JP2015140358A - Adhesive tape, articles and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive tape which can exhibit excellent adhesivity and excellent impact resistance, even when an area (pasting area) the adhesive tape is pasted is limited to a very narrow range.SOLUTION: There is provided an adhesive tape having an adhesive layer (A) which shows a loss tangent maximum in a temperature range of -40°C to -10°C as measured by dynamic viscoelasticity spectrum at a frequency of 1 Hz. The adhesive layer (A) contains a rubber-based block copolymer (a), and a thickness of the adhesive layer (A) is 150 μm or more in total.

Description

  The present invention relates to an adhesive tape that can be used for fixing a member constituting an electronic device such as a portable electronic terminal.

  Conventionally, the adhesive tape is suitably used for fixing members constituting various products including electronic terminals. Recently, the adhesive tape has been studied for use in fixing various members in the production scene of portable electronic terminals such as mobile phones and smartphones.

  The pressure-sensitive adhesive tape that can be used for fixing the member is, for example, a double-sided adhesive tape in which a pressure-sensitive adhesive layer is formed on both sides of a nonwoven fabric substrate, and the interlayer fracture area ratio of the double-sided adhesive tape is 10% or less, A double-sided adhesive tape is known in which the tensile strength of the double-sided adhesive tape is 20 N / 10 mm or more in both the MD direction (longitudinal direction) and the TD direction (lateral direction) (see, for example, Patent Document 1).

  However, as miniaturization of the portable electronic terminal or the like progresses, it is necessary to fix a member limited to a very narrow area where the adhesive tape can be applied. As an adhesive tape to be applied to such a narrow region, for example, an adhesive tape having a small width may be used. However, since the adhesive tape having a small width cannot exhibit the excellent adhesive force inherent in the tape, two or more members are used. May not be sufficiently fixed, and may easily peel off.

  Further, in the conventional adhesive tape, when the portable electronic terminal is dropped due to an error or the like, two or more cases and lenses constituting the portable electronic terminal are disassembled due to an impact at the time of dropping. In some cases, this could cause problems.

JP 2001-152111 A

  The problem to be solved by the present invention is that even when the area (applied part) to which the adhesive tape is applied is limited to a very narrow range, it is possible to exhibit excellent adhesive strength and excellent impact resistance. It is to provide an adhesive tape.

  The present invention is a pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer (A) in which a temperature range showing a maximum value of a loss tangent measured by a dynamic viscoelastic spectrum at a frequency of 1 Hz is in a range of −40 ° C. to −10 ° C. The pressure-sensitive adhesive layer (A) contains a rubber-based block copolymer (a), and the thickness of the pressure-sensitive adhesive layer (A) is 150 μm or more in total. It relates to an adhesive tape.

  Since the adhesive tape of the present invention is a member in which the area (applied part) to which the adhesive tape is applied is limited to a very narrow range, even if it is necessary to use a narrow adhesive tape, two or more Since it has a level of adhesive strength that can sufficiently fix the members, and is excellent in impact resistance that can withstand impacts caused by dropping or the like, it is suitable for electronic devices such as mobile electronic terminals such as mobile phones and smartphones. Can be used for manufacturing.

It is a conceptual diagram of the test piece 2 used for the measurement of surface adhesive strength, and a measurement test. It is a conceptual diagram of the test piece 5 used for the measurement of an impact resistance test.

  The pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer (A) having a temperature range in which the maximum value of loss tangent measured by a dynamic viscoelastic spectrum at a frequency of 1 Hz is in the range of −40 ° C. to −10 ° C. It is a tape, The said adhesive layer (A) contains a rubber-type block copolymer (a), and the thickness of the said adhesive layer (A) is a total of 150 micrometers or more. Features.

