Electronic Components

Abstract

To provide an electronic component having a pressure sensitive adhesive sheet capable of being quickly peeled, having no contamination due to an adhesive agent after the peeling, being extended and peeled from the other end part until the last even if disconnected in the middle of the extension and peeling from one end part, and having preferable adhesive force in the use.SOLUTION: An electronic component comprises a pressure sensitive adhesive sheet of which one front surface is bonded so that at least one part is linear to a first bonding object and the other front surface is bonded to a second bonding object, and at least two end parts are bonded to the second bonding object in a state where they are exposed from the second bonding object, and which can be extended and peeled. The at least two end parts exposed from the second bonding object can be expanded while being gripped, and at least any one of the first bonding object and the second bonding object is a recovery component. The recovery component is at least any one of a display glass and a battery.SELECTED DRAWING: Figure 2B

Description

[Technical Field]

[0001] The present invention relates to electronic components. [Background technology]

[0002] Pressure-sensitive adhesive sheets (sometimes referred to as "adhesive tapes") are widely used as a joining means with excellent workability and high adhesive reliability in situations such as fastening components that make up electronic devices. Specifically, pressure-sensitive adhesive tapes are used for component fixing applications in various industrial fields, such as fixing metal plates that make up relatively large electronic devices such as flat-screen televisions, home appliances, and office automation equipment, fixing exterior components to housings, fixing exterior components and rigid components such as batteries to relatively small electronic devices such as mobile electronic terminals, cameras, and personal computers, temporarily fixing such components, as well as for labeling purposes that display product information.

[0003] In recent years, in the above-mentioned industrial fields, for the purpose of resource conservation and from the viewpoint of protecting the global environment, it has become common to disassemble reusable or reusable parts used in products after use and reuse them. In this case, if adhesive tape is used, it is necessary to peel the adhesive tape attached to the parts. However, since such adhesive tape usually has high adhesive strength and is attached to many locations in the product, the work of peeling it off involves considerable labor. Therefore, there is a demand for easy peeling and removal during the reuse or re-use process, thereby reducing the labor costs.

[0004] As an easily peelable and removable adhesive tape, a tape has been proposed that includes an adhesive portion and a tab portion, the tab portion being attached so as to protrude from one of the outermost portions of a first adherend and the second adherend and be capable of being clamped, and that can be peeled by clamping the tab portion and stretching it in a direction substantially parallel to the adhesive surface (see Patent Document 1). However, when the tab portion (gripping portion) for stretch-peeling is only at one end, as in this proposed adhesive tape, there is a problem in that the adhesive remains on the adhesive surface of the adhesive tape opposite the side having the tab portion (i.e., the surface to which the adhesive tape adheres for the longest period of time during peeling) after peeling, causing contamination. Another problem is that if the tab portion at one end is torn during stretch-peeling, it cannot be peeled any further, making it impossible to further dismantle reusable or reusable parts, etc.

[0005] In response to this, an adhesive film has been proposed (see Patent Document 2), which includes an adhesive region (2) adjacent to a grip tab (1) located at one end of the adhesive film strip and extending toward the other end (3), as shown in FIG. 1. The adhesive region (2) includes, in order from the grip tab (1) toward the other end (3) of the adhesive film strip, a first adhesive region (4) having a larger cross-sectional area than the second adhesive region (5), a second adhesive region (5) having a cross-sectional area that rapidly decreases toward the end (3), and a third adhesive region (6) forming the end (3) and terminating in one or more tips (7) toward the end (3). However, the shape of this proposed adhesive film poses the problem of a small adhesive area, which makes it difficult to effectively utilize the available adhesive area and weakens the adhesive strength. Peeling of components constituting the electronic device during use is a major problem, and adhesive strength must be maintained until the electronic components are recovered for reuse or re-use.

[0006] Therefore, there is a strong demand for electronic components that include an adhesive sheet that can be quickly peeled off, that is not contaminated by the adhesive after peeling, that can be stretched and peeled from the other end to the end even if it tears during stretch-peeling from one end, and that has suitable adhesive strength when in use. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-124289 [Patent Document 2] U.S. Patent No. 6,680,096 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to solve the above-mentioned conventional problems and achieve the following objectives: Namely, the present invention aims to provide an electronic component equipped with an adhesive sheet that can be quickly peeled, is not contaminated by the adhesive after peeling, and even if it tears during stretch-peeling from one end, can be stretch-peeled from the other end to the end, and has suitable adhesive strength during use. [Means for solving the problem]

[0009] The means for solving the above problems are as follows. That is, it is an electronic component characterized by having an adhesive sheet having one surface attached to a first attachment object so that at least a portion of the surface is linear, and the other surface attached to a second attachment object, and having at least two ends exposed from the second attachment object. [Effects of the Invention]

[0010] According to the present invention, the above-mentioned problems in the prior art can be solved, the above-mentioned object can be achieved, and an electronic component can be provided that is provided with an adhesive sheet that can be peeled quickly, is not contaminated by the adhesive after peeling, and even if it tears during stretch-peeling from one end, it can be stretch-peeled from the other end to the end and peeled all the way through, and has suitable adhesive strength when in use. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows a prior art adhesive film. [Figure 2A] FIG. 2A is a schematic explanatory diagram (top view) showing one embodiment of the electronic component of the present invention. [Figure 2B] FIG. 2B is a schematic explanatory diagram (cross-sectional view) showing one embodiment of the electronic component of the present invention. [Figure 2C] FIG. 2C is a schematic explanatory view (cross-sectional view) showing another embodiment of the electronic component of the present invention. [Figure 2D] FIG. 2D is a schematic explanatory diagram (top view) showing another embodiment of the electronic component of the present invention. [Figure 2E] FIG. 2E is a schematic explanatory diagram (top view) showing another embodiment of the electronic component of the present invention. [Figure 2F] FIG. 2F is a schematic explanatory diagram (top view) showing another embodiment of the electronic component of the present invention. [Figure 2G] FIG. 2G is a schematic explanatory diagram (top view) showing another embodiment of the electronic component of the present invention. [Figure 3A] FIG. 3A is a schematic explanatory diagram (cross-sectional view) of a case where the electronic component of the present invention is a battery. [Figure 3B] FIG. 3B is a schematic explanatory diagram (top view) of the electronic component of the present invention when it is a battery. [Figure 3C] FIG. 3C is a schematic explanatory view (cross-sectional view) showing another embodiment in which the electronic component of the present invention is a battery. [Figure 4A] FIG. 4A is a schematic explanatory diagram (cross-sectional view) of an electronic component of the present invention that is a television display. [Figure 4B] FIG. 4B is a schematic explanatory diagram (top view) of the electronic component of the present invention being a television display. [Figure 5A] FIG. 5A is a schematic explanatory diagram (cross-sectional view) of a method for attaching adhesive sheet 31 to acrylic plate 32 when evaluating impact resistance in the examples. [Figure 5B] FIG. 5B is a schematic explanatory diagram (top view) of a test piece prepared when evaluating impact resistance in the examples. [Figure 5C] FIG. 5C is a schematic explanatory diagram (cross-sectional view) of a method for placing a test piece on a U-shaped measurement table when evaluating impact resistance in the examples. [Figure 6A] FIG. 6A is a schematic explanatory diagram (cross-sectional view) of application mode X in Test Examples 1 to 11 and the stretch direction (horizontal direction) in the stretch peel test. [Figure 6B] FIG. 6B is a schematic explanatory diagram (cross-sectional view) of application mode X in Test Examples 1 to 11 and the stretch direction (vertical direction) in the stretch peel test. [Figure 6C] FIG. 6C is a schematic explanatory diagram (cross-sectional view) of application mode Y in Comparative Test Examples 1 to 11 and the stretch direction (horizontal direction) in the stretch peel test. [Figure 7A] FIG. 7A is a diagram showing the appearance of the acrylic plate after stretch peeling in the horizontal direction in Test Example 1 (application mode X). [Figure 7B] FIG. 7B is a diagram showing the appearance of the acrylic plate after stretch peeling in the horizontal direction in Test Example 1 (application mode Y). DETAILED DESCRIPTION OF THE INVENTION

[0012] (electronic parts) The electronic component comprises a pressure-sensitive adhesive sheet having one surface attached to a first attachment object so that at least a portion of the surface is linear, and the other surface attached to a second attachment object, the pressure-sensitive adhesive sheet being attached to the second attachment object with at least two ends exposed from the second attachment object. In this specification, the first attachment object and the second attachment object may be collectively referred to as the "adherend."

[0013] In this specification, the electronic components include not only various parts that constitute the electronic devices, such as sheet metal, exteriors, housings, and batteries, but also electronic devices themselves, such as televisions, home appliances, office automation equipment, mobile electronic devices, cameras, and personal computers.

[0014] The configuration of the electronic component will be specifically described below with reference to the drawings, but the present invention is not limited to these embodiments.

[0015] 2A and 2B, in the electronic component, one surface 21a of adhesive sheet 21 is attached to one surface of a first attachment target 22 constituting the electronic component, with at least a portion of the surface 21a being linear. Next, the other surface 21b of adhesive sheet 21 is attached to a second attachment target 23 constituting the electronic component. At this time, two longitudinal ends of adhesive sheet 21 are attached in a state where they are exposed from second attachment target 23. As a result, at least a portion of each end of adhesive sheet 21 exposed from second attachment target 23 functions as a gripping portion. FIG. 2C is a diagram showing another embodiment of the electronic component.

[0016] 2A to 2C show an example in which the adhesive sheet is attached to the attachment target in a linear fashion and has two ends. However, the adhesive sheet need only be attached so that one surface is at least partially linear with respect to the first attachment target. As shown in FIGS. 2D to 2G, the adhesive sheet may be attached to the first attachment target in a branched or bent shape. Therefore, the number of ends (gripping portions) of the adhesive sheet is not particularly limited and can be selected appropriately depending on the attachment shape of the adhesive sheet. In this case, the number of ends of the adhesive sheet exposed from the second attachment target is not particularly limited as long as it is at least two and can be selected appropriately depending on the purpose, but it is preferable that all ends are exposed from the second attachment target. Hereinafter, the ends of adhesive sheet 21 exposed from second attachment target 23 may be referred to as first gripping portion A, second gripping portion B, third gripping portion C, fourth gripping portion D, etc. 2A to 2G show an example in which the gripping portions A to D are not exposed from the first attachment object 22, but there is no particular limitation as long as at least two of the gripping portions A to D are exposed from at least the second attachment object 23, and at least one of the gripping portions A to D may be exposed from the first attachment object 22.

[0017] <Grip part> The gripping portion may be arranged directly on the first attachment target 22, as shown in Figures 2A and 2B, or may be arranged on the side (thickness direction surface) of the second attachment target 23, as shown in Figure 2C (first gripping portion A and second gripping portion B in Figures 2A to 2C), or may be arranged so as to be in contact with other elements of the electronic component adjacent to at least one of the first attachment target 22 and the second attachment target 23, although not shown in the figures.

[0018] The gripping portion is an end portion of the adhesive sheet, and the number of adhesive layers on the adhesive surface with at least one of the first and second attachment targets may be the same as or different from the number of adhesive layers on the gripping portion. For example, when the adhesive sheet has adhesive layers on both sides, the adhesive layer on at least one of the plurality of gripping portions may be arranged on only one side. Furthermore, the number of adhesive layers on the plurality of gripping portions may be the same as or different from each other.

[0019] The gripping portion may be formed by processing at least a portion of the edge of the pressure-sensitive adhesive sheet. The processing is not particularly limited and can be appropriately selected depending on the purpose, and examples include processing to remove the adhesive layer of the pressure-sensitive adhesive sheet, processing to place a release sheet on the surface of the adhesive layer of the pressure-sensitive adhesive sheet, and processing to modify the adhesive layer of the pressure-sensitive adhesive sheet to make it non-adhesive using a known means such as a release agent.

[0020] The release sheet is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include paper such as kraft paper, glassine paper, and wood-free paper; resin films such as polyethylene, polypropylene (biaxially oriented polypropylene (OPP), uniaxially oriented polypropylene (CPP)), and polyethylene terephthalate (PET); laminated paper in which the above-mentioned paper and a resin film are laminated together; and paper in which the above-mentioned paper has been sealed with clay, polyvinyl alcohol, or the like and one or both sides of which have been subjected to a release treatment with a silicone resin or the like. These may be used alone or in combination of two or more.

[0021] The length of the gripping portion is not particularly limited as long as it can be stretched, and can be appropriately selected depending on the distance between the first and second attachment objects and other electronic components adjacent to them, but is preferably 5 mm or more, more preferably 10 mm or more, and even more preferably 15 mm or more. The upper limit of the length is not particularly limited, and can be appropriately selected depending on the size of the electronic components, but is preferably 20 mm or less. The lengths of the gripping portions may be the same or different.

[0022] The width of the gripping portion is not particularly limited and can be appropriately selected depending on the width of the pressure-sensitive adhesive sheet, etc.

[0023] <Stretching direction p> The adhesive sheet 21 in the electronic component can be easily stretch-peeled by stretching it in the stretching direction p shown in Figures 2B and 2C. Figure 2B shows an embodiment in which the stretching direction p of the adhesive sheet 21 is horizontal (180° direction) relative to the attachment surface of the first attachment object 22 and the second attachment object 23, and Figure 2C shows an embodiment in which the stretching direction p of the adhesive sheet 21 is vertical (90° direction) relative to the attachment surface of the first attachment object 22 and the second attachment object 23, but there are no particular limitations on the angle of the stretching direction p relative to the attachment surface of the first attachment object 22 and the second attachment object 23, and it can be selected appropriately depending on the surrounding environment of the electronic component, etc.

[0024] The adhesive sheet in the electronic component may be peeled off by stretching the multiple gripping portions simultaneously, or may be peeled off in part by stretching one of the multiple gripping portions and then peeled off in the remaining part by stretching the other. Furthermore, the adhesive sheet in the electronic component has at least two ends exposed from the second attachment target, which is advantageous in that even if the adhesive sheet tears during stretch-peeling from one end (first gripping portion), it can be stretch-peeled from the other end (second gripping portion) to the end.

