mixture thereof and a copolymer thereof. Examples of the monomers and copolymers thereof include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), and their esters and amides. As the ester, an ester of an unsaturated carboxylic acid and an aliphatic polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and an aliphatic polyhydric amine compound are used.
Further, unsaturated carboxylic acid esters having a nucleophilic substituent such as a hydroxyl group, an amino group and a mercapto group, monofunctional or polyfunctional isocyanates with amides, addition reaction products with epoxies, monofunctional or polyfunctional, or A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Also,
Addition reaction products of unsaturated carboxylic acid esters or amides having an electrophilic substituent such as an isocyanate group or an epoxy group with monofunctional or polyfunctional alcohols, amines and thiols, and halogen groups or A substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine and thiol is also suitable. Further, as another example, it is also possible to use a compound group in which unsaturated phosphonic acid, styrene or the like is substituted for the above unsaturated carboxylic acid.

Specific examples of acrylic acid ester, methacrylic acid ester, itaconic acid ester, crotonic acid ester, isocrotonic acid ester and maleic acid ester which are radical polymerizable compounds which are esters of an aliphatic polyhydric alcohol compound and an unsaturated carboxylic acid. An example is JP-A-2001-
Paragraph Nos. [0037] to [004 of Japanese Patent No. 133969
2], and these can also be applied to the present invention.

Examples of other esters include, for example, Japanese Examined Patent Publication Nos. 46-27926 and 51-47334,
The aliphatic alcohol-based esters described in JP-A-57-196231 and the aromatic skeletons described in JP-A-59-5240, JP-A-59-5241 and JP-A-2-226149 are used. Having, JP-A-1-16561
Those containing an amino group described in JP-A No. 3 are also preferably used.

Specific examples of the amide monomer of an aliphatic polyvalent amine compound and an unsaturated carboxylic acid include methylenebis-acrylamide, methylenebis-methacrylamide, 1,6-hexamethylenebis-acrylamide, 1,6- Hexamethylene bis-methacrylamide,
Examples include diethylenetriamine tris acrylamide, xylylene bis acrylamide, and xylylene bis methacrylamide. Examples of other preferable amide-based monomers include those having a cyclohexylene structure described in JP-B No. 54-21726.

Further, a urethane-based addition-polymerizable compound produced by addition reaction of isocyanate and hydroxyl group is also suitable, and specific examples thereof include, for example, Japanese Examined Patent Publication No.
In a molecule obtained by adding a vinyl monomer having a hydroxyl group represented by the following formula (VI) to a polyisocyanate compound having two or more isocyanate groups in one molecule described in JP-A-8-41708, Examples thereof include vinyl urethane compounds containing one or more polymerizable vinyl groups.

General formula (VI) CH ₂ = C (R ⁴¹ ) CO
OCH ₂ CH (R ⁴² ) OH (provided that R ⁴¹ and R
⁴² represents H or CH ₃ . )

Further, urethane acrylates such as those described in JP-A-51-37193, JP-B-2-32293 and JP-B-2-16765, and JP-B-58-
49860, Japanese Patent Publication No. 56-17654, Japanese Patent Publication No. 62
The urethane compounds having an ethylene oxide skeleton described in JP-B-39417 and JP-B-62-39418 are also suitable.

Further, radically polymerizable compounds having an amino structure or a sulfide structure in the molecule, which are described in JP-A-63-277653, JP-A-63-260909 and JP-A-1-105238, may be used. good.

Another example is JP-A-48-641.
No. 83, Japanese Patent Publication No. 49-43191, Japanese Patent Publication No. 52-30
Polyfunctional acrylates and methacrylates such as polyester acrylates and epoxy acrylates obtained by reacting an epoxy resin with (meth) acrylic acid as described in Japanese Patent No. 490 and each publication can be given. Also,
JP-B-46-43946, JP-B1-40337,
Specific unsaturated compounds described in JP-B-1-40336,
The vinylphosphonic acid compounds described in JP-A-2-25493 can also be used. In some cases, the structure containing a perfluoroalkyl group described in JP-A-61-22048 is preferably used. Furthermore, the Japan Adhesive Association magazine, vol. 20, No. 7, pages 300-308 (1
Those introduced as photo-curable monomers and oligomers in (984) can also be used.

