Film roll and method for manufacturing the same

Abstract

To provide a film roll in which the occurrence of winding slippage at the end of the film roll and occurrence of a scratch at the winding core side are inhibited, and a manufacturing method thereof.SOLUTION: A film roll has a winding core and a long film wound thereon. The film roll has two knurl parts disposed at both ends in the width direction and a flat part arranged between the two knurl parts. The heights ΔD1 and ΔD2 of the knurl level differences obtained from a shape profile of the film roll surface measured by a laser displacement gage are 0.1 mm or more to 1.0 mm or less, in which a wound length of the long film is L / 25 (m) or more when a final wound length of the long film is represented as L (m).SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a film roll in which slippage at the end of the film roll and scratches on the core side are suppressed.

Background Art

[0002] Currently, films and sheets are used in various applications such as building materials, daily necessities, flat panel displays, solar power generation, lighting, automobiles, and household appliances. Many of the films and sheets are aimed at higher functionality, larger size, thinner thickness, lower price, and power saving. However, for further price reduction of films and sheets, high speed, thin film, long length, and wide width in molding are being promoted, and it has become important to maintain the quality of film rolls wound around a core for a long period of time.

[0003] As a technique for maintaining the quality of a film roll for a long period of time, for example, a technique for forming a narl part on a film roll by forming a narl structure such as a plurality of convex parts or an uneven structure at both ends in the width direction of a long film and winding it is known. As a method for imparting a narl structure to a film, various methods are known, such as a method of bringing a mold having a narl structure into contact with the film (Patent Documents 1 and 2) and a method of irradiating the film with laser light. Furthermore, as a technique for obtaining a film roll with good quality, measuring the winding diameter distribution of the film and winding the film roll (Patent Document 3), defining the air thickness between the winding rolls (Patent Document 4), changing the pressing force and tension when winding a long film according to the change in the winding diameter (Patent Document 5), and forming a narl structure with different heights on a long film to manufacture a film roll (Patent Document 6) have been reported.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] By the way, during the transportation of the film roll, "misalignment" and "scratches" may occur due to the acceleration applied in the roll width direction. "Misalignment" is a defect in the appearance of the film roll, such as when the frictional force of the film roll cannot withstand the force applied in the width direction and the roll end face is displaced. In addition, "scratches" are defects that occur on the surface of the long film, such as when the film roll sways in the roll width direction due to periodic vibrations applied in the roll width direction, and minute scratches occur on the core side where the radial stress of the film is high.

[0006] The present invention has been made in view of the above, and an object thereof is to provide a film roll in which misalignment at the end of the film roll and the occurrence of scratches on the core side are suppressed, and a method for manufacturing the same. [Means for Solving the Problems]

[0007] In order to solve the above problems, the present inventors have intensively studied and obtained the following findings. In a long film, the knurled area including a plurality of convex portions has a greater film thickness than the flat area not including the convex portions. When such a long film is wound up to form a film roll, the knurled portion including the laminated portion of the knurled area usually has a larger winding diameter than the flat portion including the laminated portion of the flat area, and the shape of the film roll surface has a stepped shape in which the knurled portion bulges compared to the flat portion. The inventors have found that the height of the stepped shape during winding of the film roll affects the occurrence of winding deviation and scratches, and have completed the present invention by finding that both the occurrence of winding deviation and scratches can be suppressed by setting the height of the stepped shape during winding within a specific range. That is, the present invention provides the following.

[0008] [1] A film roll having a core and a long film wound around the core, wherein the long film has two knurled areas provided at both ends in the width direction and including a plurality of convex portions, and a flat area provided between the two knurled areas, and the film roll has two knurled portions provided at both ends in the width direction and including a laminated portion of the knurled area of the long film and a laminated portion of the flat area adjacent to the knurled area, and a flat portion provided between the two knurled portions and including a laminated portion of the flat area of the long film, and when the final winding length of the long film is L (m), at a winding length of L / 25 (m) or more, based on the shape profile of the film roll surface measured by a laser displacement meter, the height ΔD1 of the first knurled step and the height ΔD2 of the second knurled step defined by the following formula (1) and the following formula (2) are 0.1 mm or more and 1.0 mm or less. ΔD1=(D N1(MAX) -D F1(AVE) ) / 2 (1) ΔD2=(D N2(MAX) -D F2(AVE) ) / 2 (2) (In the formula (1), D N1(MAX) is the maximum value of the diameter of one of the two knurled portions of the film roll, and D F1(AVE)is the average value of the diameters of the flat portions on the side of the one flange portion of the film roll. In the formula (2), D N2(MAX) is the maximum value of the diameters of the other flange portion among the two flange portions of the film roll, and D F2(AVE) is the average value of the diameters of the flat portions on the side of the other flange portion of the film roll.) [2] The film roll according to [1], wherein the shape profile of the flange portion on the surface of the film roll is a convex shape or a flat shape. [3] The film roll according to [1] or [2], wherein the resin material of the long film is a resin containing a cycloolefin polymer. [4] The film roll according to any one of [1] to [3], wherein the height of the convex portion included in the flange region of the long film is 4 μm or more and 15 μm or less. [5] The film roll according to any one of [1] to [4], wherein the ratio of the width of the flange region to the total width of the long film is 0.3% or more and 5.0% or less. [6] The film roll according to any one of [1] to [5], wherein the average thickness of the long film in the flat region is 10 μm or more and 100 μm or less. [7] The film roll according to any one of [1] to [6], wherein the length of the long film is 2000 m or more and 8000 m or less. [8] A method for manufacturing a film roll according to any one of [1] to [7], including a step of measuring the shape profile of the surface of the film roll in a range including the flange portion and the flat portion on the side of the flange portion from the edge of the film roll using a laser displacement meter, and winding the long film so that ΔD1 and ΔD2 at a winding length of L / 25 (m) or more when the final winding length of the long film is L (m) are 0.1 mm or more and 1.0 mm or less. [9] The method for manufacturing a film roll according to [8], wherein the long film is wound at a winding speed of 10 m / min or more and 100 m / min or less.

