JP2012076853A - Film roll-up device and optical film manufacturing method using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable hard winding up by effectively eliminating an accompanied wind because the suction pressure can be raised lest the film be fluttered even in a method to eliminate the accompanied wind by a suction nozzle.SOLUTION: A wind-up device 10 that winds up a running film 12 on a wind-up shaft 18 to form a winding roll 28 is provided with a suction nozzle 32, which not only wounds to support the running film 12 at a predetermined or higher surface pressure but also sucks air from a triangular space part 36 at the predetermined or higher suction pressure, in the triangular space part 36 formed between the wound and supported film face and the winding roll 28 face making the wind-up starting point the summit. Here, the running film 12 is wound on and supported by a back-up roller 30 so that the surface pressure of the wound and supported film face becomes larger than the suction pressure of the suction nozzle 32 and the back-up roller 30 and suction nozzle 32 are integrally moved by a travel means 34 following the change of the winding diameter of the winding roll 28.

Description

  The present invention relates to a film winding apparatus and an optical film manufacturing method using the apparatus, and more particularly to a winding technique after a base film for an optical film is manufactured.

  For example, optical film such as a polarizing plate protective film of a liquid crystal display device and an optical compensation film and an antireflection film manufactured after passing through a treatment process such as coating and drying are required to have a high level of surface performance. The

  A base film such as triacetyl cellulose (TAC) is generally formed by a solution film forming method, and the formed base film is wound around a winding device. Therefore, winding failures such as winding misalignment, winding curl, scratches (including small scratches of about 50μ to 100μ), and film edge (commonly known as ears) deformation (knurling and stretching) during winding are in quality. It becomes a big problem.

  Since the winding failure in the base film leads to the subsequent coating failure and drying failure, the user is subjected to stricter inspection than the product film. In particular, due to the recent widening of the film (for example, 2000 mm or more), it has become difficult to wind up without causing a winding failure because air is easily trapped during winding.

  In general, when a film to be rolled is wound around a winding shaft to form a winding roll, the accompanying wind accompanying the traveling of the film and the accompanying wind accompanying the rotation of the winding roll are between the films. By being caught, the winding becomes loose and winding deviation occurs. Therefore, in order to obtain a winding hardness that does not cause winding deviation, it is necessary to exclude the accompanying wind during winding.

  A conventional general winding method that eliminates the accompanying wind is a method of increasing the winding tension. However, when the winding tension is increased, deformation of the ear portion (beveling or stretching of the knurling portion) occurs due to stress concentration on the ear portion in the film width direction. In particular, when the winding tension is increased in the case of a wide film in recent years, the elongation of the ear portion is increased.

  For this reason, a winding device that can eliminate the accompanying wind without increasing the winding tension has been developed.

  The winding device of Patent Document 1 is a method of sucking accompanying air by providing a suction nozzle in a triangular space between a film and a winding roll reaching a winding start point. In Patent Document 1, a low-friction resin lip is provided at the tip of the suction nozzle so that the degree of scratches generated even when the film is pulled by the suction pressure and flutters and contacts the suction nozzle and peripheral members is reduced. ing.

  The winding device of Patent Document 2 is a method of winding while winding the winding roll surface at the winding start point with a pressing roller, and sucking accompanying air by providing a suction nozzle in the triangular space described above. . This prevents the film from fluttering due to the suction pressure.

  The winding device of Patent Document 3 is a method of winding while not pressing with a wind pressure that blows out a winding start point from an air blowing nozzle instead of a pressing roller. This prevents the occurrence of winding failure such as scratches.

Japanese Patent Application Laid-Open No. 07-117901 Japanese Patent Laid-Open No. 06-156826 JP 2005-96915 A

  However, the conventional film winding device is insufficient as an optical film winding device that requires a high level of surface performance.

  That is, although the winding device of Patent Document 1 has a low-friction resin lip provided at the tip of the suction nozzle, if the suction pressure of the suction nozzle is increased, film fluttering increases, preventing the occurrence of scratches. I can't do it. If the suction pressure is lowered, the flutter of the film is reduced, but the desired winding hardness cannot be obtained. In recent years, as described above, the amount of the accompanying air has increased due to the widening of the optical film, and a suction pressure of 200 Pa or more is required. However, in the winding device of Patent Document 1, the suction pressure is set to 200 Pa or more. Then the fluttering will increase.

  Further, the winding device of Patent Document 2 can prevent the film from fluttering but cannot prevent the occurrence of scratches due to slip or the like because the pressing roller contacts the film surface. In the case of a wide film, the pressing roller needs to be a crown roller, but wrinkles are likely to occur.

  Moreover, since the winding device of patent document 3 can press a winding point by a completely non-contact method, generation | occurrence | production of a scratch like patent document 1 and 2 can be prevented, but a high wind pressure is required and fan equipment is required. Very expensive. In addition, there are problems such as scattering dust around the wind pressure and generating noise. In the case of an optical film, dust adhering to the film due to scattering or the like tends to cause a bright spot failure. Therefore, it is preferable to use a suction nozzle type winding device capable of sucking out dust.

  The present invention has been made in view of such circumstances, and even with a method in which the accompanying air is excluded by a suction nozzle, the suction pressure can be increased so that the film does not flutter. An object of the present invention is to provide a film winding apparatus that can be hard-rolled without being removed and is optimal for winding an optical film that requires a high level of surface performance, and a method for producing an optical film using the apparatus. To do.

