Film roll manufacturing method

Abstract

To provide a film roll manufacturing method capable of reducing defects (fish-eyes, scratches, convex-concave defects located near a knurl part) generated in a film.SOLUTION: A film roll manufacturing method for manufacturing a film roll by winding a long-length film around a winding core, comprises the steps of: winding the long-length film on a touch roll; and winding up the long-length film wound on the touch roll around the winding core. The touch roll pushes the long-length film in the middle of manufacturing toward a center of the winding core. The long-length film has knurl parts each having a convex-concave part at both ends in a width direction of the long-length film. A planar shape when viewing the convex-concave part from a thickness direction of the long-length film includes a plurality of corners each having an angle of 80° to 100°. The number of the corners in the knurl part is 40 / cm2 or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Film is typically manufactured as a long roll, then wound onto a suitable core to form a film roll, which is then stored and transported. In recent years, maintaining the quality of these film rolls has become a challenge. One method to address this challenge is to provide knurled sections with uneven surfaces at both ends in the width direction of the long roll. A known method for winding a long roll with knurled sections is to wind the long roll onto a touch roll, and then wind the long roll wound onto the touch roll onto a core. It is also known to press the film roll with the touch roll during the winding process (see Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2016-132537 [Overview of the project] [Problems that the invention aims to solve]

[0004] When a long film provided with caulking portions at both end portions in the width direction is wound around a winding core to form a film roll, the uneven portions of the caulking portions contact the upper layer film with high pressure, so that both end portions in the axial direction of the film roll where the caulking portions are overlapped are restricted in movement. On the other hand, an air layer is formed between the long films wound around each other at the central portion in the axial direction of the film roll excluding both end portions in the axial direction of the film roll. This air layer suppresses the occurrence of the phenomenon (blocking) in which the wound films adhere to each other, but the air layer makes the film easier to move. As a result, when the film roll is transported, the films may rub against each other to cause scratches, or the film roll may be recessed in the radial direction, and defects called "bumps" with a diameter of about 10 mm or less may be formed in the film. In addition, unevenness may occur near the boundary between both end portions in the axial direction of the film roll where the movement is restricted and the central portion in the axial direction of the film roll where the movement is easy, and uneven defects may be formed near the caulking portion of the film.

[0005] Therefore, there is a need for a method for manufacturing a film roll that can reduce these defects (bumps, scratches, and uneven defects near the caulking portion) generated in the film.

Means for Solving the Problem

[0006] As a result of intensive studies to solve the above problems, the present inventor has found that the above problems can be solved by winding a long film having the number of specific uneven shapes per unit area of the caulking portion within a predetermined range by a specific method, and has completed the present invention. That is, the present invention provides the following.

[0007] [1] A method for manufacturing a film roll, comprising winding a long film around a winding core to manufacture a film roll, wherein the manufacturing method includes a step of winding the long film around a touch roll, and a step of winding the long film wound around the touch roll around the winding core, wherein the touch roll presses the film roll being manufactured toward the center of the winding core, The long film has knurled portions with concavo-convex portions at both ends in the width direction of the long film, The planar shape of the concavo-convex portions as viewed from the thickness direction of the long film includes a plurality of corner portions having an angle of 80° to 100°, and the number of the corner portions in the knurled portion is 40 pieces / cm 2 or more, a method for manufacturing a film roll. [2] The load for pressing the film roll during the manufacture of the touch roll toward the center of the core is 5 N / m to 150 N / m, the method for manufacturing a film roll according to [1]. [3] The tension for winding the long film wound around the touch roll around the core is 80 N / m to 150 N / m, the method for manufacturing a film roll according to [1] or [2]. [4] The average height of the concavo-convex portions is 0.5 μm to 8 μm, the method for manufacturing a film roll according to any one of [1] to [3]. [5] The peripheral surface portion of the touch roll is formed of a material having a rubber hardness of 55 degrees or more, the method for manufacturing a film roll according to any one of [1] to [4]. [6] The concavo-convex portions are formed by irradiation with laser light, the method for manufacturing a film roll according to any one of [1] to [5].

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a method for manufacturing a film roll that can reduce defects (bumps, scratches, and concavo-convex defects near the knurled portion) occurring in the film.

Brief Description of the Drawings

[0009] [Figure 1] FIG. 1 is a front view schematically showing a winding device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view schematically showing a state of a long film according to an embodiment of the present invention as viewed from the thickness direction of the long film. [Figure 3]Figure 3 is a schematic plan view showing the planar shape of one of the uneven portions of a long film according to one embodiment of the present invention, as viewed from the thickness direction of the long film. [Figure 4] Figure 4 is a schematic, enlarged plan view showing an example of a corner of an uneven portion of a long film according to one embodiment of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view showing a cross-section of a linear uneven portion of a long film according to one embodiment of the present invention, cut by a plane perpendicular to the direction of extension of the uneven portion. [Figure 6] Figure 6 is a schematic partial cross-sectional view showing a film roll that can be obtained by a film roll manufacturing method according to one embodiment of the present invention. [Figure 7] Figure 7 is a schematic partial cross-sectional view showing a film roll related to a comparative example. [Figure 8] Figure 8 is a schematic plan view showing the planar shape of the uneven portion 500 formed in Comparative Example 1. [Figure 9] Figure 9 is a schematic diagram showing an example of a winding device for implementing the manufacturing method according to the comparative example. [Modes for carrying out the invention]

[0010] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and can be modified and implemented as appropriate without departing from the scope of the claims and equivalents of the present invention. The components of the embodiments shown below can be combined as appropriate. In addition, in the figures, the same reference numerals are used for the same components, and their descriptions may be omitted.

[0011] In the following description, "long film" refers to a film having a length of five times or more its width, preferably 10 times or more its width, and specifically a film long enough to be wound into a roll for storage or transport. There is no particular upper limit to the length of a long film; for example, it may be 100,000 times or less its width.

[0012] In the following description, unless otherwise specified, the planar shape of the uneven portion formed on the film refers to the shape of the uneven portion as viewed from the thickness direction of the film.

[0013] In the following explanation, "thickness direction" refers to the thickness direction of the film unless otherwise specified.

[0014] In the following explanation, unless otherwise specified, "(meth)acrylic" is a term that encompasses "acrylic," "methacrylic," and combinations thereof, and "(meth)acrylate" is a term that encompasses "acrylate," "methacrylate," and combinations thereof.

[0015] In the following explanation, unless otherwise specified, the range "AA~BB" includes the boundary values ​​"AA" and "BB".

[0016] [1. Overview of the film roll manufacturing method] A method for manufacturing a film roll according to one embodiment of the present invention is a method for manufacturing a film roll by winding a long film onto a winding core. The method for manufacturing a film roll according to this embodiment includes the steps of winding the long film onto a touch roll and winding the long film wound onto the touch roll onto the winding core. The touch roll pushes the film roll, which is in the process of being manufactured, toward the center of the winding core. The long film has knurled sections with uneven surfaces at both ends in the width direction of the long film. The planar shape of the uneven portion, as viewed from the thickness direction of the long film, includes multiple corners having angles of 80° to 100°. The number of corners in the knurled portion is 40 per cm. 2 That's all.

[0017] The touch roll tends to reduce "bumps" and scratches on the film by pressing the film roll toward the center of the core during manufacturing. The number of corners with an angle of 80° to 100° in the knurled section is 40 per cm.2 As a result of the above, the unevenness defects near the knurled area tend to be reduced. A method for manufacturing a film roll according to one embodiment of the present invention, by having the above configuration, can reduce "bumps," scratches, and unevenness defects near the knurled portion that occur in the film.

[0018] [2. Structure of film roll manufacturing equipment] Figure 1 is a schematic front view showing a winding device 1000 according to one embodiment of the present invention. As shown in Figure 1, the winding device 1000 according to this embodiment is a film roll manufacturing device for winding a long film 1 to produce a film roll 1300, and comprises a winding core 1110, a winding core motor 1120 as a rotational drive device for the winding core 1110, a touch roll 1130, and an arm 1140 as a position adjustment device for the touch roll 1130.

