JP2003015281A - Photosensitive planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive planographic printing plate having high sensitivity, a superior image forming property and a wide development latitude, not contaminating the optical system of an exposure device and capable of forming an image with an IR laser for direct plate making. SOLUTION: The photosensitive planographic printing plate is obtained by disposing at least two recording layers having solubility in an alkaline aqueous solution increased under infrared light on a hydrophilic support and at least one of the recording layers contains an IR absorbent having two or more chromophores capable of absorbing IR in the same molecule and obtained by bonding the chromophores through a covalent bond.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive lithographic printing plate, and more particularly to a positive type photosensitive lithographic printing plate for infrared laser for so-called direct plate making which can be made directly from a digital signal of a computer or the like. Relates to a photosensitive lithographic printing plate having high sensitivity and a wide development allowable range.

[0002]

2. Description of the Related Art In recent years, with the development of solid-state lasers and semiconductor lasers having a light emitting region from near infrared to infrared, as a system for directly making a plate from computer digital data,
The thing using these infrared lasers attracts attention. A positive type lithographic printing plate material for infrared laser for direct plate making is disclosed in JP-A-7-285275. The present invention is an image recording material in which a substance that absorbs light and generates heat and a positive photosensitive compound such as quinonediazide compounds are added to an alkali aqueous solution soluble resin, and a positive photosensitive compound is used in the image area. However, it acts as a dissolution inhibitor that substantially reduces the solubility of the alkali aqueous solution soluble resin, and in the non-image area it is decomposed by heat so that it does not develop the dissolution inhibiting ability, and it can be removed by development, and the image is Form.

As a result of investigations by the present inventors, it was found that a positive image can be obtained without adding quinonediazide compounds to an image recording material. However, in an image recording material from which quinonediazide compounds are simply removed, There is a drawback that the stability of sensitivity with respect to the concentration of the developing solution, that is, the latitude of development is deteriorated.

On the other hand, it is known that onium salts and alkali-insoluble hydrogen-bondable compounds have an alkali dissolution inhibiting effect on alkali-soluble polymers. WO 97/39894 describes that a composition using a cationic infrared absorbing dye as a dissolution inhibitor of an alkaline water-soluble polymer exhibits a positive action as an infrared laser compatible image forming material. This positive action is a function in which the infrared absorbing dye absorbs the laser light and the generated heat eliminates the dissolution inhibiting effect of the polymer film in the irradiated portion to form an image.

The image-forming property is sufficient on the laser-irradiated surface of the light-sensitive material, but due to thermal diffusion, a sufficient effect cannot be obtained down to the deep portion of the light-sensitive material. -There was a problem that it was difficult to turn off and a good image could not be obtained (low sensitivity, narrow development latitude). The development latitude referred to here means an allowable range in which good image formation can be performed when the alkali concentration of the alkali developer is changed. Further, when the exposure amount is increased in order to obtain a sufficient development latitude, there is a problem that the infrared absorber and other components in the photosensitive layer are ablated to contaminate the optical system of the exposure machine.

[0006]

SUMMARY OF THE INVENTION Accordingly, the object of the present invention is to provide a high sensitivity, excellent image forming property, and a wide development allowable range.
Another object of the present invention is to provide a photosensitive lithographic printing plate capable of forming an image with an infrared laser for direct plate making that does not contaminate the optical system of the exposure device.

[0007]

As a result of earnest studies, the inventors of the present invention have improved both sensitivity and image formability by using a recording layer having a structure of two or more layers and using a specific infrared absorber. However, they have found that the ablation of the infrared absorber can be suppressed, and have completed the present invention.

That is, the present invention is as follows. (1) A photosensitive lithographic printing plate comprising at least two recording layers, the solubility of which in an alkaline aqueous solution is increased by infrared light, provided on a hydrophilic support, and at least one of the recording layers is the same. A photosensitive lithographic printing plate comprising an infrared absorber having two or more chromophores capable of absorbing infrared rays in the molecule and having the chromophores bonded by a covalent bond.

(2) The photosensitive lithographic printing plate as described in (1) above, wherein the infrared absorbent is represented by the following general formula (I).

(D) _n -A General formula (I)

(In the formula, A represents a divalent or higher valent organic group, and n
Represents an integer of 2 or more. D represents a chromophore having absorption in the infrared region, and two or more chromophores may be the same or different. When the chromophore moiety has a charge, it may be accompanied by an ion having a charge opposite to that of the chromophore for neutralizing the charge. )

Although the action of the present invention is not clear, by using an infrared absorbent having two or more chromophores in the same molecule, the two chromophores are present in the vicinity and the distribution of the dye is locally distributed. Since it is localized, some parts locally reach high temperatures. Furthermore, due to the linking of this chromophore, the dye forms an association state, which accelerates the relaxation process from the excited state.
It is considered that the amount of heat generation is increased, and these effects can achieve high sensitivity and improvement in image formability. Also,
Since it has two chromophores, its molecular weight is larger than that of an infrared absorber having only one chromophore, and it is considered that scattering due to ablation due to heat generation during exposure can be suppressed. Furthermore, the chromophore bound by a covalent bond does not dissociate even when dissolved in the solvent of the recording layer coating solution, and the salt exchange with other salt compounds in the coating solution may increase the distance between the chromophores. Since it does not exist, there is an advantage that the effect does not decrease even when the recording layer of the photosensitive lithographic printing plate is formed.

Further, the recording layer has a structure of two or more layers, more specifically, a structure in which the upper layer side is relatively insoluble in alkali and the lower layer side is insoluble in alkali relatively easily. It is considered that the sensitivity was excellent and the image forming property was excellent.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. [(A) Infrared absorber] First, the infrared absorber contained in the recording layer of the photosensitive lithographic printing plate of the invention will be described. The infrared absorbent according to the present invention is characterized by having two or more chromophores in the same molecule, and the chromophores being bound by a covalent bond. The function of the infrared absorbent according to the present invention is to generate heat by infrared exposure and record with the heat, like the infrared absorbent contained in a general recording material capable of forming an image by exposure in the infrared region. . For this reason, it is necessary to contain the infrared absorbing agent that efficiently converts the light of the infrared laser into heat. The chromophore of the infrared absorber used here has absorption in the infrared region,
Specifically, it has absorption at a wavelength of 720 nm to 1200 nm, and preferably has an absorption maximum at a wavelength of 720 nm to 1200 nm.

The infrared absorbent according to the present invention is not particularly limited as long as it is as shown above, but is preferably represented by the following general formula (I).

