JP4572474B2 - Electrical steel sheet with insulating coating with excellent adhesion - Google Patents
Electrical steel sheet with insulating coating with excellent adhesion Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、回転器、変圧器等に用いられる積層鉄芯の材料として用いられる、加熱接着型の絶縁被膜付き電磁鋼板に関する。また、本発明は、積層電磁鋼板および積層鉄芯ならびにこれらの製造方法に関する。
【０００２】
【従来の技術】
従来、回転器、変圧器等の電気機器に使用される鉄芯は、まず電磁鋼板に渦電流を減少させるための絶縁被膜を施し、それを打ち抜き、またはせん断加工し、多数積み重ね、更に、溶接、カシメまたは接着剤により固着させることにより製造されていた。
しかしながら、溶接により固着させる方法には、鉄芯エッジ部が短絡され絶縁性が低下するという問題や、熱歪みにより磁気特性が劣化するという問題があった。また、カシメにより固着させる方法には、加工歪みにより磁気特性が劣化するという問題があった。また、接着剤により固着させる方法には、上述したような磁気特性の劣化の問題はあまりないが、電磁鋼板１枚毎に接着剤を塗布する必要があるため作業性が悪いという問題や、絶縁被膜間での接着力が十分でないという問題があった。
【０００３】
これに対し、特開平２−２０８０３４号公報には、ガラス転移温度６０℃以上の熱可塑性アクリル樹脂エマルジョン、エポキシ樹脂エマルジョン等を主成分とする組成物を塗布し乾燥して得られた鋼板を積層し、加熱加圧して積層鉄芯を製造する方法が記載されている。この方法は、接着剤を塗布する工程を省略したものであり、加工歪みの影響を受けにくく、コイル状に巻いた場合においてもブロッキングしにくいという利点を有する。
しかしながら、上記方法で製造された電磁鋼板（以下「従来の加熱接着型電磁鋼板」という。）を加熱加圧して得られた実際の積層鉄芯においては、接着が不完全な部分が存在する場合があり、ひどい時には接着不良による層間はく離（接着面でのはく離）を引き起こすという問題があった。特に、鉄芯が大きい場合には、被膜や鋼板の凹凸の影響を受けやすく、問題が顕在化しやすかった。
【０００４】
図を用いて説明する。図１は、従来の加熱接着型電磁鋼板を積層し、加熱加圧して得られる積層鉄芯１における、接着性樹脂を含有する絶縁被膜２の模式的な断面図である。接着前において、絶縁被膜２の表面は外観上全く平坦に見えていても、塗布時の塗布ロールのローピング等による微妙な畝状の被膜の凹凸が存在しており、加熱加圧を行ってもその凹部が接着しない場合がある。その結果、接着良好部分３と非接着部分４とが縞状に存在し、完全接着に至らないことが生じうる。これが、積層鉄芯１の積層コアの内外を密封したい場合においては、漏れの原因となる。また、板厚偏差、膜厚偏差等の理由により加圧不足となった部分においては、絶縁被膜２同士が十分に貼り付かずに、コア割れを起こす場合がある。コア割れ部分５は、層間はく離を起こしている部分である。実際の製品には、板厚偏差、膜厚偏差、絶縁被膜の凹凸等がどうしても存在し、一方、加熱加圧時の圧力も装置の都合上大きくすることができないことも多いため、上記問題が生じる可能性は多かれ少なかれ残ってしまう。
【０００５】
【発明が解決しようとする課題】
したがって、本発明は、表面に接着性樹脂を含有する絶縁被膜を有する電磁鋼板であって、積層し加熱加圧した場合に、該絶縁被膜同士が十分に接着しうる電磁鋼板を提供することを目的とする。
また、本発明は、電磁鋼板を２枚以上積層してなる積層電磁鋼板であって、各電磁鋼板の間の接着性樹脂を含有する接着層により電磁鋼板同士が十分に接着している積層電磁鋼板、およびその製造方法を提供することを目的とする。
更に、本発明は、電磁鋼板を２枚以上積層してなる積層鉄芯であって、各電磁鋼板の間の接着性樹脂を含有する接着層により電磁鋼板同士が十分に接着している積層鉄芯、およびその製造方法を提供することを目的とする。
【０００６】
【課題を解決するための手段】
本発明者は、上記課題を解決すべく鋭意研究した結果、絶縁被膜を構成する接着性樹脂に特定量の発泡剤を含有させておくと、加熱加圧時に発泡剤が発泡し、絶縁被膜が膨張して非接着部分が生じないことを見出し、本発明を完成した。
【０００７】
即ち、本発明は、電磁鋼板の少なくとも一方の表面に絶縁被膜を設けてなる絶縁被膜付き電磁鋼板であって、該絶縁被膜が接着性樹脂および発泡剤を含有し、該発泡剤の含有量が該接着性樹脂１００質量部に対して０．０１〜２質量部である絶縁被膜付き電磁鋼板を提供する。
図２は、上述した（ａ）従来の加熱接着型電磁鋼板を積層してなる積層電磁鋼板と、（ｂ）本発明の絶縁被膜付き電磁鋼板を積層してなる積層電磁鋼板の加熱加圧前後の状態を示す断面模式図である。なお、本発明の絶縁被膜付き電磁鋼板はこれに限定されない。
電磁鋼板１１に接着性樹脂被膜（接着性樹脂を含有する絶縁被膜）１２を設けてなる従来の加熱接着型電磁鋼板１０は、積層して加熱加圧すると、接着性樹脂被膜１２の凹凸に起因して、接着良好部分１３と非接着部分１４とが生じてしまう。これに対して、電磁鋼板２１に接着性樹脂および発泡剤を含有する絶縁被膜２２を設けてなる本発明の絶縁被膜付き電磁鋼板２０は、積層して加熱加圧すると、加熱により発泡剤の一部または全部が発泡して気泡２３が生じ、これにより絶縁被膜２２が膨張して、絶縁被膜２２同士の間に隙間を生じさせることなく、接着するのである。したがって、本発明の絶縁被膜付き電磁鋼板によれば、積層し加熱加圧した場合に、絶縁被膜同士が十分に密接に接着しうる。
【０００８】
また、本発明は、絶縁被膜付き電磁鋼板を前記絶縁被膜同士が接着するように２枚以上積層した後、前記発泡剤の分解開始温度以上の温度になるように加熱加圧して、前記発泡剤の一部または全部を発泡させることにより得られた積層電磁鋼板を提供する。
【０００９】
また、本発明は、絶縁被膜付き電磁鋼板を前記絶縁被膜同士が接着するように２枚以上積層した後、前記発泡剤の分解開始温度以上の温度になるように加熱加圧して、前記発泡剤の一部または全部を発泡させることにより得られた積層鉄芯を提供する。
【００１０】
また、本発明は、前記絶縁被膜付き電磁鋼板を前記絶縁被膜同士が接着するように２枚以上積層した後、前記発泡剤の分解開始温度以上の温度になるように加熱加圧して、前記発泡剤の一部または全部を発泡させることにより積層電磁鋼板を得ることを特徴とする積層電磁鋼板の製造方法を提供する。
