Compounds and tablets

Abstract

Provided is a compound comprising a magnet powder, a thermosetting resin, and a wax. The magnet powder includes a Sm-Fe-N permanent magnet. The sum of the mass of the magnet powder and the mass of the thermosetting resin is represented by M1. The mass of the wax is represented by M2. (M2 / M1)×100 is 2 to 10. The compound is used as a raw ingredient for an anisotropic bond magnet having excellent residual magnetic flux density and mechanical strength. The amount of wax included in the anisotropic bond magnet may be 0.0% by mass to 0.1% by mass.

Description

[Technical Field]

[0001] This disclosure relates to compounds, tablets, molded articles, and anisotropic bonded magnets. [Background technology]

[0002] Sm-Fe-N permanent magnets (samarium-iron-nitrogen permanent magnets) can be manufactured from cheaper raw materials compared to other rare-earth magnets such as Nd-Fe-B permanent magnets (neodymium-iron-boron permanent magnets), and possess excellent magnetic properties. However, the crystal structure of Sm-Fe-N permanent magnets is prone to degradation at high temperatures (approximately 500°C), making it difficult to manufacture sintered magnets from them. Therefore, Sm-Fe-N permanent magnets are used as raw materials for anisotropic bonded magnets, which can be manufactured by heating at low temperatures (thermal curing of the thermosetting resin mixed with the magnet powder) while maintaining the crystal structure.

[0003] Anisotropic bonded magnets are manufactured using a compound containing magnet powder (numerous magnet particles made up of permanent magnets) and a thermosetting resin as raw materials. In the manufacture of anisotropic bonded magnets, the compound is supplied into a mold. A molded body is formed from the compound by compressing it in the mold while applying a magnetic field generated by a coil to the compound in the mold. Each magnet particle (magnetic domain within each magnet particle) in the molded body is magnetized and oriented along the magnetic field. The molded body is demagnetized, hardened by heating, and then magnetized to obtain an anisotropic bonded magnet. The residual magnetic flux density (Br), one of the important magnetic properties of anisotropic bonded magnets, is improved by the orientation of the magnet powder in the molded body and by increasing the filling density of the magnet powder in the molded body.

[0004] In addition to the manufacturing methods described above, various other manufacturing methods using Sm-Fe-N permanent magnets are known. For example, Patent Document 1 discloses a method for producing a magnet molded body with high residual magnetic flux density by cold compaction molding of Sm-Fe-N magnet powder containing a metal binder (Zn and Cu, etc.) at high pressure (1 to 5 GPa). Patent Document 2 discloses a method for producing bonded magnets from a compound containing Sm-Fe-N magnet powder and a low-viscosity thermosetting resin. Patent Document 3 discloses a compound containing Sm-Fe-N magnet powder, epoxy resin, and wax as raw materials for bonded magnets. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-82175 [Patent Document 2] Japanese Patent Publication No. 2021-127515 [Patent Document 3] International Publication No. 2019 / 106813 [Patent Document 4] Japanese Patent Publication No. 2019-48948 [Overview of the project] [Problems that the invention aims to solve]

[0006] Magnetic powder made from Sm-Fe-N permanent magnets can exhibit anisotropy. That is, each magnetic particle (magnetic domain within each magnetic particle) constituting the magnetic powder made from Sm-Fe-N permanent magnets can have an easy magnetization axis (crystal axis) extending in one direction. Therefore, when the magnetic powder is made from Sm-Fe-N permanent magnets, during the compression process of a compound under an applied magnetic field, each magnetic particle in the compound rotates due to the magnetic field, and the easy magnetization axis of each magnetic particle (magnetic domain) is easily oriented along the direction of the magnetic field. As a result, an anisotropic bonded magnet with high residual magnetic flux density can be obtained. However, the higher the viscosity of the thermosetting resin in the compound, the more difficult it is for each magnetic particle in the compound to rotate due to the magnetic field, and the less difficult it is for the easy magnetization axis of each magnetic particle (magnetic domain) to be oriented along the direction of the magnetic field. Even when the viscosity of the thermosetting resin in the compound is high, using a pulsed magnetic field with high intensity will cause each magnetic particle in the compound to rotate due to the magnetic field. However, generating a pulsed magnetic field requires a large magnetic field generator. On the other hand, when using a static magnetic field (a continuous, constant magnetic field) generated by a small magnetic field generator, it is difficult to sufficiently orient the easy magnetization axis of each magnetic particle in the compound along the magnetic field.

[0007] When a compound contains wax in addition to magnetic powder and thermosetting resin, the lubricating properties of the wax allow each magnetic particle in the compound to rotate easily. However, unlike thermosetting resin (binder), the wax does not harden when heated and does not bind the magnetic particles together. Therefore, as the wax content in the compound increases, the mechanical strength of the molded body formed from the compound decreases, and the mechanical strength of the anisotropic bonded magnet also decreases. For example, mechanical strength can be rephrased as crushing strength or radial crushing strength.

[0008] One aspect of the present invention is to provide a compound used as a raw material for an anisotropic bonded magnet with excellent residual magnetic flux density and mechanical strength, a tablet containing the compound, a molded article manufactured from the compound, and an anisotropic bonded magnet with excellent residual magnetic flux density and mechanical strength. [Means for solving the problem]

[0009] For example, one aspect of the present invention relates to a compound described in any one of the following items [1] to [3], a tablet described in the following item [4], a molded article described in any one of the following items [5] to [7], and an anisotropic bonded magnet described in any one of the following items [8] to

[10] .

[0010] [1] A compound comprising magnetic powder, thermosetting resin, and wax, The magnetic powder contains Sm-Fe-N based permanent magnets. The sum of the mass of the magnetic powder and the mass of the thermosetting resin is represented as M1. The mass of the wax is represented as M2. (M2 / M1) × 100 is between 2 and 10, Used as a raw material for anisotropic bond magnets, Compound. [1] is rephrased as follows: [1'] [1'] comprising magnetic powder, thermosetting resin, and wax, The magnetic powder contains Sm-Fe-N permanent magnets. The sum of the mass of the magnetic powder and the mass of the thermosetting resin is represented as M1. The mass of the wax is represented as M2. For compounds where (M2 / M1)×100 is between 2 and 10, Application to raw materials for anisotropic bonded magnets.

[0011] [2] The thermosetting resin comprises at least one resin selected from the group consisting of epoxy resins, maleimide compounds, polyimides, polyamides, and polyamideimides. The compound described in [1].

[0012] [3] The wax contains montanic acid esters, The compound described in [1] or [2].

[0013] [4] A compound including any one of the items in [1] to [3], tablet.

[0014] [5] A molded article comprising magnetic powder and a thermosetting resin, The magnetic powder contains Sm-Fe-N permanent magnets. The thermosetting resin comprises at least one resin selected from the group consisting of maleimide compounds, polyimides, polyamides, and polyamideimides. The easy magnetization axis in each magnetic particle constituting the magnetic powder is oriented. Molded body.

[0015] [6] The wax content is 0.0% by mass or more and 0.1% by mass or less. [5] The molded body described above.

[0016] [7] The wax contains montanic acid esters, The molded body described in [6].

[0017] [8] An anisotropic bonded magnet comprising magnetic powder and a cured product of a thermosetting resin, The magnetic powder contains Sm-Fe-N permanent magnets. The thermosetting resin comprises at least one resin selected from the group consisting of maleimide compounds, polyimides, polyamides, and polyamideimides. The magnetization direction of each magnetic particle constituting the magnetic powder is oriented. Anisotropic bonded magnets.

[0018] [9] The wax content is 0.0% by mass or more and 0.1% by mass or less. An anisotropic bonded magnet as described in [8].

[0019]

[10] The wax contains montanic acid esters, An anisotropic bonded magnet as described in [9]. [Effects of the Invention]

[0020] According to one aspect of the present invention, a compound used as a raw material for an anisotropic bonded magnet having excellent residual magnetic flux density and mechanical strength, a tablet containing the compound, a molded article manufactured from the compound, and an anisotropic bonded magnet having excellent residual magnetic flux density and mechanical strength are provided. [Brief explanation of the drawing]

[0021] [Figure 1] Figures 1(a) and 1(b) are schematic cross-sectional views of a manufacturing apparatus used in a method for manufacturing a molded article and an anisotropic bonded magnet according to one embodiment of the present invention. The cross-sections shown in Figures 1(a) and 1(b) traverse a pair of punches, dies, a compound, and a pair of coils, and are parallel to the direction of pressure exerted by the pair of punches on the compound (pressure direction). [Figure 2] Figure 2 is a schematic cross-sectional view of a molded article (or anisotropic bonded magnet) according to one embodiment of the present invention. [Modes for carrying out the invention]

[0022] (Summary of the embodiment) Preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings, equivalent components are denoted by the same reference numerals. The present invention is not limited to the embodiments described below. X, Y, and Z shown in Figure 1(a), Figure 1(b), and Figure 2 represent three mutually orthogonal coordinate axes. The directions of the X, Y, and Z axes are common to Figure 1(a), Figure 1(b), and Figure 2.

[0023] The compound according to this embodiment comprises magnetic powder, a thermosetting resin, and a wax. The magnetic powder can be rephrased as a large number of magnetic particles made of permanent magnets. The magnetic powder includes Sm-Fe-N permanent magnets. The magnetic powder may consist only of Sm-Fe-N permanent magnets. For example, the compound may include at least one resin selected from the group consisting of epoxy resins, maleimide compounds, polyimides, polyamides, and polyamideimides as the thermosetting resin (e.g., a heat-resistant thermosetting resin). For example, the wax in the compound may include montanic acid ester. The sum of the mass of the magnetic powder and the mass of the thermosetting resin is expressed as M1. The mass of the wax is expressed as M2. (M2 / M1) × 100 is between 2 and 10. The compound is used as a raw material for anisotropic bonded magnets.

[0024] The tablet according to this embodiment contains the compound described above. The tablet may consist solely of the compound described above. The tablet, like the compound, is used as a raw material for anisotropic bonded magnets.

[0025] The molded body according to this embodiment is a work-in-process product of an anisotropic bonded magnet. In other words, the molded body is manufactured during the manufacturing process of the anisotropic bonded magnet. The molded body is manufactured from the compound described above. The molded body according to this embodiment corresponds to a molded body from which the wax has been removed by the molding process described later. The molded article according to this embodiment includes magnetic powder and a thermosetting resin. The magnetic powder in the molded article includes an Sm-Fe-N permanent magnet. The magnetic powder in the molded article may be the same as the magnetic powder in the compound. The thermosetting resin in the molded article may be the same as the thermosetting resin contained in the compound. For example, the molded article may contain at least one resin selected from the group consisting of epoxy resin, maleimide compound, polyimide, polyamide, and polyamideimide as the thermosetting resin (e.g., a heat-resistant thermosetting resin). Part or all of the thermosetting resin in the molded article may be uncured. Part or all of the thermosetting resin in the molded article may be semi-cured. Part or all of the thermosetting resin in the molded article may be cured. The wax content in the molded article may be 0.0% by mass or more and 0.1% by mass or less. The wax in the molded article may be the same as the wax contained in the compound. For example, the wax in the molded article may contain montanate ester. The molded article does not need to contain wax.

