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

Abstract

A film for manufacturing a flexographic printing plate, the film comprising: a substrate; and an ablation layer laminated on the substrate, wherein the surface of the substrate in contact with the ablation layer contains a resin having a polyolefin skeleton, and the ablation layer contains a modified polyolefin and a polyurethane composed of a polyol and a polyisocyanate.

Description

Film for producing flexographic printing plates and method for producing flexographic printing plates

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

[0002] In recent years, flexographic printing using flexographic printing plates has been widely used as a method for printing on flexible packaging materials such as paper, film, etc. Methods for producing flexographic printing plates include, for example, the following methods.

[0003] First, a flexographic printing plate precursor having a photosensitive resin composition layer on a support is exposed to ultraviolet light (back exposure) from the support side to form a uniform photocured layer. Next, relief exposure is performed from the backside, i.e., the uncured photosensitive resin composition layer side opposite the UV-exposed side. Examples of relief exposure methods include a method of UV exposure through a transparent image carrier (mask) such as a negative film that selectively transmits UV light, and a method of UV exposure through a thin layer in which a digital image has been ablated with an infrared laser to form UV-transmitting areas. The photosensitive resin composition in the unexposed areas of the flexographic printing plate precursor is then developed by, for example, washing away, to form a relief image, thereby obtaining a flexographic printing plate.

[0004] In the development of photosensitive resin compositions, due to the recent increase in environmental awareness, water development methods that do not use organic solvents and thermal development methods that do not use developers have been considered. However, both of these methods are premised on the removal of unexposed portions of the photosensitive resin composition in the development step and then discarding the resulting product, and there is a problem in that there is still room for improvement in terms of reducing the burden on the environment.

[0005] As an improvement method from the viewpoint of reducing the burden on the environment, a method for producing a flexographic printing plate using a liquid photosensitive resin composition has been proposed, in which the photosensitive resin composition in the unexposed areas is recovered and reused in the production of a flexographic printing plate (see, for example, Patent Document 1). The method for producing a flexographic printing plate described in Patent Document 1 can reduce the amount of photosensitive resin composition in the unexposed areas that is discarded and reduce the production costs of flexographic printing plates, and is therefore widely used as a method for producing flexographic printing plates that is highly environmentally adaptable. On the other hand, in such a method for producing a flexographic printing plate, it is important to recover the photosensitive resin composition in the unexposed areas in a condition comparable to that when it was unused.

[0006] Recently, computer-to-plate (CTP) technology has become known as a method for producing flexographic printing plates. In this CTP technology, an ablation layer that can be ablated by infrared light is provided on a photosensitive resin composition layer, and the ablation layer is removed in a desired shape by irradiating it with an infrared laser, forming a transparent area for actinic light corresponding to a negative. Next, ultraviolet light is irradiated onto the photosensitive resin composition layer using the ablation layer as a mask, causing the photosensitive resin composition to react in the same shape as the transparent area formed in the ablation layer, thereby performing relief exposure. Finally, the unnecessary ablation layer and the unexposed areas of the photosensitive resin composition are developed and removed to produce a flexographic printing plate.

[0007] Patent No. 5996197

[0008] As described above, various methods for producing flexographic printing plates have been reported, but there is still room for improvement. An object of the present invention is to provide a film for producing flexographic printing plates, which includes an ablation layer that is excellent in strength and storage stability, and is capable of forming fine images even on photosensitive resin that has been stored for a long period of time.

[0009] The present inventors have found that the above object can be achieved by selecting a predetermined substrate and adjusting the composition of the resin that constitutes the ablation layer.

[0010] The present invention includes the following embodiments. [1] A film for producing a flexographic printing plate, comprising: a substrate; and an ablation layer laminated on the substrate, wherein the surface of the substrate in contact with the ablation layer comprises a resin having a polyolefin skeleton, and the ablation layer comprises: a polyurethane composed of a polyol and a polyisocyanate; and a modified polyolefin. [1-1] The film for producing a flexographic printing plate according to [1], wherein the modified polyolefin comprises an acid-modified polyolefin. [1-2] The film for producing a flexographic printing plate according to [1] or [1-1], wherein the modified polyolefin comprises a halogenated polyolefin. [1-3] The film for producing a flexographic printing plate according to any of [1] to [1-2], wherein the modified polyolefin comprises an acid-modified halogenated polyolefin. [2] The film for producing a flexographic printing plate according to any of [1] to [1-3], wherein the surface of the substrate in contact with the ablation layer has a water contact angle of 80° or more. [2-1] The film for producing a flexographic printing plate according to any one of [1] to [2], wherein the water contact angle on the surface of the substrate in contact with the ablation layer is from 80° to 150°. [2-2] The film for producing a flexographic printing plate according to any one of [1] to [2-1], wherein the water contact angle on the surface of the substrate in contact with the ablation layer is from 90° to 140°. [2-3] The film for producing a flexographic printing plate according to any one of [1] to [2-2], wherein the water contact angle on the surface of the substrate in contact with the ablation layer is from 100° to 130°. [3] The film for producing a flexographic printing plate according to any one of [1] to [2-3], wherein the weight ratio of the polyurethane to the modified polyolefin is from 2.0 to 50.0. [3-1] The film for producing a flexographic printing plate according to any one of [1] to [3], wherein the weight ratio of the polyurethane to the modified polyolefin is from 3.0 to 30.0. [3-2] The film for producing a flexographic printing plate according to any one of [1] to [3-1], wherein the weight ratio of the polyurethane to the modified polyolefin is 4.0 to 15.0.[3-3] The film for producing a flexographic printing plate according to any one of [1] to [3-2], wherein the weight ratio of the polyurethane to the modified polyolefin is 8.0 to 15.0. [4] The film for producing a flexographic printing plate according to any one of [1] to [3-3], wherein the ratio (NCO / OH) of the number of moles of isocyanate groups in the polyisocyanate to the number of moles of hydroxy groups in the polyol is 4.0 or more. [4-1] The film for producing a flexographic printing plate according to any one of [1] to [4], wherein the ratio (NCO / OH) of the number of moles of isocyanate groups in the polyisocyanate to the number of moles of hydroxy groups in the polyol is 4.0 to 60.0. [5] The film for producing a flexographic printing plate according to any one of [1] to [4], wherein the ratio (NCO / OH) of the number of moles of isocyanate groups in the polyisocyanate to the number of moles of hydroxy groups in the polyol is 8.0 or more. [5-1] The film for producing a flexographic printing plate according to any one of [1] to [5], wherein the ratio (NCO / OH) of the number of moles of isocyanate groups in the polyisocyanate to the number of moles of hydroxy groups in the polyol is 8.0 to 50.0. [5-2] The film for producing a flexographic printing plate according to any one of [1] to [5-1], wherein the ratio (NCO / OH) of the number of moles of isocyanate groups in the polyisocyanate to the number of moles of hydroxy groups in the polyol is 16.0 to 40.0. [6] The film for producing a flexographic printing plate according to any one of [1] to [5-2], wherein the number of isocyanate groups contained in the polyisocyanate is 3 or more per molecule. [6-1] The film for producing a flexographic printing plate according to any one of [1] to [6], wherein the number of isocyanate groups contained in the polyisocyanate is 3 to 5 per molecule. [7] The film for producing a flexographic printing plate according to any one of [1] to [6-1], wherein the polyol comprises a polyester polyol, the polyester polyol comprises a structural unit derived from a diol, a structural unit derived from an aromatic dicarboxylic acid, and a structural unit derived from an aliphatic dicarboxylic acid, and the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid is 1.0 to 50.0.[7-1] The film for producing a flexographic printing plate according to any one of [1] to [7], wherein the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid is 1.0 to 10.0. [7-2] The film for producing a flexographic printing plate according to any one of [1] to [7-1], wherein the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid is 2.0 to 8.0. [7-3] The film for producing a flexographic printing plate according to any one of [1] to [7-2], wherein the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid is 3.0 to 6.0. [8] A method for producing a flexographic printing plate, comprising: a drawing step of irradiating an ablation layer of the film for producing a flexographic printing plate according to any one of [1] to [7-3] with infrared light to draw and process a pattern; and an exposure step of irradiating a photosensitive resin composition layer of a flexographic printing plate precursor with ultraviolet light, using the ablation layer on which the pattern has been drawn and processed in the drawing step as a mask, to form a pattern. [9] The manufacturing method according to [8], wherein the ablation layer and the photosensitive resin composition layer are in direct contact with each other in the exposure step.

[10] The manufacturing method according to [8] or [9], wherein the photosensitive resin composition layer is in a liquid state at a temperature of 10 to 60°C.

[0011] The present invention can provide a film for producing flexographic printing plates, which includes an ablation layer that is excellent in strength and storage stability, and is capable of forming fine images even on photosensitive resin that has been stored for a long period of time.

[0012] 1 shows a schematic cross-sectional view of a film for producing a flexographic printing plate of the present invention. 2 shows a schematic view of a method for producing a flexographic printing plate using the film for producing a flexographic printing plate of the present invention.

[0013] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to these and various modifications are possible without departing from the gist of the present invention.

