Print version

Abstract

The present invention provides a large-sized printing plate in which a plurality of printing sheets each having a printing surface are joined together, and in which the joining portions (resin-hardened portions) have improved resistance to breakage. [Solution] A printing plate (10) having a plurality of printing sheets (13, 14), a connecting sheet connecting the plurality of printing sheets (13, 14), and a resin curing portion (5) bonding the third surfaces (4, 24) of the plurality of printing sheets (13, 14) together, wherein at least two of the plurality of printing sheets (13, 14) have a substantially rectangular shape with two adjacent corners cut out in a plan view, and the at least two printing sheets (13, 14) have cutout surfaces (8, 9, 18, 19) formed by the cutout corners of the third surfaces (4, 24), and the third surfaces (4, 24) face each other across the resin curing portion (5), and are adhesively fixed onto the connecting sheet so that the third surfaces (4, 24) are parallel to each other.

Description

[Technical Field]

[0001] SUMMARY The present disclosure relates to a printing plate having multiple printing sheets. [Background technology]

[0002] In recent years, alignment films and insulating films have often been formed on the surfaces of TFT substrates and color filter substrates used in LCD TVs by flexographic printing. LCD TVs are becoming larger every year, and correspondingly, the printing plates used in flexographic printing must also become larger. To enlarge the printing plate, the size must be increased to, for example, about 2500 mm x 3000 mm. However, since such large printing plates cannot be manufactured using existing equipment, it is considered to enlarge the existing equipment itself. However, doing so would increase costs significantly.

[0003] Therefore, a printing plate has been proposed that is larger than the printing plate itself, made by joining multiple printing plates of a size that can be manufactured using existing equipment (see, for example, Patent Document 1). This large printing plate is obtained by butting the sides of the joined printing plates together with a gap between them, injecting an adhesive into the gap, and then allowing it to harden. Generally, a photocurable resin is used as the material for forming the printing plate, and the adhesive that joins the sides of the printing plates together is also made of the same material (photocurable resin) as the printing plate.

[0004] In the flexographic printing method, a printing plate is attached to the outer peripheral surface of a cylindrical plate cylinder, and while the plate cylinder is rotating, ink, which is a material for forming the alignment film, insulating film, etc., is supplied to the printing plate, and the ink is transferred to a printing object such as a glass substrate. Therefore, the printing plate has flexibility to the extent that it can be removably attached to the outer peripheral surface of the plate cylinder, and the connecting portion (resin-hardened portion) of the printing plate also has flexibility to be removably attached to the outer peripheral surface of the plate cylinder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-274310 Summary of the Invention [Problem to be solved by the invention]

[0006] However, these larger printing plates may have their connecting portions (resin-cured portions) broken due to their extended use or depending on the method of cleaning the printing plate. If the connecting portions (resin-cured portions) break, the printing plate can be replaced with a new one, but if such breaks occur frequently, the printing work will have to be interrupted more frequently, which reduces work efficiency and increases the cost of replacing the printing plate.

[0007] The present invention has been developed in consideration of these circumstances, and provides a large printing plate made by connecting multiple printing sheets having printing surfaces, in which the connecting parts (resin-hardened parts) have improved break resistance. [Means for solving the problem]

[0008] In order to solve the above problems, the present inventors have focused on the shape of the connecting portions (resin-cured portions) that connect a plurality of print sheets and conducted extensive research. As a result, the inventors discovered that the fracture resistance of the connecting portion (resin-cured portion) can be improved by adhesively fixing the plurality of printed sheets, among which at least two printed sheets have an approximately rectangular shape in a plan view with two adjacent corners cut out, and the at least two printed sheets have two cutout surfaces on the third surface formed by the cutout corners, with the third surfaces facing each other across the resin-cured portion and parallel to each other, thereby completing the present disclosure.

[0009] That is, the present disclosure has the following aspects. [1] A printing plate having a plurality of printing sheets, each having a first surface that is a printing surface and a second surface that is an adhesive surface; a connecting sheet that is adhered to the adhesive surfaces of the plurality of printing sheets and connects the plurality of printing sheets; and a resin curing portion that adheres the third surfaces of the plurality of printing sheets together, wherein at least two of the plurality of printing sheets have a substantially rectangular shape in a plan view with two adjacent corners cut out, and the at least two printing sheets have two cutout surfaces formed by the notched corners on the third surfaces, and the third surfaces are opposed across the resin curing portion, and are adhesively fixed on the connecting sheet so that the third surfaces are parallel to each other. [2] At least one of the cut corners of the printing sheet is located at a position K on a side parallel to the connecting direction of the printing sheet. L and a point K on the side of the printing sheet that contacts the cured resin portion. W The printing plate according to [1], wherein the printing plate is cut out to include the [3] When the length of the side parallel to the connecting direction of the printing sheet is L and the vertex of the corner before being cut out is C, the length L of the side is 500 mm or more and less than 1200 mm, and the distance from the vertex C to the point K L The relationship between the distance L1 to the point K and the length L is within the range (I) below, and when the length of the side of the printing sheet that contacts the resin-cured portion is W and the apex of the corner before being cut out is C, the length W of the side is 1400 mm or more and less than 2000 mm, and the distance from the apex C to the point K is W The printing plate according to [2], wherein the relationship between the distance W1 to the printing plate and the length W is within the range (II) below. (I) L1<0.047L (II) W1<0.018W [4] When the length of the side parallel to the connecting direction of the printing sheet is L and the vertex of the corner before being cut out is C, the length L of the side is 1200 mm or more and less than 1700 mm, and the distance from the vertex C to the point K LThe relationship between the distance L1 to the point K and the length L is within the range (III) below, and when the length of the side of the printing sheet that contacts the resin-cured portion is W and the apex of the corner before being cut out is C, the length W of the side is 2000 mm or more and less than 2800 mm, and the distance from the apex C to the point K W The printing plate according to [2], wherein the relationship between the distance W1 to the printing plate and the length W is within the range (IV) below. (III) L1<0.05L (IV) W1<0.027W [5] A printing plate described in any of [1] to [4], wherein the printing surface of the printing sheet has a central region where a printing convex portion is formed and a peripheral region surrounding the central region, and at least one of the cut-out corners of the printing sheet is formed only in the peripheral region. [6] The printing plate according to any one of [1] to [5], wherein at least one of the cut-out corners of the printing sheet is a linear cut-out. [7] The printing plate according to any one of [1] to [6], which has four printing sheets, and the four printing sheets are connected in a line in the longitudinal direction of the printing plate. [8] A printing plate according to any one of [1] to [6], which has three printing sheets, the three printing sheets being connected in a line in the longitudinal direction of the printing plate, and the printing sheet located in the middle of the line being approximately rectangular in plan view with four corners cut out. [Effects of the Invention]

