Flexographic printing original plate, method for producing flexographic printing plate, flexographic printing method, and support

Abstract

A flexographic printing original plate in which at least a support (a) having a base material (f) and an adhesive layer (c) and a photosensitive resin composition layer (b) are laminated, wherein the adhesive layer (c) contains a reactive acrylic resin (c-1) having three or more (meth) acryloyl groups in the molecule.

Description

Flexographic printing original plate, flexographic printing plate manufacturing method, flexographic printing method, and support

[0001] The present invention relates to a flexographic printing plate precursor, a method for producing a flexographic printing plate, a flexographic printing method, and a support.

[0002] Flexographic printing plates generally have a structure in which a photosensitive resin composition layer is laminated on a support such as polyethylene terephthalate, etc. Also, a structure in which the support has a structure in which an adhesive layer is formed on a predetermined base material, thereby improving the adhesion between the support and the photosensitive resin composition layer, is known.

[0003] Flexographic printing is an example of relief printing, and is a printing technique in which ink is supplied to the raised surfaces of a textured resin plate using an ink supply roll or the like, and then the resin plate is brought into contact with a substrate to be printed, causing the ink on the raised surfaces to be transferred to the substrate. When a water-based ink is used as the ink, the water-based ink adhering to the plate surface is often wiped off with water or the like after printing, and the plate is then used for repeated printing, so long-term quality stability is required of flexographic printing plates.

[0004] However, since flexographic printing plates are required to have high conformability to uneven printing substrates, the photosensitive resin composition layer constituting the flexographic printing plate generally contains a plasticizer and is designed to be a soft material. Therefore, in flexographic printing plates that have been proposed so far, the plasticizer component in the photosensitive resin composition layer tends to bleed out, and the adhesive strength with the support tends to decrease over time, leaving room for improvement in terms of long-term quality stability (see, for example, Patent Document 1).

[0005] In view of the problems described above, a technology has been proposed for a flexographic printing plate in which a primer layer, a floor layer, and a photosensitive resin composition layer are sequentially laminated on a substrate, wherein the primer layer contains a compound having an isocyanate group and a polymer having a functional group that reacts with an isocyanate group, and the floor layer contains a water-insoluble elastomer having a functional group that reacts with an isocyanate group, and a covalent bond is formed at the interface between the primer layer and the floor layer by reaction of the isocyanate group, thereby suppressing a decrease in the interlayer adhesive strength of the primer layer / floor layer over time (see, for example, Patent Document 2).

[0006] Furthermore, an adhesive layer between a substrate and a photosensitive resin composition layer constituting a conventionally known flexographic printing plate generally contains an elastomer component, similar to the photosensitive resin composition layer, and the elastomer components of the adhesive layer and the photosensitive resin composition layer mutually diffuse at the adhesive interface between them, thereby exhibiting high adhesive strength (see, for example, Patent Document 3).

[0007] JP 10-148931 A JP 2023-139417 A Japanese Patent No. 4536531 A

[0008] However, the technology disclosed in Patent Document 2 has the problem that under conditions of high temperature and high humidity, such as a temperature of 40°C and a relative humidity of about 80% RH, which accelerates the bleeding out of the plasticizer component, the decrease in the interlayer adhesive strength can only be suppressed for about one week, and there is room for improvement in terms of long-term quality stability.

[0009] In addition, the technology disclosed in Patent Document 3 uses an organic solvent to dissolve the elastomer component when preparing the adhesive that constitutes the adhesive layer, and in the incineration treatment of organic solvent waste recovered in the drying step when the adhesive is applied to a substrate, CO ２ This causes a lot of waste and places a heavy burden on the environment.

[0010] In view of the problems of the conventional techniques, the present invention aims to provide a flexographic printing plate precursor from which a flexographic printing plate can be obtained that can suppress a decrease in adhesive strength between a support and a photosensitive resin composition layer for one month or more even under aging conditions in a high-temperature and high-humidity environment, for example, at a temperature of 40°C and a relative humidity of about 80% RH, and a support in which an adhesive coating liquid does not contain an organic solvent in a coating step for providing an adhesive layer on a base material constituting the support, thereby contributing to a reduction in environmental load.

[0011] As a result of intensive research conducted by the present inventors to solve the above-mentioned problems of the conventional art, the present inventors have found that in a flexographic printing original plate comprising a substrate and a support having an adhesive layer, and further a photosensitive resin composition layer laminated on the support, the above-mentioned problems of the conventional art can be solved by specifying that the adhesive layer contains an acrylic resin having a predetermined structure, and have thereby completed the present invention. That is, the present invention is as follows.

[0012] [1] A flexographic printing original plate comprising at least a support (a) having a substrate (f) and an adhesive layer (c), and a photosensitive resin composition layer (b) laminated together, wherein the adhesive layer (c) contains a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule. [2] A flexographic printing original plate comprising at least a support (a) having a substrate (f) and an adhesive layer (c), and a photosensitive resin composition layer (b) laminated together, wherein the adhesive layer (c) contains 3% by mass or more and 30% by mass or less of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule, and the flexographic printing original plate according to [1] above satisfies the following <Condition (1)>. <Condition (1)> 600 mJ / cm from the support (a) side. ２ , 8000 mJ / cm from the photosensitive resin composition layer (b) side ２

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[360] [ [6] A method for producing a flexographic printing plate using the flexographic printing precursor according to any one of [1] to [5] above, comprising: a first step of irradiating ultraviolet light from the support (a) side; a second step of placing a negative film on the photosensitive resin composition layer (b) or laser ablating an infrared ablation layer (d) provided on the photosensitive resin composition layer (b) to produce a negative pattern; a third step of irradiating the photosensitive resin composition layer (b) with ultraviolet light through the negative film or using the infrared ablation layer (d) on which the negative pattern has been drawn as a mask to perform pattern exposure; and a fourth step of removing unexposed areas of the photosensitive resin composition layer (b). [7] A flexographic printing method comprising: producing a flexographic printing plate by the method for producing a flexographic printing plate according to [6] above; and comprising: an ink applying step of applying ink to raised portions of the flexographic printing plate; and a transfer step of transferring the ink to a substrate. [8] A support (a) for a flexographic printing plate precursor having a substrate (f) and an adhesive layer (c), wherein the adhesive layer (c) contains a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule.[9] The support (a) according to [8], wherein the adhesive layer (c) contains 3% by mass or more and 30% by mass or less of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule.

[10] The support (a) according to [8], wherein the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule has a double bond equivalent of 1,500 or more and 5,000 or less.

[11] The support (a) according to [8], wherein the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule has a weight average molecular weight (Mw) of 14,000 or more and 60,000 or less.

[12] The support (a) according to [8], wherein the adhesive layer (c) contains a bifunctional or higher functional (meth)acrylate compound having one or more aromatic rings and / or one or more hydroxyl groups in the molecule.

[0013] According to the present invention, it is possible to provide a flexographic printing plate precursor that can produce a flexographic printing plate in which a decrease in adhesive strength between the support and the photosensitive resin composition layer is suppressed over a long period of time, such as one month or more, even under aging conditions in a high-temperature, high-humidity environment in which bleeding out of the plasticizer component in the photosensitive resin composition layer is promoted.Furthermore, according to the present invention, it is possible to provide a support for a flexographic printing plate precursor that does not use an organic solvent in the stage of coating the adhesive layer onto the substrate, thereby contributing to reducing the environmental load.

[0014] 1 is a schematic cross-sectional view of a flexographic printing plate precursor of the present embodiment; FIG. 2 is a schematic view showing a method for manufacturing a flexographic printing plate using the flexographic printing plate precursor of the present embodiment; FIG. 3 is a shape image obtained by force curve measurement by AFM in Example A1.

[0015] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the following present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out in various modified forms within the scope of its gist.

[0016] [Flexographic Printing Original Plate] The flexographic printing original plate of this embodiment is a flexographic printing original plate comprising at least a support (a) having a substrate (f) and an adhesive layer (c), and a photosensitive resin composition layer (b) laminated together. In the flexographic printing original plate of this embodiment, the adhesive layer (c) contains a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule.

[0017] According to the above-described configuration, even under aging conditions in a high-temperature and high-humidity environment at a temperature of 40°C and a relative humidity of about 80% RH, it is possible to suppress a decrease in the adhesive strength between the support (a) and the photosensitive resin composition layer (b) of the flexographic printing plate for one month or more.

[0018] In the flexographic printing plate precursor of this embodiment, the adhesive layer (c) preferably contains 3% by mass to 30% by mass of a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule, and preferably satisfies the following <Condition (1)>: <Condition (1)> 600 mJ / cm from the support (a) side ２ , 8000 mJ / cm from the photosensitive resin composition layer (b) side ２ When a cross section of the cured product obtained by irradiating the adhesive layer with ultraviolet light is measured by AFM (Atomic Force Microscopy, hereinafter referred to as AFM) for a force curve, the amount of deformation of the adhesive layer (c) is 20 nm or less.

[0019] FIG. 1 shows a schematic cross-sectional view of a flexographic printing plate precursor 1 of this embodiment. The flexographic printing plate precursor of this embodiment includes a support (a) having a substrate (f) and an adhesive layer (c), and a photosensitive resin composition layer (b) on which a relief pattern of the flexographic printing plate is formed, with the adhesive layer (c) between the substrate (f) and the photosensitive resin composition layer (b). The flexographic printing plate precursor 1 of this embodiment may also include a solvent-soluble, thin, flexible protective layer (see, for example, JP-B-5-13305) that functions to improve contact with a predetermined negative film, as needed. The flexographic printing plate precursor of this embodiment shown in FIG. 1 may also include an infrared ablation layer (d) on the photosensitive resin composition layer (b) side, which functions as a mask when the relief pattern is formed. The flexographic printing plate precursor of this embodiment may further include other layers between the respective layers, as needed. The flexographic printing plate precursor of this embodiment will now be described.

[0020] (Substrate (f) used in substrate (a)) The substrate (a) constituting the flexographic printing original plate of this embodiment has a substrate (f) and an adhesive layer (c) described below. Examples of the substrate (f) include, but are not limited to, polyester films, polyamide films, polyacrylonitrile films, polyvinyl chloride films, etc. Polyester films are preferred as the substrate (f). Examples of the polyester films used for the substrate (f) include, but are not limited to, polyethylene terephthalate films, polybutylene terephthalate films, polyethylene naphthalate films, etc.

[0021] Furthermore, in order to obtain even higher adhesive strength between the adhesive layer (c) described below and the polyester film substrate (f), it is preferable to provide at least one undercoat layer. The undercoat layer is preferably about 0.001 to 1 μm thick. Polyester films having an undercoat layer are preferably produced in an in-line process, in which the undercoat layer components are applied during the biaxially stretched film production process. The presence or absence of the undercoat layer can be determined by known techniques such as infrared absorption spectroscopy and electron spectroscopy. The presence or absence of an undercoat layer can also be determined by irradiating the substrate (f) with an ion beam to decompose the surface of the substrate (f) and analyzing the decomposition product.

[0022] Films having the subbing layer are commercially available and can be used as the substrate (f) in the flexographic printing plate precursor of this embodiment. Examples of polyester films having an undercoat layer include, but are not limited to, the "Lumirror U34" (trademark) series manufactured by Toray Industries, Inc., the "Lumirror U40" (trademark) series manufactured by Toray Industries, Inc., the "Lumirror U48" (trademark) series manufactured by Toyobo Co., Ltd., the "Cosmoshine A4000" (trademark) series manufactured by Nan Ya Plastics Corporation, the "CD18H5" (trademark) manufactured by Nan Ya Plastics Corporation, the "CD18T7" (trademark) manufactured by Nan Ya Plastics Corporation, the "CP18H5" (trademark) manufactured by Nan Ya Plastics Corporation, the "CP18T7" (trademark) manufactured by Nan Ya Plastics Corporation, the "Tetoron HPE, SG2" (trademark) manufactured by Teijin Limited, and the "Melinex 700" (trademark) series manufactured by DuPont.

[0023] From the viewpoint of obtaining better adhesion, the main component of the undercoat layer is preferably a (meth)acrylate polymer or copolymer thereof, or a compound having a urethane bond. Examples of (meth)acrylate polymers or copolymers thereof include, but are not limited to, polymers and copolymers of methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, glycidyl (meth)acrylate, and the like. Furthermore, the above polymers and copolymers can also be copolymerized with (meth)acrylic acid, styrene, acrylonitrile, vinyl chloride, and the like, as needed.

[0024] Furthermore, the compound having a urethane bond is preferably a compound having a urethane bond obtained from an isocyanate compound having one or more aromatic rings. Examples of such compounds include the reaction products of the following compounds having active hydrogen with compounds having an isocyanate group. Examples of compounds having active hydrogen include diols such as ethylene glycol, 1,4-butanediol, neopentyl glycol, and polyether diols formed from polyethers thereof. Furthermore, polyester compounds can also have active hydrogen and can therefore be used as components having active hydrogen capable of forming urethane bonds. Examples of raw materials for such polyester compounds include dicarboxylic acid components such as terephthalic acid and isophthalic acid, and alcohol components such as ethylene glycol, 1,4-butanediol, and polyether polyol compounds thereof. Condensates of these dicarboxylic acid components and alcohol components can be used as the polyester compound. Furthermore, the compound having an isocyanate group may be a polyisocyanate, and examples of such polyisocyanates include aromatic isocyanates such as toluene diisocyanate and 4,4-diphenylenemethane diisocyanate.

[0025] The thickness of the substrate (f) is not particularly limited, but is preferably 50 to 300 μm from the viewpoints of handling and strength.

[0026] (Photosensitive Resin Composition Layer (b)) The support (a) constituting the flexographic printing original plate of this embodiment has the above-mentioned substrate (f) and the adhesive layer (c) described below, and the flexographic printing original plate of this embodiment has the adhesive layer (c) between the substrate (f) and the photosensitive resin composition layer (b). The material of the photosensitive resin composition layer (b) is not particularly limited, but may contain, for example, a thermoplastic elastomer (b-1), and preferably may further contain an ethylenically unsaturated compound (b-2), a photopolymerization initiator (b-3), and a liquid diene. Furthermore, the photosensitive resin composition layer (b) may further contain auxiliary additive components as necessary. Each component will be described in detail below.

[0027] <Thermoplastic elastomer (b-1)> The thermoplastic elastomer (b-1) is not limited to the following, but examples thereof include a copolymer having a structural unit derived from a monovinyl-substituted aromatic hydrocarbon and a structural unit derived from a conjugated diene. The thermoplastic elastomer (b-1) may further have a structural unit derived from another monomer. Use of such a thermoplastic elastomer tends to further improve the printing durability of a flexographic printing plate produced using the flexographic printing plate precursor of this embodiment.

[0028] The thermoplastic elastomer (b-1) may be a random copolymer or a block copolymer, but is preferably a block copolymer having a polymer block of a monovinyl-substituted aromatic hydrocarbon and a polymer block of a conjugated diene. Use of such a thermoplastic elastomer tends to further improve the printing durability of a flexographic printing plate produced using the flexographic printing plate precursor of this embodiment.

[0029] Examples of the monovinyl-substituted aromatic hydrocarbon constituting the thermoplastic elastomer (b-1) include, but are not limited to, styrene, t-butylstyrene, 1,1-diphenylethylene, N,N-dimethyl-p-aminoethylstyrene, N,N-diethyl-p-aminoethylstyrene, vinylpyridine, p-methylstyrene, p-methoxystyrene, tertiary butylstyrene, α-methylstyrene, and 1,1-diphenylethylene. These may be used alone or in combination of two or more. Among these, styrene is preferred as the monovinyl-substituted aromatic hydrocarbon from the viewpoint of enabling the photosensitive resin composition layer (b) to be smoothly molded at a relatively low temperature.

