Winding roll

Abstract

To provide a winding roll formed in a roll shape by winding a long belt-like body having flexibility around a winding core, which can be suppressed from being deformed due to stress relaxation caused in the belt-like body.SOLUTION: A winding roll 100 is formed by winding a belt-like body 1, in a circumferential direction of a cylindrical winding core 2, around the winding core 2. An outer peripheral surface of the winding core 2 is provided with adhesion parts 3 for fixing at least a portion of an innermost first periphery part 11 facing an outer peripheral surface of the winding core 2 in the belt-like body 1 to the outer peripheral surface. In the outer peripheral surface of the winding core 2, central angles θ1, θ2, ... corresponding to lengths along the circumferential direction of non-fixed parts 20 of the belt-like body 1 not provided with the adhesion parts 3 are 180° or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a winding roll formed by winding a long, flexible strip around a core. [Background technology]

[0002] Adhesive sheets are widely used in various fields, for example, for bonding two different components together. In recent years, such adhesive sheets have also been used in the manufacture of display devices such as liquid crystal displays (LCDs) and input devices such as touch panels, and the use of adhesive sheets to bond optical components that make up display devices and input devices has enabled the manufacture of various devices with high precision and ease.

[0003] A pressure-sensitive adhesive sheet is a sheet or film-like pressure-sensitive adhesive. During transportation and storage, the pressure-sensitive adhesive sheet is in the form of a laminate in which flexible strip-like release substrates, which are made of a film-like or sheet-like substrate such as a resin or paper substrate coated with a release agent, are bonded to two main surfaces of a long, thin, strip-like pressure-sensitive adhesive sheet, and this laminate sheet is generally wound up around a cylindrical winding core called a core to form a roll.

[0004] As shown in Fig. 9, a portion of the laminate sheet 1 on the side of the starting end 10 where winding around the winding core 2 begins is fixed to the outer circumferential surface of the winding core 2 by an adhesive portion 3 such as double-sided tape. Then, by rotating the winding core 2 in the circumferential direction, the laminate sheet 1 is wound around the winding core 2 so that the first circumferential portion 11, the second circumferential portion 12, the third circumferential portion 13, ... overlap in this order from the inside.

[0005] Here, the first circumferential portion 11 of the laminate sheet 1, which has been wound around the outer circumferential surface of the winding core 2, rides up on the starting end 10, causing the second circumferential portion 12 to overlap the first circumferential portion 11, and as a result of this riding up, deformation D1 due to a step occurs in the first circumferential portion 11 according to the thickness of the laminate sheet 1 and the thickness of the adhesive portion 3. This deformation D1 due to the step occurs each time the laminate sheet 1 is wound up multiple times, and the laminate sheet 1 is formed with deformation D1 due to the step.

[0006] In order to eliminate the occurrence of deformation D1 due to the above-mentioned step, Patent Documents 1 and 2 disclose a technique of providing an elastic resin foam layer on the outer peripheral surface of the winding core 2. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2019-108211 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-199344 Summary of the Invention [Problem to be solved by the invention]

[0008] When laminate sheet 1 is wound around core 2, outer flexible release substrate 5 is stretched and inner flexible release substrate 6 is compressed. As a result, stretch residual stress occurs in outer flexible release substrate 5 of laminate sheet 1, and compressive residual stress occurs in inner flexible release substrate 6. When the wound roll is left in place for a long period of time, such as during storage, particularly in a high-temperature environment in summer, the residual stress described above is relaxed, and outer flexible release substrate 5 shrinks and inner flexible release substrate 6 stretches. As a result, as shown in Figure 9(B) , at first periphery 11 of laminate sheet 1, outer flexible release substrate 5 shrinks, exposing pressure-sensitive adhesive sheet 4 at starting end 10, and inner flexible release substrate 6, which has risen onto starting end 10 as second periphery 12, is attached to the exposed pressure-sensitive adhesive sheet 4. Furthermore, in the first circumferential portion 11 of the laminate sheet 1, the inner flexible release substrate 6 is fixed to the outer peripheral surface of the winding core 2 by the adhesive portion 3 on the starting end 10 side of the laminate sheet 1, and therefore the elongation of the inner flexible release substrate 6 proceeds along the outer peripheral surface of the winding core 2 in the opposite direction to the starting end 10. At this time, the inner flexible release substrate 6 is attached to the exposed adhesive sheet 4 at the starting end 10, and the elongation of the inner flexible release substrate 6 is concentrated in the approximately triangular gap S formed between the first circumferential portion 11 and the outer peripheral surface of the winding core 2 when the first circumferential portion 11 rises onto the starting end 10 as the second circumferential portion 12 just before the starting end 10 of the laminate sheet 1, and therefore slack occurs in the inner flexible release substrate 6 at the position of the gap S. As the inner flexible release substrate 6 slackens, a concave deformation D2 occurs in the adhesive sheet 4 and the outer flexible release substrate 5, and the deformation D2 in the first peripheral portion 11 of the laminate sheet 1 spreads outward, causing deformation D2 due to stress relaxation to form in the second peripheral portion 12 and beyond of the laminate sheet 1.

[0009] The techniques disclosed in the above-mentioned Patent Documents 1 and 2 are effective in suppressing the occurrence of deformation D1 due to steps, but are ineffective in suppressing the occurrence of deformation D2 due to stress relaxation. In addition, if an elastic resin foam layer is provided on the outer peripheral surface of the winding core 2, the effect of resisting deformation due to the winding core 2 is lost, and in fact, this has a negative effect.

[0010] The present invention has been made in consideration of the above-mentioned problems, and aims to suppress deformation due to stress relaxation that occurs in a winding roll formed by winding a long, flexible strip around a winding core. [Means for solving the problem]

[0011] As a result of extensive research to achieve the above-mentioned objective, the inventors discovered that the above-mentioned objective can be achieved by fixing the innermost first circumferential portion of a long, flexible strip to the outer peripheral surface of the winding core at a predetermined position when winding the strip onto the winding core, and thus completed the present invention.

