Photosensitive resin composition for relief printing original plate, relief printing original plate, and printing plate

Abstract

The invention provides a photosensitive resin composition for a relief printing original plate, a relief printing original plate, and a printing plate. The photosensitive resin composition for the relief printing original plate can reduce development change of the relief printing original plate in a high-temperature environment, can realize satisfactory reproducibility in a resin relief plate in a high-temperature environment, and can reduce poor printing when the resin relief plate is used for printing in a low-temperature environment. The photosensitive resin composition for a relief printing original plate contains (a) a polyamide and / or a polyamide block copolymer, (b) a crosslinking agent having one or more unsaturated groups, (c) a photopolymerization initiator, and (d) a polyglycerol and / or a polyglycerol derivative obtained by the addition polymerization of polyglycerol with ethylene oxide or propylene oxide, the content of (d) in the photosensitive resin composition is 3-15% by weight.

Description

Technical Field

[0001] The present invention relates to a photosensitive resin composition for relief printing original plate, relief printing original plate and printing plate. Background Art

[0002] The photosensitive resin composition used for the printing original plate generally contains a soluble high molecular compound, a photopolymerizable unsaturated compound and a photopolymerization initiator, and may contain additives such as a stabilizer and a plasticizer as required.

[0003] It is widely known that a relief plate for printing can be produced by selectively curing a photosensitive resin layer obtained from a photosensitive resin composition by irradiating it with active light through a negative film having a transparent image area, dissolving and removing the uncured portion with an appropriate solvent, and then drying and post-exposing it.

[0004] As the soluble polymer compound, it has been proposed to use soluble polyamide or completely saponified or partially saponified polyvinyl acetate.

[0005] In recent years, users' requirements for relief printing originals have been moving towards the direction of being able to reproduce ultra-fine patterns. In the developed printing plate, for the minimum highlight area used for printing photos, it is required to have reproducibility of brightness (gradation of highlight dots) that changes smoothly at a printing size close to the negative size, with less than 5% of 150 lines.

[0006] In response to the demand for fine highlight dot printability, there have been proposed a relief printing original that improves image reproducibility by having a photosensitive resin layer composed of multiple layers with different light transmittances (see Patent Document 1), a relief printing original that sharpens the relief shape by multi-layering the photosensitive resin layer (see Patent Document 2), and a relief printing original that uses a polyamide obtained by copolymerizing an alicyclic dicarboxylic acid and an alicyclic diamine for the photosensitive resin layer (see Patent Document 3). Prior art literature Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2002-23349 Patent Document 2: Japanese Patent Application Laid-Open No. 06-313966 Patent Document 3: International Publication No. 2017 / 056692 Summary of the invention Problem that the invention aims to solve

[0008] In various countries around the world, printing plates (hereinafter also referred to as resin relief plates) are made from relief printing original plates obtained from photosensitive resin compositions for relief printing original plates, and printing is performed using resin relief plates. In high temperature environments, the developability of relief printing original plates changes. In low temperature environments, poor winding of the resin relief plates on the plate body and cracking of the surface printing surface may occur during printing, which may lead to poor printing.

[0009] The present invention is made in view of the above situation, and its purpose is to provide a photosensitive resin composition for a relief printing original plate, a relief printing original plate and a printing plate, which can reduce the change in the developability of the relief printing original plate in a high temperature environment, achieve satisfactory reproducibility in the resin relief plate in a high temperature environment, and reduce printing defects when printing using the resin relief plate in a low temperature environment. Technical means of solving problems

