JP2017169394A - Insulation paper for rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide insulation paper for rotary electric machine excellent in heat resistance and electric insulation properties while reducing a used amount of aromatic polyamide paper.SOLUTION: There is provided insulation paper 40 for rotary electric machine which is used in a rotary electric machine having a core 10 having a plurality of slot grooves and a plurality of coils 20 stored in the slot grooves, is stored in the slot grooves together with the coils, and is used for securing insulation properties between the coils or between the coil and the core, where the insulation paper for rotary electric machine has such a laminated structure that resin sheets are laminated on both surfaces of a base material sheet, the base material sheet is aromatic polyamide paper, and in the resin sheet, a first resin sheet laminated on one surface side of the base material sheet is a polyester film and a second resin sheet laminated on the other surface side of the base material sheet is polyester fiber non-woven fabric.SELECTED DRAWING: Figure 1

Description

  The present invention relates to insulating paper for rotating electrical machines.

  Conventionally, insulation paper in which an aromatic polyamide paper called “aramid paper” is laminated on both sides of a polyester film made of polyethylene naphthalate or polyethylene terephthalate, etc., has heat resistance, electrical insulation, mechanical strength, and surface slippage. It is widely used as insulating paper for rotating electrical machines such as motors and generators (see Patent Document 1 below).

JP 2008-178197 A

  In recent years, rotating electric machines have been used for drive sources for hybrid vehicles and electric vehicles, and are required to be smaller and have higher output. For this reason, rotating electrical machines are required to improve the coil space factor in the stator core. Therefore, the insulating paper for rotating electrical machines is required to be thin while having the same level of electrical insulation and heat resistance as conventional.

Considering the electrical insulation of the insulating paper for rotating electrical machines, it is difficult to make the polyester film extremely thin.
Of the members constituting insulating paper for rotating electrical machines, aromatic polyamide paper is effective for exhibiting excellent slipperiness with respect to the stator core and the like, but is more expensive than general polymer nonwoven fabrics. Therefore, considering the cost of insulating paper for rotating electrical machines, it is desirable to reduce the amount used.

  For this reason, it is considered effective to reduce the thickness of the aromatic polyamide paper in order to satisfy the above demand. However, it is difficult to reduce the thickness of aromatic polyamide paper due to the manufacturing method, and a sufficiently thinned aromatic paper is not provided to the market.

  Of both surfaces of the insulating paper for rotating electrical machines, the side in contact with the coil does not require higher slipperiness than the side in contact with the stator core or the like. Therefore, unlike the conventional insulation paper for rotating electrical machines, aromatic polyamide paper is not laminated on both sides of the polyester film, but aromatic polyamide paper is laminated only on one side of the polyester film to reduce the thickness of the insulation paper for rotating electrical machines. Can be considered.

As a result of intensive studies by the present inventor on this point, when the configuration in which the aromatic polyamide paper is simply removed from one side of the conventional insulating paper for rotating electrical machines is adopted, the insulating paper for rotating electrical machines is sufficiently good at high temperatures. It has been found that the problem of not exhibiting good electrical insulation occurs. Therefore, the present invention has an object to solve such a problem.
That is, an object of the present invention is to provide an insulating paper for rotating electrical machines that is excellent in heat resistance and electrical insulation while reducing the amount of aromatic polyamide paper used.

  As a result of intensive studies by the present inventors, it has been found that the difference in thermal shrinkage between the aromatic polyamide paper and the polyester film is a factor causing the above problems. And this inventor employ | adopts the special structure of bonding a polyester fiber nonwoven fabric to an aromatic polyamide paper on the opposite side to the side by which the polyester film is bonded together, and bonding another fiber sheet on a fiber sheet. As a result, the inventors have found that the above problem can be solved, and have completed the present invention.

  That is, in order to solve the above problems, the present invention is used in a rotating electrical machine having a core having a plurality of slot grooves and a plurality of coils housed in the slot grooves, and is housed in the slot grooves together with the coils. An insulating paper for rotating electrical machines used to ensure insulation between coils or between a coil and a core, and has a laminated structure in which resin sheets are laminated on both surfaces of a base sheet, and the base sheet is The first resin sheet laminated on one side of the base sheet is a polyester film and is laminated on the other side of the base sheet. An insulating paper for rotating electrical machines in which the resin sheet of No. 2 is a polyester fiber nonwoven fabric is provided.

