JP2010160901A - Insulated coating method, insulator, and voltage apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulated coating method and an insulator which can contribute to global environment conservation in insulating treatment of a conductive member of voltage apparatus and have sufficient durability (for example, strength and degradation resistance) and electric characteristics after performing a heat-cycle. <P>SOLUTION: A high-polymer composition obtained by adding and kneading silica powder to a high-polymer material which is a living thing-originated material (biodegradable resin) as a base material is attained. The high-polymer composition is made to a biopolymer compound, and a living thing-originated insulating member is coated to an insulated section of the conductive member by powder-coating insulating powder obtained by making the biopolymer compound into fine particles to the conductive member of voltage apparatus. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for forming an insulating coating layer, an insulator formed by the coating method, and an insulated voltage device.

  For example, in voltage equipment (heavy electrical equipment such as high-voltage equipment) equipped with switchgear such as circuit breakers and disconnectors in the housing, capacity and size have been reduced with the advancement and concentration of society. There is also a strong demand for improvements in safety, reliability (for example, mechanical properties (dielectric breakdown field characteristics, etc.), electrical properties). For example, some of the conductive members of the voltage device are appropriately subjected to insulation treatment (covering the conductive portion (molding) with an insulating material) from the viewpoint of miniaturization and safety of the voltage device. As this insulation treatment, a desired portion (hereinafter referred to as an insulated portion) is formed into a desired shape such as a heat-shrinkable tube made of an insulating polymer material (tube shape, sheet shape, etc.). Apply a method of coating with an insulator), or apply a method of powder-coating a powder (hereinafter referred to as insulating powder) finely divided to such an extent that a coating can be formed on a portion to be insulated. It is known.

  As the insulating member, for example, a material made of a polymer material based on a petroleum-derived substance (starting material) such as a thermoplastic resin (polyethylene, etc.) or a thermosetting resin (epoxy resin, etc.) according to the purpose of use (hereinafter referred to as “insulating member”) The oil-derived insulating member has been generally used. However, when the oil-derived insulating member is disposed, various problems may be caused from the viewpoint of global environmental conservation.

  For example, if a method of incinerating petroleum-derived insulating members is applied, there is a concern that various harmful substances and carbon dioxide may be discharged in large quantities, which may cause problems such as environmental pollution and global warming.

  On the other hand, although a method of simply landfilling petroleum-derived insulating members can be applied, the final disposal site related to the landfill treatment tends to decrease year by year. In addition, there are attempts to collect and reuse (recycle) petroleum-derived insulating members, but they are not well established because they require significant collection costs and energy (energy in the combustion process for reuse). Almost never done.

  Exceptionally, only petroleum-derived insulating members (polyethylene cables used in voltage equipment) with relatively uniform quality are recovered and used as thermal energy. However, since this thermal energy requires a combustion treatment process, As such, there is a risk of causing problems such as environmental pollution and global warming.

  In recent years, an insulating member made of a polymer material based on a biological material (such as a biodegradable resin) (hereinafter referred to as a biological insulating member) has begun to attract attention (for example, Patent Documents 1 and 2). ), Because it has biodegradability (for example, physical properties that are easy to melt at a relatively low temperature), durability (for example, life of strength, deterioration resistance, etc.) is low compared to petroleum-derived insulating members, In particular, it is unsuitable for products such as voltage devices that need to maintain sufficient electrical characteristics (for example, sufficient insulation) for a long period of time, and is not actually applied as an industrial material.

  For example, even a biologically-derived insulating member that has been solidified into a desired shape (solidified into a sheet shape, a pellet shape, etc.) may be deformed when mounted on an insulated treatment site, It is easily damaged by friction. In addition, when the powder coating method is applied, there is a possibility that the thickness of the biological insulating member becomes insufficient or non-uniform.

  For this reason, the said biological-derived insulating member has been limited to application to simple products that do not require durability, electrical characteristics, etc. (for example, household goods that are difficult to collect such as so-called one-way containers).

  To solve these problems, bio-based polymers (derived from non-fossil raw materials) such as PLA (polylactic acid) and PBS (polybutylene succinate) are used to improve the breakdown voltage of biological materials (such as biodegradable resins). A method of adding a hydrolysis control agent and an organic oxide to a polymer) is employed. Furthermore, it has become possible to ensure a long-term life under high temperature and high humidity by performing water vapor permeation control by heat treatment with a crosslinking agent (peroxide) or heat shrink tube treatment (for example, Patent Document 3).

