TWI732956B - 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 comprises a step of conveying a first resin film (6) and a second resin film (8) that are gripped between a first roller (1) and a second roller (2) in a state of being overlapped with each other, wherein the first roller (1) contacts the first resin film (6), the second roller (2) contacts the second resin film (8), the width (W1a) of the contact region (1a) in contact with the first resin film (6) in the surface of the first roller (1) is narrower than at least one of the width (W6) of the first resin film (6) and the width (W8) of the second resin film (8), and the first resin film (6) and the second resin film (8) are caused 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 respectively gripped 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 wrinkles of the resin film mentioned above 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, which includes the step of sandwiching and transporting the first resin film and the second resin film in a state where they overlap each other with a first roller and a second roller; wherein, The first roller is in contact with the first resin film, and the second roller is in contact with the second resin film. The width of the contact area on the surface of the first roller that is in contact with the first resin film is greater than the width of the first resin film and the second At least one of the widths of the resin film is narrow, so that the first resin film and the second resin film enter between the first roller and the second roller from the first roller side.

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 also be referred to as 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 referred to as 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 also be referred to as the longitudinal direction 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" may also be referred to as 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" may also be referred to as the width of the first resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped 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" may also be referred to as 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" may also be referred to as the width of the second resin film in the direction perpendicular to the longitudinal direction of the long strip-shaped second resin film. The conveyance direction of the second resin film may also be referred to as the longitudinal direction of the second resin film.

In one aspect of the method for conveying a facing resin film of the present invention, the first resin film 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 part 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" can also be referred to as the two 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" can also be referred to as the two ends 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 method for conveying a facing resin film of the present invention, the second resin film 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 part 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 both ends of the second resin film" can also be referred to as the two ends of the second resin film in a direction parallel to the rotation axis of the second roller. "The both ends of the second resin film" can also be referred to as the two ends 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 for conveying a facing resin film of the present invention, the width of the contact area of the first roller can be narrower than the width of the second resin film, and 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, which 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 stacked on each other A conveying step in which the first roller and the second roller are nipped and conveyed in the state; wherein, in the conveying step, the first roller contacts the first resin film, the second roller contacts the second resin film, and the The width of the contact area in contact with the first resin film on the surface is narrower than at least one of the width of the first resin film and the width of the second resin film. The film enters 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 first resin film in the direction perpendicular to the conveying direction of the first resin film before the first resin film enters between the first roll and the second roll At least one of the two ends of the film is thicker than the central part of the first resin film located between the two ends.

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

In the manufacturing method of the laminated film facing one aspect of the present invention, the width of the contact area of the first roller can be narrower than the width of the second resin film, and the entire surface of the first resin film can be brought into contact with the surface of the first roller.

In the conveying step of the manufacturing method of the laminated film facing one aspect of the present invention, an adhesive or a pressure-sensitive adhesive can be interposed between the first resin film and the second resin film, and the first roller and the second resin film The two rollers sandwich the first resin film and the second resin film, thereby bonding the first resin film and the second resin film.

In the manufacturing method of the laminated film which is one aspect of this invention, at least one of the 1st resin film and the 2nd resin film is 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 in a state where they overlap each other; and are configured as: One roller is in contact with the first resin film, and the second roller is in contact with the second resin film. The width of the contact area on the surface of the first roller that is in contact with the first resin film is greater than the width of the first resin film and the second resin At least one of the widths of the film is narrow, so that the first resin film and the second resin film enter between the first roller and the second roller from the first roller side.

One aspect of the present invention is a manufacturing apparatus for a laminated film, which is an apparatus for manufacturing a laminated film in which a first resin film and a second resin film are laminated, and is provided with the above-mentioned conveying device.

One aspect of the present invention is a laminated film manufacturing apparatus, 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 facing the first resin film Coating device for at least any one of the surfaces.

