Adhesive sheet, tacky sheet, and exterior sheet

Abstract

To provide an adhesive sheet, a tacky sheet, and an exterior sheet, capable of improving adaptability to curved surfaces.SOLUTION: An adhesive sheet AS includes an adhesive layer AD and a substrate BS supporting the adhesive layer AD, the substrate BS having an auxetic structure. A tacky sheet PS includes a tacky layer PD and a substrate BS supporting the tacky layer PD, the substrate BS having an auxetic structure. An exterior sheet ES includes a surface layer BS including one surface BS1 of the exterior sheet ES, the surface layer BS having an auxetic structure.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an adhesive sheet, a pressure-sensitive adhesive sheet, and an exterior sheet. [Background technology]

[0002] 2. Description of the Related Art Sheets having irregularities formed on their surfaces are known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-48238 A Summary of the Invention [Problem to be solved by the invention]

[0004] The uneven sheet-like object (sheet) described in Patent Document 1 is a general sheet having a positive Poisson's ratio, so when the sheet is bent, as shown in Fig. 8, a tension or compression force due to bending acts in one direction, while a force in the opposite direction acts in the perpendicular direction, causing the sheet to warp in the opposite direction to the bending direction. Therefore, there is a disadvantage that the sheet is not sufficiently able to follow the curved surface.

[0005] An object of the present invention is to provide an adhesive sheet, a pressure-sensitive adhesive sheet, and an exterior sheet that can improve the ability to conform to a curved surface. [Means for solving the problem]

[0006] An adhesive sheet according to one embodiment of the present invention comprises an adhesive layer and a substrate supporting the adhesive layer, the substrate having an auxetic structure.

[0007] A pressure-sensitive adhesive sheet according to one embodiment of the present invention comprises a pressure-sensitive adhesive layer and a substrate supporting the pressure-sensitive adhesive layer, the substrate having an auxetic structure.

[0008] In the adhesive sheet or pressure-sensitive adhesive sheet according to one embodiment of the present invention, the auxetic structure may be constituted by irregularities formed on the substrate.

[0009] In an adhesive sheet or pressure-sensitive adhesive sheet according to one embodiment of the present invention, the auxetic structure may be constituted by a cutout formed in the substrate.

[0010] An exterior sheet according to one embodiment of the present invention comprises a surface layer including one surface of the exterior sheet, the surface layer having an auxetic structure.

[0011] In the exterior sheet according to one aspect of the present invention, the auxetic structure may be constituted by irregularities formed on the surface layer.

[0012] In an exterior sheet according to one aspect of the present invention, the auxetic structure may be formed by cutouts formed in the surface layer. Effect of the Invention

[0013] According to the present invention, since the substrate of the adhesive or pressure-sensitive adhesive sheet or the surface layer of the exterior sheet has an auxetic structure, when the sheet is bent in one direction to apply tension or compression to the substrate or surface layer, tension or compression is also applied to the substrate or surface layer in the perpendicular direction, thereby improving the curved surface conformability of the sheet. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is an explanatory diagram of a seat according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the sheet of FIG. 1 taken along line II-II. [Diagram 3] FIG. [Figure 4] FIG. 11 is an explanatory diagram of a seat according to a modified example of the present invention. [Diagram 5] FIG. 11 is an explanatory diagram of a seat according to a modified example of the present invention. [Figure 6]FIG. 11 is an explanatory diagram of a seat according to a modified example of the present invention. [Figure 7] FIG. 11 is an explanatory diagram of a seat according to a modified example of the present invention. [Figure 8] 11A to 11C are diagrams showing examples of defects in a conventional sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the X-axis, Y-axis, and Z-axis are mutually orthogonal, the X-axis and Y-axis are axes within a specified plane, and the Z-axis is an axis orthogonal to the specified plane. Furthermore, in this embodiment, when indicating directions, "up" is the direction of the Z-axis arrow, "down" is the opposite direction, "left" is the direction of the X-axis arrow, "right" is the opposite direction, "front" is the direction of the Y-axis arrow, and "back" is the opposite direction.