JP 2002-53699 A JP 2002-358829 A JP 2008-257976 A

  When a bio-based polymer is used, thermal stress fracture may occur on the low temperature side rarely due to a difference in linear expansion coefficient between the conductor to be coated and the insulator to be coated. In insulating treatment of conductive members of voltage equipment, it is required to contribute to global environmental conservation and to be able to impart sufficient durability (for example, strength, deterioration resistance, etc.) and electrical characteristics.

  The present invention has been made on the basis of the above problems, and in the insulation treatment of conductive members of voltage equipment, is totally different from the technology applied to daily necessities as described above, and can contribute to global environmental conservation. Another object of the present invention is to provide an insulating coating method that can provide sufficient durability and electrical characteristics.

  Specifically, the insulating coating method according to claim 1 is a method in which a polymer composition containing a polymer material based on a biological material and silica powder is coated on a portion to be insulated by a powder coating method. It is characterized by doing.

  The insulating coating method according to claim 2 is characterized in that, in the insulating coating method according to claim 1, the weight of the silica powder added to 100 weights of the base material is 30 to 110 weights. To do.

The insulating coating method according to claim 3 is characterized in that, in the insulating coating method according to claim 1, the weight of the silica powder added to 100 weights of the base material is 40 to 100 weights. To do.

  The insulating coating method according to claim 4 is the insulating coating method according to any one of claims 1 to 3, wherein an average particle diameter of the silica powder is 5 μm or more and 20 μm or less. .

  The insulating coating method according to claim 5 is the insulating coating method according to any one of claims 1 to 4, wherein the base material is acetylated cellulose, polylactic acid, polybutylene succinate, polytrimethylene. It is characterized by comprising at least one bio-based polymer among terephthalate, esterified starch, starch-based polymer, and chitosan-based polymer.

  The insulating coating method according to claim 6 is the insulating coating method according to any one of claims 1 to 5, wherein the polymer composition has a -N = C = N- structure in a molecule. The hydrolysis inhibitor which has is added, It is characterized by the above-mentioned.

  The insulating coating method according to claim 7 is the insulating coating method according to any one of claims 1 to 6, wherein the polymer composition has a cross-link having an —O—O— structure in a molecule. An agent is added.

  The insulator according to claim 8 is characterized in that a polymer composition containing a polymer material based on a biological substance and silica powder is coated on a portion to be insulated by a powder coating method. To do.

  The voltage device according to claim 9, wherein a polymer composition including a polymer material based on a biological material and silica powder is insulated by a powder coating method with respect to a site to be insulated. And

  As described above, according to the insulating coating method of the present invention, it is possible to obtain an insulator that can contribute to global environmental conservation and has sufficient durability (for example, life such as strength and deterioration resistance) and electrical characteristics. .

  Hereinafter, the insulating coating method in the embodiment of the present invention will be described.

  The insulation coating method according to the present invention relates to all polymer-based insulation constituent materials, and is particularly applicable to insulation of a power system having a high voltage and a high temperature.

  A non-fossil raw material polymer material (biological material) is used as an alternative to the current insulating material. By mixing silica powder with a biological material and forming an insulating layer on the conductive member (insulated part) by the powder coating method, the difference in linear expansion coefficient between the conductive member and the insulating layer is reduced. Maintain good insulation properties.

<Biological insulating material>
In the biological insulating member of the present embodiment, a polymer composition obtained by adding a hydrolysis inhibitor, a crosslinking agent or the like to a polymer material based on a biological material (such as a biodegradable resin) and kneading the polymer material. Add silica powder. The insulating powder obtained by micronizing the polymer composition to which the silica powder is added is coated on the portion to be insulated by the powder coating method.

[Polymer material]
As the polymer material applied to the polymer composition of the biological insulating member, various materials can be applied depending on the type of biological material used as the base material, the generation process, and the like.

  For example, bio-based polymers classified into acetylated cellulose, polylactic acid, polybutylene succinate, polytrimethylene terephthalate, esterified starch, starch-based polymer, chitosan-based polymer, etc. from the viewpoint of insulation, material homogeneity, etc. It is done.

  These biobase polymers can be used singly or in combination as appropriate. Of these, those made of polybutylene succinate are relatively flexible.

  Of the components of the polybutylene succinate, succinic acid and butanediol are generally derived from petroleum, but in recent years, those derived from living organisms have begun to appear. It is clear that the nate can be applied as a bio-based polymer (for example, GS Pla® used in the examples copolymerizes lactic acid with succinic acid and butanediol).

