WO2016117648A1 - 六角板状フェライト粉及びその製造方法、並びに該フェライト粉を用いた樹脂組成物及び成型体 - Google Patents
六角板状フェライト粉及びその製造方法、並びに該フェライト粉を用いた樹脂組成物及び成型体 Download PDFInfo
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Definitions
- the present invention relates to a hexagonal plate-like ferrite powder having a remanent magnetization and a coercive force larger than that of a spherical hard ferrite powder and having a specific frequency characteristic, and an inexpensive manufacturing method thereof. Furthermore, the present invention relates to a resin composition containing the ferrite powder and a molded body using the resin composition.
- oxide magnetic materials such as ferrite have been used as radio wave absorbers, particularly radio wave absorbers in a high frequency band.
- ferrite various hexagonal plate-like ferrites have been proposed as exhibiting particularly good characteristics.
- metallic materials are also used as materials that reflect electromagnetic waves.
- a radio wave absorber that stably exhibits an attenuation of 10 dB or more or even 15 dB or more near 75 GHz in a thin sheet having a thickness of 0.5 mm or less can be provided.
- Patent Document 2 Japanese Patent Laid-Open No. 2008-66364 discloses Ba x Zn y Fe z O 22 (1.5 ⁇ x ⁇ 2.2, 1.2 ⁇ y ⁇ 2.5, 11 ⁇ z ⁇ 13) and the like, and a magnetic powder for a radio wave absorber using a hexagonal ferrite powder.
- the imaginary part ⁇ ′′ of the complex permeability can be improved compared with the conventional method in the high frequency region of 1 GHz or more, particularly in the region of 3 to 6 GHz. It is described that, compared with the Y-type hexagonal ferrite having the composition, a radio wave absorber having a thinner wall thickness can obtain equivalent or higher radio wave absorption performance.
- Patent Document 3 Japanese Patent Application Laid-Open No. 2011-66430 includes an A component (one or more of an alkaline earth metal element and Pb), an M component (one or more of a metal element excluding divalent Fe), Fe, and oxygen.
- the imaginary part ⁇ ′′ of the complex permeability can be remarkably improved in a high frequency region of 1 GHz or more, particularly in a region of 3 to 6 GHz, which is the same as that obtained by the conventional manufacturing method. It is described that, compared with the Z-type hexagonal ferrite having a composition, a radio wave absorber having a thinner wall thickness can obtain equivalent or higher radio wave absorption performance.
- These hexagonal ferrites described in Patent Documents 1 to 3 specify the ferrite composition, the peak particle size of the particle size distribution, the volume ratio according to the particle size distribution, and the aspect ratio, thereby specifying a thin-walled electromagnetic wave absorbing performance when used as an electromagnetic wave absorber. And improvement of radio wave absorption performance.
- an object of the present invention is to provide a ferrite powder having a remanent magnetization and a coercive force larger than those of spherical hard ferrite particles and having a magnetic permeability ⁇ ′′ having a maximum value in a specific frequency band, a method for producing the same, and the ferrite powder. It is providing the resin composition containing this and the molded object using this resin composition.
- the present inventors have a constant composition, and the hexagonal plate ferrite powder has a larger residual magnetization and coercive force than the spherical hard ferrite particles.
- the magnetic permeability ⁇ ′′ has a maximum value in a specific frequency band and have arrived at the present invention.
- the ferrite particles mean individual particles or an aggregate having a certain particle size.
- the ferrite powder means an aggregate of the entire ferrite particles and includes an aggregate in which the ferrite powder is aggregated.
- the present invention provides a hexagonal plate-like ferrite powder characterized by containing 7.8 to 9% by weight of Sr, 61 to 65% by weight of Fe, and 0.1 to 0.65% by weight of Mg. Is.
- the hexagonal plate-like ferrite powder according to the present invention includes an aggregate in which the hexagonal plate-like ferrite powder is agglomerated.
- the hexagonal plate-like ferrite powder according to the present invention preferably has a minor axis length of 0.5 to 3 ⁇ m and an aspect ratio of 3.5 to 9.
