JPS6334611B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric iron core having a highly heat-resistant insulating coating that improves the electrical insulation properties of various electrical devices at high temperatures, and a method for manufacturing the same.

In recent years, there has been a trend toward smaller and lighter rotating electrical equipment and other electrical equipment, and as rotating electrical equipment is subject to increasingly high loads and tends to generate high heat, an insulation treatment method that can maintain insulation even at high temperatures has been developed. development is strongly desired.

Conventionally, as heat-resistant insulation treatment for rotating electric equipment, etc., coil windings are heat-resistant insulated with silicone resin or a mixture of silicone resin and high-melting point powder, as described in Japanese Patent Application Laid-Open No. 167305/1984. There are known ways to treat it.

However, the coil winding treated with heat-resistant insulation using this method has a 300%
A strong insulating layer exists between the coils in the temperature range below ~350℃ and in the temperature range above 600℃ where high melting point inorganic powder melts and becomes enamelled, but at 350℃ in the middle
Silicone resin decomposes in the temperature range from 350℃ to 600℃, while high melting point inorganic powder does not melt and has almost no mechanical strength, so the insulating layer easily peels off and falls off from between the coils. When maintained at a temperature range of 200 to 3000, it did not function as an insulating layer and was extremely incomplete.

Furthermore, as a method for heat-resistant insulation treatment of an electric iron core, as shown in FIG. There is a law.

As shown in Figure 2, another method for heat-resistant insulation treatment is to use a bis-A type epoxy resin powder coating combined with a novolac-type epoxy resin that has good heat resistance by fluid dipping, hot spraying, or static coating. There is a powder coating method in which the insulating layer 5 is formed by adhering it to the surface (slot portion) of the electric iron core 1 by a current dynamic dipping method, an electrostatic spray method, or the like, and melting and hardening it by heating.

However, with the above-mentioned insulator method, when applying heat-resistant insulation treatment, the structure becomes complicated and requires extremely advanced molding technology, which increases the cost of the finished product and also reduces the amount of organic matter. Therefore, there is a limit to its heat resistance.

On the other hand, powder coating methods such as fluidized dipping method, hot spray method, electrostatic dynamic dipping method, electrostatic spray method, etc. using bis A type epoxy resin powder coating combined with the above-mentioned novolak type epoxy resin with good heat resistance. However, since the heat resistance of the resin itself is limited, the heat-resistant insulation treatment described above is impossible. For this reason, BisA using a novolac type epoxy resin
It is easily possible to replace the type epoxy resin with a known highly heat resistant resin such as a polyimide resin or a polyphenylene resin.

However, when this replacement is actually carried out, the high melting point of these resins makes it difficult to obtain an insulating layer with a good appearance when powder coating, and the adhesion between the electric iron core element and the insulating layer is poor. When winding a wire on top of an insulating layer, the slip of the winding becomes poor, making high-speed winding impossible, and the insulating layer cracks due to poor adhesion to the element body.
Peeling occurred and the working efficiency during winding was extremely poor, making it difficult to use it practically.

Also, any of the above-mentioned high heat resistant resins have a rating of 500 to 600.
Because it carbonizes at temperatures of 500 to 600 degrees Celsius, it was not possible to maintain an insulating state for a long time at temperatures of 500 to 600 degrees Celsius.

As a way to further increase heat resistance, for example,
As described in Japanese Patent Application No. 56-23275, a first layer made of an inorganic substance having good adhesion to the base material is formed on a base material such as metal, and a layer made of an inorganic substance having good adhesion to the base material is formed on top of the base material such as a metal. A heat-resistant insulation treatment method is also known in which a second layer is formed of a mixture of an inorganic substance with a high melting point and a binder substance.

However, even with this method, when the second layer is kept in the temperature range from the temperature at which the binder material decomposes to the point at which the high melting point inorganic material softens, the second layer has almost no mechanical strength and easily peels off and falls off from the base material. However, as a heat-resistant insulation treatment, it was extremely incomplete.

The present invention overcomes these drawbacks of the prior art and
As a result of studying heat-resistant insulation treatment methods that can maintain good insulation properties even at high temperatures, we found that by coating the electric iron core with a mixture of a specific heat-resistant resin and a specific inorganic material, work efficiency was improved during high-speed winding. We discovered that it was possible to obtain an electric iron core with an insulating coating that had good insulation properties and did not cause any abnormality in insulation effect even at temperatures of 500 to 600°C under high loads, and we conducted further intensive research. It is.

The details of the present invention will be described below.

