阅读说明：本技术 连结印刷版 (Binding printing plate ) 是由 天野正典 于 2019-03-13 设计创作，主要内容包括：为了提供一种连结印刷版,使多个具有挠性的印刷版利用1张粘接于这些印刷版1的背面1a的单面粘合片2和将相邻的印刷版1的侧面1b彼此粘接的粘接剂固化部3进行了连结,该粘接剂固化部3具有下述(A)～(C)的物性。(A)伸长率为260％以上。(B)自单面粘合片2剥离的180°剥离强度为4N/10mm以上。(C)在23℃的N-甲基-2-吡咯烷酮中浸渍24小时时的溶胀率为30质量％以下,所述连结印刷版是将多个印刷版连结而得的,连结部分(粘接剂固化部)的耐断裂性得以提高。(In order to provide a connection printing plate, a plurality of flexible printing plates are connected by 1 single-sided adhesive sheet 2 adhered to the back surface 1a of the printing plates 1 and an adhesive curing part 3 for adhering the side surfaces 1b of the adjacent printing plates 1, wherein the adhesive curing part 3 has the following physical properties (A) to (C). (A) The elongation is 260% or more. (B) The 180 DEG peel strength of the single-sided pressure-sensitive adhesive sheet 2 is 4N/10mm or more. (C) The swelling ratio when the ink is immersed in N-methyl-2-pyrrolidone at 23 ℃ for 24 hours is 30 mass% or less, and the linked printing plate is obtained by linking a plurality of printing plates, and the fracture resistance of the linked part (cured part of the adhesive) is improved.)

1. A connection printing plate is characterized by comprising:

a plurality of printing plates having a flexible printing surface formed on one surface thereof;

a single-sided adhesive sheet that is adhered to a surface of an adjacent printing plate opposite to the printing surface to connect the adjacent printing plates; and

a flexible adhesive-cured portion provided between the facing side surfaces and the side surfaces of the adjacent printing plates to bond the side surfaces to each other,

the linked printing plate is detachably mounted to the outer peripheral surface of the plate cylinder,

the cured adhesive part has the following physical properties (A) to (C):

(A) the elongation is more than 260%;

(B) a 180 DEG peel strength from a single-sided adhesive sheet of 4N/10mm or more;

(C) the swelling ratio of the resin composition when the resin composition is immersed in N-methyl-2-pyrrolidone at 23 ℃ for 24 hours is 30 mass% or less.

Technical Field

The present invention relates to a joined printing plate obtained by joining a plurality of printing plates.

Background

In recent years, an alignment film or an insulating film is often formed on the surface of a TFT substrate or a color filter substrate used in a liquid crystal television by a flexographic printing method. Since liquid crystal televisions are becoming larger year by year, printing plates used in flexographic printing methods are also becoming larger. In this case, the printing plate needs to have a size of, for example, about 2500mm × 3000 mm. However, since printing plates of such a size cannot be manufactured by existing facilities, it is considered that the existing facilities themselves are enlarged. However, this operation results in a significant increase in cost.

Therefore, a joint printing plate has been proposed which is large in size by joining a plurality of printing plates of a size that can be manufactured by conventional equipment (see, for example, patent document 1). The bonded printing plate is obtained by abutting the side surfaces of printing plates to be bonded with a gap therebetween, injecting an adhesive into the gap, and curing the adhesive. Generally, a photocurable resin is used as a material for forming the printing plate, and the same material (photocurable resin) as that for forming the printing plate is used as the bonding adhesive.

Here, the flexographic printing method performs the following operations: in a state where a printing plate is attached to the outer peripheral surface of a cylindrical plate cylinder, ink as a material for forming the alignment film, the insulating film, or the like is supplied to the printing plate while the plate cylinder is rotated, and the ink is transferred to a printing object such as a glass substrate. Therefore, the printing plate has a flexibility of a degree that the printing plate can be detachably attached to the outer peripheral surface of the plate cylinder. In addition, the connecting portion (cured adhesive portion) of the connected printing plate also has flexibility so as to be detachably attached to the outer peripheral surface of the plate cylinder.

