JP2017154353A - Method for manufacturing flexographic printing plate and method for manufacturing liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing such a flexographic printing plate that has excellent tensile strength in a connected portion, that endures against a tensile stress applied when a liquid crystal alignment film or the like of a large liquid crystal display element is to be printed, and that prevents tearing or peeling in the connected portion during printing a predetermined number of sheets, and a method for manufacturing a liquid crystal display element including a step of forming a liquid crystal alignment film by using a flexographic printing plate manufactured by the above method.SOLUTION: The method for manufacturing a flexographic printing plate includes the steps of treating each side face 14 of a plurality of division bodies 4 with a treating agent comprising isocyanate or its biuret complex, then arranging the division bodies 4 as spaced at a given interval in a plane direction on the same plane, filling a gap of the division bodies with a photocurable resin composition, and irradiating the photocurable resin composition with active rays to cure, and thereby bonding the division bodies with the cured product to form an ink transfer layer. The method for manufacturing a liquid crystal display element includes a step of forming a liquid crystal alignment film by flexographic printing using the above flexographic printing plate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a flexographic printing plate, and a method for manufacturing a liquid crystal display device, including a step of forming a liquid crystal alignment film of a liquid crystal display device by flexographic printing using the flexographic printing plate manufactured by the manufacturing method. It is.

Flexographic printing is used to form a liquid crystal alignment film that is required to have a high film quality that is as uniform as possible and free from pinholes and the like on the electrode forming surface of the substrate constituting the liquid crystal display element. .
Flexographic printing is made of a flexible resin sheet whose surface is in contact with the surface to be printed such as the electrode forming surface in a state where the surface of the liquid crystal alignment film is supported. A flexographic printing plate having a plate-shaped ink transfer layer that is a plate surface for transfer onto a printing surface is used.

In many cases, a reinforcing sheet made of various plastic films is laminated on the surface of the ink transfer layer opposite to the plate surface.
The flexographic printing plate is required to have as high a thickness accuracy as possible over the entire surface in order to maintain a constant printing pressure, improve printing accuracy, and form a uniform liquid crystal alignment film. In particular, recently, it has been demanded to increase the accuracy of thickness, which was conventionally about ± 30 μm, to about ± 15 μm.

However, with the recent increase in size of flexographic printing plates due to the increase in size of liquid crystal display elements, there is a problem that it is becoming difficult to maintain the thickness accuracy within the above range.
In particular, in a large flexographic printing plate with a side exceeding, for example, 1500 mm, the thickness accuracy is significantly reduced.
In view of this, it has been studied to produce a plurality of sheet-like divided bodies that serve as the basis of the ink transfer layer and to join them in the surface direction to produce a large flexographic printing plate (Patent Document 1).

  According to such a manufacturing method, since the individual divided bodies can be formed in a small size that is easy to improve the thickness accuracy, it is considered that the thickness accuracy of the entire flexographic printing plate can be improved.

JP-A-9-274310

  In the production method described in Patent Document 1, the side surfaces of each divided body to be joined to other divided bodies are first treated with a monomer having a cyanoacryl group in the molecule, and then activated in the gaps between the divided bodies. After injecting a photocurable resin composition that undergoes a curing reaction upon irradiation with light, the photocurable resin composition is subjected to a curing reaction by irradiation with the active light to join a plurality of divided bodies.

However, the tensile strength of the joint portion is not yet sufficient in the above-described conventional bonding, and flexographic printing plates are particularly affected by the tensile stress repeatedly applied when continuously printing the liquid crystal alignment film of the large liquid crystal display element described above. Tends to be torn off or peeled off from the joined portion.
In particular, in recent years, there has been a tendency to increase the number of sheets that can be continuously printed using a single flexographic printing plate from the current level, but when the tensile strength of the joint portion is not sufficient as described above, The flexographic printing plate is torn off or peeled off from the joining portion at a relatively early stage before the preset number of printed sheets, and it is easy to cause a problem that further printing cannot be continued.

The object of the present invention is excellent in the tensile strength of the joint portion, and particularly withstands a tensile stress repeatedly applied when continuously printing a liquid crystal alignment film of a large liquid crystal display element, etc. Another object of the present invention is to provide a manufacturing method for manufacturing a flexographic printing plate that is not torn off or peeled off from a joined portion.
Moreover, the objective of this invention is providing the manufacturing method of a liquid crystal display element including the process of forming a liquid crystal aligning film using the flexographic printing plate manufactured by the said manufacturing method.