[0010] The present disclosure provides a printing plate that is enlarged by connecting multiple printing sheets, and by forming the end of the connecting portion of the printing plate into a specific shape, it is possible to distribute the load on the connecting portion throughout the entire printing plate and prevent excessive load from being applied to a specific location. This improves the break resistance of the connecting portion and the durability of the entire printing plate. [Brief explanation of the drawings]

[0011] [Figure 1]FIG. 1 is a plan view schematically illustrating the configuration of a printing plate according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged view of the cross section XX of the part surrounded by the circle Y in FIG. [Figure 3] FIG. 3(A) is a plan view illustrating a printing sheet of a printing plate according to one embodiment of the present disclosure, and FIG. 3(B) is a side view of the printing sheet of FIG. 3(A) as viewed from the side indicated by the arrow. [Figure 4] FIG. 4 is a diagram illustrating the shape of a notch in a printing sheet of a printing plate according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a plan view schematically showing a printing plate according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a plan view schematically showing a printing plate according to an embodiment of the present disclosure. [Figure 7] 7(A) to 7(F) are diagrams illustrating variations in the shape of the notch in the printing sheet of the printing plate according to an embodiment of the present disclosure. [Figure 8] FIG. 8(A) is a diagram illustrating a test piece used in a bending test, and FIG. 8(B) is a diagram illustrating a testing method for the bending test. [Figure 9] FIG. 9(A) is a diagram illustrating a test piece used in a clip test, and FIG. 9(B) is a diagram illustrating a test method for the clip test. [Figure 10] FIG. 10(A) is a diagram illustrating a test piece used in a tensile strength test, and FIG. 10(B) is a diagram illustrating a test method for the tensile strength test. [Figure 11] Figure 11(A) is a diagram illustrating the state of a printing plate according to one embodiment of the present disclosure before it is immersed in the treatment liquid in the liquid tank, and Figure 11(B) is a diagram illustrating the state after it has been immersed in the treatment liquid in the liquid tank. [Figure 12] 12(A) to 12(C) are diagrams illustrating changes over time in a liquid tank of a printing plate according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure will be described below based on examples of modes for carrying out the present disclosure, although the present disclosure is not limited to the embodiments described below.

[0013] In the present disclosure, for numerical ranges described in stages, the upper or lower limit of a numerical range in one stage can be arbitrarily combined with the upper or lower limit of a numerical range in another stage. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit of the numerical range can also be replaced with the value shown in the examples.

[0014] First Embodiment FIG. 1 is a plan view schematically showing a printing plate 10 according to an embodiment of the present disclosure, and FIG. 2 is an enlarged view of the cross section XX of the part surrounded by a circle Y in FIG. The printing plate 10 of the present disclosure is formed by connecting two flexible printing sheets 13, 14. The printing sheets 13, 14 are connected by a connecting sheet 3 adhered to the second surfaces 2, 22 of the printing sheets 13, 14 and a resin curing portion 5 adhered to the third surfaces 4, 24 of the printing sheets 13, 14. The resin curing portion 5 is also adhered to the adhesive surface 15 of the connecting sheet 3.

[0015] The printed sheets 13 and 14 have first surfaces 1 and 21 that are printed surfaces and second surfaces 2 and 22 that are adhesive surfaces, and each has a substantially rectangular shape with two adjacent corners cut out in a plan view (see FIG. 3). The printing sheets 13, 14 have the third surfaces 4, 24 each having two cutout surfaces 8, 9, 18, 19, the third surfaces 4, 24 facing each other across the resin cured portion 5, and are adhesively fixed onto the connecting sheet 3 so that the third surfaces 4, 24 are parallel to each other, and the resin cured portion 5 fills the gaps between the third surfaces 4, 24 (including the gaps between the cutout surfaces 8, 18 and the gaps between the cutout surfaces 9, 19).