  In order to achieve the above object, the film winding apparatus according to claim 1 is a film winding apparatus that forms a winding roll by winding a traveling film around a winding shaft, and is narrow with respect to the winding roll surface. The first film is arranged with a first gap, and the film to be wound is wound and supported at a predetermined surface pressure, and winding is started between the wound film surface and the winding roll surface. A backup roller that forms a triangular space portion having a point as a vertex, and a nozzle tip portion having a triangular cross section is disposed in the space portion, and the air in the space portion is sucked with a predetermined suction pressure or more. A suction nozzle in which two side surfaces forming a triangular shape are arranged with a second gap and a third gap narrow with respect to the backup roller surface and the winding roll surface, respectively, and winding of the winding roll To change in diameter Accordingly, a moving means for integrally moving the backup roller and the suction nozzle while maintaining the respective gaps, and the surface pressure of the film surface supported by the winding is greater than the suction pressure of the suction nozzle. The film is wound around and supported by the backup roller so as to be large.

  Note that the triangular space portion does not mean an accurate triangle, but a space having a substantially triangular shape.

  According to the configuration of the present invention, even if the air in the space is sucked by the suction nozzle, the film held on the backup roller with a surface pressure larger than the suction pressure does not flutter. Thereby, even if the backup roller and the suction nozzle are brought close to the winding roller surface to about 0.5 to 1 mm, the film does not come into contact with the suction nozzle to cause a scratch or the like. Thereby, the accompanying wind entering the space can be effectively removed with a high suction pressure.

  As a result, air can be effectively prevented from being caught between the film layers of the winding roll without increasing the winding tension during winding, so that the film can be wound hard. Furthermore, the dust removal effect which removes the dust etc. around the winding can be obtained with a high suction force.

  Since the film does not flutter by the suction of the suction nozzle as described above, the first gap between the backup roller and the winding roll, the second gap between the backup roller and the suction nozzle, and the first gap between the suction nozzle and the winding roll. 3 can be made to approach so as to be extremely small. The first to third gaps are preferably in the range of 0.5 to 10 mm, and more preferably in the range of 1 to 5 mm.

  As described above, even when the backup roller and the suction nozzle are arranged close to the winding roll with a narrow gap, the moving means follows up the change in the winding diameter of the winding roll and maintains each gap for backup. The roller and the suction nozzle are moved together. Thereby, even if the winding diameter of a winding roll increases, a backup roller and a suction nozzle do not contact a winding roll.

  Further, by increasing the wrap angle of the film that is wound around and supported by the backup roller, it is possible to reduce the film portion that is not wound around the backup roller and is floating in the air. Thereby, even if the space portion is sucked by the suction nozzle with a high suction pressure, there is no concern that the film comes into contact with the suction nozzle due to fluttering. Accordingly, it is possible to set conditions so that the tension, the backup roller diameter, and the film width are such that the surface pressure of the film supported by winding is 1500 Pa or more. In this case, it is necessary to suck the space with a suction pressure of at least 200 Pa.

  In addition, when a large wrap angle cannot be ensured due to reasons such as the film travel path, the surface pressure can be increased by using a tension roller that rotates and follows the film travel.

  Further, by reducing the roller diameter of the backup roller, the traveling direction of the straight traveling film can be changed abruptly, so the traveling vector of the accompanying wind accompanying the film changes from straight traveling to bending. Thereby, the amount of accompanying air flowing into the space can be reduced. A specific roller diameter of the backup roller is preferably in the range of 20 to 150 mm, and more preferably in the range of 20 to 50 mm.

  Further, according to the present invention, the suction nozzle itself can effectively block the accompanying air accompanying the film and the accompanying air accompanying the rotation of the winding roll from entering the space. In this case, it is preferable that the side surface on the backup roller side of the nozzle tip portion having a triangular cross section is formed on the same curvature surface as the curvature radius of the backup roller. Moreover, it is preferable that the side surface by the side of the winding roll of a nozzle front-end | tip part is formed in the same curvature surface as the curvature radius at the time of the maximum winding diameter of this winding roll.

  Moreover, it is preferable that the support frame that integrally supports the backup roller and the suction nozzle is formed with an opening through which the accompanying air accompanying the traveling of the film is released.

  In order to achieve the above object, a method for producing an optical film according to claim 9 of the present invention winds up a base film for producing an optical film with the film winding device according to any one of claims 1 to 8. It is characterized by comprising at least a step, a coating step of rewinding the wound-up base film to apply an optical coating solution, and a drying step of drying the applied coating layer.

  According to the present invention, since the winding process of the base film is performed by the winding device described above, winding deviation, winding wrinkles, scratches (including micro scratches of about 50 μ to 100 μ) at the time of winding, film edge No winding failure such as deformation (knurling or stretching) of the part (commonly known as an ear part) occurs. Thereby, since the coating failure resulting from a winding failure does not occur in the coating process and the drying process, a high-quality optical film can be manufactured.

  In this invention, it is preferable to provide the product film winding process which winds up the manufactured optical film with the film winding apparatus of any one of Claims 1-8. Even when the optical film of the product is wound, if the film winding apparatus of the present invention is used, a higher quality optical film can be produced.

  The optical film is preferably any one of a polarizing plate protective film, an optical compensation film, and an antireflection film for a liquid crystal display device. This is because such an optical film is required to have extremely high surface performance.

  According to the film winding device of the present invention, even when the accompanying air is excluded by the suction nozzle, the suction pressure can be increased so that the film does not flutter. It can be performed. This prevents winding failures such as winding misalignment, winding curl, scratches (including small scratches of about 50μ to 100μ), and film edge (commonly known as ears) deformation (knurling and stretching) during winding. it can.

  Therefore, according to the manufacturing method of the optical film using this film winding apparatus, the optical film which requires high planar performance can be manufactured.