  As the pressure-sensitive adhesive layer (A) constituting the pressure-sensitive adhesive tape of the present invention, one having a temperature range showing a maximum value of loss tangent at a frequency of 1 Hz is -40 ° C to -10 ° C. By using a pressure-sensitive adhesive tape provided with a pressure-sensitive adhesive layer (A) having a maximum value of loss tangent in the temperature range of the above range, the region where the pressure-sensitive adhesive tape is affixed (applied part) is limited to a very narrow range. Therefore, even when it is unavoidable to use a narrow pressure-sensitive adhesive tape, it is possible to achieve both the adhesive strength at a level sufficient to fix the member and the excellent impact resistance.

  As the pressure-sensitive adhesive layer (A), it is preferable to use a layer in which the temperature range showing the maximum value of the loss tangent is in the range of −35 ° C. to −20 ° C., and in the range of −30 ° C. to −22 ° C. Even if it is necessary to use a thin adhesive tape because it is a member in which a certain thing is used, the region (applied part) to which the adhesive tape is applied is limited to a very narrow range. It is more preferable in order to further improve the adhesive strength at a level that can sufficiently fix the resin and the excellent impact resistance.

  Further, as the pressure-sensitive adhesive layer (A), it is more excellent in impact resistance to use a layer having a loss tangent maximum value in the temperature range of 0.5 to 2.5. It is preferable when providing.

  Note that the disassembly of an article obtained by attaching two members using the adhesive tape transmits vibration energy generated by dropping from one member to the other member when the article is dropped, for example. Caused by that.

  Therefore, as the adhesive tape, it is difficult to transmit the vibration energy applied to one member to the other member, that is, the use of a material having high vibration energy absorbability provides excellent impact resistance. In addition, it is preferable.

  The absorbability of the vibration energy is affected by the viscoelasticity of the adhesive tape. For example, a pressure-sensitive adhesive tape having a loss tangent (= viscosity / elasticity) maximum value X indicating the relationship between viscosity and elasticity is caused by the drop or the like in a frequency range lower than the frequency corresponding to the maximum value X. The vibration energy which can be absorbed can be absorbed suitably, As a result, the outstanding impact resistance can be expressed.

The vibration energy is exclusively correlated with temperature, and the frequency generated when an article is dropped in an environment of 25 ° C., for example, is usually about 10 ³ Hz. On the other hand, the loss tangent is usually measured by a dynamic viscoelastic spectrum at a frequency of 1 Hz. Here, the temperature when the frequency of 10 ³ Hz when the article is dropped at 25 ° C. is converted to 1 Hz is about −10 ° C. Therefore, as a pressure-sensitive adhesive tape, the temperature region showing the maximum value of loss tangent measured by a dynamic viscoelastic spectrum at a frequency of 1 Hz is a region lower than −10 ° C., specifically −40 ° C. to −10 ° C. The use of a material having a pressure-sensitive adhesive layer in the range of ° C. is suitable for exhibiting excellent impact resistance.

  The pressure-sensitive adhesive tape of the present invention is composed of, for example, a pressure-sensitive adhesive tape provided with the pressure-sensitive adhesive layer (A) on one side or both sides of a nonwoven fabric substrate or a resin film substrate, or only the pressure-sensitive adhesive layer (A). A so-called baseless adhesive tape can be mentioned.

  As said adhesive tape, what the sum total of the thickness of the adhesive layer (A) is 150 micrometers or more is used. Thereby, it is excellent in cohesion force and can provide the effect excellent in adhesive force.

  The total thickness refers to the total thickness of the pressure-sensitive adhesive layer (A), for example, if the pressure-sensitive adhesive tape has pressure-sensitive adhesive layers (A) on both surfaces of the base material. Is the thickness of the pressure-sensitive adhesive layer (A) alone constituting it.

  The total thickness of the pressure-sensitive adhesive layer (A) is preferably in the range of 150 μm to 300 μm, and in the range of 180 μm to 250 μm, the area (applied part) to which the adhesive tape is applied is extremely narrow. Even when it is necessary to use a narrow adhesive tape, it is more preferable because it can provide an adhesive force at a level that can sufficiently fix the member.

