JP2020070393A - Resin composition, and rotor core - Google Patents

Abstract

To provide a novel resin composition for magnet fixing that has high flowability at room temperature before curing, and has high mechanical strength after curing.SOLUTION: A resin composition for magnet fixing is for fixing a magnet in a slot of a rotor core. The resin composition for magnet fixing contains a resol type phenol resin and an inorganic filler, and the content of the inorganic filler is 30 mass% or more of the resin composition for magnet fixing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resin composition for fixing a magnet inside a slot provided in a rotor core, and a rotor core in which a magnet is fixed by the resin composition.

  Drive motors and the like mounted on hybrid vehicles, electric vehicles, and the like are provided with a slot portion for inserting a magnet at an inner edge portion of a rotor core thereof. In the rotor core, after inserting magnets into the respective slot portions, resin is injected into a gap portion formed between the slot portions and the magnets, and the resin is cured to fix and seal the magnets.

  As a resin material for fixing and sealing the magnet, a material having a composition similar to that of a semiconductor sealing material is used, and a resin material containing an epoxy resin, a novolac type phenol resin, an epoxy curing agent, and an inorganic filler as a main component is used. Widely used.

  For example, Patent Documents 1 to 3 disclose a resin composition containing an epoxy resin as a main component and used for fixing a magnet, which can be used at high temperature for a long time.

JP, 2014-132802, A JP, 2013-183627, A JP, 2013-183629, A

  The epoxy resin contained as a main component in the resin compositions described in Patent Documents 1 to 3 has a high curing temperature and a long time until the curing reaction is completed. Therefore, in the resin compositions described in Patent Documents 1 to 3, it is necessary to add a large amount of a curing accelerator to the epoxy resin. However, when a large amount of a curing accelerator is added to the resin composition, the reaction proceeds at room temperature. For this reason, the resin compositions described in Patent Documents 1 to 3 cannot store the resin composition stably at room temperature, and further have a problem that the fluidity decreases over time. Further, in order to fix the magnet inside the slot, a resin composition containing an epoxy resin as a main component has a problem that mechanical strength is insufficient.

  The present invention has been made in view of the above problems, and an object thereof is a resin composition used for fixing a magnet to a slot of a rotor core, which has high fluidity when melted and is heated. An object of the present invention is to provide a resin composition having high mechanical strength after curing and capable of being stably stored at room temperature, and a related technique thereof.

  In order to solve the above problems, a resin composition according to an aspect of the present invention is a resin composition for fixing a magnet inside a slot provided in a rotor core, and a phenol resin and an inorganic filler. In addition, the phenol resin contains at least a resol-type phenol resin, and the content of the inorganic filler is 30% by mass or more based on the total amount of the phenol resin and the inorganic filler.

  According to the present invention, a resin composition used for fixing a magnet to a slot of a rotor core, having high fluidity when melted, high mechanical strength after heat curing, and stable storage at room temperature. It is possible to provide a novel resin composition that can be obtained, and a related technique thereof.

(A) is a top view which shows the outline of the rotor core which fixes a magnet with the resin composition which concerns on 1 aspect of this invention, (b) is an A-A 'arrow sectional view in the said rotor core.

  The composition of the magnet fixing resin composition according to this embodiment will be described in detail below. Hereinafter, the magnet-fixing resin composition is also simply referred to as a resin composition. Unless otherwise specified in this specification, “A to B” representing a numerical range means “A or more and B or less”.

  In the present specification, the “resin composition” means a resin composition which is in a state before being poured into the slots and solidifying, that is, a state in which the resin composition is not cured by heating. Here, the “resin composition” is not limited in its shape such as powder, particles, and tablets. Further, in the present specification, the “molded product” means, for example, a “resin composition” molded into a powder form, a particle form, a tablet form, or the like. Further, in the present specification, the “fixing member” means a member obtained by heating and curing the “resin composition” (or “molded product”).

<Resin composition>
The resin composition according to one aspect of the present invention contains a phenol resin and an inorganic filler.

  This makes it possible to obtain a resin composition having high fluidity when melted and high mechanical strength after heat curing. Therefore, it can be suitably used as a resin composition for fixing the magnet inside the slot provided in the rotor core.

[Phenolic resin]
The phenol resin functions as a binder for the inorganic filler in the resin composition. Phenolic resins are generally obtained by reacting phenols with aldehydes, and are divided into resol-type phenol resins and novolac-type phenol resins depending on the synthesis conditions.

  In the present specification, when simply described as "phenolic resin", the "phenolic resin" means both "resole type phenolic resin" and "novolak type phenolic resin", or "resole type phenolic resin". The meaning of any one of "novolak type phenolic resin" is included. Further, the "resole resin" means "resole type phenol resin" and the "novolak resin" means "novolak type phenol resin".

(Resol type phenol resin)
A resin composition according to an embodiment of the present invention contains at least a resol-type phenol resin as a phenol resin. Since the resin composition contains at least a resol-type phenol resin as the phenol resin, a resin composition having high stability when stored at room temperature can be obtained. Further, by containing the resol-type phenol resin, it is possible to obtain a resin composition capable of molding a fixing member having high mechanical strength by heating and curing. Here, the mechanical strength is typically bending strength.

  Raw materials used for synthesizing the resol-type phenol resin can include phenols and aldehydes, which are polymerized in the presence of a basic catalyst, a divalent metal salt catalyst, or the like.

