JP6269650B2 - Manufacturing method of optical film roll - Google Patents

Description

  The present invention relates to a method for producing an optical film roll.

  Resin films are used in various fields, such as liquid crystal display devices, in view of their chemical characteristics, mechanical characteristics, electrical characteristics, and the like. Specifically, various resin films, such as a transparent protective film for protecting the polarizing element of the polarizing plate, are disposed in the image display area of the liquid crystal display device. As such a resin film, for example, a resin film having excellent translucency such as a cellulose ester film is used.

  Such a resin film is generally manufactured as a long resin film by a solution casting film forming method, a melt casting film forming method, or the like, and is wound around a winding core (winding core) in a roll shape. It is used for storage and transportation. Moreover, when using a resin film, the resin film is drawn | fed out sequentially from the film roll with which the resin film was wound up by the roll core, and the resin film is used.

  On the other hand, the resin film is required to be widened. For example, in the case of a resin film used for a liquid crystal display device or the like, it is also required to widen the resin film in order to meet the demand for a large screen of the liquid crystal display device or the like. In addition, when using a resin film, the film roll wound with the resin film reduces the replacement frequency of the film roll and improves the working efficiency, so that the length of the resin film wound around the core ( Longer lengths are also required.

  The long resin film (film roll) wound up in such a roll shape has problems such as the end face of the wound resin film being displaced or the wound resin film being deformed. There was a thing. Moreover, with the widening and lengthening of the resin film, the occurrence of such problems has become more prominent. Therefore, a long resin film (film roll) wound up in such a roll shape is a deviation (winding shift) of the end surface of the wound resin film or a deformation (winding) of the wound resin film. In order to suppress the occurrence of deformation, etc., before winding into a roll shape, embossed portions are formed along the longitudinal direction at both ends in the width direction of the resin film, and the resin film on which the embossed portions are formed is wound. It is being considered to take.

  As a method for winding a resin film having an embossed portion around a core to produce a film roll, for example, the method described in Patent Document 1 can be mentioned.

  In Patent Document 1, after the straight winding step of winding the film around a core so that the side edges of the film are aligned, and after the straight winding step, the side edges are within a certain range with respect to the width direction of the film. The film winding method includes an oscillating winding step of periodically vibrating the film or the core in the width direction of the film so as to periodically shift the film and winding the film around the core. ing. Moreover, according to Patent Document 1, it is disclosed that an embossed portion is broken and a phenomenon that the both end portions (ear portions) of the film are extended in the width direction and an occurrence of winding deviation is not obtained. ing.

JP 2010-150041 A

  An object of this invention is to provide the manufacturing method of the optical film roll by which generation | occurrence | production of a deformation | transformation was fully suppressed even if preserve | saved for a long period of time.

  One aspect of the present invention includes a step of producing a long resin film having an embossed portion along the longitudinal direction at both ends in the width direction, and a winding step of winding the resin film into a roll around a core. And the winding step has an x-axis as the integrated thickness of the resin film being wound at the position of the resin film that starts to be wound around the core, and a center position in the width direction of the resin film, A sinusoidal vibration whose area surrounded by the function f (x) with the distance from the center position in the width direction of the winding core as the y-axis and the x-axis has the same amplitude and period as the f (x) Is larger than the area surrounded by the function a (x) and the x axis, and smaller than the area surrounded by the function b (x) of the rectangular wave vibration having the same amplitude and period as the f (x) and the x axis. So that at least one of the resin film and the core is Wherein while periodically vibrated in the width direction of the resin film, a method for producing an optical film roll comprising a vibration winding step of winding the resin film to the winding core.

  The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

FIG. 1 is a schematic view showing a winding device used in the method for producing an optical film roll according to this embodiment. FIG. 2 is a graph for explaining vibrations in the vibration winding process in the method of manufacturing an optical film roll according to the present embodiment. FIG. 3 is a schematic diagram showing the integrated emboss height in the width direction of the optical film roll. FIG. 4 is a schematic view showing a long resin film having an embossed portion and a film roll obtained by winding the resin film into a roll around a core. FIG. 5 is a drawing for explaining the shape of the embossed portion. FIG. 6 is a schematic diagram showing a basic configuration of an apparatus for producing a resin film by a solution casting film forming method. FIG. 7 is a schematic view showing a basic configuration of a resin film manufacturing apparatus using a melt casting film forming method. FIG. 8 is a schematic diagram showing a basic configuration of an optical film manufacturing apparatus. FIG. 9 is a graph for explaining the vibration in the vibration winding process in the example and the comparative example. FIG. 10 is a schematic diagram showing an outline of a configuration of a polarizing plate provided in a liquid crystal display device used for evaluation in Examples and Comparative Examples.

  The resin film is required not only to be wide and long, but also to be thin. For example, in the case of a resin film used for a liquid crystal display device or the like, it is also required to make the resin film thinner in order to meet the demand for thinning the liquid crystal display device or the like.

  When such a thinned resin film is wound around a core and made into a film roll, even if an embossed portion is formed at both ends in the width direction of the resin film before winding on the core, In some cases, the occurrence of winding deviation or winding deformation cannot be sufficiently suppressed. Specifically, in the film roll obtained by winding the core after forming the embossed part, the rise at both ends where the embossed part is formed becomes prominent, and deformation such as winding deviation and winding deformation occurs. Sometimes it was easy to do.

  According to the inventor's study, this is presumed to be due to the fact that the thinner the resin film, the lower the ratio of the thickness of the resin film to the height of the embossed part. In addition, it was assumed that the thinner the resin film, the weaker the resin film becomes and it becomes difficult to support the weight of the resin film. That is, it was guessed that the center part of the resin film in a film roll would hang down so that it might closely_contact | adhere to the resin film which exists directly under.

  On the other hand, if the oscillating winding is performed as in the winding method described in Patent Document 1, the overlap of the embossed portions at the same position in the width direction of the resin film can be reduced, thereby reducing the occurrence of the above problem. It is considered possible.

  However, even the winding method described in Patent Document 1 may not sufficiently suppress the occurrence of the above problem.

  The present inventor has inferred the reason why the occurrence of the above problem cannot be sufficiently suppressed even when the oscillating winding is performed as in the winding method described in Patent Document 1. Even in the case of oscillating winding as in the winding method described in Patent Document 1, if the oscillation of the oscillating winding is simply sinusoidal vibration, the region where the embossed portion in the width direction of the film roll exists It was inferred that the occurrence of problems such as deformation could not be sufficiently suppressed due to the fact that many embossed portions overlapped with the central portion. Therefore, the present inventor has arrived at the present invention as described below by examining in detail the vibration that changes the relative position between the resin film and the core when the film is wound.

  Hereinafter, although the embodiment concerning the present invention is described, the present invention is not limited to these.

  An optical film roll manufacturing method according to an embodiment of the present invention includes a resin film manufacturing process for manufacturing a long resin film having an embossed portion along the longitudinal direction at both ends in the width direction, and winding the resin film. A winding step of winding the core around a roll. In the winding step, the integrated thickness of the resin film being wound at the position of the resin film that starts to be wound around the core is defined as the x-axis, the center position in the width direction of the resin film, and the winding A function f (x) having the distance from the center position in the width direction of the core as a y-axis and the area surrounded by the x-axis is a function a of sinusoidal vibration having the same amplitude and cycle as the f (x). It is larger than the area surrounded by (x) and the x-axis and smaller than the area surrounded by the function b (x) of the rectangular wave vibration having the same amplitude and period as the f (x) and the x-axis. And a vibration winding step of winding the resin film around the core while periodically vibrating at least one of the resin film and the core in the width direction of the resin film.

  In the winding process including the above-described vibration winding process, the resin film manufactured in the resin film manufacturing process is wound up in a roll shape around the core, and even when stored for a long period of time, deformation is sufficient. It is possible to produce an optical film roll suppressed in the above. This is because the vibration that changes the relative position between the resin film and the core in the vibration winding step is embossed in the state of a film roll in which the resin film is wound around the core as described later. This is considered to be due to the vibration that effectively reduces the overlap of the parts.

  Moreover, the side shape of the obtained optical film roll becomes wavy by the vibration. The sharpness of the top of the convex portion of the wave shape becomes gentler when the side surface shape is the case of the vibration at f (x) than the case of the sinusoidal vibration. Therefore, the occurrence of damage to the side surface shape of the optical film roll can also be suppressed.

  The said resin film manufacturing process will not be specifically limited if it is a process of manufacturing the elongate resin film which has an embossing part along a longitudinal direction at the width direction both ends. Specifically, it will be described later.

  Next, the winding step is a step of winding the resin film in a roll shape around a core, and may be any step provided with a vibration winding step for causing vibration as described above. Moreover, a winding process is performed by the winding apparatus 10 as shown, for example in FIG. In addition, FIG. 1 is schematic which shows the winding apparatus 10 used for the manufacturing method of the optical film roll which concerns on this embodiment. 1A is a side view seen from the axial direction of the core 1 of the winding device 10, and FIG. 1B is a plan view seen from above the resin film 2. As shown in FIG.

  The winding device 10 includes a winding core 1, a rotating device (not shown), a guide roller 3, a vibration control device 4, a touch roller 6, and the like. The said winding core 1 winds up the resin film 2 on the surface, and becomes a shaft material of a film roll. The rotating device is a device for rotating the winding core 1. The guide roller 3 is a member that is disposed at a position in contact with the resin film 2 that has traveled, and is rotated by the travel of the resin film 2. The guide roller 3 can reduce the fluctuation of the travel position of the resin film 2 and can smoothly supply the resin film 2 to the core 1. Moreover, the winding of the resin film 2 around the core 1 is performed by rotating the core 1 by rotating the resin film 2 that has traveled to the surface of the core 1 with a rotating device, as shown in FIG. It is performed by winding up sequentially on the surface of the film. At the time of winding, in the vibration winding process, vibration is applied to change the relative position between the resin film and the core. The vibration control device 4 controls the vibration, which will be described later. The touch roller 6 is a member that rotates following the surface of the core 1 and the resin film 2 wound around the core 1 by rotating the core 1. The touch roller 6 can prevent the resin film 2 wound around the core 1 from being separated from the core 1.

  The vibration control device 4 vibrates the winding core 1 and controls the vibration to be the vibration. Hereinafter, the vibration will be described with reference to FIG. FIG. 2 is a graph for explaining vibrations in the vibration winding process in the method of manufacturing an optical film roll according to the present embodiment. In the present embodiment, the winding core is vibrated, but the relative position between the resin film and the winding core may be vibration as described above, and the resin film may be vibrated. Both the resin film and the winding core may be vibrated.

  First, the x-axis in the graph shown in FIG. 2 indicates the integrated thickness [mm] of the resin film being wound up at the position of the resin film that starts to be wound around the core. That is, the distance between the outermost surface of the wound resin film and the surface of the core at the position of the resin film that starts to be wound around the core, and corresponds to the integrated thickness x of the resin film shown in FIG. .

  2 is the distance between the center position of the resin film in the width direction and the center position of the core in the width direction (the distance between the centers of the resin film and the core) [mm]. Indicates. That is, the distance between the center position in the width direction of the resin film traveling toward the core and the center position in the width direction of the core is shown and corresponds to the center-to-center distance y shown in FIG.

  And the vibration in this embodiment is a vibration which becomes a function represented by the curve 51 shown in FIG. Specifically, a function f (x) representing vibration in the vibration winding process will be described with reference to FIG. First, the sinusoidal vibration having the same amplitude A and period T as f (x) is expressed as a function a (x) represented by a curve 52 shown in FIG. The vibration is such that Next, the rectangular wave vibration having the same amplitude A and period T as f (x) is expressed as a function b (x expressed by a curve 53 shown in FIG. ). Therefore, in the vibration winding process, the area surrounded by the function f (x) and the x axis is larger than the area surrounded by the function a (x) and the x axis, and the function b (x) The vibration is smaller than the area surrounded by the x-axis. That is, the vibration in the vibration winding process is such that f (x) exists between a (x) and b (x). When there is no vibration, the function in FIG. 2 is a function existing on the x-axis represented by a straight line 54.

