JPWO2017208838A1 - Thermally expandable adhesive tape and article - Google Patents

Abstract

[Problem] The problem to be solved by the present invention is that even when the adherends are repeatedly expanded or contracted at different ratios when left in an environment with a large temperature change, the adherends It is to provide a thermally expandable adhesive tape capable of preventing loosening of bonding, generation of abnormal noise due to vibration thereof, and separation of the adherends.
[Solution] The present invention relates to a thermally expandable adhesive tape used for fixing an adherend (d1) and an adherend (d2) in a fitted state, wherein the adherend (d1) The linear expansion coefficient (d1-1) and the linear expansion coefficient (d2-1) of the adherend (d2) are [linear expansion coefficient (d2-1) / linear expansion coefficient (d1-1)] = 2. The present invention relates to a heat-expandable adhesive tape characterized by being in the range of ˜1000.

Description

  The present invention relates to a thermally expandable adhesive tape and an article used for fixing two or more adherends having different linear expansion coefficients.

  Various products such as automobiles and electric devices are configured by joining a large number of members. As a method of joining the members, there are a method using an adhesive or an adhesive tape, a method of fitting the members together, and a method using the adhesive is, for example, when accommodating and fixing a coil conductor in a slot of a stator core. In addition, a method of filling and fixing these gaps with an insulating fixing resin is known (for example, see Patent Document 1).

  However, the method of fixing the adhesive by filling the gaps between the adherends has a problem that the adhesive easily protrudes particularly when the gap is narrow. Moreover, when fixing the said adherends with an adhesive tape, since it is necessary to match the magnitude | size of the clearance gap between the said adherends, and the thickness of an adhesive tape, the working efficiency for fixing the adherends falls. There was a problem to make.

  Selection of the joining method of the members can be appropriately performed in consideration of various conditions such as the shape, material, and usage environment of the members. For example, when one of the members is a cylindrical member, By fitting a lid-shaped member corresponding to the cylindrical shape as a member, they can be joined.

  As the member having the above-described shape, for example, an exterior member (cylindrical member) constituting a small motor mounted on a movable part of an automobile and its lid-like member can be cited (FIG. 1).

  The tubular member is usually made of a metal such as stainless steel, and the lid-like member is often made of a resin such as plastic.

  However, since the metal and the resin generally expand or contract at different ratios when heated or cooled, the cylindrical member and the lid are exposed when exposed to an environment with a large temperature change for a long time. As a result, there is a case in which a gap is generated between the member and the member, causing abnormal noise due to vibration of the member, dropping of the member, and the like.

Japanese Patent No. 5157296

  The problem to be solved by the present invention is that even when the adherends are repeatedly expanded or contracted at different ratios when left in an environment with a large temperature change, the bonding between the adherends is difficult. An object of the present invention is to provide a thermally expandable adhesive tape capable of preventing loosening, generation of abnormal noise due to vibration thereof, and separation of the adherends.

  The inventors of the present invention are thermally expandable adhesive tapes used when the adherend (D1) and the adherend (D2) are fixed in a fitted state, and the wire of the adherend (D1) The expansion coefficient (d1) and the linear expansion coefficient (d2) of the adherend (D2) are in the range of [linear expansion coefficient (d2) / linear expansion coefficient (d1)] = 2 to 1000. The above problems were solved by the thermally expandable adhesive tape.

  The thermal expansion adhesive tape of the present invention has excellent adhesive strength after thermal expansion, and is a case where the adherend repeatedly expands or contracts at different ratios when left in an environment with a large temperature change for a long period of time. In addition, loosening of bonding between the adherends, generation of abnormal noise due to vibration thereof, and separation of the adherends can be prevented.

It is a conceptual diagram which shows the shape of a lid-shaped member. It is a conceptual diagram showing an article in which a cylindrical member and a lid-like member are fitted, an article in which the cylindrical member and the lid-like member are fixed with a heat-expandable adhesive tape, and an article after it has been subjected to a thermal cycle test. is there.

  The thermal expansion adhesive tape of the present invention is used when the adherend (D1) and the adherend (D2) are fixed in a fitted state, and the linear expansion of the adherend (D1). The coefficient (d1) and the linear expansion coefficient (d2) of the adherend (D2) are in the range of [linear expansion coefficient (d2) / linear expansion coefficient (d1)] = 2 to 1000. To do.

  The adherend (D1) and the adherend (D2) fixed with the thermally expandable adhesive tape of the present invention have different linear expansion coefficients. When an article fixed in a state where adherends having different linear expansion coefficients are fitted to each other is placed in an environment with a large temperature change for a long time, for example, either one of the adherends (D1) and (D2) or Both of them repeatedly contract or expand, and eventually a gap may be formed in the fitting parts (the parts joined in a state where the adherends are joined together) of the adherends (D1) and (D2). .

  In the present invention, among two or more adherends having different linear expansion coefficients, the linear expansion coefficient (d1) of the adherend (D1) and the linear expansion coefficient (d2) of the adherend (D2) are: , [Linear expansion coefficient (d2) / Linear expansion coefficient (d1)] = 2 to 1000. This is a case where the gap is formed by using a thermally expandable adhesive tape for fixing the adherend. However, it is possible to prevent looseness of bonding between the adherends, generation of abnormal noise due to vibration thereof, and separation of the adherends.

  Here, the linear expansion coefficient (d1) of the adherend (D1) and the linear expansion coefficient (d2) of the adherend (D2) are measured in either JIS Z 2285: 2003 or JIS K 7197: 2012. Refers to the value. Specifically, when a metal member is used as the adherend (D1) or the adherend (D2), its linear expansion coefficient is measured based on JIS Z 2285: 2003. On the other hand, when a resin member is used as the adherend (D1) or adherend (D2), the linear expansion coefficient is measured based on JIS K 7197: 2012. The temperature range at the time of the measurement can be performed in the range of −150 ° C. to 600 ° C. and 0.01 to 100 ° C./min.