The present invention is a method for producing a flexographic printing plate provided with a resin-made ink transfer layer,
A step of arranging a plurality of sheet-like divided bodies that are the basis of the ink transfer layer on the same plane at regular intervals in the surface direction (first step),
A step (second step) of filling the gap between the arrayed divided bodies with a photocurable resin composition that undergoes a curing reaction by irradiation with actinic rays, and irradiation with the actinic rays. A step of forming the ink transfer layer by joining the plurality of divided bodies to each other by a curing reaction (third step)
And a step (pretreatment step) of treating each side surface of each of the divided bodies with a treating agent containing at least one kind selected from the group consisting of isocyanate and its biuret body in advance. Is a method for producing a flexographic printing plate.

  Moreover, this invention is a manufacturing method of the liquid crystal display element including the process of forming a liquid crystal aligning film by flexographic printing using the flexographic printing plate manufactured by the manufacturing method of the said invention.

According to the present invention, it is excellent in the tensile strength of the joined portion, and particularly sufficiently withstands the tensile stress repeatedly applied when continuously printing a liquid crystal alignment film or the like of a large liquid crystal display element. In the meantime, it is possible to provide a manufacturing method for manufacturing a flexographic printing plate that is not torn off or peeled off from a joined portion.
Moreover, according to this invention, the manufacturing method of a liquid crystal display element including the process of forming a liquid crystal aligning film using the flexographic printing plate manufactured by the said manufacturing method can be provided.

It is a perspective view explaining the pre-process of the manufacturing method of the flexographic printing plate of this invention among the each process of 1st embodiment thru | or the front | former stage of a 1st process. FIGS. (A) and (b) are enlarged sectional views for explaining the latter stage of the first step. FIGS. (A) to (c) are enlarged sectional views for explaining the second to third steps. It is a perspective view which shows the plate sheet of the state which the 3rd process was complete | finished. It is a perspective view which shows an example of the flexographic printing plate finally manufactured through each process of said 1st embodiment. In 2nd embodiment of the manufacturing method of this invention, it is a perspective view which shows the plate sheet of the state which the 3rd process was complete | finished.

<Production method of flexographic printing plate>
The method for producing a flexographic printing plate of the present invention includes a first method in which a plurality of sheet-like divided bodies that form the ink transfer layer are arranged on the same plane at regular intervals in the surface direction as described above. Process,
A second step of filling the gaps between the arrayed divided bodies with a photocurable resin composition that undergoes a curing reaction by irradiation with actinic rays, and the photocurable resin composition that undergoes a curing reaction by irradiation with actinic rays. A third step of joining the plurality of divided bodies to each other to form the ink transfer layer, and the side surfaces of each of the divided bodies to be joined to the other divided bodies in advance are isocyanate and biuret thereof. It includes a pretreatment step of treating with a treating agent containing at least one selected from the group consisting of bodies.

According to the production method of the present invention described above, the side surfaces of the divided body that is the basis of the ink transfer layer that are bonded to each other by the curing reaction of the photocurable resin composition are treated in advance with the above-described treatment agent. As is clear from the results of the examples and comparative examples, the tensile strength of the joined portion can be significantly improved as compared with the conventional joining described in, for example, Patent Document 1.
For this reason, according to the manufacturing method of the present invention, it is sufficient to withstand the tensile stress repeatedly applied when continuously printing a liquid crystal alignment film or the like of a large liquid crystal display element, etc. Flexographic printing plates that are not torn off or peeled off can be produced.

  With reference to FIG. 5, the flexographic printing plate 1 manufactured by the manufacturing method according to the embodiment of the present invention covers the entire surface of the flexographic printing plate 1 for reinforcing the entire flexographic printing plate 1 in the surface direction. In a state where a plurality of (four in the figure) rectangular sheet-like divided bodies 4 of the same size are arranged in 2 rows × 2 columns close to each other in the plane direction on one reinforcing sheet 2. 4 is provided with a rectangular flat-plate-shaped ink transfer layer 6 formed by bonding 4 with a cured product 5 of a photocurable resin composition.

The cured product 5 is formed by irradiating a photocurable resin composition with an actinic ray such as ultraviolet rays and causing a curing reaction.
Further, although the plate surface 7 which is the exposed surface of the ink transfer layer 6 is partially omitted in the drawing, the patterns P _{11 to} P _xy corresponding to the x × y print patterns are The ink transfer layers 6 are arranged in a matrix corresponding to the rectangles.

