KR20140090542A - Flexographic printing plate and method for producing the same, and method for producing substrate for liquid crystal panel - Google Patents

Abstract

The present invention relates to a flexographic print plate which can reduce the contact pressure between the flexographic print plate and an anilox roll to reduce the wear due to the friction to be able to be used for an extended period of time and a manufacturing method thereof. The print surface (2) of the flexographic print plate (1) is roughened to make the average length of a roughness curve element (RSm) to be between 10% and 50% of the formation pitch in the surface direction (PA) of an uneven pattern of the combined anilox roll (4). The manufacturing method includes the steps of forming a photosensitive resin composite layer on a mount surface which is the basis of the print surface and hardening the photosensitive resin composite layer by emitting an activating light beam onto the photosensitive resin composite layer.

Description

TECHNICAL FIELD [0001] The present invention relates to a flexographic printing plate, a method of manufacturing the same, and a method of manufacturing a substrate for a liquid crystal panel,

The present invention relates to a flexographic printing plate which 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 of manufacturing the same, and a method of manufacturing a substrate for a liquid crystal panel using a flexographic printing plate .

It has been studied to use a printing method, in particular, a flexo printing method, in order to form a liquid crystal alignment film on an electrode formation surface of a substrate for a liquid crystal panel.

The liquid crystal alignment layer is required to be as uniform in thickness as possible, free of pinholes, and thinner.

Therefore, the printed surface (the surface that retains the ink at the time of printing) of the flexographic printing plate used for flexographic printing needs to have high retentivity for the ink serving as the base of the liquid crystal alignment film. That is, the printed surface is required to have a good maintainability capable of maintaining a uniform thickness as much as possible across the entire surface thereof without generating any cracks or breaks even if a small amount of ink is in accordance with the thickness of the liquid crystal alignment film.

In order to improve the retention of the ink on the printing surface, the printed surface may have a concavo-convex shape and the specific surface area may be increased to increase the wettability of the printing surface with the ink.

For example, Patent Documents 1 and 2 disclose a method in which a plurality of fine protrusions having a geometric planar shape such as a circular shape are formed on a printed surface so that the printed surface has a concavo-convex shape by a plurality of fine protrusions and a groove portion therebetween, Thereby improving the wettability to the ink.

Patent Documents 1 and 2 also disclose that the wettability can be arbitrarily controlled for each region in the printing surface by changing the size, distribution, arrangement, and the like of the surface of the fine protrusions.

The fine projections are formed by, for example, photolithography. That is, a layer of a photosensitive resin composition serving as a basis of a flexographic printing plate is prepared, and a mask made of a negative or positive film in which a fine pattern (dot pattern or the like) corresponding to the planar shape of the fine projections is formed is superimposed , The photosensitive resin composition is selectively cured in accordance with the pattern of the mask, and then developed to remove the uncured photosensitive resin composition, whereby a large number of fine projections are formed.

In Patent Document 3, the printed surface is roughened using an arbitrary roughening method such as etching or sandblasting, and the roughened surface of the roughened surface is roughened to have random irregularities such as fine protrusions in shape and size , Such as a satin finish surface, and the surface roughness is defined as a center line average roughness (Ra) of 1 to 5 占 퐉.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-293049 Patent Document 2: Japanese Patent No. 2933790 Patent Document 3: JP-A-2009-34913

In flexo printing, for example, a printing surface of a flexographic printing plate wound on a plate is supplied with an ink through an Anilox (ANILOX (registered trademark)) roll having an uneven pattern on the outer peripheral surface, An ink pattern corresponding to the print pattern formed on the print surface is printed on the print surface by contacting the print surface such as the electrode formation surface of the substrate for the liquid crystal panel with a predetermined pressure.

Since the anilox roll is generally formed of metal and the concavo-convex pattern on the outer circumferential surface thereof is usually formed in a shape such as a pyramid shape having a pointed tip, printing is repeated, and therefore, the flexographic printing plate contacted with the anilox roll The printed surface is gradually worn.

In order to reduce the abrasion to prolong the life of the flexographic printing plate, the irregularities on the printing surface of the flexographic printing plate are made as small as possible, and the number of contact between the convex portions of the anilox roll and the convex portions of the printing surface is increased, It is desirable to disperse the pressure as much as possible.

However, the irregularities of the printed surface formed by the photolithographic method can not be manufactured because the pitch of the irregularities in the plane direction of the irregularities is not more than 35 탆 from the limit of resolution of the mask, .

An object of the present invention is to provide a flexographic printing plate which can reduce the abrasion due to dispersion of the contact pressure with the anilox roll and can be used over a long period of time, a manufacturing method thereof, and a substrate for a liquid crystal panel And a method for producing the same.

The present invention relates to a flexographic printing plate for use in flexographic printing in which ink is supplied to an flexographic printing plate through an anilox roll having an uneven pattern on the outer circumferential surface and is formed into a flat plate having one side as a printing surface, Wherein the printed surface is roughened and the mean length (RSm) of the roughness curved elements of the printed surface is 0.1 times or more and 0.5 times or less of the pitch in the surface direction of the concavo-convex pattern of the anilox roll .

