JP5346695B2 - Rubbing method and apparatus, and alignment film and optical member manufacturing method - Google Patents

Description

  The present invention relates to a rubbing method and apparatus, and an alignment film and an optical member manufacturing method, and particularly when an optical member used in a liquid crystal display device is manufactured, the alignment film forming layer is sufficiently rubbed while suppressing dust generation. Related to technology.

  Various optical members are used in the liquid crystal display device. For example, an optical compensation film for expanding the viewing angle is used as a polarizing plate member. In general, this optical compensation film is formed by applying an orientation coating solution on the surface of a transparent flexible belt-like flexible support to form an orientation film forming layer, and then rubbing the surface to form an orientation film. Form. And it manufactures by apply | coating and drying a liquid crystalline coating liquid on alignment film, forming a liquid-crystal layer, and making it harden | cure after that.

  Rubbing is a typical method for aligning liquid crystal molecules. An alignment film forming layer is formed on the surface of the web, and a rubbing roller on which a rubbing cloth is wound is rotated at high speed on the surface of the alignment film forming layer. And is done by rubbing.

  By the way, in recent years, it has been necessary to reduce the number of bright spots and to reduce the bright spot size, which influence the deterioration of the display quality of the liquid crystal display apparatus, by increasing the brightness and definition of the liquid crystal display apparatus. As a cause of the bright spot defect, there may be a case where it is caused by a surface defect caused by an orientation failure due to insufficient or unstable rubbing or a case where dust is rubbed.

  Conventional techniques for rubbing the alignment film forming layer include, for example, Patent Documents 1 to 6. In Patent Document 1, the alignment film forming layer is conditioned to eliminate traces of partial stretching of the alignment film forming layer, thereby reducing surface defects caused by poor alignment. In Patent Document 2, a support body humidity adjusting means is provided on the upstream side of the rubbing apparatus to control the moisture content of the support body and to control the atmospheric humidity around the rubbing apparatus to reduce surface defects caused by poor alignment. In Patent Document 3, fluid pressure is applied from the back side of the support during rubbing, and the support is pressed against the rubbing roller to reduce surface defects due to poor alignment. In Patent Document 4, by varying the number of rotations of the rubbing roller in two steps, variations in alignment film regulating force are controlled to reduce surface defects caused by alignment defects. Patent document 5 reduces the surface defect resulting from an orientation defect by making the pile thread | yarn of a rubbing cloth into a predetermined inclination | tilt angle (26-40 degrees with respect to the perpendicular line Z). Patent Document 6 discloses that the rubbing cloth is dust-removed by discharging the rubbing cloth after rubbing with ion wind.

JP 2003-329833 A JP 2006-259151 A JP 2006-267919 A JP 2009-003368 A Registered Utility Model No. 3032820 JP 2009-031735 A

  As can be seen from Patent Documents 1 to 5, conventionally, the rubbing technique has been improved in consideration of prevention of orientation failure, and surface defects caused by orientation failure are suppressed by improving the rubbing performance, thereby optical compensation. Bright spot defects can be reduced when the film is produced.

  However, if rubbing is performed strongly so as not to cause alignment failure, dust generation during rubbing increases, and there is a problem that bright spot defects due to dust increase. As in Patent Document 6, by removing the rubbing cloth, the bright spot defect caused by the dust can be reduced to some extent, but it is not a fundamental solution unless dust generation during rubbing is suppressed.

  The present invention has been made in view of such circumstances, and a rubbing method and apparatus, an alignment film, and an optical device capable of simultaneously solving both a bright spot defect caused by orientation failure and a bright spot defect caused by dust. It aims at providing the manufacturing method of a member.

In order to achieve the above object, claim 1 of the present invention forms a support body with the rubbing cloth material by bringing the rubbing cloth material into contact with a continuously running support body on a rotating rubbing roller. in the rubbing process for forming the rubbed by alignment film alignment material layer which is, the rubbing cloth material, with the pile yarns is formed being woven into a base fabric composed of warp and weft of the ground fabric structure, the By changing the stiffness of the pile yarn, the degree of deflection during rubbing of the pile yarn is determined based on the total length A of the pile yarn before rubbing, and the base in the rubbing in which a rubbing load is applied to the pile yarn. When expressed as a ratio (B / A) × 100 to the length B from the cloth surface to the alignment film forming layer surface, rubbing is performed in a state where the ratio is set in a range of 60 to 90%. Rabbi To provide a grayed way.

  The inventor has intensively studied measures for achieving both suppression of bright spot defects caused by orientation failure and suppression of bright spot defects caused by dust generated during rubbing. As a result, it was found that by properly setting the degree of deflection during rubbing of the pile yarn of the rubbing cloth wound around the rubbing roller, orientation failure does not occur and dust generation can be remarkably suppressed. .

  Here, the degree of deflection during rubbing of the pile yarn is determined by the alignment film formation from the entire length A of the pile yarn before rubbing and the base fabric surface of the rubbing cloth material in which rubbing load is applied to the pile yarn. Since the ratio (B / A) × 100 with the length B to the layer surface is smaller, the smaller the ratio is, the greater the degree of deflection is.

  According to the first aspect of the present invention, the degree of deflection of the pile yarn during rubbing is oriented from the total length A of the pile yarn before rubbing and the base fabric surface in the rubbing where the rubbing load is applied to the pile yarn. When expressed as a ratio (B / A) × 100 to the length B to the film forming layer surface, the rubbing was performed in a state where the ratio was set in the range of 60 to 90%, resulting in poor alignment. Both bright spot defects and bright spot defects caused by dust can be solved simultaneously.

