Film for manufacturing flexographic printing plate, laminate, and method for manufacturing flexographic printing plate

Abstract

A film for manufacturing a flexographic printing plate, which comprises a base material and an ablation layer laminated on the base material, the ablation layer containing a resin having a structural unit (1) represented by general formula (1), and the thickness of the base material being 10 [mu] m or more and less than 100 [mu] m. (In formula (1), R1 and R2 each independently represent a non-polar group, and R3 and R4 each independently represent a hydrogen atom or a non-polar group. > # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a film for manufacturing a flexible printing plate, a laminate and a method for manufacturing a flexible printing plate. Background Art

[0002] In recent years, flexographic printing using a flexographic printing plate has been widely used as a method for printing on flexible packaging materials such as paper and film.

[0003] As a method for producing a flexographic printing plate, there is, for example, the following method.

[0004] First, a flexographic printing plate having a photosensitive resin composition layer on a support is subjected to ultraviolet exposure (back exposure) from the support side to form a uniform photocured layer.

[0005] Next, relief exposure is performed from the back side, that is, the side opposite to the above-mentioned ultraviolet-exposed side, on the uncured photosensitive resin composition layer. As the above-mentioned relief exposure method, there are a method of ultraviolet exposure through a transparent image carrier (mask) such as a negative film that selectively transmits ultraviolet rays; a method of forming a thin layer of ultraviolet transmission part by infrared laser ablation of an image that becomes digital information, and ultraviolet exposure through the thin layer, etc.

[0006] Then, the photosensitive resin composition in the unexposed portion of the flexographic printing original plate is washed away, and then developed to form a relief image, thereby obtaining a flexographic printing plate.

[0007] In the development of photosensitive resin compositions, due to the increase in environmental awareness in recent years, water development methods that do not use organic solvents and thermal development methods that do not use developer solutions are being studied. However, these methods all have the following problems: they are based on the premise that the photosensitive resin composition in the unexposed portion is removed and discarded in the development process, and there is still room for improvement from the perspective of reducing the load on the environment.

[0008] As an improvement method from the perspective of reducing the load on the environment, a method for manufacturing a flexographic printing plate using a liquid photosensitive resin composition is proposed, which recycles the photosensitive resin composition of the unexposed portion and reuses it in the manufacture of the flexographic printing plate (for example, refer to patent document 1). The method for manufacturing a flexographic printing plate described in patent document 1 can take into account both reducing the amount of waste of the photosensitive resin composition of the unexposed portion and reducing the production cost of the flexographic printing plate, and is therefore widely used as a method for manufacturing a flexographic printing plate with high environmental adaptability. On the other hand, in the method for manufacturing the flexographic printing plate, it is important to recycle the photosensitive resin composition of the unexposed portion in a state that is not inferior to that when it is not used.

[0009] In recent years, CTP (Computer To Plate) technology has become known as a method for producing a flexographic printing plate.

[0010] The CTP technology is as follows: an ablation layer that can be ablated by infrared rays is provided on the photosensitive resin composition layer, and the ablation layer is removed into a desired shape by irradiating an infrared laser, thereby forming a negative-type active light-transmitting portion. Next, the photosensitive resin composition layer is irradiated with ultraviolet rays using the ablation layer as a mask, and the photosensitive resin composition is reacted in the same shape as the transmissive portion formed in the ablation layer, and relief exposure is performed. Finally, the unnecessary ablation layer and the unexposed portion of the photosensitive resin composition are developed and removed to manufacture a flexographic printing plate.

[0011] However, in the above-mentioned method for manufacturing a flexographic printing plate, the ablation layer is designed to have high adhesion to the photosensitive resin composition from the viewpoint of ensuring practicality, so it is difficult to separate and recover the photosensitive resin composition of the unexposed portion after relief exposure. In addition, there is the problem that the ablation layer cannot be completely prevented from eluting and transferring into the photosensitive resin composition, which not only makes it difficult to separate and recover the unexposed portion, but also leaves room for improvement from the viewpoint of ensuring the quality of the flexographic printing plate.

[0012] Here, “elution” means that the components constituting the ablation layer are independently mixed into the photosensitive resin composition, and “transfer” means that the ablation layer is peeled off from the substrate while maintaining the film shape and mixed into the photosensitive resin composition.

[0013] As a countermeasure to the above problems, a method has been proposed in which an image mask is formed by irradiating a flexographic printing plate having a photosensitive resin composition layer, a thin film layer, and an optical density variable layer corresponding to an ablation layer on a predetermined support with infrared laser light (for example, see Patent Document 2).

[0014] In this method, ultraviolet rays are irradiated on the above-mentioned image mask for full-surface exposure, and then the image mask is peeled off together with the film layer, and then development is performed to obtain a flexographic printing plate. In this method, since the optical density variable layer corresponding to the ablation layer is removed before development, there is an advantage that elution and transfer to the photosensitive resin composition layer can be suppressed.

[0015] However, if the film thickness of the thin film layer between the photosensitive resin composition layer and the optical density variable layer is too thick, ultraviolet rays are easily refracted and scattered, which causes a problem of reduced image reproducibility.

[0016] As a technology for preventing the above-mentioned reduction in image reproducibility and preventing the dissolution and transfer of the ablation layer to the photosensitive resin composition layer, a method for manufacturing a flexographic printing plate has been proposed, which uses a layer formed by cross-linking a curable resin as a water-insoluble heat-sensitive mask layer stacked on the photosensitive resin composition layer to perform pattern exposure (for example, refer to Patent Document 3).

[0017] Prior art literature

[0018] Patent Literature

[0019] Patent Document 1: Japanese Patent No. 5996197

[0020] Patent Document 2: International Publication No. 01 / 18605

[0021] Patent Document 3: Japanese Patent No. 4442187 Summary of the invention

[0022] Problem that the invention aims to solve

[0023] However, in the method for manufacturing a flexographic printing plate proposed in Patent Document 3, when a predetermined adhesion adjustment layer is not provided between the photosensitive resin composition layer and the heat-sensitive mask layer, there is a problem that the adhesion between the photosensitive resin composition layer and the heat-sensitive mask layer becomes too much, and dissolution and transfer between the layers cannot be avoided. In addition, since a heat treatment is required when laminating the heat-sensitive mask layer on the photosensitive resin composition layer, there is a problem that there is a concern that the finally obtained flexographic printing plate may be damaged or the unexposed portion may be thermally degraded.

[0024] Therefore, in view of the above-mentioned problems of the prior art, the present invention aims to provide a film for manufacturing a flexographic printing plate which can suppress the dissolution and transfer of the ablation layer to the photosensitive resin composition layer and can be used to manufacture a flexographic printing plate with excellent image reproducibility, and a method for manufacturing a flexographic printing plate using the film.

[0025] Solutions for solving problems

[0026] The present inventors have conducted intensive studies to solve the above problems and have found that the above problems can be solved by a thin film having an infrared ablation layer and a substrate with specific structures, thereby completing the present invention.

[0027] That is, the present invention is as follows. [1]

[0029] A film for producing a flexible printing plate, comprising a substrate and an ablation layer laminated on the substrate, the ablation layer containing a resin having a structural unit (1) represented by the following general formula (1), wherein the thickness of the substrate is 10 μm or more and less than 100 μm.

[0030]

[0031] In formula (1), R1 and R2 each independently represent a non-polar group, and R3 and R4 each independently represent a hydrogen atom or a non-polar group. [2]

[0033] The film for producing a flexographic printing plate according to the above [1], wherein in the formula (1), R1 and R2 are each independently any one selected from the group consisting of an alkyl group, an alkenyl group and an alkynyl group,

[0034] R3 and R4 are each independently any one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an alkynyl group. [3]

[0036] The film for producing a flexographic printing plate according to [1] or [2], wherein in the formula (1), R1 and R2 are each independently an alkyl group,

[0037] R3 and R4 are each independently a hydrogen atom or an alkyl group. [4]

[0039] The film for producing a flexographic printing plate according to any one of [1] to [3], wherein the resin further comprises a structural unit (2) derived from a monovinyl-substituted aromatic hydrocarbon. [5]

[0041] The film for producing a flexographic printing plate according to any one of [1] to [4] above, wherein the substrate comprises a resin having a polyester skeleton or a polyolefin skeleton. [6]

[0043] The film for producing a flexographic printing plate according to any one of [1] to [5], wherein the substrate is formed of a resin having a polyester skeleton or a polyolefin skeleton. [7]

[0045] The film for producing a flexographic printing plate according to any one of [1] to [6] above, wherein the substrate is formed of a resin having a polyolefin skeleton. [8]

[0047] A laminated body comprising:

[0048] Flexographic printing plate having a photosensitive resin composition layer, and

[0049] The film for producing a flexographic printing plate according to any one of [1] to [7] above on the flexographic printing original plate. [9]

[0051] A method for producing a flexographic printing plate, comprising producing a flexographic printing plate using the laminate described in [8] above,

[0052] The method for manufacturing the flexographic printing plate comprises:

[0053] a drawing step of irradiating the film for producing a flexographic printing plate according to any one of [1] to [7] above with infrared rays to draw a processing pattern;

[0054] an exposure step of irradiating the photosensitive resin composition layer with ultraviolet rays using the ablation layer having a pattern drawn in the drawing step as a mask to form a pattern;

[0055] The developing step is to remove the unexposed portion of the photosensitive resin composition layer.

[10]

[0057] The method for producing a flexographic printing plate according to the above [9], wherein the photosensitive resin composition contains a polymer having a carbonyl group.

[11]

[0059] The method for producing a flexographic printing plate according to [9] or

[10] , wherein the substrate of the film for producing a flexographic printing plate is formed of a resin having a polyester skeleton or a polyolefin skeleton.

[12]

[0061] The method for producing a flexographic printing plate according to any one of [9] to

[11] above, wherein the substrate of the film for producing a flexographic printing plate is formed of a resin having a polyolefin skeleton.

[13]

[0063] The method for producing a flexographic printing plate according to any one of [9] to

[12] , further comprising:

[0064] The recovery step is to recover the unexposed portion removed in the development step and use it in the production of a new flexographic printing plate.