  Further, when the linear expansion coefficients of the adherends (D1) and (D2) are different in the flow direction and the width direction, the maximum value when the linear expansion coefficient in each direction is measured is set to the adherend ( The linear expansion coefficients (d1) and (d2) of D1) and the adherend (D2) were used, respectively.

  As the adherends (D1) and (D2), those having a [linear expansion coefficient (d2) / linear expansion coefficient (d1)] of 2 to 100 are preferably used, and those having 2 to 50 are used. When using in combination with a heat-expandable adhesive tape having an adhesive layer having an expansion coefficient in a suitable range, which will be described later, It is more preferable because separation of the adherends can be more effectively prevented regardless of the expansion or contraction of D1) and (D2).

As the adherend (D1) and adherend (D2), for example, cemented carbide (linear expansion coefficient 5.5 × ¹⁰ -6 ^{K -1),} stainless steel (SUS430, linear expansion coefficient of 10.4 × 10 ^{- 6} K ⁻¹ ), carbon steel (linear expansion coefficient 11.0 × 10 ⁻⁶ K ⁻¹ ), high-speed steel (linear expansion coefficient 11.2 × 10 ⁻⁶ K ⁻¹ ), iron (linear expansion coefficient 12.1) × 10 ⁻⁶ K ⁻¹ ), gold (linear expansion coefficient 14.2 × 10 ⁻⁶ K ⁻¹ ), copper (linear expansion coefficient 16.6 × 10 ⁻⁶ K ⁻¹ ), stainless steel (SUS304, linear expansion coefficient) Metal members such as 17.3 × 10 ⁻⁶ K ⁻¹ ), brass (linear expansion coefficient 19.0 × 10 ⁻⁶ K ⁻¹ ), aluminum (linear expansion coefficient 23.0 × 10 ⁻⁶ K ⁻¹ ), such as polyethylene terephthalate (linear expansion coefficient 15.0 × ¹⁰ -6 ^{K -1),} polyether ether Ketones (linear expansion coefficient ^{40 × 10 -6 ~47 × 10 -6} K -1), polyphenylene sulfide (linear expansion coefficient ^{40 × 10 -6 ~49 × 10 -6} K -1), fluororesin (linear expansion coefficient 50 × 10 ^{−6 to} 90 × 10 ⁻⁶ K ⁻¹ ), polycarbonate (linear expansion coefficient 70 × 10 ⁻⁶ to 80 × 10 ⁻⁶ K ⁻¹ ), polyacetal resin (linear expansion coefficient 70 × 10 ^{−6 to} 130 ×) 10 ⁻⁶ K ⁻¹ ), 6-nylon (linear expansion coefficient 80 × 10 ⁻⁶ K ⁻¹ ), 6.6 nylon (linear expansion coefficient 80 × 10 ^{−6 to} 100 × 10 ⁻⁶ K ⁻¹ ), ABS resin (linear expansion coefficient 80 × 10 ^{−6 to} 100 × 10 ⁻⁶ K ⁻¹ ), high density polyethylene (linear expansion coefficient 100 × 10 ^{−6 to} 120 × 10 ⁻⁶ K ⁻¹ ), polypropylene (linear expansion coefficient) 110 × ¹⁰ -6 to 1 0 × ¹⁰ -6 ^{K -1),} the line of polyethylene (among such resin member in linear expansion coefficient ^{120 × 10 -6 ~150 × 10 -6} K -1) and the like, wherein [the adherend (D1) The adherend satisfying the range of expansion coefficient (d2) / linear expansion coefficient (d11) of the adherend (D2)] = 2 to 1000 can be appropriately selected and used in combination.

  More specifically, the metal member is preferably used as the adherend (D1), and the resin member is preferably used in combination as the adherend (D2).

  As the adherends (D1) and (D2), those having a plate shape, a concave shape, a convex shape, a curved surface shape, a cylindrical shape, a lid shape, etc. can be used. What has each the shape which can fit (D2) can be used. More specifically, as the adherends (D1) and (D2), either one has a cylindrical shape, and the other has a lid shape corresponding to the opening portion of the cylindrical shape. preferable.

  Here, the fitting refers to a state in which adherends are joined together, and more preferably, a shape y corresponding to the shape x of one of the adherends (can be fitted to the shape x). A state in which the adherend having the shape y) is combined. For example, if it is the said cylindrical member and a lid-shaped member, the lid-shaped member is inserted in the opening part of the said cylindrical-shaped member, and the state in which they were fixed is pointed out. At that time, the adherends may be in a state where there is no gap, or may be in a state where a gap is partially present.

  The thermally expandable adhesive tape used when the adherends (D1) and (D2) are fixed in a fitted state is, for example, directly or via another layer on one side of the adhesive layer (A). An adhesive tape having an adhesive layer (B), the expansion rate in the thickness direction of the adhesive layer (A) after leaving the adhesive tape in an environment of 130 ° C. for 1 hour The thickness of the subsequent adhesive layer (A) / the thickness of the adhesive layer (A) before standing] × 100 is 200% or more, and the expansion in the thickness direction of the adhesive layer (B) The ratio [thickness of the adhesive layer (B) after standing / thickness of the adhesive layer (B) before standing] × 100 is 120% or less.

  In addition, as the thermally expandable adhesive tape of the present invention, it is preferable to use one having an expansion coefficient of 150% to 1000% of the entire adhesive tape after leaving it in an environment of 130 ° C. for 1 hour. It is more preferable to use a material in the range of% to 500% in order to develop a further excellent adhesive strength.

  In addition, the expansion coefficient is the ratio of the heat-expandable adhesive tape to the total thickness of the heat-expandable adhesive tape before the standing (before expansion) when the heat-expandable adhesive tape is left in an environment of 130 ° C. for 1 hour. It refers to the ratio of the thickness of the entire adhesive tape ((the thickness of the entire adhesive tape after expansion). Specifically, the expansion coefficient refers to a value calculated by the following method.

  The thickness of the thermally expandable adhesive tape before being left for 1 hour in a 130 ° C. environment (before expansion) is measured in a 23 ° C. environment.

  The adhesive tape is left in an environment of 130 ° C. for 1 hour.

