JP2013221045A - Composition for forming protective film, and method of producing direct drawing waterless lithographic printing plate using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for forming a protective film capable of preventing deterioration in sensitivity to laser exposure and preventing adhesion of foreign matter to the surface of a silicone rubber layer, and a method of producing a direct drawing waterless lithographic printing plate using the composition for forming a protective film.SOLUTION: A composition for forming a protective film includes a polymer compound and a compound represented by general formula (I), wherein R is a 3-4C saturated hydrocarbon group.

Description

  The present invention relates to a protective film-forming composition and, in addition, to a method for producing a direct-drawing waterless lithographic printing plate precursor using the protective film-forming composition.

  In lithographic printing, an ink-receptive image area and an ink repellent non-image area are present on the same plane of the printing plate, and ink is applied only to the image area using the difference in ink adhesion. After that, the printing method is to transfer the ink to a printing medium such as paper. Printing plates for lithographic printing (hereinafter referred to as lithographic printing plates) include lithographic printing plates in which non-image areas are repelled by the action of dampening water, silicone rubber and fluorine without using dampening water. There is a waterless lithographic printing plate that uses a resin as an ink repellent non-image area.

  Preparation of a lithographic printing plate includes a step of exposing the lithographic printing plate precursor to form an image area and a non-image area. Various exposure methods have been proposed. These are broadly classified into a method of irradiating ultraviolet rays through an original image film and a computer-to-plate (hereinafter referred to as CTP) method in which an image is directly written from an original without using the original image film. 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. Among these methods, the method of irradiating laser light is superior to other methods in terms of resolution and plate making speed.

  There are two methods for irradiating laser light: a photon mode method using a photoreaction and a heat mode method in which photothermal conversion is performed to cause a thermal reaction. In particular, the heat mode method has become more useful due to the advantage that it can be handled in a bright room and the rapid progress of semiconductor lasers as light sources.

  Various image forming systems have been proposed so far for the direct-drawing waterless planographic printing plate precursor corresponding to such a heat mode system. For example, an imaging system that includes imaging by laser ablation that includes destructively removing or volatilizing and removing material in an imaged layer (one or more layers) (eg, patent literature). 1).

  And a first layer and a second layer attached thereto, wherein the first layer and the second layer are for at least one printing liquid selected from the group consisting of an ink and an ink repellent liquid. The first layer can be irreversibly patterned with an image-related pattern from the second layer without heating the printing member having a different affinity to substantially ablate the second layer. An image forming system to be separated; a first layer; a second layer disposed to adhere to the lower side of the first layer; and a third layer disposed to the lower side of the second layer And heating at least one of the first layer and the other layer having a different affinity for at least one printing liquid selected from the group consisting of ink and ink repellent liquid, Without ablating the second layer, the first layer Image forming system for irreversibly separated with a pattern associated with the image from the second layer and the like (e.g., see Patent Document 2).

  Furthermore, the heat-sensitive layer contains a light-to-heat conversion agent, a foaming agent, and a thermoplastic resin. The heated part expands by laser light irradiation, and the silicone rubber layer in the image line part becomes a convex state. A direct-drawing waterless lithographic printing plate precursor that can be improved is disclosed (for example, see Patent Document 3).

  Further, there is an image forming system in which at least a part of the image forming layer is solubilized and the silicone rubber layer is removed in the image formed region by using a pretreatment liquid and / or a developer (for example, (See Patent Document 4). Furthermore, as a direct-drawing waterless lithographic printing plate precursor that can be made with less laser irradiation energy and has good image reproducibility, a direct-drawing waterless lithographic printing plate precursor having bubbles and liquid bubbles in the heat-sensitive layer is disclosed. (For example, refer to Patent Documents 5 and 6).

  Since the silicone rubber layer of a waterless lithographic printing plate precursor is easily damaged, a method of laminating a cover film on the silicone rubber layer and a method of forming a polymer coating have been proposed for the purpose of protection thereof (for example, (See Patent Documents 7 to 9). On the other hand, when the exposure is performed with the cover film attached, the silicone rubber layer is hampered by the cover film, and the sensitivity is lowered. Therefore, it is proposed to perform laser exposure with the cover film peeled off. (For example, refer to Patent Document 10).

US Pat. No. 5,353,705 (Claims) US Pat. No. 6,107,001 (Claims) Japanese Patent Laid-Open No. 11-254854 (Claims, [0029] stage) JP-A-11-221977 (stage [0059]) Japanese Patent Laying-Open No. 2005-300586 (Claims) WO2010 / 113989 (Claims) JP-A-55-55343 (Claims) JP 61-27547 A (Claims) JP-A-2-301762 (Claims) JP 2000-309175 A (claims, [0120] stage)

  In the image forming systems proposed in Patent Documents 1 to 3, the method of laminating the cover film on the silicone rubber layer has a problem that the silicone rubber layer is hampered as described above and the sensitivity is lowered. Also in the direct-drawing type printing plate precursors proposed in Patent Documents 5 and 6, at least a part of the heat-sensitive layer is thermally expanded, and the silicone rubber layer is the same as the image forming system proposed in Patent Documents 1 to 3. The method of laminating the cover film on top has a problem that the sensitivity is lowered. On the other hand, when the cover film and polymer coating film proposed in Patent Documents 7 to 9 are not present when laser exposure is performed as proposed in Patent Document 10, an adhesive silicone rubber layer is formed on the printing plate. In order to become the top of the original plate, foreign materials derived from slip sheets and packaging materials contained in the printing plate original plate, its laminates and packages, or flying objects resulting from the work environment adhere to the surface of the printing plate original, and laser light Shielding the light could cause exposure inhibition. Typical examples of the foreign matters and flying objects include paper dust derived from slip sheets and packaging materials, and in addition, other dust and dust. Hereinafter, these are collectively referred to as “foreign substances”.

  The present invention relates to a protective film-forming composition capable of suppressing a decrease in sensitivity to laser exposure and suppressing adhesion of foreign matter to the surface of a silicone rubber layer, and a direct-drawing waterless lithographic printing plate precursor using the same It aims at providing the manufacturing method of. In particular, a composition for forming a protective film that contains a polymer compound that can suppress adhesion of foreign matter to the surface of the silicone rubber layer and that can easily form a protective film that is thin enough to suppress a decrease in sensitivity, and An object of the present invention is to provide a method for producing the directly drawn waterless planographic printing plate precursor used.

  In order to solve the above problems, the present invention provides a protective film-forming composition comprising a polymer compound and a compound represented by the following general formula (I).

Here, R represents a saturated hydrocarbon group having 3 to 4 carbon atoms.

  Further, a direct drawing type waterless lithographic printing plate precursor having at least a heat-sensitive layer, a silicone rubber layer and a protective film on a substrate in this order, and after forming at least the heat-sensitive layer and the silicone rubber layer on the substrate, A method for producing a direct-drawing waterless lithographic printing plate precursor, wherein the protective film-forming composition is applied onto a silicone rubber layer and then dried to form a protective film.

  With the protective film forming composition of the present invention, a protective film having a small thickness can be easily formed on the silicone rubber layer. Therefore, by using the composition for forming a protective film of the present invention, it is possible to suppress a decrease in sensitivity to laser exposure of a direct-drawing waterless lithographic printing plate precursor and to suppress foreign matter adhesion on the surface of the silicone rubber layer. it can.

  The present invention relates to a protective film forming composition and a method for producing a direct-drawing waterless lithographic printing plate precursor using the same.

  The composition for forming a protective film contains a polymer compound and a compound represented by the following general formula (I). Moreover, you may contain the crosslinking agent which has the reactivity with a high molecular compound as needed. The softening point, glass transition temperature, and hardness of the protective film can be increased by the reaction between the polymer compound and the crosslinking agent.

Here, R represents a saturated hydrocarbon group having 3 to 4 carbon atoms.

  In the present invention, the polymer compound refers to a polymer having a weight average molecular weight in the range of 10,000 to 500,000. In particular, an organic polymer (polymer) whose polymer chain is composed of carbon, hydrogen, nitrogen, oxygen, and silicon elements is preferred. Furthermore, it is preferable to dissolve in the compound represented by the general formula (I), and it is preferable that the polymer compound itself has a film forming ability. By containing the polymer compound, it is easy to produce a protective film formed from the protective film-forming composition, and sufficient film strength can be maintained. Here, the weight average molecular weight of the polymer compound can be measured by gel permeation chromatography (GPC). The weight average molecular weight of the polymer compound in the present invention is a value measured by GPC and converted to standard polystyrene.

  Examples of polymers having film-forming ability include homopolymers and copolymers of (meth) acrylic acid esters such as polymethyl (meth) acrylate and polybutyl (meth) acrylate, styrene monomers such as polystyrene and α-methylstyrene Homopolymers and copolymers of the above, homopolymers of vinyl esters such as polyvinyl acetate and copolymers such as vinyl acetate-vinyl chloride, other vinyl homopolymers and copolymers, isoprene, styrene-butadiene And other synthetic rubbers, condensation polymers such as polyester and polycarbonate, and polymers having active hydrogen in the molecule. Two or more of these may be contained. Here, (meth) acrylate indicates acrylate or methacrylate, and (meth) acrylic acid indicates acrylic acid or methacrylic acid.

Examples of the polymer having active hydrogen include —OH, —SH, —NH ₂ , —NH—, —CO—NH ₂ , —CO—NH—, —OC (═O) —NH—, —NH—CO. -NH -, - CO-OH, -CS-OH, -CO-SH, -CS-SH, -SO 3 H, -PO 3 H 2, -SO 2 -NH 2, -SO 2 -NH -, - polymers can be exemplified having a structure unit having an active hydrogen, such as _CO-CH 2 -CO-. Examples of the polymer having such a structural unit include a homopolymer or copolymer of a monomer containing a carboxyl group such as (meth) acrylic acid, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate. Homopolymers or copolymers of (meth) acrylic acid esters containing hydroxyl groups such as N-alkyl (meth) acrylamide, homopolymers or copolymers of (meth) acrylamide, amines and (meth) acrylic acid A homopolymer or copolymer of an ethylenically unsaturated monomer having active hydrogen such as a homopolymer or copolymer of a reaction product with glycidyl or allyl glycidyl, a homopolymer or copolymer of p-hydroxystyrene or vinyl alcohol Combined (active hydrogen Other ethylenically unsaturated monomers may be used, and ethylenically unsaturated monomers containing no active hydrogen may be used.), Polyurethane, polyurea, polyamide (nylon resin), epoxy resin, polyalkyleneimine, novolac resin, resole resin, Examples thereof include condensates having a structural unit having active hydrogen in the main chain such as a cellulose derivative. Two or more of these may be contained.

  In the direct-drawing waterless lithographic printing plate precursor described later, it is possible to suppress scratching of the surface of the protective film due to contact with a slip sheet or the like used as necessary, and loss of the protective film from the silicone rubber layer. It is preferable for enhancing the effect. In order to suppress the loss of the protective film due to rubbing, it is effective to improve the adhesion of the protective film to the silicone rubber layer. For the purpose of improving the adhesion between the protective film and the silicone rubber layer, a polymer containing polyorganosiloxane in the molecule is preferred as the polymer compound.

  Examples of the polymer containing polyorganosiloxane in the molecule include, for example, an acrylic polymer having a polyorganosiloxane having a radical polymerizable functional group and a polyorganosiloxane copolymerized with another radical polymerizable monomer in the side chain. A silicone graft copolymer is mentioned. As other radical polymerizable monomers, compounds having a (meth) acryloyl group and a vinyl group are preferable. Examples of the compound having a (meth) acryloyl group include methyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylamide, 2-hydroxyethyl (meth) acrylate having a hydroxyl group, and 2-hydroxypropyl (meth). Examples thereof include (meth) acrylic acid having acrylate and carboxylic acid. Examples of the compound having a vinyl group include styrene, α-methylstyrene, vinyl acetate and the like.

  From the viewpoint of maintaining the sufficient hardness of the protective film formed from the composition for forming a protective film and more stably maintaining the effect of suppressing the adhesion of foreign matter to the surface of the silicone rubber layer, the polymer having the film-forming ability is used. Among them, a polymer that forms a protective film having a softening point of 30 ° C. or higher is preferable. Furthermore, a polymer that forms a protective film having a glass transition temperature of 30 ° C. or higher is more preferable. For example, styrene, poly (α-styrene), and polyvinylpyrrolidone are polymers having a glass transition temperature of 30 ° C. or more by themselves, and are preferable polymers. In addition, “Symac (registered trademark)” US-270, GS-30, GS-101 (manufactured by Toagosei Co., Ltd.) and the like contain a polyorganosiloxane having a glass transition temperature of 30 ° C. or more alone in the molecule. And is a preferred polymer. By containing these polymers, a protective film having a glass transition temperature of 30 ° C. or higher can be formed without requiring a reaction with a crosslinking agent.

  Here, the glass transition temperature of the polymer can be determined by differential scanning calorimetry. Using about 5 mg of polymer as a measurement sample, based on JISK7121-1987, hold at -50 ° C for 5 minutes, then increase the temperature to 100 ° C at a rate of temperature increase of 20 ° C / min, and measure with a differential scanning calorimeter. The midpoint of the observed DSC curve is taken as the glass transition temperature.

  The content of the polymer compound is preferably 25% by weight or more, more preferably 50% by weight or more, based on the total solid content of the protective film-forming composition.

  Examples of the crosslinking agent having reactivity with the polymer compound include polyfunctional compounds and organic complex compounds. Examples of the polyfunctional compound include polyfunctional isocyanate, polyfunctional blocked isocyanate, polyfunctional epoxy compound, polyfunctional (meth) acrylate compound, polyfunctional aldehyde, polyfunctional mercapto compound, polyfunctional alkoxysilyl compound, polyfunctional amine. Examples thereof include compounds, polyfunctional carboxylic acids, polyfunctional vinyl compounds, polyfunctional diazonium salts, polyfunctional azide compounds, and hydrazine. Examples of the organic complex compound include an organic complex salt in which an organic ligand is coordinated to a metal, an organic inorganic complex salt in which an organic ligand and an inorganic ligand are liganded to a metal, and a metal and an organic molecule via oxygen. Examples thereof include metal alkoxides that are covalently bonded.