[0026] The anisotropic bonded magnet according to this embodiment includes magnetic powder and a cured product of a thermosetting resin. The magnetic powder in the anisotropic bonded magnet includes an Sm-Fe-N permanent magnet. The magnetic powder in the anisotropic bonded magnet may be the same as the magnetic powder in the compound. The thermosetting resin in the anisotropic bonded magnet may be the same as the thermosetting resin contained in the compound. For example, the anisotropic bonded magnet may include at least one resin selected from the group consisting of epoxy resin, maleimide compound, polyimide, polyamide, and polyamideimide as the thermosetting resin (e.g., a heat-resistant thermosetting resin). The wax content in the anisotropic bonded magnet may be 0.0% by mass or more and 0.1% by mass or less. The wax in the anisotropic bonded magnet may be the same as the wax contained in the compound. For example, the wax in the anisotropic bonded magnet may contain montanate ester. The anisotropic bonded magnet does not need to contain wax.

[0027] The easy magnetization axis in each magnetic particle (each magnetic domain within each magnetic particle) constituting the magnetic powder in the molded body is oriented along a predetermined direction (the direction of the magnetic field H, described later). Similarly, the easy magnetization axis in each magnetic particle (each magnetic domain within each magnetic particle) constituting the magnetic powder in the anisotropic bonded magnet is also oriented along a predetermined direction (the direction of the magnetic field H, described later). Since the anisotropic bonded magnet undergoes the magnetization process described later, the magnetization direction of each magnetic particle constituting the magnetic powder in the anisotropic bonded magnet is oriented along a predetermined direction (the direction of the magnetic field H described later). In other words, each magnetic particle constituting the magnetic powder in the anisotropic bonded magnet is magnetized in a predetermined direction (the direction of the magnetic field H described later). Therefore, the anisotropic bonded magnet as a whole is also magnetized in a predetermined direction (the direction of the magnetic field H described later).

[0028] Anisotropic bonded magnets are manufactured by the following manufacturing method using the compound described above. Anisotropic bonded magnets manufactured from the compound according to this embodiment can have high residual magnetic flux density and high mechanical strength (especially mechanical strength at high temperatures). For example, mechanical strength at high temperatures refers to the mechanical strength at 150°C. The reason why anisotropic bonded magnets manufactured from the compound described above have excellent residual magnetic flux density and mechanical strength is explained below in relation to the manufacturing method.

[0029] (manufacturing equipment) Figures 1(a) and 1(b) show schematic cross-sections of the manufacturing apparatus 10 (molding apparatus) used in the manufacturing method of anisotropic bonded magnets according to this embodiment.

[0030] The manufacturing apparatus 10 includes a pair of opposing punches (first punch p1 and second punch p2) and a cylindrical die d1 into which the pair of punches are inserted. A first opening is formed on the end face of die d1 facing the first punch p1, and the first punch p1 is inserted into the first opening. A second opening is formed on the end face of die d1 facing the second punch p2, and the second punch p2 is inserted into the second opening. A cavity (concave mold) is formed from the second punch p2 inserted into die d1 and die d1. The first punch p1 functions as a core (convex mold). In other words, a pair of opposing punches (first punch p1 and second punch p2) and a cylindrical die d1 into which the pair of punches are inserted constitute a set of molds.

[0031] Compound 2, the raw material for the anisotropic bonded magnet, is supplied into a cavity consisting of a second punch p2 and a die d1. (See Figure 1(a)). Compound 2 in the cavity is sandwiched between the first punch p1 and the second punch p2, and is pressurized and compressed by the first punch p1 and the second punch p2. (See Figure 1(b)). The direction of the pressure exerted on compound 2 by the first punch p1 and the second punch p2 (pressure direction) is parallel to the Z-axis. In this embodiment, "pressure acting on the compound in the mold" refers to the pressure exerted on compound 2 by the first punch p1 and the second punch p2. "Pressure acting on the compound in the mold" is referred to as molding pressure.

[0032] A clearance 6 is formed in the mold. For example, the clearance 6 is formed between the sides of the first punch p1 and the second punch p2 and the inner wall of the die d1. Due to the clearance 6, the sides of the first punch p1 and the second punch p2 slide easily against the inner wall of the die d1. As described later, some or all of the wax 4 in the compound 2 is discharged out of the mold (cavity) through the clearance 6 during the molding process. The width of the clearance 6 is sufficiently small that the magnetic powder and thermosetting resin in the compound 2 are not discharged out of the mold through the clearance 6. For example, the width of the clearance 6 may be less than the particle size of each magnetic particle constituting the magnetic powder. As long as the inside of the mold (cavity) communicates with the outside of the mold through the clearance 6, the position in the mold where the clearance 6 is formed is not limited.

[0033] The dimensions and shapes of the first punch p1, the second punch p2, and the die d1 are not limited. For example, the dimensions and shapes of the first punch p1, the second punch p2, and the die d1 may be changed according to the desired dimensions and shape of the molded body or anisotropic bonded magnet. The composition of the first punch p1, the second punch p2, and the die d1 is not limited. For example, the first punch p1, the second punch p2, and the die d1 may each be a metal having sufficient mechanical strength as a mold.

[0034] The manufacturing apparatus 10 includes a pair of coils (first coil c1 and second coil c2). The die d1 and the compound 2 inside the die d1 are placed between the pair of coils (first coil c1 and second coil c2). The first punch p1 and the second punch p2 do not penetrate the inside of each of the pair of coils (first coil c1 and second coil c2).

[0035] The manufacturing apparatus 10 further includes a power supply mechanism. The power supply mechanism is electrically connected to the first coil c1 and the second coil c2, respectively. The direction and absolute value of the first current generated in the first coil c1 and the direction and absolute value of the second current generated in the second coil c2 can be freely controlled by the power supply mechanism. The power supply mechanism is omitted in each figure.

[0036] A magnetic field H may be generated from the magnetic field generated in the first coil c1 and the magnetic field generated in the second coil c2, and this combined magnetic field H may be applied to the compound 2 in the die d1. Alternatively, the magnetic field H generated by only one of the coils, the first coil c1 and the second coil c2, may be applied to the compound 2 in the die d1. Details of the magnetic field H will be described later.

[0037] The central axes of the first coil c1 and the second coil c2 coincide with each other and are parallel to the X-axis. The magnetic field H generated by the first coil c1 and the second coil c2 is also parallel to the X-axis. The direction of the magnetic field H is perpendicular to the direction of pressure. In other words, a magnetic field H perpendicular to the direction of pressure is applied to the compound. However, the direction of the magnetic field H is not limited. The direction of the magnetic field H may be changed by changing the arrangement of the first coil c1 and the second coil c2. For example, the first punch p1 may penetrate the inside of the first coil c1, and the second punch p2 may penetrate the inside of the second coil c2, and the die d1 may be placed between the first coil c1 and the second coil c2, and the central axes of the first coil c1 and the second coil c2 may coincide with each other, and the central axes of the first coil c1 and the second coil c2 may be parallel to the direction of pressure. As a result, a magnetic field H parallel to the direction of pressure may be applied to the compound 2.

[0038] (Method for manufacturing anisotropic bonded magnets) The method for manufacturing an anisotropic bonded magnet according to this embodiment includes a supply step, a molding step, a cooling step, a demagnetization step, a thermosetting step, and a magnetization step. Details of each step will be described below.

[0039] <Supply process> In the supply process, compound 2 is supplied into the mold (cavity) described above. (See (a) in Figure 1.) Details of the magnetic powder will be described later. The temperature of the compound itself supplied into the mold may be room temperature. Compound 2 may be solid at room temperature. For example, compound 2 may be a powder. Instead of compound 2, tablets made of compound 2 may be supplied into the mold.

[0040] <Molding process> In the molding process, the compound 2 in the mold, heated to a molding temperature Tm, is compressed while a magnetic field H is applied. (See (b) in Figure 1.) Since the molding temperature Tm is above the dropping point of wax, the wax in the compound 2 is liquefied. Due to the lubricating properties of the liquefied wax, the magnetic particles slide easily against each other, each magnetized magnetic particle rotates easily due to the magnetic field H, and the easy magnetization axis of the magnetic domain in each magnetic particle is oriented along the magnetic field H. In other words, each magnetic particle 3 is oriented so that its magnetization direction m is approximately parallel to the magnetic field H. (See Figure 2.) If each magnetic particle 3 is a single crystal grain (single magnetic domain), the magnetization direction m of each magnetic particle 3 is the same as the direction in which the easy magnetization axis of each magnetic particle extends. Since the molding temperature Tm is below the thermosetting temperature of the thermosetting resin 5, the thermosetting of the thermosetting resin is suppressed during the molding process, and the rotation and orientation of each magnet particle 3 driven by the magnetic field H are not easily hindered by the thermosetting of the thermosetting resin 5. As the compound 2 is compressed, a molded body 2A is formed containing magnet powder and thermosetting resin (uncured material) oriented along the magnetic field H. The magnetization direction M of the entire molded body 2A before demagnetization is approximately parallel to the direction of the magnetic field H applied to the compound 2 during the molding process.

[0041] As described above, the lubricity of the wax during the molding process results in a molded body 2A with excellent orientation of the magnetic powder. The oriented state of the magnetic powder is maintained even after demagnetization and heat curing of the molded body 2A. Therefore, the anisotropic bonded magnet obtained by magnetizing the molded body after demagnetization and heat curing can have a high residual magnetic flux density due to the excellent orientation of the magnetic powder. Furthermore, the compression of compound 2 during the molding process (i.e., an increase in the filling rate of magnetic powder in the molded body 2A) increases the residual magnetic flux density of the anisotropic bonded magnet.

[0042] According to this embodiment, even if the viscosity of the thermosetting resin is high and the thermosetting resin hinders the rotation and orientation of the magnet particles, the lubricating properties of the liquefied wax allow each magnet particle to rotate and orient. Therefore, according to this embodiment, anisotropic bonded magnets can be manufactured using thermosetting resins that were previously difficult to use as raw materials for anisotropic bonded magnets (for example, high-viscosity, heat-resistant thermosetting resins). As a result, the anisotropic bonded magnets can have high mechanical strength at high temperatures. For example, the heat-resistant thermosetting resin may be at least one resin selected from the group consisting of epoxy resins, maleimide compounds, polyimides, polyamides, and polyamideimides. Details of the thermosetting resin will be described later.