  Examples of phenols include phenol, cardanol, cashew nut shell liquid, and examples of other phenols include cresols, xylenols, alkylphenols, bisphenols, and polyphenols. .. Here, examples of cresols include o-cresol, m-cresol, and p-cresol, and examples of xylenols include 2,3-xylenol, 2,4-xylenol, 2, and the like. Examples thereof include 5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol. Examples of the alkylphenols include butylphenol such as isopropylphenol, p-isobutylphenol and p-tert-butylphenol, alkylphenol such as p-octylphenol, p-nonylphenol and p-cumylphenol. Examples of bisphenols include bisphenol A, bisphenol F, and bisphenol S. Examples of polyphenols include resorcin, pyrogallol, and catechol. Of these phenols, it is more preferable to use phenol, cresols, cardanol, cashew nut shell liquid, bisphenol A, etc. as raw materials for the phenol resin, whereby curability and mechanical strength such as toughness A phenol resin having an excellent balance can be obtained. In addition, these phenols can be used individually or in mixture of 2 or more types.

  Examples of aldehydes include formaldehyde, paraformaldehyde, trioxane, acetaldehyde, propionaldehyde, glyoxal, benzaldehyde, and salicylaldehyde. Among these aldehydes, the curability of the phenol resin can be increased. It is more preferable to use formaldehyde, paraformaldehyde and the like from the viewpoints of being able to do so and cost. In addition, these aldehydes can be used individually or in mixture of 2 or more types.

  The weight average molecular weight of the resol type phenol resin is preferably 1,800 to 8,500, more preferably 2,000 to 7,500. The reason why the weight average molecular weight of the resol type phenol resin is preferably 1,800 to 8,500 is as follows.

  The first reason is that when the resin composition is produced, the smaller the weight average molecular weight of the resol-type phenol resin is within the range of 1,800 to 8,500, the more the resin composition is gelled in the production facility. That is, it is possible to prevent more effectively. Thereby, the resin composition and its molded product can be stably produced. Further, as the weight average molecular weight of the resol-type phenol resin is larger within the range of 1,800 to 8,500, blocking of the molded product molded from the resin composition can be preferably prevented.

  The second reason is that when the manufactured resin composition is injected into the slots of the rotor core, the smaller the weight average molecular weight of the resol-type phenolic resin is within the range of 1,800 to 8,500, the preheater and This is to improve the fluidity of the resin composition when the molten resin composition is injected into the slots provided in the rotor core by preheating with the heating cylinder and the pot. Thereby, the amount of the cured product of the resin composition remaining inside the pot can be reduced.

  The third reason is that the weight average molecular weight of the resol-type phenol resin is 1,800 to 8, after the magnet is fixed by the fixing member obtained by injecting the resin composition into the slot and curing the resin composition. The larger the value within the range of 500, the higher the heat resistance and mechanical strength of the fixing member can be. As a result, it is possible to obtain a rotor core capable of suppressing cracking of the fixing member made of a cured product of the resin composition due to vibration or the like generated when the motor is used.

  The form of the resol-type phenol resin to be blended with the resin composition may be any of an aqueous solution, an alcohol solution, and one containing no solvent, but using a solid resol-type phenol resin which is a solventless type, It is more preferable from the viewpoint that it is possible to suitably prevent blocking when the molded product molded from the resin composition becomes clay-like.

  Further, the form of the resol-type phenol resin to be blended with the resin composition may be appropriately selected depending on the method of injecting the molded product of the resin composition into the slot portion of the rotor core. For example, in the case of producing a resin composition used for transfer molding, the weight average molecular weight of the resol-type phenol resin should be smaller within the range of 1,800 to 8,500 from the viewpoint of increasing the fluidity of the resin composition. In the case of producing a resin composition used for injection molding, it is possible to obtain a solid granular molding capable of suppressing blocking, which facilitates the introduction of the material from the injection molding machine hopper into the heating cylinder. From the viewpoint, it is preferably larger in the range of 1,800 to 8,500.

(Novolak type phenolic resin)
The resin composition more preferably contains a novolac type phenol resin.

  Since the resin composition contains the novolac type phenolic resin, it is possible to enhance the fluidity when the resin composition is melted. Further, by using the resol-type phenol resin and the novolac-type phenol resin together, the novolac-type phenol resin can be cured by the functional group of the resol-type phenol resin. That is, by using the resol-type phenol resin and the novolac-type phenol resin in combination, the resin composition has high mechanical strength provided by the resol-type phenol resin, and has high flowability when melted provided by the novolac-type phenol resin. It can have sex. Therefore, when the molten resin composition is injected into the gap between the slot and the magnet, it can be injected into a thinner gap. Further, it is possible to impart high toughness and high mechanical strength to the fixing member obtained by heating and curing the resin composition.

  The weight average molecular weight of the novolac type phenolic resin contained in the resin composition is preferably 800 to 7,000, more preferably 1,500 to 6,000. The smaller the weight average molecular weight of the novolac type phenol resin in the range of 800 to 7,000, the higher the fluidity can be imparted to the molten resin composition. Further, as the weight average molecular weight of the novolac type phenol resin is larger in the range of 800 to 7,000, higher mechanical strength can be imparted to the fixing member obtained by heating and curing the resin composition.

  The raw materials used for synthesizing the novolac type phenol resin can include phenols and aldehydes. By polymerizing these raw materials in the presence of an acid catalyst or the like, a novolac type phenol resin is produced. Phenols and aldehydes are the same as those used for synthesizing resol type phenolic resins.

