JP2006130911A - Manufacturing method of dampening water-free lithographic printing form original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of water-free lithographic printing form original plate, in which the flawing of non-image part in a developing treatment process, a printing process or the like is suppressed and also the problem of a printed matter from being stained with ink is suppressed. <P>SOLUTION: In the manufacturing method of a dampening water-free lithographic printing form original plate, which is formed by laminating at least a photothermic conversion layer and a silicone rubber layer in a support in the order named, the photothermic conversion layer is directly provided on the surface being treated with corona discharge of the support, which is left behind for from at least ten minutes to not more than one month after being treated with the corona discharge of 0.01-0.12 kW/m<SP>2</SP>/min thereon or after treating the surface of the support with the corona discharge so as to set the atomic ratio between oxygen/carbon of the surface of the support measured by an X ray photoelectron spectroscopy (ESCA) to be at least 0.41. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a highly sensitive fountain solution-free lithographic printing plate precursor (hereinafter referred to as a waterless lithographic printing plate precursor) capable of printing without the need for fountain solution, which can form an image by heat mode recording with a laser beam. More particularly, the present invention relates to a method for producing a waterless lithographic printing plate precursor having excellent scratch resistance.

In conventional printing methods that require dampening water, it is difficult to control the delicate balance between dampening water and ink, which causes emulsification of ink and ink mixing with dampening water, resulting in poor ink density and soiling. And has a major problem such as causing waste paper. In contrast, waterless lithographic printing plate precursors have a number of advantages because they do not require fountain solution.
On the other hand, recent printing systems such as prepress systems, image setters, and laser printers have made rapid progress in digitizing printed images, and printing plates can be obtained by new plate making methods such as computer-to-plate and computer-to-cylinder. As methods are proposed, new types of printing materials for these printing systems are desired and are being developed.

As an example of a water-less lithographic printing plate precursor capable of laser writing, a layer containing a laser light absorber such as carbon black and a binder or a metal thin film layer that converts light into heat (hereinafter referred to as a photothermal conversion layer). .) A lithographic printing plate precursor on which an ink-repellent silicone rubber layer is provided. By irradiating the lithographic printing plate precursor with a laser, the silicone rubber layer in the irradiated area is removed to form an ink adhering area (image area), and the unirradiated silicone rubber layer remaining area becomes an ink repellent area (non-image area). Thus, waterless printing is possible.
Such a waterless lithographic printing plate precursor is low in manufacturing cost and forms an image by utilizing the ablation of the photothermal conversion layer of the laser irradiation part. It has the merit that the silicone rubber layer can be pushed up and the subsequent removal of the silicone rubber layer in the laser irradiation part (hereinafter also referred to as development) can be performed efficiently.

  Further, such a waterless lithographic printing plate precursor is mounted in a printing press plate cylinder in a roll form, and is supplied onto the plate cylinder so that the printing surface of the waterless lithographic printing plate precursor is on the front side, A mode in which spooling is performed so that a new surface of a waterless lithographic printing plate precursor is positioned in a printing region on the plate cylinder, laser scanning is performed imagewise on the plate cylinder, and printing is performed after removing the silicone rubber layer in the laser irradiation portion. (For example, refer to Patent Document 1).

  However, such a waterless lithographic printing plate precursor is liable to cause a trouble that a non-image portion is scratched in a development processing step and a printing step after writing and recording with a laser. For example, if the development process is a method in which the silicone rubber layer of the laser irradiation part is removed by rubbing the plate surface with a development pad or brush impregnated with a development processing solution, dust adhering to the development pad etc. As a result, fine cracks or peeling may occur in the non-image area, resulting in printed ink stains.

As means for improving the scratching of the silicone rubber layer, has been proposed to apply a corona discharge treatment to the support, the conditions of the corona discharge treatment (treatment amount) of 1W / m ² / min ~200W / m ² / min It is described that it is effective (see Patent Document 2). Further, in the lithographic printing plate precursor having a heat-sensitive layer containing carbon black and a polymer binder on the support, and further having a hydrophilic layer or an oleophobic layer on the heat-sensitive layer, the carbon black is oxidized. It is known that the use of such a material has good scratch resistance, printing durability and image reproducibility (see Patent Document 3).
International Publication No. 90/02045 Pamphlet Japanese Patent Laid-Open No. 11-245529 JP 2002-240552 A

  However, in the corona discharge, unnecessary damage and residue are generated on the surface of the support, the adhesion between the support and the photothermal conversion layer is deteriorated, the non-image area is scratched, and the printed product ink may be stained. In addition, the effect of improving the scratch resistance by oxidation-treated carbon black is still insufficient.

  An object of the present invention is to solve the above-mentioned problems in a waterless lithographic printing plate precursor that forms an image by utilizing the above-described ablation, and suppresses scratches in a non-image area in a development processing step, a printing step, and the like. And providing a method for producing a waterless lithographic printing plate precursor in which the problem of ink stains on printed matter is suppressed.

As a result of intensive studies, the present inventors have determined that it is important to define the amount of corona discharge treatment of the support and the time from the corona discharge treatment to the provision of the photothermal conversion layer. The present inventors have found that the elemental composition on the surface of the support is important for scratch resistance and have reached the present invention.
That is, the present invention is as follows.
(1) A method for producing a fountain solution-free lithographic printing plate precursor comprising at least a light-to-heat conversion layer and a silicone rubber layer sequentially laminated on a support, and 0.01 to 0.12 kW / m on the support ^A method for producing a dampening-free lithographic printing plate precursor, characterized in that a photothermal conversion layer is directly provided on the corona discharge treated surface after a lapse of 10 minutes to 1 month after the corona discharge treatment of ² / min. .
(2) The method for producing a dampening-free lithographic printing plate precursor as described in (1) above, wherein the support is polyethylene terephthalate that has been biaxially stretched.
(3) The method for producing a fountain solution-free lithographic printing plate precursor as described in (1) or (2) above, wherein the corona discharge treatment amount is 0.06 to 0.09 kW / m ² / min. .
(4) A dampening-free lithographic printing plate precursor obtained by laminating at least a photothermal conversion layer and a silicone rubber layer on a polyethylene terephthalate support, and the support surface measured by X-ray photoelectron spectroscopy (ESCA) A dampening solution is unnecessary, characterized in that a photothermal conversion layer is directly provided on the corona discharge treatment surface after the support surface is subjected to a corona discharge treatment so that the oxygen / carbon element ratio of the water is 0.41 or more A lithographic printing plate precursor.
(5) The method for producing a dampening-free lithographic printing plate precursor as described in any one of (1) to (4) above, wherein the photothermal conversion layer contains oxidized carbon black.
(6) The dampening solution is unnecessary according to (5) above, wherein the content of oxidized carbon black in the photothermal conversion layer is 35% by mass or more based on the total solid content of the photothermal conversion layer A method for producing a lithographic printing plate precursor.

In general, it is well known that after a corona discharge treatment, the surface energy is lowered by gradually adhering a hydrophobic substance to a high energy surface containing a hydroxyl group or a carboxylic acid group generated on the support surface by corona discharge. ing. However, the inventors of the present invention are more effective in the case where the photothermal conversion layer is provided after 10 minutes or more than the planographic printing plate precursor provided with the photothermal conversion layer immediately after the corona discharge treatment of the support. It was found that the scratch resistance was good. The reason for this has not been clarified yet, but immediately after the corona discharge treatment, active species such as radical species are present on the support surface, and if a photothermal conversion layer is provided in this state, the photothermal conversion layer is provided. Among them, for example, a binder and the active species may react and partially decompose, which is considered to adversely affect the scratch resistance. The present inventors have also found that the elemental composition on the surface of the support produced by the corona discharge treatment is important for scratch resistance.
After the corona discharge treatment of the support, by providing a photothermal conversion layer within the time period of the above invention, or by specifying the elemental composition of the support surface generated by the corona discharge treatment, the support and the photothermal conversion layer It was possible to efficiently improve the adhesion of the non-image area, which is the object of the present invention.

  According to the present invention, a waterless lithographic printing plate precursor capable of printing without causing ink stains due to scratches in a non-image part in a printing mode in which an image pattern is formed by laser beam irradiation and removal of a silicone rubber layer in an exposed part. Can be provided.

