WO2012124305A1

WO2012124305A1 - Film winding core, and wound film body using same

Info

Publication number: WO2012124305A1
Application number: PCT/JP2012/001670
Authority: WO
Inventors: 俊祐能見; 俊一郎佐柳
Original assignee: 日東電工株式会社
Priority date: 2011-03-11
Filing date: 2012-03-09
Publication date: 2012-09-20
Also published as: CN103415456A; JP2012188252A; EP2684828A1; KR20140012711A; EP2684828A4; US20140001306A1

Abstract

A film winding core (10) has a cylindrical winding core main body (12), and a plurality of film support portions (14) that protrude from the outer peripheral surface (12p) of the winding core main body (12). The plurality of film support portions (14) support a film (18) at position detached from the outer peripheral surface (12p) of the winding core main body (12). The support portions (14) comprise an elastic material such as sponge, rubber, or foam, and are in the shape of a semi-cylinder, a rectangular column, or a hollow semi-cylinder. The film (18) and the winding core main body (12) do not adhere to each other, even if the film (18) wrapped around the winding core (10) contracts while in storage.

Description

Film winding core and film winding body using the same

The present invention relates to a film winding core and a film winding body using the same.

A long film is manufactured by a known method such as extrusion molding, wound around a cylindrical core, and stored and shipped. When the film is wound around a cylindrical core and stored, the film may be distorted (deformed), which may hinder the unwinding of the film. Such a problem is pointed out in Patent Document 1, for example.

Patent Document 1 describes a winding core configured to prevent distortion of a belt-like object due to winding tightening. Specifically, after winding the strip around the core so that the outer periphery of the core and the strip are in close contact, the core is reduced in the radial direction. Moreover, after expanding a core in the radial direction and improving the adhesiveness of the outer peripheral part of a core and a strip | belt-shaped object, a strip | belt-shaped object is unwound from a core.

Japanese Patent Laying-Open No. 2009-111387 (FIGS. 5 to 10)

Since the core described in Patent Document 1 has a relatively complicated mechanism, it is not suitable for a business form in which a film wound around the core is provided to the customer together with the core.

The object of the present invention is to provide a simple technique for preventing problems during unwinding of a film.

That is, the present invention
A core for winding a long film,
A core body having a cylindrical shape;
The core body is provided at each of a plurality of positions along the circumferential direction of the core body so as to be provided around the core body and to support the film at a position away from the outer peripheral surface of the core body. A plurality of film support portions that individually protrude from the outer peripheral surface and are each made of a material that can be deformed when the film is wound around the core;
A winding core for film winding is provided.

In another aspect, the present invention provides:
The film winding core of the present invention;
A film wound on the film winding core of the present invention;
A film winding body is provided.

According to the knowledge of the present inventors, the film is distorted based on the following mechanism. Although the long film depends on its production method, it has a considerable thickness variation (thickness variation). When such a film is wound on a conventional cylindrical core, the thick part swells outward compared to the thin part. Then, since the tension is concentrated on the thick part, the thick part is stretched in the longitudinal direction. On the other hand, sufficient tension is not applied to the thin part, so that a so-called gapping occurs in some cases. “Wound nest” means a space formed between an inner film and an outer film. When the film is stored in a temperature environment where shrinkage occurs after the film is wound on the winding core, the portion where the wound is generated shrinks in the longitudinal direction so as to eliminate the wound. As a result, the distortion between thick and thin portions increases. That is, a difference in length in the longitudinal direction occurs between the thick portion and the thin portion.

This distortion is stored in the film. Therefore, the film is unwound from the core while maintaining the distortion. Then, sufficient tension is not applied to the thick part, and the thick part is slackened. Such a phenomenon appears remarkably when the tension to be applied to the film during unwinding is small. The slack generated in the film causes a film transport error, and decreases the yield of the product using the film and the utilization rate of the film.

According to the present invention, a plurality of film support portions are provided around the core body. Since the film support part protrudes from the outer peripheral surface of the core body, the film is supported by the film support part. Therefore, it can avoid that a film adheres to a core main body between two film support parts adjacent to each other in the circumferential direction. Thereby, it is possible to prevent distortion from being stored in the film as much as possible. Furthermore, the film support part is comprised with the material which can deform | transform when a film is wound up. By deforming the film support portion, it is possible to reduce or cancel the influence of uneven thickness of the film.

