KR20170033242A - Rectangular coil and a method of manufacturing the multi-layered structure coil coated by the modified PAI insulation varnishes with a high ceramic content - Google Patents

Abstract

The present invention relates to a rectangular coil coated with a modified PAI insulation varnish having a high ceramic content in a multi-layered structure and a method for manufacturing the same. The rectangular coil having a multi-layered structure according to the present invention comprises: a primer layer including modified polyamideimide; a main insulation layer formed on the surface of the primer layer and made of a mixture of modified polyamideimide having a relatively large number of amide groups or urethane groups and ceramic in a sol state; and a top coating layer formed on the surface of the main insulation layer and including polydimethylsiloxane-polyamideimide. According to the rectangular coil of the present invention, an insulation varnish forming each layer includes a high ceramic content. The rectangular coil of the present invention can satisfy characteristics such as adhesion, crack resistance, high thermal conductivity, high lubricity, abrasion resistance, and high insulation (withstanding voltage and discharge durability) even when bent/twisted.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectangular coil having a high-content ceramic and coated with a multilayer structure, and a method of manufacturing the varistor,

The present invention relates to a rectangular coil coated with a polyamideimide insulating varnish having a high content of ceramics and a method for producing the varnish. More particularly, the present invention relates to a polyolefin- A hybrid varnish for a primer in which a sol-state ceramic is added to a triblock-PAI copolymer introduced in the middle, an AA-PAI or a glycol having AA (adipic acid) incorporated therein so as to have a high flexibility and rigidity Hybrid varnish, which is made of modified polyunsaturated PUAI (polyurethanamideimide) with sol-state ceramic, Hybrid varnish for top coating with sol-state ceramic added to PDMS-PAI modified with silicone with low surface tension The varnish contains a high content of ceramics. Even when it is a rectangular coil, when it is warped / twisted, it shows adhesion, crack resistance, The present invention relates to a rectangular coil coated with a multilayer structure and an insulating varnish having a high content of ceramics capable of satisfying characteristics of high thermal conductivity, high lubricity, abrasion resistance and high insulation (withstanding voltage and discharge durability) and a manufacturing method thereof.

Since the use of electricity, energy efficiency, miniaturization, and improvement of long-term reliability of electric devices and parts have been constantly progressing. In order to achieve miniaturization and high efficiency, a prismatic conductor has become inevitable.

However, if the voltage applied to the conductor is square, the electric field is concentrated on the curved portion and the insulation reliability becomes a problem. Therefore, it is very difficult without developing a new material having extreme insulation durability. Recently, in the polymer varnish, a nano-scale colloid ceramic- The application of hybrid varnish materials has been attempted, but when a high amount of liquid colloidal ceramic is added to a high molecular weight resin, the adhesive strength to the metal is lowered, and cracks are generated during bending / twisting.

Generally, a rectangular conductor for a generator or a transformer is widely used with a radius of curvature of 0.5 mm or more, and most of them can be insulated by insulating varnish of a polymer resin alone.

Recently, motor coils having a cross sectional area of about 1 mm ² have been required to be square-shaped for miniaturization and high integration. At this time, the corner radius of the rectangular conductor should be 0.3 mm or less. When the radius of curvature becomes smaller, it is necessary to use a hybrid varnish in which the angles of curvature are sharp and the electric field is concentrated and ceramic is added in a high amount. When such an insulating varnish is bent by insulating ceramics insulating varnish, mechanical breakage There is a problem that it occurs easily.

Until recently, a number of patents have been filed on methods and techniques for improving the heat resistance, corona resistance and workability of enameled wires in connection with hybrid varnish insulation coils.

In the case of foreign technology, US GE Polyester and polyamide imide varnish dispersed nanoparticles to commercialize corona-inhibiting enamel wire. DuPont used inorganic filler to inhibit partial discharge of electric motor motors by 5% We have developed an enamel coil. In Japan, Hitachi Cable is developing high-efficiency motors capable of achieving maximum 72% reduction in peak voltage by developing various high-voltage hybrid insulated wires. Furukawa and Hitachi cables have recently developed an enamel wire that can suppress the corona of an inverter-driven motor based on nanocomposite technology. Sol-gel method has recently been introduced in the art for compounding inorganic nanoparticles, and the dissolution mixing method and the sludge coating method have been studied in Japan, the United States, and China, and many processes for favoring mass production have been developed.

In Korea, existing motor windings are single-layered or double enameled with a single resin such as polyurethane (PUE), polyester (PE), polyester imide (PEI) and polyamide imide It is produced and produced so that it can be selected accordingly. Recently, self-lubricated type windings suitable for high-temperature (200 ° C) in-line spheres for refrigeration or air-conditioner compressors have been developed. However, the technical approach to improve the motor load ratio is still insufficient, Has not yet been achieved.

PAI / PI insulation varnishes of the highest heat resistance class have been used for premium class high efficiency motors and highly integrated power devices. However, in advanced countries, in order to improve the performance of insulation varnishes, nanocomposite insulation varnish Has been developed and commercial utilization is being attempted.

The use of PDMS (polydimethylsiloxane), which has high surface energy and low surface energy, has been studied in coil top coatings, but its strength is low and its adhesion to other materials is low, making it difficult to use alone. Physical blending of hydrophobic PDMS, polarized polyimide, PA, and PAI results in phase separation on a macroscopic scale. However, when chemical substances with different surface energies are made into a single copolymer through covalent bonding, this phase separation can be effectively reduced.

