Method of manufacturing an end-film roll

Abstract

Provided is a method for manufacturing an end film roll in which end film breakage is suppressed when the end film roll is wound. The method for manufacturing an end film roll according to an embodiment of the present invention includes the following steps: a step of producing a stretched film by stretching a resin film in a direction intersecting a longitudinal direction of the resin film in a state in which both end portions in a width direction of the resin film are held by a clip; a step of cutting both end portions of a holding trace including the clip from the stretched film to obtain an end film including the holding trace; and a step of winding the end film by a winding member. The end film has a first end portion in which the holding trace is located and a second end portion on the opposite side of the first end portion in the width direction. In the step of winding the end film by the winding member, the second end portion is in contact with the winding member, and the first end portion is located away from the winding member.

Description

Technical Field

[0001] This invention relates to a method for manufacturing end film rolls. Background Technology

[0002] Stretch films, widely used in various industrial products, are manufactured by stretching a resin film. For example, a method for manufacturing a stretch film has been proposed, in which the resin film is stretched in a direction intersecting the length of the strip while being held by clamps at both ends in the width direction (see, for example, Patent Document 1). In such a method, clamping traces are formed at both ends of the stretch film in the width direction. Therefore, generally, the ends containing these clamping traces are cut off from the stretch film and discarded.

[0003] In recent years, from the perspective of reducing environmental impact, there has been a desire to reuse waste generated during the manufacturing of various industrial products. Therefore, in the stretch film manufacturing method described in Patent Document 1, the efficient utilization of the cut ends of the stretch film as end films has been studied. However, if the end films are wound up for recycling, they sometimes break, making successful recycling impossible.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 7096940 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The present invention was made to solve the above-mentioned prior art problems, and its main objective is to provide a method for manufacturing an end film roll that can suppress the breakage of the end film during winding and can smoothly manufacture the end film roll.

[0009] Methods for solving problems

[0010] [1] The method for manufacturing an end film roll according to an embodiment of the present invention includes the following steps: a step of preparing a stretched film by stretching the resin film in a direction intersecting the elongated direction while holding both ends of the elongated resin film in the width direction with clamps; a step of cutting the stretched film from both ends containing the clamps to obtain an end film containing the clamps; and a step of winding the end film with a winding member. The end film has a first end in the width direction where the clamps are located and a second end on the opposite side of the first end. In the step of winding the end film with the winding member, the second end is in contact with the winding member, and the first end is located away from the winding member.

[0011] [2] In the method for manufacturing the end film roll described in [1] above, the winding member may also include a shaft and a roller. The roller is disposed on the shaft. The diameter of the roller is larger than that of the shaft. In the process of the winding member winding the end film, the second end may also contact the roller, and the first end faces the shaft with a gap between them.

[0012] [3] According to the manufacturing method of the end film roll described in [1] above, the winding member may also have a conical surface whose diameter decreases as it moves from one end toward the other end in the axial direction. In the process of the winding member winding the end film, the second end may also contact the conical surface, and the first end faces the conical surface with a gap relative to the portion with a diameter smaller than the contact portion of the second end in the conical surface.

[0013] Invention Effects

[0014] According to embodiments of the present invention, it is possible to suppress end film breakage during winding of the end film, and to smoothly manufacture end film rolls. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating a method for manufacturing an end film roll according to one embodiment of the present invention.

[0016] Figure 2 yes Figure 1 A top view of the stretch membrane.

[0017] Figure 3 It is used for explanation Figure 1 A schematic top view of the process of winding the end film by the winding component.

[0018] Figure 4 It is used for explanation Figure 1 A schematic cross-sectional view of the winding component for winding the end film.

[0019] Figure 5 This is a schematic cross-sectional view illustrating a method for manufacturing an end film roll according to another embodiment of the present invention.

[0020] Explanation of symbols

[0021] 1. Resin film

[0022] 2. Stretch film

[0023] 3. Clamping marks

[0024] 4. End membrane

[0025] 5. Winding component

[0026] 100 end film roll Detailed Implementation

[0027] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments. Furthermore, to make the description clearer, the accompanying drawings sometimes schematically represent the width, thickness, shape, etc., of various parts compared to the embodiments, but these are merely examples and do not limit the interpretation of the present invention.

