JP3502751B2 - Method for producing resin composite - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electric parts used for preventing overcurrent of electric equipment and electric circuits and for preventing ignition and fire due to heat generation, that is, thermostats, temperature fuses, temperature switches, current fuses, fuses. The present invention relates to safety device parts used for resistors, varistors, thermistors, arresters, circuit protectors, breakers, etc. and a method for manufacturing the same.

[0002]

2. Description of the Related Art Electrically insulating parts used in places where an arc is generated, such as safety equipment parts used in electric equipment and electric circuit parts, are made flame-retardant in consideration of heat resistance and ignition safety. The resin used is. However, thermosetting resins other than phenol resins are relatively expensive, and thermoplastic resins have the drawback that they undergo thermal deformation when the temperature rises abnormally, and their shapes cannot be retained.

Further, when a high voltage is applied to these resins, the surface of the resin is carbonized and a conductive path is generated, and a tracking phenomenon occurs in which a current flows along this conductive path. There is a problem that not only the insulation cannot be maintained but also Joule heat is generated.

For example, a general phenolic resin has a heat resistant temperature of around 150 ° C. to 180 ° C. and a tracking resistance (C
Since TI) is 150 to 175V, the use is limited depending on its use. Usually, in a safety device component such as a thermostat that prevents overheating and controls temperature, it is necessary to expand the operating temperature range in order to expand its application. However, there is a limit to the heat resistant temperature of resin, and when it is used at a higher temperature, ceramic parts are used. However, manufacturing such parts from ceramics not only increases the cost, but also lowers the thermal shock resistance compared to resin products, and for some kinds of parts,
There is a problem that the shape is limited.

Further, conventionally, in consideration of heat resistance and ignition safety, a flame-retardant phenol resin molding material containing asbestos fibers has been used for the purpose of enhancing flame retardancy. However, in recent years, as the carcinogenicity of asbestos has been attracting attention and the regulations are becoming more and more stringent, the use of asbestos is regulated due to work environment problems.
A resin material having arc resistance and tracking resistance is desired.

Further, by adding glass fiber to the resin filler, arc resistance and tracking resistance can be improved to some extent, but the conventional injection molding method has a limitation in the compounding ratio. That is, when mixed in a large amount, the flowability of the resin is lowered, the moldability is deteriorated, and at the same time, the cost of the glass fiber affects the raw material cost in addition to the abrasion of the mold, and the raw material becomes too expensive. was there.

Further, the flame-retardant phenol resin molding material has a limit in arc resistance and tracking resistance, and in the case of an electric insulator exposed to high temperature for a long time, a high degree of tracking resistance is required. It could not be used for electrical parts. Further, it is generally known that when an inorganic hydrate is used as a filler, flame retardancy is improved, but there is a problem that heat resistance and mechanical strength are significantly lowered and it is not practical.

Therefore, it has been proposed to mix various fillers with thermosetting resins, particularly phenolic resins, to improve tracking resistance (Japanese Patent Publication No. 57-61).
290, JP-B-64-2423, JP-A-49-10.
4197, JP-A-64-79252, etc.).

[0009]

However, if a large amount of high-cost filler is blended, the material cost becomes high and it becomes impractical. Further, mixing a large amount of the filler impairs the fluidity of the resin, and in ordinary injection molding, there is a drawback that the moldability deteriorates.

In addition, even if a large amount of filler is mixed, there is a drawback in that if the particle size of the filler is not appropriate, the expected effects such as tracking resistance are not obtained.

Generally, a resin material used in various electric devices must have not only a supporting material for an electric component and a structural material but also a function of electrically insulating them. In particular, in recent years, there is a strong demand for flame retardancy in order to prevent the occurrence of fire from electric parts. The causes of ignition from electrical parts are
Ignition due to insulation breakdown or tracking breakdown, and the ignitability of the resin after ignition may be considered. Furthermore, with the enforcement of the PL Law, awareness of safety is increasing,
There is an increasing demand for safety of safety equipment parts, especially for ignition safety. At present, the electrical characteristics of resins are being improved, but with respect to heat resistance and tracking resistance, we have not been able to fully meet the demands, and at present the improvement of the characteristics is strongly desired. is there.

[0012]

SUMMARY OF THE INVENTION Therefore, the present invention provides 70-
A resin composite comprising 30% by volume of resin and 30 to 70% by volume of filler, wherein the filler has an average particle size of 3 μm.
It is characterized by containing a water-containing inorganic compound of m or less.

