JP2010044930A - Arc resistant insulating material and circuit breaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arc resistant insulating material that can prevent internal deterioration due to arc and can prevent wear; and to provide a circuit breaker with a nozzle formed thereof. <P>SOLUTION: The arc resistant insulating material 10 includes a predetermined fluorine resin 20 containing 0.1-1% inorganic ultraviolet shielding material 30 based on the weight of the fluorine resin 20, wherein the shielding material is coated with a white inorganic substance free from discoloration when firing the fluorine resin 20 and heat-resistant and which is free from discoloration when firing the fluorine resin 20 and heat-resistant. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an insulator having excellent arc resistance, and particularly comprises an arc-resistant insulator suitable for use in a circuit breaker in which an arc is generated between electrodes and the arc-resistant insulator. The present invention relates to a circuit breaker provided with a nozzle.

For example, there is a device that generates an arc between electrodes in the device, such as a circuit breaker or an arc chute breaker. The generated arc is extinguished by, for example, blowing a sulfur hexafluoride gas (SF ₆ gas) between the electrodes in the circuit breaker, or the arc chute breaker is applied with a magnetic field by, for example, coils installed on both sides of the electrode. It is turned off by blowing sulfur hexafluoride gas into the area. In these devices, an insulator is installed in the vicinity of the generated arc to protect the components of the device from the heat of the arc and the light containing a large amount of ultraviolet rays.

  Conventionally, unfilled fluorine-based resins that do not contain fillers made of other substances have been used as such shielding insulators. However, when an unfilled fluororesin is used, the resin is decomposed inside the fluororesin due to a large amount of ultraviolet rays generated by an arc at the time of interruption, and conductive carbides are generated. For this reason, there is a problem that the electrical insulation performance is remarkably lowered.

  In addition, the phenomenon that the gas generated by the internal carbonization of the resin is ejected from the inside of the resin toward the resin surface and the fluorine-based resin is blown off occurs, and a remarkable unevenness is formed on the resin surface, which is installed for shielding. There has been a problem that the mechanical strength of the insulator is greatly reduced.

  To solve such problems, a technology is disclosed in which boron nitride (BN) is filled in a fluororesin to reflect light from the arc and prevent light from entering the resin, thereby preventing internal deterioration. (For example, refer to Patent Document 1). This fluororesin is filled with 1% to 10% by weight of boron nitride (BN).

In addition, a technique for adding 0.2 to 5% by weight of an inorganic pigment having a particle diameter of 1 μm or less and / or an organic pigment having a particle diameter of 0.5 μm or less to a polymer insulator is disclosed (for example, Patent Documents). 2). In Patent Document 2, for example, polytetrafluoroethylene resin that needs to be fired at around 300 ° C., an organic pigment having heat resistance of hundreds of degrees, ultramarine blue that gradually changes color at a temperature of 300 ° C. or higher, etc. Filling has been shown.
Japanese Patent No. 2581606 Japanese Examined Patent Publication No. 62-60783

  However, in the conventional fluororesin filled with boron nitride, since boron nitride has high thermal conductivity, the thermal conductivity of fluororesin filled with boron nitride is increased, and the heat conduction range of arc heat. However, there is a problem that the wear of the fluorine-based resin increases.

  In addition, in the polymer insulator containing the conventional inorganic pigment described above, the inorganic pigment absorbs not only ultraviolet light but also visible light which is originally not required to be shielded. There was a problem that wear increased.

  Thus, it has been difficult for conventional insulators used in circuit breakers and the like to reduce the amount of wear after breaking while preventing deterioration in insulation performance and arc resistance performance.

  Accordingly, the present invention has been made to solve the above-described problems, and is capable of preventing internal deterioration due to an arc and can prevent wear, and the arc-resistant insulator. It aims at providing the circuit breaker provided with the nozzle which consists of.

  In order to achieve the above object, according to one aspect of the present invention, there is provided an arc-resistant insulator disposed in the vicinity of an arc generated between electrodes, wherein the fluorine-based resin is bonded to a predetermined fluorine-based resin. 0.1 to 1% of the weight of the fluororesin containing an inorganic ultraviolet shielding material coated with a white inorganic material having heat resistance not discolored by firing of the resin and having heat resistance not discolored by firing of the fluororesin An arc-resistant insulating material is provided.