  Since these bio-based polymers are carbon neutral, it is considered that new carbon dioxide is hardly generated even if a product or the like using the bio-based polymer is incinerated.

[Silica powder]
The silica powder added to the polymer composition has an average particle size of 5 to 20 μm. The average particle diameter here is a particle diameter corresponding to 50% of the cumulative distribution on a volume basis, and is measured by a wet particle size distribution measuring apparatus.

[Hydrolysis inhibitor]
As a hydrolysis inhibitor applied to the polymer composition, a —N═C═N— structure (R ₁ —N═C═N—R ₂ structure (R ₁ and R ₂ are alkyl groups) in the molecule) For example, a carbodiimide compound may be used. The compound having an effect of inhibiting hydrolysis by a supplemental reaction with active hydrogen (carboxylic acid generated by hydrolysis, active hydrogen of a hydroxyl group). Although the physical properties and reaction rate of the hydrolysis inhibitor itself vary depending on the types of R ₁ and R ₂ , the essential functions (such as supplemental reaction with active hydrogen) are substantially the same.

[Crosslinking agent]
As a crosslinking agent applied to the polymer composition, one having an —O—O— structure in the molecule and causing a crosslinking reaction at a predetermined temperature is used, and examples thereof include peroxide. This peroxide has the property of radically decomposing the —O—O— structure site under the influence of heat, and can be applied as a cross-linking agent. Various peroxides having different half-life temperatures (for example, Japanese fats and oils) Perhexa V (10-hour half-life temperature 105 ° C), Permill D (10-hour half-life temperature 116 ° C), Perhexa 25B (10-hour half-life temperature 118 ° C), Perbutyl P (10-hour half-life temperature 119 ° C) Perbutyl C (10-hour half-life temperature 120 ° C), Perhexyl D (10-hour half-life temperature 116 ° C), Perbutyl D (10-hour half-life temperature 124 ° C), Perhexine 25B (10-hour half-life temperature 128 ° C)) Are known.

  When the peroxide is kneaded with a polymer material, etc., the temperature rise of the kneaded material depends on the kneading machine, the blending amount of the polymer material in the kneaded material, kneading conditions, the presence or absence of a cooling mechanism, etc. Different. For example, the polymer material is maintained in an atmosphere at a temperature higher than the melting temperature of the polymer material, and the polymer material may self-heat (shear heat is generated). May cause a reaction.

  For this reason, it is preferable to appropriately select (for example, select a peroxide having a half-life temperature in the vicinity of the melting temperature) as to the kind and amount of the peroxide. For example, when the melting temperature of the polymer material is about 110 ° C. and the shear heat is about 20 ° C., for example, perbutyl D, perhexine 25B, or the like is used. In addition, in peroxide, there are products that are handled as dangerous goods from the viewpoint of the Fire Service Law, but there are also non-dangerous goods grade products that contain, for example, inert fillers, etc. It is preferable.

[Insulating powder]
As the insulating powder obtained by pulverizing the silica powder-containing polymer composition, a biologically-derived insulating member is applied to a target conductive member (insulated treatment site) by a powder coating method using the insulating powder. Apply micronized material to the extent that it can be formed. For example, the average particle size is about 30 μm to 300 μm, preferably about 50 μm to 250 μm.

  In addition, for example, those having a relatively large average particle diameter (for example, those having a particle size of 500 μm or more) are excluded or re-micronized (to the extent that a biologically-derived insulating member can be formed on an insulating treatment site by a powder coating method) It may be applied after pulverization.

  In addition, although the particle size and powder shape of the insulating powder obtained by pulverization vary depending on the type (model, model, etc.) of the device used for pulverization, the pulverization time, etc., as described above. Any range may be used as long as the target biological insulating member can be formed by the powder coating method.

  Various milling apparatuses can be applied to the apparatus used for the above-mentioned fine pulverization, and examples include apparatuses using rotation, impact, vibration and the like. It should be noted that there is a considerable amount of heat generated during the pulverization by the mill apparatus, and the target insulating powder itself may be unintentionally melted (self-bonding) or deteriorated due to the heat. In such a case, it is preferable to cool the entire mill device or a part (part relating to pulverization), and the polymer composition itself before pulverization is cooled in advance (refrigerator, freezer, liquid nitrogen, etc.). Cooling). In addition, when the polymer composition cannot be charged into the mill apparatus due to a large lump state of the polymer composition, the polymer composition may be coarsely pulverized to such an extent that the polymer composition can be charged.

