Web processing device and method for manufacturing multilayer film

Abstract

To provide a skew adjustment device that can effectively suppress skew of long web in the transport direction.SOLUTION: The skew adjustment device adjusts the skew of long web in the transport direction in a transport path, and includes: a floating transport device; and a transport position sensor installed downstream of the floating transport device. The floating transport device extends from one end DS to the other end OS in the width direction of the web in the transport path and includes a transport curved surface that supports the web in a non-contact manner. The floating transport device is provided so as for the transport curved surface to be lapped by the transport path. The floating transport device includes a path length adjustment mechanism that can adjust so as for the path length LDS of the transport path at the end DS and the path length LOS of the transport path at the end OS to be relatively different.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a skew adjustment device for adjusting the skewness of a long web being conveyed, a web processing device for processing a web, and a manufacturing method for producing a multilayer film, which is one form of a web. [Background technology]

[0002] When processing long webs such as films, the webs are continuously transported from upstream to downstream along a transport path, and various processing is carried out by processing equipment installed along the transport path. Generally, the transport of long webs is carried out by supporting the webs on the circumferential surfaces of a number of rotatable rollers, applying force to the webs to move along their longitudinal direction, and moving the webs in the longitudinal direction.

[0003] When a long web is moved by applying force along its longitudinal direction, theoretically the web should not move in its width direction along the transport path. However, in actual operation, the web's position in the width direction along the transport path may shift due to various factors. Since such movement in the width direction is undesirable when processing the web, methods for correcting such movement have been proposed in the past (for example, Patent Documents 1-3). By employing the correction methods known in the prior art such as Patent Documents 1-3, the web's meandering, i.e., fluctuations in the web's position in the width direction caused by low accuracy in the direction of web transport, can be easily corrected. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-071834 [Patent Document 2] Japanese Patent Publication No. 2018-162121 [Patent Document 3] Japanese Patent Publication No. 2020-063150 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] One factor causing web movement in the width direction of the transport path is deformation of the web due to processing. In particular, if the web is a diagonally stretched film and subjected to a stress-relieving process, the film deforms due to stress relief, causing the transport direction of the film to become oblique in the transport path downstream from the processing point. This width direction movement of the web caused by such oblique movement cannot be adequately corrected by known methods for correcting movement.

[0006] When a web is skewed in this way, it is extremely difficult to create a transport path that curves along the skewed web due to the equipment configuration. Therefore, a method for adjusting the skew can be used to transport skewed webs along the same transport path as non-skewed webs, enabling efficient web processing.

[0007] Accordingly, the object of the present invention is to provide a skew adjustment device that can effectively suppress skew in the transport direction of a long web; a web processing device that can process a web while effectively suppressing skew; and a method for manufacturing a multilayer film that can produce a multilayer film, which is one form of a web, while effectively suppressing skew. [Means for solving the problem]

[0008] As a result of investigations aimed at solving the above-mentioned problems, the inventors of the present invention found that the above problems could be solved by employing a specific mechanism utilizing a levitation transport device, and thus completed the present invention. In other words, the present invention provides the following:

[0009] [1] A diagonal adjustment device for adjusting the diagonal direction of a long web in the transport path, The aforementioned diagonal adjustment device is Floating transport device, and A transport position sensor located downstream of the aforementioned levitation transport device. Equipped with, The levitation conveying device extends from one end DS in the width direction of the web of the conveying path to the other end OS, and has a conveying curved surface that supports the web without contact. The levitation conveying device is provided such that the conveying curved surface is wrapped by the conveying path, The floating conveying device has a conveying path length L at the end DS. DS , and the path length L of the transport path at the end OS OS It is equipped with a path length adjustment mechanism that can adjust these to be of relatively different lengths, The transport position sensor is a sensor that detects the transport position in the width direction of the web, The aforementioned path length adjustment mechanism adjusts the path length L DS and the path length L OS When the transport position sensor detects the slanting, which is tilted towards the end DS side, the path length L OS The path length L is adjusted so that it becomes relatively longer, and when the transport position sensor detects the slanting, which is tilted towards the end OS side, the path length L is adjusted. DS It is a mechanism that adjusts so that it becomes relatively longer. Diagonal adjustment device. [2] The path length adjustment mechanism is a mechanism that adjusts the amount of displacement of the conveying curved surface in the direction of the wrap axis in the direction of the wrap angle, As the amount of displacement becomes relatively larger at the end OS, the path length L OS As the relative length increases, the amount of displacement becomes relatively larger at the end DS, resulting in the path length L DS The diagonal adjustment device described in [1], wherein the length is relatively longer. [3] The levitation conveying device according to [1] or [2], wherein the levitation conveying device has a surface of a porous material having a large number of holes as the conveying curved surface, and is configured to be able to eject gas from the holes. [4] A web processing apparatus that transports a long web along a transport path and subjects the web along the transport path to a relaxation process that causes it to contract in an oblique direction, A relaxation device that performs the relaxation process and is located on the conveyance path, and the skew adjustment device according to any one of [1] to [3] A web processing apparatus comprising the same 〔5〕 The web processing apparatus according to 〔4〕, wherein the skew adjustment device is located upstream or downstream of the relaxation device or inside the relaxation device 〔6〕 A method for manufacturing a multilayer film including a diagonally stretched base material and a coating layer provided on the surface thereof, wherein the manufacturing method includes a step of applying a coating layer forming material on the surface of the diagonally stretched base material to form a coating film of the coating layer forming material, a step of subjecting the coating film to a curing treatment in a conveyance path to form a coating layer, and a skew adjustment step of adjusting the skew in the conveyance direction of the conveyed object in the conveyance path by the skew adjustment device according to any one of [1] to [3] A method for manufacturing a multilayer film including the same

Advantages of the Invention

[0010] According to the present invention, there are provided: a skew adjustment device capable of effectively suppressing the skew in the conveyance direction of a long web; a web processing device capable of processing a web while effectively suppressing the skew; and a method for manufacturing a multilayer film, which is one aspect of the web, capable of manufacturing the multilayer film while effectively suppressing the skew

Brief Description of the Drawings

[0011] [Figure 1] FIG. 1 is a top view schematically showing an example of the skew generated when a relaxation process is performed on a diagonally stretched long film [Figure 2] FIG. 2 is a side view showing an example of the skew adjustment device of the present invention [Figure 3] FIG. 3 is a perspective view showing an example of the skew adjustment device of the present invention [Figure 4]Figure 4 is a schematic front view showing an example of the levitation transport device and support device and their adjustments shown in Figures 2 and 3. [Figure 5] Figure 5 is a schematic top view showing an example of adjusting the web's skew using the skew adjustment device shown in Figures 2 to 4. [Modes for carrying out the invention]

[0012] The present invention will be described in detail below with reference to embodiments and examples, but the present invention is not limited to the embodiments and examples shown below, and may be implemented with modifications as appropriate without departing from the scope of the claims and equivalents of the present invention.

[0013] In this application, the orientation of the components of the member for carrying out the method of the present invention is "parallel" and may include an error within a range that does not significantly impair the effects of the present invention (for example, ±5°).

[0014] In this application, a "long" web refers to a web having a length of five times or more its width, preferably ten times or more, and specifically, a web of a length that can be rolled up for storage or transport. There is no particular upper limit to the ratio of length to width of the web, but it may be, for example, 100,000 times or less.

[0015] In this application, for the sake of explanation, one end of the web in the width direction is defined as "end DS" and the other end as "end OS". In actual implementation, there is no specific requirement to designate one end as the other, and these can be determined arbitrarily. In the following explanation, the left end of Figure 1 (the left side when observing the web from the upstream to the downstream side when the web is transported horizontally) will be referred to as end DS, and the right end of the Figure will be referred to as end OS.

