JP2007108477A - Photosensitive resin laminate and printing original plate for newspaper using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a flexographic printing original plate for newspaper printing which can be developed with an aqueous developer and has resistance to a water-based ink, such mechanical strength-ductility as to withstand high-speed printing, and good image reproducibility. <P>SOLUTION: A water-developable photosensitive resin laminate including a support and a photosensitive resin layer is used, wherein the support is a metal and the photosensitive resin layer has a mechanical strength-ductility property after photocuring of ≥80 kgf/cm<SP>2</SP>% and a water swelling rate of ≤8%. An adhesive layer containing an antihalation agent may be disposed between the support and the photosensitive resin layer, and the photosensitive resin layer may contain a hydrophobic polymer obtained from a water dispersion latex. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a photosensitive resin assembly laminate, and more particularly to a photosensitive resin printing original plate for flexographic printing which can be used for newspaper printing, which can be developed with an aqueous developer.

  Traditionally, newspaper printing has been performed by offset printing, but has had problems that are difficult to improve. First, because offset printing uses oil-based ink, the solvent is released into the atmosphere during drying, which is undesirable for the environment and the human body, and it is difficult to remove the ink solvent sufficiently after drying. However, there was a problem that when the printed characters were touched, the ink adhered. Furthermore, printing takes time for the offset plate, such as transferring ink to a subject via a blanket roll or using immersion water. In addition, the paper used at that time had a large loss.

  Therefore, in recent years, flexographic printing has begun to be performed instead of offset printing. In flexographic printing, since water-based ink can be used, adhesion of ink after drying can be prevented. Also, flexographic printing is a system in which ink is directly placed on a plate material and transferred directly from the plate material to a printing material without using a roll, so that there is an advantage that the printing start-up time and cost can be reduced.

  In flexographic printing, a solvent-developed flexographic plate that is developed with an organic solvent is generally used. However, in the solvent developing plate, since the odor of the solvent is generated, the working environment is bad, and the developing waste liquid cannot be poured into the waste water, and the labor and cost for disposal are added. In response to these backgrounds, recent heightened environmental awareness, and the tailwinds of environmental regulations, various water-developable flexographic plates have been proposed. For example, Patent Documents 1 to 5 below are known.

  However, since these water-developable flexographic plates are still under development, there is a drawback that the total performance, particularly the printing performance, is inferior to that of existing solvent-developed flexographic plates. For example, when halftone dots are printed using water-based ink, the print weight (dot gain) in the high line number highlight portion is particularly large, and high image quality cannot be obtained. This is considered to be due to the fact that the polarity of the plate is increased in order to impart water developability in addition to the deformation of the top of the relief against the printing pressure peculiar to flexographic printing.

As a water-developable flexographic plate, a flexographic plate material that can be developed with an aqueous developer and imparted resistance to water-based inks, a phase mainly composed of a hydrophobic polymer and a phase composed mainly of a hydrophilic polymer. There has been proposed a phase structure in which particles having a dispersed phase are used and a phase having a hydrophilic component and a hydrophobic component is a continuous phase (see, for example, Patent Document 6).
Japanese Patent Laid-Open No. 1-108542 Japanese Patent Laid-Open No. 2-175702 JP-A-1-3000024 JP-A-6-289610 European patent specification 584970 Japanese Patent Laid-Open No. 03-136052

When such a water-developable flexographic plate is used for newspaper printing, the length of the plate preparation time becomes a problem as compared with the offset printing plate. While the plate preparation time for a general water-developable flexographic plate is 1 hour, the actual work requires a significant time reduction of 30 minutes or less.
Therefore, a water-developable flexographic plate used for newspaper printing needs to use a relatively large amount of an elastomer or a water-soluble substance having a relatively low molecular weight in its composition to increase the developing speed. However, when the amount of water-soluble substances is increased, the water swelling rate of the plate increases, and a problem arises that the image becomes fat in general flexographic newspaper printing using water-based ink. Furthermore, as a serious problem, the material used for elastomers and other materials that do not have cross-linking reactivity increases, and when the molecular weight decreases, the mechanical strength and elongation characteristics of the plate deteriorate, and the printing durability during high-speed printing is remarkable. There was a problem of deteriorating.

