JP2017019142A - Flexographic printing plate, method for producing the same, and method for producing a liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexographic printing plate and a method for manufacturing the flexographic printing plate that less likely induces ink accumulation and squeeze-out and blurring of a printed pattern associated with the ink accumulation when printing is repeated, and a method for manufacturing a liquid crystal display element using the flexographic printing plate.SOLUTION: A flexographic printing plate 1 is configured in such a manner that a recessed part 7 corresponding to a non-printing region of a print pattern is formed on a printing surface 2 and that the printing surface exhibits a contact angle with N-methyl-2-pyrrolidone to be smaller by 5° or more than that of an inner surface of the recessed part. The method for manufacturing the flexographic printing plate includes steps of successively stacking a surface resin layer that forms the printing surface and a photosensitive resin composition that gives a support resin layer forming the inner surface of the recessed part, and irradiating the layers with active rays to form resin layers. The method for manufacturing a liquid crystal display element includes a step of forming a liquid crystal alignment film by using the above flexographic printing plate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flexographic printing plate, a method for producing the flexographic printing plate, and a method for producing a liquid crystal display element using the flexographic printing plate.

For example, in the case of TFT liquid crystal, flexographic printing is employed to form a liquid crystal alignment film on the TFT circuit formation surface and the color filter formation surface of the pair of substrates.
Since flexographic printing has good printing characteristics, it is required to have a high coating quality such that the surface to be printed such as the TFT circuit forming surface and the color filter forming surface is as uniform as possible, has no pinholes, and is thin. It is suitable for forming a liquid crystal alignment film.

In flexographic printing, a flexible resin sheet is used. One side of the flexographic printing is brought into contact with the surface to be printed while holding the ink used as the liquid crystal alignment film, etc., and the retained ink is transferred to the surface to be printed. A flexographic printing plate having a surface to be printed, that is, a printing surface is used.
The printing surface of the flexographic printing plate is formed in the printing area of the printing pattern by removing the area corresponding to the non-printing area of the printing pattern to a predetermined depth by thermal processing such as laser engraving or mechanical processing. A pattern is formed in a corresponding planar shape.

In addition, in order to improve the affinity (ink affinity) for the ink on the patterned printed surface so that the ink can be held well, and the held ink can be transferred to the printed surface well. In general, an arbitrary uneven surface such as a rough surface is used.
Various studies have been made on the shape, structure, formation method, and the like of the uneven surface (Patent Documents 1 to 3, etc.).

In recent years, with the narrowing of the liquid crystal screen (reduction in the blank area) in small liquid crystal display elements, particularly for smartphones, the TTF circuit side and the color filter side are very strict regarding the positional accuracy of the liquid crystal alignment film printing. Requests are coming. Particularly recently, severe position control of ± 0.6 mm has been required.
Therefore, various studies have been made on increasing the positional accuracy of pattern formation on the printing surface as much as possible and making the flexographic printing plate difficult to be displaced during printing (Patent Document 4 and the like).

However, when printing is repeated using a conventional flexographic printing plate, the ink retained on the printing surface is squeezed by the nip at the time of printing, and is pushed backward on the patterned printing surface in the printing progress direction. As a result, it finally flows from the edge of the printing surface into a recess that forms a non-printing area, and an ink pool tends to be generated in the recess.
Further, there is a problem in that the generated ink reservoir causes the printing pattern to protrude or bleed, resulting in a decrease in printing accuracy.

  Alternatively, when the liquid crystal display element is produced, when the liquid crystal display element is produced, the sealing material that surrounds and encloses the liquid crystal material sandwiched between the pair of substrates and fixes the pair of substrates to each other is prevented. There is also a possibility that the strength of the seal may be reduced by overlapping on the dipped ink, and the performance and life of the liquid crystal display element may be reduced.

JP 2002-293049 A Japanese Patent No. 2933790 JP 2009-34913 A Japanese Patent No. 5702006

  An object of the present invention is to provide a flexographic printing plate that is less likely to cause ink stagnation and accompanying printing pattern bleeding or bleeding when printing is repeated, and a method for producing the same, and a method for producing a liquid crystal display element using the flexographic printing plate Is to provide.

In the present invention, one side is a printing surface, and the printing surface includes an ink transfer layer in which a concave portion corresponding to a non-printing region of a predetermined printing pattern is formed, and the printing surface is N from the inner surface of the concave portion. -A flexographic printing plate having a contact angle of methyl-2-pyrrolidone of 5 ° or less.
The ink transfer layer includes a support resin layer and a surface resin layer that is laminated on the support resin layer to form the printing surface, and the surface resin layer is N more than a resin that forms the support resin layer. -A layer having a thickness of 0.02 mm or more and 0.4 mm or less made of a resin having a small contact angle of methyl-2-pyrrolidone, and the concave portion is formed so as to reach the support resin layer from the printing surface. At the same time, it is preferable that the contact angle of the N-methyl-2-pyrrolidone is 5 ° or less smaller than the inner surface of the recess.

  In the present invention, a photosensitive resin composition that is the basis of the surface resin layer is coated on the uneven surface of the mold, and the photosensitive resin composition that is the basis of the support resin layer is laminated thereon. In this state, the photosensitive resin composition is cured by irradiation with actinic rays to form a laminate of the two resin layers, the formed laminate is peeled from the mold surface, and the surface layer is formed. A step of making a surface of the resin layer in contact with the mold surface a printed surface having an uneven surface, and thermally or mechanically cutting off the resin in the non-printing area of the printed surface having an uneven surface And it is a manufacturing method of a flexographic printing plate including the process of forming the said recessed part which reaches the said support resin layer.

  Furthermore, 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 said flexographic printing plate.

  According to the present invention, when printing is repeated, a flexographic printing plate which is less likely to cause ink stagnation and accompanying printing pattern bleeding and bleeding, a method for producing the same, and a method for producing a liquid crystal display element using the flexographic printing plate Can provide.