[0012] That is, in order to achieve the above object, the present invention includes a winding roll described in the following item 1.

[0013] Item 1. A winding roll in which a band-shaped body having flexibility in the circumferential direction of a cylindrical winding core is wound around the winding core, an adhesive portion is provided on an outer peripheral surface of the winding core to fix at least a portion of an innermost first peripheral portion of the strip facing the outer peripheral surface of the winding core to the outer peripheral surface; A winding roll, wherein the central angle corresponding to the length along the circumferential direction of the non-fixed portion of the strip-shaped body where the adhesive portion is not provided on the outer peripheral surface of the winding core is 180° or less.

[0014] In the winding roll of the above item 1, the non-fixed portion does not necessarily have to be present on the outer peripheral surface of the winding core, and the winding roll of the above item 1 also includes a configuration in which the adhesive portion is provided around the entire circumferential direction on the outer peripheral surface of the winding core, so that the non-fixed portion does not exist on the outer peripheral surface of the winding core, in other words, the central angle of the non-fixed portion is zero.

[0015] Furthermore, in the winding roll of item 1 above, the central angle of the non-fixed portion being 180° or less means that when there are multiple non-fixed portions on the outer peripheral surface of the winding core, each of the multiple non-fixed portions has a central angle of 180° or less.

[0016] The present invention also encompasses the winding roll described in the following item 2 as a preferred embodiment of the winding roll described in the above item 1.

[0017] Item 2. The winding roll according to Item 1, wherein a plurality of the adhesive portions are provided on the outer peripheral surface of the winding core at intervals in the circumferential direction.

[0018] The present invention also encompasses a winding roll described in the following item 3 or 4 as a preferred embodiment of the winding roll described in the above item 2.

[0019] Item 3. In the strip-shaped body, a portion near the starting end where winding begins on the winding core is fixed to the outer peripheral surface of the winding core by one of the adhesive portions, Item 3. The winding roll according to item 2, wherein the adhesive portion is not interposed between the starting end of the strip and the outer peripheral surface of the winding core.

[0020] Item 4. In the strip-shaped body, a portion including a starting end where winding begins on the winding core is fixed to the outer peripheral surface of the winding core by one of the adhesive portions, the starting end of the strip is fixed to the outer peripheral surface of the winding core by the one adhesive portion between both ends of the one adhesive portion in the circumferential direction, Item 3. The winding roll according to item 2, wherein the first peripheral portion of the strip is fixed to the outer peripheral surface of the winding core by the one adhesive portion at a portion that begins to rise above the starting end of the strip.

[0021] The present invention also encompasses the winding roll described in the following item 5 as a preferred embodiment of the winding roll described in items 1 to 4 above.

[0022] Item 5. The winding roll according to any one of Items 1 to 4, wherein the adhesive portion is a double-sided tape.

[0023] The present invention also encompasses the winding roll described in the following item 6 as a preferred embodiment of the winding roll described in items 1 to 5 above.

[0024] Item 6. The winding roll according to any one of Items 1 to 5, wherein the thickness of the adhesive portion is 30 μm or less.

[0025] The present invention also encompasses the winding roll described in the following item 7 as a preferred embodiment of the winding roll described in items 1 to 6 above.

[0026] Item 7. The winding roll according to any one of Items 1 to 6, wherein the strip has a laminated structure in which flexible release substrates are bonded to two main surfaces of an adhesive sheet. [Effects of the Invention]

[0027] According to the winding roll of the present invention, deformation due to stress relaxation of the strip wound into a roll on the winding core can be suppressed. [Brief explanation of the drawings]

[0028] [Figure 1] 1 shows a schematic configuration of an example of a winding roll according to an embodiment of the present invention. [Figure 2] 10 shows a schematic configuration of another example of a winding roll according to an embodiment of the present invention. [Figure 3] 10 shows a schematic configuration of another example of a winding roll according to an embodiment of the present invention. [Figure 4] 10 shows a schematic configuration of another example of a winding roll according to an embodiment of the present invention. [Figure 5] 2 shows a schematic configuration of a state in which a strip-shaped material has started to be wound around a winding core when manufacturing the winding roll shown in FIG. 1. [Figure 6] 1 shows a schematic cross-sectional configuration of a band-shaped body. [Figure 7] 10 shows a schematic configuration of an example of a winding roll according to another embodiment of the present invention. [Figure 8] 10 shows a schematic configuration of an example of a winding roll according to another embodiment of the present invention. [Figure 9] 1 shows a schematic configuration of a conventional winding roll. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0030] Winding roll 1 to 4 are schematic diagrams of a winding roll 100 according to one embodiment of the present invention. FIG. 5 is a schematic diagram of the state in which winding of a strip 1 around a winding core 2 has begun during the manufacture of the winding roll 100 shown in FIG. 1. The winding roll 100 of this embodiment is formed by winding a long, flexible strip 1 around a winding core 2 in the circumferential direction of the winding core 2 to form a roll. An adhesive section 3 is interposed between the strip 1 and the outer peripheral surface of the winding core 2. A portion of the innermost first peripheral section 11 of the strip 1 facing the outer peripheral surface of the winding core 2 is fixed to the outer peripheral surface of the winding core 2 by a plurality of adhesive sections 3.

[0031] Each component of the take-up roll 100 of this embodiment will be described in more detail below.

[0032] Band The strip 1 has a single-layer structure of a long, thin strip-shaped sheet or film, or a laminate structure of multiple sheets and / or films. The sheet or film is made of a flexible material such as plastic or paper.