[0014] [Film for producing flexographic printing plates] One embodiment of the present invention relates to a film for producing flexographic printing plates, comprising a substrate and an ablation layer laminated on the substrate, wherein the surface of the substrate in contact with the ablation layer comprises a resin having a polyolefin skeleton, and the ablation layer comprises: a polyurethane composed of a polyol and a polyisocyanate; and a modified polyolefin.

[0015] The film for producing a flexographic printing plate according to this embodiment includes an ablation layer that is excellent in strength and storage stability, and is capable of forming a fine image even on a photosensitive resin that has been stored for a long period of time.

[0016] 1 shows a schematic cross-sectional view of a film for producing a flexographic printing plate according to this embodiment. The film for producing a flexographic printing plate according to this embodiment is formed by laminating a substrate 1 and an ablation layer 2 that functions as a mask when forming the desired relief pattern of the flexographic printing plate. The film for producing a flexographic printing plate according to this embodiment will be described in detail below.

[0017] (Substrate) The film for producing a flexographic printing plate of this embodiment has a substrate 1 and an ablation layer 2 laminated on the substrate 1, and since the ablation layer 2 has an image drawn on it, it plays the role of a negative film for forming a relief in the manufacturing process of a flexographic printing plate described below.

[0018] The quality of the relief, particularly image reproducibility, is significantly affected by the negative film through which ultraviolet light passes during relief exposure. Generally, the thicker the negative film, the greater the bending and scattering of ultraviolet light within the negative film, and the lower the image reproducibility. Since the thickness of the substrate 1 shown in Figure 1 accounts for the majority of the overall thickness of the negative film, a smaller thickness of the substrate 1 is preferable from the perspective of the quality of the flexographic printing plate.

[0019] On the other hand, it is also important that the negative film has a certain degree of rigidity and dimensional stability. If the negative film easily deforms, it can cause deformation or damage to the image formed on the negative film in processes prior to relief exposure, resulting in a tendency for image reproducibility to decline. However, if the negative film is too rigid, it can be incompatible with the equipment used in the manufacturing process of the intended flexographic printing plate, or excessive stress concentration on the ablation layer during handling can tend to cause irreversible damage such as scratches or wrinkles.

[0020] From the above viewpoints, the thickness of the substrate 1 is preferably 10 μm or more and less than 100 μm. This numerical range allows for the production of a film for flexographic printing plates with excellent image reproducibility and appropriate rigidity. Furthermore, 20 μm or more is more preferable, and 40 μm or more is even more preferable. By making the thickness of the substrate 1 10 μm or more, sufficient strength and rigidity for practical use can be obtained, and deformation and damage to the image can be suppressed during the flexographic printing plate production process. Furthermore, from the viewpoints of ensuring appropriate flexibility and good handleability during the flexographic printing plate production process, the thickness of the substrate 1 is preferably less than 100 μm, more preferably 90 μm or less, and even more preferably 70 μm or less.

[0021] The surface of the substrate that contacts the ablation layer (preferably the entire substrate) contains a resin having a polyolefin skeleton.

[0022] Resins having a polyolefin skeleton include, but are not limited to, polyethylene, polypropylene, and copolymerized resins thereof.

[0023] Resins having a polyolefin skeleton have high oxygen permeability. Here, oxygen permeability is one of the physical properties of a film, and is the oxygen permeability of 1 m of film under the condition of 1 atm (1 atmosphere). ２ It represents the amount of oxygen passing through the body per day. The unit is cm ３ / m ２ - 24h atm. The higher the value, the easier it is to pass, and the lower the value, the harder it is to pass.

[0024] In the manufacturing process of flexographic printing plates, when a photosensitive resin composition layer is cured by ultraviolet irradiation, the curing proceeds through radical polymerization. If oxygen is present during this radical polymerization, the radical-generating compound reacts with the oxygen, inhibiting the polymerization reaction. Long-term storage of a photosensitive resin increases the amount of dissolved oxygen, which tends to increase the difference in oxygen concentration between the surface and the interior of the photosensitive resin during the exposure process described below. As a result, the uniformity of the curing properties of the photosensitive resin is impaired, making it difficult to produce particularly fine images. By using a resin having a polyolefin skeleton with high oxygen permeability, the oxygen concentration gradient between the surface and the interior of the photosensitive resin is reduced (more specifically, the oxygen concentration throughout the photosensitive resin composition layer during exposure is uniformed), making it possible to produce fine images even with a photosensitive resin that has increased dissolved oxygen due to long-term storage. The substrate of this embodiment may be a laminate of multiple different films.

[0025] In the film for producing a flexographic printing plate of this embodiment, the water contact angle of the surface of the substrate is preferably from 80° to 150°, more preferably from 90° to 140°, and even more preferably from 100° to 130°. The water contact angle can be measured by the method described in the Examples below.

[0026] When the water contact angle is within the above range, the adhesion between the substrate and the ablation layer is improved, and the strength and storage stability of the ablation layer tend to be improved.

[0027] In the film for producing flexographic printing plates of this embodiment, the substrate may be used in an untreated state, or may be subjected to a predetermined surface treatment as necessary, or may be provided with a function such as antistatic treatment. Examples of surface treatments include corona treatment and matte finish.

[0028] (Ablation Layer) In the film for producing a flexographic printing plate of this embodiment, as shown in Fig. 1, an ablation layer 2 is laminated on a substrate 1. The ablation layer is preferably laminated directly on the substrate.

[0029] The ablation layer 2 contains a predetermined resin, can be ablated by an infrared laser, and also functions as a light blocking layer for rays other than infrared rays.

[0030] The ablation layer preferably includes a resin, an infrared absorbing material, and a shielding material.

[0031] <Resin> The resin of the ablation layer contains polyurethane composed of polyol and polyisocyanate. The polyurethane is obtained by reacting the polyol with the polyisocyanate.

[0032] When the ablation layer contains polyurethane, the strength of the ablation layer tends to be improved, and the dispersibility of the infrared absorbing material and the infrared shielding material (particularly carbon black) tends to be improved.

[0033] The ratio (NCO / OH) of the number of moles of isocyanate groups in the polyisocyanate to the number of moles of hydroxy groups in the polyol is preferably 4.0 to 60.0, more preferably 8.0 to 50.0, and even more preferably 16.0 to 40.0. The number of moles of hydroxy groups and the number of moles of isocyanate groups are based on the polyol and polyisocyanate before they form the urethane (i.e., before the reaction).

[0034] When the NCO / OH ratio is within the above range, the strength of the ablation layer tends to be improved, and the dispersibility of the infrared absorbing material and the shielding material (especially carbon black) tends to be improved. The storage stability of the ablation layer also tends to be improved. Furthermore, when the NCO / OH ratio is within the above range, both the strength of the ablation layer and the laser sensitivity can be achieved. It is presumed that the compatibility of the strength and the laser sensitivity of the ablation layer is due to intermolecular interactions caused by the excess isocyanate groups or amino groups derived therefrom, but the present invention is not limited by this presumption.

[0035] The NCO / OH ratio can be adjusted as appropriate by changing the type and amount ratio of the polyol and polyisocyanate that make up the polyurethane. The NCO / OH ratio can be measured using pyrolysis GC-MS. It should be noted that excessive isocyanate groups present in the ablation layer may be hydrolyzed over time and converted to amino groups. That is, when analyzing the components of the ablation layer, the isocyanate groups contained in the polyisocyanate may be detected as amino groups. Even if detected as amino groups during analysis, it is possible to infer that they were originally isocyanate groups by combining this information with other structural information.

[0036] The amount of polyurethane is preferably 20 to 70% by weight, more preferably 30 to 60% by weight, and even more preferably 35 to 55% by weight, based on the weight of the ablation layer.

[0037] When the amount of polyurethane is within the above range, the strength of the ablation layer tends to be improved, and the dispersibility of the infrared absorbing material and the infrared shielding material (particularly carbon black) tends to be improved.

[0038] The polyol constituting the polyurethane preferably includes a polyester polyol.

[0039] When the polyol contains a polyester polyol, the strength of the ablation layer tends to be improved, and the dispersibility of the infrared absorbing material and the infrared shielding material (particularly, carbon black) tends to be improved.

[0040] The polyester polyol preferably contains a structural unit derived from a diol and a structural unit derived from a dicarboxylic acid, i.e., the polyester polyol is preferably obtained by reacting a diol with a dicarboxylic acid.

[0041] {Diol} The type of diol constituting the polyester polyol is not particularly limited, but is preferably a diol having 1 to 10 carbon atoms, more preferably a diol having 2 to 8 carbon atoms, and even more preferably a diol having 2 to 6 carbon atoms.

[0042] Examples of diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-2,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 3,5-heptanediol, 1,8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, diethylene glycol, triethylene glycol, cyclohexanedimethanol, and cyclohexanediol.

[0043] The diols may be used alone or in combination of two or more.

[0044] As the diol, it is preferable to use a combination of ethylene glycol and neopentyl glycol.

[0045] {Dicarboxylic Acid} Examples of dicarboxylic acids constituting the polyester polyol include aromatic dicarboxylic acids and aliphatic dicarboxylic acids.

