JP7077735B2 - Adhesive tape, articles, motors and manufacturing methods for articles - Google Patents

Description

The present invention relates to an adhesive tape having a structure in which the volume is expanded by giving a stimulus such as heating.

Since the adhesive tape can be suitably used for fixing two or more adherends, it is widely used in the manufacturing scene of various products such as automobiles and electric devices.

Adhesive tapes can generally be suitably used when fixing one adherend to a flat surface portion, a curved surface portion, or the like of the other adherend, and can be used for various purposes such as automobile members and electrical equipment. Widely used in the manufacturing of various products. On the other hand, as the range of use of the adhesive tape is expected to be further expanded, the adhesive tape is suitable for fixing the other adherend in the voids of one adherend, for example. It is required to be able to be used for. Specifically, as a motor mounted on a hybrid vehicle or the like, a motor having a configuration in which a magnet is embedded in a predetermined position (void) of a core portion (rotor core) is generally known, and the core portion is described. It has been considered to use the adhesive tape when fixing the magnet in the voids of the magnet. As an adhesive tape that can be used in the above-mentioned applications, a thermosetting heat-expandable adhesive tape that expands and adheres by heating is known (Patent Document 1). However, since this adhesive tape needs to be inserted into the gap between the members before the members are fixed to each other by heating and expanding, the initial adhesiveness of the surface of the adhesive tape at room temperature is low or absent. Therefore, even if it is inserted into the gap between the members, it cannot be immediately adhered to the member. Therefore, before the adhesive tape in the previous period is expanded and adhered / fixed, the adhesive tape is displaced from a predetermined position. There was a risk that the adhesive position of the adhesive tape and the member would be misaligned.

Japanese Unexamined Patent Publication No. 2013-023559

The problem to be solved by the present invention is an adhesive tape that can be expanded by a stimulus such as heating, has excellent initial adhesiveness even at room temperature (23 ° C.), and has excellent adhesive strength even after expansion. Is to provide an adhesive tape capable of holding.

The present inventors have an adhesive tape having a pressure-sensitive adhesive layer (B) on one side of the expandable adhesive layer (A), directly or via another layer, and the pressure-sensitive adhesive layer ( It has been found that the above-mentioned problems can be solved by an adhesive tape having a thickness of B) of 1 μm or more and 100 μm or less and an adhesive force of 180 degrees peeling off at room temperature (23 ° C.) of 1 N / 20 mm or more.

Since the adhesive tape of the present invention exhibits initial adhesive force (temporary fixing property) to the member at room temperature (23 ° C) even before expansion, the adhesive tape can be immediately attached to the member after being inserted into the gap. Therefore, the adhesive position is less likely to shift. Further, since excellent adhesive strength can be maintained even after expansion, it can be used for fixing two or more adherends, and the other adherend is fixed in the gap of one adherend. It can be suitably used in applications such as filling the voids of the adherend with the adhesive tape.

It is a conceptual diagram which shows the measuring method of the shear adhesive force of an adhesive tape.

The adhesive tape of the present invention is an adhesive tape having a pressure-sensitive adhesive layer (B) on one side of an expandable adhesive layer (A) containing a thermosetting resin, either directly or via another layer. The pressure-sensitive adhesive layer (B) has a thickness of 1 to 100 μm, and has a 180-degree peeling adhesive strength at room temperature (23 ° C.) of 1 N / 20 mm or more.

The expandable adhesive layer (A) expands due to an external stimulus. Examples of external stimuli include heat, light, and the like, but heat is particularly preferable.
The expandable adhesive layer (A) includes the expansion rate in the thickness direction of the expandable adhesive layer (A) [the thickness of the expandable adhesive layer (A') after heating / the expansion before heating. Thickness of the sex adhesive layer (A)] × 100 is 150% or more. The expansion coefficient is preferably 175% or more, and more preferably 200% to 1000%. In the case of such an adhesive tape, the height (thickness) of the voids of the adherend (C1) or the voids between the adherend (C1) and the adherend (C2) is large. Also, by expanding the adhesive tape, the other adherend can be suitably fixed in the void, or the void can be filled with the adhesive tape. Further, with the adhesive tape, even if the surface of the adherend is a rough surface, the other adherend can be suitably fixed to the rough surface.

The expansion rate is the same as the thickness of the expandable adhesive layer (A) before the leaving (before expansion) when the adhesive tape is left at a temperature of 50 ° C. to 250 ° C. for 30 minutes. It refers to the ratio of the thickness of the expandable adhesive layer (A1) formed by expanding the expandable adhesive layer (A), preferably at a temperature of 60 ° C to 230 ° C, preferably 70 ° C to 200 ° C. The temperature is more preferable.

The thickness of the expandable adhesive layer (A) constituting the adhesive tape is preferably 1 μm or more, more preferably 10 μm to 250 μm, in order to obtain even more excellent adhesive strength. It is more preferably in the range of 15 μm to 150 μm, and particularly preferably in the range of 20 μm to 100 μm.

On the other hand, the thickness of the adhesive layer (A') formed by expanding the expandable adhesive layer (A) is in the range of 20 μm to 2500 μm in order to obtain even more excellent adhesive strength. Is preferable, and the range is more preferably in the range of 40 μm to 1500 μm. Further, the expandable adhesive layer (A') preferably has a porous structure.

Further, as the adhesive tape, it is preferable to use a tape having a thickness of the expandable adhesive layer (A) of 10% or more, preferably 30% or more, with respect to the total thickness of the adhesive tape. It is more preferable to use one. Within the above range, for example, it becomes easy to fix the other adherend in the voids of one adherend, or to fill the voids with the adhesive tape.

As the expandable adhesive layer (A), a layer that can expand by giving a stimulus such as heat or light as described above can be used, and specifically, a layer containing various resins and a leavening agent can be used. Can be used.
The expandable adhesive layer (A) can be formed, for example, by applying an adhesive composition (a) containing the resin, a leavening agent, or the like to a release liner or the like and drying it.

