JP6910833B2 - Resin film transport method - Google Patents

Description

The present invention relates to a method for conveying a resin film, and also relates to a method for producing a laminated film, an apparatus for conveying a resin film, and an apparatus for producing a laminated film.

For example, in an image display device using an optical display device such as a liquid crystal display element, various optical films such as an optical compensation film (phase difference film), a polarizer protective film, and an antireflection film are used.

In the production of such an optical film, for example, as described in Patent Document 1, a long strip-shaped resin film is produced by extrusion molding of a thermoplastic resin. Further, the resin film may be stretched in the width direction (horizontal direction). By this lateral stretching, the resin film is imparted with desired optical properties and toughness. Specifically, while continuously transporting the long strip-shaped thermoplastic resin film in the length direction, both ends of the resin film are gripped by clips. Then, the resin film is stretched in the width direction by increasing the distance between the clips. Further, the laminated film (laminated optical film) is completed through a step of laminating the stretched resin film with another resin film (for example, a protective film).

Japanese Unexamined Patent Publication No. 2010-36414

Both ends of the resin film gripped by the clip in the transverse stretching remain with substantially the same thickness as the thermoplastic resin film before stretching. On the other hand, the portion between both ends becomes thinner due to stretching. Therefore, both ends of the stretched resin film are cut and removed by slitting, and the width of the resin film is adjusted to a predetermined width. The stretched film adjusted to a predetermined width is usually wound into a roll and then shipped as a product.

As described above, since there is a difference in thickness between both end portions and the center portion of the stretched film, wrinkles are likely to occur in the stretched film during transportation before slitting. If wrinkles are generated near both ends of the stretched film before slitting, defects are likely to occur at the time of slitting. In addition, film pieces (powder) due to poor slits may be mixed into the finished product. Further, the wrinkles of the stretched film also cause the uniformity of the optical characteristics of the optical film to be impaired. In particular, when the resin film is made of a relatively brittle and fragile thermoplastic resin such as polymethyl methacrylate (PMMA) and polystyrene (PS), the slits are caused by the wrinkles generated before the slit processing. Not only is it easy for film pieces to get mixed in due to defects, but the stretched film may also break.

The wrinkles of the resin film as described above are not necessarily caused only by lateral stretching. For example, in extrusion molding of a thermoplastic resin, the resin film discharged from the ejection port (lip) of the extrusion die is affected by the neck-in at the time of ejection, so that the central portion of the resin film in the width direction is from the end. Also tends to thicken. That is, in resin extrusion molding, both ends of the resin film tend to be thicker than the central portion of the resin film. Not limited to this example, in various steps in the transport of the resin film or the production of the laminated film, a technique for suppressing wrinkles of the resin film due to the difference in the thickness of the resin film is required.

The present invention has been made in view of the above-mentioned problems of the prior art, and can suppress wrinkles of the resin film, a resin film transport method, a laminated film manufacturing method, a resin film transport device, and a laminate. It is an object of the present invention to provide a film manufacturing apparatus.

The method for transporting a resin film according to one aspect of the present invention includes a step of sandwiching and transporting the first resin film and the second resin film between the first roll and the second roll in a state of being overlapped with each other, and the first roll , The crown roll, and the first resin film and the second resin film are allowed to enter between the first roll and the second roll from the first roll side.

In the method for transporting a resin film according to one aspect of the present invention, a second resin film is transported in a direction perpendicular to the transport direction of the second resin film before the second resin film enters between the first roll and the second roll. At least one end of both ends of the resin film may be thicker than the central portion of the second resin film located between the both ends.

The "both ends of the second resin film" are both ends of the second resin film in a direction perpendicular to the transport direction of the second resin film. The "both ends of the second resin film" may be rephrased as both ends of the second resin film in a direction parallel to the rotation axis of the second roll. The "both ends of the second resin film" may be rephrased as both ends of the second resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped second resin film. The transport direction of the second resin film may be rephrased as the longitudinal direction of the second resin film.

In the method for transporting a resin film according to one aspect of the present invention, the width of the contact region in contact with the first resin film on the surface of the first roll may be narrower than the width of the second resin film in contact with the second roll. ..

The "width of the contact area" of the first roll is the width of the contact area of the first roll in the direction perpendicular to the transport direction of the first resin film. The "width of the contact area" of the first roll may be rephrased as the width of the contact area of the first roll in the direction parallel to the rotation axis of the first roll. The "width of the contact area" of the first roll may be rephrased as the width of the contact area of the first roll in the direction perpendicular to the longitudinal direction of the long strip-shaped first resin film. The transport direction of the first resin film may be rephrased as the longitudinal direction of the first resin film.

The "width of the second resin film" is the width of the second resin film in the direction perpendicular to the transport direction of the second resin film. The "width of the second resin film" may be rephrased as the width of the second resin film in the direction parallel to the rotation axis of the second roll. The "width of the second resin film" may be rephrased as the width of the second resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped second resin film.

In the method for transporting a resin film according to one aspect of the present invention, the first resin film is first in a direction perpendicular to the transport direction of the first resin film before the first resin film enters between the first roll and the second roll. At least one end of both ends of the resin film may be thicker than the central portion of the first resin film located between the both ends.

The "both ends of the first resin film" are both ends of the first resin film in a direction perpendicular to the transport direction of the first resin film. The "both ends of the first resin film" may be rephrased as both ends of the first resin film in a direction parallel to the rotation axis of the first roll. The "both ends of the first resin film" may be rephrased as both ends of the first resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped first resin film. The transport direction of the first resin film may be rephrased as the longitudinal direction of the first resin film.

In the method for transporting a resin film according to one aspect of the present invention, the width of the contact region in contact with the first resin film on the surface of the first roll may be narrower than the width of the first resin film.

The "width of the first resin film" is the width of the first resin film in the direction perpendicular to the transport direction of the first resin film. The "width of the first resin film" may be rephrased as the width of the first resin film in the direction parallel to the rotation axis of the first roll. The "width of the first resin film" may be rephrased as the width of the first resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped first resin film.

In the method for transporting a resin film according to one aspect of the present invention, the entire surface of the first resin film may be brought into contact with the surface of the first roll.

The method for producing a laminated film according to one aspect of the present invention is a method for producing a laminated film in which a first resin film and a second resin film are laminated, and the first resin film and the second resin film are laminated with each other. It is provided with a transport process of sandwiching and transporting the first roll and the second roll in an overlapping state, the first roll is a crown roll, and in the transport process, the first resin film and the second resin film are transferred to the first roll side. To enter between the first roll and the second roll.

In the method for producing a laminated film according to one aspect of the present invention, the second resin film is in a direction perpendicular to the transport direction of the second resin film before the second resin film enters between the first roll and the second roll. At least one end of both ends of the resin film may be thicker than the central portion of the second resin film located between the both ends.

In the method for producing a laminated film according to one aspect of the present invention, the width of the contact region in contact with the first resin film on the surface of the first roll may be narrower than the width of the second resin film in contact with the second roll. ..

In the method for producing a laminated film according to one aspect of the present invention, the first resin film is first in a direction perpendicular to the transport direction of the first resin film before the first resin film enters between the first roll and the second roll. At least one end of both ends of the resin film may be thicker than the central portion of the first resin film located between the both ends.