[0046] Aromatic dicarboxylic acids include, for example, phthalic acid, terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid.

[0047] Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, 2-methylsuccinic acid, 2-methyladipic acid, 3-methyladipic acid, 3-methylpentanedioic acid, 2-methyloctanedioic acid, 3,8-dimethyldecanedioic acid, 3,7-dimethyldecanedioic acid, hydrogenated dimer acid, dimer acid, 1,2-cyclopentanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-dicarboxylmethylenecyclohexane, nadic acid, and methylnadic acid.

[0048] The dicarboxylic acids may be used alone or in combination of two or more.

[0049] As the dicarboxylic acid, it is preferable to use a combination of an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and it is more preferable to use a combination of terephthalic acid, isophthalic acid and azelaic acid.

[0050] The molar ratio of aromatic dicarboxylic acid to aliphatic dicarboxylic acid (aromatic dicarboxylic acid / aliphatic dicarboxylic acid) is preferably 1.0 to 10.0, more preferably 2.0 to 8.0, and even more preferably 3.0 to 6.0.

[0051] When the molar ratio of aromatic dicarboxylic acid to aliphatic dicarboxylic acid is within the above range, the strength of the ablation layer tends to be improved, the dispersibility of the infrared absorbing material and the infrared shielding material (particularly carbon black) tends to be improved, and the storage stability of the ablation layer also tends to be improved.

[0052] {Polyisocyanate} The number of isocyanate groups contained in the polyisocyanate constituting the polyurethane is preferably 2 to 6, and more preferably 3 to 5, per molecule.

[0053] When the number of isocyanate groups is within the above range, the strength of the ablation layer tends to be improved, the dispersibility of the infrared absorbing material and the infrared shielding material (especially carbon black) tends to be improved, and the storage stability of the ablation layer also tends to be improved.

[0054] Examples of polyisocyanates include aliphatic diisocyanates, aromatic diisocyanates, and aliphatic triisocyanates.

[0055] Examples of aliphatic diisocyanates include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, norbornane diisocyanate, 1,4-isocyanatocyclohexane, 1,3-bis(isocyanatomethyl)-cyclohexane, and 1,3-bis(2-isocyanatopropyl-2-yl)-cyclohexane.

[0056] Examples of aromatic diisocyanates include tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylene diisocyanate, and 1,5-naphthalene diisocyanate.

[0057] Aliphatic triisocyanates include, for example, 1,6,11-undecane triisocyanate, 1,8-diisocyanato-4-isocyanatomethyloctane, and 1,3,6-triisocyanatomethylhexane.

[0058] Examples of further polyisocyanates include polymethylene polyphenyl polyisocyanates and polyisocyanates derived from the diisocyanate compounds, such as isocyanurate polyisocyanates, biuret polyisocyanates, urethane polyisocyanates, allophanate polyisocyanates, and carbodiimide polyisocyanates.

[0059] The polyisocyanate is preferably an adduct (adduct-type polyisocyanate). Specifically, the adduct is preferably an addition product of a polyisocyanate and a polyhydric alcohol.

[0060] The polyisocyanate constituting the adduct is preferably a diisocyanate. Specific examples of the diisocyanate are as described above.

[0061] The polyhydric alcohol constituting the adduct is preferably a trihydric alcohol, such as trimethylolethane, trimethylolpropane, hexanetriol, and glycerin.

[0062] {Modified Polyolefin} The resin of the ablation layer further contains a modified polyolefin, which tends to improve adhesion to the substrate and improve the strength and storage stability of the ablation layer.

[0063] Examples of modified polyolefins include acid-modified polyolefins, halogenated polyolefins, and acid-modified halogenated polyolefins.

[0064] Examples of acid-modified polyolefins include polyolefins modified with maleic anhydride or (meth)acrylic acid, and examples of acid-modified polyolefins include maleic anhydride-acrylic-modified polyethylene, maleic anhydride-acrylic-modified polypropylene, maleic anhydride-modified polyethylene, and maleic anhydride-modified polypropylene.

[0065] The number average molecular weight of the acid-modified polyolefin is preferably 10,000 to 100,000, particularly preferably 20,000 to 50,000, from the viewpoint of achieving both compatibility with the raw materials constituting the ablation layer and adhesion to the substrate.

[0066] The halogenated polyolefin is preferably a chlorinated polyolefin, such as chlorinated polypropylene, chlorinated polyethylene, and chlorinated ethylene vinyl acetate copolymer.

[0067] The halogen content of the halogenated polyolefin is preferably 20% or more, particularly preferably 30% or more, from the viewpoint of ensuring compatibility with the raw materials constituting the ablation material. The number average molecular weight of the halogenated polyolefin is preferably 5,000 to 30,000, particularly preferably 8,000 to 20,000, from the viewpoint of achieving both compatibility with the raw materials constituting the ablation material and adhesion to the substrate.

[0068] Examples of the acid-modified halogenated polyolefin include maleic anhydride-modified chlorinated polyethylene and maleic anhydride-modified chlorinated polypropylene.

[0069] The halogen content of the acid-modified halogenated polyolefin is preferably 15% or more, particularly preferably 20% or more, from the viewpoint of ensuring compatibility with the raw materials constituting the ablation layer. The number average molecular weight of the acid-modified halogenated polyolefin is preferably 10,000 to 50,000, particularly preferably 15,000 to 30,000, from the viewpoint of achieving both compatibility with the raw materials constituting the ablation layer and adhesion to the substrate.

[0070] The weight ratio of polyurethane to modified polyolefin (polyurethane / modified polyolefin) is preferably 2.0 to 50.0, more preferably 3.0 to 30.0, even more preferably 4.0 to 15.0, and particularly preferably 8.0 to 15.0.

[0071] When the weight ratio of polyurethane to modified polyolefin is within the above range, the adhesion to the substrate is improved, and the strength and storage stability of the ablation layer tend to be improved.

[0072] The weight proportion of the modified polyolefin in the ablation layer is preferably 2 to 50% by weight, more preferably 2 to 33% by weight, even more preferably 3 to 25% by weight, particularly preferably 6 to 20% by weight, and even more particularly preferably 6 to 11% by weight, from the viewpoint of achieving both the strength of the ablation layer and adhesion to the substrate.

[0073] <Infrared absorbing material> The ablation layer 2 preferably contains an infrared absorbing material for ablation processing. Examples of the infrared absorbing material include elements or compounds that have strong absorption in the range of 750 to 2000 nm.

[0074] Examples of infrared-absorbing substances include, but are not limited to, inorganic pigments such as carbon black, graphite, copper chromite, and chromium oxide; and dyes such as polyphthalocyanine compounds, cyanine dyes, and metal thiolate dyes. The smaller the particle size, the higher the sensitivity to infrared lasers. Carbon black, in particular, can be used over a wide particle size range of 13 to 85 nm, making it a preferred infrared-absorbing substance. Carbon black can also function as a shielding substance, as described below. These infrared-absorbing substances are added in a range that provides sensitivity sufficient for ablation with the laser beam used.

[0075] <Shielding Material> The ablation layer 2 preferably contains a non-infrared shielding material for blocking ultraviolet rays and the like, since it serves as a mask. As the non-infrared shielding material, a material that reflects or absorbs ultraviolet light can be used.

[0076] Examples of the shielding material include, but are not limited to, ultraviolet absorbers, carbon black, and graphite.

[0077] <Thickness of Ablation Layer> The ablation layer 2 of the film for producing flexographic printing plates of this embodiment should be thicker in order to ensure blocking properties against ultraviolet rays during the exposure process described below, and should be thinner in order to enhance ablation properties.

[0078] From the above viewpoint, the thickness of the ablation layer 2 is preferably 0.1 μm or more and 20 μm or less, more preferably 0.5 μm or more and 15 μm or less, and even more preferably 1.0 μm or more and 10 μm or less.

[0079] For the non-infrared shielding effect of the ablation layer 2, the optical density of the ablation layer 2 is preferably 2.0 or more, and more preferably 2.5 or more.

[0080] The optical density can be measured using a D200-II transmission densitometer (manufactured by GretagMacbeth). The optical density is measured by the so-called visual sense (ISO visual), and the light to be measured has a wavelength range of about 400 to 750 nm.

[0081] [Method of Manufacturing Film for Flexographic Printing Plate Production] The method of manufacturing a film for flexographic printing plate production in this embodiment is not limited to the following, but for example, when carbon black is used as both an infrared absorbing material and a non-infrared shielding material, a solution of the above-mentioned resin is first 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. Thereafter, the solution or dispersion for forming the ablation layer is coated on a predetermined substrate 1 to produce the film.

[0082] An effective method for dispersing carbon black in the resin solution is to combine forced stirring with a stirring blade and stirring using ultrasonic waves or various mills. Alternatively, a method of pre-kneading the resin, carbon black, and dispersant using an extruder or kneader and then dissolving them in a solvent is also effective for achieving good carbon black dispersibility. Another method is to forcibly disperse carbon black in a resin in the form of a latex dispersion.