[0043] As described above, the residual magnetic flux density of anisotropic bonded magnets increases due to the presence of wax. However, unlike thermosetting resins (binders), wax does not harden and does not bind the magnet particles together. Therefore, the residual wax in the molded body 2A reduces the mechanical strength of the molded body 2A. The residual wax from compound 2 in the anisotropic bonded magnets obtained from the molded body also reduces the mechanical strength of the anisotropic bonded magnets. However, during the molding process, compound 2 is compressed while the mold is heated at a molding temperature Tm that is above the dropping point of the wax. As a result, during the formation process of the molded body 2A (compression process of compound 2), some or all of the liquefied wax in the molded body 2A seeps out of the molded body 2A, and the wax is removed from the molded body 2A. Therefore, according to this embodiment, it is possible to suppress the decrease in the mechanical strength of anisotropic bonded magnets caused by wax, which contributes to the increase in the residual magnetic flux density of anisotropic bonded magnets. In other words, according to this embodiment, it is possible to achieve both high residual magnetic flux density and high mechanical strength.

[0044] During the molding process, the wax 4 removed from the molded body 2A is discharged out of the mold through the clearance 6 formed in the mold. (See (b) in Figure 1.) The molding temperature Tm is above the dropping point of the wax and below the thermosetting temperature of the thermosetting resin. Therefore, the viscosity of the wax at molding temperature Tm is lower than the viscosity of the thermosetting resin at molding temperature Tm, the wax is more fluid than the thermosetting resin at molding temperature Tm, and the wax and thermosetting resin are not very miscible at molding temperature Tm. As a result, the wax 4 is easily separated from the thermosetting resin during the molding process, and of the wax 4 and thermosetting resin, only the wax 4 is selectively removed from the molded body 2A, and only the wax 4 is selectively discharged out of the mold through the clearance 6. On the other hand, the thermosetting resin is difficult to remove from the molded body 2A during the molding process, and the thermosetting resin is difficult to discharge out of the mold through the clearance 6.

[0045] The dropping point of wax is the temperature at which wax liquefies upon heating. For example, the dropping point of wax is the temperature of the wax in a container with an opening of a predetermined inner diameter at the point when the wax liquefies upon heating and begins to drip from the opening. For example, the dropping point of wax may be measured according to JIS (Japanese Industrial Standards) K 2220, or ASTM (American Society for Testing and Materials) standards D-566 and D-2265.

[0046] The dropping point of the wax is a value that depends on the composition of the wax and is not limited. The thermosetting temperature of the thermosetting resin is a value that depends on the composition of the thermosetting resin and is not limited. The molding temperature Tm is a value that depends on the combination of wax and thermosetting resin and is not limited. For example, the molding temperature Tm may be 60°C or more and 150°C or less, preferably 70°C or more and 110°C or less, and more preferably 80°C or more and 100°C or less.

[0047] As described above, the sum of the mass of the magnet powder and the mass of the thermosetting resin is expressed as M1 (in g). The mass of the wax is expressed as M2 (in g). (M2 / M1) × 100 is between 2.0 and 10.0. When (M2 / M1) × 100 is 2.0 or greater, the lubricating properties of the wax 4 make it easy for each magnet particle 3 to rotate and for each magnet particle 3 to be oriented along the magnetic field H. As a result, the anisotropic bonded magnet can have a high residual magnetic flux density. When (M2 / M1) × 100 is 10.0 or less, most of the wax is easily removed from the molded body during the molding process, and less wax remains in the anisotropic bonded magnet. The wax content in the molded body is reduced to a value of 0.0% by mass or more and 0.1% by mass or less during the molding process. Therefore, the wax content in the anisotropic bonded magnet is controlled to a value of 0.0 mass% or more and 0.1 mass% or less. As a result, the anisotropic bonded magnet can have high mechanical strength. From the viewpoint of easily achieving both high residual magnetic flux density and high mechanical strength, (M2 / M1)×100 may be 2.5 to 8.0, 2.0 to 5.0, or 2.0 to 6.0. If (M2 / M1)×100 is less than 2, the anisotropic bonded magnet will have difficulty having high residual magnetic flux density. If (M2 / M1)×100 is greater than 10, the anisotropic bonded magnet will have difficulty having high mechanical strength.

[0048] The mass M3 of wax in the molded body after the molding process is less than the mass M2 of wax in the compound, and the mass of wax removed from the molded body (compound) by the molding process is M2-M3. On the other hand, the total mass M1 of the magnet powder and thermosetting resin in the compound (molded body) does not change significantly during the molding process. Therefore, M2-M3 is approximately or exactly equal to the difference (Mi-Mf) between the mass Mi of the compound supplied into the mold and the mass Mf of the molded body after the molding process. (M2-M3 ≈ Mi-Mf.) In other words, the wax content Cw in the molded body (or in the anisotropic bonded magnet) can be calculated based on the difference (Mi-Mf) between the mass Mi of the compound supplied into the mold and the mass Mf of the molded body after the molding process. For example, the wax content Cw (unit: mass%) in the molded body after the molding process can be expressed as Cw = (M3 / Mf) × 100 (Equation A). The above M2-M3≈Mi-Mf can be rewritten as M3≈M2-(Mi-Mf) (Equation B). By substituting Equation B (i.e., M3) into Equation A, we derive Equation C, which is Cw≈[{M2-(Mi-Mf)} / Mf]×100.

[0049] The molding process may include a first pressurization step and a second pressurization step following the first pressurization step. In the first pressurization step, the pressure acting on the compound in the mold heated at the molding temperature Tm (molding pressure) increases continuously from 0 MPa to a first pressure P1 (unit: MPa) and is maintained at the first pressure P1 for a predetermined time. In the second pressurization step, the pressure acting on the compound in the mold heated at the molding temperature Tm (molding pressure) increases continuously from the first pressure P1 to a second pressure P2 (unit: MPa) and is maintained at the second pressure P2 for a predetermined time. In other words, the second pressure P2 is higher than the first pressure P1. By pressurizing the compound at a relatively low first pressure P1 in the first pressurization step, excessive compression of the compound is suppressed, friction or contact between the magnetic particles is suppressed, the magnetic particles in the compound are more likely to rotate, and the magnetic particles are more likely to be oriented along the magnetic field. In the second pressurization process, applying a relatively high second pressure P2 to the molded body (compound) makes it easier to remove the wax from the molded body.

[0050] For example, the first pressure P1 may be greater than 0 MPa and less than 500 MPa. For example, the second pressure P2 may be 500 MPa or more and 2000 MPa or less, preferably 700 MPa or more and 2000 MPa or less, and more preferably 980 MPa or more and 2000 MPa or less. The lower the first pressure P1, the easier it is to suppress excessive compression of the compound, the easier it is for each magnetic particle in the compound to rotate, and the easier it is for the magnetization direction of each magnetic particle to be oriented approximately parallel to the magnetic field. The higher the second pressure P2, the easier it is for the molded body (compound) to be compressed, and the easier it is for the wax to be removed from the molded body.

[0051] In the molding process, wax may be removed from the molded body by continuously increasing the pressure (molding pressure) acting on the compound in the mold heated at the molding temperature Tm from 0 MPa to a second pressure P2. In this case as well, the molding pressure may be maintained at the second pressure P2 for a predetermined time.

[0052] In the molding process, the application of a magnetic field to the compound inside the mold may begin after the temperature of the heated mold reaches the molding temperature Tm. As a result, due to the lubricating properties of the liquefied wax, the magnetic particles slide easily against each other, each magnetic particle rotates easily, and each magnetic particle is easily oriented along the magnetic field.

[0053] In the molding process, the application of a magnetic field to the compound in the mold may begin simultaneously with the compression of the compound in the mold. Alternatively, the application of a magnetic field to the compound in the mold may begin earlier than the compression of the compound. If the application of a magnetic field to the compound in the mold begins earlier than the compression of the compound, the magnetic particles in the compound are more likely to rotate while the compression of the compound is suppressed. As a result, the magnetic particles are more likely to be oriented along the magnetic field. In the molding process, the application of a magnetic field to the compound in the mold may be stopped when the molding pressure begins to decrease. In other words, the application of a magnetic field to the compound in the mold may be stopped simultaneously with the end of the second pressurization process. Alternatively, the application of a magnetic field to the compound in the mold may be stopped simultaneously with the start of the second pressurization process. In other words, the application of a magnetic field to the compound in the mold may be stopped when the molding pressure reaches the second pressure P2.

[0054] The magnetic field H may be a static magnetic field (a continuous, constant magnetic field). The magnetic field H may also be a pulsed magnetic field (a pulsed magnetic field). The higher the strength of the magnetic field H, the better the orientation of the magnetic powder in the molded body. The longer the time the magnetic field H is applied to the compound in the mold, the better the orientation of the magnetic powder in the molded body. The more times the magnetic field H is applied to the compound in the mold, the better the orientation of the magnetic powder in the molded body.

[0055] The strength of the static magnetic field used in the manufacture of anisotropic bonded magnets is lower than that of a pulsed magnetic field. When the magnetic field H is a static magnetic field, applying the magnetic field H to the compound in the mold for a sufficiently long time causes each magnet particle in the compound to be sufficiently oriented along the magnetic field. For example, the strength of the static magnetic field may be 0.5T (Tesla) or more and 2.5T or less, preferably 1.0T or more and 2.5T or less, and more preferably 2.0T or more and 2.5T or less. For example, the time for which the static magnetic field is applied to the compound in the mold may be 0.08 minutes or more and 4 minutes or less, preferably 0.5 minutes or more and 4 minutes or less, and more preferably 1 minute or more and 4 minutes or less.

[0056] The pulsed magnetic field used in the manufacture of anisotropic bonded magnets has a higher intensity than a static magnetic field. Because the pulsed magnetic field is generated instantaneously, the amount of heat generated by the current required to generate the pulsed magnetic field (Joule heating in the coil) can be suppressed. By instantaneously applying a high-intensity pulsed magnetic field to the compound in the mold, each magnet particle in the compound is instantaneously and sufficiently oriented along the magnetic field. From the perspective of the limits of pulsed magnetic field intensity that can be generated by commercially available pulsed magnetic field generators and cost, the upper limit of the pulsed magnetic field intensity is about 12T. For example, the intensity of the pulsed magnetic field may be between 4T and 12T, or between 8T and 12T. The pulsed magnetic field may be applied to the compound once or multiple times. For example, a pulsed magnetic field with an intensity of 4T or more may be applied to the compound once or more times.

