Easily decomposable resin composition, structure comprising a cured product of the easily decomposable resin composition, method for decomposing the structure, and method for recycling the material constituting the 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

Technical Field

[0001] The present invention relates to a readily disassemblable resin composition, a structure including a cured product of the readily disassemblable resin composition, a method for disassembling the structure, and a method for recycling materials constituting the structure.

Background Art

[0002] In recent years, in the automotive industry, in order to respond to global climate change and achieve a carbon-neutral society, the electrification of vehicles has been actively promoted. Many of the motors in these electric vehicles use neodymium magnets, which contain rare elements called rare earths such as neodymium and dysprosium. On the other hand, rare earths are a concern due to uneven distribution of resources and price fluctuations due to supply-demand imbalances, and also involve a burden on the ecosystem during mining and smelting. Therefore, reducing their usage has become an issue. Therefore, in the automotive industry, technologies related to the reuse of rare earths are attracting attention as an effective utilization of resources.

[0003] For example, it is known to remove and disassemble and reuse magnets from motors that could not be installed in automobiles that did not meet the shipping standards. Also, for example, Patent Document 1 discloses a method of heating a rotor to a temperature higher than either the Curie temperature or the ashing temperature of the adhesive, and then applying vibrations to the metal plate on the end face of the rotor such that the metal plate resonates, thereby detaching the adhesive and the magnet from the hole.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the prior art as disclosed in Patent Document 1, in the process of extracting rare earth from the magnet of the motor, manual disassembly and extraction of the magnet occur, so there is room for improvement in terms of simplification of the process and reduction of recycling costs. Also, when trying to extract the magnet by heating at a high temperature (about 600 to 700 °C) to ash the adhesive, if the thermal energy is not clean, carbon dioxide will be generated.

[0006] As a result of intensive studies to solve such problems, the present inventor has found that it is effective for the cured product of the resin composition used for fixing the rotor etc. to have a predetermined structure and predetermined physical properties. Specifically, among the cured products obtained by curing the resin composition, it was found that there are differences in disassemblability by controlling the adhesion to copper, and a new index was devised.

Means for Solving the Problems

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

[0008] [1] An easily disassemblable resin composition containing a thermosetting resin, An easily disassemblable resin composition in which the adhesion strength ratio (S2 / S1) measured by the following procedure is 0.30 or less. [Procedure] The easily disassemblable resin composition is molded on a copper substrate under the conditions of 175 °C, 6.9 MPa, and 120 seconds, and a test piece further post-cured at 175 °C for 4 hours is obtained. Using the test piece, the adhesion strength [N / mm 2 when measuring the shear adhesion to the copper substrate at a speed of 300 μm / sec at room temperature is taken as S1 [N / mm 2 . Furthermore, after heating the test piece at 300 °C for 30 minutes, the adhesion strength [N / mm 2 when measuring the shear adhesion to the copper substrate at a speed of 300 μm / sec at room temperature is taken as S2 [N / mm 2 . [2] The easily decomposable resin composition according to [1], wherein the adhesion strength (S2) measured by the above procedure is 3.0 N / mm 2 or less. The easily decomposable resin composition. [3] The easily decomposable resin composition according to [1] or [2], wherein the linear expansion coefficient α2 in the temperature range of 190°C to 230°C of the cured product obtained by molding the easily decomposable resin composition under the conditions of 175°C, 6.9 MPa, and 120 seconds and further performing post-curing at 175°C for 4 hours is 46 ppm / °C or more. The easily decomposable resin composition. [4] The easily decomposable resin composition according to any one of [1] to [3], wherein the linear expansion coefficient α3 in the temperature range of 250 to 260°C of the cured product obtained by molding the easily decomposable resin composition under the conditions of 175°C, 6.9 MPa, and 120 seconds and further performing post-curing at 175°C for 4 hours is 60 ppm / °C or more. The easily decomposable resin composition. [5] The easily decomposable resin composition according to any one of [1] to [4], wherein the thermosetting resin contains 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. The easily decomposable resin composition. [6] The easily decomposable resin composition according to any one of [1] to [5], further comprising a curing agent. The easily decomposable resin composition. [7] The easily decomposable resin composition according to [6], wherein the curing agent contains a phenolic curing agent. The easily decomposable resin composition. [8] The easily decomposable resin composition according to any one of [1] to [7], further comprising a thermally expandable inorganic material, and the content of the thermally expandable inorganic material is 5 to 98% by mass based on the total amount of the easily decomposable resin composition. The easily decomposable resin composition. [9] The easily decomposable resin composition according to [8], The easily decomposable resin composition, wherein the thermally expandable inorganic material contains one or more selected from crystalline silica, crystalline aluminum phosphate, and derivatives thereof.

[10] The easily decomposable resin composition according to [8] or [9], The easily decomposable resin composition, wherein the thermally expandable inorganic material contains one or more selected from quartz-type silica, cristobalite-type silica, tridymite-type silica, berlinite-type aluminum phosphate, tridalite-type aluminum phosphate, crystalite-type aluminum phosphate, and carnegieite.

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

[10] , The easily decomposable resin composition further containing aluminum hydroxide.

[12] The easily decomposable resin composition according to

[11] , The easily decomposable resin composition, wherein the content of the aluminum hydroxide is 1% by mass or more based on the total amount of the easily decomposable resin composition.

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

[12] , The easily decomposable resin composition containing one or more selected from a thermally expandable inorganic material, an inorganic filler, and aluminum hydroxide, The easily decomposable resin composition, wherein the total content of the thermally expandable inorganic material, the inorganic filler, and the aluminum hydroxide is 60% by mass or more based on the total amount of the easily decomposable resin composition.

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

[13] , The easily decomposable resin composition in a powdery, granular, or tablet form.

[15] The structure including a cured product of the easily decomposable resin composition according to any one of [1] to

[14] .

[16] The method for decomposing the structure according to

[15] , The method for decomposing the structure including a step of heating the structure to 200°C or higher to decompose the cured product of the easily decomposable resin composition.

