CN113330551A

CN113330551A - Electronic component

Info

Publication number: CN113330551A
Application number: CN202080010240.3A
Authority: CN
Inventors: 渡边大亮; 山上晃
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2019-02-04
Filing date: 2020-01-23
Publication date: 2021-08-31
Also published as: WO2020162204A1; JP2022088491A; JP2023181243A; JPWO2020162204A1; JP7056768B2

Abstract

Provided is an electronic component which is provided with an adhesive sheet that can be peeled off quickly, is free from contamination by the adhesive after peeling, can be peeled off by stretching from one end to the end even if it breaks during the peeling off by stretching from the other end, and has an appropriate adhesive force during use. The present invention relates to an electronic component including an adhesive sheet, one surface of which is bonded to a first bonding object such that at least a part of the adhesive sheet is linear, the other surface of which is bonded to a second bonding object, and the adhesive sheet is bonded to the second bonding object in a state where at least 2 ends of the adhesive sheet are exposed from the second bonding object.

Description

Electronic component

Technical Field

The present invention relates to an electronic component.

Background

In the case of fixing components constituting an electronic device, for example, an adhesive sheet (also referred to as an "adhesive tape") is widely used as a bonding means having excellent workability and high adhesion reliability. Specifically, an adhesive tape is used for component fixing purposes in various industrial fields such as fixing of metal plates constituting relatively large electronic devices such as thin televisions, home electric appliances, and OA equipment, fixing of an exterior member and a housing, fixing of a rigid member such as an exterior member and a battery to relatively small electronic devices such as portable electronic terminals, cameras, and personal computers, temporary fixing of the component, and labeling purposes for displaying product information.

In recent years, in the above-described industrial fields, for the purpose of resource saving and the like, there have been increasing cases where reusable or reusable components used in products are decomposed after use and reused or reused from the viewpoint of global environmental protection. In this case, when the adhesive tape is used, the adhesive tape attached to the member needs to be peeled, but the adhesive tape is generally large in adhesive force and attached to a plurality of places in the product, and therefore, the work of peeling them is accompanied by considerable labor. Therefore, in the case of recycling or reuse, it is required to reduce the work cost by easy peeling and removal.

As an adhesive tape that can be easily peeled and removed, there has been proposed an adhesive tape including an adhesive portion and a projecting piece portion that is attached so as to be capable of being sandwiched by protruding from one of an extended portion of a first adherend and an extended portion of a second adherend, and that is capable of being peeled by being stretched in a direction substantially parallel to an adhesive surface by sandwiching the projecting piece portion (see patent document 1). However, in the case where the tab portion (gripping portion) for stretch-releasing is present only at one end as in the pressure-sensitive adhesive tape proposed in the above, there is a problem that the pressure-sensitive adhesive remains on the adherend and is contaminated after the pressure-sensitive adhesive tape is released on the adhesive surface of the pressure-sensitive adhesive tape opposite to the side having the tab portion (that is, the surface to which the pressure-sensitive adhesive tape is adhered for the longest time at the time of release). In addition, there are also problems as follows: if the tab portion at one end breaks during the elongation and peeling, the tab portion cannot be further peeled off, and the reusable or reusable member cannot be further disassembled.

In contrast, an adhesive film as shown in fig. 1 is proposed, which includes an adhesive region (2), the adhesive region (2) being adjacent to a handle tab (1) located at 1 distal end portion of the adhesive film sheet and extending toward the other distal end portion (3), wherein the adhesive region (2) includes, in order from the handle tab (1) toward the other distal end portion (3) of the adhesive film sheet: 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 sharply decreases toward the distal end portion (3); and a third bonding region (6) that forms a tip portion (3) and terminates at 1 or more tip portions (7) in the direction toward the tip portion (3) (see patent document 2). However, the shape of the adhesive film proposed in this case has a problem that the adhesion area becomes small, the adhesion area cannot be effectively used, and the adhesive force becomes weak. In the above-mentioned electronic device, the peeling of the components constituting the electronic device is a big problem in use, and in order to be reusable or reusable, it is necessary to maintain the adhesive force before the electronic component is recovered.

Therefore, it is strongly desired to provide an electronic component having an adhesive sheet which can be peeled off quickly, is free from contamination by the adhesive after peeling, can be peeled off by elongation from one end portion to the end even if it is broken in the middle of peeling off by elongation from the other end portion, and has an appropriate adhesive force in use.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-124289

Patent document 2: specification of U.S. Pat. No. 6680096

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above-described various problems of the related art, and has an object to achieve the following. That is, an object of the present invention is to provide an electronic component including an adhesive sheet which can be peeled off quickly, is free from contamination by the adhesive after peeling, can be peeled off by elongation from one end portion to the end even if it is broken in the middle of peeling off by elongation from the other end portion, and has an appropriate adhesive force in use.

Means for solving the problems

The means for solving the above problems are as follows.

That is, the electronic component is characterized by comprising an adhesive sheet, one surface of which is bonded to a first bonding object so that at least a part of the adhesive sheet is linear, the other surface of which is bonded to a second bonding object, and the adhesive sheet is bonded to the second bonding object in a state where at least 2 ends of the adhesive sheet are exposed from the second bonding object.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can solve the above-described problems of the related art, and achieves the above-described object, and can provide an electronic component including an adhesive sheet that can be peeled off quickly, is free from contamination by the adhesive after peeling, can be peeled off by elongation from one end to the end even if it is broken during the peeling off by elongation from the other end, and has an appropriate adhesive force when used.

Drawings

Fig. 1 is a diagram showing a conventional adhesive film.

Fig. 2A is a schematic explanatory view (plan view) showing one embodiment of the electronic component of the present invention.

Fig. 2B is a schematic explanatory view (sectional view) showing one embodiment of the electronic component of the present invention.

Fig. 2C is a schematic explanatory view (sectional view) showing another embodiment of the electronic component of the present invention.

Fig. 2D is a schematic explanatory view (plan view) showing another embodiment of the electronic component of the present invention.

Fig. 2E is a schematic explanatory view (plan view) showing another embodiment of the electronic component of the present invention.

Fig. 2F is a schematic explanatory view (plan view) showing another embodiment of the electronic component of the present invention.

Fig. 2G is a schematic explanatory view (plan view) showing another embodiment of the electronic component of the present invention.

Fig. 3A is a schematic explanatory view (sectional view) of a case where the electronic component of the present invention is a battery.

Fig. 3B is a schematic explanatory view (plan view) of a case where the electronic component of the present invention is a battery.

Fig. 3C is a schematic explanatory view (sectional view) showing another embodiment of the present invention in the case where the electronic component is a battery.

Fig. 4A is a schematic explanatory view (cross-sectional view) of a case where the electronic component of the present invention is a display of a television.

Fig. 4B is a schematic explanatory diagram (top view) of a case where the electronic component of the present invention is a display of a television.

Fig. 5A is a schematic explanatory view (cross-sectional view) of a method of attaching the adhesive sheet 31 to the acrylic plate 32 in the evaluation of impact resistance in the examples.

FIG. 5B is a schematic explanatory view (plan view) of a test piece produced in the evaluation of impact resistance in examples.

FIG. 5C is a schematic explanatory view (cross-sectional view) of the method of setting the test piece on the measuring table shaped as コ letter when the impact resistance is evaluated in the examples.

Fig. 6A is a schematic explanatory view (cross-sectional view) of the sticking method X and the tensile direction (horizontal direction) in the tensile peel test in test examples 1 to 11.

Fig. 6B is a schematic explanatory view (cross-sectional view) of the sticking method X and the tensile direction (vertical direction) in the tensile peel test in test examples 1 to 11.

Fig. 6C is a schematic explanatory view (cross-sectional view) of the sticking method Y and the tensile direction (horizontal direction) in the tensile peel test in comparative test examples 1 to 11.

Fig. 7A is a view showing the appearance of the acrylic sheet after the horizontal tensile peeling in test example 1 (sticking method X).

Fig. 7B is a view showing the appearance of the acrylic sheet after the horizontal tensile peeling in test example 1 (bonding method Y).

Detailed Description

(electronic parts)

The electronic component includes an adhesive sheet having one surface bonded to a first object to be bonded so that at least a part of the adhesive sheet is linear, and the other surface bonded to a second object to be bonded, and bonded to the second object to be bonded in a state where at least 2 ends of the adhesive sheet are exposed from the second object to be bonded. In the present specification, the first attachment object or the second attachment object may be collectively referred to as an "adherend".

In the present specification, the electronic component includes not only various components such as a metal plate, an exterior, a housing, and a battery that constitute the electronic device, but also an electronic device itself such as a television, a home electric appliance, an OA device, a portable electronic terminal, a camera, and a personal computer.

Hereinafter, the configuration of the electronic component will be specifically described with reference to the drawings, and the present invention is not limited to these embodiments.

As shown in fig. 2A and 2B, in the electronic component, one surface 21a of the adhesive sheet 21 is stuck to one surface of a first sticking object 22 constituting the electronic component so that at least a part thereof is linear. Next, the other surface 21b of the adhesive sheet 21 is attached to a second attachment object 23 constituting the electronic component. At this time, 2 ends of the adhesive sheet 21 in the longitudinal direction are attached in a state of being exposed from the second object to be attached 23. Thereby, at least a part of each end of the adhesive sheet 21 exposed from the second application object 23 functions as a grip. Fig. 2C is a diagram showing another embodiment of the electronic component.

In fig. 2A to 2C, an example is shown in which the adhesive sheet is attached to the first attachment object so as to be linear and the end of the adhesive sheet is 2, but the adhesive sheet may be attached to the first attachment object so that at least a part of one surface of the adhesive sheet is linear, and the adhesive sheet may be attached to the first attachment object in a shape branched at a middle point or a shape curved at a middle point as shown in fig. 2D to 2G. Therefore, the number of the end portions (gripping portions) of the adhesive sheet is not particularly limited, and may be appropriately selected according to the shape of the adhesive sheet to be attached, and the like. In this case, the number of the end portions of the adhesive sheet exposed from the second object to be bonded is not particularly limited as long as it is at least 2, and may be appropriately selected according to the purpose, and preferably all the end portions are exposed from the second object to be bonded. Hereinafter, the respective ends of the adhesive sheet 21 exposed from the second object of attachment 23 may be referred to as a first grip portion a, a second grip portion B, a third grip portion C, a fourth grip portion D, and the like.

In fig. 2A to 2G, an example is shown in which the respective grasping portions a to D are not exposed from the first sticking object 22, but there is no particular limitation as long as at least 2 of the respective grasping portions a to D are exposed from the second sticking object 23, and at least any one of the respective grasping portions a to D may be exposed from the first sticking object 22.

< grip part >

The gripping portion may be directly arranged on the first adhesion object 22 as shown in fig. 2A and 2B, or may be arranged on a side surface (surface in the thickness direction) of the second adhesion object 23 (the first gripping portion a and the second gripping portion B in fig. 2A to 2C) as shown in fig. 2C, and although not shown, may be arranged so as to be in contact with another element in the electronic component adjacent to at least one of the first adhesion object 22 and the second adhesion object 23.

The holding part is an end of the adhesive sheet, and the number of adhesive layers in an adhesive surface with at least one of the first and second objects may be the same as or different from the number of adhesive layers in the holding part. For example, in the case where the adhesive sheet has adhesive layers on both sides thereof, the adhesive layer in at least one of the plurality of holding portions may be disposed on only one side. The number of the adhesive layers in the plurality of grip portions may be the same or different.

The holding portion may be formed by processing at least a part of an end portion of the adhesive sheet. The processing is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include processing for removing the adhesive layer in the adhesive sheet, processing for disposing a release sheet on the surface of the adhesive layer in the adhesive sheet, and processing for modifying the adhesive layer in the adhesive sheet to be non-adhesive by a known means such as a release agent.

The release sheet is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include paper such as kraft paper, cellophane paper, and forest paper; resin films such as polyethylene, polypropylene (biaxially oriented polypropylene (OPP), uniaxially oriented polypropylene (CPP)), polyethylene terephthalate (PET), and the like; a laminated paper obtained by laminating the paper and a resin film, a paper obtained by subjecting the paper to a gap-filling treatment with clay, polyvinyl alcohol, or the like, and a peeling treatment with silicone resin or the like on one side or both sides thereof, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The length of the grip portion is not particularly limited as long as it is stretchable, and may be appropriately selected according to the distance between the electronic component and the like adjacent to the first attachment target and the second attachment target, and the like, and is preferably 5mm or more, more preferably 10mm or more, and still more preferably 15mm or more. The upper limit of the length is not particularly limited, and may be appropriately selected according to the size of the electronic component, and is preferably 20mm or less.

The length of each gripping part may be the same or different.

The width of the holding portion is not particularly limited, and may be appropriately selected according to the width of the adhesive sheet and the like.

< stretching direction p >

The adhesive sheet 21 in the electronic component described above is easily peeled by being stretched in the stretching direction p shown in fig. 2B and 2C. Fig. 2B shows a mode in which the stretching direction p of the adhesive sheet 21 is in the horizontal direction (180 ° direction) with respect to the adhesion surface with the first adhesion object 22 and the second adhesion object 23, and fig. 2C shows a mode in which the stretching direction p of the adhesive sheet 21 is in the vertical direction (90 ° direction) with respect to the adhesion surface with the first adhesion object 22 and the second adhesion object 23, and the angle of the stretching direction p with respect to the adhesion surface with the first adhesion object 22 and the second adhesion object 23 is not particularly limited and may be appropriately selected in accordance with the surrounding environment of the electronic component or the like.

The adhesive sheet in the electronic component may be peeled by simultaneously pulling the plurality of holding portions, or may be peeled by pulling one of the plurality of holding portions to peel a part thereof and then pulling the other to peel the remaining part thereof. Further, since at least 2 ends of the adhesive sheet in the electronic component are exposed from the second object to be bonded, even when the adhesive sheet is broken during the stretch peeling from one end (first holding part), the adhesive sheet can be peeled from the other end (second holding part) by stretching and peeling to the end, which is advantageous in that it is possible to prevent the adhesive sheet from being peeled off from the second holding part.

