Release sheet

Abstract

To provide a release sheet with enhanced releasability.SOLUTION: A release sheet RL is a sheet that is releasable from a temporarily attached adhesive sheet or tacky sheet, and includes a release layer RA, the release layer RA having an auxetic structure.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a release sheet. [Background technology]

[0002] 2. Description of the Related Art A release sheet that is peeled off from a temporarily attached adhesive sheet or pressure sensitive adhesive sheet is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-14580 Summary of the Invention [Problem to be solved by the invention]

[0004] The functional film (release sheet) described in Patent Document 1 has an uneven surface, but has the disadvantage that the release properties for the adhesive sheet or pressure-sensitive adhesive sheet are insufficient.

[0005] An object of the present invention is to provide a release sheet capable of improving releasability. [Means for solving the problem]

[0006] A release sheet according to one embodiment of the present invention is a release sheet that is peeled off from a temporarily attached adhesive sheet or pressure sensitive adhesive sheet, and comprises a release layer, the release layer having an auxetic structure.

[0007] The release sheet according to one aspect of the present invention may further include a substrate supporting the release layer.

[0008] In the release sheet according to one embodiment of the present invention, the auxetic structure may be formed by irregularities formed on the release layer.

[0009] In a release sheet according to one aspect of the present invention, the auxetic structure may be formed by cutouts formed in the release layer. Effect of the Invention

[0010] According to the present invention, since the release layer of the release sheet has an auxetic structure, simply pulling the release sheet in one direction to apply tension also causes the release sheet to be pulled in the perpendicular direction to apply tension, and therefore, by simply stretching the release sheet in one direction, shear stresses in two directions perpendicular to each other can be applied to the interface between the adhesive sheet or pressure sensitive adhesive sheet and the release layer, thereby improving the releasability of the release sheet. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is an explanatory diagram of a release sheet according to one embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of the release sheet of FIG. 1 taken along line II-II. [Diagram 3] FIG. 4 is an explanatory diagram of a release sheet being peeled off. [Figure 4] FIG. 11 is an explanatory diagram of a release sheet according to a modified example of the present invention. [Diagram 5] FIG. 11 is an explanatory diagram of a release sheet according to a modified example of the present invention. [Figure 6] FIG. 11 is an explanatory diagram of a release sheet according to a modified example of the present invention. [Figure 7] FIG. 11 is an explanatory diagram of a release sheet according to a modified example of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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.

[0013] 1 and 2, the release sheet RL is a sheet to be peeled off from the temporarily attached adhesive sheets AS1, AS2 or pressure sensitive adhesive sheets PS1, PS2 (see FIG. 3), and comprises a release layer RA having an auxetic structure and a substrate BS supporting the release layer RA. Note that an auxetic structure is a structure having a negative Poisson's ratio, i.e., a structure that exerts a negative Poisson's effect.

[0014] The substrate BS may be made of any material, such as paper, laminated paper, plastic, cellulose, rubber, etc., depending on the use of the release sheet RL and the type and material of the release layer RA, 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.

[0015] The release layer RA may be made of any material having easy peelability depending on the application of the release sheet RL and the type and material of the substrate BS, for example, a thermoplastic resin such as polyethylene or polypropylene, and has a thickness of 10 μm to 2 mm.

[0016] Here, the release layer RA has a release surface RA1 (the surface opposite to the substrate BS) that is peeled off from the adhesive sheet AS1, AS2 or the pressure sensitive adhesive sheet PS1, PS2, on which unevenness consisting of convex portions CV and concave portions DN is formed, and the unevenness constitutes an auxetic structure. Such a release layer RA is formed, for example, by embossing the release layer RA laminated on the substrate BS before the unevenness is formed, or by laminating the release layer RA on the substrate BS using a three-dimensional printer so that 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 release sheet RL.