[0083] The solvent used to prepare the solution or dispersion for forming the ablation layer 2 can be appropriately selected taking into consideration the solubility of the resin and infrared absorber used. Only one solvent may be used, or two or more solvents may be mixed and used.

[0084] Furthermore, for example, by mixing a solvent with a relatively low boiling point with a solvent with a high boiling point and controlling the evaporation rate of the solvent, the film quality of the ablation layer 2 can also be improved.

[0085] Solvents for forming the ablation layer 2 include, but are not limited to, toluene, xylene, cyclohexane, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, methyl ethyl ketone, acetone, cyclohexanone, methylcyclohexane, ethylene glycol, propylene glycol, ethanol, water, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, dimethylacetamide, dimethylformamide, n-propyl alcohol, i-propyl alcohol, 1,4-dioxane, tetrahydrofuran, diethyl ether, n-hexane, n-heptane, n-pentane, acetonitrile, and analogs thereof.

[0086] [Laminate] The laminate of this embodiment has a configuration in which a flexographic printing plate precursor having a photosensitive resin composition layer and the above-mentioned film for producing a flexographic printing plate of this embodiment are laminated on the flexographic printing plate precursor. The ablation layer of the film for producing a flexographic printing plate in the laminate may be that before or after pattern drawing processing.

[0087] The flexographic printing original plate has a support and a photosensitive resin composition layer laminated on the support.

[0088] As will be described later, a relief is formed on a flexographic printing plate precursor by patternwise exposure, and the unexposed areas are removed by development to obtain the desired flexographic printing plate.

[0089] (Support) Supports for the printing plate precursor include, but are not limited to, polyester films, polyamide films, polyacrylonitrile films, polyvinyl chloride films, etc. Among these, polyester films are preferred as the support.

[0090] The polyester used for the support is not limited to the following, but examples thereof include polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0091] The thickness of the support is not particularly limited, but is preferably 50 to 300 μm.

[0092] Furthermore, in order to enhance the adhesive strength 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, but examples thereof include the adhesive layers described in WO 2004 / 104701, Japanese Patent No. 3094647, and Japanese Patent No. 2634429.

[0093] (Photosensitive Resin Composition Layer) The printing original plate has a photosensitive resin composition layer on a support. The photosensitive resin composition layer may be laminated directly on the support, or may be laminated indirectly via a predetermined adhesive layer or the like.

[0094] The photosensitive resin composition layer is preferably a photosensitive resin that is liquid under conditions of 10 to 60° C. A photosensitive resin that is liquid under these conditions has fluidity during the exposure step, and therefore, dissolved oxygen tends to move more easily within the photosensitive resin than a solid photosensitive resin. This makes it easier to homogenize the oxygen concentration throughout the photosensitive resin composition layer during exposure, making it possible to create fine images even after long-term storage.

[0095] 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. Furthermore, the photosensitive resin composition layer may further contain auxiliary additive components, as necessary.

[0096] Each component of the photosensitive resin composition layer will be described in detail below.

[0097] <Polymer (b-1)> The polymer (b-1) may be 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.

[0098] Examples of the polymer (b-1) include those conventionally used in the production of flexographic printing plates, such as fully or partially hydrolyzed polyvinyl esters, partially hydrolyzed polyvinyl acetates, polyvinyl alcohol derivatives, partially hydrolyzed vinyl acetate / alkylene oxide graft copolymers or polyvinyl alcohols subsequently acrylated by a polymer-analogous reaction, polybutadienes, polyamides, and mixtures thereof.

[0099] In addition to those mentioned above, for example, thermoplastic elastomeric block copolymers may also be used.

[0100] The thermoplastic elastomer block copolymer may include one containing at least one block containing an alkenyl aromatic monomer unit and at least one block containing a 1,3-diene monomer unit. Examples of alkenyl aromatic compounds that form the alkenyl aromatic monomer units include styrene, α-methylstyrene, and vinyltoluene. As the 1,3-dienes, butadiene and isoprene are preferred from the viewpoints of reducing the steric hindrance of the vinyl group, increasing the photocrosslinking efficiency, and preventing the elution of the ablation layer into the printing plate blank after exposure.

[0101] Examples of the polymer (b-1) include, but are not limited to, polyester, polyamide, and polyurethane. From the viewpoint of preventing damage to the relief surface due to the load when the film for producing a flexographic printing plate is peeled off after the exposure step, it is more preferable that the polymer (b-1) contains polyurethane. Furthermore, from the viewpoint of improving the mechanical properties of the flexographic printing plate finally obtained by photocrosslinking, it is preferable that the polyurethane has a (meth)acrylic group at its terminal group.

[0102] Examples of methods for producing polyurethanes having (meth)acrylic groups at their terminals include a method in which a diol having repeating units in its molecule is reacted with a diisocyanate to form a polyurethane having isocyanate groups at its terminals with a given molecular weight, and then the polyurethane is reacted with a compound containing active hydrogen and a (meth)acrylic group in one molecule.Furthermore, a method in which a diol having repeating units in its molecule is reacted with a diisocyanate to form a polyurethane having isocyanate groups at its terminals with a given molecular weight, and then the polyurethane is reacted with a compound containing a hydroxyl group and a (meth)acrylic group in one molecule is also included.

[0103] The polyurethane structure obtained by the above-mentioned production method is a structure formed by reacting a diol having a repeating unit in the molecule with a diisocyanate.

[0104] Hereinafter, the "polyurethane having a (meth)acrylic group at the terminal group" produced by the above-mentioned method will be referred to as an "unsaturated prepolymer."

[0105] The "diol having a repeating unit in the molecule" used in producing the unsaturated prepolymer is not limited to the following, but examples thereof include polyester diols composed of dicarboxylic acids and diols, polyether diols, polyether polyester copolymer diols, 1,2-polybutadiene compounds having terminal hydroxyl groups, etc. The diols having a repeating unit in the molecule may be used alone or in combination of two or more.

[0106] Examples of dicarboxylic acids constituting the polyester diol include, but are not limited to, succinic acid, glutaric acid, adipic acid, pimenic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, terephthalic acid, isophthalic acid, and 1,5-naphthalenedicarboxylic acid.

[0107] Examples of diols constituting the polyester diol include, but are not limited to, 1,4-butanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, neopentyldiol, 1,6-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, and diethylene glycol (dioxyethylenediol).

[0108] Examples of the polyether diol include, but are not limited to, polyoxyethylene diol, polyoxypropylene diol, polyoxytetramethylene diol, polyoxy 1,2-butylene diol, polyoxyethylene / polyoxypropylene random copolymer diol, polyoxyethylene / polyoxypropylene block copolymer diol, polyoxyethylene / polyoxytetramethylene random copolymer diol, and polyoxyethylene / polyoxytetramethylene block copolymer diol.

[0109] The polyether polyester copolymer diol is not limited to the following, but examples thereof include copolymers having a structure in which repeating units forming the molecular chain of the above-mentioned polyether diol and repeating units forming the molecular chain of the above-mentioned polyester diol are linked in block or random fashion.

[0110] The 1,2-polybutadiene compound having terminal hydroxyl groups may be a hydrogenated compound. Examples of the 1,2-polybutadiene compound having terminal hydroxyl groups include, but are not limited to, hydrogenated poly-1-butene and hydrogenated 1,2-polybutadiene. The number of terminal hydroxyl groups is not particularly limited, but from the viewpoint of preventing damage to the relief surface due to the load when the printing plate production film is peeled off after exposure, the number of terminal hydroxyl groups per molecule is preferably 1.2 or more, more preferably 1.5 or more, and even more preferably 2.0 or less.

[0111] Examples of the diisocyanate include, but are not limited to, tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, and norbornene diisocyanate.

[0112] The diisocyanates may be used alone or in combination of two or more.

[0113] <Ethylenically Unsaturated Compound (b-2)> 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 a radically polymerizable unsaturated double bond.

[0114] Examples of the ethylenically unsaturated compound (b-2) include, but are not limited to, olefins such as ethylene, propylene, vinyltoluene, styrene, and divinylbenzene; acetylenes; (meth)acrylic acid and / or derivatives thereof; haloolefins; unsaturated nitriles such as acrylonitrile; unsaturated amides and derivatives thereof such as acrylamide and methacrylamide; unsaturated dicarboxylic acids and derivatives thereof such as maleic anhydride, maleic acid, and fumaric acid; vinyl acetates; N-vinylpyrrolidone; N-vinylcarbazole; and N-substituted maleimide compounds.

[0115] Examples of the derivatives include, but are not limited to, alicyclic compounds having a cycloalkyl group, a bicycloalkyl group, a cycloalkenyl group, a bicycloalkenyl group, or the like; aromatic compounds having a benzyl group, a phenyl group, a phenoxy group, or a naphthalene skeleton, an anthracene skeleton, a biphenyl skeleton, a phenanthrene skeleton, a fluorene skeleton, or the like; compounds having an alkyl group, a halogenated alkyl group, an alkoxyalkyl group, a hydroxyalkyl group, an aminoalkyl group, a glycidyl group, or the like; ester compounds with polyhydric alcohols such as alkylene glycol, polyoxyalkylene glycol, polyalkylene glycol, and trimethylolpropane; and compounds having a polysiloxane structure such as polydimethylsiloxane and polydiethylsiloxane.