  In addition, the height of each embossed part when the vibrations such as f (x) and a (x) as described above are performed or when the vibrations are not performed will be examined. In each case, the integrated height of the embossed part (integrated embossed height) is obtained by simulation. The result is shown in FIG. FIG. 3 is a schematic view showing the integrated emboss height in the width direction of the optical film roll. The x axis indicates the position of the optical film roll in the width direction, and the y axis indicates the integrated emboss height. When it is not vibrated, the graph shown by the line 57 is obtained. When it is not vibrated, it becomes a graph as shown by a line 57. From this, the embossed part is wound up at the same position, and the integrated embossed height is a value obtained by integrating the number of times of winding up to the height of the embossed part. Moreover, when it vibrates so that it may become said a (x) and the amplitude A in that case is below about the width | variety of an embossed part, it will become the graph shown by the line 56. FIG. In such a case, it can be seen that the embossed portion overlaps near the center position of the vibration amplitude A. On the other hand, when it vibrates so that it may become the said f (x), it will become the graph shown on the line 55. FIG. When it is vibrated to become f (x), the stay time when the absolute value of y displacement of vibration is large is relatively long, so in the state of the film roll in which the resin film is wound around the core, It can be seen that the vibration effectively reduces the overlap of the embossed portions. From this, if it is the manufacturing method of the optical film roll which concerns on this embodiment, even if it preserve | saves for a long period of time, if the resin film manufactured at the said resin film manufacturing process is wound up on a roll core, it will change, It is possible to produce an optical film roll in which the occurrence of is sufficiently suppressed.

  Further, the f (x) may be a function in which the vibration period T and the amplitude A fluctuate periodically. Specifically, the f (x) may be a periodic function in which f (x) = f (x + T) is satisfied, and the period T of the periodic vibration in the vibration winding process is an integral of the resin film. The relationship may be such that the thickness x gradually decreases as the thickness x increases. The vibration amplitude A in the vibration winding process may be a function that gradually increases as the integrated thickness x of the resin film increases.

  Moreover, it is preferable that the amplitude A of vibration in the vibration winding process gradually increases as the integrated thickness of the resin film increases. By doing so, an optical film roll in which the occurrence of deformation is further suppressed can be manufactured.

  First, it is considered that when the amplitude of vibration is large, the overlapping of the embossed portions can be further suppressed, and the occurrence of deformation can be further suppressed. However, the actually usable width of the resin film drawn out from the optical film roll and used is shortened. That is, the embossed portion and the portion that comes into contact with the embossed portion increase, and the width that can be used as a product is shortened.

  On the other hand, it is considered that as the resin film is wound around the core, the accumulated thickness of the wound resin film increases and deformation tends to occur.

  It is considered that the occurrence of deformation can be further suppressed by applying a vibration having a large amplitude that can further suppress the occurrence of deformation when the integrated thickness of the resin film is likely to occur. On the other hand, at the beginning of winding where deformation is unlikely to occur, it is considered that the occurrence of deformation can be sufficiently suppressed even when vibration having a small amplitude is applied. From these things, according to the above structures, it is thought that generation | occurrence | production of a deformation | transformation can be efficiently suppressed according to the integrated thickness of the resin film currently wound up. Therefore, it is considered that an optical film roll in which the occurrence of deformation is further suppressed can be manufactured.

  Moreover, it is preferable that the period T of vibration in the vibration winding process gradually decreases as the integrated thickness of the resin film increases. By doing so, generation | occurrence | production of a deformation | transformation can be suppressed more.

  First, if the period of vibration is small, winding deviation is likely to occur, but the load on the resin film can be reduced. Then, as the resin film is wound around the core, the integrated thickness of the wound resin film increases and deformation is likely to occur. It is considered that the occurrence of deformation can be further suppressed by applying a vibration having a small period that can reduce the load on the resin film when the integrated thickness of the resin film is likely to generate such deformation. From these things, according to said structure, it is thought that generation | occurrence | production of a deformation | transformation can be suppressed efficiently according to the thickness of integration of the resin film currently wound up.

  Moreover, the said winding process should just be equipped with the said vibration winding process, and all may be a vibration winding process, and may be provided with another winding process. Examples of other winding processes include a process of winding without changing the center distance y (non-vibrating winding process). Further, the non-vibrating winding process is preferably performed after the vibrating winding process. That is, it is preferable that the winding process includes the non-vibrating winding process after the vibrating winding process. When the optical film roll is manufactured, the resin film is wound up to the end by the vibration winding process, and when the resin film is started to be unwound from the obtained optical film roll, the resin film can be smoothly unwound by meandering of the resin film. There was no case. As described above, if the non-vibration winding process is provided after the vibration winding process, an optical film roll capable of smoothly feeding the resin film immediately after the start of feeding can be obtained. That is, since the winding without vibration as described above is performed after the vibration winding process, it is possible to suppress the problem of unwinding that may occur immediately after the start of unwinding of the resin film. It is possible to suppress deformation of the optical film roll at the portion where the film is wound.

  Moreover, the said resin film manufacturing process is a process which can manufacture the elongate resin film 2 which has the embossing part 5 along a longitudinal direction in both ends of a width direction, as shown to Fig.4 (a). If there is, it will not be specifically limited. That is, any method may be used as long as the predetermined embossed portion 5 is formed on the resin film. Specifically, a method of forming an embossed part by pressing a roller such as an embossing ring against the resin film can be used. In addition to the method of forming the embossed portion by such a contact method, a method of forming the embossed portion by a non-contact method can be mentioned. As a method of forming the embossed portion by this non-contact method, a resin film is irradiated with laser light to form an embossed portion, or a liquid material for forming the embossed portion is formed by an inkjet method. The method etc. which form an embossed part by apply | coating are mentioned.

  FIG. 4 is a schematic view showing a long resin film having an embossed portion and a film roll obtained by winding the resin film into a roll around a core. FIG. 4A shows an example of a resin film, and FIG. 4B shows an example of a film roll. As shown in FIG. 4A, the resin film 2 is a long resin film 2 having embossed portions 5 along the longitudinal direction at both ends in the width direction. Moreover, as shown in FIG.4 (b), the film roll 7 is the film roll 7 which wound up the resin film 2 around the core 1 in roll shape. And the area | region where the embossed part 5 of the resin film 2 overlaps becomes thicker than the area | region where other than the embossed part 5 overlaps. This thickness difference L depends on the integrated emboss height. That is, the thickness difference L is smaller by performing the vibration winding process according to the present embodiment than when the vibration winding process is not performed.

  Moreover, the embossed part 5 formed by the said resin film manufacturing process should just be formed in the width direction both ends of the resin film 2 along the longitudinal direction. Although it does not specifically limit with the width direction both ends of the resin film 2, For example, the area | region etc. which are about 0.5-30 mm from the outer edge of a resin film are mentioned. Moreover, the width direction both ends of the resin film 2 include, for example, a region that occupies about 0.2 to 6% of the width of the resin film from the outer edge of the resin film. If the width of the embossed portion is too narrow, the transportability of the resin film tends not to be sufficiently improved. Moreover, when the width | variety of an embossed part is too wide, the area of the area | region in which the embossed part is not formed, ie, a part utilized as an optical film, will become narrow.

  Moreover, although the height of an embossed part is not specifically limited, It is preferable that it is about 1-20 mm. If the embossed portion is too low, the effect of the embossed portion, such as suppressing winding slippage in the film roll state, tends to be insufficient. In addition, if the embossed portion is too high, the region where the embossed portion of the resin film overlaps becomes too thicker than the region where the embossed portion overlaps, and even if the vibration winding process according to this embodiment is performed, the obtained film roll There is a tendency that the effect of suppressing the deformation cannot be sufficiently exhibited.

  Moreover, the shape of the embossed part 5 formed by the said resin film manufacturing process is not specifically limited. Specifically, a shape as shown in FIG. 5 is mentioned. FIG. 5 is a drawing for explaining the shape of the embossed portion. Examples of the shape of the embossed portion 5 include the following shapes. Specifically, the cross-sectional shape of the embossed part 5 is a rectangular shape as shown in FIG. Moreover, as shown in FIG.5 (b), the thing of the shape where the recessed part 5a in which the width direction both ends of the embossed part 5 became low in the width direction center part of the embossed part 5 was formed is mentioned. Moreover, what has the some convex part 5b, 5c as the embossing part 5 is shown to FIG.5 (c) is mentioned. In such a case, among the plurality of convex portions 5 b and 5 c, the convex portion 5 b existing at the center in the width direction of the embossed portion 5 is lower than the convex portion 5 c existing at the center in the width direction of the embossed portion 5. The embossed part formed in this way is preferable. If it is such an embossed part, the film roll which can suppress generation | occurrence | production of a deformation | transformation will be obtained. This is considered to be due to the following. When winding the resin film, even if the vibration winding process is applied, the overlap of the embossed portion in the center in the width direction is larger than the end portion of the embossed portion. If the convex part 5b which exists in the width direction center part of the embossed part 5 as mentioned above is a low embossed part, it is thought that the overlap of the width direction center part of an embossed part can be decreased. By this, the film roll which can contribute to the reduction | decrease of the thickness of the embossing part in a film roll, and suppressed the deformation | transformation more is obtained. Moreover, although the both ends and center part in an embossed part are not specifically limited, The area | region which occupies about 40 to 80% with respect to the width | variety of an embossed part from the outer edge of an embossed part etc. is mentioned, for example. .

  Further, the embossed portion may be cut before being used as an optical film or the like, and is actually often cut. Therefore, the material of the embossed part is not particularly limited as long as the effect of the embossed part such as suppressing the winding deviation in the film roll state can be sufficiently exhibited.

  Moreover, the thickness of the resin film is not particularly limited, but the resin film is required to be thin. In order to satisfy this requirement, the thickness of the resin film is preferably 10 to 35 μm. Moreover, if it is a resin film of such thickness, since it is thinner than the conventional resin film, the winding length of an optical film roll can also be lengthened. On the other hand, such a thin resin film is prone to deformation of a film roll obtained by winding it into a roll shape. An optical film roll whose generation is sufficiently suppressed is obtained. From these things, it is preferable that the thickness of a resin film is 10-35 micrometers which is said range. Here, the thickness is an average value of the thickness, 20 to 200 locations in the width direction of the film are measured with a contact-type film thickness meter manufactured by Mitutoyo Corporation, and the average value of the measured values is the thickness. As shown. Moreover, the width | variety of a resin film is not specifically limited, For example, it is preferable that it is 1000-4000 mm.

  Moreover, in the said resin film manufacturing process, the resin film which forms an embossed part is not specifically limited. The resin film may be, for example, a resin film that is not subjected to any treatment on a resin film made of a transparent resin, or may be a resin film other than that. Specifically, as the resin film, the following resin films used in the optical field can be preferably used.

  The resin film is preferably an optical film used as a polarizing plate protective film. When an optical film roll is manufactured by the optical film roll manufacturing method according to the present embodiment using the optical film used as such a polarizing plate protective film as a resin film, the occurrence of problems due to the deformation of the optical film roll is sufficient. An optical film roll capable of sequentially feeding and providing the suppressed optical film is obtained.

  The resin film is preferably a retardation film used as an optical compensation film for a liquid crystal display device. When a retardation film used as an optical compensation film for such a liquid crystal display device is used as a resin film, and an optical film roll is manufactured by the method for manufacturing an optical film roll according to this embodiment, a defect due to deformation of the optical film roll Thus, an optical film roll capable of sequentially feeding out and providing a retardation film in which the occurrence of the above is sufficiently suppressed is obtained.

  Moreover, it is preferable that it is an optical film provided with a base film and a functional layer which exists on the said base film as said resin film. This base film is not specifically limited, For example, the resin film etc. which have not performed any process with respect to the resin film which consists of transparent resin are mentioned. Moreover, if a functional layer is used as a functional layer of an optical film, it will not be specifically limited. When such an optical film is used as a resin film and an optical film roll is manufactured by the method for manufacturing an optical film roll according to the present embodiment, optical films in which occurrence of defects due to deformation of the optical film roll is sufficiently suppressed are sequentially provided. An optical film roll that can be fed out and provided is obtained. Moreover, since the said optical film is equipped with a base film and a functional layer at least, the deformation | transformation by dead weight tends to occur. Even when such an optical film is used as a resin film, an optical film roll in which the occurrence of deformation is sufficiently suppressed can be obtained by manufacturing the optical film roll by the method for manufacturing an optical film roll according to this embodiment. .

(Solution casting film forming method)
Moreover, as a specific example of the said resin film manufacturing process, the method of manufacturing a resin film by the following solution casting film forming methods etc. are mentioned, for example.

  A method for producing a resin film by a solution casting film forming method includes a casting step of casting a resin solution (dope) containing a transparent resin on a traveling support to form the film, Examples of the method include a peeling step of peeling from the support and a drying step of drying the film by transporting the peeled film with a plurality of transport rollers. Furthermore, the method for producing the resin film includes an embossed portion forming step for forming an embossed portion on the film between the peeling step and the drying step or after the drying step. For example, it is performed by a resin film manufacturing apparatus as shown in FIG. In addition, as a manufacturing apparatus of a resin film, if the said each process is performed, it will not specifically limit to what is shown in FIG. 6, The thing of another structure may be sufficient. Here, the film means a film after a cast film (web) made of a dope cast on a support is dried on the support and can be peeled off from the support.

