JP6692707B2 - Microwave absorption heating element - Google Patents
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本発明は、電子レンジなどで使用される周波数の電磁波を吸収して優れた発熱性能を示す発熱体に関するものである。
かかる発熱体は、電子レンジ用発熱調理器や、マイクロ波を利用した保温材、温熱医療用発熱体など、産業用加熱用途に利用することができる。
TECHNICAL FIELD The present invention relates to a heating element that absorbs electromagnetic waves having a frequency used in a microwave oven or the like and exhibits excellent heating performance.
Such a heating element can be used for industrial heating applications such as a heating cooker for a microwave oven, a heat insulating material using microwaves, and a heating element for hot medical treatment.
電子レンジは、通常２．４５ＧＨｚのマイクロ波を食品に照射し、食品中の水分子がマイクロ波を吸収して振動する現象を利用して食品を加熱する調理機器である。ここで、マイクロ波を吸収できるのは水分子に限定されるものではなく、誘電損失や磁気損失の高い材料であれば、食品と同様にマイクロ波を吸収して温度が上昇することが知られている。 A microwave oven is a cooking device that heats foods by irradiating foods with microwaves of 2.45 GHz normally and utilizing the phenomenon that water molecules in the foods absorb and vibrate the microwaves. Here, it is known that microwaves are not limited to water molecules, and materials with high dielectric loss and magnetic loss can absorb microwaves and rise in temperature like foods. ing.
ここに、誘電損失を利用したマイクロ波吸収発熱体は、マイクロ波を吸収して高温まで温度が上昇し続けるため、安全に使用するためには、発熱粉の含有量を調整して放熱とのバランスを考慮する必要があった。 Here, the microwave absorption heating element utilizing the dielectric loss absorbs microwaves and the temperature continues to rise to a high temperature. I had to consider balance.
そこで、発明者らは、磁性体であるＭｎＺｎ系フェライトに注目して、マイクロ波を吸収して優れた発熱性能を示し、なおかつ、所定温度で昇温を停止するマイクロ波吸収発熱体用ＭｎＺｎ系フェライトを提案した（特許文献１参照）。 Therefore, the inventors have paid attention to MnZn-based ferrite, which is a magnetic material, to exhibit excellent heat generation performance by absorbing microwaves, and yet stop heating at a predetermined temperature. Ferrite has been proposed (see Patent Document 1).
特許文献１に記載の技術は、優れた昇温特性を有すると共に、キュリー温度で磁性体の磁気損失がなくなる性質を利用して所望の温度でその昇温を止めることができるという優れたものである。
The technique described in
そして、上記マイクロ波吸収発熱体用ＭｎＺｎ系フェライトは、出発原料であるＦｅ2Ｏ3や、ＺｎＯ、ＮｉＯ、ＭｎＯの組成比を調整することで、昇温停止温度を２００〜３００℃の温度範囲で制御することができる。 In the MnZn-based ferrite for microwave absorption heating element, by adjusting the composition ratio of starting materials Fe 2 O 3 , ZnO, NiO, and MnO, the temperature rise stop temperature is in the temperature range of 200 to 300 ° C. Can be controlled by.
また、発明者らは、３００℃より高温で昇温停止する必要がある場合に、ＮｉＺｎ系フェライトの組成比を調整することで、昇温停止温度を５５０℃までの広い範囲で制御することができる技術を提案している（特許文献２参照）。 Further, when it is necessary to stop the temperature increase at a temperature higher than 300 ° C., the inventors can control the temperature increase stop temperature in a wide range up to 550 ° C. by adjusting the composition ratio of NiZn ferrite. A possible technology is proposed (see Patent Document 2).
しかしながら、前記した技術では、単一系のフェライトを用いているため、異なる昇温停止温度のフェライト粉を作製するには、その都度、出発原料の配合比から変更して作製し直す必要があった。そのため、同じ手順（工程）を何度も繰り返さなければならず、生産効率の面で問題を残していた。 However, in the above-mentioned technique, since a single system ferrite is used, it is necessary to change the mixing ratio of the starting materials each time and re-produce it in order to produce the ferrite powder with different temperature rise and stop temperatures. It was Therefore, the same procedure (process) must be repeated many times, which leaves a problem in terms of production efficiency.
本発明は、上記の現状に鑑み開発されたもので、２つの系のフェライトを用いることで、従来以上に簡便な方法で、異なる昇温停止温度のフェライト粉を作り分け、所望の温度で昇温停止可能なマイクロ波吸収発熱体を得ることを目的とする。 The present invention has been developed in view of the above-mentioned situation, and by using two types of ferrites, ferrite powders having different temperature rising / stopping temperatures are separately produced in a simpler method than ever before, and elevated at a desired temperature. The object is to obtain a microwave absorption heating element capable of stopping the temperature.
