JPH1039498A - Laser direct waterless photosensitive lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the direct waterless lithographic printing plate superior in sensitivity and image reproduction performance and ink receptivity by incorporating a linear organopolysiloxane and a reactive silane compound in a silicone rubber layer, and titanium monooxide and the like as a near infrared absorber in a photosensitive layer. SOLUTION: The laser direct waterless photosensitive lithographic printing plate has on a substrate at least the photosensitive layer the silicone rubber layer in this order. This silicon rubber layer contains the linear polysiloxane having hydroxyl groups on both ends and the reactive silane compound, and the photosensitive layer contains as the near infrared absorber, the titanium monooxide or at least one of (thio)pyriliumpoly-methinecyanine dyes, and this near infrared absorber is liable to cause abrasion due to heat occurring absorption of the laser beams.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser direct dampening solution-free photosensitive lithographic printing plate capable of forming a printing plate directly from digital image data using a near-infrared semiconductor laser. More specifically, the present invention relates to a laser direct dampening solution-free photosensitive lithographic printing plate comprising a substrate and a photosensitive layer and a silicone rubber layer applied in this order.

[0002]

2. Description of the Related Art In recent years, with the progress of digital image processing technology using a near-infrared semiconductor laser and a computer, a photosensitive lithographic plate has been directly used from digital image data formed on a computer without using a silver halide film for a printing plate. The printing plate is subjected to scanning exposure with a near-infrared semiconductor laser to insolubilize the exposed portion, and then an image is formed by an aqueous solution development process (wet development process) to make a plate, or the exposed portion is deteriorated, sublimated, melted and removed. Laser direct plate making technology, in which an image is formed by performing a dry development process to make a plate, has attracted attention. In particular, there is no need to consider the balance between water and printing ink, the printing operation is easy, there is little wasted paper at the beginning of printing, and the printing time is short. It is expected as a new printing system because it can produce printed matter.

[0003] Various attempts have been made with respect to a laser-direct fountain-free photosensitive lithographic printing plate used in the fountain-free digital printing system.
(A) A photosensitive layer and a silicone rubber layer are applied in this order on a support, and the silicone rubber layer is simultaneously melted in response to heat generated by ablation of an exposed portion of the photosensitive layer.
Removed by volatilization or combustion (Japanese Patent Laid-Open No. 7-1
64773, 6-186750, 6-19906
(B) 7-309001), (b) those in which the silicone rubber layer is degraded in response to the heat generated by ablation of the exposed portion of the photosensitive layer, the adhesiveness to the support is reduced, and then the silicone rubber layer is scraped off. Kaihei 6-55723, 6-5586
9, 6-92050) and (c) a method of forming an ink-adhesive toner image on a support provided with a silicone rubber layer by an electrophotographic method (Japanese Patent Application Laid-Open No. 51-66008). I have. Among these methods, the method (a) is considered to be more preferable because the image forming process is the simplest and the image with the normal image quality is easily obtained.

However, a photosensitive lithographic printing plate that does not require a laser direct dampening solution using the above-described ablation requires a large number of high-power semiconductor lasers because of insufficient sensitivity in practice. Of the printing ink is low, or the printing resistance is low, and the printing suitability is not yet sufficient.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive lithographic printing plate having high sensitivity, high printing resistance, and excellent laser ink directing properties, which is excellent in printing ink deposition. is there.

[0006]

The gist of the present invention is to solve the above-mentioned problems by providing a laser direct having a photosensitive layer containing at least a near-infrared absorbing agent and a silicone rubber layer on a substrate in this order. In a fountain solution unnecessary photosensitive lithographic printing plate, the silicone rubber layer contains a linear organopolysiloxane having a hydroxyl group at both ends and a reactive silane compound, and the photosensitive layer serves as a near-infrared absorber,
A laser direct dampening water-free photosensitive lithographic printing plate comprising at least one of titanium monoxide and (thio) pyrylium polymethine cyanine dye.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The substrate used in the present invention has the flexibility that can be set in a normal lithographic printing machine, and in addition to the function as a conventional substrate that can withstand the load applied during printing, the energy of the laser light absorbed by the photosensitive layer. Has the function of preventing the heat generated by the heat from being transmitted to the substrate and diffusing it, and enhancing the effect of ablation of the photosensitive layer and the silicone rubber layer, and serving as a central element of the configuration of the substrate (hereinafter simply referred to as the substrate). ) Can be used by itself, but for the purpose of adding various functions, the substrate and its photosensitive layer side surface (hereinafter, referred to as
It is preferable that the substrate (hereinafter, simply referred to as a composite substrate) be composed of an ink deposition layer provided on the front surface and / or a reinforcing layer provided on the back surface.

For the purpose of exhibiting the function of enhancing the effect of the ablation, it is preferable that the base material has a lower thermal conductivity because it has better heat insulating properties, that is, prevents the diffusion of heat. As the substrate used in the present invention, 300K (27
° C) is usually 0.1 W / mK or more.
2 W / mK or less, and 0.1 W / mK or more and 0.15 W / mK in order to further enhance the effect of preventing thermal diffusion.
The following are preferred. In addition, in order to suppress the thermal conductivity and increase the heat insulating effect, a material containing a gas such as air in the material of the base material, that is, a material having a low density is preferably used. In order to enhance the heat insulating effect, the density of the substrate is 0.5 g.
/ Cm ³ or more and 2.0 g / cm ³ or less, preferably 0.5
g / cm ³ or more and 1.5 g / cm ³ or less are more preferable.
When the thermal conductivity and density are significantly larger than the above range, the heat diffusion effect is weak and it is difficult to enhance the ablation effect, and when it is extremely small, the physical strength of the base material is reduced and it may be deformed during printing. .