Regarding these radically polymerizable compounds,
The details of the method of use, such as what kind of structure is used, whether it is used alone or in combination, and how much is added, can be arbitrarily set according to the performance design of the final recording material. For example, it is selected from the following viewpoints. In terms of sensitivity, a structure having a large amount of unsaturated groups per molecule is preferable, and in many cases, a bifunctional or higher functional group is preferable. Further, in order to increase the strength of the image area, that is, the cured film, a compound having a trifunctional or higher functionality is preferable, and further, a compound having different functional numbers and different polymerizable groups (for example, an acrylic ester compound, a methacrylic ester compound Compounds, styrenic compounds, etc.) are used in combination to control both photosensitivity and strength. Large molecular weight compounds and highly hydrophobic compounds have excellent sensitivity and film strength, but
It may not be preferable in terms of development speed and precipitation in a developing solution. In addition, the compatibility and dispersibility with other components in the image forming layer (for example, binder polymer, initiator, colorant, etc.) are important factors in selecting and using the radical polymerization compound. In some cases, the compatibility may be improved by using a low-purity compound or using two or more compounds in combination. In addition, a specific structure may be selected for the purpose of improving the adhesiveness of the support, the overcoat layer and the like. Regarding the blending ratio of the radical-polymerizable compound in the image recording layer, the larger the amount, the more advantageous in terms of sensitivity. However, if the amount is too large, undesired phase separation may occur or the adhesiveness of the image recording layer may affect the production process. May occur (for example, transfer of recording layer components, manufacturing failure due to adhesion), or precipitation from a developing solution. From these viewpoints, in many cases, the preferable compounding ratio of the radically polymerizable compound is 5 to 80% by mass, preferably 20 to 75% by mass based on all the components of the composition. These may be used alone or in combination of two or more. In addition, the method of using the radically polymerizable compound, the degree of inhibition of polymerization with respect to oxygen, resolution, fogging, refractive index change, surface tackiness, etc., an appropriate structure, formulation, and addition amount can be arbitrarily selected. Depending on the case, a layer constitution / coating method such as undercoating or topcoating can be carried out.

(D) Binder Polymer In the present invention, (D) binder polymer is further used. A linear organic polymer is preferably used as the binder polymer. Any of these "linear organic polymers" may be used. A linear organic polymer that is soluble or swellable in water or weak alkaline water is preferably selected to enable water development or weak alkaline water development. Linear organic polymers are
It is selected and used not only as a film forming agent for forming an image forming layer but also as a developer for water, weak alkaline water or an organic solvent. For example, water development becomes possible by using a water-soluble organic polymer. Examples of such linear organic polymers include radical polymers having a carboxylic acid group in the side chain, for example, JP-A-59-44615, JP-B-54-34327, JP-B-58-12577, and JP-B-54-25957. No. JP-A-54-92723,
Those described in JP-A-59-53836 and JP-A-59-71048, that is, methacrylic acid copolymers, acrylic acid copolymers, itaconic acid copolymers, crotonic acid copolymers, maleic acid Examples thereof include copolymers and partially esterified maleic acid copolymers. Similarly, there is an acidic cellulose derivative having a carboxylic acid group in its side chain. In addition to these, it is useful to add a cyclic acid anhydride to a polymer having a hydroxyl group.

Of these, a (meth) acrylic resin having a benzyl group or an allyl group and a carboxyl group in its side chain is particularly preferable because it has an excellent balance of film strength, sensitivity and developability.

