WO2020175368A1

WO2020175368A1 - Dual-sided pressure-sensitive adhesive tape, electronic apparatus component, and electronic apparatus

Info

Publication number: WO2020175368A1
Application number: PCT/JP2020/007043
Authority: WO
Inventors: 明史堀尾; 繁季松木; 泰志石堂; 寛幸片岡
Original assignee: 積水化学工業株式会社
Priority date: 2019-02-25
Filing date: 2020-02-21
Publication date: 2020-09-03
Also published as: KR20210129046A; CN113490728A; JPWO2020175368A1; JP7044878B2; CN113490728B

Abstract

The purpose of the present invention is to provide: a dual-sided pressure-sensitive adhesive tape that can be suitably used to secure electronic apparatus components and to secure vehicle components and that has high flexibility, shock resistance, and repulsion resistance; and an electronic apparatus component and an electronic apparatus that use the dual-sided pressure-sensitive adhesive tape. The present invention is a dual-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a foam substrate, wherein: the average long diameter of air bubbles in the foam substrate is at most 150 µm; the 25% compression strength of the dual-sided pressure-sensitive adhesive tape is at most 500 kPa; the ratio of the thickness of the foam substrate to the thickness of the dual-sided pressure-sensitive adhesive tape is at least 0.5; and the shift length of the dual-sided pressure-sensitive adhesive tape according to a cohesion test is 35–110 µm.

Description

\¥0 2020/175368 1 卩 (: 17 2020 /007043 Clarification

Title of invention: Double-sided adhesive tape, electronic device parts and electronic device Technical Field

The present invention relates to a double-sided pressure-sensitive adhesive tape, an electronic device component using the double-sided pressure-sensitive adhesive tape, and an electronic device.

Background technology

[0002] In a mobile electronic device (for example, a mobile phone, a mobile information terminal, etc.) equipped with an image display device or an input device, a double-sided adhesive tape is used for assembly. Specifically, for example, a double-sided adhesive tape is used to attach a cover panel for protecting the surface of a portable electronic device to a touch panel module or a display panel module, or to attach a touch panel module and a display panel module. Is used. Such a double-sided adhesive tape is used, for example, by punching it into a frame-like shape and arranging it around the display screen (for example, Patent Documents 1 and 2). Double-sided adhesive tape is also used to fix vehicle parts (eg, vehicle-mounted panels) to the vehicle body.

[0003] The double-sided pressure-sensitive adhesive tape used for fixing parts of portable electronic devices has not only high adhesive strength, but also does not cause cracking or delamination of the double-sided pressure-sensitive adhesive tape even when it is dropped or otherwise subjected to a strong impact. High impact resistance is required. As a double-sided adhesive tape having excellent impact resistance, for example, in Patent Documents 1 and 2, an acryl-based pressure-sensitive adhesive layer is laminated and integrated on at least one side of a base material layer, and the base material layer has a specific crosslinking degree. Further, a crosslinked polyolefin resin foam sheet having an asphalt ratio of bubbles is disclosed.

Prior art documents

Patent literature

Patent Document 1: Japanese Patent Laid-Open No. 20 09 _ 2 4 2 5 4 1

Patent Document 2: Japanese Unexamined Patent Publication No. 2 0 9 -2 5 8 2 7 4 \¥0 2020/175368 2 ((17 2020/007043 Summary of the invention

Problems to be Solved by the Invention

[0005] In recent years, portable electronic devices have adopted a design that uses many curved surfaces that are excellent in design. In order to attach the double-sided adhesive tape to such curved parts of portable electronic devices, it is necessary to have high flexibility to follow curved surfaces. In addition, the double-sided adhesive tape adhered to a curved surface is subject to stress due to uneven pressure bonding and stress that tends to return the tape to its original shape, so repulsion resistance that does not separate even with this stress is required. It Further, as described above, the double-sided adhesive tape used to fix parts of portable electronic devices requires high impact resistance, but in order to improve impact resistance, it is necessary to make the double-sided adhesive tape hard. There is a trade-off between flexibility and impact resistance. Therefore, it is difficult to obtain a double-sided pressure-sensitive adhesive tape having high impact resistance, flexibility and repulsion resistance.

In view of the above situation, the present invention is a double-sided pressure-sensitive adhesive tape having high flexibility, impact resistance and repulsion resistance, which can be suitably used for fixing electronic device parts and fixing vehicle parts. The purpose is to provide electronic equipment parts and equipment using double-sided adhesive tape.

Means for solving the problem

[0007] The present invention is a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a foam substrate, wherein the foam substrate has an average major axis of bubbles of 150 000 or less. The tape has a 25% compressive strength of 5 OO k P ₃ or less, the double-sided adhesive tape has a foam substrate thickness/double-sided adhesive tape thickness of 0.5 or more, and the double-sided adhesive tape is It is a double-sided pressure-sensitive adhesive tape with a deviation amount of 35 or more and 1 110 or less according to the cohesive strength test.

The present invention will be described in detail below.

The double-sided pressure-sensitive adhesive tape of the present invention is a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a foam base material.

By using a foam base material as the base material of the double-sided pressure-sensitive adhesive tape, it has high flexibility to follow irregularities and curved surfaces of the adherend, and it is difficult for cracks and peeling to occur due to impact such as dropping. \¥0 2020/175368 3 卩 (: 171? 2020 /007043

It can exhibit high impact resistance.

[0009] The double-sided pressure-sensitive adhesive tape of the present invention has a 25% compression strength of not more than 5001 <3.

By adjusting the 25% compressive strength of the double-sided pressure-sensitive adhesive tape within the above range, the flexibility can be improved. From the viewpoint of further improving flexibility, the above 25% compressive strength

The following is preferable, it is more preferable that it is 4501<3 or less, it is further preferable that it is 4001<3 or less, and it is still more preferable that it is 3501<3 or less. , Particularly preferably 0,011<3 or less, particularly preferably 2,500<1 or less,

Is more preferable, 1 0 0 1 <3 or less is very preferable, and 1 0 0 1 < ₃ or less is most preferable. The lower limit of the 25% compressive strength is not particularly limited, but is preferably from the viewpoint of balance with impact resistance.

More preferably, 7 0 1 <3. The 25% compressive strength can be controlled by the type of the foam substrate, the expansion ratio, the average major axis of cells, and the type of the acrylic pressure-sensitive adhesive constituting the acrylic pressure-sensitive adhesive layer.

The 25% compressive strength can be measured in accordance with "" 3 <6 7 6 7. Specifically, the double-sided pressure-sensitive adhesive tape cut to 20 20 is stacked to form a laminate with a thickness of 100 1 and left at room temperature for 1 hour, and then, at room temperature, in the thickness direction of this laminate. It is possible to calculate the compressive strength of 25% from the obtained 3-3 force by compressing it to 50% of the original thickness at the rate of 10 |^○ 1 / |11 丨.