[0065] Effects of the Invention

[0066] The present invention can provide a film for producing a flexographic printing plate, a laminate, and a method for producing a flexographic printing plate using the same, which can suppress the elution and transfer of the ablation layer to the photosensitive resin composition layer and can produce a flexographic printing plate having excellent image reproducibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] [ Figure 1 ] is a schematic cross-sectional view of a film for manufacturing a flexible printing plate according to the present invention.

[0068] [ Figure 2] is a schematic diagram showing a method for producing a flexographic printing plate using the film for producing a flexographic printing plate of the present invention. DETAILED DESCRIPTION

[0069] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail.

[0070] It should be noted that the following embodiments are examples for explaining the present invention and are not intended to limit the present invention to the following contents.

[0071] The present invention can be implemented with appropriate modifications without departing from the gist of the invention.

[0072] [Film for flexographic printing plate manufacturing]

[0073] The film for producing a flexographic printing plate of this embodiment comprises: a substrate and an ablation layer laminated on the substrate, the ablation layer containing a resin having a structural unit (1) represented by the following general formula (1), wherein the thickness of the substrate is 10 μm or more and less than 100 μm.

[0074]

[0075] In formula (1), R1 and R2 each independently represent a nonpolar group, and R3 and R4 each independently represent a hydrogen atom or a nonpolar group.

[0076] Figure 1 A schematic cross-sectional view of the film for producing a flexographic printing plate according to the present embodiment is shown.

[0077] The film for manufacturing a flexographic printing plate of the present embodiment is formed by laminating a substrate 1 and an ablation layer 2 that functions as a mask when forming a desired concavo-convex pattern of a flexographic printing plate.

[0078] Hereinafter, the film for producing a flexographic printing plate according to the present embodiment will be described in detail.

[0079] (Base material)

[0080] The film for manufacturing a flexographic printing plate of this embodiment comprises a substrate 1 and an ablation layer 2 laminated on the substrate 1. The ablation layer 2 is subjected to image drawing to function as a negative film for forming a relief in the manufacturing process of a flexographic printing plate described later.

[0081] The quality of relief, especially the image reproducibility, is greatly affected by the negative film through which the ultraviolet light passes during relief exposure. Generally, the thicker the negative film, the greater the refraction and scattering of the ultraviolet light in the negative film, and the image reproducibility tends to decrease. Figure 1The thickness of the substrate 1 shown accounts for the majority, and therefore the smaller the thickness of the substrate 1 is, the more preferable it is from the viewpoint of the quality of the flexographic printing plate.

[0082] On the other hand, it is also important that the negative film has a certain rigidity and dimensional stability. If the negative film is easily deformed, deformation and damage of the image formed on the negative film are induced in the process before relief exposure, resulting in a tendency for image reproducibility to decrease. However, when the rigidity of the negative film is too high, there is a tendency to produce poor compatibility with the device in the manufacturing process of the target flexographic printing plate, or excessive stress concentration on the ablation layer during processing, causing irreversible damage such as scratches and wrinkles.

[0083] From the above viewpoints, the thickness of the substrate 1 is 10 μm or more and less than 100 μm. By using the above numerical range, a film for manufacturing a flexographic printing plate having excellent image reproducibility and moderate rigidity can be obtained. Furthermore, it is preferably 20 μm or more, and more preferably 40 μm or more. By making the thickness of the substrate 1 more than 10 μm, sufficient strength and rigidity can be obtained in practical use, and deformation and damage of the image can be suppressed in the manufacturing process of the flexographic printing plate. In addition, from the viewpoint of ensuring moderate flexibility and making the operability in the manufacturing process of the flexographic printing plate good, the thickness of the substrate 1 is set to be less than 100 μm, preferably less than 90 μm, and more preferably less than 70 μm.

[0084] In addition, the substrate 1 preferably contains a resin having a polyester skeleton or a polyolefin skeleton from the viewpoint of dimensional stability, transparency, and adhesion to the ablation layer 2. Here, the resin contained in the substrate 1 may be a mixture of a resin having a polyester skeleton and a resin having a polyolefin skeleton, or may be a copolymer.

[0085] Examples of the polyester include, but are not limited to, polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0086] Examples of the resin having a polyolefin skeleton include, but are not limited to, polyethylene, polypropylene, and resins obtained by copolymerizing these.

[0087] In addition, from the viewpoint of image reproducibility, the substrate 1 is more preferably formed of a resin having a polyester skeleton or a polyolefin skeleton, and is further preferably formed of a resin having a polyolefin skeleton. This is because a resin having a polyolefin skeleton has a high oxygen permeability. Here, the oxygen permeability is one of the physical properties of the film, which indicates the oxygen permeability per 1m under the condition of 1atm (1 atmosphere). 2 The amount of oxygen that passes through the film in one day. The unit is cm 3 / m 2 ·24h·atm. The larger the value, the easier it is to pass; the smaller the value, the harder it is to pass.

[0088] In the manufacturing process of the flexographic printing plate, when the photosensitive resin composition layer is cured by ultraviolet irradiation, the curing is carried out by free radical polymerization. During the free radical polymerization, when oxygen coexists, the free radical generating compound reacts with oxygen to hinder the polymerization reaction. That is, by reducing the amount of oxygen coexisting during the exposure of the photosensitive resin composition layer, the degree of polymerization can be increased, and the image reproducibility of the final flexographic printing plate can be improved. Here, if the substrate 1 of the film for manufacturing the flexographic printing plate of the present embodiment laminated on the photosensitive resin composition has a high oxygen permeability, the oxygen remaining on the surface and / or inside of the photosensitive resin composition layer during ultraviolet irradiation is easy to diffuse to the outside, and the influence of the polymerization reaction hindered by oxygen can be suppressed.

[0089] In the film for manufacturing a flexographic printing plate of the present embodiment, the substrate can be used in an untreated state, or a predetermined surface treatment can be performed as required, or a substrate to which a function of antistatic treatment etc. can be given can be used. As the surface treatment, for example, corona treatment, roughening etc. can be listed.

[0090] (ablation layer)

[0091] like Figure 1 As shown, the film for producing a flexographic printing plate according to the present embodiment includes a substrate 1 and an ablation layer 2 laminated thereon.

[0092] The ablation layer 2 contains a predetermined resin, can be removed by infrared laser, and has a function as a light shielding layer other than infrared rays.

[0093] In order to suppress the dissolution of components contained in the ablation layer 2 into the photosensitive resin composition layer and the transfer of the ablation layer 2 into the photosensitive resin composition, it is preferred to improve the adhesion between the substrate 1 and the ablation layer 2 or reduce the compatibility between the ablation layer 2 and the photosensitive resin composition layer.

[0094] The components contained in the ablation layer 2 are resin, infrared absorbing material, shielding material, and the like.

[0095] From the viewpoint of improving the adhesion between the substrate 1 and the ablation layer 2, it is important to strengthen the interaction between the layers. As a method for strengthening the interaction between the layers, for example, a method of imparting similar molecular structures to the constituent materials of both the substrate 1 and the ablation layer 2 in order to enhance the chemical interaction, and a method of enhancing the physical interaction can be cited. As a method for enhancing the physical interaction, for example, a method of enhancing the flexibility of the ablation layer 2 or imparting appropriate softness in order to suppress peeling when the film is bent can be cited. On the other hand, a method of ensuring high ablation efficiency of the infrared laser while maintaining the adhesion between the layers is also effective.

[0096] From the above viewpoints, in the film for producing a flexographic printing plate of the present embodiment, the ablation layer 2 comprises a resin having a structural unit (1) represented by the following general formula (1) and comprising a quaternary carbon atom to which two nonpolar groups are bonded.

[0097] It should be noted that the resin may have other structural units as required.

[0098] In the present specification, a "monomer" refers to a compound before polymerization, and a "structural unit" refers to a predetermined repeating unit constituted by polymerization of a monomer.

[0099]

[0100] In formula (1), R1 and R2 each independently represent a nonpolar group, and R3 and R4 each independently represent a hydrogen atom or a nonpolar group.

[0101] <Resin having structural unit (1) represented by general formula (1)>

[0102] As described above, the ablation layer 2 of the film for producing a flexographic printing plate according to the present embodiment contains a resin having the structural unit (1) represented by the general formula (1).

[0103] When the resin contained in the ablation layer 2 has a polar group on the main chain, non-covalent bonds between molecules are firmly formed, and the strength of the ablation layer 2 is improved. On the other hand, the structure used for interaction with the constituent materials of the substrate 1 is reduced, and there is a tendency for the adhesion between the substrate 1 and the ablation layer 2 to decrease. In addition, the rigidity of the ablation layer 2 becomes too high, and the stress caused by bending or stretching is concentrated between the layers, which tends to easily cause interface peeling.

[0104] Furthermore, when the resin contained in the ablation layer 2 has a polar group in a side chain, this tends to be undesirable from the viewpoint of the efficiency of ablation of the ablation layer 2 by laser light, as described below.

[0105] In order to ensure the efficiency of ablation by laser, it is important that the above-mentioned resin contained in the ablation layer 2 is easily depolymerized. "Depolymerization" refers to a reaction in which a polymer is decomposed into monomers by a reverse reaction of a polymerization reaction.

[0106] By irradiating the infrared laser, the ablation layer 2 instantly reaches a high temperature of several hundred degrees. At this time, the main chain of the above-mentioned resin is decomposed, the molecular weight drops sharply, and is removed from the ablation layer 2. However, in the case of resins that are difficult to depolymerize, only the side chains are decomposed during ablation, and the main chain is not cut. Therefore, the resin remains in the ablation layer 2 even after irradiating the infrared laser. It is known that the resin obtained by polycondensation forms a ring structure during decomposition, and the main chain is cut. That is, in a short-term heat treatment, i.e., infrared ablation, the molecular weight is difficult to reduce, and the ablation layer containing the resin obtained by the polycondensation tends to have poor removal efficiency.

[0107] From the above viewpoint, it is important that the ablation layer 2 contains a resin that is easily depolymerized. Generally, it is known that the cleavage of the main chain is easy to start from the thermally unstable part existing in the polymer such as the branch. However, if the side chain equivalent to the branch has polarity, the decomposition of the side chain is easy to occur dominantly, and it is difficult to cut the main chain, so it is not preferred.