In the method for producing a laminated film according to one aspect of the present invention, the width of the contact region in contact with the first resin film on the surface of the first roll may be narrower than the width of the first resin film.

In the method for producing a laminated film according to one aspect of the present invention, the entire surface of the first resin film may be brought into contact with the surface of the first roll.

In the method for producing a laminated film according to one aspect of the present invention, in the transport step, an adhesive or an adhesive is interposed between the first resin film and the second resin film, and the first resin film and the second resin film are interposed. The first resin film and the second resin film may be bonded by sandwiching the first roll and the second roll.

In the method for producing a laminated film according to one aspect of the present invention, at least one of the first resin film and the second resin film may be a self-adhesive film.

The resin film transporting device according to one aspect of the present invention includes a first roll and a second roll that sandwich and transport the first resin film and the second resin film in a state of being overlapped with each other, and the first roll is a crown roll. The first resin film and the second resin film are configured to enter between the first roll and the second roll from the first roll side.

The laminated film manufacturing apparatus according to one aspect of the present invention is an apparatus for producing a laminated film in which a first resin film and a second resin film are laminated, and includes the above-mentioned transport device.

The laminated film manufacturing apparatus according to one aspect of the present invention adheres to at least one surface of the first resin film facing the second resin film or the surface of the second resin film facing the first resin film. A coating device for applying the agent or adhesive may be further provided.

According to the present invention, there are provided a method for conveying a resin film, a method for producing a laminated film, an apparatus for conveying a resin film, and an apparatus for producing a laminated film, which can suppress wrinkles of the resin film.

It is a schematic diagram of the resin film transporting apparatus and transporting method which concerns on 1st Embodiment of this invention, and shows the case where the approach angle θ1 of the 1st resin film is an obtuse angle. It is a modification of the transport device and the transport method shown in FIG. 1, and shows a case where the approach angle θ1 of the first resin film is an acute angle. It is a schematic diagram of the cross section of the transport device, the 1st resin film and the 2nd resin film shown in FIG. 1, and shows the cross section including the rotation axis of the 1st roll and the rotation axis of the 2nd roll. It is a schematic enlarged view of the cross section of the second resin film (stretched film) before the transport process of 1st Embodiment. It is a modification of the cross section shown in FIG. 3, and shows the case where the entire surface of the first resin film is in close contact with the surface (contact region) of the first roll. It is a schematic diagram of the cross section of the resin film transporting apparatus, the 1st resin film and the 2nd resin film which concerns on 2nd Embodiment of this invention. It is a schematic enlarged view of the cross section of the first resin film (stretched film) before the transport process of 2nd Embodiment. It is a schematic diagram of the transport device and the transport method of the resin film which concerns on Comparative Example 1. It is a schematic diagram of the transport device and the transport method of the resin film which concerns on Comparative Example 2.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the drawings, equivalent components are designated by the same reference numerals. The present invention is not limited to the following embodiments. X, Y and Z shown in each figure mean three coordinate axes orthogonal to each other. The direction indicated by each coordinate axis is common to all drawings.

(First Embodiment)
The first embodiment of the present invention relates to a method and an apparatus for producing a laminated film in which a protective film and a stretched film are laminated. The first embodiment relates to a method and an apparatus for conveying a protective film and a stretched film. In the first embodiment, the first resin film is a protective film. However, as described later, the first resin film does not have to be a protective film. In the first embodiment, the second resin film is a thermoplastic stretched film. The stretched film is a resin film to which desired properties such as optical properties or toughness are imparted by, for example, one or both of longitudinal stretching and transverse stretching. Specific examples of the stretched film are, for example, a retardation film, a polarizer, or a polarizer protective film. However, as described later, the second resin film does not have to have thermoplasticity and does not have to be a stretched film. In the following, a laminate including a protective film and a stretched film that are directly or indirectly overlapped with each other will be referred to as a laminated film. The first resin film may be a single-layer film having a single-layer structure or a multilayer film having a multi-layer structure. Further, the second resin film may be a single-layer film having a single-layer structure or a multilayer film having a multi-layer structure. Both the first resin film and the second resin film may be a single-layer film, or both may be a multilayer film. The first resin film may be a single-layer film, and the second resin film may be a multilayer film. The first resin film may be a multilayer film, and the second resin film may be a single layer film.

The thermoplastic resin constituting the stretched film may be a translucent thermoplastic resin, preferably an optically transparent thermoplastic resin. The thermoplastic resin may be, for example, a polyolefin-based resin such as a chain polyolefin-based resin, a cyclic polyolefin-based resin (for example, norbornene-based resin), a polyethylene-based resin, or a polypropylene-based resin. The thermoplastic resin may be a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, or poly-L-lactic acid. The thermoplastic resin may be a (meth) acrylic resin such as a methyl methacrylate resin. The thermoplastic resin may be a cellulosic resin such as cellulose triacetate or cellulosic diacetate. The thermoplastic resin is a polycarbonate resin, a polyvinyl alcohol resin, a polyvinyl acetate resin, a polyarylate resin, a polystyrene resin, a polyether sulfone resin, a polysulfone resin, a polyamide resin, or a polyimide resin. May be good. The thermoplastic resin may be a mixture or copolymer of the above resins. The thermoplastic resin may further contain additives, if necessary. Additives may be, for example, antioxidants, UV absorbers, antistatic agents, lubricants, nucleating agents, anti-fog agents, or anti-blocking agents. For example, when a polarizer is produced as a stretched film, the thermoplastic resin may be a polyvinyl alcohol-based resin.

The resin constituting the protective film may be a polyethylene-based resin, a polypropylene-based resin, or a polyester-based resin (for example, polyethylene terephthalate). An adhesive layer may be formed on the surface of the protective film facing the stretched film.

The stretched film is produced, for example, through an extrusion molding step, a longitudinal stretching step, and a transverse stretching step described below. A stretched film may be produced through a longitudinal stretching step and then a transverse stretching step, or a stretched film may be produced through a longitudinal stretching step and then a longitudinal stretching step. Further, a stretched film may be produced through a transverse stretching step after undergoing an extrusion molding step. Hereinafter, a case where the transverse stretching step is performed after the longitudinal stretching step will be described.

In the extrusion step, the heat-melted thermoplastic resin is continuously extruded from a discharge port (lip) provided at the tip of the extruder to be formed into a film. By cooling the molded product by passing it through a plurality of cooling rolls, a long strip-shaped extruded film can be obtained. The extruded film may be continuously conveyed to the longitudinal stretching apparatus as it is. Alternatively, the extruded film may be wound into a roll shape, and then the roll-shaped extruded film may be unwound and conveyed to a longitudinal stretching apparatus. The extruded film is conveyed along its longitudinal direction.

The longitudinal stretching device includes, for example, at least two nip rolls arranged apart from each other. The nip roll is a device composed of a pair of rolls, sandwiching a resin film between the pair of rolls, and transporting the resin film while applying pressure. In the longitudinal stretching step, the extruded film passes through two nip rolls provided in the longitudinal stretching apparatus. The peripheral speed of the nip roll through which the extruded film first passes is adjusted to be slower than the peripheral speed of the nip roll through which the extruded film passes next. Due to this difference in peripheral speed, the extruded film is stretched in the longitudinal direction (conveying direction) to become a longitudinally stretched film. In the longitudinal stretching step, an oven or the like may be placed between the two nip rolls to stretch the extruded film while heating it. The extruded film may be preheated prior to the longitudinal stretching step.