[0030] Conjugated dienes constituting the thermoplastic elastomer (b-1) include, but are not limited to, butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, and chloroprene. These may be used alone or in combination of two or more. Of these, butadiene is preferred as the conjugated diene from the viewpoint of the printing durability of a flexographic printing plate produced using the flexographic printing precursor of this embodiment.

[0031] From the viewpoint of ensuring that the viscosity of the photosensitive resin composition at room temperature is appropriate, the number average molecular weight (Mn) of the thermoplastic elastomer (b-1) is preferably from 20,000 to 300,000, and more preferably from 50,000 to 200,000. The number average molecular weight of the thermoplastic elastomer (b-1) can be measured by gel permeation chromatography (GPC) and is expressed in terms of polystyrene equivalent molecular weight.

[0032] When the thermoplastic elastomer (b-1) is a block copolymer having a polymer block made of a monovinyl-substituted aromatic hydrocarbon and a polymer block made of a conjugated diene, the thermoplastic elastomer (b-1) includes, for example, a linear block copolymer represented by the following general formula group (I) and / or a linear block copolymer or a radial block copolymer represented by the following general formula group (II): General formula group (I): (A-B) ｎ , A-(B-A) ｎ , A-(B-A) ｎ -B, B- (A-B) ｎ General formula group (II): [(AB) ｋ ] ｍ -X, [(A-B) ｋ -A] ｍ -X, [(B-A) ｋ ] ｍ -X, [(B-A) ｋ -B] ｍ -X In the general formula groups (I) and (II), A represents a polymer block composed of a monovinyl-substituted aromatic hydrocarbon. B represents a polymer block composed of a conjugated diene. X represents a residue of a coupling agent selected from the group consisting of silicon tetrachloride, tin tetrachloride, epoxidized soybean oil, polyhalogenated hydrocarbon compounds, carboxylic acid ester compounds, polyvinyl compounds, bisphenol-type epoxy compounds, alkoxysilane compounds, halogenated silane compounds, and ester-based compounds, or a residue of a polymerization initiator such as a polyfunctional organolithium compound. In the general formula groups (I) and (II), n, k, and m represent integers of 1 or more, for example, 1 to 5.

[0033] The content of conjugated dienes and monovinyl-substituted aromatic hydrocarbons in the thermoplastic elastomer (b-1) was measured using a nuclear magnetic resonance spectrometer ( １ H-NMR). １Measurements can be performed using a JNM-LA400 (trade name, manufactured by JEOL) as the H-NMR measurement instrument, deuterated chloroform as the solvent, a sample concentration of 50 mg / mL, an observation frequency of 400 MHz, TMS (tetramethylsilane) as the chemical shift standard, a pulse delay of 2.904 seconds, 64 scans, a pulse width of 45°C, and a measurement temperature of 25°C. In the thermoplastic elastomer (b-1), from the viewpoint of the printing durability and surface smoothness of the flexographic printing plate, the copolymerization ratio (mass ratio) of the monovinyl-substituted aromatic hydrocarbon to the conjugated diene is preferably monovinyl-substituted aromatic hydrocarbon / conjugated diene = 10 / 90 to 90 / 10, more preferably 10 / 90 to 70 / 30, and even more preferably 10 / 90 to 50 / 50. In the above ratio (mass ratio), when the proportion of the monovinyl-substituted aromatic hydrocarbon is 10 or more, sufficient hardness can be obtained in the photosensitive resin composition layer (b), and appropriate printing can be performed with normal printing pressure. In addition, when the proportion of the monovinyl-substituted aromatic hydrocarbon is 90 or less in the above ratio (mass ratio), appropriate hardness can be obtained in the photosensitive resin composition layer (b), and the ink can be sufficiently transferred to the printing object in the printing process.

[0034] If necessary, other functional groups may be introduced into the thermoplastic elastomer (b-1), or the thermoplastic elastomer (b-1) may be chemically modified by hydrogenation or the like, or may be copolymerized with other components.

[0035] From the viewpoint of improving ink entanglement in a flexographic printing plate produced using the flexographic printing precursor of this embodiment, the content of the thermoplastic elastomer (b-1) in the photosensitive resin composition layer (b) is preferably 40% by mass or more, more preferably 40% by mass or more and 80% by mass or less, even more preferably 45% by mass or more and 80% by mass or less, and even more preferably 45% by mass or more and 75% by mass or less, when the total amount of the photosensitive resin composition layer (b) is taken as 100% by mass.

[0036] <Ethylenically Unsaturated Compound (b-2)> As described above, the photosensitive resin composition layer (b) preferably contains an ethylenically unsaturated compound (b-2). The ethylenically unsaturated compound (b-2) is a compound having a radically polymerizable unsaturated double bond. Examples of such an ethylenically unsaturated compound (b-2) include, but are not limited to, olefins such as ethylene, propylene, vinyltoluene, styrene, and divinylbenzene; acetylenes; (meth)acrylic acid and / or its derivatives; haloolefins; unsaturated nitriles such as acrylonitrile; unsaturated amides and derivatives thereof such as acrylamide and methacrylamide; unsaturated dicarboxylic acids and derivatives thereof such as maleic anhydride, maleic acid, and fumaric acid; vinyl acetates; N-vinylpyrrolidone; N-vinylcarbazole; and N-substituted maleimide compounds. Among these, (meth)acrylic acid and / or its derivatives are preferred from the viewpoints of UV curability and the printing durability of the photosensitive resin composition layer (b) after curing. Examples of the derivatives include, but are not limited to, alicyclic compounds having a cycloalkyl group, a bicycloalkyl group, a cycloalkenyl group, a bicycloalkenyl group, or the like; aromatic compounds having a benzyl group, a phenyl group, a phenoxy group, or a naphthalene skeleton, an anthracene skeleton, a biphenyl skeleton, a phenanthrene skeleton, a fluorene skeleton, or the like; compounds having an alkyl group, a halogenated alkyl group, an alkoxyalkyl group, a hydroxyalkyl group, an aminoalkyl group, a glycidyl group, or the like; ester compounds with polyhydric alcohols such as alkylene glycol, polyoxyalkylene glycol, polyalkylene glycol, and trimethylolpropane; and compounds having a polysiloxane structure such as polydimethylsiloxane and polydiethylsiloxane.

[0037] The ethylenically unsaturated compound (b-2) may also be a heteroaromatic compound containing elements such as nitrogen and sulfur.

[0038] Examples of the (meth)acrylic acid and / or derivatives thereof include, but are not limited to, diacrylates and dimethacrylates of alkanediols such as hexanediol and nonanediol; diacrylates and dimethacrylates of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, and butylene glycol; trimethylolpropane tri(meth)acrylate; dimethyloltricyclodecane di(meth)acrylate; isobornyl(meth)acrylate; phenoxypolyethylene glycol (meth)acrylate; pentaerythritol tetra(meth)acrylate, etc. These may be used alone or in combination of two or more.

[0039] From the viewpoint of the mechanical strength of a flexographic printing plate produced using the flexographic printing precursor of this embodiment, it is preferable to use at least one type of (meth)acrylate as the ethylenically unsaturated compound (b-2), and it is more preferable to use at least one type of bifunctional (meth)acrylate.

[0040] The number average molecular weight (Mn) of the ethylenically unsaturated compound (b-2) is preferably 100 or more from the viewpoint of improving the non-volatility of the ethylenically unsaturated compound (b-2) during production and storage of the flexographic printing precursor of this embodiment, and from the viewpoint of compatibility with other components, it is preferably less than 1,000, and more preferably from 200 to 800. The content of the ethylenically unsaturated compound (b-2) in the photosensitive resin composition layer (b) is preferably from 2 to 30% by mass, more preferably from 2 to 25% by mass, and even more preferably from 2 to 20% by mass, when the total amount of the photosensitive resin composition layer (b) is taken as 100% by mass, from the viewpoint of improving ink entanglement in a flexographic printing plate produced using the flexographic printing precursor of this embodiment.

[0041] <Photopolymerization initiator (b-3)> The photosensitive resin composition layer (b) preferably contains a photopolymerization initiator (b-3). The photopolymerization initiator (b-3) is a compound that absorbs light energy and generates radicals, and examples of the photopolymerization initiator (b-3) include a degradable photopolymerization initiator, a hydrogen abstraction photopolymerization initiator, and a compound having a moiety that functions as a hydrogen abstraction photopolymerization initiator and a moiety that functions as a degradable photopolymerization initiator in the same molecule.

[0042] Examples of such photopolymerization initiator (b-3) include, but are not limited to, benzophenone, 4,4-bis(diethylamino)benzophenone, 3,3',4,4'-benzophenonetetracarboxylic anhydride, 3,3',4,4'-tetramethoxybenzophenone, and other benzophenones; anthraquinones, such as t-butylanthraquinone and 2-ethylanthraquinone; thioxanthones, such as 2,4-diethylthioxanthone, isopropylthioxanthone, and 2,4-dichlorothioxanthone; Michler's ketone; diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-methyl-1-( acetophenones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, trichloroacetophenone, etc.; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc.; acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, etc.; methylbenzoyl formate; 1,7-bisacridinylheptane; 9-phenylacridine; azo compounds such as azobisisobutyronitrile, diazonium compounds, and tetrazene compounds. These may be used alone or in combination of two or more. Among these, from the viewpoint of printing durability of a flexographic printing plate produced using the flexographic printing precursor of this embodiment, compounds having a carbonyl group are preferred as the photopolymerization initiator (b-3), and aromatic carbonyl compounds such as benzophenones and thioxanthones are more preferred.

[0043] From the viewpoint of improving ink entanglement in a flexographic printing plate produced using the flexographic printing precursor of this embodiment, the content of the photopolymerization initiator (b-3) in the photosensitive resin composition layer (b) is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 0.5% by mass or more and 5% by mass or less, when the total amount of the photosensitive resin composition layer (b) is taken as 100% by mass.

[0044] <Liquid Diene> The photosensitive resin composition layer (b) preferably contains a liquid diene. A liquid diene is a compound having a liquid carbon-carbon double bond. Here, in this specification, the term "liquid" in "liquid diene" refers to a property of being easily fluid and deformable and being able to solidify into the deformed shape upon cooling. A liquid diene has elastomeric properties, i.e., when an external force is applied, it deforms instantaneously in response to the external force and recovers its original shape in a short time when the external force is removed. A liquid diene can be distinguished from the thermoplastic elastomer (b-1) and the ethylenically unsaturated compound (b-2) in that it is liquid at room temperature and has elastomeric properties. The liquid diene is a copolymer containing 50% or more by mass of a diene component.

[0045] Examples of liquid dienes include, but are not limited to, liquid polybutadiene, liquid polyisoprene, modified liquid polybutadiene, modified liquid polyisoprene, liquid acrylonitrile-butadiene copolymer, and liquid styrene-butadiene copolymer. Among these, liquid polybutadiene is preferred from the viewpoint of the mechanical properties of a flexographic printing plate produced using the flexographic printing plate precursor of this embodiment.

[0046] Furthermore, the 1,2-vinyl bond content of the liquid diene, preferably liquid polybutadiene, is preferably 1% to 80% inclusive, more preferably 5% to 70% inclusive, and even more preferably 5% to 65% inclusive, from the viewpoint of ensuring appropriate hardness of the flexographic printing plate precursor of this embodiment and the flexographic printing plate produced using the same. Here, the "1,2-vinyl bond content" refers to the proportion of conjugated diene monomers incorporated via 1,2-bonds among those incorporated via 1,2-bonds, 3,4-bonds, and 1,4-bonds. The 1,2-vinyl bond content can be determined from the peak ratio in the proton NMR (magnetic resonance spectrum) of the liquid polybutadiene. 1,2-polybutadiene, which is a liquid polybutadiene having 1,2-vinyl bonds, has a vinyl double bond in a side chain, which makes it highly reactive in radical polymerization and is therefore preferred from the viewpoint of increasing the hardness of the photosensitive resin composition layer (b).

[0047] Furthermore, liquid polybutadiene is typically a mixture of 1,2-polybutadiene having a 1,2-vinyl bond and 1,4-polybutadiene having a 1,4-vinyl bond. In order to improve the flexibility of the flexographic printing plate precursor of this embodiment and the flexographic printing plate produced using the same, it is effective to include 1,4-polybutadiene in the liquid diene. 1,4-Polybutadienes include cis-type 1,4-polybutadienes and trans-type 1,4-polybutadienes. Both cis-type and trans-type 1,4-polybutadienes have a vinyl group, which is a double bond, present inside, resulting in low reactivity in radical polymerization. By including 1,4-polybutadiene, it is possible to produce a flexible photosensitive resin composition.

[0048] When a mixture of liquid polybutadienes having different 1,2-vinyl bond contents is used, the average value thereof is taken as the 1,2-vinyl bond content of the liquid polybutadiene described above. From the viewpoint of easily adjusting the reactivity of the photosensitive resin composition layer (b), it is preferable to adjust the overall 1,2-vinyl bond content by mixing a liquid polybutadiene having a 1,2-vinyl bond content of 10% or less with a liquid polybutadiene having a 1,2-vinyl bond content of 80% or more. Furthermore, from the same viewpoint as above, it is more preferable to adjust the overall 1,2-vinyl bond content by mixing a liquid polybutadiene having a 1,2-vinyl bond content of 5% or less with a liquid polybutadiene having a 1,2-vinyl bond content of 80% or more.

[0049] Furthermore, the number average molecular weight of the liquid diene is not particularly limited as long as it is liquid at room temperature, i.e., at a temperature of about 20°C. However, from the viewpoint of printing durability and handling of a flexographic printing plate produced using the flexographic printing precursor of this embodiment, it is preferably 500 or more and 60,000 or less, more preferably 500 or more and 50,000 or less, and even more preferably 800 or more and 50,000 or less.

[0050] From the viewpoint of improving ink intertwining in a flexographic printing plate produced using the flexographic printing precursor of this embodiment, the content of the liquid diene in the photosensitive resin composition layer (b) is preferably 10% by mass or more and 40% by mass or less, more preferably 15% by mass or more and 40% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less, when the total amount of the photosensitive resin composition layer (b) is taken as 100% by mass.

[0051] <Auxiliary Additive Components> Examples of auxiliary additive components include, but are not limited to, polymer particles, polar group-containing polymers, plasticizers other than liquid dienes, thermal polymerization inhibitors, antioxidants, ultraviolet absorbers, dyes and pigments.

[0052] The polymer particles are polymer particles in which a monomer is internally crosslinked. Examples of such polymer particles include, but are not limited to, those obtained by preparing a water-dispersible latex by dispersing polymer particles as a dispersoid in water by emulsion polymerization, and then removing water from the obtained water-dispersible latex.

[0053] The monomer constituting the polymer particles may be any monomer having a polymerizable double bond, and includes, but is not limited to, monobasic acid monomers, polybasic acid monomers, conjugated dienes, aromatic vinyl compounds, (meth)acrylic acid esters, monomers having a hydroxyl group, unsaturated dibasic acid alkyl esters, maleic anhydride, vinyl cyanide compounds, (meth)acrylamide and its derivatives, vinyl esters, vinyl ethers, vinyl halides, basic monomers having an amino group, vinylpyridine, olefins, silicon-containing α,β-ethylenically unsaturated monomers, allyl compounds, etc. The monomer constituting the polymer particles may also contain a reactive emulsifier used in emulsion polymerization, which will be described later.