In order to solve the above problems, the inventors have found that the pitch in the surface direction of the unevenness on the printed surface described in Patent Document 3, which is not limited such that the pitch in the surface direction of the unevenness is formed by photolithography, The contact pressure between the anilox roll and the anilox roll is defined to be smaller than the pitch in the surface direction of the uneven pattern of the anilox roll so as to reduce the abrasion.

As a result, Japanese Industrial Standard JIS B0601: 2001 " Geometric Property Specification (GPS) - Surface Property: Contour Curve Method - Terms, Definitions, and Surface Property Parameters ", which specifies the average pitch in the plane direction of the concave- , The average length (RSm) of the roughness curved elements of the printing surface defined by the convex portion of the anilox roll and the printing surface It has been found that the contact pressure between the two can be dispersed as much as possible by increasing the number of contact of the convex portions to reduce the wear and prolong the life of the flexographic printing plate.

That is, when the average length (RSm) of the roughness curve elements exceeds 0.5 times the formation pitch of the concave-convex pattern of the anilox roll, the convex portion of the printed surface of the flexographic printing plate and the contact number of the convex portion of the anilox roll The effect of dispersing the contact pressure between them can not be obtained. Therefore, as the printing is repeated, the printed surface is worn and the lifetime of the flexographic printing plate is shortened.

In addition, since the concavo-convex shape of the printing surface becomes excessively large, the transfer unevenness of the ink becomes large at the time of transfer of the ink from the printing surface to the printing surface. For this reason, the ink after transfer can not be sufficiently smoothed by so-called self-leveling, and the smoothness of the surface of the liquid crystal alignment film made of ink, for example, is lowered and the thickness is made nonuniform.

On the other hand, when the average length (RSm) of the roughness curve elements is less than 0.1 times the formation pitch of the concave-convex pattern of the anilox roll, the convexo-concave shape of the printing surface is too small, The effect of improving the wettability and the amount of ink retained can not be obtained. Therefore, it is impossible to form a liquid crystal alignment film or the like having a uniform thickness, no pinhole, etc. and having a predetermined thickness.

On the other hand, the average length (RSm) of the roughness curve elements defining the average pitch in the plane direction of the concavities and protrusions on the printing surface is preferably 0.1 times or more and 0.5 times It is possible to form a liquid crystal alignment film having a uniform thickness and no pinhole and a predetermined thickness and to provide a flexographic printing plate which is small in abrasion and can be used over a long period of time.

The present invention relates to a method for producing a flexographic printing plate, which comprises the steps of preparing a mold material made of a material having transparency to an actinic light ray and having one side surface corresponding to the shape of the printing surface of the flexographic printing plate A step of laminating a layer of a photosensitive resin composition on the mold surface of the mold material so that the photosensitive resin composition is in contact with the mold surface of the mold material, and a step of passing the mold material through the mold material to irradiate an actinic light ray, A step of curing the photosensitive resin composition layer, a step of peeling the cured photosensitive resin composition layer from the mold surface of the mold material, and a step of using the peeled photosensitive resin composition layer as a flexographic printing plate.

According to the present invention, it is possible to produce a flexographic printing plate whose printing surface is defined by a specific surface state, with good productivity and low cost.

The step of forming a flexographic printing plate is a step of forming a surface of the photosensitive resin composition layer which has been peeled off from the mold surface of the mold material (a surface which was in contact with the mold surface) as a roughened print surface, It is preferable to include a step of mechanically or thermally removing the rough surface.

The step of preparing the mold material includes a step of preparing a support substrate made of a hard material having permeability to an actinic ray and a step of contacting and fixing the surface opposite to the mold surface of the mold material to the surface of the support substrate May be included.

As the photosensitive resin composition serving as a basis of the flexographic printing plate, those containing a prepolymer, a monomer having at least one ethylenic unsaturated group, and a photopolymerization initiator can be used.

The present invention is a method for producing a substrate for a liquid crystal panel, which comprises a step of forming a liquid crystal alignment film for a liquid crystal panel by flexographic printing, using the flexographic printing plate of the present invention.

According to the present invention, it is possible to produce a substrate for a liquid crystal panel having a uniform thickness, excellent thickness reproducibility, and a liquid crystal alignment film free from pinholes based on the surface shape of the printing surface described above.

According to the present invention, since the abrasion can be reduced by dispersing the contact pressure with the anilox roll at present, the flexo printing plate usable for a long period of time, the manufacturing method thereof, and the liquid crystal panel using the flexographic printing plate The present invention provides a method for manufacturing a substrate for a substrate.

1 (a) and 1 (b) are graphs showing the relationship between the convex portion of the roughened printing surface and the convex portion of the anilox roll in the flexographic printing plate of the present invention, the average length of the roughness curved elements of the printing surface RSm).
2 (a) and 2 (b) are plan views showing a method of specifying the formation pitch of the concavo-convex pattern in the plane direction for each shape of the anilox roll.
3 (a) to 3 (c) are cross-sectional views for explaining the manufacturing process of the flexographic printing plate.
4 (a) to 4 (c) are sectional views for explaining the steps subsequent to the manufacturing method of Fig. 3.
5A and 5B are cross-sectional views for explaining an example of a method of detachably fixing a roughened sheet to the surface of a flat support substrate.