[0019] The winding core 1110 is a member that is rotatable in the circumferential direction of the winding core 1 so as to be able to wind a long film 1. Typically, a cylindrical or cylindrical member having a length equal to or greater than the width of the long film 1 is used as the winding core 1110. A winding core motor 1120 capable of rotating the winding core 1110 is connected to this winding core 1110 by a power transmission mechanism such as a gear mechanism (not shown).

[0020] The touch roll 1130 is a roll that is rotatable in the circumferential direction of the touch roll 1130 and movable in the radial direction of the winding core 1110. The touch roll 1130 is positioned parallel to and opposite the winding core 1110 at the point where the long film 1 enters the winding core 1110 or the film roll 1300 in the process of being manufactured, so that it can wind the long film 1 just before it is wound onto the winding core 1110. Here, the film roll 1300 in the process of being manufactured refers to a film roll 1300 that is manufactured by winding the long film 1 onto the winding core 1110, but in which the winding of the long film 1 has not been completed. The touch roll 1130 is also positioned so as to be able to contact the outermost long film 1 of the long film 1 that has been wound onto the winding core 1110 and become part of the film roll 1300 in the process of being manufactured. Furthermore, the touch roll 1130 is provided to press the film roll 1300 in the process of being manufactured toward the center of the winding core 1110 (i.e., the rotation center of the winding core 1110) with a predetermined load. The touch roll 1130 is a single cylindrical or cylindrical member that is usually longer than or equal to the width of the long film 1, and has a constant diameter in the area where it can come into contact with the long film 1.

[0021] The circumferential portion of the touch roll 1130, including its peripheral surface, is preferably formed of a material with a rubber hardness of 55 degrees or higher. In this specification, unless otherwise specified, "rubber hardness" means the value measured using a durometer type A in accordance with JIS K6253-3. The rubber hardness of the peripheral portion is more preferably 58 degrees or higher, particularly preferably 60 degrees or higher, and preferably 90 degrees or lower. By forming the circumferential portion of the touch roll 1130 with a material having a rubber hardness within this range, the occurrence of unevenness defects near the knurled portion of the long film 1 can be effectively suppressed. Furthermore, wear of the rubber of the touch roll can be reduced.

[0022] The aforementioned touch roll 1130 is supported by an arm 1140. The arm 1140 is provided to be movable in the radial direction of the winding core 1110 so as to be able to adjust the position of the touch roll 1130 in the radial direction of the winding core 1110. In this case, the position of the arm 1140 can be set according to the amount of film 1 to be wound. Specifically, the arm 1140 is provided so as the amount of film 1 to be wound increases and the diameter of the film roll 1300 increases, it can move the touch roll 1130 in the radial direction of the winding core 1110, thereby moving the touch roll 1130 away from the winding core 1110. In addition, the arm 1140 is provided with an air cylinder, which is a biasing device (not shown), so that the touch roll 1130 attached to the arm 1140 can press the film roll 1300 in the process of being manufactured with a predetermined force.

[0023] The long film 1 according to this embodiment is wound up by the winding device 1000 described above. The winding conditions by the winding device 1000 will be described later.

[0024] [3. Embodiment of long film] Figure 2 is a schematic plan view showing a long film 1 according to one embodiment of the present invention, as viewed from the thickness direction of the long film 1. As shown in Figure 2, the long film 1 is a long film having a plurality of protrusions 10 on at least one surface 1U. These plurality of protrusions 10 are usually arranged in the longitudinal direction MD of the long film 1. The protrusions 10 are also usually provided at both ends of the long film 1 in the width direction TD. The planar shape of each protrusion 10 when viewed from the thickness direction may be different, but in this embodiment, an example is shown where the planar shape of all protrusions 10 is the same. In this embodiment, the long film 1 has a plurality of protrusions 10 at each of its ends, but in another embodiment, the long film may have a continuous single bent line of protrusions at each of its ends.

[0025] As shown in Figure 2, multiple protrusions and indentations 10 form strip-shaped knurled portions 101 extending in the longitudinal direction MD of the long film 1 at both ends of the long film 1. The width W1 of the knurled portion 101 in the width direction TD of the long film 1 is usually the distance between a straight line L1 connecting the innermost protrusions and indentations 10 in the width direction TD of the long film 1 and a straight line L2 connecting the outermost protrusions and indentations 10 in the width direction TD of the long film 1, i.e., the protrusions and indentations 10 closest to the end of the long film 1.

[0026] The width W1 of the knurled portion 101 is preferably 3 mm or more, more preferably 5 mm or more, particularly preferably 7 mm or more, preferably 20 mm or less, more preferably 17 mm or less, and particularly preferably 15 mm or less. By having a width W1 of the knurled portion 101 greater than or equal to the lower limit, blocking of the long film 1 can be effectively suppressed. Furthermore, by having a width W1 of the knurled portion 101 less than or equal to the upper limit, the long film 1 can be used for optical elements such as polarizers with good yield.

[0027] Figure 3 is a schematic plan view showing the planar shape of one of the uneven portions 10 of a long film 1 according to one embodiment of the present invention, as viewed from the thickness direction of the long film 1. As shown in Figure 3, one of the uneven portions 10 is a continuous line. The uneven portions 10 may be formed by irradiation with laser light. Therefore, one of the uneven portions 10 is usually formed as a continuous line in a single stroke, as the trace left by the movement of the laser light irradiation point. The linear uneven portions 10 formed in this way have a specific planar shape.

[0028] The planar shape of the uneven portion 10 includes a plurality of corners 131 having angles of 80° to 100°. The corners 131 are connecting portions that link two straight sections. The corners 131 may correspond to the vertices of the corner formed between the upward-sloping straight section 111 and the downward-sloping straight section 112 in Figure 3. Therefore, the corners 131 have angles θ corresponding to the direction in which the straight section 111 and the straight section 112 extend. 131 It has an angle θ. 131is usually 80° or more, preferably 85° or more, more preferably 88° or more, and is also usually in the range of 100° or less, preferably 95° or less, more preferably 92° or less. Among these, 90° is particularly preferred.

[0029] In the present embodiment, the plurality of corner portions 131 connect the upwardly right straight portion 111 and the downwardly right straight portion 112 in FIG. 3, and the plurality of corner portions 131, the plurality of straight portions 111, and the plurality of straight portions 112 form the planar shape of one endless concavo-convex portion 10. The number of corner portions 131 included in one concavo-convex portion 10 is not particularly limited. In the present embodiment, the number of corner portions 131 included in one endless concavo-convex portion 10 is 24, but it may be 24 or more (for example, 32, 40, 48, 56), or may be less than 24 (for example, 16, 8, 4). Further, in the present embodiment, the planar shape of one endless concavo-convex portion 10 includes a plurality of corner portions 131, but one concavo-convex portion may have an end-shaped polygonal planar shape, and such a polygonal planar shape may have a corner portion. The polygonal planar shape may include one corner portion or a plurality of corner portions (for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11). Furthermore, as described above, the concavo-convex portion formed in one nail portion 101 may have a planar shape that is a continuous single polygonal shape.

[0030] As shown in FIG. 3, the length L per one of the concavo-convex portions 10 in the width direction TD of the long film 1 TD and the length L per one of the concavo-convex portions 10 in the longitudinal direction MD of the long film 1 MD The ratio L TD / L MD is preferably within a specific range. Specifically, the ratio L TD / L MD is preferably 2 or more, more preferably 2.5 or more, and particularly preferably 3 or more. When the ratio L TD / L MD is within the above range, it is easy to form the concavo-convex portion 10 while suppressing the collapse of the shape. The ratio L TD / L MDThere is no particular upper limit, but it is preferably 15 or less, more preferably 13 or less, and especially preferably 10 or less.

