Resin composition for use as molding material

Abstract

The present invention relates to a resin composition for use as a molding material, and a vehicle component molded using same, the resin composition comprising an epoxy resin, a curing agent, a filler, and an adhesion promoter including a melamine-based derivative, and, as a molding material for fixing a permanent magnet in a rotor, having an adhesive force of 4 kgf or more relative to the permanent magnet.

Description

Resin composition for molding materials

[0001] The present invention relates to a resin composition for a molding material and a vehicle part molded using the same.

[0002]

[0003] Rotors, a key component of automotive motors, come in a variety of shapes, but those with embedded magnets are the most common. These rotors are manufactured by laminating thin electrical steel sheets, with embedded magnets. Motors utilizing these rotors are called interior permanent magnet motors (IPMs). Because IPM motors generate both magnet-driven torque and reluctance torque, they are widely used in electric vehicle drive motors.

[0004] Methods for fixing a magnet inserted into a motor rotor to the rotor include using an adhesive, molding the magnet through transfer molding while the magnet is inserted into the rotor, or fixing it by injecting a liquid resin. For example, Japanese Patent Application Laid-Open No. 7-53792 discloses an epoxy composition for fixing a magnet.

[0005] These resin compositions for molding materials regulate the spacing between magnets within the rotor so that they are positioned at regular intervals, and secure the magnets so that they do not fall out. However, when a conventional epoxy resin composition is used to secure the magnets within the rotor, the fixing function is possible under normal circumstances, but in cases where a high level of vibration resistance is required, such as when the rotational speed increases due to high-speed driving or when the vibration experienced by the rotor increases due to the external driving environment, there is a problem in that the thermosetting resin is pushed to one side or cracks and delamination occur, causing the magnets to fall out or be damaged. Therefore, there is a need for the development of a resin composition for molding materials with excellent adhesive strength and vibration resistance.

[0006]

[0007] The present invention provides a resin composition for a molding material having excellent adhesive strength and vibration resistance. The present invention also provides a vehicle part molded using the resin composition for a molding material.

[0008]

[0009] The present invention provides a resin composition for a molding material comprising an epoxy resin, a curing agent, a filler, and an adhesion promoter including a melamine derivative, and fixing a permanent magnet in a rotor, wherein the resin composition has an adhesion force with the permanent magnet of 4 kgf or more.

[0010]

[0011] The present invention provides a resin composition for molding materials with excellent adhesive strength and vibration resistance. The resin composition for molding materials according to the present invention can be used as a molding material for vehicle parts, and due to its excellent adhesive strength with permanent magnets, can be used for fixing permanent magnets to a motor rotor.

[0012] The resin composition for a molding material according to the present invention has excellent adhesion and fixing strength with a magnetic permanent magnet, thereby preventing the permanent magnet from detaching even under high-speed rotation, and as a result, provides excellent vibration resistance, and thus can be applied to a motor requiring a high level of vibration resistance.

[0013]

[0014] The present invention will be described in detail below. However, the scope of the present invention is not limited solely to the details described below, and each component may be modified or selectively mixed as needed. Therefore, it should be understood that all modifications, equivalents, and alternatives included within the spirit and technical scope of the present invention are encompassed.

[0015] As used herein, “viscosity” is measured by conventional methods known in the art, and can be measured, for example, using a Brookfield viscometer. “Particle size (D 50 )” is measured by a conventional method known in the art, and can be measured, for example, by laser light scattering (LLS).