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a film roll in which displacement at the end of the film roll and generation of scratches on the core side are suppressed, and a method for manufacturing the same.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in detail with reference to embodiments and exemplifications. However, the present invention is not limited to the embodiments and exemplifications shown below, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

[0012] In the following description, the "long" film refers to a film having a length of 5 times or more the width, preferably 10 times or more the length, and specifically refers to a film having a length such that it can be wound up and stored or transported in a roll shape. The upper limit of the length of the film is not particularly limited, and can be, for example, 100,000 times or less the width.

[0013] In the following description, the diagonal direction of the long film refers to the in-plane direction of the film, which is not parallel or perpendicular to the longitudinal direction of the film, unless otherwise specified.

[0014] In the following description, the term "(meth)acrylic" includes "acrylic", "methacrylic" and combinations thereof.

[0015] In the following description, unless otherwise specified, the directions of the elements "parallel", "perpendicular" and "orthogonal" may include errors within a range that does not impair the effects of the present invention, for example, within a range of ±3°, ±2° or ±1°.

[0016] In the following description, the diameter D of the film roll is the distance between two intersections of a straight line passing through the rotation axis of the film roll and the circumference of the film roll in the cross-sectional circumferential shape in the axial direction of the film roll, and the radius R of the film roll is the distance between the rotation axis of the film roll and the circumference of the film roll in the cross-sectional circumferential shape. Also, the diameter D and radius R of the film roll refer to the diameter and radius of the entire film roll, including the diameter and radius of the core.

[0017] [1. Film roll] The film roll in the present invention has a core and a long film.

[0018] [1.1. Long film] FIG. 1 is a schematic view showing a long film pulled out from a film roll according to an embodiment of the present invention as viewed from the thickness direction of the long film. The long film 10 is provided with a nailing area 12a and a nailing area 12b at the end 11a in the width direction and the end 11b in the width direction, and a flat area 13 is provided between the nailing area 12a and the nailing area 12b. The nailing areas 12a, 12b and the flat area 13 are each a strip-shaped area extending in the length direction of the long film 10. A plurality of convex portions 14 are provided in the nailing areas 12a and 12b. No plurality of convex portions 14 are provided in the flat area 13, and the flat area 13 is an area that is substantially flat, preferably flat.

[0019] (1.1.1. Nailing area and flat area) The nailing areas of the long film are provided at both ends in the width direction and are usually provided within a range of a certain distance from the edge of the long film. As shown in FIG. 1, the nailing areas 12a and 12b may be provided without being separated from the edges e1 and e2 of the long film, and although not shown, they may be provided at positions separated from the edge of the long film. When the nailing area is provided at a position separated from the edge of the long film, the distance from the edge to the nailing is, for example, 10 mm or less, preferably 5 mm or less, more preferably 3 mm or less.

[0020] The nailing area is usually a strip-shaped area extending parallel to the length direction of the long film. The width (width of the strip) of the nailing area can be any value. The width of the nailing area may be, for example, 3 mm or more, more preferably 5 mm or more, particularly preferably 7 mm or more, preferably 20 mm or less, more preferably 18 mm or less, particularly preferably 16 mm or less. Also, for example, the widths of the nailing areas 12a, 12b may each be 0.3% or more, 0.5% or more, 5.0% or less, or 3% or less with respect to the total width of the long film.

[0021] FIG. 2 is a partial cross-sectional view schematically showing an example of the nailing area of the long film. As shown in FIG. 2, the knurl region 12a of the long film 10 includes a plurality of convex portions 14. The plurality of convex portions 14 protrude from one surface 10U of the long film 10. On the other hand, the other surface 10D of the long film 10 is substantially flat, preferably flat, and no convex portion 14 is formed thereon.

[0022] The height of the convex portion can be any value. For example, it is preferably 4 μm or more, more preferably 7 μm or more, preferably 15 μm or less, and more preferably 12 μm or less. As shown in FIG. 2, the height of the convex portion refers to the height 14h up to the top of the convex portion 14 with respect to the surface 10U of the long film 10 having no convex portion in the knurl region.

[0023] The shape of the convex portion can be any shape. Examples of the shape of the convex portion include a columnar shape, a prismatic shape, a conical shape, a pyramidal shape, a frustum of a cone shape, and a shape obtained by cutting out a part of a sphere. Also, the diameter, pitch, and density of the convex portions can be any values. The diameter of the convex portion can be, for example, 100 μm or more and 4000 μm or less. The pitch of the convex portions can be, for example, 100 μm or more and 4000 μm or less. The density of the convex portions can be, for example, 5 pieces / cm 2 or more and 100 pieces / cm 2 or less. Note that the diameter of the convex portion is the diameter r of the bottom surface shape of the convex portion 14 in FIG. 2, and when the shape of the convex portion is a prismatic shape, a pyramidal shape, or a frustum of a pyramid shape, it is the diameter of the inscribed circle of the bottom surface shape of the convex portion. Also, the pitch of the convex portions is the distance q between the centers of adjacent convex portions 14 in FIG. 2.

[0024] The plurality of convex portions constituting the knurled region may be provided such that the height, shape, diameter, pitch, and density of each convex portion are the same, or at least one of them may be provided to be different. For example, when the shape of the knurled portion on the surface of the film roll is convex, it can be adjusted by making the height of the convex portion located on the end side of the knurled region lower than the height of the convex portion located on the central side of the knurled region. Further, for example, when the knurled shape on the surface of the film roll is concave, it can be adjusted by making the height of the convex portion located on the end side of the knurled region higher than the height of the convex portion located on the central side.

[0025] There is no limitation on the method of forming the convex portion. For example, a method of forming the convex portion by irradiating laser light can be mentioned.

[0026] The flat region of the long film is provided between the above-mentioned two knurled regions and is generally a region that is substantially flat, preferably flat, and in which no plurality of convex portions are provided. The average thickness of the flat region is, for example, preferably 10 μm or more, more preferably 30 μm or more, preferably 100 μm or less, and more preferably 80 μm or less. Here, the average thickness of the flat region can be, for example, the arithmetic mean of the thicknesses measured at a plurality of positions arranged in the width direction of the flat region. The interval in the width direction of the positions where the thickness is measured can be, for example, 5 mm.

