TWI733913B - Method for transporting resin film - Google Patents

Abstract

An object of the present invention is to provide a method for transporting resin film capable of suppressing wrinkling of resin film.

The method for transporting resin film of the present invention including a step of gripping and conveying a first resin film 6 and a second resin film 8 by a first roller 1 and a second roller 2 in a state of the first resin film 6 and the second resin film 8 being overlapped with each other, wherein the first roller 1 is a crown roller, and the first resin film 6 and the second resin film 8 are rendered to enter into between the first roller 1 and the second roller 2 from the first roller 1 side.

Description

How to transport the resin film

The present invention relates to a transportation method of a resin film, and also relates to a manufacturing method of a laminated film, a transportation device of a resin film, and a manufacturing device of a laminated film.

In image display devices that use optical display devices such as liquid crystal display elements or EL elements such as organic electroluminescence (OLED) elements, optical compensation films (phase difference films), protective films, and anti-reflection films are used. membrane.

In the production of this 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. Sometimes the resin film is further stretched in the width direction (lateral direction). By this transverse stretching, desired optical properties or toughness are imparted to the resin film. Specifically, while continuously conveying the long strip-shaped thermoplastic resin film in the longitudinal direction, both ends of the resin film are held with clamps. Then by expanding the distance between the clamps, the resin film is stretched in the width direction. Then, a laminated film (a laminated optical film) is completed through a step of laminating the stretched resin film and another resin film (for example, a protective film, etc.).

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2010-36414 A.

Both ends of the resin film held by the clamps in the lateral stretching remain almost the same thickness as the thermoplastic resin film before stretching. On the other hand, the part between the two ends becomes thinner by 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 resin film adjusted to a predetermined width is usually shipped as a product after being wound into a roll.

As described above, since there is a difference in thickness between the both end portions and the center portion of the stretched film, wrinkles are likely to be generated in the stretched film during transportation before the slitting process. Before the slitting process, when wrinkles are generated near both ends of the stretched film, defects are likely to occur during slitting. In addition, there may be cases where the film (powder) caused by poor slitting is mixed into the finished product. Furthermore, the wrinkles of the stretched film are also the cause of impairing the uniformity of the optical properties of the optical film. Especially when the resin film is made of relatively brittle and easily broken thermoplastic resins such as polymethyl methacrylate (PMMA: Polymethyl Methacrylate) or polystyrene (PS: Polystyrene), it is caused by the production before the slitting process. The wrinkles not only easily cause the film mixing caused by poor slitting, but also cause the stretched film to break.

The above-mentioned wrinkles of the resin film are not necessarily caused only by lateral stretching. For example, in the extrusion molding of thermoplastic resin, the resin film ejected from the ejection port (pouring nozzle) of the extrusion die is easily affected by the neck-in during ejection. Becomes thicker than the ends. That is, in the extrusion molding of the resin, both end portions of the resin film tend to become thicker than the center portion of the resin film. It is not limited to this example. In various steps in the transportation of the resin film or the production of the laminated film, a technique for suppressing the wrinkles of the resin film caused by the difference in the thickness of the resin film is necessary.

The present invention was created in view of the above-mentioned problems of the prior art, and the object is to provide a resin film transport method, a laminate film manufacturing method, a resin film transport device, and a laminate film manufacturing method that can suppress wrinkles of the resin film Device.

One aspect of the present invention is a method for transporting a resin film that includes a step of sandwiching and transporting a first resin film and a second resin film while being overlapped with each other by a first roller and a second roller; wherein, the first The roll is a crown roll, and the first resin film and the second resin film enter between the first roll and the second roll from the side of the first roll.

In one aspect of the method of conveying the resin film facing the present invention, the second resin in the direction perpendicular to the conveying direction of the second resin film before the second resin film enters between the first roller and the second roller At least one of the two ends of the film may be thicker than the central portion of the second resin film located between the two ends.

The term "both ends of the second resin film" refers to both ends of the second resin film in a direction perpendicular to the conveying direction of the second resin film. The "two ends of the second resin film" can be changed to the two ends of the second resin film in a direction parallel to the axis of rotation of the second roller. The "two ends of the second resin film" can also be changed to the two ends of the second resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped second resin film. The conveying direction of the second resin film can be changed to the longitudinal direction of the second resin film.

In one aspect of the face-to-face resin film transport method of the present invention, in the surface of the first roller, the width of the contact area in contact with the first resin film may be narrower than the width of the second resin film in contact with the second roller.

The "width of the contact area" of the first roller is the width of the contact area of the first roller in the direction perpendicular to the conveying direction of the first resin film. The "width of the contact area" of the first roller can be changed to the width of the contact area of the first roller in a direction parallel to the rotation axis of the first roller. The "width of the contact area" of the first roller can also be changed to the width of the contact area of the first roller in the direction perpendicular to the longitudinal direction of the long strip-shaped first resin film. The conveying direction of the first resin film may be changed to the longitudinal direction of the first resin film.

The "width of the second resin film" refers to the width of the second resin film in a direction perpendicular to the conveying direction of the second resin film. The "width of the second resin film" can be changed to the width of the second resin film in a direction parallel to the rotation axis of the second roller. The "width of the second resin film" can also be changed to the width of the second resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped second resin film.

In one aspect of the method of conveying the resin film facing the present invention, the first resin in the direction perpendicular to the conveying direction of the first resin film before the first resin film enters between the first roller and the second roller At least one of the two ends of the film may be thicker than the central portion of the first resin film located between the two ends.

The term "both ends of the first resin film" refers to both ends of the first resin film in a direction perpendicular to the conveying direction of the first resin film. The "both ends of the first resin film" may be renamed as the both ends of the first resin film in a direction parallel to the rotation axis of the first roller. The "both ends of the first resin film" may also be renamed as the both ends of the first resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped first resin film. The conveying direction of the first resin film may be changed to the longitudinal direction of the first resin film.

In one aspect of the face-to-face resin film transport method of the present invention, in the surface of the first roller, the width of the contact area in contact with the first resin film may be narrower than the width of the first resin film.

The "width of the first resin film" refers to the width of the first resin film in a direction perpendicular to the conveying direction of the first resin film. The "width of the first resin film" can be changed to the width of the first resin film in a direction parallel to the rotation axis of the first roller. The "width of the first resin film" can also be changed to the width of the first resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped first resin film.

In one aspect of the resin film transport method of the present invention, the entire surface of the first resin film can be in contact with the surface of the first roller.

One aspect of the present invention is a method for manufacturing a laminated film that is a method of manufacturing a laminated film in which a first resin film and a second resin film are laminated, and includes: the first resin film and the second resin film are overlapped with each other The step of nipping and conveying by the first roller and the second roller; wherein the first roller is a crowned roller, and the first resin film and the second resin film enter between the first roller and the second roller from the side of the first roller .

