Magnetic foreign matter separation device, magnetic foreign matter separation method, and method for producing resin composition for sealing

Abstract

To provide a magnetic foreign matter separation device for efficiently removing a magnetic foreign matter from a mixture of the magnetic foreign matter and a non-magnetic material.SOLUTION: A magnetic foreign matter separation device includes: a separation tank; an agitation member which is arranged inside the separation tank, and has a support member having a rotary shaft and an agitation blade provided on a side face of the support member; and a first magnet which is arranged below in a gravity direction to the support member in a rotary shaft extension direction of the support member, inside the separation tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a magnetic foreign matter separation device, a magnetic foreign matter separation method, and a method for producing an encapsulating resin composition. [Background technology]

[0002] In semiconductor packaging, the insulating performance of non-conductive materials used in electronic components or their substrates, such as non-conductive encapsulants, thermally conductive sheets, and heat-dissipating fillers, can be degraded by the presence of conductive foreign matter, primarily iron, contained in the raw materials. For example, the presence of conductive foreign matter can cause quality assurance issues, such as short circuits between element circuits. Because the circuit width of semiconductor elements is often extremely narrow, it is necessary to remove as many conductive foreign matter, even if they are very small, as they can electrically bridge the circuit.

[0003] Since most conductive foreign matter is a magnetic conductor whose main component is iron, and most non-conductive materials are non-magnetic, a method of separating them using magnetism is effective for removing them. Patent document 1 discloses a capture device that captures magnetic metal foreign matter contained in a liquid by flowing the liquid containing magnetic metal foreign matter from top to bottom along an inclined surface while bringing the liquid into contact with the surface of a magnet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-005397 Summary of the Invention [Problem to be solved by the invention]

[0005] In particular, in recent years, as semiconductor packages have become smaller and more sophisticated, the pitch between wirings and between elements has become narrower. In order to efficiently obtain an encapsulating resin composition that suppresses short-circuit defects in wirings, etc., even in such semiconductor packages, a method for efficiently removing magnetic foreign matter from a mixture of magnetic foreign matter and a non-magnetic material is desired. An object of one embodiment of the present disclosure is to provide a magnetic foreign matter separation device and a magnetic foreign matter separation method that efficiently remove magnetic foreign matter from a mixture of magnetic foreign matter and a non-magnetic material. Another aspect of the present disclosure has an object to provide a method for producing an encapsulating resin composition that can provide an encapsulating resin composition that suppresses short-circuit defects in wiring. [Means for solving the problem]

[0006] Specific means for achieving the above object include the following aspects. <1> A separation tank; a stirring member disposed inside the separation tank, the stirring member having a support member with a rotating shaft and a stirring blade provided on a side surface of the support member; a first magnet disposed inside the separation tank below the support member in the direction of gravity in the extension direction of the rotation axis of the support member; A magnetic foreign matter separation device having the above structure. <2> Further comprising a second magnet arranged radially outside the support member inside the separation tank. <1> The magnetic foreign matter separation device according to claim 1. <3> The first magnet is cylindrical and has magnetic force on its side. <1> or <2> The magnetic foreign matter separation device according to claim 1. <4> a dispersion liquid containing a material containing magnetic foreign matter and a dispersion medium, <1> ~ <3> supplying the magnetic foreign matter separating device described in any one of the above to the separation tank; agitating the dispersion with the agitator to separate the magnetic foreign matter from the dispersion; A magnetic foreign matter separation method comprising: <5> a dispersion liquid containing an inorganic filler containing magnetic foreign matter and a dispersion medium, <1> ~ <3> supplying the magnetic foreign matter separating device described in any one of the above to the separation tank; agitating the dispersion with the agitator to separate the magnetic foreign matter from the dispersion, thereby obtaining a dispersion of the purified inorganic filler; mixing the purified inorganic filler with a resin; A method for producing an encapsulating resin composition, comprising: <6> a dispersion liquid containing magnetic foreign matter, an inorganic filler, a resin, and a dispersion medium, <1> ~ <3> supplying the magnetic foreign matter separating device described in any one of the above to the separation tank; agitating the dispersion with the agitator to separate the magnetic foreign matter from the dispersion and obtain a purified dispersion; removing the dispersion medium from the purified dispersion; A method for producing an encapsulating resin composition, comprising: [Effects of the Invention]

[0007] According to one aspect of the present disclosure, there is provided a magnetic foreign matter separation device and a magnetic foreign matter separation method that efficiently remove magnetic foreign matter from a mixture of magnetic foreign matter and a non-magnetic material. According to another aspect of the present disclosure, there is provided a method for producing an encapsulating resin composition that can provide an encapsulating resin composition that suppresses short-circuit defects in wiring. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram illustrating an example of a magnetic foreign matter separation device according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the present disclosure, numerical ranges indicated using "to" include the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Also, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with the value shown in the test examples. When embodiments of the present disclosure are described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to these.

[0010] Hereinafter, embodiments for carrying out the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, components (including element steps, etc.) are not essential unless otherwise specified. The same applies to numerical values ​​and their ranges, and do not limit the present disclosure.

[0011] [Magnetic foreign matter separation device and magnetic foreign matter separation method] A magnetic foreign matter separation device (hereinafter simply referred to as a "separation device") in one embodiment of the present disclosure comprises a separation tank, a stirring member arranged inside the separation tank and having a support member with a rotating shaft and a stirring blade provided on the side of the support member, and a first magnet arranged inside the separation tank below the support member in the direction of gravity in the extension direction of the rotating shaft of the support member. Hereinafter, the lower side of the support member in the direction of gravity relative to the support member in the extension direction of the rotation axis of the support member inside the separation tank will also be referred to as the "specific position." The separation device may further include a second magnet disposed radially outside the support member inside the separation tank, as required.

[0012] A magnetic foreign matter separation method (hereinafter also referred to simply as "separation method") in one embodiment of the present disclosure includes supplying a dispersion liquid containing a material containing magnetic foreign matter and a dispersion medium to a separation tank of the separation device, and separating the magnetic foreign matter from the dispersion liquid by stirring the dispersion liquid with a stirring member.

[0013] The separation device and separation method described above use a separation tank that has an agitator disposed therein and a first magnet disposed at a specific position, so that magnetic contaminants are efficiently removed from a mixture of magnetic contaminants and non-magnetic materials for the following reasons. In the separation device and separation method described above, the rotation of the agitator causes the dispersion to flow inside the separation tank, but there are localized areas where the flow velocity is low. When a simulation was performed on the flow of the dispersion, it was found that there is an area where there is almost no flow at a specific position below the direction of gravity in the extension direction of the rotation axis of the support member. If a magnet is placed in an area with a high flow rate, magnetic foreign matter that approaches the magnet may be pushed away from the magnet by the flow of the dispersion liquid, making it difficult for the magnet to capture it. In contrast, in the separation device and separation method described above, the magnet is placed in a specific position where there is an area with almost no flow. Therefore, it is thought that when magnetic foreign matter with a high specific gravity rides the flow of the dispersion liquid and reaches the specific position, it will settle due to gravity and be attracted by magnetic force and captured by the magnet. Hereinafter, examples of the separation device and separation method of the present disclosure will be described with reference to the drawings, but the separation device and separation method of the present disclosure are not limited to these.