  A waterless planographic printing plate precursor according to the production method of the present invention is mounted in a printing press plate cylinder in a roll form, and is supplied onto the printing drum so that the image forming surface is on the front side, and based on a digital signal on the printing press. In an embodiment in which an image pattern is formed by scanning exposure of an image with an infrared laser beam and a lithographic printing plate is made, and printing is performed using the printing plate with the same printing machine, a non-image portion in a development process or a printing process Printing with suppressed ink stains due to scratches is possible.

Below, the manufacturing method of the waterless planographic printing plate precursor of this invention is demonstrated in detail.
The waterless planographic printing plate precursor according to the present invention is obtained by sequentially laminating at least a photothermal conversion layer and a silicone rubber layer on a support. Here, “sequential lamination” means that these layers are laminated in the above order, and does not deny the existence of other layers such as an overcoat layer and an intermediate layer. The conversion layer is provided directly on the support. Further, a back layer may be provided on the support opposite to the photothermal conversion layer and the silicone rubber layer.

  First, the support and its corona discharge treatment, which are the features of the present invention, will be described.

[Support]
The support used for the waterless lithographic printing plate precursor according to the present invention must be flexible enough to be set on a normal printing press and can withstand the load applied during printing. Therefore, typical supports include polyesters such as polyethylene terephthalate and polyethylene-2,6-naphthalate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, fluororesin, polycarbonate, polyacetate and polyamide. , Using a plastic film such as polyimide, and a composite of these with paper, metal, or alloy (for example, coated paper in which the upper and lower sides of the paper are sandwiched with polyethylene or polyethylene terephthalate laminated on aluminum) However, it is not limited to these. The plastic film may be any of unstretched, uniaxially stretched, or biaxially stretched, preferably a polyethylene terephthalate film, more preferably a biaxially stretched polyethylene terephthalate film. As this polyethylene terephthalate film, a film containing a cavity can be used as described in JP-A-9-314794.

In the present invention, it is essential to perform corona discharge treatment on the surface of the support on the side where the photothermal conversion layer and the silicone rubber layer are laminated. The amount of corona discharge treatment is generally expressed as a discharge amount per unit area and unit time. The practical range in the present invention is 0.01 to 0.12 kW / m ² / min, preferably 0.06 to 0.09 kW / m ² / min. If it is less than 0.01 kW / m ² / min, an effective effect on scratch resistance cannot be obtained. Moreover, when it exceeds 0.12 kW / m < ² > / min, it will become easy to cause an unnecessary damage with respect to a support body.
However, even with a support treated with the same corona discharge treatment amount, the effect of the corona discharge treatment changes with time after the corona discharge treatment. In one embodiment of the production method of the present invention, the photothermal conversion layer is provided within 10 minutes to 1 month after the corona discharge treatment of the support. A more preferable range of the elapsed time until the photothermal conversion layer is provided after the corona discharge treatment of the support is from 30 minutes to 1 week, more preferably from 1 hour to 3 days. If the elapsed time is less than 10 minutes or more than 1 month, an effective effect on scratch resistance cannot be obtained.
This makes it possible to efficiently improve the adhesion between the support and the light-to-heat conversion layer, and to improve the scratch resistance of the non-image area, which is the object of the present invention.

  In order to allow the support after the corona discharge treatment to elapse for the above period, it is necessary to perform the corona discharge treatment while handling the coiled support in the form of a web, and to let it elapse in the state of being wound, in order to improve productivity and contamination. It is preferable from a viewpoint of adhesion prevention. Moreover, it is preferable that the temperature / humidity environment at this time is 5-45 degreeC and 25-75% RH.

  In another aspect of the present invention, the oxygen / carbon element ratio (hereinafter abbreviated as O / C element ratio) measured by X-ray photoelectron spectroscopy (ESCA) on the surface of polyethylene terephthalate is 0.41 or more. Thus, the object of the present invention can be achieved by performing the corona discharge treatment. More preferably, the O / C element ratio is 0.45 or more. ESCA used here is also called XPS, and is an analytical technique for measuring the kinetic energy of photoelectrons emitted from a surface by irradiating soft X-rays on a solid surface placed in an ultra-high vacuum, Since the escape depth of the photoelectrons is several nm, information on atoms and molecules constituting a layer close to the outermost surface of the solid can be obtained. That is, element composition information on the outermost surface of the support that has a great influence on the adhesion to the layer provided on the support can be obtained.

  By setting the elemental composition on the surface of the support to the above range by corona discharge treatment, the scratch resistance of the non-image area is improved. This is presumed that the corona discharge treatment produced hydroxyl groups and carboxylic acid groups on the surface of the support such as polyethylene terephthalate, which increased the polarity and increased the interaction with the photothermal conversion layer, thereby improving the adhesion. Yes. This effect is further improved by a combination with a photothermal conversion layer containing an oxidized carbon black described later.

  The thickness of the support used in the present invention is 25 μm to 3 mm, preferably 75 μm to 500 μm, but the optimum thickness varies depending on the printing conditions. In general, the thickness is most preferably from 100 μm to 300 μm.

(Photothermal conversion layer)
As the photothermal conversion agent used in the present invention, a known substance having a function of converting laser light used for writing into heat (photothermal conversion) can be used. When the laser light source is an infrared laser, infrared absorption is possible. It has been conventionally known that various organic and inorganic materials that absorb light having a wavelength used for a writing laser, such as pigments, infrared absorbing dyes, infrared absorbing metals, and infrared absorbing metal oxides, can be used. These photothermal conversion agents may be used in the form of mixed films with other components such as binders and additives.

Examples of such photothermal conversion agents include various carbon blacks such as acidic carbon black, basic carbon black, and neutral carbon black, various carbon blacks that have been surface-modified or surface-coated for improving dispersibility, nigrosines, Black pigments such as aniline black and cyanine black, phthalocyanine, naphthalocyanine green pigment, carbon graphite, aluminum, iron powder, diamine metal complex, dithiol metal complex, phenolthiol metal complex, mercaptophenol metal complex, aryl Aluminum metal salts, crystal water-containing inorganic compounds, copper sulfate, chromium sulfide, silicate compounds, metal oxides such as titanium oxide, vanadium oxide, manganese oxide, iron oxide, cobalt oxide, tungsten oxide, indium tin oxide, etc. this Hydroxides of metals, sulfates, further bismuth, tin, tellurium, iron, adding an additive such as metal powder of aluminum preferred.

  In addition to these, "infrared sensitizing dye" (Matsuoka, Plenum Press, New York, NY (1990)), US Pat. No. 4,833,124, European Patent 321923, US Pat. No. 4,772,583, US Patent No. 4942141, US Pat. No. 4,948,776, US Pat. No. 4,948,777, US Pat. No. 4,948,778, US Pat. No. 4,950,639, US Pat. No. 4,912,083, US Pat. No. 4,952,552, US Pat. Examples include various compounds described above, but are not limited thereto.

  Among these, carbon black is particularly preferable from the viewpoints of photothermal conversion, economic efficiency, and handleability. Carbon black is classified into furnace black, lamp black, channel black, roll black, disk black, thermal black, acetylene black, etc., depending on its manufacturing method. Furnace black is a different type of particle size and other aspects. Since it is commercially available and is commercially inexpensive, it is preferably used. In carbon black, the degree of aggregation of primary particles affects the sensitivity of the plate material. When the degree of aggregation of the primary particles of carbon black is high (having a high structure structure), when compared with the same addition amount, the blackness of the plate material does not increase, resulting in a decrease in the absorption rate of the laser beam. Sensitivity will decrease. Moreover, the viscosity of the photothermal conversion layer coating solution becomes high or thixotropic due to the particle aggregation, making it difficult to handle the coating solution, and the coating film is not uniform. On the other hand, when the degree of aggregation is low, the dispersibility of the carbon black is lowered and the plate material sensitivity is likely to be lowered. The degree of aggregation of the primary particles of the carbon black can be compared by the value of the oil absorption amount. The higher the oil absorption amount, the higher the aggregation degree, and the lower the oil absorption amount, the lower the aggregation degree. That is, it is preferable to use carbon black having an oil absorption of 20 to 300 ml / 100 g, more preferably 50 to 200 ml / 100 g.