  In view of the above problems, the present invention can be mounted on a conventional newspaper printing cylinder that can be developed with a water-based developer, has swelling resistance to water-based ink, and has mechanical strength that can withstand high-speed printing. It is an object of the present invention to obtain a photosensitive resin printing original plate.

In order to solve the above-mentioned problems, the present inventors have intensively studied, studied, and finally completed the present invention. That is, the present invention includes (1) having at least a support and a photosensitive resin layer, wherein the support is a metal, and the mechanical strength / elongation characteristic after photocuring of the photosensitive resin layer is 80 kgf / cm ^2. % Photosensitive resin laminate that can be developed with an aqueous developer. (2) The photosensitive resin laminate according to the above (1), wherein the water swelling ratio of the photosensitive resin layer is 8% or less. (3) The photosensitive resin laminate according to (1), wherein an adhesive layer is provided between the support and the photosensitive resin layer, and the adhesive layer contains an antihalation agent. (4) The photosensitive resin laminate according to (1), wherein the photosensitive resin layer contains a hydrophobic polymer obtained from an aqueous dispersion latex. (5) A newspaper printing original plate, wherein the photosensitive resin laminate according to any one of (1) to (4) is used.

  By using the photosensitive resin composition of the present invention, it is possible to develop with a water-based developer, and it is resistant to water-based inks and has mechanical strength and elongation that can withstand high-speed printing. Since a flexographic printing plate precursor for printing can be obtained, it contributes greatly to the industrial world.

Hereinafter, an embodiment of the present invention will be described.
In the present invention, a metal support is used so that it can be mounted on a printing cylinder of a newspaper printing press using an offset plate. Specific examples of the metal used for the support include aluminum, steel, titanium, nickel, zinc, lead, tin, and copper. Moreover, not only a pure metal but 2 or more types of alloys, plywood, and a metal oxide plate containing the said metal can also be used. In general, a support made of steel or aluminum having a relatively low cost and excellent plasticity is preferable. Furthermore, steel excellent in dimensional stability is particularly preferable.

  Moreover, in this invention, in order to adhere | attach a support body and the photosensitive resin layer, an adhesive layer can be provided between these two layers. The adhesive layer component is not particularly limited as long as it has sufficient adhesion that does not peel off during printing. As the component of the adhesive layer, for example, a binder polymer, an isocyanate compound, and other additives are preferable, and a binder polymer that is a main component is preferably a polymer having a functional group capable of reacting with an isocyanate group. Includes hydroxyl group, carboxyl group, amino group, mercapto group, etc., and as an oligomer or polymer having these in the main chain (including end groups) or side chain, specifically terephthalic acid, isophthalic acid, adipic acid Polyesters obtained from acid components such as sebacic acid and glycol components such as ethylene glycol, diethylene glycol, neopentyl glycol, 4,4′-di (2-hydroxyethoxyphenyl) 2,2′-propane, or caprolactone, Dimerized dry oil fatty acid (DA Immeric acid, etc.) and a reaction product of diamine or polyamine, polyamide such as methoxymethyl-6,6-nylon, methoxymethyl-6-nylon, nylon 6 / nylon 6,6 / nylon 6,10, Ken of polyvinyl acetate , Acryl-modified polyol (hydroxyalkyl (meth) acrylate, etc.), vinyl-based polymers such as saponified ethylene-vinyl acetate copolymer, bisphenol type, o-cresol / novolak type, tris (epoxypropyl) isocyanurate type, etc. Epoxy resins of these, or amine-modified polyols thereof, polyester polyols composed of adipic acid and triol and / or butylene glycol, and 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate or triisocyanate, etc. Oligomers or polymers having urethane bonds composed of various isocyanates, urea resins such as dimethylol urea condensates obtained from urea and formalin, formal resins such as polyvinyl formal and polyvinyl butyral, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, Cellulose derivatives such as ethyl cellulose, cellulose acetate, carboxymethyl cellulose, propyl cellulose, nitrocellulose, resole resin or novolak resin composed of phenol and formaldehyde, polyether 1,6-hexanediol such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol Polycarbonate diol obtained from ethylene carbo, with terminal Examples thereof include conjugated diolefin polymers such as liquid polybutadiene having a hydroxyl group or an amino group, phosphates, phosphonates, or phosphoramidate phosphorus-containing polyols.