  Further, the novolac type phenol resin may be modified with an elastomer. Examples of the constitutional unit of the elastomer in the elastomer-modified novolac phenolic resin include constitutional units containing acrylic rubber, styrene butadiene rubber, acrylonitrile butadiene rubber, isoprene rubber, silicone resin, and the like, and cardanol. Dry oils such as cashew nut shell liquid, tung oil, and rosin can be used as constituent units of the elastomer. Among these, the constituent units of the elastomer are more preferably acrylic rubber and acrylonitrile butadiene rubber, for example. By modifying the novolac type phenol resin with acrylic rubber and / or acrylonitrile butadiene rubber, it is possible to impart high heat resistance and high toughness to the molded product molded from the molding material.

(Compounding ratio of phenol resin)
When the resole-type phenol resin and the novolac-type phenol resin are used together, the mass ratio of the resole-type phenol resin and the novolac-type phenol resin (resole-type phenol resin / novolac-type phenol resin) is 95/5 to 5/95. Is preferable, and 90/10 to 10/90 is more preferable. If the resol type phenol resin / novolac type phenol resin (mass ratio) is 95/5 or less, the fluidity of the resin composition will be high. Further, when the resole-type phenol resin / novolac-type phenol resin (mass ratio) is 5/95 or more, it is possible to shorten the time when the resin composition can be removed from the mold in transfer molding, for example. Further, when the resin composition is injected into the thin gap between the slot portion and the magnet, the time for curing can be shortened. Furthermore, the mechanical strength of the fixing member obtained by heat-curing the molded product can be increased.

(Other resins)
The resin composition according to one aspect is an effect of the present invention, an effect that can be stably stored at room temperature, and an amount other than the phenol resin, in an amount that does not impair mechanical strength. May be included. Examples thereof include epoxy resin, urethane resin, unsaturated polyester resin, melamine resin, urea resin, furan resin and the like.

  Further, as the other resin, a thermosetting resin such as a silicone resin, an elastomer such as styrene-butadiene rubber, acrylonitrile-butadiene rubber, polyvinyl butyral or the like may be blended as a stress relaxation agent.

[Curing aid]
The resin composition according to the present embodiment preferably contains a curing aid for curing the phenol resin. The curing aid for curing the phenolic resin has a viewpoint that it does not corrode the surrounding metal even if the curing aid is diffused from the cured fixing member, and the curing of the resole resin is near room temperature. An alkali compound is preferable from the viewpoint that it does not proceed and is excellent in storage stability at room temperature. Preferred are alkaline metal oxides and alkaline metal salts, and more specific examples thereof include calcium hydroxide, calcium oxide, and magnesium oxide.

  Although amines function as curing aids, these amines are gradually released from the cured fixing member and corrode surrounding metals, which is not preferable. Further, although a protonic acid and a Lewis acid function as a curing aid, curing of the resole resin proceeds even at around room temperature, which is not preferable from the viewpoint of storage stability at room temperature.

[Inorganic filler]
As the inorganic filler contained in the resin composition, known ones can be used. For example, silica, calcium carbonate, talc, calcined clay, uncalcined clay, alumina, aluminum hydroxide, glass fiber, carbon fiber, and other inorganic fillers used in general resin compositions can be used. The inorganic filler may be used alone or in combination of two or more. The inorganic filler is preferably silica from the viewpoint that it does not expand even under high humidity conditions and the volume is kept constant.

  The shape of silica is not particularly limited, and examples thereof include ground silica and spherical silica, but spherical silica is preferable. By using spherical silica, the fluidity of the resin composition is high, and it is possible to reduce equipment wear that occurs during the production of the resin composition and during the molding of the molded product.

  Further, the surface of the inorganic filler may be surface-treated with a surface treatment agent or the like. For example, when the inorganic filler is silica, silica which has been surface-treated by reacting silica with a silane coupling agent may be used. By thus performing the surface treatment, the interfacial adhesion strength with the phenol resin can be improved.

  The average particle size of the inorganic filler is preferably 1 μm to 200 μm, more preferably 10 μm to 180 μm, and particularly preferably 80 μm to 180 μm. If the average particle size of the inorganic filler is 1 μm or more, the fluidity is excellent, and if it is 200 μm or less, the resin composition component can be uniformly injected even when the gap between the slot and the magnet is very thin. Become. Here, the average particle diameter refers to the median diameter (D50) in the cumulative (or frequency) distribution.

  The compounding ratio of the phenol resin contained in the resin composition and the inorganic filler is preferably such that the mass ratio of the phenol resin to the inorganic filler (phenol resin / inorganic filler) is 5/95 to 70/30. / 83 to 67/33 is more preferable. If the mass ratio of the phenol resin to the inorganic filler is 5/95 or less, the fluidity of the resin composition is high, and if it is 70/30 or more, the mechanical strength of the molded product is high.

[Other fillers]
Further, the resin composition according to the present embodiment requires an organic filler such as wood powder, coconut shell, chaff, pulp, kenaf, cotton thread, polyester fiber, vinylon fiber, acrylic fiber, and aramid fiber, in addition to the inorganic filler. You may mix | blend according to it.

[Other ingredients]
It may contain components that are mixed with a general resin composition, such as a release agent, a colorant, a coupling agent, a stress relaxation agent, a flame retardant, and a filler surface treatment agent. Examples of the colorant include known pigments such as carbon black, titanium oxide, barium sulfate, iron black, and red iron oxide, and known dyes such as aniline black and alizanin. Examples of the release agent include known release agents such as synthetic polyethylene wax, silicone wax, carnauba wax, montanic acid wax, fatty acid metal soap such as zinc stearate, fatty acid ester, and fatty acid amide. Examples of the flame retardant include red phosphorus, phosphoric acid ester, aluminum hydroxide and the like. Further, the surface treatment agent for the filler may include a cationic ammonium salt, and a coupling agent, and examples of the coupling agent include an amino group, a mercapto group, a carboxyl group, an epoxy group, an isocyanate group, and a vinyl group. A coupling agent having an unsaturated double bond can be used, and among these, it is more preferable to use a coupling agent having an amino group or an epoxy group.