[0017] The convex portion CV is composed of a first convex portion CV1 and a second convex portion CV2 each extending in the left-right direction as a first direction, and a third convex portion CV3 and a fourth convex portion CV4 each extending in the front-rear direction as a second direction perpendicular to the first direction. The convex portion CV is formed such that in a region where the distance between the first convex portion CV1 and the second convex portion CV2 is wide, the distance between the third convex portion CV3 and the fourth convex portion CV4 is narrow, and in a region where the distance between the first convex portion CV1 and the second convex portion CV2 is narrow, the distance between the third convex portion CV3 and the fourth convex portion CV4 is wide. The area ratio of the convex portion CV to the release surface RA1 of the release layer RA 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.

[0018] 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.

[0019] The release sheet RL described above, for example, as shown in FIG. 3(A), constitutes an original roll RS together with an adhesive sheet AS1 temporarily attached to the release sheet RL, and is peeled off by peeling means 20 from the adhesive sheet AS1 of the original roll RS unwound by unwound means 10, or, as shown in FIG. 3(B), is peeled off by peeling means 30 from the adhesive sheet AS2 affixed to the adherend WK.

[0020] 3(A), the pay-out means 10 includes a support roller 11 supported by the output shaft of a rotary motor 11A as a drive device and supporting the original web RS, and a drive roller 12 supported by the output shaft of a rotary motor 12A as a drive device and sandwiching the release sheet RL with a pinch roller 12B. The peeling means 20 includes a peeling roller 21 as a peeling member that folds back the release sheet RL and peels it off from the adhesive sheet AS1, and a recovery roller 22 supported by the output shaft of a rotary motor 22A as a drive device and serving as a recovery means that recovers the release sheet RL.

[0021] 3B, the peeling means 30 includes a support roller 31 that supports the strip-shaped peeling tape PT, a guide roller 32 that guides the peeling tape PT, a peeling roller 34 as a peeling member rotatably supported on an output shaft 33A of a linear motor 33 as a driving device, a drive roller 35 that is supported on an output shaft of a rotating motor 35A as a driving device and pinches the peeling tape PT with a pinch roller 35B, a recovery roller 36 that is supported on an output shaft of a rotating motor 36A as a driving device and recovers the peeling tape PT, and a support table 38 that is supported on a slider 37A of a linear motor 37 as a driving device and has a support surface 38A that can be sucked and held by a decompression means (not shown) such as a decompression pump or a vacuum ejector. When the peeling means 30 peels off the release sheet RL, the peeling means 30 drives the linear motor 37 to move the support table 38 leftward, and when the left end of the adhesive sheet AS2 reaches just below the lowest part of the peeling roller 34, the driving of the linear motor 37 is stopped. Next, the peeling means 30 drives the linear motor 33 to lower the peeling roller 34 to apply the peeling tape PT to the left end of the adhesive sheet AS2, and then drives the linear motor 37 and the rotary motors 35A, 36A to move the support table 38 leftward and rotate the support roller 31 and the drive roller 35 in accordance with the moving speed. As a result, the release sheet RL is peeled off from the adhesive sheet AS2 applied to the adherend WK, and the peeled release sheet RL is collected by the collection roller 36 together with the peeling tape PT.

[0022] Here, when the release sheet RL is peeled off, as shown in FIG. 1, a unidirectional tension TF1 acts on the release sheet RL. For example, when the release sheet RL is pulled in the left-right direction, as shown in FIG. 1, stress is concentrated at the intersections of the first to fourth convex portions CV1 to CV4, and a moment M due to the shape of the convex portion CV is generated. This moment M causes the convex portion CV to be stretched in the front-rear direction perpendicular to the left-right direction, and the entire release sheet RL is stretched in the front-rear direction and exhibits a negative Poisson's ratio. Therefore, by simply pulling the release sheet RL in one direction to apply tension TF1, the release sheet RL is also pulled in the perpendicular direction to apply tension TF2. Therefore, by only stretching the release sheet RL in one direction, shear stresses in two directions perpendicular to each other can be applied to the interfaces between the adhesive sheets AS1 and AS2 temporarily attached to the release layer RA and the release layer RA.

[0023] This effect of the auxetic structure occurs when tension TF1 is applied to the release surface RA1 of the release layer RA, and therefore occurs not only when the release sheet RL is pulled in the direction of its surface, but also when the release sheet RL is bent during peeling. Therefore, this effect occurs even when the peel angle of the release sheet RL is small, and promotes the peeling of the release sheet RL.