  According to the present invention, it is possible to provide an insulating paper for rotating electrical machines that is excellent in heat resistance and electrical insulation even when only one aromatic polyamide paper is used as a constituent member.

The schematic perspective view of the stator of the drive motor of HEV or EV. The schematic plan view of a stator core. The A section enlarged view of FIG. 1 is a schematic cross-sectional view showing a cross-sectional structure of a slot liner according to an embodiment. The figure (graph) which showed the heat shrink test result at high temperature. The figure (graph) which showed the heat shrink test result at high temperature.

Embodiments of the present invention will be described with reference to the drawings.
Here, the rotating electrical machine is a drive motor for a hybrid vehicle (HEV), an electric vehicle (EV), etc., and the insulating paper for rotating electrical machines (hereinafter also simply referred to as “insulating paper”) of the present invention is a slot liner. An example will be described.
More specifically, here, the drive motor includes an annular stator provided with a coil, and a rotor disposed inside the stator, and the stator includes a coil formed by a segment conductor (Segment Conductor). The embodiment of the present invention will be described by taking the case where it is provided as an example.

FIG. 1 is a perspective view of a stator 1 of a drive motor according to the present embodiment. As shown in the figure, the stator has a stator core 10 and a coil 20.
The drive motor according to the present embodiment includes a core having a plurality of slot grooves and a plurality of coils accommodated in the slot grooves.
The insulating paper of this embodiment is accommodated in the slot groove together with the coil and used to ensure insulation between the coils or between the coil and the core.
The insulating paper of this embodiment is used as a slot liner for insulation between the coil and the core in the stator.

  FIG. 2 is a plan view of the stator 1 as seen from the direction of the rotation axis (arrow AD) of the rotor (not shown). FIG. 3 shows a plurality of coils 20 in the portion A of the stator core 10 shown in FIG. It is sectional drawing which showed a mode that it accommodated.

As shown in these drawings, the stator 1 has a plurality of slot grooves 11 formed on the inner peripheral surface side of a cylindrical stator core 10.
The stator 1 includes the stator core 10 and a plurality of coils 20 accommodated in slot grooves 11 formed in the stator core 10.
The plurality of slot grooves 11 are arranged in the stator core 10 in a state where the individual slot grooves extend along the rotation axis direction AD and are spaced apart from each other in the circumferential direction (arrow RD) of the stator core 10. Has been.
The slot groove 11 is formed over the entire length of the stator core 10 in the rotation axis direction AD, and includes one end face 10a (upper side in FIG. 1, hereinafter also referred to as “upper end face 10a”) and the other end face 10b (hereinafter referred to as “upper axis direction”). An opening 11b having the same shape as the cross-sectional shape of the slot groove 11 is formed in the “lower end surface 10b”.

Since the stator core 10 has a plurality of slot grooves 11 in parallel as described above, a plate-like protrusion is formed between adjacent slot grooves.
A plurality of the plate-like protrusions 12 (hereinafter also referred to as “teeth 12”) are formed in a state of protruding toward the inner side in the radial direction (arrow DD) of the stator core 10.
In addition, the said teeth 12 have the wide part 12a which spreads in the circumferential direction RD of the stator core 10 in the protrusion direction front-end | tip part, and cross-sectional shape is a T-shape.
Therefore, on the inner peripheral surface side of the stator core 10, the width of the slot groove 11 is narrowed to form a slightly linear opening 11 a.

The coil 20 is composed of a plurality of segment conductors 21 connected to each other.
The segment conductor 21 ′ before the coil formation is a flat enameled wire bent into a U shape, and includes two leg portions 21b and a head portion 21a ′ connecting the leg portions 21b ′. It is a thing.
The segment conductor 21 ′ in the present embodiment has a copper wire exposed portion from which the insulating coating is peeled off at the tip portion 21bx ′ of the leg portion 21b ′ opposite to the head side.
In the coil 20 in this embodiment, the leg portion 21 b ′ of the segment conductor 21 ′ is inserted from the opening 11 b of the slot groove in the upper end surface 10 a of the stator core 10, and the tip portion 21 bx ′ is connected to the lower end surface of the stator core 10. After protruding from 10b, the leg portion 21b 'of one segment conductor 21' and the leg portion 21b 'of another segment conductor 21' are electrically connected at the conductor exposed portion, and an insulation treatment is further applied to this connection portion. It was made by applying.
Therefore, the stator 1 in the present embodiment has a coil end portion formed by the head portion 21a ′ of the segment conductor 21 ′ on the upper end surface side of the stator core 10, and the leg portions are connected to the lower end surface side. It has a coil end part constituted by the connection part 21x.