[0057] <Cooling process> The cooling process follows the molding process described above. In the cooling process, the mold containing the molded body is cooled from the molding temperature Tm to a temperature below the wax dropping point (e.g., room temperature). During the cooling process, it is not necessary to apply a magnetic field H to the molded body in the mold. However, a magnetic field H may be applied to the molded body in the mold during the cooling process.

[0058] The thermosetting resin (uncured) in the molded body is softened by heating the mold during the molding process. The softened thermosetting resin in the molded body solidifies during the cooling process. If wax remains in the molded body, the liquefied wax in the molded body solidifies during the cooling process. For these reasons, the mechanical strength of the molded body increases during the cooling process, suppressing deformation and breakage of the molded body in each process after the cooling process. As a result, the mechanical strength of the anisotropic bonded magnet obtained in the final product tends to increase. If the demagnetization process is performed before the thermosetting resin (uncured) and wax in the molded body have sufficiently solidified, the position and orientation of each magnet particle in the molded body are likely to change due to the application of a magnetic field to the molded body during the demagnetization process, and the orientation of the magnet powder in the molded body may be impaired. In other words, if the demagnetization process is performed immediately after the molding process without a cooling process, the orientation of the magnet powder in the molded body may be impaired during the demagnetization process.

[0059] For example, the method for cooling the mold containing the molded body may be natural cooling of the mold. During the cooling process (the process in which the mold temperature T decreases to room temperature), the molding pressure may gradually decrease from the second pressure P2 to 0 MPa. At the start of the cooling process (the end of the molding process), the molding pressure may be instantaneously released. In other words, at the start of the cooling process (the end of the molding process), the molding pressure may instantaneously decrease from the second pressure P2 to 0 MPa.

[0060] <Demagnetization process> In the demagnetization process, the molded body is demagnetized by applying a magnetic field (reverse magnetic field) in the opposite direction to the magnetic field H used in the molding process. The demagnetization process may be performed after the cooling process. The demagnetization process may also be performed simultaneously with the cooling process. That is, the molded body may be demagnetized by applying a reverse magnetic field to the molded body housed in the mold in parallel with the cooling of the mold. After the molded body is demagnetized simultaneously with the cooling process, the molded body is removed from the mold. The demagnetization process may be performed by the manufacturing apparatus 10 (molding apparatus) used in the molding process. After the cooling process, the molded body removed from the mold may be demagnetized by another magnetic field application device.

[0061] <Thermosetting process> The thermosetting process is performed after the demagnetization process. In the thermosetting process, the molded body is heated to a temperature above the thermosetting temperature of the thermosetting resin. As a result, the thermosetting resin in the molded body hardens. The magnetic powder in the molded body is bound together by the hardened thermosetting resin, and each magnetic particle is fixed within the molded body. In the thermosetting process, multiple molded bodies that have undergone the demagnetization process may be heated simultaneously.

[0062] In the thermosetting process, the temperature of the molded body increases from room temperature to a temperature above the thermosetting temperature of the thermosetting resin. Before the temperature of the molded body reaches the thermosetting temperature during the thermosetting process, the thermosetting resin (and wax) in the molded body softens, and the molded body itself softens. The position and orientation of each magnet particle in the softened molded body are not sufficiently fixed by the softened thermosetting resin. If the thermosetting process is carried out without performing a demagnetization process, the magnetic force of the molded body itself will change the position and orientation of each magnet particle in the softened molded body, impairing the orientation of the magnet powder in the molded body. As a result, anisotropic bonded magnets will have difficulty achieving a high residual magnetic flux density. For example, each magnet particle located near the surface of the softened molded body will protrude from the surface of the molded body along with the thermosetting resin (and wax). In other words, one or more protrusions containing magnet particles and thermosetting resin are formed on the surface of the molded body. This is because, in areas of the surface of a molded body that has not undergone a demagnetization process, where the magnetic flux density is high, the magnetic force is more likely to act on the magnet particles located near the surface of the molded body.

[0063] <Magnetization process> The magnetization process is performed after the heat curing process. In the magnetization process, a magnetic field H in the same direction as the magnetic field H used in the molding process is applied to the molded body. As a result, the molded body is magnetized and becomes an anisotropic bonded magnet. As shown in Figure 2, the overall magnetization direction M of the anisotropic bonded magnet 2B is approximately or perfectly parallel to the direction of the magnetic field H applied to the compound (molded body) in the molding process. In other words, the magnetization direction m of each magnet particle 3 in the anisotropic bonded magnet 2B is approximately or perfectly parallel to the magnetic field H.

[0064] <Analysis method> To analyze and identify the composition of the molded body and the anisotropic bonded magnet, samples obtained by grinding the molded body and the anisotropic bonded magnet may be analyzed. To analyze and identify the composition of the compound itself retrospectively from the molded body and the anisotropic bonded magnet, samples obtained by grinding the molded body and the anisotropic bonded magnet may be analyzed. Furthermore, the sample obtained by grinding may be dissolved in an organic solvent, and the magnet powder constituting the sample may be separated from the resin composition dissolved in the organic solvent. The separated resin composition and magnet powder may each be analyzed individually. Even if the composition of the uncured compound is to be analyzed and identified, the compound may be dissolved in an organic solvent, and the magnetic powder may be separated from the resin composition dissolved in the organic solvent. The separated resin composition and magnetic powder may each be analyzed individually. For example, each component constituting the resin composition (thermosetting resin, wax, etc.) may be analyzed and identified by one or more analytical methods selected from the group consisting of infrared spectroscopy (IR), nuclear magnetic resonance (NMR), mass spectrometry (MS), gas chromatography (GC), and high-performance liquid chromatography (HPLC). For example, magnetic powder may be analyzed and identified by one or more analytical methods selected from the group consisting of X-ray fluorescence analysis (XRF), inductively coupled plasma (ICP) emission spectroscopy, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS or EDX), and mass spectrometry. The residual magnetic flux density Br1 of the molded body (or anisotropic bonded magnet) and the residual magnetic flux density Br2 of the magnet powder itself may satisfy the following formula 1. Br1 = Br2 × (V2 / V1) × D (Equation 1) In Equation 1, V1 is the total volume of the molded body (or anisotropic bonded magnet). V2 is the volume of the magnet powder itself contained in the molded body (or anisotropic bonded magnet). V2 / V1 corresponds to the packing density of the magnet powder in the molded body (or anisotropic bonded magnet). D is the degree of orientation of the magnet powder in the molded body (or anisotropic bonded magnet). Based on Equation 1 above, the degree of orientation D is expressed as Br1 / {Br2×(V2 / V1)}. In other words, the degree of orientation D can be determined based on the measurements of Br1, Br2, V1, and V2. A high degree of orientation means that the easy magnetization axis in each magnet particle constituting the magnet powder contained in the molded body is oriented. In other words, a high degree of orientation means that the magnetization direction of each magnet particle constituting the magnet powder contained in the anisotropic bonded magnet is oriented. For example, the degree of orientation D (in %) of the magnet powder in a molded body (or anisotropic bonded magnet) may be 80% or more and 100% or less.

[0065] (Compound) <Magnetic powder> As mentioned above, the magnetic powder is a powder containing Sm-Fe-N permanent magnets (SmFeN powder). For example, SmFeN powder has Sm2Fe as the main phase. 17 The powder may contain N3 (alloy). For example, at least a portion of the SmFeN powder may be an anisotropic magnetic powder containing Th2Zn type crystals (rhombohedral crystals) as the main phase. An anisotropic magnetic powder is a magnetic powder in which the individual magnetic particles constituting the magnetic powder are single crystals, or a magnetic powder in which the individual magnetic particles constituting the magnetic powder are composed of a large number of fine single crystal grains (magnetic domains), and the direction of the easy magnetization axis of each crystal grain is aligned in a specific direction. For example, at least a portion of the SmFeN powder may be an isotropic magnetic powder containing TbCu7 type crystals (hexagonal crystals) as the main phase. An isotropic magnetic powder is a magnetic powder in which the individual magnetic particles constituting the magnetic powder are composed of a large number of fine single crystal grains (magnetic domains), and the direction of the easy magnetization axis of each crystal grain is disordered.

[0066] The method for producing SmFeN powder is not limited. For example, a method for producing SmFeN powder may include the steps of forming an alloy powder containing Sm and Fe by a mechanical alloying method, and obtaining SmFeN powder by heating the alloy powder in nitrogen gas. SmFeN powder may also be produced by a rapid solidification method. In the rapid solidification method, molten alloy is supplied to the surface of a rotating water-cooled roll. As a result, the molten alloy is rapidly cooled and solidified on the surface of the water-cooled roll. SmFeN powder is obtained by crushing the solidified alloy. SmFeN powder may also be produced by the HDG (Hydrogenation Disproportion Desorption Recombination) method.

[0067] As the SmFeN powder, for example, unground powder (spherical magnetic powder) obtained by the build-up method of Nichia Corporation may be used. The surface of each magnetic particle constituting the SmFeN powder may be covered with an inorganic film by surface treatment. For example, the inorganic film may contain phosphate or silica-based compounds.

[0068] Average particle size d of SmFeN powder 50 The particle size may preferably be 0.5 μm to 100 μm, more preferably 1 μm to 10 μm, and even more preferably 2 μm to 3 μm. The average particle size of the SmFeN powder can be measured using a laser diffraction particle size distribution analyzer.

[0069] <wax> For example, the wax may be at least one composition selected from the group consisting of synthetic waxes, saturated fatty acids, saturated fatty acid salts, and saturated fatty acid esters. For example, the wax may be at least one wax selected from the group consisting of polyethylene wax, amide wax, and montan wax. Commercial polyethylene waxes include Ricolb H12 and Ricowax PE520. TM , and Ricowax PED191 TMAt least one selected from the group consisting of (the above are product names manufactured by Clariant Chemicals, Ltd.) may be used. As commercially available products of the amide wax, Licolube FA TM (product name manufactured by Clariant Chemicals, Ltd.), and DISPARLON 6650 TM (product name manufactured by Kusumoto Chemicals, Ltd.) may be used. As commercially available products of the montan wax, Licowax E TM , Licowax OP TM , Licolube E TM and Licolube WE40 TM (the above are product names manufactured by Clariant Chemicals, Ltd.) may be used. Any of Licowax E TM , Licowax OP TM , Licolube E TM and Licolube WE40 TM is a montanic acid ester.

[0070] Depending on requirements such as the orientation of the magnet powder, the mold release property of the molded body, the molding temperature and molding pressure in the molding process, and the melting point, dropping point and melt viscosity of the wax, etc. in the design of the compound, the wax may be appropriately selected. From the viewpoint of being easy to improve the orientation of the magnet powder in the molding process, among the above waxes, montan wax (montanic acid ester) is preferable, and Licowax E TM is particularly preferable. The dropping point of Licowax E TM (montanic acid ester) is 82 °C, and the melt viscosity of Licowax E TM (montanic acid ester) at 100 °C is 30 mPa·s.

