Insulating material composition and rotating electrical machine comprising the same

Abstract

The present invention relates to an insulating material composition and a rotary electric machine equipped with an insulating material formed from said insulating material composition.

Description

Technology Field

[0001] The present invention relates to an insulating material composition and a rotary electric machine equipped with an insulating material formed from said insulating material composition. Background Technology

[0002] Rotating electric devices such as motors or generators include a rotor and a stator, and the stator is provided with an annular stator core having a plurality of slots in the circumferential direction of its inner surface. A coil is wound in the slot, and an insulating layer is formed between the slots and the coil within the stator to ensure electrical insulation.

[0003] Conventionally, a method has been used to form an insulating layer by inserting insulating paper between a slot and a coil within a stator. According to this method, to insert insulating paper into a rotating electric machine, it is necessary to unwind and supply the insulating paper, cut it, bend it into a predetermined shape, and then insert it into a slot or the like within the rotating electric machine. Various technologies have been proposed regarding the insulating paper and the apparatus for manufacturing it; for example, Korean Patent Publication No. 10-1999-0015205 discloses an insulating paper for a motor in which both wings and a fixing member for fixing the wings are integrated, and an apparatus for manufacturing the same.

[0004] However, since only one type of insulating paper can be manufactured using a single manufacturing device, a separate insulating paper manufacturing device must be used for each shape to manufacture insulating paper of various shapes used in various types of rotating electric machinery, resulting in significant inefficiency in terms of cost and time. In addition, conventional insulating paper has a low thermal conductivity, which is a problem as it cannot sufficiently suppress the temperature rise of rotating electric machinery.

[0005] To solve these problems, a technology using a thermosetting resin composition as an insulating material instead of insulating paper is being proposed. However, existing insulating materials using thermosetting resin compositions have the problem of not exhibiting sufficient electrical insulation properties. In particular, as motor technology advances and motor sizes become smaller, the thickness between the coil and the stator slot is becoming thinner. In this case, the thickness of the insulating material filling the space between the coil and the stator slot also becomes thinner, so an insulating material with higher electrical insulation properties is required. The problem to be solved

[0006] The present invention provides an insulating material composition with excellent insulating properties and a rotary electric device equipped with an insulating material formed from said insulating material composition. means of solving the problem

[0007] The present invention provides an insulating material composition comprising a first epoxy resin, a second epoxy resin, a curing agent, and an inorganic filler, wherein the first epoxy resin is a biphenyl ether-type epoxy resin and the second epoxy resin is a phenol aralkyl-type epoxy resin. Effects of the invention

[0008] The present invention provides an insulating material composition with excellent insulating properties and a rotary electric machine equipped with an insulating material formed from said insulating material composition. The insulating material composition according to the present invention is filled between a slot and a coil within a rotary electric machine to fill the gap between the slot and the coil and can replace insulating paper to impart insulating properties. Since the insulating material composition of the present invention exhibits superior insulating properties compared to conventional insulating material compositions containing thermosetting resins, it can be applied to rotary electric machines requiring excellent insulation, such as motors for electric vehicles. Specific details for implementing the invention

[0009] The present invention will be described in detail below. However, the scope of the present invention is not limited solely to the description below, and each component may be modified in various ways or selectively combined as needed. Accordingly, it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the present invention.

[0010] As used herein, “viscosity” is measured by conventional methods known in the art, for example, using an ICI viscometer at 150 °C. Functional groups such as “hydroxyl groups” are measured by conventional methods known in the art, for example, by titration. “Particle size (D 50 )” is measured by conventional methods known in the relevant technical field, and can be measured, for example, by laser light scattering (LLS).

[0012] Insulating material composition

[0013] The insulating material composition of the present invention comprises an epoxy resin, a curing agent, and an inorganic filler. The present invention can provide an insulating material composition having excellent electrical insulation properties by using a mixture of a biphenyl ether-type epoxy resin and a phenol aralkyl-type epoxy resin as the epoxy resin. The insulating material composition may further include additives commonly used in the relevant technical field, such as adhesion enhancers, release agents, colorants, catalysts, and flame retardants, as needed.