On the other hand, a copolymer of silicon and organic molecules having a low surface energy and high flexibility has an advantage that a silicon portion can be easily exposed to a surface layer of a coating material even if a small amount is added, thereby obtaining a low surface tension.

On the other hand, in the case of miniaturization (increase in degree of integration) of electric devices and parts in which coils are embedded, efficiency deteriorates due to heat generation, deterioration of insulation performance due to thermal deterioration or discharge deterioration is a problem, and in order to improve the thermal conductivity of varnish, The use of insulating varnish is inevitable. Since the thermal conductivity of insulating varnish materials and the surge durability to high frequency power supply and inverter controller increase greatly as the content of ceramics increases, the commercial importance of adding high content ceramics is emphasized. However, cracks occur in flexure / Addition is very difficult.

Korean Patent Publication No. 10-2005-0070290, Jul.

SUMMARY OF THE INVENTION The present invention was made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a nano hybrid insulation varnish comprising a high-content ceramic in a denatured PAI on the surface of a rectangular conductor coated with a multilayer structure of a primer layer, / Modified PAI insulation varnish with a high content of ceramics that can satisfy the characteristics of adhesive force, crack resistance, high thermal conductivity, high lubricity, abrasion resistance and high insulation (withstanding voltage, discharge durability) And a method for producing the same.

According to an aspect of the present invention, there is provided a semiconductor device comprising: a metal conductor formed in a lengthwise direction; A primer layer formed on the surface of the metal conductor, the primer layer comprising a modified polyamideimide; Wherein the primer layer is formed on the surface of the primer layer, wherein the amorphous polyamide imide having a relatively large amide group or a urethane group is mixed with a ceramic in a sol state; And a top coating layer formed on the surface of the main refractory layer and including a polydimethylsiloxane-polyamideimide. The modified PAI insulation varnish having a high content of ceramics has a rectangular coil coated with a multilayer structure As a technical point.

Preferably, the modified polyamide imide of the primer layer is selected from the group consisting of oligo (oxyethylene glycol) (OEG), oligo (oxypropylene glycol) (OPG), BPA-oxyethylene glycol (BPA OEG) and adipic acid At least one of alcohols, cellosolves, and amines is formed on both ends of a modified triblock-polyamideimide (triblock-PAI) copolymer in which polyamideimide is synthesized at both ends, % Of the ceramic in the sol state.

The modified polyamide imide of the above-mentioned parenthesized soft layer may be an adipic acid-polyamideimide (AA-PAI) having adipic acid (AA) synthesized with polyamideimide (PAI) and having a relatively large amide group relative to the imide group, At least one of alcohols, cellosolves and amines is capped and formed at both ends of a urethane-modified polyamideimide (PUAI) into which 5 to 25 wt% of sol is mixed and formed do.

More preferably, the polydimethylsiloxane-polyamide imide of the top coating layer is a diblock copolymer (PAI-PDMS) or a triblock copolymer (PAI-PDMS-PAI), and the top coating layer contains 10 to 30 wt% Of ceramic.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a primer layer including a modified polyamideimide on a surface of a metal conductor formed in a long direction; A second step of forming a refractory layer in which a modified polyamideimide having a relatively large amide group or a urethane group on the surface of the primer layer is mixed with a ceramic in a sol state; And a third step of forming a top coating layer comprising a polydimethylsiloxane-polyamideimide on the surface of the pseudo-softening layer. The modified PAI insulating varnish having a high content of ceramic is coated with a multilayer structure A manufacturing method of a rectangular coil is described as a technical point.

Preferably, the modified polyamide imide in the first step is selected from the group consisting of oligo (oxyethylene glycol) (OEG), oligo (oxypropylene glycol) (OPG), BPA-oxyethylene glycol (BPA OEG) and adipic acid At least one of alcohols, cellosolves and amines is formed by capping at both ends of a modified triblock-polyamideimide (triblock-PAI) copolymer in which polyamideimide is synthesized at both ends with a center , The primer layer further includes a ceramic in a sol state, and the ceramic in the sol state is mixed in a range of 1 to 10 wt%.

The modified polyamide imide of the second stage may be an adipic acid-polyamideimide (AA-PAI) having a relatively large amide group relative to the imide group by synthesizing adipic acid (AA) with polyamideimide (PAI) The modified polyamide imide of the second step is formed by capping at least one of alcohols, cellosolves and amines at both ends of a urethane-modified polyamideimide (PUAI) into which glycols are introduced, The ceramic in the sol state of the pseudo-soft layer in the second step is added in an amount of 5 to 25 wt%.

More preferably, the polydimethylsiloxane-polyamide imide of the third step is a diblock copolymer (PAI-PDMS) or a triblock copolymer (PAI-PDMS-PAI) And the ceramic in the sol state is mixed in a range of 10 to 30 wt%.

According to the present invention, there is provided a rectangular coil coated with a modified PAI insulating varnish having a high content of ceramics according to the present invention and a method for producing the same, wherein the coil is modified to have a different chemical structure to form a primer layer, Each of the varnish materials containing a high content of nano-scale ceramics in the polymer is continuously coated on the rectangular conductor, so that the adhesive strength, crack resistance, high thermal conductivity, high lubricity, abrasion resistance and high insulation , And discharge durability).

Coils used in extreme environments or where insulation reliability is particularly required are required to improve the discharge durability and thermal conductivity of the insulating coating. The coil having a hybrid varnish with a high-content ceramic added to the rectangular conductor has a warpage / In addition to securing all the physical properties required in the insulating varnish upon deformation, it has an effect of excellent insulation reliability even in extreme environments.