  Carbon blacks having various particle sizes are commercially available, and the particle size of the primary particles also affects the plate material sensitivity. When the average particle diameter of the primary particles is too small, the photothermal conversion layer itself becomes transparent and cannot absorb the laser light efficiently, so that the plate material sensitivity is lowered. On the other hand, if the particle size is too large, the particles are not dispersed at a high density, the blackness of the photothermal conversion layer does not increase, and the laser beam cannot be absorbed efficiently, and the plate material sensitivity also decreases. That is, it is preferable to use carbon black having an average particle diameter of primary particles in the range of 10 to 50 nm, and more preferably 15 to 45 nm.

Further, by using conductive carbon black, it is possible to improve plate material sensitivity. Electrical conductivity of this time is preferably in the range of 0.01~100Ω ^-1 cm ^-1, more preferably 0.1~10Ω ^-1 cm ^-1. Specifically, “CONDUCTEX” 40-220, “CONDUCTEX” 975BEADS, “CONDUCTEX” 900BEADS, “CONDUCTEX” SC, “BATTERY BLACK” (manufactured by Colombian Carbon Japan Co., Ltd.), # 3000 (Mitsubishi Chemical Corporation) Manufactured by Denka Black) (manufactured by Denki Kagaku Kogyo Co., Ltd.), VULCAN XC-72R (manufactured by Cabot Corporation), and the like are more preferably used.

Of these carbon blacks, oxidized carbon black is particularly effective in the present invention. A well-known thing can be used as this oxidized carbon black. For example, JP-A-48-18186, JP-B-52-2874, JP-A-57-15856, JP-B-46-18368, JP-B-52-13807, JP-B-52-13808 JP-A-3-124773, JP-A-8-3498, JP-A-7-258578, JP-A-10-195331, JP-A-10-212425, JP-A-10-212426, JP-A-10-237349, JP-A-10-330634, JP-A-11-166131, JP-A 2000-7937, JP-A 2000-7938, JP-A-5-171056, JP-A-5-171056 The oxidation treatment described in JP-A-8-199086, JP-A-9-304760, JP-A-9-194775, etc. Over carbon black and the like.

  Oxidized carbon black can be obtained by subjecting various carbon blacks to oxidation treatment. As a method for performing the oxidation treatment, a gas phase oxidation method (plasma treatment) such as an air oxidation treatment method in which contact is made with air in a high temperature atmosphere and a reaction method with nitrogen oxide, ozone, sulfur oxide gas or fluorine gas. Liquid phase oxidation method using nitric acid, potassium permanganate, chlorous acid, sodium hypochlorite, bromine aqueous solution, ozone aqueous solution, hydrogen peroxide, etc. Oxidation treatment is achieved by combining more than one species. By performing the oxidation treatment, oxygen functional groups such as a carbonyl group, a carboxyl group, and a hydroxyl group existing on the surface of the raw material carbon black increase.

  The degree of these oxidation treatments is indicated by the pH and volatile value of carbon black. In the case of the carbon black subjected to oxidation treatment of the present invention, the pH is preferably 6.5 or less, more preferably 2 The volatile content is preferably 1% by mass or more, and more preferably 1.5 to 15% by mass. Here, pH value is calculated | required by measuring the liquid mixture of carbon black and distilled water with a glass electrode meter. Moreover, the value of volatile matter is calculated | required by displaying the reduced mass when carbon black is heated at 950 degreeC for 7 minute (s) as a percentage display. These oxidized carbon blacks may be used alone or in combination of two or more. The effect of the present invention is particularly effective in a region where the content of oxidized carbon black in the photothermal conversion layer is large.

Commercially available products can also be used as the oxidized carbon black used in the present invention.
Specific examples include the following products.
Carbon black manufactured by Mitsubishi Chemical Corporation, # 50, # 2700B, # 2650, # 2450B, # 2400B, # 2350, # 1000, # 970, # 3030B, # 3230B, MA-11, MA-220, MA-230 MA-77, MA-7, MA-8, MA-100R, MA-200RB, MA-14.
MONARCH 1300, MOGUL L, REGAL 400R, VULCAN XC-72R manufactured by CABOT.
COLOR BLACK FW200, COLOR BLACK FW2, COLOR BLACK FW1, COLOR BLACK FW18, COLOR BLACK S170, COLOR BLACK S160, SPECIAL BLACK 550, SPECIAL BLACK 350, SPECIAL BLACK ACK, manufactured by DEGUSSA
250, SPECIAL BLACK 100, PRINTEX 150T, PRINTEX U, PRINTEX V, PRINTEX 140U, PRINTEX 140V.

  The addition amount of the photothermal conversion agent used in the present invention is preferably 10% by mass or more, particularly preferably 35% by mass or more, and preferably 10 to 70% by mass with respect to the total solid mass of the photothermal conversion layer. More preferably, it is 20-60 mass%, More preferably, it is 35 mass%-50 mass%. Within this range, the film strength of the light-to-heat conversion layer does not decrease, and good sensitivity can be obtained without decreasing the adhesion with an adjacent layer.

When the photothermal conversion layer is a single film, metals such as aluminum, titanium, tellurium, chromium, tin, indium, bismuth, zinc, lead, alloys thereof, metal oxides, metal carbides, metal nitrides, metal borons A film containing at least one of chemical compounds, metal fluorides, and organic dyes can be formed on the support by vapor deposition or sputtering.

  When the photothermal conversion layer is a mixed film, the photothermal conversion agent can be dissolved or dispersed in a binder and formed together with other components by a coating method. Known binders that dissolve or disperse the photothermal conversion agent are used as the binder. Examples thereof include cellulose derivatives such as cellulose, nitrocellulose, and ethylcellulose, homopolymers and copolymers of acrylate esters, polymethyl, and the like. Homopolymers and copolymers of methacrylic esters such as methacrylate and polybutyl methacrylate, homopolymers and copolymers of styrene monomers such as acrylic ester-methacrylic ester copolymers, polystyrene, α-methylstyrene, Various synthetic rubbers such as polyisoprene and styrene-butadiene copolymer, homopolymers of vinyl esters such as polyvinyl acetate, vinyl ester-containing copolymers such as vinyl acetate-vinyl chloride copolymer, polyurea, polyurethane , Polyester & polycar Various condensate polymers such as Nate, “J. Imaging Sci., P59-64, 30 (2), (1986) (Frechet et al.)”, “Polymers in Electronics (Symposium Series, P11, 242, T. Davidson, Ed., ACS Washington, DC (1984) (Ito, Willson)) and “Microelectronic Engineering, P3-10, 13 (1991) (E. Reichmanis, L. F. Thompson)”. And binders used in the above.

  Among these, a polyurethane resin is preferable from the viewpoint of adhesion to the silicone rubber layer described later. The polyurethane resin used for the photothermal conversion layer can be obtained by a polyaddition reaction of a diisocyanate compound and a diol compound. Examples of the diisocyanate compound include 2,4-tolylene diisocyanate, dimer of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 4,4 ′. -Aromatic diisocyanate compounds such as diphenylmethane diisocyanate, 4,4 '-(2,2-diphenylpropane) diisocyanate, 1,5-naphthylene diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate; Aliphatic diisocyanate compounds such as methylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, dimer acid diisocyanate; isophorone diisocyanate, 4,4′-methylenebis (cyclohexane Silisocyanate), methylcyclohexane-2,4 (or 2,6) diisocyanate, 1,3- (isocyanatomethyl) cyclohexane, and the like; 1 mol of 1,3-butylene glycol and 2 mol of tolylene diisocyanate And a diisocyanate compound which is a reaction product of a diol and a diisocyanate such as an adduct of

Examples of the diol compound include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, 1,2-dipropylene glycol, 1,2-tripropylene glycol, 1,2-tetrapropylene glycol. 1,3-dipropylene glycol, polypropylene glycol, 1,3-butylene glycol, 1,3-dibutylene glycol, neopentyl glycol, 1,6-hexanediol, 2-butene-1,4-diol, 2, 2,4-trimethyl-1,3-pentanediol, 1,4-bis-β-hydroxyethoxycyclohexane, cyclohexanedimethanol, tricyclodecane dimethanol, bisphenol A, hydrogenated bisphenol A, hydrogenated bisphenol F, bisphenol S, hydroquinone dihydroxyethyl ether, p-xylylene glycol, dihydroxyethyl sulfone, 2,2′-dimethylolpropanoic acid, bis (2-hydroxyethyl) -2,4-tolylene dicarbamate 2,4-Tolylene-bis (2-hydroxyethylcarbamide)
Bis (2-hydroxyethyl) -m-xylylene dicarbamate, bis (2-hydroxyethyl) isophthalate, and the like. Furthermore, the polyether obtained by the condensation reaction of these diol compounds, and the polyester diol obtained by the condensation reaction of dicarboxylic acid compounds, such as adipic acid and terephthalic acid, and the said diol compound can also be mentioned. These polyurethane resins may use a chain linking agent such as a diamine compound, hydrazine, or a hydrazine derivative at the time of synthesis.

