JP7644157B2 - Manufacturing method of edge film - Google Patents

Description

The present invention relates to a method for manufacturing an end film.

Stretched films, which are widely used in various industrial products, are manufactured by stretching a resin film. For example, a method for manufacturing a stretched film has been proposed in which a long resin film is stretched in a direction intersecting the long length direction while both ends in the width direction of the film are held by clips (see, for example, Patent Document 1). In such a method for manufacturing a stretched film, clip marks are left on both ends in the width direction of the stretched film. Therefore, the ends including the marks are generally cut off from the stretched film and discarded.
In recent years, from the viewpoint of reducing the environmental load, it is desired to reuse waste generated during the manufacture of various industrial products. Therefore, in the method for producing a stretched film described in Patent Document 1, it has been considered to recover the end portions cut from the stretched film as end films and to make effective use of them. However, when recovering the end films, the end films may break, making the recovery of the end films complicated.

Patent No. 7096940

The present invention has been made to solve the above-mentioned problems of the conventional art, and its main objective is to provide a method for manufacturing end films that can suppress breakage of the end films and enable smooth production of end films.

[1] A method for manufacturing an end film according to an embodiment of the present invention includes the steps of: stretching a long resin film in a direction intersecting the long length direction while holding each of both widthwise ends of the film with a clip to prepare a stretched film; cutting each of both ends, including the clip marks, from the stretched film to separate it into a first end film including the clip marks, and an intermediate film; and cutting each of both widthwise ends of the intermediate film to separate it into a second end film and a product film.
[2] The method for manufacturing an end film described in [1] above may further include a step in which a winding member winds up the second end film.

According to an embodiment of the present invention, breakage of the end film can be suppressed, and the end film can be manufactured smoothly.

FIG. 1 is a schematic diagram for explaining a method for manufacturing an edge film according to one embodiment of the present invention. FIG. 2 is a plan view of the stretched film of FIG. FIG. 3 is a plan view of the intermediate film of FIG.

The following describes embodiments of the present invention, but the present invention is not limited to these embodiments. In addition, in order to make the description clearer, the drawings may show the width, thickness, shape, etc. of each part more diagrammatically than in the embodiments, but these are merely examples and do not limit the interpretation of the present invention.

(Definition of terms and symbols)
The definitions of terms and symbols used in this specification are as follows.
(1) Refractive index (nx, ny, nz)
"nx" is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the in-plane direction perpendicular to the slow axis (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction.
(2) In-plane phase difference (Re)
"Re(λ)" is the in-plane retardation measured with light having a wavelength of λ nm at 23° C. For example, "Re(550)" is the in-plane retardation measured with light having a wavelength of 550 nm at 23° C. Re(λ) is calculated by the formula: Re(λ)=(nx−ny)×d, where d (nm) is the thickness of the layer (film).
(3) Angles When angles are referred to in this specification, unless otherwise specified, the angles include angles in both clockwise and counterclockwise directions.

A. Overview of the Method for Producing an End Film FIG. 1 is a schematic diagram for explaining a method for producing an end film according to one embodiment of the present invention; FIG. 2 is a plan view of the stretched film in FIG. 1; and FIG. 3 is a plan view of the intermediate film in FIG. 1.

The manufacturing method of the end film according to the embodiment of the present invention includes a stretching step, a first cutting step, and a second cutting step in this order (see FIG. 1). In the stretching step, the resin film 1 is stretched in a direction intersecting the longitudinal direction while each of both ends in the width direction of the long resin film 1 is held by a clip, to prepare a stretched film 2. In the first cutting step, each of both ends including the clip holding marks 41 is cut from the stretched film 2 to separate it into a first end film 4 including the holding marks 41 and an intermediate film 3 (see FIG. 2). In the second cutting step, each of both ends in the width direction of the intermediate film 3 is cut to separate it into a second end film 5 and a product film 6 (see FIG. 3).
The present inventors have discovered that when recovering (manufacturing) the end film, the gripping marks of the clip become the starting point of cracks, causing the end film to break. As a result of intensively studying the means for recovering the end film, it has been found that the breakage of each end film can be suppressed by separating the end film including the gripping marks of the clip from the end film not including the gripping marks of the clip and recovering them by an appropriate means. Specifically, both ends including the gripping marks of the clip 41 are cut from the stretched film 2 to separate it into the first end film 4 including the gripping marks of the clip 41 and the intermediate film 3, and then both ends in the width direction of the intermediate film 3 are further cut to separate it into the second end film 5 and the product film 6. This allows each of the first end film 4 and the second end film 5 to be recovered by an appropriate means. As a result, the end film can be smoothly manufactured (recovered) while suppressing the breakage of the end film (the first end film and the second end film). In other words, the method for producing an end film according to an embodiment of the present invention is a method for recovering an end film.