[0054] Examples of monobasic acid monomers include, but are not limited to, monomers having a carboxyl group such as acrylic acid, methacrylic acid, crotonic acid, vinylbenzoic acid, and cinnamic acid; and monomers having a sulfonic acid group such as styrenesulfonic acid.

[0055] The content of the monobasic acid monomer is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, even more preferably 3 to 15% by mass, and still more preferably 5 to 10% by mass, based on the total amount of the polymer particles.

[0056] Examples of polybasic acid monomers include, but are not limited to, monomers having two or more carboxyl groups such as itaconic acid, fumaric acid, maleic acid, citraconic acid, and muconic acid; monomers having an acid anhydride group; and monomers having a polybasic acid group such as a phosphate group.

[0057] Examples of conjugated dienes include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-ethyl-1,3-butadiene, 2-methyl-1,3-butadiene, 1,3-pentadiene, chloroprene, 2-chloro-1,3-butadiene, and cyclopentadiene.

[0058] The content of the conjugated diene is preferably 30 to 90% by mass, more preferably 40 to 85% by mass, and even more preferably 50 to 80% by mass, based on the total amount of the polymer particles.

[0059] Examples of aromatic vinyl compounds include, but are not limited to, styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, ethylstyrene, vinyltoluene, vinylxylene, bromostyrene, vinylbenzyl chloride, p-t-butylstyrene, chlorostyrene, alkylstyrene, divinylbenzene, and trivinylbenzene.

[0060] The content of the aromatic vinyl compound is preferably 2.5 to 40% by mass, more preferably 5 to 35% by mass, and even more preferably 7.5 to 30% by mass, based on the total amount of the polymer particles.

[0061] Examples of (meth)acrylic acid esters include, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like. p) acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, glycidyl (meth)acrylate, ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexane Diol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, allyl (meth)acrylate, bis(4-acryloxypolyethoxyphenyl)propane , methoxypolyethylene glycol (meth)acrylate, β-(meth)acryloyloxyethyl hydrogen phthalate, β-(meth)acryloyloxyethyl hydrogen succinate, 3-chloro-2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, 2-hydroxy-1,3-di(meth)acryloxypropane, 2,2-bis[4-((meth)acryloxyethoxy)phenyl]propane, 2,Examples include 2-bis[4-((meth)acryloxy-diethoxy)phenyl]propane, 2,2-bis[4-((meth)acryloxy-polyethoxy)phenyl]propane, and isobornyl(meth)acrylate.

[0062] The content of the (meth)acrylic acid ester is preferably 10 to 40% by mass, more preferably 15 to 35% by mass, and even more preferably 20 to 30% by mass, based on the total amount of the polymer particles.

[0063] Examples of the monomer having a hydroxyl group include, but are not limited to, ethylenic monocarboxylic acid alkyl ester monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 1-hydroxypropyl acrylate, 1-hydroxypropyl methacrylate, and hydroxycyclohexyl (meth)acrylate.

[0064] Examples of unsaturated dibasic acid alkyl esters include, but are not limited to, crotonic acid alkyl esters, itaconic acid alkyl esters, fumaric acid alkyl esters, and maleic acid alkyl esters.

[0065] Examples of vinyl cyanide compounds include, but are not limited to, acrylonitrile and methacrylonitrile.

[0066] Examples of (meth)acrylamide and derivatives thereof include, but are not limited to, (meth)acrylamide, N-methylol(meth)acrylamide, and N-alkoxy(meth)acrylamide.

[0067] Examples of vinyl esters include, but are not limited to, vinyl acetate, vinyl butyrate, vinyl stearate, vinyl laurate, vinyl myristate, vinyl propionate, vinyl versatate, and the like.

[0068] Examples of vinyl ethers include, but are not limited to, methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, amyl vinyl ether, and hexyl vinyl ether.

[0069] Examples of vinyl halides include, but are not limited to, vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, and vinylidene fluoride.

[0070] Examples of basic monomers having an amino group include, but are not limited to, aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and diethylaminoethyl (meth)acrylate.

[0071] The olefin may be, but is not limited to, ethylene.

[0072] Examples of the silicon-containing α,β-ethylenically unsaturated monomer include, but are not limited to, vinyltrichlorosilane, vinyltriethoxysilane, and the like.

[0073] The allyl compound is not limited to the following, but examples thereof include allyl esters and diallyl phthalates.

[0074] In addition, a monomer having three or more double bonds such as triallyl isocyanurate can also be used.

[0075] These monomers may be used alone or in combination of two or more. Among them, it is preferable to use a monomer having an acidic group, such as a monobasic acid monomer or a polybasic acid monomer (hereinafter simply referred to as an "acidic monomer"), and a monomer having a hydrophobic group, such as a conjugated diene, an aromatic vinyl compound, or a (meth)acrylic acid ester (hereinafter simply referred to as a "hydrophobic monomer"). The conjugated diene, aromatic vinyl compound, or (meth)acrylic acid ester, which corresponds to the hydrophobic monomer, has a hydrocarbon group, and those having a hydrophilic group such as a hydroxyl group are excluded from the hydrophobic monomer, even if they are (meth)acrylic acid esters or the like.

[0076] The content of the acidic monomer is preferably 1 to 30% by mass, more preferably 2 to 20% by mass, even more preferably 3 to 15% by mass, and even more preferably 5 to 10% by mass, relative to the total amount of the polymer particles. By making the content of the acidic monomer 1% by mass or more, adhesion to the substrate tends to be improved. Furthermore, by making the content 30% by mass or less, an increase in the moisture absorption amount of the photosensitive resin composition and an increase in the swelling amount of the ink can be prevented, and a deterioration in processability during mixing of the photosensitive resin composition can be prevented.

[0077] The content of the monomer having a hydrophobic group is preferably 70 to 99% by mass, more preferably 80 to 98% by mass, even more preferably 85 to 97% by mass, and still more preferably 90 to 95% by mass. When the polymer particles have such a composition, the rubber elasticity of the photosensitive resin composition tends to be further improved.

[0078] Examples of the polymer constituting the polymer particles include, but are not limited to, polymers having a butadiene skeleton such as polybutadiene, acrylonitrile-butadiene copolymer, styrene-butadiene copolymer, and (meth)acrylate-butadiene copolymer; polymers having an isoprene skeleton such as polyisoprene and polychloroprene; polymers obtained by further polymerizing a monomer having a carboxyl group and / or a hydroxyl group to the polymer having a butadiene skeleton or an isoprene skeleton; polymers obtained by further polymerizing a (meth)acrylic acid ester to the polymer having a butadiene skeleton or an isoprene skeleton; polymers obtained by further polymerizing a (meth)acrylic acid ester and a monomer having a carboxyl group and / or a hydroxyl group to the polymer having a butadiene skeleton or an isoprene skeleton; polyurethane, vinylpyridine polymer, butyl polymer, thiokol polymer, acrylate polymer, and natural rubber.

[0079] Here, the monomer having a carboxyl group means the above-mentioned monobasic acid monomer and / or polybasic acid monomer.

[0080] Among these, preferred are polymers having a butadiene skeleton, polymers having an isoprene skeleton, and polymers obtained by further polymerizing the above-mentioned polymers having a butadiene skeleton or an isoprene skeleton with a (meth)acrylic acid ester and / or a monomer having a carboxyl group and / or a hydroxyl group, and more preferred are polymers obtained by further polymerizing the above-mentioned polymers having a butadiene skeleton with a (meth)acrylic acid ester and / or a monomer having a carboxyl group and / or a hydroxyl group. The polymer particles may be used alone or in combination of two or more types.

[0081] The average particle size of the polymer particles is preferably 500 nm or less, more preferably 100 nm or less. When the average particle size is 500 nm or less, the aqueous developability of the flexographic printing plate precursor tends to be further improved.

[0082] The toluene gel fraction of the polymer particles is preferably 60% to 99%. When the toluene gel fraction is 60% or more, the resulting flexographic printing plate tends to have sufficient strength for practical use. When the toluene gel fraction is 99% or less, the polymer particles tend to be well mixed with the thermoplastic elastomer.

[0083] Here, the toluene gel fraction refers to a mass fraction (%) obtained by dropping an appropriate amount of a dispersion of about 30% by mass of polymer particles onto a Teflon (registered trademark) sheet, drying at 130°C for 30 minutes, taking 0.5 g of polymer particles, immersing this in 30 mL of toluene at 25°C, shaking it for 3 hours using a shaker, filtering it through a 320 SUS mesh, and drying the refractory part at 130°C for 1 hour, and then dividing the mass by 0.5 (g).

[0084] From the viewpoint of developability during production of a flexographic printing plate, the content of the polymer particles is preferably 10 to 70% by mass, more preferably 15 to 60% by mass, and even more preferably 20 to 50% by mass, when the total amount of the photosensitive resin composition is taken as 100% by mass.

[0085] Examples of polar group-containing polymers include, but are not limited to, copolymers having polar groups such as hydrophilic groups such as carboxyl groups, amino groups, hydroxyl groups, phosphoric acid groups, and sulfonic acid groups, and salts thereof. More specific examples include carboxyl group-containing acrylonitrile-butadiene rubber, carboxyl group-containing styrene-butadiene rubber, polymers of aliphatic conjugated dienes containing carboxyl groups, polymers of ethylenically unsaturated compounds having phosphoric acid groups or carboxyl groups, and sulfonic acid group-containing polyurethanes. These polar group-containing polymers may be used alone or in combination of two or more.

[0086] Examples of plasticizers other than liquid dienes include, but are not limited to, hydrocarbon oils such as naphthenic oil and paraffin oil; liquid diene-based conjugated diene rubbers such as liquid acrylonitrile-butadiene copolymers and liquid styrene-butadiene copolymers; polystyrenes having a number average molecular weight of 2000 or less; and ester-based plasticizers such as sebacate esters and phthalate esters. These plasticizers other than liquid dienes may have a hydroxyl group or a carboxyl group. Furthermore, these plasticizers other than liquid dienes may be provided with a photopolymerizable reactive group such as a (meth)acryloyl group. The plasticizers may be used alone or in combination of two or more.

[0087] As the thermal polymerization inhibitor and antioxidant, those commonly used in the fields of resin materials or rubber materials can be used. Specific examples include phenolic materials. Examples of such phenolic materials include, but are not limited to, vitamin E, tetrakis-(methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate)methane, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, and 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate. The thermal polymerization inhibitor and antioxidant may be used alone or in combination of two or more.

[0088] Examples of ultraviolet absorbers include, but are not limited to, known benzophenone-based compounds, salicylate-based compounds, acrylonitrile-based compounds, metal complex salt-based compounds, and hindered amine-based compounds. Furthermore, the dyes and pigments listed below may also be used as ultraviolet absorbers. Examples of such ultraviolet absorbers include, but are not limited to, 2-ethoxy-2'-ethyloxalic acid bisanilide and 2,2'-dihydroxy-4-methoxybenzophenone. Dyes and pigments are effective as coloring means for improving visibility. Examples of dyes include, but are not limited to, water-soluble basic dyes, acid dyes, direct dyes, etc., as well as water-insoluble sulfur dyes, oil-soluble dyes, disperse dyes, etc. Anthraquinone-based dyes, indigoid dyes, and azo-based dyes are particularly preferred, with azo-based oil-soluble dyes and the like being more preferred. Examples of pigments include, but are not limited to, natural pigments, synthetic inorganic pigments, synthetic organic pigments, etc. Examples of synthetic organic pigments include azo pigments, triphenylmethane pigments, quinoline pigments, anthraquinone pigments, and phthalocyanine pigments.

[0089] The total amount of the auxiliary additive components described above is preferably 0% by mass or more and 10% by mass or less, more preferably 0% by mass or more and 5% by mass or less, and even more preferably 0% by mass or more and 3% by mass or less, when the total amount of the photosensitive resin composition layer (b) is 100% by mass.

[0090] (Adhesive Layer (c)) In the flexographic printing original plate of this embodiment, from the viewpoint of suppressing a decrease in adhesive strength between the support (a) and the photosensitive resin composition (b) over time under high-temperature and high-humidity conditions, the adhesive layer (c) contains a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule.

[0091] In the flexographic printing plate precursor of this embodiment, from the viewpoint of achieving the above-mentioned effects, the content of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule in the adhesive layer (c) is preferably 3% by mass or more, more preferably 4% by mass or more, and even more preferably 5% by mass or more. Furthermore, in the flexographic printing plate precursor of this embodiment, from the viewpoint of obtaining high initial adhesive strength, the content of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule in the adhesive layer (c) is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0092] From the above viewpoints, in the flexographic printing plate precursor of this embodiment, the adhesive layer (c) preferably contains a reactive acrylic resin (c-1) having five or more (meth)acryloyl groups in the molecule, and more preferably contains a reactive acrylic resin (c-1) having six or more (meth)acryloyl groups in the molecule. In the flexographic printing plate precursor of this embodiment, from the viewpoint of achieving the above-mentioned effects, the content of the reactive acrylic resin (c-1) having five or more or six or more (meth)acryloyl groups in the molecule in the adhesive layer (c) is preferably 3% by mass or more, more preferably 4% by mass or more, and even more preferably 5% by mass or more. Furthermore, in the flexographic printing plate precursor of this embodiment, from the viewpoint of obtaining high initial adhesive strength, the content of the reactive acrylic resin (c-1) having five or more or six or more (meth)acryloyl groups in the adhesive layer (c) is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less.

[0093] Furthermore, in the flexographic printing plate precursor of this embodiment, from the viewpoint of achieving the above-mentioned effects, it is preferable to specify the physical properties of the adhesive layer (c) under predetermined conditions. The plasticizer component in the photosensitive resin composition layer (b) usually tends to accelerate bleed-out when stored for a long period of time under conditions of a temperature of 40°C and a relative humidity of about 80% RH. In the flexographic printing plate precursor of this embodiment, from the viewpoint of suppressing a decrease in the adhesive strength between the support (a) and the photosensitive resin composition layer (b) over a long period of time of one month or more even under the above-mentioned conditions, it is preferable to focus on the degree of curing of the adhesive layer (c) constituting the flexographic printing plate precursor after ultraviolet curing, and specify the deformation amount of the adhesive layer (c) after exposure to 20 nm or less in force curve measurement by AFM.

[0094] Generally, plasticizers penetrate between polymer molecules to weaken intermolecular forces, thereby lowering the glass transition temperature of the polymer and imparting flexibility to the polymer. Because flexographic printing plates are required to have high conformability to various printing substrates with different surface smoothness, the photosensitive resin composition layer (b) constituting the flexographic printing plate typically contains a plasticizer component. On the other hand, it is known that if the migration of the plasticizer component to the adhesive layer (c) is accelerated, in a peel test of the support (a) constituting the flexographic printing plate, cohesive failure tends to occur in the adhesive layer (c) or interfacial failure tends to occur at the interface with the photosensitive resin composition layer (b), resulting in a decrease in adhesive strength between the support (a) and the photosensitive resin composition layer (b). In consideration of the above-mentioned problems, in the flexographic printing plate precursor of this embodiment, the adhesive layer (c) of the flexographic printing plate has high hardness and a high crosslink density, and by specifying the deformation amount of the adhesive layer (c) after curing, the cohesive failure and interfacial failure of the adhesive layer (c) can be suppressed.

[0095] One method for measuring the hardness of the adhesive layer (c) is force curve measurement using an AFM. In the force curve measurement, the displacement of a measurement probe when a predetermined load is applied to the measurement probe is calculated. The displacement of the probe means the amount of deformation of the measurement sample that occurs when a predetermined load is applied. Note that the smaller the deformation, the higher the hardness of the measurement sample.