[17] The recycling method for the material constituting the structure according to

[15] , A step of heating the structure to 200 °C or higher to disintegrate the cured product of the easily disintegratable resin composition; A step of recovering the material from the structure, the recycling method comprising the steps.

[18] An easily disintegratable resin composition according to any one of [1] to

[14] , A rotor core fixed to a rotating shaft and provided with a plurality of holes arranged along a peripheral portion of the rotating shaft; Magnets inserted into the holes; An easily disintegratable resin composition used for forming the fixing member among rotors including a fixing member provided in a separating portion between the holes and the magnets.

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

[18] as the fixing member.

[20] A method for disassembling a rotor according to

[19] , The method for disassembling a rotor includes a step of heating the rotor to 200 °C or higher to disintegrate the cured product of the easily disintegratable resin composition.

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

[19] , The recycling method includes a step of heating the rotor to 200 °C or higher to disintegrate the cured product of the easily disintegratable resin composition, and A step of recovering the material from the rotor.

[22] The recycling method according to

[21] , The recycling method, wherein the material is one or more selected from the magnets inserted into the holes and electromagnetic steel sheets.

[23] An easily disintegratable resin composition according to any one of [1] to

[14] , A stator core having a plurality of teeth portions and a plurality of slots formed alternately in the circumferential direction, a coil wound around the slots and housed in the slots and having a pair of coil ends protruding from both axial sides of the stator core, and a sealing member provided to cover the coil in the slots, the easily disintegratable resin composition being used for forming the sealing member among stators.

[24] A stator comprising, as the sealing member, a cured product of the easily disassembled resin composition described in

[23] .

[25] A method for disassembling the stator described in

[24] , The method for disassembling a stator includes a step of heating the stator to 200°C or higher to disassemble the cured product of the easily disassembled resin composition.

[26] A recycling method for the materials constituting the stator described in

[24] , The recycling method includes a step of heating the stator to 200°C or higher to disassemble the cured product of the easily disassembled resin composition, and a step of recovering the materials from the stator.

[27] The recycling method described in

[26] , wherein the materials are one or more selected from a coil and an electromagnetic steel sheet.

[28] An easily disassembled resin composition according to any one of [1] to

[14] , which is used to form the sealing member among a power module including a wiring board, a plurality of electronic components mounted on the wiring board, and a sealing member for sealing the electronic components.

[29] A power module comprising, as the sealing member, a cured product of the easily disassembled resin composition described in

[28] .

[30] A method for disassembling the power module described in

[29] , The method for disassembling a power module includes a step of heating the power module to 200°C or higher to disassemble the cured product of the easily disassembled resin composition.

[31] A recycling method for the materials constituting the power module described in

[29] , The recycling method includes a step of heating the power module to 200°C or higher to disassemble the cured product of the easily disassembled resin composition, and a step of recovering the materials from the power module.

[32] The recycling method described in

[31] , wherein the materials are a metal lead frame.

Advantages of the Invention

[0009] According to the present invention, since the cured product of the easily decomposable resin composition containing a thermosetting resin can be easily decomposed, the recyclability of the material constituting the structure including the cured product of the easily decomposable resin composition can be improved.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0011] In this specification, the notation "a to b" in the description of a numerical range represents a to b unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% or more and 5 mass% or less". Further, the lower limit value and the upper limit value of the numerical range can be arbitrarily combined with the lower limit value and the upper limit value of other numerical ranges, respectively.

[0012] Each component and material exemplified in this specification may be used alone or in combination of two or more unless otherwise specified.

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

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

[0015] [Procedure] A test piece is obtained by molding the easily disassemblable resin composition on a copper substrate under the conditions of 175°C, 6.9 MPa, and 120 seconds, and further performing post-curing at 175°C for 4 hours. Using the test piece, the adhesion strength [N / mm 2 when measuring the shear adhesion to the copper substrate at a speed of 300 μm / second at room temperature is taken as S1 [N / mm 2 . Furthermore, after heating the test piece at 300°C for 30 minutes, the adhesion strength [N / mm 2 when measuring the shear adhesion to the copper substrate at a speed of 300 μm / second at room temperature is taken as S2 [N / mm 2 .

[0016] That is, in the easily disassemblable resin composition of this embodiment, since the adhesion of the cured product to other materials decreases due to heating, it is considered that peeling, separation, etc. become easy and the cured product is easily disassembled.

[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, still more preferably 0.15 or less, and even more 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 adhesion strength (S2) measured by the above procedure is preferably 3.0 N / mm 2 or less from the viewpoint of making disassembly easier, more preferably 2.0 N / mm 2 or less, still more preferably 1.0 N / mm 2 or less, and even more preferably 0.5 N / mm 2 or less. The lower limit of the adhesion strength (S2) is not particularly limited, and it may already be peeled off from the copper substrate even before the measurement of the adhesion strength. That is, it is intended that the cured product of the test piece and the copper substrate be peeled off 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) also becomes 0.

[0019] The adhesion strength (S1) measured by the above procedure is preferably 8 N / mm 2 or more, more preferably 9 N / mm 2 or more, still more preferably 10 N / mm 2 or more, and even more preferably 12 N / mm 2 or more, from the viewpoint of obtaining good mechanical strength of the cured product. On the other hand, the upper limit of the adhesion strength (S1) is not particularly limited and is appropriately set according to the application. For example, it may be 50 N / mm 2 or less.

[0020] Also, the linear expansion coefficient α2 in the temperature range of 190 °C to 230 °C of the cured product obtained by molding the easily decomposable resin composition under the conditions of 175 °C, 6.9 MPa, and 120 seconds and further performing post-curing at 175 °C for 4 hours is preferably 46 ppm / °C or more, more preferably 50 ppm / °C or more, and still more preferably 55 ppm / °C or more. Thereby, the cured product and other materials are likely to be peeled off, separated, etc., and the easy decomposability can be improved.

[0021] Also, the linear expansion coefficient α3 in the temperature range of 250 °C to 260 °C of the cured product obtained by molding the easily decomposable resin composition under the conditions of 175 °C, 6.9 MPa, and 120 seconds and further performing post-curing at 175 °C for 4 hours is preferably 80 ppm / °C or more, more preferably 100 ppm / °C or more, and still more preferably 200 ppm / °C or more. Thereby, the cured product and other materials are likely to be peeled off, separated, etc., and the easy decomposability can be improved.