[0016] 1 and 2, the adhesive sheet AS comprises an adhesive layer AD and a substrate BS supporting the adhesive layer AD, and the substrate BS has an auxetic structure. Note that an auxetic structure is a structure that has a negative Poisson's ratio, i.e., a structure that exerts a negative Poisson's effect.

[0017] The adhesive layer AD is composed of any adhesive material depending on the application of the adhesive sheet AS and the type and material of the substrate BS, such as an acrylic adhesive, a rubber adhesive, a silicone adhesive, a polyurethane adhesive, a polyester adhesive, an epoxy adhesive, and a polyimide adhesive, and has a thickness of 1 μm to 2 mm.

[0018] The substrate BS may be made of any material, such as paper, laminated paper, plastic, cellulose, rubber, etc., depending on the application of the adhesive sheet AS and the type and material of the adhesive layer AD, and may have a thickness of 10 μm to 2 mm. Examples of the paper include kraft paper, fine paper, glassine paper, impregnated paper, coated paper, etc., and examples of the laminated paper include paper laminated with a thermoplastic resin such as polyethylene. Examples of the plastic include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene, polymethylpentene, and polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polystyrene, polycarbonate, polyvinyl alcohol, polyurethane, and acrylic resins. Examples of the cellulose include cellulose triacetate, cellulose diacetate, and cellophane, and examples of the rubber include natural rubber and synthetic rubber. The substrate BS may be a single layer, or may be a multilayer of two or more layers of the same or different types.

[0019] Here, the substrate BS has an unevenness formed of convex portions CV and concave portions DN on its non-adhesive surface BS1 (the surface opposite to the adhesive surface AD1 of the adhesive sheet AS), and the unevenness constitutes an auxetic structure. Such a substrate BS is formed, for example, by embossing the substrate BS before the unevenness is formed. Note that the thickness of the uneven layer in this embodiment, i.e., the height of the convex portions CV and the depth of the concave portions DN, is 30% or more of the thickness of the adhesive sheet AS.

[0020] The protrusions CV are composed of a first protrusion CV1 and a second protrusion CV2 each extending in the left-right direction as a first direction, and a third protrusion CV3 and a fourth protrusion CV4 each extending in the front-rear direction as a second direction perpendicular to the first direction. The protrusions CV are formed such that in a region where the distance between the first protrusion CV1 and the second protrusion CV2 is wide, the distance between the third protrusion CV3 and the fourth protrusion CV4 is narrow, and in a region where the distance between the first protrusion CV1 and the second protrusion CV2 is narrow, the distance between the third protrusion CV3 and the fourth protrusion CV4 is wide. The area ratio of the protrusions CV to the non-bonding surface BS1 of the substrate BS is 30% or less. The first protrusions CV1 are formed in a generally sinusoidal shape extending in the left-right direction, and a plurality of the first protrusions CV1 are arranged side by side in the front-rear direction. The second protrusions CV2 are formed into a generally sinusoidal shape with a phase shift of 180 degrees from that of the first protrusions CV1, and a plurality of second protrusions CV2 are arranged in parallel in the front-rear direction so as to be alternately arranged with the first protrusions CV1. The third convex portion CV3 has a generally sinusoidal shape extending in the front-to-rear direction in the same shape as the first convex portion CV1, and multiple third convex portions CV3 are arranged side by side in the left-to-right direction and intersect with the first convex portion CV1 and the second convex portion CV2. The fourth convex portion CV4 has an approximately sinusoidal shape with the phase of the third convex portion CV3 shifted by 180 degrees, and multiple fourth convex portions CV4 are arranged side by side in the left-right direction so as to be alternated with the third convex portion CV3, and intersect with the first convex portion CV1 and the second convex portion CV2.

