JPS6059614A - Lumped mica composite insulating material and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an insulating material, such as a tape, in which multiple layers of a sheet-like unimpregnated insulating body containing a composite mica material are combined with a resin, The present invention relates to an assembled mica composite insulating material which is impregnated with an impregnating resin and cured after being applied to or wound around an electric device or a part thereof, such as a power generation coil, and a method for manufacturing the same.

[Prior art and its problems]

A technique is known in which an unimpregnated insulating material as described above is applied to a predetermined location of an electrical device or its part, and then impregnated with an impregnating resin and cured to form an insulator with excellent characteristics.
When the insulating material is a composite insulating material containing laminated mica, there are problems such as difficulty in applying it to electrical equipment, such as winding it around a coil, and a short usable period of the insulating material. Ta.

In other words, if the amount of resin used to bond together the sheet-like insulating bodies that make up the composite insulating material, such as tape, is too large, the impregnation process becomes difficult and an insulator with good properties cannot be obtained. There is an upper limit to the amount of resin. However, if the amount of resin is reduced to be advantageous for impregnation, the strength of the insulating material will not be sufficient and the mica assembly will easily peel off, making the winding work etc. very troublesome. In addition, if the storage period of the insulating material is too long before it is applied to the device after manufacturing, the adhesive resin will harden and lose its flexibility, making the wrapping work more troublesome, and the final The properties of the resulting insulator also deteriorate.

Composite insulation materials containing laminated mica materials can exhibit excellent insulation properties as the main insulation or auxiliary insulation of equipment if they are applied properly and sufficiently impregnated with resin. However, there were problems with the construction and work that caused the unique characteristics of the reeds to not be fully utilized.

[Purpose of the invention]

The present invention solves the problems of the prior art as described above, and provides an unimpregnated composite mica composite insulating material that has good impregnability, a long shelf life, and is highly workable, and a manufacturing technology thereof. It is in.

[Key points of the invention]

According to the present invention, an insulating material that meets the above objectives is capable of curing reaction with the curing agent contained in the impregnating resin as an adhesive resin, does not contain a curing agent, and is solid at room temperature or storage temperature. When bonding a composite mica material and another sheet-like insulating body using a resin, powder of the resin is distributed in dots between the insulating bodies to be bonded together,
Further, by melting the resin powder, the insulating elements are bonded to each other at the distributed dot-like portions. As the above-mentioned adhesive resin, it is of course preferable to select one that is of the same type as the impregnating resin, has a higher degree of polymerization, and is solid at room temperature.

For example, if the impregnating resin mixture is a mixture of leuphoxy resin, which is a copolymer of epichlorohydrin and bisphenol, and a liquid acid anhydride-based curing agent, the adhesive resin may be a mixture of the same type of impregnating resin as the adhesive resin. A so-called Ebisu-based epoxy resin with a high degree of polymerization is used in a form that does not contain any curing agent. Since the adhesive resin in the composite insulating material exists as a powder adhesive resin distributed in a dotted manner, the reaction area with the hardening agent in the impregnated resin mixture is small, and when heated, the adhesive resin immediately reacts with the hardening agent. A hardening reaction occurs with the impregnating resin, resulting in a cured resin with good properties that is completely integrated with the impregnating resin.

In addition, since the adhesive resin is only distributed in dots in such an insulating material, it does not become an obstacle during impregnation work.
A composite insulating material with very good resin impregnation properties can be obtained. In addition, in the composite insulating material, the resin powder only melts at the point of contact with the insulating material and bonds the elements together, and does not penetrate into the interior of the element, so a relatively small amount of resin is required. For example, sufficient adhesive strength can be obtained with an amount of resin of about 5 grams per square meter of adhesive surface. The size of the resin powder is preferably 50 mesh or less, and the above-mentioned amount of resin is practically 3 to 8 Ii per square meter of the adhesive surface from the viewpoint of adhesive strength and impregnability.