Schematic diagram of incorporating the film winding device of the present invention into a base film production line Side view of the film winding device of the present invention The perspective view of the film winding apparatus of this invention Partial enlarged view of the film winding device of the present invention Schematic diagram of incorporating the film winding device of the present invention into an optical compensation film production line

  Hereinafter, a preferred embodiment of a film winding apparatus of the present invention and a method for producing an optical film using the apparatus will be described in detail.

  FIG. 1 is a conceptual diagram in which a film winding device 10 of the present invention (hereinafter referred to as “winding device”) is incorporated in a film forming line 14 for a base film 12. In the present embodiment, an example in which a film forming part 16 by a solution film forming method is provided as the film forming line 14 will be described.

  Although detailed steps by the solution casting method are not shown, the film forming unit 16 casts a dope obtained by dissolving, for example, triacetyl cellulose (TAC) with a solvent onto a support such as a traveling belt or a rotating drum. A cast film is formed. And it is an apparatus which manufactures a elongate film by drying a solvent, after peeling from a support body. The material of the base film 12 is not limited to TAC.

  As shown in FIG. 1, the winding device 10 is a device that winds the base film 12 formed by the film forming unit 16 around the winding shaft 18, and between the film forming unit 16 and the winding device 10. Are provided with a knurling device 20, an ear cutting device 22, and a winding tension control device 24 in this order from the winding device 10 side.

  The knurling device 20 forms a large number of minute convex portions by embossing or the like at the width direction end portion (commonly referred to as the ear portion 12a) of the base film 12 by a pair of knurling rollers including a mold roller 20A and a receiving roller 20B. Device. Examples of the minute convex shape include a truncated cone shape, a pyramid shape, a spherical shape, a waveform, a lattice shape, and an indefinite shape.

  The ear portion cutting device 22 is a device that cuts and removes the ear portion 12a of the base film 12 by a pair of knife-like (not shown) or rotary blade-like cutting blades 22A disposed at the end in the film width direction.

  The winding tension control device 24 mainly includes a pair of guide rollers 24A and 24B, a dancer roller 24C provided between the guide rollers 24A and 24B, and a tension measurement sensor 24D provided on one guide roller 24B. Composed. The tension signal measured by the tension measuring sensor 24D is sent to a controller (not shown) that controls the film forming line 14. The controller adjusts the winding tension to the set value by displacing the dancer roller 24C in the direction of the arrow 26 based on the tension signal from the tension measurement sensor 24D. For example, when the winding tension is higher than the set value, the dancer roller 24C is raised, and when the winding tension is lower than the set value, the dancer roller 24C is lowered. Thereby, the winding tension which winds up the base film 12 with the winding apparatus 10 is controlled within a fixed setting range. Accordingly, the winding roll 28 can be formed by winding the base film 12 with the optimum winding tension according to the winding length.

  In the present embodiment, the winding tension is reduced as the winding length increases and the winding diameter of the winding roll 28 increases. However, the present invention is not limited to this, and a known pattern can be used as appropriate.

  Next, the winding device 10 of the present invention will be described with reference to FIGS.

  As shown in these drawings, the winding device 10 mainly includes a backup roller 30, a suction nozzle 32, and a moving means 34.

  The backup roller 30 is disposed with a narrow first gap L1 (see FIG. 4) with respect to the surface of the winding roll 28, and supports the wound-up base film 12 with a surface pressure P1 of a predetermined level or more. At the same time, a triangular space 36 having a winding start point Q as an apex is formed between the surface of the base film 12 supported by winding and the surface of the winding roll 29.

  The suction nozzle 32 is provided with a nozzle tip 32A having a triangular cross section in the space 36, and sucks the air in the space 36 with a suction pressure P2 of a predetermined level or higher. The suction nozzle 32 has a hollow interior, and a slit-like suction port 32D (see FIG. 4) is formed in the nozzle tip portion 32A along the width direction of the winding roll 28. The suction nozzle 32 is connected to a vacuum device (not shown) via a suction pipe 32E. The suction nozzle 32 sucks the air in the space portion 36 so that the air is not caught between the film layers of the winding roll 28 during winding.

  In the suction of the space by the suction nozzle 32, the base film 12 is wound around the backup roller 30 so that the surface pressure P1 of the base film 12 wound and supported by the backup roller 30 is larger than the suction pressure P2 of the suction nozzle 32. It is supported by hanging.

  Further, as shown in FIG. 4, the two side surfaces 32B and 32C of the nozzle tip portion 32A forming a triangular cross section are narrower than the backup roller 30 surface and the winding roll 28 surface, respectively. It arrange | positions with the 3rd clearance gap L3. Thus, a wind-shielding structure is provided to block the accompanying wind accompanying the traveling of the base film 12 and the accompanying wind accompanying the rotation of the winding roll 28 from entering the space 36.

  The first to third gaps L1 to L3 are preferably in the range of 0.5 to 10 mm, and more preferably in the range of 1 to 5 mm. When the gaps L1 to L3 are less than 0.5 mm, the backup roller 30 may come into contact with the surface of the winding roll 28 via the base film 12 (normal thickness is about 80 μm). In addition, if it exceeds 10 mm, the wind shielding effect described later deteriorates, and the portion of the base film 12 that forms the space portion 36 that is not wrapped around and supported by the backup roller 30 (the portion that travels in the air) becomes long. This causes the base film 12 to flutter during suction by the suction nozzle 32. The first to third gaps L1 to L3 do not have to be the same gap, and may be different as long as they are within the above range. For example, the closer the backup roller 30 and the nozzle tip portion 32A are to the surface of the winding roll 28, the closer the distance between the backup roller 30 and the winding start point Q becomes, and the film length L4 existing in the air (FIG. 4). Reference) can be shortened, which is preferable. Specifically, L1 and L3 can be 0.5 to 1 mm.