In addition, by using PAI containing PAI-PDMS-PAI copolymer as an insulating material for the top coat layer, it is possible to facilitate the operation during winding by raising the lubricity, to make the winding in a small power well during the manufacture of the motor, Can be lowered.

Electric devices and parts made of such a rectangular coil can be miniaturized due to high integration degree, have excellent thermal diffusivity, increase energy efficiency, increase insulation durability, increase life span, and have a small economic maintenance effect .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram of cracking in the bending of a rectangular coil insulated by a high-content varnish of a ceramic in a sol state.
FIG. 2 is a comparative view of the crack generation magnitude due to the increase of the ceramic content in the polyamideimide and silica sol hybrid varnish coating film. FIG.
FIG. 3 is a developed product to which a continuous coating process of a rectangular coil is applied using a hybrid varnish according to a preferred embodiment of the present invention.
4 is a cross-sectional view of a motor slit applying a square coil according to a preferred embodiment of the present invention.
5 is a cross-sectional view of a triangular-layer rectangular coil insulated with a hybrid varnish according to a preferred embodiment of the present invention.
Fig. 6 shows the structure of a polyamide-imide resin according to a preferred embodiment of the present invention. Fig.
FIG. 7 is a synthesis and capping scheme of AA-PAI and PUAI according to a preferred embodiment of the present invention; FIG.
Figure 8 shows the structure of a silicone copolymer or capped polyamide amide of a hybrid varnish for top coating according to a preferred embodiment of the present invention.
Figure 9 is an actual view of a coil prototype made with a coating technique according to a preferred embodiment of the present invention;
FIG. 10 is a table of a coil specification test according to a preferred embodiment of the present invention. FIG.
11 is a comparison of bending characteristics of a conventional rectangular coil and a multi-layer rectangular coil according to a preferred embodiment of the present invention.
12 is a characteristic test graph of a conventional general PAI varnish.
13 is a characteristic test graph of polyamide-imide angular coils fabricated in a multilayer structure according to a preferred embodiment of the present invention.
14 is a chemical structure of BPA-OEG5 PAI triblock copolymer according to a preferred embodiment of the present invention.

Prior to describing the present invention, polyamideimide excellent in thermal durability, insulation performance (withstanding voltage characteristics, surge durability), adhesiveness, flexibility and toughness are mainly used as insulation varnish materials of N and C types, .

In order to increase the degree of integration of electric devices and components, it is becoming more compact and lighter. In order to increase the energy efficiency, the conductor is becoming quadrangular. In order to improve the surge durability and thermal conductivity of insulating material, it is inevitable to add nano ceramic.

However, when the organic / inorganic hybrid varnish with 5 wt% or more of the sol state ceramic is added to the rectangular conductor, it is possible to cause the separation between metal and varnish material during bending / twisting, Cracks will occur.

FIG. 1 is a conceptual diagram of cracking in the bending of a rectangular coil insulated by a high-content varnish of a ceramic in a sol state. Referring to FIG. 1, it can be seen that the occurrence of cracks during the warping of the square-shaped coil insulated by the varnish added with a high content of ceramic in the sol state is increased.

That is, strong stress occurs at the interface between the insulating coating layer coated on the outer surface and the copper surface. When the flexibility of the resin is insufficient, the interfacial bonding force between the silica and the resin is weak, or when the adhesion to the copper surface is weak, As shown in Fig.

Flexural deformation is inevitably generated in the manufacture of electric devices or parts by using a coil. The coating film on the outer side is subjected to stretching stress and the coating film on the inner side is subjected to compressive stress. As a result, as the content of the ceramic added to the insulating varnish coated on the surface of the copper conductor is increased, mechanical breakage occurs even under the same bending deformation, which makes it difficult to increase the ceramic content. This is because the addition of ceramics reduces the flexibility and elongation of the polymer film. It is found that when the shape of the conductor is angular, the mechanical stress to be applied when the conductor is deformed is larger than that of the annular shape, have.

2 is a comparative diagram of the crack occurrence size due to the increase of the ceramic content in the polyamideimide and silica sol hybrid varnish coating film. Referring to FIG. 2, it can be seen that cracking of the coating film is increased with increasing silica content in the polyamideimide and silica sol hybrid varnish.

That is, FIG. 2 is a schematic view of a 180 ° bending test. As shown in FIG. 2, a coated copper sheet is folded, a spacer having a predetermined thickness is placed therebetween, and sufficient stress is applied to cause a stress in the bent portion of the copper sheet to be.

Accordingly, after the test, the coating layer of the copper sheet is analyzed by image analysis to check the degree of cracking, thereby evaluating the adhesion of the coating layer to copper. As shown in FIG. 2, as the content of the silica nanoparticles increases, the coating layer becomes brittle and cracks are generated due to external stress. In the hybrid varnish, as the content of the ceramic in the sol state increases, It can be seen that this occurs largely.

Particularly, in case of a rectangular coil, the stress generated unlike the annular coil is concentrated near the angular portion, so that the destruction of the coating film is more serious. Therefore, in order to miniaturize and increase the viscosity, a square shape of the coil is required, and a nanohybrid varnish material in which a high content of silica nanoparticles are added is inevitable in order to improve the electrical and thermal properties. It is very important that the technology capable of solving the damage is very important.