The double-sided pressure-sensitive adhesive tape of the present invention has a foam substrate thickness/double-sided pressure-sensitive adhesive tape thickness of 0.5 or more.

When the ratio of the thickness of the foam base material to the thickness of the double-sided pressure-sensitive adhesive tape is within the above range, flexibility and impact resistance can be increased. Further, by satisfying the above 25% compressive strength at the same time, the repulsion resistance can be further enhanced. From the viewpoint of further improving flexibility, impact resistance, and repulsion resistance, the foam base material thickness/double-sided adhesive tape thickness is preferably 0.65 or more, and 0.75 or more. Is more preferable, and 0.85 or more is further preferable. The upper limit of the foam substrate thickness/double-sided adhesive tape thickness is not particularly limited, but from the viewpoint of handleability \¥0 2020/175368 4 卩 (: 171? 2020 /007043

It is preferably 0.99 or less, more preferably 0.95 or less, and further preferably 0.9 or less.

[001 1] The double-sided pressure-sensitive adhesive tape of the present invention has a deviation amount of 35 or more by the cohesive force test 1 10

It is 111 or less.

When the amount of deviation in the cohesive strength test is 35 or more, the double-sided pressure-sensitive adhesive tape has an appropriate hardness, and high adhesive strength and flexibility can be exhibited. In addition, when the amount of deviation in the cohesive strength test is 110 or less, the double-sided adhesive tape does not become too soft and high repulsion resistance can be exhibited. From the viewpoint of further improving flexibility and repulsion resistance, the amount of deviation in the above cohesive force test is preferably 45 or more, more preferably 50 or more, and preferably 100 or less, It is more preferably 90 or less, and further preferably 80 or less. The amount of deviation due to the cohesive strength test can be controlled by the kind of the acrylic adhesive forming the acrylic adhesive layer, the thickness of the acrylic adhesive layer, and the like.

[0012] The cohesive strength test can be measured by the following method.

Figure 1 shows a schematic diagram showing the cohesive strength test of a double-sided adhesive tape. First, a double-sided pressure-sensitive adhesive tape in which an acrylic adhesive layer is formed on both sides of a foam substrate is prepared. Then, as shown in Fig. 1, using the double-sided adhesive tape 1 cut to 2 0 01 01 X 4 0 01 01,

Stainless plate (3 II 3 # 3 0 4) 2 1 and width

Attach the Mingo Film 2 of 2. At 23 °C, fix one end of one stainless steel plate 21 and pull one end of the Mending film 2 2 horizontally for 3 minutes with the weight 23 of 2 09. At this time, measure the displacement of the double-sided adhesive tape 1 that is displaced in the pulling direction. The longitudinal direction of the double-sided adhesive tape is the pulling direction in Fig. 1.

[0013] In the foam substrate, the average major axis of cells is 150 or less.

By making the average major axis of the foam base material smaller than that of the double-sided pressure-sensitive adhesive tape having a conventional foam base material, the area formed by the foam even with the same expansion ratio. You can increase the number of pictures (cells). As the number of cells increases, it is possible to disperse the impact of dropping and the stress when attached to a curved surface, so the strength of the double-sided adhesive tape can be improved, and the impact resistance and repulsion resistance can be improved. .. On the other hand, even if the average major axis of air bubbles is reduced, the flexibility is the same as that of the larger average major axis of bubbles, so long as the expansion ratio is the same, while improving impact resistance and repulsion resistance. Can also maintain flexibility.

From the viewpoint of further improving the impact resistance and the repulsion resistance, the average major diameter of the cells of the foam base material is preferably 140 Mm or less, more preferably 135 Mm or less, and 125 Mm or less. More preferably, 1 20

It is even more preferably below, and particularly preferably 110 Mm or below. The lower limit of the average major axis of the foam base material is not particularly limited as long as it is larger than 0, but it is preferably 40 Mm from the viewpoint of balance between impact resistance, repulsion resistance and flexibility. The average major axis of bubbles in the foam substrate can be controlled by controlling the elongation due to the difference in the winding speed during foaming.

[0014] The average major axis and the average minor axis of the cells of the foam substrate can be measured by the following method.

First, cut the foam base material into a square of 5 Omm, soak it in liquid nitrogen for 1 minute, and then cut it with a razor blade in a plane parallel to the MD direction and perpendicular to the plane between the MD and TD directions. To do. Then, using a digital microscope (for example, "VHX-900" manufactured by KEYENCE CORPORATION), a magnified photograph of the cut surface was taken at a magnification of 200, and the range of 2 mm in the MD direction (thickness X 2 mm The cell diameter in the MD direction is measured for all cells existing in the range (1). This operation is repeated 5 times, and the average bubble diameters in the MD direction are calculated by averaging all the obtained bubble diameters. Then, the average cell diameter in the T D direction is obtained by the same method except that the foam base material is cut along a plane parallel to the T D direction and perpendicular to the plane formed by the M D direction and the T D direction. Of the obtained average bubble diameters in the MD and T D directions, the larger one is the average length of the bubbles, and the shorter one is the average length of the bubbles.

Note that MD (Machine Direction) is a foam base material — This is the extrusion direction when extrusion processing is done in the shape of a turret, and TD (tranverse direction) is the direction perpendicular to MD.

[0015] The foam substrate has a cell aspect ratio (minor axis/major axis) of preferably 0.65 or more, more preferably 0.7 or more, still more preferably 0.75 or more, still more preferably 0.8. Above, particularly preferably 0.85 or more, and particularly preferably 0.9 or more. The foam aspect ratio of the foam base material within the above range reduces the difference in the number of compartments (cells) formed by bubbles in the MD and TD directions, resulting in impact resistance and repulsion resistance in the tape direction. As a result, the impact resistance and repulsion resistance of the entire tape can be improved. The upper limit of the bubble aspect ratio is not particularly limited, but is usually 1 or less, for example, 0.97 or less.

The bubble aspect ratio can be calculated by dividing the average minor axis of the bubbles by the average major axis.

[0016] The foam substrate preferably has a foaming ratio of 2 cm ³ /g or more and 5 cm ³ /g or less.

When the expansion ratio of the foam base material is within the above range, the obtained double-sided pressure-sensitive adhesive tape can have higher flexibility and can easily satisfy the 25% compressive strength. From the viewpoint of balancing flexibility with impact resistance and repulsion resistance, the foaming ratio of the foam base material is more preferably 2.5 m ³ /g or more, 3 cm ³ /g Or more, more preferably 3.5 cm ³ /g or more, even more preferably, 4.7 cm ³ /g or less, more preferably 4.5 cm ³ /g or less. More preferably.

The expansion ratio of the foam can be adjusted depending on the material of the foam substrate, the thickness, the number of parts of the foaming agent, and the like.

