Easily degradable resin composition, structure provided with cured product of easily degradable resin composition, method for disassembling structure, and method for recycling material forming structure

Abstract

An easily degradable resin composition according to the present invention contains a thermosetting resin, and exhibits an adhesion strength ratio (S2 / S1) of 0.30 or less as measured by the following procedure. [Procedure] The easily degradable resin composition is molded on a copper substrate at 175°C and at 6.9 MPa for 120 seconds, and is then subjected to post-curing for four hours at 175°C to obtain a test piece. By using the test piece, the adhesion strength [N / mm2] obtained when the shearing adhesion to the copper substrate is measured at a rate of 300 µm / second at room temperature is denoted as S1 [N / mm2]. Further, after the test piece is heated for 30 minutes at 300°C, the adhesion strength [N / mm2] obtained when the shear adhesion to the copper substrate is measured at a rate of 300 µm / second at room temperature is denoted as S2 [N / mm2].

Description

Easily dismantled resin composition, structure comprising a cured product of the easily dismantled resin composition, method for dismantling a structure, and method for recycling materials constituting the structure

[0001] The present invention relates to an easily dismantlable resin composition, a structure comprising a cured product of the easily dismantlable resin composition, a method for dismantling a structure, and a method for recycling materials constituting the structure.

[0002] In recent years, the automotive industry has been actively promoting the electrification of vehicles in order to address global climate change and realize a carbon-neutral society. The neodymium magnets used in many of these electric vehicle motors contain rare elements known as rare earths, such as neodymium and dysprosium. However, there are concerns about the uneven distribution of rare earth resources and price fluctuations due to supply and demand balances, and the burden on the ecosystem caused by mining and smelting, making reducing their use a challenge. As a result, the automotive industry is focusing on technologies related to the reuse of rare earths as a way to make effective use of resources.

[0003] For example, it is known to remove, disassemble, and reuse magnets from motors that could not be installed in automobiles that did not meet shipping standards. Also, for example, Patent Document 1 discloses a method in which the rotor is heated to the higher of the Curie temperature or the incineration temperature of the adhesive, and then vibrations are applied to the metal plate on the end face of the rotor so that the metal plate resonates, thereby removing the adhesive and the magnets from the holes.

[0004] Japanese Patent Application Laid-Open No. 2015-216777

[0005] However, in the conventional technology disclosed in Patent Document 1, the process of extracting rare earth elements from motor magnets requires manual disassembly and extraction of the magnets, leaving room for improvement in terms of simplifying the process and reducing recycling costs. Furthermore, when attempting to extract the magnets by incinerating the adhesive by heating at high temperatures (approximately 600 to 700°C), carbon dioxide is generated unless the thermal energy is clean.

[0006] The present inventors have conducted extensive research to solve these problems and have found that it is effective for a cured product of a resin composition used for rotor fixation, etc., to have a predetermined structure and predetermined physical properties. Specifically, they have found that, among cured products obtained by curing a resin composition, controlling adhesion to copper can affect dismantling properties, and have devised a new index.

[0007] The present invention provides the following easily dismantlable resin composition, a structure including a cured product of the easily dismantlable resin composition, a method for dismantling a structure, and a method for recycling materials constituting the structure.

[0008] [1] An easily dismantlable resin composition containing a thermosetting resin, wherein the adhesion strength ratio (S2 / S1) measured by the following procedure is 0.30 or less. [Procedure] The easily dismantlable resin composition is molded onto a copper substrate under conditions of 175°C, 6.9 MPa, and 120 seconds, and then post-cured at 175°C for 4 hours to obtain a test piece. Using the test piece, the shear adhesion to the copper substrate is measured at room temperature at a rate of 300 μm / s, and the adhesion strength [N / mm ２ ] to S1 [N / mm ２ Furthermore, the test piece was heated at 300°C for 30 minutes, and then the shear adhesion to the copper substrate was measured at room temperature at a rate of 300 µm / sec. ２ ] to S2 [N / mm ２ [2] The easily dismantlable resin composition according to [1], wherein the adhesive strength (S2) measured by the above procedure is 3.0 N / mm ２[3] The easily dismantlable resin composition according to [1] or [2], wherein the easily dismantlable resin composition is molded under conditions of 175°C, 6.9 MPa, and 120 seconds, and further post-cured at 175°C for 4 hours, and the cured product has a linear expansion coefficient α2 of 46 ppm / °C or more in the temperature range of 190°C to 230°C. [4] The easily dismantlable resin composition according to any one of [1] to [3], wherein the easily dismantlable resin composition is molded under conditions of 175°C, 6.9 MPa, and 120 seconds, and further post-cured at 175°C for 4 hours, and the cured product has a linear expansion coefficient α3 of 60 ppm / °C or more in the temperature range of 250°C to 260°C. [5] The easily dismantlable resin composition according to any one of [1] to [4], wherein the thermosetting resin comprises one or more selected from epoxy resins, phenoxy resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, cyanate resins, bismaleimide resins, and acrylic resins. [6] The easily dismantlable resin composition according to any one of [1] to [5], further comprising a curing agent. [7] The easily dismantlable resin composition according to [6], wherein the curing agent comprises a phenolic curing agent. [8] The easily dismantlable resin composition according to any one of [1] to [7], further comprising a thermally expandable inorganic material, the content of which is 5 to 98 mass% relative to the total amount of the easily dismantlable resin composition. [9] The easily dismantlable resin composition according to [8], wherein the thermally expandable inorganic material comprises one or more selected from the group consisting of crystalline silica, crystalline aluminum phosphate, and derivatives thereof.

[10] The easily dismantlable resin composition according to [8] or [9], wherein the thermally expandable inorganic material comprises one or more selected from the group consisting of quartz silica, cristobalite silica, tridymite silica, berlinite aluminum phosphate, tridulphite aluminum phosphate, crystallite aluminum phosphate, and carnegie.

[11] The easily dismantlable resin composition according to any one of [1] to

[10] , further comprising aluminum hydroxide.

[12] The easily dismantlable resin composition according to

[11] , wherein the content of the aluminum hydroxide is 1 mass% or more relative to the total amount of the easily dismantlable resin composition.

[13] The easily dismantlable resin composition according to any one of [1] to

[12] , comprising one or more selected from a thermally expandable inorganic material, an inorganic filler, and aluminum hydroxide, wherein the total content of the thermally expandable inorganic material, the inorganic filler, and the aluminum hydroxide is 60 mass% or more relative to the total amount of the easily dismantlable resin composition.

[14] The easily dismantlable resin composition according to any one of [1] to

[13] , wherein the easily dismantlable resin composition is in the form of powder, granules, or tablets.

[15] A structure comprising a cured product of the easily dismantlable resin composition according to any one of [1] to

[14] .

[16] A method for dismantling a structure according to

[15] , comprising the step of heating the structure to 200°C or higher to dismantle the cured product of the easily dismantled resin composition.

[17] A method for recycling materials constituting the structure according to

[15] , comprising the steps of heating the structure to 200°C or higher to dismantle the cured product of the easily dismantled resin composition, and recovering the materials from the structure.

[18] The easily dismantled resin composition according to any one of [1] to

[14] , wherein the easily dismantled resin composition is used to form a fixed member of a rotor comprising: a rotor core fixed to a rotating shaft and having a plurality of holes arranged along the periphery of the rotating shaft; magnets inserted into the holes; and a fixed member provided in a space between the holes and the magnets.

[19] A rotor comprising a cured product of the easily dismantled resin composition according to

[18] as the fixed member.