[0028] (Definitions of terms and symbols)

[0029] The definitions of terms and symbols used in this specification are as follows.

[0030] (1) Refractive index (nx, ny, nz)

[0031] “nx” is the refractive index in the direction where the refractive index is maximum (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis (i.e., the fast axis direction), and “nz” is the refractive index in the thickness direction.

[0032] (2) In-plane phase difference (Re)

[0033] “Re(λ)” is the in-plane phase difference measured at 23°C using light with a wavelength of λ nm. For example, “Re(550)” is the in-plane phase difference measured at 23°C using light with a wavelength of 550 nm. When the thickness of the layer (film) is set to d (nm), Re(λ) is obtained using the formula: Re(λ)=(nx-ny)×d.

[0034] (3) Angle

[0035] Unless otherwise specified, when referring to angles in this instruction manual, the angles include both clockwise and counterclockwise angles.

[0036] A. An overview of the manufacturing method for the end film roll

[0037] Figure 1 This is a schematic configuration diagram illustrating a method for manufacturing an end film roll according to one embodiment of the present invention; Figure 2 yes Figure 1 A top view of the stretch membrane; Figure 3 It is used for explanation Figure 1 A schematic top view of the process of winding the end film using the winding component; Figure 4 It is used for explanation Figure 1 A schematic cross-sectional view of the winding component for winding the end film.

[0038] The method for manufacturing the end film roll according to an embodiment of the present invention sequentially includes a stretching step, a cutting step, and a first winding step (see reference). Figure 1In the stretching process, while holding the two ends of the elongated resin film 1 in the width direction with clamps, the resin film 1 is stretched in a direction intersecting the elongated direction to prepare a stretched film 2. In the cutting process, the two ends containing the clamps 3 are cut from the stretched film 2 to obtain an end film 4 containing the clamps 3. In the first winding process, the winding member 5 winds up the end film 4. The end film 4 has a first end E1 where the clamps 3 are located and a second end E2 on the opposite side of the first end E1 in the width direction (see reference). Figure 3 In the first winding process, the second end E2 of the end film 4 contacts the winding member 5, and the first end E1 of the end film 4 is located away from the winding member 5 (see reference). Figure 4 ).

[0039] The inventors discovered that when the end film is wound up and recycled, the clamping marks become the starting point of cracks and the cause of end film breakage. Therefore, they conducted in-depth research on the winding method of the end film and found that the end film is wound up stably when the clamping marks are not in contact with the winding member. Specifically, since the winding member 5 winds up the end film 4 with the second end E2 in contact with the winding member 5 and the first end E1 (i.e., the clamping marks 3) away from the winding member 5, breakage of the end film 4 can be suppressed, and the end film 4 can be wound up stably. As a result, an end film roll 100 formed by the winding member 5 winding the end film 4 can be manufactured smoothly. In other words, the end film 4 can be wound into a roll and recycled smoothly. That is, the method for manufacturing the end film roll according to the embodiments of the present invention is, in other words, an end film recycling method.

[0040] The recycled end-film (end-film roll) is a separately circulated item that can be used industrially, typically as a raw material for recycled resin.

[0041] Recycled resin raw materials can be used in the manufacture of any suitable resin products. Examples of resin products include optical films such as retardation films; and packaging materials made of thermoplastic resins such as polyethylene terephthalate (PET) and nylon. Among these resin products, optical films are preferred, and retardation films are more preferred. That is, the recycled end film can be used as a raw material for optical films (typically retardation films).

[0042] The following details each step of the manufacturing process for the end film roll.

[0043] B. Stretching process

[0044] like Figure 1As shown, in the stretching process, the elongated resin film 1 is stretched using the stretching device 7.

[0045] B-1. Resin film of the object being stretched

[0046] In this specification, resin film 1 refers to the film prior to the stretching process. Any suitable film can be used as resin film 1. As described above, resin film 1 has a strip shape. The dimensions of resin film 1 in each direction can be any suitable value. The width of resin film 1 (the dimension in the direction orthogonal to the strip direction) is, for example, 500 mm or more, preferably 700 mm or more, for example, 2500 mm or less, preferably 2000 mm or less. The thickness of resin film 1 is, for example, 40 μm or more, preferably 60 μm or more, for example, 200 μm or less, preferably 180 μm or less.