Fig. (A) is a perspective view showing an example of an embodiment of the flexographic printing plate of the present invention, and Fig. (B) is an enlarged sectional view showing a part of the flexographic printing plate of the above example. FIGS. 2A and 2B are cross-sectional views showing the steps of an example of the embodiment of the manufacturing method of the present invention. FIGS. (A) and (b) are cross-sectional views showing subsequent steps of the manufacturing method of the above example. FIGS. 4A to 4C are cross-sectional views showing further steps of the manufacturing method of the above example.

<Flexographic printing plate>
The flexographic printing plate of the present invention has one surface as a printing surface, and the printing surface includes an ink transfer layer in which a concave portion corresponding to a non-printing region of a predetermined printing pattern is formed, and the printing surface includes the concave portion The contact angle of N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as “NMP”) is smaller by 5 ° or more than the inner surface of.

  According to such a flexographic printing plate of the present invention, the contact angle of NMP as a representative example of the solvent for ink is made oleophilic (ink oleophilic) smaller than the inner surface of the recess by 5 ° or more on the printing surface as described above. By making the inner surface of the recess relatively oil-repellent (ink-repellent) from the printing surface, coupled with the surface tension of the ink itself, the ink is kept on the printing surface as much as possible, or the ink that has flowed into the recess from the edge It can be pulled back onto the printed surface.

For this reason, it is possible to suppress the ink from flowing into the recesses and to prevent the ink pool from being generated, or to reduce the generated ink pool as much as possible, and to prevent the printing pattern from protruding or bleeding due to the ink pool.
In order to change the contact angle of NMP between the printing surface and the inner surface of the recess, for example, the inner surface of the recess is chemically treated with silicone or a silane coupling agent, or physically treated with fluorine plasma, etc. It is conceivable to increase the contact angle of the ink by 5 ° or more from the printed surface.

Conversely, it is also conceivable to make the contact angle of the print surface 5 ° or more smaller than the inner surface by subjecting the print surface to frame treatment, corona discharge treatment, ultraviolet irradiation treatment, or the like.
However, since these processes are processes for only the surface layer portion of each surface, the effects of the above processes may be reduced or lost in a relatively short period of time while flexographic printing is repeated.

That is, when printing is repeated, the effect of the processing is rapidly lost, and the difference in the contact angle of NMP between both surfaces is rapidly reduced, so that the above-described effect may not be obtained in a relatively short period of time.
In order to maintain the difference in the contact angle of NMP for as long as possible, it is preferable to employ, for example, the structure shown in FIGS.
FIG. 1A is a perspective view showing an example of an embodiment of a flexographic printing plate of the present invention, and FIG. 1B is an enlarged sectional view showing a part of the flexographic printing plate of the above example. .

With reference to both figures, the flexographic printing plate 1 of this example is formed in the shape of a rectangular flat plate as a whole, the ink transfer layer 3 having one side (upper surface in the figure) as the printing surface 2, and the ink transfer And a reinforcing sheet 4 laminated on the opposite surface of the layer 3.
The ink transfer layer 3 is composed of a two-layer laminate of a support resin layer 5 directly laminated with the reinforcing sheet 4 and a surface resin layer 6 laminated on the support resin layer 5 and constituting the printing surface 2. Become.

On the printing surface 2, a lattice-shaped recess 7 corresponding to a non-printing region of a predetermined printing pattern is formed so as to reach the supporting resin layer 5 from the printing surface 2, whereby the printing surface 2 is A pattern is formed corresponding to the print pattern, and the support resin layer 5 is exposed on the inner surface 8 of the recess 7.
Further, when the flexographic printing plate 1 is set on the flexographic printing machine in the vicinity of the two parallel sides of the rectangle of the flexographic printing plate 1 and on the outside of the printing surface 2, the flexographic printing plate 1 is gripped by a vise (not shown). For this purpose, a gripping portion 11 made up of the ridge portion 9 and the groove 10 is provided over the entire width of each side.

Further, the protruding portion 9 is provided with a holding pin 11 (not shown) in a state where the holding portion 11 is held and held by a vice at equal intervals at a plurality of locations in the length direction (5 locations in the figure). A chuck hole 12 is formed for inserting and fixing.
The surface resin layer 6 is formed of a resin having a smaller contact angle of NMP than that of the resin forming the support resin layer 5.

Moreover, the printing surface 2 which is the exposed surface of the surface resin layer 6 is a rough surface as an uneven surface that can make the contact angle of NMP smaller than a smooth surface, as in the conventional case.
Then, based on the material characteristics of the resin itself and the shape characteristics of the printing surface 2, the printing surface 2 is brought into contact with the NMP from the inner surface 8 of the recess 7 which is the exposed surface of the support resin layer 5. Is made oleophilic smaller by 5 ° or more, and the inner surface 8 is relatively more oleophobic than the printing surface 2.

  Therefore, according to the flexographic printing plate 1 of the example shown in the drawing, the ink is kept on the printing surface 2 as much as possible, or the ink that has flowed from the edge into the recess 7 is pulled back onto the printing surface 2, so Can be suppressed, and when printing is repeated, it is possible to suppress the occurrence of an ink pool in the concave portion 7 or to reduce the generated ink pool as much as possible. Bleeding or the like can be made difficult to occur.

In addition, since the entire surface resin layer 6 and the support resin layer 5 are each made of the same resin, even if printing is repeated, the above-mentioned rough surface can be maintained, that is, about the same level as in the case of a normal flexographic printing plate The difference in the contact angle of the NMP described above can be maintained over the period.
Therefore, according to the flexographic printing plate 1 of the example shown in the drawing, it is possible to maintain the effect of making it difficult to cause ink stagnation and the accompanying printing pattern to bleed out and bleed as described above. .

The thickness of the surface resin layer 6 needs to be 0.02 mm or more and 0.4 mm or less, and particularly preferably 0.2 mm or less.
It is not easy to form a thin surface resin layer 6 having a thickness less than this range, and even if it can be formed, the surface resin layer 6 is too thin and insufficient in durability. There is a risk that the above-described effects due to the two-layer structure of the ink transfer layer 3 become insufficient due to wear and loss in a short period of time.