[0021] The recess DN is formed in a region surrounded by the first to fourth convex portions CV1 to CV4 and is partitioned by these convex portions CV1 to CV4. The recess DN includes a first recess DN1 and a second recess DN2 having the same shape as the first recess DN1 but oriented in a different direction. The first recess DN1 is formed in a region where the distance between the first convex portion CV1 and the second convex portion CV2 is wide and the distance between the third convex portion CV3 and the fourth convex portion CV4 is narrow. The second recess DN2 has a shape obtained by rotating the first recess DN1 90 degrees in a planar view, and is formed in an area where the distance between the first convex portion CV1 and the second convex portion CV2 is narrow and the distance between the third convex portion CV3 and the fourth convex portion CV4 is wide.

[0022] The above adhesive sheet AS is used, for example, for wallpaper, decorative sheets, automobile decals to replace automobile paint, automobile paint protection films, medical tapes, protective films for displays such as curved displays, protective films for automobile glass, etc.

[0023] Here, when the adhesive sheet AS is attached to the surface of the adherend, the adhesive sheet AS may be bent depending on the shape of the surface. For example, as shown in FIG. 3, when the adhesive sheet AS is bent so that the substrate BS is convex upward, and a tension TF1 in the left-right direction acts on the substrate BS as shown in FIG. 1, stress is concentrated at the intersection position of the first to fourth convex parts CV1 to CV4, and a moment M due to the shape of the convex parts CV is generated. This moment M causes the convex parts CV to be stretched in the front-rear direction perpendicular to the left-right direction, and the entire adhesive sheet AS extends in the front-rear direction and exhibits a negative Poisson's ratio. That is, when the adhesive sheet AS is bent in one direction and tension TF1 is applied to the substrate BS, the substrate BS is also pulled in the perpendicular direction and tension TF2 is applied, improving the curved surface conformability of the adhesive sheet AS. Note that when the adhesive sheet AS is bent so that the substrate BS is concave upward, and a compression force in the left-right direction acts on the substrate BS, the substrate BS is compressed in the front-rear direction in the same manner, and a compression force is applied, improving the curved surface conformability of the adhesive sheet AS. Therefore, the adhesive sheet AS can conform to the shape of the adherend surface, and the adhesive sheet AS can be prevented from peeling off from the adherend surface over time.

[0024] According to the above embodiment, since the base material BS of the adhesive sheet AS has an auxetic structure, when the adhesive sheet AS is bent in one direction and tension TF1 or compression force is applied to the base material BS, tension TF2 or compression force is also applied to the base material BS in the perpendicular direction, thereby improving the curved surface conformability of the adhesive sheet AS.

[0025] As described above, the best configuration, method, etc. for carrying out the present invention are disclosed in the above description, but the present invention is not limited thereto. That is, the present invention is mainly illustrated and described with respect to a specific embodiment, but a person skilled in the art can make various modifications to the above-described embodiment in terms of shape, material, quantity, and other detailed configurations without departing from the scope of the technical idea and purpose of the present invention. In addition, the description of the shape, material, etc. disclosed above, which is limited, is illustratively described to facilitate understanding of the present invention, and does not limit the present invention, so that the description of the names of the members from which some or all of the limitations of the shape, material, etc. are removed is included in the present invention.

[0026] The sheet of the present invention may be a sheet other than the adhesive sheet AS, for example, as shown in Figures 1 to 3, it may be a pressure-sensitive adhesive sheet PS having an auxetic structure similar to the adhesive sheet AS, or an outer sheet ES having an auxetic structure similar to the adhesive sheet AS.