[0016] The print sheets 13 and 14 will be described in more detail below, but in the embodiment of the present disclosure, the print sheets 13 will be described as a representative because the print sheets 13 and 14 have the same shape (symmetrical). As shown in FIG. 3(A), the printing sheet 13 has a first surface 1 which is the printing surface, a second surface 2 which is the adhesive surface, and a third surface 4 which contacts the resin cured portion 5. The third surface 4 has a substantially rectangular shape with two adjacent corners 6 and 7 cut out when the print sheet 13 is viewed from above. As shown in FIG. 3(B), the third surface 4 has cutout surfaces 8 and 9 formed by the cutout corners 6 and 7.

[0017] The cutout surfaces 8 and 9 will be described in more detail, but in the embodiment of the present disclosure, the cutout surfaces 8 and 9 have the same shape (symmetrical), so the cutout surface 8 will be described as a representative. The cutout surface 8 is formed by cutting out the corner portion 6. The cutting out method is not particularly limited, but as shown in FIG. 4, the cutout surface 8 is formed at a position K on a side parallel to the connecting direction of the printing sheet 13. L and a point K on the side of the printing sheet 13 that contacts the resin cured portion 5. W It is preferable that the cutout is made so as to include the At this time, the location K L and section K W As long as the cutout is formed so as to include the above, the cutout may be formed in a straight line or a curved line.

[0018] In the present disclosure, the length L of the side of the print sheet 13 parallel to the connecting direction is usually in the range of 500 to 1700 mm, and preferably in the range of 600 to 1520 mm. The length W of the side of the print sheet 13 that contacts the resin-cured portion 5 is usually in the range of 1400 to 2800 mm, and preferably in the range of 1560 to 2600 mm.

[0019] <Relationship between the length of the side parallel to the connecting direction of the print sheet and the notch> When the length of the side parallel to the connecting direction of the printing sheet 13 is L and the vertex of the corner 6 before being cut is C, the distance from the vertex C to the point K L The preferable relationship between the distance L1 to the edge and the length L varies depending on the length L of the side.

[0020] [When the side length L is 500 mm or more and less than 1200 mm] When the length of the side parallel to the connecting direction of the printing sheet 13 is L, if the length L of the side is in the range of 500 mm or more and less than 1200 mm, when the vertex of the corner 6 before being cut is C, the distance from the vertex C to the point K L The relationship between the distance L1 to the target and the length L is preferably L1<0.047L, and more preferably L1<0.027L. In this case, the length of the distance L1 is, for example, preferably 2 to 70 mm, more preferably 7 to 28 mm, and even more preferably 12 to 16 mm.

[0021] [When the side length L is 1200 mm or more and less than 1700 mm] When the length of the side parallel to the connecting direction of the printing sheet 13 is L, if the length L of the side is in the range of 1200 mm to 1700 mm, and the vertex of the corner 6 before being cut out is C, the distance from the vertex C to the point K L The relationship between the distance L1 to the target and the length L is preferably L1<0.05L, more preferably L1<0.021L, and even more preferably L1<0.012L. In this case, the length of the distance L1 is, for example, preferably 2 to 70 mm, more preferably 7 to 28 mm, and even more preferably 12 to 16 mm.

[0022] <Relationship between the length of the edge that contacts the cured resin part of the print sheet and the notch> When the length of the side of the printing sheet 13 that is in contact with the resin cured portion 5 is W and the vertex of the corner before being cut out is C, the distance from the vertex C to the point K WThe preferable relationship between the distance W1 to the edge and the length W varies depending on the length W of the side.

[0023] [When the side length W is 1400mm or more and less than 2000mm] When the length of the side of the printing sheet 13 that is in contact with the resin cured portion 5 is W and the vertex of the corner before being cut out is C, the distance from the vertex C to the point K W The relationship between the distance W1 to the target and the length W is preferably W1<0.018W, and more preferably W1<0.009W. In this case, the length of the distance W1 is, for example, preferably 2 to 70 mm, more preferably 7 to 28 mm, and even more preferably 12 to 16 mm.

[0024] [When the side length W is 2000mm or more and less than 2800mm] When the length of the side of the printing sheet 13 that is in contact with the resin cured portion 5 is W and the vertex of the corner before being cut out is C, the distance from the vertex C to the point K W The relationship between the distance W1 to the target and the length W is preferably W1<0.027W, more preferably W1<0.012W, and even more preferably W1<0.0067W. In this case, the length of the distance W1 is, for example, preferably 2 to 70 mm, more preferably 7 to 28 mm, and even more preferably 12 to 16 mm.

[0025] When the first surface 1 of the printing sheet 13 is formed as a printing surface having a central region 11 in which a printing convex portion is formed and a peripheral region 12 surrounding the central region 11, the cut-out corners 6, 7 of the printing sheet 13 may be formed across the central region 11, but since adjusting the height difference between the central region 11 and the peripheral region 12 becomes complicated, it is preferable that at least one of the cut-out corners 6, 7 is formed only in the peripheral region 12.