[Coating method]
Examples of the powder coating method include a fluid dipping method and an electrostatic coating method. Although the fluid immersion method and the electrostatic coating method are different in each process, the purpose (coating) and the result (the degree of coating) are the same.

  In the case of the fluidized immersion method, the surface of the insulation target portion of the target conductive member is preheated (preheated), and the conductive member (at least in the fluidized immersion bath filled with insulating powder) In other words, the insulating powder is soaked by the above preheating to melt the insulating powder, and the melt is attached to the insulated portion to form a biological insulating member. In the fluidized immersion bath, holes having a shape equivalent to or smaller than the size of the insulating powder (B stage in the case of thermosetting resin) or less than the size of the insulating powder are side walls (bottom wall, etc.). And a porous type structure having a plurality of perforations, for example, those obtained by sintering, fiber cloth, or machining.

  By equally injecting an inert gas such as air, dry air, nitrogen, dry nitrogen, etc. (injected under atmospheric pressure) into the fluid immersion tank from each hole formed in the side wall as described above, The insulating powder in the fluid immersion bath can be fluidized.

  Then, the insulating part that has been heated as described above is brought into contact with the insulating powder that flows as described above (soaked in a fluidized immersion bath) to thereby insulate the part to be insulated. A melt of conductive powder adheres and is coated.

The flow rate of the inert gas is appropriately set according to the particle size, distribution, shape, density, etc. of the target insulating powder. For example, based on the linear velocity (cm / min) of the value obtained by dividing the gas flow rate (cm ³ / min) by the effective area (effective area (cm ² ) of the region where the inert gas is uniformly ejected in the fluidized immersion bath). Can be set. For example, it is set to about 0.5 cm / min to 50 cm / min (more preferably 1 cm / min to 20 cm / min).

[Conductive member (insulated part)]
The conductive member to be coated (insulated part) can be any of various materials (copper, iron, aluminum, etc.) and shapes (columnar, (A prismatic shape, a linear shape, a flat plate shape, a knitted wire shape, etc.) can be applied, and examples thereof include a copper bus bar.

  For example, there is no major problem even if an edge portion is present in the part to be insulated, but when the edge portion is chamfered (C surface processing, R surface processing), the edge coverage is improved and the insulating powder is improved. The thickness of the biological insulating member due to the melt of the body is sufficient, and the risk of cracking of the biological insulating member due to stress can be reduced, which is preferable.

  For example, when a conductive member (for example, a bus bar) is formed by pultrusion molding or the like, it is preferable that the edge portion is an R surface. The degree of risk reduction varies depending on the degree of the chamfering process, but there is no major problem even if the edge portion exists as described above. What is necessary is just to carry out suitably.

  Of the conductive members, for example, portions that require electrical conductivity (for example, locations that can be electrically connected) and locations related to work holding, positioning, etc. (positioning holes, etc.) do not require insulation treatment, so It is preferable to perform masking.

  The preheating temperature of the surface to be insulated is set to a temperature range in which the melt of the insulating powder adheres and is coated when the portion to be insulated is immersed in the fluidized immersion bath, and the processing temperature of the insulating powder ( (Softening temperature, melting point, glass transition temperature, etc.), heat capacity (specific heat, specific gravity, heat capacity due to shape, etc.) of the part to be insulated itself, heat dissipation (cooling) characteristics, and thickness of the target biologically-derived insulating member It can be set.

  When the preheating temperature is too low, the insulating powder (melt) becomes difficult to adhere to the part to be insulated, and when the preheating temperature is too high, discoloration, foaming, expansion, etc. occur in the coated biological insulating member. In order to generate easily, it is set as the range from the temperature 20 degreeC lower than the processing temperature of insulating powder to the temperature which this insulating powder decomposes | disassembles, for example. Preferably, the range is from the processing temperature of the insulating powder to a temperature 100 ° C. higher than the processing temperature. A specific example of the case where the insulating powder of the present embodiment is applied includes a temperature range of about 110 ° C. to 240 ° C.

  The soaking time and soaking position (spatial position and direction during soaking) of the part to be insulated with respect to the fluidized immersion tank depends on the thickness of the biologically-derived insulating member by the melt, the preheating temperature of the part to be insulated, the shape, etc. The immersion may be repeated a plurality of times.

  In addition, during the period from the start of immersion of the part to be insulated to the constant immersion time, the biological insulating member thickness increases with time, but after the predetermined immersion time, the biological insulating member thickness is It tends to be constant or non-uniform (surface condition is rough).