A transverse stretching step is carried out following the longitudinal stretching step. Hereinafter, the tenter method will be described as an example of the transverse stretching step. The transverse stretching apparatus used in the tenter method includes, for example, two rows of clips arranged along both ends of the longitudinally stretched film. That is, the longitudinally stretched film is placed between the two clip rows. Each clip row is composed of a plurality of clips. That is, a plurality of clips are lined up along both ends of the longitudinally stretched film. Both ends of the longitudinally stretched film are gripped by each clip. In the transverse stretching step, a longitudinally stretched film whose both ends are gripped by a plurality of clips is conveyed in the longitudinal direction thereof. In the process of transporting, the vertically stretched film becomes a horizontally stretched film by widening the distance between the pair of clips facing each other in the width direction (horizontal direction) of the vertically stretched film. After increasing the distance between the pair of clips, an operation (so-called relaxation) that slightly narrows the distance may be performed. Then, both ends of the transversely stretched film are released from the clips. The pair of clips released from the transversely stretched film return to the upstream side and grip both ends of the vertically stretched film again. That is, the plurality of clips repeatedly grip both ends of the longitudinally stretched film, laterally stretch the longitudinally stretched film, and open the transversely stretched film. By the above tenter method, the longitudinally stretched film is continuously stretched in the width direction (horizontal direction) to obtain a transversely stretched film. Also in the transverse stretching step, the longitudinally stretched film may be stretched while being heated. During the transverse stretching step or after the transverse stretching step, heat fixing may be performed to heat and stabilize the transversely stretched film. The stretched film after the transverse stretching is guided by a plurality of guide rolls and transported to a transport device described later.

The thickness of both ends of the vertically stretched film gripped by the clip is almost the same as the thickness before the transverse stretching even after the transverse stretching. On the other hand, the portion (central portion) located between both end portions of the vertically stretched film tends to be thinned by lateral stretching. That is, as shown in FIG. 4, both end portions 8b of the transversely stretched film 8 tend to be thicker than the central portion 8a of the transversely stretched film 8 located between the both end portions 8b. The thickness T8a of the central portion 8a of the transversely stretched film 8 tends to be uniform. Therefore, both end portions 8b of the transversely stretched film 8 are cut and removed by the subsequent slit processing, and the width W8 of the transversely stretched film 8 is adjusted to a predetermined width (for example, width W8a). However, when the transversely stretched film 8 is conveyed to the slit processing apparatus by a conventional conveying method using a guide roll or a nip roll, wrinkles are likely to occur in the transversely stretched film 8 during transportation. In particular, in the transversely stretched film 8, wrinkles from both end portions 8b toward the center portion 8a and wrinkles from the center portion 8a toward both end portions 8b are likely to occur. This wrinkle is caused by the difference between the thickness T8b of both end portions 8b and the thickness T8a of the central portion 8a of the transversely stretched film 8. According to the transport device and the transport method described in detail below, wrinkles in the transversely stretched film 8 (second resin film) during transport can be suppressed. However, the wrinkles in the stretched film during transportation are not necessarily caused only by the difference in thickness. Even when there is almost no difference in thickness in the transversely stretched film 8, wrinkles in the transversely stretched film 8 during transportation can be suppressed according to the transfer device and the transfer method according to the first embodiment.

As shown in FIGS. 1 to 3, the laminated film manufacturing apparatus according to the first embodiment includes a transport device 100 for transporting the protective film 6 and the transversely stretched film 8. The transport device 100 includes a first roll 1 and a second roll 2. The rotation axis A1 of the first roll 1 is parallel to the rotation axis A2 of the second roll 2. In the transporting step, the protective film 6 and the transversely stretched film 8 are sandwiched between the first roll 1 and the second roll 2 in a state of being overlapped with each other and transported. The protective film 6 also has a long strip shape like the transversely stretched film 8. The protective film 6 is, for example, unwound from the original roll and supplied to the transport device 100.

The first roll 1 and the second roll 2 are nip rolls that apply linear pressure to the surface of the resin film. That is, the protective film 6 and the transversely stretched film 8 are sandwiched between the first roll 1 and the second roll 2 in the process of transportation, and are pressed by the first roll 1 and the second roll 2. For example, by controlling the speed of the nip roll, the tensions of the protective film 6 and the transversely stretched film 8 located on the upstream side of the nip roll can be controlled.

The first roll 1 is a crown roll. That is, as shown in FIG. 3, in the cross section including the rotation axis A1 of the first roll 1, the surface of the contact region 1a located at the center of the first roll 1 is a gentle curve. Then, the diameter (thickness) of the first roll 1 decreases from the center of the first roll 1 toward both end portions 1b of the first roll 1. On the other hand, the second roll 2 may be, for example, a flat roll having a substantially uniform diameter. That is, as shown in FIG. 3, the surface of the second roll 2 is a straight line in the cross section including the rotation axis A2 of the second roll 2. However, the actual second roll 2 may be bent along the contact region 1a of the first roll 1 due to its own weight, for example.

The method for producing a laminated film according to the first embodiment includes a transfer step using the transfer device 100. In the transfer step, the protective film 6 and the transversely stretched film 8 are brought into the space between the first roll 1 and the second roll 2 from the first roll 1 side. That is, the protective film 6 and the transversely stretched film 8 are allowed to enter between the rolls from the crown roll side. As a result, the first roll 1 can easily apply linear pressure to the protective film 6 and the transversely stretched film 8. Further, since the contact region 1a (thick portion of the crown roll) of the first roll 1 is convex as compared with the flat roll, it is easy to come into contact with the surface of the protective film 6. Due to the approach direction of each resin film and the shape of the first roll 1 (crown roll) as described above, the first roll 1 is sufficient for the central portion 8a of the laterally stretched film 8 via the protective film 6. A linear pressure can be applied. As the linear pressure is applied, tension can be applied to the central portion 8a of the laterally stretched film 8 located on the upstream side of the transport device 100, so that the wrinkles and the central portion 8a toward the central portion 8a of the laterally stretched film 8 can be applied. Wrinkles toward both ends 8b are less likely to occur. Further, even if wrinkles are generated in the transversely stretched film 8 located on the upstream side of the transport device 100, the wrinkles of the transversely stretched film 8 are spread and eliminated due to the shape of the first roll 1 (crown roll). By the above mechanism, wrinkles in the transversely stretched film 8 during transportation are suppressed. If one or both of the protective film 6 and the transversely stretched film 8 are allowed to enter between the first roll 1 and the second roll 2 from the second roll 2 side, the contact region 1a of the first roll 1 (of the crown roll). The thick portion) makes it difficult to apply the linear pressure to the central portion 8a of the transversely stretched film 8, and it becomes difficult to suppress wrinkles. Further, even when the first roll 1 is a flat roll, it becomes difficult for the first roll 1 to apply a linear pressure to the central portion 8a of the transversely stretched film 8, and it becomes difficult to suppress wrinkles.