- the hexagonal plate-like ferrite powder according to the present invention preferably has a volume average particle size of 3 to 20 ⁇ m.
- the hexagonal plate-like ferrite powder according to the present invention preferably has an eluted Cl content of 1 to 100 ppm.
- the present invention provides a resin composition containing 50 to 99.5% by weight of the hexagonal plate-like ferrite powder.
- the present invention provides a molded body formed by molding the above resin composition.
- the present invention provides a method for producing hexagonal plate-like ferrite particles, characterized in that Fe 2 O 3 , SrCO 3 and MgCl 2 are dry-mixed as raw materials and subjected to main firing as they are.
- the present invention provides a method for producing hexagonal plate-like ferrite particles, characterized in that the fired product obtained by the above-mentioned firing is wet-ground, washed, dehydrated and dried, and then heat-treated at 750 to 1050 ° C. To do.
- the ferrite powder according to the present invention has a hexagonal plate shape and a specific composition, the residual magnetization and the coercive force are larger than those of the spherical hard ferrite powder, and the permeability ⁇ ′′ is maximum in a specific frequency band. Therefore, when used as a filler in a resin molded body, the particles have a high orientation, and a resin molded body with a higher energy product than a spherical ferrite powder is obtained, as well as a resin having specific frequency characteristics.
- the ferrite powder does not corrode even when used for a long period of time in close contact with a metal material that reflects electromagnetic waves, and particularly when the metal material that reflects electromagnetic waves has magnetism, the ferrite powder Since a resin molded product using a magnet can be magnetized without using an adhesive, it can be suitably used.
- FIG. 1 is a graph showing the frequency dependence of the magnetic permeability ⁇ ′′ of Example 1, Example 6 and Comparative Example 1.
- the ferrite powder according to the present invention has a hexagonal plate shape as described above. For this reason, remanent magnetization and coercive force are larger than spherical hard ferrite powder. Further, as described above, the hexagonal plate-like ferrite powder according to the present invention includes an aggregate in which the ferrite powder is aggregated.
- the hexagonal plate-like ferrite powder according to the present invention preferably has a minor axis length of 0.5 to 3 ⁇ m and an aspect ratio of 3.5 to 9.
- the length and aspect ratio of the hexagonal plate ferrite powder in the short axis direction are in the above range, so that not only high orientation is obtained when used as a filler for resin moldings, but also high coercive force and residual magnetization. can get. If the length in the minor axis direction is less than 0.5 m, the bulk density of the ferrite powder itself increases, and therefore the upper limit of the filler filling amount tends to decrease.
- the length in the minor axis direction exceeds 3 ⁇ m, the residual magnetization and coercive force of the ferrite powder tend to be small, and desired magnetic characteristics cannot be obtained.
- the aspect ratio is less than 3.5, the orientation of the particles is inferior, so that when used as a filler, the magnetic properties and frequency properties of the resin molding may be inferior.
- the aspect ratio exceeds 9 the bulk density of the ferrite powder itself is increased, so that the upper limit of the filler filling amount tends to be lowered.
- the volume average particle size of the hexagonal plate-like ferrite powder according to the present invention is preferably 3 to 20 ⁇ m, and more preferably 3 to 12 ⁇ m.
- the volume average particle size is less than 3 ⁇ m, the viscosity of the resin composition tends to be high when ferrite powder is added as a filler to the resin, which may make it difficult to mold.
- a filler smaller than 3 ⁇ m is used in order to keep the viscosity at a certain level, it means that the amount of filler added must be reduced, and it becomes difficult to ensure a high filler filling amount. is doing.
- the volume average particle size exceeds 20 ⁇ m the viscosity of the resin composition tends to be low when ferrite powder is added to the resin as a filler, and it may be difficult to mold.
- volume average particle diameter (Microtrack): D 50 ) This volume average particle diameter is measured as follows. That is, it is measured using a Nikkiso Co., Ltd. Microtrac particle size analyzer (Model 9320-X100). Water was used as the dispersion medium. Place 10 g of sample and 80 ml of water in a 100 ml beaker and add 2 to 3 drops of dispersant (sodium hexametaphosphate). Next, using an ultrasonic homogenizer (UH-150 type, manufactured by SMT Co. LTD.), The output level was set to 4 and dispersion was performed for 20 seconds. Thereafter, bubbles formed on the beaker surface were removed, and the sample was put into the apparatus.
