TW202348678A - Resin composition for molding, method of manufacturing encapsulated structure, and encapsulated structure - Google Patents

Abstract

This resin composition for molding is for collectively sealing: a substrate equipped with an electronic component; a stator core which is fixed onto the substrate and which has a plurality of slots formed in the circumferential direction; and a plurality of coils accommodated in the slots. The resin composition comprises: an epoxy resin; a curing agent and/or a curing catalyst; and an inorganic filler. A cured product yielded by curing the resin composition for molding at 140 DEG C for two minutes has a bending elastic modulus (according to JIS K6911:2006) at 25 DEG C of 0.1 GPa to 30 GPa.

Description

Resin composition for molding, manufacturing method of sealing structure, and sealing structure

The present invention relates to a molding resin composition, a manufacturing method of a sealing structure, and a sealing structure.

In order to protect electronic components such as semiconductor elements and structures such as stators from the external environment, sealing with thermosetting resin is widely used. In particular, the transfer molding method using epoxy resin as the sealing resin has excellent economical efficiency and productivity and is suitable for mass production, so it has become the mainstream of resin sealing.

As a technology of using a resin material in a stator core, there is one described in Patent Document 1 (Japanese Patent Application Publication No. 2003-284277). This patent document describes a rotating electrical machine that includes a stator in which a plurality of coils are wound at predetermined intervals around a stator core in which a plurality of electromagnetic steel plates are laminated; a rotor rotatably held in the stator; and a cooling frame. The stator is fixed. In this rotary electric machine, a highly thermally conductive composite material composed of a thermosetting resin with an anisotropic structure in the resin component is arranged in the groove of the winding portion that becomes the stator. This structure provides a The heat generated by the coil is easily transferred and the rotating motor has good heat dissipation properties. [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2003-284277

[Problem to be solved by the invention]

However, in the resin composition of the conventional technology, treatment at high temperatures is required for hardening, and there is room for improvement in workability. Furthermore, in sealing structures using conventional resin compositions, there is room for improvement in adhesion and waterproofness to structures such as electronic components and stators, and defects may occur in the sealing structure.

The present invention was made in view of this situation, and an object thereof is to provide a molding resin composition that can be cured at a low temperature and can improve the adhesiveness and waterproofness when sealing structures such as electronic parts and stators. [Technical means to solve the problem]

As a result of discussions, the present inventors completed the invention provided below and solved the above-mentioned problems.

The present invention provides the following resin composition for molding, a method of manufacturing a sealing structure, and a sealing structure.

[1] A molding resin composition used to combine a substrate mounted with electronic components, a stator core having a plurality of grooves formed along the circumferential direction and fixed to the substrate, and a plurality of coils housed in the grooves. Sealing, which contains: epoxy resin; one or both of a hardener and a hardening catalyst; and an inorganic filler material, and the cured product obtained by hardening the molding resin composition at 140°C for 2 minutes is at 25°C The bending elastic modulus (according to JIS K6911:2006) is 0.1GPa or more and 30GPa or less. [2] The molding resin composition of the above [1], wherein the glass transition temperature (Tg) measured by the following (Method 1) is 140°C or more and 300°C or less. (Method 1) Using a transfer molding machine, mold the above-mentioned molding resin composition into a test piece of 80 mm × 10 mm × 4 mm under the conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 90 seconds, and Post hardening at 175°C for 2 hours. Furthermore, a thermal mechanical analysis device was used to measure the thermal expansion coefficient of the test piece obtained at a temperature rising rate of 5° C./min. Next, based on the obtained measurement results, the glass transition temperature (Tg) (℃) of the hardened material is calculated from the inflection point of the thermal expansion coefficient. [3] The molding resin composition according to the above [1] or [2], wherein the epoxy resin contains a phenol novolac type epoxy resin, a cresol novolac type epoxy resin and a trisphenolmethane type epoxy resin. One or more of the group consisting of oxygen resins. [4] The molding resin composition according to any one of [1] to [3] above, wherein the content of the epoxy resin is: 3 mass% or more and 40 mass% or less. [5] The molding resin composition according to any one of the above [1] to [4], which contains the above-mentioned curing agent, and the above-mentioned curing agent contains a phenolic resin-based curing agent. [6] The molding resin composition of the above [5], wherein the phenolic resin hardener contains a phenol novolac resin, a cresol novolak resin, a naphthol novolak resin, and a trisphenolmethane type phenol resin. 1 or 2 or more species in the group. [7] The molding resin composition according to the above [5] or [6], wherein the content of the hardener is 0.8 mass% or more when the total solid content of the molding resin composition is 100 mass% and 12% by mass or less. [8] The molding resin composition according to any one of the above [1] to [7], which contains the above-mentioned curing catalyst, and the above-mentioned curing catalyst contains an imidazole compound. [9] The molding resin composition according to the above [8], wherein the content of the curing catalyst is 0.01 mass % or more and 2.0 mass % when the total solid content of the molding resin composition is 100 mass %. the following. [10] The molding resin composition according to any one of the above [1] to [9], wherein the molding is measured under the conditions of a mold temperature of 175°C, an injection pressure of 9.8MPa, and a curing time of 3 minutes. The spiral flow obtained from the resin composition is set to S ₁ . After the molding resin composition is left at 25°C for 48 hours, the measurement is performed under the conditions of a mold temperature of 175°C, an injection pressure of 9.8MPa, and a curing time of 3 minutes. When the obtained spiral flow is set to S ₂ , S ₂ ≥0.8×S ₁ is satisfied. [11] The molding resin composition according to any one of the above [1] to [10], wherein the time for the torque value measured by the following (Method 2) to reach 2N·m does not reach 100 seconds. (Method 2) Using a CURELASTOMETER (registered trademark), measure the torque value of the molding resin composition over time under the conditions of a mold temperature of 140°C and an amplitude angle of ±0.25 degrees. Based on the measurement results, calculate the time (seconds) for the torque value to reach 2N·m from the beginning of measurement. [12] The molding resin composition according to any one of the above [1] to [11], wherein the spiral flow measured by the following (Method 3) is 70 cm or more. (Method 3) Use a low-pressure transfer molding machine to inject the above-mentioned molding material into a spiral flow measurement mold in accordance with ANSI/ASTM D 3123-72 at 175°C, an injection pressure of 6.9MPa, and a holding time of 3 minutes. For the resin composition, measure the flow length and set it as spiral flow (cm). [13] The molding resin composition according to any one of [1] to [12] above, wherein the gelling time measured by the following (Method 4) is 30 seconds or more. (Method 4) Use a low-pressure transfer molding machine to inject the above molding material into the spiral flow measurement mold in accordance with ANSI/ASTM D 3123-72 at 175°C, an injection pressure of 6.9MPa, and a holding time of 3 minutes. Resin composition. The time from the start of injection to the time when the molding resin composition hardens and stops flowing is measured as the gelling time (seconds). [14] The molding resin composition according to any one of the above [1] to [13], wherein the linear expansion coefficient α1 measured by the following (Method 5) is 10.0 ppm/°C or less. (Method 5) Use a low-pressure transfer molding machine to inject the above-mentioned molding resin composition under the conditions of a mold temperature of 175°C, an injection pressure of 9.8MPa, and a curing time of 3 minutes to obtain a 15mm×4mm×4mm Molded products. Next, the obtained molded article was post-hardened at 175° C. for 4 hours to prepare a test piece. Thereafter, for the obtained test piece, a thermomechanical analysis device was used to measure the average linear expansion coefficient α1 at 25-70°C under the conditions of a measurement temperature range of 0°C to 400°C and a temperature rise rate of 5°C/min. (ppm/℃). [15] The molding resin composition according to any one of the above [1] to [14], wherein the thermal conductivity measured by the following (Method 6) is 0.5 W/m·K or more. (Method 6) Using a transfer molding machine, under the conditions of a mold temperature of 175°C, an injection pressure of 6.9MPa, and a curing time of 90 seconds, the above-mentioned molding resin composition is injected and molded to obtain an 80 mm × 10 mm × 4 mm Formed body. Next, the obtained molded body was post-hardened at 175° C. for 2 hours to obtain a test piece. The thermal diffusivity of the obtained test piece was measured using the laser flash method. Furthermore, an electronic hydrometer was used to measure the specific gravity of the test piece used for thermal conductivity measurement. Furthermore, a differential scanning calorimeter was used to measure the specific heat of the test piece for thermal conductivity and specific gravity measurement. Based on the measured values of thermal diffusivity, specific gravity, and specific heat, calculate the thermal conductivity (W/m·K) of the test piece in the thickness direction. [16] A method of manufacturing a sealed structure, which includes the following steps: arranging a substrate loaded with electronic components in a mold in a transfer molding machine, and a stator having a plurality of grooves formed along the circumferential direction and fixed to the substrate The iron core and the plurality of coils accommodated in the above-mentioned slots; and by the transfer molding method using the above-mentioned transfer molding machine, the above-mentioned molding resin composition in any one of the above-mentioned [1] to [15] is used in the above-mentioned mold. The substrate, the stator core, and the coil are sealed and molded to obtain a sealed structure. [17] The method of manufacturing a sealed structure according to the above [16], wherein in the step of obtaining the sealed structure, the sealing molding is performed at a temperature equal to or lower than Tg of the cured body of the molding resin composition. [18] The method for manufacturing a sealing structure according to the above [16] or [17], wherein the post-hardening step is not performed as the step of obtaining the sealing structure. [19] A sealing structure including a sealed body and a sealing member. The sealed body includes a substrate on which electronic components are mounted, and a stator fixed on one surface of the substrate and having a plurality of grooves formed along the circumferential direction. An iron core and a plurality of coils accommodated in the above-mentioned slot; The above-mentioned sealing member is provided to cover a part or all of the above-mentioned sealed body, and the above-mentioned sealing member is made of the molding resin composition according to any one of the above [1] to [15]. Made of hardened material. [Effects of the invention]

The present invention provides a molding resin composition that can be cured at a low temperature and can improve the adhesiveness and waterproofness when sealing structures such as electronic parts and stators.

