JP2012022229A - Photosensitive resin printing original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive resin printing original plate with which a relief image can be formed without using any original image film and the surface adhesiveness of a printing plate can be reduced and the peeling of the relief surface in printing can be suppressed.SOLUTION: A photosensitive resin printing original plate has a photosensitive layer (A) including polyamide having hydrophilic groups and a compound having ethylenic unsaturated bonds; at least one interlayer (B); and a water insoluble thermosensitive mask layer (C) including infrared absorbing materials, which are laminated on a support in this order. The interlayer (B) includes polyvinyl alcohol and/or partially saponified polyvinyl alcohol and polyamide having hydrophilic groups.

Description

  The present invention relates to a photosensitive resin printing plate precursor. More specifically, the present invention relates to a photosensitive resin printing plate precursor used when a resin relief printing plate is produced by computer plate making technology.

  In various printing fields, computer plate making technology (computer-to-plate (CTP) technology) known as digital image forming technology has become common. As one of the CTP technologies, a thermal mask layer that is opaque to ultraviolet light is provided in advance on a photosensitive resin layer, and the thermal mask layer is ablated by irradiating the thermal mask layer with an infrared laser. There is a method of forming.

  As a photosensitive resin printing plate precursor used in CTP technology, a photosensitive resin layer (A) containing a resin that can be dissolved or dispersed in water and a monomer curable by ultraviolet light on a support, dissolved or dispersed in water A photosensitive resin printing plate precursor is proposed in which an adhesive strength adjusting layer (B) containing a possible resin and a water-insoluble thermal mask layer (C) containing an infrared absorbing material are laminated in this order. (For example, refer to Patent Document 1). Furthermore, as means for suppressing the generation of wrinkles on the heat-sensitive mask layer, for example, a photosensitive resin printing plate precursor containing a partially saponified polyvinyl acetate having an saponification degree of 60 mol% or more (for example, Patent Document 2) And a photosensitive resin printing plate precursor in which the adhesion adjusting layer contains an amine compound has been proposed (see, for example, Patent Document 3).

JP 2004-163925 A JP 2005-326442 A JP 2009-139598 A

  When an intermediate layer such as an adhesive strength adjusting layer having a polarity similar to that of the photosensitive resin layer is provided between the photosensitive resin layer and the thermal mask layer, the photosensitive resin component moves to the intermediate layer over time, and exposure and development are performed. In some cases, the intermediate layer may remain on the surface of the printing plate produced through the above process. In general, polyvinyl alcohol and partially saponified polyvinyl alcohol have a high degree of crystallinity and little tackiness. Therefore, when an intermediate layer containing these remains on the printing plate surface, the surface tackiness is low, and the surface of the plate at the time of printing is reduced. Dust adhesion and the like are suppressed, and a high-quality printed matter can be obtained. However, when the photosensitive resin layer contains a polyamide having a hydrophilic group, the adhesion between the intermediate layer containing polyvinyl alcohol and / or partially saponified polyvinyl alcohol and the photosensitive resin layer is low. It has been found that there is a problem that the quality of the printed matter is deteriorated, for example, the peeled intermediate layer component adheres to the printed matter.

  In view of the above problems, the object of the present invention is to form a relief image without the need for an original film, and to reduce the surface tackiness of the printing plate and the peeling of the relief surface during printing. It is to provide a photosensitive resin printing plate precursor.

  In order to solve the above problems, the present invention mainly has the following configuration. That is, a photosensitive resin layer (A) containing a hydrophilic group-containing polyamide and a compound having an ethylenically unsaturated bond, at least one intermediate layer (B), and a water-insoluble containing an infrared absorbing substance on the support. The photosensitive resin printing plate precursor having the heat-sensitive mask layers (C) in this order, wherein the intermediate layer (B) contains polyvinyl alcohol and / or partially saponified polyvinyl alcohol, and polyamide having a hydrophilic group. And a photosensitive resin printing plate precursor.

  According to the photosensitive resin printing plate precursor of the present invention, it is possible to form a relief image without requiring an original image film, and to reduce the surface tackiness of the printing plate and the peeling of the relief surface during printing. Can do. For this reason, a high-quality printed matter can be obtained easily.

  Embodiments of the present invention will be described below.

  The photosensitive resin printing plate precursor of the present invention has a photosensitive resin layer (A), an intermediate layer (B), and a thermal mask layer (C) in this order on a support. Each layer may have two or more layers.

  The support in the present invention is preferably dimensionally stable, and examples thereof include metal plates such as steel, stainless steel and aluminum, plastic sheets such as polyester, and synthetic rubber sheets such as styrene-butadiene rubber. Moreover, what gave the surface easy adhesion processing which improves adhesiveness with the photosensitive resin layer (A) may be given, and you may have an adhesive layer on the surface. The thickness of the support is preferably 50 μm to 1 mm. When it has an adhesive layer, the thickness of the adhesive layer is preferably 1 to 100 μm.

  The photosensitive resin layer (A) in the present invention contains a polyamide having a hydrophilic group and a compound having an ethylenically unsaturated bond, and is photocured by irradiation with ultraviolet light, preferably 300 to 400 nm. Further, it preferably contains a photopolymerization initiator. The photosensitive resin layer (A) is preferably formed from a photosensitive resin composition and molded into a sheet having a thickness of 0.1 to 10 mm.

  The photosensitive resin layer (A) in the present invention contains a polyamide having a hydrophilic group. Such a polyamide has a function as a carrier resin for maintaining the form of the photosensitive resin composition in a solid state, and for imparting developability of the photosensitive resin layer (A) with water or alcohol. used.

  Examples of hydrophilic groups include hydroxyl groups, carboxyl groups and salts thereof, alkyleneoxy groups (such as ethyleneoxy groups, poly (ethyleneoxy) groups, propyleneoxy groups, poly (propyleneoxy) groups), amino groups, ammonium groups, and sulfones. Examples include acid groups and salts thereof, phosphate groups and salts thereof, and the like.

  As such a polyamide having a hydrophilic group, a polyamide having a hydrophilic group in the main chain or side chain is preferable. For example, a copolymerized polyamide obtained by copolymerizing ε-caprolactam and a component having a hydrophilic group, Examples thereof include a modified polyamide in which a hydrogen atom is substituted with a hydrophilic group. Such polyamide may have an ester bond or a urethane bond in addition to the amide bond.

Examples of the copolyamide include a polyamide having a sulfonic acid group or a salt thereof in a side chain described in JP-A-48-72250, and a poly ( A copolymer polyamide having an ethyleneoxy) group, a copolymer polyesteramide having a poly (ethyleneoxy) group described in JP-A-58-117537, a base described in JP-A-50-7605 And polyamide having reactive nitrogen. Examples of the modified polyamide include a methoxymethyl group (—CH 2) wherein at least a part of hydrogen atoms of an amide bond (—NHCO—) of a polyamide or copolymer polyamide described in JP-A-39-3143 is used. _And N-methoxymethylated polyamide substituted with ₂ OCH ₃ ). Two or more of these may be contained.

  Among the polyamides, polyamides having an amino group in the main chain or side chain, such as those having a piperazine ring, and polyamides having a polyether segment (poly (alkyleneoxy) group) such as polyethylene glycol are preferably used.

  In the present invention, the content of the polyamide having a hydrophilic group in the photosensitive resin layer (A) is preferably 30% by weight to 70% by weight in the total solid content of the photosensitive resin layer (A).