Further, Japanese Patent Publication No. 7-2004, Japanese Patent Publication No. 7-2004
-120041, Japanese Patent Publication No. 7-120042, Japanese Patent Publication No. 8-12424, Japanese Patent Laid-Open No. 63-287944, Japanese Patent Laid-Open No. 63-287947, Japanese Patent Laid-Open No. 1-271741,
The urethane-based binder polymer containing an acid group described in JP-A No. 11-352691, etc., is very excellent in strength and is advantageous in terms of printing durability and low exposure suitability.

In addition to these, polyvinylpyrrolidone and polyethylene oxide are useful as the water-soluble linear organic polymer. Further, alcohol-soluble nylon, polyether of 2,2-bis- (4-hydroxyphenyl) -propane and epichlorohydrin, etc. are also useful for increasing the strength of the cured film.

The weight average molecular weight of the polymer used in the present invention is preferably 5,000 or more, more preferably 10,000 to 300,000, and the number average molecular weight is preferably 1,000 or more, further preferably. Is in the range of 2000 to 250,000. The polydispersity (weight average molecular weight / number average molecular weight) is preferably 1 or more, more preferably 1.1 to 10. These polymers may be random polymers, block polymers, graft polymers, etc., but are preferably random polymers.

The polymer used in the present invention can be synthesized by a conventionally known method. As the solvent used in the synthesis, for example, tetrahydrofuran, ethylene dichloride, cyclohexanone, methyl ethyl ketone, acetone, methanol, ethanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, diethylene glycol dimethyl ether, 1-methoxy -2-propanol, 1-methoxy-2-propyl acetate, N, N-
Dimethylformamide, N, N-dimethylacetamide, toluene, ethyl acetate, methyl lactate, ethyl lactate,
Dimethyl sulfoxide, water, etc. may be mentioned. These solvents may be used alone or in admixture of two or more. As the radical polymerization initiator used when synthesizing the polymer used in the present invention, known compounds such as an azo initiator and a peroxide initiator can be used.

The binder polymers used in the present invention may be used alone or in combination. These polymers are 20 to 95% by mass, preferably 30 to 90% by mass, and more preferably 40% by mass based on the total solid content of the coating liquid for the image forming layer.
It is added to the image forming layer in a proportion of 85% by mass. If the addition amount is less than 20% by mass, the strength of the image area will be insufficient when an image is formed. If the addition amount exceeds 95% by mass, no image is formed. The weight ratio of the compound having a radical-polymerizable ethylenically unsaturated double bond and the linear organic polymer is preferably 1/9 to 7/3.

[Other Components of Image Forming Layer] In the present invention, various compounds other than these may be added if necessary. For example, a dye having a large absorption in the visible light region can be used as a colorant for images. Specifically, Oil Yellow # 101 and Oil Yellow # 10
3, oil pink # 312, oil green BG, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-50
5 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI4255
5), methyl violet (CI42535), ethyl violet, rhodamine B (CI145170B),
Malachite green (CI42000), methylene blue (CI52015), etc., and JP-A-62-29324.
The dyes described in No. 7 can be mentioned. Further, pigments such as phthalocyanine-based pigments, azo-based pigments, carbon black and titanium oxide can also be preferably used.

It is preferable to add these colorants because the image area and the non-image area can be easily distinguished after the image formation. The addition amount is 0.01 to 10% by mass based on the total solid content of the coating liquid for the image forming layer.

Further, in the present invention, a small amount of thermal polymerization is carried out in order to prevent unnecessary thermal polymerization of the radically polymerizable compound having an ethylenically unsaturated double bond during preparation or storage of the coating solution for the image forming layer. It is desirable to add an inhibitor. Suitable thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4'-thiobis (3-methyl-6-t-).
Butylphenol), 2,2'-methylenebis (4-methyl-6-t-butylphenol), N-nitroso-N
-Phenylhydroxylamine aluminum salt and the like. The addition amount of the thermal polymerization inhibitor is preferably about 0.01 mass% to about 5 mass% with respect to the weight of the entire composition. Further, if necessary, a higher fatty acid derivative such as behenic acid or behenic acid amide may be added to prevent polymerization inhibition by oxygen, and may be unevenly distributed on the surface of the image forming layer during the drying process after coating. Good. The amount of the higher fatty acid derivative added is preferably about 0.1% by mass to about 10% by mass of the total composition.

