JP6030288B2 - Thermosetting thermally expandable adhesive sheet and method for producing the same - Google Patents

Description

  The present disclosure relates to an adhesive sheet for bonding these elements to each other while filling a space between the two elements, and a manufacturing method thereof.

  Epoxy adhesives are widely used for structural bonding because they have excellent heat resistance and high adhesive strength. Various epoxy adhesives have been developed that have a high glass transition temperature (Tg) and / or a low coefficient of thermal expansion (CTE). Liquid epoxy adhesives can be manufactured with simple manufacturing equipment and have many uses. However, liquid epoxy adhesives may cause problems in workability during use, such as being required to be accurate in viscosity adjustment and coating.

  For example, an IPM (Interior Permanent Magnet) motor has a rotor core, and a magnet is inserted into a slot of the rotor core. FIG. 1 is a schematic sectional view of an IPM motor. In FIG. 1, the IPM motor 100 includes a rotor core 120 and a coil 130 disposed around the rotor core 120, and a magnet 110 is embedded in the rotor core 120. The magnet is generally adhered to the rotor core using a liquid epoxy adhesive or a liquid silicone adhesive. When the magnet is bonded to the rotor core using such a liquid adhesive, the magnet coated with the liquid adhesive is inserted into the slot of the rotor core. However, since the rotor core slot size is almost the same as the magnet size (the clearance between the inner wall of the rotor core slot and the magnet is only 80 to 150 μm), most of the liquid adhesive coated on the magnet is placed inside the slot. Therefore, it is discarded without contributing to the adhesion between the magnet and the rotor core.

  If the insertion angle of the magnet is not appropriate, a sufficient amount of liquid adhesive may not remain on the surface of the magnet inserted into the slot or a part thereof to bond the magnet and the rotor core with sufficient strength. Further, the rotor core expands under a high temperature atmosphere used for curing the liquid adhesive, and the clearance between the inner wall of the slot of the rotor core and the magnet is further reduced. As a result, a part of the uncured liquid adhesive may be discharged out of the slot, and the amount of adhesive inside the slot may be reduced. Thus, it has heretofore been difficult to bond the magnet and the rotor core with high reliability.

  Patent Document 1 (Japanese Patent Laid-Open No. 5-179213) describes “an expandable adhesive comprising a liquid or viscous semi-solid uncured adhesive and an expandable material”.

  Patent Document 2 (Japanese Patent Laid-Open No. 2007-106963) states that “(a) a film-forming resin that is solid at room temperature, (b) a liquid or semi-solid epoxy resin at room temperature, (c) a latent curing agent, (d "A heat-expandable sheet-like adhesive composition characterized in that it is formed by forming a film of a component comprising (a) a thermally expandable capsule and (e) a lubricating fine particle powder".

  U.S. Patent Application Publication No. 2004/0266899 describes a "expandable epoxy resin system modified with a thermoplastic polymer".

  Patent Document 4 (US Patent Application Publication No. 2006/0188726) describes “a thermosetting thermally expandable composition having high expandability”.

  Patent Document 5 (International Publication No. 2004/60984) describes "epoxy adhesive activated by heat".

  Patent Document 6 (International Publication No. 2010/014565) describes “reinforced expansive epoxy resins”.

Japanese Patent Laid-Open No. 5-179213 JP 2007-106963 A US Patent Application Publication No. 2004/0266899 US Patent Application Publication No. 2006/0188726 International Publication No. 2004/60984 International Publication No. 2010/014565

  The present disclosure is capable of bonding these elements with high reliability while filling a space between two elements, such as a magnet and a rotor core of an IPM motor, And a method for manufacturing the same.

  According to one embodiment of the present disclosure, a base material having a first surface and a second surface opposite to the first surface and having a communication port, and a heat formed on the first surface of the base material A first adhesive layer containing a curable heat-expandable epoxy adhesive, and the thermosetting heat-expandable epoxy adhesive passes through the communication port of the base material when heated, and the second base material of the base material is heated. A thermosetting thermally expandable adhesive sheet is provided that forms a second adhesive layer on the surface.