[0022] In this embodiment, "easy disassembly" means that cracks can be made in the cured product obtained by thermosetting the easy-disassembly resin composition of this embodiment by a simple method, or the cured product can be easily crushed, separated, etc., so as to be disassembled. For example, easy disassembly can be obtained by easily peeling off the cured product of the easy-disassembly resin composition of this embodiment and the materials (sealed materials, etc.) in the cured product. That is, the cured product can be disassembled without applying excessive external stress that also loads the materials contained in the cured product, or without performing chemical treatment using chemicals or the like.

[0023] The easy-disassembly resin composition having adhesion strength in this embodiment can be realized by selecting various components constituting the easy-disassembly resin composition and adjusting their contents. Specifically, for example, control of the curability of the thermosetting resin (A) and the curing agent (B), selection of the thermally expandable inorganic material (C) described later, adjustment of the contents of the thermally expandable inorganic material (C), the inorganic filler (D), and the flame retardant, etc. can be mentioned.

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

[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 phenol 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. For these thermosetting resins, monomers, oligomers, and polymers in general having two or more reactive functional groups in one molecule can be used, and their molecular weights and molecular structures are not particularly limited.

[0026] For the above epoxy resins, monomers, oligomers, and polymers in general having two or more epoxy groups in one molecule can be used, and their molecular weights and molecular structures are not particularly limited. Epoxy resins specifically 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 type epoxy resins such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, diamino diphenylmethane type glycidylamine, and aminophenol type glycidylamine; hydroquinone type epoxy resins; biphenyl type epoxy resins; stilbene type epoxy resins; triphenol methane type epoxy resins; triphenol propane type epoxy resins; alkyl-modified triphenol 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, or aliphatic epoxy resins such as alicyclic epoxies such as vinylcyclohexene dioxide, dicyclopentadiene dioxide, and Alicyclic diepoxy-adipate. One or more selected from these may be mentioned. Among them, 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 with respect to the total amount of the resin composition. By setting the content of the thermosetting resin (A) to be not less than the above lower limit value, the fluidity and moldability of the resin composition can be more effectively improved. Also, by setting the content of the thermosetting resin (A) to be not more than the above upper limit value, 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 according to the type of the 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, etc.

[0029] Specifically, the curing agent (B) includes phenolic curing agents, amines, polyoxystyrenes such as polyp paraoxystyrene, alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), acid anhydrides such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), and benzophenonetetracarboxylic acid (BTDA), polymercaptan compounds such as polysulfide, thioester, and thioether, isocyanate compounds such as isocyanate prepolymer and blocked isocyanate, and organic acids such as carboxylic acid-containing polyester resins.

[0030] Specific examples of the phenolic curing agent include novolak-type phenolic resins such as phenolic novolak resin, cresol novolak resin, naphthol novolak resin, aminotriazine novolak resin, novolak resin, and triphenylmethane-type phenolic novolak resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl-type resins such as phenolic aralkyl resin having a phenylene skeleton and / or biphenylene skeleton and naphthol aralkyl resin 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, it is preferably that the hydroxyl equivalent of the phenolic resin-based curing agent is, for example, 90 g / eq or more and 250 g / eq or less.

[0031] As the above amines, specifically, for example, aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylenediamine (MXDA), aromatic polyamines such as diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenylsulfone (DDS), and polyamine compounds containing dicyandiamide (DICY), organic acid dihydrazide, etc.; alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA), and acid anhydrides such as aromatic acid anhydrides like trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), and benzophenonetetracarboxylic acid (BTDA), etc. One or more selected from among these may be mentioned.

[0032] In the present embodiment, when an epoxy resin is used as the thermosetting resin (A), it is preferable to combine a phenolic 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, with respect to 100 parts by mass of the thermosetting resin (A).

[0034] Also, the contents of the thermosetting resin (A) and the curing agent (B) are appropriately set according to the thermosetting resin (A) and the curing agent (B). For example, for the phenolic curing agent as the curing agent (B) and the epoxy resin as the thermosetting resin (A), the equivalent ratio (EP) / (OH) of the epoxy group number (EP) in the total thermosetting resin and the phenolic hydroxyl group number (OH) of the total phenolic resin is preferably adjusted to be 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 resin composition of the present embodiment obtained can be made good.

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

[0036] [Thermally expandable inorganic material (C)] The thermally expandable inorganic material (C) refers to a material that undergoes a phase transformation upon heating, resulting in volume expansion. By using the thermally expandable inorganic material (C), the cured product of the resin composition of the present embodiment can be easily disassembled by heating. That is, since the thermally expandable inorganic material (C) dispersed inside the cured product expands in volume upon heating, the cured product can be broken from the inside, and the cured product can be easily disassembled.

[0037] Examples of the thermally expandable inorganic material (C) include one or more selected from crystalline silica, crystalline aluminum phosphate, and derivatives thereof. The above-mentioned crystalline silica (silicon dioxide; SiO2) has a crystal structure such as quartz type, tridymite type, cristobalite type, etc. Also, crystalline aluminum phosphate, like crystalline silica, is known to have a crystal structure such as berlinite type, tridalfite type, crystalfite type, etc., and each corresponds to the crystal structure of silica. Carnegieite is a type of crystalline silica (cristobalite) derivative in which a part of Si 4+ is replaced by Al 3+ and Na + and is a kind of crystalline silica (cristobalite) derivative.

[0038] Both crystalline silica and crystalline aluminum phosphate undergo an α-β transition (phase dislocation) at a specific temperature in each crystal structure, causing volume expansion. For example, cristobalite-type silica undergoes an α-β transition (phase transition) and volume expansion in the temperature range of 200°C to 250°C, tridymite-type silica in the temperature range of 120°C to 200°C, berlinite-type aluminum phosphate at 550 - 600°C, and crystalfite-type aluminum phosphate at 300 - 350°C. Also, under predetermined conditions such as heating, there may be cases where it can transfer between crystal structures and cause volume expansion. Which thermally expandable inorganic material (C) with a certain crystal structure to select can be determined from aspects such as the heating temperature, expansion rate, and transition rate required for volume expansion. Also, the thermally expandable inorganic material (C) of the present embodiment may be a mixture of those with different crystal structures.