[0016]

[0017] <Resin composition for molding material>

[0018] The resin composition for a molding material of the present invention comprises an epoxy resin, a curing agent, a filler, and an adhesion promoter, and when applied as a molding material for fixing a permanent magnet in a rotor, the adhesive force with the permanent magnet is 4 kgf or more, for example, 4 to 20 kgf, or as another example, 4.1 to 10 kgf. Therefore, when the resin composition for a molding material according to the present invention is applied for the purpose of fixing a magnetic permanent magnet in a motor rotor, the permanent magnet is fixed even under high-speed rotation, thereby preventing detachment, and as a result, excellent vibration resistance is provided, so that it can be applied to a motor that requires a high level of vibration resistance. Therefore, in cases where a high level of vibration resistance is required, such as when the rotational speed increases due to high-speed driving or when the vibration experienced by the rotor increases due to the external driving environment, the resin composition for a molding material of the present invention can be used to fix a magnetic permanent magnet in a motor rotor, thereby preventing the phenomenon of the magnet being detached.

[0019]

[0020] epoxy resin

[0021] In the present invention, epoxy resin is used as a main resin, and by reacting with a curing agent and curing, a three-dimensional network structure is formed, thereby imparting strong and solid adhesion properties and heat resistance to an adherend.

[0022] As the epoxy resin, an epoxy resin commonly used in the relevant technical field can be used, and for example, one containing two or more epoxy groups in the molecular structure can be used. Non-limiting examples of epoxy resins that can be used include bisphenol A type epoxy resin, alicyclic epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, non-condensed ring type polycyclic structure epoxy resin, bisphenol fluorene modified epoxy, etc., and one or more of these can be included. For example, the epoxy resin can include a formaldehyde polymer with (chloromethyl)oxirane and 2-methylphenol.

[0023] The epoxy resin may be one having an epoxy equivalent weight (EEW) of 100 to 300 g / eq, for example, 180 to 230 g / eq, and a viscosity (150°C) of 300 to 600 cps, for example, 400 to 500 cps. An epoxy resin satisfying the above-described properties has relatively low viscosity characteristics, so that even when a high content of filler is included, flowability can be secured and mixing is easy.

[0024] Based on the total weight of the resin composition for the molding material, the content of the epoxy resin may be 5 to 30 wt%, for example, 5 to 20 wt%. If the content of the epoxy resin is less than the above-mentioned range, adhesion, flowability, and moldability may be reduced, and if it exceeds the above-mentioned range, unreacted epoxy resin may remain, resulting in a reduced degree of curing, which may result in poor reliability of the molding material, and a relative decrease in the filler content may result in a reduction in the strength of the molding material, which may result in a reduction in durability.

[0025]

[0026] hardener

[0027] The resin composition for molding material according to the present invention includes a curing agent. The curing agent reacts with the epoxy resin to promote curing of the composition, thereby improving adhesion.

[0028] The curing agent may be any curing agent known in the art that undergoes a curing reaction with an epoxy resin. For example, the curing agent may be a phenol-based compound having two or more phenolic hydroxyl groups in one molecule. For example, the curing agent may include at least one selected from the group consisting of a phenol novolac resin, a cresol novolac resin, a phenol aralkyl resin, and a polyfunctional phenol compound. For example, the curing agent may include a phenol polymer with formaldehyde.

[0029] The above curing agent may be one having a hydroxyl equivalent of 50 to 200 g / eq, for example, 90 to 120 g / eq, and a viscosity (150°C) of 0.1 to 20 poise, for example, 1 to 5 poise. If the hydroxyl equivalent of the curing agent exceeds the above-mentioned range, the glass transition temperature may be lowered, and if the viscosity exceeds the above-mentioned range, the mixing degree and filling property of the epoxy cured product may be reduced.

[0030] Based on the total weight of the resin composition for molding material, the content of the curing agent may be 1 to 20 wt%, for example, 1 to 10 wt%. If the content of the curing agent is less than the above-mentioned range, curability and moldability may be reduced, and if it exceeds the above-mentioned range, the reliability of the molding material may be deteriorated and the strength may be reduced due to increased moisture absorption.

[0031]

[0032] filler

[0033] The resin composition for a molding material according to the present invention includes a filler. The filler serves to improve the strength and flowability of the resin composition for a molding material.