  The isocyanate compound in the adhesive layer is a compound having two or more isocyanate groups, such as 2,4- or 2,6-tolylene diisocyanate, 2,4- or 2,6-cyclohexane diisocyanate-1- Methyl, naphthylene-1,5-diisocyanate, 1,4-tetramethylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, isopropylidenebis (cyclohexyl isocyanate), m- or p-xylylene diene Isocyanate, 1,3- or 1,4-cyclohexanedimethyl isocyanate, isophorone diisocyanate, lysine diisocyanate, bis (2-isocyanatoethyl) fumarate, 2,2,4-trimethylhexamethyl Range isocyanate, 3,3′-dimethoxy-4,4′-diphenyl diisocyanate, 2,4-tolylene dimer, tris (4-phenylisocyanate) thiophosphate, diphenyl ether 2,4,4′-triisocyanate, 2,4 ′ A trimer of tolylene diisocyanate, an oligoisocyanate obtained from a reaction product of tolylene diisocyanate and a polyfunctional alcohol (for example, trimethylolpropane-1-methyl-2-isocyano-4-carbamate), triphenylmethane p, p ', P "triisocyanate, dimer and trimer of hexamethylene diisocyanate (eg DESMODUR-N [trademark of BAYER), polymethylene polyphenyl isocyanate, 3-hydroxymethylpentane-2,4-diol and hexamethyl A reaction product of emissions diisocyanate, or an oxime of the isocyanates, and the like blocked isocyanates such as phenol.

In the present invention, the adhesive layer preferably contains an antihalation agent. This compound suppresses photocuring of a portion that should be a conventional unexposed portion by ultraviolet rays reflected from the support metal at the time of exposure, and enables a printed image having a greater relief depth and sharper. As an ideal UV absorber with antihalation effect, λmax is 360 nm, UV absorption edge is close to 400 nm, and it reacts with isocyanate in the adhesive layer to prevent extraction into the photosensitive resin layer over time A compound having a functional group (—NH ₂ , —OH, etc.) may be added as an antihalation agent.
In addition, it has a functional group that binds to an isocyanate compound for stability over time and a compound that binds to a base polymer, with Compound A having an absorption near 360 nm that is an antihalation agent or UV absorber. It is preferable that the compound B which has absorption in 380-400 nm is included. Examples of the functional group capable of reacting with isocyanate include a hydroxyl group, a carboxyl group, an amino group, a mercapto group, and the like, and an amino group and a hydroxyl group are preferable in consideration of reactivity and stability of effects. In addition, examples of the basic molecular skeleton of the UV absorber having UV absorbing ability bonded to these include benzene, naphthalene, anthracene, coumarin, quinoline, benzimidazole, benzothiazole, benzophenone, benzotriazole, and the like. It is not limited, You may have molecular structures other than these.

  Among these, specific examples of compound A having absorption at around 360 nm include dihydrothio-p-toluidine, 4-aminobenzophenone, 1-hydroxy-2-naphthoic acid ethylene glycol ester, 2-hydroxy-1-naphthoic acid. Examples thereof include ethylene glycol esters, and dihydrothio-p-toluidine and 4-aminobenzophenone are particularly preferable. In particular, the compound B having absorption at 380 to 400 nm specifically includes 2-aminobenzophenone, 3,4-diaminobenzophenone, 2-hydroxy-3-naphthoic acid hydrazide, 2-amino-3-naphthoic acid, 2 -Hydroxy-3-naphthoic acid ethylene glycol ester, 2-hydroxy-3-naphthoic acid propylene glycol ester, premulin, 9-anthracene methanol, 9-anthracene ethanol, 9-anthracene propanol, etc., in particular, 2-hydroxy-3 -Naphthoic acid ethylene glycol ester, 2-hydroxy-3-naphthoic acid propylene glycol ester, and 9-anthracenemethanol are preferable.

  Solvents for dissolving them include benzene organic solvents such as benzene and toluene, ketone organic solvents such as methyl ethyl ketone and acetone, ester solvents such as ethyl acetate, ethylene glycol solvents, dimethylaminoformaldehyde, dimethylaminoacetamide. Examples of the organic solvent include, but are not limited to.