On the other hand, when the thickness of the surface resin layer 6 exceeds the above range, the lipophilic resin forming the surface resin layer 6 is exposed thickly in the vicinity of the opening in the inner surface 8 of the recess 7. The inflow of ink is promoted, and there is a possibility that an ink reservoir is likely to occur in the recess 7.
On the other hand, by making the thickness of the surface resin layer 6 in the above range, the surface resin layer 6 is disposed in the vicinity of the opening in the inner surface 8 of the recess 7 while maintaining good durability of the surface resin layer 6. It can suppress that the lipophilic resin to form forms a thick exposure and causes ink stagnation.

The difference in the contact angle of NMP between the printing surface 2 and the inner surface 8 of the recess 7 is preferably as large as possible even in the above-described range of 5 ° or more, and particularly preferably 10 ° or more.
In order to increase the difference in the contact angle of NMP between the two surfaces 2 and 8, the shape of the uneven surface such as the rough surface provided on the printing surface 2 is changed, or the resin and the supporting resin layer that form the surface resin layer 6 The difference in the contact angle of NMP of the resin that forms 5 may be increased.

However, there is a limit to the range in which the contact angle of NMP can be adjusted by changing the shape of the concavo-convex surface. To further increase the difference in contact angle of NMP, resin with a large difference in contact angle is selected and combined. Is preferred.
However, it is not easy to form the ink transfer layer 3 by integrally laminating two layers made of a resin having a too large difference in contact angle, and there is a possibility that peeling or the like is likely to occur between layers due to stress during printing.

Therefore, in consideration of improving the integrity of the ink transfer layer 3, it is not preferable to increase the difference in NMP contact angle between the resins forming the layers 5 and 6 as a result. The difference in the contact angle of NMP between 2 and the inner surface 8 of the recess 7 is preferably 30 ° or less even in the above range.
In order to change the NMP contact angle between the resin that forms the surface resin layer 6 and the resin that forms the support resin layer 5, the composition of the resin that forms the two layers may be different.

  For example, a prepolymer having a 1,2-butadiene structure and having an ethylenically unsaturated double bond at the terminal, used as a material for forming both layers in the production method of the present invention described later, an ethylenically unsaturated monomer In the case of the photosensitive resin composition containing the body and the photopolymerization initiator, the resin that forms the surface resin layer 6 and the supporting resin layer 5 by changing the type and blending ratio of each component for each layer, that is, The contact angle of NMP of the cured product of each photosensitive resin composition can be changed.

The specific range of the difference in the contact angle of NMP between the resins forming both layers 5 and 6 is not particularly limited.
For example, when the printing surface 2 is a rough surface such as a rough surface as shown in the figure, the difference between the contact angles of the NMPs on both surfaces 2 and 8 together with the decrease in the contact angle due to the uneven surface is 5 as described above. What is necessary is just to make a difference in the contact angle of both resin so that it may become the range more than °.

In the present invention, the contact angle of NMP was dropped in a 2 μl drop volume of NMP using a measuring instrument FTA125 manufactured by First Ten Angstroms in a standard atmosphere at a temperature of 23 ± 2 ° C. and a relative humidity of 50 ± 2%. The average value of n = 5 of the measured values of the droplet slope angle after 5 seconds is represented.
For example, the contact angle between the printing surface 2 and the surface 8 of the recess 7 is a value obtained by directly measuring the printing surface 2 and the surface 8 of the recess 7 of the manufactured flexographic printing plate 1. On the other hand, the contact angle of the resin that forms the surface resin layer 6 and the support resin layer 5 is a value measured on a measurement surface that is finished smoothly in order to eliminate the influence of shape.

The shape, structure, formation method, and the like of the concavo-convex surface imparted to the printing surface 2 of the surface resin layer 6 may be the same as those in the past.
However, as described above, the difference between the contact angles of the NMPs on both surfaces 2 and 8 of the resins forming the both layers 5 and 6 is within the range of 5 ° or more as described above. It is preferable to adjust the shape, structure and the like of the uneven surface to be formed.

In the present invention, it is also conceivable that the printing surface 2 is not a rough surface but a smooth surface. In that case, the contact angle of NMP on the printing surface 2 is equivalent to the contact angle of the resin forming the surface resin layer 6.
Therefore, when the printing surface 2 is a smooth surface, the difference in contact angle between the resins forming the surface resin layer 6 and the support resin layer 5 is preferably 5 ° or more, and preferably 30 ° or less. .

The thickness of the support resin layer 5 can be set arbitrarily.
In particular, the thickness of the support resin layer 5 is such that the thickness of the ink transfer layer 3 composed of two layers, the support resin layer 5 and the surface resin layer 6, is approximately the same as the thickness of the conventional single-layer ink transfer layer 3. May be adjusted according to the thickness of the surface resin layer 6.
Specifically, the thickness of the support resin layer 5 is preferably 2 mm or more, and preferably 2.4 mm or less.

If the recessed part 7 has reached the support resin layer 5, the depth can be set arbitrarily. For example, depending on the thickness of the surface resin layer 6, only the surface resin layer 6 may be removed to expose the surface of the support resin layer 5.
However, even if ink flows into the concave portion 7 to cause an ink pool, the concave portion 7 is formed as a support resin layer as shown in FIG. 5 is preferably formed to a depth reaching the inside.

Specifically, the depth of the recess 7 is preferably 0.4 mm or more and less than the thickness of the ink transfer layer 3.
The reinforcing sheet 4 may be omitted. However, by laminating the reinforcing sheet 4, the tensile strength of the flexographic printing plate 1 can be improved, or the expansion and contraction in the surface direction of the flexographic printing plate 1 can be suppressed, and the printing surface 2. The dimensional accuracy of the pattern can be improved.