  Moreover, in the adhesive tape which has an adhesive layer (A) on both surfaces of the said base material, it is preferable that the thickness of the adhesive layer (A) of the one side is 70 micrometers or more, and is the range of 80 micrometers-120 micrometers. However, since the region where the adhesive tape is applied (applied part) is a member that is limited to a very narrow range, even if it is necessary to use a narrow adhesive tape, the level at which the member can be sufficiently fixed It is more preferable because the adhesive force can be imparted.

Further, as the pressure-sensitive adhesive layer (A), is preferably in the the storage elastic modulus G at 23 ° C. at a frequency of 1 Hz 'uses what is 1.0 × 10 ⁵ or more, 1 exceed 1.0 × 10 ⁵ The use of one having a size of 0.0 × 10 ⁷ or less is a member in which the area (applied part) to which the adhesive tape is applied is limited to a very narrow range, and a narrow adhesive tape must be used. Even so, it is more preferable because an adhesive force at a level that can sufficiently fix the member can be applied.

  The said adhesive layer (A) can be formed using the adhesive containing a rubber-type block copolymer (a).

  Examples of the rubber block copolymer (a) include so-called ABA type block copolymers (triblock copolymers), AB type block copolymers (diblock copolymers), and mixtures thereof. Can be used. As the rubber-based block copolymer (a), using a mixture of the triblock copolymer and the diblock copolymer has a maximum value of loss tangent in the temperature region, and as a result, excellent It is preferable to form a pressure-sensitive adhesive layer that achieves both good adhesion and good wettability to the adherend, and the diblock copolymer is preferably 30% of the rubber block copolymer (a) as a whole. It is more preferable to use what is contained in the range of mass% to 80 mass%, it is more preferable to use in the range of 30 mass% to 60 mass%, and it is used in the range of 40 mass% to 55 mass%. Is particularly preferred.

  As the rubber block copolymer (a), a styrene block copolymer is preferably used. The styrenic block copolymer refers to a triblock copolymer, a diblock copolymer, or a mixture thereof having a polystyrene unit (a1) and a polyolefin unit.

  The polystyrene unit (a1) increases the elastic modulus of the pressure-sensitive adhesive layer (A) and contributes to the development of excellent cohesive force.

  On the other hand, the said polyolefin unit contributes to setting the temperature range which shows the maximum value of the loss tangent of an adhesive layer (A) to a predetermined range. Thereby, the adhesive tape provided with the outstanding impact resistance can be obtained.

  Examples of the polyolefin unit include a polyisoprene unit (a2), a polybutadiene unit, a poly (butadiene-ethylene) unit, and the like, and adopting the polyisoprene unit (a2) is a loss tangent of the pressure-sensitive adhesive layer (A). The temperature range showing the maximum value of is adjusted to the predetermined range, and as a result, it is preferable to realize both excellent adhesive force and excellent impact resistance.

  The mass ratio of the polystyrene unit (a1) to the block copolymer is preferably in the range of 5% by mass to 40% by mass, for example, when the polyisoprene unit (a2) is employed as the polyolefin unit. It is more preferably in the range of 10% by mass to 30% by mass, and the use in the range of 10% by mass to 25% by mass has excellent wettability to the adherend and excellent adhesion. It is more preferable for obtaining a tape.

  On the other hand, when a polybutadiene unit or a poly (butadiene-ethylene) unit is employed as the polyolefin unit, the mass ratio is in the range of 50% by mass to 70% by mass in terms of wettability to the adherend. It is preferable for obtaining a pressure-sensitive adhesive tape having excellent adhesive strength.

  Specific examples of the rubber block copolymer (a) include styrene block copolymers such as a styrene-isoprene block copolymer, a styrene-butadiene block copolymer, and a styrene-ethylene-butylene block copolymer. Etc. can be used.

