Aqueous developer for flexographic printing plate, aqueous developer concentrate for flexographic printing plate, and method for producing flexographic printing plate

Abstract

The present invention aims to provide an aqueous developer for flexographic printing plates having excellent concentration suitability and good storage stability as a concentrated solution, an aqueous developer concentrate for flexographic printing plates, and a method for producing flexographic printing plates using the same. The aqueous developer for flexographic printing plates of the present invention is an aqueous developer for flexographic printing plates containing an anionic surfactant, a nonionic surfactant, and water, wherein the anionic surfactant is a compound represented by the following formula (1). Here, in the following formula (1), R 1 represents an optionally substituted alkyl group having 3 to 20 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, or an alkynyl group having 3 to 20 carbon atoms. 1 represents a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a sulfuric acid group or a salt thereof, or a phosphoric acid group or a salt thereof. 1 ‑X 1 ……(1).

Description

Technical Field

[0001] The present invention relates to an aqueous developer for flexographic printing plates, an aqueous developer concentrate for flexographic printing plates, and a method for producing a flexographic printing plate using the same. Background Art

[0002] In recent years, there has been a trend across various industries to reduce the use of organic solvents from the perspective of improving the working environment and preserving the global environment. Consequently, the use of aqueous-developable photosensitive resin plates in the platemaking process of photosensitive flexographic printing plates for printing has also been increasing.

[0003] For example, Patent Document 1 describes “a developer composition for a printing plate, comprising (a) an alkali metal salt of a saturated fatty acid having 12 to 18 carbon atoms and (b) an alkali metal salt of an unsaturated fatty acid having 12 to 18 carbon atoms in a weight ratio of (a):(b) = 20:80 to 80:20” ([Claim 1]).

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2012 / 111238 Summary of the Invention

[0007] Technical issues to be solved by the invention

[0008] Regarding the aqueous developer described in Patent Document 1, etc., the present inventors have studied the form of concentrated solution from the perspective of reducing the volume during storage and transportation. The results show that depending on the type of surfactant contained in the aqueous developer, the solubility or dispersibility of the surfactant may be reduced when it is concentrated, resulting in poor concentration suitability. In addition, even if the solubility of the surfactant is good when it is concentrated, precipitation of the surfactant may occur over time, resulting in poor storage stability.

[0009] Therefore, an object of the present invention is to provide an aqueous developer for flexographic printing plates having excellent concentration suitability and good storage stability as a concentrated solution, an aqueous developer concentrate for flexographic printing plates, and a method for producing a flexographic printing plate using the same.

[0010] Means for solving technical problems

[0011] The present inventors have conducted intensive studies to achieve the above-mentioned objectives and have found that an aqueous developer containing a nonionic surfactant together with a predetermined anionic surfactant has excellent concentration suitability and good storage stability as a concentrated solution, thereby completing the present invention.

[0012] That is, the present inventors have found that the above-mentioned objects can be achieved by the following configuration.

[0013] [1] A water-based developer for flexographic printing plates, comprising an anionic surfactant, a nonionic surfactant, and water,

[0014] The anionic surfactant is a compound represented by the following formula (1).

[0015] R 1 -X 1 ……(1)

[0016] Here, in the following formula (1),

[0017] R 1 It represents an alkyl group having 3 to 20 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, or an alkynyl group having 3 to 20 carbon atoms, which may have a substituent.

[0018] X1 表 represents a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a sulfuric acid group or a salt thereof, or a phosphoric acid group or a salt thereof.

[0019] [2] The aqueous developer for flexographic printing plates according to [1], wherein

[0020] The content of the anionic surfactant is 0.01 to 10% by mass, and the content of the nonionic surfactant is 0.01 to 10% by mass.

[0021] [3] The aqueous developer for flexographic printing plates according to [1] or [2], further comprising an alkali agent.

[0022] [4] The aqueous developer for flexographic printing plates according to any one of [1] to [3], wherein

[0023] R in the above formula (1) 1 The number of carbon atoms is 6 to 14.

[0024] [5] The aqueous developer for flexographic printing plates according to any one of [1] to [4], wherein

[0025] The compound represented by the above formula (1) has an HLB value of 8 or less and is water-soluble.

[0026] [6] The aqueous developer for flexographic printing plates according to any one of [1] to [5], wherein

[0027] The nonionic surfactant is a compound represented by the following formula (2).

[0028] [Chemical Formula 1]

[0029]

[0030] Here, in the above formula (2),

[0031] Ar represents an m-valent aromatic group, and m represents an integer of 1 to 8.

[0032] X 2 represents a monovalent organic group, and p represents an integer of 0 to 3. Wherein, p < m, when p is 2 or 3, multiple X 2 They may be the same as or different from each other.

[0033] A represents an alkylene group having 2 to 4 carbon atoms, R 2 represents a hydrogen atom or an alkyl group, and n represents an integer from 1 to 100. When n is an integer from 2 to 100, multiple A's may be the same or different. When mp is an integer from 2 to 8, multiple A's, n's and R's may be the same or different. 2 They may be the same as or different from each other.

[0034] [7] A method for manufacturing a flexographic printing plate, the flexographic printing plate having a non-image portion and an image portion, the method comprising:

[0035] An exposure step of exposing the photosensitive layer of the flexographic printing plate precursor having the photosensitive layer in the form of an image;

[0036] a developing step, after the exposure step, developing the flexographic printing plate using the aqueous developer described in any one of [1] to [6] to form a non-image area and an image area; and

[0037] The rinsing process is performed after the development process using water.

[0038] [8] A concentrated aqueous developer for flexographic printing plates, comprising an anionic surfactant, a nonionic surfactant, and water.

[0039] [9] The aqueous developer concentrate for flexographic printing plates according to [8], wherein

[0040] The content of the anionic surfactant is 0.02 to 40% by mass, and the content of the nonionic surfactant is 0.02 to 40% by mass.

[0041]

[10] The aqueous developer concentrate for flexographic printing plates according to [8] or [9], further comprising an alkali agent.

[0042]

[11] The aqueous developer concentrate for flexographic printing plates according to any one of [8] to

[10] , wherein the anionic surfactant is a compound represented by the following formula (1).

[0043] R 1 -X1 ……(1)

[0044] Here, in the following formula (1),

[0045] R 1 It represents an alkyl group having 3 to 20 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, or an alkynyl group having 3 to 20 carbon atoms, which may have a substituent.