As the adhesive composition (a) that can be used for forming the expandable adhesive layer (A), a composition containing a resin, a swelling agent, a solvent or the like, if necessary, can be used as described above. ..
As the expandable adhesive layer (A), an adhesive composition (a) containing a thermosetting resin or the like, which will be described later, is used.

As the thermosetting resin, for example, one or more thermosetting tree species selected from urethane resin, phenol resin, unsaturated polyester resin, epoxy resin, acrylic resin and the like can be used. Among them, it is preferable to use an epoxy resin and / or an acrylic resin as the thermosetting resin in order to impart good adhesion to the adherend during heat curing, and it is preferable to use an epoxy resin. Is more preferable in ensuring good heat curability.

Specific examples of the epoxy resin include a bisphenol A type epoxy resin, a bisphenol type epoxy resin such as a bisphenol F type epoxy resin, a dicyclopentadiene type epoxy resin such as a dicyclopentadiene-phenol addition reaction type epoxy resin, and a biphenyl type. Epoxy resin, tetramethylbiphenyl type epoxy resin, polyhydroxynaphthalene type epoxy resin, isocyanate-modified epoxy resin, 10- (2,5-dihydroxyphenyl) -9,10-dihydro 9-oxa-10-phosphaphenanthrene-10- Oxide-modified epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, phenol aralkyl type epoxy resin, naphthol novolac type epoxy resin, naphthol aralkyl type epoxy resin, naphthol -Pharmon co-shrink novolak type epoxy resin, naphthol-cresol co-shrink novolak type epoxy resin, aromatic hydrocarbon formaldehyde resin modified phenol resin type epoxy resin, biphenyl-modified novolak type epoxy resin and the like can be used.

The thermosetting resin such as the epoxy resin is preferably contained in an amount of 10% by mass to 99% by mass with respect to the entire adhesive layer (A).
Further, as the expandable adhesive layer (A), it is preferable to use one containing a curing agent capable of reacting with the thermosetting resin.
As the curing agent, for example, when an epoxy resin is used as the thermosetting resin, it is preferable to use one having a functional group capable of reacting with the epoxy group.

The curing temperature of the thermosetting material is preferably equal to or higher than the expansion temperature of the leavening agent described later, and the curing time is preferably equal to or longer than the expansion time. As a result, the leavening agent can be sufficiently expanded in the thermosetting material softened by heating, and the sheet thickness after expansion can be made uniform.

Examples of the curing agent include amine-based compounds, amide-based compounds, acid anhydride-based compounds, and phenol-based compounds. For example, as the amine compound, diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole derivative, BF3-amine complex, guanidine derivative and the like can be used.

Examples of the amide compound include a polyamide resin synthesized from a dimer of dicyandiamide and linolenic acid and ethylenediamine, and examples of the acid anhydride compound include phthalic anhydride, trimellitic anhydride and anhydrous. Examples thereof include pyromellitic acid, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnagic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic acid and the like, and examples of the phenolic compound include phenol novolac. Resin, cresol novolak resin, aromatic hydrocarbon formaldehyde resin modified phenol resin, dicyclopentadienephenol addition type resin, phenol aralkyl resin (Zyroc resin), naphthol aralkyl resin, trimethylolmethane resin, tetraphenylol ethane resin, naphthol novolak resin , Naftor-phenol co-condensed novolak resin, naphthol-cresol co-condensed novolak resin, biphenyl-modified phenol resin (polyhydric phenol compound in which phenol nuclei are linked by bismethylene groups), biphenyl-modified naphthol resin (phenol nuclei linked by bismethylene groups) Polyvalent naphthol compound), aminotriazine-modified phenolic resin (a compound having a phenol skeleton, a triazine ring and a primary amino group in its molecular structure) and an alkoxy group-containing aromatic ring-modified novolak resin (formaldehyde containing a phenol nucleus and an alkoxy group). Examples thereof include polyhydric phenol compounds such as polyhydric phenol compounds in which rings are linked.

The curing agent is preferably used in the range of 0.1 part by mass to 60 parts by mass, and 0.5 part by mass to 45 parts by mass with respect to 100 parts by mass in total of the heat-curable resin such as the epoxy resin. It is preferable to use it in the range of 1 part by mass to 30 parts by mass, and it is more preferable to use it in the range of 1 part by mass to 30 parts by mass because the heat-curable resin can be sufficiently cured.

Further, as the thermosetting material, a material containing a curing accelerator can be used. As the curing accelerator, a phosphorus compound, an amine compound, an imidazole derivative, or the like can be used. When the curing accelerator is used, the amount used is preferably 0.1 part by mass to 10 parts by mass, and 0.5 part by mass with respect to 100 parts by mass in total of the thermosetting resin such as the epoxy resin. It is more preferably in the range of up to 5 parts by mass.

As the curing agent and curing accelerator, it is preferable to use powdery ones. Since the powdery curing accelerator suppresses the thermosetting reaction at a low temperature as compared with the liquid curing accelerator, the storage stability of the thermosetting material before the thermosetting at room temperature is further improved. Can be improved.

Further, as the expandable adhesive layer (A), even when the expandable adhesive layer (A') composed of the thermosetting material is used in an environment where the temperature change is large, the bonding is performed. A material containing a thermoplastic resin can be used as long as the fixing property of the portion is not impaired.

