JP2002244278A - Printing plate for laser exposure and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a directly laser-writable planographic printing plate having high adhesive strength of a photosensitive layer to the substrate and excellent in printing resistance. SOLUTION: The printing plate for laser exposure is obtained by forming a photosensitive layer comprising a photopolymerizable composition containing (a) an ethylenically unsaturated compound and (b) a photopolymerization initiator on a substrate and the kurtosis degree Sku of the surface height distribution of the substrate is >=2.8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing plate for laser exposure. More specifically, the present invention relates to a lithographic printing plate support having excellent printing durability in printing using an aluminum or alloy plate thereof.

[0002]

2. Description of the Related Art Conventionally, lithographic printing plates are widely known and have various photosensitive layers. In the case of a negative type, there are a diazo resin-containing type, a photopolymerization type, a photocrosslinking type and the like. In order to prepare such a lithographic printing plate, it is common to place a transparent negative film original (lith film) on these lithographic printing plates and to expose the image using ultraviolet light. It took time and effort. In recent years, with the development of image forming technology, a photopolymer having high photosensitivity to light in the visible region has been demanded. It is a photosensitive material suitable for, for example, non-contact type projection exposure plate making or visible light laser plate making, and a photopolymerization system has the highest sensitivity. As the visible light laser, 488, 514.5 nm light of an Ar laser and second harmonic light (SHG-LD, 350 to 6) of a semiconductor laser are used.
00 nm), 532 nm light of an SHG-YAG laser and the like can be used. Therefore, by using a kind of high-sensitivity photopolymerizable photosensitive layer in the photosensitive layer, a laser beam with a narrow beam is scanned over the plate surface, and character documents, image documents, etc. are formed directly on the plate surface, Plate making can be performed directly without using a manuscript. For example, by using the photosensitive composition described in JP-B-61-9621, JP-A-63-178105, JP-A-2-244050, etc., it is possible to directly make a plate without using a film original.

[0003]

However, such a conventional printing plate for laser exposure which has high sensitivity and photopolymerizability does not always have strong adhesion between the photosensitive layer and the support. In this case, a solid image may be missing or a thin line or a highlight portion may fly. The surface microstructure of the support has been devised in order to make the adhesion between the photosensitive layer and the support sufficiently strong.However, for printing plates for laser exposure, surface structures with sufficient printing Could not be obtained. Accordingly, the present invention provides a support for a negative-type photopolymerizable lithographic printing plate capable of realizing a strong adhesion between the photosensitive layer and the support and having excellent printing durability and capable of directly laser writing, and a method for producing the same. Aim.

[0004]

Means for Solving the Problems In a lithographic printing plate using a photosensitive layer of a photopolymerizable composition, the inventors of the present invention can carry out photochemically roughening and desmutting steps under appropriate conditions. It has been found that a lithographic printing plate having an enhanced anchoring effect on the layer and an increased adhesion and having excellent printing durability can be obtained. That is, the first gist of the present invention is that
A printing plate for laser exposure on which a photosensitive layer composed of a photopolymerizable composition containing (a) an ethylenically unsaturated compound and (b) a photopolymerization initiator is formed, and as a support, the surface height thereof A printing plate for laser exposure, characterized in that a material having a distribution sharpness Sku of 2.8 or more is used.

A second gist of the present invention is that a photosensitive layer comprising a photopolymerizable composition containing (a) an ethylenically unsaturated compound and (b) a photopolymerization initiator is formed on a support. A printing plate for laser exposure to be used, wherein the support has a surface height distribution with a degree of distortion Ssk of -0.45 or less. Furthermore, a third aspect of the present invention is a laser in which a photosensitive layer comprising a photopolymerizable composition containing (a) an ethylenically unsaturated compound and (b) a photopolymerization initiator is formed on a support. An exposure printing plate, wherein a support having a root mean square (RMS) deviation Sq of 0.6 μm or more is used as a support.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a printing plate for laser exposure in which a photosensitive layer comprising a photopolymerizable composition is formed on a support. It is characterized by using a material having a surface shape of This parameter is
3D surface roughness parameters (Birmingham set of 14 par) specified in the report by the committee of munities
amerters: KJStout, PJSullivan, WPDong, E.Mani
sh, N. Luo, T. Mathia & H. Zahouani: The Development o
f Methods for the Characterization of Roughness in
Three-Dimensions, Report EUR 15178 EN of the Comm
Among the ision of European Communities (1994) 358), the sharpness (kurtosis) Sku of the surface height distribution of the support, which is a statistical parameter of the amplitude and height distribution, and the skewness (skewness) of the surface height distribution It is defined by Ssk and the root mean square (RMS) deviation Sq of its surface. Hereinafter, each parameter will be described. S _ku : Krutosis of Surface Height Distribution
Height Distribution: A measure of the sharpness of a surface shape curved surface, which characterizes the spread of a surface height distribution and is defined by the following equation.

[0007]

(Equation 1) This is obtained by calculating the fourth moment of the surface shape curved surface. In digital form, it is expressed by the following equation.

[0008]

(Equation 2)

When S _ku = 3, it indicates a normal distribution. When S _ku <3, the surface height distribution has a collapsed shape. When S _ku > 3, the distribution is sharp. To indicate that FIG. 1 shows the distribution according to the difference in the value of _Sku .

In the present invention, the sharpness Sku of the surface height distribution of the support is 2.8 or more, preferably 2.9 or more.
More preferably, those having a value of 3.0 or more are used. The upper limit is not particularly limited, but is 5.0 or less, preferably 4.5 or less, and more preferably 4.0 or less. S _sk : Skewness of Surface Height Distribution
Height Distribution) It indicates the symmetry of the surface curved surface with respect to the average plane, and indicates the degree of distortion of the surface height distribution. S _sk is defined by the following equation.

[0011]

(Equation 3)

As can be seen from this equation, the third moment of the curved surface is calculated. In digital form, it is expressed by the following equation.