(D) _n -A General formula (I)

(In the formula, A represents a divalent or higher valent organic group, and n
Represents an integer of 2 or more. D represents a chromophore having absorption in the infrared region, and two or more chromophores may be the same or different. When the chromophore moiety has a charge, it may be accompanied by an ion having a charge opposite to that of the chromophore for neutralizing the charge. ) The above general formula (I)
The chromophores represented by Medium D may be the same or different from each other, but those having the same structure can be easily produced from the viewpoint of the synthetic method.

The infrared absorber having two or more chromophores in the same molecule as described above will be described in detail below with reference to specific examples. The following exemplified compounds (IR-1) to (IR-5
In 1), in the above general formula (I) that functions as a basic skeleton and a linking group, an organic group corresponding to A (denoted as A ^{1 to} A ¹² ) and a substituent (R ^{1 to} R) present in the chromophore. ⁴ ) and these chromophores have a charge, so the counterion X ⁻ is specifically indicated. The present invention is not limited to this.

[0019]

[Chemical 1]

[0020]

[Chemical 2]

[0021]

[Chemical 3]

[0022]

[Chemical 4]

[0023]

[Chemical 5]

[0024]

[Chemical 6]

[0025]

[Chemical 7]

[0026]

[Chemical 8]

[0027]

[Chemical 9]

[0028]

[Chemical 10]

[0029]

[Chemical 11]

[0030]

[Chemical 12]

[0031]

[Chemical 13]

Of these, the exemplified compounds (IR-1) to (IR-49) in which the two chromophores are the same are easy to synthesize, but the exemplified compounds (IR-50) to (IR-51).
As shown in, the chromophores may be different from each other.

Next, a method for producing the above infrared absorbent will be described. The infrared absorber represented by the general formula (I) can be produced by a known organic synthesis technique. Specifically, it can be synthesized by the synthesis method described in JP-A-8-95197, registered patent No. 2758136, and the like. When the organic group (A) having a valence of 2 or more has a valence of 3 or more, it is not necessary that all the linking sites are bonded to the dye moiety.
It can be used as a mixture of compounds in which two or more dye moieties are linked.

The infrared absorbent may be added to the recording layer together with other components, or may be added to a layer other than the recording layer provided in the preparation of the photosensitive lithographic printing plate. These infrared absorbers may be added alone or in combination of two or more. In the present invention, these infrared absorbers are contained in an amount of 0.01 to 50% by weight, preferably 0.1 to 20% by weight, more preferably 0.5 to 15% by weight, based on the total solid content of the recording layer. It can be added in proportion. If the addition amount is less than 0.01% by weight, the image forming property is deteriorated, and if the addition amount exceeds 50% by weight, the non-image area may be stained.

To the photosensitive lithographic printing plate of the present invention, in addition to the infrared absorbing agent, other infrared absorbing pigments or dyes may be added for the purpose of improving the image forming property. As pigments, commercially available pigments and color index (CI) handbook, "latest pigment handbook" (edited by Japan Pigment Technology Association, published in 1977), "latest pigment application technology"
(CMC Publishing, 1986), "Printing Ink Technology" C
The pigments described in MC Publishing, 1984) 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 pigments, nitroso pigments, nitro pigments, natural pigments, fluorescent pigments, inorganic pigments, carbon black and the like can be used.

These pigments may be used without being surface-treated, or may be used after being surface-treated. Surface treatment methods include resin or wax surface coating, surfactant attachment, and reactive substances (eg, silane coupling agents, epoxy compounds, polyisocyanates, etc.)
It is possible to consider a method of binding the pigment to the surface of the pigment. The above surface treatment method is "property and application of metal soap" (Koushobo),
"Printing Ink Technology" (CMC Publishing, 1984) and "Latest Pigment Application Technology" (CMC Publishing, 1986)
It is described in.

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 recording layer coating liquid, and when it exceeds 10 μm, it is not preferable from the viewpoint of uniformity of the recording layer. As a method for dispersing the pigment, a known dispersion technique used in ink production, toner production or the like can be used. As the disperser, ultrasonic disperser, sand mill, attritor, pearl mill, super mill,
A ball mill, an impeller, a despather, a KD mill, a colloid mill, a dynatron, a three roll mill, a pressure kneader and the like can be mentioned. For details, see "Latest Pigment Application Technology."
(CMC Publishing, published in 1986).

As the dye, commercially available dyes and known dyes described in the literature (for example, "Dye Handbook" edited by the Society of Organic Synthetic Chemistry, published in 1970) can be used. Specific examples thereof include azo dyes, metal complex salt azo dyes, pyrazolone azo dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, diimonium dyes, and aminium dyes. In the present invention, among these pigments or dyes, those that absorb infrared light or near infrared light are particularly preferable because they are suitable for use in a laser that emits infrared light or near infrared light.

Carbon black is preferably used as such a pigment that absorbs infrared light or near infrared light. Examples of dyes that absorb infrared light or near infrared light include those disclosed in JP-A-58-125246 and JP-A-5-125246.
Cyanine dyes described in JP-A No. 9-84356, JP-A No. 59-202829, JP-A No. 60-78787, JP-A No. 58-173696, and JP-A No. 58-181.
690, methine dyes described in JP-A-58-194595, JP-A-58-112793, JP-A-58-224793, JP-A-59-48187, and JP-A-59-73996. JP-A-60-52940,
Naphthoquinone dyes described in JP-A-60-63744, squarylium dyes described in JP-A-58-112792, cyanine dyes described in British Patent 434,875, and US Pat. No. 5,380,635. And the dihydroperimidine squarylium dyes and the like described in No.

Further, as a dye, US Pat. No. 5,156,56
The near-infrared absorption sensitizer described in US Pat. No. 938 is also preferably used, and the substituted arylbenzo (thio) pyrylium salt described in US Pat. No. 3,881,924, JP-A-57-1.
No. 42645 (US Pat. No. 4,327,169), a trimethine thiapyrylium salt, JP-A-58-1810.
No. 51, No. 58-220143, No. 59-41363.
No. 59-84248, No. 59-84249, No. 59-146063, No. 59-146061, and the pyrylium compounds described in JP-A-59-2161.
Cyanine dye described in US Pat. No. 4,283,4
No. 75, pentamethine thiopyrylium salt and the like, the pyrilium compounds disclosed in Japanese Examined Patent Publication Nos. 5-13514 and 5-19702, and commercially available products include Epol.
light III-178, Epolight III-13
0, Epolight III-125, Epolight
IV-62A (manufactured by Eporin) and the like are particularly preferably used.