Hereinafter, embodiments of the present invention will be described using drawings. In addition, in all drawings, the same components are denoted by the same symbols, and descriptions thereof are appropriately omitted. In this specification, unless otherwise specified, the symbols "X to Y" related to the numerical range indicate X or more and Y or less. In this specification, unless otherwise specified, the description of the upper limit and the lower limit regarding the numerical range can be arbitrarily combined with the described upper limit and lower limit.

<Resin composition for molding> The molding resin composition of this embodiment is used to seal together a substrate mounted with electronic components, a stator core having a plurality of grooves formed along the circumferential direction and fixed on the substrate, and a plurality of coils housed in the grooves. It contains: epoxy resin; curing catalyst; and inorganic filler material, and the bending elastic modulus at 25°C of the cured product obtained by hardening the molding resin composition at 140°C for 2 minutes (according to JIS K6911: 2006) It is 0.1GPa or more and 30GPa or less.

The molding resin composition of this embodiment is used to seal together a substrate mounted with electronic components, a stator core having a plurality of grooves formed in the circumferential direction and fixed to the substrate, and a plurality of coils housed in the grooves. The method of using the moldable resin composition according to this embodiment as a sealing material will be described in detail below.

Regarding the molding resin composition of this embodiment, the cured product obtained by curing the molding resin composition at 140° C. for 2 minutes has a bending elastic modulus at 25° C. (in accordance with JIS K6911:2006) of 0.1 GPa or more and Below 30GPa. The molding resin composition of this embodiment has a flexural elastic modulus within the above numerical range and can be cured at low temperature, thereby improving the adhesiveness and waterproofness when sealing structures such as electronic components and stators.

Although the mechanism for exerting such an effect is unclear, it is thought that by having the flexural elastic modulus within the above numerical range, when a certain load is applied to the cured product of the molding resin composition of the present embodiment, the bending elasticity in the cured product can be suppressed. Fine cracks occur, and as a result, the adhesiveness and waterproofness when sealing structures such as electronic parts and stators can be improved.

Regarding the molding resin composition of this embodiment, the lower limit value of the bending elastic modulus at 25°C (according to JIS K6911:2006) of the cured product obtained by curing the molding resin composition at 140°C for 2 minutes is: 0.1GPa or more, but preferably 1.0GPa or more, more preferably 3.0GPa or more, still more preferably 5.0GPa or more, still more preferably 8.0GPa or more, still more preferably 10.0GPa or more, still more preferably 12.0GPa or more , and more preferably 13.0GPa or more. By setting the flexural elastic modulus to be equal to or higher than the above-mentioned lower limit, a structure having excellent mechanical strength can be obtained even during low-temperature hardening. Moreover, the upper limit of the bending elastic modulus is 30 GPa or less, but it is preferably 27.0 GPa or less, more preferably 24.0 GPa or less, and still more preferably 21.0 GPa or less. By setting the bending elastic modulus below the above-mentioned upper limit, the stress accumulated in the hardened material becomes sufficiently small, thereby reducing warpage. This can improve the tightness and waterproofness when sealing structures such as electronic components and stators, making it less likely to cause defects in the structure.

Here, the bending elastic modulus at 25° C. of the molding resin composition of the present embodiment can be measured, for example, by the following method. Using a low-pressure transfer molding machine, the resin composition was injected and molded under the conditions of a mold temperature of 140°C, an injection pressure of 9.8MPa, and a hardening time of 2 minutes, and a length of 80mm, a width of 10mm, and a thickness of 4mm were obtained. Formed objects. The obtained molded article was post-hardened by heat treatment at 200° C. for 4 hours and was used as a test piece. The flexural elastic modulus could be measured at an ambient temperature of 25° C. in accordance with JIS K6911:2006. As a low-pressure transfer molding machine, for example, KTS-15 and KTS-30 (manufactured by KOHTAKI Corporation) can be used.

Each component used in the molding resin composition of this embodiment will be described below.

[Epoxy resin] Examples of the epoxy resin used in the molding resin composition of the present embodiment include novolak-type epoxy resins such as phenol novolak-type epoxy resins and cresol novolak-type epoxy resins, and bisphenol A. Type epoxy resin, bisphenol F type epoxy resin and other bisphenol type epoxy resins, N,N-diepoxypropylaniline, N,N-diepoxypropyltoluidine, diaminodiphenylmethane Aromatic glycidylamine-type epoxy resins such as aminobenzene-type glycidylamine, hydroquinone-type epoxy resin, biphenyl-type epoxy resin, stilbene-type epoxy resin, etc. Oxygen resin, trisphenolmethane type epoxy resin, trisphenolpropane type epoxy resin, alkyl modified trisphenolmethane type epoxy resin, epoxy resin containing trisphenol core, dicyclopentadiene modified phenol type epoxy resin Oxygen resin, naphthol type epoxy resin, naphthalene type epoxy resin, phenol aralkyl type epoxy resin with phenylene group and/or diphenylene group skeleton, phenol aralkyl type epoxy resin with phenylene group and/or diphenylene group skeleton Naphthol aralkyl type epoxy resin and other aralkyl type epoxy resin and other aromatic epoxy resin, vinylcyclohexene dioxide (vinylcyclohexene dioxide), dicyclopentadiene oxide (dicyclopentadiene oxide), Aliphatic epoxy resins such as alicyclic diepoxy-adipate and other alicyclic epoxy resins. These may be used individually or in mixture of 2 or more types. Among them, the epoxy resin used in the molding resin composition of the present embodiment preferably contains a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, and a trisphenolmethane type epoxy resin. One or more of the group consisting of resins.

In order to further improve the adhesiveness and waterproofness when sealing structures such as electronic parts and stators, when the total solid content of the molding resin composition is 100% by mass, the molding resin composition of this embodiment The lower limit of the content of the epoxy resin in is preferably 3 mass% or more, more preferably 4 mass% or more, further preferably 5 mass% or more, further preferably 6 mass% or more, still more preferably 7 Quality% or more. In addition, in order to obtain a structure with excellent mechanical strength even during low-temperature curing, when the total solid content of the molding resin composition is 100% by mass, the upper limit of the epoxy resin content is preferably 40%. % by mass or less, more preferably 30 % by mass or less, still more preferably 20 % by mass or less, still more preferably 15 % by mass or less. In order to further improve the adhesion and waterproofness when sealing structures such as electronic parts and stators, and to obtain a structure with excellent mechanical strength even when curing at low temperature, the solid content of the molding resin composition is When it is 100 mass %, the content of the epoxy resin in the molding resin composition of this embodiment is preferably 3 mass % or more and 40 mass % or less, more preferably 4 mass % or more and 30 mass % or less, and further The content is preferably 5 mass% or more and 20 mass% or less, further preferably 6 mass% or more and 20 mass% or less, and still more preferably 7 mass% or more and 15 mass% or less.

(hardener) The molding resin composition of this embodiment contains one or both of a curing agent and a curing catalyst. In order to three-dimensionally crosslink the epoxy resin, the molding resin composition of the present embodiment preferably contains a curing agent. When containing a curing agent as an essential component, it is more preferable to contain a phenolic resin-based curing agent. Examples of the phenol resin-based hardener include novolak-type phenol resins such as phenol novolak resin, cresol novolac resin, and naphthol novolac resin; polyfunctional phenol resins such as trisphenolmethane-type phenol resin; and terpenes. Modified phenol resin, dicyclopentadiene modified phenol resin and other modified phenol resins; phenol aralkyl resin with phenylene skeleton and/or biphenylene skeleton, phenol aralkyl resin with phenylene and/or biphenylene skeleton Aralkyl-type phenol resins such as naphthol aralkyl resins with a base skeleton; bisphenol compounds such as bisphenol A and bisphenol F, etc. can be used alone or in combination of two or more.

The molding resin composition of this embodiment preferably contains one or two or more types selected from the group consisting of phenol novolak resin, cresol novolac resin, naphthol novolak resin, and trisphenolmethane type phenol resin. Such a phenolic resin-based curing agent achieves a good balance of flame resistance, moisture resistance, electrical properties, curability, storage stability, and the like. In particular, in terms of curability, for example, the hydroxyl equivalent weight of the phenol resin-based curing agent can be 90 g/eq or more and 250 g/eq or less.

Furthermore, examples of the curing agent that can be used in combination include an additive type curing agent, a catalyst type curing agent, a condensation type curing agent, and the like.

As compound-additive hardeners, for example, in addition to aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), m-xylenediamine (MXDA), and diaminodiphenylmethane (DDM) In addition to aromatic polyamines such as m-phenylenediamine (MPDA) and diaminodiphenylsulfone (DDS), there are also polyamine compounds containing dicyandiamine (DICY) and organic acid dihydrazide; Hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA) and other alicyclic acid anhydrides, 1,2,4-benzenetricarboxylic anhydride (TMA), 1,2,4,5- Anhydrides containing aromatic anhydrides such as pyromellitic anhydride (PMDA) and benzophenone tetracarboxylic dianhydride (BTDA); polyphenol compounds such as novolac-type phenol resins and phenol polymers; polysulfides, Polythiol compounds such as thioesters and thioethers; isocyanate compounds such as isocyanate prepolymers and blocked isocyanates; organic acids such as polyester resins containing carboxylic acid, etc.

Examples of the catalyst type hardening agent include tertiary amine compounds such as dimethylbenzylamine (BDMA) and 2,4,6-tridimethylaminomethylphenol (DMP-30); 2-methylimidazole , 2-ethyl-4-methylimidazole (EMI24) and other imidazole compounds; BF ₃ complex and other Lewis acids, etc.

Examples of the condensation-type curing agent include sol phenolic resin, urea resin such as methylol-containing urea resin, melamine resin such as methylol-containing melamine resin, and the like.