In the manufacturing method of the laminated film facing one aspect of the present invention, the second resin in the direction perpendicular to the conveying direction of the second resin film before the second resin film enters between the first roller and the second roller At least one of the two ends of the film may be thicker than the central portion of the second resin film located between the two ends.

In one aspect of the method for manufacturing a laminated film facing the present invention, in the surface of the first roll, the width of the contact area in contact with the first resin film may be narrower than the width of the second resin film in contact with the second roll.

In one aspect of the manufacturing method of the laminated film facing the present invention, the first resin in the direction perpendicular to the conveying direction of the first resin film before the first resin film enters between the first roller and the second roller At least one of the two ends of the film may be thicker than the central portion of the first resin film located between the two ends.

In the manufacturing method of the facing laminated film of the aspect of the present invention, in the surface of the first roll, the width of the contact area in contact with the first resin film may be narrower than the width of the first resin film.

In the manufacturing method of the laminated film facing one aspect of the present invention, the entire surface of the first resin film can be in contact with the surface of the first roll.

In the manufacturing method of the laminated film facing one aspect of the present invention, in the conveying step: an adhesive or an adhesive can be interposed between the first resin film and the second resin film, and the first roller and the second roller By holding the first resin film and the second resin film, the first resin film and the second resin film are bonded together.

In the manufacturing method of the laminated film which is 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.

One aspect of the present invention is a resin film conveying device that includes: a first roller and a second roller that sandwich and convey the first resin film and the second resin film while overlapping each other; and the conveying device is configured The first roller is a crown roller; the first resin film and the second resin film enter between the first roller and the second roller from the side of the first roller.

One aspect of the present invention is a manufacturing apparatus for a laminated film that is used for manufacturing a laminated film of a first resin film and a second resin film, and is provided with the aforementioned conveying device.

One aspect of the present invention is a laminated film manufacturing apparatus further equipped with: applying an adhesive or adhesive to the surface of the first resin film facing the second resin film, or the surface of the second resin film facing the first resin film At least any side of the coating device.

According to the present invention, there is provided a resin film conveying method, a laminated film manufacturing method, a resin film conveying device, and a laminated film manufacturing device that can suppress wrinkles of the resin film.

1‧‧‧The first roller (crown roller)

1a‧‧‧Contact area

1b‧‧‧ Both ends

2‧‧‧The second roll

4‧‧‧Laminated film

6‧‧‧The first resin film (protective film, stretch film)

8‧‧‧Second resin film (stretch film, protective film)

8a‧‧‧Central part

8b‧‧‧ Both ends

100‧‧‧Resin film conveying device

A1, A2‧‧‧axis of rotation

D6, D8‧‧‧Conveying direction

L1‧‧‧First Baseline

L2‧‧‧Second Baseline

La‧‧‧line segment

T6a, T6b‧‧‧Thickness

T8a, T8b‧‧‧Thickness

W1a‧‧‧Width

W6‧‧‧Width

W6a‧‧‧Width

W8‧‧‧Width

W8a‧‧‧Width

θ 1, θ 2‧‧‧Entry angle

Fig. 1 is a schematic diagram of a resin film conveying device and a conveying method according to the first embodiment of the present invention, which shows the case where the entrance angle θ1 of the first resin film is an obtuse angle.

Fig. 2 is a modified example of the conveying device and conveying method shown in Fig. 1, which shows the case where the entry angle θ1 of the first resin film is an acute angle.

Fig. 3 is a schematic view of the cross section of the conveying device, the first resin film and the second resin film shown in Fig. 1, which shows a cross section including the rotation axis of the first roller and the rotation axis of the second roller.

Fig. 4 is a schematic enlarged view of the cross-section of the second resin film (stretched film) before the transport step of the first embodiment.

Fig. 5 is a modified example of the cross section shown in Fig. 3, which shows that the entire surface of the first resin film is in close contact with the surface (contact area) of the first roller.

Fig. 6 is a schematic cross-sectional view of a resin film conveying device, a first resin film, and a second resin film according to the second embodiment of the present invention.

Fig. 7 is a schematic enlarged view of the cross section of the first resin film (stretched film) before the transport step of the second embodiment.

Fig. 8 is a schematic diagram of the conveying device and the conveying method of the resin film of Comparative Example 1.

Fig. 9 is a schematic diagram of a conveying device and a conveying method of the resin film of Comparative Example 2.

The following is a description of the preferred embodiments of the present invention with reference to the drawings. In the drawings, the same symbols are attached to the same constituent elements. 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 directions shown by each coordinate axis are common in all figures.

(First Embodiment)

The first embodiment of the present invention relates to a manufacturing method and manufacturing apparatus of a laminated film in which a protective film and a stretched film are laminated. In addition, the first embodiment relates to a conveying method and a conveying device of the protective film and the stretched film. In the first embodiment, the first resin film is a protective film. However, as described later, the first resin film may not be a protective film. In the first embodiment, the second resin film is a thermoplastic stretched film. The stretched film is, for example, a resin film imparted with desired characteristics such as optical properties and toughness by applying either or both of longitudinal stretching and lateral 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 may not have thermoplasticity, or may not be a stretched film. In the following, a laminate including a protective film and a stretched film superimposed directly or indirectly is referred to as a laminate film. The first resin film may be a single-layer film with a single-layer structure or a multilayer film with a multi-layer structure. In addition, the second resin film may be a single-layer film with a single-layer structure or a multilayer film with a multi-layer structure. The first resin film and the second resin film may both be single-layer films or both may be multilayer films. The first resin film may be a single-layer film and the second resin film may be a multilayer film. Alternatively, 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 any thermoplastic resin having translucency, and preferably any thermoplastic resin that is optically transparent. The thermoplastic resin may be, for example, a polyolefin resin such as a chain polyolefin resin, a cyclic polyolefin resin (for example, a norbornene resin), a polyethylene resin, or a polypropylene resin. The thermoplastic resin may also be a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, or poly-L-lactic acid. The thermoplastic resin may also be a (meth)acrylic resin such as methyl methacrylate resin. The thermoplastic resin may also be a cellulose resin such as cellulose triacetate or cellulose diacetate. The thermoplastic resin may also be a polycarbonate resin, a polyvinyl alcohol resin, a polyvinyl acetate resin, a polyarylate resin, a polystyrene resin, a polyether ether resin, a polyvinyl alcohol resin, and a polyamide resin. Based resin, or polyimide based resin. The thermoplastic resin may be a mixture or copolymer of the above-mentioned resins. The thermoplastic resin may contain inorganic substances within the range that does not impair the light transmittance. The thermoplastic resin may further contain additives if necessary. The additives may be, for example, antioxidants, ultraviolet absorbing materials, antistatic agents, lubricants, nucleating agents, anti-fogging agents, or anti-caking agents. For example, when producing a polarizer as a stretched film, the thermoplastic resin may be a polyvinyl alcohol-based resin.

