JP2009020449A - Printing plate original and method for manufacturing printing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printing plate original having a barrier layer and a mask layer (mask forming layer) favorably adhered, and to provide a printing plate formed by using the original. <P>SOLUTION: The printing plate original includes a photosensitive layer, a barrier layer formed on the photosensitive layer, and a mask forming layer formed on the barrier layer and removable by irradiation with an IR laser beam, wherein in the binders included in the barrier layer and in the mask forming layer, not less than 50 mass% of each binder is the same kind of binder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a printing plate precursor used for letterpress printing, and a printing plate manufacturing method using the printing plate precursor.

  In recent years, with the development of electronic devices, it has become possible to collectively manage manuscripts and print data from input, editing, proofreading to plate making in the printing field, and a direct plate making method that forms a printing plate directly from digital data. Is attracting attention.

  This direct plate making method is also called a CTP (computer to plate) method, and can be directly made from digital data as compared with a conventional plate making method using a negative film. Therefore, when image correction occurs, it is not necessary to create a new negative film, and it can be dealt with by simply correcting the digitized image data on a computer. Therefore, there is an advantage that time can be saved and labor can be reduced.

  Various methods have been proposed as direct plate making methods, but a conventional method is to provide a mask layer on a printing plate having a photosensitive layer, form an image on the mask layer, and then make a plate based on the image. It is the easiest to use as an extension of the lithography method and attracts attention.

  In this conventional printing plate manufacturing method, a method of melting and removing a mask layer with a laser beam is known as the most general method. In this method, a laser beam is applied to a photosensitive layer when the mask layer is melted and removed. In some cases, the polymerization of the photosensitive layer is inhibited by oxygen in the atmosphere due to an adverse effect and incomplete protection of the photosensitive resin after removal by melting. When the polymerization reaction on the surface of the photosensitive layer that becomes the printing plate is hindered by oxygen in the atmosphere, the upper edge of the printing plate material after development is rounded and the dot gain by printing increases, so the printing plate material As a result.

In order to improve such drawbacks, Patent Documents 1 to 3 propose a method of providing a barrier layer on the surface of the photosensitive layer for shielding the photosensitive layer from oxygen in the atmosphere.
JP 7-506201 A (July 6, 1995) US Patent Publication No. 2005-0227182 (October 13, 2005) Patent Publication 2001-356491 (December 26, 2001)

  However, the barrier layer described above may not have sufficient adhesion between the barrier layer and the mask layer. If the barrier layer and the mask layer are not sufficiently adhered, for example, when the mask layer is selectively removed to form the mask, even the mask layer desired to remain on the barrier layer may be removed. is there. This contributes to forming a printing plate having an erroneous pattern. For this reason, in a printing plate precursor for forming a printing plate having a convex pattern, an improvement in the adhesion between the barrier layer and the mask layer is required.

  The present invention has been made to solve the above-described problems, and provides a printing plate precursor having a barrier layer and a mask layer in good contact with each other and a printing plate precursor formed using the same.

  The printing plate precursor according to the present invention includes a photosensitive layer, a barrier layer provided on the photosensitive layer, a mask forming layer provided on the barrier layer and removable by irradiation with an infrared laser. And 50% by mass or more of the binders contained in the barrier layer and the mask forming layer are the same kind of binders.

  The printing plate precursor according to the present invention includes a photosensitive layer formed on a first support, a first laminate having a barrier layer provided on the photosensitive layer, and a second support. And a second laminate having a mask forming layer formed on the body and removable by irradiating with an infrared laser, and a binder contained in the barrier layer and the mask forming layer Of these, 50% by mass or more of each is a binder of the same type.

  According to the printing plate precursor according to the present invention, the barrier layer and the mask forming layer each contain the same kind of binder in the binder contained therein, and the content of the same kind of binder is contained in the barrier layer and the mask forming layer. 50% by weight of the binder to be bonded, so that the barrier layer and the mask layer (or the mask forming layer, where the mask layer is a layer obtained by selectively removing a part of the mask forming layer) Can be satisfactorily adhered. Therefore, when a part of the mask formation layer is selectively removed to form the mask layer, formation of an erroneous pattern can be suppressed. As a result, a printing plate having a highly accurate pattern can be produced by using the printing plate precursor according to the present invention.

  Hereinafter, embodiments of the present invention will be described. In the following description, when the numerical value range is indicated, the expression “to” indicates “above or below” unless otherwise specified.

[Original Plate for Printing Plate According to First Embodiment]
The printing plate precursor according to this embodiment includes a photosensitive layer, a barrier layer provided on the photosensitive layer, and a mask forming layer provided on the barrier layer and removable by irradiation with an infrared laser. And having.