  The composition for forming a protective film of the present invention contains the compound represented by the general formula (I). By containing the compound represented by the general formula (I), the coating property on the surface of the silicone rubber layer is improved, and a protective film having a small thickness can be easily formed on the silicone rubber layer. Furthermore, since the solubility of the polymer compound is high, the selection range of the polymer compound is wide. Moreover, since the restrictions on the solid content concentration of the protective film-forming composition are small, an economically advantageous protective film manufacturing method can be selected.

  Specific examples of the compound represented by the general formula (I) include methyl propyl ether, n-butyl methyl ether, sec-butyl methyl ether, tert-butyl methyl ether and the like. Two or more of these may be contained. All of the compounds represented by the general formula (I) are liquid at 25 ° C. under atmospheric pressure, and act as a solvent for the polymer compound. Among the compounds represented by the general formula (I), n-butyl methyl ether and tert-butyl methyl ether are preferable from the viewpoint of coating properties and solubility, and n-butyl methyl ether is more preferable.

  The content of the compound represented by the general formula (I) in the composition for forming a protective film is preferably 50% by weight or more and 80% by weight or more from the viewpoint of coating property and solubility. More preferably, it is more preferably 90% by weight or more.

  The composition for forming a protective film of the present invention may further contain a surfactant or the like, if necessary.

  Moreover, the composition for protective film formation of this invention may use another solvent with the compound represented by the said general formula (I). The other solvent is not limited as long as it can dissolve the polymer compound and constitute the protective film-forming composition. Examples thereof include solvents such as saturated hydrocarbons, aromatic hydrocarbons, alcohols, ethers, ketones, esters and amides. The content of the compound represented by the general formula (I) in the total solvent of the composition for forming a protective film is preferably 80% by weight or more, and more preferably 95% by weight or more.

  The composition for forming a protective film of the present invention comprises a polymer compound, a compound represented by the following general formula (I), a cross-linking agent, a surfactant, and other solvents as necessary, at room temperature or under heating. And stirring and mixing.

  Next, a direct-drawing waterless lithographic printing plate precursor using the protective film-forming composition of the present invention and a method for producing the same will be described below.

  The direct-drawing waterless planographic printing plate precursor of the present invention has at least a heat-sensitive layer, a silicone rubber layer, and a protective film in this order on a substrate. When the protective film covers the surface of the silicone rubber layer, foreign matter adhesion to the silicone rubber layer is suppressed. For this reason, adhesion when a foreign material contacts the surface of the printing plate precursor can be prevented. Alternatively, in the cleaning process of the printing plate precursor surface that can be performed before the exposure process or simultaneously with the exposure process, it is easy to remove the deposits from the printing plate precursor surface. By these actions, it becomes possible to reduce the factor of exposure inhibition caused by blocking the laser beam in the exposure of the printing plate precursor. The surface of the protective film is preferably harder than the surface of the silicone rubber layer. Moreover, it is preferable that the glass transition temperature of a protective film is 30 degreeC or more.

  As the substrate, known dimensionally stable paper, metal, glass, film, etc., which have been conventionally used as a printing plate substrate, can be used. Specifically, paper; paper laminated with plastic (polyethylene, polypropylene, polystyrene, etc.); metal plate such as aluminum (including aluminum alloy), zinc, copper; glass plate such as soda lime, quartz; silicon wafer; Plastic films such as cellulose acetate, polyethylene terephthalate, polyethylene, polyester, polyamide, polyimide, polystyrene, polypropylene, polycarbonate, polyvinyl acetal; paper or plastic film on which the above metal is laminated or vapor-deposited. The plastic film may be transparent or opaque, but an opaque film is preferred from the viewpoint of plate inspection.

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

  The thickness of the substrate is not particularly limited, and a thickness corresponding to a printing machine used for lithographic printing may be selected.

  Next, the thermosensitive layer that can be preferably used in the present invention will be described. The heat-sensitive layer is preferably a layer whose physical properties change by laser drawing and / or a layer whose adhesive force with the silicone rubber layer decreases by laser drawing. For example, a layer obtained by applying a composition containing an active hydrogen-containing polymer, a crosslinking agent, a photothermal conversion substance, or an active hydrogen-containing polymer, an organic complex compound, or a photothermal conversion substance, and drying (heating). Can be mentioned.

  As the polymer having active hydrogen, those exemplified as the polymer having active hydrogen in the polymer compound contained in the composition for forming a protective film can be used. Two or more of these may be contained. Among them, a polymer having an alcoholic hydroxyl group, a phenolic hydroxyl group, or a carboxyl group is preferable, and a polymer having a phenolic hydroxyl group (such as a homopolymer or copolymer of p-hydroxystyrene, a novolak resin, or a resole resin) is more preferable.

  The content of the polymer having active hydrogen is preferably 50% by weight to 90% by weight in the total solid content of the heat-sensitive layer.

  It is also preferable to contain a polymer having active hydrogen and a film-forming polymer that does not have active hydrogen (referred to as another polymer). Other polymers include homopolymers or copolymers of (meth) acrylic acid esters such as polymethyl (meth) acrylate and polybutyl (meth) acrylate, homopolymers of styrene monomers such as polystyrene and α-methylstyrene, or Copolymers, various synthetic rubbers such as isoprene and styrene-butadiene, homopolymers such as vinyl esters such as polyvinyl acetate, copolymers such as vinyl acetate-vinyl chloride, various condensation polymers such as polyester and polycarbonate, etc. Is mentioned.

  The content of these other polymers is preferably 30% by weight or less, more preferably 10% by weight or less, based on the total solid content of the heat-sensitive layer.

  Examples of the crosslinking agent include known polyfunctional compounds having crosslinkability. For example, what was illustrated as a polyfunctional compound in the crosslinking agent which may be contained in the composition for protective film formation can be used.

  The organic complex compound is composed of a metal and an organic compound, and functions as a crosslinking agent for a polymer having active hydrogen and / or as a catalyst for a thermosetting reaction. Even when the organic complex compound functions as a cross-linking agent, the heat-sensitive layer may further contain the above-described cross-linking agent.

  Examples of the organic complex compound in the present invention include an organic complex salt in which an organic ligand is coordinated to a metal, an organic inorganic complex salt in which an organic ligand and an inorganic ligand are liganded to a metal, and a metal and an organic molecule through oxygen. Metal alkoxides covalently bonded to each other. Among these, the metal chelate compound in which the ligand has two or more donor atoms and forms a ring containing a metal atom, the stability of the organic complex compound itself, the stability of the thermosensitive layer composition solution, etc. It is preferably used from the aspect of.

  The main metals forming the organic complex compounds are Al (III), Ti (IV), Mn (II), Mn (III), Fe (II), Fe (III), Co (II), Co (III ), Ni (II), Ni (IV), Cu (I), Cu (II), Zn (II), Ge, In, Sn (II), Sn (IV), Zr (IV), Hf (IV) Is preferred. Al (III) is particularly preferable from the viewpoint that the effect of improving the sensitivity is easily obtained, and Ti (IV) is particularly preferable from the viewpoint that resistance to the printing ink and the ink cleaning agent is easily exhibited.

Moreover, as a ligand, the compound which has a coordination group which has oxygen, nitrogen, sulfur, etc. as a donor atom is mentioned. Specific examples of the coordinating group include oxygen 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-oxide), Examples of —SO ₃ H (sulfonic acid) and —PO ₃ H ₂ (phosphorous acid) that use nitrogen as a donor atom include —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 compounds ),> C = N- ( Examples of compounds having sulfur as a donor atom, such as Cuff base, heterocyclic compound),> C = NH (aldehyde, ketone imine, enamines), -NCS (isothiocyanato), -SH (thiol), -S- (thioether) ),> C = S (thioketone, thioamide), = S- (heterocyclic compound), -C (= O) -SH, -C (= S) -OH, -C (= S) -SH (thiocarboxylic acid) ), -SCN (thiocyanato) and the like.

  Among the organic complex compounds formed from the above metals and ligands, the compounds preferably used include Al (III), Ti (IV), Fe (II), Fe (III), and Mn (III). , Co (II), Co (III), Ni (II), Ni (IV), Cu (I), Cu (II), Zn (II), Ge, In, Sn (II), Sn (IV), Zr (IV), Hf (IV) and other metal β-diketones, amines, alcohols, complex compounds with carboxylic acids, Al (III), Fe (II), Fe (III), Ti Particularly preferred are (IV), acetylacetone complexes of Zr (IV), acetoacetate complexes, and the like.

  Specific examples of such compounds include the following compounds. Aluminum tris (acetylacetonate), aluminum tris (ethyl acetoacetate), aluminum tris (propyl acetoacetate), aluminum tris (butyl acetoacetate), aluminum tris (hexyl acetoacetate), aluminum tris (nonyl acetoacetate), aluminum tris (Hexafluoropentadionate), aluminum tris (2,2,6,6-tetramethyl-3,5-heptanedionate), aluminum bis (ethyl acetoacetate) mono (acetylacetonate), aluminum bis (acetylacetate) Nate) mono (ethyl acetoacetate), aluminum bis (propyl acetoacetate) mono (acetylacetonate), aluminum bis (butyl acetoacetate) G) Mono (acetylacetonate), aluminum bis (hexyl acetoacetate) mono (acetylacetonate), aluminum bis (propyl acetoacetate) mono (ethyl acetoacetate), aluminum bis (butyl acetoacetate) mono (ethyl acetoacetate) Aluminum bis (hexyl acetoacetate) mono (ethyl acetoacetate), Aluminum bis (nonyl acetoacetate) mono (ethyl acetoacetate), Aluminum dibutoxide mono (acetylacetonate), Aluminum diisopropoxide mono (acetylacetonate) Aluminum diisopropoxide mono (ethyl acetoacetate), aluminum-s-butoxide bis (ethyl acetoacetate), aluminum di-s- Tokishidomono (ethylacetoacetate), aluminum di-isopropoxide mono (9-octadecenyl acetoacetate), etc.. Titanium triisopropoxide mono (allyl acetoacetate), titanium diisopropoxide bis (triethanolamine), titanium di-n-butoxide bis (triethanolamine), titanium diisopropoxide bis (acetylacetonate), titanium Di-n-butoxide bis (acetylacetonate), titanium diisopropoxide bis (2,2,6,6-tetramethyl-3,5-heptanedionate), titanium diisopropoxide bis (ethyl acetoacetate) Titanium di-n-butoxide bis (ethyl acetoacetate), titanium tri-n-butoxide mono (ethyl acetoacetate), titanium triisopropoxide mono (methacryloxyethyl acetoacetate), titanium oxide Dobisu (acetylacetonate), titanium tetra (2-ethyl-3-hydroxyhexyl oxide), titanium dihydroxy bis (lactate), and titanium (ethylene glycolate) bis (dioctyl phosphate). Zirconium di-n-butoxide bis (acetylacetonate), zirconium tetrakis (hexafluoropentanedionate), zirconium tetrakis (trifluoropentanedionate), zirconium tri-n-propoxide mono (methacryloxyethylacetoacetate), zirconium Tetrakis (acetylacetonate), zirconium tetrakis (2,2,6,6-tetramethyl-3,5-heptanedionate), triglycolate zirconate, trilactate zirconate and the like. Iron (III) acetylacetonate, dibenzoylmethane iron (II), tropolone iron, tristroporono iron (III), hinokitiol iron, tris hinokitioro iron (III), acetoacetate iron (III), iron (III) benzoyl Acetonate, iron (III) diphenylpropane dionate, iron (III) tetramethylheptane dionate, iron (III) trifluoropentane dionate, etc. Two or more of these may be contained.

  The content of such an organic complex compound is preferably 3 to 30% by weight in the total solid content of the heat-sensitive layer. By making the content of the organic complex compound 3% by weight or more, the above effects can be further enhanced. On the other hand, when the content is 30% by weight or less, high printing durability of the printing plate can be maintained.

  The photothermal conversion substance is not particularly limited as long as it absorbs laser light, and pigments and dyes that absorb infrared rays or near infrared rays are preferable. For example, black pigments such as carbon black, carbon graphite, aniline black, cyanine black, phthalocyanine, naphthalocyanine-based green pigment, crystal water-containing inorganic compounds, iron, copper, chromium, bismuth, magnesium, aluminum, titanium, zirconium, cobalt , Metal powders such as vanadium, manganese and tungsten, or sulfides, hydroxides, silicates, sulfates, phosphates, diamine compound complexes, dithiol compound complexes, phenolthiol compound complexes, mercaptophenol compound complexes of these metals, etc. Can be mentioned.

  In addition, as dyes that absorb infrared rays or near infrared rays, they are dyes for electronics and recording, and cyanine dyes, azurenium dyes, squarylium dyes, croconium dyes, azo dyes having a maximum absorption wavelength in the range of 700 nm to 1500 nm. Disperse dyes, bisazostilbene dyes, naphthoquinone dyes, anthraquinone dyes, perylene dyes, phthalocyanine dyes, naphthalocyanine metal complex dyes, polymethine dyes, dithiol nickel complex dyes, indoaniline metal complex dyes, molecules Intercalated CT dyes, benzothiopyran spiropyrans, nigrosine dyes and the like are preferably used.

Among these dyes, those having a large molar absorbance coefficient ε are preferably used. Specifically, ε is preferably 1 × 10 ⁴ or more, more preferably 1 × 10 ⁵ or more. If ε is 1 × 10 ⁴ or more, the initial sensitivity can be further improved.

  You may contain 2 or more types of these photothermal conversion substances. By containing two or more kinds of photothermal conversion substances having different absorption wavelengths, it is possible to cope with two or more kinds of lasers having different emission wavelengths.

  Among these, carbon black, dyes that absorb infrared rays or near infrared rays are preferable from the viewpoint of photothermal conversion, economic efficiency, and handleability.