[0071] The compound may contain one of the above waxes. The compound may also contain a plurality of the above waxes.

[0072] <Resin Composition> In this embodiment, "resin composition" means the remaining portion of the compound (non-volatile components) excluding the magnetic powder and wax. The resin composition includes at least a thermosetting resin. The resin composition may further include at least one component selected from the group consisting of curing agents, curing accelerators, coupling agents, flame retardants, and flow aids. The compound itself may contain an organic solvent.

[0073] The resin composition functions as a binder, binding together multiple magnetic particles that make up the magnetic powder. In other words, the resin composition imparts mechanical strength to the anisotropic bonded magnet manufactured from the compound. For example, in the molding process described above, the resin composition is filled between multiple magnetic particles, binding them together. As the resin composition heats up, the cured resin material binds the magnetic particles together more firmly.

[0074] For example, the thermosetting resin contained in the resin composition may be at least one resin selected from the group consisting of epoxy resins, phenolic resins (including phenol novolac resins), maleimide compounds, polyimides, polyamides, and polyamideimides. If the compound contains both epoxy resin and phenolic resin, the phenolic resin may function as a curing agent for the epoxy resin. The thermosetting resin in the compound may be at least one of an uncured resin and a semi-cured resin.

[0075] The mass of the magnetic powder in the compound is expressed as Mm (unit: g), and the mass of the entire resin composition in the compound is expressed as Mr (unit: g). The occupancy rate is defined as Mm / (Mm+Mr)×100. The packing factor may be 90.0 or more and 99.9 or less, preferably 95.0 or more and 99.5 or less, and more preferably 96.0 or more and 98.0 or less. When the packing factor is 90.0 or more, the anisotropic bonded magnet tends to have a sufficiently high residual magnetic flux density. When the packing factor is 99.9 or less, the anisotropic bonded magnet tends to have a sufficiently high mechanical strength.

[0076] <Epoxy resin> Any epoxy resin can be used as long as it has two or more epoxy groups in one molecule. From the viewpoint of improving the heat resistance (mechanical strength at high temperatures) of anisotropic bonded magnets, heat-resistant epoxy resins such as naphthalene-type epoxy resins are preferred.

[0077] For example, epoxy resins include biphenyl-type epoxy resins, stilbene-type epoxy resins, diphenylmethane-type epoxy resins, sulfur atom-containing epoxy resins, novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, salicylaldehyde-type epoxy resins, copolymer epoxy resins of naphthols and phenols, epoxidized aralkyl-type phenol resins, bisphenol-type epoxy resins, glycidyl ether-type epoxy resins of alcohols, glycidyl ether-type epoxy resins of paraxylylene-modified phenol resins and / or metaxylylene-modified phenol resins, and glycidyl ether-type terpene-modified phenol resins. The epoxy resin may be at least one selected from the group consisting of epoxy resins, cyclopentadiene-type epoxy resins, glycidyl ether-type epoxy resins of polycyclic aromatic ring-modified phenol resins, glycidyl ether-type epoxy resins of naphthalene ring-containing phenol resins, glycidyl ester-type epoxy resins, glycidyl-type or methylglycidyl-type epoxy resins, alicyclic epoxy resins, halogenated phenol novolac-type epoxy resins, orthocresol novolac-type epoxy resins, hydroquinone-type epoxy resins, trimethylolpropane-type epoxy resins, and linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid. As highly crystalline epoxy resins, hydroquinone-type epoxy resins, bisphenol-type epoxy resins, thioether-type epoxy resins, and biphenyl-type epoxy resins may be used.

[0078] At least some of the epoxy resins may be naphthalene-type epoxy resins having a naphthalene structure. Naphthalene-type epoxy resins are solid at room temperature. When the compound contains a naphthalene-type epoxy resin, the anisotropic bonded magnets tend to have high mechanical strength at both room temperature and high temperatures. For example, the naphthalene-type epoxy resin may be at least one epoxy resin selected from the group consisting of naphthalene diepoxy compounds, naphthylene ether-type epoxy resins, naphthalene novolac-type epoxy resins, methylene-bonded dimers of naphthalene diepoxy compounds, and methylene-bonded compounds of naphthalene monoepoxy compounds and naphthalene diepoxy compounds.

[0079] The naphthalene-type epoxy resin is preferably at least one of a trifunctional epoxy resin and a tetrafunctional epoxy resin. More preferably, the naphthalene-type epoxy resin is a tetrafunctional epoxy resin. When the naphthalene-type epoxy resin contained in the compound is at least one of a trifunctional epoxy resin and a tetrafunctional epoxy resin, the naphthalene-type epoxy resins are crosslinked three-dimensionally with each other during the thermosetting process, forming a strong crosslinked network. As a result, the movement of the naphthalene-type epoxy resin in the anisotropic bonded magnet is easily suppressed at high temperatures. In other words, the glass transition temperatures of the trifunctional epoxy resin and the tetrafunctional epoxy resin are higher than those of the difunctional epoxy resin. Therefore, when the naphthalene-type epoxy resin contained in the compound is at least one of a trifunctional epoxy resin and a tetrafunctional epoxy resin, the anisotropic bonded magnet tends to have high mechanical strength at high temperatures.

[0080] For example, as a trifunctional or tetrafunctional naphthalene-type epoxy resin, HP-4700 manufactured by DIC Corporation. TM HP-4710 TM HP-4770 TM EXA-5740 TM , or EXA-7311-G4 TMCommercially available products such as the above may be used. The naphthalene-type epoxy resin contained in the compound may be a bifunctional epoxy resin. HP-4032 is an example of a bifunctional naphthalene-type epoxy resin. TM Or HP-4032D TM Commercially available products such as those listed above may be used. The naphthalene-type epoxy resin contained in the compound powder may also be a β-naphthol-type epoxy resin.

[0081] The compound may contain one of the epoxy resins listed above. The compound may contain multiple types of epoxy resins listed above.

[0082] <Hardening agent / phenol resin> Curing agents are classified into two types: those that cure epoxy resins at low temperatures to room temperature, and heat-curing curing agents that cure epoxy resins upon heating. Examples of curing agents that cure epoxy resins at low temperatures to room temperature include aliphatic polyamines, polyaminoamides, and polymercaptans. Examples of heat-curing curing agents include aromatic polyamines, acid anhydrides, phenol novolac resins, and dicyandiamide (DICY).

[0083] When a curing agent is used that cures epoxy resin in the range of low temperatures to room temperature, the glass transition point of the cured epoxy resin is low, and the cured epoxy resin tends to be soft. As a result, anisotropic bonded magnets manufactured from the compound also tend to be soft. Therefore, from the viewpoint of improving the heat resistance of anisotropic bonded magnets, the curing agent may preferably be a heat-curing type curing agent, more preferably a phenolic resin, and even more preferably a phenol novolac resin. In particular, by using a phenol novolac resin as the curing agent, it is easier to obtain a cured epoxy resin with a high glass transition point. As a result, the heat resistance of the anisotropic bonded magnet is easily improved.

[0084] For example, the phenol resin may be at least one selected from the group consisting of aralkyl-type phenol resins, dicyclopentadiene-type phenol resins, salicylaldehyde-type phenol resins, novolac-type phenol resins, copolymer phenol resins of benzaldehyde-type phenol and aralkyl-type phenol, paraxylylene and / or metaxylylene-modified phenol resins, melamine-modified phenol resins, terpene-modified phenol resins, dicyclopentadiene-type naphthol resins, cyclopentadiene-modified phenol resins, polycyclic aromatic ring-modified phenol resins, biphenyl-type phenol resins, and triphenylmethane-type phenol resins. The phenol resin may also be a copolymer composed of two or more of the above-mentioned phenol resins.

[0085] The phenol novolac resin may be a resin obtained by condensing or co-condensing phenols and / or naphthols with aldehydes under an acidic catalyst. The phenols constituting the phenol novolac resin may be at least one selected from the group consisting of phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol. The naphthols constituting the phenol novolac resin may be at least one selected from the group consisting of α-naphthol, β-naphthol, and dihydroxynaphthalene. The aldehydes constituting the phenol novolac resin may be at least one selected from the group consisting of formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde.

[0086] The curing agent may be, for example, a compound having two phenolic hydroxyl groups in one molecule. The compound having two phenolic hydroxyl groups in one molecule may be, for example, at least one selected from the group consisting of resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenols.

[0087] Examples of commercially available phenolic resins include Tamanol 758 and 759 manufactured by Arakawa Chemical Industries, Ltd., and HP-850N manufactured by Showa Denko Materials Corporation. TM These are some examples.

[0088] The compound may contain one of the above-mentioned phenolic resins. The compound may contain multiple types of the above-mentioned phenolic resins.

[0089] The ratio of hydroxyl group equivalents of the phenol resin to the epoxy equivalents of the epoxy resin may be 0.5 to 1.5, 0.9 to 1.4, 1.0 to 1.4, or 1.0 to 1.2. In other words, the ratio of active groups (phenolic OH groups) in the phenol resin that react with epoxy groups in the epoxy resin is preferably 0.5 to 1.5 equivalents, more preferably 0.9 to 1.4 equivalents, even more preferably 1.0 to 1.4 equivalents, and particularly preferably 1.0 to 1.2 equivalents per equivalent of epoxy groups in the epoxy resin. If the ratio of active groups in the phenol resin is less than 0.5 equivalents, the amount of OH per unit weight of the cured epoxy resin decreases, and the curing rate of the resin composition (epoxy resin) decreases. Also, if the ratio of active groups in the phenol resin is less than 0.5 equivalents, the glass transition temperature of the resulting cured product tends to decrease, making it difficult to obtain a sufficient elastic modulus of the cured product. On the other hand, when the ratio of active groups in the phenolic resin is 1.5 equivalents or less, anisotropic bonded magnets tend to have high mechanical strength.

[0090] <Maleimide compounds: Bismaleimides and aminophenol adducts> Maleimide compounds are at least one compound from among bismaleimide and its aminophenol adducts. The imide ring constituting bismaleimide is rigid. The phenyl ring constituting the aminophenol adduct of bismaleimide is also rigid. Due to these molecular structures, maleimide compounds have superior heat resistance and are less susceptible to thermal expansion compared to conventional thermosetting resins (e.g., epoxy resins). In particular, the crosslinking density of the aminophenol adduct is relatively high. Due to the above-mentioned characteristics of maleimide compounds, maleimide compounds (especially aminophenol adducts) have superior heat resistance and are less susceptible to thermal expansion compared to conventional thermosetting resins (e.g., epoxy resins). In other words, maleimide compounds (especially aminophenol adducts) are less likely to soften and deform at high temperatures. Therefore, anisotropic bonded magnets manufactured from compounds containing maleimide compounds (especially aminophenol adducts) can have high mechanical strength at high temperatures (e.g., 150°C).