  The photosensitive resin layer (A) in the present invention contains a compound having an ethylenically unsaturated bond. A compound having an ethylenically unsaturated bond is generally crosslinked by radical polymerization. As a compound which has an ethylenically unsaturated bond, the compound which has an acryl group and / or a methacryl group is mentioned, for example. Specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-chloro-2-hydroxypropyl (meth) acrylate, β-hydroxy-β '-(Meth) acryloyloxyethyl phthalate and other hydroxyl group-containing (meth) acrylates, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, lauryl (meth) acrylate, alkyl (meth) acrylate such as stearyl (meth) acrylate, cycloalkyl (meth) acrylate such as cyclohexyl (meth) acrylate, chloroe Alkyl alkyl (meth) acrylates such as chill (meth) acrylate and chloropropyl (meth) acrylate, alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, and butoxyethyl (meth) acrylate , Phenoxyalkyl (meth) acrylates such as phenoxyethyl acrylate, nonylphenoxyethyl (meth) acrylate, alkoxyalkylene glycols such as ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate (Meth) acrylate, (meth) acrylamide, diacetone (meth) acrylamide, N, N′-methylenebis (Meth) acrylamides such as (meth) acrylamide, 2,2-dimethylaminoethyl (meth) acrylate, 2,2-diethylaminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N- Compounds having only one ethylenically unsaturated bond such as dimethylaminopropyl (meth) acrylamide, polyethylene glycol di (meth) acrylate such as diethylene glycol di (meth) acrylate, polypropylene glycol such as dipropylene glycol di (meth) acrylate Di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, glycerol tri (meth) Such as polyvalent (meth) acrylates and glycidyl (meth) acrylates obtained by addition reaction of acrylates, ethylene glycol diglycidyl ether with compounds with ethylenically unsaturated bonds and active hydrogen such as unsaturated carboxylic acids and unsaturated alcohols Polyhydric (meth) acrylamides such as polyvalent (meth) acrylates and methylenebis (meth) acrylamides obtained by the addition reaction of unsaturated epoxy compounds with compounds having active hydrogen such as carboxylic acids and amines, and many compounds such as divinylbenzene. And compounds having two or more ethylenically unsaturated bonds, such as a valent vinyl compound. Two or more of these may be contained. In the text, (meth) acrylate means acrylate or methacrylate, and (meth) acryl means acryl or methacryl.

  In the present invention, the content of the compound having an ethylenically unsaturated bond in the photosensitive resin layer (A) is preferably 15% by weight to 55% by weight in the total solid content of the photosensitive resin layer (A).

  The photosensitive resin layer (A) in the present invention preferably contains a photopolymerization initiator. By containing a photopolymerization initiator capable of polymerizing a polymerizable carbon-carbon unsaturated group by light, the compound having an ethylenically unsaturated bond is crosslinked by irradiation with ultraviolet light, and a photosensitive resin layer is formed. It can be easily photocured. As the photopolymerization initiator, those having a function of generating radicals by self-cleavage or hydrogen abstraction are preferable. Examples of such photopolymerization initiators include benzoin alkyl ethers, benzophenones, anthraquinones, benzyls, acetophenones, diacetyls, and the like. Two or more of these may be contained.

  In the present invention, the content of the photopolymerization initiator in the photosensitive resin layer (A) is preferably 0.5% by weight to 5% by weight in the total solid content of the photosensitive resin layer (A).

  The photosensitive resin layer (A) may contain, as other components, polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, trimethylolpropane, and trimethylolethane. Solubility and flexibility can be improved. Further, for example, a conventionally known polymerization inhibitor such as phenols, hydroquinones, catechols and the like may be contained, and the thermal stability can be improved. Moreover, dye, a pigment, surfactant, a ultraviolet absorber, a fragrance | flavor, antioxidant, etc. can also be contained.

The heat-sensitive mask layer (C) in the present invention (1) efficiently absorbs an infrared laser, and part or all of the layer is evaporated or ablated by the heat. It has a function of causing a difference in optical density, that is, a function of reducing the optical density of the irradiated portion, and (2) a function of practically blocking ultraviolet light. The term “cutting off the ultraviolet light” here means that the optical density of the thermal mask layer (C) is 2.0 or more, and more preferably 2.5 or more. The optical density is generally represented by D and is defined by the following equation.
D = log ₁₀ (100 / T) = log ₁₀ (I ₀ / I)
(Here, T is the transmittance (unit:%), I ₀ is the incident light intensity when measuring the transmittance, and I is the transmitted light intensity.)

  For optical density measurement, there are known methods of calculating from the measured value of transmitted light intensity with a constant incident light intensity and calculating from the measured value of incident light intensity required to reach a certain transmitted light intensity. However, the optical density in the present invention is a value calculated from the former transmitted light intensity. The optical density can be measured with a Macbeth transmission densitometer “TR-927” (manufactured by Kolmorgen Instruments Corp.) using an orthochromatic filter.

  The thermal mask layer (C) contains an infrared absorbing material. Further, it may contain a thermally decomposable compound that is evaporated or ablated by heat and an ultraviolet absorbing material that blocks ultraviolet light.

  The infrared absorbing substance is not particularly limited as long as it is a substance that can absorb infrared light and convert it into heat. For example, black pigments such as carbon black, aniline black and cyanine black, green pigments such as phthalocyanine and naphthalocyanine, rhodamine dye, naphthoquinone dye, polymethine dye, diimonium salt, azoimonium dye, chalcogen dye, carbon graphite, Diamine-based metal complexes, dithiol-based metal complexes, phenolthiol-based metal complexes, mercaptophenol-based metal complexes, arylaluminum metal salts, crystal water-containing inorganic compounds, copper sulfate, chromium sulfide, silicate compounds, titanium oxide, vanadium oxide, Examples thereof include metal oxides such as manganese oxide, iron oxide, cobalt oxide and tungsten oxide, hydroxides and sulfates of these metals, and metal powders of bismuth, tin, tellurium, iron and aluminum. Two or more of these may be contained.

  Among these, carbon black is particularly preferable from the viewpoint of photothermal conversion efficiency, economic efficiency, handleability, and an ultraviolet absorption function described later. Carbon black is classified into furnace black, channel black, thermal black, acetylene black, lamp black and the like according to its production method. Among these, furnace black is preferably used because various types of furnace black are commercially available in terms of particle size and other aspects and are commercially inexpensive.

  In the present invention, the content of the infrared absorbing substance in the heat-sensitive mask layer (C) is preferably 2% by weight or more in the total solid content of the heat-sensitive mask layer (C) from the viewpoint of photothermal conversion efficiency, and more preferably 5% by weight or more. preferable. On the other hand, from the viewpoint of scratch resistance of the thermal mask layer (C), it is preferably 75% by weight or less, more preferably 70% by weight or less.

  Examples of the thermally decomposable compound preferably used for the layer (C) include, for example, a polymer compound and a nitro compound that are easily thermally decomposed, an organic peroxide, an azo compound, a diazo compound, a hydrazine derivative, and an infrared absorbing substance. Listed metals or metal oxides can be mentioned. Two or more of these may be contained. From the viewpoint of coatability, a polymer compound is preferable, and examples thereof include an acrylic resin. Acrylic resins are relatively easy to thermally decompose, and the general thermal decomposition temperature of acrylic resins is 190 ° C to 250 ° C. The acrylic resin refers to a polymer or copolymer of one or more monomers selected from the group consisting of acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. Among the acrylic resins, by selecting a grade that does not dissolve in water or alcohol, mass transfer to the lower photosensitive resin layer (A) can be suppressed. Therefore, a water / alcohol insoluble acrylic resin is more preferable. Used. In the present invention, the content of the thermally decomposable compound in the thermal mask layer (C) is preferably 20 to 50% by weight in the total solid content of the thermal mask layer (C).

  Although it does not specifically limit as an ultraviolet-absorbing substance used preferably for a layer (C), Preferably, it is a compound which has absorption in the area | region of 300 nm-400 nm. For example, benzotriazole-based compounds, triazine-based compounds, benzophenone-based compounds, carbon black, and metals or metal oxides listed in infrared absorbing materials can be used. Two or more of these may be contained. Among these, carbon black is particularly preferably used because it has absorption characteristics not only in the ultraviolet light region but also in the infrared light region and functions as a photothermal conversion substance. In the present invention, the content of the ultraviolet absorbing substance in the thermal mask layer (C) is preferably 10 to 40% by weight in the total solid content of the thermal mask layer (C).