  According to another embodiment of the present disclosure, a base material having a first surface and a second surface on the opposite side of the first surface and having a communication port is prepared, (a) a thermosetting epoxy resin, applying a thermosetting thermally expandable epoxy adhesive composition comprising b) a latent curing agent, (c) a thermally expandable capsule, and (d) a solvent to the first side of the substrate to form a first adhesive layer Forming a thermosetting thermally expandable adhesive sheet, wherein the thermosetting epoxy resin is soluble in the solvent, and the latent curing agent and the thermally expandable capsule are the A method for producing a thermosetting thermally expandable adhesive sheet that is insoluble in a solvent is provided.

  According to another embodiment of the present disclosure, a method of adhering a first element and a second element, wherein the thermosetting thermally expandable adhesive sheet is bonded to the first element and the second element. The first element and the second element are disposed between the first element and the second element while the thermosetting heat-expandable adhesive sheet is thermally cured to fill a space between the first element and the second element. A method is provided that includes adhering.

  According to another embodiment of the present disclosure, a first element, a second element, and the heat-cured thermosetting thermally expandable adhesive sheet, comprising the thermosetting thermally expandable adhesive sheet comprising the thermosetting An article is provided wherein a space between the first element and the second element is filled and the first element and the second element are bonded.

  The thermosetting thermally expandable adhesive sheet of the present disclosure does not have an adhesive layer on the second surface of the base material in a stage before heating. Therefore, the element to which the adhesive sheet is applied can be easily handled through the first adhesive layer formed on the first surface of the substrate. For example, a magnet to which the thermosetting thermally expandable adhesive sheet of the present disclosure is attached can be smoothly inserted into a narrow slot of the rotor core of the IPM motor. At this time, the surface opposite to the adhesive surface of the adhesive sheet, that is, the surface having no adhesive layer functions as a slip surface when the magnet is inserted into the rotor core.

  The first adhesive layer of the thermosetting thermally expandable adhesive sheet of the present disclosure includes a thermosetting thermally expandable epoxy adhesive, and the thermosetting thermally expandable epoxy adhesive melts and expands when heated. The second adhesive layer is formed on the second surface of the base material through the communication port of the base material. Therefore, when the thermosetting thermally expandable adhesive sheet of the present disclosure is used, the space between the two elements to be bonded is filled with the expanded thermosetting thermally expandable epoxy adhesive at the same time by thermosetting. The elements can be bonded via an adhesive sheet placed between them. For example, by applying the thermosetting heat-expandable adhesive sheet of the present disclosure to a magnet, inserting the magnet into a slot of the rotor core of the IPM motor, and heating, the magnet and rotor core of the IPM motor can be highly reliable. Can be glued. Moreover, unlike the case where a liquid adhesive is used, the thermosetting heat-expandable epoxy adhesive contained in the adhesive sheet can be effectively used for adhesion between two elements.

  The above description should not be construed as disclosing all embodiments of the present invention and all advantages related to the present invention.

It is a schematic sectional drawing of an IPM motor. 1 is a cross-sectional view of a thermosetting thermally expandable adhesive sheet according to an embodiment of the present disclosure. It is sectional drawing which shows a mode that a thermosetting thermally expansible epoxy adhesive expand | swells when the thermosetting thermally expansible adhesive sheet by one embodiment of this indication is heated. It is the schematic which shows a mode that the thermosetting thermal expansion adhesive sheet by one embodiment of this indication is applied to a magnet, and a magnet is inserted in the slot of a rotor core. It is sectional drawing of the test piece produced by the overlap shear strength (OLSS) test of the Example.

  Hereinafter, the present invention will be described in more detail for the purpose of illustrating representative embodiments of the present invention, but the present invention is not limited to these embodiments.