The removability of the adhesive sheet in the electronic component can be confirmed by, for example, a method described in "evaluation of removability 1" in test examples described later. In the evaluation of the above removability, the removability was excellent in that the grip portion at one end could be peeled off by elongation to the end even if the grip portion at the other end broke in the middle of the peeling by elongation without staining with the adhesive after the peeling.

< width of attachment area/length of attachment area (X/Y) >

When the width of the bonding area of the pressure-sensitive adhesive sheet in the electronic component is X (cm) and the length of the bonding area is Y (cm), the ratio of the width of the bonding area to the length of the bonding area represented by [ X/Y ] is not particularly limited and may be appropriately selected according to the purpose, and is preferably 1/1 to 1/100000, more preferably 1/1 to 1/10000, and still more preferably 1/1 to 1/1000. If the ratio of the sticking areas is less than 1/1, the adhesive strength may be insufficient, and if it exceeds 1/100000, the adhesive sheet may be broken at the time of stretch peeling or the adhesive may be contaminated after peeling.

< first pasting object or second pasting object >

The first attachment object and the second attachment object may be the same member or different members. Further, the first attachment object may be exchanged with the second attachment object.

The material of the first and second objects to be attached is not particularly limited, and may be appropriately selected according to the kind of the electronic component, and examples thereof include metal, alloy, glass, plastic, and ceramic. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

Specific examples of the first adhesion object include a rear chassis, a frame, a metal plate, a frame, and a heat sink.

Specific examples of the second object to be attached include a glass for display, a battery, a heat dissipating member such as a heat sink, a speaker, a lens for camera, and the like.

Preferably, the first attachment object and the second attachment object are recovery members. The recovery member is not particularly limited as long as it can be reused or reused, and may be appropriately selected according to the purpose, and examples thereof include a recovery member when a trouble occurs in the production process of an electronic component, a recovery member when discarded, and the like. The pressure-sensitive adhesive sheet in the electronic component is advantageously capable of being rapidly peeled off, free from contamination by the pressure-sensitive adhesive after peeling, and capable of being peeled off by elongation from the other end portion to the end even if the pressure-sensitive adhesive sheet is broken in the middle of the peeling by elongation from the one end portion, so that at least either one of the first attachment object and the second attachment object as the recovery member can be rapidly recovered, and free from contamination when at least either one of the first attachment object and the second attachment object is reused or reused.

Hereinafter, more specific embodiments of the electronic component will be described with reference to the drawings, and the present invention is not limited to these embodiments.

Hereinafter, an embodiment in which the electronic component is a small component such as a battery will be specifically described.

As shown in fig. 3A and 3B, one surface 61a of the adhesive sheet 61 is attached to the fixing portion of the battery 63 of the rear chassis 62 so that at least a part thereof is linear. Next, the other surface 61b of the adhesive sheet 61 is attached to the battery 63. At this time, 2 ends (the first holding portion a and the second holding portion B) in the longitudinal direction (extending direction) of the adhesive sheet 61 are attached in a state of being exposed from both ends of the battery 63. The method of attaching the first holding portion a and the second holding portion B to the adhesive sheet 61 may be the method shown in fig. 3C.

In the following, an embodiment in which the electronic component is a large-sized component such as a television display will be specifically described.

As shown in fig. 4A and 4B, one surface of the adhesive sheet 71 is attached to a fixed portion of the display 73 of the bezel 72 so that at least a part thereof is linear. Next, the other surface of the adhesive sheet 71 is attached to the display 73. At this time, 2 ends (the first holding portion a and the second holding portion B) in the longitudinal direction (extending direction) of the adhesive sheet 71 are attached in a state of being exposed from both ends of the display 73.

< pressure-sensitive adhesive sheet >

The pressure-sensitive adhesive sheet has at least a pressure-sensitive adhesive layer, preferably a base layer, and further has another layer as required.

Preferably, at least one of the one surface and the other surface of the adhesive sheet includes the adhesive layer, and more preferably, both the one surface and the other surface of the adhesive sheet include the adhesive layer.

Adhesive layer

The adhesive layer contains at least an adhesive composition and, if necessary, further contains other components.

Adhesive composition

The adhesive composition contains at least the adhesive resin and, if necessary, other components.

The binder resin is not particularly limited, and may be appropriately selected from known ones, and examples thereof include acrylic binder resins, rubber binder resins, urethane binder resins, and silicone binder resins. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these, the binder resin is preferably an acrylic binder resin.

-acrylic binder resin-

The acrylic adhesive resin is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include resins containing an acrylic polymer and, if necessary, additives such as a tackifier resin and a crosslinking agent.

The acrylic polymer can be produced, for example, by polymerizing a monomer mixture containing a (meth) acrylic monomer.

Examples of the (meth) acrylic monomer include alkyl (meth) acrylates having an alkyl group having 1 to 12 carbon atoms.

Specific examples of the alkyl (meth) acrylate having an alkyl group of 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, and 2-ethylhexyl (meth) acrylate. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The alkyl (meth) acrylate having an alkyl group with 1 to 12 carbon atoms is preferably an alkyl (meth) acrylate having an alkyl group with 4 to 12 carbon atoms, more preferably an alkyl (meth) acrylate having an alkyl group with 4 to 8 carbon atoms, and particularly preferably n-butyl acrylate in order to ensure excellent adhesion to an adherend.

The alkyl (meth) acrylate having an alkyl group having 1 to 12 carbon atoms is preferably used in a range of 80 to 98.5 wt%, more preferably 90 to 98.5 wt%, based on the total amount of monomers used for producing the acrylic polymer.

As the monomer that can be used in the production of the acrylic polymer, a highly polar vinyl monomer may be used as necessary in addition to the above-mentioned monomers.

Examples of the high-polarity vinyl monomer include (meth) acrylic monomers having a hydroxyl group, a carboxyl group, and an amido group, and 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 in 1 kind, or may be used in combination of 2 or more kinds.

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.

The vinyl monomer having a hydroxyl group is preferably used when a binder resin containing an isocyanate-based crosslinking agent is used as the binder resin. Specifically, as the vinyl monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate are preferably used.

The hydroxyl group-containing vinyl monomer is used preferably in a range of 0.01 to 1.0 wt%, more preferably in a range of 0.03 to 0.3 wt%, based on the total amount of monomers used for producing the acrylic polymer.

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 them, acrylic acid is preferred.

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

The highly polar vinyl monomer is preferably used in a range of 1.5 to 20 wt%, more preferably 1.5 to 10 wt%, and even more preferably 2 to 8 wt%, based on the total amount of monomers used for producing the acrylic polymer, since an adhesive layer having a balance among cohesive force, holding force, and adhesiveness can be formed.

The method for producing the acrylic polymer is not particularly limited, and may be appropriately selected from known methods according to the purpose, and examples thereof include a method of polymerizing the monomer by a polymerization method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method. Among them, the acrylic polymer is preferably produced by a solution polymerization method or a bulk polymerization method.

In the polymerization, a peroxide-based thermal polymerization initiator such as benzoyl peroxide or lauroyl peroxide, an azo-based thermal polymerization initiator such as azobisisobutyronitrile, an acetophenone-based photopolymerization initiator, a benzoin ether-based photopolymerization initiator, a benzoin ketal-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, or the like may be used as necessary.

The weight average molecular weight of the acrylic polymer obtained by the above method is preferably 30 to 300 ten thousand, more preferably 50 to 250 ten thousand, as measured by Gel Permeation Chromatography (GPC) in terms of standard polystyrene.

The weight average molecular weight of the acrylic polymer by GPC was measured as a standard polystyrene value by GPC (HLC-8329GPC, available from Tosoh corporation), and the measurement conditions were as follows.

[ measurement conditions ]

Sample concentration: 0.5 wt% (tetrahydrofuran (THF) solution)

Sample injection amount: 100 μ L

Eluent: THF (tetrahydrofuran)

Flow rate: 1.0 mL/min

Measurement temperature: 40 deg.C

The column: TSKgel GMHHR-H (20)2 root

Protection column: TSKgel HXL-H

The detector: differential refractometer

Standard polystyrene molecular weight: 1 to 2000 thousands (made by Tosoh corporation)

As the acrylic pressure-sensitive adhesive resin, an acrylic pressure-sensitive adhesive resin containing a tackifier resin is preferably used in order to improve adhesion to an adherend and surface adhesive strength.

The tackifier resin contained in the acrylic adhesive resin is not particularly limited, and may be appropriately selected according to the purpose, and is preferably a tackifier resin having a softening point of 30 to 180 ℃. When a (meth) acrylate-based tackifier resin is used, the tackifier resin preferably has a glass transition temperature of 30 to 200 ℃, and more preferably 50 to 160 ℃.

Specific examples of the tackifier resin contained in the acrylic adhesive resin include rosin-based tackifier resin, polymerized rosin ester-based tackifier resin, rosin phenol-based tackifier resin, stabilized rosin ester-based tackifier resin, disproportionated rosin ester-based tackifier resin, hydrogenated rosin ester-based tackifier resin, terpene phenol-based tackifier resin, petroleum resin-based tackifier resin, and (meth) acrylate-based tackifier resin. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among them, the above-mentioned tackifier resins are preferably polymerized rosin ester-based tackifier resins, rosin phenol-based tackifier resins, disproportionated rosin ester-based tackifier resins, hydrogenated rosin ester-based tackifier resins, terpene phenol-based resins, and (meth) acrylate-based resins.

The amount of the tackifier resin used is not particularly limited and may be appropriately selected depending on the purpose, and is preferably within a range of 5 to 65 parts by weight based on 100 parts by weight of the acrylic polymer, and more preferably within a range of 8 to 55 parts by weight because adhesiveness to an adherend is easily secured.

As the acrylic adhesive resin, an acrylic adhesive resin containing a crosslinking agent is preferably used in order to further increase the cohesive force of the adhesive layer.

The crosslinking agent is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, a metal chelate-based crosslinking agent, and an aziridine-based crosslinking agent. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these, the crosslinking agent is preferably a type of crosslinking agent which is mixed after the production of the acrylic polymer to cause a crosslinking reaction to proceed, and more preferably an isocyanate-based crosslinking agent and an epoxy-based crosslinking agent which are highly reactive with the acrylic polymer are used.

Examples of the isocyanate-based crosslinking agent include toluene diisocyanate, triphenylmethane isocyanate, naphthalene-1, 5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane-modified toluene diisocyanate, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among them, toluene diisocyanate, a trimethylolpropane adduct thereof, and triphenylmethane isocyanate, which are 3-functional polyisocyanate-based compounds, are particularly preferable.

As an index of the degree of crosslinking, a value of gel fraction obtained by measuring an insoluble component after immersing the pressure-sensitive adhesive layer in toluene for 24 hours was used. The gel fraction of the adhesive layer is not particularly limited and may be appropriately selected depending on the purpose, and is preferably 10 to 70 wt%, more preferably 25 to 65 wt%, and even more preferably 35 to 60 wt% in order to obtain an adhesive layer having good cohesiveness and adhesiveness.

The gel fraction is a value measured by the following method. A pressure-sensitive adhesive composition containing the pressure-sensitive adhesive resin and, if necessary, the additive was applied to a release sheet so that the thickness after drying became 50 μm, and the sheet was dried at 100 ℃ for 3 minutes, aged at 40 ℃ for 2 days, and the resultant was cut into 50mm squares to obtain samples. Next, the weight of the sample before toluene immersion was measured in advance (G1), the toluene-insoluble matter of the sample after immersion in a toluene solution at 23 ℃ for 24 hours was separated by filtration through a 300 mesh metal net, the weight of the residue after drying at 110 ℃ for 1 hour was measured (G2), and the gel fraction was determined 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 binder composition.

Gel fraction (wt%) (G2-G3)/(G1-G3) × 100 … formula (4)

Rubber-based adhesive resin-

The rubber-based binder resin is not particularly limited, and examples thereof include resins containing a rubber material that can be generally used as a binder resin, such as a synthetic rubber-based binder resin and a natural rubber-based binder resin, and, if necessary, additives such as a tackifier resin.

Examples of the rubber material include a block copolymer of a polyaromatic vinyl compound and a conjugated diene compound; 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. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these, the styrene-based resin is preferable, and when 2 or more kinds of the styrene-based resins are used in combination, the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer are particularly preferably used in combination because excellent adhesive properties and holding power can be imparted to the adhesive sheet.

The styrene-based resin may be a single structure styrene-based resin having a linear structure, a branched structure or a multi-branched structure, or may be a mixture of styrene-based resins having different structures. When a styrene resin having a rich linear structure is used for the adhesive layer, excellent adhesive performance can be imparted to the adhesive sheet. On the other hand, a resin having a branched structure or a multibranched structure and having a styrene block at a molecular end can have a quasi-crosslinked structure and can impart excellent cohesive force, and thus can impart high holding power. Therefore, the styrene resin is preferably used in combination according to the required characteristics.

As the styrene-based resin, a styrene-based resin having a constitutional unit represented by the following chemical formula (1) in a range of 10 to 80 wt% based on the total weight of the styrene-based resin is preferably used, more preferably a styrene-based resin having a constitutional unit represented by the following chemical formula (1) in a range of 12 to 60 wt%, still more preferably a styrene-based resin having a constitutional unit represented by the following chemical formula (1) in a range of 15 to 40 wt%, and particularly preferably a styrene-based resin having a constitutional unit represented by the following chemical formula (1) in a range of 17 to 35 wt%. This can provide excellent adhesiveness and heat resistance.

[ chemical formula 1]

When the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer are used in combination as the styrene resin, the content of the styrene-isoprene copolymer is preferably 0 to 80 wt%, more preferably 0 to 77 wt%, even more preferably 0 to 75 wt%, and particularly preferably 0 to 70 wt%, based on the total weight of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer. When the content of the styrene-isoprene copolymer is within the above preferable range, the adhesive sheet can achieve both excellent adhesive properties and thermal durability.