  The thermally expandable adhesive tape after being left is taken out in an environment of 23 ° C., and the thickness of the entire adhesive tape expanded immediately is measured.

The expansion coefficient is calculated based on the measurement result and the following formula.
[Thickness of the thermally expandable adhesive tape after being left / thickness of the thermally expandable adhesive tape before being left] × 100

  The adhesive layer (A) constituting the heat-expandable adhesive tape is a layer that can be expanded by applying a stimulus such as heat or light.

  As the adhesive layer (A), when the adhesive tape is left in an environment of 130 ° C. for 1 hour, the expansion rate in the thickness direction of the adhesive layer (A) [the adhesive layer after being left ( The thickness of A) / the thickness of the adhesive layer (A) before standing] × 100 is preferably 200% or more.

  The expansion coefficient is preferably 250% or more, and more preferably 250% to 1000%. If the adhesive tape has the adhesive layer (A) having the expansion coefficient, for example, even when the height (thickness) of the gap of one adherend is large, the other adherend is placed in the gap. The body can be suitably fixed, or the space can be filled with the adhesive tape.

  The expansion rate of the adhesive layer (A) is the thickness of the adhesive layer (A) before being left (before expansion) when the thermally expandable adhesive tape is left in an environment of 130 ° C. for 1 hour. It refers to the ratio of the thickness of the adhesive layer (A) after being left to stand ((the thickness of the adhesive layer (A ′) formed by expansion)). The value calculated by the following method.

  The thickness of the adhesive layer (A) constituting the thermally expandable adhesive tape before being left for 1 hour in a 130 ° C. environment (before expansion) is measured in a 23 ° C. environment.

  The adhesive tape is left in an environment of 130 ° C. for 1 hour.

  The left thermally expandable adhesive tape is taken out in an environment of 23 ° C., and the thickness of the adhesive layer (A ′) formed by immediately expanding the adhesive layer (A) is measured.

The expansion coefficient is calculated based on the measurement result and the following formula.
[The thickness of the adhesive layer (A) constituting the thermally expandable adhesive tape after standing] [The thickness of the adhesive layer (A ′) formed by swelling] / Adhesion constituting the thermally expandable adhesive tape before standing Thickness of agent layer (A)] × 100

  The thickness of the adhesive layer (A) constituting the thermally expandable adhesive tape is preferably 1 μm or more, more preferably in the range of 10 μm to 250 μm, and further preferably in the range of 20 μm to 150 μm. Preferably, the range of 30 μm to 70 μm is particularly preferable in order to obtain a further excellent adhesive strength.

  On the other hand, the thickness of the adhesive layer (A ′) formed by expanding the adhesive layer (A) is preferably in the range of 20 μm to 2500 μm, and in the range of 40 μm to 1500 μm. It is preferable for obtaining even better adhesive strength. The adhesive layer (A ′) preferably has a porous structure.

  Further, as the thermally expandable adhesive tape, it is preferable to use one having a thickness of the adhesive layer (A) of 10% or more with respect to the total thickness of the thermally expandable adhesive tape, 30 It is easier to use one that is at least% because it is easier to fix the other adherend in the gap of one adherend or to fill the gap with the thermally expandable adhesive tape. preferable.

  As the adhesive layer (A), as described above, a layer that can be expanded by applying a stimulus such as heat or light can be used. Specifically, a layer containing various resins and an expansion agent is used. be able to.

  The adhesive layer (A) can be formed, for example, by applying an adhesive composition (a) containing the resin and an expanding agent to a release liner or the like and drying it.

  As the adhesive composition (a) that can be used for forming the adhesive layer (A), as described above, a composition containing a resin, an expansion agent, and a solvent as required can be used.

  As the resin, an epoxy resin, a urethane resin, a silicone resin, a phenol resin, a urea resin, a fluororesin, an acrylonitrile resin, an acrylic resin, a styrene resin, a vinyl resin such as a butadiene resin, or the like is used alone or in combination of two or more. be able to.

  Among these, it is preferable to use a thermosetting resin as the resin, and it is preferable to use an epoxy resin, which has excellent heat resistance after expansion, and the expanded adhesive layer (A ′) is remarkably over time. It is more preferable for obtaining a heat-expandable adhesive tape capable of preventing shrinkage.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, hindered-in type epoxy resin, biphenyl type epoxy resin, alicyclic epoxy resin, triphenylmethane type epoxy resin, and phenol novolac. Type epoxy resin, cresol novolak type epoxy resin, naphthol novolak type epoxy resin, dicyclopentadiene / phenol epoxy resin, alicyclic amine epoxy resin, aliphatic amine epoxy resin, and CTBN modification (carboxy-terminated butadiene nitrile modification) Halogen-modified epoxy resins or the like can be used alone or in combination of two or more, and the use of a cresol novolac type epoxy resin can be caused by the stimulation. Zhang easy and preferable because it can hold the adhesive strength is excellent even after expansion.

  It is preferable that 10 mass%-99 mass% of thermosetting resins, such as the said epoxy resin, are contained with respect to the said adhesive bond layer (A) whole.

  Moreover, it is preferable to use what contains a swelling agent as said adhesive composition (a), when forming the adhesive bond layer (A) which can be expanded by the said irritation | stimulation.

  The expansion agent is preferably one that can form a porous structure as the adhesive layer (A ′) after expansion, such as ammonium carbonate, ammonium hydrogen carbonate, ammonium nitrite, ammonium borohydride, azide, and the like. Inorganic compounds, fluorinated alkanes such as trichloromonofluoromethane, azo compounds such as azobisisobutyronitrile, hydrazine compounds such as paratoluenesulfonyl hydrazide, semicarbazide compounds such as p-toluenesulfonyl semicarbazide, 5-morpholyl-1,2 Triazole compounds such as 3,3,4-thiatriazole and N-nitroso compounds such as N, N′-dinitrosotephthalamide can be used.

  Further, as the expansion agent, for example, an expandable capsule such as a thermally expandable capsule in which a hydrocarbon solvent is microencapsulated can be used. As the expansion agent, it is preferable to use a material capable of generating gas and expanding at a temperature around the softening point of the resin.