FIG. 3 is a developed product to which a continuous coating process of a rectangular coil is applied using a hybrid varnish according to a preferred embodiment of the present invention. Referring to FIG. 3, a rectangular coil using a hybrid varnish developed according to the present invention can be continuously coated.

In other words, the optimum viscosity of the coating liquid and the structure control of the die are controlled so that the thickness deviation between the curved portion and the flat portion is minimized without eccentricity. This is a rectangular coil manufactured by coating the hybrid varnish for primer 2 to 4 times, the hybrid varnish for main spinning 10 to 14 times, and the hybrid varnish for top coating 1 to 2 times, and a separate varnish impregnated The three-layer structure can be continuously produced according to the arrangement of the bath.

4 is a cross-sectional view of a motor slit to which a square coil is applied according to a preferred embodiment of the present invention. Referring to FIG. 4, when the number of conductors of the same size is increased by increasing the degree of integration of the coils, the size of the slots is reduced to 10 to 15%.

In other words, if the number of conductors of the same size is the same, the size (weight, volume) of the electric device can be reduced by decreasing the size of the slot (10 to 15% . The number of coils that can be inserted into the same space depends on how much the coil is coiled in the manufacturing process. In addition, if the coefficient of friction of the surface is low, the coils can be wound tightly even when the same force is applied. High lubricity coating material is important.

In other words, when the coil is wound on the stator of the motor, the ratio of the conventional annular shape shown in the right side of FIG. 4 that can fill the space in the form of shape can be 60 to 70%. However, When the space is filled up, it is possible to stack up to 85%. As a result, the motor volume can be reduced by 7 ~ 10% and the efficiency can be improved by 10 ~ 15%.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the present invention are shown.

FIG. 5 is a cross-sectional view of a triple-layer rectangular coil insulated with a hybrid varnish according to a preferred embodiment of the present invention. As shown in FIG. 5, a square coil having a multilayer structure of insulating varnish having a high content of ceramics according to a preferred embodiment of the present invention includes a metal conductor 10, a primer layer 20, And a top coating layer 40.

The metal conductor 10 of the present invention is formed long in the longitudinal direction, and a single component or an alloy or the like may be formed long in the longitudinal direction.

As a matter of fact, any one of copper, aluminum and alloys thereof having excellent electrical conductivity and suitable for bending deformation may be selectively applied.

Such a metal conductor 10 can be formed into a square shape by stretching using a square type hardness die after producing a wire material by rolling.

The primer layer 20 of the present invention is a layer made of a hybrid varnish for a primer in which a modified polyamideimide and a ceramic in a sol state are mixed on the surface of the metal conductor 10, It can be said that the layer is coated.

The hybrid varnish for primer is a tri-block copolymer modified with oligo (oxyethylene glycol) (OEG), oligo (oxypropylene glycol) (OPG), BPA-oxyethylene glycol (BPA OEG) A varnish material in which a sol state ceramic is mixed with a polyamideimide (triblock-PAI) copolymer at a content of 1 to 10 wt% is applied.

At this time, the modified polyamide imide of the hybrid varnish for primer is composed of polyamide (polyamide) at both ends of the polyamide imide, centering on one of oligo (oxyethylene glycol) (OEG), oligo (oxypropylene glycol) (OPG), BPA-oxyethylene glycol (Triblock-PAI) copolymer. When the flexible chemical structure is contained in the polymer chain in a large amount, the thermal durability is lowered. Therefore, the molecular weight of the polyamideimide molecule is about 20,000 to 200,000 It is preferable to add the above-mentioned glycols to be a triblock-PAI copolymer structure.

The pseudo-softening layer (30) of the present invention is a layer composed of a hybrid varnish for punching which is formed by mixing a modified polyamideimide having a relatively large amide group on the surface of the primer layer (20) and a sol state ceramic.

Here, the modified polyamide imide having a relatively large number of amide groups or a urethane-containing adipic acid-polyamideimide (AA) having a relatively large amide group relative to the imide group is synthesized in the polyamideimide (PAI) -PAI) or at least one of alcohols, cellosolves, and amines is capped at both ends of the PUAI containing the glycol.

It is preferable that such a ceramics-based hybrid varnish contains 5 to 25 wt% of a ceramic in a sol state.

The top coating layer 40 of the present invention is a layer made of a hybrid coating for top coating in which polydimethylsiloxane-polyamideimide and sol-state ceramics are mixed in a concentration of 10 to 30 wt% on the surface of the main fusing layer 30, and polydimethylsiloxane - polyamide imide refers to a polydimethylsiloxane-polyamideimide copolymer. Such polydimethylsiloxane-polyamideimide copolymers include diblock copolymers (PAI-PDMS) and triblock copolymers (PAI-PDMS-PAI).

In order to develop a top coating material with high lubrication-self-adhesion property, a low surface energy polydimethylsiloxane (PDMS) can be copolymerized with polyamideimide by covalent bonding. When chemical substances with different surface energies are made into a single copolymer through covalent bonding, the phase separation can be effectively reduced. In addition, the triblock copolymer of PAI-PDMS-PAI among the copolymers has surface energy lowered by PDMS exposed on the surface, and is lubricated and can be self-fused because it does not exist alone.

Alumina, silica, boron nitride, or other electrically insulating ceramics may be used for the ceramics used in the sol of the present invention. That is, the sol-state ceramic in which the modified polyamide-imide and the amide group are relatively mixed with the modified polyamide-imide and the polydimethylsiloxane-polyamideimide, respectively, may be a ceramic selected from the group consisting of alumina, silica, boron nitride, .

