JP4983514B2 - Waterless planographic printing plate precursor - Google Patents

Description

  The present invention relates to a waterless planographic printing plate precursor that can be printed without using dampening water.

  So far, various printing plates for performing lithographic printing without using dampening water (hereinafter referred to as waterless lithographic printing) using silicone rubber or fluororesin as an ink repellent layer have been proposed. 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. ) Broadly divided into methods. Examples of the CTP method include a method of irradiating a laser beam, a method of writing with a thermal head, a method of partially applying a voltage with a pin electrode, and a method of forming an ink repellent layer or an ink receiving layer by inkjet. The method using light is superior to other methods in terms of resolution and plate making speed.

  In addition, the waterless lithographic printing plate precursor has a photosensitive (thermal) layer removal type in which the photosensitive (thermal) layer is removed in the exposure process or the development process, and the photosensitive (thermal) layer remains even after the exposure process and the development process. It is roughly classified into a photosensitive (thermal) layer remaining 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, in the photosensitive (thermal) layer remaining type, since the photosensitive (thermal) layer in the image area remains after development, the amount of ink used during printing is small and fine image reproducibility is also good. In particular, in the case of the CTP method, 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 at the time of laser irradiation, and a special suction device is not necessary. However, since the photosensitive (thermal) layer remains in both the image area and the non-image area, it is difficult to obtain color contrast between the image area and the non-image area, and it is difficult to perform plate inspection.

  In a method for producing a lithographic printing plate using a waterless lithographic printing plate precursor of a heat-sensitive layer remaining type, a method having a step of dyeing a plate has been proposed. 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. .

  On the other hand, a waterless lithographic printing plate precursor containing a photobleachable substance or a photochromic substance in the silicone rubber layer (see, for example, Patent Document 1), and a waterless CTP lithographic plate containing a dye in the silicone rubber layer A printing plate precursor (see, for example, Patent Document 2) 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, for example, the dye is adsorbed on 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.

  On the other hand, a waterless lithographic printing plate precursor (for example, see Patent Document 3) containing a pigment in a silicone rubber layer has been proposed. However, the type of pigment that can be used, the method of dispersing the pigment, etc. are unknown, and the effect could not be confirmed. Further, a waterless lithographic printing plate precursor (for example, see Patent Document 4) containing fine particles in a silicone rubber layer has been proposed. Also here, the dispersion method of the fine particles is unknown and the effect cannot be confirmed, and the proposed fine particles are white extender pigments such as silica and mica, and the purpose is to improve the physical properties of the silicone rubber layer. The purpose itself was different from the coloring of the silicone rubber layer with the colored pigment of the invention.

  On the other hand, various proposals have been made regarding a method for coloring a silicone oil with a colored pigment (for example, see Patent Document 5) and a method for coloring a silicone rubber (for example, see Patent Document 6). Since various performances (sensitivity / image reproducibility, ink repellency, adhesion to photosensitive (thermal) layer, etc.) necessary for a lithographic printing plate are deteriorated, these techniques cannot be used.

Thus, there has been a demand for the development of a colored silicone rubber layer that can impart plate inspection properties to the plate material itself without deteriorating various performances necessary for a waterless lithographic printing plate.
JP-A-9-189993 (Claims) JP 2002-244279 A (Claims) JP 63-061052 A (first page) JP 2001-225565 A (Claims) Japanese Patent Laid-Open No. 5-140455 (Claims) Japanese Patent Laid-Open No. 5-140471 (Claims)

  In view of the above-mentioned problems of the prior art, the present invention can perform plate inspection without requiring a post-dyeing step, can be handled in a bright room, has excellent dye fixing properties in a silicone rubber layer, and has a high level. The object is to provide a sensitive waterless lithographic printing plate precursor.

  The present invention is a waterless lithographic printing plate precursor having a photosensitive layer or a heat-sensitive layer and a silicone rubber layer containing a colored pigment on a substrate, wherein the volume concentration of the colored pigment in the silicone rubber layer is 5% by volume or less. And a waterless lithographic printing plate precursor characterized in that the average particle size of the colored pigment is 400 nm or less.

  According to the present invention, it is possible to perform plate inspection without the need for a post-dyeing step, it is possible to handle in a bright room, excellent dye fixing property in a silicone rubber layer, and high sensitivity waterless lithographic printing. A plate original is obtained.

  The waterless lithographic printing plate precursor of the present invention is a waterless lithographic printing plate precursor having a photosensitive layer or a heat-sensitive layer and a silicone rubber layer containing a colored pigment on a substrate, wherein the colored pigment is contained in the silicone rubber layer. The volume concentration is 5% by volume or less, and the average particle diameter of the colored pigment is 400 nm or less. Here, in the present invention, the colored pigment refers to a pigment that absorbs any light in the visible light wavelength region (380 to 780 nm).

  In the present invention, it is important to include a colored pigment in the silicone rubber layer. In general, pigments are insoluble in organic solvents such as water and aliphatic hydrocarbons. Therefore, when pigments are included, water and organics used in the development process are compared to when pigments are soluble in water and organic solvents. Extraction of dyes by solvents, various cleaning agents, and the like in inks used in chemicals and printing processes is remarkably suppressed.