[0046] X 1 It represents a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a sulfuric acid group or a salt thereof, or a phosphoric acid group or a salt thereof.

[0047]

[12] The aqueous developer concentrate for flexographic printing plates according to

[11] , wherein:

[0048] R in the above formula (1) 1 The number of carbon atoms is 6 to 14.

[0049]

[13] The aqueous developer concentrate for flexographic printing plates according to

[11] or

[12] , wherein:

[0050] The compound represented by the above formula (1) has an HLB value of 8 or less and is water-soluble.

[0051]

[14] The aqueous developer concentrate for flexographic printing plates according to any one of [8] to

[13] , wherein

[0052] The nonionic surfactant is a compound represented by the following formula (2).

[0053] [Chemical Formula 2]

[0054]

[0055] Here, in the above formula (2),

[0056] Ar represents an m-valent aromatic group, and m represents an integer of 1 to 8.

[0057] X 2 represents a monovalent organic group, and p represents an integer of 0 to 3. Wherein, p < m, when p is 2 or 3, multiple X 2 They may be the same as or different from each other.

[0058] A represents an alkylene group having 2 to 4 carbon atoms, R 2 represents a hydrogen atom or an alkyl group, and n represents an integer from 1 to 100. When n is an integer from 2 to 100, multiple A's may be the same or different. When mp is an integer from 2 to 8, multiple A's, n's and R's may be the same or different. 2 They may be the same as or different from each other.

[0059]

[15] A method for manufacturing a flexographic printing plate, the flexographic printing plate having a non-image portion and an image portion, the method comprising:

[0060] An exposure step of exposing the photosensitive layer of the flexographic printing plate precursor having the photosensitive layer in the form of an image;

[0061] a developing step, after the exposure step, developing the flexographic printing plate using a liquid prepared by diluting the aqueous developer concentrate described in any one of [8] to

[14] by 2 to 20 times to form a non-image area and an image area; and

[0062] The rinsing process is performed after the development process using water.

[0063] Effects of the Invention

[0064] According to the present invention, there can be provided an aqueous developer for flexographic printing plates having excellent concentration suitability and good storage stability as a concentrated solution, an aqueous developer concentrate for flexographic printing plates, and a method for producing a flexographic printing plate using the same. DETAILED DESCRIPTION

[0065] Hereinafter, the present invention will be described in detail.

[0066] The following description of the constituent elements is based on representative embodiments of the present invention, but the present invention is not limited to these embodiments.

[0067] In addition, in this specification, the numerical range expressed using "to" means a range including the numerical values described before and after "to" as the lower limit and the upper limit.

[0068] Furthermore, in this specification, each component may be used alone or in combination of two or more substances. When two or more substances are used simultaneously for each component, the content of the component refers to the total content of the substances used simultaneously, unless otherwise specified.

[0069] [Water-based developer for flexographic printing plates]

[0070] The aqueous developer for flexographic printing plates of the present invention (hereinafter also referred to simply as "the developer of the present invention") is an aqueous developer for flexographic printing plates containing an anionic surfactant, a nonionic surfactant, and water.

[0071] Furthermore, the anionic surfactant contained in the developer of the present invention is a compound represented by the formula (1) described later.

[0072] In the present invention, as described above, the aqueous developer prepared by blending a nonionic surfactant together with the anionic surfactant represented by formula (1) described later has excellent concentration suitability and good storage stability as a concentrated solution.

[0073] Although the details are not yet clear, the present inventors speculate as follows.

[0074] First, as shown in Comparative Examples 1 to 4 described later, it was found that when only anionic surfactants were added without a nonionic surfactant, the concentration suitability was poor.

[0075] Furthermore, as shown in Comparative Example 5 described later, it was found that when only a nonionic surfactant was added without adding an anionic surfactant, the storage stability as a concentrated solution was poor.

[0076] Therefore, in the present invention, by blending a nonionic surfactant together with an anionic surfactant represented by formula (1) described later, the interaction between these surfactants improves dispersibility or solubility compared to the case where each surfactant is blended alone, thereby achieving excellent concentration suitability and good storage stability as a concentrated liquid.

[0077] Hereinafter, each component contained in the developer of the present invention will be described in detail.

[0078] [Anionic surfactant]

[0079] The anionic surfactant contained in the developer of the present invention is a compound represented by the following formula (1).

[0080] R 1 -X 1 ……(1)

[0081] In the above formula (1), R 1 It represents an alkyl group having 3 to 20 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, or an alkynyl group having 3 to 20 carbon atoms, which may have a substituent.

[0082] Furthermore, in the above formula (1), X 1 It represents a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a sulfuric acid group or a salt thereof, or a phosphoric acid group or a salt thereof.

[0083] R in the above formula (1) 1 The alkyl group having 3 to 20 carbon atoms represented by one embodiment may be any of linear, branched and cyclic, and specific examples thereof include methyl, ethyl, propyl, butyl, hexyl, 2-ethylhexyl, octyl, decyl, dodecyl, hexadecyl, octadecyl, cyclohexyl and cyclooctyl.

[0084] As R in the above formula (1) 1The alkenyl group having 3 to 20 carbon atoms represented by one embodiment of the present invention may be any of linear, branched and cyclic. Specific examples thereof include 1-propenyl, 1-butenyl, 1-methyl-1-propenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl and cyclohexenyl.

[0085] As R in the above formula (1) 1 The alkynyl group having 3 to 20 carbon atoms represented by one embodiment of can be any of linear, branched, and cyclic. Specific examples thereof include 1-propynyl, 1-butynyl, 1-octynyl, 1-decynyl, and 1-octadecyl.

[0086] Furthermore, as R in the above formula (1) 1 The substituents that can be used may be monovalent non-metallic atomic groups other than hydrogen atoms, for example, halogen atoms (F, Cl, Br or I), hydroxyl groups, alkoxy groups, aryloxy groups, acyl groups, amide groups, ester groups, acyloxy groups, carboxyl groups, carboxylic acid anion groups and sulfonic acid anion groups.

[0087] Specific examples of the alkoxy group include methoxy, ethoxy, propoxy, isopropoxy, butoxy, pentyloxy, hexyloxy, dodecyloxy, stearyloxy, methoxyethoxy, poly(ethyleneoxy) group, poly(propyleneoxy) group, and the like, preferably having 1 to 40 carbon atoms, more preferably 1 to 20 carbon atoms.