[Shape of resin composition]
The form of the resin composition according to the present embodiment is not particularly limited, and examples thereof include powder form, granular form, granular form, tablet form obtained by compressing these, liquid form and the like. From the viewpoint of easy workability of the resin composition for molding, transportation, storage, etc., it is preferably any one of powder, granule, granule, and tablet.

[Method for producing resin composition]
In the method for producing the resin composition, the phenol resin and the inorganic filler may be mixed, and then the mixture may be crushed by a crusher to form powder and granules. When a resol-type phenol resin containing a solvent is used, the solvent contained in the resin composition may be removed in one embodiment.

  Examples of the mixing device for mixing the phenolic resin and the inorganic filler include a biaxial roll type mixing device, a single or twin screw extruder, a Henschel mixer, a pressure kneader, and a Banbury mixer. it can. The conditions for mixing in the mixing device may be appropriately designed in consideration of the scale of the device and the mixing efficiency of the resin composition.

  Examples of a crusher for crushing the resin composition include a speed mill having a screen (perforated plate). The hole diameter of the screen is not particularly limited, but it is preferably 0.1 to 10.0 mm from the viewpoint of being easily utilized for molding.

  After the resin composition is roughly crushed, a granular, powdery, or mixed resin composition of granular and powdery can be obtained. By this, the mixture may be crushed into particles and formed into a tablet shape, for example.

  The granulated and powdered resin composition after crushing is stirred while heating the resin composition at a temperature not lower than the melting point of the phenol resin and not higher than the curing temperature. You may melt | dissolve a phenol resin and bind an inorganic filler with the said phenol resin component, and may make it a granular form.

  Moreover, you may shape | mold in a tablet shape etc. by using a metal mold | die. This facilitates workability such as application to the rotor core and storage.

  It goes without saying that the mixing of the resin composition, the removal of the solvent, the crushing of the resin composition, the granulation, and the molding into tablets are all preferably carried out at a temperature at which the phenol resin is not cured.

[Physical properties of resin composition]
Hereinafter, the physical properties of the resin composition according to this embodiment and the molded product thereof will be described.

(Thin wall fluidity)
The resin composition according to the present embodiment has excellent thin-wall fluidity when melted. The thin-wall fluidity of the resin composition will be described. As a transfer molding device, a transfer molding press TFP12-16 (12 tons manufactured by Towa Seiki) is used. A transfer-molding die set to a transfer molding machine, having a thickness of 0.10 mm, a width of 5.00 mm, and a length of 70 mm and having a thin linear flow path, is heated to 175 ° C. to obtain a flaky resin composition. .. The time point immediately after the flaky resin composition is demolded is defined as "immediately after production".

  10.0 g of the resin composition is put into the pot of the apparatus and immediately pressurized with a plunger pressure of 2.9 MPa or 5.9 MPa. The resin composition is demolded from the mold 120 seconds after the start of pressurization, and the length of the flaky resin composition at that time is 2.5 cm or more regardless of whether the plunger pressure is 2.9 MPa or 5.9 MPa. Is preferred.

(Material fluidity due to aging: Spiral flow retention rate)
A transfer molding press TFP12-16 is used as the transfer molding device. The mold for spiral flow measurement conforming to EIMS T901 set in the transfer mold device is heated to 175 ° C. 20.0 g of the resin composition is put into the pot of the apparatus and immediately pressurized with a plunger pressure of 2.9 MPa. The resin composition is released from the mold 120 seconds after the start of pressurization, and the length of the spiral resin composition at that time is preferably 20.0 cm or more.

  As a specific method for adjusting the length of the spiral resin composition immediately after production to about 20.0 cm or more, for example, the following methods (1) to (4) can be mentioned.

  (1) A method of using a resol-type phenol resin having a small weight average molecular weight so that the melt viscosity of the resin composition becomes low at the mold temperature at the time of measurement.

  (2) A method of using a novolac type phenol resin having a small weight average molecular weight so that the melt viscosity of the resin composition becomes low at the mold temperature at the time of measurement.

  (3) A method in which the mass ratio of the resol-type phenol resin / novolak-type phenol resin is reduced and the gelation time of the phenol resin component in the resin composition is lengthened.

(4) A method of decreasing the melt viscosity of the resin composition by reducing the compounding ratio of the inorganic filler compounded in the resin composition.
One of these methods (1) to (4) may be used alone, or a plurality of methods may be used in combination.

Further, when the spiral flow (flowability) of the spiral resin composition was further measured at a storage temperature of 5 ° C. and 2688 hours (16 weeks) at 25 ° C., the spiral flow retention calculated according to the following (Formula 1) was maintained. The value of the ratio is preferably in the range of 50 to 150%. According to this, the resin composition can be stored at room temperature (about 25 ° C.) without storing it at a low temperature (about 5 ° C.). The spiral flow retention rate is the ratio of the fluidity value after storage at a predetermined temperature for a predetermined time to the fluidity value of the resin composition.
Spiral flow retention rate (%) = 100 × (X2) / (X1) (Equation 1)
Here, (X1) is a spiral flow measurement value of the resin composition, and (X2) is a spiral flow value of the resin composition after a specified time at a resin composition storage temperature of 5 ° C. or 25 ° C.