Disclosure of Invention

Problems to be solved by the invention

However, if the above-described connection printing plate is used for a long time, the connection portion (adhesive cured portion) of the connection printing plate may be broken. When the connecting portion (adhesive cured portion) is broken, the connecting portion is replaced with a new connecting printing plate. Therefore, if the frequency of occurrence of the breakage is high, the frequency of interruption of the printing operation is also high, and therefore, the operation efficiency is deteriorated and the replacement cost of the connected printing plate is also high.

Therefore, the present inventors have conducted detailed investigations on the cause of the fracture, and as a result, have found that: in the flexographic printing method, the solvent (N-methyl-2-pyrrolidone) used for the ink deteriorates the joint portion of the joint printing plate. In addition, it is known that: since the connection printing plate is in contact with the printing object while being bent along the outer peripheral surface of the plate cylinder, a tensile load or vibration is applied to the connection printing plate due to friction with the printing object. And found that: the stress caused by the tensile load and the vibration concentrates on a connecting portion parallel to the rotation axis of the plate cylinder, and the fracture occurs.

The present invention has been made in view of such circumstances, and provides a joined printing plate obtained by joining a plurality of printing plates, which has improved fracture resistance at the joined portion (cured adhesive portion).

Means for solving the problems

In order to achieve the above object, a connection printing plate of the present invention has the following configuration: it is provided with: a plurality of printing plates having a flexible printing surface formed on one surface thereof; a single-sided adhesive sheet that is adhered to a surface of an adjacent printing plate opposite to the printing surface to connect the adjacent printing plates; and a flexible adhesive curing section provided between the side surfaces and the opposite side surfaces of the adjacent printing plates to bond the side surfaces to each other, wherein the connected printing plate is detachably attached to the outer peripheral surface of the plate cylinder, and the adhesive curing section has the following physical properties (a) to (C).

(A) The elongation is 260% or more.

(B) The 180 DEG peel strength of the adhesive sheet peeled from the single-sided adhesive sheet is 4N/10mm or more.

(C) The swelling ratio of the resin composition when the resin composition is immersed in N-methyl-2-pyrrolidone at 23 ℃ for 24 hours is 30 mass% or less.

The present inventors have made extensive studies with attention paid to the physical properties of the adhesive-cured portion in order to improve the fracture resistance of the connecting portion (adhesive-cured portion) connecting printing plates. In the course of this study, it was thought that the hardness of the adhesive cured portion was reduced. As a result, although the fracture resistance of the cured adhesive portion is improved, the positions of the adjacent printing plates may be shifted relative to each other, and the ink may not be transferred to an appropriate position of the printing object. Accordingly, the present inventors have conducted extensive studies on physical properties other than the hardness of the cured adhesive part. As a result, they found that: if the adhesive cured portion has the physical properties (a) to (C), the fracture resistance of the adhesive cured portion can be improved, and printing can be performed appropriately.

ADVANTAGEOUS EFFECTS OF INVENTION

In the present invention, since the cured adhesive portion for bonding adjacent printing plates has the physical properties (a) to (C), the cured adhesive portion can be improved in fracture resistance and can be suitably printed. As a result, the frequency of replacing the linked printing plate is reduced, and the printing efficiency can be improved. In addition, the replacement cost of the linked printing plate can be prevented from increasing.

Drawings

Fig. 1 schematically shows an embodiment of a bonded printing plate of the present invention, (a) is a plan view thereof, and (b) is an enlarged view of an X-X section of a bonded portion of a circular portion Y in (a).

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Fig. 1 (a) is a plan view schematically showing one embodiment of the joint printing plate of the present invention, and fig. 1 (b) is an enlarged view of the X-X section of the joint portion in the circular portion Y in fig. 1 (a). As shown in fig. 1 (a) and (b), the connection printing plate according to the present embodiment is formed by connecting 2 flexible printing plates 1. This connection is performed by 1 single-sided adhesive sheet 2 adhered to the back surface (surface opposite to the printing surface) 1a of the printing plate 1 and an adhesive cured portion 3 adhering the side surfaces 1b of the printing plate 1 to each other. The cured adhesive part 3 is also bonded to the adhesive surface of the single-sided adhesive sheet 2. The width W of the cured adhesive part 3 is usually set within the range of 0.5 to 4 mm. In fig. 1 (a), reference numeral 11 denotes a printing convex portion formed in the central region of the printing surface (front surface) of the printing plate 1.