  For example, depending on the shape of the part to be insulated, the melt may be difficult to fix (for example, when peeled) or may hang down due to gravity, and the thickness tends to be non-uniform. Such a tendency seems to occur even if the preheating temperature is too low or too high, and it is preferable to appropriately adjust the immersion time, the number of immersions, the immersion position, the preheating temperature of the part to be insulated, and the like.

  Further, the biological insulating member coated as described above may be cross-linked by performing a heat treatment or the like. For example, the cross-linking may be performed by heat treatment that can be performed after coating as described above (for example, heat treatment for the purpose of reducing the thickness variation of the coating, surface roughness, internal stress, etc.).

<Others>
In the bio-derived insulating member and petroleum-derived insulating member of the present embodiment, in addition to the polymer material, various additives generally used in the field of polymer material molding technology, such as a heat stabilizer, a light stabilizer, etc. Aiming at agents (ultraviolet ray inhibitors), antioxidants, anti-aging agents, pigments, colorants, inorganic fillers (fillers), fine inorganic fillers (nanoparticles), flame retardants, antibacterial agents, anticorrosives, etc. Insulating powder for voltage equipment, insulation processing method, and voltage equipment may be used as appropriate as long as the characteristics of the voltage equipment are not impaired.

  For example, in the case of biologically derived insulating members, cross-linking by addition of peroxide for the purpose of stabilizing the coating by the melt in the powder coating method, addition of a coupling agent for the purpose of stabilizing the functional group, etc. You can go.

  Next, an example of an insulated voltage device in the present embodiment will be described. In each of the following examples, both ends of a rectangular flat plate (length: 1200 mm, width: 40 mm, thickness: 5 mm) are masked on both ends (100 mm in the longitudinal direction from each end), and the copper bus bar The center part (other than the masking region) is coated with a biological insulating member by using an insulating powder under various conditions by a fluid immersion method, and further covering the biological insulating member with a petroleum-derived insulating member. Thus, various samples were obtained, and the electrical characteristics and durability of each sample were examined.

[Example]
As a biologically-derived insulating member, first, a pellet of polybutylene succinate (GS Pla (registered trademark) AZ-61T (MI = 30) manufactured by Mitsubishi Chemical Corporation) and liquid peroxide (Perbutyl D manufactured by NOF Corporation) 2 phr was sprinkled and premixed together with 4 phr of powdered carbodiimide (Carbodilite LA-1 manufactured by Nisshinbo Industries, Inc.).

  Furthermore, silica powder (manufactured by Tatsumori Co., Ltd., MCF-4 (average particle size 12 μm)) was added during the preliminary mixing. The amount of silica powder added was 10 phr to 120 phr, and samples were prepared every 10 phr.

  A sample to which no silica powder was added was referred to as Comparative Example 1, and samples to which 10 phr, 20 phr, and 120 phr of silica powder were added were referred to as Comparative Example 2, Comparative Example 3, and Comparative Example 4, respectively. And the sample which added 30 phr-110 phr of silica powder was made into Example 1- Example 9, respectively.

  Next, the mixture is put into a twin-screw kneader-extruder (ZE40A manufactured by Belstolf) and kneaded. A pellet-shaped polymer composition was obtained by cutting into a shape of about several millimeters.

  Then, while cooling the spiral mill (manufactured by Seishin Enterprise Co., Ltd.) (cooling the whole mill apparatus or a part thereof), the mill was cooled with the above-described polymer composition (if necessary, with a refrigerator or liquid nitrogen, etc.) (Polymer composition) was added and pulverized to obtain an insulating powder having an average particle size of 30 to 300 μm.

  Thereafter, the insulating powder is put into a fluidized immersion tank (manufactured by Nakata Coating Co., Ltd.), and an inert gas (nitrogen gas) is ejected into the immersion tank (a flow rate of 0.5 to 50 cm / min). The insulating powder is made to flow, and the masked copper bus bar surface is preheated at 180 ° C., and then is once in the insulating powder (each immersion time is 10 seconds). A sample coated with a biological insulating member (thickness: 1.4 mm) was obtained by adhering a melt of

  First, in each of the samples (Comparative Examples 1 to 4 and Examples 1 to 9), an initial breakdown voltage value (BDV value) when an alternating voltage is applied (applied to both ends where the melt was not coated by masking). ), The electrical characteristics were examined by measuring the initial breakdown electric field value.