  The content of these photothermal conversion substances is preferably 0.5 to 40% by weight in the total solid content of the heat-sensitive layer. By setting the content of the photothermal conversion substance to 0.5% by weight or more, the sensitivity to laser light can be further improved. On the other hand, when the content is 40% by weight or less, high printing durability of the printing plate can be maintained.

  In the direct-drawing waterless planographic printing plate precursor of the present invention, the heat-sensitive layer may contain various additives as necessary. For example, a silicone surfactant or a fluorine surfactant may be contained in order to improve the coating property. Further, a silane coupling agent, a titanium coupling agent, or the like may be contained in order to enhance the adhesiveness with the silicone rubber layer. The content of these additives varies depending on the purpose of use, but is generally 0.1 to 30% by weight in the total solid content of the heat-sensitive layer.

  For the purpose of increasing sensitivity, the direct-drawing waterless lithographic printing plate precursor of the present invention may have bubbles in the heat-sensitive layer. Examples of the method for forming bubbles in the heat-sensitive layer include the methods described in JP-A-2005-300586 and JP-A-2005-331924.

  Furthermore, for the purpose of maintaining high sensitivity even after lapse of time in addition to high sensitivity immediately after the original plate is produced, the direct-drawing waterless lithographic printing plate precursor of the present invention may have liquid bubbles in the heat-sensitive layer. . More preferably, the heat-sensitive layer has liquid bubbles containing a liquid having a boiling point in the range of 210 to 270 ° C. Examples of the method for forming liquid bubbles in the heat sensitive layer include the method described in Japanese Patent No. 4807472.

  When the heat-sensitive layer has bubbles or liquid bubbles, at least a part of the heat-sensitive layer thermally expands, so that the method of laminating the cover film on the silicone rubber layer has a problem that the sensitivity is lowered. By forming the protective film of the present invention, a highly sensitive direct-drawing waterless lithographic printing plate precursor in which foreign matter adhesion to the surface of the silicone rubber layer is suppressed can be obtained.

  The highly sensitive direct-drawing waterless lithographic printing plate precursor having bubbles and liquid bubbles can be developed by simply applying a physical force after exposure. For this reason, in the process of producing a waterless lithographic printing plate by exposing a direct-drawing waterless lithographic printing plate precursor, a phenomenon called “blowing” may occur in which the silicone rubber layer in the exposed area is lifted. When a “fire blistering” phenomenon occurs, when the direct-drawing waterless lithographic printing plate precursor after exposure is transported, the lifted silicone rubber layer is undesirably transferred to the transport roller in the exposure machine or automatic processor. There is a case. The silicone rubber layer transferred to the transport roller is retransferred to the plate surface of the next plate to be processed, which causes exposure inhibition and development inhibition. This blistering phenomenon is more likely to occur as the direct-drawing waterless lithographic printing plate precursor has higher sensitivity. Also, the blistering phenomenon is more likely to occur as the exposure amount increases.

  In order to suppress the above-mentioned blistering phenomenon, the heat-sensitive layer contains non-photosensitive particles, and the average particle diameter of the non-photosensitive particles is ½ of the average heat-sensitive layer thickness of the portion where the non-photosensitive particles are not present. A heat-sensitive layer having a phase separation structure having at least a novolac resin, polyurethane, and a photothermal conversion substance, and having a phase containing at least a novolak resin and a phase containing polyurethane may be used. .

  In the case where the heat-sensitive layer contains non-photosensitive particles, the average particle diameter of the non-photosensitive particles is preferably 1/2 times or more of the heat-sensitive layer average film thickness of the portion where the non-photosensitive particles are not present, and 3/4 The above is more preferable, 1 times or more is more preferable, and 5/4 times or more is further preferable. By making the average particle diameter of the non-photosensitive particles at least 1/2 times the average thickness of the heat-sensitive layer in the portion where the non-photosensitive particles are not present, the effect of improving the blister resistance is further improved. On the other hand, from the viewpoint of suppressing scumming in the non-image area at the time of printing due to non-photosensitive particles, the average particle diameter of the non-photosensitive particles is a portion of the heat-sensitive layer and the silicone rubber where no non-photosensitive particles exist. It is preferable that it is below the total average film thickness of a layer.

  In the present invention, the particle diameter of the non-photosensitive particles refers to an equivalent volume sphere equivalent diameter when the particles are assumed to be true spheres. The average particle size of the non-photosensitive particles refers to a number average value calculated from a plurality of particles having the above particle sizes. The average particle diameter of the non-photosensitive particles contained in the heat-sensitive layer can be determined by observation with a transmission electron microscope (TEM). More specifically, a sample is prepared from a direct-drawing waterless lithographic printing plate precursor by a continuous (ultra-thin) section method, and TEM observation of the thermosensitive layer is performed under the conditions of an acceleration voltage of 100 kV and a magnification of 2000 times. The average particle diameter can be obtained by measuring the particle diameter of 50 randomly selected non-photosensitive particles based on the three-dimensional information of the horizontal section and calculating the number average value thereof. A method for measuring the average film thickness of the silicone rubber layer will be described later.

  In the direct-drawing waterless planographic printing plate precursor of the present invention, the average film thickness of the heat-sensitive layer in the portion where non-photosensitive particles are not present is preferably 0.3 μm or more, more preferably 0.8 μm or more. On the other hand, it is preferably 10 μm or less, and more preferably 7 μm or less. When the average film thickness of the heat-sensitive layer where the non-photosensitive particles are not present is 0.3 μm or more, the developability is hardly lowered, and when it is 10 μm or less, the effect of improving the blister resistance is easily exhibited. It is not disadvantageous from an economic point of view. Here, the average film thickness of the heat-sensitive layer where no non-photosensitive particles are present can be determined by TEM observation. More specifically, a sample is prepared from a direct-drawing waterless lithographic printing plate precursor by an ultrathin section method, and TEM observation is performed under the conditions of an acceleration voltage of 100 kV and a magnification of 2000 times. In a TEM photograph of a vertical cross section, the film thickness was measured at 10 locations randomly selected from the heat-sensitive layer in a smooth portion without non-photosensitive particles, and the average film thickness was calculated by calculating the number average value thereof. Can be sought.

  The non-photosensitive particles in the present invention refer to particles that do not absorb at least light in the near-infrared region (700-1500 nm) used for exposure, and have carbon black and other photothermal conversion capabilities. Clearly different from pigments. The presence of non-photosensitive particles contained in the heat-sensitive layer can be observed morphologically by observing the vertical and horizontal cross sections of the heat-sensitive layer using an analytical instrument such as TEM.

  As the kind of non-photosensitive particles, whether they are inorganic particles, organic particles, or inorganic / organic hybrid particles, the effect of improving the blister resistance of the present invention is exhibited. Two or more of these may be included.

Examples of the inorganic particles include non-photosensitive inorganic particles such as SiO ₂ , Al ₂ O ₃ , TiO ₂ , SnO ₂ , Sb ₂ O ₅ , Fe ₂ O ₃ , ZrO ₂ , CeO ₂ , and Y ₂ O _3. It is done. Among these, silica particles are preferable.

  Organic particles include (meth) acrylic acid, (meth) acrylic acid derivatives, styrene, vinyl acetate, acrylonitrile, olefin polymers, copolymers thereof, polyester, polyamide, latex, polyurethane, phenolic resin, benzoguanamine, Non-photosensitive organic particles such as melamine resin, polyethersulfone resin, silicone resin, cellulose, fluororesin, poly (fluoromethyl methacrylate) and the like can be mentioned. Here, (meth) acrylic acid is a general term for acrylic acid and methacrylic acid. Among these, (meth) acrylic acid and / or (meth) acrylic acid derivatives, styrene polymers, copolymers thereof, and silicone resins are preferable.

  Further, as the organic particles, core-shell type non-photosensitive organic particles having a core-shell structure in which different organic components constitute a core part and a shell part, respectively, can be used.

  Since these non-photosensitive particles are usually used by being dispersed in the heat-sensitive layer composition solution, it is preferable that the non-photosensitive particles have excellent dispersion stability in the heat-sensitive layer composition solution and are not likely to spontaneously settle. Among the above-mentioned non-photosensitive particles, organic particles generally have a smaller density than inorganic particles, and are more preferable in terms of dispersion stability in the heat-sensitive layer composition solution.

  The non-photosensitive particles are preferably insoluble in the heat-sensitive layer composition solution. In general, inorganic particles are difficult to dissolve in an organic solvent, but uncrosslinked organic particles may be dissolved in an organic solvent. Therefore, when organic particles are used, it is preferable to use organic particles having a crosslinked structure, and polymers having a crosslinked structure of (meth) acrylic acid, (meth) acrylic acid derivatives, styrene, vinyl acetate, acrylonitrile, and olefins. And copolymers having these crosslinked structures, crosslinked polyesters, crosslinked polyamides, crosslinked latexes, crosslinked polyurethanes, crosslinked phenol resins, crosslinked benzoguanamine / melamine resins, crosslinked polyethersulfone resins, crosslinked silicone resins, crosslinked cellulose, and crosslinked fluorine resins. And non-photosensitive organic particles such as crosslinked poly (fluoromethyl methacrylate).

  As the shape of the non-photosensitive particles, spherical, hemispherical, irregular spherical, middle concave spherical, flat shape, lens shape, cubic shape, columnar shape, plate shape, flake shape, granular shape, rod shape, needle shape, fibrous shape, lump shape, A dendritic shape, a spongy shape, a square shape, a horn shape, a round shape, and the like can be mentioned, and any shape exhibits an effect of improving the blister resistance. Among these, spherical particles are particularly preferable in that they have no directivity unlike other shapes, and thus the effect of improving the blister resistance can be stably expressed.

  As the particle size of the non-photosensitive particles, it is preferable to use particles having a narrow distribution and close to monodispersion. A CV (Coefficient of Variation) value (CV value [%] = (standard deviation / average particle size) × 100) is generally used as an index representing the monodispersity of particles. The CV value of the conductive particles is preferably 15% or less, more preferably 10% or less, and further preferably 5% or less. When the CV value of the non-photosensitive particles is 15% or less, the blister resistance can be more effectively improved even if the content of the non-photosensitive particles is small.

  The CV value of the non-photosensitive particles can be determined by using a general laser diffraction / scattering particle size distribution analyzer (for example, “SALD (registered trademark)” series (manufactured by Shimadzu Corporation)) or dynamic light scattering particle size distribution. It is obtained from the above formula from the average particle diameter and standard deviation measured using a measuring device (for example, “LB” series (manufactured by Horiba, Ltd.)). In the case of spherical non-photosensitive particles, an image is taken with a digital camera connected to a transmission optical microscope (preferably an objective lens with a magnification of 100 times or more) (total magnification on the monitor is 2000 times). The average particle diameter and standard deviation are measured by image analysis measurement software (for example, “WinROOF” (manufactured by Mitani Corp.)) and applied to the above formula to obtain the CV value. The CV value of the non-photosensitive particles in the direct-drawing waterless lithographic printing plate precursor is the equivalent volume sphere equivalent diameter of 50 or more non-photosensitive particles obtained by the particle size measuring method of the non-photosensitive particles described above. From the above information, the number average particle diameter and the standard deviation are calculated, and these values are applied to the above formula. If the same non-photosensitive particles are used, the CV value is the same regardless of whether the non-photosensitive particles or the direct-drawing waterless planographic printing plate precursor is used.

  In addition, for the purpose of improving the dispersibility of the non-photosensitive particles in the heat-sensitive layer composition solution, improving the affinity with other components, and securing the cross-linking point, the surface of the non-photosensitive particles has a carboxyl group, a hydroxyl group, and an epoxy. A functional group such as a group, glycidyl group, acryloyl group, methacryloyl group, vinyl group or allyl group may be introduced.

  In the direct-drawing waterless planographic printing plate precursor of the present invention, the in-plane occupation ratio of the non-photosensitive particles in the heat-sensitive layer is preferably 40 area% or less, and 30 area% or less in the total area (100 area%) of the heat-sensitive layer. Is more preferable. If the non-photosensitive particle occupancy is 40 area% or less, the non-photosensitive particles are unlikely to overlap in the depth direction of the heat-sensitive layer, thereby preventing exposure inhibition during exposure and non-image area smearing during printing. can do. On the other hand, from the viewpoint of further improving the blistering resistance, the in-plane occupation ratio of the non-photosensitive particles is preferably 0.5 area% or more, and more preferably 1.0 area% or more. Here, the in-plane occupation ratio of the non-photosensitive particles in the heat-sensitive layer refers to a ratio (area%) of the non-photosensitive particles in an arbitrary horizontal section of the heat-sensitive layer. The in-plane occupation ratio of the non-photosensitive particles in the heat-sensitive layer can be obtained by TEM observation. More specifically, a sample is prepared from a direct-drawing waterless lithographic printing plate precursor by a continuous (ultra-thin) section method, and a TEM observation of the horizontal section of the thermosensitive layer is performed under the conditions of an acceleration voltage of 100 kV and a magnification of 2000 times. By calculating the area occupied by the non-photosensitive particles in the unit area, the in-plane occupancy ratio (area%) of the non-photosensitive particles can be obtained.

  When the heat-sensitive layer of the direct-drawing waterless lithographic printing plate precursor of the present invention has a phase separation structure of at least a phase containing a novolac resin and a phase containing a polyurethane, the heat-sensitive layer contains (A) a novolak resin, ( B) It contains at least polyurethane and (C) a photothermal conversion substance, and may further contain (D) an organic complex compound. Part or all of the polymer having active hydrogen may be replaced with (A) a novolak resin and (B) polyurethane.

(A) Novolak resin As an example of the novolak resin used in the direct-drawing waterless printing plate precursor of the present invention, it is obtained by reacting the phenols exemplified below with the aldehydes exemplified below under an acidic catalyst. And novolak resin.

  Examples of the phenols include phenol; cresols such as m-cresol, p-cresol, o-cresol; 2,3-xylenol, 2,5-xylenol, 3,5-xylenol, 3,4-xylenol, and the like. Xylenols; alkylphenols; alkoxyphenols; isopropenylphenols; arylphenols; polyhydroxyphenols and the like. These may be used alone or in combination of two or more. Among these phenols, phenol or o-cresol is preferable.