[0016] [Diagonal] The diagonal adjustment device of the present invention is a device for adjusting the diagonal direction of a long web in the transport path. Web diagonal refers to the phenomenon in which, downstream from a certain point in the transport path, the web moves in a non-parallel direction that is tilted to one side in the web width direction relative to the transport path upstream.

[0017] Web skew typically occurs when a web is subjected to a relaxation treatment that causes diagonal shrinkage. More specifically, a typical example is a diagonally stretched film, where skew occurs when the film is subjected to a treatment that relieves the stress caused by stretching, such as heat treatment or heating treatment.

[0018] An example of skew caused by stress relaxation in a diagonally stretched film will be explained with reference to Figure 1. Figure 1 is a schematic top view showing an example of skew that occurs when a relaxation treatment is applied to a long, diagonally stretched film.

[0019] In the example in Figure 1, the elongated film 11 is a film stretched in the direction of arrow A11, and as a result has an orientation axis in the direction of arrow A11. In this example, the film 11 is transported along the horizontal direction, arrow A1, and guided to the heat treatment device 112. When the film 11 is heat-treated in the heat treatment device 112, the stress generated within the film 11 due to stretching is relieved, and as a result, the film 11 shrinks in the direction of arrow A11. Therefore, the film 12 obtained as a result of the heat treatment has an orientation axis in the direction of arrow A12, and the dimension of the film 12 along arrow A12 is shorter than the dimension of the film 11 along arrow A11.

[0020] As a result of this dimensional change, the film 12 becomes oblique, starting from the position treated by the heat treatment device 112. That is, as a result of the deformation caused by the heat treatment, the film 12 moves in the direction of arrow A12, which is a direction nonparallel to the direction of arrow A11. In the example in Figure 1, the orientation of the film 11 is such that the OS end is tilted downstream and the DS end is tilted upstream. In the case of such a film, the obliqueness generally occurs in the direction tilted toward the DS end. Such web obliqueness is more difficult to correct than web meandering, which could be corrected by conventional correction methods.

[0021] [Skewing Adjustment Device: Overview] The diagonal adjustment device of the present invention comprises a levitation conveying device and a conveying position sensor provided downstream of the levitation conveying device.

[0022] Figures 2 and 3 are a side view and a perspective view showing an example of the diagonal adjustment device of the present invention. In Figures 2 and 3, the diagonal adjustment device 100 comprises a levitation conveying device 120 and a conveying position sensor 181 provided downstream thereof. The diagonal adjustment device 100 further comprises, as optional components, an upstream support roller 131 and a downstream support roller 132 that support the web 12 on the upstream and downstream sides of the levitation conveying device 120, and a support roller 133 that supports the web 12 opposite the conveying position sensor 181. In the diagonal adjustment device 100, the levitation conveying device 120 is supported by a support device 140. For convenience of illustration, some components are not shown in Figure 3, but are shown only in Figure 2.

[0023] In this application, the transport position sensor is a sensor that detects the transport position in the width direction of the web. The position of the transport position sensor in the width direction of the web is not particularly limited, but in the usual case, the position in the width direction of the web is easiest to detect at the width direction end of the web, so it is preferable to install the transport position sensor at a position that can detect the width direction end of the web at the end DS, end OS, or both.

[0024] In the example shown in Figures 2 and 3, the transport position sensor 181 is a sensor that senses the position of the widthwise end of the web 12 as it travels on the support roller 133. Specifically, the transport position sensor 181 can be configured with a camera that observes in the direction of arrow A181, and an analysis device (not shown) that analyzes the image acquired by the camera to determine the widthwise position of the end of the web 12. With such a transport position sensor 181, it is possible to detect whether the transport position of the web 12 has shifted from a predetermined reference position toward the end DS (the far end in the drawing in Figures 2 and 3) or the end OS (the near end in the drawing in Figures 2 and 3), and the amount of that displacement.