発明者らは、上記した問題を解決するために、種々の組成よりなる、ＭｎＺｎ系フェライト粉とＮｉ系フェライト粉との昇温挙動を詳細に調べた。特に、組成の異なる複数のフェライト粉を混合して、その昇温挙動を調べたところ、所定の混合比範囲を選択すると、昇温速度および昇温停止温度が大きく変化する傾向にあることを見出した。 In order to solve the above-mentioned problems, the inventors have investigated in detail the temperature rising behavior of MnZn-based ferrite powder and Ni-based ferrite powder having various compositions. In particular, when a plurality of ferrite powders with different compositions were mixed and the temperature rise behavior was investigated, it was found that the temperature rise rate and temperature rise stop temperature tended to change significantly when a predetermined mixture ratio range was selected. It was
ついで、この知見に基づき、さらに、混合粉の昇温挙動を詳細に調べた結果、ＭｎＺｎ系フェライト粉と、Ｎｉ系フェライト粉という、２つの系のフェライトを所定の比率で混合することによって、出発原料の配合比から変更をして作製し直さなくても、所望の停止温度でその昇温が停止するだけでなく、立上りの昇温速度が速いマイクロ波吸収発熱体が得られることが分かり、本発明に至った。 Then, based on this finding, as a result of further detailed investigation of the temperature rise behavior of the mixed powder, it was found that two types of ferrite, MnZn-based ferrite powder and Ni-based ferrite powder, were mixed in a predetermined ratio, It was found that the microwave absorption heating element can be obtained not only by changing the blending ratio of the raw materials but not by remanufacturing, but by not only stopping the temperature rise at a desired stop temperature, but also by increasing the rising temperature rise rate The present invention has been reached.
すなわち、本発明の要旨構成は次のとおりである。
１．電磁波を吸収して発熱するＭｎＺｎ系フェライト粉と電磁波を吸収して発熱するＮｉ系フェライト粉とを、ＭｎＺｎ系フェライト粉：Ｎｉ系フェライト粉＝３０〜７０：３０〜７０（ｍａｓｓ％）の範囲で混合したマイクロ波吸収発熱体用フェライト粉を、樹脂中に３０〜９０（ｍａｓｓ％）の割合で含有させ、
前記ＭｎＺｎ系フェライト粉は、Ｆｅ酸化物（Ｆｅ 2 Ｏ 3 換算）：５３〜５７ｍｏｌ％、Ｚｎ酸化物（ＺｎＯ換算）：４〜１１ｍｏｌ％およびＮｉ酸化物（ＮｉＯ換算）：０〜４ｍｏｌ％を含み、残部がＭｎ酸化物からなり、
前記Ｎｉ系フェライト粉は、Ｆｅ酸化物（Ｆｅ 2 Ｏ 3 換算）：４６〜５１ｍｏｌ％、Ｃｕ酸化物（ＣｕＯ換算）：３〜１４ｍｏｌ％、Ｚｎ酸化物（ＺｎＯ換算）：０〜３８ｍｏｌ％を含み、残部がＮｉ酸化物からなることを特徴とするマイクロ波吸収発熱体。
That is, the gist of the present invention is as follows.
1. The MnZn-based ferrite powder that absorbs electromagnetic waves and generates heat and the Ni-based ferrite powder that absorbs electromagnetic waves and generates heat are mixed in the range of MnZn-based ferrite powder: Ni-based ferrite powder = 30 to 70 : 30 to 70 (mass%). The mixed ferrite powder for microwave absorption heating element is contained in the resin at a ratio of 30 to 90 (mass%) ,
The MnZn ferrite powder contains Fe oxide (Fe 2 O 3 conversion): 53 to 57 mol%, Zn oxide (ZnO conversion): 4 to 11 mol% and Ni oxide (NiO conversion): 0 to 4 mol%. , The balance consists of Mn oxide,
The Ni-based ferrite powder contains Fe oxide (Fe 2 O 3 conversion): 46 to 51 mol%, Cu oxide (CuO conversion): 3 to 14 mol%, Zn oxide (ZnO conversion): 0 to 38 mol%. A microwave absorbing heating element , the balance of which is made of Ni oxide .
本発明によれば、電子レンジの２．４５ＧＨｚのマイクロ波を効果的に吸収して発熱、昇温し、かつ、２００〜４００℃の温度範囲内で昇温を停止するマイクロ波吸収発熱体を、その都度、出発原料の配合比を変更して作製しなくても、特定組成のＭｎＺｎ系フェライト粉と、特定組成のＮｉ系フェライト粉との混合比を調整するだけで、簡便に作り分けることができる。
また、上記マイクロ波吸収発熱体は、単に混合物の混合比から比例計算した速度よりも、立上りの昇温速度を速くすることができる。
さらには、原料価格の高価なＮｉ系フェライトの一部を安価なＭｎＺｎ系フェライトで置き換えることができるため、製造コスト低減効果も期待できる。
ADVANTAGE OF THE INVENTION According to this invention, the microwave absorption heating element which absorbs effectively the microwave of 2.45 GHz of a microwave oven, heat | fever-generates and raises temperature, and stops temperature rise in a temperature range of 200-400 degreeC. , Each time, even if the mixing ratio of the starting raw materials is not changed, the MnZn-based ferrite powder of the specific composition and the Ni-based ferrite powder of the specific composition can be simply adjusted by adjusting the mixing ratio. You can
In addition, the microwave absorption heating element can increase the rising temperature rising speed more than the speed proportionally calculated from the mixing ratio of the mixture.
Further, since it is possible to replace a part of the expensive Ni-based ferrite having a low raw material price with an inexpensive MnZn-based ferrite, a manufacturing cost reduction effect can be expected.
以下、本発明を具体的に説明する。
本発明のマイクロ波吸収発熱体は、マイクロ波吸収発熱体用フェライト粉と樹脂からなる。
また、マイクロ波吸収発熱体用フェライト粉は、電磁波を吸収して発熱するＭｎＺｎ系フェライト粉と電磁波を吸収して発熱するＮｉ系フェライト粉との混合粉からなる。
Hereinafter, the present invention will be specifically described.
The microwave absorption heating element of the present invention comprises a ferrite powder for a microwave absorption heating element and a resin.
