JP6414942B2 - Adhesive sheet - Google Patents

Description

The present invention relates to a wide residues or peelable both sides pressure-sensitive adhesive sheet without destruction by stretching in the bond plane.

  For example, in portable electronic devices such as smartphones and mobile phones, an adhesive sheet is used for fixing a battery pack and a casing. And when taking out a battery pack, an adhesive sheet is pulled and it peels by the extending | stretching. The pressure-sensitive adhesive sheet for such use is required to have performance such as no residue (pressure-sensitive adhesive) remaining at the time of peeling and no destruction of the sheet.

  As an adhesive sheet that can be peeled by stretching, for example, Patent Document 1 discloses a specific adhesive film piece in which the adhesiveness of the adhesive layer disappears when the film is stretched, and Patent Document 2 discloses a specific block copolymer. An adhesive sheet strip comprising a styrene block copolymer and an acid-modified and / or acid-modified elastomer is disclosed in US Pat. Patent Document 4 discloses an adhesive tape having a specific backing layer and a pressure-sensitive adhesive layer.

  However, the pressure-sensitive adhesive sheet that can be peeled off by conventional stretching has room for further improvement in performance, such as no residue remaining at the time of peeling, and no destruction of the sheet.

Japanese Patent No. 3827247 JP 2004-162065 A Japanese Patent Laid-Open No. 2003-041217 Special table 2012-528919 gazette

  An object of the present invention is to provide a pressure-sensitive adhesive sheet in which no residue (pressure-sensitive adhesive) remains at the time of peeling by stretching and the sheet is not broken.

  As a result of intensive studies to achieve the above object, the present inventors have found that it is very effective to use a specific urethane resin as the base polymer of the base material, and have completed the present invention.

That is, the present invention has an adhesive layer on both surfaces of the base material, a peelable adhesive sheet by stretching, the substrate is, the softening point conforming to JIS K 7196 is at 60 ° C. or less low crystallinity It is a pressure-sensitive adhesive sheet obtained by using a linear polyester-based polyurethane resin as a base polymer.

  In the present invention, since a specific urethane resin is used as the base polymer of the base material, appropriate flexibility, stretchability, and tensile strength are exhibited. As a result, the base material does not break even during peeling due to stretching. It becomes a pressure sensitive adhesive sheet.

<Base material>
The base material used in the present invention is characterized in that a polyurethane resin having a softening point of 60 ° C. or lower is obtained as a base polymer. Specifically, the softening point measured in accordance with JIS K 7196 “Method for testing softening temperature by thermomechanical analysis of thermoplastic film and sheet” is 60 ° C. or less, and preferably 30 ° C. to 60 ° C. By using a polyurethane resin with a relatively low softening point in this way, the substrate exhibits appropriate flexibility, stretchability, and tensile strength. As a result, the substrate does not break even during peeling due to stretching, and reworkability It becomes an excellent adhesive sheet.

  In Examples described later, a Pull test and a reworkability test were performed. These tests are tests for evaluating the performance that allows easy peeling without any problem when peeling the adhesive sheet in the bonded state. This invention provides the adhesive sheet which has the performance (rework property) that a base material does not destroy in such a test and there is no residue of an adhesive. For example, when taking out parts such as a battery pack of an information portable terminal such as a smartphone or a mobile phone, it is necessary to pull one end of the pressure-sensitive adhesive sheet and peel it off by stretching. At that time, it is desirable that the pressure-sensitive adhesive sheet can be easily peeled off and no residue such as a pressure-sensitive adhesive remains at the peeled portion. Here, if the flexibility and stretchability of the substrate is high, the pressure-sensitive adhesive layer within the adhesive surface is stretched uniformly and uniformly over a wide range by pulling one end of the pressure-sensitive adhesive sheet, and the adhesive strength is moderately reduced. As a result, no residue (adhesive) remains, and peeling can be easily performed. However, if the tensile strength of the substrate is low, the substrate may be destroyed. On the other hand, since a polyurethane resin having specific physical properties is used in the present invention, these problems are less likely to occur.