The expansion ratio of the foam base material can be calculated from the reciprocal of the density of the foam. For example, it can be measured according to JISK 7222.

[0017] The foam substrate is not particularly limited, and examples thereof include a polyolefin foam and a urethane foam. Above all, because it is easy to achieve the above physical properties \¥0 2020/175368 7 卩 (: 171? 2020 /007043

It is preferably a polyolefin foam. Examples of the above-mentioned polyolefin foams include polyethylene foams, polypropylene foams, ethylene-propylene foams, and the like. Of these, polyethylene foam is preferable.

[0018] The polyolefin resin constituting the above-mentioned polyolefin foam is not particularly limited, but a polyolefin resin obtained by using a metallocene compound containing a tetravalent transition metal as a polymerization catalyst is preferable. Among them, the polyethylene resin obtained by using the metallocene compound is more preferable. Examples of the metallocene compound include Kaminsky catalysts.

[0019] As the polyethylene resin obtained by using the above metallocene compound, for example, by using the above metallocene compound, ethylene is obtained by copolymerizing with other olefins that are blended as necessary. Examples include polyethylene resin. Examples of the above-mentioned other <<-olefins include propene, 1-butene, 1-pentene, 1-hexene and the like.

[0020] The polyethylene resin obtained by using the metallocene compound may be used in combination with another olefin resin. Examples of the other olefin resin include polyethylene, polypropylene, ethylene-propylene copolymer, and the like.

[0021] The foam substrate is preferably crosslinked. Impact resistance can be enhanced by crosslinking the foam substrate.

The method for cross-linking the foam substrate is not particularly limited, and, for example, an electron beam, <<beam,

And ionizing radiation such as X-rays, and a method of decomposing an organic peroxide previously blended in the foam base material by heating.

The method for producing the foam base material is not particularly limited. For example, a foamable resin composition containing a base resin and a foaming agent is prepared, and the foamable resin composition is formed into a sheet using an extruder. A method is preferred in which a foaming agent is foamed at the time of extrusion processing into a sheet shape, and the obtained foam substrate is crosslinked if necessary. \¥0 2020/175368 8 卩 (: 171? 2020 /007043

[0023] The thickness of the foam substrate is not particularly limited, but a preferred lower limit is 30, a more preferred lower limit is 50, a still more preferred lower limit is 7001, and a still more preferred lower limit is 100, especially A preferred lower limit is 150, and a particularly preferred lower limit is 200. When the thickness of the foam substrate is at least the above lower limit, the impact resistance of the obtained double-sided pressure-sensitive adhesive tape can be further improved. The thickness of the foam substrate is not particularly limited, but a preferred upper limit is 700, a more preferred upper limit is 600, a still more preferred upper limit is 500, and a still more preferred upper limit is 400, and particularly preferred. The upper limit is 300, and the particularly preferable upper limit is 2700. When the thickness of the foam base material is not more than the upper limit, the flexibility of the obtained double-sided pressure-sensitive adhesive tape can be further improved. In the present invention, the thickness of the foam base material and the pressure-sensitive adhesive layer can be measured by the following method.

First, cut the tape in a 50-square direction, soak it in liquid nitrogen for 1 minute, and then use a razor blade to make it parallel to the IV! 0 direction and perpendicular to the plane defined by the IV! 0 direction and the mouth direction. Cut at a sharp surface. Then, using a digital microscope (for example, "▽1 ^~ 1_900_" manufactured by KEYENCE CORPORATION), an enlarged photograph of the cut surface was taken at a magnification of 200x, and the tape thickness was measured. Measure the total length in the direction. This operation is performed by randomly measuring 5 points in the range of 2 in the IV! 0 direction and averaging all the total lengths.

— Calculate the thickness of the tape. Then, the total length of the foam base material in the thickness direction is measured by the same method, and the total length is averaged to calculate the thickness of the foam base material. The thickness of the pressure-sensitive adhesive layer is calculated by taking the difference of the foam base material thickness from the tape thickness.

[0024] Acrylic pressure-sensitive adhesive constituting the acrylic adhesive layer, it preferably has a storage elastic-resistance ratio in 2 3 ^° 〇 is 4 X 1 〇 ⁵ 3 below.

When the storage elastic modulus of the acrylic pressure-sensitive adhesive at 23° is in the above range, the acrylic pressure-sensitive adhesive becomes moderately soft, and thus the pressure-sensitive adhesive force and flexibility of the obtained double-sided pressure-sensitive adhesive tape can be further improved. From the viewpoint of further improving the adhesive strength and flexibility of the obtained double-sided pressure-sensitive adhesive tape, storage of the above acrylic pressure-sensitive adhesive at 23 ^° \¥02020/175368 9 卩 (: 171? 2020 /007043

Built modulus is more preferably 3. at 5 X 1 0 ^ 3 or less, 3 more preferably X 1 is 0 ⁵ 3 or less, preferably more than that 2. is 8 1 0 ⁵ 3 below, 2. it is particularly preferably 7 X 1 〇 ⁵ 3 below. The lower limit of the storage elastic modulus at 23° of the acrylic adhesive is not particularly limited, but it is preferably 2×10 ⁵ ₃ from the viewpoint of balance between impact resistance and repulsion resistance and handleability. The storage elastic modulus of the acrylic adhesive at 23 ^° can be adjusted by the glass transition temperature of the raw material monomer of the acrylic adhesive. The storage elastic modulus of the above acrylic adhesive at 23° 〇 was measured using a viscoelasticity spectrometer (for example, 081200, manufactured by IT Measurement and Control Co., Ltd.) at a constant temperature rising tension mode of 10 ^° 〇. The storage elastic modulus at 23 ^° can be obtained when the dynamic viscoelastic spectrum of 1 ^° 40°° to 140°° is measured under the condition of /01 ^to 1 ^° /min.

The above-mentioned acrylic pressure-sensitive adhesive preferably has a storage elastic modulus at 140° ◯ of 3×10 ⁴ 3 or more.

Storage modulus at high temperature correlates with long-term fluidity. When the acrylic adhesive has a storage elastic modulus ^at 140 ^° 〇 in the above range, it is difficult for the adhesive to flow even after a long period of time, that is, it is difficult to deform even when stressed for a long period of time. The repulsion resistance of the adhesive tape can be further enhanced. From the viewpoint of further improving the repulsion resistance of the obtained double-sided pressure-sensitive adhesive tape, the storage elastic modulus at 140 ^° 〇 of the above-mentioned acrylic pressure-sensitive adhesive is more preferably 3.1 × 10^3 or more, and 3.2 and still more preferably X is 1 〇 ⁴ 3 or more. The upper limit of the storage elastic modulus ^at 140 ^° 〇 of the above-mentioned acrylic adhesive is not particularly limited, but is, for example, 1 XI 〇 ⁵ 3. As a method of controlling the storage elastic modulus of the above-mentioned acrylic adhesive ^at 140 ^° in the above range, there is a method of narrowing the molecular weight distribution (weight average molecular weight IV! number average molecular weight !\/^). Further, a method of adjusting the softening point, content, etc. of the tackifying resin, a method of adjusting the gel fraction of the acrylic pressure-sensitive adhesive layer, and the like are also included.