In the production of the above-mentioned connection printing plate, first, 1 sheet of the above-mentioned single-sided adhesive sheet 2 having an area substantially equal to the area of the connection printing plate to be produced is prepared. Then, the back surface 1a of 2 printing plates 1 to be joined is bonded to the adhesive surface of the single-sided adhesive sheet 2. At this time, the side surfaces 1b of the 2 printing plates 1 are opposed to each other with a gap therebetween. Then, after the adhesive is injected into the gap, the adhesive is cured. Thereby, the adhesive forms an adhesive cured portion 3, and the adhesive cured portion 3 adheres to the adhesive surface of the one-sided adhesive sheet 2 and adheres the facing side surfaces 1b of the 2 printing plates 1 to each other. In this manner, the 2 printing plates 1 are joined by the single-sided adhesive sheet 2 and the adhesive curing section 3, and the joined printing plate can be produced.

The cured adhesive portion 3 of the joined printing plate has the following properties (a) to (C). This is a feature of the present invention. With this feature, the fracture resistance of the adhesive cured portion 3 can be improved, and printing using the connection printing plate can be performed appropriately.

(A) The elongation is 260% or more.

(B) The 180 DEG peel strength of the single-sided pressure-sensitive adhesive sheet 2 is 4N/10mm or more.

(C) The swelling ratio of the resulting product when immersed in N-methyl-2-pyrrolidone (hereinafter referred to as "NMP") at 23 ℃ for 24 hours is 30% by mass or less.

In other words, by providing the cured adhesive part 3 with the physical property (elongation of 260% or more) of the above (a), the flexibility of the cured adhesive part 3 is increased, and the load and vibration applied to the above-described joined printing plate when used in the flexographic printing method can be absorbed and reduced. The above elongation is a value measured according to JIS7311-1995 and calculated by the following formula.

Elongation (%) { (L)₁-L₀)/L₀}×100

In the above formula, L₀Distance of the marked line, L₁The distance between the standard lines when cutting is used.

The cured adhesive part 3 has the physical properties (180 ° peel strength from the single-sided adhesive sheet 2 of 4N/10mm or more) of the above (B), and thus the cured adhesive part 3 is firmly bonded to the adhesive surface of the single-sided adhesive sheet 2. In addition, the adhesive curing section 3 bonds the adjacent 2 printing plates 1 together, and the relative positional deviation of the adjacent 2 printing plates 1 can be reduced.

Further, by providing the cured adhesive part 3 with the physical properties of (C) described above (the swelling ratio when immersed in NMP at 23 ℃ for 24 hours is 30 mass% or less), the cured adhesive part is less likely to swell with respect to the solvent (NMP) used for the material for forming an alignment film or the like to be printed. Therefore, the adhesive cured portion 3 can be made less likely to be deteriorated by the solvent. The swelling ratio is a value calculated by the following formula.

Swelling ratio (%) { (W)₂-W₁)/W₁}×100

In the above formula, W₁The mass of the test piece before immersion, W₂The mass of the test piece after immersion.

More specifically, the printing plate 1 is a printing plate used in a flexographic printing method, and has a flexibility of a degree that it can be detachably attached to the outer peripheral surface of a cylindrical plate cylinder. Examples of the material for forming the printing plate 1 include resins such as photocurable resins.

The single-sided adhesive sheet 2 is composed of a sheet-like base material and an adhesive layer formed on one side of the base material. The surface on which the adhesive layer is formed is the adhesive surface. The substrate is made of synthetic resin such as PET (polyethylene terephthalate) and has a thickness of 0.1-0.5 mm. The adhesive layer is formed of, for example, an acrylic resin, and is applied to one surface of the substrate by a coater or the like to have a thickness of 5 to 50 μm.

The adhesive cured portion 3 has the physical properties (a) to (C) described above. The connecting printing plate has a flexibility of a degree that the connecting printing plate can be detachably attached to the outer peripheral surface of a cylindrical plate cylinder used in a flexographic printing method, in addition to the fracture resistance. Examples of the material (adhesive) for forming the adhesive cured portion 3 include a photocurable resin composition containing the following components (a) to (c).