Specific examples of the substrate include papers such as high-quality paper, resin-treated paper, and coated paper; wood board; synthetic paper; foamed polyethylene terephthalate sheet, expanded polypropylene sheet, expanded polyethylene sheet, expanded polystyrene sheet, and the like. Plastic sheets can be mentioned,
Coated paper, synthetic paper, art paper, photographic printing paper base paper, foamed polyethylene terephthalate sheet, foamed polypropylene sheet, foamed polyethylene sheet are preferred from the viewpoints of dimensional stability of the substrate, chemical resistance to solvents and the like contained in the ink, and the like. When there is a step of cleaning the printing plate with a cleaning agent containing water at the time of printing, a water-resistant material, that is, a foamed plastic or a water-resistant paper is preferable.

The thickness of the substrate is 10 μm to 3 mm, preferably 20 μm to 1 mm, more preferably 50 μm to 50 mm.
0 μm. The surface of the base material used in the present invention has an appropriate cushioning property to enhance the ink adhesion of the image portion of the photosensitive lithographic printing plate, has a high adhesion to the ink roller, and has a high ink transfer property. The composite substrate can be manufactured by providing an ink-filling layer that has the effect of increasing the

Specific examples of the ink inking layer include a polyethylene terephthalate sheet, a foamed polyethylene terephthalate sheet, a polypropylene sheet, a foamed polypropylene sheet, a polyethylene sheet, a foamed polyethylene sheet, and the like. It can be used by bonding to the material surface. Among them, the density is 0.1 g / cm ³ or more and 1.5 g / cm ³ for the purpose of enhancing the heat insulating effect together with the ink inking property.
A foamed polyethylene terephthalate sheet, a foamed polypropylene sheet, and a foamed polyethylene sheet of ³ or less are preferred. In addition, the durability of the printing plate is also improved by providing the ink deposition layer.

The thickness of the ink depositable layer is 1 μm to 1 m.
m, preferably 3 μm to 100 μm, more preferably 5 μm
μm to 75 μm. Further, a reinforcing layer is provided on the back surface of the base material used in the present invention for the purpose of enhancing the durability of the printing plate, and a composite substrate can be manufactured. Examples of the reinforcing sheet used for providing the reinforcing layer include: a sheet used for the base material; a sheet used for the ink deposition layer; a metal plate such as an aluminum plate, a copper plate, and an iron plate; an aluminum foil And the like can be appropriately selected from metal foils and the like. Among these, a polyethylene terephthalate sheet, a foamed polyethylene terephthalate sheet, and an aluminum plate are preferred. The thickness of the reinforcing layer is 10 μm to 3 mm, preferably 20 μm
１1 mm, more preferably 50 μm to 500 μm. Further, in the present invention, it is also possible to produce a composite substrate in which an ink deposition layer is provided on the surface of the substrate and a reinforcing layer is provided on the back surface.

As described above, the base material, the ink-adhesive layer, and the reinforcing layer are each mainly intended to have a heat insulating effect, ink-adhesiveness, and durability, and are therefore intended to improve the performance as a photosensitive printing plate. In addition, it is preferable to appropriately form a multilayer so as to make up for each other's shortage by making use of each characteristic.
For this reason, the same kind of material may be joined to a base material of a certain material as an ink-filling layer and / or a reinforcing layer, but in this case, each of the heat insulating effect, the ink-filling property, and the durability is satisfied. Therefore, a material of a grade suitable for the purpose may be appropriately selected. In the case of a composite substrate, it is of course important that the thermal conductivity of the entire composite substrate is low, but it is essential that the substrate itself be heat-insulating in order to at least secure a heat-insulating region. Therefore, it is preferable that the ink deposition layer provided on the surface is also heat-insulating.

As a specific example of a preferred composite substrate used in the present invention, for example, a 20 μm to 75 μm polyethylene terephthalate as an ink-adhesive layer is formed on the surface of art paper, high quality paper, resin processed paper or coated paper of 50 μm to 500 μm. Examples include a sheet, a foamed polyethylene terephthalate sheet, a polypropylene sheet, a foamed polypropylene sheet, a polyethylene sheet, and a laminated sheet of a foamed polyethylene sheet. Further, on the back surface of this composite substrate, as a reinforcing layer, the same type as the ink-injectable sheet or 100 μm to 500 μm
And three layers obtained by laminating an aluminum plate.

When laminating an ink-insulating sheet or a reinforcing sheet on the heat-insulating substrate, one or both of the two sheet surfaces to be laminated may be laminated, for example, as described in JP-A-2-25087. After applying an adhesive such as urethane resin to a thickness of 0.1 to 10 μm,
0 to 150 ° C, 0.1 to 50 kg / cm ² , 0.1 to 5
Lamination is performed under the condition of 0 m / s, and an ink-insulating layer or a reinforcing layer is formed on the heat-insulating substrate.

As described in detail above, in the present invention, the substrate means a layer that should be the main heat-insulating function in the substrate structure depending on its physical property value and layer thickness. The relationship between the layer configuration and the substrate can be modified to a degree that can be conceived by those skilled in the art. For example, the heat insulating function is almost equally borne between the base material and the ink depositing layer, or the base material itself is compounded to express the heat insulating function specified in the present invention in an integrated manner. It may be possible to intervene layers. The photosensitive layer used in the present invention efficiently absorbs near-infrared laser light, converts it into heat, causes ablation of the photosensitive layer and removes the photosensitive layer, and at the same time, responds to the heat generated by the silicone rubber layer. Contains a near-infrared absorbing agent having a function of inducing ablation, melting, volatilizing or burning, and / or removing the photosensitive layer by pressure during ablation.