  In FIG. 2, sectional drawing of the thermosetting thermally expansible adhesive sheet of one embodiment of this indication is shown. The thermosetting heat-expandable adhesive sheet 10 has a first surface 22 and a second surface 24 on the opposite side of the first surface, and has a base material 20 having communication ports such as pores, voids, perforations, and the like. And a first adhesive layer 30 including a thermosetting thermally expandable epoxy adhesive formed on the first surface 22. FIG. 3 shows how the thermosetting thermally expandable epoxy adhesive expands when the thermosetting thermally expandable adhesive sheet of one embodiment of the present disclosure is heated. The thermosetting and heat-expandable epoxy adhesive of the first adhesive layer 30 melts and expands when heated, passes through communication holes such as pores, voids, and perforations of the base material 20 to form the second surface of the base material 20. 24 (middle of FIG. 3). As a result, a continuous or discontinuous second adhesive layer 40 is formed on the second surface 24 of the substrate 20 (the lower part of FIG. 3). This thermosetting thermally expandable adhesive sheet has a function of temporarily fixing only the first surface having the first adhesive layer to the adherend in a stage before heating. The function of temporarily fixing the adherend to the adherend is, for example, a normal temperature stickiness, or a stickiness expressed by a short heating process, such as a hot melt adhesive, on the adherend. It means a function capable of temporarily fixing the thermosetting thermally expandable adhesive sheet. The adhesive sheet can be applied to one of the two elements to be bonded using the function of the first surface. After placing the other element in close proximity to the adhesive sheet application surface of this element (the other element may not be in contact with the adhesive sheet application surface), heating the adhesive sheet to a predetermined temperature will cause thermosetting The expansion of the thermally expandable epoxy adhesive increases the dimension of at least one dimension among the length, width, and thickness of the adhesive sheet. As a result, the space between the two elements can be filled, and these two elements can be bonded to each other by the adhesive layer formed on both the first surface and the second surface of the substrate.

  As a base material having a communication port, various conventionally known base materials such as paper, nonwoven fabric, a porous film containing a polymer such as polytetrafluoroethylene, a metal mesh, a punching film, and the like can be used. The communication port means one or more openings that are spatially continuous and connect the first surface and the second surface of the substrate. The size of the communication port can be determined so that the latent curing agent described later can pass through. If the size of the communication port is so small that the latent curing agent cannot pass, the thermosetting epoxy resin contained in the thermosetting thermally expandable epoxy adhesive and the latent curing agent may be separated, resulting in poor curing. is there. For example, in the case of a circular or substantially circular communication port, the diameter is advantageously, for example, about 1 μm or more, or about 10 μm or more. When it is desired to impart slidability to the element to which the adhesive sheet is applied, it is advantageous to use a substrate having a low surface frictional force, such as a nonwoven fabric or a porous polytetrafluoroethylene film. It is particularly advantageous to use a non-woven fabric as a substrate having a small surface frictional force because of its low cost. Surface friction using a slipping agent or the like may be performed on the base material to reduce the surface frictional force.

The thickness of the base material is such that the thermosetting heat-expandable epoxy adhesive can reach the second surface of the base material through the communication port of the base material when heated, and is thermosetting when the adhesive sheet is manufactured. The value can be set such that the thermally expandable epoxy adhesive does not leach into the second surface of the substrate. The thickness of the substrate can be, for example, about 1 μm or more, about 5 μm or more, or about 10 μm or more, about 5 mm or less, about 2 mm or less, or about 1 mm or less. In applications where an adhesive sheet is inserted into a narrow gap, such as the adhesion of a magnet and a rotor core of an IPM motor, for example, it can be about 1 μm or more, or about 5 μm or more, about 200 μm or less, or about 100 μm or less. . When the nonwoven fabric is used as the substrate, the basis weight of the nonwoven fabric may be, for example, about 2 g / m ² or more, or about 4 g / m ² or more, about 200 g / m ² or less, or about 100 g / m ² or less. it can.

  The first adhesive layer formed on the first surface of the substrate includes a thermosetting thermally expandable epoxy adhesive. The first adhesive layer provides the first surface with a function of temporarily fixing to the adherend as described above. The thermosetting thermally expandable epoxy adhesive can include (a) a thermosetting epoxy resin, (b) a latent curing agent, and (c) a thermally expandable capsule. The latent curing agent can increase the adhesive force of the adhesive layer by curing the thermosetting thermally expandable epoxy adhesive by heating. The thermally expandable capsule promotes the expansion of the thermosetting thermally expandable epoxy adhesive melted by heating. The thickness of the first adhesive layer can be, for example, about 1 μm or more, about 5 μm or more, or about 10 μm or more, about 5 mm or less, about 2 mm or less, or about 1 mm or less. In applications where an adhesive sheet is inserted into a narrow gap, such as the adhesion of a magnet and a rotor core of an IPM motor, for example, it can be about 1 μm or more, or about 5 μm or more, about 200 μm or less, or about 100 μm or less. .

