JP3485200B2 - Electronic components with thermal fuse - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component having a thermal fuse in which a thermal fuse is provided inside or outside.
The present invention relates to an electronic component, such as a power transformer, which is partially or entirely covered with a resin, including at least a thermal fuse. 2. Description of the Related Art When an accident occurs in an electronic component such as a power transformer, the electronic component is liable to be directly linked to a disaster such as a fire or an electric shock. A thermal fuse is attached as a protection circuit when the voltage is abnormally increased. Electronic components with thermal fuses have a built-in or exposed thermal fuse and are packaged.In order to protect the electronic circuit from external impact and ensure insulation, the entire component or a part including the thermal fuse is required. , Coated with a synthetic resin. In selecting this coating material, it is necessary to consider that the electronic components generate heat and that the thermal fuse has poor physical characteristics.
First, it can be used continuously at high temperatures, and second, it does not cause the thermal fuse to be blown or degraded by the filling temperature or filling pressure of the resin during coating.
Required as an absolute requirement. Conventionally, as this coating material, a thermosetting resin represented by an epoxy resin having a high heat resistance and a low filling temperature and a low filling pressure has been exclusively used. [0003] An electronic component coated with a thermosetting resin satisfies all of heat resistance, impact resistance, and electrical insulation, and has no functional problem. However, when a thermosetting resin is coated by using a transfer molding method or the like, it is difficult to cure the resin in a short time with the current technology, so that the molding cycle time becomes extremely long, and the yield becomes poor. It causes the cost to rise. In addition, used electronic parts are all disposed of in a lump since effective treatment methods for thermosetting resins have not been established, but in recent years that treatment method has become a problem,
A rational solution is desired. SUMMARY OF THE INVENTION The present invention is directed to an electronic component with a thermal fuse that efficiently solves the above-mentioned problems, and has a structure in which a part or the whole of the electronic component including the thermal fuse is included. 215 ° C. or less. [0005] The polyester resin used in the present invention comprises:
The melting point is not particularly limited as long as the melting point is 215 ° C. or less, but preferably, the modified polyalkylene terephthalate resin, that is, terephthalic acid or its ester-forming derivative and C 2
A copolymer comprising, as a main component, a polyalkylene terephthalate, polyethylene terephthalate, polypropylene terephthalate or polybutylene terephthalate obtained by subjecting a polycondensation reaction to alkylene glycols or ester-forming derivatives thereof to a copolymer having other comonomer units introduced therein. It is. Here, the content of the comonomer unit is not particularly limited as long as the copolymer can have fluidity, heat resistance, and a low melting point (at 215 ° C. or lower), which are basic characteristics as an engineering plastic. Examples of the third component (comonomer) constituting such a copolymer include isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylethanedicarboxylic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, and dodecanediacid. Examples thereof include known dicarboxylic acids and their alkyl, alkoxy, and halogen-substituted products. These dicarboxylic acid compounds can be used for polycondensation in the form of a derivative capable of forming an ester, for example, a lower alcohol ester such as dimethyl ester, and can be introduced as a copolymer component. On the other hand, as the dihydroxy compound used as the third component for constituting the copolymer,
Ethylene glycol, propanediol, butanediol, diethylene glycol, triethylene glycol,
Relatively low molecular weight dihydroxy compounds such as neopentyl glycol, hydroquinone, resorcinol, dihydroxyphenyl, naphthalene diol, dihydroxydiphenyl ether, cyclohexanediol, 2,2-bis (4-hydroxyphenyl) propane, diethoxylated bisphenol A, and these Examples thereof include an alkyl, alkoxy, or halogen-substituted product. In the present invention, a polyalkylene terephthalate resin produced by polycondensation using the above compound as a third component can be used alone or as a mixture of two or more. Among them, aromatic dicarboxylic acid-modified polyalkylene terephthalate copolymer or alkylene glycol-modified polyalkylene terephthalate copolymer has fluidity, heat resistance, and low melting point, which are the basic characteristics of engineering plastics. It can be suitably used to achieve the object of the invention, and among them, isophthalic acid-modified polybutylene terephthalate copolymer or ethylene glycol-modified polybutylene terephthalate copolymer can be particularly preferably used. The intrinsic viscosity of the polyester resin used in the present invention measured in orthochlorophenol at 25 ° C. is preferably 1.0 dl / g or less, more preferably 0.8 dl / g or less. If the intrinsic viscosity of the polyester resin is too high, the fluidity deteriorates, the filling pressure must be increased during injection molding, and the thermal fuse attached to the electronic component tends to be damaged, which is not preferable. Further, a thermoplastic polyester modified by a method such as known crosslinking, graft polymerization,
Alternatively, even if a mixture of other thermoplastic resins and the like in a thermoplastic polyester is used as the base resin depending on the purpose,
The effects of the present invention can be exhibited. Examples of the thermoplastic resin and the like mixed with the thermoplastic polyester include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, polyamide, polyacetal, polystyrene, Styrene-butadiene copolymer, styrene-butadiene-acrylonitrile copolymer, styrene-butadiene-acrylic acid (or ester thereof)
Copolymer, styrene-acrylonitrile copolymer, polycarbonate, polyurethane, fluorine resin, polyphenylene oxide, polyphenylene sulfide, polybutadiene, halogenated polyolefin, polyvinyl halide, butyl rubber, silicone resin, olefin-based thermoplastic elastomer (for example, EPDM or ionomer ), Styrene-based thermoplastic elastomer (for example, SBS
Or SEBS), urethane-based thermoplastic elastomer,
Examples include polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, polyether-based thermoplastic elastomers, multilayer graft copolymers mainly containing polyacrylate, and modified products thereof. These substances are not essential components, and can be appropriately selected and used in accordance with desired properties, and the amount of addition is not particularly limited. In the present invention, mechanical strength, heat resistance,
In order to obtain a molded product excellent in performance such as dimensional stability and electrical properties, it is preferable to add a filler as necessary to the polyester resin, and a fibrous material according to the intended performance.