[0031] Length L of each uneven portion 10 in the longitudinal direction MD of the long film 1 MD It is preferable that it be small. Specifically, length L MD The length L is preferably 20 mm or less, more preferably 15 mm or less, and particularly preferably 10 mm or less. MD When the size is small, the uneven surface 10 can be formed in a short time. Furthermore, the density of the uneven surface 10 in the longitudinal direction MD of the long film 1 can be increased. Length L MD The lower limit is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.5 mm or more, and especially preferably 1 mm or more.

[0032] Length L of each uneven portion 10 in the width direction TD of the long film 1 TD The ratio L mentioned above TD / L M It is preferable to set it appropriately so that it falls within the range described above. Specifically, the length L of each uneven portion 10 in the width direction TD of the long film 1. TD Preferably, it is 3 mm or more, more preferably 5 mm or more, particularly preferably 7 mm or more, preferably 20 mm or less, more preferably 17 mm or less, particularly preferably 15 mm or less.

[0033] As shown in Figure 2, it is preferable that a plurality of uneven surfaces 10 are arranged in the longitudinal direction MD of the long film 1 at a specific pitch. In this case, the pitch of the uneven surfaces 10 is preferably 0.5 mm or more, more preferably 1 mm or more, particularly preferably 1.5 mm or more, preferably 10 mm or less, more preferably 7 mm or less, and particularly preferably 5 mm or less. The pitch of the uneven surfaces 10 may be constant or may vary.

[0034] In this specification, "angle of a corner" refers to the angle at which two straight lines connected at that corner intersect (0° ≤ corner angle ≤ 180°), unless otherwise specified. A corner may appear sharp macroscopically but rounded microscopically. In such cases, unless otherwise specified, the angle of the corner is represented by the angle at which the two straight lines that intersect at the corner, when viewed macroscopically, intersect when their extensions are extended.

[0035] Figure 4 is a schematic, enlarged plan view showing an example of a corner 131 of a recessed portion 10 of a long film 1 according to one embodiment of the present invention. For example, as shown in Figure 4, when the corner 131 connecting the straight portion 111 and the straight portion 112 is rounded, when viewed macroscopically, the angle at which the two straight portions that intersect at the corner 131 (i.e., the straight portion 111 and the straight portion 112) are extended, is the angle θ of the corner 131. 131 It represents.

[0036] If the corners 131 are rounded, it is preferable that the radius of curvature R of those corners 131 falls within a specific range. This range of radius of curvature R is preferably 0.0 mm to 0.5 mm, more preferably 0.0 mm to 0.2 mm, and particularly preferably 0.0 mm to 0.1 mm. Unless otherwise specified, the radius of curvature of a corner refers to the radius of curvature R of the rounded portion of that corner, as shown in Figure 4.

[0037] The number of corners 131 with angles of 80° to 100° included in the planar shape of the uneven portion 10 as viewed from the thickness direction of the long film 1 is typically 40 corners / cm in the knurled portion 101. 2 Preferably 42 pieces / cm² 2 More preferably 45 pieces / cm 2 The above is preferable, with a minimum of 160 pieces / cm². 2 More preferably 140 pieces / cm 2 The following applies: Here, the number of corners 131 having an angle of 80° to 100° in the knurled portion 101 is equal to the unit area (1 cm²) of the knurled portion 101. 2The number of such corners 131 per ) can be calculated as the density of corners 131 in the knurled portion.

[0038] If the number of corners 131 having an angle of 80° to 100° in the knurled portion 101 is greater than or equal to the lower limit, the occurrence of defects, especially "bumps" and scratches, can be effectively suppressed. If it is less than or equal to the upper limit, the uneven portion 10 can be efficiently formed by laser light.

[0039] The inventors surmise that the mechanism by which defects can be effectively suppressed is that the number of corners 131 having an angle of 80° to 100° in the knurled portion 101 is greater than or equal to the lower limit. However, the technical scope of the present invention is not limited for the following reasons.

[0040] When forming linearly continuous uneven surfaces 10, the laser beam is irradiated onto the film while moving the laser beam irradiation point. When forming straight sections, the irradiation point moves in a straight line. On the other hand, when forming corners, the irradiation point moves so as to curve at an appropriate angle. When the irradiation point is moved in a curved manner, the irradiation time of the laser beam increases in the inner part of the direction of movement, so the energy density of the irradiated laser beam increases. Therefore, the height H (see Figure 5) of the uneven surfaces 10 increases at the corners.

[0041] In the long film 1 according to this embodiment, the knurled portion 101 has a high density of corners 131 having angles of 80° to 100°, close to 90°. Generally, the smaller the angle of a corner, the higher that corner can be. Therefore, corners 131 having angles of 80° to 100° can have a sufficiently large height. Furthermore, in the embodiment described above, the angles of the corners 131 are all within a range close to 90°, resulting in excellent uniformity. Therefore, the knurled portion 101 has many such tall and uniform corners 131.

[0042] When the long film 1 is wound into a roll, each of the protrusions 10 can support the long film 1. At this time, the corners 131 come into contact with another layer of long film 1 that is wound on top of it. Because the corners 131 are high, the contact pressure of the aforementioned contact can be increased. Furthermore, because the height of the corners 131 is uniform and is distributed with high density over a wide area of ​​the knurled portion 101, the uniformity of the contact pressure can be increased. Therefore, the gripping force between the wound long films 1 can be increased and made uniform.

[0043] As a result, the gripping force can resist the stress applied to the roll (for example, the axial stress caused by the roll's own weight) with strength and high uniformity. Therefore, the roll on which the long film 1 with the aforementioned uneven surface 10 has been wound can be deformed due to stress. Since the deformation of the roll is suppressed, the occurrence of scratches caused by the films rubbing against each other and the occurrence of "bumps" caused by the film roll being indented in the radial direction can be suppressed particularly effectively.

[0044] Figure 5 is a schematic cross-sectional view showing a cross-section of a linear uneven portion 10 of a long film 1 according to one embodiment of the present invention, cut by a plane perpendicular to the direction of extension of the uneven portion 10. As shown in Figure 5, the uneven portion 10 comprises a recess 11 and protrusions 12 provided on both sides of the recess 11. Typically, the recess 11 corresponds to the portion where the resin has been removed by thermal melting or ablation caused by laser irradiation, and the protrusions 12 correspond to the portion where the resin has been heated and fluidized by the laser irradiation and has risen up. Because the protrusions 12 protrude beyond the surface 1U of the surrounding long film 1, the effective thickness of the long film 1 is increased in this uneven portion 10. Therefore, as described above, the occurrence of defects in the long film 1 can be effectively suppressed.

[0045] The height of the uneven portion 10 refers to the height H from the surface 1U of the long film 1 to the apex of the protrusion 12 of the uneven portion 10. The height H of the uneven portion 10 may be uniform or uneven. Typically, the height H of the uneven portion 10 differs between the corners and the straight sections. Furthermore, at the corners, the height H of the inner protrusion 12 and the outer protrusion 12 may differ.

[0046] The average height of the uneven portion 10 is preferably 0.5 μm or more, more preferably 0.8 μm or more, particularly preferably 1 μm or more, preferably 8 μm or less, more preferably 7 μm or less, and particularly preferably 6 μm or less. When the average height of the uneven portion 10 is greater than or equal to the lower limit of the above range, the occurrence of defects in the long film 1 can be effectively suppressed, and moreover, winding misalignment, winding tightness, winding looseness, and meandering can usually be effectively suppressed. Furthermore, when the average height of the uneven portion 10 is less than or equal to the upper limit of the above range, the uneven portion 10 can be easily formed while suppressing deformation of the shape, and deformation of the long film 1 due to a difference in the winding diameter of the wound roll between the part where the uneven portion 10 is formed (for example, the axial end of the roll) and the other part (for example, the axial center of the roll) can be suppressed.