[0047] Examples of resin materials constituting resin film 1 include polycarbonate resins, polyvinyl acetal resins, cycloolefin resins, (meth)acrylic resins, cellulose ester resins, cellulose resins, polyester resins, polyester carbonate resins, olefin resins, and polyurethane resins. It should be noted that (meth)acrylic resins refer to acrylic resins and / or methacrylic resins. These resin materials can be used alone or in combination.

[0048] Among the resin materials constituting the resin film 1, polycarbonate (PC) resins, cyclic olefin (COP) resins, (meth)acrylic resins, and polyester resins (typically polyethylene terephthalate (PET)) are preferred, and PC resins are more preferred. Using such resin materials allows for more stable recycling of the end film during the first winding process.

[0049] Examples of PC-based resins include those containing structural units derived from dihydroxy compounds. Specific examples of dihydroxy compounds 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-cyclohexylphenyl)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 structural units derived from the aforementioned dihydroxy compounds, PC resins may also contain structural units derived from dihydroxy compounds such as isosorbide, isomannitol, isoidulitol, spirodiol, dioxanediol, diethylene glycol (DEG), triethylene glycol (TEG), polyethylene glycol (PEG), cyclohexanediethanol (CHDM), tricyclodecanediethanol (TCDDM), and bisphenols.

[0050] Details of the aforementioned PC-based resins are described, for example, in Japanese Patent Application Publication No. 2012-67300 and Japanese Patent No. 3325560. The descriptions in these patent documents are incorporated herein by reference.

[0051] B-2. Tensioning device

[0052] In one embodiment, the resin film 1 is conveyed along the elongated direction in a manner similar to that of passing through the stretching device 7. Therefore, the resin film 1 can be conveyed and stretched simultaneously, enabling the continuous production of the stretched film 2.

[0053] Although not shown, the stretching device 7 includes clamps that hold the ends of the resin film 1 in the width direction. The stretching device 7 is typically a tenter frame stretching device. With the two ends of the resin film 1 in the width direction held (typically clamped) by the clamps, the stretching device 7 stretches the resin film 1 in a direction intersecting the longitudinal direction. The stretching direction can be substantially orthogonal to the longitudinal direction of the resin film 1 (e.g., 90° ± 1° relative to the longitudinal direction), or it can be a direction intersecting both the longitudinal and width directions of the resin film 1.

[0054] 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.

[0055] Therefore, as Figure 2 As shown, a long strip-shaped stretch film 2 is prepared. The stretching ratio in the width direction (width of the stretch film / width of the resin film) in the stretching process is, for example, 1.1 or more, preferably 1.5 or more, for example, 6.0 or less, preferably 4.0 or less.

[0056] Clamping marks 3 are formed at both ends of the stretch film 2 in the width direction. The clamping marks 3 are harder and more brittle than the parts of the stretch film 2 other than the clamping marks 3.

[0057] The stretch membrane 2 typically has a slow axis in the stretching direction described above. The slow axis of the stretch membrane 2 sometimes deviates from its axis in the width direction. More specifically, the direction of the slow axis of the stretch membrane 2 tends to deviate from the desired angle at its ends in the width direction. This deviation is typically not noticeable at the center of the stretch membrane 2 in the width direction, but becomes larger closer to the ends in the width direction. In the stretch membrane 2 illustrated in the figure, at the center of the width direction, the slow axis is substantially parallel to the stretching direction described above (e.g., the axis deviation is less than 0° ± 1°). Furthermore, at the ends of the stretch membrane 2 in the width direction, the slow axis may also intersect the stretching direction described above (e.g., the axis deviation is 1° to 3°).

[0058] C. Cutting process

[0059] like Figure 1 As shown, in the cutting process, the two ends containing the clamping marks 3 of the stretch film 2 are typically cut from the stretch film 2 using the cutting device 8. In one embodiment, the stretch film 2 is conveyed along the strip direction in a manner that it passes through the cutting device 8. Thus, the stretch film 2 can be cut continuously. The stretch film 2 is preferably supplied to the cutting process without contacting roller components such as conveying rollers.