  The physical properties of the thermosetting epoxy resin used, such as fluidity, plasticity, softening point, melt viscosity, glass transition point (Tg), storage elastic modulus, etc., are functions that the thermosetting thermally expandable adhesive sheet of the present disclosure has, That is, it is considered to be closely related to both the temporary fixing function of the first adhesive layer before heating and the function of forming the second adhesive layer during heating. For example, the softening point of the thermosetting epoxy resin, the activation temperature of the latent curing agent described later, and the expansion start temperature of the thermally expandable capsule described later are closely related to each other. More specifically, in order to effectively exert the function of the thermosetting thermally expandable adhesive sheet of the present disclosure, the softening point of the thermosetting epoxy resin is equal to or lower than the activation temperature of the latent curing agent, And it is advantageous that the temperature is not higher than the expansion start temperature of the thermally expandable capsule. If the softening point of the thermosetting epoxy resin is lower than the activation temperature of the latent curing agent, when the manufacturing process of the thermosetting thermally expandable adhesive sheet includes melt coating or solution coating, these coating processes and It can prevent that a thermosetting epoxy resin gelatinizes during the accompanying drying process. If the softening point of the thermosetting epoxy resin is below the expansion start temperature of the thermally expandable capsule, the resin exhibits fluidity at the temperature at which the thermally expandable capsule expands. Can be inflated. The softening point of the thermosetting epoxy resin is measured using a ring and ball softening point test method defined in JIS K 2207.

  In order to adjust the softening point of the thermosetting epoxy resin, a plurality of epoxy resins may be mixed. A thermosetting epoxy resin having a relatively low softening point or a liquid thermosetting epoxy resin can impart normal temperature adhesiveness or adhesiveness that is manifested by a short heating process to the thermosetting epoxy resin, It also contributes to increasing fluidity during heating. A thermosetting epoxy resin having a relatively high softening point or semi-solid maintains the shape of the first adhesive layer at room temperature, and the thermosetting thermally expandable epoxy adhesive penetrates the substrate excessively before heating. This can be prevented or suppressed. When such a mixture of thermosetting epoxy resins is used, the physical properties of the thermosetting epoxy resin can be easily and finely adjusted.

  Examples of thermosetting epoxy resins that can be used include bisphenol epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins, epoxy resins having an aliphatic skeleton such as hexanediol diglycidyl ether, and glycidyl amines such as triglycidylaminophenol. Type epoxy resins, phenol novolac epoxy resins, cresol novolac epoxy resins and other novolak epoxy resins, brominated epoxy resins, alicyclic epoxy resins, and mixtures thereof can be used, but are not limited thereto. The thermosetting epoxy resin may further contain a phenoxy resin (polyhydroxy polyether synthesized from bisphenols and epichlorohydrin) as a thermoplastic component. When a phenoxy resin is added, the film-forming property of a thermosetting thermally expandable epoxy adhesive may be improved.

  The number average molecular weight of the thermosetting epoxy resin is generally about 100 or more, or about 300 or more in terms of standard polystyrene, and can be about 100,000 or less, or about 60000 or less. The epoxy equivalent of the thermosetting epoxy resin can generally be about 50 g / equivalent or more, or about 80 g / equivalent or more, about 50000 g / equivalent or less, or about 30000 g / equivalent or less. A thermosetting epoxy resin is a basic component of a thermosetting thermally expandable epoxy adhesive. Therefore, the amount of other components is described based on 100 parts by mass of the thermosetting epoxy resin.