The styrene-isoprene copolymer is preferably a styrene-isoprene copolymer having a weight average molecular weight in the range of 1 to 80 ten thousand, more preferably a styrene-isoprene copolymer having a weight average molecular weight in the range of 3 to 50 ten thousand, and still more preferably a styrene-isoprene copolymer having a weight average molecular weight in the range of 5 to 30 ten thousand, as measured in terms of standard polystyrene by Gel Permeation Chromatography (GPC). When the weight average molecular weight of the styrene-isoprene copolymer is within the above preferable range, the adhesive sheet can ensure heat fluidity and compatibility when diluted with a solvent, and therefore, the adhesive sheet can be obtained with good workability in the production process and with thermal durability, which is preferable.

The weight average molecular weight of the styrene-isoprene copolymer measured by GPC was a standard polystyrene conversion value measured by a GPC apparatus (SC-8020, manufactured by Tosoh corporation), and the measurement conditions were as follows.

[ measurement conditions ]

Sample concentration: 0.5 wt% (tetrahydrofuran solution)

Sample injection amount: 100 μ L

Eluent: tetrahydrofuran (THF)

Flow rate: 1.0 mL/min

Measurement temperature: 40 deg.C

The column: TSKgel (registered trademark) GMHHR-H (20)2

Protection column: t SKgel HXL-H

The detector: differential refractometer

The method for producing the styrene-isoprene copolymer is not particularly limited, and may be appropriately selected from conventionally known production methods, and examples thereof include a method of polymerizing a styrene block and an isoprene block step by an anionic living polymerization method.

The method for producing the styrene-isoprene-styrene copolymer is not particularly limited, and may be appropriately selected from conventionally known production methods, and examples thereof include a method of polymerizing a styrene block and an isoprene block step by an anionic living polymerization method, a method of producing a block copolymer having living active terminals, and then reacting the block copolymer with a coupling agent to produce a coupled block copolymer, and the like.

The method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited, and may be appropriately selected from conventionally known production methods, and examples thereof include a method of mixing the styrene-isoprene copolymer produced by the above method and the styrene-isoprene-styrene copolymer.

Further, as a method for producing a mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer, the mixture may be produced simultaneously in one polymerization step.

In a more specific embodiment, a styrene monomer is first polymerized in a polymerization solvent using an anionic polymerization initiator by an anionic living polymerization method to form a polystyrene block having living active terminals. Secondly, isoprene is polymerized using the living active end of the polystyrene block to obtain a styrene-isoprene diblock copolymer having a living active end. Thirdly, a part of the styrene-isoprene diblock copolymer having the living active terminal is reacted with a coupling agent to form a coupled styrene-isoprene-styrene block copolymer. Fourthly, the living active terminal of the remaining portion of the styrene-isoprene diblock copolymer having the living active terminal is inactivated by using a polymerization terminator to form a styrene-isoprene diblock copolymer.

The tackifier resin contained in the rubber-based adhesive resin is not particularly limited and may be appropriately selected according to the purpose, and a tackifier resin having a softening point of 80 ℃ or higher is preferably used. Thus, the pressure-sensitive adhesive sheet can be obtained which has excellent initial adhesiveness and thermal durability.

The tackifier resin is preferably a solid tackifier resin at room temperature (23 ℃), and specific examples thereof include C₅Petroleum resin, C₉Petroleum resin, C₅System C₉Petroleum resins such as petroleum resin series, alicyclic petroleum resin series, polymerized rosin resin series, terpene resin series, rosin resin series, terpene-phenolic resin, styrene resin, coumarone-indene resin, xylene resin, phenolic aldehydeResins, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these, it is preferable to use the above-mentioned C in combination as the tackifier resin in view of achieving both of further excellent initial adhesiveness and thermal durability₅Petroleum resin and polymerized rosin resin.

The petroleum resin is easily compatible with the structural unit represented by the chemical formula (1) constituting the styrene resin, and as a result, the initial adhesion and thermal durability of the adhesive sheet can be further improved.

As the above-mentioned C₅Examples of the petroleum resin include ESCOREZ 1202, ESCOREZ 1304, ESCOREZ 1401 (manufactured by Exxon Mobil Co., Ltd.), Wingtack 95 (manufactured by Goodyear Tire and Rubber Company Co., Ltd.), Quintone K100, Quintone R100, Quintone F100 (manufactured by ZEON corporation Co., Ltd., Japan), Piccotac 95, and Piccopale 100 (manufactured by Rika Hercules Co., Ltd.).

As the above-mentioned C₉Examples of the stone-based oleoresin include Nisseki Neoplast L-90, Nisseki Neoplast 120, Nisseki Neoplast 130, Nisseki Neoplast 140, Nisseki Neoplast 150, Nisseki Neoplast 170S, Nisseki Neoplast 160, Nisseki Neoplast E-100, Nisseki Neoplast E-130, Nisseki Neoplast 130S, Nisseki Neoplast S (manufactured by JX Nissajouterio Kagaku Co., Ltd.), and Petcol (registered trademark) (manufactured by Tosoh Co., Ltd.).

As the above-mentioned C₅System C₉The above-mentioned petroleum resin C can be used₅A petroleum resin and the above C₉Examples of the copolymer of the petroleum resin include ESCOREZ 2101 (available from Exxon Mobil Co., Ltd.), Quintone G115 (available from ZEON corporation, Japan), and Hercotac 1149 (available from Rika Hercules Co., Ltd.).

The alicyclic petroleum resin may be the same as C₉Examples of the hydrogenated petroleum resin include ESCOREZ 5300 (manufactured by Exxon Mobil Co., Ltd.), Alcon P-100 (manufactured by Mitsukawa chemical Co., Ltd.), Rigalite R101 (manufactured by Rika Hercules Co., Ltd.).

The amount of the tackifier resin used is not particularly limited and may be appropriately selected depending on the purpose, and is preferably within a range of 0 to 100 wt%, more preferably within a range of 0 to 70 wt%, further preferably within a range of 0 to 50 wt%, and particularly preferably within a range of 0 to 30 wt%, based on the total amount of the components constituting the rubber-based adhesive resin. By using the tackifier resin within the above preferable range, the interface adhesion between the adhesive layer and the base layer is improved, and the excellent elongation at break and thermal durability of the adhesive sheet are both easily achieved.

The amount of the tackifier resin having a softening point of 80 ℃ or higher is not particularly limited, and may be appropriately selected according to the purpose, and is preferably within a range of 3 wt% to 100 wt%, more preferably within a range of 5 wt% to 80 wt%, based on the total amount of the styrene resin, and is particularly preferably within a range of 5 wt% to 80 wt%, from the viewpoint of obtaining the adhesive sheet having both further excellent adhesiveness and excellent thermal durability.

For the purpose of obtaining the adhesiveness and initial adhesiveness in a constant temperature environment, a tackifier resin having a softening point of-5 ℃ or lower may be used in combination with the tackifier resin having a softening point of 80 ℃ or higher.

The tackifier resin having a softening point of-5 ℃ or lower is not particularly limited, and may be appropriately selected from known ones, and a tackifier resin that is liquid at room temperature is preferably used.

Specific examples of the tackifier resin having a softening point of-5 ℃ or lower include process oils, polyesters, liquid rubbers such as polybutene, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among them, polybutene is preferably used as the tackifier resin having a softening point of-5 ℃ or lower, from the viewpoint of further excellent initial adhesiveness.

The tackifier resin having a softening point of-5 ℃ or lower is preferably used in a range of 0 to 40% by weight, more preferably 0 to 30% by weight, based on the total amount of the tackifier resin.

Further, the tackifier resin having a softening point of-5 ℃ or lower is preferably used in a range of 0 to 40 wt% based on the total amount of the styrene resin, and more preferably used in a range of 0 to 30 wt%, since initial adhesion can be improved to achieve good adhesion and sufficient thermal durability can be obtained.

The weight ratio of the tackifier resin having a softening point of 80 ℃ or higher to the tackifier resin having a softening point of-5 ℃ or lower is not particularly limited, and may be appropriately selected depending on the purpose, and is preferably used in a range of 5 to 50 in terms of [ weight of the tackifier resin having a softening point of 80 ℃ or higher/weight of the tackifier resin having a softening point of-5 ℃ or lower ], and more preferably in a range of 10 to 30 in terms of obtaining the adhesive sheet having both excellent initial adhesiveness and excellent holding power.

The weight ratio of the styrene resin to the tackifier resin is not particularly limited, and may be appropriately selected according to the purpose, but is preferably in the range of 0.5 to 10.0, and more preferably in the range of 0.6 to 9.0, since the initial adhesion can be improved and excellent thermal durability can be obtained when the weight ratio of the styrene resin to the tackifier resin, as represented by [ styrene resin/tackifier resin ]. In addition, the weight ratio [ styrene-based resin/tackifier resin ] is preferably greater than 1, for example, from the viewpoint of preventing peeling (repulsion resistance) due to the repulsive force of the pressure-sensitive adhesive sheet when the pressure-sensitive adhesive sheet is attached to a curved surface portion of an adherend.

Other ingredients-

The other components in the pressure-sensitive adhesive composition are not particularly limited and may be appropriately selected within a range that does not impair the properties of the pressure-sensitive adhesive sheet, and examples thereof include polymer components other than the pressure-sensitive adhesive resin, filler particles, a crosslinking agent, an anti-aging agent, an ultraviolet absorber, a filler, a polymerization inhibitor, a surface conditioner, an antistatic agent, an antifoaming agent, a viscosity modifier, a light-resistant stabilizer, a weather-resistant stabilizer, a heat-resistant stabilizer, an antioxidant, a leveling agent, an organic pigment, an inorganic pigment, a pigment dispersant, a plasticizer, a softening agent, a flame retardant, and an additive such as a metal deactivator. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among them, the filler particles are preferably contained.

The content of the other components in the adhesive layer may be appropriately selected within a range that does not impair the properties of the adhesive sheet.

When the adhesive layer contains the filler particles, the filler particles are exposed from the adhesive layer when the adhesive sheet is stretched, and thus the adhesive area between the adhesive layer and an adherend is reduced, and therefore, even if the stretching direction of the adhesive sheet is a direction perpendicular to the adhesion surface (bonding surface) of the adherend, the adhesive sheet can be easily peeled off by stretching, which is advantageous in that.

The type of the filler particles is not particularly limited, and may be appropriately selected within a range not impairing the effects of the present invention, and may be inorganic filler particles or organic filler particles. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

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, hydrates of tin oxide, borax, zinc borate, zinc metaborate, barium metaborate, zinc carbonate, magnesium carbonate-calcium, calcium carbonate, barium carbonate, molybdenum oxide, antimony oxide, red phosphorus, mica, clay, kaolin, talc, zeolite, wollastonite, montmorillonite, silica (quartz, fumed silica, precipitated silica, silicic anhydride, fused silica, crystalline silica, ultrafine amorphous silica, etc.) ], Potassium titanate, magnesium sulfate, sepiolite, xonotlite, aluminum borate, barium sulfate, barium titanate, zirconium oxide, cerium, tin, indium, carbon, sulfur, tellurium, cobalt, molybdenum, strontium, chromium, barium, lead, tin oxide, indium oxide, diamond, magnesium, platinum, zinc, manganese, stainless steel, antimony pentoxide, and the like. Among them, aluminum hydroxide, nickel and the like are preferable.

In order to improve the dispersibility in the binder resin, the inorganic filler may be an inorganic filler subjected to a surface treatment such as a silane coupling treatment or a stearic acid treatment.

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

The shape of the filler particles is not particularly limited, and may be appropriately selected according to the purpose, and may be a regular shape or an irregular shape. Specific examples of the shape of the filler particles include polygonal shapes, cubic shapes, elliptical shapes, spherical shapes, needle shapes, flat plates, scaly shapes, and the like. The filler particles having these shapes may be used alone in 1 kind, or may be used in combination in 2 or more kinds. Further, the filler particles having these shapes may be aggregated. Among them, the shape of the filler particles is preferably an elliptical shape, a spherical shape, or a polygonal shape. When the filler particles have an elliptical, spherical, polygonal or other shape, the adhesive layer slides well against the adherend when the adhesive sheet is stretched, and the adhesive sheet can be easily peeled off by stretching even if the direction of stretching of the adhesive sheet is 90 ° to the surface to which the adherend is attached.

As the particle size distribution (D) of the above filler particles₉₀/D₁₀) The amount of the filler is not particularly limited, and may be suitably selected according to the purpose, but is preferably 2.5 to 20, more preferably 2.5 to 15, and still more preferably 2.5 to 5 in view of impact resistance. If the particle size of the above-mentioned filler particlesDistribution (D)₉₀/D₁₀) Within the above preferred range, the pressure-sensitive adhesive sheet can be easily peeled off by elongation even when the direction of elongation of the pressure-sensitive adhesive sheet is 90 ° to the adherend surface, and is less likely to crack even when the thickness of the substrate of the pressure-sensitive adhesive sheet is small, and has excellent impact resistance, shear adhesion and tear adhesion. On the other hand, if the particle size distribution (D) of the above-mentioned filler particles₉₀/D₁₀) When the elongation direction of the pressure-sensitive adhesive sheet is less than 2.5, the elongation peelability in the direction of 90 ° to the adherend surface of the pressure-sensitive adhesive sheet may be impaired, and when it exceeds 20, the pressure-sensitive adhesive properties such as impact resistance, shear adhesion, and split adhesion may be impaired.

Particle size distribution (D) of the above filler particles₉₀/D₁₀) For example, the particle size of the filler particles is measured by using a measuring instrument (Microtrac) using a laser diffraction scattering method, and converted into a particle size distribution.

The volume average particle diameter of the filler particles is not particularly limited and may be appropriately selected depending on the purpose, and is preferably 3 to 25 μm, more preferably 5 to 20 μm, and still more preferably 5 to 14 μm. When the volume average particle diameter of the filler particles is within the above preferred range, the pressure-sensitive adhesive sheet can be easily peeled off by elongation even when the direction of elongation of the pressure-sensitive adhesive sheet is 90 ° to the adherend surface, and the pressure-sensitive adhesive sheet is less likely to crack even when the thickness of the substrate is small, and is excellent in impact resistance, shear adhesion and fracture adhesion. On the other hand, if the volume average particle diameter of the filler particles is less than 3 μm, the adhesive sheet may be difficult to be peeled off by elongation when the elongation direction of the adhesive sheet is 90 ° to the adherend surface, and if it exceeds 25 μm, the adhesive properties such as impact resistance, shear adhesion, and fracture adhesion may be impaired.