  If the ratio is less than 60%, the contact area of the pile yarn with the alignment film forming layer becomes large, so that the alignment performance is improved, but the dust generation during rubbing increases rapidly. Accordingly, when the optical member is manufactured, the bright spot defects due to dust increase even if the bright spot defects due to the alignment failure can be suppressed, so that the total bright spot defects increase.

  On the other hand, if the ratio exceeds 90%, the contact area of the pile yarn with respect to the alignment film forming layer becomes small, so that dust generation is suppressed but alignment failure occurs. Therefore, when the optical member is manufactured, even if the bright spot defects caused by the dust can be suppressed, the bright spot defects caused by the alignment failure increase, so that the total number of bright spot defects increases.

  The rubbing method according to claim 1, wherein the degree of deflection of the pile yarn is preferably set within the ratio range by adjusting the relative humidity in the rubbing chamber in which the rubbing is performed to change the stiffness of the pile yarn.

  This is based on the knowledge that the stiffness of the pile yarn varies significantly depending on the moisture of the pile yarn. The humidity of the rubbing chamber is increased to increase the moisture of the pile yarn. When it is reduced and the moisture content of the pile yarn decreases, it becomes difficult to bend. Therefore, by appropriately adjusting the humidity of the rubbing chamber, the degree of bending of the pile yarn can be set within the ratio range. Specifically, it is preferable to adjust the relative humidity in the rubbing chamber to a range of 10 to 50%.

  In the rubbing method according to claim 1, it is preferable that the degree of deflection of the pile yarn is set within the ratio range by coating the surface of the pile yarn with a resin to change the stiffness of the pile yarn.

  In this method, the degree of deflection of the pile yarn is set within the ratio range by changing the rigidity of the pile yarn itself. With this method, the degree of deflection of the pile yarn during rubbing can be appropriately set without being affected by the humidity environment of the rubbing chamber.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the humidifying step of humidifying the front chamber before the rubbing to apply moisture to the support, and the rubbing chamber to be rubbed in the front chamber A dehumidifying step for dehumidifying to be less than the relative humidity of the substrate and preventing the moisture of the rubbing cloth material from rising due to moisture brought into the rubbing chamber from the front chamber by transporting the support. Is preferred.

  According to claim 5 of the present invention, the trace of partial stretching of the alignment film forming layer can be eliminated by humidifying the rubbing front chamber and applying moisture to the alignment film forming layer. Orientation defects can be suppressed. However, when the support body humidified in the front chamber is directly transferred to the rubbing chamber, the relative humidity in the rubbing chamber increases. As a result, the moisture content of the rubbing cloth wound around the rubbing roller is increased, and the degree of bending of the pile yarn during rubbing is increased, so that dust generation is increased. Further, when the alignment film forming layer that has been humidified in the front chamber is rubbed, the alignment film forming layer is easily damaged.

  Therefore, in the present invention, the rubbing chamber is dehumidified so that the rubbing chamber to be rubbed is smaller than the relative humidity in the front chamber, and the rubbing cloth material is brought into the rubbing chamber by the transport of the support from the front chamber. Since the dehumidification process which prevents that the water | moisture content rises was provided, the dust generation at the time of rubbing can be suppressed effectively.

  Thereby, it is possible to simultaneously solve both the bright spot defect caused by the orientation failure and the bright spot defect caused by the dust.

  In the rubbing method according to claim 5, it is preferable that humidification is performed so that the relative humidity of the front chamber is 55% or more and 80% or less, and dehumidification is performed so that the relative humidity of the rubbing chamber is 10 to 50%.

  6. The rubbing method according to claim 5, wherein only the narrow gap through which the support can pass is left between the humidifying step in the front chamber and the dehumidifying step in the rubbing chamber. It is preferable to provide a damp feeling prevention step for preventing moisture from being brought into the rubbing chamber from the front chamber by partitioning the front and rear chambers.

  6. The rubbing method according to claim 5, further comprising an atmospheric pressure control step for making the atmospheric pressure in the rubbing chamber higher than the atmospheric pressure in the front chamber.

  This makes it difficult for moisture from the front chamber that gives moisture to the support to be brought into the rubbing chamber, and the rubbing chamber can be accurately controlled to an appropriate humidity, so that dust generation during rubbing can be more effectively suppressed. Can do. In this case, it is better to use the wet feeling prevention process and the atmospheric pressure control process in combination.

According to a ninth aspect of the present invention, in order to achieve the above object, the rubbing cloth is wound and the rubbing roller that rotates and is brought into contact with a continuously running support, and the rubbing cloth is used as a support. In the rubbing apparatus for rubbing the alignment film forming layer formed on the surface, a humidifying means for humidifying the front chamber before the rubbing, and a dehumidifying means for dehumidifying the rubbing chamber for rubbing, By adjusting the relative humidity in the rubbing chamber by the dehumidifying means and changing the rigidity of the pile yarn, the degree of bending during rubbing of the pile yarn is determined by the total length A of the pile yarn before rubbing, and the pile When expressed as a ratio (B / A) × 100 of the length B from the base fabric surface to the alignment film forming layer surface in the rubbing in which a rubbing load is applied to the yarn, the ratio is Providing a rubbing apparatus characterized by setting the range of 0% to 90%.

  The ninth aspect constitutes the present invention as an apparatus.