The near-infrared absorbing agent used in the present invention has a property of easily causing ablation by heat generated by absorption of laser light. Specifically, it is selected from oily or aqueous titanium monoxide (TiO) and / or (thio) pyrylium polymethine cyanine dye. Preferred among the (thio) pyrylium polymethine cyanine dyes are the following general formulas (I) to (III):
A compound represented by

[0018]

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[In the formula, n and m each represent 0 or 1, k represents 0, 1 or 2, Y ⁻ represents an inorganic or organic anion, and R ^{1 to} R ⁶ represent a hydrogen atom, a carbon atom, respectively. An alkyl group having 1 to 15 carbon atoms which may be substituted
To 20 aromatic hydrocarbon groups, optionally substituted aromatic heterocyclic groups having 4 to 20 carbon atoms (optionally substituted aromatic hydrocarbon groups and optionally substituted aromatic heterocyclic groups The above substituent is an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms,
An alkoxycarbonyl group having 2 to 10 carbon atoms, a chlorine atom,
Selected from bromine atoms. ), An alkoxy group having 1 to 15 carbon atoms, an acyl group having 2 to 15 carbon atoms, and 2 to 10 carbon atoms
Represents an alkoxycarbonyl group, a chlorine atom or a bromine atom, and X ¹ and X ² each represent an oxygen atom or a sulfur atom. R ^{7 to} R ¹¹ each represent an optionally substituted alkyl group having 1 to 15 carbon atoms, and R ^{7 to} R ¹¹ may be bonded to each other to form a cyclic structure. And n and m each represent 0 or 1;
Represents 0, 1 or 2, and Y ^- represents

[0020]

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[0021] ^{I -, Br -, Cl -} , ClO 4 -, PF
₆ ^- or BF ₄ ^- shows ^{a, R 1, R 2, R} 3 and R ⁴ represents a phenyl group, compounds each represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms R ⁵ and R ⁶ are preferred. R ^{7 to} R ¹¹ are preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. In addition, R ^{7 to} R ¹¹ may be bonded to each other to form a cyclic structure.

[0022]

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## EQU1 ## At this time, preferred substituents R are a hydrogen atom, a halogen atom, a phenyl group, a diphenylamino group, a dialkylamino group or

[0024]

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## EQU1 ## Specific examples of preferred near-infrared absorbers used in the present invention are shown in Table 1, but are not limited to these examples. In Table 1, S-4
S-5 is an example of titanium monoxide, and S-6 to S-29 are examples of a (thio) pyrylium polymethine cyanine dye.

[0026]

[Table 1] Table 1 S-4 manufactured by Mitsubishi Materials Corporation titanium black 13
M, S-5 Titanium Black 12S manufactured by Mitsubishi Materials Corporation

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

[Table 5]

[0031]

[Table 6]

[0032]

[Table 7]

[0033]

[Table 8]

[0034]

[Table 9]

[0035]

[Table 10]

These near-infrared absorbers can be used alone or as a mixture of two or more, dissolved or dispersed in a photosensitive layer coating solution, and blended for use.

When the near-infrared absorbing agent is compounded, the compounding ratio in the photosensitive layer is 5 to 100% by weight, preferably 10 to 98% by weight, more preferably 20 to 100% by weight of the total solids in the photosensitive layer.
~ 95% by weight. If the compounding ratio of the near-infrared absorber is extremely low, the laser light cannot be sufficiently absorbed, and the ablation effect tends to be reduced. In this case, the thickness of the photosensitive layer is
0.05-100 μm, preferably 0.1-30 μm,
More preferably, it is 0.3 to 10 μm. Alternatively, a photosensitive layer comprising a near-infrared absorbing agent can be provided directly on the substrate by vapor deposition or sputtering of the near-infrared absorbing agent. In this case, the film thickness is 0.01 to 0.5 μm.
m, preferably 0.02 to 0.4 μm. In the photosensitive layer used in the present invention, in addition to the near infrared absorber,
An organic polymer substance can be added for the purpose of enhancing the coating properties, compatibility with the near-infrared absorbing agent, film strength in the photosensitive layer, and ablation effect.

Examples of the organic polymer include unsaturated acids such as (meth) acrylic acid and itaconic acid;
Alkyl acrylate, phenyl (meth) acrylate,
Copolymers of benzyl (meth) acrylate, styrene, α-methylstyrene and the like; alkyl methacrylate and alkyl acrylate polymers represented by polymethyl methacrylate; alkyl (meth) acrylate and acrylonitrile, vinyl chloride, Copolymers of vinylidene chloride, styrene, etc .; Copolymers of acrylonitrile with vinyl chloride or vinylidene chloride; Modified cellulose having a carboxyl group in the side chain; Polyethylene oxide; Polyvinylpyrrolidone; Phenol, o-, m-, p -Cresol, and / or
Or a novolak resin obtained by the condensation reaction of xylesol with aldehyde, acetone, etc .; polyether of epichlorohydrin with bisphenol A; soluble nylon; polyvinylidene chloride; chlorinated polyolefin; copolymer of vinyl chloride and vinyl acetate Vinyl acetate polymer; copolymer of acrylonitrile and styrene; copolymer of acrylonitrile, butadiene and styrene; polyvinyl alkyl ether; polyvinyl alkyl ketone; polystyrene; polyurethane; polyethylene terephthalate isophthalate; acetyl cellulose; Cellulose; acetylbutoxycellulose; celluloid; polyvinyl butyral and the like are used. The compounding ratio of the organic polymer substance in the photosensitive layer is from 0 to 95% by weight, preferably from 2 to 90% by weight, and more preferably from 5 to 80% by weight of the total solids of the photosensitive layer.