As described above, according to the core of the present invention, distortion caused by uneven thickness can be suppressed. Accordingly, it is possible to prevent the film from being bent or slackened during unwinding. As a result, it becomes possible to run the film stably at the time of unwinding, and the occurrence rate of production failure (conveyance error) can be greatly reduced. The yield of products using films and the utilization rate of films are also improved.

The perspective view of the core for film winding which concerns on embodiment of this invention 1 is a cross-sectional view taken along line II-II of the core shown in FIG. Cross-sectional view of a wound film body using the core shown in FIG. Schematic showing the preferred protrusion height of the film support Cross-sectional view of a winding core according to a modification Cross-sectional view of a winding core according to another modification Further, a cross-sectional view of a winding core according to another modification

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Hereinafter, in this specification, the film winding core is simply abbreviated as “core”.

As shown in FIGS. 1 and 2, the core 10 includes a core body 12, a pair of bearing portions 16, and a plurality of film support portions 14. As shown in FIG. 3, the film winding body 100 includes a winding core 10 and a long film 18 wound around the winding core 10. The core 10 can be rotated about the rotation axis O. The rotation axis O is an axis that passes through the center of the core body 12.

The core body 12 has a cylindrical shape. For example, the core body 12 can be composed of a cylindrical body having both ends open. The shape of the cross section of the core body 12 is not particularly limited, and may be circular or polygonal as in this embodiment. According to the core 10, the film 18 is directly supported by the film support portion 14. Furthermore, as will be described later, the influence of the uneven thickness of the film 18 is canceled by the film support portion 14. Therefore, high dimensional accuracy is not required for the core body 12.

The material of the core body 12 is not particularly limited. The core body 12 can be made of resin, metal, ceramic, glass, or a combination thereof. It is desirable that the core body 12 is not easily deformed when the film 18 is wound around the core 10. Typically, a thermoplastic resin such as polycarbonate, polypropylene, polyethylene, acrylonitrile-butadiene-styrene copolymer, polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polystyrene, polyvinyl chloride or the like is used in a known manner, for example, an injection molding method. Thus, the core body 12 can be obtained.

The film support portion 14 is a portion provided around the core body 12, and in the circumferential direction of the core body 12 so that the film 18 can be supported at a position away from the outer peripheral surface 12 p of the core body 12. At each of the plurality of positions along the center, the core body 12 protrudes from the outer peripheral surface 12p of the core body 12 outward in the radial direction. According to the film support part 14, it is possible to avoid the film 18 from being in close contact with the core body 12 between the film support parts 14 adjacent to each other in the circumferential direction. Thereby, distortion can be prevented from being stored in the film 18.

The film support 14 is made of a material that can be deformed when the film 18 is wound around the core 10. In this embodiment, the film support part 14 is comprised with the material which can be elastically deformed. When the film support portion 14 can be elastically deformed, a sufficient frictional force can be generated between the film support portion 14 and the film 18. Accordingly, when the film 18 is unwound and when the film 18 is wound, the core 10 can be prevented from spinning. Moreover, when the film support part 14 has moderate elasticity or cushioning property, the influence by the uneven thickness of the film 18 can be reduced or offset more effectively.

Typically, at least one material selected from the group consisting of sponge, rubber, and foam can be used as the material of the film support portion 14. Any of these materials can be obtained at low cost and can be easily processed. Moreover, according to these materials, sufficient frictional force can be exerted between the film 18 and the film support part 14. For example, urethane foam is recommended as a material for the film support portion 14 because it has the above-described characteristics in a well-balanced manner. Examples of the material having appropriate rebound resilience include natural rubber, nitrile rubber, silicone rubber, and foams thereof. In addition, polyethylene, EVA (ethylene vinyl acetate copolymer), EPDM (ethylene-propylene-diene rubber), fluororubber, and foams thereof can also be used. The film support portion 14 can be fixed to the core body 12 by a known method such as adhesion or welding.

In addition, it is not essential that the entire film support portion 14 is made of the above-described material. Only a part of the film support part 14, for example, a part in contact with the film 18 may be made of the material described above.

In the present embodiment, the film support portions 14 are arranged at equal intervals (equal angular intervals) in the circumferential direction of the core body 12. When the film support portions 14 are arranged at equal intervals in the circumferential direction, the uniformity of the load applied to the film 18 in the longitudinal direction of the film 18 is improved. This is advantageous for suppressing distortion.