[0025] The removability of the pressure-sensitive adhesive sheet for the electronic component can be confirmed, for example, by the method described in "Evaluation of Removability 1" in the test examples described below. In the evaluation of removability, a sheet that is not contaminated by the pressure-sensitive adhesive after peeling and that can be stretch-peeled from the gripping portion at one end to the end even if it tears during stretch-peel from the gripping portion at the other end is considered to have excellent removability.

[0026] <Width of pasting area / Length of pasting area (X / Y)> When the width of the adhesive area of the pressure-sensitive adhesive sheet on the electronic component is X (cm) and the length of the adhesive area is Y (cm), the ratio of the width of the adhesive area to the length of the adhesive area, represented by [X / Y], is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 1 / 1 to 1 / 100,000, more preferably 1 / 1 to 1 / 10,000, and even more preferably 1 / 1 to 1 / 1,000. If the adhesive area ratio is less than 1 / 1, the adhesive strength may be insufficient, and if it exceeds 1 / 100,000, the pressure-sensitive adhesive sheet may tear during stretch-peeling or contamination by the adhesive may occur after peeling.

[0027] <First attachment target or second attachment target> The first and second pasting targets may be the same component or different components. Furthermore, the first and second pasting targets may be interchangeable.

[0028] The materials of the first and second attachment targets are not particularly limited and can be appropriately selected depending on the type of electronic component, etc. Examples include metals, alloys, glass, plastics, ceramics, etc. These may be used alone or in combination of two or more.

[0029] Specific examples of the first attachment object include a back chassis, a bezel, a metal plate, a housing, a heat dissipation sheet, and the like.

[0030] Specific examples of the second attachment target include display glass, batteries, heat dissipation members such as heat sinks, speakers, and camera lenses.

[0031] Among these, the first and second attachment targets are preferably recovered parts. The recovered parts are not particularly limited as long as they are reusable or recyclable parts, and can be appropriately selected depending on the purpose. Examples include recovered parts when defects occur during the manufacturing process of electronic components, and recovered parts when discarded. The adhesive sheet in the electronic component can be quickly peeled off, is not contaminated by the adhesive after peeling, and even if it tears during stretch-peeling from one end, it can be stretch-peeled from the other end to the end, so that at least one of the first and second attachment targets can be quickly recovered as the recovered parts, and is advantageous in that at least one of the first and second attachment targets is not contaminated when reused or re-used.

[0032] More specific embodiments of the electronic component will be described below with reference to the drawings, but the present invention is not limited to these embodiments.

[0033] An embodiment in which the electronic component is a small component such as a battery will be specifically described below. 3A and 3B, one surface 61a of adhesive sheet 61 is attached so that at least a portion thereof is linear with respect to a fixing portion of battery 63 on back chassis 62. Next, the other surface 61b of adhesive sheet 61 is attached to battery 63. At this time, two ends (first gripping portion A and second gripping portion B) in the length direction (extension direction) of adhesive sheet 61 are attached in a state where they are exposed from both ends of battery 63. Furthermore, the method of attaching first gripping portion A and second gripping portion B of adhesive sheet 61 may be an embodiment shown in FIG. 3C.

[0034] An embodiment in which the electronic component is a large component such as a television display will be specifically described below. 4A and 4B, one surface of adhesive sheet 71 is attached so that at least a portion thereof is linear with respect to the fixing portion of bezel 72 to display 73. Next, the other surface of adhesive sheet 71 is attached to display 73. At this time, two ends (first grip portion A and second grip portion B) in the length direction (extension direction) of adhesive sheet 71 are attached in a state where they are exposed from both ends of display 73.

[0035] <Adhesive sheet> The pressure-sensitive adhesive sheet has at least a pressure-sensitive adhesive layer, preferably a substrate layer, and, if necessary, further has other layers. It is preferable that at least one of the one surface and the other surface of the pressure-sensitive adhesive sheet is made of the pressure-sensitive adhesive layer, and it is more preferable that both the one surface and the other surface of the pressure-sensitive adhesive sheet are made of the pressure-sensitive adhesive layer.

[0036] <<Adhesive layer>> The pressure-sensitive adhesive layer contains at least a pressure-sensitive adhesive composition, and further contains other components as necessary.

[0037] -Adhesive composition- The pressure-sensitive adhesive composition contains at least the pressure-sensitive adhesive resin, and may further contain other components as needed.

[0038] The adhesive resin is not particularly limited and can be appropriately selected from known adhesives, and examples thereof include acrylic adhesive resins, rubber adhesive resins, urethane adhesive resins, and silicone adhesive resins. These may be used alone or in combination of two or more. Among these, acrylic adhesive resins are preferred as the adhesive resin.

[0039] --Acrylic adhesive resin-- The acrylic pressure-sensitive adhesive resin is not particularly limited and can be appropriately selected depending on the purpose. For example, it may contain an acrylic polymer and, if necessary, additives such as a tackifier resin and a crosslinking agent.

[0040] The acrylic polymer can be produced, for example, by polymerizing a monomer mixture containing a (meth)acrylic monomer. As the (meth)acrylic monomer, for example, alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms can be used. Specific examples of the alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0041] As the alkyl(meth)acrylate having an alkyl group of 1 to 12 carbon atoms, it is preferable to use an alkyl(meth)acrylate having an alkyl group of 4 to 12 carbon atoms, it is more preferable to use an alkyl(meth)acrylate having an alkyl group of 4 to 8 carbon atoms, and it is particularly preferable to use n-butyl acrylate in order to ensure excellent adhesion to the adherend.

[0042] The alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms is preferably used in an amount of 80% by weight to 98.5% by weight, more preferably 90% by weight to 98.5% by weight, based on the total amount of monomers used in producing the acrylic polymer.

[0043] In addition to the above-mentioned monomers, highly polar vinyl monomers can also be used as needed to produce the acrylic polymer. Examples of the highly polar vinyl monomer include (meth)acrylic monomers such as (meth)acrylic monomers having a hydroxyl group, (meth)acrylic monomers having a carboxyl group, and (meth)acrylic monomers having an amide group, as well as sulfonic acid group-containing monomers such as vinyl acetate, ethylene oxide-modified succinic acid acrylate, and 2-acrylamido-2-methylpropanesulfonic acid. These may be used alone or in combination of two or more.

[0044] Specific examples of the vinyl monomer having a hydroxyl group include (meth)acrylic monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate.

[0045] The vinyl monomer having a hydroxyl group is preferably used when the pressure-sensitive adhesive resin contains an isocyanate-based crosslinking agent. Specifically, the vinyl monomer having a hydroxyl group is preferably 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, or 6-hydroxyhexyl (meth)acrylate.

[0046] The vinyl monomer having a hydroxyl group is preferably used in an amount of 0.01% by weight to 1.0% by weight, more preferably 0.03% by weight to 0.3% by weight, based on the total amount of monomers used in producing the acrylic polymer.

[0047] Specific examples of the vinyl monomer having a carboxyl group include (meth)acrylic monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth)acrylic acid dimer, crotonic acid, and ethylene oxide-modified succinic acid acrylate. Among these, acrylic acid is preferred.

[0048] Specific examples of the vinyl having an amide group include (meth)acrylic monomers such as N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, and N,N-dimethylacrylamide.

[0049] The highly polar vinyl monomer is preferably used in a range of 1.5% by weight to 20% by weight, more preferably 1.5% by weight to 10% by weight, based on the total amount of monomers used in producing the acrylic polymer, and even more preferably in a range of 2% by weight to 8% by weight, since this allows for the formation of an adhesive layer that is well-balanced in terms of cohesion, holding power, and adhesiveness.

[0050] The method for producing the acrylic polymer is not particularly limited and can be appropriately selected from known methods depending on the purpose, and examples thereof include methods in which the monomers are polymerized by a polymerization method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, etc. Among these, the acrylic polymer is preferably produced by a solution polymerization method or a bulk polymerization method.

[0051] During the polymerization, if necessary, a peroxide-based thermal polymerization initiator such as benzoyl peroxide or lauroyl peroxide, an azo thermal polymerization initiator such as azobisisobutylnitrile, an acetophenone-based photopolymerization initiator, a benzoin ether-based photopolymerization initiator, a benzyl ketal-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, a benzoin-based photopolymerization initiator, or a benzophenone-based photopolymerization initiator can be used.

[0052] The weight-average molecular weight of the acrylic polymer obtained by the above method is preferably 300,000 to 3,000,000, and more preferably 500,000 to 2,500,000, as measured using gel permeation chromatography (GPC) and converted into standard polystyrene.

[0053] Here, the weight average molecular weight of the acrylic polymer is measured by GPC using a GPC device (HLC-8329GPC, manufactured by Tosoh Corporation) and is a value converted into standard polystyrene. The measurement conditions are as follows. [Measurement conditions] Sample concentration: 0.5 wt% (tetrahydrofuran (THF) solution) Sample injection volume: 100 μL · Eluent: THF · Flow rate: 1.0mL / min · Measurement temperature: 40℃ Column: TSKgel GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation)

[0054] The acrylic pressure-sensitive adhesive resin preferably contains a tackifier resin in order to improve adhesion to the adherend and surface adhesive strength.

[0055] The tackifier resin contained in the acrylic pressure-sensitive adhesive resin is not particularly limited and can be appropriately selected depending on the purpose, but a softening point of 30° C. to 180° C. is preferred, and 70° C. to 140° C. is more preferred for forming a pressure-sensitive adhesive layer with high adhesive performance. When a (meth)acrylate tackifier resin is used, the glass transition temperature thereof is preferably 30° C. to 200° C., and more preferably 50° C. to 160° C.

[0056] Specific examples of the tackifier resin contained in the acrylic pressure-sensitive adhesive resin include rosin-based tackifier resins, polymerized rosin-based tackifier resins, polymerized rosin ester-based tackifier resins, rosin phenol-based tackifier resins, stabilized rosin ester-based tackifier resins, disproportionated rosin ester-based tackifier resins, hydrogenated rosin ester-based tackifier resins, terpene-based tackifier resins, terpene phenol-based tackifier resins, petroleum resin-based tackifier resins, and (meth)acrylate-based tackifier resins. These may be used alone or in combination of two or more. Among these, the tackifier resin is preferably a polymerized rosin ester-based tackifier resin, a rosin phenol-based tackifier resin, a disproportionated rosin ester-based tackifier resin, a hydrogenated rosin ester-based tackifier resin, a terpene phenol-based resin, or a (meth)acrylate-based resin.

[0057] The amount of the tackifier resin used is not particularly limited and can be selected appropriately depending on the purpose, but it is preferably used in the range of 5 to 65 parts by weight per 100 parts by weight of the acrylic polymer, and more preferably in the range of 8 to 55 parts by weight, since this makes it easier to ensure adhesion to the adherend.

[0058] The acrylic adhesive resin preferably contains a crosslinking agent in order to further improve the cohesive strength of the adhesive layer.

[0059] The crosslinking agent is not particularly limited and can be appropriately selected depending on the purpose. Examples include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, metal chelate-based crosslinking agents, and aziridine-based crosslinking agents. These may be used alone or in combination of two or more. Among these, the crosslinking agent is preferably a type that is mixed after the production of the acrylic polymer to promote a crosslinking reaction, and it is more preferable to use an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent that is highly reactive with the acrylic polymer.

[0060] Examples of the isocyanate-based crosslinking agent include tolylene diisocyanate, triphenylmethane isocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and trimethylolpropane-modified tolylene diisocyanate. These may be used alone or in combination of two or more. Among these, trifunctional polyisocyanate-based compounds such as tolylene diisocyanate and its trimethylolpropane adduct, and triphenylmethane isocyanate are particularly preferred.

[0061] As an index of the degree of crosslinking, the gel fraction value obtained by measuring the insoluble portion after immersing the adhesive layer in toluene for 24 hours is used. The gel fraction of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 10 wt% to 70 wt%, more preferably 25 wt% to 65 wt%, and even more preferably 35 wt% to 60 wt% in order to obtain an adhesive layer with good cohesion and adhesiveness.

[0062] The gel fraction refers to a value measured by the following method. A pressure-sensitive adhesive composition containing the pressure-sensitive adhesive resin and, if necessary, the additives, was applied to a release sheet so that the thickness after drying was 50 μm. The coating was dried at 100°C for 3 minutes and aged at 40°C for 2 days. A 50 mm square piece was then cut out and used as a sample. The weight (G1) of the sample before immersion in toluene was measured in advance. After immersion in toluene solution for 24 hours at 23°C, the toluene-insoluble portion of the sample was separated by filtration through a 300-mesh wire screen. The weight (G2) of the residue after drying at 110°C for 1 hour was measured, and the gel fraction was calculated according to the following formula (4). The weight (G3) of the conductive fine particles in the sample was calculated from the weight (G1) of the sample and the composition of the pressure-sensitive adhesive composition. Gel fraction (wt%) = (G2 - G3) / (G1 - G3) × 100 Equation (4)

[0063] --Rubber-based adhesive resin-- The rubber-based adhesive resin is not particularly limited, and examples thereof include rubber materials that can generally be used as adhesive resins, such as synthetic rubber-based adhesive resins and natural rubber-based adhesive resins, and those that contain additives such as tackifier resins as necessary.

[0064] Examples of the rubber material include block copolymers of polyaromatic vinyl compounds and conjugated diene compounds; and styrene-based resins such as styrene-isoprene copolymers, styrene-isoprene-styrene copolymers, styrene-butadiene-styrene copolymers, styrene-ethylene-butylene copolymers, and styrene-ethylene-propylene copolymers. These may be used alone or in combination of two or more. Among these, the styrene-based resins are preferred, and using two or more styrene-based resins in combination is more preferred because it can impart excellent adhesive properties and holding power to the PSA sheet, and using a combination of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is particularly preferred.