[0039] In this embodiment, from the viewpoint of obtaining easy disintegration at low temperatures, the thermally expandable inorganic material (C) is preferably cristobalite-type silica or tridymite-type silica, and more preferably cristobalite-type silica from the viewpoints of availability, handleability, etc.

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

[0041] [Inorganic filler (D)] The resin composition of this embodiment may contain an inorganic filler (D) excluding the above-mentioned thermally expandable inorganic material (C).

[0042] The inorganic filler (D) is used to increase the mechanical strength, impart heat resistance, flame retardancy, etc., according to the 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 diameter 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. Thereby, the strength can be improved. On the other hand, the average particle diameter 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, even more preferably 10 μm or less, and even more preferably 8 μm or less. Moreover, by setting the average particle diameter of the inorganic filler within the above range, the fillability is improved. The average particle diameter D50 can be the volume-converted (cumulative 50%) average particle diameter measured by a commercially available laser particle size distribution analyzer.

[0045] Also, in the volume-based particle size distribution of the inorganic filler (D) measured by a laser particle size distribution analyzer, it may have two or more peaks. In other words, it is preferable to contain two or more kinds of inorganic fillers (D) having different particle diameters. Thereby, particles with small particle diameters can enter between particles with large particle diameters, making it easier to improve the fillability.

[0046] The content of the inorganic filler (D) is appropriately set according to the application, but is preferably 1 to 45% by mass, more preferably 10 to 40% by mass, and even more preferably 20 to 35% by mass with respect to the total amount of the resin composition. By setting the content of the inorganic filler (D) to be equal to or higher than the above lower limit value, the storage stability and curability of the cured product can be improved. Also, by setting the content of the inorganic filler (D) to be equal to or lower than the above upper limit value, easy disassembly and good fluidity of the resin composition can be obtained, and the moldability can be effectively improved.

[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. Thereby, aggregation of the thermally expandable inorganic material (C) and the inorganic filler (D) can be suppressed, and good fluidity can be obtained.

[0048] As the coupling agent, known coupling agents such as various silane-based compounds such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, vinyl silane, titanium-based compounds, aluminum chelates, aluminum / zirconium-based compounds, etc. can be used.

[0049] More specifically, silane coupling agents such as hydrolysis products of 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-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-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-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine;Examples of titanate coupling agents include isopropyltriisostearoyl titanate, isopropyltris(dioctyl pyrophosphate) titanate, isopropyltri(N-aminoethyl-aminoethyl) titanate, tetraoctylbis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl) phosphite titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, isopropylisostearoyl diacrylate titanate, isopropyltri(dioctyl phosphate) titanate, isopropyltricumylphenyl titanate, tetraisopropylbis(dioctyl phosphite) titanate, and the like. 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, more preferably 0.1% by mass or more and 2% by mass or less, based on the entire resin composition. By setting the content of the coupling agent to be equal to or higher than the above lower limit value, the dispersibility of the inorganic filler in the resin composition can be made good. Further, by setting the content of the coupling agent to be equal to or lower than the above upper limit value, the fluidity of the resin composition can be made good, and the moldability can be improved.

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

[0052] As the curing accelerator, specifically, for example, 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 like benzyldimethylamine, amidinium salts, or ammonium salts; phenolic compounds such as phenol, bisphenol A, nonylphenol, 2,3-dihydroxynaphthalene, etc. can be mentioned. Moreover, examples of the above-mentioned organic phosphines include triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium·tetraphenylborate, triphenylphosphine·triphenylborane, 1,2-bis-(diphenylphosphino)ethane, etc. These may be used alone or in combination of two or more.

[0053] The content of the curing accelerator is appropriately set according to the use, but it is preferably 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, based on the total amount of the resin composition. By setting the content of the curing accelerator to be not less than the above lower limit value, it becomes easier to appropriately cure the resin composition. On the other hand, by setting the content of the curing accelerator to be not more than the above upper limit value, the molten state can be prolonged and a lower viscosity state can be maintained for a longer time.

[0054] [Hydroxyl group-containing cyclic compound] When the resin composition of the present embodiment contains a curing accelerator, it may contain a compound in which hydroxyl groups are respectively bonded to two or more adjacent carbon atoms constituting an aromatic ring (hereinafter also referred to as "hydroxyl group-containing cyclic compound"). Thereby, even when a phosphorus atom-containing curing accelerator having no latency is used as the curing accelerator, the reaction during the melt-kneading of the resin composition can be suppressed, and the resin composition can be stably obtained. In addition, the hydroxyl group-containing cyclic compound also has the effect of lowering the melt viscosity of the resin composition and improving the fluidity.

[0055] As the hydroxyl group-containing cyclic compound, a monocyclic compound represented by the following general formula (5), a polycyclic compound represented by the following general formula (6), or the like can be used. These compounds may have substituents other than the hydroxyl group.

[0056]

Chemical formula

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

[0058]

Chemical formula

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

[0060] Specific examples of the monocyclic compound represented by general formula (5) include, for example, catechol, pyrogallol, gallic acid, gallic acid ester, or derivatives thereof. Specific examples of the polycyclic compound represented by the general formula (6) include, for example, 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, and their derivatives. Among these, compounds in which hydroxyl groups are bonded to two adjacent carbon atoms constituting the aromatic ring are preferred because of the ease of controlling fluidity and curability. Further, considering volatilization during the kneading process, it is more preferable that the parent nucleus is a naphthalene ring having 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 its derivatives. These hydroxyl group-containing cyclic compounds may be used alone or in combination of two or more.

[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 further preferably 0.05% by mass or more with respect to 100% by mass of the total value of the resin composition. When the content of the hydroxyl group-containing cyclic compound is within the above range, a sufficient reduction in viscosity and improvement in fluidity of the resin composition can be obtained. Also, 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 further preferably 0.5% by mass or less with respect to 100% by mass of the total value of the resin composition. When the content of the hydroxyl group-containing cyclic compound is within the above range, there is little risk of causing a decrease in curability of the resin composition or a decrease in physical properties of the cured product.