[0025] In the present invention, the levitation conveying device extends from one end DS to the other end OS in the width direction of the web of the conveying path and has a conveying surface that supports the web without contact. The levitation conveying device is provided such that its conveying surface is wrapped by the conveying path. In the example of Figures 2 and 3, the levitation conveying device 120 extends from end DS to end OS of the web 12. The conveying surface 121 of the levitation conveying device 120 has a surface made of a porous material having a large number of holes (not shown). The levitation conveying device 120 is configured to be able to eject gas from these holes, thereby allowing the conveying surface 121 to support the web 12 without contact.

[0026] As an example of a levitation conveying device, one in which the conveying curved surface is formed of a porous material is preferably used. Examples of porous materials include porous carbon, porous alumina, porous ceramics, and porous metal sintered materials. When a levitation conveying device has a conveying surface formed of a porous material, if a compressed air device is connected to the levitation conveying device and gas is pumped into the levitation conveying device, the gas is ejected from the pores on the surface of the porous material on the conveying surface to the outside of the conveying surface, and the conveying surface supports the web without contact.

[0027] When the transport surface is formed from a porous material, numerous minute holes can be easily created on the transport surface. Therefore, compared to materials where it is relatively difficult to create minute holes such as slit nozzles or punched holes, it becomes possible to levitate the film by pressurizing the gas at a low flow rate and with low pulsation. Consequently, it becomes easy to maintain a stable levitation state.

[0028] The average pore diameter on the conveying curved surface is preferably 0.1 μm or more, more preferably 0.5 μm or more, preferably 30 μm or less, and more preferably 3.0 μm or less. If the pore diameter is too large, some pores may become blocked, causing gas leakage from other pores. However, if the pore diameter is below the upper limit, the pressure loss within the porous material is large, so even if some pores become blocked, gas leakage can be prevented.

[0029] A levitation conveying device can levitate a web by applying an upward force with gas to a web that is biased downward by gravity and / or tension, thereby supporting the web without contact. However, the levitation conveying device is not limited to this, and as shown in the examples in Figures 2 and 3, for example, it can also apply a downward force with gas from the levitation conveying device to a web that is biased upward by tension, thereby supporting the film in a non-contact state below the levitation conveying device.

[0030] The conveying surface 121 of the levitation conveying device 120 is a partially cylindrical curved surface. By having a conveying surface that is a columnar surface such as a curved surface having the shape of a cylindrical or elliptical portion of a cylinder, the conveying surface can be made to be wrapped by the conveying path at a certain wrap angle. The linear direction on the columnar surface can be parallel to the web surface on the web conveying path that wraps the conveying surface. In this application, this axial direction is called the wrap axis direction.

[0031] In the examples of FIGS. 2 to 3, the conveying curved surface 121 of the levitation conveying device 120 is wrapped at a wrap angle θw by a conveying path defined by the web 12. From the viewpoint of achieving smooth levitation conveyance and adjustment of the conveyance path length, the wrap angle θw can preferably be an angle of 180° or less. The wrap axis direction of the levitation conveying device 120 is indicated by a line 120AX that is the axis of the conveying curved surface. In the examples of FIGS. 2 to 3, only one levitation conveying device 120 is provided as the levitation conveying device, but the present invention is not limited to this, and a plurality of levitation conveying devices may be provided in parallel. In that case, it is preferable that the total wrap angle of the plurality of levitation conveying devices is within the range described above.

[0032] In the present invention, the levitation conveying device adjusts the path length L of the conveying path at the end DS DS , and the path length L of the conveying path at the end OS OS to be relatively different lengths, and includes a path length adjustment mechanism.

[0033] The path length L PS and the path length L OS The relative difference between can be specifically grasped by comparing the path length on the end DS side and the path length on the end OS side of the portion of the conveying path whose length varies by the adjustment by the levitation conveying device. In the examples of FIGS. 2 to 3, by comparing the length of the partial conveying path from the wrap end position P131 of the upstream support roller 131 to the wrap start position P132 of the downstream support roller 132 on the end DS side and the end OS side, the path length L PS and the path length L OS The relative difference between can be grasped.