[0047] Here, the average height of the uneven portion 10 refers to the average height of the corners 131 having angles between 80° and 100° that are included in the uneven portion 10. As the average height of the uneven portion 10, the arithmetic mean of the heights of all the corners 131 having angles between 80° and 100° that are included in any one of the uneven portions 10 can be used.

[0048] The average height of the uneven portion 10 in the straight section is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, preferably 8 μm or less, more preferably 7 μm or less, and particularly preferably 6 μm or less. When the average height of the uneven portion 10 in the straight section is greater than or equal to the lower limit of the above range, the occurrence of defects in the long film 1 can be effectively suppressed, and furthermore, winding misalignment, winding tightness, winding looseness, and meandering can usually be effectively suppressed. Also, when the average height of the uneven portion 10 in the straight section is less than or equal to the upper limit of the above range, the uneven portion 10 can be easily formed while suppressing deformation of the shape.

[0049] The width W of the uneven portion 10 is preferably 0.1 μm or more, more preferably 0.15 μm or more, particularly preferably 0.2 μm or more, preferably 1 μm or less, more preferably 0.75 μm or less, and particularly preferably 0.5 μm or less. When the width W of the uneven portion 10 is greater than or equal to the lower limit of the above range, the occurrence of defects in the long film 1 can be effectively suppressed, and moreover, winding misalignment, winding tightness, winding looseness, and meandering can usually be effectively suppressed. Also, when the width W of the uneven portion 10 is less than or equal to the upper limit of the above range, the uneven portion 10 can be easily formed while suppressing deformation of the shape.

[0050] There are no particular restrictions on the width and thickness of the long film 1, and a width and thickness can be adopted according to the intended use. The width of the long film 1 is preferably 700 mm or more, more preferably 1000 mm or more, particularly preferably 1200 mm or more, preferably 2500 mm or less, more preferably 2200 mm or less, and particularly preferably 2000 mm or less. The thickness of the long film 1 is preferably 1 μm or more, more preferably 5 μm or more, particularly preferably 20 μm or more, preferably 1000 μm or less, more preferably 300 μm or less, and particularly preferably 150 μm or less.

[0051] When the long film 1 is used as an optical film, it is preferable that the optical film area other than the knurled portion 101 has high transparency. Specifically, the total light transmittance of the long film 1 in the aforementioned area is preferably 85% to 100%, more preferably 92% to 100%. The haze of the long film 1 in the aforementioned area is preferably 0% to 5%, more preferably 0% to 3%, and particularly preferably 0% to 2%. The total light transmittance can be measured using a turbidimeter "NDH-2000" manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K7105. The haze can also be measured using a turbidimeter "NDH2000" manufactured by Nippon Denshoku Industries Co., Ltd.

[0052] (Composition of long film) The long film 1 described above is usually a resin film. This resin film may be a stretched film or an unstretched film. Furthermore, the resin film may be a single-layer film comprising only a base layer, or a multi-layer film comprising any additional layer in combination with the base layer.

[0053] Typically, a resin-based layer is used as the base layer. Various resins can be used depending on the application of the long film, but cyclic olefin resins and (meth)acrylic resins are preferred. Films with a base layer made of cyclic olefin resin or (meth)acrylic resin generally tend to trap air during winding, and therefore are prone to defects. In contrast, the manufacturing method of this embodiment can suppress the occurrence of defects, and moreover, can effectively suppress winding misalignment, winding tightness, winding looseness, and meandering.

[0054] Cyclic olefin resins are resins containing cyclic olefin polymers. Cyclic olefin polymers exhibit excellent mechanical properties, heat resistance, transparency, low moisture absorption, dimensional stability, and lightweight properties.

[0055] A cyclic olefin polymer refers to a polymer whose structural units have an alicyclic structure. A cyclic olefin polymer can be a polymer with an alicyclic structure in the main chain, a polymer with an alicyclic structure in the side chains, a polymer with an alicyclic structure in both the main chain and side chains, or a mixture of two or more of these in any ratio. Among these, polymers with an alicyclic structure in the main chain are preferred from the viewpoint of mechanical strength and heat resistance.

[0056] Examples of alicyclic structures include saturated alicyclic hydrocarbon (cycloalkane) structures and unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structures. Of these, cycloalkane and cycloalkene structures are preferred from the viewpoint of mechanical strength and heat resistance, and cycloalkane structures are particularly preferred.

[0057] The number of carbon atoms constituting an alicyclic structure is preferably 4 or more, more preferably 5 or more, preferably 30 or less, more preferably 20 or less, and particularly preferably 15 or less per alicyclic structure. When the number of carbon atoms constituting an alicyclic structure is within this range, the mechanical strength, heat resistance, and moldability of the resin are highly balanced.

[0058] In cyclic olefin polymers, the proportion of structural units having an alicyclic structure is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. When the proportion of structural units having an alicyclic structure in a cyclic olefin polymer is within this range, transparency and heat resistance are good.

[0059] Examples of cyclic olefin polymers include norbornene polymers, monocyclic cyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and their hydrides. Among these, norbornene polymers and their hydrides are particularly preferred due to their good moldability.

[0060] Examples of norbornene polymers and their hydrides include ring-opening polymers of monomers having a norbornene structure and their hydrides; and addition polymers of monomers having a norbornene structure and their hydrides. Examples of ring-opening polymers of monomers having a norbornene structure include ring-opening homopolymers of one type of monomer having a norbornene structure, ring-opening copolymers of two or more types of monomers having a norbornene structure, and ring-opening copolymers of a monomer having a norbornene structure and other monomers copolymerizable thereto. Furthermore, examples of addition polymers of monomers having a norbornene structure include addition homopolymers of one type of monomer having a norbornene structure, addition copolymers of two or more types of monomers having a norbornene structure, and addition copolymers of a monomer having a norbornene structure and other monomers copolymerizable thereto. Among these, the hydrides of ring-opening polymers of monomers having a norbornene structure are particularly preferred from the viewpoint of moldability, heat resistance, low hygroscopicity, dimensional stability, and lightweight properties.

[0061] The weight-average molecular weight (Mw) of the cyclic olefin polymer is preferably 10,000 or more, more preferably 15,000 or more, particularly preferably 20,000 or more, preferably 100,000 or less, more preferably 80,000 or less, and particularly preferably 50,000 or less. When the weight-average molecular weight is within the above range, the mechanical strength and moldability of the resin are highly balanced.

[0062] The molecular weight distribution (weight-average molecular weight (Mw) / number-average molecular weight (Mn)) of the cyclic olefin polymer is preferably 1.2 or higher, more preferably 1.5 or higher, particularly preferably 1.8 or higher, preferably 3.5 or lower, more preferably 3.0 or lower, and particularly preferably 2.7 or lower. When the molecular weight distribution is above the lower limit of the above range, the productivity of the polymer can be increased and manufacturing costs can be suppressed. Furthermore, when it is below the upper limit, the amount of low molecular weight components is reduced, which can suppress relaxation during high-temperature exposure and improve the stability of the film.

[0063] The weight-average molecular weight and number-average molecular weight are the weight-average molecular weights in terms of polyisoprene or polystyrene, measured by gel permeation chromatography using cyclohexane as the solvent. However, if the sample does not dissolve in cyclohexane in the aforementioned gel permeation chromatography, toluene may be used as the solvent.

[0064] The glass transition temperature of the cyclic olefin polymer is preferably 130°C or higher, more preferably 135°C or higher, preferably 150°C or lower, and more preferably 145°C or lower. When the glass transition temperature is above the lower limit of the above range, the durability of the film at high temperatures can be improved. Furthermore, when the glass transition temperature is below the upper limit of the above range, stretching can be easily performed.

[0065] As the aforementioned cyclic olefin polymer, for example, one described in International Publication No. 2017 / 145718 may be used.

[0066] The proportion of the cyclic olefin polymer in the cyclic olefin resin is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, and particularly preferably 90% to 100% by weight. When the proportion of the polymer is within the above range, sufficient heat resistance and transparency can be obtained.