1 (a) and 1 (b) are graphs showing the relationship between the convex portion of the roughened printing surface and the convex portion of the anilox roll in the flexographic printing plate of the present invention, the average length of the roughness curved elements of the printing surface RSm).

The present invention is a flexographic printing plate which is formed in a flat plate shape and whose one side is a printing surface. The average length (RSm) of the roughness curves of the printed surface is not less than 0.1 times and not more than 0.5 times the pitch in the surface direction of the uneven pattern of the anilox roll to be combined .

Further, from the roughness curve obtained by measuring the average length (RSm) of the roughness curved elements by using, for example, a scanning type confocal laser microscope in the present invention, the average length of contour curve elements in JIS B0601: 2001 As the average of the lengths Xs of the contour curve elements at the reference length as described in the following equation (1).

According to the present invention, by defining the concavo-convex shape of the roughened printing surface as described above, it is possible to form a liquid crystal alignment film or the like having uniform thickness, no pinhole, etc. and having a predetermined thickness, It is possible to provide a flexographic printing plate which can be used over a wide range.

Xs (Xs1, Xs2, ..., Xsi) of the contour curve elements of the individual convex portions 3 constituting the printing surface 2 of the flexographic printing plate 1 with reference to Fig. 1 (b) , The average length RSm of the roughness curve elements obtained by the above formula (1) exceeds 0.5 times the formation pitch P _A of the concavo-convex pattern of the anilox roll 4 to be combined The number of contact between the convex portion 3 of the printing surface 2 of the flexographic printing plate 1 and the convex portion 5 of the anilox roll 4 is reduced and the contact pressure between them is dispersed As the printing is repeated, the convex portion 3 constituting the printing surface 2 is worn out and the lifetime of the flexographic printing plate 1 is shortened.

In addition, since the size of the concavo-convex shape of the print surface 2 in the height direction becomes too large, the transfer unevenness of the ink becomes large at the time of transferring the ink from the print surface 2 to the print surface. Therefore, the ink after transfer can not be sufficiently smoothed by so-called self-leveling, so that the smoothness of the surface of the liquid crystal alignment film made of ink, for example, may be lowered or the thickness may become uneven, resulting in generation of pinholes or the like.

1 (a), the lengths Xs (Xs1, Xs2, ...) of the contour curve elements of the respective convex portions 3 constituting the printing surface 2 of the flexographic printing plate 1 The average length RSm of the roughness curved elements obtained by the above formula (1) is set to 0.5 times or less of the pitch P _{A in the} plane direction of the concavo-convex pattern of the anilox roll 4 to be combined The number of contact between the convex portion 3 of the printing surface 2 of the flexographic printing plate 1 and the convex portion 5 of the anilox roll 4 is increased so that the contact pressure between them It can be dispersed in the convex portion 3, so that the wear can be reduced and the life of the flexographic printing plate 1 can be prolonged.

However, when the average length RSm of the roughness curve elements is less than 0.1 times the pitch P _{A in the} surface direction of the concave-convex pattern of the anilox roll 4 to be combined, The size in the height direction becomes excessively small and the effect of improving the wettability of the printing surface 2 with the ink and the amount of ink retained by forming the unevenness can not be obtained. For this reason, there arises a problem that a uniform thickness, no pinholes, and the like, and furthermore, a liquid crystal alignment film having a predetermined thickness can not be formed.

Therefore, the average length RSm of the roughness curve elements is limited to 0.1 times or more of the pitch P _{A in the} surface direction of the concave-convex pattern of the anilox roll 4 to be combined. This makes it possible to form a liquid crystal alignment film or the like having uniform thickness and no pinhole or the like and having a predetermined thickness.

In order to further improve this effect, it is preferable that the average length (RSm) of the roughness curve elements is 0.3 times or more and 0.4 times or less of the formation pitch (P _A ).

The specific size of the average length RSm is not particularly limited. The size may be set to the predetermined magnification with respect to the formation pitch P _A of the anilox roll 4 to be combined.

Not general form of rocks roll 4 the pitch (P _A) is about 21~141 ㎛.

Therefore, the average length RSm of roughness curve elements of the printed surface 2 of the flexographic printing plate 1 combined with the anilox roll 4 having the formation pitch P _A of 63.5 占 퐉 is 6.35 占 퐉 or more , And 31.75 mu m or less.

2 (a) and 2 (b) are plan views showing the method of specifying the pitch of the concavo-convex pattern in the plane direction for each shape of the anilox roll 4.

For example, referring to FIG. 2A, each convex portion 5 constituting the concavo-convex pattern is formed into a square pyramid shape having a square bottom face, and one diagonal line of the bottom face is formed as an anilox roll Called anilox roll 4 of diamond pattern, which is arranged at equal intervals in a direction parallel to the circumferential direction (indicated by a solid line in the figure) of the substrate 4 and another diagonal line perpendicular to the circumferential direction, of the time, and as the formation pitch (P _a), the distance between the apex of the raised portion (5) which in the circumferential direction perpendicular to the width direction, adjacent to each other.

2 (b), each convex portion 5 is formed into a hexagonal conical shape whose bottom face is a regular hexagon, and one diagonal line of the bottom face is formed in the circumferential direction of the anilox roll 4 In the case of the anilox roll 4 of the so-called honeycomb pattern in which the width direction orthogonal to the longitudinal direction (indicated by the solid line arrows) and the other two diagonal lines are arranged at equal intervals with the direction of 30 DEG with respect to the circumferential direction, wherein the distance between the apex of the raised portions (5) adjacent in the direction of 30 °, with respect to the circumferential direction and to the pitch (P _a).