[0116] The ethylenically unsaturated compound (b-2) may also be a heteroaromatic compound containing elements such as nitrogen and sulfur.

[0117] Examples of the (meth)acrylic acid and / or derivatives thereof include, but are not limited to, diacrylates and dimethacrylates of alkanediols such as hexanediol and nonanediol; diacrylates and dimethacrylates of ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, polyethylene glycol, and butylene glycol; trimethylolpropane tri(meth)acrylate; dimethyloltricyclodecane di(meth)acrylate; isobornyl(meth)acrylate; phenoxypolyethylene glycol (meth)acrylate; pentaerythritol tetra(meth)acrylate, etc. These may be used alone or in combination of two or more.

[0118] From the viewpoints of improving the strength of the flexographic printing original plate and preventing damage to the relief surface due to the load when the film for producing a flexographic printing plate of this embodiment is peeled off after exposure, it is preferable to use at least one type of (meth)acrylate as the ethylenically unsaturated compound (b-2), and it is more preferable to use at least one type of bifunctional (meth)acrylate.

[0119] <Photopolymerization Initiator (b-3)> The photosensitive resin composition layer preferably contains a photopolymerization initiator (b-3).

[0120] The photopolymerization initiator (b-3) is a compound that absorbs light energy and generates radicals, and examples thereof include a degradable photopolymerization initiator, a hydrogen abstraction photopolymerization initiator, and a compound having a moiety that functions as a hydrogen abstraction photopolymerization initiator and a moiety that functions as a degradable photopolymerization initiator in the same molecule.

[0121] Examples of such photopolymerization initiator (b-3) include, but are not limited to, benzophenone, 4,4-bis(diethylamino)benzophenone, 3,3',4,4'-benzophenonetetracarboxylic anhydride, 3,3',4,4'-tetramethoxybenzophenone, and other benzophenones; anthraquinones, such as t-butylanthraquinone and 2-ethylanthraquinone; thioxanthones, such as 2,4-diethylthioxanthone, isopropylthioxanthone, and 2,4-dichlorothioxanthone; Michler's ketone; diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propan-1-one, 2-methyl-1-( acetophenones such as 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, trichloroacetophenone, etc.; benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, etc.; acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, etc.; methylbenzoyl formate; 1,7-bisacridinylheptane; 9-phenylacridine; azo compounds such as azobisisobutyronitrile, diazonium compounds, and tetrazene compounds. These may be used alone or in combination of two or more.

[0122] From the viewpoints of preventing breakage of the flexographic printing original plate finally obtained and preventing damage to the relief surface due to the load when the film for producing a printing plate of this embodiment is peeled off after exposure, the content of the photopolymerization initiator (b-3) in the photosensitive resin composition layer is preferably 0.1% by mass or more and 10% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, and even more preferably 0.3% by mass or more and 5% by mass or less, when the total amount of the photosensitive resin composition layer is taken as 100% by mass.

[0123] <Auxiliary Additive Components> Examples of auxiliary additive components include, but are not limited to, plasticizers, thermal polymerization inhibitors, antioxidants, light stabilizers, ultraviolet absorbers, dyes and pigments.

[0124] Examples of plasticizers include, but are not limited to, 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 naphthenic oil and paraffin oil; liquid diene-based conjugated diene rubbers such as liquid acrylonitrile-butadiene copolymer and liquid styrene-butadiene copolymer; polystyrene having a number average molecular weight of 2000 or less; and ester-based plasticizers such as sebacate esters and phthalate esters.

[0125] These plasticizers may have a hydroxyl group or a carboxyl group. Furthermore, these plasticizers may have a photopolymerizable reactive group such as a (meth)acryloyl group. The plasticizers may be used alone or in combination of two or more.

[0126] In this specification, the term "liquid" refers to a state that has the property of being easily fluid and deformable, and being able to be solidified into the deformed shape by cooling.

[0127] The content of the plasticizer in the photosensitive resin composition layer is preferably from 0% to 30% by mass, more preferably from 8% to 30% by mass, and even more preferably from 8% to 25% by mass, when the total amount of the photosensitive resin composition layer is taken as 100% by mass, from the viewpoints of improving the flexibility of the obtained flexographic printing original plate and preventing damage to the ablation layer and elution into the photosensitive resin composition layer when the film for producing a printing plate of this embodiment is peeled off after exposure.

[0128] As the thermal polymerization inhibitor and antioxidant, those commonly used in the field of resin materials or rubber materials can be used, and examples thereof include phenolic materials.

[0129] Examples of phenolic materials that are thermal polymerization inhibitors and antioxidants include, but are not limited to, vitamin E, tetrakis-(methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate)methane, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-p-cresol, 3,9-bis-{1,1-dimethyl-2-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro(5,5)undecane, and 2-t-butyl-6-(3-t-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate.

[0130] Other thermal polymerization inhibitors and antioxidants include, for example, phosphine-based materials such as triphenyl phosphite.

[0131] The thermal polymerization inhibitor and the antioxidant may be used alone or in combination of two or more.

[0132] Examples of light stabilizers and ultraviolet absorbers include, but are not limited to, known benzophenone compounds, salicylate compounds, acrylonitrile compounds, metal complex salt compounds, and hindered amine compounds.

[0133] The dyes and pigments shown below may also be used as ultraviolet absorbers.

[0134] Examples of such light stabilizers and ultraviolet absorbers include, but are not limited to, 2-ethoxy-2'-ethyloxalic acid bisanilide, 2,2'-dihydroxy-4-methoxybenzophenone, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-decanedioate, and 1,2,3-benzotriazole.

[0135] Dyes and pigments are effective as coloring means for improving visibility.

[0136] Examples of dyes include, but are not limited to, water-soluble basic dyes, acid dyes, direct dyes, etc., and water-insoluble sulfur dyes, oil-soluble dyes, disperse dyes, etc. Anthraquinone dyes, indigoid dyes, and azo dyes are particularly preferred.

[0137] Examples of pigments include, but are not limited to, natural pigments, synthetic inorganic pigments, synthetic organic pigments, etc. Examples of synthetic organic pigments include azo pigments, triphenylmethane pigments, quinoline pigments, anthraquinone pigments, and phthalocyanine pigments.

[0138] [Method for producing a flexographic printing plate] A preferred embodiment of the method for producing a flexographic printing plate according to this embodiment will be described below, but the method for producing a flexographic printing plate according to this embodiment is not limited to the following embodiment.

[0139] The method for producing a flexographic printing plate of this embodiment preferably uses the laminate of this embodiment described above.

[0140] As described above, the laminate has a configuration in which a flexographic printing plate precursor having a photosensitive resin composition layer and the film for producing a flexographic printing plate of this embodiment are laminated together.

[0141] The method for producing a flexographic printing plate of this embodiment includes a drawing step of irradiating the film for producing a flexographic printing plate with infrared rays to draw a pattern, an exposure step of irradiating the photosensitive resin composition layer with ultraviolet rays using the ablation layer on which the pattern has been drawn in the drawing step as a mask to form a pattern, and a development step of removing the unexposed areas of the photosensitive resin composition layer.

[0142] In the printing pattern drawing step in the method for producing a flexographic printing plate of this embodiment, the target of infrared irradiation may be the film for producing a flexographic printing plate that constitutes the laminate, or may be a film for producing a flexographic printing plate in a stage prior to forming the laminate. In other words, the film for producing a flexographic printing plate that constitutes the laminate of this embodiment includes both a state before and a state after pattern drawing.

[0143] More specifically, the method for producing a flexographic printing plate of this embodiment includes a first step of irradiating ultraviolet light from the support side of the flexographic printing original plate constituting the laminate of this embodiment, a second step of irradiating infrared light onto the ablation layer of the film for producing a flexographic printing plate to form a pattern, an exposure step of irradiating ultraviolet light onto the photosensitive resin composition layer using the ablation layer on which the pattern has been drawn as a mask to form a pattern, and a fourth step of developing to remove unexposed areas of the photosensitive resin composition layer.

[0144] Thereafter, a post-exposure treatment step is carried out as necessary, to obtain a flexographic printing plate made of a cured product of the photosensitive resin composition layer.

[0145] In the above-described method for producing a flexographic printing plate, the film for producing a flexographic printing plate that constitutes the laminate in the second step is in a state before pattern drawing, and the film for producing a flexographic printing plate that constitutes the laminate in the third step is in a state after pattern drawing.

[0146] From the viewpoint of imparting releasability, the surface of the flexographic printing plate may be brought into contact with a liquid containing a silicone compound and / or a fluorine compound.

[0147] 2 is a schematic diagram showing a method for producing a flexographic printing plate using the film for producing a flexographic printing plate of this embodiment. Each step will be described in detail below.

[0148] (First Step) In the first step, the photosensitive resin composition layer 4 is irradiated with ultraviolet light from the support 3 side of the flexographic printing plate precursor.