  According to another aspect of the present invention, a fixed electrode, a movable electrode that is in contact with and away from the fixed electrode, and a nozzle made of an insulator provided between the electrodes are provided, and is generated between the electrodes when current is interrupted. There is provided a circuit breaker which is extinguished by blowing gas from the nozzle to an arc, wherein the insulator is the arc-resistant insulator described above.

  According to the circuit breaker including the arc-resistant insulator and the nozzle made of the arc-resistant insulator according to the present invention, it is possible to prevent internal deterioration due to the arc and to prevent wear.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram schematically showing a cross section of an arc resistant insulator 10 according to an embodiment of the present invention.

  As shown in FIG. 1, an arc resistant insulator 10 according to an embodiment of the present invention is an inorganic ultraviolet shielding material having heat resistance and chemical resistance that is not discolored by baking a fluorine resin on a fluorine resin 20. 30.

  As the fluorine resin 20, it is particularly preferable to use polytetrafluoroethylene resin or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. The melting point of polytetrafluoroethylene resin is about 327 ° C., and the melting point of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer is about 302 to 310 ° C., which is one of the highest heat resistance among fluororesins. It is because it has.

  In addition, since polytetrafluoroethylene resin has a high viscosity at the time of melting, it is characterized in that the original shape can be maintained even when melted at a high temperature. By taking advantage of such characteristics, the arc-resistant insulator 10 of the present embodiment is arranged with an appropriate distance from the arc, so that even if it is heated by the arc, it is not deformed by heat. Can be prevented.

  Furthermore, since polytetrafluoroethylene resin and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer are gasified into unit structure molecules constituting a polymer during thermal decomposition, no carbides remain, and conductive materials There is an advantage that a decrease in insulation performance due to the generation of is difficult to occur. Furthermore, a cooling effect is exhibited by consuming a large amount of energy when decomposing and gasifying, and the effect of protecting the polytetrafluoroethylene resin itself and the tetrafluoroethylene-perfluoroalkylvinyl ether copolymer itself is also obtained. It is done.

  As described above, the inorganic ultraviolet shielding material 30 has heat resistance and chemical resistance that do not change color when the fluororesin 20 is baked. Further, as shown in FIG. 1, the inorganic ultraviolet shielding material 30 absorbs light in a wavelength region mainly related to internal degradation among the light 41 generated from the arc 40, so that carbides inside the resin are absorbed. The formation can be suppressed, the phenomenon that the fluororesin 20 is blown off by the gas generated inside, and the deterioration of the insulation performance can be suppressed.

  That is, when a conductive material such as carbon is contained, even if the content is small, the insulation resistance of the fluorine-based resin 20 is reduced, and the adjacent arc contains a fluorine-based material containing the conductive material. It became easy to flow on the surface of the resin 20, and the arc resistance was lowered. On the other hand, when the inorganic ultraviolet shielding material 30 used in the present embodiment is contained, the insulation resistance of the fluorine-based resin 20 does not decrease, and as a result, an insulating material having high arc resistance can be obtained. .

  In addition, as the inorganic ultraviolet shielding material 30 used in the present embodiment, the fluorine-based resin 20 has heat resistance that does not change or change color at a temperature around 300 ° C. that is the baking temperature of the fluorine-based resin 20, and before baking. It is preferable to use one having chemical resistance that is not affected by the fluorine-based gas generated from the gas. If an inorganic ultraviolet shielding material that does not have heat resistance or chemical resistance is used, discoloration occurs when the fluororesin is baked, carbides are generated, etc. This is because it causes a decrease.

  As described above, in order to reduce the wear of the insulator while suppressing the deterioration due to the light 41 from the arc 40, the content of the inorganic ultraviolet shielding material 30 is optimized as described later, and an appropriate wavelength is set. It is effective to select an inorganic ultraviolet shielding material 30 that absorbs light. In other words, if light in the wavelength region related to internal carbonization is mainly absorbed and other light is not absorbed, the deterioration of the insulation performance due to internal carbonization is suppressed, and the fluororesin 20 is worn by light and heat. It is considered that an insulator excellent in arc resistance that can achieve both effects of reducing the resistance can be obtained.