As shown in FIGS. 1 and 2, in a cross section (ZX plane) perpendicular to the rotation axis A1 of the first roll 1 and the rotation axis A2 of the second roll 2, the first reference line L1 is the rotation axis A1 and the rotation axis. A line segment that is perpendicular to the line segment La connecting A2 and intersects with the protective film 6 (first resin film). The approach angle θ1 of the protective film 6 (first resin film) is defined as the angle formed by the protective film 6 (first resin film) with respect to the first reference line L1. Further, in the cross section perpendicular to the rotation axis A1 and the rotation axis A2, the second reference line L2 is a line segment that is perpendicular to the line segment La and intersects with the transversely stretched film 8 (second resin film). Approach angle θ2 of transversely stretched film 8 (second resin film), transversely stretched film 8 (second resin film) is defined as the angle with respect to the second reference line L2.

As shown in FIG. 1, the approach angle θ1 of the protective film 6 may be an obtuse angle. As shown in FIG. 2, the approach angle θ1 of the protective film 6 may be an acute angle. The approach angle θ1 of the protective film 6 may be, for example, 10 to 170 °. In order to increase the wrinkle suppressing effect caused by the shape of the first roll 1, the approach angle θ1 is preferably 30 to 120 °. As shown in FIG. 1, the approach angle θ2 of the transversely stretched film 8 may be an acute angle. The approach angle θ2 of the transversely stretched film 8 may be an obtuse angle. For example, the approach angle θ2 of the transversely stretched film 8 may be 10 to 170 °. When the approach angles θ1 and θ2 are within the above ranges, wrinkles of the transversely stretched film 8 are likely to be suppressed.

Before the transversely stretched film 8 enters between the first roll 1 and the second roll 2, both ends of the transversely stretched film 8 in a direction perpendicular to the transport direction D8 of the transversely stretched film 8 as shown in FIG. The portion 8b may be thicker than the central portion 8a of the laterally stretched film 8 located between the both end portions 8b. That is, both end portions 8b of the laterally stretched film 8 in the width direction (short direction or Y-axis direction) may be thicker than the central portion 8a of the laterally stretched film 8 located between both end portions 8b. In the transverse stretching step, the thickness T8b of both end portions 8b of the transverse stretching film 8 becomes larger than the thickness T8a of the central portion 8a, and wrinkles toward the central portion 8a and wrinkles from the central portion 8a toward both end portions 8b are likely to occur. Further, in the transporting step, the contact region 1a of the first roll 1 can uniformly apply tension to the central portion 8a of the transversely stretched film 8 via the protective film 6, so that the wrinkles of the transversely stretched film 8 are formed. It can be suppressed. Further, even if wrinkles are generated in the transversely stretched film 8 located on the upstream side of the transport device 100, the wrinkles of the transversely stretched film 8 are spread and eliminated due to the shape of the first roll 1 (crown roll).

As shown in FIG. 3, a part of the surface of the protective film 6 (first resin film) may be brought into close contact with the surface of the first roll 1 (contact region 1a of the first roll 1), or is shown in FIG. As described above, the entire surface of the protective film 6 (first resin film) may be brought into close contact with the surface of the first roll 1 (contact region 1a of the first roll 1). The larger the surface area of the protective film 6 (first resin film) that adheres to the surface of the first roll 1 (contact region 1a of the first roll 1), the larger the contact region 1a of the first roll 1 becomes the protective film 6 (first). The linear pressure is easily applied to the central portion 8a of the transversely stretched film 8 (second resin film) via the resin film). As a result, wrinkles toward the central portion 8a of the transversely stretched film 8 and wrinkles from the central portion 8a toward both end portions 8b are unlikely to occur. Further, even if wrinkles are generated in the transversely stretched film 8 located on the upstream side of the transport device 100, the wrinkles of the transversely stretched film 8 are likely to spread due to the shape of the first roll 1 (crown roll).

The width W1a of the contact region 1a in contact with the protective film 6 (first resin film) on the surface of the first roll 1 is narrower than the width W8 of the laterally stretched film 8 (second resin film) in contact with the second roll 2. It's okay. When the width W1a of the contact region 1a in contact with the first roll 1 is narrower than the width W8 of the transversely stretched film 8 (second resin film), the contact region 1a of the first roll 1 is the transversely stretched film 8 (second resin). It is difficult for the first roll 1 to hit both end portions 8b (thicker portion than the central portion 8a) of the film), and the tension is easily applied only to the central portion 8a of the transversely stretched film 8 (second resin film). By applying tension only to the central portion 8a of the transversely stretched film 8 (second resin film), wrinkles toward the central portion 8a of the transversely stretched film 8 (second resin film) and toward both ends 8b from the central portion 8a. Wrinkles are less likely to occur. Further, even if wrinkles are generated in the transversely stretched film 8 located on the upstream side of the transport device 100, the wrinkles of the transversely stretched film 8 are likely to spread due to the shape of the first roll 1 (crown roll). The difference (W8-W1a) between the width W8 of the transversely stretched film 8 (second resin film) and the width W1a of the contact region 1a of the first roll 1 may be, for example, about 10 to 300 mm.

As shown in FIG. 3, the width W6 of the protective film 6 (first resin film) may be narrower than the width W1a of the contact region 1a of the first roll 1. When the width W6 of the protective film 6 (first resin film) is narrower than the width W1a of the contact region 1a of the first roll 1, the contact region 1a of the first roll 1 applies linear pressure to the protective film 6 and the transversely stretched film 8. Easy to give. However, the width W6 of the protective film 6 (first resin film) may be wider than the width W1a of the contact region 1a of the first roll 1. As shown in FIG. 3, the width W6 of the protective film 6 (first resin film) may be narrower than the width W8 of the transversely stretched film 8 (second resin film). However, the width W6 of the protective film 6 (first resin film) may be wider than the width W8 of the transversely stretched film 8 (second resin film). As shown in FIG. 3, the width W8 of the transversely stretched film 8 (second resin film) may be narrower than the width W2 of the second roll 2.

As shown in FIG. 3, in the transport process, the central portion of the first roll 1, the central portion of the protective film 6 (first resin film), the central portion of the transversely stretched film 8 (second resin film), and the second roll. The central portions of 2 may be aligned on the same plane (ZX plane) or on the same straight line (Z axis).

The surface of the first roll 1 may be a rigid body having high rigidity. For example, the surface of the first roll 1 may be a metal such as iron or stainless steel (SUS304). The surface of the first roll 1 may be an elastic body. For example, the surface of the first roll 1 may be a rubber such as nitrile rubber (NBR), urethane rubber, silicone rubber, or ethylene / propylene / diene rubber (EPDM). The surface of the first roll 1 is preferably an elastic body because it is easy to give the crown shape to the first roll 1.

The surface of the second roll 2 may be a rigid body having high rigidity. For example, the surface of the second roll 2 may be made of a metal such as iron or stainless steel (SUS304), and the surface of the second roll 2 may be surface-treated such as chrome plating or nickel plating. .. The surface of the second roll 2 may be an elastic body. For example, the surface of the second roll 2 may be a rubber such as nitrile rubber (NBR), urethane rubber, silicone rubber, or ethylene / propylene / diene rubber (EPDM).

It is preferable that the surface of the first roll 1 is an elastic body and the surface of the second roll 2 is a rigid body because both the wrinkle suppressing effect and the uniform bonding pressure can be achieved.

One or both of the first roll 1 and the second roll 2 may rotate by being driven directly or indirectly by a power source (eg, a motor).

