JP2000194125A - Production of lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a producing method of a lithographic printing plate which enables laser recording and which satisfies requirements for the removing performance of an ink-repelling layer in the exposed region to laser light and for the printing performance. SOLUTION: The producing method of a lithographic printing plate features that the following processes are sequentially carried out. They are a process to expose a lithographic printing original plate 11 having a photothermal conversion layer and an ink-repelling layer laminated in this order on a support to laser light, a process to rub the surface of the ink-repelling layer with a rubbing member 1a disposed in a developing means 13 without the presence of a liquid, a process to rub the surface of the ink-repelling layer with a rubbing member 1b disposed in a cleaning means 14 in the presence of a detergent liquid containing a surfactant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a lithographic printing plate by heat mode recording using a laser beam.

[0002]

2. Description of the Related Art With the recent advance in computer technology, in the printing field, a plate making process, which is a pre-printing process conventionally performed manually, has been digitized, and a printed image has been digitized. A technology (computer-to-plate technology) for directly forming a printing plate material from this digital data without using a lith film has been developed. Above all, waterless lithographic printing plates that do not use dampening water for low-volume printing applications do not require proficiency in printing work because they do not use dampening water. It has advantageous features such as less.

An example of such a waterless lithographic plate which can be formed by laser writing is disclosed in Japanese Patent Publication No. 42187/1972.
No. 9 has the oldest disclosure. It describes that the ink repellent silicone layer is partially removed by laser irradiation to make the ink adherent, and printing is performed without water. However, the silicone in the laser-irradiated part scatters over the entire plate surface, causing problems during printing, and the laser irradiation alone does not sufficiently remove the silicone layer, so the area of the ink-attached part increases as printing progresses (dot gain). There was a problem.

Further, Japanese Patent Application Laid-Open No. 50-158405 discloses that a printing original plate having a silicone rubber surface layer is irradiated with a YAG laser, which is an infrared laser, to emit a solvent (naphtha).
A method of forming a waterless lithographic plate by removing a laser irradiated portion by a treatment is disclosed. Also, EP-05730
91B has a YA on a plate material having a silicone rubber surface layer.
There is disclosed a method of forming a waterless plate by irradiating with a G laser and rubbing under dry conditions without solvent or by rubbing while applying a solvent that does not swell the silicone rubber. However, when the physical removal by rubbing the silicone rubber in the laser exposed part was performed under dry conditions, the silicone rubber residue removed from the exposed part was removed from the silicone rubber layer or the silicone rubber layer in the non-image part. It easily adheres to the image area, and the silicone rubber layer in the non-image area is easily scratched. When printing is performed using the waterless lithographic plate formed by this method, the non-image area is scratched and stained, and the image area is damaged. There is a problem that inconveniences such as slippage occur.

On the other hand, when using a liquid to remove the silicone rubber at the portion exposed to the laser by rubbing,
Compared to the case where no liquid is used, the adhesion of the silicone rubber residue to the plate surface is improved, but the frictional resistance between the rubbing member and the surface of the silicone rubber layer is reduced. Efficiency becomes worse. For this reason, it is necessary to strengthen the rubbing conditions such as the pressure and the number of times. In particular, when a liquid that swells silicone rubber (for example, a liquid containing a hydrocarbon-based solvent such as naphtha as a main component) is used as the liquid, the film strength of the silicone rubber decreases, and thus the silicone in the non-image area is reduced. There was a problem that the rubber layer was easily damaged.

As described above, several methods of directly forming a lithographic printing plate using a laser have been conventionally proposed. However, the removal performance (developability) and printing performance of the ink repellent layer at the portion exposed to the laser are improved. At present, they are not satisfied.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention is capable of laser recording,
An object of the present invention is to provide a method of manufacturing a lithographic printing plate that satisfies the performance of removing the ink-repellent layer in the exposed portion and the printing performance. Specifically, the present invention eliminates the contamination of the non-image area, which is a problem during printing, when removing the ink repellent layer in the exposed area to form an image, and further causes the image area to pass through. An object of the present invention is to provide a method for producing a lithographic printing plate in which a substance does not remain on the plate surface.

[0008]

Means for solving the above problems are as follows. That is, <1> a step of subjecting a lithographic printing plate precursor obtained by laminating a light-heat conversion layer and an ink repellent layer in this order on a support to laser exposure, and a developing means in the absence of a liquid. A developing step of rubbing the surface of the ink repellent layer with a rubbing member, and a cleaning step of rubbing the surface of the ink repellent layer with a rubbing member provided in a cleaning means in the presence of a cleaning solution containing a surfactant. This is a method for producing a lithographic printing plate, which is performed sequentially.

In the present specification, a lithographic printing plate precursor refers to a plate material in which an image forming pattern of an ink receiving portion and a non-ink receiving portion is not formed, and a lithographic printing plate refers to an ink receiving portion. And an image pattern of a non-ink receiving portion is formed,
This shows a plate material ready for printing.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the method for producing a lithographic printing plate according to the invention, a step of exposing the lithographic printing plate precursor to laser light and a step of rubbing the surface of the ink repellent layer with a rubbing member provided in a developing means (hereinafter, referred to as a “development step”) ) And a step of rubbing the surface of the ink repellent layer with a rubbing member provided in the cleaning means (hereinafter, referred to as a “cleaning step”). The lithographic printing plate precursor used in the invention has a light-to-heat conversion layer and an ink repellent layer sequentially provided on a support. Here, since a layer made of silicone rubber is preferably used as the ink repellent layer, a silicone rubber layer will be described as a typical example of the ink repellent layer.