Further, when the flexographic printing plate 1 is set on a flexographic printing machine, in the vicinity of two rectangular parallel sides of the flexographic printing plate 1 and on the outside of the plate surface 7, a constant for holding with a vise (not shown). A width gripping portion 61 is provided over the entire width of each side.
A groove 62 having a constant width is provided between the grip 61 and the plate surface 7 in parallel with the grip 61.

Further, the grip portion 61 has pin holes 63 for inserting fixing pins (not shown) at a plurality of locations (10 locations in the figure) in the length direction while gripping the grip portion 61 with a vise. It is formed at intervals.
In order to manufacture the flexographic printing plate 1 by the manufacturing method according to the embodiment of the present invention, first, a predetermined number of divided bodies 4 are prepared.

As the divided body 4, for example, an unpatterned material may be used, and a pattern may be formed later on the plate surface 7 of the ink transfer layer 6 formed by joining the divided bodies 4 together. Alternatively, the divided body 4 that has been patterned in advance may be used.
<Production method of flexographic printing plate>
<First embodiment>
In 1st embodiment, the division body 4 which is not pattern-formed beforehand is used.

With reference to FIGS. 2 (a) and 2 (b) and the like, examples of the divided body 4 include a laminated body of a surface resin layer 8 and a reinforcing film 9 constituting the plate surface 7.
The divided body 4 having the above laminated structure can be produced in the same manner as a conventional small flexographic printing plate.
That is, a planar mold surface (not shown) for making the plate surface 7 a predetermined surface state such as a rough surface is prepared, and the surface resin layer 8 is placed between the mold surface and the reinforcing film 9. The photocurable resin composition is irradiated with actinic rays in a state where the reinforcing film 9 is held in a parallel plate shape with a predetermined interval with respect to the mold surface while sandwiching the photocurable resin composition to be Is cured to form the surface resin layer 8. Thereafter, when the formed surface resin layer 8 is released from the mold surface, the divided body 4 is produced.

The above-mentioned divided body 4 is prepared to a size that can be obtained, for example, with one side of less than 1500 mm and having excellent thickness accuracy by a conventional technique, and is necessary to match the size of the surface layer resin layer 8 of the flexographic printing plate 1. Prepare the number of sheets (4 in the case of the figure).
Examples of the photocurable resin composition on which the surface resin layer 8 is based include various photocurable resin compositions excellent in affinity with the reinforcing film 9 and adhesiveness.

Moreover, as a photocurable resin composition used as the base of the hardened | cured material 5 which joins the several division body 4 mentioned above, it was excellent in the affinity with the said surface layer resin layer 8 and the reinforcement film 9, and adhesiveness. Various photocurable resin compositions may be mentioned.
In particular, the cured product 5 and the surface layer resin layer 8 are formed of the same photocurable resin composition, and the rubber elasticity of the ink transfer layer 6 composed of the divided body 4 including the surface layer resin layer 8 and the cured product 5 Since flexibility and the like can be made uniform over the entire surface, it is preferable.

Examples of the photocurable resin composition used as the basis of the cured product 5 and the surface resin layer 8 include a prepolymer having an 1,2-butadiene structure and having an ethylenically unsaturated double bond at the terminal, and an ethylenically unsaturated single monomer. And a composition containing a monomer and a photopolymerization initiator.
According to said photocurable resin composition, it can have the ink transfer layer 6 which has moderate rubber elasticity and a softness | flexibility, and was excellent also in solvent resistance.

In particular, a photocurable resin composition containing at least a urethane prepolymer containing a urethane bond in the main chain is preferred as the prepolymer.
Such a urethane prepolymer is synthesized, for example, by introducing at least one polymerizable ethylenic double bond at the end of a compound obtained by chain extension of a hydrogenated 1,2-polybutadiene compound with diisocyanate. Compounds and the like.

When the photo-curable resin composition containing the urethane prepolymer is used, the effect of improving the tensile strength of the joined portion by treating the side surface of the divided body 4 with the above-described treatment agent is further improved. The tensile strength can be greatly improved.
As the reinforcing film 9, various films made of a resin excellent in affinity and adhesiveness with the photocurable resin composition can be used.

Examples of the film include polyethylene (PE), polypropylene (PP), thermoplastic polyurethane (TPU), polyethylene terephthalate (PET), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and the like.
By using such a film as the reinforcing film 9, it is possible to improve the adhesion with the surface resin layer 8 made of the photocurable resin composition and the cured product 5.

(Pretreatment process)
Referring to FIG. 1, side surfaces 14 of each divided body 4 to be joined to other divided bodies 4 are first degreased with an organic solvent such as acetone or tetrahydrofuran as necessary, and then dried. It is treated with a treating agent containing at least one selected from the group consisting of the isocyanate and its biuret.