[0060] The cutting device 8 can have any suitable configuration. In the example shown, the cutting device 8 includes a toothed blade 81 and an opposing roller 82. The toothed blade 81 and the opposing roller 82 face each other. The toothed blade 81 and the opposing roller 82 are each rotatable. The toothed blade 81 can form a cutting line 21 (see reference) on the stretch film 2 passing between the toothed blade 81 and the opposing roller 82. Figure 2 ).

[0061] like Figure 2 As shown, the cutting device 8 typically forms two cutting lines 21 on the stretch film 2. The cutting lines 21 extend along the longitudinal direction of the stretch film 2. The two cutting lines 21 are formed with a predetermined interval between them in the width direction of the stretch film 2, and the two cutting lines 21 are also formed with a predetermined interval between them and the clamping traces 3 in the width direction of the stretch film 2.

[0062] Through the above, two end films 4 corresponding to the two ends in the width direction of the stretch film 2 are obtained from the stretch film 2. Each of the two end films 4 contains a clamping mark 3. Furthermore, the stretch film 2, with the two end films 4 cut, constitutes a product film 6. That is, in the cutting process, the stretch film 2 is typically separated into two end films 4 and a product film 6. The two end films 4 and the product film 6 are each strip-shaped.

[0063] The width of the end film 4 is not particularly limited as long as the end film 4 includes the entire holding trace 3 of the clip. When the width of the stretch film 2 is set to 100%, the width of the end film 4 is, for example, 0.5% or more, preferably 1.0% or more, more preferably 5.0% or more, further preferably 10.0% or more, for example, 30% or less, preferably 25% or less, more preferably 20% or less. The width of the end film 4 is, for example, 10 mm or more, preferably 20 mm or more, more preferably 100 mm or more, further preferably 200 mm or more, for example, 600 mm or less, preferably 500 mm or less, more preferably 300 mm or less.

[0064] If the width of the end film is above or above the aforementioned lower limit, the end film can stably contain the entire clamping traces, and the end film can contain the portion of the stretch film with relatively large axial deviation. As a result, the clamping traces remaining in the product film can be suppressed, and the axial deviation in the product film can be reduced. If the width of the end film is below or above the aforementioned upper limit, the yield of the product film can be improved.

[0065] The area ratio of the clamping traces 3 in the end membrane 4 is, for example, 1% or more, preferably 5% or more, for example, 95% or less, preferably 75% or less.

[0066] If the area occupied by the holding trace is within the above-mentioned range, the portion of the stretch film with relatively large axial deviation can be sufficiently included in the end film. Therefore, it is possible to stably reduce the axial deviation in the product film.

[0067] D. First winding process

[0068] like Figure 1 As shown, in the first winding process, the winding member 5 winds up the end film 4, which has been cut from the stretch film 2 by the cutting device 8. This allows for continuous recovery of the end film 4, enabling the manufacture of the end film roll 100. The winding member 5 is typically capable of rotating about an axis substantially parallel to the width direction of the end film 4. It should be noted that in... Figure 1 For convenience, only one winding member 5 is shown in the figure, but in reality, the winding member 5 and the end film 4 are arranged in the same number (i.e., 2).

[0069] like Figure 3 As shown, the end membrane 4 has a first end E1 located in the width direction with a clamping trace 3 and a second end E2 on the opposite side of the first end E1.

[0070] In the first winding process, the end film 4 is wound by the winding member 5 with at least the second end E2 of the end film 4 in contact with the winding member 5 and the first end E1 of the end film 4 (i.e., the holding trace 3) away from the winding member 5. The end film 4 is stacked and recovered radially along the winding member as winding progresses (see reference). Figure 4 ).

[0071] When the width of the end film 4 is set to 100%, the width of the portion of the end film 4 that contacts the winding member 5 is, for example, 30% or more, preferably 50% or more, for example, 95% or less, preferably 80% or less. If the width of the contact portion of the end film is at or above the aforementioned lower limit, the winding member can stably wind up the end film. If the width of the contact portion of the end film is at or below the aforementioned upper limit, it is possible to stably prevent the clamping marks from contacting the winding member.