Next, the manufacturing method of the laminated mica composite insulating material that meets the above purpose is to indirectly sprinkle powder onto the upper surface of the laminated mica sheet to be bonded to the insulating element from the surface opposite to the resin grains by a powder scattering method. At the same time as heating and melting, another sheet-like insulating element to be bonded is placed on a heated roller from the outside of the composite mica sheet, and is pressed against the composite mica sheet using the tension in the insulating element. , whereby the mica sheet assembly and the other insulating element are bonded to each other by the molten resin powder. At this time, it is necessary to perform the adhesion only in distributed or line-dispersed point-like areas, so when the resin powder is melted, #Y simultaneously presses another insulating element to perform the adhesion, It is important to complete the adhesion while preventing the molten resin from penetrating into the insulating element, especially the composite mica sheet, as much as possible. The other insulating element to be bonded to the mica sheet assembly may be a thin non-woven fabric or a mica sheet assembly.

In addition, as a method of scattering resin powder on the surface of the laminated mica sheet, a scattering roller having fine irregularities on the surface is rotated in a powder tank storing the resin powder, and the powder adhered to the uneven surface of the scattering roller is rotated. A method in which the amount of resin is adjusted to a specified amount using a doctor blade method, and then the resin powder adhering to the surface is pulled out or knocked out using an electrostatic repulsion device at the spraying port allows the appropriate amount of resin powder to be uniformly spread over a wide area. It is good in terms of

[Embodiments of the invention]

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

FIG. 1 shows equipment for manufacturing a composite insulating sheet or tape 1 in which a mica sheet assembly 2 and a thin nonwoven fabric 3 as an insulating element are bonded together by molten resin particles 4a as shown in FIG. This shows the arrangement, as shown in Figure 10.11.
are delivery reels for feeding out the laminated mica sheet 2 and the nonwoven fabric 4, respectively, and the reels are appropriately braked by known means, so that the laminated mica sheet and the nonwoven fabric fed out from these reels are A tension suitable for each element body is applied to. As a laminated mica sheet, for example, 0.1 mm thick per square meter
A wide sheet having a weight of 1 gram may be used, and as the composite mica material, a known unfired composite mica material is advantageous from the viewpoint of impregnability and insulation properties.

It is also advantageous for such a composite mica material to previously contain an accelerator that accelerates the curing of the impregnating resin. In addition, as a non-woven fabric, for example, the thickness of about 0.04 fin is 1
Non-woven fabrics made of wide polyester fibers having a weight of around J) 18.5 grams per square meter are suitable as reinforcing materials. Of course, it is advantageous for both the assembled mica sheet 2 and the nonwoven fabric 3 to be unimpregnated in order to facilitate resin impregnation.

The assembled mica sheet 2 sent out from the delivery reel 10 is passed over an idle roller 12, and in the vicinity of this, resin powder 4, which has been spread by a powder spreader 20 to be described later, is spread on its upper surface. As the resin material, for example, the above-mentioned Epivis-based epoxy resin with a high degree of polymerization having a softening point of about 94 degrees C is used, and powder having a particle size of about 50 mesh or less is used. The doctor blade of the powder spreader 20 is adjusted so that the amount of powder spread is, for example, 5 grams per square meter. The amount of spraying varies depending on the properties of the insulating bodies to be bonded, especially their surface roughness, but in general, a suitable amount is 3 to 8 grams per square meter of one side of the adhesive.

Laminated mica sheet 2 sprinkled with powdered resin 4 in this way
is applied to the heating row 213'. This heating roller is heated to a surface temperature of 130, for example, by steam heating or electric heating.
It is configured as a drive roller heated to 50°C. Of course, this surface temperature needs to be above the softening point of the resin.
The temperature value should of course be adjusted depending on the thickness of the laminated mica sheet and the driving speed, but if the thickness of the laminated mica sheet is about 0.1+IIK and the peripheral speed of the roller is 3 m/torr/
In the case of about 1 minute, a temperature of about 130 degrees Celsius is appropriate, and a range of about 5 degrees Celsius above and below that is acceptable. If the thickness of the mica sheet or the circumferential speed of the roller differs, the temperature of the heating roller must of course be changed, but generally the temperature is 1° below the softening point of the resin.
It is practical to choose a value 0 to 50 degrees higher.

Since the heating roller 13 is pressed and attached by the above-described delivery row 211, the mica sheet assembly 2 and the nonwoven fabric 3 are bonded to each other within a very short time.

