TW202302437A - Winding core, raw roll, and manufacturing method of raw roll - Google Patents

Abstract

An objective of the Present is to provide a winding core and the like that is capable of reducing a dent of film caused by the seam between cushioning materials and a step mark of film caused by the step of end face in the longitudinal direction of the film. A winding core (100) includes a cylindrical body (10), a cushioning layer (40) covers outer peripheral surface of the cylindrical body (10), and an adhesive member (30) that is arranged between the outer peripheral surface of the cylindrical body (10) and the cushioning layer (40). The 25% compressive stress of the buffer layer (40) is 80 to 120 kPa, and the buffer layer (40) is a foamed resin layer containing 50% by mass or more of an ethylene-vinyl acetate copolymer.

Description

Winding core, raw material reel and method for manufacturing raw material reel

The invention relates to a winding core, a raw material reel, and a manufacturing method of the raw material reel.

When conveying or storing a long film (film), generally, the film is wound up on a cylindrical core to form a roll.

As for the winding core used at this time, as described in patent document 1, the winding core which has a cylindrical body and the cushioning material which covers the outer peripheral surface of a cylindrical body is known.

[Prior Art Literature]

[Patent Document]

[Patent Document 1] Japanese Patent No. 3964892

However, in conventional winding cores, there are cases where the surface of the film to be wound is sunken due to the seam of the buffer material on the outer peripheral surface of the cylinder, or the long side of the film is caused to be depressed. The level difference of the direction end face causes a level difference mark on the part wound on the level difference.

The present invention was developed in view of the above-mentioned problems, and the object is to provide a film that can reduce the sag of the film caused by the joint between the buffer materials and the step mark of the film caused by the step of the end surface in the longitudinal direction of the film. The roll core and so on.

A winding core according to an aspect of the present invention includes: a cylindrical body; a buffer layer covering the outer peripheral surface of the cylindrical body; and an adhesive member disposed between the outer peripheral surface of the cylindrical body and the buffer layer. The 25% compressive stress of the aforementioned buffer layer is 80 to 120 kPa; the aforementioned buffer layer is a foamed resin layer containing more than 50% by mass of ethylene/vinyl acetate copolymer.

The aforementioned buffer layer may have a thickness of, for example, 0.5 to 3 mm.

The aforementioned adhesive member may be, for example, a single-layer adhesive layer.

The said adhesive member may have, for example, a pair of adhesive layers, and the base material layer arrange|positioned between the said pair of adhesive layers.

The aforementioned adhesive layer may be, for example, an acrylic adhesive layer.

The winding core according to one aspect of the present invention is used for winding up optical films, for example.

A raw material roll according to one aspect of the present invention includes: the above-described core; and an optical film wound on the outer peripheral surface of the core.

The manufacturing method of the raw material roll of one aspect of the present invention includes the step of winding the optical film on the outer peripheral surface of the above-mentioned core.

According to the present invention, it is possible to provide a winding core capable of reducing sagging of the film due to seams between buffer materials and step marks of the film due to step differences of the end faces in the longitudinal direction of the film.

10: Cylindrical body

20: Protruding member

22: Large diameter tube part

24: small diameter barrel

30: Adhesive components

34: Substrate layer

32,36: Adhesive layer

40: buffer layer

50: laminated body

100: roll core

F: film

IE: inner peripheral side

Q: angle (step difference)

QQ: Segment mark

T: Adhesive tape

Y: seam

YY: sunken

FIG. 1 is a perspective view of a winding core 100 according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view of the central portion in the axial direction of the winding core of Fig. 1 .

3( a ) and FIG. 3( b ) are cross-sectional views each showing an example of the adhesive member 30 .

4 is a schematic cross-sectional view illustrating a dent YY caused by a seam Y of a laminate 50 in a film F wound on a core 100 .

5 is a schematic cross-sectional view illustrating step marks QQ of the film F wound on the core 100 due to the angle Q of the inner peripheral edge IE of the film F.

(core)

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a winding core 100 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the central portion of the winding core in the axial direction.

The winding core 100 of this embodiment mainly includes: a cylindrical body 10 , a laminated body 50 (adhesive member 30 and buffer layer 40 ), and a boss member 20 .

The cylindrical body 10 is a cylinder having a circular cross section. The outer diameter of the cylindrical body 10 may be, for example, 70 to 400 mm. The thickness of the cylindrical body 10 may be 2 to 10 mm. The axial length of the cylindrical body 10 can be appropriately adjusted according to the length of the film to be taken up, for example, it can be 300 to 2500 mm.