When such other hardeners are used together, the lower limit of the content of the phenolic resin-based hardener is preferably 20 mass % or more, more preferably 30 mass % or more, and still more preferably 50 mass % with respect to all hardeners. % or more, more preferably 70 mass % or more, further preferably 90 mass % or more. When the content of the phenol resin-based hardener is equal to or greater than the above-mentioned lower limit, good fluidity can be exhibited while maintaining curability at low temperatures. In addition, the upper limit of the content of the phenolic resin-based hardener is not particularly limited, but it is preferably 100 mass % or less based on all the hardeners.

The lower limit of the total value of the curing agent content in the molding resin composition of the present embodiment is not particularly limited. However, when the total solid content of the molding resin composition is 100% by mass, it is preferably 0.8 mass%. % or more, more preferably 1 mass % or more, still more preferably 1.5 mass % or more, still more preferably 2 mass % or more, still more preferably 3 mass % or more, still more preferably 4 mass % or more. When the total value of the curing agent content is equal to or greater than the above-mentioned lower limit, good curing properties can be obtained. Moreover, the upper limit of the total value of the curing agent content in the molding resin composition is not particularly limited, but it is preferably 12 mass % or less, and more preferably 10 mass % based on the entire molding resin composition. or less, and more preferably 8 mass% or less.

In addition, the phenolic resin and epoxy resin used as the hardener are preferably based on the equivalent ratio (EP)/(OH) of the number of epoxy groups (EP) in the molding resin composition to the number of phenolic hydroxyl groups (OH) of all the phenolic resins. It is blended so that it becomes 0.8 or more and 1.6 or less. When the equivalent ratio is within the above range, sufficient curing characteristics can be obtained when the obtained molding resin composition is molded. However, when a resin other than a phenol resin capable of reacting with the epoxy resin is used in combination, the equivalent ratio may be appropriately adjusted.

[hardening catalyst] When the molding resin composition of this embodiment contains a curing catalyst as an essential component, an imidazole compound is preferably used as the curing catalyst used in the molding resin composition of this embodiment. The imidazole compound may contain, for example, a compound selected from the group consisting of imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, and 2-ethyl-4-methyl. Imidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2- Methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2 -Imidazole compounds such as phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl 1,2,4-benzenetricarboxylic acid- 2-Undecylimidazolium, 1-cyanoethyl-2-phenylimidazolium 1,2,4-benzenetricarboxylate, 2,4-diamino-6-[2'-methylimidazolium ( 1')]-Ethyl-Symtritris, 2,4-diamino-6-[2'-Undecalylimidazolyl (1')]-ethyl-Symtris, 2,4-Diamine 1 ')]-ethyl-isocyanuric acid adduct of symmetric tri-tris, the isocyanuric acid adduct of 2-phenylimidazole, and the isocyanuric acid adduct of 2-methylimidazole One or more than two kinds.

When an imidazole compound is used as a curing catalyst, when the total solid content of the molding resin composition is 100 mass %, the content of the imidazole compound is preferably 0.01 mass % or more, more preferably 0.03 mass % or more. , more preferably 0.05 mass% or more, further preferably 0.1 mass% or more, still more preferably 0.3 mass% or more, still more preferably 0.5 mass% or more, still more preferably 1.0 mass% or more. By setting the content of the imidazole compound to be equal to or higher than the above lower limit, it is possible to improve the adhesiveness and waterproofness when sealing structures such as electronic components and stators. In addition, the hardenability at low temperatures during sealing molding can also be improved. On the other hand, when the total solid content of the molding resin composition is 100% by mass, the content of the imidazole compound is preferably 2.0% by mass or less, more preferably 1.5% by mass or less. By setting the content of the imidazole compound to be equal to or less than the above upper limit, the fluidity during transfer to the injection mold can be improved, which can contribute to improvement of filling properties.

In addition to the imidazole compound, the hardening catalyst can also contain, for example, an organic phosphine, a tetra-substituted phosphonium compound, a phosphobetaine compound, an adduct of a phosphine compound and a quinone compound, and an adduct of a phosphonium compound and a silane compound. Compounds containing phosphorus atoms; one or more of two or more amine curing catalysts other than imidazole compounds such as 1,8-diazabicyclo(5,4,0)undecene.

Examples of organic phosphine include primary phosphine such as ethylphosphine and phenylphosphine; secondary phosphine such as dimethylphosphine and diphenylphosphine; trimethylphosphine, triethylphosphine, tributylphosphine, triphenylphosphine, etc. Tertiary phosphine such as base phosphine.

Examples of the tetrasubstituted phosphonium compound include compounds represented by the following general formula (4).

In the above general formula (4), P represents a phosphorus atom. R ⁴ , R ⁵ , R ⁶ and R ⁷ represent an aromatic group or an alkyl group. A represents the anion of an aromatic organic acid having at least one functional group selected from a hydroxyl group, a carboxyl group, and a thiol group in an aromatic ring. AH represents an aromatic organic acid having at least one functional group selected from a hydroxyl group, a carboxyl group, and a thiol group in an aromatic ring. x and y are numbers from 1 to 3, z is a number from 0 to 3, and x=y.

The compound represented by general formula (4) can be obtained, for example, as follows, but is not limited thereto. First, the tetra-substituted phosphonium halide, aromatic organic acid and base are added to the organic solvent and mixed uniformly to generate aromatic organic acid anions inside the solution system. Next, when water is added, the compound represented by general formula (4) can be precipitated. In the compound represented by the general formula (4), it is preferable that R ⁴ , R ⁵ , R ⁶ and R ⁷ bonded to the phosphorus atom are phenyl groups, and AH is a compound having a hydroxyl group in the aromatic ring, that is, a phenol. And A is the anion of the phenol. Examples of the phenols include monocyclic phenols such as phenol, cresol, resorcinol, and catechol; condensed polycyclic phenols such as naphthol, dihydroxynaphthalene, and anthracendiol; bisphenol A; Bisphenols such as phenol F and bisphenol S, polycyclic phenols such as phenylphenol and biphenol, etc.

Examples of the phosphate betaine compound used as a curing catalyst include compounds represented by the following general formula (5).

In the above general formula (5), P represents a phosphorus atom. R ⁸ represents an alkyl group having 1 to 3 carbon atoms, and R ⁹ represents a hydroxyl group. f is a number from 0 to 5, and g is a number from 0 to 3.

The compound represented by general formula (5) is obtained, for example, in the following manner. First, it is obtained through a step of bringing a triaromatic substituted phosphine, which is a tertiary phosphine, into contact with a diazonium salt, and substituting the diazo group of the triaromatic substituted phosphine and the diazonium salt. However, it is not limited to this.

Examples of the adduct of a phosphine compound and a quinone compound used as a curing catalyst include compounds represented by the following general formula (6).

In the above general formula (6), P represents a phosphorus atom. R ¹⁰ , R ¹¹ and R ¹² represent an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, and may or may not be the same as each other. R ¹³ , R ¹⁴ and R ¹⁵ represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and may be the same or different from each other. R ¹⁴ and R ¹⁵ may be bonded to form a cyclic structure.

As the phosphine compound used as an adduct of a phosphine compound and a quinone compound, for example, triphenylphosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, trinaphthylphosphine, tris( The aromatic ring such as benzyl) phosphine is unsubstituted or has a substituent such as an alkyl group or an alkoxy group. Examples of the substituent such as an alkyl group or an alkoxy group include those having a carbon number of 1 to 6. In terms of easy availability, triphenylphosphine is preferred.

Examples of the quinone compound used as an adduct of a phosphine compound and a quinone compound include benzoquinone and anthraquinones. Among them, p-benzoquinone is preferred in terms of storage stability.

As a method for producing an adduct of a phosphine compound and a quinone compound, the adduct can be obtained by contacting and mixing the organic tertiary phosphine and the benzoquinones in a solvent capable of dissolving both. As the solvent, among ketones such as acetone and methyl ethyl ketone, those with low solubility in the adduct are preferred. However, it is not limited to this.

In the compound represented by the general formula (6), R ¹⁰ , R ¹¹ and R ¹² bonded to the phosphorus atom are phenyl groups, and R ¹³ , R ¹⁴ and R ¹⁵ are hydrogen atoms, that is, 1,4 - A compound obtained by adding benzoquinone to triphenylphosphine is preferable in terms of reducing the thermal elastic modulus of the cured product of the molding resin composition.

Examples of the adduct of a phosphonium compound and a silane compound used as a curing catalyst include compounds represented by the following general formula (7).

In the above general formula (7), P represents a phosphorus atom, and Si represents a silicon atom. R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ respectively represent an organic group or an aliphatic group having an aromatic ring or a heterocyclic ring, and may be the same as each other or different from each other. In the formula, R ²⁰ is an organic group bonded to Y ² and Y ³ . In the formula, R ²¹ is an organic group bonded to Y ⁴ and Y ⁵ . Y ² and Y ³ represent groups in which proton-donating groups release protons, and groups Y ² and Y ³ in the same molecule are bonded to silicon atoms to form a chelate structure. Y ⁴ and Y ⁵ represent groups in which proton-donating groups release protons, and groups Y ⁴ and Y ⁵ in the same molecule are bonded to silicon atoms to form a chelate structure. R ²⁰ and R ²¹ may be the same as each other or different from each other, and Y ² , Y ³ , Y ⁴ and Y ⁵ may be the same as or different from each other. Z ¹ is an organic group or aliphatic group having an aromatic ring or heterocyclic ring.

In the general formula (7), examples of R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ include phenyl, methylphenyl, methoxyphenyl, hydroxyphenyl, naphthyl and hydroxynaphthyl. , benzyl, methyl, ethyl, n-butyl, n-octyl and cyclohexyl, etc., among them, phenyl, methylphenyl, methoxyphenyl, hydroxyphenyl, hydroxynaphthyl are more preferred Such as alkyl groups, alkoxy groups, hydroxyl groups and other substituted aromatic groups or unsubstituted aromatic groups.