  The photosensitive resin layer of the present invention can be developed with water. For example, the photosensitive resin layer contains (A) at least one elastomeric binder, (B) a photopolymerizable compound, and (C) a photopolymerization initiator. In addition to (D), a photosensitive resin composition containing a hydrophilic polymer or the like can be used.

What is important in the present invention is that the mechanical strength / elongation characteristic after photocuring of the photosensitive resin layer is 80 kgf / cm ² ·% or more in order to withstand high-speed printing during newspaper printing. Further, it is preferably 90 kgf / cm ² ·% or more, more preferably 100 kgf / cm ² ·% or more.
If the mechanical strength / elongation characteristic after photocuring of the photosensitive resin layer is less than 80 kgf / cm ² ·%, it is not preferable because independent points and fine lines are easily lost and a fine image cannot be printed.

In the present invention, in order to obtain a mechanical strength / elongation characteristic of 80 kgf / cm ² ·% or more, for example, a water-dispersible latex is used as the hydrophobic polymer contained in the photosensitive resin layer, and the number average molecular weight is 700. Examples thereof include the use of the above-mentioned photopolymerizable oligomers and linear alkyl methacrylates having 8 to 18 carbon atoms together with the photopolymerizable oligomers. In the present invention, particularly with the water-dispersible latex, the photopolymerizable oligomers and carbon are used. It is preferable to use a linear alkyl methacrylate of several 8-18.

The photosensitive resin of the present invention is resistant to swelling with respect to water-based ink used for flexographic newspaper printing, and has a water swelling ratio of 8% or less, preferably 7% or less, particularly for printing sharp images. 6% or less is desirable. For water-based developability, the water swelling rate is preferably 0.1% or more.
If the water swelling ratio is higher than 8%, the halftone dots are thickened or entangled due to swelling with water-based ink, and a sharp and delicate image cannot be reproduced.

  In the present invention, as a means for reducing the water swelling rate to 8% or less, for example, as the component (A) in the photosensitive resin layer, a hydrophobic polymer obtained from a water-dispersed latex can be used. A photosensitive resin laminate that can be developed with water and has a low water swelling rate can be obtained. Here, the water-dispersed latex is a polymer particle dispersed in water as a dispersoid, and additionally contains a surfactant.

Specific examples of the hydrophobic polymer include polybutadiene latex, natural rubber latex, styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, polychloroprene latex, polyisoprene latex, polyurethane latex, and methyl methacrylate-butadiene. Water-dispersed latex polymers such as copolymer latex, vinylpyridine polymer latex, butyl polymer latex, thiocol polymer latex, and acrylate polymer latex, and other components such as acrylic acid and methacrylic acid are copolymerized with these polymers And the resulting polymer. Among these, an aqueous dispersion latex polymer containing a butadiene skeleton or an isoprene skeleton in the molecular chain is preferably used from the viewpoint of hardness and rubber elasticity. Specifically, polybutadiene latex, styrene-butadiene copolymer latex, acrylonitrile-butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, and polyisoprene latex are preferable.
In the present invention, it is preferable to use two or more hydrophobic polymers obtained from the water-dispersed latex.

  The hydrophobic polymer obtained from the water-dispersed latex is preferably present in the form of fine particles in order to improve developability. Here, “exists on fine particles” means, for example, that observation of morphology and phase distribution is performed using a scanning probe microscope SPM, and polymers exist as independent particles without fusing with each other. The hydrophobic polymer fine particles preferably have a form dispersed in the component (B) or the component (C).

  The photopolymerizable compound which is the component (B) of the present invention is preferably a photopolymerizable oligomer, and the photopolymerizable oligomer has an ethylenically unsaturated group bonded to the terminal and / or side chain of the conjugated diene polymer. The number average molecular weight is 1000 or more and 10,000 or less. Specifically, it refers to a compound having the following structure in the molecular structure.