  In this case, as shown in FIG. 4, the side surface 32 </ b> B on the backup roller 30 side of the nozzle tip portion 32 </ b> A having a triangular cross section is preferably formed on the same curvature surface as the curvature radius of the backup roller 30. Thereby, the accompanying wind W1 accompanying the traveling of the base film 12 can enter the space 36 more effectively.

  Further, since the entrainment air volume is larger when the winding diameter of the winding roll 28 is larger than when the winding diameter is small, the side surface 32C on the winding roll 28 side of the nozzle tip 32A is the maximum winding diameter of the winding roll 28. It is preferably formed on the same curvature surface as the radius of curvature at the time. Thereby, it is possible to more effectively shield the accompanying wind W2 accompanying the rotation of the winding roll 28 from entering the space 36.

  As shown in FIGS. 2 and 3, the moving means 34 follows the change in the winding diameter of the winding roll 28 and keeps the backup rollers 30 and the suction nozzles 32 while maintaining the aforementioned gaps L1, L2, and L3. Move together.

  The moving means 34 mainly supports both ends of the rotating shaft 30A of the backup roller 30 so as to be rotatable, and supports the suction nozzle 32 integrally with the backup roller 30, and the support frame 38 as indicated by an arrow A- in FIG. A feed screw mechanism 44 that reciprocates in the B direction, a winding diameter sensor 42 that measures the winding diameter of the winding roll 28 (see FIGS. 1 and 2), and the support frame 38 based on the measured value of the winding diameter sensor 42. And a control unit 46 (see FIG. 2) that controls the feed screw mechanism 44 so that the moving speed becomes the same as the winding diameter increasing speed.

  The winding diameter sensor 42 is not particularly limited as long as it can accurately measure changes in the winding diameter. For example, as shown in FIG. 1, a method of calculating a winding diameter from a pulse signal by attaching a pulse generator 42A as a winding diameter sensor 42 to the guide roller 24A may be adopted. Further, as shown in FIG. 2, the distance to the surface of the winding roll 28 may be measured using a laser range finder 42 </ b> B as the winding diameter sensor 42, and the winding diameter may be calculated from the measured distance.

  In the feed screw mechanism 44, a screw member 44A having a screw tip fixed to the central portion of the support frame 38, a servo motor 44B having a screw base end connected to rotate the screw member 44A, and the screw member 44A are screwed together. A nut member 44C, a support plate 44D that supports the nut member 44C on a winding device main body (not shown), and a pair of guide rods 44E and 44E that guide the movement of the support frame 38. The servo motor 44B is also fixed to a winder main body (not shown). As a result, when the servo motor 44B rotates the screw member 44A in the direction of the arrow X, for example, the backup roller 30 and the suction nozzle 32 integrally supported by the support frame 38 are guided by the guide rod 44E in the direction of the arrow A in FIG. Move to. When the servo motor 44B rotates the screw member 44A in, for example, the arrow Y direction, the backup roller 30 and the suction nozzle 32 integrally supported by the support frame 38 are guided in the arrow B direction in FIG. 2 while being guided by the guide rod 44E. Moving.

  According to the winding device 10 configured as described above, the backup roller 30 is provided with the narrow first gap L1 with respect to the surface of the winding roll 28, and the traveling base film 12 has a surface pressure higher than a predetermined level. Wrap and support at P1. The nozzle tip 32A is arranged in a triangular space 36 formed with the winding start point Q as the apex between the surface of the base film 12 supported by winding and the surface of the winding roll 28, and the space 36 air is sucked at a suction pressure P2 of a predetermined level or higher. In the suction by the suction nozzle 32, the surface pressure P1 of the base film 12 wound and supported on the backup roller 30 is wound and supported so as to be larger than the suction pressure P2 by the suction nozzle 32.

  Thus, even if the air in the space portion 36 is sucked by the suction nozzle 32, the base film 12 held by the backup roller 30 with the surface pressure P1 larger than the suction pressure P2 does not flutter (hereinafter referred to as “fluttering”). Prevention effect). Thereby, since the base film 12 does not come into contact with the suction nozzle 32 to generate a scratch or the like, the accompanying air entering the space 36 can be effectively removed with a high suction pressure P2. As a result, it is possible to effectively suppress air from being caught between the base film layers of the winding roll 28 without increasing the winding tension at the time of winding, so that the base film 12 can be wound tightly. Further, the dust removal effect of removing dust around the winding can be obtained by the high suction force P2.

  By the way, if the backup roller 30 is provided at a position away from the surface of the winding roll 28, the length of the base film 12 that travels in the air up to the winding start point Q becomes longer, so the surface of the base film 12 that travels in the air and the winding A triangular space 36 is formed between the surface of the roll 28 and the winding start point Q as an apex. As a result, when the space portion 36 is sucked by the suction nozzle 32 at a high suction pressure P2, the base film 12 supported in the air flutters and comes into contact with the suction nozzle 32 to generate scratches or the like.

  Specifically, in order to effectively suppress air from being sucked between the base film 12 layers of the winding roll 28 by sucking the air in the space portion 36 with the suction nozzle 32, the suction pressure of 200 Pa or more is used with the suction nozzle. It is preferable to suck the space 36 with P2. From this point of view, in the present invention, by increasing the wrap angle α (see FIG. 4) of the base film 12 wound and supported on the backup roller 30, the surface pressure P1 of the wound and supported base film 12 is 1500 Pa or more. Can be wrapped and supported.

  Note that the wrap angle α is a central angle from when the traveling base film 12 starts winding the backup roller 30 to when it ends.