  From these viewpoints, the present inventors have conducted intensive studies, and as a result, by using the white inorganic ultraviolet shielding material 30 singly or in combination, it is possible to suppress deterioration in insulation performance due to internal carbonization, and to reduce light and heat. It has been found that both effects of reducing the wear of the fluorine-based resin 20 due to the above can be obtained.

  Next, a specific configuration of the inorganic ultraviolet shielding material 30 will be described.

The inorganic ultraviolet shielding material 30 is composed of any one of titanium oxide, zinc oxide (ZnO), and cerium oxide (CeO ₂ ). Moreover, the inorganic ultraviolet shielding material 30 comprised in either of these may be used individually, respectively, or may be used in combination. For example, the inorganic ultraviolet shielding material 30 composed of titanium oxide and the inorganic ultraviolet shielding material 30 composed of zinc oxide may be mixed and used at a predetermined ratio.

  These inorganic ultraviolet shielding materials 30 are inorganic materials excellent in heat resistance and chemical resistance, and even if contained in the fluorine-based resin 20, they do not change or discolor due to heating during firing. Titanium oxide has a rutile type, anatase type, and brookite type depending on the crystal state, but in order to suppress damage to the fluorine-based resin 20, a rutile type with low activity and small photocatalytic action is selected. It is preferable to do.

  There is an evaluation parameter called “hiding power” as the ability to cover the base when the inorganic ultraviolet shielding material 30 is contained. This “hiding power” is determined by the light reflected by the surface of the inorganic ultraviolet shielding material 30 and the light absorbed by the inorganic ultraviolet shielding material 30, and the higher the amount of reflected light and absorbed light, the higher the hiding power. Become. The hiding power is also related to the particle diameter of the inorganic ultraviolet shielding material 30. When the particle diameter becomes small, for example, when the particle diameter becomes 1/2 or less of the wavelength of light, light different from general reflection and refraction. It is known that the hiding power is remarkably reduced due to the scattering and diffraction phenomenon (for example, Asakura Shoten, Color Material Engineering Handbook Co., Ltd.). The present invention aims at a configuration that absorbs ultraviolet light and absorbs as little light in the visible region as possible. In order to make it difficult to absorb the shortest wavelength of 400 nm in the visible region, the average particle size of the inorganic ultraviolet shielding material 30 needs to be 200 nm (0.2 μm) or less. Therefore, the inorganic ultraviolet shielding material 30 preferably has an average particle size of 0.2 μm or less. Here, the average particle diameter is a value obtained by an air permeation method.

In addition, the inorganic ultraviolet shielding material 30 may be coated with a white inorganic material having heat resistance and chemical resistance that does not change color when the fluorine resin is baked. When the inorganic ultraviolet shielding material 30 is composed of titanium oxide, examples of the white inorganic material to be coated include silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), and boron nitride (BN). Further, when the inorganic ultraviolet shielding material 30 is composed of zinc oxide or cerium oxide, as the white inorganic material to be coated, silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), boron nitride (BN), Examples thereof include titanium oxide. The coating layer covering the inorganic ultraviolet shielding material 30 is formed by attaching a plurality of white inorganic fine particles to the surface of the inorganic ultraviolet shielding material 30. Therefore, the particle size of the white inorganic material forming the coating layer is preferably smaller than that of the inorganic ultraviolet shielding material 30 and having an average particle size of, for example, 20 nm or less. The surface of the inorganic ultraviolet shielding material 30 can be densely coated by using a white inorganic substance having a range of the average particle diameter. The coating layer has functions such as increasing the whiteness, improving chemical resistance, and preventing the inorganic ultraviolet shielding materials 30 from aggregating with each other. By using, these functions can be fully exhibited.

  Even in the case where this coating layer is provided, the average particle size of the inorganic ultraviolet shielding material 30 (including the coating layer) is preferably 0.2 μm or less for the reason described above.