Examples of the reinforcing sheet 4 include thermoplastic resins such as polyethylene (PE), polypropylene (PP), thermoplastic polyurethane elastomer (TPU), polyethylene terephthalate (PET), and tetrafluoroethylene / hexafluoropropylene copolymer (FEP). A sheet, a metal sheet, or a laminate sheet of both can be used.
Further, when the manufacturing method described below is adopted and the active sheet such as ultraviolet rays is irradiated also from the reinforcing sheet 4 side, the reinforcing sheet 4 is a sheet made of the thermoplastic resin and having transparency to the active light. Can be used.

<Manufacturing method of flexographic printing plate>
2 (a) and 2 (b) are cross-sectional views showing the steps of an example of the embodiment of the manufacturing method of the present invention. 3 (a) and 3 (b) are cross-sectional views showing the subsequent steps of the manufacturing method of the above example. Further, FIGS. 4A to 4C are cross-sectional views showing further steps of the manufacturing method of the above example.
Referring to FIG. 2 (a), in the manufacturing method of this example, it is hard and has transparency to actinic rays such as ultraviolet rays such as glass or hard resins such as acrylic resin, polycarbonate resin, and polyester resin. A support substrate 13 made of a material and a counter substrate 14 to be paired are prepared.

The counter substrate 14 is formed of any material such as glass, hard resin, or metal. When irradiating active light from the counter substrate 14 side, the counter substrate 14 may be formed of glass or hard resin having the same transmissivity to active light as the support substrate 13.
The support substrate 13 and the counter substrate 14 are arranged with the support surface 15 of the support substrate 13 and the counter surface 16 of the counter substrate 14 facing each other in parallel.

Below the support substrate 13, a plurality of UV lamps 17, which are ultraviolet light sources as actinic rays, are arranged at equal intervals.
In addition, in order to make the printing surface 2 of the surface resin layer 6 a rough surface as an uneven surface, a roughened sheet 19 having a mold surface 18 whose one side (upper surface in the figure) is roughened is prepared.
The roughened sheet 19 is made of a thermoplastic resin such as PE, PP, TPU, PET, FEP, and the like, and one side of the sheet having transparency to actinic rays is used, for example, pressure sheet molding using an embossing roll, etc. It is preferable to use a surface roughened by.

According to such pressure sheet molding, there is an advantage that it is easy to produce the roughened sheet 19 continuously and in large quantities.
Of the above, the roughened sheet 19 made of a relatively soft thermoplastic resin such as PE, PP, TPU, etc. and relatively thin (for example, about 150 μm or less) is weak in itself and has a flat support. In some cases, it is difficult to make the support surface 15 of the substrate 13 adhere uniformly without wrinkles.

In that case, a reinforcing sheet made of, for example, PET and having transparency to actinic rays may be bonded to the opposite surface of the roughened sheet 19.
The roughened sheet 19 is stacked on the support surface 15 of the support substrate 13 in order from one end to the other end, as indicated by a dashed line arrow in FIG. Then, detachably fix.

  The roughened sheet 19 is applied to the support substrate 13 by a shearing force when the liquid photosensitive resin composition is spread on the roughened sheet 19 or a shrinkage force when the photosensitive resin composition is cured. In order to prevent displacement from occurring and facilitate replacement of the roughened sheet 19 after use, the support surface 15 of the support substrate 13 is formed by, for example, any one of the following methods (i) to (iii). It is preferable to detachably fix to.

(i) Removably adhesively fixed to the support surface 15 through a weak adhesive layer made of a material having transparency to actinic rays.
(ii) A suction groove is formed on the support surface 15, and vacuum suction is performed through the suction groove, so that the support surface 15 is detachably attached to the support surface 15.
(iii) Removably press-fixed to the support surface 15 in a state of being stretched between a pair of chuck jigs spaced apart from the dimension in the surface direction of the support substrate 13.

  Among these, as the weak adhesive layer (i) used for adhesive fixation, various adhesives having weak adhesiveness to the forming material of the support substrate 13 and the roughened sheet 19 and having transparency to actinic rays. Any of these layers can be used. The weak adhesive layer is coated with an adhesive on at least one of the support surface 15 of the support substrate 13 and the opposite surface (lower surface in the drawing) of the roughened sheet 19 by various coating methods such as spray coating. Is formed.

  After forming such a weak adhesive layer on the support surface 15 of the support substrate 13 and / or the opposite surface of the roughened sheet 19, as shown by the dashed line arrow in FIG. When the mold surface 18 is placed on the support surface 15 in order so that air does not enter between the one end and the other end, the roughened sheet 19 is adhered to the weak adhesive layer. It can be fixed to the support surface 15 by force.

Further, in order to remove the fixed roughened sheet 19 from the support surface 15, the roughened sheet 19 is weakened from the other end of the support substrate 13 to one end, for example, contrary to the arrow in FIG. What is necessary is just to peel in order, resisting the adhesive force of an adhesion layer.
In order to perform the suction fixation of (ii), the support surface 15 of the support substrate 13 is finished smoothly, and suction grooves are formed on substantially the entire support surface 15. The suction groove is connected to a vacuum system including a vacuum pump or the like.

Then, with the roughened sheet 19 placed on the support surface 15 of the support substrate 13 with the mold surface 18 facing upward, the vacuum system is operated or the previously operated vacuum system is connected to the suction groove. For example, the roughened sheet 19 can be fixed to the support surface 15 by vacuum suction of the roughened sheet 19 through the suction groove.
In order to remove the fixed roughened sheet 19 from the support surface 15, the vacuum system may be stopped or the connection between the vacuum system and the suction groove may be interrupted.

  Referring to FIG. 2 (b), a liquid that forms the surface resin layer 6 is formed on the mold surface 18 of the roughened sheet 19 fixed to the support surface 15 of the support substrate 13 by any of the above methods. The photosensitive resin composition 20 is supplied and, for example, using a blade 21, a predetermined thickness is obtained from one end to the other end of the support surface 15 of the support substrate 13 as indicated by a dashed line arrow in the drawing. The first precursor layer 22 made of the photosensitive resin composition 20 and serving as the basis of the surface resin layer 6 is formed by spreading the film on the surface.