[0088] Specific examples of the aryloxy group include aryloxy groups having 6 to 18 carbon atoms, such as phenoxy, tolyloxy, xylyloxy, mesityloxy, cumyloxy, methoxyphenoxy, ethoxyphenoxy, chlorophenoxy, bromophenoxy, and naphthyloxy.

[0089] Specific examples of the acyl group include acyl groups having 2 to 24 carbon atoms, such as acetyl, propionyl, butyryl, benzoyl, and naphthoyl.

[0090] Specific examples of the amide group include amide groups having 2 to 24 carbon atoms, such as acetamide, propionic acid amide, dodecanoic acid amide, palmitic acid amide, stearic acid amide, benzoic acid amide, and naphthoic acid amide.

[0091] Specific examples of the acyloxy group include acyloxy groups having 2 to 20 carbon atoms, such as an acetyloxy group, a propionyloxy group, a benzoyloxy group, and a naphthoyloxy group.

[0092] Specific examples of the ester group include ester groups having 1 to 24 carbon atoms, such as a methyl ester group, an ethyl ester group, a propyl ester group, a hexyl ester group, an octyl ester group, a dodecyl ester group, and a stearyl ester group.

[0093] The substituent may be composed of a combination of two or more of the above-mentioned substituents.

[0094] In the present invention, for the developer of the present invention, it is preferred that R in the above formula (1) is 1 The number of carbon atoms is 6 to 14. Specifically, R in the above formula (1) 1 An alkyl group having 6 to 14 carbon atoms is more preferred, and an alkyl group having 6 to 10 carbon atoms is even more preferred because aggregation of development residue (dispersion) can be suppressed during development using the developer of the present invention.

[0095] X in the above formula (1) 1 As described above, it represents a carboxylic acid group (-COOH) or a salt thereof, a sulfonic acid group (-SO3H) or a salt thereof, a sulfuric acid group (-OSO3H) or a salt thereof, or a phosphoric acid group (-OPO3H2) or a salt thereof, among which, preferably, it is a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, or a sulfuric acid group or a salt thereof, and more preferably, it is a carboxylic acid group or a salt thereof.

[0096] Furthermore, the salt of the carboxylic acid group or the like is preferably an alkali metal salt such as a sodium salt or a potassium salt.

[0097] In the present invention, the compound represented by the above formula (1) preferably has an HLB value of 8 or less and is water-soluble because the formation of a film on the liquid surface can be suppressed in the developer of the present invention.

[0098] Furthermore, it is preferred that the compound represented by the above formula (1) has an HLB value of 3 or more.

[0099] Here, the HLB (Hydrophile Lipophile Balance) value in the present invention refers to a value calculated by the following formula (HL), where M is the molecular weight of the compound represented by the above formula (1) and Mw is the molecular weight of X1 in the above formula (1).

[0100] HLB value = 20 × Mw / M……(HL)

[0101] In the present invention, "water-soluble" means that when the compound represented by the above formula (1) is dried at 105°C for 2 hours and then dissolved in 100 g of water at 40°C, no insoluble matter is observed with the naked eye within 3 hours.

[0102] In the present invention, the content of the anionic surfactant is preferably 0.01 to 10% by mass, more preferably 0.1 to 2% by mass, relative to the total mass of the developer of the present invention.

[0103] [Nonionic surfactant]

[0104] The nonionic surfactant contained in the developer of the present invention is not particularly limited, and conventionally known nonionic surfactants can be used.

[0105] Examples of the nonionic surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polystyrylphenyl ethers, glycerol fatty acid partial esters, sorbitan fatty acid partial esters, pentaerythritol fatty acid partial esters, propylene glycol monofatty acid esters, sucrose fatty acid partial esters, polyoxyethylene sorbitan fatty acid partial esters, polyoxyethylene sorbitol fatty acid partial esters, polyethylene glycol fatty acid esters, polyglycerol fatty acid partial esters, polyoxyethylene glycerol fatty acid partial esters, polyoxyethylene diglycerols, fatty acid diethanolamides, N,N-bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides, polyoxyethylene alkylphenyl ethers, and polyoxyethylene-polyoxypropylene block copolymers.

[0106] In the present invention, the nonionic surfactant is preferably a compound represented by the following formula (2) because it has better storage stability as a concentrated solution and can suppress aggregation of development residue (dispersion) during development using the developer of the present invention.

[0107] [Chemical Formula 3]

[0108]

[0109] In the above formula (2), Ar represents an m-valent aromatic group, and m represents an integer of 1 to 8.

[0110] Furthermore, in the above formula (2), X 2 represents a monovalent organic group, and p represents an integer of 0 to 3. Wherein, p < m, when p is 2 or 3, multiple X 2 can be the same as or different from each other,

[0111] Furthermore, in the above formula (2), A represents an alkylene group having 2 to 4 carbon atoms, and R 2 represents a hydrogen atom or an alkyl group, and n represents an integer from 1 to 100. When n is an integer from 2 to 100, multiple A's may be the same or different from each other. When mp is an integer from 2 to 8, multiple A's, n's and R's may be the same or different from each other. 2 They may be the same as or different from each other.

[0112] The aromatic group represented by Ar in the above formula (2) refers to a group containing an aromatic ring, and examples thereof include an m-valent group having at least one aromatic ring selected from the group consisting of aromatic hydrocarbon rings and aromatic heterocycles.

[0113] Herein, examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthroline ring, and examples of the aromatic heterocyclic ring include a furan ring, a pyrrole ring, a thiophene ring, a pyridine ring, a thiazole ring, and a benzothiazole ring.

[0114] Furthermore, the valence (m) of the aromatic group represented by Ar in the above formula (2) is an integer of 1 to 8, preferably an integer of 2 to 6, more preferably an integer of 2 to 4, and even more preferably 2 or 3.

[0115] Among them, Ar is preferably a divalent benzene ring (ie, a phenylene group) or a monovalent naphthalene ring (ie, a naphthyl group), and more preferably a phenylene group.

[0116] As X in the above formula (2) 2 Examples of the monovalent organic group include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, and an alkenyl group, and these groups may further have a substituent.

[0117] Examples of the alkyl group include linear or branched alkyl groups having 1 to 18 carbon atoms, and specific examples include methyl, ethyl, propyl, butyl, pentyl, tert-pentyl, and n-hexyl groups.

[0118] Examples of the cycloalkyl group include monocyclic or polycyclic cycloalkyl groups having 3 to 20 carbon atoms, and specific examples include cyclopentyl, cyclopentylmethyl, cyclopentylethyl, cyclohexyl, cyclohexylmethyl, and cyclohexylethyl.