  Among these, as the rubber-based block copolymer (a), it is preferable to use a styrene-isoprene block copolymer in order to achieve both excellent adhesive strength and excellent impact resistance.

  The rubber-based block copolymer (a) preferably has a weight average molecular weight in the range of 10,000 to 800,000 in order to achieve both excellent adhesion and excellent impact resistance. It is more preferable to use those having a weight average molecular weight in the range of 50,000 to 500,000, and it is more preferable to use those having a weight average molecular weight in the range of 150,000 to 350,000.

  As the pressure-sensitive adhesive that can be used for forming the pressure-sensitive adhesive layer (A), it is preferable to use one containing a tackifying resin in addition to the rubber-based block copolymer (a).

  Examples of the tackifying resin include a rosin tackifying resin, a polymerized rosin tackifying resin, a polymerized rosin ester tackifying resin, a rosin phenol tackifying resin, a hydrogenated rosin ester tackifying resin, and a disproportionated rosin ester. System-based tackifier resins, terpene-based tackifier resins, terpene-phenol-based tackifier resins, aliphatic (petroleum resin) -based tackifier resins, and C5-based petroleum-based tackifier resins can be used.

  Among these, as the tackifying resin, it is preferable to use a C5 petroleum-based tackifying resin in order to improve wettability to the adherend surface.

  As the C5 petroleum resin, a resin obtained by polymerizing the residue obtained by extracting and separating isoprene and cyclopentadiene from a C5 fraction generally obtained by naphtha decomposition can be used.

  Further, as the tackifying resin, in addition to those described above, a tackifying resin that is liquid at room temperature can also be used. Examples of the liquid tackifying resin include low molecular weight liquid rubbers such as process oil, polyester-based tackifying resin, and polybutene.

  The liquid tackifying resin is preferably used in a range of 3% by mass to 30% by mass with respect to the total amount of the tackifying resin in order to further improve the wettability to the adherend surface.

  In addition to the above-mentioned adhesive, the pressure-sensitive adhesive may be an antioxidant, an ultraviolet absorber, an infrared absorber, a filler, a filler made of glass or plastic fibers, balloons, beads, metal powder, etc. , Pigments, thickeners and the like can be used.

  The pressure-sensitive adhesive tape of the present invention can be produced, for example, by applying the pressure-sensitive adhesive to one side or both sides of a substrate using a roll coater, a die coater or the like and drying. In addition, the pressure-sensitive adhesive tape previously forms the pressure-sensitive adhesive layer by applying the pressure-sensitive adhesive on the surface of the release liner using a roll coater and the like, and then drying the pressure-sensitive adhesive layer. It can be manufactured by a transfer method in which both surfaces are bonded.

  Moreover, the said base material-less adhesive tape can be manufactured by apply | coating the said adhesive to the surface of a release liner previously using a roll coater etc., and drying.

  As the base material constituting the adhesive tape, for example, a porous base material such as a nonwoven fabric, cloth or paper, a resin base material such as a polyester film, a polyethylene film, a polypropylene film, a plastic film such as a polyvinyl chloride film, or the like is used. Can do.

  In order to improve the anchoring property of the pressure-sensitive adhesive layer, the resin base material that has been subjected to corona treatment or anchor coat treatment can be used.

  It is preferable to use a substrate having a thickness of 4 μm to 100 μm as the substrate, and using a material having a thickness of 10 μm to 75 μm is excellent tape workability and excellent follow-up to the adherend. It is more preferable when there is an effect of imparting sex.

  The pressure-sensitive adhesive tape of the present invention may have, for example, a light-shielding layer for enhancing light-shielding properties and a reflective layer for improving reflectivity such as visible light.

  Since the pressure-sensitive adhesive tape of the present invention has high adhesive strength, it can be used, for example, for fixing a narrow member having a sticking site limited to a width of 5 mm or less.