[0010] To achieve the above object, the present inventors have found that a photosensitive resin composition capable of providing a plate with high environmental adaptability can be obtained by mixing a photosensitive resin composition for relief printing original plates with polyglycerol and / or a polyglycerol derivative, thereby completing the present invention. That is, the present invention may include the following inventions. [1] A photosensitive resin composition for a relief printing original plate, which is a photosensitive resin composition for a relief printing original plate, the photosensitive resin composition comprising (a) polyamide and / or polyamide block copolymer, (b) a crosslinking agent having one or more unsaturated groups, (c) a photopolymerization initiator, and (d) polyglycerol and / or a polyglycerol derivative, wherein the polyglycerol derivative is obtained by addition polymerization of polyglycerol with ethylene oxide or propylene oxide, and the content of (d) in the photosensitive resin composition is 3 to 15% by weight. [2] The photosensitive resin composition for relief printing original plate according to [1], wherein the number average molecular weight of each of the polyglycerol and the polyglycerol derivative (d) is 300 or more. [3] The photosensitive resin composition for relief printing original plate according to [1], wherein the photosensitive resin composition contains a polyglycerol derivative (d), wherein the polyglycerol derivative (d) is a polyoxyethylene polyglycerol ether and / or a polyoxypropylene polyglycerol ether having a number average molecular weight of 300 or more. [4] According to the photosensitive resin composition for relief printing original plate described in [1] to [3], the photosensitive resin composition contains 40 to 60% by weight of (a) polyamide and / or polyamide block copolymer, 20 to 50% by weight of (b) a cross-linking agent having one or more unsaturated groups, and 0.1 to 10% by weight of (c) a photopolymerization initiator; (a) polyamide and / or polyamide block copolymer contains 20% by weight or more of structural units composed of amide bonds in the form of blocks in the molecule. [5] A relief printing original plate, comprising a support and a photosensitive resin layer composed of the photosensitive resin composition for a relief printing original plate according to any one of [1] to [4]. [6] A printing plate obtained by removing the uncured portion of the photosensitive resin layer from the relief printing original plate described in [5]. Effects of the Invention

[0011] According to the present invention, by including polyglycerol and / or polyglycerol derivatives having flexibility in the photosensitive resin composition, the change in the developability of the relief printing original plate under a high temperature environment can be reduced, satisfactory reproducibility can be achieved in the resin relief plate under a high temperature environment, and printing defects can be reduced when printing using the resin relief plate under a low temperature environment. DETAILED DESCRIPTION

[0012] Hereinafter, the photosensitive resin composition for relief printing original plate according to the present specification will be described in detail. The relief printing plate comprises a photosensitive resin layer composed of the photosensitive resin composition, an adhesive layer and a support. In the present specification, a numerical range represented by "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0013] The support is a flexible material, preferably a material having excellent dimensional stability, and examples thereof include metal supports such as steel, aluminum, copper, and nickel, and thermoplastic resin supports such as polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, and polycarbonate film. Among these, polyethylene terephthalate film having excellent dimensional stability and sufficiently high viscoelasticity is particularly preferred. From the perspective of mechanical properties, shape stabilization, and / or operability during printing plate making, the thickness of the support is preferably 50 to 350 μm, and more preferably 100 to 250 μm.

[0014] The adhesive layer is provided between the support and the photosensitive resin layer to improve the adhesion between the support and the photosensitive resin layer. The adhesive layer may be formed from one layer or multiple layers. The adhesive layer preferably contains, for example, an adhesive component and a pigment, and more preferably contains a leveling agent and a curing agent.

[0015] Examples of the binder component include polyester resins, epoxy resins, polyamide resins, polyimide resins, phenolic resins, butadiene resins, polyurethane resins, and polystyrene-polyisoprene copolymer resins, which can be used alone or in combination. Among these, polyester resins and polyurethane resins are particularly preferred from the viewpoint of solvent resistance.

[0016] The photosensitive resin layer is composed of a photosensitive resin composition. The photosensitive resin composition contains (a) polyamide and / or polyamide block copolymer, (b) a crosslinking agent having one or more unsaturated groups, (c) a photopolymerization initiator, and (d) polyglycerol and / or a polyglycerol derivative. In addition to the components (a) to (d), the photosensitive resin composition may further contain other additives such as a thermal polymerization inhibitor, a plasticizer, a dye, a pigment, a fragrance, and / or an antioxidant.

[0017] (a) Polyamide and / or polyamide block copolymer is a polymer compound containing 20% ​​by weight or more, preferably 30% by weight or more, of structural units consisting of amide bonds in a block form in the molecule. For example, polyether amide, polyether ester amide, tertiary nitrogen-containing polyamide, ammonium salt-type tertiary nitrogen atom-containing polyamide, addition polymer of an amide compound having one or more amide bonds and an organic diisocyanate, etc., among which ammonium salt-type tertiary nitrogen atom-containing polyamide is preferred. In addition, in the case of containing tertiary nitrogen atom-containing polyamide and ammonium salt-type tertiary nitrogen atom-containing polyamide, the developability is improved when an organic acid is contained. As organic acids, acetic acid, lactic acid, and methacrylic acid can be mentioned, but are not limited to these.

