JPH06170868A - Manufacture of electric appliance - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing electric appliances, excellent in curing property, resistance to crack, heat conductivity, workability and dielectric characteristics. CONSTITUTION:Electric appliances are manufactured by a method wherein a case, receiving the prescribed parts of an electric appliance, is filled with filler having an average particle diameter of 300mum or more, then, thermosetting resin composition is poured under the vacuum degree of 100Torr or less to cure the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electric device, and more particularly to a method for manufacturing an electric device having excellent curability, crack resistance, thermal conductivity, workability and withstand voltage characteristics.

[0002]

2. Description of the Related Art Conventionally, an electric device which has been subjected to an insulation treatment has parts such as coils and circuit parts set in a plastic case or a metal case, and a uniform mixture of a resin and an inorganic filler is injected into the case under atmospheric pressure or vacuum. It is manufactured by the potting method that cures and cures. However, in this method, there is a limit in the amount of the inorganic filler to be mixed from the viewpoint of workability, so that there is a drawback that the product price becomes high. Further, since volume contraction occurs when the resin composition is cured, cracks are generated in the cured product, and peeling or cracks are likely to occur in the built-in coil or other component. Further, since the thermal conductivity is poor, the temperature of the device becomes high, and there is a problem that the temperature to be used is limited. Furthermore, in order to perform the injection work after mixing the resin composition and the inorganic filler and defoaming under vacuum,
It is necessary to use a resin composition with a long curing time, the curing time after injection becomes long, and the work process is rationalized,
There is a limit to energy saving. Recently, as a method for solving the above-mentioned drawbacks, a method of filling a filler in advance and then injecting and curing the resin composition has been studied. According to this method, cracking property, thermal conductivity, work rationalization, etc. can be improved, but there is a problem that it is difficult for the filled filler to be impregnated with the resin composition, and voids are likely to remain in the cured product, resulting in poor withstand voltage characteristics. It was

[0003]

SUMMARY OF THE INVENTION The present invention provides a method for manufacturing an electric device which is free from the above-mentioned drawbacks of the prior art and is excellent in curability, crack resistance, thermal conductivity and insulation characteristics.

[0004]

According to the present invention, an average particle diameter is 300 μm in a case that accommodates predetermined parts of electric equipment.
After filling the above fillers, 1 part of thermosetting resin composition
The present invention relates to a method for manufacturing an electric device, which is characterized by injecting at a vacuum degree of 00 Torr or less and curing.

The average particle size of the filler used in the present invention is 300 μm or more, preferably 600 to 1200 μm. The particle diameter is measured according to JIS Z 2602-1976. If the average particle size is less than 300 μm,
Since the particles are fine and the gaps between the particles are small, unimpregnated portions remain when the urethane resin composition or the epoxy resin composition is injected, the thermal conductivity is lowered, and the insulating property is also impaired. In addition, the filler is unevenly filled between the components, the coefficient of linear expansion of the entire device becomes non-uniform, peeling cracks occur around the coil and components during the heat cycle, and solder cracks occur at the solder joints of the board. . The type of filler is not particularly limited, and for example, silica sand, silica, alumina, hydrated alumina, clay, mica, glass beads, etc. may be used alone or in combination of two or more. These commercial products include Pearl Sand No. 4, Mikawa Sisand V-3 (manufactured by Tochu Co., Ltd.),
GB-B (manufactured by Toshiba Ballotini), AGSCO SI
LICA SAND # 8-12 (made by AGSCO) etc. are mentioned. You may use these together. Further, these fillers are preferably dried at 70 to 600 ° C. for the purpose of dehumidifying and dehydrating.