[0013]

(Equation 4)

FIG. 2 shows the distribution according to the difference in the value of _Ssk . When S _sk = 0, it indicates that the surface height distribution is symmetric with respect to the average line. When S _sk <0, the surface height distribution is deviated upward with respect to the average plane, and S _sk > 0
Indicates that the opposite is true. In the present invention, the degree of distortion Ssk of the surface height distribution of the support is -0.4.
5 or less, preferably -0.60 or less, more preferably-
Those having a value of 0.70 or less, particularly -0.80 or less, are used. The upper limit is not particularly limited, but is usually -2.0 or more, preferably -1.8 or more, and more preferably -1.5 or more.
The above is good. _Sq : Root-Mean-Square Deviatio
n) A three-dimensional extension of two-dimensional Rq (RMS). This represents the standard deviation σ in statistics. The root mean square deviation is obtained by dividing the volume between the curved surface and the average surface by the square of the distance between the surface shape curved surface and the average surface, and calculating the square root after dividing the volume of the portion sandwiched by the average surface by the measured area. The average plane is the XY plane,
The vertical direction is the Z axis, and the measured surface shape curve is z = f
When (x, y) is used, it is defined by the following equation.

[0015]

(Equation 5)

Here, L _x : measurement length in the x direction L _y : y
Direction measurement length Normally, discrete data format (digital) measured by measuring instrument
Then, the following equation is obtained.

(Equation 6) This parameter is insensitive to sampling interval, but 2D
If a filter is used, it is sensitive to the size of the sampling area and its frequency band (cutoff). In the present invention, a support having a root mean square (RMS) deviation Sq of 0.6 μm or more, preferably 0.62 μm or more, more preferably 0.65 μm or more is used.
The upper limit is not particularly limited, but is usually 2.0 μm or less,
Preferably 1.5 μm or less, more preferably 1.2 μm
The following is good.

As the support of the present invention, aluminum,
Metal plate such as zinc, copper, steel, aluminum, zinc, copper,
Metal plates plated or evaporated with iron, chromium, nickel, etc.
Examples include paper, paper coated with resin, paper to which metal foil such as aluminum is adhered, plastic film, plastic film subjected to hydrophilic treatment, and glass plate. Inside,
Preferred is an aluminum plate. Hereinafter, the method for producing a support having a specific surface shape according to the present invention will be described by taking an aluminum support as an example.

The aluminum support according to the present invention can be manufactured by electrochemically roughening an aluminum plate. As the aluminum plate, any of an aluminum plate and an aluminum alloy plate can be used. An example of a preferred aluminum plate is JIS5002
1050 material (Fe: 0.5% by weight or less, Si: 0.5% by weight)
Wt% or less, aluminum: 99.5 wt% or more). The aluminum plate is preferably subjected to alkali etching after washing with a solvent or the like to remove the adhering rolling oil and the like. The alkali etching may be usually performed using a 0.5 to 40% by weight aqueous solution such as sodium hydroxide or potassium hydroxide at 40 to 90 ° C. for 3 to 20 seconds.

Since the aluminum plate which has been subjected to the alkali etching has an alkali-insoluble smut on the surface, the smut is removed by treatment with sulfuric acid, phosphoric acid, nitric acid, chromic acid or the like. Treatment is preferably performed with a sulfuric acid aqueous solution of about 10% by weight for about 0.5 to 30 seconds, preferably for about 0.5 to 10 seconds. The treatment with the aqueous acid solution is preferably performed at 30 to 40 ° C. Although the reason is unknown, by heating the acid, it is possible to form a surface state excellent in printing durability on the aluminum support. The aluminum plate that has undergone acid removal from the smut is then subjected to an electrochemical graining treatment. It is preferable to use an aqueous hydrochloric acid solution as the electrolytic solution. If desired, an inorganic acid such as nitric acid or sulfuric acid or an organic acid such as citric acid or tartaric acid may be added. Usually 0.
An aqueous solution of hydrochloric acid of 1 to 10% by weight, preferably 0.5 to 3% by weight is used. Although aluminum ions are accumulated in the electrolytic solution during the electrolytic treatment, the amount of aluminum ions in the electrolytic solution is preferably controlled to 1 to 6 g / L, particularly preferably 2 to 5 g / L.

The current density and the treatment time during the electrolytic treatment also greatly affect the surface condition formed on the aluminum support. From the viewpoint of productivity, it is general that the electrolytic treatment is performed at a large current density in a short time, but in order to obtain the aluminum support according to the present invention, the electrolytic treatment is performed at a relatively small current density for a relatively long time. There is a need to do. Usually 50 or 6
Using a commercial alternating current of 0 Hz, usually 50 to 170 A / dm
² , preferably at a current density of 70 to 150 A / dm ² , the electrolysis may be performed usually for 4 to 18 seconds, preferably 6 to 14 seconds. However, it is not practical to further reduce the current density and perform the electrolytic treatment for a longer time because the productivity is reduced.

The aluminum plate which has been subjected to electrochemical graining is then subjected to desmut treatment with an acid or alkali aqueous solution. The aluminum plate that has been subjected to electrochemical surface roughening is first treated with an aqueous alkaline solution. The concentration of the alkaline aqueous solution is usually 0.01 to 3%, preferably 0.1 to
1.0%, the temperature is usually 0 to 80 ° C., preferably 20 to 60 ° C., and the treatment time is preferably 0.1 to 80 ° C.
60 seconds. The components used in the alkaline aqueous solution are not particularly limited, but sodium hydroxide is preferred.