[0119] Examples of the aryl group include aryl groups having 6 to 14 carbon atoms, and specific examples include phenyl, methylphenyl, tolyl, xylyl, naphthyl, anthryl, phenanthryl, and pyrenyl.

[0120] Examples of the aralkyl group include aralkyl groups having 7 to 20 carbon atoms, and specific examples include benzyl, phenethyl, 2-phenylethan-2-yl, and naphthylmethyl.

[0121] Examples of the alkenyl group include alkenyl groups having 3 to 20 carbon atoms, and specific examples include vinyl groups and allyl groups.

[0122] Among these organic groups, X in the above formula (2) is preferably 2 It is preferably an aralkyl group, and more preferably a 2-phenylethan-2-yl group or a benzyl group.

[0123] In addition, the structures of 2-phenylethane-2-yl and benzyl are shown in the following formulas (X-1) and (X-2), respectively. However, the structure represented by the following formula (X-1) (2-phenylethane-2-yl) is also referred to as "styrenated" or "styryl".

[0124] [Chemical Formula 4]

[0125]

[0126] In the above formula (2), p represents an integer of 0 to 3, but p < m. In development using the developer of the present invention, p preferably represents an integer of 1 to 3, more preferably 1 or 2, because aggregation of development residues can be suppressed.

[0127] A in the above formula (2) represents an alkylene group having 2 to 4 carbon atoms, and is preferably an alkylene group having 2 or 3 carbon atoms, and more preferably a vinyl group or an n-propylene group.

[0128] As R in the above formula (2) 2 The alkyl group represented by one embodiment of is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms. Specific examples thereof include a methyl group, an ethyl group, a propyl group, and an n-butyl group.

[0129] In addition, R in the above formula (2) 2 represents a hydrogen atom or an alkyl group, but a hydrogen atom is preferred because aggregation of development residues can be suppressed during development using the developer of the present invention.

[0130] n in the above formula (2) represents an integer of 1 to 100, and is preferably an integer of 1 to 30, more preferably an integer of 5 to 20, and even more preferably an integer of 5 to 15, because it can suppress aggregation of development residues during development using the developer of the present invention.

[0131] Specific examples of the compound (nonionic surfactant) represented by the above formula (2) include:

[0132] Polyoxyalkylene polystyrylphenyl ethers such as polyoxyethylene styrenated phenyl ether, polyoxyethylene polystyrylphenyl ether, polyoxyethylene distyrenated phenyl ether, polyoxyethylene tristyrylphenyl ether represented by the following formula (2-1), polyoxyethylene styrenated phenyl ether ammonium sulfate, and polyoxyethylene polystyrylphenyl ether condensates;

[0133] Polyoxyethylene dodecylphenyl ether, polyoxyethylene phenyl ether, polyoxyethylene benzyl ether, polyoxyethylene β-naphthyl ether, polyoxyethylene bisphenol A ether, polyoxyethylene bisphenol F ether, polyoxyethylene cumylphenyl ether, polyoxyethylene naphthyl ether, polyoxyethylene tribenzylphenyl ether, polyoxyethylene aryl ether, polyoxyethylene polycyclic phenyl ether, polyoxyalkylene polycyclic phenyl ether; etc.

[0134] [Chemical Formula 5]

[0135]

[0136] In the present invention, the content of the nonionic surfactant is preferably 0.01 to 10% by mass, more preferably 0.1 to 2% by mass, relative to the total mass of the developer of the present invention.

[0137] 〔water〕

[0138] The water contained in the developer of the present invention is not particularly limited, and any of purified water, distilled water, ion-exchanged water, pure water, and ultrapure water such as Milli-Q water can be used. In addition, Milli-Q water is ultrapure water obtained by a Milli-Q water production device, which is an ultrapure water production device of Merck KGaA.

[0139] The content of water contained in the developer of the present invention is preferably 80 to 99.99% by mass, more preferably 90 to 99.9% by mass, based on the total mass of the developer.

[0140] [Alkali]

[0141] The developer of the present invention preferably contains an alkali agent because the developing property becomes good.

[0142] Examples of the alkaline agent include alkali metal carbonates and alkali metal hydroxides.

[0143] Among them, specific examples of the alkali metal include sodium, potassium, and calcium.

[0144] Specific examples of the alkali metal carbonate include sodium carbonate and potassium carbonate. Among them, sodium carbonate is preferred from the viewpoint of safety.

[0145] Furthermore, specific examples of the alkali metal hydroxide include sodium hydroxide and potassium hydroxide.

[0146] When the alkali agent is contained, the content is preferably 0.01 to 2 mass %, more preferably 0.1 to 0.5 mass %, based on the total mass of the developer of the present invention.

[0147] 〔Chelating agent〕

[0148] The developer of the present invention preferably contains a chelating agent because aggregation of development residue can be suppressed.

[0149] Specific examples of the chelating agent include citric acid, ethylenediaminetetraacetic acid (EDTA), ethylenediamine-N,N′-disuccinic acid (EDDS), L-glutamic acid diacetic acid (GLDA), and alkali metal salts thereof.

[0150] [Other ingredients]

[0151] The developer of the present invention may contain various additives as optional components as needed.

[0152] As additives, for example, alkanolamines such as ethanolamine; preservatives such as benzotriazole and benzoic acid; freezing point depression agents such as glycols (for example, ethylene glycol, etc.) and lower alcohols (for example, ethanol, etc.); defoaming agents such as silicones and polyols; etc. can be appropriately added within the range that does not impair the effects of the present invention.

[0153] [Development Method]

[0154] Regarding the development method using the developer of the present invention, the same method as the development method using the conventionally known aqueous developer can be cited. For example, the following method can be cited, that is, the developer is brought into contact with the unexposed portion of the flexographic printing plate precursor, and physical effects such as a brush, water pressure, and ultrasound are applied to disperse the photosensitive layer (photosensitive resin composition) constituting the unexposed portion in the developer and remove it.

[0155] At this time, the developer may be used to immerse the unexposed portion, and may be continuously supplied so as to contact the unexposed portion while applying a physical action.

[0156] Furthermore, the liquid temperature of the developer during development is preferably 20 to 60°C, more preferably 30 to 50°C.

[0157] Furthermore, as a physical force commonly used, a brush is used, and the material, thickness, length, density and arrangement of the bristles, the movement and rotation direction of the brush, etc. can be appropriately selected.