  FIG. 6 is a schematic diagram showing a basic configuration of an apparatus for producing a resin film by a solution casting film forming method. The resin film manufacturing apparatus 11 includes an endless belt support 12, a casting die 13, a peeling roller 14, a stretching apparatus 15, a drying apparatus 17, an embossed part forming apparatus 18, a winding apparatus 10, and the like. The casting die 13 casts a resin solution (dope) 19 in which a transparent resin is dissolved onto the surface of the endless belt support 12. The endless belt support 12 is formed into a film by forming a web made of the dope 19 cast from the casting die 13 and drying it while being conveyed. The peeling roller 14 peels the film from the endless belt support 12. The stretching device 15 stretches the peeled film. The drying device 17 dries the stretched film while being transported by a transport roller. The embossed part forming device 18 forms an embossed part at the end of the dried film. The said winding apparatus 10 winds up the film in which the embossed part was formed, and makes it a film roll.

  As shown in FIG. 6, the casting die 13 is supplied with a dope 19 from a dope supply pipe connected to an upper end portion of the casting die 13. Then, the supplied dope is discharged from the casting die 13 to the endless belt support 12, and a web is formed on the endless belt support 12.

  As shown in FIG. 6, the endless belt support 12 is a metal endless belt having a mirror surface and traveling infinitely. As the belt, for example, a belt made of stainless steel or the like is preferably used from the viewpoint of peelability of the film. The width of the casting film cast by the casting die 13 is preferably 80 to 99% with respect to the width of the endless belt support 12 from the viewpoint of effectively utilizing the width of the endless belt support 12. . And in order to finally obtain a resin film with a width of 1000 to 4000 mm, the width of the endless belt support 12 is preferably 1800 to 5000 mm. Further, instead of the endless belt support, a rotating metal drum (endless drum support) having a mirror surface may be used.

  And the said endless belt support body 12 dries the solvent in dope, conveying the cast film (web) formed on the surface. The drying is performed, for example, by heating the endless belt support 12 or blowing heated air on the web. At that time, although the temperature of the web varies depending on the dope solution, the range of −5 to 70 ° C. is preferable and the range of 0 to 60 ° C. is preferable in consideration of the conveyance speed and productivity accompanying the evaporation time of the solvent. More preferred. The higher the temperature of the web, the faster the solvent can be dried. However, when the temperature is too high, the web tends to foam or the flatness tends to deteriorate.

  When heating the endless belt support 12, for example, a method of heating the web on the endless belt support 12 with an infrared heater, a method of heating the back of the endless belt support 12 with an infrared heater, the back of the endless belt support 12 And a method of heating by blowing heated air, and the like can be selected as needed.

  In addition, when blowing heated air, the wind pressure of the heated air is preferably 50 to 5000 Pa in consideration of the uniformity of solvent evaporation and the like. The temperature of the heating air may be dried at a constant temperature, or may be supplied in several steps in the running direction of the endless belt support 12.

  The time between casting the dope on the endless belt support 12 and peeling the web from the endless belt support 12 varies depending on the thickness of the optical film to be produced and the solvent used. Considering the peelability from the support 12, it is preferably in the range of 0.5 to 5 minutes.

  The transport speed of the cast film by the endless belt support 12 is preferably about 50 to 200 m / min, for example. Moreover, it is preferable that ratio (draft ratio) of the conveyance speed of the cast film with respect to the traveling speed of the endless belt support 12 is about 0.8 to 1.2. When the draft ratio is within this range, the cast film can be stably formed. For example, if the draft ratio is too large, there is a tendency to cause a phenomenon called neck-in in which the cast film is reduced in the width direction, and if so, a wide film cannot be formed.

  The peeling roller 14 is in contact with the surface of the endless belt support 12 on which the dope 19 is cast, and the dried web (film) is peeled by applying pressure to the endless belt support 12 side. . When the film is peeled from the endless belt support 12, the film is stretched in the film transport direction (machine direction: MD direction) by the peeling tension and the subsequent transport tension. For this reason, it is preferable that the peeling tension and the conveyance tension when peeling the film from the endless belt support 12 are 30 to 400 N / m.

  Further, the total residual solvent amount of the film when the film is peeled off from the endless belt support 12 is formed after the peelability from the endless belt support 12, the residual solvent amount at the time of peeling, the transportability after peeling, and the transport / drying. In consideration of physical properties of the optical film, the content is preferably 10 to 200% by mass.

  The stretching device 15 stretches the film peeled from the endless belt support 12 in a direction (Transverse Direction: TD direction) orthogonal to the web conveyance direction. Specifically, both ends in a direction perpendicular to the film transport direction are gripped with a clip or the like, and the distance between the opposing clips is increased to extend in the TD direction. And the said extending | stretching apparatus 15 may be equipped with the apparatus which cut | disconnects the area | region which was holding the clip. Moreover, although the extending | stretching apparatus 15 was provided here, it does not need to be provided.

  The drying device 17 includes a plurality of transport rollers, and dries the film while transporting the film between the rollers. In that case, you may dry using heating air, infrared rays, etc. independently, and you may dry using heating air and infrared rays together. It is preferable to use heated air from the viewpoint of simplicity. The drying temperature varies depending on the amount of residual solvent in the film, but is determined by appropriately selecting the amount of residual solvent in the range of 30 to 180 ° C. in consideration of drying time, shrinkage unevenness, stability of the amount of expansion and contraction, etc. That's fine. Moreover, it may be dried at a constant temperature, or may be divided into two to four stages of temperature, and may be divided into several stages of temperature. Further, the film can be stretched in the MD direction while being conveyed in the drying device 17. The amount of residual solvent in the film after the drying treatment in the drying device 17 is preferably 0.001 to 5% by mass in consideration of the load of the drying process, the dimensional stability expansion / contraction ratio during storage, and the like.

  The embossed part forming device 18 forms embossed parts at both ends (widthwise direction) perpendicular to the film transport direction during transport of the film. The shape and width of the embossed portion may be the shape and width described above. In addition, as described above, the embossed portion may be formed by a contact method or a non-contact method.

  The winding device 10 may be the winding device described above. Specifically, the winding apparatus etc. which can perform the said vibration winding process are mentioned.

  Hereinafter, the composition of the resin solution used in the solution casting film forming method will be described.

  The transparent resin used in the solution casting film forming method is not particularly limited as long as it is a resin having transparency when formed into a film shape, but is easy to manufacture by the solution casting film forming method or the like. In particular, it is preferable to have excellent adhesion to a hard coat layer and the like, and to be optically isotropic. Here, the transparency means that the visible light transmittance is 60% or more, preferably 80% or more, and more preferably 90% or more.

  Specific examples of the transparent resin include cellulose ester resins such as cellulose triacetate resin. Further, the dope used here may contain fine particles. The fine particles may be inorganic fine particles such as silicon oxide or organic fine particles such as acrylic resin. As the solvent used here, a solvent containing a good solvent for the transparent resin can be used, and a poor solvent may be contained as long as the transparent resin does not precipitate. Examples of the good solvent for the cellulose ester resin include organic halogen compounds such as methylene chloride. Moreover, as a poor solvent with respect to a cellulose-ester-type resin, C1-C8 alcohols, such as methanol, etc. are mentioned, for example. The resin solution used here may contain other components (additives) other than the transparent resin, fine particles and solvent as long as the effects of the present invention are not impaired. Examples of the additive include a plasticizer, an antioxidant, an ultraviolet absorber, a heat stabilizer, a conductive substance, a flame retardant, a lubricant, and a matting agent.

  Moreover, the solution of a cellulose-ester-type resin is obtained by mixing said each composition. The obtained cellulose ester resin solution is preferably filtered using a suitable filter medium such as filter paper.

  In addition, when the resin film is a retardation film used as an optical compensation film for a liquid crystal display device as described above, the resin solution used in the solution casting film forming method is obtained by stretching or the like. The resin solution is not particularly limited as long as it can be obtained.

(Melt casting method)
Moreover, as another specific example of the said resin film manufacturing process, the method etc. which manufacture a resin film by the following melt casting film forming methods etc. are mentioned, for example.

  A method for producing a resin film by a melt casting film forming method includes a casting step of casting a resin melt obtained by melting a transparent resin on a traveling support to form a casting film, and the casting A cooling step of cooling the film to form a film; a peeling step of peeling the film from the support; and a stretching step of stretching the film by transporting the peeled film with a plurality of transport rollers. Methods and the like. Furthermore, the method for producing the resin film includes an embossed portion forming step for forming an embossed portion on the film between the peeling step and the stretching step, after the stretching step, or the like. For example, it is performed by a resin film manufacturing apparatus as shown in FIG. The resin film manufacturing apparatus is not particularly limited to the one shown in FIG. 7 as long as it performs the above-described steps, and may have other configurations. Here, the term “film” refers to a film after a cast film (web) made of a dope cast on a support is cooled on the support and can be peeled off from the support.

  FIG. 7 is a schematic view showing a basic configuration of a resin film manufacturing apparatus using a melt casting film forming method. The resin film manufacturing apparatus 21 includes a first cooling roller 22, a casting die 23, a surface correction touch roller 24, a second cooling roller 25, a third cooling roller 26, a peeling roller 27, a conveying roller 29, a stretching apparatus 30, an embossing A part forming device 31 and a winding device 10 are provided. The casting die 23 casts a resin melt (dope) obtained by melting a transparent resin onto the surface of the first cooling roller 22. The first cooling roller 22 forms a casting film made of dope cast from the casting die 23, cools the casting film while transporting it, and transports the casting film to the second cooling roller 25. At that time, the thickness of the cast film is adjusted and the surface is smoothed by the surface correction touch roller 24 provided to circumscribe the first cooling roller 22. The second cooling roller 25 cools the cast film while transporting the cast film, and transports the cast film to the third cooling roller 26. By so doing, the cast film is used as a film. The peeling roller 27 peels the film from the third cooling roller 26. The transport roller 29 extends in the MD direction while transporting the peeled film. The stretching device 30 stretches the film in the TD direction. The embossed part forming device 31 forms an embossed part at the end of the stretched film. The winding device 10 winds the cooled and solidified film to form a film roll.

  The casting die 23 has the same configuration as the casting die 13 except that a resin melt is discharged as a dope instead of a resin solution.

  The first cooling roller 22, the second cooling roller 25, and the third cooling roller 26 are metal rollers having a mirror surface. As each of the rollers, for example, a roller made of stainless steel or the like is preferably used from the viewpoint of peelability of a cast film or a film. The width of the cast film cast by the casting die 23, the transport speed of the cast film by the first cooling roller 22, the second cooling roller 25, and the third cooling roller 26, etc. Same as the case.

  The surface correction touch roller 24 has an elastic surface, and is deformed along the surface of the first cooling roller 22 by the pressing force to the first cooling roller 22, and between the first cooling roller 22 and the surface correction touch roller 24. A nip is formed. As the surface correction touch roller 24, any touch roller conventionally used in the melt casting film forming method can be used without any particular limitation. Specifically, the thing made from stainless steel is mentioned, for example.

  The peeling roller 27 is in contact with the third cooling roller 26, and the film is peeled by applying pressure.

  The conveyance roller 29 includes a plurality of conveyance rollers, and can be stretched in the MD direction of the film by setting different rotation speeds for each conveyance roller.

  Moreover, the said extending | stretching apparatus 30 and the said embossed part formation apparatus 31 can use the thing similar to the said extending | stretching apparatus 15 and the embossed part forming apparatus 18. FIG.

  Moreover, the said winding apparatus 10 can mention the winding apparatus etc. which can perform the said vibration winding process similarly to the case of the solution casting film forming method.

  Hereinafter, the composition of the resin melt used in the melt casting film forming method will be described.

  The transparent resin used in the melt casting film forming method can be the same as the transparent resin in the solution casting film forming method as long as it can be heated and melted. Also, other compositions can be used as in the case of the solution casting film forming method.

(Functional layer formation)
Moreover, as a resin film, it is preferable that it is an optical film provided with a base film and the functional layer which exists on the said base film as mentioned above. In order to obtain such an optical film, the following methods are exemplified. Examples of the base film include a resin film obtained without forming an embossed part by the solution casting film forming method or the melt casting film forming method as described above. Moreover, a functional layer will not be specifically limited if it is used as a functional layer of an optical film. Specifically, it will be described later.

  Examples of a method for producing an optical film having such a functional layer include, for example, a coating process in which a liquid resin composition is applied to at least one surface of a base film, and a function in which the resin composition is cured or dried. And a method including a layer forming step of forming a layer. Furthermore, this optical film manufacturing method includes an embossed portion forming step of forming an embossed portion on the film after the layer forming step. For example, it is performed by an optical film manufacturing apparatus as shown in FIG. In addition, as an optical film manufacturing apparatus, it is not limited to what is shown in FIG. 8, The thing of another structure may be sufficient.