  In particular, polyurethanes disclosed in Japanese Patent Application Laid-Open Nos. 2001-188339 and 2002-144749 are used extremely well from the viewpoints of sensitivity and storage stability of the light-sensitive material.

  The amount of the binder used in the photothermal conversion layer of the present invention is preferably 10 to 95% by mass, more preferably 40 to 80% by mass based on the total solid content of the high heat conversion agent.

When forming the photothermal conversion layer as a mixed film, improve the mechanical strength of the photothermal conversion layer, improve the laser recording sensitivity, improve the dispersibility of the photothermal conversion agent in the photothermal conversion layer, Various additives can be added to the photothermal conversion layer according to various purposes such as improving adhesion to a layer adjacent to the photothermal conversion layer.
For example, in order to improve the mechanical strength of the photothermal conversion layer, various crosslinking agents that cure the photothermal conversion layer may be added. Examples of the crosslinking agent include a combination of a polyfunctional isocyanate compound or a polyfunctional epoxy compound and a hydroxyl group-containing compound, a carboxylic acid compound, a thiol compound, an amine compound, a urea compound, and the like. It is not limited. The addition amount of the crosslinking agent used for this invention is 1-50 mass% with respect to the total photothermal conversion layer composition, Preferably, it is 2-20 mass%. When the addition amount is 1% by mass or more, the effect of crosslinking appears, and when it is 50% by mass or less, the film strength of the photothermal conversion layer does not become too strong, and the shock absorber effect when external pressure is applied to the silicone rubber layer Will not disappear and scratch resistance will not be reduced.

  In order to improve the laser recording sensitivity, a known compound that decomposes by heating to generate gas can be added. In this case, the laser recording sensitivity can be improved by rapid volume expansion of the light-to-heat conversion layer. Examples of these additives include dinityropentamethylenetetramine, N, N′-dimethyl-N, N′-dinitrosoterephthalate. Amides, p-toluenesulfonyl hydrazide, 4,4-oxybis (benzenesulfonyl hydrazide), diamidobenzene and the like can be used. In order to improve laser recording sensitivity, various iodonium salts, sulfonium salts, phosphonium tosylate, oxime sulfonate, dicarbodiimide sulfonate, triazine, etc. Known compounds of generators can be used as additives. By using these together with the chemical amplification binder, it is possible to greatly reduce the decomposition temperature of the chemical amplification binder which is a constituent material of the photothermal conversion layer, and as a result, it is possible to improve the laser recording sensitivity. When a pigment such as carbon black is used as the photothermal conversion agent, various pigment dispersants can be used as additives in order to improve the degree of dispersion of the pigment.

The addition amount of the pigment dispersant used for this invention is 1-70 mass% with respect to a photothermal conversion agent, Preferably, it is 5-50 mass%. If the addition amount is 1% by mass or more, the effect of improving the pigment dispersion is obtained, and the plate material sensitivity is not lowered. In order to improve adhesion to adjacent layers, known adhesion improvers such as silane coupling agents and titanate coupling agents, vinyl group-containing acrylate resins, hydroxyl group-containing acrylate resins, acrylamide resins, ethylene-acetic acid You may add the binder with favorable adhesiveness with respect to an adjacent layer, such as a vinyl copolymer, a vinyl chloride-vinyl acetate copolymer, a cellulose derivative, and gelatin. The addition amount of the adhesion improver or adhesion improvement binder used in the present invention is 5 to 70% by mass, preferably 10 to 50% by mass, based on the total photothermal conversion layer composition. If the addition amount is 5% by mass or more, there is an effect of improving the adhesion with an adjacent layer, and if it is 70% by mass or less, the plate material sensitivity does not decrease.

  In order to improve the coating property, a surfactant such as a fluorine-based surfactant or a nonionic surfactant can be used as an additive. The addition amount of the surfactant used for this invention is 0.01-10 mass% with respect to the total photothermal conversion layer composition, Preferably, it is 0.05-1 mass%. When the addition amount is 0.01% by mass or more, it is easy to form a uniform photothermal conversion layer with good coatability, and when the addition amount is 10% by mass or less, the adhesive force between adjacent layers does not decrease. In addition, various additives can be used as necessary.

The dry coating amount of the photothermal conversion layer used in the present invention is usually 0.05 to 10 g / m ² , preferably 0.1 to 5 g / m ² . The photothermal conversion layer used in the present invention is a photothermal conversion layer forming coating solution on a support, and generally known coating methods such as dip coating, air knife coating, curtain coating, wire bar coating, It can be formed by applying and drying by a gravure coating method, an extrusion coating method or the like.

(Silicone rubber layer)
The ink-repellent silicone rubber layer used in the present invention is formed by reacting a silicone rubber film on the photothermal conversion layer. Specifically, it is preferable to form by condensing condensation type silicone with a crosslinking agent or addition polymerization of addition type silicone with a catalyst. When using condensation type silicone, (b) 3 to 70 parts by weight of condensation type crosslinking agent and (c) 0.01 to 40 parts by weight of catalyst are added to 100 parts by weight of diorganopolysiloxane. It is preferred to use a different composition. The component (a) diorganopolysiloxane is a polymer having a repeating unit represented by the following general formula. R ¹ and R ² are an alkyl group having 1 to 10 carbon atoms, a vinyl group, or an aryl group, and may further have a substituent. In general, it is preferable that 60% or more of R ¹ and R ² is a methyl group, a halogenated vinyl group, a halogenated phenyl group or the like.

  Such a diorganopolysiloxane is preferably one having hydroxyl groups at both ends. The component (a) has a number average molecular weight of 3,000 to 600,000, more preferably 5,000 to 100,000. The crosslinking agent of component (b) may be any as long as it is a condensation type, but is preferably one represented by the following general formula.

Here, R ¹ has the same meaning as R ¹ described above, and X represents a halogen atom such as Cl, Br, or I, a hydrogen atom, a hydroxyl group, or an organic substituent as shown below.

In the formula, R ³ represents an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 20 carbon atoms, and R ⁴ and R ⁵ represent an alkyl group having 1 to 10 carbon atoms.

  Component (c) is a known catalyst such as a metal carboxylate such as tin, zinc, lead, calcium, manganese, such as dibutyltin laurate, lead octylate, lead naphthenate, or chloroplatinic acid. Is mentioned.

  When the addition type silicone is used, (d) 0.1 to 25 parts by mass of organohydrogenpolysiloxane with respect to 100 parts by mass of diorganopolysiloxane having an addition reactive functional group, and (f) It is preferable to use a composition to which 0.00001 to 1 part by mass of an addition catalyst is added. The above-mentioned diorganopolysiloxane having an addition-reactive functional group (d) is an organopolysiloxane having at least two alkenyl groups (more preferably vinyl groups) directly bonded to silicon atoms in one molecule. The group may be either at the molecular weight end or in the middle, and may have a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or an aryl group as an organic group other than the alkenyl group. Further, the component (d) optionally has a trace amount of hydroxyl groups. The component (d) has a number average molecular weight of 3,000 to 600,000, more preferably 5,000 to 150,000.

  Component (e) includes polydimethylsiloxane having hydrogen groups at both ends, α, ω-dimethylpolysiloxane, methylsiloxane / dimethylsiloxane copolymer of both ends methyl groups, cyclic polymethylsiloxane, trimethylsilyl groups at both ends. Examples thereof include polymethylsiloxane and a dimethylsiloxane / methylsiloxane copolymer having trimethylsilyl groups at both terminals. The component (f) is arbitrarily selected from known polymerization catalysts, but platinum-based compounds are particularly desirable, and examples thereof include platinum alone, platinum chloride, chloroplatinic acid, and olefin coordinated platinum.

