JP2009080479A - Waterless lithographic printing plate precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waterless lithographic printing plate precursor with which plate inspection can be done without a dyeing process. <P>SOLUTION: The waterless lithographic printing plate precursor has at least a photosensitive layer or a heat sensitive layer and a silicone rubber layer on a substrate, wherein the center average roughness (Ra) of the surface of the silicone rubber layer is 1 to 100 nm, preferably 5 to 50 nm. Moreover, it is preferable to roughen the silicone rubber layer surface by a dry etching process, thereby performing plate inspection without a dyeing process. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a waterless lithographic printing plate precursor.

  Conventionally, various printing plates have been proposed for performing lithographic printing (hereinafter referred to as waterless lithographic printing) using silicone rubber or fluororesin as an ink repellent layer without using dampening water.

  Waterless lithographic printing uses the difference in ink adhesion, with the image area and non-image area present on the same plane, with the image area as the ink receiving layer and the non-image area as the ink repellent layer. This is a lithographic printing method in which ink is applied only to an image area and then transferred to a printing medium such as paper, and printing is performed without using dampening water.

  Various exposure methods for waterless lithographic printing plate precursors have been proposed, including a method of irradiating ultraviolet rays through an original film, and a computer-to-plate (CTP) that writes an image directly from an original without using the original film. ) The method is roughly divided, and by using recent digital technology, light with high directivity such as laser light is scanned on the plate surface according to the digitized image information, so that the plate surface is exposed directly without going through the lith film. The CTP method for processing has become mainstream.

  The waterless lithographic printing plate precursor includes a photosensitive (thermal) layer removing type in which a photosensitive (thermal) layer is removed in an exposure process or a developing process, and a photosensitive (thermal) layer remaining even after an exposure process and a developing process ( Heat) layer residual type. The photosensitive (thermal) layer removal type removes the photosensitive (thermal) layer, so it is possible to add color contrast between the image area and non-image area by including a colored dye in the photosensitive (thermal) layer. is there. For this reason, it has the merit that plate inspection can be performed without a post-staining step. However, since the depth of the cell forming the image area is deep, a large amount of ink is required at the time of printing. In addition, since it is necessary to remove the photosensitive (thermal) layer in the depth direction, there is a problem that it is difficult to reproduce a fine image.

  On the other hand, a heat-sensitive layer-remaining waterless CTP lithographic printing plate precursor having at least a heat-sensitive layer and a silicone rubber layer on a substrate has been proposed (see, for example, Patent Documents 1 and 2). In these printing plate precursors, the heat-sensitive layer in the laser-irradiated portion remains even after development, so that the amount of ink used during printing is small and fine image reproducibility is also good. In addition, since exposure can be performed with a low laser output, not only is it advantageous in terms of running cost and laser life, but ablation debris is not generated during laser irradiation, and a special suction device is not required. However, since the heat-sensitive layer remains in both the laser irradiation part and the non-irradiation part, it is difficult to obtain color contrast between the laser irradiation part and the non-irradiation part, and plate inspection is difficult.

  In a method for producing a lithographic printing plate using a heat-sensitive layer-remaining waterless CTP lithographic printing plate precursor, a method having a step of dyeing a plate has been proposed (for example, see Patent Document 3). This method makes it possible to inspect the printing plate after dyeing the image area, but it requires an extra dyeing process, so there are problems in terms of management of the dye solution, enlargement of the developing machine, cost, etc. . Moreover, the thing (for example, patent document 4, 5) which used the dyeing | staining process and roughened the aluminum substrate also had the same subject.

In contrast, a waterless lithographic printing plate precursor containing a photobleachable substance or a photochromic substance in the silicone rubber layer (see, for example, Patent Document 6), and a waterless CTP lithographic plate containing a dye in the silicone rubber layer A printing plate precursor (see, for example, Patent Document 7) has been proposed. These printing plate precursors can be inspected without a post-dyeing step. However, those containing a photobleachable substance or a photochromic substance have a problem that cannot be handled in a bright room. In addition, when the dye contains a dye, the dye in the silicone rubber layer aggregates in the layer over time, the dye concentrates on the more polar heat-sensitive layer interface, or has a protective film on the silicone rubber layer. Has a problem in dye fixing property in the silicone rubber layer, such as adsorption of a dye to the protective film. For this reason, there are cases where the plate inspection property is lowered and the adhesive force between the silicone rubber layer / the heat-sensitive layer is lowered due to dye concentration. In addition, colored dyes may be extracted with various organic chemicals used during development or solvents in inks used during printing, resulting in deterioration of plate inspection and contamination of developer chemicals and ink by the extracted dyes. There was a case.
JP-A-11-227355 (Claims) Japanese Patent Laying-Open No. 2005-300586 (Claims) JP-A-11-227353 (Claims) JP 2001-130155 A (Claims) JP 2003-266966 A (Claims) JP-A-9-189993 (Claims) JP 2002-244279 A (Claims)

  An object of the present invention is to provide a waterless planographic printing plate precursor that can be inspected without requiring a dyeing step.