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

[0063] Examples of the above-mentioned flame retardant include inorganic flame retardants. Specific examples of the inorganic flame retardant include aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, phosphazene, and carbon black. As the flame retardant, one or more of the above specific examples can be blended. Among these, from the viewpoints of obtaining flame retardancy and easy decomposability, aluminum hydroxide is preferable.

[0064] In addition, aluminum hydroxide undergoes dehydration decomposition when exposed to high temperatures. Therefore, when a structure using the resin composition of this embodiment containing aluminum hydroxide is heated to 200 °C or higher, the structure can be destroyed from the inside by the dehydration decomposition of aluminum hydroxide, and the structure can be easily disassembled.

[0065] The lower limit of the content of aluminum hydroxide is preferably 1% by mass or more from the viewpoint of obtaining flame retardancy with respect to the total amount of the resin composition, preferably 40% by mass or more, and more preferably 50% by mass or more from the viewpoints of obtaining easy decomposability in addition to flame retardancy. On the other hand, the upper limit of the content of aluminum hydroxide can be appropriately set according to the use of the resin composition. For example, it may be 60% by mass or less.

[0066] In addition, from the viewpoint of obtaining easy decomposability by aluminum hydroxide while maintaining good moldability of the resin composition, the total content of the thermally expandable inorganic material (C), the inorganic filler (D), and aluminum hydroxide is preferably 60 to 95% by mass, more preferably 70 to 90% by mass, and even more preferably 75 to 85% by mass with respect to the total amount of the resin composition.

[0067] [Manufacturing method of resin composition] Next, the manufacturing method of the resin composition of this embodiment will be described. The method for manufacturing the resin composition of the present embodiment is not particularly limited. For example, each component other than the thermosetting component is mixed using a mixer or the like, and then melt-heated and kneaded at about 90 to 120 °C using a heating kneader, a hot roll, an extruder, or the like. Next, the obtained kneaded product is cooled and pulverized to obtain a powdery or granular resin composition. The resin composition may be tableted and formed into tablets after pulverization as needed, or may be formed into a sheet by, for example, vacuum lamination molding or compression molding after pulverization.

[0068] Also, for example, each component other than the thermosetting component may be dissolved, mixed, and stirred in a solvent using various mixers such as an ultrasonic dispersion method, a high-pressure collision dispersion method, a high-speed rotation dispersion method, a bead mill method, a high-speed shear dispersion method, or a rotation-revolution dispersion method to prepare a varnish-like resin composition. 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, carbitol-based, anisole, and N-methylpyrrolidone. The solvent may be used alone or in combination of two or more.

[0069] 2. Structure The structure of the present embodiment includes a cured product of the above easily decomposable resin composition. The cured product is obtained by thermosetting the resin composition of the present embodiment at 100 to 200 °C for 10 to 900 seconds.

[0070] Examples of the structure include composite members for transportation equipment such as automobiles, railways, ships, and aircraft, semiconductor chips, semiconductor elements, semiconductor devices including printed wiring boards, composite members for factory equipment such as industrial robots, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, chemical batteries, and other electronic devices, civil engineering and architectural composite members, sports and recreation composite members, etc., and can be widely applied. Among them, from the perspective of the importance of addressing environmental issues, etc., composite members for transportation equipment such as automobiles and semiconductor devices are preferred. Specifically, the semiconductor device includes a semiconductor element and a sealing material for sealing the semiconductor element, and an example is one in which the sealing material is made of a cured product of the resin composition of the present embodiment. The sealing method and the like are not particularly limited, and known methods can be used. Among them, specifically, it is preferably applied to rotors, stators, and power modules. Details thereof will be described later.

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

[0072] Hereinafter, an example of the rotor of the present embodiment will be described. FIG. 1 is a plan view showing a rotor 100 according to the present 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 the present 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. A hole 150 is provided in the rotor core 110. The magnet 120 is inserted into the hole 150. The fixing member 130 is provided at a separation portion 140 between the hole 150 and the magnet 120. The fixing member 130 is formed using the above-mentioned easily disassembled resin composition.

[0074] The rotor 100 according to this embodiment constitutes a motor mounted on, for example, an automobile or the like. The motor includes the rotor 100 and a stator provided 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. The rotation generated by the rotor 100 is transmitted to the outside via the rotating shaft 170.

[0075] The rotor core 110 is provided with 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 is, for example, circular or polygonal in plan view. As shown in FIG. 2, the rotor core 110 is formed by laminating a plurality of electromagnetic steel sheets 112 which are thin plate-shaped magnetic bodies. The electromagnetic steel sheet 112 is composed of, for example, iron or an iron alloy. Also, as shown in FIG. 2, end plates 118a and 118b are provided at both ends of the rotor core 110 in the axial direction. That is, the end plate 118a is provided on the laminated electromagnetic steel sheets 112. Also, the end plate 118b is provided under the laminated electromagnetic steel sheets 112. The end plates 118a and 118b are fixed to the rotating shaft 170 by, for example, welding.

[0076] FIG. 3 is an enlarged cross-sectional view showing the rotor 100 shown in FIG. 1. As shown in FIG. 3, caulking portions 160 are formed in the plurality of electromagnetic steel sheets 112. The caulking portion 160 is composed of, for example, a protrusion formed in the electromagnetic steel sheet 112. Each electromagnetic steel sheet 112 is coupled to each other by the caulking portion 160. Also, the end plate 118a is provided with a groove portion 116 for avoiding interference with, for example, the caulking portion 160 protruding from the electromagnetic steel sheet 112 and the fixing member 130 protruding on the electromagnetic steel sheet 112. The fixed member 130 protruding from the electromagnetic steel sheet 112 is a portion formed by the hardening of the easily decomposable resin composition remaining on the electromagnetic steel sheet 112 when the above-mentioned easily decomposable resin composition is injected into the separation portion 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 the present embodiment, for example, a plurality of hole groups each composed of two adjacent holes 150 are arranged along the peripheral edge of the rotating shaft 170. The plurality of hole groups are provided so as to be separated from each other, for example. The two holes 150 constituting one hole group are arranged in a V shape in a plan view, for example. In this case, the two holes 150 constituting one hole group are provided such that their respective end portions facing each other are located on the side of the rotating shaft 170, for example. Also, the two holes 150 constituting one hole group are provided so as to be separated from each other, for example.