(Bending strength)
The preferable bending strength of the fixing member manufactured from the resin composition will be described. According to JIS K6911, a resin composition is molded by transfer molding at a mold temperature of 175 ° C. for 3 minutes to produce a test piece (molded product) having a length of 100 mm, a width of 10 mm and a thickness of 4 mm for measuring bending strength. To do. The prepared test piece is cured by heat treatment at 175 ° C. for 4 hours, cooled to room temperature, and then the flexural strength value measured by Strograph VC10-C (manufactured by Toyo Seiki) is preferably 80 MPa or more. , 110 MPa or more is more preferable. If the value of the bending strength is 80 MPa or more, it can be said that the molded product used for fixing the magnet has sufficient mechanical strength.

(ATF resistance test: flexural strength, flexural strength retention rate)
The bending strength of the fixing member after being immersed in ATF (Automatic Transmission Field) will be described. The fixing member according to the present embodiment preferably has a bending strength retention rate of 90% or more after a test piece manufactured by the same method as (bending strength) is immersed in ATF at 150 ° C. for 2000 hours. The flexural strength retention rate is calculated according to the following (formula 2).
Bending strength retention rate (%) = 100 × (S2) / (S1) (Equation 2)
Here, (S1) is the bending strength before soaking in ATF, and (S2) is the bending strength after soaking in ATF at 150 ° C. for 2000 hours. Bending strength is measured by the same method as (bending strength).

  The ATF used here is not particularly limited as long as it is generally used, and the base oil contains various additives. The base oil may be a mineral oil-based base oil, a synthetic oil-based base oil, or a mixture thereof. Examples of the additive component include a viscosity modifier and a friction modifier.

(ATF resistance test: weight change rate, volume change rate)
Further, for the test piece manufactured by the same method as the above-mentioned (bending strength), the weight (W1) and volume (V1) of the test piece before ATF immersion and the weight (W2) and volume (V2) of the test piece after ATF immersion were used. ) Is measured, and the rate of change in weight and the rate of change in volume are calculated according to the following (formula 3) and (formula 4). The time of immersion in ATF is, for example, 500 hours, 1000 hours, and 2000 hours. The weight change rate of the test piece after each time immersion is preferably −1.00 to 1.00%, more preferably −0.75 to 0.75%, and −0.5 to It is particularly preferably 0.5%. Further, the volume change rate of the test piece after each time immersion is preferably −1.00 to 1.50%, more preferably −0.75 to 1.00%, and −0.50. It is particularly preferable that the content is 0.50%.
Weight change rate (%) = 100 × (W2-W1) / W1 ... (Formula 3)
ATF volume change resistance (%) = 100 × (V2-V1) / V1 ... (Formula 4)
<Rotor core>
A rotor core having a magnet fixed by the resin composition according to the embodiment of the present invention is also included in the scope of the invention.

  The fixing of the magnet with the resin composition is performed by injecting the resin composition into the gap between the slot and the magnet and then curing the resin composition. As a method for molding the fixing member when curing the resin composition, a molded product may be molded by a known method such as compression molding, transfer molding, injection molding, and extrusion molding.

  An example of the rotor core filled with the resin composition will be described with reference to FIG.

  1A is a top view showing an outline of a rotor core 110 fixing a magnet with a resin composition according to an aspect of the present invention, and FIG. 1B is an AA ′ in the rotor core 110. FIG. As shown in FIG. 1A, the rotor 100 includes a rotor core 110, a slot portion 130 provided on the inner peripheral edge of the rotor core, and a magnet 120 inserted in the slot portion 130. As shown in FIG. 1A, the rotor core 110 has a donut-shaped disc shape with the point A as the center point. In addition, as shown in FIG. 1B, the rotor core 110 is configured by laminating a plurality of electromagnetic steel plates 112. The rotor 100 is used as a drive motor mounted on, for example, a hybrid vehicle and an electric vehicle by mounting an end roller indicated by a broken line and feeding a shaft (rotor). The resin composition according to an aspect of the present invention is injected into the gap between the inner wall of the slot portion 130 and the magnet 120 to fix the magnet 120 inserted in the slot portion 130, and then cured. Here, since the rotor core 110 is formed of the resin composition according to one aspect, the mechanical strength, especially the bending strength is increased. Therefore, the durability of the drive motor can be improved. Therefore, a rotor core manufactured using the resin composition according to one aspect is also within the scope of the present invention.

  Further, the resin composition according to the present embodiment can be used for coil encapsulation, electric parts, mechanical parts, consumer parts, etc. as applications.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

  Resin compositions (resin compositions for fixing magnets) of Examples 1 to 15 and Comparative Examples 1 and 2 were produced, and then thin-wall fluidity of each resin composition and a molded product obtained by curing each resin composition were prepared. The bending strength was evaluated.