[0091] Bismaleimides (bismaleimides (a) below) are compounds (e.g., monomers or polymers) containing structural units having two or more maleimide groups. The aminophenol adducts of bismaleimides are addition reaction products (e.g., addition polymers) of bismaleimides (a) and aminophenols (b). In other words, aminophenol adducts of bismaleimides can be obtained by addition reactions (e.g., addition polymerization reactions) of bismaleimides (a) and aminophenols (b). For example, one molecule of an aminophenol adduct may be synthesized by the reaction of one molecule of bismaleimides (a) with one or more molecules of aminophenols (b). Epoxy compounds (c) (epoxy resins) may be added to maleimide compounds (especially aminophenol adducts). When a maleimide compound (especially an aminophenol adduct) to which epoxy compound (c) has been added is thermally cured, the maleimide compound (especially an aminophenol adduct) is modified by epoxy compound (c), forming a complex network structure composed of the maleimide compound (especially an aminophenol adduct) and epoxy compound (c). As a result, the glass transition temperature of the cured product formed from the maleimide compound (especially an aminophenol adduct) and epoxy compound (c) tends to increase, and the mechanical strength of the anisotropic bonded magnet at high temperatures tends to increase.

[0092] Bismaleimides (a) are represented by the following chemical formula A. [ka] R in the above chemical formula A 1 X is an n-valent organic group. 1 and X 2 Each is a monovalent atom selected from hydrogen or halogen, or a monovalent organic group. 1 and X 2 They may be the same, X 1 and X 2 These elements may be different from each other. In the above chemical formula A, n is an integer greater than or equal to 2.

[0093] For example, bismaleimides (a) may be at least one compound selected from the group consisting of ethylenebismaleimide, hexamethylenebismaleimide, m-phenylenebismaleimide, p-phenylenebismaleimide, 2,2-bis[4-(4-maleimoidphenoxy)phenyl]propane (also known as bisphenol A bis(4-maleimidephenyl ether)), 4,4'-bismaleimidediphenylmethane (also known as 4,4'-diphenylmethanebismaleimide), 4,4'-diphenyletherbismaleimide, 4,4'-diphenylsulfonebismaleimide, 4,4'-dicyclohexylmethanebismaleimide, m-xylylenebismaleimide, p-xylylenebismaleimide, and 4,4'-phenylenebismaleimide. The compound powder may further contain monomaleimides as needed. The monomaleimides may be, for example, N-3-chlorophenylmaleimide or N-4-nitrophenylmaleimide.

[0094] The aminophenols (b) that constitute the aminophenol adduct of bismaleimide are represented by the following chemical formula B. [ka] In chemical formula B, R 2 m is a monovalent atom selected from hydrogen or a halogen, or a monovalent organic group. In chemical formula B, m is an integer between 1 and 5.

[0095] From the bismaleimides (a) represented by the above chemical formula A and the aminophenols (b) represented by the above chemical formula B, an aminophenol adduct represented by the following chemical formula C may be synthesized. In the chemical formula C below, α is an integer between 1 and n, inclusive. R in the following chemical formula C 1 X is an n-valent organic group. 1 and X 2 Each is a monovalent atom selected from hydrogen or halogen, or a monovalent organic group. 1 and X 2 They may be the same, X 1and X 2 These elements may be different from each other. In the following chemical formula C, n is an integer greater than or equal to 2. In the chemical formula C below, R 2 m is a monovalent atom selected from hydrogen or a halogen, or a monovalent organic group. In the following chemical formula C, m is an integer between 1 and 5. [ka]

[0096] For example, aminophenols (b) may be at least one compound selected from the group consisting of o-aminophenol, m-aminophenol, p-aminophenol, o-aminocresol, m-aminocresol, p-aminocresol, aminoxylenol, aminochlorophenol, aminobromuphenol, aminocatechol, aminoresorcinol, aminobis(hydroxyphenol)propane, and aminooxybenzoic acid. The compound powder may further contain compounds other than aminophenols (b) as comonomers that polymerize with bismaleimides (a). For example, the compound powder may further contain at least one compound selected from the group consisting of aromatic amines other than aminophenols (b), vinyl compounds, allyl compounds, allylphenols, and isocyanates as a comonomer that polymerizes with bismaleimides (a).

[0097] The epoxy compound (c) added to the maleimide compound may have two or more epoxy groups in its molecule. For example, epoxy compound (c) may be at least one compound selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, glycidyl ester resin of polycarboxylic acid, polyglycidyl ether of polyol, urethane-modified epoxy resin, fatty acid type polyepoxide obtained by epoxidizing an unsaturated compound, alicyclic type polyepoxide obtained by epoxidizing an unsaturated compound, epoxy resin having a heterocyclic ring, and epoxy resin obtained by glycidylating an amine.

[0098] The mass proportion of aminophenols (b) may be 0 to 40 parts by mass, 5 to 40 parts by mass, preferably 10 to 30 parts by mass, per 100 parts by mass of bismaleimides (a). When the mass proportion of aminophenols (b) is 5 parts by mass or more, the compatibility between the addition product and the epoxy compound (c) is sufficient. When the mass proportion of aminophenols (b) is 40 parts by mass or less, the number of amino groups in the aminophenol adduct is appropriately suppressed, and the aminophenol adduct tends to have excellent heat resistance. The reaction temperature of bismaleimides (a) and aminophenols (b) may be, for example, 50 to 200°C, preferably 80 to 180°C. The reaction time of bismaleimides (a) and aminophenols (b) may be appropriately adjusted within the range of several minutes to several tens of hours.

[0099] The proportion of maleimide compounds among all thermosetting resins contained in the compound powder may be, for example, 30 to 100% by mass, or 30 to 80% by mass.

[0100] As a resin composition containing an aminophenol adduct of bismaleimide, KIR-3 TM KIR-30 TM KIR-50 TM and KIR-100 TM At least one commercially available product selected from the above (product names of Kyocera Corporation) may be used. KIR-3 TM This is an example of an aminophenol adduct that does not contain epoxy compound (c) (epoxy resin). KIR-30 TM This is an example of an aminophenol adduct to which epoxy compound (c) (epoxy resin) has been added.

[0101] For example, KIR-3 TM and KIR-30 TM It contains 4,4'-diphenylmethanebismaleimide, represented by the following chemical formula 1, as bismaleimide. [ka]

[0102] For example, KIR-3 TM and KIR-30 TM It contains m-aminophenol represented by the following chemical formula 2. [ka]

[0103] For example, KIR-30 TM This product contains a bisphenol A type epoxy resin, represented by the following chemical formula 3, as an epoxy compound (epoxy resin). In the following chemical formula 3, n is a non-negative integer. [ka]

[0104] For example, KIR-3 TM and KIR-30 TM It contains an aminophenol-1 adduct represented by the following chemical formula 4. The aminophenol-1 adduct is synthesized by the addition reaction of one molecule of 4,4'-diphenylmethanebismaleimide and one molecule of m-aminophenol. [ka]

[0105] For example, KIR-3 TM and KIR-30 TM This includes an aminophenol 2 adduct represented by the following chemical formula 5. The aminophenol 2 adduct may be synthesized by an addition reaction between one molecule of 4,4'-diphenylmethanebismaleimide and two molecules of m-aminophenol. The aminophenol 2 adduct may also be synthesized by an addition reaction between one molecule of the above aminophenol 1 adduct and one molecule of m-aminophenol. [ka]

[0106] <Polyimide> For example, the polyimide may be a dehydrated polycondensate of a tetracarboxylic anhydride and 4,4'-bis(3-aminophenoxy)biphenyl. The polyimide is Aurum PL450C. TM Aurum PL500A TM Aurum PL6200 TM Aurum PD450L TM (The above products are manufactured by Mitsui Chemicals, Inc.) SolverPI-5600 TM (Products manufactured by Solver, Inc.), and surprim TM It may be at least one resin selected from products manufactured by Mitsubishi Gas Chemical Company, Inc.

[0107] <Polyamide> For example, the polyamide may be at least one of the following: particles of nylon 6 obtained from ε-caprolactam, and particles of nylon 12 obtained from lauryl lactam. For example, the polyamide may be particles made of nylon 6 (TR-1 manufactured by Toray Industries, Inc.). TM and TR-2 TM ), and particles made of nylon 12 (SP-500 manufactured by Toray Industries, Inc.) TM and SP-10 TM It may be at least one resin selected from the group consisting of ).

[0108] <Polyamide-imide> For example, the polyamide-imide may be a polyamide-imide having a siloxane structure. The polyamide-imide may have two or more carboxyl groups at at least one of the ends of the molecular chain of the polyamide-imide. The polyamide-imide may be the polyamide-imide described in Japanese Patent Publication No. 2019-48948.

[0109] <Other resins> The resin composition may contain the above-mentioned thermosetting resins. In addition to the thermosetting resins, the resin composition may further contain other resins. For example, the resin composition may contain thermoplastic resins in addition to thermosetting resins, provided that the mechanical strength of the anisotropic bonded magnet is not impaired. For example, the resin composition may further contain at least one other resin selected from the group consisting of polyphenylene sulfide resin, acrylic resin, methacrylic resin, polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, and silicone resin.

[0110] <Curing accelerator> For example, the curing accelerator may contain imidazoles. For example, the imidazole-based curing accelerator may be at least one compound selected from 1-cyanoethyl-2-undecylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, and 1-cyanoethyl-2-phenylimidazole. A commercially available imidazole-based curing accelerator is, for example, 2MZ-H TM C11Z TM C17Z TM , 1,2DMZ TM ,2E4MZ TM ,2PZPW TM ,2P4MZ TM , 1B2MZ TM , 1B2PZ TM , 2MZ-CN TM , C11Z-CN TM , 2E4MZ-CN TM , 2PZ-CN TM C11Z-CNS TM , 2P4MHZ TM TPZ TM , and SFZ TM (The above are product names manufactured by Shikoku Chemicals Co., Ltd.) and others. Among these, C17Z TM (Imidazole-based curing accelerators) are preferred. By using the above curing accelerator, an anisotropic bonded magnet with excellent heat resistance can be obtained.

[0111] The curing accelerator may contain a tetra-substituted phosphonium·tetra-substituted borate. The tetra-substituted phosphonium·tetra-substituted borate may be a compound represented by the following formula (I-0).

Chemical formula

[0112] R 51 ~R 58 in the general formula (I-0) above may be at least one organic group selected from the group consisting of a substituted or unsubstituted aliphatic hydrocarbon group, a substituted or unsubstituted aliphatic hydrocarbon oxy group, a substituted or unsubstituted carbonyl group, a substituted or unsubstituted oxycarbonyl group, a substituted or unsubstituted carbonyloxy group, a substituted or unsubstituted aromatic hydrocarbon group, and a substituted or unsubstituted aromatic hydrocarbon oxy group.