(Photosensitive layer)
First, the photosensitive layer of the printing plate precursor according to this embodiment will be described. The photosensitive layer according to this embodiment contains a binder, at least one monomer, and a polymerization initiator. Then, it is washed away by the developer.

  Examples of the binder include polydiolefins such as styrene / butadiene, styrene / isoprene resin, polybutadiene, and polyisoprene, random copolymers of vinyl aromatic compounds / diolefins, block copolymers, and diolefin / acrylonitrile copolymers. Polymer, ethylene / propylene copolymer, ethylene / propylene / diolefin copolymer, ethylene / acrylic acid copolymer, diolefin / acrylic acid copolymer, diolefin / acrylic acid ester / acrylic acid copolymer, Ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, polyamide, polyvinyl alcohol, graft copolymer of polyvinyl alcohol and polyethylene glycol, amphoteric interpolymer, alkyl cellulose, hydroxyalkyl Celluloses such as cellulose and nitrocellulose, copolymers of ethylene and vinyl acetate, cellulose acetate butyrate, polybutyral, cyclic rubber, copolymers of styrene and acrylic acid, polyvinyl pyrrolidone, polyvinyl pyrrolidone and vinyl acetate A copolymer etc. are mentioned.

  Further, the monomer to be contained in the photosensitive layer needs to be compatible with the binder to be used together in order to form a cloudless transparent photosensitive layer. Examples of such monomers include, for example, ethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, trimethylol. Propane triacrylate, trimethylolpropane tri (acryloyloxypropyl) ether, trimethylol ethane triacrylate, hexanediol diacrylate, 1,4-cyclohexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol diacrylate, pentaerythritol tri Acrylate, pentaerythritol tetraacrylate, dipentaerythritol dia Acrylate esters such as relate, dipentaerythritol hexaacrylate, sorbitol triacrylate, sorbitol tetraacrylate, sorbitol pentaacrylate, sorbitol hexaacrylate, tri (acryloyloxyethyl) isocyanurate, polyester acrylate oligomers and the corresponding methacrylate esters, ethylene Like glycol diitaconate, propylene glycol diitaconate, 1,3-butanediol diitaconate, 1,4-butanediol diitaconate, tetramethylene glycol diitaconate, pentaerythritol diitaconate, sorbitol tetrataconate Itaconic acid ester, ethylene glycol dicrotonate, tetramethylene glycol dichloro Crotonic acid esters such as acrylate, pentaerythritol dicrotonate, sorbitol tetradicrotonate, ethylene glycol diisocrotonate, pentaerythritol diisocrotonate, sorbitol tetraisocrotonate, ethylene glycol dimaleate, triethylene glycol dimaleate , Maleic esters such as pentaerythritol dimaleate, sorbitol tetramaleate, methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylamide, diethylenetriamine tris Examples include unsaturated carboxylic acid amides such as acrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

  The monomer to be contained in the photosensitive layer is preferably a ratio of 1/20 to 5/1 in terms of mass ratio (monomer / binder) with respect to the binder, more preferably a ratio of 1/10 to 1/1. preferable. When the content of the binder is less than the above range, the film properties of the photosensitive layer may be deteriorated. When the content exceeds the above range, the adhesion with the barrier layer is lowered, and air is laminated when laminated. May cause troubles such as mixing or peeling from the surroundings.

  Next, the polymerization initiator contained in the photosensitive layer will be described. The polymerization initiator is sensitive to actinic rays in the non-infrared region. The polymerization initiator is preferably non-photosensitive to infrared rays at the same time. Examples of such polymerization initiators include aromatic ketones such as benzophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylol benzoin methyl ether, α-methoxybenzoin methyl ether, 2, 2 And benzoin ethers such as -diethoxyphenylacetophenone. These may be used alone or in combination of two or more. In addition, substituted and unsubstituted polynuclear quinones can also be used.

  The content of the polymerization initiator is preferably 0.5 to 50% by mass and more preferably 3 to 35% by mass with respect to the total mass of the photosensitive layer.