[0158] [Water-based developer concentrate for flexographic printing plates]

[0159] The aqueous developer concentrate for flexographic printing plates of the present invention (hereinafter also referred to as "the concentrate of the present invention") is a concentrated aqueous developer for flexographic printing plates, and contains an anionic surfactant, a nonionic surfactant, and water.

[0160] [Anionic surfactant]

[0161] The anionic surfactant contained in the concentrated liquid of the present invention is not particularly limited, and conventionally known anionic surfactants can be used.

[0162] Examples of the anionic surfactant include fatty acid salts, rosin acid salts, hydroxyalkyl sulfonates, alkane sulfonates, dialkyl sulfosuccinates, linear alkylbenzene sulfonates, branched alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxypolyoxyethylene propyl sulfonates, polyoxyethylene alkylsulfophenyl ether salts, sodium N-methyl-N-oleyl taurate, disodium N-alkylsulfosuccinic acid monoamide, petroleum sulfonates, sulfated castor oil, and sulfated tallow oil. , sulfate salts of fatty acid alkyl esters, alkyl sulfate salts, polyoxyethylene alkyl ether sulfate salts, fatty acid monoglyceride sulfate salts, polyoxyethylene alkylphenyl ether sulfate salts, polyoxyethylene styrylphenyl ether sulfate salts, alkyl phosphate salts, polyoxyethylene alkyl ether phosphate salts, polyoxyethylene alkylphenyl ether alkenoate salts, partially saponified products of styrene-maleic anhydride copolymers, partially saponified products of olefin-maleic anhydride copolymers, naphthalenesulfonate formalin condensates, etc.

[0163] In the present invention, the anionic surfactant for the developer prepared by diluting the concentrated solution of the present invention is preferably a compound represented by the above formula (1) because it can suppress the formation of a film on the liquid surface.

[0164] In the present invention, for the developer prepared by diluting the concentrated solution of the present invention, it is preferred that R in the above formula (1) is 1 The number of carbon atoms is 6 to 14. Specifically, R in the above formula (1) 1 An alkyl group having 6 to 14 carbon atoms is more preferred, and an alkyl group having 6 to 10 carbon atoms is even more preferred because aggregation of development residue (dispersion) can be suppressed during development using a developer prepared by diluting the concentrated solution of the present invention.

[0165] In the present invention, for the developer prepared by diluting the concentrated solution of the present invention, the compound represented by the above formula (1) preferably has an HLB value of 8 or less and is water-soluble because formation of a film on the liquid surface can be suppressed.

[0166] Furthermore, it is preferred that the compound represented by the above formula (1) has an HLB value of 3 or more.

[0167] In the present invention, the content of the anionic surfactant is preferably 0.02 to 40% by mass, more preferably 3 to 25% by mass, based on the total mass of the concentrated liquid of the present invention.

[0168] [Nonionic surfactant]

[0169] The nonionic surfactant contained in the concentrated solution of the present invention is not particularly limited, and the nonionic surfactants described in the developer of the present invention can be used.

[0170] In the present invention, the nonionic surfactant is preferably a compound represented by the above formula (2) because it provides better storage stability and can suppress aggregation of development residue (dispersion) during development using a developer prepared by diluting the concentrated solution of the present invention.

[0171] In the present invention, the content of the nonionic surfactant is preferably 0.02 to 40% by mass, more preferably 3 to 25% by mass, based on the total mass of the concentrated liquid of the present invention.

[0172] 〔water〕

[0173] The water contained in the concentrated solution of the present invention is not particularly limited, and the water described in the developer of the present invention can be used.

[0174] The water content in the concentrated solution of the present invention can be adjusted by the degree of concentration and is not particularly limited, but is preferably less than 80% by mass, more preferably 50% by mass or more and less than 80% by mass, relative to the total mass of the concentrated solution of the present invention.

[0175] [Alkali]

[0176] The concentrated solution of the present invention preferably contains an alkali agent because the developing property of the developer prepared by diluting the concentrated solution of the present invention becomes good.

[0177] The alkali agent is not particularly limited, and the alkali agents described in the developer of the present invention can be used.

[0178] Furthermore, when the alkali agent is contained, the content thereof is preferably 0.1 to 10% by mass, more preferably 1 to 5% by mass, relative to the total mass of the concentrated liquid of the present invention.

[0179] 〔Chelating agent〕

[0180] In development performed using a developer prepared by diluting the concentrated solution of the present invention, the concentrated solution of the present invention preferably contains a chelating agent because aggregation of development residues can be suppressed.

[0181] The chelating agent is not particularly limited, and the chelating agents described in the developer of the present invention can be used.

[0182] [Other ingredients]

[0183] The concentrated solution of the present invention can be blended with various additives as optional components as needed.

[0184] As additives, for example, alkanolamines such as ethanolamine; preservatives such as benzotriazole and benzoic acid; freezing point depression agents such as glycols (for example, ethylene glycol, etc.) and lower alcohols (for example, ethanol, etc.); defoaming agents such as silicones and polyols; etc. can be appropriately added within the range that does not impair the effects of the present invention.

[0185] [Development Method]

[0186] Regarding the development method using the concentrated solution of the present invention, in addition to using an aqueous developer obtained by diluting the concentrated solution of the present invention, methods similar to the development methods using conventionally known aqueous developers can also be mentioned. For example, the following method can be mentioned, that is, the aqueous developer is brought into contact with the unexposed part of the flexographic printing plate precursor, and physical effects such as a brush, water pressure, and ultrasound are applied to disperse the photosensitive layer (photosensitive resin composition) constituting the unexposed part in the aqueous developer and remove it.

[0187] Here, the method for diluting the concentrated solution of the present invention is not particularly limited, and an example thereof includes a method of diluting the concentrated solution 2 to 20 times with water.

[0188] Furthermore, the aqueous developer may be used to immerse the unexposed portion, and may be continuously supplied so as to contact the unexposed portion while applying a physical action.

[0189] Furthermore, the liquid temperature of the aqueous developer during development is preferably 20 to 60°C, more preferably 30 to 50°C.

[0190] Furthermore, as a physical force commonly used, a brush is used, and the material, thickness, length, density and arrangement of the bristles, the movement and rotation direction of the brush, etc. can be appropriately selected.