[0149] The ultraviolet irradiation method is not particularly limited, and can be carried out using a known irradiation unit. The wavelength of the ultraviolet light to be irradiated is preferably 150 to 500 nm, more preferably 300 to 400 nm.

[0150] Examples of ultraviolet light sources that can be used include, but are not limited to, low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, xenon lamps, zirconium lamps, carbon arc lamps, and ultraviolet fluorescent lamps.

[0151] The first step may be carried out before or after the second step described below.

[0152] (Second Step) In the second step, infrared rays are irradiated onto the ablation layer 2 of the film for producing a flexographic printing plate to form a pattern. The method for forming the pattern is not particularly limited, and can be carried out using a known irradiation unit. The infrared rays can be irradiated onto the ablation layer 2 from the ablation layer 2 side.

[0153] The ablation layer 2 is irradiated with infrared rays in a pattern, which decomposes the resin in the irradiated areas and creates a pattern. This forms an ablation layer mask on the film for producing flexographic printing plates. This results in an ablation layer 2' with a pattern created.

[0154] Examples of infrared lasers used in the second step include ND / YAG lasers (e.g., 1064 nm) and diode lasers (e.g., 830 nm). Laser systems suitable for CTP platemaking technology are commercially available, and for example, the diode laser system CDI Spark (ESKO GRAPHICS) can be used. This laser system includes a rotating cylindrical drum that holds a film for producing flexographic printing plates, an IR laser irradiation device, and a layout computer, and image information is sent directly from the layout computer to the laser device.

[0155] In the method for producing a flexographic printing plate of this embodiment, the second step may be performed in a state where the film for producing a flexographic printing plate is laminated on the photosensitive resin composition layer, or may be performed at a stage before being laminated on the photosensitive resin composition layer.

[0156] (Third Step) In the third step, the photosensitive resin composition layer 4 is exposed to ultraviolet light using the pattern-drawn ablation layer 2' as a mask.

[0157] At this time, the light passing through the mask promotes the curing reaction of the photosensitive resin composition layer 4, and the pattern formed in the ablation layer 2′ is transferred to the photosensitive resin composition layer 4 with the concaves and convexes reversed, thereby obtaining a pattern-exposed photosensitive resin composition layer 4′. The ultraviolet irradiation may be performed on the entire surface or on a part of the surface.

[0158] The front and back sides of the film for producing flexographic printing plates of this embodiment can be used without any particular restrictions, but from the viewpoint of reducing the effects of bending and scattering of ultraviolet light irradiated onto the photosensitive resin composition layer, it is preferable to arrange the surface of the film for producing flexographic printing plates on the side of the patterned ablation layer 2' so that it is in contact with the photosensitive resin composition layer.

[0159] It is preferable that the surface on the ablation layer 2' side be in direct contact with the photosensitive resin composition layer, which reduces the oxygen concentration gradient between the surface and the interior of the photosensitive resin, making it possible to create fine images even with a liquid resin that has been stored for a long period of time.

[0160] On the other hand, for purposes including protection of the photosensitive resin composition layer and surface treatment, a separate film may be provided between the film for producing a flexographic printing plate on which a pattern has been drawn and processed and the photosensitive resin composition layer 4.

[0161] Furthermore, one or more intermediate layers may be further provided between the photosensitive resin composition layer 4 and the ablation layer 2′. Examples of the intermediate layer include, but are not limited to, an oxygen inhibition layer, an adhesive layer, and a protective layer.

[0162] Each layer will be described below.

[0163] In order to produce a high-definition print having highlight areas, it is necessary to form minute dots on the flexographic printing plate. From the viewpoint of forming such minute dots, the intermediate layer is preferably an oxygen inhibition layer having oxygen inhibition ability.

[0164] If oxygen inhibits the radical polymerization reaction when the photosensitive resin composition layer 4 is cured by irradiation with ultraviolet light, there is a risk that unreacted portions will remain in the exposed areas of the photosensitive resin composition layer 4. These unreacted portions will be removed in the fourth step described below, and the pattern finally formed on the flexographic printing plate will have a shape with curved portions at its leading edge. This is because the portion of the photosensitive resin composition layer 4 on the ablation layer 2' side is particularly susceptible to polymerization inhibition by oxygen, and unreacted portions are likely to occur in the photosensitive resin composition layer 4 directly below the ablation layer 2'.

[0165] On the other hand, if the amount of oxygen present during UV curing is reduced, the polymerization reaction is less likely to be suppressed, and the pattern that is finally formed will have a shape with flat portions at the tip. Therefore, when attempting to produce a pattern with flat portions at the tip, it is preferable that the intermediate layer has oxygen inhibition ability, which makes it possible to reduce the amount of oxygen that comes into contact with the photosensitive resin composition layer 4.

[0166] The intermediate layer may also be an adhesive layer that improves the adhesion between the photosensitive resin composition layer 4 and the ablation layer 2'.

[0167] Furthermore, the intermediate layer may also have a function of protecting the ablation layer 2'. In the above-described manufacturing process of a flexographic printing plate, when the photosensitive resin composition layer 4 is laminated on the film for manufacturing a flexographic printing plate or when the film is handled, the ablation layer 2' may come into contact with the worker's fingers or tools, which may physically damage the ablation layer 2' and cause scratches or pinholes.

[0168] In order to prevent such damage to the ablation layer 2', it is preferable that the intermediate layer has the physical strength and heat resistance required for a protective layer.

[0169] (Fourth Step) The fourth step is a step of removing the unexposed areas of the pattern-exposed photosensitive resin composition layer 4'.

[0170] In the fourth step (development step), the method for removing the unexposed areas is not particularly limited, and any conventionally known method can be applied.

[0171] Specific methods include, for example, a method of exposing the photosensitive resin composition layer 4 to light and then washing away the unexposed portions with a solvent for solvent development or a cleaning solution for water development, or a method of bringing the unexposed portions into contact with a predetermined absorbing layer capable of absorbing the light and removing the absorbing layer to remove the unexposed portions. Note that, as a pre-removal step, the unexposed portions may be removed in advance using a spatula or roll. Thereafter, a post-exposure treatment is performed as necessary to produce a flexographic printing plate.

[0172] When an intermediate layer is present between the ablation layer 2' and the photosensitive resin composition layer 4', it may be removed simultaneously in the development step.

[0173] When the photosensitive resin composition is in a liquid state at room temperature, the first to third steps described above usually include a predetermined molding step in which the photosensitive resin composition is molded into a film of a certain thickness on a support inside a dedicated device (plate making machine).

[0174] As described above, in the exposure step when using a photosensitive resin composition that is liquid at room temperature, it is preferable to carry out, for example, each of the following steps (A1) to (A3).

[0175] (A1): In step (A1), a film for producing a flexographic printing plate, on which a mask has been formed by pattern drawing processing, is placed on an ultraviolet-transmitting glass plate (lower glass plate), a photosensitive resin composition is poured onto it, and a base film serving as a support is laminated to the film via a spacer so that the resulting plate has a constant plate thickness. The film is then pressed down with an ultraviolet-transmitting glass plate (upper glass plate) from above to form a photosensitive resin composition layer.

[0176] In this step (A1), after placing the film for producing a flexographic printing plate on the lower glass plate, it is preferable to evacuate the film in order to reliably fix the film for producing a flexographic printing plate and to remove oxygen-inhibiting factors. The mechanism for evacuating the film is not particularly limited, but examples thereof include a method of evacuating the film with a pump through a groove provided around the periphery of the lower glass.

[0177] If the rigidity of the film for producing a flexographic printing plate is insufficient, the film for producing a flexographic printing plate will wrinkle during the vacuuming process, and in severe cases, the wrinkles will remain and cannot be removed. The wrinkles that are generated will be transferred to the relief surface after curing, which may significantly reduce image reproducibility. Furthermore, if the dimensional stability of the film for producing a flexographic printing plate is insufficient, the drawn pattern will be deformed, which also contributes to reducing image reproducibility.

[0178] On the other hand, if the rigidity of the film for producing flexographic printing plates is too high, it will not be able to completely conform to the lower glass during evacuation, leaving a gap and allowing air to remain. As a result, the effects of oxygen inhibition may become greater, which may adversely affect image reproducibility. Furthermore, stress generated by deformation of the highly elastic film for producing flexographic printing plates may be concentrated in the ablation layer, causing wrinkles and pinholes. In other words, it is extremely important that the film for producing flexographic printing plates of this embodiment has a rigidity within an appropriate range.

[0179] It is also possible to provide a separate film between the film for producing a flexographic printing plate on which a pattern has been drawn and processed and the photosensitive resin composition. However, from the viewpoint of enabling the production of fine images even with a photosensitive resin composition that has been stored for a long period of time, it is preferable to have the film for producing a flexographic printing plate and the photosensitive resin composition in direct contact with each other.

[0180] When preparing a flexographic printing plate (having a thickness of 4 mm or more) for use in corrugated board printing, it is preferable to form a shelf layer serving as a base in the portion of the photosensitive resin composition layer on the upper glass plate side in order to compensate for the strength of the relief against the printing pressure during printing. 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.