That is, by containing a hydrous inorganic compound as a filler, when a high voltage is applied to form a carbonized conductive path, the water of crystallization in the hydrous inorganic compound is released and the carbonized conductive path is blocked. Therefore, the tracking resistance can be improved.

In the present invention, a thermosetting resin or a photocurable resin is mixed with a filler containing a water-containing inorganic compound,
The present invention is characterized by a method for producing a resin composite, which comprises a step of press-molding this mixed raw material at room temperature, and then releasing from the mold and heat-curing or photo-curing.

That is, the moldability can be improved by uniformly mixing the resin and the filler powder containing the water-containing inorganic compound and subjecting to powder pressure molding. Therefore, as compared with the injection molding method, the mixing ratio of the filler such as ceramics can be increased up to 70% by volume ratio, whereby the deflection temperature under load (heat resistance) is 200 to 250 ° C., and the tracking resistance (CTI) is 250 V. As described above, a resin composite having excellent heat resistance can be obtained.

Further, 70 to 30% by volume of thermosetting resin,
The reason why the filler content is 30 to 70% by volume is that when the resin content is 70% by volume or more, the deformation during heat curing is large, the dimensional accuracy cannot be maintained, and the heat resistance, that is, the deflection temperature under load, becomes low. Further, if the content is 30% by volume or less, powder pressure molding becomes difficult.

Further, the water-containing inorganic compound is an inorganic compound containing water of crystallization, specifically, aluminum hydroxide (Al (OH) ₃ ) and magnesium hydroxide (Mg).
(OH) ₂ ), zeolite or the like is used.

The reason why the average particle size of these hydrated inorganic compounds is 3 μm or less is that the expected effect of improving the tracking resistance cannot be obtained when the average particle size exceeds 3 μm.
This is because, as described above, the hydrated inorganic compound releases crystal water at a certain temperature to block the carbonization conductive path,
This has the effect of improving the tracking resistance, but if the average particle size is too large, the heat resistance decreases and the effect of improving the tracking resistance decreases.

In the resin composite of the present invention, all of the filler components may be composed of the above-mentioned hydrated inorganic compound or a mixture of the hydrated inorganic compound and other fillers. In this case, it is preferable to use ceramics as the other filler. Specifically, alumina (Al ₂ O ₃ ), silica (SiO ₂ ), steatite (MgO · SiO ₂ ), forsterite (2MgO · SiO ₂ ), mullite (3Al ₂ O ₃ · 2)
SiO ₂ ), cordierite (3MgO · 2Al ₂ O ₃ ·
5SiO ₂ ) or the like is used. The average particle size of these ceramics is also preferably 5 μm or less.

As other fillers, known fillers such as clay, talc, mica, kaolin, silica sand, calcium carbonate, glass fiber and the like may be appropriately blended.

Regarding the average particle size of the above-mentioned hydrated inorganic compound and other fillers, an arbitrary surface or cross section of the resin composite is analyzed by an image analysis device, and the circle equivalent of the filler particles such as ceramics present on this surface is analyzed. It can be measured by calculating the average value of the diameter.

Further, if the particle size of the filler containing these hydrated inorganic compounds becomes small, the dispersibility may be deteriorated when mixed with the resin in some cases, so that the surface of the filler powder is modified. Alternatively, the surface of the coupling agent may be coated.

As the thermosetting resin constituting the resin composite of the present invention, various types such as epoxy type, phenol type, melanin type and polyester type can be used, but the phenol type resin is most suitable. . Further, as the photocurable resin, an ultraviolet curable resin or the like can be used.

The resin composite of the present invention may further contain known curing agents, curing aids, lubricants, plasticizers, dispersants, colorants, release agents and other known additives, if necessary. There is no problem even if added in a small amount so that there is no problem in practical use.

Further, in the filler component of the present invention, Cl, P, Na, Al, Si, Sr,
In some cases, Mg, Zr, Fe, Co, Cu, Ta, etc. may be contained, and even if these are mixed in about 0.1 wt% in the total amount, there is no problem in characteristics. In addition, a metal element or the like may be mixed in an extremely small amount due to the manufacturing process.