[0108] Therefore, it is important that the side chain of the resin contained in the ablation layer 2 of the film for manufacturing a flexible printing plate of the present embodiment is a non-polar group. In addition, when the main chain is cleaved, the contribution of the chain transfer within or between molecules cannot be ignored. Therefore, it is preferred that there is no tertiary hydrogen that is easily taken away by chain transfer. That is, it is important that the part corresponding to the symmetry plane of the branch is also a non-polar group.

[0109] In addition, it is also important that the side chain is a non-polar group from the viewpoint of obtaining rubber-like elasticity. This serves as a soft portion in the elastomer, and the flexibility of the ablation layer 2 is improved.

[0110] From the above viewpoints, in the film for manufacturing a flexographic printing plate of this embodiment, the content of the resin having the structural unit (1) represented by the above general formula (1) in the ablation layer is preferably 20% by mass or more, more preferably 30% by mass or more, and further preferably 40% by mass or more.

[0111] The nonpolar group in the general formula (1) is preferably any of an alkyl group, an aryl group, a cycloalkyl group, a phenyl group, an alkenyl group, an aralkyl group, a cycloalkenyl group, an alkynyl group, a silyl group, and a siloxane group. It should be noted that the nonpolar group does not contain a hydrogen atom.

[0112] In particular, from the viewpoint of improving the flexibility of the ablation layer 2 and ensuring the close adhesion with the substrate 1, in the above general formula (1), it is more preferred that R1 and R2 are each independently selected from the group consisting of alkyl, alkenyl and alkynyl groups, and from the viewpoint of low polarity, an alkyl group is further preferred.

[0113] The monomers that can form the structural unit represented by the general formula (1) are not limited to the following monomers, and examples thereof include: isobutylene, 2-methyl-2-butene, 2,3-dimethyl-2-butene, and substances obtained by replacing the methyl groups of these with other alkyl groups such as ethyl groups, and their modified products; α-methylstyrene, cis-(1-methyl-1-propenyl)benzene, trans-(1-methyl-1-propenyl)benzene, and substances obtained by replacing the methyl groups of these with other alkyl groups such as ethyl groups, and their modified products; 1,1-diphenylethylene, etc.

[0114] In the above general formula (1), R3 and R4 each independently represent a hydrogen atom or a non-polar group.

[0115] R3 and R4 are each independently preferably any one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an alkynyl group, and more preferably a hydrogen atom or an alkyl group. If both R3 and R4 are hydrogen atoms, the depolymerization property of the resin is further improved, which is further preferred.

[0116] In addition, the structural unit (1) represented by the general formula (1) constituting the resin may be a single type or may be two or more types. For example, as the structural unit (1), the resin may have a structural unit in which R1 and R2 are alkyl groups, and a structural unit in which one of R1 and R2 is an alkyl group and the other is a phenyl group. By having both an alkyl group and a phenyl group, the characteristics of these two groups can be obtained.

[0117] The resin contained in the ablation layer 2 preferably contains a structural unit (2) derived from a monovinyl-substituted aromatic hydrocarbon in addition to the structural unit (1).

[0118] The monovinyl aromatic hydrocarbon can be chemically bonded to the structural unit (1) represented by the above general formula (1) or added as a different resin, but from the viewpoint of dispersibility and the resulting uniformity of laser processing, the structural unit (2) derived from the monovinyl-substituted aromatic hydrocarbon is preferably chemically bonded to the structural unit (1) represented by the above general formula (1) to form a copolymer.

[0119] When the resin used in the ablation layer contains the structural unit (2) derived from a monovinyl-substituted aromatic hydrocarbon, the adhesion between the ablation layer 2 and the substrate 1 is improved, and the rigidity of the film for producing a flexographic printing plate of the present embodiment tends to be improved.

[0120] The compound for forming the structural unit (2) derived from a monovinyl aromatic hydrocarbon is not limited to the following, and examples thereof include monomers such as styrene, tert-butylstyrene, N,N-dimethyl-p-aminoethylstyrene, N,N-diethyl-p-aminoethylstyrene, vinylpyridine, p-methylstyrene, and tert-butylstyrene. In particular, styrene is preferred from the viewpoint of being able to smoothly form the film for manufacturing a flexographic printing plate of the present embodiment at a relatively low temperature.

[0121] The structural unit (2) may be present in one type or in two or more types.

[0122] <Infrared absorbing substances>

[0123] The ablation layer 2 may contain an infrared absorbing substance for ablation processing. Examples of the infrared absorbing substance generally include a monomer or a compound having strong absorption in the range of 750 to 2000 nm.

[0124] Infrared absorbing substances are not limited to the following substances, for example, inorganic pigments such as carbon black, graphite, copper chromite, and chromium oxide; pigments such as polyphthalocyanine compounds, cyanine pigments, and metal thiolate pigments. The smaller the particle size, the higher the sensitivity to infrared lasers. In particular, carbon black can be used in a wide range of particle sizes of 13 to 85 nm, and is preferred as an infrared absorbing substance. In addition, carbon black can also function as the following shielding substance. These infrared absorbing substances are added within a range of sensitivity that can be removed by the laser light used.

[0125] <Shielding Material>

[0126] The ablation layer 2 functions as a mask, and therefore may contain a non-infrared shielding material such as ultraviolet rays. As the non-infrared shielding material, a material that reflects or absorbs ultraviolet light may be used.

[0127] Examples of the shielding substance include, but are not limited to, ultraviolet absorbers, carbon black, and graphite.

[0128] <Thickness of Ablation Layer>

[0129] The ablative layer 2 of the film for producing a flexographic printing plate of the present embodiment is preferably thicker from the viewpoint of ensuring shielding properties against ultraviolet rays in an exposure step described later, and is preferably thinner from the viewpoint of improving ablative properties.

[0130] From the above viewpoints, the film thickness of the ablation layer 2 is preferably 0.1 μm to 20 μm, more preferably 0.5 μm to 15 μm, and even more preferably 1.0 μm to 10 μm.

[0131] As for the non-infrared shielding effect of the ablation layer 2 , the optical density of the ablation layer 2 is preferably 2 or more, and more preferably 3 or more.

[0132] The optical density can be measured using a D200-II transmission densitometer (manufactured by Gretag Macbeth). The optical density is a so-called visual perception (ISO visual), and the light to be measured is in the wavelength region of about 400 to 750 nm.

[0133] [Method for producing film for producing flexographic printing plates]

[0134] The method for producing the film for producing a flexographic printing plate according to the present embodiment is not limited to the following. For example, when carbon black is used as both an infrared absorbing substance and a non-infrared shielding substance, first, a solution of a resin having the structural unit (1) represented by the general formula (1) is prepared using a predetermined solvent, and carbon black and a dispersant are added thereto to disperse the carbon black in the resin solution, thereby obtaining a solution or dispersion for forming the ablation layer 2. Then, a method for producing the film by coating the solution or dispersion for forming the ablation layer on a predetermined substrate 1 can be cited.

[0135] As a method for dispersing carbon black in the solution of the above-mentioned resin, a method of combining forced stirring by a stirring blade with stirring using ultrasonic waves or various mills is effective. Alternatively, a method of pre-mixing the resin, carbon black and a dispersant using an extruder or a kneader and then dissolving them in a solvent is also an effective method for obtaining good dispersibility of carbon black. In addition, a method of forcibly dispersing carbon black in a resin in a state of a latex dispersion can also be cited.

[0136] The solvent used in preparing the solution, dispersion, etc. for forming the ablative layer 2 can be appropriately selected in consideration of the solubility of the resin or infrared absorber used. Only one type of solvent may be used, or two or more types of solvents may be mixed and used.

[0137] In addition, for example, by mixing a solvent with a relatively low boiling point and a solvent with a high boiling point and controlling the volatilization rate of the solvent, the film quality of the ablation layer 2 can also be improved.

[0138] The solvent used for forming the ablation layer 2 is not limited to the following, for example, toluene, xylene, cyclohexane, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, methyl ethyl ketone, acetone, cyclohexanone, ethylene glycol, propylene glycol, ethanol, water, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylacetamide, dimethylformamide, n-propanol, isopropanol, 1,4-dioxane, tetrahydrofuran, diethyl ether, n-hexane, n-heptane, n-pentane and acetonitrile and the like.

[0139] [Laminated body]

[0140] The laminated body of the present embodiment has a configuration in which a flexographic printing plate having a photosensitive resin composition layer and the film for producing a flexographic printing plate of the present embodiment described above are laminated on the flexographic printing plate.

[0141] The flexographic printing plate includes a support and a photosensitive resin composition layer laminated on the support.

[0142] As described later, the flexographic printing plate is subjected to pattern exposure to form a relief, and the unexposed portion is removed by development to obtain a target flexographic printing plate.

[0143] (Supporting body)

[0144] Examples of the support of the printing plate include, but are not limited to, polyester films, polyamide films, polyacrylonitrile films, and polyvinyl chloride films.

[0145] Among them, a polyester film is preferable as the support.

[0146] The polyester used for the support is not limited to the following, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0147] The thickness of the support is not particularly limited, but is preferably 50 to 300 μm.

[0148] In addition, for the purpose of improving the adhesive force between the support and the photosensitive resin composition layer described later, a predetermined adhesive layer may be provided on the support. The adhesive layer is not particularly limited, and examples thereof include adhesive layers described in International Publication No. 2004 / 104701, Japanese Patent No. 3094647, and Japanese Patent No. 2634429.

[0149] (Photosensitive resin composition layer)

[0150] The above-mentioned printing original plate has a photosensitive resin composition layer on a support.

[0151] The photosensitive resin composition layer may be directly laminated on the support, or may be laminated indirectly via a predetermined adhesive layer or the like.

[0152] The photosensitive resin composition layer preferably contains, for example, a polymer (b-1), an ethylenically unsaturated compound (b-2), and a photopolymerization initiator (b-3) which will be described later. These can be used selectively as appropriate.

[0153] In addition, the photosensitive resin composition layer may further contain auxiliary additive components as necessary.

[0154] Hereinafter, each component of the photosensitive resin composition layer will be described in detail.

[0155] <Polymer (b-1)>

[0156] The polymer (b-1) may be any of a linear, branched or dendritic polymer, and may be a homopolymer or a copolymer. The copolymer may be a random copolymer, an alternating copolymer or a block copolymer.