Examples of the thermoplastic resin include urethane resins such as polyurethane (PU) and thermoplastic polyurethane (TPU); polycarbonate (PC); polyvinyl chloride (PVC) and vinyl chloride such as vinyl chloride-vinyl acetate copolymer resin. Based resin: Acrylic resin such as polyacrylic acid, polymethacrylic acid, methyl polyacrylate, polymethylmethacrylate (PMMA), polyethyl methacrylate; polyethylene terephthalate (PET), polybutylene terephthalate, Polyester resins such as polytrimethylene terephthalate, polyethylene naphthalate, and polybutylene naphthalate; polyamide resins such as nylon (registered trademark); polystyrene (PS), imide-modified polystyrene, acrylonitrile-butadiene. Polystyrene resin such as styrene (ABS) resin, imide-modified ABS resin, styrene / acrylonitrile copolymer (SAN) resin, acrylonitrile / ethylene-propylene-diene / styrene (AES) resin, polyethylene (PE) resin, polypropylene (PP) Olefin-based resins such as resins and cycloolefin resins; Cellulosic resins such as nitrocellulose and cellulose acetate; Silicone-based resins; Thermoplastic resins such as fluororesins, styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, vinyl chloride-based Thermoplastic elastomers such as thermoplastic elastomers, urethane-based thermoplastic elastomers, ester-based thermoplastic elastomers, and amide-based thermoplastic elastomers can be used.

For the above reasons, the thermoplastic resin is preferably used in the range of 1 part by mass to 100 parts by mass with respect to 100 parts by mass of the thermosetting resin.

In addition to the above-mentioned thermosetting materials, for example, fillers, softeners, stabilizers, adhesion promoters, leveling agents, defoaming agents, plasticizers, etc., as long as the effects of the present invention are not impaired. Adhesive-imparting resins, fibers, antioxidants, ultraviolet absorbers, antioxidants, thickeners, colorants such as pigments, and additives such as fillers can be used.
The curing agent and curing accelerator are preferably used before the thermosetting material is thermally cured or before it is formed into a sheet or the like.

As the swelling agent that may be contained in the swellable adhesive layer (A), it is preferable to use a swelling agent layer (A') that can form a porous structure after the swelling, for example, carbonic acid. Inorganic compounds such as ammonium, ammonium hydrogencarbonate, ammonium nitrite, ammonium hydride, azide, alkane fluorides such as trichloromonofluoromethane, azo compounds such as azobisisobutyronitrile, hydrazine compounds such as paratoluenesulfonyl hydrazide, Semicarbazide compounds such as p-toluenesulfonyl semicarbazide, triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole, and N-nitroso compounds such as N, N'-dinitrosoterephthalamide can be used. ..

Further, as the leavening agent, for example, an expandable capsule in which a hydrocarbon solvent is microencapsulated can be used. The above-mentioned leavening agent can be used alone or in combination of two or more.

As the leavening agent, among the above, using an expandable capsule in which a hydrocarbon solvent is microencapsulated is to prevent deterioration of the expandable adhesive layer (A) due to the influence of heat or the like, for example. More preferred.
Further, it is preferable to use a leavening agent that can expand at a temperature around the softening point of the expandable adhesive layer (A) because the adhesive tape can be sufficiently expanded.

Examples of commercially available expandable capsules include Expandel (manufactured by Nippon Phillight Co., Ltd.), Matsumoto Microsphere (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.), Microsphere (manufactured by Kureha Corporation), and the like. As the inflatable capsule, it is preferable to use a capsule having a volume (volume expansion rate) of 8 to 60 times after expansion with respect to the volume of the capsule before expansion.

The amount of the swelling agent used, preferably the amount of the heat-expandable capsule, is 0.3 parts by mass to 30 parts by mass with respect to 100 parts by mass of the solid content of all the components of the heat-expandable adhesive layer (A). The range is preferably in the range of parts, more preferably in the range of 0.5 parts by mass to 25 parts by mass, and further preferably in the range of 1 part by mass to 20 parts by mass. When the amount used is in the above range, it can be sufficiently expanded to fill the voids of the adherend, and even more excellent adhesive strength can be obtained.

Further, as the adhesive tape, a tape having a pressure-sensitive adhesive layer (B) on one side of the expandable adhesive layer (A) is used. The pressure-sensitive adhesive layer (B) may be directly laminated on one surface side of the expandable adhesive layer (A), and may be laminated via another layer such as a so-called core. May be done.

The pressure-sensitive adhesive layer (B) preferably has a thickness of 1 μm or more and 100 μm or less, preferably 2 μm or more and 80 μm or less, and more preferably 3 μm or more and 60 μm or less. By setting the thickness within the above range, for example, even if the surface of the adherend (C1) is rough or uneven, it follows the surface of the adherend and provides good temporary fixing property. This is because the obtained adhesive tape is stimulated to expand the heat-expandable adhesive layer (A), and excellent adhesive strength can be obtained even after the gaps between the adherends are filled and fixed. preferable.

As for the adhesive force of the pressure-sensitive adhesive layer (B), the 180-degree peeling adhesive force according to JIS Z 0237 is 1 N / 20 mm or more at room temperature (23 ° C.), but 1.25 N / 20 mm or more. It is preferably 1.5 N / 20 mm or more, more preferably 1.75 N / 20 mm or more, and even more preferably 2 N / 20 mm or more. By setting the 180-degree peeling adhesive strength within the above range, after the pressure-sensitive adhesive layer (B) surface side of the adhesive tape is attached to the adherend (C1), for example, the adherend (C1) and the adherend are coated. When assembling the adherend (C2), the adhesive tape attached to the adherend (C1) is prevented from being caught by the adherend (C2) and rolled up, or the adhesive tape is not attached at a misaligned position. be able to.

The pressure-sensitive adhesive layer (B) has an expansion rate in the thickness direction of the pressure-sensitive adhesive layer (B) when placed under the same heating conditions as the expandable adhesive layer (A). [Thickness of the pressure-sensitive adhesive layer (B) after being left to stand / Thickness of the pressure-sensitive adhesive layer (B) before being left to stand] × 100 is preferably 120% or less.
The expansion coefficient of the pressure-sensitive adhesive layer (B) is preferably 115% or less, and more preferably 100% to 115%.