The resin constituting the protective film may be polyethylene resin, polypropylene resin, or polyester resin (for example, polyethylene terephthalate). On the surface of the protective film opposite to the stretched film, an adhesive layer can be formed.

The stretched film is produced through, for example, the extrusion molding step, the longitudinal stretching step, and the transverse stretching step described below. The stretched film can be made after the longitudinal stretching step and then the transverse stretching step, or the transverse stretching step and then the longitudinal stretching step can be made to make the stretched film. In addition, it is also possible to make a stretched film after going through the extrusion forming step and then going through the transverse stretching step. The following describes the case where the transverse stretching step is performed after the longitudinal stretching step.

In the extrusion step, the heated and melted thermoplastic resin is continuously extruded from a discharge port (pouring nozzle) provided at the front end of the extruder to be molded into a film shape. The molded body is cooled by passing through a plurality of cooling rolls, thereby obtaining a long strip-shaped extruded film. The extruded film can be directly and continuously transported to the longitudinal stretching device. Or, after the extruded film is wound into a roll shape, the roll-shaped extruded film is pulled out and transported to the longitudinal stretching device. The extruded film is conveyed along its longitudinal direction.

The longitudinal stretching device is provided with at least two rolls separated and arranged, for example. The so-called roll is a device that is composed of a pair of rolls, and the resin film is sandwiched between the pair of rolls and conveyed while pressing. In the longitudinal stretching step, the extruded film passes through two rolls provided in the longitudinal stretching device. The peripheral speed of the roll that initially passes the extruded film is adjusted to be slower than the peripheral speed of the roll that subsequently passes the extruded film. With 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 can be arranged between the two rolls, and the extruded film can be heated while stretching. Before the longitudinal stretching step, the extruded film can be preheated.

The longitudinal stretching step is followed by a transverse stretching step. The tentering method will be described below as an example of the transverse stretching step. The transverse stretching device used in the tenter method includes, for example, two clamp rows arranged along both ends of the longitudinally stretched film. That is, the longitudinally stretched film is arranged between two clamp rows. Each clamp row is composed of a plurality of clamps. That is, a plurality of clamps are arranged along both ends of the stretched film in the longitudinal direction. Hold both ends of the longitudinally stretched film with each clamp. In the horizontal stretching step, the longitudinally stretched film whose two ends have been gripped by a plurality of clamps is conveyed in the longitudinal direction. During the conveying process, the longitudinally stretched film becomes a transversely stretched film by expanding the interval between a pair of clamps in the opposite direction in the width direction (lateral direction) of the longitudinally stretched film. After expanding the gap between a pair of clamps, an operation to slightly narrow the gap (so-called loosening) can be performed. Then the two ends of the transversely stretched film are released from the clamp. Release the pair of clamps after the transversely stretched film, return to the upstream side and hold both ends of the longitudinally stretched film again. That is, a plurality of clamps are repeated: the holding of both ends of the longitudinally stretched film, the lateral stretch of the longitudinally stretched film, and the release of the laterally stretched film. By the above tenter method, the longitudinally stretched film is continuously stretched in the width direction (lateral direction) to obtain a laterally stretched film. In the transverse stretching step, the longitudinally stretched film can also be stretched while heating. In the transverse stretching step or after the transverse stretching step, heat curing for stabilizing the transverse stretch by heating the film can be performed. The stretched film after lateral stretching is guided by a plurality of guide rollers, and is conveyed to a conveying device described later.

The thickness of the two ends of the longitudinally stretched film held by the clamp is almost the same after the transverse stretch as before the transverse stretch. On the other hand, the part (central part) located between the two ends of the longitudinally stretched film tends to be thinned by lateral stretching. That is, as shown in FIG. 4, the both end portions 8b of the laterally stretched film 8 are easier to thicken than the central portion 8a of the laterally stretched film 8 located between the two end portions 8b. The thickness T8a of the central portion 8a of the transversely stretched film 8 is easily uniform. Therefore, both ends 8b of the laterally stretched film 8 are cut/removed by the subsequent slitting process, and the width W8 of the laterally stretched film 8 is adjusted to a predetermined width (for example, the width W8a). However, when the laterally stretched film 8 is conveyed to the slitting device by a conventional conveying method using guide rolls or nip rolls, the laterally stretched film 8 during conveyance is likely to be wrinkled. Particularly, in the transversely stretched film 8, wrinkles from the both end portions 8b to the center portion 8a, or wrinkles from the center portion 8a to the end portions 8b are likely to occur. This wrinkle is caused by the difference between the thickness T8b of the both end portions 8b of the transversely stretched film 8 and the thickness T8a of the central portion 8a. According to the conveying device and the conveying method described in detail below, wrinkles of the laterally stretched film 8 (second resin film) during conveyance can be suppressed. However, the wrinkles of the stretched film during transportation are not necessarily due to the difference in thickness. Even in the case where there is almost no difference in thickness of the laterally stretched film 8, according to the conveying device and the conveying method of the first embodiment, wrinkles of the laterally stretched film 8 during conveyance can be suppressed.

The manufacturing apparatus of the laminated film of the first embodiment, as shown in FIGS. 1 to 3, is provided with a conveying device 100 that conveys the protective film 6 and the laterally stretched film 8. The conveying device 100 includes a first roller 1 and a second roller 2. The rotation axis A1 of the first roller 1 is parallel to the rotation axis A2 of the second roller 2. In the conveying step, the protective film 6 and the laterally stretched film 8 are sandwiched by the first roller 1 and the second roller 2 in a state where they overlap each other and are conveyed. The protective film 6 is also in the shape of a long strip like the transversely stretched film 8. The protective film 6 is drawn from, for example, a raw material roll and supplied to the conveying device 100.

The first roller 1 and the second roller 2 are rollers that apply linear pressure to the surface of the resin film. That is, the protective film 6 and the laterally stretched film 8 are sandwiched between the first roller 1 and the second roller 2 during the conveying process, and are pressed by the first roller 1 and the second roller 2. For example, by controlling the speed of the roll, the tension of each of the protective film 6 and the transverse stretch film 8 located on the upstream side of the roll can be controlled.

The first roller 1 is a crown roller. That is, as shown in FIG. 3, in the cross section including the rotation axis A1 of the first roller 1, the surface of the contact area 1a located in the center of the first roller 1 has a gentle curve. In addition, the diameter (thickness) of the first roller 1 decreases from the center of the first roller 1 toward the both ends 1b of the first roller 1. On the other hand, the second roller 2 may, for example, have a flat roller having a substantially uniform diameter. That is, as shown in FIG. 3, in a cross section including the rotation axis A2 of the second roller 2, the surface of the second roller 2 is a straight line. In reality, however, the second roller 2 can flex along the contact area 1a of the first roller 1, for example due to its own weight.