The material of the cylindrical body 10 is not particularly limited, and may be, for example, metal such as aluminum alloy; fiber-reinforced resin, polyvinyl chloride resin, ABS resin. An example of an aluminum alloy is an AL-MG-SI alloy such as A6061. Examples of fibers constituting the fiber-reinforced resin are paper fibers, glass fibers, and carbon fibers. Examples of the resin constituting the fiber-reinforced resin are epoxy-based resins and phenol-based resins (bakelite). These materials have a high Young's modulus and are easy to obtain strength even if they are lightweight.

The laminated body 50 is wound around the outer peripheral surface of the cylindrical body 10 along the circumferential direction. The laminated body 50 has the adhesive member 30 and the buffer layer 40 in this order from the cylindrical body 10 side.

The laminated body 50 is wound around the cylindrical body 10 so as not to overlap each other, and the laminated body 50 has a seam Y in which one end face and the other end face face each other on the outer peripheral surface of the cylindrical body 10 . In the state where the film is not wound, the interval of the seam Y (that is, the interval between the facing end surfaces of the laminate 50 ) may be the same or different over the entire axial length of the cylindrical body 10 .

In the area where the film is taken up, the maximum interval between the seams Y may be 5 mm or less, preferably 2 mm or less, more preferably 1 mm or less. In addition, the interval of the seam Y is preferably 0 mm, but may be 0.3 mm or more, or may be 0.5 mm or more.

The buffer layer 40 is provided on the cylindrical body so as to cover the outer peripheral surface of the cylindrical body 10 . The buffer layer has a buffering effect, that is, it has elasticity and has the function of absorbing shock.

The buffer layer 40 is a layer of a foamed resin containing 50% by mass or more of an ethylene/vinyl acetate copolymer. The 25% compressive stress of the buffer layer 40 is 80 to 120 kPa. Buffer layer 40 also The ethylene/vinyl acetate copolymer may contain 70 mass % or more, and may contain 80 mass % or more. The buffer layer 40 may contain 100% by mass or less of an ethylene/vinyl acetate copolymer.

The 25% compressive stress is the stress necessary to reduce the thickness of the buffer layer 40 by 25% of the full thickness. The 25% compressive stress can be controlled by the content of ethylene/vinyl acetate copolymer, expansion ratio, etc. In addition, the 25% compressive stress is measured based on JISK 6767. The expansion ratio may be, for example, about 5 times to 20 times.

The thickness of the buffer layer 40 is not particularly limited, and may be, for example, 0.3 to 10 mm, preferably 0.5 to 3 mm. The thickness is the value measured when the stress is zero.

The adhesive member 30 is disposed between the cylindrical body 10 and the buffer layer 40 . The adhesive member 30 is peelable, and can be peeled from the cylindrical body 10 together with the buffer layer 40 .

FIG. 3( a ) and FIG. 3( b ) each show an example of the adhesive member 30 .

In FIG. 3( a ), the adhesive member 30 is a single-layer adhesive layer 32 . One side of the adhesive layer 32 is in contact with the cylindrical body 10 , and the other side of the adhesive layer 32 is in contact with the buffer layer 40 .

The adhesive layer 32 includes, for example, (meth)acrylic adhesives, polyurethane adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, and polyether adhesives. Adhesives, fluorine-based adhesives, rubber-based adhesives, etc. Among them, it is preferable to use a (meth)acrylic adhesive from the viewpoints of transparency, adhesive force, reworkability, and the like.

The thickness of the adhesive layer 32 can be set to, for example, 5 to 50 μm.

In FIG.3(b), the adhesive member 30 has a pair of adhesive agent layers 32,36, and the base material layer 34 arrange|positioned between a pair of adhesive agent layers 32,36. The upper surface of the adhesive layer 32 is in contact with the lower surface of the buffer layer 40 , and the lower surface of the adhesive layer 32 is in contact with the upper surface of the base material layer 34 . The upper surface of the adhesive layer 36 is in contact with the lower surface of the substrate layer 34, and the lower surface of the adhesive layer 36 is in contact with the cylinder. The outer peripheral surface of the body 10 is in contact. The thickness and material of the adhesive layers 32 and 36 of this type can be set to be the same as those of the adhesive layer 32 of the type shown in FIG. 3( a ). In addition, in a pair of adhesive layers 32, 36, the thickness and material of the adhesive layer 32 and the adhesive layer 36 may be the same or different.