Hereinafter, a method of manufacturing the above-described square coil in which the insulating varnish having a high content of ceramics is coated with a multilayer structure will be described in more detail.

Prior to this, the polyamide imide which is the basis of the insulating material coated on the primer layer 20, the fissure layer 30 and the top coating layer 40 of the present invention can be explained as follows.

6 shows the structure of a polyamide-imide resin according to a preferred embodiment of the present invention. The polyamide-imide resin, which is the base having the heat resistance grades N and C, has a chemical basic structure as shown in FIG. 6, and has excellent heat resistance and insulation. However, since the rigidity of the resin is high, It is preferable to chemically rejuvenate the polyamideimide molecules so as to meet the required functionality and enable the addition of a high content of ceramics to each material.

That is, the diisocyanate compound and the acid anhydride compound are reacted at a predetermined stoichiometric ratio to synthesize polyamideimide having a certain amount of isocyan (-NCO) group at the terminal.

For reference, the diisocyanate compound is 4,4'-methylenebis (phenyl isocyanate), 2,4-methylenebis (phenyl isocyanate) )) And derivatives thereof may be selectively used. And the acid anhydride compound may optionally use one or more of TMA (trimellitic anhydride) and its derivatives.

These triblock-PAI copolymers are used for primer insulators using polyimide imide as the base resin. Capped AA-PAI and PUAI are used for the main flame retardant, and PDMS-PAI is used for the top coating insulation. It is preferable to hybridize the silane-treated sol state ceramic by synthesizing a special resin, and although it is an insulating varnish containing a high content (10 to 25 wt%) of ceramic in a sol state, , It is not difficult to manufacture a rectangular coil coated with a topcoat insulating material, and it can satisfy various physical properties required in a coil.

First, in the first step, a primer layer 20 is formed of a hybrid varnish for a primer in which a modified polyamideimide and a sol-state ceramic are mixed on a surface of a metal conductor 10 formed in a lengthwise direction.

In the first step, a hybrid varnish for a primer is coated on the surface of the metal conductor 10, and a hybrid varnish for a primer is coated with oligo (oxyethylene glycol) (OEG), oligo (oxypropylene glycol) PAI copolymer modified with OPG, BPA-oxyethylene glycol (BPA OEG), AA or the like is added in an amount of 1 ~ 10 wt%.

When such a flexible chemical structure is contained in the polymer chain, the thermal durability is lowered. Therefore, the glycol is added to the triblock-PAI copolymer structure while the polyamideimide molecules are being polymerized at a molecular weight of 20,000 to 200,000.

At this time, the primer layer 20 formed on the metal interface, which should have excellent flexibility and adhesion, is poor in flexibility and adhesiveness when a high content of ceramics is prescribed. Therefore, colloidal silica sol is preferably added in a range of 1 to 10 wt%. If the sol state ceramic is less than 1 wt%, the effect of improving the thermal characteristics and the electrical characteristics is small, and if it exceeds 10 wt%, the flexibility and adhesiveness may be weak.

Next, the second step is to form a pseudo-soft layer 30 comprising a primer layer 20 having a relatively large amount of amide groups or a modified polyamide-imide containing urethane groups and a sol-state ceramic .

The main fracture layer 30 formed in the second step is coated with a thick film on the surface of the primer layer 20 so as to have discharge durability (surge durability) in addition to basic insulation and mechanical rigidity. Therefore, these limitations can be overcome by combining high contents of nano-level ceramics.

Molecular manipulation of the polymer is necessary to prevent mechanical breakage which is a problem when a high content of ceramic is added through the increase of flexibility of the resin of the core layer (30) and the strengthening of the interfacial bonding force between silica and resin in the core layer (30).

Improvement of resin flexibility by controlling molecular weight and chemical structure of polyamide-imide resin (30) and improvement of crack resistance against external stress by strengthening interfacial bonding strength between silica and resin through surface treatment of silica nanoparticles are required .

In order to prevent adhesiveness and flexibility degradation in high solubility ceramics in the hybrid varnish, it is necessary to add some adipic acid (AA) and glycols in place of TMA to properly control the stiffness and flexibility of the polyamideimide chain, If the terminal structure of the amideimide resin is capped with various materials contributing to dispersion stabilization of the ceramic in the sol state, properties of the varnish insulating material can be secured even with a high content of ceramics.

7 is a synthesis and capping scheme of AA-PAI and PUAI according to a preferred embodiment of the present invention. Referring to FIG. 7, after the synthesis of AA-PAI or urethane-containing PUAI having a large number of amide groups relative to the imide group as a resin for the main mortar layer 30, at least one of alcohols, cellosolves, Respectively.

When the resin modified by the modification of the main chain of the polymer and the capping of the polymer terminal is used as the resin of the main burning hybrid varnish, even if the surface-modified ceramic modified with various silanes is added in the amount of 5 ~ 25wt%, the hybrid varnish insulation It is possible to satisfy the physical property as material. If the sol state is less than 5 wt%, the physical properties of the hybrid varnish insulating material can not be satisfied. If it exceeds 25 wt%, the physical properties may deteriorate.

For the polyamideimide (including polyamideimide for primer) of the hybrid varnish, it is necessary to cap the polymer terminal to improve the dispersion stability, flexibility and adhesion of the sol state ceramic. As the capping agent suitable for the polyamideimide resin, Solvates and 12-amines.