In the present invention, among the compounds that enhance the ablation effect, nitrocellulose described below is preferably used in the photosensitive layer. The nitrocellulose used in the present invention is provided on the photosensitive layer by decomposing by the heat generated by the absorption of the near-infrared laser light by the near-infrared absorber and efficiently generating a low-molecular gas. It has a function of accelerating the removal of the laser exposed portion of the silicone rubber layer.

The nitrocellulose is obtained by nitrating natural cellulose purified by a conventional method with a mixed acid.
It is obtained by introducing a part or all of a nitro group into three hydroxyl groups present in a glucopyranose ring which is a constitutional unit of cellulose. The nitrification degree of the nitrocellulose used in the present invention is 2 to 13, preferably 10 to 12.5, and more preferably 11 to 1.
2.5. Here, the degree of nitrification indicates the weight% of nitrogen atoms in nitrocellulose. If the degree of nitrification is extremely high,
Although the effect of accelerating ablation is enhanced, the stability at room temperature tends to decrease, and the nitrocellulose becomes explosive, which poses a danger in handling the nitrocellulose when producing a printing plate. If the nitrification degree is extremely low, the effect of accelerating ablation cannot be sufficiently obtained.

The nitrocellulose has a degree of polymerization of 20.
２００200, preferably 25-150. If the degree of polymerization is extremely high, the removal of the silicone rubber layer will be incomplete, and the ink adhesion of the laser-exposed portion (image portion) tends to be poor. If the degree of polymerization is extremely low, the coating properties of the photosensitive layer become poor and the silicone rubber layer tends to peel off. The compounding ratio of the nitrocellulose in the photosensitive layer is 5 to 80% by weight, preferably 10 to 70% by weight, more preferably 30 to 70% by weight, based on the total solid components of the photosensitive layer.

The photosensitive layer of the present invention may contain fine particles having a low thermal conductivity of 5 μm or less, such as calcium carbonate, magnesium carbonate, zirconium oxide, and kaolin, for the purpose of increasing the efficiency of ablation. In order to increase the film strength, fine particles of silicon oxide, titanium oxide, etc. can be applied in addition to the above fine particles. The compounding ratio of the fine particles is 0 to 50% by weight, preferably 0 to 25% by weight of the total solids of the photosensitive layer.

As the silicone rubber layer used in the present invention, a condensation-crosslinking type of curing the silicone rubber layer composition by a condensation reaction described below is used. The condensation-reaction type silicone rubber layer used in the present invention, compared with the addition-reaction type, has a loss due to a curing reaction with a trace amount of a phosphorus compound, an amine compound, an epoxy compound or the like existing in the air or in a coating solvent. Because there is little activity,
Excellent stability and productivity of silicone rubber layer.

The condensation-crosslinking type silicone rubber layer used in the present invention comprises, as essential components, a linear organopolysiloxane having hydroxyl groups at both ends and a reactive silane compound capable of crosslinking with the organopolysiloxane to form a silicone rubber layer. Including. The content of the linear organopolysiloxane having hydroxyl groups at both ends is preferably at least 80% by weight and less than 98% by weight based on the total solid content of the silicone rubber layer. Further, the content of the reactive silane compound is preferably 2% by weight or more and less than 80% by weight based on the total solid content of the silicone rubber layer. Examples of the linear organopolysiloxane having a hydroxyl group at both terminals used in the present invention include a linear organopolysiloxane represented by the following general formula (IV).

[0045]

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(Wherein, two R ¹² each independently represent a hydrogen atom, a methyl group, a phenyl group, or a vinyl group, and y is 1
The following integers are shown. Of the compounds represented by formula (IV), those in which R ¹² is a methyl group are preferred. The weight average molecular weight (hereinafter, abbreviated as Mw) of the organopolysiloxane is from 5,000 to
1,000,000, preferably 10,000 to
1,000,000. If the Mw is extremely low, the film strength of the silicone rubber layer will be reduced, and the printing resistance will be reduced. If the Mw is extremely high, the effect of removing the silicone rubber layer by ablation will be reduced, resulting in reduced sensitivity and reduced image reproducibility. Cheap.

The reactive silane compound used in the present invention reacts with the hydroxyl group of the linear organopolysiloxane having a hydroxyl group at both terminals to form a deacetic acid type, a deoxime type, a dealcohol type, a deamino type or A reactive silane compound having a molecular weight of 2,000 or less and having at least two or more functional groups capable of causing condensation and crosslinking, such as a dehydration type, is exemplified. Specific examples of the functional group include functional groups represented by the following formulas.

[0048]

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(In the formula, R ¹³ represents an alkyl group having 1 to 5 carbon atoms. When two R ¹³ are present in the same atomic group, they may be the same or different.) Group is an acyloxy group (—OCO
R ¹³ ) having three or more functional groups or an alkoxy group (—OR ¹³ ) having three or more functional groups,
It is preferable to form a silicone rubber layer in a short time after the drying treatment after the application. More preferably, the functional group is an acetoxy group and the number of functional groups is 3 or more, or the functional group is an alkoxy group and the number of functional groups is 6 or more.

Examples of the reactive silane compound include compounds represented by the following formulas (V) to (VIII). In the formula, Q represents a group selected from the functional groups which react with the hydroxyl groups of the above-mentioned linear organopolysiloxane having hydroxyl groups at both ends, and Q has at least two in one molecule.