[0157] Examples of the polymer (b-1) include fully or partially hydrolyzed polyvinyl esters, partially hydrolyzed polyvinyl acetates, polyvinyl alcohol derivatives, partially hydrolyzed vinyl acetate / oxyalkylene graft copolymers, or polyvinyl alcohols that have been subsequently acrylated by a polymer-analogous reaction, polybutadiene, polyamides, and mixtures thereof, which are polymers that have been used in the manufacture of flexographic printing plates.

[0158] In addition to the above, for example, a thermoplastic elastomer block copolymer may be used.

[0159] As the thermoplastic elastomer block copolymer, there can be mentioned a block copolymer having at least one block containing alkenyl aromatic monomer units and at least one block containing 1,3-diene monomer units. As the alkenyl aromatic compound forming the alkenyl aromatic monomer units, for example, styrene, α-methylstyrene, or vinyltoluene can be mentioned. As the 1,3-diene, from the viewpoint of reducing the steric hindrance of the vinyl group, improving the efficiency of photocrosslinking, and preventing the ablation layer from eluting into the printing original plate after exposure, for example, butadiene and isoprene are preferred.

[0160] Furthermore, the polymer (b-1) preferably contains a compound having a carbonyl group. By using a compound having a highly polar carbonyl group as the polymer (b-1), the compatibility with the resin having a non-polar group in the ablation layer can be reduced, and the tendency of the ablation layer to dissolve into the photosensitive resin composition layer can be suppressed.

[0161] The polymer (b-1) is not limited to the following, and examples thereof include polyester, polyamide, and polyurethane. Polyurethane is more preferably included from the viewpoint of preventing damage to the relief surface due to the load when the film for manufacturing a flexographic printing plate is peeled off after the exposure step. Furthermore, from the viewpoint of improving the mechanical properties of the flexographic printing plate finally obtained by photocrosslinking, the polyurethane preferably has a (meth)acryloyl group at the terminal group.

[0162] As a method for producing a polyurethane having a (meth)acryloyl group at the terminal group, for example, there can be mentioned a method in which a diol having a repeating unit in the molecule is reacted with a diisocyanate to form a polyurethane having an isocyanate group at the terminal of any molecular weight, and then the polyurethane is reacted with a compound containing active hydrogen and a (meth)acryloyl group in one molecule. In addition, there can be mentioned a method in which a diol having a repeating unit in the molecule is reacted with a diisocyanate to form a polyurethane having an isocyanate group at the terminal of any molecular weight, and then the polyurethane is reacted with a compound containing a hydroxyl group and a (meth)acryloyl group in one molecule.

[0163] The polyurethane structure obtained by the above-mentioned production method is a structure constituted by the reaction of a diol having a repeating unit in a molecule and a diisocyanate.

[0164] Hereinafter, the “polyurethane having a (meth)acryloyl group at a terminal group” produced by the above method is described as an “unsaturated prepolymer”.

[0165] The "diol having a repeating unit in the molecule" used to produce the unsaturated prepolymer is not limited to the following, and examples thereof include polyester diol formed from dicarboxylic acid and diol; polyether diol; polyether polyester copolymer diol; 1,2-polybutadiene compound having a terminal hydroxyl group, etc. The diol having a repeating unit in the molecule may be used alone or in combination of two or more.

[0166] Examples of the dicarboxylic acid constituting the polyester diol include, but are not limited to, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, terephthalic acid, isophthalic acid, and 1,5-naphthalene dicarboxylic acid.

[0167] Examples of the diol constituting the polyester diol include, but are not limited to, 1,4-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, and diethylene glycol (dioxyethylene glycol).

[0168] Examples of the polyether diol include, but are not limited to, polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, polyoxybutylene glycol, polyoxyethylene / polyoxypropylene random copolymer diol, polyoxyethylene / polyoxypropylene block copolymer diol, polyoxyethylene / polyoxytetramethylene random copolymer diol, and polyoxyethylene / polyoxytetramethylene block copolymer diol.

[0169] Examples of the polyether polyester copolyol include, but are not limited to, copolymers having a structure in which repeating units forming the molecular chain of the polyether diol and repeating units forming the molecular chain of the polyester diol are block- or randomly chained.

[0170] The 1,2-polybutadiene compound having a terminal hydroxyl group may be a hydrogenated compound. The 1,2-polybutadiene compound having a terminal hydroxyl group is not limited to the following, and examples thereof include hydrogenated poly-1-butene and hydrogenated 1,2-polybutadiene. Although not particularly limited, from the viewpoint of preventing damage to the relief surface caused by the load when peeling off the printing plate manufacturing film after exposure, the number of terminal hydroxyl groups per molecule is preferably 1.2 or more, more preferably 1.5 or more, and further preferably 2.0 or less.

[0171] Examples of the diisocyanate include, but are not limited to, toluene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, and norbornene diisocyanate.

[0172] The diisocyanate may be used alone or in combination of two or more.

[0173] <Ethylenically Unsaturated Compound (b-2)>

[0174] As described above, the photosensitive resin composition layer preferably contains an ethylenically unsaturated compound (b-2). The ethylenically unsaturated compound (b-2) is a compound having an unsaturated double bond that can undergo radical polymerization.

[0175] The ethylenically unsaturated compound (b-2) is not limited to the following, and examples thereof include olefins such as ethylene, propylene, vinyltoluene, styrene, and divinylbenzene; acetylenes; (meth)acrylic acid and / or its derivatives; halogenated olefins; unsaturated nitriles such as acrylonitrile; unsaturated amides such as acrylamide or methacrylamide and their derivatives; unsaturated dicarboxylic acids such as maleic anhydride, maleic acid, and fumaric acid and their derivatives; vinyl acetates; N-vinyl pyrrolidone; N-vinyl carbazole; N-substituted maleimide compounds, etc.

[0176] The above-mentioned derivatives are not limited to the following, for example, alicyclic compounds having cycloalkyl, bicycloalkyl, cycloalkenyl, bicycloalkenyl, etc.; aromatic compounds having benzyl, phenyl, phenoxy, or naphthalene skeleton, anthracene skeleton, biphenyl skeleton, phenanthrene skeleton, fluorene skeleton, etc.; compounds having alkyl, halogenated alkyl, alkoxyalkyl, hydroxyalkyl, aminoalkyl, glycidyl, etc.; ester compounds with polyols such as alkylene glycol, polyoxyalkylene glycol, polyalkylene glycol, trimethylolpropane, etc.; compounds having a polysiloxane structure such as polydimethylsiloxane and polydiethylsiloxane, etc.

[0177] Furthermore, the ethylenically unsaturated compound (b-2) may be a heteroaromatic compound containing elements such as nitrogen and sulfur.

[0178] The above-mentioned (meth)acrylic acid and / or its derivatives are not limited to the following, and examples thereof include 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 butanediol; trimethylolpropane tri(meth)acrylate; dimethyloltricyclodecane di(meth)acrylate; isobornyl (meth)acrylate; phenoxypolyethylene glycol (meth)acrylate; pentaerythritol tetra(meth)acrylate, etc.

[0179] These may be used alone or in combination of two or more.

[0180] From the viewpoint of improving the strength of the flexographic printing plate and preventing damage to the relief surface due to the load when the flexographic printing plate manufacturing film of this embodiment is peeled off after exposure, it is preferred to use at least one (meth)acrylate as the ethylenically unsaturated compound (b-2), and it is more preferred to use at least one bifunctional (meth)acrylate.

[0181] <Photopolymerization Initiator (b-3)>

[0182] The photosensitive resin composition layer preferably contains a photopolymerization initiator (b-3).

[0183] The photopolymerization initiator (b-3) is a compound that absorbs light energy to generate free radicals, and examples thereof include cleavage-type photopolymerization initiators, hydrogen abstraction-type photopolymerization initiators, and compounds having a site that functions as a hydrogen abstraction-type photopolymerization initiator and a site that functions as a cleavage-type photopolymerization initiator in the same molecule.

[0184] Such a photopolymerization initiator (b-3) is not limited to the following, and examples thereof include benzophenones such as benzophenone, 4,4-bis(diethylamino)benzophenone, 3,3',4,4'-benzophenonetetracarboxylic anhydride, and 3,3',4,4'-tetramethoxybenzophenone; anthraquinones such as tert-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-phenylpropane-1-one, benzyl dimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propane- Acetophenones such as 1-keto, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, and trichloroacetophenone; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; acyl phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; methyl benzoylformate; 1,7-bisacridinylheptane; 9-phenylacridine; azo compounds such as azobisisobutyronitrile, diazo compounds, and tetrazene compounds.

[0185] These may be used alone or in combination of two or more.

[0186] From the viewpoint of preventing the final flexographic printing plate from being damaged and preventing the embossed surface from being damaged due to the load when the film for printing plate manufacturing of this embodiment is peeled off after exposure, when the total amount of the photosensitive resin composition layer is set to 100 mass %, the content of the photopolymerization initiator (b-3) in the photosensitive resin composition layer is preferably 0.1 mass % to 10 mass %, more preferably 0.1 mass % to 5 mass %, and further preferably 0.3 mass % to 5 mass %.

[0187] <Auxiliary additives>

[0188] The auxiliary additive components are not limited to the following, and examples thereof include plasticizers, thermal polymerization inhibitors, antioxidants, light stabilizers, ultraviolet absorbers, dyes and / or pigments.

[0189] The plasticizer is not limited to the following, and examples thereof include liquid dienes such as liquid polybutadiene, liquid polyisoprene, modified liquid polybutadiene, modified liquid polyisoprene, liquid acrylonitrile-butadiene copolymer, and liquid styrene-butadiene copolymer; hydrocarbon oils such as cycloparaffin oil and paraffin oil; conjugated diene rubbers mainly composed of liquid dienes such as liquid acrylonitrile-butadiene copolymer and liquid styrene-butadiene copolymer; polystyrene having a number average molecular weight of less than 2,000; and ester plasticizers such as sebacic acid ester and phthalic acid ester.

[0190] These plasticizers may have a hydroxyl group or a carboxyl group. In addition, these plasticizers may be provided with a photopolymerizable reactive group such as a (meth)acryloyl group. The above plasticizers may be used alone or in combination of two or more.