  FIG. 8 is a schematic diagram showing a basic configuration of an optical film manufacturing apparatus. The optical film manufacturing apparatus 41 includes an unwinding apparatus 42, a coating apparatus 43, a drying apparatus 44, a curing apparatus 45, an embossed part forming apparatus 46, a winding apparatus 10, and the like.

  The unwinding device 42 supplies the base film to the coating device 43 and the like. The unwinding device 42 includes, for example, an unwinding roller wound so as to be able to unwind a base film, and supplies the base film to the coating device 43 and the like by rotating the unwinding roller. is there.

  The coating device 43 applies a liquid resin composition onto the surface of the base film supplied from the unwinding device 42. The coating device 43 can use a general coating device without limitation. For example, an extrusion method, a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a rod coating method, a gravure coating method, and an inkjet method. And the like. In addition, when a plurality of layers are applied and formed on a base film, multiple layers may be simultaneously applied with a single application device, such as an extrusion die having a multi-manifold, or a single layer may be applied. A plurality of apparatuses may be arranged side by side and applied sequentially. In the present embodiment, the step of applying the liquid resin composition by the applying device 43 corresponds to the applying step.

  The drying device 44 dries the liquid resin composition applied on the base film. The drying device 44 may employ, for example, a convection drying method using hot air, a radiant drying method using radiant heat such as infrared rays, or the like. Note that the drying device 44 may not be completely dried.

  The curing device 45 cures the liquid resin composition applied on the base film. The curing device 45 differs depending on whether the liquid resin composition contains an active ray curable resin such as an ultraviolet curable resin or an electron beam curable resin or a thermosetting resin. Specifically, for example, when the liquid resin composition contains an actinic radiation curable resin, an actinic radiation irradiation apparatus such as an ultraviolet irradiation apparatus can be used. Moreover, when a liquid resin composition contains a thermosetting resin, a heat treatment apparatus is mentioned.

  The embossed part forming apparatus 46 may be the same as the embossed part forming apparatus 18. Here, the surface on which the embossed portion is formed may be the side on which the resin composition is applied, or the side on which the embossed portion is not applied. Moreover, both sides may be sufficient.

  Moreover, the said winding apparatus 10 can mention the winding apparatus etc. which can perform the said vibration winding process similarly to the case of the solution casting film forming method and the melt casting film forming method. The winding device 10 may not include a touch roller, and here, a winding device that does not include a touch roller is used.

  Moreover, as long as a functional layer is used as a functional layer of an optical film as above-mentioned, it will not specifically limit. Specifically, first, the following hard coat layers and the like can be mentioned.

(Hard coat layer)
As the hard coat layer, one containing an actinic radiation curable resin is preferably used in that it has excellent mechanical film strength such as scratch resistance and pencil hardness. That is, examples of the hard coat layer include a layer mainly composed of an actinic radiation curable resin that has been cured through a crosslinking reaction by irradiation with actinic rays (also referred to as actinic energy rays) such as ultraviolet rays and electron beams.

  The actinic radiation curable resin is preferably a resin obtained using a component containing a monomer having an ethylenically unsaturated double bond. That is, when the hard coat layer is a layer containing the active ray curable resin as a main component, a component containing a monomer having an ethylenically unsaturated double bond is polymerized and cured by irradiation with the active ray. It is preferable that it is the obtained active ray curable resin layer.

  As the actinic radiation curable resin, an actinic radiation curable resin obtained by polymerizing and curing actinic radiation curable compounds such as an ultraviolet curable compound cured by ultraviolet irradiation and an electron beam curable compound cured by electron beam irradiation. Is a typical example. Among these, an actinic radiation curable resin obtained by curing by ultraviolet irradiation is particularly preferable from the viewpoint of excellent mechanical film strength (abrasion resistance, pencil hardness).

  The ultraviolet curable compound is not particularly limited as long as an actinic radiation curable resin that is polymerized and cured by ultraviolet irradiation can be obtained. Specifically, the ultraviolet curable compound includes an ultraviolet curable acrylate compound, an ultraviolet curable urethane acrylate compound, an ultraviolet curable polyester acrylate compound, an ultraviolet curable epoxy acrylate compound, and an ultraviolet curable polyol acrylate compound. A compound or an ultraviolet curable epoxy compound is preferably used. Among these, an ultraviolet curable acrylate compound or an ultraviolet curable urethane acrylate compound is preferable.

  Moreover, as an ultraviolet curable acrylate type compound, polyfunctional acrylate is preferable. The polyfunctional acrylate is preferably selected from the group consisting of, for example, pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups or methacryloyloxy groups in the molecule. More specifically, polyfunctional acrylates include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylol. Methane triacrylate, tetramethylol methane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tri / tetraacrylate, ditrimethylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, pentaerythritol tetraacrylate, Glycerin triacrease , Dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol di Methacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, tetramethylolmethane trimethacrylate, tetramethylolmethane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pen Pentaerythritol tetramethacrylate, glycerol trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexa methacrylate, etc. isocyanurate derivatives of the active energy ray-curable are preferably exemplified. Among these, active energy ray-curable isocyanurate derivatives are preferably used.

  The active energy ray-curable isocyanurate derivative is not particularly limited as long as it is a compound having a structure in which one or more ethylenically unsaturated groups are bonded to the isocyanuric acid skeleton, but there are three or more in the same molecule. Compounds having an ethylenically unsaturated group and one or more isocyanurate rings are preferred. Specifically, a compound represented by the following general formula (1) is preferably used. Moreover, it does not specifically limit as an ethylenically unsaturated group, For example, an acryloyl group, a methacryloyl group, a styryl group, a vinyl ether group etc. are mentioned. Among these, a methacryloyl group or an acryloyl group is preferable, and an acryloyl group is particularly preferable.

The formula (1), ^{L 2} is a divalent linking group. Specific examples of L ² include a substituted or unsubstituted alkyleneoxy group having 4 or less carbon atoms in which a carbon atom is bonded to an isocyanurate ring, or a polyalkyleneoxy group. Among these, the said alkyleneoxy group is preferable. L ² may be the same or different. R ² independently represents a hydrogen atom or a methyl group.

  Specific examples of the compound represented by the general formula (1) are shown below, but the compound represented by the general formula (1) is not limited thereto.

  Examples of other compounds of the active energy ray-curable isocyanurate derivative include isocyanuric acid diacrylate compounds, and isocyanuric acid ethoxy-modified diacrylate is preferably used. Specific examples include compounds represented by the following general formula (2).

  Further, as other compounds of the active energy ray-curable isocyanurate derivative, an ε-caprolactone-modified active energy ray-curable isocyanurate derivative can also be exemplified. Specific examples include compounds represented by the following general formula (3).

In said formula (3), R < ₁ > -R < ₃ > shows either of the functional groups shown by the following a, b, and c each independently. _Further, at least one of R 1 to R ₃ represents a functional group represented by the following b.

a is, -H, or _- (CH 2) n-OH is (n = 1 to 10, preferably n = 2 to 6).

b _is - _{(CH 2) n-O- (} COC 5 H 10) m-COCH = CH 2 (n = 1~10, preferably n = 2~6, m = 2~8) .

c is — (CH ₂ ) n—O—R (R is a (meth) acryloyl group, n = 1 to 10, preferably n = 2 to 6).

  Specific examples of the compound represented by the general formula (3) are shown below, but the compound represented by the general formula (3) is not limited thereto.

  Examples of commercially available isocyanuric acid triacrylate compounds include A-9300 manufactured by Shin-Nakamura Chemical Co., Ltd. Examples of commercially available isocyanuric acid diacrylate compounds include Aronix M-215 manufactured by Toagosei Co., Ltd. As a commercial item of the mixture of an isocyanuric-acid triacrylate compound and an isocyanuric-acid diacrylate compound, Toagosei Co., Ltd. product, Aronix M-315, Aronix M-313, etc. are mentioned, for example. Examples of the ε-caprolactone-modified active energy ray-curable isocyanurate derivatives include ε-caprolactone-modified tris- (acryloxyethyl) isocyanurate. As this commercial item, A-9300-1CL by Shin-Nakamura Chemical Co., Ltd., Aronix M-327 by Toagosei Co., Ltd., etc. can be mentioned. Examples of commercially available active energy ray-curable isocyanurate derivatives include, but are not limited to, those described above.

  Commercially available active energy ray-curable isocyanurate derivatives include Adekaoptomer N series, Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC- 612 (manufactured by Sanyo Chemical Industries), Aronix M-6100, M-8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (manufactured by Toagosei Co., Ltd.) ), NK-ester A-TMM-3L, NK-ester AD-TMP, NK-ester ATM-35E, NK ester A-DOG, NK ester A-IBD-2E, A-9300, A-9300-1CL (new) Nakamura Chemical Co., Ltd.), PE-3A (Kyoeisha Chemical), etc. are also mentioned.

  Further, as the ultraviolet curable urethane acrylate compound, for example, an ultraviolet curable compound which is a polyurethane compound obtained by reacting an alcohol, a polyol, and / or a hydroxyl group-containing compound such as a hydroxyl group-containing acrylate with isocyanates. Examples thereof include urethane acrylate resins. Further, the ultraviolet curable urethane acrylate resin may be an ultraviolet curable urethane acrylate resin obtained by esterifying the polyurethane compound with (meth) acrylic acid, if necessary. More specifically, an addition reaction product of polyisocyanate and an acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule may be mentioned.

  Examples of polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4 ′. -Aromatic isocyanates such as diphenylmethane diisocyanate. Other examples of polyisocyanates include, for example, compounds having two isocyanate groups bonded to alicyclic hydrocarbons such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, norbornane diisocyanate, 1,4-cyclohexane diisocyanate (hereinafter, Abbreviated as alicyclic diisocyanate), compounds having two isocyanate groups bonded to aliphatic hydrocarbons such as trimethylene diisocyanate and hexamethylene diisocyanate (hereinafter abbreviated as aliphatic diisocyanate), phenylene diisocyanate, toluene diisocyanate, etc. Aromatic diisocyanates such as aromatic diisocyanates and xylylene diisocyanates. These polyisocyanates can be used alone or in combination of two or more. The polyisocyanate is preferably an aliphatic diisocyanate or an alicyclic diisocyanate among the compounds exemplified above, and is preferably isophorone diisocyanate, norbornane diisocyanate, toluene diisocyanate or hexamethylene diisocyanate.

  Examples of acrylates having one hydroxy group and one or more (meth) acryloyl groups in one molecule include trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) And polyacrylates of polyvalent hydroxy group-containing compounds such as acrylates. Other examples of the acrylate include an adduct of the polyacrylate and ε-caprolactone, an adduct of the polyacrylate and an alkylene oxide, and the like. Moreover, epoxy acrylates etc. are mentioned as another example of the said acrylate. The acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule can be used alone or in combination of two or more.

  As the acrylate having one hydroxy group and one or more (meth) acryloyl groups in one molecule, an acrylate having one hydroxy group and 3 to 5 (meth) acryloyl groups in one molecule is preferable. Examples of such acrylates include pentaerythritol triacrylate and dipentaerythritol pentaacrylate.

  Moreover, as a specific product of the ultraviolet curable urethane acrylate-based resin, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Purple UV-1700B, UV-6300B, UV-7600B, UV-7630B, UV-7630B, UV-7640B, Kyoeisha Chemical Co., Ltd. UA-306H, UA-306T, UA-306I, UA-510H, Shin Nakamura Chemical Industry Co., Ltd. NK Oligo UA-1100H, NK Oligo UA-53H, NK Oligo UA-33H, NK oligo UA-15HA etc. are mentioned.

  The viscosity of the actinic radiation curable resin can be measured using a B-type viscometer under the condition of 25 ° C. while the resin is stirred and mixed with a disper.

  Moreover, when obtaining the said active ray curable resin, you may use a monofunctional acrylate in addition to the said polyfunctional acrylate etc.

  Examples of monofunctional acrylates include isobornyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, isostearyl acrylate, benzyl acrylate, ethyl carbitol acrylate, phenoxyethyl acrylate, lauryl acrylate, isooctyl acrylate, and tetrahydrofurfuryl acrylate. , Behenyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, cyclohexyl acrylate and the like. Such monofunctional acrylates can be obtained from Nippon Kasei Kogyo Co., Ltd., Shin-Nakamura Chemical Co., Ltd., Osaka Organic Chemical Co., Ltd., etc.

  When using a monofunctional acrylate, it is preferable to contain in the range of polyfunctional acrylate: monofunctional acrylate = 80: 20-98: 2 by the mass ratio of polyfunctional acrylate and monofunctional acrylate.