  In the rubbing apparatus of the present invention, a partition structure is provided between the front chamber and the rubbing chamber to partition the front chamber and the rubbing chamber while leaving only a narrow gap through which the support can pass. Is preferred.

  In the rubbing apparatus of the present invention, a first atmospheric pressure adjusting means for adjusting the atmospheric pressure in the front chamber, a second atmospheric pressure adjusting means for adjusting the atmospheric pressure in the rubbing chamber, and the first and second atmospheric pressure adjusting means. And a control means for controlling the pressure difference.

  This makes it difficult for moisture from the front chamber, which applies moisture to the support, to be brought into the rubbing chamber, and makes it easier to control the rubbing chamber with appropriate humidity with high accuracy, thus suppressing dust generation during rubbing more effectively. can do. In this case, it is better if the partition structure and the atmospheric pressure control are used in combination.

  In the rubbing treatment apparatus of the present invention, it is preferable that the rubbing chamber is provided with a rubbing cloth material dehumidifying means for directly dehumidifying the rubbing cloth material of the rubbing roller.

  As described above, by providing the rubbing cloth material dehumidifying means in addition to the dehumidifying means of the rubbing chamber, the moisture of the rubbing cloth material can be directly controlled, so that dust generation during rubbing can be more effectively suppressed. .

  According to a thirteenth aspect of the present invention, in order to achieve the above object, an alignment film is formed on a support by the rubbing method according to any one of the first to eighth aspects. I will provide a.

  According to a thirteenth aspect of the present invention, an alignment film is manufactured by applying the rubbing method of the present invention.

  According to a fourteenth aspect of the present invention, in order to achieve the object, a liquid crystal layer forming step of forming a liquid crystal layer on the alignment film formed by the manufacturing method according to the thirteenth aspect, and aligning the formed liquid crystal layer And a liquid crystal layer fixing step for fixing the aligned liquid crystal layer. A method for manufacturing an optical member is provided.

  Claim 14 applies the rubbing method of the present invention to the manufacturing method of the optical member, and the optical member manufactured thereby, for example, an optical compensation film used for a liquid crystal display device, a brightness enhancement film, and the like. Bright spot defects can be significantly reduced.

  According to the present invention, it is possible to simultaneously solve both the bright spot defect caused by orientation failure and the bright spot defect caused by dust.

Explanatory drawing which shows the production line of the optical compensation film to which the rubbing method and apparatus of this invention are applied Explanatory drawing explaining the rubbing chamber provided with the front chamber provided with the humidification means before rubbing, and the dehumidification means at the time of rubbing The partial expansion perspective view which shows the structure of the cloth material for rubbing Explanatory drawing explaining the bending degree of pile yarn Graph showing the relationship between the degree of pile yarn deflection and the relative humidity of the rubbing chamber Illustration of pile yarn with filament coated resin Explanatory drawing explaining the preferable structure for the moisture adjustment of the cloth material for rubbing Example table Graph showing the relationship between the degree of pile yarn deflection and the number of bright spots on the optical compensation film Graph showing the relationship between the degree of pile yarn deflection and the amount of dust generated during rubbing Table showing the relationship between the degree of pile yarn deflection and the angle of inclination

  Hereinafter, preferred embodiments of the rubbing method and apparatus, the alignment film and the optical member manufacturing method of the present invention will be described in detail.

  FIG. 1 shows an optical compensation film manufacturing line as an example of an optical member manufacturing line to which the rubbing method and apparatus of the present invention are applied. In this embodiment, an example of manufacturing an optical compensation film will be described. However, the present invention is an optical member including a step of forming an alignment film by performing a rubbing process in a manufacturing line, such as a brightness enhancement film. Can be provided to all.

[Formation process of alignment film forming layer]
As shown in FIG. 1, a belt-like flexible support (hereinafter referred to as a web) 16 that is a transparent support is sent out from a delivery machine 66. The web 16 is guided by a guide roller 68 and passes through a dust remover 15A to remove dust attached to the surface of the web 16. As the dust remover 15A, various known types can be adopted. For example, a configuration in which compressed air (nitrogen gas) subjected to electrostatic dust removal is sprayed onto the surface of the web 16 to remove dust adhering to the surface of the web 16 can be suitably employed.

  A bar coating device 11A is provided downstream of the dust remover 15A in the web running direction (hereinafter, simply referred to as downstream), and a coating solution containing alignment film forming resin is applied to the web 16. The coating device is not limited to a bar coating device, but various coating devices such as a gravure coater, roll coater (transfer roll coater, reverse roll coater, etc.), die coater, extrusion coater, fountain coater, curtain coater, dip coater, spray coater. Or a slide hopper etc. are employable.

  A drying zone 76A and a heating zone 78A are sequentially provided downstream of the bar coating device 11A, and an alignment film forming layer is formed on the web 16 by drying and heating.

[Rubbing step of alignment film forming layer]
After applying and drying the coating liquid containing the alignment film forming resin, the web 16 is guided by the guide roller 68 and sent to the front chamber 20 before being rubbed. As shown in FIG. 2, the front chamber 20 is formed in a tunnel shape in which an inlet 20A and an outlet 20B of the web are opened. Further, the front chamber 20 is provided with humidifying means 21 for humidifying the web 16 before rubbing. In the humidifying means 21, the humidified air is adjusted by the humidifying moisture adjusting device 21A, and the humidified air is supplied into the front chamber 20 via the humidifying duct 21B. Moreover, the air in the front chamber 20 circulates to the humidified moisture adjusting device 21A via the exhaust duct 21C. Thereby, the inside of the front chamber 20 is adjusted to be 55% or more and 80% or less in relative humidity.