In the present invention, the filler is a silane coupling agent having an epoxy group, an amino group or a mercapto group, for example, KBM-303, KBM-403,
KBM-503, KBM-603, KBM-803, K
BM-04 (both are Shin-Etsu Silicone brand names), A
You may use it, after surface-treating it with -187, A-1100, A-189 (all are a brand name by Nippon Unica Co., Ltd.). The treatment with the silane coupling agent is performed, for example, by dispersing the filler in an organic solvent, adding the silane coupling agent while stirring the organic solvent, and drying the filler. Alternatively, the filler may be stirred, sprayed with an aqueous solution of a silane coupling agent, and dried. The use ratio of the filler is preferably in the range of 70 to 80% by weight based on the total amount of the filler and the thermosetting resin composition.

The thermosetting resin composition used in the present invention is not particularly limited, but it has excellent curability, high vapor pressure,
A urethane resin composition, an epoxy resin composition, an unsaturated polyester resin composition, a silicone resin composition, and the like, which have less volatile components under vacuum, are preferable. For the polyurethane resin composition, for example, a polyurethane resin obtained by reacting a polyhydroxy compound with a polyisocyanate is used. As the polyhydroxy compound, liquid polybutadiene-based polyol, polyester polyol, polyether polyol, acrylic polyol, castor oil or castor oil transesterification product, tall oil derivative and the like are used. The liquid polybutadiene-based polyol is preferably 1,4-polybutadiene-based polyol having a molecular weight of 700 to 8000, particularly 1000 to 3000.
As this commercial product, for example, the product name Poly bd R
-45HT, R-45M (made by Idemitsu Petrochemical Co., Ltd.), etc. are mentioned. Castor oil is a triglyceride containing ricinoleic acid (1,2-hydroxyoleic acid) as a main component and has a hydroxyl group of about 2.7 in the molecule. Examples of the commercially available product include URIC-H-28, CAO (made by Ito Oil Co., Ltd.) and the like. The castor oil transesterification product is a transesterification product of castor oil and a natural fat or oil having substantially no hydroxyl group, and as a commercially available product thereof, for example, product names URIC Y-403 and URIC H-31 (manufactured by Ito Oil Co., Ltd.) Etc. The urethane resin composition includes
For example, a low molecular weight polyol such as hexanediol, ethylene glycol, diethylene glycol, propylene glycol, octanediol, 2-ethylhexanediol, glycerin, pentaerythritol, and trimethylolpropane can be used together as a diluent. Further, a plasticizer having no hydroxyl group, for example, phthalic acid ester such as dioctyl phthalate, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, phosphoric acid ester and the like can be used in combination.

Examples of polyisocyanates include tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, diphenyl sulfone diisocyanate, triphenylmethane diisocyanate, hexane methylene diisocyanate, 3-isocyanate methyl-3,
5,5-trimethylcyclohexyl isocyanate, 3
-Isocyanate ethyl-3,5,5-trimethylcyclohexyl isocyanate, 3-isocyanate ethyl-3,5,5-triethylcyclohexyl isocyanate, diphenylpropane diisocyanate, phenylene diisocyanate, cyclohexylylene diisocyanate, 3,3'-diisocyanate dipropyl ether,
Polyisocyanates such as triphenylmethane triisocyanate and diphenyl ether-4,4'-diisocyanate, or the above isocyanates are used as phenols, oximes, imides, mercaptans, alcohols,
Those blocked with ε-caprolactam, ethyleneimine, α-pyrrolidone, diethyl malonate, hydrogen sulfite, sodium, boric acid and the like are used. These may be used alone or in combination of two or more. Further, a polymer of diisocyanate, a modified product thereof, or the like can also be used. An example of these is the trade name MR-1.
00, MTL, etc.

The epoxy resin composition used in the present invention is an epoxy resin having at least one epoxy group in one molecule, for example, a bisphenol A type epoxy resin,
Bisphenol F type epoxy resin, Bisphenol AD
Type epoxy resin, polyglycidyl ester of polyhydric alcohol and the like. Although these resins are not particularly limited, those which are liquid at room temperature are preferable, and commercially available products include Epicoat 828 (trade name of Shell Chemical Co., Ltd.) and GY.
-260 (Ciba Geigy product name), DER-331
(Trade name of Dow Chemical Co.) and the like. These can also be used in combination. You may use diethylene glycol monoglycidyl ether, diethylene glycol diglycidyl ether, polypropylene glycol, etc. as a diluent. An acid anhydride and a curing accelerator or an amine compound are used as a curing agent for these epoxy resins.