[0191] 〔Flexographic printing plate〕

[0192] The photosensitive layer (photosensitive resin composition) of the flexographic printing plate precursor developed using the developer or concentrated solution of the present invention can use a conventionally known photosensitive resin composition, for example, a resin composition containing a water-dispersible latex, rubber, a photopolymerizable monomer, a photopolymerization initiator and a surfactant.

[0193] <Water-dispersible latex>

[0194] The water-dispersible latex contained in the resin composition is not particularly limited, and conventionally known water-dispersible latexes used for flexographic printing plates can be used.

[0195] Specific examples of the water-dispersible latex include water-dispersible latex polymers such as polybutadiene latex, natural rubber latex, styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, polychloroprene latex, polyisoprene latex, polyurethane latex, methyl methacrylate-butadiene copolymer latex, vinylpyridine polymer latex, butyl polymer latex, thiol polymer latex, and acrylate polymer latex; polymers obtained by copolymerizing other components such as acrylic acid and methacrylic acid with these polymers; and the like. These may be used alone or in combination of two or more.

[0196] <Rubber>

[0197] The rubber contained in the resin composition is not particularly limited, and conventionally known rubber materials used for flexographic printing plates can be used.

[0198] Specific examples of the rubber include butadiene rubber (BR), nitrile rubber (NBR), acrylic rubber, epichlorohydrin rubber, polyurethane rubber, isoprene rubber, styrene isoprene rubber, styrene butadiene rubber, ethylene-propylene copolymer, and chlorinated polyethylene. These may be used alone or in combination of two or more.

[0199] <Photopolymerizable Monomer>

[0200] The photopolymerizable monomer contained in the resin composition is not particularly limited, and conventionally known photopolymerizable monomers used for flexographic printing plates can be used.

[0201] Examples of the photopolymerizable monomer include ethylenically unsaturated compounds.

[0202] Specific examples of the ethylenically unsaturated compound include (meth)acrylic acid monomers, (meth)acrylic acid oligomers, and (meth)acrylic acid-modified polymers.

[0203] Specific examples of the (meth)acrylic acid-modified polymer include (meth)acrylic acid-modified butadiene rubber and (meth)acrylic acid-modified nitrile rubber.

[0204] In addition, "(meth)acrylic acid" is an expression which means acrylic acid or methacrylic acid.

[0205] <Photopolymerization Initiator>

[0206] The photopolymerization initiator contained in the resin composition is not particularly limited as long as it initiates the photopolymerization of the above-mentioned photopolymerizable monomers. Examples thereof include alkyl phenones, acetophenones, benzoin ethers, benzophenones, thioxanthones, anthraquinones, benzyls, and diacetyl photopolymerization initiators.

[0207] Specific examples include benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, methyl o-benzoylbenzoate, and 1-hydroxycyclohexyl phenyl ketone.

[0208] <Surfactant>

[0209] From the viewpoint of improving water developability, the resin composition preferably contains a surfactant.

[0210] Examples of the surfactant include cationic surfactants, anionic surfactants, and nonionic surfactants, among which anionic surfactants are preferred.

[0211] Specific examples of the anionic surfactant include

[0212] Aliphatic carboxylates such as sodium laurate and sodium oleate;

[0213] Sodium lauryl sulfate, sodium hexadecyl sulfate, sodium oleyl sulfate and other higher alcohol sulfates;

[0214] Polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate;

[0215] Polyoxyethylene alkyl allyl ether sulfates such as polyoxyethylene octylphenyl ether sodium sulfate and polyoxyethylene nonylphenyl ether sodium sulfate;

[0216] Alkyl sulfonates such as alkyl diphenyl ether disulfonate, sodium dodecyl sulfonate, and sodium dialkyl sulfosuccinate;

[0217] Alkyl allyl sulfonates such as alkyl disulfonates, sodium dodecylbenzenesulfonate, sodium dibutylnaphthalenesulfonate, and sodium triisopropylnaphthalenesulfonate;

[0218] Higher alcohol phosphate salts such as disodium lauryl phosphate monoester and sodium lauryl phosphate diester;

[0219] Disodium lauryl polyoxyethylene ether phosphate monoester, sodium lauryl polyoxyethylene ether phosphate diester and other polyoxyethylene alkyl ether phosphate salts; etc.

[0220] These may be used alone or in combination of two or more.

[0221] [Method for manufacturing flexographic printing plates]

[0222] The method for manufacturing a flexographic printing plate of the present invention comprises: an exposure step of exposing a photosensitive layer in the form of an image on a flexographic printing plate precursor having a photosensitive layer; a development step of developing the flexographic printing plate of the present invention using an aqueous developer or a liquid obtained by diluting the aqueous developer concentrate of the flexographic printing plate of the present invention by 2 to 20 times, thereby forming a non-image area and an image area; and a rinsing step of rinsing with water after the development step.

[0223] [Exposure process]

[0224] The exposure step is a step of irradiating the photosensitive layer with active light in an image-wise manner to cause crosslinking and / or polymerization in the region irradiated with the active light, thereby curing the layer.

[0225] The exposure step can be performed by exposing the photosensitive layer through a mask provided on the outer surface thereof.

[0226] Furthermore, it is also preferable to use a vacuum frame exposure apparatus. In this case, exposure with active light is performed after the air between the relief-forming layer and the mask is exhausted.

[0227] Furthermore, the exposure may be performed in a state with a reduced oxygen concentration or in the air without particular limitation. However, from the viewpoint of preventing polymerization inhibition by oxygen, the exposure is preferably performed in a low oxygen concentration.

[0228] [Development process]

[0229] The above-mentioned development process is a process of forming a non-image part and an image part by developing the flexographic printing plate of the present invention using the aqueous developer or a liquid obtained by diluting the aqueous developer concentrate of the flexographic printing plate of the present invention by 2 to 20 times. Specifically, it is as described in the development method of the developer or concentrated solution of the present invention.

[0230] 〔Rinsing process〕

[0231] The rinsing step is a step of rinsing the surfaces of the non-image area and the image area formed in the development step with water.

[0232] Examples of the rinsing method in the above-mentioned rinsing step include a method of washing with tap water, a method of spraying high-pressure water with a sprayer, a method of using a well-known intermittent or conveying brush-type washing machine as a developer for flexographic printing plates to mainly brush the surfaces of the non-image area and the image area in the presence of water, etc.

[0233] Example

[0234] The present invention is further described in detail below with reference to the following examples. The materials, amounts, ratios, treatment contents, and treatment sequences shown in the following examples may be appropriately modified without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples.