[0033] As shown in Figure 5, before being wound around the winding core 2, the strip 1 is long and strip-shaped, and has a width direction and a longitudinal direction that is perpendicular to the width direction and is significantly longer than the width direction. The strip 1 is wound multiple times around the outer circumferential surface of the winding core 2 along the longitudinal direction. The strip 1 has an end 10 on one side in the longitudinal direction and an end (not shown) on the other side in the longitudinal direction. The end 10 on one side of the strip 1 is the starting end from which winding around the winding core 2 begins. Hereinafter, the end 10 on one side of the strip 1 will be referred to as the starting end 10.

[0034] As shown in Figures 1 to 4, when the strip 1 is wound around the winding core 2, it is in the form of a roll in which, from the inside, a first circumferential portion 11, a second circumferential portion 12, a third circumferential portion (not shown), ... are stacked in this order. In the strip 1, the first circumferential portion 11 is the portion that is wound onto the outer circumferential surface of the winding core 2, and the second circumferential portion 12 is the portion that is wound onto the first circumferential portion 11. The n-th circumferential portion (n is an integer of 3 or more) and subsequent portions are the portions that are wound onto the (n-1)-th circumferential portion.

[0035] When the first circumferential portion 11 is wound around the outer peripheral surface of the winding core 2 once, it rides up on the starting end 10 of the strip 1, causing the second circumferential portion 12 to overlap the first circumferential portion 11. In this disclosure, for the sake of convenience, the boundary between the first circumferential portion 11 and the second circumferential portion 12 directly above the starting end 10 of the strip 1 is referred to as the end 110 of the first circumferential portion 11, but the end 110 of the first circumferential portion 11 is not actually clearly indicated on the strip 1. A gap S having a generally triangular cross-section is created between the first circumferential portion 11 of the strip 1 and the outer peripheral surface of the winding core 2 when the first circumferential portion 11 rides up on the starting end 10 of the strip 1 and the second circumferential portion 12 overlaps the first circumferential portion 11.

[0036] As shown in FIG. 6, a specific example of the strip 1 is a laminate comprising a sheet- or film-like adhesive (hereinafter referred to as "adhesive sheet") 4 and a pair of flexible release substrates 5, 6 bonded to the two main surfaces of the adhesive sheet 4. The adhesive sheet 4 is used, for example, to bond two different components together. The two components bonded together by the adhesive sheet 4 are not particularly limited, but an example is bonding optical components that constitute a display device or input device such as a liquid crystal display (LCD) or a touch panel during manufacture. The adhesive sheet 4 is also used, for example, to protect the surface of a panel made of glass, plastic, or the like. The uses of the adhesive sheet 4 are not limited to those described above.

[0037] The pressure-sensitive adhesive sheet 4 is formed, for example, by curing a pressure-sensitive adhesive composition. The pressure-sensitive adhesive composition is not particularly limited, and pressure-sensitive adhesive compositions used in conventionally known pressure-sensitive adhesive sheets can be used. The method for forming the pressure-sensitive adhesive sheet 4 is not particularly limited, and for example, the pressure-sensitive adhesive composition can be applied to one flexible release substrate to form a coating film of the pressure-sensitive adhesive composition, and the coating film can be dried (cured) to form the pressure-sensitive adhesive sheet 4. Another method for forming the pressure-sensitive adhesive sheet 4 is to apply the pressure-sensitive adhesive composition to one flexible release substrate to form a coating film of the pressure-sensitive adhesive composition, then quickly cover the coating film with the other flexible release substrate, and apply ultraviolet light (curing) to the coating film through the flexible release substrate to form the pressure-sensitive adhesive sheet 4. The method for applying the pressure-sensitive adhesive composition to one flexible release substrate is not particularly limited, and conventionally known application methods using commercially available application equipment such as a blade coater, air knife coater, roll coater, bar coater, gravure coater, microgravure coater, rod blade coater, lip coater, die coater, or curtain coater can be used.

[0038] The pair of flexible release substrates 5, 6 have the property (flexibility) of flexibly bending without breaking when wound around the core 2, and are, for example, sheets or films. The material of the pair of flexible release substrates 5, 6 is not particularly limited, and the flexible release substrates 5, 6 can be formed from conventionally known materials such as plastic or paper. Specific examples of the pair of flexible release substrates 5, 6 include release paper made of polyethylene laminated on the surface of paper with a release agent applied thereto, and separator films made of polyester film with a release agent applied thereto. The pair of flexible release substrates 5, 6 may be made of the same material or different materials.

[0039] The substrate with the adhesive sheet may be formed by using a flexible non-release substrate without a release agent coating as one of the pair of flexible release substrates 5, 6. The flexible non-release substrate may be provided with a functional layer such as a mechanical strength-imparting layer or an optical adjustment layer on the back side of the surface to which the adhesive sheet is attached, and a protective substrate may be further laminated to protect the surface to which the functional layer is attached.

[0040] Winding core 1 to 5, the winding core 2 has a cylindrical shape with a predetermined outer diameter and a predetermined length, and in a longitudinal cross section (a cross section perpendicular to the central axis extending in the length direction of the winding core 2), the inner and outer peripheral surfaces both have circular shapes with the same center O. The central axis of the winding core 2 is an imaginary line passing through the center O. There are no particular restrictions on the material of the winding core 2, and the winding core 2 can be made of conventionally known materials such as plastic, paper, resin-containing paper, and metal.

[0041] Adhesive part The adhesive portion 3 is used to fix a portion of the strip 1 to the outer peripheral surface of the winding core 2. The adhesive portion 3 is not particularly limited as long as it tightly adheres the strip 1 to the outer peripheral surface of the winding core 2 so that they do not easily separate. For example, the adhesive portion 3 can be formed using double-sided tape, an adhesive, a pressure-sensitive adhesive, etc. Among these, from the viewpoints of improving work efficiency (work time, work man-hours) and dimensional accuracy (width accuracy, thickness accuracy), it is preferable to form the adhesive portion 3 using double-sided tape. The adhesive portion 3 is formed, for example, in advance on the outer peripheral surface of the winding core 2. As shown in FIGS. 1 to 4 , when the strip 1 is wound onto the winding core 2, a portion of the innermost first circumferential portion 11 facing the outer peripheral surface of the winding core 2 is fixed to the outer peripheral surface of the winding core 2 by multiple adhesive portions 3.