Further, the ferrite powder for microwave absorption heating element is composed of a mixed powder of MnZn-based ferrite powder that absorbs electromagnetic waves to generate heat and Ni-based ferrite powder that absorbs electromagnetic waves to generate heat.
マイクロ波吸収発熱体用フェライト粉（ＭｎＺｎ系フェライト粉：Ｎｉ系フェライト粉＝３０〜７０：３０〜７０（ｍａｓｓ％））
マイクロ波吸収発熱体用フェライト粉におけるＮｉ系フェライトの混合比が３０（ｍａｓｓ％）未満の場合、ＭｎＺｎ系フェライトの昇温特性とほとんど変わらない特性しか得られない。一方、マイクロ波吸収発熱体用フェライト粉におけるＮｉ系フェライトの混合比が７０（ｍａｓｓ％）を超えると、Ｎｉ系フェライトの昇温特性とほとんど変わらない特性しか得られない。
そのため、ＭｎＺｎ系フェライト粉：Ｎｉ系フェライト粉は、３０〜７０：３０〜７０（ｍａｓｓ％）の範囲で混合する。
Ferrite powder for microwave absorption heating element (MnZn ferrite powder: Ni ferrite powder = 30 to 70 : 30 to 70 (mass%))
When the mixing ratio of the Ni-based ferrite in the ferrite powder for microwave absorption heating elements is less than 30 (mass%), only the temperature rising characteristics of the MnZn-based ferrite are almost the same. On the other hand, when the mixing ratio of the Ni-based ferrite in the ferrite powder for microwave absorption heating element exceeds 70 (mass%), only the characteristics that are almost the same as the temperature rising characteristics of the Ni-based ferrite are obtained.
Therefore, the MnZn-based ferrite powder and the Ni-based ferrite powder are mixed in the range of 30 to 70 : 30 to 70 (mass%) .
図１に、ＭｎＺｎ系フェライトに対するＮｉ系フェライトの置換量と、マイクロ波照射２０秒後の試料温度との関係について調べた結果を示す。
図１に示したように、ＭｎＺｎ系フェライト粉とＮｉ系フェライト粉との混合比を上記の範囲に調整することで、単純な混合比からの比例計算から予想される温度（図１中の点線で示した線）よりも短時間で高温となる。すなわち、マイクロ波吸収発熱体の立上りの昇温速度を速くすることができる。
FIG. 1 shows the result of examination on the relationship between the substitution amount of Ni-based ferrite for MnZn-based ferrite and the
As shown in FIG. 1, by adjusting the mixing ratio of the MnZn-based ferrite powder and the Ni-based ferrite powder within the above range, the temperature expected from the proportional calculation from the simple mixing ratio (dotted line in FIG. 1) The temperature becomes higher in a shorter time than the line indicated by. That is, the rising temperature rising rate of the microwave absorption heating element can be increased.
上記立上りの昇温速度が速くなる理由は今のところ不明であるが、発明者らは、飽和磁化や透磁率、誘電率などの物性の異なる粒子が共存することで、マイクロ波をより吸収しやすい状態になっているのではないかと考えている。 The reason why the rate of temperature rise at the rise becomes faster is not clear at present, but the inventors have further absorbed microwaves by coexistence of particles having different physical properties such as saturation magnetization, magnetic permeability, and dielectric constant. I think it is in an easy state.
上記したマイクロ波吸収発熱体用フェライトは、粉末状なので、樹脂との混合による成形品である発熱体に用いるのに適している。
ここで、上記樹脂の種類は、用途および昇温停止温度によって適宜選択されるが、例えば、２５０℃を超える高温を選択するのであれば、シリコーン樹脂やＰＰＳ（ポリフェニレンサルファイド）などの耐熱樹脂を用いることが好ましい。
また、マイクロ波吸収発熱体用フェライト粉と樹脂との混合比は、発熱性能および成形品の品質に影響するため、製品の発熱性能および成形品の品質から適宜決めることができる。
Since the above-mentioned ferrite for microwave absorption heating element is in the form of powder, it is suitable for use as a heating element which is a molded product by mixing with a resin.
Here, the type of the above resin is appropriately selected depending on the application and the temperature at which the temperature is raised and stopped. For example, if a high temperature exceeding 250 ° C. is selected, a heat resistant resin such as silicone resin or PPS (polyphenylene sulfide) is used. Preferably.
Further, the mixing ratio of the ferrite powder for microwave absorption heating element and the resin affects the heat generation performance and the quality of the molded product, and can be appropriately determined from the heat generation performance of the product and the quality of the molded product.
しかしながら、樹脂の混合比が７０ｍａｓｓ％を超えると、マイクロ波吸収発熱体用フェライト粉の含有量が少ないために、昇温速度が遅くなり、昇温停止温度も低下する。一方、樹脂量が１０ｍａｓｓ％未満では、粉体同志の結着力が弱いために、実用的な機械的強度の成形品を得ることができない。従って、本発明では、マイクロ波吸収発熱体用フェライト粉：樹脂＝３０〜９０：１０〜７０（ｍａｓｓ％）に限定する。好ましくは、マイクロ波吸収発熱体用フェライト粉：樹脂＝６０〜８５：１５〜４０（ｍａｓｓ％）の範囲である。 However, when the mixing ratio of the resin exceeds 70 mass%, the rate of temperature increase becomes slower and the temperature increase stop temperature also decreases because the content of the ferrite powder for microwave absorption heating element is small. On the other hand, when the amount of resin is less than 10 mass%, the binding force between the powders is weak, so that a molded product having practical mechanical strength cannot be obtained. Therefore, in the present invention, it is limited to ferrite powder for microwave absorption heating element: resin = 30 to 90:10 to 70 (mass%). Preferably, the range is ferrite powder for microwave absorption heating element: resin = 60 to 85:15 to 40 (mass%).