The expansion coefficient of the pressure-sensitive adhesive layer (B) is the expansion rate of the pressure-sensitive adhesive layer (B) before being left to stand when it is placed under the same heating conditions as the expandable adhesive layer (A). It refers to the ratio of the thickness of the pressure-sensitive adhesive layer (B') after being left to stand to the thickness. Specifically, the expansion coefficient refers to a value calculated by the following method.
The thickness of the pressure-sensitive adhesive layer (B) constituting the adhesive tape before being left under the same heating conditions as the expandable adhesive layer (A) (before expansion) is measured in an environment of 23 ° C. .. The adhesive tape is left under the same heating conditions as the expandable adhesive layer (A). The adhesive tape after being left to stand is taken out in an environment of 23 ° C., and the thickness of the pressure-sensitive adhesive layer (B') corresponding to the pressure-sensitive adhesive layer (B) is immediately measured. The expansion coefficient is calculated based on the above measurement result and the following formula.
[Thickness of the pressure-sensitive adhesive layer (B') constituting the adhesive tape after being left unattended / Thickness of the pressure-sensitive adhesive layer (B) constituting the adhesive tape before being left unattended] × 100

The adhesive composition (b) used for the pressure-sensitive adhesive layer (B) has excellent adhesive strength at room temperature (23 ° C.) and is excellent even after the adhesive tape is inflated. It is preferable to use one that can develop adhesive strength.

As the adhesive resin that can be used for the adhesive composition (b), a conventionally known resin can be selected and used.
As the adhesive composition (b), for example, an acrylic resin, a rubber resin, a polyurethane resin, a polyester resin, a silicone resin, or the like can be used.

As the acrylic resin, for example, one obtained by polymerizing a monomer containing an alkyl (meth) acrylate can be used, and for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl ( Meta) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-eth-1 ruhexyl ( Meta) One type of acrylate or the like or two or more types can be used in combination. Among them, as the alkyl (meth) acrylate, using an alkyl (meth) acrylate having an alkyl group having 4 to 12 carbon atoms is excellent in followability and adhesion to an adherend having surface irregularities, and is attached. It is more preferable to obtain an adhesive tape having excellent workability.
In addition to the above-mentioned monomers, acrylic nitrile, (meth) acrylic acid, maleic anhydride, acrylamide, itaconic acid, styrene, vinyl acetate and the like can be used as the monomer.

Examples of the rubber-based resin include a styrene-based AB type diblock copolymer such as a styrene-ethylene-butylene copolymer (SEB); a styrene-butadiene-styrene copolymer (SBS), and a hydrogenated additive of SBS (SBS). Styline-ethylene-butylene-styrene copolymer (SEBS)), styrene-isoprene-styrene copolymer (SIS), SIS hydrogenated additive (styrene-ethylene-propylene-styrene copolymer (SEPS)), styrene- A styrene-based ABA-type triblock copolymer such as isobutylene-styrene copolymer (SIBS); a styrene-based ABAB-type tetrablock copolymer such as styrene-butadiene-styrene-butadiene (SBSB); styrene-butadiene-styrene-butadiene -A styrene-based ABAB A-type pentablock copolymer such as styrene (SBSBS); a styrene-based multi-block copolymer having these or more AB repeating units; a styrene-based random copolymer such as styrene-butadiene rubber (SBR), ethylene. A hydrogenated product obtained by hydrogenating a sex double bond; and the like. Commercially available products may be used as the styrene-based thermoplastic elastomer.

As the pressure-sensitive adhesive layer (B), one having adhesiveness at room temperature (23 ° C.) is used. As the pressure-sensitive adhesive layer (B), the shear storage elastic modulus G ₂₃ measured by the dynamic viscoelastic spectrum at 1 Hz and 23 ° C. is in the range of 1.0 × 10 ³ to 5.0 × 10 ⁷ Pa. It is preferable to use the one which is 5.0 × 10 ³ Pa to 4.0 × 10 ⁷ Pa, and it is more preferable to use the one which is 1.0 × 10 ⁴ Pa to 3.0 × 10 ⁷ . It is more preferably in the range of Pa. By setting the above range, it is possible to prevent the adhesive tape from peeling off or being displaced from the adherend, and even if the surface of the adherend has a rough surface or an uneven shape, the adhesive layer (B) Since the adhesion between the surface of the surface and the adherend is further improved, very excellent adhesive strength can be exhibited. The shear storage elastic modulus G ₂₃ is the value of the storage elastic modulus at 23 ° C. as measured by the following measuring method.

The pressure-sensitive adhesive layer (B) adjusted to a thickness of 2 mm by mounting a parallel plate with a diameter of 7.9 mm on a viscoelasticity tester (Ares 2kSTD) manufactured by TA Instruments Japan was attached to the pressure-sensitive adhesive layer (B). It is sandwiched between parallel plates with a compressive load of 40 to 60 g, and measured under the conditions of a frequency of 1 Hz, a temperature range of -60 to 150 ° C., and a heating rate of 2 ° C./min.

As the adhesive composition (b), for example, a resin containing the above-mentioned resin and, if necessary, a tackifier resin, a cross-linking agent, other additives and the like can be used.
The tackifier resin includes, for example, a rosin-based tackifier resin, a polymerized rosin-based tackifier resin, and a polymerized rosin ester-based tackifier resin for the purpose of adjusting the strong adhesiveness of the pressure-sensitive adhesive layer (B). Use rosinphenol-based adhesive-imparting resin, stabilized rosin ester-based adhesive-imparting resin, disproportionate rosin-ester-based adhesive-imparting resin, terpene-based adhesive-imparting resin, terpene-phenol-based adhesive-imparting resin, petroleum resin-based adhesive-imparting resin, etc. Can be done.