  In order to control the curing rate of the silicone rubber layer in these compositions, vinyl group-containing organopolysiloxanes such as tetracyclo (methylvinyl) siloxane, carbon-carbon triple bond-containing alcohols, acetone, methyl ethyl ketone, methanol, ethanol, It is also possible to add a crosslinking inhibitor such as propylene glycol monomethyl ether. The (D) silicone rubber layer used in the present invention can be formed by applying and drying the above-described silicone-containing composition on the (C) photothermal conversion layer using a solvent. At this time, the silicone rubber layer composition undergoes a condensation reaction or addition reaction when the solvent is dried after application of the coating solution for forming the silicone rubber layer, so that the curing property of the silicone rubber is lowered when the drying temperature is low. There is a risk of poor curing. For this reason, 80 degreeC or more is preferable and, as for the drying temperature after application | coating of a silicone rubber layer, 100 degreeC or more is more preferable.

If necessary, the silicone rubber layer may be a fine powder of an inorganic material such as silica, calcium carbonate, titanium oxide, an adhesion aid such as a silane coupling agent, a titanate coupling agent or an aluminum coupling agent, or photopolymerization. An initiator may be added. The thickness of the silicone rubber layer used in the present invention is preferably 0.5 to 5.0 g / m ² , more preferably 1.0 to 3.0 g / m ² , and even more preferably 1 as a dry film thickness. .5 to 2.0 g / m ² . When the film thickness is 0.5 g / m ² or more, the ink repellency is not lowered, and problems such as scratches are easily eliminated, and when the film thickness is 5.0 g / m ² or less, developability does not deteriorate. . Further, various silicone rubber layers may be further coated on the silicone rubber layer for the purpose of improving printing durability, scratch resistance, image reproducibility, stain resistance and the like to form a surface layer.

[Back layer]
In the waterless planographic printing plate precursor of the present invention, at least one back layer is desirably provided on the side of the support opposite to the surface on which the photothermal conversion layer and the silicone rubber layer are provided.

The back layer is not particularly limited, but a layer in which conductive metal oxide particles are dispersed in a binder is preferable.
Further, the back layer of the present invention may have a layer structure of two or more layers as necessary. When the back layer has a layer structure of two or more layers, in a broad sense, all the layers of the two or more layers are collectively referred to as a back layer, and in a narrow sense, the lower layer is a back layer and a layer above it. May be referred to as an overcoat layer, or may be referred to as a back first layer, a back second layer, or the like from the lower layer. In the examples of the present specification, they are referred to as a back first layer, a back second layer, and the like.
The back layer may contain a matting agent. Further, the back layer may contain a surfactant, a slip agent, a wax and the like.

  The matting agent is preferably an oxide such as silicon oxide, aluminum oxide or magnesium oxide having an average particle size of 0.5 μm to 20 μm, more preferably an average particle size of 1.0 μm to 15 μm, or polymethyl Examples thereof include polymers and copolymers such as methacrylate and polystyrene. In particular, crosslinked particles of these polymers or copolymers are preferred.

  By containing a predetermined amount of these matting agents in at least one layer on the back layer side (back and / or overcoat layer), the Beck smoothness (second) on the surface on the back layer side is preferably 50 to 500 seconds, preferably May be 60 to 450 seconds, more preferably 200 to 400 seconds. Here, the Beck smoothness (second) of the surface on the back layer side is JIS-P8119-1998 and J.P. TAPPI paper pulp test method no. 5 means the value measured by the method described in 5. By making the Beck smoothness (seconds) on the surface on the back layer side 50 seconds or more, the unevenness on the surface on the back side is not too large and the matting agent is difficult to fall off the layer, and the transportability of the original plate decreases with time. do not do. On the other hand, if the Beck smoothness (seconds) on the surface on the back layer side is 500 seconds or less, the smoothness on the back layer side is not too high and the transportability of the original plate does not deteriorate, and various adverse effects due to poor transport occur. Absent.

The back layer may contain conductive metal oxide particles. Examples of the material of the conductive metal oxide particles include ZnO, TiO ₂ , SnO ₂ , Al ₂ O ₃ , In ₂ O ₃ , MgO, BaO and MoO ₃ and their composite oxides, and / or the metal oxide. Mention may be made of metal oxides containing different atoms.

As the metal oxide, SnO ₂ , ZnO, Al ₂ O ₃ , TiO ₂ , In ₂ O ₃ and MgO are preferable, SnO ₂ , ZnO, In ₂ O ₃ and TiO ₂ are more preferable, and SnO ₂ is particularly preferable. . Examples of containing a small amount of different atoms include Zn or Al, In, TiO ₂ Nb or Ta, In ₂ O ₃ Sn, and SnO ₂ Sb, Nb or halogen elements. An element doped with 0.01 to 30 mol% (preferably 0.1 to 10 mol%) of the element can be used. When the amount of the different element added is 0.01 mol% or more, sufficient conductivity can be imparted to the oxide or composite oxide, and the blackening degree of the particles is increased by setting it to 30 mol% or less. The back layer is not black and is suitable for a sensitive material. Therefore, in the present invention, the material for the conductive metal oxide particles is preferably a material containing a small amount of a different element with respect to the metal oxide or the composite metal oxide. Also preferred are those containing an oxygen defect in the crystal structure.

  The conductive metal oxide particles are preferably contained in the back layer in the range of 10 to 1000% by mass, and more preferably in the range of 100 to 800% by mass with respect to the total mass of the binder. When the content is 10% by mass or more, sufficient antistatic properties can be obtained, and when the content is 1000% by mass or less, dropping of the conductive metal oxide particles from the photosensitive material can be prevented.

The particle diameter of the conductive metal oxide particles is preferably as small as possible in order to reduce light scattering as much as possible, but should be determined using the ratio of the refractive index of the particles to the binder as a parameter, and Mie's theory Can be obtained using
The average particle diameter of the metal oxide particles in the back layer of the waterless planographic printing plate precursor of the present invention is preferably 0.001 to 0.5 μm, more preferably 0.003 to 0.2 μm. is there. Here, the average particle size is a value including not only the primary particle size of the conductive metal oxide particles but also the particle size of the higher order structure.

  When the fine particles of the metal oxide are added to the coating solution for forming the back layer, they may be added and dispersed as they are, but they are dispersed in a solvent such as water (including a dispersant and a binder as necessary). It is preferable to add a dispersion.

In the present invention, by adding the above-described metal oxide particles of the present invention to the back layer, the surface electrical resistance value at 10 ° C. and 15% RH on the back layer side of the original is 1 × 10 ⁷ to 1 × 10 ¹² Ω, Preferably, it can be adjusted to 1 × 10 ⁹ to 1 × 10 ¹¹ Ω, and the surface electrical resistance value under high temperature and high humidity can also be adjusted to a predetermined value. When the surface electrical resistance value at 10 ° C. and 15% RH on the back layer side of the waterless planographic printing plate precursor is set to 1 × 10 ⁷ Ω or more, a large amount of conductive metal oxide particles are unnecessary, so these particles fall off. It is difficult to cause a secondary failure such that the dropped particles become the core of the repellency of the coating film. Further, if it is 1 × 10 ¹² Ω or less, it has a desired antistatic property even under high temperature and high humidity, and prevents coating defects during the production of a waterless lithographic printing plate precursor under high temperature and high humidity, The focus shift of the laser beam can be prevented at the time of recording writing due to adhesion of dust or the like to the waterless lithographic printing plate precursor, and the sharpness (reproducibility) of image recording can be improved.

  Although it does not specifically limit as a binder used for the back layer of the waterless planographic printing plate precursor used for the platemaking method of this invention, The hardened | cured material of an acrylic resin and a melamine compound is desirable. In the present invention, from the viewpoints of maintaining a good working environment and preventing air pollution, it is preferable to use either a water-soluble polymer or a melamine compound, or an aqueous dispersion such as an emulsion. Moreover, it is preferable that a polymer has any group of a methylol group, a hydroxyl group, a carboxyl group, and a glycidyl group so that a crosslinking reaction with a melamine compound is possible. Among these, a hydroxyl group and a carboxyl group are preferable, and a carboxyl group is particularly preferable. The content of the hydroxyl group or carboxyl group in the polymer is preferably 0.0001 to 10 equivalent / 1 kg, and particularly preferably 0.01 to 1 equivalent / 1 kg.