[0191] It should be noted that the "liquid state" in this specification refers to a state having the property of being able to flow and deform easily and being able to solidify into a deformed shape by cooling.

[0192] From the viewpoint of improving the flexibility of the obtained flexible printing original plate, preventing damage to the ablation layer when the thin film for printing plate manufacturing of this embodiment is peeled off after exposure, and preventing dissolution into the photosensitive resin composition layer, when the total amount of the photosensitive resin composition layer is set to 100 mass%, the content of the plasticizer in the photosensitive resin composition layer is preferably 0 mass% to 30 mass%, more preferably 8 mass% to 30 mass%, and further preferably 8 mass% to 25 mass%.

[0193] As the thermal polymerization inhibitor and the antioxidant, those generally used in the field of resin materials or rubber materials can be used, and examples thereof include phenol-based materials.

[0194] The phenolic materials used as the thermal polymerization inhibitor and the antioxidant are not limited to the following, and examples thereof include vitamin E, tetrakis-(methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate)methane, 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butyl-p-cresol, 3,9-bis-{1,1-dimethyl-2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro(5,5)undecane, and 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate.

[0195] As other thermal polymerization inhibitors and antioxidants, for example, phosphine-based materials such as triphenyl phosphite can be mentioned.

[0196] The thermal polymerization inhibitor and the antioxidant may be used alone or in combination of two or more.

[0197] The light stabilizer and ultraviolet absorber are not limited to the following, and examples thereof include known benzophenone compounds, salicylate compounds, acrylonitrile compounds, metal complex salt compounds, and hindered amine compounds.

[0198] In addition, dyes and / or pigments described below may also be used as ultraviolet absorbers.

[0199] Examples of such light stabilizers and ultraviolet absorbers include, but are not limited to, 2-ethoxy-2′-ethyloxalanilide, 2,2′-dihydroxy-4-methoxybenzophenone, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-sebacate, and 1,2,3-benzotriazole.

[0200] Dyes and / or pigments are effective as coloring means for improving visibility.

[0201] Examples of dyes include, but are not limited to, water-soluble basic dyes, acid dyes, direct dyes, and water-insoluble sulfur dyes, oil-soluble dyes, and disperse dyes. Anthraquinone dyes, indigo dyes, and azo dyes are particularly preferred.

[0202] The pigment is not limited to the following pigments, and examples thereof include 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.

[0203] [Method for producing flexographic printing plate]

[0204] Hereinafter, a preferred embodiment of the method for producing a flexographic printing plate according to the present embodiment will be described.

[0205] In addition, the manufacturing method of the flexographic printing plate of this embodiment is not limited to the following form.

[0206] The method for producing a flexographic printing plate according to the present embodiment uses the laminated body according to the present embodiment described above.

[0207] As described above, the laminate has a structure in which a flexographic printing original plate having a photosensitive resin composition layer and the film for producing a flexographic printing plate of the present embodiment are laminated.

[0208] The manufacturing method of the flexographic printing plate of the present embodiment comprises: a drawing step, in which infrared rays are irradiated to the film for manufacturing the flexographic printing plate to draw a processing pattern; an exposure step, in which the ablation layer having the pattern drawn in the drawing step is used as a mask to irradiate the photosensitive resin composition layer with ultraviolet rays to form a pattern; and a development step, in which the unexposed portion of the photosensitive resin composition layer is removed.

[0209] In the step of drawing the printing pattern in the method for producing a flexographic printing plate of the present embodiment, the target of infrared irradiation may be the flexographic printing plate production film constituting the laminate or the flexographic printing plate production film before constituting the laminate.

[0210] That is, the film for producing a flexographic printing plate constituting the laminate of the present embodiment includes both a form before pattern drawing and a form after pattern drawing.

[0211] In more detail, the method for manufacturing a flexible printing plate of the present embodiment comprises: first, a step of irradiating ultraviolet rays from the support body side of the flexible printing original plate constituting the laminate of the present embodiment (a first step); a drawing step of irradiating infrared rays to the ablation layer of the film for manufacturing the flexible printing plate to draw a processing pattern (a second step); an exposure step of using the ablation layer with the drawn processing pattern as a mask to irradiate ultraviolet rays to the photosensitive resin composition layer to form a pattern (a third step); and a development step of removing the unexposed portion of the photosensitive resin composition layer (a fourth step).

[0212] Then, a post-exposure treatment step is performed as necessary to obtain a flexographic printing plate formed of a cured product of the photosensitive resin composition layer.

[0213] In the above-mentioned method for producing a flexographic printing plate, the film for producing a flexographic printing plate constituting the laminate in the second step is in a state before pattern drawing, and the film for producing a flexographic printing plate constituting the laminate in the third step is in a state after pattern drawing.

[0214] From the viewpoint of imparting releasability, the surface of the flexographic printing plate may be brought into contact with a liquid containing an organic silicon compound and / or a fluorine compound.

[0215] Figure 2 A schematic diagram showing a method for producing a flexographic printing plate using the film for producing a flexographic printing plate according to the present embodiment is shown. Each step will be described in detail below.

[0216] (First process)

[0217] In the first step, the photosensitive resin composition layer 4 is irradiated with ultraviolet rays from the support 3 side of the flexographic printing plate.

[0218] The ultraviolet irradiation method is not particularly limited, and a known irradiation unit can be used. The wavelength of the ultraviolet irradiation is preferably 150 to 500 nm, more preferably 300 to 400 nm.

[0219] The light source of ultraviolet rays is not limited to the following light sources, and for example, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, a xenon lamp, a zirconium lamp, a carbon arc lamp, and an ultraviolet fluorescent lamp can be used.

[0220] It should be noted that the first step may be performed before the second step described later, or may be performed after the second step.

[0221] (Second process)

[0222] In the second step, the ablation layer 2 of the film for manufacturing a flexographic printing plate is irradiated with infrared rays to draw a pattern. The drawing method is not particularly limited, and it can be performed using a known irradiation unit. It should be noted that the irradiation of the ablation layer 2 with infrared rays can be performed from the ablation layer 2 side.

[0223] The ablation layer 2 is pattern-irradiated with infrared rays to decompose the resin in the infrared-irradiated area and draw the pattern. Thus, a mask of the ablation layer is formed on the film for manufacturing a flexographic printing plate. Thus, the ablation layer 2' with the pattern drawn is obtained.

[0224] As the infrared laser used in the second step, for example, ND / YAG laser (for example, 1064 nm) or diode laser (for example, 830 nm) can be cited. Laser systems suitable for CTP platemaking technology are commercially available, for example, the diode laser system CDI Spark (ESKO GRAPHICS) can be used. The laser system includes a rotating cylindrical drum that holds a film for manufacturing a flexible printing plate, an IR laser irradiation device and a layout computer, and image information is directly sent from the layout computer to the laser device.

[0225] In the method for producing a flexographic printing plate of the present embodiment, the second step may be performed after the flexographic printing plate-producing film and the photosensitive resin composition layer are laminated, or before laminating the photosensitive resin composition layer.

[0226] (Third process)

[0227] In the third step, the photosensitive resin composition layer 4 is irradiated with ultraviolet rays using the patterned ablation layer 2 ′ as a mask to perform pattern exposure.

[0228] At this time, the light from the mask promotes the curing reaction of the photosensitive resin composition layer 4, and the concavoconvexity of the pattern formed on the ablation layer 2' is reversed and transferred to the photosensitive resin composition layer 4, thereby obtaining a pattern-exposed photosensitive resin composition layer 4'. The ultraviolet irradiation may be performed on the entire surface or partially.

[0229] The front and back surfaces of the flexographic printing plate manufacturing film of this embodiment can be used without particular limitation, but from the viewpoint of reducing the influence of refraction and scattering of ultraviolet light irradiated on the photosensitive resin composition layer, the surface on the side of the patterned ablation layer 2' on the flexographic printing plate manufacturing film is preferably arranged in contact with the photosensitive resin composition layer.

[0230] On the other hand, for the purpose of protecting or surface treating the photosensitive resin composition layer, a separate film may be provided between the patterned film for producing a flexographic printing plate and the photosensitive resin composition layer 4 .

[0231] Furthermore, one or more intermediate layers may be further provided between the photosensitive resin composition layer 4 and the ablation layer 2'. The intermediate layer is not limited to the following, and examples thereof include an oxygen barrier layer, an adhesive layer, and a protective layer.

[0232] Each layer is described below.

[0233] In order to produce printed materials with high definition and high brightness, it is necessary to form tiny dots on a flexographic printing plate. From the viewpoint of forming such tiny dots, the intermediate layer is preferably an oxygen barrier layer having oxygen barrier capability.

[0234] If the radical polymerization reaction when the photosensitive resin composition layer 4 is cured by ultraviolet irradiation is inhibited by oxygen, there is a concern that an unreacted portion may remain in the exposed portion of the photosensitive resin composition layer 4. The unreacted portion is removed in the fourth step described later, so the pattern finally formed on the flexographic printing plate has a curved portion at the front end. This is because the portion of the photosensitive resin composition layer 4 on the ablation layer 2' side is particularly susceptible to the inhibition caused by oxygen, and an unreacted portion is easily generated in the photosensitive resin composition layer 4 located directly below the ablation layer 2'.

[0235] On the other hand, if the coexistence of oxygen is reduced during ultraviolet curing, the polymerization reaction is difficult to be suppressed, and the pattern finally formed becomes a shape having a flat portion at the front end. Therefore, when it is desired to produce a pattern having a flat portion at the front end, the intermediate layer preferably has oxygen barrier capability, thereby reducing the oxygen in contact with the photosensitive resin composition layer 4.

[0236] Alternatively, the intermediate layer may be an adhesive layer that improves the adhesiveness between the photosensitive resin composition layer 4 and the ablation layer 2 ′.

[0237] Furthermore, the intermediate layer may also have the function of protecting the ablation layer 2'. In the manufacturing process of the flexographic printing plate, there is a concern that the ablation layer 2' may be physically damaged by contact with the operator's fingers and jigs when laminating the photosensitive resin composition layer 4 on the film for manufacturing the flexographic printing plate or during film handling, thereby generating scratches and pinholes.