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 roll

1A‧‧‧First roller (Crown roller)

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

1b‧‧‧ Both ends

2‧‧‧The second roll

4‧‧‧Laminated film

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

6a‧‧‧The central part of the first resin film

6b‧‧‧ Both ends of the first resin film

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

8a‧‧‧The central part of the second resin film

8b‧‧‧ Both ends of the second resin film

10‧‧‧Flat Roll

100‧‧‧Transfer position of resin film

A1‧‧‧The axis of rotation of the first roller

A2‧‧‧The axis of rotation of the second roller

T6a‧‧‧The thickness of the central part of the first resin film

T6b‧‧‧The thickness of both ends of the first resin film

T8a‧‧‧The thickness of the central part of the second resin film

T8b‧‧‧The thickness of both ends of the second resin film

W1a‧‧‧The width of the contact area of the first roller

W2‧‧‧The width of the second roller

W6‧‧‧The width of the first resin film

W6a‧‧‧The width of the central part of the first resin film

W8‧‧‧The width of the second resin film

W8a‧‧‧The width of the central part of the second resin film

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 cross-sectional view 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 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. 6 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. 7 is a schematic cross-sectional view of a resin film transport device, a first resin film, and a second resin film according to the third embodiment of the present invention.

Fig. 8 is a modified example of the cross section shown in Fig. 7, 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. 9 is a schematic diagram of the conveying device and the conveying method of the resin film of Comparative Example 1.

Fig. 10 is a schematic diagram of the conveying device and the 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. Hereinafter, 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.

Stretching in the longitudinal direction is followed by stretching in the transverse direction. Hereinafter, the tenter method will be described as an example of the lateral 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, you can perform an operation to narrow the gap slightly (so-called loosening). 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 transversely stretched film is conveyed to the slitting device by the conventional conveying method using guide rolls or nip rolls, the stretched film being conveyed is prone to wrinkles. 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 transversely stretched film during transportation are not necessarily caused only by the thickness difference. 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. 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 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 may be, for example, a flat roller having a substantially uniform diameter. That is, as shown in FIG. 3, the surface of the first roller 1 may be substantially straight in a cross section including the rotation axis A1 of the first roller 1. The second roller 2 may also be a flat roller. That is, as shown in FIG. 3, the surface of the second roller 2 may be substantially straight in a cross section including the rotation axis A2 of the second roller 2.

The width W1a of the contact area 1a in contact with the protective film 6 (first resin film) on the surface of the first roller 1 is greater than the central part of the transversely stretched film 8 (second resin film) in contact with the second roller 2 The width W8a of 8a is narrow. When the width W1a of the contact area 1a contacted by the first roller 1 is narrower than the width W8a of the central portion 8a of the transversely stretched film 8 (second resin film), the contact area 1a of the first roller 1 is difficult to abut against the transversely stretched film 8 (second resin film). The both ends 8b (thicker parts of the central part 8a) of the stretched film 8 (second resin film), the first roller 1 easily applies tension only to the central part 8a of the transverse stretched film 8 (second resin film) . By applying tension only to the central portion 8a of the laterally stretched film 8 (second resin film), wrinkles are less likely to occur in the central portion 8a having a uniform thickness. The difference (W8-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.

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 first roll 1 whose width is narrower than that of the laterally stretched film 8. As a result, the contact area 1 a of the first roller 1 is made easy to apply uniform linear pressure to the central portion 8 a of the laterally stretched film 8 via the protective film 6.

As described above, in the first embodiment, the first roller 1 can apply a sufficiently uniform linear pressure to the central portion 8a of the transversely stretched film 8 via the protective film 6. With this uniform linear pressure, uniform tension can be imparted to the central portion 8a of the transversely stretched film 8. As a result, wrinkles of the laterally stretched film 8 during transportation can be suppressed. In particular, it is easy to suppress wrinkles from both ends 8b of the transversely stretched film 8 toward the central portion 8a, or wrinkles from the center 8a to both ends 8b, and it is easy to suppress the central portion 8a of the transversely stretched film 8. Wrinkles caused by the difference in thickness with both ends 8b. 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 uniform linear pressure to the central portion 8a of the transversely 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 entrance 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 transverse stretched film 8 can be suppressed Wrinkled.

As shown in FIG. 3, the entire 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). 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) and linear pressure is applied to the central portion 8a of the transversely stretched film 8 (second resin film). As a result, it is possible to suppress wrinkles toward the center portion 8a of the transversely stretched film 8 or wrinkles from the center portion 8a toward both end portions 8b.