As the isocyanate contained in the above-mentioned treatment agent, various compounds having 1 or more, especially 2 or more, and 4 or less, particularly 3 or less in the molecule can be used as the isocyanate. It is.
Among them, at least one selected from the group consisting of dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate, triphenylmethane-4,4 ′, 4 ″ -triisocyanate, and tris (4-isocyanatephenyl) thiophosphate. Is preferred.

In addition, as the biuret body, any of various biuret bodies synthesized by multiplying one or more of the above isocyanates by a biuretization reaction can be used.
The treating agent is prepared by dissolving the above isocyanate or its biuret in an arbitrary organic solvent such as acetone, tetrahydrofuran, ethyl acetate, pyridine and the like. Further, an isocyanate or biuret that is liquid at normal temperature can be used as a treatment agent without being dissolved in an organic solvent.

  Specific examples of the treatment agent include, for example, Desmodur (registered trademark) W (dicyclohexylmethane-4,4′-diisocyanate isomer mixture) manufactured by Covestro Japan Co., Ltd., a 10% acetone solution of the desmodur W, Desmodur N3200 [biuret form of dicyclohexylmethane-4,4′-diisocyanate], desmodur RE [27% ethyl acetate solution of triphenylmethane-4,4 ′, 4 ″ -triisocyanate], desmodur RFE [thiophosphorus 27% ethyl acetate solution of acid tris (4-isocyanate phenyl)], isomer mixture of isophorone diisocyanate [manufactured by Tokyo Chemical Industry Co., Ltd.] and the like.

By applying the treatment agent to the side surface 14 of each divided body 4 by any coating method such as brush coating, spray coating, dip coating, etc., and then allowing to stand at a temperature of about 35 to 45 ° C. for about 2 to 4 hours. Processing is complete.
By performing such treatment, the tensile strength of the joined portion of the divided bodies 4 can be improved as compared with the case where the treatment is not performed.

(First step)
Referring to FIGS. 1 and 2 (a), a temporary fixing pressure-sensitive adhesive sheet 11 having a pressure-sensitive adhesive surface 10 on one side is disposed so that the pressure-sensitive adhesive surface 10 is flat, and the above-mentioned division is performed thereon. In a state where the body 4 is brought close to each other in the surface direction with a strip-shaped spacer 13 having a certain width (for example, about 3 mm) interposed therebetween so that the one surface 12 on the surface resin layer 8 side serving as the plate surface 7 is in contact with the adhesive surface 10. Bond and temporarily fix.

That is, as shown by a broken line in FIG. 1, the divided body 4 is placed on the adhesive surface 10 so that the one surface 12 is in contact with the adhesive surface 10 while the side surface 14 of the divided body 4 is in contact with the side surface 15 of the spacer 13 over the entire length. When the pasting operation is repeated, a plurality of adjacent divided bodies 4 are temporarily fixed on the adhesive surface 10 in a state where the spacers 13 are adjacent to each other across the spacer 13.
2 (a) and 2 (b), on the exposed surface (opposite surface 16) on the reinforcing film 9 side of the plurality of divided bodies 4 temporarily fixed on the adhesive surface 10, the plurality of sheets After sticking one reinforcing sheet 2 over the entire surface of the divided body 4 via the adhesive layer 17 laminated on one side, the adhesive sheet 11 and the spacer 13 for temporary fixing are removed by turning upside down.

The reinforcing sheet 2 is made of the same resin as the reinforcing film 9 having excellent affinity and adhesiveness with the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 17. The reinforcing effect described above and the total thickness of the flexographic printing plate 1 are obtained. Considering this, a sheet having a thickness of about 188 μm to 350 μm is used.
The pressure-sensitive adhesive layer 17 is formed of a photo-curable pressure-sensitive adhesive that is excellent in affinity and pressure-sensitive adhesiveness with the reinforcing sheet 2 and that undergoes a curing reaction upon irradiation with actinic rays together with the above-described photo-curable resin composition. preferable.

As such an adhesive, for example, when the photocurable resin composition has the above-mentioned composition, a compound in which a prepolymer having an ethylenically unsaturated double bond, an ethylenically unsaturated monomer, or the like is blended in the component may be mentioned. It is done.
When the pressure-sensitive adhesive layer 17 made of the pressure-sensitive adhesive is used, the reinforcing sheet 2, the cured product 5 of the photocurable resin composition 19, and the opposite surface 16 of the divided body 4 are irradiated through the pressure-sensitive adhesive layer 17 by irradiation with actinic rays. The reinforcing film 9 constituting the can be joined more firmly.