(a) An unsaturated polyurethane prepolymer comprising a hydrogenated polybutadiene structure.

(b) (meth) acrylate ester monomer.

(c) A photopolymerization initiator.

In the present invention, "(meth) acrylate" means one or both of acrylate and methacrylate.

[ (a) unsaturated polyurethane prepolymer containing hydrogenated polybutadiene Structure ]

The unsaturated polyurethane prepolymer having a hydrogenated polybutadiene structure (a) can be produced by a known production method. For example, it can be obtained by reacting hydrogenated polybutadiene (a1) having a hydroxyl group, a polyisocyanate (a2) having 2 or more isocyanate groups, and a compound (a3) having both a functional group containing an active hydrogen and an ethylenically unsaturated bond in the molecule.

The proportions of the hydrogenated polybutadiene (a1), the polyisocyanate (a2) and the compound (a3) are preferably set as follows, for example. In other words, the prepolymer precursor having an NCO group at the polymer end is synthesized by reacting the polyisocyanate (a2) at a molar ratio (NCO group/OH group) of the isocyanate group (NCO group) to the hydroxyl group (OH group) of the hydrogenated polybutadiene (a1) of 1.0 to 2.0. The reaction is preferably carried out so that the molar ratio (NCO group/OH group) of the isocyanate group (NCO group) at the end of the polymer chain of the prepolymer precursor to the hydroxyl group (OH group) of the compound (a3) is in the range of 0.8 to 1.0, and more preferably so that the hydroxyl group (OH group) and the isocyanate group (NCO group) are in equal amounts. When the ratio of the hydrogenated polybutadiene (a1) to the polyisocyanate (a2) to the compound (a3) is within the above range, the ethylenically unsaturated bond is sufficiently introduced, and the physical properties such as the adhesiveness and the strength of the adhesive cured portion 3 can be improved, or the reduction in storage stability due to the excess isocyanate group remaining can be suppressed.

The hydrogenated polybutadiene (a1) is preferably a hydrogenated polybutadiene having a1, 2-polybutadiene structure of 80 mass% or more, from the viewpoint of improving the adhesiveness of the cured adhesive part 3.

The polyisocyanate (a2) may be a diisocyanate, triisocyanate or other polyisocyanate having 2 or more isocyanate groups. Examples of the diisocyanate include 2, 6-tolylene diisocyanate, 2, 4-tolylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, p-hydrogenated xylylene diisocyanate, m-hydrogenated xylylene diisocyanate, isophorone diisocyanate, 1, 6-hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, 4' -diphenylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, and the like. Examples of the triisocyanate include: biuret products and isocyanurate products of toluene diisocyanate, biuret products and isocyanurate products of isophorone diisocyanate, and biuret products and isocyanurate products of 1, 6-hexamethylene diisocyanate. Among them, from the viewpoint of easy production of the unsaturated polyurethane prepolymer (a), diisocyanate is preferable, and isophorone diisocyanate and 1, 6-hexamethylene diisocyanate in the form of non-yellow modification are more preferable. These may be used alone or in combination of 2 or more.

The compound (a3) may be a compound having a functional group containing an active hydrogen and an ethylenically unsaturated bond in the molecule, and is preferably a compound having a hydroxyl group and an ethylenically unsaturated bond in the molecule. Examples of such compounds include: hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycerol mono-or di (meth) acrylate, and the like. These may be used alone or in combination of 2 or more.

Further, the number average molecular weight of the unsaturated polyurethane prepolymer (a) obtained by reacting the hydrogenated polybutadiene (a1), the polyisocyanate (a2) and the compound (a3) is preferably 10000 to 50000. This is because if the number average molecular weight is too small, the hardness of the cured adhesive part 3 tends to be high (flexibility is poor), whereas if it is too large, compatibility with monomers tends to be poor, and it is difficult to obtain a uniform adhesive. The number average molecular weight of the unsaturated polyurethane prepolymer (a) is more preferably in the range of 15000 to 30000 from the viewpoint of more preferable adhesiveness, flexibility and compatibility. The number average molecular weight referred to herein is a polystyrene-equivalent average molecular weight obtained by Gel Permeation Chromatography (GPC).