Four leg portions 21b of the segment conductors 21 forming the coils 20 are accommodated in the slot grooves 11 of the stator core 10, respectively, and each slot groove 11 is aligned in a row outward from the inside. In total, four legs 21b are accommodated.
The slot liner 40, which is insulating paper for rotating electrical machines in the present embodiment, is interposed between the four leg portions 21b and the inner wall surface of the slot groove 11.
The slot liner 40 is arranged in the slot groove so as to bundle the four leg portions 21b together.
More specifically, the slot liner 40 is vertically attached along the longitudinal direction of the leg portion 21b of the segment conductor 21, and is disposed in the slot groove so as to circulate around the four leg portions 21b more than once. Both end portions in the rotational axis direction AX are arranged in the slot groove so as to protrude outward in the rotational axis direction from the upper end surface 10a and the lower end surface 10b of the stator core 10.

Since the slot liner 40 is arranged in the slot groove so as to circulate around the four leg portions 21b at least once as described above, the slot liner 40 has a shape in which both end portions in the circumferential direction are overlapped. It is arranged in the groove.
That is, in the stator 1 of the present embodiment, the overlapping portion 40a where the slot liners 40 overlap each other is formed in the slot groove.
And the stator 1 of this embodiment has located the overlapping part 40a where this slot liner 40 overlapped on the radial direction outer side.

As shown in FIG. 4, the slot liner 40 in the present embodiment is a sheet body having a laminated structure, in which resin sheets 43 and 44 are laminated on both surfaces of a base sheet 41 via an adhesive layer 42.
In the present embodiment, the base sheet 41 of the slot liner 40 is an aromatic polyamide paper.
The 1st resin sheet 43 laminated | stacked on the one surface side of the said base material sheet among the said resin sheets 43 and 44 is a polyester film.
The 2nd resin sheet 44 laminated | stacked on the other surface side of the said base material sheet 41 is a polyester fiber nonwoven fabric.

Examples of the aromatic polyamide paper used for the base sheet 41 include a sheet obtained by dispersing wet fibers made of wholly aromatic polyamides and synthetic pulp made of wholly aromatic polyamides in water to make paper, and short fibers and synthetic pulps. In addition, a sheet obtained by mixing mica powder (mica flakes) and a sheet obtained by calendering these sheets at a high temperature and a high pressure can be used.
Examples of the wholly aromatic polyamide constituting the short fiber or the synthetic pulp include a polycondensation product of m-phenylenediamine and isophthalic acid and a polycondensation product of p-phenylenediamine and terephthalic acid.

The aromatic polyamide paper functions to prevent the buckling from occurring when the slot liner 40 is inserted into the slot groove 11 by giving the slot liner 40 an appropriate stiffness.
In this respect, the aromatic polyamide paper is preferably thicker.
On the other hand, when the space factor of the coil is taken into consideration, the aromatic polyamide paper is preferably thinner. Therefore, the aromatic polyamide paper preferably has a thickness of 25 μm to 200 μm. The thickness of the aromatic polyamide paper can be determined by a micrometer or the like, and the thickness of the aromatic polyamide paper is an average value obtained by arithmetically averaging the measurement results at a plurality of locations (for example, 10 locations) on the micrometer. Can be sought.

The polyester film used for the first resin sheet 43 is effective for making the slot liner 40 exhibit excellent electrical insulation.
In this respect, the polyester film is preferably thicker.
On the other hand, when the space factor of the coil is taken into consideration, the polyester film is preferably thin. Therefore, the polyester film preferably has a thickness of 5 μm to 200 μm. The thickness of the polyester film can be obtained in the same manner as the thickness of the aromatic polyamide paper.

In addition, as polyester-type resin which comprises a polyester film, for example, dicarboxylic acid, such as terephthalic acid and 2, 6-naphthalenedicarboxylic acid, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1, Examples thereof include diols such as 4-cyclohexanedimethanol as main structural units.
Specifically, examples of the polyester resin include polyethylene terephthalate resin (PET), polytrimethylene terephthalate resin (PTT), polybutylene terephthalate resin (PBT), polyethylene naphthalate resin (PEN), and polybutylene naphthalate. Resin (PBN) etc. are mentioned.