The present invention uses an epoxy resin with a melting point of 40°C or higher that is modified with an epoxy resin in the range of 10 to 50% by weight using an organic silicone intermediate having a functional group that can react with an epoxy resin containing a hydroxyl group on the surface of an electric iron core. Silicone modified epoxy resin with equivalent weight of 400-2000
(A) and low melting point glass with a melting point of 400℃~500℃
The main component is an inorganic filler (B) containing 10% by weight or more, and is characterized by having a hardened coating layer of a mixture consisting of (A):(B) = 20:80 to 60:40 in weight ratio. The epoxy resin is modified in the range of 10 to 50% by weight with an organic silicone intermediate having a functional group that can react with the electrical iron core and the hydroxyl group-containing epoxy resin, with a melting point of 40°C or higher and an epoxy equivalent of 400.
~2000 silicone modified epoxy resin (A) and 400~
Contains 10% or more of low melting point glass with a melting point of 500℃, the main component is an inorganic filler (B) with an average particle size of 1μ to 60μ, and the weight ratio is (A):(B) = 20:80 ~ 60:40
After adhering a powder composition consisting of 90% by weight or more of particles having a particle size of 10μ to 150μ on the surface of an electric iron core, this is melted and hardened by heating. The present invention relates to a method of manufacturing an electric iron core having a highly heat-resistant insulation coating, which is characterized by forming an insulation coating.

The silicone-modified epoxy resin (A) used in the present invention is obtained by modifying an epoxy resin in a range of 10 to 50% by weight with an organic silicone intermediate having a functional group that can react with an epoxy resin containing a hydroxyl group. 40℃ or higher, epoxy equivalent 400-2000
preferably has a melting point of 40°C to 90°C, more preferably 60°C to 75°C, and a number average molecular weight of 700 to 75°C.
3,000, and those having an epoxy equivalent of 700 to 1,200 are preferably used.

Modification with organosilicone intermediates: 10% by weight
If it is less than 50% by weight, the heat resistance will be insufficient, and if it is more than 50% by weight, the wettability with other inorganic fillers or the iron core element will be insufficient. If the melting point is below 40°C, too much flow will occur, resulting in extremely low edge coverage of the insulating layer, resulting in an extremely high incidence of insulation defects, and if it is made into a powder composition, it will not be possible to leave it at room temperature. However, blocking occurs within a few hours.

On the other hand, if the melting point exceeds 90°C, it becomes difficult to form a flow, so the wettability with the iron core element and the smoothness of the appearance tend to decrease, making it difficult to obtain a coated product with a good appearance. Moreover, when winding is performed on the insulating layer, cracking and peeling of the insulating layer are likely to occur. Furthermore, if the blending ratio of resin is increased in an attempt to improve the appearance, the heat resistance tends to become insufficient. When the epoxy equivalent is less than 400, the crosslinking density of the insulating layer becomes too high, resulting in frequent cracking and peeling of the insulating layer when winding on the insulating layer.On the other hand, when the epoxy equivalent is more than 2000, Since the crosslinking density of the insulating layer becomes too low, when the wire is wound on the insulating layer, the winding wire sinks into the insulating layer, and the incidence of insulation defects increases extremely.

In order to improve flow characteristics or adhesion, it is also possible to use a known epoxy resin, such as a bis-type epoxy resin, a novolak-type epoxy resin, a glycerin triether-type epoxy resin, etc.

Also, in order to improve heat resistance in the temperature range from room temperature to 300-400℃, it is also possible to use high heat-resistant resins such as polyimide, polyamideimide, polyesterimide, polyphenylene oxide, polysulfone, and polybenzimidazole. It is.

The organic silicone intermediate used to obtain the silicone-modified epoxy resin (A) of the present invention includes:
Those that have functional groups that can react with epoxy resins containing hydroxyl groups, that is, those that have hydroxyl groups directly bonded to silicon atoms, halogen groups such as chlorine and bromine, alkoxy groups such as methoxy groups and ethoxy groups, and acetoxy groups. Among these, those having an alkoxy group are most preferred because they can easily react with the epoxy resin.

For other substituents directly bonded to silicon,
For example, those having two or more types of groups having different decomposition temperatures, such as a methyl group and a phenyl group, are preferable because decomposition occurs in stages at high temperatures.

Furthermore, the epoxy resin used to obtain the silicone-modified epoxy resin (A) of the present invention has 2
Examples include bisphenol-type epoxy resins, halogenated bisphenol-type epoxy resins, novolac-type epoxy resins, resorcinol-type epoxy resins, tetrahydroxydiphenylethane-type epoxy resins, polyalcohol-type epoxy resins, Polyglycol type epoxy resin, glycerin triether type epoxy resin,
Polyolefin type epoxy resins, alicyclic type epoxy resins, etc. are not particularly limited, and these epoxy resins can be used alone or in combination.

The inorganic filler (B) used in the present invention has an average particle size of 1 μ to 60 μ and contains 10% by weight or more of a low melting point glass powder having a melting point of 400° C. to 500° C.

The inorganic powder used in combination with the low melting point glass powder is not particularly limited, and examples include silica,
One or more types of inorganic powders such as clay, mica, calcium carbonate, alumina, aluminum hydroxide, and high melting point glass are used, and among these, silica and alumina are most preferably used.

That is, the inorganic filler (B) used in the present invention is a mixture of low melting point glass having a melting point of 400°C to 500°C and inorganic powders such as silica and alumina, and contains 10% by weight of low melting point glass. The most preferable inorganic filler (B) is 20 to 60% by weight of low melting point glass powder, 5 to 60% by weight of alumina powder.
30% by weight and 25 to 75% by weight of silica powder as main components.