The first end film 4 can be recovered by any suitable means. In one embodiment, the method for manufacturing the end film further includes a recovery step of recovering the first end film 4. The first end film 4 includes gripping marks 41 of the clip, which are relatively hard and brittle. Therefore, in the recovery step, the first end film 4 is recovered without being wound up. This can prevent the first end film from breaking.

The second end film 5 can be recovered by any suitable means. In one embodiment, the method for manufacturing the end film further includes a first winding step in which the first winding member 8 winds up the second end film 5. The second end film 5 does not substantially include the gripping marks 41 of the clip. Therefore, in the first winding step, even if the second end film 5 is wound up, breakage of the second end film 5 can be suppressed. As a result, the second end film 5 can be smoothly recovered in a roll, and the end film roll 100 in which the second end film 5 is wound in a roll can be smoothly manufactured. In the end film roll 100, the second end film 5 is layered in the radial direction of the first winding member 8.

The recovered end films (each of the first end film and the second end film) are independently distributable products that can be used industrially, and are typically used as recycled resin raw materials.
The recycled resin raw material can be used to manufacture any suitable resin product. Examples of the resin product include optical films such as retardation films; packaging materials made of thermoplastic resins such as polyethylene terephthalate (PET) and nylon; and the like. Among these resin products, optical films are preferred, and retardation films are more preferred. In other words, the recovered end film can be suitably used as a raw material for optical films (typically retardation films).

Below, we will explain each step of the end film manufacturing method in detail.

B. Stretching Step As shown in FIG. 1, in the stretching step, a long resin film 1 is stretched, typically by a stretching device 10.

B-1. Resin film to be stretched In this specification, the resin film 1 refers to a film before the stretching process. Any appropriate film may be adopted as the resin film 1. As described above, the resin film 1 has a long shape. Any appropriate value may be adopted as the dimension in each direction of the resin film 1. The width of the resin film 1 (the dimension in the direction perpendicular to the long direction) is, for example, 500 mm or more, preferably 700 mm or more, and, for example, 2500 mm or less, preferably 2000 mm or less. The thickness of the resin film 1 is, for example, 40 μm or more, preferably 60 μm or more, and, for example, 200 μm or less, preferably 180 μm or less.

Examples of resin materials constituting the resin film 1 include polycarbonate-based resins, polyvinyl acetal-based resins, cycloolefin-based resins, (meth)acrylic-based resins, cellulose ester-based resins, cellulose-based resins, polyester-based resins, polyester carbonate-based resins, olefin-based resins, and polyurethane-based resins. Note that (meth)acrylic-based resins refer to acrylic-based resins and/or methacrylic-based resins. These resin materials can be used alone or in combination.

Among the resin materials constituting the resin film 1, polycarbonate (PC)-based resins, cycloolefin (COP)-based resins, (meth)acrylic resins, and polyester-based resins (typically polyethylene terephthalate (PET)) are preferred, and PC-based resins are more preferred. When such resin materials are used, the second end film can be more stably recovered in the first winding process.

Examples of PC-based resins include PC-based resins that contain structural units derived from dihydroxy compounds. Specific examples of the dihydroxy compound include 9,9-bis(4-hydroxyphenyl)fluorene, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 9,9-bis(4-hydroxy-3-ethylphenyl)fluorene, 9,9-bis(4-hydroxy-3-n-propylphenyl)fluorene, 9,9-bis(4-hydroxy-3-isopropylphenyl)fluorene, 9,9-bis(4-hydroxy-3-n-butylphenyl)fluorene, 9,9-bis(4-hydroxy-3-sec-butylphenyl)fluorene, 9,9-bis(4-hydroxy-3-tert-butylphenyl)fluorene, 9,9-bis(4-hydroxy-3-cyclohexylphenyl)fluorene, 9,9-bis(4-hydroxy-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, and 9,9-bis( 4-(2-hydroxyethoxy)-3-methylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isopropylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-isobutylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-cyclohexyl phenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-phenylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3,5-dimethylphenyl)fluorene, 9,9-bis(4-(2-hydroxyethoxy)-3-tert-butyl-6-methylphenyl)fluorene, 9,9-bis(4-(3-hydroxy-2,2-dimethylpropoxy)phenyl)fluorene. In addition to the structural units derived from the dihydroxy compounds, the PC resin may contain structural units derived from dihydroxy compounds such as isosorbide, isomannide, isoidet, spiroglycol, dioxane glycol, diethylene glycol (DEG), triethylene glycol (TEG), polyethylene glycol (PEG), cyclohexane dimethanol (CHDM), tricyclodecane dimethanol (TCDDM), and bisphenols.