[20] The rotor dismantling method according to

[19] , comprising the step of heating the rotor to 200°C or higher to dismantle the cured product of the easily dismantlable resin composition.

[21] A method for recycling materials constituting the rotor according to

[19] , comprising the steps of heating the rotor to 200°C or higher to dismantle the cured product of the easily dismantlable resin composition, and recovering the materials from the rotor.

[22] The recycling method according to

[21] , wherein the material is one or more selected from the group consisting of the magnet inserted in the hole and an electromagnetic steel plate.

[23] The easily dismantlable resin composition according to any one of [1] to

[14] , wherein the easily dismantlable resin composition is used to form a sealing member of a stator having a stator core having a plurality of teeth and a plurality of slots formed alternately in the circumferential direction, a coil wound in the slot and housed in the slot, the coil having a pair of coil ends protruding from the stator core on both axial sides, and a sealing member provided in the slot to cover the coil.

[24] A stator comprising a cured product of the easily dismantlable resin composition according to

[23] as the sealing member.

[25] A method for dismantling a stator according to

[24] , comprising the step of heating the stator to 200°C or higher to dismantle the cured product of the easily dismantled resin composition.

[26] A method for recycling materials constituting the stator according to

[24] , comprising the steps of heating the stator to 200°C or higher to dismantle the cured product of the easily dismantled resin composition, and recovering the materials from the stator.

[27] The recycling method according to

[26] , wherein the material is one or more selected from the group consisting of a coil and an electromagnetic steel plate.

[28] The easily dismantled resin composition according to any one of [1] to

[14] , used to form the sealing member of a power module comprising a wiring board, a plurality of electronic components mounted on the wiring board, and a sealing member that seals the electronic components.

[29] A power module comprising a cured product of the easily dismantled resin composition according to

[28] as the sealing member.

[30] The method for dismantling a power module according to

[29] , comprising the step of heating the power module to 200°C or higher to dismantle the cured product of the easily dismantled resin composition.

[31] The method for recycling a material constituting the power module according to

[29] , comprising the steps of heating the power module to 200°C or higher to dismantle the cured product of the easily dismantled resin composition, and recovering the material from the power module.

[32] The method for recycling according to

[31] , wherein the material is a metal lead frame.

[0009] According to the present invention, the cured product of the easily dismantled resin composition containing a thermosetting resin can be easily dismantled, thereby improving the recyclability of materials constituting a structure including the cured product of the easily dismantled resin composition.

[0010] Fig. 4 is a plan view showing an example of a rotor; Fig. 5 is a cross-sectional view showing the rotor shown in Fig. 1; Fig. 6 is an enlarged cross-sectional view showing the rotor shown in Fig. 1; Fig. 7 is a cross-sectional view showing an example of a motor in a direction perpendicular to the rotation axis direction; Fig. 8 is a longitudinal cross-sectional view in the rotation axis direction of the motor shown in Fig. 4; Fig. 9 is an enlarged view showing the periphery of a slot of the motor shown in Fig. 4; Fig. 10 is a schematic cross-sectional view showing an example of a power module;

[0011] In this specification, the notation "a to b" in the description of a numerical range means from a to b, unless otherwise specified. For example, "1 to 5 mass %" means "1 mass % to 5 mass %." Furthermore, the lower limit and upper limit of a numerical range can be arbitrarily combined with the lower limit and upper limit of another numerical range.

[0012] Unless otherwise specified, each of the components and materials exemplified in this specification may be used alone or in combination of two or more.

[0013] Hereinafter, embodiments of the present invention will be described in detail.

[0014] 1. Easily Dismantlable Resin Composition The easily dismantlable resin composition of the present embodiment (hereinafter also simply referred to as "resin composition") contains a thermosetting resin, and has an adhesion strength ratio (S2 / S1) of 0.30 or less as measured by the following procedure.

[0015] [Procedure] The easily dismantlable resin composition was molded onto a copper substrate at 175°C, 6.9 MPa, and for 120 seconds, and then post-cured at 175°C for 4 hours to obtain a test specimen. The shear adhesion between the test specimen and the copper substrate was measured at room temperature at a rate of 300 μm / sec, and the adhesion strength [N / mm ２ ] to S1 [N / mm ２ Furthermore, the test piece was heated at 300°C for 30 minutes, and then the shear adhesion to the copper substrate was measured at room temperature at a rate of 300 µm / sec. ２ ] to S2 [N / mm ２ ]

[0016] That is, when the easily dismantlable resin composition of the present embodiment is heated, the adhesive strength of the cured product to other materials decreases, which makes it easier to peel off, separate, etc., and makes the cured product easier to dismantle.

[0017] In this embodiment, the adhesion strength ratio (S2 / S1) is 0.30 or less, preferably 0.25 or less, more preferably 0.20 or less, even more preferably 0.15 or less, and particularly preferably 0.05 or less. Furthermore, the adhesion strength ratio (S2 / S1) is preferably 0.01 or less, and may be 0.00.

[0018] The adhesive strength (S2) measured by the above procedure is preferably 3.0 N / mm ２ More preferably, it is 2.0 N / mm ２ More preferably, it is 1.0 N / mm ２ More preferably, it is 0.5 N / mm ２The lower limit of the adhesion strength (S2) is not particularly limited, and the test piece may already be peeled from the copper substrate before the adhesion strength is measured. That is, the test piece is intended to be peeled from the copper substrate during heating at 300°C for 30 minutes. In this case, the adhesion strength (S2) is 0 N / mm ２ and the adhesion strength ratio (S2 / S1) is also 0.

[0019] The adhesive strength (S1) measured by the above procedure is preferably 8 N / mm ２ More preferably, 9 N / mm ２ More preferably, it is 10 N / mm ２ More preferably, it is 12 N / mm ２ On the other hand, the upper limit of the adhesion strength (S1) is not particularly limited and is set appropriately depending on the application, but for example, it is 50 N / mm ２ The following may also be used.

[0020] Furthermore, when the easily dismantlable resin composition is molded under conditions of 175°C, 6.9 MPa, and 120 seconds, and then post-cured at 175°C for 4 hours, the cured product has a linear expansion coefficient α2 in the temperature range of 190°C to 230°C of preferably 46 ppm / °C or more, more preferably 50 ppm / °C or more, and even more preferably 55 ppm / °C or more. This makes it easier for the cured product to peel or separate from other materials, improving dismantling properties.

[0021] Furthermore, when the easily dismantlable resin composition is molded under conditions of 175°C, 6.9 MPa, and 120 seconds, and then post-cured at 175°C for 4 hours, the cured product has a linear expansion coefficient α3 in the temperature range of 250 to 260°C of preferably 80 ppm / °C or more, more preferably 100 ppm / °C or more, and even more preferably 200 ppm / °C or more. This makes it easier for the cured product to peel or separate from other materials, improving dismantling properties.

[0022] In this embodiment, "easily dismantlable" means that a cured product obtained by heat-curing the easily dismantlable resin composition of this embodiment can be dismantled by, for example, easily creating cracks in the cured product or easily crushing or separating the cured product. For example, easy dismantling is achieved when a cured product of the easily dismantlable resin composition of this embodiment can be easily separated from the materials in the cured product (such as encapsulated materials). In other words, the cured product can be dismantled without applying excessive external stress that would also place a load on the materials contained in the cured product or without performing chemical treatment using chemicals or the like.

[0023] The easily dismantlable resin composition having the adhesive strength of this embodiment can be realized by selecting the various components constituting the easily dismantlable resin composition and adjusting the contents thereof, etc. Specific examples include controlling the curability of the thermosetting resin (A) and the curing agent (B), selecting the thermally expandable inorganic material (C) described below, and adjusting the contents of the thermally expandable inorganic material (C), the inorganic filler (D), and the flame retardant.