The polyester-type resin which comprises a polyester film does not need to be 1 type individually, and 2 or more types may be used together.
The polyester film may be a laminate film in which a plurality of polyester films thinner than the polyester film are laminated.

When the polyester resin has crystallinity, the melting point measured by the DSC method is usually 200 ° C. or higher and has high heat resistance.
In addition, the polyester resins as described above are often amorphous and have a softening point of 200 ° C. or higher, and exhibit high heat resistance.

The slot liner 40 of the present embodiment includes such a polyester resin film as a constituent member.
For this reason, the slot liner 40 of the present embodiment exhibits excellent insulating properties even at high temperatures.

In addition, it is preferable that the said 1st resin sheet 43 is a PET film, a PBT film, a PEN film etc. in what was illustrated above.
In particular, since various types of PET films having different thicknesses and resin properties are commercially available, selecting those suitable for the slot liner from these commercially available products can cause the slot liner to exhibit the desired properties. It is preferable in that it is easy.
As this PET film, not only a single-layer structure but also a three-layer structure in which a recycled material layer is sandwiched between two virgin material layers can be employed.

The polyester film constituting the first resin sheet 43 may be a stretched product or an unstretched product, and may be a surface treated product or an untreated product.
The polyester film is preferably a low oligomer product having a polybutylene terephthalate (PBT) film or a polyethylene terephthalate (PET) film and having an oligomer extraction amount of 0.5% by mass or less.
The oligomer extraction amount is obtained, for example, by boiling a 38 mm × 38 mm film in 20 cc of xylene at 139 ° C. for 2 hours, slowly cooling it, taking out the film, and measuring the amount of oligomer in the xylene. It is done.
The amount of oligomer in xylene is determined from the absorbance at a measurement wavelength of 240 nm, and is determined from a calibration curve prepared in advance for the relationship between the concentration of the oligomer and the absorbance.
In addition, the measurement of a light absorbency can use UV-VIS-NIR spectrophotometer UV-3101PC made from SHIMADZU, for example.

The polyester film has a volume resistivity of 1 × 10 ¹² Ω · cm or more (normally 1 × 10 ¹⁶ Ω · cm or less) at room temperature (for example, 30 ° C.) from the viewpoint of imparting insulation reliability to the slot liner 40. Preferably, it has a volume resistivity of 1 × 10 ¹³ Ω · cm or more.

The polyester fiber nonwoven fabric used for the second resin sheet 44 is effective in suppressing the occurrence of thermal deformation in the slot liner 40 due to the difference in thermal shrinkage between the polyester film and the aromatic polyamide paper, and the slot liner. This is effective for exhibiting excellent slipperiness between the stator 40 and the stator core 10.
That is, the slot liner 40 of this embodiment is used by being wound around the segment conductor 21 so that the second resin sheet 44 is on the outer side, so that the second resin sheet 44 is in contact with the inner wall surface of the slot groove 11. It is used for.

The polyester fiber nonwoven fabric is preferably thinner than the aromatic polyamide paper in consideration of the coil space factor.
As a polyester fiber nonwoven fabric of this embodiment, the thing of thickness 5micrometer-200 micrometers is employable, for example. In addition, the thickness of a polyester fiber nonwoven fabric can be calculated | required similarly to the thickness of aromatic polyamide paper.

It is preferable that the polyester fiber nonwoven fabric approximates the mass per unit area with the polyester film.
That is, the ratio (X1 / X2) of the basis weight (X1: g / m ² ) of the polyester fiber nonwoven fabric to the basis weight (X2: g / m ² ) of the polyester film is 0.5 or more and 2.0 or less. preferable.

As a polyester fiber nonwoven fabric of this embodiment, it can be set as the fiber nonwoven fabric which consists of a polyester-type resin illustrated about the polyester film, for example.
As the polyester nonwoven fabric, polyester resin fibers formed into a sheet using a binder, or polyester resin fibers formed into a sheet by heat fusion without using a binder are used. can do.