To finely adjust the timing of resin powder melting and adhesion, the position of the axial support point of the delivery roll 11 is made variable in the direction of arrow A in the figure, so that the position or angle at which the nonwoven fabric 3 is applied to the heating roller 13 can be adjusted. It is convenient to keep it.

After being completely cooled, it is wound onto a take-up reel 17 via idlers 15 and 16. The take-up reel is of course constructed as a drive reel.

The composite insulating sheet 1 manufactured as described above has a thickness slightly smaller than the sum of the thicknesses of the combined insulating elements.゛Nose application. 5 matches. , □about 46.8.

It has a tensile strength of about 1.35 to 9 when converted to a tape with a width of 15+n. The range of variation in thickness is about ±5%, and the variation in tensile strength is about ±10%. Furthermore, when the adhesive content was measured by dividing the sheet into a large number of small pieces, an in-plane variation of more than ±20% was observed.

Next, the means for dispersing the powder will be explained with reference to FIG. The figure shows a cross-section of a powder spreader 20 used to fabricate a sample of an embodiment of the present invention, and a powder spreader 20 having such a cross-section and whose total length is approximately equal to the width of the assembled mica sheet is used.

In this powder spreader, resin powder 4 as a raw material is stored in a powder tank 21. The powder tank 21 has left and right side walls 21a,
21b and front and rear side walls 21d, the upper opening is covered by an openable and closable cover 21c.

A spraying row 222 extending in the longitudinal direction is housed in the tank, and is mechanically coupled to a motor 23 supported on the side wall 21dK, so that the spraying row 222 is rotated slowly nine times in the direction of the arrow in the figure. The dispersion roller 22 is provided with unevenness 22a on its circumferential surface.
Spreading roller:) With the rotation of 220 revolutions, the powdered resin 4 in the tank falls into the four parts, adheres to the spreading roller, and is taken out one after another, forming a trap.

In order to make the surface of the scattering row 222 uneven, it is best to provide spiral cross grooves with a depth of 1 diameter and a roughness of about 10 mesh, so that the surface is formed into a rough file shape. Ru.

The gap on the left side of the figure between the lower opening of the powder tank 21 and the scattering row 222 is closed by the doctor blade 24.
After the resin powder 4 attached to the doctor grade 24 and the dispersion row 222 is regulated to a specified amount, it is taken out of the powder tank at the bottom of the figure. The doctor blade 22 is preferably made of a flexible stainless steel plate with a thickness of about 0.2 m, and its mounting portion 24a is configured to be adjustable.

An electric wire 25 stretched between the front and rear side walls 21d is disposed below the spreading roller 22, and has a voltage of several thousand volts, for example, 400 volts.
A high direct current positive voltage of about 0 to 5000 volts is applied to this. The electric wire 25 may be, for example, a stranded wire of 2 diameters coated with insulation to have an outer diameter of 8jIII. Spreading row 2
22 is grounded together with the powder tank 21, so the electric wire 2
A strong electric field acts between 5 and the lower circumference of the scattering row 222, and the resin powder 4 is charged by this electric field, and the resin powder 4
It is repulsed from 2, taken out, and scattered downward.

The gap between the lower opening of the powder tank 21 and the scattering roller 22 on the right side in the figure is closed by a wiper blade 26 made of a stainless steel plate with a thickness of about 0.2 m, as before, and the electrostatic charge caused by the FIMz 5 is closed. This wiper blade 2 contains resin powder that was not removed even by the target extraction trap.
6, it is further mechanically extracted and distributed downwardly. Furthermore, another wiper blade 27 is disposed within the powder tank 21 and serves to scrape off the resin powder fixedly adhered to the circumferential surface of the scattering roller 22. This other wiper blade 27 is preferably made of an organic resin board, such as a polycarbonate board, which is highly elastic and has a thickness of 0.5 degrees, and the scattering row 222M has a slight difference in hardness. This wiper blade 27
This is extremely effective in preventing the powder resin from permanently adhering or adhering to the surface of the scattering roller and causing so-called clogging 9 in the uneven portion 22a, and allows the powder scattering machine to operate stably for a long period of time. Allows you to drive.