Examples of the cross-linking agent include known isocyanate-based cross-linking agents, epoxy-based cross-linking agents, aziridine-based cross-linking agents, and polyvalent metal salt-based cross-linking agents for the purpose of improving the cohesive force of the pressure-sensitive adhesive layer (B). A metal chelate-based cross-linking agent, a keto-hydrazide-based cross-linking agent, an oxazoline-based cross-linking agent, a carbodiimide-based cross-linking agent, a silane-based cross-linking agent, a glycidyl (alkoxy) epoxysilane-based cross-linking agent, and the like can be used.

Examples of the additive include a base (such as aqueous ammonia), an acid, a foaming agent, a plasticizer, a softener, and an antioxidant for adjusting the pH, as long as the desired effect of the present invention is not impaired. Fiber-like, balloon-like, bead-like, metal powder-like fillers made of glass or plastic, colorants such as pigments and dyes, pH adjusters, film forming aids, leveling agents, thickeners, water repellents, erasing agents. Known materials such as foaming agents can be used.

The form of the adhesive composition (b) includes solvent-based, emulsion-type pressure-sensitive adhesives, water-based adhesives such as water-soluble pressure-sensitive adhesives, hot-melt type pressure-sensitive adhesives, UV-curable pressure-sensitive adhesives, and solvent-free EB-curable pressure-sensitive adhesives. The system etc. can be mentioned.

As the adhesive composition (b), one containing a solvent can be used in order to maintain good coating workability and the like. As the solvent, for example, toluene, xylene, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, hexane and the like can be used. When the water-based adhesive composition is used as the adhesive composition (b), water or an aqueous solvent mainly composed of water can be used as the solvent.

The adhesive tape of the present invention has, for example, a step [1] of forming the expandable adhesive layer (A) by applying the adhesive composition (a) to a release liner and drying it. Separately, the step [2] of forming the pressure-sensitive adhesive layer (B) by applying the adhesive composition (b) to the release liner and drying or the like, and the expandable adhesive layer (A). It can be manufactured by transferring the pressure-sensitive adhesive layer (B) to one surface and performing a step [3] of crimping them.

A part of the expandable adhesive layer (A) may be cured in the process of manufacturing the adhesive tape, but it is preferable that the expandable adhesive layer (A) is not substantially expanded or cured. The pressure-sensitive adhesive layer (B) may also be partially cured in the process of producing the adhesive tape, but it is preferable that the pressure-sensitive adhesive layer (B) is not substantially cured.
Further, as the adhesive tape of the present invention, if necessary, a non-woven fabric layer, a resin film layer, or a layer (Z) made of metal is used between the expandable adhesive layer (A) and the pressure-sensitive adhesive layer (B). Can be used. Since such an adhesive tape has good rigidity, it is excellent in sticking workability.

The layer (Z) is, for example, if it is a nonwoven fabric, the material is preferably pulp, rayon, Manila hemp, acrylonitrile, nylon, polyester or the like, and in order to satisfy the tensile strength of the nonwoven fabric, a papermaking step is necessary. You may perform a one-step impregnation treatment in which polyamide is added and coated after drying, or a two-step impregnation treatment using biscous or a thermoplastic resin as a binder. The resin film is a resin film layer formed by using a plastic film such as a polyester film, a polyethylene film, a polypropylene film, a polyvinyl chloride film, or a polyimide film, and the metal layer is a metal layer such as aluminum or copper. Can be mentioned.

As the layer (Z), it is preferable to use a layer having a thickness of 1 μm or more and 200 μm or less, and it is more preferable to use a layer having a thickness of 2 μm or more and 150 μm or less, and it is more preferable to use a layer having a thickness of 3 μm or more and 100 μm or less. It is more preferable to use the one having. By setting the above range, when the pressure-sensitive adhesive layer (B) of the adhesive tape is attached to the adherend, even if the surface of the adherend is rough or uneven, the surface of the adherend is formed. It follows the shape sufficiently and excellent adhesiveness can be obtained.

The adhesive tape having the layer (Z) is, for example, a step [I] of forming the expandable adhesive layer (A) by applying the adhesive composition (a) to a release liner and drying it. Separately from I], the step [II] of forming the pressure-sensitive adhesive layer (B) by applying the adhesive composition (b) to a release liner and drying it, the expandable adhesive layer (A). ), The step of laminating the layer (Z) on one surface [IV], and the step of transferring the pressure-sensitive adhesive layer (B) onto the surface composed of the layer (Z) and crimping them [V]. It can be manufactured by going through.

The adhesive tape of the present invention can be inflated by stimulating the inflatable adhesive layer (A) or the entire adhesive tape. Examples of the stimulus include heat, light, and the like, as described above. Examples of the method of giving a stimulus include a method of heating or light irradiation, and it is preferable to adopt a method of heating.

The heating temperature is preferably, for example, a temperature corresponding to the temperature at which the leavening agent expands (expansion start temperature), specifically, preferably 50 ° C to 250 ° C, and 60 ° C to 230 ° C. It is preferably 70 ° C to 200 ° C, and more preferably 70 ° C to 200 ° C.

It is preferable that the adhesive tape of the present invention expands in the thickness direction after being given a stimulus such as heating. 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 being given a stimulus such as heating.

As a method of fixing two or more adherends by using the adhesive tape of the present invention, for example, one adherend and the pressure-sensitive adhesive layer (B) constituting the adhesive tape are previously attached. The one obtained by pasting is placed in a predetermined position, and at least the expandable adhesive layer (A) is stimulated and expanded to expand the expandable adhesive layer (A) and the like. A method of contacting and adhering to the adherend of the above can be mentioned. At that time, the stimulus may be applied to the expandable adhesive layer (A) constituting the adhesive tape, or may be applied to the entire adhesive tape.