[0014] FIG. 1 is a schematic configuration diagram illustrating an example of a separation device according to an embodiment of the present disclosure. 1 includes a separation tank 12 and an agitator 14 disposed inside the separation tank 12. The agitator 14 includes a support member 16 having a rotation axis A and an agitator blade 18 provided on the side of the support member 16. Inside the separation tank 12, a first magnet 20 is disposed below the direction of arrow G, which is the direction of gravity relative to the support member 16, in the extension direction of the rotation axis of the support member 16, i.e., at a specific position.

[0015] In addition to the first magnet 20, a second magnet 22 is disposed inside the separation tank 12 of the separation device 10 at a position radially outside the support member 16 and close to the side surface of the separation tank 12. The separation tank 12 also has, at its upper part, a supply unit 24A connected to one end of a supply path 24 that supplies the separation tank 12 with a dispersion D containing a material containing magnetic foreign matter and a dispersion medium, and a discharge unit 26A connected to one end of a discharge path 26 that discharges the dispersion D from the separation tank 12 from which at least a portion of the magnetic foreign matter has been removed.

[0016] In the separation method using the separator 10, first, the dispersion D is supplied to the separation tank 12 from the supply section 24A through the supply path 24. The dispersion D supplied to the inside of the separation tank 12 is stirred by the stirring member 14. Specifically, the stirring blades 18 rotate around the support member 16, causing the dispersion D to flow inside the separation tank 12. When magnetic foreign matter with a high specific gravity contained in the dispersion D enters a specific position, which is a region where there is almost no local flow, it settles due to gravity and is attracted by the magnetic force generated by the first magnet 20 and captured by the first magnet 20. Then, the dispersion D from which at least a portion of the magnetic foreign matter has been removed is discharged from the separation tank 12 through the discharge passage 26 from the discharge portion 26A. The separation method using the separator 10 may be a batch method or a continuous method.

[0017] In the separation device 10 of this embodiment, the first magnet 20 is positioned at a specific position, i.e., below the direction of arrow G, which is the direction of gravity relative to the support member 16, in the extension direction of the rotation axis of the support member 16, thereby efficiently removing magnetic foreign matter from the dispersion liquid D.

[0018] (separation tank) In the separation device 10 of this embodiment, the separation tank 12 is cylindrical, but the shape of the separation tank is not limited to this. From the viewpoint of efficiently removing magnetic foreign matter, the shape of the separation tank is preferably cylindrical, and more preferably circular. When the separation tank 12 is cylindrical, the flow of the dispersion D is less likely to be impeded, and the difference in flow rate of the dispersion D between the vicinity of the stirring blade 18 and the specific position is large, making it easier for the magnetic foreign matter to be selectively captured by the first magnet 20, and thus the magnetic foreign matter is thought to be efficiently removed. The material of the separation tank 12 is not particularly limited, and examples thereof include materials that have low reactivity with the supplied dispersion D, and specific examples thereof include glass, metals such as SUS, and resins such as polypropylene.

[0019] In the separation device 10 of this embodiment, the bottom surface of the separation tank 12 is not flat but is conical with a specific central position protruding downward, but the shape of the bottom surface of the separation tank is not limited to this. The bottom surface of the separation tank may be flat or may have a shape that protrudes upward or downward. From the perspective of efficiently removing magnetic foreign matter, the shape of the bottom surface of the separation tank is preferably a shape that protrudes downward at a specific position, and more preferably a conical shape with the specific position protruding downward. It is believed that by having a separation tank with a conical bottom surface with a specific position protruding downward, magnetic foreign matter tends to collect at a specific position on the bottom surface and is easily captured by the first magnet 20, thereby increasing the efficiency of removing magnetic foreign matter. The upper surface of separation tank 12 may be closed with a lid or may be open. The pressure inside separation tank 12 may be, for example, atmospheric pressure.

[0020] (Agitating member) In the separation device 10 of this embodiment, the agitator 14 is provided at a position where the rotation axis A of the support member 16 passes through the center of the bottom surface of the separation tank 12, but the position of the agitator 14 is not limited to this. From the viewpoint of efficiently removing magnetic foreign matter, it is preferable that the rotation axis A passes through a position close to the center of the bottom surface of the separation tank 12. By providing the agitator 14 at a position where the rotation axis A passes through the center of the bottom surface of the separation tank 12, the flow of the dispersion D is less likely to be impeded, and the difference in flow rate of the dispersion D between near the agitator blade 18 and the specific position is large, which is thought to make it easier for the magnetic foreign matter to be selectively captured by the first magnet 20.

[0021] In the separation device 10 of this embodiment, the agitator 14 is disposed so that the rotation axis A of the support member 16 is parallel to the direction of arrow G, which is the direction of gravity, but the angle of the rotation axis A with respect to the direction of gravity is not limited to this. From the viewpoint of efficiently removing magnetic foreign matter, when the direction of gravity is defined as 0 degrees, the angle of the rotation axis A with respect to the direction of gravity is preferably 45 degrees or less, more preferably 20 degrees or less, and even more preferably 5 degrees or less. It is believed that the smaller the angle of the rotation axis A with respect to the direction of gravity, the more easily magnetic foreign matter that reaches a specific position will settle due to gravity and be efficiently captured by the first magnet 20.

[0022] The shape of the support member 16 is not particularly limited, but a columnar shape is preferable, and a cylindrical shape is more preferable. The maximum diameter of the cross section of the support member 16 perpendicular to the rotation axis A is not particularly limited, and may be, for example, 1 cm to 10 cm, and is preferably 1 cm to 3 cm from the viewpoint of efficiently removing magnetic foreign matter. The material of the support member 16 is not particularly limited, and examples thereof include materials that have low reactivity with the dispersion D supplied to the separation tank 12, and specific examples thereof include glass, metals such as SUS, and resins such as polypropylene.

[0023] In the separation device 10 of this embodiment, the agitating blades 18 are provided in two stages, one near the bottom of the separation tank 12 and the other at the vertical center of the separation tank 12, but the positions and number of stages of the agitating blades 18 are not limited to these. From the viewpoint of efficiently removing magnetic foreign matter, it is preferable that the agitating blades 18 are provided at least at the vertical center of the separation tank 12. The number of stages of the agitating blades 18 may be, for example, one to five stages, and from the viewpoint of efficiently removing magnetic foreign matter, two to three stages are preferred. The shape of the stirring blade 18 is not particularly limited, and examples thereof include a flat paddle type, an inclined paddle type, and a propeller type. The maximum length from the end of the stirring blade 18 to the rotation axis A of the support member 16 is not particularly limited, and may be a length that does not come into contact with the magnet 22. The material of the stirring blade 18 is not particularly limited, and examples thereof include materials that have low reactivity with the dispersion D supplied to the separation tank 12, and specific examples thereof include glass, metals such as SUS, and resins such as polypropylene.