[0042] As shown in Figure 5, the adhesive portion 3 has a pair of side edges 30, 31 that face each other with a gap in the circumferential direction of the winding core 2, and a pair of end edges 32, 33 that face each other with a gap in the longitudinal direction of the winding core 2. The length L1 of the pair of side edges 30, 31 of the adhesive portion 3 (the length of the adhesive portion 3 along the width direction of the strip 1, hereinafter referred to as the "width of the adhesive portion 3") is not particularly limited, but is preferably the same as or greater than the width direction length of the strip 1. The length L2 of the pair of end edges 32, 33 of the adhesive portion 3 (a predetermined length along the circumferential direction of the winding core 2, hereinafter referred to as the "length of the adhesive portion 3") is equal to or less than the circumferential length of the outer surface of the winding core 2.

[0043] As shown in FIG. 1 , the adhesive portion 3 has a predetermined thickness T. While not particularly limited, the thickness T of the adhesive portion 3 is preferably 30 μm or less, and more preferably 15 μm or less. When the first circumferential portion 11 of the strip 1 is wound around the outer peripheral surface of the winding core 2 and reaches the starting end 10 of the strip 1, it must overcome a step corresponding to the thickness of the strip 1 and the thickness T of the adhesive portion 3. By setting the thickness T of the adhesive portion 3 to 30 μm or less, the step can be reduced, thereby minimizing the deformation D1 that occurs in the strip 1 due to this step. Although not particularly limited, the thickness T of the adhesive portion 3 is preferably 4 μm or more.

[0044] Although there are no particular limitations on the number of adhesive portions 3, as shown in Figures 1 to 4, it is preferable that a plurality of adhesive portions 3 are provided on the outer peripheral surface of the winding core 2, with the plurality of adhesive portions 3 being spaced apart in the circumferential direction on the outer peripheral surface of the winding core 2. As a result, the outer peripheral surface of the winding core 2 has, along the circumferential direction, a plurality of adhesive portions 3 that secure the strip 1 to the outer peripheral surface and a plurality of non-secured portions 20 that do not secure the strip 1 to the outer peripheral surface. When a plurality of adhesive portions 3 are provided on the outer peripheral surface of the winding core 2, there are no particular limitations on the length L2 of the adhesive portions 3, but in order to neatly wind the strip 1 around the winding core 2 while preventing wrinkles and the like, the length L2 of the adhesive portions 3 is preferably 5 mm to 100 mm, more preferably 10 mm to 50 mm, and most preferably 12 mm to 25 mm.

[0045] In the winding roll 100 shown in FIGS. 1 and 2, two bonded portions 3 are provided at intervals in the circumferential direction on the outer peripheral surface of the winding core 2, with two bonded portions 3 and two non-fixed portions 20 alternating on the outer peripheral surface of the winding core 2. In the winding roll 100 shown in FIG. 3, three bonded portions 3 are provided at intervals in the circumferential direction on the outer peripheral surface of the winding core 2, with three bonded portions 3 and three non-fixed portions 20 alternating on the outer peripheral surface of the winding core 2. In the winding roll 100 shown in FIG. 4, four bonded portions 3 are provided at intervals in the circumferential direction on the outer peripheral surface of the winding core 2, with four bonded portions 3 and four non-fixed portions 20 alternating on the outer peripheral surface of the winding core 2. Five or more bonded portions 3 may be provided at intervals in the circumferential direction on the outer peripheral surface of the winding core 2.

[0046] The presence of the non-fixed portions 20 on the outer peripheral surface of the winding core 2 allows the strip 1 to be neatly wound around the winding core 2 while preventing wrinkles and the like. In addition, the non-fixed portions 20 occupy a wide range in the circumferential direction of the outer peripheral surface of the winding core 2, allowing the strip 1 to be wound around the winding core 2 more neatly.

[0047] One of the multiple adhesive portions 3 is not particularly limited, but it is preferable to fix a portion of the strip 1 on the side of the starting end 10 to the outer peripheral surface of the winding core 2, as shown in Figures 1 to 4. This makes it easier to wind the strip 1 onto the winding core 2. The portion of the strip 1 on the side of the starting end 10 may be a portion including the starting end 10 (a portion within a predetermined length from the starting end 10), as shown in Figures 1, 3, and 4, or a portion close to the starting end 10 (a portion within a predetermined length from a position, for example, 10 mm to 130 mm away from the starting end 10), as shown in Figure 2.

[0048] Although there are no particular limitations on the starting end 10 of the strip 1, it is preferable that, as shown in Figure 2, it is not aligned with one end (side edge 31 in Figure 5) of the adhesive part 3 that fixes a portion of the strip 1 on the starting end 10 side to the outer peripheral surface of the winding core 2. In other words, it is preferable that the starting end 10 of the strip 1 is not positioned on the adhesive part 3 but protrudes circumferentially from the adhesive part 3, so that the adhesive part 3 is not interposed between the starting end 10 and the outer peripheral surface of the winding core 2, and the strip 1 is not fixed to the outer peripheral surface of the winding core 2 by the adhesive part 3.

[0049] In the winding roll 100 shown in Figures 1, 3 and 4, when the first peripheral portion 11 of the strip 1 is wound around the outer peripheral surface of the winding core 2 once and rides over the starting end 10 of the strip 1, it rides over a step corresponding to the thickness of the strip 1 and the thickness T of the adhesive portion 3 in one go.