  As the expansion agent, use of a thermally expandable capsule in which a hydrocarbon solvent is microencapsulated among the above is used, for example, to inhibit the curing of the epoxy resin, or to form an adhesive layer (A ) Is preferable for preventing deterioration and the like.

  As the thermally expandable capsule, a capsule having a volume after expansion (volume expansion coefficient) of 6 times to 60 times with respect to the volume of the capsule before expansion when heated in a preferable heating temperature range described later. Is preferred.

  Commercially available products of the above-mentioned thermally expandable capsules include, for example, EXPANSEL (manufactured by Nippon Philite Co., Ltd.), Matsumoto Microsphere (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), microsphere (manufactured by Kureha Co., Ltd.), die form (large) Nissei Chemical Industry Co., Ltd.), Advancel (manufactured by Sekisui Chemical Co., Ltd.) and the like.

  The amount of the expansion agent used, preferably the amount of the thermally expandable capsule, is preferably in the range of 0.3% by mass to 40% by mass with respect to the total amount of the adhesive layer (A). More preferably, it is in the range of 0.0 mass% to 30 mass%, and the range of 3.0 mass% to 20 mass% is expanded to a sufficient volume for filling the voids of the adherend. It is preferable for obtaining a heat-expandable adhesive tape that can be maintained and can maintain an even better adhesive strength.

  As said adhesive composition (a), what contains a hardening | curing agent, a hardening accelerator, etc. other than what was mentioned above as needed can be used.

  Examples of the curing agent include bisphenol A, bisphenol F, bisphenol AD, hydroquinone, resorcin, methyl resorcin, biphenol, tetramethylbiphenol, dihydroxynaphthalene, dihydroxydiphenyl ether, phenol novolac resin, bisphenol A novolac resin, dicyclopentadiene phenol resin. Various polyphenol resins such as terpene phenol resin, naphthol novolac resin, biphenyl phenol resin, polyhydric phenol resins obtained by condensation reaction of various phenols with various aldehydes such as hydroxybenzaldehyde, crotonaldehyde, glyoxal, And a modified phenol obtained by polycondensation of heavy oil or pitch, phenol and formaldehyde compounds Various phenolic resins such as resins, acid anhydrides such as methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, methylnadic acid, amines such as diethylenetriamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, dicyandiamide, etc. Can be used.

  Examples of the curing accelerator include imidazoles such as 2-methylimidazole, 2-methyl-4-ethylimidazole, and 2-phenylimidazole; 1,8-diazabicyclo [5.4.0] undecene-7, triethylenediamine, benzyl Tertiary amines such as dimethylamine; organic phosphines such as tributylphosphine and triphenylphosphine can be used alone or in combination of two or more.

  Moreover, as said thermally expansible adhesive tape, what has an adhesive bond layer (B) on the single side | surface of the said adhesive bond layer (A) is used. The adhesive layer (B) may be directly laminated on one surface side of the adhesive layer (A), or may be laminated via another layer such as a so-called base material. .

  As the adhesive layer (B), when the thermally expandable adhesive tape is allowed to stand in an environment of 130 ° C. for 1 hour, the expansion rate in the thickness direction of the adhesive layer (B) [adhesion after the standing] The thickness of the adhesive layer (B) / the thickness of the adhesive layer (B) before standing]] × 100 is 120% or less.

  The expansion ratio of the adhesive layer (B) is preferably 115% or less, and more preferably 100% to 115%.

  If it is a heat-expandable adhesive tape having the adhesive layer (B) having the expansion coefficient, it is possible to maintain excellent adhesive strength to the adherend even after the adhesive layer (A) has expanded. it can.

  The expansion rate of the adhesive layer (B) is based on the thickness of the adhesive layer (B) before being left standing when the thermally expandable adhesive tape is left in an environment of 130 ° C. for 1 hour. It refers to the ratio of the thickness of the adhesive layer after being left standing.

  In addition, the expansion coefficient of the adhesive layer (B) is based on the thickness of the adhesive layer (B) before leaving when the thermally expandable adhesive tape is left in an environment of 130 ° C. for 1 hour. It refers to the ratio of the thickness of the adhesive layer (B ′) after being left. Specifically, the expansion coefficient indicates a value calculated by the following method.

  The thickness of the adhesive layer (B) constituting the heat-expandable adhesive tape before being left for 1 hour in a 130 ° C. environment (before expansion) is measured in a 23 ° C. environment.

  The thermally expandable adhesive tape is left in an environment of 130 ° C. for 1 hour.

  The thermally expandable adhesive tape after being left is taken out in a 23 ° C. environment, and the thickness of the adhesive layer (B ′) corresponding to the adhesive layer (B) is immediately measured.

The expansion coefficient is calculated based on the measurement result and the following formula.
[The thickness of the adhesive layer (B ′) constituting the adhesive tape after being left / the thickness of the adhesive layer (B) constituting the adhesive tape before being left] × 100

  The thickness of the adhesive layer (B) is preferably in the range of 5 μm to 150 μm, and more preferably in the range of 10 μm to 100 μm, in order to express even better adhesive strength.

  The thickness of the adhesive layer (B ′) after being left for 1 hour in the environment of 130 ° C. varies within the above expansion coefficient range as compared with the thickness of the adhesive layer (B) before being left standing. May be. The thickness of the adhesive layer (B ′) is preferably in the range of 1 μm to 150 μm, and more preferably in the range of 5 μm to 100 μm, in order to express even better adhesive strength.

  Moreover, as said adhesive bond layer (B), the layer which has adhesiveness or adhesiveness is mentioned, For example, a thermosetting adhesive bond layer, a pressure sensitive adhesive layer, etc. are mentioned.

  The said adhesive bond layer (B) can be formed using the adhesive composition (b) which can form the layer which has adhesiveness or adhesiveness, for example.

  As said adhesive composition (b), what contains adhesive resin and the hardening | curing agent as needed, for example can be used. In addition, since it is preferable that the adhesive bond layer (B) formed using the said adhesive composition (b) has a low expansion coefficient as above-mentioned, it can be used when forming the said adhesive bond layer (A). It is preferable that the swelling agent illustrated as a thing does not contain substantially.

