JP6322871B2 - Flexographic printing plate and manufacturing method thereof, and manufacturing method of liquid crystal display element - Google Patents

Description

  The present invention relates to a flexographic printing plate that can be suitably used for forming, for example, a liquid crystal alignment film of a substrate for a liquid crystal panel by flexographic printing, a method for producing the same, and liquid crystal alignment for a liquid crystal panel using such a flexographic printing plate. The present invention relates to a method for manufacturing a liquid crystal display element including a step of forming a film.

In order to form a liquid crystal alignment film that is required to have high coating quality, that is, as thin as possible and free from pinholes, etc., on the electrode forming surface of the liquid crystal panel substrate constituting the liquid crystal display element Flexographic printing methods having printing characteristics are used.
In general, a flexographic printing plate used in the flexographic printing method includes a single-layered flexible resin layer (flexographic resin layer) whose one surface is a printing surface that holds ink during printing. Further, a reinforcing sheet made of various plastics may be laminated on the opposite surface of the flexo resin layer.

The printed surface needs to have a high holding property with respect to the ink that is the basis of the liquid crystal alignment film. In other words, the printed surface is required to have a good holding property that can be kept as uniform as possible over the entire surface without causing repelling or blurring even with a small amount of ink according to the thickness of the liquid crystal alignment film. .
In order to improve the retainability, it is only necessary to improve the wettability with respect to the ink by increasing the specific surface area by making the printed surface uneven.

For example, in Patent Documents 1 and 2, a printing surface is provided with a large number of minute projections having a geometrical planar shape such as a circle, and the printing surface is formed into a concavo-convex shape by the large number of minute projections and a groove portion therebetween, so It is described to improve the property.
The microprotrusions are formed by, for example, a photolithographic method. In other words, a mask made of a negative or positive film in which a layer of a photosensitive resin composition as a base of a flexo resin layer is prepared and a fine pattern (dot pattern or the like) corresponding to the planar shape of the fine protrusions is formed thereon. The photosensitive resin composition is exposed in a stacked state, selectively cured according to the mask pattern, and then developed to remove the uncured photosensitive resin composition. Many microprotrusions are formed on the printing surface of the flexo resin layer made of

  In Patent Document 3, the printed surface is roughened by using an arbitrary roughening method such as etching or sandblasting, and has irregular irregularities whose shape and size are not regular, such as microprojections. For example, it is described that a rough surface such as a pear ground is finished.

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

Usually, fine irregularities such as various circuits and BM partitions are formed on the surface of the liquid crystal panel substrate to be printed.
Therefore, in the formation of the liquid crystal alignment film by flexographic printing, the flexographic printing plate is brought into pressure contact with the liquid crystal panel substrate by setting a nip amount of about 0.10 to 0.25 mm in the thickness direction so that the printed surface has the above-mentioned unevenness. In general, the ink that is the basis of the liquid crystal alignment film carried on the printing surface is transferred onto substantially the entire surface of the liquid crystal panel substrate.

However, the formation interval of the unevenness formed on the surface of the liquid crystal panel substrate in response to the recent increase in the definition of liquid crystal display elements and the increase in the number of pixels per inch has become narrower and more complicated and complicated. Tend.
Therefore, even if a conventional flexographic printing plate is pressed against a liquid crystal panel substrate with the above-mentioned predetermined nip amount set, a liquid crystal alignment film having a uniform thickness is formed by following the fine irregularities well. This is becoming difficult.

Among them, as described above, the flexographic printing plate in which irregularities are formed on the printing surface by forming minute protrusions or a textured surface as described above has a low followability to the irregularities on the surface of the liquid crystal panel substrate, There is a problem that the thickness of the liquid crystal alignment film becomes extremely small or a pinhole is generated in the irregularities and corners of the surface of the liquid crystal panel substrate.
An object of the present invention is to provide a liquid crystal alignment film that can follow the unevenness well, for example, corresponding to the miniaturization of the unevenness of the surface of the liquid crystal panel substrate, and has a uniform thickness and no pinhole on the surface of the liquid crystal panel substrate. An object of the present invention is to provide a flexographic printing plate that can be formed, a method for producing the same, and a method for producing a liquid crystal display element including a step of forming a liquid crystal alignment film for a liquid crystal panel using the flexographic printing plate.

The present invention includes a flat flexo resin layer, and the flexo resin layer is exposed by being laminated on one side of the main body resin layer having a Shore A hardness of 40 degrees or more and 50 degrees or less , and the main body resin layer. surface is a printing surface, said saw including a soft surface layer resin layer than the body resin layer, and on the opposite side of the main body resin layer reinforced sheet is laminated, an integrated flexographic printing plate.
The present invention, the main body resin layer, and makes a photosensitive resin composition comprising the original surface layer resin layer of a material transparent to active rays for curing reaction, the shape of one side the printed surface A step of forming a first precursor layer by applying a photosensitive resin composition on which the surface resin layer is based on the shaping surface of the mold material corresponding to the shaping surface;
A step of applying a photosensitive resin composition on which the main body resin layer is based on the first precursor layer and laminating a second precursor layer,
Laminating the reinforcing sheet to the second precursor layer, and said first and said second precursor layer, and the surface resin layer by curing reaction by irradiation of the active light through the mold member and said body resin layer Forming the laminate with the reinforcing sheet, and then peeling the laminate from the shaping surface;
Is a method for producing a flexographic printing plate of the present invention.