[0050] In contrast, in the winding roll 100 shown in Figure 2, the starting end 10 of the strip 1 is not located on the adhesive portion 3 but is in contact with the outer peripheral surface of the winding core 2. Therefore, when the first peripheral portion 11 of the strip 1 is wound around the outer peripheral surface of the winding core 2 once and rides over the starting end 10 of the strip 1, it only needs to overcome a step corresponding to the thickness of the strip 1. Therefore, in the winding roll 100 shown in Figure 2, the deformation D1 caused in the strip 1 by the step described above can be reduced. Furthermore, in the winding roll 100 shown in Figure 2, the starting end 10 of the strip 1 is not fixed to the outer peripheral surface of the winding core 2, so the step marks caused in the strip 1 can be reduced.

[0051] 3 and 4, the position of the starting end 10 of the strip 1 relative to the adhesive portion 3 can be changed in the same way as in the winding roll 100 shown in FIG.

[0052] At least one remaining adhesive portion 3 of the multiple adhesive portions 3 is provided on the outer peripheral surface of the winding core 2 so that, for each of the multiple non-fixed portions 20 on the outer peripheral surface of the winding core 2, the central angle θ1, θ2, ... corresponding to the length along the circumferential direction of the winding core 2 is 180° or less. In other words, for each of the multiple non-fixed portions 20 on the outer peripheral surface of the winding core 2, the angle (∠E1OE2) formed by connecting the boundary E1 with one adjacent adhesive portion 3 and the boundary E2 with another adjacent adhesive portion 3 in a vertical cross-sectional view with the center O of the winding core 2 is 180° or less.

[0053] As a result, as shown in Figures 1 to 4, the first peripheral portion 11 of the strip 1 wound around the outer peripheral surface of the winding core 2 is fixed to the outer peripheral surface of the winding core 2 by multiple adhesive portions 3 at intervals of approximately 180° or less in the circumferential direction of the winding core 2.

[0054] When strip 1 is wound around core 2, outer flexible release substrate 5 is stretched and inner flexible release substrate 6 is compressed. As a result, stretch residual stress occurs in outer flexible release substrate 5 of strip 1, and compressive residual stress occurs in inner flexible release substrate 6. When the wound roll is left in place for a long period of time, such as during storage, particularly in a high-temperature environment in summer, the residual stress described above is relaxed, causing outer flexible release substrate 5 to shrink and inner flexible release substrate 6 to stretch. As a result, at first peripheral portion 11 of strip 1, outer flexible release substrate 5 shrinks, exposing pressure-sensitive adhesive sheet 4 at starting end 10, and inner flexible release substrate 6, which has risen onto starting end 10 as second peripheral portion 12, adheres to the exposed pressure-sensitive adhesive sheet 4. Furthermore, in the first circumferential portion 11 of the laminate sheet 1, the inner flexible release substrate 6 is fixed to the outer peripheral surface of the winding core 2 by the adhesive portion 3 on the starting end 10 side of the laminate sheet 1, and therefore the inner flexible release substrate 6 elongates along the outer peripheral surface of the winding core 2 in the opposite direction to the starting end 10. Here, if the first circumferential portion 11 of the strip 1 is not fixed to the outer peripheral surface of the winding core 2 at any part other than the part on the starting end 10 side of the strip 1, the elongation of the inner flexible release substrate 6 will be concentrated in the approximately triangular gap S formed between the first circumferential portion 11 and the outer peripheral surface of the winding core 2 when the first circumferential portion 11 rides over the starting end 10 as the second circumferential portion 12 just before the starting end 10 of the strip 1. Therefore, as shown in Figure 9, in the prior art, the inner flexible release substrate 6 sags significantly at the position of the gap S, and this sagging causes a concave deformation D2 in the pressure-sensitive adhesive sheet 4 and the outer flexible release substrate 5. This deformation D2 of the first circumferential portion 11 of the band-shaped body 1 spreads outward, and deformation D2 due to stress relaxation is formed in the second circumferential portion 12 and beyond of the band-shaped body 1.

[0055] 1 to 4, if the first circumferential portion 11 of the strip 1 is fixed to the outer peripheral surface of the winding core 2 by the adhesive portion 3 not only at a portion on the starting end 10 side of the strip 1 but also at one or more other portions, the elongation of the inner flexible release substrate 6 due to stress relaxation is absorbed by the adhesive portion 3 each time and is not concentrated in the gap S. Therefore, slackening of the inner flexible release substrate 6 at the position of the gap S is suppressed, and therefore the winding roll 100 of this embodiment can suppress deformation D2 due to stress relaxation from occurring at the first circumferential portion 11, the second circumferential portion 12, and beyond.

[0056] In this way, the presence of multiple adhesive sections 3 on the outer peripheral surface of the winding core 2 at intervals of approximately 180° or less in the circumferential direction of the winding core 2 can prevent deformation D2 due to stress relaxation from occurring in the strip 1 wound around the winding core 2. Furthermore, the presence of many adhesive sections 3 in the circumferential direction of the outer peripheral surface of the winding core 2 can more effectively prevent deformation D2 due to stress relaxation from occurring in the strip 1.

[0057] The central angles θ1, θ2, ... of the multiple non-fixed portions 20 may be the same size or different sizes from each other, or may be the same size for some and different sizes for others, and are not particularly limited as long as they are 180° or less.