  Referring to FIG. 3 (a), a liquid photosensitive resin composition 23 that is the basis of the supporting resin layer 5 is supplied onto the formed first precursor layer 22, and, for example, using a blade 24, As shown by the dashed-dotted arrow, the support resin layer 23 is made of the photosensitive resin composition 23 by spreading from one end to the other end of the support surface 15 of the support substrate 13 so as to have a predetermined thickness. 5 is formed.

At substantially the same time, the reinforcing sheet 4 is formed from one end of the support surface 15 of the support substrate 13 as indicated by the dashed line arrow, taking care not to allow air to enter between the formed second precursor layer 25. Overlap to the other end.
The coating method of the photosensitive resin compositions 20 and 23 is not limited to spreading using the blades 21 and 24, and any of various conventionally known coating methods can be employed.

With reference to FIG. 3 (b), the facing surface 16 of the facing substrate 14 is brought into contact with the superimposed reinforcing sheet 4.
As shown in FIG. 3 (b), the counter substrate 14 is maintained in parallel with a certain distance between the counter surface 16 and the support surface 15 of the support substrate 13 as indicated by white arrows. By pressing in the direction of the support substrate 13, the first precursor layer 22 is pressed against the mold surface 18 of the roughened sheet 19, and the first precursor layer 22, the second precursor layer 25, and the reinforcing sheet 4 are bonded to each other. Crimp.

The UV lamp 17 is turned on in this pressure-bonded state, and both precursor layers 22 and 25 are irradiated with ultraviolet rays as actinic rays through the support substrate 13 and the roughened sheet 19, thereby forming both precursor layers 22 and 25. The photosensitive resin compositions 20 and 23 to be cured are cured to form the surface resin layer 6 and the support resin layer 5.
At the same time, the resin layers 5 and 6 are integrated to form the ink transfer layer 3 having a two-layer structure, and the reinforcing sheet 4 is integrated on the support resin layer 5 side of the formed ink transfer layer 3 [FIG. 3 (b), FIG. 4 (a)].

At this time, the distance between the support surface 15 of the support substrate 13 and the counter surface 16 of the counter substrate 14 is the thickness of the ink transfer layer 3 of the flexographic printing plate 1 to be manufactured, that is, the total of the support resin layer 5 and the surface resin layer 6. The dimension obtained by adding the thickness of the roughened sheet 19 and the thickness of the reinforcing sheet 4 is maintained.
In the above process, as described above, both the reinforcing sheet 4 and the counter substrate 14 are formed of a material having an actinic ray transmission property, and both the precursor layers 22 and 25 are also formed from the counter substrate 14 side. The photosensitive resin compositions 20 and 23 that form the precursor layers 22 and 25 may be cured by being irradiated with ultraviolet rays as actinic rays.

As the photosensitive resin compositions 20 and 23, as described above, a prepolymer having an 1,2-butadiene structure and having an ethylenically unsaturated double bond at the terminal, an ethylenically unsaturated monomer, and light A photosensitive resin composition containing a polymerization initiator is preferably used.
As described above, by changing the types and blending ratios of the above components in the two photosensitive resin compositions 20 and 23, the resins forming the surface resin layer 6 and the support resin layer 5, that is, the respective photosensitive properties. NMP contact angles of the cured products of the resin compositions 20 and 23 can be changed.

4 (a) and 4 (b), a plate sheet 26 which is a laminated body in which the reinforcing sheet 4, the ink transfer layer 3 (support resin layer 5 + surface resin layer 6), and the roughened sheet 19 are integrated. Is taken out from between the support substrate 13 and the counter substrate 14, is turned upside down, and placed on the work table 27 with the reinforcing sheet 4 facing down.
4B, when the roughened sheet 19 is sequentially peeled from one end to the other end of the plate sheet 26 as indicated by the one-dot chain line arrow, the upper surface side of the surface resin layer 6 is roughened. The uneven surface of the mold surface 18 of the surfaced sheet 19 is transferred to form a roughened printing surface 2.

Further, referring to FIG. 4 (c), the non-printing area of the printing pattern 2 on the printing surface 2 exposed by peeling off the roughened sheet 19 is irradiated while scanning with a carbon dioxide laser 29 or the like from the laser head 28. Then, the resin in the irradiated region is thermally removed or mechanically removed (not shown) to form the recess 7 reaching the support resin layer 5.
At the same time or before and after, the four sides of the plate sheet 26 are cut to adjust the overall planar shape to a rectangle, and the vicinity of the two sides parallel to each other is subjected to laser processing or the like, for example, so that the ridges 9 and the grooves 10 1 is completed, the flexographic printing plate 1 shown in FIG. 1 is completed.

The first precursor layer 22 formed in the step of FIG. 2 (b) may be in a semi-cured state by irradiating actinic rays for a short time before laminating the second precursor layer 25 thereon. Thereby, the uniformity of the thickness of the surface resin layer 6 formed by the curing reaction of the first precursor layer 22 can be improved.
And when the 1st precursor layer 22 is made into the semi-hardened state, after apply | coating the photosensitive resin composition 20 on it and forming the 2nd precursor layer 25, the active ray is irradiated to the whole, both precursor layers 22, 25, the integrity of the surface resin layer 6 and the support resin layer 5 formed by curing reaction, that is, the integrity of the ink transfer layer 3, can be improved to the same extent as when the first precursor layer 22 is not semi-cured in advance. It is possible to reliably prevent delamination between the two resin layers 5 and 6 when the flexographic printing plate 1 is used.

<< 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 of the said invention.
According to the present invention, a liquid crystal display device having a uniform liquid crystal alignment film having a uniform thickness, no pinholes and being thin, and having no printing pattern protrusion or bleeding even when printing is repeated, and having excellent printing accuracy. Can continue to manufacture.