[0024] The components contained in the resin composition of this embodiment will be described below.

[0025] [Thermosetting Resin (A)] The resin composition of this embodiment contains a thermosetting resin (A). Examples of the thermosetting resin (A) include one or more selected from phenolic resins, epoxy resins, phenoxy resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, melamine resins, silicone resins, cyanate resins, maleimide resins, cyanate resins, and acrylic resins. These thermosetting resins can be any monomer, oligomer, or polymer having two or more reactive functional groups per molecule, and the molecular weight and molecular structure thereof are not particularly limited.

[0026] The epoxy resin may be any monomer, oligomer, or polymer having two or more epoxy groups in one molecule, and the molecular weight or molecular structure thereof is not particularly limited. Specific examples of the epoxy resin include novolac epoxy resins such as phenol novolac epoxy resins and cresol novolac epoxy resins; bisphenol epoxy resins such as bisphenol A epoxy resins and bisphenol F epoxy resins; aromatic glycidylamine epoxy resins such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, diaminodiphenylmethane glycidylamine, and aminophenol glycidylamine; hydroquinone epoxy resins; biphenyl epoxy resins; stilbene epoxy resins; triphenolmethane epoxy resins; triphenolpropane epoxy resins; alkyl-modified triphenols; Examples of the thermosetting resin (A) include one or more selected from the group consisting of phenol methane-type epoxy resins, triazine nucleus-containing epoxy resins, dicyclopentadiene-modified phenol-type epoxy resins, naphthol-type epoxy resins, naphthalene-type epoxy resins, naphthylene ether-type epoxy resins, aralkyl-type epoxy resins such as phenol aralkyl-type epoxy resins having a phenylene and / or biphenylene skeleton and naphthol aralkyl-type epoxy resins having a phenylene and / or biphenylene skeleton, and aliphatic epoxy resins such as vinylcyclohexene dioxide, dicyclopentadiene oxide, and alicyclic diepoxy adipide. Of these, the thermosetting resin (A) is preferably an epoxy resin.

[0027] The content of the thermosetting resin (A) is preferably 1% by mass or more and 50% by mass or less, more preferably 2% by mass or more and 30% by mass or less, and even more preferably 5% by mass or more and 20% by mass or less, based on the total amount of the resin composition. By making the content of the thermosetting resin (A) equal to or greater than the above lower limit, the fluidity and moldability of the resin composition can be more effectively improved. Furthermore, by making the content of the thermosetting resin (A) equal to or less than the above upper limit, the curability can be improved and a good cured product can be obtained.

[0028] [Curing Agent (B)] The curing agent (B) of the present embodiment is selected depending on the type of thermosetting resin (A) and is not particularly limited as long as it reacts with the thermosetting resin (A). Specific examples of the curing agent (B) include polyaddition-type curing agents, catalyst-type curing agents, and condensation-type curing agents.

[0029] Specific examples of the curing agent (B) include phenolic curing agents, amines, polyoxystyrenes such as polyparaoxystyrene, alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), acid anhydrides including aromatic acid anhydrides such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), and benzophenonetetracarboxylic acid (BTDA), polymercaptan compounds such as polysulfides, thioesters, and thioethers, isocyanate compounds such as isocyanate prepolymers and blocked isocyanates, and organic acids such as carboxylic acid-containing polyester resins.

[0030] Specific examples of the phenolic curing agent include one or more selected from novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, naphthol novolac resin, aminotriazine novolac resin, novolac resin, and trisphenylmethane-type phenol novolac resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl-type resins such as phenol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton and naphthol aralkyl resins having a phenylene skeleton and / or biphenylene skeleton; bisphenol compounds such as bisphenol A and bisphenol F; and resol-type phenolic resins. From the viewpoint of curability, the hydroxyl equivalent of the phenolic resin-based curing agent is preferably, for example, 90 g / eq or more and 250 g / eq or less.

[0031] Specific examples of the amines include one or more selected from aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylenediamine (MXDA); aromatic polyamines such as diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenylsulfone (DDS); polyamine compounds including dicyandiamide (DICY) and organic acid dihydralazides; alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA), and aromatic acid anhydrides such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), and benzophenonetetracarboxylic acid (BTDA).

[0032] In this embodiment, when an epoxy resin is used as the thermosetting resin (A), it is preferable to combine it with a phenol-based curing agent as the curing agent (B).

[0033] The content of the curing agent (B) is preferably 5 to 50 parts by mass, more preferably 10 to 30 parts by mass, based on 100 parts by mass of the thermosetting resin (A).

[0034] The contents of the thermosetting resin (A) and the curing agent (B) are appropriately set depending on the thermosetting resin (A) and the curing agent (B). For example, the phenolic curing agent as the curing agent (B) and the epoxy resin as the thermosetting resin (A) are adjusted so that the equivalent ratio (EP) / (OH) of the number of epoxy groups (EP) in the total thermosetting resin to the number of phenolic hydroxyl groups (OH) in the total phenolic resin is preferably 0.8 or more and 1.6 or less, more preferably 0.9 or more and 1.3 or less, and even more preferably 1.0 or more and 1.2 or less. When the equivalent ratio is within the above range, the curing characteristics of the resulting resin composition of this embodiment can be improved.

[0035] The resin composition of the present embodiment may further contain the following components.

[0036] [Thermal Expandable Inorganic Material (C)] The thermal expandable inorganic material (C) is a material that undergoes phase conversion upon heating and causes volume expansion. By using the thermal expandable inorganic material (C), the cured product of the resin composition of this embodiment can be easily disassembled by heating. That is, the thermal expandable inorganic material (C) dispersed inside the cured product expands in volume upon heating, so the cured product can be destroyed from the inside, making it easy to disassemble.

[0037] The thermally expandable inorganic material (C) may be, for example, one or more selected from crystalline silica, crystalline aluminum phosphate, and derivatives thereof. The above-mentioned crystalline silica (silicon dioxide; SiO ２ ) has a crystal structure such as quartz type, tridymite type, cristobalite type, etc. Similarly to crystalline silica, crystalline aluminum phosphate also has a crystal structure such as berlinite type, tridalfite type, crystallophile type, etc., which are known to correspond to the crystal structure of silica. Carnegieite is a Si of cristobalite type silica. ４＋ Part of it is Al ３＋ , Na ＋ It is a type of crystalline silica (cristobalite) derivative.

[0038] Both crystalline silica and crystalline aluminum phosphate undergo an α-β transition (phase transition) at a specific temperature in their respective crystal structures, resulting in volume expansion. For example, it is known that cristobalite-type silica undergoes an α-β transition (phase transition) at temperatures between 200°C and 250°C, tridymite-type silica at temperatures between 120°C and 200°C, berlinite-type aluminum phosphate at temperatures between 550°C and 600°C, and crystallite-type aluminum phosphate at temperatures between 300°C and 350°C, resulting in volume expansion. Furthermore, depending on specific conditions such as heating, transitions between crystal structures may occur, resulting in volume expansion. The crystal structure of the thermally expandable inorganic material (C) to be selected can be determined based on factors such as the heating temperature, expansion coefficient, and transition rate required for volume expansion. Furthermore, the thermally expandable inorganic material (C) of this embodiment may be a mixture of materials with different crystal structures.

[0039] In the present embodiment, the thermally expandable inorganic material (C) is preferably cristobalite-type silica or tridymite-type silica from the viewpoint of obtaining easy dismantling properties at low temperatures, and more preferably cristobalite-type silica from the viewpoints of availability, ease of handling, and the like.