[0024] As described above, in the separation device 10 of this embodiment, it is believed that the efficiency of removing magnetic contaminants is increased by the generation of an area with almost no flow on the lower side in the direction of gravity in the extension direction of the rotation axis of the support member 16. For this reason, it is preferable that the lower end of the support member 16 in the direction of gravity is spaced apart from the bottom surface of the separation tank 12. The shortest distance from the lower end of the support member 16 in the direction of gravity to the bottom surface of the separation tank 12 is, for example, 5 cm to 15 cm, and from the viewpoint of efficiently removing magnetic contaminants, 5 cm to 10 cm is preferable.

[0025] The rotation speed of the stirring member 14 is selected depending on the viscosity of the dispersion D to be separated, and may be in the range of 50 rpm to 500 rpm, for example. When the separation method is a batch method, the rotation time of the stirring member 14 in one operation is not particularly limited, and may be in the range of, for example, 1 minute to 1 hour.

[0026] (magnet) The type of magnet used as the first magnet 20 and the second magnet 22 is not particularly limited, and examples include permanent magnets such as ferrite magnets, neodymium magnets, and alnico magnets, electromagnets, etc. From the viewpoint of magnetic force, neodymium magnets are preferred. From the viewpoint of ease of installation, the shape of the magnets used as the first magnet 20 and the second magnet 22 is preferably columnar. Examples of the shape of the columnar magnet include a cylindrical shape and a rectangular columnar shape, and a cylindrical shape is preferred from the viewpoint of efficiently removing magnetic foreign matter. The magnetic flux strength per unit area of ​​the magnets used as the first magnet 20 and the second magnet 22 is not particularly limited, and may be, for example, 0.05 T or more, and from the viewpoint of efficiently removing magnetic foreign matter, 1 T to 2 T is preferable.

[0027] When first magnet 20 is a cylindrical magnet, it is preferable that the height direction of the magnet is nearly parallel to rotation axis A and that the side surface of the magnet is a magnetic pole surface. By having the side surface of the magnet be a magnetic pole surface, it is thought that magnetic foreign matter that has flowed from an area close to the side surface of separation tank 12 to a specific position along the bottom surface of separation tank 12 can be efficiently captured. The maximum height of first magnet 20 from the bottom surface of separation tank 12 is, for example, 3 cm to 20 cm, and from the viewpoint of efficiently removing magnetic foreign matter, 5 cm to 15 cm is preferable. Note that, in separation device 10, first magnet 20 is provided in contact with the bottom surface of separation tank 12, but this is not limiting, and first magnet 20 may be provided at a position separated from the bottom surface via a support stand or the like. The maximum diameter of the cross section perpendicular to the height direction of the first magnet 20 is, for example, 1 cm to 5 cm, and from the viewpoint of efficiently removing magnetic foreign matter, 2 cm to 5 cm is preferable. The shortest distance from the first magnet 20 to the support member 16 is, for example, 1 cm to 5 cm, and from the viewpoint of efficiently removing magnetic foreign matter, 1 cm to 3 cm is preferable.

[0028] When second magnet 22 is a cylindrical magnet, it is preferable that the height direction of the magnet is nearly parallel to rotation axis A and that the side surface of the magnet is a magnetic pole surface. By using magnetic pole surfaces as the side surfaces of the magnet, magnetic foreign matter that has flowed into the area near the side surface of separation tank 12 can be efficiently captured. The height of second magnet 22 is, for example, 0.3 to 0.95 times the height of the side surface of separation tank 12, and from the viewpoint of efficiently removing magnetic foreign matter, preferably 0.5 to 0.95 times. The maximum diameter of the cross section of second magnet 22 perpendicular to the height is, for example, 1 cm to 5 cm, and from the viewpoint of efficiently removing magnetic foreign matter, preferably 2 cm to 5 cm. In the separation device 10 of this embodiment, second magnets 22 are arranged inside the separation tank 12, but this is not limited to this and second magnets 22 may not be arranged. Furthermore, in the separation device 10 of this embodiment, six second magnets 22 are arranged at equal intervals, but the number of second magnets 22 arranged inside the separation tank 12 is not limited to this. The number of second magnets 22 may be, for example, 0 to 6, and from the viewpoint of efficiently removing magnetic foreign matter, 1 to 6 is preferable.

[0029] (supply section and discharge section) In the separation apparatus 10 of this embodiment, as described above, one end of the supply channel 24 is connected to the supply section 24A at the top of the separation tank 12, and one end of the discharge channel 26 is connected to the discharge section 26A at the bottom of the separation tank 12. Therefore, in both the batch separation method and the continuous separation method, the supply of the dispersion D and the discharge of the dispersion D from which at least a portion of the magnetic foreign matter has been removed are easy, and operability is good.

[0030] The location of the supply unit 24A is not particularly limited, and is preferably located at the top of the separation tank 12 from the viewpoint of ease of supplying the dispersion D. The supply unit 24A may be located on the top or side of the separation tank 12 within the upper part of the separation tank 12, preferably on the top surface, and more preferably at a position on the top surface away from the support member 16 from the viewpoint of not interfering with the rotation of the stirring member 14. The number of supply units 24A may be one or more. The supply unit 24A may be configured such that the supply channel 24 is not connected to the supply unit 24. Alternatively, the separation tank 12 may not have a specific supply unit 24A, and the dispersion D may be supplied from an open portion where the entire top surface is open.

[0031] The location of the discharge unit 26A is not particularly limited, and is preferably located at the bottom of the separation tank 12 from the viewpoint of ease of discharging the dispersion D from which at least a portion of the magnetic foreign matter has been removed. The discharge unit 26A may be located on the bottom or side of the separation tank 12 in the lower part of the separation tank 12, preferably on the bottom, and more preferably on the bottom at a position away from the first magnet 20 from the viewpoint of improving the efficiency of capturing the magnetic foreign matter by the first magnet 20. The number of discharge units 26A may be one or more. The discharge unit 26A may be configured such that the discharge path 26 is not connected to the discharge unit 26. Furthermore, when the separation method is a batch method, the separation tank 12 may not have a specific discharge unit 26A, and the dispersion D from which at least a portion of the magnetic foreign matter has been removed may be discharged from an open portion where the entire top surface of the separation tank 12 is open.

[0032] When the separation method is a batch method, the amount of dispersion D supplied in one operation is not particularly limited, and may be in the range of 0.5 L to 100 L, for example. When the separation method is continuous, the amount of dispersion D supplied from the supply unit 24A per hour is not particularly limited, and may be in the range of 1 L / hour to 100 L / hour, for example.