The acid anhydride is not particularly limited, but those which are liquid at room temperature are preferable, for example, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylendomethylenephthalic acid, dodecenylphthalic anhydride and the like are used. To be Examples of commercially available products include HN-2000 (trade name of Hitachi Chemical Co., Ltd.) and QH-200 (trade name of Nippon Zeon Co., Ltd.). These can also be used in combination.
The compounding amount of the acid anhydride is preferably 50 to 150 parts by weight with respect to 100 parts by weight of the epoxy resin. Examples of acid anhydride curing accelerators include 2-ethyl-4-methylimidazole, 1-cyanoethyl-4-methylimidazole, and 1-cyanoethyl-4-methylimidazole.
Imidazole and its derivatives such as benzyl-2-ethylimidazole, and tertiary amines such as trisdimethylaminophenol and benzenmethylamine are used. Examples of commercially available products include 2E4MZ, 2E4MZ-CN (both are trade names manufactured by Shikoku Kasei Co., Ltd.), and BDMA (trade name manufactured by Kao Co.). The compounding amount of the curing accelerator is preferably 0.1 to 5.0 parts by weight per 100 parts by weight of the acid anhydride.
Examples of the amine compound include aromatic polyamines, modified products thereof, aliphatic polyamines, modified products thereof, bisspirocyclic diamine or derivatives thereof, and for example, an adduct of diaminodiphenylmethane and an epoxy resin is used. Examples of commercially available products include EH-520 (trade name of Asahi Denka Co., Ltd.), EH-551 (trade name of Adeka Co., Ltd.), Ancamine 2007 (manufactured by Anchor Chemical Co., Ltd.) and the like. These can also be used in combination. The blending amount of the amine compound is preferably 5 to 50 parts by weight with respect to 100 parts by weight of the epoxy resin. As the unsaturated polyester resin composition,
For example, an unsaturated polybasic acid or anhydride thereof and an esterification product of a saturated polybasic acid or anhydride thereof and glycols, to which a crosslinking agent such as a vinyl monomer and a peroxide which is a curing agent are added are used. . As the cross-linking agent, those having a high vapor pressure with a small amount of volatile components under vacuum are preferable. As the silicone resin composition, for example, a silicone polymer having a siloxane bond, an alkoxide resin, an acrylic resin, an epoxy resin, a polyester resin,
A compound obtained by adding a curing agent such as peroxide and a curing initiator such as a platinum compound to a compound obtained by copolymerizing or mixing with a thermosetting resin such as urethane resin is used.

The thermosetting resin composition contains a filler such as crystalline silica, fused silica, hydrated alumina, alumina oxide, talc, calcium carbonate, mica, glass beads, magnesium hydroxide and clay in order to improve the properties. You may use. In addition, if necessary, red phosphorus, hexabromobenzene, dibromophenyl glycidyl ether, dibromocresyl glycidyl ether, flame retardants such as antimony trioxide, red iron oxide, ferric oxide, carbon, titanium white, etc. Various additives such as a foaming agent and a silane coupling agent can be blended. In the present invention, the electric device is filled with a filler in a case accommodating components such as elements, substrates, coils, and lead wires, and the thermosetting resin composition is injected into the case at a vacuum degree of 100 Torr or less and cured. Obtained. Vacuum degree is 100 Torr
If it exceeds, the impregnability of the resin composition into the filler decreases,
The thermal conductivity is reduced and the insulation is impaired. As an electric device to which the present invention is applied, a transformer, a solenoid coil, a high voltage transformer, an electromagnetic clutch, a ballast, which houses an electric component or an electronic component in a plastic or metal case,
Examples include electric devices such as modules, igniters, controllers, regulators, and air bag sensors, and electric devices including a circuit board such as a ceramic substrate and a printed circuit board.