  The conjugated diene polymer constituting the conjugated diene ethylenic polymer is composed of a homopolymer of a conjugated diene unsaturated compound or a copolymer of a conjugated diene unsaturated compound and a monoethylenically unsaturated compound. Examples of such a conjugated diene unsaturated compound homopolymer or a copolymer of a conjugated diene unsaturated compound and a monoethylenically unsaturated compound include a butadiene polymer, an isoprene polymer, a chloroprene polymer, a styrene-chloroprene copolymer, Acrylonitrile-butadiene copolymer, acrylonitrile-isoprene copolymer, methyl methacrylate-isoprene copolymer, acrylonitrile-isoprene copolymer, methyl methacrylate-isoprene copolymer, methyl methacrylate-chloroprene copolymer, acrylic acid Methyl-butadiene copolymer, methyl acrylate-isoprene copolymer, methyl acrylate-chloroprene copolymer, methyl acrylate-chloroprene copolymer, acrylonitrile-butadiene-styrene copolymer, acrylonitrile copolymer Ropuren - styrene copolymer, and the like. Of these, a butadiene polymer, an isoprene polymer, and an acrylonitrile-butadiene copolymer are preferable from the viewpoint of rubber elasticity and photocurability, and a butadiene polymer and an isoprene polymer are particularly preferable.

  The method for introducing the terminal and / or side chain ethylenically unsaturated group of the conjugated diene polymer is not particularly limited. For example, (1) a hydroxyl group-terminated conjugated diene polymer obtained using hydrogen peroxide as a polymerization initiator. Monoethylenically unsaturated carboxylic acid such as (meth) acrylic acid or the like is ester-bonded to the terminal hydroxyl group by dehydration reaction, or monoethylenically unsaturated carboxylic acid such as methyl (meth) acrylate or ethyl (meth) acrylate (2) Conjugated diene heavy compounds obtained by copolymerizing an ethylenically unsaturated compound containing an unsaturated carboxylic acid (ester) at least partly with a conjugated diene compound. Examples include a method of reacting ethylenically unsaturated alcohol such as allyl alcohol and vinyl alcohol with the coalescence. .

  The amount of the ethylenically unsaturated group in the conjugated diene-based ethylenic polymer is preferably 0.005 to 2.0 meq / g, particularly preferably 0.01 to 2.0 meq in the polymer. When the amount is more than 2.0 m equivalent / g, the hardness becomes too high and it becomes difficult to obtain sufficient elasticity. When the amount is less than 0.005 m equivalent / g, the reactivity decreases and the image reproducibility tends to decrease.

  The content of these photopolymerizable oligomers is preferably 1 to 200 parts by weight with respect to 100 parts by weight of component (A). If the amount is 1 part by weight or less, the raw plate becomes hard and development with an aqueous developer cannot be performed. If the amount is 200 parts by weight or more, the raw plate becomes too soft and handling properties are deteriorated.

In the present invention, as described above, the mechanical strength / elongation characteristic after photocuring is required to be 80 kgf / cm ² ·% or more, that is, to increase the mechanical strength of the printing plate and improve the printing durability. In addition to the above, at least one of the photopolymerizable oligomers is preferably an alkyl methacrylate. In particular, the alkyl methacrylate preferably has 8 to 18 carbon atoms and is linear.

  Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl Alkyl (meth) acrylates such as (meth) acrylate, cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate, halogenated alkyl (meth) acrylates such as chloroethyl (meth) acrylate and chloropropyl (meth) acrylate, methoxyethyl Alkoxyalkyl (meth) acrylates such as (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, Examples thereof include phenoxyalkyl (meth) acrylates such as nylphenoxyethyl (meth) acrylate, and particularly preferably n-lauryl methacrylate, alkyl (C12-13) methacrylate, tridecyl methacrylate, alkyl (C12-15) methacrylate and the like. Is mentioned.

  The content of these alkyl methacrylates is preferably 1 to 50 parts by weight, particularly preferably 5 to 10 parts by weight with respect to 100 parts by weight of component (A). If it is less than 1 part by weight, the mechanical strength of the exposed plate is not sufficient, and if it exceeds 50 parts by weight, it bleeds out to the surface of the photosensitive resin composition layer, and the cover film becomes difficult to peel off.

  Moreover, the photopolymerization initiator is added to the photosensitive resin composition used in the present invention as the component (C). Any photopolymerization initiator can be used as long as it can polymerize a polymerizable carbon-carbon unsaturated group by light. Especially, what has the function to produce | generate a radical by self-decomposition or hydrogen abstraction by light absorption is used preferably. For example, benzoin alkyl ethers, benzophenones, anthraquinones, benzyls, acetophenones, diacetyls and the like. As a compounding quantity of a photoinitiator, the range of 0.1-50 weight part is preferable with respect to 100 weight part of (A) component. By setting it to 0.1 parts by weight or more, the image reproduction is good without reducing the starting efficiency. The amount of 50 parts by weight or less is preferable because the sensitivity is not too high and the exposure time can be easily controlled.