The manufacturing method of the laminated film of 1st Embodiment is equipped with the conveyance process using the conveyance apparatus 100. As shown in FIG. In the conveying step, the protective film 6 and the laterally stretched film 8 are brought into between the first roller 1 and the second roller 2 from the side of the first roller 1. That is, the protective film 6 and the laterally stretched film 8 are made to enter between the rolls from the side of the crown roll. As a result, the first roller 1 easily imparts linear pressure to the protective film 6 and the laterally stretched film 8. Furthermore, the contact area 1a of the first roller 1 (the thicker part of the crown roller) is convex compared to the flat roller, so it is easy to contact the surface of the protective film 6. Due to the entry direction of each resin film and the shape of the first roll 1 (crown roll) as described above, the first roll 1 can apply sufficient linear pressure to the central portion 8a of the transversely stretched film 8 via the protective film 6. With the application of linear pressure, tension can be applied to the central portion 8a of the laterally stretched film 8 located on the upstream side of the conveying device 100, so that the laterally stretched film 8 is wrinkled toward the central portion 8a or from the central portion 8a toward both sides. The wrinkles at the end 8b are difficult to produce. In addition, even if wrinkles are generated in the transversely stretched film 8 located on the upstream side of the conveying device 100, the wrinkles of the transversely stretched film 8 are compressed and eliminated due to the shape of the first roller 1 (crown roller). By the above-mentioned 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 enters between the first roller 1 and the second roller 2 from the second roller 2 side, the contact area 1a of the first roller 1 (the first roller 1) It is difficult to apply linear pressure to the central portion 8a of the transversely stretched film 8, and it is difficult to suppress wrinkles. Moreover, even when the first roller 1 is a flat roller, it is difficult for the first roller 1 to apply linear pressure to the central portion 8a of the laterally stretched film 8, and it is difficult to suppress wrinkles.

As shown in Figures 1 and 2, on the cross section (ZX plane) perpendicular to the rotation axis A1 of the first roller 1 and the rotation axis A2 of the second roller 2, the first reference line L1 is connected to the connecting rotation axis A1 A line segment La perpendicular to the rotation axis A2 and a line segment intersecting the protective film 6 (first resin film). The entry angle θ1 of the protective film 6 (first resin film) is defined as the angle between the protective film 6 (first resin film) and the first reference line L1. In addition, on the cross section perpendicular to the rotation axis A1 and the rotation axis A2, the second reference line L2 is a line segment perpendicular to the line segment La and intersecting the transverse stretch film 8 (second resin film). The entry angle θ2 of the laterally stretched film 8 (second resin film) is defined as the included angle of the laterally stretched film 8 (second resin film) with respect to the second reference line L2.

As shown in Fig. 1, the entrance angle θ1 of the protective film 6 may be an obtuse angle. As shown in Fig. 2, the entrance angle θ1 of the protective film 6 may be an acute angle. The entrance angle θ1 of the protective film 6 may be, for example, 10 to 170°. In order to increase the effect of suppressing wrinkles due to the shape of the first roller 1, the entry angle θ1 is preferably 30 to 120°. As shown in Fig. 1, the entrance angle θ2 of the transversely stretched film 8 may be an acute angle. The entrance angle θ2 of the transversely stretched film 8 may be an obtuse angle. For example, the entry angle θ2 of the transversely stretched film 8 may be 10 to 170°. When the entry angles θ1 and θ2 are within the above range, wrinkles of the laterally stretched film 8 are easily suppressed.

At the point before the transversely stretched film 8 enters between the first roller 1 and the second roller 2, as shown in Figure 4, the transversely stretched film in the direction perpendicular to the conveying direction D8 of the transversely stretched film 8 The two end portions 8b of 8 may be thicker than the central portion 8a of the transversely stretched film 8 located between the two end portions 8b. That is, the two ends 8b of the transversely stretched film 8 in the width direction (short-side direction or the Y-axis direction) may be thicker than the central portion 8a of the transversely stretched film 8 located between the two ends 8b. In the lateral stretching step, even if the thickness T8b of the both ends 8b of the laterally stretched film 8 is greater than the thickness T8a of the central part 8a, wrinkles are likely to occur toward the central part 8a or from the central part 8a to the both ends 8b. However, in the conveying step, the contact area 1a of the first roller 1 can also uniformly apply tension to the central portion 8a of the transversely stretched film 8 through the protective film 6, so that the transversely stretched film 8 can be suppressed. Of the folds. In addition, even if wrinkles are generated in the transversely stretched film 8 located on the upstream side of the conveying device 100, the wrinkles of the transversely stretched film 8 are compressed and eliminated due to the shape of the first roller 1 (crown roller).

As shown in Figure 3, a part of the surface of the protective film 6 (first resin film) can be made to adhere to the surface of the first roller 1 (the contact area 1a of the first roller 1), or as shown in Figure 5. As shown, the entire surface of the protective film 6 (first resin film) is made to adhere to the surface of the first roller 1 (the contact area 1a of the first roller 1). The larger the surface area of the protective film 6 (first resin film) adhering to the surface of the first roller 1 (the contact area 1a of the first roller 1), the easier it is for the contact area 1a of the first roller 1 to pass through the protective film 6 (No. One resin film) applies linear pressure to the central portion 8a of the laterally stretched film 8 (second resin film). As a result, the wrinkles of the transversely stretched film 8 toward the center portion 8a or the wrinkles from the center portion 8a toward both end portions 8b hardly occur. In addition, even if wrinkles are generated in the laterally stretched film 8 located on the upstream side of the conveying device 100, the wrinkles of the laterally stretched film 8 are easily compressed due to the shape of the first roll 1 (crown roll).

On the surface of the first roller 1, the width W1a of the contact area 1a in contact with the protective film 6 (first resin film) may be narrower than the width W8 of the laterally stretched film 8 (second resin film) in contact with the second roller 2. When the width W1a of the contact area 1a of the first roller 1 is narrower than the width W8 of the laterally stretched film 8 (the second resin film), the contact area 1a of the first roller 1 hardly touches the laterally stretched film 8 ( On both ends 8b (thicker portions than the central portion 8a) of the second resin film), the first roller 1 can easily apply tension to only the central portion 8a of the laterally stretched film 8 (second resin film). Since tension is only applied to the central portion 8a of the laterally stretched film 8 (second resin film), it is difficult to cause wrinkles or wrinkles toward the central portion 8a of the laterally stretched film 8 (second resin film) or from the central portion 8a. Wrinkles at both ends 8b. In addition, even if wrinkles are generated in the transversely stretched film 8 located on the upstream side of the conveying device 100, the wrinkles of the transversely stretched film 8 are easily compressed due to the shape of the first roller 1 (crown roller). The difference (W8 minus W1a) between the width W8 of the laterally stretched film 8 (second resin film) and the width W1a of the contact area 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) can be narrower than the width W1a of the contact area 1a of the first roller 1. When the width W6 of the protective film 6 (first resin film) is narrower than the width W1a of the contact area 1a of the first roller 1, the contact area 1a of the first roller 1 can easily apply linear pressure to the protective film 6 and the laterally stretched film 8. However, the width W6 of the protective film 6 (the first resin film) may be wider than the width W1a of the contact area 1a of the first roller 1. As shown in Fig. 3, the width W6 of the protective film 6 (first resin film) can be narrower than the width W8 of the laterally 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 laterally stretched film 8 (second resin film). As shown in FIG. 3, the width W8 of the laterally stretched film 8 (the second resin film) can be narrower than the width W2 of the second roll 2.