A powdery or plate-like filler is used. Examples of the fibrous filler include glass fiber, asbestos fiber, carbon fiber, silica fiber, silica / alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, copper, brass, etc. And inorganic fibrous substances such as metallic fibrous materials. In addition, a high melting point organic fibrous substance such as a polyamide and a fluorine resin-like filler can also be used. On the other hand, as a powdery and granular filler,
Carbon black, silica, quartz powder, glass beads,
Glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, diatom salts such as wollastonite, metal oxides such as iron oxide, titanium oxide, zinc oxide and alumina, metal carbonates such as calcium carbonate and magnesium carbonate Salt, calcium sulfate, metal sulfate such as barium sulfate, other boron carbide, boron nitride, silicon nitride,
Various metal powders can be mentioned, and as the plate-like filler, mica, glass flake, various metal foils and the like can be mentioned.
These inorganic fillers may be used alone or in combination of two or more. In using these fillers, it is desirable to use a sizing agent or a surface treatment agent as necessary. Further, the polyester resin is added with various substances generally added to the resin depending on the purpose and application, for example, an antioxidant, a release agent, a flame retardant, a flame retardant aid, a crystallization accelerator, a dye, and a pigment. be able to. [0007] Since the polyester resin has excellent electrical properties and moderate hardness and elasticity, the coated electronic parts with thermal fuses have good electric insulation and sufficient impact resistance. You will be satisfied. Further, the polyester resin has good fluidity, and furthermore, its melting point is specified to be 215 ° C. or less.
The filling temperature and the filling pressure can be lowered, the thermal fuse is not blown or broken, and the solidification speed is high, so that the cycle time is very short. Further, the polyester resin can be recycled because it can be re-melted, and has great merits in disposal treatment. The present invention will be described below in detail with reference to the drawings. [Examples 1 and 2] <Production of resin> Dimethyl terephthalate, 1,4-butanediol, and dimethyl isophthalate were copolymerized by an ordinary method to obtain isophthalic acid containing 6 mol% of isophthalic acid residues. Modified polybutylene terephthalate resin (a)
(DMI-modified PBT resin) was obtained. 0.75 intrinsic viscosity
dl / g. The melting point was measured at 215 ° C. by using a DSC-7 differential scanning calorimeter manufactured by Perkin Elmer. <Manufacture of Power Transformer with Thermal Fuse> FIG. 1 shows a power transformer 2 having a built-in thermal fuse 1 having a melting point of 130 ° C., wherein 2a is an iron core and 2b is a winding. The power transformer 2 having the built-in thermal fuse 1 is
As shown in the figure, the DMI-modified PBT (a) was filled with 30% by weight of glass fiber at a resin temperature of 235 ° C. and an injection pressure of 400 kg /.
Injection was performed under the condition of cm ^{2, and} the entire power supply transformer including the thermal fuse 1 was covered with the polyester resin 4 to manufacture the power supply transformer with the thermal fuse of Example 1 (FIG. 3). The time required from the injection of the resin to the curing of the resin (hereinafter referred to as molding cycle time) was 29 seconds. Further, only the injection pressure was changed to 600 kg / cm ² , and the power supply transformer with the thermal fuse of Example 2 was manufactured. The molding cycle time was 29 seconds. Injection molding was repeated under both injection pressure conditions to manufacture ten power fuse-equipped power transformers. <Evaluation of Quality of Manufactured Product> Ten manufactured power transformers with thermal fuses were connected one by one to a tester to check whether the thermal fuse was melted or damaged. The evaluation results are shown in Table 1 together with the molding cycle time. [Examples 3 and 4] <Production of resin> The procedure of Example 1 was repeated except that the amount of dimethyl isophthalate as a comonomer unit was increased.