The resin powder scraped off from the circumferential surface of the v-spreading roller 22 by the wiper blade 27 is naturally mixed with the resin powder 4 in the powder tank 21 as the sprinkling roller rotates.

The laminated mica composite insulating material according to the present invention manufactured as described above has the above-mentioned strength, and visual inspection shows that there are no wrinkles or partial cuts in the mica layer that tend to occur in the laminated mica layer. Not observed and has a good surface. In addition, the adhesive strength is sufficient, and even if you cut a tape several tens of inches wide from the sheet produced as described above and wrap it around a coil, it will not peel off from the adhesive surface. Not at all. Furthermore, when the adhesive surface was forcibly peeled off and observed, almost no penetration of the molten powder resin into the mica layer was observed.

Next, experimental results on the resin impregnation properties of the composite insulating material according to the present invention will be explained. First, in order to test the impregnability of the composite insulating tape in the thickness direction, the tape was
10 pieces cut into 50m + 1 pieces are stacked, and 2 pieces are placed on top of this.
A metal frame of 0 x 45 am was mounted and a load of 0.2 kl+ was applied to the metal frame to apply pressure between the tapes.

Then, masking resin was poured to completely cover the cut surface of the tape as well as the entire surface of the tape exposed outside the metal frame. After heating the sample prepared in this way in a constant temperature bath at 70 degrees Celsius,
Approximately 20 grams of colored epoxy-based impregnated resin that had been heated to 0 degrees Celsius was injected into a metal frame and held at the above constant temperature bath temperature for 30 minutes, after which the specimens were disassembled and stacked. The state of impregnation of the resin into the tape layer was determined based on the state of coloring.

FIG. 4 is a photograph showing this result, in which A shows a composite mica tape according to the present invention, and B shows the same type of tape manufactured by the prior art. As shown in the figure, tape A according to the present invention is impregnated with resin up to five layers,
It can be seen that the resin impregnation property is more than twice as good as that of the conventional tape B which is impregnated with only two layers.

Next, in order to test the impregnability of the solvent in the direction parallel to the surface of the insulating sheet, the tape with a width of 15 mm was cut into lengths of 150 mm, and the ends of the cut tape were coated with ethyl dye colored with red dye. The material was immersed in Cellosolve M and the relationship between the immersion time of the end and the height of absorption of Cellosolve was measured based on the state of coloration. As shown in the graph of the result line in FIG. 5, it is recognized that tape A according to the present invention is clearly superior to tape B according to the prior art in terms of solvent impregnation properties in this test as well. In this graph, the horizontal axis indicates the immersion time of the end in the solvent, and the vertical axis indicates the penetration height of the solvent.

Furthermore, in order to experiment with the impregnability of the taped insulating layer using the insulating material of the present invention, two layers of taping were applied to a 2 meter long simulated coil of aluminum pipe with a diameter of 30 mm using an I/2 ship, and the outside of the taped layer was The model coil was sealed with polyester heat-shrinkable tubing and one end of the model coil was pierced with epoxy resin to create a test piece that was completely closed except for the other end. Next, an epoxy resin for impregnation was vacuum-impregnated from the other end of the test piece under the conditions of a vacuum degree of 0.2 m HE and a temperature of 75 degrees C, followed by pressure impregnation treatment for 10 minutes, and the resin was applied to the test piece. The impregnation length was observed. The sixth factor is a photograph showing the impregnated state of this test piece. From now on, the test piece made of insulating material A according to the present invention will have better resin impregnation than the test piece made of conventional material B. I know that there is.

In order to verify the electrical properties of the insulator using the insulating material according to the present invention, the above-mentioned tape was wrapped five times in half laps on a 1 meter long aluminum bar having a cross section of 10 x 50 fins as a model coil. A test specimen was fabricated.