The substrate layer 34 includes, for example, polyolefin-based resins such as polyethylene and polypropylene; cyclic polyolefin-based resins such as norbornene-based polymers; polyethylene terephthalate, polyethylene naphthalate, etc. Polyester resins such as esters; (meth)acrylic resins such as (meth)acrylic acid and polymethyl (meth)acrylate; cellulose triacetate, cellulose diacetate and cellulose acetate propionate, etc. Cellulose ester resins; Vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; Polycarbonate resins; Polystyrene resins; Polyarylate resins; Polyethylene resins; Polyether resins ; polyamide-based resins; polyimide-based resins; polyetheretherketone-based resins; polyphenylene sulfide-based resins; polyoxyxylene-based resins;

The thickness of the substrate layer 34 may be 1 to 100 μm, preferably 20 to 50 μm.

As shown in FIG. 3( a ), when the adhesive member 30 is a single layer, the structure is simple, so the manufacture is easy, and the manufacturing cost of the winding core can be suppressed.

On the other hand, as shown in Figure 3(b), when the adhesive member 30 has a three-layer structure, the adhesive layer 32 can use a material with strong adhesion to the buffer layer 40, and the adhesive layer 36 can be used with the cylindrical body. 10 is a material with strong adhesion, so it is easy to improve the bonding strength between the buffer layer 40 and the cylindrical body 10 . In addition, when the buffer layer 40 lost after the core is used is peeled off from the cylindrical body 10, the buffer layer 40 is difficult to be damaged due to the existence of the base layer 34, and the buffer layer 40 and the base layer 34 can be easily separated. Peel off from the cylinder 10 together. Accordingly, replacement of the buffer layer 40 is facilitated, and reuse of the cylindrical body 10 is also facilitated.

In FIG. 1 , protruding members 20 are respectively fitted into both ends of the cylindrical body 10 in the axial direction. The protruding member 20 has a large-diameter cylindrical portion 22 housed in the cylindrical body 10 and a small-diameter cylindrical portion 24 whose outer diameter is smaller than that of the large-diameter portion. The outer diameter of the large-diameter cylindrical portion 22 can be increased without changing the outer diameter of the small-diameter cylindrical portion 24 of the protruding member 20 at both ends, and the radius of curvature of the film in the coiled state can be increased, so that it is easier to suppress the thickness of the film. Curl and segment marks.

The material of the protruding member 20 can be appropriately selected in the same manner as the cylindrical body.

(Manufacturing method of winding core)

Next, an example of the manufacturing method of the above-mentioned winding core 100 is demonstrated.

A laminated body 50 in which the buffer layer 40 and the adhesive member 30 are laminated, and the cylindrical body 10 are prepared. The outer bonding surface of the adhesive member 30 of the laminate 50 is preferably protected with a release sheet in advance. The size of the laminated body 50 is preliminarily cut so that the length of one circumference of the outer peripheral surface of the cylindrical body 10 x the axial length of the cylindrical body.

The release sheet on the adhesive surface of the cut laminate 50 is peeled off, and the laminate 50 is pasted on the outer peripheral surface of the cylindrical body 10 . At this time, the laminated body 50 is pasted on the outer peripheral surface of the cylindrical body 10 so that the end faces of the laminated body 50 face each other and the laminated bodies do not overlap each other. In this way, the above-mentioned winding core 100 can be manufactured.

Various films can be wound on the core 100 of this embodiment. Examples of the film are optical films such as polarizing plates, retardation films, and protective films. The material of the protective film may be the same material as that of the above-mentioned base material layer 34 . The thickness of the optical film can be set to, for example, 25 to 300 μm. The length of the film is, for example, 30 to 10000 m.

By winding the film on the outer peripheral surface of the buffer layer 40 of such a core 100, raw material rolls of various films can be obtained.

(effect)

According to the core of this embodiment, it has a specific 25% compressive stress and a foamed resin layer with a specific composition as a buffer layer, so it can reduce the sag of the film caused by the seam between the buffer materials, and the risk of damage. The step mark of the film caused by the step difference of the end face of the film in the longitudinal direction.

The present invention is not limited to the above-described embodiments, and various modifications are possible.

For example, the shape of the cylindrical body, the protruding member, etc. is not limited, and can be appropriately deformed in accordance with the supporting device of the winding core used. In addition, the core may not have the protruding member.

[Example]

(Example 1)

A cylindrical body made of aluminum alloy with an outer diameter of 252 mm and a length of 1360 mm was prepared. Fix the protruding members to both ends of the cylinder.

A foamed resin layer (sponge sheet: thickness 2 mm) containing 94% by mass of an ethylene/vinyl acetate copolymer was prepared as a buffer layer. The 25% compressive stress of the buffer layer is 100kPa.

An acrylic pressure-sensitive adhesive layer (thickness: 20 μm) with a release sheet was pasted on the buffer layer to obtain a laminate. Cut the laminated body according to the area of the outer peripheral surface of the cylindrical body. The release sheet was peeled off from the cut laminate, and the buffer layer was pasted on the outer peripheral surface of the cylindrical body through the adhesive layer to obtain the core of Example 1. The seam Y has a gap of 1mm.