  The present invention is a waterless lithographic printing plate precursor having at least a photosensitive layer or a heat-sensitive layer and a silicone rubber layer on a substrate, wherein the center average roughness (Ra) of the surface of the silicone rubber layer is from 1 nm to 100 nm. It is a waterless lithographic printing plate precursor characterized by being.

  According to the present invention, a waterless lithographic printing plate precursor that can be inspected without requiring a dyeing step is obtained.

The present invention is described in detail below.

  The silicone rubber layer used in the present invention may be either an addition reaction type or a condensation reaction type.

  The addition reaction type silicone rubber layer is formed from a composition (hereinafter referred to as a silicone liquid) containing at least a vinyl group-containing organopolysiloxane, a SiH group-containing compound (addition reaction type crosslinking agent), a reaction inhibitor and a curing catalyst. .

The vinyl group-containing organopolysiloxane has a structure represented by the following general formula (I) and has a vinyl group at the end of the main chain or in the main chain. Of these, those having a vinyl group at the end of the main chain are preferred.
-(SiR ¹ R ² -O-) _n- (I)
In the formula, n represents an integer of 2 or more, and R ¹ and R ² may be the same or different and each represents a saturated or unsaturated hydrocarbon group having 1 to 50 carbon atoms. The hydrocarbon group may be linear, branched or cyclic and may contain an aromatic ring.

In the above formula, 50% or more of R ¹ and R ² are preferably methyl groups from the viewpoint of ink repellency of the printing plate. Further, from the viewpoints of handleability, ink repellency of the printing plate, and scratch resistance, the weight average molecular weight of the vinyl group-containing organopolysiloxane is preferably 10,000 to 600,000.

Examples of the SiH group-containing compound include organohydrogenpolysiloxanes and organic polymers having diorganohydrogensilyl groups, and organohydrogensiloxanes are preferred. Organohydrogen has a linear, cyclic, branched, and network molecular structure, both ends of the molecular chain trimethylsiloxy group-blocked polymethylhydrogensiloxane, molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane and methylhydrogensiloxane Copolymer, Trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer, both ends of the molecular chain dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, dimethylhydrogensiloxy group at both ends of the molecular chain Blocked dimethylsiloxane / methylphenylsiloxane copolymer, dimethylhydrogensiloxy group-blocked methylphenylpolysiloxane at both molecular chain ends, siloxane unit represented by formula: R ₃ SiO _1/2 and formula: R ₂ Organopolysiloxane copolymer comprising a siloxane unit represented by HSiO _1/2 and a siloxane unit represented by formula: SiO _4/2 , a siloxane unit represented by formula: R ₂ HSiO _1/2 and formula: SiO _4/2 An siloxane unit represented by formula: RHSiO _2/2 and a siloxane unit represented by formula: RSiO _3/2 or a siloxane unit represented by formula: HSiO _3/2 And an organopolysiloxane copolymer. Two or more of these organopolysiloxanes may be used. In the above formula, R is a monovalent hydrocarbon group other than an alkenyl group, and is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group; a phenyl group, a tolyl group, a xylyl group And aryl groups such as naphthyl group; aralkyl groups such as benzyl group and phenethyl group; and halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group and 3,3,3-trifluoropropyl group.

  Examples of the organic polymer having a diorganohydrogensilyl group include dimethylhydrogensilyl group-containing acrylic monomers such as dimethylhydrogensilyl (meth) acrylate and dimethylhydrogensilylpropyl (meth) acrylate, and (meth) acrylic. Monomers such as methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ethyl hexyl (meth) acrylate, lauryl (meth) acrylate, styrene, α-methylstyrene, maleic acid, vinyl acetate, allyl acetate And an oligomer obtained by copolymerization.

  The content of the SiH group-containing compound is preferably 0.5% by weight or more, more preferably 1% by weight or more in the silicone liquid from the viewpoint of curability of the silicone rubber layer. Moreover, 20 weight% or less is preferable and 15 weight% or less is more preferable.

  Examples of the reaction inhibitor include nitrogen-containing compounds, phosphorus compounds, unsaturated alcohols, and the like, and acetylene group-containing alcohols are preferably used. By containing these reaction inhibitors, the curing rate of the silicone rubber layer can be adjusted. The content of the reaction inhibitor is preferably 0.01% by weight or more, more preferably 0.1% by weight or more in the silicone liquid from the viewpoint of the stability of the silicone liquid. Further, from the viewpoint of curability of the silicone rubber layer, it is preferably 20% by weight or less, more preferably 15% by weight or less in the silicone liquid.

  The curing catalyst is selected from known ones, but is preferably a platinum-based compound. Specifically, platinum alone, platinum chloride, chloroplatinic acid, olefin coordinated platinum, platinum alcohol-modified complex, platinum methylvinylpolysiloxane A complex etc. can be mentioned as an example. From the viewpoint of curability of the silicone rubber layer, the content of the curing catalyst is preferably 0.001% by weight or more, and more preferably 0.01% by weight or more in the silicone liquid. Further, from the viewpoint of the stability of the silicone liquid, it is preferably 20% by weight or less, and more preferably 15% by weight or less.