The protective film 6 and the transversely stretched film 8 are fed out from between the first roll 1 and the second roll 2 as the laminated film 4. The laminated film 4 is guided by a plurality of guide rolls and conveyed to the slit processing apparatus. In the slit processing step using the slit processing device, both end portions 8b of the transversely stretched film 8 are cut (slit) and removed. When the protective film 6 overlaps any of both end portions 8b of the transversely stretched film 8, a part of the protective film 6 overlapping the both end portions 8b of the transversely stretched film 8 is also cut (slit) and removed.

Another resin film may be laminated or bonded to the laminated film 4 after the slit processing. For example, a protective film (second resin film) different from the protective film 6 may be laminated or bonded to the stretched film, and the stretched film may be sandwiched between the pair of protective films. In addition to the second resin film, one or more other resin films may be laminated or bonded to the laminated film 4.

Before the transversely stretched film 8 enters between the first roll 1 and the second roll 2, the thickness T8a of the central portion 8a of the transversely stretched film 8 is, for example, 3 to 100 μm, 4 to 80 μm, or 5 to 5. It may be 40 μm. In the conventional transfer process, the smaller the thickness T8a of the central portion 8a of the transversely stretched film 8, the more easily wrinkles tend to occur in the transversely stretched film 8. In other words, the thinner the central portion 8a of the transversely stretched film 8, the more difficult it is to uniformly apply tension in the width direction of the transversely stretched film 8 due to the influence of wrinkles and the like, and the higher the tension of the transversely stretched film 8 is. The transversely stretched film 8 was easily broken. Therefore, in the conventional transfer process, it is difficult to suppress the wrinkles in the thin transversely stretched film 8 by tension. However, according to the first embodiment, even when the thickness T8a of the central portion 8a of the transversely stretched film 8 is 40 μm or less, wrinkles of the transversely stretched film 8 during transportation are suppressed and the transversely stretched film 8 is broken. Can be suppressed. The thickness of the protective film 6 may be, for example, about 10 to 100 μm.

The width W8 of the transversely stretched film 8 may be, for example, 300 to 6000 mm. The wider the width W8 of the transversely stretched film 8 (particularly, the width W8a of the central portion 8a of the transversely stretched film 8), the more likely it is that wrinkles will occur in the laterally stretched film 8 during transportation. However, according to the first embodiment, even when the width W8 of the transversely stretched film 8 is wide, wrinkles of the transversely stretched film 8 during transportation can be suppressed. The width W6 of the protective film 6 may be, for example, 300 to 6000 mm.

The transport speed of the protective film 6 and the transversely stretched film 8 may be, for example, 2 to 100 m / min.

The diameter of the contact region 1a of the first roll 1 (crown roll) may be, for example, 60 to 400 mm. The diameter of the second roll 2 may be, for example, 60 to 400 mm.

The crown amount of the first roll 1 (crown roll) may be, for example, 0.05 to 5 mm. The crown amount is the difference between the maximum value and the minimum value of the diameter in the contact region 1a of the first roll 1. In other words, the crown amount is the difference between the diameter of the central portion of the contact region 1a of the first roll 1 and the diameter of the end portion of the contact region 1a of the first roll 1. The crown amount of the first roll 1 is a value obtained by subtracting the bending amount of the second roll 2 from the bending amount of the first roll 1 (difference in the bending amount), and the difference in the bending amount is a positive value. The larger the difference in the amount of bending, the easier it is for the first roll 1 to apply linear pressure to the central portion 8a of the protective film 6 and the transversely stretched film 8, and it becomes easier to suppress wrinkles. However, if the difference in the amount of deflection (positive value) is too large, the edge portion in the width direction of each film is not nipated, so that the wrinkle suppressing effect may be reduced. Therefore, it is preferable that the crown amount is the difference in the amount of bending and is a positive value, and is within a range in which the end portion in the width direction of each film is nipped.

The laminated film obtained in the above first embodiment may be bonded to an optical display device such as a liquid crystal display element or an organic EL display element as a laminated optical film, for example. The laminated optical film may be, for example, a laminated polarizing plate.

(Second Embodiment)
A second embodiment of the present invention will be described. In the second embodiment as well, as in the case of the first embodiment, wrinkles in the stretched film during transportation can be suppressed. Hereinafter, matters specific to the second embodiment (differences between the first embodiment and the second embodiment) will be described. In matters not described below, the second embodiment is common to the first embodiment.

In the first embodiment, the first resin film 6 in contact with the first roll 1 (crown) is a protective film, and the second resin film 8 in contact with the second roll 2 is a stretched film. In contrast, in the second embodiment, the first resin film 6 in contact with the first roll 1 (crown) is the stretched film, and the second resin film 8 in contact with the second roll 2 is the protective film. The second embodiment is the same as the first embodiment except that the vertical relationship between the stretched film and the protective film is reversed.

The method for producing a laminated film according to the second embodiment also includes a transfer step using the transfer device 100. In the transfer step, the first resin film 6 (stretched film) and the second resin film 8 (protective film) are allowed to enter between the first roll 1 and the second roll 2 from the first roll 1 side. That is, the first resin film 6 and the second resin film 8 are made to enter between the rolls from the crown roll side. As a result, the first roll 1 can easily apply the linear pressure to the first resin film 6 and the second resin film 8. Further, since the contact region 1a of the first roll 1 is convex as compared with the flat roll, it is easy to come into contact with the surface of the first resin film 6 (stretched film). Due to the approach direction of each resin film and the shape of the first roll 1 (crown roll) as described above, as shown in FIGS. 6 and 7, the first roll 1 is the first resin film 6 (stretched). A linear pressure can be applied to the central portion 6a of the film). By this linear pressure, tension can be applied to the central portion 6a of the first resin film 6 (stretched film), so that wrinkles of the first resin film 6 (stretched film) can be suppressed. Further, even if wrinkles are generated on the first resin film 6 (stretched film) located on the upstream side of the transport device 100, the first resin film 6 (stretched film) is caused by the shape of the first roll 1 (crown roll). ) Wrinkles spread and disappear. By the above mechanism, wrinkles in the first resin film 6 (stretched film) during transportation are suppressed. In particular, wrinkles of the first resin film 6 (stretched film) are easily suppressed.

Before the first resin film 6 (stretched film) enters between the first roll 1 and the second roll 2, as shown in FIG. 7, in the transport direction D6 of the first resin film 6 (stretched film). Both end portions 6b of the first resin film 6 (stretched film) in the vertical direction may be thicker than the central portion 6a of the first resin film 6 (stretched film) located between both end portions 6b. That is, both end portions 6b of the first resin film 6 (stretched film) in the width direction (short direction or Y-axis direction) are central portions 6a of the first resin film 6 (stretched film) located between both end portions 6b. May be thicker than. In the transverse stretching step, the thickness T6b of both end portions 6b of the first resin film 6 (stretched film) becomes larger than the thickness T6a of the central portion 6a, and wrinkles toward the central portion 6a and wrinkles from the central portion 6a toward both end portions 6b occur. Even if it becomes easier, in the transporting process, the contact region 1a of the first roll 1 pushes wrinkles toward the central portion 6a of the first resin film 6 (stretched film) and wrinkles from the central portion 6a toward both end portions 6b. It can be expanded and resolved.