  The photosensitive layer in this embodiment may contain a solvent, a polymerization inhibitor, a surfactant, and the like as necessary. Solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether acetate, propylene glycol Monoethyl ether acetate, 2-methoxybutyl acetate, 3-methoxybutyl acetate, 4-methoxybutyl acetate, 2-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, 3-ethyl-3-methoxy Butyl acetate, 2-ethoxybutyl acetate DOO, 4-ethoxy butyl acetate, 4-propoxybutyl acetate, and 2-methoxy-pentyl acetate. In addition, the photosensitive layer is composed of a polymerization inhibitor such as hydroquinone or hydroquinone monoethyl ether, a silicone or fluorine antifoaming agent, an anionic, cationic or nonionic surfactant, or a matting agent such as silica. Additives commonly used in photosensitive compositions such as sensitizers, plasticizers, and colorants may also be included.

  The method for forming the photosensitive layer on the support is not particularly limited as long as it can be formed. Among the methods conventionally used for laminating the photosensitive layer on the support in producing a printing plate precursor. You can choose arbitrarily. As such a method, for example, each component of the photosensitive layer is mixed at a predetermined ratio, dissolved in an appropriate solvent such as chloroform, tetrachloroethylene, methyl ethyl ketone, toluene, etc., and cast into a mold to obtain a solvent. The components can be formed as they are, and the components can be formed as they are, without using a solvent, kneading each component with a kneader or roll mill, and forming into a layer with a predetermined thickness by an extruder, injection molding machine, press, etc. Can do. At this time, the thickness of the photosensitive layer is usually 0.1 to 3.0 mm, preferably 0.5 to 2.0 mm.

  In the present embodiment, the photosensitive layer is provided on the surface of the support. As such a support, a material that is generally used as a support for a relief printing plate and satisfies the mechanical strength and physical properties suitable for each printing condition can be used. The support can be formed by arbitrarily selecting from, for example, a metal sheet, a plastic film, paper, and a composite thereof. Specifically, polymeric films such as those formed by addition polymerization polymers and linear condensation polymers, transparent foams and fabrics, non-woven fabrics such as glass fiber fabrics and metals such as steel and aluminum are included. The support is preferably transparent to non-infrared rays. Examples of such a support include polyethylene or polyester film, and polyethylene terephthalate film is particularly preferable. The support is usually formed into a film or sheet having a thickness of 50 to 300 μm, preferably 75 to 200 μm.

  This support may have a thin adhesion promoting layer between the photosensitive layer and the photosensitive layer, if necessary. As the adhesion promoting layer, for example, a layer made of a mixture of acrylic resin and polyisocyanate is used.

(Barrier layer)
Next, the barrier layer laminated on the photosensitive layer will be described. The barrier layer serves to protect the photosensitive layer and prevent movement of components between the photosensitive layer and the mask forming layer when a mask forming layer described later is removed by infrared laser irradiation.

  In this embodiment, the barrier layer is substantially transparent to non-infrared rays, and has a solubility, swelling property, dispersibility, or floatability in a developing solution when developing the photosensitive layer, and the photosensitive layer is in the atmosphere. This layer can prevent exposure to oxygen.

  The barrier layer includes at least one binder. The binder occupying 50% by mass or more of the total mass of the binder contained in the barrier layer (hereinafter referred to as “main binder”) is contained by 50% by mass or more of the binder contained in the mask forming layer described later. It is the same kind of binder as the binder. By using the same kind of binder for the barrier layer and the mask forming layer, the adhesion between the two can be improved.

  In the present embodiment, “binder” means a polymer (polymer), and “same kind of binder” means the same kind of monomer in the case of a polymer obtained by polymerization of only one kind of monomer. A polymer produced by polymerization of a body. In the case of a polymer obtained by polymerization of two or more types of monomers, a polymer produced by polymerization combining the same type of monomers is shown. In addition, when the binder is not obtained by polymerization, the molecular level as a basic unit (repeating unit) is regarded as a monomer, and whether or not it is the same kind of binder is the same as that of the polymer produced by the above-described polymerization. It is. In addition, the same type of monomers means vinyl compounds, diene compounds, acetylene compounds, nitrile compounds, cyclic compounds, polybasic acids, polyhydric alcohols, polyamines, isocyanates, aldehydes, phenols, etc. In the general classification of the monomers used, it shall represent the same monomer.

  As the main binder, it is preferable to use a thermoplastic resin, and among these, an amide resin is more preferable. By using a thermoplastic resin as the main binder, it can be satisfactorily adhered to a mask forming layer described later. Among these, it is preferable to use an amide resin. As this amide resin, for example, Macromelt (product name) manufactured by Henkel, which is a polyamide synthesized from C36 or higher dimer acid and diamine, is preferable.

The oxygen permeability coefficient of the barrier layer is preferably 4 × 10 ⁻¹⁹ to 4 × 10 ⁻¹³ l · m / m ² · s · Pa. Within this range, it is possible to suppress an increase in dot gain by rounding the upper edge of the relief due to polymerization inhibition by oxygen in the atmosphere. For this reason, it is possible to suppress deterioration in image quality.