【００１１】
また、本発明は、前記絶縁被膜付き電磁鋼板を前記絶縁被膜同士が接着するように２枚以上積層した後、前記発泡剤の分解開始温度以上の温度になるように加熱加圧して、前記発泡剤の一部または全部を発泡させることにより積層鉄芯を得ることを特徴とする積層鉄芯の製造方法を提供する。
【００１２】
【発明の実施の形態】
以下、本発明について詳細に説明する。
初めに、本発明の絶縁被膜付き電磁鋼板について説明する。本発明の絶縁被膜付き電磁鋼板は、電磁鋼板の少なくとも一方の表面に絶縁被膜を設けてなる絶縁被膜付き電磁鋼板であって、該絶縁被膜が接着性樹脂および発泡剤を含有し、該発泡剤の含有量が該接着性樹脂１００質量部に対して０．０１〜２質量部であることを特徴とする。
【００１３】
本発明の絶縁被膜付き電磁鋼板に用いられる電磁鋼板（電気鉄板）としては、公知のものを用いることができ、無方向性、１方向性、２方向性などいずれのものでもよい。電磁鋼板の化学組成は、特に限定されない。また、電磁鋼板の板厚は、特に限定されないが、通常の厚みである０．０５〜１．０ｍｍ程度とするのが好ましい。
【００１４】
本発明に用いられる接着性樹脂は、特に限定されず、アクリル系、エポキシ系、フェノール系、シリコーン系等の樹脂を用いることができ、これらを単独でまたは２種以上の接着性樹脂の混合物として用いることができる。また、アミン系硬化剤、シリカ等の添加物を本発明の効果を損なわない範囲で添加することができる。
本発明に用いられる接着性樹脂は、ガラス転移温度または軟化温度が６０℃以上であるのが好ましい。ガラス転移温度または軟化温度が６０℃以上であると、良好な接着強度が得られ、かつ、コイル状に巻き取った場合においても鋼板同士のブロッキングを抑制することができる。
【００１５】
本発明に用いられる発泡剤は、化学発泡剤であり、加熱により窒素、二酸化炭素、一酸化炭素、アンモニア、水素等のガスを発生させるものである。発泡剤としては、有機系発泡剤および無機系発泡剤のいずれも用いることができる。
有機系発泡剤としては、例えば、アゾジカルボンアミド、アゾビスホルムアミド、アゾビスイソブチロニトリル、アゾジカルポン酸バリウム等のアゾ化合物；Ｎ，Ｎ´−ジニトロソペンタメチレンテトラミン、Ｎ，Ｎ´−ジニトロソ−Ｎ，Ｎ´−ジメチルテレフタルアミド等のニトロソ化合物；ベンゼンスルホニルヒドラジッド、ｐ−トルエンスルホニルヒドラジッド、ｐ，ｐ´−オキシビスベンゼンスルホニルヒドラジッド等のスルホニルヒドラジッド化合物；ｐ−トルエンスルホニルセミカルバジッド等のスルホニルセミカルバジッド化合物；５−フェニルテトラゾール、５−フェニル−１Ｈ−テトラゾール等のテトラゾール化合物が挙げられる。
無機系発泡剤としては、例えば、重炭酸ナトリウム、炭酸アンモニウム、重炭酸アンモニウム、亜硝酸アンモニウム、カルシウムアジド等のアジド化合物；ホウ水素化ナトリウム；およびこれらに有機酸を添加したものが挙げられる。
これらの発泡剤は、本発明を損なわない範囲で、複合させて用いてもよい。
【００１６】
発泡剤の分解開始温度および分解温度は、特に限定されない。
ここで、本発明における分解開始温度および分解温度について、図３を用いて説明する。図３は、発泡剤を昇温速度２℃／分で加熱した場合の温度とガス発生量との関係を示すグラフである。本発明における発泡剤の分解開始温度は、昇温速度２℃／分で加熱した場合にガス発生量が急激に増加し始める温度であり、図３における接線ａと接線ｂとの交点の温度である。また、本発明における発泡剤の分解温度は昇温速度２℃／分で加熱した場合にガス発生量が飽和する温度であり、図３における接線ｃと接線ｄとの交点の温度である。
【００１７】
本発明の絶縁被膜付き電磁鋼板の絶縁被膜における発泡剤の含有量は、接着性樹脂１００質量部に対して０．０１〜２質量部である。
絶縁被膜における発泡剤の含有量は、絶縁被膜を十分に膨張させる点で、接着性樹脂１００質量部に対して、０．０１質量部以上であり、好ましくは０．０２質量部以上、より好ましくは０．０５質量部以上、更に好ましくは０．１０質量部以上である。
また、絶縁被膜における発泡剤の含有量は、被膜の密度を維持して接着強度を維持する点で、接着性樹脂１００質量部に対して、２質量部以下であり、好ましくは１．５質量部以下、より好ましくは１．０質量部以下である。
【００１８】
本発明の絶縁被膜付き電磁鋼板は、後述する本発明の積層電磁鋼板および本発明の積層鉄芯に好適に用いられるためには、発泡剤が接着性樹脂中に均一に分散し、接着後の膜厚より小さい気泡を生成させうるのが好ましい。
【００１９】
本発明の絶縁被膜付き電磁鋼板の絶縁被膜は、上記発泡剤の発泡に関する温度特性を調整するために、分解促進剤（発泡助剤）を含有することができる。分解促進剤としては、特に限定されず、用いられる発泡剤に応じて公知のものを用いることができる。例えば、尿素、ステアリン酸、二塩基性フタル酸鉛、二塩基性亜リン酸鉛、ルイス酸を有する金属化合物が挙げられる。
【００２０】
本発明の絶縁被膜付き電磁鋼板の絶縁被膜は、各種性能の一層の向上ために、防錆剤等の添加剤を含有することができる。この場合、歪取り焼鈍後の性能を確保するために、絶縁被膜における無機物質の合計量は、有機物質１００質量部に対して３〜３００質量部とするのが好ましい。
【００２１】
本発明の絶縁被膜付き電磁鋼板の絶縁被膜の厚さは、特に限定されないが、十分な層間抵抗を得られる点で、０．０５μｍ以上であるのが好ましく、０．１μｍ以上であるのがより好ましく、また、占積率（積層電磁鋼板や積層鉄芯とした場合の全体に対する地鉄の割合）を高く保つため、２５μｍ以下であるのが好ましく、１０μｍ以下であるのがより好ましい。
【００２２】
本発明の絶縁被膜付き電磁鋼板は、製造方法を特に限定されない。例えば、エマルジョン、ディスパージョン等の水系の接着性樹脂をロールコーター法、フローコーター法、スプレー塗装、ナイフコーター法等、種々の方法で電磁鋼板に塗布し、通常実施されるような熱風式、赤外式、誘導加熱式等の方法で焼付処理を行う方法が挙げられる。これらの工程は、電磁鋼板を切り板状としてから行ってもよいが、コイル状のままで行った方が生産性が高く、実用的である。
また、これらの工程は、用いられる発泡剤の分解温度以下、好ましくは分解開始温度以下で行う。これにより、製造工程での発泡剤の発泡を抑制し、本発明の絶縁被膜付き電磁鋼板を積層して加熱加圧した場合における発泡性能を担保することができる。したがって、本発明の絶縁被膜付き電磁鋼板は、発泡剤の少なくとも一部が発泡性能を有している。