[0027] (1.1.2. Material of the long film) The material for forming the long film is preferably a resin. The resin usually contains a polymer and, if necessary, components other than the polymer. Examples of the polymer that can be contained in the resin for forming the long film include cellulose-based polymers such as triacetyl cellulose, polyester, polyethersulfone, polycarbonate, polyamide, polyimide, polyolefin, cycloolefin polymer, and (meth)acrylic-based polymer. Among them, from the viewpoints of transparency, low moisture absorption, dimensional stability, light weight, etc., a cycloolefin polymer is preferable.

[0028] The resin for forming the long film may contain the polymer alone or in any combination of two or more in any ratio.

[0029] A film formed from a resin containing a cycloolefin polymer (cycloolefin polymer) tends to be more prone to scratches compared to resin films such as triacetyl cellulose films and polyethylene terephthalate films. However, the film roll according to the present embodiment can effectively reduce scratches even when it is a roll wound with such a long resin film that is prone to scratches.

[0030] A cycloolefin polymer is a polymer having a structure obtained by polymerizing a cycloolefin monomer. Further, a cycloolefin monomer is a compound having a ring structure formed of carbon atoms and having a polymerizable carbon-carbon double bond in the ring structure. Examples of the polymerizable carbon-carbon double bond include carbon-carbon double bonds capable of polymerization such as ring-opening polymerization. Examples of the ring structure of the cycloolefin monomer include monocyclic, polycyclic, condensed polycyclic, bridged ring, and polycyclic combinations thereof. Among them, polycyclic cycloolefin monomers are preferred.

[0031] Among the above cycloolefin polymers, preferred ones include norbornene-based polymers, monocyclic cyclic olefin-based polymers, cyclic conjugated diene-based polymers, and hydrides thereof. Among these, norbornene-based polymers are particularly suitable because of their good transparency and moldability.

[0032] Examples of norbornene-based polymers include ring-opening polymers of monomers having a norbornene structure and their hydrogenated products; addition polymers of monomers having a norbornene structure and their hydrogenated products. 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 therewith. Further, 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 therewith. Among these, the hydrogenated products of ring-opening polymers of monomers having a norbornene structure are particularly preferred from the viewpoints of moldability, heat resistance, low moisture absorption, dimensional stability, light weight, etc.

[0033] As the resin containing a norbornene-based polymer, commercially available products can be used. Examples of commercially available products include "Zeonoa" manufactured by Nippon Zeon Co., Ltd.; "Arton" manufactured by JSR Corporation; "TOPAS" manufactured by TOPAS ADVANCED POLYMERS.

[0034] (1.1.3. In the form of a long film) The long film may have a single-layer structure or a multilayer structure. Further, the long film may be an unstretched film that is not stretched or a stretched film that is stretched. Examples of stretched films include longitudinally stretched uniaxially stretched films; transversely stretched uniaxially stretched films stretched in the width direction; biaxially stretched films stretched in the longitudinal and transverse directions; and obliquely stretched films stretched in the oblique direction of the film.

[0035] The length of the long film 10 is, for example, preferably 2000 m or more, more preferably 3000 m or more, and preferably 8000 m or less, more preferably 6000 m or less. When the length of the long film 10 is within the above range, the occurrence of film roll slippage and scratches can be effectively reduced.

[0036] [1.2. Core] There is no limitation on the core, and it can be the same as that used in known film rolls. The diameter of the core can be appropriately selected according to, for example, the material, use, length, etc. of the long film. As the diameter of the core, for example, it is preferably 100 mm or more, more preferably 150 mm or more, preferably 400 mm or less, and more preferably 350 mm or less.

[0037] [1.3. Shape of Film Roll] FIG. 3 is a schematic front view of a film roll according to an embodiment of the present invention as viewed from a direction perpendicular to the axial direction of the film roll. The film roll 100 has a core 1 and a long film 10, and has bead portions 102a and 102b provided at the end portions 101a and 101b in the width direction, and a flat portion 103 provided between the bead portions 102a and 102b. In FIG. 3, C represents the center in the axial direction of the film roll 100, and E1 and E2 represent the edges of the film roll 100.

[0038] The knurled portions 102 and 102b include the laminated portions 112a and 112b where the knurled regions of the long film 100 are laminated, and the laminated portions 113a and 113b of the flat regions adjacent to the knurled regions of the long film. The flat portion 103 includes the laminated portion 113c of the flat region of the long film 100. In the film roll 100, usually, the winding diameters of the laminated portions 112a and 112b of the knurled regions including a plurality of convex portions are larger than the winding diameters of the laminated portions 113a, 113b, and 113c of the flat regions not including a plurality of convex portions. Also, the winding diameters of the laminated portions 113a and 113b of the flat regions adjacent to the knurled regions become smaller toward the laminated portion 113c of the flat region located closer to the center C, and the winding diameter of the laminated portion 113c of the flat region in the flat portion becomes substantially a constant winding diameter. Such a shape of the surface of the film roll 100 has a stepped shape in which the knurled portion bulges with respect to the flat portion.

[0039] The inventors have found that the height of the stepped shape during winding of the film roll affects the occurrence of deviation and scratches. The following effects are considered for the deviation. The knurled portion of the film roll is obtained by laminating the knurled region of the long film and the flat region adjacent to the knurled region. When there is a variation in the height of the stepped shape during winding, there is also a variation in the width of the flat region of the long film constituting the knurled portion, and as a result, there is a variation in the width of the entire long film wound around the film roll. Specifically, in the portion where the height of the stepped shape is high, the width of the flat region of the long film constituting the stepped shape is larger than that in the portion where the height of the stepped shape is low, and the width of the flat region of the long film constituting the flat portion is smaller. Therefore, it is considered that deviation occurs because there are portions with different widths of the film roll in the winding direction from the core of the film roll to the outer winding. It is considered that the influence on the deviation increases as the height of the stepped shape increases.