Another particularly preferable example of the dye is the near-infrared absorbing dyes described as formulas (I) and (II) in US Pat. No. 4,756,993. Since these pigments or dyes are used in combination with the above-mentioned specific infrared absorber, the addition amount when added is 0.01 to 20 relative to the total solid content of the recording layer.
It is preferably about 10% by weight, and particularly preferably in the case of a dye, 0.1.
5 to 10% by weight, particularly preferably 0.1 to 5 in the case of pigment
Add at a weight percentage. If the amount of the pigment or dye added is less than 0.01% by weight, the effect of the addition will not be seen, and if it exceeds 20% by weight, the effect of increasing the sensitivity due to the specific infrared absorber may be affected. It is not preferable because it is present.

The photosensitive lithographic printing plate of the present invention comprises at least two recording layers on a hydrophilic support, the solubility of which in an alkaline aqueous solution is increased by infrared light.
There is no particular limitation as long as at least one of the recording layers contains the above specific infrared absorber.

First, in the photosensitive lithographic printing plate of the present invention having at least two recording layers, of the two positive recording layers, the one provided on the side closer to the surface (exposed surface) is top-recorded. The layer provided on the side close to the support is called the lower recording layer. In this case, it is preferable that the lower layer of the positive type recording layer has higher solubility in alkali than the upper layer thereof.

(Upper Recording Layer) The coating amount of the upper recording layer is
It is preferably in the range of 0.05 to 0.45 g / m ² . When the coating amount of the upper recording layer is less than 0.05 g / m ² , heat generated by imagewise exposure diffuses to the lower recording layer,
There is a tendency that the heat is absorbed to lower the sensitivity, and the film strength in the image forming area (unexposed portion) is insufficient. On the other hand, if the coating amount of the upper recording layer exceeds 0.45 g / m ² , it is necessary to raise the temperature of the entire upper recording layer at the time of image formation to form an image, and the sensitivity is lowered. It is likely to be affected by scratches formed on the surface, and the chemical resistance at the time of printing tends to decrease, either of which is not preferable. The upper recording layer essentially contains a water-insoluble and alkali-soluble resin,
It preferably contains the above infrared absorber.

In the present invention, a water-insoluble and alkali-water-soluble polymer compound used in the recording layer (hereinafter referred to as appropriate)
The term "alkali-soluble polymer" includes a homopolymer containing an acidic group in the main chain and / or side chain of the polymer, a copolymer thereof, or a mixture thereof. Therefore, the polymer layer according to the present invention has a property of dissolving when contacted with an alkaline developer. Among these, those having an acidic group described in (1) to (6) below in the main chain and / or side chain of the polymer are preferable from the viewpoint of solubility in an alkaline developer.

(1) Phenolic hydroxyl group (-Ar-O
H) (2) sulfonamide group _{(-SO 2 NH-R) (} 3) substituted sulfonamide-based acid group (hereinafter, referred to as "active imide group") _{[-. SO 2 NHCOR, -SO 2} NHSO
₂ R, -CONHSO ₂ R] (4) carboxylic acid group (-CO ₂ H) (5) sulfonic acid group (-SO ₃ H) (6) phosphoric acid group (-OPO ₃ H ₂₎

In the above (1) to (6), Ar represents a divalent aryl linking group which may have a substituent, and R represents a hydrocarbon group which may have a substituent. . Above (1)
Among the alkaline water-soluble polymers having an acidic group selected from (6) to (6), an alkaline water-soluble polymer having (1) a phenol group, (2) a sulfonamide group and (3) an active imide group is preferable, and particularly, Alkaline water-soluble polymers having (1) a phenol group or (2) a sulfonamide group are most preferable from the viewpoint of ensuring sufficient solubility in an alkaline developer and film strength.

Next, typical examples of the polymerization components of these alkaline water-soluble polymer compounds will be described. (1) Examples of the polymerizable monomer having a phenolic hydroxyl group include a polymerizable monomer composed of a phenolic hydroxyl group and a low molecular weight compound having at least one polymerizable unsaturated bond, and examples thereof include a phenolic hydroxyl group. Examples thereof include acrylamide, methacrylamide, acrylic acid ester, methacrylic acid ester, and hydroxystyrene.

Specifically, for example, N- (2-hydroxyphenyl) acrylamide, N- (3-hydroxyphenyl) acrylamide, N- (4-hydroxyphenyl) acrylamide, N- (2-hydroxyphenyl).
Methacrylamide, N- (3-hydroxyphenyl) methacrylamide, N- (4-hydroxyphenyl) methacrylamide, o-hydroxyphenyl acrylate,
m-hydroxyphenyl acrylate, p-hydroxyphenyl acrylate, o-hydroxyphenyl methacrylate, m-hydroxyphenyl methacrylate, p
-Hydroxyphenyl methacrylate, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, 2- (2-hydroxyphenyl) ethyl acrylate, 2- (3-hydroxyphenyl) ethyl acrylate, 2- (4-hydroxyphenyl) Examples thereof include ethyl acrylate, 2- (2-hydroxyphenyl) ethyl methacrylate, 2- (3-hydroxyphenyl) ethyl methacrylate and 2- (4-hydroxyphenyl) ethyl methacrylate. Two or more kinds of these monomers having a phenolic hydroxyl group may be used in combination.

(2) As the polymerizable monomer having a sulfonamide group, a sulfonamide group (-NH-SO) in which at least one hydrogen atom is bonded to a nitrogen atom in one molecule is used.
_2- ) and a low molecular weight compound each having one or more polymerizable unsaturated bonds, and examples thereof include a polymerizable monomer. For example, an acryloyl group, an allyl group, or a vinyloxy group, and a substituted or monosubstituted aminosulfonyl group. Alternatively, a low molecular weight compound having a substituted sulfonylimino group is preferable. Examples of such a compound include, for example, JP-A-8-1
Examples thereof include compounds represented by formulas (I) to (V) described in No. 23029.

(2) Specific examples of the polymerizable monomer having a sulfonamide group include m-aminosulfonylphenyl methacrylate, N- (p-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) acrylamide and the like. Can be preferably used.

(3) As the polymerizable monomer having an active imide group, those having an active imide group described in JP-A No. 11-84657 in the molecule are preferable, and one in one molecule,
Examples of the polymerizable monomer include an active imide group and a low molecular weight compound having at least one polymerizable unsaturated bond. (3) As the polymerizable monomer having an active imide group,
Specifically, N- (p-toluenesulfonyl) methacrylamide, N- (p-toluenesulfonyl) acrylamide and the like can be preferably used.

(4) Examples of the alkaline water-soluble polymer having a carboxylic acid group include, for example, a minimum constitutional unit derived from a compound having at least one carboxylic acid group and at least one polymerizable unsaturated group in the molecule. A polymer as a main constituent may be mentioned. (5) As the alkali-soluble polymer having a sulfonic acid group, for example, a minimum structural unit derived from a compound having at least one sulfonic acid group and at least one polymerizable unsaturated group in the molecule is a main structural unit. Polymers can be mentioned. (6) As the alkaline water-soluble polymer having a phosphate group, for example, a main structural component is a minimum structural unit derived from a compound having at least one phosphoric acid group and at least one polymerizable unsaturated group in the molecule. The following polymers may be mentioned.

