Method for manufacturing recycled chip

Abstract

To provide a method for manufacturing a recycle chip which can smoothly manufacture a recycled chip that has excellent conveyance property and is suitably usable as a raw material of a recycled pellet.SOLUTION: A method for manufacturing a recycle chip includes the steps of: stretching a long resin film in a direction crossing a long direction, in a state in which both ends in a width direction of the resin film are gripped by a clip, and preparing a stretched film; cutting each of both ends including a gripping mark of the clip from the stretched film, and obtaining an end film including the gripping mark; and crushing the end film into a plurality of small pieces having averages of maximum lengths of 1 mm or more and 25 mm or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing recycled chips.

Background Art

[0002] The stretched film widely used in various industrial products is manufactured by stretching a resin film. For example, a method for manufacturing a stretched film has been proposed in which both end portions in the width direction of a long resin film are gripped by clips and the resin film is stretched in a direction intersecting the long direction (see, for example, Patent Document 1). In such a method for manufacturing a stretched film, gripping marks of the clips are generated at both end portions in the width direction of the stretched film. Therefore, generally, the end portions including the gripping marks are cut off from the stretched film and discarded. In recent years, from the viewpoint of reducing the environmental load, reuse of waste generated during the manufacture of various industrial products has been desired. Therefore, in the method for manufacturing a stretched film described in Patent Document 1, it has been considered to collect the end portions cut from the stretched film as end films and effectively utilize them. However, the collected end films are easily broken and may be difficult to transport.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention has been made to solve the above conventional problems, and its main object is to provide a method for manufacturing recycled chips that can smoothly manufacture recycled chips having excellent transportability and being suitably used as raw materials for recycled pellets.

Means for Solving the Problems

[0005] [1] The method for manufacturing a recycled chip according to an embodiment of the present invention includes a step of preparing a stretched film by stretching a long resin film in a direction intersecting the longitudinal direction while gripping both end portions in the width direction of the long resin film with clips; a step of cutting each of both end portions including the gripping marks of the clips from the stretched film to obtain an end film including the gripping marks; and a step of pulverizing the end film into a plurality of small pieces having an average maximum length of 1 mm or more and 25 mm or less.

Effects of the Invention

[0006] According to an embodiment of the present invention, a recycled chip having excellent transportability and suitable for use as a raw material for recycled pellets can be smoothly manufactured.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments. Further, for the sake of clarity of explanation, the drawings may schematically show the width, thickness, shape, etc. of each part as compared with the embodiments, but this is merely an example and does not limit the interpretation of the present invention.

[0009] (Definition of Terms and Symbols) The definitions of the terms and symbols in this specification are as follows. (1) Refractive Index (nx, ny, nz) "nx" is the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-plane retardation (Re) "Re(λ)" is the in-plane retardation measured with light of wavelength λ nm at 23°C. For example, "Re(550)" is the in-plane retardation measured with light of wavelength 550 nm at 23°C. Re(λ) can be obtained by the formula: Re(λ) = (nx - ny) × d, where d (nm) is the thickness of the layer (film). (3) Angle When referring to an angle in this specification, unless otherwise specified, the angle includes angles in both the clockwise and counterclockwise directions.

[0010] A. Outline of the method for manufacturing a recycled chip Figure 1 is a schematic configuration diagram for explaining a method for manufacturing a recycled chip according to one embodiment of the present invention; Figure 2 is a plan view of the stretched film of Figure 1; Figure 3 is a schematic view of a recycled chip obtained by crushing the end film of Figure 1.