[0034] As the filler, any filler commonly used in the relevant technical field can be used without limitation. For example, inorganic fillers such as silica, silica nitride, alumina, aluminum nitride, and boron nitride can be used, and these can be used alone or in combination of two or more. The shape of the filler is not particularly limited, and both angular and spherical shapes can be used.

[0035] The maximum particle size of the above filler is not particularly limited and may be, for example, 5 to 300 μm, another example, 5 to 180 μm, and another example, 5 to 75 μm. The average particle size ( D50 ) may be 1 to 30 μm, for example 5 to 15 μm.

[0036] Based on the total weight of the resin composition for molding materials, the content of the filler may be 40 to 90 wt%, for example, 50 to 90 wt%. If the content of the filler is less than the above-mentioned range, the moisture absorption of the resin composition for molding materials may increase, which may lower the reliability of the molding materials, and the fixing force may be reduced due to a decrease in strength, which may cause breakage or detachment of the permanent magnet, and if it exceeds the above-mentioned range, the fluidity may be reduced, which may result in poor moldability.

[0037]

[0038] adhesion promoter

[0039] The resin composition for a molding material according to the present invention includes an adhesion promoter.

[0040] The resin composition for a molding material of the present invention uses a compound containing an amino group in the molecule as an adhesion promoter. The adhesion promoter exhibits excellent curing properties due to the amino group contained in the molecule, thereby improving the durability of the resin composition for a molding material containing the same, and can tightly fix a permanent magnet in a motor rotor by suppressing cracking and peeling even when exposed to high pressure such as high-speed rotational force. Therefore, the resin composition for a molding material of the present invention containing the adhesion promoter, when applied for the purpose of fixing a permanent magnet to a motor rotor, has excellent adhesion to the permanent magnet and vibration resistance, and can be applied to a motor requiring a high level of vibration resistance.

[0041] The above adhesion promoter may include a solid adhesion promoter, a liquid adhesion promoter, or a mixture thereof.

[0042] The above-mentioned solid adhesion promoter may include a melamine derivative. The melamine derivative may include a salt thereof with an organic or inorganic acid such as boric acid, cyanuric acid, phosphoric acid, or pyro / polyphosphoric acid. For example, at least one selected from the group consisting of melamine cyanurate (a salt of melamine and cyanuric acid), a salt of melamine and phosphoric acid (e.g., melamine-mono-phosphate), melamine pyrophosphate, and melamine polyphosphate may be used.

[0043] The above liquid adhesion promoter may include an amino silane. Examples of the amino silane that may be used include phenyl-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethocysilane, and the like.

[0044] For example, the amino silane may be a secondary or higher amino silane having two or more functional groups bonded to the amino group, for example, N-Phenyl-aminopropyltrimethoxy silane. In the case of a primary amino silane having one functional group in the amino group, the reactivity is high, and the curing speed is fast, which reduces the fluidity of the resin composition for a molding material containing it, which causes problems such as reduced filling properties and moldability. Specifically, when the fluidity of the resin composition for a molding material is reduced, the resin composition for a molding material is not sufficiently injected into the mold, which reduces the filling properties, and the moldability is reduced, which leads to a lack of sufficient wetting properties, which may cause a problem such as reduced adhesion. In this case, the resin composition for a molding material should have high adhesive strength when in contact with the surface of a permanent magnet, and when rotating at high speed, the fixing force should be improved to prevent the permanent magnet from being detached from the motor. However, if the reaction speed is high and curing occurs quickly, the resin composition for a molding material may not be fixed to the surface of the permanent magnet.

[0045] For example, the adhesion promoter may include a solid adhesion promoter containing an amino group and a liquid adhesion promoter containing an amino group. In this case, the adhesion between the metal rotor and the permanent magnet can be further enhanced, thereby providing a resin composition for a molding material having excellent vibration resistance.