Although not shown, one diagonal line of the hexagonal cone-shaped convex portion 5 is formed in a direction parallel to the circumferential direction of the anilox roll 4 and two diagonal lines different from each other by 60 degrees with respect to the circumferential direction directing the like in the case of rocks roll 4 is not in a honeycomb pattern arranged at intervals, the circumferential direction with projections (5) wherein the pitch (P _a), the distance between the vertex of adjoining in the transverse direction, which is perpendicular do.

In order to make the printing surface 2 of the flexographic printing plate 1 to have the concavo-convex shape satisfying the range of the average length RSm of the roughness curved elements, in the method of producing a flexographic printing plate of the present invention The mold surface of the mold material corresponding to the surface 2 may be formed into a concavo-convex shape satisfying the above range.

Further, in order to form the mold surface with the concavo-convex shape satisfying the above-mentioned range, when the mold surface is formed by roughening by pressurizing sheet molding using an emboss roll to be described later, the outer circumferential surface of the emboss roll It may be formed into a concavo-convex shape satisfying the range.

Specifically, for example, when the emboss roll is a metal roll, it may be patterned by etching, shot blasting, laser engraving, and the like, or in the case of a rubber roll, by patterning, polishing, The outer peripheral surface can be formed into a concavo-convex shape by etching, micro-mixed material, or the like.

For example, when the outer circumferential surface of the metal roll is formed into a concavo-convex shape by shot blasting, the diameter (F600 or more) of the blast powder to be used and the blast time are set so that the average length (RSm) Control.

The flexographic printing plate of the present invention can be produced by the production method of the present invention. Thus, a flexographic printing plate whose printing surface is defined by a specific surface state can be manufactured with good productivity and low cost.

3 (a) to 3 (c) and 4 (a) to 4 (c) are cross-sectional views for explaining steps of manufacturing a flexographic printing plate.

Referring to Fig. 3 (a), in the manufacturing method of this example, at first, the photosensitive resin composition is made of a hard material such as glass or a hard resin such as an acrylic resin, a polycarbonate resin, or a polyester resin, A support substrate 6 having transparency to an active ray such as ultraviolet rays is prepared.

In the figure, the upper surface 7 of the support substrate 6 is provided with a roughened surface sheet 8 having a roughened surface 8 having a concavo-convex shape with one side corresponding to the shape of the printing surface of the flexographic printing plate 9 while the opposite face 10 is in contact with the surface 7 with the face 10 opposite to the opposite face 10 above the face 8 facing downward. As shown by the arrows of the dotted line, from the one end thereof to the other end thereof in order.

In the drawing, the irregularities constituting the forming surface 8 are greatly emphasized for clarity. However, since the actual irregularities do not affect the shape of the liquid crystal alignment film to be printed or the like, the roughness curved elements (RSm) of the surface roughness (RSm) of the rough surface sheet 9, which is as small as can not be discriminated by comparison with the size of the rough surface sheet 9 shown in the figure.

As the roughened sheet 9, for example, polyethylene (PE), polypropylene (PP), thermoplastic polyurethane elastomer (TPU), polyethylene terephthalate (PET), tetrafluoroethylene / hexafluoropropylene copolymer Of the surface of the sheet having transparency to an actinic ray is formed into a roughened surface by pressurizing sheet molding or the like using an embossing roll.

Such pressure sheet forming has an advantage that it is easy to continuously and mass-produce even a large-area roughened sheet 9 corresponding to a large-sized liquid crystal display element, for example.

In addition, a relatively thin (for example, about 150 탆 or less) roughened sheet 9 made of a relatively soft thermoplastic resin such as PE, PP, or TPU has a weak viscosity, It may be difficult to uniformly adhere to the surface 7 without wrinkles.

In this case, a reinforcing sheet made of, for example, PET or the like and having permeability to an actinic ray may be bonded to the opposite surface 10 of the roughened sheet 9.

The roughened sheet 9 is formed on the roughened sheet 9 in such a manner that the roughed sheet 9 is supported by the shear force when the liquid photosensitive resin composition is spread on the roughened sheet 9 or by the shrinkage force upon curing of the photosensitive resin composition, In order to prevent displacement of the position with respect to the substrate 6 and facilitate the replacement of the rough surface sheet 9 after use, It is preferable to detachably fix it on the surface 7 of the base 6.

(i) detachably adhered and fixed to the surface 7 of the support substrate 6 via a weakly adhesive layer made of a material having permeability to an actinic ray.

(ii) a suction groove is formed on the surface of the support substrate, and is vacuum-sucked through the suction groove to be detachably fixed to the surface.

(iii) is pressed and fixed to the surface of the support substrate in a state in which it is extended between a pair of chucks spaced apart from each other in a plane direction of the support substrate 6.