In addition, the binder usually contains many components having a lower melting point than fibers.
For this reason, from the viewpoint of exhibiting excellent heat resistance in the slot liner, a polyester fiber nonwoven fabric in which polyester resin fibers are heat-sealed without using a binder is used for the second resin sheet 44. Is preferred.
Among them, the polyester fiber nonwoven fabric may be a spunbond nonwoven fabric in which a continuous resin is formed by extruding a heat-melted polyester-based resin from a nozzle and the continuous fibers are heat-bonded to each other without being cooled down. preferable.
The second resin sheet 44 can exhibit excellent adhesiveness with the adhesive layer 42 by allowing the adhesive constituting the adhesive layer 42 to penetrate to a certain depth from the surface.
On the other hand, when the second resin sheet 44 is in a state in which the adhesive is likely to permeate excessively in the thickness direction, the adhesive layer 42 is applied when a force is applied to the high-temperature slot liner 40 in the thickness direction. There is a risk of greatly reducing the thickness.
For this reason, the second resin sheet 44 has a laminated structure, a first layer in contact with the adhesive layer, and a second layer in contact with the first layer from the side opposite to the adhesive layer. It is preferable that the fiber density of the second layer is higher than the fiber density of the first layer.
By adopting the polyester fiber nonwoven fabric having such a configuration for the second resin sheet 44, it is easy to keep the permeation region of the adhesive constituting the adhesive layer only in the first layer, and the adhesive reaches the second layer. Can be prevented from penetrating.
That is, by adopting the polyester fiber nonwoven fabric having such a configuration, it becomes easy to secure a desired thickness in the adhesive layer and excellent adhesion between the polyester fiber nonwoven fabric and the adhesive layer (base sheet). It becomes easy to show power.

In addition, in the polyester fiber nonwoven fabric, it is advantageous that the fiber thickness on the side in contact with the core (inner wall surface of the slot groove) is somewhat thick in order to exert the slip property with respect to the core.
Therefore, it is preferable that the said polyester fiber nonwoven fabric has a 3rd layer whose fiber thickness is thicker than a 2nd layer on the surface on the opposite side to a said 1st layer.
The slot liner 40 is a state in which the fiber density of the third layer is low to some extent when the pressure is applied in the thickness direction and the surface layer portion exhibits excellent cushioning properties and suppresses the decrease in thickness. It is preferable that
That is, the polyester fiber non-woven fabric includes a first surface layer (first layer) constituting one surface side in contact with the adhesive layer 42 and a second surface layer (other surface side in contact with the inner wall surface of the slot groove 11). It is preferable to have an intermediate layer (second layer) having a fiber density higher than that of the second surface layer and the first surface layer between the third layer and the third layer.

  As such a preferable polyester fiber nonwoven fabric, for example, a nonwoven fabric formed by a melt blow method capable of forming a nonwoven fabric having a relatively thin fiber thickness and a high fiber density in the spunbond method is used as a core material. Examples thereof include a three-layer structure of “spunbond nonwoven fabric / melt blown nonwoven fabric / spunbond nonwoven fabric” in which general spunbond nonwoven fabrics are laminated on both surfaces of the core material.

In addition, as the polyester fiber nonwoven fabric having a three-layer structure in which the first surface layer and the second surface layer are made of a general spunbond nonwoven fabric and the intermediate layer is made of a melt blown nonwoven fabric, the average fiber thickness of the intermediate layer is 1 The thickness of the intermediate layer is 5 to 40 μm, the basis weight is 10 to 30 g / m ² , and the fiber thickness of the first surface layer and the second surface layer is 5 times to 7 times the fiber thickness of the intermediate layer The fiber density is preferably 1/7 to 1/5 that of the intermediate layer.
The thickness of the fibers of the first surface layer, the second surface layer, and the intermediate layer is observed by, for example, a scanning electron microscope (SEM), and the thickness of 10 or more fibers selected at random is selected. It can be obtained by measuring and arithmetically averaging the measured values.
The fiber densities of the first and second surface layers and the intermediate layer are the apparent densities determined by the products of the thicknesses and the basis weights of the first and second surface layers and the intermediate layer, respectively. It can be determined by dividing by the true specific gravity of the polyester fiber forming the layer.
The thickness of the first surface layer impregnated with the adhesive is preferably 40 to 70% of the total thickness of the polyester fiber nonwoven fabric.
The polyester fiber nonwoven fabric having such a three-layer structure has an overall thickness of 10 to 100 μm, an overall basis weight of 10 to 100 g / m ² , and an air permeability (JISL 1913: 2010 “General nonwoven fabric test method” fragile method) Is preferably ² to 50 cm ³ / cm ² · sec.