The storage elastic modulus of the above acrylic adhesive ^at 140 ^° is \¥0 2020/175368 10 卩 (: 171? 2020 /007043

It can be obtained as the storage elastic modulus ^at 140 ^° when the dynamic viscoelastic spectrum is measured by the same method as the storage elastic modulus at 23° of the adhesive.

[0026] The acrylic pressure-sensitive adhesive is not particularly limited, but it is an acrylic copolymer obtained by copolymerizing a monomer mixture containing butyl acrylate and 2-ethylhexyl acrylate, since it is easy to satisfy the above parameters. Is preferred.

The preferable lower limit of the content of butyl acrylate in the total monomer mixture is 40% by weight, and the preferable upper limit thereof is 80% by weight. When the content of butyl acrylate is within this range, both high adhesive strength and cohesive strength can be achieved. A preferable lower limit of the content of 2-ethylhexyl acrylate in the total monomer mixture is 10% by weight, and a preferable upper limit thereof is 40% by weight. When the content of 2-ethylhexyl acrylate is within this range, both high adhesive strength and cohesive strength can be achieved.

[0027] The above-mentioned monomer mixture may optionally contain other copolymerizable polymerizable monomer other than butyl acrylate and 2-ethylhexyl acrylate.

Examples of the other copolymerizable monomer that can be copolymerized include, for example, (meth)methyl acrylate, (meth)ethyl acrylate, (meth)acrylic acid 11-propyl, and (meth)isopropyl acrylate. (Meth)acrylic acid alkyl ester having 1 to 3 (meth)acrylic acid alkyl ester, tridecyl methacrylate, (meth)acrylic acid stearyl, etc., having a carbon number of 13 to 18 carbon atoms in the alkyl group, (meth)acrylic acid Hydroxyalkyl acid, glycerin dimethacrylate, (meth)glycidyl acrylate, 2-methacryloyloxy ethyl isocyanate, (meth)acrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, fumaric acid and other functional monomers. To be

[0028] In order to copolymerize the monomer mixture to obtain the acrylic copolymer, the monomer mixture may be subjected to a radical reaction in the presence of a polymerization initiator. The polymerization initiator is not particularly limited, and examples thereof include organic peroxides and azo compounds. To be Examples of the above-mentioned organic peroxide include 1, 1 _ bis (1 _ hexylperoxy) _ 3, 3, 5-trimethylcyclohexane, t _ hexylperoxypivalate, t _ butylperoxypivalate, 2, 5-dimethyl-2 , 5-bis(2-ethylhexanoylperoxy) hexane, t _ hexyl peroxy _ 2 -ethyl hexanoate, t -butyl peroxy _ 2 -ethyl hexanoate, t _ butyl peroxyisobutyrate, t _Putylperoxy_3,5,5-trimethylhexanoate, t_Putylperoxylaurate and the like. Examples of the azo compound include azobisisobutyronitrile and azobiscyclohexanecarbonitrile. These polymerization initiators may be used alone or in combination of two or more kinds.

As a method of radically reacting the above-mentioned monomer mixture, that is, as a polymerization method, a conventionally known method is used, for example, solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, living Radical polymerization etc. are mentioned. Of these, low-temperature polymerization or living radical polymerization is preferable because the molecular weight distribution can be narrowed and the storage elastic modulus at high temperature can be increased.

[0030] With respect to the weight average molecular weight (Mw) of the acrylic copolymer, a preferred lower limit is 400,000, and a preferred upper limit is 1200,000. When the weight average molecular weight is in the above range, the cohesive force of the acrylic pressure-sensitive adhesive layer is increased, and the pressure-sensitive adhesive force of the double-sided pressure-sensitive adhesive tape is further improved. The more preferable lower limit of the weight average molecular weight is 500,000, and the more preferable upper limit thereof is 110,000.

In order to adjust the weight average molecular weight within the above range, the polymerization conditions such as the polymerization initiator and the polymerization temperature may be adjusted.

The weight average molecular weight (Mw) is the weight average molecular weight in terms of standard polystyrene by GPC (Gel Permeat i o n C h r om a t o g r a p h y: gel permeation chromatography).

[0031] The acrylic pressure-sensitive adhesive layer may contain a tackifying resin.

Examples of the tackifying resin include rosin ester resin, hydrogenated rosin resin, terpene resin, terpene phenol resin, coumarone indene resin. \¥0 2020/175368 12 卩 (: 171? 2020 /007043

Alicyclic saturated hydrocarbon resin, 05 petroleum resin, 09 petroleum resin, 05-9 copolymer petroleum resin and the like. These tackifying resins may be used alone or in combination of two or more.

The content of the tackifying resin is not particularly limited, but a preferable lower limit is 100 parts by weight and a preferable upper limit is 60 parts by weight with respect to 100 parts by weight of the acrylic copolymer. When the content of the tackifying resin is within this range, a high adhesive strength can be exerted.

[0033] In the acrylic pressure-sensitive adhesive layer, a cross-linking structure is formed between the main chains of the resin (the acrylic copolymer and/or the tackifying resin) constituting the acrylic pressure-sensitive adhesive layer by adding a crosslinking agent. Is preferably provided. By forming a crosslinked structure in the acrylic pressure-sensitive adhesive layer, it is possible to easily control the storage elastic modulus within the above range.

The crosslinking agent is not particularly limited, and examples thereof include an isocyanate crosslinking agent, an aziridin crosslinking agent, an epoxy crosslinking agent, and a metal chelate crosslinking agent. Of these, isocyanate crosslinking agents are preferred.

With respect to the amount of the crosslinking agent added, a preferred lower limit is 0.01 part by weight, a preferred upper limit is 10 parts by weight, and a more preferred lower limit is 0.1 part by weight, relative to 100 parts by weight of the acrylic copolymer. A more preferable upper limit is 3 parts by weight.

[0034] The acrylic pressure-sensitive adhesive layer preferably has a gel fraction of 20% or more.

When the gel fraction of the acrylic pressure-sensitive adhesive layer is within the above range, it is possible to easily satisfy the amount of deviation in the cohesive strength test. From the viewpoint of making it easier to satisfy the shift amount, the gel fraction of the acrylic pressure-sensitive adhesive layer is more preferably 25% or more, further preferably 30% or more, still more preferably 35% or more, particularly preferably It is 40% or more. The upper limit of the gel fraction of the acrylic pressure-sensitive adhesive layer is not particularly limited, but from the viewpoint of achieving both adhesive strength and flexibility of the obtained double-sided pressure-sensitive adhesive tape, it is preferably 80%, more preferably 75%. , More preferably 70%, even more preferably 65%.