  Examples of the aldehydes include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, and the like. These may be used alone or in combination of two or more. Of these aldehydes, formaldehyde is preferred.

  As the acidic catalyst, hydrochloric acid, sulfuric acid, formic acid, oxalic acid, p-toluenesulfonic acid and the like can be used.

  Among the above-mentioned novolak resins, phenol novolak resins or o-cresol novolak resins are preferable.

  The weight average molecular weight of the novolak resin is preferably 5000 or less, and more preferably 4000 or less. By using a novolak resin having a weight average molecular weight of 5000 or less, cross-linking at the time of laser irradiation becomes easy, and the sensitivity can be further improved. On the other hand, the weight average molecular weight of the novolak resin is preferably 500 or more, and more preferably 800 or more. By using a novolak resin having a weight average molecular weight of 500 or more, the adhesion between the heat-sensitive layer and the silicone rubber layer is improved. In the present invention, the weight average molecular weight of the novolak resin is determined by the GPC method. The weight average molecular weight in the present invention is a value converted with standard polystyrene.

  The content of the novolak resin is preferably 20 to 87% by weight in the total solid content of the heat sensitive layer from the viewpoint of coatability. The lower limit is more preferably 50% by weight or more, and the upper limit is more preferably 85% by weight or less.

(B) Polyurethane Examples of the polyurethane used in the direct-drawing waterless printing plate precursor of the present invention include polyurethanes obtained from polyisocyanates and polyhydric alcohols exemplified below. The polyurethane may be linear or branched, and may have various functional groups such as hydroxyl groups. Two or more of these may be contained.

  As the polyisocyanate, aromatic polyisocyanate, alicyclic polyisocyanate or aliphatic polyisocyanate can be used. Aromatic polyisocyanates are preferred.

  Aromatic polyisocyanates include paraphenylene diisocyanate, 2,4- or 2,6-toluylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), tolidine diisocyanate (TODI), xylylene diene An isocyanate (XDI) etc. are illustrated. Two or more of these may be used.

  Examples of the aliphatic or alicyclic polyisocyanate include hexamethylene diisocyanate, isophorone diisocyanate, norbornane diisocyanate, hydrogenated diphenylmethane diisocyanate, and hydrogenated m-xylene diisocyanate. Two or more of these may be used.

  In addition, modified products and derivatives of the polyisocyanate can be used. Examples of such a modified product or derivative include a urethane-modified product that is a reaction product of polyisocyanate and alcohol; a dimer (also known as uretidione) or a trimer as a reaction product of two or three polyisocyanates. (Also known as isocyanurate); polycarbodiimide produced by decarbonation gas; or allophanate modified, burette modified, urea modified, etc., which are reaction products with polyisocyanate, alcohol, amine compound, etc .; Can be mentioned.

  The polyisocyanate is preferably at least 50 mol% aromatic polyisocyanate, more preferably all aromatic polyisocyanate. When the aromatic polyisocyanate is 50 mol% or more, the direct-drawing waterless lithographic printing plate precursor has high sensitivity and hardly causes blistering.

  Polyhydric alcohols can be broadly classified into polyether polyols, polyester polyols, and others.

  Specific examples of the polyether polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butylene glycol, 1,5-pentanediol, and 1,6-hexane. Examples include diol, diethylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, p-xylylene glycol, hydrogenated bisphenol A, and bisphenol dihydroxypropyl ether.

  Polyester polyols can be further classified into condensed polyester polyols, lactone polyester polyols, polycarbonate polyols and the like.

  The condensed polyester polyol is obtained by dehydration condensation of a polyvalent carboxylic acid and its anhydride and glycol and / or triol.

  Examples of polycarboxylic acids and polycarboxylic anhydrides include phthalic anhydride, isophthalic acid, terephthalic acid, succinic anhydride, adipic acid, azelaic acid, sebacic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrabromo Examples thereof include phthalic anhydride, tetrachlorophthalic anhydride, het acid anhydride, hymic anhydride, maleic anhydride, fumaric acid, itaconic acid, trimellitic anhydride, methylcyclohexeric carboxylic anhydride, pyromellitic anhydride, and the like.

  Specific examples of condensed polyester polyols include polyethylene adipate, polypropylene adipate, polyhexamethylene adipate, polyneopentyl adipate, polyhexamethylene neopentyl adipate, polyethylene hexamethylene adipate, polytetramethylene adipate, etc. Can do.

  Examples of the lactone polyester polyol include those obtained by ring-opening polymerization of lactones such as β-propiolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone.

  Examples of the polycarbonate polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, and the like. Ring opening polymer of ethylene carbonate with molecular weight polyol as initiator, for example, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, etc. An amorphous polycarbonate polyol obtained by copolymerizing a dihydric alcohol and a ring-opening polymer of ethylene carbonate.

  Other polyhydric alcohols include, for example, an acrylic polyol that is a copolymer of an acrylic (or methacrylic) monomer having a hydroxyl group such as β-hydroxyethyl methacrylate and an acrylic (or methacrylic acid) ester, and a hydroxyl group at the end. Examples thereof include butanediene and polybutadiene polyol which is a copolymer thereof, partially saponified ethylene vinyl acetate copolymer (EVA), and the like. Furthermore, various phosphorus-containing polyols, halogen-containing polyols, phenol-based polyols and the like can be mentioned.

  As the polyhydric alcohol, a polyester polyol is preferable, and among the polyester polyols, a condensed polyester polyol and a lactone polyester polyol are preferable.

  In the present invention, the phase separation structure of the heat sensitive layer can be formed by utilizing the difference in solubility between the novolac resin and polyurethane. In particular, it has been experimentally clarified that by using polyurethane having a heat softening point of 200 ° C. or more, a phase-separated structure can be easily formed between a phase mainly composed of novolac resin and a phase mainly composed of polyurethane. It has become.

  Here, the heat softening point of polyurethane can be measured based on JIS-K 7210 (1999) using Koka-type flow tester CFT-500D (manufactured by Shimadzu Corporation). While heating 1 g of a measurement sample at a temperature rising temperature of 6 ° C./min, a load of 1.96 MPa was applied by a plunger, extruded from a nozzle having a diameter of 1 mm and a length of 1 mm, and a plunger descending amount-temperature curve was drawn. The softening point is defined as a temperature corresponding to ½ of the maximum value of the plunger drop (the temperature when half of the measurement sample flows out).

  The total content of the novolak resin and polyurethane in the total solid content of the heat-sensitive layer is preferably 25% by weight or more, more preferably 55% by weight or more, and 70% by weight or more. Further preferred. If the total content of novolac resin and polyurethane is 25% by weight, a phase separation structure is easily formed.

  The content of polyurethane in the total solid content of the heat-sensitive layer is preferably 5% by weight or more in the total solid content of the heat-sensitive layer from the viewpoint of forming a phase separation structure. On the other hand, from the viewpoint of maintaining higher sensitivity, it is preferably 30% by weight or less, more preferably 20% by weight or less, based on the total solid content of the heat-sensitive layer.

  The polyurethane content is preferably 8% by weight or more, more preferably 10% by weight or more, based on the total of the novolak resin and the polyurethane, in order to suppress blistering. Moreover, it is preferable that the polyurethane is 25% by weight or less based on the total of the novolak resin and the polyurethane in order to make the direct-drawing waterless lithographic printing plate precursor highly sensitive.

  The phase separation structure of the heat-sensitive layer can be observed by observing the heat-sensitive layer of the direct-drawing waterless lithographic printing plate precursor with a magnification of 1000 using an optical microscope. For example, an optical microscope: “ECLIPSE” L200 (manufactured by Nikon Corporation, transmission mode, objective lens: “CFI LU Plan Apo EPI” 50 × (manufactured by Nikon Corporation)) Digital camera connected to: “DXM” 1200F (manufactured by Nikon Co., Ltd.), taking an image with a resolution of 1080 × 1280 pixels (total magnification on monitor: 1000 ×, observation field of view 180 × 240 μm) The separation structure can be observed. At this time, it was determined that the phase separation structure was formed when each phase separation structure had a linear size of 1 μm or more in any direction. Observe the sample with the heat-sensitive layer exposed, as observation with an optical microscope with a silicone rubber layer laminated on the heat-sensitive layer may cause a lot of noise and make it difficult to observe the phase separation structure. Is preferred.

  The size of the individual phases of the phase separation structure can be controlled by selecting the compatibility between polyurethane and other components in the heat sensitive layer. It can also be controlled by selecting a method for forming the heat-sensitive layer. When applying a method for producing a heat-sensitive layer by applying a heat-sensitive layer composition solution containing a heat-sensitive layer constituent component to a substrate and then drying, the individual phases of the phase separation structure can be selected by selecting the solution concentration and the drying speed. The size can be controlled.

  By controlling the size of the individual phases of the phase separation structure, it is possible to achieve both blistering resistance and high-definition image formation. In this case, the area ratio of the phase containing a relatively large amount of polyurethane in the entire observation field of the optical microscope is preferably 50% by area or less. On the other hand, from the viewpoint of further improving the blister resistance, the in-plane occupation ratio of the phase containing a relatively large amount of polyurethane is preferably 5 area% or more, and more preferably 10 area% or more.

  The phase separation structure of the heat sensitive layer can also be observed by observation with a transmission electron microscope (TEM). More specifically, a phase separation structure is obtained by preparing a sample from a direct-drawing waterless lithographic printing plate precursor by a continuous (ultra-thin) section method and performing TEM observation of the thermosensitive layer under the conditions of an acceleration voltage of 100 kV and a magnification of 15000 times. Can be confirmed. This observation method is useful when using a sample in which a silicone rubber layer is laminated on a heat sensitive layer.

  In the direct-drawing waterless planographic printing plate precursor of the present invention, the average thickness of the heat-sensitive layer is preferably 0.3 μm or more, and more preferably 0.8 μm or more. On the other hand, it is preferably 10 μm or less, and more preferably 7 μm or less. When the average thickness of the heat-sensitive layer is 0.3 μm or more, the developability is hardly lowered, and when it is 10 μm or less, the effect of improving the blister resistance is easily exhibited, and this is not disadvantageous from an economical viewpoint.

  In the direct-drawing waterless planographic printing plate precursor of the present invention, as the silicone rubber layer, a layer obtained by applying an addition reaction type silicone rubber layer composition or a condensation reaction type silicone rubber layer composition, Examples include a layer obtained by applying a solution and (heating) drying.

  The addition reaction type silicone rubber layer composition preferably contains at least a vinyl group-containing organopolysiloxane, a SiH group-containing compound (addition reaction type crosslinking agent) and a curing catalyst. Furthermore, you may contain reaction inhibitor.

  The vinyl group-containing organopolysiloxane 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. Two or more of these may be contained. From the viewpoint of ink repellency of the printing plate, it is preferred that 50 mol% or more of the substituents bonded to the main chain are methyl groups. 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 a diorganohydrogensilyl group, and organohydrogenpolysiloxanes are preferred. Two or more of these may be contained.

  Organohydrogenpolysiloxane has a linear, cyclic, branched, and network molecular structure, with both molecular chain terminal trimethylsiloxy group-capped polymethylhydrogensiloxane and molecular chain both terminal trimethylsiloxy group-capped dimethylsiloxane methyl. Hydrogen siloxane copolymer, trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer, molecular chain dimethylhydrogensiloxy group-capped dimethylpolysiloxane, molecular chain both-end dimethylhydro Examples include a dimethylsiloxy group-blocked dimethylsiloxane / methylphenylsiloxane copolymer, a molecular chain both-end dimethylhydrogensiloxy group-blocked methylphenylpolysiloxane, and the like.

  Examples of the organic polymer having a diorganohydrogensilyl group include dimethylhydrogensilyl group-containing (meth) acrylic monomers such as dimethylhydrogensilyl (meth) acrylate, dimethylhydrogensilylpropyl (meth) acrylate, and ( Methyl) methacrylate, ethyl (meth) acrylate, butyl (meth) acrylate, ethyl hexyl (meth) acrylate, lauryl (meth) acrylate, styrene, α-methylstyrene, maleic acid, vinyl acetate, allyl acetate, etc. And oligomers obtained by copolymerization with the above 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 rubber layer composition 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 and unsaturated alcohols, and acetylene group-containing alcohols are preferably used. Two or more of these may be contained. 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 rubber layer composition, from the viewpoint of the stability of the silicone rubber layer composition or its solution. Further, from the viewpoint of curability of the silicone rubber layer, the content is preferably 20% by weight or less, more preferably 15% by weight or less in the silicone rubber layer composition.

  The curing catalyst is selected from known ones. Preferred are platinum compounds, and specific examples include platinum alone, platinum chloride, chloroplatinic acid, olefin coordinated platinum, platinum alcohol-modified complexes, platinum methylvinylpolysiloxane complexes, and the like. Two or more of these may be contained. 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 rubber layer composition from the viewpoint of curability of the silicone rubber layer. Further, from the viewpoint of the stability of the silicone rubber layer composition and the solution thereof, the content is preferably 20% by weight or less, more preferably 15% by weight or less in the silicone rubber layer composition.

  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 composition preferably contains at least a hydroxyl group-containing organopolysiloxane, a crosslinking agent and a curing catalyst.

  The hydroxyl group-containing organopolysiloxane 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. Two or more of these may be contained.

  Examples of the crosslinking agent include silicon compounds such as a deacetic acid type, a deoxime type, a dealcohol type, a deacetone type, a deamide type, and a dehydroxylamine type.