【００２３】
本発明の絶縁被膜付き電磁鋼板は、積層し加熱加圧した場合に、発泡剤が発泡して絶縁被膜を膨張させて、絶縁被膜同士の間に隙間を生じることなく十分に密接に接着しうるので、接着不良による層間はく離を引き起こすことがない。
また、本発明の絶縁被膜付き電磁鋼板においては、製造の際に、絶縁性が低下したり、熱歪みや加工歪みにより磁気特性が劣化したりするという問題がなく、また、絶縁被膜形成後に更に接着剤を塗布する必要がないので、作業性が悪いという問題もない。
【００２４】
特開平４−２３５２８６号公報には、有機発泡剤等を配合した重クロム酸水溶液を塗布して得られる電気絶縁被膜を有する電磁鋼板が記載されている。この電磁鋼板は、被膜形成時に発泡剤を発泡させ、絶縁被膜層内に均一な気泡構造を生じさせたものである。しかし、この電磁鋼板を積層し加熱加圧することにより積層電磁鋼板を製造する場合には、従来の加熱接着型電磁鋼板と同様に、被膜表面の凹凸等から生じる接着不良の問題がある。
これに対し、本発明の絶縁被膜付き電磁鋼板は、被膜形成時等における発泡を抑制し発泡性能を担保したものであるので、積層して加熱加圧すると、発泡剤が発泡して絶縁被膜を膨張させて、絶縁被膜同士の間に隙間を生じることがないので、接着不良の問題がない。
【００２５】
つぎに、本発明の積層電磁鋼板について説明する。本発明の積層電磁鋼板は、電磁鋼板を２枚以上積層してなる積層電磁鋼板であって、各電磁鋼板の間に接着性樹脂を含有する接着層を有し、該接着層が接着層の厚さより径の小さい気泡を多数有することを特徴とする。本発明の積層電磁鋼板は、接着層が十分に強度を有し、接着不良による層間はく離等の問題がない。
【００２６】
本発明の積層電磁鋼板に用いられる電磁鋼板および接着性樹脂は、上述した本発明の絶縁被膜付き電磁鋼板に用いられるものと同様である。また、本発明の積層電磁鋼板の接着層は、本発明の絶縁被膜付き電磁鋼板の絶縁被膜と同様に、防錆剤等の添加剤を含有することができる。
【００２７】
本発明の積層電磁鋼板の接着層の厚さは、特に限定されないが、十分な層間抵抗を得られる点で、０．０５μｍ以上であるのが好ましく、０．１μｍ以上であるのがより好ましく、また、占積率を高く保つため、２５μｍ以下であるのが好ましく、１５μｍ以下であるのがより好ましい。
【００２８】
本発明の積層電磁鋼板の接着層は、接着層の厚さより径の小さい気泡を多数有する。気泡の径が接着層の厚さより大きいと、接着強度が弱くなる。
【００２９】
本発明の積層電磁鋼板は、製造方法を特に限定されず、例えば、本発明の絶縁被膜付き電磁鋼板を前記絶縁被膜同士が接着するように２枚以上積層した後、前記発泡剤の分解開始温度以上の温度になるように加熱加圧して、前記発泡剤の一部または全部を発泡させることを特徴とする、本発明の積層電磁鋼板の製造方法が好適に挙げられる。以下、本発明の積層電磁鋼板の製造方法について説明する。
【００３０】
本発明の積層電磁鋼板の製造方法においては、まず本発明の絶縁被膜付き電磁鋼板を前記絶縁被膜同士が接着するように２枚以上積層する。ここで、本発明の絶縁被膜付き電磁鋼板が、両面に絶縁被膜を有している場合は、その両側に他の本発明の絶縁被膜付き電磁鋼板を積層することができる。したがって、積層する両端の２枚以外の絶縁被膜付き電磁鋼板を両面に絶縁被膜を有するものとすることにより、所望の枚数を積層することができる。
【００３１】
つぎに、前記発泡剤の分解開始温度以上の温度になるように加熱加圧して、前記発泡剤の一部または全部を発泡させる。発泡剤を発泡させ、気泡を多数生じさせることにより絶縁被膜を膨張させて、絶縁被膜同士の間に隙間を生じさせることなく接着させることができる。
本発明の積層電磁鋼板の製造方法においては、加熱温度は、用いられる発泡剤の分解開始温度以上であれば特に限定されないが、用いられる接着性樹脂のガラス転移温度または軟化温度以上であるのが好ましく、また、接着性樹脂の分解温度以下であるのが好ましい。
【００３２】
接着圧力は、０．０１ｋｇｆ／ｃｍ2 （９．８１×１０2 Ｐａ）以上であるのが好ましく、１ｋｇｆ／ｃｍ2 （９．８１×１０4 Ｐａ）以上であるのがより好ましく、５ｋｇｆ／ｃｍ2 （４．９０×１０5 Ｐａ）以上であるのが特に好ましく、また、２０００ｋｇｆ／ｃｍ2 （１．９６１×１０8 Ｐａ）以下であるのが好ましく、１０００ｋｇｆ／ｃｍ2 （９．８１×１０7 Ｐａ）以下であるのがより好ましく、５００ｋｇｆ／ｃｍ2 （４．９０×１０7 Ｐａ）以下であるのが特に好ましい。本発明の積層電磁鋼板の製造方法によれば、接着性樹脂を含有する絶縁被膜が膨張するため、従来の加熱接着型電磁鋼板に比べて、より低い接着圧力で十分な接着状態を実現することができる。
加圧時間は、１０〜１００００秒であるのが好ましい。
【００３３】
本発明の積層電磁鋼板の用途は、特に限定されないが、積層鉄芯とするのが好ましい態様の一つである。即ち、電磁鋼板を２枚以上積層してなる積層鉄芯であって、各電磁鋼板の間に接着性樹脂を含有する接着層を有し、該接着層が接着層の厚さより径の小さい気泡を多数有する積層鉄芯は、本発明の一態様である。
本発明の積層電磁鋼板は、表面に接着性樹脂層があることを利用して、更に加熱加圧してブロック化することが好ましいが、加熱加圧せずに他の方法（カシメ、溶接）により積層固着して使用してもかまわない。本発明の積層電磁鋼板は、電磁鋼板を加熱加圧により積層して得られるものなので、これを他の方法により積層固着する場合でも、打抜き、積層回数の手間が少ないという利点がある。
また、本発明の積層電磁鋼板の製造方法の用途は、特に限定されないが、本発明の積層鉄芯の製造方法とするのが好ましい態様の一つである。即ち、本発明の絶縁被膜付き電磁鋼板を前記絶縁被膜同士が接着するように２枚以上積層した後、前記発泡剤の分解開始温度以上の温度になるように加熱加圧して、前記発泡剤の一部または全部を発泡させることにより積層鉄芯を得ることを特徴とする積層電磁鋼板の製造方法は、本発明の一態様である。
【００３４】
【実施例】
以下に実施例を示して本発明を具体的に説明するが、本発明はこれらに限られるものではない。
（実施例１〜１８および比較例１〜５）
大きさ１５０ｍｍ×３００ｍｍ、板厚０．５ｍｍの電磁鋼板（電気鉄板）に、第１表に示すように、各種の発泡剤を所定の含有量で含有する各種の水系の接着性樹脂をロールコーターで塗布し、到達板温１８０℃で焼き付け、放冷して、被膜厚さ５μｍの絶縁被膜を一方の表面に有する絶縁被膜付き電磁鋼板を得た。