The minimum constitutional unit having an acidic group selected from the above (1) to (6), which constitutes the alkaline water-soluble polymer used in the photosensitive lithographic printing plate of the present invention, is required to be only one kind. Alternatively, two or more kinds of minimum constituent units having the same acidic group or two or more kinds of minimum constituent units having different acidic groups can be used.
As the copolymerization method, a conventionally known graft copolymerization method, block copolymerization method, random copolymerization method or the like can be used.

The copolymer is copolymerized (1) to
A compound having an acidic group selected from (6) is preferably contained in the copolymer in an amount of 10 mol% or more, more preferably 20 mol% or more. 10 mol%
If it is less than 1, the developing latitude tends to be insufficiently improved.

In the present invention, when a compound is copolymerized to form a copolymer, the compound (1) to
Other compounds that do not contain the acidic group of (6) can also be used. Examples of (1) to (6) other compounds that do not contain an acidic group include the compounds listed in (m1) to (m12) below, but are not limited thereto.

(M1) Acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group such as 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate. (M2) methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate,
Alkyl acrylates such as hexyl acrylate, octyl acrylate, benzyl acrylate, 2-chloroethyl acrylate and glycidyl acrylate. (M3) Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methacrylic acid-2-
Alkyl methacrylates such as chloroethyl, glycidyl methacrylate, etc.

(M4) Acrylamide, methacrylamide, N-methylolacrylamide, N-ethylacrylamide, N-hexylmethacrylamide, N-cyclohexylacrylamide, N-hydroxyethylacrylamide, N-phenylacrylamide, N-nitrophenylacrylamide, N -Acrylamide or methacrylamide such as ethyl-N-phenylacrylamide.

(M5) Vinyl ethers such as ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether and phenyl vinyl ether. (M6) vinyl acetate, vinyl chloroacetate,
Vinyl esters such as vinyl butyrate and vinyl benzoate. (M7) Styrenes such as styrene, α-methylstyrene, methylstyrene and chloromethylstyrene. (M8) Vinyl ketones such as methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and phenyl vinyl ketone.

(M9) Olefins such as ethylene, propylene, isobutylene, butadiene and isoprene. (M10) N-vinylpyrrolidone, acrylonitrile,
Methacrylonitrile etc. (M11) Unsaturated imides such as maleimide, N-acryloylacrylamide, N-acetylmethacrylamide, N-propionylmethacrylamide, and N- (p-chlorobenzoyl) methacrylamide. (M12) An unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic anhydride or itaconic acid.

As the alkaline water-soluble polymer compound,
It is preferable to have a phenolic hydroxyl group from the viewpoint of excellent image formability upon exposure with an infrared laser or the like. For example, phenol formaldehyde resin, m-cresol formaldehyde resin, p-cresol formaldehyde resin, m- / p-mixed cresol formaldehyde. Resin, phenol / cresol (m-, p-, or m- /
Preference is given to novolak resins such as mixed formaldehyde resins and pyrogallolacetone resins.

As the alkaline water-soluble polymer compound having a phenolic hydroxyl group, further, as described in US Pat. No. 4,123,279,
Carbon number 3 ~, such as t-butylphenol formaldehyde resin and octylphenol formaldehyde resin
Examples thereof include a condensation polymer of phenol and formaldehyde having the alkyl group of 8 as a substituent. The weight average molecular weight of the alkaline water-soluble polymer compound is preferably 500 or more, more preferably 1,000 to 700,000. The number average molecular weight is 5
00 or more, preferably 750 to 650,00
It is more preferably 0. The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 10.

The alkaline water-soluble polymer compound may be used alone or in combination of two or more kinds, and the total content thereof is preferably 1 to 90% by weight in the total solid content of the upper recording layer, and 2 to 70% by weight. % By weight is more preferable, and 2 to 50% by weight is particularly preferable. When the content is less than 1% by weight, the durability tends to deteriorate, and when it exceeds 90% by weight, the sensitivity and the image forming property tend to decrease, which is not preferable.

(Lower Recording Layer) Next, of the at least two recording layers, the lower recording layer provided on the side closer to the support will be described. The lower recording layer essentially contains a water-insoluble and alkali-soluble resin and, if necessary, an infrared absorber. The water-insoluble and alkali-soluble resin contained in the lower recording layer may be the same as those described above in the upper recording layer. Above all, when the upper recording layer and the lower recording layer are provided adjacent to each other, the lower recording is performed at the time of application of the upper recording layer in order to suppress the deterioration of the effect due to the fact that the interfaces of the upper recording layer and the lower recording layer are compatible with each other and the interface is not clear. It is preferable that the alkali-soluble polymer used in the lower recording layer and the one used in the upper recording layer have different solubilities in the coating solvent so that the layer is not dissolved. The alkaline water-soluble polymer compounds may be used alone or in combination of two or more kinds,
The total content is also preferably 1 to 90% by weight in the total solid content of the lower recording layer, as in the upper recording layer, and 2 to
70 wt% is more preferable, and 2 to 50 wt% is particularly preferable.

The coating amount of the lower recording layer is not particularly limited and can be selected according to the application, desired sensitivity, recording characteristics, etc., but generally 0.5 to 5.0 g / m ² is preferable.
The upper and lower recording layers of the photosensitive lithographic printing plate having at least two recording layers are usually prepared by dissolving each of the above components in a solvent and coating the coating liquid for the lower recording layer on a suitable support. It can be manufactured by applying the coating liquid for the upper recording layer. It is also possible to apply two recording layers in a multi-layered manner using a predetermined device.

[Other Components] In forming the positive recording layer, various additives may be added, if necessary, in addition to the components described above, as long as the effects of the present invention are not impaired. You can For example, onium salt, o-
The use of a substance such as a quinonediazide compound, an aromatic sulfone compound, an aromatic sulfonic acid ester compound, which is thermally decomposable and which substantially reduces the solubility of the alkaline water-soluble polymer compound when not decomposed, causes It is preferable from the viewpoint of improving the dissolution inhibiting property of the above in the developing solution. Examples of onium salts include diazonium salts, ammonium salts, phosphonium salts, iodonium salts, sulfonium salts, selenonium salts, arsonium salts and the like.