[0065] The styrene-based resin may have a single structure, such as a linear structure, a branched structure, or a multi-branched structure, or may be a mixture of different structures. When a styrene-based resin rich in linear structures is used in the adhesive layer, it can provide the adhesive sheet with excellent adhesive performance. On the other hand, a branched or multi-branched structure in which styrene blocks are arranged at the molecular end can form a pseudo-crosslinked structure, which can provide excellent cohesive strength and therefore high holding power. For this reason, it is preferable to use a mixture of the styrene-based resins according to the required properties.

[0066] The styrene resin preferably contains 10 to 80% by weight, more preferably 12 to 60% by weight, even more preferably 15 to 40% by weight, and particularly preferably 17 to 35% by weight of the structural unit represented by the following chemical formula (1) relative to the total weight of the styrene resin, thereby achieving excellent adhesion and heat resistance.

[0067] [ka]

[0068] When the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer are used in combination as the styrene-based resin, the content of the styrene-isoprene copolymer relative to the total weight of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is preferably 0% by weight to 80% by weight, more preferably 0% by weight to 77% by weight, even more preferably 0% by weight to 75% by weight, and particularly preferably 0% by weight to 70% by weight. When the content of the styrene-isoprene copolymer is within the preferred range, the pressure-sensitive adhesive sheet can achieve both excellent adhesive performance and heat durability.

[0069] The styrene-isoprene copolymer preferably has a weight-average molecular weight, measured in terms of standard polystyrene using gel permeation chromatography (GPC), in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and even more preferably in the range of 50,000 to 300,000. Having the weight-average molecular weight of the styrene-isoprene copolymer within the preferred range ensures flowability during heating and compatibility when diluted with a solvent, which is preferable because it allows for the production of a pressure-sensitive adhesive sheet that has good workability and heat durability.

[0070] Here, the weight average molecular weight of the styrene-isoprene copolymer is measured by the GPC method using a GPC apparatus (SC-8020, manufactured by Tosoh Corporation) and is a value converted into standard polystyrene. The measurement conditions are as follows: [Measurement conditions] Sample concentration: 0.5 wt% (tetrahydrofuran solution) Sample injection volume: 100 μL Eluent: tetrahydrofuran · Flow rate: 1.0mL / min · Measurement temperature: 40℃ Column: TSKgel® GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation)

[0071] The method for producing the styrene-isoprene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods, such as a method for sequentially polymerizing a styrene block and an isoprene block by an anionic living polymerization method.

[0072] The method for producing the styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods. Examples include a method in which a styrene block and an isoprene block are sequentially polymerized by an anionic living polymerization method, and a method in which a block copolymer having a living active end is produced and then reacted with a coupling agent to produce a coupled block copolymer.

[0073] The method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods. For example, a method of mixing the styrene-isoprene copolymer produced by the above method with the styrene-isoprene-styrene copolymer can be mentioned.

[0074] As a method for producing a mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer, it is also possible to produce the mixture simultaneously in one polymerization step. In a more specific embodiment, the anionic living polymerization method involves first polymerizing styrene monomer in a polymerization solvent using an anionic polymerization initiator to form a polystyrene block having a living active end. Second, polymerizing isoprene from the living active end of the polystyrene block to obtain a styrene-isoprene diblock copolymer having a living active end. Third, reacting a portion of the styrene-isoprene diblock copolymer having the living active end with a coupling agent to form a coupled styrene-isoprene-styrene block copolymer. Fourth, using a polymerization terminator, deactivating the living active end of the remainder of the styrene-isoprene diblock copolymer having the living active end to form a styrene-isoprene diblock copolymer.

[0075] The tackifier resin contained in the rubber-based pressure-sensitive adhesive resin is not particularly limited and can be appropriately selected depending on the purpose, but it is preferable to use a tackifier resin with a softening point of 80° C. or higher, which allows the production of a pressure-sensitive adhesive sheet with excellent initial adhesion and heat durability.

[0076] The tackifier resin is preferably solid at room temperature (23°C), and specific examples thereof include petroleum resins such as C5 petroleum resins, C9 petroleum resins, C5 / C9 petroleum resins, and alicyclic petroleum resins, as well as polymerized rosin resins, terpene resins, rosin resins, terpene-phenol resins, styrene resins, coumarone-indene resins, xylene resins, and phenolic resins. These may be used alone or in combination of two or more. Among these, it is preferable to use a combination of the C5 petroleum resin and polymerized rosin resin as the tackifier resin, in order to achieve both even better initial adhesion and heat durability.

[0077] The petroleum resin is highly compatible with the structural unit represented by chemical formula (1) that constitutes the styrene-based resin, and as a result, the initial adhesive strength and heat durability of the pressure-sensitive adhesive sheet can be further improved.

[0078] Examples of the C5 petroleum resins include Escoretz 1202, Escoretz 1304, Escoretz 1401 (all manufactured by ExxonMobil Corporation), Wingtack 95 (manufactured by The Goodyear Tire & Rubber Company), Quinton K100, Quinton R100, Quinton F100 (all manufactured by Zeon Corporation), Picotack 95, and Picopal 100 (manufactured by Rika Hercules Co., Ltd.).

[0079] Examples of the C9 petroleum resins include Nippon Oil Neopolymer L-90, Nippon Oil Neopolymer 120, Nippon Oil Neopolymer 130, Nippon Oil Neopolymer 140, Nippon Oil Neopolymer 150, Nippon Oil Neopolymer 170S, Nippon Oil Neopolymer 160, Nippon Oil Neopolymer E-100, Nippon Oil Neopolymer E-130, Nippon Oil Neopolymer 130S, and Nippon Oil Neopolymer S (all manufactured by JX Nippon Oil & Energy Corporation), and Petcol (registered trademark) (manufactured by Tosoh Corporation).

[0080] As the C5 / C9 petroleum resin, a copolymer of the C5 petroleum resin and the C9 petroleum resin can be used, and examples of such products that can be used include Escoretz 2101 (manufactured by Exxon Mobil Corporation), Quinton G115 (manufactured by Zeon Corporation), and Hercotack 1149 (manufactured by Rika Hercules Co., Ltd.).

[0081] The alicyclic petroleum resin can be obtained by hydrogenating the C9 petroleum resin, and examples thereof include Escolez 5300 (manufactured by Exxon Mobil Corporation), Alcon P-100 (manufactured by Arakawa Chemical Industries, Ltd.), and Rigalite R101 (manufactured by Rika Hercules Co., Ltd.).

[0082] The amount of the tackifier resin used is not particularly limited and can be selected appropriately depending on the purpose, but is preferably used in the range of 0 to 100% by weight, more preferably 0 to 70% by weight, even more preferably 0 to 50% by weight, and particularly preferably 0 to 30% by weight, relative to the total amount of components constituting the rubber-based pressure-sensitive adhesive resin. Using the tackifier resin within this preferred range makes it easier to achieve both excellent elongation at break and heat durability of the pressure-sensitive adhesive sheet while improving the interfacial adhesion between the pressure-sensitive adhesive layer and the base layer.

[0083] The amount of the tackifier resin having a softening point of 80°C or higher used is not particularly limited and can be selected appropriately depending on the purpose, but it is preferably used in a range of 3% by weight to 100% by weight, more preferably 5% by weight to 80% by weight, relative to the total amount of the styrene-based resin, and using it in a range of 5% by weight to 80% by weight is particularly preferred in order to obtain a pressure-sensitive adhesive sheet that combines even better adhesion and excellent heat durability.

[0084] Furthermore, in order to obtain good application properties and initial adhesiveness in a constant temperature environment, a tackifier resin having a softening point of -5°C or lower can be used in combination with the tackifier resin having a softening point of 80°C or higher.

[0085] The tackifier resin having a softening point of -5°C or less is not particularly limited and can be appropriately selected from known tackifier resins according to the purpose, but it is preferable to use a tackifier resin that is liquid at room temperature.

[0086] Specific examples of the tackifier resin having a softening point of -5°C or less include process oil, polyester, and liquid rubber such as polybutene. These may be used alone or in combination of two or more. Among these, it is preferable to use polybutene as the tackifier resin having a softening point of -5°C or less in order to achieve even better initial adhesion.

[0087] The tackifier resin having a softening point of −5° C. or less is preferably used in the range of 0 to 40% by weight, more preferably 0 to 30% by weight, based on the total amount of the tackifier resin.

[0088] The tackifier resin having a softening point of -5°C or less is preferably used in an amount of 0 to 40% by weight relative to the total amount of the styrene-based resin, and more preferably in an amount of 0 to 30% by weight, since this improves the initial adhesive strength, allows for good adhesion, and also provides sufficient heat durability.

[0089] The weight ratio of the tackifier resin having a softening point of 80°C or higher to the tackifier resin having a softening point of -5°C or lower is not particularly limited and can be selected appropriately depending on the purpose. However, it is preferable to use the tackifier resin having a softening point of 80°C or higher to the tackifier resin having a softening point of -5°C or lower in a weight ratio expressed as [weight of tackifier resin having a softening point of 80°C or higher / weight of tackifier resin having a softening point of -5°C or lower] in a range of 5 to 50, and it is more preferable to use the tackifier resin in a range of 10 to 30 in order to obtain a PSA sheet that combines excellent initial adhesion and excellent holding power.

[0090] The weight ratio of the styrene resin to the tackifier resin is not particularly limited and can be selected appropriately depending on the purpose, but the weight ratio of the styrene resin to the tackifier resin, expressed as [styrene resin / tackifier resin], is preferably in the range of 0.5 to 10.0, and more preferably in the range of 0.6 to 9.0, because this improves initial adhesive strength and provides excellent thermal durability. Furthermore, the weight ratio [styrene resin / tackifier resin] is preferably greater than 1, for example, to prevent peeling due to the repulsion force of the PSA sheet when applied to a curved surface of an adherend (repulsion resistance).

[0091] -Other ingredients- The other components in the pressure-sensitive adhesive composition are not particularly limited and can be appropriately selected as long as they do not impair the properties of the pressure-sensitive adhesive sheet. Examples include polymer components other than the pressure-sensitive adhesive resin, filler particles, crosslinking agents, antioxidants, UV absorbers, bulking agents, polymerization inhibitors, surface conditioners, antistatic agents, antifoaming agents, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, plasticizers, softeners, flame retardants, and metal deactivators. These may be used alone or in combination of two or more. Among these, it is preferable to include the filler particles. The content of the other components in the pressure-sensitive adhesive layer can be appropriately selected within a range that does not impair the properties of the pressure-sensitive adhesive sheet.

[0092] Since the adhesive layer contains the filler particles, the filler particles are exposed from the adhesive layer when the adhesive sheet is stretched, thereby reducing the adhesion area between the adhesive layer and the adherend, which is advantageous in that the adhesive sheet can be easily stretched and peeled even when the stretching direction is perpendicular to the attachment surface (adhesive surface) of the adherend.

[0093] The type of the filler particles is not particularly limited and can be appropriately selected within a range that does not impair the effects of the present invention, and may be inorganic filler particles or organic filler particles. These may be used alone or in combination of two or more types.

[0094] Specific examples of the inorganic filler particles include aluminum hydroxide, magnesium hydroxide, aluminum oxide, silicon oxide, magnesium oxide, zinc oxide, titanium oxide, zirconium oxide, iron oxide, silicon carbide, boron nitride, aluminum nitride, titanium nitride, silicon nitride, titanium boride, carbon, nickel, copper, aluminum, titanium, gold, silver, zirconium hydroxide, basic magnesium carbonate, dolomite, hydrotalcite, calcium hydroxide, barium hydroxide, tin oxide, tin oxide hydrate, borax, zinc borate, zinc metaborate, barium metaborate, zinc carbonate, magnesium-calcium carbonate, calcium carbonate, barium carbonate, molybdenum oxide, Examples of suitable inorganic fillers include cerium, antimony oxide, red phosphorus, mica, clay, kaolin, talc, zeolite, wollastonite, smectite, silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, ultrafine amorphous silica, etc.), potassium titanate, magnesium sulfate, sepiolite, zonolite, aluminum borate, barium sulfate, barium titanate, zirconia, zirconia oxide, cerium, tin, indium, carbon, sulfur, cerium, cobalt, molybdenum, strontium, chromium, barium, lead, tin oxide, indium oxide, diamond, magnesium, platinum, zinc, manganese, stainless steel, and antimony pentoxide. Among these, aluminum hydroxide and nickel are preferred. The inorganic filler may be surface-treated, such as by silane coupling treatment or stearic acid treatment, in order to improve dispersibility in the adhesive resin.

[0095] Specific examples of the organic filler particles include polystyrene-based fillers, benzoguanamine-based fillers, polyethylene-based fillers, polypropylene-based fillers, silicone-based fillers, urea-formalin-based fillers, styrene / methacrylic acid copolymers, fluorine-based fillers, acrylic-based fillers, polycarbonate-based fillers, polyurethane-based fillers, polyamide-based fillers, epoxy resin-based fillers, and thermosetting resin-based hollow fillers.

[0096] The shape of the filler particles is not particularly limited and can be appropriately selected depending on the purpose, and may be regular or irregular. Specific examples of the shape of the filler particles include polygonal, cubic, elliptical, spherical, needle-like, plate-like, and scale-like shapes. The filler particles having these shapes may be used alone or in combination of two or more. Furthermore, the filler particles may be aggregates of these shapes. Among these, elliptical, spherical, and polygonal shapes are preferred as the shape of the filler particles. When the filler particles have an elliptical, spherical, polygonal, or other shape, the adhesive layer slides well on the adherend when the pressure-sensitive adhesive sheet is stretched, and stretch-peeling is easy even when the stretching direction of the pressure-sensitive adhesive sheet is 90° relative to the adhesion surface of the adherend.