[0012]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. The characteristics were evaluated by the methods shown below. (1) Model impregnation rate: A polyethylene beaker having a diameter of 50 mm was filled while vibrating the filler, and then weighed to obtain the weight (W ₀ g) of the filler. Next, the resin composition was injected, and the mixture was left under a reduced pressure of 10 Torr for 10 minutes,
Cured at 80 ° C. for 3 hours. Then, the cured product was taken out from the polyethylene beaker, the weight (W ₁ g) of the filler separated from the cured product without impregnating the lower resin composition was calculated, and the model impregnation rate was calculated from the following equation.

[Equation 1] The model impregnation rate is to determine the rate of impregnation of the resin composition into the filler, and shows that the model impregnation rate is high and the impregnation property is excellent when the filler in the unimpregnated portion is small.

(2) Impregnation into model equipment: A model equipment in which a primary coil, a secondary coil and parts are housed in a metal case is filled with a filler dried at 600 ° C. for 2 hours.
The temperature was lowered to 0 ° C. and filling was performed while shaking. Next, after injecting the resin composition under a reduced pressure of 10 Torr, 10 Torr
The mixture was left standing at r for 3 minutes, returned to normal pressure and cured at 80 ° C. for 6 hours. Then, the obtained model device was cut, and the impregnation state of the coil and the gap between the parts and the impregnation state of the resin composition with the filler were observed and evaluated as follows. ◯: The gap between the coil and the component is impregnated, and the filler is impregnated with the resin composition. B: Some of the unimpregnated portion of the resin composition remains in the filler. X: A considerable amount of unfilled portion of the resin composition remains in the filler. (3) Crack resistance: 1 on a metal dish having a diameter of 60 mm
A 1 / 2-inch iron spring washer was set, and the resin composition was injected to the upper end of the washer and cured to obtain a test piece. After that, remove the metal petri dish and JIS C
A heat cycle test was performed in accordance with the heat cycle conditions of No. 2105, the crack generation state was observed, and the number of cycles in which cracks were generated was shown.

(4) Thermal conductivity: A polyethylene beaker having a diameter of 50 mm was filled with the filler while vibrating. Next, the resin composition was injected, and the mixture was left under a reduced pressure of 10 Torr for 10 minutes, and cured at 80 ° C. under normal pressure for 3 hours.
mm, 10 mm thick disc-shaped test piece was prepared, and the thermal conductivity (cal / c) was measured with a thermal conductivity measuring device (manufactured by Dynatec).
m ・ sec ・ ° C) (5) Dielectric breakdown strength: 600 for a die adjusted to a thickness of 3 mm
The temperature of the filler dried at 70 ° C. for 2 hours was lowered to 70 ° C., and the filler was added while vibrating. Next, the resin composition was added to 10 Torr.
After injecting it under reduced pressure, leave it at 10 Torr for 3 minutes,
The mixture was returned to normal pressure and cured at 80 ° C. for 6 hours. Then, the ball-flat plate electrode was set on the obtained 3 mm-thick resin cured plate, and the breakdown voltage was measured in insulating oil for a short time.

Examples 1 to 10 Fillers ((B), (C), (D), (F) and (H)) shown in Table 1 which were surface-treated with a silane coupling agent.
And the urethane resin composition or the epoxy resin composition prepared by the formulation shown in Table 2 according to the above-mentioned test method, model impregnating property of the resin composition, impregnating property into model equipment, crack resistance, thermal conductivity The dielectric breakdown strength (withstand voltage characteristic) was examined, and the results are shown in Table 2. The surface treatment of the filler was performed by dissolving the silane coupling agent in methanol so as to be 5% by weight, adding the filler to this solution, stirring and mixing, and then removing the solution and drying at 60 ° C. for 5 hours.

[Table 1]

[Table 2] From Table 2, it is shown that, in any of the present examples, the resin composition is excellent in model impregnation property, model impregnation property, crack resistance, thermal conductivity and dielectric breakdown strength.