つぎに、絶縁被膜付き電磁鋼板を絶縁被膜同士が接着するように２枚積層した後、ホットプレスを用いて、第１表に示す温度で、圧力１０ｋｇｆ／ｃｍ2 （９．８１×１０5 Ｐａ）、時間１分の条件で加熱加圧して接着させて、積層電磁鋼板を得た。
【００３５】
得られた各絶縁被膜付き電磁鋼板および各積層電磁鋼板について、以下のようにして評価を行った。
（１）接着強度
２枚の絶縁被膜付き電磁鋼板（幅２０ｍｍ×長さ７０ｍｍ）を、先端から１０ｍｍまでの部分で絶縁被膜同士が接着するように、ずらして積層した後（ラップ部分：幅２０ｍｍ×長さ１０ｍｍ）、ホットプレスを用いて、２００℃で、圧力１０ｋｇｆ／ｃｍ2 （９．８１×１０5 Ｐａ）、時間１分の条件で加熱加圧して接着させ、試験片を得た。この試験片について、引張速度３ｍｍ／ｍｉｎの条件で室温で引張試験を行い、破断したときの最大応力により接着強度を評価した。
【００３６】
（２）接着面の状態
積層電磁鋼板（５０ｍｍ×５０ｍｍ）について、接着した層間にクサビを打ち込んで接着面ではく離させ、接着面の状態を目視により観察し、以下のように評価した。
◎：ほぼ全面積が接着
○：面積の９０％以上が接着
△：面積の７０％以上９０％未満が接着
×：面積の７０％未満が接着
【００３７】
（３）気密性
上記で得られた一方の表面に絶縁被膜を有する絶縁被膜付き電磁鋼板２枚と、上記と同様の条件で製造された被膜厚さ５μｍの絶縁被膜を両方の表面に有する絶縁被膜付き電磁鋼板３８枚との合計４０枚を、それぞれリング状（外径１００ｍｍ、内径５０ｍｍ）に打ち抜いた後、絶縁被膜同士が接着するように積層し、上記と同様の条件で加熱加圧して、積層鉄芯を得た。
つぎに、図４（ａ）に模式的に示した、上記で得られた各積層鉄芯３０について、図４（ｂ）に示すようにして気密性試験を行った。
積層鉄芯３０の上面および下面をステンレス製のシール３１および３２でシールした。ただし、上面のシール３１には、空気を送るための管３３を取り付けた。ついで、シール後の積層鉄芯３０を水３４を入れた容器に浸せきさせ、上面のシール３１に取り付けた管３３から、圧縮空気を圧力が１ｋｇｆ／ｃｍ2 （９．８１×１０4 Ｐａ）を保つように注入し、単位時間あたりに積層鉄芯３０の側面から漏れた空気３５をメスシリンダー３６に溜めて、その量を測定した。なお、いずれの積層鉄芯３０についての試験においても、積層鉄芯３０と上下のシール３１および３２との間からは空気は漏れていなかった。
【００３８】
接着強度、接着面の状態および気密性の評価結果を第１表に示す。また、５−フェニルテトラゾールを含有するアクリル系樹脂を用いたもの（実施例１〜８ならびに比較例２および３）については、接着強度および接着面の状態を図５にも示した。
第１表および図５から明らかなように、本発明の絶縁被膜付き電磁鋼板（実施例１〜１８）は、積層して加熱加圧して接着させて、本発明の積層電磁鋼板や本発明の積層鉄芯とした場合に、いずれも接着性に優れ、かつ、接着面の状態がよいことが分かる。なお、実施例１〜１８の積層電磁鋼板について、接着層を接着面ではく離させた後に、電子顕微鏡によりその断面を観察したところ、いずれも接着層が接着層の厚さより径の小さい気泡を多数有していた。
これに対して、接着性樹脂が発泡剤を含有しない従来の加熱接着型電磁鋼板（比較例１、４および５）は、接着性が悪く、非接着部分が多かった。発泡剤の含有量が少なすぎる場合（比較例２）も同様であった。また、発泡剤の含有量が多すぎる場合（比較例３）は、接着強度に劣っていた。
【００３９】
【表１】
【表２】
第１表中、各接着性樹脂の組成は、以下の通りである。
▲１▼アクリル系樹脂：アクリル樹脂８５質量％（ガラス転移温度８０℃）、エポキシ樹脂１５質量％
▲２▼エポキシ系樹脂：エポキシ樹脂８５質量％（軟化温度７０℃）、フェノール樹脂１５質量％
▲３▼アクリル／エポキシ系樹脂：アクリル樹脂４０質量％（ガラス転移温度８０℃）、エポキシ樹脂３０質量％（軟化温度７０℃）、フェノール樹脂３０質量％
【００４２】
【発明の効果】
本発明の絶縁被膜付き電磁鋼板は、積層し加熱加圧した場合に、絶縁被膜同士が十分に密接に接着しうる。また、本発明の積層電磁鋼板および本発明の積層鉄芯は、接着層における接着性に優れる。更に、本発明の積層電磁鋼板の製造方法および本発明の積層鉄芯の製造方法によれば、本発明の積層電磁鋼板および本発明の積層鉄芯を好適に製造することができる。
【図面の簡単な説明】
【図１】従来の加熱接着型電磁鋼板を積層し、加熱加圧して得られる積層鉄芯における、接着性樹脂を含有する絶縁被膜の模式的な断面図である。
【図２】（ａ）は、従来の加熱接着型電磁鋼板を積層してなる積層電磁鋼板の加熱加圧前後の状態を示す断面模式図であり、（ｂ）は、本発明の絶縁被膜付き電磁鋼板を積層してなる積層電磁鋼板の加熱加圧前後の状態を示す断面模式図である。
【図３】発泡剤を昇温速度２℃／分で加熱した場合の温度とガス発生量との関係を示すグラフである。
【図４】（ａ）は、積層鉄芯の模式的な斜視図であり、（ｂ）は、積層鉄芯の気密性試験の説明図である。
【図５】本発明の実施例および比較例の一部における、発泡剤含有量と接着強度および接着面の状態のそれぞれとの関係を示す図である。
【符号の説明】
１ 積層鉄芯
２、１２ 接着性樹脂被膜（接着性樹脂を含有する絶縁被膜）
３、１３ 接着良好部分
４、１４ 非接着部分
５ コア割れ部分
１０ 従来の加熱接着型電磁鋼板
１１、２１ 電磁鋼板
２０ 本発明の絶縁被膜付き電磁鋼板
２２ 接着性樹脂および発泡剤を含有する絶縁被膜
２３ 気泡
３０ 積層鉄芯
３１ 上面のシール
３２ 下面のシール
３３ 管
３４ 水
３５ 漏れた空気
３６ メスシリンダー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat-bonded electrical steel sheet with an insulating coating used as a material for a laminated iron core used in a rotor, a transformer, and the like. The present invention also relates to a laminated electrical steel sheet, a laminated iron core, and methods for producing them.