Moreover, in the general formula (7), R ²⁰ is an organic group bonded to Y ² and Y ³ . Likewise, R ²¹ is an organic group bonded to groups Y ⁴ and Y ⁵ . Y ² and Y ³ are groups formed by releasing protons from a proton-donating group, and the groups Y ² and Y ³ in the same molecule are bonded to silicon atoms to form a chelate structure. Similarly, Y ⁴ and Y ⁵ are groups in which proton-donating groups release protons, and groups Y ⁴ and Y ⁵ in the same molecule are bonded to silicon atoms to form a chelate structure. The groups R ²⁰ and R ²¹ may be the same as or different from each other, and the groups Y ² , Y ³ , Y ⁴ and Y ⁵ may be the same as or different from each other. The groups represented by Y ² -R ²⁰ -Y ³ - and -Y ⁴ -R ²¹ -Y ⁵ - in the general formula (7) are composed of a proton donor releasing two protons, as The proton donor is preferably an organic acid having at least two carboxyl groups or hydroxyl groups in the molecule, further preferably an aromatic compound having at least two carboxyl groups or hydroxyl groups at adjacent carbons constituting the aromatic ring, and even more preferably Aromatic compounds in which adjacent carbons constituting an aromatic ring have at least two hydroxyl groups, for example, catechol, galenol, 1,2-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,2' -Biphenol, 1,1'-bi-2-naphthol, salicylic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, cloranic acid, tannic acid, 2-hydroxybenzyl alcohol, 1,2-cyclohexanediol, 1,2-propanediol, glycerin, etc., but among these, catechol, 1,2-dihydroxynaphthalene, and 2,3-dihydroxynaphthalene are more preferred.

Moreover, Z ¹ in the general formula (7) represents an organic group or an aliphatic group having an aromatic ring or a heterocyclic ring. Specific examples thereof include methyl, ethyl, propyl, butyl, hexyl and Aliphatic hydrocarbon groups such as octyl, phenyl, benzyl, naphthyl and biphenyl and other aromatic hydrocarbon groups, glycidoxypropyl, mercaptopropyl, aminopropyl, etc. have glycidoxy, mercapto, amine Reactive substituents such as alkyl groups and vinyl groups, etc., among these, methyl, ethyl, phenyl, naphthyl and biphenyl groups are more preferred from the viewpoint of thermal stability.

As a method of producing an adduct of a phosphonium compound and a silane compound, a silane compound such as phenyltrimethoxysilane and a proton donor such as 2,3-dihydroxynaphthalene are added and dissolved in a flask containing methanol, and then, The sodium methoxide-methanol solution was added dropwise with stirring at room temperature. Furthermore, when a prepared solution of a tetra-substituted phosphonium halide such as tetraphenylphosphonium bromide dissolved in methanol is added dropwise thereto with stirring at room temperature, crystals are precipitated. If the precipitated crystals are filtered, washed with water and dried in a vacuum, an adduct of a phosphonium compound and a silane compound can be obtained. However, it is not limited to this.

When the total solid content of the molding resin composition is 100 mass %, the content of the curing catalyst in the molding resin composition of this embodiment is preferably 0.1 mass % or more, more preferably 0.3 mass % or more, and further The content is preferably 0.5 mass% or more, and further preferably 1.0 mass% or more. By setting the content of the curing catalyst to be equal to or greater than the above-mentioned lower limit, the curability of the molding resin composition during transfer to the injection mold can be effectively improved, and the curability at low temperatures can be improved. On the other hand, when the total solid content of the molding resin composition is 100% by mass, the content of the curing catalyst is preferably 2.0% by mass or less, more preferably 1.7% by mass or less, still more preferably 1.5% by mass or less. . By setting the content of the curing catalyst to the above upper limit or less, fluidity during sealing can be improved, which can contribute to improvement of filling properties.

[Inorganic filler material] Examples of the inorganic filler used in the molding resin composition of this embodiment include fused silica such as fused crushed silica and fused spherical silica, crystalline silica, alumina, and kaolin. , Talc, clay, mica, rock wool, silica limestone, glass powder, glass flakes, glass beads, glass fiber, silicon carbide, silicon nitride, aluminum nitride, carbon black, graphite, titanium dioxide, calcium carbonate, calcium sulfate, Barium carbonate, magnesium carbonate, magnesium sulfate, barium sulfate, cellulose, aramid, wood, pulverized powder obtained by pulverizing the hardened material of phenolic resin molding materials or epoxy resin molding materials, etc. Among them, silica such as fused crushed silica, fused spherical silica, and crystalline silica is preferred, and fused spherical silica is more preferred. Among them, calcium carbonate and wollastonite are preferred in terms of cost. One type of inorganic filler material may be used, or two or more types may be used in combination.

The average particle diameter D ₅₀ of the inorganic filler is preferably from 0.01 μm to 75 μm, more preferably from 0.05 μm to 50 μm. By setting the average particle diameter D ₅₀ of the inorganic filler within the above range, the filling property in the mold during molding is improved. Furthermore, by setting the upper limit of the average particle diameter D ₅₀ of the inorganic filler to 75 μm or less, the filling property is further improved. The average particle diameter D ₅₀ is the volume-converted average particle diameter measured using a laser diffraction measuring device RODOS SR type (SYMPATEC HEROS & RODOS).

Moreover, the molding resin composition of this embodiment can contain two or more types of spherical silicas having different average particle diameters D ₅₀ as inorganic fillers. This can improve the fluidity and filling properties when transferring to the injection mold.

When the total solid content of the molding resin composition is 100 mass %, the content of the inorganic filler in the molding resin composition of this embodiment is preferably 50 mass % or more, more preferably 60 mass % or more, and further Preferably it is 65 mass % or more, More preferably, it is 70 mass % or more, Still more preferably, it is 75 mass % or more. If the content of the inorganic filler is equal to or more than the above-mentioned lower limit, it is possible to reduce the increase in moisture absorption and the decrease in strength associated with hardening of the obtained molding resin composition. Furthermore, when the total solid content of the molding resin composition is 100 mass %, the content of the inorganic filler is preferably 93 mass % or less, more preferably 91 mass % or less, and still more preferably 90 mass % or less. If the content of the inorganic filler is less than the above-mentioned upper limit, the obtained molding resin composition will have good fluidity and good formability. Therefore, the production stability of the sealed structure becomes higher, and a structure excellent in the balance between productivity and durability can be obtained.

Furthermore, when silica such as molten crushed silica, fused spherical silica, and crystalline silica is used as the inorganic filler, the total inorganic filler of the molding resin composition is 100% by mass. , the content of silica is preferably 40 mass% or more, more preferably 60 mass% or more, and further preferably 75 mass% or more. When the content of silica is equal to or higher than the above-mentioned lower limit, the curability and fluidity of the molding resin composition when transferred to the injection mold will be well balanced. In addition, the upper limit of the silica content at this time is not particularly limited, but when the total inorganic filler of the molding resin composition is 100 mass %, it is, for example, 100 mass % or less.

Furthermore, when inorganic fillers are used in combination with metal hydroxides such as aluminum hydroxide and magnesium hydroxide as described below, or inorganic flame retardants such as zinc borate, zinc molybdate, and antimony trioxide, these inorganic flame retardants The total amount of the agent and the above-mentioned inorganic filler is desirably set within the content range of the above-mentioned inorganic filler.

[Other ingredients] In addition to the above-mentioned components, the molding resin composition of this embodiment may contain other components such as adhesion aids, waxes, coupling agents, colorants, flame retardants, release agents, and low-stress agents as necessary.

(Adhesive agent) In order to improve the curability at low temperatures, the molding resin composition of this embodiment preferably contains an adhesion aid. The adhesion aid used in the molding resin composition of this embodiment is not particularly limited, and examples thereof include triazole compounds. Examples of the triazole compounds include those having 1,2,4-triazole. Compounds with azole rings and compounds with 1,2,3-triazole rings. Specific compounds include, for example, 3-amino-1,2,4-triazole, 4-amino-1,2,3-triazole, and 3-amino-1,2,4-triazole. Azole-5-carboxylic acid, 3-mercapto-1,2,4-triazole, 4-mercapto-1,2,3-triazole, 3,5-diamino-1,2,4-triazole, 3,5-dimercapto-1,2,4-triazole, 4,5-dimercapto-1,2,3-triazole, 3-amino-5-mercapto-1,2,4-triazole, 4-Amino-5-mercapto-1,2,3-triazole, 3-hydrazino-4-amino-5-mercapto-1,2,4-triazole and 5-mercapto-1,2,4 -Triazole-3-methanol, etc., one type of these can be used, or two or more types can be used in combination. Among these, compounds having at least one mercapto group are preferred.

The lower limit of the content of the adhesion aid in the molding resin composition of the present embodiment is preferably 0.01 mass % or more, and more preferably 0.01 mass % or more when the total solid content of the molding resin composition is 100 mass %. Preferably, it is 0.05 mass % or more, More preferably, it is 0.07 mass % or more. This can further improve the hardenability at low temperatures. Moreover, as an upper limit of the content of the adhesion aid, for example, when the total solid content of the molding resin composition is 100 mass %, it is preferably 10 mass % or less, more preferably 5 mass % or less, and still more preferably The content is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.3% by mass or less. Thereby, it is possible to improve the adhesiveness and waterproofness when sealing structures such as electronic components and stators with the molding resin composition of this embodiment.

(wax) The molding resin composition of this embodiment preferably contains wax with a melting point of 30°C to 90°C. By containing such a wax, the molding resin composition has good meltability at the temperature used in the transfer mold, thereby improving fluidity during sealing and improving filling properties. Examples of such waxes include natural waxes such as carnauba wax, synthetic waxes such as beocyanate wax and oxidized polyethylene wax, and higher fatty acids such as zinc stearate and metal salts thereof.

When the total solid content of the molding resin composition is 100 mass %, the blending amount of wax is, for example, 0.05 mass % or more and 2.0 mass % or less. When the total solid content of the molding resin composition is 100 mass %, the lower limit of the blending amount of wax is preferably 0.1 mass % or more, more preferably 0.2 mass % or more. When the total solid content of the molding resin composition is 100% by mass, the upper limit of the amount of wax blended is preferably 1.5% by mass or less, more preferably 1.0% by mass or less. By blending the coupling agent wax within the above range, the obtained molding resin composition has excellent fluidity and filling properties when transferred to the injection mold.