  Here, a method for forming a coating layer on the surface of the inorganic ultraviolet shielding material 30 will be described.

  A coating layer can be formed using a composite particle manufacturing apparatus, for example. This composite particle manufacturing apparatus is a dry type and enables joining of fine powders. Specifically, first, fine particles made of a white inorganic substance, which is a child particle, are mixed in a predetermined ratio with the inorganic ultraviolet shielding material 30, which is a mother particle. Subsequently, the mixed particles are put into a container for performing a coating layer forming step. In the container for performing the coating layer forming step, mechanical thermal energy mainly composed of impact force is given to the particles while dispersing the particles in the gas phase, and the child particles are immobilized on the surface of the mother particles. And the fixed process powder is collected with a collector. In this way, a coating layer made of white inorganic fine particles is formed on the surface of the inorganic ultraviolet shielding material 30.

  Examples of the composite particle production apparatus described above include a hybridization system (manufactured by Nara Machinery Co., Ltd.), a circulation mechanofusion system (manufactured by Hosokawa Micron Corporation), and the like.

  Next, the content rate of the inorganic ultraviolet shielding material 30 contained in the fluorine resin 20 will be described.

  In the arc resistant insulator 10 of the present embodiment, in order to obtain the effect of suppressing internal carbonization, sufficient light absorption is necessary, and there is a content of the inorganic ultraviolet shielding material 30 corresponding thereto. On the other hand, when a large amount of the inorganic ultraviolet shielding material 30 is filled, heat conduction caused by the arc 40 in the fluorine-based resin 20 increases, and as a result, the amount of wear of the insulator made of the fluorine-based resin 20 increases. Therefore, the amount of the inorganic ultraviolet shielding material 30 to be added is preferably set as small as possible if sufficient light absorption can be obtained.

  Here, FIG. 2 is a diagram showing a typical relationship between the reflectance of light at a wavelength of 300 nm and the content of the inorganic ultraviolet shielding material 30 in the fluororesin 20 containing the inorganic ultraviolet shielding material 30.

  As shown in FIG. 2, the content of the inorganic ultraviolet shielding material 30 is 0.1% by weight or more, and the reflectance at which most of the light is absorbed is 40% or less. On the other hand, when the content of the inorganic ultraviolet shielding material 30 exceeds 1% by weight, the reflectance does not decrease sharply and decreases monotonously. As described above, containing the inorganic ultraviolet shielding material 30 unnecessarily increases heat conduction caused by the arc 40 in the fluororesin 20 and increases the amount of wear of the insulator made of the fluororesin 20. It will be different. Therefore, the content of the inorganic ultraviolet shielding material 30 contained in the fluororesin 20 is preferably in the range of 0.1 wt% to 1 wt%. In this range, the content of the inorganic ultraviolet shielding material 30 contained in the fluororesin 20 is from the viewpoint of the ease of obtaining a stable formulation, the small influence of the filling rate error, and the ease of production. It is preferable to set it to 0.2 weight% or more and 0.6 weight% or less.

  Next, a method for manufacturing the arc resistant insulator 10 will be described.

  To the powder of the fluororesin 20 described above, the inorganic ultraviolet shielding material 30 formed by the above-described method and coated with a white inorganic substance is added in an amount of 0.1 to 1% of the weight of the fluororesin 20, and uniformly. Mix. The uniformly mixed mixture is filled into a predetermined mold and compression-molded to produce a compression-molded body. Here, when producing the nozzle of the circuit breaker, for example, a cylindrical compression-formed body having a size capable of producing the nozzle of the circuit breaker is produced.

  Subsequently, the compression formed body is placed in a furnace, the temperature is gradually increased to about 370 ° C., and the powder of the fluororesin 20 is melted and fired. Then, it cools to room temperature by natural cooling, and the arc resistant insulator 10 which is a molded article is obtained. The entire manufacturing process described above takes about 40 to 50 hours.

  Here, when producing the nozzle of a circuit breaker, the nozzle of a circuit breaker is obtained by machining a cylindrical molded product into the shape of the nozzle.