- dispersant sodium hexametaphosphate
- the hexagonal plate-like ferrite powder according to the present invention preferably has an eluted Cl content of 1 to 100 ppm, more preferably 1 to 50 ppm.
- the eluted Cl amount of the hexagonal plate ferrite powder is in the above range, even a resin molded body to which metal powder is added in addition to ferrite powder can be used in a stable state over a long period of time.
- the amount of eluted Cl is less than 1 ppm, Cl derived from impurities contained in the raw material cannot be completely removed.
- the amount of eluted Cl exceeds 100 ppm, when ferrite powder is used as the filler, the ferrite powder chlorine contained in the resin molded body is added to the resin molded body and the copper wiring around the resin molded body This causes corrosion of metal parts such as patterns.
- chlorine acts on a specific crystal plane of the ferrite crystal structure during the main firing, thereby promoting the growth of a crystal plane on which chlorine does not act. Therefore, ferrite powder containing a certain amount of chlorine can obtain a ferrite powder having a high aspect ratio, unlike ferrite powder containing no chlorine.
- the ferrite powder according to the present invention contains 7.8 to 9% by weight of Sr, 61 to 65% by weight of Fe, and 0.1 to 0.65% by weight of Mg.
- This composition makes it possible to have a remanent magnetization and a coercive force larger than those of spherical hard ferrite particles and to have a specific frequency characteristic of magnetic permeability ⁇ ′′.
- Mg is added in the above range, around 800 MHz is added.
- the peak position of the complex permeability ⁇ ′′ can be shifted, it is preferably used as a filler for an electromagnetic wave absorber used in a mobile phone.
- the Fe content may be relatively increased, and the residual magnetization and coercive force may be lowered. If the Sr content exceeds 9% by weight, the Fe content is relatively lowered, and the coercive force may not be sufficiently recovered by the heat treatment after the main firing. If the Fe content is less than 61% by weight, the coercive force may not be sufficiently recovered by the heat treatment after the main firing. If the Fe content exceeds 65% by weight, residual magnetization and coercive force may be lowered. If the Mg content is less than 0.1% by weight, the effect of addition cannot be expected and desired frequency characteristics cannot be obtained. If the Mg content exceeds 0.65% by weight, the residual magnetization and the coercive force may be lowered.
- Fe, Mg and Sr contents The contents of these Fe, Mg and Sr are measured as follows. A 0.2 g sample (ferrite powder) is weighed, and 60 ml of pure water plus 20 ml of 1N hydrochloric acid and 20 ml of 1N nitric acid is heated to prepare an aqueous solution in which the ferrite powder is completely dissolved. An ICP analyzer (Shimadzu) The contents of Fe, Mg and Sr were measured using ICPS-1000IV manufactured by Seisakusho.
- the remanent magnetization at 10K ⁇ 1000 / 4 ⁇ ⁇ A / m of the ferrite powder according to the present invention is preferably 27 to 37 Am 2 / kg and the coercive force is preferably 3000 to 4000 A / m.
- a vibrating sample magnetometer (model: VSM-C7-10A (manufactured by Toei Kogyo Co., Ltd.) was used. The measurement sample was packed in a cell having an inner diameter of 5 mm and a height of 2 mm and set in the apparatus. The measurement was performed by applying an applied magnetic field and sweeping to 10K ⁇ 1000 / 4 ⁇ ⁇ A / m. Next, the applied magnetic field was decreased to prepare a hysteresis curve. Saturation magnetization, residual magnetization, and coercive force were obtained from the data of this curve.
- the BET specific surface area of the hexagonal plate-like ferrite powder according to the present invention is preferably 0.3 to 0.85 m 2 / g, and more preferably 0.4 to 0.8 m 2 / g. By having such a BET specific surface area, it is possible to realize a high filling rate when it is used as a filler of a resin molded body because it has a high bulk density despite being a hexagonal plate.