Therefore, coupled with the fact that the side surface 14 of the divided body 4 is previously treated with the above-mentioned treatment agent, the tensile strength of the joined portion can be further improved.
Any conventionally known general-purpose laminator or the like can be used for laminating the reinforcing sheet 2. In particular, a biaxial drive type pair roll laminator having both upper and lower rolls is most suitable. When such a laminator is used, the deviation in the surface direction of each layer can be minimized.

(Second step)
2B and 3A, after the photocurable resin composition 19 is filled in the gap 18 between the divided bodies 4 from which the spacers 13 are removed, the photocurable resin composition 19 is filled. Is covered with a film 20 such as PE or PP having translucency of actinic rays.
The film 20 may cover the plurality of divided bodies 4 arranged on one side 3 of the reinforcing sheet 2 over the entire surface, or the gap 18 filled with the photocurable resin composition 19 of the divided bodies 4. And only its vicinity may be covered.

(Third process)
Referring to FIGS. 3B and 3C, an actinic ray such as ultraviolet rays is irradiated through the film 20 as shown by solid arrows in the figure, and the photocurable resin composition 19 and the adhesive layer 17 are irradiated. After the pressure-sensitive adhesive forming the curing reaction, the film 20 is peeled off.
Then, as shown in FIG. 3 (c) and FIG. 4, an ink transfer layer 6 is formed in which the adjacent divided bodies 4 are joined together by the cured product 5 of the photocurable resin composition 19, and the ink transfer layer 6 and the reinforcing sheet 2 are firmly adhered to each other through the adhesive layer 17 to produce the plate sheet 1A.

Moreover, since the photo-curing resin composition 19 is cured and covered with the film 20 as described above, the surface of the cured product 5 exposed on the plate surface 7 as shown in FIG. The surface accuracy of the plate surface 7 can be improved by making it flush with the plate surface 7 without requiring a subsequent polishing step or the like.
Moreover, since the tack of the photocurable resin composition 19 can be suppressed by covering with the film 20 and causing the photocurable resin composition 19 to undergo a curing reaction, a cleaning process for wiping off dirt generated by the tack is omitted. You can also.

Thereafter, the reinforcing sheet 2 protruding outside the ink transfer layer 6 is cut from the plate sheet 1A in FIG. 4 to adjust the overall planar shape to a rectangle, and the ink transfer layer 6 in the vicinity of two sides parallel to each other is formed. , for example, the grip portion 61 by laser machining or the like, to form a groove 62 and the pin hole 63, to form a predetermined pattern P ₁₁ to P _xy further plate surface 7, the flexographic printing plate shown in FIG. 5 is completed.

As described above, the flexographic printing plate 1 manufactured through the respective steps of the first embodiment is selected in advance from the group consisting of isocyanate and its biuret body as the side surface 14 of the divided body 4 as a base. In addition, since it is treated with a treating agent containing at least one kind, it has excellent tensile strength at the joined portion.
Therefore, according to the flexographic printing plate 1, it can sufficiently withstand the tensile stress repeatedly applied particularly when continuously printing a liquid crystal alignment film or the like of a large liquid crystal display element, and from a joined portion at a relatively early stage. It is possible to continue printing up to a preset number of prints without tearing or peeling.

Moreover, according to the flexographic printing plate 1, as described above, the patterns P _{11 to} P are later formed on the plate surface 7 of the ink transfer layer 6 formed by integrally joining the divided bodies 4 that are not patterned. _{Since xy} is formed, for example, the accuracy of the pattern position can be greatly improved by setting both the accuracy in the x direction and the y direction on the plate surface 7 to about ± 100 μm.
<Second embodiment>
In the second embodiment of the present invention, the divided body 4 that is patterned in advance is used. Other steps are the same as in the first embodiment.

That is, in FIG. 6, a part of the surface of the surface layer resin layer 8 that becomes the plate surface 7 of each divided body 4 that is a laminate of the surface layer resin layer 8 and the reinforcing film 9 constituting the plate surface 7 is omitted. As described above, predetermined patterns P _{11 to} P _xy corresponding to x × y print patterns are formed first.
Further, at any time before or after that, the side surface 14 of each of the divided bodies 4 to be joined to the other divided bodies 4 is degreased with an organic solvent such as acetone or tetrahydrofuran as necessary, and then dried. And a treatment agent containing at least one selected from the group consisting of the biuret bodies.