Further, it is preferable to treat with an acid in order to remove remaining alkali-free smut. The acid is not particularly limited, but an aqueous sulfuric acid solution is preferred. As for the condition of the acid, the acid concentration is usually 0.01% to 100%, preferably 5%.
-30%, and the temperature is usually 0-80 ° C, preferably 2
0 to 50 ° C, and the processing time is 0.1 to 60 seconds.
The subsequent anodic oxidation step is usually performed in a sulfuric acid aqueous solution using a direct current.However, it is performed in an aqueous solution of phosphoric acid, chromic acid, sulfamic acid, benzenesulfonic acid, or the like, or a solution obtained by adding these acids to a sulfuric acid aqueous solution. It can also be performed as an electrolyte. Although it varies greatly depending on the electrolyte used for the anodic oxidation conditions, in general, the electrolyte concentration is 1 to 40% by weight and the solution temperature is 5%.
~ 70 ° C, current density 0.5 ~ 70A / dm ² , voltage 10
５０50 V, electrolysis time is 5 seconds to 30 seconds. After the anodization, the support manufactured in this manner may be subjected to a sealing treatment by a conventional method such as a hot water treatment, a sodium silicate treatment, an immersion treatment in an aqueous solution containing an acetate salt and a hydrophilic polymer compound. Means that the amount of smut remaining on the surface is usually 0.5 mg
/ Dm ² or more, preferably 3 mg / dm ² or more, particularly preferably 5 mg / dm ² or more.

The photosensitive lithographic printing plate according to the present invention is obtained by forming a photopolymerizable photosensitive layer on a support having a specific surface shape obtained by the above method. The photopolymerizable composition forming the photosensitive layer contains (a) an ethylenically unsaturated compound and (b) a photopolymerization initiation system. The ethylenically unsaturated compound as the component (a) constituting the photopolymerizable composition of the present invention can be used as a photopolymerization initiation system for the component (b) described below when the photopolymerizable composition is irradiated with actinic rays. Means a monomer having an ethylenically unsaturated double bond, which is addition-polymerized and possibly crosslinked and cured by the action of, and a polymer having such a double bond in a main chain or a side chain. In addition, the meaning of the monomer here is a concept corresponding to a so-called polymer, and in addition to a monomer in a narrow sense, includes a dimer, a trimer, and other oligomers. is there.

Specific examples of these monomers include (1) acrylic acid and methacrylic acid (both of which may be collectively referred to as “(meth) acrylic acid”). Unsaturated carboxylic acids, (2) these alkyl esters, (3) ethylene glycol di (meth) acrylate,
Diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, Pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerol di (meth) acrylate, glycerol tri (meth) acrylate, and Esters of the same aliphatic polyhydroxy compounds as itaconate, crotonate, maleate and the like with unsaturated carboxylic acids; Esters of aromatic polyhydroxy compounds such as quinone di (meth) acrylate, resorcin di (meth) acrylate, pyrogallol tri (meth) acrylate and unsaturated carboxylic acids, (5) ethylene glycol, (meth) acrylic acid and phthalic acid Of diethylene glycol, (meth) acrylic acid and maleic acid, condensate of pentaerythritol, (meth) acrylic acid and terephthalic acid, and of butanediol, glycerin, (meth) acrylic acid and adipic acid Condensates of polyhydroxy compounds such as condensates with unsaturated carboxylic acids and polycarboxylic acids, (6) polyisocyanate compounds such as tolylene diisocyanate and hydroxyethyl (meth)
Urethane (meth) acrylates such as addition products with hydroxyl group-containing (meth) acrylates such as acrylates, (7)
(8) Epoxy such as an addition reaction product of a polyisocyanate compound and a hydroxyl group-containing vinyl compound, such as a vinyl urethane; (8) an addition reaction product of a polyvalent epoxy compound with a hydroxyl group-containing (meth) acrylate such as hydroxyethyl (meth) acrylate; (Meth) acrylates, (9) acrylamides such as ethylenebis (meth) acrylamide, (10) allyl esters such as diallyl phthalate, (11) vinyl group-containing compounds such as divinyl phthalate, (12) (meth) acryloyl And (meth) acryloyl group-containing phosphates such as oxyethyl phosphate and bis ((meth) acryloyloxyethyl) phosphate.

As the polymer, specifically, for example, those having a double bond in the main chain, (1) polyesters obtained by a polycondensation reaction between an unsaturated dicarboxylic acid and a dihydroxy compound, 2) Polyamides obtained by a polycondensation reaction between an unsaturated dicarboxylic acid and a diamine compound, such as polyamides having a double bond in a side chain, (3) itaconic acid, ethylidene malonic acid, propylidene succinic acid, etc. and a dihydroxy compound (4) Polyamides obtained by polycondensation reaction of itaconic acid, ethylidene malonic acid, propylidene succinic acid, etc. with diamine compound, (5) polyvinyl alcohol, poly (2- Hydroxyethyl methacrylate), polyepichlorohydrin and other side chains with hydroxyl groups and methyl halide groups A polymer obtained by a reaction between the polymer and the unsaturated carboxylic acids having active functional groups,
And the like.

Next, the photopolymerization initiation system used when used as a photopolymerizable composition will be described. The photopolymerization initiation system is usually composed of a radical generator and a sensitizer, and optionally contains a polymerization accelerator. As the radical generator, any of those capable of initiating the polymerization of the ethylenic monomer can be used. Among them, examples of the radical generator that generates an active radical by interacting with a photoexcited sensitizer include, for example, titanocenes, hexaarylbiimidazoles, organic boron anions (borates), and halogenated carbons. Hydrogen derivatives (halomethyl group-containing compounds), diaryliodonium salts, organic peroxides, and the like can be given.