DMI-modified PBT (b) containing 12.5 mol% of isophthalic acid residues was obtained. The intrinsic viscosity was 0.75 dl / g. The melting point was measured in the same manner as in Example 1, and as a result, it was 205 ° C. <Production of Power Transformer with Thermal Fuse> The resin coating was formed in the same manner as in Example 1 except that the resin to be injection-molded was changed to DMI-modified PBT resin (b) and the injection molding conditions were changed to a resin temperature of 225 ° C. Then, 10 power supply transformers with a thermal fuse of Example 3 were manufactured. Further, in the same manner as in Example 3, only the injection pressure was changed to 600 kg / cm ^2, and ten power supply transformers with thermal fuses of Example 4 were manufactured. The molding cycle time under both injection pressure conditions of 400 kg / cm ² and 600 kg / cm ² was 30 seconds, respectively.
30 seconds. <Quality Evaluation of Manufactured Product> The quality evaluation of the obtained power transformers with thermal fuses of Examples 3 and 4 was performed in the same manner as in Example 1. The evaluation results are shown in Table 1 together with the molding cycle time. Comparative Examples 1 and 2 <Production of Resin> Polybutylene terephthalate resin (c) (PBT resin) was obtained by polymerizing dimethyl terephthalate and 1,4 butanediol by a usual method. The intrinsic viscosity is 0.
It was 75 dl / g. Further, the melting point was measured by the same method as in Example 1, and it was 225 ° C. <Production of Power Transformer with Thermal Fuse> A resin coating was formed in the same manner as in Example 1 except that the resin to be injection-molded was changed to PBT resin (c) and the injection molding conditions were changed to a resin temperature of 245 ° C. Then, ten power supply transformers with a thermal fuse of Comparative Example 1 were manufactured. Further, in the same manner as in Comparative Example 1, only the injection pressure was changed to 600 kg / cm ^2, and ten power supply transformers with thermal fuses of Comparative Example 2 were manufactured. The molding cycle time under both injection pressure conditions of 400 kg / cm ² and 600 kg / cm ² was 29 seconds and 29 seconds, respectively. <Quality Evaluation of Manufactured Product> The quality evaluation of the obtained power transformers with thermal fuses of Comparative Examples 1 and 2 was performed in the same manner as in Example 1. The evaluation results are shown in Table 1 together with the molding cycle time. Comparative Example 3 <Production of Power Transformer with Thermal Fuse> The resin to be injection molded was changed to a commercially available epoxy resin, and the resin temperature was changed to 175.
The entire transformer including the thermal fuse was formed by transfer molding under the molding conditions of a temperature of 90 ° C. and an injection pressure of 90 kg / cm ² , and ten power fuse-equipped power transformers of Comparative Example 3 were manufactured. The molding cycle time was 150 seconds. <Quality Evaluation of Manufactured Product> The quality evaluation of the obtained power transformer with a thermal fuse of Comparative Example 3 was performed in the same manner as in Example 1. The evaluation results are shown in Table 1 together with the molding cycle time. [Table 1] From the quality evaluation result of the manufactured product, the melting point was 215
It can be seen that a power supply transformer with a built-in thermal fuse coated with a DMI-modified PBT resin, which is a polyester resin having a temperature of not more than 100 ° C., can be manufactured in a short molding cycle with a high yield. In the above embodiment, a power transformer incorporating a thermal fuse is described as being covered with resin. However, in addition to the power transformer, electronic parts such as motor coils and solenoids may be covered with resin. In addition to covering the entirety, it is also possible to cover only a part including the sheathed thermal fuse. According to the present invention, there is provided an electronic component having a thermal fuse.
Since electronic components are manufactured using a polyester resin with a specific melting point, the cycle time of resin coating molding during manufacturing can be drastically shortened. Without
High yield can be maintained. For this reason, the manufacturing cost can be reduced as compared with the conventional one, and the productivity can be greatly improved. Further, the coated resin can be re-melted and reused, which can greatly contribute to disposal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a power transformer to which a thermal fuse is attached. FIG. 2 is an explanatory view of a resin coating step. FIG. 3 is an explanatory view of a manufactured electronic component with a thermal fuse. [Explanation of Signs] 1. Thermal fuse, 2. Power transformer, 2a Iron core, 2b Winding, 3. Mold, 4. Polyester resin.

Claims (1)

(57) [Claims 1] An electronic component with a thermal fuse inside or outside of which a thermal fuse is incorporated, wherein a part or the whole of the electronic component including the thermal fuse has a melting point of 215 ° C or less. Temperature coated with polyester resin having
An electronic component having a fuse, wherein the polyester resin is an isomeric component as a comonomer unit.
A modified polyester containing a phthalic acid residue and having an intrinsic viscosity of 1.0 or less.
An electronic component with a thermal fuse, which is a alkylene terephthalate resin .