Next, similarly to the first embodiment, the plate sheet 1B shown in FIG. 6 is produced through the steps of FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) to 3 (c).
Thereafter, the reinforcing sheet 2 that protrudes outside the ink transfer layer 6 is cut from the plate sheet 1B to adjust the overall planar shape to a rectangle, and the ink transfer layer 6 in the vicinity of the two sides parallel to each other is, for example, a laser. When the gripping part 61, the groove part 62 and the pin hole 63 are formed by processing or the like, the flexographic printing plate shown in FIG. 5 is completed.

Also in the flexographic printing plate 1 manufactured through the steps of the second embodiment, the side surface 14 of the divided body 4 that is the basis of the flexographic printing plate 1 is treated in advance with the treatment agent. Are better.
Therefore, according to the flexographic printing plate 1, it can sufficiently withstand the tensile stress repeatedly applied when continuously printing a liquid crystal alignment film or the like of a large liquid crystal display element, and from a joined portion at a relatively early stage. It is possible to continue printing up to a preset number of prints without tearing or peeling.

Moreover, according to the flexographic printing plate 1, the overall positional accuracy of the flexographic printing plate 1 is manufactured in the first embodiment by increasing the dimensional accuracy in the surface direction of the divided body and the accuracy of the spacer thickness, for example. Can be maintained at the same high level as
<< Method for manufacturing liquid crystal display element >>
This invention is a manufacturing method of the liquid crystal display element including the process of forming a liquid crystal aligning film by flexographic printing using the flexographic printing plate manufactured by the manufacturing method of the said invention.

According to the present invention, by using a flexographic printing plate produced by the above production method and excellent in overall thickness accuracy, the plate surface of the flexographic printing plate can be used for miniaturization of irregularities on the surface of the substrate. Therefore, the liquid crystal display element including the liquid crystal alignment film having a uniform thickness and no pinhole can be manufactured.
Other steps of the production method of the present invention can be carried out in the same manner as in the prior art.

That is, a transparent electrode layer corresponding to a predetermined matrix pattern or the like is formed on the surface of a transparent substrate such as a glass substrate, and a liquid crystal alignment film is formed by flexographic printing using the flexographic printing plate. The substrate is prepared by subjecting the surface to orientation treatment by rubbing or the like as necessary.
Two substrates are prepared, and with the respective transparent electrode layers aligned, a liquid crystal material is sandwiched between them and fixed together to form a laminated body. Further, if necessary, both outer sides of the laminated body A liquid crystal display element is manufactured by disposing a polarizing plate.

The configuration of the present invention is not limited to the example of the figure described above.
For example, the divided body 4 constituting the ink transfer layer 6 may be two or three, or may be five or more.
Each divided body 4 may not be the same shape and the same size, but may be formed in a different shape and size depending on which position of the ink transfer layer 6 is formed. However, in consideration of saving the time and labor of the combination, it is preferable to use a combination of two or more divided bodies 4 having the same shape and the same size.

In the example shown in the figure, the side surface 14 of the divided body 4 is a vertical surface orthogonal to the one surface 12 that becomes the plate surface 7, but the opposite surface 16 side protrudes from the one surface 12 rather than the one surface 12 side. It is also possible to use an inclined surface inclined at a predetermined inclination angle.
In this case, the gap 18 between the adjacent divided bodies 4 is formed in an inverted trapezoidal shape with a wide opening on the plate surface 7 side, so that the photocurable resin composition 19 can be easily injected and the entrapment of bubbles can be suppressed. .

Therefore, the side surface 14 is previously treated with a treatment agent containing at least one selected from the group consisting of isocyanate and its biuret body, and the side surface 14 and the cured product 5 of the photocurable resin composition 19 Combined with the fact that the contact area can be increased, the tensile strength of the joined portion can be further improved.
In addition, various design changes can be made without departing from the scope of the present invention.

<Example 1>
(Preparation of divided body 4)
As the photocurable resin composition that is the basis of the surface resin layer 8, a urethane prepolymer having an 1,2-butadiene structure and having an ethylenically unsaturated double bond at the terminal, an ethylenically unsaturated monomer, And a composition [NK resin manufactured by Sumitomo Rubber Industries, Ltd.] containing a photopolymerization initiator.