Details of the above-mentioned PC resins are described, for example, in JP 2012-67300 A and Japanese Patent No. 3325560. The descriptions in these patent documents are incorporated herein by reference.

B-2. Stretching Device In one embodiment, the resin film 1 is transported in the longitudinal direction so as to pass through the stretching device 10. Therefore, the resin film 1 can be stretched while being transported, and the stretched film 2 can be continuously prepared.

Although not shown, the stretching device 10 is equipped with clips capable of gripping the widthwise ends of the resin film 1. The stretching device 10 is typically a tenter stretching device. The stretching device 10 stretches the resin film 1 in a direction intersecting with the longitudinal direction while each of the widthwise ends of the resin film 1 is gripped (typically clamped) by a clip. The stretching direction may be a direction substantially perpendicular to the longitudinal direction of the resin film 1 (for example, 90°±1° with respect to the longitudinal direction), or may be a direction intersecting both the longitudinal direction and the width direction of the resin film 1.

Details of the stretching process are described, for example, in Japanese Patent No. 7096940, Japanese Unexamined Patent Publication No. 2004-226686, and International Publication No. 2007/111313. The descriptions in these patent documents are incorporated herein by reference.

As a result, a long stretched film 2 is prepared as shown in FIG. 2. The stretching ratio in the width direction in the stretching process (width of stretched film/width of resin film) is, for example, 1.1 or more, preferably 1.5 or more, and, for example, 6.0 or less, preferably 4.0 or less.

Clip marks 41 are formed on both ends of the stretched film 2 in the width direction. The clip marks 41 are harder and more brittle than the rest of the stretched film 2.

The stretched film 2 typically has a slow axis in the stretching direction described above. The slow axis of the stretched film 2 may be misaligned in the width direction. More specifically, the direction of the slow axis of the stretched film 2 is likely to deviate from the desired angle at the width direction ends. Typically, the axis misalignment is not substantially manifested in the width direction center of the stretched film 2, and becomes larger as it approaches the width direction ends. In the illustrated example of the stretched film 2, the slow axis is substantially parallel to the stretching direction described above at the width direction center (for example, the axis misalignment is less than 0°±1°). In addition, at the width direction ends of the stretched film 2, the slow axis may intersect with the stretching direction described above (for example, the axis misalignment is 1° to 3°).

C. First Cutting Step and Recovery Step As shown in Fig. 1, in the first cutting step, both ends including the grip marks 41 of the clip are cut from the stretched film 2, typically by a cutting device 7. In one embodiment, the stretched film 2 is transported in the longitudinal direction so as to pass through the cutting device 7. This allows the stretched film 2 to be cut continuously. The stretched film 2 is preferably subjected to the first cutting step without coming into contact with a roller member such as a transport roller.

The cutting device 7 may have any suitable configuration. In the illustrated example, the cutting device 7 includes a gear cutter 71 and an opposing roller 72. The gear cutter 71 and the opposing roller 72 face each other. Each of the gear cutter 71 and the opposing roller 72 is rotatable. The gear cutter 71 can form a first cutting line 21 in the stretched film 2 passing between the gear cutter 71 and the opposing roller 72 (see FIG. 2).

As shown in FIG. 2, the cutting device 7 typically forms two first cutting lines 21 on the stretched film 2. The first cutting lines 21 extend along the longitudinal direction of the stretched film 2. The two first cutting lines 21 are formed at a predetermined distance from each other in the width direction of the stretched film 2, and each of the two first cutting lines 21 is formed at a predetermined distance from the gripping mark 41 of the clip in the width direction of the stretched film 2.