As shown in FIG. 6, the width W1a of the contact region 1a in contact with the first resin film 6 (stretched film) on the surface of the first roll 1 is narrower than the width W6 of the first resin film 6 (stretched film). good. When the width W1a of the contact region 1a of the first roll 1 is narrower than the width W6 of the first resin film 6 (stretched film), the contact region 1a of the first roll 1 is formed at both ends of the first resin film 6 (stretched film). It is difficult to hit the portion 6b (a portion thicker than the central portion 6a), and the first roll 1 tends to apply tension only to the central portion 6a of the first resin film 6 (stretched film). By applying tension only to the central portion 6a of the first resin film 6 (stretched film), wrinkles toward the central portion 6a of the first resin film 6 (stretched film) and wrinkles from the central portion 6a toward both end portions 6b are formed. Easy to spread. The difference (W6-W1a) between the width W6 of the first resin film 6 (stretched film) and the width W1a of the contact region 1a of the first roll 1 may be, for example, about 10 to 300 mm.

As shown in FIG. 6, the width W8 of the second resin film 8 (protective film) may be narrower than the width W6 of the first resin film 6 (stretched film). However, the width W8 of the second resin film 8 (protective film) may be wider than the width W6 of the first resin film 6 (stretched film). As shown in FIG. 6, the width W8 of the second resin film 8 (protective film) may be narrower than the width W1a of the contact region 1a of the first roll 1. However, the width W8 of the second resin film 8 (protective film) may be wider than the width W1a of the contact region 1a of the first roll 1. As shown in FIG. 6, the width W6 of the first resin film 6 (stretched film) may be narrower than the width W2 of the second roll 2. It may be narrower than the width W8 of the second resin film 8 (protective film) and the width W2 of the second roll 2.

(Other embodiments)
Although the first embodiment and the second embodiment of the present invention have been described above, the present invention is not limited to the above embodiment.

The wrinkles of the resin film are not necessarily caused only by the lateral stretching of the extruded film. For example, in the extrusion molding process of a thermoplastic resin, when the molten resin discharged from the ejection port (lip) of the extrusion mold is cooled and solidified by, for example, a cooling roll to form a film, the edge of the extrusion film is affected by the neck-in effect. The portion tends to be thicker than the central portion of the extruded film. That is, both ends of the extruded film before lateral stretching tend to be thicker than the central portion of the extruded film. The present invention is also useful as a means for suppressing wrinkles in the extrusion film caused by this extrusion molding step. Not limited to this example, wrinkles of the resin film due to the difference in the thickness of the resin film can be suppressed by the present invention in various situations in the transportation of the resin film or the production of the laminated film. In the production of the laminated film, the method for transporting the resin film according to the present invention may be carried out a plurality of times.

The laminated film manufacturing apparatus according to the first embodiment and the second embodiment may further include a coating apparatus in addition to the resin film transporting apparatus. In the method for producing a laminated film according to the first embodiment and the second embodiment, the surface of the first resin film facing the second resin film or the surface of the first resin film is directed by using a coating device before the transfer step. An adhesive or an adhesive may be applied to at least one of the surfaces of the second resin film. In the subsequent transport step, the first resin film and the second resin film may be sandwiched between the first roll and the second roll by interposing an adhesive or an adhesive between the first resin film and the second resin film. .. That is, in the transport step, the first resin film and the second resin film may be bonded together via an adhesive or an adhesive. That is, the resin film transporting device may also have a function of bonding the resin films to each other.

At least one of the first resin film and the second resin film may be a self-adhesive film. For example, the protective film may have self-adhesiveness. For example, there is a protective film made of polyethylene-based resin or polypropylene-based resin. The adhesive surface of the self-adhesive film may be, for example, the surface of the first resin film facing the second resin film. Alternatively, the adhesive surface of the self-adhesive film may be the surface of the second resin film facing the first resin film. Both the surface of the first resin film facing the second resin film and the surface of the second resin film facing the first resin film may be adhesive surfaces. When at least one of the first resin film and the second resin film is a self-adhesive film, the first resin film and the second resin film are bonded together in the transport step without using an adhesive or an adhesive. can do.

For example, in the first embodiment and the second embodiment, the second roll 2 may also be a crown roll. In the first embodiment and the second embodiment, the width of the contact region of the first roll may be narrower than both the width of the first resin film and the width of the second resin film. In the first embodiment and the second embodiment, both ends of the second resin film are thicker than the central portion of the second resin film located between the both ends, and both ends of the first resin film are both ends. It may be thicker than the central part of the first resin film located between.

The first resin film is not limited to the protective film or the stretched film. The second resin film is also not limited to the protective film or the stretched film. The first resin film or the second resin film is selected from the group consisting of, for example, a reflective polarizing film, an antiglare film, a surface antireflection film, a reflection film, a transflective reflective film, a retardation film, and a viewing angle compensation film. It may be a kind. The laminated film is composed of, for example, a group consisting of a polarizer, a polarizer protective film, a partially reflective polarizing film, an antiglare film, a surface antireflection film, a reflection film, a transflective reflective film, a retardation film, and a viewing angle compensating film. It may be a laminated optical film comprising at least one selected.

Hereinafter, the contents of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Example 1)
In Example 1, the following longitudinal stretching step, transverse stretching step, and transporting step were carried out in this order.

In the longitudinal stretching step, the long strip-shaped resin film was heated at 120 ° C., and the resin film was stretched in the long direction (transportation direction). As the resin film, a film formed of PMMA resin (methyl methacrylate / methyl acrylate copolymer (weight ratio 94/6), glass transition temperature 108 ° C.) was used. _{The width W 0} of the resin film before longitudinal stretching was 1000 mm. _{The thickness T 0} of the resin film before longitudinal stretching was the value shown in Table 1 below. The longitudinal stretching ratio was adjusted to the values shown in Table 1 below. _{The thickness T 1} of the central portion in the width direction (short direction) of the resin film (longitudinal stretched film) after the longitudinal stretching was the value shown in Table 1 below.

In the transverse stretching step following the longitudinal stretching step, the tenter method was adopted. In the tenter method, a transverse stretching device provided with two rows of clips arranged along both ends of the longitudinally stretched film was used. Each of the two clip rows consisted of a plurality of clips. In the transverse stretching step, both ends of the longitudinally stretched film were gripped by a plurality of clips arranged along both ends of the longitudinally stretched film. The vertically stretched film gripped by each clip was stretched in the width direction (horizontal direction) of the vertically stretched film by increasing the distance between the pair of clips facing each other in the width direction of the vertically stretched film while heating at 120 ° C. While heating the stretched film at the same temperature, relaxation was performed to narrow the distance between the clips by 5 mm. By the above procedure, a transversely stretched film (second resin film) was obtained. The transverse stretching ratio was adjusted to the value shown in Table 1 below. As shown in FIG. 4, both end portions 8b of the obtained transversely stretched film 8 in the width direction (short direction) were thicker than the central portion 8a of the transversely stretched film 8. That is, in both end portions 8b of the transversely stretched film 8, it is generally part having the same thickness as the thickness T ₁ of the longitudinally stretched film was left. The thickness T8a of the central portion 8a of the transversely stretched film 8 was a value shown in Table 1 below, and was substantially uniform.