Suitable onium salts used in the present invention include, for example, SI Schlesinger,
Photogr. Sci. Eng., 18, 387 (1974), TS Bal et
al, Polymer, 21, 423 (1980), JP-A-5-158230.
Diazonium salt described in U.S. Pat. No. 4,069,055
No. 4,069,056, ammonium salts described in JP-A-3-140140, DC Necker et al, Macromolecul
es, 17, 2468 (1984), CS Wen et al, Teh, Proc. Co
nf.Rad. Curing ASIA, p478 Tokyo, Oct (1988), U.S. Pat.
(6), 1307 (1977), Chem. & Eng. News, Nov. 28, p31.
(1988), European Patent 104,143, U.S. Patent 339,049.
No. 410,201, JP-A No. 2-150848, and JP-A No. 2-2965.
Iodonium salt described in No. 14, JVCrivello et al, P
olymer J. 17, 73 (1985), JV Crivello et al. J.
Org. Chem., 43, 3055 (1978), WR Watt et al, J. P.
olymer Sci., Polymer Chem. Ed., 22, 1789 (1984),
JV Crivello et al, Polymer Bull., 14, 279 (198
5), JV Crivello et al, Macromorecules, 14 (5)
, 1141 (1981), JV Crivello et al, J. Polymer Sc
i., Polymer Chem. Ed., 17, 2877 (1979), European Patent Nos. 370,693, 233,567, 297,443 and 297,44.
2, U.S. Pat.Nos. 4,933,377, 3,902,114, 41
0,201, 339,049, 4,760,013, 4,734,44
4, 2,833,827, German Patent 2,904,626, 3,
604,580 and 3,604,581 described sulfonium salts,
JV Crivello et al, Macromorecules, 10 (6), 1307
(1977), JV Crivello et al, J. Polymer Sci., Pol.
ymer Chem. Ed., 17, 1047 (1979), selenonium salt, CS Wen et al, Teh, Proc. Conf. Rad. Curing
Examples include arsonium salts described in ASIA, p478 Tokyo, Oct (1988). Among the onium salts, the diazonium salt is particularly preferable. Further, particularly preferable diazonium salts include those described in JP-A-5-158230.

As the counter ion of the onium salt, tetrafluoroboric acid, hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid, 5-nitro-o-toluenesulfonic acid, 5
-Sulfosalicylic acid, 2,5-dimethylbenzenesulfonic acid, 2,4,6-trimethylbenzenesulfonic acid, 2
-Nitrobenzenesulfonic acid, 3-chlorobenzenesulfonic acid, 3-bromobenzenesulfonic acid, 2-fluorocaprylnaphthalenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5- Examples thereof include benzoyl-benzenesulfonic acid and paratoluenesulfonic acid. Among these, alkylaromatic sulfonic acids such as hexafluorophosphoric acid, triisopropylnaphthalenesulfonic acid and 2,5-dimethylbenzenesulfonic acid are particularly preferable.

Suitable quinonediazides include o-quinonediazide compounds. The o-quinonediazide compound used in the present invention is a compound having at least one o-quinonediazide group, which increases alkali solubility by thermal decomposition, and compounds having various structures can be used. That is, o-quinonediazide assists the solubility of the light-sensitive material system by both the effect of losing the ability to suppress the dissolution of the binder by thermal decomposition and the effect of changing o-quinonediazide itself into an alkali-soluble substance. Examples of the o-quinonediazide compound used in the present invention include those described in J. The compounds described on pages 339 to 352 of "Light-Sensitive Systems" (John Wiley & Sons. Inc.) by Coser can be used, but in particular, they have been reacted with various aromatic polyhydroxy compounds or aromatic amino compounds. -Sulfonic acid esters or sulfonic acid amides of quinonediazide are preferred. Further, benzoquinone (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,3) as described in JP-B-43-28403.
2) -Diazido-5-sulfonic acid chloride ester with pyrogallol-acetone resin, US Pat. No. 3,046,12
And esters of benzoquinone- (1,2) -diazide sulfonic acid chloride or naphthoquinone- (1,2) -diazide-5-sulfonic acid chloride with phenol-formaldehyde resin described in No. 0 and No. 3,188,210. It is preferably used.

Further, an ester of naphthoquinone- (1,2) -diazide-4-sulfonic acid chloride and a phenol formaldehyde resin or a cresol-formaldehyde resin, naphthoquinone- (1,2) -diazide-
Esters of 4-sulfonic acid chloride and pyrogallol-acetone resin are likewise preferably used. Other useful o-quinonediazide compounds are reported and known in numerous patents. For example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, and JP-A-48-9657.
5, JP49-38701, JP48-13354, JP4
1-11222, Japanese Patent Publication 45-9610, Japanese Patent Publication 49-17481,
U.S. Pat.Nos. 2,797,213, 3,454,400, 3,544,
No. 323, No. 3,573,917, No. 3,674,495, No. 3,78
5,825, British Patents 1,227,602, 1,251,345,
No. 1,267,005, No. 1,329,888, No. 1,330,932
And German Patent No. 854,890.

The amount of the o-quinonediazide compound added is preferably in the range of 1 to 50% by weight, more preferably 5 to 30% by weight, particularly preferably 10 to 30% by weight, based on the total solid content of the recording layer. These compounds can be used alone, but may be used as a mixture of several kinds. The addition amount of the additive other than the o-quinonediazide compound is preferably 1 to
It is 50% by weight, more preferably 5 to 30% by weight, and particularly preferably 10 to 30% by weight. The additive of the present invention and the binder are preferably contained in the same layer.

Further, cyclic acid anhydrides, phenols and organic acids may be used in combination for the purpose of further improving the sensitivity. Examples of cyclic acid anhydrides are phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-endooxy-Δ4-tetrahydrophthalic anhydride and tetrachlorophthalic anhydride described in U.S. Pat. No. 4,115,128. , Maleic anhydride, chloromaleic anhydride, α-phenyl maleic anhydride, succinic anhydride, pyromellitic dianhydride, etc. can be used. Examples of phenols include bisphenol A, p-nitrophenol, p-
Ethoxyphenol, 2,4,4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 "
-Trihydroxytriphenylmethane, 4,4 ',
3 ", 4" -tetrahydroxy-3,5,3 ', 5'-
Examples thereof include tetramethyltriphenylmethane. Further, as organic acids, there are JP-A-60-88942 and JP-A-2.
-96755, etc., sulfonic acids,
There are sulfinic acids, alkylsulfuric acids, phosphonic acids, phosphoric acid esters, carboxylic acids and the like. Specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethylsulfuric 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-
1,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid, ascorbic acid and the like can be mentioned. The proportion of the above cyclic acid anhydride, phenols and organic acids in the recording layer material is preferably 0.05 to 20% by weight,
It is more preferably 0.1 to 15% by weight, and particularly preferably 0.1 to 10% by weight.