[0018] In addition to the amide bond, the polyamide block copolymer may also have a urea bond and / or a carbamate bond. In the commonly used UV ink, since the composition similar to the photosensitive resin composition for the printing original plate is used, the UV ink resistance of the photosensitive resin layer is poor. However, by using a polyamide and / or a polyamide block copolymer having an amide bond in the molecule in the photosensitive resin layer, the resistance of the photosensitive resin layer to UV ink can be improved. The proportion of component (a) in the photosensitive resin composition is preferably 40 to 60% by weight. In addition, from the viewpoint of imparting flexibility, the polyamide block copolymer may also contain polyalkylene glycol. As specific alkylene glycols, polyethylene glycol and copolymers thereof can be cited.

[0019] (b) As crosslinking agents having one or more unsaturated groups, for example, dipentaerythritol, pentaerythritol, trimethylolpropane, glycerol, ethylene glycol, diethylene glycol, triethylene glycol, ethylene oxide adducts of phthalic acid; diglycidyl ether acrylic acid adducts of bisphenol A or bisphenol F; addition reaction products of polyglycidyl ethers such as ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol penta(meth)acrylate, and dipentaerythritol penta(meth)acrylate with (meth)acrylic acid; reaction addition products of polycarboxylic acids such as adipic acid and glycidyl (meth)acrylate, addition reaction products of polyamines such as propylenediamine and glycidyl (meth)acrylate, etc., but the present invention is not limited to these. As component (b), not only a single compound but also a mixture of two or more compounds can be used. The ratio of the component (b) in the photosensitive resin composition is preferably 20 to 50% by weight.

[0020] Examples of the (c) photopolymerization initiator include benzophenones, benzoins, acetophenones, dibenzoyls, benzoin alkyl ethers, benzyl alkyl ketals, anthraquinones, and thioxanthones. Specifically, examples include benzophenone, chlorobenzophenone, benzoin, acetophenone, dibenzoyl, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, benzyl diethyl ketal, benzyl diisopropyl ketal, anthraquinone, 2-ethyl anthraquinone, 2-methyl anthraquinone, 2-allyl anthraquinone, 2-chloro anthraquinone, thioxanthones, and 2-chloro thioxanthones. The proportion of the (c) component in the photosensitive resin composition is preferably in the range of 0.1 to 10% by weight.

[0021] Regarding component (d), the following explanation is established. Polyglycerol has a repeating structure containing an ether bond, which helps the resin relief plate to maintain flexibility even in a low temperature environment. Polyglycerol derivatives are compounds obtained by polyaddition of polyglycerol with ethylene oxide or propylene oxide, and have a repeating structure containing an ether bond like polyglycerol, which helps the resin relief plate to maintain flexibility even in a low temperature environment. It is believed that this is because polyglycerol and polyglycerol derivatives, for example, are prone to molecular motion due to having a repeating structure containing an ether bond, and are difficult to crystallize.

[0022] The number average molecular weight of each polyglycerol and polyglycerol derivative is preferably greater than 300 and less than 3000. The number average molecular weight of each polyglycerol and polyglycerol derivative is more preferably greater than 350, further preferably greater than 500, and further preferably greater than 700. The number average molecular weight of each polyglycerol and polyglycerol derivative is more preferably less than 1500, further preferably less than 1000, and further preferably less than 800. The smaller the molecular weight, the greater the change in the developability of the relief printing original when stored in a high temperature environment. It is believed that this is because the smaller the molecular weight, the lower the entanglement of polyglycerol and polyglycerol derivatives, the higher the mobility of polyglycerol and polyglycerol derivatives, for example, the photosensitive resin composition is transformed into a more stable structure. On the other hand, when the molecular weight is larger, the viscosity of the compound is higher. When the photosensitive resin composition is prepared, there is a concern that the dispersibility of polyglycerol and polyglycerol derivatives in the photosensitive resin composition will deteriorate. The number average molecular weight of each of polyglycerol and polyglycerol derivatives can be selected from a range with any two values ​​selected from 300, 350, 400, 500, 600, 700, 750, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900 and 3000 as the lower limit and upper limit.