Acrylic resins include acrylic acid esters such as acrylic acid and alkyl acrylate, acrylamide, acrylonitrile, methacrylic acid esters such as methacrylic acid and alkyl methacrylate, and homopolymers of any monomer of methacrylamide and methacrylonitrile. Or the copolymer obtained by superposition | polymerization of 2 or more types of these monomers can be mentioned. Among these, homopolymers of monomers of acrylic acid esters such as alkyl acrylates and methacrylic acid esters such as alkyl methacrylates, or copolymers obtained by polymerization of two or more of these monomers preferable. For example, mention may be made of homopolymers of monomers of acrylic acid esters and methacrylic acid esters having an alkyl group having 1 to 6 carbon atoms, or copolymers obtained by polymerization of two or more of these monomers. it can.

  The acrylic resin is mainly composed of a monomer having any one of a methylol group, a hydroxyl group, a carboxyl group and a glycidyl group so that a crosslinking reaction with the melamine compound is possible with the composition as a main component. The resulting polymer.

  The melamine compound used in the present invention includes a compound containing two or more (preferably three or more) methylol groups or alkoxymethyl groups in the melamine molecule, and a melamine resin or melamine urea that is a condensation polymer thereof. Examples thereof include resins.

  Examples of the initial condensate of melamine and formalin include dimethylol melamine, trimethylol melamine, tetramethylol melamine, pentamethylol melamine, hexamethylol melamine and the like. Specific examples of commercially available products include, for example, SMITEX RESIN ( (Sumitex Resin) M-3, MW, MK and MC (manufactured by Sumitomo Chemical Co., Ltd.), and the like, but are not limited thereto.

  Examples of the condensation polymer include hexamethylol melamine resin, trimethylol melamine resin, trimethylol trimethoxymethyl melamine resin, and the like. Commercially available products include MA-1 and MA-204 (Sumitomo Bakelite Co., Ltd.), Bekkamin MA-S, Bekkamin APM and Bekkamin J-101 (Dainippon Ink Chemical Co., Ltd.), Euroid 344 ( Examples include, but are not limited to, Mitsui Toatsu Chemical Co., Ltd.), Oka Resin M31, and Oka Resin PWP-8 (Oshika Promotion Co., Ltd.).

  As said melamine compound, it is preferable that the functional group equivalent shown by the value which divided the molecular weight by the number of functional groups in 1 molecule is 50-300. Here, the functional group represents a methylol group or an alkoxymethyl group. When this value is 300 or less, the curing density becomes moderate and high strength is obtained. When the functional group equivalent is 50 or more, the curing density is appropriate, transparency is not impaired, and the quality is improved. The amount of the aqueous melamine compound added is 0.1 to 100% by mass, preferably 10 to 90% by mass, based on the polymer.

  These melamine compounds may be used alone or in combination of two or more. Further, it can be used in combination with other compounds. E. K. Meers and T.W. H. "The Theory of the Photographic Process" by James, 3rd edition (1966), U.S. Patent Nos. 3316095, 3232264, 3288775, 27332303, 3635718, 3323716, 2732616, 258616 No. 3103437, No. 3017280, No. 2998611, No. 2725294, No. 2725295, No. 3100704, No. 3091537, No. 3321313, No. 3543292 and No. 312449, and British Patent Nos. 994869 and 1167207. The curing agent described in No. etc. is mentioned.

Representative examples of the curing agent include mucochloric acid, mucobromic acid, mucofenoxycyclolic acid, mucophenoxypromic acid, formaldehyde, glyoxal, monomethylglioxal, 2,3-dihydroxy-1,4 dioxane, 2,3 Aldehyde compounds such as dihydroxy-5-methyl-1,4-dioxanesuccinaldehyde, 2,5-dimethoxytetrahydrofuran and glutaraldehyde and derivatives thereof; divinylsulfone-N, N′-ethylenebis (vinylsulfonylacetamide), 1 , 3-bis (vinylsulfonyl) -2-propanol, methylene bismaleimide, 5-acetyl-1,3-diaacryloyl-hexahydro-s-triazine, 1,3,5-triacryloyl-hesahydro-s
Active vinyl compounds such as triazine and 1,3,5-trivinylsulfonyl-hexahydro-s-triazine; 2,4-dichloro-6-hydroxy-s-triazine sodium salt, 2,4-dichloro-6- ( Active halogens such as 4-sulfoanilino) -s-triazine sodium salt, 2,4-dichloro-6- (2-sulfoethylamino) -s-triazine and N, N′-bis (2-chloroethylcarbamyl) piperazine Compounds: bis (2,3-epoxypropyl) methylpropylammonium p-toluenesulfonate, 1,4-bis (2 ′, 3′-epoxypropyloxy) butane, 1,3,5-triglycidyl isocyanate Nurate, 1,3-diglycidyl-5- (γ-acetoxy-β-oxypropyl) isocyanurate, sorbitol Liglycidyl ethers, polyglycerol polyglycidyl ethers, pentaerythritol polyglycidyl ethers, diglycerol polyglycidyl ether, 1,3,5-triglycidyl (2-hydroxyethyl) isocyanurate, glycerol polyglycerol ethers and trimethylol Epoxy compounds such as propane polyglycidyl ethers; ethylene such as 2,4,6-triethylene-s-triazine, 1,6-hexamethylene-N, N′-bisethyleneurea and bis-β-ethyleneiminoethylthioether Imine compounds; methanesulfonic acid ester compounds such as 1,2-di (methanesulfoneoxy) ethane, 1,4-di (methanesulfoneoxy) butane and 1,5-di (methanesulfoneoxy) pentane; Carbodiimide compounds such as silcarbodiimide and 1-dicyclohexyl-3- (3-trimethylaminopropyl) carbodiimide hydrochloride; isoxazole compounds such as 2,5-dimethylisoxazole; inorganic compounds such as chromium alum and chromium acetate; Dehydrated condensed peptide reagents such as N-carboethoxy-2-isopropoxy-1,2-dihydroquinoline and N- (1-morpholinocarboxy) -4-methylpyridinium chloride; N, N′-adipoyldioxydi Active ester compounds such as succinimide and N, N′-terephthaloyldioxydisuccinimide: isocyanates such as toluene-2,4-diisocyanate and 1,6-hexamethylene diisocyanate; and polyamide-polyamine-epichlorohydrin reactant Et Although a chlorohydrin type compound can be mentioned, it is not limited to this.

  Examples of the surfactant include known anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants.

  Examples of the slip agent include phosphate esters of higher alcohols having 8 to 22 carbon atoms or amino salts thereof; palmitic acid, stearic acid, behenic acid and esters thereof; and silicone compounds.

  The back layer is a dispersion obtained by dispersing the above components as they are or in a solvent such as water (including a dispersant and a binder as necessary) into an aqueous dispersion or aqueous solution containing a binder and appropriate additives. It is obtained by adding and mixing (dispersing if necessary) to prepare a coating solution for forming a back layer and coating and drying it.

  The back layer is a coating method generally known on the surface of the support (the side where the photothermal conversion layer and the silicone rubber layer are not provided), such as dip coating, air knife coating, It can be applied by a curtain coating method, a wire bar coating method, a gravure coating method, an extrusion coating method or the like.

  The thickness of the back layer is not particularly limited, but is preferably in the range of 0.01 to 1 μm, and more preferably in the range of 0.1 to 0.5 μm. When it is 0.01 μm or more, it is easy to apply the coating agent uniformly, and uneven application is unlikely to occur on the product.

[Plate making method]
Next, a method for making a lithographic printing plate from a waterless lithographic printing plate precursor according to the present invention will be described. In the same way as the general plate making method, the plate making is performed by removing the silicone rubber layer with reduced exposure and the exposure step for reducing the adhesion with the adjacent layer of the silicone rubber layer in the exposed portion by imagewise exposure, And a developing step for forming a receptive region.

(I) Exposure Step The laser used to expose the waterless lithographic printing plate precursor according to the present invention provides an exposure amount that causes a decrease in adhesion sufficient to peel and remove the silicone rubber layer. It must be. As long as the above conditions are satisfied, there are no particular limitations on the type of laser, and gas lasers such as Ar lasers and carbon dioxide lasers, solid lasers such as YAG lasers, and semiconductor lasers can be used. A laser with a normal output of 50 mW class or higher is required. From practical aspects such as maintainability and cost, a semiconductor laser and a semiconductor-excited solid laser (YAG laser or the like) are preferably used. The recording wavelength of these lasers is in the infrared wavelength region, and an oscillation wavelength of 800 nm to 1100 nm is often used. It is also possible to perform exposure using an imaging apparatus described in JP-A-6-186750, a full color printing system “Quickmaster DI46-4” (trade name) manufactured by Heidelberg, or the like.