[0011] The method for manufacturing a recycled chip according to an embodiment of the present invention includes a stretching step, a cutting step, and a crushing step in this order (see Figure 1). In the stretching step, with both end portions in the width direction of the long resin film 1 held by clips, the resin film 1 is stretched in a direction intersecting the long direction to prepare a stretched film 2. In the cutting step, both end portions including the gripping marks 22 of the clips are cut from the stretched film 2 to obtain an end film 3 including the gripping marks 22. In the crushing step, the end film 3 is crushed into a plurality of small pieces to obtain recycled chips 9 (see Figure 3). The average of the maximum lengths L of the plurality of recycled chips 9 (small pieces) is 1.0 mm or more, preferably 2.0 mm or more, more preferably 4.0 mm or more, 25 mm or less, preferably 20 mm or less, more preferably 10.0 mm or less, still more preferably 8.0 mm or less, and particularly preferably 6.0 mm or less. The inventors have discovered that when transporting the end film, the gripping marks of the clips become the starting points of cracks and cause the breakage of the end film. Therefore, they considered pulverizing the end film including the gripping marks of the clips into small pieces and transporting the obtained recycled chips. As a result, they found that if the average of the maximum lengths of the recycled chips is equal to or greater than a specific value, the recycled chips can be transported smoothly. Specifically, the end film 3 including the gripping marks 22 of the clips was pulverized into a plurality of small pieces such that the average of the maximum length L is equal to or greater than the above lower limit. The recycled chips 9 thus obtained are suppressed from sticking to the transport member (typically a pipe) and can be transported smoothly. Further, since the average of the maximum length L of the recycled chips 9 is equal to or less than the above upper limit, it is possible to suppress the mixing of air bubbles into the recycled pellets manufactured using the recycled chips as a raw material.

[0012] As described above, the manufactured recycled chips have excellent transportability and can be suitably used as a raw material for recycled pellets. The recycled chips are articles that can be circulated independently and are industrially applicable. The recycled pellets can be used in the manufacture of any suitable resin products. Examples of the resin products include optical films such as retardation films; packaging materials composed of thermoplastic resins such as polyethylene terephthalate (PET) and nylon. Among these resin products, optical films are preferably mentioned, and retardation films are more preferably mentioned. That is, the recycled chips can be suitably used in the manufacture of optical films (typically retardation films).

[0013] Hereinafter, the details of each step of the method for manufacturing recycled chips will be described.

[0014] B. Stretching step As shown in FIG. 1, in the stretching step, the long resin film 1 is stretched typically by a stretching device 7.

[0015] B-1. Resin film to be stretched The resin film 1 refers to the film before the stretching process in this specification. Any appropriate film can be adopted as the resin film 1. As described above, the resin film 1 has a long shape. Appropriate values can be adopted for the dimensions of the resin film 1 in each direction. 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.

[0016] Examples of the resin material constituting the 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. Note that the (meth)acrylic resin refers to an acrylic resin and / or a methacrylic resin. These resin materials can be used alone or in combination.

[0017] Among the resin materials constituting the resin film 1, preferably, polycarbonate (PC) resins, cycloolefin (COP) resins, (meth)acrylic resins, and polyester resins (typically polyethylene terephthalate (PET)) are mentioned, and more preferably PC resins are mentioned. When such resin materials are used, the end film can be stably conveyed to the crushing device.

[0018] Examples of the PC resin include a PC resin containing a structural unit derived from a dihydroxy compound. 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, 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 the structural unit derived from the above dihydroxy compound, the PC-based resin may contain a structural unit derived from a dihydroxy compound such as isosorbide, isomannide, isoidide, spiroglycol, dioxane glycol, diethylene glycol (DEG), triethylene glycol (TEG), polyethylene glycol (PEG), cyclohexanedimethanol (CHDM), tricyclodecanedimethanol (TCDDM), and bisphenols.

[0019] Details of the above-mentioned PC-based resin are described, for example, in JP-A-2012-67300 and Japanese Patent No. 3325560. The descriptions of the patent documents are incorporated herein by reference.

[0020] B-2. Stretching device In one embodiment, the resin film 1 is conveyed in the longitudinal direction so as to pass through the stretching device 7. Therefore, the resin film 1 can be stretched while being conveyed, and the stretched film 2 can be continuously prepared.

[0021] Although not shown, the stretching device 7 includes clips capable of gripping the end portions in the width direction of the resin film 1. The stretching device 7 is typically a tenter stretching device. The stretching device 7 stretches the resin film 1 in a direction intersecting the longitudinal direction while gripping (typically sandwiching) each of the both end portions in the width direction of the resin film 1 with clips. The stretching direction may be a direction substantially orthogonal 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.