[0023] Specific examples of the polyglycerol derivatives of the component (d) include, but are not limited to, polyoxyethylene (4) polyglycerol ether, polyoxyethylene (6) polyglycerol ether, polyoxyethylene (13) polyglycerol ether, polyoxyethylene (20) polyglycerol ether, polyoxyethylene (30) polyglycerol ether, polyoxyethylene (40) polyglycerol ether, polyoxypropylene (4) polyglycerol ether, polyoxypropylene (9) polyglycerol ether, polyoxypropylene (14) polyglycerol ether, polyoxypropylene (18) polyglycerol ether, and polyoxypropylene (24) polyglycerol ether. The polyglycerol derivatives of the component (d) may be used not only as a single compound but also as a mixture of two or more compounds.

[0024] The proportion of component (d) in the photosensitive resin composition is preferably 3 to 15% by weight. When it is less than 3% by weight, the resin relief cannot maintain flexibility in a low temperature environment. This is because the contribution of component (d) to the plasticization of the resin relief is reduced. When it is less than 3% by weight, the developability of the relief printing original plate when stored in a high temperature environment increases. It is believed that this is due to the increased mobility of component (d) as described above. When the proportion is greater than 15% by weight, the dispersibility of component (d) in the photosensitive resin composition is significantly deteriorated. It is believed that this is due to the uneven distribution of component (d) and the polymer. When the dispersibility of component (d) in the photosensitive resin composition is deteriorated, the reproducibility of the developed resin relief when the relief printing original plate is stored in a high temperature environment may be deteriorated. The proportion of component (d) in the photosensitive resin composition is more preferably 4% by weight or more, further preferably 5% by weight or more, and further preferably 6% by weight or more. The proportion of component (d) in the photosensitive resin composition is more preferably 12% by weight or less, further preferably 10% by weight or less, and further preferably 8% by weight or less. The proportion of the component (d) in the photosensitive resin composition can be selected from a range with any two values ​​selected from 3.0 weight %, 3.5 weight %, 4.0 weight %, 4.5 weight %, 5.0 weight %, 5.5 weight %, 6.0 weight %, 6.5 weight %, 7.0 weight %, 7.5 weight %, 8.0 weight %, 8.5 weight %, 9.0 weight %, 9.5 weight %, 10 weight %, 11 weight %, 12 weight %, 13 weight %, 14 weight % and 15 weight % as the lower limit and upper limit.

[0025] Thermal polymerization inhibitors can improve the thermal stability of the photosensitive resin layer. Examples of thermal polymerization inhibitors include hydroquinones, benzoquinones, phenols, catechols, aromatic amine compounds, picric acids, phenothiazines, α-naphthoquinones, anthraquinones, nitro compounds, and sulfur compounds. The amount of thermal polymerization inhibitor used is preferably 0.001 to 2% by weight, more preferably 0.005 to 1% by weight, of the photosensitive resin composition. These compounds may be used in combination of not only a single compound but also a mixture of two or more compounds.

[0026] The thickness of the photosensitive resin layer is preferably 0.1 to 10 mm. If the thickness is less than 0.1 mm, the required relief depth for use as a printing plate may not be obtained, and if the thickness is greater than 10 mm, the weight of the printing plate becomes heavy, which may cause problems in practical operation.

[0027] The photosensitive resin composition may be formed into a photosensitive resin layer by any method other than the melt forming method, such as heat pressing, injection molding or melt extrusion, solution casting, or the like.

[0028] The photosensitive resin original plate as a relief printing original plate can be made by laminating a photosensitive resin layer formed into a sheet on a support via an adhesive layer. That is, the photosensitive resin original plate has a structure in which a support and a photosensitive resin layer are laminated. When a laminated body in which a sheet-like photosensitive resin layer is laminated on a support is supplied, a protective layer (covering film) is preferably further laminated on the photosensitive resin layer. At this time, the photosensitive resin original plate has a structure in which a support, a photosensitive resin layer and a protective layer are laminated in sequence. For the protective layer, it can be used on a plastic film, for example, a protective layer of a non-adhesive, transparent polymer compound dispersed or dissolved in a developer is coated with a thickness of 1 to 3 μm on a 125 μm thick polyester film. By arranging the protective layer having a thin polymer coating on the photosensitive resin layer, even if the surface adhesion of the photosensitive resin layer is strong, it is easy to peel off the protective layer during the subsequent exposure operation.

[0029] As a relief printing original plate, a CTP (Computer to Plate) plate without using a negative film can be produced by providing a heat-sensitive mask layer on the surface of a photosensitive resin layer. As the heat-sensitive mask layer, a known heat-sensitive mask layer can be used.