[ (b) (meth) acrylate monomer ]

Examples of the (meth) acrylate ester monomer of the above (b) include monomers having a linear or branched alkyl group, such as 2-ethylhexyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, n-octyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-octadecyl (meth) acrylate; cycloalkyl group-containing monomers such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, mono-, di-or trialkylcyclohexyl (meth) acrylate, cyclohexyloxyethyl (meth) acrylate, cycloheptyl (meth) acrylate, and the like; cycloalkenyl group-containing monomers such as cyclohexenyl (meth) acrylate, mono-, di-or trialkylcyclohexenyl (meth) acrylate, cycloheptenyl (meth) acrylate, cyclohexenyloxyethyl (meth) acrylate, and cycloheptenyloxyethyl (meth) acrylate; monomers having a bicycloalkyl group such as [ (1S,4S) -1,7, 7-trimethyl-6-bicyclo [2.2.1] heptanyl ] (meth) acrylate; monomers having a bicycloalkenyl group such as [ (1S,4S) -1,7, 7-trimethyl-6-bicyclo [2.2.1] heptenyl ] (meth) acrylate; tricycloalkyl group-containing monomers such as tricyclo [5.2.1.0(2,6) ] decan-8-yl (meth) acrylate, (ethoxy) tricyclo [5.2.1.0(2,6) ] decan-8-yl (meth) acrylate, 2-methyltricyclo [3.3.1.1(3,7) ] decan-2-yl (meth) acrylate, 2-ethyltricyclo [3.3.1.1(3,7) ] decan-2-yl (meth) acrylate, and the like; monomers having a tricycloalkenyl group such as 2- (3a,4,5,6,7,7 a-hexahydro-4, 7-methano-1H-inden-6-yl) acrylate, and 2- [ (3a,4,5,6,7,7 a-hexahydro-4, 7-methano-1H-inden-6-yl) oxy ] ethyl (meth) acrylate; and (b) at least 1 or more of a hydroxyalkyl (meth) acrylate having 2 to 4 carbon atoms in the alkyl group, a polyalkylene glycol (meth) acrylate having 2 to 4 carbon atoms in the alkylene glycol and 1 to 10 repeating units in the alkylene glycol, and an alkoxy polyalkylene glycol (meth) acrylate having 2 to 4 carbon atoms in the alkoxy group, 2 to 4 carbon atoms in the alkylene glycol and 1 to 10 repeating units in the alkylene glycol. These may be used alone or in combination of 2 or more.

The content of the (meth) acrylate monomer (b) is usually 5 to 400% by mass, preferably 20 to 300% by mass, and more preferably 40 to 230% by mass, based on the mass of the unsaturated polyurethane prepolymer (a) having a hydrogenated polybutadiene structure.

[ (c) photopolymerization initiator ]

Examples of the photopolymerization initiator (c) include: acetophenones such as diethoxyacetophenone and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoins such as benzoin, α -methylbenzoin, and α -phenylbenzoin; benzophenones such as benzophenone, benzoylbenzoic acid, and methyl benzoylbenzoate; α aminoketones such as 2-methyl-1- [4- (methylthio) phenyl ] -2- (4-morpholinyl) -1-propanone; xanthones such as xanthone and thioxanthone; anthraquinones such as anthraquinone and 2-methylanthraquinone; { 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] propan-1-one } and the like. These may be used alone or in combination of 2 or more.

The content of the photopolymerization initiator (c) is usually 0.2 to 20% by mass, preferably 0.3 to 15% by mass, and more preferably 0.5 to 10% by mass, based on the total mass of the unsaturated polyurethane prepolymer (a) having a hydrogenated polybutadiene structure and the (meth) acrylate monomer (b) (when the ethylenically unsaturated compound (f) described later is contained, the total mass further contains the ethylenically unsaturated compound (f)).

In addition to the components (a) to (c), other components may be used as required. Examples of other components include: the silane coupling agent (d), the flexibility imparting agent (e), the ethylenically unsaturated compound (f) other than the component (b), and various additives (g) described below.