As shown by a broken line in FIG. 4, a virtual polygon PL having a minimum area surrounding all the film support portions 14 is defined in a cross section perpendicular to the rotation axis O. The position of the film support portion 14, the number of film support portions 14, and the protrusion height h of the film support portion 14 from the outer peripheral surface 12 p of the core body 12 so that the core body 12 is accommodated inside the polygon PL. Can be adjusted. When satisfying such requirements, it can be avoided that the film 18 is strongly pressed against the core body 12. For example, the core 10A shown in FIG. 5A includes film support portions 14 provided at equal intervals in eight locations in the circumferential direction.

Further, the film support portion 14 is provided so as to extend from one side surface of the core body 12 toward the other side surface. The longitudinal direction of the film support portion 14 is parallel to the rotation axis O when the winding core 10 is rotated, and is perpendicular to the longitudinal direction of the film 18. According to such a configuration, a uniform supporting force can be exerted on the film 18 in the width direction of the film 18.

In the present embodiment, the film support portion 14 has a semi-cylindrical shape. Thereby, the film 18 can be supported on a moderately wide surface. This is preferable from the viewpoint of preventing local deformation of the film 18. A core 10B shown in FIG. 5B includes a film support 24 having a hollow semi-cylindrical shape. The core 10C shown in FIG. 5C includes a film support portion 34 having a prismatic shape. These

film support portions

24 and 34 can also be suitably employed as those having the same effect as the film support portion 14. In particular, as shown in FIG. 5B, since the film support 24 having a hollow structure can be easily elastically deformed, an effect of alleviating or canceling the influence of uneven thickness of the film 18 can be sufficiently expected. In the cross section perpendicular to the rotation axis O, the outer peripheral surface of the

film support portion

14 or 24 has a curvature smaller than the curvature of the outer peripheral surface 12p of the core body 12.

The bearing portion 16 is attached to both side surfaces of the core body 12 and is a portion into which a shaft (not shown) used when the core 10 is rotated is inserted. The winding core 10 can be smoothly rotated by the bearing portion 16. The bearing portion 16 has the same outer shape as the core body 12. However, the bearing portion 16 may have a diameter larger than the diameter of the core body 12, that is, the bearing portion 16 may extend to the outside of the core body 12.

In the present embodiment, the bearing portion 16 is composed of a disc-shaped flange having a bearing hole 16h. The bearing portion 16 may be integrated with the core body 12 or may be detachable from the core body 12. In the former case, the bearing portion 16 and the core body 12 can be integrated by a known method such as welding or adhesion. In the latter case, a fitting structure between the core body 12 and the bearing portion 16 can be provided. When the bearing portion 16 is detachable, the pair of bearing portions 16 can be used as a common member for many cores 10, so that the cost of the core 10 can be reduced. In addition, if the product obtained by removing the bearing portion 16 from the film winding body 100 is delivered to the customer, a reduction in transportation cost due to weight reduction can be expected. Of course, the bearing portion 16 is not essential, and it is possible to rotate the core 10 by directly inserting the shaft into the core body 12.

It should be noted that the “bearing portion 16” in this specification may not have the function of supporting the shaft, to be precise. The term “bearing portion” is used to mean “a portion having a through hole (bearing hole 16h) for installing the core 10 on the shaft”.

Since the core 10 of this embodiment does not have a mechanical movable part, it can be manufactured at low cost.

As shown in FIG. 3, the film winding body 100 has a polygonal shape, typically a regular polygonal shape, as a whole in a cross section perpendicular to the rotation axis O (or in plan view). In the film winding body 100, a gap SH is formed between the outer peripheral surface 12 p of the core body 12 and the film 18. Of the film 18 wound around the core 10, a portion that is not supported by the film support portion 14 is slightly slackened toward the core body 12. In this state, the film 18 may be completely separated from the core body 12, or the film 18 may be in contact with the outer peripheral surface 12p to the extent that the effect of suppressing distortion is not significantly lost.

The material, structure, and dimensions of the film 18 to be wound around the core 10 are not particularly limited. However, when the core 10 of the present embodiment is used for winding a film having an essentially uneven thickness, a very high distortion suppressing effect can be obtained. For example, a film manufactured using an extrusion apparatus equipped with a T-die has a substantially constant thickness distribution in the width direction, regardless of which part in the longitudinal direction is measured. For example, it is assumed that there is a thickness difference of about 1 μm between one end and the other end in the width direction. When such a film is wound around a conventional cylindrical winding core 1000 times, a difference in diameter of about 2 mm occurs between one end and the other end of the film winding body. Thus, even if there is a slight uneven thickness, the greater the number of windings, the greater the difference in the diameter of the film winding body, and the distortion due to uneven thickness is stored in the film, causing problems during unwinding ( The probability of occurrence of a conveyance error) typically increases.