[0040] In addition, the following effects can be considered for scratches. As described above, it is considered that the influence on the slippage increases as the height of the stepped shape increases. To avoid this, when the height of the stepped shape is reduced, in the flat portion of the film roll, since the films are likely to come into contact with each other at the laminated portion of the flat regions of the long film, it is considered that scratches are likely to occur.

[0041] Based on the above findings, the inventors defined the flange step, which is the difference in winding diameters between the flange portion and the flat portion of the film roll during winding of the film roll, from the shape profile of the film roll surface measured by a laser displacement meter, and found that by setting the height of the flange step within a predetermined range, both the occurrence of slippage and scratches can be suppressed, thereby completing the present invention.

[0042] That is, for a film roll according to an embodiment of the present invention, when the final winding length of the long film is L (m), at a winding length of L / 25 (m) or more, based on the shape profile of the film roll surface measured by a laser displacement meter, the height ΔD1 of the first flange step and the height ΔD2 of the second flange step defined by the following formula (1) and the following formula (2) are 0.1 mm or more and 1.0 mm or less. ΔD1=(D N1(MAX) -D F1(AVE) ) / 2 (1) ΔD2=(D N2(MAX) -D F2(AVE) ) / 2 (2) (In the above formula (1), D N1(MAX) is the maximum value of the diameter of one of the two flange portions of the film roll, D F1(AVE) is the average value of the diameters of the flat portions on the side of the one flange portion of the film roll. In the above formula (2), D N2(MAX) is the maximum value of the diameter of the other of the two flange portions of the film roll, D F2(AVE) is the average value of the diameters of the flat portions on the side of the other flange portion of the film roll.)

[0043] When the final winding length of the long film is L (m), in the winding length of L / 25 (m) or more, "ΔD1 and ΔD2 are 0.1 mm or more and 1.0 mm or less" means that in the entire range of the winding length of the long film from L / 25 to L (m), the maximum value and the minimum value of ΔD1, and the maximum value and the minimum value of ΔD2 are all 0.1 mm or more and 1.0 mm or less.

[0044] The measuring method of the shape profile of the film roll surface according to this embodiment will be described in detail with examples. FIG. 4 is an explanatory diagram for explaining an example of the measuring method of the shape profile of the film roll surface according to an embodiment of the present invention. As shown in FIG. 4, while the long film 10 is being wound around the core 1, a laser displacement meter 200a is installed at a position away from the surface of the film roll 100. At this time, the position of the laser displacement meter 200a is installed at a position perpendicular to the central axis 2 of the core 1 of the film roll 100. Also, let the distance from the laser displacement meter 200a to the surface of the core 1 of the film roll 100 be y1. The distance y1 can be, for example, 580 mm. Next, in the axial direction (width direction) of the film roll 100, in a predetermined range from the edge E1 of the film roll to the center C side, the distance y2 from the laser displacement meter 200a to the surface of the film roll 100 is measured. By adding the radius y3 of the core 1 to the value obtained by subtracting the obtained distance y2 from the distance y1, the distance R from the central axis 2 of the core 1 to the surface of the film roll 100, that is, the radius R of the film roll 100 is calculated. By creating a plot with the distance from the axial center C of the film roll 100 to the measurement position on the horizontal axis and the radius R of the film roll 100 on the vertical axis, a shape profile of the film roll surface as shown in FIG. 5 is obtained. The above-described shape profile is performed at a constant period in the range of L / 25 to L (m). The period can be, for example, 50 ms. Note that the measurement of the shape profile may be performed, for example, using laser displacement meters 200a and 200b to simultaneously measure the shape profile including the knurl portion 102b and the shape profile including the knurl portion 102b.

[0045] FIG. 5 is an explanatory diagram for explaining an example of the shape profile of the film roll surface. In the shape profile of the film roll surface, the flange portion and the flat portion are defined as follows. In the shape profile (curve) of the film roll, usually, there is a range where the radius R of the film roll increases from the central side in the axial direction toward the end side. Usually, this range corresponds to the laminated portion of the flat region in the flange portion of the film roll. When the slope of the tangent line of the curve in this range is α, the point where α = 0 is defined as the boundary point P between the flange portion and the flat portion of the shape profile. The central side of the film roll from the boundary point P is defined as the flat portion 103. Also, when the flange region is provided in the long film without being separated from the edge of the long film, the portion from the boundary point P to the edge of the film roll is defined as the flange portion 102. Further, when the flange region is formed at a position separated from the edge of the long film in the long film, the portion from the boundary point P to the flange region is defined as the flange portion 102.

[0046] As shown in FIG. 5, in the shape profile of the film roll surface, there may be a range where the radius R of the film roll decreases and then increases from the central side in the axial direction toward the end side. In this case, since the point where the slope α of the tangent line of the curve in the above range becomes α = 0 is the minimum value of the curve, the boundary point P is at the minimum value.

[0047] Here, since the cross-sectional peripheral shape of the film roll can usually be circular, when expressed using the diameter D of the film roll, the radius R can be expressed as D / 2.

[0048] Based on the shape profile of the film roll surface, the first flange step ΔD1 and the second flange step ΔD2, which are the winding diameter differences between the flange portion and the flat portion, are defined as follows. ΔD1=(D N1(MAX) -D F1(AVE) ) / 2 (1) ΔD2=(D N2(MAX) -D F2(AVE) ) / 2 (2) (In the above formula (1), D N1(MAX)is the maximum value of the diameter of one of the two narl parts of the film roll, D F1(AVE) is the average value of the diameter of the flat part on the side of the one narl part of the film roll. In the formula (2), D N2(MAX) is the maximum value of the diameter of the other narl part of the two narl parts of the film roll, D F2(AVE) is the average value of the diameter of the flat part on the side of the other narl part of the film roll.)