[0026] To prepare the printing plate 10 of the present disclosure, first, one connecting sheet 3 having an area substantially equal to the area of ​​the printing plate to be prepared and one surface of which has adhesive surface 15 is prepared. Next, the second surfaces 2, 22 of the two printed sheets 13, 14 to be connected are adhered to the adhesive surface 15 of the connecting sheet 3. At this time, the third surfaces 4, 24 of the printed sheets 13, 14 are opposed to each other and parallel to each other with a gap therebetween. Then, an adhesive is injected into the gap and then cured. As a result, the area where the adhesive was injected becomes a cured resin portion 5, which adheres to the adhesive surface 15 of the connecting sheet 3 and also adheres the opposing third surfaces 4, 24 of the printing sheets 13, 14. In this manner, the two printing sheets 13 and 14 are connected by the connecting sheet 3 and the resin curing portion 5, and the printing plate 10 of the present disclosure can be produced (see FIG. 1).

[0027] The printing plate 10 of the present disclosure is used in flexographic printing and is flexible enough to be detachably attached to the outer peripheral surface of a cylindrical plate cylinder. Examples of materials forming the printing sheets 13, 14 of such a printing plate 10 include resins such as photocurable resins.

[0028] The connecting sheet 3 is composed of a sheet-like substrate and a pressure-sensitive adhesive layer formed on one side of the substrate. The side on which the pressure-sensitive adhesive layer is formed is the second side 2 (adhesive side). The base material is made of a synthetic resin such as PET (polyethylene terephthalate) and has a thickness set within the range of 0.1 to 0.5 mm. The pressure-sensitive adhesive layer is made of, for example, an acrylic resin and is applied to one surface of the substrate using a coater or the like, and the thickness is set to a range of 5 to 50 μm.

[0029] In addition to being resistant to breakage, the resin-cured portion 5 preferably has flexibility sufficient to allow the linked printing plates to be detachably attached to the outer peripheral surface of a cylindrical plate cylinder used in flexographic printing. Examples of materials (adhesives) for forming such resin-cured portion 5 include photocurable resin compositions containing the following (a) to (c): (a) An unsaturated polyurethane prepolymer containing a hydrogenated polybutadiene structure. (b) (meth)acrylate monomers. (c) Photopolymerization initiator. In the present disclosure, "(meth)acrylate" means either or both of acrylate and methacrylate.

[0030] The adhesive is prepared as a photocurable resin composition by mixing the components (a) to (c) and, if necessary, other components (e.g., a silane coupling agent, a flexibility imparting agent, various additives, etc.).

[0031] When a photocurable resin composition is used as the adhesive, it is injected into the gap between the third surfaces 4, 24 of the printing sheets 13, 14 described above, and then irradiated with active energy rays such as ultraviolet rays, thereby forming a resin cured portion 5 that bonds the printing sheets 13, 14.

[0032] According to the printing plate 10 of the present disclosure, even though the printing sheets 13 and 14 are connected to each other and the printing plate 10 is enlarged, the load on the connecting portion can be distributed throughout the printing plate 10 by forming a specific shape at the end of the resin-cured portion 5, which is the connecting portion of the printing sheets 13 and 14. This improves the break resistance of the connecting portion (the resin-cured portion 5) and also improves the durability of the printing plate 10 itself.

[0033] Incidentally, the printing plate 10 may be immersed in a liquid bath for pre-treatment, cleaning, or the like. For example, as shown in Figure 11(A), a mounting table 70 for placing the printing plate 10 thereon is provided, and the printing plate 10 is brought close to a liquid tank 72 filled with a processing liquid 71 or the like, with both ends of the printing plate 10 clamped between devices 73 and the central portion bent downward, and after the central portion of the printing plate 10 abuts against the mounting table, the clamping of both ends of the printing plate 10 is released, and the printing plate 10 can be placed on the mounting table 70 and immersed in the processing liquid 71, as shown in Figure 11(B).

[0034] At this time, the state of the printing plate 10 changes from a state in which the central portion is bent downward as shown in Figure 12(A) to a state in which the central portion is bent upward as shown in Figure 12(B), and downward bending occurs at two locations outside the central portion.Through this state, the printing plate 10 changes to a state in which the printing plate is bent upward along the mounting table as shown in Figure 12(C).At this time, in each state, a greater load is applied to the location indicated by the downward arrow (the location where bending occurred).Note that the configuration of the printing plate 10 is omitted in Figures 12(A) to (C).

[0035] In such a case, the printing plate 10 of the present disclosure has enhanced resistance to breakage of the cured resin portion 5 between the printing sheets 13 and 14, and therefore can exhibit durability in any of the states shown in Figures 12(A) to (C).

[0036] In the first embodiment, the shape created by butting together the cut-out corners of the two printing sheets (the shape surrounded by the cut-out surfaces 8, 18, the imaginary line Z, and the edge of the printing plate 10) is approximately an isosceles triangle (see Figure 1), but as mentioned above, it may be another shape depending on the shape of the cut-out of the printing sheets. As for other shapes, for example, if the cutout surface 8 on the third surface 4 of the printed sheet 13 is formed as an arc-shaped cutout that convex inward in a planar view, the shape created when the cutout corners of the two printed sheets are butted together will be as shown in Figure 7(A), and if the cutout surface 8 on the third surface 4 of the printed sheet 13 is formed as an arc-shaped cutout that convex outward in a planar view, the shape created when the cutout corners of the two printed sheets are butted together will be as shown in Figure 7(B).

[0037] Furthermore, if the cutout surface 8 on the third surface 4 of the printed sheet 13 is formed as a sinusoidal cutout in a planar view, the shape created when the cutout corners of the two printed sheets are butted together will be as shown in Figure 7(C), and if the cutout surface 8 on the third surface 4 of the printed sheet 13 is formed as a curved cutout consisting of a combination of multiple waves in a planar view, the shape created when the cutout corners of the two printed sheets are butted together will be as shown in Figure 7(D).