  Colored pigments are classified into colored inorganic pigments and colored organic pigments. Examples of colored inorganic pigments include oxides such as bengara (ferric oxide), chromium oxide, cobalt blue, and iron black, complex oxides thereof, yellow iron oxide, hydroxides such as viridian, vermilion, and cadmium. Sulfides and selenides such as yellow and cadmium red, ferrocyanides such as bitumen, chromates such as chrome yellow, zinc chromate, molybdenum red and strontium chromate, hydrous oxalates, oxalates such as ultramarine, garnet, Examples thereof include phosphates such as manganese violet and carbon black. Examples of the colored organic pigment include extender pigments (barite powder, precipitated barium sulfate, barium carbonate, lime carbonate powder, precipitated calcium carbonate, gypsum, asbestos, clay, silica powder, diatomaceous earth, talc, basic magnesium carbonate, alumina. Examples thereof include printing pigments dyed with dyes on white, azo pigments, phthalocyanine pigments, condensed polycyclic pigments, nitro pigments, nitroso pigments, alkali blue, aniline black, and the like. Examples of dyes used as printing pigment materials include basic dyes such as rhodamine and methyl violet, acidic dyes such as quinoline yellow, peacock blue, and alkali blue, vat dyes such as malachite green, and mordant dyes such as alizarin. . Specific examples of the azo pigments include soluble azo such as Resol Red, Lake Red C, Brilliant Carmine 6B, Watch Young Red, Bordeaux 10B, Fast Yellow, Disazo Yellow, Pyrazolone Orange, Para Red, Lake Red 4R, and Naphthol Red. Insoluble azo such as Chromophthal Yellow 3G, condensed azo such as Chromophthal Scarlet RN, azo complex salts such as Nickel Azo Yellow, and benzimidazolone azo such as Permanent Orange HL. Specific examples of the phthalocyanine pigment include phthalocyanine blue, fast sky blue, and phthalocyanine green. Specific examples of the condensed polycyclic pigment include anthraquinone pigments, anthrapyrimidine yellow, perinone orange, perylene red, thioindigo red, indantron blue and other slen pigments, quinacridone red, quinacridone violet and other quinacridone pigments, Examples thereof include dioxazine pigments such as oxazine violet and isoindolinone pigments such as isoindolinone yellow. Examples of the nitro pigment include naphthol yellow S, and examples of the nitroso pigment include naphthol green B.

  In the present invention, it is important that the water-less planographic printing plate after exposure and development has good plate inspection. As the plate inspection property of the waterless lithographic printing plate, in addition to the visual plate inspection property by visual observation, it is necessary that the device plate inspection property by the halftone dot area ratio measuring device is good. In general, since device inspection is more severe than visual inspection, waterless lithographic printing plates with good device inspection often have good visual inspection as well.

  A general halftone dot area ratio measuring device has blue light (wavelength 400 to 500 nm), green light (wavelength 500 to 600 nm), red light (wavelength 600 to 700 nm), on a halftone dot portion formed on a printing plate. Alternatively, white light (wavelength of 400 to 700 nm) is irradiated, and the halftone dot area ratio is calculated from the difference in the amount of reflected light between the image area / non-image area. When the difference in the amount of reflected light between the image area and the non-image area is large, a good dot area ratio measurement is possible, but the case where the difference in the amount of reflected light between the image area and the non-image area is small or not. In such a case, good dot area ratio measurement cannot be performed. Silicone rubber layers colored with colored pigments such as yellow and orange that absorb blue light because many of the organic compounds that compose the primer layer and photosensitive (thermal) layer of waterless planographic printing plate precursors absorb blue light. Is used, the difference in the amount of reflected light between the image area / non-image area becomes small, and the measurement of the dot area ratio may be poor. Further, when a silicone rubber layer colored with a colored pigment such as yellow or orange that absorbs blue light is used, visual inspection may be difficult. For these reasons, it is preferable to use a colored pigment that absorbs green light or red light from the viewpoint of instrument plate inspection and visual plate inspection. Among the above-mentioned colored pigments, the colored pigments that absorb green light or red light include bengara (ferric oxide), chromium oxide, cobalt blue, iron black, viridian, vermilion, cadmium red, bitumen, and molybdenum red. , Hydrous oxalate, ultramarine, garnet, manganese violet, carbon black, extender pigments dyed with rhodamine, methyl violet, peacock blue, alkali blue, malachite green, alizarin and other dyes, alkali blue, aniline black, Risor Red, Lake Red C, Brilliant Carmine 6B, Watch Young Red, Bordeaux 10B, Para Red, Lake Red 4R, Naphthol Red, Chromophthal Scarlet RN, Phthalocyanine Blue, Fast Sky Blue, Phthalocyanine Down, anthraquinone pigments, perylene red, thioindigo red, indanthrone blue, quinacridone red, quinacridone violet, dioxazine violet, include naphthol green B.

Further, among these colored pigments that absorb green light or red light, it is preferable to use a colored pigment having a density of 3 g / cm ³ or less from the viewpoint of suppression of colored pigment precipitation in the silicone liquid and the diluted silicone liquid. Among the above-mentioned colored pigments that absorb green light or red light, the colored pigments having a density of 3 g / cm ³ or less include cobalt blue, bitumen, hydrous oxalate, ultramarine, carbon black, extender pigment (lime carbonate Powder, precipitated calcium carbonate, gypsum, asbestos, clay, silica powder, diatomaceous earth, talc, basic magnesium carbonate, alumina white) dyed with dyes such as rhodamine, methyl violet, peacock blue, alkali blue, malachite green, alizarin Textile pigments, alkali blue, aniline black, resol red, lake red C, brilliant carmine 6B, watch young red, Bordeaux 10B, para red, lake red 4R, naphthol red, chromophthalscarlet RN, phthalocyanine blue, fast sky Blue, phthalocyanine green, anthraquinone pigment, perylene red, thioindigo red, indanthrone blue, quinacridone red, quinacridone violet, dioxazine violet, and naphthol green B.

  In the waterless planographic printing plate precursor of the present invention, the content (volume concentration) of the colored pigment is 5% by volume or less from the viewpoint of suppressing the ink resilience of the silicone rubber layer and the decrease in sensitivity and image reproducibility of the plate material. It is preferable that it is 4 volume% or less. Further, from the viewpoint of plate inspection, the content of the colored pigment is preferably 0.1% by volume or more in the silicone rubber layer, and more preferably 0.2% by volume or more.