[0096] In the flexographic printing original plate of this embodiment, from the viewpoint of effectively suppressing a decrease in adhesive strength between the support (a) and the photosensitive resin composition layer (b) over a period of one month or more under aging conditions in a high-temperature, high-humidity environment of a temperature of 40° C. and a relative humidity of about 80% RH, in which bleeding out of the plasticizer component in the photosensitive resin composition layer (b) is promoted, 600 mJ / cm is applied from the support (a) side of the flexographic printing original plate. ２ , 8000 mJ / cm from the photosensitive resin composition layer (b) side ２ In AFM force curve measurement of a cross section of a cured product obtained by irradiating the adhesive layer (c) with ultraviolet light, it is preferable that the deformation amount of the adhesive layer (c) is 20 nm or less (the above-mentioned <Condition (1)>). When the deformation amount of the adhesive layer (c) is within the above-mentioned numerical range, the decrease in the adhesive strength over time is significantly suppressed. The deformation amount of the adhesive layer (c) is more preferably 18 nm or less, and even more preferably 16 nm or less.

[0097] In order to satisfy the above-mentioned condition (1), it is effective for the adhesive layer (c) to contain 3% by mass or more and 30% by mass or less of a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule.

[0098] The adhesive layer (c) preferably further contains an ethylenically unsaturated compound (c-2), a photopolymerization initiator (c-3), and an antioxidant (c-4).

[0099] <Reactive Acrylic Resin (c-1) Having Three or More (Meth)acryloyl Groups in the Molecule> When force curve measurement is performed by AFM under the above <Condition (1)>, in order to control the deformation amount of the adhesive layer (c) to 20 nm or less in the AFM force curve measurement of the cross section of the cured product obtained by the ultraviolet irradiation, it is important to significantly improve the crosslinking density of the adhesive layer (c). By using a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule as the material for the adhesive layer (c), the deformation amount of the adhesive layer (c) can be controlled within the above numerical range. Furthermore, compared to styrene-based thermoplastic elastomers and butadiene rubbers, which have conventionally been widely used as binder resins for adhesive layers (c), the reactive acrylic resin (c-1) has high compatibility with the ethylenically unsaturated compound (c-2) contained in the adhesive layer (c), as described below. Therefore, the addition of an organic solvent is not required in the preparation of an adhesive coating solution for forming the adhesive layer (c) on the support (a) of this embodiment using the reactive acrylic resin (c-1) as a binder component. Examples of such organic solvents include, but are not limited to, carbonate solvents such as dimethyl carbonate, ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate and butyl acetate, aliphatic solvents such as n-hexane, alicyclic solvents such as cyclohexane, aromatic solvents such as toluene and xylene, and petroleum fraction solvents such as mineral spirits and industrial gasoline. As described above, the absence of these solvents contributes to reducing the environmental impact.

[0100] The reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule can be obtained by copolymerizing a (meth)acrylic acid alkyl ester and a carboxyl group-containing radically polymerizable monomer by water-mediated suspension polymerization to obtain a carboxyl group-containing acrylic resin, and reacting the carboxyl group-containing acrylic resin with an epoxy group-containing radically polymerizable monomer in an aqueous medium. Here, in this specification, the term "reactive acrylic resin" refers to an acrylic resin having a radically polymerizable unsaturated bond in a side chain in the molecule.

[0101] When the weight-average molecular weight (Mw) of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule in the adhesive layer (c) constituting the flexographic printing plate precursor of this embodiment is large, the Tg of the adhesive layer (c) increases, increasing its rigidity, which tends to reduce the initial adhesive strength between the support (a) and the photosensitive resin composition layer (b) of the flexographic printing plate. From the viewpoint of the initial adhesive strength, the weight-average molecular weight (Mw) of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule is preferably 40,000 or less. Furthermore, when the weight-average molecular weight (Mw) is small, the function as a binder polymer in the adhesive layer (c) decreases, and the initial adhesive strength tends to decrease. From the viewpoint of the initial adhesive strength, the weight-average molecular weight (Mw) of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule is preferably 20,000 or more. From the above viewpoints, the weight average molecular weight (Mw) of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule is preferably 20,000 to 40,000, more preferably 20,000 to 35,000, and even more preferably 20,000 to 30,000. When the weight average molecular weight of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule is 60,000 or less, compatibility with the ethylenically unsaturated compound (c-2) in the adhesive layer (c) is sufficiently good for practical use, and there is an advantage that the addition of an organic solvent is not required in the preparation step of the adhesive layer-forming liquid. Furthermore, when the weight average molecular weight is 14,000 or more, production of the reactive acrylic resin (c-1) tends to be easier. As described above, from the viewpoint of ensuring compatibility with the ethylenically unsaturated compound (c-2) and ease of production, the weight average molecular weight of the reactive acrylic resin (c-1) is preferably from 14,000 to 60,000, more preferably from 16,000 to 50,000, and even more preferably from 18,000 to 40,000. The weight average molecular weight can be measured by gel permeation chromatography (GPC) and is expressed in terms of polystyrene equivalent molecular weight.The weight average molecular weight of the reactive acrylic resin (c-1) can be controlled within the above-mentioned range by adjusting the type and amount of monomer used in the polymerization step and the polymerization time. Here, in this specification, the "initial adhesive strength" refers to the adhesive strength of a flexographic printing plate immediately after production.

[0102] When the double bond equivalent of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups per molecule in the adhesive layer (c) constituting the flexographic printing plate precursor of this embodiment is large, the number of covalent bonds formed at the interface between the photosensitive resin composition layer (b) and the adhesive layer (c) of the flexographic printing plate decreases, and the initial adhesive strength tends to decrease. On the other hand, when the double bond equivalent of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups per molecule is small, the Tg of the adhesive layer (c) of the flexographic printing plate increases, and the rigidity increases, and the initial adhesive strength tends to decrease. From the viewpoint of the initial adhesive strength, the double bond equivalent of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups per molecule is preferably 1,500 to 5,000, more preferably 1,800 to 5,000, and even more preferably 2,000 to 4,700. In this specification, the "double bond equivalent" is defined by the formula: double bond equivalent = weight average molecular weight (Mw) / number of polymerizable double bonds in one molecule, and specifically, can be measured by the method described in the examples below.

[0103] When the content of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule in the adhesive layer (c) decreases, the adhesive strength between the support (a) and the photosensitive resin composition layer (b) in the flexographic printing plate tends to decrease after one month under aging conditions in a high-temperature, high-humidity environment at a temperature of 40°C and a relative humidity of about 80% RH. On the other hand, when the content of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule increases, the initial adhesive strength tends to decrease. Furthermore, when the content of the reactive acrylic resin (c-1) increases, the adhesive layer (c) undergoes more cure shrinkage upon irradiation with ultraviolet light, and therefore, when the support (a) is bent by hand, cracks occur in the adhesive layer (c) or the adhesive layer (c) is more likely to peel off from the substrate (f). The content of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the adhesive layer (c) is selected from the viewpoint of the balance between the adhesive strength after one month, the initial adhesive strength, and ease of handling of the support (a). In this embodiment, when the total amount of the adhesive layer (c) is 100.0 mass%, the content of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule in the adhesive layer (c) is preferably 3 mass% or more and 30 mass% or less, more preferably 4 mass% or more and 25 mass% or less, and even more preferably 5 mass% or more and 20 mass% or less.

[0104] <Ethylenically Unsaturated Compound (c-2)> As described above, the adhesive layer (c) preferably contains an ethylenically unsaturated compound (c-2). The ethylenically unsaturated compound (c-2) is a compound having a radically polymerizable unsaturated double bond. Examples of such ethylenically unsaturated compounds (c-2) include, but are not limited to, olefins such as ethylene, propylene, vinyltoluene, styrene, and divinylbenzene; acetylenes; (meth)acrylic acid and / or derivatives thereof; haloolefins; unsaturated nitriles such as acrylonitrile; unsaturated amides and derivatives thereof such as acrylamide and methacrylamide; unsaturated dicarboxylic acids and derivatives thereof such as maleic anhydride, maleic acid, and fumaric acid; vinyl acetates; N-vinylpyrrolidone; N-vinylcarbazole; and N-substituted maleimide compounds. Among these, (meth)acrylic acid and / or derivatives thereof are preferred from the viewpoints of UV curability and adhesive strength between the photosensitive resin composition layer (b) and the adhesive layer (c) of the flexographic printing plate.

[0105] Examples of the derivatives include, but are not limited to, alicyclic compounds having a cycloalkyl group, a bicycloalkyl group, a cycloalkenyl group, a bicycloalkenyl group, or the like; aromatic compounds having a benzyl group, a phenyl group, a phenoxy group, or a naphthalene skeleton, an anthracene skeleton, a biphenyl skeleton, a phenanthrene skeleton, a fluorene skeleton, a bisphenol A skeleton, or the like; compounds having an alkyl group, a halogenated alkyl group, an alkoxyalkyl group, a hydroxyalkyl group, an aminoalkyl group, a glycidyl group, or the like; ester compounds with polyhydric alcohols such as alkylene glycol, polyoxyalkylene glycol, polyalkylene glycol, and trimethylolpropane; and compounds having a polysiloxane structure such as polydimethylsiloxane and polydiethylsiloxane.

[0106] The ethylenically unsaturated compound (c-2) may also be a heteroaromatic compound containing elements such as nitrogen and sulfur.

[0107] Examples of the (meth)acrylic acid and / or derivatives thereof include, but are not limited to, diacrylates and dimethacrylates of alkanediols such as hexanediol and nonanediol; diacrylates and dimethacrylates of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, and butylene glycol; trimethylolpropane tri(meth)acrylate; dimethyloltricyclodecane di(meth)acrylate; isobornyl(meth)acrylate; phenoxy polyethylene glycol (meth)acrylate; trimethylolpropane benzoate di(meth)acrylate; glycerin di(meth)acrylate; triglycerol di(meth)acrylate; pentaerythritol tri(meth)acrylate; Acrylates; trimethylolpropane (meth)acrylic acid benzoate; bisphenol A diglycidyl ether acrylic acid adduct; bisphenol A diglycidyl ether methacrylic acid adduct; commercially available products include "Epoxy Ester 200PA" (trademark) manufactured by Kyoeisha Chemical Co., Ltd., "Epoxy Ester 3000A" (trademark) manufactured by Kyoeisha Chemical Co., Ltd., "Epoxy Ester 3000MK" (trademark) manufactured by Kyoeisha Chemical Co., Ltd., "Phenyl glycidyl ether (meth)acrylate hexamethylene diisocyanate urethane prepolymer AH-600" (trademark) manufactured by Kyoeisha Chemical Co., Ltd., "Di(meth)acrylated isocyanurate M-215" (trademark) manufactured by Toagosei Co., Ltd., bisphenol A diglycidyl ether methacrylic acid adduct; pentaerythritol tetra(meth)acrylate, etc. These may be used alone or in combination of two or more types.

[0108] From the viewpoint of the initial adhesive strength between the support (a) and the photosensitive resin composition layer (b) of the flexographic printing plate, it is preferable to use at least one type of (meth)acrylate as the ethylenically unsaturated compound (c-2), and it is more preferable to use at least one type of bifunctional (meth)acrylate.

[0109] A bifunctional or higher functional (meth)acrylate compound having one or more aromatic rings and / or one or more hydroxyl groups in the molecule can form strong intermolecular interactions with the adhesive layer components of the support (a) through hydrogen bonding or π-π interactions, contributing to improving the initial adhesive strength of the flexographic printing plate. Therefore, it is preferable to use, as the ethylenically unsaturated compound (c-2), a bifunctional or higher functional (meth)acrylate compound having one or more aromatic rings and / or one or more hydroxyl groups in the molecule, such as at least one bifunctional (meth)acrylate having a bisphenol A skeleton. A decrease in the content of the bifunctional (meth)acrylate having a bisphenol A skeleton in the adhesive layer (c) tends to decrease the initial adhesive strength of the flexographic printing plate. From the viewpoint of the initial adhesive strength, the content of the bifunctional (meth)acrylate having a bisphenol A skeleton in the adhesive layer (c) is preferably 15% by mass to 60% by mass, more preferably 20% by mass to 55% by mass, and even more preferably 25% by mass to 50% by mass.

[0110] A decrease in the content of the ethylenically unsaturated compound (c-2) in the adhesive layer (c) tends to decrease the initial adhesive strength of the flexographic printing plate. From the viewpoint of the initial adhesive strength, when the total amount of the adhesive layer (c) is taken as 100.0 mass%, the content of the ethylenically unsaturated compound (c-2) in the adhesive layer (c) is preferably 10.0 mass% or more and 90.0 mass% or less, more preferably 20.0 mass% or more and 90.0 mass% or less, even more preferably 30.0 mass% or more and 90.0 mass% or less, and even more preferably 40.0 mass% or more and 90.0 mass% or less.

[0111] The number average molecular weight (Mn) of the ethylenically unsaturated compound (c-2) is preferably 100 or more from the viewpoint of improving the non-volatility of the ethylenically unsaturated compound (c-2) during storage, and is preferably less than 1,000, more preferably 200 or more and 800 or less, from the viewpoint of compatibility with other components.

[0112] <Photopolymerization initiator (c-3)> The adhesive layer (c) preferably contains a photopolymerization initiator (c-3). The photopolymerization initiator (c-3) is a compound that absorbs light energy and generates radicals, and examples of the photopolymerization initiator include a degradable photopolymerization initiator, a hydrogen abstraction photopolymerization initiator, and a compound having a moiety that functions as a hydrogen abstraction photopolymerization initiator and a moiety that functions as a degradable photopolymerization initiator in the same molecule.

[0113] Examples of such photopolymerization initiators (c-3) include, but are not limited to, benzophenone, 4,4-bis(diethylamino)benzophenone, 3,3',4,4'-benzophenonetetracarboxylic anhydride, 3,3',4,4'-tetramethoxybenzophenone, and other benzophenones; anthraquinones, such as t-butylanthraquinone and 2-ethylanthraquinone; thioxanthones, such as 2,4-diethylthioxanthone, isopropylthioxanthone, and 2,4-dichlorothioxanthone; Michler's ketone; diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-methyl-1-( acetophenones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, trichloroacetophenone, etc.; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc.; acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, etc.; methylbenzoyl formate; 1,7-bisacridinylheptane; 9-phenylacridine; azo compounds such as azobisisobutyronitrile, diazonium compounds, and tetrazene compounds. These may be used alone or in combination of two or more. Among these, compounds having a carbonyl group are preferred from the viewpoint of the ultraviolet curability of the adhesive layer (c), and aromatic carbonyl compounds such as benzophenones and thioxanthones are more preferred.

[0114] When the content of the photopolymerization initiator (c-3) in the adhesive layer (c) is reduced, the formation of covalent bonds at the interface between the photosensitive resin composition layer (b) and the adhesive layer (c) of the flexographic printing plate is insufficient, and the initial adhesive strength between the support (a) and the photosensitive resin composition layer (b) of the flexographic printing plate tends to decrease. On the other hand, when the content of the photopolymerization initiator (c-3) is increased, the rigidity of the adhesive layer (c) of the flexographic printing plate increases, and the initial adhesive strength tends to decrease. From the viewpoint of the initial adhesive strength, when the total amount of the adhesive layer (c) is taken as 100% by mass, the content of the photopolymerization initiator (c-3) is preferably 0.1% by mass or more and 7.0% by mass or less, more preferably 0.5% by mass or more and 7.0% by mass or less, and even more preferably 1.0% by mass or more and 5.0% by mass or less.