本発明のＭｎＺｎ系フェライト粉は、一般に電源トランスやノイズフィルタ用に市販されているＭｎＺｎフェライトコアを粉砕した物を使用できるが、飽和磁束密度の高い組成のものを用いると、より高い発熱性能が得られるので好適である。 As the MnZn-based ferrite powder of the present invention, it is possible to use a pulverized MnZn ferrite core which is generally commercially available for a power transformer and a noise filter. However, when a composition having a high saturation magnetic flux density is used, higher heat generation performance is obtained. It is preferable because it can be obtained.
具体的には、Ｆｅ酸化物（Ｆｅ2Ｏ3換算）：５３〜５７ｍｏｌ％、Ｚｎ酸化物（ＺｎＯ換算）：４〜１１ｍｏｌ％およびＮｉ酸化物（ＮｉＯ換算）：０〜４ｍｏｌ％を含み、残部がＭｎ酸化物からなるＭｎＺｎ系フェライト粉であることが高飽和磁束密度の点から好ましい。 Specifically, the Fe oxide (Fe 2 O 3 equivalent): 53 to 57 mol%, the Zn oxide (ZnO equivalent): 4 to 11 mol% and the Ni oxide (NiO equivalent): 0 to 4 mol%, and the balance Is preferably a MnZn-based ferrite powder composed of Mn oxide from the viewpoint of high saturation magnetic flux density.
Ｆｅ酸化物（Ｆｅ2Ｏ3換算）：５３〜５７ｍｏｌ％
Ｆｅ2Ｏ3が多過ぎるとＭｎＺｎフェライトの焼成段階で異相が析出しやすくなり、発熱性能に悪影響を及ぼす。従って、Ｆｅ酸化物はＦｅ2Ｏ3換算で５７ｍｏｌ％以下が好ましく、５６ｍｏｌ％以下がより好ましい。一方、Ｆｅ2Ｏ3が少なくなるとキュリー温度が低下し、昇温停止温度が低温化する。従って、昇温停止温度を２００℃以上に調整するためには、Ｆｅ酸化物はＦｅ2Ｏ3換算で５３ｍｏｌ％以上が好ましく、５４ｍｏｌ％以上がより好ましい。
Fe oxide (Fe 2 O 3 conversion): 53 to 57 mol%
If the amount of Fe 2 O 3 is too large, a different phase is likely to precipitate during the firing of MnZn ferrite, which adversely affects the heat generation performance. Therefore, the Fe oxide is preferably 57 mol% or less, and more preferably 56 mol% or less in terms of Fe 2 O 3 . On the other hand, when the Fe 2 O 3 content decreases, the Curie temperature decreases, and the temperature rise stop temperature decreases. Therefore, in order to adjust the temperature increase stop temperature to 200 ° C. or higher, the Fe oxide is preferably 53 mol% or more, more preferably 54 mol% or more in terms of Fe 2 O 3 .
Ｚｎ酸化物（ＺｎＯ換算）：４〜１１ｍｏｌ％
ＺｎＯは飽和磁束密度の温度依存性に関係する。ＺｎＯが１１ｍｏｌ％を超えるとキュリー温度が低下し、昇温停止温度が２００℃以下に低下する。従って、Ｚｎ酸化物はＺｎＯ換算で１１ｍｏｌ％以下が好ましく、１０ｍｏｌ％以下がより好ましい。一方、ＺｎＯが４ｍｏｌ％未満では飽和磁束密度が低下して発熱性能に悪影響を及ぼす。従って、Ｚｎ酸化物はＺｎＯ換算で４ｍｏｌ％以上が好ましく、５ｍｏｌ％以上がより好ましい。
Zn oxide (ZnO equivalent): 4 to 11 mol%
ZnO is related to the temperature dependence of the saturation magnetic flux density. If ZnO exceeds 11 mol%, the Curie temperature is lowered and the temperature rise stop temperature is lowered to 200 ° C. or lower. Therefore, the Zn oxide is preferably 11 mol% or less in terms of ZnO, and more preferably 10 mol% or less. On the other hand, when ZnO is less than 4 mol%, the saturation magnetic flux density is lowered and the heat generation performance is adversely affected. Therefore, the Zn oxide is preferably 4 mol% or more in terms of ZnO, and more preferably 5 mol% or more.