[0038] Furthermore, if the cutout surface 8 on the third surface 4 of the printed sheet 13 is formed as a straight cutout that bends at a right angle in a planar view, the shape created when the cutout corners of the two printed sheets are butted together will be as shown in Figure 7(E), and if the cutout surface 8 on the third surface 4 of the printed sheet 13 is formed as a straight cutout that has multiple bends in a planar view, the shape created when the cutout corners of the two printed sheets are butted together will be as shown in Figure 7(F).

[0039] In the first embodiment, the cutout shapes of the printing sheets 13 and 14 are formed symmetrically with respect to the resin-cured portion 5, but this is not necessarily required. However, symmetry tends to improve the break resistance of the resin-cured portion 5.

[0040] <Second embodiment> FIG. 5 is a plan view schematically showing a printing plate 30 according to an embodiment of the present disclosure. The printing plate 30 of the present disclosure is formed by joining four flexible printing sheets 31, 32, 33, and 34 together. Here, like the printed sheets described in the first embodiment, printed sheets 32 and 33 have central regions 42 and 44 and peripheral regions 43 and 45 on their first surfaces (printed surfaces), and have cutout surfaces 38, 39, 40 and 41 on their third surfaces. On the other hand, printed sheets 31 and 34 are smaller than printed sheets 32 and 33, and have a generally rectangular shape in plan view with no cutout corners. The printing sheets 31, 32, 33, and 34 are arranged in a row in the longitudinal direction of the printing plate 30, with gaps between them so that they are parallel to each other on a connecting sheet (not shown), and they are connected to the resin curing portions 35, 36, and 37 by the connecting sheet.

[0041] To prepare the printing plate 30 of the present disclosure, first, two adjacent corners of the two prepared printing sheets in plan view are cut at the positions K shown in FIG. 4 in the same manner as the printing plate 10. L and section K W (See reference numerals 38, 39, 40, and 41 in FIG. 5). At this time, from the vertex C to the point K L Distance L1 from the vertex C to the point K W The preferred range of the distance W1 to the printing plate 10 is the same as that of the printing plate 10. In this way, printing sheets 32 and 33 are produced, each having two cutout surfaces formed by the notched corners on the third surface. Next, a photosensitive resin composition (K-11, manufactured by Asahi Kasei Corporation) is irradiated with ultraviolet light and cured to produce printing sheets (for edges) 31, 34, which have a length L in the range of 1265 to 1320 mm and a length W and thickness designed in the same way as the printing sheets 32, 33, to be located at both ends of the printing plate (for edges). Then, the two print sheets 32, 33 are adhesively fixed onto the connecting sheet with the third surfaces facing each other, the distance (gap) between the third surfaces being 1.5 to 4.0 mm, and the third surfaces being parallel to each other. In addition, the two print sheets fixed on the connecting sheet are adhered and fixed on the connecting sheet so that they are parallel to each other, with a distance (gap) of 1.5 to 4.0 mm between them. The desired printing plate 30 can be obtained by injecting adhesive into the gaps between the printing sheets 31 and 32, the gap between the printing sheets 32 and 33, and the gap between the printing sheets 33 and 34, and then irradiating ultraviolet light to harden the adhesive and create resin-hardened portions 35, 36, and 37.

[0042] The materials of the components constituting the printing plate 30 can be the same as those described in the first embodiment, and the preferred materials and the like are also the same. The shape of the cutout surface and the like of the printing plate 30 can also be the same as those described in the first embodiment, and the preferred ranges thereof are also the same.

[0043] According to the printing plate 30 of the present disclosure, even though the printing sheets 31, 32, 33, and 34 are connected to each other and the printing plate 30 is enlarged, the load on the connecting portion (resin-cured portion 36) can be distributed throughout the printing plate 30 by forming the end of the connecting portion (resin-cured portion 36) into a specific shape, thereby preventing excessive load from being applied to a specific location. This improves the break resistance of the connecting portion (resin-cured portion 36) and improves the durability of the printing plate 30 itself.

[0044] Furthermore, when the printing plate 30 of the present disclosure is immersed in a liquid bath for pretreatment, cleaning, or the like, it changes from a state in which the center is bent downward as shown in Fig. 12(A) to a state in which two outer locations of the center are bent downward as shown in Fig. 12(B), and then changes to a state in which it is bent upward along the mounting table as shown in Fig. 12(C).In each state, a greater load is applied to the locations indicated by the downward arrows, but because the fracture resistance of the cured resin portion 36 is enhanced, the printing plate 30 can exhibit durability similar to that of the printing plate 10 in any of the states shown in Figs. 12(A) to (C).Note that the configuration of the printing plate 30 is omitted from the illustrations of Figs. 12(A) to (C).