[0115] <Antioxidant (c-4)> The adhesive layer (c) preferably contains an antioxidant (c-4). Antioxidants commonly used in the fields of resin materials or rubber materials can be used. Specific examples include phenolic materials. Examples of such phenolic materials include, but are not limited to, vitamin E, tetrakis-(methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate)methane, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol. One type of antioxidant may be used alone, or two or more types may be used in combination.

[0116] <Auxiliary Additive Components> Examples of auxiliary additive components include, but are not limited to, ultraviolet absorbers, dyes, pigments, and the like. Examples of ultraviolet absorbers include, but are not limited to, known benzophenone-based compounds, salicylate-based compounds, acrylonitrile-based compounds, metal complex salt-based compounds, and hindered amine-based compounds. The dyes and pigments listed below may also be used as ultraviolet absorbers. Examples of such ultraviolet absorbers include, but are not limited to, 2-ethoxy-2'-ethyloxalic acid bisanilide and 2,2'-dihydroxy-4-methoxybenzophenone. Dyes and pigments are effective as coloring means for improving visibility. Examples of dyes include, but are not limited to, water-soluble basic dyes, acid dyes, direct dyes, and the like, as well as water-insoluble sulfide dyes, oil-soluble dyes, disperse dyes, and the like. Anthraquinone dyes, indigoid dyes, and azo dyes are particularly preferred, with azo oil-soluble dyes and the like being more preferred. Examples of pigments include, but are not limited to, natural pigments, synthetic inorganic pigments, and synthetic organic pigments. Examples of synthetic organic pigments include azo pigments, triphenylmethane pigments, quinoline pigments, anthraquinone pigments, and phthalocyanine pigments. The total amount of the auxiliary additive components described above is preferably 0.1% by mass or more and 10.0% by mass or less, more preferably 0.1% by mass or more and 5.0% by mass or less, and even more preferably 0.1% by mass or more and 3.0% by mass or less, when the total amount of the adhesive layer (c) is taken as 100.0% by mass.

[0117] (Protective Layer) The photosensitive resin composition constituting the photosensitive resin composition layer (b) is usually adhesive. Therefore, a solvent-soluble protective layer may be provided on the surface of the photosensitive resin composition layer (b) to improve contact with the negative film that is laid on top of it during the making of a flexographic printing plate, or to enable the reuse of the negative film. The protective layer preferably contains, for example, a substance that is soluble in the solvent used as a washout solution and is thin and flexible. Examples of protective layers include protective layers containing crystalline 1,2-polybutadiene, soluble polyamides, partially saponified polyvinyl acetate, cellulose esters, etc., with soluble polyamides being preferred. These substances may be dissolved in an appropriate solvent and the resulting solution directly coated on the surface of the photosensitive resin composition layer (b). Alternatively, the substance may be first coated on a film such as polyester or polypropylene, and the film coated with the substance may be laminated and transferred onto the photosensitive resin composition layer (b).

[0118] (Infrared ablation layer (d)) In the flexographic printing original plate of this embodiment, an infrared ablation layer (d) containing an infrared-sensitive material may be laminated on the photosensitive resin composition layer (b) instead of the above-mentioned protective layer. The infrared ablation layer (d) is preferably composed of a binder polymer, an infrared-sensitive material, and a non-infrared radiation-shielding material.

[0119] Examples of binder polymers include polyamides, polyesters, and copolymers of monovinyl-substituted aromatic hydrocarbons and conjugated dienes. Among these, copolymers of monovinyl-substituted aromatic hydrocarbons, such as styrene, α-methylstyrene, and vinyltoluene, and conjugated dienes, such as 1,3-butadiene and isoprene, are preferred. When the infrared ablation layer (d) is formed using such binder polymers, it exhibits high affinity with the photosensitive resin composition and good adhesion. Furthermore, when polyester is used as the binder polymer, the number-average molecular weight of the polyester is preferably 300 or more and 10,000 or less. Suitable examples of polyesters include those synthesized from alkanediols and adipic acid, those synthesized from alkanediols and phthalic acid, polycaprolactone, and combinations of two or more of these polyesters. Furthermore, the polyester may contain various functional groups, such as amino groups, nitro groups, sulfonic acid groups, and halogens, as long as they do not impair compatibility with other binder polymers, infrared-sensitive materials, or non-infrared radiation-shielding materials.

[0120] Suitable infrared-sensitive materials are, for example, simple substances or compounds that have strong absorption in the range of 750 to 2000 nm. Specific examples of infrared-sensitive materials include inorganic pigments such as carbon black, graphite, copper chromite, and chromium oxide; and dyes such as polyphthalocyanine compounds, cyanine dyes, and metal thiolate dyes. These infrared-sensitive materials are added in an amount that provides sensitivity sufficient for ablation with the laser beam used. Addition of 10 to 80% by mass is generally effective.

[0121] As the non-infrared radiation shielding material, a material that reflects or absorbs radiation such as ultraviolet light can be used. Radiation absorbers for ultraviolet light, carbon black, graphite, etc. are good examples, and the amount added is determined so as to achieve the required optical density. It is generally preferable to add the material so as to achieve an optical density of 2 or more, preferably 3 or more.

[0122] [Method for manufacturing a flexographic printing plate] The method for manufacturing a flexographic printing plate of this embodiment includes the following steps: a first step of irradiating the support (a) with ultraviolet light using the flexographic printing original plate of this embodiment; a second step of placing a negative film on the photosensitive resin composition layer (b) or laser ablating the infrared ablation layer (d) provided on the photosensitive resin composition layer (b) by irradiating it with infrared light to form a negative pattern; a third step of irradiating the photosensitive resin composition layer (b) with ultraviolet light through the negative film or using the infrared ablation layer (d) on which the pattern has been drawn as a mask to perform pattern exposure; and a fourth step of removing unexposed areas of the photosensitive resin composition layer (b). Thereafter, a post-exposure treatment step is performed as necessary to obtain a flexographic printing plate (relief printing plate) made of a cured product of the photosensitive resin composition layer (b). From the viewpoint of imparting releasability to ink and printed materials, the surface of the flexographic printing plate may be brought into contact with a liquid containing a silicone compound and / or a fluorine compound.

[0123] 2 is a schematic diagram showing a method for producing a flexographic printing plate using a flexographic printing plate precursor of this embodiment. Each step will be described in detail below.

[0124] (First Step: S1) In the first step, the method of irradiating the photosensitive resin composition layer (b) with ultraviolet light from the support (a) side is not particularly limited, and can be carried out using a known irradiation unit. The wavelength of the ultraviolet light irradiated here is preferably 150 to 500 nm, more preferably 300 to 400 nm. The light source of the ultraviolet light is not limited to the following, but examples that can be used include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, zirconium lamps, carbon arc lamps, and ultraviolet fluorescent lamps. Note that this first step may be carried out before or after the second step described below.

[0125] (Second Step: S2) In the second step, the method for irradiating the infrared ablation layer (d) with infrared rays to draw and process a pattern is not particularly limited, and can be performed using a known irradiation unit. Note that infrared irradiation of the infrared ablation layer (d) can be performed from the infrared ablation layer (d) side. If the flexographic printing plate precursor of this embodiment has a cover film, the cover film is first peeled off before infrared irradiation. Then, infrared rays are irradiated onto the infrared ablation layer (d) in a pattern to decompose the resin in the irradiated areas, thereby drawing and processing a pattern. This allows a mask (d') of the infrared ablation layer (d) to be formed on the photosensitive resin composition layer (b). Suitable infrared lasers for the second step include, for example, an ND / YAG laser (e.g., 1064 nm) or a diode laser (e.g., 830 nm). Laser systems suitable for CTP platemaking technology are commercially available, and for example, a diode laser system CDI Spark (ESKO GRAPHICS) can be used. This laser system includes a rotating cylindrical drum that holds the flexographic printing original plate of this embodiment, an IR laser irradiation device, and a layout computer, and image information is sent directly from the layout computer to the laser device.

[0126] (Third Step: S3) In the third step, the photosensitive resin composition layer (b) is irradiated with ultraviolet light using the infrared ablation layer (d) on which the pattern has been drawn as a mask to perform pattern exposure, thereby forming a printing pattern (b'). At this time, the light that has passed through the mask promotes the curing reaction of the photosensitive resin composition layer (b), and the pattern formed in the infrared ablation layer (d) is transferred to the photosensitive resin composition layer (b) with the concaves and convexes reversed. The ultraviolet light irradiation may be performed on the entire surface of the flexographic printing plate blank of this embodiment. The third step can be performed with the flexographic printing plate blank of this embodiment attached to a laser cylinder, but generally the flexographic printing plate blank of this embodiment is removed from the laser device and irradiated using a conventional irradiation unit. The irradiation unit can be the same as the unit exemplified for ultraviolet light irradiation in the first step.

[0127] (Fourth Step: S4) The fourth step is a step of removing the infrared ablation layer (d) and the unexposed areas of the photosensitive resin composition layer (b). The removal method in the fourth step (development step) is not particularly limited, and a conventionally known method can be applied. Specifically, as described above, the photosensitive resin composition layer (b) of the flexographic printing plate precursor of this embodiment is exposed to light to form a printing pattern (b'), and then the unexposed areas are washed away with a solvent for solvent development or a cleaning solution for water development, or the unexposed areas are brought into contact with a predetermined absorbing layer that can absorb the unexposed areas and that has been heated to 40°C to 200°C, and the absorbing layer is removed to remove the unexposed areas. Thereafter, a post-exposure treatment is performed as necessary, thereby producing a flexographic printing plate. Note that when an intermediate layer (e) is present between the infrared ablation layer (d) and the photosensitive resin composition layer (b), it may be removed simultaneously in the development step. Developing solvents used for solvent development of unexposed areas include, but are not limited to, esters such as heptyl acetate and 3-methoxybutyl acetate; hydrocarbons such as petroleum fractions, toluene, and decalin; and mixtures of chlorinated organic solvents such as tetrachloroethylene with alcohols such as propanol, butanol, and pentanol. The unexposed areas are washed out by spraying from a nozzle or by brushing. Suitable cleaning solutions for water development include water, alkaline aqueous solutions, neutral detergents, and surfactants.

[0128] Examples of surfactants include anionic surfactants, amphoteric surfactants, and nonionic surfactants. These may be used alone or in combination of two or more. Examples of anionic surfactants include, but are not limited to, sulfate ester salts, higher alcohol sulfate esters, higher alkyl ether sulfate ester salts, sulfated olefins, alkylbenzene sulfonates, α-olefin sulfonates, phosphate ester salts, and dithiophosphate ester salts. Examples of amphoteric surfactants include, but are not limited to, amino acid-type amphoteric surfactants and betaine-type amphoteric surfactants. Examples of nonionic surfactants include, but are not limited to, polyethylene glycol surfactants such as higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher alkylamine ethylene oxide adducts, fatty acid amide ethylene oxide adducts, and polypropylene glycol ethylene oxide adducts; and polyhydric alcohol surfactants such as glycerol fatty acid esters, pentaerythritol fatty acid esters, sorbitol and sorbitan fatty acid esters, polyhydric alcohol alkyl esters, and alkanolamine fatty acid amides.

[0129] The alkaline aqueous solution may also contain a pH adjuster. The pH adjuster may be either an organic or inorganic material, but is preferably one that can adjust the pH to 9 or higher. Examples of pH adjusters include, but are not limited to, sodium hydroxide, sodium carbonate, potassium carbonate, sodium silicate, sodium metasilicate, and sodium succinate. The absorption layer for thermal development is not particularly limited, but examples include, but are not limited to, nonwoven fabric materials, paper materials, woven fiber fabrics, open-cell foams, and porous materials. Among these, nonwoven fabric materials made of nylon, polyester, polypropylene, or polyethylene, and combinations of these nonwoven fabric materials, are preferred, and continuous nonwoven webs of nylon or polyester are more preferred.

[0130] [Flexographic Printing Method] The flexographic printing method of this embodiment includes the following steps: a first step of irradiating ultraviolet light from the support (a) side using the flexographic printing original plate of this embodiment described above; a second step of irradiating infrared light onto the infrared ablation layer (d) to draw a pattern; a third step of irradiating ultraviolet light onto the photosensitive resin composition layer (b) using the infrared ablation layer (d) on which the pattern has been drawn as a mask to perform pattern exposure; a fourth step of removing unexposed areas of the infrared ablation layer (d) and the photosensitive resin composition layer (b) to produce a flexographic printing plate; and a fifth step of printing using the flexographic printing plate. The first to fourth steps in the flexographic printing method are as described above. (Fifth Step) The fifth step is a step of printing using the flexographic printing plate obtained by the first to fourth steps. The printing method using a flexographic printing plate is not particularly limited as long as it is a method in which ink is applied to the raised portions of the flexographic printing plate and the ink is transferred to a substrate.

[0131] [Support] The support (a) of this embodiment is a support (a) for a flexographic printing original plate having a substrate (f) and an adhesive layer (c). In the support of this embodiment, the adhesive layer (c) contains a reactive acrylic resin (c-1) having three or more (meth)acroyl groups in its molecule. The adhesive layer (c) preferably contains 3% by mass or more and 30% by mass or less of the reactive acrylic resin (c-1) having three or more (meth)acroyl groups in its molecule. The double bond equivalent of the reactive acrylic resin (c-1) having three or more (meth)acroyl groups in its molecule is preferably 1,500 or more and 5,000 or less. The weight-average molecular weight of the reactive acrylic resin (c-1) having three or more (meth)acroyl groups in its molecule is preferably 14,000 or more and 60,000 or less. The adhesive layer (c) preferably contains a bifunctional or higher (meth)acrylate compound having one or more aromatic rings and / or one or more hydroxyl groups in its molecule. The above-described explanation of the flexographic printing plate precursor of this embodiment can be applied to the base material (f) and adhesive layer (c) that constitute the support (a).

[0132] Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples and comparative examples.

[0133] [Production of Flexographic Printing Plate: Example A and Comparative Example A] (Preparation of Laminate for Forming Infrared Ablation Layer) 65% by mass of Asaflex 810 (registered trademark, manufactured by Asahi Kasei Corporation), a block copolymer of styrene and 1,3-butadiene, and 35% by mass of carbon black as an infrared-sensitive material were kneaded in a kneader and cut into pellets. 90 parts by mass of these pellets and 10 parts by mass of 1,6-hexanediol adipate were then dissolved using ultrasound in a mixed solvent prepared in a mass ratio of ethyl acetate / butyl acetate / propylene glycol monomethyl ether acetate = 50 / 30 / 20 to prepare a homogeneous solution with a solids content of 12% by mass. Next, this solution was applied to a polyester film having a thickness of 100 μm to serve as a cover sheet, so that the coating amount after drying was 4 to 5 g / m ２ The coating was applied using a knife coater so that the coating was as follows: and then dried at 80°C for 1 minute to obtain a film having an ultraviolet-shielding layer (infrared ablation layer) that can be ablated by infrared rays. The optical density of this film having an infrared ablation layer was measured using a DM-500 (trademark, manufactured by Dainippon Screen Mfg. Co., Ltd.) and found to be 3 to 4.

[0134] (Preparation of Photosensitive Resin Composition) <Photosensitive Resin Composition 1> 60 parts by mass of Tufprene A (styrene-butadiene-styrene block copolymer, manufactured by Asahi Kasei Corporation), 30 parts by mass of B-2000 (liquid polybutadiene, manufactured by Nippon Petrochemical Co., Ltd.), 7 parts by mass of 1,9-nonanediol diacrylate, 2 parts by mass of 2,2-dimethoxy-2-phenylacetophenone, and 0.3 parts by mass of 2,6-di-t-butyl-p-cresol were kneaded in a pressure kneader to prepare photosensitive resin composition 1 (referred to as resin 1 in Tables 4 and 5 below).