(coupling agent) In order to improve the adhesiveness between the epoxy resin and the inorganic filler, the molding resin composition of this embodiment may contain a coupling agent such as a silane coupling agent. Examples of the coupling agent include epoxysilane, aminosilane, ureidosilane, and mercaptosilane.

Examples of epoxysilane include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-glycidoxypropylmethyl Dimethoxysilane, β-(3,4 epoxycyclohexyl)ethyltrimethoxysilane, etc. Examples of the aminosilane include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-β(aminoethyl)γ-aminopropyltrimethoxysilane. , N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, N-phenylγ-aminopropyltriethoxysilane, N-phenylγ-aminopropyltrimethoxysilane , N-β(aminoethyl)γ-aminopropyltriethoxysilane, N-6-(aminohexyl)3-aminopropyltrimethoxysilane, N-(3-(trimethoxysilyl) Propyl)-1,3-phenylenedimethane, etc. Examples of ureidosilane include γ-ureidopropyltriethoxysilane, hexamethyldisilazane, etc. They can be used as A potential aminosilane coupling agent that reacts with a ketone or an aldehyde to protect the primary amine group site of an aminosilane. The aminosilane may have a secondary amino group. The mercaptosilane may include, for example, a γ-mercapto group. In addition to propyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane, bis(3-triethoxysilylpropyl)tetrasulfide and bis(3-triethoxysilane) Silane coupling agents that exhibit the same function as mercaptosilane coupling agents through thermal decomposition, such as silylpropyl disulfide, etc. In addition, these silane coupling agents can be blended with those obtained by hydrolysis reaction in advance. One type of silane coupling agent may be used alone, or two or more types may be used in combination.

In terms of connection formability, mercaptosilane is preferred, in terms of fluidity, aminosilane is preferred, and in terms of adhesiveness, epoxysilane is preferred.

The lower limit of the content of coupling agents such as silane coupling agents in the molding resin composition of the present embodiment is preferably 0.01 mass % or more when the total solid content of the molding resin composition is 100 mass %. More preferably, it is 0.05 mass % or more, still more preferably 0.1 mass % or more, still more preferably 0.2 mass % or more. If the content of a coupling agent such as a silane coupling agent is more than the above-mentioned lower limit, the interface strength between the epoxy resin and the inorganic filler material will not decrease, and the adhesiveness and waterproofness when sealing structures such as electronic parts and stators can be improved. . In addition, the upper limit of the content of a coupling agent such as a silane coupling agent is preferably 1 mass % or less, more preferably 0.8 mass % or less when the total solid content of the molding resin composition is 100 mass %. The content is preferably 0.6 mass% or less, and further preferably 0.4 mass% or less. If the content of a coupling agent such as a silane coupling agent is less than the above-mentioned upper limit, the interface strength between the epoxy resin and the inorganic filler material will not decrease, and the adhesiveness and waterproofness when sealing structures such as electronic parts and stators can be improved. . In addition, when the content of the coupling agent such as the silane coupling agent is not more than the above-mentioned upper limit, it is possible to prevent the cured product of the molding resin composition from increasing in water absorbency.

[characteristic] For the molding resin composition of this embodiment, the lower limit of the glass transition temperature (Tg) measured by the following (Method 1) is preferably 140°C or higher, more preferably 150°C or higher, and still more preferably 155°C. or above, more preferably 160°C or more, further preferably 165°C or more. Since the glass transition temperature (Tg) is equal to or higher than the above lower limit, the molding resin composition of the present embodiment can be cured even at low temperatures. In addition, the heat resistance of the cured product of the molding resin composition of the present embodiment is get improved. Moreover, the upper limit of the glass transition temperature (Tg) is not particularly limited, but is, for example, 300°C or lower, 250°C or lower, or 220°C or lower.

(method 1) Using a transfer molding machine, mold the resin composition for molding into a test piece of 80 mm × 10 mm × 4 mm under the conditions of a mold temperature of 175°C, an injection pressure of 6.9MPa, and a curing time of 90 seconds, and then heat it at 175°C for 2 hours. Post hardening is performed. Furthermore, a thermal mechanical analysis device was used to measure the thermal expansion coefficient of the test piece obtained at a temperature rising rate of 5° C./min. Next, based on the obtained measurement results, the glass transition temperature (Tg) (℃) of the hardened material is calculated from the inflection point of the thermal expansion coefficient.

Here, the hardened material for measuring the glass transition temperature is obtained by hardening the resin composition at 175° C. for 2 hours, for example. Specifically, the glass transition temperature Tg can be calculated based on the measurement results obtained by, for example, post-hardening the test piece at 175° C. for 2 hours, and then using a thermomechanical analysis device to set the temperature range of the test piece to 0. ℃ ~ 320 ℃, the temperature rise rate is 5 ℃ / minute, the test piece was measured using a low-pressure transfer molding machine with a mold temperature of 175 ℃, an injection pressure of 6.9MPa, and a hardening time of 90 seconds. It is obtained by injecting and molding the resin composition under certain conditions. As a low-pressure transfer molding machine, for example, KTS-15 and KTS-30 (manufactured by KOHTAKI Corporation) can be used. Moreover, as a thermomechanical analysis device, for example, TMA/SS6000 (manufactured by Seiko Instruments Inc.) or TMA7100 (manufactured by Hitachi High-Tech Science Corporation) or the like can be used.

For the molding resin composition of this embodiment, let S ₁ be the spiral flow measured under the conditions of a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a curing time of 3 minutes. After being left at 25°C for 48 hours, when the spiral flow measured under the conditions of mold temperature 175°C, injection pressure 9.8MPa, and hardening time 3 minutes is set to S ₂ , it is better to satisfy S ₂ ≥ 0.8 × S ₁ . In this way, it can be cured at a low temperature, thereby improving the adhesion and waterproofness when sealing structures such as electronic parts and stators. In addition, it can also improve long-term storage properties.

For the molding resin composition of this embodiment, the upper limit of the time for the torque value to reach 2 N·m measured by the following (Method 2) is preferably less than 100 seconds, more preferably less than 70 seconds, and still more preferably not more than 100 seconds. Up to 50 seconds, and preferably less than 30 seconds. Since the time required for the torque value to reach 2 N·m does not reach the above-mentioned upper limit, the molding resin composition of this embodiment can be molded even at low temperature. In addition, the lower limit value of the time required for the torque value to reach 2N·m is not particularly limited, but may be, for example, 0.1 second or more or 1 second or more.

(Method 2) Using a hardener (registered trademark), the torque value of the molding resin composition was measured over time under the conditions of a mold temperature of 140°C and an amplitude angle of ±0.25 degrees. Based on the measurement results, calculate the time (seconds) for the torque value to reach 2N·m from the beginning of measurement.

As the hardener (registered trademark), for example, hardener (registered trademark) MODEL7 (manufactured by A&D Company, Limited) or the like can be used.

For the molding resin composition of this embodiment, the spiral flow measured by the following (Method 3) is preferably 70 cm or more, more preferably 80 cm or more, and still more preferably 90 cm or more. When the spiral flow is equal to or higher than the above-mentioned lower limit, the tightness and waterproofness when sealing structures such as electronic components and stators can be further improved. In addition, the spiral flow is preferably 180 cm or less, more preferably 160 cm or less, further preferably 140 cm or less. By keeping the spiral flow below the above upper limit, the long-term storage stability of the molding resin composition of this embodiment can be improved.

(Method 3) Use a low-pressure transfer molding machine to inject the resin composition for molding into a spiral flow measurement mold in accordance with ANSI/ASTM D 3123-72 at 175°C, an injection pressure of 6.9MPa, and a holding time of 3 minutes, and measure Flow length, set it to spiral flow (cm).

As a low-pressure transfer molding machine, for example, the above-described KTS-15 and KTS-30 (manufactured by KOHTAKI Corporation) can be used.

For the molding resin composition of this embodiment, the gelling time measured by the following (Method 4) is preferably 30 seconds or more, more preferably 40 seconds or more, and still more preferably 50 seconds or more. By setting the gelling time to be equal to or greater than the above lower limit, the long-term storage stability of the molding resin composition of the present embodiment can be improved. Moreover, the gelation time is preferably 80 seconds or less, more preferably 70 seconds or less, and still more preferably 60 seconds or less. When the gelling time is equal to or less than the above upper limit, the adhesiveness and waterproofness when sealing structures such as electronic components and stators can be further improved.

(Method 4) Use a low-pressure transfer molding machine to inject the resin composition for molding into the spiral flow measurement mold in accordance with ANSI/ASTM D 3123-72 at 175°C, an injection pressure of 6.9MPa, and a holding time of 3 minutes. The time from the start of injection to the time when the molding resin composition hardens and stops flowing is measured as the gelling time (seconds).

As a low-pressure transfer molding machine, for example, the above-described KTS-15 and KTS-30 (manufactured by KOHTAKI Corporation) can be used.

For the molding resin composition of this embodiment, the lower limit of the linear expansion coefficient α1 measured by the following (Method 5) is not particularly limited, but is, for example, 0.8 ppm/°C or more, 1.0 ppm/°C or more, or 1.2 ppm. /℃ or above. Moreover, the linear expansion coefficient α1 is preferably 10.0 ppm/°C or less, more preferably 5.0 ppm/°C or less, further preferably 3.0 ppm/°C or less, still more preferably 2.0 ppm/°C or less. When the linear expansion coefficient α1 is equal to or less than the above-mentioned upper limit, the adhesiveness and waterproofness when sealing structures such as electronic components and stators can be further improved.

(Method 5) Using a low-pressure transfer molding machine, the molding resin composition was injected and molded under the conditions of a mold temperature of 175°C, an injection pressure of 9.8MPa, and a curing time of 3 minutes to obtain a molded product of 15 mm × 4 mm × 4 mm. Next, the obtained molded article was post-hardened at 175° C. for 4 hours to prepare a test piece. Thereafter, for the obtained test piece, a thermomechanical analysis device was used to measure the average linear expansion coefficient α1 at 25-70°C under the conditions of a measurement temperature range of 0°C to 400°C and a temperature rise rate of 5°C/min. (ppm/℃).