Further, the oxygen permeability coefficient of the barrier layer is more preferably 1 × 10 ^{−18 to} 9 × 10 ⁻¹⁴ l · m / m ² · s · Pa. If it is within this range, the edge portion at the upper part of the relief after development is about 90 °, and the dot gain by printing can be minimized.

  As described above, by using this barrier layer, it is possible to provide a printing plate precursor capable of obtaining a relief shape more suitable for printing.

  The barrier layer can further contain a plasticizer and a surfactant in order to adjust the coating properties as desired. That is, the generation of wrinkles that occur when the multilayer photosensitive material is bent or bent can be suppressed by including a plasticizer. If wrinkles occur, scratches may remain on the flexographic plate and cause a reduction in image quality, but such a problem can be avoided.

  Examples of the plasticizer contained in the barrier layer include triphenyl phosphite, dimethyl phthalate, diethyl phthalate, dicyclohexyl phthalate, ethylene glycol dibenzoate, glyceryl carbonate, polyethylene glycol, tributyl citrate, urethane oligomer, and the like. Examples of the activator include a fluorine-based surfactant.

  This barrier layer needs to be sufficiently thick in order to adjust the amount of oxygen permeation, but at the same time, it needs to be sufficiently thin in order to minimize the photosensitive inhibition effect on the photosensitive layer. For this reason, the thickness of the barrier layer having the oxygen permeability coefficient is generally selected in the range of 0.05 to 20 μm, preferably 0.1 to 10 μm.

  The solvent used for forming the barrier layer is not particularly limited as long as it does not affect or dissolve the adjacent photosensitive layer or mask forming layer. Examples of such solvents include ethers such as dioxane, diethyl ether, dibutyl ether, isopropyl ether, and tetrahydrofuran, ketones such as acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, and cyclohexanone, and ethyl acetate. , Esters such as n-propyl acetate and n-butyl acetate, aromatic hydrocarbons such as benzene, toluene and xylene, and amides such as dimethylformamide. These may be used singly or in combination of two or more. In addition, a mixed solvent of water and alcohol may be used. Examples of such alcohol include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, cyclohexyl alcohol, and 3-methyl-3-methoxybutanol.

  The barrier layer is a barrier layer forming composition prepared by dispersing or dissolving the above-described components in a solvent. The barrier layer forming composition is a wheeler, roll coater, reverse coater, electrostatic coating machine, spin coater, It is formed by coating or lamination on the photosensitive layer or mask forming layer using an apparatus such as a bar coater.

(Mask formation layer)
Next, the mask forming layer will be described. The mask formation layer concerning this embodiment is a layer which contains at least 1 sort (s) of binder, an infrared absorber, and a non-infrared shielding substance, and is excisable with an infrared laser.

  As a binder used for the mask forming layer, it is soluble in an organic solvent, a solution containing this is applied onto a flat surface, and after drying, forms a film, and when irradiated with an infrared laser, It must be melted and removed by the heat generated by the infrared absorber.

  In the present embodiment, a binder occupying 50% by mass or more of the total mass of binder contained in the mask forming layer (hereinafter referred to as “main binder”) is the same kind of binder as the main binder of the barrier layer. By using the same main binder for the barrier layer and the mask forming layer, the adhesion between the two can be improved. The content of the main binder is preferably 50 to 100% by mass and more preferably 75% by mass or more with respect to the total mass of the binder.

  In addition to the main binder, the mask forming layer may contain a binder that meets the required characteristics (physical properties, etc.) and is compatible with the main binder. What is generally called a plasticizer may also contain monomers such as phthalates.

  The mask forming layer contains an infrared absorber. This infrared absorbent absorbs the infrared laser when it is irradiated and generates heat, and serves to melt and remove the binder.

  The infrared absorber is not particularly limited as long as it absorbs an infrared laser. For example, black pigments such as carbon black, aniline black, cyanine black, phthalocyanine, naphthalocyanine-based green pigments, graphite, Iron powder, diamine-based metal complex, dithiol-based metal complex, phenolthiol-based metal complex, mercaptophenol-based metal complex, crystal water-containing inorganic compound, copper sulfate, chromium sulfide, silicate compound, chromium oxide, titanium oxide, vanadium oxide Metal oxides such as manganese oxide, iron oxide, cobalt oxide, and tungsten oxide, hydroxides and sulfates of these metals, and metal powders of bismuth, iron, magnesium, and aluminum are used.