[0067] The cyclic olefin resin may contain any components other than the cyclic olefin polymer, as long as they do not significantly impair the effects of the present invention. Examples of such components include colorants such as pigments and dyes; fluorescent whitening agents; dispersants; heat stabilizers; light stabilizers; ultraviolet absorbers; antistatic agents; antioxidants; lubricants; and the like. These may be used individually or in combination of two or more in any ratio.

[0068] (Meth)acrylic resin is a resin containing a (meth)acrylic polymer. A (meth)acrylic polymer refers to a polymer of acrylic acid or an acrylic acid derivative, and examples include polymers and copolymers of acrylic acid, acrylic acid esters, acrylamide, acrylonitrile, methacrylic acid, and methacrylic acid esters. Because (meth)acrylic polymers are strong and hard, films with high mechanical strength can be produced.

[0069] As the (meth)acrylic polymer, polymers containing structural units having a structure obtained by polymerizing (meth)acrylic acid esters are preferred. Examples of (meth)acrylic acid esters include alkyl esters of (meth)acrylic acid. Among these, compounds having a structure derived from (meth)acrylic acid and an alkanol or cycloalkanol having 1 to 15 carbon atoms are preferred. Furthermore, compounds having a structure derived from (meth)acrylic acid and an alkanol having 1 to 8 carbon atoms are even more preferred. By reducing the number of carbon atoms as described above, the elongation at the time of film breakage can be reduced.

[0070] Specific examples of acrylic acid esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-decyl acrylate, and n-dodecyl acrylate.

[0071] Specific examples of methacrylate esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, and n-dodecyl methacrylate.

[0072] Furthermore, the (meth)acrylic acid ester described above may have substituents such as hydroxyl groups or halogen atoms, as long as they do not significantly impair the effects of the present invention. Examples of (meth)acrylic acid esters having such substituents include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, and glycidyl methacrylate. These may be used individually or in combination of two or more in any ratio.

[0073] Furthermore, the (meth)acrylic polymer may be a polymer of acrylic acid or an acrylic acid derivative alone, or it may be a copolymer of acrylic acid or an acrylic acid derivative with any monomer copolymerizable thereto. Examples of arbitrary monomers include α,β-ethylenically unsaturated carboxylic acid ester monomers other than the (meth)acrylic acid esters mentioned above, as well as α,β-ethylenically unsaturated carboxylic acid monomers, alkenyl aromatic monomers, conjugated diene monomers, unconjugated diene monomers, carboxylic acid unsaturated alcohol esters, and olefin monomers. These may be used individually or in combination of two or more in any ratio.

[0074] When the (meth)acrylic polymer contains any monomer, the amount of structural units having a structure obtained by polymerizing the arbitrary monomer in the (meth)acrylic polymer is preferably 50% by weight or less, more preferably 15% by weight or less, and particularly preferably 10% by weight or less.

[0075] Of these (meth)acrylic polymers, polymethacrylate is preferred, and polymethyl methacrylate is more preferred.

[0076] As the (meth)acrylic polymer mentioned above, for example, one described in International Publication No. 2017 / 145718 may be used.

[0077] The proportion of (meth)acrylic polymer in the (meth)acrylic resin is preferably 50% to 100% by weight, more preferably 70% to 100% by weight, and particularly preferably 90% to 100% by weight. When the proportion of polymer is within the above range, sufficient mechanical strength can be obtained.

[0078] The (meth)acrylic resin may contain any components other than the (meth)acrylic polymer, as long as they do not significantly impair the effects of the present invention. Examples of such components are similar to those that may be contained in the cyclic olefin resin. Furthermore, any component may be used individually or in combination of two or more components in any ratio.

[0079] The aforementioned base material layer can be manufactured by molding a resin using an appropriate film molding method. Examples of film molding methods include casting, extrusion, and inflation molding. Among these, the melt extrusion method, which does not use solvents, is preferred because it can efficiently reduce the amount of residual volatile components, and is preferable from the viewpoint of the global environment, the working environment, and manufacturing efficiency. As for the melt extrusion method, the inflation method using a die may be used, but the T-die method is preferred in terms of productivity and thickness accuracy.

[0080] When using a multilayer film comprising two or more layers as a long film, it is preferable that the multilayer film comprises a base layer and a functional layer. The functional layer may be provided on one side of the base layer or on both sides. In particular, it is preferable that the functional layer is provided on the knurled side of the base layer, and it is even more preferable that the knurled portion is provided on the surface of the functional layer. Examples of such functional layers include antistatic layers, hard coat layers, anti-adhesion layers, and easy-adhesion layers.

[0081] An antistatic layer refers to a layer having a low surface resistance value. Preferably, the surface resistance value of the antistatic layer is 1.0 × 10⁻⁶. 6 Ω / □ or greater, more preferably 1.0 × 10 7 Ω / □ or greater, particularly preferably 1.0 × 10 8 The ratio is Ω / □ or greater, preferably 1.0 × 10⁻⁶. 10 Ω / □ or less, more preferably 5.0 × 10 9 Ω / □ or less, particularly preferably 1.0 × 10 9 The resistance is less than or equal to Ω / □. The surface resistance can be measured using a digital ultra-insulating / micro-current meter (HIOKI DSM-8104) in accordance with JIS K6911. Such an antistatic layer can be formed, for example, from a resin containing conductive particles such as metal oxide particles and a polymer.

[0082] A hard coat layer refers to a layer having high hardness. The specific hardness of the hard coat layer, expressed in terms of JIS pencil hardness, is preferably B or higher, more preferably HB or higher, and particularly preferably H or higher. Here, JIS pencil hardness is defined in accordance with JIS K5600-5-4, where pencils of various hardness levels are tilted at a 45° angle, a 500g load is applied from above, and the surface of the layer is scratched; the hardness of the pencil at which scratching begins is the hardness of the pencil. Such a hard coat layer can be formed, for example, from resin.

[0083] An anti-adhesion layer is a layer having a rough surface that can suppress adhesion between films when layered with other films. Such an anti-adhesion layer can be formed, for example, from a resin containing polymers and particles.

[0084] An easy-to-adhere layer is a layer that exhibits high adhesion when its surface is bonded to another component. Such an easy-to-adhere layer can be formed, for example, from a resin containing a polymer.

[0085] Among the functional layers mentioned above, the easy-adhesion layer is preferred. The easy-adhesion layer is preferably a layer containing a water-based resin. A water-based resin is a resin that can be prepared as a solution or dispersion using water as a medium. By applying an aqueous solution or aqueous dispersion containing a water-based resin to the surface of the substrate layer and drying it, a layer of water-based resin can be formed on the surface of the substrate layer. Examples of water-based resins include urethane resins, polyester resins, and emulsions of each resin, with water-based urethane resin being preferred.

[0086] For example, the functional layer described in International Publication No. 2017 / 145718 may be used.

[0087] [4. Method for manufacturing long films] The long film described above can be manufactured, for example, by a manufacturing method that includes a step of irradiating the film with laser light before the uneven surface is formed. Hereinafter, the film before the uneven surface is formed may be referred to as the "pre-processed film" as appropriate.

[0088] Laser irradiation is typically performed while continuously transporting the pre-treatment film in the longitudinal direction of the film. When laser light is irradiated onto at least one side of the pre-treatment film, localized thermal melting or ablation occurs at the irradiated location. As a result, convex and concave deformations, which form uneven surfaces, can be created in the pre-treatment film at the irradiated location.

[0089] In this type of laser-based surface formation, no mechanical force is required, making it less likely for residual stress to remain in the uneven areas. Therefore, it is possible to suppress the occurrence of breakage originating from the uneven areas in long films. Furthermore, even when using thin pre-treated films, it is easier to suppress film breakage during the formation of uneven areas. In addition, it is possible to suppress the generation of foreign matter due to the formation of uneven areas.