[0097] The particle size distribution (D 90 / D 10 The particle size distribution (D) of the filler particles is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 2.5 to 20, and from the viewpoint of impact resistance, is more preferably 2.5 to 15, and even more preferably 2.5 to 5. 90 / D 10 ) is within the above-mentioned preferred range, the PSA sheet can be easily stretch-peeled even when the stretching direction is at 90° to the surface of the adherend, the PSA sheet is not easily torn even when the substrate is thin, and the PSA sheet is excellent in impact resistance, shear adhesive strength, and split adhesive strength. 90 / D 10 ) is less than 2.5, stretch-release properties may be impaired when the stretch direction of the pressure-sensitive adhesive sheet is at 90° to the attachment surface of the adherend, and if it exceeds 20, adhesive properties such as impact resistance, shear adhesive strength, and split adhesive strength may be impaired. The particle size distribution (D 90 / D 10 ) can be obtained by measuring the particle diameter of the filler particles using a measuring device (Microtrac) that uses a laser diffraction scattering method and converting the result into a particle size distribution.

[0098] The volume average particle size of the filler particles is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 3 μm to 25 μm, more preferably 5 μm to 20 μm, and even more preferably 5 μm to 14 μm. When the volume average particle size of the filler particles is within this preferred range, the pressure-sensitive adhesive sheet can be easily stretch-peeled even when the stretching direction is 90° to the surface to which the pressure-sensitive adhesive sheet is attached, the pressure-sensitive adhesive sheet is less likely to tear even when the base material is thin, and the impact resistance, shear adhesive strength, and split adhesive strength are excellent. On the other hand, when the volume average particle size of the filler particles is less than 3 μm, stretch-peeling may be difficult when the stretching direction of the pressure-sensitive adhesive sheet is 90° to the surface to which the pressure-sensitive adhesive sheet is attached, and when it exceeds 25 μm, adhesive properties such as impact resistance, shear adhesive strength, and split adhesive strength may be impaired. The volume average particle size of the filler particles can be measured, for example, by using a measuring device (Microtrac) that uses a laser diffraction scattering method.

[0099] The ratio of the volume average particle diameter of the filler particles to the average thickness of the adhesive layer (described later) is not particularly limited and can be appropriately selected depending on the purpose, but the ratio of the volume average particle diameter of the filler particles to the average thickness of the adhesive layer, expressed as [volume average particle diameter of filler particles / average thickness of adhesive layer], is preferably 5 / 100 or more, more preferably 5 / 100 to 95 / 100, even more preferably 10 / 100 to 75 / 100, and particularly preferably 20 / 100 to 60 / 100. When this ratio is within this preferred range, the adhesive sheet can be easily stretch-released even when the stretching direction is 90° to the adherend surface, and the adhesive sheet is less likely to tear even when the substrate thickness is thin. Furthermore, when the ratio is within the particularly preferred range, the PSA sheet can be easily stretch-released even when the stretch direction is 90° to the adherend surface, is less likely to tear even when the PSA sheet base is thin, and has the advantage of being more excellent in adhesive properties such as impact resistance, shear adhesive strength, and split adhesive strength. On the other hand, when the ratio is less than 5 / 100, stretch-release properties may be impaired when the PSA sheet is stretched at 90° to the adherend surface, and when it exceeds 95 / 100, adhesive properties such as impact resistance, shear adhesive strength, and split adhesive strength may be impaired.

[0100] The content of the filler particles in the adhesive layer is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 10 to 90 parts by weight, more preferably 15 to 50 parts by weight, and even more preferably 20 to 40 parts by weight, relative to 100 parts by weight of the adhesive resin. If the content of the filler particles relative to 100 parts by weight of the adhesive resin is less than 10 parts by weight, stretch-peeling may not be possible when the adhesive sheet is stretched at a 90° angle to the adherend surface, or the adhesive sheet may tear, resulting in the adhesive sheet not being stretched and being unable to be re-peeled. If the content of the filler particles relative to 100 parts by weight of the adhesive resin exceeds 90 parts by weight, the adhesive sheet may not be stretchable, the adhesive composition may remain on the adherend, impact resistance may be reduced, and the shear adhesive strength and split adhesive strength may be weakened. On the other hand, when the content of the filler particles is within the preferred range, the adhesive sheet can be easily stretched and peeled even when the stretching direction is 90° to the attachment surface of the adherend, and the adhesive sheet is less likely to tear even when the base material is thin, and has excellent impact resistance, shear adhesive strength, and split adhesive strength. The content of the filler particles in the pressure-sensitive adhesive layer can be appropriately adjusted when preparing the pressure-sensitive adhesive composition.

[0101] The volume ratio of the filler particles to the total volume of the adhesive layer is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 4% to 40%, more preferably 5% to 30%, even more preferably 5% to 20%, and particularly preferably 5% to 15%. If the volume ratio of the filler particles is less than 4%, stretch-peeling may not be possible when the adhesive sheet is stretched at an angle 90° to the surface of the adherend, or the adhesive sheet may tear, resulting in the adhesive sheet not being stretched and being unable to be re-peeled. If the volume ratio of the filler particles exceeds 40%, the adhesive sheet may not be stretchable, the adhesive composition may remain on the adherend, impact resistance may be reduced, and the shear adhesive strength and split adhesive strength may be weakened. On the other hand, when the volume ratio of the filler particles is within the preferred range, the adhesive sheet can be easily stretched and peeled even when the stretching direction is 90° to the attachment surface of the adherend, and the adhesive sheet is less likely to tear even when the base material is thin, and has excellent impact resistance, shear adhesive strength, and split adhesive strength.

[0102] The volume ratio of the filler particles to the adhesive layer can be calculated from the following formulas (1) to (3). adhesive resin *1 Weight A (g) / Adhesive resin *1 Density A (g / cm 3 ) = adhesive resin *1 Volume A (cm 3 )...Equation (1) Weight of filler particles B (g) / Density of filler particles B (g / cm 3 ) = Volume of filler particles B (cm 3 )...Equation (2) Filler particle volume B (cm 3 ) / (Adhesive resin *1 Volume A (cm 3 ) + volume B of filler particles (cm 3 )) × 100 = Volume ratio of filler particles (%) Equation (3) In the above formulas (1) and (3), *1 The adhesive resin represented by the formula (I) may contain other components described in paragraph

[0079] below. The density is a value measured in accordance with JIS Z 8804.

[0103] The number of the adhesive layers is not particularly limited and can be selected appropriately depending on the purpose of use, etc., and may be arranged on only one side of the adhesive sheet or on both sides, but it is preferable that they are arranged on both sides.

[0104] -Stress of adhesive layer at 25% elongation- The stress at 25% elongation of the adhesive layer is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 0.04 MPa to 0.4 MPa, and more preferably 0.05 MPa to 0.1 MPa. When the stress at 25% elongation of the adhesive layer is within this preferred range, the adhesive sheet can have suitable adhesive strength and can be relatively easily peeled off even during stretch-peeling. On the other hand, if the stress at 25% elongation of the adhesive layer is less than 0.04 MPa, the adhesive sheet may peel off when a load is applied in the shear direction of the adhesive sheet while fixing hard adherends together. If the stress exceeds 0.4 MPa, the force required to stretch the adhesive sheet when peeling it off may be excessive. The stress of the adhesive layer at 25% elongation refers to the stress value measured when the adhesive layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the longitudinal direction at a tensile speed of 300 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, and elongated by 25%.

[0105] -Breaking stress of adhesive layer- The stress at break of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.5 MPa to 2.1 MPa, and more preferably 1.0 MPa to 2.1 MPa. When the stress at break of the adhesive layer is within this preferred range, the adhesive sheet can be prevented from tearing when stretched to peel off, and the load required to stretch the adhesive sheet is not excessive, making it easy to peel off again. On the other hand, when the stress at break of the adhesive layer is less than 0.5 MPa, the adhesive sheet may tear when stretched to peel off. When the stress at break of the adhesive layer is greater than 2.1 MPa, the adhesive sheet may not be stretched sufficiently to be re-peeled. The force required to stretch and deform the adhesive sheet also depends on the thickness of the adhesive sheet. For example, when a thick adhesive sheet with a high stress at break is stretched to be re-peeled, it may not be stretched sufficiently to be re-peeled. The stress at break of the adhesive layer refers to the stress value measured when the adhesive layer is punched into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the longitudinal direction at a tensile speed of 300 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, until it breaks.

[0106] -Elongation at break of adhesive layer- The elongation at break of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 450% to 1,300%, more preferably 500% to 1,200%, and even more preferably 600% to 1,100%. When the elongation at break of the adhesive layer is within the above-mentioned preferred range, both suitable adhesiveness and removability can be achieved. The elongation at break of the adhesive layer refers to the tensile elongation measured when the adhesive layer is punched into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulled in the longitudinal direction at a tensile speed of 300 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, and when the adhesive layer breaks.

[0107] -Average thickness of adhesive layer- The average thickness of the adhesive layer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 5 μm to 150 μm, more preferably 20 μm to 120 μm, even more preferably 40 μm to 110 μm, and particularly preferably 50 μm to 100 μm. The "average thickness of the adhesive layer" refers to the average thickness of the adhesive layer on one side of the adhesive sheet. When the adhesive sheet has adhesive layers on both sides, the average thickness of the adhesive layer on one side and the average thickness of the adhesive layer on the other side may be the same or different, but are preferably the same. In this specification, the "average thickness of the adhesive layer" refers to the average thickness of a total of 25 points, measured by cutting the adhesive sheet at five points at 100 mm intervals in the lengthwise direction and at five points at 100 mm intervals in the widthwise direction on each cut surface, using a TH-104 thickness measuring instrument for paper and film (manufactured by Tester Sangyo Co., Ltd.).

[0108] -Method for forming adhesive layer- The method for forming the adhesive layer is not particularly limited and can be appropriately selected from known methods depending on the purpose, and examples thereof include methods for forming the adhesive layer on at least one surface of the base layer by methods such as heat pressing, extrusion casting, uniaxial stretching, sequential secondary stretching, simultaneous biaxial stretching, inflation, tube casting, calendaring, and solution casting. Among these, extrusion casting and solution casting are preferred.

[0109] Examples of the solution method include a method in which a solution containing the pressure-sensitive adhesive composition is directly applied to the base layer using a roll coater or the like, and a method in which the pressure-sensitive adhesive layer is formed on a release sheet and then peeled off for use.

[0110] The release sheet is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include paper such as kraft paper, glassine paper, and wood-free paper; resin films such as polyethylene, polypropylene (biaxially oriented polypropylene (OPP), uniaxially oriented polypropylene (CPP)), and polyethylene terephthalate (PET); laminated paper in which the above-mentioned paper and a resin film are laminated together; and paper in which the above-mentioned paper has been sealed with clay, polyvinyl alcohol, or the like and one or both sides of which have been subjected to a release treatment with a silicone resin or the like. These may be used alone or in combination of two or more.

[0111] <<Base material layer>> The base layer is not particularly limited and can be appropriately selected from known materials that can be used in pressure-sensitive adhesive sheets as long as the properties of the pressure-sensitive adhesive sheet are not impaired. However, it is preferable that the base layer contains the following base material materials, and may further contain other components as necessary. The substrate layer may have a single layer structure, or may have a multi-layer structure of two, three or more layers.

[0112] -Base material- Examples of materials for the substrate include styrene-based resins such as styrene-isoprene copolymer, styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene copolymer, and styrene-ethylene-propylene copolymer; polyurethane resins such as ester-based polyurethane and ether-based polyurethane; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; polycarbonate; polymethylpentene; polysulfone; polyether ether ketone; polyethersulfone; polyetherimide; polyimide film; fluororesin; nylon; and acrylic resins. These may be used alone or in combination of two or more, but it is preferable to use two or more. Among these, the styrene-based resins and the polyurethane resins are preferred because they can easily provide suitable elongation at break and stress at break, the styrene-based resins are more preferred, and it is particularly preferred to use a combination of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer.

[0113] --Styrene-based resin-- The styrene-based resin is a resin that exhibits thermoplasticity, and therefore has excellent formability in extrusion molding, injection molding, etc., and is easy to form into the substrate layer. Furthermore, the styrene-based resin is likely to have particularly excellent elongation at break among the group of resins generally called thermoplastic resins, and is therefore suitable for use as the substrate of the pressure-sensitive adhesive sheet.

[0114] Therefore, in the substrate material, the proportion of the styrene-based resin relative to the total resin components is preferably 50% to 100%, more preferably 60% to 100%, even more preferably 65% to 100%, and particularly preferably 70% to 100%. When the proportion of the styrene-based resin is within the above-mentioned preferred range, a substrate layer excellent in elongation at break and stress at break can be obtained.

[0115] The styrene-based resin may have a single structure, such as a linear structure, a branched structure, or a multi-branched structure, or may be a mixture of different structures. The styrene-based resin rich in linear structures can provide the substrate layer with excellent elongation at break. Meanwhile, a branched or multi-branched structure in which styrene blocks are arranged at the molecular end can form a pseudo-crosslinked structure and provide excellent cohesive strength. Therefore, it is preferable to use a mixture of the styrene-based resins according to the required mechanical properties.

[0116] The styrene resin preferably contains the structural unit represented by the chemical formula (1) in an amount of 13 to 60% by weight, more preferably 15 to 50% by weight, even more preferably 15 to 45% by weight, and particularly preferably 15 to 35% by weight, based on the total weight of the styrene resin. When the proportion of the structural unit represented by the chemical formula (1) in the total weight of the styrene resin is within the preferred range, the elongation at break and stress at break can be easily obtained within suitable ranges.

[0117] When the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer are used in combination as the styrene-based resin, the content of the styrene-isoprene copolymer relative to the total weight of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is preferably 0% by weight to 80% by weight, more preferably 0% by weight to 70% by weight, even more preferably 0% by weight to 50% by weight, and particularly preferably 0% by weight to 30% by weight. When the content of the styrene-isoprene copolymer is within the above-mentioned preferred range, it is possible to achieve both excellent heat durability while maintaining excellent elongation at break and stress at break.

[0118] The styrene-isoprene copolymer preferably has a weight-average molecular weight, measured in terms of standard polystyrene using gel permeation chromatography (GPC), in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and even more preferably in the range of 50,000 to 300,000. When the weight-average molecular weight of the styrene-isoprene copolymer is within the preferred range, heat flowability and compatibility when diluted with a solvent can be ensured, which is preferable because it allows the base layer to be obtained with good workability in the production process and thermal durability. The weight average molecular weight of the styrene-isoprene copolymer is measured by the GPC method in the same manner as described in the section "--Rubber-based pressure-sensitive adhesive resin--."