As shown in Figure 3, in the conveying step, the central part of the first roller 1, the central part of the protective film 6 (first resin film), the central part of the laterally stretched film 8 (second resin film), and the second The central part of the two rollers 2 can be aligned on the same plane (ZX surface) or on the same straight line (Z axis).

The surface of the first roller 1 may be a rigid body with high rigidity. For example, the surface of the first roller 1 may be metal such as iron or stainless steel (SUS304). The surface of the first roller 1 may be an elastomer. For example, the surface of the first roller 1 may be rubber such as nitrile rubber (NBR: Nitrile Rubber), urethane rubber, silicone rubber, or ethylene-propylene-diene rubber (EPDM: Ethylene-Propylene-Diene Monomer). From the viewpoint of ease of imparting a crown shape, the surface of the first roller 1 is preferably an elastomer.

The surface of the second roller 2 may be a rigid body with high rigidity. For example, the surface of the second roller 2 may be metal such as iron or stainless steel (SUS304), and the surface of the second roller 2 may also be subjected to surface treatment such as chrome plating or nickel plating. The surface of the second roller 2 may be an elastic body. For example, the surface of the second roller 2 may be rubber such as nitrile rubber (NBR), urethane rubber, silicone rubber, or ethylene-propylene-diene rubber (EPDM).

One or both of the first roller 1 and the second roller 2 can be directly or indirectly driven to rotate by a power source (such as a motor).

From the viewpoint of having the effect of suppressing wrinkles and uniform bonding pressure, it is preferable that the surface of the first roller 1 is an elastic body, and the surface of the second roller 2 is a rigid body.

The protective film 6 and the laterally stretched film 8 are drawn out from between the first roll 1 and the second roll 2 in the form of a laminated film 4. The laminated film 4 is guided by a plurality of guide rollers, and is transported to the slitting processing device. In the slitting processing step using the slitting processing device, both ends 8b of the transversely stretched film 8 are cut (cut) and removed. When both end portions 8b of the laterally stretched film 8 overlap the protective film 6, a part of the protective film 6 overlapping the both end portions 8b of the laterally stretched film 8 is also cut (divided) and removed.

The laminated film 4 after the slitting process can be laminated or laminated with other resin films. For example, a protective film (second resin film) different from the protective film 6 may be laminated or bonded to a stretched film, and the stretched film may be sandwiched by a pair of protective films. In addition to the second resin film, more than one layer of other resins can be laminated or attached to the laminated film 4.

At the point 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 can be, for example, 3 to 100 μm, 4 to 80 μm, or 5 to 40μm. In the conventional conveying step, the smaller the thickness T8a of the central portion 8a of the transversely stretched film 8 is, the more likely it is that wrinkles are generated in the transversely stretched film 8. In other words, the thinner the central portion 8a of the transversely stretched film 8 is, the less likely it is to apply tension uniformly in the width direction of the transversely stretched film 8 due to the influence of wrinkles, so that the tension of the transversely stretched film 8 is partially increased, and The transversely stretched film 8 is easily broken. Therefore, in the conventional conveyance step, it is difficult to suppress wrinkles of the thin laterally stretched film 8 by tension. However, according to the first embodiment, even if the thickness T8a of the central portion 8a of the transversely stretched film 8 is 40 μm or less, the wrinkles of the transversely stretched film 8 during transportation can be suppressed, and the breakage of the transversely stretched film 8 can be suppressed. . The thickness of the protective film 6 may be about 10 to 100 μm, for example.

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

The conveyance speed of the protective film 6 and the laterally stretched film 8 can be, for example, 2 to 100 m/min.

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

The protrusion amount of the first roller 1 (crown roller) may be, for example, 0.05 to 5 mm. The so-called protrusion amount means the difference between the maximum value and the minimum value of the diameter in the contact area 1a of the first roller 1. In other words, the protrusion amount is the difference between the diameter of the center portion of the contact area 1a of the first roller 1 and the diameter of the end portion of the contact area 1a of the first roller 1. The convexity of the first roller 1 is a positive value obtained by subtracting the deflection of the second roller 2 from the deflection of the first roller 1. The larger the value, the easier the protection of the first roller 1 is The central portion 8a of the film 6 and the laterally stretched film 8 imparts linear pressure, which makes it easy to suppress wrinkles. If the aforementioned positive value is too large, since the ends in the width direction of the film will not be clamped, there is a concern that the effect of suppressing wrinkles will be small. Therefore, the amount of protrusion is preferably a positive value obtained by subtracting the amount of deflection of the second roll 2 from the amount of deflection of the first roll 1, and a range in which the ends in the width direction of the film can be clamped.

The laminated film obtained in the above-mentioned first embodiment can 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 system may be, for example, a laminated polarizing plate.

(Second Embodiment)

Next, the second embodiment of the present invention will be described. In the second embodiment, as in the first embodiment, wrinkles of the stretched film during transportation can be suppressed. The following describes matters unique to the second embodiment (the differences between the first embodiment and the second embodiment). Among the items not explained below, the second embodiment is the same as the first embodiment.

In the first embodiment, the first resin film 6 contacting the first roll 1 (crown) is a protective film, and the second resin film 8 contacting the second roll 2 is a stretched film. In contrast, in the second embodiment, the first resin film 6 contacting the first roll 1 (crown) is a stretched film, and the second resin film 8 contacting the second roll 2 is a protective film. In this way, the second embodiment is the same as the first embodiment except that the vertical relationship between the stretched film and the protective film is opposite.

The manufacturing method of the laminated film of the second embodiment also includes a conveying step using the conveying device 100. In the conveying step, the first resin film 6 (stretched film) and the second resin film 8 (protective film) enter between the first roller 1 and the second roller 2 from the first roller 1 side. That is, the first resin film 6 and the second resin film 8 enter between the rolls from the side of the crown roll. As a result, the first roller 1 easily applies linear pressure to the first resin film 6 and the second resin film 8. Furthermore, the contact area 1a of the first roller 1 is convex compared to a flat roller, so it can easily contact the surface of the first resin film 6 (stretched film). As shown in Figures 6 and 7, due to the above-mentioned entry direction of each resin film and the shape of the first roll 1 (crown roll), the first roll 1 can be opposed to the center of the first resin film 6 (stretched film). The portion 6a imparts linear pressure. With this linear pressure, tension can be applied to the central portion 6a of the first resin film 6 (stretched film), and wrinkles of the first resin film 6 (stretched film) can be suppressed. In addition, even if wrinkles are generated in the first resin film 6 (stretched film) located on the upstream side of the conveying device 100, the wrinkles of the first resin film 6 (stretched film) are caused by the shape of the first roll 1 (crown roll). It will also be suppressed and eliminated. By the above-mentioned mechanism, wrinkles of the first resin film 6 (stretched film) during transportation are suppressed. In particular, it is easy to suppress wrinkles of the first resin film 6 (stretched film).