As a low-pressure transfer molding machine, for example, the above-described KTS-15 and KTS-30 (manufactured by KOHTAKI Corporation) can be used. Moreover, as a thermomechanical analysis device, for example, the above-mentioned TMA/SS6000 (manufactured by Seiko Instruments Inc.) or TMA7100 (manufactured by Hitachi High-Tech Science Corporation) can be used.

The thermal conductivity of the molding resin composition of this embodiment measured by the following (Method 6) is preferably 0.5 W/m·K or more, more preferably 0.6 W/m·K or more, and still more preferably 0.7 W. /m·K or more, and more preferably 0.8W/m·K or more. When the thermal conductivity is equal to or higher than the above-mentioned lower limit, the heat associated with the electronic components inside the molded body using the molding resin composition of the present embodiment can be efficiently released. Moreover, the thermal conductivity is preferably 3.5 W/m·K or less, more preferably 3.3 W/m·K or less, further preferably 3.1 W/m·K or less, further preferably 2.9 W/m·K or less, Furthermore, it is more preferable that it is 2.8W/m·K or less. When the thermal conductivity is equal to or less than the above-mentioned upper limit, the influence of heat from the outside on the electronic components inside the molded body using the molding resin composition of the present embodiment can be suppressed.

(Method 6) Using a transfer molding machine, the molding resin composition was injected and molded under the conditions of a mold temperature of 175°C, an injection pressure of 6.9MPa, and a curing time of 90 seconds to obtain a molded body of 80 mm × 10 mm × 4 mm. Next, the obtained molded body was post-hardened at 175° C. for 2 hours to obtain a test piece. The thermal diffusivity of the obtained test piece was measured using the laser flash method. Furthermore, an electronic hydrometer was used to measure the specific gravity of the test piece used for thermal conductivity measurement. Furthermore, a differential scanning calorimeter was used to measure the specific heat of the test piece for thermal conductivity and specific gravity measurement. Based on the measured values of thermal diffusivity, specific gravity, and specific heat, calculate the thermal conductivity (W/m·K) of the test piece in the thickness direction.

As a transfer molding machine, for example, the above-described KTS-15 and KTS-30 (manufactured by KOHTAKI Corporation) can be used. In the measurement of thermal diffusivity by the laser flash method, for example, xenon flash analyzer LFA447 (manufactured by NETZSCH) can be used. Moreover, as an electronic hydrometer, for example, SD-200L (manufactured by Alfa Mirage Co., Ltd.) or the like can be used. Moreover, as a differential scanning calorimeter, for example, DSC8230 (manufactured by Rigaku Corporation) or the like can be used.

[use] The molding resin composition of this embodiment is used to seal together a substrate mounted with electronic components, a stator core having a plurality of grooves formed in the circumferential direction and fixed to the substrate, and a plurality of coils housed in the grooves. A stator having the molding resin composition of this embodiment as a sealing material is applied to an electric motor (motor), for example, as a rotating electrical machine (electric motor, generator, or electric motor/generator combined machine).

＜Sealing structure＞ Hereinafter, the sealing structure 200 using the molding resin composition of this embodiment will be described using drawings. FIG. 1 schematically shows a plan view of the sealed body 100 and the sealing structure 200 before and after molding. Similarly, FIG. 2 schematically shows a side view of the sealed body 100 and the sealing structure 200 before and after molding. Here, (a) and (c) schematically show the sealed body 100 before molding, and (b) and (d) schematically show the sealing structure 200 after molding.

The sealing structure 200 in this embodiment includes a sealed body 100, a substrate 10 on which electronic components 11 are mounted, and a stator core 20 fixed on one surface of the substrate 10 and having a plurality of grooves 21 formed along the circumferential direction. , and a plurality of coils 30 accommodated in the groove 21; and a sealing member 50 provided to cover part or all of the sealed body 100. The sealing member 50 is composed of a cured product of the molding resin composition of this embodiment.

In the sealing structure 200 of this embodiment, the sealed body 100 sealed with the molding resin composition of this embodiment includes: a substrate 10 on which electronic components 11 are mounted; and a stator core 20 fixed on one surface of the substrate 10. And it has a plurality of grooves 21 formed along the circumferential direction; and a plurality of coils 30 accommodated in the grooves 21 .

As shown in FIG. 1 , the substrate 10 is, for example, a substrate on which electronic components 11 are mounted on one or both of one surface and another surface opposite to the one surface. As shown in FIG. 1 , the substrate 10 has a flat plate shape, for example.

For example, the substrate 10 may have a solder resist layer on one surface on which the electronic components 11 are mounted. The above-mentioned solder resist layer can be formed using a resin composition for forming a solder resist generally used in the field of semiconductor devices. In this embodiment, for example, a solder resist layer can be provided on one surface and the other surface of the substrate 10 . The solder resist layer provided on one surface or both of the one surface and the other surface of the substrate 10 is formed of, for example, a resin composition containing a polysiloxy compound. This makes it possible to realize a solder resist layer with excellent surface smoothness.

As shown in FIG. 1( a ), the electronic components 11 are respectively mounted on one surface and the other surface of the substrate 10 , for example. On the other hand, the electronic component 11 may be provided only on one surface of the substrate 10 but not on the other surface of the substrate 10 . Examples of the electronic component 11 include light-emitting elements such as LED chips, biological measuring instruments that detect biological potentials such as brain waves/myopotentials, or biological activities such as blood pressure/pulse, and biological measuring instruments that detect pressure/temperature/position/humidity/light/sound/ General measuring instruments such as acceleration and other environmental information, mobile power supplies such as capacitors, acoustic modules, communication modules and other components, and wiring connecting the above components, etc.

Here, it is preferable that the lead wire 40 is connected to the substrate 10 and the electronic component 11 . Before sealing with the molding resin composition of this embodiment, the lead wire 40 is connected to the substrate 10 and the electronic component 11, whereby the connection portion between the lead wire 40, the substrate 10, and the electronic component 11 can be sealed once by the sealing member 50 described later. As a result, the waterproofness of the sealing structure 200 of this embodiment can be improved.

As shown in FIG. 1( a ), the stator core 20 is provided with a plurality of grooves 21 formed along the circumferential direction when viewed from the axial end. Here, as shown in FIG. 1(a) , four grooves 21 are provided. Thereafter, as shown in FIG. 2( c ), the stator core 20 is fixed on one surface of the substrate 10 on which the electronic component 11 is mounted. The stator core 20 may be provided by laminating a plurality of electromagnetic steel plates along the axial direction and closely fixing them, or may be provided by molding a resin composition.

The coil 30 has, for example, a flat wire U-shape, and is wound so as to be accommodated in two separate grooves 21 . The coil 30 has a first coil end and a second coil end. The first coil end protrudes toward one axial direction side of the stator core 20 . The second coil end protrudes toward the other axial side of the stator core 20 . That is, the coil 30 has a pair of coil ends respectively protruding toward both sides of the stator core 20 in the axial direction.

As shown in FIGS. 1(b) and 2(d) , the sealing member 50 fixes the substrate 10 on which the electronic component 11 is mounted on one surface of the substrate 10 and has a plurality of grooves formed along the circumferential direction. The stator core 20 of 21 and the plurality of coils 30 accommodated in the slot 21 are sealed at once. That is, the sealing member 50 is provided to cover part or all of the sealed body 100. The sealed body 100 includes: a substrate 10 on which electronic components 11 are mounted; and a stator core 20 fixed on one surface of the substrate 10 and having an edge along the base plate 10. A plurality of grooves 21 are formed in the circumferential direction; and a plurality of coils 30 are received in the grooves 21 . As a material of the sealing member 50, the above-mentioned molding resin composition is used.

At this time, as shown in FIGS. 1( b ) and 2 ( d ), the connection portions between the preferred lead 40 , the substrate 10 and the electronic component 11 are once sealed by the sealing member 50 . In this way, the waterproofness of the sealing structure 200 of this embodiment can be improved.

＜Manufacturing method of sealed structure＞ Hereinafter, a method of manufacturing a sealing structure using the molding resin composition of this embodiment will be described. The manufacturing method of the sealed structure of this embodiment includes the following steps: arranging a substrate loaded with electronic components in a mold of a transfer molding machine, a stator core having a plurality of grooves formed along the circumferential direction and fixed to the substrate; A plurality of coils accommodated in the above-mentioned grooves; and the above-mentioned substrate, the above-mentioned stator core and the above-mentioned coils in the above-mentioned mold are sealed and molded with the molding resin composition of this embodiment by the transfer molding method using the above-mentioned transfer molding machine. , thereby obtaining a sealed structure.

The above-mentioned step of obtaining the above-mentioned sealed structure is performed, for example, at a temperature of 80° C. or higher and less than 180° C. and a pressure of 1 MPa or higher and 15 MPa or lower. Preferably, the above steps are carried out at a temperature of 120°C to 170°C and a pressure of 3MPa to 12MPa. Thereby, a sealing structure excellent in adhesion and waterproofness can be obtained. In this case, the above-mentioned step of obtaining the above-mentioned sealed structure is preferably performed at a temperature below the Tg of the cured body of the molding resin composition.

The above-mentioned steps of obtaining the above-mentioned sealed structure may include: (A) Molding steps by transfer molding, compression molding, etc.; and (B) After the forming step, the formed body is heated and then hardened.

In a general sealing step, after the above (A), the epoxy resin is hardened, and the above (B) is performed for the purpose of obtaining a good cross-linked structure. On the other hand, in a preferred aspect of this embodiment, the post-hardening step (B) is not performed and only the molding step (A) is performed. In this way, productivity is improved, thermal damage caused by post-hardening, that is, thermal damage to the stator core, coils and substrates to be sealed can be suppressed, and a good sealed structure can be obtained. In this embodiment, the molding resin composition is configured so that "the bending elastic modulus at 25°C (according to JIS K6911:2006) of the cured product obtained by curing at 140°C for 2 minutes is 0.1GPa or more and 30GPa or less." material, so even if (B) is omitted, a good cross-linked structure can be obtained.