[0135] <Photosensitive Resin Composition 2> 60 parts by mass of Tufprene A (styrene-butadiene-styrene block copolymer, manufactured by Asahi Kasei Corporation), 10 parts by mass of B-2000 (liquid polybutadiene, manufactured by Nippon Petrochemicals), 20 parts by mass of a monomer dilution of reactive acrylic resin a1 (described below) (resin concentration 40% by mass), 7 parts by mass of 1,9-nonanediol diacrylate, 2 parts by mass of 2,2-dimethoxy-2-phenylacetophenone, and 0.3 parts by mass of 2,6-di-t-butyl-p-cresol were kneaded in a pressure kneader to prepare photosensitive resin composition 2 (referred to as resin 2 in Tables 4 and 5 below).

[0136] <Photosensitive Resin Composition 3> A pressure-resistant reaction vessel equipped with a stirrer and a temperature-controlling jacket was initially charged with 125 parts by mass of water and 2 parts by mass of "ADEKA REASOAP" (manufactured by ADEKA Corporation) as a reactive emulsifier, an ammonium salt of (α-sulfo(1-nonylphenoxy)methyl-2-(2-propenyloxy)ethoxy-poly(oxy-1,2-ethanediyl), and the internal temperature was raised to 80°C. 10 parts by mass of styrene, 60 parts by mass of butadiene, 23 parts by mass of butyl acrylate, 5 parts by mass of methacrylic acid, An oily mixed solution of a monomer mixture consisting of 2 parts by mass of acrylic acid and 2 parts by mass of t-dodecyl mercaptan, and an aqueous solution consisting of 28 parts by mass of water, 1.2 parts by mass of sodium peroxodisulfate, 0.2 parts by mass of sodium hydroxide, and 2 parts by mass of the ammonium salt of (α-sulfo(1-nonylphenoxy)methyl-2-(2-propenyloxy)ethoxy-poly(oxy-1,2-ethanediyl) were added at a constant flow rate over 5 hours, and over 6 hours, respectively. The temperature of 80°C was then maintained for 1 hour to complete the polymerization reaction, and polymer particles were obtained, followed by cooling. The pH of the resulting polymer particles was adjusted to 7 with sodium hydroxide, after which unreacted monomers were removed by steam stripping, and the mixture was filtered through a 200-mesh wire net. Finally, the solids concentration of the filtrate was adjusted to 40% by mass, yielding an aqueous dispersion of polymer particles. The resulting aqueous dispersion of polymer particles was dried in a vacuum dryer at 50°C to remove water, yielding polymer particles. 30 parts by mass of the polymer particles, 30 parts by mass of Tufprene A (styrene-butadiene-styrene block copolymer, manufactured by Asahi Kasei Corporation), 30 parts by mass of B-2000 (liquid polybutadiene, manufactured by Nippon Petrochemical Co., Ltd.), 7 parts by mass of 1,9-nonanediol diacrylate, 2 parts by mass of 2,2-dimethoxy-2-phenylacetophenone, and 0.3 parts by mass of 2,6-di-t-butyl-p-cresol were kneaded in a pressure kneader to prepare photosensitive resin composition 3 (referred to as resin 3 in Table 4 below).

[0137] (Preparation of Substrate) A polyester film having an undercoat layer was used as the substrate. The polyester film having an undercoat layer was prepared as follows: 93 g of ethylene glycol, 374 g of neopentyl glycol, and 382 g of phthalic acid were reacted in an air atmosphere at a reaction temperature of 180° C. with a 1.33×10 ３ After a condensation reaction was carried out for 6 hours under a reduced pressure of 100 Pa, 125 g of 4,4-diphenylenediisocyanate was added and the reaction was further carried out for 5 hours at 80°C to obtain a resin. The resin was made into a 10% aqueous solution and applied to a melt-extruded polyethylene terephthalate film. After application, the film was biaxially stretched to obtain a polyester film having an undercoat layer. The thickness of the obtained undercoat layer was 0.05 µm.

[0138] (Preparation of reactive acrylic resin a for adhesive layer) <Reactive acrylic resin a1> Step (1): 823.5 parts of methyl methacrylate, 337.5 parts of ethyl acrylate, 90 parts of methacrylic acid, 6.75 parts of n-dodecyl mercaptan, and 7.95 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) were placed in a container and dissolved in advance at a temperature of 40°C or less (hereinafter, this solution is referred to as "mixed solution A"). Then, 3,375 parts of water and 14 parts of polyvinyl alcohol as a dispersant were added to a four-necked, round-bottomed, 5-L glass flask equipped with a stirrer and dissolved. While stirring at 400 rpm with a stirring blade, the pre-dissolved mixed solution A was added all at once to prepare a suspension. Next, with continued stirring, the reaction system of this suspension was heated to 65°C and allowed to react (suspension polymerization) for 3 hours while maintaining the temperature constant. The mixture was then heated to 90°C and allowed to react (suspension polymerization) for 2 hours while maintaining the temperature constant. The mixture was then cooled to room temperature (approximately 25°C). The reaction product was then subjected to solid-liquid separation, thoroughly washed with water, and dried at 40°C for 24 hours using a dryer. After drying, a powdery carboxyl group-containing acrylic resin was obtained at room temperature. Step (2): Next, 600 parts of water and 2 parts of polyvinyl alcohol as a dispersant were added to a 1-L four-necked round-bottom glass flask equipped with a stirrer and dissolved. While stirring at 400 rpm with a stirring blade, 200 parts of the carboxyl group-containing acrylic resin obtained in step (1) was added and dispersed. Furthermore, 2 parts of 2-methylimidazole were added and mixed as an amine compound. The reaction system of this mixture was then heated to 50°C while continuing to stir, and the temperature was maintained constant for 1 hour. Next, 20 parts of methacrylic acid glycidyl ester was added, and the reaction system was heated to 50°C and kept at a constant temperature for 1 hour while the mixture was impregnated with methacrylic acid glycidyl ester, and homogenization of the reaction system was attempted. The temperature was then raised to 90°C and the reaction was carried out while keeping the temperature constant for 3 hours. The reaction mixture was then cooled to room temperature (approximately 25°C). The reaction product was then separated into solid and liquid, thoroughly washed with water, and dried at 40°C for 24 hours using a dryer to obtain a powdered reactive acrylic resin.Next, the obtained powdery reactive acrylic resin was mixed with a mixed monomer consisting of isobornyl acrylate and 4-hydroxybutyl acrylate (isobornyl acrylate / 4-hydroxybutyl acrylate=1 / 1) to obtain a monomer dilution of reactive acrylic resin a1 (resin concentration 40% by mass).

[0139] <Reactive acrylic resin a2> A monomer dilution of reactive acrylic resin a2 (resin concentration 40 mass%) was prepared in the same manner as in the reactive acrylic resin a1 described above, except that the amount of 2,2'-azobis(2,4-dimethylvaleronitrile) added in the step (1) was changed to 7.8 parts.

[0140] <Reactive acrylic resin a3> A monomer dilution of reactive acrylic resin a3 (resin concentration 40% by mass) was prepared in the same manner as for reactive acrylic resin a1, except that the amount of 2,2'-azobis(2,4-dimethylvaleronitrile) added in step (1) was changed to 7.5 parts.

[0141] <Reactive acrylic resin a4> A monomer dilution of reactive acrylic resin a4 (resin concentration 40 mass%) was prepared in the same manner as for reactive acrylic resin a1, except that the amount of methacrylic acid glycidyl ester added in the step (2) was changed to 14 parts.

[0142] <Reactive acrylic resin a5> A monomer dilution of reactive acrylic resin a5 (resin concentration 40% by mass) was prepared in the same manner as for reactive acrylic resin a1, except that the amount of methacrylic acid added in the step (1) was changed to 189 parts and the amount of methacrylic acid glycidyl ester added in the step (2) was changed to 50 parts.

[0143] <Reactive acrylic resin a6> A monomer dilution of reactive acrylic resin a6 (resin concentration 40% by mass) was prepared in the same manner as for reactive acrylic resin a1, except that the amount of methacrylic acid added in the step (1) was changed to 120 parts, the amount of 2,2'-azobis(2,4-dimethylvaleronitrile) added in the step (1) was changed to 7.8 parts, and the amount of methacrylic acid glycidyl ester added in the step (2) was changed to 14 parts.

[0144] (Preparation of Adhesive Layer) <Adhesive Layer a1> 41.1 parts by mass of bisphenol A diglycidyl ether methacrylic acid adduct, 13.4 parts by mass of reactive acrylic resin a1 monomer dilution (resin concentration 40% by mass), 32.6 parts by mass of 1,9-nonanediol diacrylate, 11.0 parts by mass of 1,6-hexanediol dimethacrylate, 1.5 parts by mass of 2,2-dimethoxy-2-phenylacetophenone, 0.4 parts by mass of 2-methyl-4,6-bis[(octylthio)methyl]-phenol were added and mixed for 2 hours to prepare adhesive coating liquid a1 (referred to as adhesive a1 in Table 1). Next, on the polyester film having an undercoat layer, i.e., the substrate, using a bar coater, the adhesive coating liquid a1 was applied so that the coating thickness was 8 μm, and a plain polyester film was laminated thereon. Thereafter, using an "AFP-1216" exposure machine, 30 mJ / cm from the plain polyester film side was applied. ２ The exposure intensity was measured using a UV illuminance meter "MO-2 type" (trademark) manufactured by Oak Manufacturing Co., Ltd., with a UV-35 filter.

[0145] <Adhesive Layers a2 to a15> Adhesive coating solutions a2 to a15 (referred to as adhesives a2 to a15 in Tables 1 and 2) were obtained in the same manner as for adhesive coating solution 1a, except that the compositions were changed as shown in the following Tables 1 and 2. Next, adhesive layers a2 to a15 were obtained by applying them to a substrate in the same manner as for adhesive layer a1.

[0146] The properties of UH2000, UP1080, and KX-405 in Tables 1 and 2 are as follows: UH-2000: Acrylic polymer manufactured by Toagosei Co., Ltd. UP-1080: Acrylic polymer manufactured by Toagosei Co., Ltd. D-KX405: Styrene-butadiene-styrene copolymer manufactured by Kraton Corporation

[0147] <Adhesive Layer a16> A mixture of 78.1 parts by mass of the adhesive base agent ["Vylon" (registered trademark) 31SS: manufactured by Toyobo Co., Ltd.] and 0.6 parts by mass of PS-8A [manufactured by Wako Pure Chemical Industries, Ltd.] was heated at 70°C for 2 hours, then cooled to 30°C, and 2.1 parts by mass of ethylene glycol diglycidyl ether dimethacrylate was added and mixed for 2 hours. Furthermore, 15.0 parts by mass of the adhesive base agent ["Coronate" (registered trademark) 3015E: manufactured by Tosoh Corporation] and 4.2 parts by mass of an industrial adhesive [EC-1368: manufactured by Sumitomo 3M Limited] were added and mixed to prepare adhesive coating liquid a16. Next, the coating liquid was applied to a polyester film having an undercoat layer, i.e., a substrate, using a bar coater to a thickness of 20 μm after drying, and the solvent was removed by heating in an oven at 180°C for 3 minutes to obtain adhesive layer a16.

[0148] The compositions of the adhesive layers are shown in Tables 1 and 2 below.

[0149]

[0150]

[0151] (Production of flexographic printing original plates of Examples A1 to A12 and Comparative Examples A1 to A6) The above-described photosensitive resin composition was charged into an extrusion molding machine, and a support having an adhesive layer formed thereon as described above was laminated to one side of the photosensitive resin composition layer extruded from a T-shaped die. A release film (Diafoil MRV100, manufactured by Mitsubishi Chemical Corporation) was laminated to the side of the photosensitive resin composition layer opposite the support laminate side, thereby obtaining a laminate of the support (substrate and adhesive layer) and the photosensitive resin composition layer. Next, the release film was peeled off, and a laminate for forming an infrared ablation layer was laminated so that the infrared ablation layer was in contact with the photosensitive resin composition layer, thereby obtaining a flexographic printing original plate.

[0152] (Production of Flexographic Printing Plates of Examples A1 to A11 and Comparative Examples A1 to A6) The support side of the flexographic printing plate precursor was exposed using an "AFP-1216" exposure machine so that the pattern height (RD) after curing was about 0.7 mm. Next, the cover film of the infrared ablation layer was peeled off, and an image was drawn on the infrared ablation layer using a laser drawing machine (CDI) manufactured by ESKO. Then, the infrared ablation layer side was exposed to 8000 mJ / cm 2 using the exposure machine. ２ Next, development was carried out using an "AFP-1321P" developing machine (manufactured by Asahi Kasei Corporation, trademark) at a liquid temperature of 30°C and a speed of 135 mm / min with Sorbitol (manufactured by MacDermid, trademark, mixed organic solvent of 60% by mass of hydrocarbons and 40% by mass of aliphatic alcohol, boiling point 155 to 205°C) as a developer, and the plate was dried at 60°C for 2 hours. Thereafter, as a post-processing exposure, a germicidal lamp having a center wavelength of 254 nm was used to apply 2000 mJ / cm2 to the entire plate surface. ２ , followed by 1000 mJ / cm using a UV fluorescent lamp. ２ The flexographic printing plate was obtained by exposing the substrate to light.

[0153] (Production of Flexographic Printing Plate of Example A12) The support side of the flexographic printing plate precursor was exposed using an "AFP-1216" exposure machine so that the pattern height (RD) after curing was about 0.7 mm. Next, the cover film of the infrared ablation layer was peeled off, and an image was drawn on the infrared ablation layer using a laser drawing machine (CDI) manufactured by ESKO. Then, 8000 mJ / cm was applied from the infrared ablation layer side using the exposure machine. ２ The plate was then developed at 40°C using a developer containing an aqueous solution of 1% polyoxyalkylene alkyl ether (Newcol 2308, manufactured by Nippon Nyukazai Co., Ltd.) and 1% potassium carbonate in a cleaning machine (JOW-A3-P) manufactured by Nippon Denshi Seiki Co., Ltd., and dried at 50°C for 10 minutes. Thereafter, as post-processing exposure, the entire plate surface was exposed to 2000 mJ / cm using a germicidal lamp having a central wavelength of 254 nm. ２ , followed by 1000 mJ / cm using a UV fluorescent lamp. ２ The flexographic printing plate was obtained by exposing the substrate to light.

[0154] [Measurement of Physical Properties] <Method for Measuring Double Bond Equivalent of Reactive Acrylic Resin> The double bond equivalent was calculated from the amount of double bonds in a sample, which was quantified based on the iodine value measured by the method of JIS K0070 (established in 1992), and the mass or molecular weight of the sample. The measurement results of the double bond equivalents of the reactive acrylic resins a1 to a6 are shown in Table 3 below.

[0155] <Method for measuring the weight-average molecular weight (Mw) of a reactive acrylic resin by gel permeation column chromatography (GPC)> [1. Sample preparation] 10 g of tetrahydrofuran was added to 0.5 g of the measurement target, and the mixture was left to dissolve for 2 hours while applying ultrasound. The mixture was then filtered through a polytetrafluoroethylene membrane filter (pore size 3 μm, manufactured by ADVANTEC), and the filtrate was used as the measurement sample. [2. Apparatus, measurement conditions, etc.] GPC measurement of a monomer dilution of a reactive acrylic resin was carried out using the following apparatus and measurement conditions. Note that the obtained GPC chart has multiple peaks, but in this embodiment, the peak with the largest weight-average molecular weight was taken as the peak corresponding to the reactive acrylic resin. Apparatus: HLC-8220 manufactured by Tosoh Corporation GPC Column: Four of the following columns were connected in series for separation. TSKgel GMH XL manufactured by Tosoh TSKgel GMH XL manufactured by Tosoh TSKgel GMH XLL manufactured by Tosoh TSKgel GMH XLL manufactured by Tosoh Column temperature: 40°C Solvent: tetrahydrofuran Flow rate: 1 mL / min Detector: RI Calibration curve: standard polystyrene The measurement results of the weight average molecular weights of the reactive acrylic resins 1 to 6 are shown in Table 3 below.