[Laser Exposure Step] In the present invention, when the lithographic printing plate precursor is irradiated with laser light, the laser energy is absorbed by the light-to-heat conversion layer, and the light-to-heat conversion layer for converting light into heat is simultaneously irradiated with the laser. The temperature rises rapidly, and due to chemical reaction or physical change such as combustion, melting, decomposition, vaporization, explosion, etc. of part or all of the light-to-heat conversion layer, as a result, it adheres at any part between the support and the silicone rubber layer Is reduced. Since such a decrease in adhesion occurs only in the area irradiated with the laser, the silicone rubber layer in the corresponding portion can be selectively removed.

In the present invention, a laser beam is used to expose the lithographic printing plate precursor. The laser to be used is not particularly limited as long as it provides an exposure amount that causes a sufficient decrease in adhesion to remove the silicone rubber layer. For example, a gas laser such as an Ar laser or a carbon dioxide laser, a solid-state laser such as a YAG laser, a semiconductor laser, or the like can be used. Usually, a laser having a power of 100 mW class or more is required. Semiconductor lasers and semiconductor-pumped solid-state lasers (such as YAG lasers) are preferably used in terms of practicality such as maintainability and price. The recording wavelength of these lasers is in the infrared wavelength range, and usually uses an oscillation wavelength of 800 to 1100 nm. Laser beam diameter is usually 5-200 μm
(1 / e ² ).

The laser irradiation is preferably carried out from the side of the silicone rubber layer of the lithographic printing plate precursor. However, when the support is transparent to the irradiated laser beam, the irradiation can be carried out from the side of the support. Also, Japanese Patent Application Laid-Open No. 6-18675
Exposure can also be performed using an imaging apparatus described in Japanese Patent Publication No. In the present invention, a planographic printing plate is manufactured by exposing the ink receptive portion by selectively removing the ink repellent material in the laser exposed portion by utilizing the decrease in the adhesion of the laser exposed portion.

[Developing Step / Cleaning Step] In the present invention, the silicone rubber layer is removed from the laser-exposed portion by rubbing the surface of the silicone rubber layer with a rubbing member provided in a developing means in the absence of a liquid. A developing step of rubbing, followed by a cleaning step of rubbing the surface of the lithographic printing plate with a rubbing member provided in a cleaning means in the presence of a liquid having a high affinity (good wettability) for the surface of the silicone rubber layer. , Consisting of Removal of the silicone rubber layer in the laser-exposed area in the absence of liquid is more efficient in the absence of liquid than in the presence of liquid, because the frictional resistance between the silicone rubber layer and the rubbing member is greater, and the removal efficiency is higher. Good. However, when the surface of the silicone rubber layer is rubbed in the absence of a liquid, the residue of the silicone rubber removed from the silicone rubber layer in the laser-exposed portion may become non-image portions of the silicone rubber layer or the silicone rubber layer. It easily adheres to the removed image area.

As described above, in order to remove the silicone rubber residue re-adhered to the plate surface from the plate surface by washing, the silicone rubber residue is removed from the silicone rubber layer in the presence of a liquid having a high affinity (good wettability). It is effective to scrape off and wash away from the plate surface. However, when a liquid that easily swells the silicone rubber layer or a liquid that easily penetrates the silicone rubber layer is used as such a liquid, in order to reduce the film strength of the silicone rubber layer and the adhesion to the lower layer, The silicone rubber layer in the non-image area is easily damaged. For this reason, as the liquid used in the rubbing treatment, it is suitable to use a liquid that hardly swells the silicone rubber layer and hardly penetrates the silicone rubber layer. A liquid containing an activator and containing water as a main component is used.

As described above, in the present invention, the efficiency of removing the silicone rubber layer in the laser-exposed portion and the prevention of the adhesion of the residue of the silicone rubber removed from the silicone rubber layer in the laser-exposed portion to the plate surface. First, a rubbing treatment is carried out in the absence of a liquid by a rubbing member provided in the developing means to efficiently remove the silicone rubber layer from the laser-exposed portion. Next, a rubbing process is performed by a rubbing member provided in the cleaning unit in the presence of a cleaning solution containing a surfactant, and a residue of the silicone rubber adhered to the plate surface in the processing by the developing unit is washed and removed. And

(Developing Means / Cleaning Means) The developing means and cleaning means in the present invention are not particularly limited as long as the object of the present invention can be achieved. Is preferably used. The automatic processor includes at least a developing unit and a cleaning unit each provided with a rubbing member, and the lithographic printing plate precursor after laser exposure is transported into the automatic processor while the developing unit and the cleaning unit. Are sequentially rubbed.

FIG. 1 is a schematic view showing an example of an automatic processor suitable for removing the silicone rubber layer preferably used in the present invention. The automatic processing machine shown in FIG. 1 is a system in which the cleaning liquid used in the rubbing process in the cleaning means 14 is sent to the spray pipe 5 by the circulation pump 8, showered, and supplied to the rubbing member and the plate surface. The rubbing members provided in the means 13 and the cleaning means 14 are the rotating brush rollers 1a and 1b. In the present invention, the lithographic printing plate after the processing in the developing means and the cleaning means can be arbitrarily washed with water and dried.

FIG. 2 is a schematic view showing another example of an automatic processor suitable for removing the silicone rubber layer preferably used in the present invention. The automatic processing machine shown in FIG. 2 is provided with a rotating blade rubber roller 15 as a rubbing member in the developing means 13, and two rubbing members in the cleaning means 14 for effectively cleaning and removing the silicone rubber residue. Rotary brush rollers 1c and 1d are provided. This automatic processing machine uses two circulation pumps 8 and 8 ′ to spray cleaning liquid used for rubbing processing in the cleaning means 14 with spray pipes 5 and 5 ′, respectively.
To the rubbing member and the plate surface after showering.