[0058] Effects of the winding roll The winding roll 100 of the present embodiment described above is characterized in that an adhesive section 3 is provided on the outer peripheral surface of the winding core 2 for fixing at least a portion of the first peripheral portion 11 of the strip 1 to the outer peripheral surface, and the central angle θ1, θ2,... of the non-fixed portion 20 of the strip 1 where the adhesive section 3 is not provided on the outer peripheral surface of the winding core 2 is 180° or less. This feature, as described above, relieves the compressive residual stress inherent in the flexible release substrate 6 on the inner side of the strip 1. Even if the inner flexible release substrate 6 elongates due to stress relaxation, this elongation is absorbed by the adhesive section 3 and does not concentrate in the approximately triangular gap S formed between the first peripheral portion 11 of the strip 1 and the outer peripheral surface of the winding core 2. Therefore, loosening of the inner flexible release substrate 6 at the gap S is suppressed, thereby suppressing deformation D2 due to stress relaxation from occurring in the first peripheral portion 11, second peripheral portion 12, and subsequent portions of the strip 1.

[0059] The winding roll 100 of the present embodiment described above can be characterized by being configured such that a plurality of bonded sections 3 are provided on the outer peripheral surface of the winding core 2 at intervals in the circumferential direction of the winding core 2. Due to this feature, as described above, the winding roll 100 has a plurality of bonded sections 3 and a plurality of non-fixed sections 20 along the circumferential direction on the outer peripheral surface of the winding core 2. The presence of the non-fixed sections 20 on the outer peripheral surface of the winding core 2 allows the strip 1 to be neatly wound around the winding core 2 while suppressing the occurrence of wrinkles and the like.

[0060] The winding roll 100 of the present embodiment described above can be characterized in that a portion of the strip 1 near the starting end 10 is fixed to the outer peripheral surface of the winding core 2 by one of the multiple adhesive portions 3, and the starting end 10 of the strip 1 is not fixed to the outer peripheral surface of the winding core 2 by the adhesive portion 3. This feature allows the winding roll 100 to easily wind the strip 1 onto the winding core 2, as described above. Furthermore, when the first peripheral portion 11 of the strip 1 is wound around the outer peripheral surface of the winding core 2 once and rides over the starting end 10 of the strip 1, it only needs to overcome a step corresponding to the thickness of the strip 1. This makes it possible to reduce deformation D1 of the strip 1 caused by the step.

[0061] Winding roll of another embodiment Although one embodiment of the present invention has been described above, the above-described embodiment is merely one of various embodiments of the present invention, and the present invention is not limited to the above-described embodiment. Various modifications of the embodiment of the present invention are possible without departing from the spirit of the present invention. Other embodiments of the present invention will be described below. The objects of the present invention can also be achieved in the other embodiments described below.

[0062] For example, Fig. 7 is a schematic diagram of a take-up roll 100 according to another embodiment of the present invention. In the take-up roll 100 shown in Fig. 7, the adhesive portion 3 that fixes a portion of the starting end 10 side of the strip 1 to the outer peripheral surface of the winding core 2 has one end (side edge 31 in Fig. 5) of the adhesive portion 3 that protrudes circumferentially beyond the strip 1, and the starting end 10 of the strip 1 is fixed to the outer peripheral surface of the winding core 2 by the adhesive portion 3 between both ends of the adhesive portion 3 (side edges 30, 31 in Fig. 5).

[0063] The adhesive portion 3, which fixes a portion of the strip 1 on the starting end 10 side to the outer peripheral surface of the winding core 2, also fixes a portion 111 of the first circumferential portion 11 of the strip 1 that begins to ride up onto the starting end 10 (hereinafter referred to as the "starting portion of the first circumferential portion 11") to the outer peripheral surface of the winding core 2. The starting portion 111 of the first circumferential portion 11 is a portion close to the end 110 of the first circumferential portion 11 that has ride up onto the starting end 10 of the strip 1, and is a portion that is separated from the outer peripheral surface of the winding core 2 before the starting end 10 because the first circumferential portion 11 rides up onto the starting end 10 as the second circumferential portion 12.

[0064] In the winding roll 100 shown in FIG. 7, the starting end 10 of the strip 1 is located between both ends of the adhesive portion 3 (side edges 30, 31 in FIG. 5), and one end of the adhesive portion 3 (side edge 31 in FIG. 5) protrudes circumferentially beyond the strip 1. This one end of the adhesive portion 3 (side edge 31 in FIG. 5) extends to the start of the ride-on portion 111 of the first peripheral portion 11 of the strip 1, thereby fixing the start of the ride-on portion 111 to the outer peripheral surface of the winding core 2 by the adhesive portion 3. As a result, the elongation of the inner flexible release substrate 6 due to stress relaxation is absorbed by the adhesive portion 3 and does not significantly affect the gap S. Therefore, the inner flexible release substrate 6 is effectively prevented from loosening at the gap S, which more effectively prevents deformation D2 due to stress relaxation in the strip 1. Furthermore, if one end of the adhesive portion 3 (side edge 31 in Figure 5) extends to the initial portion 111 of the first circumferential portion 11 of the strip 1 at which the first circumferential portion 11 begins to ride over the starting end 10 as the second circumferential portion 12, that is, to the portion where the first circumferential portion 11 of the strip 1 begins to move away from the outer surface of the winding core 2, the occurrence of deformation D2 in the strip 1 due to stress relaxation can be more effectively suppressed.

[0065] 7, the start end 10 of the strip 1 is located between the pair of side edges 30, 31 of the adhesive portion 3. Therefore, when the first peripheral portion 11 of the strip 1 is wound around the outer peripheral surface of the winding core 2 and rides on the start end 10 of the strip 1, it only needs to ride over a step corresponding to the thickness T of the adhesive portion 3 and a step corresponding to the thickness of the strip 1 minus the thickness T of the adhesive portion 3 in sequence, and does not ride over the steps corresponding to the thicknesses of the strip 1 and the thickness T of the adhesive portion 3 all at once. Therefore, the take-up roll 100 shown in FIG. 7 can reduce the deformation D1 of the strip 1 caused by the step described above, compared to the conventional take-up roll shown in FIG. 9.

[0066] 3 and 4, the position of the starting end 10 of the strip 1 relative to the adhesive portion 3 can be changed in the same way as in the winding roll 100 shown in FIG.