Finally, the third step is a step of forming a top coating layer 40 made of hybrid varnish for top coating in which polydimethylsiloxane-polyamideimide and sol-state ceramics are mixed on the surface of the main fracture layer 30.

The top coating layer 40 in the third step is a layer formed by coating a hybrid coating for top coating in which polydimethylsiloxane-polyamideimide and sol-state ceramics are mixed on the surface of the mortar layer 30, and polydimethylsiloxane -Polyamide imide preferably comprises a diblock copolymer (PAI-PDMS), a triblock copolymer (PAI-PDMS-PAI).

That is, the hybrid varnish for top coating can be used by synthesizing a polydimethylsiloxane-polyamideimide copolymer having a low surface tension. Such a silicone copolymer may be used in which polydimethylsiloxane is contained therein for self-bonding.

FIG. 8 is a structure of a silicone-capped polyamide amide of a hybrid coating for top coating according to a preferred embodiment of the present invention. Referring to FIG. 8, it can be seen that the use of the resin capped in the polyamideimide terminal is effective for high lubricity.

As a result, it is possible to use hybrid polystyrene as a hybrid for top coating by mixing ceramic particles with polydimethylsiloxane-polyamideimide copolymer synthesized by using polyamide-imide resin-capped terminal. Do. However, the micro / nano composite material which can be used as the hybrid coating for the top coating may include nano-micro composite and nano hybrid material.

The hybrid varnish for top coating which forms the outermost surface layer of the rectangular coil has lubricity and can work in the production of the applied product and can be wound at high tension without mechanical damage of the insulating film, .

In addition, boron nitride (BN) has a solid lubrication due to its well-developed layered structure. It has excellent insulation characteristic due to its plate shape and high thermal conductivity, so it can rapidly dissipate heat generated during operation of power equipment, to be.

The hybrid varnish for top coating prepared by using BN (boron nitride) nano sol in addition to silica and alumina in the silicon-capped polyamideimide of FIG. 8 is capable of imparting high lubricity and has an effect of enhancing thermal conductivity when used as a top coating agent .

Particularly, it is preferable that the coating composition is a high-lubrication top coat which is hybridized with a ceramic content of 10 to 30 wt% in a sol state. At this time, when the ceramics in the sol state is less than 10 wt%, the thermal conductivity or the insulating property is low, and when it exceeds 30 wt%, the adhesion property of the hybrid varnish for top coating is deteriorated. Thus, even when the ceramic content is 10 wt% or more as a whole, it is possible to produce a rectangular coil having lubricity while satisfying physical properties as a coil insulating material.

In order to enhance the silica / resin interface strength, it is preferable to modify the surface of the ceramic in a sol state with silane. That is, when the ceramic surface is appropriately surface-treated with an organosilane having reactive groups such as amine, thiol, epoxide and carboxylic acid, physicochemical bonding is effectively formed at the organic / inorganic interface. In some cases, an additional oligomer amide- A method of inducing mechanical coupling is also used.

Therefore, the insulating material of the present invention contains a high content of ceramics and is coated on the fine square metal conductor 10 to satisfy the mechanical and electrical characteristics. In this case, both of the primer insulating material, It is possible to manufacture a square coil that is insulated with a hierarchical triple structure by using insulating varnishes that are modified chemically and functionally to hybridize the ceramics with a high content of ceramics, which will have commercial significance.

A prototype of a PAI resin / silica sol hybrid varnish insulated square coil will be described.

FIG. 9 is an actual view of a test piece for evaluating electrical characteristics of a coil prototype fabricated by a coating technique according to a preferred embodiment of the present invention. Referring to FIG. 9, it can be seen that electrical characteristics are maintained even when a product having a significantly large winding strain is manufactured using a PAI resin / silica sol hybrid varnish insulated square coil.

10 is a table of a coil specification test according to a preferred embodiment of the present invention. Referring to FIG. 10, it can be seen that a coil type test (IEC 60317-58) is applied to a coil prototype manufactured by the high-content ceramic hybrid multilayer coating technique shown in FIG.

In other words, a hybrid of various compositions is possible. In FIG. 10, a prismatic layer (5 wt% of ceramics) of the sample A, a prismatic layer of the sample B (15 wt% of the ceramics) and a top coat layer of the sample C Mechanical properties such as adhesion to the coil, film scratch resistance, and electrical characteristics such as pinholes and breakdown voltage all exhibited excellent characteristics above the reference value.

11 is a curvature comparison chart of a conventional rectangular coil and a multi-layer rectangular coil according to a preferred embodiment of the present invention. Referring to FIG. 11, it can be seen that the flexural characteristics of a general polyamideimide varnish square coil and the hybrid square coil of the multilayer structure of the present invention are compared with each other.

That is, as can be seen from FIG. 11, when the change of the coil end at 180 ° is examined, it can be seen that cracks are generated in the conventional polyamideimide varnish, while cracks are not generated in the end portions of the rectangular coil coated with the multilayer structure have. This can be seen as a result of a good fusion of the effect of the primer layer which enhances the adhesion with the copper conductor and the adhesion of the core layer.

12 is a characteristic test graph of a conventional general PAI varnish. Referring to FIGS. 12A and 12B, it can be seen that the insulation characteristics and the partial discharge characteristics of the conventional PAI varnish insulated round and rectangular coils are tested.