[0015] Epoxy resin

[0016] The insulating material composition of the present invention includes an epoxy resin. The epoxy resin serves as a main component to improve the reliability of the insulating material composition. The present invention includes a first epoxy resin, which is a biphenyl ether-type epoxy resin, and a second epoxy resin, which is a phenol aralkyl-type epoxy resin, as epoxy resins.

[0017] The above biphenyl ether type epoxy resin is a non-polar molecule that lacks partial positive and negative charge regions and does not interact strongly with an electric field, has a relatively symmetric structure with a uniform charge distribution of the molecule, and has a small number of polarizable groups that can easily react to an external electric field and become polarized, thus exhibiting superior insulation properties compared to dicyclopentadiene type epoxy (DCPD type epoxy) or ortho-cresol novolak type epoxy (OCN type epoxy).

[0018] Meanwhile, although phenol aralkyl-type epoxy resins can impart flame retardancy, the two phenyl rings are directly connected, making it prone to charge delocalization. Since charge-delocalized molecules have dipole moments and strong interactions with other molecules, using them alone may result in inferior insulation properties. In the present invention, by mixing and using a biphenyl ether-type epoxy resin as the first epoxy resin and a phenol aralkyl-type epoxy as the second epoxy resin, an insulating material composition can be provided that exhibits not only excellent flame retardancy but also excellent insulation properties.

[0020] 1st epoxy resin

[0021] The first epoxy resin mentioned above is a biphenyl ether type epoxy resin, and it serves to improve electrical insulation properties.

[0022] For example, the first epoxy resin may be a biphenyl ether type epoxy resin represented by the following chemical formula 1.

[0023] [Chemical Formula 1]

[0024]

[0025] In the above chemical formula 1,

[0026] R 1 to R 6Each is independently H, a halogen element, or an alkyl group having 1 to 5 carbon atoms.

[0027] For example, in the above chemical formula 1, R 1 to R 6 Each can independently be H, F, Cl, Br, a methyl group, an ethyl group, a propyl group, or a butyl group. As another example, R in Chemical Formula 1 above 1 to R 6 All can be H.

[0028] The first epoxy resin may have an epoxy equivalent of 130 to 200 g / eq, for example, 155 to 175 g / eq, and a melting point of 70 to 100 °C, for example, 78 to 90 °C. If the epoxy equivalent is below the aforementioned range, the adhesion properties with metal may be reduced, and if it exceeds the aforementioned range, the glass transition temperature (Tg) of the epoxy resin composition may be lowered and mechanical properties may be reduced. If the melting point is below the aforementioned range, problems with handling such as melting due to friction during the mixing process may occur, and if it exceeds the aforementioned range, it may not melt during the dispersion process and may be undispersed.

[0029] Based on the total weight of the insulating material composition, the content of the first epoxy resin may be 1 to 15 weight%, for example, 1 to 10 weight%. If the content of the first epoxy resin is less than the aforementioned range, the improvement of electrical insulation properties may be insufficient, and if it exceeds the aforementioned range, the content of the filler may decrease, and the mechanical strength may be reduced.

[0031] Second epoxy resin

[0032] The second epoxy resin mentioned above is a phenol aralkyl type epoxy resin, and the phenol aralkyl type epoxy resin containing many aromatic structures within its molecular structure plays a role in improving flame retardancy.

[0033] For example, the second epoxy resin may be a biphenyl aryl-type epoxy resin, and may be, for example, a polymer with formaldehyde, 1,1'-biphenyl and phenol, glycidyl ether.

[0034] For example, the second epoxy resin may be a phenol aralkyl type epoxy resin represented by the following chemical formula 2.

[0035] [Chemical Formula 2]

[0036]

[0037] In the above chemical formula 2,

[0038] n is an integer from 1 to 10.