[0072] The conveying speed (linear speed) of the end film 4 from the cutting device 8 toward the winding member 5 is, for example, 50 mm / s or more, preferably 80 mm / s or more, for example, 1600 mm / s or less, preferably 1150 mm / s or less. If the linear speed of the end film is within the above range, the tension applied to the end film can be adjusted to a suitable range, and the breakage of the end film can be further suppressed.

[0073] D-1. Winding component

[0074] The winding member 5 can have any suitable configuration. For example... Figure 4As shown, in one embodiment, the take-up member 5 includes a shaft 51 and a roller portion 52. Hereinafter, the take-up member 5 including the shaft 51 and the roller portion 52 will sometimes be referred to as a descending roller.

[0075] Shaft 51 is typically cylindrical in shape.

[0076] A roller portion 52 is disposed on the shaft 51. In the example shown, the roller portion 52 is disposed on the circumferential surface of the shaft 51 such that both ends of the shaft 51 are exposed. The roller portion 52 is typically cylindrical in shape. The roller portion 52 has a larger diameter than the shaft 51.

[0077] The outer diameter of the roller portion 52 is, for example, 50 mm or more and 200 mm or less. Materials for the roller portion 52 include, for example, easily processed materials; more specifically, acrylonitrile-butadiene-styrene copolymer resin (ABS), fiber-reinforced plastic (FRP), etc.

[0078] In the example shown, the shaft 51 and the roller 52 are constructed as separate parts, but the shaft 51 and the roller 52 can also be constructed as a single unit.

[0079] In this embodiment, during the first winding process, at least the second end E2 of the end film 4 is in contact with the outer peripheral surface of the roller 52, and the first end E1 (i.e., the holding trace 3) of the end film 4 is located away from the roller 52 and faces each other with a gap relative to the shaft 51.

[0080] like Figure 5 As shown, in another embodiment, the take-up member 5 has a tapered surface 53 whose diameter decreases as it moves from one end toward the other in the axial direction. Hereinafter, the take-up member 5 having the tapered surface 53 will sometimes be referred to as a tapered roller.

[0081] The tapered roller 5 is typically shaped like a truncated cone. In the tapered roller 5, the maximum outer diameter is, for example, 70 mm or more and 200 mm or less, and the minimum outer diameter is, for example, 40 mm or more and 100 mm or less. Examples of materials used for the tapered roller 5 include ABS and FRP.

[0082] The cone angle of the cone surface 53 is, for example, 15° or more, preferably 20° or more, more preferably 30° or more, for example, 60° or less, preferably 50° or less, more preferably 45° or less. If the cone angle is within the above range, the contact between the clamp's gripping trace and the conical roller can be stably suppressed during the first winding process.

[0083] In this embodiment, during the first winding process, at least the second end E2 of the end film 4 comes into contact with the conical surface 53, and the first end E1 (i.e., the holding trace 3) of the end film 4 faces each other with a gap relative to the portion with a diameter smaller than the contact portion of the second end E2 in the conical surface 53.

[0084] E. Second winding process

[0085] like Figure 1 As shown, the product film 6 obtained in the above-described cutting process is recycled by any suitable means. In one embodiment, the method for manufacturing the end film roll further includes a second winding step in which the winding member 9 winds the product film 6. In the second winding step, the product film 6 is wound onto the winding member 9 and recycled. Therefore, it is possible to manufacture a product film roll 101 in which the product film 6 is wound into a roll. The winding member 9 may have any suitable configuration.

[0086] The product film 6 is typically configured as a phase retardation film with a slow axis. The refractive index of the product film 6 shows a relationship of nx > ny.

[0087] In one embodiment, the article film 6 functions as a λ / 4 plate. When the article film functions as a λ / 4 plate, the in-plane phase difference Re(550) of the article film 6 is, for example, 100 nm to 180 nm, preferably 135 nm to 155 nm.

[0088] In another embodiment, the phase difference film functions as a λ / 2 plate. When the product film functions as a λ / 2 plate, the in-plane phase difference Re(550) of the product film 6 is, for example, 230 nm to 310 nm, preferably 250 nm to 290 nm.