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

In order to improve the followability of the printing surface to the unevenness, it is conceivable to make the entire single-layer flexo resin layer of the conventional flexographic printing plate softer than the current state.
However, in that case, the flexographic resin layer is likely to be greatly deformed in the shearing direction at the time of printing, and printing misalignment, distortion, and protrusion are likely to occur, and the printing accuracy of the flexographic printing plate is lowered.

Further, when the printing is repeated, the flexo resin layer tends to be so-called sag in a short period of time, and the durability of the flexographic printing plate is lowered. Further, when the settling occurs, there is a problem that the predetermined printing pressure cannot be maintained and the printing thickness is reduced.
On the other hand, according to the present invention, the flexo resin layer, which has been a single layer in the past, has a laminated structure of a main body resin layer and a surface layer resin layer, of which the main body resin layer has the same degree of hardness as the conventional flexo resin. While preventing the entire layer from being greatly deformed in the shearing direction during printing and reducing printing accuracy or causing sag in a short period of time and lowering durability, the surface resin layer is made more than the main resin layer. By making it soft, it is possible to improve the followability of the printed surface, which is the exposed surface of the surface resin layer, with respect to the unevenness.

Therefore, according to the flexographic printing plate of the present invention, for example, the printing surface can be made to follow the unevenness on the surface of the liquid crystal panel substrate in accordance with the miniaturization of the unevenness of the surface of the liquid crystal panel substrate. It is possible to form a liquid crystal alignment film that is uniform and has no pinholes.
Further, according to the method for producing a flexographic printing plate of the present invention, the flexographic printing plate of the present invention having such a laminated structure can be produced with high productivity and low cost.

  Furthermore, according to the method for manufacturing a liquid crystal display element of the present invention, a liquid crystal display element including a liquid crystal alignment film having a uniform thickness and no pinholes can be manufactured based on the above laminated structure.

FIGS. 4A to 4D are cross-sectional views illustrating respective steps of an example of an embodiment of the method for producing a flexographic printing plate of the present invention. FIGS. 7A to 7C are cross-sectional views for explaining subsequent steps of the manufacturing method of the example of FIG. FIGS. 2A and 2B are cross-sectional views for explaining an example of a method for removably fixing a roughened sheet to the surface of a flat support substrate in the manufacturing methods of the examples of FIGS. is there.

《Flexographic printing plate》
The flexographic printing plate of the present invention includes a flat flexo resin layer, and the flexo resin layer is laminated on one side of the main body resin layer having a Shore A hardness of 40 degrees or more and 50 degrees or less. are exposed surface is a printing surface, the soft look including the surface resin layer than the body resin layer, and on the opposite side of the main body resin layer are laminated reinforcing sheet, wherein the integrated .
<Photosensitive resin composition>
Both the main body resin layer and the surface resin layer constituting the flexo resin layer are preferably produced by the production method of the present invention described later using a photosensitive resin composition.

The photosensitive resin composition includes, for example, a prepolymer having a 1,2-butadiene structure and having an ethylenic double bond at the end, a monomer having at least one ethylenically unsaturated group, and a photopolymerization initiator. A composition.
The photopolymerization initiator is preferably a benzoin alkyl ether, and the ratio of benzoin that causes yellowing of the flexographic printing plate by reacting with visible light from a fluorescent lamp or the like is 500 ppm or less of the total amount of the photosensitive resin composition. Some are preferably used. Thereby, it is possible to obtain a flexographic printing plate excellent in weather resistance that does not turn yellow in a short period of time.

In order to change the hardness of the main body resin layer and the surface resin layer, for example, the kind and blending ratio of the prepolymer and monomer constituting the photosensitive resin composition, the blending ratio of the photopolymerization initiator, and the like may be adjusted.
<Main body resin layer>
The main body resin layer can be a layer having the same degree of hardness as a conventional flexo resin layer having a single layer structure as described above. That the hardness of the main body resin layer, on to 40 degrees or expressed in Shore A hardness, Ru der than 50 degrees.

For Shore A hardness of the main body resin layer is the main resin layer is too soft is less than this range, the whole printing accuracy increased easily deformed in the shearing direction when printing flexographic resin layer you decrease. Also you reduced durability is liable to sag overall flexographic resin layer upon repeated printing.
On the other hand, when the Shore A hardness of the main body resin layer exceeds the above range, the handleability of the flexographic printing plate such as the workability when the flexographic printing plate is wound around the plate cylinder of a flexographic printing machine is lowered. The

On the other hand, by making the Shore A hardness of the main body resin layer within the above range, high printing accuracy and durability are maintained while maintaining the handling property of the flexographic printing plate at the same level as that of the conventional single layer structure. Can be secured.
In the present invention, the Shore A hardness of the main body resin layer and the surface resin layer is determined by the Japanese Industrial Standard JIS K6253-3 _{: 2012} “Vulcanized Rubber and Thermoplastic Rubber—How to Obtain Hardness—Part 3: Durometer Hardness “It shall be expressed as a type A durometer hardness value after 15 seconds of indentation measured at room temperature (5-35 ° C.) in accordance with the measurement method described.

The thickness of the main body resin layer can be arbitrarily set according to the thickness of the surface resin layer to be laminated, or the thickness of the flexo resin layer, that is, the total thickness of the main body resin layer and the surface resin layer.
Of these, the total thickness of both layers is preferably set to the same level as the thickness of a conventional flexo resin layer having a single-layer structure, from the viewpoint of the handleability of the flexographic printing plate.
That is, the total thickness of both resin layers is 1.5 mm or more, particularly 2 mm or more, preferably 3.5 mm or less, particularly 3 mm or less.