  The glass transition temperature (Tg) of the polyurethane resin is preferably −30 ° C. or higher, more preferably −30 ° C. to −10 ° C. Thus, by using a polyurethane resin having a relatively high Tg, the strength does not decrease so much even if the base material has high flexibility and stretchability. As a result, the base material does not break even when peeled by stretching, An adhesive sheet with excellent reworkability.

  The weight average molecular weight (Mw) of the polyurethane resin is preferably 100,000 to 300,000, more preferably 100,000 to 200,000. Thus, the strength does not decrease so much even if the base material has a high flexibility and stretchability by using a polyurethane resin having a relatively high Mw, and as a result, the base material does not break even when peeling by stretching, An adhesive sheet with excellent reworkability.

  The polyurethane resin is usually a polymer of a polyol and a polyfunctional isocyanate, and is a resin containing a soft segment composed of a polyol monomer unit and a hard segment composed of a polyfunctional isocyanate compound or a low molecular glycol monomer unit. .

  The polyol used for the polyurethane resin is a compound having two or more hydroxyl groups. The number of hydroxyl groups of the polyol is preferably 2 to 3, more preferably 2. As the polyol, for example, polyester polyol, polyether polyol, polycaprolactone polyol, polycarbonate polyol, or castor oil-based polyol can be used. Two or more polyols may be used in combination.

  The polyester polyol is obtained, for example, by an esterification reaction between a polyol component and an acid component. Specific examples of the polyol component include ethylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl- 1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 2- Examples include methyl-1,8-octanediol, 1,8-decanediol, octadecanediol, glycerin, trimethylolpropane, pentaerythritol, hexanetriol, and polypropylene glycol. Specific examples of the acid component include succinic acid, methyl succinic acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, dimer acid, 2-methyl-1 , 4-cyclohexanedicarboxylic acid, 2-ethyl-1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid Examples include acids and acid anhydrides thereof.

  Polyether polyols start with, for example, water, low molecular weight polyols (eg propylene glycol, ethylene glycol, glycerin, trimethylolpropane, pentaerythritol), bisphenols (eg bisphenol A) or dihydroxybenzenes (eg catechol, resorcin, hydroquinone) As an agent, it can be obtained by addition polymerization of alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide. Specific examples include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

  Specific examples of the polycaprolactone polyol include ring-opening polymers of cyclic ester monomers such as ε-caprolactone and σ-valerolactone.

Specific examples of the polycarbonate polyol, the above polyol component with phosgene and the polycondensation reaction is allowed polycarbonate polyols obtained; and above polyol component, dimethyl carbonate, diethyl carbonate, Jipurobiru, diisopropyl carbonate, dibutyl carbonate, ethylbutyl carbonate, Polycarbonate polyol obtained by transesterification with carbonic acid diesters such as ethylene carbonate, propylene carbonate, diphenyl carbonate, dibenzyl carbonate; copolymer polycarbonate polyol obtained by using two or more of each of the above polyol components; A polycarbonate polyol obtained by esterification reaction of a carboxyl group-containing compound with each of the above polycarbonate polyols and a hydroxyl group-containing compound Polycarbonate polyol obtained by etherification reaction; polycarbonate polyol obtained by transesterification of each of the above polycarbonate polyol and ester compound; polycarbonate polyol obtained by transesterification of each of the above polycarbonate polyol and hydroxyl group-containing compound; And polyester polycarbonate polyols obtained by polycondensation reaction of the above polycarbonate polyols and dicarboxylic acid compounds; copolymer polyether polycarbonate polyols obtained by copolymerization of the above polycarbonate polyols and alkylene oxides.

  The castor oil-based polyol is obtained, for example, by reacting castor oil fatty acid with each of the above polyol components (for example, polypropylene glycol).

  As a polyfunctional isocyanate compound used for the polyurethane resin, for example, a polyfunctional aliphatic isocyanate compound, a polyfunctional alicyclic isocyanate compound, or a polyfunctional aromatic isocyanate compound can be used. Trimethylolpropane adducts of these compounds, burettes reacted with water, and trimers having an isocyanurate ring can also be used. Two or more polyfunctional isocyanate compounds may be used in combination.