[0040] The content of the thermally expandable inorganic material (C) is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and particularly preferably 40% by mass or more, based on the total amount of the resin composition. This can improve the dismantling property by heating. The content of the thermally expandable inorganic material (C) is preferably 98% by mass or less, more preferably 90% by mass or less, and even more preferably 80% by mass or less, based on the total amount of the resin composition. This can improve the moldability of the cured product.

[0041] [Inorganic Filler (D)] The resin composition of the present embodiment may contain an inorganic filler (D) other than the thermally expandable inorganic material (C).

[0042] The inorganic filler (D) is used to increase the mechanical strength and to impart heat resistance, flame retardancy, etc. depending on the intended use of the cured product.

[0043] Specific examples of the inorganic filler (D) include silicates such as talc, calcined clay, uncalcined clay, mica, and glass; oxides such as fused silica, spherical silica, crushed silica, titanium oxide, and boehmite; carbonates such as calcium carbonate, magnesium carbonate, and hydrotalcite; hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide; sulfates or sulfites such as barium sulfate, calcium sulfate, and calcium sulfite; borates such as zinc borate, barium metaborate, aluminum borate, calcium borate, and sodium borate; nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride; titanates such as strontium titanate and barium titanate. These may be used alone or in combination of two or more.

[0044] The average particle size D50 of the inorganic filler (D) is preferably 0.01 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. This can improve strength. On the other hand, the average particle size D50 of the inorganic filler (D) is preferably 75 μm or less, more preferably 40 μm or less, even more preferably 20 μm or less, particularly preferably 10 μm or less, and even more particularly preferably 8 μm or less. Furthermore, by setting the average particle size of the inorganic filler within the above range, the filling property is improved. The average particle size D50 can be the volume-equivalent (cumulative 50%) average particle size measured by a commercially available laser particle size distribution analyzer.

[0045] The inorganic filler (D) may have two or more peaks in the volumetric particle size distribution measured by a laser particle size distribution analyzer. In other words, it is preferable to contain two or more inorganic fillers (D) having different particle sizes. This allows particles with smaller particle sizes to be embedded between particles with larger particle sizes, thereby improving the packing property.

[0046] The content of the inorganic filler (D) is appropriately set depending on the application, but is preferably 1 to 45 mass %, more preferably 10 to 40 mass %, and even more preferably 20 to 35 mass %, based on the total amount of the resin composition. By setting the content of the inorganic filler (D) to the above-mentioned lower limit or more, the storage stability and curability of the cured product can be improved. Furthermore, by setting the content of the inorganic filler (D) to the above-mentioned upper limit or less, easy dismantling and good fluidity of the resin composition can be obtained, making it possible to effectively improve moldability.

[0047] [Coupling Agent] When the resin composition of the present embodiment contains the thermally expandable inorganic material (C) or the inorganic filler (D), it may contain a coupling agent, which can suppress aggregation of the thermally expandable inorganic material (C) and the inorganic filler (D) and achieve good fluidity.

[0048] As the coupling agent, known coupling agents such as various silane compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, and vinylsilane, titanium compounds, aluminum chelates, and aluminum / zirconium compounds can be used.

[0049] More specifically, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl) Silane coupling agents such as γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-(β-aminoethyl)aminopropyldimethoxymethylsilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, and hydrolyzate of 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine;Examples of titanate-based coupling agents include isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate. These may be used alone or in combination of two or more.

[0050] The content of the coupling agent is not particularly limited, but is preferably 0.05% by mass or more and 3% by mass or less, and more preferably 0.1% by mass or more and 2% by mass or less, relative to the total resin composition. By making the content of the coupling agent equal to or greater than the lower limit, the dispersibility of the inorganic filler in the resin composition can be improved. Furthermore, by making the content of the coupling agent equal to or less than the upper limit, the flowability of the resin composition can be improved, and moldability can be improved.

[0051] [Curing Accelerator] The resin composition of the present embodiment may contain a curing accelerator. The curing accelerator typically accelerates the reaction between the thermosetting resin (A) and the curing agent (B).

[0052] Specific examples of the curing accelerator include phosphorus atom-containing compounds such as organic phosphines, tetra-substituted phosphonium compounds, phosphobetaine compounds, adducts of phosphine compounds and quinone compounds, or adducts of phosphonium compounds and silane compounds; amidine compounds such as 1,8-diazabicyclo(5,4,0)undecene-7 and imidazole; nitrogen atom-containing compounds such as tertiary amines, amidinium salts, or ammonium salts, such as benzyldimethylamine; and phenolic compounds such as phenol, bisphenol A, nonylphenol, and 2,3-dihydroxynaphthalene. Examples of the organic phosphines include triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, and 1,2-bis(diphenylphosphino)ethane. These compounds may be used alone or in combination.

[0053] The content of the curing accelerator is appropriately set depending on the application, but is preferably 0.1 to 5 mass %, and more preferably 0.2 to 3 mass %, relative to the total amount of the resin composition. By setting the content of the curing accelerator to be equal to or greater than the above-mentioned lower limit, the resin composition is more likely to be properly cured. On the other hand, by setting the content of the curing accelerator to be equal to or less than the above-mentioned upper limit, the molten state can be prolonged, and the low-viscosity state can be prolonged.

[0054] [Hydroxyl Group-Containing Cyclic Compound] When the resin composition of this embodiment contains a curing accelerator, it may contain a compound in which a hydroxyl group is bonded to each of two or more adjacent carbon atoms constituting an aromatic ring (hereinafter also referred to as a "hydroxyl group-containing cyclic compound"). This makes it possible to suppress reactions during melt-kneading of the resin composition, even when a phosphorus atom-containing curing accelerator that does not have latency is used as the curing accelerator, and a stable resin composition can be obtained. In addition, the hydroxyl group-containing cyclic compound also has the effect of reducing the melt viscosity of the resin composition and improving its flowability.

[0055] The hydroxyl group-containing cyclic compound may be a monocyclic compound represented by the following general formula (5) or a polycyclic compound represented by the following general formula (6). These compounds may have a substituent other than a hydroxyl group.

[0056]

[0057] In general formula (5), one of R15 and R19 is a hydroxyl group, and the other is a hydrogen atom, a hydroxyl group, or a substituent other than a hydroxyl group. R16, R17, and R18 are each a hydrogen atom, a hydroxyl group, or a substituent other than a hydroxyl group.

[0058]

[0059] In general formula (6), one of R20 and R26 is a hydroxyl group, and the other is a hydrogen atom, a hydroxyl group, or a substituent other than a hydroxyl group. R21, R22, R23, R24, and R25 are each a hydrogen atom, a hydroxyl group, or a substituent other than a hydroxyl group.

[0060] Specific examples of monocyclic compounds represented by general formula (5) include catechol, pyrogallol, gallic acid, gallic acid esters, and derivatives thereof. Specific examples of polycyclic compounds represented by general formula (6) include 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and derivatives thereof. Among these, compounds in which a hydroxyl group is bonded to each of two adjacent carbon atoms constituting an aromatic ring are preferred due to ease of control of flowability and curability. Furthermore, when considering volatilization during the kneading process, it is more preferable to use a compound in which the mother nucleus is a naphthalene ring, which has low volatility and high weighing stability. In this case, the hydroxyl group-containing cyclic compound can be, specifically, a compound having a naphthalene ring, such as 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and derivatives thereof. These hydroxyl group-containing cyclic compounds may be used alone or in combination.