[0027] The adhesive sheet PS comprises an adhesive layer PD and a substrate BS supporting the adhesive layer PD, and the substrate BS has an auxetic structure. In this case, the substrate BS has an unevenness consisting of convex portions CV and concave portions DN formed on its non-adhesive surface BS1 (the surface opposite to the adhesive surface PD1 of the adhesive sheet PS), and the unevenness constitutes an auxetic structure. The adhesive sheet PS may be used, like the adhesive sheet AS, for example, as wallpaper, decorative sheets, automotive decals that replace automotive paint, automotive paint protection films, medical tapes, protective films for displays such as curved displays, protective films for automotive glass, etc., or may be used for purposes other than those of the adhesive sheet AS. The substrate BS of the adhesive sheet PS may be made of any material depending on the purpose of the adhesive sheet PS and the type and material of the adhesive layer PD, for example, the same material as the substrate BS of the adhesive sheet AS, and may have a thickness of 10 μm to 2 mm.

[0028] The exterior sheet ES comprises a decorative surface layer ED having a decorative surface ED1 decorated with a shape, color, pattern, letters, etc., and a substrate BS as a surface layer that supports the decorative surface layer ED and includes a non-adhesive surface BS1 as one surface of the exterior sheet ES, and the substrate BS has an auxetic structure. In this case, the substrate BS has an unevenness formed of a convex portion CV and a concave portion DN on the non-adhesive surface BS1, and the auxetic structure is formed by the unevenness. The exterior sheet ES is used, for example, as a seat exterior sheet that covers a vehicle seat as an object to be decorated, a protective sheet that wraps fruits and vegetables to prevent them from being damaged during transportation, and the like, and is used to wrap the object to be decorated or wrapped around the object to form the exterior of the object to be decorated. For example, when the exterior sheet ES is used as a seat exterior sheet, not only can the curved surface followability of the exterior sheet ES be improved when it is processed into the shape of the seat, but the exterior sheet ES can also flexibly deform when the weight of the person sitting on it is applied, improving the comfort of sitting. The base material BS of the exterior sheet ES may be made of any material depending on the application and type and material of the decorative surface layer ED of the exterior sheet ES, such as plastic, cellulose, rubber, knitted fabric, woven fabric, nonwoven fabric, or the same material as the base material BS of the adhesive sheet AS or pressure-sensitive adhesive sheet PS, and may have a thickness of 100 μm to 30 mm. The decorative surface layer ED may be made of any material depending on the application and type and material of the substrate BS of the exterior sheet ES, such as thermoplastic resins such as polyethylene and polypropylene, and composite resins such as urethane resin and vinyl chloride resin, and may have a thickness of 10 μm to 2 mm.

[0029] The adhesive sheet AS, pressure sensitive adhesive sheet PS, and exterior sheet ES may be used as an impact absorbing sheet that absorbs impact by being provided on the inner surface of a member that is subjected to impact, such as a helmet or protector. As long as the substrate BS has an auxetic structure, the adhesive sheet AS or the adhesive sheet PS may be, for example, a two-layer structure in which the substrate BS is laminated with an adhesive layer AD or a pressure-sensitive adhesive layer PD, a three-layer structure or a structure with three or more layers in which one or more intermediate layers are laminated between the substrate BS and the adhesive layer AD or the pressure-sensitive adhesive layer PD, or a structure in which the substrate BS or the intermediate layer is provided in a peelable manner, etc. The adhesive sheet AS or the pressure sensitive adhesive sheet PS may be configured as an exterior sheet ES. In this case, the substrate BS corresponds to a surface layer including a non-adhesive surface BS1 as one surface of the exterior sheet ES, and the substrate BS has an auxetic structure in which irregularities consisting of convex portions CV and concave portions DN are formed on the non-adhesive surface BS1. In addition, when the non-adhesive surface BS1 is decorated with a shape, color, pattern, character, or the like, the substrate BS also corresponds to a decorative surface layer ED having the non-adhesive surface BS1 as a decorative surface ED1.