At the point before the first resin film 6 (stretched film) enters between the first roll 1 and the second roll 2, as shown in Fig. 7, it is connected to the conveying direction D6 of the first resin film 6 (stretched film) The two end portions 6b of the first resin film 6 (stretched film) in the vertical direction are thicker than the central portion 6a of the first resin film 6 (stretched film) located between the two end portions 6b. That is, the both ends 6b of the first resin film 6 (stretched film) in the width direction (short-side direction or Y-axis direction) can be compared with the first resin film 6 (stretched film) located between the two ends 6b. The central part 6a of the stretched film) is thicker. In the transverse stretching step, even if the thickness T6b of the both ends 6b of the first resin film 6 (stretched film) is greater than the thickness T6a of the central part 6a, wrinkles toward the central part 6a or from the central part 6a are likely to occur. When the both ends 6b are wrinkled, in the conveying step, the contact area 1a of the first roller 1 is to fold the first resin film 6 (stretched film) toward the central part 6a or from the central part 6a to both ends The wrinkles of the part 6b are pressed open and eliminated.

As shown in Fig. 6, on the surface of the first roller 1, the width W1a of the contact area 1a in contact with the first resin film 6 (stretched film) may be narrower than the width W6 of the first resin film 6 (stretched film). When the width W1a of the contact area 1a of the first roller 1 is narrower than the width W6 of the first resin film 6 (stretched film), the contact area 1a of the first roller 1 hardly touches the first resin film 6 (stretched film) At both end portions 6b (thicker portions than the central portion 6a), the first roller 1 easily applies tension to only the central portion 6a of the first resin film 6 (stretched film). Since tension is only applied to the central portion 6a of the first resin film 6 (stretched film), the wrinkles of the first resin film 6 (stretched film) toward the central portion 6a or from the central portion 6a to both ends 6b The folds are easy to be compressed. The difference (W6 minus W1a) between the width W6 of the first resin film 6 (stretched film) and the width W1a of the contact area 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) can be narrower than the width W1a of the contact area 1a of the first roller 1. However, the width W8 of the second resin film 8 (protective film) may be wider than the width W1a of the contact area 1a of the first roller 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. The width W8 of the second resin film 8 (protective film) may be narrower than the width W2 of the second roll 2.

(Other embodiments)

The above is a description of the first embodiment and the second embodiment of the present invention, but the present invention is not limited to the above-mentioned embodiment.

The wrinkles of the resin film are not necessarily caused only by lateral stretching. For example, in the extrusion molding step of thermoplastic resin, when the molten resin discharged from the discharge port (pouring nozzle) of the extrusion die is cooled and solidified by a cooling roll, for example, it is molded into a film shape, due to the influence of necking, The ends of the extruded film tend to become thicker than the central part of the extruded film. That is, the both ends of the extruded film before lateral stretching tend to become thicker than the central part of the extruded film. The present invention is useful as a means for suppressing the wrinkles of the extruded film caused by this extrusion molding step. It is not limited to this example. In various situations in the transportation of the resin film or the manufacture of the laminated film, the present invention can suppress the wrinkles of the resin film caused by the difference in the thickness of the resin film. In the production of the laminated film, the resin film transport method of the present invention can be carried out multiple times.

The manufacturing apparatus of the laminated film of the first embodiment and the second embodiment may include a coating device in addition to a conveying device of the resin film. In the manufacturing method of the laminated film of the first embodiment and the second embodiment, a coating device can be used to apply an adhesive or an adhesive to the surface of the first resin film facing the second resin film before the conveying step. Or at least one of the surfaces of the second resin film facing the first resin film. In the subsequent conveying step, an adhesive or adhesive may be interposed between the first resin film and the second resin film, and the first resin film and the second resin film are sandwiched by the first roller and the second roller. That is, in the conveying step, the first resin film and the second resin film can be bonded via an adhesive or an adhesive. That is, the conveying device of the resin film may also have the function of laminating the resin films together.

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-adhesive properties. For example, there is a protective film made of polyethylene resin or polypropylene 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, in the conveying step, the first resin film and the second resin film may be bonded without using an adhesive or an adhesive.

For example, in the first embodiment and the second embodiment, the second roller 2 may be a crown roller. In the first embodiment and the second embodiment, the width of the contact area of the first roller may be narrower than both the width of the first resin film and the width of the second resin film. In the first and second embodiments, the two ends of the second resin film can be thicker than the central part of the second resin film located between the two ends, and the two ends of the first resin film can be thicker It is thicker than the central part of the first resin film located between the two ends.

The first resin film is not limited to a protective film or a stretched film. The second resin film is also not limited to a protective film or a stretched film. The first resin film or the second resin film may be selected from the group consisting of reflective polarizing film, anti-glare film, anti-surface reflection film, reflection film, semi-transmissive reflection film, retardation film, and viewing angle compensation film, for example. Kind of. For example, the laminated film may be composed of a polarizer, a polarizer protective film, a polarizing reflection type polarizing film, an anti-glare film, an anti-surface reflection film, a reflection film, a semi-transmissive reflection film, a retardation film, and a viewing angle compensation film. At least one type of laminated optical film in the group.

[Example]

The following examples and comparative examples are used to illustrate the content of the present invention in more detail, but the present invention is not limited to the following examples.

(Example 1)

In Example 1, the following longitudinal stretching step, lateral stretching step, and conveying step were sequentially implemented.

In the longitudinal stretching step, while heating the long strip-shaped resin film at 120°C, the resin film is stretched in the longitudinal direction (conveying direction). The resin film uses a film formed of PMMA resin (methyl methacrylate/methyl acrylate copolymer (weight ratio 94/6), glass transition temperature 108°C). _{The width W 0} of the resin film before longitudinal stretching is 1000 mm. _{The thickness T 0} of the resin film before longitudinal stretching is the value shown in Table 1 below. The longitudinal stretch magnification was adjusted to the value shown in Table 1 below. _{The thickness T 1} of the central part in the width direction (short-side direction) of the resin film (longitudinal stretched film) after longitudinal stretching is the value shown in the first table below.