  The average particle diameter of the colored pigment contained in the silicone rubber layer constituting the waterless lithographic printing plate precursor of the present invention reduces the sensitivity and image reproducibility of the plate material in terms of imparting plate inspection properties (coloring power). From the viewpoint of suppression, it is necessary to be 400 nm or less, and preferably 150 nm or less. A semiconductor laser with a wavelength of 830 nm is used for exposure of the thermal type waterless CTP lithographic printing plate precursor. By setting the average particle size of the colored pigment in the silicone rubber layer to 400 nm or less, the sensitivity / image of the plate material A decrease in reproducibility can be suppressed. Furthermore, for the exposure of waterless lithographic printing plate precursors with ultraviolet irradiation through the original film, among the light of each wavelength irradiated from a light source such as a high pressure mercury lamp, an ultra high pressure mercury lamp, a xenon lamp, a metal halide lamp, The i-line with a wavelength of 365 nm and the h-line with a wavelength of 405 nm are used, and a violet laser with a wavelength of 405 nm and an Ar laser with a wavelength of 488 nm are used for exposing a visible waterless CTP lithographic printing plate precursor. By making the average particle diameter of the colored pigment in the layer 150 nm or less, it is possible to suppress a decrease in sensitivity and image reproducibility of the plate material. Although no elucidation has been made regarding this mechanism, and there is no hypothesis, the colored pigment contained in the silicone rubber layer most scatters light having a wavelength twice as long as its average particle diameter. Since light transmission in the layer is hindered, it is considered that sensitivity and image reproducibility may be reduced.

  The average particle size of the colored pigment dispersed in the silicone rubber layer can be calculated by observing the cross section of the silicone rubber layer with a transmission electron microscope. Details of measurement and analysis are described in the examples.

  In the waterless planographic printing plate precursor of the present invention, the silicone rubber layer 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.

In the formula, a 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. R ¹ and R ² are preferably 50% or more of 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. The weight average molecular weight of the vinyl group-containing organopolysiloxane in the present invention represents a polystyrene equivalent value measured by a GPC (gel permeation chromatography) method using polystyrene as a standard substance.

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.

The organic polymer having a diorgano hydrogen silyl group, for example, dimethyl hydrogen silyl (meth) acrylate Li rate, and dimethyl hydrogen silyl group-containing acrylic monomer such as dimethyl hydrogen silyl propyl (meth) acrylate, (meth ) Methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ethyl hexyl (meth) acrylate, lauryl (meth) acrylate, styrene, α-methylstyrene, maleic acid, vinyl acetate, allyl acetate, etc. Examples include oligomers copolymerized with monomers.

  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 (II) 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 the formula, b represents an integer of 2 or more, and R ³ and R ⁴ 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. From the viewpoint of ink repellency of the printing plate, it is preferable that 50% or more of R ³ and R ⁴ in the general formula (II) are 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. The weight average molecular weight of the hydroxyl group-containing organopolysiloxane in the present invention represents a polystyrene equivalent value measured by a GPC (gel permeation chromatography) method using polystyrene as a standard substance.

  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 (III).

In the formula, d represents an integer of 2 to 4, R ⁵ may be the same or different, and represents a substituted or unsubstituted alkyl group, alkenyl group, aryl group having 1 or more carbon atoms, or a combination thereof. Show. A 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 d 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.

  In order to improve the dispersibility of the colored pigment in the colored pigment-containing silicone liquid or the colored pigment-containing silicone dilution liquid and in the silicone rubber layer, it is preferable to contain a pigment dispersant in the silicone rubber layer. By containing the pigment dispersant, it is possible to suppress aggregation of the colored pigment that occurs when diluted with a solvent or with the passage of time of the colored pigment-containing silicone (diluted) liquid, and a good coating film can be obtained. Further, when there are huge particles such as poorly dispersed colored pigments in the diluted low viscosity colored pigment containing silicone diluted solution, they can be removed with a filter or the like.

  The pigment dispersant used in the present invention is preferably a pigment dispersant that wets the pigment surface well and has good affinity with organopolysiloxane and a low-polarity compound such as a solvent used for diluting the colored pigment-containing silicone liquid. If it is such a pigment dispersant, a well-known pigment dispersant can be used. The pigment dispersant may be used in the name of a surfactant or a surface modifier. Examples of the pigment dispersant include an organic complex compound composed of a metal and an organic compound, an amine pigment dispersant, an acid pigment dispersant, and a nonionic surfactant. Among these, an organic complex compound composed of a metal and an organic compound or an amine pigment dispersant is preferable.

  Below, what is preferably used as an organic complex compound which consists of a metal and an organic compound is illustrated. As the metal, Cu (I), Ag (I), Hg (I), Hg (II), Li, Na, K, Be (II), B (III), Zn (II), Cd (II), Al (III), Co (II), Ni (II), Cu (II), Ag (II), Au (III), Pd (II), Pt (II), Ca (II), Sr (II), Ba (II), Ti (IV), V (III), V (IV), Cr (III), Mn (II), Mn (III), Fe (II), Fe (III), Co (III), Pd (IV), Pt (IV), Sc (III), Y (III), Si (IV), Sn (II), Sn (IV), Pb (IV), Ru (III), Rh (III), Os (III), Ir (III), Rb, Cs, Mg, Ni (IV), Ra, Zr (IV), Hf (IV), Mo (IV), W (IV), Ge, In, lanthanide, actinide Etc. Among these, Al, Ti, Mn, Fe, Co, Ni, Cu, Zn, Ge, In, Sn, Zr, and Hf are preferable, and Al and Ti are more preferable.

Examples of the organic compound include compounds having a coordination group having O (oxygen atom), N (nitrogen atom), S (sulfur atom), or the like as a donor atom. Specific examples of the coordinating group include those having an oxygen atom as a donor atom, -OH (alcohol, enol and phenol), -COOH (carboxylic acid),> C = O (aldehyde, ketone, quinone),- O- (ether), - COOR '(ester, R': represents an aliphatic or aromatic hydrocarbon), - N = O (nitroso compounds), - NO ₂ (nitro compound),> NO (N- Oxides), —SO ₃ H (sulfonic acid), —PO ₃ H ₂ (phosphorous acid), etc., with a nitrogen atom as a donor atom, —NH ₂ (primary amine, amide, hydrazine),> NH (secondary amine, hydrazine),> N-(3 amine), - N = N- (azo compounds, heterocyclic compounds), = N-OH (oxime), - NO ₂ (nitro compound), - N = O (nitroso compound),> = N- (Schiff base, heterocyclic compound),> C = NH (aldehyde, ketone imine, enamines), -NCS (isothiocyanato), etc., with a sulfur atom as a donor atom, -SH (thiol), -S- (thioether),> C = S (thioketone, thioamide), = S- (heterocyclic compound), -C (= O) -SH or -C (= S) -OH and -C (= S) -SH (thiocarboxylic acid), -SCN (thiocyanato), etc. are mentioned. Among them, it is preferable from the viewpoint of the coordination power with the metal to use an acid compound such as carboxylic acid, phosphoric acid or sulfonic acid, or a diketone, ketoester or diester compound capable of forming a chelate ring with the metal. Although the specific example of an organic compound is given to the following, it is not limited to these.