[Preparation of resin composition]
Details of each material used in Examples 1 to 15 and Comparative Examples 1 and 2 are as follows.
<< Resol type phenol resin >>
Resol type phenol resin PS-4122B (resol type solid phenol resin, Mw = 6,900, solid content 100%, manufactured by Gunei Chemical Industry Co., Ltd.)
Resol-type phenol resin PL-2211 (methanol-soluble resol-type phenol resin, Mw = 2,120, solid content 60%, Gunei Chemical Industry Co., Ltd.)
Resol type phenol resin PL-3224 (methanol-soluble resol type phenol resin, Mw = 800, solid content 70%, Gunei Chemical Industry Co., Ltd.)
≪Novolak type phenolic resin≫
-Novolak type phenol resin PS-1317 (Novolak type phenol resin, Mw = 6,560, solid content 100%, manufactured by Gunei Chemical Industry Co., Ltd.)
-Novolak type phenol resin PSK-2320 (Novolak type phenol resin, Mw = 5,650, solid content 100%, Gunei Chemical Industry Co., Ltd.)
-Novolak type phenol resin PSM-4324 (Novolak type phenol resin, Mw = 1,690, solid content 100%, hydroxyl group equivalent 107, manufactured by Gunei Chemical Industry Co., Ltd.)
・ Novolak type phenol resin Nd100 (Novolak type phenol resin, Mw = 1,140, solid content 100%, Gunei Chemical Industry Co., Ltd.)
-Novolak type phenol resin PSM-4271 (Novolak type phenol resin, Mw = 870, solid content 100%)
≪Other resins≫
Epoxy resin EOCN-1020-70 (ortho-cresol novolac type epoxy resin, epoxy equivalent 199, Mw = 1,900, solid content 100%)
<< Inorganic filler >>
Silica: Spherical fused silica RS-30, average particle size 80 μm, manufactured by Tokai Mineral Co., Ltd. << Other Components >>
-Curing catalyst: calcium hydroxide (manufactured by Ari Kogyo Co., Ltd.) (curing catalyst for resol-type phenol resin PS-4122B)
-Curing accelerator: triphenylphosphine (manufactured by Hokko Chemical Industry Co., Ltd.) (curing accelerator for epoxy resin EOCN-1020-70)
・ Colorant (carbon black # 40, manufactured by Mitsubishi Chemical)
・ Stress relaxation agent (KR-272, manufactured by Shin-Etsu Chemical Co., Ltd.)
・ Release agent (zinc stearate: Adeka)
・ Release agent (Carnauba wax # 1: Nippon Wax Co., Ltd.)
-Silane coupling agent (3-aminopropyltrimethoxysilane: KBE-903, manufactured by Shin-Etsu Chemical Co., Ltd.)
-Silane coupling agent (3-glycidoxypropyltriethoxysilane: KBE-403, manufactured by Shin-Etsu Chemical Co., Ltd.).
<< Resin solid content test method >>
For the mass of each phenol resin contained in the resin composition, the mass of the phenol resin itself containing no solvent is adopted as the mass of the solid content. A method for calculating the mass of the solid content in the phenol resin will be described. An aluminum petri dish having an inner diameter of 50 mm and a height of 15 mm, which had been weighed in advance, was precisely weighed, 1.5 g of the target resin was precisely weighed, heat-treated in a thermostat at 135 ° C. for 60 minutes, and then left to cool in a desiccator. This mass was measured, and the resin solid content was calculated according to the following (formula 5).
Resin solid content (%) = 100 × (M2-M0) / (M1) ... (Formula 5)
Here, (M0) represents the mass of the aluminum petri dish that has been weighed, (M1) represents the mass of the resin put in the aluminum petri dish, and (M2) represents the mass of the aluminum petri dish after the heat treatment and the resin component.

(Example 1)
First, as the resin composition of Example 1, based on the composition shown in Table 1 below, hydroxylation was performed as a curing catalyst for the resol type phenol resin PS-4122B, the novolac type phenol resin PSM-4324, and the resol type phenol resin PS-4122B. Calcium, silica as an inorganic filler, and zinc stearate, carbon black, and 3-aminopropyltrimethoxysilane as other raw materials were placed in a vinyl bag and shaken to perform a premix to obtain a mixture. .. The mixture was kneaded with a twin-screw roll at 95 ° C. for 5 minutes, cooled to room temperature, and then crushed with a crusher equipped with a screen having a diameter of 4 mm to obtain a mixed resin composition of particles and powder. ..

(Example 2)
The resin composition of Example 2 was prepared by replacing the resin composition of Example 1 with a resol type phenol resin PL-2211 having a different molecular weight.

(Example 3)
The resin composition of Example 3 was prepared by changing the resin composition of Example 1 to a novolak type phenol resin PSK-2320 having a different molecular weight.

(Example 4)
The resin composition of Example 4 was prepared by changing the resin composition of Example 3 to a novolac type phenol resin Nd100 having a different molecular weight.

(Example 5)
The resin composition of Example 5 was produced by changing the compounding ratio of the resol type phenol resin and the novolac type phenol resin from the resin composition of Example 4.

(Example 6)
A resin composition of Example 6 was prepared by replacing the resin composition of Example 5 with a novolac type phenol resin PSM-4324 having different molecular weights.

(Example 7)
The resin composition of Example 7 was produced from the resin composition of Example 4 by increasing the blending ratio of the inorganic filler.

(Example 8)
The resin composition of Example 8 was produced from the resin composition of Example 3 by reducing the compounding ratio of the inorganic filler.

(Example 9)
A stress relaxation agent was added to the resin composition of Example 4 to prepare the resin composition of Example 9.

(Example 10)
A resin composition of Example 10 was prepared by changing the resin composition of Example 1 to a resol type phenol resin PL-3224 having a different molecular weight.

(Example 11)
The resin composition of Example 11 was prepared by replacing the resin composition of Example 1 with a novolac type phenol resin PSM-4271 having a different molecular weight.

(Example 12)
The resin composition of Example 12 was prepared by replacing the resin composition of Example 1 with a novolac-type phenol resin PS-1317 having a different molecular weight.