  The narrow member is often used as a member in industrial applications such as electronic terminals such as mobile phones, automobiles, building materials, OA, and home appliance industries.

  Specific examples of the member include two or more casings and lens members that constitute an electronic terminal.

  Examples will be described in detail below.

Example 1
Styrene-isoprene block copolymer S having a weight average molecular weight of 200,000 (mixture of triblock copolymer and diblock copolymer. The proportion of the diblock copolymer to the total amount of the mixture is 52% by mass. The mass proportion of polystyrene units in the total of the styrene-isoprene block copolymer is 15 mass%, the mass proportion of polyisoprene units is 85 mass%) 100 mass parts, C5 petroleum-based tackifier resin (softening point 100 ° C, number average) Molecular weight 885) 40 parts by mass, polymerized rosin ester-based tackifier resin (softening point 125 ° C., number average molecular weight 880) 30 parts by mass, liquid tackifier resin HV-100 (manufactured by JX Nippon Mining & Energy Corporation, low molecular weight polybutene A pressure-sensitive adhesive was obtained by dissolving 5 parts by mass in toluene.

The pressure-sensitive adhesive was applied to the surface of the release liner using an applicator so that the thickness after drying was 100 μm, and dried at 85 ° C. for 5 minutes to form a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer was laminated on both sides of a 38 μm thick polyethylene terephthalate film, and then pressed and laminated at 4 kgf / cm ² to prepare a pressure-sensitive adhesive tape.

(Example 2)
An adhesive tape was prepared in the same manner as in Example 1 except that the liquid tackifying resin was not used.

(Example 3)
A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the liquid tackifier resin and the polymerized rosin ester-based tackifier resin were not used.

Example 4
A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that a nonwoven fabric substrate “Mikilon 805” having a basis weight of 14 g / m ² and a thickness of 50 μm was used instead of the 38 μm-thick polyethylene terephthalate film. .

(Example 5)
Instead of the styrene-isoprene block copolymer S used in Example 1, a styrene-isoprene block copolymer T having a weight average molecular weight of 300,000 (a mixture of a triblock copolymer and a diblock copolymer. The ratio of the diblock copolymer to the total amount of the mixture is 35% by mass, the mass ratio of polystyrene units to the total of the styrene-isoprene block copolymer is 20% by mass, and the mass ratio of polyisoprene units is 80% by mass. A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the above was used.

(Comparative Example 1)
Instead of the styrene-isoprene block copolymer S used in Example 1, a styrene-butadiene block copolymer U having a weight average molecular weight of 300,000 (a mixture of a triblock copolymer and a diblock copolymer. The ratio of the diblock copolymer to the total amount of the mixture is 20% by mass, the mass ratio of polystyrene units to the entire styrene-butadiene block copolymer is 20% by mass, and the mass ratio of polybutadiene units is 80% by mass). A pressure-sensitive adhesive tape was produced in the same manner as in Example 3 except that was used.

(Comparative Example 2)
A pressure-sensitive adhesive tape was produced in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer after drying was changed from 100 μm to 40 μm.

(Comparative Example 3)
(Preparation of adhesive)
In a reaction vessel equipped with a stirrer, cold flow cooler, thermometer, dropping funnel and nitrogen gas inlet, 44.9 parts by mass of butyl acrylate, 50 parts by mass of 2-ethylhexyl acrylate, 2 parts by mass of acrylic acid, 3 parts by mass of vinyl acetate By dissolving 0.1 part by mass of 4-hydroxybutyl acrylate and 0.1 part by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator in 100 parts by mass of ethyl acetate and polymerizing at 70 ° C. for 10 hours. An acrylic copolymer solution having a weight average molecular weight of 800,000 was obtained.

  Next, by adding 30 parts by mass of a polymerized rosin ester tackifying resin (softening point 125 ° C., number average molecular weight 880) to 100 parts by mass of the acrylic copolymer, adding ethyl acetate and mixing them, An adhesive having a nonvolatile content of 45% by mass was obtained.