[0049] In ΔD1, D N1(MAX) is the maximum value of the diameter of the film roll in the narl part, D N1(MAX) / 2 is the maximum value of the radius of the film roll in the narl part. The above D N1(MAX) / 2 corresponds to the maximum value of R in the narl part of the aforementioned shape profile.

[0050] D F1(AVE) is the average value of the diameter of the flat part on the narl part side, D F1(AVE) / 2 is the average value of the radius of the flat part on the narl part side. D F1(AVE) / 2 corresponds to the average value of R in the flat part on the narl part side of the aforementioned shape profile. D F1(AVE) / 2 specifically corresponds to the 10-point average value obtained by measuring the radius R at 10 points on the flat part on the narl part side. The flat part on the narl part side is in the range within 0.1w from the boundary point P between the narl part and the flat part when the total width of the flat part is w. The measurement points on the flat part on the narl part side can be arbitrary, but since the position of the boundary point P may change slightly during the winding process, it is preferable to select the measurement points within the range from a position 0.005w inside the boundary point P to 0.1w inside.

[0051] For D in ΔD2 N2(MAX) / 2 and D F2(AVE) / 2, from the shape profile including the other narl part of the film roll, D in ΔD1 N1(MAX) / 2 and D F1(AVE) / 2 can be measured in the same way.

[0052] ΔD1 and ΔD2 can also be expressed, for example, by the following formulas (3) and (4) using the radius R of the film roll. ΔD1 = R N1(MAX) -R F1(AVE) (3) ΔD2 = R N2(MAX) -R F2(AVE) (4) (In the above formula (3), R N1(MAX) is the maximum value of the radius of one of the two flange portions of the film roll, and R F1(AVE) is the average value of the radius of the flat portion on the side of the one flange portion of the film roll. In the above formula (4), R N2(MAX) is the maximum value of the radius of the other of the two flange portions of the film roll, and R F2(AVE) is the average value of the radius of the flat portion on the side of the other flange portion of the film roll.)

[0053] ΔD1 and ΔD2 are each 0.10 mm or more and 1.00 mm or less. The lower limit of ΔD1 and ΔD2 may be 0.10 mm or more, may be 0.20 mm or more, may be 0.30 mm or more, or may be 0.40 mm or more. On the other hand, the upper limit of ΔD1 and ΔD2 may be 1.00 mm or less, may be 0.80 mm or less, or may be 0.60 mm or less.

[0054] The maximum value and the minimum value of ΔD1 may both be 0.10 mm or more and 1.00 mm or less. The lower limit of the difference between the maximum value and the minimum value of ΔD1 may be, for example, 0.10 mm or more, or may be 0.30 mm or more. On the other hand, the upper limit of the difference between the maximum value and the minimum value of ΔD1 may be 0.60 mm or less, or may be 0.50 mm or less.

[0055] ΔD1 and ΔD2 may be higher than each other or may be equal. However, from the viewpoint of storing the film roll well, it is preferable that ΔD1 and ΔD2 are equal. The height difference between ΔD1 and ΔD2 may be, for example, 0.05 mm or less, may be 0.04 mm or less, or may be 0.03 mm or less.

[0056] When the final winding length of the long film is L (m), at a winding length of L / 25 (m) or more, the average value of the diameters of the entire flat portion of the film roll in the shape profile of the film roll surface measured by a laser displacement meter is D FC(AVE) When defined as such, it is preferable that the height differences ΔD3 and ΔD4 at the center of the narl portion and the flat portion, defined by the following formula (5) and the following (6), are each 0.10 mm or more and 1.00 mm or less. ΔD3 = D N1(MAX) - D FC(AVE) (5) ΔD4 = D N2(MAX) - D FC(AVE) (6) (In the above formula (5), D N1(MAX) is the maximum value of the diameter of one of the two narl portions of the film roll, and in the above formula (6), D N2(MAX) is the maximum value of the diameter of the other of the two narl portions of the film roll, and in the above formulas (5) and (6), D FC(AVE) is the average value of the diameters of the entire flat portion of the film roll.)

[0057] D FC(AVE) / 2 can be the 20-point average value obtained by measuring the radius R of the film roll at 20 points in the flat portion between the boundary point of one narl portion and the flat portion and the boundary point of the other narl portion and the flat portion in the shape profile of the film roll surface. The measurement interval can be, for example, 50 mm intervals.

[0058] Figures 6(a) to (d) are diagrams showing other examples of the shape profile of the film roll surface. As the shape profile of the knurl portion on the surface of the film roll, for example, it may be a convex shape as shown in Fig. 6(a), a flat shape as shown in Figs. 6(b) and (c), or a concave shape as shown in Fig. 6(d). In the present embodiment, among these, it is preferable that the shape profile of the knurl portion is a flat shape or a convex shape. When the knurl shape of the film roll is a flat shape and a convex shape, it is easy to stably support the weight of the film roll itself, and it is easy to suppress scratch defects due to the shaking of the film roll during transportation.

[0059] That the shape profile of the knurl portion on the surface of the film roll is a convex shape means that the upper part of the shape profile is a raised shape. Also, that the shape profile of the knurl portion is a flat shape means that the upper part of the shape profile is a flat shape. Further, that the shape profile of the knurl portion is a concave shape means that the upper part of the shape profile is a sunken shape. The shape of the shape profile of the knurl portion shall be determined from its overall shape. Also, the shape profile of the knurl portion may have fine irregularities on its upper part to such an extent that it does not affect the convex shape, flat shape, and concave shape.