(II) Development step The developer used for making a lithographic printing plate from the waterless lithographic printing plate precursor according to the present invention is known as a developer for a waterless lithographic printing plate precursor, such as hydrocarbons, Polar solvents, water, and combinations thereof can be used, but from the viewpoint of safety, it is preferable to use water or an aqueous solution of an organic solvent containing water as a main component, and considering the safety and flammability, the organic solvent The concentration of is desirably less than 40% by mass. As hydrocarbons that can be used, aliphatic hydrocarbons (specifically, for example, hexane, heptane, gasoline, kerosene, commercially available solvents “Isopar E, H, G” (Esso Chemical Co., Ltd.), etc.) , Aromatic hydrocarbons (for example, toluene, xylene, etc.), halogenated hydrocarbons (tricrene, etc.), and the like. Examples of polar solvents include alcohols (specifically, for example, methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene Glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether, polypropylene glycol, tetraethylene glycol, etc.), ketones (eg, acetone, methyl ethyl ketone, etc.), esters (eg, ethyl acetate, lactic acid) Methyl, butyl lactate, propylene glycol monomethyl ether acetate, diethyl Glycol acetate, diethyl phthalate), other, triethyl phosphate, tricresyl phosphate and the like. Moreover, water itself, such as tap water, pure water, distilled water, can also be used. These may be used alone or in combination of two or more. For example, water may be added to hydrocarbons, water may be added to polar solvents, or hydrocarbons and polar solvents may be used in combination. Further, among the hydrocarbons and polar solvents having a low affinity for water, a surfactant or the like may be added to improve the solubility in water. Further, an alkali agent (for example, sodium carbonate, diethanolamine, sodium hydroxide, etc.) can be added together with the surfactant.

The development can be performed by a known method such as rubbing the plate surface with a developing pad containing the developer as described above, or rubbing with a developing brush in water after pouring the developer onto the plate surface. The developer temperature can be any temperature, but is preferably 10 ° C to 50 ° C. As a result, the silicone rubber layer which is the ink repellent layer in the image portion is removed, and that portion becomes the ink receiving portion. The development processing as described above, or the subsequent washing and drying processing can be performed by an automatic processor. A preferred example of such an automatic processor is described in JP-A-2-220061. Further, by using the above-described full color printing system “Quickmaster DI46-4” manufactured by Heidelberg, exposure and on-press development can be continuously performed under suitable conditions.

  The waterless planographic printing plate precursor of the present invention can also be developed by peeling off the adhesive layer after the adhesive layer is bonded to the surface of the silicone rubber layer. Any known adhesive layer that can adhere to the surface of the silicone rubber layer can be used. A material in which these adhesive layers are provided on a flexible support is commercially available, for example, under the trade name “Scotch Tape # 851A” manufactured by Sumitomo 3M Limited.

  When lithographic printing plates that have been processed and made in this way are stacked and stored, it is preferable to insert and sandwich a slip sheet to protect the printing plate. The lithographic printing plate obtained by the plate making method is mounted on a printing machine, and a large number of excellent printed materials having excellent ink depositing properties in the image area can be obtained.

  The invention is explained in more detail by means of examples. However, the present invention is not limited to the following examples.

[Examples 1-39, Comparative Examples 1-4]
(Formation of back first layer)
The following coating solution was applied by a wire bar coating method onto a biaxially stretched polyethylene terephthalate film web-like support having a surface of 180 μm thickness subjected to a corona discharge treatment of 0.01 kW / m ² / min. A back first layer having a dry film thickness of 0.2 μm was formed by drying at 30 ° C. for 30 seconds.

<Back first layer coating solution>
・ Julimar ET-410
(Nippon Pure Chemicals Co., Ltd. acrylic resin aqueous dispersion, solid content 30% by mass) 1.9 parts by mass Conductive particles (tin oxide-antimony oxide aqueous dispersion,
9.1 parts by mass Denacol EX-614B (epoxy compound manufactured by Nagase ChemteX Corporation),
Active ingredient concentration: 100% by mass) 0.18 parts by mass • Sanded BL (manufactured by Sanyo Chemical Industries, Ltd., alkyl sulfonic acid sodium salt aqueous solution, 44% by mass) 0.14 parts by mass • Emarex 710 (Japan Emulsion Co., Ltd.) Manufactured polyoxyethylene alkyl ether, 100% by mass) 0.06 parts by mass • 89 parts by mass of distilled water

(Formation of back second layer)
The following coating solution was applied onto the back first layer by a wire bar coating method and dried at 170 ° C. for 30 seconds to form a back second layer having a dry film thickness of 0.07 μm.

<Back second layer coating solution>
Chemipearl S-120 (Mitsui Chemicals Co., Ltd. polyolefin latex, solid content 27% by mass) 1.6 parts by mass Snowtex C (Nissan Chemical Co., Ltd. colloidal silica, solid content 20% by mass) 1.1 Part by weight ・ Sanded BL (Sanyo Chemical Industries, Ltd., alkylsulfonic acid sodium salt aqueous solution, 44 mass%) 0.12 parts by mass ・ Emalex 710 (Nihon Emulsion Co., Ltd. polyoxyethylene alkyl ether, 100 mass%) 0.05 parts by mass-Denacol EX-614B (manufactured by Nagase ChemteX Corporation, epoxy compound, active ingredient concentration: 100% by mass) 0.15 parts by mass-Chemical Pearl W-950 (manufactured by Mitsui Chemicals, Inc., polyolefin matting agent, (Solid content 40% by mass) 0.04 parts by mass-97 parts by mass of distilled water

(Corona discharge treatment)
The opposite surface of the support provided with the back layer was subjected to corona discharge treatment at a treatment amount shown in Table 1 using a corona surface treatment machine R8-8 manufactured by KNI Power Systems, using air as the atmospheric gas. did. After winding up this support body, it was made to age with the period of Table 1 on condition of 25 degreeC50% RH.

(Formation of photothermal conversion layer)
The following mixture is stirred with a glass bead for 30 minutes in a paint shaker to disperse the carbon black, and after filtering the glass beads, 0.005 g of a surfactant KF333 (Dainippon Ink Chemical Co., Ltd.) is added. The mixture was stirred to prepare a photothermal conversion layer coating solution.
This coating solution was applied to the corona discharge treated surface of the support aged after the corona discharge treatment by a wire bar coating method so as to have a dry film thickness of 1.0 μm. This was heat-dried at 150 ° C. for 1 minute to form a photothermal conversion layer.

<Photothermal conversion layer coating solution>
Polyurethane (diphenylmethane diisocyanate: 5 mol, polypropylene glycol: 1 mol, 2,2′-dimethylolpropanoic acid: 4 mol reaction product) 3.0 parts by mass Carbon black listed in Table 1 Amount ・ Solsperse S24000R (manufactured by ICI) 0.15 mass parts ・ Solsperse S17000 (manufactured by ICI) 0.15 mass parts ・ Methyl ethyl ketone 29 mass parts ・ Propylene glycol monomethyl ether 15 mass parts

(Formation of silicone rubber layer)
The following coating solution was applied onto the photothermal exchange layer and dried by heating at 150 ° C. for 1 minute to form an addition type silicone rubber layer having a dry coating amount of 1.5 g / m ² .

<Silicone rubber layer coating solution>
・ FS-42 (Shin-Etsu Chemical Co., Ltd.,
α, ω-Divinylpolydimethylsiloxane, average degree of polymerization 1300) 9.0 parts by mass (CH ₃ ) ₃ SiO (SiH (CH ₃ ) O) ₈ -Si (CH ₃ ) ₃ 0.2 parts by mass Coordinate platinum catalyst 0.1 parts by mass Control agent [HC≡C—C (CH ₃ ) ₂ —O—Si (CH ₃ ) ₃ ] 0.2 part by mass • Isopar E (Exxon Chemical Co., Ltd.) 120. 0 parts by mass

  As described above, waterless planographic printing plate precursors used in Examples 1 to 39 and Comparative Examples 1 to 4 were obtained.