[0067] FIG. 8 is a schematic diagram of a take-up roll 100 according to another embodiment of the present invention. In all of the take-up rolls 100 described above, multiple bonded portions 3 are provided at intervals on the outer circumferential surface of the winding core 2. However, as in the take-up roll 100 shown in FIG. 8, only one bonded portion 3 may be provided on the outer circumferential surface of the winding core 2. When only one bonded portion 3 is provided on the outer circumferential surface of the winding core 2, as shown in FIG. 8, the bonded portion 3 may be provided along the entire circumferential direction on the outer circumferential surface of the winding core 2. In other words, the length of the bonded portion 3 may be the same as the circumferential length of the outer circumferential surface of the winding core 2. In this case, there is no unfixed portion 20 on the outer circumferential surface of the winding core 2 (the central angle θ of the unfixed portion 20 is zero), and almost the entire innermost first circumferential portion 11 of the strip 1 facing the outer circumferential surface of the winding core 2 is fixed to the outer circumferential surface of the winding core 2 by a single bonded portion 3.

[0068] Alternatively, although not shown, the adhesive portion 3 may be provided over a portion of the circumferential direction on the outer circumferential surface of the winding core 2; in other words, the length of the adhesive portion 3 may be shorter than the circumferential length of the outer circumferential surface of the winding core 2. In this case, one adhesive portion 3 and one non-fixed portion 20 are present on the outer circumferential surface of the winding core 2, and a portion of the innermost first circumferential portion 11 of the strip 1 facing the outer circumferential surface of the winding core 2 is fixed to the outer circumferential surface of the winding core 2 by one adhesive portion 3. The length L of the adhesive portion 3 is set so that the central angle θ of the non-fixed portion 20 is 180° or less. In addition, it is preferable that the adhesive portion 3 fix a portion of the strip 1 on the starting end 10 side to the outer circumferential surface of the winding core.

[0069] Furthermore, in all of the above-described embodiments of the take-up roll 100, the strip 1 has a laminated structure including the adhesive sheet 4. However, in other embodiments of the take-up roll, the strip 1 may have a single-layer structure or a multi-layer structure without the adhesive sheet 4. Even if the strip 1 does not have the adhesive sheet 4, when the strip 1 is wound around the winding core 2 under tension, the elongation of the inner flexible release substrate 6 due to stress relaxation is concentrated to a considerable extent in the approximately triangular gap S formed between the strip 1 and the outer peripheral surface of the winding core 2 when the first circumferential portion 11 rises onto the starting end 10 as the second circumferential portion 12 just before the starting end 10 of the strip 1. Therefore, even when the strip 1 does not have the adhesive sheet 4, the application of the present invention can prevent deformation D2 due to stress relaxation from occurring in the strip 1. [Example]

[0070] The following examples of the winding roll of the present invention will be used to specifically explain the action and effect, but the winding roll of the present invention is not limited to the following examples.

[0071] In both Examples 1-6 and Comparative Example 1, the strips were laminate sheets prepared by laminating a 150 μm thick adhesive sheet on the release surface of a 100 μm thick PET-based flexible release substrate, and then laminating another 75 μm thick PET-based flexible release substrate on the adhesive sheet so that its release surface was in contact with the adhesive sheet. The strips had a width of 1,400 mm. The strips were wound around a 1,450 mm wide, 6-inch resin core using a winding device with an automatic frame changer, with different methods of fastening the first periphery of the strip to the outer periphery of the core.

[0072] In Example 1, as in the winding roll shown in Figure 8, spray glue was applied to the entire outer surface of the winding core, and the strip was wound around the winding core while the first circumferential portion was fixed entirely to the outer surface of the winding core.

[0073] In Example 2, as in the winding roll shown in Figure 1, two double-sided tapes, first and second, each 15 µm thick and 24 mm long (shown in Figure 5), were attached to the outer peripheral surface of the winding core at equally spaced positions (positions facing each other on the outer peripheral surface of the winding core) parallel to the central axis of the winding core over the entire length of the winding core, and the starting end of the strip was positioned on the first double-sided tape and aligned with the end of the first double-sided tape, and the strip was wound around the winding core.

[0074] In Example 3, as in the winding roll shown in Figure 3, three double-sided tapes, namely, first, second, and third double-sided tapes, each 15 µm thick and 24 mm long (shown in Figure 5), were attached to the outer peripheral surface of the winding core at equally spaced positions along the entire length of the winding core, parallel to the central axis of the winding core, and the strip was wound around the winding core with the starting end of the strip positioned on the first double-sided tape and aligned with the end of the first double-sided tape.

[0075] In Example 4, as in the winding roll shown in Figure 4, four double-sided tapes, namely first, second, third and fourth tapes, each 15 µm thick and 24 mm long (shown in Figure 5), were attached to the outer peripheral surface of the winding core at equally spaced positions along the entire length of the winding core, parallel to the central axis of the winding core, and the strip was wound around the winding core with the starting end of the strip positioned on the first double-sided tape and aligned with the end of the first double-sided tape.

[0076] In Example 5, as in the winding roll shown in Figure 2, two double-sided tapes, first and second, each 15 µm thick and 12 mm long (shown in Figure 5), were attached to the outer peripheral surface of the winding core at equally spaced positions (opposite positions on the outer peripheral surface of the winding core) parallel to the central axis of the winding core over the entire length of the winding core, and the strip was wound around the winding core so that the starting end of the strip was not positioned on the first double-sided tape but protruded from the first double-sided tape by approximately 100 mm in the circumferential direction of the winding core.