The thickness of the main resin layer is preferably a value obtained by subtracting the thickness of the surface resin layer from the total thickness. That is, according to the thickness of the surface resin layer, the thickness of the main body resin layer may be set so that the total thickness is in the above range.
<Surface resin layer>
As described above, the surface resin layer needs to be a softer layer than the main body resin layer.

Although it can be arbitrarily set how much the surface resin layer is softer than the main body resin layer, the surface resin layer is expressed by the difference in Shore A hardness with the main body resin layer and is softened in a range of 3 degrees or more. Preferably, the softening is preferably performed within a range of 21 degrees or less.
That is, if the difference in Shore A hardness between the two resin layers is less than this range, the surface resin layer cannot be sufficiently softened depending on the specific Shore A hardness range of the two resin layers. There is a possibility that the effect of improving the followability of the printed surface, which is the exposed surface, with respect to the unevenness cannot be sufficiently obtained.

Therefore, for example, when the printed surface cannot follow the unevenness of the surface of the liquid crystal panel substrate satisfactorily, and a liquid crystal alignment film having a uniform thickness and no pinholes cannot be formed on the surface of the liquid crystal panel substrate There is.
On the other hand, if the difference in Shore A hardness between the two resin layers exceeds the above range, the surface resin layer becomes too soft, so that when the printing is repeated, the surface resin layer tends to sag in a short period of time. This may reduce the durability of the flexographic printing plate.

On the other hand, by setting the difference in Shore A hardness between the two resin layers to 3 degrees or more and 21 degrees or less, while maintaining the high durability of the flexographic printing plate by making the surface resin layer difficult to sag, The followability of the printed surface, which is the exposed surface of the surface resin layer, can be improved.
In consideration of further improving this effect, the surface resin layer is preferably expressed as a difference in Shore A hardness from the main body resin layer and is preferably softened in a range of 5 degrees or more, and in a range of 12 degrees or less. It is preferable to make it soft.

The thickness of the surface resin layer is preferably 0.1 mm or more, and preferably 0.8 mm or less.
If the thickness of the surface resin layer is less than the above range, even if the surface resin layer is sufficiently soft, the deformation amount in the thickness direction of the surface resin layer is limited. There is a possibility that the followability of the surface with respect to the unevenness is lowered.

Therefore, for example, when the printed surface cannot follow the unevenness of the surface of the liquid crystal panel substrate satisfactorily, and a liquid crystal alignment film having a uniform thickness and no pinholes cannot be formed on the surface of the liquid crystal panel substrate There is.
On the other hand, when the thickness exceeds the above range, the surface resin layer is likely to be greatly deformed in the shear direction during printing, and the printing accuracy of the flexographic printing plate may be lowered. Further, when the printing is repeated, the surface resin layer tends to sag in a short period of time, and the durability of the flexographic printing plate may be lowered.

On the other hand, by setting the thickness of the surface resin layer to 0.1 mm or more and 0.8 mm or less, the surface resin layer can be prevented from being deformed in the shear direction and high printing accuracy can be maintained. The followability of the printed surface, which is the exposed surface of the surface resin layer, can be improved while maintaining high durability by making it difficult to sag.
In consideration of further improving this effect, the thickness of the surface resin layer is preferably 0.2 mm or more, and more preferably 0.6 mm or less even in the above range.

The specific Shore A hardness of the surface resin layer may be a value obtained by subtracting the above difference from the preferred range of the Shore A hardness of the main body resin layer described above.
However, in consideration of further improving the effect of softening the surface resin layer described above, the Shore A hardness of the surface resin layer is preferably 19 degrees or more, particularly preferably 30 degrees or more, and 38 It is preferable that the angle is not higher than 36 degrees, particularly not higher than 36 degrees.

<Reinforcing sheet>
The flexographic printing plate of the present invention, the main body resin layer, to the side where the surface resin layer is laminated opposite surface, that have a conventional Similarly reinforcing sheet. This increases the overall tensile strength of the flexographic printing plate and further improves the handling of the flexographic printing plate, such as workability when the flexographic printing plate is wrapped around a plate cylinder of a flexographic printing press. .

As a reinforcing sheet, for example, a sheet made of a thermoplastic resin such as polyethylene (PE), polypropylene (PP), thermoplastic polyurethane (TPU), polyethylene terephthalate (PET), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), etc. Or a metal sheet, a laminate sheet of both, etc. can be used.
The thickness of the reinforcing sheet can be arbitrarily set.

<Production method of flexographic printing plate>
1 (a) to 1 (d) and FIGS. 2 (a) to 2 (c) are cross-sectional views illustrating respective steps of an example of the embodiment of the method for producing a flexographic printing plate of the present invention.
Note Of flexographic printing plate of the present invention in the example of figure, illustrating a case of manufacturing the printing surface is the exposed surface of the surface layer a resin layer is roughened for example, flexographic printing plate of the present invention The manufacturing method is not limited to such an example.

Referring to FIG. 1 (a), in the manufacturing method of this example, first, it is made of a hard material such as glass, acrylic resin, polycarbonate resin, polyester resin or the like, and the photosensitive resin composition is cured. A supporting substrate 1 having transparency to actinic rays such as ultraviolet rays is prepared.
Then, on the upper surface 2 in the figure of the support substrate 1, a roughened sheet 4 having a roughened shaped surface 3 having a concavo-convex shape corresponding to the shape of the printing surface on one side is applied to the shaped surface 3. With the opposite surface (opposite surface) 5 facing down and the opposite surface 5 in contact with the surface 2, for example, from one end to the other as shown by the dashed line arrow in FIG. Fix in a detachable manner, for example by stacking in order.