[Examples 40 to 62, Comparative Examples 5 to 8]
In the same manner as in Example 1, the back first layer and the back second layer were formed on the support.
(Formation of photothermal conversion layer)
The following mixture is stirred with a glass bead for 30 minutes in a paint shaker to disperse the carbon black, and after filtering the glass beads, 0.005 g of a surfactant KF333 (Dainippon Ink Chemical Co., Ltd.) is added. The mixture was stirred to prepare a photothermal conversion layer coating solution.
Corona discharge treatment was performed so that the O / C element ratio obtained by measuring this coating solution on the opposite surface of the support provided with the above-mentioned back layer by the method described later has the values shown in Table 2. After the application, it was applied by a wire bar coating method so as to have a dry film thickness of 1.0 μm. This was heat-dried at 150 ° C. for 1 minute to form a photothermal conversion layer.

<Photothermal conversion layer coating solution>
Polyurethane (diphenylmethane diisocyanate: 5 mol, polypropylene glycol: 1 mol, 2,2′-dimethylolpropanoic acid: 4 mol reaction product) 3.0 parts by mass Carbon black listed in Table 2 Amount ・ Solsperse S24000R (manufactured by ICI) 0.15 mass parts ・ Solsperse S17000 (manufactured by ICI) 0.15 mass parts ・ Methyl ethyl ketone 29 mass parts ・ Propylene glycol monomethyl ether 15 mass parts

  After the formation of the photothermal conversion layer, a silicone rubber layer was formed in the same manner as in Example 1, and waterless lithographic printing plate precursors used in Examples 40 to 62 and Comparative Examples 5 to 8 were obtained.

(Measurement of O / C element ratio of support surface after corona discharge treatment by ESCA)
Using an ESCA measuring apparatus of PHI-5400MC, X-ray source: Mg-Kα (400 W), path energy: 71.55 eV / 178.95 eV, analysis area: 1.1 mmφ, measurement mode: narrow scan (C1s, O1s, N1s ), Photoelectron take-off angle: measured at 20 °, and O / C element ratio was calculated from the element composition ratio. Each sample was measured three times and the average value was obtained.

<Carbon black (1)>
Raw material carbon black # 40 (manufactured by Mitsubishi Chemical Corporation) was charged in an amount corresponding to 1/10 of the column volume in a gas phase fluidized tank connected to an ozone generator, ozone flow rate was 2.0 Nm ³ / hr, ozone Oxidation treatment was performed under conditions of a concentration of 10 g / Nm ³ , a reaction time of 50 minutes, and room temperature to obtain an oxidized carbon black (1).

<Carbon black (2)>
Raw material carbon black # 40 (manufactured by Mitsubishi Chemical Co., Ltd.) is spread over a heat-resistant bat to a thickness of about 2 mm, placed in an electric furnace in an air atmosphere, and heated to 350 ° C. at a rate of 50 ° C./hr. The temperature was raised and held for 5 hours, and then naturally cooled to obtain oxidized carbon black (2).

<Carbon black (3)>
After mixing 10 g of raw material carbon black # 40 (manufactured by Mitsubishi Chemical Corporation) with 450 g of 30% by mass hydrogen peroxide solution, sulfuric acid was added to adjust the pH to 1, and the mixture was allowed to stand at room temperature for 12 hours. Filtration, washing with water and drying yielded an oxidized carbon black (3).

<Carbon black (4)>
Carbon black # 40 (manufactured by Mitsubishi Chemical Corporation) of raw material carbon black was mixed with 30 g of 60% by mass nitric acid aqueous solution and allowed to stand at room temperature for 48 hours, followed by filtration, washing with water, drying, and oxidation treatment. (4) was obtained.

<Carbon black (5)>
10g of raw material carbon black # 40 (Mitsubishi Chemical Corporation) was mixed with 250g of 4N sulfuric acid solution of potassium permanganate and allowed to stand at room temperature for 2 hours, then filtered, washed with water, dried and oxidized. Carbon black (5) was obtained.

[Evaluation of waterless planographic printing plate precursor]
(Scratch resistance model evaluation)
The obtained waterless lithographic printing plate precursor of the present invention was subjected to 175 lpi (1270 dpi) using a press setter PEARL setter (wavelength 830 nm, beam diameter 28 μm (1 / e ² ), mounted with a semiconductor laser having a maximum output of 750 mW). ) Dot image formation was performed. Thereafter, the plate surface was rubbed with a developing pad containing the treatment liquid 1 having the following composition to remove the silicone rubber layer in the laser irradiation portion. As a result, a waterless lithographic printing plate having a sharp-edged silicone image in which a dot area ratio of 2% to 98% was reproduced was formed.

<Processing liquid 1>
・ Polyoxyethylene sorbitan monooleate (Reodol TW-O106 manufactured by Kao Corporation) 5g
-Anti-scale agent BK2 (Fuji Photo Film Co., Ltd.) 2g
・ 993g of water

In order to evaluate the scratch resistance of these waterless lithographic printing plates, HEIDON-14 (surface property tester manufactured by Shinto Chemical Co., Ltd.) was used for the non-image part of the obtained waterless lithographic printing plate. A scratch test was conducted by changing the load on a 5-mmφ sapphire needle every 50 g from 50 to 500 g. Printing using the waterless planographic printing plate formed in this way (printing machine: Mitsubishi Heavy Industries, Ltd. Diamond 1F-2, ink: Toyo Ink Manufacturing Co., Ltd. Aqualess Echo New M ink, ink form roller Cooling: 20 ° C.), the printed matter after printing 500 sheets was observed for the presence or absence of smudges in the non-image area scratch portion, and the sapphire needle load at which ink smear began to occur was read and used as an index for this evaluation. The results are shown in Tables 3 and 4.

  As is apparent from Tables 3 and 4, the waterless lithographic printing plate precursors of the examples according to the present invention have good scratch resistance, and in particular, they were used in combination with a photothermal conversion layer containing oxidized carbon black. Examples 1 to 20, Examples 25 to 39, and Examples 46 to 62 have very good scratch resistance, but the waterless lithographic printing plate precursors of Comparative Examples 1 to 8 had unsatisfactory results. It was.

(Scratch resistance practical evaluation)
The obtained waterless lithographic printing plate precursor used in Examples and Comparative Examples of the present invention was processed into a roll form and mounted on a full color printing system machine “QuickmasterDI46-4pro” manufactured by Heidelberg. Subsequently, on this printing machine, exposure, removal of silicone residue from the exposed area, and printing (ink: Aqualess Echo New M ink manufactured by Toyo Ink Manufacturing Co., Ltd.) are performed, and a non-image is printed on the printed material after printing 20,000 sheets. As a result of evaluation of ink stains due to scratches on the surface, an average of 2 ink stains were generated per plate in the waterless lithographic printing plate of the comparative example, but ink stains were completely generated in the waterless lithographic printing plate of the examples. No good printed matter was obtained.

Claims (6)

A method for producing a dampening water-free lithographic printing plate precursor comprising at least a light-to-heat conversion layer and a silicone rubber layer sequentially laminated on a support, comprising 0.01 to 0.12 kW / m ² / min on the support A process for producing a lithographic printing plate precursor requiring no dampening water, wherein a photothermal conversion layer is directly provided on the corona discharge-treated surface after a lapse of 10 minutes to 1 month after the corona discharge treatment.   The method for producing a dampening-free lithographic printing plate precursor according to claim 1, wherein the support is a biaxially stretched polyethylene terephthalate. The method for producing a dampening-free lithographic printing plate precursor according to claim 1 or 2, wherein the corona discharge treatment amount is 0.06 to 0.09 kW / m ² / min.   A dampening-free lithographic printing plate precursor in which at least a photothermal conversion layer and a silicone rubber layer are sequentially laminated on a polyethylene terephthalate support, and the surface oxygen of the support measured by X-ray photoelectron spectroscopy (ESCA) A dampening-free lithographic printing plate comprising a photothermal conversion layer directly provided on the corona discharge-treated surface after the support surface is subjected to a corona discharge treatment so that the carbon element ratio is 0.41 or more. Original edition.   The method for producing a dampening-free lithographic printing plate precursor as claimed in any one of claims 1 to 4, wherein the photothermal conversion layer contains oxidized carbon black.   The lithographic printing plate precursor requiring no fountain solution according to claim 5, wherein the content of oxidized carbon black in the photothermal conversion layer is 35% by mass or more based on the total solid content of the photothermal conversion layer. Manufacturing method.