  Therefore, even if the space portion 36 is sucked by the suction nozzle 32 with a suction pressure of 200 Pa or more, the base film 12 does not peel from the backup roller 30 and flutter as long as the pressure is up to 1500 pa. When a large wrap angle α cannot be ensured due to the path along which the base film 12 is conveyed, the same effect can be obtained by using a tension roller (not shown) that rotates and follows the traveling of the base film 12. An effect can be obtained.

  Further, by increasing the wrap angle α of the base film 12 with respect to the backup roller 30, the traveling direction of the base film 12 that travels straight can be rapidly changed. As a result, the traveling vector of the accompanying air W1 accompanying the base film 12 changes from straight to curved, so that the amount of the accompanying air flowing into the space 36 can be reduced (hereinafter referred to as “accompanied air vector variable effect”).

  In order for the traveling vector of the accompanying wind W1 to change from rectilinear to curved, it is preferable to reduce the roller diameter of the backup roller 30 to ensure a large wrap angle α. Specifically, the roller diameter of the backup roller 30 is preferably a small diameter in the range of 20 to 150 mm, and more preferably in the range of 20 to 50 mm. When the roller diameter is less than 20 mm, it becomes easy to bend.

  Furthermore, according to the present invention, the side surface 32B on the backup roller 30 side and the side surface 32C on the surface side of the winding roll 28 of the nozzle tip portion 32A formed in a triangular cross section have a narrow second and third gap L2. , L3. Thereby, the accompanying air W1 accompanying the base film 12 and the accompanying air W2 accompanying the rotation of the winding roll 28 can be effectively blocked by the suction nozzle 32 itself. Hereinafter, it is referred to as “wind shielding effect of the suction nozzle itself”).

  In this case, the side surface 32B on the backup roller 30 side of the nozzle tip portion 32A having a triangular cross section is preferably formed on the same curvature surface as the curvature radius of the backup roller 30. Thereby, the accompanying wind W1 accompanying the traveling of the base film 12 can be effectively shielded. Further, the side surface 32C on the winding roll 28 side of the nozzle tip portion 32A is preferably formed on the same curvature surface as the curvature radius at the time of the maximum winding diameter of the winding roll 28 (winding diameter at the end of winding). Thereby, the accompanying wind W2 by rotation of the winding roll 28 can be shielded effectively. That is, since the entrainment air volume is larger when the winding diameter of the winding roll 28 is larger than when the winding diameter is small, the side surface 32C on the winding roll 28 side of the nozzle tip portion 32A is set to the curvature radius at the maximum winding diameter. If it forms in the same curvature surface, the accompanying wind W2 can be shielded effectively. Further, since the radius of curvature at the maximum winding diameter is close to a straight line, the side surface 32C on the winding roll 28 side does not contact the surface of the winding roll 28 even when the winding diameter of the winding roll 28 is small. .

  In such winding, the moving means 34 moves the backup roller 30 and the suction nozzle 32 integrally while following the change in the winding diameter of the winding roll 28 while maintaining the gaps L1 to L3. 30 and the suction nozzle 32 do not contact the winding roll 28. In this case, as shown in FIGS. 2 and 3, it is preferable that an opening for releasing the accompanying air W <b> 1 is formed in the support sleeve that integrally supports the backup roller and the suction nozzle.

  Thus, even if the winding device 10 of the present invention is a system in which the accompanying air is excluded by the suction nozzle 32, the above-described fluttering prevention effect, the accompanying air vector variable effect, and the wind shielding effect of the suction nozzle 32 itself. Thus, hard winding can be performed while efficiently removing the accompanying wind without causing winding failure such as scratches. Therefore, it is optimal for winding an optical film that requires a high level of surface performance.

  Next, with reference to FIG. 5, an example of a manufacturing method for manufacturing an optical film by performing a process such as coating and drying on the base film 12 wound on the winding device 10 as described above will be described. An example of the optical compensation film will be described as an example of the optical film.

  In this embodiment, the case where the optical film is an optical compensation film will be described. However, the optical film is not limited to the optical compensation film, and is applied by heating air in a drying zone after applying a curable coating solution on a band-shaped base film. The present invention can also be applied to methods for producing various optical films, for example, an antiglare film and an antireflection film, for drying a layer and curing a coating layer dried in a curing zone.

  FIG. 5 is a schematic diagram showing a schematic configuration of an optical compensation film winding device 10 for carrying out the present invention.

  As shown in FIG. 5, the belt-like base film 12 on which the transparent resin layer for forming the alignment film is formed in advance is sent out from the delivery machine 112. The base film 12 is fed to a rubbing processing device 118 disposed on the downstream side while being guided by a guide roller 116, and the transparent resin layer is rubbed by the rubbing roller 120. Thereby, an alignment film is formed.

  In the rubbing processing device 118, the rubbing roller 120 is disposed between two transport rolls in the continuous transport process of the base film 12. And the base film 12 is continuously rubbed by being wrapped and conveyed by the rotating rubbing roller 120. In this case, the rubbing roller 120 may be arranged such that its rotation axis is inclined with respect to the transport direction of the base film 12.

  A dust remover 122 is disposed on the downstream side of the rubbing processing device 118 to remove dust adhering to the surface of the base film 12. Further, a gravure coating device 124 is disposed on the downstream side of the dust remover 122, and a coating liquid containing a liquid crystalline compound is applied on the alignment film of the base film 12. As the liquid crystal compound, a liquid crystal discotic compound having a crosslinkable functional group is preferably used.