In the recording layer coating liquid according to the present invention,
To extend the stability of processing under developing conditions, Japanese Patent Laid-Open No.
Nonionic surfactants as described in JP-A-2-251740 and JP-A-3-208514, and amphoteric as described in JP-A-59-121044 and JP-A-4-13149. Surfactant, EP950
A siloxane-based compound as described in Japanese Patent Application Laid-Open No. 517/517 and a fluorine-containing monomer copolymer as described in Japanese Patent Application Laid-Open No. 11-288093 can be added. Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate,
Examples thereof include sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene nonylphenyl ether and the like. Specific examples of the double-sided activator include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N.
-Tetradecyl-N, N-betaine type (for example, trade name "Amogen K": manufactured by Dai-ichi Kogyo Co., Ltd.) and the like.

As the siloxane compound, a block copolymer of dimethylsiloxane and polyalkylene oxide is preferable, and a specific example is DBE-, manufactured by Chisso Corporation.
224, DBE-621, DBE-712, DBP-7
32, DBP-534, Tego G manufactured by Tego, Germany
Examples thereof include polyalkylene oxide-modified silicone such as lid100. The ratio of the nonionic surfactant and the amphoteric surfactant in the printing plate material is 0.
05 to 15% by weight is preferable, and more preferably 0.1 to
It is 5% by weight.

In the recording layer of the present invention, a printing-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 typical example of the print-out agent is a combination of a compound that releases an acid when heated by exposure (photo-acid releasing agent) and an organic dye capable of forming a salt. Specifically, combinations of o-naphthoquinonediazide-4-sulfonic acid halogenide and a salt-forming organic dye described in JP-A Nos. 50-36209 and 53-8128, and JP-A No.
No. 3-36223, No. 54-74728, No. 60-3
No. 626, No. 61-143748, No. 61-1516.
Combinations of a trihalomethyl compound and a salt-forming organic dye described in JP-A-44 and JP-A-63-58440 can be mentioned. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent stability over time and give a clear printout image.

As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dyes. Suitable dyes include oil-soluble dyes and basic dyes, including salt-forming organic 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 (all manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl. Violet (CI42535), ethyl violet, Rhodamine B (CI145170B), malachite green (CI42000), methylene blue (CI5201).
5) etc. can be mentioned. In addition, JP-A-62-2
The dyes described in Japanese Patent No. 93247 are particularly preferable. These dyes are added in an amount of 0.01 to the total solid content of the recording layer.
It can be added to the recording layer in a proportion of from 10 to 10% by weight, preferably from 0.1 to 3% by weight. Further, if necessary, a plasticizer is added to the recording layer of the photosensitive lithographic printing plate of the present invention in order to impart flexibility to 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 oligomers and polymers, and the like are used.

The recording layer of the photosensitive lithographic printing plate of the present invention can be usually produced by dissolving each of the above components in a solvent and coating the recording layer coating solution 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, dimethoxyethane, methyl lactate, ethyl lactate, N, N-dimethylacetamide, N, N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethyl sulfoxide, Sulfolane, γ-
Examples include butyrolactone and toluene,
It is not limited to this. These solvents may be used alone or as a mixture. In selecting the coating solvent, the coating solvent for the upper recording layer should be selected so that it does not substantially dissolve the lower recording layer in order to prevent mutual compatibility at the interface between the upper recording layer and the lower recording layer. Is preferred. The concentration of the above components (total solids including additives) in the solvent is preferably 1 to 50% by weight.

As the coating method, various methods can be used, and examples thereof include bar coater coating, spin coating, spray coating, curtain coating, dip coating, air knife coating, blade coating and roll coating. You can As the coating amount decreases, the apparent sensitivity increases, but the film properties of the recording layer film deteriorate. In the recording layer of the present invention, a surfactant for improving the coatability, for example, a fluorinated surfactant as described in JP-A-62-170950 can be added. The preferable addition amount is 0.01 in the total solid content of the recording layer.
~ 1 wt%, more preferably 0.05-0.5 wt%
Is.

[Support] The support used in the photosensitive lithographic printing plate of the present invention is a dimensionally stable plate-like material having hydrophilicity and having necessary strength and durability. For example, paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, cellulose diacetate, cellulose triacetate, propion) Acid cellulose, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.),
The paper includes a metal laminated or vapor-deposited paper as described above, a plastic film, or the like.

As the support of the present invention, a polyester film or an aluminum plate is preferable, and among them, an aluminum plate which has good dimensional stability and is relatively inexpensive is particularly preferable. The preferred aluminum plate is a pure aluminum plate or an alloy plate containing aluminum as a main component and containing a slight amount of a foreign element, and may be a plastic film in which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese,
Examples include copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of foreign elements in the alloy is at most 10% by weight. Aluminum which is particularly preferred in the present invention is pure aluminum, but completely pure aluminum is difficult to produce in terms of refining technology, and thus may contain a slightly different element. As described above, the composition of the aluminum plate applied to the present invention is not specified, and conventionally known and publicly known aluminum plates can be appropriately used. The thickness of the aluminum plate used in the present invention is about 0.1 mm to 0.6 mm, preferably 0.15 mm to 0.4 mm, and particularly preferably 0.2 mm to 0.3 mm.

Prior to 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 performed 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. Further, 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. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both are combined can be used. The thus roughened aluminum plate is subjected to an alkali etching treatment and a neutralization treatment, if necessary, and then subjected to anodizing treatment if desired to enhance the water retention and abrasion 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, and sulfuric acid, phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is generally used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The treatment conditions for anodic oxidation cannot be unconditionally specified because they vary depending on the electrolyte used, but generally the concentration of the electrolyte is 1 to 80% by weight solution, the liquid temperature is 5 to 70 ° C.
A current density of 5 to 60 A / dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 seconds to 5 minutes are suitable. If the amount of the anodized film is less than 1.0 g / m ² , printing durability is insufficient, or the non-image area of the planographic printing plate is easily scratched, and ink adheres to the scratched portion during printing. So-called "scratch stains" tend to occur. After being subjected to anodizing treatment, the aluminum surface is optionally subjected to hydrophilic treatment. Examples of the hydrophilic treatment used in the present invention include US Pat.
No. 714,066, No. 3,181,461, No. 3,
There are alkali metal silicate (eg sodium silicate aqueous solution) processes such as those disclosed in 280,734 and 3,902,734. In this method, the support is immersed in an aqueous solution of sodium silicate or electrolyzed. In addition, potassium fluorozirconate disclosed in JP-B-36-22063 and U.S. Pat. Nos. 3,276,868 and 4,153,461,
For example, the method of treating with polyvinylphosphonic acid as disclosed in the above-mentioned No. 4,689,272 is used.