[0046] The adhesion promoter may further include a melamine derivative, an amino silane, or a mixture thereof. For example, the adhesion promoter includes a melamine derivative. For example, the adhesion promoter includes a melamine derivative and an amino silane.

[0047] The mixing ratio of the above melamine derivative and the above amino silane may be a weight ratio of 1:0.5 to 5, for example, a weight ratio of 1:0.5 to 2. If the mixing ratio of the amino silane to the melamine derivative is less than the above-mentioned range, the adhesive strength with the steel sheet may decrease, and if it exceeds the above-mentioned range, the reaction speed may be affected, resulting in a decrease in fluidity.

[0048] Based on the total weight of the resin composition for molding materials, the content of the adhesion promoter may be 0.1 to 5 wt%, for example, 0.1 to 3 wt%. If the content of the adhesion promoter is less than the aforementioned range, the adhesion may not be sufficiently enhanced, and if it exceeds the aforementioned range, the curing reaction may be affected, resulting in reduced fluidity.

[0049]

[0050] additives

[0051] The resin composition for molding material according to the present invention may further include additives commonly used in the relevant technical field, such as a release agent, a colorant, a catalyst, and a flame retardant, as needed.

[0052] To improve the release property between the epoxy molding compound (EMC) and the external mold, long-chain fatty acids, metal salts of long-chain fatty acids, paraffin wax, carnauba wax, polyethylene wax, silicone oil, etc. can be used as release agents. In addition, additives such as colorants (e.g., carbon black, Bengala, etc.) for imparting color to the resin composition, catalysts (e.g., imidazole compounds, amine compounds, organic phosphine compounds, etc.) for improving the curing speed and workability, and flame retardants (e.g., metal hydroxides, etc.) can be further included.

[0053] The above additives may be added within a content range known in the relevant technical field, and for example, may be included in an amount of 0.01 to 10 wt%, respectively, based on the total weight of the resin composition for molding materials, but is not limited thereto.

[0054]

[0055] When the resin composition for a molding material of the present invention is applied as a molding material for fixing a permanent magnet in a rotor, the adhesive strength with the permanent magnet is 4 to 20 kgf, for example, 4 to 10 kgf. If the adhesive strength with the permanent magnet is less than the aforementioned range, when applied to a motor that is continuously exposed to a harsh environment that rotates at high speed and requires a high level of vibration resistance, cracks or delamination may occur in the molding material, causing the magnet to detach or break. If the adhesive strength exceeds the aforementioned range, adhesion with the mold may occur during the molding process, which may reduce workability.

[0056] When the resin composition for a molding material of the present invention is applied as a molding material for fixing a permanent magnet in a rotor, the permanent magnet has a detachment force of 60 kgf or more, for example, 60 to 100 kgf. If the detachment force of the permanent magnet is less than the aforementioned range, when applied to a motor requiring a high level of vibration resistance, cracks or delamination may occur in the molding material, causing the magnet to detach or break, which may result in a deterioration in motor performance and durability.

[0057]

[0058] <Vehicle Parts>

[0059] The present invention provides a molded vehicle component using the aforementioned resin composition for molding materials. For example, the aforementioned resin composition for molding materials can be used as a molding material to secure and seal components within vehicle components requiring excellent vibration resistance, heat resistance, dimensional stability, and deformation resistance.

[0060] For example, a permanent magnet can be positioned in a hollow space formed within a rotor of a motor, and the resin composition for molding material of the present invention can be filled between the hollow space and the permanent magnet to fix the permanent magnet within the rotor. The resin composition for molding material according to the present invention has excellent adhesion to the permanent magnet and vibration resistance, so that the permanent magnet within the rotor can be fixed without distortion even in harsh environments of high-speed rotation, and thus can be applied to motors that require a high level of vibration resistance.

[0061]

[0062] Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended only to aid understanding of the present invention and are not intended to limit the scope of the present invention in any way.