  As described above, according to the arc-resistant insulator 10 according to the embodiment of the present invention, the inorganic ultraviolet shielding material 30 is contained in the fluorine resin 20 at a predetermined ratio, so that the inorganic ultraviolet shielding material 30 is contained. However, it can absorb light in the ultraviolet region involved in internal degradation. As a result, the formation of carbides inside the resin can be suppressed, the phenomenon that the fluorine-based resin 20 is blown away by the gas generated inside can be prevented, and a decrease in insulation performance can be suppressed. Further, by covering the surface of the inorganic ultraviolet shielding material 30 with a coating layer, it is possible to increase whiteness, improve chemical resistance, and prevent the inorganic ultraviolet shielding material 30 from aggregating.

  Moreover, since the inorganic ultraviolet shielding material 30 hardly absorbs light outside the wavelength region that causes internal deterioration, it suppresses decomposition, vaporization, and dissipation of the resin from the surface of the insulator caused by absorbing light and heat. be able to. Therefore, it is possible to suppress the decrease (wear) of the insulator as a whole while suppressing internal deterioration.

  Furthermore, since the content of the inorganic ultraviolet shielding material 30 in the arc resistant insulator 10 is very small, the thermal conductivity of the fluororesin does not increase. Therefore, it is possible to suppress an increase in the amount of wear of the fluororesin caused by the expansion of the heat conduction region. In addition, since the content of the inorganic ultraviolet shielding material 30 in the arc-resistant insulator 10 is very small, it is possible to maintain a mechanical strength substantially the same as that of the fluororesin 20.

  Next, it will be described that the arc-resistant insulator 10 according to the present invention has an excellent effect of preventing internal deterioration due to an arc.

(Evaluation of arc resistance, mechanical strength and volume resistivity)
In order to evaluate arc resistance, mechanical strength, and volume resistivity, Samples 1 to 7 were prepared as shown below.

(Sample 1)
To a polytetrafluoroethylene resin powder having an average particle diameter of 25 μm, 0.6% of the weight of the resin was added to a rutile type titanium oxide having an average particle diameter of 0.01 μm and mixed uniformly. Here, the average particle diameter is a value obtained by an air permeation method.

  Subsequently, the uniformly mixed mixture was filled in a mold having an inner diameter of 100 mm and an inner wall height of 100 mm, and compression-molded at a temperature of 25 ° C. (room temperature) and a pressure of 50 MPa to produce a compression-molded body.

  Subsequently, the compression molded body was placed in a furnace, the temperature was gradually increased to about 370 ° C., and the powder of the fluororesin 20 was melted and fired. After that, it is cooled to room temperature by natural cooling, and by machining, the diameter is 100 mm, the thickness is 3 mm (for arc resistance test and volume resistivity measurement), the diameter is 100 mm, and the thickness is 1 mm (tensile strength test). A cylindrical sample 1 was obtained.

(Sample 2)
To a powder of polytetrafluoroethylene resin having an average particle size of 25 μm, 0.6% of the weight of the resin was added to zinc oxide having an average particle size of 0.02 μm and mixed uniformly.

  The subsequent manufacturing steps were the same as those of the sample 1 described above, and a sample 2 having the same size as the sample 1 was obtained.

(Sample 3)
To a polytetrafluoroethylene resin powder having an average particle diameter of 25 μm, cerium oxide having an average particle diameter of 0.01 μm was added by 0.6% of the weight of the resin and mixed uniformly.

  The subsequent manufacturing steps were the same as in the case of Sample 1 described above, and Sample 3 having the same size as Sample 1 was obtained.

(Sample 4)
A powder of polytetrafluoroethylene resin having an average particle size of 25 μm was coated with zinc oxide having an average particle size of 0.02 μm coated with aluminum oxide having an average particle size of 0.02 μm. % Was added and mixed uniformly.

  The subsequent manufacturing steps were the same as in the case of Sample 1 described above, and Sample 4 having the same size as Sample 1 was obtained.