As the titanocenes, for example, JP-A-59
And the like. Any of various titanocenes described in JP-A-152396 and JP-A-61-151197 can be appropriately used. More specifically, di-cyclopentadienyl-Ti-di-chloride, di-cyclopentadienyl-Ti-bis-phenyl, di-cyclopentadienyl-Ti-bis-2,3,4,5 , 6-Pentafluorophenyl-1-yl, di-cyclopentadienyl-Ti-
Bis-2,3,5,6-tetrafluorophenyl-1-yl, di-cyclopentadienyl-Ti-bis-2,4,
6-trifluorophenyl-1-yl, dicyclopentadienyl-Ti-2,6-difluorophenyl-1-yl, di-cyclopentadienyl-Ti-bis-2,4-
Di-fluorophenyl-1-yl, di-methylcyclopentadienyl-Ti-bis-2,3,4,5,6-tetrafluorophenyl-1-yl, di-methylcyclopentadienyl-Ti-bis -2,6-difluorophenyl-1-
Yl, di-cyclopentadienyl-Ti-bis-2,6
-Difluoro-3- (pyr-1-yl) -phenyl-1-
Titanocene compounds having a dicyclopentadienyl group such as yl can be mentioned. These may be used in combination of two or more.

Hexaarylbiimidazoles include, for example, 2,2'-bis (o-chlorophenyl)-
4,4 ', 5,5'-tetra (p-fluorophenyl)
Biimidazole, 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetra (p-iodophenyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4 , 4 ', 5,5'-Tetra (p-chloronaphthyl) biimidazole, 2,2'-bis (o-chlorophenyl) -4,4'5,5'-tetra (p-chlorophenyl) biimidazole , 2,2'-bis (o-bromophenyl) -4,4 ', 5,5'-tetra (p-chloro-
p-methoxyphenyl) biimidazole, 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetra (o, p-dichlorophenyl) biimidazole,
2'-bis (o-chlorophenyl) -4,4'5,5 '
-Tetra (o, p-dibromophenyl) biimidazole, 2,2'-bis (o-bromophenyl) -4,4 '
5,5′-tetra (o, p-dichlorophenyl) biimidazole, 2,2′-bis (o, p-dichlorophenyl) -4,4′5,5′-tetra (o, p-di Hexaarylbiimidazoles having a halogen substituent on the benzene ring such as (chlorophenyl) biimidazoles are preferred.

These hexaarylbiimidazoles can be used in combination with various kinds of biimidazoles, if necessary. Biimidazoles are, for example, Bul
l. Chem. Soc. Japan. 33,565 (1
960) and J.M. Org. Chem. 36 [16] 22
62 (1971).

Examples of the organic boron anion include, for example, JP-A Nos. 62-143044 and 62-150242.
JP-A-9-188865, JP-A-9-18868
6, JP-A-9-188710, and Patent No. 276476.
9 and Kunz, Martin "Rad Tech'98.Pr
Oceding April 19-22, 1998, Chicago "and the like, and particularly preferably those represented by the following general formula (IV).

[0031]

Embedded image

[In the formula (IV), R ² , R ³ , R ⁴ and R ⁵
Are each independently an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an alkynyl group which may have a substituent, A good aryl group or a heterocyclic group is shown, which may be linked to each other to form a cyclic structure, and at least one of them is an alkyl group which may have a substituent. ]

Here, when R ² , R ³ , R ⁴ and R ⁵ in the formula (IV) are alkyl groups, the number of carbon atoms is usually 1 to 1.
5, preferably 1 to 5, the number of carbon atoms when it is an alkenyl group or an alkynyl group is usually 2 to 15, preferably 2 to 5,
When it is an aryl group, it usually has 6 to 20, preferably 6 to 15, and when it is a heterocyclic group, it usually has 4 to 4 carbon atoms.
20, preferably 4 to 15, and examples of the substituent therefor include a halogen atom, an alkyl group, an alkoxy group, a trifluoromethyl group, and a trimethylsilyl group. Among them, R ^{2 to} R ⁴ are independently a phenyl group optionally substituted with a halogen atom, and R ⁵ has 1 carbon atom.
It is preferably an alkyl group of from 6 to 6.

Specific examples of these organic boron anions include, for example, n-butyl-methyl-diphenyl boron anion, n-butyl-triphenyl boron anion,
-Butyl-tris (2,4,6-trimethylphenyl)
Boron anion, n-butyl-tris (p-methoxyphenyl) boron anion, n-butyl-tris (p-fluorophenyl) boron anion, n-butyl-tris (m-
Fluorophenyl) boron anion, n-butyl-tris (2,6-difluorophenyl) boron anion, n-butyl-tris (2,4,6-trifluorophenyl) boron anion, n-butyl-tris (2,3 , 4,5,6
-Pentafluorophenyl) boron anion, n-butyl-tris (p-chlorophenyl) boron anion, n-butyl-tris (trifluoromethyl) boron anion, n
-Butyl-tris (2,6-difluoro-3-pyrrolylphenyl) -boron anion;

Examples of counter cations include onium compounds such as alkali metal cations, ammonium cations, phosphonium cations, sulfonium cations, and iodonium cations, and pyrylium cations, thiapyrylium cations, and indolium cations. However, an organic ammonium cation such as a tetraalkylammonium is preferable, and particularly a C1-6
The tetraalkylammonium cation of the alkyl group is preferred.

Examples of the halomethyl group-containing compound include mono,
An s-triazine compound in which a di- or trihalogen-substituted methyl group is bonded to an s-triazine ring is preferable, and a compound represented by the following general formula (V) is particularly preferable.

[0037]

Embedded image

[In the formula (V), X represents a halogen atom,
W represents an aryl group or a heterocyclic group which may have a substituent, and R ⁶ represents a hydrogen atom, a halogen atom, an alkyl group,
Or an aryl group, and r is an integer of 0-2. ]