Comparative Examples 1 to 5 The characteristics were examined in the same manner as in Example 1 except that the fillers (A), (E) and (G) not surface-treated with the silane coupling agent were used. The results are shown in Table 3, and in each case, the withstand voltage characteristics (dielectric breakdown strength) are lowered. Comparative Example 6 In Comparative Example 1, the characteristics were examined in the same manner as in Comparative Example 1 except that the filler (I) having an average particle diameter of 200 μm which was not surface-treated with the silane coupling agent was used.
However, the model impregnation property and the model device impregnation property are significantly reduced. Comparative Example 7 In Comparative Example 1, the characteristics were examined in the same manner as in Comparative Example 1 except that no filler was used, and the results are shown in Table 3.
The crack resistance and thermal conductivity are extremely poor.

[Table 3]

Examples 11 to 19 The filler (J) shown in Table 4 and the filler (K) shown in Table 5 were used, and the urethane resin composition or epoxy resin composition prepared by the formulation shown in Table 6 was used. According to the test method, the model impregnation property of the cured product, the impregnation property into the model equipment, the linear expansion coefficient, the crack resistance, and the thermal conductivity were examined, and the results are shown in Table 6. The linear expansion coefficient was measured as follows. Linear expansion coefficient: A case was filled with a filler dried at 600 ° C. for 2 hours while lowering the temperature to 70 ° C. while vibrating.
Next, after injecting the resin composition under a reduced pressure of 10 Torr,
Leave at 10 Torr for 3 minutes, return to normal pressure and hold at 80 ° C for 6
Allowed to cure for hours. 5 mm x 5 from the resulting cured product
A mm × 2 mm test piece was cut out and the linear expansion coefficient (° C. ⁻¹ ) was measured using a TMA thermophysical tester (manufactured by Rigaku Denki Co., Ltd.).

[Table 4]

[Table 5] From Table 6, in any case of the present example, the model impregnating property,
It is shown that the model equipment has excellent impregnation properties, crack resistance, and thermal conductivity.

[Table 6]

Comparative Examples 8 to 11 In Comparative Examples 8 to 11 in which the filler (J) shown in Table 7 was not used and potting treatment was applied, the linear expansion coefficient was large because the amount of the filler added was small, so crack resistance was high. Inferior, the thermal conductivity was also inferior.

Comparative Example 12 The filler (J) shown in Table 7 has an average particle diameter of 200 μm.
In Comparative Example 12 using fine particles of m, the model impregnation property and the model device impregnation property were significantly reduced.

Comparative Example 13 In Comparative Example 13 in which the thermosetting resin composition was injected into the filler (J) shown in Table 7 at atmospheric pressure, voids were scattered in the cured product, and the model impregnation property and model equipment Impregnating property was lowered.

[Table 7]

[0021]

According to the present invention, the filler in the case is uniformly and sufficiently impregnated with the thermosetting resin composition, and the cured product has no bubbles and adheres well to parts, coils, etc. Similarly, it is possible to obtain an electric device exhibiting excellent impregnation properties and adhesion. Further, in the conventional potting method, from the viewpoint of the injection workability, the use ratio of the resin composition to the filler of 1.0 had a limit of 0.4 in terms of weight ratio. Since the amount can be increased more, the total cost can be reduced, and the curing shrinkage and thermal expansion during curing are small, and the crack resistance, the thermal conductivity of the cured product, and the heat cycle property are improved.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area B29K 105: 16

Claims (2)

[Claims] 1. A thermosetting resin composition is injected and cured at a vacuum degree of 100 Torr or less after a filler having an average particle diameter of 300 μm or more is filled in a case containing a predetermined part of an electric device. A method of manufacturing the characteristic electric equipment. 2. An average particle size of 30 which is surface-treated with a silane coupling agent having an epoxy group, an amino group or a mercapto group in a case containing a predetermined part of an electric device.
A method for manufacturing an electric device, comprising filling a urethane resin composition or an epoxy resin composition at a vacuum degree of 100 Torr or less and curing after filling a filler of 0 μm or more.