  Specific compounds include methyltriacetoxysilane, ethyltriacetoxysilane, vinyltriacetoxysilane, allyltriacetoxysilane, phenyltriacetoxysilane, tetraacetoxysilane and other acetoxysilanes, vinylmethylbis (methylethylketoximino) silane , Methyl tris (methyl ethyl ketoximino) silane, ethyl tris (methyl ethyl ketoximino) silane, vinyl tris (methyl ethyl ketoximino) silane, allyl tris (methyl ethyl ketoximino) silane, phenyl tris (methyl ethyl ketoximino) silane, tetrakis (methyl ethyl ketoximino) silane, etc. Ketoximinosilanes, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethylto Alkoxysilanes such as ethoxysilane, tetraethoxysilane, tetrapropoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltriethoxysilane, vinyltriisopropoxysilane, vinyltrisisopropenoxysilane, diisopropenoxydimethylsilane Alkenyloxysilanes such as triisopropenoxymethylsilane, tetraallyloxysilane, and the like, but are not limited thereto. Among these, acetoxysilanes and ketoximinosilanes are preferable from the viewpoint of the curing speed of the silicone rubber layer, handling properties, and the like. Two or more of these may be contained.

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

  Examples of the curing catalyst include organic carboxylic acids, acids, alkalis, amines, metal alkoxides, metal diketenates, organic acid salts of metals such as tin, lead, zinc, iron, cobalt, calcium, and manganese. Specific examples include dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate, zinc octylate, and iron octylate. Two or more of these may be contained.

  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 rubber layer composition from the viewpoints of curability and adhesiveness of the silicone rubber layer. Further, from the viewpoint of the stability of the silicone rubber layer composition and its solution, it is preferably 15% by weight or less, more preferably 10% by weight or less in the silicone rubber layer composition.

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

  Further, for the purpose of imparting plate inspection properties to the waterless lithographic printing plate after development, it is preferable to contain a colored pigment in the silicone rubber layer. 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 general, pigments are insoluble in solvents such as water and aliphatic hydrocarbons. Therefore, by including pigments, water and organic chemicals used in the development process can be used compared to the case of containing dyes that are soluble in water and solvents. Dye extraction with solvents and various cleaning agents in the ink used in the printing process is remarkably suppressed.

  Examples of the plate inspection property of the waterless planographic printing plate after development include visual plate inspection property by visual inspection and device plate inspection property by a halftone dot area ratio measuring device. In general, since the image inspection ability is lower than the visual inspection ability, the waterless lithographic printing plate having good inspection performance often has good visual inspection ability.

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. For this reason, when the difference in the amount of reflected light between the image area and the non-image area is small, or when there is no difference in the amount of reflected light, it is difficult to measure the dot area ratio, and the device inspection performance is degraded. Many of the organic compounds that make up the heat-insulating and heat-sensitive layers of direct-drawing waterless lithographic printing plate precursors absorb blue light, so use a silicone rubber layer colored with colored pigments such as yellow and orange that absorb blue light. In this case, the difference in the amount of reflected light between the image area / non-image area is reduced, and the device inspection is deteriorated. Furthermore, the visual plate inspection property may also deteriorate. For these reasons, it is preferable to use a colored pigment that absorbs green light or red light from the viewpoints of instrument inspection and visual inspection. Furthermore, among colored pigments that absorb green light or red light, colored pigments having a density of 3 g / cm ³ or less are preferable from the viewpoint of dispersibility in the silicone rubber layer composition and its solution. Among colored pigments that absorb green light or red light, those having a density of 3 g / cm ³ or less include cobalt blue, bitumen, hydrous oxalate, ultramarine, carbon black, extender pigments (lime carbonate powder, precipitated) Printing pigments in which basic calcium carbonate, gypsum, asbestos, clay, silica powder, diatomaceous earth, talc, basic magnesium carbonate, alumina white) are dyed with dyes such as rhodamine, methyl violet, peacock blue, alkali blue, malachite green, alizarin , 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, Examples include phthalocyanine green, anthraquinone pigment, perylene red, thioindigo red, indanthrone blue, quinacridone red, quinacridone violet, dioxazine violet, and naphthol green B. Two or more of these may be contained.

  In the direct-drawing waterless planographic printing plate precursor of the present invention, the content of the colored pigment is preferably 0.1% by volume or more, more preferably 0.2% by volume or more in the silicone rubber layer. Moreover, from a viewpoint of maintaining the ink repellency of a silicone rubber layer, 20 volume% or less is preferable and 10 volume% or less is more preferable.

  In order to improve the dispersibility of the colored pigment in the silicone rubber layer, the silicone rubber layer composition preferably contains a pigment dispersant. By containing the pigment dispersant, it is possible to suppress the aggregation of the colored pigment that occurs with time in the silicone rubber layer composition or its solution when the silicone rubber layer composition is diluted with a solvent. As the pigment dispersant, a pigment dispersant that wets the pigment surface well and has good affinity with low-polar compounds such as organopolysiloxane and a solvent used for diluting the colored pigment-containing silicone liquid described later is preferable. If it is such a pigment dispersant, a well-known pigment dispersant can be used. The pigment dispersant is sometimes used as a name such as 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.

  Examples of the metal and organic compound that form the organic complex compound include the metal and organic compound that form the metal complex compound exemplified above as the crosslinking agent of the heat-sensitive layer. Among these, as the organic compound, acid compounds such as carboxylic acid, phosphoric acid, and sulfonic acid, and diketones, ketoesters, and diester compounds capable of forming a chelate ring with a metal are preferable from the viewpoint of coordination power with the metal.

  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 type: “Octope” (registered trademark) Al, “Olyp” AOO, AOS (above, manufactured by Hope Pharmaceutical Co., Ltd.), “Plenact” (registered trademark) AL-M (produced by Ajinomoto Fine Techno Co., Ltd.), and the like. Titanium-based: “Pureact” KR-TTS, KR46B, KR55, KR41B, KR38S, KR138S, KR238S, KR338X, KR9SA (above, manufactured by 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. Specific examples include “Solsperse” (registered trademark) 9000, 13240, 13650, 13940, 17000, 18000, 19000, 28000 (above, manufactured by LUBRIZOL).

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.

  In the direct-drawing waterless planographic printing plate precursor of the present invention, the average thickness of the silicone rubber layer is preferably 0.5 to 20 μm. If the average film thickness of the silicone rubber layer on the heat-sensitive layer is 0.5 μm or more, the ink repellency, scratch resistance and printing durability of the printing plate will be sufficient, and if it is 20 μm or less, it will be disadvantageous from an economic standpoint. Therefore, the developability and ink mileage are not easily lowered. Here, in the case of a direct-drawing waterless lithographic printing plate precursor containing non-photosensitive particles in the heat-sensitive layer, the average film thickness of the silicone rubber layer is the silicone rubber on the heat-sensitive layer in the portion where the non-photosensitive particles are not present Refers to the average film thickness of the layer. The average film thickness of the silicone rubber layer can be determined by TEM observation. More specifically, a sample is prepared from a direct-drawing waterless lithographic printing plate precursor by an ultrathin section method, and TEM observation is performed under the conditions of an acceleration voltage of 100 kV and a magnification of 2000 times. In the TEM observation image of the obtained vertical section, the average film thickness can be obtained by measuring the film thickness at 10 locations randomly selected from the silicone rubber layer and calculating the number average value thereof. In the case of a direct-drawing waterless lithographic printing plate precursor containing non-photosensitive particles in the heat-sensitive layer, 10 spots randomly selected from the silicone rubber layer on the heat-sensitive layer in a smooth portion without the presence of non-photosensitive particles The number average value of the film thickness is calculated.

  For the purpose of improving adhesion between the substrate and the heat-sensitive layer, preventing light halation, improving plate inspection, improving heat insulation, and improving printing durability, a heat insulating layer may be provided on the substrate. As a heat insulation layer used for this invention, the heat insulation layer described in Unexamined-Japanese-Patent No. 2004-199016, Unexamined-Japanese-Patent No. 2004-334025, Unexamined-Japanese-Patent No. 2006-276385 etc. can be mentioned, for example.

  The direct-drawing waterless lithographic printing plate precursor of the present invention has a protective film formed from the protective film-forming composition of the present invention on a silicone rubber layer. When the protective film covers the surface of the silicone rubber layer, adhesion of foreign matters to the silicone rubber layer is suppressed. For this reason, adhesion when a foreign material contacts the surface of the printing plate precursor can be prevented. Alternatively, in the cleaning of the printing plate precursor surface that can be performed before the exposure process or simultaneously with the exposure process, it is easy to remove the deposits from the printing plate precursor surface. By these actions, it becomes possible to reduce the factor of exposure inhibition caused by blocking the laser beam.

  The thickness of the protective film is preferably 0.1 μm or more and 1.0 μm or less. By setting the film thickness to 0.1 μm or more, it is possible to further suppress the adhesiveness of the surface of the direct-drawing waterless lithographic printing plate precursor and further suppress the adhesion of foreign matters. Moreover, the sensitivity fall with respect to laser exposure can be suppressed more by making a film thickness into 1.0 micrometer or less. 0.5 μm or less is more preferable. Here, the film thickness of the protective film can be measured by a known optical film thickness measurement method. Examples of the optical measurement method include an ellipsometer and reflectance spectroscopy (light interference method). In addition, the thickness of the protective film can be measured by measuring the surface level difference with a laser microscope at the boundary part from which a part of the protective film is removed. Moreover, the printing plate cross section is observed with an electron microscope, and the film thickness of the protective film can be measured from the observed image.

The protective film preferably covers the entire surface of the printing plate precursor, but an embodiment in which a part of the surface of the printing plate precursor is not covered with the protective film can be selected as long as the effects of the present invention are obtained. For the purpose of suppressing the adhesion of foreign matter, it is preferable that the portion not covered with the protective film on the surface of the printing plate precursor has a small portion having a spread where the maximum diameter of the inscribed circle is 1,000 μm or more. The number is preferably 1 or less for 1 cm ^{2 of the} surface of the printing plate precursor. Furthermore, it is preferable that the number of the inscribed circles with a maximum diameter of 100 μm or more is 100 or less, more preferably 30 or less, more preferably 10 or less with respect to 1 cm ^{2 of the} printing plate precursor surface. Further preferred. The portion where the protective film is not coated can be observed as an enlarged image of the printing plate precursor using an optical microscope.

  In the direct-drawing waterless planographic printing plate precursor of the present invention, a protective film may be further provided on the protective film for the purpose of preventing the silicone rubber layer from being damaged in the process up to exposure. This protective film is removed prior to exposure. Furthermore, you may have a slip for the same purpose.

  Next, a method for producing the direct-drawing waterless planographic printing plate precursor of the present invention will be described. The method for producing a direct-drawing waterless lithographic printing plate precursor according to the present invention comprises forming at least a heat-sensitive layer and a silicone rubber layer on a substrate and then applying the protective film-forming composition of the present invention onto the silicone rubber layer. Thereafter, the protective film is formed by drying. For example, (a) a step of applying a heat-sensitive layer composition solution on a substrate or a substrate on which a heat insulating layer is laminated, (b) a step of drying the heat-sensitive layer composition solution to form a heat-sensitive layer, (c ) A step of applying a silicone rubber layer composition on the heat-sensitive layer, or applying a silicone rubber layer composition solution and then drying to form a silicone rubber layer; (d) the protection of the present invention on the silicone rubber layer; Examples of the method include at least a step of forming a protective film by applying a film-forming composition and then drying it.

First, (a) the process of applying a heat-sensitive layer composition solution on a substrate or a substrate on which a heat insulating layer is laminated will be described. The heat-sensitive layer composition solution comprises the above-mentioned heat-sensitive layer constituents, preferably a solvent having a solubility parameter of 17.0 (MPa) ^1/2 or less, preferably a solvent having a solubility parameter of more than 17.0 (MPa) ^1/2 and Contains other components as required. The concentration of the total solid content in the heat-sensitive layer composition solution is preferably 2 to 50% by weight. By adding a solvent having a solubility parameter of 17.0 (MPa) ^1/2 or less and a solvent having a solubility parameter exceeding 17.0 (MPa) ^1/2 in the heat-sensitive layer composition solution, bubbles are formed in the heat-sensitive layer. Or a liquid bubble can be formed.

In particular, in the thermosensitive layer composition solution, the solubility parameter is 17.0 (MPa) ^1/2 or less and the solvent has a boiling point in the range of 210 to 270 ° C., and the solubility parameter is 17.0 (MPa). It is preferable to include a solvent exceeding ^1/2 , and a liquid bubble containing a liquid having a boiling point in the range of 210 to 270 ° C. can be formed in the heat-sensitive layer.

Specific examples of the solvent having a solubility parameter of 17.0 (MPa) ^1/2 or less and having a boiling point in the range of 210 to 270 ° C. include straight chain, branched or 12 to 18 carbon atoms. Cyclic hydrocarbon, normal paraffin grade M (boiling point: 219 to 247 ° C., solubility parameter: 16.2 (MPa) ^1/2 (manufactured by Nippon Oil Corporation)), normal paraffin grade H (boiling point: 244 to 262) ° C, solubility parameter: 16.2 (MPa) ^1/2 (manufactured by Nippon Oil Corporation)), “NS Clean” 230 (boiling point: 227 ° C., solubility parameter: 16.2 (MPa) ^1/2 (( Co., Ltd.) JOMO San Energy)), "Isopar" (registered trademark) M (boiling point: 223~254 ℃, solubility parameter: 14.7 ^{(MPa) 1/2} (Ekusonmobi Chemical Co., Ltd.)), "IP Solvent" 2028 (boiling point: 213~262 ℃, solubility parameter: 14.3 ^{(MPa) 1/2} (Idemitsu Kosan Co., Ltd.)), "IP clean" HX (boiling point: 222 ˜261 ° C., solubility parameter: 14.3 (MPa) ^1/2 (manufactured by Idemitsu Kosan Co., Ltd.)) and the like, “Naphthezole” (registered trademark) 220 (boiling point: 221-240 ° C., solubility) Parameters: 16.4 (MPa) ^1/2 (manufactured by Nippon Oil Corporation)) and the like, diethylene glycol butyl methyl ether (boiling point: 212 ° C., solubility parameter: 16.0 (MPa) ^{1 / 2),} diethylene glycol dibutyl ether (boiling point: 256 ° C., solubility parameter: 15.8 ^{(MPa) 1/2),} triethylene glycol di Chirueteru (boiling point: 216 ° C., solubility parameter: 16.2 ^{(MPa) 1/2),} triethylene glycol butyl methyl ether (boiling point: 261 ° C., solubility parameter: 16.2 ^{(MPa) 1/2),} tripropylene glycol Examples include alkylene glycol dialkyl ethers such as dimethyl ether (boiling point: 215 ° C., solubility parameter: 15.1 (MPa) ^1/2 ). Two or more of these may be included.