  As described above, the humidifying means 21 is provided in the front chamber 20 before rubbing, and the web 16 is humidified by setting the relative humidity in the front chamber 20 to 55% or more and 80% or less. Since the surface defects can be eliminated by eliminating the traces of stretching, bright spot defects due to poor alignment can be suppressed.

  The web 16 humidified in the front chamber 20 is sent to the rubbing chamber 22. As shown in FIG. 2, the rubbing chamber 22 has a web inlet 22 </ b> A and an outlet 22 </ b> B, and a rubbing device 70 is provided in the rubbing chamber 22.

  The rubbing roller 72 is provided for rubbing the alignment film forming layer. A dust remover 71 is provided upstream of the rubbing roller 72 to remove dust adhering to the surface of the web 16.

  The rubbing device 70 can rotationally drive a rubbing roller 72 in which a rubbing cloth material 1 to be described later is wound around the outer peripheral surface, and can control the rotational speed to about 1000 rpm, for example. The shape of the rubbing roller 72 is, for example, an outer diameter of 150 mm, and the length can be a roller shape slightly longer than the width of the web 16 even when the rubbing angle (winding angle) is applied. The rubbing device 70 is rotatable in a horizontal plane with respect to the traveling direction of the web 16 so that the rubbing device 70 can be adjusted to an arbitrary rubbing angle.

  A roller stage 84 is provided above the rubbing roller 72, and backup rollers 86 and 88 are rotatably attached to the lower surface of the roller stage 84 via springs. The backup rollers 86 and 88 are provided with a mechanism for detecting the tension of the web 16 so that tension management during rubbing can be performed.

  Further, the backup rollers 86 and 88 can be adjusted up and down, and the wrap angle of the web 16 to the rubbing roller 72 can be adjusted by moving the rollers up and down.

  With the above configuration, the alignment film forming layer on the surface (lower surface) of the web 16 is pressed by the rubbing roller 72 pressed from the lower side while the web 16 is pressed from above by the backup rollers 86 and 88 and the rubbing load is applied. The surface is rubbed to form an alignment film imparted with alignment. A dust remover 15 </ b> B is provided downstream of the rubbing device 70, and dust attached to the surface of the web 16 can be removed.

  As shown in FIG. 3, the rubbing cloth material 1 is formed by weaving pile yarns 4 into a base fabric 5 in which warp yarns 2 of the ground fabric structure and weft yarns 3 of the ground fabric texture are woven in a lattice shape. . Among these, a material in which pile yarns 4 are woven into three wefts 3 like a rubbing fabric material 1 shown in FIG. 3A is called a W structure, and a rubbing fabric material 1 shown in FIG. 3B. As described above, the pile yarn 4 woven into one weft 3 is referred to as a V structure. The W structure and the V structure differ only in how the pile yarns 7 are woven, and the same materials can be used.

  Examples of the base fabric 5 include polyamides such as nylon 6-6 (registered trademark), polyesters such as polyethylene terephthalate, polyolefins such as polyethylene, polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, polyacrylonitrile, Synthetic fibers such as acrylics such as acrylamide and methacrylamide, poly (vinylidene cyanide), polyfluoroethylene and polyurethane, natural fibers such as silk, cotton, wool, cellulose and cellulose ester, and regenerated fibers (rayon, acetate, etc.) The fiber which combined 1 type (s) or 2 or more types chosen from among these is mentioned.

  The warp yarn 2 and the weft yarn 3 of the base fabric 5 are preferably used in a state where, for example, 70 pieces of 1.4 denier fibers are combined to form a filament of about 100 denier (long continuous fiber). As such warp yarns 2 and weft yarns 3, for example, cupra rayon (Bemberg) filaments manufactured by Asahi Kasei Corporation can be preferably used.

  Further, as shown in FIG. 2, the rubbing chamber 22 is provided with a dehumidifying means 23 for reducing the relative humidity in the rubbing chamber 22. The dehumidifying means 23 sucks the air in the rubbing chamber 22 into the dehumidifying moisture adjusting device 23A via the suction duct 23B, dehumidifies the air with the dehumidifying moisture adjusting device 23A, and then the inside of the rubbing chamber 22 via the air supply duct 23C. Return to. Thereby, the degree of flexure of the pile yarn 4 during rubbing is appropriately set by adjusting the relative humidity in the rubbing chamber 22 where rubbing is performed to change the rigidity of the pile yarn 4.

  That is, the ratio (B / A) of the total length A of the pile yarn before rubbing and the length B from the surface of the base fabric 5 in the rubbing to which the rubbing load is applied to the pile yarn to the alignment film forming layer surface × When represented by 100, the degree of deflection of the pile yarn 4 is set so that the ratio is in the range of 60 to 90%.

  The appropriate degree of bending of the pile yarn will be described in more detail. As shown in FIG. 4, the entire length A of the pile yarn 4 before rubbing (FIG. 4A) and the rubbing load are applied to the pile yarn 4. When expressed as a ratio (B / A) × 100 with a length B (FIGS. 4B, 4C, and 4D) from the surface of the base fabric 5 to the surface of the alignment film forming layer 19 during rubbing. The ratio is set in the range of 60 to 90%. Thereby, it is possible to simultaneously solve both the bright spot defect caused by the orientation failure and the bright spot defect caused by the dust.