[0060] When the shape of the knurl portion in the surface layer of the film roll is a convex shape, as shown in Fig. 6(a), in the shape profile of the knurl portion, taking the total width of the knurl portion as W N and the range of the distance of 0.25W from the center c in the axial direction of the knurl portion to both sides as the central region 202, when there is at least one maximum value in the central region 202, and the maximum value in the central region 202 becomes the maximum value R of the radius R in the knurl portion N Rmax, it is preferable. N(MAX)

[0061] When the shape of the knurl portion is a flat shape, as shown in Fig. 6(b), (i) the shape profile of the knurl portion has two or more maximum values and one or more minimum values, and (ii) the value obtained by dividing the difference between the maximum value V N(MAX) of the maximum values and the minimum value V N(min) of the minimum values by the height ΔD of the knurl step is less than 0.3 ((V​N(MAX) -V N(min) ) / ΔD < 0.3), it is preferable to satisfy the two conditions of (i) and (ii). Further, when the shape of the bead portion is a flat shape, as shown in FIG. 6(c), the shape profile does not have distinct maximum and minimum values, and the maximum value R N(MAX) and the minimum value R N(min) of the radius R in the central region of the bead portion, the value obtained by dividing the difference by the height ΔD of the bead step is less than 0.3 ((R N(MAX) - R N(min) ) / ΔD < 0.3) is also preferable. Note that the maximum value of the maximum values refers to the value of the maximum value of the radius R among two or more maximum values, the minimum value of the minimum values refers to the value of the radius R of the minimum value when there is only one minimum value, and when there are two or more minimum values, it refers to the value of the minimum value of the radius R that is the smallest.

[0062] When the shape of the bead portion is a concave shape, for example, the shape profile of the bead portion has two or more maximum values and one or more minimum values, and the minimum value V N(min) exists in the central region 202 of the bead portion, and the value obtained by dividing the difference between the maximum value V N(MAX) of the maximum values and the minimum value V N(min) of the minimum values by the height of the bead step is 0.3 or more ((V N(MAX) - V N(min) ) / ΔD ≥ 0.3), and can take a shape such as this. In this case, the upper limit of (V N(MAX) - V N(min) ) / ΔD is, for example, (V N(MAX) - V N(min) ) / ΔD ≤ 0.7.

[0063] The shape profile of the bead portion on the film roll surface can be evaluated from the shape of the average profile per one turn of the film roll, which is obtained by sampling so that the moving average in the time direction (winding direction) is T / S points when the winding period (T seconds) and the sampling period (S seconds) of the film roll are set. The above evaluation is to evaluate whether the shape is the same over the entire region of L / 25 (m) or more when the final winding length of the long film is L (m). Also, the above-mentioned (V N(MAX) - V N(min) ) / ΔD and (RN(MAX) -R N(min) ) / ΔD is, throughout the entire measurement range of the winding length described above, (V N(MAX) -V N(min) ) / ΔD's maximum and minimum values, and (R N(MAX) -R N(min) ) / ΔD's maximum and minimum values both preferably satisfy the same relational expression.

[0064] The shape of the narl part can be adjusted, for example, by providing a difference in the height of the convex part formed in the narl region of the long film.

[0065] [2. Method for manufacturing a film roll] The film roll of the present invention includes a step (1) of winding a long film around a core, and in the step (1), using a laser displacement meter, the shape profile is measured in a range including the narl part and the flat part on the narl part side from the end of the film roll. When the final winding length of the long film is L (m), the manufacturing method can manufacture the long film by winding it so that ΔD1 and ΔD2 at a winding length of L / 25 (m) or more are 0.1 mm or more and 1.0 mm or less.

[0066] Regarding the method for measuring the shape profile, since it is the same as the content described in the section [1. Film roll] above, the description here is omitted. As a method for adjusting ΔD1 and ΔD2 within a predetermined range, for example, methods such as adjusting the winding speed, film tension, and winding method of the winding device can be mentioned.

[0067] In step (1), the winding speed (line speed) is preferably 10 m / min or more, more preferably 20 m / min or more, preferably 100 m / min or less, and more preferably 80 m / min or less.

[0068] In step (1), the winding tension (film tension) of the long film at the start of winding is preferably 10 N / m or more, more preferably 50 N / m or more, and preferably 200 N / m or less, more preferably 170 N / m or less.

[0069] In step (1), the winding tension of the long film may be changed. For example, the tension may be gradually decreased as winding progresses from the winding tension Ts at the start of winding of the long film. If the winding tension at the end of winding of the long film is Te, the tension taper ratio (%) = (Ts - Te) / Ts × 100 is preferably 5% or more, more preferably 10% or more, and preferably 50% or less, more preferably 40% or less.

[0070] In step (1), the winding method of the winding device is not limited. As the winding method, for example, a near roll may be brought into contact with the film surface of the touch winding roll. In this case, the touch pressure of the near roll is preferably 5 N / m or more, more preferably 15 N / m or more, and preferably 100 N / m or less, more preferably 80 N / m or less.

[0071] In step (1), as the winding method of the winding device, the long film may be wound while providing a gap between the film surface of the winding roll and the near roll. In this case, the gap amount is preferably 3 mm or more, more preferably 5 mm or more, and preferably 20 mm or less, more preferably 15 mm or less.

[0072] The method for manufacturing a film roll may include any step in addition to the above step (1). Examples of any step include a step of preparing a long film and a step of conveying the long film.

Example

[0073] Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the examples shown below, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

[0074] In the following description, “%” and “parts” representing amounts are on a weight basis unless otherwise specified. Also, the operations described below were performed under conditions of normal temperature and normal pressure unless otherwise specified.

[0075] [Evaluation method] (Thickness of the film) The measurement head of the infrared absorption type thickness gauge was moved along the width direction of the film, and the thicknesses at a total of 298 points were measured at intervals of 5 mm with respect to a film width of 1490 mm, and the arithmetic mean value thereof was taken as the average thickness of the film.

[0076] (Height of the narl (protrusion)) The height of the narl (protrusion) of the long film was measured by the following method. From the outermost layer of the long film, film samples of 100 mm × 100 mm including the narl region were collected from both ends. Each point of the narl applied to the long film with a laser beam was measured with a digital micrometer (manufactured by Mitutoyo Corporation). Specifically, first, the flat end portion where no narl (protrusion) was applied was sandwiched with the micrometer for zero point correction. Next, the narl (protrusion) was sandwiched with the micrometer, and the measured value was taken as the narl height. For one side end portion, the narl heights at 50 points (100 points at both ends) were measured, and the arithmetic mean value thereof was taken as the narl height of the long film.