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

[0079] FIG. 4 schematically shows a cross-sectional view in a direction perpendicular to the rotation axis direction of the motor 101. FIG. 5 schematically shows a cross-sectional view in the rotation axis direction of the motor 101. FIG. 6 is an enlarged view of the periphery of the slot (region X in FIG. 4), and schematically shows a 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, a rotor 2, a stator 4, and a coil 9 housed inside the case 1.

[0081] Case 1 is composed of a cylindrical portion 1a and side plate portions 1b and 1c that close both axial ends of the cylindrical portion 1a. As the material of the case 1, for example, an aluminum alloy (cast casting), a resin material, or a combination thereof can be used.

[0082] As shown in FIG. 4, the rotor 2 is housed inside the case 1. As shown in FIG. 5, a rotating shaft 3 is attached as a figure output shaft at the center of the rotor 2. Both ends of the rotating shaft 3 are supported by the side plate portions 1b and 1c via bearings 3a respectively. Thereby, the rotor 2 is rotatable about the rotating shaft 3.

[0083] The rotor 2 is internally provided with permanent magnets 5. Specifically, as shown in FIG. 4, a plurality (here, 8) of permanent magnets 5 are arranged at equal intervals on the same circumference. At this time, the magnetic poles of adjacent permanent magnets 5 are installed so as to be different from each other.

[0084] As shown in FIG. 5, a cylindrical stator 4 is arranged and fixed on the inner peripheral side 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 peripheral surface of the stator 4 and the outer peripheral surface of the rotor 2.

[0085] The stator core 41 is provided by laminating and tightly fixing a plurality of electromagnetic steel sheets in the axial direction. When viewed from the axial end as shown in FIG. 4, an annular yoke portion 6 and a plurality of teeth portions 7 extending from the yoke portion 6 toward the rotor 2 side (inner peripheral side) are provided. The plurality of teeth portions 7 are arranged at equal intervals in the circumferential direction. Here, as shown in FIG. 4, 24 teeth portions 7 are provided. Slots 8 are provided between each of the teeth portions 7. Further, a resin layer 50 that is wound around the teeth portion 7 with a resin composition and thinly covered is provided.

[0086] The coil 9 is in a flat rectangular U shape and is wound so as to be housed in two slots 8 spaced apart across the tooth portion 7. Here, the coil 9 is accommodated in a distributed winding manner in a liner member 20 disposed in the slot 8 (FIG. 4). The coil 9 has a first coil end and a second coil end. The first coil end projects to one axial side of the stator core 41. The second coil end projects to the other axial side of the stator core 41. That is, the coil 9 has a pair of coil ends that project to both axial sides of the stator core 41, respectively. The coil 9 is formed using a wire made of a conductor such as copper, aluminum, or iron in the shape of a wire.

[0087] The tooth portion 7 is provided corresponding to the permanent magnet 5 of the rotor 2 described above. By sequentially exciting each coil 9, the rotor 2 rotates due to attraction and repulsion with the corresponding permanent magnet 5.

[0088] The tooth portion 7 is formed with a large circumferential width on the outer peripheral side and a small width on the inner peripheral side, and is tapered toward the inner peripheral side. At the inner peripheral end of the tooth portion 7, tooth tips 71 facing each other along the circumferential direction are formed so as to reduce the width of the slot 8.

[0089] The slot 8 is a space between adjacent tooth portions 7, and as shown in FIG. 6, is provided such that the wall surfaces 72 of the tooth portions 7 facing each other along the radial direction are parallel planes. The space between the tooth tips 71 is the inner peripheral side opening of the slot 8. The slot 8 includes a plurality of coils 9 disposed on the outer peripheral side (yoke portion 6 side) and a resin sealing portion 65 provided on the inner peripheral side (tooth tip 71 side).

[0090] As shown in FIG. 6, the resin sealing portion 65 is provided on the inner peripheral side (tooth tip 71 side) of the slot 8. 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-described easily disassemblable 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 covers the coil 9 within the slot 8 and covers one of the pair of coil ends, in other words, covers only one of the first and second coil ends. In yet another embodiment, the resin sealing portion 65 covers the coil 9 within the slot 8 and covers both of the pair of coil ends, in other words, covers both of the first and second coil ends.

[0092] <Power module> FIG. 7 is a cross-sectional view showing the configuration of the power module (semiconductor device) 100 in the present 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 and is composed of, 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 composed of one or more semiconductors selected from the group consisting of SiC, GaN, Ga2O3, and diamond (c) A semiconductor element with a voltage of 1.0 V or more (d) A semiconductor element with a power density of 10 W / cm 3 or more

[0095] The power consumption of the semiconductor element 21 is, for example, 2.0 W or more, preferably 3.0 W or more, under the above-described condition (a), and may be, for example, 4.0 W or less. The voltage of the semiconductor element 21 is, for example, 1.0 V or more, preferably 3.0 V or more, under the above-described condition (c), and may be, for example, 5.0 V or more. Also, the voltage of the semiconductor element 21 may be, for example, 100 V or less. Also, the power density of the semiconductor element 21 is, for example, 10 W / cm 3 or more, preferably 20 W / cm 3 or more, and may be, for example, 30 W / cm 3 or more. Also, the power density of the semiconductor element 21 may be, for example, 200 W / cm 3 or less. Also, the semiconductor element 21 can operate, for example, in a high-temperature environment of 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 rectifying 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, for example, on the die pad 32 of the substrate 30 and is electrically connected to the outer lead 34 via the wire 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 the present embodiment is composed of a cured product of the above-described easily decomposable resin composition. The encapsulant 51 can be formed, for example, by encapsulating and molding the easily decomposable resin composition using a known method such as a transfer molding method or a compression molding method.