Other steps of the production method of the present invention can be carried out in the same manner as in the prior art.
For example, in the case of TFT liquid crystal, a liquid crystal alignment film is formed by flexographic printing using the flexographic printing plate of the present invention on the TFT circuit forming surface and color filter forming surface of the pair of substrates, and the surface of the liquid crystal alignment film is further formed. If necessary, orientation treatment is performed by rubbing or the like.
Next, in a state where the pair of substrates are aligned, a liquid crystal material is sandwiched between them, and the periphery is enclosed and sealed with a sealing material, and the pair of substrates is fixed to each other to form a laminate, and further as necessary. A liquid crystal display element is manufactured by disposing polarizing plates on both outer sides of the laminate.

The present invention is not limited to the examples of the drawings described above.
For example, the reinforcing sheet 4 may be omitted. Further, the first and second precursor layers 22 and 25 may be spread by a roller or the like instead of being pressed by the counter substrate 14 to make the thickness constant.
In addition, various design changes can be made without departing from the scope of the present invention.

Hereinafter, the present invention will be described based on examples and comparative examples, but the configuration of the present invention is not limited to these examples and comparative examples.
<Example 1>
(Photosensitive resin composition)
As the photosensitive resin composition 20 for the surface layer resin layer 6, an ultraviolet curable liquid photosensitive resin composition having an NMP contact angle of 32 ° on the roughened printing surface 2 was prepared.

In addition, as the photosensitive resin composition 23 for the support resin layer 5, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP on the inner surface 8 of the recess 7 was 54 ° was prepared.
(Reinforcing sheet 4)
As the reinforcing sheet 4, a PET sheet (BF / CF manufactured by Sumitomo Rubber Industries, Ltd.) was prepared.
(Roughening sheet 19)
As the roughened sheet 19, the surface of the exposed TPU of a sheet of TPU (Sikuran (registered trademark) SNESS80-150 μm manufactured by Okura Kogyo Co., Ltd.) obtained by bonding a PET sheet having a thickness of 100 μm on one side as a reinforcing sheet, A roughened mold surface 18 was prepared.

(Manufacture of flexographic printing plate 1)
2 (a) to 4 (c), the support substrate of the flexographic printing plate manufacturing apparatus provided with a smooth transparent glass plate having ultraviolet transparency as the support substrate 13 and a counter substrate 14. The above roughened sheet 19 was detachably fixed to the 13 support surfaces 15 through a spray adhesive layer so as to contact the support surface 15 with the mold surface 18 facing upward.

Next, a photosensitive resin composition 20 for the surface resin layer 6 was supplied onto the mold surface 18 and spread using a blade 21 to form a first precursor layer 22. The coating thickness of the photosensitive resin composition 20 was set so that the thickness of the surface resin layer 6 formed through the following steps and below was 0.4 mm.
Next, the photosensitive resin composition 23 for the support resin layer 5 is supplied onto the first precursor layer 22 and spread using the blade 24 to form the second precursor layer 25. The reinforcing sheet 4 was laminated. The coating thickness of the photosensitive resin composition 23 was set so that the thickness of the supporting resin layer 5 formed through the following steps was 1.96 mm.

Next, the facing surface 16 of the facing substrate 14 was brought into contact with the laminated reinforcing sheet 4.
Then, while maintaining the opposing surface 16 parallel to the supporting surface 15 of the supporting substrate 13 with a certain interval, the opposing substrate 14 is supported by the supporting substrate 13 as shown by a black arrow in FIG. , The first precursor layer 22 was pressure-bonded to the mold surface 18 of the roughened sheet 19 and the first precursor layer 22, the second precursor layer 25, and the reinforcing sheet 4 were pressure-bonded to each other. .

  In this state, the UV lamp 17 is turned on, and both precursor layers 22 and 25 are irradiated with ultraviolet rays as active rays through the support substrate 13 and the roughened sheet 19 to form both precursor layers 22 and 25. The photosensitive resin compositions 20 and 23 are cured to form the surface resin layer 6 and the supporting resin layer 5, and the resin layers 5 and 6 are integrated to form the two-layered ink transfer layer 3, and The reinforcing sheet 4 was integrated with the support resin layer 5 side of the ink transfer layer 3 (see FIGS. 3B and 4A). A UV light source manufactured by Philips was used as the light source.

At this time, the distance between the support surface 15 of the support substrate 13 and the counter surface 16 of the counter substrate 14 is the thickness of the ink transfer layer 3 of the flexographic printing plate 1 to be manufactured, that is, between the support resin layer 5 and the surface resin layer 6. The dimension obtained by adding the thickness of the roughened sheet 19 and the thickness of the reinforcing sheet 4 to the total thickness was maintained.
Next, referring to FIGS. 4 (a) and 4 (b), a plate sheet 26 as a laminate of the reinforcing sheet 4, the supporting resin layer 5, the surface resin layer 6, and the roughened sheet 19 is opposed to the supporting substrate 13. It was taken out from between the substrates 14, turned upside down, and placed on the work table 27.

4 (b), the roughened sheet 19 is peeled off sequentially from one end to the other end of the plate sheet 26 as shown by the one-dot chain line arrow, and the upper surface side of the surface layer resin layer 6 is roughened. The uneven surface of the mold surface 18 of the surfaced sheet 19 was transferred to make the printed surface 2 rough.
Next, as shown in FIG. 4C, irradiation is performed while scanning a carbon dioxide laser 29 or the like from the laser head 28 on a non-printing area of the printing pattern on the printing surface 2 exposed by peeling off the roughened sheet 19. And the recessed part 7 which reaches the support resin layer 5 was formed by the laser processing which removes the resin of the irradiated area | region thermally.

Further, the plate sheet 26 is cut on four sides to adjust the entire planar shape to a rectangle, and the vicinity of two sides parallel to each other is laser-processed in the same manner, so that the gripping portion formed by the ridges 9 and the grooves 10 is obtained. 11 and the chuck hole 12 were formed, and the flexographic printing plate 1 shown in FIG. 1 was manufactured.
The laser processing conditions were as follows: carbon dioxide laser output: 400 W × 2 beam, beam diameter: 20 μm, feed pitch: 60 μm, feed rate 140 cm / sec.