“Coronate L-45” manufactured by Nippon Polyurethane Industry Co., Ltd. with respect to 100 parts by mass of the adhesive.
1.1 parts by weight of (isocyanate-based crosslinking agent, solid content 45% by weight) was added and stirred for 15 minutes, and then applied onto the separator using an applicator so that the thickness after drying was 100 μm, and 85 Dry at 5 ° C. for 5 minutes.

Next, two pressure-sensitive adhesive layers coated on the separator were prepared, and these were bonded to both sides of a 38 μm-thick PET film, and then laminated with a pressure of 4 kgf / cm ² , and a pressure-sensitive adhesive tape. Was made.

(1) Dynamic viscoelasticity measurement of pressure-sensitive adhesive layer The surface of the release liner so that the pressure-sensitive adhesive used in the production of the pressure-sensitive adhesive tapes of Examples and Comparative Examples is 100 μm after drying using an applicator. And dried at 85 ° C. for 5 minutes to form an adhesive layer having a thickness of 100 μm.

  Next, a plurality of the pressure-sensitive adhesive layers were prepared, and the test pieces made of a pressure-sensitive adhesive layer having a thickness of 2 mm were prepared by superimposing them.

  A parallel plate having a diameter of 7.9 mm was attached to a viscoelasticity tester (ARES 2kSTD) manufactured by TA Instruments Japan. The test piece is sandwiched between the parallel plates with a compression load of 40 to 60 g, and the temperature showing the maximum value of the loss tangent under the conditions of a frequency of 1 Hz, a temperature range of −60 to 150 ° C., and a heating rate of 2 ° C./min [ ° C], the maximum value at that temperature, and the storage elastic modulus [Pa] at 23 ° C.

Adhesive strength evaluation method (surface adhesive strength)
Under the environment of 23 ° C., the pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were cut into a frame shape having a side (outer shape) length of 14 mm and a width of 2 mm.

  The cut adhesive tape 2 was attached to an acrylic plate 1 which is a rectangular parallelepiped having a length of 15 mm, a width of 15 mm, and a thickness of 2 mm. At that time, a test piece 1 was prepared by attaching one side of the cut adhesive tape 2 so as to correspond to one side 15 mm of the acrylic plate 1.

Next, the 20 mm long, 50 mm wide and 1 mm thick SUS plate 3 having a hole with a diameter of 10 mm in the center is pasted to the adhesive tape side surface of the test piece 1 so that their centers coincide. Then, after pressurizing at 80 N / cm ² for 10 seconds using a press machine, the pressed state was released, and the specimen 2 was produced by allowing it to stand at 23 ° C. for 1 hour.

Next, a tensile tester (A & D Tensilon RTA-100, compression mode) equipped with a stainless steel probe 4 having a diameter of 8 mm was prepared. When the probe 4 applied a force to the test piece 1 constituting the test piece 2 through the hole of the SUS plate 3 constituting the test piece 2, the test piece 1 was peeled off from the SUS plate 3. The strength (N / cm ² ) was measured. The speed at which the probe 4 pushes the test piece 1 was set to 10 mm / min.

Adhesive strength evaluation method (180 degree peeling adhesive strength)
180 degree peeling adhesion was measured according to JIS Z 0237.

  The release liner on one side of the adhesive tape was peeled off, and the adhesive layer was lined with a polyethylene terephthalate film (PET film) having a thickness of 25 μm.

  The backed adhesive tape was cut into a width of 20 mm, the release liner on the other side was peeled off, and the adhesive layer was bonded to a SUS plate to make a test piece 3.

  The test piece 3 was allowed to stand at 23 ° C. and 50% RH for 30 minutes, and in that environment, a Tensilon tensile tester [manufactured by A & D Co., Ltd., model: RTM-100] was used. The adhesive force when the double-sided pressure-sensitive adhesive tape to be formed was peeled off from the SUS plate in the 180 ° direction at a speed of 300 mm / min was measured.