(Rubbing Member) The rubbing member used in the present invention is preferably a rotating roller. For example, a brush, sponge, rubber blade, cotton pad, Molton,
A roller-shaped member having a structure in which a material such as a synthetic fiber woven fabric or a foamed resin is disposed can be preferably used. These are considered in consideration of the removal performance of the silicone rubber layer in the portion exposed to the laser and the difficulty of scratching the surface of the silicone rubber layer in the unexposed portion, and further, the rigidity of the support of the lithographic printing plate precursor, It can be selected as appropriate. Among them, a brush roller is preferable.
No., JP-A-3-100554, Japanese Utility Model Application Laid-Open No. 62-1672.
It is preferable to use a brush roll in which a metal or plastic channel material in which brush materials are implanted in a row and radially wound around a plastic or metal roll serving as a core without gaps as described in Japanese Patent Publication No. 53, etc. Can be.

Examples of the brush material of the brush roller include plastic fibers (for example, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6.6 and nylon 6.10, polyacrylonitrile, poly (meta). ) Polyacrylic synthetic fibers such as alkyl acrylate and polyolefinic synthetic fibers such as polypropylene and polystyrene)
Is mentioned. The hair diameter of the plastic fiber is 5
The length of the hair is preferably 7 to 2 μm.
5 mm is preferred. Further, the outer diameter of the brush roller is preferably 40 to 150 mm, and the peripheral speed of the tip of the brush rubbing the surface of the silicone rubber layer is 0.3 to 4 m / m.
Seconds are preferred.

Also, a blade roller is preferably used, and a blade roller in which a rubber blade is spirally arranged on the surface of a roller body member can be preferably used. As the rubber blade material of the blade roller, for example, polyurethane, natural rubber, synthetic natural rubber,
Butadiene rubber, styrene-butadiene rubber, butadiene-acrylonitrile rubber, chloroprene rubber, polysulfide synthetic rubber, chlorosulfonated polyethylene, chlorinated polyethylene, ethylene-propylene rubber, silicon rubber, fluorine rubber, acrylic rubber, nitrile-isoprene rubber , Ethylene-vinyl acetate rubber, epichlorohydrin rubber and the like. The thickness of the blade is 0.1 to
5 mm is preferable, and the width of the blade is 1 to 20 mm.
Is preferred. The rubber hardness is preferably from 10 to 100 degrees. Further, the outer diameter of the blade roller is 30 to 1
The peripheral speed of the tip of the blade rubbing the surface of the silicone rubber layer is preferably 0.3 to 4 m / sec.

A plurality of rotary roller-like rubbing members preferably provided in each of the developing means and the cleaning means may be arranged in each part, or the same or different rubbing members may be used. Furthermore, the rotation direction of the rotating roller-like rubbing member preferably used in the present invention may be the same direction or the opposite direction to the transport direction of the lithographic printing plate precursor, but is the same in consideration of the transportability of the lithographic printing plate precursor. The direction is preferred. Further, in order to improve the performance of removing the silicone rubber layer from the laser-exposed portion, the rotating roller-shaped rubbing member can be swung in the rotation axis direction of the roller.

(Surfactant) As the surfactant contained in the washing solution used in the washing step, conventionally known surfactants can be used, but troubles due to the generation of bubbles in the automatic processing machine are taken into consideration. Then, it is preferable to use a nonionic surfactant. Nonionic surfactants preferably used in the present invention include, for example,
Polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, oil and fat Ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, etc., polyhydric alcohol-type glycerol fatty acid ester, pentaerythritol fatty acid ester , Sorbitol and sorbitan fatty acid esters, sucrose fatty acid esters, polyvalent alcohols Alkyl ethers of the call, fatty acid amides of alkanolamines.

These nonionic surfactants may be used alone or in combination of two or more. In the present invention, sorbitol and / or sorbitan fatty acid ester ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide) block copolymer, polyhydric alcohol Fatty acid esters are more preferably used.

From the viewpoint of stable solubility or turbidity in water and affinity for the silicone rubber layer,
Nonionic surfactants used in the present invention include H
LB (Hydrophile-Lipophile)
(Balance) value is preferably 5 to 13. Further, the surfactant concentration of the cleaning liquid containing the surfactant is preferably 0.01 to 5% by weight. Further, as long as the silicone rubber layer in the non-image area is not damaged by the swelling of the silicone rubber layer and / or the permeation of the liquid into the silicone rubber layer, the affinity (wetting property) to the silicone rubber layer is improved. For the purpose, the cleaning liquid (aqueous solution) containing a surfactant may contain another solvent. Further, known antifoaming agents and preservatives can be added.

Here, the affinity of the liquid for the silicone rubber layer can be estimated as the contact angle of the liquid to the silicone rubber layer (contact angle by the air droplet method). The contact angle with the silicone rubber layer is preferably 90 ° or less. The temperature of the cleaning solution containing the surfactant is not particularly limited, but is preferably from 10 to 50 ° C.

Hereinafter, the planographic printing plate precursor used in the method for producing a planographic printing plate of the present invention will be described in detail. The lithographic printing plate precursor is obtained by laminating a light-to-heat conversion layer and an ink repellent layer in this order on a support, and further laminating other layers as necessary.