In the present invention, if necessary, a hydrophilic polymer may be blended as the component (D). Examples of the hydrophilic polymer include -COOH, -COOM (M is a monovalent, divalent or trivalent metal ion). Or a substituted or unsubstituted ammonium ion), a group having a hydrophilic group such as —OH, —NH ₂ , —SO ₃ H, or a phosphate ester group is preferable. Specifically, (meth) acrylic acid or a salt thereof is used. Polymer, copolymer of (meth) acrylic acid or its salt and alkyl (meth) acrylate, copolymer of (meth) acrylic acid or its salt and styrene, (meth) acrylic acid or its salt and vinyl acetate Copolymer, (meth) acrylic acid or its salt and acrylonitrile copolymer, polyvinyl alcohol, carboxymethylcellulose, polyacrylamide, hydroxy Ethylcellulose, polyethylene oxide, polyethyleneimine, polyurethane having -COOM group, polyureaurethane having -COOM group, include the polyamic acid and their salts or derivatives having a -COOM group. These may be used alone or in combination of two or more.

  The content of these hydrophilic polymers is preferably 0.1 to 50 parts by weight, particularly 0.1 to 30 parts by weight, based on 100 parts by weight of component (A). If it is less than 0.1 part by weight, the development time is delayed with an aqueous developer, and if it exceeds 50 parts by weight, the swelling with respect to water increases and the water-based ink resistance deteriorates.

  In the present invention, when the component (D) is blended, the component (A) and the component (A) preferably have a common skeleton structure. For example, examples of the common skeleton structure include an acrylonitrile-butadiene structure and a butadiene structure. Etc.

  A plasticizer can be further added to the photosensitive resin composition used in the present invention. The plasticizer is not particularly limited as long as it generally has a property of softening the plate material, but those having good compatibility with the components (A) and (D) are preferable. More preferred are polyene compounds which are liquid at room temperature and compounds having an ester bond. Examples of the polyene compound which is liquid at room temperature include liquid polybutadiene, polyisoprene, and maleated products and epoxidized products having their end groups or side chains modified. Examples of the compound having an ester bond include phthalic acid ester, phosphoric acid ester, sebacic acid ester, adipic acid ester, and polyester having a molecular weight of 1000 to 3000.

  When these plasticizer components are added, 0 to 100 parts by weight is preferable with respect to 100 parts by weight of component (A) from the viewpoint of obtaining sufficient strength as a solid plate before photocrosslinking.

  In order to increase the thermal stability of the photosensitive resin composition used in the present invention, a conventionally known polymerization inhibitor may be added. Preferable polymerization inhibitors include phenols, hydroquinones, catechols and the like. These compounding amounts are generally used in the range of 0.001 to 5% by weight with respect to the total photosensitive resin composition.

  As other components, dyes, pigments, viscosity modifiers, antifoaming agents, ultraviolet absorbers, fragrances, anti-aggregation agents, surfactants, and the like can be added.

  Depending on the composition, the photosensitive resin composition may become sticky, so that the contact with the transparent image carrier (negative film) superimposed thereon can be improved and the image carrier can be reused. Therefore, a flexible film layer that can be developed in an aqueous system may be provided on the surface.

  As a method for obtaining the photosensitive resin laminate of the present invention, each component of the photosensitive resin composition is mixed using an extruder, a kneader, or the like, and then a desired thickness is obtained by hot press molding, calendering, or extrusion molding. Layers can be formed. The support and the flexible film layer can be adhered to the photosensitive layer by roll lamination after sheet molding. A highly sensitive photosensitive layer can also be obtained by heating and pressing after lamination.

  Examples of the actinic ray source used for photocuring the photosensitive resin laminate of the present invention include a low pressure mercury lamp, a high pressure mercury lamp, an ultraviolet fluorescent lamp, a carbon arc lamp, a xenon lamp, a zirconium lamp, and sunlight. After the photosensitive resin composition of the present invention is irradiated with light through a transparent image carrier to form an image, a non-irradiated portion is removed (developed) using an aqueous developer to obtain a relief (printing plate).