Glass frits with a melting point of lower than 400°C are advantageous for film formation at high temperatures, but
Since the composition contains a large amount of lead compounds, it is unfavorable from a sanitary standpoint, and since it softens significantly at 400°C to 500°C, the strength of the insulating layer at high temperatures becomes insufficient. Furthermore, if the glass frit has a melting point higher than 500°C, film formation at high temperatures will be insufficient.

350℃~600℃ where the above low melting point glass softens and melts
To improve the hardness of the insulation layer at 350℃~600℃
It is preferable to use inorganic powders such as silica and alumina that do not soften, melt, or decompose even at ℃, and the main components are 20 to 60% by weight of low melting point glass powder, 5 to 30% by weight of alumina powder, and 25 to 75% by weight of silica powder. Since the hardness of the insulating layer is improved most depending on the mixing ratio, it is preferable to use them together within this range.

The inorganic filler (B) used in the present invention has an average particle size of
1μ to 60μ, preferably 20μ to
40μ is used. If the average particle size is larger than 60μ, a smooth surface cannot be obtained, and if it is smaller than 1μ,
The amount of oil absorbed by the powder increases, making it impossible to obtain sufficient flow.

Silicone modified epoxy resin (A) and low melting point glass powder-containing inorganic filler (B) used in the present invention
As a mixture having as main constituents, the blending ratio of silicone-modified epoxy resin (A) and inorganic filler containing low melting point glass powder (B) is 20:80 to 60:
A range of 40 is used. When the blending ratio of silicone-modified epoxy resin (A) is less than 20% by weight,
Good flow characteristics cannot be obtained, and if the content exceeds 60% by weight, heat resistance becomes insufficient.

As the curing agent for the silicone-modified epoxy resin according to the present invention, curing agents commonly used for epoxy resins can be used as they are. That is, organic compounds, organic mineral acid esters, and organic metal compounds having a carboxylic acid anhydride group, an amino group, a carboxyl group, a carboxylic acid hydrazide group, a hydrosyl group, a -SH group, a CONH group, a -NCO group, and a -NCS group. Conventionally known hardening agents such as Lewis acids, titanium, zinc, boron or aluminum compounds containing organic groups, and other acidic or basic compounds are used. For example, aliphatic polyamines such as ethylenediamine and triethylenetetramine, aliphatic hydroxylamines such as monoethanolamine and propanolamine, metaphenylenediamine,
Aromatic amines such as 4,4'-diaminodiphenylmethane, aliphatic amines with a cyclic structure such as piperazine and triethylenediamine, imidazoles such as 2-ethyl 4-methylimidazole and 2-phenylimidazole, and other nitrogen-containing Examples of the curing agent include cycyandiamide carboxylic acid dihydrazide. Examples of acid curing agents include polyhydric carboxylic acids such as phthalic acid, maleic acid, tetrahydrophthalic acid, trimellitic acid, azelaic acid, benzophenonetetracarboxylic acid, and adipic acid, and their anhydrides.

Other examples include -NCO group-containing prepolymers of polyurethane resins, titanium and zinc compounds containing organic groups such as tetrabutyl titanate and zinc octoate. In addition, some of these curing agents can achieve rapid curing by using a small amount of a curing accelerator such as tertiary amine, imidazole, organic acid metal salt, Lewis acid, or amine complex salt.
It is blended as needed. Among these curing agents, imidazole, dicyandiamide, and carboxylic acid dihydrazide are particularly preferably used for reasons such as storage stability.

Silicone modified epoxy resin (A) and low melting point glass powder-containing inorganic filler (B) used in the present invention
In addition to the above-described resin, inorganic filler, curing agent, and curing accelerator, various additives can be added to the mixture containing as the main components as necessary.

Examples of such additives include inorganic pigments,
Examples include organic pigments, flame retardants, flame retardant aids, silane coupling agents, antifoaming agents, mold release agents, thixotropy improvers, surface smoothness improvers, fluidity improvers, and the like.

The electric iron core referred to in the present invention refers to a rotor or stator of a rotating electric machine, an iron core of a transformer, etc., and does not necessarily have a slot portion, and also includes a rotor of a coreless motor.

The coating layer formed on the surface of the electric iron core with this mixture usually has a thickness of 100 to 500 microns, is melted and hardened by heating, and is a strong three-dimensionally crosslinked insulating coating layer.

The method for producing an electric iron core having a high heat-resistant insulation coating in the present invention includes the silicone-modified epoxy resin (A) and the inorganic filler containing low melting point glass powder (B).
This is done by making a powder composition out of a mixture whose main constituents are, adhering it to the surface of an electric iron core, and then heating, melting and curing it to form an insulating coating.

As a method for attaching the powder composition to the surface of an electric iron core, the powder composition is suspended with compressed air and placed in a layer kept in a fluid state at a temperature higher than the melting point of the powder composition. A fluidized dipping method in which a heated electric iron core is immersed in water, the powder composition is fused to the surface of the iron core, and then heated to form a hardened insulating coating.The powder composition is immersed in compressed air. The powdered composition is made into a fluid state by spraying the powdered composition together with compressed air from a spray nozzle onto the surface of a rotating heated electric iron core to fuse the powdered composition to the surface of the iron core, Thereafter, a hot spray method is used in which a hardened insulating coating is formed by heating.