Furthermore, in this embodiment, the molding temperature in (A) is preferably a temperature not higher than Tg (°C) of the cured body obtained from the molding resin composition, more preferably not higher than (Tg-10°C), and most preferably Preferably (Tg-30℃) or less. Moreover, the molding temperature is preferably 160°C or lower, more preferably 140°C or lower, most preferably 130°C or lower. By molding at such a low temperature, thermal damage to the stator core, coils and substrates to be sealed can be suppressed, and a good sealed structure can be obtained. The lower limit of the molding temperature is not particularly limited as long as the resin composition for molding can be sufficiently hardened. For example, it can be set to (Tg-80°C) or higher, and it can be set to 90°C or higher.

When the post-hardening of (B) is performed, the post-hardening temperature is preferably in the same range as the above-mentioned molding temperature. That is, the temperature is preferably set to a temperature not higher than Tg (°C) of the cured body obtained from the molding resin composition, more preferably not higher than (Tg-10°C), most preferably not higher than (Tg-30°C). Moreover, the molding temperature is preferably 160°C or lower, more preferably 140°C or lower, most preferably 130°C or lower. By performing post-hardening at such a low temperature, thermal damage to the sealing object can be suppressed, and a good sealing structure can be obtained. The lower limit of the molding temperature is not particularly limited, but it can be, for example, (Tg-80°C) or higher, or 90°C or higher.

In a general sealing step, the temperature of the above (A) or the above (B) is generally set to a temperature exceeding the Tg (°C) of the cured body obtained from the molding resin composition. On the other hand, in this embodiment, the temperature range of the low-temperature range mentioned above is preferable. In this embodiment, the molding resin composition is configured so that "the bending elastic modulus at 25°C (according to JIS K6911:2006) of the cured product obtained by curing at 140°C for 2 minutes is 0.1GPa or more and 30GPa or less." Therefore, even if the temperature of the above (A) or the above (B) is set to a low temperature, a good cross-linked structure can be obtained.

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

Hereinafter, the present invention will be described based on Examples and Comparative Examples, but the present invention is not limited to these.

(Example 1 to Example 4, Comparative Example 1 to Comparative Example 2) <Preparation of resin composition for molding> For each Example and each Comparative Example, a molding resin composition was prepared in the following manner. First, the ingredients shown in Table 1 were mixed with a mixer. Next, the obtained mixture was rolled and kneaded, and then cooled and pulverized to obtain a molding resin composition as a powdery or granular body.

The details of each component in Table 1 are as follows. In addition, the prescription shown in Table 1 shows the content (mass %) of each component with respect to the whole resin composition.

(Inorganic filler material) •Inorganic filler material 1: Molten spherical silica (manufactured by Denka Company Limited, product name "FB-950") •Inorganic filler material 2: Molten spherical silica (manufactured by Denka Company Limited, product name "FB-105") •Inorganic filler material 3: Alumina (manufactured by Denka Company Limited, product name "DAW-02")

(coupling agent) •Coupling agent 1: N-phenyl-3-aminopropyltrimethoxysilane (manufactured by Dow Corning Toray Co., Ltd., product name "CF-4083")

(epoxy resin) •Epoxy resin 1: o-cresol novolak type epoxy resin (manufactured by DIC CORPORATION, product name "EPICRON N-670")

(hardener) •Hardening agent 1: Phenol aralkyl type resin containing biextended phenyl skeleton (manufactured by MEIWA PLASTIC INDUSTRIES, LTD., product name "MEH-7851SS") •Hardening agent 2: Triphenylmethane type phenol novolac resin (manufactured by MEIWA PLASTIC INDUSTRIES, LTD., product name "MEH-7500")

(Adhesive agent) •Adhesive agent 1: 3-amino-1,2,4-triazole

(hardening catalyst) •Harding catalyst 1: 2-phenylimidazole •Harding catalyst 2: 2-phenyl-4,5-dihydroxymethylimidazole

(coloring material) •Coloring material 1: Carbon black (manufactured by Mitsubishi Chemical Corporation, product name "Carbon#5")

<Performance evaluation of resin compositions for molding> The following items were evaluated about the obtained molding resin composition. The evaluation results are shown in Table 1 below.

(flexural elastic modulus) Using a low-pressure transfer molding machine (KTS-30 manufactured by KOHTAKI Corporation), the resin composition was injected and molded under the conditions of a mold temperature of 140°C, an injection pressure of 9.8MPa, and a curing time of 2 minutes, and a length of 80 mm was obtained. , a molded object with a width of 10mm and a thickness of 4mm. The obtained molded article was heat-treated at 200° C. for 4 hours for post-hardening and set as a test piece, and the flexural elastic modulus (GPa) was measured at an ambient temperature of 25° C. in accordance with JIS K 6911:2006.

(low temperature formability) Using a hardener (registered trademark) (manufactured by A&D Company, Limited, hardener (registered trademark) MODEL 7), the composition of the obtained molding resin was measured over time under the conditions of a mold temperature of 140°C and an amplitude angle of ±0.25 degrees. torque value of the object. Based on the measurement results, calculate the time (seconds) for the torque value to reach 2N·m from the beginning of the measurement. The low-temperature formability was evaluated according to the following standards based on the time (second) for the torque value to reach 2N·m. A: The time for the torque value to reach 2N·m does not reach 30 seconds (this is the case in the embodiment) B: The time for the torque value to reach 2N·m is more than 30 seconds and less than 100 seconds C: The time for the torque value to reach 2N·m is more than 100 seconds

(tightness/waterproofness) For a 23mmφ×0.9mm glass epoxy substrate (the substrate on which the IC package and the aluminum electrolytic capacitor are mounted), use a low-pressure transfer molding machine (KTS-30, manufactured by KOHTAKI Corporation) at a mold temperature of 140°C and an injection pressure of 3 ~5MPa and a curing time of 2 minutes, the resin composition was injection-molded on the substrate to a thickness of 2cm without post-hardening, and a substrate sealing body was obtained. Thereafter, the above-mentioned substrate sealing body is immersed in a pure water pool with a depth of 15 to 100 cm for 1000 hours. Thereafter, after natural drying, the continuity of the circuit wiring on the substrate was confirmed using a testing machine. A: There is no poor conduction B: There is poor conduction (short circuit, increased resistance, etc.)

(spiral flow/gelling time) A low-pressure transfer molding machine (manufactured by KOHTAKI Corporation, "KTS-15") was used in a spiral flow measurement mold in accordance with ANSI/ASTM D 3123-72 at 175°C, an injection pressure of 6.9MPa, and a holding time of 3 minutes. The molding resin compositions of each Example and each Comparative Example were injected under the conditions, and the flow length was measured and set as a spiral flow (cm). In addition, the time from the start of injection to the time when the molding resin composition hardens and stops flowing is measured as the gelling time (seconds). In addition, spiral flow is a parameter of fluidity. The larger the value, the better the fluidity.

(Linear expansion coefficient α1) For each Example and each Comparative Example, the linear expansion coefficient of the obtained molding resin composition was measured. Using a low-pressure transfer molding machine ("KTS-30" manufactured by KOHTAKI Corporation), injection molding was performed under the conditions of a mold temperature of 175°C, an injection pressure of 9.8MPa, and a curing time of 3 minutes, and a 15 mm × 4 mm × 4 mm piece was obtained. Molded products. Next, the obtained molded article was post-hardened at 175° C. for 4 hours to prepare a test piece. Thereafter, the obtained test piece was measured using a thermomechanical analysis device (TMA100, manufactured by Seiko Instruments Inc.) under the conditions of a measurement temperature range of 0°C to 400°C and a temperature rise rate of 5°C/min. Average linear expansion coefficient α1 (ppm/℃) at 25-70℃.

(Glass transition temperature (Tg)) The glass transition temperature of the molding resin composition of each Example and each Comparative Example was measured in accordance with JISK 6911:2006. That is, for the molding resin compositions of each Example and each Comparative Example, a transfer molding machine (manufactured by KOHTAKI Corporation, "KTS-15") was used, and the mold temperature was 175°C, the injection pressure was 6.9MPa, and the curing time was Under the condition of 90 seconds, a test piece of 80mm×10mm×4mm was formed. Thereafter, post-hardening was performed at 175° C. for 2 hours. Furthermore, using a thermomechanical analysis device (TMA/SS6000 manufactured by Seiko Instruments Inc.), the thermal expansion coefficient of the test piece obtained at a temperature rising rate of 5° C./min was measured. Next, based on the obtained measurement results, the glass transition temperature (Tg) (℃) of the hardened material is calculated from the inflection point of the thermal expansion coefficient.

(Thermal conductivity) For the molding resin compositions of each example and each comparative example, a transfer molding machine (manufactured by KOHTAKI Corporation, "KTS-15") was used, and the mold temperature was 175°C, the injection pressure was 6.9MPa, and the curing time was 90 seconds. Injection molding under the conditions, a molded body of 80mm×10mm×4mm was obtained. Next, the obtained molded body was post-hardened at 175°C for 2 hours to obtain a test piece. The thermal diffusivity of the obtained test piece was measured using the laser flash method (xenon flash analyzer LFA447 manufactured by NETZSCH). Furthermore, the specific gravity of the test piece used in the thermal conductivity measurement was measured using electronic hydrometer SD-200L manufactured by Alfa Mirage Co., Ltd. Furthermore, the specific heat of the test piece used for the thermal conductivity and specific gravity measurement was measured using a differential scanning calorimeter DSC8230 manufactured by Rigaku Corporation. Based on the measured values of thermal diffusivity, specific gravity, and specific heat, the thermal conductivity (W/m·K) in the thickness direction of the test piece is calculated.