Further, as a solvent having a solubility parameter of 17.0 (MPa) ^1/2 or less and having a boiling point in a part of the range of 210 to 270 ° C., specifically, “naphthethol” 200 (boiling point: 201 ˜217 ° C., solubility parameter: 16.2 (MPa) ^1/2 (manufactured by Nippon Oil Corporation), “Dust Clean” 300 (boiling point: 201-217 ° C., solubility parameter: 16.2 (MPa) ^{1 / 2} (Matsumura Oil Co., Ltd.)), “Dust Clean” 300AF (boiling point: 201-217 ° C., solubility parameter: 16.2 (MPa) ^1/2 (Matsumura Oil Co., Ltd.)), polyethylene glycol dimethyl ether (Boiling point: 264 to 294 ° C., solubility parameter: 16.6 (MPa) ^1/2 ) and the like. Two or more of these may be included.

The ratio of the liquid having a boiling point in the range of 210 to 270 ° C. in the solvent having a solubility parameter of 17.0 (MPa) ^1/2 or less contained in the heat-sensitive layer composition solution is preferably 80% by weight or more, and 90% by weight or more. Is more preferable, 95% by weight or more is more preferable, and 100% by weight is further preferable.

The content of the solvent having a solubility parameter of 17.0 (MPa) ^1/2 or less and having a boiling point in the range of 210 to 270 ° C. is solid from the viewpoint of further improving the initial sensitivity and the sensitivity after aging. 0.1 parts by weight or more is preferable with respect to 100 parts by weight per minute, and 1 part by weight or more is more preferable. On the other hand, from the viewpoint of applicability of the heat-sensitive layer composition solution, 60 parts by weight or less is preferable with respect to 100 parts by weight of the heat-sensitive layer solid content, and 25 parts by weight or less is more preferable. Further, from the viewpoint of further improving the initial sensitivity and sensitivity after aging, the content in the heat-sensitive layer composition solution is preferably 0.1% by weight or more, more preferably 0.5% by weight or more. On the other hand, from the viewpoint of applicability of the heat-sensitive layer composition solution, it is preferably 10% by weight or less, more preferably 7% by weight or less, and more preferably 5% by weight or less in the heat-sensitive layer composition solution.

As the solvent having a solubility parameter exceeding 17.0 (MPa) ^1/2 , those capable of dissolving or dispersing the heat-sensitive layer constituents are preferable. For example, alcohols, ethers, ketones, esters, amides and the like can be mentioned. Two or more of these may be contained. Further, a solvent having a solubility parameter of 17.0 (MPa) ^1/2 or less and compatible with a liquid having a boiling point in the range of 210 to 270 ° C. is particularly preferable.

The size of the liquid bubbles is closely related to the boiling point of the solvent having a solubility parameter exceeding 17.0 (MPa) ^1/2 and the ambient temperature when the heat-sensitive layer composition solution is applied. As a solvent having a solubility parameter exceeding 17.0 (MPa) ^1/2 , when a low-boiling solvent that easily evaporates at the ambient temperature when applying the heat-sensitive layer composition solution is used, the low-boiling solvent is quickly used. In order to evaporate and dry before the adjacent liquid bubble forming components gather, small liquid bubbles are formed in the heat sensitive layer. On the other hand, when a high-boiling solvent that does not easily evaporate at the ambient temperature when applying the heat-sensitive layer composition solution is used, the high-boiling solvent evaporates slowly and dries while the adjacent liquid bubble forming components gather. Large liquid bubbles are formed in the heat-sensitive layer.

In the solvent having the solubility parameter exceeding 17.0 (MPa) ^1/2 , the solvent having a boiling point of 30 to 200 ° C. is preferably 80% by weight or more, and more preferably 95% by weight or more. Moreover, it is more preferable to contain 80 weight% or more of solvent with a boiling point of 80 degrees C or less, and it is more preferable to contain 95 weight% or more. Moreover, it is more preferable to contain 80 weight% or more of solvent with a boiling point of 70 degrees C or less, and it is more preferable to contain 95 weight% or more. By containing 80% by weight or more of a solvent having a boiling point of 30 ° C. or higher, a stable coating solution can be easily prepared at room temperature without using a special cooling device. Further, by containing 80% by weight or more of a solvent having a boiling point of 200 ° C. or less, it can be easily removed from the heat-sensitive layer by drying described later.

Further, when the boiling point of the solvent having a solubility parameter exceeding 17.0 (MPa) ^1/2 is lower than the thermal softening point of the polymer having active hydrogen, it is advantageous for the formation of liquid bubbles.

  The heat-sensitive layer composition solution may be applied directly on the substrate, or if necessary, a heat-sensitive layer composition solution may be applied after a resin layer such as a heat insulating layer is laminated on the substrate. It is preferable to degrease the coated surface of the substrate.

  Examples of coating devices include slit die coaters, direct gravure coaters, offset gravure coaters, reverse roll coaters, natural roll coaters, air knife coaters, roll blade coaters, variver roll blade coaters, two stream coaters, rod coaters, and dip coaters. , Curtain coater, spin coater and the like. A slit die coater, a gravure coater, and a roll coater are particularly preferable in terms of coating film accuracy, productivity, and cost.

The coating weight of the heat-sensitive layer composition solution is suitably in the range of 0.1 to 10 g / m ² in terms of weight after drying in terms of printing durability of the printing plate and diluting solvent being easy to evaporate and excellent productivity. Is in the range of 0.5-7 g / m ² .

  Next, the step (b) of forming the heat sensitive layer by drying the heat sensitive layer composition solution will be described. Drying of the heat-sensitive layer composition solution is performed without heating or under heating. In the case of heating, it is preferable to dry at a temperature of 30 to 190 ° C., more preferably 50 to 150 ° C. for 30 seconds to 5 minutes using a hot air dryer or an infrared dryer.

  Next, (c) a step of applying a silicone rubber layer composition on the heat sensitive layer or applying a silicone rubber layer composition solution and then drying to form a silicone rubber layer will be described. Here, the silicone rubber layer composition is a solventless liquid composed of a material forming the silicone rubber layer, and the silicone rubber layer composition solution is a dilute solution containing the silicone rubber layer composition and a solvent. .

Examples of the solvent used in the dispersion of the colored pigment and the silicone rubber layer composition solution include aliphatic saturated hydrocarbons, aliphatic unsaturated hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, ethers, and the like. It is done. The solubility parameter of these solvents is preferably 17.0 (MPa) ^1/2 or less, and more preferably 15.5 (MPa) ^1/2 or less. For example, hexane, heptane, octane, nonane, decane, undecane, dodecane, isooctane, “Isopar” C, “Isopar” E, “Isopar” G, “Isopar” H, “Isopar” K, “Isopar” L, “Isopar” "Molecular saturated hydrocarbons such as M (manufactured by Exxon Chemical Co., Ltd.), aliphatic unsaturated hydrocarbons such as hexene, heptene, octene, nonene, and decene, and alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclohexane And halogenated hydrocarbons such as trifluorotrichloroethane, ethers such as diethyl ether, diisopropyl ether, and diisobutyl ether. Two or more of these may be used. From the viewpoints of economy and safety, aliphatic and alicyclic hydrocarbons are preferred. These aliphatic and alicyclic hydrocarbons preferably have 4 to 20 carbon atoms, and more preferably 6 to 15 carbon atoms.

  Below, the specific preparation method of (i) silicone rubber layer composition and (ii) silicone rubber layer composition solution is described.

(I) Silicone rubber layer composition (solvent-free)
For example, a silicone paste is obtained by uniformly dispersing and mixing a hydroxyl or vinyl group-containing organopolysiloxane and, if necessary, a colored pigment, a pigment dispersant, and fine particles with a disperser. Examples of the disperser include three rolls, a ball mill, a bead mill, a sand mill, a disperser, a homogenizer, an attritor, and an ultrasonic disperser. In the resulting silicone paste, add a cross-linking agent, reaction catalyst, and other additives (reaction inhibitor, etc.) as necessary. Stir to homogenize the components and remove air bubbles mixed in the liquid. By removing, a silicone rubber layer composition is obtained. The defoaming may be natural defoaming or vacuum defoaming, but vacuum defoaming is more preferable.

(Ii) Silicone rubber layer composition solution (containing solvent)
For example, a silicone paste is obtained by uniformly dispersing and mixing a hydroxyl group or vinyl group-containing organopolysiloxane and, if necessary, a colored pigment, a pigment dispersant, and fine particles with the disperser described above, and diluted with a solvent while stirring this. To do. 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, reaction catalyst, and other additives (such as reaction inhibitors) as necessary to the diluted liquid after sufficient water removal, and stir it to make the components uniform. Remove foam. Defoaming may be natural defoaming or vacuum defoaming.

  Further, as another method for producing a silicone rubber layer composition solution containing a colored pigment, there is a method in which a colored pigment dispersion and a silicone liquid or a silicone dilution liquid are separately prepared in advance, and then both liquids are mixed. Can be mentioned. 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 is obtained by mixing a hydroxyl group or vinyl group-containing organopolysiloxane, a crosslinking agent, a reaction catalyst, and other additives (such as a reaction inhibitor) as necessary. Moreover, a silicone dilution liquid can be obtained by diluting the obtained silicone liquid with a solvent.

  When applying the silicone rubber layer composition or the silicone rubber layer composition solution, it is preferable from the viewpoint of adhesiveness to remove moisture adhering to the surface of the heat sensitive layer as much as possible. Specifically, a method in which the silicone rubber layer composition or the silicone rubber layer composition solution is applied in a space in which moisture is removed by filling or continuously supplying a dry gas can be mentioned. As an example of a coating device, what was illustrated as a coating device of the thermosensitive layer composition solution can be mentioned.

The coating weight of the silicone rubber heat-sensitive layer composition or the composition solution is 0.5 g / m ² or more in terms of ink repellent weight after drying, and 20 g / m ² or less for the purpose of not deteriorating economic viewpoint and ink mileage. Is suitably in the range of 0.5 to 5 g / m ² .

  When the silicone rubber layer composition solution is applied, the silicone rubber layer composition solution is then dried to form a silicone rubber layer. You may heat-process for drying and hardening. The silicone rubber layer composition and the silicone rubber layer composition solution are preferably heated immediately after application from the viewpoint of curability and heat-sensitive layer adhesion. In the case of heating, it is preferable to dry at a temperature of 30 to 190 ° C., more preferably 50 to 150 ° C. for 30 seconds to 5 minutes using a hot air dryer or an infrared dryer.

  Next, (d) the step of forming the protective film by applying the protective film-forming composition of the present invention on the silicone rubber layer and drying it will be described.

  The composition solution for forming a protective film contains the above-mentioned protective film constituents and, if necessary, other components. The concentration of the total solid content in the protective film-forming composition solution is preferably 2 to 50% by weight.

  The said protective film formation composition solution is apply | coated on a silicone rubber layer. As an example of a coating device, what was illustrated as a coating device of the thermosensitive layer composition solution can be mentioned.

The coating weight of the protective film-forming composition solution is preferably such that the film thickness after drying is 1.0 μm or less from the viewpoint of further suppressing the decrease in sensitivity to laser exposure, while foreign matter adheres to the silicone rubber layer surface. From the viewpoint of further suppressing the weight, a weight at which the film thickness after drying is 0.1 μm or more is preferable. More preferably, it is in the weight range where the film thickness after drying is 0.1 μm or more and 0.5 μm or less. The protective film preferably covers the entire surface of the printing plate precursor, but an embodiment in which a part of the surface of the printing plate precursor is not covered with the protective film can be selected as long as the effects of the present invention are obtained. For the purpose of suppressing the adhesion of foreign matter, the portion of the printing plate precursor surface that is not covered with the protective film has a broadened portion where the maximum diameter of the inscribed circle is 1,000 μm or more. It is preferable that the number is 1 or less per 1 cm ² . Furthermore, it is preferable that the number of the inscribed circles with a maximum diameter of 100 μm or more is 100 or less, more preferably 30 or less, more preferably 10 or less with respect to 1 cm ^{2 of the} printing plate precursor surface. Further preferred. As the portion not covered with the protective film on the surface of the printing plate precursor, the portion having a spread where the maximum diameter of the inscribed circle is 1,000 μm or more is less than 1 with respect to 1 cm ^{2 of the} surface of the printing plate precursor. As a result, it is possible to suppress the adhesion of foreign matters that cause exposure inhibition by adhering to the surface of the printing plate precursor and blocking the laser beam.

  The composition for forming a protective film forms a protective film by coating on the silicone rubber layer and then drying. Heat treatment may be performed for drying. In the case of heating, it is preferable to dry at a temperature of 30 to 190 ° C., more preferably 50 to 150 ° C. for 30 seconds to 5 minutes using a hot air dryer or an infrared dryer.

  On the obtained direct-drawing waterless lithographic printing plate precursor, a protective film and / or a slip sheet may be laminated and stored as necessary from the viewpoint of protecting the plate surface.

  Next, a method for producing a waterless planographic printing plate from the direct-drawing waterless planographic printing plate precursor of the present invention will be described. Here, the waterless lithographic printing plate is a printing plate having a silicone rubber layer pattern as an ink repellent layer on the surface, wherein the silicone rubber layer pattern is defined as a non-image area and a portion without a silicone rubber layer. Used as a printing method in which ink is applied only to the image area using the difference in ink adhesion between the non-image area and the image area, and then the ink is transferred to the printing medium such as paper. Printed version. A method for producing a waterless lithographic printing plate comprises a step of exposing at least the direct-drawing waterless lithographic printing plate precursor of the present invention according to an image with a laser beam (exposure step), and exposing the exposed direct-drawing waterless lithographic printing plate precursor And a step (development step) of removing the silicone rubber layer in the exposed portion by rubbing without using a liquid or in the presence of water or a solution obtained by adding a surfactant to water. If necessary, you may have the process (water-washing process) of removing a development waste further.