These s-triazine compounds include:
Specifically, for example, 2-methyl-4,6-bis (trichloromethyl) -s-triazine, 2-n-propyl-
4,6-bis (trichloromethyl) -s-triazine,
2- (α, α, β-trichloroethyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p- Methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3,4-epoxyphenyl) -4,6-bis (trichloromethyl)
-S-triazine, 2- (p-chlorophenyl) -4,
6-bis (trichloromethyl) -s-triazine, 2-
[1- (p-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2-styryl-4,6-bis (trichloromethyl) -s-triazine, -(P-methoxystyryl)
-4,6-bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl) -4,6
-Bis (trichloromethyl) -s-triazine, 2-
(P-tolyl) -4,6-bis (trichloromethyl)-
s-triazine, 2- (4-methoxynaphthyl) -4,
6-bis (trichloromethyl) -s-triazine, 2-
Phenylthio-4,6-bis (trichloromethyl) -s
-Triazine, 2-benzylthio-4,6-bis (trichloromethyl) -s-triazine, 2-methyl-4,6
-Bis (tribromomethyl) -s-triazine, 2-methoxy-4,6-bis (tribromomethyl) -s-triazine and the like, among which 2-methyl-4,6-bis (trichloromethyl) -S-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2- (3 , 4-Epoxyphenyl) -4,6-bis (trichloromethyl)
-S-triazine, 2- [1- (p-methoxyphenyl) -2,4-butadienyl] -4,6-bis (trichloromethyl) -s-triazine, 2- (p-methoxystyryl) -4,6 -Bis (trichloromethyl) -s-triazine, 2- (pi-propyloxystyryl)-
4,6-bis (trichloromethyl) -s-triazine and the like are preferable because of excellent stability over time.

These radical generators can be appropriately selected and used depending on the exposure wavelength. For example, when the exposure wavelength is in the range of 350 to 650 nm, titanocenes and / or
Alternatively, the use of hexaarylbiimidazoles is particularly preferable because sensitivity, storage stability, adhesion to a coating film base, and the like are particularly good. When the exposure wavelength is 650 to 1300 nm, the use of an organic boron anion and / or a halomethyl group-containing compound is particularly preferred because sensitivity, preservability, adhesion to a coating film base, and the like are particularly good. Next, the sensitizer in the photopolymerization initiation system will be described. The sensitizer in the present invention,
It means a compound capable of effectively generating an active radical upon irradiation with light when coexisting with the above-mentioned activator.

Examples of typical sensitizers include, for example, triphenylmethane leuco dyes such as leuco crystal violet and leucomalachite green disclosed in US Pat. No. 3,479,185, and erythrosine. Photoreducing dyes such as Eosin Y and US Pat. No. 3,549,367; US Pat.
Aminophenyl ketones such as Michler's ketone and aminostyryl ketone disclosed in US Pat.
The β-type disclosed in U.S. Pat. No. 3,844,790 is disclosed.
Diketones, indanones described in U.S. Pat. No. 4,162,162, ketocoumarins described in JP-A-52-112681, and JP-A-59-56403.
No. 4,594,3, disclosed in US Pat. No. 4,594,311.
No. 10, aminophenyl heterocycles, U.S. Pat. No. 4,966,830, julolidine heterocycles, pyromethene dyes described in JP-A-5-241338, other cyanine dyes, And dialkylbenzene compounds.

These sensitizers can be appropriately selected and used depending on the exposure wavelength.
If m, a dialkylbenzene-based compound is preferable,
If the exposure wavelength is 400 to 650 nm, ketocoumarins and pyromethene dyes are preferred, and the exposure wavelength is 650.
If it is 〜1300 nm, a cyanine dye is preferred.

The dialkylaminobenzene-based compound has a dialkylaminobenzene structure and may have any substituent. Among them, the dialkylaminobenzophenone-based compound and p-amino group on the benzene ring Dialkylaminobenzene compounds having an aromatic heterocyclic group as a substituent at the carbon atom at the 1-position, and the alkyl groups constituting the dialkylamino group of these compounds are bonded to each other, and / or the alkyl group is located on the benzene ring. And a compound having a structure in which a nitrogen-containing heterocyclic structure is formed by bonding to a carbon atom adjacent to the carbon atom to which the amino group is bonded. In the above, the amino groups constituting the dialkylamino group may be the same or different, and preferably have 1 to 6 carbon atoms.

Among them, preferred dialkylaminobenzene compounds are represented by the following formulas (VI) and (VII).

[0045]

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(In the formula (VI), R ^{7 to} R ¹⁰ each independently represent an alkyl group having 1 to 6 carbon atoms, and R ^{11 to} R 10
¹⁴ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, wherein R ⁷ and R ⁸ , R ⁹ and R ¹⁰ , R ⁷ and R ¹¹ , R ⁸ and R ¹² , R ⁹
And R ¹³ and R ¹⁰ and R ¹⁴ may be independently bonded to each other to form a ring. )

[0047]

Embedded image

(In the formula (VII), R ¹⁵ and R ¹⁶ are each independently an alkyl group having 1 to 6 carbon atoms, and R ¹⁷ and R ¹⁸ are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. To Q
Is an oxygen atom, a sulfur atom, a dialkylmethine group, or-
N (R ¹⁹ ) —, wherein R ¹⁹ is a hydrogen atom or carbon 1-6
Represents an alkyl group. However, R ¹⁵ and R ¹⁶ , R ¹⁵ and R ¹⁷ or R ¹⁶ and R ¹⁸ may be independently bonded to form a ring. ) The alkyl group of the dialkylmethylene has 1 to 6 carbon atoms, preferably 1. Formulas (VI) and (VI
When any one of R ^{7 to} R ¹⁸ in I) is bonded to form a ring, the ring is preferably a 5- or 6-membered ring, particularly preferably a 6-membered ring. As the compound represented by the formula (VI),
4,4'-dimethylaminobenzophenone, 4,4'-
Examples include diethylaminobenzophenone and compounds having the following structure.

[0049]

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The compounds represented by the general formula (V) include 2- (p-dimethylaminophenyl) benzoxazole, 2- (p-diethylaminophenyl) benzoxazole, and 2- (p-dimethylaminophenyl) Benzo [4,5] benzoxazole, 2- (p-
Dimethylaminophenyl) benzo [6,7] benzoxazole, 2,5-bis (p-diethylaminophenyl) 1,3,4-oxazole, 2- (p-dimethylaminophenyl) benzothiazole, 2- (p-diethylamino Phenyl) benzothiazole, 2- (p-dimethylaminophenyl) benzimidazole, 2- (p-diethylaminophenyl) benzimidazole and compounds having the following structure.