[ (d) silane coupling agent ]

Examples of the silane coupling agent (d) include: alkylalkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, gamma-methacryloxypropyltrimethoxysilane, gamma-methacryloxypropyltriethoxysilane, gamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane, gamma-chloropropyltrimethoxysilane, gamma-mercaptopropyltrimethoxysilane, n-propyltriethoxysilane, and n-octyltriethoxysilane; polyether-modified alkoxysilanes, and the like. Among these, nonionic silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, γ -methacryloxypropyltrimethoxysilane, γ -methacryloxypropyltriethoxysilane, γ -glycidoxypropyltrimethoxysilane, and polyether-modified alkoxysilanes are preferable from the viewpoint of affinity for the respective components (a) to (c). These may be used alone or in combination of 2 or more. The proportion of the silane coupling agent (d) is preferably 5% by mass or less based on the total mass of the components (a) to (c).

[ (e) softness imparting agent ]

Examples of the flexibility imparting agent (e) include: terpene-based resins such as polybutadiene, hydrogenated polybutadiene, terpene resins, hydrocarbon-modified terpene resins, and hydrides thereof; terpene-phenol resins such as terpene-phenol resins and hydrogenated products of the terpene-phenol resins; petroleum resins such as aliphatic petroleum resins, alicyclic petroleum resins, aromatic petroleum resins, copolymer petroleum resins, dicyclopentadiene petroleum resins, pure monomer petroleum resins, and hydrogenated products thereof; rosin-based resins such as gum rosin, tall rosin, wood rosin, disproportionated rosin, polymerized rosin, glycerol esters and pentaerythritol esters of these rosins, and hydrides thereof; styrene resin, coumarone-indene resin, alkylphenol resin, xylene resin, dammar resin (dammar), copal (copal), shellac (shellac), and the like. These may be used alone or in combination of 2 or more. Among these, polybutadiene is preferable from the viewpoint of improving the affinity and flexibility with each of the components (a) to (c). The ratio of the flexibility imparting agent (e) is preferably 100% by mass or less with respect to the total mass of the components (a) to (c).

[ (f) olefinically unsaturated Compounds ]

Examples of the ethylenically unsaturated compound (f) include: di (meth) acrylates such as linear or branched alkyl esters having 1 to 7 carbon atoms of (meth) acrylic acid, haloalkyl (meth) acrylates, aminoalkyl (meth) acrylates, tetrahydrofurfuryl (meth) acrylates, allyl (meth) acrylates, glycidyl (meth) acrylates, benzyl (meth) acrylates, phenoxy (meth) acrylates, N-substituted or N, N '-substituted (meth) acrylamides, diacetone (meth) acrylamide, N' -alkylenebis (meth) acrylamides, alkyleneglycol di (meth) acrylates, polyalkylene glycol di (meth) acrylates, polyalkylene oxide-modified bisphenol a di (meth) acrylates, and the like; polyfunctional (meth) acrylates such as trimethylolpropane tri (meth) acrylate, trimethylolpropane alkoxy tri (meth) acrylate, glycerol alkoxy tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate. These may be used alone or in combination of 2 or more. The proportion of the ethylenically unsaturated compound (f) is preferably 5% by mass or less based on the total mass of the components (a) to (c).

[ (g) additives ]

Examples of the additives (g) include thermal polymerization inhibitors, antioxidants, flame retardants, surfactants, antistatic agents, colorants, plasticizers, surface lubricants, leveling agents, and softeners. The proportion of the additive (g) is preferably 5% by mass or less based on the total mass of the components (a) to (c).

[ preparation of adhesive ]

The adhesive is prepared by mixing the components (a) to (c) to prepare a photocurable resin composition. In this case, the components (d) to (g) are mixed as required.

In the production of the connected printing plates described above, the adhesive is injected into the gap between the side surfaces 1b of the 2 printing plates 1 to be connected [ see fig. 1 (a) and (b) ], and cured by irradiation with active energy rays such as ultraviolet rays.

In the above embodiment, the connected printing plates 1 may be set to 2 sheets, or 3 sheets or more. The direction of connection may be not a single direction (lateral direction), but a direction perpendicular thereto (longitudinal direction), or may be both directions (longitudinal and lateral directions).

Hereinafter, examples are described together with comparative examples and conventional examples. However, the present invention is not limited to the embodiments.