[0033] (Dispersion liquid) Dispersion D is a dispersion medium in which a material containing magnetic foreign matter is dispersed. The dispersion medium may be, for example, a liquid medium, and is not particularly limited as long as it can be stirred inside the separation tank 12, and is selected depending on the type of material to be separated. Examples of the dispersion medium as a liquid medium include water, organic solvents, and mixtures thereof. Examples of organic solvents include alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and isopropyl alcohol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; aromatic hydrocarbons such as benzene, toluene, and xylene; and aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane. The viscosity of the dispersion medium at 25° C. is, for example, 0.5 mPa·s to 100 mPa·s, and from the viewpoint of separation efficiency, it is preferably 0.5 mPa·s to 10 mPa·s, and more preferably 0.5 mPa·s to 5 mPa·s.

[0034] The content of the dispersion medium in Dispersion D is, for example, 10% to 80% by mass relative to the entire Dispersion D, and from the viewpoint of separation efficiency, 20% to 70% by mass is preferable, and 40% to 65% by mass is more preferable. The temperature of the dispersion D supplied to the separation tank 12 may be in the range of 0°C to 60°C, for example.

[0035] (Application) The separation device and separation method of the present disclosure are used to separate and remove magnetic foreign matter from non-magnetic material in which the magnetic foreign matter has been mixed. Examples of materials that can be subjected to the separation operation include powders, and specific examples include ceramic powders used in ceramics for insulating substrates, non-conductive shields, heat dissipation insulators, abrasive grains, polishing agents, etc., resin-based powder materials, carbon materials, fibers, etc. More specifically, examples of materials containing magnetic foreign matter include inorganic particles used as inorganic fillers contained in sealing materials that seal elements in electronic component devices, sealing material particles produced using the inorganic particles, graphite particles used in producing negative electrode materials for lithium ion secondary batteries, etc. Examples of the inorganic particles include silica particles, alumina particles, titania particles, glass particles, calcium carbonate particles, zirconium silicate particles, calcium silicate particles, silicon nitride particles, aluminum nitride particles, boron nitride particles, zirconia particles, etc.

[0036] Examples of magnetic foreign matter to be separated and removed include magnetic powders of steel, pure iron, iron oxide, stainless steel, nickel, cobalt, and the like. The number-average particle size of the magnetic foreign matter is, for example, 100 μm or less, and may be 75 μm or less. The number-average particle size of the magnetic foreign matter can be determined by measuring the collected magnetic foreign matter with a laser scattering diffraction particle size distribution measuring device.

[0037] Dispersion D may contain other components as required in addition to the material containing magnetic foreign matter and the dispersion medium. Specific examples of a method for producing an encapsulating resin composition using the separation device and separation method of the present embodiment will be described below, but the separation device, separation method, and method for producing an encapsulating resin composition are not limited to these.

[0038] [Method of manufacturing encapsulating resin composition] The method for producing an encapsulating resin composition according to an embodiment of the present disclosure is carried out using the separation device and separation method described above.

[0039] First Embodiment The method for producing an encapsulating resin composition according to the first embodiment includes a dispersion supplying step of supplying a dispersion containing an inorganic filler containing magnetic foreign matter and a dispersion medium to a separation tank of the separation device described above, a separation step of stirring the dispersion with a stirring member to separate the magnetic foreign matter from the dispersion and obtain a dispersion of a purified inorganic filler, and a mixing step of mixing the purified inorganic filler with a resin. In the first embodiment, by applying the above-described separation device and the above-described separation method, an encapsulating resin composition that suppresses short-circuit defects in wiring can be obtained.

[0040] In the first embodiment, an inorganic filler containing magnetic foreign matter is used as the material to be separated, and the inorganic filler containing magnetic foreign matter is mixed with a dispersion medium to obtain a dispersion liquid. The dispersion liquid used in the dispersion liquid supplying step only needs to contain at least the inorganic filler containing magnetic foreign matter and the dispersion medium, and may contain other components as necessary. In the separation step, the magnetic foreign matter is removed from the dispersion by the separation method using the separation device described above, to obtain a dispersion of the purified inorganic filler. The details of the separation device and separation method are also as described above.

[0041] In the mixing step, the purified inorganic filler from which at least a portion of the magnetic foreign matter has been removed in the separation step is mixed with a resin. In the mixing step, the dispersion of the purified inorganic filler obtained in the separation step may be used as is as the purified inorganic filler to be mixed with the resin, or the purified inorganic filler obtained by removing the dispersion medium from the dispersion may be used. Methods for removing the dispersion medium include filtration, heating, decompression, and combinations thereof. In the mixing step, other components may be further mixed with the purified inorganic filler and the resin as needed. Examples of other components include components other than the inorganic filler and resin that constitute the encapsulating resin composition, specifically, for example, a curing agent, a curing accelerator, a release agent, and a colorant, as well as other additives that are commonly used as materials for encapsulating resin compositions. Details of each component that constitutes the encapsulating resin composition will be described later.

[0042] In the first embodiment, examples of the method for producing the encapsulating resin composition through the dispersion supplying step, the separating step, and the mixing step include the spraying method described below, as well as a kneading and pulverizing method, a microwave heating and drying method, etc. Among these, from the viewpoint of obtaining an encapsulating resin composition in which the inclusion of magnetic foreign matter is suppressed, it is preferable to produce the encapsulating resin composition by the spraying method.

[0043] (spray method) In the spraying method, the encapsulating resin composition is produced through a spraying step of spraying a mixture containing at least an inorganic filler, a resin, and a dispersion medium, and a drying step of drying the sprayed mixture. When the spraying method is applied in the first embodiment, the mixture is obtained by mixing the purified inorganic filler obtained in the separation step with a resin or the like in the mixing step. In the mixing step, a resin and, if necessary, other components may be added to the dispersion of the purified inorganic filler obtained in the separation step, or another dispersion medium, a resin and, if necessary, other components may be added to the purified inorganic filler from which the dispersion medium has been removed.

[0044] The dispersion medium contained in the mixture is not particularly limited as long as it can dissolve or disperse the purified inorganic filler and the raw materials including the resin. For example, from the viewpoint of low environmental impact and ease of dissolving the raw materials, it may be at least one selected from the group consisting of hydrocarbons, esters, ketones, and alcohols. From the viewpoint of low volatility at room temperature (25°C) and ease of removal during drying, the dispersion medium may be at least one selected from the group consisting of benzene, toluene, cyclohexanone, acetone, methyl ethyl ketone, and methyl isobutyl ketone (MIBK). The dispersion medium may be used alone or in combination of two or more.

[0045] The content of the dispersion medium in the mixture is not particularly limited. In the subsequent spraying step, it is preferable to appropriately adjust the viscosity of the mixture so as to obtain particles of the desired size. Therefore, it is also preferable to appropriately adjust the content of the dispersion medium in the mixture according to the desired viscosity of the mixture. Specifically, the content of the dispersion medium in the mixture is preferably 10% by mass to 90% by mass. When the content of the dispersion medium is 10% by mass or more, the viscosity of the mixture is appropriately controlled, making it easier to spray, and when it is 90% by mass or less, the energy required to dry and remove the dispersion medium can be reduced, resulting in excellent productivity. The content of the dispersion medium in the mixture is more preferably 20% by mass to 70% by mass. When the content of the dispersion medium is 20% by mass to 70% by mass, spray stability and productivity tend to be better.