Specifically, FIG. 12 shows changes in the electrical characteristics of the coils while changing the tension to 2, 5, and 10 kfg in winding the annular and rectangular coils of the copper conductor coated with the conventional general PAI varnish on the motor stator. As described above, when both the annular and square type coils of the general PAI varnish are pulled and pulled with a tension of 3 kgf or more, the insulation resistance and partial discharge characteristics are reduced by 20 to 30%.

In addition, the angular shape shows a larger deterioration width due to the greater damage to the tension on the structure having the curved edges. As shown in FIG. 12, when the coil is pulled with a large force, a pinhole is formed due to the development of a small crack in the material of the coating layer, and electrical insulation and partial discharge characteristics are deteriorated.

13 is a characteristic test graph of a polyamide-imide square coil manufactured in a multilayer structure according to a preferred embodiment of the present invention. Referring to FIG. 13, it can be seen that the insulation resistance characteristic test of the hybrid varnish insulated square coil is shown.

This is a result of testing the insulation resistance and partial discharge characteristics of the coil with respect to the same tension change for polyamide-imide square type coils fabricated in a multilayer structure to solve the problem of FIG. As can be seen from Fig. 13, the insulation resistance is hardly reduced at a tension of up to 3 kfg as compared with a single polyamide-imide resin coil, and even when working at a tension of 5 kgf, Which indicates that the insulating property is insufficient.

Hereinafter, an embodiment related to a square coil in which an insulating varnish having a high content of ceramics is coated with a multilayer structure and a method for manufacturing the same will be described.

For primer BPA - oxyethylene  glycol-modified PAI ( BPA OEG5 - PAI ) synthesis

14 is a chemical structure of BPA-OEG5 PAI triblock copolymer according to a preferred embodiment of the present invention. Referring to FIG. 14, it can be seen that a modified polyamideimide for preparing a hybrid varnish for a primer is prepared.

55.0 g of NMP as a solvent is added to the reaction flask, and 0.101 mol (19.5 g) of trimellitic anhydride (TMA) and 0.1 mol (25 g) of 4,4'-methylenebis (phenylisocyanate .

Thereafter, the temperature of the reaction flask was raised to 70 캜 and the polymerization reaction was carried out for 3 hours. When the viscosity reached 4 poise, 0.5 mmol (3.34 g) of OEG (n = 5) -BPA was diluted in 5 g of NMP and continuously reacted. 2 g of PGME in 10 poise was diluted in 10 g of NMP And the polymer terminal was cooled while being capped.

Thus, a solid content of 35 wt% BPA-OEG5-PAI was synthesized and used for hybridization with silica sol. The weight average molecular weight was about 60,000 and the hybrid with 10 wt% of silica sol was well used as a hybrid insulation material for the primer layer of the coil.

Main course  Capped Amide-rich PAI  synthesis

55 g of NMP as a solvent was added to the reaction flask and 0.081 mol (15.6 g) of TMA, 0.02 mol (2.9 g) of AA and 0.1 mol (25 g) of 4,4'-methylenebis And dissolved by stirring.

Thereafter, the temperature of the reaction flask was raised to 80 ° C., reacted for 3 hours, heated to 120 ° C. and continuously reacted. When the viscosity reached 10 poise, 2 g of 1-methoxy-2-propanol (PGME) was diluted in 10 g of NMP, The polymer terminals were cooled while capping.

Thus, 35 wt% AA-PAI was synthesized and used for hybridization with silica sol. The weight average molecular weight was about 70,000, and the hybrid with 30wt% of silica sol was well used and used as a hybrid insulation material for the core of the coil. Referring to FIG. 7, it can be seen that AA is added to synthesize AA-PAI.

For top coating Polydimethylsiloxane - polyamideimide type copolymer (A-B diblock  copolymer

A solution of 3.67 g of PGME in 48.17 g of NMP is prepared and the solution is added to 200 g of PAI of 60,000 to 70,000 Da having a solid content of 34%. The PGME and PAI solution are heated to 80 ° C. and maintained for 2 hours.

Thereafter, the temperature is lowered to room temperature, and diamine-PDMS (Tegomer A-Si 2322, ~ 2600 g / mol) is added at a solid content ratio of 0.5 to 30% and stirred at 200 rpm for 2 hours or more.

When PAI capped with PGME without immediately reacting diamine-PDMS is kept at room temperature for more than one week, the remaining PGME reacts with all isocyan (-NCO) groups of PAI to react with polydimethylsiloxane (PDMS) Can not.

As described above, according to the present invention, each of the varnish materials modified to different chemical structures and containing a high content of nano-scale ceramics in the polymer of the primer layer, the pearl layer and the top coating layer is continuously coated on the rectangular conductor, / It is possible to satisfy the characteristics of adhesion, crack resistance, high thermal conductivity, high lubricity, abrasion resistance and high insulation (withstanding voltage and discharge durability) even when deformed by twisting.

In other words, by manufacturing a coil to which a high-content ceramic is added to a rectangular conductor, it is expected that insulation reliability in the extreme environment is expected to be excellent in addition to securing all the physical properties required in the insulating varnish during warping / coiling.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention may be embodied otherwise without departing from the spirit and scope of the invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to illustrate them, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of the claims should be construed as being included in the scope of the present invention.