  FIG. 4 (b) shows that the ratio of the length B1 to the total length A of the pile yarn 4 exceeds 90% and the degree of deflection of the pile yarn 4 is too small, so that dust generation during rubbing is small, but orientation due to insufficient rubbing. This is a case where a defect occurs. Reference numeral 25 denotes dust generated by dust generation.

  FIG. 4 (c) shows that the ratio of the length B2 to the total length A of the pile yarn 4 satisfies the range of 60 to 90%, the degree of bending of the pile yarn 4 is appropriate, dust generation during rubbing is small, and rubbing This is a case where poor alignment does not occur because of sufficient performance.

  FIG. 4 (d) shows that the ratio of the length B3 to the total length A of the pile yarn 4 is less than 60%, and the degree of bending of the pile yarn 4 is too large, so that the rubbing performance is sufficient and no orientation failure occurs. This is the case when the amount of dust generation increases.

  Here, the relationship between the relative humidity in the rubbing chamber 22 and the degree of bending of the pile yarn 4 will be described.

  As shown in FIG. 5, as the relative humidity in the rubbing chamber 22 increases, the degree of bending of the pile yarn 4 (length B with respect to the total length A) tends to decrease, and the pile yarn 4 has a relative humidity of 10 to 50%. Satisfies the range of 60-90%. The relationship between the relative humidity of the rubbing chamber 22 and the degree of bending of the pile yarn 4 is somewhat different in the hygroscopicity depending on the type of fiber used for the rubbing cloth material 1. It is better to test in advance the relative humidity of the rubbing chamber 22 that satisfies the range of 90%.

  The reason for setting the lower limit of the relative humidity in the rubbing chamber 22 to 10% is that if the rubbing chamber 22 is kept extremely dry to 10% or less, the alignment film forming layer is adversely affected.

  If the relative humidity of 10 to 50% can be maintained without dehumidifying the inside of the rubbing chamber 22 with the dehumidifying means 23, it is not necessary to operate the dehumidifying means 23, but the relative humidity in the front chamber 20 is 55% to 80%. When the web 16 humidified below is conveyed to the rubbing chamber 22 as it is, the relative humidity in the rubbing chamber 22 usually increases to exceed 50%. Thereby, the water | moisture content of the cloth material 1 for rubbing wound around the rubbing roller 72A (72B) rises, and since the degree of bending at the time of rubbing the pile yarn 4 increases, dust generation increases. Furthermore, if the alignment film forming layer 19 that has been humidified in the front chamber 20 is rubbed, the alignment film forming layer 19 is easily damaged.

  In order to appropriately adjust the moisture of the rubbing cloth material 1, it is preferable to add the configuration described in FIG. 7 in addition to the dehumidification of the rubbing chamber 22.

  As shown in FIG. 7, the front chamber 20 and the rubbing chamber 22 are connected by a tunnel-shaped communication path 31, and the communication path 31 leaves only a narrow gap through which the web 16 can pass and the front chamber 20. A pair of rollers 33, 33 that partition the rubbing chamber 22 is provided. Thereby, it is possible to prevent moisture in the front chamber 20 from being brought into the rubbing chamber 22.

  As shown in FIG. 7, a pair of plate-like members 35 and 35 may be used as members for partitioning the front chamber 20 and the rubbing chamber 22, but the roller 33 rotates even when the web 16 comes into contact with it. 16 is hardly scratched.

  In addition, clean air is supplied to the front chamber 20 and the rubbing chamber 22 via the air conditioning duct 37, and an air conditioning duct 37 </ b> A that extends to the front chamber 20 and an air conditioning duct that extends to the rubbing chamber 22. 37B is provided with adjustment valves 39A and 39B for adjusting the air supply amount.

  On the other hand, in the front chamber 20 and the rubbing chamber 22, pressure sensors 41 </ b> A and 41 </ b> B that measure the atmospheric pressure (indoor pressure) of the chambers 20 and 22 are provided.

  The pressure data measured by the pressure sensors 41A and 41B is input to the pressure controller 43, and the pressure controller 43 supplies air to the rubbing chamber 22 rather than the front chamber 20 based on the input pressure data. Is controlled so that the opening degree of each of the adjustment valves 39A and 39B is increased. Thereby, since the atmospheric pressure in the rubbing chamber 22 becomes higher than the atmospheric pressure in the front chamber 20, it is possible to prevent moisture in the front chamber 20 from being brought into the rubbing chamber 22.

  It is more preferable to use both the structure for partitioning the front chamber 20 and the rubbing chamber 22 and the atmospheric pressure control of the front chamber 20 and the rubbing chamber 22 together.

  Furthermore, as shown in FIG. 7, it is better to provide an air nozzle 45 for blowing dry air to the rubbing cloth material 1 wound around the rubbing roller 72. Thereby, the water | moisture content of the cloth material 1 for rubbing can be adjusted directly. In this case, it is preferable to provide the air nozzle 45 at a downstream position of the dust remover 71 when viewed from the rotation direction of the rubbing roller 72. Thereby, after the rubbing waste adhering to the rubbing cloth material 1 is removed by the dust remover 71, dry air is blown onto the rubbing cloth material 1, so that the rubbing waste is not scattered in the rubbing chamber 22.

[Liquid crystal layer forming step]
As shown in FIG. 1, a bar coating device 11 </ b> B is provided downstream of the dust remover 15 </ b> B, and a coating liquid containing disconematic liquid crystal is applied to the web 16. As the coating device 11B, various coating devices can be used in the same manner as when the coating liquid containing the alignment film forming resin is applied to the web 16.