[0002]
[Prior art]
Conventionally, iron cores used in electrical equipment such as rotors and transformers are first coated with an insulating coating to reduce eddy currents on a magnetic steel sheet, punched or sheared, stacked in large numbers, and welded. It was manufactured by fixing with caulking or adhesive.
However, the method of fixing by welding has a problem that the iron core edge portion is short-circuited and the insulating property is lowered, and a magnetic property is deteriorated due to thermal strain. Further, the method of fixing by caulking has a problem that the magnetic characteristics are deteriorated due to processing strain. In addition, the method of fixing with an adhesive does not have much of the problem of deterioration of magnetic properties as described above. However, since it is necessary to apply an adhesive to each magnetic steel sheet, there is a problem that workability is poor, or insulation. There was a problem that the adhesive strength between the coatings was not sufficient.
[0003]
On the other hand, in JP-A-2-208034, a steel plate obtained by applying and drying a composition mainly composed of a thermoplastic acrylic resin emulsion, an epoxy resin emulsion or the like having a glass transition temperature of 60 ° C. or higher is laminated. And a method for producing a laminated iron core by heating and pressing is described. This method omits the step of applying an adhesive, has the advantage that it is less susceptible to processing distortion and is less likely to block even when coiled.
However, in the actual laminated iron core obtained by heating and pressurizing the electromagnetic steel sheet manufactured by the above method (hereinafter referred to as “conventional heat-bonded electromagnetic steel sheet”), there is a case where there is an incompletely bonded portion. In severe cases, there was a problem of causing delamination (separation on the adhesion surface) due to poor adhesion. In particular, when the iron core is large, it is easily affected by the unevenness of the coating film and the steel plate, and the problem is easily manifested.
[0004]
This will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of an insulating coating 2 containing an adhesive resin in a laminated iron core 1 obtained by laminating conventional heat-bonded electrical steel sheets and heating and pressing. Even before the bonding, the surface of the insulating coating 2 appears to be quite flat in appearance, or there are subtle irregularities of the ridge-like coating due to roping of the coating roll at the time of coating. The recess may not adhere. As a result, the good adhesion portion 3 and the non-adhesion portion 4 are present in a striped shape, and it may not be possible to achieve complete adhesion. This is a cause of leakage when it is desired to seal the inside and outside of the laminated core of the laminated iron core 1. In addition, in portions where pressure is insufficient due to reasons such as plate thickness deviation and film thickness deviation, the insulating coatings 2 may not sufficiently adhere to each other, and core cracks may occur. The
[0005]
[Problems to be solved by the invention]
Therefore, the present invention provides an electromagnetic steel sheet having an insulating coating containing an adhesive resin on the surface, and when the laminated coating is heated and pressed, the insulating coating can sufficiently adhere to each other. Objective.
Further, the present invention is a laminated electromagnetic steel sheet obtained by laminating two or more electromagnetic steel sheets, wherein the electromagnetic steel sheets are sufficiently bonded together by an adhesive layer containing an adhesive resin between the electromagnetic steel sheets. It aims at providing a steel plate and its manufacturing method.
Furthermore, the present invention is a laminated iron core obtained by laminating two or more electromagnetic steel sheets, and the laminated irons in which the electromagnetic steel sheets are sufficiently bonded together by an adhesive layer containing an adhesive resin between the electromagnetic steel sheets. It is an object of the present invention to provide a core and a method for manufacturing the same.
[0006]
[Means for Solving the Problems]
As a result of diligent research to solve the above-mentioned problems, the present inventor has included a specific amount of a foaming agent in the adhesive resin constituting the insulating coating, and the foaming agent foams during heating and pressurization, and the insulating coating is formed. The present invention was completed by finding that no non-adhered portion was generated by expansion.
[0007]
That is, the present invention is an electrical steel sheet with an insulating coating in which an insulating coating is provided on at least one surface of the electrical steel sheet, the insulating coating containing an adhesive resin and a foaming agent, and the content of the foaming agent is Provided is an electrical steel sheet with an insulating coating that is 0.01 to 2 parts by mass with respect to 100 parts by mass of the adhesive resin.
FIG. 2 shows the above-mentioned (a) laminated electromagnetic steel sheet obtained by laminating conventional heat-bonded electromagnetic steel sheets, and (b) before and after heating and pressing of the laminated electromagnetic steel sheet obtained by laminating the electromagnetic steel sheets with insulating coatings of the present invention. It is a cross-sectional schematic diagram which shows the state. In addition, the electrical steel sheet with an insulating coating of this invention is not limited to this.
A conventional heat-bonded
[0008]
The present invention also provides:After laminating two or more electromagnetic steel sheets with insulating coatings so that the insulating coatings adhere to each other, heat and press so that the temperature is equal to or higher than the decomposition start temperature of the foaming agent, and part or all of the foaming agent is A laminated electrical steel sheet obtained by foaming is provided.
[0009]
The present invention also provides:After laminating two or more electromagnetic steel sheets with insulating coatings so that the insulating coatings adhere to each other, heat and press so that the temperature is equal to or higher than the decomposition start temperature of the foaming agent, and part or all of the foaming agent is Provided is a laminated iron core obtained by foaming.
[0010]
Further, the present invention provides a method in which the electrical steel sheet with an insulating coating is laminated so that the insulating coatings are bonded to each other, and then heated and pressed so that the temperature is equal to or higher than a decomposition start temperature of the foaming agent, and the foaming is performed. Provided is a method for producing a laminated electrical steel sheet, characterized in that a laminated electrical steel sheet is obtained by foaming part or all of the agent.