Next, in the manufacturing method of the present invention, the method of adding a filler such as ceramics to the thermosetting resin is not particularly limited, and a known method can be adopted. For example, a method of mixing the mixture with a thermosetting resin with a mixer, kneading with a Brabender, and then pulverizing, or a method of melting and kneading the mixture with a heating roll and then pulverizing, etc. may be mentioned. Further, if necessary, it may be granulated to a predetermined particle size and used for molding.

Further, in the heat curing step, the mold is released from the mold, and the heat treatment is performed at a temperature in the range of 80 to 250 ° C. according to the properties of the thermosetting resin and the compounding amount of ceramics. A mold jig may be used in the heat treatment depending on the case. Further, the present invention is characterized in that various devices or electric parts are arranged in a case made of the above resin composite to constitute a safety device part.

That is, as described above, by constructing a safety device part using a resin composite having a high deflection temperature under load and a high tracking resistance, it is possible to maintain the insulation even when a high voltage is applied without being deformed even at a high temperature. Since it can be maintained well, it is possible to obtain a safety device component that can be favorably used in various applications.

In the present invention, the safety equipment parts are electric parts and parts used for preventing overcurrent of an electric circuit, ignition due to abnormal heat generation, and fire. , Thermostat, thermal fuse, thermal switch, current fuse, fuse resistor, varistor,
Means a thermistor, arrester, circuit protector, breaker, etc.

[0030]

The present invention will be described in the following examples.

Phenol novolac resin is used as the thermosetting resin, and aluminum hydroxide powder and magnesium hydroxide powder having an average particle size of 5 μm or less are prepared as fillers, and these are weighed so that the compounding ratios shown in Tables 1 to 3 are obtained. ,
Mix, then powder press mold this mixture at room temperature,
A heat treatment was performed at 80 to 250 ° C. to obtain a test piece that was heat cured.

The deflection temperature under load and the tracking resistance of the thus obtained sample were measured. Here, the deflection temperature under load is a temperature at which the resin composite having a predetermined shape begins to deform when the temperature is increased while applying a load, and was measured by the method of JIS K 7207. If the deflection temperature under load is 150 ° C. or higher, it can be suitably used as a safety device component.

Regarding tracking resistance, IE
It was measured based on the C Pub112 method. That is, it is the voltage at which two electrodes are arranged in a resin composite of a predetermined shape, an AC voltage is applied between them, and an electrolytic solution is dropped onto the resin composite between both electrodes to cause dielectric breakdown. If the tracking resistance (CTI) is 250 V or more, it can be suitably used as a safety device part.

The results are shown in Tables 1-3. According to this result, when the average particle diameter of the water-containing inorganic compound such as aluminum hydroxide exceeds 3 μm, the tracking resistance is 250.
It can be seen that the deflection temperature under load becomes low when V does not reach V and the compounding amount of the thermosetting resin exceeds 70% by volume.

On the other hand, the examples of the present invention containing the filler containing the hydrous inorganic compound having an average particle size of 3 μm or less in the range of 30 to 70% by volume have a tracking resistance of 250 V or more and a deflection temperature under load of 200 ° C. or more, Excellent results are shown.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

As described above in detail, according to the present invention, 7
A resin composite comprising 0 to 30% by volume of a resin and 30 to 70% by volume of a filler, wherein the filler contains a water-containing inorganic compound having an average particle size of 3 μm or less, thereby improving tracking resistance and heat resistance. Therefore, it can be suitably used for various purposes.

Further, according to the present invention, 70 to 30% by volume of a thermosetting resin or a photocurable resin is mixed with 30 to 70% by volume of a filler containing a hydrous inorganic compound, and the mixed raw material is brought to room temperature. The resin composite can be manufactured with high accuracy in an extremely simple process by the process of pressure-molding and press-molding, and then releasing from the mold and heat-curing or photo-curing.

Further, according to the present invention, various devices or electric parts are arranged in the case made of the above resin composite to constitute a safety equipment part, so that the case has excellent tracking resistance and heat resistance. Therefore, it can be satisfactorily used even in an environment where high temperature or high voltage is applied.

Claims (2)

(57) [Claims] 1. A thermosetting resin or a photocurable resin is used in an amount of 70 to 70%.
Filler 30 to 7 containing 30% by volume and hydrous inorganic compound
0 volume% is mixed, this mixed raw material is pressure-molded at room temperature, and then, the resin composite is manufactured by releasing from the mold and heat-curing or photo-curing. 2. The method for producing a resin composite according to claim 1, wherein the hydrated inorganic compound has an average particle diameter of 3 μm or less.