[0051]

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(Wherein X is an alkyl group having 1 to 5 carbon atoms;
Phenyl group, vinyl _{group, H 2 N- (CH 2)} h -, CH
₂ ＣC (CH ₃ ) CO—, CH ₂ ＣＨCHCO—,

[0053]

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Wherein R ¹³ has 1 to 5 carbon atoms as described above.
R ¹⁴ represents an allyl group or — (CH ₂ )
_q -SiR ¹³ shows a _3-p Q p, R ¹⁵ is a hydrogen atom or an alkyl group, or a phenyl group having 1 to 5 carbon atoms, R ^13,
When a plurality of R ¹⁴ and R ¹⁵ are present in the same molecule, each of the plurality may be the same or different, and h, j and q each represent an integer of 1 to 5, and p and r
Each represents an integer of 1 to 3, s represents an integer of 2 to 4,
t and u each represent an integer of 0-5. The compounds represented by the following general formulas (IX) and (X) have 6 or more alkoxy groups, and the compounds represented by (XI) have 3 or more acyloxy groups. It is particularly advantageous as a reactive silane compound.

[0055]

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(In the general formula (IX), q represents an integer of 1 to 10, and R ¹⁶ represents an alkyl group having 1 to 5 carbon atoms.)

[0057]

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(In the general formula (X), q represents an integer of 1 to 10, and R ¹⁶ represents an alkyl group having 1 to 5 carbon atoms.)

[0059]

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(In the general formula (XI), T represents an alkyl group having 1 to 5 carbon atoms, a phenyl group or a vinyl group, and q represents 1 to 5)
An integer of 10, R ¹⁶ represents an alkyl group having 1 to 5 carbon atoms, and s represents 3 or 4. Table 2 shows more specific examples of the reactive silane compound used in the present invention, but the present invention is not limited to these examples.

[0061]

[Table 11]

[0062]

[Table 12]

[0063]

[Table 13]

The condensation-crosslinking type silicone rubber layer used in the present invention is composed of an organic carboxylic acid, a titanium compound, and a silane compound in order to increase the reaction efficiency of the condensation crosslinking reaction between the organopolysiloxane having hydroxyl groups at both ends and the reactive silane compound. A condensation catalyst such as an acid ester, a stannate, an aluminum organic ether, and a platinum-based catalyst is appropriately mixed, and a condensation reaction is performed to cure the mixture.

The compounding ratio of the organopolysiloxane having hydroxyl groups at both ends used in the present invention, the reactive silane compound and the condensation catalyst in the silicone rubber layer is such that the hydroxyl groups at both ends are based on the solid content of the entire silicone rubber layer. The organopolysiloxane has 80 to 98% by weight, preferably 85 to 98% by weight, and the reactive silane compound usually has
20% by weight, preferably 2 to 15% by weight, more preferably 2 to 7% by weight, and the condensation catalyst is 0.05 to 5% by weight, preferably 0.1 to 3% by weight, more preferably 0.1 to 3% by weight.
1% by weight.

If the ratio of the reactive silane compound or the condensation catalyst is extremely high, the ink repellency decreases, and it becomes difficult to remove the silicone rubber layer during ablation.
Sensitivity and image reproducibility decrease. On the other hand, when it is extremely low, the film strength of the silicone rubber layer is reduced, and the printing durability is reduced.

In order to increase the ink repellency of the silicone rubber layer, a polysiloxane other than the above-mentioned polyorganosiloxane having a hydroxyl group at both ends is used for the silicone rubber layer. 2 to 15% by weight, preferably 3 to 12% by weight based on the solid content
% By weight. As the polysiloxane, for example, Mw1 in which both terminals are trimethylsilylated
And a polydimethylsiloxane of 000 to 1,000,000.

These silicone rubber layers have excellent printing ink repellency and printing resistance, are easily removed by ablation, and have a function of providing high sensitivity and high image reproducibility. The silicone rubber layer has a scratch strength of 10 to 1
It is preferably 00 g. However, the scratch strength is
When a 0.2 mm sapphire needle is moved at a speed of 10 cm / min while applying a load on the printing plate, it represents the load (g) required to cause scratches. When the scratch strength is in the above range, printability such as repellency, printing resistance, sensitivity, and image reproducibility of the printing ink becomes good. The thickness of the silicone rubber layer used in the present invention is 0.1 to 10
μm, preferably 0.2 to 5 μm, more preferably 0.3 to 2 μm.

The above-described photosensitive layer composition and silicone rubber layer composition are dissolved in a suitable solvent to form a solution,
After applying this on the substrate by various coating devices such as a wire bar, a spinner and a roll coater on the support,
After drying, a photosensitive layer and a silicone rubber layer can be respectively formed. Examples of the coating solvent for the photosensitive layer include ketones such as methyl ethyl ketone and cyclohexanone; esters such as butyl acetate, amyl acetate and ethyl propionate; and hydrocarbons such as toluene, xylene, monochlorobenzene, carbon tetrachloride, trichloroethylene, and trichloroethane. And halogenated hydrocarbons, methylcellosolve, ethylcellosolve, ethers such as tetrahydrofuran, and further, propylene glycol monomethyl ether acetate, bentoxone, dimethylformamide and the like can be used in common use.As a coating solvent for the silicone rubber layer, n-hexane, cyclohexane,
Petroleum ether, aliphatic hydrocarbon solvent Exxon Chemical Co., Ltd .: Isopar E, H, G, and a mixed solvent of these solvents and the above-mentioned photosensitive layer coating solvent can be used.

Further, if necessary, the coated sample may be coated with a polypropylene sheet to protect the silicone rubber layer.
Various release plastic sheets such as polyethylene sheet, release treated polyethylene terephthalate, release treated paper,
A metal sheet of aluminum, iron, copper or the like can be laminated on the silicone rubber layer. The photosensitive sample provided with the photosensitive layer and the silicone rubber layer on the substrate is usually subjected to scanning exposure with a beam spot obtained by condensing a semiconductor laser light oscillating near infrared light of 680 to 1200 nm to a diameter of 5 to 30 μm. After the exposed portion is ablated, the exposed portion is used as a printing plate without post-processing.In order to remove fine particles of the photosensitive layer or silicone rubber layer generated by ablation attached to the exposed sample, silicone is used. A post-treatment of applying a physical stimulus such as a brush, a pad, an ultrasonic wave, or a spray may be performed while supplying an aqueous solution or an organic solvent containing a water-soluble organic solvent such as ethanol to the surface of the rubber layer as necessary.