[0061] The content of the hydroxyl group-containing cyclic compound is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, and even more preferably 0.05% by mass or more, relative to 100% by mass of the total resin composition. When the content of the hydroxyl group-containing cyclic compound is within the above range, the resin composition can be sufficiently reduced in viscosity and improved in flowability. Furthermore, the content of the hydroxyl group-containing cyclic compound is preferably 2% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.5% by mass or less, relative to 100% by mass of the total resin composition. When the content of the hydroxyl group-containing cyclic compound is within the above range, there is little risk of a decrease in the curability of the resin composition or a decrease in the physical properties of the cured product.

[0062] Furthermore, the resin composition of the present embodiment may further contain various additives, such as a flame retardant; a colorant such as carbon black; a release agent such as natural wax, synthetic wax, higher fatty acid or metal salts thereof, paraffin, or polyethylene oxide; a stress reducing agent such as silicone oil or silicone rubber; an ion scavenger such as hydrotalcites or a hydrous oxide of an element selected from magnesium, aluminum, bismuth, titanium, or zirconium; an adhesion promoter such as thiazoline, diazole, triazole, triazine, or pyrimidine; and an antioxidant.

[0063] The flame retardant may be an inorganic flame retardant. Specific examples of the inorganic flame retardant include aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, phosphazene, and carbon black. One or more of the specific examples may be blended as the flame retardant. Among these, aluminum hydroxide is preferred from the viewpoint of achieving flame retardancy and easy dismantling.

[0064] Furthermore, aluminum hydroxide decomposes due to dehydration when exposed to high temperatures. Therefore, when a structure using the resin composition of the present embodiment containing aluminum hydroxide is heated to 200°C or higher, the structure can be destroyed from the inside due to the dehydration of the aluminum hydroxide, and the structure can be easily disassembled.

[0065] The lower limit of the aluminum hydroxide content is preferably 1% by mass or more relative to the total amount of the resin composition from the viewpoint of obtaining flame retardancy, and is preferably 40% by mass or more, more preferably 50% by mass or more from the viewpoint of obtaining not only flame retardancy but also easy dismantling. On the other hand, the upper limit of the aluminum hydroxide content can be appropriately set depending on the application of the resin composition, and may be, for example, 60% by mass or less.

[0066] Furthermore, from the viewpoint of maintaining good moldability of the resin composition while obtaining the easy dismantling property due to the aluminum hydroxide, the total content of the thermally expandable inorganic material (C), the inorganic filler (D), and the aluminum hydroxide is preferably 60 to 95 mass %, more preferably 70 to 90 mass %, and even more preferably 75 to 85 mass %, based on the total amount of the resin composition.

[0067] [Method for Producing Resin Composition] Next, a method for producing the resin composition of this embodiment will be described. The method for producing the resin composition of this embodiment is not particularly limited, but for example, the thermosetting component and other optional components are mixed using a mixer or the like, and then melt-heated and kneaded at about 90 to 120°C using a heated kneader, heated roll, extruder, or the like. The resulting kneaded mixture is then cooled and pulverized to obtain a powdery or granular resin composition. If necessary, the resin composition may be compressed into tablets after pulverization, or may be formed into a sheet by, for example, vacuum lamination molding or compression molding after pulverization.

[0068] Alternatively, for example, a varnish-like resin composition may be prepared by dissolving, mixing, and stirring the thermosetting component and other optional components in a solvent using various mixers such as ultrasonic dispersion, high-pressure collision dispersion, high-speed rotation dispersion, bead mill dispersion, high-speed shear dispersion, or rotation-revolution dispersion. Specific examples of the solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, toluene, ethyl acetate, heptane, cyclohexane, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve-based solvents, carbitol-based solvents, anisole, and N-methylpyrrolidone. The solvents may be used alone or in combination of two or more.

[0069] 2. Structure The structure of this embodiment includes a cured product of the easily dismantlable resin composition described above. The cured product can be obtained by thermally curing the resin composition of this embodiment at 100 to 200°C for 10 to 900 seconds.

[0070] The structure can be widely applied to, for example, composite materials for transportation equipment such as automobiles, railways, ships, and aircraft; semiconductor devices including semiconductor chips, semiconductor elements, and printed wiring boards; composite materials for factory equipment such as work robots; electronic devices such as electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries; composite materials for civil engineering and construction; and composite materials for sports and recreation. Among these, composite materials for transportation equipment such as automobiles and semiconductor devices are preferred due to the importance of addressing environmental issues. Specific examples of semiconductor devices include those comprising a semiconductor element and an encapsulant that encapsulates the semiconductor element, with the encapsulant being made of a cured product of the resin composition of this embodiment. The encapsulation method is not particularly limited, and known methods can be used. Specifically, rotors, stators, and power modules are preferred. Details of these will be described later.

[0071] <Rotor> The rotor of this embodiment includes a cured product of the easily dismantlable resin composition described above. The cured product is obtained by thermally curing the resin composition of this embodiment at 100 to 200°C for 10 to 900 seconds.

[0072] An example of a rotor according to this embodiment will be described below. Fig. 1 is a plan view showing a rotor 100 according to this embodiment. Fig. 2 is a cross-sectional view showing the rotor 100 shown in Fig. 1. Note that Figs. 1 and 2 are schematic views showing the rotor 100, and the configuration of the rotor 100 according to this embodiment is not limited to that shown in Figs. 1 and 2.

[0073] The rotor 100 includes a rotor core 110, a magnet 120, and a fixing member 130. The rotor core 110 has a hole 150. The magnet 120 is inserted into the hole 150. The fixing member 130 is provided in a space 140 between the hole 150 and the magnet 120. The fixing member 130 is formed using the above-described easily dismantlable resin composition.

[0074] The rotor 100 according to this embodiment constitutes a motor mounted in, for example, an automobile. The motor includes the rotor 100 and a stator disposed around the rotor 100. The stator is composed of a stator core and a coil wound around the stator core. As shown in FIG. 2 , the rotor 100 is attached to a rotating shaft 170. Rotation generated by the rotor 100 is transmitted to the outside via the rotating shaft 170.

[0075] The rotor core 110 has a through hole for inserting the rotating shaft 170. The rotor core 110 is fixed to the rotating shaft 170 inserted into the through hole. The shape of the rotor core 110 is not particularly limited, and may be, for example, circular or polygonal in plan view. As shown in FIG. 2 , the rotor core 110 is formed by stacking a plurality of thin magnetic steel sheets 112. The magnetic steel sheets 112 are made of, for example, iron or an iron alloy. Also, as shown in FIG. 2 , end plates 118 a and 118 b are provided at both axial ends of the rotor core 110. That is, the end plate 118 a is provided above the stacked magnetic steel sheets 112. The end plate 118 b is provided below the stacked magnetic steel sheets 112. The end plates 118 a and 118 b are fixed to the rotating shaft 170 by, for example, welding or the like.

[0076] FIG. 3 is an enlarged cross-sectional view showing the rotor 100 shown in FIG. 3 . As shown in FIG. 3 , crimped portions 160 are formed on the plurality of electromagnetic steel sheets 112. The crimped portions 160 are configured, for example, by protrusions formed on the electromagnetic steel sheets 112. The electromagnetic steel sheets 112 are joined to one another by the crimped portions 160. The end plate 118a is provided with, for example, grooves 116 for avoiding interference with the crimped portions 160 protruding from the electromagnetic steel sheets 112 and the fixing members 130 protruding from the electromagnetic steel sheets 112. The fixing members 130 protruding from the electromagnetic steel sheets 112 are portions formed by hardening of the easily dismantlable resin composition remaining on the electromagnetic steel sheets 112 when the above-mentioned easily dismantlable resin composition is injected into the separation portions 140.