Through the above steps, two first end films 4 are obtained from the stretched film 2, which correspond to both ends of the stretched film 2 in the width direction. Each of the two first end films 4 includes a clip gripping mark 41. Furthermore, the stretched film 2 from which the two first end films 4 have been cut is configured as an intermediate film 3. That is, in the first cutting step, the stretched film 2 is separated into two first end films 4 and an intermediate film 3. Each of the two first end films 4 and the intermediate film 3 has an elongated shape.

The width of the first end film 4 is not particularly limited as long as the first end film 4 includes the entire gripping mark 41 of the clip. When the width of the stretched film 2 is taken as 100%, the width of the first end film 4 is, for example, 0.1% or more, preferably 0.5% or more, and, for example, 30% or less, preferably 25% or less, more preferably 10% or less, even more preferably 5% or less, and particularly preferably 1% or less. The width of the first end film 4 is, for example, 2 mm or more, preferably 10 mm or more, and, for example, 600 mm or less, preferably 500 mm or less, more preferably 200 mm or less, even more preferably 100 mm or less, and particularly preferably 20 mm or less.
When the width of the first end film is equal to or greater than the lower limit, the first end film can stably include the entire gripping mark of the clip. When the width of the first end film is equal to or less than the upper limit, the size of the intermediate film can be sufficiently secured, and thus the yield of the product film, which will be described later, can be improved.

The area ratio of the clip grip marks 41 on the first end film 4 is, for example, 1% or more, preferably 5% or more, and for example, 95% or less, preferably 75% or less. When the area ratio of the grip marks is within the above range, the first end film can be given a flexibility that allows it to be recovered, and the first end film can be recovered smoothly.

Such a first end film 4 is collected by the collection process described above. The first end film 4 may be discarded without being reused.

D. Second Cutting Step As shown in FIG. 1, the second cutting step is performed after the first cutting step. In the second cutting step, both widthwise ends of the intermediate film 3 obtained in the first cutting step are cut, typically by a cutting device 7. In one embodiment, the intermediate film 3 is transported in the longitudinal direction so as to pass through the cutting device 7. This allows the intermediate film 3 to be cut continuously. The cutting device 7 used in the second cutting step can be described in the same manner as the cutting device 7 used in the first cutting step. Note that the cutting device 7 used in the first cutting step may be distinguished as the first cutting device 7a, and the cutting device 7 used in the second cutting step may be distinguished as the second cutting device 7b.

As shown in FIG. 3, the second cutting device 7b typically forms two second cutting lines 22 on the intermediate film 3. The second cutting lines 22 extend along the longitudinal direction of the intermediate film 3. The two second cutting lines 22 are formed at a predetermined distance from each other in the width direction of the intermediate film 3, and each of the two second cutting lines 22 is formed at a predetermined distance from the widthwise edge of the intermediate film 3.

As a result of the above, two second end films 5 corresponding to both ends of the intermediate film 3 in the width direction are obtained from the intermediate film 3. Furthermore, the intermediate film 3 from which the two second end films 5 have been cut is configured as the product film 6. That is, in the second cutting process, the intermediate film 3 is separated into the two second end films 5 and the product film 6. Each of the two second end films 5 may include a portion of the intermediate film 3 in which the axial misalignment described above is relatively large. This makes it possible to reduce the axial misalignment in the product film 6. Each of the two second end films 5 and the product film 6 has an elongated shape.

The width of the second end film 5 is not particularly limited. The width of the second end film 5 is typically larger than the width of the first end film 4. The ratio of the width of the second end film 5 to the width of the first end film 4 (width of the second end film/width of the first end film) exceeds 1.0, for example, and is preferably 1.1 or more, more preferably 10 or more, and even more preferably 20 or more, and is, for example, 30 or less, preferably 25 or less.
When the width of the second end film/the width of the first end film is within the above range, the proportion of the second end film, which is relatively easy to reuse, can be increased.