  The heat-sensitive mask layer (C) used in the present invention is insoluble in water. The term “water-insoluble” as used herein means that the heat-sensitive mask layer (C) alone does not dissolve or disperse in water but maintains the film shape in water. Specifically, when the photosensitive resin printing plate precursor or the heat-sensitive mask layer (C) is immersed in water at 25 ° C., the heat-sensitive mask layer (C) maintains the film shape without dissolving for 24 hours or more. Say. By making the thermal mask layer (C) water-insoluble, swelling of the thermal mask layer (C) can be suppressed even in a high humidity (relative humidity of 70% or more) environment. Further, when the heat-sensitive mask layer (C) is dissolved or dispersed in water, the polarity is similar to that of the photosensitive resin layer (A) or intermediate layer (B) containing polyamide having a hydrophilic group. Movement may occur, reducing the function unique to each layer. For example, (1) When a compound having an ethylenically unsaturated bond in the photosensitive resin layer (A) moves to the thermal mask layer (C), the laser ablation of the thermal mask layer (C) is impaired. (2) If an ultraviolet absorbing substance is mixed in the photosensitive resin layer (A), curing by ultraviolet light is inhibited, but the above phenomenon occurs when the thermal mask layer (C) is insoluble in water. Hard to do.

  The method for imparting water insolubility to the thermal mask layer (C) is not particularly limited, and examples thereof include a method of constituting the entire composition of the thermal mask layer (C) with a hydrophobic component, a method of crosslinking a curable resin, and the like. Can do. The latter method is preferable because the effect of making the intermolecular mass transfer less likely to occur and the effect of imparting scratch resistance to the thermal mask layer (C) are obtained by polymerizing the components constituting the thermal mask layer (C). .

  When a curable resin is used for the thermal mask layer (C), the crosslinking method of the resin is not particularly limited, but photocuring in the thermal mask layer (C) that practically blocks ultraviolet light is difficult or inefficient, and thermosetting Is preferred. Examples of the thermosetting resin include epoxy resins, melamine resins, urethane resins, crosslinkable polyester resins, and crosslinkable polyamide resins. Further, it comprises at least one compound selected from the group consisting of polyfunctional isocyanate compounds and polyfunctional epoxy compounds, and urea resins, amine compounds, amide compounds, hydroxyl group-containing compounds, carboxylic acid compounds, and thiol compounds. A combination with at least one compound selected from the group can be mentioned. Two or more of these may be contained.

  When a polyfunctional isocyanate compound is used, the reaction is not completed in a short time, so it is necessary to cure at a high temperature. However, when nitrocellulose is used as the thermally decomposable compound, the decomposition temperature is 180 ° C. There is a restriction that curing cannot be performed at the above temperature. Therefore, as a crosslinking method, a combination of a polyfunctional epoxy compound and at least one compound selected from the group consisting of a urea resin, an amine compound, an amide compound, a hydroxyl group-containing compound, a carboxylic acid compound, and a thiol compound is used. Are preferably used.

  Examples of the polyfunctional epoxy compound include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and glycidyl ether type epoxy resin.

  Examples of urea-based resins include butylated urea resins, butylated melamine resins, butylated benzoguanamine resins, butylated urea melamine cocondensation resins, aminoalkyd resins, iso-butylated melamine resins, methylated meminin resins, hexaxins. Examples include methoxymethylol melamine, methylated benzoguanamine resin, butylated benzoguanamine resin. Examples of the amine compound include diethylenetriamine, triethylenetriamine, tetraethylenepentamine, diethylaminopropylamine, N-aminoethylpiperazine, metaxylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and isophoronediamine. . Examples of amide compounds include polyamide curing agents and dicyandiamide that are used as curing agents for epoxy resins. Examples of the hydroxyl group-containing compound include a phenol resin and a polyhydric alcohol. Examples of the carboxylic acid compound include phthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, dodecinyl succinic acid, pyromellitic acid, chlorenic acid, maleic acid, fumaric acid, and anhydrides thereof. Examples of the thiol compound include polyvalent thiols.

  The content of these thermosetting resins is preferably 0.5% by weight or more, more preferably 1.0% by weight or more in the heat-sensitive mask layer (C) from the viewpoint of forming a crosslinked structure sufficient to impart water insolubility. More preferred. On the other hand, from the viewpoint of easily removing the thermal mask layer (C), it is preferably 20% by weight or less, more preferably 10% by weight or less in the thermal mask layer (C).

  When a pigment such as carbon black is used as the infrared absorbing material, a plasticizer, a surfactant or a dispersion aid may be contained in order to facilitate the dispersion.

  The film thickness of the thermal mask layer (C) is preferably 0.5 to 5 μm.

  The photosensitive resin printing plate precursor of the present invention contains at least one polyvinyl alcohol and / or partially saponified polyvinyl alcohol and polyamide having a hydrophilic group between the photosensitive resin layer (A) and the heat-sensitive mask layer (C). It has a middle layer (B) of the layers. You may have two or more intermediate layers. For example, when the adhesion between the intermediate layer (B1) in contact with the heat-sensitive mask layer (C) and the photosensitive resin layer (A) is insufficient, the heat-sensitive resin layer (A) and the two layers are between It is also possible to further form an intermediate layer (B2) that is more excellent in adhesion. By providing the above-mentioned intermediate layer, each of the photosensitive resin layer (A), the intermediate layer (B), and the thermal mask layer (C) containing a polyamide having a hydrophilic group and a compound having an ethylenically unsaturated bond, in particular. It is possible to optimize the adhesion between the layers and suppress the peeling of the relief surface during printing. Further, by containing a polyamide having a hydrophilic group, the intermediate layer (B) having a polarity similar to that of the photosensitive resin layer (A) has a low molecular weight ethylenic unsaturated component among the components constituting the photosensitive resin layer. A compound containing a bond or a photopolymerization initiator tends to migrate. As a result, the intermediate layer (B) containing polyvinyl alcohol and / or partially saponified polyvinyl alcohol having a high degree of crystallinity and low tackiness also remains on the surface of the printing plate produced through exposure and development. The surface tackiness is suppressed.

  The intermediate layer remaining on the printing plate surface is composed of functional group analysis by FT-IR analysis of the printing plate surface, fragment analysis of surface composition by time-of-flight secondary ion mass spectrometry (TOF-SIMS), scanning electron microscope (SEM) And / or by analyzing the cross section of the printing plate with a transmission electron microscope (TEM).

  As the polyvinyl alcohol and / or partially saponified polyvinyl alcohol used for the intermediate layer (B), those having compatibility with polyamide having a hydrophilic group are preferable. The term “compatible” as used herein refers to a solution in which polyvinyl alcohol and / or partially saponified polyvinyl alcohol is dissolved in a mixed solvent of water and alcohol, and a solution in which polyamide having a hydrophilic group is dissolved in a mixed solvent of water and alcohol. The mixed solution is not in phase separation after 24 hours. By combining highly compatible resins, the adhesion between the intermediate layer (B) and the photosensitive resin layer (A) or the thermal mask layer (C) becomes uniform, and the surface tackiness of the printing plate and the relief during printing Surface peeling can be stably suppressed. Further, since the intermediate layer (B) and the photosensitive resin layer (A) are in close contact with each other, partial peeling between the two layers can be suppressed, and the thermal mask layer (C) can be prevented from being broken.

  The polyvinyl alcohol and / or partially saponified polyvinyl alcohol used for the intermediate layer 1 (B1) in contact with the heat-sensitive mask layer (C) preferably has a saponification degree of 60 mol% or more. If the saponification degree is 60 mol% or more, a strong intermediate layer (B) film is formed by hydrogen bonding, so that swelling due to a compound having an ethylenically unsaturated bond, which is a component of UV ink, is reduced. Separation of the relief surface can be further suppressed. Moreover, the adhesiveness of the printing plate surface can be further reduced. More preferably, the saponification degree is 75% or more. The intermediate layer 1 (B1) refers to the intermediate layer when it has only one intermediate layer, and the thermal mask layer (C) among the plurality of intermediate layers when it has two or more intermediate layers. Refers to the layer located on the side. The degree of saponification can be measured by the method shown in JIS K6726 (1994).

  Among the intermediate layers (B), the polyvinyl alcohol and / or partially saponified polyvinyl alcohol used for the intermediate layer 1 (B1) in contact with the heat-sensitive mask layer (C) has a side chain and / or a terminal carboxyl group. More preferred. Since it has a carboxyl group, it forms a strong intermediate layer (B) film by forming an ionic bond with a polyamide having a hydrophilic group, preferably a polyamide having an amino group, more preferably a polyamide having a piperazine ring. The peeling of the relief surface at the time can be further suppressed. Polyvinyl alcohol or partially saponified polyvinyl alcohol having a carboxyl group at the side chain and / or terminal is obtained by reacting polyvinyl alcohol or partially saponified polyvinyl alcohol with an acid anhydride, and starting from the hydroxyl group of polyvinyl alcohol or partially saponified polyvinyl alcohol. It can be easily obtained by introducing a carboxyl group into the side chain.