[0156] <Measurement of Force Curve by AFM> [1. Preparation of Sample from Flexographic Printing Plate] After wiping the infrared ablation layer constituting the flexographic printing plate with a nonwoven fabric using a solvent such as acetone, the flexographic printing plate was exposed to 600 mJ / cm from the support side using an "AFP-1216" exposure machine. ２ , 8000 mJ / cm from the photosensitive resin composition layer side ２The cured product was then exposed to ultraviolet light of 1000 kJ / cm. Subsequently, the cured product was cut into small pieces of 1 cm square, frozen at -180°C, and the cross section was cut using a cryomicrotome (manufactured by Leica) to produce a smooth cross section, which was used as a measurement sample. [2. Apparatus and Measurement Conditions] Force curve measurement was carried out using an AFM using the following apparatus and measurement conditions. Apparatus: Dimension Icon-IR (manufactured by Bruker) Measurement mode: QNM in air Measurement probe: RTESPA-300 (k=19.6 N / m) Measurement load: 200 nN [3. Measurement points and calculation method of characteristic values] A shape image of Example A1 obtained using the above-mentioned apparatus and measurement conditions is shown in Figure 3. In the shape image, force curve measurements were performed at 10 points in the adhesive layer equidistant from the interface with the substrate and the interface with the photosensitive resin composition layer, and the average measurement value was taken as the deformation amount of the adhesive layer in the cured laminate. Note that in this specification, the deformation amount is defined as the amount of displacement of the measurement probe from when the tip of the measurement probe contacts the measurement point until the measurement load reaches 200 nN. The results of the force curve measurements using the AFM described above are shown in Tables 4 and 5 below.

[0157] [Characteristics Evaluation] <Evaluation of Initial Adhesion Strength> After production, the flexographic printing plates of Example A and Comparative Example A were quickly cut into 1 cm wide strips, and the support was forcibly peeled off. Using a tensile tester Autograph AGS-X100N (manufactured by Shimadzu Corporation), the tensile strength when the support and the photosensitive resin composition layer were peeled off in a 180° direction at a crosshead speed of 50 mm / min was measured, and the average value of the obtained peel forces was taken as the initial adhesion strength. Based on the results, the adhesive strength was evaluated according to the following criteria. A value of D or higher was considered to be within the range where there are no problems in use. The evaluation results are shown in Tables 4 and 5 below. A: The average peel force was 1.5 kgf / cm or more. B: The average peel force was 1.0 kgf / cm or more but less than 1.5 kgf / cm. C: The average peel force was 0.8 kgf / cm or more but less than 1.0 kgf / cm. D: The average peel force was 0.6 kgf / cm or more but less than 0.8 kgf / cm. E: The average peel force is less than 0.6 kgf / cm.

[0158] <Evaluation of Change in Adhesion Strength After One Month of Aging> The flexographic printing plates obtained in Example A and Comparative Example A were stored for one month in a thermo-hygrostat PH-3K (manufactured by ESPEC) set at a temperature of 40°C and a relative humidity of 80% RH. The flexographic printing plates were then cut into 1 cm wide strips, the support was forcibly peeled off, and the tensile strength when the support and the photosensitive resin composition layer were peeled off in a 180° direction at a crosshead speed of 50 mm / min using a tensile tester Autograph AGS-X100N (manufactured by Shimadzu Corporation) was measured. The average value of the resulting peel forces was taken as the adhesive strength after one month of aging. Next, the change in adhesive strength after one month of aging was calculated by subtracting the adhesive strength after one month of aging from the initial adhesive strength. Evaluation was performed according to the following criteria. A grade of C or higher was considered to be within the acceptable range for use. The evaluation results are shown in Tables 4 and 5 below. A: [(initial adhesive strength) - (adhesive strength after 1 month)] is less than 0.15 kgf / cm. C: [(initial adhesive strength) - (adhesive strength after 1 month)] is 0.15 kgf / cm or more and less than 0.30 kgf / cm. E: [(initial adhesive strength) - (adhesive strength after 1 month)] is 0.30 kgf / cm or more.

[0159]

[0160]

[0161]

[0162] [Production of Support for Flexographic Printing Plate: Example B and Comparative Example B] Supports for flexographic printing plate were produced using the substrates and adhesive coating liquids described below.

[0163] (Preparation of Substrate) A polyester film having an undercoat layer was used as the substrate constituting the support. The polyester film having an undercoat layer was prepared by subjecting 93 g of ethylene glycol, 374 g of neopentyl glycol, and 382 g of phthalic acid to a reaction at 180° C. in an air atmosphere at a concentration of 1.33×10 ３After a condensation reaction was carried out for 6 hours under a reduced pressure of 100 Pa, 125 g of 4,4-diphenylenediisocyanate was added and the reaction was continued for an additional 5 hours at 80°C to obtain a resin. The obtained resin was made into a 10% aqueous solution and applied to a melt-extruded polyethylene terephthalate film. After application, the film was biaxially stretched to obtain a polyester film having an undercoat layer. The thickness of the obtained undercoat layer was 0.05 µm.

[0164] (Preparation of reactive acrylic resin used in adhesive layer constituting support) <Reactive acrylic resin b1> Step (1): 823.5 parts of methyl methacrylate, 337.5 parts of ethyl acrylate, 90 parts of methacrylic acid, 6.75 parts of n-dodecyl mercaptan, and 7.95 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) were placed in a container and dissolved in advance at a temperature of 40°C or less (hereinafter, this solution is referred to as "mixed solution A"). Then, 3,375 parts of water and 14 parts of polyvinyl alcohol as a dispersant were added to a four-necked, round-bottomed, 5-L glass flask equipped with a stirrer and dissolved. While stirring at 400 rpm with a stirring blade, the pre-dissolved mixed solution A was added all at once to prepare a suspension. Next, with continued stirring, the reaction system of this suspension was heated to 65°C and allowed to react (suspension polymerization) for 3 hours while maintaining the temperature constant. The mixture was then heated to 90°C and allowed to react (suspension polymerization) for 1 hour while maintaining the temperature constant. The mixture was then cooled to room temperature (approximately 25°C). The reaction product was then subjected to solid-liquid separation, thoroughly washed with water, and dried at 40°C for 24 hours using a dryer. After drying, a powdery carboxyl group-containing acrylic resin was obtained at room temperature. Step (2): Next, 600 parts of water and 2 parts of polyvinyl alcohol as a dispersant were added to a 1-L four-necked round-bottom glass flask equipped with a stirrer and dissolved. While stirring at 400 rpm with a stirring blade, 200 parts of the carboxyl group-containing acrylic resin obtained in step (1) was added and dispersed. Furthermore, 2 parts of 2-methylimidazole were added and mixed as an amine compound. The reaction system of this mixture was then heated to 50°C while continuing to stir, and the temperature was maintained constant for 1 hour. Next, 20.0 parts of methacrylic acid glycidyl ester was added, and the reaction system was heated to 50°C and kept at a constant temperature for 1 hour while the mixture was impregnated with methacrylic acid glycidyl ester, and homogenization of the reaction system was attempted. The temperature was then raised to 90°C and the reaction was carried out while keeping the temperature constant for 3 hours. The reaction mixture was then cooled to room temperature (approximately 25°C). The reaction product was then subjected to solid-liquid separation, thoroughly washed with water, and dried at 40°C for 24 hours using a dryer to obtain a powdered reactive acrylic resin.Next, the obtained powdery reactive acrylic resin was mixed with a mixed monomer consisting of isobornyl acrylate and 4-hydroxybutyl acrylate (isobornyl acrylate / 4-hydroxybutyl acrylate=1 / 1) to obtain a monomer dilution of reactive acrylic resin b1 (resin concentration 40% by mass).

[0165] <Reactive acrylic resin b2> A monomer dilution of reactive acrylic resin b2 (resin concentration 40% by mass) was prepared in the same manner as for the reactive acrylic resin b1 described above, except that the amount of 2,2′-azobis(2,4-dimethylvaleronitrile) added in the step (1) was changed to 7.5 parts and the amount of methacrylic acid glycidyl ester added in the step (2) was changed to 18.0 parts.

[0166] <Reactive acrylic resin b3> A monomer dilution of reactive acrylic resin b3 (resin concentration 40% by mass) was prepared in the same manner as for the reactive acrylic resin b1 described above, except that the amount of methacrylic acid added in the step (1) was changed to 189.0 parts, the amount of 2,2′-azobis(2,4-dimethylvaleronitrile) added to 8.23 ​​parts, and the amount of methacrylic acid glycidyl ester added in the step (2) was changed to 40.0 parts.

[0167] <Reactive acrylic resin b4> A monomer dilution of reactive acrylic resin b4 (resin concentration 40% by mass) was prepared in the same manner as for the reactive acrylic resin b1 described above, except that the amount of methacrylic acid added in the step (1) was changed to 189.0 parts and the amount of methacrylic acid glycidyl ester added in the step (2) was changed to 44.0 parts.

[0168] <Reactive acrylic resin b5> A monomer dilution of reactive acrylic resin b5 (resin concentration 40% by mass) was prepared in the same manner as for the reactive acrylic resin b1 described above, except that the amount of 2,2′-azobis(2,4-dimethylvaleronitrile) added in the step (1) was changed to 5.75 parts, the amount of 2-methylimidazole added in the step (2) was changed to 1.40 parts, and the amount of methacrylic acid glycidyl ester added was changed to 15.0 parts.

[0169] <Reactive Acrylic Resin b6> Step (1): 823.5 parts of methyl methacrylate, 337.5 parts of ethyl acrylate, 70 parts of methacrylic acid, 6.75 parts of n-dodecyl mercaptan, and 5.10 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) were placed in a container and dissolved in advance at a temperature of 40°C or less (hereinafter, this solution is referred to as "mixed solution B"). Then, 3,375 parts of water and 14 parts of polyvinyl alcohol as a dispersant were added to a four-necked, round-bottomed, 5-L glass flask equipped with a stirrer and dissolved. While stirring at 400 rpm with a stirring blade, the pre-dissolved mixed solution B was added all at once to prepare a suspension. Next, with continued stirring, the reaction system of this suspension was heated to 65°C and allowed to react (suspension polymerization) for 3 hours while maintaining the temperature constant. The mixture was then heated to 90°C and allowed to react (suspension polymerization) for 1 hour while maintaining the temperature constant. The mixture was then cooled to room temperature (approximately 25°C). The reaction product was then subjected to solid-liquid separation, thoroughly washed with water, and dried at 40°C for 24 hours using a dryer. After drying, a powdery carboxyl-containing acrylic resin was obtained at room temperature. Step (2): Next, 600 parts of water and 2 parts of polyvinyl alcohol as a dispersant were added to a 1-L four-necked round-bottom glass flask equipped with a stirrer and dissolved. While stirring at 400 rpm with a stirring blade, 200 parts of the carboxyl-containing acrylic resin obtained in step (1) was added and dispersed. Furthermore, 1 part of 2-methylimidazole was added and mixed as an amine compound. The reaction system of this mixture was then heated to 50°C while continuing to stir, and the temperature was maintained constant for 1 hour. Next, 12.0 parts of methacrylic acid glycidyl ester was added, and the reaction system was heated to 50°C and kept at a constant temperature for 1 hour while the mixture was impregnated with methacrylic acid glycidyl ester, and homogenization of the reaction system was attempted. The temperature was then raised to 90°C and the reaction was carried out while keeping the temperature constant for 3 hours. The reaction mixture was then cooled to room temperature (approximately 25°C). The reaction product was then subjected to solid-liquid separation, thoroughly washed with water, and dried at 40°C for 24 hours using a dryer to obtain a powdered reactive acrylic resin.Next, the obtained powdery reactive acrylic resin was mixed with a mixed monomer consisting of isobornyl acrylate and 4-hydroxybutyl acrylate (isobornyl acrylate / 4-hydroxybutyl acrylate=1 / 1) and toluene (mixed monomer / toluene=5 / 1) to obtain a diluted reactive acrylic resin b6 (resin concentration 40% by mass).

[0170] <Reactive Acrylic Resin b7> Step (1): 823.5 parts of methyl methacrylate, 337.5 parts of ethyl acrylate, 28.4 parts of methacrylic acid, 6.75 parts of n-dodecyl mercaptan, and 4.65 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) were placed in a container and dissolved in advance at a temperature of 40°C or less (hereinafter, this solution is referred to as "mixed solution C"). Then, 3,375 parts of water and 14 parts of polyvinyl alcohol as a dispersant were added to a four-necked, round-bottomed, 5-L glass flask equipped with a stirrer and dissolved. While stirring at 400 rpm with a stirring blade, the pre-dissolved mixed solution C was added all at once to prepare a suspension. Next, with continued stirring, the reaction system of this suspension was heated to 65°C and allowed to react (suspension polymerization) for 3 hours while maintaining the temperature constant. The mixture was then heated to 90°C and allowed to react (suspension polymerization) for 1 hour while maintaining the temperature constant. The mixture was then cooled to room temperature (approximately 25°C). The reaction product was then subjected to solid-liquid separation, thoroughly washed with water, and dried at 40°C for 24 hours using a dryer. After drying, a powdery carboxyl-containing acrylic resin was obtained at room temperature. Step (2): Next, 600 parts of water and 2 parts of polyvinyl alcohol as a dispersant were added to a 1-L four-necked round-bottom glass flask equipped with a stirrer and dissolved. While stirring at 400 rpm with a stirring blade, 200 parts of the carboxyl-containing acrylic resin obtained in step (1) was added and dispersed. Furthermore, 1 part of 2-methylimidazole was added and mixed as an amine compound. The reaction system of this mixture was then heated to 50°C while continuing to stir, and the temperature was maintained constant for 1 hour. Next, 5.5 parts of methacrylic acid glycidyl ester was added, and the reaction system was heated to 50°C and kept at a constant temperature for 1 hour while the mixture was impregnated with methacrylic acid glycidyl ester, and homogenization of the reaction system was attempted. The temperature was then raised to 90°C and the reaction was carried out while keeping the temperature constant for 3 hours. The reaction mixture was then cooled to room temperature (approximately 25°C). The reaction product was then subjected to solid-liquid separation, thoroughly washed with water, and dried at 40°C for 24 hours using a dryer to obtain a powdered reactive acrylic resin.Next, the obtained powdery reactive acrylic resin was mixed with a mixed monomer consisting of isobornyl acrylate and 4-hydroxybutyl acrylate (isobornyl acrylate / 4-hydroxybutyl acrylate=1 / 1) and toluene (mixed monomer / toluene=2 / 1) to obtain a diluted reactive acrylic resin b7 (resin concentration 40% by mass).