  The latent curing agent is a curing agent that does not have the activity of curing the thermosetting epoxy resin at room temperature, but can be activated by heating to cure the thermosetting thermally expandable epoxy adhesive. For example, a conventionally known fine-grained latent curing agent is insoluble in a thermosetting epoxy resin at room temperature, and can be solubilized by heating to cure the thermosetting epoxy resin. Conventional latent curing agents known as latent curing agents such as dicyandiamide and its derivatives, hydrazide compounds, boron trifluoride-amine complexes, finely divided imidazole compounds at room temperature, reaction of amine compounds with epoxy compounds A product (amine-epoxy adduct), a reaction product of an amine compound with an isocyanate compound or a urea compound (urea adduct), and the like can be used. A combination of two or more latent hardeners may be used. The latent curing agent is about 0.5 parts by mass or more, about 1 part by mass or more, about 2 parts by mass or more, or about 30 parts by mass or less, about 20 parts by mass or less based on 100 parts by mass of the thermosetting epoxy resin. Or about 10 parts by weight or less. A combination of dicyandiamide and an amine-epoxy adduct (for example, trade name PN-50, manufactured by Ajinomoto Fine Techno Co., Ltd.) is particularly advantageous because it exhibits good storage stability at room temperature and has a suitable activation temperature. it can.

  As described above, the activation temperature of the latent curing agent is advantageously selected so that the softening point of the thermosetting epoxy resin is equal to or lower than the activation temperature of the latent curing agent. Here, the activation temperature of the latent curing agent is defined as a temperature measured using a DSC (differential scanning calorimeter) (measurement condition: a mixture of the used thermosetting epoxy resin and the latent curing agent). As a sample, the temperature is raised from room temperature at 10 ° C./min). The activation temperature of the latent curing agent can be selected from the range of, for example, about 80 ° C. or higher, or about 120 ° C. or higher, about 180 ° C. or lower, or about 160 ° C. or lower.

  The heat-expandable capsule is a microcapsule in which a thermoplastic resin having gas barrier properties is used as a shell, and a heat-expanding agent is included inside the shell. When the heat-expandable capsule is heated, the thermoplastic resin in the shell is softened, and the volume of the heat-expandable agent is increased, so that the capsule expands. For example, a low-boiling substance is used as the thermal expansion agent, and vaporization of the low-boiling substance is used for expansion of the capsule. The expansion start temperature of the thermally expandable capsule is desirably lower than the activation temperature of the latent curing agent. By doing in this way, it can prevent or control more effectively that thermosetting thermally expansible epoxy adhesive hardens before expanding. In addition, as described above, the expansion start temperature of the thermally expandable capsule is advantageously selected so that the softening point of the thermosetting epoxy resin is equal to or lower than the expansion start temperature of the thermally expandable capsule. Here, the expansion start temperature of the thermally expandable capsule is a temperature at which the volume change of the thermally expandable capsule occurs. The expansion start temperature of the thermally expandable capsule can be selected from the range of, for example, about 70 ° C. or higher, or about 100 ° C. or higher, about 200 ° C. or lower, or about 180 ° C. or lower.

  The amount and volume expansion coefficient of the thermally expandable capsule can be appropriately determined according to the strength and adhesive force required for the cured adhesive layer, the expansion coefficient required for the adhesive sheet, and the like. For example, the thermally expandable capsule is about 0.1 parts by mass or more, about 0.5 parts by mass or more, about 1 part by mass or more, about 50 parts by mass or less, about 30 parts by mass based on 100 parts by mass of the thermosetting epoxy resin. It can be used in an amount of no more than parts by weight, or no more than about 20 parts by weight. The volume expansion coefficient of the thermally expandable capsule can be, for example, about 2 times or more, or about 5 times or more, about 100 times or less, or about 50 times or less.

  Thermosetting heat-expandable epoxy adhesives include, as optional components, phenolic antioxidants, antioxidants such as sulfur antioxidants, reinforcing agents such as core-shell type reinforcing agents, and silanes such as epoxy-modified alkoxysilanes. It may further contain a coupling agent, a thixotropic agent such as fumed silica, a thermally conductive filler such as alumina and boron nitride.

  The thickness of the thermosetting thermally expandable adhesive sheet including the substrate and the first adhesive layer is, for example, about 1 μm or more, about 5 μm or more, or about 10 μm or more, about 5 mm or less, about 2 mm or less, or about 1 mm or less. can do. In applications where an adhesive sheet is inserted into a narrow gap, such as the adhesion of a magnet and a rotor core of an IPM motor, for example, it can be about 1 μm or more, or about 5 μm or more, about 200 μm or less, or about 100 μm or less. . The thermally expandable sheet may include a liner on the first adhesive layer.