Specific examples of the polyfunctional aromatic diisocyanate compound, phenylene diisocyanate, 2,4 Torirenjiiso shea Aneto, 2,6-tolylene diisocyanate, 2,2 'single-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4, Examples thereof include 4′-toluidine diisocyanate, 4,4′-diphenyl ether diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, and xylylene diisocyanate.

  The polyurethane resin is obtained by curing the composition containing the polyol and the polyfunctional isocyanate compound described above. In particular, a low crystalline linear polyester polyurethane resin is preferable, and a hexanediol copolyester polyurethane resin and a polytetramethylene glycol polyurethane resin are more preferable.

  Examples of commercially available polyurethane resins include Desmocol (registered trademark) manufactured by Sumika Bayer Urethane Co., Ltd., and Nipporan (registered trademark) manufactured by Nippon Polyurethane Industry Co., Ltd. Specifically, the low crystallinity is obtained in accordance with JIS K 6253 “Rubber Hardness Standard” by preparing a resin test piece having a film thickness of 6 mm and melting the test piece at 100 ° C. for 30 minutes to 23 ± 2 ° C. and relative humidity. This can be determined by measuring the time from when the resin is left in an environment of 50 ± 5% until the hardness of the resin reaches Shore A90. Specifically, a resin having a time period of 72 hours or longer until Shore A 90 is reached can be referred to as a low crystalline resin.

  Furthermore, in this invention, it is preferable to use a crosslinking agent from a viewpoint of the physical property improvement of a base polymer. As the crosslinking agent, for example, a metal chelate-based, metal alkoxide-based, epoxy-based, isocyanate-based, aziridine-based, polyfunctional acrylate, carbodiimide-based, oxazoline-based, or melamine-based crosslinking agent can be used. Of these, isocyanate-based crosslinking agents are preferred.

  You may add another component to the resin composition for comprising a base material. Specifically, for example, catalysts, other resin components, foaming agents, tackifiers, inorganic fillers, organic fillers, metal powders, pigments, foils, softeners, plasticizers, anti-aging agents, heat dissipation agents A conductive agent, an antioxidant, an ultraviolet absorber, a light stabilizer, a surface lubricant, a leveling agent, a corrosion inhibitor, a heat stabilizer, a polymerization inhibitor, a lubricant, and a solvent can be added.

  The thickness of the substrate is preferably 20 to 200 μm, more preferably 50 to 150 μm.

<Adhesive layer>
Pressure-sensitive adhesive layer is a layer comprising the pressure-sensitive adhesive composition is provided on both surfaces of the substrate. The pressure-sensitive adhesive composition is not particularly limited as long as it contains a pressure-sensitive adhesive that does not impair the effects of the present invention. For example, an emulsion-based adhesive, a solvent-based adhesive, an oligomer-based adhesive, a solid adhesive, and a hot-melt adhesive can be used. The pressure-sensitive adhesive layer is particularly preferably made of a pressure-sensitive pressure-sensitive adhesive.

  Examples of the type of pressure-sensitive adhesive include acrylic pressure-sensitive adhesive, rubber-based pressure-sensitive adhesive (natural rubber-based pressure-sensitive adhesive or synthetic rubber-based pressure-sensitive adhesive), silicone-based pressure-sensitive adhesive, polyester-based pressure-sensitive adhesive, urethane-based pressure-sensitive adhesive, and polyamide-based pressure-sensitive adhesive. Agents, epoxy adhesives, vinyl alkyl ether adhesives, and fluorine adhesives. Two or more pressure-sensitive adhesives may be used in combination. Among these, an acrylic pressure-sensitive adhesive is preferable. The acrylic pressure-sensitive adhesive is generally a composition containing as a main component a compound obtained by curing an acrylic copolymer [(meth) acrylic acid ester copolymer etc.] as a base polymer with a crosslinking agent. For example, a tackifier, a plasticizer, a filler, and a colorant can be added to the adhesive.