[0045] <Third embodiment> FIG. 6 is a plan view schematically showing a printing plate 50 according to an embodiment of the present disclosure. The printing plate 50 of the present disclosure is formed by connecting three flexible printing sheets 51, 52, and 53 together. Here, the printing sheets 51, 52, 53, like the printing sheets described in the first embodiment, have central regions 63, 65, 67 and peripheral regions 64, 66, 68 on their first surfaces (printing surfaces), and have cutout surfaces 46, 56, 57, 58, 59, 60, 61, 62 on their third surfaces. That is, of the three print sheets 51, 52, and 53, the print sheet 52 disposed in the middle has two of the third surfaces and four cutout surfaces (cutout surfaces 57, 58, 59, and 60). The printing sheets 51, 52, and 53 are arranged in a row in the longitudinal direction of the printing plate 50, with gaps between them so that they are parallel to each other on a connecting sheet (not shown), and they are connected to the resin curing portions 54 and 55 by the connecting sheet.

[0046] To prepare the printing plate 50 of the present disclosure, first, two of the three prepared printing sheets are cut at two adjacent corners in a plan view at the positions K shown in FIG. 4 in the same manner as the printing plate 10. L and section K W (See reference numerals 46, 56, 61, and 62 in FIG. 6). At this time, from the vertex C to the point K L Distance L1 from the vertex C to the point K W The preferred range of the distance W1 to the printing plate 10 is the same as that of the printing plate 10. In this way, printing sheets 51 and 53 are produced, each having two cutout surfaces formed by the notched corners on the third surface. The remaining sheet has all corners aligned at the positions K shown in FIG. 4 in the same manner as the two previous printed sheets. L and section K WThe printing sheet 52 is cut out so as to include the point K (see reference numerals 57, 58, 59, and 60 in FIG. 6), and the third surface and the surface opposite to the third surface have two cutout surfaces formed by the cut-out corners. L Distance L1 from the vertex C to the point K W The preferred range of the distance W1 to the printing plate 10 is the same as that of the printing plate 10. Then, printed sheet 52 with all corners cut out is placed in the center, and printed sheets 51 and 53 with two corners cut out on either side are placed facing the third surfaces (or the surfaces opposite the third surfaces), the distance (gap) between the third surfaces is 1.5 to 4.0 mm, and the third surfaces (or the surfaces opposite the third surfaces) are adhesively fixed onto the connecting sheet so that they are parallel to each other. The desired printing plate 50 can be obtained by injecting adhesive into the gap between the printing sheets 51 and 52 and the gap between the printing sheets 52 and 53, and then irradiating ultraviolet light to harden the adhesive and create resin-hardened portions 54 and 55.

[0047] The materials of the components constituting the printing plate 50 can be the same as those described in the first embodiment, and the preferred materials and the like are also the same. The shape of the cutout surface and the like of the printing plate 50 can also be the same as those described in the first embodiment, and the preferred ranges thereof are also the same.

[0048] According to the printing plate 50 of the present disclosure, even though the printing sheets 51, 52, and 53 are connected to each other and the printing plate 50 is enlarged, the load on the connecting portions (resin-cured portions 54, 55) can be distributed throughout the printing plate 50 by forming the ends of the resin-cured portions 54, 55, which are the connecting portions of the printing sheets 51, 52, and 53, into specific shapes, thereby preventing excessive load from being applied to specific locations. This improves the break resistance of the connecting portions (resin-cured portions 54, 55) and the durability of the printing plate 50 itself.

[0049] Furthermore, when the printing plate 50 of the present disclosure is immersed in a liquid tank for pre-processing, cleaning, etc., it changes from a state in which the center is bent downward as shown in Figure 12(A) to a state in which downward bending occurs at two points outside the center as shown in Figure 12(B), and through this state to a state in which it is bent upward along the mounting table as shown in Figure 12(C), and in each state, more load is applied to the points indicated by the downward arrows. However, since the printing plate 50 has increased resistance to breakage in the resin-hardened portions 54 and 55, which are the connecting portions of the printing sheets 51, 52, and 53, the downward bending portions that occur at two locations outside the center of the printing plate 50, particularly in the state shown in Figure 12(B), correspond to the resin-hardened portions 54 and 55, thereby increasing the durability of the printing plate 50. 12(A) to 12(C), the configuration of the printing plate 50 is omitted. [Example]

[0050] Next, in order to demonstrate the effects of the present disclosure, a bending test, a clip test, and a tensile strength test were carried out as described below.

[0051] First, the following materials were prepared as the materials for forming the printing plate. Using these materials, test pieces suitable for the respective tests were prepared as described below.

[0052] Printing sheets (printed substrate sheets) A photosensitive resin composition (K-11, manufactured by Asahi Kasei Corporation) was cured by irradiating it with ultraviolet light, and a plurality of print sheets (print substrate sheets: thickness 2.56 mm) of a predetermined size were produced. This is a substrate sheet before the printing surface is formed, and a printing sheet having a printing surface can be produced by forming convex portions and concave portions on this substrate sheet by photolithography or the like. Connecting sheet An isocyanate-based crosslinking agent was added in an amount of 0.5% by mass relative to the mass of the (meth)acrylic acid ester copolymer, and the mixture was stirred for 10 minutes to obtain a pressure-sensitive adhesive solution. The pressure-sensitive adhesive solution was then applied to one side of a PET sheet substrate (thickness: 250 μm) of a predetermined size using a coater, and then dried at 100°C for 3 minutes to form a pressure-sensitive adhesive layer (thickness: 30 μm). In this way, a connecting sheet having a pressure-sensitive adhesive layer on one side was produced. ·glue A photocurable resin composition was prepared by mixing 50 parts of an unsaturated polyurethane prepolymer (number average molecular weight 15,000) containing a hydrogenated polybutadiene structure, 30 parts of tricyclo[5.2.1.0(2,6)]decan-8-yl methacrylate, 13 parts of 2-ethylhexyl acrylate, 3 parts of 2-methoxyethyl acrylate, and 4 parts of diethoxyacetophenone (photopolymerization initiator). Note that in this disclosure, "parts" refers to parts by mass.