In addition, the powder composition in a fluid state charged by a high-voltage electrode is attached to the surface of a grounded electric iron core by electrostatic force, and then heated, melted, and hardened to form an insulating coating. Fluidized dipping method, in which the powder composition is sprayed with compressed air from a spray nozzle equipped with a high voltage electrode onto a grounded electric iron core, adhered to the surface of the iron core by electrostatic force, and then heated, melted, and hardened. An electrostatic spray method is also used in which an insulating coating is formed by spraying.

The powder composition used in the method of the present invention contains the silicone-modified epoxy resin (A) and the inorganic filler containing low melting point glass powder (B) as main components, and has a weight ratio of (A):(B). = Consists of 20:80 to 60:40,
And the content of particles with a particle size in the range of 10μ to 150μ is
It has a particle size distribution of 90% by weight or more.

There are many particles with a particle size of less than 10μ, and the particle size is 10μ or more.
If the content of particles in the 150μ range is less than 90% by weight, the particles will become densely packed together when the powder composition is fluidized with compressed air in the fluidized dipping method or hot spray method. This is undesirable because it makes it difficult for air to escape, causing bumping and scattering to the surroundings.Also, in the case of electrostatic dynamic immersion method, electrostatic spray method, etc., when high voltage is applied, static electricity accumulates on the particle surface. Since the amount is proportional to the volume of the particles, the electrostatic force becomes weaker and it becomes difficult to adhere to the grounded electric iron core, which is not preferable.

In addition, there are many particles with a particle size of over 150μ, and the particle size
When the content of particles between 10μ and 150μ is less than 90% by weight, in the case of fluidized dipping method and hot spray method,
When fluidizing the powder composition with compressed air,
As the particles become heavier, they become difficult to flow, which is particularly undesirable in the case of the hot spray method, as this can cause clogging of the nozzle of the spray gun, and in the case of the electrostatic dynamic dipping method and electrostatic spray method, the particles become difficult to flow. This is undesirable because it becomes heavy, and after the powder composition is adhered to the surface of the electric iron core by electrostatic force, the powder composition tends to fall off from the surface of the iron core due to the weight of the particles.

An example of a method for producing the powder composition is to use the above-mentioned silicone-modified epoxy resin.
Raw materials such as (A), inorganic filler containing low melting point glass powder (B), hardening agent, hardening accelerator, additives, etc. are rolled,
Examples include a method of melt-kneading with a screw extruder, Busco kneader, etc., then crushing with a crusher, and then removing coarse particles with a sieve or the like.

Next, a method for manufacturing an electric iron core having a highly heat-resistant insulation coating using the powder composition will be described in more detail.

When applying a highly heat-resistant insulation coating to an electric iron core using the powder composition by a fluidized dipping method or a hot spray method, the electric iron core is heated in a temperature range of 120°C to 240°C, particularly preferably 170°C to 240°C. Preheat in the temperature range of 200℃.

In the fluidized dipping method, the powder composition charged in a fluidized dipping tank is suspended by sending compressed air from the bottom of the tank partitioned by a perforated plate, so that the powder composition and air are mixed in a volume ratio of 95: The powder composition is maintained in a fluid state within a mixing ratio of 5 to 10:90, and a preheated electric iron core is immersed in the layer to fuse the powder composition to the surface thereof.

In the hot spray method, the powder composition and compressed air are sprayed at a mixing ratio of 95:5 to 10:90 by volume, and a preheated electric iron core rotating from a spray nozzle is used. By spraying the powder composition onto the surface of the powder, the powder composition is fused onto the surface of the powder composition.

Thereafter, these are heated in a temperature range of 150° C. to 230° C. to harden the powder composition and form an insulating coating.

The device for preheating the electric iron core may be a heating furnace such as an oven, a far-infrared furnace, or a high-frequency heating device. If the preheating temperature is below 120°C, it becomes difficult for the powdery composition to adhere to the surface of the iron core, resulting in poor productivity.If the preheating temperature is above 240°C, the fused powdery composition rapidly Unfavorable because it hardens and foams. Setting the preheating temperature to a range of 170°C to 200°C is most preferable since both productivity and coating appearance are good.

The mixing ratio of the powder composition and air is preferably 95:5 to 10:90 by volume in both the fluidized dipping method and the hot spray method.

When the mixing ratio of the powder composition exceeds 95% by volume, the powder composition hardly flows in the fluidized dipping method, and the powder composition hardly flows in the hot spray method due to an insufficient amount of air. In either case, the coating tends to be uneven because the composition does not completely form into a spray. If the mixing ratio of the powder composition is less than 10% by volume, the fluidized dipping method is not preferred because the amount of air is too large and the powder composition scatters around.
In addition, the hot spray method is not preferred because the amount of air is too large and the heated iron core cools down rapidly, making it impossible for the powder composition to fuse to the surface of the iron core.

The immersion time in the fluidized immersion method and the spray time in the hot spray method are determined by the thickness of the insulating layer formed on the surface of the iron core, and the film thickness is usually 100μ to 500μ.
The conditions are set to fall within the range.