[0039] The second epoxy resin may have an epoxy equivalent of 200 to 350 g / eq, for example, 270 to 285 g / eq, and a viscosity (150 °C) of 0.1 to 5 poise, for example, 0.5 to 1.1 poise. If the epoxy equivalent is less than the aforementioned range, the flame retardant properties may be reduced, and if it exceeds the aforementioned range, the mechanical properties may be reduced. If the viscosity is less than the aforementioned range, the flame retardant properties may be reduced, and if it exceeds the aforementioned range, the glass transition temperature (Tg) of the epoxy resin composition may be lowered and the mechanical properties may be reduced.

[0040] Based on the total weight of the insulating material composition, the content of the second epoxy resin may be 0.1 to 10 weight%, for example, 0.1 to 3 weight%. If the content of the second epoxy resin is less than the aforementioned range, the improvement of flame retardant properties may be insufficient, and if it exceeds the aforementioned range, the content of the filler may decrease, and the mechanical strength may be reduced.

[0042] The insulating material composition according to the present invention may include the first epoxy resin and the second epoxy resin in a weight ratio of 8 to 70:1, for example, 8 to 40:1. When the epoxy resins are mixed within the aforementioned range, superior insulating properties may be provided. If the mixing ratio of the first epoxy resin to the second epoxy resin is less than the aforementioned range, the insulating properties may be reduced, and if it exceeds the aforementioned range, the flame retardant properties may be reduced.

[0044] hardener

[0045] The insulating material composition according to the present invention includes a curing agent. The curing agent reacts with the epoxy resin to close the stator slot and the coil through curing, thereby imparting insulating properties within the stator.

[0046] As the above curing agent, a curing agent known in the art for curing with an epoxy resin may be used; for example, the above curing agent may be a phenolic compound having two or more phenolic hydroxyl groups within one molecule. For example, the above curing agent may comprise one or more selected from the group consisting of acid anhydride compounds, phenol novolak resins, cresol novolak resins, phenol aralkyl resins, and polyfunctional phenolic compounds. For example, the above curing agent may be a phenolic resin, for example, a phenol polymer with 1,4-bis(methoxymethyl)benzene. In this case, excellent curability and adhesion may be provided.

[0047] As the above curing agent, a viscosity (150°C) of 0.5 to 5 poise, for example 0.5 to 1.5 poise, may be used. If the viscosity is below the aforementioned range, the adhesion of the epoxy resin composition may be reduced, and if it exceeds the aforementioned range, the glass transition temperature (Tg) of the epoxy resin composition may be lowered and the mechanical properties may be reduced.

[0048] As the above curing agent, a hydroxyl group equivalent of 100 to 230 g / eq, for example 150 to 200 g / eq, may be used. If the hydroxyl group equivalent is less than the aforementioned range, the adhesion of the epoxy resin composition may be reduced, and if it exceeds the aforementioned range, the glass transition temperature (Tg) of the epoxy resin composition may be lowered and the mechanical properties may be reduced.

[0049] The above-mentioned curing agent may be one having an electrical conductivity of 25 μS / cm or less and a volatile content of 0.2% or less. If the electrical conductivity exceeds the aforementioned range, the insulation properties may be insufficient.

[0050] Based on the total weight of the insulating material composition, the content of the curing agent may be 0.1 to 15 weight%, for example, 1 to 10 weight%. If the content of the curing agent is less than the aforementioned range, curability and moldability may be reduced, and if it exceeds the aforementioned range, reliability and strength may be reduced due to increased moisture absorption.

[0052] Inorganic filler

[0053] The insulating material composition according to the present invention includes an inorganic filler. The inorganic filler serves to impart strength to the insulating material composition, control flowability to improve moldability, and enhance durability.

[0054] The above inorganic filler may be formed from any one or at least two combinations selected from non-metal oxides, metal nitrides, non-metal nitrides, inorganic hydrates, or inorganic salts, and may be used in combination with, for example, silica, silica nitride, alumina, alumina nitride, boron nitride, etc. As an example, the above inorganic filler may be silica.