A 1600-m polarizing plate film having a thickness of 148 μm was wound up on the winding core to obtain a raw material roll of the polarizing plate film. Thereafter, the raw material rolls were left to stand for 30 days.

(Example 2)

It was the same as Example 1 except having used the foamed resin layer containing 60 mass % of ethylene/vinyl acetate copolymers as a buffer layer. The 25% compressive stress of the buffer layer is 105kPa.

(comparative example 1)

It was the same as Example 1 except having used the foamed resin layer containing 65 mass % of ethylene/vinyl acetate copolymers as a buffer layer. The 25% compressive stress of the buffer layer is 130kPa.

(comparative example 2)

It was the same as Example 1 except having used the foamed resin layer containing 60 mass % of ethylene/vinyl acetate copolymers as a buffer layer. The 25% compressive stress of the buffer layer is 70kPa.

(comparative example 3)

It was the same as Example 1 except having used the foamed resin layer containing 90 mass % of polyolefins as a buffer layer. The 25% compressive stress of the buffer layer is 34kPa.

(Evaluate)

After being placed, the polarizer film is completely pulled out from the raw material roll. The condition of the surface of the end portion on the inner peripheral side of the film was visually confirmed.

(Due to the depression of the film caused by seam Y)

As shown in FIG. 4 , recesses YY extending linearly in the film F along the axial direction of the core 100 are formed on the film F at approximately constant intervals along the circumferential direction due to the seam Y of the buffer layer 40 . The recess YY is formed over a predetermined length in the circumferential direction from the inner peripheral end to the outer peripheral end of the film F being wound up. The range of the length of the circumferential direction in which the depression YY was formed was confirmed by visual observation for each thin film of an Example and a comparative example. The case where the length is less than 5m is A, the case where the length is more than 5m and less than 10m is B, and the case where the length is more than 10m is C.

(segment marks)

As shown in FIG. 5 , the inner peripheral side end IE of the wound film F is fixed to the laminate 50 (cushion layer) by the double-sided adhesive tape T. The film F wound up on the inner peripheral side end IE will be pushed against the step (angle Q) of the end face of the inner peripheral side end IE, therefore, it will be subjected to the angle Q of the end face, and the film F will form a gap along the roll. A linear trace extending in the axial direction of the core (called step trace QQ). The gap QQ is formed over a predetermined length in the circumferential direction from the inner peripheral side end to the outer peripheral side end of the film F being wound up. The range of the length in the circumferential direction in which the step marks QQ were formed was confirmed by visual observation for each thin film of the examples and the comparative examples. The case where the length is less than 5m is A, the case where the length is more than 5m and less than 10m is B, and the case where the length is more than 10m is C.

(deformation)

The deformation of the film other than dents and step marks was visually observed.

The case where there is no deformation of the film other than dents and step marks is A, the case where the pattern of the buffer layer is transferred to the film is B, and the case where wrinkles are generated on the entire film is C.

The results are shown in the first table.

[first table]

According to the examples, it can be confirmed that the sag of the film caused by the joint between the buffer materials and the step mark of the film caused by the step of the end surface in the longitudinal direction of the film can be reduced, and it is difficult to occur other than that. In addition to the deformation of the film.

10: Cylindrical body

20: Protruding member

22: Large diameter tube part

24: small diameter barrel

30: Adhesive components

40: buffer layer

50: laminated body

100: roll core

Claims (8)

A winding core comprising: a cylindrical body; a buffer layer covering the outer peripheral surface of the cylindrical body; and an adhesive member disposed between the outer peripheral surface of the cylindrical body and the buffer layer; wherein, The 25% compressive stress of the aforementioned buffer layer is 80 to 120kPa; The buffer layer is a foamed resin layer containing 50% by mass or more of an ethylene/vinyl acetate copolymer. The winding core according to claim 1, wherein the buffer layer has a thickness of 0.5 to 3 mm. The winding core according to claim 1 or 2, wherein the adhesive member is a single-layer adhesive layer. The winding core according to claim 1 or 2, wherein the adhesive member has a pair of adhesive layers and a base material layer arranged between the pair of adhesive layers. The core according to claim 3 or 4, wherein the adhesive layer is an acrylic adhesive layer. The winding core according to any one of claims 1 to 5 is used for winding optical films. A raw material roll comprising: the core described in any one of Claims 1 to 6; and an optical film wound on the outer peripheral surface of the core. A method for manufacturing a raw material roll, comprising: a step of winding an optical film on the outer peripheral surface of a core according to any one of Claims 1 to 6.

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