[0030] The decorative surface layer ED of the exterior sheet ES may have an auxetic structure. In this case, the decorative surface layer ED corresponds to a surface layer including a decorative surface ED1 as one surface of the exterior sheet ES, and an auxetic structure is formed on the decorative surface ED1 by forming irregularities consisting of convex portions CV and concave portions DN. In this case, the irregularities constituting the auxetic structure may be used as decoration, or other decorations may be applied to the decorative surface ED1. As long as the surface layer of the exterior sheet ES has an auxetic structure, it may be, for example, a single layer having only the decorative surface layer ED as the surface layer, a two-layer structure in which the substrate BS and the decorative surface layer ED are laminated, a three-layer or more layer structure in which one or more intermediate layers are laminated between the substrate BS and the decorative surface layer ED, a structure in which the substrate BS or the intermediate layer is peelably arranged, etc., or only the substrate BS may have an auxetic structure, or only the decorative surface layer ED may have an auxetic structure, or both the decorative surface layer ED and the substrate BS may have an auxetic structure, or at least one of the substrate BS and the decorative surface layer ED and the intermediate layer may have an auxetic structure.

[0031] The substrate BS and the decorative surface layer ED may have an auxetic structure with a shape other than that shown in the embodiment. For example, as shown in Figure 4, convex portions CV and concave portions DN of different shapes from those in the embodiment may be formed, and the auxetic structure may be constituted by the unevenness. Alternatively, as shown in Figures 5(A) to (E), the substrate BS and the decorative surface layer ED may have an auxetic structure consisting of a reentrant structure. Alternatively, as shown in Figures 6(A) and (B), the substrate BS and the decorative surface layer ED may have an auxetic structure consisting of a chiral structure. In FIG. 4, the convex portion CV is composed of a plurality of first convex portions CV5 extending in the left-right direction and a plurality of second convex portions CV6 extending in the front-rear direction, and the intersections of the first convex portions CV5 and the second convex portions CV6 are formed in a swastika shape. The first convex portion CV5 has a substantially sinusoidal shape that is linear across a region where the displacement of the sinusoidal waveform is zero. The second protrusion CV6 has a generally sinusoidal shape extending in the front-rear direction in the same shape as the first protrusion CV5, and is generally perpendicular to the first protrusion CV5 at the intersection with the first protrusion CV5. The recess DN shown in Fig. 4 is formed in a region surrounded by the first convex portion CV5 and the second convex portion CV6, and is defined by these convex portions CV5 and CV6. Note that all of the recesses DN have the same shape. In Figures 5(A) to (E) and Figures 6(A) and (B), the convex portion CV is the portion depicted by the double line, and the concave portion DN is the portion surrounded by the convex portion CV. Note that Figures 5(A) to (E) and Figures 6(A) and (B) depict only a portion of the area, and in reality, the convex portion CV and the concave portion DN are connected to each other more than is shown in the figures.

[0032] The substrate BS and the decorative surface layer ED may have an auxetic structure formed by cutouts penetrating the substrate BS and the decorative surface layer ED, instead of the unevenness formed by the convex portions CV and the concave portions DN. For example, instead of the concave portions DN, the first concave portions DN1, and the second concave portions DN2, the regions of the concave portions DN, DN1, and DN2 may be cut out so as to penetrate the substrate BS and the decorative surface layer ED. For example, as shown in Fig. 7, the substrate BS may be cut out to form cutout portions CT, the first cutout portion CT1, and the second cutout portion CT2, and the auxetic structure may be formed by the unevenness formed by the convex portions CV and the cutout portions CT. The cutout portions CT, CT1, and CT2 are formed, for example, by cutting the substrate BS before the unevenness is formed, using a cutting means such as a cutting blade, so as to reach the adhesive layer AD, the pressure-sensitive adhesive layer PD, and the decorative surface layer ED. The thickness of the uneven layer of the base material BS or the decorative surface layer ED may be 30% or less of the sheet thickness, and the area ratio of the convex portions CV to the non-adhesive surface BS1 or the decorative surface ED1 may be 30% or more. The decorative surface layer ED may be made of a material other than those shown in the embodiment, and may be made of a metal such as aluminum, for example. The substrate BS and decorative surface layer ED may have an auxetic structure, i.e., a negative Poisson's ratio, and the shape of the substrate BS and decorative surface layer ED may be an auxetic structure so as to have a negative Poisson's ratio, or the molecular structure of the substrate BS and decorative surface layer ED may be an auxetic structure so as to have a negative Poisson's ratio.