  Among these, carbon black is preferable from the viewpoints of photothermal conversion, economy, and handleability. Carbon black can be used in a wide range of particle diameters of 10 to 100 nm. The smaller the particle diameter, the higher the sensitivity to infrared rays.

  In addition to the above substances, dyes that absorb infrared rays or near infrared rays can also be used as infrared absorbers.

  As these dyes, any dye can be used as long as it has a maximum absorption wavelength in the range of 700 to 20,000 nm. Preferred dyes include cyanine, phthalocyanine, phthalocyanine metal complex, and naphthalocyanine. , Naphthalocyanine metal complex, dithiol metal complex, naphthoquinone, anthraquinone, indophenol, indoaniline, pyrylium, thiopyrylium, squarylium, croconium, diphenylmethane, triphenylmethane, triphenylmethanephthal , Triallylmethane, phenothiazine, phenoxazine, fluoran, thiofluorane, xanthene, indolylphthalide, spiropyran, azaphthalide, chromenopyrazole, leucooramine Rhodamine lactam, quinazoline, diazaxanthene, bislactone, fluorenone, monoazo, ketone imine, diazo, polymethine, oxazine, nigrosine, bisazo, bisazostilbene, bisazooxadiazole Bisazofluorenone, bisazohydroxyperinone, azochrome complex, trisazotriphenylamine, thioindigo, perylene, nitroso, 1: 2 type metal complex, intermolecular CT, quinoline, Quinophthalone-based, fulgide-based acid dyes, basic dyes, dyes, oil-soluble dyes, triphenylmethane-based leuco dyes, cationic dyes, azo-based disperse dyes, benzothiopyran-based spiropyran, 3,9-dibromoanthanthrone, indanthrone , Phenolphthalein, sulfo Tarein, ethyl violet, methyl orange, fluorescein, methyl viologen, methylene blue, and the like gym loss betaine.

  Among these, cyanine dyes, azurenium dyes, squarylium dyes, croconium dyes, azo disperse dyes, bisazostilbene dyes, naphthoquinone dyes, anthraquinones having a maximum absorption wavelength in the range of 750 to 2,000 nm Suitable are dyes based on dyes, perylene dyes, phthalocyanine dyes, naphthalocyanine metal complex dyes, polymethine dyes, dithiol nickel complex dyes, indoaniline metal complex dyes, intermolecular CT dyes, benzothiopyran spiropyran, and nigrosine dyes. is there.

  These infrared absorbers alone have an effect of improving sensitivity, but the sensitivity can be further improved by using two or more kinds in combination. In addition, by using two or more infrared absorbers having different absorption wavelengths, it is possible to cope with two or more lasers having different transmission wavelengths.

  Although there is no restriction | limiting in particular as long as there is an effect regarding infrared absorption, content of this infrared absorber is based on 100 mass parts of binders, 0.001-10 mass parts is preferable, More preferably, 0.05-5 masses Part. When the content of the infrared absorber is less than 0.001 part by mass, the effect of improving the sensitivity to the laser is not observed, and when it is more than 10 parts by mass, the flexibility of the film may be lowered.

  The non-infrared blocking substance is not particularly limited as long as it reflects or absorbs visible light and ultraviolet light, and includes, for example, an ultraviolet absorbent, a visible light absorbent, a dark inorganic pigment, and a combination thereof. . Preferred examples of the non-infrared shielding material include carbon black and graphite.

  In particular, carbon black and graphite can function both as a non-infrared blocking substance and as an infrared absorber. Similar functions can be seen in metals and alloys, but carbon black and graphite are particularly preferably used from the viewpoint of economy and handling.

  These non-infrared shielding substances are preferably added so that the mask forming layer has a predetermined optical density, for example, an optical density of 2.0 or more.

  The content of the non-infrared shielding material may be an amount effective for non-infrared shielding, and is 5 to 40 parts by mass, preferably 15 to 25 parts by mass with respect to 100 parts by mass of the binder. When the content of the non-infrared shielding substance is less than 5 parts by mass, the non-infrared shielding effect cannot be obtained, and when it is more than 40 parts by mass, the flexibility of the coating is lowered.

  When the same substance is used as the infrared absorbing agent and the non-infrared blocking substance, 10 to 30 parts by mass is preferable with respect to 100 parts by mass of the binder.