The adhesive layer 42 for bonding the base sheet 41, the first resin sheet 43, and the second resin sheet 44 is formed of a general pressure-sensitive adhesive or a reaction-curing adhesive. be able to.
Examples of the adhesive include acrylic, rubber-based, silicone-based, and urethane-based adhesives, but an acrylic adhesive mainly composed of an acrylic polymer is preferable in terms of easily exhibiting excellent heat resistance. .

  The acrylic polymer preferably used as the main component of the adhesive is obtained by polymerizing a raw material monomer including a (meth) acrylic acid alkyl ester and a carboxyl group-containing unsaturated monomer.

  The (meth) acrylic acid alkyl ester which is the starting material for the acrylic polymer is not particularly limited, but examples thereof include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, normal propyl acrylate, normal propyl methacrylate, and isopropyl. Acrylate, isopropyl methacrylate, normal butyl acrylate, normal butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, secondary butyl acrylate, secondary butyl methacrylate, tertiary butyl acrylate, tertiary butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, normal octyl acrylate Normal normal Methacrylate, isooctyl acrylate, isooctyl methacrylate, n-nonyl acrylate, n-nonyl methacrylate, isononyl acrylate, can be employed one or more of such isononyl methacrylate.

  Further, the carboxyl group-containing unsaturated monomer which is a starting material of the acrylic polymer is not particularly limited as long as it is copolymerizable with the above (meth) acrylic acid alkyl ester. One or more of acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid and the like can be used.

The acrylic polymer may be a copolymer containing another monomer in addition to the (meth) acrylic acid alkyl ester and the carboxyl group-containing unsaturated monomer as exemplified above.
Examples of monomers other than those exemplified above include hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and hydroxyhexyl (meth) acrylate; (meth) acrylamide, acryloylmorpholine, ( Nitrogen-containing (meth) acrylates such as (meth) acrylonitrile; vinyl acetate, styrene, vinylidene chloride, vinyl propionate and the like.

Of these, the acrylic polymer is preferably a copolymer of butyl acrylate and acrylic acid.
When the acrylic polymer is a copolymer of butyl acrylate and acrylic acid, the acrylic polymer is formed so that the proportion of butyl acrylate in the total of acrylic acid is 80% by mass or more and 99% by mass or less. It is preferably used for forming an acrylic polymer so as to be 90% by mass or more and 98% by mass or less.

The acrylic adhesive preferably contains the acrylic polymer in a crosslinked state in order to exhibit excellent heat resistance in the adhesive layer.
In order to crosslink these acrylic polymers, for example, a method of irradiating active energy rays (such as ultraviolet rays and electron beams) can be employed.
In addition, any crosslinking agent can be used for crosslinking between acrylic polymers.
Examples of such a crosslinking agent include an epoxy-based crosslinking agent, a polyfunctional isocyanate-based crosslinking agent, a melamine resin-based crosslinking agent, a metal salt-based crosslinking agent, a metal chelate-based crosslinking agent, an amino resin-based crosslinking agent, and a peroxide-based crosslinking agent. A crosslinking agent etc. are mentioned.
In addition, it is also possible to construct | assemble a crosslinked structure by irradiation of active energy rays, such as an ultraviolet-ray and an electron beam, regardless of the presence or absence of use of a crosslinking agent.
In the present embodiment, the crosslinking agent used for crosslinking the acrylic polymers may be only one kind or two or more kinds.

The amount of the crosslinking agent used is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass of the acrylic polymer (acrylic polymer before crosslinking) which is the main component of the adhesive. More preferably, it is 8 parts by mass or less.
Moreover, it is preferable that the usage-amount of a crosslinking agent is 1 mass part or more with respect to 100 mass parts of acrylic polymers (acrylic polymer before bridge | crosslinking).

  Among the crosslinking agents as described above, a polyfunctional isocyanate-based crosslinking agent is particularly preferable as the crosslinking agent.

As the isocyanate-based crosslinking agent, a polyfunctional isocyanate compound is preferably used, and various compounds having two or more isocyanate groups in the molecule are included.
Typical examples thereof include diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate and the like.
The isocyanate-based crosslinking agent may be an adduct or an adduct obtained by adding tolylene diisocyanate trimer to trimethylolpropane.