[Support] As the support, there may be used any known metal, plastic film, paper, and composite supports thereof which are commonly used for offset printing. Naturally, it is necessary to satisfy physical properties such as mechanical strength and elongation resistance required under the printing conditions used. The support may be subjected to a surface treatment such as a corona treatment in order to improve the adhesion to the light-to-heat conversion layer formed on the support, improve the printing characteristics, or increase the sensitivity. Specific examples of the support include, for example, a metal support such as aluminum, a plastic support such as polyethylene terephthalate, polyethylene naphthalate, and polycarbonate; and a composite sheet in which paper or paper is laminated with a plastic film such as polyethylene or polypropylene. And the like. The thickness of the support is about 25 μm to 3 mm, preferably 75 to 500 μm, but the optimum thickness varies depending on the type of support used and printing conditions. Generally, 100 to 300 μm is most preferable.

[Light-to-heat conversion layer] The light-to-heat conversion layer is formed of a substance that converts laser light used for writing into heat (hereinafter, referred to as heat).
It is referred to as "light-to-heat conversion material". ), And by exposure,
A layer having a function of reducing the adhesive strength between adjacent layers. Known light-to-heat conversion layers having these functions can be used as the light-to-heat conversion layer.

(Light-to-heat conversion material) As the light-to-heat conversion material, conventionally, when a laser light source is an infrared laser,
Infrared absorbing pigment, infrared absorbing pigment, infrared absorbing metal,
It is known that various organic and inorganic materials that absorb light having a wavelength used for a writing laser, such as an infrared absorbing metal oxide, can be used. These materials are used in the form of a single film or a mixed film with other components such as a binder and an additive. In the case of the single film, aluminum, titanium, tellurium, chromium, tin, indium, bismuth, zinc, lead and other metals and alloys and metal oxides, metal carbides, metal nitrides, metal borides, metal halides, An organic dye or the like can be formed on the support by a vapor deposition method, a sputtering method, or the like. In the case of the mixed film, the photothermal conversion material can be formed by dissolving or dispersing the photothermal conversion material together with other components by a coating method.

The photothermal conversion material used in the present invention includes, for example, acidic carbon black as an organic pigment,
Various carbon blacks such as basic carbon black and neutral carbon black, various carbon blacks whose surface is modified or coated for improving dispersibility, nigrosine, and organic dyes are referred to as “infrared sensitizing dyes” (Matsuoka Ple
num Press, New York, NY (1990)), US 483312
4, EP-321923, US-4772584, US
-4942141, US-4948776, US-49
48777, US-4948778, US-49506
39, US-4912083, US-4955252,
Various compounds described in the specification such as US-5023229,
Examples of the metal or metal oxide include aluminum, indium tin oxide, tungsten oxide, manganese oxide, titanium oxide and the like, and in addition, conductive polymers such as polypyrrole and polyaniline.

(Binder) When the light-to-heat conversion layer is formed as the mixed film, a binder is used as described above. As the binder, a known binder that dissolves or disperses the light-to-heat conversion material is used. can do. Specific examples of the binder include, for example,
Cellulose such as nitrocellulose and ethyl cellulose;
Acrylates such as cellulose derivatives, polymethyl methacrylate and polybutyl methacrylate, homopolymers and copolymers of methacrylates, polystyrene, homopolymers or copolymers of styrene monomers such as α-methylstyrene, isoprene , Various synthetic rubbers such as styrene-butadiene, homopolymers of vinyl esters such as polyvinyl acetate and copolymers such as vinyl acetate-vinyl chloride, polyurea, polyurethane, polyester, various condensation polymers such as polycarbonate, and
"J. Imaging Sci., P59-64, 30 (2), (1986) (Frechet
") Or" Polymers in Electronics (Symposium Seri
es, P11, 242, T. Davidson, Ed., ACS Washington, DC (198
4) (Ito, Willson) "," Microelectronic Engineerin
g, P3-10, 13 (1991) (E. Reichmanis, LFThompson) "and a binder used in a so-called" chemical amplification system ".

(Additive) When the light-to-heat conversion layer is formed as the mixed film, an additive can be used in addition to the light-to-heat conversion material and the binder. The additives improve the mechanical strength of the light-to-heat conversion layer, improve the laser recording sensitivity, improve the dispersibility of the dispersion in the light-to-heat conversion layer, and form an adjacent layer such as a support or a primer layer. Can be added according to various purposes, such as improving the adhesion to the resin. For example, in order to improve the mechanical strength of the light-to-heat conversion layer, a means for cross-linking the light-to-heat conversion layer is conceivable, and various crosslinking agents can be added.

In order to improve the laser recording sensitivity, it is conceivable to add a known compound which decomposes upon heating to generate a gas. In this case, laser recording sensitivity can be improved by rapid volume expansion of the light-to-heat conversion layer. Examples of these additives include dinitrosopentamethylenetetramine, N, N'-dimethyl-
N, N'-dinitrosoterephthalamide, p-toluenesulfonyl hydrazide, 4,4-oxybis (benzenesulfonyl hydrazide), diamidobenzene and the like.

Known compounds which decompose by heating to form acidic compounds can be used as additives. When these are used in combination with a binder of a chemical amplification system, the decomposition temperature of the constituent material of the light-to-heat conversion layer is greatly reduced, and as a result, laser recording sensitivity can be improved. Examples of these additives include various iodonium salts, sulfonium salts, phosphonium tosylate, oxime sulfonate, dicarbodiimide sulfonate, triazine and the like.

When a pigment such as carbon black is used as the photothermal conversion material, various pigment dispersants are used as additives because the degree of dispersion of the pigment may affect laser recording sensitivity. Further, in order to improve the adhesion, a known adhesion improver (for example, a silane coupling agent, a titanate coupling agent, etc.) may be added. In addition, various additives are used as necessary, such as a surfactant for improving coating properties.