  A drying zone 76B and a heating zone 78B are sequentially provided downstream of the bar coating device 11B, and a liquid crystal layer is formed on the web 16. Further, an ultraviolet lamp 80 is provided downstream of this, and the liquid crystal is cross-linked by ultraviolet irradiation to form a desired polymer. Then, the protective film 88A, which is inspected by the inspection device 84 and delivered from the laminating machine 88, is laminated on the web 16, and the web 16 on which the polymer is formed is taken up by the winder 82 provided downstream thereof. Thereby, an optical compensation film is manufactured.

  In the present embodiment, the entire optical compensation film production line 10, particularly the bar coating apparatuses 11 </ b> A and 11 </ b> B, may be installed in a clean atmosphere such as a clean room. At that time, the cleanliness is preferably class 1000 or less, more preferably class 100 or less, and still more preferably class 10 or less.

  In the above embodiment, the degree of bending of the pile yarn 4 during rubbing is set by adjusting the relative humidity in the rubbing chamber 22. However, as shown in FIG. 6, the surface of the filament 6 (long continuous fiber) constituting the pile yarn 4 is coated with a resin to form a coating layer 7, thereby changing the rigidity of the pile yarn 4. You may set the bending degree of the thread | yarn 4 in the range of 60 to 90% of the said ratio. The rigidity of the pile yarn 4 can be arbitrarily set by selecting a resin material (soft resin, hard resin) to be coated on the filament 6 and changing the thickness of the resin layer to be coated.

  As the filament 6, for example, recycled fibers (rayon, polynosic, cupra), semi-synthetic fibers (acetate, triacetate, promix), and synthetic fibers (polyester, nylon, acrylic, vinylon, polyurethane) can be preferably used.

  Examples of the present invention will be described below with examples of optical compensation films, but the present invention is not limited to these examples.

[Example A]
Example A is a test in which the relationship between the degree of deflection of the pile yarn 4 (the ratio of the length B to the total length A) and the number of detected bright spots (pieces / m) of the optical compensation film was examined.

(Manufacture of optical compensation film)
A long-chain alkyl-modified poval (MP-203, A 5% by weight solution (manufactured by Kuraray Co., Ltd.) was applied, dried at 90 ° C. for 4 minutes, and then rubbed to form an alignment film forming layer having a thickness of 2.0 μm. The conveyance speed of the web 16 was 20 m / min.

  Next, the web 16 on which the alignment film forming layer 19 was formed was sent to the front chamber 20 that was humidified and adjusted to a relative humidity of 70% to humidify the web 16 and then sent to the rubbing chamber 22. Then, in the rubbing apparatus 70, the surface of the alignment film forming layer 19 was rubbed while continuously transporting the web 16 at 20 m / min. The rubbing was performed at a rotational speed of the rubbing roller 72 of 300 rpm.

  When rubbing in the rubbing chamber 22, the relative humidity in the rubbing chamber 22 is adjusted so that the degree of deflection of the pile yarn 4 of the rubbing cloth material 1 is in the range of 58% to 100%, and tests 1 to 7 are performed. did. The inclination angle of the pile yarn 4 is 15 degrees and is common.

  Test 1 is a case where the relative humidity of the rubbing chamber 22 is adjusted so that the degree of bending of the pile yarn 4 is 58%.

  Test 2 is a case where the relative humidity of the rubbing chamber 22 is adjusted so that the degree of deflection of the pile yarn 4 is 60%.

  Test 3 is a case where the relative humidity of the rubbing chamber 22 is adjusted so that the degree of deflection of the pile yarn 4 is 68%.

  Test 4 is a case where the relative humidity of the rubbing chamber 22 is adjusted so that the degree of bending of the pile yarn 4 is 78%.

  Test 5 is a case where the relative humidity of the rubbing chamber 22 is adjusted so that the degree of bending of the pile yarn 4 is 90%.

  Test 6 is a case where the relative humidity of the rubbing chamber 22 is adjusted so that the degree of deflection of the pile yarn 4 is 92%.

  Test 7 is a case where the relative humidity of the rubbing chamber 22 is adjusted so that the degree of deflection of the pile yarn 4 is 100%.

Then, after the rubbing performed under the rubbing conditions of Tests 1 to 7, the web 16 having the obtained alignment film was continuously conveyed at 20 m / min while the discotic compound TE-8 was formed on the alignment film. A mixture obtained by adding 1% by weight of a photopolymerization initiator (Irgacure 907, manufactured by Nippon Ciba Geigy Co., Ltd.) to a mixture of (3) and TE-8 (5) in a weight ratio of 4: 1. A 10 wt% methyl ethyl ketone solution (coating solution) was applied at a coating amount of 5 ml / m ² using the bar coating device 11B, and then passed through the drying zone 76B and the heating zone 78B.

  Air of 0.1 m / second was sent to the drying zone 76B, and the heating zone 78B was adjusted to 130 ° C. The web 16 entered the drying zone 76B 3 seconds after coating, and entered the heating zone 78B after another 3 seconds. The web 16 passed through the heating zone 78B in about 3 minutes.

  Next, the surface of the liquid crystal layer was irradiated with ultraviolet rays by an ultraviolet lamp 80 while the web 16 coated with the alignment film and the liquid crystal layer was continuously conveyed at 20 m / min. That is, the web 16 that passed through the heating zone 78B was irradiated with ultraviolet rays having an illuminance of 600 mW for 4 seconds by an ultraviolet lamp 80 (output: 160 W / cm, emission length: 1.6 m) to crosslink the liquid crystal layer.