[0033] The material, type, shape, etc. of the adhesive sheet AS, the adhesive sheet PS, the exterior sheet ES, the substrate BS, the adhesive layer AD, the adhesive layer PD, the decorative surface layer ED, and the adherend are not particularly limited. For example, the adhesive sheet AS, the adhesive sheet PS, the exterior sheet ES, the substrate BS, the adhesive layer AD, the adhesive layer PD, the decorative surface layer ED, and the adherend may be circular, elliptical, polygonal such as triangular or rectangular, or other shapes, or may be strip-shaped or sheet-shaped. Furthermore, the adherend may be, for example, a single object such as food, a resin container, a semiconductor wafer such as a silicon semiconductor wafer or a compound semiconductor wafer, a circuit board, an information recording substrate such as an optical disk, a glass plate, a steel plate, a ceramic, a wooden board, or a resin, or may be a composite formed of two or more of them, or may be a person, an animal, or a plant. The adhesive sheet AS and the adhesive sheet PS may be, for example, any sheet, film, tape, etc., such as an information label, a decorative label, a protective sheet, a dicing tape, a die attach film, a die bonding tape, or a recording layer-forming resin sheet.

[0034] The means and steps in the above embodiment are not limited in any way as long as they can perform the operations, functions, or steps described for those means and steps, and are not limited in any way to the components and steps of a single embodiment shown in the above embodiment. For example, the cutting means may be any means that cuts out the base material or decorative surface layer, and is not limited in any way as long as it is within the technical scope in light of the common general technical knowledge at the time of filing (the same applies to other means and steps).

[0035] In the above-described embodiments, when a cutting means or member that cuts a workpiece or forms an incision or cutting line in the workpiece is used, a cutter blade, laser cutter, ion beam, fire, heat, water pressure, heating wire, spraying of gas or liquid, etc. may be used instead of or in combination with the above-described examples, or a cutter that cuts by moving the cutter using a combination of appropriate driving equipment may be used.

[0036] The driving equipment may be electric equipment such as rotary motors, linear motors, single-axis robots, so-called multi-joint robots with joints on two or three or more axes, actuators such as air cylinders, hydraulic cylinders, rodless cylinders and rotary cylinders, etc., which may be used alone, or a direct or indirect combination of such electric equipment and actuators may be used, and electric equipment, actuators, etc. may or may not be capable of torque control or speed control of the output parts thereof. [Explanation of symbols]

[0037] AS…adhesive sheet AD…adhesive layer BS…Base material (base material, surface layer) ES: Exterior sheet PS...adhesive sheet PD…adhesive layer

Claims

1. An adhesive sheet, An adhesive layer; A substrate supporting the adhesive layer, An adhesive sheet characterized in that the substrate has an auxetic structure.

2. An adhesive sheet, An adhesive layer; A substrate supporting the pressure-sensitive adhesive layer, An adhesive sheet characterized in that the substrate has an auxetic structure.

3. The sheet according to claim 1 or claim 2, characterized in that the auxetic structure is constituted by irregularities formed on the substrate.

4. 3. A sheet as claimed in claim 1 or claim 2, characterized in that the auxetic structure is constituted by cutouts formed in the substrate.

5. An exterior sheet, A surface layer including one surface of the exterior sheet is provided, An exterior sheet characterized in that the surface layer has an auxetic structure.

6. The exterior sheet according to claim 5, characterized in that the auxetic structure is constituted by irregularities formed on the surface layer.

7. 6. An exterior sheet according to claim 5, characterized in that the auxetic structure is constituted by cutouts formed in the surface layer.

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