[0030] For the relief printing original plate, the photosensitive resin layer made of the photosensitive resin composition is overlapped with the negative film having the transparent image part in a close manner, and the exposure is performed by irradiating the above with active light. In this way, an original plate is made in which the exposed part that passes through the active light is insoluble. As active light, a light source such as a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp or a chemical lamp centered at a wavelength of 300 to 450 nm is usually used. On the other hand, in the case of a CTP plate, an IR laser is used to irradiate the thermal mask layer into an image pattern, and a mask (with the same function as the negative film) is formed on the photosensitive resin layer. After the image information is written into the thermal mask layer, the active light is irradiated on the entire surface of the photosensitive printing original plate through the mask to make an original plate in which the exposed part that passes through the active light is insoluble.

[0031] Next, an appropriate solvent, particularly neutral water in this specification, is used to dissolve and remove the uncured portion. Alternatively, the uncured portion may be dissolved and removed by a developing method such as a spray-type developing device or a brush-type developing device. After that, the printing plate from which the uncured portion has been dissolved and removed may be subjected to dehydration, drying, and post-exposure steps to obtain a final printing plate. Example

[0032] The following examples illustrate the effects of using the photosensitive resin composition of this specification, but the present invention is not limited to these. The parts in the examples refer to parts by weight. The numerical values ​​indicating the composition ratio in the table also refer to parts by weight.

[0033] (Preparation of polymer compound 1) 396 parts of ε-caprolactam, 469 parts of adipic acid, 341 parts of 1,4-bis(3-aminopropyl)piperazine, 199 parts of 1,3-bis(aminomethyl)cyclohexane, 34 parts of isophorone diamine, 5 parts of 50% hypophosphorous acid aqueous solution and 1000 parts of water were placed in an autoclave, nitrogen purged and sealed, and then slowly heated. Water was distilled off from the time when the internal pressure reached 0.4 MPa until the pressure could not be maintained. After about 2 hours, the pressure was restored to normal pressure and then reacted for 1 hour at normal pressure. The maximum polymerization reaction temperature was 255°C. Polyamide was obtained in this way. The composition of the polyamide was determined using H-NMR to confirm that there was no difference between the charged composition and the polymer composition.

[0034] (Preparation of polymer compound 2) Take 2 equivalents (672.8 parts) of hexamethylene diisocyanate to a flask equipped with a dropping funnel. After heating to 110°C under a nitrogen atmosphere, add 1 equivalent (1200.0 parts) of polyethylene glycol with a number average molecular weight of 600 using a dropping funnel under stirring. Continue stirring for 30 minutes after the addition. The amount of isocyanate in the resulting compound is half of the original amount, and the two terminal hydroxyl groups of the polyethylene glycol react with the isocyanate groups to obtain a PEG600-two-terminal HDI modified product having isocyanate groups at both ends. 219 parts of adipic acid, 400 parts of 1,4-cyclohexanedicarboxylic acid, 139 parts of 2-methylpentanediamine, 320 parts of 1,4-bis(3-aminopropyl)piperazine, 210 parts of isophoronediamine, 5 parts of 50% hypophosphorous acid aqueous solution and 1000 parts of water were placed in an autoclave, nitrogen purged and sealed, and then slowly heated. Water was distilled off from the time when the internal pressure reached 0.4 MPa until the pressure could not be maintained. After about 2 hours, the pressure was restored to normal pressure and then reacted for 1 hour under normal pressure. The maximum polymerization reaction temperature was 255°C. Polyamide was obtained in this way. Next, acrylonitrile was added to both ends of the obtained 1288 parts of polyamide and polypropylene glycol with a number average molecular weight of 400, and 120 parts of α,ω-diaminopolypropylene obtained by hydrogenation reduction were dissolved in 1690 parts of methanol. Then, 656 parts of PEG600-HDI modified product were slowly added under stirring, and the reaction was carried out for about 45 minutes. The solution was taken into a vessel coated with Teflon (registered trademark), and after evaporating and removing methanol, a high molecular compound obtained by reduced pressure drying was obtained. The composition of the polyamide was measured using H-NMR to confirm that there was no difference between the charging composition and the polymer composition.

[0035] Since polymer compounds 3, 4, and 5 were polymerized in the same manner, polymer compounds 1 to 5, which are polyamides and / or polyamide block copolymers, were obtained. The types and mixing ratios of the raw materials were changed as described in Table 1.