  First, the exposure process will be described. The direct-drawing waterless lithographic printing plate precursor of the present invention is exposed according to an image by a laser beam scanned by digital data. Examples of the laser light source used in the exposure step include those having an emission wavelength region in the range of 700 to 1500 nm. Among these, a semiconductor laser or a YAG laser having an emission wavelength region in the vicinity of the near infrared region is preferably used. Specifically, from the viewpoint of handling of the plate material in a bright room, 780 nm, 830 nm, and 1064 nm. A laser beam having a wavelength is preferably used for exposure.

  Next, the development process will be described. After exposure, the exposed original silicon rubber layer is removed by rubbing without using a liquid or in the presence of water or a solution obtained by adding a surfactant to water (hereinafter referred to as a developer). Is done. Examples of the rubbing treatment include (i) a method of rubbing the plate surface with a developing pad and / or a brush or a dry cotton pad without using a liquid, and (ii) for example, a nonwoven fabric impregnated with a developing solution, absorbent cotton, cloth, sponge. (Iii) A method in which the plate surface is pretreated with a developer and then rubbed with a rotating brush while showering tap water, etc. (iv) A method in which high-pressure water, warm water, or steam is jetted onto the plate surface, etc. Is mentioned.

  The protective film may be removed before development. Examples of the method for removing the protective film include a method in which the protective film is dissolved with a solvent, a method in which the protective film is partially swollen with the solvent, and a method in which the protective film is transferred to a film or the like via an adhesive.

  Moreover, you may perform the pretreatment which immerses a plate for a fixed time in a pretreatment liquid before image development. 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 and cost for disposal. 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. Further, a pretreatment liquid and a developer 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).

  In addition, for the purpose of improving the visibility of the image area and the measurement accuracy of the halftone dots, dyes such as crystal violet, Victoria pure blue, and Astrazone red are added to these developers to develop ink reception at the same time as the development. The layer can also be dyed. Furthermore, it can also dye | stain with the liquid which added said dye after image development.

  Part or all of the development process 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 postprocessing unit is provided in this order, a preprocessing unit, a developing unit The apparatus etc. which were provided with the post-processing part and the water washing part in this order can be used. Specific examples of such an automatic processor include TWL-650 series, TWL-860 series, TWL-1160 series (all manufactured by Toray Industries, Inc.), JP-A-4-2265, and JP-A-5- Examples thereof include automatic developing machines disclosed in Japanese Patent No. 2272, Japanese Patent Application Laid-Open No. 5-6000, and the like, and these can be used alone or in combination.

  When the development-processed waterless planographic printing plates are stacked and stored, it is preferable to sandwich a slip sheet between the plates for the purpose of protecting the plate surface.

  Hereinafter, the present invention will be described in more detail with reference to examples. Evaluation in each Example and Comparative Example was performed by the following method.

(1) TEM observation of direct-drawing waterless lithographic printing plate precursor A sample was prepared from the direct-drawing waterless lithographic printing plate precursor before laser irradiation by an ultrathin section method. Transmission electron microscope: H-1700FA type (manufactured by Hitachi High-Technologies Corporation) was used to observe the cross section of the thermosensitive layer at an acceleration voltage of 100 kV and a magnification of 2000 times. The average film thickness of the protective film, silicone rubber layer, heat-sensitive layer, heat-insulating layer, average particle diameter of the non-photosensitive particles contained in the heat-sensitive layer, the in-plane occupation ratio of the non-photosensitive particles, and the number of liquid bubbles contained in the heat-sensitive layer The average diameter was measured by the method described below.

(1-1) Average film thickness of protective film, silicone rubber layer, heat-sensitive layer, and heat-insulating layer Selected randomly in a TEM photograph of a vertical section of a direct-drawing waterless lithographic printing plate precursor obtained by an ultrathin section method The film thicknesses of the protective film, the silicone rubber layer, the heat sensitive layer, and the heat insulating layer were measured at 10 locations, and the number average value was defined as the average film thickness. When non-photosensitive particles were included in the heat-sensitive layer, the film thickness was measured for a smooth portion where non-photosensitive particles were not present, and the number average value thereof was taken as the average film thickness of the heat-sensitive layer.

(1-2) Average particle size and in-plane occupancy of non-photosensitive particles contained in heat-sensitive layer Three-dimensional information of horizontal section of direct-drawing waterless planographic printing plate precursor obtained by continuous (ultra-thin) section method From these, the average particle size and the in-plane occupation ratio of the non-photosensitive particles were calculated. The particle size (equivalent volume sphere equivalent diameter) of 50 randomly selected non-photosensitive particles was measured, and the number average value was taken as the average particle size. Further, the ratio of the non-photosensitive particles in the unit area was defined as the in-plane occupation ratio (area%) of the non-photosensitive particles.
(Example of in-plane occupancy ratio of non-photosensitive particles)
Total horizontal cross section: 100 μm ²
Number of non-photosensitive particles: 20 Average particle diameter of non-photosensitive particles: 1 μm (radius: 0.5 μm)
Non-photosensitive particle occupancy = 100 × π (0.5 <μm>) ² × 20 <piece> / 100 <μm ² > = 15.7 <area%>

(1-3) Number of liquid bubbles contained in heat-sensitive layer In a black and white continuous tone TEM observation image, the presence or absence of white circular portions (corresponding to the cross-section of liquid bubbles) observed in the gray background of the heat-sensitive layer was observed. The total number of circles having a diameter of 0.01 μm or more among circular portions observed within 5 μm ^{2 of the} heat-sensitive layer cross section (depth 0.5 μm × observation width 10 μm from the heat-sensitive layer surface (interface with the silicone rubber layer)) Was the number of liquid bubbles. For the circles on the line that divides the observation area, counting was performed when more than half of the area of the circle was within the observation area, and when it was less than half, it was not counted. In addition, when formation of the phase-separation structure was recognized in the thermosensitive layer, the phase containing much liquid bubbles (the phase containing relatively little polyurethane in Example 1) was selected, and the number of liquid bubbles was determined.

(1-4) Liquid bubble average diameter Of the observed circular spots, the diameters of 30 circular spots randomly selected from those having high whiteness and a clear outline (corresponding to a cross section passing through almost the center of the liquid foam) The number average value was defined as the liquid bubble average diameter. When 30 circular portions with high whiteness and a clear outline are not observed in one TEM observation image, a circular shape with high whiteness and a clear outline is obtained from a plurality of TEM observation images with different shooting locations. Thirty locations were selected at random, and the liquid bubble average diameter was determined.

(2) Observation of phase-separated structure of heat-sensitive layer A sample having a primer layer and a heat-sensitive layer provided on an aluminum substrate, before being laminated with a silicone rubber layer, was cut into a square with a side of 10 cm, and an optical microscope: “ECLIPSE” L200 (Ltd. ) Nikon, transmission mode, objective lens: “CFI LU Plan Apo EPI” 50 × (Nikon Corporation)) connected to a digital camera: “DXM” 1200F (Nikon Corporation) Images were taken (total magnification on monitor: 1000 times) and evaluated. It was determined that the phase separation structure was formed when each phase separation structure had a linear size of 1 μm or more in any direction. When the size of each phase separation structure was less than 1 μm or phase separation could not be confirmed, it was determined that no phase separation structure was formed.

(3) Number of uncovered portions of protective film The surface of the printing plate precursor on which the protective film was formed was observed with an optical microscope, and the uncoated portion where the protective film was not formed was inspected. For the five observation portions with an area of 1 cm ² , the number of the protective film non-covered portions having a spread where the maximum diameter of the inscribed circle is 100 μm or more is averaged, and this is the number of the non-covered portions of the protective film. did. The smaller the number of non-covered portions of the protective film, the better.

(4) Evaluation of necessary exposure amount (sensitivity) Direct drawing type waterless lithographic printing plate precursor is mounted on a laser exposure machine: “PlateRite” 8800E (manufactured by Dainippon Screen Mfg. Co., Ltd.). After the image was exposed and the protective film was removed as necessary, development was performed under the development conditions described in each Example and Comparative Example. The obtained waterless lithographic printing plate was visually observed, and the minimum exposure amount at which the silicone rubber layer of the entire exposed portion could be completely peeled was determined as the required exposure amount (sensitivity). Comparison was made with a blank (a direct-drawing waterless lithographic printing plate precursor having no plate surface protection component: Comparative Example 1 and Comparative Example 5). Compared to the blank, the smaller the required exposure increment, the better.

(5) Evaluation of the number of adhering paper dust on the plate surface (initial, after rubbing paper)
Sprinkle 10 g of “KC Flock (registered trademark)” W-100 (manufactured by Nippon Paper Chemicals Co., Ltd.) evenly over the entire surface of the direct-drawing waterless planographic printing plate precursor (surface area: 100 cm ² ) Then, a weight of 1 kg was placed thereon and allowed to stand for 24 hours. After removing the weight and blowing compressed air over the entire printing plate precursor surface, the surface of the treated printing plate precursor was observed with an optical microscope. The number of paper dusts observed at five observation portions having an area of 1 cm ² was averaged, and this was defined as the paper dust adhesion number (initial). The smaller the number of paper dust attached, the better.

Further, on the surface (surface area: 100 cm ² ) of another direct-drawing waterless lithographic printing plate precursor, a slip sheet “Kulpack” having a size of 6 cm × 10 cm (Oji Paper Co., Ltd., weighing: 73 g / m ² ) A weight of 60 g and a weight of 5 cm × 5 cm was placed on the slip sheet. Holding the edge of the slip sheet, the sheet was slowly pulled in the horizontal direction at a speed of 10 mm / second, and the surface of the printing plate precursor was rubbed with the slip sheet. For the printing plate precursor after rubbing, the number of adhering paper dust was determined in the same manner as described above, and this was used as the number of adhering paper dust (after rubbing the interleaf).

(6) Measurement of weight average molecular weight of polymer compound The weight average molecular weight of the polymer compound was determined using the GPC method under the following conditions. The polymer compound was added to tetrahydrofuran at a concentration of 0.2 w / v% and gently stirred at room temperature. It was confirmed by visual observation that the polymer compound was well dissolved, and the obtained solution was filtered through a membrane filter (pore diameter 0.45 μm, manufactured by Tosoh Corporation) as a sample.
Apparatus: Gel permeation chromatograph GPC (manufactured by Tosoh Corporation)
Detector: Differential refractive index detector RI (8020 type, sensitivity 32, manufactured by Tosoh Corporation)
Column: TSKgel G4000HXL, G3000HXL, G2000HXL (manufactured by Tosoh Corporation)
Solvent: Tetrahydrofuran Flow rate: 1.0 mL / min Injection amount: 0.200 mL
Standard sample: Monodispersed polystyrene (manufactured by Tosoh Corporation)

(7) Measurement of glass transition temperature (Tg (° C.)) of polymer compound About 5 mg of the polymer compound was weighed and packed in a sample pan to obtain a measurement sample. Based on JIS K7121-1987, it hold | maintained at -50 degreeC for 5 minutes, Then, it heated up to 100 degreeC with the temperature increase rate of 20 degreeC / min, and performed differential scanning calorimetry (DSC) measurement. The intermediate point was defined as the glass transition temperature from the observed DSC curve.

Synthesis Example 1 Synthesis of Acrylic / Silicone Graft Copolymer A Having Polydimethylsiloxane in Side Chain A silicone macromonomer X was added to a flask equipped with a stirrer, a reflux tube, a thermometer, a nitrogen introduction tube, and a liquid supply pump. -22-174DX (Shin-Etsu Chemical Co., Ltd., functional group equivalent 4,600) 30 parts by weight and methyl ethyl ketone 100 parts by weight were charged, and the temperature was raised to 70 ° C. while bubbling nitrogen. Thereafter, a mixed solution of 30 parts by weight of methyl methacrylate, 10 parts by weight of butyl acrylate, 10 parts by weight of 2-hydroxyethyl methacrylate, 20 parts by weight of styrene and 1.5 parts of dimethyl-2,2′-azobisisobutyrate is added for 2 hours. The whole amount was supplied and heated at 70 ° C. for another 5 hours. The resulting solution was dried under reduced pressure to remove methyl ethyl ketone to obtain an acrylic / silicone graft copolymer A having polydimethylsiloxane in the side chain. The resulting acrylic / silicone graft copolymer A had a weight average molecular weight of 120,000 and a glass transition temperature of 60 ° C.

Example 1
The following heat insulating layer composition solution was applied onto a 0.24 mm thick degreased aluminum substrate (Mitsubishi Aluminum Co., Ltd.) and dried at 200 ° C. for 90 seconds to provide a heat insulating layer having a thickness of 6.0 μm. In addition, the heat insulation layer composition solution was obtained by stirring and mixing the following components at room temperature.

<Insulation layer composition solution>
(A) Polymer having active hydrogen: Epoxy resin: “Epicoat” (registered trademark) 1010 (manufactured by Japan Epoxy Resin Co., Ltd.): 35 parts by weight (b) Polymer having active hydrogen: Polyurethane: “Samprene” (registered trademark) ) LQ-T1331D (manufactured by Sanyo Chemical Industries, 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 weight Part (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: “Typaque” (registered trademark) CR-50 N, N-dimethylformamide dispersion (Ishihara Sangyo Co., Ltd.) (titanium oxide 50% by weight): 60 parts by weight (f) N, N-dimethylformamide: 30 parts by weight (g) Methyl ethyl ketone: 250 parts by weight

  Subsequently, the following heat sensitive layer composition solution-1 was apply | coated on the said heat insulation layer, and it heated at 120 degreeC for 30 second, and provided the heat sensitive layer. The heat sensitive layer composition solution-1 was obtained by stirring and mixing the following components at room temperature.