[0090] During the laser irradiation process, the irradiation point where the laser beam strikes the film before processing is moved to draw the planar shape of the uneven surface to be formed. As a result, uneven surfaces are formed in the path left by the movement of the laser irradiation point, creating an uneven surface with the desired planar shape.

[0091] When forming multiple uneven areas on a film before processing, it is preferable to continuously draw the planar shape of each uneven area without interrupting the line (single-stroke drawing). This allows the laser light to be continuously irradiated for the duration of forming each uneven area. Therefore, variations in the shape of the multiple uneven areas can be suppressed, enabling the stable formation of uneven areas.

[0092] When drawing the planar shape of a single uneven surface, it is preferable to start the irradiation of the laser light near the center of the knurled portion 101 in the width direction (preferably the center of the knurled portion 101 in the width direction). Typically, the height of the uneven surface is highest at the start of the irradiation of the laser light. Therefore, the uneven surface is highest near the center of the knurled portion 101 in the width direction, and the movement of the overlapping portion of the film roll 1300 is effectively restricted, thereby effectively suppressing the occurrence of defects in the film roll 1300.

[0093] The movement speed of the laser beam irradiation point can be arbitrarily set within a range that allows for the formation of desired irregularities. Specifically, the movement speed is preferably 500 mm / s or more, more preferably 1000 mm / s or more, particularly preferably 1500 mm / s or more, preferably 10000 mm / s or less, more preferably 9000 mm / s or less, and particularly preferably 8000 mm / s or less. When the movement speed of the laser beam irradiation point is above the lower limit of the above range, the time required for drawing can be shortened, and irregularities can be formed at high speed. Furthermore, when the movement speed of the laser beam irradiation point is below the upper limit of the above range, the occurrence of overshoot due to the inertia of movable parts (mirrors, etc.) included in the laser optical system can be suppressed, thereby suppressing deformation from the desired shape and rounding of corners.

[0094] Examples of laser devices used for irradiating laser light include ArF excimer lasers, KrF excimer lasers, XeCl excimer lasers, YAG lasers (especially third or fourth harmonic), YLF or YVO4 solid-state lasers (especially third or fourth harmonic), Ti:S lasers, semiconductor lasers, fiber lasers, and carbon dioxide lasers. Among these laser devices, carbon dioxide lasers are preferred because they are relatively inexpensive and can efficiently provide output suitable for film processing.

[0095] The laser output is preferably 1W or more, more preferably 5W or more, particularly preferably 15W or more, preferably 200W or less, more preferably 190W or less, even more preferably 180W or less, and particularly preferably 170W or less. By setting the laser output to be above the lower limit of the above range, insufficient laser irradiation can be suppressed, and uneven surfaces can be stably formed. Furthermore, by setting the laser output to be below the upper limit of the above range, the occurrence of through holes in the film can be suppressed.

[0096] [5. Embodiment of a film roll manufacturing method] The winding device 1000 and the long film 1 according to this embodiment have the structure described above. When manufacturing a film roll 1300 by winding the long film 1 using such a winding device 1000, the manufacturing method for the film roll 1300 includes the steps of winding the long film 1 onto the touch roll 1130 and winding the long film 1 wound onto the touch roll 1130 onto the winding core 1110. This manufacturing method will be described below.

[0097] In the manufacturing method of the film roll 1300 according to this embodiment, as shown in Figure 1, the long film 1 is continuously conveyed in the longitudinal direction of the long film 1 and supplied to the touch roll 1130. At this time, the conveying speed of the long film 1 is usually equal to the winding speed when the long film 1 is wound on the winding core 1110. Therefore, it is preferable to set the conveying speed of the long film 1 so that a desired winding speed can be achieved. The specific range of the winding speed of the long film 1 is preferably 10 m / min or more, more preferably 15 m / min or more, particularly preferably 20 m / min or more, preferably 150 m / min or less, more preferably 140 m / min or less, and particularly preferably 130 m / min or less. By keeping the winding speed of the long film 1 within the above range, the occurrence of defects in the film roll 1300 after manufacturing can be effectively suppressed.

[0098] The long film 1 supplied to the touch roll 1130 is wound onto the touch roll 1130. At this time, since the touch roll 1130 is provided to be freely rotatable, it rotates in the circumferential direction due to the frictional force provided by the wound long film 1. Then, the long film 1 is guided to the winding core 1110 by the touch roll 1130 which is rotating in this manner. If necessary, the touch roll 1130 may be provided with a driving force to rotate it. For example, if the frictional force between the touch roll 1130 and the long film 1 is small, or if the touch roll 1130 is heavy, a rotational driving force may be provided to the touch roll 1130 to the extent that it can reduce mechanical loss.

[0099] The winding core 1110 rotates circumferentially due to the driving force supplied by the winding core motor 1120. Therefore, the long film 1, guided to the winding core 1110 while wound onto the touch roll 1130, is wound onto the winding core 1110. The long film 1 wound onto the winding core 1110 then forms the film roll 1300. At this time, the touch roll 1130 is positioned by the arm 1140 so that it contacts the long film 1 that has already been wound onto the winding core 1110 and become part of the film roll 1300 in the process of being manufactured. Hereafter, the position where the touch roll 1130 contacts the long film 1 that has already been wound onto the winding core 1110 and become part of the film roll 1300 in the process of being manufactured may be referred to as the "winding position." As shown in Figure 1, this winding position P W This is the position where the long film 1 wound around the touch roll 1130 begins to come into contact with the winding core 1110 or the film roll 1300 in the process of being manufactured.

[0100] When winding the long film 1 onto the winding core 1110, the touch roll 1130, due to a biasing force provided by an air cylinder (not shown), presses the film roll 1300 in the manufacturing process radially toward the winding core 1110 with a predetermined load. As a result, the long film 1 wound onto the winding core 1110 (i.e., the long film contained in the film roll 1300 in the manufacturing process) is pressed toward the center of the winding core 1110 with a predetermined load. Therefore, when winding the long film 1, the entrapment of air between the circumferential surface 1301 of the film roll 1300 in the manufacturing process and the long film 1 is suppressed.

[0101] Because air entrapment between the peripheral surface 1301 of the film roll 1300 during manufacturing and the long film 1 is suppressed, the winding at both axial ends of the film roll 1300 becomes sufficiently tight. At the same time, the movement of the film in the axial center of the film roll 1300, where no uneven portion 10 is formed, is restricted, effectively suppressing the occurrence of uneven defects in the film near the knurled portion 101.

[0102] The magnitude of the load applied by the touch roll 1130 to the film roll 1300 during manufacturing is preferably 5 N / m or more, more preferably 10 N / m or more, particularly preferably 15 N / m or more, preferably 150 N / m or less, more preferably 120 N / m or less, and particularly preferably 100 N / m or less. Here, the unit of load "N / m" represents the magnitude of the force applied per meter of width of the long film. By keeping the magnitude of the load within the above range, the occurrence of defects in the film roll 1300 after manufacturing can be effectively suppressed.

[0103] The magnitude of the load applied by the touch roll 1130 to the film roll 1300 during manufacturing may be arbitrarily varied within the above range according to the winding diameter of the film roll 300 during manufacturing. In this case, for example, the magnitude of the load may be changed to gradually decrease, to gradually increase, or a combination of these may be used.

[0104] When winding the long film 1 onto the winding core 1110, it is preferable to keep the winding tension of the long film 1 within a predetermined range. Specifically, the range of winding tension is preferably 80 N / m or more, more preferably 85 N / m or more, particularly preferably 90 N / m or more, preferably 150 N / m or less, more preferably 145 N / m or less, and particularly preferably 140 N / m or less. The unit "N / m" for the winding tension represents the magnitude of the force applied per meter of width of the long film. By keeping the winding tension of the long film 1 within the above range, the occurrence of defects in the film roll 1300 after manufacturing can be effectively suppressed.