The volume average particle diameter of the filler particles can be measured, for example, by using a measuring instrument (Microtrac) using a laser diffraction scattering method.

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 may be appropriately selected according to the purpose, and the ratio of the volume average particle diameter of the filler particles to the average thickness of the adhesive layer, which is represented by [ volume average particle diameter of the filler particles/average thickness of the adhesive layer ], is preferably 5/100 or more, more preferably 5/100 to 95/100, still more preferably 10/100 to 75/100, and particularly preferably 20/100 to 60/100. If the above ratio is within the above preferred range, the pressure-sensitive adhesive sheet can be easily peeled off by stretching even if the stretching direction of the pressure-sensitive adhesive sheet is 90 ° to the adherend surface, and the pressure-sensitive adhesive sheet is less likely to be broken even if the thickness of the substrate is small. Further, if the above ratio is within the above particularly preferred range, the pressure-sensitive adhesive sheet can be easily peeled off by stretching even if the stretching direction of the pressure-sensitive adhesive sheet is 90 ° to the adherend surface, and is less likely to be broken even when the thickness of the substrate of the pressure-sensitive adhesive sheet is small, and is advantageous in that the pressure-sensitive adhesive sheet is further excellent in adhesive properties such as impact resistance, shear adhesion, and split adhesion. On the other hand, if the ratio is less than 5/100, the adhesive sheet may have impaired elongation peeling properties when the adhesive sheet is stretched in a direction of 90 ° relative to the adherend surface, and if it exceeds 95/100, the adhesive properties such as impact resistance, shear adhesion, and split adhesion may be impaired.

The content of the filler particles in the adhesive layer is not particularly limited and may be appropriately selected according to the purpose, and is preferably 10 to 90 parts by weight, more preferably 15 to 50 parts by weight, and still more preferably 20 to 40 parts by weight, based on 100 parts by weight of the adhesive resin. If the content of the filler particles is less than 10 parts by weight relative to 100 parts by weight of the pressure-sensitive adhesive resin, the pressure-sensitive adhesive sheet may not be peeled off by elongation when the direction of elongation of the pressure-sensitive adhesive sheet is 90 ° relative to the surface to be adhered of an adherend, or the pressure-sensitive adhesive sheet may be broken, and the pressure-sensitive adhesive sheet may not be peeled off by elongation. In addition, if the content of the filler particles exceeds 90 parts by weight with respect to 100 parts by weight of the binder resin, there are cases where: the pressure-sensitive adhesive sheet does not stretch, the pressure-sensitive adhesive composition remains on the adherend, impact resistance deteriorates, and shear adhesion and fracture adhesion deteriorate. On the other hand, if the content of the filler particles is within the above preferred range, the pressure-sensitive adhesive sheet can be easily peeled off by stretching even if the stretching direction of the pressure-sensitive adhesive sheet is 90 ° to the adherend surface, and the pressure-sensitive adhesive sheet is less likely to crack even if the thickness of the substrate is small, and is advantageous in that the pressure-sensitive adhesive sheet is excellent in impact resistance, shear adhesion, and fracture adhesion.

The content of the filler particles in the adhesive layer may be appropriately adjusted at the time of preparing the adhesive composition.

The volume ratio of the filler particles to the volume of the entire adhesive layer is not particularly limited and may be appropriately selected according to the purpose, and is preferably 4% to 40%, more preferably 5% to 30%, still more preferably 5% to 20%, and particularly preferably 5% to 15%. If the volume ratio of the filler particles is less than 4%, the adhesive sheet may not be peeled off by elongation when the direction of elongation of the adhesive sheet is 90 ° to the surface to be adhered of an adherend, or the adhesive sheet may be broken, and the adhesive sheet may not be peeled off by elongation. In addition, if the volume ratio of the filler particles exceeds 40%, the following may occur: the pressure-sensitive adhesive sheet does not stretch, the pressure-sensitive adhesive composition remains on an adherend, impact resistance deteriorates, and shear adhesion and fracture adhesion deteriorate. On the other hand, if the volume ratio of the filler particles is within the above preferred range, the pressure-sensitive adhesive sheet can be easily peeled off by stretching even if the stretching direction of the pressure-sensitive adhesive sheet is 90 ° to the adherend surface, and the pressure-sensitive adhesive sheet is less likely to crack even if the thickness of the substrate is small, and is advantageous in that the pressure-sensitive adhesive sheet is excellent in impact resistance, shear adhesion, and fracture adhesion.

The volume ratio of the filler particles to the adhesive layer can be calculated from the following formulas (1) to (3).

Adhesive resin^*1Weight of A (g)/binder resin^*1Density A (g/cm)³) Binder resin^*1Volume A (cm) of³) … type (1)

Weight B (g) of filler particles/FillerDensity B (g/cm) of the particles³) Volume B (cm) of filler particles³) … type (2)

Volume B (cm) of filler particles³) /(adhesive resin)^*1Volume A (cm) of³) + volume B (cm) of filler particles³) X 100 ═ volume ratio of filler particles (%) … formula (3)

In the above formulas (1) and (3),^*1the binder resin may include paragraph [0079 ] described later]The other components described in (1).

The density is a value measured according to JIS Z8804.

The number of the adhesive layers is not particularly limited, and may be appropriately selected depending on the purpose of use, etc., and may be disposed on only one side of the adhesive sheet, or may be disposed on both sides, and preferably is disposed on both sides.

Stress at 25% elongation of the adhesive layer-

The stress at 25% elongation of the adhesive layer is not particularly limited and may be appropriately selected depending on the purpose, and is preferably 0.04 to 0.4MPa, and more preferably 0.05 to 0.1 MPa. When the stress at 25% elongation of the pressure-sensitive adhesive layer is within the above preferred range, an adhesive strength suitable for the pressure-sensitive adhesive sheet can be obtained, and peeling can be relatively easily performed even in the case of elongation peeling. On the other hand, if the stress at 25% elongation of the pressure-sensitive adhesive layer is less than 0.04MPa, the pressure-sensitive adhesive sheet may peel off when a load in the shear direction of the pressure-sensitive adhesive sheet is generated while fixing hard adherends to each other, and if it exceeds 0.4MPa, the force required to elongate the pressure-sensitive adhesive sheet may become excessive when peeling off the pressure-sensitive adhesive sheet.

The stress at 25% elongation of the adhesive layer is a stress value measured when the adhesive layer is punched into a dumbbell shape having a gauge length of 20mm and a width of 10mm, and elongated at 25% elongation under a condition of a measuring atmosphere of 23 ℃ and 50% RH using a Tensilon tensile tester (model: RTF-1210, manufactured by A & D) at a tensile rate of 300 mm/min in the longitudinal direction.

Stress at the break point of the bond line-

The stress at the breaking point of the adhesive layer is not particularly limited and may be appropriately selected depending on the purpose, and is preferably 0.5 to 2.1MPa, and more preferably 1.0 to 2.1 MPa. If the stress at the breaking point of the adhesive layer is within the above-described preferable range, even when the pressure-sensitive adhesive sheet is pulled and peeled, the pressure-sensitive adhesive sheet can be prevented from breaking, and the load for stretching the pressure-sensitive adhesive sheet is not excessively excessive, so that the re-peeling operation by peeling becomes easy. On the other hand, if the stress at the breaking point of the adhesive layer is less than 0.5MPa, the adhesive sheet may break when the adhesive sheet is peeled by stretching, and if it exceeds 2.1MPa, the adhesive sheet may not be sufficiently stretched and may not be peeled again when the adhesive sheet is peeled by stretching. The force required to stretch and deform the pressure-sensitive adhesive sheet also depends on the thickness of the pressure-sensitive adhesive sheet, and for example, when the pressure-sensitive adhesive sheet having a large thickness and a high stress at break point is to be stretched and re-peeled, the pressure-sensitive adhesive sheet may not be sufficiently stretched and re-peeled.

The stress at break point of the adhesive layer was measured by punching the adhesive layer into a dumbbell shape having a gauge length of 20mm and a width of 10mm, and stretching the adhesive layer in the longitudinal direction at a stretching speed of 300 mm/min using a Tensilon tensile tester (model: RTF-1210, manufactured by Kabushiki Kaisha A & D) under a measuring atmosphere of 23 ℃ and 50% RH.

Elongation at the breaking point of the adhesive layer-

The breaking point elongation of the pressure-sensitive adhesive layer is not particularly limited and may be appropriately selected depending on the purpose, and is preferably 450% to 1300%, more preferably 500% to 1200%, and still more preferably 600% to 1100%. When the elongation at the breaking point of the adhesive layer is within the above preferable range, both favorable adhesiveness and removability can be achieved.

The elongation at break of the adhesive layer was determined by punching the adhesive layer into a dumbbell shape having a gauge length of 20mm and a width of 10mm, and stretching the adhesive layer in the longitudinal direction at a stretching speed of 300 mm/min using a Tensilon tensile tester (model: RTF-1210, manufactured by A & D) under a measuring atmosphere of 23 ℃ and 50% RH, and then breaking the adhesive layer.

Average thickness of the adhesion layer

The average thickness of the adhesive layer is not particularly limited and may be appropriately selected depending on the purpose, and is preferably 5 to 150 μm, more preferably 20 to 120 μm, still more preferably 40 to 110 μm, and particularly preferably 50 to 100 μm. The "average thickness of the adhesive layer" means an average thickness of the adhesive layer on one side of the adhesive sheet. In the case where the adhesive layers are provided on both sides of the adhesive sheet, the average thickness of the adhesive layer on one side may be the same as or different from the average thickness of the adhesive layer on the other side, and preferably the same thickness.

In the present specification, the "average thickness of the adhesive layer" refers to an average value of the total thickness of 25 parts obtained by cutting the adhesive sheet at 5 parts in the width direction at intervals of 100mm in the longitudinal direction and measuring the total thickness of the adhesive layer at 5 parts in the width direction at intervals of 100mm using a TH-104 paper/film thickness measuring machine (manufactured by TESTER SANG YO corporation).

Method for forming an adhesion layer

The method for forming the adhesive layer is not particularly limited, and may be appropriately selected from known methods according to the purpose, and examples thereof include a method of forming the adhesive layer on at least one surface of the base material layer by a method such as a hot press method, a casting method by extrusion molding, a uniaxial stretching method, a sequential biaxial stretching method, a simultaneous biaxial stretching method, an inflation method, a tube method, a rolling method, or a solution method. Among them, a casting method and a solution method by extrusion molding are preferable.

Examples of the solution method include a method in which a solution containing the pressure-sensitive adhesive composition is directly applied to the base material layer by a roll coater or the like, and a method in which the pressure-sensitive adhesive layer is formed on a release sheet and then released.

Substrate layer > > >

The substrate layer is not particularly limited, and may be appropriately selected from known materials that can be used for adhesive sheets within a range that does not impair the properties of the adhesive sheet, and preferably includes the following materials for substrates, and may further include other components as necessary.

The substrate layer may have a single-layer structure, or may have a multilayer structure of 2, 3 or more layers.

Material for substrate

Examples of the material for the substrate include styrene 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 polyurethanes and ether-based polyurethanes; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene; a polycarbonate; polymethylpentene; polysulfones; polyether ether ketone; polyether sulfone; a polyetherimide; a polyimide film; a fluororesin; nylon; acrylic resins, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds, preferably 2 or more kinds.

Among these, the styrene-based resin and the polyurethane resin are preferable because suitable elongation at break and stress at break can be easily obtained, and the styrene-based resin is more preferable, and a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer are particularly preferably used in combination.

- - -styrene series resin- - -

Since the styrene resin is a thermoplastic resin, it is excellent in moldability in molding such as extrusion molding and injection molding, and the base layer can be easily molded. In addition, the styrene-based resin can easily give particularly excellent elongation at break in a resin group generally called a thermoplastic resin, and can be suitably used as a base material of the pressure-sensitive adhesive sheet.

Therefore, in the base material, the styrene-based resin is preferably 50% to 100%, more preferably 60% to 100%, even more preferably 65% to 100%, and particularly preferably 70% to 100%, based on the total resin components. When the proportion of the styrene resin is within the above preferable range, a base layer having excellent elongation at break and stress at break can be obtained.

The styrene-based resin may be a single structure styrene-based resin having a linear structure, a branched structure or a multi-branched structure, or may be a mixture of styrene-based resins having different structures. The styrene resin having a rich linear structure can impart an excellent elongation at break to the base material layer. On the other hand, when the copolymer has a branched structure or a multibranched structure and a styrene block is arranged at a molecular terminal, the copolymer can have a quasi-crosslinked structure and can impart excellent cohesive force. Therefore, the styrene-based resins are preferably used in combination according to the desired mechanical properties.

As the styrene-based resin, a styrene-based resin having a constitutional unit represented by the above chemical formula (1) in a range of 13 to 60 wt% based on the total weight of the styrene-based resin is preferably used, more preferably a styrene-based resin having a constitutional unit represented by the above chemical formula (1) in a range of 15 to 50 wt%, still more preferably a styrene-based resin having a constitutional unit represented by the above chemical formula (1) in a range of 15 to 45 wt%, and particularly preferably a styrene-based resin having a constitutional unit represented by the above chemical formula (1) in a range of 15 to 35 wt%. When the ratio of the structural unit represented by the following chemical formula (1) to the total weight of the styrene-based resin is within the above preferred range, the elongation at break and stress at break can be easily obtained within the appropriate ranges.

When the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer are used in combination as the styrene resin, the content of the styrene-isoprene copolymer is preferably 0 to 80 wt%, more preferably 0 to 70 wt%, even more preferably 0 to 50 wt%, and particularly preferably 0 to 30 wt%, based on the total weight of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer. When the content of the styrene-isoprene copolymer is within the above-described preferable range, the thermal durability can be achieved while maintaining excellent elongation at break and stress at break.