- the particle size may be large and the particle shape may be indefinite rather than a hexagonal plate, and if it exceeds 0.85 m 2 / g, the ferrite particles Since it is too small and there is a possibility that the filling rate is lowered when used as a filler of a resin molding, it is not preferable.
- BET specific surface area was measured using a BET specific surface area measuring device (Macsorb HM model 1210) manufactured by Mountec Co., Ltd. The measurement sample is put in a vacuum dryer and treated at room temperature for 2 hours. Thereafter, the sample is filled so that the cells are dense, and set in the apparatus. The measurement was performed after pretreatment at a degassing temperature of 40 ° C. for 60 minutes.
- the resin composition according to the present invention contains 50 to 99.5% by weight of the hexagonal plate-like ferrite powder.
- content of the ferrite powder is less than 50% by weight, the ferrite characteristics cannot be sufficiently exhibited even if the ferrite powder is contained.
- content of a ferrite powder exceeds 99.5 weight%, since resin is hardly contained, there exists a possibility that it cannot shape
- the resin used in this resin composition examples include, but are not limited to, epoxy resins, phenol resins, melamine resins, urea resins, fluororesins and the like. Further, the resin composition contains a curing agent and a curing accelerator, and further contains various additives such as silica particles as necessary.
- the molded body according to the present invention can be obtained by molding and heat-curing a resin composition. And this molded object is used for uses, such as a general purpose bond magnet and LSI sealing agent for the purpose of electromagnetic wave absorption.
- Fe 2 O 3 , SrCO 3 and MgCl 2 are dry mixed as raw materials. Dry mixing is performed using a Henschel mixer or the like for 1 minute or longer, preferably 3 to 60 minutes for granulation.
- the granulated product thus obtained is subjected to main firing as it is without pre-firing.
- the main calcination is carried out in the atmosphere at 1150 to 1250 ° C. for 2 to 8 hours (peak) using a fixed electric furnace or the like to obtain hexagonal plate-like ferrite powder.
- the fired product obtained by the above-mentioned firing is wet pulverized with a bead mill or the like, washed, dehydrated, dried, and then heat treated at 750 to 1050 ° C. for 0.1 to 2 hours to obtain a heat treated hexagonal plate ferrite powder. good.
- the resin composition according to the present invention uses the above hexagonal plate-like ferrite powder and resin, a curing agent and a curing accelerator, and further, various additives such as silica particles as necessary, and a mixer such as a roll mill or a kneader. Are mixed to produce a resin composition.
- the manufacturing method of the molded object which concerns on this invention can be obtained by molding and heat-curing the resin composition.
- a doctor blade method, an extrusion method, a pressing method, a calendar roll method, or the like is used as the molding method.
- the heat curing may be either an external heating method or an internal heating method, and for example, a fixed or fluidized heating furnace, baking with microwaves, and resin curing with ultraviolet rays may be performed.
- Example 1 Fe 2 O 3 5.75 mol, SrCO 3 1 mol% and MgCl 2 .6H 2 O 0.1 mol were used as ferrite raw materials, and these were mixed and granulated with a Henschel mixer for 10 minutes.
- the obtained granulated product was subjected to main firing at 1200 ° C. for 4 hours (peak) in the air using a stationary electric furnace to obtain hexagonal plate-like ferrite powder.
- the fired product obtained in the main firing is wet pulverized with a bead mill at a solid content of 60% by weight for 30 minutes, washed, dehydrated, dried, and then heat treated at 950 ° C. for 1 hour in air. A finished hexagonal plate-like ferrite powder was obtained.
- Example 2 A hexagonal plate-like ferrite powder and a heat-treated hexagonal plate-like ferrite powder were produced in the same manner as in Example 1 except that the main firing temperature was 1150 ° C.
- Example 3 A hexagonal plate-like ferrite powder and a heat-treated hexagonal plate-like ferrite powder were prepared in the same manner as in Example 1 except that the main firing temperature was 1220 ° C.