The photocurable resin composition is sandwiched between the mold surface and the reinforcing film 9 made of PET and irradiated with ultraviolet rays having a wavelength of 365 nm for 15 minutes to cure and cure the photocurable resin composition. A sample of the divided body 4 was cut out to 150 mm.
The total thickness of the divided body 4 was 2.56 mm.
(Manufacture of flexographic printing plate 1)
In an environment of a temperature of 23 ° C. and a relative humidity of 55%, the side surface 14 of the divided body 4 is first degreased with acetone and dried for 1 hour, and then desmodule W [dicyclohexylmethane − manufactured by Covestro Japan Co., Ltd. The isomer mixture of 4,4'-diisocyanate] was applied with a brush and allowed to stand at 40 ° C for 3 hours.

Then, according to the procedure described above, the four divided bodies 4 were joined as shown in FIGS. 1 to 4 to form the ink transfer layer 6.
That is, as the photocurable resin composition 19 for joining the divided bodies 4, the same composition as above (NK resin manufactured by Sumitomo Rubber Industries, Ltd.) was used. The reinforcing sheet 2 is made of PET and has a pressure-sensitive adhesive layer 17 laminated on one side.

In a state where the photocurable resin composition 19 is filled in the gap 18 and covered with the PP film 20, ultraviolet light having a wavelength of 365 nm is irradiated for 15 minutes to cause a curing reaction, and the adjacent divided bodies 4 are separated from each other by the light. The ink transfer layer 6 was formed by bonding with the cured product 5 of the curable resin composition 19.
Then, patterns P _{11 to} P _xy corresponding to x × y printing patterns were formed on the plate surface 7 of the formed ink transfer layer 6 to produce a flexographic printing plate shown in FIG.

<Example 2>
In an environment of a temperature of 23 ° C. and a relative humidity of 55%, the side surface 14 of the divided body 4 is first degreased with acetone and dried for 1 hour, and then the same des module manufactured by Covestro Japan Co., Ltd. used in Example 1. A flexographic printing plate was produced in the same manner as in Example 1 except that it was immersed in a 10% acetone solution of W for 15 seconds, then lifted and allowed to stand at 40 ° C. for 3 hours.

<Example 3>
In an environment of a temperature of 23 ° C. and a relative humidity of 55%, the side surface 14 of the divided body 4 is first degreased with acetone and dried for 1 hour, and then desmod N3200 [dicyclohexylmethane-4 manufactured by Covestro Japan Co., Ltd.] , 4'-diisocyanate biuret] was prepared in the same manner as in Example 1 except that it was allowed to stand at 40 ° C for 3 hours.

<Example 4>
In an environment of a temperature of 23 ° C. and a relative humidity of 55%, the side surface 14 of the divided body 4 is first degreased with acetone and dried for 1 hour, and then the isophorone diisocyanate isomer mixture (manufactured by Tokyo Chemical Industry Co., Ltd.) is used. A flexographic printing plate was produced in the same manner as in Example 1 except that it was brushed and then allowed to stand at 40 ° C. for 3 hours.

<Example 5>
In an environment of a temperature of 23 ° C. and a relative humidity of 55%, the side surface 14 of the divided body 4 is first degreased with acetone and dried for 1 hour, and then desmod RE [triphenylmethane- A flexographic printing plate was produced in the same manner as in Example 1 except that 27% ethyl acetate solution of 4,4 ′, 4 ″ -triisocyanate was brushed and left to stand at 40 ° C. for 3 hours.

<Example 6>
In an environment of a temperature of 23 ° C. and a relative humidity of 55%, the side surface 14 of the divided body 4 is first degreased with acetone and dried for 1 hour, and then desmodule RFE [Tris thiophosphate] manufactured by Covestro Japan Co., Ltd. A flexographic printing plate was produced in the same manner as in Example 1 except that it was dipped in a 27% ethyl acetate solution of (4-isocyanatophenyl) for 15 seconds, then pulled up and allowed to stand at 40 ° C. for 3 hours.

<Comparative example 1>
In an environment of a temperature of 23 ° C. and a relative humidity of 55%, the side surface 14 of the divided body 4 is first degreased with acetone and dried for 1 hour, and then a commercially available cyanoacrylate adhesive [Aron Alpha (registered trademark) manufactured by Toagosei Co., Ltd. A flexographic printing plate was produced in the same manner as in Example 1 except that the coating was applied in direct contact immediately after opening and dried for 3 hours. This is a reproduction of the joining described in Patent Document 1.