If the film thickness is less than 100μ, the insulation layer is too thin and insulation tends to be insufficient.If the film thickness is more than 500μ, the space in the iron core slot becomes narrow, making it difficult to wind the wire a specified number of times. This is not preferable because the space factor tends to decrease, such as not being able to do so.

The curing of the powder composition fused to the surface of the iron core is as follows:
In both the fluidized immersion method and the hot spray method,
The heating is preferably carried out in a temperature range of 150°C to 230°C, particularly preferably in a temperature range of 180°C to 200°C, and the heating time is appropriately selected depending on the practical characteristics required of the insulating coating layer.

As a heating method, a heating furnace such as an oven furnace or a far-infrared furnace, a high frequency heating device, etc. are used. In addition, if the electric iron core used has a large heat capacity and the powder composition has fast curing properties, cooling of the iron core is slow, so heating of the iron core after painting is difficult. It is possible to harden the powder composition by allowing it to cool naturally without carrying out. That is, the temperature of the iron core does not fall below 150°C within 3 to 4 minutes immediately after coating, and the temperature of the powdered composition does not fall below 165°C.
If the gelation time on a hot plate is 100 seconds or less, there is no need to heat the coating after coating, and the coating can be cured by simply letting it cool naturally.

When applying a highly heat-resistant insulation coating to an electric iron core using the powder composition by an electrostatic dynamic dipping method or an electrostatic spray method, in either case, it is preferable to generate a voltage of 10 KV or more at a high voltage electrode. Then, static electricity is charged on the surface of the powder composition, and the mixture ratio of the powder composition and air is set to 95:5 to 5:95 by volume, and the powder composition is brought into contact with a grounded electric iron core to remove the static electricity. The powdered composition is applied to the surface by force. Preferably, this is then heated in a range of 150°C to 230°C to melt and harden the powder composition to form an insulating coating on the surface of the iron core.

When the voltage is less than 10 KV, the amount of static electricity stored on the particle surface of the powder composition becomes small, making it difficult for the powder composition to adhere to the surface of the grounded iron core. Furthermore, if the mixing ratio of the powder composition exceeds 95% by volume, in any coating method, the charged particles of the powder composition will fall onto the surface of the grounded electric iron core. Since the paint is applied all at once, the paint is applied in an extremely short period of time, so the paint tends to be uneven.

In addition, if the mixing ratio of the powder composition is less than 5% by volume, in any of the above coating methods, the charged particles of the powder composition will be deposited on the surface of the grounded electric iron core. It takes a long time to adhere a predetermined amount, which tends to reduce productivity.

The coating time for the above coating method is determined by the thickness of the insulating layer formed on the surface of the iron core, and for the same reason as the fluidized dip method and hot spray method, the film thickness is in the range of 100μ to 500μ. It is preferable to set the condition to be yes.

If the film thickness is less than 100μ, the insulating layer is too thin and insulation tends to be insufficient.If the film thickness is more than 500μ, the slot space becomes narrow and it becomes difficult to wind the wire the specified number of times. easy.

Heating, melting, and hardening of the powdery composition adhered to the surface of the iron core can be carried out by electrostatic dynamic dipping, electrostatic spraying,
In either case, heating is preferably carried out in a temperature range of 150°C to 230°C, particularly preferably in a temperature range of 180°C to 200°C, and the heating time is appropriately selected depending on the practical properties required of the insulating layer. Ru.

As the heating device, a heating furnace such as an oven furnace or a far-infrared furnace, a high frequency heating device, etc. are used. In addition, the electric iron core used has a large heat capacity, and
When the powder composition has fast curing properties,
Since the iron core cools slowly, the iron core is instantaneously heated using a high-frequency heating device, etc. to raise the iron core temperature to 180℃~200℃,
The powder composition can then be cured by allowing it to cool naturally.

That is, the temperature of the iron core does not fall below 150°C within 3 to 4 minutes immediately after raising the iron core temperature to 180°C to 200°C, and the gelation time of the powder composition on a hot plate at 165°C is If the time is less than 100 seconds, it can be cured simply by instantaneous heating using a high-frequency heating device or the like, and then allowing it to cool naturally.

The electric iron core has an insulating coating layer made of a hardened mixture of a silicone-modified epoxy resin (A) and an inorganic filler containing low melting point glass powder (B) as main components obtained by the present invention. It has the excellent feature that it has very good working efficiency and that the insulation does not deteriorate for a long time even at temperatures of 500 to 600°C under high load.

That is, the mixture containing the silicone-modified epoxy resin (A) and the inorganic filler containing low melting point glass powder (B) as the main components used in the present invention is an epoxy resin with good adhesiveness and flow characteristics when melted. Because we use a silicone-modified epoxy resin that is partially modified with an organic silicone intermediate that has good heat resistance, the resulting insulating coating layer has good adhesion and good flow characteristics, which are the characteristics of epoxy resin. , its surface is smooth and it has good adhesion to the iron core, so when it is wound on the insulating coating layer, the winding slips easily and high-speed winding is possible, and it also has good adhesion to the iron core. is good, so
Due to the tension during winding, cracks in the insulation coating layer,
No peeling occurs, and work efficiency during winding is good.