[0113] For example, the substituted or unsubstituted aliphatic hydrocarbon group may be an aliphatic hydrocarbon group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, an aryl group, and a vinyl group, and an organic group substituted with an alkyl group, an alkoxy group, an aryl group, a hydroxyl group, an amino group, a halogen atom, etc.

[0114] The substituted or unsubstituted aliphatic hydrocarbon group includes a substituted or unsubstituted alicyclic hydrocarbon group. For example, the substituted or unsubstituted alicyclic hydrocarbon group may be a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group, etc., and an organic group substituted with an alkyl group, an alkoxy group, an aryl group, an aryloxy group, a hydroxyl group, an amino group, a halogen atom, etc.

[0115] For example, substituted or unsubstituted aromatic hydrocarbon groups, Aryl groups such as phenyl and tolyl groups; Alkyl-substituted aryl groups such as dimethylphenyl, ethylphenyl, butylphenyl, and tert-butylphenyl; Alkoxy group-substituted aryl groups such as methoxyphenyl, ethoxyphenyl, butoxyphenyl, and tert-butoxyphenyl; and These may be organic groups substituted with alkyl groups, alkoxy groups, aryl groups, aryloxy groups, amino groups, halogen atoms, etc.

[0116] In the above general formula (I-0), R 51 ~R 54 R may be a substituted or unsubstituted aliphatic hydrocarbon group, and 55 ~R 58 This may be a substituted or unsubstituted aromatic hydrocarbon group.

[0117] For example, the tetrasubstituted phosphonium tetrasubstituted borate may be at least one compound selected from the group consisting of tetrabutylphosphonium tetraphenyl borate, n-butyltriphenylphosphonium tetraphenyl borate, tetraphenylphosphonium tetraphenyl borate, trimethylphenylphosphonium tetraphenyl borate, diethylmethylphenylphosphonium tetraphenyl borate, diallylmethylphenylphosphonium tetraphenyl borate, (2-hydroxyethyl)triphenylphosphonium tetraphenyl borate, ethyltriphosphonium tetraphenyl borate, p-xylenebis(triphenylphosphonium tetraphenyl borate), tetraphenylphosphonium tetraethyl borate, tetraphenylphosphonium triethylphenyl borate, and tetraphenylphosphonium tetrabutyl borate. Among these, tetrabutylphosphonium tetraphenyl borate is preferred from the viewpoint of storage stability of the compound.

[0118] An example of a compound represented by the above general formula (I-0) is PX-4PB (manufactured by Hokko Chemical Co., Ltd., trade name).

[0119] By using the above-mentioned curing accelerator, an anisotropic bonded magnet with excellent heat resistance can be obtained. The compound may contain one of the above-mentioned curing accelerators. The compound may contain multiple types of the above-mentioned curing accelerators.

[0120] The amount of curing accelerator added is not particularly limited, as long as it is an amount that provides a curing acceleration effect. However, from the viewpoint of the curability of the thermosetting resin and the orientation of the magnetic powder in a magnetic field, the amount of curing accelerator added may be preferably 0.1 parts by mass or more and 30 parts by mass or less, and more preferably 1 part by mass or more and 15 parts by mass or less, per 100 parts by mass of epoxy resin. If the amount of curing accelerator added is less than 0.1 parts by mass, it is difficult to obtain a sufficient curing acceleration effect. If the amount of curing accelerator added exceeds 30 parts by mass, the storage stability of the compound tends to decrease. The content of the curing accelerator is preferably 0.001 parts by mass or more and 5 parts by mass or less, relative to the total mass of the epoxy resin and the curing agent (e.g., phenolic resin).

[0121] <Coupling agent> The coupling agent may be any coupling agent that reacts with glycidyl groups present in a resin composition such as an epoxy resin (epoxy compound). The coupling agent improves the adhesion between the magnet particles and the resin composition, thereby improving the mechanical strength of the anisotropic bonded magnet. The coupling agent that reacts with glycidyl groups may be, for example, a silane compound (silane coupling agent). For example, the silane coupling agent may be at least one selected from the group consisting of epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, acid anhydride silane (e.g., silane having succinic anhydride groups), and vinylsilane. The compound may contain one of the coupling agents described above. The compound may contain multiple coupling agents described above.

[0122] <Flame retardant> For the recyclability, moldability, and low cost of the compound, the resin composition may contain a flame retardant. For example, the flame retardant may be at least one compound selected from the group consisting of brominated flame retardants, phosphorus-based flame retardants, hydrated metal compound-based flame retardants, silicone-based flame retardants, nitrogen-containing compounds, hindered amine compounds, organometallic compounds, and aromatic engineering plastics. The compound may contain one of the above flame retardants, or may comprise multiple of the above flame retardants.

[0123] <Compound preparation> A compound is obtained by mixing magnetic powder, a resin composition, and wax. The mass of each component of the magnetic powder, the resin composition, and the wax is adjusted to match the composition of the compound described above. The magnetic powder, all components of the resin composition, and the wax may be mixed together at once. Alternatively, a mixture of the magnetic powder and the resin composition may be prepared in advance, and then the mixture and the wax may be mixed together.

[0124] A compound may be obtained by coating the surface of each magnetic particle constituting the magnetic powder with a resin composition using the following method, and then mixing the magnetic powder and wax.

[0125] A resin solution is prepared by uniformly stirring and mixing the resin composition in an organic solvent. In addition to the thermosetting resin, the resin solution may contain a curing agent, a curing accelerator, a coupling agent, a flame retardant, a flow aid, and a reactive diluent. The organic solvent is not particularly limited and can be any liquid that dissolves the resin composition. For example, the organic solvent may be at least one solvent selected from the group consisting of acetone, N-methylpyrrolidinone (N-methyl-2-pyrrolidone), γ-butyrolactone, dimethylformamide, dimethyl sulfoxide, methyl ethyl ketone, methyl isobutyl ketone, toluene, and xylene.

[0126] After stirring and mixing the above resin solution and magnet powder, the organic solvent is removed from the resin solution to obtain a mixed powder consisting of magnet powder and resin composition. As the organic solvent is removed from the resin solution, the resin composition adheres to the surface of each magnet particle constituting the magnet powder. The resin composition may adhere to the entire surface of each magnet particle. The resin composition may adhere to only a part of the surface of each magnet particle. The method for removing the organic solvent from the resin solution is not particularly limited. For example, the organic solvent may be removed from the resin solution by drying the mixture of the resin solution and magnet powder. For example, the method for drying the resin solution may be vacuum drying.

[0127] A compound may be obtained by further mixing the above mixed powder, which consists of magnetic powder and a resin composition, with wax.

[0128] <Tablet creation> Tablets made of the compound may be produced by compression molding of the compound filled into a mold. The dimensions and shape of the tablets are not particularly limited. For example, the tablets may be cylindrical. For example, the diameter of the cylinder may be 5 mm or more, and the height of the cylinder may be 5 mm or more. From the viewpoint of easily maintaining the shape of the tablet, the molding pressure for producing the tablets is preferably 100 MPa or more. If the molding pressure for producing the tablets is too high, the magnetic powder will not rotate easily and will not be easily oriented in the molding process described above. For this reason, the molding pressure for producing the tablets is preferably 600 MPa or less.

[0129] The present invention is not necessarily limited to the embodiments described above. Various modifications to the present invention are possible without departing from the spirit of the invention, and such modifications are also included in the present invention. [Examples]

[0130] The present invention will be described in detail by the following examples and comparative examples. The present invention is not limited to the following examples.

[0131] (Example 1) The compound (powder) of Example 1 was prepared by mixing magnet powder, thermosetting resin, curing accelerator, and wax in a plastic bottle for 1 hour. The capacity of the plastic bottle was 500 ml. As the magnet powder, SmFeN powder containing a main phase composed of Sm2Fe 17 N3 was used. The magnet powder was manufactured by Sumitomo Metal Mining Co., Ltd. As the thermosetting resin, KIR-30 TM was used. As described above, KIR-30 TM is a product manufactured by Kyocera Corporation. KIR-30 TM contains a mixture (uncured resin) of an aminophenol adduct of bismaleimide and an epoxy resin. As the curing accelerator, C17Z manufactured by Shikoku Kasei Kogyo Co., Ltd. TM was used. C17Z TM is an imidazole-based curing accelerator. As the wax, Licowax E manufactured by Clariant Chemicals Ltd. TM was used. Licowax E TM is a montanic acid ester. The dropping point of Licowax E TM is 82°C. The mass of the magnet powder in the compound is shown in Table 1 below. The mass of KIR-30 in the compound TM is shown in Table 1 below. The mass of C17Z in the compound TM is shown in Table 1 below. The mass of Licowax E in the compound TM is shown in Table 1 below. The unit of mass described in Table 1 below is gram (g). (M2 / M1)×100 is shown in Table 1 below. The definition of (M2 / M1)×100 is as described above.

[0132] Molded bodies and anisotropic bonded magnets were manufactured from the compound of Example 1 using the following method. The molding apparatus (hydraulic press) used was the TM-MPH10525-10A2TM model manufactured by Tamagawa Seisakusho Co., Ltd. TM It was used.

[0133] In the supply process, approximately 2g of compound was supplied into the mold of the molding device. The mold (cavity) was cubic in shape, and its volume was 7mm x 7mm x 7mm.

[0134] During the molding process, the mold was heated for 3-5 minutes until its temperature reached the molding temperature Tm. The molding temperature Tm was 100°C. In other words, the molding temperature Tm was higher than the dropping point of the wax (82°C) and lower than the thermosetting temperature of the thermosetting resin in the compound. The molding process consisted of the following first pressing step and a second pressing step following the first pressing step. In the first pressing step, the compound in the mold, heated to the molding temperature Tm, was compressed to 10 MPa (first pressure P1) for 1 minute while a static magnetic field was applied. The strength of the static magnetic field was maintained at 1.0 T. In the second pressing step, the compound (molded body) in the mold, heated to the molding temperature Tm, was compressed to 1000 MPa (second pressure P2) for 5 minutes. Through the molding process described above, a molded body was formed from the compound. In the second pressing process, the wax was removed from the molded body. During the second pressing process, the wax removed from the molded body was discharged out of the mold (cavity) through the clearance formed in the mold.

[0135] In the cooling process following the molding process, the mold containing the molded body was cooled from 100°C (molding temperature Tm) to 50°C (a temperature below the dropping point of wax). The mold was cooled in the air for approximately 10 minutes. After the cooling process, the molded body was removed from the mold.