  The thermosetting heat-expandable adhesive sheet of the present disclosure includes a thermosetting heat-expandable epoxy adhesive containing the thermosetting epoxy resin, a latent curing agent, a heat-expandable capsule, and the optional components as necessary. It can manufacture by applying an agent composition to the 1st surface of the said base material, and forming a 1st contact bonding layer. The thermosetting heat-expandable epoxy adhesive composition can be applied onto the substrate by a conventionally known method such as coating such as bar coating, roll coating, melt extrusion and the like. When the melt viscosity of the thermosetting epoxy resin is low, the melt coating method can be used without a solvent. A first adhesive layer is formed on the first surface of the substrate by applying a thermosetting thermally expandable epoxy adhesive composition on the liner to form a first adhesive layer and laminating the substrate thereon. You may transcribe.

  When a thin first adhesive layer or a first adhesive layer of uniform thickness is required, a solvent is added to the thermosetting thermally expandable epoxy adhesive composition to adjust the viscosity of the composition, and by solution coating method It is advantageous to form the first adhesive layer by applying the composition to the first side or liner of the substrate and drying as necessary. In this case, in order to produce an adhesive sheet having excellent storage stability, the thermosetting epoxy resin is soluble in the solvent used and the latent curing agent and the thermally expandable capsule are insoluble. Is desirable. Examples of such a solvent include esters such as ethyl acetate and butyl acetate.

  A thixotropic agent such as fumed silica can be used in place of or in combination with the above solvent to improve the coatability of the thermosetting thermally expandable epoxy adhesive composition. In addition, when a thixotropic agent is used, it is possible to prevent or suppress the thermosetting and heat-expandable epoxy adhesive from passing through the communication port of the substrate, for example, pores, voids, perforations, etc., when storing the adhesive sheet.

  The thermosetting thermally expandable adhesive sheet of the present disclosure can be used for various double-sided adhesive applications that require filling the space between two elements. For example, as shown in FIG. 4, the adhesive sheet 10 is applied on the magnet 110 so that the first adhesive layer of the thermosetting and thermally expandable adhesive sheet 10 is in contact with the magnet 110, and the magnet is applied to the rotor of the IPM motor. The magnet 110 can be bonded to the rotor core 120 by being inserted into the slot 140 of the core 120 and heated, for example, at 120 to 180 ° C. for 10 minutes to 2 hours.

  In this example, the materials shown in Table 1 below were used.

<Overlap shear strength (OLSS) test>
FIG. 5 shows a cross section of a test piece prepared by an overlap shear strength (OLSS) test. Heat is applied so that the first adhesive layer 30 is in contact with one of the steel plates inside the rectangular parallelepiped space defined by the two SPCC-SB steel plates 50 and the spacers 60 that are surface-treated by wiping with methyl ethyl ketone (MEK). A curable thermally expandable adhesive sheet 10 was placed. The steel plate had a length of 50 mm, a width of 25 mm, and a thickness of 1.6 mm, and the adhesive sheet was a rectangle of 12.5 mm × 25 mm. The thickness of the spacer was twice as large as the adhesive sheet (100 μm) or three times as thick as the adhesive sheet (150 μm). Next, it heated at 160 degreeC for 30 minute (s), the thermosetting heat-expandable epoxy adhesive of the adhesive sheet was fuse | melted, expanded, and hardened, and the test piece of the OLSS test was produced. The shear strength when the two steel plates of the test piece were pulled in opposite directions at 25 ° C. and a tensile speed of 5 mm / min was defined as OLSS (MPa).

<Preparation of thermosetting thermally expandable adhesive sheet>
A thermosetting thermally expandable epoxy adhesive composition having the composition shown in Table 2 below was applied to a liner (SLB-50WD) using a bar coater, 3 minutes at 65 ° C, and then 3 minutes at 80 ° C. Dried. The thickness of the adhesive layer after drying was 30 μm. Next, a nonwoven fabric was laminated on the adhesive layer formed on the liner. Thus, a thermosetting thermally expandable adhesive sheet having a thickness of 50 μm was produced.

  The results are shown in Table 2 below.