Evaluation method of impact resistance In an environment of 23 ° C., two adhesive tapes obtained by cutting the adhesive tapes obtained in Examples and Comparative Examples into rectangles having a length of 20 mm and a width of 2 mm were prepared.

  Next, the two cut adhesive tapes 6 were affixed in parallel with an interval of 44 mm on the surface of the acrylic plate 5 which is a rectangular parallelepiped having a length of 20 mm, a width of 50 mm and a thickness of 2 mm.

Acrylic plate 7 which is a rectangular parallelepiped having a length of 50 mm, a width of 50 mm and a thickness of 2 mm is pasted on the pasting surface, and after pressing for 10 seconds at 80 N / cm ² using a press machine, the pressurized state is released. The test piece 4 was produced by leaving still at 23 degreeC environment for 1 hour.

  Next, a test piece 5 was prepared by fixing a 300 g weight 8 using a tape 9 on the surface of the acrylic plate 5 constituting the test piece 4.

The test piece 5 was dropped from a height of 10 cm using a DuPont impact tester (manufactured by Tester Sangyo Co., Ltd.). After dropping the test piece 5 times from the height of 10 cm, if the peeling between the acrylic plate 5 and the acrylic plate 7 constituting the test piece 5 could not be confirmed, the test piece 5 was dropped from a height of 10 cm higher, Again, the presence or absence of peeling between the acrylic plate 5 and the acrylic plate 7 was confirmed. This test was repeated until the drop height reached 80 cm.
A: Even if the dropped height was 80 cm, peeling could not be confirmed.
○: Even if the dropped height was 70 cm, peeling could not be confirmed.
X: Separation was confirmed when the dropped height was less than 70 cm.

1 Acrylic plate 2 Cut adhesive tape 3 SUS plate 4 Probe 5 Acrylic plate (x)
6 Cut adhesive tape 7 Acrylic plate (y)
8 Weight 9 Adhesive tape for fixing weight

Claims (11)

A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer (A) in which a temperature range showing a maximum value of a loss tangent measured by a dynamic viscoelastic spectrum at a frequency of 1 Hz is in a range of −40 ° C. to −10 ° C. The pressure-sensitive adhesive tape, wherein the agent layer (A) contains the rubber-based block copolymer (a), and the pressure-sensitive adhesive layer (A) has a total thickness of 150 μm or more. The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive layer (A) has a storage elastic modulus G ′ measured by a dynamic viscoelastic spectrum at 1 Hz and 23 ° C. of 1.0 × 10 ⁵ Pa or more. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the rubber-based block copolymer (a) is a block copolymer having a polystyrene unit (a1) and a polyisoprene unit (a2). The pressure-sensitive adhesive tape according to claim 1, wherein the pressure-sensitive adhesive layer (A) further contains a tackifier resin. The pressure-sensitive adhesive layer (A) is provided on both sides of the base material, and the thickness of the pressure-sensitive adhesive layer (A) provided on at least one side of the base material is 70 μm or more. The adhesive tape of any one of Claims. The pressure-sensitive adhesive tape according to any one of claims 1 to 5, wherein the width is 5 mm or less. The pressure-sensitive adhesive tape according to claim 6, which is used for fixing two or more casings constituting an electronic device. At least one of the two or more cases has a sticking part with a width of 5 mm or less, and the sticking part is joined to the other case via the adhesive tape according to claim 6 or 7. Article characterized by having a structure. An electronic apparatus, wherein two or more casings are fixed by the adhesive tape according to claim 1. The electronic device according to claim 9, wherein at least one of the two or more cases is a lens member. The electronic device according to claim 9, wherein a range to which the adhesive tape according to any one of claims 1 to 7 is attached is a narrow region having a width of 5 mm or less.

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