[0238] In order to prevent such damage to the ablation layer 2 ′, the intermediate layer preferably has physical strength and heat resistance as a protective layer.

[0239] (Fourth process)

[0240] The fourth step is a step of removing the unexposed portion of the photosensitive resin composition layer 4 ′ subjected to pattern exposure.

[0241] The method for removing the unexposed portion in the fourth step (development step) is not particularly limited, and a conventionally known method can be used.

[0242] As a specific method, for example, the following methods can be cited: a method of exposing the photosensitive resin composition layer 4, and then washing the unexposed portion with a solvent for solvent development or a cleaning solution for water development; or a method of contacting with a predetermined absorption layer that can absorb the unexposed portion, removing the absorption layer, and thus removing the unexposed portion. It should be noted that as a pre-process for removal, a scraper or a roller can also be used to remove the unexposed portion in advance. Then, a post-exposure treatment is performed as needed, thereby manufacturing a flexographic printing plate.

[0243] In addition, when there is an intermediate layer between the ablation layer 2' and the photosensitive resin composition layer 4', it can remove them simultaneously in the development process.

[0244] When the photosensitive resin composition is liquid at room temperature, the first to third steps generally include a predetermined molding step in which the photosensitive resin composition is molded into a film having a certain thickness on a support inside a dedicated device (plate-making machine).

[0245] As described above, in the exposure step when a liquid photosensitive resin composition is used at room temperature, for example, each of the following steps (A1) to (A3) is preferably performed.

[0246] (A1):

[0247] In step (A1), a film for manufacturing a flexible printing plate on which a mask is formed by drawing a pattern is placed on an ultraviolet-transmissive glass plate (lower glass plate), a photosensitive resin composition is flowed thereon, and a base film serving as a support is bonded via a spacer so that the photosensitive resin composition has a certain plate thickness, and then a ultraviolet-transmissive glass plate (upper glass plate) is pressed therefrom to form a photosensitive resin composition layer.

[0248] In the step (A1), after placing the film for manufacturing a flexographic printing plate on the lower glass plate, the film is preferably evacuated for the purpose of reliably fixing the film for manufacturing a flexographic printing plate and removing oxygen inhibitors. The mechanism of evacuation is not particularly limited, and an example thereof is a method of evacuating the film by a pump through a groove provided around the lower glass.

[0249] If the rigidity of the flexographic printing plate manufacturing film is insufficient, wrinkles will be generated in the flexographic printing plate manufacturing film during the vacuuming process, and in severe cases, the wrinkles cannot be removed and remain. The generated wrinkles are transferred to the relief surface after curing, which may significantly reduce the image reproducibility. In addition, if the dimensional stability of the flexographic printing plate manufacturing film is insufficient, the pattern drawn and processed will be deformed, which will also become a cause of reducing the image reproducibility.

[0250] On the other hand, when the rigidity of the above-mentioned flexible printing plate manufacturing film is too high, it cannot completely follow the lower glass during vacuuming and there is a gap, and air remains. As a result, the influence of oxygen barrier becomes larger, and there is a concern that it will have an adverse effect on image reproducibility. In addition, there is a concern that the stress generated by the deformation of the highly elastic flexible printing plate manufacturing film is concentrated on the ablation layer, resulting in wrinkles and pinholes. That is, it is extremely important that the flexible printing plate manufacturing film of this embodiment has a rigidity within an appropriate range.

[0251] In addition, you may provide another film between the film for manufacturing a flexographic printing plate on which a pattern is drawn and processed and the photosensitive resin composition.

[0252] When manufacturing a flexographic printing plate (thickness of 4 mm or more) for corrugated paper printing, in order to compensate for the relief strength relative to the printing pressure during printing, it is preferred to form a shelf layer that serves as a base on the portion of the photosensitive resin composition layer on the upper glass plate side. In this case, before the relief exposure, a dedicated negative film (masking film) is sandwiched between the upper glass plate and the base film to form the photosensitive resin composition layer.

[0253] (A2):

[0254] In step (A2), after the step of forming the photosensitive resin composition layer, active light (for example, light having a wavelength distribution of more than 300 nm) using an ultraviolet fluorescent lamp or the like as an active light source is irradiated from the upper glass plate side through the base film, thereby performing back exposure to precipitate a uniform thin cured resin layer (i.e., a bottom forming layer (back precipitation layer)) on the entire surface of the base film side of the plate.

[0255] When a masking film is provided in the photosensitive resin composition layer forming step, the shelf layer is formed by the same exposure. In this case, it is called a masking exposure step.

[0256] The back precipitation layer and the shelf layer are both formed by curing the photosensitive resin composition layer on the side opposite to the relief forming layer, i.e., the support side. When the entire photosensitive resin composition layer on the support side is cured, it becomes the back precipitation layer, and when the photosensitive resin composition layer is partially cured according to the position of the relief forming layer, it becomes the shelf layer.

[0257] (A3):

[0258] In step (A3), after the back exposure step or the mask exposure step, the photosensitive resin composition layer is irradiated with the same active light as in the above-mentioned (A2) from the lower glass side through a film for manufacturing a flexible printing plate on which a mask is formed by drawing a pattern, so that an image forming layer (relief forming layer) is precipitated, and relief forming exposure is performed.

[0259] It should be noted that, when the shelf layer is formed by a masking exposure step, it is also a preferred embodiment to remove the masking film after the relief forming exposure and then perform a back exposure step to form a back deposition layer on the entire surface of the base film.

[0260] (Recovery and Recycling of the Photosensitive Resin Composition in the Unexposed Part)

[0261] In the method for producing a flexographic printing plate of the present embodiment, a recovery step may be performed to recover the photosensitive resin composition of the unexposed portion removed in the development step as a photosensitive resin composition for producing a new flexographic printing plate. The recovered photosensitive resin composition can be reused as a photosensitive resin composition for producing a new flexographic printing plate.

[0262] The recovered photosensitive resin composition can be put into an exposure machine when manufacturing a new flexographic printing plate. When the photosensitive resin composition is processed and formed before exposure, the recovered photosensitive resin composition can be used in the processing and forming step.

[0263] The exposure machine into which the recovered photosensitive resin composition is introduced refers to an exposure machine equipped with a unit in which a support and a photosensitive resin composition are laminated in a layered form, and when the photosensitive resin composition is filled in the unit, the recovered photosensitive resin composition can be used.

[0264] By using the recycled photosensitive resin composition, waste can be reduced and material costs can also be reduced. On the other hand, if a large amount of the ablation layer is dissolved or transferred to the recycled photosensitive resin composition, various disadvantages such as scattering of active light may occur in the flexographic printing plate manufacturing process using the recycled photosensitive resin composition, and there is a concern that the quality of the finally obtained flexographic printing plate may be impaired.

[0265] By using the film for manufacturing a flexographic printing plate of the present embodiment, in the finally obtained flexographic printing plate, the elution and transfer of the ablation layer to the photosensitive resin composition layer are suppressed, so that the photosensitive resin composition having the same quality as that before use can be recovered at a high yield. Therefore, even in a new flexographic printing plate manufactured using the recovered photosensitive resin composition, the quality of the improved hollow depth can be maintained.

[0266] Specifically, the method for producing a flexographic printing plate according to the present embodiment has the following effects (1) to (4).

[0267] (1) The elution and transfer of the ablation layer to the obtained flexographic printing plate and flexographic printing original plate can be reduced.

[0268] (2) By setting the substrate thickness of the film for producing a flexographic printing plate within an appropriate range, a flexographic printing plate having excellent image reproducibility and hollow depth can be easily produced.

[0269] (3) In the development step, the unexposed photosensitive resin composition with reduced deterioration and contamination can be removed and recovered, thereby preventing the photosensitive resin composition from being deteriorated and allowing the high-quality photosensitive resin composition to be reused at a high yield.

[0270] (4) In the development step, it is possible to suppress the mixing of impurities into the unexposed photosensitive resin composition, and thus it is possible to select a development method from a wide range.

[0271] Example

[0272] 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 at all.

[0273] [Film for manufacturing flexographic printing plates and manufacturing of flexographic printing plates]

[0274] In the following Examples and Comparative Examples, a film for producing a flexographic printing plate was prepared, and a flexographic printing plate was produced using the film for producing a flexographic printing plate.

[0275] ((1) Production of resin for ablative layer)

[0276] <Manufacturing of Resin 1>

[0277] After nitrogen substitution in the polymerization container of a 2L separable flask, 456.1 mL of n-hexane (dried with molecular sieves) and 656.5 mL of butyl chloride (dried with molecular sieves) were added using a syringe, and the polymerization container was immersed in a dry ice / methanol bath at -70°C for cooling. A liquid delivery tube made of Teflon (registered trademark) was connected to a pressure-resistant glass liquefaction collection tube with a three-way stopcock to which 161.1 g (2871 mmol) of isobutylene monomer was added, and the isobutylene monomer was delivered to the polymerization container by nitrogen pressure. 0.647 g (2.8 mmol) of p-dicumyl chloride and 1.22 g (14 mmol) of N,N-dimethylacetamide were added. Subsequently, 8.67 mL (79.1 mmol) of titanium tetrachloride was further added to start polymerization.

[0278] After stirring at the same temperature for 1.5 hours from the start of polymerization, about 1 mL of the polymerization solution was taken out from the polymerization solution for sampling.

[0279] Next, a mixed solution of 77.9 g (748 mmol) of styrene monomer, 23.9 mL of n-hexane and 34.3 mL of butyl chloride previously cooled to -70°C was added to the polymerization container. 45 minutes after the addition of the mixed solution, about 40 mL of methanol was added to terminate the reaction, thereby obtaining a reaction solution.

[0280] After the solvent and the like were distilled off from the reaction solution, the solution was dissolved in toluene and washed twice with water. The toluene solution was then added to a large amount of methanol to precipitate a polymer, and the obtained polymer was vacuum dried at 60° C. for 24 hours, thereby obtaining a resin 1.

[0281] pass 1 The content of the structural unit derived from styrene was determined by H-NMR and found to be 30% by mass.

[0282] <Manufacturing of Resins 2 to 6>

[0283] The types of monomers used to form the structural unit 1 and structural unit 2 of the resin were changed as shown in the following Table 1. Resins 2 to 6 were obtained in the same manner as in Resin 1 under other conditions.