  A leveling agent, a surfactant, a dispersant, a plasticizer, an adhesion improver, a coating aid and the like can be added to the mask forming layer as desired. The plasticizer is added to suppress the generation of wrinkles when the multilayer photosensitive material of the present invention is bent or bent. Examples of this plasticizer include triphenyl phosphite, dimethyl phthalate, diethyl phthalate, dicyclohexyl phthalate, ethylene glycol dibenzoate, glyceryl carbonate, polyethylene glycol, tributyl citrate and urethane oligomers. Further, as the surfactant, a fluorine-based surfactant is preferable.

  The mask-forming layer must be thin enough to be substantially removed quickly when exposed to an infrared laser, and is sufficient against non-infrared to effectively block non-infrared after mask formation. Must be opaque. The thickness of the mask forming layer is generally selected in the range of 0.05 to 20 μm, preferably 0.1 to 10 μm.

  The mask formation layer in this invention can be formed by apply | coating the solution containing a binder, an infrared absorber, and a non-infrared shielding substance according to a conventional method. As a preferred method for forming the mask forming layer, a binder is dissolved using a suitable solvent, and after the infrared absorbent and the non-infrared shielding material are dispersed therein, the coating is optionally performed on a cover sheet, A method of forming the barrier layer by the above-described method and then laminating or pressing the cover sheet on the photosensitive layer is effective. This method is particularly effective when carbon black or graphite is used as an infrared absorber and a non-infrared shielding material.

(Cover sheet)
In the printing plate precursor according to the present embodiment, a cover sheet can be provided on the mask forming layer as necessary, as in the case of an ordinary photosensitive material for flexographic printing plate production. The cover sheet is not particularly limited, and can be arbitrarily selected from known metals, plastic films, paper, and composites thereof that satisfy the performance required for protecting the printing plate precursor. . These include polymeric films such as those formed by addition polymerization polymers and linear condensation polymers, transparent foams and fabrics, nonwovens and metals such as steel and aluminum. Preferably, a polyethylene film, a polyester film, a polypropylene film, or a laminate of these films is used. The cover sheet is usually used as a film having a thickness of 20 to 200 μm. These exist for the purpose of protecting the mask forming layer, and are removed before drawing with an infrared laser. This cover sheet may also be covered with a release layer between the mask forming layer as required.

[Original Plate for Printing Plate According to Second Embodiment]
Next, the printing plate precursor according to the second embodiment will be described. Unlike the first embodiment, the printing plate precursor according to the second embodiment has a barrier layer and a mask forming layer formed on different supports.

  A printing plate precursor according to a second embodiment includes a first laminate having a photosensitive layer formed on a first support, a barrier layer provided on the photosensitive layer, and a second laminate. And a second laminate having a mask forming layer that can be removed by irradiation with an infrared laser formed on a support.

  The first support and the second support are the same as the support described in the first embodiment. The same applies to the photosensitive layer. Further, in the barrier layer and the mask forming layer, binders (referred to as “main binders”) occupying 50% by mass or more of the binders contained therein are the same kind of binders.

  The printing plate precursor according to this embodiment includes an exposed surface of the barrier layer (a surface of the barrier layer opposite to the surface in contact with the photosensitive layer) and an upper surface of the mask forming layer (the surface of the mask forming layer). The surface of the second support is opposite to the surface that is in contact with the second support) and bonded together to obtain a printing plate precursor in which a mask forming layer is disposed above the photosensitive layer. . Further, in the printing plate precursor according to the second embodiment, the mask forming layer can be patterned and a mask layer on which a pattern is formed in advance can be bonded (see “Method for producing printing plate” described later). reference).

[Method for producing printing plate]
Next, a method for forming a printing plate using the printing plate precursor described above will be described. The printing plate manufacturing method according to the present embodiment includes a mask layer forming step of selectively removing a mask forming layer with an infrared laser and forming a mask layer; and a photosensitive layer is entirely exposed to non-infrared via the mask layer. A pattern forming step of exposing and forming a latent image based on the mask image, and a developing step of forming a printing plate material image by processing the printing plate precursor on which the latent image is formed with one or more types of developer And including.

(Mask layer forming process)
First, the mask forming layer of the printing plate precursor is selectively removed to form a mask layer. In the present invention, an infrared laser having a wavelength of 750 to 2,000 nm can be used as the infrared laser used for selective removal of the mask forming layer. In other words, argon ions, krypton ions, helium-neon, helium-cadmium, ruby, glass, titanium, sapphire, pigment, nitrogen, metal vapor, semiconductor, YAG, etc., suitable for the necessary conditions should be used. it can. Among these, as this type of infrared laser, a semiconductor laser of 750 to 880 nm and a Nd-YAG laser of 1,060 nm are preferably used. These infrared laser generation units are controlled by a computer together with the drive system unit, and digitized image information is applied to the photosensitive material for flexographic printing plates by selectively exposing the mask forming layer on the photosensitive layer. can do.