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 transversely 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 first 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), and the surface of the first roller 1 may also be subjected to surface treatment such as chrome plating or nickel plating. 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 elastomer. 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 transport 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 laterally stretched film 8 is, the less likely it is to apply tension uniformly in the width direction of the laterally stretched film 8 due to the influence of wrinkles and the like, so that the tension of the laterally 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 may be 60 to 400 mm, for example. The diameter of the second roller 2 may be 60 to 400 mm, for example.

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 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 roller 1 is a stretched film, and the second resin film 8 contacting the second roller 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.

As shown in Figures 5 and 6, the width W1a of the contact area 1a in contact with the first resin film 6 (stretched film) on the surface of the first roll 1 is greater than that of the first resin film 6 (stretched film). ) Has a narrow width W6. 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 abuts against 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 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) or from the central portion 6a can be suppressed Wrinkles at both ends 6b. The difference (W6-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 resin film 6 (stretched film) may be about 10 to 300 mm, for example.

In the conveyance step, the first resin film 6 (stretched film) and the second resin film 8 (protective film) are brought into 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 allowed to enter between the rolls from the side of the first roll 1 whose width is narrower than that of the first resin film 6. As a result, it is easy for the first roller 1 to apply linear pressure to the central portion 6 a of the first resin film 6 and the second resin film 8.

As described above, in the second embodiment, the first roller 1 can sufficiently apply uniform linear pressure to the central portion 6a of the first resin film 6 (stretched film). With this linear pressure, uniform tension can be imparted to the central portion 6a of the first resin film 6 (stretched film), and wrinkles can be suppressed. In particular, it is easy to suppress wrinkles at both ends 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 Figs. 5 and 6, the first resin film 6 (stretched film) The two ends 6b of the first resin film 6 (stretched film) in the direction perpendicular to the conveying direction D6 are more than the central portion 6a of the first resin film 6 (stretched film) located between the two ends 6b thick. 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 lateral 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 portion 6a, when wrinkles are likely to occur toward the central portion 6a, in the conveying step Since the contact area 1a of the first roller 1 can also apply uniform tension to the central portion 6a of the first resin film 6 (stretched film), the generation of wrinkles can be suppressed.

As shown in FIG. 5, 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. 5, 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. 5, 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.

(Third Embodiment)

Next, the third embodiment of the present invention will be described. Also in the third embodiment, as in the first and second embodiments, wrinkles of the first resin film 6 or the second resin film 8 can be suppressed. Hereinafter, matters unique to the third embodiment will be explained. Among the items not explained below, the third embodiment is the same as the first embodiment. In addition, in matters not described below, the third embodiment and the second embodiment are common.

As shown in Fig. 7, the first roller 1A of the third embodiment is a crowned roller. That is, in the cross section including the rotation axis A1 of the first roller 1A, the surface of the contact area 1a in the center of the first roller 1A has a gentle curve. In addition, the diameter (thickness) of the first roller 1A decreases from the center of the first roller 1A toward the both ends 1b of the first roller 1A. On the other hand, the second roller 2 of the third embodiment may be, for example, a flat roller. However, the actual second roller 2 can be bent along the contact area 1a of the first roller 1A due to its own weight, for example.

In the conveying step of the third embodiment, the first resin film 6 and the second resin film 8 are also made to enter between the first roller 1A and the second roller 2 from the side of the first roller 1A. That is, the first resin film 6 and the second resin film 8 are allowed to enter between the rolls from the side of the crown roll. Since the contact area 1a (the thicker part of the crown roller) of the first roller 1A is convex compared to the flat roller, it is easy to contact the surface of the first resin film 6. Therefore, the first roll 1A (crown roll) is easier to uniformly apply tension to the central portion 6a of the first resin film 6 or the central portion 8a of the second resin film 8 than a flat roll, so that the first resin film 6 or The second resin film 8 is not prone to wrinkles. That is, according to the third embodiment using a crown roll, it is easier to suppress the wrinkles of the first resin film 6 or the second resin film 8 compared to the first embodiment and the second embodiment using a flat roll. If one or both of the first resin film 6 and the second resin film 8 enters between the first roller 1A and the second roller 2 from the side of the second roller 2, the contact area 1a (crown) of the first roller 1A The thicker part of the roller) makes it difficult to uniformly press and apply threads to each resin film, and it is difficult to suppress wrinkles.