As another method for removing fine particles generated by the ablation, a cover sheet having a surface having a higher adhesiveness to the fine particles than the silicone rubber layer may be used as the silicone rubber of the photosensitive sample used in the present invention. On the layer, before exposure, the silicone rubber surface and the adhesive cover sheet surface are laminated so that they match, and after exposure, the cover sheet is peeled off, a method of removing fine particles on the silicone rubber layer, or the exposed sample silicone. A method of laminating a cover sheet on a rubber layer in the same manner as described above and then peeling off the cover sheet is exemplified. Examples of the cover sheet include a base plate made of polyethylene terephthalate, polypropylene, polycarbonate, paper, and the like, on which an adhesive layer made of silicone rubber, ionomer, vinyl acetate, or the like is provided as necessary.

[0072]

EXAMPLES The present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. Examples 1 to 3 and Comparative Examples 1 to 3 The following photosensitive compositions were applied on the substrates shown in Table 3.

[Photosensitive layer composition] Near-infrared absorbing agent: Compound shown in Table 3 Compounding amount shown in Table 3 Organic polymer substance: Phenoxy resin (PKH-J, manufactured by Union Carbide Co., Ltd.) 20 weight Part Coating solvent: cyclohexanone 600 parts by weight Dichloroethane 100 parts by weight Ethanol 100 parts by weight After coating, the coating was dried at 85 ° C. for 3 minutes to provide a photosensitive layer having a dry film thickness of 1 μm. Subsequently, a silicone rubber layer having the following composition was applied on the photosensitive layer.

[Silicone rubber layer composition] Linear organopolysiloxane having hydroxyl groups at both ends: Compound of the following formula (y represents an integer of 1 or more)

[0075]

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Reactive silane compound: Compound shown in Table 3 Compounding amount shown in Table 3 Condensation catalyst: 0.8 parts by weight of dibutyltin dilaurate Coating solvent: 900 parts by weight of Isopar E (manufactured by Exxon Chemical Co.) After coating After drying at 100 ° C. for 4 minutes, a silicone rubber layer having a dry film thickness of 1 μm was provided to prepare a photosensitive sample.

The photosensitive sample was fixed on a rotating drum having a circumference of 20 cm so that the silicone rubber layer was on the outside, and the drum was rotated. Next, 830 is placed on the rotating sample.
nm, 30mW semiconductor laser light (Hitachi, Ltd.,
HL8325G) was condensed to a beam diameter of 15 μm, and scanning exposure was performed. Subsequently, the following items were evaluated. Table 3 shows the results.

[Sensitivity] The sample was scanned and exposed while rotating the rotating drum at various rotation speeds.
Observed with a microscope at × magnification, the maximum scanning speed (cm / sec) at which the silicone rubber layer at the laser-exposed area is removed,
The sensitivity was evaluated. The higher the scanning speed, the higher the sensitivity.

[Ink Ink Adhesion] A printing ink for a lithographic printing plate requiring no dampening solution (Aqualess Echo Red manufactured by Toyo Ink Co., Ltd.) ) Is kneaded with a rubber roller having a diameter of 7 cm, and then the ink-adhered roller is reciprocated on the sample in a state of being in contact with the silicone rubber layer of the sample to perform ink replenishment. The ink temporarily attached to the line portion is gradually removed by the reciprocation of the roller, and a sample from which the ink has been completely removed is used. A Mitsubishi Tokishi Art Paper (manufactured by Mitsubishi Paper Mills) is placed on the sample. the was laminated with 2kg / cm ^2, 60cm / min to overlap and the coated surface of the silicone rubber layer and the art paper samples were peeled off the art paper, which is formed on art paper thin line Than link image, we were evaluated for ink receptivity.

A: A continuous fine line image of 95% or more is reproduced on art paper. B: A fine line image portion exceeding 5% and not more than 20% is not transferred onto the art paper, and a fine line image that is discontinuous is reproduced. . C: Fine line image portions exceeding 20% and 40% or less were not transferred onto the art paper, and intermittent fine line images were reproduced. D: Fine line image portions exceeding 40% were not transferred onto the art paper, and intermittent fine line images were reproduced.

[0081]

[Table 14] * 1: The values in parentheses indicate the percentage by weight based on the total solid content of the silicone rubber layer. * 2: The values in parentheses indicate the percentage by weight based on the total solid content of the photosensitive layer.

The abbreviations ( K-1 and K-
2 ) represents the following substrate. K-1 75 μm polyethylene terephthalate K-2 A composite substrate obtained by laminating 35 μm foamed polyethylene terephthalate sheet having a density of 1.2 on both sides of 100 μm coated paper. In Table 3, the abbreviations ( Si1 , Si21 ) in the column of the reactive silane compound represent the compounds listed in Table 2, respectively. In Table 3, the abbreviations ( S-6 , S-11 ) in the column of the near-infrared absorber represent the compounds listed in Table 1, respectively. Abbreviations ( CS-1 , CS-2 , CS-
3 ) represents the following compound.

[0083]

Embedded image

Example 4 A photosensitive sample was prepared in the same manner as in Example 3 except that the photosensitive layer composition was changed to the following, and the evaluation was performed in the same manner. As a result, the sensitivity (58 m / s) and the ink inking property (A) were obtained.