  In addition to these components, hydroxyl group-containing organopolysiloxane, hydrolyzable functional group-containing silane (or siloxane), known fillers such as silica for the purpose of improving rubber strength, and known for the purpose of improving adhesiveness. The silane coupling agent may be contained. As the silane coupling agent, alkoxysilanes, acetoxysilanes, ketoximinosilanes and the like are preferable, and those having a vinyl group or an allyl group are particularly preferable.

  The condensation reaction type silicone rubber layer comprises at least a hydroxyl group-containing organopolysiloxane, a crosslinking agent (deacetic acid type, deoxime type, dealcohol type, deamine type, deacetone type, deamid type, deaminoxy type, etc.), and It is formed from a composition (silicone liquid) containing a curing catalyst.

  The hydroxyl group-containing organopolysiloxane has a structure represented by the general formula (I) and has a hydroxyl group at the end of the main chain or in the main chain. Of these, those having a hydroxyl group at the end of the main chain are preferred.

In terms of ink repellency of the printing plate, R ¹ and R ² in the general formula (I) are preferably 50% or more of methyl groups. The weight average molecular weight of the hydroxyl group-containing organopolysiloxane is preferably 10,000 to 600,000 from the viewpoints of handling properties, ink repellency of the printing plate, and scratch resistance.

Examples of the crosslinking agent used in the condensation reaction type silicone rubber layer include acetoxysilanes, alkoxysilanes, ketoximinosilanes, and allyloxysilanes represented by the following general formula (II).
(R ³ ) _4-n SiX _n (II)
In the formula, n represents an integer of 2 to 4, R ³ may be the same or different, and represents a substituted or unsubstituted alkyl group, alkenyl group, aryl group, or a combination thereof having 1 or more carbon atoms. Show. X may be the same or different and is a halogen atom, an alkoxy group, an acyloxy group, a ketoximino group, an aminooxy group, an amide group or an alkenyloxy group. In the above formula, the number n of hydrolyzable groups is preferably 3 or 4.

  Specific compounds include methyltriacetoxysilane, ethyltriacetoxysilane, vinyltriacetoxysilane, allyltriacetoxysilane, acetoxysilanes such as phenyltriacetoxysilane, tetraacetoxysilane, and vinylmethylbis (methylethylketoximino) silane. , Methyltris (methylethylketoximino) silane, ethyltris (methylethylketoximino) silane, vinyltris (methylethylketoximino) silane, allyltris (methylethylketoximino) silane, phenyltris (methylethylketoximino) silane, tetrakis (methylethylketoximino) silane, etc. Ketoximinosilanes, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltrie Alkoxysilanes such as xyloxysilane, tetraethoxysilane, tetrapropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltriethoxysilane, vinyltriisopropoxysilane, vinyltrisisopropenoxysilane, diisopropenoxydimethylsilane, Examples thereof include, but are not limited to, alkenyloxysilanes such as triisopropenoxymethylsilane and tetraallyloxysilane. Among these, acetoxysilanes and ketoximinosilanes are preferable from the viewpoint of the curing speed of the silicone rubber layer, handling properties, and the like.

  The content of the crosslinking agent is preferably 0.5% by weight or more, more preferably 1% by weight or more in the silicone liquid, from the viewpoint of the stability of the silicone liquid. Further, from the viewpoint of the strength of the silicone rubber layer and the scratch resistance of the printing plate, it is preferably 20% by weight or less, more preferably 15% by weight or less in the silicone liquid.

  Curing catalysts include organic carboxylic acids such as acetic acid, propionic acid and maleic acid, acids such as toluenesulfonic acid and boric acid, alkalis such as potassium hydroxide, sodium hydroxide and lithium hydroxide, amines, and titanium tetrapropoxide. Metal alkoxides such as titanium tetrabutoxide, metal diketenates such as iron acetylacetonate and titanium acetylacetonate dipropoxide, and metal organic acid salts. Among these, metal organic acid salts are preferable, and metal organic acid salts selected from tin, lead, zinc, iron, cobalt, calcium, and manganese are particularly preferable. Specific examples of such compounds include dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, zinc octylate, and iron octylate. The content of the curing catalyst is preferably 0.001% by weight or more, more preferably 0.01% by weight or more in the silicone liquid from the viewpoint of curability and adhesiveness of the silicone rubber layer. Further, from the viewpoint of the stability of the silicone liquid, it is preferably 15% by weight or less in the silicone liquid, and more preferably 10% by weight or less.

  In addition to these components, a known filler such as silica and further a known silane coupling agent may be contained for the purpose of improving rubber strength.