Also, once the strain is stored, the core 10 of the present embodiment is particularly effective for winding a film that is difficult to remove. Such a film is flexible and typically has a thickness on the order of micrometers (eg 2-100 μm).

In general, there are few cases where a film having uneven thickness greatly affects the quality of a final product, for example, a secondary battery. As described above, even if there is a thickness variation of about ± 1 μm in a film having a target thickness of 20 μm, if the other characteristics of the film satisfy the standard, the quality of the final product is It is unlikely that variations will have an effect. Certainly, if the film has a completely uniform thickness, it is expected that problems during unwinding due to uneven thickness are unlikely to occur. However, it is extremely difficult to reduce the variation of ± 1 μm to ± 0.1 μm by improving the film manufacturing method, which is not practical. According to the present invention, it is possible to prevent the occurrence of defects due to uneven thickness by improving the core instead of improving the film itself.

As an example of a film manufactured using an extrusion apparatus equipped with a T die, a resin porous membrane can be mentioned. Examples of the resin porous membrane include a porous membrane made of polyolefin, fluororesin, polyurethane, polyamide, polyester, polyimide, polyamideimide, epoxy or the like. Examples of the polyolefin include polyethylene and polypropylene. Examples of the fluororesin include polytetrafluoroethylene. The resin porous film made of polyimide, polyamideimide or epoxy may be a thermosetting film. These porous resin membranes can be widely used in applications such as electrochemical element separators, waterproof breathable membranes, dust collection filters, and low dielectric substrates.

Moreover, the film 18 may have the adhesion layer and does not need to have the adhesion layer. However, a film that does not have an adhesive layer is more suitable as a target for use of the core 10 of the present embodiment. A film having an adhesive layer generally requires a strong tension to once peel off the adhered film, so even if some distortion remains in the film, it is unlikely to cause a transport error. On the other hand, in the case of a film that does not have an adhesive layer, in particular, a film in which both the front surface and the back surface have slidability, the film is often unwound and used at a low tension and at a high speed. The higher the unwinding speed, the higher the probability of occurrence of a transport error. Therefore, the use of the core 10 of this embodiment is particularly recommended as the core of a film that does not have an adhesive layer.

Claims

A core for winding a long film,
A core body having a cylindrical shape;
The core body is provided at each of a plurality of positions along the circumferential direction of the core body so as to be provided around the core body and to support the film at a position away from the outer peripheral surface of the core body. A plurality of film support portions that individually protrude from the outer peripheral surface and are each made of a material that can be deformed when the film is wound around the core;
A winding core for film winding.
The film winding core according to claim 1, wherein the material is an elastically deformable material.
The film winding core according to claim 1, wherein the material includes at least one selected from the group consisting of sponge, rubber, and foam.
The film winding core according to claim 1, wherein the film support portions are arranged at equal intervals in the circumferential direction.
The position of the film support portion and the film support so that the core body is accommodated inside a polygon with the smallest area surrounding all the film support portions in a cross section perpendicular to the rotation axis when rotating the core. The film winding core according to claim 1, wherein the number of the parts and the protrusion height of the film support part from the outer peripheral surface of the core body are adjusted.
The film support portion is provided in a form extending from one side surface of the core body toward the other side surface,
The film winding core according to claim 1, wherein a longitudinal direction of the film support portion is parallel to a rotation axis when the winding core is rotated.
The film winding core according to claim 1, wherein the film support portion has a shape of a semi-cylinder, a prism, or a hollow semi-cylinder.
The film winding core according to claim 1, further comprising a pair of bearing portions attached to both ends of the core body and into which shafts used for rotating the core are inserted.
The film winding core according to claim 8, wherein the bearing portion includes a pair of flanges having a bearing hole and detachable with respect to the core body.
A film winding core according to claim 1;
A long film wound around the film winding core;
A film winding body comprising:
The film winding body according to claim 10, wherein the film is a film manufactured using an extrusion apparatus equipped with a T die.
The film winding body according to claim 11, wherein the film is a resin porous membrane.