Ｎｉ酸化物（ＮｉＯ換算）：０〜４ｍｏｌ％
ＮｉＯは複素透磁率の虚数成分μ’’の温度特性に関係する。２．４５ＧＨｚのμ’’が大きいほど高周波磁気損失に起因するマイクロ波発熱能が高くなる。ＮｉＯを含まないとμ’’の値は室温で大きく、ＮｉＯ量とともにμ’’のピーク温度は高温化する。ＮｉＯが４ｍｏｌ％を超えると、μ’’の値は高温では高いものの、室温付近では小さくなり。発熱体の温度の立ち上がりが遅くなる。従って、Ｎｉ酸化物はＮｉＯ換算で４ｍｏｌ％以下が好ましく、３ｍｏｌ％以上がより好ましい。一方、ＮｉＯの含有量が少ないと、室温付近のμ’’は高いものの、高温で低μ’’となり、昇温の立上りは速いが、その後昇温が遅くなってしまう。しかし、本発明ではＮｉＺｎ系フェライトと混合することでその影響は小さい。従って、Ｎｉ酸化物は含まなくても良い。
Ni oxide (NiO conversion): 0 to 4 mol%
NiO is related to the temperature characteristic of the imaginary component μ ″ of the complex magnetic permeability. The larger the μ ″ of 2.45 GHz, the higher the microwave heating ability due to the high frequency magnetic loss. When NiO is not included, the value of μ ″ is large at room temperature, and the peak temperature of μ ″ increases with the amount of NiO. When the NiO content exceeds 4 mol%, the value of μ ″ is high at high temperatures, but it becomes small near room temperature. The temperature of the heating element rises slowly. Therefore, the Ni oxide is preferably 4 mol% or less in terms of NiO, and more preferably 3 mol% or more. On the other hand, when the content of NiO is small, μ ″ near room temperature is high, but it becomes low μ ″ at high temperature, and the rise of temperature rise is fast, but thereafter the temperature rise becomes slow. However, in the present invention, the effect is small by mixing with NiZn ferrite. Therefore, the Ni oxide may not be included.
また、本発明のＮｉ系フェライト粉は、ＣｕＯを３〜１４ｍｏｌ％含有する組成のものが、明瞭な昇温停止挙動が得られるので好適である。
さらに具体的には、Ｆｅ酸化物（Ｆｅ2Ｏ3換算）：４６〜５１ｍｏｌ％、Ｃｕ酸化物（ＣｕＯ換算）：３〜１４ｍｏｌ％、Ｚｎ酸化物（ＺｎＯ換算）：０〜３８ｍｏｌ％を含み、残部がＮｉ酸化物からなるＮｉ系フェライト粉であることが昇温停止挙動の安定性の点から好ましい。
Further, the Ni-based ferrite powder of the present invention preferably has a composition containing CuO in an amount of 3 to 14 mol% because a clear temperature rising stop behavior can be obtained.
More specifically, it contains Fe oxide (Fe 2 O 3 conversion): 46 to 51 mol%, Cu oxide (CuO conversion): 3 to 14 mol%, Zn oxide (ZnO conversion): 0 to 38 mol%, It is preferable that the balance is Ni-based ferrite powder made of Ni oxide from the viewpoint of the stability of the temperature rise stopping behavior.
Ｆｅ酸化物（Ｆｅ2Ｏ3換算）：４６〜５１ｍｏｌ％
Ｆｅ2Ｏ3は、フェライト相の安定性および比抵抗に影響を与え、マイクロ波印加による昇温速度に作用する。Ｆｅ2Ｏ3換算で５１ｍｏｌ％を超えると、発熱体の比抵抗が低下して金属のようにマイクロ波を反射して発熱性能が低下する。従って、Ｆｅ酸化物はＦｅ2Ｏ3換算で５１ｍｏｌ％以下が好ましく、５０ｍｏｌ％以下がより好ましい。一方、Ｆｅ2Ｏ3が少ないとフェライト以外の相が生成してフェライト単相を得ることが難しくなり、発熱体の昇温速度が低下する。従って、Ｆｅ酸化物濃度はＦｅ2Ｏ3換算で４６ｍｏｌ％以上が好ましく、４７ｍｏｌ％以上がより好ましい。
Fe oxide (converted to Fe 2 O 3 ): 46 to 51 mol%
Fe 2 O 3 affects the stability and specific resistance of the ferrite phase, and acts on the rate of temperature rise due to microwave application. If it exceeds 51 mol% in terms of Fe 2 O 3 , the specific resistance of the heating element is lowered and microwaves are reflected like metal so that the heating performance is lowered. Therefore, the Fe oxide is preferably 51 mol% or less in terms of Fe 2 O 3 , and more preferably 50 mol% or less. On the other hand, when the amount of Fe 2 O 3 is small, a phase other than ferrite is generated and it is difficult to obtain a ferrite single phase, and the heating rate of the heating element is reduced. Therefore, the Fe oxide concentration is preferably 46 mol% or more, and more preferably 47 mol% or more in terms of Fe 2 O 3 .
Ｃｕ酸化物（ＣｕＯ換算）：３〜１４ｍｏｌ％
ＣｕＯは、マイクロ波印加による昇温特性において、高温での昇温停止挙動に影響する。ＣｕＯが３ｍｏｌ％に満たないか、または１４ｍｏｌ％を超えたときは、いずれの場合も発熱体の昇温が停止せずに、マイクロ波照射と共に発熱体の温度が上昇し続けてしまう。従って、Ｃｕ酸化物はＣｕＯ換算で３〜１４ｍｏｌ％の範囲が好ましく、４〜１０ｍｏｌ％がより好ましい。
Cu oxide (CuO equivalent): 3 to 14 mol%
CuO influences the temperature rising stop behavior at a high temperature in the temperature rising characteristics due to microwave application. When CuO is less than 3 mol% or exceeds 14 mol%, the temperature of the heating element does not stop in any case and the temperature of the heating element continues to rise with microwave irradiation. Therefore, the Cu oxide content is preferably 3 to 14 mol% in terms of CuO, and more preferably 4 to 10 mol%.