(Pattern formation process)
Next, the entire surface of the photosensitive layer is exposed with non-infrared rays through the mask layer to form a latent image based on the mask image. As the non-infrared ray irradiated to the photosensitive layer, an electromagnetic wave having a shorter wavelength than the infrared ray, preferably an electromagnetic wave having a wavelength of 150 to 600 nm, more preferably an electromagnetic wave having a wavelength of 300 to 400 nm is preferable. Examples of the non-infrared light source include a high-pressure mercury lamp, an ultraviolet fluorescent lamp, a carbon arc lamp, and a xenon lamp. In order to make the relief image after exposure more stable, the entire surface may be exposed from the support side with respect to washing out the uncured portion during development.

(Development process)
Next, it is processed with one or more types of developers to form a printing plate material image. Thereby, the latent image can be clarified. The developer used for this development may be any of organic solution, water, aqueous or semi-aqueous solution as long as it has the property of dissolving the photosensitive layer. The choice of developer depends on the chemical nature of the resin to be removed. Suitable organic solvent developers include aromatic or aliphatic hydrocarbons and aliphatic or aromatic halohydrocarbon solvents or mixtures of these solvents with suitable alcohols. The semi-aqueous developer usually contains water and an organic solvent miscible with water and an alkaline material. The aqueous developer usually contains water and an alkaline material. For example, esters such as heptyl acetate and 3-methoxybutyl acetate, petroleum fractions, hydrocarbons such as toluene and decalin, chlorinated solvents such as tetrachloroethylene, amines such as monoethanolamine, diethanolamine and triethanolamine, water An aqueous solution of sodium oxide, potassium hydroxide, sodium carbonate, ammonia or the like is used. It is also possible to use a mixture of these solvents with alcohols such as propyl alcohol, butyl alcohol, and pentyl alcohol. Washing out is performed by any method including immersion, spraying from a nozzle, and brushing with a brush. Is called.

(Other manufacturing methods)
In the case of forming a printing plate using a printing plate precursor having a mode in which the mask forming layer and the photosensitive layer are formed on different supports, respectively, as described above, the mask forming layer and the photosensitive layer are used. There is no limitation to the method of forming a pattern after bonding together. For example, before the mask forming layer and the photosensitive layer are bonded, the mask layer having a pattern is formed by irradiating the mask forming layer with an infrared laser by the same method as the mask layer forming step. Form. Thereafter, the mask layer is opposed to the photosensitive layer by bonding to the first laminate. Specifically, the mask layer and the barrier layer come into contact with each other. Then, the printing plate concerning this embodiment can be formed through a pattern formation process and a development process.

  Unless otherwise specified, the term printing plate precursor according to this embodiment includes any form of plate or structure suitable for letterpress printing, and includes flat sheet shapes and seamless continuous shapes, It is not limited to these.

  In the printing plate precursor according to this embodiment, the main binder contained in the barrier layer and the mask forming layer is the same kind of binder. Therefore, the adhesion between the barrier layer and the mask forming layer (or mask layer) can be improved. Therefore, when forming a mask by selectively removing a part of the mask formation layer, it is possible to suppress the formation of an erroneous pattern. A printing plate having a high pattern can be produced.

[Example]
(Barrier layer)
A polyamide resin (trade name “Macromelt 6900” manufactured by Henkel Co., Ltd.) was dissolved in a mixed solution of toluene / isobutanol = 1/1 to prepare a barrier layer-forming composition comprising a 10% by mass uniform solution. Next, this barrier layer forming composition was applied to a cover sheet made of a polyethylene terephthalate film having a thickness of 100 μm. Then, it dried at 80 degreeC for 5 minute (s), and formed the barrier layer with a film thickness of 4 micrometers.

(Photosensitive layer)
Next, 100 parts by mass of a styrene / butadiene copolymer having a mass average molecular weight of 240,000 (manufactured by JSR Shell Elastomer, trade name “D-1155”), liquid 1,2-polybutadiene having a mass average molecular weight of 1,000 (day 70 parts by mass, trade name “Nisso PB-1000”), 10 parts by mass of trimethylolpropane triacrylate, 3 parts by mass of methoxyphenylacetone, 0.05 of 2,6-di-tert-butyl-4-hydroxytoluene A composition for forming a photosensitive layer was prepared by mixing 0.002 parts by mass of a part by weight, a dye (trade name “Oil Blue # 503” manufactured by Orient Chemical Co., Ltd.) and 0.2 part by mass of tetrahydrofuran.