Further, in the coating solution for the image forming layer in the present invention, in order to broaden the stability of the treatment against the developing conditions, a non-coating solution as described in JP-A-62-251740 and JP-A-3-208514 is used. Ionic surfactant, JP-A-5
Amphoteric surfactants such as those described in JP-A-9-121044 and JP-A-4-13149 can be added.

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 the amphoteric surfactant include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, N-tetradecyl-N, N-. Betaine type (for example,
Examples of the brand name include Amogen K, manufactured by Daiichi Kogyo Co., Ltd. The ratio of the nonionic surfactant and the amphoteric surfactant in the coating liquid for the image forming layer is 0.05 to 15% by mass.
Is preferable, and more preferably 0.1 to 5 mass%.

Further, a plasticizer is added to the coating liquid for the image forming layer according to the present invention, if necessary, in order to impart flexibility to the coating film. For example, polyethylene glycol,
Tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate and the like are used.

To produce the planographic printing plate precursor of the invention,
Usually, each of the above components required for the image forming layer coating solution may be dissolved in a solvent and coated on a suitable support. As the solvent used here, 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. Ethane, methyl lactate, ethyl lactate,
Examples thereof include N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, sulfolane, γ-butyl lactone, toluene and water, but are not limited thereto. Absent. These solvents are used alone or as a mixture. The concentration of the above components (total solids including additives) in the solvent is preferably 1 to 50% by mass.

The coating amount (solid content) of the image-forming layer on the support obtained after coating and drying varies depending on the use,
As for the lithographic printing plate precursor, it is generally 0.5 to 5.0.
g / m ² is preferred. Various methods can be used for coating, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating, and roll coating. As the coating amount decreases,
Although the apparent sensitivity is high, the film properties of the image forming layer that functions as an image recording are deteriorated.

The coating solution for the image forming layer according to the present invention contains a surfactant for improving the coating property, such as JP-A-62-162.
Fluorosurfactants such as those described in 170950 can be added. The preferable addition amount is 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass, based on the solid content of the material of all the image forming layers.

[Overcoat Layer] An oxygen-blocking overcoat layer may be provided on the photopolymerizable layer in order to block oxygen that inhibits polymerization of the photopolymerizable layer. As the overcoat layer, a thin film of an oxygen barrier polymer such as cellulose, polyvinyl alcohol and its derivatives, polyester, or polyvinylidene fluoride can be provided.

[Support] The negative image-forming material according to the method of the present invention is formed by coating the above-mentioned image-forming layer on a support. The support that can be used here is not particularly limited as long as it is a dimensionally stable plate-like material, and examples thereof include paper, paper laminated with plastic (for example, polyethylene, polypropylene, polystyrene, etc.), metal plate ( For example,
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 or plastic film laminated or vapor-deposited with the above metals, and the like. A preferable support includes a polyester film or an aluminum plate.

As the support used in the lithographic printing plate precursor according to the invention, it is preferable to use an aluminum plate which is lightweight and has excellent surface processability, processability and corrosion resistance. The aluminum material used for this purpose is JIS 1050.
Material, JIS 1100 material, JIS 1070 material, Al-
Examples thereof include Mg-based alloys, Al-Mn-based alloys, Al-Mn-Mg-based alloys, Al-Zr-based alloys, and Al-Mg-Si-based alloys.

The preferred aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and a slight amount of a foreign element as described above, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy are silicon,
Examples include iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of the foreign element in the alloy is 10 mass% or less. As the aluminum plate, pure aluminum is preferable, but completely pure aluminum is difficult to produce due to refining technology, and thus may contain a slightly different element. As described above, the composition of the aluminum plate is not specified, and an aluminum plate which is a publicly known and conventionally used material can be appropriately used. The thickness of the aluminum plate is preferably about 0.1 to 0.6 mm, and 0.15 to 0.4 mm.
mm is more preferable, and 0.2 to 0.3 mm is particularly preferable.