The pressure-sensitive adhesive layer can be formed, for example, by applying a pressure-sensitive adhesive on a substrate and causing a crosslinking reaction by heating or ultraviolet irradiation. Further, for example, by applying an adhesive to the release paper or other on the film by crosslinking reaction to form an adhesive layer by heating or ultraviolet irradiation, it may be bonded to the pressure-sensitive adhesive layer on both surfaces of the substrate. For the application of the pressure-sensitive adhesive, for example, a coating device such as a roll coater, a die coater, or a lip coater can be used. When heating after application, the solvent in the pressure-sensitive adhesive composition can be removed together with the crosslinking reaction by heating.
<Adhesive sheet>

Pressure-sensitive adhesive sheet of the invention, or a base material as described, that have a pressure-sensitive adhesive layer provided on both surfaces of the substrate. The thickness of the pressure-sensitive adhesive sheet is preferably 30～400Myuemu, more preferably 50 to 300 [mu] m.

One feature of the pressure-sensitive adhesive sheet of the present invention is that there is no destruction of the sheet upon peeling by stretching. Specifically, it is preferable that the substrate is not broken in the following Pull test.
[Pull test]
A stainless steel plate is attached to one surface of a pressure-sensitive adhesive sheet having a width of 10 mm and a length of 45 mm, and a polycarbonate plate is attached to the other surface, and a 90-degree peel test according to JIS Z 0237 is performed 24 hours later.

The pressure-sensitive adhesive sheet of the present invention is also characterized by excellent tensile strength and elongation. Specifically, in the following tensile test, it is preferable that the tensile strength is 20 N / mm ² or more and the elongation is 500% or more.
[Tensile test]
An adhesive sheet having a width of 10 mm and a length of 100 mm is fixed to a tensile tester set at a chuck interval of 30 mm, pulled at a speed of 300 mm / min, tensile strength at break (N / mm ² ) and elongation (%) Measure.

  Hereinafter, the present invention will be described in more detail with reference to examples. In the following description, “part” means “part by mass”.

<Preparation of acrylic pressure-sensitive adhesive composition>
In a reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas introduction tube, 70 parts of 2-ethylhexyl acrylate, 4.9 parts of n-butyl acrylate, 10 parts of acrylic acid, 0.1 part of 4-hydroxybutyl acrylate 2 parts of vinyl acetate, 100 parts of ethyl acetate, 0.1 part of n-dodecanethiol as a chain transfer agent and 0.1 part of lauryl peroxide as a radical polymerization initiator were charged. Nitrogen gas was sealed in the reactor, and the polymerization reaction was carried out at 68 ° C. for 3 hours and then at 78 ° C. for 3 hours under a nitrogen gas stream while stirring.

  Then, it cooled to room temperature and added ethyl acetate. As a result, an acrylic copolymer having a solid content concentration of 30%, a theoretical Tg of 62.3 ° C., and a weight average molecular weight of 1.1 million was obtained. Next, 0.07 part of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate (registered trademark) L) and an appropriate amount of an organic solvent are added to 100 parts of this acrylic copolymer and stirred with a stirrer until uniform. And obtained an acrylic pressure-sensitive adhesive composition

<Preparation of polyurethane resin composition>
A low crystalline linear polyester-based polyurethane resin solution and an isocyanate-based crosslinking agent (product name: Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) were added and stirred with a stirrer until uniform dispersion to obtain a polyurethane resin composition. Table 1 shows the type and amount (parts) of the polyurethane resin and the amount (parts) of the crosslinking agent.

<Examples 1-3 and Comparative Examples 1-2>
The above polyurethane resin composition is applied to one side of a release paper having a silicone release agent formed on both sides, dried at 50 ° C. for 2 minutes + 100 ° C. for 2 minutes to remove the solvent, and a resin substrate (thickness 70 μm) Got.

  The above-mentioned acrylic pressure-sensitive adhesive composition was applied to a release paper subjected to a double-sided silicone release treatment and dried to form a pressure-sensitive adhesive layer. And this adhesive layer was bonded together to the base material. Furthermore, the pressure-sensitive adhesive layer was bonded to the opposite surface in the same manner. Thereafter, aging was carried out at 40 ° C. for 3 days to complete the curing reaction of the pressure-sensitive adhesive layer, thereby obtaining a double-sided pressure-sensitive adhesive sheet having a thickness of about 100 μm (the thickness of each pressure-sensitive adhesive layer was about 15 μm).