(Photopolymerization initiator)
Further, when producing the hard coat layer, in addition to the above-mentioned polyfunctional acrylate which is a raw material of the actinic radiation curable resin which can be the main component of the hard coat layer, it contains a photopolymerization initiator for accelerating the curing of this raw material. It is preferable to use a resin composition. As content of a photoinitiator, it is preferable to contain by mass ratio in the range of photoinitiator: active ray curable compound = 20: 100-0.01: 100.

  The photopolymerization initiator is not particularly limited. Specific examples of the photopolymerization initiator include alkylphenone series, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof.

  A commercial item may be used for such a photoinitiator, for example, Irgacure 184, Irgacure 907, Irgacure 651, etc. by BASF Japan Ltd. are mentioned as a preferable illustration.

(Conductive agent)
The hard coat layer may contain a conductive agent in order to impart antistatic properties. That is, the resin composition used for forming the hard coat layer (hard coat layer forming resin composition) may contain a conductive material. Preferred conductive agents include metal oxide particles or π-conjugated conductive polymers. An ionic liquid is also preferably used as the conductive compound.

(Additive)
The hard coat layer may contain a silicone-based surfactant, a fluorine-based surfactant, an anionic surfactant, and an additive such as a fluorine-siloxane graft compound, a fluorine-based compound, and an acrylic copolymer. That is, the resin composition used for forming the hard coat layer may contain the additive. Moreover, you may contain the compound in the range whose HLB value is 3-18 as an additive. Water repellency can be controlled by adjusting the type and amount of these additives.

  The HLB value is a hydrophilic-lipophilic-balance. That is, the HLB value is a value indicating the hydrophilicity or lipophilicity of the compound. The smaller the HLB value, the higher the lipophilicity, and the higher the value, the higher the hydrophilicity. The HLB value can be obtained by the following calculation formula.

HLB = 7 + 11.7Log (Mw / Mo)
In the formula, Mw represents the molecular weight of the hydrophilic group, Mo represents the molecular weight of the lipophilic group, and Mw + Mo = M (molecular weight of the compound). Specific examples of the compound having an HLB value in the range of 3 to 18 include the following compounds, but are not particularly limited thereto. In addition, () shows an HLB value.

  Examples of compounds having an HLB value in the range of 3 to 18 include Kao Corporation: Emulgen 102KG (6.3), Emulgen 103 (8.1), Emulgen 104P (9.6), and Emulgen 105 (9.7). , Emulgen 106 (10.5), Emulgen 108 (12.1), Emulgen 109P (13.6), Emulgen 120 (15.3), Emulgen 123P (16.9), Emulgen 147 (16.3), Emulgen 210P (10.7), Emulgen 220 (14.2), Emulgen 306P (9.4), Emulgen 320P (13.9), Emulgen 404 (8.8), Emulgen 408 (10.0), Emulgen 409PV ( 12.0), Emulgen 420 (13.6), Emulgen 430 (16.2), Emulgen 705 (10.5) Emulgen 707 (12.1), Emulgen 709 (13.3), Emulgen 1108 (13.5), Emulgen 1118S-70 (16.4), Emulgen 1135S-70 (17.9), Emulgen 2020G-HA (13 0.0), Emulgen 2025G (15.7), Emulgen LS-106 (12.5), Emulgen LS-110 (13.4), Emulgen LS-114 (14.0), manufactured by Nissin Chemical Industry Co., Ltd .: Surfinol 104E (4), Surfinol 104H (4), Surfinol 104A (4), Surfinol 104BC (4), Surfinol 104DPM (4), Surfinol 104PA (4), Surfinol 104PG-50 (4) , Surfinol 104S (4), Surfinol 420 (4), Finol 440 (8), Surfinol 465 (13), Surfinol 485 (17), Surfinol SE (6), manufactured by Shin-Etsu Chemical Co., Ltd .: X-22-4272 (7), X-22-6266 (8 ), KF-351 (12), KF-352 (7), KF-353 (10), KF-354L (16), KF-355A (12), KF-615A (10), KF-945 (4) , KF-618 (11), KF-6011 (12), KF-6015 (4), KF-6004 (5), and the like.

  Moreover, examples of the silicone surfactant include polyether-modified silicone, and more specifically, the KF series manufactured by Shin-Etsu Chemical Co., Ltd. and the like. Examples of the acrylic copolymer include commercially available compounds such as BYK-350 and BYK-352 manufactured by Big Chemie Japan. Examples of the fluorosurfactant include Megafac RS series manufactured by DIC Corporation, Megafac F-444 Megafac F-556, and the like. Examples of the fluorine-siloxane graft compound include a compound of a copolymer obtained by grafting polysiloxane containing siloxane and / or organosiloxane alone and / or organopolysiloxane to a fluorine-based resin. Examples of the commercially available products include ZX-022H, ZX-007C, ZX-049, ZX-047-D and the like manufactured by Fuji Kasei Kogyo Co., Ltd. Moreover, as a fluorine-type compound, Daikin Industries Ltd. OPTOOL DSX, OPTOOL DAC, etc. can be mentioned. These components are preferably added in the range of 0.005 parts by mass or more and 5 parts by mass or less with respect to the solid component in the hard coat composition.

(UV absorber)
The hard coat layer may contain an ultraviolet absorber. That is, the resin composition used for forming the hard coat layer may contain an ultraviolet absorber. When the composition of the film in the case of containing an ultraviolet absorber is composed of two or more layers and the substrate film is a cellulose ester film, it is preferable that the hard coat layer in contact with the cellulose ester film contains an ultraviolet absorber.

  As content of a ultraviolet absorber, it is preferable to contain by mass ratio in the range of ultraviolet absorber: resin which comprises a hard-coat layer = 0.01: 100-10: 100. When two or more layers are provided, the thickness of the hard coat layer in contact with the cellulose ester film is preferably in the range of 0.05 to 2 μm. Two or more layers may be formed as a simultaneous multilayer. The simultaneous multi-layer is to form a hard coat layer by applying two or more hard coat layers on a base material without going through a drying step. In order to laminate the second hard coat layer on the first hard coat layer without a drying process, the layers are stacked one after another by an extrusion coater or simultaneously by a slot die having a plurality of slits. Just do.

(solvent)
The hard coat layer may be a resin composition for forming a hard coat layer by diluting the components forming the hard coat layer with a solvent that swells or partially dissolves the cellulose ester film that is the base film. preferable. That is, it is preferable that the resin composition for forming a hard coat layer contains a good solvent for a cellulose ester film that is a base film. And it is preferable to provide the hard-coat layer by apply | coating, drying and hardening | curing the resin composition for hard-coat layer formation containing such a solvent on a base film with the following methods.

  As the solvent, ketone (methyl ethyl ketone, acetone, etc.) and / or acetate ester (methyl acetate, ethyl acetate, butyl acetate, etc.), alcohol (ethanol, methanol), propylene glycol monomethyl ether, cyclohexanone, methyl isobutyl ketone, etc. are preferable. The coating amount of the hard coat layer forming resin composition is suitably in the range of 0.1 to 40 μm as a wet film thickness, and preferably in the range of 0.5 to 30 μm. The dry film thickness is in the range of 0.01 to 20 μm, preferably in the range of 0.5 to 10 μm. More preferably, it is the range of 0.5-5 micrometers.

  As a method for applying the resin composition for forming a hard coat layer, known methods such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, and an ink jet method can be used.

(Hard coat layer forming method)
The formation method of a hard-coat layer is obtained by hardening the above resin compositions for hard-coat layer formation on a base film. Specifically, a hard coat layer is formed by applying a resin composition for forming a hard coat layer on a base film, then drying the applied layer and irradiating and curing with an active ray. More specifically, a method of forming using an optical film manufacturing apparatus as shown in FIG. Moreover, as a method of curing by irradiating active rays, for example, a UV curing treatment and the like can be mentioned. Moreover, you may heat-process as needed after the hardening process which irradiated the active rays, such as UV hardening process. The heat treatment temperature after the UV curing treatment or the like is preferably 80 ° C. or higher, more preferably 100 ° C. or higher, and further preferably 120 ° C. or higher. By performing subsequent heat treatment such as UV curing treatment at such a high temperature, a hard coat layer having excellent film strength can be obtained.

  It is preferable that the drying is performed by a high-temperature treatment in which the temperature in the decreasing rate drying section is 90 ° C. or higher. More preferably, the temperature in the decreasing rate drying section is 90 ° C. or higher and 125 ° C. or lower. By setting the temperature of the rate-decreasing drying section to a high temperature, convection occurs in the coating resin during the formation of the hard coat layer, and as a result, irregular surface roughness is likely to appear on the hard coat layer surface, and the arithmetic average It is easy to control the roughness Ra.

  In general, it is known that the drying process changes from a constant state to a gradually decreasing state when drying starts. The decreasing section is called the decreasing rate drying section. In the constant rate drying section, the amount of heat flowing in is all consumed for solvent evaporation on the coating film surface, and when the solvent on the coating film surface decreases, the evaporation surface moves from the surface to the inside and enters the decreasing rate drying section. Thereafter, the temperature of the coating film surface rises and approaches the hot air temperature, so that the temperature of the actinic radiation curable resin composition rises, the resin viscosity decreases, and the fluidity increases.

  As a light source for UV curing treatment, any light source that generates ultraviolet rays can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.

Irradiation conditions vary depending on individual lamps, irradiation of actinic rays is generally within the range of 50~1000mJ / cm ^2, preferably in the range of 50 to 300 mJ / cm ^2. In the UV curing treatment, oxygen removal (for example, replacement with an inert gas such as nitrogen purge) can be performed to prevent reaction inhibition by oxygen. The cured state of the surface can be controlled by adjusting the removal amount of the oxygen concentration. When irradiating actinic radiation, it is preferably performed while applying tension in the film transport direction, and more preferably while applying tension in the width direction. The tension to be applied is preferably 30 to 300 N / m. The method for applying the tension is not particularly limited, and the tension may be applied in the transport direction on the back roller, or the tension may be applied in the width direction or the biaxial direction by a tenter. Thereby, a film having further excellent flatness can be obtained.

(Haze)
The haze of the hard coat film is preferably in the range of 0.2 to 10% from the visibility when used in an image display device. Haze can be measured according to JIS-K7105 and JIS K7136.

(hardness)
The hard coat film has a pencil hardness, which is an index of hardness, of HB or more, more preferably H or more. If it is more than HB, it will be hard to be damaged in the process of manufacturing a polarizing plate using this hard coat film. The pencil hardness is determined by conditioning the prepared optical film at a temperature of 23 ° C. and a relative humidity of 55% for 2 hours or more, and then using a test pencil specified by JIS S6006 under a load of 500 g, It is the value which measured the functional layer in accordance with the pencil hardness evaluation method prescribed | regulated by JISK5400.

  Moreover, as a functional layer, layers other than the said hard-coat layer may be sufficient. Moreover, you may provide another layer on a hard-coat layer. Specifically, the following layers may be provided.

<Other layers>
As another layer, if it is a layer with which an optical film is equipped, it will not specifically limit. Specific examples include an antireflection layer and a conductive layer. In addition, when other layers are provided on the hard coat layer, the hard coat film has other antireflection layers, conductive layers, etc. on the film or between the hard coat layer and the base film. A layer can be provided.

  The hard coat film can be used as an antireflection film having an antireflection function for external light by coating an antireflection layer on the hard coat layer.

  The antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is composed of a low refractive index layer having a lower refractive index than the protective film as the support, or a combination of a high refractive index layer and a low refractive index layer having a higher refractive index than the protective film as the support. Preferably it is. Particularly preferably, it is an antireflection layer composed of three or more refractive index layers, and three layers having different refractive indexes from the support side are divided into medium refractive index layers (high refractive index layers having a higher refractive index than the support). Are preferably laminated in the order of a layer having a lower refractive index) / a high refractive index layer / a low refractive index layer. Alternatively, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used. As the layer structure, the following structure is conceivable, but is not limited thereto.

Cellulose ester film (base film) / hard coat layer / low refractive index layer Cellulose ester film / hard coat layer / high refractive index layer / low refractive index layer Cellulose ester film / hard coat layer / medium refractive index layer / high refractive index Layer / low refractive index layer hard coat layer / cellulose ester film / hard coat layer / low refractive index layer hard coat layer / cellulose ester film / hard coat layer / high refractive index layer / low refractive index layer hard coat layer / cellulose ester film / Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer Low refractive index layer / Hard coat layer / Cellulose ester film / Hard coat layer / Low refractive index layer

(Low refractive index layer)
The low refractive index layer preferably contains silica-based fine particles, and the refractive index is preferably in the range of 1.30 to 1.45 when measured at 23 ° C. and a wavelength of 550 nm.

