JPS6014497B2 - porcelain capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a porcelain condenser that can be stably used for long periods of time even in sulfur hexafluoride (SF6) gas.

In recent years, circuit breakers using SF6 gas as an arc-extinguishing medium have been used as high-power circuit breakers.
When two interrupting parts are connected in series, a capacitor is used to equalize the torque applied to each.

Conventionally, a plastic capacitor or an oil-immersed paper capacitor is used as this capacitor, and these capacitors are attached to the outside of the circuit breaker. It is desirable to downsize the circuit breaker as described above, and this objective can be achieved by downsizing the capacitor and placing the capacitor inside the circuit breaker. In order to miniaturize the capacitor, barium titanate (base Tj03), which has a higher specific electrical conductivity than the plastic or paper capacitors mentioned above, is used.
Alternatively, a so-called magnetic capacitor using a dielectric material such as strontium titanate (SrTi03) may be used, but such a magnetic capacitor is
It has the disadvantage that it is eroded in 6 gases and its insulation resistance decreases in an extremely short period of time. To explain this in detail, SF6 gas itself is non-corrosive, but SF8 gas generates gases such as SF4, SOF4, SOF2, etc. in the presence of moisture, and these gases further become SQ in the presence of moisture.
F2, HF, etc. are generated, and the ceramic capacitors are corroded by these gases, and the insulation resistance decreases in an extremely short period of time, making them unusable. The present invention has been made to eliminate this drawback, and the present inventors have proposed that the above object can be achieved by forming a film of a specific organic polymer compound on the surface of a ceramic capacitor. discovered. The present invention is based on this discovery, which will be explained in more detail below. An example of the structure of the above magnetic capacitor is shown in FIGS. 1 and 2.

FIG. 1 is a plan view thereof, and FIG. 2 is a cross-sectional view taken along line A-A' of the capacitor shown in FIG. 1, showing the porcelain dielectric material, its surface resin coating, and one metal. 1 is a ceramic dielectric, 2 is an electrode, 3 is a metal terminal, 4 is a solder layer connecting the electrode 2 and the metal terminal 3, and 5 is an organic polymer compound (resin) formed on the surface of the capacitor. It is a film.

The present invention, as described above, forms a film of an organic polymer compound with a thickness of 0.01 to 1 on the surface of a ceramic capacitor, and the organic polymer compound used in the present invention is , cycloaliphatic epoxy resin, bisphenol epoxy resin, polyptadiene resin, and fluororesin, specific examples of which are shown below. Examples of the cycloaliphatic epoxy resin include 3,4-epoxy-6-methylcyclohexylmethyl-4-epoxy-6-methylcyclohexane carpoxylate, and 3,4-epoxycyclohexylmethyl-(3,4-epoxy)cyclohexane carpoxylate. xylate, 4-(1,2-epoxyethyl)-1,
Examples include 2-epoxycyclohexane,
Commercially available products include CY-179 (manufactured by Ciba, Switzerland).
Product name) is one example.

As the bisphenol-based epoxy resin, 2,2-bis[p-(2,3-epoxypropoxy)phenyl]-propane can be mentioned, and the above-mentioned Araldite (trade name) manufactured by Ciba Co., Ltd., manufactured by Shell Oil Company. 1001 (product name)
etc. are bisphenol-based epoxy resins. As the polybutadiene resin, polybutadiene obtained by anionic polymerization is used, and a commercially available product is JSR-ABS-53 (trade name) manufactured by Japan Synthetic Rubber Co., Ltd.

Examples of fluororesins include polytrifluoroethylene, polytetrafluoroethylene, polyhexafluoropropylene, tetrafluoroethylene-hexafluoropropylene copolymer, trifluorochloroethylene-vinylidene fluoride copolymer, hexafluoropropylene- Examples include pinylidene fluoride copolymers.

In the present invention, the ceramic dielectric has a relative dielectric constant of 1.0.
BaTi03-SrTi0 with 00 to 10,000
3-, Bi203・3ri02 and mother Ti03-Bi
2 (SN02)3 was used.

A specific example is shown below.

Example 1 As a ceramic capacitor, the material is BaTi03-SrTi
03-Bi203.3ri02 (relative dielectric constant 1520), having the shape shown in Figure 1, diameter 4 arcs, thickness 2
I used the one from Gaga.