[0036] [Table 1] [wt%]

[0037] (Production of Support Body) 0.5 parts of dihydrothio-p-toluidine as an ultraviolet absorber was dissolved in 3.6 parts of dimethylaminoacetamide, and 100 parts of "Vylon30SS" (Toyobo Co., Ltd. product, solid content concentration 30%, molecular weight 20000-25000) as a polyester resin solution and 0.2 parts of "U-CAT SA102" (San-Apro Co., Ltd. product, DBU-octanoate composition) as a catalyst were dissolved in 0.7 parts of dioxane to prepare. Next, 10.2 parts of "Coronate L" (Nippon Polyurethane Industry Co., Ltd. product) as a multifunctional isocyanate was dissolved in 1.4 parts of ethyl acetate to prepare an adhesive composition solution. The solution was evenly coated on a 188 μm thick transparent polyester film support, and dried at 120°C for 1 minute using a hot air dryer to prepare a support having a 20 μm coating transparent adhesive layer.

[0038] (Production of Covering Film) A cover film in which a partially saponified Poval (48-80, manufactured by Kuraray Co., Ltd.) was coated on a 125 μm thick polyester film was prepared.

[0039] [Example 1] (Production of photosensitive resin master) 55.0 parts of polyamide resin as polymer compound 1 were added to a mixture of 62 parts of methanol and 10 parts of water, heated at 65°C to dissolve, 5.0 parts of diethylene glycol, 5.0 parts of lactic acid as a quaternizing agent, and 0.1 parts of p-hydroxyanisole were added, and further stirred for 30 minutes to dissolve, and the polyamide was ammonium salted to achieve water solubility. Then, 2.5 parts of glycidyl methacrylate (GMA), 1.0 parts of benzyl dimethyl ketal as a photopolymerization initiator, 12 parts of glycerol dimethacrylate (LIGHT ESTER G101P manufactured by Kyoeisha Chemical Co., Ltd.), 14.5 parts of 2-hydroxy-3-acryloxypropyl methacrylate (LIGHT ESTER G201P manufactured by Kyoeisha Chemical Co., Ltd.), and 5.0 parts of polyglycerol #500 were added, and stirred for 30 minutes to dissolve. Then, the temperature was slowly raised, methanol and water were distilled off, and concentration was performed until the temperature in the kettle reached 110°C. At this stage, a viscous photosensitive resin composition having fluidity was prepared. The photosensitive composition was cast on a 250 μm polyethylene terephthalate film as a support coated with 20 μm of an adhesive composition containing an ultraviolet absorber. A photosensitive resin original plate (relief printing original plate) of a sheet-like laminate with a total thickness of 1080 μm was formed using a laminator in such a manner that a cover film laminated with 2 μm of partially saponified Povar having a saponification degree of 79.5 mol% was in contact with the photosensitive resin composition cast on the 250 μm polyethylene terephthalate film.

[0040] [Examples 2 to 13, Comparative Examples 1 to 3] A photosensitive resin original plate (relief printing original plate) having a sheet-like laminate with a total thickness of 1080 μm was formed in the same manner as in Example 1. The evaluation results are shown in Table 2. Hereinafter, the photosensitive resin original plate is also referred to as a raw plate. R-PG: Polyglycerol manufactured by Sakamoto Pharmaceutical Industry Co., Ltd. Number average molecular weight 240 Polyglycerol #500: manufactured by Sakamoto Pharmaceutical Industry Co., Ltd. Polyglycerol number average molecular weight 500 SC-E350: POE (4) polyglycerol ether manufactured by Sakamoto Pharmaceutical Industry Co., Ltd. Number average molecular weight 350 SC-E1500: POE (30) polyglycerol ether manufactured by Sakamoto Pharmaceutical Industry Co., Ltd. Number average molecular weight 1500 SC-P750: manufactured by Sakamoto Pharmaceutical Industry Co., Ltd. POP (9) polyglycerol ether number average molecular weight 750 Epoxy ester 70PA: Propylene glycol diglycidyl ether acrylic acid adduct manufactured by Kyoeisha Chemical Co., Ltd.