  As a result of intensive investigations to enable plate inspection without requiring a dyeing step, the present inventors have found that the surface roughness of the silicone rubber layer is related. The greatest feature of the present invention is that the surface roughness of the silicone rubber layer is such that the center line average roughness (Ra) is from 1 nm to 100 nm, and preferably from 5 nm to 50 nm. When the center line average roughness Ra is less than 1 nm, the surface is not sufficiently roughened, and the visibility is poor, so that no effect is obtained on the plate inspection. On the other hand, if it is larger than 100 nm, the visibility is sufficient, but the roughening causes the ink repellency of the silicone rubber layer to decrease, and scumming occurs during printing. That is, by adjusting the roughness of the surface of the silicone rubber layer between the center line average roughness (Ra) of 1 nm or more and 100 nm or less, a waterless lithographic printing plate precursor that enables plate inspection without requiring a dyeing step Can be obtained.

  Here, a method for measuring the centerline average roughness (Ra) will be described. In the present invention, the center line average roughness (Ra) of the silicone rubber layer surface is based on the definition of the surface roughness in JIS B0601 Appendix 2 (2001), and specifically, the surface shape measurement that is commercially available. It can be measured using a machine, a stylus meter or the like.

  By roughening the surface of the silicone rubber layer, a silicone rubber layer having a center line average roughness (Ra) in the above range can be produced.

As means for controlling the center line average roughness (Ra) of the silicone rubber layer surface, conventionally known roughening treatments such as mechanical roughening, chemical roughening, and electrochemical roughening are available. Can be mentioned. In particular, a dry etching process that is a chemical roughening process is preferably used in the present invention. Dry etching is a method of etching a material with a reactive gas (etching gas), ions, or radicals. A feature is that fine processing is possible without requiring cleaning as a post-process. Examples of dry etching include reactive gas etching in which a material is exposed to a reactive gas and reactive ion etching in which gas is ionized and radicalized by plasma to perform etching. Reactive ion etching is a method in which sputtering with ions and a chemical reaction of an etching gas occur at the same time, and etching with high accuracy suitable for microfabrication can be performed. In particular, reactive ion etching such as sputter etching or reactive ion etching is preferably used in the present invention. Sputter etching is a gas composed of only a component that does not substantially react with an insulating film material such as a noble gas that is a group 18 gas in the periodic table of elements such as He, Ne, Ar, Kr, Xe, and Rn, or nitrogen gas. Etching is performed using The reactive ion etching is an etching method that uses a fluorocarbon-based etching gas such as a gas containing CH ₂ F ₂ or CHF ₃ .

  In order to perform the etching process, a conventionally known etching apparatus can be used. By adjusting conditions such as power, time, and pressure during etching, the surface of the silicone rubber layer has a center line average roughness of 1 to 100 nm. (Ra).

In the waterless lithographic printing plate precursor according to the invention, the thickness of the silicone rubber layer is preferably 0.5 to 20 g / m ² . Film thickness printing plate ink repellency and scratch resistance by a 0.5 g / m ² or more, the printing durability becomes sufficient, not disadvantageous from an economic point of view by a 20 g / m ² or less, developing The ink mileage is less likely to deteriorate.

  As the photosensitive (thermal) layer used in the present invention, any type of photosensitive (thermal) layer that has been proposed as a photosensitive (thermal) layer for waterless lithographic printing plate can be used. It is. Hereinafter, although a specific example is given and demonstrated, it is not limited to these.

(Heat-sensitive layer-1) Heat-sensitive layer for negative-type waterless CTP lithographic printing plate precursor Examples include the heat-sensitive layer described in JP-A-11-221977. In the raw plate state, a crosslinked structure is formed by a crosslinking agent, and the heat-sensitive layer is a type in which the adhesive force between the heat-sensitive layer and the silicone rubber layer is reduced by heat generated by irradiation with a near-infrared laser. Subsequent development processing removes the silicone rubber layer in the portion irradiated with the laser beam. The heat-sensitive layer in the laser irradiation part remains even after development.

(Heat-sensitive layer-2) Heat-sensitive layer for negative-type waterless CTP lithographic printing plate precursor Examples include a heat-sensitive layer containing bubbles described in JP-A-2005-300586. In the raw plate state, a crosslinked structure is formed by a crosslinking agent, and the heat-sensitive layer is a type in which the adhesive force between the heat-sensitive layer and the silicone rubber layer is reduced by heat generated by irradiation with a near-infrared laser. Subsequent development processing removes the silicone rubber layer in the portion irradiated with the laser beam. The heat-sensitive layer in the laser irradiation part remains even after development.

(Heat-sensitive layer-3) Heat-sensitive layer for negative-type waterless CTP lithographic printing plate precursor Examples include the heat-sensitive layer described in JP-A-9-131981. It is a type of heat-sensitive layer that is destroyed by heat generated by irradiation with a near-infrared laser. Then, by removing this portion by development, the silicone rubber layer on the surface is removed together with the destroyed heat-sensitive layer to form an image area. In general, such a heat-sensitive layer is used after completely destroying the heat-sensitive layer in the depth direction from the viewpoint of plate inspection. However, in order to completely destroy the heat-sensitive layer, high-energy laser irradiation is necessary, which causes various adverse effects such as poor reproducibility of fine images, optical system contamination due to ablation, and reduction in laser life. When the laser energy is lowered, there appears an area where the upper silicone rubber layer can be removed while most of the heat sensitive layer remains. Plate inspection is difficult because most of the thermosensitive layer remains, but adverse effects other than plate inspection are greatly suppressed. When the colored pigment-containing silicone rubber layer of the present invention is provided, plate inspection is possible even if most of the heat-sensitive layer remains.