[0051]

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The cyanine dye has a basic structure in which a heteroatom such as a nitrogen atom, an oxygen atom, or a sulfur atom is bonded by a polymethine (-CH =) n chain. A so-called cyanine-based dye in a broad sense having a structure in which atoms form a heterocycle and a heterocycle is bonded via a polymethine chain as a basic structure, specifically, for example, quinoline-based (so-called cyanine-based), indole-based (So-called indocyanine-based), benzothiazole-based (so-called thiocyanine-based), pyrylium-based, thiapyrylium-based, squarylium-based, croconium-based, azurenium-based, and the like, and an acyclic heteroatom bonded through a polymethine chain. Examples include a so-called polymethine dye having a structure, and among them, an indole dye and a benzothiazole dye are preferable. As the indole-based and benzothiazole-based dyes, those represented by the following general formula (VIII) are particularly preferable.

[0053]

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[In the formula (VIII), Y ¹ and Y ² each independently represent a dialkylmethylene group or a sulfur atom;
²⁰ and R ²¹ are each independently an alkyl group which may have a substituent, an alkenyl group which may have a substituent,
An alkynyl group which may have a substituent or a phenyl group which may have a substituent is shown, and a penta, hepta, nona, or undecamethine group which may have an L1 substituent is shown. The two substituents on the penta, hepta, nona, or undecamethine group are linked to each other and have 5 to 7 carbon atoms.
May form a cycloalkene ring, a cycloalkeneone ring, a cycloalkenedione ring, or a cycloalkenethione ring, and the fused benzene ring may have a substituent, in which case two adjacent substituents May be connected to each other to form a fused benzene ring. Xa-represents a counter anion. ]

Here, R ²⁰ and R ²¹ in the formula (VIII)
Is an alkyl group, the number of carbon atoms is usually 1 to 15, preferably 1 to 10, and when it is an alkenyl group or an alkynyl group, the number of carbon atoms is usually 2 to 15, preferably 2 to 10, and a phenyl group as those substituents including, from 1 to 15 carbon atoms, preferably 1 to 10 alkoxy group, a phenoxy group, hydroxy group, or a phenyl group, examples of the substituent in L ^1, directly Or an aromatic ring or a heterocyclic ring through an ether or thioether bond, an alkyl group, an amino group, or a halogen atom, and the like.
Examples thereof include an alkyl group, an alkoxy group, a nitro group, and a halogen atom. Of these, cyanine dyes having a heterocyclic ring on L ¹ directly or via an ether or thioether bond are preferred.

Further, if necessary, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzimidazole may be used as a polymerization accelerator in the photopolymerization initiation system used in the present invention.
Mercaptobenzoxazole, 3-mercapto-1,
By adding a hydrogen-donating compound such as 2,4-triazole, N-phenylglycine and a derivative thereof, and an alkyl N, N-dialkylbenzoate, the photopolymerization initiation ability can be further enhanced. Among them, particularly preferred are those having a mercapto group such as N-phenylglycine and derivatives thereof, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, 2-mercaptobenzoxazole, and 3-mercapto-1,2,4-triazole. Compounds and N, N-dialkyl benzoic acid alkyl esters.

The photopolymerizable composition of the present invention contains the ethylenically unsaturated compound of component (a) and the photopolymerization initiation system of component (b). The proportion in the whole product is preferably 20 to 80% by weight, in consideration of the content of other components described later, and 30 to 70% by weight.
It is particularly preferred that the amount is by weight.

The photopolymerizable composition of the present invention may contain, in addition to the above components, for example, (meth) acrylic acid, (meth) acrylic acid ester, (meth) acrylonitrile, (meth) acrylonitrile,
Acrylamide, maleic acid, styrene, vinyl acetate,
The above-mentioned component (A), wherein a homopolymer or a copolymer such as vinylidene chloride or maleimide, or an organic polymer substance such as polyamide, polyester, polyether, polyurethane, polyvinyl butyral, polyvinyl pyrrolidone, polyethylene oxide or acetylcellulose is used as a binder. Is preferably in the range of 10 to 500 parts by weight, particularly preferably 20 to 200 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound.

In addition, if necessary, various additives such as hydroquinone, p-methoxyphenol, 2,6-
Thermal polymerization inhibitor such as di-t-butyl-p-cresol
5 parts by weight or less of a coloring agent comprising an organic or inorganic dye or pigment
0 parts by weight or less, plasticizers such as dioctyl phthalate, didodecyl phthalate, tricresyl phosphate, dioctyl adipate, and triethylene glycol dicaprylate are 40 parts by weight or less, and sensitizing agents such as tertiary amines and thiols are 5 parts by weight. Hereinafter, dye precursors such as triarylmethane, bisarylmethane, xanthene compounds, fluorane compounds, thiazine compounds, and dye leuco bodies such as compounds having a lactone, lactam, sultone, or spiropyran structure as a partial skeleton thereof are 10 It may be added in each range of not more than parts by weight.

The use form of the photopolymerizable composition of the present invention as a light-sensitive material may be, for example, without a solvent or after dilution with an appropriate solvent, applied to the surface of a support, and dried. A form, or a form in which an overcoat layer for blocking oxygen is further provided thereon, a form in which droplets are dispersed in a heterogeneous medium and applied in multiple layers as a plurality of types of photosensitive materials, and a support in which microcapsules are included Although the form and the like coated on the photopolymerizable composition of the present invention can be adopted, the composition is coated on a support surface as a solution in which the composition is dissolved in an appropriate solvent,
The use form as a photopolymerizable lithographic printing plate in which a layer of the photopolymerizable composition of the present invention is formed on the surface of a support by heating and drying is suitable.