DESCRIPTION OF SYMBOLS 10 Thermosetting thermally expansible adhesive sheet 20 Base material 22 1st surface 24 2nd surface 30 1st adhesive layer 40 2nd adhesive layer 50 Steel plate 60 Spacer 100 IPM motor 110 Magnet 120 Rotor core 130 Coil 140 Slot
Some of the embodiments of the present invention are listed in items 1-7 below.
[1]
A substrate having a first surface and a second surface on the opposite side of the first surface, and having a communication port;
A first adhesive layer comprising a thermosetting thermally expandable epoxy adhesive formed on the first surface of the substrate, wherein the thermosetting thermally expandable epoxy adhesive is heated when heated. A thermosetting heat-expandable adhesive sheet that passes through the communication port and forms a second adhesive layer on the second surface of the substrate.
[2]
The thermosetting thermally expandable epoxy adhesive is
(A) thermosetting epoxy resin,
(B) a latent curing agent, and
(C) Thermally expandable capsule
The thermosetting heat-expandable adhesive sheet according to item 1, comprising:
[3]
The thermosetting heat according to any one of Items 1 and 2, wherein a softening point of the thermosetting epoxy resin is not higher than an activation temperature of the latent hardener and not higher than an expansion start temperature of the thermally expandable capsule. Expandable adhesive sheet.
[4]
The thermosetting thermally expandable adhesive sheet according to any one of items 1 to 3, wherein the substrate is a nonwoven fabric.
[5]
A first surface and a substrate having a second surface on the opposite side of the first surface and having a communication port are prepared,
A thermosetting heat-expandable epoxy adhesive composition comprising (a) a thermosetting epoxy resin, (b) a latent curing agent, (c) a heat-expandable capsule, and (d) a solvent is formed on the first substrate. Apply to the surface to form the first adhesive layer
A method for producing a thermosetting thermally expandable adhesive sheet, comprising:
The method for producing a thermosetting thermally expandable adhesive sheet, wherein the thermosetting epoxy resin is soluble in the solvent, and the latent curing agent and the thermally expandable capsule are insoluble in the solvent.
[6]
A method of bonding a first element and a second element, comprising:
The thermosetting thermally expandable adhesive sheet according to any one of items 1 to 4 is disposed between the first element and the second element,
Bonding the first element and the second element while thermally curing the thermosetting thermally expandable adhesive sheet to fill a space between the first element and the second element; Including.
[7]
A first element, a second element, and a thermosetting thermally expandable adhesive sheet according to any one of items 1 to 4, wherein the thermosetting thermally expandable adhesive sheet is thermally cured. An article in which a space between the first element and the second element is filled and the first element and the second element are bonded.

Claims (6)

A thermosetting thermally expandable adhesive sheet that bonds the first adherend and the second adherend by being temporarily fixed to the first adherend and heated,
Before the temporary fixing,
A substrate having a first surface and a second surface on the opposite side of the first surface and having a communication port;
A first adhesive layer including a thermosetting thermally expandable epoxy adhesive formed on the first surface of the first surface and the second surface of the substrate;
After bonding the first adherend and the second adherend,
In addition to the base material and the first adhesive layer, the thermosetting heat-expandable epoxy adhesive is formed on the second surface of the base material through the communication port of the base material. A thermosetting thermally expandable adhesive sheet having an adhesive layer. The thermosetting thermally expandable epoxy adhesive is
(A) thermosetting epoxy resin,
The thermosetting thermally expandable adhesive sheet according to claim 1, comprising (b) a latent curing agent, and (c) a thermally expandable capsule.   The thermosetting thermally expandable adhesive sheet according to claim 2, wherein a softening point of the thermosetting epoxy resin is not higher than an activation temperature of the latent hardener and not higher than an expansion start temperature of the thermally expandable capsule. .   The thermosetting thermally expandable adhesive sheet according to any one of claims 1 to 3, wherein the substrate is a nonwoven fabric.   The thermosetting thermally expandable adhesive sheet according to any one of claims 1 to 3, wherein the thermosetting thermally expandable epoxy adhesive contains a thixotropic agent. A method of bonding the first adherend and the second adherend,
Disposing the thermosetting thermally expandable adhesive sheet according to any one of claims 1 to 5 between the first adherend and the second adherend,
The first adherend and the second adherence are made by thermally curing the thermosetting thermally expandable adhesive sheet to fill a space between the first adherend and the second adherend. Adhering the adherend.

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