- Example 4 Hexagonal plate-like ferrite powder and heat-treated hexagonal plate-like ferrite powder by the same method as in Example 1 except that Fe 2 O 3 6 mol, SrCO 3 1 mol% and MgCl 2 .6H 2 O 0.1 mol were used as ferrite raw materials. Was made.
- Example 5 Fe 2 O 3 5.65mol as ferrite material, SrCO 3 except for using 1 mol% and MgCl 2 ⁇ 6H 2 O 0.1mol, hexagonal plate-like ferrite powder and heat treated hex plate-shaped in the same manner of Example 1 Ferrite powder was produced.
- Example 6 Fe 2 O 3 5.75mol as ferrite material, SrCO 3 except for using 1 mol% and MgCl 2 ⁇ 6H 2 O 0.2mol, hexagonal plate-like ferrite powder and heat treated hex plate-shaped in the same manner of Example 1 Ferrite powder was produced.
- Example 7 Fe 2 O 3 5.75mol as ferrite material, SrCO 3 except for using 1 mol% and MgCl 2 ⁇ 6H 2 O 0.05mol, hexagonal plate-like ferrite powder and heat treated hex plate-shaped in the same manner of Example 1 Ferrite powder was produced.
- a hexagonal plate-like ferrite powder and a heat-treated hexagonal plate-like ferrite powder were prepared in the same manner as in Example 1 except that the heat treatment temperature was 900 ° C.
- Example 9 A hexagonal plate-like ferrite powder and a heat-treated hexagonal plate-like ferrite powder were prepared in the same manner as in Example 1 except that the heat treatment temperature was 1020 ° C.
- Example 4 A hexagonal plate-like ferrite powder and a heat-treated hexagonal plate-like ferrite powder were prepared in the same manner as in Example 1 except that the main firing temperature was 1050 ° C.
- grinding conditions apparatus, grinding time, solid content
- heat treatment conditions heat treatment atmosphere, heat treatment temperature, treatment time
- chemical analysis and magnetic characteristics saturation magnetization, residual magnetization
- the average particle diameter (D 10 , D 50 , D 90 ), BET specific surface area, particle shape (length in the minor axis direction, length in the major axis direction, aspect ratio) of Examples 1 to 9 and Comparative Examples 1 to 5 Ratio), and the evaluation of the obtained ferrite powder (frequency characteristics, pH 4 eluted chlorine amount before and after heat treatment, copper corrosion state) are shown in Table 3. Further, FIG. 1 shows the frequency dependence of the magnetic permeability ⁇ ′′ of Examples 1, 6 and Comparative Example 1.
- the volume average particle diameter D 10 and D 90 were measured according to D 50. Further, the frequency characteristics ( ⁇ ′′ peak position (MHz)) and the corrosion state of copper were performed as follows. Other measurement methods are as described above.
- the frequency characteristics of the complex permeability were measured as follows. Measurement was performed using an E4991A type RF impedance / material analyzer 16454A magnetic material measuring electrode manufactured by Agilent Technologies.
- complex permeability measurement sample Preparation of a complex permeability frequency characteristic measurement sample (hereinafter simply referred to as “complex permeability measurement sample”) is as follows. That is, 1 g of binder resin (Kynar 301F: polyvinylidene fluoride) is weighed into 9 g of the composite magnetic powder for noise suppression, placed in a 50 cc glass bottle, and stirred and mixed for 30 minutes in a 100 rpm ball mill.
- binder resin Kynar 301F: polyvinylidene fluoride
- the ferrite powders obtained in Examples 1 to 9 have a hexagonal plate shape, show desired high values of remanent magnetization and coercive force, and satisfy the eluted chlorine. Therefore, copper corrosion did not occur.
- Comparative Example 1 showed low values of residual magnetization and coercive force. Comparative Example 2 also showed a low coercive force value and a large amount of eluted chlorine, so that copper was slightly corroded.
- Comparative Example 3 not only showed a low coercive force, but also had an irregular shape.
- Comparative Example 4 the magnetic properties (saturation magnetization, residual magnetization, coercive force) all showed low values.