In the above formula, R ⁶ represents a saturated or unsaturated hydrocarbon group, which may be linear, branched or cyclic, and may contain an aromatic ring. From the viewpoint of dispersibility, R ⁶ preferably has 8 or more carbon atoms. R ⁷ represents a saturated or unsaturated divalent hydrocarbon group having 3 or more carbon atoms, and may be linear, branched or cyclic. e represents the number of repetitions and is an integer of 1 or more. From the viewpoint of dispersibility, the total number of carbon atoms contained in e R ⁷ is preferably 8 or more. R ⁸ and R ⁹ represent a saturated or unsaturated hydrocarbon group, which may be linear, branched or cyclic, and may contain an aromatic ring. From the viewpoint of dispersibility, the total number of carbon atoms of R ⁸ and R ⁹ is preferably 8 or more. R ¹⁰ represents a saturated or unsaturated hydrocarbon group having 1 or more carbon atoms, and may be linear, branched or cyclic, and may contain an aromatic ring. R ¹¹ represents a saturated or unsaturated divalent hydrocarbon group having 3 or more carbon atoms, and may be linear, branched or cyclic. f represents the number of repetitions and is an integer of 1 or more. From the viewpoint of dispersibility, the total number of carbon atoms contained in R ¹⁰ and the number of carbon atoms contained in f R ¹¹ is preferably 8 or more. R ¹² and R ¹³ represent a saturated or unsaturated divalent hydrocarbon group having 3 or more carbon atoms, and may be linear, branched or cyclic. The plurality of R ¹² and R ¹³ may be the same or different. g and h represent the number of repetitions, and each is an integer of 1 or more. From the viewpoint of dispersibility, the total number of carbon atoms contained in g R ¹² and h carbon atoms contained in R ¹³ is preferably 8 or more. G represents hydrogen, an alkyl group or an aryl group. D and E represent a divalent group represented by any of the following, and may be the same or different.

  In the above formula, J represents hydrogen, an alkyl group or an aryl group.

  The simplest organic complex compound used as a pigment dispersant can be obtained by stirring the organic compound and metal alkoxide at room temperature or under heating and exchanging the ligand. It is preferable to coordinate one or more molecules of the organic compound to one metal.

  An example of a commercially available organic complex compound composed of a metal and an organic compound is given below. Aluminum series: “Octope” (registered trademark) Al, “Olyp” (registered trademark) AOO, AOS (above, manufactured by Hope Pharmaceutical Co., Ltd.), “Plenact” (registered trademark) AL-M (Ajinomoto Fine Techno Co., Ltd.) Made) etc. Titanium: “Plenact” (registered trademark) KR-TTS, KR46B, KR55, KR41B, KR38S, KR138S, KR238S, KR338X, KR9SA (above, Ajinomoto Fine Techno Co., Ltd.), “KEN-REACT” (registered trademark) TTS-B 5, 6, 7, 10, 11, 12, 15, 26S, 37BS, 43, 58CS, 62S, 36B, 46B, 101, 106, 110S, 112S, 126S, 137BS, 158DS, 201, 206, 212, 226, 237, 262S (above, manufactured by KENRICH).

  The organic complex compound can be suitably used particularly for an addition reaction type silicone rubber layer. In particular, organic complex compounds that do not contain primary or secondary amines, phosphorus, or sulfur in the molecule do not act as catalyst poisons for platinum catalysts. Therefore, when used for addition reaction type silicones that promote curing using platinum catalysts. It is very suitable for.

  On the other hand, as the amine pigment dispersant, there are a monoamine type having one amino group in the molecule and a polyamine type having a plurality of amino groups in the molecule, both of which can be suitably used. Specifically, “Solsperse” (registered trademark) 9000, 13240, 13650, 13940, 17000, 18000, 19000, 28000 (manufactured by Avicia) and amine compounds described in the following general formula can be exemplified. .

In the above formula, R ¹⁴ represents a saturated or unsaturated hydrocarbon group, which may be linear, branched or cyclic, and may contain an aromatic ring. From the viewpoint of dispersibility, R ¹⁴ preferably has 8 or more carbon atoms. R ¹⁵ represents a saturated or unsaturated divalent hydrocarbon group having 3 or more carbon atoms, and may be linear, branched or cyclic. i represents the number of repetitions and is an integer of 1 or more. From the viewpoint of dispersibility, the total number of carbon atoms contained in i R ¹⁵ is preferably 8 or more. R ¹⁶ and R ¹⁷ represent a saturated or unsaturated hydrocarbon group, which may be linear, branched or cyclic, and may contain an aromatic ring. From the viewpoint of dispersibility, the total number of carbon atoms of R ¹⁶ and R ¹⁷ is preferably 8 or more. R ¹⁸ represents a saturated or unsaturated hydrocarbon group having 1 or more carbon atoms, and may be linear, branched or cyclic, and may contain an aromatic ring. R ¹⁹ represents a saturated or unsaturated divalent hydrocarbon group having 3 or more carbon atoms, and may be linear, branched or cyclic. j represents the number of repetitions and is an integer of 1 or more. From the viewpoint of dispersibility, the total number of carbon atoms contained in R ¹⁸ and the number of carbon atoms contained in j R ¹⁹ is preferably 8 or more. R ²⁰ and R ²¹ represent a saturated or unsaturated divalent hydrocarbon group having 3 or more carbon atoms, and may be linear, branched or cyclic. The plurality of R ²⁰ and R ²¹ may be the same or different. k and m represent the number of repetitions, and each is an integer of 1 or more. From the viewpoint of dispersibility, the total number of carbon atoms contained in k R ²⁰ and m carbon atoms contained in R ²¹ is preferably 8 or more. L and M represent a divalent group represented by any of the following, and may be the same or different.