This transversely stretched film was conveyed to the conveying device by a plurality of guide rolls. As shown in FIGS. 1 and 5, the transport device used in the first embodiment includes a first roll 1 and a second roll 2 arranged in parallel, and a motor for driving their rotation. The first roll 1 and the second roll 2 were nip rolls, and the first roll 1 was a crown roll whose surface was made of rubber. The maximum diameter of the contact region 1a of the first roll 1 (crown roll) was 120 mm. The crown amount of the first roll 1 was 400 μm. The width W1a of the contact region 1a of the first roll 1 was 1500 mm. The second roll 2 was a flat roll made of a rigid metal. The diameter of the second roll 2 was 210 mm. The width W2 of the second roll 2 was 2100 mm. In the transfer step, as shown in FIG. 1, the protective film 6 and the transversely stretched film 8 were brought into the space between the first roll 1 and the second roll 2 from the first roll 1 side, and these were conveyed in an overlapping state. .. As the protective film 6 (first resin film), a long strip-shaped film (“Tretec” manufactured by Toray Film Processing Co., Ltd.) formed from a polyethylene-based resin was used. The thickness of the protective film 6 was 30 μm. The width W6 of the protective film 6 was 1450 mm. The width W6 of the protective film 6 was narrower than the width W1a of the contact region 1a of the first roll 1. The width W8a of the central portion 8a of the transversely stretched film 8 was wider than the width W6 of the protective film 6. The width W1a of the contact region 1a of the first roll 1 was narrower than the width W8a of the central portion 8a of the transversely stretched film 8. The width W2 of the contact region of the second roll 2 was wider than the width W8 of the transversely stretched film 8.

The protective film 6 and the transversely stretched film 8 that were unwound from between the first roll 1 and the second roll 2 in an overlapping state were observed. After the transfer step of Example 1, there were no wrinkles in the transversely stretched film 8.

(Example 2)
In the longitudinal stretching step of Example 2, the thickness T ₀ of the resin film before the longitudinal stretching was the value shown in Table 1 below. In the longitudinal stretching step of Example 2, the longitudinal stretching ratio was adjusted to the values shown in Table 1 below. _{In the case of Example 2, the thickness T 1} of the central portion in the width direction of the longitudinally stretched film was the value shown in Table 1 below.

In the transverse stretching step of Example 2, the transverse stretching ratio was adjusted to the values shown in Table 1 below. Further, in the transverse stretching step of Example 2, relaxation was performed to narrow the interval between the clips by 10 mm. In the case of Example 2, the thickness T8a of the central portion 8a in the width direction of the obtained transversely stretched film 8 was the value shown in Table 1 below. In the case of Example 2, the width W8a of the central portion 8a of the transversely stretched film 8 was the value shown in Table 1 below.

In the case of Example 2, the width W6 of the protective film 6 was 1450 mm, and the width W6 of the protective film 6 was narrower than the width W1a of the contact region 1a of the first roll 1.

Except for the above items, the longitudinal stretching step, the transverse stretching step, and the transporting step of Example 2 were carried out in the same manner as in the case of Example 1. Even after the transfer step of Example 2, there were no wrinkles in the transversely stretched film.

(Example 3)
In the longitudinal stretching step of Example 3, the longitudinal stretching ratio was adjusted to the values shown in Table 1 below. _{In the case of Example 3, the thickness T 1} of the central portion in the width direction of the longitudinally stretched film was the value shown in Table 1 below.

In the transverse stretching step of Example 3, the transverse stretching ratio was adjusted to the values shown in Table 1 below. Further, in the transverse stretching step of Example 3, relaxation was performed to narrow the interval between the clips by 10 mm. In the case of Example 3, the thickness T8a of the central portion 8a in the width direction of the obtained transversely stretched film was the value shown in Table 1 below. In the case of Example 3, the width W8a of the central portion 8a of the transversely stretched film was the value shown in Table 1 below.

Except for the above items, the longitudinal stretching step, the transverse stretching step, and the transporting step of Example 3 were carried out in the same manner as in the case of Example 2. Even after the transfer step of Example 3, there were no wrinkles in the transversely stretched film.

(Comparative Example 1)
In the longitudinal stretching step of Comparative Example 1, the longitudinal stretching ratio was adjusted to the values shown in Table 1 below. _{In the case of Comparative Example 1, the thickness T 1} of the central portion in the width direction of the vertically stretched film was the value shown in Table 1 below.

In the transverse stretching step of Comparative Example 1, the transverse stretching ratio was adjusted to the values shown in Table 1 below. Further, in the lateral stretching step of Comparative Example 1, relaxation was performed in which the interval between the clips was narrowed by 16 mm. In the case of Comparative Example 1, the thickness T6a of the central portion 6a in the width direction of the obtained transversely stretched film was the value shown in Table 1 below. In the case of Comparative Example 1, the width W6a of the central portion 6a of the stretched film was the value shown in Table 1 below.

As shown in FIG. 8, in the transfer step of Comparative Example 1, a flat roll 10 made of rubber was used as the first roll instead of the crown roll. The diameter of the flat roll 10 of Comparative Example 1 was 160 mm. In the transfer step of Comparative Example 1, the approach angle of the first resin film 6 (stretched film) with respect to the flat roll 10 and the second roll 2 was zero. Further, in the transfer step of Comparative Example 1, the second resin film 8 (protective film) was allowed to enter between the flat roll 10 and the second roll 2 from the second roll 2 side. As shown in FIG. 8, the vertical relationship between the stretched film and the protective film in Comparative Example 1 was opposite to that in Example 1.

In the case of Comparative Example 1, the width W8 of the second resin film 8 (protective film) was 1900 mm. In the case of Comparative Example 1, the width W6 of the first resin film 6 (stretched film) was narrower than the width W8 of the second resin film 8 (protective film). In the case of Comparative Example 1, the width W6 of the first resin film 6 (stretched film) was narrower than the width of the first roll (flat roll 10) and the width W2 of the second roll 2. In the case of Comparative Example 1, the width W8 of the second resin film 8 (protective film) was also narrower than the width of the first roll (flat roll 10) and the width W2 of the second roll 2.

Except for the above items, the longitudinal stretching step, the transverse stretching step, and the transporting step of Comparative Example 1 were carried out in the same manner as in the case of Example 1. After the transfer step of Comparative Example 1, wrinkles were generated in the transversely stretched film 8.

(Comparative Example 2)
In the longitudinal stretching step of Comparative Example 2, the longitudinal stretching ratio was adjusted to the values shown in Table 1 below. _{In the case of Comparative Example 2, the thickness T 1} of the central portion in the width direction of the vertically stretched film was the value shown in Table 1 below.

In the transverse stretching step of Comparative Example 2, relaxation was not performed to narrow the interval between the clips. The transverse stretching ratio was adjusted to the value shown in Table 1 below. In the case of Comparative Example 2, the thickness T8a of the central portion 8a in the width direction of the obtained transversely stretched film 8 was the value shown in Table 1 below. In the case of Comparative Example 2, the width W8a of the central portion 8a of the stretched film was the value shown in Table 1 below.

The width W1 of the entire first roll 1 (crown roll) used in the transfer step of Comparative Example 2 was 2100 mm. The width W1a of the contact region 1a of the first roll 1 (crown roll) of Comparative Example 2 was 1591 mm. The crown amount of the first roll 1 of Comparative Example 2 was 1200 μm. As shown in FIG. 9, in the transport step of Comparative Example 2, the transversely stretched film 8 was allowed to enter between the first roll 1 and the second roll 2 from the second roll 2 side.