The protrusion amount of the first roller 1A (crown roller) may be, for example, 0.05 to 5 mm. The so-called protrusion amount is the difference between the maximum value and the minimum value of the diameter in the contact area 1a of the first roller 1A. In other words, the amount of protrusion is the difference between the diameter of the center portion of the contact area 1a of the first roller 1A and the diameter of the end portion of the contact area 1a of the first roller 1A. The amount of protrusion of the first roller 1A is a positive value after subtracting the amount of curvature of the second roller 2 from the amount of curvature of the first roller 1, and the greater the value, the easier it is for the first roller 1A to apply linear pressure to The central portion 8a of the first resin film 6 and the second resin film 8 can easily suppress wrinkles. When the aforementioned positive value is too large, the ends in the width direction of the film cannot be clamped, and therefore the wrinkle suppression effect may be reduced. Therefore, it is preferable that the amount of protrusion is a positive value obtained by subtracting the amount of curvature of the second roller 2 from the amount of curvature of the first roller 1 and a range of the extent that the ends of the film width direction can be clamped.

As shown in Fig. 7, a part of the surface of the first resin film 6 can be made to adhere to the surface of the first roller 1A (the contact area 1a of the first roller 1), or as shown in Fig. 8, the The entire surface of a resin film 6 is in close contact with the surface of the first roller 1A (the contact area 1a of the first roller 1). The larger the surface area of the first resin film 6 adhering to the surface of the first roller 1A (the contact area 1a of the first roller 1), the easier it is for the contact area 1a of the first roller 1A to pass linear pressure through the first resin film 6 It is applied to the central portion 8a of the second resin film 8. As a result, it is possible to suppress wrinkles toward the center portion 8a of the second resin film 8 or wrinkles toward the both end portions 8b from the center portion 8a. In addition, even if wrinkles occur in the second resin film 8 located on the upstream side of the conveying device 100, the wrinkles of the second resin film 8 are easily flattened due to the shape of the first roll 1A (crown roll).

(Other embodiments)

The first, second, and third embodiments of the present invention have been described above, but the present invention is not limited to the above-mentioned embodiments.

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 1st, 2nd, and 3rd embodiment may be equipped with the coating apparatus in addition to the conveying apparatus of a resin film. In the manufacturing methods of the laminated film of the first, second, and third embodiments, before the conveying step, a coating device can be used to apply the adhesive or adhesive to the first resin film facing the second resin film. At least one of the surface of the resin film or the surface of the second resin film facing the first resin film. In the subsequent conveying step, an adhesive or an 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 third embodiment described above, the second roller 2 may be a crowned roller. In the first, second, and third embodiments, the width of the contact area of the first roller can be narrower than both the width of the first resin film and the width of the second resin film. In the first, second, and third embodiments, the both 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 first resin film The two ends may be 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, for example, 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 One of the group. The laminated film may be, for example, a film selected from 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 consisting of.

[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 W0 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 center part in the width direction (short-side direction) of the resin film (longitudinal stretched film) after the longitudinal stretching is the value shown in the following Table 1.

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 while reducing the gap between the clamps 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 8, includes a first roller 1A and a second roller 2 arranged in parallel, and a motor that drives the rotation of these rollers. The first roller 1A and the second roller 2 are rollers, and the first roller 1A is a crowned roller whose surface is made of rubber. The maximum diameter of the contact area 1a of the first roller 1A (crown roller) is 120 mm. The protrusion amount of the first roller 1A 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 1A to between the first roll 1A and the second roll 2, and these are overlapped. Transport in the state. As the protective film 6 (first resin film), a long strip-shaped film made of polyethylene resin ("Toretec" manufactured by Toray Advanced Film Co., Ltd.) was used. 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 1A. 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. As shown in FIG. The width W1a of the contact area 1a of the first roller 1A is narrower than the width W8a of the central portion 8a of the transversely stretched film 8. The width W2 of the second roller 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 1A 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 1A.