In addition, the insulating coating layer obtained from the mixture has good heat resistance for a long time in the temperature range from room temperature to around 350°C, due to the good heat resistance that is a characteristic of organic silicone intermediates, and has good heat resistance for a long time in the temperature range from room temperature to around 350°C. From 500 to 600℃
In the temperature range of 500℃ to 600℃ from room temperature, the inorganic substance with silicon-oxygen bonds that remains after the organic silicone is thermally decomposed, the inorganic powder, and the low melting glass that begins to soften and melt become enameled.
It has good heat resistance over a wide temperature range of ℃.
In other words, organic silicone thermally decomposes and silicon-
350℃ remaining as an inorganic substance with oxygen bonds
In the temperature range of 500 to 600℃, only this inorganic substance remains, although the silicon-oxygen bond skeleton remains.
The mechanical strength of the insulating layer is extremely weak if only this inorganic substance and inorganic powder are used, but it
If there is a low-melting point glass powder that softens and melts in the temperature range of 650℃, it will act as a binder with the inorganic substance and inorganic powder, and only when these are integrated into enamel will it have heat resistance at high temperatures. It will become.

In addition, in the present invention, a powder composition containing a silicone-modified epoxy resin (A) and an inorganic filler containing low melting point glass powder (B) as main components is prepared by a fluidized dipping method, a hot spray method, or an electrostatic movement method. Under specific conditions using powder coating methods such as dipping and electrostatic spraying,
The insulating coating layer is formed by attaching it to the surface of the electric iron core and melting and hardening it by heating. According to the manufacturing method of the present invention, the insulating treatment can be easily performed.
Moreover, the advantage of powder coating method, which is high productivity and low product cost, is not diminished in any way, but rather is enhanced.

In other words, the powder coating method is preferable in terms of hygiene and safety because it does not use harmful organic solvents, compared to the method of applying insulation coating in the form of varnish using a solvent.
Further, since volatile matters such as solvents are hardly present in the insulating layer, deterioration such as foaming of the insulating layer is less likely to occur even at high temperatures, and an insulating layer having excellent heat resistance can be obtained, which is preferable.

The present invention will be explained below with reference to Examples.

Manufacturing example 1 A powder composition was produced as follows.

Prescription Silicone-modified epoxy resin [25% by weight of bisphenol-type epoxy resin modified with a methoxy group-containing silicone intermediate. Melting point: 70°C Epoxy equivalent: 1300-1350〕 45 parts Low melting point glass powder (melting point: 410°-430°C) 30 parts Silica powder 15 parts Alumina powder 9 parts Inorganic pigment (red iron) 1 part Dicyandiamide (Epicure 108FF manufactured by Ciel Chemical Co., Ltd.) ) 3 parts After rolling and kneading the above mixture, pulverizing it with a pulverizer and removing coarse particles with a sieve, the content of particles with a particle size in the range of 10μ to 150μ is 93% by weight.
A silicone-modified epoxy resin powder composition containing low melting point glass powder was obtained having a particle size distribution of .

Manufacturing example 2 A powder composition was produced as follows.

Prescription: Silicone-modified epoxy resin [35% by weight of a mixture of bisphenol-type epoxy resin and novolac-type epoxy resin using a hydroxyl group-containing silicone intermediate.
degenerated. Melting point 58℃, epoxy equivalent 850~
870] 35 parts low melting point glass powder (melting point 450° to 470°C) 25 parts silica powder 34 parts alumina powder 5 parts inorganic pigment (red iron) 1 part imidazole (2-phenylimidazole manufactured by Shikoku Kasei Co., Ltd.) 0.7 parts Above The mixture was kneaded using a twin-screw extruder, pulverized using a pulverizer, and coarse particles were removed using a sieve. A silicone-modified epoxy resin powder composition containing a low melting point glass powder having a particle size distribution was obtained.

Manufacturing example 3 A powder composition was produced as follows.

Prescription Bisphenol type epoxy resin (melting point 96℃, epoxy equivalent weight 900-950) 30 parts Novolac type epoxy resin (melting point 80℃, epoxy equivalent weight 170-180) 20 parts calcium carbonate powder 49 parts inorganic pigment (red iron) 1 part imidazole (2-Phenylimidazole, manufactured by Shikoku Kasei Co., Ltd.) 2 parts After kneading the above mixture in a Busco kneader, pulverize it in a pulverizer, remove coarse particles with a sieve, and
A silicone-modified epoxy resin powder composition containing low melting point glass powder was obtained, having a particle size distribution in which the content of particles in the range of 10μ to 150μ was 93% by weight.

Manufacturing example 4 A powder composition was produced as follows.