- Comparative Example 5 showed low values of remanent magnetization and coercive force, and an irregular shape.
- Example 10 The ferrite powder described in Example 1 was molded into a columnar magnetic property measurement sample having a diameter of 5 mm and a height of 3 mm in the same manner as the permeability measurement sample, and magnetic properties (saturation magnetization, residual magnetization, coercivity) ) was measured.
- the saturation magnetization is 51.21 (Am 2 / kg)
- the residual magnetization is 27.08 (Am 2 / kg)
- the coercive force is 2261 (A / m), which is sufficient to bring the magnetic metal into close contact with the magnetic force. It was confirmed that a strong magnetic force was obtained.
- the ferrite powder according to the present invention has a specific composition with a hexagonal plate shape, the residual magnetization and coercive force are larger than that of the spherical hard ferrite powder, and the permeability ⁇ ”in each frequency band is a specific value.
- a molded resin product having specific frequency characteristics can be obtained by further molding, and using the hexagonal plate-like ferrite powder as a filler.
- a resin molded body having a higher energy product than the spherical ferrite powder can be obtained. Therefore, this resin molding is suitably used as a radio wave absorber in each frequency band.
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Abstract
Description
<本発明に係る六角板状フェライト粉>
後述する透磁率・誘電率測定用サンプルの断面を研磨してフェライト粉の断面を日本電子社製JSM-6060Aを用い、加速電圧は20kVとし、キャリアSEMを450倍視野にて撮影した。その画像情報を、インターフェースを介してメディアサイバネティクス社製画像解析ソフト(Image-Pro PLUS)に導入して、板状粒子の長軸方向と短軸方向の長さを1粒子ごとに計測し、アスペクト比(=長軸方向の長さ/短軸方向の長さ)を算出したのち、100粒子の平均値を粒子の短軸方向の長さとアスペクト比とした。
この体積平均粒径は、次のようにして測定される。すなわち、日機装株式会社製マイクロトラック粒度分析計(Model9320-X100)を用いて測定される。分散媒には水を用いた。試料10gと水80mlを100mlのビーカーに入れ、分散剤(ヘキサメタリン酸ナトリウム)を2~3滴添加する。次いで超音波ホモジナイザー(SMT.Co.LTD.製UH-150型)を用い、出力レベル4に設定し、20秒間分散を行った。その後、ビーカー表面にできた泡を取り除き、試料を装置へ投入した。
[Cl濃度:溶出法]
(1)試料を50.000g+0.0002g以内に正確に秤り、150mlガラス瓶に入れる。
(2)フタル酸塩(pH4.01)50mlをガラス瓶に添加する。
(3)イオン強度調整剤、1mlをガラス瓶に続けて添加し、蓋を閉める。
(4)ペイントシェ-カ-にて10分間撹拌する。
(5)150mlガラス瓶の底に磁石を当てキャリアが落ちないように注意しながらNo.5Bの濾紙を用いてPP製(50ml)の容器にろ過する。
(6)得られた上澄み液を、pHメーターにて電圧を測定する。
(7)同様に、検量線用に作成したCl濃度別の溶液(純水、1ppm、10ppm、100ppm及び1000ppm)を測定し、それらの値から、サンプルのCl溶出量を計算する。
これらFe、Mg及びSrの含有量は、下記によって測定される。
試料(フェライト粉)0.2gを秤量し、純水60mlに1Nの塩酸20ml及び1Nの硝酸20mlを加えたものを加熱し、フェライト粉を完全溶解させた水溶液を準備し、ICP分析装置(島津製作所製ICPS-1000IV)を用いてFe、Mg及びSrの含有量を測定した。