  The film thickness of the low refractive index layer is preferably in the range of 5 nm to 0.5 μm, more preferably in the range of 10 nm to 0.3 μm, and in the range of 30 nm to 0.2 μm. Most preferred.

  The composition for forming a low refractive index layer preferably contains at least one kind of particles having an outer shell layer and porous or hollow inside as silica-based fine particles. In particular, the particles having the outer shell layer and porous or hollow inside are preferably hollow silica-based fine particles.

  The composition for forming a low refractive index layer may contain an organosilicon compound represented by the following general formula (OSi-1) or a hydrolyzate thereof, or a polycondensate thereof.

General formula (OSi-1): Si (OR) ₄
In the organic silicon compound represented by the general formula, R represents an alkyl group having 1 to 4 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.

  In addition, a silane coupling agent, a curing agent, a surfactant and the like may be added as necessary. Moreover, you may contain the compound which has a thermosetting and / or photocuring property which mainly contains the fluorine atom which contains a fluorine atom in 35-80 mass%, and contains a crosslinkable or polymeric functional group. Specifically, a fluorine-containing polymer or a fluorine-containing sol-gel compound is used. As the fluorine-containing polymer, for example, a hydrofluorinated monomer in addition to a hydrolyzate or dehydration condensate of a perfluoroalkyl group-containing silane compound [for example, (heptadecafluoro-1,1,2,2-tetrahydrodecyl) triethoxysilane] Examples thereof include fluorine-containing copolymers having units and cross-linking reactive units as constituent units. In addition, you may add a solvent, a silane coupling agent, a hardening | curing agent, surfactant, etc. as needed.

(High refractive index layer)
The refractive index of the high refractive index layer is preferably adjusted to a refractive index in the range of 1.4 to 2.2 by measuring at 23 ° C. and a wavelength of 550 nm. The thickness of the high refractive index layer is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm. The means for adjusting the refractive index can be achieved by adding metal oxide fine particles and the like.

  The metal oxide fine particles used preferably have a refractive index of 1.80 to 2.60, more preferably 1.85 to 2.50.

  The kind of metal oxide fine particles is not particularly limited, and Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and S A metal oxide having at least one element selected from can be used.

(Conductive layer)
In the hard coat film, a conductive layer may be formed on the hard coat layer. As the conductive layer provided, a generally well-known conductive material can be used. For example, metal oxides such as indium oxide, tin oxide, indium tin oxide, gold, silver, and palladium can be used. These can be formed as a thin film on the hard coat film by vacuum deposition, sputtering, ion plating, solution coating, or the like. Moreover, it is also possible to form a conductive layer using the organic conductive material which is the above-described π-conjugated conductive polymer.

  In particular, a conductive material that is excellent in transparency and conductivity, and that has a main component of any of indium oxide, tin oxide, and indium tin oxide, which can be obtained at a relatively low cost, can be suitably used. Although the thickness of the conductive layer varies depending on the material to be applied, it cannot be said unconditionally. However, the surface resistivity is 1000Ω or less, preferably 500Ω or less, and considering the economy, A range of 10 nm or more, preferably 20 nm or more and 80 nm or less, preferably 70 nm or less is suitable. In such a thin film, visible light interference fringes due to uneven thickness of the conductive layer are unlikely to occur.

  As described above, the present specification discloses various modes of technology, of which the main technologies are summarized below.

  One aspect of the present invention includes a step of producing a long resin film having an embossed portion along the longitudinal direction at both ends in the width direction, and a winding step of winding the resin film into a roll around a core. And the winding step has an x-axis as the integrated thickness of the resin film being wound at the position of the resin film that starts to be wound around the core, and a center position in the width direction of the resin film, A sinusoidal vibration whose area surrounded by the function f (x) with the distance from the center position in the width direction of the winding core as the y-axis and the x-axis has the same amplitude and period as the f (x) Is larger than the area surrounded by the function a (x) and the x axis, and smaller than the area surrounded by the function b (x) of the rectangular wave vibration having the same amplitude and period as the f (x) and the x axis. So that at least one of the resin film and the core is Wherein while periodically vibrated in the width direction of the resin film, a method for producing an optical film roll comprising a vibration winding step of winding the resin film to the winding core.

  According to such a configuration, it is possible to provide a method for producing an optical film roll in which the occurrence of deformation is sufficiently suppressed even when stored for a long period of time.

  This is because the vibration that changes the relative position of the resin film and the core in the vibration winding process has the effect of overlapping the embossed part in the state of the film roll wound around the resin film. This is considered to be due to the vibration that is reduced.

  Moreover, the side shape of the obtained optical film roll becomes wavy by the vibration. The sharpness of the top of the convex portion of the wave shape becomes gentler when the side surface shape is the case of the vibration at f (x) than the case of the sinusoidal vibration. Therefore, the occurrence of damage to the side surface shape of the optical film roll can also be suppressed.

  Further, in the method of manufacturing the optical film roll, the integrated thickness of the resin film being wound is large at the position of the resin film where the amplitude of the vibration in the vibration winding step starts to be wound on the core. As it becomes, it is preferable to gradually increase.

  According to such a configuration, an optical film roll in which the occurrence of deformation is further suppressed can be manufactured. This is considered to be due to the following. First, if the amplitude of vibration is large, the width of the resin film that is used by being drawn out from the optical film roll can be shortened, but the overlapping of the embossed portions can be further suppressed and the occurrence of deformation can be further suppressed. it is conceivable that. Then, as the resin film is wound around the core, the integrated thickness of the wound resin film increases and deformation is likely to occur. It is considered that the occurrence of deformation can be further suppressed by applying a vibration having a large amplitude that can further suppress the occurrence of deformation when the integrated thickness of the resin film is likely to occur. On the other hand, at the beginning of winding where deformation is unlikely to occur, it is considered that the occurrence of deformation can be sufficiently suppressed even when vibration having a small amplitude is applied. From these things, according to said structure, it is thought that generation | occurrence | production of a deformation | transformation can be suppressed efficiently according to the thickness of integration of the resin film currently wound up.

  Further, in the method for manufacturing the optical film roll, the integrated thickness of the resin film being wound is large at a position of the resin film where the period of vibration in the vibration winding process starts to be wound around the core. As it becomes, it is preferable to gradually become smaller.

  According to such a configuration, the occurrence of deformation can be further suppressed. This is considered to be due to the following. First, if the period of vibration is small, winding deviation is likely to occur, but the load on the resin film can be reduced. Then, as the resin film is wound around the core, the integrated thickness of the wound resin film increases and deformation is likely to occur. It is considered that the occurrence of deformation can be further suppressed by applying a vibration having a small period that can reduce the load on the resin film when the integrated thickness of the resin film is likely to generate such deformation. From these things, according to said structure, it is thought that generation | occurrence | production of a deformation | transformation can be suppressed efficiently according to the thickness of integration of the resin film currently wound up.

  Moreover, in the manufacturing method of the optical film roll, the winding step includes a distance between a center position in the width direction of the resin film and a center position in the width direction of the core after the vibration winding step. It is preferable to provide a step of winding the resin film around the core without changing the length.

  When the optical film roll is manufactured, the resin film is wound up to the end by the vibration winding process, and when the resin film is started to be unwound from the obtained optical film roll, the resin film can be smoothly unwound by meandering of the resin film. Although there was no case, according to the said structure, a resin film can be smoothly drawn out from the obtained optical film roll. That is, since the winding without vibration as described above is performed after the vibration winding process, it is possible to suppress the problem of unwinding that may occur immediately after the start of unwinding of the resin film. It is possible to suppress deformation of the optical film roll at the portion where the film is wound.

  Moreover, in the manufacturing method of the said optical film roll, it is preferable that the thickness of the said resin film is 10-35 micrometers.

  According to such a structure, since the resin film is thinner than the conventional resin film, the winding length of an optical film roll can be lengthened. Further, in the case of such a thinned resin film, as described above, the optical film roll is likely to be deformed, but the optical film roll is manufactured by the optical film roll manufacturing method according to one embodiment of the present invention. By doing so, an optical film roll in which the occurrence of deformation is sufficiently suppressed can be obtained.

  Moreover, in the manufacturing method of the optical film roll, the embossed part has a plurality of convex parts, and the convex part existing in the center in the width direction of the embossed part among the plurality of convex parts is the embossed part. It is preferable that it is lower than the convex part which exists in the width direction both ends of a part.

  According to such a configuration, the occurrence of deformation can be further suppressed. According to the above configuration, when winding the resin film, even if the vibration winding process is applied, the overlap due to the convex portion existing in the center in the width direction of the embossed portion becomes thick. It is thought that this is because it can be suppressed.

  Moreover, in the manufacturing method of the said optical film roll, it is preferable that the said resin film is an optical film used as a polarizing plate protective film.

  According to such a configuration, when the optical film roll is manufactured by the method for manufacturing an optical film roll according to one embodiment of the present invention, the optical film used as the polarizing plate protective film is a resin film. An optical film roll capable of sequentially feeding out and providing an optical film in which the occurrence of defects based on it is sufficiently suppressed is obtained.

  Moreover, in the manufacturing method of the said optical film roll, it is preferable that the said resin film is a phase difference film used as an optical compensation film for liquid crystal display devices.

  According to such a configuration, when a retardation film used as an optical compensation film for a liquid crystal display device is used as a resin film and an optical film roll is manufactured by the method for manufacturing an optical film roll according to one embodiment of the present invention, an optical film roll is obtained. An optical film roll capable of sequentially feeding out and providing a retardation film in which the occurrence of problems due to deformation of the film roll is sufficiently suppressed is obtained.

  Moreover, in the manufacturing method of the said optical film roll, it is preferable that the said resin film is an optical film provided with a base film and a functional layer which exists on the said base film.

  According to such a configuration, when the optical film is manufactured by the optical film roll manufacturing method according to one aspect of the present invention using the optical film as a resin film, the occurrence of defects based on deformation of the optical film roll is sufficient. Thus, an optical film roll capable of sequentially feeding and providing the optical film suppressed by the above is obtained. Moreover, since the said optical film is equipped with a base film and a functional layer at least, the deformation | transformation by dead weight tends to occur. Even if such an optical film is used as a resin film, an optical film roll in which the occurrence of deformation is sufficiently suppressed by producing an optical film roll by the method for producing an optical film roll according to one embodiment of the present invention. can get.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” or “%” represents “parts by mass” or “% by mass” unless otherwise specified.

[Example 1]
In Example 1, an optical film that can be used as a polarizing plate protective film was used as the resin film. Specifically, the following cellulose triacetate film was used.

(Preparation of silicon dioxide dispersion)
The preparation of the silicon dioxide dispersion added to the dope will be described.

  First, 10 parts by mass of silicon dioxide (Aerosil R812 manufactured by Nippon Aerosil Co., Ltd., primary particle average diameter 7 nm) and 90 parts by mass of ethanol were stirred and mixed with a dissolver for 30 minutes, and then dispersed using a Manton Gorin disperser. And a dispersion was prepared.

  Then, 88 parts by mass of methylene chloride was placed in the dissolution tank, and the dispersion prepared above was slowly added while sufficiently stirring the methylene chloride, followed by stirring and mixing with a dissolver for 30 minutes. The obtained dispersion was filtered with a fine particle dispersion diluent filter (manufactured by Advantech Toyo Co., Ltd .: polypropylene wind cartridge filter TCW-PPS-1N) to prepare a silicon dioxide dispersion.

(Preparation of dope)
Next, preparation of the dope will be described.

  First, cellulose triacetate resin (cellulose triacetate synthesized from linter cotton, substitution degree of acetyl group 2.88, Mn = 14000) as a transparent resin in a dissolution tank containing 432 parts by mass of methylene chloride and 38 parts by mass of ethanol 90 5 parts by mass of an ester compound represented by the following formula (X-1), 4 parts by mass of an ester compound represented by the following formula (X-12), Tinuvin 928 (manufactured by BASF Japan Ltd.) 3 Part by mass and 4 parts by mass of the silicon dioxide dispersion were added. And the resin component was dissolved by stirring under heating conditions. The resin solution obtained by doing so was used as Azumi Filter Paper No. 24 was filtered. Using the resin solution thus obtained as a dope, a resin film was produced as follows.

(Manufacture of optical film rolls)
The optical film roll was manufactured using the manufacturing apparatus of the resin film by a solution casting film forming method as shown in FIG. First, the dope was cast from a casting die (coat hanger die) onto an endless belt support made of stainless steel. Then, the web was dried (the solvent in the web was evaporated) until the residual solvent amount of the web cast on the endless belt support reached 100 mass, and then the web was peeled off as a film from the endless belt support.