  For each pressure-sensitive adhesive sheet obtained as described above, physical properties and performance evaluation were performed according to the following methods. The results are shown in Table 1.

[Softening point of polyurethane resin]
The softening point of the polyurethane resin was measured according to JIS K 7196 “Testing method for softening temperature of thermoplastic film and sheet by thermomechanical analysis”.

[Glass transition temperature (Tg) of polyurethane resin]
Using a viscoelasticity tester for dynamic viscoelasticity measurement, a 0.2 mm thick linear polyester polyurethane resin is sandwiched between parallel plates of the measurement unit of the tester, and the frequency is 1 Hz to −100 ° C. to 200 ° C. The storage elastic modulus (G ′) and loss elastic modulus (G ″) up to 0 ° C. were measured. Further, the glass transition temperature (Tg) was determined from Tan δ.

[Weight average molecular weight of polyurethane resin (Mw)]
The weight average molecular weight (Mw) of the molecular weight in terms of standard polystyrene of the acrylic copolymer was measured by the GPC method using the following measuring apparatus and conditions.
・ Device: LC-2000 series (manufactured by JASCO Corporation)
-Column: Shodex KF-806M x 2 and Shodex KF-802 x 1-Eluent: Tetrahydrofuran (THF)
・ Flow rate: 1.0 mL / min ・ Column temperature: 40 ° C.
・ Injection volume: 100 μL
・ Detector: Refractometer (RI)
Measurement sample: A linear polyester polyurethane resin dissolved in THF to prepare a solution having a linear polyester polyurethane resin concentration of 0.5% by weight, and dust was removed by filtration through a filter.

[Pull test]
A stainless steel plate is attached to one side of a pressure-sensitive adhesive sheet having a width of 10 mm and a length of 45 mm, and a polycarbonate plate is attached to the other side. After 90 hours, a 90-degree peel test in accordance with JIS Z 0237 is performed. evaluated.
“◯”: The base material was not destroyed and there was no adhesive residue.
“X”: The substrate was broken.

[Narrow width workability]
While maintaining the state that the double-sided PSA sheet is shredded into 10 pieces with a width of 5 mm and a length of 125 mm (that is, each sliced PSA sheet is kept adjacent to the shredded state), 65 ° C., It was left for 1 day in an atmosphere of 80% RH. Then, the release paper was peeled in the direction of 180 degrees for each one, the adhesion with the adjacent portion was visually confirmed, and the narrow width workability was evaluated according to the following criteria.
“◯”: There was almost no adhesion with the adjacent part, and it was able to peel without peeling off the adjacent part.
"X": There was remarkable adhesion in the adjacent part, and the adjacent part was peeled off at the same time.

[Reworkability]
The double-sided PSA sheet was attached to a stainless steel plate, a 90-degree peel test was performed after 30 minutes, and the following criteria were evaluated.
“◯”: The base material was not destroyed and there was no adhesive residue.
“X”: The substrate was broken.

[Load resistance]
The double-sided PSA sheet was cut to a size of 25 × 25 mm, and one release paper was peeled off. The double-sided PSA sheet was bonded to the test hook plate, and then the other release paper was peeled off and bonded to the polycarbonate plate. A load of 700 gf was applied to the hook and held at 85 ° C. for 60 minutes, and load resistance was evaluated according to the following criteria.
“◯”: The hook did not fall for 60 minutes.
"X": The hook fell within 60 minutes.

[Shock resistance]
Double-sided adhesive sheet is cut into a frame of 0.8mm width and 50x45mm, one release paper is peeled off and bonded to a 2mm thick glass plate, the other release paper is peeled off and a 3mm thick polycarbonate plate Pasted together. Then, using an autoclave, pressure treatment was performed at 23 ° C. and 0.5 MPa for 1 hour. Furthermore, the whole weight was adjusted to 250 g using a SUS plate, and placed in an environment of −20 ° C. for 1 hour or longer. And it dropped on the concrete floor, passing through a pipe | tube so that a test board might become a perpendicular direction from the height of 1.5 m, and the frequency | count of the fall which a glass plate peels was measured.