[0063]

[0064] [Experimental Example 1-12]

[0065] According to the following Tables 1 and 2, each component was mixed to prepare a resin composition for a molding material of each experimental example. Using a transfer molding press (175 ℃, 40 kgf / ㎠), the resin composition for a molding material of each experimental example was molded into a cylindrical shape (upper diameter * lower diameter * height = 4Φ * 5Φ * 5㎜) on a permanent magnet for a rotor core to prepare a specimen for measuring adhesive force, and a shear stress (speed 300 ㎛ / s, height 5 ㎛) was applied to the molding material of each specimen using a shear tool of a die shear tester, and the force when the molding material is detached from the permanent magnet was measured to evaluate the adhesive force with the permanent magnet, and the results are shown in the following Table 1.

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] Epoxy resin: formaldehyde polymer with (chloromethyl)oxirane and 2-methylphenol (Cas No. 29690-82-2, epoxy equivalent 203 g / eq)

[0072] Curing agent: phenol resin, phenol polymer with formaldehyde (Cas No. 9003-35-4, hydroxyl equivalent 107 g / eq)

[0073] Filler: Silica (D 50 9 ㎛)

[0074] Adhesion promoter 1: Melamine derivative (salt of melamine and cyanuric acid)

[0075] Adhesion promoter 2: Amino silane (N-phenyl-aminopropyltrimethoxy silane)

[0076] Adhesion promoter 3: methyltrimethoxysilane

[0077] Silane: 3-Glycidoxypropyl trimethoxysilane

[0078] Wax: Carnauba wax

[0079] Colorant: Carbon black

[0080] Flame retardant: magnesium hydroxide

[0081] Catalyst: 2-phenyl-4-methyl-5-hydroxymethylimidazole

[0082]

[0083] [Physical property evaluation]

[0084] The properties of the resin composition for molding material manufactured in each experimental example were measured as follows, and the results are shown in Tables 3 and 4 below.

[0085]

[0086] Spiral flow

[0087] Flowability was measured using a transfer molding press (175°C, 70 kgf / cm2) using an evaluation mold according to EMMI-1-66. It is desirable to secure a flowability of 25 inches or more so that the resin composition for molding material can flow to the slot portion where the magnet is inserted in the rotor and fill the space.

[0088]

[0089] Gel time

[0090] After setting the temperature (175°C) to the same as the mold press using a hot plate, the time from the melting point of each specimen to the gelation point was measured. Since sufficient time is required for the resin composition for molding materials to completely fill the slot area where the magnets are inserted in the rotor, it is desirable to secure a gel time of 15 seconds or more.

[0091]

[0092] delamination

[0093] After applying the resin composition for molding material of each experimental example on a silver-plated copper lead frame, the TO-247 package was formed by curing at 175°C for 120 seconds using an MGP (Multi-gang pot) facility. The molded package was post-cured, and the number and area of ​​internal delaminations were observed using SAT (Scanning Acoustic Tomography), and evaluated according to the following criteria.

[0094] Excellent (◎): No peeling

[0095] Good (○): Some peeling occurred (less than 10% of the area)

[0096] Normal (△): Number of peels: 2 or less

[0097] Thirteen (X): Number of peels exceeds 2

[0098]

[0099] magnetic separation force

[0100] After molding the slots in which the magnets were inserted within the rotor using the resin composition for molding materials of each experimental example, the maximum load (kgf) applied until the magnets were removed from the slots was measured using a UTM device. A maximum load of 60 kgf or more was judged as acceptable.

[0101]

[0102] fracture

[0103] Using the resin composition for molding material of each experimental example, a slot in which a magnet is inserted in a rotor is molded, and vibration is applied for 10 G x 60 Hz x 1 hour using a vibration tester. Then, the number and area of ​​cracks occurring in the area where the resin composition for molding material was molded are observed, and evaluated according to the following criteria.