(Heat-sensitive layer-4) Heat-sensitive layer for negative-type waterless CTP lithographic printing plate precursor For example, metals described in JP-A-7-314934 and JP-A-9-086065, or oxides, carbides and nitrides thereof. , Boride, fluoride thin films, and the like. The metal thin film is destroyed by the heat generated by the near infrared laser irradiation. Then, by removing this portion by development, the silicone rubber layer on the surface is peeled off at the same time to form an image portion. Similar to the thermosensitive layer-3, such a metal thin film is generally used after being completely laser-destructed in the depth direction from the viewpoint of plate inspection. However, in order to completely destroy the metal thin film, high-energy laser irradiation is required, and this causes various adverse effects such as poor reproducibility of fine images, optical system contamination due to ablation debris, and a reduction in laser life. When the laser energy is lowered, there appears an area where the upper silicone rubber layer can be removed while most of the metal thin film remains. Plate inspection is difficult because most of the metal thin film remains, but adverse effects other than plate inspection are greatly suppressed. When the colored pigment-containing silicone rubber layer of the present invention is provided, plate inspection is possible even if most of the metal thin film remains.

(Thermosensitive layer-5) Thermosensitive layer for positive-type waterless CTP lithographic printing plate precursor Examples of the thermosensitive thermosensitive layer described in JP-A-11-157236 and JP-A-11-240271 can be given. . It is a type of heat-sensitive layer in which a cross-linked structure is formed by a heat-activated cross-linking agent by heat generated by irradiation with a near infrared laser. Subsequent development processing leaves a portion of the silicone rubber layer that has been irradiated with laser light, and removes the portion of the silicone rubber layer that has not been irradiated. The heat-sensitive layer in the unirradiated portion of the laser remains even after development.

(Photosensitive layer-1) Photosensitive layer for negative-type waterless lithographic printing plate precursor Examples include the photosensitive layer described in JP-A No. 11-352672. By increasing the solubility of the surface of the photosensitive layer in the pretreatment liquid by irradiation with ultraviolet rays, the silicone rubber layer in the portion irradiated with ultraviolet rays is removed by the development treatment, and the silicone rubber layer in the unirradiated portion remains. The photosensitive layer in the exposed area remains after development.

(Photosensitive layer-2) Photosensitive layer for a positive type waterless lithographic printing plate precursor, for example, a photosensitive layer described in JP-A-6-118629. Polymerization of the ethylenically unsaturated double bond-containing compound occurs due to radicals generated by the irradiation of ultraviolet rays, and the silicone rubber layer in the portion irradiated with ultraviolet rays remains by the development treatment, and the silicone rubber layer in the unirradiated portion is removed. . The unexposed photosensitive layer remains even after development.

  As the substrate used in the present invention, known dimensionally stable paper, metal, film and the like conventionally used as a substrate of a printing plate can be used. Specifically, paper, paper laminated with plastic (polyethylene, polypropylene, polystyrene, etc.), aluminum (including aluminum alloy), zinc, copper and other metal plates, cellulose acetate, polyethylene terephthalate, polyethylene, polyester, polyamide, Examples thereof include a plastic film such as polyimide, polystyrene, polypropylene, polycarbonate, and polyvinyl acetal, and a paper or plastic film on which a metal as described above is laminated or vapor-deposited. The plastic film can be either transparent or opaque. Among these, the use of an opaque film is preferable from the viewpoint of plate inspection.

  Of these substrates, an aluminum plate is particularly preferred because it is extremely dimensionally stable and inexpensive. A polyethylene terephthalate film is particularly preferable as a flexible substrate for light printing.

  A primer layer may be provided on the above-mentioned substrate for the purpose of improving adhesion between the substrate and the photosensitive layer, preventing light halation, improving plate inspection, improving heat insulation, and improving printing durability. As a primer layer used for this invention, the primer layer described in Unexamined-Japanese-Patent No. 2004-199016 etc. can be mentioned, for example.

  The waterless lithographic printing plate precursor configured as described above may have a protective film or a slip sheet for the purpose of protecting the silicone rubber layer. Either the protective film or the slip sheet may be used alone, or both may be used in combination.

  The protective film is preferably a film having a thickness of 100 μm or less that transmits light of the exposure light source wavelength satisfactorily. Typical examples include polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, cellophane, and the like. Further, for the purpose of preventing exposure of the original plate due to exposure, various kinds of light absorbers, photobleachable substances and photochromic substances as described in JP-A-2-063050 may be provided on the protective film. Good. In the case of exposure using the original image film, from the viewpoint of improving the adhesion to the original image film, an uneven processed protective film as described in JP-A-55-55343 and JP-A-2-063051 is used. It is preferable to use it.