[0053] <<Bending test>> Test pieces (Example 1 and Comparative Example 1) based on the examples and comparative examples of the present disclosure were prepared, and durability to forces applied in the bending direction was evaluated, assuming the conditions under which a printing plate would be used, as shown below.

[0054] [Example 1] A test piece 80 shown in FIG. 8(A) was prepared as follows. First, the two prepared printed circuit board sheets were each formed into a rectangle measuring 100 x 250 mm, and then two adjacent corners in a plan view were cut to have L1 of 14 mm, W1 of 14 mm, and K L and K. W The printed circuit board sheets 83 and 84 were fabricated with a third surface having two cutout surfaces formed by the cut-out corners (see FIG. 4). Next, the two printed substrate sheets were adhesively fixed onto the connecting sheet so that their third surfaces faced each other, the distance between the third surfaces (gap excluding the ends) was 2.0 mm, and the third surfaces were parallel to each other. Then, adhesive was injected into the gap between the two printed substrate sheets and cured by irradiating with ultraviolet light, thereby obtaining a test piece 80 having a width P of 250 mm and a length Q of 202 mm, in which the gap was filled with a resin cured portion 85, which corresponds to the disclosed embodiment.

[0055] [Comparative Example 1] A test piece 81 corresponding to a comparative example of the present disclosure was obtained in the same manner as in Example 1, except that two adjacent corners of the two printed substrate sheets in plan view were not cut out. In other words, the shape of the resin-cured portion of Comparative Example 1 is the same as that of a conventional printing plate.

[0056] [Bending test evaluation] For test pieces 80 and 81 of Example 1 and Comparative Example 1, as shown in FIG. 8(B), each was wound around roll 82 with the connecting sheet side facing inward and having a diameter R (curve radius R 100 mm), and the state of each cured resin portion was visually observed, and the time until the cured resin portion broke (fractured) was measured. As a result, in Example 1 (test piece 80), no damage (breakage) was observed in the resin-hardened portion 85 even after 48 hours, whereas in Comparative Example 1 (test piece 81), breakage was observed near the center of the resin-hardened portion after 11 hours. Thus, it was found that the present disclosure is superior in durability to conventional products.

[0057] <<Clip test>> Test specimens (Example 2 and Comparative Example 2) according to the examples and comparative examples of the present disclosure were prepared, and durability to forces applied in the bending direction was evaluated assuming a higher degree of bending as shown below.

[0058] [Example 2] A test piece 90 shown in FIG. 9(A) was produced in accordance with Example 1. That is, the two prepared printed board sheets were each formed into a rectangle measuring 57.5 mm x 100 mm, and then two adjacent corners in a plan view were cut to have L1 of 14 mm, W1 of 14 mm, and K L and K. WThe printed circuit board sheets 92 and 93 were fabricated so that the third surfaces had two cutout surfaces formed by the cut-out corners (see FIG. 4). Next, the two printed substrate sheets were adhesively fixed onto the connecting sheet so that the third surfaces faced each other, the distance (gap) between the third surfaces was 2.0 mm, and the third surfaces were parallel to each other. Then, adhesive was injected into the gap between the two printed substrate sheets and cured by irradiating with ultraviolet light, thereby obtaining a test piece 90 having a width P of 100 mm and a length Q of 117 mm, in which the gap was filled with a resin cured portion 95, which corresponds to an embodiment of the present disclosure.

[0059] Comparative Example 2 A test piece 91 corresponding to a comparative example of the present disclosure was obtained in the same manner as in Example 2, except that two adjacent corners of the two printed substrate sheets in plan view were not cut out. In other words, the shape of the resin-cured portion of Comparative Example 2 is the same as that of a conventional printing plate.

[0060] [Evaluation of clip test] Test pieces 90 and 91 of Example 2 and Comparative Example 2 were each curved so that the connecting sheet side was facing inward, as shown in Fig. 9(B), and a point 15 mm from the end was clipped with a tool 94 to maintain the curved state. Then, the state of the cured resin part of test pieces 90 and 91 was visually observed, and the time until the cured resin part broke (fractured) was measured. As a result, in Example 2 (test piece 90), no damage (breakage) was observed in the resin-hardened portion 95 even after 48 hours, whereas in Comparative Example 2 (test piece 91), breakage was observed near the center of the resin-hardened portion after 8 hours. Thus, it was found that the present disclosure has superior durability compared to conventional products even when subjected to a high degree of bending.

[0061] <<Tensile strength test>> Test pieces (Example 3 and Comparative Example 3) according to the examples and comparative examples of the present disclosure were prepared, and the tensile strength in the longitudinal direction was measured as follows.