[0041] [Table 2] [wt%] R-PG manufactured by Sakamoto Pharmaceutical Industry Co., Ltd. Polyglycerol number average weight 240 Polyglycerol #500 Manufactured by Sakamoto Pharmaceutical Industry Co., Ltd. Polyglycerol number average molecular weight 500 SC-E350 Sakamoto Pharmaceutical Industry Co., Ltd. POE (4) polyglycerol ether number average molecular weight 350 SC-E150 Sakamoto Pharmaceutical Industry Co., Ltd. POE (30) polyglycerol ether number average molecular weight 1500 SC-P750 Sakamoto Pharmaceutical Industry Co., Ltd. POP (9) polyglycerol ether number average molecular weight 750 70PA Kyoeisha Chemical Co., Ltd. Propylene glycol diglycidyl ether acrylic acid adduct

[0042] The reproducibility and developability of the raw plate when stored in a high temperature environment were evaluated, and the winding performance and surface layer of the resin relief plate (printing plate) when stored in a low temperature environment were evaluated.

[0043] [Table 3]

[0044] Here, the production process (plate making process) of the resin relief plate used for the evaluation is described. A printing evaluation negative film with an image containing 150 lines of dots 2% to 95%, a minimum independent dot diameter of 200 to 600 μm, a minimum independent line width of 60 to 150 μm, and a solid image (width 1 cm × length 5 cm) was used. The minimum exposure time for reproducing 150 lines - 2% was set as the optimal exposure time, and the illumination was adjusted to 3.4 mW / cm 2 The raw plate with the cover film peeled off is irradiated with ultraviolet light from a height of 5 cm above the photosensitive resin surface. Then, the brush washer ( The raw plate was developed with tap water at 25°C using a nylon brush (JW-A2-PD manufactured by Nippon Denshi Seiki Co., Ltd.) to obtain a relief image. After further hot air drying at 60°C for 10 minutes, ultraviolet irradiation was performed for 30 seconds using an ultra-high pressure mercury lamp to obtain a 15 cm square resin relief plate.

[0045] (1) Evaluation of reproducibility and developability when stored in a high temperature environment Evaluation was performed on the cases where the raw plate was stored for 60 days in an environment of a temperature of 22° C. and a humidity of 50% and in an environment of a high temperature of 50° C. and a humidity of 35% for 60 days. (Reproducibility evaluation) The reproducibility evaluation was performed by evaluating the reproducibility of the minimum independent dot and the minimum independent line in the developed resin relief plate when the exposure was performed at the optimum exposure time. The evaluation was performed by visual inspection using a 10-fold magnifying glass. ○: Both independent dots with a diameter of 200 μm and independent lines with a line width of 60 μm can be reproduced △: Only one of the independent dots with a diameter of 200 μm and the independent lines with a line width of 60 μm can be reproduced ×: Both independent dots with a diameter of 200 μm and independent lines with a line width of 60 μm cannot be reproduced (Developability Evaluation) The development property evaluation was performed by comparing the difference in development time of the raw plates stored in the above two environments in the respective plate-making steps. Here, the development time is the time required for the photosensitive resin composition that has not been cured by photoreaction to be completely washed away after irradiation with ultraviolet rays through the negative film. 0: The difference in development time between the two environments is less than 1 minute △: The difference in development time between the two environments is more than 1 minute but less than 2 minutes ×: The difference in development time between the two environments exceeds 2 minutes

[0046] (2) Evaluation of winding performance and surface layer during storage in low temperature environment The resin relief plate produced through the plate-making process was stored for 24 hours in an environment of temperature 22°C and humidity 50% and in a low-temperature environment of temperature 5°C and humidity 10%. After that, the produced printing plate was attached from the film side to a cylinder with a diameter of 9 cm with double-sided tape attached to the side, and the winding performance and surface layer were evaluated. In the surface layer evaluation, the naked eye was used to judge using a 10x magnifying glass. (Winding performance evaluation) 〇: Can be maintained for 30 minutes without peeling △: Partial shedding occurred within 30 minutes ×: Unable to wind (Surface state) 0: No cracks or damage on the printed plate ×: Cracks or defects occur on the printing plate

[0047] As shown in Table 3, it is known that the performances such as reproducibility, developability and winding property of any of the examples are each at a high level or an acceptable level. More specifically, it is described below.