  As the polyamide having a hydrophilic group used in the intermediate layer (B), the polyamide exemplified as the polyamide of the photosensitive resin layer is suitable. Examples of hydrophilic groups include hydroxyl groups, carboxyl groups and salts thereof, alkyleneoxy groups (such as ethyleneoxy groups, poly (ethyleneoxy) groups, propyleneoxy groups, poly (propyleneoxy) groups), amino groups, ammonium groups, and sulfones. Examples include acid groups and salts thereof, phosphate groups and salts thereof, and the like. Among these hydrophilic groups, an alkyleneoxy group and an amino group are preferable, and a piperazine ring is more preferable.

As the polyamide having such a hydrophilic group, those having a hydrophilic group in the main chain or side chain are preferable. For example, a polyamide having a sulfonic acid group or a salt thereof in the side chain, a copolymer polyamide having a poly (ethyleneoxy) group , Copolyesteramide having a poly (ethyleneoxy) group, polyamide having an amino group such as a piperazine ring, and at least a part of hydrogen atoms of an amide bond (—NHCO—) is substituted with a methoxymethyl group (—CH ₂ OCH ₃ ) N-methoxymethylated polyamide and the like. Two or more of these may be contained.

  Among the polyamides, polyamides having amino groups in the main chain or side chains and polyamides having polyether segments (poly (alkyleneoxy) groups) such as polyethylene glycol are preferably used. Among polyamides having an amino group, polyamides having a piperazine ring are more preferable. By using such a polyamide, printing is performed to form a strong intermediate layer (B) film by forming an ionic bond with polyvinyl alcohol having a carboxyl group at the side chain and / or terminal and / or partially saponified polyvinyl alcohol. The peeling of the relief surface at the time can be further suppressed. Moreover, the adhesiveness of the printing plate surface can be further reduced, and the blur of the printed matter can be reduced.

  The intermediate layer 2 (B2) in contact with the photosensitive resin layer (A) preferably contains a polyamide having a hydrophilic group. By such an intermediate layer 2 (B2), the adhesiveness with the photosensitive resin layer (A) is further improved, peeling of the relief surface during printing is further suppressed, and a high-quality printed matter can be easily obtained. The intermediate layer 2 (B2) refers to the intermediate layer when the intermediate layer has only one intermediate layer. When the intermediate layer 2 (B2) includes two or more intermediate layers, the most photosensitive resin layer (A ) Refers to the layer located on the side. In addition, when adhesion with the above-mentioned intermediate | middle layer (B1) and photosensitive resin layer (A) is inadequate, the intermediate | middle layer (B2) which is excellent by adhesion with the photosensitive resin layer (A) between both layers Is preferably further formed. Thereby, peeling between an intermediate | middle layer (B) and the photosensitive resin layer (A) can be suppressed, and the tear of a thermal mask layer (C) can be suppressed.

  In the present invention, the content of the polyamide having a hydrophilic group in the intermediate layer (B) is preferably 10 to 100 parts by weight with respect to 100 parts by weight of polyvinyl alcohol and / or partially saponified polyvinyl alcohol. By setting the content of the polyamide having a hydrophilic group to 10 parts by weight or more, the adhesion between the intermediate layer (B) and the photosensitive resin layer (A) is improved, and relief surface peeling during printing can be further suppressed. Moreover, peeling between an intermediate | middle layer (B) and the photosensitive resin layer (A) can be suppressed, and the tear of a thermal mask layer (C) can be suppressed. More preferably, it is 15 parts by weight or more. Moreover, the surface adhesiveness of a printing plate can be reduced more by setting it as 100 weight part or less. More preferably, it is 50 parts by weight or less.

  Among the intermediate layer (B), the content of polyamide having a hydrophilic group in the intermediate layer 1 (B1) in contact with the heat-sensitive mask layer (C) is polyvinyl alcohol and / or as described for the intermediate layer (B). Or 10 to 100 weight part is preferable with respect to 100 weight part of content of partially saponified polyvinyl alcohol. On the other hand, when the intermediate layer (B) has two or more layers, the content of polyamide having a hydrophilic group in the intermediate layer 2 (B2) in contact with the photosensitive resin layer (A) further suppresses relief surface peeling during printing. In view of the above, the content is preferably 50 parts by weight or more, more preferably 100 parts by weight or more with respect to 100 parts by weight of the content of polyvinyl alcohol and / or partially saponified polyvinyl alcohol.

  The intermediate layer (B) may contain a compound having an ethylenically unsaturated bond, a photopolymerization initiator, a plasticizer, and a surfactant.

  In the present invention, the film thickness of the intermediate layer (B) is preferably 15 μm or less, more preferably 5 μm or less, from the viewpoint of suppressing light bending and scattering during exposure and obtaining a sharp relief. On the other hand, 0.05 μm or more is preferable from the viewpoint of easily forming the intermediate layer (B). Examples of the method for measuring the film thickness include a method of measuring by a film weight per unit area and a method of measuring by a micrometer.

  The photosensitive resin printing plate precursor of the present invention has the heat-sensitive resin layer (A), at least one intermediate layer (B), and a heat-sensitive mask layer (C) in this order on a support. If necessary, a cover film (E) may be further provided on the heat-sensitive mask layer (C). By having the cover film (E), the heat-sensitive mask layer (C) can be protected from external damage. The cover film (E) is preferably peelable from the heat-sensitive mask layer (C). For example, a film such as polyester, polycarbonate, polyamide, fluoropolymer, polystyrene, polyethylene, polypropylene, or a release paper coated with silicone. Is mentioned.

  The film thickness of the cover film (E) is preferably 25 μm or more, and more preferably 50 μm or more. If it is this range, handling will be easy and a thermal mask layer (C) can be easily protected from an injury. On the other hand, from an economical viewpoint, 200 μm or less is preferable, and 150 μm or less is more preferable. The film thickness of the cover film (E) can be measured with a micrometer.

  The photosensitive resin printing plate precursor of the present invention may further include (D) a peeling auxiliary layer between the thermal mask layer (C) and the cover film (E). The peeling auxiliary layer (D) has a function of easily peeling only the peeling auxiliary layer (D) or only the cover film (E) or both the cover film (E) and the peeling auxiliary layer (D) from the photosensitive resin printing plate precursor. It is preferable to have. If the cover film (E) and the thermal mask layer (C) are directly laminated and the adhesive strength between the two layers is strong, the cover film (E) cannot be peeled off or may be peeled off together with the thermal mask layer (C). There is sex.

  Therefore, the peeling auxiliary layer (D) has a strong adhesive force with the thermal mask layer (C) and is weak enough to peel the adhesive force with the cover film (E), or with the thermal mask layer (C). It is preferable that the adhesive force is weak enough to be peeled off and is made of a substance having a strong adhesive force with the cover film (E). In addition, after peeling a cover film (E), since a peeling auxiliary | assistant layer (D) may remain on the thermal mask layer (C) side and may become an outermost layer, it is preferable that it is not adhesive from the surface of handling. Moreover, since it exposes to ultraviolet light through a peeling auxiliary layer (D), it is preferable that it is substantially transparent.

  The material used for the peeling auxiliary layer (D) can be dissolved or dispersed in water, such as polyvinyl alcohol, polyvinyl acetate, partially saponified polyvinyl alcohol, hydroxyalkyl cellulose, alkyl cellulose, polyamide resin, and the like. It is preferable to use a small amount of resin as a main component. Among these, partially saponified polyvinyl alcohol having a saponification degree of 60 to 99 mol%, hydroxyalkyl cellulose having 1 to 5 carbon atoms in the alkyl group, and alkyl cellulose are particularly preferably used from the viewpoint of tackiness.

  The peeling auxiliary layer (D) may further contain an infrared absorbing substance and / or a thermally decomposable compound in order to facilitate the ablation with infrared rays. As the infrared absorbing material and the thermally decomposable compound, those described above as the components of (C) the heat-sensitive mask layer (C) can be used. Moreover, you may contain surfactant for coating property and wettability improvement.