  As an adhesive resin that can be used for the adhesive composition (b), a conventionally known resin can be selected and used. For example, a thermosetting resin, a pressure-sensitive adhesive resin, or the like can be used.

  Among these, as the adhesive resin, when the thermally expandable adhesive tape of the present invention is used, the adhesive resin can be temporarily fixed to the adherend, and the pressure-sensitive adhesiveness is improved in improving workability during the assembly of the members. It is more preferable to use a resin. As the pressure-sensitive adhesive resin, for example, an acrylic pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a polyurethane pressure-sensitive adhesive, a polyester pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, and the like can be used.

  As said adhesive composition (b), what contains a hardening | curing agent, a hardening accelerator, etc. other than what was mentioned above as needed can be used.

  As the adhesive composition (b), in addition to those described above, a coupling agent, a tackifier, an antifoaming agent, a pigment, an antioxidant, a core-shell type reinforcing agent, a thixotropic agent, You may use what contains a heat conductive filler, an insulating filler, etc.

  The thermally expandable adhesive tape of the present invention includes, for example, the step [1] of forming the adhesive layer (A) by applying the adhesive composition (a) to a release liner and drying it, and the step [1] Separately, the step [2] of forming the adhesive layer (B) by applying the adhesive composition (b) to a release liner and drying, etc., and the one side of the adhesive layer (A) It can be manufactured by transferring the adhesive layer (B) and performing a step [3] of pressing and bonding them.

  A part of the adhesive layer (A) may be cured in the process of producing the thermally expandable adhesive tape, but it is preferable that the adhesive layer (A) is not substantially expanded or cured. A part of the adhesive layer (B) may also be cured in the process of producing the thermally expandable adhesive tape, but it is preferable that the adhesive layer (B) is not substantially cured.

  Moreover, as a thermally expansible adhesive tape of this invention, what has the layer (Z) which consists of a resin film layer or a metal between the said adhesive bond layer (A) and an adhesive bond layer (B) as needed. Can be used. Since such a heat-expandable adhesive tape has good rigidity, it is excellent in sticking workability.

  Examples of the layer (Z) include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamide resins such as polycarbonate, polyarylate, polyurethane, polyamide, and polyetheramide, polyimide, polyetherimide, Polyimide resins such as polyamideimide, polysulfone resins such as polysulfone and polyethersulfone, polyetherketone resins such as polyetherketone and polyetheretherketone, films of organic resins such as polyphenylene sulfide and modified polyphenylene oxide, cellulose fibers Woven materials including organic fibers such as polyester fiber, aramid fiber, and liquid crystal polymer fiber, or inorganic fibers such as glass fiber, metal fiber, and carbon fiber Or nonwoven substrate, a glass plate, a film of an inorganic material such as a metal foil, sheet or plate, and the like laminates thereof. A composite such as glass fiber reinforced plastic (GFRP) can also be used. For example, a woven fabric substrate or a nonwoven fabric substrate containing glass fibers, a glass fiber composite, a glass substrate containing a glass plate, a polyamide resin film, or a polyimide resin film can be used as the substrate. The adhesion between the base material and the adhesive layer can be improved by subjecting the base material to corona treatment or providing a primer layer. Moreover, as the layer (Z), a substrate having a communication port can also be used. As the base material having the communication port, various conventional base materials described above can be used, for example, a paper, a nonwoven fabric, a porous film including the plastic film, a metal mesh, a punching film, or the like. Can do. The communication port means one or more openings that are spatially continuous and connect the first surface and the second surface of the substrate.

  As the layer (Z), it is preferable to use a layer having a thickness of 1 μm to 200 μm, and it is more preferable to use a layer having a thickness of 12 μm to 50 μm.

  In the thermally expandable adhesive tape having the layer (Z), for example, the step [1] of forming the adhesive layer (A) by applying the adhesive composition (a) to a release liner and drying it [1] Separately from [1], the step of forming the adhesive layer (B) by applying the adhesive (b) to a release liner and drying, etc. [2], on one side of the layer (A), the layer (Z) can be manufactured by passing through the step [4] and the step [5] of transferring the adhesive layer (B) onto the surface composed of the layer (Z) and press-bonding them. .

  The thermally expandable adhesive tape of the present invention can be expanded by giving a stimulus to the adhesive layer (A) or the entire thermally expandable adhesive tape. Examples of the stimulus include heat and light as described above. Examples of the method for giving the stimulus include methods such as heating and light irradiation, and it is preferable to employ a heating method.

  The heating temperature is preferably a temperature corresponding to, for example, a temperature at which the expansion agent expands (expansion start temperature), specifically, preferably 80 ° C. to 300 ° C., and 90 ° C. to 200 ° C. It is more preferable that deterioration of the adherend due to the influence of heat or the like can be suppressed and unintentional expansion can be prevented during storage of the thermally expandable adhesive tape of the present invention.

  The adhesive tape of the present invention preferably expands in the thickness direction after the stimulus such as heating is given. On the other hand, it is preferable that the adhesive tape of the present invention does not substantially expand in the flow direction or the width direction after the stimulation such as heating is given.

  As a method for fixing two or more adherends using the thermally expandable adhesive tape of the present invention, for example, one adherend and one of the adhesive layers constituting the adhesive tape are previously used. The pasted material is placed at a predetermined position, and the adhesive layer (A) is stimulated and expanded, thereby causing the other surface of the adhesive layer constituting the adhesive tape to be adhered to the other surface. A method of bringing the body into contact with each other and bonding them can be mentioned. At that time, the stimulus may be applied to the adhesive layer (A) constituting the thermally expandable adhesive tape, or may be applied to the entire thermally expandable adhesive tape. Note that the adhesive layer to be applied to the adherend may be either the adhesive layer (A) or the adhesive layer (B) in advance, but when it is necessary to temporarily fix the adhesive layer with sufficient adhesive force. The adhesive layer (B) and the adherend are preferably pasted in advance.