[0119] The method for producing the styrene-isoprene copolymer, the styrene-isoprene-styrene copolymer, and the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited and can be appropriately selected from conventionally known production methods, and examples thereof include the same methods as those described in the section "-Rubber-based pressure-sensitive adhesive resin-".

[0120] --Polyurethane resin-- The polyurethane resin is not particularly limited and can be appropriately selected depending on the purpose, but preferably has a softening point of 40° C. or higher, and more preferably has a softening point of 50° C. or higher. The upper limit of the softening point is preferably 100° C. or lower. The softening point refers to a value measured in accordance with JIS K 2207 (dry bulb method) (the same applies to softening points hereinafter).

[0121] As the polyurethane resin, a reaction product of a polyol (b1-1) and a polyisocyanate (b1-2) can be suitably used.

[0122] The polyol (b1-1) is not particularly limited and can be appropriately selected depending on the purpose. Examples include polyester polyols, polyether polyols, polycarbonate polyols, and acrylic polyols. These may be used alone or in combination of two or more. Among these, polyester polyols and polyether polyols are preferred as the polyol (b1-1) because they can provide the mechanical properties of the substrate layer. When heat resistance is required in the substrate layer, polyester polyols are preferably used, and when water resistance and biodegradability are required, polyether polyols are preferably used.

[0123] Examples of the polyester polyol include polyesters obtained by an esterification reaction between a low-molecular-weight polyol and a polycarboxylic acid, polyesters obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymer polyesters thereof.

[0124] Examples of the low-molecular-weight polyol that can be used to produce the polyester polyol include aliphatic alkylene glycols, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and 1,3-butanediol, each having a weight-average molecular weight of approximately 50 to 300, and cyclohexanedimethanol.

[0125] Examples of the polycarboxylic acid include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid; and anhydrides or esters thereof.

[0126] Examples of the polyether polyol include those obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

[0127] As the polycarbonate polyol, for example, a product obtained by reacting a carbonate ester and / or phosgene with a low-molecular-weight polyol described below can be used.

[0128] Examples of the carbonate ester include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, and diphenyl carbonate.

[0129] Examples of low-molecular-weight polyols that can be used to produce the polycarbonate polyols and that can react with the carbonate ester and / or phosgene include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, and 2,5-hexanediol. , 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcinol, bisphenol A, bisphenol F, 4,4'-biphenol, and the like.

[0130] The polyisocyanate (b1-2) is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include alicyclic polyisocyanates, aliphatic polyisocyanates, aromatic polyisocyanates, etc., and examples thereof include alicyclic polyisocyanates, etc. These may be used alone or in combination of two or more.

[0131] Examples of the alicyclic polyisocyanate include isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 2,4-methylcyclohexane diisocyanate, 2,6-methylcyclohexane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexylene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, 2,6-norbornane diisocyanate, dimer acid diisocyanate, bicycloheptane triisocyanate, etc. These may be used alone or in combination of two or more.

[0132] The method for producing the polyurethane resin (b1) by reacting the polyol (b1-1) with the polyisocyanate (b1-2) is not particularly limited and can be appropriately selected from conventionally known production methods. For example, there is a method in which the polyol (b1-1) charged in a reaction vessel is heated under normal pressure or reduced pressure to remove moisture, and then the polyisocyanate (b1-2) is supplied all at once or in portions and reacted.

[0133] The reaction of the polyol (b1-1) with the polyisocyanate (b1-2) is carried out in such a manner that the equivalent ratio (NCO / OH equivalent ratio) of the isocyanate groups (NCO) in the polyisocyanate (b1-2) to the hydroxyl groups (OH) in the polyol (b1-1) is in the range of preferably 1.0 to 20.0, more preferably 1.1 to 13.0, even more preferably 1.2 to 5.0, and particularly preferably 1.5 to 3.0.

[0134] The reaction conditions for the polyol (b1-1) and the polyisocyanate (b1-2) are not particularly limited and can be appropriately selected taking into consideration various conditions such as safety, quality, and cost. The reaction temperature is preferably 70°C to 120°C, and the reaction time is preferably 30 minutes to 5 hours.

[0135] When reacting the polyol (b1-1) with the polyisocyanate (b1-2), a catalyst such as a tertiary amine catalyst or an organometallic catalyst may be used as needed.

[0136] The reaction may be carried out in a solvent-free environment or in the presence of an organic solvent. The organic solvent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone; ether ester solvents such as methyl cellosolve acetate and butyl cellosolve acetate; aromatic hydrocarbon solvents such as toluene and xylene; and amide solvents such as dimethylformamide and dimethylacetamide. These may be used alone or in combination of two or more. The organic solvent may be removed during the production of the polyurethane resin (b1) or after the production of the polyurethane (b1) by an appropriate method such as heating under reduced pressure or drying under normal pressure.

[0137] --Other ingredients-- The other components in the substrate layer are not particularly limited and can be appropriately selected as long as they do not impair the properties of the PSA sheet, and examples thereof include tackifying resins; polymer components other than the substrate material; crosslinking agents, antioxidants, UV absorbers, fillers, polymerization inhibitors, surface conditioners, antistatic agents, antifoaming agents, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, silica beads, organic beads, and other additives; and inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, and antimony pentoxide. These may be used alone or in combination of two or more. The content of the other components in the base layer can be appropriately selected within a range that does not impair the properties of the pressure-sensitive adhesive sheet.

[0138] The tackifier resin can be used for the purposes of increasing the adhesion between the pressure-sensitive adhesive layer and the base layer in the pressure-sensitive adhesive sheet and increasing the heat resistance.

[0139] The tackifier resin is not particularly limited and can be selected appropriately depending on the purpose, but it is preferable that the softening point be 80°C or higher, more preferably 90°C or higher, even more preferably 100°C or higher, and particularly preferably 110°C or higher.

[0140] As the tackifier resin, for example, those described in the section "--Rubber-based adhesive resin--" can be used, and the same applies to preferred embodiments.

[0141] The antiaging agent is not particularly limited and can be appropriately selected from known agents depending on the purpose. Examples include phenolic antiaging agents, phosphorus-based antiaging agents (sometimes referred to as "processing stabilizers"), amine-based antiaging agents, and imidazole-based antiaging agents. These may be used alone or in combination of two or more. Among these, phenolic antiaging agents and phosphorus-based antiaging agents are preferred. Using these in combination effectively improves the heat resistance stability of the substrate material, thereby maintaining good initial adhesion and providing a pressure-sensitive adhesive sheet with even better heat durability. Note that the phosphorus-based antiaging agent may slightly discolor (yellowing) over time in a high-temperature environment. Therefore, the amount used is preferably determined appropriately, taking into consideration the balance between the initial adhesion, heat durability, and discoloration prevention.

[0142] The phenolic antioxidant can generally be a phenolic compound having a sterically hindered group, and typical examples include monophenols, bisphenols, and polyphenols. Specific examples include 2,6-di-t-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane, and n-octadecyl-3-(4'-hydroxy-3'5'-di-t-butylphenyl)propionate. These antioxidants may be used alone or in combination of two or more.

[0143] The amount of the phenolic antioxidant used is not particularly limited and can be selected appropriately depending on the purpose, but it is preferably used in the range of 0.1 to 5 parts by weight per 100 parts by weight of the substrate material, and using it in the range of 0.5 to 3 parts by weight can effectively improve the heat resistance stability of the substrate material, resulting in an adhesive sheet that maintains good initial adhesion and has even better heat durability.

[0144] -Stress of the base layer at 25% elongation- The stress at 25% elongation of the substrate layer is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 0.2 MPa to 10.0 MPa, more preferably 0.2 MPa to 5.0 MPa, even more preferably 0.2 MPa to 3.0 MPa, and particularly preferably 0.2 MPa to 2.0 MPa. When the stress at 25% elongation of the substrate layer is within this preferred range, the pressure-sensitive adhesive sheet can have suitable adhesive strength and can be relatively easily peeled off even during stretch-peel. On the other hand, if the stress at 25% elongation of the substrate layer is less than 0.2 MPa, the pressure-sensitive adhesive sheet may peel off when a load is applied in the shear direction of the pressure-sensitive adhesive sheet while fixing hard adherends together. If the stress exceeds 10.0 MPa, the force required to stretch the pressure-sensitive adhesive sheet when peeling it off may be excessive. The stress at 25% elongation of the base material layer refers to the stress value measured when the base material layer is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 6 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, and elongated by 25%.

[0145] -Break point stress of base layer- The stress at break of the substrate layer is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 1.5 MPa to 100.0 MPa, more preferably 7.0 MPa to 50.0 MPa, even more preferably 7.0 MPa to 40.0 MPa, and particularly preferably 8.0 MPa to 35.0 MPa. When the stress at break of the substrate layer is within this preferred range, the adhesive sheet can be prevented from tearing when stretched and peeled off, and the load required to stretch the adhesive sheet is not excessive, making it easy to peel off again. On the other hand, when the stress at break of the substrate layer is less than 1.5 MPa, the adhesive sheet may tear when stretched and peeled off. When the stress at break of the substrate layer is greater than 100.0 MPa, the adhesive sheet may not be stretched sufficiently when stretched and peeled off again, and peeling may not be possible. The force required to stretch and deform the adhesive sheet also depends on the thickness of the adhesive sheet. For example, if an adhesive sheet that is thick and has a high breaking stress is stretched and then tried to be re-peeled, it may not be possible to stretch it sufficiently and the sheet may not be re-peeled. The stress at break of the substrate layer refers to the stress value measured when the substrate layer is punched into a dumbbell shape with a gauge length of 20 mm and a width of 6 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, until it breaks.

[0146] -Elongation at break of base layer- The elongation at break of the base layer is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 200% to 1,300%, more preferably 400% to 1,300%, and even more preferably 700% to 1,300%. If the elongation at break of the base layer is 200% or more, even if the pressure-sensitive adhesive sheet is firmly adhered to an adherend, when the pressure-sensitive adhesive sheet is re-peeled, the stress required to stretch the sheet horizontally to vertically relative to the adherend surface is not too great, and the pressure-sensitive adhesive sheet can be easily peeled off without excessive stretching. Furthermore, if the elongation at break is 1,300% or less, when the pressure-sensitive adhesive sheet is re-peeled, the stretching distance horizontally to vertically relative to the adherend surface is not too long, allowing for work in a small space. On the other hand, if the elongation at break is less than 200%, when the pressure-sensitive adhesive sheet is peeled off, it may break when stretched horizontally to vertically relative to the adhesive surface of the adherend, and may not be able to be peeled off. If the elongation at break is more than 1,300%, when the pressure-sensitive adhesive sheet is peeled off, the stretching distance horizontally to vertically relative to the adhesive surface of the adherend becomes too long, which may result in poor workability. The elongation at break of the substrate layer refers to the tensile elongation measured when the substrate layer is punched into a dumbbell shape with a gauge length of 20 mm and a width of 6 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, and when the layer breaks.

[0147] -Average thickness of base layer- The average thickness of the base layer is not particularly limited and can be appropriately selected depending on the intended use, etc., but is preferably 10 μm to 500 μm, more preferably 10 μm to 300 μm, even more preferably 20 μm to 200 μm, and particularly preferably 20 μm to 100 μm. When the average thickness of the base layer is within the above-mentioned preferred range, the pressure-sensitive adhesive sheet can easily follow the distortion of the adherend and can easily obtain high adhesive strength, and the stress required when re-peeling the pressure-sensitive adhesive sheet having the base layer while stretching it in a direction from horizontal to vertical to the adhesion surface of the adherend is not too large, which is preferable. In this specification, the "average thickness of the base layer" refers to the average thickness of a total of 25 points, measured by cutting the base layer at five points at 100 mm intervals along the lengthwise direction, in a direction perpendicular to the lengthwise direction (sometimes referred to as the "widthwise direction"), and measuring the thickness at five points at 100 mm intervals along the widthwise direction on each cut surface using a TH-104 paper / film thickness measuring instrument (manufactured by Tester Sangyo Co., Ltd.).

[0148] -Average thickness of adhesive layer / Average thickness of base layer- The thickness ratio between the adhesive layer and the base layer is not particularly limited and can be appropriately selected depending on the purpose. However, the ratio of the average thickness of the adhesive layer to the average thickness of the base layer, expressed as [average thickness of adhesive layer / average thickness of base layer], is preferably 1 / 5 to 5 / 1, more preferably 1 / 3 to 3 / 1, and even more preferably 1 / 1 to 2 / 1. When the ratio of the average thickness of the adhesive layer to the average thickness of the base layer is within the above-mentioned preferred range, the adhesive sheet can achieve excellent adhesion and removability. On the other hand, if the ratio is greater than 5 / 1, there is a possibility that only the adhesive layer will remain on the adherend during the removal process of the adhesive sheet. Furthermore, if the ratio is less than 1 / 5, there is a concern that the adhesive layer will not be able to conform to the uneven surface of the adherend, resulting in a significant decrease in adhesive strength.

[0149] -Method for forming base layer- The method for forming the base layer is not particularly limited and can be appropriately selected from known methods depending on the mechanical strength required for the pressure-sensitive adhesive sheet, and examples include heat press, extrusion casting, uniaxial stretching, sequential secondary stretching, simultaneous biaxial stretching, inflation, tube, calendaring, and solution methods. These methods may be used alone or in combination of two or more. Among these, extrusion casting, inflation, tube, calendaring, and solution methods are preferred in terms of imparting suitable flexibility and extensibility to the base layer.

[0150] The base layer may be surface-treated in order to further improve adhesion to the adhesive layer. The surface treatment method is not particularly limited and can be appropriately selected from known methods as long as it does not impair the properties of the pressure-sensitive adhesive sheet. Examples include sandblasting, surface polishing / rubbing, corona discharge treatment, chromic acid treatment, flame treatment, hot air treatment, ozone treatment, ultraviolet irradiation treatment, and oxidation treatment.