[0077] In Example 6, as in the winding roll shown in Figure 7, two double-sided tapes, first and second, each 15 µm thick and 24 mm long (shown in Figure 5), were attached to the outer peripheral surface of the winding core at equally spaced positions (positions facing each other on the outer peripheral surface of the winding core) along the entire length of the winding core, parallel to the central axis of the winding core, and the strip was wound around the winding core so that the starting end of the strip was positioned near the center in the direction of the length L2 of the first double-sided tape.

[0078] In Comparative Example 1, as in the conventional winding roll shown in Figure 9, double-sided tape having a thickness of 15 μm and a length L2 (shown in Figure 5) of 12 mm was attached along the entire length of the winding core parallel to the central axis of the winding core, and the strip was wound around the winding core with the starting end of the strip positioned on the double-sided tape and aligned with the end of the double-sided tape.

[0079] The wound rolls of Examples 1-6 and Comparative Example 1 were left to stand for 4 days in a thermostatic chamber at 40°C, and the wound lengths from the start of winding at which the rolls were judged to be unusable due to transfer of deformation around the core were compared.

[0080] In Example 1, the first circumferential portion of the strip was fixed to the outer peripheral surface of the winding core with double-sided tape at the point where it began to climb over the starting end of the strip. In Example 1, wrinkles occurred when the first circumferential portion was wound around the outer peripheral surface of the winding core, but deformation D2 due to stress relaxation did not occur. Therefore, deformation transfer in Example 1 was limited to 18 m from the start of winding.

[0081] In Example 2, deformation D1 occurred due to a step when the first circumferential portion of the strip rode over the starting end of the strip, but deformation D2 due to stress relaxation was suppressed. Therefore, deformation transfer in Example 2 was suppressed to 18 m from the start of winding.

[0082] In Example 3, deformation D1 occurred due to a step when the first circumferential portion of the strip rode over the starting end of the strip, but deformation D2 due to stress relaxation was suppressed. Therefore, deformation transfer in Example 3 was suppressed to 16 m from the start of winding.

[0083] In Example 4, deformation D1 occurred due to a step when the first circumferential portion of the strip rode over the starting end of the strip, but deformation D2 due to stress relaxation was suppressed. Therefore, deformation transfer in Example 4 was suppressed to 16 m from the start of winding.

[0084] In Example 5, deformation D1 occurred due to a step when the first circumferential portion of the strip rode over the starting edge of the strip. However, deformation D1 was reduced because the magnitude of deformation D1 corresponded only to the thickness of the strip, 325 μm. In addition, deformation D2 due to stress relaxation was suppressed. Therefore, deformation transfer in Example 5 was suppressed to 14 m from the start of winding.

[0085] In Example 6, the first circumferential portion of the strip was fixed to the outer peripheral surface of the winding core with a first double-sided tape at the point where it began to climb up onto the starting end of the strip. In Example 6, the first circumferential portion of the strip climbed up onto the 15 μm-thick first double-sided tape before climbing up onto the starting end of the strip. The deformation D1 caused by the step when the first circumferential portion of the strip climbed up onto the starting end of the strip was mainly of a size corresponding to the 325 μm thickness of the strip, and deformation D1 was reduced. In addition, deformation D2 due to stress relaxation did not occur. Therefore, deformation transfer in Example 6 was limited to 14 m from the start of winding.

[0086] In Comparative Example 1, when the first circumferential portion of the strip reached the start of the strip, it also reached the double-sided tape at once, so that deformation D1 caused by the step when the first circumferential portion of the strip reached the start of the strip was a size corresponding to the thickness of the strip (325 μm) plus the thickness of the double-sided tape (15 μm), and deformation D2 due to stress relaxation occurred before and after the start of the strip. Therefore, deformation transfer in Comparative Example 1 extended for 20 m from the start of winding.

[0087] From the above, it was confirmed that the winding roll of the present invention can suppress deformation of the strip wound around the winding core. [Explanation of symbols]

[0088] 1. Band 2 Winding cores 3 Adhesive part 10 Beginning of the band 11 First circumference of the band 20 Unfixed portion on the outer surface of the winding core 100 winding rolls 111 The part that starts riding on the beginning of the strip

Claims

1. A winding roll in which a band-shaped body having flexibility in the circumferential direction of a cylindrical winding core is wound around the winding core, the strip-shaped body has a laminated structure in which flexible release substrates are bonded to two main surfaces of a pressure-sensitive adhesive sheet, an adhesive portion is provided on an outer peripheral surface of the winding core to fix at least a portion of an innermost first peripheral portion of the strip facing the outer peripheral surface of the winding core to the outer peripheral surface; On the outer peripheral surface of the winding core, a central angle corresponding to the length along the circumferential direction of each of the non-fixed portions of the band-shaped body where the adhesive portion is not provided is 180° or less, The adhesive part is a double-sided tape, The thickness of the adhesive portion is 30 μm or less.

2. A winding roll as described in claim 1, wherein the thickness of the adhesive portion is 15 μm or less.

3. A winding roll as described in claim 1 or 2, wherein the thickness of the adhesive portion is 4 μm or more.

4. The winding roll according to claim 1 or 2, wherein a plurality of the adhesive portions are provided on the outer peripheral surface of the winding core at intervals in the circumferential direction.

5. a portion of the strip near a starting end where winding on the winding core begins is fixed to the outer peripheral surface of the winding core by one of the adhesive portions, The winding roll according to claim 4 , wherein the adhesive portion is not interposed between the starting end of the strip and the outer circumferential surface of the winding core.

6. a portion of the strip including a starting end where winding is to begin around the winding core is fixed to the outer peripheral surface of the winding core by one of the adhesive portions, the starting end of the strip is fixed to the outer peripheral surface of the winding core by the one adhesive portion between both ends of the one adhesive portion in the circumferential direction, The winding roll according to claim 4 , wherein a portion of the first circumferential portion of the strip that begins to rise above the starting end of the strip is fixed to the outer peripheral surface of the winding core by the one adhesive portion.

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