[0077] As shown in FIG. 1 , the rotor core 110 is provided with a plurality of holes 150. The plurality of holes 150 are arranged in the rotor core 110 so as to be point-symmetrical about the axis of the rotating shaft 170. As shown in FIG. 1 , in the rotor 100 of this embodiment, a plurality of hole groups, each consisting of two adjacent holes 150, are arranged along the periphery of the rotating shaft 170. The plurality of hole groups are arranged, for example, to be spaced apart from each other. The two holes 150 that make up one hole group are arranged, for example, in a V-shape in plan view. In this case, the two holes 150 that make up one hole group are arranged so that, for example, their opposing ends are located on the rotating shaft 170 side. Furthermore, the two holes 150 that make up one hole group are arranged, for example, to be spaced apart from each other.

[0078] <Stator> The stator of this embodiment includes a cured product of the easily dismantlable resin composition described above. The cured product is obtained by thermally curing the resin composition of this embodiment at 100 to 200°C for 10 to 900 seconds.

[0079] Fig. 4 is a schematic cross-sectional view perpendicular to the rotational axis direction of the motor 101. Fig. 5 is a schematic cross-sectional view in the rotational axis direction of the motor 101. Fig. 6 is an enlarged view of the periphery of the slot (area X in Fig. 4), and is a schematic cross-sectional view of the portion where the coil 9 protrudes from the end of the slot 8.

[0080] The motor 101 includes a case 1 , and a rotor 2 , a stator 4 , and a coil 9 housed inside the case 1 .

[0081] The case 1 includes a cylindrical portion 1 a and side plates 1 b and 1 c that close both axial ends of the cylindrical portion 1 a. The case 1 can be made of, for example, an aluminum alloy (cast metal), a resin material, or a combination thereof.

[0082] As shown in Fig. 4, the rotor 2 is housed inside the case 1. As shown in Fig. 5, a rotary shaft 3 is attached to the center of the rotor 2 as an output shaft. Both ends of the rotary shaft 3 are supported by the side plate portions 1b and 1c via bearings 3a. This allows the rotor 2 to rotate freely around the rotary shaft 3.

[0083] Permanent magnets 5 are installed inside the rotor 2. Specifically, as shown in Fig. 4, a plurality of (eight in this example) permanent magnets 5 are arranged at equal intervals on the same circumference, with the magnetic poles of adjacent permanent magnets 5 being set to be opposite to each other.

[0084] 5, a cylindrical stator 4 is disposed and fixed to the inner periphery of the cylindrical portion 1a so as to surround the outer periphery of the rotor 2. A minute gap (air gap) is provided between the inner periphery of the stator 4 and the outer periphery of the rotor 2.

[0085] The stator core 41 is formed by stacking a plurality of electromagnetic steel plates in the axial direction and closely fixing them together, and when viewed from the axial end as shown in FIG. 4 , it has an annular yoke portion 6 and a plurality of teeth portions 7 extending from the yoke portion 6 toward the rotor 2 (inner periphery). The plurality of teeth portions 7 are arranged at equal intervals in the circumferential direction. In this example, as shown in FIG. 4 , 24 teeth portions 7 are provided. Slots 8 are provided between each tooth portion 7. The teeth portions 7 are also provided with a thin resin layer 50 formed by wrapping a resin composition around them to cover them.

[0086] The coil 9 is a U-shaped rectangular wire wound so as to straddle the tooth portion 7 and be housed in two spaced-apart slots 8. Here, the coil 9 is housed in a distributed winding in a liner member 20 arranged in the slot 8 ( FIG. 4 ). The coil 9 has a first coil end and a second coil end. The first coil end protrudes to one axial side of the stator core 41. The second coil end protrudes to the other axial side of the stator core 41. In other words, the coil 9 has a pair of coil ends protruding from both axial sides of the stator core 41. The coil 9 is formed using a conductor such as copper, aluminum, or iron, formed into a wire shape.

[0087] The teeth 7 are provided to correspond to the permanent magnets 5 of the rotor 2 described above, and by sequentially exciting each coil 9, the rotor 2 rotates due to attraction and repulsion with the corresponding permanent magnets 5.

[0088] The teeth 7 are tapered, with a larger circumferential width on the outer periphery and a smaller width on the inner periphery. Teeth tips 71 are formed at the inner periphery end of the teeth 7, facing each other along the circumferential direction so as to reduce the width of the slots 8.

[0089] The slots 8 are spaces between adjacent teeth 7, and as shown in Fig. 6, are provided so that wall surfaces 72 of teeth 7 that face each other in the radial direction are parallel to each other. The space between the tooth tips 71 forms an inner peripheral opening of the slot 8. The slot 8 includes a plurality of coils 9 arranged on the outer peripheral side (the yoke portion 6 side) and a resin sealing portion 65 provided on the inner peripheral side (the tooth tip 71 side).

[0090] 6, the resin sealing portion 65 is provided on the inner circumferential side of the slot 8 (the side of the tooth tip 71). The resin sealing portion 65 may be provided by insert molding or may be provided as a separate part. The resin material used for the resin sealing portion 65 is the above-mentioned easily dismantlable resin composition.

[0091] In one embodiment, the resin sealing portion 65 is provided to cover the coil 9 only within the slot 8. In another embodiment, the resin sealing portion 65 is provided to cover the coil 9 within the slot 8 and also to cover one of the pair of coil ends, in other words, to cover only one of the first and second coil ends. In yet another embodiment, the resin sealing portion 65 is provided to cover the coil 9 within the slot 8 and also to cover both of the pair of coil ends, in other words, to cover both the first and second coil ends.

[0092] <Power Module> Fig. 7 is a cross-sectional view showing the configuration of a power module (semiconductor device) 100 according to this embodiment. The power module 100 shown in Fig. 7 includes a semiconductor element 21 mounted on a substrate 30 and a sealing material 51 that seals the semiconductor element 21.

[0093] A lead frame is used as the substrate 30. The lead frame is made of metal, for example, copper.

[0094] The semiconductor element 21 is a power semiconductor element, and preferably is a power semiconductor element that satisfies any one of the following conditions (a) to (d): (a) a semiconductor element with a power consumption of 2.0 W or more; (b) a semiconductor element made of SiC, GaN, or Ga; ２ O ３ and diamond. (c) A semiconductor element having a voltage of 1.0 V or more. (d) A semiconductor element having a power density of 10 W / cm ３ The above semiconductor elements

[0095] The power consumption of the semiconductor element 21 may be, for example, 2.0 W or more, preferably 3.0 W or more, as specified in the above-mentioned condition (a), or may be, for example, 4.0 W or less. i The voltage of the semiconductor element 21 may be, for example, 1.0 V or more, preferably 3.0 V or more, as specified in the above-mentioned condition (c), or may be, for example, 5.0 V or more. The voltage of the semiconductor element 21 may be, for example, 100 V or less. i The power density of the semiconductor element 21 may be, for example, 10 W / cm2, as specified in the above-mentioned condition (d). ３or more, preferably 20 W / cm ３ or more, and for example, 30 W / cm ３ The power density of the semiconductor element 21 may be, for example, 200 W / cm ３ The semiconductor element 21 may be capable of operating in a high temperature environment of, for example, 200° C. or higher, preferably 260° C. or higher.

[0096] The semiconductor element 21 is preferably a power semiconductor element provided on the substrate 30, and includes one or more electronic components selected from the group consisting of a rectifier diode, a power transistor, a power MOSFET, an insulated gate bipolar transistor (IGBT), a thyristor, a gate turn-off thyristor (GTO), and a triac.