Ｚｎ酸化物（ＺｎＯ換算）：０〜３８ｍｏｌ％
ＺｎＯは、マイクロ波印加による昇温特性において、昇温停止温度に影響する。ＺｎＯ換算で０〜３８ｍｏｌ％に調整することで、５０〜５５０℃の広い温度範囲にわたって昇温停止温度を設定することができる。ＺｎＯが０ｍｏｌ％の場合、５５０℃程度まで昇温する。ＺｎＯが３８ｍｏｌ％超の場合、５０℃以上に昇温しない。従って、Ｚｎ酸化物はＺｎＯ換算で０〜３８ｍｏｌ％以上が好ましく、２〜３５ｍｏｌ％がより好ましく、３〜２０ｍｏｌ％がさらに好ましい。
Zn oxide (ZnO equivalent): 0 to 38 mol%
ZnO affects the temperature rising stop temperature in the temperature rising characteristics by applying microwaves. By adjusting to 0 to 38 mol% in terms of ZnO, the temperature rise stop temperature can be set over a wide temperature range of 50 to 550 ° C. When ZnO is 0 mol%, the temperature is raised to about 550 ° C. When ZnO exceeds 38 mol%, the temperature does not rise to 50 ° C. or higher. Therefore, the Zn oxide is preferably 0 to 38 mol% or more, more preferably 2 to 35 mol%, and further preferably 3 to 20 mol% in terms of ZnO.
なお、本発明における昇温停止温度Ｔｓとは、発熱フェライト粉と耐熱樹脂を混練してシート成形し、４０×４０ｍｍに切断加工して得たフェライト粉含有樹脂シートを、市販の電子レンジを用いて、５００Ｗのマイクロ波を照射した後の試料表面温度がほとんど温度変化なく一定と見なされた時の温度とする。また、試料表面温度は、赤外線放射温度計で測定する。 In addition, the temperature rising stop temperature Ts in the present invention means that a ferrite powder-containing resin sheet obtained by kneading exothermic ferrite powder and heat-resistant resin to form a sheet and cutting into 40 × 40 mm is used in a commercially available microwave oven. The temperature at which the surface temperature of the sample after being irradiated with the microwave of 500 W is considered to be constant with almost no temperature change. The sample surface temperature is measured with an infrared radiation thermometer.
上述したとおり、本発明によれば、特定組成のＭｎＺｎ系フェライト粉と特定組成のＮｉ系フェライト粉の混合比を（ＭｎＺｎ系フェライト粉：Ｎｉ系フェライト粉＝３０〜９０：１０〜７０（ｍａｓｓ％））の範囲内で適宜調整することにより、昇温停止温度や昇温速度が異なる種々のマイクロ波吸収発熱体用フェライト粉を簡便に作り分けることができる。 As described above, according to the present invention, the mixing ratio of the MnZn-based ferrite powder of the specific composition and the Ni-based ferrite powder of the specific composition is (MnZn-based ferrite powder: Ni-based ferrite powder = 30 to 90:10 to 70 (mass%). By appropriately adjusting the temperature within the range of)), various ferrite powders for microwave absorption heating elements having different heating stop temperatures and heating rates can be easily prepared.
以下、本発明の具体的実施例について説明する。
（実施例１）
ＭｎＺｎ系フェライト粉は、Ｆｅ2Ｏ3：ＭｎＯ：ＮｉＯ：ＺｎＯ＝５５．０：３５．０：２．５：７．５（ｍｏｌ％）の基本組成として原料を混合し、ついで、１３００℃で焼成、解砕、分級して得た。
Ｎｉ系フェライト粉は、Ｆｅ2Ｏ3：ＮｉＯ：ＺｎＯ：ＣｕＯ＝４９：３２：１３：６ｍｏｌ％の基本組成として原料を混合し、ついで、１１００℃で焼成、解砕、分級して得た。
表１に示す比率でＭｎＺｎ系フェライト粉とＮｉ系フェライト粉を混合し、次いで、マイクロ波吸収発熱体用フェライト粉：シリコーン樹脂＝７５：２５の質量比で混練し、４０×４０×１ｍｍのシートを作製した。得られたシートを市販の電子レンジの中に置き、５００Ｗのマイクロ波を１０秒〜９０秒間照射した時のシートの温度を赤外線放射温度計で測定した。
Hereinafter, specific examples of the present invention will be described.
(Example 1)
The MnZn-based ferrite powder is prepared by mixing the raw materials as a basic composition of Fe 2 O 3 : MnO: NiO: ZnO = 55.0: 35.0: 2.5: 7.5 (mol%), and then at 1300 ° C. It was obtained by firing, crushing and classification.
The Ni-based ferrite powder was obtained by mixing the raw materials as a basic composition of Fe 2 O 3 : NiO: ZnO: CuO = 49: 32: 13: 6 mol%, followed by firing at 1100 ° C., crushing and classification.
A MnZn-based ferrite powder and a Ni-based ferrite powder were mixed in the ratios shown in Table 1, and then kneaded in a mass ratio of ferrite powder for microwave absorption heating element: silicone resin = 75: 25 to obtain a sheet of 40 × 40 × 1 mm. Was produced. The obtained sheet was placed in a commercially available microwave oven and the temperature of the sheet when irradiated with a microwave of 500 W for 10 seconds to 90 seconds was measured by an infrared radiation thermometer.
上記した本発明に従う発明例および比較例のマイクロ波吸収発熱体用フェライト粉を用いた場合の樹脂シートの表面温度測定結果を表１および図２に示す。 Table 1 and FIG. 2 show the results of measuring the surface temperature of the resin sheet when the ferrite powders for microwave absorption heating elements of the inventive examples and comparative examples according to the present invention described above were used.