In the photosensitive lithographic printing plate of the present invention, two positive type recording layers are laminated on the support, but if necessary, the support and the recording layer (of a two-layer structure) An undercoat layer may be provided between the undercoat layer and the lower recording layer. Various organic compounds are used as the undercoat layer component, and examples thereof include phosphonic acids having an amino group such as carboxymethyl cellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, and phenylphosphonic acid which may have a substituent. , Naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, organic phosphonic acid such as methylenediphosphonic acid and ethylenediphosphonic acid, optionally substituted phenylphosphoric acid, naphthylphosphoric acid, alkylphosphoric acid and glycerophosphoric acid, etc. Organic phosphoric acid, phenylphosphinic acid which may have a substituent, naphthylphosphinic acid, organic phosphinic acid such as alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochloric acid of triethanolamine Has a hydroxy group such as salt -Alanine, and hydrochlorides of amines that may be used in combination of two or more.

This organic undercoat layer can be provided by the following method. That is, water or methanol, ethanol,
A method in which a solution prepared by dissolving the above organic compound in an organic solvent such as methyl ethyl ketone or a mixed solvent thereof is applied on a support and dried, and an organic solvent such as water or methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof. In a solution in which the above organic compound is dissolved, the support is immersed to adsorb the above compound, and then,
This is a method of forming an organic undercoat layer by washing with water or the like and drying. In the former method, 0.00 of the above organic compound is used.
A solution with a concentration of 5-10% by weight can be applied in various ways. In the latter method, the concentration of the solution is 0.01 to 20.
% By weight, preferably 0.05 to 5% by weight, the immersion temperature is 20 to 90 ° C., preferably 25 to 50 ° C., the immersion time is 0.1 seconds to 20 minutes, preferably 2 seconds to 1 minute. Is. The solution used for this may be adjusted to a pH range of 1 to 12 with a basic substance such as ammonia, triethylamine and potassium hydroxide, or an acidic substance such as hydrochloric acid and phosphoric acid. Further, a yellow dye may be added to improve the tone reproducibility of the photosensitive lithographic printing plate. The coating amount of the organic undercoat layer is appropriately ² to 200 mg / m ² , and preferably 5 to 100 mg / m ² . The above coating amount is 2
If it is less than mg / m ² , sufficient printing durability cannot be obtained. The same applies when the amount is larger than 200 mg / m ² .

The positive-working photosensitive lithographic printing plate prepared as described above is subjected to image exposure and development processing. As a light source of actinic rays used for image exposure, a light source having an emission wavelength in the near infrared to infrared region is preferable, and a solid laser and a semiconductor laser are preferable. The emission wavelength is 760-8
50 nm is preferred.

As a developing solution and a replenishing solution for the photosensitive lithographic printing plate of the present invention, a conventionally known alkaline aqueous solution is adjusted to have an electric conductivity suitable for each recording layer by the method described above. You can use it. Examples of the alkaline compound used in the known alkaline aqueous solution applicable to the developing solution and the replenishing solution of the photosensitive lithographic printing plate of the present invention include, for example, sodium silicate, potassium silicate, sodium triphosphate, potassium phosphate, ammonium silicate. , Dibasic sodium phosphate, potassium phosphate, ammonium phosphate, sodium carbonate,
Examples thereof include inorganic alkali salts such as potassium, ammonium, sodium hydrogen carbonate, potassium carbonate, ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium. Further, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkaline agents such as ethyleneimine, ethylenediamine and pyridine are also used. These alkaline agents may be used alone or in combination of two or more. Among these alkaline agents, a particularly preferable developer is an aqueous silicate solution such as sodium silicate or potassium silicate. The reason is that the developability can be controlled by the ratio and concentration of silicon oxide SiO ₂ which is a component of silicate and alkali metal oxide M ₂ O. For example, JP-A-54-62004, Japanese Patent Office Sho 5
Alkali metal silicates such as those described in 7-7427 are effectively used.

Furthermore, when developing using an automatic processor, an aqueous solution (replenisher) having a higher alkali strength than the developing solution is used.
It is known that a large amount of a photosensitive lithographic printing plate can be processed by replacing the developing solution in the developing tank for a long time by adding the above-mentioned to the developing solution. Also in the present invention, this replenishment system is preferably applied. Various surfactants and organic solvents can be added to the developing solution and the replenishing solution, if necessary, for the purpose of promoting or suppressing the developing property, dispersing the development residue and enhancing the ink affinity of the printing plate image area. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Further, in the developing solution and the replenishing solution, if necessary, hydroquinone, resorcin,
It is also possible to add a reducing agent such as sodium salt or potassium salt of an inorganic acid such as sulfurous acid or bisulfite, and further an organic carboxylic acid, an antifoaming agent or a water softener.

The printing plate developed using the above-mentioned developing solution and replenishing solution is post-treated with washing water, a rinse solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. As the post-treatment of the photosensitive lithographic printing plate of the present invention, various combinations of these treatments can be used.

In the photosensitive lithographic printing plate of the present invention, an unnecessary image portion (for example, of an original image film) is obtained in the lithographic printing plate obtained by imagewise exposing, developing, washing and / or rinsing and / or gumming. If there is a film edge mark or the like), the unnecessary image portion is erased. Such erasing is preferably performed, for example, by applying an erasing liquid as described in Japanese Patent Publication No. 2-13293 to the unnecessary image portion, leaving it as it is for a predetermined time, and then rinsing with water. It is also possible to use a method described in Japanese Patent Laid-Open No. 59-174842, in which an actinic ray guided by an optical fiber is applied to an unnecessary image portion and then developed.

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 the method, with a sponge or absorbent cotton soaked with the surface-adjusting solution, it is applied on the lithographic printing plate, or by immersing the printing plate in a vat filled with the surface-adjusting solution, 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 coating amount of the surface conditioning solution is generally 0.03 to 0.8.
g / m ² (dry weight) is suitable. The planographic printing plate coated with the surface-adjusting solution is dried if necessary, and then a burning processor (for example, a burning processor sold by Fuji Photo Film Co., Ltd .: “BP-130”).
0 ") and so on. The heating temperature and time in this case depend on the types of components forming the image,
The range of 180 to 300 ° C. and the range of 1 to 20 minutes are preferable.

The planographic 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-treating treatment containing a water-soluble polymer compound or the like. When a liquid is used, so-called desensitizing treatment such as gumming can be omitted.
The planographic printing plate obtained by such treatment is applied to an offset printing machine or the like and used for printing a large number of sheets.

[0094]

[Undercoat liquid]

  ・ The following compound 0.3g   ・ Methanol 100g   ・ Water 1g

[0095]

[Chemical 14]

The following coating liquid for lower recording layer was applied to the obtained substrate so that the coating amount was 0.75 g / m ^2, and then T
PERFECT OPEN PH200, manufactured by ABAI
Set Wind Control to 7 at 140 ℃
At 50 ° C for 50 seconds, and then the coating liquid for the upper recording layer is coated at a coating amount of 0.3 g / m ² and then at 120 ° C.
And dried for 1 minute to obtain a photosensitive lithographic printing plate.