The adhesive tape of the present invention is, for example, a portion (c1-1) constituting the adherend (C1) and another site (c1-2) or another adherend (c1-2) constituting the adherend (C1). It can be suitably used for manufacturing an article having a structure bonded to C2).

The article has a step [1] of preliminarily adhering the pressure-sensitive adhesive layer (B) constituting the adhesive tape and a portion (c1-1) constituting the adherend (C1), and at least the above. The expanded adhesive layer (A) is expanded by stimulating and expanding the expandable adhesive layer (A), and the site (c1-2) or the adherend constituting the adherend (C1). It can be manufactured by going through the step [2] of adhering to (C2).

Examples of the article include a motor mounted on a hybrid vehicle or the like. Specifically, the motor has a gap in which a core member constituting the motor has a pressure-sensitive adhesive layer (B) constituting the adhesive tape and a part of a component such as a magnet bonded in advance. It can be produced by stimulating and expanding at least the expandable adhesive layer (A) after placing it on the floor.

Further, the adhesive tape can be used for the purpose of filling the voids of the adherend. For example, after the adhesive tape is placed in the voids of the adherend, at least the expandable adhesive layer is used. By stimulating and expanding (A), it can also be used when forming a structure in which two or more points in the void are adhered by the adhesive tape.

(Preparation Example 1)
<Preparation of adhesive composition (a-1)>
Epoxy resin 1 (epoxy equivalent 403 g / eq., Liquid (25 ° C.), viscosity 1.4 million mPa · s (25 ° C.)) in 7.0 parts by mass, epoxy resin 2 (epoxy equivalent 162 g / eq., Solid (25 ° C.)) ), Melt viscosity 0.2 dPa · s at 150 ° C., softening point 25 ° C. by 28 parts by mass, epoxy resin 3 (epoxy equivalent 8,000 g / eq., Solid (25 ° C.), softening point 200 ° C. or higher) methyl ethyl ketone solution (Solid content 30% by mass) 216.7 parts by mass, curing agent (2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine isocyanuric acid adduct) 2.0 A thermosetting adhesive composition (a-1) was prepared by mixing parts by mass.

(Preparation Example 2)
Except for changing the epoxy resin 1 from 7 parts by mass to 2 parts by mass and using 5 parts by mass of epoxy resin 4 (epoxy equivalent 130 g / eq., Liquid (25 ° C.), viscosity 300 mPa · s (25 ° C.)). , A thermosetting adhesive composition (a-2) was obtained in the same manner as in Preparation Example 1.

(Preparation Example 3)
<Adhesive composition (b-1) adjustment>
In a reaction vessel equipped with a stirrer, a reflux cooler, a thermometer, a dropping funnel and a nitrogen gas inlet, 80 parts by mass of butyl acrylate, 15 parts by mass of acrylic acid, 5 parts by mass of hydroxyethyl acrylate, and 2,2'as a polymerization initiator. -Acrylate-based copolymer (S-1) solution having a weight average molecular weight of 1 million was obtained by dissolving 0.1 part by mass of azobisisobutylnitrile in 100 parts by mass of ethyl acetate and polymerizing at 70 ° C. for 10 hours. rice field.

Next, in the acrylic copolymer (S-1) solution, an epoxy-based cross-linking agent (“E-05X” manufactured by Soken Kagaku Co., Ltd., solid content 0.5% by mass) with respect to 100 parts by mass of the acrylic copolymer). Was added in an amount of 10 parts by mass, ethyl acetate was added, and the mixture was stirred for 20 minutes to obtain a pressure-sensitive adhesive composition (b-1) having a non-volatile content of 30% by mass.

(Preparation Example 4)
<Adhesive composition (b-2) adjustment>
44.9 parts by mass of butyl acrylate, 50 parts by mass of 2-ethylhexyl acrylate, 2 parts by mass of acrylic acid, 3 parts by mass of vinyl acetate in a reaction vessel equipped with a stirrer, a reflux cooler, a thermometer, a dropping funnel and a nitrogen gas inlet. , 4-Hydroxybutyl acrylate 0.1 part by mass and 2,2'-azobisisobutylnitrile 0.1 part by mass as a polymerization initiator are dissolved in 100 parts by mass of ethyl acetate and polymerized at 70 ° C. for 10 hours. , An acrylic copolymer (T-1) solution having a weight average molecular weight of 800,000 was obtained.

Next, to 100 parts by mass of the acrylic copolymer (T-1), 30 parts by mass of the polymerized rosin ester-based tackifier resin D-135 (manufactured by Arakawa Chemical Industry Co., Ltd.) was added, and ethyl acetate was added. By stirring for 20 minutes, a pressure-sensitive adhesive composition (b-2) having a non-volatile content of 45% by mass was obtained.

(Example 1)
In the thermosetting adhesive composition (a-1) obtained in Preparation Example 1, as a swelling agent, a heat-expandable microcapsule having an expansion start temperature of 108 to 113 ° C., a maximum expansion temperature of 142 to 151 ° C., and a particle size of 9 to 15 μm. 15 parts by mass with respect to 100 parts by mass of the solid content of the thermosetting resin contained in the thermosetting adhesive composition (a-1), and the mixture is stirred for 10 minutes using a dispersion stirrer to expand the thermosetting. A sex adhesive composition (X-1) was obtained.

Next, the thermosetting expandable adhesive composition (X-1) was applied to a rod-shaped metal on the surface of a release liner (one side of a polyethylene terephthalate film having a thickness of 50 μm was peeled off with a silicone compound). Using an applicator, the coating was applied so that the thickness after drying was 50 μm.
Next, the coated material was put into a dryer at 85 ° C. for 5 minutes and dried to obtain a sheet-shaped thermosetting expandable adhesive layer (A-1) having a thickness of 50 μm.