[0011]
Further, the present invention provides a method in which the electrical steel sheet with an insulating coating is laminated so that the insulating coatings are bonded to each other, and then heated and pressed so that the temperature is equal to or higher than a decomposition start temperature of the foaming agent, and the foaming is performed. Provided is a method for producing a laminated iron core, wherein a laminated iron core is obtained by foaming part or all of the agent.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
First, the electrical steel sheet with an insulating coating according to the present invention will be described. The electrical steel sheet with an insulating coating of the present invention is an electrical steel sheet with an insulating coating formed by providing an insulating coating on at least one surface of the electrical steel sheet, the insulating coating containing an adhesive resin and a foaming agent, and the foaming agent The content of is 0.01 to 2 parts by mass with respect to 100 parts by mass of the adhesive resin.
[0013]
As the electrical steel sheet (electric iron plate) used for the electrical steel sheet with an insulating coating of the present invention, a known one can be used, and any of non-directional, unidirectional, bi-directional, etc. may be used. The chemical composition of the electrical steel sheet is not particularly limited. Moreover, the plate | board thickness of an electromagnetic steel plate is although it does not specifically limit, It is preferable to set it as about 0.05-1.0 mm which is normal thickness.
[0014]
The adhesive resin used in the present invention is not particularly limited, and acrylic, epoxy, phenolic, silicone and other resins can be used alone or as a mixture of two or more adhesive resins. Can be used. Additives such as amine-based curing agents and silica can be added within a range that does not impair the effects of the present invention.
The adhesive resin used in the present invention preferably has a glass transition temperature or a softening temperature of 60 ° C. or higher. When the glass transition temperature or softening temperature is 60 ° C. or higher, good adhesive strength can be obtained, and blocking between steel plates can be suppressed even when the glass transition temperature or the softening temperature is coiled.
[0015]
The foaming agent used in the present invention is a chemical foaming agent, and generates gas such as nitrogen, carbon dioxide, carbon monoxide, ammonia, and hydrogen by heating. As the foaming agent, either an organic foaming agent or an inorganic foaming agent can be used.
Examples of the organic foaming agent include azo compounds such as azodicarbonamide, azobisformamide, azobisisobutyronitrile, barium azodicarboxylate; N, N′-dinitrosopentamethylenetetramine, N, N′-dinitroso- Nitroso compounds such as N, N′-dimethylterephthalamide; sulfonyl hydrazide compounds such as benzenesulfonyl hydrazide, p-toluenesulfonyl hydrazide, p, p′-oxybisbenzenesulfonyl hydrazide; p-toluenesulfonyl semicarbazide Sulfonyl semicarbazide compounds such as; tetrazole compounds such as 5-phenyltetrazole and 5-phenyl-1H-tetrazole.
Examples of the inorganic foaming agent include azide compounds such as sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, ammonium nitrite, and calcium azide; sodium borohydride; and those obtained by adding an organic acid thereto.
These foaming agents may be used in combination as long as the present invention is not impaired.
[0016]
The decomposition start temperature and decomposition temperature of the foaming agent are not particularly limited.
Here, the decomposition start temperature and the decomposition temperature in the present invention will be described with reference to FIG. FIG. 3 is a graph showing the relationship between the temperature and the amount of gas generated when the foaming agent is heated at a heating rate of 2 ° C./min. The decomposition start temperature of the foaming agent in the present invention is a temperature at which the amount of gas generation starts to increase rapidly when heated at a heating rate of 2 ° C./min, and is the temperature at the intersection of tangent line a and tangent line b in FIG. is there. Further, the decomposition temperature of the foaming agent in the present invention is a temperature at which the amount of gas generation is saturated when heated at a heating rate of 2 ° C./min, and is the temperature at the intersection of tangent c and tangent d in FIG.
[0017]
The content of the foaming agent in the insulating coating of the electrical steel sheet with an insulating coating of the present invention is 0.01 to 2 parts by mass with respect to 100 parts by mass of the adhesive resin.
The content of the foaming agent in the insulating coating is 0.01 parts by mass or more, preferably 0.02 parts by mass or more, more preferably, with respect to 100 parts by mass of the adhesive resin, in that the insulating coating is sufficiently expanded. Is 0.05 parts by mass or more, more preferably 0.10 parts by mass or more.
The content of the foaming agent in the insulating coating is 2 parts by mass or less, preferably 1.5 parts by mass with respect to 100 parts by mass of the adhesive resin in terms of maintaining the density of the coating and maintaining the adhesive strength. Part or less, more preferably 1.0 part by weight or less.
[0018]
In order for the electrical steel sheet with an insulating coating of the present invention to be suitably used for the laminated electrical steel sheet of the present invention and the laminated iron core of the present invention to be described later, the foaming agent is uniformly dispersed in the adhesive resin. It is preferable that bubbles smaller than the film thickness can be generated.
[0019]
The insulating coating of the electrical steel sheet with an insulating coating of the present invention can contain a decomposition accelerator (foaming aid) in order to adjust the temperature characteristics related to foaming of the foaming agent. The decomposition accelerator is not particularly limited, and a known one can be used depending on the foaming agent used. For example, a metal compound having urea, stearic acid, dibasic lead phthalate, dibasic lead phosphite, or Lewis acid can be used.
[0020]
The insulating coating of the electrical steel sheet with an insulating coating of the present invention can contain additives such as a rust preventive agent in order to further improve various performances. In this case, in order to ensure the performance after strain relief annealing, the total amount of the inorganic substance in the insulating coating is preferably 3 to 300 parts by mass with respect to 100 parts by mass of the organic substance.
[0021]
The thickness of the insulating coating of the electrical steel sheet with an insulating coating of the present invention is not particularly limited, but is preferably 0.05 μm or more and more preferably 0.1 μm or more in terms of obtaining sufficient interlayer resistance. Moreover, in order to keep the space factor (the ratio of the ground iron to the whole in the case of a laminated electromagnetic steel sheet or a laminated iron core) high, it is preferably 25 μm or less, and more preferably 10 μm or less.
[0022]
The manufacturing method of the electrical steel sheet with an insulating coating of the present invention is not particularly limited. For example, water-based adhesive resins such as emulsions and dispersions are applied to electrical steel sheets by various methods such as roll coater method, flow coater method, spray coating, knife coater method, etc. Examples of the method include baking by an external method, an induction heating method, and the like. These steps may be performed after the electromagnetic steel sheet is cut into a plate shape, but it is more practical and more practical to perform it in the coil shape.
Further, these steps are performed at a temperature lower than the decomposition temperature of the foaming agent used, preferably lower than the decomposition start temperature. Thereby, foaming of the foaming agent in a manufacturing process can be suppressed, and the foaming performance in the case of laminating and heating and pressurizing the electromagnetic steel sheets with insulating coatings of the present invention can be ensured. Therefore, in the electrical steel sheet with an insulating coating of the present invention, at least a part of the foaming agent has foaming performance.
[0023]
The electrical steel sheet with an insulating coating of the present invention, when laminated and heated and pressed, expands the insulating coating by foaming, and can adhere sufficiently closely without causing a gap between the insulating coatings. Therefore, it does not cause delamination due to poor adhesion.