The weakly adhesive layer used for the adhesive fixation of the adhesive layer (i) is preferably a layer composed of various pressure sensitive adhesives having weak adhesiveness to the forming materials of the support substrate 6 and the roughened sheet 9, Any of which can be adopted. The weakly adhesive layer is formed by applying a pressure-sensitive adhesive to at least one of the surface 7 of the support substrate 6 and the opposite surface 10 of the roughened sheet 9 by various coating methods such as spray coating do.

After the weakly adhesive layer is formed on the surface 7 of the support substrate 6 and / or the opposite surface 10 of the roughened sheet 9, the weakly adhesive layer is formed as shown in Fig. 3 (a) Likewise, when the roughened sheet 9 is superposed in order from one end of the surface 7 of the supporting substrate 6 to the other end, taking care not to allow air to enter between the opposite surface 10 and the surface 7 , The rough surface sheet 9 can be fixed on the surface 7 by the adhesive force of the weakly adhesive layer.

In order to remove the roughened sheet 9 from the surface 7, the roughened sheet 9 is cut from the other end of the support substrate 6 at one end, for example, as opposed to the arrow in Fig. 3 (a) It may be peeled off in order, against the adhesive force of the weakly adhesive layer.

the surface 7 of the support substrate 6 is smoothly finished and the suction grooves are formed on substantially the entire surface of the surface 7 in order to perform the suction fixation of the surface (ii). The suction groove is connected to a vacuum system including a vacuum pump or the like.

A vacuum system is operated in a state in which the rough surface sheet 9 is superimposed on the surface 7 of the support substrate 6 with the opposite surface 10 facing downward And the surface of the roughened sheet 9 can be fixed on the surface 7 by vacuum suction through the suction groove.

In order to remove the fixed rough sheet 9 from the surface 7, the vacuum system may be stopped or the connection between the vacuum system and the suction groove may be cut off.

5 (a) and 5 (b) are cross-sectional views illustrating the method of press-fitting in (iii).

In this press-fitting method, for example, a pair of chucks 9, which hold two mutually parallel sides of a roughened sheet 9 formed in a rectangular shape in correspondence with the shape of the screen of a liquid crystal display element, The jig C is prepared.

The length L ₁ between the two sides of the rough sheet 9 is set to be longer than the dimension L ₂ between the corresponding two sides of the support substrate 6 formed in the same rectangular shape, The side is held by the chuck jig C over its entire length. The rough surface sheet 9, although not shown, holds the surface 8 in a state in which the surface 8 faces upward.

By arranging the chuck jig C at a distance larger than the dimension L ₂ of the supporting substrate 6, the rough-surfaced sheet 9 is placed between the moving jig C without loosening 5 (a)).

Subsequently, in this state, the chuck jig C is moved downward in the drawing, whereby the roughened sheet 9, which is placed between the chuck jig C, is folded as shown by white arrows in Fig. 5 (a) As shown in Fig. 5 (b), the rough surface sheet 9 is pressed against the surface 7 of the support substrate 6 ). ≪ / RTI >

In order to remove the fixed roughened sheet 9 from the surface 7, the roughened sheet 9 is folded on the entire surface of the pair of chuck jigs C in the opposite direction to the arrow in Fig. 5 (a) 7).

Referring to Fig. 3 (b), in the manufacturing method of this example, on any one of the above-described methods, on the surface 8 of the roughened sheet 9 fixed on the surface 7 of the support substrate 6 , And a predetermined amount of the liquid photosensitive resin composition 11 is supplied.

The photosensitive resin composition 11 is sandwiched between the roughened sheet 9 and the reinforcing film 12 serving as a reinforcing layer so that the supporting substrate 6 (see Fig. 3 (b) The layer 13 of the photosensitive resin composition is spread on the surface 8 of the roughened sheet 9 while taking care not to allow air to enter therebetween from one end to the other end of the surface 7 of the photosensitive resin composition And the reinforcing film 12 is laminated thereon.

3 (c), the opposing face 15 of the counter substrate 14 is brought into contact with the reinforcing film 12.

The opposing face 15 of the opposing substrate 14 is held parallel to the surface 7 while keeping a predetermined gap therebetween and the opposing substrate 14 as shown by a black arrow in FIG. The layer 13 is pressed against the surface 8 of the roughened sheet 9 by pressing in the direction of the support substrate 6. [

Then, in this state, the layer 13 is passed through the support substrate 6 and the roughened sheet 9 and exposed by the actinic ray LB as indicated by the solid line arrow in Fig. 3 (c) , The photosensitive resin composition (11) forming the layer (13) is subjected to a curing reaction.

The distance between the surface 7 of the support substrate 6 and the opposing surface 15 of the counter substrate 14 is determined by adding the thickness of the roughened sheet 9 to the thickness of the flexographic printing plate to be produced .

Further, the counter substrate 14 can be formed of any material such as metal, glass, and hard resin.

Particularly, the counter substrate 14 is formed of a material having the same permeability as that of the support substrate 6, and the reinforcing film 12 is also made of the same material as that of the roughened sheet 9, And the layer 13 of the photosensitive resin composition may be exposed to the crosslinking reaction by an actinic ray from the side of the counter substrate 14 as well.

4 (a) and 4 (b), the laminate 16 of the reinforcing film 12, the crosslinked layer 13 and the roughened sheet 9 is laminated on the supporting substrate 6 The reinforcing film 12 is taken out from between the opposing substrates 14 and is placed upside down on the work table 17 with the reinforcing film 12 downward.