[0034] The path length adjustment mechanism can be constituted by the levitation conveying device itself or a support device that supports the levitation conveying device. In the examples of FIGS. 2 to 3, the path length adjustment mechanism is constituted by a support device 140 that supports the levitation conveying device 120. The support device 140 is a device that supports the levitation conveying device 120 in a state where the position and angle of the levitation conveying device 120 in the oblique adjustment device 100 can be adjusted to various states.

[0035] By operating the support device 140 to displace the orientation of the lap axis 120AX of the transport curved surface 121, the path length L PS and path length L OS The relative differences can be adjusted. The displacement in the direction of the lap axis 120AX can be considered as a displacement in the lap angle direction. The lap angle direction here refers to the direction that bisects the lap angle or a direction close to it, and in Figures 2 and 3, the direction that bisects the lap angle is indicated by arrow A121. The lap angle direction at the lap angle θw is centered on the direction that bisects the lap angle, with one of the upstream angle direction and the downstream angle direction being positive and the other being negative, preferably in the range of greater than -(θw / 2) and less than (θw / 2), more preferably in the range of greater than -(θw / 4) and less than (θw / 4), and even more preferably in the range of greater than -(θw / 8) and less than (θw / 8).

[0036] By adjusting the displacement of the direction of the lap axis in the direction of the lap angle so that it is relatively larger at the end OS, the path length L can be extended. OS The path length L is adjusted so that it becomes relatively longer and relatively larger at the end DS. DS The relative length increases. A specific example of such adjustment will be explained with reference to Figure 4. Figure 4 is a schematic front view showing an example of the levitation conveying device and support device and their adjustments shown in Figures 2 and 3.

[0037] Figure 4 shows the levitation conveying device 120 and support device 140 shown in Figures 2 and 3, as observed from the upstream side. The left side of the drawing corresponds to the end DS side, and the right side corresponds to the end OS side. In this example, the support device 140 is rotated in the direction of arrow A140, with the central position 120C of the levitation conveying device 120 as the center. Due to this rotation, the levitation conveying device 120 is displaced to the position shown by the dashed line, with the lap axis direction changing from the direction shown by line 120AX to the direction shown by line 129AX. As a result, the amount of displacement of the lap axis on the end OS side in the lap angle direction becomes relatively larger, and the amount of displacement of the lap axis on the end DS side in the lap angle direction becomes relatively smaller.

[0038] Such adjustment of the path length can be achieved by using a levitation conveying device as a member that tilts the lap axis. If, in the configuration shown in Figures 2 to 4, a support device that comes into contact with the web surface, such as a roller, is provided instead of the levitation conveying device to tilt the lap axis in this way, friction between the web and the surface of the support device will inevitably occur. This will cause problems such as the web traversing on the support device, leading to derailment of the web, or scratches on the web surface, making it impossible to achieve adjustment of the path length.

[0039] The path length adjustment mechanism in the present invention is a path length L DS and path length L OS The adjustment is made in response to the skew detected by the transport position sensor. Such adjustments corresponding to information detected by the transport position sensor can be achieved, for example, by providing an analysis device that determines the widthwise position of the web based on information such as images acquired by the transport position sensor, and a control device that operates the path length adjustment mechanism in response to the widthwise position determined by the analysis device, and operating these devices. Alternatively, instead of such a control device, such adjustments can also be achieved by having an operator manually operate the path length adjustment mechanism based on the widthwise position determined by the analysis device.

[0040] The path length adjustment mechanism adjusts the path length L when it detects slanting towards the end DS side. OS The process is carried out so that the relative length is increased, and when a slanted slope that tilts toward the end OS is detected, the path length L DS This adjustment is performed so that the relative length becomes longer. This adjustment will be explained with reference to Figure 5. Figure 5 is a schematic top view showing an example of adjusting the web's skew using the skew adjustment device shown in Figures 2 to 4.