[0284] The following Table 1 shows the composition of the resin.

[0285] <Manufacturing of Resin 7>

[0286] 2 kg of water, 65 g of calcium phosphate, 40 g of calcium carbonate, and 0.40 g of sodium lauryl sulfate were added to a container with a stirrer to obtain a mixed solution. Next, 25 kg of water was added to a 60 L reactor, the temperature was raised to 80° C., and the mixed solution, 21.5 kg of methyl methacrylate, 110 g of lauroyl peroxide, and 430 g of 2-ethylhexyl thioglycolate were added. Thereafter, suspension polymerization was performed while maintaining at about 75° C., and after observing the exothermic peak, the temperature was raised to 92° C. at a rate of 1° C. / min. Then, aging was performed for 60 minutes to substantially terminate the polymerization reaction.

[0287] Next, the mixture was cooled to 50° C., and 20% by mass sulfuric acid was added to dissolve the suspending agent. Then, the polymerization reaction solution was sieved with a 1.68 mm mesh to remove aggregates, and the obtained bead polymer was washed, dehydrated, and dried to obtain Resin 7.

[0288] <Resin 8, Resin 9>

[0289] As the resin 8, Tufprene 315 (manufactured by Asahi Kasei Corporation, styrene-butadiene block copolymer) was used.

[0290] As the resin 9, Miractran E394 POTA (manufactured by Tosoh Corporation, thermoplastic polyurethane elastomer) was used.

[0291] The following Table 1 shows resins 1 to 9 contained in the ablative layer (sometimes referred to as resins contained in the ablative layer).

[0292] [Table 1]

[0293]

[0294] ((2) Production of films for flexographic printing plate production)

[0295] <Manufacturing of Film for Flexographic Printing Plate Manufacturing of Example 1>

[0296] 6.5 parts by mass of the resin 1, 54.0 parts by mass of toluene, and 36.0 parts by mass of cyclohexanone were mixed to dissolve the resin 1 in the solvent.

[0297] Then, 3.5 parts by mass of carbon black (manufactured by Mitsubishi Chemical Corporation, #1000) was further added, and the mixture was mixed for 4 hours using a bead mill to obtain a carbon black dispersion.

[0298] The carbon black dispersion obtained as described above was applied onto the substrate 1 shown in Table 2 below so that the film thickness after drying was 2.5 μm, and dried at 90° C. for 2 minutes to obtain a film for flexographic printing plate production which was a laminate of an ablation layer and a substrate.

[0299] <Manufacturing of Film for Flexographic Printing Plate Manufacturing in Comparative Example 2>

[0300] Resin 8: 7.8 parts by mass of Tufprene 315 (styrene-butadiene block copolymer manufactured by Asahi Kasei Corporation), 70.4 parts by mass of toluene, and 17.6 parts by mass of propylene glycol 1-monomethyl ether 2-acetate (PMA) were mixed to dissolve Tufprene 315 in the solvent. Then, carbon black (MCF-88 manufactured by Mitsubishi Chemical Corporation) was further added and mixed for 4 hours using a ball mill to obtain a carbon black dispersion.

[0301] A film for flexographic printing plate production was obtained in the same manner as the film for flexographic printing plate production in Example 1 except that the carbon black dispersion obtained as described above was used, using the substrate 1 shown in the following Table 2.

[0302] <Manufacturing of Film for Flexographic Printing Plate Manufacturing of Comparative Example 3>

[0303] Resin 9: 7.8 parts by mass of Miractran E394 POTA (manufactured by Tosoh Corporation, thermoplastic polyurethane elastomer), 44.0 parts by mass of toluene and 44.0 parts by mass of 2-propanol were mixed to dissolve the polyamide in the solvent. Then, carbon black (manufactured by Mitsubishi Chemical Corporation, MCF-88) was further added and mixed in a ball mill for 4 hours to obtain a carbon black dispersion.

[0304] A film for flexographic printing plate production was obtained in the same manner as the film for flexographic printing plate production in Example 1 except that the carbon black dispersion obtained as described above was used, using the substrate 1 shown in the following Table 2.

[0305] <Manufacturing of Films for Flexographic Printing Plate Manufacturing of Examples 2 to 14, Comparative Example 1, and Comparative Examples 4 to 6>

[0306] The resin and substrate used were changed in combination from Table 1 and Table 2. Other conditions were the same as those of the film for producing a flexographic printing plate in Example 1, and various films for producing a flexographic printing plate were obtained.

[0307] In the following Table 2, PP represents polypropylene, and PET represents polyethylene terephthalate.

[0308] [Table 2]

[0309]

[0310] ((3) Production of Photosensitive Resin Composition)

[0311] <(Manufacturing Example) Manufacture of Unsaturated Prepolymer Composition>

[0312] The unsaturated prepolymer composition used for the photosensitive resin composition was produced as follows.

[0313] As diols, 1200 g of poly(3-methyl-1,5-pentanediol adipate) diol ("Kurapol P3010" manufactured by Kuraray Co., Ltd.), 800 g of polyoxyethylene (EO)-oxypropylene (PO) block copolymer diol ("SANNIX PL2100" manufactured by Sanyo Chemical Industries, Ltd.), and 0.03 g of dibutyltin dilaurate were added, and the mixture was stirred at 40° C. until uniform to obtain a mixture.

[0314] To the obtained mixture, 137 g of tolylene diisocyanate ("CORONATE T80" manufactured by Tosoh Corporation) was added, and the mixture was stirred until uniform to obtain a mixture.

[0315] After being homogenized, the mixture was heated to 80° C. and reacted for 4 to 5 hours to prepare a prepolymer precursor having isocyanate groups at both ends.

[0316] To the obtained prepolymer precursor, 387 g of poly(oxypropylene) glycol monomethacrylate ("Blemmer PP" manufactured by NOF Corporation) was added as a (meth)acrylation agent, and the mixture was reacted for 2 hours to obtain a reaction product.

[0317] A portion of the obtained reaction product was taken out and subjected to IR spectroscopy measurement, whereby disappearance of the isocyanate group was confirmed.

[0318] The unsaturated prepolymer composition is obtained as described above.

[0319] The unsaturated prepolymer composition was subjected to GPC measurement. The number average molecular weight of the high molecular weight body derived from the unsaturated prepolymer component in the unsaturated prepolymer composition was 22,500.

[0320] <Preparation of Photosensitive Resin Composition a>

[0321] To 68.2 parts by mass of the unsaturated prepolymer composition obtained in the above production example, 21.8 parts by mass of diethylene glycol (2-ethylhexyl) ether acrylate ("Aronix M-120" manufactured by Toagosei Co., Ltd.), 1.1 parts by mass of trimethylolpropane trimethacrylate ("NK Ester TMPT" manufactured by Shin-Nakamura Chemical Co., Ltd.), 6.3 parts by mass of dibutyl sebacate ("DBS" manufactured by Toyokuni Oil Manufacturing Co., Ltd.), 1.0 parts by mass of 2,2-dimethoxy-2-phenylacetophenone ("IRGACURE 651" manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator, and 1.6 parts by mass of 2,6-di-tert-butyl-p-cresol ("IONOL" manufactured by Oxalis Chemicals Co., Ltd.) as an antioxidant were added, and the mixture was stirred and mixed under heating at 60° C. to obtain a photosensitive resin composition a.

[0322] <Preparation of Photosensitive Resin Composition b>

[0323] Photosensitive resin composition b was obtained in the same manner as photosensitive resin composition a except that liquid polybutadiene ("LBR-305" manufactured by Kuraray) was used instead of the unsaturated prepolymer composition of the above production example.

[0324] The obtained photosensitive resin composition and film for producing a flexographic printing plate are used to sequentially undergo a laser drawing step, a forming and exposure step, a development step, a post-exposure step, and a drying step as shown in the following (4) to (8), thereby producing a flexographic printing plate.

[0325] ((4) Laser drawing of thin films for manufacturing flexographic printing plates)

[0326] The film for manufacturing a flexographic printing plate was placed in Esko CDI SPARK2530, and laser drawing was performed on the ablation layer at a resolution of 8000 dpi and a laser intensity of 3.0 J using a test image having an image pattern described later.

[0327] ((5) Forming and exposure process)

[0328] Using "ALF-213E Platesetter" manufactured by Asahi Kasei Corporation, molding and exposure were performed by (A1) to (A3).

[0329] (A1):

[0330] After the film for manufacturing a flexographic printing plate after image drawing is placed on a lower glass plate that is transparent to ultraviolet light in such a way that the ablation layer after image drawing is sandwiched between the substrate and located on the side opposite to the lower glass plate, the film for manufacturing a flexographic printing plate is fixed by vacuuming the grooves provided around the lower glass with a pump. A photosensitive resin composition is flowed on it, and a base film that becomes a support is bonded to the base film through a spacer in such a way that the photosensitive resin composition has a certain plate thickness, and a glass plate (upper glass plate) that is transparent to ultraviolet light is further pressed therefrom to form a photosensitive resin composition layer. Before relief exposure, a dedicated masking film is sandwiched between the upper glass plate and the base film to form a photosensitive resin composition layer.

[0331] (A2):

[0332] After the photosensitive resin composition layer is formed, active light (light having a wavelength distribution of 300 nm or more) is irradiated from the upper glass plate side through the base film using an ultraviolet fluorescent lamp or the like as an active light source.

[0333] Since a masking film was provided in the step of forming the photosensitive resin composition layer, masking exposure was performed by the same exposure to form the shelf layer.

[0334] (A3):

[0335] After the mask exposure step, the photosensitive resin composition layer is irradiated with the same active light rays as above from the lower glass side through the image-drawn flexographic printing plate manufacturing film to perform a relief exposure step for image formation, thereby obtaining a flexographic printing original plate.

[0336] As described above, a photosensitive resin composition layer is formed in (A1).

[0337] Here, the test image and the masking film used an image designed to form a linear unexposed portion (hereinafter referred to as "hollow" or "hollow line") with a width of 500 μm in a 300 mm×500 mm shelf layer and a 200 mm×250 mm solid image.