[0181] (A2): In step (A2), after the molding step of the photosensitive resin composition layer, back exposure is performed to deposit a uniform thin cured resin layer (i.e., floor-forming layer (back deposition layer)) over the entire surface of the base film side of the plate by irradiating the plate with actinic rays (e.g., rays having a wavelength distribution of 300 nm or more) from an ultraviolet fluorescent lamp or the like as an actinic light source through the base film from the upper glass plate side.

[0182] When a masking film is provided in the photosensitive resin composition layer forming step, the shelf layer is formed by similar exposure, which is referred to as a masking exposure step.

[0183] The back deposition layer and the shelf layer are both formed by curing the photosensitive resin composition layer on the side opposite to the relief-forming layer side, i.e., on the support side. When the entire photosensitive resin composition layer on the support side is cured, a back deposition layer is formed, and when the photosensitive resin composition layer is partially cured depending on the position of the relief-forming layer, a shelf layer is formed.

[0184] (A3): In step (A3), after the back exposure step or the masking exposure step, the photosensitive resin composition layer is irradiated with actinic rays similar to those in (A2) above from the lower glass side through a film for producing a flexographic printing plate on which a mask has been formed by pattern drawing processing, to precipitate an image-forming layer (relief-forming layer), and relief-forming exposure is performed.

[0185] In addition, when a shelf layer is formed by a masking exposure process, one preferred embodiment is to remove the masking film after the relief formation exposure and then perform a back exposure process to form a back deposition layer over the entire surface of the base film.

[0186] 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 in any way.

[0187] [Measurement of water contact angle of substrate] Using a contact angle meter AD-31 (manufactured by Kyowa Interface Science Co., Ltd.), 0.2 mL of distilled water was dropped onto any surface of the substrate, and after leaving it to stand for 3 minutes, the contact angle was measured at n = 5 points or more, and the average value was used. If an ablation layer is laminated on the substrate, the ablation layer is removed before measurement.

[0188] [Film for producing flexographic printing plates, and production of flexographic printing plates] In the following examples and comparative examples, a film for producing flexographic printing plates was prepared, and a flexographic printing plate was produced using the film for producing flexographic printing plates.

[0189] (1) Production of Resin Used in Ablation Layer Production of Resin 1 250 parts by mass of isophthalic acid, 300 parts by mass of terephthalic acid, 130 parts by mass of azelaic acid, 150 parts by mass of ethylene glycol, and 170 parts by mass of neopentyl glycol were charged into a flask, and an esterification reaction and distillation of water were carried out at 200°C for 8 hours. Then, 0.01 parts by mass of tetraisobutyl titanate was added, and the pressure was gradually reduced. The mixture was heated at 1 mmHg and 230°C for 6 hours to distill off a portion of the glycol component and carry out a transesterification reaction. A mixture of ethyl acetate / methyl ethyl ketone = 5 / 1 mixed solvent was used to give a solids content of 50%, and Resin 1, a polyester polyol having a number average molecular weight of 20,000, was obtained.

[0190] <Production of Resins 2 to 5> Resins 2 to 5 were obtained under the same conditions as for Resin 1 except that the parts by mass of isophthalic acid, terephthalic acid, and azelaic acid were changed as shown in Table 1 below.

[0191]

[0192] (2) Production of Film for Flexographic Printing Plate Production <Production of Film for Flexographic Printing Plate Production of Example 1> 7.8 parts by mass of Resin 1, 70.0 parts by mass of toluene, and 18.0 parts by mass of cyclohexanone were mixed to dissolve Resin 1 in the solvent. Then, 4.0 parts by mass of Carbon Black #30 (manufactured by Mitsubishi Chemical Corporation) and 0.7 parts by mass of Solsperse S39000 (manufactured by The Lubrizol Corporation) were further added, and the mixture was mixed for 4 hours in a bead mill to obtain a carbon black dispersion. The carbon black dispersion obtained as described above was mixed and dissolved with 1.9 parts by mass of a curing agent prepared by adjusting the solid content of trimethylolpropane (1 mol) to tolylene diisocyanate (3 mol) with ethyl acetate to 50% and 0.5 parts by mass of Auroren 350S (manufactured by Nippon Paper Industries Co., Ltd.). The mixture was then coated onto a substrate 1 shown in Table 3 so that the film thickness after drying would be 2.5 μm. The coating was then dried at 90° C. for 2 minutes and then aged at 20° C. for 24 hours to obtain a film for producing a flexographic printing plate, which is a laminate of an ablation layer 1 and a substrate 1.

[0193] <Production of films for producing flexographic printing plates in Examples 5 to 14 and Comparative Examples 1 and 2> The composition of the ablation layer was changed as shown in Table 2. Other conditions were the same as those for the film for producing flexographic printing plates in Example 1, and films for producing flexographic printing plates, which were laminates of the ablation layer and the substrate, were obtained.

[0194] <Production of films for producing flexographic printing plates in Examples 2 to 4 and Comparative Example 3> The composition of the ablation layer was changed as shown in Table 2. In addition, the substrate used was changed to the substrate shown in Table 3. Other conditions were the same as for the film for producing flexographic printing plates in Example 1, and films for producing flexographic printing plates, which were laminates of the ablation layer and the substrate, were obtained.

[0195]

[0196]

[0197] (3) Laser writing on film for producing flexographic printing plates) The film for producing flexographic printing plates was placed on an Esko CDI Crystal 5080, and laser writing was performed on the ablation layer with a test image having the image pattern described below at a resolution of 8000 dpi and a laser intensity of 2.2 J.

[0198] Using the film for producing a flexographic printing plate after image drawing, a flexographic printing plate was produced by sequentially undergoing the forming / exposing step, the developing step, the post-exposing step, and the drying step as shown in (4) to (7) below.

[0199] ((4) Molding and Exposure Step) <Molding and Exposure Steps of Examples 1 to 14 and Comparative Examples 1 to 3> Molding and exposure were carried out using an "ALF-213E plate making machine" manufactured by Asahi Kasei Corporation according to (A1) to (A3). In addition, Tenaflex (registered trademark, manufactured by Asahi Kasei Corporation) was used as the liquid photosensitive resin.

[0200] (A1): The film for producing a flexographic printing plate after image drawing was placed on an ultraviolet-transmitting lower glass plate so that the ablation layer after image drawing was located on the opposite side of the lower glass plate, with the substrate sandwiched between them. A vacuum was then drawn with a pump through a groove provided around the periphery of the lower glass plate to fix the film for producing a flexographic printing plate. A photosensitive resin was then laminated on top of the film, and a base film serving as a support was attached via a spacer to ensure a constant plate thickness. An ultraviolet-transmitting glass plate (upper glass plate) was then pressed down from above to form a photosensitive resin layer. Before relief exposure, a dedicated masking film was sandwiched between the upper glass plate and the base film to form the photosensitive resin layer.

[0201] (A2): After the photosensitive resin layer was formed, actinic rays (light having a wavelength distribution of 300 nm or more) from an ultraviolet fluorescent lamp or the like as an actinic light source were irradiated through the base film from the upper glass plate side. Because a masking film was provided in the photosensitive resin layer formation process, masking exposure was performed by the same exposure, and a shelf layer was formed.

[0202] (A3): After the masking exposure step, a relief-forming exposure step was carried out in which the photosensitive resin layer was irradiated with actinic rays similar to those used in the upper step from the lower glass side through the film for producing a flexographic printing plate after image drawing, thereby forming an image, thereby obtaining a flexographic printing plate precursor.

[0203] A photosensitive resin layer was formed using (A1) as described above. The test image and masking film used were designed to form linear unexposed areas (hereinafter referred to as "voids" or "void lines") of 100 μm width and 500 μm width within a 300 mm × 500 mm shelf layer and a 200 mm × 250 mm solid image, respectively.

[0204] Next, the photosensitive resin layer was exposed to light in the above (A2) and (A3) to obtain a flexographic printing original plate having a plate thickness of 3 mm and a relief depth of 1.5 mm. Here, the relief depth is the length obtained by subtracting the height of the shelf layer from the plate thickness, i.e., the depth of the printing image relief.

[0205] To adjust the relief depth, the masking exposure dose was adjusted appropriately. The relief exposure dose was 600 mJ / cm ２ The relief was formed under the following conditions.

[0206] <Forming and exposure process of Example 15> The film for producing a flexographic printing plate after image formation was placed on a lower glass plate, and then covered with a separate protective film (OPP film with a thickness of 20 μm). The protective film was fixed in place by evacuating with a pump through a groove provided around the periphery of the lower glass plate. Relief formation was carried out under the same conditions as in Example 1.