[0097] The semiconductor element 21 is mounted on, for example, a die pad 32 of the substrate 30 and is electrically connected to outer leads 34 via wires 40 .

[0098] The encapsulant 51 encapsulates the semiconductor element 21 so as to cover the other surface of the semiconductor element 21 opposite to the surface facing the substrate 30. The encapsulant 51 of this embodiment is made of a cured product of the above-mentioned easily dismantlable resin composition. The encapsulant 51 can be formed, for example, by encapsulating the easily dismantlable resin composition using a known method such as transfer molding or compression molding.

[0099] 3. Dismantling Method The method for dismantling a structure according to the present embodiment includes the step of heating the structure to 200° C. or higher to dismantle the cured product of the easily dismantlable resin composition. Because the cured product can be dismantled by heating, no machinery or tools are required to destroy the cured product, and contamination, corrosion, and the like that occur when chemicals or the like are used can be suppressed.

[0100] The heating temperature can be set appropriately depending on the type of thermally expandable inorganic material (C), etc., but is preferably 250°C or higher, more preferably 300°C or higher, from the viewpoint of improving ease of dismantling. The temperature may be further increased depending on the use of the structure and from the viewpoint of shortening the time until dismantling. Specifically, when the structure is a rotor, the temperature may be 350°C or higher to accommodate demagnetization of the magnet. On the other hand, the heating temperature is preferably 600°C or lower, more preferably 500°C or lower, from the viewpoint of reducing the thermal load and environmental load on the structure.

[0101] The heating method is not particularly limited, and any known method can be used.

[0102] 4. Recycling Method The recycling of this embodiment is a method for recycling materials constituting the above-described structure, and includes a step of heating the structure to 200°C or higher to dismantle the cured product of the easily dismantlable resin composition, and a step of recovering the materials from the structure. This allows the materials used in the structure to be reused. The step of dismantling the cured product is the same as the method described in the dismantling method above.

[0103] Furthermore, the method for recovering materials from a structure is not particularly limited as long as it does not degrade the quality of the material. For example, a method may be used in which the structure is destroyed together with the hardened material that has become brittle due to dismantling, and the material is recovered.

[0104] When the structure is a rotor, the material recovered from the rotor is not particularly limited as long as it is heat-resistant, and examples thereof include metals (electromagnetic steel sheets) and permanent magnets.

[0105] When the structure is a stator, the material recovered from the stator is not particularly limited as long as it is heat-resistant, and examples thereof include coils and metals (electromagnetic steel sheets).

[0106] When the structure is a power module, the material recovered from the power module is not particularly limited as long as it is heat-resistant, and examples thereof include metallic lead frames.

[0107] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted.

[0108] Next, the present invention will be described in detail with reference to examples, but the content of the present invention is not limited to the examples.

[0109] <Preparation of Resin Compositions> Using the raw materials shown below, each component was mixed at the solid content ratio shown in Table 1 to obtain a mixture. Mixing was performed at room temperature using a Henschel mixer. The resulting mixture was then roll-kneaded at 90 to 120°C to obtain a kneaded product. The resulting kneaded product was cooled and then pulverized to obtain each resin composition. [Raw Materials] (Thermosetting Resin (A)) Epoxy Resin 1: Biphenylene Skeleton-Containing Phenol Aralkyl Epoxy Resin (Nippon Kayaku, NC3000)

[0110] (Curing agent (B)) Curing agent 1: biphenylene skeleton-containing phenol aralkyl resin (MEH-7851SS, manufactured by Meiwa Chemical Industry Co., Ltd.) Curing agent 2: biphenylene skeleton-containing phenol aralkyl resin (GPH-65, manufactured by Nippon Kayaku Co., Ltd.)

[0111] (Thermal Expandable Inorganic Material (C)) Thermal Expandable Inorganic Material 1: Cristobalite-type silica (Cristobalite manufactured by Micron Corporation)

[0112] (Inorganic filler (D)) Inorganic filler 1: fused spherical silica TS-6026, Micron (average particle size D50: 9 μm) Inorganic filler 2: fused spherical silica SC-2500-SQ, Admatechs (average particle size D50: 0.6 μm) Inorganic filler 3: fused spherical silica SC-5500-SQ, Admatechs (average particle size D50: 1.6 μm)

[0113] (Curing accelerator) Curing accelerator 1: Tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenyl silicate

[0114] (Others) Colorant: Carbon black (Carbon #5, manufactured by Mitsubishi Chemical Corporation) Coupling agent: N-phenyl-3-aminopropyltrimethoxysilane (CF-4083, manufactured by Dow Corning Toray Co., Ltd.) Mold release agent: Synthetic wax (WE-4, manufactured by Clariant Chemicals Co., Ltd.) Stress reduction agent: Silicone oil (FZ-3730, manufactured by Dow Corning Toray Co., Ltd.) Ion scavenger: Magnesium hydroxide carbonate hydrate (DHT-4H, manufactured by Kyowa Chemical Industry Co., Ltd.) Flame retardant: Aluminum hydroxide (CL-303, manufactured by Sumitomo Chemical Co., Ltd.)

[0115] <Evaluation and Measurement> (1) Adhesion Strength Each of the obtained easily dismantlable resin compositions was molded onto a copper substrate ("EFTEC64-T" copper plate manufactured by Furukawa Electric Co., Ltd., which was Cu strike-plated) under conditions of 175°C, 6.9 MPa, and 120 seconds, and then post-cured at 175°C for 4 hours to obtain a test specimen. Using the test specimen, the shear adhesion to the copper substrate was measured at room temperature at a rate of 300 μm / sec, and the adhesion strength [N / mm ２ ] to S1 [N / mm ２ Furthermore, the test piece was heated at 300° C. for 30 minutes, and then the shear adhesion to the copper substrate was measured at room temperature at a rate of 300 μm / sec. ２ ] to S2 [N / mm ２ The results are shown in Table 1.

[0116] (2) TMA Measurement (Glass Transition Temperature, Linear Expansion Coefficient) Each of the obtained easily dismantlable resin compositions was molded onto a copper substrate under conditions of 175°C, 10 MPa, and 120 seconds, and then post-cured at 175°C for 4 hours to obtain a test specimen. Using the test specimen, measurements were performed using a thermomechanical analyzer (Seiko Instruments Inc., TMA / SS6000) at a measurement temperature range of 25°C to 320°C and a heating rate of 5°C / min. From the measurement results, the glass transition temperature Tg (°C) was calculated. α1 was the linear expansion coefficient at 40°C to 80°C, α2 was the linear expansion coefficient at 190°C to 230°C, and α3 was the linear expansion coefficient at 250°C to 260°C.

[0117] (3) Ease of Dismantling Each of the obtained easy-to-dismantle resin compositions was molded onto a nickel plate under conditions of 175°C, 6.9 MPa, and 120 seconds, and then post-cured at 175°C for 4 hours to obtain test specimens. The test specimens were then heated at 300°C for 30 minutes, cooled to room temperature, and evaluated for ease of dismantling according to the following criteria. (Criteria) ◯: The cured product of the test specimen peeled off from the nickel plate ×: The cured product of the test specimen did not peel off from the nickel plate

[0118]

[0119] This application claims priority based on Japanese Patent Application No. 2023-040608, filed March 15, 2023, the disclosure of which is incorporated herein in its entirety.