  The film thickness of the peeling assist layer (D) is preferably 6 μm or less, and more preferably 3 μm or less, from the viewpoint of maintaining the laser ablation of the lower thermal mask layer (C). On the other hand, 0.03 μm or more is preferable from the viewpoint of easily forming the peeling assist layer (D). As a method for measuring the film thickness, a method of measuring by the film weight per unit area is easy.

  When the cover film (E) is peeled from the photosensitive resin printing plate precursor at a speed of 200 mm / min, the peel force per 1 cm width is preferably 0.5 g / cm or more, more preferably 1 g / cm or more. If it is this range, peeling of the protective layer (E) during work can be suppressed. On the other hand, 20 g / cm or less is preferable and 15 g / cm or less is more preferable from the viewpoint of easily peeling the cover film (E).

  Next, the preferable manufacturing method of the photosensitive resin printing plate precursor of this invention is described.

  First, as a method of forming the photosensitive resin layer (A) on the support, for example, a polyamide having a hydrophilic group, a compound having an ethylenically unsaturated bond, if necessary after dissolving other resins in a solvent, necessary Then, a photopolymerization initiator and other additives are added and stirred sufficiently to obtain a photosensitive resin composition solution. After removing the solvent from this solution, it is preferably melt extruded onto a support coated with an adhesive. Can be obtained. Alternatively, the photosensitive resin composition solution in which a part of the solvent remains can be obtained by melt-extrusion onto a support on which an adhesive is applied, and the remaining solvent is naturally dried over time. Although the solvent used for formation of the photosensitive resin layer (A) will not be specifically limited if an intermediate | middle layer (A) component can be melt | dissolved, Water, alcohol, or a mixture thereof is used preferably.

  A method for forming the intermediate layer (B) on the photosensitive resin layer (A) or the heat-sensitive mask layer (C) is not particularly limited, but a solution in which the component of the intermediate layer (B) is dissolved in a solvent for the convenience of thin film formation. Is preferably used on the photosensitive resin layer (A) or the heat-sensitive mask layer (C) to remove the solvent. Although the solvent used for formation of an intermediate | middle layer (B) will not be specifically limited if an intermediate | middle layer (B) component can be melt | dissolved, Water, alcohol, or these mixtures are used preferably. Use of water or alcohol is preferable because even if a solution is applied on the water-insoluble heat-sensitive mask layer (C), the heat-sensitive mask layer (C) is not eroded. Further, the boiling point of the solvent under atmospheric pressure is preferably 80 ° C. or higher from the viewpoint of suppressing volatilization during coating. On the other hand, 200 ° C. or lower is preferable from the viewpoint of easily removing the solvent.

  When two or more intermediate layers (B) are formed, a solution obtained by dissolving the component of the intermediate layer (B2) in contact with the photosensitive resin layer (A) in a solvent is used as the photosensitive resin layer (A) for the convenience of thin film formation. After applying and removing the solvent, on the intermediate layer (B) including at least the intermediate layer (B2), a solution in which the intermediate layer (B1) component in contact with the thermal mask layer (C) is dissolved in the solvent is applied, and the solvent is removed. Or a solution obtained by dissolving the intermediate layer (B1) component in contact with the thermal mask layer (C) in a solvent on the thermal mask layer (C), removing the solvent, and then removing at least the intermediate layer (B1) The method of apply | coating the solution which melt | dissolved the intermediate | middle layer (B2) component which contact | connects the photosensitive resin layer (A) on the solvent on the intermediate | middle layer (B) containing this, and removing a solvent is used preferably.

  Next, as a method of forming the thermal mask layer (C), for example, a dispersion liquid in which an infrared absorbing material such as carbon black is dispersed in a solvent is prepared, and other thermal mask layer components are used as they are or in an appropriate solvent. A method of mixing with the dissolved solution and applying, removing the solvent and, if necessary, heat curing is preferably used. The solvent used for forming the thermal mask layer (C) is not particularly limited as long as it can dissolve the thermally decomposable compound and the curable resin, which are components of the thermal mask layer (C), but has a boiling point of 80 ° C. under atmospheric pressure. A temperature of 200 ° C. or lower is preferable.

  The method for forming the peeling auxiliary layer (D) on the thermal mask layer (C) or the protective layer (E) is not particularly limited, but a solution in which the peeling auxiliary layer (D) component is dissolved in a solvent for the convenience of thin film formation. Is preferably used on the heat-sensitive mask layer (C) or the protective layer (E) to remove the solvent. Although the solvent used for formation of a peeling auxiliary layer (D) will not be specifically limited if a peeling auxiliary layer (D) component can be melt | dissolved, Water, alcohol, or these mixtures are used preferably.

  By laminating the respective layers, the photosensitive resin printing plate precursor of the present invention can be obtained.

  The first example of the photosensitive resin printing plate precursor of the present invention is a photosensitive resin layer (A), an intermediate layer (B), a thermal mask layer (C), a peeling auxiliary layer (D) and a protective layer on a support. It is an original plate having a structure in which (E) is sequentially laminated. For example, a sheet having a thermal mask layer (C) in which the layer (D), the layer (C) and the layer (B) are laminated on the protective layer (E) by a sequential coating method, and the layer (A) on the support. It can obtain by laminating | stacking the photosensitive resin sheet which laminated | stacked. The laminating method is not particularly limited. For example, the surface of the layer (A) or the layer (B) is swollen with water and / or alcohol, and the thermal mask sheet and the photosensitive resin sheet are bonded to each other, the layer (A) And a method of pouring a high-viscosity liquid having the same or similar composition between a photosensitive resin sheet and a heat-sensitive mask sheet and bonding them together, a method of pressing with a press machine at room temperature or while heating, and the like.

  The second example is an original plate having a structure in which a photosensitive resin layer (A), an intermediate layer (B), and a thermal mask layer (C) are sequentially laminated on a support. For example, a solution of the layer (B) component is applied to a photosensitive resin sheet obtained by laminating the photosensitive resin layer (A) on the support, dried, and then a solution or dispersion of the thermal mask layer (C) component. It can be obtained by applying a liquid and heating to cure. As another method, a sheet having a thermal mask layer (C) in which a layer (C) and a layer (B) are sequentially laminated on a release paper by the same coating method, and a photosensitive material in which the layer (A) is laminated on a support. It can also be obtained by preparing a resin sheet and then laminating the two so that the layer (A) is in contact with the layer (B) and then peeling the release paper. The peeled release paper has the advantage that it can be reused for the same purpose.

  The third example is an original having a structure in which a photosensitive resin layer (A), an intermediate layer (B), a thermal mask layer (C), and a peeling assist layer (D) are sequentially laminated on a support. This original plate can be obtained, for example, by peeling off the protective layer (E) from the original plate obtained in the first example. In this example, there is an advantage that the protective layer (E) can be reused.

  The fourth example is an original plate having a structure in which a photosensitive resin layer (A), an intermediate layer (B), a thermal mask layer (C), and a protective layer (E) are sequentially laminated on a support. For example, a thermal mask sheet in which the layers (C) and (B) are sequentially laminated on the protective layer (E) and a photosensitive resin sheet in which the layer (A) is laminated on the support are laminated. Can be obtained by:

  The photosensitive resin printing plate precursor obtained as described above is at least (1) using the above-described photosensitive resin printing plate precursor, and (2) imagewise irradiating the thermal mask layer (C) with an infrared laser. (3) forming a latent image on the photosensitive resin layer (A) by exposing to ultraviolet light from the formed image mask (C ′) side; 4) A resin relief printing plate can be produced through a process of developing with a liquid containing water as a main component and removing the image mask (C ′) and the photosensitive resin layer (A) in the ultraviolet light unexposed area. it can.

  When the layer (D) and / or the layer (E) is present, at least the layer (E) is peeled off, and then the thermal mask layer (C) is imagewise irradiated with an infrared laser to form an image mask. Preferably, (C ′) is formed. More preferably, the layer (D) and the layer (E) are present, and only the layer (E) is peeled off, and then the thermal mask layer (C) is imagewise irradiated with an infrared laser to form an image mask ( C ′).