[0077] (Heights of the narl steps ΔD1 and ΔD2) While winding the film roll, a non-contact laser displacement meter (Keyence LJ-X8400) was used to measure the shape profile of the film roll surface at a sampling period of 50 ms for 100 mm at both ends of the film roll with knurls. From the obtained shape profile of the film roll surface, the knurl step size at both ends was measured. In Examples 1 to 5 and 7 to 8, and Comparative Examples 1 to 3, since the winding length of the film roll was 5,200 m, the maximum and minimum values of ΔD1 and ΔD2 after a winding length of 208 m were determined. In Example 6 and Comparative Example 4, since the winding length of the film roll was 5,800 m, the maximum and minimum values of ΔD1 and ΔD2 after a winding length of 232 m were determined.

[0078] (Shape profile of the knurl part) The shape profile of the knurl part was measured in the range of L / 25 (m) or more when the final winding length was L (m). The shape profile of the knurl part was measured as the average profile shape per revolution of the film roll with a sampling period of 50 ms (0.05 seconds) and a moving average in the time direction (winding direction) of T÷0.05 points when the winding period of the film roll was T (seconds). The shape of the knurl part was evaluated from the overall shape of the obtained knurl shape profile. For those with a flat shape having a maximum value and a minimum value in the knurl part, and those with a concave shape in the knurl part, the maximum value V N(MAX) and the minimum value V N(min) were measured and (V N(MAX) - V N(min) ) / ΔD was calculated, and the maximum and minimum values of (V N(MAX) - V N(min) ) / ΔD were determined over the entire range of the winding length of the long film from L / 25 to L (m). Convex (convex shape): The upper part of the shape profile is raised. Flat (flat shape): The upper part of the shape profile is flat. Concave (concave shape): The upper part of the shape profile is recessed.

[0079] (End face displacement amount and winding deviation) The roll end face profile immediately after winding was obtained using a profiling gauge, and the distance was measured with a caliper. Using the measured distance as the film end face, it was graphed as shown in Fig. 7. The difference between the maximum value and the minimum value of the end face profile was defined as the "end face deviation amount" (z in Fig. 7). Also, the degree of end face deviation was evaluated as follows in A and B below. A: The end face deviation amount is less than 10 mm. B: The end face deviation amount is 10 mm or more.

[0080] (Number of scratches) After storing the wound film roll for one week, a vibration test was conducted in which an acceleration of 0.3 to 1.0 G was continuously and randomly applied in the film width direction for 60 minutes. The vibration frequency was set to 2 to 200 Hz. After the vibration test, the film roll was unwound at a line speed of 50 m / min, and the total number of abrasion scratches was evaluated with a defect detector. The illumination of the defect detector was installed so as to be a transmission scattering type, and it was set so that light could be scattered and detected when there were scratches on the film. Scratches of 0.55 mm or more were detected as one scratch.

[0081] [Example 1] (1-1) Production of raw film Pellets of an alicyclic structure-containing polymer resin (ZEONOR 1215: manufactured by Zeon Corporation, Japan) were dried at 100 °C for 5 hours. The pellets were supplied to an extruder, melted in the extruder, passed through a polymer pipe and a polymer filter, and extruded in a sheet form onto a casting drum from a T-die, cooled, and an unstretched film with a thickness of 80 μm and a width of 1600 mm was obtained.

[0082] (1-2) Film stretching The obtained unstretched film was coated with an easy-adhesion layer, and then simultaneously biaxially stretched at a stretching temperature of 135 °C with a stretching ratio of 1.15 times in the MD direction and a stretching ratio of 1.44 times in the TD direction to obtain a film with a thickness of 52 μm and a width of 1490 mm.

[0083] (1-3) Formation of dull area Using a 9.4 μm laser oscillator, CO2 laser irradiation was applied for thermal processing within a range 10 mm inside from the extended film ends, thereby imparting nicks with a nick height of 10 μm to both ends of the long film.

[0084] (1-4) Winding of the long film The long film with the nick regions formed was wound around a core having a diameter of 169 mm (radius 84.5 mm) to produce a film roll. The winding was performed such that the near roll was not in contact with the film surface of the winding roll, and the long film was wound while always maintaining a gap amount of 10 mm between the near roll and the film surface. The winding conditions were a line speed (film conveyance speed, winding speed) of 50 m / min, a winding tension of 140 N / m (20% downtaper), and a wound length of 5,200 m.

[0085] [Examples 2 and 3] Film rolls were manufactured and evaluated in the same manner as in Example 1, except that in (1-3) of Example 1, the height of the convex portions was set to 13 μm (Example 2) and 7 μm (Example 3).

[0086] [Examples 4 and 5] Film rolls were manufactured and evaluated in the same manner as in Example 1, except that in (1-4) of Example 1, the winding tensions were set to 100 N / m (20% downtaper) (Example 4) and 180 N / m (20% downtaper) (Example 5).

[0087] [Example 6] Film rolls were manufactured and evaluated in the same manner as in Example 1, except that in (1-4) of Example 1, the film was wound under the following conditions. The winding conditions were that the near roll was in contact with the film surface of the winding roll for winding, the line speed was 80 m / min, the winding tension was 100 N / m (0% downtaper), the touch pressure of the near roll was 34 N / m, and the wound length was 5,800 m.

[0088] [Example 7] In (1-3) of Example 1, except that the width of one narl region was 10 mm, the height of the convex portions formed in the range of 2.5 mm in the width direction from both ends of the narl region was 7 μm, and the height of the convex portions formed in the central region was 13 μm, a film roll was produced and evaluated in the same manner as in Example 1.

[0089] [Example 8] In (1-3) of Example 1, except that the width of one narl region was 10 mm, the height of the convex portions formed in the range of 2.5 mm in the width direction from both ends of the narl region was 13 μm, and the height of the convex portions formed in the central region was 7 μm, a film roll was produced and evaluated in the same manner as in Example 1.

[0090] [Comparative Example 1] In (1-3) of Example 1, except that the height of the convex portions was 20 μm, a film roll was produced and evaluated in the same manner as in Example 1.