[0022] Details of the stretching process are described, for example, in Japanese Patent No. 7096940, JP-A-2004-226686, and WO 2007 / 111313. The descriptions of the patent documents are incorporated herein by reference.

[0023] As a result, as shown in FIG. 2, a long stretch film 2 is prepared. The stretching ratio in the width direction in the stretching step (width of the stretch film / width of the 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.

[0024] At each of both end portions in the width direction of the stretch film 2, a gripping mark 22 of a clip is formed. The gripping mark 22 of the clip is harder and more brittle than the portions other than the gripping mark 22 in the stretch film 2.

[0025] Typically, the stretch film 2 has a slow axis in the stretching direction described above. The slow axis of the stretch film 2 may be offset in the width direction. More specifically, the direction of the slow axis of the stretch film 2 is likely to deviate from a desired angle at the width direction end portions. Typically, such an axis deviation does not substantially occur at the center portion in the width direction of the stretch film 2, and becomes larger as it approaches the width direction end portions. In the stretch film 2 in the illustrated example, at the center portion in the width direction, the slow axis is substantially parallel to the stretching direction described above (for example, the axis deviation is less than 0°±1°). Also, at the width direction end portions of the stretch film 2, the slow axis may intersect the stretching direction described above (for example, the axis deviation is 1° to 3°).

[0026] C. Cutting Step As shown in FIG. 1, in the cutting step, both end portions including the gripping mark 22 of the clip are cut from the above-described stretch film 2, typically by a cutting device 5. In one embodiment, the stretch film 2 is conveyed in the longitudinal direction so as to pass through the cutting device 5. As a result, the stretch film 2 can be continuously cut. The stretch film 2 is preferably subjected to the cutting step without contacting a roller member such as a conveying roller.

[0027] The cutting device 5 can have any suitable configuration. In the illustrated example, the cutting device 5 includes a gear cutter 51 and an opposing roller 52. The gear cutter 51 and the opposing roller 52 face each other. Each of the gear cutter 51 and the opposing roller 52 is rotatable. The gear cutter 51 can form a cutting line 21 in the stretched film 2 passing between the gear cutter 51 and the opposing roller 52 (see FIG. 2).

[0028] As shown in FIG. 2, the cutting device 5 typically forms two cutting lines 21 in the stretched film 2. The cutting lines 21 extend along the longitudinal direction of the stretched film 2. The two cutting lines 21 are formed at a predetermined interval from each other in the width direction of the stretched film 2, and each of the two cutting lines 21 is formed at a predetermined interval from the gripping mark 22 of the clip in the width direction of the stretched film 2.

[0029] As described above, two end films 3 corresponding to both end portions in the width direction of the stretched film 2 are obtained from the stretched film 2. Each of the two end films 3 includes the gripping mark 22 of the clip. Also, the stretched film 2 from which the two end films 3 are cut is configured as a product film 4. That is, in the cutting process, the stretched film 2 is typically separated into two end films 3 and a product film 4. Each of the two end films 3 and the product film 4 has a long shape.

[0030] The width of the end film 3 is not particularly limited as long as the end film 3 includes the entire gripping mark 22 of the clip. When the width of the stretched film 2 is taken as 100%, the width of the end film 3 is, for example, 0.5% or more, preferably 1.0% or more, more preferably 5.0% or more, still more preferably 10.0% or more, and for example, 30% or less, preferably 25% or less, more preferably 20% or less. The width of the end film 3 is, for example, 10 mm or more, preferably 20 mm or more, more preferably 100 mm or more, still more preferably 200 mm or more, and for example, 600 mm or less, preferably 500 mm or less, more preferably 300 mm or less. When the width of the end film is equal to or greater than the above lower limit, the entire gripping mark of the clip can be stably included in the end film, and a portion of the stretched film with a relatively large axial deviation can be included in the end film. As a result, it is possible to suppress the remaining gripping mark of the clip on the product film and reduce the axial deviation in the product film. When the width of the end film is equal to or less than the above upper limit, the yield of the product film can be improved.