[0099] 3. Disassembly method The method for disassembling the structure of this embodiment includes a step of heating the structure to 200 °C or higher to disassemble the cured product of the easily disassembled resin composition. Since the cured product can be disassembled by heating, mechanical instruments for destroying the cured product are not required, and the occurrence of contamination, corrosion, etc. caused by using chemicals can be suppressed.

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

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

[0102] 4. Recycling method The recycling of this embodiment is a recycling method of the materials constituting the above structure, including a step of heating the structure to 200 °C or higher to disassemble the cured product of the easily disassembled resin composition, and a step of recovering the materials from the structure. Thereby, the materials used in the structure can be reused. The step of disassembling the cured product is the same as the method described in the above disassembly method.

[0103] Also, the method for recovering the materials from the structure is not particularly limited as long as the quality of the materials is not deteriorated. For example, a method of destroying the structure together with the cured product made brittle by disassembly and recovering the materials can be mentioned.

[0104] When the structure is a rotor, the materials recovered from the rotor are not particularly limited as long as they are heat-resistant. For example, metals (electromagnetic steel sheets), permanent magnets, etc. can be mentioned.

[0105] When the structure is a stator, the materials recovered from the stator are not particularly limited as long as they are heat-resistant. Examples include coils, metals (electromagnetic steel sheets), and the like.

[0106] When the structure is a power module, the materials recovered from the power module are not particularly limited as long as they are heat-resistant. Examples include metallic lead frames and the like.

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

Example

[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 Composition> Using the raw materials shown below, each component was mixed at the solid division ratio shown in Table 1 to obtain a mixture. The mixing was performed using a Henschel mixer at room temperature. Thereafter, the obtained mixture was roll-kneaded at 90 to 120 °C to obtain a kneaded product. After cooling the obtained kneaded product, it was pulverized to obtain each resin composition. [Raw Materials] (Thermosetting Resin (A)) ·Epoxy Resin 1: Biphenylene Skeleton-Containing Phenol Aralkyl-Type Epoxy Resin (Nippon Kayaku Co., Ltd., NC3000)

[0110] (Hardener (B)) ·Hardener 1: Biphenylene Skeleton-Containing Phenol Aralkyl-Type Resin (manufactured by Meiwa Kasei Co., Ltd., MEH-7851SS) ·Hardener 2: Biphenylene Skeleton-Containing Phenol Aralkyl-Type Resin (manufactured by Nippon Kayaku Co., Ltd., GPH-65)

[0111] (Thermally Expandable Inorganic Material (C)) · Heat-expandable inorganic material 1: Cristobalite-type silica (Cristobalite manufactured by Micron Co., Ltd.)

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

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

[0115] <Evaluation and measurement> (1) Adhesion strength Each obtained easily decomposable resin composition was molded onto a copper substrate (a copper plate of "EFTEC64-T" manufactured by Furukawa Electric Co., Ltd. with Cu strike plating) under the conditions of 175 °C, 6.9 MPa, and 120 seconds, and a test piece was obtained by further post-curing at 175 °C for 4 hours. The adhesion strength [N / mm 2 when measuring the shear adhesion with the copper substrate at room temperature at a speed of 300 μm / second using the test piece was designated as S1 [N / mm 2 . Furthermore, after heating the test piece at 300 °C for 30 minutes, the adhesion strength [N / mm 2 when measuring the shear adhesion with the copper substrate at room temperature at a speed of 300 μm / second was designated as S2 [N / mm 2 . The results are shown in Table 1.

[0116] (2) TMA measurement (glass transition temperature, coefficient of linear expansion) Each obtained easily decomposable resin composition was molded on a copper substrate under the conditions of 175 °C, 10 MPa, and 120 seconds, and a test piece subjected to post-curing at 175 °C for 4 hours was obtained. Using the test piece, measurement was performed with a thermomechanical analyzer (manufactured by Seiko Instruments Inc., TMA / SS6000) in the measurement temperature range of 25 °C to 320 °C at a heating rate of 5 °C / minute. From this measurement result, the glass transition temperature Tg (°C) was calculated. α1 was the coefficient of linear expansion at 40 °C to 80 °C, α2 was the coefficient of linear expansion at 190 °C to 230 °C, and α3 was the coefficient of linear expansion at 250 °C to 260 °C.

[0117] (3) Easy decomposability Each obtained easily decomposable resin composition was molded on a nickel plate under the conditions of 175 °C, 6.9 MPa, and 120 seconds, and a test piece subjected to post-curing at 175 °C for 4 hours was obtained. Furthermore, after heating the test piece at 300 °C for 30 minutes, it was cooled to room temperature, and the easy decomposability was evaluated according to the following criteria. (Criteria) 〇: The cured product of the test piece was peeled off from the nickel plate ×: The cured product of the test piece was not peeled off from the nickel plate

[0118]

Table 1

[0119] This application claims priority based on Japanese Patent Application No. 2023-040608 filed on March 15, 2023, and incorporates herein by reference the entire disclosure thereof.

Description of Reference Numerals

[0120] 1 Case 1a Cylindrical portion 1b Side plate portion 2 Rotor 3 Rotation shaft 3a Bearing 4 Stator 5 Permanent magnet 6 Yoke portion 7 Tooth 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-sealed portion 71 Tip of tooth portion 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 Spacing portion 150 Hole portion 160 Crimping portion 170 Rotating shaft

Claims

1. A resin composition that is easily disintegrated, comprising a thermosetting resin and one or more selected from a thermally expandable inorganic material, an inorganic filler (excluding the thermally expandable inorganic material), and aluminum hydroxide, wherein the thermosetting resin contains an epoxy resin, the total content of the thermally expandable inorganic material, the inorganic filler, and the aluminum hydroxide is 60% by mass or more based on the total amount of the easily disintegrated resin composition, the content of the inorganic filler is 1% by mass or more and 45% by mass or less based on the total amount of the easily disintegrated resin composition, the adhesion strength ratio (S2 / S1) measured by the following procedure is 0.30 or less, is in a powdery, granular, or tablet form, and an easily disintegrated resin composition that facilitates the disintegration of the cured product by heating the cured product of the easily disintegrated resin composition. [Procedure] A test piece is obtained by molding the easily disintegrated resin composition on a copper substrate under the conditions of 175°C, 6.9 MPa, and 120 seconds, and further performing post-curing at 175°C for 4 hours. Using the test piece, the adhesion strength [N / mm ２ when measuring the shear adhesion with the copper substrate at room temperature at a speed of 300 μm / sec is defined as S1 [N / mm ２ . Furthermore, after heating the test piece at 300°C for 30 minutes, the adhesion strength [N / mm ２ when measuring the shear adhesion with the copper substrate at room temperature at a speed of 300 μm / second was designated as S2 [N / mm ２ .