The styrene-isoprene copolymer is preferably a styrene-isoprene copolymer having a weight average molecular weight in the range of 1 to 80 ten thousand, more preferably 3 to 50 ten thousand, and still more preferably 5 to 30 ten thousand, as measured in terms of standard polystyrene by Gel Permeation Chromatography (GPC). When the weight average molecular weight of the styrene-isoprene copolymer is within the above preferable range, the substrate layer having good workability in the production process and thermal durability can be obtained because the fluidity under heating and the compatibility upon dilution with a solvent can be secured, which is preferable.

The measurement of the weight average molecular weight of the styrene-isoprene copolymer by the GPC method is the same as that described in the section of "-rubber-based binder resin".

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 may be appropriately selected from conventionally known production methods, and examples thereof include the same methods as those described in the above-mentioned section "rubber-based binder resin".

-polyurethane resins-

The urethane resin is not particularly limited and may be appropriately selected according to the purpose, and is preferably a urethane resin having a softening point of 40 ℃ or higher, and more preferably a urethane resin having a softening point of 50 ℃ or higher. The upper limit of the softening point is preferably 100 ℃ or lower. The softening point is a value measured in accordance with JIS K2207 (dry ball type) (hereinafter, the same applies to the softening point).

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

The polyol (b1-1) is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include polyester polyols, polyether polyols, polycarbonate polyols, and acrylic polyols. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these, the polyol (b1-1) is preferably a polyester polyol or a polyether polyol because the mechanical properties of the substrate layer can be obtained. In the above base material layer, a polyester polyol is preferably used when heat resistance is required, and a polyether polyol is preferably used when water resistance and biodegradability are required.

Examples of the polyester polyol include polyesters obtained by esterification of a low molecular weight polyol with a polycarboxylic acid, polyesters obtained by ring-opening polymerization of a cyclic ester compound such as e-caprolactone, and copolyesters thereof.

Examples of the low molecular weight polyol that can be used for producing 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, and cyclohexanedimethanol, which have a weight average molecular weight of approximately 50 to 300.

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.

Examples of the polyether polyol include polyether polyols obtained by addition polymerization of alkylene oxides using 1 or 2 or more species of compounds having 2 or more active hydrogen atoms as an initiator, and the like.

As the polycarbonate polyol, for example, a polycarbonate polyol obtained by reacting a carbonate and/or phosgene with a low molecular weight polyol described later can be used.

Examples of the carbonate include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclic carbonate, diphenyl carbonate, and the like.

Examples of the low-molecular-weight polyol which can be used for the production of the polycarbonate polyol and which is capable of reacting with the carbonate 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, 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' -biphenol and the like.

The polyisocyanate (b1-2) is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include alicyclic polyisocyanates, aliphatic polyisocyanates, and aromatic polyisocyanates. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

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

The method for producing the urethane resin (b1) by reacting the polyol (b1-1) with the polyisocyanate (b1-2) is not particularly limited, and may be appropriately selected from conventionally known production methods, and examples thereof include the following methods: the polyol (b1-1) charged into the reaction vessel is heated under normal pressure or reduced pressure to remove moisture, and then the polyisocyanate (b1-2) is supplied at once or in portions to be reacted.

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

The reaction conditions of the polyol (b1-1) and the polyisocyanate (b1-2) are not particularly limited, and may be suitably selected in consideration of safety, quality, cost, and the like, and the reaction temperature is preferably 70 to 120 ℃ and the reaction time is preferably 30 minutes to 5 hours.

When the polyol (b1-1) is reacted with the polyisocyanate (b1-2), a tertiary amine catalyst, an organometallic catalyst, or the like can be used as a catalyst, if necessary.

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 may be appropriately selected according to the purpose, and examples thereof include ester-based 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; amide solvents such as dimethylformamide and dimethylacetamide. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The organic solvent may be removed by a suitable method such as heating under reduced pressure or drying under normal pressure during the production of the polyurethane resin (b1) or after the production of the polyurethane (b 1).

Other components-

The other components in the base layer are not particularly limited, and may be appropriately selected within a range that does not impair the properties of the adhesive sheet, and examples thereof include tackifier resins; a polymer component other than the above-mentioned material for a base material; additives such as crosslinking agents, anti-aging agents, ultraviolet absorbers, fillers, polymerization inhibitors, surface conditioning agents, antistatic agents, antifoaming agents, viscosity modifiers, light-resistant stabilizers, weather-resistant stabilizers, heat-resistant stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, silica beads, organic beads and the like; inorganic fillers such as silica, alumina, titania, zirconia, and antimony pentoxide. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The content of the other components in the base layer may be appropriately selected within a range that does not impair the properties of the adhesive sheet.

The tackifier resin may be used for the purpose of improving adhesion between the pressure-sensitive adhesive layer and the base material layer in the pressure-sensitive adhesive sheet or improving heat resistance.

The tackifier resin is not particularly limited and may be appropriately selected according to the purpose, and is preferably a tackifier resin having a softening point of 80 ℃ or higher, more preferably a tackifier resin having a softening point of 90 ℃ or higher, still more preferably a tackifier resin having a softening point of 100 ℃ or higher, and particularly preferably a tackifier resin having a softening point of 110 ℃ or higher.

As the above-mentioned tackifier resin, for example, the tackifier resin described in the above-mentioned "-rubber-based adhesive resin-" can be used, and the same applies to the preferable embodiment and the like.

The above-mentioned antioxidants are not particularly limited, and can be appropriately selected from known antioxidants according to the purpose, and examples thereof include phenol antioxidants, phosphorus antioxidants (also referred to as "processing stabilizers"), amine antioxidants, imidazole antioxidants, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these, the phenol-based antioxidant and the phosphorus-based antioxidant are preferable, and when they are used in combination, the heat resistance stability of the base material can be effectively improved, and as a result, a psa sheet having further excellent heat durability while maintaining good initial adhesion can be obtained, which is preferable. The phosphorus-based antioxidant may slightly change color (yellow) with time in a high-temperature environment, and therefore the amount of the phosphorus-based antioxidant to be used is preferably set as appropriate in consideration of the balance between the initial adhesiveness, thermal durability, and prevention of discoloration.

As the phenol-based antiaging agent, a phenol-based compound having a sterically hindered group is usually used, and a monophenol type, a bisphenol type, and a polyphenol type are typical. Specific examples thereof include 2, 6-di-tert-butyl-4-methylphenol, 2 ' -methylenebis (4-methyl-6-tert-butylphenol), 2 ' -methylenebis (4-ethyl-6-tert-butylphenol), 4 ' -thiobis (6-tert-butyl-3-methylphenol), 4 ' -butylidenebis (3-methyl-6-tert-butylphenol), tetrakis [ methylene-3- (3 ', 5 ' -di-tert-butyl-4-hydroxyphenyl) propionate ] methane, n-octadecyl 3- (4 ' -hydroxy-3 ', 5 ' -di-tert-butylphenyl) propionate, and the like. These may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The amount of the phenolic antioxidant used is not particularly limited, and may be appropriately selected depending on the purpose, and is preferably in the range of 0.1 to 5 parts by weight based on 100 parts by weight of the base material, and when the amount is in the range of 0.5 to 3 parts by weight, the heat resistance stability of the base material can be effectively improved, and as a result, a pressure-sensitive adhesive sheet having further excellent heat durability while maintaining good initial adhesion can be obtained.

Stress at 25% elongation of the substrate layer-

The stress at 25% elongation of the base layer is not particularly limited, and may be appropriately selected according to the purpose, and is preferably 0.2 to 10.0MPa, more preferably 0.2 to 5.0MPa, further preferably 0.2 to 3.0MPa, and particularly preferably 0.2 to 2.0 MPa. When the stress at 25% elongation of the base material layer is within the above preferable range, an adhesive strength suitable for the adhesive sheet can be obtained, and peeling can be relatively easily performed even in the case of elongation peeling. On the other hand, if the stress at 25% elongation of the base material layer is less than 0.2MPa, the pressure-sensitive adhesive sheet may peel off when a load in the shear direction of the pressure-sensitive adhesive sheet is generated while fixing hard adherends to each other, and if it exceeds 10.0MPa, the force required to elongate the pressure-sensitive adhesive sheet may become excessively large when peeling the pressure-sensitive adhesive sheet.

The stress at 25% elongation of the substrate layer is a stress value measured when the substrate layer is punched into a dumbbell shape having a reticle length of 20mm and a width of 6mm, and elongated at 25% elongation under a condition of a measuring atmosphere of 23 ℃ and 50% RH using a Tensilon tensile tester (model: RTF-1210, manufactured by A & D) at a tensile rate of 500 mm/min in the longitudinal direction.

Breaking point stress of the substrate layer-

The breaking point stress of the base layer is not particularly limited, and may be appropriately selected according to the purpose, and is preferably 1.5 to 100.0MPa, more preferably 7.0 to 50.0MPa, still more preferably 7.0 to 40.0MPa, and particularly preferably 8.0 to 35.0 MPa. If the stress at the breaking point of the base material layer is within the above-described preferable range, even when the pressure-sensitive adhesive sheet is pulled and peeled, the pressure-sensitive adhesive sheet can be prevented from breaking, and the load for stretching the pressure-sensitive adhesive sheet is not excessively excessive, so that the re-peeling operation by peeling becomes easy. On the other hand, if the stress at the breaking point of the base material layer is less than 1.5MPa, the pressure-sensitive adhesive sheet may break when the pressure-sensitive adhesive sheet is stretched and peeled, and if it exceeds 100.0MPa, the pressure-sensitive adhesive sheet may not be sufficiently stretched and peeled again when it is desired to stretch and peel the pressure-sensitive adhesive sheet again. The force required to stretch and deform the pressure-sensitive adhesive sheet also depends on the thickness of the pressure-sensitive adhesive sheet, and for example, when the pressure-sensitive adhesive sheet is intended to be re-peeled by stretching the pressure-sensitive adhesive sheet having a large thickness and a high stress at break point, the pressure-sensitive adhesive sheet may not be sufficiently stretched and cannot be re-peeled.

The breaking point stress of the substrate layer was a stress value measured when the substrate layer was punched into a dumbbell shape having a reticle length of 20mm and a width of 6mm, and the dumbbell was stretched at a stretching speed of 500 mm/min in the longitudinal direction using a Tensilon tensile tester (model: RTF-1210, manufactured by Kabushiki Kaisha A & D) under a measuring atmosphere of 23 ℃ and 50% RH, thereby breaking the substrate.

Elongation at the breaking point of the substrate layer-

The breaking point elongation of the base material layer is not particularly limited and may be appropriately selected according to the purpose, and is preferably 200% to 1300%, more preferably 400% to 1300%, and still more preferably 700% to 1300%. When the elongation at break of the base material layer is 200% or more, even when the pressure-sensitive adhesive sheet is strongly adhered to an adherend, stress for stretching the pressure-sensitive adhesive sheet in the horizontal direction to the vertical direction with respect to the adherend surface does not become excessively large when the pressure-sensitive adhesive sheet is peeled again, and the pressure-sensitive adhesive sheet is not excessively elongated and can be easily peeled when peeled. Further, if the elongation at break point is 1300% or less, the stretching distance in the horizontal direction to the vertical direction with respect to the surface to be adhered of the adherend is not excessively long when the pressure-sensitive adhesive sheet is peeled off again, and the work can be performed in a small space. On the other hand, if the elongation at break point is less than 200%, peeling may not be performed due to breaking when the pressure-sensitive adhesive sheet is peeled off again by being pulled in the horizontal direction to the vertical direction with respect to the adherend surface, and if it exceeds 1300%, the pulling distance in the horizontal direction to the vertical direction with respect to the adherend surface may become too long when the pressure-sensitive adhesive sheet is peeled off again, and thus workability may be deteriorated.

The elongation at break of the substrate layer was determined by taking the substrate layer into a dumbbell shape having a gauge length of 20mm and a width of 6mm, and stretching the resulting product in the longitudinal direction at a stretching speed of 500 mm/min using a Tensilon tensile tester (model: RTF-1210, manufactured by Kagaku corporation, A & D) under a measuring atmosphere of 23 ℃ and 50% RH.

Average thickness of substrate layer-

The average thickness of the substrate layer is not particularly limited, and may be appropriately selected depending on the purpose of use, etc., and is preferably 10 to 500 μm, more preferably 10 to 300 μm, still more preferably 20 to 200 μm, and particularly preferably 20 to 100 μm. When the average thickness of the substrate layer is within the above-described preferred range, the pressure-sensitive adhesive sheet easily follows the strain of the adherend and easily obtains high adhesive strength, and the stress required when the pressure-sensitive adhesive sheet having the substrate layer is peeled off again while being stretched in the horizontal direction to the vertical direction with respect to the adherend surface is not excessively large, which is preferable.

In the present specification, the term "average thickness of the base material layer" means that the base material layer is cut at 5 places at intervals of 100mm in the longitudinal direction in the direction perpendicular to the longitudinal direction (sometimes referred to as "width direction"), and the thickness at 5 places is measured at intervals of 100mm in the width direction at each cut surface using a TH-104 paper/film thickness measuring machine (manufactured by stester SANGYO corporation), and an average value of the thicknesses at 25 places in total is obtained.

Average thickness of the adhesive layer/average thickness of the substrate layer-

The ratio of the thickness of the adhesive layer to the thickness of the base material layer is not particularly limited and may be appropriately selected according to the purpose, and the ratio of the average thickness of the adhesive layer to the average thickness of the base material layer, which is represented by [ average thickness of adhesive layer/average thickness of base material layer ], is preferably 1/5 to 5/1, more preferably 1/3 to 3/1, and still more preferably 1/1 to 2/1. When the ratio of the average thickness of the pressure-sensitive adhesive layer to the average thickness of the base material layer is within the above preferred range, excellent adhesiveness and removability of the pressure-sensitive adhesive sheet can be obtained. On the other hand, if the ratio is greater than 5/1, only the pressure-sensitive adhesive layer may remain on the adherend in the step of re-peeling the pressure-sensitive adhesive sheet. If the ratio is less than 1/5, the adhesive strength may be significantly reduced because the adhesive layer cannot follow when the surface of the adherend has irregularities or the like.