Before the surface roughening of the aluminum plate, if desired, a degreasing treatment for removing rolling oil on the surface is carried out, for example, with a surfactant, an organic solvent or an alkaline aqueous solution. The surface roughening treatment of the aluminum plate is carried out by various methods. For example, a method of mechanically roughening the surface, a method of electrochemically melting the surface and a method of selectively melting the surface chemically. It is performed by the method. As the mechanical method, known methods such as a ball polishing method, a brush polishing method, a blast polishing method and a buff polishing method can be used. As an electrochemical graining method, there is a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution.

The aluminum plate thus roughened is
Alkaline etching and neutralization as necessary
If desired, the surface water retention and abrasion resistance can be increased if desired.
Therefore, an anodic oxidation treatment is performed. Anodic acid by anodic oxidation
The amount of chemical film is 1.0 g / m ²The above is preferable. Anodic acid
The amount of chemical film is 1.0 g / m²Durability if less than
Is insufficient or when used as a lithographic printing plate
Is more likely to be scratched on the non-image area.
So-called "scratch and dirt" that ink adheres to the surface easily occurs
Sometimes. After being subjected to the anodizing treatment, the
The surface of minium is optionally hydrophilized.
It Further, such an aluminum support is anodized.
After processing, treatment with organic acid or its salt or image formation
A subbing layer for layer coating can be applied and used.

An intermediate layer may be provided to enhance the adhesion between the support and the image forming layer. In order to improve the adhesion, the intermediate layer is generally made of a diazo resin, a phosphoric acid compound adsorbed on aluminum, or the like. The thickness of the intermediate layer is arbitrary, and it must be a thickness capable of performing a uniform bond forming reaction with the upper image forming layer when exposed. Usually, a coating rate of about 1 to 100 mg / m ² as a dry solid is good, and 5 to 40 mg / m ² is particularly good. The proportion of the diazo resin used in the intermediate layer is 30 to 100% by mass, preferably 60 to 100% by mass.

After the surface of the support is subjected to the above treatment or undercoating, a back coat is provided on the back surface of the support, if necessary. As such a back coat, a coating layer made of a metal oxide obtained by hydrolyzing and polycondensing an organic polymer compound described in JP-A-5-45885 and an organic or inorganic metal compound described in JP-A-6-35174 is used. It is preferably used.

A preferable characteristic of the support for a lithographic printing plate is a center line average roughness of 0.10 to 1.2 μm. If it is less than 0.10 μm, the adhesion to the image forming layer is lowered, and the printing durability is remarkably reduced. If it is larger than 1.2 μm, the stain resistance during printing will deteriorate. Further, the color density of the support is 0.15 as the reflection density value.
If it is 0.65 and is whiter than 0.15, halation during image exposure is too strong to hinder image formation, and if it is blacker than 0.65, the image is difficult to see in the plate inspection work after development, The plate inspection property is remarkably poor.

On the support obtained by carrying out the predetermined treatment as described above, other optional layers such as the above-mentioned image forming layer, surface protective layer and back coat layer are formed. Thus, a negative image-forming material to which the method of the present invention can be applied can be obtained. In the method of the present invention, image recording is performed on the image forming material by the infrared laser described above. Also, thermal recording with an ultraviolet lamp or a thermal head is possible.

[Developing Solution and Replenishing Solution] As the developing solution and the replenishing solution, an alkaline aqueous solution having a pH range of 9 to 14 is preferably used. Examples of the alkaline compound used for preparing the alkaline aqueous solution include alkali metal hydroxides, alkaline earth metal hydroxides, silicates, alkali metal carbonates and hydrogen carbonates, alkaline earth metal carbonates and hydrogen carbonates. Examples thereof include salts, ammonium carbonates and hydrogen carbonates, and organic bases such as amines. It is also useful to incorporate various surfactants (nonionic, cationic, anionic).