[Photosensitive layer composition] Near infrared absorber: 70 parts by weight of titanium monoxide (manufactured by Mitsubishi Materials Corporation, titanium black 13M) Organic polymer substance: 30 parts by weight of styrene-acrylic acid copolymer (Johnson polymer Co., Ltd., John Griot J-555) Coating solvent: Cyclohexanone 800 parts by weight

Examples 5 to 19 and Comparative Examples 4 to 17 The following photosensitive layer compositions were applied to the substrates shown in Table 4 using a wire bar. [Photosensitive layer composition] Near-infrared absorber: 50 parts by weight of compounds shown in Table 4 Nitrocellulose: 50 parts by weight having a nitrification degree of 12 and an average degree of polymerization of 40 Coating solvent: 300 parts by weight of cyclohexanone N-methylpyrrolidone After coating at 600 parts by weight, the coating was dried at 85 ° C. for 3 minutes to provide a photosensitive layer having a dry film thickness of 1 μm. Subsequently, a silicone rubber layer composition having the following composition was applied onto the photosensitive layer. [Silicone rubber layer composition] Linear organopolysiloxane having hydroxyl groups at both ends: The following compound (y represents an integer of 1 or more)

[0087]

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Reactive silane compound: 7 parts by weight of compounds described in Table 4 Condensation catalyst: 0.8 part by weight of dibutyltin dilaurate Coating solvent: 900 parts by weight of Isopar E (manufactured by Exxon Chemical Co., Ltd.) After drying for a minute, a silicone rubber layer was provided so as to have a dry film thickness shown in Table 4 to prepare a photosensitive lithographic printing plate. The photosensitive lithographic printing plate is placed on a circumference 20c.
m and the silicone layer was fixed to the outside of the rotating drum, and the drum was rotated. Next, a 830 nm, 30 mW semiconductor laser (HL8325G, manufactured by Hitachi, Ltd.) was condensed to a beam diameter of 15 μm on the rotating printing plate, and scanning exposure was performed. Subsequently, the following items were evaluated. Table 4 shows the results.

[Practical sensitivity] The exposed photosensitive lithographic printing plate was mounted on a printing machine (DAIYA IF-2), and the surface of the printing plate was washed using a plate cleaner (PC-1) manufactured by Toray Industries, Inc. Printing was performed under the following conditions.・ Printing speed: 6000 sheets / h ・ Ink: New ALPO-G indigo L (manufactured by T & K Toka) ・ Printing paper: OK special art (manufactured by Oji Paper) ・ Nip width during printing: between plate and blanket 8 to 8.8 mm Between plate and inking roller 4.6 to 5.5 mm ・ Temperature: K1 roll 35 ° C. Room temperature 25 ° C. ・ Number of prints: 10,000 sheets The ink image of the obtained printed matter is observed with a microscope of 100 ×, The sensitivity was evaluated based on the maximum scanning speed (cm / s) of the laser when an ink image corresponding to the laser-exposed portion was obtained. The higher the scanning speed, the higher the sensitivity.

[Background Smear] The amount of ink adhering to the non-image area of the printed matter (background smear) was measured using a MABETH densitometer (TR927 SPI filter for cyan) and evaluated. A: The optical density of the non-image area was less than 0.01. B: The optical density of the non-image area was 0.01 or more and less than 0.04. C: The optical density of the non-image area was 0.04 or more and less than 0.1. D: The optical density of the non-image area was 0.1 or more and less than 0.3. E: The optical density of the non-image area was 0.3 or more. F: The formation of the printed image was insufficient and evaluation was not possible.

[Silicone Peeling] The silicone rubber layer in the non-image area of the printing plate after printing was visually observed, and the degree of peeling of the silicone rubber layer from the photosensitive layer was evaluated. A: No peeling of the silicone rubber layer was observed. B: Less than 10% of the silicone rubber layer in the non-image area was peeled off. C: 10% or more and 20 of the silicone rubber layer in the non-image area
Less than peeled. D: 20% or more of the silicone rubber layer in the non-image area was peeled off.

[0092]

[Table 15]

[0093]

[Table 16]

In Table 4, abbreviations ( K-1 , K-
2 , K-3 , K-4 , K-5 ) represent the same as described above. In Table 4, abbreviations (Si
1, Si4, Si9, Si11, Si21, Si22,
Si23) represents the compounds described in Table 2. In Table 4, the abbreviations (S-4, S-5, S
-6, S-14, S-18, S-19 and S-37) represent the compounds described in Table 1, respectively. The abbreviation (CS
-1, CS-2) represent the same as described above, and the abbreviation (CS
-3, CS-4, CS-5, CS-6, CS-7, CS
-8) represents the following.

[0095]

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[0096]

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Example 20 In Example 5, nitrocellulose was not added to the photosensitive composition, and phenoxy resin 50 was used as an organic polymer substance.
A light-sensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 5 except that a weight part (PKH-J, manufactured by Union Carbide Co., Ltd.) was blended. As a result, the practical sensitivity (40 cm
/ S), background stain (A), and silicone peeling (A) were obtained.

Example 21 In Example 5, a semiconductor laser (manufactured by Santa Fe Laser Co., model My) having a wavelength of 1060 nm was used as a laser beam, using S-19 as a near-infrared absorber.
A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 5, except that a laser beam of 50 mW from LS-500) was used. As a result, the practical sensitivity (60 cm /
s), background stain (A), and silicone release (A) were obtained.

Example 22 In Example 5, a primer D (manufactured by Dow Corning Toray Silicone Co., Ltd.) having a dry film thickness of 0.5 μm was formed on the photosensitive layer.
m and dried at 80 ° C. for 1 minute. On top of that, except that the reactive silane compound was changed to Si21 ,
Similarly, a silicone rubber layer was provided, and a photosensitive lithographic printing plate was prepared and evaluated. As a result, the practical sensitivity (75 cm
/ S), background stain (A), and silicone peeling (A) were obtained.