(Sample 5)
Carbon having an average particle diameter of 0.2 μm was added to a polytetrafluoroethylene resin powder having an average particle diameter of 25 μm in an amount of 0.4% of the weight of the resin, and mixed uniformly.

  The subsequent manufacturing steps were the same as in the case of Sample 1 described above, and Sample 5 having the same size as Sample 1 was obtained.

(Sample 6)
A polytetrafluoroethylene resin powder having an average particle size of 25 μm is filled into a mold having an inner diameter of 100 mm and an inner wall height of 100 mm, and compression-formed at a temperature of 25 ° C. (room temperature) and a pressure of 50 kPa. Was made.

  The subsequent manufacturing steps were the same as those of the sample 1 described above, and a sample 6 having the same size as the sample 1 was obtained.

(Sample 7)
To a polytetrafluoroethylene resin powder having an average particle diameter of 25 μm, boron nitride having an average particle diameter of 10 μm was added at 10% of the weight of the resin and mixed uniformly.

  The subsequent manufacturing steps were the same as in the case of Sample 1 described above, and Sample 7 having the same size as Sample 1 was obtained.

  An arc resistance test, a volume resistivity measurement, and a tensile strength test were performed using the samples 1 to 7 manufactured by the above-described method. Here, the arc resistance test was performed in accordance with Japanese Industrial Standard JIS K6911. Arc resistance refers to the ability of an insulating material to withstand deterioration due to arc, and is the number of seconds measured for the time until conduction and ignition. The volume resistivity was measured according to JIS K6911. The tensile strength test was performed according to JIS K6891. Table 1 shows the test results described above for Sample 1 to Sample 7. Samples 1 to 4 are arc-resistant insulators according to the present invention, and Samples 5 to 7 are comparative examples.

  As shown in Table 1, it was found that the volume resistivity and arc resistance are significantly lowered when carbon as a conductive material is contained as in Sample 5. On the other hand, when a predetermined amount of the inorganic ultraviolet shielding material is contained as in Sample 1 to Sample 4, the volume resistivity is high and the arc resistance is the same as that in Sample 6 widely used as a conventional insulator. It was found that the same level of arc resistance can be maintained.

  Moreover, it turned out that the sample 7 with much content of an additive becomes small in tensile strength. Moreover, although the tensile strength in the samples 1 to 4 is slightly lower than that of the sample 6 that is widely used as a conventional insulator, the tensile strength in the sample 6 is not significantly different and is about the same.

(Evaluation of internal deterioration and weight loss)
In order to evaluate the presence / absence of internal deterioration and the amount of weight loss, Samples 8 to 10 were prepared as shown below.

(Sample 8)
To a polytetrafluoroethylene resin powder having an average particle diameter of 25 μm, 0.5% of the weight of the resin was added to a rutile type titanium oxide having an average particle diameter of 0.01 μm and mixed uniformly.

  The subsequent manufacturing steps were the same as those of the sample 1 described above, and the sample 8 having a diameter of 200 mm and a height of 250 mm was obtained by changing the mold.

(Sample 9)
Zinc oxide having an average particle size of 0.02 μm was added to a polytetrafluoroethylene resin powder having an average particle size of 25 μm in an amount of 0.5% of the weight of the resin and mixed uniformly.

  Subsequent manufacturing steps were the same as in the case of Sample 1 described above, and the sample was changed to obtain Sample 9 having a diameter of 200 mm and a height of 250 mm.

(Sample 10)
To a polytetrafluoroethylene resin powder having an average particle diameter of 25 μm, 0.5% of the weight of the resin was added with cerium oxide having an average particle diameter of 0.01 μm and mixed uniformly.

  Subsequent manufacturing steps were the same as in the case of Sample 1 described above, and the sample 10 having a diameter of 200 mm and a height of 250 mm was obtained by changing the mold.

  Samples 8 to 10 are arc-resistant insulators according to the present invention. For comparison, the samples 6 to 7 have a diameter of 200 mm and a height of 250 mm instead of the mold. Samples were prepared and evaluated for internal deterioration and weight wear.