  The aqueous developer referred to in the present invention is prepared by blending water with a nonionic or anionic surfactant, and if necessary, a pH adjusting agent, a cleaning accelerator and the like. Specific examples of the nonionic surfactant include polyoxyalkylene alkyl or alkenyl ether, polyoxyalkylene alkyl or alkenyl phenyl ether, polyoxyalkylene alkyl or alkenyl amine, polyoxyalkylene alkyl or alkenyl amide, ethylene oxide / propylene oxide There are block appendages. Specific examples of the anionic surfactant include linear alkylbenzene sulfonate having an alkyl having an average carbon number of 8 to 16, an α-olefin sulfonate having an average carbon number of 10 to 20, an alkyl group or an alkenyl group. A dialkyl sulfosuccinate having 4 to 10 carbon atoms, a sulfonate of a fatty acid lower alkyl ester, an alkyl sulfate having an average carbon number of 10 to 20, a linear or branched alkyl or alkenyl group having an average carbon number of 10 to 20 And alkyl ether sulfates having an average of 0.5 to 8 moles of ethylene oxide, saturated or unsaturated fatty acid salts having an average carbon number of 10 to 22 and the like.

  Examples of the PH adjuster include sodium borate, sodium carbonate, sodium silicate, sodium metasilicate, sodium succinate, sodium acetate, and the like. Sodium silicate is preferred because it is easily dissolved in water. Further, although there is a cleaning aid, the cleaning ability is enhanced by using it together with the surfactant and the pH adjusting agent. Specific examples include amines such as monoethanolamine, diethanolamine and triethanolamine, ammonium salts such as tetramethylammonium hydroxide, and paraffinic hydrocarbons. These are used by being added and mixed with water in an appropriate amount in the range of 0.1 to 50% by weight, preferably 1 to 10% by weight. After development, the plate is generally dried in an oven at about 60 ° C. for 15 to 120 minutes.

  Depending on the composition of the photosensitive resin composition, stickiness may remain on the plate surface even after drying. In that case, stickiness can be removed by a known surface treatment method. As the surface treatment method, an exposure treatment with an actinic ray having a wavelength of 300 nm or less is desirable.

Hereinafter, the present invention will be specifically described with reference to examples.
In addition, the characteristic value in an Example is a value obtained by the following measuring methods.
(1) Hardness: It is a value measured at 20 ° C. by a spring type hardness test (A type) method according to JIS-K6301.
(2) Rebound resilience: A steel ball with a diameter of 10 m / m (weight 4.16 g) is dropped from a height of 20 cm, the height bounce back (a) is read, and (a / 20) x 100% display did.
(3) Water swelling ratio: After photocuring the photosensitive resin composition heat-pressed to a thickness of 1 mm, the weight increase ratio (%) after being immersed in water at 20 ° C. for 1 hour or 24 hours was measured.
(4) Mechanical strength / elongation: After photocuring the photosensitive resin composition heat-pressed to a thickness of 1 mm, it was extracted with a mold and subjected to a tensile test of Tensilon (using a crosshead of 100 kg) at a test speed of 200 mm / min. It is a value obtained by multiplying the measured elongation and strength.

Example 1
As an elastomeric binder as component (A), hydrophobic polymer (α): acrylonitrile-butadiene latex (Nipol SX1503, nonvolatile content 42%, manufactured by Nippon Zeon Co., Ltd.) 20 parts by weight, hydrophobic polymer (β): butadiene Latex (Nipol LX111NF non-volatile content 55% Nippon Zeon Co., Ltd.) 36 parts by weight, (B) component, lauryl methacrylate (Light Ester L Kyoeisha Chemical Co., Ltd.) 4 parts by weight, trimethylolpropane trimethacrylate 4 parts by weight , 12 parts by weight of oligobutadiene acrylate (ABU-2S manufactured by Kyoeisha Chemical Co., Ltd.), 1 part by weight of photopolymerization initiator as component (C), hydrophilic polymer as component (D) (PFT-3 25% nonvolatile content) 12 parts by weight of Kyoeisha Chemical Co., Ltd., 6 parts by weight of conjugated diene oligomer (B2000, Nippon Petrochemical Co., Ltd.) as a plasticizer, Mix 0.1 parts by weight of hydroquinone monomethyl ether as a polymerization inhibitor in a container together with 5 parts by weight of toluene, then knead at 105 ° C. using a pressure kneader, and then remove toluene and water under reduced pressure. Thus, a photosensitive resin composition was obtained.