2. The easily disintegrated resin composition according to Claim 1, The adhesion strength (S2) measured by the above procedure is 3.0 N / mm ２ or less, a resin composition that is easily disassembled.

3. The easily disintegrated resin composition according to Claim 1 or 2, wherein the linear expansion coefficient α2 in the temperature range of 190°C to 230°C of the cured product obtained by molding the easily disintegrated resin composition under the conditions of 175°C, 6.9 MPa, and 120 seconds and further performing post-curing at 175°C for 4 hours is 46 ppm / °C or more.

4. The easily disintegrated resin composition according to Claim 1 or 2, wherein the linear expansion coefficient α3 in the temperature range of 250 to 260°C of the cured product obtained by molding the easily disintegrated resin composition under the conditions of 175°C, 6.9 MPa, and 120 seconds and further performing post-curing at 175°C for 4 hours is 60 ppm / °C or more.

5. The easily disintegrated resin composition according to Claim 1 or 2, further comprising a curing agent.

6. The easily disintegrated resin composition according to Claim 5, wherein the curing agent contains a phenolic curing agent.

7. The easily disintegrated resin composition according to Claim 1 or 2, wherein the content of the thermally expandable inorganic material is 5 to 98% by mass based on the total amount of the easily disintegrated resin composition.

8. The easily disintegrated resin composition according to Claim 1 or 2, A readily disintegrating resin composition, wherein the thermally expandable inorganic material contains one or more selected from crystalline silica, crystalline aluminum phosphate, and derivatives thereof.

9. The readily disintegrating resin composition according to claim 1 or 2, wherein the thermally expandable inorganic material contains one or more selected from quartz-type silica, cristobalite-type silica, tridymite-type silica, berlinite-type aluminum phosphate, tridarfite-type aluminum phosphate, crystalfite-type aluminum phosphate, and carnegieite, A readily disintegrating resin composition.

10. The readily disintegrating resin composition according to claim 1 or 2, wherein the content of the aluminum hydroxide is 1% by mass or more based on the total amount of the readily disintegrating resin composition, A readily disintegrating resin composition

11. A structure comprising a cured product of the readily disintegrating resin composition according to claim 1 or 2.

12. A method for disassembling the structure according to claim 11, including a step of heating the structure to 200°C or higher to disassemble the cured product of the readily disintegrating resin composition. A method for disassembling a structure.

13. A recycling method for the material constituting the structure according to claim 11, including a step of heating the structure to 200°C or higher to disassemble the cured product of the readily disintegrating resin composition; and a step of recovering the material from the structure. A recycling method.

14. The readily disintegrating resin composition according to claim 1 or 2, a rotor core fixed to a rotating shaft and provided with a plurality of holes arranged along the peripheral edge of the rotating shaft; a magnet inserted into the holes; A readily disintegrating resin composition used for forming the fixing member among the rotors including a fixing member provided in a separating portion between the holes and the magnet.

15. A rotor comprising a cured product of the readily disintegrating resin composition according to claim 14 as the fixing member.

16. A method for disassembling the rotor according to claim 15, including a step of heating the rotor to 200°C or higher to disassemble the cured product of the readily disintegrating resin composition. A method for disassembling a rotor.

17. A recycling method for the material constituting the rotor according to claim 15, including a step of heating the rotor to 200°C or higher to disassemble the cured product of the readily disintegrating resin composition; and a step of recovering the material from the rotor. A recycling method.

18. A recycling method according to claim 17, wherein the material is one or more selected from the group consisting of the magnet inserted into the hole portion and the electromagnetic steel sheet.

19. A readily disassemblable resin composition according to claim 1 or 2, wherein a stator core having a plurality of teeth portions and a plurality of slots formed alternately in the circumferential direction, a coil wound around the slot and having a pair of coil ends accommodated in the slot and protruding from both axial sides of the stator core, and a sealing member provided to cover the coil in the slot, and the readily disassemblable resin composition is used for forming the sealing member in the stator.

20. A stator comprising a cured product of the readily disassemblable resin composition according to claim 19 as the sealing member.

21. A method for disassembling a stator according to claim 20, wherein the method includes a step of heating the stator to 200 ° C or higher to disassemble the cured product of the readily disassemblable resin composition.

22. A recycling method for a material constituting the stator according to claim 20, wherein the method includes a step of heating the stator to 200 ° C or higher to disassemble the cured product of the readily disassemblable resin composition, and a step of recovering the material from the stator.

23. A recycling method according to claim 22, wherein the material is one or more selected from the group consisting of a coil and an electromagnetic steel sheet.

24. A readily disassemblable resin composition according to claim 1 or 2, wherein the readily disassemblable resin composition is used for forming the sealing member in a power module including a wiring board, a plurality of electronic components mounted on the wiring board, and a sealing member for sealing the electronic components.

25. A power module comprising a cured product of the readily disassemblable resin composition according to claim 24 as the sealing member.

26. A method for disassembling a power module according to claim 25, wherein the method includes a step of heating the power module to 200 ° C or higher to disassemble the cured product of the readily disassemblable resin composition.

27. A recycling method for a material constituting the power module according to claim 25, wherein the method includes a step of heating the power module to 200 ° C or higher to disassemble the cured product of the readily disassemblable resin composition, and A recycling method including a step of recovering the material from the power module.

28. The recycling method according to claim 27, wherein the material is a metal lead frame.

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