[0136] In the demagnetization process following the cooling process, the molded body was demagnetized by applying a reverse magnetic field to it. The direction of the reverse magnetic field was opposite to the direction of the static magnetic field used in the molding process.

[0137] In the thermosetting process following the demagnetization process, the molded body was hardened by heating it at 180°C (a temperature above the thermosetting temperature of the thermosetting resin) for 20 minutes.

[0138] In the magnetization process following the thermosetting process, an anisotropic bonded magnet was obtained by applying a magnetic field to the molded body. The direction of the magnetic field used in the magnetization process was the same as the direction of the static magnetic field used in the molding process.

[0139] <Measurement of remanent magnetic flux density> The residual magnetic flux density Br (in Tesla) of anisotropic bonded magnets was measured. A high-sensitivity, superconducting magnet type (electromagnet) vibrating sample magnetometer (VSM) was used to measure Br. The vibrating sample magnetometer was manufactured by Tamagawa Seisakusho Co., Ltd. The residual magnetic flux density Br of the anisotropic bonded magnets in Example 1 is shown in Table 1 below.

[0140] <Measurement of crushing strength> Using a universal compression testing machine, compression pressure was applied to the end face of an anisotropic bonded magnet. That is, compression pressure was applied to the anisotropic bonded magnet in the height direction. The compression pressure was increased, and the compression pressure at which the anisotropic bonded magnet broke was measured. The compression pressure at which the anisotropic bonded magnet broke represents the crushing strength (unit: MPa). The universal compression testing machine used was the AG-10TRB manufactured by Shimadzu Corporation. TM The following was used. The crosshead speed during the crush strength measurement was 0.5 mm / min. During the crush strength measurement, the temperature of the anisotropic bonded magnet was maintained at room temperature. The crush strength of the anisotropic bonded magnet of Example 1 at room temperature is shown in Table 1 below. The crush strength of the anisotropic bonded magnet at 150°C was measured in the same manner as described above, except that the temperature of the anisotropic bonded magnet was maintained at 150°C during the crush strength measurement. During the crush strength measurement, the anisotropic bonded magnet was heated with a heater. The crush strength of the anisotropic bonded magnet of Example 1 at 150°C is shown in Table 1 below.

[0141] (Example 2) In the preparation of the compound in Example 2, KIR-3 was used as the thermosetting resin. TM As mentioned above, KIR-3 was used. TM This is a product manufactured by Kyocera Corporation. KIR-3 TM This is an uncured resin containing an aminophenol adduct of bismaleimide and not containing epoxy resin. KIR-3 in the compound of Example 2 TM The mass is shown in Table 1 below. Except for the matters mentioned above, the compound, molded body, and anisotropic bonded magnet of Example 2 were prepared in the same manner as in Example 1. The Br and crush strength of the anisotropic bonded magnet of Example 2 were measured in the same manner as in Example 1. The measurement results for Example 2 are shown in Table 1 below.

[0142] (Example 3) Polyamide-imides were synthesized using the following method.

[0143] A separable flask was used for the synthesis of polyamide-imide. The separable flask was equipped with a water meter with a stopcock connected to a reflux condenser, a thermometer, and a stirrer. The capacity of the separable flask was 1 liter. The capacity of the water meter was 25 mL. All of the following raw materials were stirred in the separable flask at 80°C for 30 minutes. 52.4 g (0.06 mol) of reactive silicone oil (X-22-9412 manufactured by Shin-Etsu Chemical Co., Ltd.) TM (Amine equivalent 437). 80.0 g (0.04 mol) of aliphatic diamine (D2000 manufactured by Mitsui Chemicals Fine, Inc.) TM (Amine equivalent 1000). 2.1g (0.01mol) bis(4-aminocyclohexyl)methane (Wandamin HM, manufactured by Shin Nippon Rika Co., Ltd.) TM ). 40.3 g (0.21 mol) of trimellitic anhydride (TMA). 357 g of N-methyl-2-pyrrolidone (NMP) as an aprotic polar solvent.

[0144] After stirring all the above raw materials, 120 mL of toluene (an aromatic hydrocarbon that can be azeotropically mixed with water) was supplied to the separable flask. After the supply of toluene, the contents of the separable flask were refluxed at approximately 160°C for 2 hours. After confirming that at least 3.8 mL of water had accumulated in the water metering receiver and that no further water distillation was observed, the toluene was removed from the contents of the separable flask by heating at approximately 190°C while removing the distillate from the water metering receiver. After the removal of toluene, the contents of the separable flask were cooled to 50°C. 32.5 g (0.13 mol) of 4,4'-diphenylmethane diisocyanate (MDI) was supplied to the separable flask as the aromatic diisocyanate. After the supply of 4,4'-diphenylmethane diisocyanate, the contents of the separable flask were reacted at 180°C for 2 hours. After the reaction, the contents of the separable flask were cooled to 50°C. After cooling, 2.6 g (0.0122 mol) of trimesic acid (1,3,5-benzenetricarboxylic acid) was supplied to a separable flask. Following the supply of trimesic acid, the contents of the separable flask were reacted at 160°C for 1 hour.

[0145] The above reaction yielded a polyamide-imide NMP solution. The number-average molecular weight of the polyamide-imide was 30,500. The solid content in the NMP solution (varnish) was 34% by mass. After reprecipitation of the solids in a mixture of the NMP solution and methanol, the precipitate in the mixture was filtered off. The filtered precipitate was dried in a vacuum dryer for 24 hours. By grinding the dried precipitate, polyamide-imide powder was obtained.

[0146] In the preparation of the compound in Example 3, the above-mentioned polyamide-imide (PAI) and epoxy resin were used as thermosetting resins. The epoxy resin used in Example 3 is YX-4000H manufactured by Mitsubishi Chemical Corporation. TM The following was used: YX-4000H TM It is a biphenyl-type epoxy resin. The curing accelerator used in Example 3 was 2E4MZ manufactured by Shikoku Chemicals Co., Ltd.TM The following was used: 2E4MZ TM This is an imidazole-based curing accelerator (2-ethyl-4-methylimidazole). The mass of polyamide-imide (PAI) in the compound of Example 3 is shown in Table 1 below. YX-4000H in the compound of Example 3 TM The mass is shown in Table 1 below. 2E4MZ in the compound of Example 3 TM The mass is shown in Table 1 below. Except for the matters mentioned above, the compound, molded body, and anisotropic bonded magnet of Example 3 were prepared in the same manner as in Example 1. The Br and crush strength of the anisotropic bonded magnet of Example 3 were measured in the same manner as in Example 1. The measurement results for Example 3 are shown in Table 1 below.

[0147] (Example 4) The mass of the magnetic powder in the compound of Example 4 is shown in Table 1 below. KIR-30 in the compound of Example 4 TM The mass is shown in Table 1 below. C17Z in the compound of Example 4 TM The mass is shown in Table 1 below. The compound of Example 4 was prepared in the same manner as in Example 1, except for the points mentioned above. Tablets made from the compound of Example 4 were produced by compression molding of the compound at 100 MPa. In the supply process of Example 4, tablets made from the compound were supplied into the mold of the molding apparatus instead of the compound (powder). Except for the above, the molded body and anisotropic bonded magnet of Example 4 were manufactured in the same manner as in Example 1. The Br and crush strength of the anisotropic bonded magnet of Example 4 were measured in the same manner as in Example 1. The measurement results for Example 4 are shown in Table 1 below.

[0148] (Example 5) In Example 5, epoxy resin and phenol novolac resin were used as thermosetting resins. The epoxy resin used in Example 5 is YX-4000H. TM The following was used. As the phenol novolac resin in Example 5, HP-850N manufactured by Showa Denko Materials Co., Ltd. was used. TM It was used. The curing accelerator used in Example 5 was PX-4PB manufactured by Nippon Chemical Industrial Co., Ltd. TM The PX-4PB was used. TM is tetra(n-butyl)phosphonium tetraphenylborate (Bu4P + B(Ph)4 - ) YX-4000H in the compound of Example 5 TM The mass is shown in Table 1 below. HP-850N in the compound of Example 5 TM The mass is shown in Table 1 below. PX-4PB in the compound of Example 5 TM The mass is shown in Table 1 below. Licowax E in the compound of Example 5 TM The mass is shown in Table 1 below. The (M2 / M1) × 100 for Example 5 is shown in Table 1 below. Except for the matters mentioned above, the compound, molded body, and anisotropic bonded magnet of Example 5 were prepared in the same manner as in Example 1. The Br and crush strength of the anisotropic bonded magnet of Example 5 were measured in the same manner as in Example 1. The measurement results for Example 5 are shown in Table 1 below.

[0149] (Examples 6-8, Comparative Examples 1 and 2) Licowax E in the compounds of Examples 6-8 and Comparative Examples 1 and 2 TM The mass is shown in Table 1 below. The (M2 / M1) × 100 values ​​for Examples 6-8 and Comparative Examples 1 and 2 are shown in Table 1 below. Except for the matters mentioned above, the compounds, molded articles, and anisotropic bonded magnets of Examples 6-8 and Comparative Examples 1 and 2 were prepared in the same manner as in Example 1. The Br and crush strength of the anisotropic bonded magnets of Examples 6-8 and Comparative Examples 1 and 2 were measured in the same manner as in Example 1. The measurement results for Examples 6-8 and Comparative Examples 1 and 2 are shown in Table 1 below.

[0150] [Table 1] [Industrial applicability]

[0151] For example, according to one aspect of the present invention, an anisotropic bonded magnet with excellent residual magnetic flux density and mechanical strength is provided. [Explanation of symbols]

[0152] 2...Compound, 2A...Molded body, 2B...Anisotropic bonded magnet, 3...Magnetic particles (magnetic powder), 4...Wax, 5...Thermosetting resin (resin composition), 6...Clearance, 10...Manufacturing equipment (molding equipment), c1...First coil, c2...Second coil, d1...Die, H...Magnetic field, m...Magnification direction of magnetic particles, M...Magnification direction of anisotropic bonded magnet, p1...First punch, p2...Second punch.

Claims

1. A compound comprising magnetic powder, thermosetting resin, and wax, The aforementioned magnet powder includes an Sm-Fe-N permanent magnet. The sum of the mass of the magnetic powder and the mass of the thermosetting resin is represented as M1. The mass of the wax is represented as M2, (M2 / M1) × 100 is between 2 and 10, Used as a raw material for anisotropic bonded magnets, Compound.

2. The thermosetting resin comprises at least one resin selected from the group consisting of epoxy resins, maleimide compounds, polyimides, polyamides, and polyamideimides. The compound according to claim 1.

3. The aforementioned wax contains montanic acid ester, The compound according to claim 1.

4. A compound comprising the compound according to any one of claims 1 to 3, tablet.

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