[0105] The winding tension of the long film 1 may be arbitrarily changed within the above range according to the winding diameter of the film roll 1300 during manufacturing. In this case, for example, the winding tension may be changed to gradually decrease, to gradually increase, or a combination of these may be used. In particular, it is preferable to adjust the winding tension so that it gradually decreases over time.

[0106] [6. Film Roll] The film roll manufacturing method of this embodiment yields a film roll in which the occurrence of defects in the film is suppressed. Figure 6 is a schematic partial cross-sectional view showing a film roll that can be obtained by a film roll manufacturing method according to one embodiment of the present invention. Figure 6 shows a part of the cross-section when the film roll is cut, with respect to a plane including the axis of the film roll. As shown in Figure 6, the film roll 1300 has raised portions 1310 at both axial ends, the raised portions having an arched cross-sectional contour. The raised portions 1310 correspond to the overlapping portions of the knurled sections formed at both ends of the long film. In this embodiment, the film roll 1300 has 40 corners per unit area of ​​the knurled section per cm. 2The above is more than sufficient. As mentioned above, the height of the unevenness at the corners is usually higher than the height of the unevenness at the straight sections. Because these high corners are distributed at a high density in the knurled section, the raised portions 1310 at both ends of the film roll 1300 have slopes 1311 with a small gradient compared to the case where the corners are distributed at a low density in the knurled section. In a film roll 1300 having such raised portions 1310, the corners present in the lower knurled section evenly support the wound long film, restricting the movement of the wound long film in the axial direction of the long film, and effectively suppressing the occurrence of defects. The slope θ of the inclination θ of the slope 1311 of the raised portion 1310, which is the part where the knurled sections overlap. 1311 For example, it is preferably less than 0.050° and preferably 0.010° ​​or more.

[0107] Figure 7 shows that the number of corners per unit area of ​​the knurled section is 40 corners / cm². 2 This is a schematic partial cross-sectional view of a film roll according to a comparative example, manufactured from a small length of film. Figure 7 shows a portion of the cross-section when the film roll is cut along a plane containing the axis of the film roll. As shown in Figure 7, the film roll 5000 has raised portions 5010 at both ends in the axial direction. The raised portion 5010 has a sloped surface 5011 whose slope is greater than that of the raised portion 1310. The slope θ of the sloped surface 5011 of the raised portion 5010 5011 For example, this is 0.050° or greater.

[0108] [7. Uses of film rolls] The film rolls produced by the above manufacturing method can be applied to films for any application, such as optical films, moisture-proof films, packaging films, conductive films, insulating films, antistatic films, barrier films, and films for wiring boards. In particular, it is preferable to use them for optical films from the viewpoint of effectively utilizing the advantage of being able to suppress defects. Examples of optical films include phase difference films, protective films for polarizing plates, polarizing films, brightness-enhancing films, light-diffusing films, light-gathering films, and reflective films. These optical films can be manufactured, for example, by a manufacturing method that includes a step of manufacturing a film roll using the manufacturing method described above. [Examples]

[0109] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples shown below, and can be modified and implemented as appropriate without departing from the scope of the claims and equivalents of the present invention.

[0110] In the following explanation, "%" and "parts" used to express quantities refer to weight unless otherwise specified. Furthermore, the operations described below were performed under normal temperature (20°C ± 15°C) and atmospheric pressure (1 atm) conditions unless otherwise specified.

[0111] [Evaluation Method] (Method for measuring the height of uneven surfaces) The height of the knurled areas on the long film was measured using a three-dimensional surface profiler (Zygo's "NewView5000"). The average height of all corners with angles between 80° and 100° contained within any given area was calculated and used as the average height of the area.

[0112] (Method for measuring the radius of curvature of corners) The radius of curvature at each corner of the knurled section of the long film was measured using a three-dimensional surface profiler (Zygo's "NewView5000").

[0113] (Method for evaluating defects) While unwinding the film from the film roll, the entire width of the film was photographed with a camera to detect defects. Next, the images of the detected defects were re-examined to determine the type of defect. Defects located near the knurled area (approximately 50 mm inward from the edge of the film) were classified as "irregular defects near the knurled area." Linear defects present in the central part of the film, excluding the areas near the knurled spots, were classified as "scratches." Point-like defects located in the central part of the film, excluding the areas near the knurling, were classified as "bumps." Each of these defects was evaluated according to the following criteria. A: No defects B: There is a defect, but it is only slightly visible. C: There is a clearly visible defect.

[0114] [Examples 1 and 2] (Manufacturing of the base layer) Pellets of cyclic olefin resin (ZEONOR, manufactured by Zeon Corporation; glass transition temperature 135°C) were dried at 70°C for 2 hours using a hot air dryer with circulating air. The dried pellets were supplied to a T-die type film melt extrusion molding machine equipped with a resin melt kneader with a 65 mmφ screw, and extrusion molding was performed under molding conditions of a molten resin temperature of 270°C and a T-die width of 1700 mm to produce a long substrate layer (thickness 50 μm, width 1500 mm, length 4000 m).

[0115] (Manufacturing of pre-treatment film (formation of easy-adhesion layer)) A liquid aqueous dispersion of a water-based urethane resin with a solid content of 2% was obtained by blending 100 parts of a polyether-based polyurethane aqueous dispersion (Superflex 870, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) by the amount of polyurethane, 15 parts of an epoxy compound (Denacol EX313, manufactured by Nagase ChemteX Corporation) as a crosslinking agent, 8 parts of an aqueous dispersion of silica particles (Snowtex MP1040, manufactured by Nissan Chemical Corporation; average particle size 120 nm) by the amount of silica particles and 8 parts of an aqueous dispersion of silica particles (Snowtex XL, manufactured by Nissan Chemical Corporation; average particle size 50 nm) by the amount of silica particles as lubricants, an acetylene-based surfactant (Surfinol 440, manufactured by Air Products and Chemicals Inc.) at 0.5% by weight relative to the total amount of solids as a wetting agent, and water.

[0116] The aqueous dispersion of the water-based urethane resin was applied to one side of the aforementioned substrate layer using a reverse roll method so that the thickness after drying was 45 nm, and then dried at 90°C. This formed an easy-adhesion layer on one side of the substrate layer, obtaining a pre-treatment film with a multilayer structure comprising the substrate layer and the easy-adhesion layer.

[0117] (Formation of knurled areas) The aforementioned untreated film was transported in the longitudinal direction at a speed of 30 m / min. Then, laser light was irradiated onto the easily adhesive layer side of both the left and right ends in the width direction of the transported untreated film to form multiple uneven areas, thereby obtaining a long film having knurled areas on both the left and right ends in the width direction. A CO2 laser irradiation device (Coherent Corporation "J3 series", laser wavelength 9.4 μm) was used as the laser irradiation device. The laser irradiation output was set to 120 W. Furthermore, the laser irradiation was performed while moving the laser irradiation point with a galvanometer scanner at a moving speed of 7000 mm / s to draw the desired planar shape of the uneven areas.

[0118] As a result of the irradiation with the aforementioned laser light, multiple uneven surfaces 10 with a width W of 0.2 mm and a planar shape as shown in Figure 3 were formed.

[0119] The angles of all corners 131 included in the uneven portion 10 were all 90°. Furthermore, the radius of curvature of all corners 131 included in the uneven portion 10 was all 0.2 mm.

[0120] Length L of the uneven portion 10 in the longitudinal direction MD of the film MD The film width is 1.9 mm, and the length of the uneven portion 10 in the film width direction TD is L. TD The width was 9.4 mm. Furthermore, the pitch of the uneven surface 10 in the longitudinal direction MD of the film was 3.0 mm. The width W1 of the knurled portion formed on the film was 9.4 mm. Furthermore, when the average height of the uneven surface 10 was measured, it was found to be 3 μm. Each of the 10 uneven sections has 24 corners with a 90° angle, and the knurled section is 1 cm 2 The number of corners with an angle of 90° was 85.