[0089] There are no particular limitations on the wavelength dependence of the article film 6. The article film 6 preferably exhibits an anti-dispersion wavelength dependence. The Re(450) / Re(550) of the article film 6 is preferably 0.8 or more and less than 1.0, more preferably 0.8 to 0.95. Furthermore, the Re(550) / Re(650) of the article film 6 is preferably 0.8 or more and less than 1.0, more preferably 0.8 to 0.97.

[0090] The absolute value of the photoelastic coefficient of the product film 6 is, for example, 2 × 10⁶. -12 (m 2 / N)~100×10 -12 (m 2 / N), preferably 5×10 -12 (m 2 / N)~50×10 -12 (m 2 / N).

[0091] Example

[0092] The present invention will now be specifically described through examples, but the present invention is not limited to these examples. The methods for measuring each characteristic are described below. It should be noted that, unless otherwise specified, "parts" and "%" in the examples and comparative examples refer to mass measurements.

[0093] <<Preparation of Stretch Membranes>>

[0094] <Preparation Example 1>

[0095] Following the same procedure as in Manufacturing Example 9 of Japanese Patent Application Publication No. 2022-150732, a resin film made of PC-based resin was prepared, and the resin film was stretched to prepare a stretched film made of PC-based resin. The width of the stretched film was 2000 mm. The thickness of the stretched film was 48 μm. Clamping marks were formed at both ends of the stretched film in the width direction.

[0096] <Preparation Example 2>

[0097] Except for changing the resin film made of PC-based resin to a resin film made of PET (manufactured by Toray Industries, part number "50U48"), a stretch film made of PET was prepared in the same manner as in Manufacturing Example 9 of Japanese Patent Application Publication No. 2022-150732. The width of the stretch film is 2000 mm. The thickness of the stretch film is 50 μm. Clamping marks are formed at both ends of the stretch film in the width direction.

[0098] <Preparation Example 3>

[0099] Except for changing the resin film made of PC-based resin to a resin film made of acrylic resin (manufactured by KANEKA Co., Ltd., product name "HTX-Z"), a stretch film made of acrylic resin was prepared by operating in the same manner as in Manufacturing Example 9 of Japanese Patent Application Publication No. 2022-150732. The width of the stretch film is 2000 mm. The thickness of the stretch film is 40 μm. Clamping marks are formed at both ends of the stretch film in the width direction.

[0100] <Preparation Example 4>

[0101] Except for changing the resin film made of PC-based resin to a resin film made of COP-based resin (manufactured by ZEON Corporation, Japan, part number "ZF16"), a stretch film made of COP-based resin was prepared by operating in the same manner as in Manufacturing Example 9 of Japanese Patent Application Publication No. 2022-150732. The width of the stretch film is 2000 mm. The thickness of the stretch film is 40 μm. Clamping marks are formed at both ends of the stretch film in the width direction.

[0102] [Example 1]

[0103] The stretch film made of PC resin obtained in Preparation Example 1 was cut using a slitting machine (cutting device) to separate it into two end films and a finished product film. The width of each of the two end films was 250 mm (12.5% ​​when the width of the stretch film was set to 100%). The width of the finished product film was 1500 mm.

[0104] Next, prepare Figure 3 and Figure 4 The step-reducing roller shown is made of ABS. The outer diameter of the roller is 92.5 mm. It should be noted that in Table 1, the angle of 90° between the circumferential surface of the shaft and the end face of the roller is recorded as the cone angle in the step-reducing roller.

[0105] Next, with at least the second end of the end film in contact with the outer peripheral surface of the roller, and the first end of the end film (i.e., the holding trace) away from the roller and facing each other with a gap relative to the axis, the end film is wound onto the step-down roller. The width of the contact portion of the end film with the roller is 200 mm (80% when the width of the end film is set to 100%). The linear speed of the end film is 350 mm / s. The number of windings (the number of layers in the end film roll) is 7000. Afterwards, the recovered end film is visually inspected to confirm the presence or absence of breakage. The results are shown in Table 1.

[0106] [Examples 2 and 3]

[0107] In addition to changing the step-down roller to a tapered roller with the cone angle shown in Table 1 (see Table 1 for reference) Figure 5 Except for Example 1, the end film is recycled in the same manner. The tapered roller is made of ABS. The maximum outer diameter of the tapered roller is 92.5 mm and the minimum outer diameter is 85 mm or less.