After the laser processing, the stain due to the ablation droplet resin was washed using a trade name KS-HG thinner manufactured by Taiyo Kagaku Co., Ltd. and then sufficiently dried.
The thickness of the surface resin layer 6 in the manufactured flexographic printing plate 1 is 0.4 mm, the thickness of the support resin layer 5 is 1.96 mm, and the difference in NMP contact angle between the printing surface 2 and the inner surface 8 of the recess 7 is 22 °. there were.

<Example 2>
As the photosensitive resin composition 20 for the surface resin layer 6, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP on the roughened printing surface 2 is 29 ° is used, and both resin layers are used. Example 1 except that the thickness of the surface resin layer 6 is 0.2 mm and the thickness of the support resin layer 5 is 2.16 mm by adjusting the coating thickness of the photosensitive resin compositions 20 and 23 for 5 and 6 The flexographic printing plate 1 was produced in the same manner as described above.

The difference in the contact angle of NMP between the printing surface 2 and the inner surface 8 of the recess 7 in the manufactured flexographic printing plate 1 was 25 °.
<Example 3>
As the photosensitive resin composition 20 for the surface layer resin layer 6, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP on the roughened printing surface 2 is 25 ° is used, and both resin layers are used. Example 1 except that the thickness of the surface resin layer 6 was adjusted to 0.1 mm and the thickness of the support resin layer 5 was adjusted to 2.26 mm by adjusting the coating thickness of the photosensitive resin compositions 20 and 23 for 5 and 6. The flexographic printing plate 1 was produced in the same manner as described above.

The difference in NMP contact angle between the printing surface 2 and the inner surface 8 of the recess 7 in the manufactured flexographic printing plate 1 was 29 °.
<Example 4>
As the photosensitive resin composition 20 for the surface resin layer 6, an ultraviolet curable liquid photosensitive resin composition having an NMP contact angle of 25 ° on the roughened printing surface 2 is used, and a supporting resin layer is used. As the photosensitive resin composition 23 for 5, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP on the inner surface 8 of the recess 7 is 41 ° is used, and the photosensitive for the both resin layers 5 and 6 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 6 is adjusted to 0.02 mm and the thickness of the support resin layer 5 is set to 2.31 mm by adjusting the coating thickness of the conductive resin compositions 20 and 23. Plate 1 was produced.

The difference in the contact angle of NMP between the printing surface 2 and the inner surface 8 of the recess 7 in the manufactured flexographic printing plate 1 was 16 °.
<Example 5>
As the photosensitive resin composition 20 for the surface resin layer 6, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP of the roughened printing surface 2 is 31 ° is used, and the supporting resin layer As the photosensitive resin composition 23 for 5, an ultraviolet curable liquid photosensitive resin composition in which the NMP contact angle of the inner surface 8 of the recess 7 is 36 ° is used, and the photosensitive resin composition for both the resin layers 5 and 6 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 6 is adjusted to 0.2 mm and the thickness of the support resin layer 5 is set to 2.16 mm by adjusting the coating thickness of the conductive resin compositions 20 and 23. Plate 1 was produced.

The difference in the contact angle of NMP between the printing surface 2 and the inner surface 8 of the recess 7 in the manufactured flexographic printing plate 1 was 5 °.
<Comparative example 1>
The ink transfer layer 3 having a single layer thickness of 2.36 mm was formed using an ultraviolet curable liquid photosensitive resin composition having an NMP contact angle of 36 ° on the roughened printing surface 2. A flexographic printing plate 1 was produced in the same manner as in Example 1 except that.

<Comparative example 2>
The ink transfer layer 3 having a single layer and a thickness of 2.36 mm was formed using an ultraviolet curable liquid photosensitive resin composition having an NMP contact angle of 25 ° on the roughened printing surface 2. A flexographic printing plate 1 was produced in the same manner as in Example 1 except that.
<Comparative Example 3>
As the photosensitive resin composition 20 for the surface resin layer 6, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP on the roughened printing surface 2 is 29 ° is used, and the supporting resin layer As the photosensitive resin composition 23 for 5, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP on the inner surface 8 of the recess 7 is 33 ° is used, and the photosensitive for the both resin layers 5 and 6 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 6 is adjusted to 0.2 mm and the thickness of the support resin layer 5 is set to 2.16 mm by adjusting the coating thickness of the conductive resin compositions 20 and 23. Plate 1 was produced.

The difference in the contact angle of NMP between the printing surface 2 and the inner surface 8 of the recess 7 in the manufactured flexographic printing plate 1 was 4 °.
<Comparative example 4>
As the photosensitive resin composition 20 for the surface resin layer 6, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP on the roughened printing surface 2 is 29 ° is used, and the supporting resin layer As the photosensitive resin composition 23 for 5, an ultraviolet curable liquid photosensitive resin composition in which the contact angle of NMP on the inner surface 8 of the recess 7 is 54 ° is used, and the photosensitive for the both resin layers 5 and 6 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 6 is adjusted to 0.41 mm and the thickness of the support resin layer 5 is set to 1.96 mm by adjusting the coating thickness of the conductive resin compositions 20 and 23. Plate 1 was produced.

The difference in the contact angle of NMP between the printing surface 2 and the inner surface 8 of the recess 7 in the manufactured flexographic printing plate 1 was 25 °.
<Real machine test>
(Flexo printing)
A flexographic printing machine for liquid crystal alignment film printing (A45 manufactured by Nakan Co., Ltd.) was incorporated with flexographic printing plates produced in Examples and Comparative Examples, and anilox roll # 220 [cell volume 6.5 cc / m ² ]. .