In addition, in the electrical steel sheet with an insulating coating of the present invention, there is no problem that the insulating property is lowered during the production or the magnetic properties are deteriorated due to thermal strain or processing strain, and further after the insulating coating is formed. Since there is no need to apply an adhesive, there is no problem of poor workability.
[0024]
Japanese Patent Application Laid-Open No. 4-235286 describes an electrical steel sheet having an electrical insulating film obtained by applying a dichromic acid aqueous solution blended with an organic foaming agent or the like. In this electrical steel sheet, a foaming agent is foamed at the time of film formation, and a uniform cell structure is generated in the insulating coating layer. However, when a laminated electromagnetic steel sheet is manufactured by laminating and heating and pressing the electromagnetic steel sheets, there is a problem of adhesion failure caused by unevenness on the surface of the coating film as in the case of conventional heat-bonded electromagnetic steel sheets.
On the other hand, the electrical steel sheet with an insulating coating of the present invention suppresses foaming at the time of coating formation and ensures foaming performance. Therefore, when laminated and heated and pressurized, the foaming agent foams to form an insulating coating. Since there is no gap between the insulating coatings due to expansion, there is no problem of poor adhesion.
[0025]
Next, the laminated electrical steel sheet of the present invention will be described. The laminated electrical steel sheet of the present invention is a laminated electrical steel sheet obtained by laminating two or more electrical steel sheets, and has an adhesive layer containing an adhesive resin between the electrical steel sheets, and the adhesive layer is an adhesive layer. It has a large number of bubbles having a diameter smaller than the thickness. In the laminated electrical steel sheet of the present invention, the adhesive layer has sufficient strength, and there is no problem such as delamination due to poor adhesion.
[0026]
The electrical steel sheet and the adhesive resin used for the laminated electrical steel sheet of the present invention are the same as those used for the above-described electrical steel sheet with an insulating coating of the present invention. Moreover, the adhesive layer of the laminated electrical steel sheet of the present invention can contain additives such as a rust preventive agent in the same manner as the insulating film of the electrical steel sheet with an insulating film of the present invention.
[0027]
The thickness of the adhesive layer of the laminated electrical steel sheet of the present invention is not particularly limited, but it is preferably 0.05 μm or more, more preferably 0.1 μm or more, in terms of obtaining sufficient interlayer resistance. Further, in order to keep the space factor high, it is preferably 25 μm or less, and more preferably 15 μm or less.
[0028]
The adhesive layer of the laminated electrical steel sheet according to the present invention has many bubbles having a diameter smaller than the thickness of the adhesive layer. When the bubble diameter is larger than the thickness of the adhesive layer, the adhesive strength is weakened.
[0029]
The production method of the laminated electrical steel sheet of the present invention is not particularly limited. For example, after laminating two or more electromagnetic steel sheets with an insulating coating of the present invention so that the insulating coatings adhere to each other, the decomposition start temperature of the foaming agent A method for producing a laminated electrical steel sheet according to the present invention is preferably mentioned in which part or all of the foaming agent is foamed by heating and pressurizing so as to achieve the above temperature. Hereinafter, the manufacturing method of the laminated electrical steel sheet of this invention is demonstrated.
[0030]
In the method for producing a laminated electrical steel sheet according to the present invention, first, two or more electromagnetic steel sheets with an insulating coating according to the present invention are laminated so that the insulating coatings adhere to each other. Here, when the electrical steel sheet with an insulation coating of the present invention has an insulation coating on both surfaces, the other electrical steel sheet with an insulation coating of the present invention can be laminated on both sides thereof. Therefore, a desired number of sheets can be laminated by providing the insulating steel sheets with insulating coatings on both sides other than the two sheets at both ends to be laminated.
[0031]
Next, it heats and pressurizes so that it may become the temperature beyond the decomposition start temperature of the said foaming agent, and foams one part or all part of the said foaming agent. The insulating film can be expanded by foaming the foaming agent and generating a large number of bubbles, and can be bonded without causing a gap between the insulating films.
In the method for producing a laminated electrical steel sheet of the present invention, the heating temperature is not particularly limited as long as it is equal to or higher than the decomposition start temperature of the foaming agent used, but it is equal to or higher than the glass transition temperature or softening temperature of the adhesive resin used. Moreover, it is preferable that it is below the decomposition temperature of adhesive resin.
[0032]
Adhesion pressure is 0.01kgf / cm2(9.81 × 102Pa) or higher, preferably 1 kgf / cm2(9.81 × 10FourPa) or more, more preferably 5 kgf / cm2(4.90x10FivePa) or more is particularly preferable, and 2000 kgf / cm.2(1.961 × 108Pa) or less, preferably 1000 kgf / cm2(9.81 × 107Pa) or less, more preferably 500 kgf / cm2(4.90x107Pa) is particularly preferred. According to the method for producing a laminated electrical steel sheet of the present invention, since an insulating coating containing an adhesive resin expands, a sufficient adhesive state can be realized with a lower adhesive pressure as compared with a conventional heat-bonded electrical steel sheet. Can do.
The pressing time is preferably 10 to 10,000 seconds.
[0033]
The use of the laminated electrical steel sheet of the present invention is not particularly limited, but it is one of the preferred embodiments that a laminated iron core is used. That is, a laminated iron core formed by laminating two or more electromagnetic steel sheets, and has an adhesive layer containing an adhesive resin between each electromagnetic steel sheet, and the adhesive layer has a smaller diameter than the thickness of the adhesive layer A laminated iron core having a large number of is an embodiment of the present invention.
The laminated electrical steel sheet of the present invention is preferably further heated and pressed to form a block using the adhesive resin layer on the surface, but by other methods (caulking, welding) without heating and pressing. It may be used after being laminated. Since the laminated electrical steel sheet of the present invention is obtained by laminating electrical steel sheets by heating and pressing, there is an advantage that there is less time for punching and laminating even when the steel sheet is laminated and fixed by other methods.
The use of the method for producing a laminated electrical steel sheet according to the present invention is not particularly limited, but it is one of the preferred embodiments that the method for producing a laminated iron core according to the present invention is used. That is, after laminating two or more electrical steel sheets with insulating coatings of the present invention so that the insulating coatings adhere to each other, heat and pressure is applied so that the temperature is equal to or higher than the decomposition start temperature of the foaming agent. A method for producing a laminated electrical steel sheet, wherein a laminated iron core is obtained by foaming part or all, is an embodiment of the present invention.
[0034]
【Example】
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
(Examples 1-18 and Comparative Examples 1-5)
As shown in Table 1, various water-based adhesive resins containing various foaming agents with a predetermined content are rolled into a roll coater on a magnetic steel sheet (electric iron plate) having a size of 150 mm × 300 mm and a plate thickness of 0.5 mm. Then, it was baked at an ultimate plate temperature of 180 ° C. and allowed to cool to obtain an electrical steel sheet with an insulating coating having an insulating coating with a film thickness of 5 μm on one surface.