[0171] (Preparation of Support) <Example B1> 41.4 parts by mass of bisphenol A diglycidyl ether methacrylic acid adduct, 13.4 parts by mass of reactive acrylic resin b1 monomer dilution (resin concentration 40% by mass), 32.6 parts by mass of 1,9-nonanediol diacrylate, 11.0 parts by mass of 1,6-hexanediol dimethacrylate, 1.5 parts by mass of 2,2-dimethoxy-2-phenylacetophenone, 0.4 parts by mass of 2-methyl-4,6-bis[(octylthio)methyl]-phenol were added and mixed for 2 hours to prepare an adhesive coating liquid. Next, on a polyester film (substrate) having an undercoat layer, using a bar coater, the adhesive coating liquid was applied to a coating thickness of 8 μm, and a pure polyester film was laminated thereon, and then, using an "AFP-1216" exposure machine, 30 mJ / cm from the pure polyester film side. ２ The exposure intensity was measured using a UV illuminance meter "MO-2 type" (trademark) manufactured by Oak Manufacturing Co., Ltd., with a UV-35 filter.

[0172] Examples B2 to B9, Comparative Examples B1 to B4 An adhesive coating liquid was obtained in the same manner as in Example B1, except that the composition of the adhesive layer was changed as shown in Tables 6 and 7 below, and then coated onto a substrate in the same manner as in Example B1, thereby obtaining a support in Examples B2 to B9 and Comparative Examples B1 to B4.

[0173] <Example B10> 41.4 parts by weight of bisphenol A diglycidyl ether methacrylic acid adduct, 13.4 parts by weight of diluted reactive acrylic resin b6 (resin concentration 40% by weight), 32.6 parts by weight of 1,9-nonanediol diacrylate, 11.0 parts by weight of 1,6-hexanediol dimethacrylate, 1.5 parts by weight of 2,2-dimethoxy-2-phenylacetophenone, 0.4 parts by weight of 2-methyl-4,6-bis[(octylthio)methyl]-phenol were added and mixed for 2 hours to prepare an adhesive coating liquid. Next, on a polyester film (substrate) having an undercoat layer, using a bar coater, the adhesive coating liquid was applied to a coating thickness of 8 μm, dried at 90 ° C. for 1 minute, and a solid polyester film was laminated thereon, and then, using an "AFP-1216" exposure machine, 30 mJ / cm from the solid polyester film side. ２ The exposure intensity was measured using a UV illuminance meter "MO-2 type" (trademark) manufactured by Oak Manufacturing Co., Ltd., with a UV-35 filter.

[0174] Example B11 A support was obtained in the same manner as in Example B10, except that 13.4 parts by mass of a diluted reactive acrylic resin b7 (resin concentration 40% by mass) was used instead of the diluted reactive acrylic resin b6 (resin concentration 40% by mass) of Example B10.

[0175] <Comparative Example B5> 27.3 parts by mass of bisphenol A diglycidyl ether methacrylic acid adduct, 26.3 parts by mass of styrene-butadiene-styrene copolymer polymer [T-412: manufactured by Asahi Kasei Corporation], 17.5 parts by mass of toluene, 26.3 parts by mass of 1,9-nonanediol dimethacrylate, 1.9 parts by mass of 2,2-dimethoxy-2-phenylacetophenone, and 0.7 parts by mass of 2-methyl-4,6-bis[(octylthio)methyl]-phenol were added and mixed for 2 hours to prepare an adhesive coating liquid. Next, using a bar coater, the adhesive coating liquid was applied to a polyester film (substrate) having an undercoat layer so that the coating thickness was 20 μm, and the resulting mixture was dried at 90 ° C. for 1 minute. A pure polyester film was then laminated thereon, and then, using an "AFP-1216" exposure machine, 50 mJ / cm from the pure polyester film side was applied. ２The exposure intensity was measured using a UV illuminance meter "MO-2 type" (trademark) manufactured by Oak Manufacturing Co., Ltd., with a UV-35 filter.

[0176] The properties of UH-2000, UF-3003, and T-412 in Table 8 are as follows: UH-2000: Acrylic polymer manufactured by Toagosei Co., Ltd. UF-3003: Polyester urethane acrylate manufactured by Kyoeisha Chemical Co., Ltd. T-412: Styrene thermoplastic elastomer manufactured by Asahi Kasei Corporation

[0177] [Measurement of physical properties] <Method for measuring double bond equivalent> The double bond equivalent of reactive acrylic resins b1 to b7 was calculated from the amount of double bonds in the sample, which was quantified based on the iodine value measured by the method of JIS K0070 (established in 1992), and the mass or molecular weight of the sample. The measurement results of the double bond equivalent of the reactive acrylic resins are shown in Table 6.

[0178] <Weight-average molecular weight (Mw) by gel permeation column chromatography (GPC)> [1. Sample preparation] 10 g of tetrahydrofuran was added to 0.5 g of the measurement target, and the mixture was left to dissolve for 2 hours while applying ultrasound. The mixture was then filtered through a polytetrafluoroethylene membrane filter (pore size 3 μm, manufactured by ADVANTEC), and the filtrate was used as the measurement sample. [2. Apparatus and measurement conditions] GPC measurement of a liquid reactive acrylic resin was carried out using the following apparatus and measurement conditions. Note that because the reactive acrylic resin was diluted with monomer, the resulting GPC chart had multiple peaks, but the peak with the largest weight-average molecular weight was taken as the peak corresponding to the reactive acrylic resin. Apparatus: HLC-8220 manufactured by Tosoh Corporation. GPC column: Separation was performed using four of the following columns connected in series. TSKgel GMH XL manufactured by Tosoh TSKgel GMH XL manufactured by Tosoh TSKgel GMH XLL manufactured by Tosoh TSKgel GMH XLL manufactured by Tosoh Column temperature: 40°C Solvent: tetrahydrofuran Flow rate: 1 mL / min Detector: RI Calibration curve: standard polystyrene The measurement results of the weight average molecular weight of the reactive acrylic resin are shown in Table 6.

[0179]

[0180] [Characteristics Evaluation] <Evaluation of Initial Adhesion Strength> Using the supports obtained in Example B and Comparative Example B, samples for evaluating adhesion strength were produced by the following method.

[0181] [Preparation of Photosensitive Resin Composition] A photosensitive resin composition was prepared by kneading 60 parts by mass of Tufprene A (styrene-butadiene-styrene block copolymer, manufactured by Asahi Kasei Corporation), 30 parts by mass of B-2000 (liquid polybutadiene, manufactured by Nippon Petrochemical Industries, Ltd.), 7 parts by mass of 1,9-nonanediol diacrylate, 2 parts by mass of 2,2-dimethoxy-2-phenylacetophenone, and 0.3 parts by mass of 2,6-di-t-butyl-p-cresol in a pressure kneader.

[0182] [Production of Laminate of Support and Photosensitive Resin Composition] The above-mentioned photosensitive resin composition was charged into an extrusion molding machine, and a support having an adhesive layer was laminated to one side of the photosensitive resin composition layer extruded from a T-shaped die. A release film (Diafoil MRV100, manufactured by Mitsubishi Chemical Corporation) was laminated to the side of the photosensitive resin composition layer opposite to the support laminated side, thereby obtaining a laminate of the support and the photosensitive resin composition layer.

[0183] [Method for manufacturing a sample for evaluating adhesive strength, and method for evaluating adhesive strength] The laminate of the support and the photosensitive resin composition layer prepared as described above was exposed from the support side using an "AFP-1216" exposure machine so that the pattern height (RD) after curing would be about 0.7 mm. Next, the exposure machine was used to expose the laminate from the release film side at 8000 mJ / cm ２ Next, the release film was peeled off, and development was carried out using Sorbitol (trademark, manufactured by MacDermid, a mixed organic solvent of 60% by mass of hydrocarbons and 40% by mass of aliphatic alcohol, boiling point 155 to 205°C) as a developer, using an "AFP-1321P" developing machine (trademark, manufactured by Asahi Kasei Corporation) at a liquid temperature of 30°C and a speed of 135 mm / min, and then drying at 60°C for 2 hours. Thereafter, as a post-processing exposure, a germicidal lamp having a central wavelength of 254 nm was used to irradiate the entire plate surface with 2000 mJ / cm ２ , followed by 1000 mJ / cm using a UV fluorescent lamp. ２The film was then exposed to light for 10 seconds to obtain a sample for evaluating adhesion strength. The film was then quickly cut into 1 cm wide strips, and the support was forcibly peeled off. Using a tensile tester Autograph AGS-X100N (manufactured by Shimadzu Corporation), the tensile strength was measured when the support and the photosensitive resin composition layer were peeled off in a 180° direction at a crosshead speed of 50 mm / min, and the average value of the resulting peel strength was taken as the initial adhesion strength. Evaluation was based on the following criteria. A grade of D or higher was considered to be within the acceptable range for use. The evaluation results are shown in Tables 7 and 8. A: The average peel strength was 1.5 kgf / cm or higher. B: The average peel strength was 1.0 kgf / cm or higher but less than 1.5 kgf / cm. C: The average peel strength was 0.8 kgf / cm or higher but less than 1.0 kgf / cm. D: The average peel strength was 0.6 kgf / cm or higher but less than 0.8 kgf / cm. E: The average peel strength was less than 0.6 kgf / cm.

[0184] <Evaluation of Adhesion Strength Change After One Month> The adhesive strength evaluation sample prepared as described above was stored for one month in a thermo-hygrostat PH-3K (manufactured by ESPEC Corporation) set at a temperature of 40°C and a relative humidity of 80% RH. The adhesive strength evaluation sample was then cut into 1 cm wide strips, the support was forcibly peeled off, and the support and the photosensitive resin composition layer were peeled off in a 180° direction at a crosshead speed of 50 mm / min using a tensile tester Autograph AGS-X100N (manufactured by Shimadzu Corporation). The tensile strength was measured when the support and the photosensitive resin composition layer were peeled off, and the average value of the resulting peel strength was taken as the adhesive strength after one month. Next, the adhesive strength change after one month was calculated by subtracting the adhesive strength after one month from the initial adhesive strength. Evaluation was performed according to the following criteria. A grade of C or higher was considered to be within the acceptable range for use. The evaluation results are shown in Tables 7 and 8 below. A: [(initial adhesive strength) - (adhesive strength after 1 month)] is less than 0.15 kgf / cm. C: [(initial adhesive strength) - (adhesive strength after 1 month)] is 0.15 kgf / cm or more and less than 0.30 kgf / cm. E: [(initial adhesive strength) - (adhesive strength after 1 month)] is 0.30 kgf / cm or more.

[0185] <Evaluation of Volatile Component Amount> 100 g of the adhesive layer coating liquid prepared in the Examples and Comparative Examples was collected into a beaker, and then the beaker was immediately placed in a draft chamber (manufactured by DALTON) with an airflow of 0.45 m / s, with the beaker left open for 12 hours. The mass of the adhesive coating liquid was then measured, and the amount of mass change before and after collecting the coating liquid was measured. Based on the results, evaluation was performed according to the following criteria. A was determined to be within a range that was acceptable for use. The evaluation results are shown in Tables 7 and 8. A: The amount of change in the adhesive coating liquid was less than 1.0 g. B: The amount of change in the adhesive coating liquid was 1.0 g or more but less than 2.0 g. C: The amount of change in the adhesive coating liquid was 2.0 g or more but less than 3.0 g. E: The amount of change in the adhesive coating liquid was 3.0 g or more.

[0186] <Evaluation of cure shrinkage> The substrates having adhesive layers prepared in the examples and comparative examples were exposed to 200 mJ / cm 2 from the release film side using an "AFP-1216" exposure machine. ２ The film was exposed to light for 10 seconds. The exposure intensity was measured using a UV-35 filter with a UV illuminance meter "MO-2 Model" (trademark) manufactured by Oak Manufacturing Co., Ltd. Five exposed supports were prepared for each Example and Comparative Example. The supports were bent 10 times, and the cure shrinkage of the coating liquid was evaluated based on the number of films that developed cracks or peeling of the adhesive layer. Based on the results, evaluation was performed according to the following criteria. A rating of D or higher was considered to be within the range where there are no problems in use. The evaluation results are shown in Tables 7 and 8. A: No cracks occurred in any film, and no peeling of the adhesive layer occurred. B: One or two cracks occurred in any film, and no peeling of the adhesive layer occurred. C: Three or four cracks occurred in any film, and no peeling of the adhesive layer occurred. D: Five cracks occurred in any film, and no peeling of the adhesive layer occurred. E: Peeling of the adhesive layer occurred.

[0187]

[0188]

[0189] This application is based on Japanese patent applications (Patent Application Nos. 2024-055730 and 2024-055664) filed with the Japan Patent Office on March 29, 2024, the contents of which are incorporated herein by reference.

[0190] The flexographic printing plate precursor and support of the present invention have industrial applicability in the field of flexographic printing plate manufacturing.

[0191] (a) Support (b) Photosensitive resin composition layer (b') Printing pattern (c) Adhesive layer (d) Infrared ablation layer (d') Mask for infrared ablation layer (f) Base material

Claims

1. A flexographic printing original plate comprising at least a support (a) having a substrate (f) and an adhesive layer (c), and a photosensitive resin composition layer (b) laminated together, wherein the adhesive layer (c) contains a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule.

2. A flexographic printing original plate according to claim 1, comprising at least a support (a) having a substrate (f) and an adhesive layer (c), and a photosensitive resin composition layer (b) laminated together, wherein the adhesive layer (c) contains 3% by mass to 30% by mass of a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule, and satisfies the following <Condition (1)>: <Condition (1)> 600 mJ / cm from the support (a) side. ２ , 8000 mJ / cm from the photosensitive resin composition layer (b) side ２ When a cross section of the cured product obtained by irradiating the adhesive layer with ultraviolet light is measured by AFM (Atomic Force Microscopy) force curve, the amount of deformation of the adhesive layer (c) is 20 nm or less.

3. The flexographic printing plate precursor according to claim 1, wherein the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule has a double bond equivalent of 1,500 or more and 5,000 or less.

4. The flexographic printing plate precursor according to claim 1, wherein the weight average molecular weight (Mw) of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule is 20,000 or more and 40,000 or less.

5. The flexographic printing plate precursor according to claim 1, wherein the adhesive layer (c) further contains a bifunctional or higher functional (meth)acrylate compound having one or more aromatic rings and / or one or more hydroxyl groups in the molecule.

6. A method for producing a flexographic printing plate using the flexographic printing original plate according to any one of claims 1 to 5, comprising: a first step of irradiating ultraviolet light from the support (a) side; a second step of placing a negative film on the photosensitive resin composition layer (b) or laser ablating an infrared ablation layer (d) provided on the photosensitive resin composition layer (b) to produce a negative pattern; a third step of irradiating the photosensitive resin composition layer (b) with ultraviolet light through the negative film or using the infrared ablation layer (d) on which the negative pattern has been drawn and processed as a mask to perform pattern exposure; and a fourth step of removing unexposed areas of the photosensitive resin composition layer (b).

7. A flexographic printing method comprising: producing a flexographic printing plate by the method for producing a flexographic printing plate according to claim 6; an ink applying step of applying ink to the raised portions of the flexographic printing plate; and a transfer step of transferring the ink to a substrate.

8. A support (a) for a flexographic printing original plate having a substrate (f) and an adhesive layer (c), wherein the adhesive layer (c) contains a reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule.

9. The support (a) according to claim 8, wherein the adhesive layer (c) contains 3% by mass or more and 30% by mass or less of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule.

10. The support (a) according to claim 8, wherein the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule has a double bond equivalent of 1,500 or more and 5,000 or less.

11. The support (a) according to claim 8, wherein the weight average molecular weight (Mw) of the reactive acrylic resin (c-1) having three or more (meth)acryloyl groups in the molecule is 14,000 or more and 60,000 or less.

12. The support (a) according to claim 8, wherein the adhesive layer (c) contains a bifunctional or higher functional (meth)acrylate compound having one or more aromatic rings and / or one or more hydroxyl groups in the molecule.

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