[0035] The thickness of the acrylic pressure-sensitive adhesive layer is not particularly limited. \¥0 2020/175368 13 卩 (: 171? 2020 /007043

The preferred lower limit of the layer thickness is 1001, and the preferred upper limit is 100! When the thickness of the acrylic pressure-sensitive adhesive layer is within the above range, it is possible to easily adjust the above deviation amount within the above range, and both sides having higher flexibility, impact resistance and repulsion resistance are provided. It can be an adhesive tape. The more preferable lower limit of the thickness of the acrylic pressure-sensitive adhesive layer is 15, the more preferable lower limit is 201, the still more preferable lower limit is 25, the more preferable upper limit is 80, and the still more preferable upper limit is 7001. A more preferable upper limit is 600!

The double-sided pressure-sensitive adhesive tape of the present invention has a total thickness of the double-sided pressure-sensitive adhesive tape of preferably 50 or more, more preferably 70 or more, still more preferably 100 or more, still more preferably 150 or more, It is preferably 900 or less, more preferably 700 or less, even more preferably 500 or less, and even more preferably 400 or less. When the total thickness of the double-sided pressure-sensitive adhesive tape is within the above range, it is possible to obtain a pressure-sensitive adhesive tape that is more easy to handle and has high flexibility, impact resistance, and repulsion resistance.

[0037] As a method for producing the double-sided pressure-sensitive adhesive tape of the present invention, for example, the following method can be mentioned.

First, a solvent is added to the acrylic pressure-sensitive adhesive, optionally a tackifying resin, a crosslinking agent, etc. to prepare a solution of the acrylic pressure-sensitive adhesive, and the solution of the acrylic pressure-sensitive adhesive is applied to the surface of the foam substrate, The solvent in the solution is completely dried and removed to form the acrylic adhesive layer 8. Next, a release film is laminated on the formed acrylic pressure-sensitive adhesive layer 8 so that the release-treated surface faces the acrylic pressure-sensitive adhesive layer. Then, a release film different from the above-mentioned release film is laminated. Prepare and apply a solution of acrylic pressure sensitive adhesive to the release treated surface of this release film and completely dry and remove the solvent in the solution to form an acrylic pressure sensitive adhesive layer on the surface of the release film. To produce the laminated film. The obtained laminated film is laminated on the back surface of the foam base material on which the acrylic pressure-sensitive adhesive layer 8 has been formed, with the acrylic pressure-sensitive adhesive layer facing the back surface of the foam base material to form a laminate. And the laminated body \¥0 2020/175368 14 卩 (: 171? 2020 /007043

By pressing with a rubber roller or the like, it is possible to obtain a double-sided pressure-sensitive adhesive tape having an acrylic pressure-sensitive adhesive layer on both sides of a foam base material and having the surface of the acrylic pressure-sensitive adhesive layer covered with a release film. However, when a foam substrate is used, the manufacturing method in which the adhesive is directly applied to the substrate may not be able to uniformly apply the adhesive when the thickness of the substrate varies or the surface roughness is large.

[0038] In addition, as the method for producing the double-sided pressure-sensitive adhesive tape of the present invention, the following methods may be mentioned.

First, two sets of laminated films were prepared in the same manner, and these laminated films were laminated on both sides of the foam substrate with the acrylic adhesive layer of the laminated film facing the foam substrate. To produce a laminate. Then, by pressing the laminated body with a rubber roller or the like, a double-sided adhesive tape having an acrylic adhesive layer on both sides of the foam base material and the surface of the acrylic adhesive layer covered with a release film is formed. obtain.

The application of the double-sided pressure-sensitive adhesive tape of the present invention is not particularly limited, but it can be particularly preferably used for fixing electronic device parts.

Such a double-sided pressure-sensitive adhesive tape of the present invention used for fixing electronic device parts is also one of the present invention.

Since the double-sided pressure-sensitive adhesive tape of the present invention is excellent in flexibility, impact resistance, and repulsion resistance, it has a great effect when used by being attached to a curved surface part of a part having a curved surface among electronic device parts. Demonstrate. The radius of curvature of the part with the above curved surface where the double-sided adhesive tape is attached is 5

Or more is preferable, 1

Is more preferable, and 100 or less!

Is more preferable,

The following is more preferable.

Such a double-sided pressure-sensitive adhesive tape of the present invention used for fixing electronic device parts, in which the radius of curvature of the double-sided pressure-sensitive adhesive tape-attached portion is not less than 5 01 01 and not more than 100 0 0! There is one.

In addition, the electronic device parts in which the double-sided adhesive tape of the present invention is attached to the curved surface and the radius of curvature are 5

Double-sided adhesive of the present invention in the following parts \¥0 2020/175368 15 卩 (: 171? 2020 /007043

An electronic device component to which a tape is attached is also one aspect of the present invention. Further, an electronic device including the electronic device component described above is also one aspect of the present invention. The shape of the double-sided pressure-sensitive adhesive tape of the present invention in these applications is not particularly limited, and examples thereof include a rectangle, a frame shape, a circle, an ellipse, and a donut shape.

Effect of the invention

[0042] According to the present invention, a double-sided adhesive tape having high flexibility, impact resistance and repulsion resistance, which can be suitably used for fixing electronic device parts and vehicle parts, and the double-sided adhesive tape. It is possible to provide electronic device parts and electronic devices using a tape.

Brief description of the drawings

[0043] [Fig. 1] Fig. 1 is a schematic diagram illustrating a cohesive strength test of a double-sided adhesive tape.

[Fig. 2] Fig. 2 is a schematic diagram for explaining the II 3!! Adhesive strength test of the double-sided adhesive tape.

[FIG. 3] A schematic diagram illustrating a drop impact test of a double-sided adhesive tape. MODE FOR CARRYING OUT THE INVENTION

[0044] Hereinafter, the embodiments of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0045] (Preparation of foam substrate ())

Linear low-density polyethylene resin 100 parts by weight, azodicarbonamide 3 parts by weight as a pyrolysis type foaming agent, 1 part by weight of zinc oxide as a decomposition temperature adjusting agent, and 2, 6-ge 1: as an antioxidant. — Butyl-cresol (0.5 parts by weight) was supplied to a single-screw extruder, melt-kneaded at 130 ^° and extruded as a raw sheet having a thickness of 180.

[0046] Next, the above-mentioned raw sheet is cross-linked by irradiating both sides with an electron beam having an accelerating voltage of 1501 <8.8 IV! The foamed sheet was continuously fed into the foaming furnace held at 10 to heat and foamed to obtain a foamed sheet.

It was stretched in the mouth to obtain a polyolefin foam having a thickness of 100.