[0091] [Comparative Example 2] In (1-3) of Example 1, except that the height of the convex portions was 16 μm, and in (1-4), except that the winding tension was 180 N / m, a film roll was produced and evaluated in the same manner as in Example 1.

[0092] [Comparative Example 3] In (1-3) of Example 1, except that the height of the convex portions was 3 μm, and in (1-4), except that the winding tension was 100 N / m, a film roll was produced and evaluated in the same manner as in Example 1.

[0093] [Comparative Example 4] In (1-3) of Example 1, except that the height of the convex portions was 3 μm, a film roll was produced and evaluated in the same manner as in Example 6.

[0094] [Results] The results are shown in Tables 1 to 3. The abbreviations in Tables 1 to 3 have the following meanings. "Touch": Winding is performed by bringing the near roll into contact with the film surface of the winding roll. "Gap": Winding is performed while keeping the gap amount between the near roll and the film surface constantly at 10 mm without bringing the near roll into contact with the film surface of the winding roll. "Winding tension": Tension (Ts) at the start of winding

[0095] [Table 1]

[0096] [Table 2]

[0097] [Table 3]

[0098] In Table 3, regarding the presence or absence of the maximum value and the minimum value, "both present" means having both the maximum value and the minimum value. In Example 7, a maximum value where the radius R is the maximum value was confirmed in the central region of the narl part. Also, in Example 8, the minimum value of the minimum value was confirmed in the central region of the narl part.

[0099] As shown in Tables 1 and 2, in Examples 1 to 8 where ΔD1 and ΔD2 are within the range of 0.1 mm to 1.0 mm, it was confirmed that the end face displacement of the film roll was suppressed and the occurrence of scratches was suppressed. On the other hand, in Comparative Examples 1 and 2 where ΔD1 and ΔD2 exceed 1.0 mm, although the occurrence of scratches was suppressed, it was difficult to sufficiently suppress the end face displacement. Also, in Comparative Examples 3 and 4 where ΔD1 and ΔD2 are less than 0.1 mm, although the occurrence of end face displacement was suppressed, it was difficult to sufficiently suppress the occurrence of scratches.

[0100] In Examples 1 to 8, when the shape profile of the flange portion is a flat shape and a convex shape, it was confirmed that it is particularly effective in suppressing the occurrence of scratches compared to the concave shape.

Explanation of Signs

[0101] 1 Core 10 Long film 10U Surface 11 End of long film 12a and 12b Flange region 13 Flat region 14 Convex part e1 and e2 Edges of long film 100 Film roll C Center in the axial direction of film roll E1 and E2 Edges of film roll 101a and 101b Ends 102a and 102b Flange parts 103 Flat part 104a and 104b Flat parts on the flange part side 112a and 112b Laminated part of flange regions 113a, 113b, 113c Laminated parts of flat regions

Claims

1. A film roll having a core and a long film wound around the core, The long film has two nail regions provided at both ends in the width direction and including a plurality of convex portions, and a flat region provided between the two nail regions. The nail region is a strip-shaped region extending parallel to the longitudinal direction of the long film. The film roll has two nail portions provided at both ends in the width direction and including a laminated portion where the nail regions of the long film are laminated and a laminated portion of a flat region adjacent to the nail region, and a flat portion provided between the two nail portions and including a laminated portion where the flat region of the long film is laminated. When the final winding length of the long film is L (m), in the entire winding length of L / 25 (m) or more, Based on the shape profile of the film roll surface measured by a laser displacement meter, the height ΔD1 of the first nail step and the height ΔD2 of the second nail step defined by the following formula (1) and the following formula (2) are 0.1 mm or more and 1.0 mm or less. A film roll. ΔD1 = (DN1(MAX) - DF1(AVE)) / 2 (1) ΔD2 = (DN2(MAX) - DF2(AVE)) / 2 (2) (In the formula (1), DN1(MAX) is the maximum value of the diameter of one of the two nail portions of the film roll, and DF1(AVE) is the average value of the diameters of the flat portions on the side of the one nail portion of the film roll. In the formula (2), DN2(MAX) is the maximum value of the diameter of the other of the two nail portions of the film roll, and DF2(AVE) is the average value of the diameters of the flat portions on the side of the other nail portion of the film roll.)

2. The film roll according to claim 1, wherein the shape profile of the nail portion on the film roll surface is a convex shape or a flat shape.

3. The film roll according to claim 1 or 2, wherein the resin material of the long film contains a cycloolefin polymer.

4. The film roll according to any one of claims 1 to 3, wherein the height of the convex portion included in the knurl region of the long film is 4 μm or more and 15 μm or less.

5. The film roll according to any one of claims 1 to 4, wherein the ratio of the width of the knurl region to the total width of the long film is 0.3% or more and 5.0% or less.

6. The film roll according to any one of claims 1 to 5, wherein the average thickness of the long film in the flat region is 10 μm or more and 100 μm or less.

7. The film roll according to any one of claims 1 to 6, wherein the length of the long film is 2000 m or more and 8000 m or less.

8. A method for manufacturing a film roll according to any one of claims 1 to 7, comprising: Measuring the shape profile of the surface of the film roll in a range including the knurl portion and the flat portion on the knurl portion side from the edge of the film roll using a laser displacement meter, and when the final winding length of the long film is L (m), winding the long film so that ΔD1 and ΔD2 in the entire winding length of L / 25 (m) or more are 0.1 mm or more and 1.0 mm or less.

9. The method for manufacturing a film roll according to claim 8, wherein the long film is wound at a winding speed of 10 m / min or more and 100 m / min or less.

10. Using a winding device having a near roll, The method for manufacturing a film roll according to claim 8 or 9, wherein the winding method of the winding device is a method of winding the long film by bringing the near roll into contact with the film surface on the winding roll of the long film.

11. Using a winding device having a near roll, The method for manufacturing a film roll according to claim 8 or 9, wherein the winding method of the winding device is a method of winding the long film while providing a gap between the film surface on the winding roll of the long film and the near roll.

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