Except for the above matters, the longitudinal stretching step, the transverse stretching step, and the conveying step of the second embodiment were carried out in the same manner as in the first embodiment. 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 Table 1 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. 9, in the transport 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 Figure 9, 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 1A (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 1A of Comparative Example 2 was 1200 μm. As shown in FIG. 10, in the conveyance step of the comparative example 2, the transversely stretched film 8 was made to enter between the 1st roll 1A and the 2nd roll 2 from the 2nd roll 2 side.

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 1A. In Comparative Example 2, the width W1a of the contact area 1a of the first roller 1A 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 1A 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 transport step of Comparative Example 3, the transversely stretched film 8 only slightly wrinkles.

[Industrial availability]

According to the resin film transport method of the present invention, when the stretched film (e.g., polarizer film) is transported in the manufacturing process of the laminate film (e.g., laminate type polarizing plate), 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‧‧‧Transfer position of resin film

A1‧‧‧The axis of rotation of the first roller

A2‧‧‧The axis of rotation of the second roller

W1a‧‧‧The width of the contact area of the first roller

W2‧‧‧The width of the second roller

W6‧‧‧The width of the first resin film

W8‧‧‧The width of the second resin film

Claims (13)

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 in contact with The first resin film and the second roller are in contact with the second resin film; the width of the contact area on the surface of the first roller that contacts the first resin film is larger than the width of the first resin film and the width of the first resin film. At least one of the widths of the second resin film is narrow, so that the first resin film and the second resin film enter between the first roller and the second roller from the first roller side. The method for conveying a resin film as described in claim 1, wherein, at a point before the first resin film enters between the first roller and the second roller, the direction of conveyance of the first resin film is At least one of the two ends of the first resin film in the vertical 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 the first or second scope of the patent application, wherein the time before the second resin film enters between the first roller and the second roller, and the second resin film At least one of the two ends of the second resin film in the direction perpendicular to the conveying direction is thicker than the central portion of the second resin film located between the two ends. According to the method for conveying the resin film described in item 1 or 2, wherein the width of the contact area of the first roller is narrower than the width of the second resin film; The entire surface of the first resin film is brought into 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 in a first A conveying step in which a roller and a second roller are nipped and conveyed; in the conveying step, the first roller is in contact with the first resin film, and the second roller is in contact with the second resin film; The width of the contact area on the surface that is in contact with the first resin film is narrower than at least one of the width of the first resin film and the width of the second resin film. The film and the second resin film enter between the first roller and the second roller from the first roller side. The manufacturing method of the laminated film described in the scope of patent application 5, wherein, at a point before the first resin film enters between the first roller and the second roller, the direction of conveyance of the first resin film is different from that of the first resin film. At least one of the two ends of the first resin film in the vertical direction is thicker than the central portion of the first resin film located between the two ends. The manufacturing method of the laminated film described in the scope of patent application 5 or 6, wherein, at the time before the second resin film enters between the first roll and the second roll, the difference between the second resin film and the second resin film At least one of the two ends of the second resin film in the direction perpendicular to the conveying direction is thicker than the central portion of the second resin film located between the two ends. The manufacturing method of the laminated film described in the scope of patent application 5 or 6, wherein the width of the contact area of the first roll is narrower than the width of the second resin film; the entire surface of the first resin film It is in contact with the surface of the aforementioned first roller. The method for manufacturing a laminated film as described in item 5 or 6 of the scope of the patent application, wherein in the conveying step, an adhesive or an adhesive is interposed between the first resin film and the second resin film to The first roller and the second roller sandwich the first resin film and the second resin film, thereby bonding the first resin film and the second resin film. The manufacturing method of the laminated film as described in the 5th or 6th patent application scope, 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: A roller is in contact with the first resin film, and the second roller is in contact with the second resin film; the width of the contact area in contact with the first resin film on the surface of the first roller is larger than that of the first resin film At least one of the width of the second resin film and the width of the second resin film is narrow, so that the first resin film and the second resin film go from the first roll side to the first roll and Enter between the aforementioned second rollers. 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 item 11 of the scope of patent application. The manufacturing apparatus of the laminated film described in the scope of the patent application is further equipped with: applying an adhesive or adhesive to the surface of the first resin film facing the second resin film, or facing the first resin A coating device for at least any one of the surfaces of the aforementioned second resin film of the film.

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