  The peeled film was further dried at 35 ° C. and slit to a width of 1.15 m. Thereafter, the slit film was stretched 1.15 times in the width direction (TD direction) using a stretching device (tenter), and further dried at 140 ° C. Thereafter, the film was dried for 15 minutes while the film was transported by a number of rollers in a drying apparatus set to 120 ° C., and then slit to a width of 1.3 m. Then, knurling which forms an embossed part having a shape as shown in FIG. 5A and a width of 10 mm and a height of 5 μm was performed on both ends of the film with an embossing apparatus. In addition, the resin film was manufactured so that the thickness of a film might be 25 micrometers. Further, the draw ratio in the MD direction calculated from the rotational speed of the endless belt support and the operating speed of the tenter was 1.01. Moreover, the resin film obtained here is also called TAC1.

  Next, an optical film roll was manufactured by winding the obtained resin film in a roll shape around a core using a winding device. Specifically, it was manufactured as follows. The knurled film was wound on a winding core at a speed of 80 m / min, a winding initial tension of 140 N, a winding end tension of 90 N, and the nip force of the touch roller was constant at 20 N, and wound up 4000 m to prepare an optical film roll. Further, when the resin film was wound around the core, vibration winding (oscillate winding) was performed in which the core was vibrated while vibrating. Further, the vibration was performed so that the vibration was a function f (x) represented by a curve 61 shown in FIG. By doing so, the optical film roll concerning Example 1 was obtained. FIG. 9 is a graph for explaining vibrations in the vibration winding process in Examples and Comparative Examples.

[Example 2]
It is the same as that of Example 1 except having used the film (TAC3) manufactured so that thickness might be set to 40 micrometers instead of TAC1 used in Example 1 with the same composition as TAC1.

[Example 3]
Instead of TAC1 used in Example 1, it is the same as Example 1 except that a film (TAC2) having the same composition as TAC1 and having a thickness of 30 μm was used.

[Example 4]
In Example 4, a retardation film that can be used as an optical compensation film for a liquid crystal display device was used as the resin film. Specifically, the following cellulose acetate propionate film was used.

(Preparation of fine particle additive solution)
The fine particle additive solution added to the dope will be described.

  First, 11 parts by mass of fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd., average primary particle diameter of 16 nm, apparent specific gravity of 90 g / L) and 89 parts by mass of ethanol were stirred and mixed with a dissolver for 50 minutes, and then a Manton Gorin disperser. Was used for dispersion to prepare a fine particle dispersion.

  And 99 mass parts of methylene chloride was put into the dissolution tank, and after sufficiently stirring the methylene chloride, Azumi Filter Paper No. Filtered using 244. While sufficiently stirring the filtrate obtained by filtration, 11 parts by mass of the fine particle dispersion prepared above was slowly added. Further, the secondary particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution.

(Preparation of dope)
Next, preparation of the dope will be described.

  First, in a pressure dissolution tank containing 390 parts by mass of methylene chloride and 80 parts by mass of ethanol, cellulose acetate propionate (acetyl group substitution degree 1.5, propionyl group substitution degree 1, acyl group substitution degree) was used as a transparent resin. Total substitution degree 2.5) 100 parts by mass was added, and 5 parts by mass of an aromatic terminal ester compound obtained by the following production method and 5.5 parts by mass of trimethylolpropane tribenzoate were added. And the resin component was dissolved by stirring under heating conditions. The resin solution obtained by doing so was used as Azumi Filter Paper No. Filtered using 244. Next, 100 parts by mass of the resin solution thus obtained and 5 parts by mass of the fine particle additive solution are sufficiently stirred with an in-line mixer (a static in-tube mixer Hi-Mixer, SWJ manufactured by Toray Industries, Inc.). Using the obtained liquid as a dope, a resin film was produced as follows.

(Production of aromatic terminal ester compounds)
A reaction vessel was charged with 410 parts by mass of phthalic acid, 610 parts by mass of benzoic acid, 418 parts by mass of 1,3-propanediol, and 0.35 parts by mass of tetraisopropyl titanate as a catalyst. Then, while stirring in a nitrogen stream, attach a reflux condenser to reflux excess monohydric alcohol, and continue to heat at 130-250 ° C until the acid value becomes 2 or less. did. Next, the distillate was removed at 200 to 230 ° C. under reduced pressure of 400 Pa or less, and then filtered. By doing so, an aromatic terminal ester having the following properties was obtained.

Viscosity (25 ° C., mPa · s); 37000
Acid value: 0.05

(Manufacture of optical film rolls)
The optical film roll was manufactured using the manufacturing apparatus of the resin film by a solution casting film forming method as shown in FIG. First, the dope having a temperature adjusted to 35 ° C. was cast from a casting die (coat hanger die) to an endless belt support having a length of 100 m so that the casting width was 1650 mm. As the endless belt support, an endless belt support made of a stainless steel endless belt having a width of 1800 mm whose surface was polished to a mirror surface was used.

  Then, after the web cast on the endless belt support is moved for 1.5 minutes by the rotation of the endless belt support, the film is removed from the endless belt support with a peeling tension of 100 N / m using a peeling roller. As peeled off. At the time of peeling, 10 ° C. cold air was blown onto the web. Moreover, the conveyance tension | tensile_strength to a uniaxial stretching apparatus was 200 N / m.

  The peeled film was stretched 30% in the width direction (TD direction) using a uniaxial stretching apparatus using a clip tenter. In addition, heating air was sprayed on the film at the time of stretching so that the residual solvent amount of the film after stretching was 7% by mass, and the temperature of the heating air was adjusted.

  The film was dried while the film was being conveyed by a number of rollers in the drying apparatus. In addition, the temperature of the heating air in a drying apparatus was adjusted so that the residual solvent amount of the film after drying might be 0.01 mass%. Then, knurling which forms an embossed part having a shape as shown in FIG. 5A and a width of 10 mm and a height of 5 μm was performed on both ends of the film with an embossing apparatus. In addition, the resin film was manufactured so that the thickness of a film might be set to 30 micrometers. Moreover, the resin film obtained here is a phase difference film, and is called CAP here.

  Next, an optical film roll was manufactured by winding the obtained resin film in a roll shape around a core using a winding device. Specifically, it was manufactured as follows. The knurled film was wound on a winding core at a speed of 80 m / min, a winding initial tension of 165 N, a winding end tension of 105 N, and the nip force of the touch roller was constant at 24 N, and the film was wound up 4000 m to produce an optical film roll. Further, when the resin film was wound around the core, vibration winding (oscillate winding) was performed in which the core was vibrated while vibrating. Further, the vibration was performed so that the vibration was a function f (x) represented by a curve 61 shown in FIG. By doing so, the optical film roll which concerns on Example 4 was obtained.

[Example 5]
In Example 5, an optical film including a base film and a functional layer present on the base film was used as the resin film. Specifically, a hard coat film provided with a hard coat layer as a functional layer as described below was used.

(Base film)
As a base film, the cellulose triacetate film in Example 1 was used. That is, the resin film before knurling in Example 1 was used.

(Hard coat layer forming resin composition)
70 parts by mass of pentaerythritol tri / tetraacrylate (NK ester A-TMM-3L manufactured by Shin-Nakamura Chemical Co., Ltd.) as an actinic radiation curable compound, trimethylolpropane triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) 30 parts by mass of A-TMPT), 6 parts by mass of Irgacure 184 (manufactured by BASF Japan), 2 parts by mass of polyether-modified silicone oil (KF-354L, manufactured by Shin-Etsu Chemical Co., Ltd.) as an additive, and propylene glycol A resin composition was prepared by adding to a mixed solvent of 20 parts by mass of monomethyl ether, 30 parts by mass of methyl acetate and 70 parts by mass of methyl ethyl ketone and stirring. The obtained resin composition was filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a resin composition for forming a hard coat layer.

(Formation of hard coat layer)
First, the resin composition for forming a hard coat layer was applied to the surface of the base film that was not in contact with the endless belt support (A surface) during production using an extrusion coater. The film on which the resin composition for forming a hard coat layer was applied on the surface was dried by being conveyed into a drying apparatus having an apparatus internal temperature of 50 ° C. Thereafter, while purging with nitrogen so that the atmosphere had an oxygen concentration of 1% by volume or less, the application side of the dried film was irradiated with ultraviolet rays using an ultraviolet lamp. At that time, ultraviolet rays were irradiated so that the illuminance was 100 mW / cm ² and the irradiation amount was 0.2 J / cm ² . By doing so, a hard coat layer was formed. The hard coat layer was formed so that the thickness of the hard coat layer was 2.5 μm. Then, knurling which forms an embossed part having a shape as shown in FIG. 5A and a width of 10 mm and a height of 5 μm was performed on both ends of the film with an embossing apparatus. The film thus formed with the hard coat layer formed thereon is a hard coat film, and is referred to herein as HC-TAC.

  Next, an optical film roll was manufactured by winding the obtained film in a roll shape around a core using a winding device. Specifically, it was manufactured as follows. The film subjected to the knurling process was wound on a winding core at a speed of 30 m / min, a winding initial tension of 250 N and a winding end tension of 150 N, and wound up to 4000 m to prepare an optical film roll. Here, no touch roller was used. Further, when the resin film was wound around the core, vibration winding (oscillate winding) was performed in which the core was vibrated while vibrating. Further, the vibration was performed so that the vibration was a function f (x) represented by a curve 61 shown in FIG. By doing so, the optical film roll which concerns on Example 5 was obtained.

[Example 6]
Example 1 except that when the resin film is wound around the core, the amplitude of vibration in the oscillating winding gradually increases as the integrated thickness of the resin film wound around the core increases. It is the same. Specifically, the amplitude of vibration was 5 mm at the beginning of winding and gradually increased, and the amplitude of vibration was 7 mm at the end of winding.

[Example 7]
Example 1 except that when the resin film is wound around the winding core, the period of vibration in the oscillating winding gradually decreases as the integrated thickness of the resin film wound around the winding core increases. It is the same. Specifically, at the beginning of winding, the vibration period was 160 mm and gradually decreased, and at the end of winding, the vibration period was set to 100 mm.

[Example 8]
Instead of TAC1 used in Example 1, it was the same as Example 1 except that a film (TAC4) in which an embossed part having a shape as shown in FIG. is there.

[Comparative Example 1]
When winding the resin film around the core, it is the same as in Example 1 except that the center distance between the resin film and the core is not changed. That is, it is the same as in Example 1 except that the resin film is wound around the core without changing the distance between the center position in the width direction of the resin film and the center position in the width direction of the core.

[Comparative Example 2]
Example 1 is the same as Example 1 except that the vibration at the time of oscillating winding is such that the vibration becomes the function a (x) represented by the curve 62 shown in FIG. That is, the first embodiment is different from the first embodiment except that the vibration at the time of oscillating winding is a vibration that is a function of a sinusoidal vibration a (x) having the same amplitude and period as f (x). It is the same.

[Comparative Example 3]
It is the same as that of the comparative example 1 except having used TAC3 instead of TAC1.

[Comparative Example 4]
It is the same as that of the comparative example 2 except having used TAC3 instead of TAC1.

[Comparative Example 5]
It is the same as that of the comparative example 2 except having used TAC2 instead of TAC1.

[Comparative Example 6]
When winding the resin film around the core, it is the same as in Example 1 except that the center distance between the resin film and the core is not changed. That is, it is the same as Example 4 except that the resin film is wound around the core without changing the distance between the center position in the width direction of the resin film and the center position in the width direction of the core.

[Comparative Example 7]
Example 1 is the same as Example 1 except that the vibration at the time of oscillating winding is such that the vibration becomes the function a (x) represented by the curve 62 shown in FIG. That is, the fourth embodiment is different from the fourth embodiment except that the vibration at the time of oscillating winding is such that the vibration is a function of sinusoidal vibration a (x) having the same amplitude and period as f (x). It is the same.

[Comparative Example 8]
When winding the resin film around the core, it is the same as in Example 1 except that the center distance between the resin film and the core is not changed. That is, it is the same as Example 5 except that the resin film is wound around the core without changing the distance between the center position in the width direction of the resin film and the center position in the width direction of the core.

[Comparative Example 9]
Example 1 is the same as Example 1 except that the vibration at the time of oscillating winding is such that the vibration becomes the function a (x) represented by the curve 62 shown in FIG. That is, the fifth embodiment is different from the fifth embodiment except that the vibration at the time of oscillating winding is such that the vibration is a function of sinusoidal vibration a (x) having the same amplitude and period as f (x). It is the same.

  The conditions in Examples 1-8 and Comparative Examples 1-9 are summarized in Table 1 below.

  The following evaluation was performed on each optical film roll obtained as described above, and the results are shown in Table 2.