  Further, the optical properties of the surface of the web 16 on which the alignment film and the liquid crystal layer are formed are measured and inspected by the inspection device 84, and then the protective film 88A is laminated on the surface of the liquid crystal layer by the laminating machine 88, and the winder 82 to obtain an optical compensation film.

≪Detection of number of bright spots≫
And the number of bright spots was investigated about the optical compensation film manufactured by each of the tests 1-7. In the inspection apparatus for the number of bright spots, a CCD camera is arranged on the alignment film forming layer side of the web 16, and a light source is arranged at a position facing the CCD camera with the web 16 in between. The inspection is performed with a film sandwiched between crossed Nicols polarizing plates, light is applied from a light source, and the light transmission state is continuously monitored by a CCD camera. To do. Further, the size of bright spots was classified by S printing (50 to 70 μm) and M printing (70 to 100 μm), and the number of bright spots of S printing and M printing was examined.

≪Measurement of dust generation≫
In addition, a dust generation measuring device (LIGHTHOUSE: Handheld3016 type) is installed in the exhaust pipe (not shown) removed by the dust remover 71 located in the rubbing chamber 22 to measure the amount of dust generated during rubbing. did. As the dust generation amount, the number of dusts of 0.3 μm or more detected at a measurement time per minute was measured. The measurement was carried out for 1 minute, 10 times repeatedly with a 5 second stop, and the average value was shown.

≪Test results≫
The test results are as shown in the table of FIG. 8. FIG. 9 is a graph of the number of bright spots in the table of FIG. 8, and FIG. 10 is a graph of the dust generation state during rubbing.

  From these figures, in Test 1 in which the degree of deflection during rubbing of the pile yarn 4 is less than 60%, the number of bright spots for both M printing and S printing increases rapidly. That is, when the degree of deflection is less than 60%, the contact area of the pile yarn 4 with the alignment film forming layer is increased, so that the alignment performance is improved, but dust generation during rubbing increases rapidly. Therefore, it can be seen that when the optical compensation film is manufactured, since the bright spot defects due to dust increase even if the bright spot defects due to poor alignment can be suppressed, the total bright spot defects increase.

  On the other hand, in Tests 6 and 7 in which the degree of bending of the pile yarn exceeded 90%, the number of bright spots for both M printing and S printing rapidly increased. That is, when the degree of deflection exceeds 90%, the contact area of the pile yarn 4 with respect to the alignment film forming layer becomes small, so that dust generation is suppressed but orientation failure occurs. Therefore, it can be seen that when the optical compensation film is manufactured, since the bright spot defects due to the orientation failure increase even if the bright spot defects caused by dust can be suppressed, the bright spot defects increase in total.

  On the other hand, the tests 2 to 5 in which the degree of bending of the pile yarn is in the range of 60 to 90% can reduce both the number of bright spots for M printing and S printing. It is considered that this is because, when the degree of bending of the pile yarn is set in the range of 60 to 90% and rubbed, sufficient orientation performance can be ensured while suppressing dusting and causing no orientation failure.

  From the above, by setting the degree of bending of the pile yarn in the range of 60 to 90% and rubbing, it is possible to simultaneously solve both the bright spot defect caused by orientation failure and the bright spot defect caused by dust. it can.

[Example B]
In Example B, in order to simultaneously solve both the bright spot defect caused by the orientation failure and the bright spot defect caused by the dust, the inclination angle (26 to 40 °) of the pile yarn 4 is used as in Patent Document 5. It is not an essential solution but a test for demonstrating that there is an essential solution to the degree of deflection of the pile yarn 4 as in the present invention.

  The test method and measurement method are the same as in Example A.

≪Test results≫
The test results are as shown in the table of FIG.

  In Test 4, the result of Example A was placed as it was, and the rubbing process was performed at an inclination angle of 15 °.

  In test 8, the pile yarn 4 was rubbed by setting the inclination angle of the pile yarn 4 to be 5 ° smaller than that of the test 4 while maintaining the deflection degree of the pile yarn 4 at 78% satisfying the conditions of the present invention.

  Test 9 is such that the inclination angle of the pile yarn 4 is 35 ° larger than Test 4 (satisfying the range of Patent Document 5) while maintaining the degree of deflection of the pile yarn 4 at 78% that satisfies the conditions of the present invention. The rubbing process was set to

  In Test 10, the inclination angle of the pile yarn 4 is 40 ° (satisfying the range of Patent Document 5) larger than that of the Test 9 while maintaining the bending degree of the pile yarn 4 at 78% that satisfies the conditions of the present invention. The rubbing process was performed with the setting as described above.

  In Test 11, the rubbing treatment was performed by setting the degree of deflection of the pile yarn 4 to 58% not satisfying the lower limit of the present invention while maintaining the inclination angle of the pile yarn 4 at 35 °.

In the test 12, the rubbing treatment was performed by setting the degree of deflection of the pile yarn 4 to 92% not satisfying the upper limit of the present invention while maintaining the inclination angle of the pile yarn 4 at 35 °. As can be seen from the results, Tests 4, 8, 9, and 10 satisfying the degree of bending of the pile yarn of the present invention have both the number of bright spots and the amount of dust generated even when the inclination angle of the pile yarn is changed in the range of 5 to 40 °. A good result was obtained.