This image-forming material is exposed with an infrared laser and then developed with the weak alkaline aqueous solution peculiar to the present invention described in detail above. The image-forming material developed using the developer and replenisher described above is optionally post-treated with washing water, a rinse solution containing a surfactant, a desensitizing solution containing gum arabic and a starch derivative. Later used as a lithographic printing plate.

In recent years, automatic developing machines for printing plate materials have been widely used in the plate making / printing industry in order to rationalize and standardize the plate making work. This automatic developing machine is generally composed of a developing section and a post-processing section, and is composed of a device for conveying a printing plate material, each processing liquid tank, and a spray device. Each of the processing liquids pumped up is sprayed from a spray nozzle for development processing. Further, recently, a method has also been known in which a printing plate material is dipped and conveyed by a submerged guide roll or the like in a treatment liquid tank filled with the treatment liquid for treatment. In such automatic processing,
It is possible to carry out the processing while supplementing the replenishing solution to each processing solution according to the processing amount, operating time and the like. Also, the electric conductivity can be detected by a sensor and automatically replenished. Further, a so-called disposable processing method of processing with a substantially unused processing liquid can be applied. According to the method of the present invention, there is no concern about deterioration of developability due to carbon dioxide gas over time and deterioration of printing durability due to a developing solution. Therefore, the method of the present invention is suitable for any of these automatic developing machines. Can be applied to.

The lithographic printing plate obtained as described above can be subjected to a printing step after applying a desensitizing gum if desired, but when a lithographic printing plate having higher printing durability is desired, Is subjected to a burning process. When burning a lithographic printing plate, before printing
No. 2518, No. 55-28062, JP-A-62-3
It is preferable to treat with a surface-adjusting solution as described in JP-A-1859 and JP-A-61-159655.

As a method for this, a sponge or absorbent cotton soaked with the surface-adjusting solution may be applied onto the planographic printing plate, or
A method in which the printing plate is dipped in a vat filled with a surface-adjusting solution to be applied, or an application by an automatic coater is applied. Further, making the coating amount uniform with a squeegee or a squeegee roller after coating gives more preferable results. The amount of the surface conditioning solution applied is generally 0.03 to 0.8 g / m ^2.
(Dry weight) is suitable.

The lithographic printing plate coated with the surface-adjusting solution is dried if necessary and then burned with a burning processor (for example,
It is heated to a high temperature with a burning processor: BP-1300) sold by Fuji Photo Film Co., Ltd. The heating temperature and the heating time in this case depend on the kinds of components forming the image, but are within the range of 180 to 300 ° C.
The range of up to 20 minutes is preferred.

The lithographic printing plate which has been subjected to the burning treatment can be subjected to conventional treatments such as washing with water and gumming, if necessary, but a surface-adjusting solution containing a water-soluble polymer compound or the like. When is used, so-called desensitizing treatment such as gumming can be omitted. The planographic printing plate obtained by the plate-making method of the present invention is set on an offset printing machine or the like and used for printing a large number of sheets.

[Examples] The present invention is described in detail below by referring to Examples, but the present invention is not limited thereto. [Preparation of support] 99.5% or more of aluminum and F
e 0.30%, Si 0.10%, Ti 0.02%, C
A molten JIS A1050 alloy containing 0.013% of u was subjected to a cleaning treatment and cast. For the cleaning treatment, degassing treatment was performed to remove unnecessary gas such as hydrogen in the molten metal, and ceramic tube filter treatment was performed. The casting method was a DC casting method. The solidified ingot having a plate thickness of 500 mm was chamfered by 10 mm from the surface, and homogenized at 550 ° C. for 10 hours so as not to coarsen the intermetallic compound. Then, after hot rolling at 400 ° C., intermediate annealing at 500 ° C. for 60 seconds in a continuous annealing furnace, cold rolling was performed to obtain an aluminum rolled plate having a plate pressure of 0.30 mm. The center line average surface roughness Ra after cold rolling was controlled to 0.2 μm by controlling the roughness of the rolling roll. Then, a tension leveler was applied to improve the flatness.