[0047] (Foam Base Material (Mimi)) ~ (Preparation of [<)) \¥0 2020/175368 16 卩 (: 171? 2020 /007043

Amount of foaming agent added! 0.5 to 4.0 parts by mass, and the dose at the time of cross-linking was adjusted to 3.0 to 10.5 IV! “ ₃ . Foam base materials (Mimi) to ([<) having the thicknesses shown in Table 1 were obtained.

[0048] (Measurement of average major axis, average minor axis, and bubble aspect ratio of bubbles)

First, cut the foam base material in the direction of 504, soak it in liquid nitrogen for 1 minute, and then use a razor blade to cut it against the plane parallel to the IV! 0 direction and parallel to the IV! 0 direction. Cut in a vertical plane. Then, using a digital microscope (1 ^to 100 _ 900, manufactured by Keyence), take a magnified photograph of the cut surface at a magnification of 200 times,

For all cells existing in the range (thickness X 2 01 01 range)

The bubble size in the direction was measured. This operation was repeated 5 times, and the average bubble diameters in the IV!0 direction were calculated by averaging all the obtained bubble diameters. Next, the average cell diameter in the 0 direction was obtained by the same method except that the foam substrate was cut along a plane parallel to the 0 direction and perpendicular to the plane formed by the IV! 0 direction and the 0 direction. .. Of the obtained average bubble diameters in IV! 0 and 0 direction, the larger one was defined as the average major diameter of the bubbles, and the shorter one was defined as the average minor diameter. Further, the bubble aspect ratio (minor axis/major axis) was calculated from the average major axis and the average minor axis of all the obtained bubbles. The results are shown in Tables 1 and 2.

[0049] (Measurement of expansion ratio)

The obtained foam base material was measured by a method according to “3 <- 6 7 6 7” using an electronic hydrometer manufactured by Mirage Co., Ltd. The foaming ratio was calculated from the degree. The results are shown in Tables 1 and 2.

[0050] (Preparation of acrylic adhesive (3))

42 parts by weight of butyl acrylate in a reactor equipped with a thermometer, a stirrer, and a cooling tube,

2-Ethylhexyl acrylate 55 parts by weight, acrylic acid 3 parts by weight, 2-hydroxyethyl acrylate 0.2 parts by weight, and ethyl acetate 80 parts by weight were added, and the atmosphere was replaced with nitrogen. Then, 0.1 part by weight of azobisisoptyronitril was added as a polymerization initiator, and the mixture was polymerized at 60 ^° C. for 8 hours to obtain a solution of an acrylic copolymer. The weight average molecular weight of the obtained acrylic copolymer was measured by the method (3), and it was 11,000,000. 15 parts by weight of polymerized rosin ester and 25 parts by weight of ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) based on 100 parts by weight of the solid content of the acrylic copolymer contained in the obtained solution of the acrylic copolymer. Then, 1.5 parts by weight of an isocyanate crosslinking agent was added and stirred to obtain an acrylic pressure-sensitive adhesive (a). The measuring equipment and measuring conditions for polymerized rosin ester, isocyanate cross-linking agent and GPC were as follows. Polymerized rosin ester: D-1 35, Softening point 1 35 °C, Arakawa Chemical Co., Ltd. Isocyanate crosslinking agent: Coronate L45, Tosoh Corporation

Gel permeation chromatograph: e 2695 Sep a r a t i o n s M o d u I e (manufactured by W a t er s)

Detector: Differential refractometer (24 14, manufactured by Wa ter s)

Column: G PC K F-806 L (manufactured by Showa Denko KK)

Standard sample: STAN D RAD SM- 105, manufactured by Showa Denko KK

Sample flow rate: 1 m L/m i n

Column temperature: 40 °C

(Preparation of acrylic adhesive (b))

An acrylic pressure-sensitive adhesive (b) was obtained in the same manner as in the preparation of the acrylic pressure-sensitive adhesive (a), except that the amount of the isocyanate cross-linking agent added was 0.9 part by weight.

(Preparation of acrylic adhesive (c))

An acrylic pressure-sensitive adhesive (c) was obtained in the same manner as in the preparation of the acrylic pressure-sensitive adhesive (a), except that the amount of the isocyanate cross-linking agent added was 1.8 parts by weight.

(Preparation of acrylic adhesive (d))

An acrylic pressure-sensitive adhesive (d) was obtained in the same manner as in the preparation of the acrylic pressure-sensitive adhesive (a), except that the amount of the isocyanate crosslinking agent added was 1.6 parts by weight.

(Preparation of acrylic adhesive (e))

82 parts by weight of butyl acrylate, 10 parts by weight of ethyl acrylate, 5 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, 0.2 parts by weight of 2-hydroxyethyl acrylate in a reactor equipped with a thermometer, a stirrer and a cooling tube. , \¥0 2020/175368 18 卩 (: 171? 2020 /007043

Then, 80 parts by weight of ethyl acetate was added, the atmosphere was replaced with nitrogen, and then the reactor was heated to start reflux. Subsequently, 0.1 part by weight of azobisisobutyronitrile was added as a polymerization initiator into the reactor. The solution was refluxed for 5 hours to obtain a solution of an acrylic copolymer. The weight average molecular weight of the obtained acrylic copolymer was measured in the same manner as in the preparation of the acrylic pressure-sensitive adhesive (8), and it was 120,000.

15 parts by weight of polymerized rosin ester resin, 10 parts by weight of terpene phenol resin, and 10 parts by weight of rosin ester based on 100 parts by weight of the solid content of the acrylic copolymer contained in the obtained acrylic copolymer solution. Resin-based resin (10 parts by weight), ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) 1-25 parts by weight, and isocyanate-based crosslinking agent (1.8 parts by weight) were added and stirred to obtain an acrylic pressure-sensitive adhesive (Mitsumi). .. The following were used as the polymerized rosin ester-based resin, terpene phenol-based resin, rosin ester-based resin, and isocyanate-based cross-linking agent.

Polymerized rosin ester resin: 0-1 35, softening point 1 35 ° °, manufactured by Arakawa Chemical Industry Co., Ltd.

Terpene phenolic resin: Ding 1600, softening point 1600° 〇, manufactured by Yasuhara Chemical

Rosin ester resin:

7 5, Softening point 75 ^° 〇, Arakawa Chemical Co., Ltd. Isocyanate cross-linking agent: Coronate!_45, Tosoh

(Preparation of acrylic adhesive (dried))

In a reactor equipped with a thermometer, a stirrer, and a cooling pipe, 78 parts by weight of butyl acrylate,

19 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, 0.2 parts by weight of 2-hydroxyethyl acrylate, and 80 parts by weight of ethyl acetate were added, and after nitrogen substitution, the reactor was heated. The reflux started. Then, 0.1 part by weight of azobisisoptyronitrile was added as a polymerization initiator into the reactor. The solution was refluxed for 5 hours to obtain a solution of an acrylic copolymer. The weight average molecular weight of the obtained acrylic copolymer was measured in the same manner as in the preparation of the acrylic pressure-sensitive adhesive (3), and it was 910,000. \¥02020/175368 19 卩 (: 171? 2020 /007043

15 parts by weight of polymerized rosin ester resin, 10 parts by weight of terpene phenol resin, and 10 parts by weight of rosin ester based on 100 parts by weight of the solid content of the acrylic copolymer contained in the obtained acrylic copolymer solution. Resin (10 parts by weight), ethyl acetate (manufactured by Fuji Chemical Co., Ltd.) 125 parts by weight, and isocyanate crosslinking agent 2.2 parts by weight were added and stirred to obtain an acrylic adhesive. The following were used as the polymerized rosin ester-based resin, terpene phenol-based resin, rosin ester-based resin, and isocyanate-based cross-linking agent.