(Thickness of Light-to-Heat Conversion Layer) When the light-to-heat conversion layer is a single film, a thin film is formed by a vapor deposition method, a sputtering method, or the like.
About 100 to 800 °. On the other hand, when the light-to-heat conversion layer is a mixed film, it is formed by coating. In this case, the film thickness is about 0.05 to 10 μm,
0.1-5 μm is preferred. The thickness of the photothermal conversion layer,
If the thickness is too large, undesired results such as a decrease in laser recording sensitivity are given.

[Ink Repellent Layer] The ink repellent layer is a layer having an ink repellent surface. As the ink repellent layer in the invention, a silicone rubber layer is particularly preferred. Hereinafter, a silicone rubber layer which is an example of the ink repellent layer will be described. Silicone rubbers are broadly classified into three types: condensation type silicone rubbers, addition type silicone rubbers, and radiation-curable silicone rubbers. Silicone rubber can be used. The condensation type silicone rubber layer using the condensation type silicone rubber is, for example, a coating formed by curing the following composition A.

<Composition A> (a) 100 parts by weight of diorganopolysiloxane (b) 3 to 70 parts by weight of condensation type crosslinking agent (c) 0.01 to 40 parts by weight of catalyst Diorganopoly of component (a) Siloxane is a polymer having a repeating unit represented by the following general formula (1), wherein R ¹ and R ² each represent an alkyl group having 1 to 10 carbon atoms, a vinyl group, or an aryl group.
It may have other suitable substituents. Generally, it is preferable that 60% or more of R ¹ and R ² be a methyl group, a halogenated vinyl group, a halogenated phenyl group, or the like.

General formula (1)

Embedded image

The diorganopolysiloxane preferably has a hydroxyl group at both ends. The component (a) has a number average molecular weight of 3,000 to 100,000.
Is preferable, and 10,000 to 70,000 is more preferable. The component (b) is not particularly limited as long as it is of a condensation type, and is preferably one represented by the following general formula (2). General formula (2) R ¹ _m · Si · X _n (m + n = 4, n is 2 or more) Here, R ¹ has the same meaning as R ¹ described above, and X
Is a halogen such as Cl, Br, I, H or OH, OCO
R ³ , OR ³ , or the following general formula (3)

General formula (3)

Embedded image

Represents an organic substituent represented by Where R ³
Represents an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ⁴ and R ⁵ each have 1 to 10 carbon atoms.
Represents 10 alkyl groups. The component (c) is a known metal carboxylate containing tin, zinc, lead, calcium, manganese or the like, for example, dibutyltin laurate, lead octylate, lead naphthenate, or a known chloroplatinic acid. Catalyst.

The addition type silicone rubber layer using the addition type silicone rubber is, for example, a film formed by curing the following composition B. <Composition B> (d) 100 parts by weight of a diorganopolysiloxane having an addition-reactive functional group (e) 0.1 to 25 parts by weight of an organohydrogenpolysiloxane (f) 0.00001 to 1 part by weight of an addition catalyst The diorganopolysiloxane having an addition-reactive functional group of the component (d) is an organopolysiloxane having at least two alkenyl groups (more preferably, vinyl groups) directly bonded to a silicon atom in one molecule, and May be at the molecular weight end or in the middle, and examples of the organic group other than the alkenyl group include a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms and an aryl group. The component (d) may optionally have a small amount of a hydroxyl group. The component (d) preferably has a number average molecular weight of 3,000 to 100,000, and 10,000.
~ 70,000 is more preferred.

Examples of the component (e) include polydimethylsiloxane having both terminal hydrogen groups, α, ω-dimethylpolysiloxane and (methylsiloxane) having both terminal methyl groups.
(Dimethylsiloxane) copolymer, cyclic polymethylsiloxane, polymethylsiloxane having trimethylsilyl groups at both terminals, (dimethylsiloxane) (methylsiloxane) copolymer having trimethylsilyl groups at both terminals, and the like. The component (f) is arbitrarily selected from known compounds, and is particularly preferably a platinum-based compound, such as platinum alone, platinum chloride, chloroplatinic acid, and olefin-coordinated platinum. In order to control the curing rate of these compositions, organopolysiloxanes containing vinyl groups such as tetracyclo (methylvinyl) siloxane, alcohols containing carbon-carbon triple bonds, acetone, methyl ethyl ketone, methanol, ethanol, propylene glycol monomethyl ether And the like.

The radiation-curable silicone rubber layer using the radiation-curable silicone rubber is a film formed by curing a silicone base polymer having a functional group polymerizable by irradiation with a radiation by a crosslinking reaction.
A solution obtained by dissolving the silicone base polymer together with an initiator is used as a coating solution, and after application, the entire surface is exposed to radiation. Usually, a silicone-based polymer having an acrylic functional group is used, and crosslinking is generated by irradiation with ultraviolet light.

Regarding these silicone rubbers, “R
& D Report No. 22 Latest Application Technology of Silicone "
(Published by CMC, 1982), Japanese Patent Publication No. 56-23150
And JP-A-3-15553 and JP-B-5-1934. The silicone rubber layer is applied directly on the light-to-heat conversion layer or via another layer therebetween. Incidentally, the silicone rubber layer, if necessary, silica, calcium carbonate, fine powder of inorganic substances such as titanium oxide, silane coupling agent, titanate-based coupling agent and adhesion promoter such as aluminum-based coupling agent and the like. A photopolymerization initiator may be added.