  As described above, the thermally expandable adhesive tape of the present invention is suitably used when manufacturing an article having a configuration in which the adherend (D1) and the adherend (D2) are fixed. be able to.

  Examples of the article include a small motor mounted on a movable part of an automobile. The motor is usually composed of an exterior member (cylindrical member) and its lid-like member (FIG. 1). As the motor, specifically, a metal cylindrical member and a resin lid-shaped member having a shape corresponding to the cylindrical member are fixed in a fitted state.

  The ratio of the linear expansion coefficient of the cylindrical member and the linear expansion coefficient of the lid member [linear expansion coefficient of the cylindrical member (d2) / linear expansion coefficient of the lid member (d1)] is as described above. 2 to 1000.

  As a method for manufacturing the article, for example, the step of applying the thermally expandable adhesive tape to one of the adherends (D1) and (D2), the adherends (D1) and (D2) are fitted. It can be manufactured by a step of combining, a step of directly expanding the heat-expandable adhesive tape, or a step of heating and expanding through the adherend (D1) or the adherend (D2).

  For example, when the heat-expandable adhesive tape is applied in advance to a lid-like member that can be used as the adherend (D2), the heat-expandable adhesive tape may be applied to the entire outer periphery of the lid-like member. , It may be attached to a part thereof. Further, when a portion (recessed portion) for applying a thermally expandable adhesive tape is provided on a part of the outer peripheral portion of the lid-like member, the thermally expandable adhesive tape is cut into the shape of the recessed portion, Affixing to the recess is preferable because the step of fitting the lid member and the cylindrical member can be performed efficiently. It is preferable that the said recessed part is a recessed part of the depth corresponding to the thickness of the adhesive tape before thermal expansion.

  Moreover, as a process of fitting the adherends (D1) and (D2), for example, in the case of manufacturing the motor, the above is a lid shape having a shape corresponding to the shape of the cylindrical member and its opening. The process of combining with a member is mentioned. At that time, the thermally expandable adhesive tape of the present invention is affixed to the cylindrical member or the lid member, but a thermally expandable adhesive tape having a thickness that does not impair the workability of the fitting process is selected. It is preferable to do.

  Further, in the step of directly heating the heat-expandable adhesive tape or heating and expanding the adherend (D1) or the adherend (D2), the heating temperature may be 80 ° C to 300 ° C. Preferably, it is 90 to 200 ° C.

  As the heating method, for example, the article is put into a heating device such as a dryer or a heating furnace and the whole article is heated, or a heat source is applied to the adhesive layer (A), the adhesive tape, or the adherend. The method of heating an adhesive bond layer (A) by making it contact or approach is mentioned.

  Examples of the heat source include a halogen lamp, a laser irradiation device, an electromagnetic induction heating device, a hot stamp, a hot plate, and a soldering iron. A halogen lamp, a hot stamp, and a hot plate can be used. The heating method can be selected depending on the size of the article.

  Further, as the article, when the adherends (D1) and (D2) are fitted in advance and a gap is formed between them, the thermally expandable adhesive tape of the present invention is put in the gap. It can also be produced by inserting and then heating and expanding the thermally expandable adhesive tape with the same heating method and heating temperature as described above and bonding them together.

  Examples of the articles obtained by the above method include motors mounted on automobiles, electronic devices, home appliances, electric tools, and the like.

(Preparation Example 1)
<Preparation of adhesive composition (a)>
Epiklone N-680 (a cresol novolac type epoxy resin solution manufactured by DIC Corporation, epoxy equivalent 215 g / eq, 75% by mass of non-volatile content) 21.4 parts by mass, “JER YL-7862” (Mitsubishi Chemical Corporation bisphenol) After mixing 48 parts by mass of an A-type epoxy resin solution, epoxy equivalent 3748 g / eq, nonvolatile content 50% by mass), 30.6 parts by mass of methyl ethyl ketone is mixed to obtain an epoxy resin composition having a nonvolatile content of 40% by mass (1 )

  Next, with respect to 100 parts by mass of the epoxy resin composition (1), Expandel 051-40 (manufactured by Nippon Philite Co., Ltd., thermally expandable microcapsule, initial particle size 12 μm, expansion start temperature 110 ° C., Mixing 3.2 parts by mass with a volume expansion coefficient at 130 ° C. of 7 times and 0.4 parts by mass of Curazole 2MAOK-PW (manufactured by Shikoku Kasei Co., Ltd., imidazole curing accelerator) as a curing agent, 10 minutes The adhesive composition (a) was obtained by stirring.

(Preparation Example 2)
<Preparation of adhesive composition (b)>
Using a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel and a nitrogen gas inlet, 90.0 parts by mass of 2-ethylhexyl acrylate, 10.0 parts by mass of acrylic acid, and 2,2 as a polymerization initiator -0.03 part by mass of azobisisonitrile was dissolved in a mixed solvent consisting of 63 parts by mass of ethyl acetate and 100 parts by mass of acetone.

  Next, after the monomer was polymerized by maintaining the inside of the reaction vessel at 65 ° C. for 6 hours, 0.2 part by mass of 2,2-azobisisobutylnitrile and 45 parts by mass of ethyl acetate were added, Furthermore, by carrying out polymerization for 6 hours, an acrylic copolymer solution having a weight average molecular weight of 900,000 (polystyrene conversion) was obtained. Ethyl acetate was added to this acrylic copolymer solution to adjust the nonvolatile content to obtain an acrylic copolymer solution having a nonvolatile content of 30% by mass.

  To the acrylic copolymer solution, 18 parts by mass of an epoxy-based crosslinking agent (“E-05X” manufactured by Soken Chemical Co., Ltd., solid content: 0.5% by mass) is added to 100 parts by mass of the acrylic copolymer. By stirring for a minute, an adhesive composition (b) was obtained.

Example 1
<Production of thermally expandable adhesive tape>
Using a rod-shaped metal applicator, the thickness after drying of the adhesive composition (a) is 50 μm on the surface of a release film in which one side of a 75 μm-thick polyethylene terephthalate film is peeled off with a silicone compound. The adhesive layer (A) was produced by coating for 3 minutes and drying with a dryer set at 80 ° C. for 3 minutes.