Prescription Silicone-modified epoxy resin [40% by weight of a mixture of bisphenol-type epoxy resin and novolak-type epoxy resin modified with a methoxy group-containing silicone intermediate. Melting point 62℃, epoxy equivalent 900
~940] 40 parts high melting point glass powder (melting point 550°C to 580°C) 27 parts silica powder 16 parts alumina powder 10 parts inorganic pigment (red iron) 1 part imidazole (2-phenylimidazole, manufactured by Shikoku Kasei Co., Ltd.) 1 After kneading the above mixture in a Busco kneader,
Grind with a grinder, remove coarse particles with a sieve, and check the particle size.
The content of particles in the range of 10μ to 150μ is 95%.
A silicone-modified epoxy resin powder composition containing high melting point glass powder was obtained having a particle size distribution of % by weight.

Example 1 The powder composition obtained in Production Example 1 was used to insulate the surface of an electric iron core by a fluidized dipping method to obtain an insulating layer with good smoothness.

The coating conditions and deposited film thickness are as follows.

The electric iron core was preheated in an oven at 200° C. for 30 minutes, and was immersed for 3 seconds in a fluidized immersion bed containing the above powder composition to fuse the powder composition to the surface of the iron core.

Next, this is heated in an oven at 200℃ for 20 minutes to melt and harden the powder composition, and it is applied to the surface of the iron core.
An insulating layer with a thickness of 300μ was formed.

Winding was performed on this insulating layer at high speed, and then assembled with other parts to create a rotating electrical machine.

Since the insulating layer obtained by powder coating was smooth, the winding had good sliding and high-speed winding was possible, and there was no cracking or peeling of the insulating layer during winding. The work efficiency was very good.

The rotating electrical machine is operated, and then the rotating shaft is fixed so that it does not move, keeping it in a so-called locked state, and the internal temperature of the rotating electrical machine is raised to 500°C to 600°C in about 2 to 3 minutes, and it is kept in that state for 100 hours. Although the temperature was maintained, no insulation failure occurred at all.

After disassembling the rotating electric machine and examining the condition of the insulating layer, it was found that it had become enameled and had become a strong coating.

The situation was as shown in Figure 4.

Example 2 Using the powder composition obtained in Production Example 2, an electric iron core was insulated by a hot spray method to obtain an insulating layer with good smoothness.

The coating conditions and deposited film thickness are as follows.

The electric iron core is preheated using a high-frequency heating device until the temperature of the iron core reaches 230℃, and while the iron core is rotated once every 3 seconds, sprayed powder is sprayed onto the surface of the iron core from a nozzle for 10 minutes. The powder composition was sprayed for seconds to fuse the powder composition to the surface of the iron core.

After that, the powder composition is melted and hardened by allowing it to cool naturally without heating, and it forms on the surface of the iron core.
An insulating layer with a thickness of 350μ was formed.

As a result of assembling the motor in the same manner as in Example 1 and testing it in the same manner, the internal temperature of the rotating electrical machine was
Even when the temperature was raised to 500°C to 600°C and held for 100 hours, no insulation defects occurred at all, and when the rotating electric machine was subsequently disassembled and the condition of the insulating layer was examined, it was found that it had become enameled and had become a strong coating film.

The situation was similar to that shown in Figure 4.

Example 3 The powder composition obtained in Production Example 1 was used to insulate the surface of an electric iron core by an electrostatic dynamic dipping method to obtain a layer on the surface of an insulated electric iron core with good smoothness.

The above powder composition was charged into an electrostatic dynamic dipping bath, and the powder composition was brought into a fluid state with compressed air of 0.5 Kg/ ^cm2 , and 50 KV was applied to the high voltage electrode in the electrostatic dynamic dipping bath. A high voltage was applied to charge the particles of the above powder composition.

Thereafter, the grounded electric iron core was held above the electrostatic dynamic dipping tank for 50 seconds to adhere the powder composition to the surface of the iron core.

This is then heated in an oven at 200°C for 20 minutes to melt and harden the powder composition, which is then applied to the surface of the iron core.
An insulating layer with a thickness of 300μ was formed.

Winding was performed on this insulating layer at high speed, and then assembled with other parts to create a rotating electrical machine.

Since the insulating layer obtained by powder coating was smooth, the winding had good sliding and high-speed winding was possible, and there was no cracking or peeling of the insulating layer during winding. The workability was very good.

The rotating electrical machine is operated, and then the rotating shaft is fixed so that it does not move, keeping it in a so-called locked state, and the internal temperature of the rotating electrical machine is raised to 500°C to 600°C in about 2 to 3 minutes and maintained in that state for 100 hours. However, no insulation defects occurred at all.

After disassembling the rotating electric machine and examining the condition of the insulating layer, it was found that it had become enameled and had become a strong coating.

The situation was as shown in Figure 4.

Example 4 The powder composition obtained in Production Example 2 was used to insulate the surface of an electric iron core by electrostatic spraying to obtain an insulating layer with good smoothness. The coating conditions and deposited film thickness are as follows.

The above powder composition is charged into an electrostatic spray tank,
Compressed air of 0.5Kg/ ^cm2 is brought into a fluid state, and when spraying from the spray nozzle at the top of the tank, a high voltage of 70KV is applied to the high voltage electrode at the tip of the spray nozzle to charge the powder composition particles. I let it happen.

Thereafter, the grounded electric iron core was held in an electrostatic spray tank for 70 seconds to allow powder to adhere to the surface of the iron core.