In the drawing, the unevenness constituting the shaping surface 3 is drawn with a large emphasis so as to be easily understood. However, the actual unevenness is shown in the figure because it does not affect the shape of the liquid crystal alignment film to be printed. It is a minute one that cannot be distinguished from the size of the roughened sheet 4.
The roughened sheet 4 is made of, for example, a thermoplastic resin such as PE, PP, TPU, PET, FEP, and the surface of the sheet having transparency to actinic rays is formed by, for example, pressure sheet molding using an embossing roll. It is preferable to use a roughened surface.

According to such pressure sheet molding, for example, there is an advantage that even a roughened sheet 4 having a large area corresponding to a liquid crystal display element having a large screen can be easily produced continuously and in large quantities.
Of the above, the roughened sheet 4 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 substrate 1. In some cases, it is difficult to uniformly adhere to the surface 2 without wrinkles.

In that case, a reinforcing sheet made of, for example, PET or the like and having transparency to actinic rays may be bonded to the opposite surface 5 of the roughened sheet 4.
The roughened sheet 4 is applied to the support substrate 1 by a shearing force when the liquid photosensitive resin composition is spread on the roughened sheet 4 or a shrinkage force when the photosensitive resin composition is cured. In order to prevent misalignment and facilitate replacement of the roughened sheet 4 after use, it can be detachably attached to the surface 2 of the support substrate 1 by any of the following methods (i) to (iii), for example. It is preferable to fix to.

(i) Removably attached to the surface 2 of the support substrate 1 through a weak adhesive layer made of a material having transparency to actinic rays.
(ii) A suction groove (not shown) is formed on the surface 2 of the support substrate 1, and vacuum suction is performed through the suction groove so as to be detachably attached to the surface 2 by suction.
(iii) Removably press-fixed to the surface of the support substrate 1 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 1.

  Among these, as the weak adhesive layer used for the adhesive fixation of (i), various adhesives having weak adhesiveness to the forming material of the support substrate 1 and the roughened sheet 4 and having transparency to actinic rays Any of these layers can be used. The weak adhesive layer is formed by applying an adhesive to at least one of the surface 2 of the support substrate 1 and the opposite surface 5 of the roughened sheet 4 by various application methods such as spray application.

After the weak adhesive layer is formed on the surface 2 of the support substrate 1 and / or the opposite surface 5 of the roughened sheet 4, the roughened sheet 4 is supported on the support substrate as shown by the dashed line arrow in FIG. When the layers 1 are overlapped in order from one end of the surface 2 to the other end, taking care not to allow air to enter between the opposite surface 5 and the surface 2, the surface of the roughened sheet 4 is surfaced by the adhesive force of the weak adhesive layer. 2 can be fixed.
Further, in order to remove the fixed roughened sheet 4 from the surface 2, the roughened sheet 4 is removed from the other end of the support substrate 1 to one end, for example, opposite to the arrow in FIG. What is necessary is just to peel off in order, resisting adhesive force.

In order to perform the adsorption fixation of (ii), the surface 2 of the support substrate 1 is finished smoothly, and suction grooves are formed on substantially the entire surface 2. The suction groove is connected to a vacuum system including a vacuum pump.
Then, the vacuum system is operated with the roughened sheet 4 placed on the surface 2 of the support substrate 1 with the opposite surface 5 facing down, or the previously operated vacuum system is connected to the suction groove, etc. The roughened sheet 4 can be fixed on the surface 2 by vacuum suction through the suction groove.

To remove the fixed roughened sheet 4 from the surface 2, the vacuum system may be stopped or the connection between the vacuum system and the suction groove may be interrupted.
3 (a) and 3 (b) are cross-sectional views for explaining the method of pressing and fixing (iii) above.
With reference to both the drawings, in this press-contact fixing method, for example, a pair of roughened sheets 4 formed in a rectangular shape corresponding to the shape of the screen of the liquid crystal display element is held over the entire length of two sides parallel to each other. The chuck jig C is prepared.

As the roughened sheet 4, a sheet having a length L ₁ between the two sides that is longer than the corresponding dimension L _{2 of} the support substrate 1 that is also formed in a rectangular shape is prepared. The entire length is held by the chuck jig C. Although not shown, the roughened sheet 4 holds the shaping surface 3 with the shaping surface 3 facing upward in the drawing.
Then, by placing the chuck jig C at a distance from the dimension L ₂ of the support substrate 1, the roughened sheet 4 is stretched between the chuck jigs C without sagging (FIG. 3 ( a)).

Next, in this state, the chuck jig C is moved downward in the figure, so that the roughened sheet 4 stretched between the chuck jigs C is supported by the support substrate as shown by the white arrow in FIG. When the surface is lowered in the direction of the surface 2 and pressed against the surface 2 without a gap as shown in FIG. 3B, the roughened sheet 4 can be fixed on the surface 2.
Further, in order to remove the fixed roughened sheet 4 from the surface 2, the roughened sheet 4 is moved together with the pair of chuck jigs C from the surface 2 in the opposite direction to the arrow in FIG. That's fine.

  Next, referring to FIG. 1B, in the manufacturing method of this example, the surface layer resin is formed on the shaping surface 3 of the roughened sheet 4 fixed on the surface 2 of the support substrate 1 by any one of the above methods. A liquid photosensitive resin composition 6 that is the basis of the layer is supplied and, for example, by using a blade 7, a predetermined distance from one end to the other end of the surface 2 of the support substrate 1 is indicated by a one-dot chain arrow in the figure. The first precursor layer 8 made of the photosensitive resin composition 6 and serving as the basis of the surface resin layer is formed by spreading the coating so as to have a thickness of.