The pigment dispersant is preferably contained in an amount of ² to 30 mg / m ^{2 with} respect to the surface area of the pigment. In other words, for example, when 10 g of a pigment having a specific surface area of 50 m ² / g is contained, the content of the pigment dispersant is preferably 1 to 15 g.

As a solvent used for the dispersion of the colored pigment, the silicone liquid, and the dilution of the colored pigment-containing silicone liquid, a low-polarity solvent is preferable. Among them, a solvent having a solubility parameter of 17.0 (MPa) ^1/2 or less is used. solubility, lay preferable from the viewpoint of coatability, and more preferably 15.5 ^{(MPa) 1/2} or less. A solvent may be used individually by 1 type, or may use 2 or more types. When two or more solvents are used, the solubility parameter of any solvent is preferably 17.0 (MPa) ^1/2 or less.

The solubility parameter refers to an amount δ defined by δ = (ΔH / V) ^1/2 where ΔH is the heat of molar evaporation of the liquid and V is the molar volume. The unit for the solubility parameter is (MPa) ^1/2 . As a unit of the solubility parameter, (cal · cm ⁻³ ) ^1/2 is also commonly used, and δ (MPa) ^1/2 = 2.0455 × δ (cal · cm ⁻³ ) is used between both units. ) There is a ^1/2 relational expression. Specifically, the solubility parameter 17.0 (MPa) ^1/2 is 8.3 (cal · cm ⁻³ ) ^1/2 . Solvent parameters of 17.0 (MPa) ^1/2 or less include aliphatic saturated hydrocarbons, aliphatic unsaturated hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, and ethers. For example, hexane, heptane, octane, nonane, decane, undecane, dodecane, isooctane, “Isopar” (registered trademark) C, “Isopar” (registered trademark) E, “Isopar” (registered trademark) G, “Isopar” (registered) Trademarks) H, “Isoper” (registered trademark) K, “Isoper” (registered trademark) L, “Isoper” (registered trademark) M (manufactured by Exxon Chemical Co., Ltd.), etc., aliphatic saturated hydrocarbons, hexene, heptene, Aliphatic unsaturated hydrocarbons such as octene, nonene and decene, alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclohexane, halogenated hydrocarbons such as trifluorotrichloroethane, ethers such as diethyl ether, diisopropyl ether and diisobutyl ether However, it is not limited to these. Aliphatic and alicyclic hydrocarbons are preferred from the viewpoint of economy and safety. These aliphatic and alicyclic hydrocarbons preferably have 4 to 20 carbon atoms, and more preferably 6 to 15 carbon atoms.

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 . When the film thickness is 0.5 g / m ² or more, the ink repellency, scratch resistance and printing durability of the printing plate are sufficient, and when the film thickness is 20 g / m ² or less, there is no disadvantage from an economic standpoint. 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 positive-type waterless lithographic printing plate precursor Examples of the photosensitive layer include those 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 the coated surface with a solvent is applied to the substrate on which the coating surface has been 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. Moreover, when providing a metal thin film as a heat-sensitive layer, general methods, such as a vapor deposition method and sputtering method, are used. A common heating device such as a hot air dryer or an infrared dryer is used for heating each layer.

  The colored pigment-containing silicone rubber layer is obtained by applying (i) a colored pigment-containing silicone liquid (no solvent) or (ii) a colored pigment-containing silicone diluent (containing a solvent) on the photosensitive (thermal) layer. If necessary, heat treatment for drying or curing may be performed. Hereinafter, a specific method for producing each liquid will be described.

(I) Colored pigment-containing silicone liquid (no solvent)
Colored pigment-containing silicone liquid is, for example, hydroxyl group or vinyl group-containing organopolysiloxane and colored pigment, if necessary, pigment dispersant, three rolls of fine particles, ball mill, bead mill, sand mill, disperser, homogenizer, attritor, ultrasonic dispersion Add the cross-linking agent and other additives (reaction inhibitor, reaction catalyst, etc.) as needed to the colored pigment-dispersed silicone paste obtained by uniformly dispersing and mixing with a disperser such as The components are made uniform and air bubbles mixed in the liquid are removed. The defoaming may be natural defoaming or vacuum defoaming, but vacuum defoaming is more preferable.

(Ii) Colored pigment-containing silicone diluent (containing solvent)
The colored pigment-containing silicone diluent preferably contains a pigment dispersant from the viewpoint of dispersibility of the colored pigment. A method for producing a colored pigment-containing silicone diluent will be described with reference to an example. First, a colored pigment-dispersed silicone paste obtained by uniformly dispersing and mixing a hydroxyl group or vinyl group-containing organopolysiloxane, a colored pigment, a pigment dispersant, and, if necessary, fine particles with the aforementioned disperser is diluted with a solvent while stirring. It is preferable to filter this using a general filter such as paper, plastic, or glass to remove impurities (such as giant particles of colored pigment that are not sufficiently dispersed) in the diluent. It is preferable to remove the water in the system by bubbling with dry air, dry nitrogen or the like from the diluted solution after filtration. Add the cross-linking agent and other additives (reaction inhibitor, reaction catalyst, etc.) to the diluted solution from which water has been sufficiently removed, and stir to homogenize the components. Remove foam. Defoaming may be natural defoaming or vacuum defoaming .

  In addition, as another method for preparing the colored pigment-containing silicone diluent, a method in which a colored pigment dispersion and a silicone solution or a silicone diluent are separately prepared in advance, and the two solutions are mixed later. The colored pigment dispersion is obtained by adding a colored pigment and, if necessary, fine particles to a solution containing at least a pigment dispersant and a solvent, and uniformly dispersing and mixing them with the above-described disperser. On the other hand, the silicone liquid can be obtained by mixing a hydroxyl group or vinyl group-containing organopolysiloxane, a crosslinking agent, and other additives (reaction inhibitor, reaction catalyst, etc.) as required. Moreover, a silicone dilution liquid can be obtained by diluting the obtained silicone liquid with a solvent. As an advantage of this production method, the colored pigment dispersion liquid has a very low viscosity as compared with the colored pigment-dispersed silicone paste, and therefore, it is easy to redisperse the colored pigment aggregated over time. In addition, since the colored pigment is dispersed in the dilution solvent in advance, the aggregation of the colored pigment that occurs when the solvent is diluted is less likely to occur than in the method of diluting the colored pigment-dispersed silicone paste with the solvent. Furthermore, in the dispersion process using a disperser, the colored pigment dispersion does not contain a silicone material, so that the disperser is not contaminated by the silicone material.