  (2) The step of forming an image mask (C ′) by imagewise irradiating the thermal mask layer (C) with an infrared laser is to turn on / off the infrared laser based on image data, This is a step of scanning irradiation with respect to C). When the thermal mask layer (C) is irradiated with an infrared laser, heat is generated by the action of the infrared absorbing material, and the thermal decomposable compound is decomposed by the action of the heat to remove the thermal mask layer (C). Laser ablation. The laser ablated portion has a greatly reduced optical density and is substantially transparent to ultraviolet light. An image mask (C ′) capable of forming a latent image on the photosensitive resin layer (A) is obtained by selectively laser ablating the thermal mask layer (C) based on the image data.

  For the infrared laser irradiation, one having an oscillation wavelength in the range of 750 nm to 3000 nm is used. Examples of such lasers include ruby lasers, alexandrite lasers, perovskite lasers, solid state lasers such as Nd-YAG lasers and emerald glass lasers, semiconductor lasers such as InGaAsP, InGaAs and GaAsAl, and dye lasers such as rhodamine dyes. It is done. A fiber laser that amplifies these light sources with a fiber can also be used. Among them, the semiconductor laser is preferable because it is downsized due to recent technological advances and is economically advantageous over other laser light sources. An Nd-YAG laser is also preferable because it has a high output, is widely used for dentistry and medical purposes, and is economically inexpensive.

  (3) The step of exposing from the image mask (C ′) side using ultraviolet light to form a latent image on the photosensitive resin layer (A) is a photosensitive resin printing plate material that has been laser-irradiated by the above method. In addition, ultraviolet light, preferably ultraviolet light having a wavelength of 300 to 400 nm, is exposed on the entire surface through an image mask (C ′) on which an image is formed by a laser, and the lower part of the laser ablation part in the image mask (C ′) This is a step of selectively photocuring the photosensitive resin layer (A).

  Since ultraviolet light also enters from the side surface of the photosensitive resin printing plate during exposure, it is preferable to cover the side surface with a cover that does not transmit ultraviolet light. As a light source capable of exposing a wavelength of 300 to 400 nm, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a metal halide lamp, a xenon lamp, a carbon arc lamp, a chemical lamp, or the like can be used. The portion of the photosensitive resin layer (A) exposed with ultraviolet light is changed into a substance that cannot be eluted and dispersed by the developer.

  (4) The step of developing with a liquid containing water as a main component to remove the image mask (C ′) and the photosensitive resin layer (A) in the ultraviolet light unexposed area is, for example, the photosensitive resin layer (A). It is achieved by developing using a brush type washing machine having a developer mainly composed of water that can dissolve or disperse water. Through this step, a portion exposed to ultraviolet light remains, and a resin relief printing plate having a relief image is obtained. When the peeling auxiliary layer (D) remains, it is preferably removed in this development step.

  The developer containing water as a main component may contain tap water, distilled water, or water as a main component and an alcohol having 1 to 6 carbon atoms. Here, the main component means 70% by weight or more. Moreover, what mixed the component of the photosensitive resin layer (A), the intermediate | middle layer (B), the thermal mask layer (C), and the peeling auxiliary layer (D) in these liquids can also be used.

  The image mask (C ′) is insoluble in water for the purpose of improving scratch resistance and does not dissolve in a developer composed of water or alcohol. However, since the thin film is superior in terms of cost, it can be physically removed by rubbing with a strong brush such as PBT (polybutylene terephthalate). At this time, the image mask (C ′) can be efficiently removed by using a relatively high temperature developing water of 30 ° C. to 70 ° C.

  Thereafter, if necessary, a treatment for drying the developer adhering to the plate surface, post-exposure of the photosensitive resin printing plate material, an adhesive removal treatment, and the like can be performed.

  The resin relief printing plate produced by the production method of the present invention is preferably used as a resin relief printing plate that can be mounted on a printing machine.

  Hereinafter, the present invention will be specifically described by way of examples.

<Synthesis of water-soluble polyamide 1>
60 parts by weight of an equimolar salt of α, ω-diaminopolyoxyethylene and adipic acid obtained by adding acrylonitrile to both ends of polyethylene glycol having a number average molecular weight of 600 and reducing this with hydrogen, and 20 parts by weight of ε-caprolactam And 20 parts by weight of an equimolar salt of hexamethylenediamine and adipic acid are melt-polymerized to give a water-soluble polyamide 1 having a relative viscosity (viscosity of 1 g of polymer dissolved in 100 ml of chloral hydrate and measured at 25 ° C.) of 2.5. Got. This water-soluble polyamide 1 has a polyethylene glycol segment which is a hydrophilic group in the main chain.

<Synthesis of water-soluble polyamide 2>
10 parts by weight of ε-caprolactam, 90 parts by weight of N- (2-aminoethyl) piperazine and nylon salt of adipic acid, and 100 parts by weight of water were placed in a stainless steel autoclave, and the air inside was replaced with nitrogen gas at 180 ° C. Heating was performed for 1 hour, and then water was removed to obtain water-soluble polyamide 2. This water-soluble polyamide 2 has a piperazine ring which is a hydrophilic group in the main chain.

<Synthesis of modified polyvinyl alcohol 1>
In a flask equipped with a condenser, partially saponified polyvinyl alcohol “GOHSENOL” (registered trademark) KL-05 (degree of saponification measured by the method shown in JIS K6726 (1994), 78.5 mol% to 82.0 mol%, Japan 50 parts by weight of Synthetic Chemical Industry Co., Ltd., 2 parts by weight of succinic anhydride, and 10 parts by weight of acetone were added and heated at 60 ° C. for 6 hours, and then the condenser was removed to volatilize the acetone. Thereafter, the purification step of eluting unreacted succinic anhydride with 100 parts by weight of acetone was performed twice, followed by drying under reduced pressure at 60 ° C. for 5 hours to obtain modified polyvinyl alcohol 1 in which succinic acid was ester-bonded to the hydroxyl group. It was.

<Preparation of composition solution 1 for photosensitive resin layer (A1)>
In a three-necked flask equipped with a stirring spatula and a condenser, (a) 50 parts by weight of water-soluble polyamide 1, (b) 34 parts by weight of water and (c) 22 parts by weight of ethanol were added and stirred at 90 ° C. For 2 hours to dissolve the water-soluble polyamide 1. After cooling to 70 ° C., 1.5 parts by weight of (d) glycidyl methacrylate (“Blemmer” (registered trademark) G, manufactured by NOF Corporation) was added and stirred for 30 minutes. Furthermore, (e) 8 parts by weight of glycerin dimethacrylate (“Blenmer” GMR, manufactured by NOF Corporation), (f) 2-acryloylethyl-2-hydroxyethylphthalic acid (HOA-MPE, Kyoeisha Chemical Co., Ltd.) )) 24 parts by weight, (g) 5 parts by weight of polyethylene glycol (PEG # 400, manufactured by Lion Corporation), (h) N, N, N ′, N′-tetra (2-hydroxy-3-metaacro) Yloxypropyl) -m-xylenediamine 5 parts by weight, (i) tetramethylolmethane triacrylate (“NK ester” A-TMM-3, manufactured by Shin-Nakamura Chemical Co., Ltd.) 4 parts by weight, (j) benzyldimethyl ketal ("Irgacure" (registered trademark) 651, manufactured by Ciba Geigy Co., Ltd.) 1.3 parts by weight and (k) 0.01 parts by weight of hydroquinone monomethyl ether are added. Te was stirred for 30 minutes to obtain a composition solution 1 for a photosensitive resin layer (A1).

<Manufacture of photosensitive resin sheet 1>
Polyester adhesive ("Byron" (registered trademark) 30SS (copolymerized polyester, manufactured by Toyobo Co., Ltd.)) 100 parts by weight on a polyester film "Lumirror" (registered trademark) S10 (manufactured by Toray Industries, Inc.) having a thickness of 250 μm And “Coronate” (registered trademark) L (polyisocyanate, a solution prepared by mixing 3 parts by weight of Nippon Polyurethane Industry Co., Ltd.) with a bar coater to a thickness of 20 μm after drying. The support was formed by drying for a minute.