[0031] The area ratio occupied by the gripping mark of the clip in the end film 3 is, for example, 1% or more, preferably 5% or more, and for example, 95% or less, preferably 75% or less. When the area ratio occupied by the gripping mark is within the above range, a portion of the stretched film with a relatively large axial deviation can be sufficiently included in the end film. Therefore, the axial deviation in the product film can be more stably reduced.

[0032] D. Crushing Process As shown in FIG. 1, in the crushing process, the end film 3 cut from the stretched film 2 is typically crushed into small pieces of the above size by a crushing device 8. As a result, the end film 3 can be continuously crushed, and a plurality of recycled chips 9 can be smoothly manufactured.

[0033] The end film 3 is typically subjected to the crushing process without being wound around a winding member. The end film 3 is conveyed to the crushing device 8 by any suitable method. Examples of the conveying method of the end film 3 include air conveyance. Note that two end films 3 may be conveyed to one crushing device 8 for crushing, or each of the two end films 3 may be conveyed to a separate crushing device 8 for crushing. The crushing device 8 is not particularly limited and may have any suitable configuration. A typical example of the crushing device 8 is a multi-cutter.

[0034] In one embodiment, in the crushing process, the end film 3 is crushed step by step. Specifically, first, the end film 3 is primary crushed (rough cut) into a plurality of small pieces with an average maximum length of, for example, 50 mm to 100 mm. Next, the obtained primary crushed pieces are further crushed to obtain a plurality of recycled chips 9 (small pieces) with an average maximum length L within the above range. Thereby, it is possible to suppress the occurrence of jams in the crushing device.

[0035] As shown in FIG. 3, each of the plurality of recycled chips 9 has a predetermined thickness because it is manufactured by crushing the end film 3. The recycled chip 9 may have any appropriate shape when viewed in the thickness direction. Examples of the shape of the recycled chip 9 when viewed in the thickness direction include a triangle, a quadrilateral, a pentagon, a polygon with six or more sides, a circle, and an ellipse. Preferably, a polygon is mentioned, and more preferably, a quadrilateral is mentioned.

[0036] The mass of each recycled chip 9 is, for example, 5 mg or more, preferably 10 mg or more, and for example, 100 mg or less, preferably 70 mg or less. The bulk density of the plurality of recycled chips 9 is, for example, 5 mg / cm 3 or more, preferably 10 mg / cm 3 or more, and for example, 50 mg / cm 3 or less, preferably 30 mg / cm 3 or less. If the bulk density of the recycled chip is equal to or higher than the above lower limit, when manufacturing recycled pellets from the recycled chip, it is possible to stably suppress the mixing of air bubbles into the recycled pellets. If the bulk density of the recycled chip is equal to or lower than the above upper limit, it is possible to further improve the transportability of the recycled chip.

[0037] As described above, the recycled chip 9 can be used for manufacturing recycled pellets. In one embodiment, the recycled chip 9 is pneumatically conveyed to a pellet manufacturing apparatus. More specifically, the recycled chip 9 is conveyed to the pellet manufacturing apparatus by a pneumatic conveying device. The pneumatic conveying device can have any suitable configuration. The pneumatic conveying device may be a pressure conveying system or a suction conveying system. Although not shown, the pneumatic conveying device includes a hopper, piping, and an air flow generator. The recycled chip 9 can be loaded into the hopper. The piping connects the hopper and the destination (typically a pellet manufacturing apparatus). The air flow generator can generate an air flow from the hopper to the destination inside the piping. The air flow generator can have any suitable configuration. Examples of the air flow generating device include a blower and a compressor. Even when the recycled chip is transported by such a pneumatic conveying device, since the average of the maximum lengths of the recycled chips is equal to or greater than the above lower limit, it is possible to prevent the recycled chips from sticking to the pneumatic conveying device, and the recycled chips can be smoothly transported.