[0062] [Example 3] A test piece 100 shown in FIG. 10(A) was produced in accordance with Example 1. That is, the two prepared printed board sheets were each formed into a rectangle of 100 mm x 200 mm, and then two adjacent corners in a plan view were cut to have L1 of 14 mm, W1 of 14 mm, and K L and K. W The printed circuit board sheets 102 and 103 were fabricated by cutting out the third surface at a position where the straight line connecting the above was formed (see FIG. 4) and having two cutout surfaces formed by the cut-out corners. Next, the two printed board sheets 102 and 103 were adhesively fixed onto the connecting sheet so that the third surfaces faced each other, the distance (gap) between the third surfaces was 2.0 mm, and the third surfaces were parallel to each other. Then, adhesive was injected into the gap between the two printed substrate sheets and cured by irradiating with ultraviolet light, thereby obtaining a test piece 100 having a width P of 200 mm and a length Q of 202 mm, in which the gap was filled with a resin cured portion 105, which corresponds to an embodiment of the present disclosure.

[0063] Comparative Example 3 A test piece 101 corresponding to a comparative example of the present disclosure was obtained in the same manner as in Example 3, except that two adjacent corners of the two printed substrate sheets in plan view were not cut out. That is, the shape of the resin-cured portion of Comparative Example 3 is the same as that of a conventional printing plate.

[0064] [Evaluation of tensile strength test] For the test pieces 100 and 101 of Example 3 and Comparative Example 3, as shown in FIG. 10(B), the longitudinal ends were each fixed to a strength testing machine vice 104, and one of the strength testing machine vises 104 was moved away from each other to pull the test pieces 100 and 101 in the longitudinal direction. The condition of the cured resin portion of the test piece was visually observed, and the load at which fracture (breakage) occurred in the cured resin portion was measured. As a result, in Example 3 (test piece 100), fracture (breakage) was observed in the resin-hardened portion 105 at 27.43 N, whereas in Comparative Example 3 (test piece 101), fracture was observed in the resin-hardened portion at 25.10 N. As described above, it was found that the present disclosure is superior in durability to conventional products in terms of tensile strength as well.

[0065] The printing plate of this embodiment can also reduce the load placed on it during pre-processing, cleaning, etc., so even though it is a large printing plate, it has sufficient strength and also reduces manufacturing costs.

[0066] Although the above examples show specific embodiments of the present invention, the examples are merely illustrative and should not be construed as limiting. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention. [Industrial Applicability]

[0067] The printing plate of the present disclosure can be used as a large, durable printing plate. [Explanation of symbols]

[0068] 4 The Third Side 5 Resin hardening part 8 Cutout surface 9 Cutout surface 10 Print Edition 13 Printing Sheet 14 printing sheets 18 Cutout surface 19 Cutout surface 24 The Third Side

Claims

1. a plurality of printing sheets each having a first surface as a printing surface and a second surface as an adhesive surface; a connecting sheet that is adhered to the adhesive surfaces of the plurality of printing sheets and connects the plurality of printing sheets; a resin-cured portion that bonds the third surfaces of the plurality of printing sheets together, At least two of the plurality of printing sheets have a substantially rectangular shape in plan view with two adjacent corners cut out, The at least two printing sheets have two cutout surfaces formed by cut-out corners on the third surfaces, and the third surfaces are opposed to each other across the resin-cured portion, and the printing plates are adhesively fixed on the connecting sheet so that the third surfaces are parallel to each other.

2. At least one of the cut corners of the printing sheet is located at a position K on a side parallel to the connecting direction of the printing sheet. Ｌ and a point K on the side of the printing sheet that contacts the cured resin portion. Ｗ 2. The printing plate of claim 1, wherein the printing plate is cut out to include

3. When the length of the side parallel to the connecting direction of the printing sheet is L and the apex of the corner before being cut out is C, the length L of the side is 500 mm or more and less than 1200 mm, and the distance from the apex C to the point K Ｌ Distance L to １ and the length L are in the following range (I), When the length of the side of the printing sheet that contacts the resin-hardened portion is W and the apex of the corner before being cut out is C, the length W of the side is 1400 mm or more and less than 2000 mm, and the distance from the apex C to the point K Ｗ Distance to W １ and the length W are in the range (II) below. (I) L １ 70.047, (II)W １ <0.018W

4. When the length of the side parallel to the connecting direction of the printing sheet is L and the vertex of the corner before being cut out is C, the length L of the side is 1200 mm or more and less than 1700 mm, and the distance from the vertex C to the point K Ｌ Distance L to １ and the length L are in the following range (III), When the length of the side of the printing sheet that contacts the resin-hardened portion is W and the apex of the corner before being cut out is C, the length W of the side is 2000 mm or more and less than 2800 mm, and the distance from the apex C to the point K Ｗ Distance to W １ 3. The printing plate according to claim 2, wherein the relationship between the length W and the width W is within the range (IV) below. (III)L １ <0.05L (IV) W １ <0.027W

5. the printing surface of the printing sheet has a central region where printing protrusions are formed and a peripheral region surrounding the central region, 3. The printing plate of claim 1, wherein at least one of the cut-out corners of the printing sheet is formed only in the peripheral region.

6. 3. The printing plate according to claim 1, wherein at least one of the cut-out corners of the printing sheet is a straight cut-out.

7. 3. The printing plate according to claim 1, wherein the printing plate has four printing sheets, and the four printing sheets are connected in a line in the longitudinal direction of the printing plate.

8. The printing plate has three printing sheets, and the three printing sheets are connected in a state of being aligned in a line in the longitudinal direction of the printing plate, 3. The printing plate according to claim 1, wherein the printing sheet located at the center of the arranged printing plates has a substantially rectangular shape in plan view with four corners cut out.

Images