表１および図２、また、前掲した図１に示したとおり、２種のマイクロ波吸収発熱体用フェライト粉から、昇温の立ち上がりが早く、所望の昇温停止温度の樹脂シートを作製できることが判る。 As shown in Table 1 and FIG. 2, and also in FIG. 1 described above, it is possible to produce a resin sheet having a desired temperature rising stop temperature from two types of ferrite powder for microwave absorption heating elements with a rapid rise in temperature rising. I understand.
（実施例２）
ＭｎＺｎ系フェライト粉は実施例１と同様な方法で作製した。
Ｎｉ系フェライト粉は、Ｆｅ2Ｏ3：ＮｉＯ：ＺｎＯ：ＣｕＯ＝４８：４０：５：７ｍｏｌ％の基本組成として原料を混合し、ついで、１０００℃で焼成、解砕、分級して得た。
上記のＭｎＺｎ系フェライト粉とＮｉ系フェライト粉を６５：３５ｍａｓｓ％の比率で混合し、次いで、マイクロ波吸収発熱体用フェライト粉：シリコーン樹脂＝７５：２５の質量比で混練し、４０×４０×１ｍｍのシートを作製した。得られたシートを市販の電子レンジの中に置き、５００Ｗのマイクロ波を１０秒〜９０秒間照射した時のシートの温度を赤外線放射温度計で測定した（発明例８）。
比較例として、Ｎｉ系フェライト粉をＦｅ2Ｏ3：ＮｉＯ：ＺｎＯ：ＣｕＯ＝４８：２８：１７：７ｍｏｌ％の基本組成として原料を混合し、ついで、１０００℃で焼成、解砕、分級して得た。Ｎｉ系フェライト粉単体：シリコーン樹脂＝７５：２５の質量比で混練し、発明例８と同様の方法で樹脂シートを作製して、マイクロ波昇温特性を測定した（比較例５）。比較例５のフェライト粉はＮｉ系フェライト粉のみであり、ＭｎＺｎ系フェライト粉を含んでいない。
本発明に従う発明例８および比較例５のマイクロ波昇温特性を図３に示す。
(Example 2)
The MnZn ferrite powder was produced by the same method as in Example 1.
The Ni-based ferrite powder was obtained by mixing the raw materials as a basic composition of Fe 2 O 3 : NiO: ZnO: CuO = 48: 40: 5: 7 mol%, followed by firing at 1000 ° C., crushing and classification.
The above MnZn-based ferrite powder and Ni-based ferrite powder were mixed at a ratio of 65:35 mass%, and then kneaded at a mass ratio of ferrite powder for microwave absorption heating element: silicone resin = 75: 25, and 40 × 40 × A 1 mm sheet was made. The obtained sheet was placed in a commercially available microwave oven, and the temperature of the sheet when irradiated with a microwave of 500 W for 10 seconds to 90 seconds was measured with an infrared radiation thermometer (Invention Example 8).
As a comparative example, the Ni-based ferrite powder was mixed with the raw materials as a basic composition of Fe 2 O 3 : NiO: ZnO: CuO = 48: 28: 17: 7 mol%, and then calcined at 1000 ° C., crushed, and classified. Obtained. Ni-based ferrite powder alone: Silicone resin was kneaded at a mass ratio of 75:25, a resin sheet was prepared in the same manner as in Inventive Example 8, and microwave heating characteristics were measured (Comparative Example 5). The ferrite powder of Comparative Example 5 was only Ni-based ferrite powder and did not contain MnZn-based ferrite powder.
The microwave temperature rising characteristics of Inventive Example 8 and Comparative Example 5 according to the present invention are shown in FIG.
図３に示したとおり、発明例８および比較例５は約３２０℃で昇温停止するが、昇温の立ち上がりを比較すると、２種のマイクロ波吸収発熱体用フェライト粉からなる本発明例の方が早いことが判る。 As shown in FIG. 3, in Invention Example 8 and Comparative Example 5, the temperature rise is stopped at about 320 ° C., but when the rising of the temperature rise is compared, the invention example of two kinds of ferrite powder for microwave absorption heating element is compared. It turns out that it is faster.
（実施例３）
ＭｎＺｎ系フェライト粉は、Ｆｅ2Ｏ3：ＭｎＯ：ＺｎＯ＝５５：４０：５ｍｏｌ％の基本組成として原料を混合し、ついで、１３２０℃で焼成、解砕、分級して得た。
Ｎｉ系フェライト粉は、Ｆｅ2Ｏ3：ＮｉＯ：ＺｎＯ：ＣｕＯ＝４９：３１．５：１４．５：５ｍｏｌ％の基本組成として原料を混合し、ついで、９５０℃で焼成、解砕、分級して得た。
上記のＭｎＺｎ系フェライト粉とＮｉ系フェライト粉を５０：５０ｍａｓｓ％の比率で混合し、次いで、マイクロ波吸収発熱体用フェライト粉：シリコーン樹脂＝７５：２５の質量比で混練し、４０×４０×１ｍｍのシートを作製した。得られたシートを市販の電子レンジの中に置き、５００Ｗのマイクロ波を１０秒〜９０秒間照射した時のシートの温度を赤外線放射温度計で測定した（発明例９）。
比較例として、上記のＭｎＺｎ系フェライト粉単体：シリコーン樹脂＝７５：２５の質量比で混練した（比較例６）。比較例６のフェライト粉はＭｎＺｎ系フェライト粉のみであり、Ｎｉ系フェライト粉を含んでいない。
また、上記のＮｉ系フェライト粉単体：シリコーン樹脂＝７５：２５の質量比で混練して、同様の方法で樹脂シートを作製して、マイクロ波昇温特性を測定した（比較例７）。比較例７のフェライト粉はＮｉ系フェライト粉のみであり、ＭｎＺｎ系フェライト粉を含んでいない。
本発明に従う発明例９および比較例６、比較例７のマイクロ波昇温特性を図４に示す。
(Example 3)
The MnZn-based ferrite powder was obtained by mixing the raw materials as a basic composition of Fe 2 O 3 : MnO: ZnO = 55: 40: 5 mol%, and then calcining at 1320 ° C., crushing and classification.