The slip sheet is preferably one weighing 30 to 120 g / ^{m 2,} more preferably from 30~90g / ^{m 2.} If the weight is 30 g / m ² or more, the mechanical strength is sufficient, and if it is 120 g / m ² or less, not only is it economically advantageous, but the water-less lithographic printing plate precursor and paper laminate become thin, Workability becomes advantageous. Examples of interleaving paper preferably used include, for example, information recording base paper 40 g / m ² (manufactured by Nagoya Pulp Co., Ltd.), metal interleaving paper 30 g / m ² (manufactured by Nagoya Pulp Co., Ltd.), unbleached kraft paper 50 g / m. ² (manufactured by Chuetsu Pulp Industries Co., Ltd.), NIP paper 52 g / m ² (manufactured by Chuetsu Pulp Industries Co., Ltd.), pure white roll paper 45 g / m ² (Oji Paper Co., Ltd.), Kurpac 73 g / m ² (Oji Paper Co., Ltd.) However, it is not limited to these.

  Next, a method for producing a waterless lithographic printing plate precursor according to the present invention will be described. A primer solution or a primer diluted solution obtained by diluting it with a solvent is applied to a substrate having a coated surface degreased as necessary to provide a primer layer. You may heat-process for drying and hardening. Thereafter, a waterless lithographic printing plate precursor can be obtained by sequentially providing a photosensitive (thermal) layer and a silicone rubber layer in the same manner as the primer layer. The application method of each liquid is slit die coater, direct gravure coater, offset gravure coater, reverse roll coater, natural roll coater, air knife coater, roll blade coater, varibar roll blade coater, two stream coater, rod coater, wire. A coating method using a bar coater, dip coater, curtain coater, spin coater or the like is used. A common heating device such as a hot air dryer or an infrared dryer is used for heating each layer.

  Further, by using the obtained waterless lithographic printing plate precursor, the surface of the silicone rubber layer is subjected to surface roughening treatment such as mechanical surface roughening and electrochemical surface roughening, whereby the waterless lithographic printing of the present invention is performed. A plate original is obtained. From the viewpoint of protecting the plate surface, it is preferable to store the silicone rubber layer with either a protective film or a slip sheet, or both.

  The waterless lithographic printing plate precursor thus obtained is exposed imagewise on a protective film or after peeling off the protective film and then exposed through an image film or by laser scanning exposure using digital data. Examples of exposure light sources include carbon arc lamps, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, metal halide lamps, fluorescent lamps, tungsten lamps, halogen lamps, ultraviolet lasers, visible light lasers, and (near) infrared light. A laser etc. are mentioned.

  The exposed original plate is developed by a friction treatment in the presence or absence of a developer. The rubbing treatment can be performed by rubbing the plate surface with a nonwoven fabric, absorbent cotton, cloth, sponge, brush or the like, or by wiping the plate surface with a nonwoven fabric, absorbent cotton, cloth, sponge, etc. impregnated with a developer. Alternatively, the plate surface can be pretreated with a developer and then rubbed with a rotating brush while showering tap water or the like, or high-pressure water, hot water, or steam can be sprayed onto the plate surface.

  Prior to development, a pretreatment in which a plate is immersed in a pretreatment solution for a certain time may be performed. As the pretreatment liquid, for example, water or water added with a polar solvent such as alcohol, ketone, ester or carboxylic acid, polar solvent such as aliphatic hydrocarbons, aromatic hydrocarbons, etc. A solvent added or a polar solvent is used. In addition, a known surfactant can be freely added to the developer composition. As the surfactant, those having a pH of 5 to 8 when made into an aqueous solution are preferable from the viewpoints of safety, cost for disposal, and the like. The content of the surfactant is preferably 10% by weight or less of the developer. Such a developer has high safety and is preferable from the viewpoint of economy such as disposal cost. Furthermore, it is preferable to use a glycol compound or glycol ether compound as a main component, and it is more preferable that an amine compound coexists.

  The pretreatment liquid and the developer are described in JP-A-63-179361, JP-A-4-163557, JP-A-4-343360, JP-A-9-34132, and JP3716429. For example, those disclosed for the pretreatment liquid and developer of the waterless lithographic printing plate precursor can be used. Specific examples of the pretreatment liquid include PP-1, PP-3, PP-F, PP-FII, PTS-1, PH-7N, CP-1, NP-1, DP-1 (all of which are Toray Industries, Inc. ) Made).