In the transverse stretching step following the longitudinal stretching step, a tentering method is used. In the tentering method, a horizontal stretching device equipped with two rows of clamps arranged along both ends of the longitudinal stretching film is used. The two clamp rows are respectively composed of a plurality of clamps. In the horizontal stretching step, the two ends of the longitudinally stretched film are held by a plurality of clamps arranged along the two ends of the longitudinally stretched film. The longitudinally stretched film held by each clamp is heated at 120°C while expanding the gap between a pair of clamps in the width direction of the longitudinally stretched film, thereby stretching the width of the film in the longitudinal direction. Stretch in the direction (transverse). The stretched film is heated at the same temperature and the gap between the clamps is reduced by 5mm. Through the above steps, a longitudinally stretched film (second resin film) is obtained. The transverse stretch magnification was adjusted to the value shown in Table 1 below. As shown in FIG. 4, the both ends 8b of the width direction (short-side direction) of the obtained transversely stretched film 8 are thicker than the center part 8a of the transversely stretched film 8. As shown in FIG. That is, the both end portions 8b of the transversely stretched film 8, the remaining portion has a longitudinally stretched film with a thickness T ₁ of substantially the same thickness. The thickness T8a of the center part 8a of the transversely stretched film 8 is the value shown in the following 1st table, and is substantially uniform.

The horizontally stretched film is conveyed to the conveying device by a plurality of guide rollers. The conveying device used in Example 1, as shown in Figs. 1 and 5, includes a first roller 1 and a second roller 2 arranged in parallel, and a motor that drives the rotation of these rollers. The first roller 1 and the second roller 2 are rollers, and the first roller 1 is a crowned roller whose surface is made of rubber. The maximum diameter of the contact area 1a of the first roller 1 (crown roller) is 120 mm. The protrusion amount of the first roller 1 is 400 μm. The width W1a of the contact area 1a of the first roller 1 is 1500 mm. The second roller 2 is a flat roller made of rigid metal. The diameter of the second roller 2 is 210 mm. The width W2 of the second roller 2 is 2100 mm. In the conveying step, as shown in Figure 1, the first resin film 6 and the second resin film 8 are introduced from the side of the first roll 1 to between the first roll 1 and the second roll 2, and these are overlapped. Transport in the state. The protective film 6 (first resin film) is a long strip-shaped film formed of a polyethylene resin ("Toretec" manufactured by Toray Advanced Film Co., Ltd.). The thickness of the protective film 6 is 30 μm. The width W6 of the protective film 6 is 1450 mm. The width W6 of the protective film 6 is narrower than the width W1a of the contact area 1a of the first roller 1. The width W8a of the central portion 8a of the transversely stretched film 8 is wider than the width W6 of the protective film 6. The width W1a of the contact area 1a of the first roller 1 is narrower than the width W8a of the central portion 8a of the transversely stretched film 8. The width W2 of the second roll 2 is wider than the width W8 of the transversely stretched film 8.

Observe the protective film 6 and the laterally stretched film 8 drawn out from between the first roll 1 and the second roll 2 in an overlapping state. After the transport step of Example 1, the film 8 was stretched in the transverse direction without wrinkles.

(Example 2)

In the longitudinal stretching step of Example 2, the thickness T ₀ of the resin film before the longitudinal stretching is the value shown in the first table below. In the longitudinal stretching step of Example 2, the longitudinal stretching magnification was adjusted to the value shown in Table 1 below. _{In Example 2, the thickness T 1} of the central portion in the width direction of the longitudinally stretched film is the value shown in the first table below.

In the lateral stretching step of Example 2, the lateral stretching magnification was adjusted to the value shown in Table 1 below. In addition, in the lateral stretching step of Example 2, the gap between the clamps was reduced by 10 mm. In 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 the first table below. In Example 2, the width W8a of the central portion 8a of the transversely stretched film 8 is the value shown in the first table below.

In Example 2, the width W6 of the protective film 6 is 1450 mm, and the width W6 of the protective film 6 is narrower than the width W1a of the contact area 1a of the first roller 1.

Except for the above matters, the longitudinal stretching step, the lateral stretching step, and the conveying step of Example 2 were performed in the same manner as in Example 1. After the transport step of Example 2, the film was stretched in the transverse direction without wrinkles.

(Example 3)

In the longitudinal stretching step of Example 3, the longitudinal stretching magnification was adjusted to the value shown in Table 1 below. _{In Example 3, the thickness T 1} of the central portion in the width direction of the longitudinally stretched film is the value shown in the first table below.

In the lateral stretching step of Example 3, the lateral stretching magnification was adjusted to the value shown in Table 1 below. In addition, in the lateral stretching step of Example 3, the gap between the clamps was reduced by 10 mm. In 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 the first table below. In Example 3, the width W8a of the central portion 8a of the transversely stretched film is the value shown in the first table below.

Except for the above matters, the longitudinal stretching step, the lateral stretching step, and the conveying step of Example 3 were performed in the same manner as in Example 2. After the transport step of Example 3, there were no wrinkles on the transversely stretched film.

(Comparative example 1)

In the longitudinal stretching step of Comparative Example 1, the longitudinal stretching magnification was adjusted to the value shown in Table 1 below. _{In Comparative Example 1, the thickness T 1} of the central portion in the width direction of the longitudinally stretched film is the value shown in the first table below.

In the lateral stretching step of Comparative Example 1, the lateral stretching magnification was adjusted to the value shown in Table 1 below. In addition, in the lateral stretching step of Comparative Example 1, the gap between the clamps was reduced by 16 mm. In 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 the first table below. In Comparative Example 1, the width W6a of the central portion 6a of the stretched film is the value shown in the first table below.

As shown in Fig. 8, in the conveying step of Comparative Example 1, a flat roller 10 made of rubber was used instead of the crown roller as the first roller. The diameter of the flat roll 10 of Comparative Example 1 is 160 mm. In the transport step of Comparative Example 1, the entry angle of the first resin film 6 (stretched film) with respect to the flat roll 10 and the second roll 2 was zero. Moreover, in the conveyance process of the comparative example 1, the 2nd resin film 8 (protection film) was made to enter between the flat roll 10 and the 2nd roll 2 from the 2nd roll 2 side. As shown in Fig. 8, the vertical relationship between the stretched film and the protective film in Comparative Example 1 is opposite to that in Example 1.

In Comparative Example 1, the width W8 of the second resin film 8 (protective film) was 1900 mm. In Comparative Example 1, the width W6 of the first resin film 6 (stretched film) is narrower than the width W8 of the second resin film 8 (protective film). In Comparative Example 1, the width W6 of the first resin film 6 (stretched film) is narrower than the width of the first roll (flat roll 10) and the width W2 of the second roll 2. In Comparative Example 1, the width W8 of the second resin film 8 (protective film) is 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 matters, the longitudinal stretching step, the lateral stretching step, and the conveying step of Comparative Example 1 were performed in the same manner as in Example 1. After the conveyance 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 magnification was adjusted to the value shown in Table 1 below. _{In Comparative Example 2, the thickness T 1} of the central portion in the width direction of the longitudinally stretched film is the value shown in the first table below.