振動試料型磁気測定装置(型式:VSM-C7-10A(東英工業社製))を用いた。測定試料は、内径5mm、高さ2mmのセルに詰めて上記装置にセットした。測定は、印加磁場を加え、10K・1000/4π・A/mまで掃引した。次いで、印加磁場を減少させ、ヒステリシスカーブを作製した。このカーブのデータより飽和磁化、残留磁化及び保磁力を求めた。
ここで、BET比表面積は、株式会社マウンテック製BET比表面積測定装置(Macsorb HM model 1210)を用いて測定を行った。測定試料を真空乾燥機に入れ、常温で2時間処理を行う。その後、試料をセルが密になるように充填し、装置にセットする。脱気温度40℃にて60分間前処理を行った後、測定を行った。
本発明に係る樹脂組成物は、上記六角板状フェライト粉を50~99.5重量%含有する。フェライト粉の含有量が50重量%を下回ると、フェライト粉を含有していてもフェライトの特性を十分発揮することができない。また、フェライト粉の含有量が99.5重量%を超える場合は、樹脂をほとんど含有していないため、成型できない可能性がある。
本発明に係る成型体は、樹脂組成物を成型、加熱硬化することにより得られる。そして、この成型体は、汎用のボンド磁石や電磁波吸収を目的としたLSI用封止剤等の用途に使用される。
本発明に係るフェライト粉の製造方法について説明する。
本発明に係る樹脂組成物は、上記六角板状フェライト粉と樹脂、硬化剤及び硬化促進剤、さらには必要に応じてシリカ粒子等の各種添加剤を加え、ロールミル、ニーダ等の混合機を用いて混合し、樹脂組成物が製造される。
本発明に係る成型体は、上記樹脂組成物を成型及び加熱硬化することにより得られる。成型法としては、ドクターブレード法、押し出し法、プレス法、カレンダーロール法等が用いられる。また、加熱硬化は、外部加熱方式又は内部加熱方式のいずれでもよく、例えば固定式又は流動式加熱炉、もしくはマイクロウェーブによる焼き付け、および、紫外線による樹脂硬化を行ってもよい。また、金型等を使用して加熱しながら加圧成型してもよい。
フェライト原料としてFe2O3 5.75mol、SrCO3 1mol%及びMgCl2・6H2O 0.1molを用い、これらをヘンシェルミキサーで10分混合、造粒した。
本焼成温度を1150℃とした以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
本焼成温度を1220℃とした以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
フェライト原料としてFe2O3 6mol、SrCO3 1mol%及びMgCl2・6H2O 0.1molを用いた以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
フェライト原料としてFe2O3 5.65mol、SrCO3 1mol%及びMgCl2・6H2O 0.1molを用いた以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
フェライト原料としてFe2O3 5.75mol、SrCO3 1mol%及びMgCl2・6H2O 0.2molを用いた以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
フェライト原料としてFe2O3 5.75mol、SrCO3 1mol%及びMgCl2・6H2O 0.05molを用いた以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
熱処理温度を1020℃とした以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
フェライト原料としてFe2O3 5.75mol、SrCO3 1mol%及びMgCl2・6H2O 0molを用いた以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
フェライト原料としてFe2O3 5.75mol、SrCO3 1mol%及びMgCl2・6H2O 0.3molを用いた以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
本焼成温度を1300℃とした以外は、実施例1の同様の方法でフェライト粉及び熱処理済フェライト粉を作製した。
本焼成温度を1050℃とした以外は、実施例1の同様の方法で六角板状フェライト粉及び熱処理済六角板状フェライト粉を作製した。
原料混合装置としてアトライター及びスプレードライヤーを用いた以外は、実施例1の同様の方法でフェライト粉及び熱処理済フェライト粉を作製した。
複素透磁率のの周波数特性の測定は下記のようにして行った。
アジレントテクノロジー社製E4991A型RFインピーダンス/マテリアル・アナライザ 16454A磁性材料測定電極を用いて測定した。
直径4cmの銅板の中心部にフェライト粉1gを乗せて上から1Kgの分銅を乗せて平らにしたのち、H/H環境下で2週間放置し、その後フェライト粉を取り除き銅の腐食状態について目視で確認した。
実施例1に記載のフェライト粉を透磁率測定用サンプルと同様の方法で直径5mm、高さ3mmの円柱状の磁気特性測定用のサンプルを成型し、磁気特性(飽和磁化、残留磁化、保磁力)を測定した。
従って、この樹脂成型体は、各周波帯域での電波吸収体として好適に用いられる。
Claims (9)
- Srを7.8~9重量%、Feを61~65重量%、Mgを0.1~0.65重量%含有することを特徴とする六角板状フェライト粉。