  Presence or absence of internal deterioration, machine each sample, make nozzles for the same shape of the gas circuit breaker, attach these nozzles to the circuit breaker, observe the cross section of the nozzle after performing the interruption test under the same conditions, The presence or absence of deterioration was observed. Specifically, the cross section of the sample was observed to check for the presence of internal carbonization traces.

  The weight wear amount was evaluated by measuring the weight of the nozzle used in the internal deterioration test before and after the test, and determining the difference between the weights. In this evaluation, in order to compare more accurately, the weight change per unit energy obtained by dividing the weight difference before and after the test by the amount of energy injected in the interruption test was used.

  Table 2 shows the test results described above for Sample 6 to Sample 10. In Table 2, “Yes” indicates that there is internal degradation, and “No” indicates no internal degradation. Here, the case where there is no internal deterioration is a case where there is no internal carbonization trace and there is no erosion associated with internal carbonization. The weight wear amount is shown as a relative value when the weight wear amount per unit energy in the sample 6 is 100. For example, when the weight wear amount per unit energy in the sample 6 is exceeded, the relative value exceeds 100, and when the weight wear amount per unit energy in the sample 6 is less than 100, the relative value is less than 100.

  As shown in Table 2, Sample 8 to Sample 10 had no internal carbonization trace, no erosion due to internal carbonization, and no internal deterioration was confirmed. Moreover, the weight wear amount in the samples 8 to 10 was not different from the weight wear amount in the sample 6 widely used as a conventional insulator, and was similar. On the other hand, in the sample 6 having no inorganic ultraviolet shielding material, many internal deteriorations were observed. In addition, Sample 7 having a large content of additives had a large weight wear amount.

  From the above results, Samples 8 to 10 which are arc-resistant insulators according to the present invention contain an appropriate amount of an ultraviolet shielding agent suitable for a fluorine-based resin, thereby suppressing internal carbonization caused by arc light. It is considered that weight loss of the insulator is suppressed by not absorbing excess light and heat from the arc.

The figure which showed typically the cross section of the arc-resistant insulator of one embodiment which concerns on this invention. The figure which showed the typical relationship of the reflectance of the light in wavelength 300nm, and the content rate of an inorganic ultraviolet shielding material in the fluororesin containing the inorganic ultraviolet shielding material.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Arc-resistant insulation, 20 ... Fluorine-based resin, 30 ... Inorganic ultraviolet shielding material, 40 ... Arc, 41 ... Light.

Claims (8)

An arc-resistant insulator disposed in the vicinity of an arc generated between the electrodes,
A predetermined fluorine-based resin coated with a white inorganic material having heat resistance not discolored by baking of the fluorine-based resin, and an inorganic ultraviolet shielding material having heat resistance not discolored by baking of the fluorine-based resin, the fluorine-based resin An arc-resistant insulating material comprising 0.1 to 1% of the weight of   2. The arc-resistant insulation according to claim 1, wherein the fluororesin is a polytetrafluoroethylene resin or a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.   The arc-resistant insulation according to claim 1 or 2, wherein the inorganic ultraviolet shielding material is composed of any one of titanium oxide, zinc oxide, and cerium oxide, and each is used alone or in combination. .   The arc-resistant insulator according to claim 3, wherein the crystal structure of the titanium oxide is a rutile type.   4. The arc-resistant insulator according to claim 3, wherein when the machine ultraviolet shielding agent is composed of titanium oxide, the white inorganic substance is any one of silicon dioxide, aluminum oxide, and boron nitride. .   The white inorganic substance is any one of silicon dioxide, aluminum oxide, boron nitride, and titanium oxide when the machine ultraviolet shielding agent is composed of zinc oxide or cerium oxide. Arc resistant insulation.   The arc-resistant insulation according to any one of claims 1 to 6, wherein the inorganic ultraviolet shielding material has an average particle diameter of 0.2 µm or less. A fixed electrode, a movable electrode that contacts and separates from the fixed electrode, and a nozzle made of an insulating material provided between the electrodes, and is extinguished by blowing gas from the nozzle to an arc generated between the electrodes when current is interrupted A circuit breaker that
The circuit breaker according to any one of claims 1 to 7, wherein the insulator is an arc-resistant insulator.

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