[Waterproof]
The double-sided PSA sheet is cut into a frame with a width of 0.8 mm and a size of 40 x 50 mm, one release paper is peeled off and bonded to a 2 mm thick glass plate, and the other release paper is peeled off to remove a 2 mm thick glass. The plates were bonded together. The sample was reciprocated once by a 2 kg roller. After that, it was submerged in accordance with the IPX7 test method of the waterproof standard IEC “International Electrotechnical Commission” 60529: 2001 [equivalent standard: JIS C 0920: 2003 “Special Protection for Electrical Equipment and Appliances (IP Code)”]. It was evaluated whether or not the waterproof property of the standard was satisfied (the item described as “IPX7” in Table 1 satisfies the standard).

[Tensile strength / elongation]
The double-sided PSA sheet is cut out to a width of 10 mm and a length of 100 mm, fixed to a tensile tester with a chuck interval set to 30 mm, and pulled at a speed of 300 mm / min to obtain a tensile strength (N / mm ² ) and elongation at break (N / mm ² ). %).

The abbreviations in Table 1 indicate the following compounds.
[UE1]: Low crystalline linear polyester urethane elastomer (manufactured by Sumika Bayer Urethane Co., Ltd., Desmocol (registered trademark) 406)
[UE2]: Low crystalline linear polyester urethane elastomer (manufactured by Nippon Polyurethane Industry Co., Ltd., NIPPOLAN (registered trademark) 2304)
[UE3]: Low crystalline linear polyester urethane elastomer (manufactured by Sanyo Chemical Industries, Samprene (registered trademark) IB-1700D)
[UE4]: Low crystalline linear polyester urethane elastomer (manufactured by Sanyo Chemical Industries, Samprene (registered trademark) LQ-390)
“CR”: Isocyanate-based cross-linking agent (trade name Coronate L, manufactured by Nippon Polyurethanes)

<Evaluation>
As is clear from the results shown in Table 1, the pressure-sensitive adhesive sheets of Examples 1 and 2 were excellent in each characteristic. On the other hand, in the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2, the base material was broken in the Pull test, and the reworkability and / or the tensile strength was inferior.

  Since the pressure-sensitive adhesive tape of the present invention has excellent reworkability, the parts replacement work is facilitated. Therefore, the adhesive tape of the present invention is a member constituting a portable information terminal device such as a smartphone, a mobile phone, an electronic notebook, a PHS, a tablet PC, a digital camera, a music player, a portable TV, a notebook computer, and a game machine. Useful in gluing or fixing applications. Especially, it is very useful as an adhesive sheet used for fixing battery packs and casings of devices such as smartphones and mobile phones.

Claims (7)

Has an adhesive layer on both surfaces of the base material, a peelable adhesive sheet by stretching, the substrate is low-crystalline linear polyester having a softening point conforming to JIS K 7196 is at 60 ° C. or less A pressure-sensitive adhesive sheet obtained by using a polyurethane resin as a base polymer. The pressure-sensitive adhesive sheet of the following Pull destruction no claim 1, wherein the substrate in the test.
[Pull test]
A stainless steel plate is attached to one surface of a pressure-sensitive adhesive sheet having a width of 10 mm and a length of 45 mm, and a polycarbonate plate is attached to the other surface, and a 90-degree peel test according to JIS Z 0237 is performed 24 hours later.   The pressure sensitive adhesive sheet according to claim 1 whose glass transition temperature (Tg) of a substrate is -30 ° C or more.   The pressure-sensitive adhesive sheet according to claim 1, wherein the polyurethane resin has a weight average molecular weight of 100,000 to 300,000.   The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer comprises a pressure-sensitive pressure-sensitive adhesive.   The pressure-sensitive adhesive sheet according to claim 1, wherein the thickness of the substrate is 20 to 200 µm, and the thickness of the pressure-sensitive adhesive sheet is 30 to 400 µm. The pressure-sensitive adhesive sheet according to claim 1, wherein, in the following tensile test, the tensile strength is 20 N / mm ² or more and the elongation is 500% or more.
[Tensile test]
An adhesive sheet having a width of 10 mm and a length of 100 mm is fixed to a tensile tester set at a chuck interval of 30 mm, pulled at a speed of 300 mm / min, tensile strength at break (N / mm ² ) and elongation (%) Measure.