The width of the second end film 5 is, when the dimension in the width direction of the intermediate film 3 is taken as 100%, for example, 0.5% or more, preferably 1.0% or more, more preferably 5.0% or more, and even more preferably 10.0% or more, and for example, 30% or less, preferably 25% or less, and more preferably 20% or less. The dimension in the width direction of the second end film 5 is, for example, 10 mm or more, preferably 20 mm or more, more preferably 100 mm or more, and even more preferably 200 mm or more, and for example, 600 mm or less, preferably 500 mm or less, and more preferably 300 mm or less.
When the width of the second end film is equal to or greater than the lower limit, the second end film can include a sufficient portion where the axial misalignment is relatively large, so that the axial misalignment in the product film can be reduced more stably.

E. First Winding Step As shown in FIG. 1, the second end film 5 obtained in the second cutting step is wound by the first winding member 8 in the first winding step described above. The first winding member 8 is typically rotatable about an axis line substantially parallel to the width direction of the second end film 5. Although FIG. 1 illustrates one first winding member 8 for convenience, in reality, the same number of first winding members 8 as the number of second end films 5 (i.e., two) are provided. The first winding member 8 may have any appropriate configuration. The first winding member 8 typically has a cylindrical shape.

The conveying speed (line speed) of the second end film 5 from the second cutting device 7b toward the first winding member 85 is, for example, 50 mm/s or more, preferably 80 mm/s or more, and, for example, 1600 mm/s or less, preferably 1150 mm/s or less. When the line speed of the second end film is in the above range, the tension applied to the second end film can be adjusted to a suitable range, and breakage of the second end film can be further suppressed.

F. Second Winding Step The product film 6 obtained in the second cutting step is collected by any suitable means. In one embodiment, the end film manufacturing method further includes a second winding step in which the second winding member 9 winds up the product film 6. In the second winding step, the product film 6 is wound around the second winding member 9 and collected. This makes it possible to manufacture a product film roll 101 in which the product film 6 is wound in a roll shape. In the product film roll 101, the product film 6 is layered in the radial direction of the second winding member 9. The second winding member 9 can be described in the same manner as the first winding member 8.

The product film 6 is typically configured as a retardation film having a slow axis. The refractive index of the product film 6 satisfies the relationship of nx>ny.
In one embodiment, the product film 6 functions as a λ/4 plate. When the product film functions as a λ/4 plate, the in-plane retardation Re(550) of the product film 6 is, for example, 100 nm to 180 nm, and preferably 135 nm to 155 nm.
In another embodiment, the retardation film functions as a λ/2 plate. When the product film functions as a λ/2 plate, the in-plane retardation Re(550) of the product film 6 is, for example, 230 nm to 310 nm, preferably 250 nm to 290 nm.

The wavelength dependence of the product film 6 is not particularly limited. The product film 6 preferably exhibits wavelength dependence of reverse dispersion. The Re(450)/Re(550) of the product film 6 is preferably 0.8 or more and less than 1.0, more preferably 0.8 to 0.95. The Re(550)/Re(650) of the product film 6 is preferably 0.8 or more and less than 1.0, more preferably 0.8 to 0.97.

The absolute value of the photoelastic coefficient of the product film 6 is, for example, 2×10 ⁻¹² (m ² /N) to 100×10 ⁻¹² (m ² /N), and preferably 5×10 ⁻¹² (m ² /N) to 50×10 ⁻¹² (m ² /N).

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The methods for measuring each property are as follows. Note that, unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on mass.

<<Preparation of Stretched Film>>
<Preparation Example 1>
In the same manner as in Production Example 9 of JP 2022-150732 A, a resin film made of a PC resin was prepared, and the resin film was stretched to prepare a stretched film made of a PC resin. The width of the stretched film was 2000 mm. The thickness of the stretched film was 48 μm. Clip grip marks were formed on both ends of the stretched film in the width direction.

<Preparation Example 2>
A stretched film made of PET was prepared in the same manner as in Production Example 9 of JP-A-2022-150732, except that the resin film made of PC resin was changed to a resin film made of PET (manufactured by Toray Industries, Inc., product number "50U48"). The width of the stretched film was 2000 mm. The thickness of the stretched film was 50 μm. A clip grip mark was formed on each of both ends in the width direction of the stretched film.

<Preparation Example 3>
A stretched film made of an acrylic resin was prepared in the same manner as in Production Example 9 of JP-A-2022-150732, except that the resin film made of a PC resin was changed to a resin film made of an acrylic resin (manufactured by Kaneka Corporation, product name "HTX-Z"). The width of the stretched film was 2000 mm. The thickness of the stretched film was 40 μm. A gripping mark of a clip was formed on each of both ends in the width direction of the stretched film.