  Next, referring to FIG. 1 (c), a liquid photosensitive resin composition 9 that becomes the base resin layer is supplied onto the first precursor layer 8. As indicated by the chain line arrow, the surface of the support substrate 1 is spread from one end to the other end so as to have a predetermined thickness, thereby forming the main body resin layer made of the photosensitive resin composition 9. While forming the second precursor layer 11, almost at the same time, taking care not to enter air between the second precursor layer 11, one end of the surface 2 of the support substrate 1 as indicated by the dashed line arrow above. The reinforcing sheets 12 are overlapped in order from the other end to the other end.

In addition, the coating method of the photosensitive resin compositions 6 and 9 is not limited to the spreading using the blades 7 and 10, and any of various conventionally known coating methods can be employed.
Next, referring to FIG. 1 (d), the opposing surface 14 of the opposing substrate 13 is brought into contact with the reinforcing sheet 12.
And while maintaining the opposing surface 14 of the opposing substrate 13 parallel to the surface 2 with a certain distance, the opposing substrate 13 is directed in the direction of the support substrate 1 as indicated by the black arrow in FIG. By pressing, the first precursor layer 8 is pressure-bonded to the shaping surface 3 of the roughened sheet 4, and the first precursor layer 8, the second precursor layer 11, and the reinforcing sheet 12 are pressure-bonded to each other.

  Then, in this state, both precursor layers 8 and 11 are exposed with actinic rays through the support substrate 1 and the roughened sheet 4 as indicated by solid arrows in FIG. The photosensitive resin compositions 6 and 9 to be formed are cured to form the surface resin layer 15 and the main body resin layer 16, and the resin layers 15 and 16 are integrated to form a flexo resin layer 17 having a two-layer structure. In addition, the reinforcing sheet 12 is integrated with the surface of the flexo resin layer 17 on the main body resin layer 16 side (see FIGS. 1D and 2A).

At this time, the distance between the surface 2 of the support substrate 1 and the opposing surface 14 of the opposing substrate 13 is the thickness of the flexographic resin layer 17 of the flexographic printing plate to be manufactured, that is, the total of the main body resin layer 16 and the surface resin layer 15. The dimension obtained by adding the thickness of the roughened sheet 4 and the thickness of the reinforcing sheet 12 to the thickness is maintained.
The counter substrate 13 can be formed of any material such as metal, glass, or hard resin.

  In particular, the counter substrate 13 is formed of a material having transparency to actinic rays similar to the support substrate 1, and the reinforcing sheet 12 is also formed of a material having transparency to actinic rays similar to the roughened sheet 4. The photosensitive resin compositions 6 and 9 that form the first and second precursor layers 8 and 11 may also be exposed to an actinic ray to cause a curing reaction from the counter substrate 13 side.

Next, referring to FIGS. 2 (a) and 2 (b), the laminate 18 of the reinforcing sheet 12, the main body resin layer 16, the surface layer resin layer 15, and the roughened sheet 4 is taken out from between the support substrate 1 and the counter substrate 13. Then, it is turned upside down and placed on the work table 19 with the reinforcing sheet 12 facing downward.
Then, when the roughened sheet 4 is sequentially peeled from one end to the other end of the laminate 18 as shown by the dashed line arrow in FIG. 2B, the upper surface side of the surface resin layer 15 is roughened. The uneven surface of the shaping surface 3 of the surfaced sheet 4 is transferred to form a roughened printing surface 20.

  Next, as shown in FIG. 2C, a region other than the region corresponding to the printing pattern on the printing surface 20 is irradiated with, for example, the surface resin layer 15 while scanning the carbon dioxide laser 22 from the laser head 21 and thermally. By removing or mechanically removing although not shown, the flexographic printing plate 23 in which the printing surface 20 is patterned so as to correspond to a predetermined printing pattern is manufactured.

The first precursor layer 8 formed in the step of FIG. 1 (b) is semi-cured by irradiating actinic rays for a short time before the second precursor layer 11 is laminated thereon in the step of FIG. 1 (c). It may be in the state of. Thereby, the uniformity of the thickness of the surface resin layer 15 formed by the curing reaction of the first precursor layer 8 can be improved.
And since the 1st precursor layer 8 is a semi-hardened state, after apply | coating the photosensitive resin composition 9 on it and forming the 2nd precursor layer 11, it irradiates actinic light to the whole, both precursor layers 8, 11, the integrity of the surface resin layer 15 and the main body resin layer 16 formed by curing reaction, that is, the integrity of the flexo resin layer 17 can be improved to the same extent as when the first precursor layer 8 is not semi-cured in advance. It is possible to reliably prevent delamination between the resin layers when the flexographic printing plate 23 is used.

Further, the flexographic printing plate 23 of the present invention can be formed into a finished form in some cases without the printing surface 20 being patterned. When patterning, not only the surface resin layer 15 but also a part in the thickness direction of the main body resin layer 16 may be removed. Conversely, a part of the surface resin layer 15 in the thickness direction including the printing surface 20 may be removed. You may just remove it.
<< Method for manufacturing liquid crystal display element >>
This invention is a manufacturing method of the liquid crystal display element including the process of forming the liquid crystal aligning film of the board | substrate for liquid crystal panels by flexographic printing using the flexographic printing plate of the said invention.

According to the present invention, the printing surface of the flexographic printing plate can be made to follow the unevenness on the surface of the liquid crystal panel substrate in accordance with the miniaturization of the surface, so that the liquid crystal alignment film has a uniform thickness and no pinholes. 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 then a liquid crystal alignment film is formed by flexographic printing using the flexographic printing plate of the present invention. A liquid crystal panel substrate is produced by subjecting the surface of the film to orientation treatment by rubbing or the like, if necessary.