The gravure coating device 124 includes a gravure roller 126 and a liquid receiving pan 128 disposed below the gravure roller 126 and filled with a coating liquid containing a liquid crystal compound. Is immersed in a coating solution. Further, a blade 129 is disposed at about 10 o'clock position of the gravure roller 126. As a result, the coating liquid is supplied to the cells on the surface of the gravure roller 126, and excess coating liquid is scraped off by the blade 129 and then applied to the alignment film surface of the base film 12. The coating amount of the coating solution is preferably 10 mL / m ² or less.

  The upstream guide roller 117 and the downstream guide roller 119 are arranged in a state substantially parallel to the gravure roller 126. Further, it is preferable that the upstream guide roller 117 and the downstream guide roller 119 are rotatably supported at both ends by a bearing member (such as a ball bearing) (not shown) and do not have a drive mechanism. The gravure coating device 124 is preferably provided in a clean atmosphere such as a clean room. The cleanliness is preferably class 1000 or less, more preferably class 100 or less, and still more preferably class 10 or less.

  As an example of the coating apparatus, FIG. 5 shows an example of the gravure coating apparatus 124, but the present invention is not limited to this. For example, methods such as a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a wire bar coating method, a micro gravure method, and an extrusion coating method can be used as appropriate. As for the conveyance speed of the base film 12, 5-200 m / min is preferable. Moreover, it is preferable that the width | variety of the coating layer formed in the base film 12 is 0.5-3 m.

  The base film 12 on which the coating layer containing the liquid crystal compound is formed is dried by an initial drying zone 130 provided immediately downstream. Further, a drying zone 132 is provided on the downstream side of the initial drying zone 130, and the dried coating layer of the base film 12 is further dried. A curing zone 136 is provided downstream of the drying zone 132, and the dried coating layer of the base film 12 is cured.

  In this case, it is preferable to provide an intermediate zone 134 that is controlled to be lower than either the temperature of the drying zone 132 or the temperature of the curing zone 136 between the drying zone 132 and the curing zone 136. When the coating layer is conveyed directly from the drying zone 132 to the curing zone 136 without the intermediate zone 134, the base film 12 heated in the drying zone 132 and the low molecular weight compound evaporated from the coating layer are more than in the drying zone 132. Condensation may occur in the low temperature curing zone 136. Deposits (condensate) deposited by condensation adhere to and contaminate the back surface of the base film 12 and the coating layer surface. In addition, dew condensation on the wall surface of the curing zone 136 drops and adheres to the back surface of the belt-like base film 12 and the coating film surface and is contaminated. Here, the low molecular weight compound means a compound having a molecular weight of 1000 or less.

  In the production of the optical compensation film, examples of the low molecular weight compound include triphenyl phosphate (TPP) and biphenyl diphenyl phosphate (BPP) as plasticizers, and Irgacure 184 and silane coupling as hardeners. Examples of the agent include acryloyloxypropyltrimethoxysilane.

  The optical compensation film 13 manufactured through the curing zone 136 is taken up by the take-up device 10 described above via the take-up tension control device 24 in the same manner as in the case of taking up the base film 12 described above. It is done.

  As described above, the winding device 10 of the present invention is used for both winding of the base film 12 and winding of the optical compensation film 13 manufactured by applying and drying the base film 12. With no winding failure such as winding misalignment, winding wrinkles, scratches (including micro scratches of about 50μ to 100μ), film edge (commonly known as ears) deformation (knurling or stretching), etc. An optical film having excellent planar performance can be manufactured.

  Next, various materials used for manufacturing the optical film of the present embodiment will be described.

  As the discotic compound (liquid crystal compound) used in the present embodiment, those described in JP-A-7-267902, JP-A-7-281028, and JP-A-7-306317 can be used. According to these, the optically anisotropic layer (coating layer containing a liquid crystalline compound) is a layer formed from a compound having a discotic structural unit. That is, the optically anisotropic layer is a polymer layer obtained by polymerization (curing) of a low molecular weight liquid crystal discotic compound layer such as a monomer or a polymerizable liquid crystal discotic compound.

  Examples of discotic (discotic) compounds include C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physicslett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), such as azacrown and phenylacetylene macrocycles.

  The above discotic (discotic) compounds generally have a structure in which these are used as a mother nucleus at the center of a molecule, and a linear alkyl group, an alkoxy group, a substituted benzoyloxy group, etc. are radially substituted as the linear chain. , Which shows liquid crystallinity and is generally called a discotic liquid crystal. However, the molecule itself is not limited to the above description as long as the molecule itself has negative uniaxiality and can give a certain orientation. In addition, in the above publication, it is not necessary for the final product to be formed from a discotic compound. For example, the low-molecular discotic liquid crystal has a group that reacts with heat, light, or the like. As a result, it may be polymerized or cross-linked by reaction with heat, light, etc., to have a high molecular weight and lose liquid crystallinity. Furthermore, it is preferable to use a compound containing at least one discotic compound capable of forming a discotic nematic phase or a uniaxial columnar phase and having optical anisotropy. The discotic compound is preferably a triphenylene derivative. Here, the triphenylene derivative is preferably a compound represented by (Chemical Formula 2) described in JP-A-7-306317.

  A cellulose acylate film such as TAC is preferably used as the base film 12 serving as a support for the alignment layer. Specifically, those described in detail in JP-A-9-152509 can be used. That is, the alignment film is provided on the cellulose acylate film or on an undercoat layer coated on the cellulose acylate film. The alignment film functions to define the alignment direction of the liquid crystalline discotic compound provided thereon. Here, the alignment film may be any layer as long as it can impart orientation to the optically anisotropic layer.