[0151] <<Other layers>> The other layers in the pressure-sensitive adhesive sheet are not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a primer layer, an antistatic layer, a non-flammable layer, a decorative layer, a conductive layer, a heat-conductive layer, and a release layer.

[0152] - Stress of adhesive sheet at 25% elongation - The stress at 25% elongation of the pressure-sensitive adhesive sheet is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.15 MPa to 82 MPa, more preferably 0.15 MPa to 10 MPa, even more preferably 0.15 MPa to 5 MPa, and particularly preferably 0.15 MPa to 2 MPa. When the stress at 25% elongation of the pressure-sensitive adhesive sheet is 0.15 MPa to 82 MPa, the pressure-sensitive adhesive sheet can have suitable adhesive strength and can be relatively easily peeled off even during stretch-peeling. On the other hand, when the stress at 25% elongation of the pressure-sensitive adhesive sheet is less than 0.15 MPa, the pressure-sensitive adhesive sheet may peel off when a load is applied in the shear direction of the pressure-sensitive adhesive sheet while fixing hard adherends together. Furthermore, when the stress at 25% elongation of the pressure-sensitive adhesive sheet exceeds 82 MPa, the force required to stretch the pressure-sensitive adhesive sheet when peeling it off may be excessive. The stress of the pressure-sensitive adhesive sheet at 25% elongation refers to the stress value measured when the pressure-sensitive adhesive sheet is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 6 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement atmosphere conditions of 23°C and 50% RH, and elongated by 25%.

[0153] -Breaking stress of adhesive sheet- The stress at break of the pressure-sensitive adhesive sheet is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 1.5 MPa to 100.0 MPa, more preferably 5.0 MPa to 50.0 MPa, even more preferably 5.0 MPa to 40.0 MPa, and particularly preferably 5.0 MPa to 35.0 MPa. When the stress at break of the pressure-sensitive adhesive sheet is within the above-mentioned preferred range, the pressure-sensitive adhesive sheet can be prevented from tearing when stretched and peeled off, and the load required to stretch the pressure-sensitive adhesive sheet is not excessive, making it easy to peel off again. On the other hand, when the stress at break of the pressure-sensitive adhesive sheet is less than 1.5 MPa, the pressure-sensitive adhesive sheet may tear when stretched and peeled off. When the stress at break of the pressure-sensitive adhesive sheet is greater than 100.0 MPa, the pressure-sensitive adhesive sheet may not be stretched sufficiently when attempting to stretch and peel off again, and may not be re-peeled. The force required to stretch and deform the adhesive sheet also depends on the thickness of the adhesive sheet. For example, if an adhesive sheet that is thick and has a high breaking stress is stretched and then tried to be re-peeled, it may not be possible to stretch it sufficiently and the sheet may not be re-peeled. The stress at break of the pressure-sensitive adhesive sheet refers to the stress value measured when the pressure-sensitive adhesive sheet is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 6 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH, until it breaks.

[0154] -Elongation at break of adhesive sheet- The elongation at break of the pressure-sensitive adhesive sheet is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 500% to 2,000%, more preferably 600% to 1,800%, and even more preferably 800% to 1,800%. If the elongation at break of the pressure-sensitive adhesive sheet is 500% or more, even if the pressure-sensitive adhesive sheet is firmly adhered to an adherend, when the pressure-sensitive adhesive sheet is re-peeled, the stress required to stretch the pressure-sensitive adhesive sheet horizontally to vertically relative to the adherend surface is not too great, and the pressure-sensitive adhesive sheet can be easily peeled off without excessive stretching. Furthermore, if the elongation at break is 2,000% or less, when the pressure-sensitive adhesive sheet is re-peeled, the stretching distance horizontally to vertically relative to the adherend surface is not too long, allowing for work in a small space. On the other hand, if the elongation at break is less than 500%, when the pressure-sensitive adhesive sheet is peeled off, it may break when stretched horizontally to vertically relative to the adhesive surface of the adherend, and may not be able to be peeled off. If the elongation at break is more than 1,300%, when the pressure-sensitive adhesive sheet is peeled off, the stretching distance horizontally to vertically relative to the adhesive surface of the adherend becomes too long, which may result in poor workability. The elongation at break of the pressure-sensitive adhesive sheet refers to the tensile elongation measured when the pressure-sensitive adhesive sheet is punched out into a dumbbell shape with a gauge length of 20 mm and a width of 6 mm, and pulled in the longitudinal direction at a tensile speed of 500 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under measurement atmosphere conditions of 23°C and 50% RH, until it breaks.

[0155] -Impact resistance of adhesive sheets- The pressure-sensitive adhesive sheet has excellent impact resistance. The impact resistance can be confirmed, for example, by the method described in "Evaluation of Impact Resistance" in the Examples below. In the impact resistance evaluation, the height of the impact point at which the pressure-sensitive adhesive sheet peels off or breaks can be appropriately selected within a range that does not impair the effects of the present invention, but is preferably 30 cm or more, more preferably 40 cm or more, even more preferably 50 cm or more, and particularly preferably 60 cm or more. If the height is less than 30 cm, sufficient impact resistance cannot be obtained.

[0156] -180° peel adhesive strength of adhesive sheet- The 180° peel adhesive strength of the pressure-sensitive adhesive sheet is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 3 N / 20 mm to 35 N / 20 mm, more preferably 4 N / 20 mm to 30 N / 20 mm, and even more preferably 5 N / 20 mm to 25 N / 20 mm. When the 180° peel adhesive strength is within the above-mentioned preferred range, the pressure-sensitive adhesive sheet has an appropriate adhesive strength without causing peeling or slippage from the adherend, and can be easily peeled off when stretched horizontally or vertically relative to the adhesive surface of the adherend. The 180° peel adhesive strength of the pressure-sensitive adhesive sheet refers to a value measured in accordance with JIS Z 0237.

[0157] -Shear adhesive strength of adhesive sheet- The pressure-sensitive adhesive sheet is resistant to peeling even when a load is applied in the shear direction of the pressure-sensitive adhesive sheet, and has excellent shear adhesive strength. The shear direction is not particularly limited as long as it is perpendicular to the thickness direction of the pressure-sensitive adhesive sheet. The shear adhesive strength of the pressure-sensitive adhesive sheet can be appropriately selected within a range that does not impair the effects of the present invention. 2 More than 120N / 4cm is preferable. 2 More than 150N / 4cm is preferable. 2 More preferably, 200N / 4cm 2When the shear adhesive strength is within the above-mentioned preferred range, displacement can be suppressed when a stress in the shear direction is applied to an adherend fixed by the pressure-sensitive adhesive sheet. The shear adhesive strength of the pressure-sensitive adhesive sheet can be confirmed, for example, by the method described in "Measurement of Shear Adhesive Strength" in the Examples below.

[0158] - Splitting adhesive strength of adhesive sheets - The pressure-sensitive adhesive sheet is resistant to peeling even when a load is applied in the splitting direction of the pressure-sensitive adhesive sheet (sometimes referred to as the "thickness direction"), and has excellent splitting adhesive strength. The splitting adhesive strength of the pressure-sensitive adhesive sheet can be appropriately selected within a range that does not impair the effects of the present invention, but is preferably 80 N / 4 cm 2 More than 100N / 4cm is preferable. 2 More than 120N / 4cm is preferable. 2 When the splitting adhesive strength is within the above-mentioned preferred range, peeling can be suppressed when stress is applied in the splitting direction to an adherend fixed by the pressure-sensitive adhesive sheet. The splitting adhesive strength of the pressure-sensitive adhesive sheet can be confirmed, for example, by the method described in "Measurement of Splitting Adhesion Strength" in the Examples below.

[0159] -Average thickness of adhesive sheet- The average thickness of the pressure-sensitive adhesive sheet is not particularly limited and can be appropriately selected depending on the average thickness of the pressure-sensitive adhesive layer and the base layer, but is preferably 15 μm to 800 μm, more preferably 30 μm to 540 μm, even more preferably 60 μm to 320 μm, and particularly preferably 70 μm to 250 μm. In this specification, the "average thickness of the adhesive layer" refers to the average thickness of a total of 25 points, measured by cutting the adhesive sheet at five points at 100 mm intervals in the lengthwise direction and at five points at 100 mm intervals in the widthwise direction on each cut surface, using a TH-104 thickness measuring instrument for paper and film (manufactured by Tester Sangyo Co., Ltd.).

[0160] -Average width of adhesive sheet- The average width of the pressure-sensitive adhesive sheet is not particularly limited and can be appropriately selected depending on the type of electronic component. When the electronic component to be attached is a display, speaker, battery, etc., and these are fixed, the average width of the pressure-sensitive adhesive sheet can be appropriately adjusted depending on the availability of the display screen and the attachment space, but is preferably 1 mm to 50 mm, more preferably 1 mm to 25 mm, and even more preferably 0.5 mm to 10 mm. In this specification, the "average width of the adhesive sheet" refers to the average value of the widths of the adhesive sheet measured at five points at 100 mm intervals along the length using a known measuring instrument such as a straight ruler, tape measure, or convex.

[0161] <<Adhesive sheet manufacturing method>> The method for producing the pressure-sensitive adhesive sheet is not particularly limited and can be appropriately selected from known methods, but preferably includes a pressure-sensitive adhesive layer forming step, a base layer forming step, and a lamination step, and further includes other layer forming steps as necessary. The pressure-sensitive adhesive sheet can also be produced by a multilayer simultaneous formation step in which the pressure-sensitive adhesive layer forming step and the base layer forming step are performed simultaneously.

[0162] -Adhesive layer formation process- The adhesive layer forming step is not particularly limited as long as it can form the adhesive layer, and can be appropriately selected depending on the purpose. For example, it can be a method similar to the method described in the "Method for forming an adhesive layer" above, and preferred embodiments are also similar.

[0163] -Base material layer formation process- The base layer forming step is not particularly limited as long as it can form the base layer, and can be appropriately selected depending on the purpose. For example, the base layer forming step may be a method similar to the method described in the "Base layer forming method" above, and preferred embodiments are also similar.

[0164] -Lamination process- The lamination step is a step of laminating the base material layer and the adhesive layer. The method for laminating the base material layer and the adhesive layer is not particularly limited and can be appropriately selected from known methods, for example, a method of laminating the base material layer and the adhesive layer by applying pressure.

[0165] <Electronic component manufacturing method> The method for producing the electronic component is not particularly limited and can be appropriately selected depending on the purpose, but preferably includes an attachment step and a fixing step, and further includes other steps as necessary.

[0166] <<Attachment process>> The attaching step is a step of attaching one surface of the pressure-sensitive adhesive sheet to a first attachment object so that at least a portion of the surface is linear. The pressure-sensitive adhesive sheet, the first attachment object, and the attachment mode in which at least a portion of the first attachment object is linear are as described above.

[0167] <<Fixed process>> The fixing process is a process of attaching the other surface of the adhesive sheet to a second object to be attached, and attaching the adhesive sheet to the second object to be attached in a state in which at least two ends of the adhesive sheet are exposed from the second object to be attached. The second attachment target and the state in which at least two end portions are exposed from the second attachment target are as described above.

[0168] The electronic component can be quickly peeled off, is not contaminated by the adhesive after peeling, and even if it tears while being stretched and peeled from one end, it can be stretched and peeled from the other end to the end and is provided with an adhesive sheet that has suitable adhesive strength when in use.Therefore, the electronic component can be used as a wide range of electronic components, regardless of the size of the electronic component, such as large electronic devices such as flat-screen televisions, home appliances, and office equipment, and the components that make up these devices, as well as small electronic devices such as mobile electronic terminals, cameras, and personal computers, and the components that make up these devices. [Example]

[0169] The present invention will be specifically explained below by way of test examples, but the present invention is not limited to these examples in any way.

[0170] In the production of the pressure-sensitive adhesive sheets (1) to (11) in the following Production Examples 1 to 11, the following resin compositions (1) to (3) in the base layer and pressure-sensitive adhesive compositions (1) to (8) in the pressure-sensitive adhesive layer were used.

[0171] <Resin composition (1)> The resin composition (1) used was a mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer (hereinafter sometimes referred to as "SIS"), which contained 25% by weight of styrene-derived structural units represented by the following chemical formula (1), and the proportion of styrene-isoprene copolymer relative to the total amount of the resin composition (1) was 17% by weight.

[0172] [ka]

[0173] <Resin composition (2)> As the resin composition (2), an ester-based polyurethane compound (Mobilon Film MF100T, manufactured by Nisshinbo Textile Inc.) was used.

[0174] <Resin composition (3)> The resin composition (3) used was a mixture (SIS) of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer, containing 15% by weight of the styrene-derived structural unit represented by the chemical formula (1) and 12% by weight of the styrene-isoprene copolymer relative to the total amount of the resin composition (3).

[0175] (Preparation Example 1: Preparation of Pressure-Sensitive Adhesive Composition (1)) A reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, thermometer, and dropping funnel was charged with 75.94 parts by weight of n-butyl acrylate, 5 parts by weight of 2-ethylhexyl acrylate, 15 parts by weight of cyclohexyl acrylate, 4 parts by weight of acrylic acid, 0.06 parts by weight of 4-hydroxybutyl acrylate, and 200 parts by weight of ethyl acetate. The mixture was stirred and heated to 65°C while blowing in nitrogen to obtain mixture (1). Next, 4 parts by weight of a 2,2'-azobisisobutyronitrile solution (2.5% solids) previously dissolved in ethyl acetate was added to mixture (1), and the mixture was stirred and held at 65°C for 10 hours to obtain mixture (2). Next, mixture (2) was diluted with 98 parts by weight of ethyl acetate and filtered through a 200-mesh wire mesh to obtain acrylic copolymer solution (1) with a weight-average molecular weight of 1.6 million (polystyrene equivalent). Next, 100 parts by weight of the acrylic copolymer solution (1) was mixed and stirred with 5 parts by weight of a polymerized rosin ester tackifying resin (D-125, Arakawa Chemical Industries, Ltd.) and 15 parts by weight of a petroleum-based tackifying resin (FTR® 6125, Mitsui Chemicals, Inc.), and ethyl acetate was added to obtain a 31% by weight solids adhesive resin solution (1). Next, 1 part by weight of carbon black (MA220, Mitsubishi Chemical Corporation) and 1.3 parts by weight of a crosslinker (Burnoc D-40, DIC Corporation; trimethylolpropane adduct of tolylene diisocyanate, isocyanate group content 7% by weight, nonvolatile content 40% by weight) were added to 100 parts by weight of the adhesive resin solution (1), and the mixture was stirred until homogeneous. After that, the mixture was filtered through a 100-mesh wire netting to obtain a 31.1% by weight solids adhesive resin (1).