[0046] The viscosity of the mixture at 25°C is preferably 0.001 Pa·s to 50 Pa·s, and more preferably 1 Pa·s to 30 Pa·s. When the viscosity of the mixture at 25°C is 0.001 Pa·s or more, separation of the inorganic filler and the resin after spraying is suppressed, and the resulting encapsulating resin composition tends to have excellent fluidity when encapsulating. When the viscosity of the mixture at 25°C is 50 Pa·s or less, the spray stability tends to be excellent. In the present disclosure, the viscosity of the mixture is measured using an E-type viscometer or a B-type viscometer at 25° C. and a rotation speed of 20 to 60 revolutions per minute (rpm).

[0047] The method for mixing the raw materials and the dispersion medium is not particularly limited, and mixing may be performed using a mixer. Examples of mixers include a stirring mixer using a stirring blade, a three-roll mill, a twin-screw continuous kneader, a planetary mixer, a static mixer, and a planetary mixer. It is preferable to appropriately set the stirring time and stirring speed.

[0048] The mixture obtained above is sprayed and dried. As a result, a particulate encapsulating resin composition is obtained. The spraying step and the drying step may be independent steps, but it is preferable to dry while spraying. As a method for drying while spraying, a method using a spray dryer can be mentioned.

[0049] In a spray dryer, the mixture (slurry) is sprayed vertically from above into a suitably heated dry air stream. This removes the dispersion medium from the mixture, yielding solid granules. The dry air stream may be air, nitrogen gas, or the like. Methods of spraying in a spray dryer include the nozzle method and the disk method.

[0050] In the spray dryer, it is preferable to appropriately set the inlet temperature and outlet temperature from the viewpoint of adjusting the particle size of the encapsulating resin composition, removing the dispersion medium, etc. The inlet temperature and outlet temperature can be appropriately adjusted depending on the types, concentrations, etc. of the raw materials and dispersion medium. It is also preferable to appropriately set the spray rate. The spray rate can also be appropriately adjusted depending on the types, concentrations, etc. of the raw materials and dispersion medium.

[0051] In the spraying and drying steps, the slurry may be heated before spraying to facilitate removal of the dispersion medium. The heating temperature can be appropriately set, for example, to 30°C or higher, 35°C or higher, or 40°C or higher. In order to prevent the dispersion medium from volatilizing in the material storage container, the slurry may be cooled before spraying. The cooling temperature can be appropriately set, for example, to 23°C or less, or 20°C or less.

[0052] The granulated encapsulating resin composition falls due to gravity and is collected by a cyclone, a bag filter, or the like from the vertically lower portion of the spray dryer. The entire amount of the particulate encapsulating resin composition may be collected in a bag filter without using a cyclone. The removed dispersion medium may also be collected by a condenser.

[0053] The volume average particle diameter of the granulated encapsulating resin composition is preferably 100 μm to 3 mm, more preferably 200 μm to 1 mm, and even more preferably 220 μm to 1 mm. When the volume average particle diameter is 100 μm or more, the collection efficiency is improved and the fluidity when encapsulating with the obtained encapsulating resin composition tends to be excellent. When the volume average particle diameter is 3 mm or less, the appearance defect during tablet molding tends to be suppressed. The granulated encapsulating resin composition may be amorphous secondary aggregates formed by further agglomeration of amorphous primary aggregates each consisting of several particles of inorganic filler.

[0054] In the present disclosure, the volume average particle size of the encapsulating resin composition is measured by a laser diffraction method, and can be measured using a laser diffraction scattering particle size distribution measuring device (for example, LS230 manufactured by Beckman Coulter, Inc.).

[0055] The particulate encapsulating resin composition recovered from the spray dryer may be further subjected to a sieving process to classify the particles. In the sieving process, a sieve such as a vibrating sieve may be used. In the sieving process, at least one of coarse powder and fine powder may be removed depending on the semiconductor device to which the composition is applied.

[0056] The particulate encapsulating resin composition may be used for encapsulating a semiconductor element as it is, or may be formed into tablets and then used for encapsulating a semiconductor element. The tableting may be carried out by a general method used for encapsulating materials.

[0057] The maximum particle size of the magnetic foreign matter in the obtained encapsulating resin composition is preferably 75 μm or less, more preferably 45 μm or less, from the viewpoint of suppressing short-circuit defects in wiring.

[0058] Second Embodiment The method for producing an encapsulating resin composition according to the second embodiment includes a dispersion supplying step of supplying a dispersion containing magnetic foreign matter, an inorganic filler, a resin, and a dispersion medium to a separation tank of the separation device described above, a separation step of stirring the dispersion with a stirring member to separate the magnetic foreign matter from the dispersion and obtain a purified dispersion, and a dispersion medium removal step of removing the dispersion medium from the purified dispersion. In the second embodiment, by applying the above-described separation device and the above-described separation method, an encapsulating resin composition that suppresses short-circuit defects in wiring can be obtained.

[0059] The material to be separated in the second embodiment may be an inorganic filler containing magnetic foreign matter, a resin containing magnetic foreign matter, a resin composition containing magnetic foreign matter, an inorganic filler, and a resin, or a combination thereof. In the second embodiment, a dispersion is obtained by mixing the material to be separated with a dispersion medium. The dispersion used in the dispersion supplying step preferably contains at least magnetic foreign matter, an inorganic filler, a resin, and a dispersion medium, and may further contain other components contained in the encapsulating resin composition as needed. In the dispersion used in the dispersion supplying step, the resin may be dissolved in the dispersion medium or may be dispersed in the dispersion medium in a solid state. Details of each component constituting the encapsulating resin composition will be described later. In the separation step, the magnetic foreign matter is removed from the dispersion by the separation method using the separation device described above, to obtain a purified dispersion. The details of the separation device and separation method are also as described above.

[0060] In the dispersion medium removing step, the dispersion medium is removed from the purified dispersion. Examples of the method for removing the dispersion medium include filtration, heating, decompression, and a combination thereof. In order to obtain an encapsulating resin composition of a desired size and shape, the dispersion may be formed into droplets before the dispersion medium removing step, for example, by a spraying method described later, or pulverization or the like may be performed after the dispersion medium removing step. Furthermore, other components contained in the encapsulating resin composition may be added as needed to the purified dispersion obtained in the separation step, and then the dispersion medium removal step may be carried out.

[0061] In the second embodiment, examples of the method for producing an encapsulating resin composition through the dispersion liquid supplying step, the separating step, and the dispersion medium removing step include the above-mentioned spraying method, microwave heating drying method, etc. Among these, from the viewpoint of obtaining an encapsulating resin composition in which the inclusion of magnetic foreign matter is suppressed, it is preferable to produce the encapsulating resin composition by the spraying method.