  Preferred examples of the alignment film include a layer subjected to a rubbing treatment of an organic compound (preferably a polymer), an oblique deposition layer of an inorganic compound, and a layer having a microgroove, and ω-tricosanoic acid, dioctadecylmethylammonium chloride and stearyl. Examples thereof include a cumulative film formed by Langmuir-Blodgett method (LB film) such as methyl acid, or a layer in which a dielectric is oriented by applying an electric field or a magnetic field.

  Examples of the organic compound for the alignment film include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleimide copolymer, polyvinyl alcohol, poly (N-methylolacrylamide), and styrene / vinyltoluene copolymer. , Polymers such as chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethyl cellulose, polyethylene, polypropylene and polycarbonate, and Examples of the compound include a silane coupling agent. Examples of preferable polymers include polyimide, polystyrene, polymers of styrene derivatives, gelatin, polyvinyl alcohol, and alkyl-modified polyvinyl alcohol having an alkyl group (preferably having 6 or more carbon atoms).

  Among them, alkyl-modified polyvinyl alcohol is particularly preferable and has an excellent ability to uniformly align a liquid crystal discotic compound. This is presumably because of the strong interaction between the alkyl chain on the alignment film surface and the alkyl side chain of the discotic liquid crystal. In addition, the alkyl group preferably has 6 to 14 carbon atoms, and is further bonded to polyvinyl alcohol via -S-,-(CH3) C (CN)-or-(C2H5) N-CS-S-. Preferably it is. The alkyl-modified polyvinyl alcohol has an alkyl group at the end, and preferably has a saponification degree of 80% or more and a polymerization degree of 200 or more. Moreover, the polyvinyl alcohol which has an alkyl group in the said side chain can utilize commercial items, such as Kuraray Co., Ltd. product MP103, MP203, R1130.

  A polyimide film (preferably a fluorine atom-containing polyimide) widely used as an alignment film of a liquid crystal display (LCD) is also preferable as the organic alignment film. This is done by applying polyamic acid (for example, LQ / LX series manufactured by Hitachi Chemical Co., Ltd., SE series manufactured by Nissan Chemical Co., Ltd.) to the web surface and baking at 100 to 300 ° C. for 0.5 to 1 hour. And then obtained by rubbing.

  Furthermore, alignment films applied to cellulose acylate films cure these polymers by introducing reactive groups into the polymers or using the polymers with crosslinkers such as isocyanate compounds and epoxy compounds. It is preferable that it is a cured film obtained by this.

  It is preferable that the polymer used for the alignment film and the liquid crystalline compound of the optically anisotropic layer are chemically bonded via the interface between these layers. The polymer of the alignment film is preferably formed from polyvinyl alcohol in which at least one hydroxyl group is substituted with a group having a vinyl part, an oxiranyl part or an aziridinyl part. A group having a vinyl moiety, an oxiranyl moiety or an aziridinyl moiety is preferably bonded to the polymer chain of the polyvinyl alcohol derivative via an ether bond, a urethane bond, an acetal bond or an ester bond. It is preferred that the group having a vinyl moiety, an oxiranyl moiety or an aziridinyl moiety does not have an aromatic ring. The polyvinyl alcohol is preferably (Chemical Formula 22) described in JP-A-9-152509.

  For the rubbing treatment, a treatment method widely used as a liquid crystal alignment treatment process of the LCD can be used. That is, a method of obtaining the orientation by rubbing the surface of the orientation film in a certain direction using paper, gauze, felt, rubber, nylon, polyester fiber or the like can be used. In general, it is carried out by rubbing several times using a cloth in which fibers having a uniform length and thickness are flocked on average.

  Moreover, as a vapor deposition material of the inorganic oblique vapor deposition film, SiO is representative, and metal oxides such as TiO 2 and ZnO 2, fluorides such as MgF 2, and metals such as Au and Al are exemplified. The metal oxide can be used as an oblique deposition material as long as it has a high dielectric constant, and is not limited to the above. The inorganic oblique deposition film can be formed using a deposition apparatus. An inorganic oblique vapor deposition film can be formed by performing vapor deposition with the web fixed or by moving the long web to perform continuous vapor deposition. Examples of a method for aligning an optical anisotropic layer without using an alignment film include a method of applying an electric field or a magnetic field while heating the optical anisotropic layer on the web to a temperature at which a discotic liquid crystal layer can be formed. .

  As an application method of an optical compensation film having an optically anisotropic layer formed on a cellulose acylate film to a liquid crystal display device, the optical compensation film is bonded to one side of a polarizing plate via an adhesive, or a polarizing element It is preferable that the optical compensation film is bonded to one side of the film with an adhesive as a protective film. The optically anisotropic element preferably has at least a discotic structural unit (preferably a discotic liquid crystal).

  The disc surface of the discotic structural unit is inclined with respect to the cellulose acylate film surface, and the angle formed by the disc surface of the discotic structural unit and the cellulose acylate film is the depth direction of the optical anisotropic layer. It is preferable that it changes in.

  The optical compensation film is particularly preferably used for a transmissive liquid crystal display device. The transmissive liquid crystal display device includes a liquid crystal cell and two polarizing plates disposed on both sides thereof. The liquid crystal cell carries a liquid crystal between two electrode substrates. One optical compensation film is disposed between the liquid crystal cell and one polarizing plate, or two optical compensation films are disposed between the liquid crystal cell and both polarizing plates. The mode of the liquid crystal cell is preferably a VA mode, a TN mode, or an OCB mode.

[Example 1]
An experiment was conducted to wind up a triacetylcellulose film having a width of 2000 mm and a thickness of 80 μm, which was formed on the film-forming line of FIG.

(Winding condition)
Experiment 1 is a case of winding without using the backup roller 30 and the suction nozzle 32.