Among the bisphenol-based epoxy resins mentioned above, 2,2-pis[p-(2,3-epoxypropoxy)phenyl]-propane (Shell Oil Company Ship.1001) was used as the resin for forming the film, and resin 3. For parts by weight,
Add 10 parts by weight of ethyl methyl ketone as a solvent,
A film-forming solution containing about 30% solids was prepared. After immersing the above-mentioned porcelain capacitor into this liquid, the capacitor was pulled up to form a liquid film on the surface of the capacitor.
The capacitor was heated in air at 0° C. for 20 minutes to evaporate the solvent and form an epoxy resin film on the surface of the capacitor. The thickness of the coating was approximately 0.2 mm. A ceramic capacitor with an epoxy resin film formed in this way was used in a circuit breaker containing SF6 gas, and the decrease in insulation resistance was investigated.
Even after using the bait for 00 hours, it showed a resistance of 1 and MQ or more, and no decrease was observed. Further, as an epoxy resin, one of the above-mentioned cycloaliphatic epoxy resins, 3
,4-epoxy6-methylcyclohexylmethyl-4
- Epoxy 6-methylcyclohexane carboxylate was selected, and the same ceramic capacitor as above was immersed in it, then taken out and heated at 160° C. for 3 hours to form a film of the resin on the surface of the capacitor. The thickness of the coating was 0.2 skin. Furthermore, one of the polybutadiene resins, polybutadiene obtained by anion (JSR-A-53 manufactured by Japan Synthetic Rubber Co., Ltd.), was used as the resin, and 8 parts by weight of styrene monomer were mixed with 10 parts by weight of polybutadiene. After immersing the same porcelain capacitor as above, it was pulled out and heated at 150° C. for 1 hour to form a polybutadiene resin coating on the surface of the capacitor.

When a film was formed using a cycloaliphatic epoxy resin and a polybutadiene resin, the same tests as in the case of the bisphael/epoxy resin were conducted, and almost the same results were obtained.

Example 2 As a ceramic capacitor, the material is mother Ti03-Bi2 (S
2) A material having a dielectric constant of 3 (relative permittivity: 2450), having the shape shown in FIG. 1, and having a diameter of 4 and a thickness of 2 arcs was used.

As the resin for forming the film, fine powder of polytetrafluorethylene, which is one of the fluorine resins mentioned above, is used. After applying this fine powder to the surface of the capacitor, it is heated to 400 qo for 5 minutes to form the fluororesin. A film was formed on the surface of the capacitor. The thickness of the coating was about 1 foot. The porcelain capacitor on which the fluororesin film was formed as described above was used in a circuit breaker containing SF6 gas in the same manner as in Example 1, and a durability test was conducted for 200 days at 10 KV AC. No decrease in insulation resistance was observed, and the resistance was higher than 1 MO.

Note that similar results were obtained when polyhexafluoroethylene was used instead of polytetrafluoroethylene.

If the thickness of the above-mentioned resin film is 31, then S
Although it was found that corrosion by F6 gas can be prevented, a thin coating is not desirable in view of mechanical impact, and a thick coating of one skin or more is not desirable because it may cause cracks or peeling due to temperature changes. do not have. The thickness of the coating is 0.0
One willow or one rib is preferred. As mentioned above, the thickness of any of cycloaliphatic epoxy resin, bisphenol epoxy resin, polybutadiene resin, and fluororesin is 0.
．． A ceramic capacitor having a coating of 01 to 1 ribs formed on its surface can be stably used semi-permanently in a circuit breaker containing SF6 gas.

[Brief explanation of the drawing]

1 and 2 are a plan view and a partial cross-sectional view, respectively, showing the shape of a ceramic capacitor used in the present invention and the state in which a resin film is formed on its surface. 1...Porcelain dielectric, 2...Electrode, 3.
...Metal terminal, 4...Solder layer, 5...
...Resin coating. Figure 1 Figure 2

Claims (1)

[Claims] 1. On the surface of the ceramic capacitor, at least one resin selected from cycloaliphatic epoxy resin, bisphenol epoxy resin, polybutadiene resin, and fluororesin is coated with a thickness of 0.
．． A ceramic capacitor characterized by forming a film with a thickness of 0.01 to 1 mm.