  The development processing can be automatically performed by an automatic developing machine. As an automatic processor, a device having only a developing unit, a preprocessing unit, a device in which a developing unit is provided in this order, a preprocessing unit, a developing unit, a device in which a post-processing unit is provided in this order, a preprocessing unit, a developing unit, The apparatus etc. in which the post-processing part and the water washing part were provided in this order can be used. Specific examples of such an automatic developing machine include TWL-650 series, TWL-860 series, TWL-1160 series (both manufactured by Toray Industries, Inc.), and the like, JP-A-4-2265, and JP-A-5-2272. And automatic developing machines disclosed in Japanese Patent Laid-Open No. 5-6000 and the like, and these can be used alone or in combination.

  In the case where the developed printing plates are stacked and stored, it is preferable to sandwich a slip sheet between the plates for the purpose of protecting the printing plate.

  The present invention will be described in more detail with reference to examples.

<Center average roughness (Ra) of the silicone rubber layer surface>
The silicone rubber surface of the obtained waterless lithographic printing plate was observed under the following conditions using an AFM measuring apparatus Nanoscope (manufactured by Digital Instruments), and the center average roughness (Ra) of the silicone rubber layer surface was measured.
Integral Gain: 2.1
Proportional Gain: 2.5
Amplitude Setpoint: 0.65
Scan Size: 10 μm

<Evaluation of plate inspection>
1-99% of the halftone dots (175 lpi) of the obtained waterless lithographic printing plate were observed with a magnifying glass (× 50) and evaluated according to the following criteria.
A: There is sufficient color contrast between the image area / non-image area, and loupe observation of halftone dots (1 to 99%) is possible.
Δ: There is color contrast between the image area / non-image area, and loupe observation of halftone dots (3-97%) is possible.
×: There is no color contrast between the image area / non-image area, and loupe observation of halftone dots is impossible.

<Evaluation of dot area ratio>
The dot area ratio of each dot (175 lpi) of 5%, 20%, 35%, 50%, 65%, 80%, and 95% on the waterless lithographic printing plate obtained by exposure and development Area ratio measuring device: Measured by “ccDot” type 4 (manufactured by Center Fax). More specifically, the measurement color (one of yellow, red, or indigo) is selected, and the 50% halftone dot area ratio on the waterless planographic printing plate obtained by exposure and development is measured three times, and then 5 %, 20%, 35%, 50%, 65%, 80%, 95%, each halftone dot area ratio was measured three times, and the average value was defined as the halftone dot area ratio (average Rounded to the first decimal place. The waterless lithographic printing plate precursor of the present invention has a roughened surface of the uppermost silicone rubber layer, and the waterless lithographic printing plate after exposure and development becomes a negative image (non-image area: dark color, Image area: pale color). From this, the dot area ratio measurement was performed in the negative (display on the apparatus:-(minus)) mode. The measurement results were evaluated according to the following criteria.
○: The difference in the amount of reflected light between the image area / non-image area is large and accurate reading is possible. Δ: The difference in the amount of reflected light between the image area / non-image area is slightly small. : The difference in the amount of reflected light between the image area / non-image area is small and cannot be read at all.

<Printing evaluation (background stain evaluation)>
The obtained waterless lithographic printing plate is attached to an offset printing machine (Komori Sprint 4-color machine) and 100 sheets of high-quality paper using “Dryo Color” (Dainippon Ink and Chemicals) black ink. Printing was done. The obtained printed matter was confirmed with a magnifying glass (× 50), and it was confirmed that the ink adhered to the silicone rubber layer in the non-image area, and the printing paper surface was not stained.

<Preparation of titanium oxide dispersion>
In 10 parts by weight of N, N-dimethylformamide, 10 parts by weight of titanium oxide “CR-50” (manufactured by Ishihara Sangyo Co., Ltd.) was added and stirred for 5 minutes. Further, 15 parts by weight of glass beads (No. 08) were added, and the mixture was vigorously stirred for 20 minutes. Thereafter, the glass beads were removed to obtain a titanium oxide dispersion (concentration: 50%).

<Composition of primer layer solution>
(1) Epoxy resin: Epicoat (registered trademark) 1010 (manufactured by Japan Epoxy Resin Co., Ltd.): 49 parts by weight (2) Polyurethane resin: Samprene (registered trademark) LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd., concentration 20) %, N, N-dimethylformamide / 2-ethoxyethanol solution): 98 parts by weight (3) Aluminum tris (ethyl acetoacetate): “aluminum chelate” ALCH-TR (manufactured by Kawaken Fine Chemical Co., Ltd.): 11.2 Weight part (4) Vinyl polymer: Disparon (registered trademark) LC951 (manufactured by Enomoto Kasei Co., Ltd.): 0.2 part by weight (5) Titanium oxide dispersion (concentration 50%): 84 parts by weight (titanium oxide: 42 parts by weight)
(6) N, N-dimethylformamide: 302.5 parts by weight (7) Methyl ethyl ketone: 315.6 parts by weight.