After that, the temperature of the iron core was raised to 230°C in 60 seconds using a high-frequency heating device, and then the powder composition was melted by allowing it to cool naturally without heating.
It was cured to form an insulating layer with a thickness of 350μ on the slot surface.

As a result of assembling the motor in the same manner as in Example 1 and testing it in the same manner, the internal temperature of the rotating electrical machine was
Even when the temperature was raised to 500°C to 600°C and held for 100 hours, no insulation failure occurred at all, and when the rotating electric machine was then disassembled and the condition of the insulating layer was examined, it was found that it had become enameled and had become a strong coating film. .

The situation was similar to that shown in Figure 4.

Comparative Example 1 Using the powder composition obtained in Production Example 3, powder coating was performed under exactly the same conditions as in Example 1.

Windings were formed on the insulating layer on the surface of the iron core obtained in this way, and then assembled with other parts to create a rotating electric machine.

The resulting insulating layer was smooth and the winding slid smoothly, but when winding was done at high speeds, the insulating layer was too hard and cracked and peeled, so the impact force applied to the insulating layer during winding was weakened. Therefore, it was necessary to wind the wire at an extremely low speed, and the work efficiency during winding was extremely poor.

In addition, when a rotating electric machine was started, the rotating shaft was fixed so that it would not move, and the rotating electric machine was kept in a so-called locked state, and the internal temperature of the rotating electric machine was rapidly raised, about 3 minutes later (the internal temperature of the rotating electric machine was about 500℃). Insulation failure occurred.

After disassembling the rotating electric machine and examining the condition of the insulating layer, only ash powder remained.

In addition, there were many places where the windings were in direct contact with the slots, resulting in incomplete insulation.

The condition was as shown in Figure 3.

Comparative Example 2 Using the powder coating obtained in Production Example 4, powder coating was performed under exactly the same conditions as in Example 3.

Winding wires were formed on the insulating layer on the surface of the iron core obtained in this way, and then assembled with other parts to create a rotating electric machine.

Since the insulating layer obtained by powder coating was smooth, the winding had good sliding properties and high-speed winding was possible, and there was no cracking or peeling of the insulating layer during winding. The workability was very good.

However, when a rotating electric machine is started and the rotating shaft is fixed so that it does not move and kept in a so-called locked state, the internal temperature of the rotating electric machine rapidly rises.
After 30 minutes (the internal temperature of the rotating electric machine was about 500℃), an insulation failure occurred.

After disassembling the rotating electric machine and examining the condition of the insulating layer, only ash powder remained.

In addition, there were many places where the windings were in direct contact with the slots, resulting in incomplete insulation.

The situation was as shown in Figure 3.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the state of insulation treatment of an electric iron core of a rotating electrical machine using the insulator method. FIG. 2 is a diagram showing an insulation treatment state formed by heating and melting an epoxy resin powder coating. FIG. 3 is a diagram showing the situation after the heat resistance test of Comparative Examples 1 and 2. FIG. 4 is a diagram showing the situation after a heat resistance test after insulation treatment according to the present invention. FIG. 5 is a schematic diagram showing an example of an electric iron core used in the present invention. In the figure, 1 is an electric iron core, 2 is a shaft, 3 is a wound copper wire, 4 is an insulator, 5 is an insulating layer formed by heating and melting epoxy powder paint, and 6 is an insulating layer formed by heating and melting epoxy powder paint. Ashy powder, 7 indicates an enameled coating film.

Claims (1)

[Scope of Claims] 1. An epoxy resin modified with an organic silicone intermediate having a functional group capable of reacting with an epoxy resin containing a hydroxyl group on the surface of an electric iron core in a range of 10 to 50% by weight and having a melting point of 40°C or higher. , the epoxy equivalent is 400
~2000 silicone-modified epoxy resin (A) and 400℃
10% by weight low melting glass with melting point of ~500℃
An electrical appliance characterized by having a coating layer made of a hardened mixture of (A):(B)=20:80 to 60:40 in a weight ratio of (A):(B)=20:80 to 60:40, the main component being an inorganic filler (B) containing the above. Iron core. 2 A melting point obtained by modifying an epoxy resin in a range of 10 to 50% by weight with an organosilicone intermediate having a functional group that can react with an epoxy resin containing a hydroxyl group.
40℃ or higher, contains silicone-modified epoxy resin (A) with an epoxy equivalent of 400 to 2000 and 10% or more of low melting point glass with a melting point of 400℃ to 500℃, and has an average particle size of
The main component is an inorganic filler (B) of 1μ to 60μ,
A powder composition having a weight ratio of (A):(B) = 20:80 to 60:40 and containing 90% by weight or more of particles with a particle size of 10μ to 150μ is used as an electric iron. A method for manufacturing an electric iron core having a highly heat-resistant insulation coating, which comprises adhering it to the surface of the core and then melting and hardening it by heating to form an insulation coating. 3. The method for manufacturing an electric iron core according to claim 2, wherein the method for applying the powder composition is a fluidized dipping method or a hot spray method. 4. The method for manufacturing an electric iron core according to claim 2, wherein the method for applying the powder composition is an electrostatic dynamic dipping method or an electrostatic spray method.