[0041] In Figure 5, the web 12 is obliquely moving toward the end DS side, thereby moving in the direction of arrow A51. The obliquely moving web 12 is transported downstream (upper side of the drawing in Figure 5) through a levitation transport device 120, a transport position sensor (not shown in Figure 5), and other components of the skew adjustment device 100. Without any adjustment for skew, the web 12 moves downstream of the skew adjustment device 100 in the direction indicated by arrow A52, which is parallel to the direction of arrow A51.

[0042] In this case, by displacing the orientation of the levitation conveying device 120 in the skew adjustment device 100 in the direction of the lap axis from the direction of line 120AX shown in Figure 4 to the direction of 129AX, the amount of displacement of the lap axis on the end OS side in the direction of the lap angle becomes relatively larger, and the amount of displacement of the lap axis on the end DS side in the direction of the lap angle becomes relatively smaller, and the path length L OS An adjustment is achieved such that the relative length becomes longer.

[0043] By making such adjustments and adjusting the degree of displacement so that the degree of skewing detected by the transport position sensor becomes smaller, the direction of travel of the web 12 downstream of the skewing adjustment device 100 can be changed to the direction indicated by arrow A53, which is the direction without skewing. Through such adjustments, the skewing adjustment device 100 can achieve skewing adjustment.

[0044] [Web Processing Device] The web processing apparatus of the present invention is a web processing apparatus that transports a long web along a transport path and subjects the web to a relaxation process along the transport path that causes it to contract in an oblique direction.

[0045] Here, relaxation treatment refers to a process performed on a web that results in the relaxation of internal stresses within the web. Specific examples of relaxation treatment include heating, humidification, and combinations thereof. Typically, such relaxation occurs unintentionally and undesirably as a result of desired treatments such as heating or humidification. However, relaxation treatment is not limited to these and may be intentionally induced.

[0046] Relaxation treatments that induce diagonal shrinkage typically involve applying heat treatment and humidification treatment to a film whose web has been pre-stretched diagonally. An example of a humidification treatment is applying a liquid to the substrate for film formation, etc. An example of a heat treatment is heating the applied liquid film to solidify it.

[0047] The web processing apparatus of the present invention comprises a relaxation device located on the transport path that performs relaxation processing, and a skew adjustment device of the present invention. By providing a skew adjustment device in combination with the relaxation device, the skew generated by the relaxation processing can be adjusted by the skew adjustment device, and as a result, the web can be transported on a transport path that does not skew, just like a web that does not skew, enabling efficient web processing. In the web processing apparatus, there may be only one relaxation device or there may be multiple relaxation devices. Similarly, there may be only one skew adjustment device or there may be multiple skew adjustment devices.

[0048] In the web processing apparatus of the present invention, the skew adjustment device is typically located near the downstream side of the relaxation device and adjusts the skew generated by the relaxation device downstream of it. However, the present invention is not limited to this, and the skew adjustment device may be located upstream of the relaxation device. Furthermore, for example, if there are multiple relaxation devices, the skew adjustment device may be provided between such multiple relaxation devices, so that the skew adjustment device is located downstream of one relaxation device and upstream of another relaxation device.

[0049] Alternatively, a skew adjustment device may be provided on the transport path inside the relaxation device, thereby arranging the device to be located inside the relaxation device. Such an arrangement is particularly useful when the relaxation device is a device with an internal cavity that extends along a long transport path, such as a heating oven.

[0050] [Method for manufacturing multilayer films] The adjustment of web skew using the skew adjustment device of the present invention described above can be used in a method for manufacturing a multilayer film that includes a diagonally stretched substrate and a coating layer provided on its surface. This will be described below as the method for manufacturing a multilayer film of the present invention.

[0051] The present invention provides a method for producing a multilayer film, comprising the following steps (I) to (III). Step (I): A step of applying a coating layer forming material onto the surface of a diagonally stretched substrate to form a coating film of the coating layer forming material. Process (II): A process in which the coating film is subjected to a curing treatment in the transport path to form a coating layer. Step (III): A diagonal adjustment step in which the diagonal direction of the conveyed object in the conveying path is adjusted using the diagonal adjustment device of the present invention.