The ink for liquid crystal alignment film [Optomer (registered trademark) AL17901 manufactured by JSR Co., Ltd.] is printed on the surface of the simulated substrate for the liquid crystal panel using the flexographic printing machine, and then pre-dried at 120 ° C. for 30 minutes. Thus, a liquid crystal alignment film was formed. The set thickness after preliminary drying of the liquid crystal alignment film was 900 mm.
As the simulated substrate, a substrate in which dots were constructed at a density of 420 ppi in a 5-inch square area was used. The uneven pitch was 3 to 15 μm and the height was 0.3 to 1 μm.

(Measurement of ink protrusion and bleeding)
The amount of ink protrusion (mm) from the rear edge in the printing progress direction of the printed liquid crystal alignment film and the amount of ink bleeding (mm) from the protruding edge were measured.
(Comprehensive evaluation)
The sum of the amount of protrusion and the amount of bleeding was obtained, and comprehensive evaluation was performed according to the following criteria.

A: The sum of the amount of protrusion and the amount of bleeding was within 0.4 mm.
◯: The sum of the amount of protrusion and the amount of bleeding exceeded 0.4 mm and was within 0.6 mm.
(Triangle | delta): The sum total of the protrusion amount and the bleeding amount exceeded 0.6 mm, and was less than 1.0 mm.
X: The sum of the amount of protrusion and the amount of bleeding was 1.0 mm or more.
The above results are shown in Tables 1 and 2.

From the results of Comparative Example 1 in the table, when there is no difference in the contact angle of NMP between the printing surface 2 and the inner surface 8 of the recess 7 in the single-layer normal ink transfer layer 3, It was found that the print pattern was likely to run out and bleed.
Further, from the result of Comparative Example 2, even when the entire single-layer ink transfer layer 3 is formed of a resin having better lipophilicity, the above-described ink pool and the protrusion or bleeding of the printed pattern may not be improved. understood.

Further, from the results of Comparative Example 3, even when the ink transfer layer 3 has a two-layer structure of the surface resin layer 6 and the support resin layer 5, the difference in NMP contact angle between the printing surface 2 and the inner surface 8 of the recess 7 is less than 5 °. In this case, it was found that no effect was obtained, and ink spillage and accompanying printing pattern protrusion and bleeding were still likely to occur.
Further, from the result of Comparative Example 4, in the system with two layers of the surface resin layer 6 and the support resin layer 5, even if the difference in NMP contact angle between the printing surface 2 and the inner surface 8 of the recess 7 is 5 ° or more, When the thickness of the surface resin layer 6 exceeds 0.4 mm, it has been found that the ink pool and the printing pattern protruding or bleeding are likely to occur.

On the other hand, from the results of Examples 1 to 5, in the system in which the ink transfer layer 3 has a two-layer structure of the surface resin layer 6 and the support resin layer 5, the contact angle of NMP between the printing surface 2 and the inner surface 8 of the recess 7 is as follows. It was found that by making the difference of 5 ° or more and the thickness of the surface resin layer 6 0.4 mm or less, it is possible to make it difficult to cause the ink pool and the printing pattern to run out and bleed.
Moreover, considering that the above effects are further improved from the results of Examples 1 to 5, the difference in NMP contact angle between the printing surface 2 and the inner surface 8 of the recess 7 is 10 ° or more even in the above range. It was found that it is preferably 30 ° or less, and the thickness of the surface resin layer 6 is preferably 0.2 mm or less even in the above range.

DESCRIPTION OF SYMBOLS 1 Flexographic printing plate 2 Printing surface 3 Ink transfer layer 4 Reinforcement sheet 5 Support resin layer 6 Surface resin layer 7 Concave 8 Inner surface 9 Convex part 10 Groove 11 Grazing part 12 Chuck hole 13 Support substrate 14 Opposite substrate 15 Support surface 16 Opposing surface 17 Lamp 18 Mold surface 19 Roughened sheets 20 and 23 Photosensitive resin compositions 21 and 24 Blade 22 First precursor layer 25 Second precursor layer 26 Plate sheet 27 Work table 28 Laser head 29 Carbon dioxide laser

Claims (6)

  One side is a printing surface, and the printing surface is provided with an ink transfer layer in which a concave portion corresponding to a non-printing region of a predetermined printing pattern is formed, and the printing surface has N-methyl-2 from the inner surface of the concave portion. -A flexographic printing plate having a pyrrolidone contact angle of 5 ° or more.   The ink transfer layer includes a support resin layer and a surface resin layer that is laminated on the support resin layer to form the printing surface, and the surface resin layer is N more than a resin that forms the support resin layer. -A layer having a thickness of 0.02 mm or more and 0.4 mm or less made of a resin having a small contact angle of methyl-2-pyrrolidone, and the concave portion is formed so as to reach the support resin layer from the printing surface. The flexographic printing plate according to claim 1, wherein the printing surface has a contact angle of the N-methyl-2-pyrrolidone that is smaller than the inner surface of the recess by 5 ° or more.   3. The flexographic printing according to claim 2, wherein the printing surface is made of the resin and is a concavo-convex surface, and a contact angle of the N-methyl-2-pyrrolidone is smaller than the inner surface of the recess by 5 ° or more. Edition.   In the state where the photosensitive resin composition that becomes the basis of the surface resin layer is coated on the mold surface that is the uneven surface, and the photosensitive resin composition that becomes the basis of the support resin layer is laminated thereon, A step of curing the both photosensitive resin compositions by irradiation with actinic rays to form a laminate of the two resin layers, peeling the formed laminate from the mold surface, and the surface resin layer, A step of forming a printing surface having a concavo-convex surface with a surface that has been in contact with the mold surface, and thermally or mechanically cutting off the resin in the non-printing area of the printing surface that is a concavo-convex surface, The manufacturing method of the flexographic printing plate of Claim 2 or 3 including the process of forming the said recessed part which reaches a support resin layer.   Both the surface resin layer and the supporting resin layer have a 1,2-butadiene structure and have a prepolymer having an ethylenically unsaturated double bond at the terminal, an ethylenically unsaturated monomer, and a photopolymerization initiator. The manufacturing method of the flexographic printing plate of Claim 4 which consists of a resin composition.   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 of any one of the said Claim 1 thru | or 3.

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