[0235] [Examples 1 to 11 and Comparative Examples 1 to 5]

[0236] An aqueous developer was prepared by blending water, an alkali agent, a chelating agent, an anionic surfactant, and a nonionic surfactant shown in Table 1 below in parts by mass.

[0237] 〔Concentration suitability〕

[0238] The aqueous developer concentrate, prepared by concentrating the alkali agent and other components of the aqueous developer to a concentration 10 times, was visually observed for dissolution at room temperature (23°C) and evaluated according to the following criteria. The results are shown in Table 1. A rating of B or higher indicates no practical problems.

[0239] (Evaluation Criteria)

[0240] A: Colorless and transparent

[0241] B: White turbidity

[0242] C: Two-layer separation

[0243] D: Insoluble precipitate

[0244] Storage stability

[0245] <50℃ / 45 days>

[0246] The aqueous developer concentrate used in the evaluation of concentration suitability was stored in a 50°C oven for 45 days. The liquid state was then visually observed and evaluated according to the following criteria. The results are shown in Table 1. A rating of B or higher indicates no practical problems. Comparative Examples 1 to 4, due to the generation of insoluble matter before storage, were not evaluated and are marked as "-" in Table 1.

[0247] (Evaluation Criteria)

[0248] A: Colorless and transparent

[0249] B: White turbidity

[0250] C: Two-layer separation

[0251] <-5℃ / 60 days>

[0252] The aqueous developer concentrate used for the evaluation of concentration suitability was stored in a -5°C freezer for 60 days, and the liquid state was visually observed.

[0253] Also, when the evaluation liquid was frozen, the time until it melted again was measured.

[0254] Evaluation was performed based on the following criteria. The results are shown in Table 1 below. In addition, as long as the evaluation is B or above, there is no practical problem. Furthermore, since Comparative Examples 1 to 4 separated into two layers before storage, they were not evaluated and are marked as "-" in Table 1 below.

[0255] (Evaluation Criteria)

[0256] A: No freezing

[0257] B: The time from leaving the freezer to remelting is less than 6 hours

[0258] C: The time from leaving the freezer to remelting is more than 6 hours

[0259] 〔Developability〕

[0260] The cover film of the flexographic printing plate precursor [FLENEX FW-L2, manufactured by Fujifilm Corporation] was peeled off and exposed for 2 seconds (back exposure) from a position 15 cm from the substrate side using an exposure apparatus equipped with 15 arrayed 40 W chemical lamps.

[0261] Thereafter, development was performed for 3 minutes using a brush washer (liquid temperature 50° C.) filled with each of the prepared aqueous developers.

[0262] Afterwards, it was dried by hot air at 60°C until the moisture was removed. The thickness of the obtained flexographic printing plate was measured using a constant pressure thickness meter, and the film thickness change per minute (development speed) was calculated from the thickness change before and after development. Then, it was evaluated according to the following benchmarks. The results are shown in Table 1 below. In addition, as long as the evaluation is B or above, there is no problem in practical use.

[0263] (Evaluation Criteria)

[0264] A: Development speed is 170 μm / min or more

[0265] B: Development speed is 100 μm / min or more and less than 170 μm / min

[0266] C: Development speed less than 100μm / min

[0267] 〔Agglomerated residue〕

[0268] The cover film of the flexographic printing plate precursor [FLENEX FW-L2, manufactured by Fujifilm Corporation] was peeled off and exposed for 2 seconds (back exposure) from a position 15 cm from the substrate side using an exposure apparatus equipped with 15 arrayed 40 W chemical lamps.

[0269] Subsequently, development was performed using a brush washer (liquid temperature 50°C) filled with each of the prepared aqueous developers for an arbitrary time period until the solid content of the development residue (dispersion) reached 7.0% by mass. Regarding the solid content of the development residue, 2.0 g of the aqueous developer used (hereinafter also referred to as "exhausted solution") was weighed and dried at 95°C for 18 hours. The solid content percentage in the exhausted solution was calculated based on the weight change before and after drying.

[0270] Next, 7 g of the fatigue liquid was weighed into a container and diluted with 63 g of hard water (hardness 120). The agglomerated residue produced immediately after stirring was observed and evaluated according to the following criteria. The results are shown in Table 1. A rating of B or higher indicates no practical problems.

[0271] (Evaluation Criteria)

[0272] A: No condensation will be generated, and no attachment will be generated at the gas-liquid interface of the container

[0273] B: Although no condensation occurs, adhesion occurs at the gas-liquid interface of the container.

[0274] C: Producing condensates

[0275] [Coating inhibition]

[0276] The cover film of the flexographic printing plate precursor [FLENEX FW-L2, manufactured by Fujifilm Corporation] was peeled off and exposed for 2 seconds (back exposure) from a position 15 cm from the substrate side using an exposure apparatus equipped with 15 arrayed 40 W chemical lamps.

[0277] Subsequently, development was performed using a brush washer (liquid temperature 50°C) filled with each of the prepared aqueous developers for an arbitrary time period until the solid content of the development residue (dispersion) reached 7.0% by mass. Regarding the solid content of the development residue, 2.0 g of the aqueous developer used (hereinafter also referred to as "exhausted solution") was weighed and dried at 95°C for 18 hours. The solid content percentage in the exhausted solution was calculated based on the weight change before and after drying.

[0278] Next, 50 g of the fatigue liquid was weighed into a container and heated in a 50°C oven with the lid open for 5 hours. The container was then left at room temperature (23°C) for 12 hours. The film strength on the liquid surface was then visually observed and evaluated according to the following criteria. The results are shown in Table 1. A rating of B or higher indicates no practical problems.

[0279] (Evaluation Criteria)

[0280] A: No film is formed

[0281] B: Although a film is formed, it can be redispersed after stirring

[0282] C: Forms a film that will not disperse even if stirred

[0283]

[0284] The following components were used as the components in Table 1 above.

[0285] Sodium carbonate: Reagent manufactured by FUJIFILM Wako Pure Chemical Corporation

[0286] ·EDDS: Octaquest E30 (manufactured by Inno Spec specialty chemicals Corporation)

[0287] Sodium valerate: Reagent manufactured by FUJIFILM Wako Pure Chemical Corporation

[0288] Sodium octanoate: Reagent manufactured by FUJ IFILM Wako Pure Chemical Corporation

[0289] Sodium laurate: Reagent manufactured by FUJIFILM Wako Pure Chemical Corporation

[0290] Sodium lauryl sulfate: Reagent manufactured by FUJIFILM Wako Pure Chemical Corporation

[0291] Sodium lauryl sulfonate: Reagent manufactured by FUJIFILM Wako Pure Chemical Corporation

[0292] Sodium lauryl phosphate: a reagent manufactured by Tokyo Chemical Industry Co., Ltd.