<Composition of heat-sensitive layer solution>
(1) Infrared absorbing dye: “PROJET” 825LDI (manufactured by Avecia Co., Ltd.): 16 parts by weight (2) Titanium di-n-butoxide bis (2,4-pentanedionate): NACEM (registered trademark) titanium (Nippon Chemical Industries) (Made by Co., Ltd., titanium concentration: about 8.8%, n-butanol solution): 37.5 parts by weight (3) phenol novolac resin: Sumilite Resin (registered trademark) PR53195 (manufactured by Sumitomo Durez Co., Ltd.): 60 weights Part (4) Polyurethane resin: Samprene (registered trademark) LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd., concentration 20%, N, N-dimethylformamide / 2-ethoxyethanol solution): 125 parts by weight (polyurethane resin: 25 Parts by weight)
(5) 3-glycidoxypropyltrimethoxysilane: 15 parts by weight (6) Tetrahydrofuran: 993 parts by weight (7) Ethanol: 64 parts by weight

<Composition of silicone rubber layer solution>
(1) α, ω-divinylpolydimethylsiloxane DMS-V42 (weight average molecular weight 72,000, manufactured by GELEST Inc.): 100 parts by weight (2) Both end methyl (methylhydrogensiloxane) (dimethylsiloxane) copolymer , SiH group-containing polysiloxane HMS-071 (manufactured by GELEST Inc.): 4 parts by weight (3) vinyltri (methylethylketoximine) silane: 3 parts by weight (4) platinum catalyst: “SRX-212” (Toray Dow Corning Silicone ( Co., Ltd.): 10 parts by weight.

Example 1
The primer layer solution was applied on a degreased aluminum substrate (manufactured by Mitsubishi Aluminum Co., Ltd.) having a thickness of 0.225 mm and dried at 200 ° C. for 1 minute to provide a primer layer having a thickness of 10 g / m ² . The thermosensitive layer solution was applied on the primer layer and dried at 150 ° C. for 80 seconds to provide a thermosensitive layer having a thickness of 1.5 g / m ² . On the heat-sensitive layer, the silicone rubber solution was applied and dried at 125 ° C. for 80 seconds to provide a silicone rubber layer having a thickness of 2.0 g / m ² to obtain a direct-drawing waterless lithographic printing plate precursor.

  Furthermore, using an etching apparatus RIE-10N manufactured by Samco Co., Ltd., in the presence of Ar gas, the flow rate was 30 (sccm), the output RF was 0 (W), the pressure was 5.33 (Pa), and the time was 5 (min). Surface treatment was performed to produce a surface state with a centerline average roughness (Ra) of 1 nm.

  Further, a 6 μm polypropylene film was laminated on the surface of the silicone rubber layer.

The obtained direct-drawing waterless planographic printing plate precursor is mounted on a plate making machine: TDL-4400 (manufactured by Panasonic CC Graphics Co., Ltd.), and a halftone dot of 1 to 99% using a semiconductor laser (wavelength 830 nm). (175 lpi) was exposed with an irradiation energy of 200 mJ / cm ² . Subsequently, with the automatic developing machine: TWL-860KII (manufactured by Toray Industries, Inc., pre-treatment part liquid: none, development part liquid: water, post-treatment part liquid: water), the above-mentioned exposure is performed at a plate conveyance speed of 80 cm / min The plate was developed to obtain a waterless lithographic printing plate. When the obtained waterless lithographic printing plate was evaluated for plate inspection, there was sufficient color contrast between the image area / non-image area, and a halftone dot of 1 to 99% could be observed. Moreover, when the dot area ratio was evaluated, it was possible to read up to 5 to 95%.

  Moreover, when printing evaluation (background stain evaluation) was performed, it was good without contamination. The results are shown in Tables 1 and 2.

(Examples 2 to 7)
A waterless CTP lithographic printing plate was prepared in the same manner as in Example 1 except that the surface of the silicone rubber layer was roughened under the dry etching conditions shown in Table 1, and the evaluation results are shown in Tables 1 and 2 Show. The plate inspection evaluation, printing evaluation (background stain evaluation), and dot area ratio evaluation were good results.

(Comparative Examples 1-3)
A waterless CTP lithographic printing plate was prepared in the same manner as in Example 1 except that the surface of the silicone rubber layer was roughened under the sputtering conditions shown in Table 1, and the results of evaluation were shown in Tables 1 and 2. . The printing evaluation (background stain evaluation) was good, but the plate inspection evaluation and the dot area ratio evaluation were insufficient.

(Comparative Examples 4 and 5)
A waterless CTP lithographic printing plate was prepared in the same manner as in Example 1 except that the surface of the silicone rubber layer was roughened under the sputtering conditions shown in Table 1, and the results of evaluation were shown in Tables 1 and 2. . The plate inspection evaluation and the dot area ratio evaluation were good, but the printing evaluation (background stain evaluation) was insufficient.

Claims (2)

  A waterless lithographic printing plate precursor having at least a photosensitive layer or a heat-sensitive layer and a silicone rubber layer on a substrate, the center average roughness (Ra) of the surface of the silicone rubber layer being from 1 nm to 100 nm. A waterless lithographic printing plate precursor.   2. The waterless planographic printing plate precursor according to claim 1, wherein the surface of the silicone rubber layer is roughened by a dry etching process.