10: metal conductor
20: Primer layer
30:
40: Top coating layer

Claims (18)

A metal conductor formed to be long in the longitudinal direction;
A primer layer formed on the surface of the metal conductor and comprising a modified polyamideimide;
Wherein the primer layer is formed on the surface of the primer layer, the primer layer having a relatively large amide group or a modified polyamideimide containing a urethane group and a ceramic in a sol state; And
And a top coating layer formed on the surface of the main refractory layer and including a polydimethylsiloxane-polyamideimide. The polyimide siloxane-varnish coating varnish according to claim 1, wherein the modified PAI insulating varnish has a high content of ceramics. The method according to claim 1,
In the modified polyamide imide of the primer layer,
a modified triblock block in which polyamideimide was synthesized at both ends of one of oligo (oxyethylene glycol) (OEG), oligo (oxypropylene glycol) (OPG), BPA-oxyethylene glycol (BPA OEG) and adipic acid Characterized in that at least one of alcohols, cellosolves and amines is capped at both ends of a polyamide-imide (triblock-PAI) copolymer and the modified PAI insulating varnish having a high content of ceramics is formed into a multilayer structure Coated square coil. The method according to claim 1,
The primer layer,
1 to 10 wt% of a ceramic in a sol state is further included. The rectangular PAI insulating varnish having a high ceramic content is coated with a multilayer structure. The method according to claim 1,
The modified polyamide imide of the above-
Characterized in that adipic acid (AA) is synthesized in polyamideimide (PAI) and is adipic acid-polyamideimide (AA-PAI) having a relatively large amide group relative to imide group. A rectangular coil with varnish coated in a multilayer structure. The method according to claim 1,
The modified polyamide imide of the above-
Characterized in that at least one of alcohols, cellosolves, and amines is capped at both ends of a urethane-modified polyamideimide (PUAI) into which glycols have been introduced, characterized in that a modified PAI insulating varnish A rectangular coil coated with a multilayer structure. The method according to claim 1,
The ceramic in a sol state of the above-
And 5 to 25 wt% of the total weight of the ceramic varnish, wherein the modified PAI insulating varnish having a high content of ceramic is coated with a multilayer structure. The method according to claim 1,
The polydimethylsiloxane-polyamide-imide of the top coating layer can be obtained by,
Wherein the modified PAI insulating varnish has a high content of ceramic and is coated with a multilayer structure, characterized in that it is a diblock copolymer (PAI-PDMS) or a triblock copolymer (PAI-PDMS-PAI). The method according to claim 1,
The top coating layer,
Wherein the ceramic varnish further comprises 10 to 30 wt% of a ceramic in a sol state, wherein the modified PAI insulating varnish is coated with a multilayer structure. The method according to any one of claims 1, 3, 6, and 8,
In the ceramic state in the sol state,
Characterized in that the ceramic varnish comprises a ceramic selected from the group consisting of alumina, silica, boron nitride and mixtures thereof. A first step of forming a primer layer including a modified polyamideimide on the surface of a metal conductor formed in a long direction;
A second step of forming a refractory layer in which a modified polyamideimide having a relatively large amide group or a urethane group on the surface of the primer layer is mixed with a ceramic in a sol state; And
And a third step of forming a top coat layer comprising a polydimethylsiloxane-polyamideimide on the surface of the main fracture layer. The modified PAI insulating varnish having a high content of ceramics has a square shape A method of manufacturing a coil. 11. The method of claim 10,
In the modified polyamide imide in the first step,
a modified triblock block in which polyamideimide was synthesized at both ends of one of oligo (oxyethylene glycol) (OEG), oligo (oxypropylene glycol) (OPG), BPA-oxyethylene glycol (BPA OEG) and adipic acid Characterized in that at least one of alcohols, cellosolves and amines is capped at both ends of a polyamide-imide (triblock-PAI) copolymer and the modified PAI insulating varnish having a high content of ceramics is formed into a multilayer structure A method for manufacturing a coated rectangular coil. 11. The method of claim 10,
The primer layer in the first step is,
A ceramic in a sol state is further included,
Wherein the ceramic is mixed in a range of 1 to 10 wt%, and the modified PAI insulating varnish having a high ceramic content is coated in a multilayer structure. 11. The method of claim 10,
The modified polyamide imide of the second step is a modified polyamide imide,
Characterized in that adipic acid (AA) is synthesized in polyamideimide (PAI) and is adipic acid-polyamideimide (AA-PAI) having a relatively large amide group relative to imide group. Wherein the varnish is coated in a multilayer structure. 11. The method of claim 10,
The modified polyamide imide of the second step is a modified polyamide imide,
Characterized in that at least one of alcohols, cellosolves, and amines is capped at both ends of a urethane-modified polyamideimide (PUAI) into which glycols have been introduced, characterized in that a modified PAI insulating varnish Wherein the coil is coated with a multilayer structure. 11. The method of claim 10,
Wherein the ceramic in a sol state contained in the pseudo-soft layer of the second step comprises
And 5 to 25 wt% of the modified PAI insulating varnish having a high content of ceramic is coated with a multilayer structure. 11. The method of claim 10,
The polydimethylsiloxane-polyamideimide of the third step is a polyimide-
(PAI-PDMS) or triblock copolymer (PAI-PDMS-PAI), characterized in that the modified PAI insulation varnish is coated with a multilayer structure. 11. The method of claim 10,
Wherein the top coating layer of the third step comprises
A ceramic in a sol state is further included,
Wherein the ceramic is mixed in a range of 10 to 30 wt%, and the dense PAI insulating varnish having a high ceramic content is coated with a multilayer structure. 18. A method according to any one of claims 10, 12, 15 and 17,
In the ceramic state in the sol state,
Wherein the modified PAI insulating varnish comprises a ceramic selected from the group consisting of alumina, silica, boron nitride, and mixtures thereof.

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