When the roughened sheet 9 is peeled in order from one end of the layered body 16 to the other end as indicated by one-dot chain line in Fig. 4 (b) Convex shape of the surface 8 of the roughened sheet 9 is transferred to form a roughened printed surface 2.

Subsequently, as shown in Fig. 4 (c), a carbon dioxide gas laser 19 or the like is scanned from the laser head 18 onto an area other than the area corresponding to the printing pattern on the printing surface 2 By irradiating, the irregularities on the surface are thermally removed. Thus, the printing surface 2 is patterned into a predetermined printing pattern, and the flexographic printing plate 1 is completed.

The photosensitive resin composition can be cured by an actinic ray such as ultraviolet rays and further has appropriate rubber elasticity suitable for use in, for example, flexo printing after curing, and is contained in the ink used for printing, And a resin composition which is capable of forming a cured product excellent in solvent resistance to a solvent to be used for cleaning of the resin composition.

Such photosensitive resin compositions include, but are not limited to, those containing a prepolymer having an 1,2-butadiene structure and having an ethylenic double bond at the terminal, an ethylenically unsaturated monomer, and a photopolymerization initiator have.

As the photopolymerization initiator, benzoin alkyl ethers are preferable. Particularly, the content of benzoin, which causes yellowing of the printing plate resin by reaction with visible light from a fluorescent lamp or the like, is preferably 500 ppm or less of the total amount of the photosensitive resin composition Lt; / RTI > This makes it possible to obtain a printing plate for printing resin excellent in light fastness not yellowing in a short period of time.

The reinforcement film 12 may be formed of a material such as polyethylene (PE), polypropylene (PP), thermoplastic polyurethane (TPU), polyethylene terephthalate (PET), tetrafluoroethylene hexafluoro A sheet made of a thermoplastic resin such as a propylene copolymer (FEP) and having transparency to an actinic ray can be used.

The present invention is a method for producing a liquid crystal panel substrate, which comprises a step of forming a liquid crystal alignment film for a liquid crystal panel by flexographic printing using a flexographic printing plate.

According to the present invention, it is possible to produce a substrate for a liquid crystal panel having a uniform thickness, excellent thickness reproducibility, and further comprising a liquid crystal alignment film free of pinholes. In addition, the wear of the flexographic printing plate is reduced on the basis of the surface shape of the printing surface described above, and it becomes possible to continue the repeated use of a single flexographic printing plate over a long period of time compared with the present.

The other steps of the above production method can be carried out in the same manner as in the conventional method.

That is, after a transparent electrode layer corresponding to a predetermined matrix pattern or the like is formed on one side of a transparent substrate such as a soda-lime glass substrate, a liquid crystal alignment film is formed by flexographic printing using the flexographic printing plate of the present invention, The surface is further subjected to orientation treatment, if necessary, by rubbing or the like to produce a substrate for a liquid crystal panel.

In addition, two liquid crystal panel substrates were prepared, the liquid crystal material was sandwiched between the transparent electrode layers and fixed to each other, and a polarizing plate was further disposed on both sides of the laminate as required, A panel is manufactured.

The present invention is not limited to the examples of the drawings described above. For example, the reinforcing film 12 may be omitted. Further, instead of pressing the layer of the photosensitive resin composition in the direction of the support substrate by the counter substrate, the layer may be spread by a roller or the like of the roughened sheet to make the thickness constant.

In addition, various modifications can be made without departing from the gist of the present invention.

Example

(Example 1)

(Roughened sheet)

As the roughened sheet, a sheet of TPU (Silkrone (registered trademark) SNESS80-150 占 퐉 manufactured by Okura Kogyo Co., Ltd.) in which a PET sheet having a thickness of 100 占 퐉 was bonded to one side as a reinforcing sheet, And the surface of the TPU exposed on the opposite side was formed as a roughened surface by pressure sheet formation using an emboss roll. Such a roughened sheet has transparency to ultraviolet rays as an active ray.

From the roughness curve obtained by measuring the average length (RSm) of the roughness curved elements of the molding surface using a scanning type confocal laser microscope (LEXT (registered trademark) OLS (registered trademark) 3100, manufactured by Olympus Corporation) The average length Xs of the contour curve elements in the reference length as described in Section 4.3.1 of JIS B0601: 2001 "Average length of contour curve elements" was 9.0 μm as determined by the above formula (1). The reference length was 270 탆.

(Preparation of flexo printing plate)

3 (a) to 3 (c), a transparent transparent glass plate having ultraviolet transmittance as a support substrate 6 and an apparatus for producing a printing resin original plate having a counter substrate 14 And the opposite surface 10 is brought into abutment with the surface 7 so that the rough surface 8 is above the opposite surface 10 and the opposite surface 10 is below the surface 7. [ Lt; RTI ID = 0.0 > detachable < / RTI > through a layer of spray adhesive.

Subsequently, a predetermined amount of an ultraviolet curable liquid photosensitive resin composition (NK resin manufactured by Sumitomo Rubber Kogyo Co., Ltd.) is supplied on the mold surface 8 to form a roughened sheet 9 and a reinforcing layer (BF / CF manufactured by Sumitomo Rubber Industries, Ltd.) 12 as shown by the one-dot chain line in Fig. 3 (b) The layer 13 of the photosensitive resin composition is formed by spreading on the mold surface 8 of the roughened sheet 9 while taking care not to allow air to enter between the one end of the photosensitive resin composition 7 and the other end , And a reinforcing film 12 was laminated thereon.