  Next, the adhesive composition (b) is dried on the surface of a release film having one surface of a 75 μm-thick polyethylene terephthalate film peel-treated with a silicone compound using a rod-shaped metal applicator. The adhesive layer (B) was prepared by coating for a thickness of 100 μm and drying for 10 minutes with a dryer set at 75 ° C.

  By sticking the adhesive layer (B) to the adhesive layer (A) obtained above and using a 2 kg hand roller, the adhesive layer (A) of the adhesive layer (A) is moved back and forth once. A heat-expandable adhesive tape 3 ′ having an adhesive layer (B) laminated on one side was obtained.

  <Production of articles>

  As an article, an exterior member (cylindrical member) constituting a small motor mounted on a movable part of an automobile and its lid-like member were assumed. As the adherend fixed in the fitted state, a metal cylindrical member 1 described later and a resin lid member 2 described later having a shape corresponding to the metal cylindrical member 1 were used.

  First, the thermally expandable adhesive tape 3 ′ is cut into a size of 7 mm × 7 mm, and the adhesive layer on the side corresponding to the adhesive layer (B) is the smallest part (diameter of the outer diameter of the lid-like member 2. 29.5 mm outer peripheral part) was previously bonded.

  Next, the lid-like member 2 is inserted into the tubular member 1, and the tubular member 1 and the outer shape of the lid-like member 2 (the outer peripheral portion having a diameter of 30 mm) are fitted (the tubular member 1). The opening and the lid-like member 2 were combined with each other).

  Next, they are allowed to stand in a heating furnace set at 130 ° C. for 1 hour, and the adhesive layer corresponding to the adhesive layer (A) is expanded so that the adherends adhere to each other. Got.

  In the state in which the tubular member 1 and the lid-like member 2 are fitted, the outer peripheral portion of the lid-like member having a maximum outer diameter of 30 mm is fitted to the tubular member 1 (the tubular member 1 And the lid-like member 2 is assembled), and a gap of 0.25 mm is provided between the outer peripheral portion of the lid-like member 2 having an outer diameter of 29.5 mm and the cylindrical member 1. .

  As described above, the heat-expandable adhesive tape 3 ′ was attached to the minimum part of the outer diameter of the lid-like member 2. Therefore, in a state where the lid-like member 2 is inserted and fitted into the cylindrical member 1, the tubular member 1 and the lid-like member 2 are not bonded by the thermally expandable adhesive tape 3 '.

  Thereafter, the fitting is allowed to stand in a dryer set at 130 ° C. for 1 hour, and the adhesive layer corresponding to the adhesive layer (A) is expanded, whereby the cylindrical member 1 and the lid are expanded. The shaped member 2 was adhered by a thermally expandable adhesive tape 3.

<Metallic tubular member 1>
A cylindrical member made of stainless steel having a linear expansion coefficient of 10.4 × 10 ⁻⁶ measured according to JIS Z 2285: 2003 and having an opening on only one side having an outer diameter of 33 mm and an inner diameter of 30 mm. It was used.

<Resin lid member 2>
A lid-like member made of 6,6-nylon having a linear expansion coefficient of 100 × 10 ⁻⁶ measured according to JIS K 7197: 2012, with an outer diameter of 30 mm at the maximum and 29.5 mm at the minimum, FIG. The lid-shaped member having the shape shown in FIG.

<Linear expansion coefficient ratio>
6,6-nylon linear expansion coefficient (d2) / stainless steel linear expansion coefficient (d1) = 9.6

(Example 2)
<Production of thermally expandable adhesive tape>
Using a rod-shaped metal applicator, the thickness after drying of the adhesive composition (a) is 50 μm on the surface of a release film in which one side of a 75 μm-thick polyethylene terephthalate film is peeled off with a silicone compound. The adhesive layer (A-1) was produced by coating for 10 minutes and drying with a dryer set to 75 ° C. for 10 minutes.

  Next, a film made of polyethylene terephthalate having a thickness of 50 μm was bonded to one side of the adhesive layer (A-1).

  Next, the adhesive composition (b) is dried on the surface of a release film having one surface of a 75 μm-thick polyethylene terephthalate film peel-treated with a silicone compound using a rod-shaped metal applicator. The adhesive layer (B-1) was prepared by coating for 3 μm and drying for 3 minutes with a drier set at 80 ° C.

  Next, the adhesive layer (B-1) is attached to a film made of polyethylene terephthalate, and the adhesive layer (A- An adhesive tape in which a polyethylene terephthalate film was laminated on one side of 1) and an adhesive layer (B-1) was laminated on the other side was obtained.

<Production of articles>
The article was prepared by the same method as in Example 1, and the same metal cylindrical member and resin lid member as in Example 1 were used.

(Example 3)
<Resin-covered member>
Instead of the lid member made of 6,6-nylon, a lid member made of polyphenylene sulfide (PPS) having the same shape and having a linear expansion coefficient of 22 × 10 ⁻⁶ measured according to JIS K 7197: 2012 An article was produced in the same manner as in Example 1 except that was used.
Polyphenylene sulfide linear expansion coefficient (d2) / stainless steel linear expansion coefficient (d1) = 2.1

(Comparative Example 1)
<Preparation of adhesive tape>
Using a rod-shaped metal applicator, the thickness after drying of the adhesive composition (b) is 50 μm on the surface of a release film in which one side of a 75 μm-thick polyethylene terephthalate film is peeled with a silicone compound. The adhesive layer (B-1) was produced two sheets by drying for 10 minutes with the drying machine which apply | coated and set to 75 degreeC.

  Next, a film made of polyethylene terephthalate having a thickness of 50 μm was bonded to one side of the adhesive layer (B-1).

  Next, the adhesive layer (B-1) is attached to the film made of polyethylene terephthalate, and the adhesive is reciprocated once by using a 2 kg hand roller. An adhesive tape in which a polyethylene terephthalate film was laminated on one side of the layer (A-1) and an adhesive layer (B-1) was laminated on the other side was obtained.