Next, a surface treatment was carried out to obtain a lithographic printing plate support. First, in order to remove the rolling oil on the surface of the aluminum plate, a 10% aqueous solution of sodium aluminate was added at 50 ° C for 30 minutes.
Degreasing for 30 seconds, 30% sulfuric acid aqueous solution at 50 ℃ 30
Neutralization was performed for 2 seconds, and smut removal treatment was performed.

Then, in order to improve the adhesion between the support and the image-forming layer and to impart water retention to the non-image area, a so-called graining treatment was carried out to roughen the surface of the support. 1
% Aqueous solution containing 5% nitric acid and 0.5% aluminum nitrate
While keeping the temperature at 5 ° C., while flowing the aluminum web in the aqueous solution, an anode side electricity quantity of 240 C / d with an alternating waveform of a current density of 20 A / dm ² and a duty ratio of 1: 1 by an indirect power supply cell.
Electrolytic graining was performed by giving m ² . Then 10
% Sodium aluminate aqueous solution at 50 ° C. for 30 seconds, and 30 %% sulfuric acid aqueous solution at 50 ° C. for 30 seconds for neutralization to remove smut.

Further, in order to improve abrasion resistance, chemical resistance and water retention, an oxide film was formed on the support by anodic oxidation. Anodized film of 2.5 g / m ² is obtained by using a 20% aqueous solution of sulfuric acid as an electrolyte at 35 ° C. and carrying out an electrolytic treatment with a direct current of 14 A / dm ² by an indirect power supply cell while carrying the aluminum web through the electrolyte. It was created.

Thereafter, in order to secure hydrophilicity as a non-image area of the printing plate, a silicate treatment was performed. The treatment was carried out by keeping a 1.5% aqueous solution of sodium silicate No. 3 at 70 ° C. so that the contact time of the aluminum web was 15 seconds, and further washing with water. S
The amount of i deposited was 10 mg / m ² . Ra (center line surface roughness) of the support prepared as described above was 0.25 μm.

[Undercoat] Next, the following undercoat solution was applied to the aluminum support with a wire bar and dried at 90 ° C. for 30 seconds using a warm air dryer. The coated amount after drying was 10 mg / m ² .

[0123] <Undercoat liquid> ・ Ethyl methacrylate and 2-acrylamido-2-methyl-1-propanus 0.1 g of a copolymer of sodium ruphonate with a molar ratio of 75:15 ・ 2-Aminoethylphosphonic acid 0.1 g ・ Methanol 50g ・ Ion-exchanged water 50g

[Image Forming Layer] Next, the following image forming layer coating liquid [P] was prepared and applied to the above-mentioned undercoated aluminum plate using a wire bar, and then dried with a warm air dryer.
An image forming layer was formed by drying at 15 ° C. for 45 seconds to obtain a negative lithographic printing plate precursor [P-1], which was referred to as Example 1. The coating amount after drying was in the range of 1.2 to 1.3 g / m ² .

[0125] <Image forming layer coating liquid [P]> ・ Infrared absorber [IR-6] 0.08 g Onium salt [OI-6] 0.30 g ・ Dipentaerythritol hexaacrylate 1.00 g -Copolymer of allyl methacrylate and methacrylic acid in a molar ratio of 80:20 (weight Average molecular weight 120,000) 1.00g ・ Victoria Pure Blue Naphthalene Sulfonate 0.04g ・ Fluorosurfactant 0.01g (Megafuck F-176, manufactured by Dainippon Ink and Chemicals, Inc.) ・ Methyl ethyl ketone 9.0 g ・ Methanol 10.0g ・ 1-Methoxy-2-propanol 8.0 g ・ Unsaturated group-containing UV polymerization initiator 0.3g

[0126]

[Chemical 25]

[Exposure] The obtained negative type lithographic printing plate precursor [P-1] was transferred to Creo's Trendsetter 3244VF equipped with a water-cooled 40 W infrared semiconductor laser.
At S, output is 9 W, external drum rotation speed is 210 rpm, plate surface energy is 100 mJ / cm ² , resolution is 2400 dp.
It was exposed under the conditions of i.