(Room Temperature Storage Properties) The room temperature storage properties of the molding resin compositions of each Example and each Comparative Example were measured. Using a low-pressure transfer molding machine ("KTS-30" manufactured by KOHTAKI Corporation), the molding materials of each example and each comparative example were injected under the conditions of a mold temperature of 175°C, an injection pressure of 9.8MPa, and a curing time of 3 minutes. For the resin composition, the flow length was measured, and the spiral flow at this time was set to S ₁ . In addition, after the molding resin compositions of each Example and each Comparative Example were left at 25° C. for 48 hours, the flow length was measured under the same conditions as above, and the spiral flow at this time was designated as S ₂ . The above-mentioned S ₁ and S ₂ were evaluated based on the following standards. A: Satisfies S ₂ ≥0.8×S ₁ . B: Satisfies S ₂ <0.8×S ₁ .

[Table 1] Example 1 Example 2 Example 3 Comparative example 1 blend Inorganic filler materials 1 78.0 39.0 Inorganic filler material 2 39.0 Inorganic filler material 3 86.3 91.0 Coupling agent 1 0.3 0.3 0.3 0.3 Epoxy resin 1 12.7 7.5 12.7 4.4 Hardener 1 3.1 1.9 3.1 1.2 Hardener 2 4.3 2.4 4.3 1.5 Sealing aid 1 0.1 0.1 0.1 0.1 hardening catalyst 1 0.2 0.2 0.2 0.2 hardening catalyst 2 1.0 1.0 1.0 1.0 coloring material 1 0.3 0.3 0.3 0.3 total 100.0 108.3 100.0 100.0 physical properties Flexural modulus of elasticity at 25°C [GPa] 14.5 20.0 16.0 30.5 Evaluation Low temperature formability A A A C Tightness/water resistance A A A B Spiral flow [cm] 125 100 110 50 Gel time [sec] 55 55 55 55 Linear expansion coefficient α1[ppm/℃] 1.4 1.4 1.5 1.0 Glass transition temperature (Tg) [℃] 170 170 170 170 Thermal conductivity [W/m·K] 0.8 2.7 1.0 3.0 room temperature storage A A A A

The molding resin compositions of the Examples can be cured at low temperatures and have excellent adhesion and waterproof properties when sealing structures such as electronic parts and stators.

This application claims priority based on Japanese Application No. 2022-058500 filed on March 31, 2022, and the entire disclosure of the application is incorporated herein by reference.

10:Substrate 11: Electronic parts 20:Stator core 21:Slot 30: coil 40:lead 50:Sealing component 100: Sealed body 200: Sealed structure

[Fig. 1] is a plan view of the sealed body and the sealing structure before and after molding in an example of this embodiment. [Fig. 2] is a side view of the sealed body and the sealing structure before and after molding in an example of this embodiment.

10:Substrate

11: Electronic parts

20:Stator core

21:Slot

30: coil

40:lead

50:Sealing component

100: Sealed body

200: Sealed structure

Claims (19)

A molding resin composition for once sealing a substrate mounted with electronic components, a stator core having a plurality of grooves formed along the circumferential direction and fixed on the substrate, and a plurality of coils housed in the grooves, contain: epoxy resin; One or both of a hardener and a hardening catalyst; and inorganic filler materials, The molding resin composition is cured at 140° C. for 2 minutes, and the cured product has a bending elastic modulus at 25° C. (according to JIS K6911:2006) of 0.1 GPa or more and 30 GPa or less. The molding resin composition of claim 1, wherein, The glass transition temperature (Tg) measured by the following (method 1) is 140°C or more and 300°C or less, (method 1) Using a transfer molding machine, the aforementioned resin composition for molding was molded into a test piece of 80 mm × 10 mm × 4 mm under the conditions of a mold temperature of 175°C, an injection pressure of 6.9 MPa, and a curing time of 90 seconds, and the test piece was heated at 175°C for 2 Post-hardening is performed for several hours, and the thermal expansion coefficient of the test piece obtained at a temperature rise rate of 5°C/min is measured using a thermomechanical analysis device. Then, based on the obtained measurement results, the thermal expansion coefficient of the hardened product is calculated from the inflection point. Glass transition temperature (Tg) (°C). The molding resin composition of claim 1 or 2, wherein, The epoxy resin contains one or more types selected from the group consisting of a phenol novolak type epoxy resin, a cresol novolak type epoxy resin, and a trisphenolmethane type epoxy resin. The molding resin composition of claim 1 or 2, wherein, When the total solid content of the molding resin composition is 100% by mass, the content of the epoxy resin is 3% by mass or more and 40% by mass or less. The molding resin composition according to claim 1 or 2, which contains the aforementioned hardener, and the aforementioned hardener contains a phenolic resin-based hardener. The molding resin composition of claim 5, wherein, The phenol resin hardener contains one or more types selected from the group consisting of phenol novolak resin, cresol novolac resin, naphthol novolac resin and trisphenolmethane type phenol resin. The molding resin composition of claim 5, wherein, When the total solid content of the molding resin composition is 100% by mass, the content of the curing agent is 0.8% by mass or more and 12% by mass or less. A molding resin composition according to claim 1 or 2, which contains the curing catalyst, and the curing catalyst contains an imidazole compound. The molding resin composition of claim 8, wherein, When the total solid content of the molding resin composition is 100% by mass, the content of the curing catalyst is 0.01% by mass or more and 2.0% by mass or less. The molding resin composition according to Claim 1 or 2, wherein the spiral flow obtained by measuring the molding resin composition under the conditions of a mold temperature of 175°C, an injection pressure of 9.8MPa, and a curing time of 3 minutes is set to S ₁ , after the molding resin composition is left at 25°C for 48 hours, the spiral flow measured under the conditions of mold temperature 175°C, injection pressure 9.8MPa, and hardening time 3 minutes is set to S ₂ , It satisfies S ₂ ≥0.8×S ₁ . The molding resin composition of claim 1 or 2, wherein, The time for the torque value measured by the following (Method 2) to reach 2N·m does not reach 100 seconds. (Method 2) Use a CURELASTOMETER to measure the torque value of the aforementioned molding resin composition over time under the conditions of a mold temperature of 140°C and an amplitude angle of ±0.25 degrees. Based on the measurement results, calculate the torque value to reach 2N·m from the beginning of the measurement. time (seconds). The molding resin composition of claim 1 or 2, wherein, The spiral flow measured by the following (method 3) is more than 70cm, (Method 3) Use a low-pressure transfer molding machine to inject the aforementioned molding resin composition into a spiral flow measurement mold in accordance with ANSI/ASTM D 3123-72 at 175°C, an injection pressure of 6.9MPa, and a holding time of 3 minutes. Measure the flow length and set it as spiral flow (cm). The molding resin composition of claim 1 or 2, wherein, The gelling time measured by the following (method 4) is more than 30 seconds, (Method 4) Use a low-pressure transfer molding machine to inject the aforementioned molding resin composition into the spiral flow measurement mold in accordance with ANSI/ASTM D 3123-72 at 175°C, an injection pressure of 6.9MPa, and a holding time of 3 minutes. The time from the start of injection to the time when the molding resin composition hardens and stops flowing is measured as the gelling time (seconds). The molding resin composition of claim 1 or 2, wherein, The linear expansion coefficient α1 measured by the following (method 5) is 10.0ppm/℃ or less, (Method 5) Using a low-pressure transfer molding machine, under the conditions of a mold temperature of 175°C, an injection pressure of 9.8MPa, and a curing time of 3 minutes, the aforementioned resin composition for molding was injected and molded to obtain a molded product of 15 mm × 4 mm × 4 mm, and then , the obtained molded article was post-hardened at 175°C for 4 hours to prepare a test piece. Thereafter, the obtained test piece was measured using a thermomechanical analysis device at a temperature ranging from 0°C to 400°C. , under the condition that the heating rate is 5℃/min, measure the average linear expansion coefficient α1 (ppm/℃) at 25-70℃. The molding resin composition of claim 1 or 2, wherein, The thermal conductivity measured by the following (Method 6) is above 0.5W/m·K, (Method 6) Using a transfer molding machine, under the conditions of a mold temperature of 175°C, an injection pressure of 6.9MPa, and a curing time of 90 seconds, the aforementioned resin composition for molding was injected and molded to obtain a molded body of 80 mm × 10 mm × 4 mm, and then , the obtained molded body was post-hardened at 175°C for 2 hours to obtain a test piece. The thermal diffusivity of the obtained test piece was measured using the laser flash method and an electronic hydrometer was used. The specific gravity of the test piece used for thermal conductivity measurement is then measured using a differential scanning calorimeter. The specific heat of the test piece used for thermal conductivity and specific gravity measurement is calculated based on the measured values of thermal diffusivity, specific gravity and specific heat. Thermal conductivity in the thickness direction of the test piece (W/m·K). A method of manufacturing a sealed structure, which includes the following steps: The molding die in the transfer molding machine is configured with a substrate loaded with electronic components, a stator core having a plurality of grooves formed along the circumferential direction and fixed on the substrate, and a plurality of coils accommodated in the grooves; and Sealing is obtained by sealing and molding the substrate, the stator core and the coil in the molding mold with the molding resin composition according to any one of claims 1 to 15 using the transfer molding method of the transfer molding machine. Structure. The manufacturing method of a sealed structure as claimed in claim 16, wherein: In the step before obtaining the sealed structure, sealing molding is performed at a temperature equal to or lower than Tg of the cured body of the molding resin composition. The manufacturing method of a sealed structure as claimed in claim 16 or 17, wherein: As the aforementioned step before obtaining the aforementioned sealing structure, the post-hardening step is not performed. A sealing structure, which is provided with a sealed body and a sealing member, The aforementioned sealed body includes A substrate loaded with electronic components, a stator core fixed on one surface of the aforementioned base plate and having a plurality of slots formed along the circumferential direction, and A plurality of coils received in the aforementioned slot; The sealing member is provided to cover part or all of the sealed body, The sealing member is composed of a cured product of the molding resin composition according to any one of claims 1 to 15.

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