[0338] Next, in the above (A2) and (A3), the photosensitive resin composition layer was exposed to obtain a flexographic printing plate with a plate thickness of 3 mm and a relief depth of 2 mm. Here, the relief depth is a length obtained by subtracting the height of the shelf layer from the plate thickness, i.e., a customary term for expressing the depth of the relief of the printed image.

[0339] To adjust the relief depth, the masking exposure was adjusted appropriately.

[0340] When the relief exposure is set to 600mJ / cm 2 The relief is formed under the conditions of.

[0341] ((6) Development process)

[0342] The film for manufacturing a flexographic printing plate after the image drawing was peeled off from the flexographic printing plate, and the unexposed photosensitive resin composition was recovered and removed from the flexographic printing plate using a rubber scraper. Then, using an "AL-400W type developer" manufactured by Asahi Kasei Corporation (drum rotary spray type, drum speed: 20 rpm, spray pressure: 0.15 Pa), an aqueous solution containing 2% by mass of "APR (registered trademark) cleaning agent Type W-10" (main agent: anionic surfactant) manufactured by Asahi Kasei Corporation that can emulsify the photosensitive resin composition, 0.5% by mass of "APR (registered trademark) surface treatment agent Type A-10" (main agent: nonionic surfactant, benzophenone) manufactured by Asahi Kasei Corporation, and 0.3% by mass of "defoaming agent SH-4" (organic silicone mixture) manufactured by Asahi Kasei Corporation was used as a developer, and development was performed under the conditions of a liquid temperature of 40° C. and a development time of 10 minutes.

[0343] After development, wash with tap water until the foam generated by the developer disappears.

[0344] ((7) Post-exposure process)

[0345] Post-exposure was performed by an underwater exposure method using an "AL-200UP post-exposure machine" manufactured by Asahi Kasei Corporation equipped with both an ultraviolet fluorescent lamp and a germicidal lamp.

[0346] The exposure amount from each light source is 2000mJ / cm on the surface of the photosensitive resin composition. 2 , Germicidal lamp: 2000mJ / cm 2 Exposure time is used for exposure.

[0347] ((8) Drying process)

[0348] The post-exposed plate was dried for about 30 minutes using "ALF-DRYER" manufactured by Asahi Kasei Corporation until moisture on the surface disappeared, thereby obtaining a flexographic printing plate.

[0349] [Evaluation of Flexographic Printing Plates]

[0350] <Evaluation of Ablation Layer Dissolution Properties>

[0351] The unexposed photosensitive resin composition recovered in the development step was evaluated for dissolution of the ablation layer as follows.

[0352] 1 L of the unexposed photosensitive resin composition was filtered through a metal mesh having various mesh openings, and the mesh openings through which the ablation layer dissolved in the photosensitive resin composition passed without being removed were evaluated.

[0353] The smaller the mesh size, the smaller the mass and particle size of the dissolved ablation layer, and the lower the solubility.

[0354] In the following evaluation criteria, if it is A to D, it is evaluated that it can be used without any problem in practical use.

[0355] (Evaluation Criteria)

[0356] A: No dissolution

[0357] B: Through a metal mesh with a mesh size of less than 0.077 mm (200 mesh)

[0358] C: Through a metal mesh with a mesh size of 0.077 to less than 0.251 mm (65 mesh)

[0359] D: Through a metal mesh with a mesh size of 0.251 to less than 0.455 mm (40 mesh)

[0360] E: Through a metal mesh with a mesh size of 0.455 mm or more

[0361] <Evaluation of Hollow Depth (Residue)>

[0362] Using μDEPTH & HEIGHT MEASURING SCOPE KY-90 (manufactured by Nissho Precision Optics Co., Ltd.), the groove shape of a hollow line with a line width of 500 μm was observed and the depth of the groove was measured.

[0363] The evaluation criteria of the measurement results are shown below.

[0364] In the following evaluation criteria, if it is A to D, it is evaluated that it can be used without any problem in practical use.

[0365] (Evaluation Criteria)

[0366] A: Depth 151μm or more

[0367] B: Depth is 121 μm or more and less than 151 μm

[0368] C: Depth is 91 μm or more and less than 121 μm

[0369] D: Depth is 70 μm or more and less than 91 μm

[0370] E: Depth less than 70 μm

[0371] <Evaluation of Film Rigidity>

[0372] Evaluation of workability during vacuuming The ablation layer laminated film after image drawing was placed on a lower glass, and the air was exhausted with a roller while vacuuming the groove around the lower glass. The appearance of the film after the work was evaluated as follows.

[0373] Here, the size of the film is 500 mm×730 mm, and the portion 50 mm inside from the side is referred to as the “end portion”.

[0374] (Evaluation Criteria)

[0375] A: No wrinkles.

[0376] B: Wrinkles are produced which can be removed.

[0377] C: Removable wrinkles were produced on the entire surface.

[0378] D: Wrinkles or scratches that cannot be removed occur only at the ends.

[0379] E: Indelible wrinkles or scratches occur on the entire surface. Or air is trapped.

[0380] Various evaluation results are shown in Tables 3 and 4.

[0381] [Table 3]

[0382]

[0383] [Table 4]

[0384]

[0385] <Evaluation of Flexographic Printing Plate Obtained Using Recovered Photosensitive Resin Composition and Photosensitive Resin Composition of Unexposed Part>

[0386] A flexographic printing plate was produced by the same process under the conditions described in Example 1, using the unexposed photosensitive resin composition recovered in the above process again.

[0387] The above evaluation was performed using the produced flexographic printing plate and the recovered unexposed photosensitive resin composition to evaluate the influence of the ablation layer dissolved in the recovered unexposed photosensitive resin composition on the flexographic printing plate and the recovered photosensitive resin composition obtained when they are reused.

[0388] Table 5 shows the evaluation results.

[0389] In Example 1' in Table 5, in the process of manufacturing a flexographic printing plate of Example 1, the photosensitive resin composition of the unexposed portion recovered was reused as the photosensitive resin composition in the process of manufacturing a flexographic printing plate of Example 1, and this cycle was performed five times.

[0390] Comparative Example 1 is an example in which, in the manufacturing process of the flexographic printing plate of Example 1, a film for manufacturing a flexographic printing plate having an ablation layer containing resin 7 instead of resin 1 is used.

[0391] Furthermore, Comparative Example 1' is an example in which, in the manufacturing process of the flexographic printing plate of Example 1, a film for manufacturing a flexographic printing plate having an ablation layer containing resin 7 instead of resin 1 is used, and the recovered unexposed photosensitive resin composition is reused as the photosensitive resin composition in the manufacturing process of the flexographic printing plate, which is one cycle, and this cycle is performed 5 times.

[0392] [Table 5]

[0393]

[0394] As shown in Table 5, Example 1' was found to be superior to Comparative Example 1' in the evaluation of the dissolution property of the ablation layer and the evaluation of the produced flexographic printing plate was also superior.

[0395] This application is based on a Japanese Patent Application (Japanese Patent Application No. 2022-108488) filed with the Japan Patent Office on July 5, 2022, the contents of which are incorporated herein by reference.

[0396] Industrial Applicability

[0397] The film for producing a flexographic printing plate and the method for producing a flexographic printing plate of the present invention have industrial applicability in a wide range of general commercial printing fields.

[0398] Description of Reference Numerals

[0399] 1. Substrate

[0400] 2 Ablation layer

[0401] 2' depicts the patterned ablation layer

[0402] 3 substrate

[0403] 4 Photosensitive resin composition layer

[0404] 4' Photosensitive resin composition layer exposed by pattern

Claims

1. A film for manufacturing a flexible printing plate, comprising a substrate and an ablation layer laminated on the substrate, The ablation layer contains a resin having a structural unit (1) represented by the following general formula (1), The thickness of the substrate is greater than 10 μm and less than 100 μm, in, In formula (1), R1 and R2 each independently represent a nonpolar group, and R3 and R4 each independently represent a hydrogen atom or a nonpolar group.

2. The film for producing a flexographic printing plate according to claim 1, wherein In the formula (1), R1 and R2 are each independently any one selected from the group consisting of an alkyl group, an alkenyl group, and an alkynyl group. R3 and R4 are each independently any one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an alkynyl group.

3. The film for manufacturing a flexographic printing plate according to claim 1, wherein In the formula (1), R1 and R2 are each independently an alkyl group, R3 and R4 are each independently a hydrogen atom or an alkyl group.

4. The film for manufacturing a flexographic printing plate according to claim 1, wherein The resin further comprises a structural unit (2) derived from a monovinyl-substituted aromatic hydrocarbon.

5. The film for manufacturing a flexographic printing plate according to claim 1, wherein The substrate includes a resin having a polyester skeleton or a polyolefin skeleton.

6. The film for manufacturing a flexographic printing plate according to claim 1, wherein The substrate is formed of a resin having a polyester skeleton or a polyolefin skeleton.

7. The film for producing a flexographic printing plate according to claim 1, wherein The substrate is formed of a resin having a polyolefin skeleton.

8. A laminate comprising: Flexographic printing plate having a photosensitive resin composition layer, and The film for producing a flexographic printing plate according to any one of claims 1 to 7 on the flexographic printing original plate.

9. A method for producing a flexographic printing plate, comprising producing a flexographic printing plate using the laminate according to claim 8, The method for manufacturing the flexographic printing plate comprises: a drawing step of irradiating the film for producing a flexographic printing plate with infrared rays to draw a processing pattern; an exposure step of irradiating the photosensitive resin composition layer with ultraviolet rays using the ablation layer patterned in the drawing step as a mask to form a pattern; and The developing step is to remove the unexposed portion of the photosensitive resin composition layer.

10. The method for producing a flexographic printing plate according to claim 9, wherein: The photosensitive resin composition includes a polymer having a carbonyl group.

11. The method for producing a flexographic printing plate according to claim 9, wherein: The substrate of the film for producing a flexographic printing plate is formed of a resin having a polyester skeleton or a polyolefin skeleton.

12. The method for producing a flexographic printing plate according to claim 9, wherein: The substrate of the film for producing a flexographic printing plate is formed of a resin having a polyolefin skeleton.

13. The method for producing a flexographic printing plate according to claim 9, further comprising: The recovery step is to recover the unexposed portion removed in the development step and use it in the production of a new flexographic printing plate.

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