[0052] The obliquely stretched substrate used in process (I) is a film that has been pre-stretched obliquely. Such films can be continuously manufactured upstream of process (I) and supplied to process (I). Alternatively, obliquely stretched films may be prepared in advance as film rolls, and the film may be unwound from these film rolls upstream of process (I).

[0053] The coating layer-forming material used in step (I) is usually a liquid, and by curing the coating film in step (II), a coating layer, which is the cured product of the coating film, is obtained. Since either or both of steps (I) and (II) may constitute the relaxation treatment described above, they may cause the obliquely stretched substrate to become skewed.

[0054] In process (III), the skewness of the conveying direction of the conveyed material in the conveying path is adjusted by a skew adjustment device. The conveyed material here may be a diagonally stretched substrate before being subjected to process (I), a diagonally stretched substrate with a coating film after being subjected to process (I) and before being subjected to process (II), a diagonally stretched substrate with a coating layer after being subjected to process (II), or two or more of these. By performing process (III) with these as the webs to be adjusted for skewness, the conveyed material can be transported in a non-skewed conveying path, similar to a web without skewness, enabling efficient manufacturing.

[0055] [Description of materials] The film supplied in step (I) of the manufacturing method of the present invention may be a resin film containing various polymers. Examples of such polymers include olefin polymers such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyarylene sulfides such as polyphenylene sulfide; polyvinyl alcohol; polycarbonate; polyarylate; cellulose ester; polyethersulfone; polysulfone; polyallylsulfone; polyvinyl chloride; alicyclic structure-containing polymers; acrylic polymers; styrene-based polymers such as polystyrene; and so on. These may be used individually or in combination of two or more in any ratio.

[0056] Preferably, the resin constituting the film is a resin containing an alicyclic structure-containing polymer (hereinafter referred to as "alicyclic structure-containing polymer resin" as appropriate), a resin containing an acrylic polymer, or a resin containing polycarbonate. Alicyclic structure-containing polymer resins are particularly preferred because they offer excellent transparency, low moisture absorption, dimensional stability, and lightweight properties, making them suitable for use as optical films. Specific examples of resins constituting the film are those described in Japanese Patent Publication No. 5845895.

[0057] An example of a coating liquid used for forming a coating layer in step (II) of the manufacturing method of the present invention is a polyurethane aqueous dispersion for forming a urethane resin layer. A specific example of a polyurethane aqueous dispersion is the one described in Japanese Patent Publication No. 5845895.

[0058] [Applications of multilayer films] The multilayer film obtained by the manufacturing method of the present invention can be used as a component of a display device such as a liquid crystal display device or an organic electroluminescent display device. In particular, since the obliquely stretched substrate can be a component having a phase difference in the oblique direction, when used as a phase difference film, it can be usefully used as a phase difference film having a slow phase axis in the desired direction with a high yield. [Explanation of Symbols]

[0059] 11: Long roll of film 12: Web (film) 100: Diagonal adjustment device 112: Heat treatment apparatus 120: Levitation conveying device 120AX: Line indicating the direction of the wrap axis. 120C: Center position of the levitation conveying device 121: Conveyor surface 129AX: Line indicating the direction of the wrap 131: Upstream support roller 132: Downstream support roller 133: Support roller 140: Support device 181: Conveyor position sensor A1: Conveying direction A11: Orientation axis A121: Direction that bisects the wrap angle A140: Direction of rotation of the support device A51: Direction of Web Progress A52: Direction of Web Progress A53: Direction of Web Progress DS: End DS side OS: End OS side θw: wrap angle