[0048] In Examples 1 to 3, the content of polyglycerol in the photosensitive resin composition (hereinafter may also be referred to as the polyglycerol content) is different from each other. The polyglycerol content is 5% by weight in Example 1, 9% by weight in Example 2, and 13% by weight in Example 3. In Examples 1 to 3, the reproducibility, developability, and windability are all at a high level. In Examples 4 and 5, the photosensitive resin composition contains a polyglycerol derivative instead of polyglycerol. In Examples 4 and 5, the content of the polyglycerol derivative in the photosensitive resin composition (hereinafter may also be referred to as the polyglycerol derivative content) is the same as the polyglycerol content involved in Example 2, which is 9% by weight. In Example 4, the number average molecular weight of the polyglycerol derivative in the photosensitive resin composition is 350 less than the number average molecular weight of the polyglycerol in Example 2. In Example 5, the number average molecular weight of the polyglycerol derivative in the photosensitive resin composition is 1500 greater than the number average molecular weight of the polyglycerol in Example 2. In Examples 4 and 5, the reproducibility, developability, and windability are all at a high level. Example 6 is an example in which the content of the polyglycerol derivative in the photosensitive resin composition in Example 4 is reduced from 9 wt % to 5 wt %. Example 7 is an example in which the content of the polyglycerol derivative in the photosensitive resin composition in Example 5 is increased from 9 wt % to 13 wt %. In Examples 6 and 7, the reproducibility, developability, and winding properties were all at high levels.

[0049] In Examples 8 to 12, polymer compound 1 in the photosensitive resin composition is replaced by other polymer compounds. Polymer compound 2 is used in Example 8, polymer compound 3 is used in Example 9, polymer compound 4 is used in Examples 10 and 11, and polymer compound 5 is used in Example 12. In Examples 8 to 11, the reproducibility, developability, and winding properties are all at high levels. In Example 12, the reproducibility is at an acceptable level, and the developability and winding properties are at high levels. In Example 13, the polyglycerol contained in the photosensitive resin composition in Example 1 is replaced by a polyglycerol having a number average molecular weight of 500 with a polyglycerol having a number average molecular weight of 240. In Example 13, although the reproducibility is at a high level, the evaluations of developability and winding properties are at an acceptable level.

[0050] Comparative Example 1 is a comparative example in which polyglycerol is not contained in the photosensitive resin composition in Example 1. In Comparative Example 1, the reproducibility is at a high level, but the evaluations of developability and winding property are poor compared with the examples. Comparative Examples 2 and 3 are comparative examples in which the content of polyglycerol in Example 1 is 20% by weight as compared with that in Example 3. In Comparative Examples 2 and 3, although both developability and winding property are at a high level, the evaluation of reproducibility is poor compared with the examples.

Claims

1. A photosensitive resin composition for relief printing original plate, which is a photosensitive resin composition for relief printing original plate, The photosensitive resin composition contains (a) polyamide and / or polyamide block copolymer, (b) a crosslinking agent having one or more unsaturated groups, (c) a photopolymerization initiator, and (d) polyglycerol and / or a polyglycerol derivative. The polyglycerol derivative is obtained by addition polymerization of polyglycerol and ethylene oxide or propylene oxide. The content of (d) in the photosensitive resin composition is 3 to 15% by weight. 2 . The photosensitive resin composition for a relief printing original plate according to claim 1 , wherein the polyglycerol and the polyglycerol derivative (d) each have a number average molecular weight of 300 or more.

3. The photosensitive resin composition for relief printing original plate according to claim 1, wherein the photosensitive resin composition contains (d) a polyglycerol derivative, The polyglycerol derivative (d) is polyoxyethylene polyglycerol ether and / or polyoxypropylene polyglycerol ether having a number average molecular weight of 300 or more.

4. The photosensitive resin composition for a relief printing original plate according to claim 1, wherein the photosensitive resin composition contains 40 to 60% by weight of (a) polyamide and / or polyamide block copolymer, 20 to 50% by weight of (b) a cross-linking agent having one or more unsaturated groups, and 0.1 to 10% by weight of (c) a photopolymerization initiator; (a) polyamide and / or polyamide block copolymer contains more than 20% by weight of structural units composed of amide bonds in the form of blocks in the molecule. 5 . A relief printing original plate, comprising a support on which a photosensitive resin layer composed of the photosensitive resin composition for a relief printing original plate according to claim 1 is laminated.

6. A printing plate obtained by removing the uncured portion of the photosensitive resin layer from the relief printing original plate according to claim 5.

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