[0062] As described above, in the spraying method, the encapsulating resin composition is produced through a spraying step of spraying a mixture containing at least an inorganic filler, a resin, and a dispersion medium, and a drying step of drying the sprayed mixture. When the spraying method is applied in the second embodiment, the mixture may be a purified dispersion obtained in the separation step, or may be a purified dispersion to which other components contained in the encapsulating resin composition have been added as needed. Details of the dispersion medium contained in the mixture, the spraying step, the drying step, and the encapsulating resin composition obtained by the spraying method are as described above.

[0063] <Components Constituting the Encapsulating Resin Composition> (Inorganic filler) Examples of inorganic fillers include inorganic materials such as fused silica, crystalline silica, glass, alumina, calcium carbonate, zirconium silicate, calcium silicate, silicon nitride, aluminum nitride, boron nitride, magnesium oxide, silicon carbide, beryllia, zirconia, zircon, fosterite, steatite, spinel, mullite, titania, talc, clay, and mica.

[0064] The shape of the inorganic filler is not particularly limited, and examples thereof include powder, spheres, fibers, etc., with spherical shapes being preferred from the viewpoints of filling properties and reducing wear of the sealing mold. As the inorganic filler, spherical fused silica particles, crushed silica particles, etc. are preferred.

[0065] The inorganic filler may be used alone or in combination of two or more. The term "use of two or more inorganic fillers" refers to, for example, the use of two or more inorganic fillers having the same components but different average particle sizes, the use of two or more inorganic fillers having the same average particle size but different components, and the use of two or more inorganic fillers having different average particle sizes and types.

[0066] The content of the inorganic filler is not particularly limited, but from the viewpoint of further improving the properties of the cured product after encapsulation, such as the thermal expansion coefficient, thermal conductivity, and elastic modulus, the content of the inorganic filler is preferably 70% by mass to 95% by mass, and more preferably 75% by mass to 90% by mass, of the entire encapsulating resin composition.

[0067] The content of inorganic filler in the encapsulating resin composition is measured as follows. First, the total mass of the cured product (molded product) of the inorganic filler is measured, and the molded product is baked at 400°C for 2 hours and then at 700°C for 3 hours to evaporate the resin component, and the mass of the remaining inorganic filler is measured. From each of the obtained masses, the ratio of the mass of the inorganic filler to the total mass of the encapsulating resin composition is calculated, and this is defined as the content of the inorganic filler.

[0068] The average particle diameter of the inorganic filler is not particularly limited. For example, the volume average particle diameter of the inorganic filler is preferably 0.1 μm to 150 μm, and more preferably 0.5 μm to 75 μm. The volume average particle diameter of the inorganic filler can be measured as the particle diameter (D50) at which the cumulative total from the small diameter side reaches 50% in the volume-based particle size distribution measured using a laser scattering diffraction particle size distribution analyzer.

[0069] (resin) The resin is preferably a thermosetting resin. The thermosetting resin is not particularly limited, and examples thereof include epoxy resin, unsaturated polyester resin, polyamide resin, polyamideimide resin, phenol resin, melamine resin, etc., and from the viewpoint of sealing properties, it is preferable to include an epoxy resin. As the epoxy resin, those commonly used as sealing materials can be appropriately used.

[0070] Specific examples of epoxy resins include novolac epoxy resins (phenol novolac epoxy resins, orthocresol novolac epoxy resins, etc.) obtained by epoxidizing novolac resins obtained by condensing or co-condensing, under an acidic catalyst, at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, etc., and naphthol compounds such as α-naphthol, β-naphthol, dihydroxynaphthalene, etc., with an aliphatic aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, etc.; triphenylmethane epoxy resins obtained by epoxidizing triphenylmethane phenolic resins obtained by condensing or co-condensing, under an acidic catalyst, the above-mentioned phenolic compound with an aromatic aldehyde compound such as benzaldehyde, salicylaldehyde, etc.; and novolac resins obtained by co-condensing, under an acidic catalyst, the above-mentioned phenolic compound and naphthol compound with an aldehyde compound. diphenylmethane-type epoxy resins, which are diglycidyl ethers of bisphenol A, bisphenol F, etc.; biphenyl-type epoxy resins, which are diglycidyl ethers of alkyl-substituted or unsubstituted biphenols; stilbene-type epoxy resins, which are diglycidyl ethers of stilbene-based phenolic compounds; sulfur-containing epoxy resins, which are diglycidyl ethers of bisphenol S, etc.; epoxy resins, which are glycidyl ethers of alcohols such as butanediol, polyethylene glycol, and polypropylene glycol; glycidyl ester-type epoxy resins, which are glycidyl esters of polycarboxylic acids such as phthalic acid, isophthalic acid, and tetrahydrophthalic acid; glycidylamine-type epoxy resins, in which the active hydrogen bonded to the nitrogen atom of aniline, diaminodiphenylmethane, isocyanuric acid, etc. is substituted with a glycidyl group; and dicyclopentadiene-type epoxy resins, which are epoxidized co-condensation resins of dicyclopentadiene and phenolic compounds.Alicyclic epoxy resins such as vinylcyclohexene diepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 2-(3,4-epoxy)cyclohexyl-5,5-spiro(3,4-epoxy)cyclohexane-m-dioxane, which are produced by epoxidizing the olefin bonds in the molecule; paraxylylene-modified epoxy resins, which are glycidyl ethers of paraxylylene-modified phenolic resins; metaxylylene-modified epoxy resins, which are glycidyl ethers of metaxylylene-modified phenolic resins; terpene-modified epoxy resins, which are glycidyl ethers of terpene-modified phenolic resins; and dicyclopentadiene-modified phenolic resins, which are glycidyl ethers of dicyclopentadiene-modified phenolic resins. Examples of suitable epoxy resins include pentadiene-modified epoxy resins, cyclopentadiene-modified epoxy resins which are glycidyl ethers of cyclopentadiene-modified phenolic resins, polycyclic aromatic ring-modified epoxy resins which are glycidyl ethers of polycyclic aromatic ring-modified phenolic resins, naphthalene-type epoxy resins which are glycidyl ethers of naphthalene ring-containing phenolic resins, halogenated phenol novolac-type epoxy resins, hydroquinone-type epoxy resins, trimethylolpropane-type epoxy resins, linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid, and aralkyl-type epoxy resins obtained by epoxidizing aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins. Further examples of suitable epoxy resins include epoxidized silicone resins and epoxidized acrylic resins.

[0071] (hardening agent) The curing agent is not particularly limited, and those commonly used as encapsulating materials can be appropriately applied. For example, when an epoxy resin is used as the thermosetting resin, examples of the curing agent include phenolic curing agents, amine curing agents, acid anhydride curing agents, polymercaptan curing agents, polyaminoamide curing agents, isocyanate curing agents, and blocked isocyanate curing agents. From the viewpoint of improving heat resistance, the curing agent is preferably one having a phenolic hydroxyl group in the molecule (phenolic curing agent). When a phenolic curing agent is used, the tolerance range for temperature control in the spraying process and drying process is wide, and the resulting particulate encapsulating resin composition tends to have excellent uniformity in particle size, particle shape, etc.