Method for forming substrate layer

The method for forming the substrate layer is not particularly limited, and may be appropriately selected from known methods according to the mechanical strength and the like required for the adhesive sheet, and examples thereof include a hot press method, a casting method by extrusion molding, a uniaxial stretching method, a sequential biaxial stretching method, a simultaneous biaxial stretching method, an inflation method, a tube method, a rolling method, a solution method and the like. These methods may be used alone in 1 kind, or 2 or more kinds may be used in combination. Among them, a casting method, an inflation method, a tube method, a calendering method, and a solution method by extrusion molding are preferable in terms of imparting appropriate flexibility and stretchability to the substrate layer.

The base material layer may be subjected to a surface treatment for the purpose of further improving adhesion to the adhesive layer.

The surface treatment method is not particularly limited, and may be appropriately selected from known methods within a range that does not impair the properties of the adhesive sheet, and examples thereof include a sand blast method, a surface polishing and rubbing method, a corona discharge treatment method, a chromic acid treatment method, a flame treatment method, a hot air treatment method, an ozone treatment method, an ultraviolet irradiation treatment method, an oxidation treatment method, and the like.

Other layers

The other layer in the adhesive sheet is not particularly limited and may be appropriately selected according to the purpose, and examples thereof include a primer layer, an antistatic layer, a nonflammable layer, a decorative layer, an electrically conductive layer, a thermally conductive layer, and a release layer.

Stress at 25% elongation of the adhesive sheet-

The stress at 25% elongation of the pressure-sensitive adhesive sheet is not particularly limited and may be appropriately selected depending on the purpose, and is preferably 0.15 to 82Mpa, more preferably 0.15 to 10Mpa, still more preferably 0.15 to 5Mpa, and particularly preferably 0.15 to 2 Mpa. When the stress at 25% elongation of the pressure-sensitive adhesive sheet is 0.15MPa to 82MPa, the pressure-sensitive adhesive sheet can have an appropriate adhesive strength, and can be relatively easily peeled off even when peeled off by elongation. On the other hand, if the stress at 25% elongation of the pressure-sensitive adhesive sheet is less than 0.15Mpa, the pressure-sensitive adhesive sheet may peel off when a load in the shear direction of the pressure-sensitive adhesive sheet is generated while fixing hard adherends to each other. Further, if the stress at 25% elongation of the pressure-sensitive adhesive sheet exceeds 82Mpa, the force required to elongate the pressure-sensitive adhesive sheet may become too large when the pressure-sensitive adhesive sheet is peeled.

The stress at 25% elongation of the pressure-sensitive adhesive sheet was measured as a stress value measured when the pressure-sensitive adhesive sheet was punched out into a dumbbell shape having a gauge length of 20mm and a width of 6mm, and the pressure-sensitive adhesive sheet was elongated at a tensile rate of 500 mm/min in the longitudinal direction under a measurement atmosphere of 23 ℃ and 50% RH using a Tensilon tensile tester (model: RTF-1210, manufactured by A & D), thereby causing 25% elongation.

Fracture point stress of adhesive sheet

The stress at break point of the pressure-sensitive adhesive sheet is not particularly limited, and may be appropriately selected depending on the purpose, and is preferably 1.5 to 100.0MPa, more preferably 5.0 to 50.0MPa, still more preferably 5.0 to 40.0MPa, and particularly preferably 5.0 to 35.0 MPa. If the stress at the break point of the pressure-sensitive adhesive sheet is within the above-described preferred range, the pressure-sensitive adhesive sheet can be prevented from breaking even when the pressure-sensitive adhesive sheet is peeled by stretching, and the load for stretching the pressure-sensitive adhesive sheet is not excessively excessive, so that the re-peeling operation by peeling becomes easy. On the other hand, if the stress at the fracture point of the pressure-sensitive adhesive sheet is less than 1.5MPa, the pressure-sensitive adhesive sheet may break when the pressure-sensitive adhesive sheet is peeled by stretching, and if it exceeds 100.0MPa, the pressure-sensitive adhesive sheet may not be sufficiently stretched and may not be peeled again when the pressure-sensitive adhesive sheet is peeled again by stretching. The force required to stretch and deform the pressure-sensitive adhesive sheet also depends on the thickness of the pressure-sensitive adhesive sheet, and for example, when the pressure-sensitive adhesive sheet is intended to be re-peeled by stretching the pressure-sensitive adhesive sheet having a large thickness and a high stress at break point, the pressure-sensitive adhesive sheet may not be sufficiently stretched and cannot be re-peeled.

The stress at break point of the pressure-sensitive adhesive sheet was measured by punching the pressure-sensitive adhesive sheet into a dumbbell shape having a gauge length of 20mm and a width of 6mm, and stretching the sheet in the longitudinal direction at a stretching speed of 500 mm/min using a Tensilon tensile tester (model: RTF-1210, manufactured by Kabushiki Kaisha A & D) under a measuring atmosphere of 23 ℃ and 50% RH.

Elongation at the breaking point of the adhesive sheet

The elongation at break of the pressure-sensitive adhesive sheet is not particularly limited, and may be appropriately selected depending on the purpose, and is preferably 500% to 2000%, more preferably 600% to 1800%, and still more preferably 800% to 1800%. When the elongation at break point of the pressure-sensitive adhesive sheet is 500% or more, even when the pressure-sensitive adhesive sheet is strongly adhered to an adherend, stress for stretching in the horizontal direction to the vertical direction with respect to the adherend surface does not become excessively large when the pressure-sensitive adhesive sheet is peeled off again, and the pressure-sensitive adhesive sheet can be easily peeled without being excessively elongated when peeled off. Further, if the elongation at break point is 2000% or less, the stretching distance in the horizontal direction to the vertical direction with respect to the surface to be adhered of the adherend is not excessively long when the pressure-sensitive adhesive sheet is peeled again, and the work can be performed in a small space. On the other hand, if the elongation at break point is less than 500%, peeling may not be performed along with breaking when the pressure-sensitive adhesive sheet is peeled off again by being pulled in the horizontal direction to the vertical direction with respect to the adherend surface, and if it exceeds 1300%, the pulling distance in the horizontal direction to the vertical direction with respect to the adherend surface may not become too long when the pressure-sensitive adhesive sheet is peeled off again, and thus workability may be deteriorated.

The elongation at break of the pressure-sensitive adhesive sheet was measured by punching the pressure-sensitive adhesive sheet into a dumbbell shape having a gauge length of 20mm and a width of 6mm, and stretching the sheet in the longitudinal direction at a stretching speed of 500 mm/min using a Tensilon tensile tester (model: RTF-1210, manufactured by Kagaku corporation A & D) under a measuring atmosphere of 23 ℃ and 50% RH.

Impact resistance of adhesive sheet

The pressure-sensitive adhesive sheet has excellent impact resistance. The impact resistance can be confirmed by, for example, the method described in "evaluation of impact resistance" in examples described later. In the evaluation of the impact resistance, the height of the impact core at which peeling or breakage of the pressure-sensitive adhesive sheet occurs may be appropriately selected within a range not impairing the effect of the present invention, and is preferably 30cm or more, more preferably 40cm or more, further preferably 50cm or more, and particularly preferably 60cm or more. If the height is less than 30cm, sufficient impact resistance cannot be obtained.

180 DEG peel adhesion of adhesive sheet

The 180 ° peel adhesion of the pressure-sensitive adhesive sheet is not particularly limited, and may be appropriately selected depending on the purpose, and is preferably 3N/20mm to 35N/20mm, more preferably 4N/20mm to 30N/20mm, and further preferably 5N/20mm to 25N/20 mm. When the 180 ° peel adhesion is within the above preferred range, the pressure-sensitive adhesive sheet has an appropriate adhesion without peeling or displacement from an adherend, and can be easily peeled off when the pressure-sensitive adhesive sheet is peeled off again by being stretched in the horizontal to vertical directions with respect to the surface to be adhered to the adherend.

The 180 ° peel adhesion of the adhesive sheet is measured according to JIS Z0237.

Shear adhesion of adhesive sheets

The pressure-sensitive adhesive sheet is not easily peeled off even when a load in the shear direction of the pressure-sensitive adhesive sheet is applied, and has excellent shear adhesion. The shear direction is not particularly limited as long as it is a direction perpendicular to the thickness direction of the adhesive sheet.

The shear adhesion of the pressure-sensitive adhesive sheet may be appropriately selected within the range not impairing the effects of the present invention, and is preferably 100N/4cm²Above, more preferably 120N/4cm²Above, it is more preferably 150N/4cm²Above, 200N/4cm is particularly preferable²The above. If the shear adhesion is aboveWithin the preferred range, the displacement in the shear direction when a stress is applied to an adherend fixed with the pressure-sensitive adhesive sheet can be suppressed.

The shear adhesion of the pressure-sensitive adhesive sheet can be confirmed, for example, by a method described in "measurement of shear adhesion" in examples described later.

Fracture adhesion of the adhesive sheet-

The pressure-sensitive adhesive sheet is less likely to peel even when a load is applied in a direction of fracture (also referred to as "thickness direction") of the pressure-sensitive adhesive sheet, and has excellent fracture adhesion. The pressure-sensitive adhesive sheet may be appropriately selected from those having a fracture adhesion strength within a range not impairing the effects of the present invention, and is preferably 80N/4cm²Above, more preferably 100N/4cm²The above is more preferably 120N/4cm²The above. When the fracture adhesion force is within the above preferred range, peeling can be suppressed when stress in the fracture direction is applied to an adherend fixed with the pressure-sensitive adhesive sheet.

The fracture adhesion of the psa sheet can be confirmed, for example, by the method described in "measurement of fracture adhesion" in the examples described below.

Average thickness of adhesive sheet

The average thickness of the pressure-sensitive adhesive sheet is not particularly limited, and may be appropriately selected depending on the average thickness of the pressure-sensitive adhesive layer and the base layer, and the like, and is preferably 15 μm to 800 μm, more preferably 30 μm to 540 μm, still more preferably 60 μm to 320 μm, and particularly preferably 70 μm to 250 μm.

In the present specification, the term "average thickness of the pressure-sensitive adhesive layer" means an average value of the thicknesses of 25 parts in total, which is obtained by cutting 5 parts of the pressure-sensitive adhesive sheet at 100mm intervals in the longitudinal direction and measuring the thickness of the pressure-sensitive adhesive layer at 5 parts at 100mm intervals in the width direction using a TH-104 paper/film thickness measuring machine (manufactured by stester SANGYO corporation).

Average width of adhesive sheet

The average width of the adhesive sheet is not particularly limited, and may be appropriately selected according to the kind of electronic component. The electronic component to be attached is a display, a speaker, a battery, or the like, and the average width of the adhesive sheet when fixing them can be appropriately adjusted according to the effectiveness of a display screen and an attachment space, and is preferably 1mm to 50mm, more preferably 1mm to 25mm, and further preferably 0.5mm to 10 mm.

In the present specification, the "average width of the adhesive sheet" refers to an average value of widths at 5 points in total, which is obtained by measuring the widths at 5 points in the longitudinal direction of the adhesive sheet at 100mm intervals using a known gauge such as a ruler (scale), a tape measure, or a convex surface.

Method for producing adhesive sheet

The method for producing the pressure-sensitive adhesive sheet is not particularly limited, and may be appropriately selected from known methods, and preferably includes a pressure-sensitive adhesive layer forming step, a base material layer forming step, and a laminating step, and further includes other layer forming steps as necessary. The adhesive layer may be formed by a multilayer simultaneous formation step of simultaneously performing the adhesive layer formation step and the base material layer formation step.

An adhesive layer forming step

The adhesive layer forming step is not particularly limited as long as the adhesive layer can be formed, and may be appropriately selected according to the purpose, and examples thereof include the same methods as those described in the above "method for forming an adhesive layer", and preferred embodiments thereof are also the same.

A substrate layer forming step

The substrate layer forming step is not particularly limited as long as the substrate layer can be formed, and may be appropriately selected according to the purpose, and examples thereof include the same methods as those described in the above "method for forming a substrate layer", and preferred embodiments thereof are also the same.

-lamination process-

The laminating step is a step of laminating the base material layer and the adhesive layer. The method of laminating the base layer and the adhesive layer is not particularly limited, and may be appropriately selected from known methods, and examples thereof include a method of laminating the base layer and the adhesive layer by pressing.

< method for producing electronic component >

The method for producing the electronic component is not particularly limited, and may be appropriately selected according to the purpose, and preferably includes a bonding step and a fixing step, and further includes other steps as necessary.

(attachment procedure)

The sticking step is a step of sticking the adhesive sheet to the first sticking target so that at least a part of one surface of the adhesive sheet is linear.

The adhesive sheet, the first object to be adhered, and the adhesive sheet to be adhered so that at least a part thereof is linear are as described above.

Procedure for fixation

The fixing step is a step 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 where at least 2 ends of the adhesive sheet are exposed from the second object to be attached.

The second attachment object and at least 2 end portions are exposed from the second attachment object as described above.

The electronic component includes an adhesive sheet which can be rapidly peeled off, is free from contamination by the adhesive after peeling, can be peeled off by stretching from the other end to the end even if the adhesive sheet is broken in the middle of peeling by stretching from one end, and has an appropriate adhesive force when used.

Examples

The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples at all.

In the production of the adhesive sheets (1) to (11) of production examples 1 to 11 below, the following compositions were used for the resin compositions (1) to (3) in the base layer and the adhesive compositions (1) to (8) in the adhesive layer.

< resin composition (1) >

As the resin composition (1), a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer (hereinafter, sometimes referred to as "SIS") was used, in which the structural unit derived from styrene represented by the following chemical formula (1) was 25% by weight, and the proportion of the styrene-isoprene copolymer with respect to the total amount of the resin composition (1) was 17% by weight.