Next, the pressure-sensitive adhesive composition (b-1) was applied to the surface of a release liner (one side of a 50 μm-thick polyethylene terephthalate film peeled with a silicone compound) using a rod-shaped metal applicator. The pressure-sensitive adhesive layer (B-1) was prepared by coating the film so that the thickness after drying was 10 μm and drying the film in a dryer set at 85 ° C. for 5 minutes.
The pressure-sensitive adhesive layer (B-1) is attached to the thermosetting expandable adhesive layer (A-1) obtained above, and the upper surface of the attached object is reciprocated once using a 2 kg hand roller. As a result, an adhesive tape in which the pressure-sensitive adhesive layer (B-1) was laminated on one side of the thermosetting expandable adhesive layer (A-1) was obtained.

(Example 2)
An adhesive tape was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (B-1) was coated so that the thickness after drying was 50 μm.

(Example 3)
The thermosetting expandable adhesive layer (A-1) obtained in Example 1 was attached to a polyethylene terephthalate film having a thickness of 12 μm, and the surface of the attached material was reciprocated once using a 2 kg hand roller. An adhesive tape in which a polyethylene terephthalate film was laminated on one side of the thermosetting expandable adhesive layer (A-1) was obtained. Next, the pressure-sensitive adhesive layer (B-1) obtained by the same method as in Example 1 was laminated on one side of the thermosetting expandable adhesive layer (A-1) with a polyethylene terephthalate film. By using a 2 kg hand roller on the polyethylene terephthalate side and reciprocating the surface of the patch once, one surface of the polyethylene terephthalate has a heat-curable heat-expandable adhesive layer (A-1) and the other surface. An adhesive tape having a pressure-sensitive adhesive layer (B-1) laminated on the side was obtained.

(Example 4)
Other than obtaining the pressure-sensitive adhesive layer (B-2) by using the pressure-sensitive adhesive composition (b-2) obtained in Preparation Example 4 instead of the pressure-sensitive adhesive layer (B-1). Obtained an adhesive tape in the same manner as in Example 1.

(Example 5)
Instead of the thermosetting expandable adhesive layer (A-1), the thermosetting adhesive composition (a-2) obtained in Preparation Example 2 is used to use the thermosetting expandable adhesive layer (A-). An adhesive tape was obtained in the same manner as in Example 1 except that 2) was obtained.

(Comparative Example 1)
An adhesive tape was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive layer (B-1) was coated so that the thickness after drying was 200 μm.
(Comparative Example 2)
An adhesive tape made of a thermosetting expandable adhesive layer (A-1) was obtained in the same manner as in Example 1.

[Measurement method of expansion coefficient]
The thickness of the thermosetting expandable adhesive layer (A-1) and the pressure-sensitive adhesive layer (B-1) constituting the adhesive tapes produced in Examples 1 to 3 and Comparative Examples 1 and 2 is measured by a thickness gauge. Was measured using. Next, the adhesive tape was expanded by leaving it in an environment of 130 ° C. for 10 minutes, and the thickness of the expanded adhesive tape was measured using a thickness gauge.

The expansion rate is the above-mentioned before the thermosetting expandable adhesive layer (A-1) and the pressure-sensitive adhesive layer (B-1) constituting the adhesive tape are left in an environment of 130 ° C. for 10 minutes. The ratio of the adhesive tape after being left to the thickness of the thermosetting expandable adhesive layer (A-1) and the pressure-sensitive adhesive layer (B-1) was calculated according to the following formula.
[Thickness of the thermosetting expandable adhesive layer (A-1) after being left unattended / Thickness of the thermosetting expandable adhesive layer (A-1) before being left unattended] × 100
[Thickness of the pressure-sensitive adhesive layer (B-1) after being left unattended / Thickness of the pressure-sensitive adhesive layer (B-1) before being left unattended] × 100

[Measurement method of initial adhesive strength]
The 180 degree peeling adhesive strength was measured according to JIS Z 0237. The release liner on the surface of the adhesive tape prepared in Examples 1 to 3 and Comparative Examples 1 and 2 on the expandable adhesive layer (A) side was peeled off and lined with a polyethylene terephthalate film having a thickness of 25 μm. At this time, in order to prevent the adhesive tape from falling off from the polyethylene terephthalate, the adhesive tape and the polyethylene terephthalate were bonded and pressure-bonded at 60 ° C. for 1 minute with a load of 1 kN.

The backed adhesive tape is sufficiently allowed to cool at 23 ° C., cut into a width of 20 mm, and then the release liner on the pressure-sensitive adhesive layer (B) side surface of the adhesive tape is peeled off to remove the pressure-sensitive adhesive layer. (B) was attached to the degreased and smooth surface of the SUS plate, and the test piece was reciprocated once with a 2 kg roller. In Comparative Example 2, the release liner on the other surface of the expandable adhesive layer (A) was peeled off, attached to a degreased smooth surface of a SUS plate, and reciprocated with a 2 kg roller as a test piece. After leaving the test piece in an environment of 23 ° C. for 1 hour, a Tensilon tensile tester [manufactured by A & D Co., Ltd., model: RTM-100] was used to apply an adhesive tape constituting the test piece. The adhesive force when peeled from the SUS plate in the 180 degree direction at a speed of 300 mm / min was measured.

[Attachability to members]
The adhesive tapes prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were cut into a rectangular shape having a short side of 25.12 mm and a long side of 30 mm in an environment of 23 ° C. Then, the release liner on the pressure-sensitive adhesive layer (B) side surface of the cut adhesive tape was peeled off in an environment of 23 ° C., and the long side was a cylinder on a SUS degreased cylinder having a diameter of 8 mm and a length of 30 mm. The adhesive tape was attached so as to be perpendicular to the cylinder, and then the adhesive tape was wrapped around the cylinder. For the adhesive tape prepared in Comparative Example 2, the release liner on one surface of the expandable adhesive layer (A) was peeled off and wrapped around a cylinder. At this time, those in which no floating or peeling occurred from the cylinder were evaluated as [◯], and those in which floating or peeling occurred from the cylinder were evaluated as [×].