<Preparation Example 4>
A stretched film made of a COP-based resin was prepared in the same manner as in Production Example 9 of JP-A-2022-150732, except that the resin film made of a PC-based resin was changed to a resin film made of a COP-based resin (manufactured by Zeon Corporation, product number "ZF16"). The width of the stretched film was 2000 mm. The thickness of the stretched film was 40 μm. A clip grip mark was formed on each of both ends in the width direction of the stretched film.

[Example 1]
The stretched film made of PC resin obtained in Preparation Example 1 was cut by a slitter (first cutting device) to separate it into two first end films and an intermediate film. The width of each of the two first end films was 10 mm (0.5% when the width of the stretched film was 100%). The width of the intermediate film was 1980 mm. The first end films were then packed into a collection box and collected.

The intermediate film was then transported to a slitter (second cutting device) and separated into two second end films and a product film. The width of each of the two second end films was 240 mm (12.1% of the width of the intermediate film taken as 100%). The width of the product film was 1500 mm.

Then, the second end film was wound up by the cylindrical first winding member. The line speed of the second end film was 350 mm/s. The number of windings (number of layers in the end film roll) was 7,000. The collected second end film was then visually observed. The results are shown in Table 1.

[Example 2]
The first end film and the second end film were collected in the same manner as in Example 1, except that the stretched film made of the PC resin obtained in Preparation Example 1 was replaced with the stretched film made of the PET obtained in Preparation Example 2. The collected second end film was visually observed to check for breakage. The results are shown in Table 1.

[Example 3]
The end film was collected in the same manner as in Example 1, except that the stretched film made of the PC resin obtained in Preparation Example 1 was replaced with the stretched film made of the acrylic resin obtained in Preparation Example 3. The collected second end film was visually observed to check for breakage. The results are shown in Table 1.

[Example 4]
The end film was collected in the same manner as in Example 1, except that the stretched film made of the PC resin obtained in Preparation Example 1 was replaced with the stretched film made of the COP resin obtained in Preparation Example 4. The collected second end film was visually observed to check for breakage. The results are shown in Table 1.

[Comparative Example 1]
The stretched film made of PC resin obtained in Preparation Example 1 was cut by a slitter (first cutting device) to separate it into two end films and a product film, and the second cutting step was not performed. The width of each of the two end films was 250 mm. The width of the product film was 1500 mm.

Next, an attempt was made to wind up the end film using a cylindrical winding member. However, the end film broke. The results are shown in Table 1. The line speed of the end film was 350 mm/s.

[Comparative Example 2]
The stretched film made of the PC resin obtained in Preparation Example 1 was cut by a slitter (first cutting device) to separate it into two end films and a product film. The width of each of the two end films was 250 mm. The width of the product film was 1500 mm.

The end film was then transported to a slitter (second cutting device) and separated into a first end film and a second end film. The width of the first end film was 0.5 mm. The width of the second end film was 249.5 mm. However, breakage was confirmed in the first end film and/or the second end film discharged from the second cutting device. The results are shown in Table 1.

[evaluation]
As is clear from Table 1, by first cutting the first end film including the clip gripping marks from the stretched film and then cutting the second end film from the intermediate film, it is possible to prevent breakage of each of the first end film and the second end film (especially the second end film), and to smoothly recover (manufacture) these end films.

The edge film manufacturing method of the present invention can produce edge films that can be reused as raw materials for various industrial products. The edge films are particularly suitable for use as recycled resin raw materials for optical films.

REFERENCE SIGNS LIST 1 resin film 2 stretched film 3 intermediate film 4 first end film 41 clip grip mark 5 second end film 6 product film 8 winding member

Claims (2)

a step of stretching a long resin film in a direction intersecting with a longitudinal direction while holding both ends of the long resin film in a width direction with clips to prepare a stretched film;
cutting each of the two end portions including the gripping marks of the clip from the stretched film to separate the stretched film into a first end film including the gripping marks and an intermediate film;
and cutting each of both widthwise ends of the intermediate film to separate it into a second end film and a product film .
A method for manufacturing an edge film , wherein the ratio of the width of the second edge film to the width of the first edge film is 1.1 or greater . The method for manufacturing an end film according to claim 1, further comprising a step of winding up the second end film with a winding member.

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