Here, the solvent is not particularly limited as long as it has a sufficient solubility for the components used and gives good coating properties. For example, methyl cellosolve,
Cellosolve solvents such as ethyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate , Propylene glycol solvents such as dipropylene glycol dimethyl ether, butyl acetate, amyl acetate, ethyl butyrate, butyl butyrate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate, ethyl acetoacetate, methyl lactate, ethyl lactate, Ester solvents such as methyl 3-methoxypropionate, heptanol Hexanol, diacetone alcohol, alcohol solvents such as furfuryl alcohol, cyclohexanone, ketone solvents such as methyl amyl ketone,
Highly polar solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like, or a mixed solvent thereof, and further a mixture thereof with an aromatic hydrocarbon may be used. The usage ratio of the solvent is usually in the range of about 1 to 20 times by weight based on the total amount of the photopolymerizable composition.

As the coating method, conventionally known methods such as spin coating, wire bar coating, dip coating, air knife coating, roll coating, blade coating, curtain coating and the like can be used. The coating amount varies depending on the application, but is usually 0.3 to 7 μm as a dry film thickness.
m, preferably 0.5-5 μm, particularly preferably 1-3
μm range. The drying temperature at that time is, for example, about 60 to 170 ° C, preferably 70 to 150 ° C.
The drying time is about 5 seconds to 10 minutes, preferably about 10 seconds to 5 minutes.

Incidentally, an oxygen barrier layer of polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, cellulose or the like is usually provided on the photopolymerizable composition layer in order to prevent a polymerization inhibition effect by oxygen. The photosensitive lithographic printing plate according to the present invention, depending on the characteristics of the photosensitive layer, a carbon arc lamp, a high-pressure mercury lamp, a xenon lamp, a metal halide lamp, an argon ion laser,
A lithographic printing plate can be obtained by exposing with an FD-YAG laser, a helium ion laser, a semiconductor laser, a YAG laser or the like, and developing with an aqueous alkaline developer or the like.

The developer used for developing the photoreceptor obtained by imagewise exposing the photopolymerizable lithographic printing plate of the present invention includes, for example,
Sodium silicate, potassium silicate, lithium silicate, ammonium silicate, sodium metasilicate, potassium metasilicate,
Sodium hydroxide, potassium hydroxide, lithium hydroxide,
Inorganic alkali salts such as sodium carbonate, sodium bicarbonate, potassium carbonate, dibasic sodium phosphate, tertiary sodium phosphate, dibasic ammonium phosphate, tertiary ammonium phosphate, sodium borate, potassium borate, ammonium borate, monomethylamine, dimethylamine, Trimethylamine,
Monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine,
Use is made of an alkali developer consisting of an aqueous solution of an organic amine compound such as monobutylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine and the like in a concentration of about 0.1 to 5% by weight. Of these, alkali metal silicates such as sodium silicate and potassium silicate which are inorganic alkali salts are preferable.

[0065]

EXAMPLES Examples 1 and 2 and Comparative Example 1 The following ethylenically unsaturated compounds as component (a) and radicals as polymerization initiators as component (b) were applied to the surface of an aluminum plate support prepared as follows. The coating thickness of the photopolymerizable composition coating solution comprising a generator, a sensitizer, a polymerization accelerator, a polymer binder of component (c), and other components, and a solvent was adjusted to 2.0 g / m ² and dried to form a photosensitive layer composed of the photopolymerizable composition, and further thereon a mixed aqueous solution of polyvinyl alcohol and polyvinyl pyrrolidone (polyvinyl alcohol: polyvinyl pyrrolidone = 70% by weight: 30% by weight) dry film thickness using a bar coater. the coating is 3 g / m ^2, by forming an oxygen barrier layer and dried, photosensitive lithographic printing plate of the photopolymerizable image forming material It was produced.

An aluminum plate having a support thickness of 0.24 mm (material: JIS-H
1050) was alkali-etched for 7 seconds in an aqueous solution of sodium hydroxide (3%) at 65 ° C.
The smut was removed by immersion in a sulfuric acid aqueous solution (10%) at 3 ° C. for 3 seconds. Then, using a sine wave AC power supply (50 Hz), electrolytic etching was performed in a 22 ° C. hydrochloric acid aqueous solution (1.5%) having a dissolved aluminum concentration of 1.1 g / L under the conditions shown in Table 1. Next, after performing desmut treatment in a 50 ° C. aqueous sodium hydroxide solution under the conditions shown in Table 1, alkali-insoluble smut was removed with a sulfuric acid aqueous solution (10%). Furthermore, using a DC power supply, the film weight was 20 mg / dm ² at a current density of 10 A / dm ² in a 30 ° C. sulfuric acid aqueous solution (20%).
Was anodized to obtain an aluminum support.

[0067]

[Table 1]

The irregular shape of the support surface was measured by AFM under the following measurement conditions. Needle correction processing and curved surface regression processing were performed on the measured data. Surface regression refers to performing a regression process by applying a quadratic surface. Further, in the needle correction processing, the surface is traced by a stylus having a finite size, so that a difference occurs between the surface unevenness shape of the sample surface and the measurement data. When a stylus traces a projection, the trajectory becomes wider than the actual surface, and when a valley bottom is traced, the width becomes narrower. Therefore, in order to remove the influence of the stylus tip radius, mechanical correction of the measurement data is performed. Table 2 below shows the results of obtaining the sharpness Sku of the surface height distribution, the degree of distortion Ssk of the surface height distribution, and the root mean square (RMS) deviation Sq of the surface height distribution from the data subjected to such processing. Was. The weight of the support before the anodization was measured with an electronic balance, and the amount of smut remaining on the surface was determined.

[0069]

[Table 2] <Measurement conditions> Measuring machine: SE-30K (manufactured by Kosaka Laboratories) Stylus tip radius: 2 μm Measuring force: 0.3 mN Measuring area: 200 μm × 200 μm Measuring pitch: 1 μm Vertical magnification: 5000 times Feeding speed: 0.1mm / s Number of measurements: 3

[Table 3]

FIG. 1 shows an electron micrograph of the surface of the support obtained in Example 1.