  The composition solution 1 for the photosensitive resin layer (A1) was cast on the support and dried at 60 ° C. for 2 hours to obtain a photosensitive resin sheet 1 having a thickness of 950 μm including the support. Adjustment of the film thickness of the photosensitive resin sheet 1 was performed by setting a spacer having a predetermined thickness on the support and scraping the portion of the composition solution 1 protruding from the spacer with a horizontal metal scale.

<Preparation of Composition Solution 1 for Peeling Auxiliary Layer (D1)>
11 parts by weight of the partially saponified polyvinyl alcohol “GOHSENOL” KL-05 (degree of saponification measured by the method shown in JIS K6726 (1994) 78.5 mol% to 82.0 mol%, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) It was dissolved in 55 parts by weight of water, 14 parts by weight of methanol, 10 parts by weight of n-propanol and 10 parts by weight of n-butanol to obtain a composition solution 1 for the peeling assist layer (D1).

<Preparation of Composition Solution 1 for Thermal Mask Layer (C1)>
“MA100” (carbon black, manufactured by Mitsubishi Chemical Corporation) 23 parts by weight, “Dianar” (registered trademark) BR-95 (alcohol-insoluble acrylic resin, manufactured by Mitsubishi Rayon Co., Ltd.) 15 parts by weight, plasticizer ATBC A carbon black dispersion 1 was prepared by kneading and dispersing a mixture of 1 part by weight of tributyl acetyl citrate (manufactured by J Plus Co., Ltd.) and 30 parts by weight of methyl isobutyl ketone using a three-roll mill. . In dispersion 1, 1 part by weight of AER6071 (epoxy resin, manufactured by Asahi Kasei Chemicals Corporation), 1 part by weight of “Uban” (registered trademark) 20SE60 (melamine resin, manufactured by Mitsui Chemicals), “light ester” P-1M (Phosphoric acid monomer, manufactured by Kyoeisha Chemical Co., Ltd.) 0.05 parts by weight and 100 parts by weight of methyl isobutyl ketone were added and stirred for 30 minutes to obtain a composition solution 1 for the thermal mask layer (C1).

<Preparation of composition solutions a to l for the intermediate layer (B)>
According to the composition (weight ratio) described in Table 1, the polymer was dissolved in a solvent to obtain a composition solution for the intermediate layer. In addition, the used solvent is the composition solution a to h and j to k for the intermediate layer is a mixed solvent of water: ethanol = 50: 50 (weight ratio), and the composition solution i for the intermediate layer is water: ethanol. = 20:80 (weight ratio) mixed solvent, composition solution 1 for the intermediate layer is ethanol.

  “GOHSENOL” AL-06 in Table 1 is a partially saponified polyvinyl alcohol having a saponification degree of 91.0 mol% to 94.0 mol% (Nippon Synthetic Chemical Industry) measured by the method shown in JIS K6726 (1994). (Made by Co., Ltd.). L-17 is partially saponified polyvinyl alcohol (manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having a saponification degree of 48.0 mol% to 51.0 mol% measured by the method shown in JIS K6726 (1994). . CM-9000 is a polyamide (manufactured by Toray Industries, Inc.) having no hydrophilic group.

<Manufacture of thermal mask element 1>
On the polyester film “Lumirror” S10 (manufactured by Toray Industries, Inc.) having a thickness of 100 μm, the composition solution 1 for the peeling auxiliary layer (D1) was applied with a bar coater so that the dry film thickness was 0.1 μm. It dried at 120 degreeC for 20 second, and obtained the laminated body of peeling auxiliary | assistant layer (D1) / protective layer (E).

  The composition solution 1 for the heat-sensitive mask layer (C1) was applied to the peeling auxiliary layer (D1) side of the laminate thus obtained with a bar coater so that the dry film thickness was 1.0 μm, and 140 ° C. And dried for 20 seconds to obtain a laminate of thermal mask layer (C1) / peeling auxiliary layer (D1) / protective layer (E).

Further, on the heat-sensitive mask layer (C1), the intermediate layer composition solution a was applied with a bar coater so as to have a dry film thickness of 1.0 μm, dried at 120 ° C. for 20 seconds, and the intermediate layer (B− A thermal mask element 1 which is a laminate of a) / thermal mask layer (C1) / peeling auxiliary layer (D1) / protective layer (E) was obtained. The optical density (orthochromatic filter, transmission mode) of this thermal mask element 1 was 2.5. The protective layer (E) was peeled off from the thermal mask element 1 with a cellophane tape, and the laminate of the intermediate layer (Ba) / thermal mask layer (C1) / peeling auxiliary layer (D1) was immersed in 25 ° C. water. However, the heat-sensitive mask layer (C1) was not dissolved even after 1 month and maintained its film shape and was insoluble in water.
Evaluation in each Example and Comparative Example was performed by the following method.

<Compatibility evaluation of polyvinyl alcohol and / or partially saponified polyvinyl alcohol and polyamide having a hydrophilic group>
The composition solution for the intermediate layer was put in a glass bottle and allowed to stand at 25 ° C. for 24 hours, and then the state of the solution was visually observed to evaluate the compatibility. Those in which the solution was not separated into two phases by visual observation were evaluated as having compatibility, and are shown in FIG. On the other hand, when the solution was separated into two phases by visual observation, it was judged that there was no compatibility, and the result was shown as x in Table 1.

<Evaluation of thermal mask layer breakage>
After peeling off the protective layer (E) from the photosensitive resin printing plate precursor obtained in each of the examples and comparative examples, the thermal mask layer (C1) was observed on a light table. When the adhesiveness between the photosensitive resin layer (A) and the intermediate layer (B) is insufficient, the intermediate layer (B) partially peels off together with the protective layer (E) side, and the heat-sensitive mask layer (C1). A tear occurs. The locations of thermal mask layer breakage of 50 μm or more in the 20 cm × 20 cm thermal mask layer were counted. If it is 10 or less, there is no practical problem, but 2 or less is preferable, and 0 is more preferable.

<Evaluation of surface tack of printing plate>
Using the printing plates obtained in each of the examples and comparative examples, printing was performed with LR-3 (Letterpress intermittent rotary label printer, manufactured by Iwasaki Iron Works Co., Ltd.). The ink used was UV161 indigo (manufactured by T & K TOKA Co., Ltd.), the paper used was N mirror (manufactured by Oji Tac Co., Ltd.), and the printing speed was 100 rpm. After printing 1,200 m, the surface of the printing plate was observed with a 10 × optical microscope, and the number of attached dust was counted. If it is 10 or less, there is no practical problem, but 2 or less is preferable, and 0 is more preferable.

<Scratch evaluation of printed matter>
Using the printing plates obtained in each of the examples and comparative examples, printing was performed with LR-3 (Letterpress intermittent rotary label printer, manufactured by Iwasaki Iron Works Co., Ltd.). The ink used was UV161 indigo (manufactured by T & K TOKA Co., Ltd.), the paper used was N mirror (manufactured by Oji Tac Co., Ltd.), and the printing speed was 100 rpm. After printing 1,200 m, the cyan reflection density measured by a Macbeth transmission densitometer “TR-927” (manufactured by Kolmorgen Instruments Corp.) is 1.40 to 1.60 out of a solid portion of 5 cm × 5 cm. The printed matter in the area was observed visually and using a 20 × magnifier. When the printing plate has high surface tackiness or when relief surface peeling occurs, ink loss occurs. Evaluation was performed according to the following evaluation criteria.
○: 50 to 100 μm ink loss on the printed matter is 5 cm × 5 cm and 3 or less Δ: 50 to 100 μm ink loss is 5 cm × 5 cm to 4 to 10 ××: 50 to 100 μm ink loss is 5 cm on the printed matter × 5 cm is more than 10 pieces.

<Relief surface peeling evaluation during printing>
Using the printing plate having a solid portion of 3 cm × 3 cm obtained in each of the examples and comparative examples, it was rotated 20,000 times with an indentation amount of 200 μm by an M-3 printing aptitude tester (manufactured by Miyakoshi Machinery Co., Ltd.). Then, the relief surface of the printing plate was observed with a 10 × optical microscope, and the number of scratches and peelings of 200 μm or more was measured. If it is 10 or less, there is no practical problem, but 2 or less is preferable, and 0 is more preferable.