  Next, two liquid crystal panel substrates are prepared, and in a state where the transparent electrode layers are aligned, a liquid crystal material is sandwiched between the two liquid crystal panel substrates and fixed to each other to form a laminate. Further, if necessary, a polarizing plate is disposed on both outer sides of the laminate to produce a liquid crystal display element.

<Example 1>
(Photosensitive resin composition)
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a Shore A hardness of 20 degrees after curing was prepared.
The photosensitive resin composition 9 for the main body resin layer 16 is an ultraviolet curable liquid photosensitive resin composition having an Shore A hardness of 41 degrees after curing [NK resin manufactured by Sumitomo Rubber Industries, Ltd. ] Was prepared.

(Reinforcing sheet 12)
As the reinforcing sheet 12, a PET sheet [BF / CF manufactured by Sumitomo Rubber Industries, Ltd.] was prepared.
(Roughening sheet 4)
As the roughened sheet 4, the exposed TPU surface of a TPU sheet [Silklon (registered trademark) SNSESS 80-150 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 is roughened A surface forming shaped surface 3 was prepared.

(Manufacture of flexographic printing plate 23)
Referring to FIGS. 1A to 1D, the surface of the support substrate 1 of the flexographic printing plate manufacturing apparatus provided with a smooth transparent glass plate having ultraviolet transparency as the support substrate 1 and a counter substrate 13. 2, the previous roughened sheet 4 was detachably fixed through a layer of spray adhesive so that the shaping surface 3 was up and the opposite surface 5 was down so that the opposite surface 5 was in contact with the surface 2.

Next, a photosensitive resin composition 6 for the surface resin layer 15 was supplied onto the shaping surface 3 and spread using a blade 7 to form a first precursor layer 8. The coating thickness of the photosensitive resin composition 6 was set such that the thickness of the surface resin layer 15 formed through the following steps and below was 0.10 mm.
Next, the photosensitive resin composition 9 for the main body resin layer 16 is supplied onto the first precursor layer 8 and spread using the blade 10 to form the second precursor layer 11. A reinforcing sheet 12 was laminated. The coating thickness of the photosensitive resin composition 9 was set so that the thickness of the main body resin layer 16 formed through the following steps was 2.26 mm.

Next, the opposing surface 14 of the opposing substrate 13 was brought into contact with the laminated reinforcing sheet 12.
The counter substrate 13 is moved in the direction of the support substrate 1 as indicated by the black arrow in FIG. By pressing, the first precursor layer 8 was pressure-bonded to the shaping surface 3 of the roughened sheet 4, and the first precursor layer 8, the second precursor layer 11, and the reinforcing sheet 12 were pressure-bonded to each other.

  In this state, both precursor layers 8 and 11 are exposed to active rays through the support substrate 1 and the roughened sheet 4 as indicated by solid arrows in FIG. The surface resin layer 15 and the main body resin layer 16 are formed by curing reaction of the photosensitive resin compositions 6 and 9 forming the resin, and the two-layer structure flexo resin layer 17 is formed by integrating both the resin layers 15 and 16. In addition, the reinforcing sheet 12 was integrated with the surface of the flexo resin layer 17 on the main body resin layer 16 side (see FIGS. 1D and 2A). A UV light source manufactured by Philips was used as the light source.

At this time, the distance between the surface 2 of the support substrate 1 and the opposing surface 14 of the counter substrate 13 is the thickness of the flexo resin layer 17 of the flexographic printing plate 23 to be manufactured, that is, the total of the main resin layer 16 and the surface resin layer 15. The dimension obtained by adding the thickness of the roughened sheet 4 and the thickness of the reinforcing sheet 12 to the thickness of was maintained.
Next, referring to FIGS. 2 (a) and 2 (b), a laminate 18 of the reinforcing sheet 12, the main body resin layer 16, the surface layer resin layer 15, and the roughened sheet 4 is interposed between the support substrate 1 and the counter substrate 13. The sheet was taken out, turned upside down, and placed on the work table 19 with the reinforcing sheet 12 facing downward.

Then, as shown by the one-dot chain line arrow in FIG. 2B, the roughened sheet 4 is peeled off in order from one end to the other end of the laminate 18, and the upper surface side of the surface layer resin layer 15 is roughened. A flexographic printing plate 23 having a roughened printing surface 20 by transferring the uneven shape of the shaping surface 3 of the surfaced sheet 4 was produced.
Next, as shown in FIG. 2 (c), the area other than the area corresponding to the printing pattern on the printing surface 20 is thermally removed by irradiating the surface resin layer 15 together with the carbon dioxide laser 22 from the laser head 21 while scanning. As a result, the printing surface 20 was patterned to correspond to a predetermined printing pattern.

The conditions for patterning were carbon dioxide laser output: 400 W × 2 beams, beam diameter: 20 μm, feed pitch: 60 μm, and feed rate of 140 cm / second.
After the patterning, the soil with the ablation resin was washed using a trade name KS-HG thinner manufactured by Taiyo Kagaku Co., Ltd. and then sufficiently dried.
In the manufactured flexographic printing plate 23, the thickness of the surface resin layer 15 is 0.1 mm, the thickness of the main body resin layer 16 is 2.26 mm, and the difference in Shore A hardness between the surface resin layer 15 and the main body resin layer 16 is 21 degrees. It was.