[Method for measuring the shear storage elastic modulus G23 of the pressure-sensitive adhesive layer (B) at ₂₃ ° C.]
A parallel plate with a diameter of 7.9 mm was attached to a viscoelasticity tester (Ares 2kSTD) manufactured by TA Instruments Japan, and the pressure-sensitive adhesive layer (B-1) and (B) prepared in the examples were prepared. -2) was adjusted to a thickness of 2 mm, sandwiched between the parallel plates with a compressive load of 40 to 60 g, and measured under the conditions of a frequency of 1 Hz, a temperature range of −60 to 150 ° C., and a heating rate of 2 ° C./min.

[Measurement method of shear adhesive strength]
Two aluminum plates with a smooth surface of 15 mm in width × 70 mm in length × 0.5 mm in thickness were degreased and applied to the end of the upper surface (C1-1) of one of the aluminum plates (C1) as shown in FIG. , Two spacers with a width of 5 mm were arranged in parallel with a gap of 12 mm and bonded. The spacer used was prepared so that the total thickness of the adhesive tape used for adhesion with the spacer was 50 μm thicker than the total thickness of the adhesive tape.
Next, an adhesive tape cut to a size of 10 mm × 10 mm on the upper surface (C1-1) side of the aluminum plate (C1) and between the two spacers is pressure-sensitively bonded to the adhesive tape. The release film on the agent layer (B) side was peeled off and attached, and pressure-bonded using a 2 kg hand roller.

Next, the release film on the adhesive layer (A) side of the adhesive tape is peeled off, and another aluminum plate (C2) having a smooth surface that has been degreased on the upper surface of the adhesive layer (A) of the adhesive tape. (Width 15 mm × length 70 mm × thickness 0.5 mm) were placed and fixed with a clip. The fixed product was heated at 130 ° C. for 30 minutes and then left to cool in an environment of 23 ° C. for 30 minutes. Next, the one from which the clip was removed was used as a test piece, and the ends of the two aluminum plates were chucked, respectively, and 180 degrees using a Tensilon tensile tester [manufactured by A & D Co., Ltd., model: RTM-100]. The adhesive force in the shearing direction was measured when the tensile test was performed at 10 mm / min in the direction.

1 Aluminum plate (C1)
2 Aluminum plate (C2)
3 Spacer 4 Adhesive tape 5 Air gap between the adhesive tape and the aluminum plate (C2)

Claims (8)

The part (c1-1) constituting the adherend (C1) and the other part (c1-2) or the other adherend (C2) constituting the adherend (C1) are attached with an adhesive tape. It is a bonding method to bond
The adhesive tape has a thickness of 1 μm or more and 100 μm on one side of the expandable adhesive layer (A) containing a thermosetting resin, directly or via another layer, and has a thickness of 180 ° C. at room temperature (23 ° C.). It has a pressure-sensitive adhesive layer (B) having a peeling adhesive strength of 1 N / 20 mm or more, and has.
The step [1] of preliminarily adhering the pressure-sensitive adhesive layer (B) constituting the adhesive tape and the portion (c1-1) constituting the adherend (C1), and at least the expandable adhesive. By stimulating and inflating the layer (A), the expanded inflatable adhesive layer (A) constituting the adhesive tape and the site (c1-2) constituting the adherend (C1) or the covering. A bonding method comprising a step [2] of bonding with a body (C2). The expansion rate in the thickness direction of the expandable adhesive layer (A) [thickness of the expandable adhesive layer (A1) after heating / thickness of the expandable adhesive layer (A) before heating] × 100 The bonding method according to claim 1, which is 150% or more. Shear storage elastic modulus G measured by the dynamic viscoelastic spectrum of the pressure-sensitive adhesive layer (B) at 1 Hz and 23 ° C. ₂₃ Is 1.0 × 10 ³ ~ 5.0 × 10 ⁷ The bonding method according to claim 1 or 2, which is in the range of Pa. The bonding method according to any one of claims 1 to 3, wherein the expandable adhesive layer (A) has a thickness of 1 μm or more. The site (c1-1) constituting the adherend (C1) and the other site (c1-2) or the other adherend (C2) constituting the adherend (C1) are attached with an adhesive tape . It is a method of manufacturing glued articles.
The adhesive tape has a thickness of 1 μm or more and 100 μm on one side of the expandable adhesive layer (A) containing a thermosetting resin, directly or via another layer, and has a thickness of 180 ° C. at room temperature (23 ° C.). It has a pressure-sensitive adhesive layer (B) having a peeling adhesive strength of 1 N / 20 mm or more, and has.
The step [1] of preliminarily adhering the pressure-sensitive adhesive layer (B) constituting the adhesive tape and the portion (c1-1) constituting the adherend (C1), and at least the expandable adhesive. By stimulating and expanding the layer (A), the expanded inflatable adhesive layer (A) constituting the adhesive tape and the site (c1-2) constituting the adherend (C1) or the covering. A method for producing an article, which comprises a step [2] of adhering to a body (C2). The expansion rate in the thickness direction of the expandable adhesive layer (A) [thickness of the expandable adhesive layer (A1) after heating / thickness of the expandable adhesive layer (A) before heating] × 100 The method for manufacturing an article according to claim 5, which is 150% or more. Shear storage elastic modulus G measured by the dynamic viscoelastic spectrum of the pressure-sensitive adhesive layer (B) at 1 Hz and 23 ° C. ₂₃ Is 1.0 × 10 ³ ~ 5.0 × 10 ⁷ The method for manufacturing an article according to claim 5 or 6, which is in the range of Pa. The method for producing an article according to any one of claims 5 to 7, wherein the expandable adhesive layer (A) has a thickness of 1 μm or more.

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