Subsequently, the opposing face 15 of the counter substrate 14 was brought into contact with the reinforcing film 12.

The counter substrate 14 is held on the support substrate 6 as shown by a black arrow in FIG. 3 (c) while keeping the opposing face 15 parallel to the surface 7 with a predetermined gap therebetween. So that the layer 13 was pressed onto the molding surface 8 of the roughened sheet 9.

Then, in this state, the layer 13 is passed through the support substrate 6 and the roughened sheet 9 and exposed by ultraviolet rays as indicated by the solid line arrow in Fig. 3 (c) ) Was cured and reacted with the photosensitive resin composition (11). As the light source, a UV light source manufactured by Philips was used.

4 (a) and 4 (b), the reinforcing film 12, the crosslinked layer 13 and the layered product 16 of the roughened sheet 9 are laminated on the supporting substrate 6, And the reinforcing film 12 is placed on the work table 17 with the reinforcing film 12 downward.

4 (b), the roughened sheet 9 is peeled in order from one end of the layered body 16 to the other end of the layered structure 16, Was used as the printing surface 2 in which the convexo-concave shape of the forming surface 8 of the roughened sheet 9 was transferred and roughened.

Subsequently, as shown in Fig. 4 (c), an area other than the area corresponding to the printing pattern of the printing surface 2 is irradiated with the carbon dioxide gas laser 19 from the laser head 18, , Whereby the printing surface 2 was patterned into a predetermined printing pattern to produce the flexographic printing plate 1. [

The patterning conditions were as follows: output of a carbon dioxide gas laser: 400 W × 2 beams, beam diameter: 20 μm, feed pitch: 60 μm, and feed rate: 140 cm / sec.

After the patterning, the contamination by the flux-breaking droplet resin was cleaned using a KS-HG thinner under the trade name of a product manufactured by Daiyo Kagaku Co., Ltd., and sufficiently dried.

From the roughness curve obtained by measuring the average length RSm of the roughness curved elements of the printing surface 2 of the flexographic printing plate 1 using the scanning type confocal laser microscope, Of the length (Xs) determined by the above formula (1) as 9.0.

From the above results, it was confirmed that the concavo-convex shape of the printing surface 2 of the flexographic printing plate 1 faithfully copied the convexo-concave shape of the convex surface 8 of the roughened sheet 9.

The flexographic printing plate 1 was obtained in the same manner as in Example 1 except that the anilox roll 4 having a diamond pattern shown in FIG. 2A and having a forming pitch P _A of 63.5 μm (manufactured by Asahi Kasei Imperialties Co., Ltd.) # 400]. The mean length (RSm) of the roughness curve elements was 0.14 times the formation pitch (P _A ).

(Examples 2 and 3, Comparative Examples 1 and 2)

The embossing roll for roughening the surface of the TPU exposed on the side opposite to the side bonded with the reinforcing sheet of the same sheet of the TPU as used in Example 1 by pressure sheet formation was changed, A rough-surfaced sheet (9) having the average length (RSm) of the roughness curved elements as shown in the following Table 1 was prepared.

A flexographic printing plate 1 was produced in the same manner as in Example 1 except that each of the roughened sheets 9 was used.

The average length RSm of roughness curved elements of the printing surface 2 of the flexographic printing plate 1 was obtained in the same manner as described above. As shown in the following Table 1, the printing of the flexographic printing plate 1 It was confirmed that the concavo-convex shape of the surface 2 was faithfully copied from the convexo-concave shape of the concave surface 8 of the roughened sheet 9.

(practical examination)

(Flexo printing)

A flexographic printing press Format A45 of nakan Techno Co., manufactured for liquid crystal alignment layer, each of the embodiments, comparison a flexographic printing plate a, which is not rocks Roll # 400 (the pitch (P _A above prepared in Reference Example): 63.5 Mu m).

Then, a varnish for a liquid crystal alignment film (trade name: OFFTOMA (registered trademark) AL60702 manufactured by JSR Corporation, contact angle with respect to soda lime glass substrate: 30 DEG) was flexo-printed on a soda lime glass substrate having a thickness of 0.7 mm, Lt; 0 > C for 30 minutes to preliminarily dry the varnish to form a liquid crystal alignment film.

The conditions for the flexographic printing were set so that the thickness of the liquid crystal alignment layer after preliminary drying was 1000 angstroms.

(Initial thickness evaluation)

The thickness of the liquid crystal alignment film after preliminary drying was measured and the initial thickness was evaluated based on the following criteria.

○○: Thickness was exactly 1000 Å.

?: Thickness was other than 1000 Å, and was within 1000 ± 100 Å.

X: Thickness was other than 1000 ± 100 Å.

(Wear evaluation)

In Examples 1 to 3 and Comparative Example 2 in which the evaluation of the initial thickness was 0 or 0, continuous printing of 50,000 sheets was carried out under the same conditions as above to wipe out the flexographic printing plate so that the thickness of the liquid crystal alignment layer was 900 Å And the abrasion reduction effect of the flexographic printing plate was evaluated based on the following criteria. In Comparative Example 1 in which the evaluation of the initial thickness was negative, no wear was evaluated.