[0038] The pellet manufacturing apparatus can have any suitable configuration. The pellet manufacturing apparatus may be a strand cut method or a hot cut method. The pellet manufacturing apparatus melts the supplied recycled chips to manufacture recycled pellets having a predetermined size. In the recycled pellets manufactured in this way, since the average of the maximum lengths of the recycled chips used as raw materials is equal to or less than the above upper limit, the bubble ratio is sufficiently reduced.

[0039] The bubble ratio of the recycled pellets is, for example, 10% by volume or less, preferably 3% by volume or less, and more preferably 0% by volume. The bubble ratio can be measured by observation and analysis using a microscope. If the bubble ratio of the recycled pellets is equal to or less than the above upper limit, the recycled pellets can be suitably used for manufacturing various resin products (typically optical films). The recycled pellets may be larger than the recycled chips, may be smaller than the recycled chips, or may be of the same size as the recycled chips. The recycled pellets can have any suitable shape. In one embodiment, the recycled pellets have a cylindrical shape. The average of the maximum length of the recycled pellets is, for example, 1.0 mm or more and 5.0 mm or less. The mass per recycled pellet is, for example, 5 mg or more and 25 mg or less.

[0040] E. Winding Process As shown in FIG. 1, the product film 4 obtained in the above-described cutting process is recovered by any suitable means. In one embodiment, the method for manufacturing recycled chips further includes a winding process in which a winding member 6 winds the product film 4. In the winding process, the product film 4 is wound around the winding member 6 for recovery. Therefore, a product film roll 100 in which the product film 4 is wound in a roll shape can be manufactured.

[0041] The winding member 6 can have any suitable configuration. The winding member 6 has, for example, a cylindrical shape. The winding member 6 is typically rotatable about an axis substantially parallel to the width direction of the end film 3.

[0042] The product film 4 is typically configured as a retardation film having a slow axis. The refractive indices of the product film 4 exhibit the relationship nx > ny. In one embodiment, the product film 4 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 4 is, for example, 100 nm to 180 nm, 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 4 is, for example, 230 nm to 310 nm, preferably 250 nm to 290 nm.

[0043] The wavelength dependence of the product film 4 is not particularly limited. The product film 4 preferably exhibits an inverse dispersion wavelength dependence. Re(450) / Re(550) of the product film 4 is preferably 0.8 or more and less than 1.0, more preferably 0.8 to 0.95. Also, Re(550) / Re(650) of the product film 4 is preferably 0.8 or more and less than 1.0, more preferably 0.8 to 0.97.

[0044] The absolute value of the photoelastic coefficient of the product film 4 is, for example, 2×10 -12 (m 2 / N) to 100×10 -12 (m 2 / N), preferably 5×10 -12 (m 2 / N) to 50×10 -12 (m 2 / N).

Examples

[0045] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. The measurement methods for each property are as follows. Unless otherwise specified, "parts" and "%" in the examples and comparative examples are based on mass. Also, the measurement methods for each property in the examples and comparative examples are as follows.

[0046] (1) Bulk density of recycled chips The bulk density of the recycled chips obtained in the examples and comparative examples was measured using a hydrometer. The results are shown in Table 1.

[0047] (2) Conveyability of recycled chips The recycled chips obtained in the examples and comparative examples were put into a suction-type air conveying device, and the conveyability of the recycled chips was observed by the amount of recycled chips conveyed with respect to the amount of end material input, and evaluated according to the following criteria. The results are shown in Table 1. 〇 (excellent): 95% by mass or more △ (good): 80% by mass or more and less than 95% by mass × (infeasible): less than 80% by mass

[0048] (3) Bubbles in recycled pellets produced from recycled chips Recycled pellets were produced from the recycled chips obtained in the examples and comparative examples by melt extrusion. The obtained recycled pellets were observed under a microscope, and the bubbles in the recycled pellets were evaluated according to the following criteria. The results are shown in Table 1. 〇 (Excellent): The proportion of bubbles in the total pellet volume is 10% or less × (Unacceptable): The proportion of bubbles in the total pellet volume exceeds 10%

[0049] <<Preparation of Stretched Film>> <Preparation Example 1> In the same manner as in Production Example 9 of JP-A-2022-150732, a resin film composed of a PC-based resin was prepared, and the resin film was stretched to prepare a stretched film composed of a PC-based resin. The width of the stretched film was 2000 mm. The thickness of the stretched film was 48 μm. Gripping marks of clips were formed at both ends in the width direction of the stretched film.