Next, the obtained photosensitive resin composition is sandwiched between a support having a polyester adhesive layer coated on a 170 μm-thick steel plate and a film in which an anti-adhesion layer (polyvinyl alcohol) is coated on a polyethylene terephthalate film ( Laminate the photosensitive resin with a thickness of 0.4 mm by pressurizing with a heat press machine at 105 ° C. and a pressure of 100 kg / cm ² for 1 minute so that the adhesive layer and the anti-adhesion layer are in contact with the photosensitive resin composition. A body (photosensitive resin original plate) was prepared. The obtained original plate was peeled off and applied to an inspection negative including a halftone dot line of 1% to 95%, a minimum independent point diameter of 100 μm, a minimum convex character of 1 point, a minimum extracted character of 1 point, a solid image, and a step guide at 365 nm. Back exposure and front exposure were performed using an illuminance of 17.5 W / m ² (Anderson & Vreland lamp FR20T12-BL-9-BP), the negative film was removed, and 40 ° C. containing 4% by weight of sodium alkylnaphthalenesulfonate. Developed with neutral water for 8 minutes and dried at 60 ° C. for 10 minutes.

  The obtained printing plate has a relief depth of 0.30 mm, and when printed with water-based ink, halftone dot lines of 1% to 95%, minimum independent point diameter of 100 μm, minimum independent line width of 30 μm, minimum punched line width of 100 μm The minimum convex character 1 point and the minimum extracted character 1 point could be reproduced.

  The obtained printing plate had a Shore A hardness of 60, a rebound resilience of 60%, and a water swelling ratio after 24 hours of 5.0%.

The mechanical strength and elongation properties of the obtained printing plate were 165 kgf / cm ² ·%, and a good printed product was obtained without damage to the plate even after printing 100,000 copies.

Comparative Example 1
As an elastomeric binder as component (A), 75 parts by weight of an acrylate / butadiene copolymer, 10 parts by weight of isoprene / styrene copolymer, as component (B), 6 parts by weight of lauryl acrylate, trimethylolpropane trimethacrylate 5 parts by weight, 1 part by weight of a photopolymerization initiator of component (C), 3 parts by weight of phenoxypolyethylene glycol as a surfactant, and BHT (2,6-di-tert-butyl-4-methylphenol) as a polymerization inhibitor 5 parts by weight was mixed in a container, then kneaded at 105 ° C. using a pressure kneader, and then toluene and water were removed under reduced pressure to obtain a photosensitive resin composition, which was the same as in Example 1. Thus, a photosensitive resin original plate and a printing plate were prepared.

The resulting printing plate had a Shore A hardness of 68 °, a rebound resilience of 30%, and a water swell ratio of 24% after 24 hours, but the mechanical strength and elongation properties were 30 kgf / cm ² ·%, When printing, independent points were skipped and thin lines were missing.

  As described above, the photosensitive resin assembly laminate of the present invention having such a configuration can be used as a flexographic printing original plate for newspapers that can be developed with an aqueous developer, has resistance to aqueous ink, and has good image reproducibility.

Claims (5)

A photosensitive resin laminate having at least a support and a photosensitive resin layer, wherein the support is made of metal, and the mechanical strength and elongation properties of the photosensitive resin layer after photocuring are 80 kgf / cm ² ·%. A photosensitive resin laminate that can be developed with an aqueous developer.   The photosensitive resin laminate according to claim 1, wherein the water swelling ratio of the photosensitive resin layer is 8% or less.   The photosensitive resin laminate according to claim 1, wherein an adhesive layer is provided between the support and the photosensitive resin layer, and the adhesive layer contains an antihalation agent.   The photosensitive resin laminated body of Claim 1 in which the photosensitive resin layer contains the hydrophobic polymer obtained from water dispersion | distribution latex.   A newspaper printing original plate, wherein the photosensitive resin laminate according to claim 1 is used.