[0120] REFERENCE SIGNS LIST 1 case 1a cylindrical portion 1b side plate portion 2 rotor 3 rotating shaft 3a bearing 4 stator 5 permanent magnet 6 yoke portion 7 teeth portion 8 slot 9 coil 20 liner member 21 semiconductor element 30 substrate 32 die pad 34 outer lead 40 wire 41 stator core 50 resin layer 51 sealing material 65 resin sealing portion 71 teeth portion tip 72 wall surface 100 rotor 200 power module 101 motor 110 rotor core 112 electromagnetic steel sheet 116 groove portion 118a end plate 118b end plate 120 magnet 130 fixing member 140 separation portion 150 hole portion 160 crimped portion 170 rotating shaft

Claims

1. An easily dismantlable resin composition containing a thermosetting resin, The adhesion strength ratio (S2 / S1) measured by the following procedure is 0.30 or less, An easily dismantlable resin composition in the form of a powder, granule, or tablet. [procedure] The easily dismantlable resin composition was molded onto a copper substrate under conditions of 175° C., 6.9 MPa, and 120 seconds, and then post-cured at 175° C. for 4 hours to obtain a test specimen. The shear adhesion between the test piece and the copper substrate was measured at room temperature at a speed of 300 μm / sec. The adhesion strength [N / mm ２ ] to S1 [N / mm ２ ] Furthermore, the test piece was heated at 300° C. for 30 minutes, and then the shear adhesion to the copper substrate was measured at room temperature at a speed of 300 μm / sec. The adhesion strength [N / mm ２ ] to S2 [N / mm ２ ]

2. The easily dismantlable resin composition according to claim 1, The adhesion strength (S2) measured by the above procedure is 3.0 N / mm ２ The following is an easily dismantlable resin composition.

3. The easily dismantlable resin composition according to claim 1 or 2, The easily dismantlable resin composition is molded under conditions of 175°C, 6.9 MPa, and 120 seconds, and then post-cured at 175°C for 4 hours, resulting in a cured product having a linear expansion coefficient α2 of 46 ppm / °C or more in the temperature range of 190°C to 230°C.

4. The easily dismantlable resin composition according to claim 1 or 2, The easily dismantlable resin composition is molded under conditions of 175°C, 6.9 MPa, and 120 seconds, and then post-cured at 175°C for 4 hours, and the cured product has a linear expansion coefficient α3 in the temperature range of 250 to 260°C of 60 ppm / °C or more.

5. The easily dismantlable resin composition according to claim 1 or 2, The easily dismantlable resin composition, wherein the thermosetting resin comprises one or more resins selected from the group consisting of epoxy resins, phenoxy resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, cyanate resins, bismaleimide resins, and acrylic resins.

6. The easily dismantlable resin composition according to claim 1 or 2, The easily dismantlable resin composition further comprises a curing agent.

7. The easily dismantlable resin composition according to claim 6, The easily dismantlable resin composition, wherein the curing agent comprises a phenol-based curing agent.

8. The easily dismantlable resin composition according to claim 1 or 2, The easily dismantlable resin composition further comprises a thermally expandable inorganic material, and the content of the thermally expandable inorganic material is 5 to 98 mass% based on the total amount of the easily dismantlable resin composition.

9. The easily dismantlable resin composition according to claim 8, The easily dismantlable resin composition, wherein the thermally expandable inorganic material comprises one or more selected from the group consisting of crystalline silica, crystalline aluminum phosphate, and derivatives thereof.

10. The easily dismantlable resin composition according to claim 8, The easily dismantlable resin composition includes one or more thermally expandable inorganic materials selected from the group consisting of quartz-type silica, cristobalite-type silica, tridymite-type silica, berlinite-type aluminum phosphate, tridalphite-type aluminum phosphate, crystallite-type aluminum phosphate, and carnegieite.

11. The easily dismantlable resin composition according to claim 1 or 2, An easily dismantlable resin composition further comprising aluminum hydroxide.

12. The easily dismantlable resin composition according to claim 11, The content of the aluminum hydroxide is 1% by mass or more based on the total amount of the easily dismantlable resin composition.

13. The easily dismantlable resin composition according to claim 1 or 2, The composition includes one or more selected from a thermally expandable inorganic material, an inorganic filler, and aluminum hydroxide; The easily dismantlable resin composition, wherein a total content of the thermally expandable inorganic material, the inorganic filler, and the aluminum hydroxide is 60 mass% or more with respect to a total amount of the easily dismantlable resin composition.

14. A structure comprising a cured product of the easily dismantlable resin composition according to claim 1 or 2.

15. A method for dismantling a structure according to claim 14, comprising the steps of: A method for dismantling a structure, comprising: heating the structure to 200° C. or higher to dismantle the cured product of the easily dismantlable resin composition.

16. A method for recycling materials constituting the structure according to claim 14, comprising the steps of: A step of heating the structure to 200° C. or higher to dismantle the cured product of the easily dismantlable resin composition; and recovering said material from said structure.

17. The easily dismantlable resin composition according to claim 1 or 2, a rotor core fixed to the rotating shaft and having a plurality of holes disposed along a periphery of the rotating shaft; A magnet inserted into the hole; The easily dismantlable resin composition is used for forming a fixing member of a rotor including the fixing member provided in a portion separated from the hole and the magnet.

18. A rotor comprising the cured product of the easily dismantlable resin composition according to claim 17 as the fixing member.

19. 20. A rotor dismantling method according to claim 18, comprising the steps of: A rotor dismantling method comprising the step of heating the rotor to 200° C. or higher to dismantle the cured product of the easily dismantlable resin composition.

20. A method for recycling materials constituting the rotor according to claim 18, comprising the steps of: Heating the rotor to 200° C. or higher to dismantle the cured product of the easily dismantlable resin composition; and recovering said material from said rotor.

21. 21. The recycling method according to claim 20, The material is at least one selected from the group consisting of the magnet and an electromagnetic steel sheet inserted into the hole.

22. The easily dismantlable resin composition according to claim 1 or 2, An easily dismantlable resin composition used for forming a sealing member of a stator having a stator core having a plurality of teeth and a plurality of slots formed alternately in the circumferential direction, a coil wound around and housed in the slot, the coil having a pair of coil ends protruding from the stator core on both axial sides, and a sealing member provided within the slot to cover the coil.

23. A stator comprising the cured product of the easily dismantlable resin composition according to claim 22 as the sealing member.

24. A method for dismantling a stator according to claim 23, comprising the steps of: A method for dismantling a stator, comprising: heating the stator to 200° C. or higher to dismantle the cured product of the easily dismantlable resin composition.

25. A method for recycling materials constituting a stator according to claim 23, comprising the steps of: Heating the stator to 200° C. or higher to dismantle the cured product of the easily dismantlable resin composition; and recovering said material from said stator.

26. 26. The recycling method according to claim 25, The recycling method, wherein the material is at least one selected from the group consisting of coils and electromagnetic steel sheets.

27. The easily dismantlable resin composition according to claim 1 or 2, An easily dismantlable resin composition used to form a sealing member of a power module including a wiring board, a plurality of electronic components mounted on the wiring board, and a sealing member that seals the electronic components.

28. A power module comprising a cured product of the easily dismantlable resin composition according to claim 27 as the sealing member.

29. A method for dismantling a power module according to claim 28, comprising the steps of: A method for dismantling a power module, comprising: heating the power module to 200°C or higher to dismantle the cured product of the easily dismantlable resin composition.

30. A method for recycling materials constituting the power module according to claim 28, comprising the steps of: A step of heating the power module to 200° C. or more to dismantle the cured product of the easily dismantlable resin composition; and recovering the material from the power module.

31. 31. The recycling method according to claim 30, The recycling method wherein the material is a metal lead frame.