[0207] ((5) Development step) After image drawing, the film for producing a flexographic printing plate was peeled from the flexographic printing plate blank, and the unexposed photosensitive resin was removed from the flexographic printing plate blank using a rubber spatula. Thereafter, using an "AL-400W type developing machine" manufactured by Asahi Kasei Corporation (drum rotation spray type, drum rotation speed: 20 rpm, spray pressure: 0.15 Pa), development was carried out under the conditions of a liquid temperature of 40 ° C. and a development time of 10 minutes using an aqueous solution containing 2% by mass of "APR (registered trademark) Cleaning Agent Type W-10" manufactured by Asahi Kasei Corporation (main component: anionic surfactant), 0.5% by mass of "APR (registered trademark) Surface Treatment Agent Type A-10" manufactured by Asahi Kasei Corporation (main component: nonionic surfactant, benzophenone), and 0.3% by mass of "Antifoaming Agent SH-4" manufactured by Asahi Kasei Corporation (silicone mixture). After development, the film was washed with tap water until bubbles from the developer were removed.

[0208] (6) Post-exposure step) Post-exposure was carried out by the underwater exposure method using an "AL-200UP type post-exposure machine" manufactured by Asahi Kasei Corporation, which is equipped with both an ultraviolet fluorescent lamp and a germicidal lamp. The exposure dose from each light source was as follows on the photosensitive resin surface: ultraviolet fluorescent lamp: 2000 mJ / cm ２ , Germicidal lamp: 2000mJ / cm ２ The exposure was carried out for an exposure time of .

[0209] (7) Drying Step) Using an "ALF-DRYER" manufactured by Asahi Kasei Corporation, the post-exposed plate was dried for about 30 minutes until all moisture on the surface was removed, to obtain a flexographic printing plate.

[0210] <Preparation of Flexographic Printing Plate of Example 16> The following photosensitive resin composition plate was used. Solvent-developable, non-exposed photosensitive resin composition plate AFP-SE (registered trademark, manufactured by Asahi Kasei Corporation): The support is a polyester film, and the photosensitive resin composition layer contains a styrene-butadiene block copolymer as the main component, a polymerizable monomer component, a photopolymerization initiator, a plasticizer, and a thermal polymerization inhibitor, and has a thin, flexible film layer. The thickness is 1.7 mm.

[0211] The cover sheet was peeled off from the photosensitive resin composition plate, and the film for producing a flexographic printing plate after image drawing was adhered so that the ablation layer was in contact with the photosensitive resin composition layer. Using an "AFP-1216E" exposure machine (manufactured by Asahi Kasei Corporation, product name), a lower ultraviolet lamp (UV lamp TL80W / 10R, product name, manufactured by PHILIPS) was used to first expose the flexographic printing plate from the support side to 600 mJ / cm so that the relief depth of the flexographic printing plate would be 1.5 mm. ２ The entire surface was exposed.

[0212] Subsequently, an upper lamp (a UV lamp TL80W / 10R, product name, manufactured by PHILIPS) was used to apply 8000 mJ / cm from the side of the film for producing flexographic printing plates after the image was drawn. ２ The exposure intensity was measured using a UV illuminance meter MO-2 manufactured by Oak Manufacturing Co., Ltd. (trade name, UV-35 filter, manufactured by Oak Manufacturing Co., Ltd.).

[0213] Next, development was carried out at a predetermined speed at a liquid temperature of 30° C. using an "AFP-1321P" developing machine (trade name, manufactured by Asahi Kasei Corporation), and the film was dried at 60° C. for 2 hours.

[0214] Thereafter, as a post-exposure treatment, an AFP-1216LF (trade name, manufactured by Asahi Kasei Corporation) was used to apply 1000 mJ / cm to the entire surface of the dried plate using a germicidal lamp (GL-30, trade name, manufactured by Toshiba Corporation) with a central wavelength of 254 nm. ２ The post-exposure dose using the germicidal lamp was calculated from the illuminance measured using a UV-25 filter on a "UV-MO2" machine.

[0215] [Evaluation of Films for Producing Flexographic Printing Plates and Flexographic Printing Plates] <Evaluation of Scratch Resistance of Ablation Layer> A pencil hardness test was performed on the ablation layer of the film for producing flexographic printing plates using a Clemens scratch hardness tester (manufactured by Tester Sangyo Co., Ltd.) at a speed of 5 mm / sec, a scratch width of 4 cm, and a load of 200 g, and the appearance was observed.

[0216] According to the following evaluation criteria, A to D were evaluated as being usable in practice without any problems. A: When the hardness was 4H or less and no film peeling occurred B: When the hardness was 3H or less and no film peeling was observed C: When the hardness was 2H or less and no film peeling was observed D: When the hardness was H or less and no film peeling was observed E: When the hardness was H or less and film peeling was observed

[0217] <Evaluation of Aged Film for Flexographic Printing Plate Production (Film PH)> A polyethylene interleaf was laminated on the ablation layer of the film for flexographic printing plate production, and the film was stored for one month under a load of 2 kg in a thermo-hygrostat PH-3K (manufactured by ESPEC Corporation) set at a temperature of 40°C and a relative humidity of 80% RH. The interleaf was peeled off, and a field of view of 20 cm x 20 cm was observed with a microscope (manufactured by Keyence, VHX-1000) at a magnification of 50 times. The number of pinholes with a major axis of 100 μm or more in the infrared ablation layer was counted, and the average value was calculated (numbers / m ２ ) values ​​were calculated.

[0218] In the following evaluation criteria, A to D were evaluated as being usable without any problems in practice. A: Average 1 (pieces / m ２ ) less than B: average 1 (pieces / m ２ ) or more 2 (pcs / m ２ ) less than C: average 2 (pieces / m ２ ) or more 5 (pcs / m ２ ) Less than D: Average 5 (pieces / m ２ ) or more 10 (pieces / m ２ ) Less than E: Average 10 (pieces / m ２ ) or more, or the ablation layer is transferred to the slip sheet

[0219] <Evaluation of the depth of outlines (100 μm line depth) of flexographic printing plates using aged photosensitive resin> A liquid photosensitive resin or a photosensitive resin composition plate was stored for one month in a thermo-hygrostat PH-3K (manufactured by ESPEC Corporation) set at a temperature of 40°C and a relative humidity of 80% RH. A flexographic printing plate was then obtained using the same method as in Example 1 for producing a flexographic printing plate. The groove shapes of outlines with 100 μm and 500 μm line widths were observed using a μDEPTH & HEIGHT MEASURING SCOPE KY-90 (manufactured by Nissho Precision Optical Co., Ltd.). The depth of the 100 μm line width was measured when the depth of the 500 μm line width was 150 μm. The evaluation criteria for the measurement results are shown below.

[0220] According to the following evaluation criteria, A to D were evaluated as being usable without any problems in practice: A: Depth of 50 μm or more B: Depth of 40 μm or more and less than 50 μm C: Depth of 30 μm or more and less than 40 μm D: Depth of 20 μm or more and less than 30 μm E: Depth less than 20 μm

[0221]

[0222]

[0223] REFERENCE SIGNS LIST 1: Substrate 2: Ablation layer 2': Pattern-drawn ablation layer 3: Support 4: Photosensitive resin composition layer 4': Pattern-exposed photosensitive resin composition layer

Claims

1. A film for manufacturing a flexographic printing plate, comprising a substrate and an ablation layer laminated on the substrate, wherein the surface of the substrate in contact with the ablation layer contains a resin having a polyolefin backbone, and the ablation layer contains: polyurethane composed of a polyol and a polyisocyanate; and a modified polyolefin.

2. The film for manufacturing a flexographic printing plate according to claim 1, wherein the water contact angle of the surface of the substrate in contact with the ablation layer is 80° or more.

3. The film for manufacturing a flexographic printing plate according to claim 1, wherein the weight ratio of the polyurethane to the modified polyolefin is 2.0 to 50.

0.

4. The film for manufacturing a flexographic printing plate according to claim 1, wherein the ratio (NCO / OH) of the number of moles of isocyanate groups of the polyisocyanate to the number of moles of hydroxy groups of the polyol is 4.0 or more.

5. The film for manufacturing a flexographic printing plate according to claim 1, wherein the ratio (NCO / OH) of the number of moles of isocyanate groups of the polyisocyanate to the number of moles of hydroxy groups of the polyol is 8.0 or more.

6. The film for manufacturing a flexographic printing plate according to claim 1, wherein the number of isocyanate groups contained in the polyisocyanate is 3 or more per molecule.

7. The film for manufacturing a flexographic printing plate according to claim 1, wherein the polyol contains a polyester polyol, the polyester polyol contains a structural unit derived from a diol, a structural unit derived from an aromatic dicarboxylic acid, and a structural unit derived from an aliphatic dicarboxylic acid, and the molar ratio of the aromatic dicarboxylic acid to the aliphatic dicarboxylic acid is 1.0 to 50.

0.

8. A method for manufacturing a flexographic printing plate, comprising: a drawing step of irradiating infrared rays to the ablation layer of the film for manufacturing a flexographic printing plate according to any one of claims 1 to 7 to draw a pattern; and an exposure step of irradiating ultraviolet rays to the photosensitive resin composition layer of the flexographic printing original plate using the ablation layer in which the pattern has been drawn in the drawing step as a mask to form a pattern.

9. The manufacturing method according to claim 8, wherein in the exposure step, the ablation layer and the photosensitive resin composition layer are in direct contact with each other.

10. The manufacturing method according to claim 8, wherein the photosensitive resin composition layer is liquid under the condition of 10 to 60°C.

Images