When the silicone rubber layer is thin, there is a problem that the ink resilience is reduced and a scratch is easily formed. On the other hand, when the film thickness is large, the developability is deteriorated. The thickness is preferably from 0.3 to 10 μm,
0.5-5 μm is more preferable, and 1-3 μm is particularly preferable. In the lithographic printing plate precursor described herein, various silicone rubber layers may be further coated on the silicone rubber layer. Further, for protecting the surface of the silicone rubber layer, a transparent film on the silicone rubber layer,
For example, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, cellophane, or the like may be laminated, or a polymer coating may be applied. These films may be used after being stretched. Further, the surface may be subjected to a matting process, but those having no matting process are preferable in the present invention.

[Other Layers] As the other layers, a primer layer is provided on the support in order to improve adhesion to the light-to-heat conversion layer formed on the support, improve printing characteristics, or increase sensitivity. Can be provided. Examples of the primer layer include those obtained by exposing and curing various photosensitive polymers before laminating an upper layer as disclosed in JP-A-60-22903,
The epoxy resin disclosed in Japanese Patent Application Laid-Open No. 0760/133, heat-cured epoxy resin, the one disclosed in Japanese Patent Application Laid-Open No. 63-133151, wherein the epoxy resin is hardened,
-U.S. Pat. No. 2,965,095 discloses a method using a urethane resin and a silane coupling agent.
The one using a urethane resin disclosed in Japanese Patent No. 3248 is cited. In addition, those obtained by hardening gelatin or casein are also effective.

Further, polyurethane, polyamide, styrene / butadiene rubber, carboxy-modified styrene / butadiene rubber, acrylonitrile /
Polymers such as butadiene rubber, carboxy-modified acrylonitrile / butadiene rubber, polyisoprene, acrylate rubber, polyethylene, chlorinated polyethylene, chlorinated polypropylene, vinyl chloride / vinyl acetate copolymer, nitrocellulose, halogenated polyhydroxystyrene, and chlorinated rubber It may be added. The addition ratio is arbitrary, and the primer layer may be formed with only the additives as long as the film layer can be formed. Further, these primer layers may contain additives such as an adhesion aid (for example, a polymerizable monomer, a diazo resin, a silane coupling agent, a titanate coupling agent or an aluminum coupling agent) and a dye. After the application, it can be cured by exposure.

The primer layer is an ink repellent layer.
Ink-receiving layer when the silicone rubber layer is removed
Non-ink receptive like metal supports
Is particularly useful in the case of the support described in In addition, the plastic
The immer layer is used to relieve pressure on the ink repellent layer during printing
Also has a role as a cushion layer. Generally, before
The coating amount of the primer layer is 0.05 to
10g / m ^TwoAbout 0.1 to 8 g / m^TwoIs preferred
0.2 to 5 g / m^TwoIs more preferred.

[0053]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Example 1) [Formation of photothermal conversion layer] Corona-treated surface 188 in thickness
μm polyethylene terephthalate film (trade name E
5101, manufactured by Toyobo Co., Ltd.)
The following coating solution was applied so that the film thickness after drying was 1 μm, to form a photothermal conversion layer. -55 g of the following carbon black dispersion liquid-Nitrocellulose (containing 30% of 2-propanol, degree of polymerization 80, manufactured by Nacalai Tesque) 4.0 g-Propylene glycol monomethyl ether 45 g

<Preparation of Carbon Black Dispersion> The following mixture was dispersed for 30 minutes using a paint shaker, and the glass beads were filtered off to prepare the above carbon black dispersion. -Carbon black (# 40, manufactured by Mitsubishi Chemical Corporation) 5.0 g-Crisbon 3006LV (polyurethane manufactured by Dainippon Ink & Chemicals, Inc.) 4.0 g-Nitrocellulose (containing 30% 2-propanol, polymerization degree 80, 1.3 g of Solsperse S27000 (manufactured by ICI) 0.4 g of propylene glycol monomethyl ether 45 g of glass beads 160 g

[Formation of Ink Repellent Layer] The following coating solution was prepared, applied on the photothermal conversion layer, and heated (110 ° C.,
After drying for 1 minute), a silicone rubber layer having a thickness of 2 μm after drying was formed as an ink repellent layer. 9.00 g of α, ω-divinylpolydimethylsiloxane (degree of polymerization: about 700) ・ 0.60 g of (CH ₃ ) ₃ —Si—O— (SiH (CH ₃ ) —O) ₈ —Si (CH ₃ ) ₃ Polydimethylsiloxane (degree of polymerization: about 8000) 0.50 g ・ Olefin-chloroplatinic acid 0.08 g ・ Inhibitor [HC≡CC (CH ₃ ) ₂ -O-Si (CH ₃ ) ₃ ] 0.07 g ・ Isoper G ( 55 g of a lithographic printing plate precursor for laser recording was obtained by laminating a polypropylene film having a thickness of 12 μm on the surface of the silicone rubber layer obtained as described above.

[Exposure / Development / Cleaning Step] After the cover film of the obtained lithographic printing plate precursor was peeled off, an output of 110 mW, a wavelength of 830 nm was obtained from the silicone rubber layer side.
Using a semiconductor laser having a beam diameter of 10 μm (1 / e ² ), halftone dots of 200 lines / inch were written. Thereafter, the silicone rubber layer was removed from the laser-exposed portion using an automatic processor having the same mechanism as that shown in FIG. As a rubbing member of the developing means, a fiber made of polybutylene terephthalate (hair diameter 150 μm, hair length 11 m)
m), using a brush roller having an outer diameter of 50 mm and implanted in the same direction as the transport direction in the absence of liquid at a speed of 400 / min.
The brush was rotated (the peripheral speed at the tip of the brush was 1.05 m / sec).