(A) Ethylenically unsaturated compound Mixture of methacryloyloxyethyl phosphate and bis (methacryloyloxyethyl) phosphate of the following A; 11 parts by weight of hexamethylene bis [tris (acryloyloxymethyl) ethyl urethane of the following B]; 22 parts by weight 2,2-bis (4-acryloyloxydiethyleneoxyphenyl) propane of the following C; 22 parts by weight

[0072]

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[0073] (b) a photopolymerization initiator system (b-1) a radical generator dicyclopentadienyl titanium bis [2,6-difluoro-3- (1-pyrrolyl) phenyl]; 5 parts by weight

(B-2) Sensitizer Compound of the following D; 0.5 parts by weight Compound of the following E; 0.5 parts by weight

[0075]

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(B-3) Polymerization accelerator 2-mercaptobenzothiazole; 5 parts by weight N-phenylglycine benzyl ester; 5 parts by weight

(C) Polymer binder Methyl methacrylate (80 mol%) / methacrylic acid (20 mol%) copolymer (weight average molecular weight: 50,000)
Reaction product obtained by reacting 3,4-epoxycyclohexylmethyl acrylate (53 oxidation, 50 mol% of carboxyl groups of methacrylic acid component reacted); 45 parts by weight

Other component pigment (P.B. 15: 6); 4 parts by weight dispersant ("Disperbyk 161" manufactured by BYK-Chemie);
2 parts by weight surfactant (“Emulgen 104P” manufactured by Kao Corporation); 2
Parts by weight surfactant ("S-381" manufactured by Asahi Glass Co., Ltd.); 0.3 parts by weight

Solvent propylene glycol monomethyl ether acetate; 600 parts by weight cyclohexanone; 545 parts by weight

Printing durability test The printing durability was measured by using an offset sheet-fed printing machine DAIYA-1F manufactured by Mitsubishi Heavy Industries, Ltd. as a printing machine, and Hi-Echo Red M manufactured by Toyo Ink Co., Ltd. as an ink. Printing pressure is 50 than usual
It increased by μm and accelerated. 10,000 after starting printing
The printed matter was extracted every 0 sheets, and the degree of solidness was visually evaluated. As a result, in Examples 1 and 2, solid reproducibility was good when the number of printed sheets was 80,000 or more. On the other hand, in Comparative Example 1, the solid reproducibility was good for up to 30,000 sheets, and the reproducibility was reduced more than that, and both Examples 1 and 2 were compared with Comparative Example 1. Excellent printing durability was exhibited. In addition, in the photosensitive lithographic printing plates prepared in Examples 1 and 2, good images were obtained by exposure and development.

[0081]

According to the present invention, a lithographic printing plate having excellent printing durability can be obtained even when a photosensitive layer comprising a photopolymerizable composition is provided by using a support having a specific surface shape of the present invention. It is suitable for exposure.

[Brief description of the drawings]

FIG. 1 is a diagram showing a distribution of surface height distribution due to a difference in sharpness Sku.

FIG. 2 is a diagram showing a distribution due to a difference in a value of a degree of distortion Ssk of a surface height distribution.

FIG. 3 is a view showing an electron micrograph of the surface of a support manufactured in Example 1 of the present invention.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AA12 AA14 AB03 AC08 AD01 BC13 BC42 CA00 DA20 DA36 FA10 FA17 2H084 AA00 AA30 AA36 BB02 BB13 CC05 2H096 AA06 BA05 BA06 CA01 CA03 EA04 EA23 GA08

Claims (11)

[Claims] 1. A printing plate for laser exposure wherein a photosensitive layer comprising (a) an ethylenically unsaturated compound and (b) a photopolymerizable composition containing a photopolymerization initiation system is formed on a support. And as a support, the sharpness Sku of the surface height distribution
Is 2.8 or more. 2. The printing plate for laser exposure according to claim 1, wherein a support having a degree of distortion Ssk of the surface height distribution of -0.45 or less is used as the support. 3. The printing plate for laser exposure according to claim 1, wherein a support having a root mean square (RMS) deviation Sq of 0.6 μm or more is used as the support. 4. A printing plate for laser exposure wherein a photosensitive layer comprising (a) an ethylenically unsaturated compound and (b) a photopolymerizable composition containing a photopolymerization initiation system is formed on a support. And as a support, the degree of distortion Ssk of its surface height distribution
A printing plate for laser exposure, wherein the printing plate has a value of -0.45 or less. 5. A printing plate for laser exposure wherein a photosensitive layer comprising (a) an ethylenically unsaturated compound and (b) a photopolymerizable composition containing a photopolymerization initiation system is formed on a support. And as a support, the root mean square (RMS) of its surface
A printing plate for laser exposure, wherein a printing plate having a deviation Sq of 0.6 μm or more is used. 6. The amount of smut remaining on the surface of the support,
The printing plate for laser exposure according to any one of claims 1 to 5, wherein the amount is 0.5 mg / dm2 or more. 7. The printing plate for laser exposure according to claim 1, wherein the photopolymerization initiation system is selected from a sensitizer and a radical generator. 8. The printing plate for laser exposure according to claim 1, wherein the support is produced by subjecting the support to a roughening treatment, a desmutting treatment, and an anodizing treatment in advance. 9. Desmut treatment conditions include a concentration of an aqueous alkali solution of 0.1 to 1.0% and a treatment temperature of 2%.
The printing plate for laser exposure according to claim 9, wherein the printing plate has a temperature of 0 to 60C and a processing time of 0.1 to 60 seconds. 10. The printing plate for laser exposure according to claim 9, wherein the conditions for the surface roughening treatment are a current density of 70 to 150 A / dm 2 and a treatment time of 6 to 14 seconds. 11. A method of making a printing plate for laser exposure, comprising exposing the printing plate according to claim 1 to a laser beam and then developing the printing plate with an aqueous developer.