  This photosensitive layer forming composition is extruded into a polyethylene terephthalate sheet (first support) from a T-die while being kneaded in an extruder with a high viscosity pump, and has a thickness of 1.7 mm. The photosensitive layer was formed.

  Next, the barrier layer and the photosensitive layer were bonded using a laminating roller to obtain a “first laminate” composed of a first support, a photosensitive layer, and a barrier layer.

(Mask formation layer)
Next, a polyamide resin (trade name “Macromelt 6900” manufactured by Henkel Co., Ltd.) was dissolved in toluene / isobutanol = 1/1 to prepare a 10% by mass uniform solution. Carbon black with a solid content concentration of 30% by mass (trade name “MHI Black # 217” manufactured by Mikuni Dye Co., Ltd.) is added to the solution so that the carbon black is 30 parts by mass relative to the polyamide resin, and the mask forming layer is used. A composition was prepared.

  Next, this mask forming layer composition is applied onto a cover sheet (second support) made of a polyethylene terephthalate film having a thickness of 100 μm and dried at 80 ° C. for 5 minutes to form a mask having a thickness of 2 μm. A layer was formed. Through the above steps, a second laminate comprising a polyethylene terephthalate film and a mask forming layer was obtained.

(Lamination)
Next, the polyethylene terephthalate film in contact with the barrier layer of the first laminate is peeled off, and the laminating roller is moved so that the exposed surface of the barrier layer faces the exposed surface of the mask forming layer of the second laminate. Using the laminate, a printing plate precursor according to the example was obtained.

(Evaluation)
Next, using the printing plate precursor according to the example, back exposure of 75 mJ / cm ² was performed from the photosensitive layer side. Next, the cover sheet (second support) is peeled off, fixed to a NIR laser writing device (CDI-spark, manufactured by Esco-Flufffix), rotated at 800 rpm, and using a NIR laser with an energy of 19 W, the resolution The mask formation layer was selectively removed by laser irradiation so as to obtain 2540 dpi.

  When the F1 from which the cover sheet was peeled was handled, no peeling between the barrier layer and the mask layer was observed, and no peeling was observed on the thin line of the non-removed portion of the mask layer after the NIR laser irradiation.

[Comparative example]
(Preparation of printing plate master)
A printing plate precursor according to a comparative example in the same manner as in the example except that the polyamide resin in the composition for the mask forming layer in the example was changed to ethyl cellulose (trade name “Etocel STD7” manufactured by Shin-Etsu Chemical Co., Ltd.). Got.

(Evaluation)
A part of the mask formation layer was selectively removed by the same method as in the example. When handling F2 from which the cover sheet was peeled off, partial peeling was observed between the mask layer and the barrier layer, and some peeling was also observed on the thin lines of the non-removed portion of the mask layer after NIR laser irradiation. It was.

  As described above, it was confirmed that in the printing plate precursor according to the example, the barrier layer and the mask layer were not peeled as compared with the comparative example, and a printing plate having a highly accurate pattern could be produced. .

  In various letterpress printing methods, a useful printing plate precursor can be provided.

Claims (7)

A photosensitive layer;
A barrier layer provided on the photosensitive layer;
A mask forming layer provided on the barrier layer and removable by irradiating an infrared laser;
A printing plate precursor, wherein 50% by mass or more of the binders contained in the barrier layer and the mask forming layer are the same type of binder. A first laminate having a photosensitive layer formed on the first support and a barrier layer provided on the photosensitive layer;
A printing plate precursor comprising: a second laminate having a mask forming layer formed on a second support and removable by irradiating an infrared laser;
A printing plate precursor, wherein 50% by mass or more of the binders contained in the barrier layer and the mask forming layer are the same type of binder.   The printing plate precursor according to claim 1, wherein the binder is a thermoplastic resin.   The printing plate precursor according to claim 3, wherein the thermoplastic resin is an amide resin.   The printing according to any one of claims 1 to 4, wherein the photosensitive layer is provided on a support and contains an elastomeric binder, at least one monomer, and a polymerization initiator. The original edition. A method for producing a printing plate using the printing plate precursor according to any one of claims 1 to 4,
A method for producing a printing plate, wherein the mask forming layer is patterned with an infrared laser. A method for producing a printing plate using the printing plate precursor according to claim 2,
A method for producing a printing plate, comprising: forming a mask layer having a pattern by irradiating an infrared laser on the mask forming layer; and bonding the mask layer to a barrier layer.