X: The thickness of the liquid crystal alignment layers up to 50,000 sheets was not lower than 900 Å. Very good abrasion reduction effect.

○○: The thickness of the liquid crystal alignment layer was less than 900 Å in the range of 40,000 or more and less than 50,000 sheets. Good abrasion reduction effect.

?: The thickness of the liquid crystal alignment film was less than 900 占 within the range of more than 30,000 sheets and less than 40,000 sheets. Normal abrasion reduction effect level.

X: The thickness of the liquid crystal alignment film was less than 900 Å in the range of less than 30,000 sheets. Bad abrasion reduction effect.

(Total judgment)

From the results of the initial thickness evaluation and the abrasion evaluation, whether or not the flexographic printing plate was good was judged by the following criteria.

○ ○ ○: Initial thickness evaluation is ○○ and wear resistance is ○○○ or ○○.

○ ○: Initial thickness evaluation is ○ ○, wear resistance is ○, initial thickness evaluation is ○, and abrasion resistance is ○ ○ ○ or ○○.

?: Initial thickness evaluation was?, And abrasion resistance was?.

X: Any one or both sides x.

Table 2 shows the above results.

From the results of the comparison of the Table 2, Example 1, and the average length of the curved elements roughness of the printing surface of the flexographic printing plate (RSm) is 0.1 of the concave-convex pattern of not rocks rolls combined, if the pitch (P _A) is formed in a direction The effect of improving the wettability of the printing surface with respect to the ink and the amount of ink retained by forming the unevenness can not be obtained, and a liquid crystal alignment film or the like having a predetermined initial thickness Can not be formed.

From the results of Comparative Example 2, when the average length (RSm) of the roughness curved elements exceeds 0.5 times the formation pitch (P _A ), the convex portion of the printing surface of the flexographic printing plate and the convex portion of the printing surface of the anilox roll The number of negative contacts is reduced, and the effect of dispersing the contact pressure between them is not obtained, so that the printed surface is easily worn and the lifetime of the flexographic printing plate is shortened.

On the contrary, from the results of Examples 1 to 3, it was found that by setting the average length (RSm) of the roughness curved elements within the range of 0.1 to 0.5 times the formation pitch (P _A ) Further, it has been found that a liquid crystal alignment film or the like having a predetermined thickness can be formed and a flexographic printing plate usable for a long period of time can be obtained because the abrasion is small.

From the results of Examples 1 to 3, it was found that the average length (RSm) of the roughness curved elements was preferably 0.3 times or more and 0.4 times or less of the formation pitch (P _A ) in order to improve the effect.

1: Flexo printing plate, 2: Printing surface, 3: Convex part, 4: Anilox roll, 5: Convex part, 6: Supporting substrate, 7: Surface, 8: Molded surface, 9: A laser beam is irradiated to the surface of the workpiece while the laser beam is applied to the surface of the workpiece. Jig, P _A : formation pitch, Xs (Xs1, Xs2, ... Xsi): length of contour curve element

Claims (6)

As a flexographic printing plate used for flexographic printing in which ink is supplied to the flexographic printing plate through an anilox roll provided with an uneven pattern on the outer peripheral surface thereof,
Wherein an average length (RSm) of roughness curved elements of the printing surface is set to a value obtained by dividing the average length (RSm) of an uneven pattern of the anilox roll, Is not less than 0.1 times and not more than 0.5 times the formation pitch in the plane direction. A method for producing a flexographic printing plate according to claim 1,
A step of preparing a mold material made of a material having transparency to an actinic light ray and having a one side surface corresponding to the shape of the printing surface of the flexographic printing plate,
A step of laminating a layer of the photosensitive resin composition on the mold surface of the mold material so that the photosensitive resin composition is in contact with the mold surface of the mold material,
A step of irradiating an active ray through a mold material to cure the photosensitive resin composition layer by a curing reaction,
A step of peeling the cured photosensitive resin composition layer from the mold surface of the mold material, and
Step of making the exfoliated photosensitive resin composition layer as a flexographic printing plate
Wherein the flexographic printing plate comprises a base material. The process for producing a flexographic printing plate according to claim 2, wherein the step of forming a flexographic printing plate comprises the steps of: peeling the surface of the photosensitive resin composition layer from the mold surface (the surface which was in contact with the mold surface) And removing the roughened surface of the printing surface other than the area mechanically or thermally. The method according to claim 2, wherein the step of preparing the mold material comprises:
Preparing a support substrate made of a hard material and having permeability to an actinic ray;
A step of contacting and fixing the surface of the support substrate opposite to the surface of the mold material to the mold surface,
Wherein the flexographic printing plate comprises a base material. The method for producing a flexographic printing plate according to any one of claims 2 to 4, wherein as the photosensitive resin composition, a composition comprising a prepolymer, a monomer having at least one ethylenic unsaturated group, and a photopolymerization initiator is used. A process for producing a substrate for a liquid crystal panel, which comprises a step of forming a liquid crystal alignment film for a liquid crystal panel by flexographic printing using the flexographic printing plate according to claim 1.

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