[ chemical formula 2]

< resin composition (2) >

As the resin composition (2), an ester-based polyurethane compound (Mobilon Film MF100T, manufactured by Nisshinbo Textile Co., Ltd.) was used.

< resin composition (3) >

As the resin composition (3), a mixture (SIS) of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer was used, in which the structural unit derived from styrene represented by the above chemical formula (1) was 15 wt%, and the proportion of the styrene-isoprene copolymer with respect to the total amount of the resin composition (3) was 12 wt%.

Preparation example 1 preparation of adhesive composition (1)

A reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet, 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 part by weight of 4-hydroxybutyl acrylate and 200 parts by weight of ethyl acetate, and the temperature was raised to 65 ℃ while blowing nitrogen under stirring to obtain a mixture (1). Next, 4 parts by weight (solid content: 2.5% by weight) of a2, 2' -azobisisobutyronitrile solution previously dissolved in ethyl acetate was added to the mixture (1), and the mixture was held at 65 ℃ for 10 hours with stirring to obtain a mixture (2). Next, the mixture (2) was diluted with 98 parts by weight of ethyl acetate and filtered through a 200 mesh metal net to obtain an acrylic copolymer solution (1) having a weight average molecular weight of 160 ten thousand (in terms of polystyrene). Then, 5 parts by weight of a polymerized rosin ester-based tackifier resin (D-125, manufactured by Mitsui chemical Co., Ltd.) and 15 parts by weight of a petroleum tackifier resin (FTR (registered trademark) 6125, manufactured by Mitsui chemical Co., Ltd.) were mixed and stirred with 100 parts by weight of the acrylic copolymer solution (1), and ethyl acetate was added thereto to obtain a binder resin solution (1) having a solid content of 31% by weight. Then, 1 part by mass of carbon black (MA220, manufactured by Mitsubishi chemical corporation) and 1.3 parts by mass of a crosslinking agent (a trimethylolpropane adduct of toluene diisocyanate having an isocyanate group content of 7% by weight and a nonvolatile content of 40% by weight, manufactured by DIC) were added to 100 parts by weight of the binder resin solution (1), and the mixture was stirred and mixed until uniform, and then filtered through a100 mesh wire gauze to obtain a binder resin (1) having a solid content of 31.1% by weight.

Preparation example 2 preparation of adhesive composition (2)

Filler 1 (aluminum hydroxide, BW153, available from Nippon light Metal Co., Ltd., volume average particle diameter: 18 μm, particle size distribution (D) was added to 100 parts by weight of the solid content of the binder resin (1) obtained in preparation example 1₉₀/D₁₀): 12.3)30 parts by weight to obtain an adhesive composition (2).

The particle size distribution (D) of the filler particles₉₀/D₁₀) The particle size of the filler particles is measured by using a measuring instrument (Microtrac) using a laser diffraction scattering method, and the measured particle size is converted into a particle size distribution.

Preparation example 3 preparation of adhesive composition (3)

An adhesive composition (3) was prepared in the same manner as in preparation example 2, except that the kind and the addition amount of the filler in preparation example 2 were changed to those shown in table 1 below.

It should be noted that, in the following description,filler 2 was nickel powder (Type123, manufactured by Inco, volume average particle diameter: 11.9 μm), and its particle size distribution (D) was measured in the same manner as for filler 1₉₀/D₁₀) Was 4.2.

Preparation example 4 preparation of adhesive composition (4)

An 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.

The filler 3 was aluminum hydroxide (B303, manufactured by Nippon light Metal Co., Ltd., volume average particle diameter: 23 μm), and the particle size distribution (D) was measured by the same method as that for the filler 1₉₀/D₁₀) Was 18.5.

Preparation example 5 preparation of adhesive composition (5)

An adhesive composition (5) was prepared in the same manner as in preparation example 2, except that the type of the filler in preparation example 2 was changed to those shown in table 2 below.

The filler 4 was aluminum hydroxide (BE033, manufactured by Nippon light Metal Co., Ltd., volume average particle diameter: 3 μm), and the particle size distribution (D) was measured by the same method as that for the filler 1₉₀/D₁₀) Is 5.8.

Preparation example 6 preparation of adhesive composition (6)

An adhesive composition (6) was prepared in the same manner as in preparation example 2, except that the amount of the filler added in preparation example 2 was changed to the amount shown in table 2 below.

Preparation example 7 preparation of adhesive composition (7)

An adhesive composition (7) was prepared in the same manner as in preparation example 2, except that the amount of the filler added in preparation example 2 was changed to the amount shown in table 2 below.

Preparation example 8 preparation of 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 part by weight of 2, 2' -azobisisobutyronitrile as a polymerization initiator were dissolved in a solvent composed of 100 parts by weight of ethyl acetate, and polymerization was carried out at 70 ℃ for 12 hours to obtain an acrylic copolymer solution (2) having a weight average molecular weight of 200 ten thousand (in terms of polystyrene). Next, to 100 parts by weight of the acrylic copolymer solution (2), 25 parts by weight of glycerol ester of disproportionated rosin (super a100, seikagawa chemical industries co., ltd.), 5 parts by weight of pentaerythritol ester of polymerized rosin (PENSEL D135, seikagawa chemical industries co., ltd.), and 20 parts by weight of styrene-based petroleum resin (FTR (registered trademark) 6100, ltd.) were added, and ethyl acetate was added and uniformly mixed to obtain a binder solution (2) having a solid content of 31% by weight. Then, 1.3 parts by weight of an isocyanate-based crosslinking agent (Coronate L-45, product of Nippon Polyurethane Industry, 45% by weight of nonvolatile matter) was added to 100 parts by weight of the binder solution (2), and the mixture was stirred and mixed until uniform, thereby obtaining a binder resin (2) having a solid content of 31.1% by weight.

Next, filler 1 (aluminum hydroxide, BW153, available from Nippon light Metal Co., Ltd., volume average particle diameter: 18 μm, particle size distribution (D) was added to 100 parts by weight of the solid content of the obtained binder resin (2)₉₀/D₁₀): 12.3)30 parts by weight to obtain an adhesive composition (8).

Production example 1 production of adhesive sheet (1)

The adhesive composition (1) was applied to a release liner (Film Vina 75E-0010GT, manufactured by Tanson industries, Ltd., the same applies) with an applicator (applicator) so that the dried thickness became 25 μm, and dried at 80 ℃ for 3 minutes to prepare an adhesive layer.

Next, toluene was added to the resin composition (1), the mixture was stirred so as to be uniform, and the mixture was applied to a release liner with an applicator so that the thickness after drying became 100 μm, and dried at 60 ℃ for 5 minutes, thereby producing a base layer.

The release liner of the substrate layer was peeled off, the adhesive layer with the release liner peeled off was bonded to both surfaces of the substrate layer, and the laminate structure of the substrate layer and the adhesive layer was laminated under pressure of 0.2MPa to produce an adhesive sheet (1).

Production example 2 production of adhesive sheet (2)

A psa sheet (2) was produced in the same manner as in production example 1, except that the thickness of the base layer, the type of psa composition and the thickness of the psa layer were changed to the conditions described in table 1 in the production of the psa sheet (1) in production example 1.

Production example 3 production of adhesive sheet (3)

A psa sheet (3) was produced in the same manner as in production example 1, except that the type of psa composition was changed to the conditions described in table 1 in the production of the psa sheet (1) in production example 1.

Production example 4 production of adhesive sheet (4)

A psa sheet (4) was produced in the same manner as in production example 1, except that the type of psa composition was changed to the conditions described in table 1 in the production of the psa sheet (1) in production example 1.

Production example 5 production of adhesive sheet (5)

A psa sheet (5) was produced in the same manner as in production example 1, except that the type of resin composition in the base layer and the type of psa composition in the production of psa sheet (1) in production example 1 were changed to the conditions described in table 1.

Production example 6 production of adhesive sheet (6)

In the production of the psa sheet (1) of production example 1, a psa sheet (6) was produced in the same manner as in production example 1, except that the type of resin composition in the base layer, the thickness of the base layer, the type of psa composition and the thickness of the psa layer were changed to the conditions described in table 1.

Production example 7 production of adhesive sheet (7)

A psa sheet (7) was produced in the same manner as in production example 1, except that the type of psa composition was changed to the conditions described in table 2 in the production of the psa sheet (1) in production example 1.

Production example 8 production of adhesive sheet (8)

A psa sheet (8) was produced in the same manner as in production example 1, except that the thickness of the base layer, the type of psa composition and the thickness of the psa layer were changed to the conditions described in table 2 in the production of the psa sheet (1) in production example 1.

Production example 9 production of adhesive sheet (9)

A psa sheet (9) was produced in the same manner as in production example 1, except that the thickness of the substrate layer and the type of psa composition were changed to the conditions described in table 2 in the production of the psa sheet (1) in production example 1.

Production example 10 production of adhesive sheet (10)

A psa sheet (10) was produced in the same manner as in production example 1, except that the thickness of the substrate layer and the type of psa composition were changed to the conditions described in table 2 in the production of the psa sheet (1) in production example 1.

Production example 11 production of adhesive sheet (11)

A psa sheet (11) was produced in the same manner as in production example 1, except that the thickness of the substrate layer and the type of psa composition were changed to the conditions described in table 2 in the production of the psa sheet (1) in production example 1.

Stress, stress at break point and elongation at break point at 25% elongation of the base material layer in the adhesive sheets (1) to (11) of production examples 1 to 11; the adhesive layers in the adhesive sheets (1) to (11) of production examples 1 to 11 had a stress at 25% elongation, a stress at break, an elongation at break, and a volume ratio of filler; and the stress at 25% elongation, the stress at break point, the elongation at break point, the impact resistance, the 180 ° peel adhesion, the shear adhesion, and the split adhesion of the 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.

Measurement of stress at 25% elongation, stress at break point and elongation at break point of pressure-sensitive adhesive sheet or substrate layer

Each adhesive sheet or each substrate layer was punched out into a dumbbell shape having a reticle length of 20mm and a width of 6mm, and the adhesive sheet or each substrate layer was stretched at a stretching speed of 500 mm/min in the longitudinal direction under a measuring atmosphere of 23 ℃ and 50% RH using a Tensilon tensile tester (model: RTF-1210, manufactured by A & D), whereby the stress, the stress at break point and the elongation at break point at 25% elongation of each adhesive sheet or each substrate layer were measured.

Measurement of stress at 25% elongation of adhesive layer, stress at fracture Point, and elongation at fracture Point

Each adhesive layer was punched into a dumbbell shape having a reticle length of 20mm and a width of 10mm, and the stress, the stress at break point and the elongation at break point were measured at 25% elongation of each adhesive layer by stretching the adhesive layer in the longitudinal direction at a stretching speed of 300 mm/min under a measuring atmosphere of 23 ℃ and 50% RH using a Tensilon tensile tester (model: RTF-1210, manufactured by Kagaku corporation, A & D).

Measurement of volume ratio of Filler particles in adhesive layer

The volume ratio of the filler in each adhesive layer was calculated from the following formulas (1) to (3).

Weight of binder resin A (g)/density of binder resin A (g/cm)³) Volume of binder resin A (cm)³) … type (1)

Weight of filler particles B (g)/density of filler particles B (g/cm)³) Volume B (cm) of filler particles³) … type (2)

Volume B (cm) of filler particles³) Volume A (cm) of the binder resin³) + volume B (cm) of filler particles³) X 100 ═ volume ratio of filler particles (%) … formula (3)

The density A of the binder resin was set to 1.2g/cm³As the density B of the filler particles, the density of aluminum hydroxide was set to 2.42g/cm³The density of nickel was set to 8.90g/cm³And then calculated.

Evaluation of impact resistance

Each adhesive sheet was cut into pieces of 20mm in length and 5mm in width, and 2 pieces were prepared. As shown in FIG. 5A, the adhesive sheet 31 was attached in parallel to an acrylic plate 32 (length 50mm, width 50mm, thickness 2mm, acryl L, color: colorless, manufactured by MITSUISHI RAYON) at an interval of 40 mm. Next, as shown in fig. 5B, the acrylic plate 32 to which the adhesive sheet 31 was attached to the center of an ABS plate 33 (length 150mm, width 100mm, thickness 2mm, TAFACE R, manufactured by Sumitomo Bakelite, color tone: natural, without wrinkles), and the laminated structure of the acrylic plate 32, the adhesive sheet 31, and the ABS plate 33 was subjected to pressure contact by applying a load of 2kg to the laminated structure 1 time in a reciprocating manner using a roller, and then allowed to stand for 24 hours under an atmosphere of 40 ℃ and 50% RH to obtain a test piece.

As shown in FIG. 5C, an コ -shaped measuring table 34 (made of aluminum having a length of 150mm, a width of 100mm, a height of 45mm, and a thickness of 5 mm) was provided on a base of a DuPont impact TESTER (manufactured by TESTER SANGYO Co., Ltd.), and the test piece was placed thereon such that the acrylic plate 32 of the test piece faced downward. A stainless steel impact core (25 mm in diameter, 300g in weight) 35 was dropped from the ABS plate 33 side to the center of the ABS plate 33 in an atmosphere of 23 ℃ and 50% RH. At this time, while changing the height of the impact core 35 by 10cm from 10cm, the impact core 35 was dropped 5 times at intervals of 10 seconds per height, and the height at which peeling or breakage of the adhesive sheet in the test piece was confirmed was measured. When the pressure-sensitive adhesive sheet falls from 30cm or more, the pressure-sensitive adhesive sheet is not peeled or broken, and there is no problem in use.

Measurement of 180 ℃ peeling adhesion

The 180 ° peel adhesion of each adhesive sheet was measured according to JIS Z0237. Specifically, each pressure-sensitive adhesive sheet was cut into a length of 150mm and a width of 20mm, and one surface of the pressure-sensitive adhesive sheet was backed with a PET film having a thickness of 25 μm. Next, the other surface of the adhesive sheet was attached to a stainless steel plate (length 100mm, width 30mm, thickness 3mm) under conditions of atmosphere 23 ℃ and 50% RH, and the laminated structure of the adhesive sheet and the stainless steel plate was pressed and bonded by applying a load of 2kg to the laminated structure by 1 reciprocating press with a roller, and then allowed to stand for 1 hour under conditions of atmosphere 23 ℃ and 50% RH to obtain a test piece.