[0176] (Preparation Example 2: Preparation of Pressure-Sensitive Adhesive Composition (2)) Filler 1 (aluminum hydroxide, BW153, manufactured by Nippon Light Metal Co., Ltd., volume average particle size: 18 μm, particle size distribution (D 90 / D 10 ):12.3) was added to obtain a pressure-sensitive adhesive composition (2). The particle size distribution of the filler particles (D 90 / D 10) is a value obtained by measuring the particle diameter of the filler particles using a measuring device (Microtrac) that uses a laser diffraction scattering method and converting it into a particle size distribution.

[0177] (Preparation Example 3: Preparation of Pressure-Sensitive Adhesive Composition (3)) A pressure-sensitive adhesive composition (3) was prepared in the same manner as in Preparation Example 2, except that the type and amount of filler added in Preparation Example 2 were changed to the type and amount shown in Table 1 below. Filler 2 is nickel powder (Type 123, manufactured by Inco Corporation, volume average particle size: 11.9 μm), and the particle size distribution (D 90 / D 10 ) is 4.2.

[0178] (Preparation Example 4: Preparation of Pressure-Sensitive Adhesive Composition (4)) Pressure-sensitive adhesive composition (4) was prepared in the same manner as in Preparation Example 2, except that the type of filler in Preparation Example 2 was changed to the type shown in Table 2 below. Filler 3 is aluminum hydroxide (B303, manufactured by Nippon Light Metal Co., Ltd., volume average particle size: 23 μm), and the particle size distribution (D 90 / D 10 ) is 18.5.

[0179] (Preparation Example 5: Preparation of Pressure-Sensitive Adhesive Composition (5)) A pressure-sensitive adhesive composition (5) was prepared in the same manner as in Preparation Example 2, except that the type of filler in Preparation Example 2 was changed to the type shown in Table 2 below. Filler 4 is aluminum hydroxide (BE033, manufactured by Nippon Light Metal Co., Ltd., volume average particle size: 3 μm), and the particle size distribution (D 90 / D 10 ) is 5.8.

[0180] (Preparation Example 6: Preparation of Pressure-Sensitive Adhesive Composition (6)) A pressure-sensitive adhesive composition (6) was prepared in the same manner as in Preparation Example 2, except that the amount of filler added in Preparation Example 2 was changed to the amount shown in Table 2 below.

[0181] (Preparation Example 7: Preparation of Pressure-Sensitive Adhesive Composition (7)) A pressure-sensitive adhesive composition (7) was prepared in the same manner as in Preparation Example 2, except that the amount of filler added in Preparation Example 2 was changed to the amount shown in Table 2 below.

[0182] (Preparation Example 8: Preparation of Pressure-Sensitive Adhesive Composition (8)) In a reaction vessel equipped with a stirrer, a reflux condenser, a nitrogen inlet tube, a thermometer, and a dropping funnel, 97.97 parts by weight of n-butyl acrylate, 2.0 parts by weight of acrylic acid, 0.03 parts by weight of 4-hydroxybutyl acrylate, and 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator were dissolved in a solvent consisting of 100 parts by weight of ethyl acetate, and polymerization was carried out at 70°C for 12 hours to obtain an acrylic copolymer solution (2) having a weight-average molecular weight of 2,000,000 (polystyrene equivalent). Next, 25 parts by weight of disproportionated rosin glycerin ester (Superester A100, Arakawa Chemical Industries, Ltd.), 5 parts by weight of polymerized rosin pentaerythritol ester (Pensel D135, Arakawa Chemical Industries, Ltd.), and 20 parts by weight of styrene-based petroleum resin (FTR (registered trademark) 6100, Mitsui Chemicals, Inc.) were added to 100 parts by weight of the acrylic copolymer solution (2), and ethyl acetate was added and mixed uniformly to obtain a pressure-sensitive adhesive solution (2) with a solids content of 31% by weight. Next, 1.3 parts by weight of an isocyanate-based crosslinker (Coronate L-45, Nippon Polyurethane Industry Co., Ltd., non-volatile content 45% by weight) was added to 100 parts by weight of the pressure-sensitive adhesive solution (2), and the mixture was stirred and mixed uniformly to obtain a pressure-sensitive adhesive resin (2) with a solids content of 31.1% by weight. Next, Filler 1 (aluminum hydroxide, BW153, manufactured by Nippon Light Metal Co., Ltd., volume average particle size: 18 μm, particle size distribution (D 90 / D 10 ):12.3) was added to obtain a pressure-sensitive adhesive composition (8).

[0183] (Production Example 1: Production of adhesive sheet (1)) The pressure-sensitive adhesive composition (1) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Fujimori Kogyo Co., Ltd., the same applies below) using an applicator so that the thickness after drying would be 25 μm, and the adhesive layer was prepared by drying at 80°C for 3 minutes. Next, toluene was added to the resin composition (1) and stirred to make it uniform, and the mixture was applied to a release liner using an applicator so that the thickness after drying would be 100 μm, and then dried at 60°C for 5 minutes to produce a substrate layer. After peeling off the release liner from the base layer, the adhesive layer from which the release liner had been peeled off was attached to both sides of the base layer, and the laminated structure of the base layer and the adhesive layer was laminated by applying a pressure of 0.2 MPa to produce an adhesive sheet (1).

[0184] (Production Example 2: Production of adhesive sheet (2)) An adhesive sheet (2) was produced in the same manner as in Production Example 1, except that in the production of the adhesive sheet (1) in Production Example 1, the thickness of the base layer, the type of adhesive composition, and the thickness of the adhesive layer were changed to the conditions described in Table 1.

[0185] (Production Example 3: Production of adhesive sheet (3)) An adhesive sheet (3) was produced in the same manner as in Production Example 1, except that in the production of the adhesive sheet (1) of Production Example 1, the type of adhesive composition was changed to the conditions shown in Table 1.

[0186] (Production Example 4: Production of adhesive sheet (4)) An adhesive sheet (4) was produced in the same manner as in Production Example 1, except that in the production of the adhesive sheet (1) of Production Example 1, the type of adhesive composition was changed to the conditions shown in Table 1.

[0187] (Production Example 5: Production of adhesive sheet (5)) In the production of the adhesive sheet (1) of Production Example 1, the type of resin composition in the base layer and the type of adhesive composition were changed to the conditions described in Table 1, and an adhesive sheet (5) was produced in the same manner as in Production Example 1.

[0188] (Production Example 6: Production of adhesive sheet (6)) An adhesive sheet (6) was produced in the same manner as in Production Example 1, except that in the production of the adhesive sheet (1) of Production Example 1, the type of resin composition in the base layer, the thickness of the base layer, the type of adhesive composition, and the thickness of the adhesive layer were changed to the conditions described in Table 1.

[0189] (Production Example 7: Production of adhesive sheet (7)) An adhesive sheet (7) was produced in the same manner as in Production Example 1, except that in the production of the adhesive sheet (1) of Production Example 1, the type of adhesive composition was changed to the conditions shown in Table 2.

[0190] (Production Example 8: Production of adhesive sheet (8)) An adhesive sheet (8) was produced in the same manner as in Production Example 1, except that in the production of the adhesive sheet (1) of Production Example 1, the thickness of the base layer, the type of adhesive composition, and the thickness of the adhesive layer were changed to the conditions described in Table 2.

[0191] (Production Example 9: Production of adhesive sheet (9)) In the production of the adhesive sheet (1) of Production Example 1, the thickness of the substrate layer and the type of adhesive composition were changed to the conditions described in Table 2, and an adhesive sheet (9) was produced in the same manner as in Production Example 1.

[0192] (Production Example 10: Production of adhesive sheet (10)) In the production of the adhesive sheet (1) of Production Example 1, the thickness of the base material layer and the type of adhesive composition were changed to the conditions described in Table 2, and an adhesive sheet (10) was produced in the same manner as in Production Example 1.

[0193] (Production Example 11: Production of adhesive sheet (11)) In the production of the adhesive sheet (1) of Production Example 1, the thickness of the base layer and the type of adhesive composition were changed to the conditions described in Table 2, and an adhesive sheet (11) was produced in the same manner as in Production Example 1.

[0194] The stress at 25% elongation, stress at break, and elongation at break of the base layer in the pressure-sensitive adhesive sheets (1) to (11) of Production Examples 1 to 11; the stress at 25% elongation, stress at break, elongation at break, and filler volume ratio of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheets (1) to (11) of Production Examples 1 to 11; and the stress at 25% elongation, stress at break, elongation at break, impact resistance, 180° peel adhesive strength, shear adhesive strength, and split adhesive strength of the pressure-sensitive adhesive sheets (1) to (11) of Production Examples 1 to 11 were measured or evaluated by the following methods. The results are shown in Tables 1 and 2 below.

[0195] <<Measurement of stress at 25% elongation, stress at break, and elongation at break of adhesive sheet or base layer>> Each adhesive sheet or each base layer was punched out into a dumbbell shape with a gauge length of 20 mm and a width of 6 mm, and the stress at 25% elongation, stress at break, and elongation at break of each adhesive sheet or each base layer was measured by pulling in the longitudinal direction at a pulling rate of 500 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH.

[0196] <<Measurement of stress at 25% elongation, stress at break, and elongation at break of adhesive layer>> Each adhesive layer was punched out into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and the stress at 25% elongation, stress at break, and elongation at break of each adhesive layer were measured by pulling them in the longitudinal direction at a tensile speed of 300 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of a measurement atmosphere of 23°C and 50% RH.

[0197] <<Measurement of the volume ratio of filler particles in the adhesive layer>> The volume ratio of the filler in each adhesive layer was calculated using the following formulas (1) to (3). Weight of adhesive resin A (g) / Density of adhesive resin A (g / cm 3) = Volume A of adhesive resin (cm 3 )...Equation (1) Weight of filler particles B (g) / Density of filler particles B (g / cm 3 ) = Volume of filler particles B (cm 3 )...Equation (2) Filler particle volume B (cm 3 ) / (Volume of adhesive resin A (cm 3 ) + volume B of filler particles (cm 3 )) × 100 = Volume ratio of filler particles (%) Equation (3) The density A of the adhesive resin is 1.2 g / cm 3 , the density of the filler particles is B, and the density of aluminum hydroxide is 2.42 g / cm 3 , the density of nickel is 8.90 g / cm 3 It was calculated as:

[0198] <<Impact resistance evaluation>> Two pieces of each adhesive sheet were prepared by cutting them into a length of 20 mm and a width of 5 mm. As shown in FIG. 5A, the adhesive sheet 31 was attached parallel to an acrylic plate 32 (length 50 mm, width 50 mm, thickness 2 mm, Acrylite L, color: colorless, manufactured by Mitsubishi Rayon Co., Ltd.) with a 40 mm gap between them. Next, as shown in FIG. 5B, the acrylic plate 32 with the adhesive sheet 31 attached was attached to the center of an ABS plate 33 (length 150 mm, width 100 mm, thickness 2 mm, ToughAce R, manufactured by Sumitomo Bakelite Co., Ltd., color: natural, no grain). The laminated structure of the acrylic plate 32, the adhesive sheet 31, and the ABS plate 33 was pressed and bonded by rolling it back and forth once with a roller while applying a load of 2 kg. The laminate was then left to stand at 40°C and 50% RH for 24 hours to prepare a test specimen. As shown in FIG. 5C, a U-shaped measurement platform 34 (150 mm long, 100 mm wide, 45 mm high, and 5 mm thick, made of aluminum) was placed on the base of a DuPont impact tester (manufactured by Tester Sangyo Co., Ltd.), and the test specimen was placed on top of it with the acrylic plate 32 of the test specimen facing downward. Under conditions of 23°C and 50% RH, a stainless steel impact core (25 mm diameter, 300 g weight) 35 was dropped onto the center of the ABS plate 33 from the ABS plate 33 side. The height of the impact core 35 was changed in 10 cm increments starting from 10 cm, and the impact core 35 was dropped five times at 10-second intervals for each height. The height at which peeling or damage of the adhesive sheet on the test specimen was observed was measured. Note that specimens that did not peel or damage the adhesive sheet when dropped from a height of 30 cm or more were deemed suitable for use.

[0199] <<180° Peel Adhesion Strength Measurement>> The 180° peel adhesive strength of each PSA sheet was measured in accordance with JIS Z 0237. Specifically, each PSA sheet was cut to a length of 150 mm and a width of 20 mm, and one side of the PSA sheet was backed with a 25 μm thick PET film. Next, the other side of the PSA sheet was attached to a stainless steel plate (length 100 mm, width 30 mm, thickness 3 mm) under an atmosphere of 23°C and 50% RH. The laminated structure of the PSA sheet and the stainless steel plate was pressed and bonded by rolling it back and forth once with a roller while applying a load of 2 kg, and then left to stand for 1 hour under an atmosphere of 23°C and 50% RH to prepare a test specimen. The adhesive sheet in the test piece was stretched in the 180° direction (horizontal direction) at a tensile speed of 300 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of an atmosphere of 23°C and 50% RH, and the 180° peel adhesive strength of the adhesive sheet was measured.