(Example 13)
The novolak type phenolic resin was removed from the resin composition of Example 1 to prepare a resin composition of Example 13.

(Example 14)
The resin composition of Example 14 was produced by changing the compounding ratio of the resol type phenol resin and the novolac type phenol resin from the resin composition of Example 1.

(Example 15)
The resin composition of Example 15 was produced by increasing the blending ratio of the inorganic filler from the resin composition of Example 1.

(Comparative Example 1)
Based on the composition shown in Table 1 below, novolac type phenol resin PSM-4324, epoxy resin EOCN-1020-70, silica, carnauba wax, carbon black, and 3-glycidoxypropyltriethoxysilane were put into a vinyl bag. Then, the mixture was shaken for premixing to obtain a mixture. The mixture was kneaded with a twin-screw roll at 95 ° C. for 5 minutes. Triphenylphosphine was added as a curing accelerator for the epoxy resin EOCN-1020-70 to the sheet-shaped resin composition on the way on the biaxial roll, and the mixture was further kneaded with the biaxial roll heated to 95 ° C for 5 minutes, and then at room temperature. After cooling to, it was crushed by a crusher equipped with a screen having a diameter of 4 mm to obtain a mixed resin composition of particles and powder.

次いで、上記表１に示された実施例１〜１５、及び比較例１及び２の樹脂組成物の物性を評価した。 (Comparative example 2)
A resin composition of Comparative Example 2 was prepared from the resin composition of Example 1 by reducing the compounding ratio of the inorganic filler.

Next, the physical properties of the resin compositions of Examples 1 to 15 and Comparative Examples 1 and 2 shown in Table 1 above were evaluated.

[Molecular weight of phenol resin]
The molecular weight (Mw) of the phenol resin was measured by using the following GPC measuring device and column and polystyrene as a standard substance.
GPC measuring device: Tosoh Corporation HPLC8320GPC
Column: TSKgel G3000HXL + G2000HKL + G2000HKL (manufactured by Tosoh Corporation)
[Thin wall fluidity]
Regarding the resin compositions of Examples and Comparative Examples, a transfer provided with a flow path of 0.10 mm in thickness, 5.00 mm in width and 70 mm in length set in a 12-ton transfer molding press TFP12-16 (manufactured by Towa Seiki). The molding die was heated to 175 ° C. to obtain a flaky resin composition. After pouring 10.0 g of the resin composition into the pot of the apparatus, pressurization is performed at a plunger pressure of 2.9 MPa or 5.9 MPa. The resin composition was removed from the mold 120 seconds after the start of pressurization, the length of the flaky resin composition at this time was read, and this value was taken as the value of the thin-wall fluidity.

[Fluidity retention due to aging: Spiral flow retention]
A 12 ton transfer molding press TFP12-16 (manufactured by Towa Seiki Co., Ltd.) was set to a mold for spiral flow measurement conforming to EIMS T901 at 175 ° C., and 20.0 g of the resin composition was put into the pot of the apparatus, and then the plunger pressure was applied. Pressurize at 2.9 MPa. The resin composition was released from the mold 120 seconds after the start of pressurization, the length of the spiral resin composition at this time was read, and this value was taken as the value of spiral flow.

Regarding the spiral flow, the value of the spiral flow after the resin composition was manufactured and after the resin composition was stored at 5 ° C. and 25 ° C. for 336 hours, 672 hours, 1344 hours, 2016 hours, and 2688 hours was measured. The spiral flow retention rate was calculated according to the following (formula 1).
Spiral flow retention rate (%) = 100 × (X2) / (X1) (Equation 1)
Here, (X1) is a spiral flow measurement value of the resin composition, and (X2) is a spiral flow value of the resin composition after a specified time at a resin composition storage temperature of 5 ° C. or 25 ° C.

[Bending strength]
Bending strength measurement of 100 mm length, 10 mm width, and 4 mm thickness by molding the resin composition of each example and each comparative example by transfer molding for 3 minutes at 175 ° C. according to JIS K 6911 (1995 version). A test piece (molded product) was molded. This test piece was heat-treated at 175 ° C. for 4 hours, cooled to room temperature, and then measured for flexural strength using Strograph V10-C (manufactured by Toyo Seiki). The crosshead speed during bending strength measurement was set to 2 mm / min.

[Bending strength (ATF resistance test)]
Regarding the bending strength measurement test piece produced by the same method as the above-mentioned [bending strength], the bending strength after immersing the test piece in ATF (manufactured by Toyota Motor Corporation, Autofluid type T-IV) at 150 ° C. for 2000 hours was measured. It was measured.

[Bending strength (ATF resistance test)]
The bending strength retention rate of the test piece after immersion in ATF at 150 ° C. for 2000 hours was calculated according to the following (formula 2).
Bending strength retention rate (%) = 100 × (S2) / (S1) (Equation 2)
Here, (S1) is the bending strength before soaking in ATF, and (S2) is the bending strength after soaking in ATF at 150 ° C. for 2000 hours.

表１及び表２に示す結果より、以下のことが確認できる。 The weight (W1) and the volume (V1) of the test piece for measuring bending strength produced by the same method as the above-mentioned [Bending strength] were measured after standing for 24 hours in a desiccator containing silica gel. This test piece was immersed in ATF at 150 ° C., and the weight (W2) and volume (V2) were measured every 500 hours, 1000 hours, and 2000 hours, and the following (formula 3) and (formula 4) were obtained. The weight change rate and the volume change rate were measured in accordance with the above.
ATF resistance weight change rate (%) = 100 × (W2-W1) / W1 ... (Formula 3)
ATF volume change resistance (%) = 100 × (V2-V1) / V1 ... (Formula 4)
In Table 2 below, the thin-wall fluidity of each of the molded products of Examples 1 to 14 and Comparative Examples 1 and 2, spiral flow retention rate with time, bending strength, and ATF test (bending strength, bending strength The results of retention rate, weight change rate, volume change rate) are shown.