  When applying the colored pigment-containing silicone liquid or the colored pigment-containing silicone diluent, it is preferable from the viewpoint of adhesiveness to remove as much water as possible attached to the surface of the photosensitive (heat) layer. Specifically, a method of applying the colored pigment-containing silicone liquid or the colored pigment-containing silicone dilution liquid in a space where moisture is removed by filling or continuously supplying a dry gas can be mentioned.

  The colored pigment-containing silicone liquid or the colored pigment-containing silicone diluent is preferably heated immediately after coating from the viewpoints of curability and adhesion to the photosensitive (heat) layer.

  On the obtained waterless lithographic printing plate precursor, it is preferable from the viewpoint of plate surface protection to provide a protective film and / or a slip sheet and store them.

  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.

  Examples of 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 JP-A-3716429. 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 processor include TWL-650 series, TWL-860 series, TWL-1160 series (manufactured by Toray Industries, Inc.), TWL-860CF, TWL-1160CF (manufactured by Toyo Shoji Co., Ltd.), Examples thereof include automatic developing machines disclosed in JP-A-4-2265, JP-A-5-2272, JP-A-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.

  Hereinafter, the present invention will be described in more detail with reference to examples. Each silicone rubber layer component is weighed in a glove box that has drained the moisture in the box, and each component is dispersed and mixed in a container filled with dry nitrogen gas to form a silicone liquid or a silicone diluent. Was prepared.

  The colored pigment dispersion used for the preparation of the colored pigment-containing silicone diluent was prepared by the following method.

<Method for preparing colored pigment dispersion>
Zirconia beads: In a sealable glass standard bottle filled with 2000 g of “YTZ” (registered trademark) balls (φ0.6 mm, manufactured by Nikkato Co., Ltd.), “Isopar” (registered trademark) G (Esso Chemical Co., Ltd.) Manufactured): 420 g, “Plenact” (registered trademark) KR-TTS: 40 g, N650 bitumen (manufactured by Dainichi Seika Co., Ltd.): 100 g, and after sealing, a small ball mill rotary mount (manufactured by ASONE Co., Ltd.) A colored pigment dispersion was obtained by setting and dispersing for a predetermined time at a rotation speed of 500 rpm. The longest dispersion time was set to 480 hours, and sampling was performed every 6 hours.

  The average particle diameter measurement and image reproducibility of the colored pigment in each example were evaluated by the following methods.

<Measurement of average particle size of colored pigment>
The cross section of the silicone rubber layer of the waterless planographic printing plate precursor was observed at a magnification of 10,000 using a transmission electron microscope H-7100FA (manufactured by Hitachi, Ltd.). The section thickness of the sample used for observation was 1 μm, and 10 fields of view were measured at different locations. The average particle diameter d of the colored pigment is obtained from the equivalent circle equivalent diameter and is defined by the following equation.

  In the formula, N represents the number of colored pigments. In this example, 10 colored pigments were randomly selected from 10 per visual field and 10 visual fields, and the average particle diameter d was calculated.

<Image reproducibility evaluation>
1 to 99% of halftone dots (175 lpi) on the waterless lithographic printing plate obtained by exposure and development were observed with a loupe (× 50) and evaluated according to the following criteria.
◎: Reproduction of halftone dot of 1 to 99% ○: (Negative waterless CTP lithographic plate) Reproduction of 2 to 99% of halftone dot (Positive waterless lithographic plate) Reproduction of 1 to 98% halftone dot △: ( (Negative waterless CTP lithographic plate) 3 to 99% of halftone dots are reproduced, (Positive type waterless lithographic plate) 1 to 97% of halftone dots are reproduced ×: (Negative waterless CTP lithographic plate) 5 to 99% of halftone dots Reproduction, (Positive waterless lithographic plate) Reproduces 1-95% halftone dots.

<Verification>
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, cyan was selected as the measurement color, and the dot area ratio of 50% halftone dots on a waterless lithographic printing plate obtained by exposure and development was measured three times, and then 5% and 20% , 35%, 50%, 65%, 80%, and 95%, each halftone dot area ratio was measured three times, and the average value was defined as the halftone dot area ratio (below the decimal point of the average value) Rounded to the first place). In the waterless planographic printing plate precursor of the present invention, the uppermost silicone rubber layer is colored, so the waterless planographic printing plate after exposure and development becomes a negative image (non-image area: dark color, Image area: light color). From this, the dot area ratio measurement was performed in the negative (display on the apparatus:-(minus)) mode.
: Accurate reading (Maximum measurement error: ± 1% or less)
○: Can be read almost accurately (maximum measurement error: ± 2% to 3%)
×: There is a lot of noise and cannot be read accurately (maximum measurement error: ± 4% or more)

(Examples 1-5, Comparative Examples 1-2)
The following primer layer composition liquid-1 is applied onto a 0.24 mm thick degreased aluminum substrate (Mitsubishi Aluminum Co., Ltd.), dried at 200 ° C. for 90 seconds, and a primer layer having a thickness of 10 g / m ² . Was provided.

<Primer layer composition liquid-1>
(A) Epoxy resin: “Epicoat” (registered trademark) 1010 (manufactured by Japan Epoxy Resin Co., Ltd.): 35 parts by weight (b) Polyurethane: “Samprene” (registered trademark) LQ-T1331D (manufactured by Sanyo Chemical Industries, Ltd.) (Solid content concentration: 20% by weight): 375 parts by weight (c) Aluminum chelate: “Aluminum chelate” ALCH-TR (manufactured by Kawaken Fine Chemical Co., Ltd.): 10 parts by weight (d) Leveling agent: “Disparon” (registered) (Trademark) LC951 (manufactured by Enomoto Kasei Co., Ltd., solid content: 10% by weight): 1 part by weight (e) Titanium oxide: N, N of “Taipeke” (registered trademark) CR-50 (manufactured by Ishihara Sangyo Co., Ltd.) -Dimethylformamide dispersion (titanium oxide 50% by weight): 60 parts by weight (f) N, N-dimethylformamide: 730 parts by weight (g) Methyl ethyl ketone: 250 parts by weight.