Example 1
On the photosensitive resin layer (A1) of the above-described photosensitive resin sheet 1, a mixed solvent of water / ethanol = 70/30 wt% is applied using a bar coater # 20 to swell the photosensitive resin layer (A1). And pressure-bonded with a roller so that the heat-sensitive mask layer (C1) of the heat-sensitive mask element 1 is in contact with the photosensitive resin layer (A1), and allowed to stand for one week, and the support / photosensitive resin layer (A1) / intermediate layer ( The photosensitive resin printing plate precursor 1 laminated in the order of Ba) / thermal mask layer (C1) / peeling auxiliary layer (D1) / protective layer (E) was obtained. When the thermal mask layer breakage was evaluated by the above method, no thermal mask layer breakage of 50 μm or more was observed.

Subsequently, the photosensitive resin printing plate precursor from which the protective layer (E) has been peeled off is used as an outer drum type plate setter “CDI SPARK” (manufactured by Esco Graphics Co., Ltd.) equipped with a fiber laser having a light emitting region in the infrared. Then, the support side was mounted so as to be in contact with the drum, and a test pattern (image having a solid portion) having a resolution of 150 lines was drawn, and a thermal mask layer (C1) was formed on the image mask (C1 ′). Under the conditions of a laser output of 6 W and a drum rotation speed of 300 rpm, the solid heat-sensitive mask layer (C1) is substantially laser ablated, and laser excavation or drawing pattern distortion on the surface of the lower photosensitive resin layer (A1) No adverse effects due to excessive laser output occurred. In addition, since the heat-sensitive mask layer (C1) is cross-linked, it is resistant to trauma and easy to handle such as mounting on a plate setter. Subsequently, the entire surface was exposed from the image mask (C1 ′) side with an ultrahigh pressure mercury lamp (manufactured by Oak Co., Ltd.) having a light source in the ultraviolet region (exposure amount: 900 mJ / cm ² ). Subsequently, development was performed for 1.5 minutes with 25 ° C. tap water using a brush type developing machine FTW430II (manufactured by Toray Industries, Inc.) equipped with a brush made of PBT (polybutylene terephthalate). The image mask (C1 ′) and the photosensitive resin layer (A) which is blocked by the image mask and not exposed to ultraviolet rays are selectively developed, and the negative relief is faithfully reproduced with respect to the image mask (C1 ′). Was.

  The resulting relief was not mixed with the black image mask (C1 ') and showed a sharp shape. This is because the heat-sensitive mask layer (C1) is crosslinked and has a water-insoluble property, so that it is not mixed with the hydrophilic photosensitive resin layer (A1).

Further, the obtained relief was dried at 60 ° C. for 10 minutes, and then exposed to the whole surface (exposure amount: 900 mJ / cm ² ) with an ultra-high pressure mercury lamp (manufactured by Oak Co., Ltd.) having a light source in the ultraviolet region. 1 was obtained.

When the surface of the printing plate 1 was analyzed with an FT / IR610 infrared spectrometer (manufactured by JASCO Corporation) equipped with an IRI-30 type micro-infrared infrared attachment device, the surface of the printing plate 1 was partially saponified polyvinyl alcohol. (A signal derived from a hydroxyl group in the vicinity of 3360 cm ⁻¹ and a signal derived from an ester bond in the vicinity of 1740 cm ⁻¹ ) were observed, and it was confirmed that the intermediate layer Ba was retained.

  Table 1 shows the results of evaluating the surface tackiness of the printing plate, the blur of the printed matter, and the relief surface peeling during printing by the above method.

(Examples 2-4, 6-10)
Photosensitive in the same manner as in Example 1, except that the intermediate layer compositions B to i shown in Table 1 were used instead of the intermediate layer composition solution a to form the intermediate layers B to B. A curable resin printing plate precursor and a printing plate were prepared. The evaluation results are shown in Table 2.

(Example 5)
On the heat-sensitive mask layer (C1), the intermediate layer composition solution c was applied with a bar coater so that the dry film thickness was 1.0 μm, and dried at 120 ° C. for 20 seconds to obtain the intermediate layer (Bc). A laminated body of / thermal mask layer (C1) / peeling auxiliary layer (D1) / protective layer (E) was obtained. Thereafter, on the intermediate layer (Bc), the intermediate layer composition solution i was applied with a bar coater so that the dry film thickness was 1.0 μm, and dried at 120 ° C. for 20 seconds. A thermal mask element 2 consisting of -i) / intermediate layer (Bc) / thermal mask layer (C1) / peeling auxiliary layer (D1) / protective layer (E) was obtained.

  A photosensitive resin printing plate precursor and a printing plate were prepared in the same manner as in Example 1 except that the thermal mask element 2 was used in place of the thermal mask element 1. The evaluation results are shown in Table 2.

(Comparative Examples 1-3)
Implemented except that the intermediate layer compositions Bj, Bk, and B-1 are formed using the intermediate layer composition solutions j, k, and l shown in Table 1 instead of the intermediate layer composition solution a. In the same manner as in Example 1, a photosensitive resin printing plate precursor and a printing plate were prepared. However, in Comparative Example 3 using a polyamide having no hydrophilic group in the intermediate layer, a printing plate could not be prepared by the same developing method as in Example 1, so that instead of 25 ° C. tap water as a developer, Ethanol was used. The evaluation results are shown in Table 2.

  As is apparent from Table 2, the intermediate layer (B) contains polyvinyl alcohol and / or partially saponified polyvinyl alcohol, and polyamide having a hydrophilic group, thereby reducing the surface tackiness of the printing plate and relief surface peeling during printing. In addition, a high-quality printed material can be obtained. On the other hand, since Comparative Example 1 does not contain a polyamide having a hydrophilic group in the intermediate layer, the adhesiveness with the photosensitive resin layer (A) is low, and there are problems such as slight thermal mask layer breakage and relief surface peeling during printing. There has occurred. Moreover, the site | part where relief surface peeling generate | occur | produced had high surface adhesiveness, and dust adhesion increased. As a result, blurring occurred in the printed material. Further, in Comparative Example 2 containing no polyvinyl alcohol, the printing plate had a high surface adhesiveness and a large amount of dust adhered, so that scum occurred and a high-quality printed matter could not be obtained. In Comparative Example 3 using polyamide having no hydrophilic group, no intermediate layer remained on the printing plate surface. Further, since the printing plate had high surface adhesiveness and a large amount of dust, high-quality printed matter could not be obtained.

  With the photosensitive resin printing plate precursor of the present invention, it is possible to reduce the surface tackiness of the printing plate and peeling of the relief surface during printing, and to obtain a high-quality printed matter. If a photosensitive resin is used, it can be applied not only to a resin relief plate having a convex relief, but also to a flexographic plate and an intaglio plate, but the application range is not limited thereto.

Claims (6)

A water-insoluble heat-sensitive material containing a photosensitive resin layer (A) containing a polyamide having a hydrophilic group and a compound having an ethylenically unsaturated bond, at least one intermediate layer (B) and an infrared absorbing material on a support. A photosensitive resin printing plate precursor having a mask layer (C) in this order, wherein the intermediate layer (B) contains polyvinyl alcohol and / or partially saponified polyvinyl alcohol, and polyamide having a hydrophilic group. Photosensitive resin printing plate precursor. The photosensitive resin printing plate precursor according to claim 1, wherein the polyamide having a hydrophilic group has an amino group. The photosensitive resin printing plate precursor according to claim 2, wherein the polyamide having an amino group has a piperazine ring. Of the intermediate layer (B), the saponification degree of polyvinyl alcohol and / or partially saponified polyvinyl alcohol contained in the intermediate layer (B1) in contact with the thermal mask layer (C) is 60 mol% or more. The photosensitive resin printing plate precursor in any one of Claims 1-3. Of the intermediate layer (B), the polyvinyl alcohol and / or partially saponified polyvinyl alcohol contained in the intermediate layer (B1) in contact with the thermal mask layer (C) has a carboxyl group at the side chain and / or terminal. The photosensitive resin printing plate precursor as claimed in any one of claims 1 to 4, wherein The photosensitive layer according to any one of claims 1 to 5, wherein the intermediate layer (B2) in contact with the photosensitive resin layer (A) among the intermediate layer (B) contains polyamide having a hydrophilic group. Resin printing plate precursor.