This specimen was placed in a mold with dimensions so that the insulation thickness was 1.5 m, and with the insulation layer slightly pressed, the epoxy resin for impregnation was impregnated with vacuum pressure under the same conditions as above. ,
It was heat-cured as it was. This model coil was subjected to a specified end discharge prevention treatment, and then its dielectric voltage was cut off (tlIδ
) was measured. FIG. 7 is a graph 27 showing the relationship between this result and the applied voltage. As can be seen from the figure, the model coil using insulating material A according to the present invention is different from the model coil using material B according to the prior art. In the voltage range up to 10 KV, there is no significant difference in dielectric voltage cut, but at high voltages of 1Oxv or higher, the dielectric voltage cut is clearly lower than that of model coil B, and due to good impregnation, defects such as voids may occur in the insulating layer. This shows that there are few In addition, we investigated the dependence of dielectric voltage cut on temperature for the same model coil, but
It turns out that there is no big difference between Sodelcoil A and B. The fact that there is no significant difference in this temperature dependence is due to the fact that the resin that does not contain any curing agent used for adhesion of the composite insulating material according to the present invention reacts well with the curing agent in the impregnated resin, and the uncured resin This shows that there is almost no remaining in the insulating layer.

〔Effect of the invention〕

In the laminated mica composite insulating material according to the present invention, as described above, the adhesive resin is only distributed in dots within the bonded surfaces of the insulating elements, so the adhesive resin does not penetrate into the unimpregnated insulating elements. There is virtually no impediment to the penetration of the impregnating resin, and therefore the resin impregnating properties are very excellent. In addition, the adhesive resin adheres the insulating elements to each other by melting, and it hardly penetrates into the element, especially into the mica material, so that a smaller amount of resin than before can be used to bond the insulating elements with sufficient adhesive strength. It is possible to obtain an insulating material with good workability that is suitable for application to various types of equipment. moreover,
Since the adhesive resin does not contain any curing agent, there is no risk of curing at room temperature or within the storage temperature range, and the shelf life of the composite insulating material can be extended until there is no practical problem. Moreover, it contains this hardening agent and can be bonded for 1 m.
Since the fat is in powder form, it can quickly undergo a curing reaction with the curing agent in the impregnated resin, resulting in complete curing.

In the method for producing a laminated mica composite insulating material according to the present invention, almost at the same time as the powdered resin sprinkled on the laminated mica sheet is melted on the heating roller, the laminated mica-K adhesive body is converted into molten resin powder. Since it is pressed and bonded immediately, it is unlikely that the resin will penetrate into the insulating body, especially into the laminated mica layer, and the extremely small amount of resin will provide sufficient adhesive strength for the work, making it suitable for application to equipment. As mentioned above, an insulator having both excellent workability and performance can be obtained. Furthermore, the method of the present invention does not require any special equipment other than a powder spreader, and a large amount of composite insulating material can be produced at relatively high speed with inexpensive equipment.

As explained above, the composite insulating material and its manufacturing method according to the present invention can make a significant contribution to the development of the industry by providing a novel technology and an insulating material with excellent performance. .

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of equipment for manufacturing the laminated mica composite insulating material according to the present invention, FIG. 2 is a sectional view showing a resin powder spreader in the equipment shown in FIG. 1, and FIG. The figure is a cross-sectional view of the laminated mica composite insulating material according to the present invention, Figure 4 is a photograph showing the results of an impregnation test of the resin for impregnating the insulating material of the present invention, and Figure 5 is a photograph showing the results of the impregnation test of the resin for impregnating the insulating material of the present invention. Figure 6 is a photograph showing the results of an impregnating resin impregnation test on a model coil using the insulating material of the present invention, and Figure 7 is a graph showing the results of a model coil using the insulating material of the present invention. FIG. 2 is a graph diagram showing the relationship between coil voltage and dielectric voltage cutoff. In the figure, 1: laminated mica composite insulating material, 2: laminated mica sheet, 3: nonwoven fabric as an insulating element, 4: resin powder, 4a:
Molten resin powder, 13: heating roller, 20: powder scattering machine,
21: Powder tank, 22: Spreading roller, 22a: Spreading row 2
Irregularities on the circumferential surface, 24: doctor blade, 25: electric wire to which high voltage is applied as electrostatic repulsion means, 26.27: wiper blade. Figure 2 Figure 3 g Procedural amendment (force,・“・,) Showa, ', 170 Special I/L Office Director-General Wakaisugi J1 Husband 3, Person making the amendment 1111'ltsu , Relationship to the case 4, Contents of the agent's amendment (1) From "Figure 4 is ..." in the first line of page 24 of the specification,
The lines up to "It is a graph diagram." in the 8th line of the same page are corrected as follows. Figure 4 is a graph showing the results of a test on the penetration of a solvent into the insulating material of the present invention, and Figure 5 is a graph showing the relationship between voltage and dielectric voltage cutoff of a model coil using the insulating material of the present invention. (2) Figures 4 and 6 are deleted. (3) Correct Figure 5 as Figure 4, and Figure 7 as Figure 5.