[0097] [Coating liquid for lower recording layer] ・ N- (4-aminosulfonylphenyl) methacrylamide /     Acrylonitrile / methyl methacrylate     (36/34/30: weight average molecular weight 50,000) 1.896 g -Cresol novolac (m / p = 6/4 weight average molecular weight 4500,       Residual monomer 0.8wt%) 0.237g Infrared absorbing agent (exemplary compound IR-1) 0.109 g * 4,4'- bishydroxy phenyl sulfone 0.063g ・ Tetrahydrophthalic anhydride 0.190g -P-toluenesulfonic acid 0.008 g ・ Ethyl violet counter ion     Changed to 6-hydroxynaphthalene sulfonic acid 0.05g ・ Fluorosurfactant (MegaFac F176,     Dainippon Ink and Co., Ltd.) 0.035g ・ Methyl ethyl ketone 26.6g ・ 1-Methoxy-2-propanol 13.6 g * Γ-butyrolactone 13.8 g

[0098] [Coating liquid for upper recording layer] -M, p-cresol novolac (m / p ratio = 6/4, weight average molecular weight     4500, containing 0.8% by weight of unreacted cresol) 0.237 g Infrared absorber (exemplary compound IR-1) 0.047 g ・ Dodecyl stearate 0.060g ・ 3-Methoxy-4-diazodiphenylamine     Hexafluorophosphate 0.030 g ・ Fluorosurfactant (MegaFac F176,     Dainippon Ink and Chemicals Co., Ltd. 0.110g -Fluorine-based surfactant (MegaFac MCF312 (30%),     Dainippon Ink Industry Co., Ltd.) 0.120 g ・ Methyl ethyl ketone 15.1 g ・ 1-Methoxy-2-propanol 7.7 g

Comparative Example 1 The infrared absorber compounded in the lower and upper recording layer coating solutions used in Example 1 was changed to IR-792 perchlorate (manufactured by Sigma-Aldrich Japan KK) having the following structure. A photosensitive lithographic printing plate was obtained in the same manner as in Example 1 except for the above.

[0100]

[Chemical 15]

COMPARATIVE EXAMPLE 2 Example 1 The following recording layer coating solution 2 was applied to the same substrate to give a coating amount of 1.0 g / m ² and then dried at 140 ° C. for 50 seconds to perform photosensitive lithographic printing. Got the edition.

[0102] [Coating liquid for recording layer 2] ・ N- (4-aminosulfonylphenyl) methacrylamide /     Acrylonitrile / methyl methacrylate     (35/35/30: weight average molecular weight 50,000) 1.896 g -Cresol novolac (m / p = 6/4 weight average molecular weight 4500,       Residual monomer 0.8wt%) 0.332g Infrared absorbing agent (exemplary compound IR-1) 0.155 g * 4,4'-bishydroxyphenyl sulfone 0.063g ・ Tetrahydrophthalic anhydride 0.190g -P-toluenesulfonic acid 0.008 g ・ Ethyl violet counter ion     Changed to 6-hydroxynaphthalene sulfonic acid 0.05g ・ Fluorosurfactant (MegaFac F176,     Manufactured by Dainippon Ink Industry Co., Ltd.) 0.145 g -Fluorine-based surfactant (Megafac MCF-312 (30%),     Dainippon Ink Industry Co., Ltd.) 0.120 g ・ Methyl ethyl ketone 26.6g ・ 1-Methoxy-2-propanol 13.6 g * Γ-butyrolactone 13.8 g

(Examples 2 to 6) A photosensitive lithographic printing plate was prepared in the same manner as in Example 1 except that the coating liquids for the lower and upper recording layers were changed to the exemplified compounds shown in Table 1 below. Got

[Evaluation of photosensitive lithographic printing plate] [Evaluation of development latitude] The photosensitive lithographic printing plate thus obtained was drawn on a test pattern image with a Trendsetter manufactured by Creo at a beam intensity of 9 w and a drum rotation speed of 150 rpm. I got involved. After that, using a Fuji Photo Film Co., Ltd. PS processor 900H, which was prepared by changing the dilution ratio of Fuji Photo Film Co., Ltd. developer DT-1, the liquid temperature was kept at 30 ° C. and the development time was 12 seconds. did. This time,
Develop the difference between the one with the highest conductivity and the one with the lowest conductivity, in which the image area was not eluted and there was no stain or coloration due to the residual film of the recording layer that was poorly developed and good development was possible. It was evaluated as latitude. The results are shown in Table 1 below.

[Ablation Evaluation] Further, the obtained photosensitive lithographic printing plate was treated with an output of 500 mW, a wavelength of 830 nm, and
After exposure with a semiconductor laser having a beam diameter of 17 μm (1 / e ² ) at a main scanning speed of 5 m / sec, the presence or absence of ablation was visually evaluated. The results are shown in Table 1 below.

[0106]

[Table 1]

[0107]

The photosensitive lithographic printing plate of the present invention has at least two recording layers, and at least one of the recording layers has two or more chromophores capable of absorbing infrared rays in the same molecule. By containing an infrared absorbing agent in which the chromophore is bonded by a covalent bond, it is possible to realize a direct plate making which is excellent in development latitude during image formation and which can form a good image by exposure to an infrared laser.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ippei Nakamura             Fuji-Sha, 4000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture             Shin Film Co., Ltd. F term (reference) 2H025 AA01 AA04 AB03 AC08 AD03                       CB14 CB15 CB29 CB52 CC20                       FA03 FA17                 2H096 AA07 AA08 BA11 BA16 BA20                       EA04 GA08 KA02 KA03 KA06

Claims (2)

[Claims] 1. A photosensitive lithographic printing plate comprising, on a hydrophilic support, at least two recording layers whose solubility in an alkaline aqueous solution is increased by infrared light, the photosensitive lithographic printing plate comprising at least one recording layer. A photosensitive lithographic printing plate comprising an infrared absorbing agent having two or more chromophores capable of absorbing infrared rays in the same molecule and having the chromophores bound by a covalent bond. 2. The photosensitive lithographic printing plate according to claim 1, wherein the infrared absorber is represented by the following general formula (I). (D) _n- A general formula (I) (In the formula, A represents a divalent or higher valent organic group, n represents an integer of 2 or more. D represents a chromophore having absorption in the infrared region,
Each of the two or more chromophores may be the same or different. When the chromophore moiety has a charge, it may be accompanied by an ion having a charge opposite to that of the chromophore for neutralizing the charge. )