[Development processing] After exposure, development processing was carried out using an automatic processor Stablon 900N manufactured by Fuji Photo Film Co., Ltd. As the developing solution, a developing solution [1] (pH 9.9 at 25 ° C.) having the following formulation was used for both the charging solution and the replenishing solution. The temperature of the developing bath was 30 ° C. In addition, the finisher
A 1: 1 water dilution of FN-6 manufactured by Fuji Photo Film Co., Ltd. was used. In addition, the pH of each of the developing solutions shown below is 25
The results measured at ° C are shown.

[0129] <Developer [1]> ・ Sodium carbonate monohydrate 10 g ・ Potassium hydrogen carbonate 10g ・ Sodium isopropyl naphthalene sulfonate 15g ・ Sodium dibutylnaphthalene sulfonate 15g ・ Ethylene glycol mononaphthyl ether monosulfate sodium salt                                                                10 g ・ Sodium sulfite 1g ・ Ethylenediaminetetraacetic acid tetrasodium 0.1g ・ Ion-exchanged water 938.9g

The entire surface was exposed under the conditions shown in Table 1 and the printing durability was evaluated under the conditions described below. [Printing durability] Next, the planographic printing plate [P-1] was printed using a printing machine Lithrone manufactured by Komori Corporation.
At this time, after the start of printing, it was visually evaluated how many prints were sufficiently coated with ink (Table 1).
For solid printing durability, the number of sheets printed on the entire image area was evaluated. The highlight printing durability was evaluated by the number of sheets at which the dot at the 3% halftone dot area became about half.

As is clear from Table 1, the printing durability was considerably low when the image forming layer containing no UV polymerization initiator having a polymerizable unsaturated group was used and the entire surface was not exposed ( Comparative example 2). Further, by using an image forming layer containing no ultraviolet polymerization initiator having a polymerizable unsaturated group,
When the entire surface was exposed, the printing durability was slightly improved, but both solid printing durability and highlight printing durability were inferior to those of the present invention (Comparative Example 1). On the other hand, when the infrared-sensitive lithographic printing plate containing the UV-polymerization initiator having a polymerizable unsaturated group in the image forming layer is imagewise exposed and developed and then exposed to UV light, the solid printing durability is And highlight printing durability were dramatically improved (Examples 1 to 1)
4).

[0132]

[Table 1]

[0133]

[Chemical formula 26]

EFFECT OF THE INVENTION (A) Infrared absorber, (B) on support
Radical generator, (C) radically polymerizable compound, (D)
A photopolymerizable infrared-sensitive lithographic printing plate precursor having an image forming layer containing a binder polymer and (E) a UV-polymerization initiator having a polymerizable unsaturated group is subjected to infrared image exposure, developed, and then exposed to UV light for the entire surface. The lithographic printing plate produced by the lithographic printing plate making method characterized by exposing is
Shows outstanding printing durability.

Claims (4)

[Claims] 1. An infrared absorbent (A) on a support,
(B) radical generator, (C) radically polymerizable compound,
After the photopolymerization type infrared-sensitive lithographic printing plate precursor having an image forming layer containing (D) a binder polymer and (E) an ultraviolet polymerization initiator having a polymerizable unsaturated group, is subjected to infrared image exposure and development, A method of making a planographic printing plate, which comprises exposing the entire surface to ultraviolet rays. 2. The plate making method according to claim 1, wherein the exposure amount at the time of whole surface exposure is at least equal to the image exposure amount. 3. The plate surface temperature is 30 to 150 when the entire surface is exposed.
The plate-making method according to claim 1 or 2, wherein the plate-making method is performed by heating to ℃. 4. An infrared absorbing agent (A) on a support,
(B) radical generator, (C) radically polymerizable compound,
A lithographic printing plate precursor having an image forming layer containing (D) a binder polymer and (E) an ultraviolet polymerization initiator having a polymerizable unsaturated group.