Reference Example 1 In Example 5, the silicone rubber layer was replaced with an addition-crosslinkable silicone rubber: KS3600 (100
(Parts by weight), and a photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 5. As a result, formation of a printed image was insufficient, and practical sensitivity and background contamination could not be evaluated. The silicone release was (D).

Comparative Example 12 A photosensitive lithographic printing plate was prepared and evaluated in the same manner as in Example 5, except that the silicone rubber layer was not provided. As a result, formation of a printed image was insufficient, and practical sensitivity and background contamination could not be evaluated.
The silicone release was (D).

[0102]

According to the present invention, it is possible to provide a photosensitive lithographic printing plate which is excellent in sensitivity, image reproducibility and ink depositing property, and does not require a fountain solution.

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[Procedure amendment]

[Submission date] August 20, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Change

[Correction contents]

The abbreviations (K-1, K-
2) shows the same as above. The abbreviations (K-3, K
-4, K-5) indicate the following substrates. K-3: A 20% solution of cyclohexanone of phenoxy resin (PKH-J) manufactured by Union Carbide Co., Ltd. on an aluminum sheet having a thickness of 0.3 mm was dried with a wire bar using a wire bar.
A phenoxy resin-coated aluminum sheet substrate obtained by coating to a thickness of 0 μm and drying at 100 ° C. for 4 minutes. K-4: A composite substrate obtained by laminating a foamed polypropylene sheet (GWG manufactured by Oji Yuka Synthetic Paper) having a thickness of 140 μm on an aluminum sheet having a thickness of 0.2 mm. K-5: 75 μm thick polyethylene terephthalate sheet. In Table 4, abbreviations (Si1, S
i4, Si9, Si21, Si22, and Si23) represent the compounds described in Table 2, respectively. In Table 4, abbreviations (S-4, S-5, S-6, S-14,
S-18 and S-19) represent the compounds described in Table 1, respectively. The abbreviations (CS-1, CS-2) represent the same as described above, and the abbreviations (CS-4, CS-5, CS-6,
CS-7, CS-8) represent the following.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G03F 7/075 501 G03F 7/075 501 521 521

Claims (7)

[Claims] 1. A laser-direct fountain-free photosensitive lithographic printing plate having a photosensitive layer containing at least a near-infrared absorber and a silicone rubber layer in this order on the substrate, wherein the silicone rubber layer is A linear organopolysiloxane having hydroxyl groups at both ends and a reactive silane compound, and wherein the photosensitive layer is a near-infrared absorber;
A photosensitive lithographic printing plate requiring no laser direct dampening solution, comprising at least one of titanium monoxide and (thio) pyrylium polymethine cyanine dye. 2. The method according to claim 1, wherein the silicone rubber layer comprises a linear organopolysiloxane having a hydroxyl group at both ends of not less than 80% by weight and less than 98% by weight based on the total solid content of the silicone rubber layer. 2% by weight or more 2
2. The photosensitive lithographic printing plate according to claim 1, further comprising less than 0% by weight of a reactive silane compound. 3. The laser direct according to claim 1, wherein the near-infrared absorbing agent is at least one kind of a (thio) pyrylium polymethine cyanine dye represented by the following general formulas (I) to (III). A photosensitive lithographic printing plate that does not require dampening water. Embedded image [Wherein, n and m each represent 0 or 1, k is 0,
1 or indicates 2, Y ^- represents an anion of an inorganic or organic, R ¹ to R ⁶ are each a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, optionally substituted aromatic having from 6 to 20 carbon atoms Hydrocarbon group, optionally substituted carbon number 4-20
An aromatic heterocyclic group (optionally substituted aromatic hydrocarbon group and a substituent on the optionally substituted aromatic heterocyclic group may be an alkyl group having 1 to 10 carbon atoms, An alkoxy group, an acyl group having 2 to 10 carbon atoms,
It is selected from 10 alkoxycarbonyl groups, chlorine atoms and bromine atoms. ), An alkoxy group having 1 to 15 carbon atoms,
X ¹ represents an acyl group having 2 to 15 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, a chlorine atom or a bromine atom;
And X ² each represent an oxygen atom or a sulfur atom. R ⁷
To R ¹¹ each have 1 to 15 carbon atoms which may be substituted;
And R ^{7 to} R ¹¹ may be bonded to each other to form a cyclic structure. ] 4. The near-infrared absorbing agent is at least one of the (thio) pyrylium polymethine cyanine dyes represented by the general formulas (I) to (III), wherein Y ⁻ is ] ^{I -, Br -, Cl -} , ClO 4 -, PF 6 - or BF
₄ ^- and, R ^1, R ^2, R ³ and R ⁴ is phenyl, laser according to R ⁵ and R ⁶ according to claim 3 are each hydrogen atom or an alkyl group having 1 to 5 carbon atoms directly A photosensitive lithographic printing plate that does not require dampening water. 5. The method of claim 1, wherein the reactive silane compound has three or more acyloxy groups or six or more alkoxy groups in one molecule. Sexographic printing plate. 6. The photosensitive lithographic printing method according to claim 5, wherein the reactive silane compound is selected from compounds represented by the following general formulas (IX) to (XI). Edition. Embedded image (Wherein, R ¹⁶ represents an alkyl group having 1 to 5 carbon atoms, q represents an integer of 1 to 10. Further, s represents 3 or 4, and T represents
Represents an alkyl group having 1 to 5 carbon atoms, a phenyl group, or a vinyl group. ) 7. The photosensitive lithographic printing plate according to claim 1, further comprising nitrocellulose in the photosensitive layer.