<Example 2>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 27 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 15 was adjusted to 0.15 mm and the thickness of the main body resin layer 16 was adjusted to 2.21 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the main body resin layer 16 in the manufactured flexographic printing plate 23 was 14 degrees.
<Example 3>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 32 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing is performed in the same manner as in Example 1 except that the thickness of the surface resin layer 15 is adjusted to 0.25 mm and the thickness of the main body resin layer 16 is set to 2.11 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the main body resin layer 16 in the manufactured flexographic printing plate 23 was 9 degrees.
<Example 4>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 34 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 15 is adjusted to 0.45 mm and the thickness of the main body resin layer 16 is set to 1.91 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the body resin layer 16 in the manufactured flexographic printing plate 23 was 7 degrees.
<Example 5>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 36 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing is performed in the same manner as in Example 1 except that the thickness of the surface resin layer 15 is adjusted to 0.35 mm and the thickness of the main body resin layer 16 is set to 2.01 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the main body resin layer 16 in the manufactured flexographic printing plate 23 was 5 degrees.
<Example 6>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 38 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 15 is adjusted to 0.45 mm and the thickness of the main body resin layer 16 is set to 1.91 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the main resin layer 16 in the manufactured flexographic printing plate 23 was 3 degrees.
<Example 7>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 38 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 15 was adjusted to 0.80 mm and the thickness of the main body resin layer 16 was adjusted to 1.56 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the main resin layer 16 in the manufactured flexographic printing plate 23 was 3 degrees.
<Example 8>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 36 degrees is used, and the photosensitive resin for the main body resin layer 16 is used. As the composition 9, an ultraviolet curable liquid photosensitive resin composition having a Shore A hardness of 48 degrees after curing is used, and the photosensitive resin compositions 6 and 9 for both the resin layers 15 and 16 are applied. A flexographic printing plate 23 is produced in the same manner as in Example 1 except that the thickness of the surface resin layer 15 is adjusted to 0.55 mm and the thickness of the main body resin layer 16 is set to 1.81 mm by adjusting the thickness and the like. Patterned.

The difference in Shore A hardness between the surface resin layer 15 and the main body resin layer 16 in the manufactured flexographic printing plate 23 was 12 degrees.
<Example 9>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 39 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 15 was adjusted to 0.80 mm and the thickness of the main body resin layer 16 was adjusted to 1.56 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the main body resin layer 16 in the manufactured flexographic printing plate 23 was 1 degree.
<Example 10>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 18 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 15 was adjusted to 0.15 mm and the thickness of the main body resin layer 16 was adjusted to 2.21 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the body resin layer 16 in the manufactured flexographic printing plate 23 was 23 degrees.
<Example 11>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 20 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing in the same manner as in Example 1 except that the thickness of the surface resin layer 15 was adjusted to 0.05 mm and the thickness of the main body resin layer 16 was adjusted to 2.31 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the main body resin layer 16 in the manufactured flexographic printing plate 23 was 21 degrees.
<Example 12>
As the photosensitive resin composition 6 for the surface resin layer 15, an ultraviolet curable liquid photosensitive resin composition having a cured Shore A hardness of 34 degrees is used, and the photosensitive resin composition for both the resin layers 15 and 16 is used. Flexographic printing is performed in the same manner as in Example 1 except that the thickness of the surface resin layer 15 is adjusted to 1.00 mm and the thickness of the main body resin layer 16 is 1.36 mm by adjusting the coating thickness of the adhesive resin compositions 6 and 9. A plate 23 was produced and the printing surface 20 was patterned.

The difference in Shore A hardness between the surface resin layer 15 and the body resin layer 16 in the manufactured flexographic printing plate 23 was 7 degrees.
<Comparative example 1>
A flexo resin layer having a single layer thickness of 2.36 mm was formed using a liquid photosensitive resin composition having a Shore A hardness of 41 degrees after curing, in the same manner as in Example 1, except that the flexo resin layer was formed. A printing plate was produced and the printing surface was patterned.

<Comparative example 2>
A flexo resin layer having a single layer thickness of 2.36 mm was formed using a liquid photosensitive resin composition having a Shore A hardness of 20 degrees after curing, in the same manner as in Example 1, except that the flexo resin layer was formed. A printing plate was produced and the printing surface was patterned.
<Real machine test>
(Flexo printing)
A flexographic printing machine for liquid crystal alignment film printing (A45 manufactured by Nakan Techno 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.

(Thickness uniformity evaluation)
The thickness of the liquid crystal alignment film after preliminary drying was measured, and the thickness uniformity was evaluated according to the following criteria.
OO: The thickness range was within 900 ± 36 mm. Hide.
◯: The thickness range was within 900 ± 65 mm. Excellent.
○: The thickness range was within 900 ± 90 mm. Good.

Δ: The thickness range was within 900 ± 135 mm. Yes.
X: The thickness range exceeded 900 ± 135 mm. Impossible.
(Evaluation of printing accuracy)
The above flexographic printing was continuously performed for 2000 sheets, the amount of deviation between the printing start positions of the first and 2000th printing sheets was measured, and the quality of printing accuracy was evaluated according to the following criteria.

OO: Deviation amount was within ± 200 μm. Hide.
◯: Deviation amount was within ± 400 μm. Excellent.
○: Deviation amount was within ± 600 μm. Good.
Δ: Deviation amount was within ± 800 μm. Yes.
X: The amount of deviation exceeded ± 800 μm. Impossible.