The following can be confirmed from the results shown in Table 1 and Table 2.

  Comparing Example 1 and Comparative Example 2, in Example 1, the content of the inorganic filler is 78.66% by mass of the entire resin composition, whereas in Comparative Example 2, it is 23.94% by mass. .. As a result, a large difference appeared in the bending strength of the molded product between Example 1 and Comparative Example 2. In Example 1, the bending strength of the molded product was 184 MPa, whereas in Comparative Example 2, it was 58 MPa, and it was confirmed that the molded product of Example 1 containing a large amount of the inorganic filler had a higher bending strength. It was

  Further, comparing Example 8 and Comparative Example 2, the content of the inorganic filler in Example 8 is 32.26% by mass of the resin composition, whereas in Comparative Example 2 is 23.94% by mass. is there. As a result, in Example 8, the bending strength of the molded product was 115 MPa, which was higher than 110 MPa, which is the preferred bending strength for the molded product, whereas in Comparative Example 2, it was 58 MPa. Therefore, it was confirmed that when the content of the inorganic filler is 30% by mass or more of the resin composition, a molded product having high bending strength can be obtained.

  By comparing the molded products of Examples 1, 2, and 10, the molded products of Examples 1 and 2 in which the weight average molecular weight of the resol-type phenol resin is in the range of 1,800 to 8,500 are the same as those of Example 10. It was confirmed that the bending strength was higher than that of the molded product. The flexural strength of the molded articles of Examples 1 and 2 was 110 MPa or more, whereas the flexural strength of the molded articles of Example 10 was less than 110 MPa.

  Comparing the resin compositions of Examples 1 and 13, the resin composition of Example 1 further containing a novolac type phenolic resin has thin flowability and spiral flow retention due to aging, and contains only resol type phenolic resin. It was confirmed that it was higher than that of the molded product of Example 13.

  Comparing the resin compositions of Examples 3 and 4, the resin composition of Example 4 containing a novolac-type phenolic resin having a small weight average molecular weight has a thin-wall fluidity and a spiral flow retention rate due to aging. It was confirmed that the cost was higher than that of the resin composition.

  By comparing the molded products of Examples 5, 6, and 14, the larger the mass ratio of the resole-type phenol resin to the novolak-type resin, the higher the molded product bending strength and the ATF test bending strength, and the ATF test bending strength retention. It was confirmed that the rate was high and the rate of change in the ATF resistance test weight was low.

  By comparing the resin compositions of Examples 7, 8, 15 and Comparative Example 2, it was confirmed that the larger the mass ratio of the phenol resin to the inorganic filler, the higher the thin-wall fluidity and the fluidity immediately after the production. .. When the mass ratio of the phenol resin to the inorganic filler is too large like the resin composition of Comparative Example 2 (phenol resin / inorganic filler = 75/25), the bending strength of the molded product, the bending strength of the ATF resistance test, and It was confirmed that the flexural strength retention rate in the ATF resistance test was low.

  Moreover, by comparing the molded products of Examples 1 to 15 and Comparative Example 2 with the resin composition of Comparative Example 1, the resin compositions of Examples 1 to 15 and Comparative Example 2 containing the resole resin were It was confirmed that the spiral flow retention rate with time was higher than that of the resin composition of Comparative Example 1 containing no resin. The resin compositions of Examples 1 to 15 and Comparative Example 2 have a spiral flow retention rate of 50% or more and less than 150% with respect to the resin composition immediately after production, after being stored at 25 ° C. for 2016 hours. there were.

  INDUSTRIAL APPLICABILITY The present invention can be used as a resin composition used for a magnet fixing material, a consumer part, an electric / electronic part, an automobile part and the like, and a molded article.

100 rotor 110 rotor core 120 magnet 130 slot

Claims (10)

A resin composition for fixing a magnet inside a slot provided in a rotor core,
Contains phenolic resin and inorganic filler,
As the phenolic resin, at least including a resol type phenolic resin,
A resin composition in which the content of the inorganic filler is 30% by mass or more based on the total amount of the phenol resin and the inorganic filler.   The resin composition according to claim 1, further comprising a novolac type phenol resin as the phenol resin.   The resin composition according to claim 2, wherein the mass ratio of the resol-type phenol resin to the novolac-type phenol resin is 95/5 to 5/95.   The resin composition according to any one of claims 1 to 3, wherein the resol-type phenol resin has a weight average molecular weight of 1,800 to 8,500.   The resin composition according to claim 2 or 3, wherein the novolac-type phenol resin has a weight average molecular weight of 800 to 7,000.   The resin composition according to any one of claims 1 to 5, wherein a mass ratio of the phenol resin to the inorganic filler is 5/95 to 70/30.   The resin composition according to any one of claims 1 to 6, wherein the inorganic filler is silica.   The resin composition according to claim 1, which is in the form of powder, granules, granules, or tablets.   The rate of change between the spiral flow measured immediately after demolding the resin composition from the mold and the spiral flow after the same resin composition is stored at 25 ° C. for 2000 hours is 50% or more and less than 150%. The resin composition according to any one of claims 1 to 8.   A rotor core formed by fixing a magnet with the resin composition according to claim 1.

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