[0108] More specifically, the end film is wound onto a tapered roller with at least the second end of the end film in contact with the conical surface, and the first end of the end film (i.e., the holding trace) facing each other with a gap relative to the portion of the end film whose diameter is smaller than that of the contact portion of the second end in the conical surface. The width of the portion of the end film in contact with the conical surface is 100 mm (40% when the width of the end film is set to 100%). The linear speed of the end film is 350 mm / s. The number of windings (the number of layers in the end film roll) is 7000. Afterwards, the recovered end film is visually inspected to confirm the presence or absence of breakage. The results are shown in Table 1.

[0109] [Example 4]

[0110] Except that the stretch film made of PC resin obtained in Preparation Example 1 was replaced with the stretch film made of PET obtained in Preparation Example 2, the same procedure as in Example 1 was followed to recycle the end films. The recycled end films were visually inspected to confirm the presence or absence of breakage. The results are shown in Table 1.

[0111] [Example 5]

[0112] Except that the stretch film made of PC-based resin obtained in Preparation Example 1 was replaced with the stretch film made of acrylic resin obtained in Preparation Example 3, the same procedure as in Example 1 was followed to recover the end films. The recovered end films were visually inspected to confirm the presence or absence of breakage. The results are shown in Table 1.

[0113] [Example 6]

[0114] Except that the stretch film made of PC-based resin obtained in Preparation Example 1 was replaced with the stretch film made of COP-based resin obtained in Preparation Example 4, the same procedure as in Example 1 was followed to recover the end films. The recovered end films were visually inspected to confirm the presence or absence of breakage. The results are shown in Table 1.

[0115] [Comparative Example 1]

[0116] The same procedure as in Example 1 was followed, and the stretch film made of PC resin obtained in Preparation Example 1 was cut to obtain two end films and an article film.

[0117] Next, prepare a cylindrical take-up roller. The take-up roller is made of ABS. The outer diameter of the take-up roller is 92.5 mm.

[0118] Next, with the entire end film, including the clamping marks, in contact with the outer peripheral surface of the take-up roller, an attempt was made to wind the end film. However, a breakage occurred in the end film. The results are shown in Table 1. The linear speed of the end film was 350 mm / s.

[0119] [Comparative Example 2]

[0120] In addition to changing the step-down roller to a tapered roller with the cone angle shown in Table 1 (see Table 1 for reference) Figure 5 Apart from Example 1, the same procedure was followed to attempt to recycle the end membrane. However, breakage occurred in the end membrane. The results are shown in Table 1.

[0121] It should be noted that in the comparative example, the cone angle was insufficient, and during the winding of the end film, the entire end film, including the clamping traces, came into contact with the cone surface.

[0122] Table 1

[0123]

[0124] [evaluate]

[0125] As shown in Table 1, it is known that if the end film is wound up in a state where the gripping traces of the clamps contained in the end film are not in contact with the winding member, end film breakage can be suppressed and the end film can be stably wound into a roll.

[0126] Industrial availability

[0127] The method for manufacturing end-film rolls of the present invention enables the production of end-film rolls that can be reused as raw materials for various industrial products. End-film recycled as end-film rolls is particularly suitable for use as a recycled resin raw material for optical films.

Claims

1. A method for manufacturing an end-film roll, comprising the following steps: The process of preparing a stretched film is to hold the two ends of a long strip of resin film in the width direction with clamps and stretch the resin film in a direction that intersects the length direction. The process of cutting off both ends of the stretch film containing the clamping marks to obtain an end film containing the clamping marks; and The process of winding the end film using a winding component. The end membrane has a first end in the width direction where the holding trace is located and a second end on the opposite side of the first end. The winding member includes: a shaft; and a roller portion disposed on the shaft and having a diameter larger than the shaft. In the process of the winding member winding the end film, the second end contacts the roller, and the first end faces the roller with a gap relative to the shaft; or The winding member has a tapered surface whose diameter decreases as it moves from one end toward the other in the axial direction. In the process of the winding member winding the end film, the second end contacts the conical surface, and the first end faces the conical surface with a gap relative to the portion with a diameter smaller than the contact portion of the second end in the conical surface.

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