The acrylic adhesive may contain any additive.
Examples of such additives include softeners, tackifiers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, heat stabilizers, polymerization inhibitors, silane cups. Examples thereof include a ringing agent, a lubricant, an inorganic or organic filler, a metal powder, and a pigment.

Examples of the tackifier include petroleum-based resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymer systems and alicyclic copolymers, and coumarone-indene systems. Examples thereof include resins, terpene resins, terpene phenol resins, rosin resins such as polymerized rosin, (alkyl) phenol resins, xylene resins or hydrogenated products thereof.
One type of tackifier may be contained in the acrylic adhesive, or two or more types may be used.

  It should be noted that if the tackifier is excessively contained, the elastic modulus of the acrylic adhesive is reduced, and therefore the content is preferably based on 100 parts by mass of the acrylic polymer that is the main component of the acrylic adhesive. Is 50 parts by mass or less, more preferably 30 parts by mass or less.

  When the adhesive layer 42 is formed, the acrylic adhesive is not particularly limited in its dosage form. Even if it is a solvent-type acrylic adhesive containing an organic solvent, an acrylic polymer or the like can be used. An emulsion acrylic adhesive in which an adhesive component is dispersed in an aqueous binder may be used.

  In providing particularly excellent heat resistance to the adhesive layer 42, the acrylic adhesive preferably contains an epoxy resin and a phenol resin.

As the epoxy resin, a bisphenol type epoxy resin, a novolac type epoxy resin, or the like can be used.
The acrylic adhesive can contain one or more epoxy resins.
Examples of the bisphenol type epoxy resin include bisphenol A type and bisphenol F type.

  As the novolac type epoxy resin, for example, ortho-cresol novolac type, phenol novolac type, glycidyl ether type epoxy resin of cresol novolac resin, or the like can be used.

Among these, the epoxy resin to be contained in the adhesive layer 42 is preferably a bisphenol A type epoxy resin, more preferably a bisphenol A type epoxy having an epoxy equivalent of 450 to 2200 g / eq, and an epoxy equivalent of 875 to 975 g / Eq bisphenol A type epoxy is particularly preferred.
In addition, this epoxy equivalent can be calculated | required by JISK7236.
The proportion of the epoxy resin in the acrylic adhesive is preferably 20 to 60% by mass, and preferably 25 to 45% by mass, based on all polymer components contained in the acrylic adhesive. More preferred.

As the phenol resin, one or two or more general phenol resins such as alkylphenol resin, paraphenylphenol resin, novolak phenol resin such as bisphenol A type phenol resin, and resole phenol resin and polyphenyl paraphenol resin are combined. Can be used.
Of these, phenol aralkyl resins such as phenol / p-xylylene glycol dimethyl ether polycondensate are preferred.
The proportion of the phenol resin in the acrylic adhesive is preferably 10 to 50% by mass, and preferably 20 to 40% by mass, based on all polymer components contained in the acrylic adhesive. More preferred.

  When an epoxy resin or a phenol resin is contained, the proportion of the acrylic polymer in the acrylic adhesive is preferably 20 to 60% by mass based on all polymer components contained in the acrylic adhesive. 30 to 50% by mass is more preferable.

When the acrylic adhesive contains a polymer component such as an epoxy resin or a phenol resin in addition to the acrylic polymer, the acrylic adhesive preferably further contains a component that serves as a curing accelerator for the epoxy resin.
Examples of the curing accelerator include imidazole compounds.
Examples of the imidazole compound include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-phenyl. -4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl- 2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2,4-diamino-6- (2-methylimidazolylethyl) -1,3,5-triazine, 2,4-diamino-6- (2- Undecylimidazolylethyl) -1,3,5 Triazine, 2,4-diamino-6- (2-ethyl-4-methylimidazolylethyl) -1,3,5-triazine, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl- 5-hydroxymethylimidazole etc. are mentioned.
Especially, it is preferable to make acrylic adhesive contain 2-undecyl imidazole.

The adhesive layer 42 can usually have a thickness of 1 to 50 μm, preferably 5 to 10 μm.
The adhesive layer 42 may have different thicknesses on one surface side of the base sheet 41 and the other surface side opposite to the one surface side, or may have a common thickness.
Further, the adhesive layer 42 may be common even if the adhesive used on one side and the other side of the base sheet 41 is different.
The slot liner 40 does not necessarily include the adhesive layer 42. For example, the base sheet 41 and the first resin sheet 43 may be in direct contact with each other by thermal lamination or the like.
In the slot liner 40, the base sheet 41 and the second resin sheet 44 may be in direct contact with each other by thermal lamination or the like.