In the lateral stretching step of Comparative Example 2, the relaxation of reducing the interval between the clamps was not performed. The transverse stretch magnification was adjusted to the value shown in Table 1 below. In Comparative Example 2, the thickness T8a of the central portion 8a in the width direction of the obtained transversely stretched film was the value shown in the first table below. In Comparative Example 2, the width W8a of the central portion 8a of the stretched film is the value shown in the first table below.

The width W1 of the entire first roller 1 (crown roller) used in the transport step of Comparative Example 2 was 2100 mm. The width W1a of the contact area 1a of the first roller 1A (crown roller) of Comparative Example 2 is 1591 mm. The protrusion amount of the first roller 1 of Comparative Example 2 was 1200 μm. As shown in FIG. 9, in the conveying step of Comparative Example 2, the laterally stretched film 8 was moved from the second roll 2 side to between the first roll 1 and the second roll 2.

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

Except for the above matters, the longitudinal stretching step, the lateral stretching step, and the conveying step of Comparative Example 2 were performed in the same manner as in Example 1. After the conveyance step of Comparative Example 2, there were no wrinkles in the center part of the transversely stretched film 8, but wrinkles were generated at both ends of the transversely stretched film 8.

(Comparative example 3)

In the lateral stretching step of Comparative Example 3, the gap between the clamps was loosened by 5 mm. The thickness T8a of the center part 8a of the width direction of the obtained transversely stretched film 8 is the value shown in the following 1st table. In Comparative Example 3, the width W8a of the central portion 8a of the transversely stretched film 8 is the value shown in the first table below.

In the conveyance step of Comparative Example 3, the transversely stretched film 8 was brought into between the first roller 1 and the second roller 2 from the second roller 2 side.

Except for the above matters, the longitudinal stretching step, the lateral stretching step, and the conveying step of Comparative Example 3 were performed in the same manner as in Example 1. After the conveyance step of Comparative Example 3, the transversely stretched film 8 was slightly wrinkled.

[Industrial Utilization]

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

1‧‧‧The first roll

1a‧‧‧The contact area of the first roller

1b‧‧‧ Both ends

2‧‧‧The second roll

4‧‧‧Laminated film

6‧‧‧The first resin film

8‧‧‧Second resin film

100‧‧‧Resin film conveying device

A1, A2‧‧‧axis of rotation

D6, D8‧‧‧Conveying direction

L1‧‧‧First Baseline

L2‧‧‧Second Baseline

La‧‧‧line segment

θ1, θ2‧‧‧Entry angle

Claims (17)

A method for conveying a resin film, comprising: a first resin film and a second resin film are sandwiched by a first roller and a second roller while being overlapped with each other, and conveyed; wherein the first roller is a crown roller, The first resin film and the second resin film enter from the first roller side to between the first roller and the second roller, the entry angle of the second resin film is 10 to 170°, and the entry angle is The included angle of the second resin film with respect to a second reference line is perpendicular to a line segment connecting the rotation axis of the first roller and the rotation axis of the second roller. The method for conveying a resin film as described in claim 1, wherein the second resin film is in the same direction as the conveying direction of the second resin film before the second resin film enters between the first roller and the second roller. At least one of the two ends of the second resin film in the vertical direction is thicker than the center of the second resin film located between the two ends. The method for conveying a resin film as described in claim 1 or 2, wherein, on the surface of the first roller, the width of the contact area in contact with the first resin film is greater than that of the second roller The aforementioned second resin film in contact has a narrow width. The method for conveying a resin film as described in item 1 or item 2 of the scope of the patent application, wherein, at the time before the first resin film enters between the first roller and the second roller, the first resin film is Transport of the film At least one of the two ends of the first resin film in the direction perpendicular to the direction is thicker than the central portion of the first resin film located between the two ends. The method for conveying a resin film as described in claim 1 or 2, wherein in the surface of the first roll, the width of the contact area in contact with the first resin film is greater than that of the first resin film. The width is narrow. The method for transporting a resin film as described in claim 1 or 2, wherein the entire surface of the first resin film is in contact with the surface of the first roller. A method of manufacturing a laminated film is a method of manufacturing a laminated film in which a first resin film and a second resin film are laminated, and includes: the first resin film and the second resin film are superimposed on each other with the first resin film The step of nipping and conveying the roller and the second roller; wherein the first roller is a crowned roller, and in the conveying step, the first resin film and the second resin film are moved from the first roller side to the first The entry angle of the second resin film is 10 to 170°, and the entry angle is the angle between the second resin film and the second reference line. The second reference line is connected to the The line segment between the rotation axis of the first roller and the rotation axis of the second roller is perpendicular. The manufacturing method of the laminated film as described in claim 7, wherein the second resin film is transferred between the first roll and the second roll At the time before the time enters, at least one of the two ends of the second resin film in the direction perpendicular to the conveying direction of the second resin film is located more than the center of the second resin film between the two ends Department is thicker. The manufacturing method of the laminated film as described in claim 7 or 8, wherein the width of the contact area in contact with the first resin film on the surface of the first roll is greater than that of the second roll The aforementioned second resin film in contact has a narrow width. The method for conveying the laminated film described in item 7 or item 8 of the scope of patent application, wherein the first resin film is at a point before the first resin film enters between the first roller and the second roller. At least one of the two ends of the first resin film in the direction perpendicular to the transport direction of the film is thicker than the central portion of the first resin film located between the two ends. The method for conveying a laminated film as described in claim 7 or 8, wherein, on the surface of the first roll, the width of the contact area in contact with the first resin film is greater than that of the first resin film. The width is narrow. The method for transporting the laminated film described in the scope of the patent application item 7 or 8, wherein the entire surface of the first resin film is in contact with the surface of the first roller. The method for transporting a laminated film as described in item 7 or item 8 of the scope of the patent application, wherein, in the transporting step, an adhesive or an adhesive is interposed in the first resin film and Between the second resin film, the first resin film and the second resin film are sandwiched by the first roller and the second roller, thereby bonding the first resin film and the second resin film. The method for transporting a laminated film according to claim 7 or 8, wherein at least one of the first resin film and the second resin film is a self-adhesive film. A conveying device for a resin film, comprising: a first roller and a second roller that sandwich and convey a first resin film and a second resin film while overlapping each other; and the conveying device is configured as: the first roller A crown roll; the first resin film and the second resin film enter from the first roll side to between the first roll and the second roll, and the entry angle of the second resin film is 10 to 170°, The entry angle is an included angle of the second resin film with respect to a second reference line, and the second reference line is perpendicular to a line segment connecting the rotation axis of the first roller and the rotation axis of the second roller. A manufacturing device for a laminated film is a device for manufacturing a laminated film in which a first resin film and a second resin film are laminated, and is provided with a conveying device as described in the 15th patent application. The manufacturing device of the laminated film described in the scope of patent application, further comprising: applying an adhesive or adhesive to the surface of the first resin film facing the second resin film, or the second resin film The coating device faces at least any one of the surfaces of the aforementioned first resin film.

Images