<Production of articles>
The article was prepared by the same method as in Example 1, and the same metal cylindrical member and resin lid member as in Example 1 were used.

(Comparative Example 2)
Articles were prepared without using an adhesive tape, and the same members as in Example 1 were used.

  [Adhesive tape and method for measuring expansion coefficient of each adhesive layer constituting it]

  The expansion coefficient of the adhesive layer (A) was calculated by the following method.

  The thickness of the adhesive layer (A) constituting the adhesive tape before being left for 1 hour in a 130 ° C. environment (before expansion) was measured using a thickness meter in a 23 ° C. environment.

  The adhesive tape was left in an environment at 130 ° C. for 1 hour.

  The adhesive tape after the standing was taken out in a 23 ° C. environment, and the thickness of the adhesive layer (A ′) formed by immediately expanding the adhesive layer (A) was measured with a thickness meter.

The expansion coefficient was calculated based on the measurement result and the following formula.
[The thickness of the adhesive layer (A) constituting the adhesive tape after standing] [The thickness of the adhesive layer (A ') formed by swelling] / of the adhesive layer (A) constituting the adhesive tape before standing Thickness] × 100
The expansion coefficient of the pressure-sensitive adhesive layer (B) was calculated by the following method.

  The thickness of the adhesive layer (B) constituting the adhesive tape before being left for 1 hour in a 130 ° C. environment (before expansion) was measured with a thickness meter in a 23 ° C. environment.

  The adhesive tape was left in an environment at 130 ° C. for 1 hour.

  The adhesive tape after standing was taken out in an environment of 23 ° C., and the thickness of the adhesive layer (B ′) corresponding to the adhesive layer (B) was immediately measured with a thickness meter.

The expansion coefficient was calculated based on the measurement result and the following formula.
[The thickness of the adhesive layer (B ′) constituting the adhesive tape after being left / the thickness of the adhesive layer (B) constituting the adhesive tape before being left] × 100
The expansion coefficient of the adhesive tape was calculated by the following method.

  The thickness of the adhesive tape before being left for 1 hour in a 130 ° C. environment (before expansion) was measured in a 23 ° C. environment.

  The adhesive tape was left in an environment at 130 ° C. for 1 hour.

  The adhesive tape after standing was taken out in an environment of 23 ° C., and the thickness was immediately measured with a thickness meter.

The expansion coefficient was calculated based on the measurement result and the following formula.
[Thickness of the adhesive tape after being left / thickness of the adhesive tape before being left] × 100

[After thermal cycle test-adhesive strength measurement]
The article 4 obtained above was allowed to stand in an environment of −40 ° C. for 30 minutes and then in an environment of 85 ° C. for 30 minutes, and this was repeated 1000 times. After the repeated test, the lid-like member 2 constituting the article 4 is fixed using a tensile tester, the tubular member 1 is pulled in the vertical direction at 10 mm / min, and the lid-like member 2 and the tubular shape are The strength when the member 1 was separated was measured.

[After thermal cycle test-Vibration evaluation]
The article 4 obtained above was allowed to stand in an environment of −40 ° C. for 30 minutes and then in an environment of 85 ° C. for 30 minutes, and this was repeated 1000 times. Thereafter, the article 4 was shaken by hand, and whether or not there was rattling was evaluated according to the following criteria.
○: No rattling sound due to vibration.
X: A rattling sound due to vibration was heard.

  In the article obtained in the example, since the tubular member and the lid-like member are bonded by the thermally expanded adhesive tape, as shown in FIG. 2, the shrinkage of the lid-like member after the thermal cycle test is suppressed, or Even when the lid-like member 2 contracts, it is possible to effectively suppress the rattling noise caused by the dismantling of the article and the vibration of the member.

DESCRIPTION OF SYMBOLS 1 Metal cylindrical member 2 Resin lid-shaped member 2 'Shrinked resin lid-shaped member 3' Thermal expansion adhesive tape before thermal expansion 3 Adhesive tape 4 after thermal expansion

Claims (7)

A thermally expandable adhesive tape used when the adherend (D1) and the adherend (D2) are fixed in a fitted state, and the linear expansion coefficient (d1) of the adherend (D1) and The linear expansion coefficient (d2) of the adherend (D2) is in the range of [linear expansion coefficient (d2) / linear expansion coefficient (d1)] = 2 to 1000. tape. The heat-expandable adhesive tape according to claim 1, wherein one of the adherend (D1) and the adherend (D2) is a metal member, and the other is a resin member. Either one of the adherend (D1) and the adherend (D2) is a cylindrical member, and the other is a lid-like member, and the lid-like member is fitted into the opening of the cylindrical member. The thermally expandable adhesive tape according to claim 1 or 2. A heat-expandable adhesive tape having an adhesive layer (B) on one side of the adhesive layer (A) directly or via another layer, wherein the heat-expandable adhesive tape is placed in an environment at 130 ° C. Expansion rate in the thickness direction of the adhesive layer (A) after being left for a time [thickness of the adhesive layer (A) after being left / thickness of the adhesive layer (A) before being left] × 100 is 200% or more, and the expansion rate in the thickness direction of the adhesive layer (B) [the thickness of the adhesive layer (B) after being left / the adhesive layer (B) before being left) The thickness] × 100 is 120% or less. The heat-expandable adhesive tape according to claim 1. The thermal expansion according to claim 4, wherein the adhesive layer (A) is a layer that can expand in the thickness direction by stimulation, and is an adhesive layer that is applied in advance to an adherend before the expansion. Adhesive tape. The thermal expansion property according to claim 4 or 5, wherein the adhesive layer (A) has a thickness of 1 µm or more, and the adhesive layer (B) has a thickness of 5 µm or more. Adhesive tape. An article having a configuration in which an adherend (D1) and an adherend (D2) are fitted and fixed by a thermally expandable adhesive tape, the linear expansion coefficient (d1) of the adherend (D1) ) And the linear expansion coefficient (d2) of the adherend (D2) are in the range of [linear expansion coefficient (d2) / linear expansion coefficient (d1)] = 2 to 1000.

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