Since the slot liner 40 of the present embodiment has the above-described configuration, it is less likely to be warped or twisted due to thermal deformation at a high temperature.
Therefore, in the slot liner 40 of the present embodiment, the electrical insulation is not easily lowered due to thermal deformation.
Therefore, the slot liner 40 of this embodiment is suitable for being used in a drive motor for a hybrid vehicle or an electric vehicle.
Moreover, although the slot liner 40 of this embodiment includes only one sheet of aromatic polyamide paper, it exhibits excellent characteristics in heat resistance, electric insulation, and slipperiness.

  In the present embodiment, a rotating electric machine in which a slot liner is used is exemplified by a coil provided with a segment conductor, but a winding in which a general round wire (an annealed copper wire) is enamel-coated. Also when used in a rotating electrical machine having a coil formed by the above, it is a range intended as an insulating paper for a rotating electrical machine of the present invention.

  Further, in the present embodiment, it is used in a state of being bent corresponding to the shape of the slot groove, a local pressure is easily applied to the fold, and a local crack or tear due to thermal deformation is suppressed. Although the slot liner is illustrated as the insulating paper for rotating electrical machines of the present invention in that the effect of the invention is more remarkably exhibited, the insulating paper for rotating electrical machines of the present invention is not limited to the slot liner. In addition, wedges and interphase insulating paper are within the scope of the present invention.

  Furthermore, the present invention is not limited to the above-described exemplary embodiment, and even if there are matters that are not directly described above, the present invention is not limited to the technical matters that have been conventionally known for rotating electrical machines and insulating paper. It is possible to employ within the range where the effect of is not significantly impaired.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to these.

(Preparation of insulating paper)
Using aromatic polyamide paper, polyethylene terephthalate film, polyethylene terephthalate fiber nonwoven fabric (spunbond nonwoven fabric / melt blown nonwoven fabric / spunbond nonwoven fabric) and urethane adhesive as shown in the table below Insulating paper for rotating electrical machines (insulating paper A to insulating paper D) having a configuration was prepared.
The insulating paper D has a three-layer structure including an adhesive layer, and the other insulating papers (insulating paper A to insulating paper C) have a five-layer structure.

(Evaluation)
The insulating paper A to insulating paper D were cut along the adhesive application direction (MD) and the direction (TD) perpendicular to the direction to produce a square test piece having a side of 10 cm.
The initial dimensions of the test piece were accurately measured, and the dimensions were measured again after heating in an oven at 230 ° C. for 500 hours.
Further, it was visually confirmed whether or not the test piece was curled after heating for 500 hours.
As a result, with the insulating paper D, the curl was large and the dimensions of the test piece after heating could not be measured accurately.
For the test pieces obtained from insulating paper A to insulating paper C, the shrinkage dimension is obtained by subtracting the dimension after heating from the initial dimension, and the ratio of the shrinkage dimension to the initial dimension is obtained as a percentage. It was set as the thermal contraction rate of the piece.
These results are also shown in the following table.
Moreover, the result of having calculated | required the thermal contraction rate in each direction (MD, TD) after progress for 24 hours, 50 hours, 100 hours, 250 hours, and 500 hours after a heating is shown to FIG.

Of the above insulating papers, the insulating paper C is the type of insulating paper exemplified in this embodiment.
Also from the above results, it can be seen that the insulating paper of the present invention can exhibit excellent insulation reliability without causing problems such as shrinkage even when exposed to high temperature conditions.

1: Stator, 10: Stator core, 11: Slot groove, 20: Coil, 40: Slot liner (insulating paper for rotating electrical machine)

Claims (1)

Used in a rotating electrical machine having a core having a plurality of slot grooves and a plurality of coils housed in the slot grooves, and is housed in the slot grooves together with the coils to provide insulation between the coils or between the coils and the cores. Insulating paper for rotating electrical machines used to secure,
It has a laminated structure in which resin sheets are laminated on both sides of the base sheet,
The base sheet is an aromatic polyamide paper,
Among the resin sheets, the first resin sheet laminated on one side of the base sheet is a polyester film, and the second resin sheet laminated on the other side of the base sheet is a polyester fiber nonwoven fabric. Insulating paper for rotating electrical machines.