Polymerized rosin ester resin: 0-1 35, softening point 1 35° 〇, manufactured by Arakawa Chemical Industry Co., Ltd.

Terpene phenolic resin: Ding 1 160, softening point 1 60° 〇, made by Yasuhara Chemical

Rosin ester resin:

75, Softening point 75 ^° 〇, Arakawa Chemical Industry Co., Ltd. Isocyanate cross-linking agent: Coronate !_45, Tosoh Corporation

(Preparation of acrylic adhesive (9))

Acrylic adhesive (h) was prepared in the same manner as for the preparation of acrylic adhesive (h), except that the amount of butyl acrylate was changed to 60 parts by weight and the amount of 2-ethylhexyl acrylate was changed to 37 parts by weight. 9) got The weight average molecular weight was 530,000.

(Preparation of acrylic adhesive ())

An acrylic pressure-sensitive adhesive) was obtained in the same manner as in the preparation of the acrylic pressure-sensitive adhesive (3), except that the amount of the isocyanate crosslinking agent added was 2.0 parts by weight.

(Measurement of storage elastic modulus)

The obtained acrylic pressure-sensitive adhesive, viscoelastic spectrometer (Keisoku Seigyo Co., 0 eighty-one 200) using a 1 〇 / min TeihayaNoboru temperature tensile mode, one 40 under the conditions of 1 01 ^~ 1 Å The dynamic viscoelastic spectrum from 0° to 1400° was measured. From the obtained dynamic viscoelastic spectrum, the storage elastic modulus at 23° 〇 (〇' (2

The storage elastic moduli (○'(1 40°○) at 3°○) and 140°○ were determined. The results are shown in Tables 1 and 2. \¥02020/175368 20 units (: 171? 2020 /007043

(Measurement of gel fraction)

The acrylic adhesive obtained was scraped off with 0.19 and washed with ethyl acetate.

It was soaked in a bowl and shaken with a shaker for 24 hours at a temperature of 23°C and 120 ". After shaking, absorb ethyl acetate and ethyl acetate using a metal mesh (opening #200 mesh). The swollen acrylic adhesive was separated, and the separated adhesive composition was dried for 1 hour under the condition of 110 ^° 〇 The weight of the dried acrylic adhesive including the metal mesh was measured, The gel fraction of the acrylic adhesive was calculated using the following formula.

Gel fraction (% by weight) = 100 X

/ 〇

(○: initial acrylic adhesive weight,

: Weight of acrylic adhesive including metal mesh after drying, ₂ : Initial weight of metal mesh)

(Example 1)

Prepare a release paper with a thickness of 150, apply acrylic adhesive (8) on the release treated surface of this release paper, and dry it at 100 ° 〇 for 5 minutes to form a 50-layer acrylic adhesive layer. Formed. This acrylic pressure-sensitive adhesive layer is used as a foam base material (8) (polyethylene resin, average major axis and minor axis of cells are 1 32, 9 0 0 1, foaming ratio is ³ 0 0 1 3/9, thickness 1 0, respectively). It was attached to the surface of the one that was adjusted to ◯). Then, in the same manner, the same acrylic pressure-sensitive adhesive layer as the above was attached to the opposite surface of the foam substrate (). As a result, a double-sided adhesive tape having a tape thickness shown in Table 1 covered with a release paper having a thickness of 150^^ was obtained.

(Examples 2 to 12, Comparative Examples 1 to 7)

A double-sided pressure-sensitive adhesive tape was obtained in the same manner as in Example 1 except that the foam substrate and the acrylic pressure-sensitive adhesive were changed to those shown in Tables 1 and 2.

[0062] (25% compression strength measurement)

About the obtained double-sided adhesive tape"

The intensity was calculated. The results are shown in Tables 1 and 2.

(Amount of deviation due to cohesive strength test)

Double-sided double-sided adhesive tape 1 cut on 2001111X40111111 as shown in Figure 1. \¥0 2020/175368 21 卩 (: 171? 2020 /007043

Let Next, one end of one of the stainless steel plates 21 was fixed, and one end of the Mitsume film 22 was pulled horizontally by a weight 23 of 209 at a temperature of 23° for 3 minutes. Then, the displacement amount of the double-sided pressure-sensitive adhesive tape 1 displaced in the pulling direction was measured. The results are shown in Tables 1 and 2.

[0064] <Evaluation>

The double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0065] (1)

Evaluation of power

II 3 1 ^to 1 adhesive strength of the obtained double-sided pressure-sensitive adhesive tape was measured by the following method. II 3 1 ^to 1 Adhesive force is the adhesive force when a force is applied in a direction perpendicular to the adhesive surface. II 3 1 ^~ 1 Adhesive strength changes with pressure even with the same double-sided tape. This is because the pressure changes the degree of adhesion between the adhesive surface of the tape and the interface of the adherend. Therefore, the higher the pressure, the higher the degree of adhesion and the higher the 11 3 1 ^to 1 adhesive force. In other words, the softer the double-sided tape is, the lower the adhesive force between the adhesive surface and the adherend interface is not lost even when a low pressure is applied, and the difference between the adhesive force when a high pressure is applied is reduced. Therefore, by measuring the PUSH adhesive strength, it can be used as an index to measure the flexibility of the double-sided adhesive tape. Fig. 2 shows a schematic diagram of the 11 3 1 ^to 1 adhesion test of the double-sided adhesive tape. The outer diameter of the obtained double-sided adhesive tape 1

Punched into a square shape with an inner diameter of 4 4 0 1 1 5 9 0 1 0 1

did. Then, as shown in Fig. 2 (3), 3 8

The test piece from which the release paper had been peeled off was attached to a stainless steel plate 4 having a square hole and a thickness of 2 so that the square hole was located approximately in the center. Then, a glass plate 3 having a thickness of 500 1 01 700 1 01 01 and a thickness of 4 01 01 was attached from the upper surface of the test piece so that the test piece was located at the substantially center, and the test apparatus was assembled.