<Thermosensitive layer composition solution-1>
(A) Phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR50716 (manufactured by Sumitomo Bakelite Co., Ltd., weight average molecular weight: about 3500): 100 parts by weight (b) Polyurethane solution: “Samprene” (registered trademark) LQ-X5 (manufactured by Sanyo Chemical Industries, Ltd., polyurethane obtained by polyisocyanate and polyester polyol of 50 mol% or more of aromatic polyisocyanate, thermal softening point: 185 ° C., solid content concentration: 30 wt%): 56 wt. Part (c) Infrared absorbing dye: “PROJET” 825LDI (manufactured by Avecia): 15 parts by weight (d) Titanium di-n-butoxybis (acetylacetonate) solution: “Narsem” (registered trademark) titanium (Nippon Chemical Co., Ltd.) Sangyo Co., Ltd., solid concentration: 73% by weight): 12 parts by weight (e) Tet Hydrofuran (boiling point: 66 ° C.): 620 parts by weight (f) Methyl ethyl ketone (boiling point: 79 ° C.): 51 parts by weight (g) Ethanol (boiling point: 78 ° C.): 129 parts by weight (h) Solubility parameter is 17.0 (MPa) ) is ^1/2 or less, and a liquid having a boiling point in the range of 210 to 270 ° C.: aliphatic saturated hydrocarbon: "Isopar" (trademark) M (Exxon Mobil Chemical Co., boiling point: two hundred twenty-three to two hundred and fifty-four ° C., Solubility parameter: 14.7 (MPa) ^1/2 ): 17 parts by weight

  Using the sample provided with the heat-sensitive layer, the presence or absence of a phase separation structure was observed by the above method. As a result, the phase containing a relatively large amount of polyurethane was distributed in a network in the matrix phase containing a relatively small amount of polyurethane. The phase separation structure was confirmed.

  Next, the following silicone rubber layer composition solution 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 μm.

<Silicone rubber layer composition solution>
Zirconia beads: “Isopar” (registered trademark) G (manufactured by ExxonMobil Chemical Co., Ltd.) in a sealable glass standard bottle filled with 2000 g of “YTZ” (registered trademark) balls (φ0.6 mm, manufactured by Nikkato Co., Ltd.) ): 420 g, “Plenact” (registered trademark) KR-TTS (manufactured by Ajinomoto Fine Techno Co., Ltd.): 40 g, N650 bitumen (manufactured by Dainichi Seika Co., Ltd.): 100 g, and after sealing, a small ball mill rotary mount It was set to (manufactured by ASONE Co., Ltd.) and dispersed for 336 hours at a rotational speed of 0.4 m / sec to obtain a colored pigment dispersion. The silicone rubber layer composition solution was obtained by stirring and mixing the following components at room temperature with respect to 3 parts by weight of the obtained colored pigment dispersion.
(A) Isoparaffin: “Isopar” (registered trademark) E (manufactured by ExxonMobil Chemical): 550 parts by weight (b) Vinylpolydimethylsiloxane at both ends: “DMS” V52 (manufactured by Gerest, weight average molecular weight: 155000): 81.28 parts by weight (c) SiH group-containing polysiloxane: “HMS” 991 (manufactured by Gerest): 3 parts by weight (d) vinyltris (methylethylketooxyimino) silane: 3 parts by weight (e) 3-glycidoxypropyl Trimethoxysilane: “Syra Ace” (registered trademark) S510 (manufactured by Chisso Corporation): 4 parts by weight (f) Platinum catalyst: “SRX” 212 (manufactured by Toray Dow Corning Silicone Co., Ltd.): 7 parts by weight

  Next, the following protective film-forming composition-1 was applied to the entire surface of the silicone rubber layer, and then dried to provide a protective film having a thickness of 0.3 μm to obtain a direct-drawing waterless lithographic printing plate precursor. It was. Heating was performed at 100 ° C. for 60 seconds to dry the protective film. The protective film-forming composition-1 was obtained by stirring and mixing the following components at room temperature.

<Protective film-forming composition-1>
(A) Acrylic / silicone graft copolymer A having a polydimethylsiloxane in the side chain of Synthesis Example 1: 5 parts by weight (b) n-butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.): 95 parts by weight

The obtained direct-drawing waterless lithographic printing plate precursor was subjected to TEM observation by the above method. As a result, 60 circular portions were observed in the upper part of the heat-sensitive layer cross section of 5 μm ² . The average diameter of the circular portion was 0.2 μm. When liquid bubbles were analyzed, the presence of a liquid having a boiling point in the range of 223 to 254 ° C. derived from “Isopar” M was confirmed.

  The direct exposure type waterless lithographic printing plate precursor produced in this way was evaluated for the necessary exposure increment and the number of adhering paper dust by the above-described methods. The results are shown in Table 1.

(Comparative Example 1)
A direct-drawing waterless lithographic printing plate precursor was prepared in the same manner as in Example 1 except that no protective film was formed. The results are shown in Table 1.

(Comparative Example 2)
Instead of forming a protective film, a polypropylene film “Trephan (registered trademark)” BO (manufactured by Toray Industries, Inc.) having a thickness of 8 μm was laminated using a calendar roller. The direct-drawing waterless lithographic printing plate precursor was exposed with the polypropylene film laminated. After exposure, the polypropylene film was peeled off and developed, and the required exposure was evaluated. Also, paper powder adhesion was evaluated in a state where a polypropylene film was laminated. The results are shown in Table 1.

(Example 2)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the composition for forming a protective film was changed as follows. The results are shown in Table 1.

<Protective film-forming composition-2>
(A) Acrylic / silicone graft copolymer B having polydimethylsiloxane in the side chain (manufactured by Toagosei Co., Ltd., “Symac (registered trademark)” US-270 was dried under reduced pressure, glass transition temperature 40 ° C.): 5 Part by weight (b) n-butyl methyl ether (Tokyo Chemical Industry Co., Ltd.): 95 parts by weight

(Example 3)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the composition for forming a protective film was changed as follows. The results are shown in Table 1.

<Protective film-forming composition-3>
(A) Polystyrene (manufactured by Aldrich, weight average molecular weight 192,000, glass transition temperature 100 ° C.): 5 parts by weight (b) n-butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.): 95 parts by weight

Example 4
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 3 except that the thickness of the protective film was changed to 0.7 μm. The results are shown in Table 1.

(Example 5)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the composition for forming a protective film was changed as follows. The results are shown in Table 1.

<Protective film forming composition-4>
(A) Polystyrene (manufactured by Aldrich, weight average molecular weight 192,000, glass transition temperature 100 ° C.): 5 parts by weight (b) n-butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.): 80.8 parts by weight (c ) Toluene (manufactured by Tokyo Chemical Industry Co., Ltd.): 14.2 parts by weight The weight ratio of n-butyl methyl ether to toluene was 85:15.

(Example 6)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the composition for forming a protective film was changed as follows. The results are shown in Table 1.

<Protective film-forming composition-5>
(A) Polystyrene (manufactured by Aldrich, weight average molecular weight 192,000, glass transition temperature 100 ° C.): 5 parts by weight (b) n-butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.): 66.5 parts by weight (c ) Toluene (manufactured by Tokyo Chemical Industry Co., Ltd.): 28.5 parts by weight The weight ratio of n-butyl methyl ether and toluene was 70:30.

(Example 7)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the composition for forming a protective film was changed as follows. The results are shown in Table 1.

<Protective film-forming composition-6>
(A) Polystyrene (manufactured by Aldrich, weight average molecular weight 192,000, glass transition temperature 100 ° C.): 5 parts by weight (b) tert-butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.): 66.5 parts by weight (c ) Toluene (manufactured by Tokyo Chemical Industry Co., Ltd.): 28.5 parts by weight The weight ratio of tert-butyl methyl ether to toluene was 70:30.

(Example 8)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the composition for forming a protective film was changed as follows. The results are shown in Table 1.

<Protective film-forming composition-7>
(A) Acrylic / silicone graft copolymer B having polydimethylsiloxane in the side chain (manufactured by Toagosei Co., Ltd., “Symac (registered trademark)” US-270, solid content concentration: 29% by weight, methyl ethyl ketone, methyl as solvent) (Including isobutyl ketone and toluene): 17.24 parts by weight
(B) tert-butyl methyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.): 82.76 parts by weight The weight ratio of tert-butyl methyl ether to other solvent was 87:13.

(Comparative Example 3)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the composition for forming a protective film was changed as follows. The results are shown in Table 1. Note that the application of the protective film was unstable, and the variation due to the manufacturing conditions and environment was large.

<Protective film-forming composition-8>
(A) Polystyrene (Aldrich, weight average molecular weight 192,000): 5 parts by weight
(B) Toluene (Tokyo Chemical Industry Co., Ltd.): 95 parts by weight

(Comparative Example 4)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 1 except that the composition for forming a protective film was changed as follows. The results are shown in Table 1. Note that the application of the protective film was unstable, and the variation due to the manufacturing conditions and environment was large.

<Protective film-forming composition-9>
(A) Acrylic / silicone graft copolymer B having polydimethylsiloxane in the side chain (manufactured by Toagosei Co., Ltd., “Symac (registered trademark)” US-270, solid content concentration: 29% by weight, methyl ethyl ketone, methyl as solvent) (Contains isobutyl ketone and toluene, glass transition temperature 40 ° C.): 17.24 parts by weight (b) Toluene (manufactured by Tokyo Chemical Industry Co., Ltd.): 82.76 parts by weight

  When the formed protective film was observed with an optical microscope, a minute portion in which the silicone rubber layer was partially exposed was observed.

Example 9
A direct-drawing waterless lithographic printing plate precursor was prepared in the same manner as in Example 2 except that the heat-sensitive layer composition solution was changed as follows. The results are shown in Table 2.

<Thermosensitive layer composition solution-2>
(A) Infrared absorbing dye: “PROJET” 825LDI (manufactured by Avecia): 6.6 parts by weight (b) Organic complex compound: titanium di-n-butoxide bis (acetylacetonate): “Narsem” (registered trademark) titanium (Nippon Chemical Industry Co., Ltd., concentration: 73% by weight, containing 27% by weight of n-butanol as solvent): 7.3 parts by weight (c) phenol formaldehyde novolak resin: “Sumilite Resin” (registered trademark) PR50731 (Manufactured by Sumitomo Bakelite Co., Ltd.): 49.5 parts by weight (d) Polyurethane: “Nipporan” (registered trademark) 5196 (manufactured by Nippon Polyurethane Co., Ltd., concentration: 30% by weight, methyl ethyl ketone 35% by weight, cyclohexanone 35 (Including weight%): 13.2 parts by weight (e) Non-photosensitive crosslinked acrylic resin particle dispersion: “Rio FIA "(registered trademark) RSP3021 (manufactured by Toyo Ink Manufacturing Co., Ltd., average particle size: 0.6 μm, CV value: 18.9%, specific gravity: 1.20, concentration: 20% by weight, methyl ethyl ketone as a dispersion medium: 80 15.0 parts by weight (f) Tetrahydrofuran: 1401.8 parts by weight (g) Solubility parameter is 17.0 (MPa) ^1/2 or less and boiling point in the range of 210-270 ° C. Liquid having: An aliphatic saturated hydrocarbon: “Isopar” (registered trademark) M (manufactured by ExxonMobil Chemical Co., boiling point: 223-254 ° C., solubility parameter: 14.7 (MPa) ^1/2 ): 6.6 weight Part

The solid content concentration of the heat-sensitive layer composition solution is 4.6% by weight, the solubility parameter is 17.0 (MPa) ^1/2 or less, and the content of the liquid having a boiling point in the range of 210 to 270 ° C. is 0.44% by weight.

The obtained direct-drawing waterless lithographic printing plate precursor was subjected to TEM observation by the above-described method. The average particle diameter of the non-photosensitive particles observed in the cross section of the heat-sensitive layer was 0.6 μm. The average film thickness of the heat-sensitive layer where no particles were present was 0.5 μm. The in-plane occupation ratio of the non-photosensitive particles was 5.0 area%. In addition, 50 circular spots were observed in the upper part 5 μm ^{2 of the} cross section of the heat sensitive layer where no non-photosensitive particles were present. The average diameter of the liquid bubbles was 0.15 μm. When liquid bubbles were analyzed, the presence of a liquid having a boiling point in the range of 223 to 254 ° C. derived from “Isopar” M was confirmed.

(Comparative Example 5)
A direct-drawing waterless lithographic printing plate precursor was produced in the same manner as in Example 9 except that no protective film was formed. The results are shown in Table 2.

(Example 10)
A direct-drawing waterless lithographic printing plate precursor was prepared in the same manner as in Example 3 except that the heat-sensitive layer composition solution was changed to heat-sensitive layer composition solution-2. The results are shown in Table 2.

  According to the present invention, a composition for forming a protective film suitable for silicone rubber can be obtained. Moreover, according to the composition for forming a protective film of the present invention, it is possible to obtain a method for producing a direct-drawing waterless lithographic printing plate precursor having a protective film effective for preventing foreign matter adhesion of the silicone rubber layer.

Claims (5)

A protective film-forming composition comprising a polymer compound and a compound represented by the following general formula (I):

Here, R represents a saturated hydrocarbon group having 3 to 4 carbon atoms. The composition for forming a protective film according to claim 1, wherein the polymer compound is a polymer having a glass transition temperature of 30 ° C. or higher. A method for producing a direct-drawing waterless lithographic printing plate precursor having at least a heat-sensitive layer, a silicone rubber layer and a protective film on a substrate in this order, wherein at least the heat-sensitive layer and the silicone rubber layer are formed on the substrate. A method for producing a direct-drawing waterless lithographic printing plate precursor, comprising applying the composition for forming a protective film according to 1 or 2 on the silicone rubber layer and then drying to form a protective film. The method for producing a direct-drawing waterless lithographic printing plate precursor according to claim 3, wherein the dry film thickness of the protective film is 0.1 µm or more and 1.0 µm. The method for producing a direct-drawing waterless lithographic printing plate precursor according to claim 3 or 4, wherein bubbles or liquid bubbles are formed in the heat-sensitive layer.