The pressure-sensitive adhesive sheet in the test piece was stretched at a stretching speed of 300 mm/min in a 180 DEG direction (horizontal direction) under conditions of an atmosphere of 23 ℃ and 50% RH using a Tensilon tensile tester (model: RTF-1210, manufactured by A & D), and the 180 DEG peel adhesion of the pressure-sensitive adhesive sheet was measured.

Measurement of shear adhesion

Each adhesive sheet was cut into a length of 20mm and a width of 20 mm. The surface of a clean stainless steel plate A (100 mm in length, 30mm in width, 3mm in thickness) which had been subjected to a grain polishing treatment with a water-resistant polishing paper (No. 360) was attached to one surface of the above adhesive sheet in an atmosphere of 23 ℃ and 50% RH so that the attachment area became 20 mm. times.20 mm. Next, a stainless steel plate B (100 mm in length, 30mm in width, 3mm in thickness) having a smooth surface and being cleaned by a water-resistant polishing paper (No. 360) and having a hairline polishing treatment was attached to the surface of the adhesive sheet opposite to the surface to which the stainless steel plate a was attached, and the pressure sheet was pressed and bonded to the laminated structure of the stainless steel plate a, the adhesive sheet, and the stainless steel plate B by applying a load of 5kg to the laminated structure 1 time in a reciprocating manner using a roller, and then allowed to stand for 24 hours under conditions of an atmosphere of 23 ℃ and 50% RH to prepare a test piece.

The stainless steel sheet B constituting the test piece was stretched at a stretching speed of 50 mm/min in the shear direction of the pressure-sensitive adhesive sheet by using a Tensilon tensile tester (model: RTF-1210, manufactured by Kagaku corporation) in a state where the stainless steel sheet A constituting the test piece was fixed under conditions of an atmosphere of 23 ℃ and 50% RH, and the shear adhesion was measured.

Determination of cleavage adhesion

Each adhesive sheet was cut into a length of 20mm and a width of 20 mm. A clean aluminum plate (alloy No. A1050, 50mm in length, 40mm in width, 3mm in thickness) having a smooth surface was bonded to one surface of the adhesive sheet in such a manner that the bonding area became 20 mm. times.20 mm under conditions of an atmosphere of 23 ℃ and 50% RH. Next, a clean and smooth aluminum plate (alloy No. a1050, length 50mm, width 40mm, thickness 3mm) was attached to the surface of the adhesive sheet opposite to the surface to which the aluminum plate was attached, and the laminate structure of the 2 aluminum plates and the adhesive sheet was pressure-bonded by applying a load of 5kg to the laminate structure by reciprocal pressing with a roller for 1 time, and then allowed to stand at 23 ℃ and 50% RH in an atmosphere for 24 hours to obtain a test piece.

The aluminum plate B constituting the test piece was stretched at a stretching rate of 50 mm/min in the fracture direction (thickness direction) of the adhesive sheet using a Tensilon tensile tester (model: RTF-1210, manufactured by Kagaku corporation A & D) in a state where the aluminum plate A constituting the test piece was fixed under conditions of an atmosphere of 23 ℃ and 50% RH, and the fracture adhesion was measured.

[ Table 1]

*1: the addition amount of the filler particles means an addition amount (part by weight) of the filler particles with respect to 100 parts by weight of the adhesive composition.

[ Table 2]

(test examples 1 to 11)

The adhesive sheets (1) to (11) of production examples 1 to 11 were each cut into a width of 10mm and a length of 60mm, and as shown in fig. 6A, one surface 41a of the adhesive sheet 41 was linearly attached to a clean and smooth-surfaced aluminum plate 42 (alloy No. a1050, length of 50mm, width of 40mm, thickness of 3 mm). Next, the other surface 41b of the adhesive sheet 41 was attached to a clean and smooth-surfaced acrylic plate 43 (length 40mm, width 40mm, thickness 3mm, acryl L, color: colorless, manufactured by MITSUBISHI RAYON Co., Ltd.). At this time, both ends (the first holding portion a and the second holding portion B) in the longitudinal direction (extending direction) of the adhesive sheet 41 were attached in a state where the width and the length of each of the acrylic plates 43 were exposed to 10mm and 10mm, respectively. Next, the laminated structure of the aluminum plate 42, the adhesive sheet 41, and the acrylic plate 43 was pressed and bonded to each other 1 time by reciprocal pressing with a roller while applying a load of 5kg, and then allowed to stand for 3 days under conditions of an atmosphere of 23 ℃ and 50% RH.

The adhesive sheets used in test examples 1 to 11 are shown in table 3 below. In table 3 below, this attachment mode is represented by "X".

(comparative test examples 1 to 11)

The adhesive sheets (1) to (11) of production examples 1 to 11 were each cut into a width of 10mm and a length of 70mm, and one surface 44a of the adhesive sheet 44 was stuck to a clean and smooth-surfaced aluminum plate 42 (alloy No. a1050, length of 50mm, width of 40mm, thickness of 3mm) in a straight line as shown in fig. 6C. Next, the other surface 44b of the adhesive sheet 44 was attached to a clean and smooth-surfaced acrylic plate 43 (length 40mm, width 40mm, thickness 3mm, acryl L, color: colorless, manufactured by MITSUBISHI RAYON Co., Ltd.). At this time, one end (gripping portion a') of the adhesive sheet 44 in the longitudinal direction (extending direction) is attached from one end of the acrylic plate 43 in a state where the width is 10mm and the length is 10 mm. Next, the laminated structure of the aluminum plate 42, the adhesive sheet 44, and the acrylic plate 43 was pressed and bonded to each other 1 time by reciprocal pressing with a roller while applying a load of 5kg, and then allowed to stand for 3 days under conditions of an atmosphere of 23 ℃ and 50% RH.

The adhesive sheets used in comparative test examples 1 to 11 are shown in table 3 below. In table 3 below, this attachment mode is represented by "Y".

Evaluation of Redissociability 1

The horizontal removability of each laminate structure of test examples 1 to 11 and comparative test examples 1 to 11 was evaluated by the following method.

The first grip portion A and the second grip portion B of each of the pressure-sensitive adhesive sheets used in test examples 1 to 11 and the grip portion A' of each of the pressure-sensitive adhesive sheets used in comparative test examples 1 to 11 were respectively pulled at a pull rate of 300 mm/min using a Tensilon tensile tester (model: RTF-1210, manufactured by Kogyo A & D) in a direction of 180 DEG (horizontal direction) (the pull direction p in FIG. 6A or the pull direction p in FIG. 6C) under an atmosphere of 23 ℃ and 50% RH, and a tensile peel test was performed. The above-mentioned elongation peeling test was carried out 5 times for the above-mentioned tensile peeling test in the horizontal direction (n-5) and 5 times for the above-mentioned tensile peeling test in the vertical direction (n-5), and the total of 10 times was carried out. In the case of the application form X of test examples 1 to 11, after being pulled and peeled from one of the first grip portion a and the second grip portion B, the other was elongated and peeled from the grip portions, and the test was conducted 1 time (n is 1).

In the tensile peel test, the degree of adhesive remaining on an adherend (acrylic plate) after peeling of the adhesive sheet was visually confirmed, and evaluation was performed based on the following evaluation criteria. The pressure-sensitive adhesive sheet was broken during the stretch peeling and the detachability between the aluminum plate and the acrylic plate was evaluated based on the following evaluation criteria. The evaluation results are shown in table 3 below.

[ evaluation criteria for adhesive residue ]

O: no adhesive residue

X: with residues of adhesive

In the evaluation criteria for the residue of the adhesive, "o" is a case where there is no problem in use.

As an example of the degree of adhesive remaining in the above-described elongation peeling test, fig. 7A shows the appearance of the acrylic sheet after the horizontal direction stretch peeling of test example 1, and fig. 7B shows the appearance of the acrylic sheet after the horizontal direction stretch peeling of comparative test example 1. In fig. 7A, "410" indicates a site to which the adhesive sheet is attached, and "p" indicates a stretching direction of the adhesive sheet. In fig. 7B, "440" indicates a portion to which the adhesive sheet is attached, and "p" indicates a stretching direction of the adhesive sheet. As a result, it was found that no adhesive remained when the pressure-sensitive adhesive sheet was attached in the attachment method X, whereas a significant adhesive remained when the pressure-sensitive adhesive sheet was attached in the attachment method Y.

[ evaluation criteria for cracking ]

Very good: the number of cracks was 0

O: the number of the cracks is 1 to 2

Δ: the number of the cracks is 3 to 4

X: the number of ruptures was 5

In the evaluation criteria for cracking, the "o" and "very good" are the cases where there is no problem in use.

[ evaluation criteria for resolution ]

Very good: the number of times of disintegration was 5

O: the number of times of disintegration is 3 to 4

Δ: the number of times of disintegration is 1 to 2

X: the number of times of disintegration was 5

In the evaluation criteria for the disaggregation, ". smallcircle" and ". circleincircle" are cases where there is no problem in use.

[ Table 3]

As is clear from the results in table 3, in all cases where the application method of test examples 1 to 11 is X, there is no contamination by the adhesive after peeling, and even if the tape breaks during the elongation peeling from one end portion (first grip portion), the tape can be elongated and peeled from the other end portion (second grip portion) to the end. On the other hand, in the case of Y as the sticking method of comparative test examples 1 to 11, even if the stretch peeling was possible, the adhesive remained on the adherend, and in the case of breaking in the middle of the stretch peeling from one end portion, the aluminum plate and the acrylic plate could not be peeled off to the end, and could not be disassembled.

Evaluation of Re-peelability 2

With respect to each laminate structure of test examples 1 to 11, the removability in the vertical direction was evaluated by the following method.

In the above-mentioned evaluation 1 of removability, a tensile peeling test was carried out in the same manner as in the above-mentioned evaluation 1 of removability, except that the tensile conditions of the first holding part a and the second holding part B of each of the pressure-sensitive adhesive sheets used in test examples 1 to 11 were changed from the 180 ° direction (horizontal direction) (direction indicated by the tensile direction p in fig. 6A) to the 90 ° direction (vertical direction) (direction indicated by the tensile direction p in fig. 6B) with respect to the sticking surface of the pressure-sensitive adhesive sheet, and the degree of adhesive remaining on the adherend (acrylic plate) after peeling of the pressure-sensitive adhesive sheet, cracking of the pressure-sensitive adhesive sheet at the time of tensile peeling, and detachability of the aluminum plate and the acrylic plate were evaluated in the same manner as in the above-mentioned evaluation 1 of removability. The evaluation results are shown in table 4 below.

[ Table 4]

From the results in table 4, it is clear that the adhesive sheets (2) to (11) of test examples 2 to 11 were free from contamination by the adhesive after peeling even when they were peeled by stretching in the direction of 90 ° (perpendicular direction) with respect to the sticking surface of the adhesive sheet.

Examples of the embodiment of the present invention include the following embodiments.

<1> an electronic component, characterized by comprising an adhesive sheet, one surface of which is bonded to a first bonding object so that at least a part of the adhesive sheet is linear, the other surface of which is bonded to a second bonding object, and which is bonded to the second bonding object in a state in which at least 2 ends are exposed from the second bonding object.

<2> the electronic component according to <1>, wherein at least one of the first attachment subject and the second attachment subject is a recovery member.

<3> the electronic component according to any one of <1> to <2>, wherein the recovery member is at least one of a display glass and a battery.

<4> the electronic component according to any one of <1> to <3>, wherein when a width of an area of the adhesive sheet to be attached in the electronic component is X (cm) and a length of the area to be attached is Y (cm), a ratio (X/Y) of the width of the area to the length of the area to be attached is 1/100000 to 1/1.

Industrial applicability

The electronic component includes an adhesive sheet which can be rapidly peeled off, is free from contamination by the adhesive after peeling, can be peeled off by stretching from one end to the end even if the adhesive sheet is broken in the middle of peeling by stretching from the other end, and has an appropriate adhesive force when used.

Description of the reference numerals

1: handle projecting piece

2: adhesive area

3: terminal part

4: first adhesive region

5: second adhesive region

6: third adhesive region

7: front end part

21: adhesive sheet

21 a: one surface of the adhesive sheet 21

21 b: the other surface of the adhesive sheet 21

22: first attaching object

23: second attaching object

31: adhesive sheet

32: acrylic plate

33: ABS plate

34: コ font testing table

35: impact core

41: adhesive sheet

41 a: one surface of the adhesive sheet 41

41 b: the other surface of the adhesive sheet 41

42: first attaching object

43: second attaching object

44: adhesive sheet

61: adhesive sheet

61 a: one surface of the adhesive sheet 61

61 b: the other surface of the adhesive sheet 61

62: rear base

63: battery with a battery cell

71: adhesive sheet

71 a: one surface of the adhesive sheet 71

71 b: the other surface of the adhesive sheet 71

72: rims

73: display device

410: part to which adhesive sheet is attached

440: part to which adhesive sheet is attached

A: a first holding part

B: second holding part

C: third holding part

D: the fourth holding part

A': gripping part

p: direction of stretching

Claims

1. An electronic component is characterized by comprising an adhesive sheet, wherein one surface of the adhesive sheet is attached to a first attaching object in a manner that at least a part of the adhesive sheet is linear, the other surface of the adhesive sheet is attached to a second attaching object, and the adhesive sheet is attached to the second attaching object in a state that at least 2 ends of the adhesive sheet are exposed from the second attaching object.

2. The electronic component according to claim 1, wherein at least any one of the first attachment object and the second attachment object is a recovery part.

3. The electronic component according to claim 1 or 2, wherein the recovery 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 a width of an attachment area of an adhesive sheet in the electronic component is X and a length of the attachment area is Y, a ratio of the width of the attachment area to the length of the attachment area, that is, X/Y is 1/100000 to 1/1, wherein a unit of X and Y is cm.