Subsequently, the following heat sensitive layer composition liquid-1 was apply | coated on the said primer layer, and it heated at 120 degreeC for 90 second, and provided the heat sensitive layer with a film thickness of 1.5 g / m < ² >.

<Thermosensitive layer composition liquid-1>
(A) Infrared absorbing dye: “PROJET” 825LDI (manufactured by Avecia): 10 parts by weight (b) Titanium chelate: “Narsem” titanium (manufactured by Nippon Chemical Industry Co., Ltd., solid content concentration: 73% by weight): 11 parts by weight (c) phenol formaldehyde novolac resin: “Sumilite Resin” PR50731 (manufactured by Sumitomo Durez): 75 parts by weight (d) polyurethane: “Samprene” (registered trademark) IB465 (manufactured by Sanyo Chemical Industries) ) Solvent substitution product (substitution solvent: tetrahydrofuran, solid content: 15% by weight): 47 parts by weight
(E) Methyl ethyl ketone: 422 parts by weight (f) Ethanol: 85 parts by weight (g) Isoparaffin: “Isopar” (registered trademark) H (manufactured by Esso Chemical Co., Ltd.): 17 parts by weight.

Next, the following colored pigment-containing silicone diluent-1 prepared immediately before coating was applied onto the heat-sensitive layer and heated at 130 ° C. for 90 seconds to provide a silicone rubber layer having a thickness of 2.0 g / m ² . The silicone rubber layer immediately after heating was completely cured. A 6 μm-thick polypropylene film: “Trephan” (manufactured by Toray Industries, Inc.) was laminated on the silicone rubber layer immediately after heating to obtain a negative waterless CTP lithographic printing plate precursor.

<Colored Pigment-Containing Silicone Diluent-1>
The following (a) and (b) were mixed in this order to obtain a colored pigment dispersion dilution liquid-1.
(A) “Isopar” (registered trademark) E (manufactured by Esso Chemical Co., Ltd.): 342.44 parts by weight (b) Colored pigment dispersion prepared by the above method: 10.08 parts by weight.

Then, to obtain a sheet recone dilutions -1 by mixing the following (c) ~ (h) in a separate container.
(C) "Isopar" (registered trademark) E (Esso Chemical Co., Ltd.): 550 parts by weight (d) "DMS" V52 (Gerest): 81.28 parts by weight (e) "HMS" 991 (Gerest 3 parts by weight (f) Vinyl tris (methylethylketooxyimino) silane: 3 parts by weight (g) “Syra Ace” (registered trademark) S510 (manufactured by Chisso Corporation): 4 parts by weight (h) “SRX” 212 (Toray Dow Corning Silicone Co., Ltd.): 7 parts by weight.

Colored pigment-containing silicone diluent-1 was obtained by mixing silicone diluent- 1 prepared in a separate container while stirring colored pigment dispersion diluent-1 prepared in advance. The dispersion time of the colored pigment dispersion used in each experiment is as shown in Table 1.

The negative-type waterless CTP lithographic printing plate precursor after peeling the polypropylene film is mounted on a plate making machine: GX-3600 (manufactured by Toray Industries, Inc.) and a 1 to 99% halftone dot (175 lpi) using a semiconductor laser (wavelength 830 nm). ) At an irradiation energy of 200 mJ / cm ² . Subsequently, the exposed plate was developed with an automatic processor: TWL-860CF (manufactured by Toyo Shosha Co., Ltd., cleaning solution: tap water, water temperature: 35 ° C.) at a plate conveyance speed of 80 cm / min, and a waterless lithographic plate A printed version was obtained. When the image reproducibility and plate inspection property of the obtained waterless lithographic printing plate were evaluated by the above-mentioned methods, both the image reproducibility and plate inspection property were good when the average color pigment particle size in the silicone rubber layer was 400 nm or less. Met. On the other hand, when the average particle diameter of the colored pigment was larger than 400 nm, both the image reproducibility and the plate inspection were deteriorated. The evaluation results are summarized in Table 1.

(Examples 6 to 9)
The following primer layer composition liquid-2 was applied on a 0.24 mm thick degreased aluminum support (manufactured by Mitsubishi Aluminum Co., Ltd.), dried at 200 ° C. for 1 minute, and a primer with a film thickness of 3 g / m ² . A layer was provided.

<Primer layer composition liquid-2>
(A) Epoxy resin “Epicoat” 1010 (manufactured by Japan Epoxy Resin Co., Ltd.): 78.5 parts by weight (b) Titanium oxide: N of “Typaque” (registered trademark) CR-50 (manufactured by Ishihara Sangyo Co., Ltd.) , N-dimethylformamide dispersion (titanium oxide 50% by weight): 20 parts by weight (c) Reaction product of 1 mol of diphenylmethane-4,4′-diisocyanate and 2 mol of methyl ethyl ketoxime: 4.5 parts by weight (d) Surface activity Agent "Florard" FC470 (manufactured by Sumitomo 3M): 0.01 parts by weight (e) Leveling agent "Disparon" LC951 (manufactured by Enomoto Kasei Co., Ltd.): 0.05 parts by weight (f) Dibutyltin diacetate: 0.1 parts by weight (g) Resole resin “Sumilite Resin” PR-54573 (manufactured by Sumitomo Durres): 3 parts by weight (h) Tetrahydrofuran: 40 0 parts by weight (i) N, N-dimethylformamide: 165 parts by weight.

Next, the following photosensitive layer composition liquid-2 was applied on the primer layer and heated at 120 ° C. for 1 minute to provide a photosensitive layer having a thickness of 4 g / m ² .