  Next, assuming the temperature change assumed in the actual environment of the voltage device (change from the high temperature region that can be applied to the bus bar to the low sound region that can be applied when the device is stopped in winter in Hokkaido), each sample is subjected to a high temperature atmosphere. Heat cycle test with 30 cycles of work (1 cycle; 100 ° C, 8 hours, -40 ° C, 8 hours, transient time 4 hours each) left in a low temperature (100 ° C) and low temperature atmosphere (-40 ° C) Then, each dielectric breakdown voltage value (hereinafter referred to as a post-heat cycle breakdown voltage value) was measured.

  Table 1 shows the results of the initial breakdown voltage value, the initial breakdown electric field value measurement, and the breakdown voltage measurement value after the heat cycle.

  From the results shown in Table 1, it can be seen that by adding silica powder to the bio-based polymer that is a non-fossil raw material, it is possible to suppress thermal breakdown due to the difference in the coefficient of linear expansion of the conductor and to maintain the insulation characteristics even after the heat cycle. It was.

  As shown in Table 1, in the sample (Comparative Examples 1 to 3) in which the silica powder was not added or the amount of silica powder added was small, the biological insulating member was in the initial stage before the heat cycle test was completed. Since breakage was observed, it can be read that thermal stress was generated between the bus bar and the biological insulating member by the heat cycle test.

  On the other hand, the samples (Examples 1 to 9) in which the addition amount of silica powder is 30 phr or more and 110 phr or less have sufficient insulating properties even after the heat cycle. In particular, since the breakdown voltage value after the heat cycle of the sample (Examples 2 to 8) in which the addition amount of silica powder is 40 phr or more and 110 phr or less is almost the same as the initial breakdown voltage value, both electrical characteristics and durability are good. Turned out to be.

  In addition, it was confirmed that in the sample in which the amount of silica powder added was 120 phr or more (Comparative Example 4), the insulating powder had a high viscosity and the moldability of the biological insulating member was lost.

  Therefore, the addition amount of silica powder is preferably 30 phr or more and 110 phr or less, and the addition amount of silica powder is particularly preferably 40 phr or more and 100 phr or less.

  In the formation of the biologically-derived insulating member, when the preheating temperature was set to 100 ° C. to 280 ° C., when the preheating temperature was 100 ° C. or less, the insulation powder was not covered with the melt and the preheating was not observed. When the temperature was 260 ° C. or higher, it was confirmed that discoloration, foaming, expansion, and the like were likely to occur in the biological insulating member. Moreover, if this preheating temperature is about 110 degreeC-240 degreeC, it could confirm that a biological origin insulation member could fully be formed and the said discoloration, foaming, expansion | swelling, etc. would not arise.

  Therefore, as in the embodiment, when the biologically-derived insulating member to which silica powder is added is coated on the portion to be insulated, in the insulation treatment of the conductive member of the voltage device, it contributes to global environmental conservation and has sufficient durability ( For example, strength, deterioration resistance, etc.) and electrical characteristics can be imparted, and it has been confirmed that the present invention is sufficiently applicable to voltage devices such as actual heavy electrical devices.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

Claims (9)

An insulating coating method, wherein a polymer composition containing a polymer material based on a biological material and silica powder is coated on a portion to be insulated by a powder coating method. The weight of the silica powder added to 100 weight of the substrate is
The insulation coating method according to claim 1, wherein the insulation coating method is 30 to 110 weight. The weight of the silica powder added to 100 weight of the substrate is
The insulation coating method according to claim 1, wherein the insulation coating method is 40 to 100 weights. The average particle size of the silica powder is
The insulating coating method according to claim 1, wherein the insulating coating method is 5 μm or more and 20 μm or less. The substrate is composed of at least one bio-based polymer of acetylated cellulose, polylactic acid, polybutylene succinate, polytrimethylene terephthalate, esterified starch, starch-based polymer, and chitosan-based polymer. The insulating coating method according to any one of claims 1 to 4. The polymer composition includes
6. The insulating coating method according to claim 1, wherein a hydrolysis inhibitor having a —N═C═N— structure is added in the molecule. The polymer composition includes
The insulating coating method according to any one of claims 1 to 6, wherein a crosslinking agent having an -O-O- structure in the molecule is added. An insulator, wherein a polymer composition containing a polymer material based on a biological substance and silica powder is coated on a portion to be insulated by a powder coating method. A voltage device, wherein a polymer composition including a polymer material based on a biological material and silica powder is insulated by a powder coating method on a portion to be insulated.