[0104] [metewand]

[0105] Excellent (◎): No breakage

[0106] Good (○): No breakage, some cracks (less than 5% of the area)

[0107] Normal (△): No breakage, some cracks (over 5% of the area)

[0108] Thirteen (X): Breakage occurs

[0109]

[0110] glass transition temperature

[0111] For each experimental example, molding resin compositions were used to mold specimens of the same size, and the temperature was measured from room temperature to 300°C at a heating rate of 10°C / min using a Thermo-mechanical Analyzer (TMA), and the glass transition temperature was obtained using the onset point technique. Considering the heat generated during high-speed rotation of the rotor, it is desirable to secure a glass transition temperature of 170°C or higher, and in this case, cracking of the epoxy molding compound (EMC) can be prevented by minimizing shrinkage / expansion due to temperature rise and cooling processes.

[0112]

[0113] Coefficient of linear expansion

[0114] Using the resin composition for molding material of each experimental example, specimens of the same size were molded, and using a TMA (Thermomechanical Analyzer), the linear expansion coefficient α1 below the glass transition temperature and the linear expansion coefficient α2 above the glass transition temperature were measured. When a1 is 30 ppm / ℃ or less and a2 is 80 ppm / ℃ or less, peeling and cracking due to shrinkage / expansion can be effectively prevented.

[0115]

[0116]

[0117]

[0118]

[0119]

[0120] As shown in Tables 3 and 4 above, the resin composition for molding materials of Experimental Examples 1-9 according to the present invention exhibited excellent adhesion to permanent magnets and thus exhibited excellent physical properties in all measured items. In particular, the resin composition for molding materials of Experimental Examples 1-9 exhibited excellent physical properties in a peeling evaluation for a silver-plated copper lead frame, and thus it was confirmed that the adhesion to permanent magnets was also excellent, so that peeling did not occur, and it was confirmed that the magnet detachment force and breakage characteristics were also excellent.

[0121] On the other hand, the resin composition for molding material of Experimental Examples 10-12, which does not contain a melamine derivative and whose adhesion to a permanent magnet does not meet the range according to the present invention, exhibited inferior physical properties across all measured items.

[0122]

[0123] The present invention provides a resin composition for a molding material having excellent adhesion and vibration resistance.

Claims

1. Contains an adhesion promoter including an epoxy resin, a hardener, a filler, and a melamine derivative, A resin composition for a molding material that fixes a permanent magnet in a rotor, the resin composition having an adhesive force with the permanent magnet of 4 kgf or more.

2. In the first paragraph, the epoxy resin has an epoxy equivalent weight (EEW) of 100 to 300 g / eq and a viscosity (150°C) of 300 to 600 cps, A resin composition for a molding material, wherein the hydroxyl equivalent of the above-mentioned curing agent is 50 to 200 g / eq and the viscosity (150°C) is 0.1 to 20 poise.

3. A resin composition for a molding material in the first paragraph, wherein the melamine derivative comprises at least one selected from the group consisting of a salt of melamine and cyanuric acid, a salt of melamine and phosphoric acid, melamine pyrophosphate, and melamine polyphosphate.

4. A resin composition for a molding material according to claim 1, wherein the adhesion promoter further comprises at least one amino silane selected from the group consisting of phenyl-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-2-(aminoethyl)-3-aminopropylmethydimethocysilane.

5. A resin composition for a molding material in the fourth paragraph, wherein the mixing ratio of the melamine derivative and the amino silane is 1:0.5 to 5 by weight.

6. A resin composition for a molding material, comprising 5 to 30 wt% of the epoxy resin, 1 to 20 wt% of the curing agent, 40 to 90 wt% of the filler, and 0.1 to 5 wt% of the adhesion promoter, based on the total weight of the resin composition for a molding material in paragraph 1.

7. A resin composition for a molding material in accordance with paragraph 1, wherein the detachment force of the permanent magnet is 60 kgf or more.

8. A vehicle part molded using a resin composition for molding material according to any one of claims 1 to 7.

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