[0072] Specific examples of phenolic curing agents include polyhydric phenolic compounds such as resorcinol, catechol, bisphenol A, bisphenol F, and substituted or unsubstituted biphenols; novolak-type phenolic resins obtained by condensing or co-condensing at least one phenolic compound selected from the group consisting of phenolic compounds such as phenol, cresol, xylenol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol, and naphthol compounds such as α-naphthol, β-naphthol, and dihydroxynaphthalene, with an aldehyde compound such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and salicylaldehyde, under an acidic catalyst; and copolymers of the above phenolic compounds with dimethoxyparaxylene, bis(methoxymethyl)bis(benzoyl)methyl ... phenyl, etc.; aralkyl-type phenolic resins such as phenol aralkyl resins and naphthol aralkyl resins synthesized from phenyl, etc.; paraxylylene and / or metaxylylene-modified phenolic resins; melamine-modified phenolic resins; terpene-modified phenolic resins; dicyclopentadiene-type phenolic resins and dicyclopentadiene-type naphthol resins synthesized by copolymerization of the above-mentioned phenolic compounds with dicyclopentadiene; cyclopentadiene-modified phenolic resins; polycyclic aromatic ring-modified phenolic resins; biphenyl-type phenolic resins; triphenylmethane-type phenolic resins obtained by condensing or co-condensing the above-mentioned phenolic compounds with aromatic aldehyde compounds such as benzaldehyde and salicylaldehyde in the presence of an acid catalyst; and phenolic resins obtained by copolymerizing two or more of these. The curing agent may be used alone or in combination of two or more.

[0073] When an epoxy resin is used as the curable resin and a curing agent is contained in the resulting encapsulating resin composition, the equivalent ratio of the epoxy resin to the curing agent, i.e., the ratio of the number of functional groups in the curing agent to the number of epoxy groups in the epoxy resin (number of functional groups in the curing agent / number of epoxy groups in the epoxy resin), is not particularly limited. In order to minimize the amount of unreacted components, the equivalent ratio is preferably set in the range of 0.5 to 2.0, more preferably in the range of 0.7 to 1.2.

[0074] (curing accelerator) The curing accelerator is not particularly limited, and any accelerator generally used as a sealing material can be used as appropriate. Examples of the curing accelerator include diazabicycloalkenes such as 1,5-diazabicyclo[4.3.0]nonene-5 (DBN) and 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), cyclic amidine compounds such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, and 2-heptadecylimidazole; derivatives of the cyclic amidine compounds; phenol novolac salts of the cyclic amidine compounds or their derivatives; and combinations of these compounds with maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone, 1,4- quinone compounds such as naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone; compounds with intramolecular polarization obtained by adding compounds with π bonds such as diazophenylmethane; cyclic alkyl groups such as tetraphenylborate salt of DBU, tetraphenylborate salt of DBN, tetraphenylborate salt of 2-ethyl-4-methylimidazole, and tetraphenylborate salt of N-methylmorpholine; midinium compounds; tertiary amine compounds such as pyridine, triethylamine, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris(dimethylaminomethyl)phenol; derivatives of the above tertiary amine compounds; ammonium salt compounds such as tetra-n-butylammonium acetate, tetra-n-butylammonium phosphate, tetraethylammonium acetate, tetra-n-hexylammonium benzoate, and tetrapropylammonium hydroxide; tertiary phosphines such as triphenylphosphine, diphenyl(p-tolyl)phosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, tris(alkylalkoxyphenyl)phosphine, tris(dialkylphenyl)phosphine, tris(trialkylphenyl)phosphine, tris(tetraalkylphenyl)phosphine, tris(dialkoxyphenyl)phosphine, tris(trialkoxyphenyl)phosphine, tris(tetraalkoxyphenyl)phosphine, trialkylphosphine, dialkylarylphosphine, and alkyldiarylphosphine;Phosphine compounds such as complexes of the above-mentioned tertiary phosphines and organoborons; compounds having intramolecular polarization obtained by adding the above-mentioned tertiary phosphines or the above-mentioned phosphine compounds to maleic anhydride, quinone compounds such as 1,4-benzoquinone, 2,5-toluquinone, 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, and phenyl-1,4-benzoquinone, and compounds having a π bond such as diazophenylmethane; compounds having intramolecular polarization obtained by adding the above-mentioned tertiary phosphines or the above-mentioned phosphine compounds to 4-bromophenol, 3-bromophenol, 2-bromophenol, 4-chlorophenol, 3-chlorophenol, 2-chlorophenol, 4-iodophenol, and 3-iodophenol; Examples of compounds having intramolecular polarization include compounds obtained by reacting a halogenated phenol compound such as phenol, 2-iodophenol, 4-bromo-2-methylphenol, 4-bromo-3-methylphenol, 4-bromo-2,6-dimethylphenol, 4-bromo-3,5-dimethylphenol, 4-bromo-2,6-di-t-butylphenol, 4-chloro-1-naphthol, 1-bromo-2-naphthol, 6-bromo-2-naphthol, or 4-bromo-4'-hydroxybiphenyl, followed by a dehydrohalogenation step; tetra-substituted phosphonium compounds such as tetraphenylphosphonium compounds, tetra-substituted phosphonium compounds and tetra-substituted borates having no phenyl group bonded to the boron atom such as tetra-p-tolylborate, and salts of tetraphenylphosphonium compounds with phenol compounds. The curing accelerators may be used alone or in combination of two or more.

[0075] When a curing accelerator is contained in the encapsulating resin composition, the content of the curing accelerator is not particularly limited, and is preferably 0.1 mass % to 5.0 mass % relative to 100 parts by mass of the resin component (i.e., the total of the resin and the curing agent), and more preferably 0.15 mass % to 0.35 mass % in consideration of the fluidity of the encapsulating resin composition.

[0076] (mold release agent) The release agent is not particularly limited, and any agent generally used as a sealing material can be appropriately used. Specific examples of the release agent include carnauba wax, higher fatty acids such as montanic acid and stearic acid, higher fatty acid metal salts, ester waxes such as montanic acid esters, and polyolefin waxes such as oxidized polyethylene and non-oxidized polyethylene. The release agents may be used alone or in combination of two or more.

[0077] When a release agent is contained in the encapsulating resin composition, the content of the release agent is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, per 100 parts by mass of the resin component. When the content of the release agent is 0.01 part by mass or more per 100 parts by mass of the resin component, sufficient release properties tend to be obtained. When the content of the release agent is 10 parts by mass or less per 100 parts by mass of the resin component, better adhesion tends to be obtained. Furthermore, a mixture containing a release agent tends to be prevented from adhering to the inner wall of a drying tower during spray drying. Therefore, the use of a release agent tends to prevent foreign matter from being mixed in through the inner wall of the drying tower and also tends to improve yield. Furthermore, the inner wall of the drying tower may be coated with fluorine, silicone, or the like to prevent adhesion.