Next, after laminating two sheets of insulating steel sheets with insulating coatings so that the insulating coatings adhere to each other, using a hot press, the temperature shown in Table 1 and the pressure of 10 kgf / cm2(9.81 × 10FivePa), and heated and pressed under conditions of 1 minute for time to obtain a laminated electrical steel sheet.
[0035]
Each obtained electrical steel sheet with an insulating coating and each laminated electrical steel sheet were evaluated as follows.
(1) Adhesive strength
After laminating and laminating two magnetic steel sheets with insulation coating (
[0036]
(2) Bonded surface condition
Regarding the laminated electromagnetic steel sheet (50 mm × 50 mm), wedges were driven between the adhered layers and peeled off from the bonded surface, and the state of the bonded surface was visually observed and evaluated as follows.
◎: Almost all area is bonded
○: 90% or more of the area is bonded
Δ: 70% or more and less than 90% of the area is bonded
X: Less than 70% of the area is bonded
[0037]
(3) Airtightness
Two electrical steel sheets with insulating coatings having an insulating coating on one surface obtained above, and an electrical steel sheet with insulating coatings 38 having an insulating coating with a thickness of 5 μm produced on both surfaces, manufactured under the same conditions as above. A total of 40 sheets are punched into a ring shape (
Next, an airtightness test was performed as shown in FIG. 4B for each of the
The upper and lower surfaces of the
[0038]
Table 1 shows the evaluation results of the adhesive strength, the state of the adhesive surface and the airtightness. Moreover, about what used the acrylic resin containing 5-phenyltetrazole (Examples 1-8 and Comparative Examples 2 and 3), the adhesive strength and the state of the adhesive surface were also shown in FIG.
As is apparent from Table 1 and FIG. 5, the electrical steel sheets with insulating coatings of the present invention (Examples 1 to 18) were laminated, heated and pressed, and bonded to each other to obtain the laminated electrical steel sheets of the present invention and In the case of a laminated iron core, it can be seen that both are excellent in adhesiveness and the state of the adhesive surface is good. In addition, about the laminated electrical steel sheets of Examples 1 to 18, when the cross section was observed with an electron microscope after the adhesive layer was peeled off at the adhesive surface, all of the adhesive layer had many bubbles whose diameter was smaller than the thickness of the adhesive layer. Had.
On the other hand, the conventional heat-bonded electrical steel sheet (Comparative Examples 1, 4 and 5) in which the adhesive resin does not contain a foaming agent has poor adhesiveness and many non-bonded portions. The same was true when the foaming agent content was too low (Comparative Example 2). Moreover, when there was too much content of a foaming agent (comparative example 3), it was inferior to adhesive strength.
[0039]
[Table 1]
[Table 2]
In Table 1, the composition of each adhesive resin is as follows.
(1) Acrylic resin: 85% by mass of acrylic resin (glass transition temperature 80 ° C.), 15% by mass of epoxy resin
(2) Epoxy resin: epoxy resin 85% by mass (softening temperature 70 ° C.), phenol resin 15% by mass
(3) Acrylic / epoxy resin: acrylic resin 40% by mass (glass transition temperature 80 ° C.),
[0042]
【The invention's effect】
When the magnetic steel sheet with an insulating coating of the present invention is laminated and heated and pressed, the insulating coatings can adhere to each other sufficiently closely. Moreover, the laminated electrical steel sheet of the present invention and the laminated iron core of the present invention are excellent in adhesiveness in the adhesive layer. Furthermore, according to the manufacturing method of the laminated electromagnetic steel sheet of the present invention and the manufacturing method of the laminated iron core of the present invention, the laminated electromagnetic steel sheet of the present invention and the laminated iron core of the present invention can be suitably manufactured.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of an insulating coating containing an adhesive resin in a laminated iron core obtained by laminating conventional heat-bonded electrical steel sheets and heating and pressing.
FIG. 2 (a) is a schematic cross-sectional view showing a state before and after heating and pressing of a laminated electrical steel sheet obtained by laminating conventional heat-bonded electrical steel sheets, and FIG. 2 (b) is a diagram with an insulating coating of the present invention. It is a cross-sectional schematic diagram which shows the state before and behind the heating pressurization of the lamination | stacking electromagnetic steel plate formed by laminating | stacking an electromagnetic steel plate.
FIG. 3 is a graph showing a relationship between a temperature and a gas generation amount when a foaming agent is heated at a temperature rising rate of 2 ° C./min.
4A is a schematic perspective view of a laminated iron core, and FIG. 4B is an explanatory diagram of a hermeticity test of the laminated iron core.
FIG. 5 is a diagram showing the relationship between the foaming agent content, adhesive strength, and the state of the adhesive surface in some examples and comparative examples of the present invention.
[Explanation of symbols]
1 Laminated iron core
2,12 Adhesive resin film (insulating film containing adhesive resin)
3,13 Good adhesion part
4, 14 Non-adhesive part
5 Core breakage
10 Conventional heat-bonded electrical steel sheet
11, 21 Electrical steel sheet
20 Electrical steel sheet with insulating coating of the present invention
22 Insulating coating containing adhesive resin and foaming agent
23 Bubble
30 laminated iron core
31 Top seal
32 Bottom seal
33 tubes
34 Water
35 Leaked air
36 graduated cylinder
Claims (5)
Priority Applications (1)
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| JP2001054325A JP4572474B2 (en) | 2001-02-28 | 2001-02-28 | Electrical steel sheet with insulating coating with excellent adhesion |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001054325A JP4572474B2 (en) | 2001-02-28 | 2001-02-28 | Electrical steel sheet with insulating coating with excellent adhesion |
Publications (2)
| Publication Number | Publication Date |
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| JP2002260910A JP2002260910A (en) | 2002-09-13 |
| JP4572474B2 true JP4572474B2 (en) | 2010-11-04 |
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| JP2001054325A Expired - Fee Related JP4572474B2 (en) | 2001-02-28 | 2001-02-28 | Electrical steel sheet with insulating coating with excellent adhesion |
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| TWI261623B (en) * | 2003-09-26 | 2006-09-11 | Mitsui Chemicals Inc | Laminate from magnetic base material, and method for production thereof |
| JP4860480B2 (en) * | 2004-10-18 | 2012-01-25 | 新日本製鐵株式会社 | Electrical steel sheet with heat-resistant adhesive coating coated with heat-resistant adhesive film, iron core using the electrical steel sheet, and manufacturing method thereof |
| WO2024053732A1 (en) * | 2022-09-08 | 2024-03-14 | 日本製鉄株式会社 | Laminated core and method for manufacturing laminated core |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04235286A (en) * | 1991-01-08 | 1992-08-24 | Kawasaki Steel Corp | Magnetic steel sheet having electric insulating film of good weldability |
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2001
- 2001-02-28 JP JP2001054325A patent/JP4572474B2/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04235286A (en) * | 1991-01-08 | 1992-08-24 | Kawasaki Steel Corp | Magnetic steel sheet having electric insulating film of good weldability |
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| JP2002260910A (en) | 2002-09-13 |
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