<Comparative example 2>
A flexographic printing plate was prepared in the same manner as in Example 1 except that the side surface 14 of the divided body 4 was degreased with acetone and dried for 3 hours in an environment of a temperature of 23 ° C. and a relative humidity of 55%, and then used as it was. Manufactured.
<Tensile property test>
The flexographic printing plates produced in Examples 1 to 6 and Comparative Examples 1 and 2 were cured for 18 hours under an environment of a temperature of 23 ° C. and a relative humidity of 55%, and then the reinforcing film was peeled off using a ham slicer to a thickness of 2 mm. After adjustment, the shape of the dumbbell-shaped No. 3 test piece specified in Japanese Industrial Standard JIS K6251: 2010 “Vulcanized rubber and thermoplastic rubber – Determination of tensile properties”, and so as to cross the parallel part A test piece was punched out so that the joint between the divided bodies 4 was located.

And tensile strength TS (MPa) and elongation at break _Eb (%) were determined from the results of measurement according to the measurement method described in the above standard.
<Real machine test>
In an environment of a temperature of 23 ° C. and a relative humidity of 55%, the flexographic printing plates produced in Examples 1 to 6 and Comparative Examples 1 and 2 were set on the plate cylinder of a flexographic printing machine and continuously printed 20000 times. The state of the flexographic printing plate at that time was recorded.

The above results are shown in Tables 1 and 2. In the table, the symbols in the “side treatment” column are as follows.
HDI: Desmodur W [isomer mixture of dicyclohexylmethane-4,4′-diisocyanate]
HDIbu: Desmodur N3200 [biuret of dicyclohexylmethane-4,4′-diisocyanate]
IDI: Isophorone diisocyanate isomer mixture [manufactured by Tokyo Chemical Industry Co., Ltd.]
TTI: Desmodur RE [27% ethyl acetate solution of triphenylmethane-4,4 ′, 4 ″ -triisocyanate]
TPI: Desmodur RFE [27% ethyl acetate solution of tris (4-isocyanatophenyl) thiophosphate]

  From the results of Examples 1 to 6 and Comparative Examples 1 and 2 in Tables 1 and 2, the side surface 14 of the divided body 4 is treated with a treatment agent containing at least one selected from the group consisting of isocyanate and its biuret body in advance. By treating, not only the case of not treating but also the case of treating with cyanoacrylate described in Patent Document 1, the tensile strength of the joined portion between the divided bodies 4 can be improved, and a predetermined number of printed sheets can be obtained. In the meantime, it has been found that a flexographic printing plate that is not torn off or peeled off from the joined portion can be produced.

DESCRIPTION OF SYMBOLS 1 Flexo printing plate 1A, 1B Plate sheet 2 Reinforcement sheet 3 Single side 4 Divided body 5 Hardened material 6 Ink transfer layer 7 Plate surface 8 Surface layer resin layer 9 Reinforcement film 10 Adhesive surface 11 Adhesive sheet 12 Single side 13 Spacer 14 Side 15 Side 16 Opposite Surface 17 Adhesive layer 18 Gap 19 Photocurable resin composition 20 Film 61 Holding portion 62 Groove portion 63 Pin hole P ₁₁ -P _xy pattern

Claims (4)

A method for producing a flexographic printing plate having a resin ink transfer layer,
A step of arranging a plurality of sheet-like divided bodies on which the ink transfer layer is based on the same plane at regular intervals in the surface direction;
Filling the gaps between the arrayed divided bodies with a photocurable resin composition that undergoes a curing reaction by irradiation with actinic rays, and curing reaction of the photocurable resin composition by irradiation with actinic rays And forming the ink transfer layer by joining the plurality of divided bodies to each other, and the side surfaces of the divided bodies to be joined to the other divided bodies are made of an isocyanate and its biuret body in advance. The manufacturing method of a flexographic printing plate which also includes the process processed with the processing agent containing at least 1 sort (s) chosen from more.   The treating agent includes dicyclohexylmethane-4,4′-diisocyanate, isophorone diisocyanate, triphenylmethane-4,4 ′, 4 ″ -triisocyanate, tris (4-isocyanatephenyl) thiophosphate, and biurets thereof. The flexographic printing plate according to claim 1, wherein the flexographic printing plate is a liquid processing agent containing at least one selected from the group consisting of the processing agent, which is applied to the side surface and then left to stand for a predetermined time at a predetermined temperature. Production method.   The method for producing a flexographic printing plate according to claim 1, wherein the photocurable resin composition is a composition containing a urethane prepolymer.   The manufacturing method of a liquid crystal display element including the process of forming a liquid crystal aligning film by flexographic printing using the flexographic printing plate manufactured by the manufacturing method of any one of the said Claim 1 thru | or 3.

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