  Experiment 2 is a case where the winding device 10 of the present embodiment described above is used. The clearance L1 between the backup roller 30 surface and the winding roll 28 surface is 3 mm, the clearance L2 between the backup roller 30 surface and the side 32B on the backup roller side of the suction nozzle 32 is 5 mm, and the side surface of the suction nozzle 32 on the winding roll 28 side. A gap L3 between 32C and the surface of the winding roll 28 was set to 5 mm. Further, the suction pressure of the suction nozzle 32 was set to 1100 Pa.

  Experiment 3 ... The backup roller 30 and the suction nozzle 32 are arranged as in Experiment 2, but the suction nozzle 32 is not sucked.

(Winding evaluation method)
As a winding evaluation method, winding tensions for obtaining the same “winding hardness” in Experiments 1 to 3 were compared. That is, it is necessary to set the winding hardness when experiment 1 is performed with a strong winding tension of 600 N as “reference winding hardness” and to make the winding hardness the same as “reference winding hardness” in experiments 2 and 3. The winding tension was examined.

(Test results)
As a result, in Experiment 2, even when the winding tension was reduced to 535 N, the same “reference winding hardness” as in Experiment 1 could be obtained. That is, in Experiment 2, the same winding hardness can be obtained even when the winding tension is reduced by 65 N compared to Experiment 1. Moreover, although the suction pressure by the suction nozzle 32 was increased to 1100 Pa, there was no fluttering of the film during winding.

  In Experiment 3, even when the winding tension was reduced to 560 N, the same “reference winding hardness” as in Experiment 1 could be obtained. That is, in Experiment 3, the same winding hardness can be obtained even if the winding tension is reduced by 40 N compared to Experiment 1.

  From this, even if it is a method that excludes the accompanying air with a suction nozzle, it is possible to increase the suction pressure so that the film does not flutter by configuring like the winding device 10 described in the present embodiment. It was found that hard winding can be performed by efficiently removing the accompanying wind.

  Further, as can be seen from the comparison of the winding tension between Experiment 2 and Experiment 3, the contribution of the suction nozzle 32 to the reduction of the winding tension is 25N, and the contribution of the backup roller 30 to the reduction of the winding tension is 40N. It can be seen that the contribution ratio of the backup roller 30 is large.

  DESCRIPTION OF SYMBOLS 10 ... Winding device, 12 ... Base film, 14 ... Film forming line, 16 ... Film forming part, 18 ... Winding shaft, 20 ... Knurling device, 22 ... Ear part cutting device, 24 ... Winding tension control device, 28 ... winding roll, 30 ... backup roller, 32 ... suction nozzle, 32A ... nozzle tip, 32B ... side of backup nozzle side of nozzle tip, 32C ... side of winding tip side of nozzle tip, 32D ... suction port , 34 ... moving means, 36 ... space, 38 ... support frame, 42 ... winding diameter sensor, 44 ... feed screw mechanism, 44A ... screw member, 44B ... servo motor, 44C ... nut member, 44D ... support plate, 44E ... Guide rod, 46 ... control unit

Claims (11)

In a film winding device that forms a winding roll by winding a traveling film on a winding shaft,
The film surface, which is arranged with a narrow first gap with respect to the winding roll surface and wraps and supports the film to be wound at a predetermined surface pressure or more, and the film surface supported by wrapping and the winding A backup roller that forms a triangular space between the roll surface and the winding start point as a vertex;
A nozzle tip portion having a triangular cross section is disposed in the space portion, and the air in the space portion is sucked with a suction pressure of a predetermined level or more, and the two side surfaces forming the triangular shape are the backup roller surface and the winding A suction nozzle disposed with a second gap and a third gap narrow with respect to the roll surface,
A moving means for integrally moving the backup roller and the suction nozzle while maintaining the gaps following the change in the winding diameter of the winding roll;
A film winding apparatus, wherein the film is wound and supported on the backup roller so that a surface pressure of the film surface supported by the winding is larger than a suction pressure of the suction nozzle.   The film winding apparatus according to claim 1, wherein the suction pressure by the suction nozzle is 200 to 1500 Pa.   3. The film winding apparatus according to claim 1, wherein the surface pressure is made larger than the suction pressure by increasing a wrap angle for winding and supporting the film on the backup roller.   The film winding apparatus according to claim 1 or 2, wherein a tension roller is used as the backup roller so that the surface pressure is larger than the suction pressure.   The film winding apparatus according to any one of claims 1 to 4, wherein a roller diameter of the backup roller is in a range of 20 to 150 mm.   The film winding apparatus according to any one of claims 1 to 5, wherein the first to third gaps are in a range of 0.5 to 10 mm.   Of the two side surfaces, the side surface on the backup roller side is formed on the same curvature surface as the curvature radius of the backup roller, and the side surface on the winding roll side has a curvature radius at the maximum winding diameter of the winding roll. The film winding device according to claim 1, wherein the film winding device is formed on the same curvature surface.   2. The backup roller and the suction nozzle are integrally supported by a support frame, and the support frame is formed with an opening through which an accompanying wind accompanying the film travel is released. The film winding apparatus according to any one of? 7. A base film winding step of winding the base film for manufacturing the optical film with the film winding device according to any one of claims 1 to 8;
An application step of rewinding the wound-up base film and applying an optical application liquid;
A method for producing an optical film, comprising: a drying step of drying the applied coating layer.   The method for producing an optical film according to claim 9, further comprising a product film winding step of winding the manufactured optical film with the film winding device according to claim 1.   The method for producing an optical film according to claim 9 or 10, wherein the optical film is any one of a polarizing plate protective film, an optical compensation film, and an antireflection film for a liquid crystal display device.

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