[0293] PIONIN D-6120: Polyoxyethylene polystyrylphenyl ether (manufactured by TAKEMOTO OIL & FAT CO., LTD.)

[0294] PIONIN D-1105: Polyoxyethylene lauryl ether (manufactured by TAKEMOTO OIL & FAT CO., LTD.)

[0295] Nonylphenol polyoxyethylene ether: EMULGEN905 (manufactured by Kao Corporation)

[0296] As shown in Table 1, it was found that when only anionic surfactants were added without the nonionic surfactants, the concentration suitability was poor (Comparative Examples 1 to 4).

[0297] Furthermore, it was found that when only a nonionic surfactant was added without adding an anionic surfactant, the storage stability was poor (Comparative Example 5).

[0298] On the other hand, it was found that by blending both an anionic surfactant and a nonionic surfactant, the concentration suitability was excellent and the storage stability was also good (Examples 1 to 11).

[0299] In particular, from the comparison between Example 2 and Example 7 and the comparison between Example 3 and Example 8, it can be seen that when an alkali agent is added, the developability of the aqueous developer prepared using the diluted concentrated solution is further improved.

[0300] Furthermore, from the comparison of Examples 1 to 6, it is found that when the anionic surfactant is a compound represented by the above formula (1), the formation of a film on the liquid surface of the aqueous developer prepared by diluting the concentrated solution can be suppressed.

[0301] Furthermore, a comparison between Examples 8 and 9 shows that when the nonionic surfactant is a compound represented by the above formula (2), aggregation of development residue (dispersion) can be suppressed during development using an aqueous developer prepared by diluting the concentrated solution.

Claims

1. A water-based developer for flexographic printing plates, comprising an anionic surfactant, a nonionic surfactant and water, The anionic surfactant is a compound represented by the following formula (1): R 1 -X 1 (1) Here, in the formula (1), R 1 represents an alkyl group having 3 to 20 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, or an alkynyl group having 3 to 20 carbon atoms, which may have a substituent, X 1 represents a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a sulfuric acid group or a salt thereof, or a phosphoric acid group or a salt thereof, The nonionic surfactant is a compound represented by the following formula (2): Here, in the formula (2), Ar represents an m-valent aromatic group, where m represents an integer of 1 to 8, X 2 represents an aralkyl group, and p represents an integer from 1 to 3, wherein p<m, when p is 2 or 3, multiple X 2 Same or different from each other, A represents an alkylene group having 2 to 4 carbon atoms, R 2 represents a hydrogen atom or an alkyl group, n represents an integer of 1 to 100, when n is an integer of 2 to 100, multiple A's are the same or different, when mp is an integer of 2 to 8, multiple A's, n's and R's are the same or different. 2 are the same as or different from each other.

2. The aqueous developer for flexographic printing plates according to claim 1, wherein The content of the anionic surfactant is 0.01% by mass to 10% by mass, and the content of the nonionic surfactant is 0.01% by mass to 10% by mass. 3 . The aqueous developer for flexographic printing plates according to claim 1 , further comprising an alkali agent.

4. The aqueous developer for flexographic printing plates according to claim 1 or 2, wherein R in the formula (1) 1 The number of carbon atoms is 6 to 14.

5. The aqueous developer for flexographic printing plates according to claim 1 or 2, wherein The compound represented by the formula (1) has an HLB value of 8 or less and is water-soluble.

6. A method for manufacturing a flexographic printing plate, the flexographic printing plate having a non-image area and an image area, the method comprising: An exposure step of exposing the photosensitive layer of the flexographic printing plate precursor having the photosensitive layer in the form of an image; a developing step of developing the flexographic printing plate using the aqueous developer according to any one of claims 1 to 5 after the exposure step to form a non-image area and an image area; and The rinsing step is performed using water after the development step.

7. A concentrated aqueous developer for flexographic printing plates, comprising an anionic surfactant, a nonionic surfactant, and water. The anionic surfactant is a compound represented by the following formula (1): R 1 -X 1 (1) Here, in the formula (1), R 1 represents an alkyl group having 3 to 20 carbon atoms, an alkenyl group having 3 to 20 carbon atoms, or an alkynyl group having 3 to 20 carbon atoms, which may have a substituent, X 1 represents a carboxylic acid group or a salt thereof, a sulfonic acid group or a salt thereof, a sulfuric acid group or a salt thereof, or a phosphoric acid group or a salt thereof, The nonionic surfactant is a compound represented by the following formula (2): Here, in the formula (2), Ar represents an m-valent aromatic group, where m represents an integer of 1 to 8, X 2 represents an aralkyl group, and p represents an integer from 1 to 3, wherein p<m, when p is 2 or 3, multiple X 2 Same or different from each other, A represents an alkylene group having 2 to 4 carbon atoms, R 2 represents a hydrogen atom or an alkyl group, n represents an integer of 1 to 100, when n is an integer of 2 to 100, multiple A's are the same or different, when mp is an integer of 2 to 8, multiple A's, n's and R's are the same or different. 2 are the same as or different from each other.

8. The aqueous developer concentrate for flexographic printing plates according to claim 7, wherein The content of the anionic surfactant is 0.02% by mass to 40% by mass, and the content of the nonionic surfactant is 0.02% by mass to 40% by mass. 9 . The aqueous developer concentrate for flexographic printing plates according to claim 7 , further comprising an alkali agent.

10. The aqueous developer concentrate for flexographic printing plates according to claim 7 or 8, wherein R in the formula (1) 1 The number of carbon atoms is 6 to 14.

11. The aqueous developer concentrate for flexographic printing plates according to claim 7 or 8, wherein The compound represented by the formula (1) has an HLB value of 8 or less and is water-soluble.

12. A method for manufacturing a flexographic printing plate, the flexographic printing plate having a non-image area and an image area, the method comprising: An exposure step of exposing the photosensitive layer of the flexographic printing plate precursor having the photosensitive layer in the form of an image; a developing step, after the exposure step, developing the flexographic printing plate using a liquid prepared by diluting the aqueous developer concentrate according to any one of claims 7 to 11 by 2 to 20 times to form a non-image area and an image area; and The rinsing step is performed using water after the development step.

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