[0024] According to the above embodiment, since the release layer RA of the release sheet RL has an auxetic structure, simply pulling the release sheet RL in one direction to apply tension TF1 also pulls the release sheet RL in the perpendicular direction to apply tension TF2. Therefore, by simply stretching the release sheet RL in one direction, shear stresses in two directions perpendicular to each other can be applied to the interfaces between the adhesive sheets AS1, AS2 and the release layer RA, improving the releasability of the release sheet RL from the adhesive sheets AS1, AS2.

[0025] In addition, since the release sheet RL has a substrate BS that supports the release layer RA, the strength of the release sheet RL, which may be reduced by making the release layer RA an auxetic structure, can be compensated for by the substrate BS, thereby preventing a reduction in the strength of the release sheet RL.

[0026] 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.

[0027] As long as the release layer RA has an auxetic structure, the release sheet RL may be, for example, a single layer consisting of only the release layer RA, a two-layer consisting of the substrate BS and the release layer RA laminated together, a three-layer or more layer consisting of the substrate BS and the release layer RA with one or more intermediate layers laminated between them, or one in which the substrate BS or the intermediate layer is provided in a peelable manner. In the release sheet RL, only the release layer RA may have an auxetic structure, or both the release layer RA and the substrate BS may have an auxetic structure, or at least one of the substrate BS and the intermediate layer and the release layer RA may have an auxetic structure. As shown in FIGS. 3(A) and 3(B), the release sheet RL may be formed by temporarily attaching adhesive sheets PS1 and PS2 instead of the adhesive sheets AS1 and AS2, and then peeling the release sheet RL from the adhesive sheets PS1 and PS2. The release sheet RL may have a release agent layer laminated on the release layer RA so as to follow the unevenness of the release layer RA, i.e., to have the same unevenness as the release layer RA. By providing such a release agent layer, the releasability of the release sheet RL can be further improved. The release agent layer may be composed of, for example, a silicone-based release agent, an alkyl pendant-based release agent, a condensation wax-based release agent, a fluorine-based release agent, a polyester-based release agent, or the like, or may be composed of a plating treatment such as hard chrome plating (also called hard chrome plating) or a DLC (Diamond-Like Carbon) film, or a surface treatment using an inorganic material, or the like.

[0028] The release layer RA 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 an auxetic structure may be formed by the concaves and convexes, or it may have an auxetic structure consisting of a reentrant structure as shown in Figures 5(A) to (E), or it may have an auxetic structure consisting of a chiral structure as shown in Figures 6(A) and (B). 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.

[0029] The release layer RA may have an auxetic structure formed by cutouts penetrating the release layer RA 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 release layer RA. For example, as shown in FIG. 7, cutout portions CT, first cutout portions CT1, and second cutout portions CT2 may be formed by cutting out the release layer RA, and the unevenness formed by the convex portions CV and the cutout portions CT may form an auxetic structure. The cutout portions CT, CT1, and CT2 may be formed, for example, by cutting out the release layer RA before the unevenness is formed, which is laminated on the substrate BS, with a cutting means such as a cutting blade so as to reach the substrate BS, or by laminating the release layer RA on the substrate BS with a three-dimensional printer so as to form the cutout portions CT. The release layer RA may have a thickness of the concave-convex layer that is 30% or less of the thickness of the release sheet RL, and the area ratio of the convex portions CV to the release surface RA1 may be 30% or more. The release layer RA may be made of a material other than those shown in the embodiment, and may be made of a metal such as aluminum. The release layer RA may have an auxetic structure, i.e., a negative Poisson's ratio, and the shape of the release layer RA may be an auxetic structure so that it has a negative Poisson's ratio, or the molecular structure of the release layer RA may be an auxetic structure so that it has a negative Poisson's ratio.