Claims (1)

[Scope of Claims] Technique) A sheet-like unimpregnated insulating body containing a laminated mica material is made of resin in multiple layers, and is cured after being applied to a predetermined location of an electrical device or its part. In a composite insulating material that is impregnated with an impregnating resin containing an impregnating agent, the particles of the resin, which are solid at room temperature in a state where it is possible to react with the curing agent in the impregnating resin and do not contain the curing agent, A laminated mica composite insulating material characterized in that the insulating elements are interposed in a distributed manner between the li and materials, and the insulating elements are bonded to each other only in the distributed dot-like parts by melting the resin powder. . 2. The insulating material according to claim 1, wherein the adhesive resin is an epoxy resin. 3) The laminated mica composite insulating material in the insulating side slope according to claim 1, characterized in that the resin powder is powder with a particle size of 50 mesh or less. 4) The insulating material according to claim 1, characterized in that the amount of adhesive resin is 3 to 8 grams per square meter of adhesive surface. 5) The insulating material according to claim 4, characterized in that the amount of adhesive resin is about 5 grams per square meter of adhesive surface. 6) The insulating material according to claim 1, wherein the insulating element includes a thin nonwoven fabric. 7) The composite mica insulating material according to claim 1, wherein the mica composite material is unsintered mica composite. 8) A composite mica insulating material according to claim 1, characterized in that the composite insulating material is formed as a tape. 9) A method for producing a composite insulating material in which a plurality of unimpregnated sheet-like insulating elements containing a composite mica material are bonded to each other at dot-shaped areas distributed by molten powder resin. The process includes a step of spraying resin powder from above onto the bonding surface of the composite mica sheet to be bonded to another insulating element, and after the spraying step, heating the composite mica sheet to a temperature above the softening point of the resin. a step of heating and melting the dispersed resin powder from the surface opposite to the bonding surface of the assembled mica sheet by wrapping it around a heating row 2 having a heating row 2; and simultaneously assembling the other insulating element body in the heating step wrapping the mica assembly from the outside around a heated roller in the presence of tension so as to contact the adhesive surface of the mica sheet, the resin powder being melted by the temperature from the heating roller while simultaneously bonding the mica assembly and said A method for manufacturing a laminated mica composite insulating material, characterized in that the insulating material is bonded to another insulating element. 10) In the manufacturing method according to claim 9,
A method for producing a laminated mica composite insulating material, characterized in that the other insulating element is a thin nonwoven fabric. 11) In the manufacturing method according to claim 9,
A method for producing a laminated mica composite insulating material, characterized in that the other insulating element is a laminated mica sheet. 12. In the manufacturing method according to claim 9,
The sprinkling process using the powder sprinkling means involves rotating a sprinkling roller whose surface is provided with fine irregularities in a powder tank, and adjusting the amount of resin powder adhering to the surface of the sprinkling roller to a specified amount using a doctor blade. and, after the adjustment step, an electrostatic dispersion step of pulling the resin powder attached to the dispersion roller downward using an electrostatic repulsion means and dispersing it. . 13) The manufacturing method according to claim 12, characterized by including a wiper step of mechanically scraping down the resin powder still adhering to the spreading roller after the electrostatic spreading step using a wiper blade. A method for manufacturing a laminated mica composite insulating material. 14) The manufacturing method according to claim 12 includes a wiper step for mechanically scraping off the resin powder adhering to the scattering roller with a wiper blade in a powder tank to prevent clogging. A method for producing a laminated mica composite insulating material comprising: 15) A method for producing a laminated mica composite insulating material according to claim '9, characterized in that the temperature of the heating roller is selected to be higher than the softening point of the resin by 10 to 50 degrees Celsius. .