As a rubbing member of the cleaning means, a brush roller having an outer diameter of 45 mm into which fibers made of polybutylene terephthalate (hair diameter 50 μm, hair length 9 mm) was implanted, and the following cleaning liquid 1 was sprayed from a spray pipe. Shower ring, 400 rotations per minute in the same direction as the conveyance direction while supplying to the plate (peripheral speed of the tip of the brush is 0.94 m
/ Sec). The lithographic printing plate precursor was transported at a transport speed of 60 cm / min. The contact angle of the following cleaning liquid 1 with respect to the silicone rubber layer was 72 °. In addition, the measurement of the contact angle was performed by the air droplet method at room temperature of 25 ° C. using a contact angle meter CA-A manufactured by Kyowa Interface Science Co., Ltd.

<Cleaning liquid 1> ・ Reodol TW-O106 (Polyoxyethylene sorbitan monooleate, manufactured by Kao Corporation, HLB = 10.0): 2 g ・ Water: 998 g As a result, the silicone rubber layer on the plate surface A sharp edged silicone image having a halftone dot area ratio of 2 to 98% could be formed without any residue or residue.
The lithographic printing plate thus obtained was printed using a printing machine (Mitsubishi Diamond 1F-2, manufactured by Mitsubishi Heavy Industries, Ltd.). 20,000 prints were obtained.

(Comparative Example 1) A lithographic printing plate was manufactured in the same manner as in Example 1 except that tap water was used in place of the washing liquid 1 used for the treatment in the washing means of the automatic processor. . As a result, although a silicone image having a dot area ratio of 2 to 98% was obtained, the residue of the silicone rubber removed from the silicone rubber layer in the portion exposed to the laser was removed by the silicone rubber layer in the non-image portion and the laser exposure. Was adhered on the image portion. The obtained lithographic printing plate is printed on a printing machine (Mitsubishi Diamond 1F-2, Mitsubishi Heavy Industries, Ltd.)
Manufactured), soaking occurred in the image portion of the printed matter.

(Comparative Example 2) In Example 1, the structure of the developing means of the automatic processor was the same as that of the washing means of the automatic processor so that liquid could be supplied to the plate surface and the brush roller. Wash liquid 1 from spray pipe
Was prepared in the same manner as in Example 1 except that the lithographic printing plate was subjected to showering, supplied to the plate surface, and rubbed. As a result, no scum of the silicone rubber layer adhered or remained on the plate surface, but the image reproducibility of the highlight portion deteriorated, and only a silicone image having a dot area ratio of 5 to 98% was obtained. Was.

Example 2 [Support] A polyethylene terephthalate film having a thickness of 175 μm was used as a support, and a coating solution having the following composition was applied thereon, and heated (100 ° C., 1 minute) and dried. Then, a primer layer having a thickness of 0.2 μm after drying was formed.

[0063]

Embedded image

[Formation of Light-to-Heat Conversion Layer] On the primer layer formed on the polyethylene terephthalate support, Ti was vapor-deposited by resistance heating under a vacuum deposition degree of 5 × 10 ⁻⁵ Torr to obtain a light-to-heat conversion layer. A layer was formed. At this time, the thickness of the light-to-heat conversion layer was 200 °, and the optical density was 0.1%.
It was 6.

[Formation of Ink Repellent Layer] The following coating liquid was applied on the photothermal conversion layer, and heated (110 ° C., 2 minutes).
By drying, a silicone rubber layer having a thickness of 2 μm after drying was formed as an ink repellent layer to obtain a lithographic printing plate precursor for laser recording.・ Α, ω-dihydroxypolydimethylsiloxane (degree of polymerization: about 900) 9.00 g ・ Methyltriacetoxysilane 1.00 g ・ Dimethyldiacetoxysilane 1.00 g ・ Dibutyltin octylate 0.01 g ・ Isoper G (Esso Chemical Co., Ltd.) Made) 120g

[Exposure / Development / Washing Step] As in Example 1, halftone dots of 200 lines / inch were written on the resulting lithographic printing plate precursor. Thereafter, the silicone rubber layer was removed from the laser-exposed portion using an automatic processor having the same mechanism as that shown in FIG. The rubbing member of the developing means has an outer diameter of 50 μm in which fibers made of polybutylene terephthalate (hair diameter 200 μm, hair length 13 mm) are implanted.
Using a brush roller of mm, the brush was rotated 350 times per minute in the same direction as the transport direction (the peripheral speed at the tip of the brush was 0.92 m / sec) in the absence of liquid.

As the rubbing member of the washing means, nylon 6.10 fiber (hair diameter 70 μm, hair length 9 m)
m), the following washing liquid 2 is showered from a spray pipe using a brush roller having an outer diameter of 45 mm, and is supplied to the plate surface, while being rotated 350 times per minute in the same direction as the conveying direction (the peripheral speed at the tip of the brush). 0.82 m / sec). The lithographic printing plate precursor is transported at a transport speed of 50 cm.
/ Min. The contact angle of the following cleaning liquid 2 with respect to the silicone rubber layer was 62 °. The contact angle was measured using a contact angle meter CA-A manufactured by Kyowa Interface Science Co., Ltd.
The test was performed at room temperature of 25 ° C. by the in-air droplet method.