Claims

1. A web processing apparatus for transporting a long web along a transport path and subjecting the web to a relaxation process that causes it to contract in an oblique direction along the transport path, A relaxation device located on the aforementioned transport path, and Diagonal adjustment device Equipped with, The aforementioned diagonal adjustment device is A diagonal adjustment device for adjusting the diagonal direction of a long web in the transport path, Floating transport device, and A transport position sensor located downstream of the aforementioned levitation transport device. Equipped with, The levitation conveying device extends from one end DS to the other end OS in the width direction of the web of the conveying path and has a conveying curved surface that supports the web without contact. The levitation conveying device is provided such that the conveying curved surface is wrapped by the conveying path, The levitation conveying device is equipped with a path length adjustment mechanism that can adjust the path length L DS of the conveying path at the end DS and the path length L OS of the conveying path at the end OS so that they are relatively different in length. The transport position sensor is a sensor that detects the transport position in the width direction of the web, The web processing device is a skew adjustment device, wherein the path length adjustment mechanism adjusts the path length L DS and the path length L OS so that the path length L OS becomes relatively longer when the transport position sensor detects the skew where the path is tilted towards the end DS, and adjusts the path length L DS to become relatively longer when the transport position sensor detects the skew where the path is tilted towards the end OS.

2. The web processing apparatus according to claim 1, wherein the oblique adjustment device is located upstream of the mitigation device, downstream of the mitigation device, or inside the mitigation device.

3. The path length adjustment mechanism is a mechanism that adjusts the amount of displacement of the conveying curved surface in the direction of the wrap axis in the direction of the wrap angle, The web processing apparatus according to claim 1 or 2, wherein the amount of displacement becomes relatively larger at the end OS, causing the path length L OS to become relatively longer, and the amount of displacement becomes relatively larger at the end DS, causing the path length L DS to become relatively longer.

4. The web processing apparatus according to any one of claims 1 to 3, wherein the floating conveying apparatus comprises a surface of a porous material having a large number of holes as the conveying curved surface, and is configured to eject gas from the holes.

5. A method for manufacturing a multilayer film, comprising a diagonally stretched substrate and a coating layer provided on its surface, The aforementioned manufacturing method is A step of applying a coating layer forming material to the surface of the obliquely stretched substrate and forming a coating film of the coating layer forming material, A step of subjecting the coating film to a curing treatment in the transport path to form a coating layer, and A diagonal adjustment step in which the diagonal direction of the conveyed object in the aforementioned conveying path is adjusted by a diagonal adjustment device. Includes, The aforementioned diagonal adjustment device is A diagonal adjustment device for adjusting the diagonal direction of a long web in the transport path, Floating transport device, and A transport position sensor located downstream of the aforementioned levitation transport device. Equipped with, The levitation conveying device extends from one end DS to the other end OS in the width direction of the web of the conveying path and has a conveying curved surface that supports the web without contact. The levitation conveying device is provided such that the conveying curved surface is wrapped by the conveying path, The levitation conveying device is equipped with a path length adjustment mechanism that can adjust the path length L DS of the conveying path at the end DS and the path length L OS of the conveying path at the end OS so that they are relatively different in length. The transport position sensor is a sensor that detects the transport position in the width direction of the web, A method for manufacturing a multilayer film, comprising a path length adjustment mechanism which adjusts the path lengths L DS and L OS such that the path length L OS becomes relatively longer when the transport position sensor detects the skew where the film is tilted toward the end DS, and adjusts the path length L DS to become relatively longer when the transport position sensor detects the skew where the film is tilted toward the end OS, and a skew adjustment device.

6. The path length adjustment mechanism is a mechanism that adjusts the amount of displacement of the conveying curved surface in the direction of the wrap axis in the direction of the wrap angle, The method for manufacturing a multilayer film according to claim 5, wherein the amount of displacement becomes relatively larger at the end OS, causing the path length L OS to become relatively longer, and the amount of displacement becomes relatively larger at the end DS, causing the path length L DS to become relatively longer.

7. The method for manufacturing a multilayer film according to claim 5 or 6, wherein the levitation conveying device is configured to have a surface of a porous material having a large number of holes as the conveying curved surface, and to be able to eject gas from the holes.

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