(Durability evaluation)
The flexographic printing was continuously performed while continuously measuring the thickness of the printed liquid crystal alignment film. The relationship between the amount of decrease in the thickness of the liquid crystal alignment film accompanying the decrease in printing pressure due to the sag of the flexo resin layer and the number of printed sheets was determined, and the quality of the flexographic printing plate was evaluated based on the following criteria.

OO: Even when 20,000 sheets or more were printed, the amount of decrease in the thickness of the liquid crystal alignment film was within 65 mm. Hide.
◯: When printing 15,000 sheets or more and less than 20,000 sheets, the amount of decrease in the thickness of the liquid crystal alignment film was within 65 mm. Excellent.
A: The amount of decrease in the thickness of the liquid crystal alignment film after printing 15,000 sheets was within 90 mm. Good.
Δ: In printing of less than 55,000 sheets, the amount of decrease in the thickness of the liquid crystal alignment film was within 90 mm. Yes.

X: The amount of decrease in the thickness of the liquid crystal alignment film exceeded 90 mm after printing less than 55,000 sheets. Impossible.
The above results are shown in Tables 1 and 2.

From the results of Comparative Example 1 in Table 2, a single-layer normal flexographic resin layer has insufficient followability of the printed surface against unevenness, and the liquid crystal panel substrate has a uniform thickness and no pinholes on the surface. It was found that an alignment film cannot be formed.
Further, from the result of Comparative Example 2, when the entire flexo resin layer is softened in order to improve the followability of the printing surface, the flexo resin layer is greatly deformed in the shearing direction during printing, and the printing accuracy of the flexographic printing plate is increased. It has been found that when the printing is repeated, the flexographic resin layer sags in a short period of time and the durability of the flexographic printing plate is lowered.

  On the other hand, from the results of Examples 1 to 12 in Tables 1 and 2, the flexo resin layer 17 has a two-layer structure of the surface resin layer 15 and the main body resin layer 16, and the surface resin layer 15 is more than the main body resin layer 16. By making it soft, the deformation of the entire flexo resin layer 17 in the shear direction is suppressed to maintain high printing accuracy, and the printing surface 20 with respect to unevenness is maintained while maintaining high durability by making it difficult to sag. It was found that the followability was improved and a liquid crystal alignment film having a uniform thickness and no pinholes could be formed on the surface of the liquid crystal panel substrate.

Moreover, considering that the effect is further improved from the results of Examples 1 to 12, the surface resin layer 15 is expressed by a difference in Shore A hardness from the main body resin layer 16 by 3 degrees or more, particularly 5 degrees. It has been found that it is preferable to soften in the above range, and it is preferable to soften in the range of 21 degrees or less, particularly 12 degrees or less.
In consideration of further improving the above effect, the thickness of the surface resin layer 15 is preferably 0.1 mm or more, particularly preferably 0.2 mm or more, and is preferably 0.8 mm or less, particularly 0.6 mm or less. Was found to be preferable.

  Further, from the results of Examples 1 to 7 and Example 8, it is understood that the same effect can be obtained even in a system in which the shore A hardness of the main body resin layer 16 is different by making the layer resin layer 15 softer than the main body resin layer 16. It was.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Surface 3 Shaping surface 4 Roughening sheet 5 Opposite surface 6 Photosensitive resin composition 7 Blade 8 First precursor layer 9 Photosensitive resin composition 10 Blade 11 Second precursor layer 12 Reinforcement sheet 13 Counter substrate 14 Opposing surface 15 Surface resin layer 16 Main body resin layer 17 Flexo resin layer 18 Laminate 19 Work table 20 Printing surface 21 Laser head 22 Carbon dioxide laser 23 Flexographic printing plate C Chuck jig L ₁ Length L ₂ Dimensions

Claims (7)

The flexo resin layer is provided with a plate-like flexo resin layer, and the flexo resin layer has a main surface resin layer having a Shore A hardness of 40 degrees or more and 50 degrees or less , and a surface exposed by being laminated on one side of the main body resin layer. is a, the saw including a soft surface layer resin layer than the body resin layer, and on the opposite side of the main body resin layer reinforced sheet is laminated, integrated flexographic printing plate.   2. The flexographic printing plate according to claim 1, wherein the surface resin layer is softer in a range of 3 degrees or more and 21 degrees or less in terms of Shore A hardness than the main body resin layer.   The flexographic printing plate according to claim 1, wherein the surface resin layer has a thickness of 0.1 mm or more and 0.8 mm or less.   4. The flexographic printing plate according to claim 1, wherein each of the main body resin layer and the surface resin layer is made of a photosensitive resin composition. Said body resin layer, and makes a photosensitive resin composition comprising the original surface layer resin layer of a material transparent to active rays for curing reaction, one side corresponding to the shape of the printing surface Fukatachimen A step of forming a first precursor layer by applying a photosensitive resin composition on which the surface resin layer is based on the shaping surface of the mold material,
A step of applying a photosensitive resin composition on which the main body resin layer is based on the first precursor layer and laminating a second precursor layer,
Laminating the reinforcing sheet to the second precursor layer, and said first and said second precursor layer, and the surface resin layer by curing reaction by irradiation of the active light through the mold member and said body resin layer Forming the laminate with the reinforcing sheet, and then peeling the laminate from the shaping surface;
The manufacturing method of the flexographic printing plate of any one of the said Claims 1 thru | or 4 containing these. The method for producing a flexographic printing plate according to claim 5 , further comprising a step of patterning at least the printing surface in correspondence with a predetermined printing pattern. The manufacturing method of a liquid crystal display element including the process of forming the liquid crystal aligning film for liquid crystal panels by flexographic printing using the flexographic printing plate of any one of the said Claim 1 thru | or 4 .

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