The Ni-based ferrite powder is prepared by mixing the raw materials as a basic composition of Fe 2 O 3 : NiO: ZnO: CuO = 49: 31.5: 14.5: 5 mol%, and then firing, crushing and classifying at 950 ° C. I got it.
The above MnZn-based ferrite powder and Ni-based ferrite powder were mixed in a ratio of 50:50 mass%, and then kneaded in a mass ratio of ferrite powder for microwave absorption heating element: silicone resin = 75: 25, and 40 × 40 × A 1 mm sheet was made. The obtained sheet was placed in a commercially available microwave oven, and the temperature of the sheet when irradiated with a microwave of 500 W for 10 seconds to 90 seconds was measured with an infrared radiation thermometer (Invention Example 9).
As a comparative example, the above MnZn-based ferrite powder alone: silicone resin = 75: 25 were mixed in a mass ratio (Comparative Example 6). The ferrite powder of Comparative Example 6 was only MnZn-based ferrite powder and did not contain Ni-based ferrite powder.
Further, the above Ni-based ferrite powder alone: silicone resin = 75: 25 was mixed and kneaded at a mass ratio to prepare a resin sheet by the same method, and microwave heating characteristics were measured (Comparative Example 7). The ferrite powder of Comparative Example 7 was only Ni-based ferrite powder, and did not contain MnZn-based ferrite powder.
FIG. 4 shows the microwave temperature rising characteristics of Inventive Example 9 and Comparative Examples 6 and 7 according to the present invention.
図４に示したとおり、２種のマイクロ波吸収発熱体用フェライト粉からなる本発明例の方が昇温の立ち上がりが早いことが判る。 As shown in FIG. 4, it can be seen that the rise of the temperature rise is faster in the example of the present invention composed of the two types of ferrite powder for microwave absorption heating element.
以上のように、本発明を用いることで、簡便な方法で、昇温の立ち上がりが早く、所期した温度で昇温停止できるマイクロ波吸収発熱体用フェライト粉を作り分けることができる。このため、電子レンジ用発熱調理器や、マイクロ波を利用した保温材、温熱医療用発熱体など、産業用加熱用途に対して好適に利用できる。 As described above, by using the present invention, it is possible to easily produce ferrite powders for microwave absorption heating elements that can quickly rise in temperature and can be stopped at a desired temperature by a simple method. For this reason, it can be suitably used for industrial heating applications such as a heating cooker for a microwave oven, a heat insulating material using microwaves, and a heating element for hot medical treatment.
Claims (1)
前記ＭｎＺｎ系フェライト粉は、Ｆｅ酸化物（Ｆｅ 2 Ｏ 3 換算）：５３〜５７ｍｏｌ％、Ｚｎ酸化物（ＺｎＯ換算）：４〜１１ｍｏｌ％およびＮｉ酸化物（ＮｉＯ換算）：０〜４ｍｏｌ％を含み、残部がＭｎ酸化物からなり、
前記Ｎｉ系フェライト粉は、Ｆｅ酸化物（Ｆｅ 2 Ｏ 3 換算）：４６〜５１ｍｏｌ％、Ｃｕ酸化物（ＣｕＯ換算）：３〜１４ｍｏｌ％、Ｚｎ酸化物（ＺｎＯ換算）：０〜３８ｍｏｌ％を含み、残部がＮｉ酸化物からなることを特徴とするマイクロ波吸収発熱体。 The MnZn-based ferrite powder that absorbs electromagnetic waves and generates heat and the Ni-based ferrite powder that absorbs electromagnetic waves and generates heat are mixed in the range of MnZn-based ferrite powder: Ni-based ferrite powder = 30 to 70 : 30 to 70 (mass%). The mixed ferrite powder for microwave absorption heating element is contained in the resin at a ratio of 30 to 90 (mass%) ,
The MnZn-based ferrite powder contains Fe oxide (Fe 2 O 3 conversion): 53 to 57 mol%, Zn oxide (ZnO conversion): 4 to 11 mol%, and Ni oxide (NiO conversion): 0 to 4 mol%. , The balance consists of Mn oxide,
The Ni-based ferrite powder contains Fe oxide (Fe 2 O 3 conversion): 46 to 51 mol%, Cu oxide (CuO conversion): 3 to 14 mol%, Zn oxide (ZnO conversion): 0 to 38 mol%. A microwave absorbing heating element , the balance of which is made of Ni oxide .
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| JP5559572B2 (en) * | 2010-03-08 | 2014-07-23 | タイガースポリマー株式会社 | Clay-like modeling material and its crosslinking method |
| JP5017438B2 (en) * | 2010-09-06 | 2012-09-05 | Ｊｆｅケミカル株式会社 | Cooking device for electromagnetic wave absorption heating element and microwave oven |
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