Then, from the stainless plate side located on the upper surface of the test equipment, pressure of 0. 1 1\/1 3 \¥02020/175368 22 卩 (: 171? 2020 /007043

Was applied for 10 seconds, the upper and lower stainless steel plates and the test piece were pressure-bonded, and left at room temperature for 24 hours.

After leaving it for a while, as shown in Fig. 2 (Slung), turn over the test device that was made, fix it on the support, and insert a square stainless steel rod into the square hole of the test piece through the square hole. A load of 5 was slowly applied at a speed of 1 001111/111, and the value of the load when the test piece and the glass plate were peeled off by the load was measured. this

Adhesive strength (low pressure bonding).

Then, set the crimping conditions to 〇.

II 31 ^~ 1 Adhesiveness except for 10 seconds

The measurement was performed in the same manner as (low pressure bonding) to obtain P US H adhesive strength (normal). From the obtained results, (100 X II 31 ^to 1 adhesive strength (low pressure bonding)/II 31 ^to 1 adhesive strength (normal)) was calculated and evaluated according to the following criteria.

◎: 95% or more

0: 92% or more and less than 95%

△ = 73% or more and less than 92%

X: less than 73%

[0066] (2) Evaluation of impact resistance (drop impact test)

Figure 3 shows a schematic diagram of the drop impact test for double-sided adhesive tape. Punching the obtained double-sided adhesive tape 1 into a square shape with an outer diameter of 4601111X6 101111 and an inner diameter of 4401111X59111111,

did. Then, as shown in Fig. 3 (3),

The test piece from which the release paper had been peeled off was attached to the stainless steel plate 4 so that the square hole was located approximately in the center. Then, from the top surface of the test piece, 500101 x 700101,

The glass plate 3 was attached to the test piece so that the test piece was located almost in the center, and the test device was assembled.

After that, from the side of the stainless steel plate located on the upper surface of the test equipment,

Was applied for 10 seconds to crimp the upper and lower stainless steel plates to the test piece, and left at room temperature for 24 hours.

After leaving it for a while, as shown in Fig. 3 (slung), turn over the test device that was made and fix it on the support base. \¥02020/175368 23 卩 (: 171? 2020 /007043

Then, an iron ball 6 weighing 1 509, which is large enough to pass through the square hole, was dropped so as to pass through the approximate center of the square hole. The height at which the iron ball is dropped is gradually increased, and the height at which the iron ball is dropped when the test piece and the glass plate are peeled off by the impact applied by the drop of the iron ball

Was measured.

The obtained measured value was divided by the thickness () of the double-sided adhesive tape to calculate a value, and the impact resistance was evaluated according to the following criteria.

○: ○ 0.16 or more and less than 0.2

△: ○ or more and less than ○.16

X: less than 0.1

[0067] (3) Evaluation of gap followability

The gap followability of the obtained double-sided pressure-sensitive adhesive tape was evaluated by the following method. In the evaluation of gap followability, a spacer is intentionally squeezed between the adherends that have been bonded together, and tensile force is applied in the thickness direction of the double-sided tape. At this time, the tape is subjected to a stress to return to its original shape.In this state, the rebound resistance is evaluated by measuring the presence or absence of peeling of the double-sided adhesive tape and measuring the elongation of the foam base material and adhesive. You can In other words, the tape is more resistant to peeling when it is not peeled off, and the more the foam base material is stretched rather than the pressure-sensitive adhesive, the less stress is applied to the interface between the pressure-sensitive adhesive and the adherend. It will be.

The obtained adhesive tape is 1 0111X 1

Then, it was sandwiched between two polycarbonate plates having a thickness of 1 2501111X50111111 and a thickness of 100! to obtain a laminate. From the top surface of the obtained laminate 〇.

Was applied for 10 seconds to bond the double-sided adhesive tape and the polycarbonate plate. Immediately after pressure bonding, an aluminum plate having a thickness of 1.5 times the thickness of the double-sided adhesive tape was kneaded between the laminated polycarbonate plates and the elongation of the foam base material and the acrylic adhesive layer of the adhesive tape was measured. .. The gap followability was evaluated according to the following criteria.

◎: Expansion of the foam substrate is 50% or more

◯: The foam base material is stretched, and the stretch is less than 50% \¥0 2020/175 368 24 卩 (: 17 2020 /007043

△: Foam base material is not stretched

X: There is a part that is peeled off at the interface

[0068]

[¾ji

\¥0 2020/175368 26 卩 (: 171? 2020 /007043

[0069] [Table 2]

Industrial availability

[0070] According to the present invention, a double-sided adhesive tape having high flexibility, impact resistance, and repulsion resistance, which can be suitably used for fixing electronic device parts and vehicle parts, and the double-sided adhesive tape To provide electronic equipment parts and electronic equipment using tape \\0 2020/175 368 27 卩 (: 171? 2020 /007043

You can

Explanation of symbols

[0071] 1 Double-sided adhesive tape

2 1 Stainless steel plate

2 2 Ming Film

2 3 weight

3 glass plate

4 stainless steel plate

5 load

6 iron ball

Claims

\¥0 2020/175 368 28 卩 (: 17 2020 /007043 Claims

[Claim 1] A double-sided adhesive tape having an acrylic adhesive layer on both sides of a foam substrate,

The average major axis of the bubbles of the foam substrate is 1 5 0 or less, the 25% compressive strength of the double-sided adhesive tape is at 5 OO k P ₃ below, the double-sided adhesive tape, foam substrate thickness / Double-sided adhesive tape thickness is 〇.

5 or more,

The double-sided pressure-sensitive adhesive tape is a double-sided pressure-sensitive adhesive tape in which the amount of deviation in the cohesive strength test is 35 or more and 110 or less.

[Claim 2] The expansion ratio of the foam substrate is 20

^3/9 or more 5_Rei_rei! ^3/9 Ru der less double-sided pressure-sensitive adhesive tape of claim 1, wherein.

[Claim 3] Acrylic pressure-sensitive adhesive constituting the acrylic adhesive layer is storage modulus at 2 3 ^° 〇 is 4 X 1 0 5 3 or less, 1 4 savings built modulus at 0 ° 〇 is 3 X 1 〇 ⁴ is 3 or more, according to claim 1 or 2 sided pressure-sensitive adhesive tape according.

[Claim 4] The double-sided adhesive tape according to claim 1, which is used for fixing electronic device parts.

[Claim 5] The double-sided pressure-sensitive adhesive tape according to claim 1, 2 or 3, which has a radius of curvature of not less than 50! and not more than 100!

[Claim 6] An electronic device component, wherein the double-sided adhesive tape according to Claim 1, 2 or 3 is attached to a curved surface portion.

[Claim 7] The radius of curvature is

An electronic device component having the double-sided adhesive tape according to claim 1, 2 or 3 attached to the lower part.

[Claim 8] An electronic device comprising the electronic device component according to claim 6 or 7.