  In contrast, even in the case of 35 ° that satisfies the inclination angle (26 to 40 °) of the pile yarn of Patent Document 5 as in Tests 11 and 12, the degree of bending of the pile yarn is 60 to 60 of the present invention. If the range of 90% is not satisfied, it can be seen that either the number of bright spots or the amount of dust generation deteriorates.

  DESCRIPTION OF SYMBOLS 1 ... Cloth for rubbing, 2 ... Warp, 3 ... Weft, 4 ... Pile yarn, 5 ... Base fabric, 6 ... Filament, 7 ... Coating layer, 10 ... Production line of optical compensation film, 11 ... Bar coating device, 16 DESCRIPTION OF SYMBOLS ... Web, 20 ... Front chamber, 21 ... Humidification means, 22 ... Rubbing chamber, 23 ... Dehumidification means, 66 ... Delivery machine, 68 ... Guide roller, 70 rubbing apparatus, 72 ... Rubbing roller, 76 ... Drying zone, 78 ... Heating Zone, 80 ... UV lamp, 82 ... winder, 84 ... roller stage, 86, 88 ... backup roller

Claims (15)

An alignment film is formed by rubbing the alignment film forming layer formed on the support with the rubbing cloth material by bringing the continuous running support into contact with a rubbing roller that is rotated while the rubbing cloth is wound. In the rubbing method to
The rubbing cloth material is formed by weaving pile yarn into a base fabric composed of warp and weft of a ground fabric structure,
By changing the stiffness of the pile yarn, the degree of deflection during rubbing of the pile yarn is determined by the total length A of the pile yarn before rubbing, and the rubbing during the rubbing in which a rubbing load is applied to the pile yarn. When expressed as a ratio (B / A) × 100 to the length B from the base fabric surface to the alignment film forming layer surface, the rubbing is performed in a state where the ratio is set in a range of 60 to 90%. How to rub.   The rubbing method according to claim 1, wherein the degree of bending of the pile yarn is set within the ratio range by adjusting the relative humidity in the rubbing chamber in which the rubbing is performed to change the stiffness of the pile yarn.   The rubbing method according to claim 2, wherein the relative humidity in the rubbing chamber is adjusted to a range of 10 to 50%. Rubbing method according to claim 1, characterized in that setting the deflection degree of the pile yarns within the ratio range by varying the stiffness of the pile yarn by coating a resin on the surface of the pile yarn. A humidifying step of applying moisture to said support, a wet pre-chamber before the rubbing,
The rubbing chamber to be rubbed is dehumidified to be lower than the relative humidity in the front chamber, and moisture of the rubbing cloth rises due to moisture brought into the rubbing chamber from the front chamber by the transport of the support. The rubbing method according to any one of claims 1 to 4, further comprising a dehumidifying step for preventing water.   6. The rubbing according to claim 5, wherein humidification is performed so that the relative humidity of the front chamber is 55% or more and 80% or less, and dehumidification is performed so that the relative humidity of the rubbing chamber is 10 to 50%. Method.   Between the humidification step in the front chamber and the dehumidification step in the rubbing chamber, the front chamber and the rubbing chamber are partitioned by leaving only a narrow gap through which the support can pass, thereby The rubbing method according to claim 5, further comprising a moist feeling prevention step for preventing moisture from being brought into the rubbing chamber from a room.   The rubbing method according to any one of claims 5 to 7, further comprising a pressure control step of making the pressure in the rubbing chamber higher than the pressure in the front chamber. An alignment film is formed by rubbing the alignment film forming layer formed on the support with the rubbing cloth material by bringing the continuous running support into contact with a rubbing roller that is rotated while the rubbing cloth is wound. In the rubbing device to
Humidifying means for humidifying the front chamber before rubbing;
Dehumidifying means for dehumidifying the rubbing chamber for rubbing,
By adjusting the relative humidity in the rubbing chamber by the dehumidifying means and changing the rigidity of the pile yarn, the degree of bending of the pile yarn during rubbing is determined by the total length A of the pile yarn before rubbing, and the pile When expressed as a ratio (B / A) × 100 of the length B from the base fabric surface to the alignment film forming layer surface in the rubbing in which the rubbing load is applied to the yarn, the ratio is 60 to 90. A rubbing apparatus characterized by being set in a range of% .   The partition structure which partitions off the said front chamber and the said rubbing chamber is provided between the said front chamber and the said rubbing chamber, leaving only the narrow gap which the said support body can pass. The rubbing apparatus according to 1. First atmospheric pressure adjusting means for adjusting the atmospheric pressure in the front chamber;
Second atmospheric pressure adjusting means for adjusting the atmospheric pressure in the rubbing chamber;
The rubbing apparatus according to claim 9, further comprising a control unit that controls a pressure difference between the first and second pressure adjusting units.   The rubbing apparatus according to any one of claims 9 to 11, wherein the rubbing chamber is provided with a rubbing cloth material dehumidifying means for directly dehumidifying the rubbing cloth material of the rubbing roller.   An alignment film manufacturing method comprising forming an alignment film on a support by the rubbing method according to claim 1. A liquid crystal layer forming step of forming a liquid crystal layer on the alignment film formed by the manufacturing method according to claim 13;
A liquid crystal alignment step of aligning the formed liquid crystal layer;
And a liquid crystal layer fixing step for fixing the aligned liquid crystal layer.   The method of manufacturing an optical member according to claim 14, wherein the optical member is one of an optical compensation film and a brightness enhancement film used in a liquid crystal display device.

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