<Photosensitive layer composition liquid-2>
(A) "Samprene" LQ-T1331D (manufactured by Sanyo Chemical Industries): 335 parts by weight (b) Reaction product of 1 mol of m-xylylenediamine and 4 mol of glycidyl methacrylate: 10 parts by weight (c) Polyoxypropylene Reaction product of 1 mol of diamine and 4 mol of glycidyl methacrylate: 10 parts by weight (d) “Light Ester” 1 · 10DC (manufactured by Kyoeisha Chemical Co., Ltd.): 8 parts by weight (e) Polyoxypropylenediamine / glycidyl methacrylate / 3- Glycidoxypropyltrimethoxysilane = 1/3/1 mole of reactant: 2 parts by weight (f) Tri (butoxycarbonylmethyl) trithiophosphite: 2 parts by weight (g) “Plastanox” 1729 (American Cyanamid Co.) 1 part by weight (h) 4,4 ′-(diethylamino) benzophenone: Parts by weight (i) 10-n-butyl-2-chloroacridone: 4 parts by weight (j) 2,4-diethylthioxanthone: 7 parts by weight (k) “Eisen Victoria Pure Blue” -BOH Conch (Hodogaya Chemical Co., Ltd.) Co., Ltd.): 0.3 parts by weight (l) “FLORARD” FC470 (manufactured by Sumitomo 3M): 0.03 parts by weight (m) 2-ethylanthraquinone: 0.02 parts by weight (n) ethyl cellosolve : 150 parts by weight (o) Methyl ethyl ketone: 400 parts by weight (p) Tetrahydrofuran: 200 parts by weight.

Next, the following colored pigment silicone diluent- 2 prepared immediately before coating was applied onto the photosensitive layer and heated at 120 ° C. for 1 minute to provide a silicone rubber layer having a thickness of 2.0 g / m ² . A polyethylene terephthalate film: “Lumirror” (manufactured by Toray Industries, Inc.) having a thickness of 6 μm was laminated on the silicone rubber layer immediately after heating to obtain a positive-type waterless lithographic printing plate precursor.

<Colored pigment-containing silicone diluent-2>
The following (a) and (b) were mixed in this order to obtain a colored pigment dispersion dilution.
(A) "Isopar" (registered trademark) E: 342.44 parts by weight (b) Colored pigment dispersion prepared by the above method: 10.08 parts by weight.

Subsequently, the following (c)-(f) was mixed in another container, and the silicone dilution liquid was obtained.
(C) "Isopar" (registered trademark) E: 550 parts by weight (d) "DMS" -S42 (manufactured by GELEST): 87.48 parts by weight (e) Ethyltriacetoxysilane: 10 parts by weight (f) Dibutyltin Diacetate: 0.01 parts by weight.

  While the colored pigment dispersion diluted solution prepared in advance was stirred, the silicone diluted solution prepared in a separate container was mixed to obtain a colored pigment-containing silicone diluted solution-2. The dispersion time of the colored pigment dispersion used in each experiment is as shown in Table 2.

  The obtained positive-type waterless lithographic printing plate precursor was exposed under the following conditions, the cover film was peeled off, and developed under the following conditions to obtain a waterless lithographic printing plate. When the image reproducibility and the plate inspection property of the obtained waterless lithographic printing plate were evaluated by the above-described methods, both the image reproducibility and the plate inspection property were good when the average particle diameter of the colored pigment in the silicone rubber layer was 147 nm or less. Met. On the other hand, when the average particle diameter of the colored pigment was 182 nm, the image reproducibility was lowered. The evaluation results are summarized in Table 2.

(Exposure conditions)
Exposure machine: "Idle fin" ID-2000 (Oak Manufacturing)
Light meter: “Light measure” UV365 (Oak Manufacturing)
Exposure conditions: Positive film vacuum contact (30 seconds)
11 mW / cm ² (365 nm light) × 60 seconds exposure exposure plate temperature: 25 ° C.
Film: Positive film-halftone dot 1% -99% (175 lpi)

(Development conditions)
Developer: “TWL” -860KII (manufactured by Toray Industries, Inc.)
Developer: Pretreatment solution 35 ° C. “PP-F” (manufactured by Toray Industries, Inc.)
Developer Tap water post-treatment solution “PA-F” (Toray Industries, Inc.)
Development speed: 100 cm / min

(Examples 10-11, Comparative Examples 3-4)
Negative water-free CTP lithographic printing plate in the same manner as in Example 1 except that the amount of “DMS” -V52 added in Example 1 and the amount of colored pigment dispersion (480 hour dispersion) added were changed as follows. The original plate was prepared and evaluated.
Example 9: “DMS” -V52 = 77.84 parts by weight, colored pigment dispersion = 30.24 parts by weight Example 10: “DMS” -V52 = 74.40 parts by weight, colored pigment dispersion = 50.40 Part by weight Comparative Example 4: “DMS” -V52 = 70.96 parts by weight, colored pigment dispersion = 70.56 parts by weight Comparative Example 5: “DMS” -V52 = 67.52 parts by weight, colored pigment dispersion = 90 .72 parts by weight When the volume concentration of the colored pigment in the silicone rubber layer was 5% by volume or less, both image reproducibility and plate inspection were good. On the other hand, when the colored pigment volume concentration was 7% by volume or more, the image reproducibility was lowered. The evaluation results are summarized in Table 3.

Claims (6)

  A waterless lithographic printing plate precursor having a photosensitive or heat-sensitive layer and a silicone rubber layer containing a colored pigment on a substrate, the volume concentration of the colored pigment in the silicone rubber layer being 5% by volume or less; and A waterless lithographic printing plate precursor having an average particle diameter of a colored pigment of 400 nm or less.   The waterless lithographic printing plate precursor according to claim 1, wherein the colored pigment has an average particle size of 150 nm or less. 3. The waterless lithographic printing plate precursor according to claim 1, further comprising a pigment dispersant in the silicone rubber layer. 4. The waterless lithographic printing plate precursor as claimed in claim 3, wherein the pigment dispersant contains an organic complex compound comprising a metal and an organic compound. The waterless lithographic printing plate precursor as claimed in claim 4, wherein the metal contains titanium and / or aluminum. 4. The waterless lithographic printing plate precursor as claimed in claim 3, wherein the pigment dispersant contains an amine pigment dispersant.