<Cleaning liquid 2> Pluronic L61 (polypropylene glycol ethylene oxide adduct, Asahi Denka Kogyo Co., Ltd., HLB = 5.7) 5 g Silicone defoamer) 0.1 g Water 995 g

As a result, the scum of the silicone rubber layer does not adhere to or remain on the plate surface, and
An 8% sharp edge silicone image could be formed. The lithographic printing plate obtained in this way is
When printing was performed using (Mitsubishi Diamond 1F-2, manufactured by Mitsubishi Heavy Industries, Ltd.), 20,000 good prints were obtained without stains in the non-image area and no exudation in the image area.

(Comparative Example 3) A lithographic printing plate was manufactured in the same manner as in Example 2 except that tap water was used as the washing liquid 2 for the treatment in the washing means of the automatic processor. . As a result, although a silicone image having a dot area ratio of 2 to 98% was obtained, the residue of the silicone rubber removed from the silicone rubber layer in the portion exposed to the laser was removed by the silicone rubber layer in the non-image portion and the laser exposure. Was adhered on the image portion. The obtained lithographic printing plate is printed on a printing machine (Mitsubishi Diamond 1F-2, Mitsubishi Heavy Industries, Ltd.)
Manufactured), soaking occurred in the image portion of the printed matter.

(Comparative Example 4) In Example 2, the structure of the developing means of the automatic processor was the same as the structure of the washing means of the automatic processor so that liquid could be supplied to the plate surface and the brush roller. Wash liquid 2 from spray pipe
Was prepared in the same manner as in Example 2 except that was subjected to showering, supplied to the plate surface, and rubbed. As a result, the residue of the silicone rubber layer adhered to the plate surface and did not remain, but the image reproducibility of the highlight portion was deteriorated, and only a silicone image having a dot area ratio of 5 to 98% was obtained. .

(Embodiment 3) In Embodiment 1, Embodiment 1
In the same manner as in Example 1 except that the silicone rubber layer of the portion exposed to the laser was removed under the following conditions using an automatic processor having the same mechanism as that of FIG. To produce a lithographic printing plate. As the rubbing member of the developing means, fifteen polyurethane rubber blades (blade thickness 1 mm, width 4 mm, rubber hardness 45 degrees) were spirally arranged at an angle of 45 degrees on the surface of the roller body member and had an outer diameter of 50 mm. Using a blade roller, in the absence of liquid, the blade was rotated at 400 revolutions per minute in the same direction as the transport direction (the peripheral speed of the tip of the blade was 1.05 m / sec).

As the rubbing member of the washing means, fibers made of nylon 6.10 (hair diameter 70 μm, hair length 14 μm) were used.
mm), the cleaning liquid 1 is showered from a spray pipe using two brush rollers with an outer diameter of 45 mm, and is supplied to the plate surface, while being rotated 400 times per minute in the same direction as the transport direction (the circumference of the tip of the brush). Speed 0.94m / sec)
I let it. The lithographic printing plate precursor is transported at a transport speed of 50 c.
m / min. The lithographic printing plate obtained in this manner is used as a printing machine (Mitsubishi Diamond 1F-2, Mitsubishi Heavy Industries, Ltd.)
And 20,000 sheets of good printed matter without stains in the non-image area and no exudation in the image area were obtained.

(Embodiment 4) In Embodiment 2, Embodiment 2
Example 2 was repeated except that the silicone rubber layer of the portion exposed to the laser was removed under the same conditions as in Example 3, except that the automatic processor used in Example 3 was used instead of the automatic processor used in Example 3. A lithographic printing plate was produced in the same manner as described above. When the lithographic printing plate thus obtained was printed using (Mitsubishi Diamond 1F-2, manufactured by Mitsubishi Heavy Industries, Ltd.), a good printed matter free of stains in the non-image area and exfoliation of the image area was obtained. 20,000 sheets were obtained.

[0075]

According to the present invention, when forming an image by removing the ink repellent layer in the laser-exposed portion, there is no stain on the non-image portion which is a problem at the time of printing. It is possible to provide a method for producing a lithographic printing plate in which a substance that causes detachment does not remain on the plate surface.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an automatic processor preferably used in the method for producing a lithographic printing plate of the present invention.

FIG. 2 is a schematic view showing another example of an automatic processor preferably used in the method for producing a lithographic printing plate of the present invention.

[Explanation of symbols]

 1a rotating brush roller (developing means) 1b rotating brush roller (cleaning means) 1c rotating brush roller (cleaning means) 1d rotating brush roller (cleaning means) 2 roller cradle 3 transport roller 4 transport guide plate 5 spray pipe 6 pipeline 7 Filter 8 Circulation pump 9 Plate feed table 10 Plate discharge table 11 Lithographic printing plate precursor 12 Cleaning liquid tank 13 Developing means 14 Cleaning means 15 Rotating blade rubber roller (developing means) 16 Roller cover 17 Transport base 18 Drain

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AA04 AB03 AC08 AD03 CA50 CB04 DA01 DA19 EA04 FA10 FA24 2H084 AA30 AA32 AE05 BB13 CC05 2H096 AA06 BA20 CA03 CA12 EA04 EA30 GA60 HA30

Claims (1)

[Claims] 1. A step of subjecting a lithographic printing plate precursor obtained by laminating a light-to-heat conversion layer and an ink repellent layer on a support in this order to laser exposure, and provided in a developing means in the absence of a liquid. A developing step of rubbing the surface of the ink repellent layer with a rubbing member, and a cleaning step of rubbing the surface of the ink repellent layer with a rubbing member provided in a cleaning means in the presence of a cleaning solution containing a surfactant. A method for producing a lithographic printing plate, which is performed sequentially.