[0055] For example, the average particle size (D) of the above-mentioned inorganic filler 50 ) can be used with a thickness of 10 to 30 μm, for example, 15 to 25 μm.

[0056] Based on the total weight of the insulating material composition, the content of the inorganic filler may be 50 to 90 weight%, for example, 80 to 90 weight%. If the content of the inorganic filler is less than the aforementioned range, the mechanical strength of the cured product of the insulating material composition may be lowered and the moisture absorption may increase, which may reduce reliability; if the resin content is excessive, the resin may decompose when exposed to high temperatures, increasing the high-temperature mass loss rate and reducing insulation performance; and if it exceeds the aforementioned range, the fluidity may decrease, which may result in poor moldability.

[0058] additives

[0059] The insulating material composition according to the present invention may further include additives commonly used in the relevant technical field, such as adhesion enhancers, release agents, colorants, catalysts, and flame retardants, as needed.

[0060] The adhesion enhancer is intended to improve the adhesion between organic-inorganic bonds and metal substrates, and may use epoxy silane, amino silane, mercapto silane, acrylic silane, vinyl silane, etc. The release agent is intended to improve the release properties between the epoxy molding compound (EMC) and the external mold, and may use side-chain epoxy-modified silicone oil, side-chain amine-modified silicone oil, paraffin wax, carnauba wax, polyethylene wax, ester wax, long-chain fatty acids, metal salts of long-chain fatty acids, etc. In addition, additives such as colorants to impart color to the resin composition (e.g., carbon black, Bengala, etc.), catalysts to improve curing speed and workability (e.g., phosphorus-based catalysts, imidazole-based catalysts, etc.), and flame retardants (e.g., phosphorus-based flame retardants, metal hydroxides, etc.) may be further included.

[0061] The above additives may be added within a content range that does not impair the physical properties of the insulating material composition of the present invention, and for example, may be included in an amount of 0.01 to 10 weight% each with respect to the total weight of the insulating material composition, but are not limited thereto.

[0063] Rotating electric machine

[0064] The present invention provides a rotary electric device equipped with an insulating material formed from the aforementioned insulating material composition. The rotary electric device may be a vehicle component, for example, a motor.

[0065] For example, the present invention provides a rotary electric machine comprising a rotor and a stator, wherein the stator has an annular stator core having a plurality of slots in the circumferential direction of its inner surface, a coil is wound in the slots, and an insulating material according to the present invention is provided between the slots and the coils.

[0066] Since the insulating material according to the present invention exhibits excellent insulating properties, it can be applied as an insulating material to provide insulating properties between coils in rotating electric devices where the rotational speed and current applied to the stator increase as a large torque is required, such as electric vehicle motors.

[0068] The present invention will be explained in more detail below through examples. However, the following examples are intended only to aid in understanding the present invention and do not imply that the scope of the present invention is limited to these examples in any way.

[0070] [Experimental Example 1-12]

[0071] Insulating material compositions for each experimental example were prepared by mixing each component according to the compositions listed in Tables 1 and 2 below.

[0073]

[0074]

[0075] Epoxy resin 1: Biphenyl ether type epoxy (4,4'-dihydroxydiphenyl ether diglycidyl ether, Cas. No. 19389-73-2, epoxy equivalent 168 g / eq, melting point 79 ℃)

[0076] Epoxy resin 2: Phenol aralkyl type epoxy (Formaldehyde, polymer with 1,1'-biphenyl and phenol, glycidyl ether, Cas. No. 1201169-35-8, epoxy equivalent 274 g / eq, viscosity (150 ℃) 0.9 poise)

[0077] Epoxy resin 3: Dicyclopentadiene type epoxy (HP-7200, DIC)

[0078] Epoxy Resin 4: Ortho-Cresol Novolac epoxy (YDCN-500-4P, Kukdo Chemical)

[0079] Epoxy Resin 5: Biphenyl type epoxy (YX-4000HK, MITSUBISHI CHEMICAL)

[0080] Curing agent: Phenol polymer with 1,4-bis(methoxymethyl)benzene (Cas. No. 0026834-02-6, hydroxyl equivalent 175 g / eq, viscosity (150 ℃) 0.95 poise)