[Film roll durability test evaluation]
Each optical film roll obtained as described above was subjected to a durability test assuming long-term storage. Specifically, each optical film roll obtained as described above was stored for 10 days in a thermostatic bath at 50 ° C. and a relative humidity of 80% while being wrapped in an aluminum moisture-proof sheet. After storage for 10 days, the aluminum moisture-proof sheet was removed. And the external appearance of the optical film roll was evaluated. As a result, the area of the concave deformation such that the width direction center portion of the optical film roll is recessed downward, and as a result, the width deformation center portion of the optical film roll is recessed downward. If the area is 5% or less with respect to the entire surface of the film roll, it is evaluated as “◎”, and if it exceeds 5% and 20% or less, it is evaluated as “◯” and exceeds 20% and exceeds 50%. If it was less than%, it was evaluated as “Δ”, and if it was 50% or more, it was evaluated as “x”.

[Evaluation in liquid crystal display devices (display characteristics)]
Next, the display characteristics of the liquid crystal display device to which the film fed out from each optical film roll obtained as described above was applied were evaluated.

  First, a liquid crystal display device including a polarizing plate as shown in FIG. 10 was manufactured as follows. In addition, FIG. 10 is a schematic diagram illustrating an outline of a configuration of a polarizing plate provided in a liquid crystal display device used for evaluation in Examples and Comparative Examples.

  Examples of the polarizing plate 101 include a polarizing plate including a hard coat film 102, a polarizing film 105, a retardation film 106, and an adhesive layer 107 for bonding to a liquid crystal layer in this order from the viewing side. . The hard coat film 102 is a film in which a hard coat layer 103 and a base film 104 are laminated. The hard coat film 102 is bonded to the polarizing film 105 on the base film 104 side. The polarizing plate 101 may be an optical film (polarizing plate protective film) that does not include the hard coat layer 103 instead of the hard coat film 102.

  In this evaluation, when the film drawn out from each optical film roll was a polarizing plate protective film or a hard coat film, it was arranged on the viewing side. Moreover, when the film drawn | fed out from each optical film roll is retardation film, it has arrange | positioned to the liquid crystal layer side. Specifically, the films fed out from the optical film rolls according to Examples 1 to 3, Examples 5 to 8, Comparative Examples 1 to 5, and Comparative Examples 8 and 9 are replaced with the hard coat film 102 in FIG. Applied to. Moreover, the film drawn | fed out from the optical film roll which concerns on Example 4 and Comparative Examples 6 and 7 was applied instead of the retardation film 106 in FIG. Further, when this example and the comparative example are not applied, a polarizing plate protective film (KC4UY manufactured by Konica Minolta Co., Ltd.) is used for the hard coat film 102 in FIG. 10, and the thickness of the retardation film 106 is 40 μm. No. retardation film (KC4DR-1 manufactured by Konica Minolta Co., Ltd.) was used. In addition, the film used from the film roll after performing the durability test of the said film roll was used for the film.

  More specifically, it was produced as follows.

(A) Production of Polarizing Film What was impregnated with 10 parts by mass of glycerin and 170 parts by mass of water in 100 parts by mass of polyvinyl alcohol (hereinafter abbreviated as PVA) having a saponification degree of 99.95 mol% and a polymerization degree of 2400 After melt-kneading and defoaming, it was melt extruded from a T die onto a metal roller to form a film. Then, it dried and heat-processed and obtained the PVA film.

  The obtained PVA film had an average thickness of 25 μm, a moisture content of 4.4%, and a film width of 3 m. Next, the obtained PVA film was continuously processed in the order of preliminary swelling, dyeing, uniaxial stretching by a wet method, fixing treatment, drying, and heat treatment to prepare a polarizing film. That is, the PVA film was preliminarily swollen in water at a temperature of 30 ° C. for 30 seconds, and immersed in an aqueous solution having an iodine concentration of 0.4 g / liter and a potassium iodide concentration of 40 g / liter at a temperature of 35 ° C. for 3 minutes. Subsequently, the film was uniaxially stretched 6 times in a 50% aqueous solution with a boric acid concentration of 4% under the condition that the tension applied to the film was 700 N / m, and the potassium iodide concentration was 40 g / liter and the boric acid concentration was 40 g / liter. Then, it was immersed in an aqueous solution having a zinc chloride concentration of 10 g / liter and a temperature of 30 ° C. for 5 minutes for fixing. Thereafter, the PVA film was taken out, dried with hot air at a temperature of 40 ° C., and further heat-treated at a temperature of 100 ° C. for 5 minutes. By doing so, a polarizing film was obtained. The obtained polarizing film had an average thickness of 13 μm, a polarizing performance of a transmittance of 43.0%, a polarization degree of 99.5%, and a dichroic ratio of 40.1.

(B) Production of Polarizing Plate According to the following steps 1 to 4, a polarizing plate protective film or hard coat film 102, a polarizing film 105, and a retardation film 106 were bonded together to produce a polarizing plate.

  Process 1: The above-mentioned polarizing film was immersed in the storage tank of the polyvinyl alcohol adhesive agent solution of 2 mass% of solid content for 1-2 seconds.

  Process 2: The alkali treatment was implemented on the polarizing plate protective film or hard coat film, and retardation film on the following conditions. Next, in Step 1, the polarizing film was immersed in the polyvinyl alcohol adhesive solution. The excess adhesive adhering to the immersed polarizing film is lightly removed, and a polarizing plate protective film or hard coat film and a retardation film having a thickness of 40 μm are sandwiched between the polarizing films as shown in FIG. Arranged.

(Alkali treatment)
Saponification step 2.5 mol / L-KOH 50 ° C. 120 seconds Water washing step Water 30 ° C. 60 seconds Neutralization step 10 parts HCl 30 ° C. 45 seconds Water washing step Water 30 ° C. 60 seconds After saponification treatment, water washing, neutralization, water washing in this order And then dried at 100 ° C.

Step 3: The laminate was bonded at a speed of about 2 m / min at a pressure of ^{20 to} 30 N / cm ² with two rotating rollers. At this time, care was taken to prevent bubbles from entering.

  Step 4: The sample produced in Step 3 was dried in a dryer at a temperature of 100 ° C. for 5 minutes.

  Thereafter, the pressure-sensitive adhesive layer 107 was provided on the obtained laminate as follows.

(Adhesive layer)
A commercially available acrylic pressure-sensitive adhesive was applied to the retardation film 106 of the polarizing plate so that the thickness after drying was 25 μm, and dried in an oven at 110 ° C. for 5 minutes to form an adhesive layer 107. Thereafter, a peelable protective film was attached to the adhesive layer 107.

<Production of liquid crystal display device>
(Durability test evaluation)
A protective film was peeled off from the produced polarizing plate, and the polarizing plate was attached to the liquid crystal layer of the liquid crystal display device to produce a liquid crystal display device. Specifically, it was as follows.

(Liquid crystal display device)
Of the two pairs of polarizing plates installed on the VA mode type liquid crystal display device (BRAVIA KDL-52W5 manufactured by SONY) with the liquid crystal layer sandwiched therebetween, the polarizing plate on one side on the viewer side is peeled off, and the produced polarizing plate 101 is removed. The adhesive layer 107 and the liquid crystal layer (liquid crystal cell glass) were bonded so that the hard coat layer was on the viewing side. A liquid crystal display device was manufactured by arranging the transmission axis of the polarizing plate on the observer side and the transmission axis of the polarizing plate on the backlight side to be orthogonal to each other.

  The following evaluation was performed using the obtained liquid crystal display device.

(Uneven evaluation)
A black image was displayed on the obtained liquid crystal display device. Next, the displayed black image was visually observed from the front. As a result, when the unevenness considered to be caused by deformation could not be confirmed at all, it was evaluated as “◎”. Moreover, when the nonuniformity considered to be attributable to deformation could be confirmed slightly, it was evaluated as “◯”. Moreover, when the nonuniformity considered to be originated from a fine deformation | transformation can be confirmed, it evaluated as "(triangle | delta)". Moreover, when the nonuniformity considered to be caused by deformation could be clearly confirmed, it was evaluated as “×”.

(Flatness)
The obtained liquid crystal display device was placed on a desk having a height of 80 cm from the floor. Two sets of daylight direct fluorescent lamps (FLR40S • D / MX, manufactured by Panasonic Corporation, 40W) were placed on the ceiling 3 m from the floor, and 10 sets were arranged at 1.5 m intervals. At that time, when the evaluator is in front of the image display unit of the liquid crystal display device, the liquid crystal display device and the fluorescent lamp are arranged so that the fluorescent lamp comes to the ceiling from behind the evaluator's head toward the rear. Then, the following criteria were used to evaluate the shape of the fluorescent lamp reflected in the image forming unit of the liquid crystal display device. As a result, if the fluorescent lamp looks straight, evaluate as `` ◎ '', and if you can see where the fluorescent lamp looks slightly bent, evaluate as `` ○ '' and the fluorescent lamp is slightly bent over the whole When it seemed to be present, it was evaluated as “Δ”, and when the fluorescent lamp seemed to swell largely throughout, it was evaluated as “x”.

  The above evaluation results are shown in Table 2.

  As can be seen from Tables 1 and 2, when winding the resin film, when the core is vibrated to satisfy the above f (x) (Examples 1 to 8), when such vibration is not performed ( It can be seen that the film rolls obtained are less deformed than Comparative Examples 1-9). Moreover, also when the film which concerns on Examples 1-8 is used for a liquid crystal display device, it turns out that generation | occurrence | production of the problem by deformation | transformation of a film roll is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, even if it preserve | saves for a long period of time, the manufacturing method of the optical film roll by which generation | occurrence | production of a deformation | transformation was fully suppressed is provided.

DESCRIPTION OF SYMBOLS 1 Winding core 2 Resin film 3 Guide roller 4 Vibration control apparatus 5 Embossing part 6 Touch roller 7 Film roll 10 Winding apparatus 11, 21 Resin film manufacturing apparatus 12 Endless belt support 13, 23 Casting die 14, 27 Peeling roller 15, 30 Stretching device 17 Drying device 18, 31, 46 Embossed portion forming device 19 Dope 22 First cooling roller 24 Surface correction touch roller 25 Second cooling roller 26 Third cooling roller 29 Conveying roller 41 Optical film manufacturing device 42 winding Dispensing device 43 Coating device 44 Drying device 45 Curing device 101 Polarizing plate 102 Hard coat film 103 Hard coat layer 104 Base film 105 Polarizing film 106 Retardation film 107 Adhesive layer

Claims (9)

A step of producing a long resin film having an embossed portion along the longitudinal direction at both ends in the width direction;
A winding step of winding the resin film into a roll around a core;
In the winding step, the integrated thickness of the resin film being wound at the position of the resin film that starts to be wound around the core is defined as the x-axis, the center position in the width direction of the resin film, and the winding A function f (x) having the distance from the center position in the width direction of the core as a y-axis and the area surrounded by the x-axis is a function a of sinusoidal vibration having the same amplitude and cycle as the f (x). It is larger than the area surrounded by (x) and the x-axis and smaller than the area surrounded by the function b (x) of the rectangular wave vibration having the same amplitude and period as the f (x) and the x-axis. A vibration winding step of winding the resin film around the core while periodically vibrating at least one of the resin film and the core in the width direction of the resin film ;
The amplitude of f (x) The production method of the optical film roll, wherein a width less der Rukoto of the embossed portion.   The amplitude of the vibration in the vibration winding step gradually increases as the integrated thickness of the resin film wound up at the position of the resin film that starts to be wound around the core increases. The manufacturing method of the optical film roll of description.   The cycle of the vibration in the vibration winding step gradually decreases as the integrated thickness of the resin film wound up at the position of the resin film that starts to be wound around the core increases. The manufacturing method of the optical film roll of Claim 2.   The winding step, after the vibration winding step, without changing the distance between the center position in the width direction of the resin film and the center position in the width direction of the winding core, the resin film The manufacturing method of the optical film roll of any one of Claims 1-3 provided with the process wound up on a winding core.   The thickness of the said resin film is 10-35 micrometers, The manufacturing method of the optical film roll of any one of Claims 1-4. The embossed portion has a plurality of convex portions,
The convex part which exists in the width direction center part of the said embossed part among these convex parts is lower than the convex part which exists in the width direction both ends of the said embossed part. The manufacturing method of the optical film roll of description.   The method for producing an optical film roll according to claim 1, wherein the resin film is an optical film used as a polarizing plate protective film.   The method for producing an optical film roll according to claim 1, wherein the resin film is a retardation film used as an optical compensation film for a liquid crystal display device.   The method for producing an optical film roll according to claim 1, wherein the resin film is an optical film including a base film and a functional layer present on the base film.

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