[0030] The material, type, shape, etc. of the adhesive sheets AS1, AS2, the adhesive sheets PS1, PS2, the release sheet RL, the substrate BS, the release layer RA, and the adherend WK are not particularly limited. For example, the adhesive sheets AS1, AS2, the adhesive sheets PS1, PS2, the release sheet RL, the substrate BS, the release layer RA, and the adherend WK may be circular, elliptical, polygonal such as triangular or rectangular, or other shapes, or may be strip-shaped or sheet-shaped. In addition, the adhesive sheets AS1, AS2 and the adhesive sheets PS1, PS2 may be, for example, a single layer of only an adhesive layer or a pressure-sensitive adhesive layer, a two-layered sheet in which a substrate and an adhesive layer or a pressure-sensitive adhesive layer are laminated, a three-layered sheet or three or more layers in which one or more intermediate layers are laminated between a substrate and an adhesive layer or a pressure-sensitive adhesive layer, a sheet in which a substrate or an intermediate layer is provided releasably, a double-sided adhesive sheet or a double-sided pressure-sensitive adhesive sheet of a single layer consisting of only an adhesive layer or a pressure-sensitive adhesive layer, a double-sided adhesive sheet or a double-sided pressure-sensitive adhesive sheet in which an adhesive layer is laminated on both outermost surfaces of one or more intermediate layers, etc. Furthermore, the adherend WK 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 plate, a wooden board, or a resin, or may be a composite formed of two or more of these, and may be any type of member or article. The adhesive sheets AS1, AS2 and the pressure-sensitive adhesive sheets PS1, PS2 may be 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, a recording layer-forming resin sheet, etc.

[0031] 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 at all to the components and steps of a single embodiment shown in the above embodiment. For example, the peeling means may be anything that peels off the release sheet from the temporarily attached adhesive sheet or pressure-sensitive adhesive sheet, 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).

[0032] The driving equipment in the above-described embodiments may be electric equipment such as rotary motors, linear motors, single-axis robots, so-called multi-joint robots having joints on two or three or more axes, actuators such as air cylinders, hydraulic cylinders, rodless cylinders, and rotary cylinders, 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 for the output parts of such electric equipment, actuators, etc. may be used.

[0033] In the above embodiment, there is a certain object (hereinafter referred to as "object A") and an object (hereinafter referred to as "object B") that moves relative to object A. In other words, object A and object B that move relatively may be object B moving relative to object A, which does not move, object A may move relative to object B, which does not move, or both objects A and B may move. If the result achieved by the movement is the same, either object A or object B may move. If a rotating member such as a roller is used, a driving device that rotates the rotating member may be provided. The surface of the rotating member or the rotating member itself may be made of a deformable member such as rubber or resin. The surface of the rotating member or the rotating member itself may be made of a non-deformable member. Other members such as a rotating or non-rotating shaft or blade may be used instead of the roller. If a peeling means or peeling member such as a peeling plate or peeling roller that peels off the object to be peeled is used, the above examples may be used. Alternatively or in combination, a plate-shaped member, a round bar, a roller, or the like may be used, the peeling member may be made of a deformable member such as rubber or resin, or may be made of a non-deformable member, and when a supporting (holding) means or a supporting (holding) member that supports (holds) a supported member (held member) is used, a gripping means such as a mechanical chuck or a chuck cylinder, Coulomb force, adhesive (adhesive sheet, adhesive tape), pressure sensitive adhesive (adhesive sheet, adhesive tape), magnetic force, Bernoulli adsorption, suction adsorption, a driving device, or the like may be used to support (hold) the supported member, and when a cutting means or a cutting member that cuts a member to be cut or forms an incision or cutting line in a member to be cut is used, a cutter blade, a laser cutter, an ion beam, fire, heat, water pressure, an electric heating wire, a spray of gas or liquid, or the like may be used to cut, or a suitable combination of driving devices may be used to move the cutting means to cut. [Explanation of symbols]

[0034] AS1, AS2...Adhesive sheet BS…Base material PS1, PS2...adhesive sheet RA…Release layer RL…Release sheet

Claims

1. A release sheet that is peeled off from a temporarily attached adhesive sheet or pressure-sensitive adhesive sheet, A release layer is provided, A release sheet characterized in that the release layer has an auxetic structure.

2. The release sheet according to claim 1 , further comprising a substrate supporting the release layer.

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

4. A release sheet according to claim 1 or claim 2, characterized in that the auxetic structure is constituted by cutouts formed in the release layer.

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