In the case of Comparative Example 2, the width W6 of the protective film 6 was 1800 mm. That is, in the case of Comparative Example 2, the width W6 of the protective film 6 was wider than the width W8 of the transversely stretched film 8. In the case of Comparative Example 2, the width W6 of the protective film 6 was wider than the width W1a of the contact region 1a of the first roll 1. In the case of Comparative Example 2, the width W1a of the contact region 1a of the first roll 1 was narrower than the width W8 of the transversely stretched film 8.

Except for the above items, the longitudinal stretching step, the transverse stretching step, and the transporting step of Comparative Example 2 were carried out in the same manner as in the case of Example 1. After the transfer step of Comparative Example 2, there were no wrinkles in the central portion of the transversely stretched film 8, but wrinkles were generated at both ends of the transversely stretched film 8.

(Comparative Example 3)
In the transverse stretching step of Comparative Example 3, relaxation was performed to narrow the distance between the clips by 5 mm. The thickness T8a of the central portion 8a in the width direction of the obtained transversely stretched film 8 was the value shown in Table 1 below. In the case of Comparative Example 3, the width W8a of the central portion 8a of the transversely stretched film 8 was the value shown in Table 1 below.

In the transfer step of Comparative Example 3, the transversely stretched film 8 was allowed to enter between the first roll 1 and the second roll 2 from the second roll 2 side.

Except for the above items, the longitudinal stretching step, the transverse stretching step, and the transporting step of Comparative Example 3 were carried out in the same manner as in the case of Example 1. After the transfer step of Comparative Example 3, the laterally stretched film 8 was slightly wrinkled.

According to the method for transporting a resin film according to the present invention, wrinkles in the stretched film can be suppressed when the stretched film (for example, a polarizer film) is transported in the manufacturing process of the laminated film (for example, a laminated polarizing plate).

1 ... 1st roll (crown roll), 1a ... contact area of 1st roll, 2 ... second roll, 4 ... laminated film, 6 ... first resin film (protective film of the first embodiment, second embodiment) Transversely stretched film), 8 ... Second resin film (transversely stretched film of the first embodiment, protective film of the second embodiment), 8a ... Central portion of the second resin film, 8b ... Both ends of the second resin film, 100 ... Resin film transport device, W1a ... Width of contact area of first roll, W6 ... Width of first resin film, W8 ... Width of second resin film.

Claims (17)

A step of sandwiching and transporting the first resin film and the second resin film between the first roll and the second roll in a state of being overlapped with each other is provided.
The first roll is a crown roll,
The first resin film and the second resin film are allowed to enter between the first roll and the second roll from the first roll side.
In a cross section perpendicular to the rotation axis A1 of the first roll and the rotation axis A2 of the second roll, the first reference line L1 is perpendicular to the line segment La connecting the rotation axis A1 and the rotation axis A2. And it is a line segment that intersects with the first resin film.
In the cross section, the approach angle θ1 of the first resin film is defined as the angle formed by the first resin film with respect to the first reference line L1.
In the cross section, the second reference line L2 is a line segment that is perpendicular to the line segment La and intersects with the second resin film.
In the cross section, the approach angle θ2 of the second resin film is defined as the angle formed by the second resin film with respect to the second reference line L2.
The approach angle θ1 is 10 to 170 °.
The approach angle θ2 is 10 to 170 °.
Method of transporting resin film. At least one of both ends of the second resin film in a direction perpendicular to the transport direction of the second resin film before the second resin film enters between the first roll and the second roll. Is thicker than the central portion of the second resin film located between the both ends of the
The method for transporting a resin film according to claim 1. The width of the contact region in contact with the first resin film on the surface of the first roll is narrower than the width of the second resin film in contact with the second roll.
The method for transporting a resin film according to claim 1 or 2. At least one of both ends of the first resin film in a direction perpendicular to the transport direction of the first resin film before the first resin film enters between the first roll and the second roll. Is thicker than the central portion of the first resin film located between the both ends of the
The method for transporting a resin film according to any one of claims 1 to 3. The width of the contact region in contact with the first resin film on the surface of the first roll is narrower than the width of the first resin film.
The method for transporting a resin film according to any one of claims 1 to 4. The entire surface of the first resin film is brought into contact with the surface of the first roll.
The method for transporting a resin film according to any one of claims 1 to 4. It is a method of manufacturing a laminated film in which a first resin film and a second resin film are laminated.
The first resin film and the second resin film are sandwiched between the first roll and the second roll in a state of being overlapped with each other and conveyed.
The first roll is a crown roll,
In the transfer step, the first resin film and the second resin film are allowed to enter between the first roll and the second roll from the first roll side.
In a cross section perpendicular to the rotation axis A1 of the first roll and the rotation axis A2 of the second roll, the first reference line L1 is perpendicular to the line segment La connecting the rotation axis A1 and the rotation axis A2. And it is a line segment that intersects with the first resin film.
In the cross section, the approach angle θ1 of the first resin film is defined as the angle formed by the first resin film with respect to the first reference line L1.
In the cross section, the second reference line L2 is a line segment that is perpendicular to the line segment La and intersects with the second resin film.
In the cross section, the approach angle θ2 of the second resin film is defined as the angle formed by the second resin film with respect to the second reference line L2.
The approach angle θ1 is 10 to 170 °.
The approach angle θ2 is 10 to 170 °.
A method for manufacturing a laminated film. At least one of both ends of the second resin film in a direction perpendicular to the transport direction of the second resin film before the second resin film enters between the first roll and the second roll. Is thicker than the central portion of the second resin film located between the both ends of the
The method for producing a laminated film according to claim 7. The width of the contact region in contact with the first resin film on the surface of the first roll is narrower than the width of the second resin film in contact with the second roll.
The method for producing a laminated film according to claim 7 or 8. At least one of both ends of the first resin film in a direction perpendicular to the transport direction of the first resin film before the first resin film enters between the first roll and the second roll. Is thicker than the central portion of the first resin film located between the both ends of the
The method for producing a laminated film according to any one of claims 7 to 9. The width of the contact region in contact with the first resin film on the surface of the first roll is narrower than the width of the first resin film.
The method for producing a laminated film according to any one of claims 7 to 10. The entire surface of the first resin film is brought into contact with the surface of the first roll.
The method for producing a laminated film according to any one of claims 7 to 10. In the transfer process,
An adhesive or an adhesive is interposed between the first resin film and the second resin film.
By sandwiching the first resin film and the second resin film between the first roll and the second roll, the first resin film and the second resin film are bonded together.
The method for producing a laminated film according to any one of claims 7 to 12. At least one of the first resin film and the second resin film is a self-adhesive film.
The method for producing a laminated film according to any one of claims 7 to 12. It is provided with a first roll and a second roll that sandwich and convey the first resin film and the second resin film in a state of being overlapped with each other.
The first roll is a crown roll,
The first resin film and the second resin film are configured to enter between the first roll and the second roll from the first roll side .
Used in the method for transporting a resin film according to any one of claims 1 to 6.
Resin film transfer device. A device for manufacturing a laminated film in which a first resin film and a second resin film are laminated.
The transport device according to claim 15 is provided.
Laminated film manufacturing equipment. A coating device for applying an adhesive or an adhesive to at least one surface of the first resin film facing the second resin film or the surface of the second resin film facing the first resin film is further provided. Prepare, prepare
The apparatus for producing a laminated film according to claim 16.

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