[0050] <Preparation Example 2> A stretched film composed of PET was prepared in the same manner as in Production Example 9 of JP-A-2022-150732, except that the resin film composed of a PC-based resin was changed to a resin film composed 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. Gripping marks of clips were formed at both ends in the width direction of the stretched film.

[0051] <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. Gripping marks of clips were formed at both ends in the width direction of the stretched film.

[0052] <Preparation Example 4> A stretched film made of a COP 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 a COP resin (product number "ZF16" manufactured by Nippon Zeon Co., Ltd.). The width of the stretched film was 2000 mm. The thickness of the stretched film was 40 μm. Gripping marks of clips were formed at both ends in the width direction of the stretched film.

[0053] [Examples 1, 2 and Comparative Examples 1, 2] The stretched film made of the PC resin obtained in Preparation Example 1 was cut by a slitter (cutting device) and separated into two end films and a product film. The width of each of the two end films was 250 mm (12.5% when the width of the stretched film was taken as 100%). The width of the product film was 1500 mm.

[0054] Next, the end films were crushed into small pieces by a multi-cutter (crushing device) to obtain a plurality of recycled chips. Table 1 shows the average of the maximum lengths of the recycled chips in each example and each comparative example.

[0055] [Example 3] A plurality of recycled chips were obtained in the same manner as in Example 1, except that the stretched film made of the PC resin obtained in Preparation Example 1 was changed to the stretched film made of PET obtained in Preparation Example 2.

[0056] [Example 4] A plurality of recycled chips were obtained in the same manner as in Example 2, except that the stretched film made of the PC-based resin obtained in Preparation Example 1 was changed to a stretched film made of the PET obtained in Preparation Example 2.

[0057] [Example 5] A plurality of recycled chips were obtained in the same manner as in Example 1, except that the stretched film made of the PC-based resin obtained in Preparation Example 1 was changed to a stretched film made of the acrylic-based resin obtained in Preparation Example 3.

[0058] [Example 6] A plurality of recycled chips were obtained in the same manner as in Example 1, except that the stretched film made of the PC-based resin obtained in Preparation Example 1 was changed to a stretched film made of the COP-based resin obtained in Preparation Example 4.

[0059] [Comparative Example 3] A plurality of recycled chips were obtained in the same manner as in Comparative Example 2, except that the stretched film made of the PC-based resin obtained in Preparation Example 1 was changed to a stretched film made of the PET obtained in Preparation Example 2.

[0060] [Table 1]

[0061] [Evaluation] As is clear from Table 1, it can be seen that if the average of the maximum lengths of the recycled chips is equal to or greater than the above lower limit, the transportability of the recycled chips can be improved, and if the average of the maximum lengths of the recycled chips is equal to or less than the above upper limit, the mixing of air bubbles into the recycled pellets can be suppressed. [Industrial Applicability]

[0062] The manufacturing method of the recycled chip of the present invention can manufacture a recycled chip that can be reused as a raw material for various industrial products. The recycled chip is particularly suitably used for recycled pellets used in the manufacture of optical films.

Explanation of symbols

[0063] 1 Resin film 2 Stretched film 22 Gripping mark of clip 3 End film 9 Recycled chip

Claims

【Claim 1】 A step of preparing a stretched film by stretching a long resin film in a direction intersecting the longitudinal direction while gripping both end portions in the width direction of the long resin film with clips; A step of cutting both end portions including the gripping traces of the clips from the stretched film to obtain end films including the gripping traces; A step of pulverizing the end films into a plurality of small pieces having an average maximum length of 1 mm or more and 25 mm or less, the method for manufacturing recycled chips.

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