[0200] <<Shear adhesive strength measurement>> Each pressure-sensitive adhesive sheet was cut into a length of 20 mm and a width of 20 mm. Under conditions of an atmosphere of 23°C and 50% RH, one side of the pressure-sensitive adhesive sheet was attached to the surface of a clean stainless steel plate A (length 100 mm, width 30 mm, thickness 3 mm) that had been hairline polished with waterproof abrasive paper (No. 360), so that the adhesive area was 20 mm x 20 mm. Next, a clean, smooth-surfaced stainless steel plate B (length 100 mm, width 30 mm, thickness 3 mm) that had been hairline polished with waterproof abrasive paper (No. 360) was attached to the side of the pressure-sensitive adhesive sheet opposite to the side to which the stainless steel plate A was attached. The laminated structure of the stainless steel plate A, the pressure-sensitive adhesive sheet, and the stainless steel plate B was pressed back and forth with a roller while applying a load of 5 kg, and then left to stand for 24 hours under conditions of an atmosphere of 23°C and 50% RH, to prepare a test specimen. Under conditions of an atmosphere of 23°C and 50% RH, with stainless steel plate A constituting the test piece fixed, stainless steel plate B constituting the test piece was stretched in the shear direction of the adhesive sheet at a tensile speed of 50 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.), and the shear adhesive strength was measured.

[0201] <<Measurement of splitting adhesive strength>> Each pressure-sensitive adhesive sheet was cut to a length of 20 mm and a width of 20 mm. Under conditions of an atmosphere of 23°C and 50% RH, one side of the pressure-sensitive adhesive sheet was attached to the surface of a clean, smooth-surfaced aluminum plate (alloy number A1050, length 50 mm, width 40 mm, thickness 3 mm) so that the attachment area was 20 mm x 20 mm. Next, a clean, smooth-surfaced aluminum plate (alloy number A1050, length 50 mm, width 40 mm, thickness 3 mm) was attached to the side of the pressure-sensitive adhesive sheet opposite to the side to which the aluminum plate was attached. The laminated structure of the two aluminum plates and the pressure-sensitive adhesive sheet was pressed back and forth once with a roller while applying a load of 5 kg, and then left to stand for 24 hours under conditions of an atmosphere of 23°C and 50% RH to prepare a test specimen. Under conditions of an atmosphere of 23°C and 50% RH, with aluminum plate A constituting the test piece fixed, aluminum plate B constituting the test piece was stretched in the split direction (thickness direction) of the adhesive sheet at a tensile speed of 50 mm / min using a Tensilon tensile testing machine (model: RTF-1210, manufactured by A&D Co., Ltd.), and the split adhesive strength was measured.

[0202] [Table 1]

[0203] [Table 2]

[0204] (Test Examples 1 to 11) Each of the pressure-sensitive adhesive sheets (1) to (11) of Production Examples 1 to 11 was cut to a width of 10 mm and a length of 60 mm. As shown in FIG. 6A, one surface 41a of the pressure-sensitive adhesive sheet 41 was attached in a straight line to a clean, smooth-surfaced aluminum plate 42 (alloy number A1050, length 50 mm, width 40 mm, thickness 3 mm). Next, the other surface 41b of the pressure-sensitive adhesive sheet 41 was attached to a clean, smooth-surfaced acrylic plate 43 (length 40 mm, width 40 mm, thickness 3 mm, Acrylite L, color: colorless, manufactured by Mitsubishi Rayon Co., Ltd.). At this time, both ends (first gripping portion A and second gripping portion B) of the pressure-sensitive adhesive sheet 41 in the longitudinal direction (extension direction) were attached with a width of 10 mm and a length of 10 mm exposed from both ends of the acrylic plate 43. Next, the laminate structure of the aluminum plate 42, adhesive sheet 41, and acrylic plate 43 was pressed together by rolling it back and forth once while applying a load of 5 kg, and then left to stand for 3 days under conditions of an atmosphere of 23°C and 50% RH. The pressure-sensitive adhesive sheets used in Test Examples 1 to 11 are as shown in Table 3 below. In Table 3 below, this application mode is indicated as "X."

[0205] (Comparative Test Examples 1 to 11) Each of the pressure-sensitive adhesive sheets (1) to (11) of Production Examples 1 to 11 was cut to a width of 10 mm and a length of 70 mm. As shown in FIG. 6C, one surface 44a of the pressure-sensitive adhesive sheet 44 was linearly attached to a clean, smooth aluminum plate 42 (alloy number A1050, length 50 mm, width 40 mm, thickness 3 mm). Next, the other surface 44b of the pressure-sensitive adhesive sheet 44 was attached to a clean, smooth acrylic plate 43 (length 40 mm, width 40 mm, thickness 3 mm, Acrylite L, color: colorless, manufactured by Mitsubishi Rayon Co., Ltd.). At this time, one end (gripping portion A') of the pressure-sensitive adhesive sheet 44 in the longitudinal direction (extension direction) was attached in a state where it was exposed from one end of the acrylic plate 43 by 10 mm in width and length. Next, the laminated structure of the aluminum plate 42, adhesive sheet 44, and acrylic plate 43 was pressed together by rolling it back and forth once while applying a load of 5 kg, and then left to stand for 3 days under conditions of an atmosphere of 23°C and 50% RH. The pressure-sensitive adhesive sheets used in Comparative Test Examples 1 to 11 are as shown in Table 3 below. In Table 3 below, this application mode is indicated as "Y."

[0206] <<Removability Evaluation 1>> The laminate structures of Test Examples 1 to 11 and Comparative Test Examples 1 to 11 were evaluated for removability in the horizontal direction by the following method. The first gripping portion A and second gripping portion B of each PSA sheet used in Test Examples 1 to 11, and the gripping portion A' of each PSA sheet used in Comparative Test Examples 1 to 11, were stretched at a 180° angle (horizontal direction) (the direction indicated by the stretching direction p in FIG. 6A or the stretching direction p in FIG. 6C ) at a stretching speed of 300 mm / min using a Tensilon tensile tester (model: RTF-1210, manufactured by A&D Co., Ltd.) under conditions of an atmosphere of 23°C and 50% RH, to conduct a stretch-peel test. The stretch-peel test was conducted 10 times in total, with five horizontal stretch-peel tests (n=5) and five vertical stretch-peel tests (n=5). In the case of application mode X in Test Examples 1 to 11, stretch-peeling was conducted from either the first gripping portion A or the second gripping portion B, followed by stretch-peeling from the other, and this was counted as one test (n=1). In this stretch-peel test, the degree of adhesive remaining on the adherend (acrylic plate) after the adhesive sheet was peeled was visually confirmed and evaluated based on the following evaluation criteria. The tearing of the adhesive sheet during stretch-peel and the ease of dismantling the aluminum plate and acrylic plate were also evaluated based on the following evaluation criteria. The evaluation results are shown in Table 3 below.

[0207] [Evaluation criteria for adhesive residue] ○: No adhesive residue ×: adhesive residue was found In the evaluation criteria for residual adhesive, "◯" indicates that there is no problem in use.

[0208] As an example of the degree of adhesive residue in the stretch-peel test, FIG. 7A shows the appearance of the acrylic plate after horizontal stretch-peel in Test Example 1, and FIG. 7B shows the appearance of the acrylic plate after horizontal stretch-peel in Comparative Test Example 1. In FIG. 7A, "410" indicates the location where the adhesive sheet was attached, and "p" indicates the stretch direction of the adhesive sheet. In FIG. 7B, "440" indicates the location where the adhesive sheet was attached, and "p" indicates the stretch direction of the adhesive sheet. As is clear from these results, when the sheet was attached using attachment mode X, no adhesive residue remained, whereas when the sheet was attached using attachment mode Y, clear residual adhesive sheet residue was observed.

[0209] [Evaluation criteria for shredded pieces] ◎: The number of times it broke was 0 ○: The number of times it broke was 1 to 2 times △: The number of times it broke was 3 to 4 times ×: The number of times it was torn was 5 In the evaluation criteria for tearing, "◯" and "◎" indicate that there is no problem in use.

[0210] [Evaluation criteria for dismantling] ◎: The number of times it was dismantled was 5 ○: The number of times the item was dismantled was 3 to 4 times. △: The number of times it was possible to dismantle it was 1 to 2 times. ×: The number of times the item was dismantled was 5. In the evaluation criteria for dismantling ease, "◯" and "◎" indicate that there is no problem in use.

[0211] [Table 3]

[0212] The results in Table 3 above show that when the application mode in Test Examples 1 to 11 was X, there was no contamination by the adhesive after peeling, and even if the tape tore during stretch-peeling from one end (first gripping portion), it could be stretch-peeled from the other end (second gripping portion) and peeled all the way to the end. On the other hand, when the application mode in Comparative Test Examples 1 to 11 was Y, even if stretch-peeling was possible, adhesive remained on the adherend, and if the tape tore during stretch-peeling from one end, it was not possible to peel all the way to the end, and the aluminum plate and acrylic plate could not be disassembled.

[0213] <<Removability Evaluation 2>> The laminate structures of Test Examples 1 to 11 were evaluated for removability in the vertical direction by the following method. In the above <<Removability Evaluation 1>>, the stretching conditions of the first gripping portion A and the second gripping portion B of each of the PSA sheets used in Test Examples 1 to 11 were changed from a 180° direction (horizontal direction) (the direction indicated by the stretching direction p in FIG. 6A) to a 90° direction (vertical direction) relative to the adhesive surface of the PSA sheet (the direction indicated by the stretching direction p in FIG. 6B), and the degree of adhesive residue on the adherend (acrylic plate) after the PSA sheet was peeled, tearing of the PSA sheet during stretch peeling, and dismantling ability of the aluminum plate and the acrylic plate were evaluated in the same manner as in the above <<Removability Evaluation 1>>. The evaluation results are shown in Table 4 below.

[0214] [Table 4]

[0215] The results in Table 4 above show that the adhesive sheets (2) to (11) of test examples 2 to 11 did not cause contamination by the adhesive after peeling, even when stretched and peeled in a direction 90° (perpendicular) to the adhesive surface of the adhesive sheet.

[0216] The present invention includes, for example, the following aspects. <1> The electronic component is characterized by comprising an adhesive sheet having one surface attached to a first attachment object so that at least a portion of the surface is linear, and the other surface attached to a second attachment object, with at least two ends exposed from the second attachment object. <2> At least one of the first and second attachment objects is a recovered part. <1> The electronic component is described in the above. <3> The recovered parts are at least one of display glass and batteries. <1> from <2> The electronic component is any one of the above. <4> When the width of the adhesive area of the adhesive sheet on the electronic component is X (cm) and the length of the adhesive area is Y (cm), the ratio (X / Y) of the width of the adhesive area to the length of the adhesive area is 1 / 100,000 to 1 / 1. <1> from <3> The electronic component is any one of the above. [Industrial Applicability]

[0217] The electronic component can be quickly peeled off, is not contaminated by the adhesive after peeling, and even if it tears while being stretched and peeled from one end, it can be stretched and peeled from the other end to the end and is provided with an adhesive sheet that has suitable adhesive strength when in use.Therefore, the electronic component can be used as a wide range of electronic components, regardless of the size of the electronic component, such as large electronic devices such as flat-screen televisions, home appliances, and office equipment, and the components that make up these devices, as well as small electronic devices such as mobile electronic terminals, cameras, and personal computers, and the components that make up these devices. [Explanation of symbols]

[0218] 1 Grip Tab 2 Adhesion area 3 End 4 First adhesive area 5 Second adhesive area 6 Third adhesive area 7 Tip 21 Adhesive sheet 21a One surface of the adhesive sheet 21 21b: the other surface of the adhesive sheet 21 22 First attachment target 23 Secondary Attachment 31 Adhesive Sheet 32 Acrylic plate 33 ABS board 34 U-shaped measuring table 35 Strike core 41 Adhesive Sheet 41a One surface of the adhesive sheet 41 41b: the other surface of the adhesive sheet 41 42 First attachment target 43 Secondary Attachment 44 adhesive sheet 61 Adhesive Sheet 61a One surface of the adhesive sheet 61 61b: the other surface of the adhesive sheet 61 62 Back Chassis 63 Battery 71 Adhesive Sheet 71a One surface of adhesive sheet 71 71b: the other surface of the adhesive sheet 71 72 bezel 73 Display 410 Where the adhesive sheet was attached 440 Where the adhesive sheet was attached A First gripping part B Second gripping part C. Third gripping part D Fourth gripping part A' Gripping part p stretching direction

Claims

1. a stretch-releasable adhesive sheet having one surface attached to a first object so that at least a portion of the surface is linear, and the other surface attached to a second object, with at least two ends exposed from the second object; An electronic component characterized in that the 180° peel adhesive strength of the pressure-sensitive adhesive sheet is 15.5-35 N / 20 mm.

2. The electronic component according to claim 1 , wherein at least one of the first and second attachment targets is a recovered component.

3. 3. The electronic component according to claim 2, wherein the recovered component is at least one of a display glass and a battery.

4. The electronic component according to any one of claims 1 to 3, wherein when the width of the adhesive area of the adhesive sheet is X (cm) and the length of the adhesive area is Y (cm), the ratio (X / Y) of the width of the adhesive area to the length of the adhesive area is 1 / 100,000 to 1 / 1.

5. The electronic component according to any one of claims 1 to 4, wherein the adhesive sheet has at least an adhesive layer containing filler particles.

6. The adhesive sheet has a splitting adhesive strength of 80 N / 4 cm ２ The electronic component according to any one of claims 1 to 5.

7. The method for disassembling electronic components according to any one of claims 1 to 6, A method for dismantling electronic components, characterized in that the first and second attachment objects are disassembled by gripping at least one end of the adhesive sheet exposed from the second attachment object and stretching and peeling the adhesive sheet.

8. Stretching and peeling the adhesive sheet by gripping and simultaneously stretching the multiple ends of the adhesive sheet exposed from the second attachment target, or 8. The method for dismantling electronic components according to claim 7, characterized in that the first and second attachment objects are dismantled by: gripping and stretching any one of the plurality of ends of the adhesive sheet exposed from the second attachment object to peel off a portion of the adhesive sheet, and then gripping and stretching at least one of the ends other than the end that was previously stretched to peel off the remaining portion.

9. Shear adhesive strength of the pressure-sensitive adhesive sheet: 500 N / 4 cm ２ The electronic component according to any one of claims 1 to 6.

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