[0081] Filler: Silica (surface-treated silicon dioxide, D 50 18 µm)

[0082] Silane: Trimethoxy[3-(phenylamino)propyl]silane

[0083] Wax: Ester wax

[0084] Coloring agent: Carbon black

[0085] Catalyst: A mixture of triphenylphosphine and 5-methyl-2-phenylimidazole-4-methanol (2:8 weight ratio)

[0086] Flame retardant: Poly(bis(phenoxy)phosphazene)

[0088] [Physical Property Evaluation]

[0089] The physical properties of the insulating material composition of each experimental example were measured using the following method, and the results are listed in Tables 3 and 4 below.

[0091] Spiral flow (S / F)

[0092] Flowability was measured using an evaluation mold with a transfer molding press (175 ℃, 70 kgf / ㎠).

[0094] Gel Time (G / T)

[0095] The time from the point of melting to the point of gelation was measured on a 175 ℃ hot plate.

[0097] withstand voltage test

[0098] Specimens with a diameter of 30 mm were fabricated using a transfer molding press (175 ℃, 70 kgf / ㎠). After applying a predetermined voltage to each specimen, the leakage current was measured and evaluated according to the following criteria.

[0099] [metewand]

[0100] ○: When voltage is applied for more than 1 minute, leakage current 50 mA or less

[0101] △: Voltage applied for more than 30 seconds but within 1 minute, leakage current exceeding 50 mA

[0102] X: Leakage current exceeding 50 mA within 30 seconds of applying voltage

[0104]

[0105]

[0106] As shown in Tables 3 and 4 above, the insulating material compositions of Experimental Examples 1-9 according to the present invention exhibited excellent physical properties across all measurement items. On the other hand, it can be confirmed that the insulating material compositions of Experimental Examples 10-12, which do not contain biphenyl ether-type epoxy resin (epoxy resin 1), showed inferior results in dielectric strength evaluation compared to Experimental Examples 1-9.

Claims

Claim 1 An insulating material composition comprising a first epoxy resin, a second epoxy resin, a curing agent, and an inorganic filler, wherein the first epoxy resin is a biphenyl ether-type epoxy resin and the second epoxy resin is a phenol aralkyl-type epoxy resin, wherein the first epoxy resin and the second epoxy resin are included in a weight ratio of 8 to 70:1, wherein the first epoxy resin is a biphenyl ether-type epoxy resin represented by the following Chemical Formula 1 and the second epoxy resin is a phenol aralkyl-type epoxy resin represented by the following Chemical Formula 2: [Chemical Formula 1] In the above chemical formula 1, R 1 to R 6 Each is independently H, a halogen element, or an alkyl group having 1 to 5 carbon atoms, [Chemical Formula 2] In the above chemical formula 2, n is an integer from 1 to 10. Claim 2 delete Claim 3 An insulating material composition according to claim 1, wherein the epoxy equivalent of the first epoxy resin is 130 to 200 g / eq and the melting point is 70 to 100 ℃, the epoxy equivalent of the second epoxy resin is 200 to 350 g / eq and the viscosity (150 ℃) is 0.1 to 5 poise. Claim 4 An insulating material composition according to claim 1, wherein the curing agent is a phenolic resin, the viscosity (150 ℃) of the curing agent is 0.5 to 5 poise, the hydroxyl group equivalent is 100 to 230 g / eq, the electrical conductivity is 25 μS / cm or less, and the volatile matter is 0.2% or less. Claim 5 An insulating material composition according to claim 1, comprising, based on the total weight of the insulating material composition, 1 to 15 weight% of the first epoxy resin, 0.1 to 10 weight% of the second epoxy resin, 0.1 to 15 weight% of the curing agent, and 50 to 90 weight% of the inorganic filler. Claim 6 delete Claim 7 A rotary electric device equipped with an insulating material formed from an insulating material composition according to any one of claims 1 and 3 to 5.

Images