- 上記六角板状フェライト粉が凝集した凝集体である請求項1に記載の六角板状フェライト粉。
- 短軸方向の長さが0.5~3μm、アスペクト比が3.5~9である請求項1又は2に記載のフェライト粉。
- 体積平均粒径が3~20μmである請求項1~3のいずれかに記載のフェライト粉。
- 溶出Cl量が1~100ppmである請求項1~4のいずれかに記載のフェライト粉。
- 請求項1~5のいずれかに記載の六角板状フェライト粉を50~99.5重量%含有することを特徴とする樹脂組成物。
- 請求項6に記載の樹脂組成物を成型してなる成型体。
- 原料としてFe2O3、SrCO3及びMgCl2を乾式混合し、そのまま本焼成することを特徴とする六角板状フェライト粒子の製造方法。
- 請求項8に記載の本焼成で得られた焼成物を湿式粉砕し、洗浄、脱水、乾燥させた後、750~1050℃で熱処理を行うことを特徴とする六角板状フェライト粒子の製造方法。
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US15/544,626 US20180009677A1 (en) | 2015-01-22 | 2016-01-21 | Hexagonal plate shaped ferrite powder, manufacturing method thereof, and resin compound and molded product using the ferrite powder |
JP2016564288A JP6186639B2 (ja) | 2015-01-22 | 2016-01-21 | 六角板状フェライト粉及びその製造方法、並びに該フェライト粉を用いた樹脂組成物及び成型体 |
EP16740255.1A EP3248942B1 (en) | 2015-01-22 | 2016-01-21 | Resin composition containing a hexagonal plate shaped ferrite powder, manufacturing method thereof, and molded product formed from the resin composition |
KR1020177018676A KR102380236B1 (ko) | 2015-01-22 | 2016-01-21 | 육각판상 페라이트 분말 및 그 제조 방법, 그 페라이트 분말을 이용한 수지 조성물 및 성형체 |
CN201680004662.3A CN107406272B (zh) | 2015-01-22 | 2016-01-21 | 六方板状铁氧体粉及其制造方法、以及采用该铁氧体粉的树脂组合物及成形体 |
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WO2017170427A1 (ja) * | 2016-03-31 | 2017-10-05 | パウダーテック株式会社 | フェライト粉、樹脂組成物および成形体 |
WO2020230680A1 (ja) * | 2019-05-14 | 2020-11-19 | 富士フイルム株式会社 | 電波吸収体 |
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JP7262234B2 (ja) * | 2019-01-31 | 2023-04-21 | Dowaエレクトロニクス株式会社 | マグネトプランバイト型六方晶フェライト磁性粉末およびその製造方法 |
JP7323221B2 (ja) * | 2019-07-15 | 2023-08-08 | 漢陽大学校エリカ産学協力団 | 六角板状のフェライト構造体及びその製造方法 |
JPWO2021149794A1 (ja) * | 2020-01-24 | 2021-07-29 | ||
EP4098622A4 (en) * | 2020-01-27 | 2024-03-27 | Powdertech Co Ltd | FERRITE POWDER AND PRODUCTION PROCESS THEREOF |
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WO2020230680A1 (ja) * | 2019-05-14 | 2020-11-19 | 富士フイルム株式会社 | 電波吸収体 |
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EP3248942A1 (en) | 2017-11-29 |
KR20170106315A (ko) | 2017-09-20 |
EP3248942B1 (en) | 2021-03-03 |
TWI666661B (zh) | 2019-07-21 |
CN107406272B (zh) | 2020-02-18 |
KR102380236B1 (ko) | 2022-03-28 |
EP3248942A4 (en) | 2018-08-15 |
JP6186639B2 (ja) | 2017-08-30 |
TW201629996A (zh) | 2016-08-16 |
US20180009677A1 (en) | 2018-01-11 |
CN107406272A (zh) | 2017-11-28 |
JPWO2016117648A1 (ja) | 2017-04-27 |
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