[0078] (coloring agent) The colorant is not particularly limited, and conventionally known colorants can be used. Examples of the colorant include carbon black, organic dyes, organic pigments, titanium oxide, red lead, and red iron oxide. The content of the colorant can be appropriately selected depending on the purpose, etc. The colorants may be used alone or in combination of two or more.

[0079] (Other additives) Examples of other additives include an ion exchanger, a flame retardant, a silane coupling agent, a stress relaxation agent, etc. The resulting encapsulating resin composition may contain, as necessary, various additives commonly used in the art.

[0080] The ion exchanger is not particularly limited, and conventionally known ion exchangers can be used, specifically, hydrotalcite compounds and hydrous oxides of at least one element selected from the group consisting of magnesium, aluminum, titanium, zirconium, and bismuth. The ion exchangers may be used alone or in combination of two or more.

[0081] When an ion exchanger is contained in the encapsulating resin composition, the content of the ion exchanger is not particularly limited as long as it is an amount sufficient to capture ions such as halogen ions, etc. For example, the content of the ion exchanger is preferably 0.1 to 30 parts by mass, and more preferably 1 to 10 parts by mass, per 100 parts by mass of the resin component.

[0082] The flame retardant is not particularly limited, and conventionally known flame retardants can be used, specifically, organic or inorganic compounds containing halogen atoms, antimony atoms, nitrogen atoms, or phosphorus atoms, metal hydroxides, etc. The flame retardants may be used alone or in combination of two or more.

[0083] The silane coupling agent is not particularly limited, and conventionally known ones can be used. Specifically, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, Examples of suitable silanes include γ-(β-aminoethyl)aminopropyldimethoxymethylsilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, methyltriethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, γ-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, and γ-mercaptopropylmethyldimethoxysilane. The silane coupling agents may be used alone or in combination of two or more.

[0084] The stress relaxation agent is not particularly limited, and conventionally known ones can be used. Specific examples include thermoplastic elastomers such as silicone-based, styrene-based, olefin-based, urethane-based, polyester-based, polyether-based, polyamide-based, and polybutadiene-based elastomers, rubber particles such as NR (natural rubber), NBR (acrylonitrile-butadiene rubber), acrylic rubber, urethane rubber, and silicone powder, and rubber particles having a core-shell structure such as methyl methacrylate-styrene-butadiene copolymer (MBS), methyl methacrylate-silicone copolymer, and methyl methacrylate-butyl acrylate copolymer. The stress relaxation agents may be used alone or in combination of two or more.

[0085] [Test example] The above embodiment will be specifically explained below using test examples, but the scope of the above embodiment is not limited to these test examples.

[0086] <Test example> (Test Example 1) As the separator A, a separator 10 shown in Fig. 1 was prepared. Details of the separator A are as follows. Separation tank 12: Material: SUS304, Inner diameter: 26 cm, Side height: 40 cm Support member 16: Shape: cylindrical, material: SUS304, diameter: 1.9 cm, shortest distance to the bottom of separation tank 12: 6 cm, angle of rotation axis relative to the direction of gravity: 0 degrees Mixing blade 18 (2 stages) ··· Material: SUS304, Shape: Inclined paddle blade, Maximum length from rotation axis A: 5.5 cm, First magnet 20: Type: neodymium magnet, Shape: cylindrical, Magnetic flux strength: 1.2 T, Sides are magnetic pole faces, Maximum height from bottom of separation tank 12: 11 cm, Diameter: 2.5 cm, Minimum distance to support member: 1 cm Second magnet 22 (6 pieces): Type: Neodymium magnet, Shape: Cylindrical, Magnetic flux strength: 1.2 T, Side is magnetic pole face, Height: 38 cm, Diameter: 2.5 cm, Minimum distance from rotation axis A: 10 cm

[0087] Dispersion D was prepared by mixing 310 g of silica powder and 500 mL of pure water, suspending the mixture, and stirring. The viscosity of pure water at 25°C is 0.89 mPa·s. The dispersion D was supplied to the separation tank 12 from the supply part 24A of the separation tank 12, and after rotating the stirring member 14 at a rotation speed of 300 rpm for 10 minutes, the dispersion D was discharged from the discharge part 26A of the separation tank 12. The pressure inside the separation tank 12 was normal pressure, and the temperature of the dispersion D was 25°C.

[0088] The discharged 500 mL of dispersion D was collected, passed through a magnet with a sheath tube, and the magnet was removed. The number and size of the attached magnetic foreign matter were confirmed using a microscope, and the diameter and number of the magnetic foreign matter contained in the collected dispersion D were determined. As a result, magnetic foreign matter of 45 μm or larger was successfully removed. The maximum particle size of the magnetic foreign matter in the resulting dispersion of purified silica was 40 μm.

[0089] From the above results, it can be seen that in Test Example 1, the amount of magnetic foreign matter that was not magnetically attracted by the separator and remained was small, and the magnetic foreign matter was efficiently removed. [Explanation of symbols]

[0090] 10 Separation device 12 Separation tank 14 Stirring member 16 Support member 18 Mixing blade 20 First Magnet 22 Second Magnet 24 Supply route 24A supply section 26 Exhaust channel 26A Discharge section A rotation axis D Dispersion G Gravity direction

Claims

1. A separation tank; a stirring member disposed inside the separation tank, the stirring member having a support member with a rotating shaft and a stirring blade provided on a side surface of the support member; a first magnet disposed inside the separation tank below the support member in the direction of gravity in the extension direction of the rotation axis of the support member; A magnetic foreign matter separation device having the above structure.

2. 2. The magnetic foreign matter separator according to claim 1, further comprising a second magnet disposed inside the separation tank radially outward of the support member.

3. 2. The magnetic foreign matter separator according to claim 1, wherein the first magnet is columnar and has magnetic force on its side surface.

4. Supplying a dispersion liquid containing a material containing magnetic foreign matter and a dispersion medium to the separation tank of the magnetic foreign matter separation device according to any one of claims 1 to 3; agitating the dispersion with the agitator to separate the magnetic foreign matter from the dispersion; A magnetic foreign matter separation method comprising:

5. Supplying a dispersion liquid containing an inorganic filler containing magnetic foreign matter and a dispersion medium to the separation tank of the magnetic foreign matter separator according to any one of claims 1 to 3; agitating the dispersion with the agitator to separate the magnetic foreign matter from the dispersion, thereby obtaining a dispersion of the purified inorganic filler; mixing the purified inorganic filler with a resin; A method for producing an encapsulating resin composition, comprising:

6. Supplying a dispersion liquid containing magnetic foreign matter, an inorganic filler, a resin, and a dispersion medium to the separation tank of the magnetic foreign matter separator according to any one of claims 1 to 3; agitating the dispersion with the agitator to separate the magnetic foreign matter from the dispersion and obtain a purified dispersion; removing the dispersion medium from the purified dispersion; A method for producing an encapsulating resin composition, comprising:

Images