[0121] (Winding up long rolls of film) The long film was supplied to the winding device 1000 (see Figure 1) having the structure described in the above-described embodiment. Then, under the winding conditions shown in Table 1, a film roll 1300 was manufactured by winding the long film 1 onto the touch roll 1130 and winding the long film 1 wound onto the touch roll 1130 onto the winding core 1110. The manufactured film roll was then evaluated using the method described above.

[0122] [Comparative Example 1] Figure 8 is a schematic plan view showing the planar shape of the uneven portion 500 formed in Comparative Example 1. The planar shape of the uneven portion 500 was changed to the same shape as in Example 1 of International Publication No. 2017 / 145718, as shown in Figure 8. Except for the above, the long film and film roll were manufactured and evaluated using the same method as in Example 1.

[0123] In the uneven portion 500 formed in Comparative Example 1, the angle of corner 501 shown in Figure 8 is 90°, the angle of corner 502 is 135°, and the length L of the uneven portion 500 in the longitudinal direction MD of the film is... MD The film width is 1.2 mm, and the length of the uneven portion 500 in the film width direction TD is L. TD The film's thickness was 9.3 mm, and the pitch of the uneven surface 500 in the longitudinal direction MD was 4.2 mm. Furthermore, the average height of the uneven surface 500 was measured to be 3 μm. Each of the 500 uneven sections has 10 corners with a 90° angle, and the knurled section is 1 cm. 2 The number of corners with a 90° angle was 25.

[0124] [Comparative Example 2] A long film was manufactured using the same procedure as in Example 1, with multiple uneven surfaces 10 having the planar shape shown in Figure 3. However, the laser output was changed to 140W so that the average height of the uneven surfaces 10 was 7 μm. Next, instead of the winding device 1000, the winding device 2000 shown in Figure 9 was used to wind the long film 1 under the winding conditions shown in Table 1. Figure 9 is a schematic diagram showing an example of a winding device that implements the manufacturing method according to the comparative example. The winding device 2000 was equipped with a near roll 2130 instead of a touch roll 1130. The near roll 2130 did not push the film roll 2300 in the process of being manufactured toward the center of the winding core 1110, and the film roll 2300 in the process of being manufactured was not in contact with the near roll 2130. The obtained film rolls were evaluated in the same manner as in Example 1.

[0125] [Comparative Example 3] The planar shape of the uneven portion 10 was changed to the same shape as in Example 1 of International Publication No. 2017 / 145718, as shown in Figure 8. The laser beam output was changed to 140W so that the average height of the uneven portion 500 was 7 μm. Except for the matters mentioned above, the long film was manufactured using the same procedure as in Example 1. Next, instead of the winding device 1000, the winding device 2000 shown in Figure 9 was used to wind the long film 1 under the winding conditions shown in Table 1. The near roll 2130 did not push the film roll 2300 in the process of being manufactured toward the center of the winding core 1110, and the film roll 2300 in the process of being manufactured was not in contact with the near roll 2130. The obtained film rolls were evaluated in the same manner as in Example 1.

[0126] [Manufacturing conditions and results] The manufacturing conditions and results are shown in the table below. The abbreviations in the table below have the following meanings. "Density at 90° corners": Knurled section 1cm 2 Number of corners with an angle of 90° present in the area "Touch Roll Pressure": The magnitude of the force applied by the touch roll when pressing against the film roll during manufacturing. "Touch": Winding by winding device 1000 equipped with a touch roll. "Gap": Winding by winding device 2000 with near roll. "Unevenness Defect": Unevenness defect near the knurled area.

[0127] [Table 1]

[0128] The number of corners with an angle of 80° to 100° in the knurled area is 40 per cm. 2 Film rolls obtained by the manufacturing methods of Comparative Examples 1 and 3, which were less than [amount missing], showed defects such as unevenness near the knurled area, bumps, or scratches. The number of corners with an angle of 80° to 100° in the knurled area is 40 per cm. 2 In summary, in the manufacturing method described in Comparative Example 2, which uses a winding device equipped with a near-roll instead of a touch-roll, slight blemishes and scratches were observed. The film rolls obtained by the manufacturing methods described in Examples 1 and 2 showed no defects such as unevenness, bumps, or scratches near the knurled areas, and showed better results compared to Comparative Examples 1 to 3. [Explanation of Symbols]

[0129] 1: Long film 1U: Surface 10: Uneven part 11: Recess 12: Convex part 101: Naaru Department 111: Straight section 111a: line 112: Straight section 112a: line 131: Corner θ 131 :angle 500: Uneven part 501: Corner 502: Corner 1000: Winding device 1110: Core 1120: Core motor 1130: Touch Roll 1140: Arm 1300: Film Roll 1301: Peripheral surface 1310: Excitement Club 1311: Slope θ 1311 : slope 2000: Winding device 2130: Near Roll 2300: Film Roll 5000: Film Roll 5010: Excitement Club 5011: Slope θ 5011 : slope H: Height L1: Straight line L2: straight line R: radius of curvature W: Width W1: Width

Claims

1. A method for manufacturing a film roll, which involves winding a long film onto a core to produce a film roll, The manufacturing method comprises the steps of winding the long film onto a touch roll and winding the long film wound onto the touch roll onto a winding core. The touch roll pushes the film roll in the process of being manufactured toward the center of the winding core, The long film has a strip-shaped knurled portion with an uneven surface that extends along the entire length of the long film, and has these knurled portions at both ends in the width direction of the long film. The planar shape of the aforementioned uneven portion, when viewed from the thickness direction of the long film, includes a plurality of corners having angles of 80° to 100°, and the number of such corners in the knurled portion is 40 per cm. ２ The above describes the method for manufacturing a film roll.

2. The method for manufacturing a film roll according to claim 1, wherein the load applied by the touch roll to push the film roll in the process of being manufactured toward the center of the winding core is 5 N / m to 150 N / m.

3. The method for manufacturing a film roll according to claim 1 or 2, wherein the tension used to wind the long film wrapped around the touch roll onto the winding core is 80 N / m to 150 N / m.

4. A method for manufacturing a film roll according to any one of claims 1 to 3, wherein the average height of the uneven portion is 0.5 μm to 8 μm.

5. A method for manufacturing a film roll according to any one of claims 1 to 4, wherein the circumferential surface of the touch roll is formed of a material having a rubber hardness of 55 degrees or more.

6. A method for manufacturing a film roll according to any one of claims 1 to 5, wherein the uneven portion is formed by irradiation with laser light.

7. A method for manufacturing a film roll, comprising winding a long film onto a core, The manufacturing method comprises the steps of winding the long film onto a touch roll and winding the long film wound onto the touch roll onto a winding core. The touch roll pushes the film roll in the process of being manufactured toward the center of the winding core, The long film has a strip-shaped knurled portion having an uneven surface and extending in the longitudinal direction of the long film, at both ends in the width direction of the long film. The planar shape of the aforementioned uneven portion, when viewed from the thickness direction of the long film, includes a plurality of corners having angles of 80° to 100°, and the number of such corners in the knurled portion is 40 or more per cm². The film roll has a raised portion where the knurled portion overlaps, A method for manufacturing a film roll, wherein the slope of the inclined surface of the raised portion is 0.010° ​​or more and less than 0.050°.

8. The method for manufacturing a film roll according to claim 7, wherein the load applied by the touch roll to push the film roll in the process toward the center of the winding core is 5 N / m to 150 N / m.

9. The method for manufacturing a film roll according to claim 7 or 8, wherein the tension used to wind the long film wrapped around the touch roll onto the winding core is 80 N / m to 150 N / m.

10. A method for manufacturing a film roll according to any one of claims 7 to 9, wherein the average height of the uneven portion is 0.5 μm to 8 μm.

11. A method for manufacturing a film roll according to any one of claims 7 to 10, wherein the circumferential surface of the touch roll is formed of a material having a rubber hardness of 55 degrees or more.

12. A method for manufacturing a film roll according to any one of claims 7 to 11, wherein the uneven portion is formed by irradiation with laser light.

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