JP4081230B2 - Electrical steel sheet with excellent magnetic properties suitable for mold cores - Google Patents
Electrical steel sheet with excellent magnetic properties suitable for mold cores Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、モールドされたモーター、モールドトランスやダイレクトイグニッションなどの樹脂モールドコア製品に適した電磁鋼板に関するものである。
【０００２】
【従来の技術】
近年、省エネルギーの観点から各種電気機器の効率向上が求められている。電機機器の鉄芯として使用される電磁鋼板についても、鉄損低減要求が強い。従って、最近ではより鉄損の少ない電磁鋼板が使用される場合が増加している。一方、小型電機機器に対しては小型化、メンテナンスフリー化の要求も強く、トランスを金型にセットして溶融した有機樹脂を流し込み、一体成型するいわゆるモールドトランスが実用化されている。
モーターについては騒音や振動を抑制する効果も期待できることから特にモーターのステーターをモールドする場合が増加している。
【０００３】
また、自動車用電装品についても二酸化炭素削減要求から各種効率向上の取組みが為されており、その中の一つとして内燃機関の点火装置の高圧電流発生部をプラグ近傍に設置する、いわゆるダイレクトイグニッションがある。従来、イグニッションはエンジンシャフトに付随して設置された発電機を利用し、高圧電流発生装置で電流を昇圧した後、各プラグまで高圧電流を通電していたが、ダイレクトイグニッションでは高圧電流発生部をプラグ直前に設置することにより、高圧電流の通電距離を短くして省エネルギー化を図るものである。
【０００４】
そこで、高圧電流発生部は従来のものと比較して極めて小型であることが要求される一方、電圧変換、即ちトランスとしての磁気特性も従来と同等の機能が要求されることから、その鉄芯材料としては磁気特性に優れた方向性電磁鋼板が最適である。また、高圧電流発生部は瞬間的に発生させる高電圧に応じて強力な磁力線が発生することから磁気シールドが必要であるが、磁気シールドについても透磁率の高い方向性電磁鋼板が最適である。
【０００５】
そこで、従来は無方向性電磁鋼板がシールドとして使用されていたが、現在ではダイレクトイグニッションのコアでは方向性電磁鋼板が良く使用されており、開放磁路型のいわゆるペンシルタイプでは、シールドと中心電極の間に樹脂を流し込んでモールドし一体化されている。
【０００６】
モールドされたモーターやモールドトランス、ダイレクトイグニッションいずれの電機機器においても、鉄芯やシールドを樹脂モールドすることにより成形加工されている。
【０００７】
【発明が解決しようとする課題】
ところが樹脂モールドした場合には、モールドする有機樹脂が電磁鋼板に圧縮応力を付与していると推定され、電磁鋼板に張力を付与すると磁性向上効果が見られるのと反対に、鋼板に圧縮応力を付与した場合には、磁性が劣化することが知られている。
通常、樹脂モールドする場合、電磁鋼板を所定の形状に加工した後積層して鉄芯とした後モールド金型にセットし、有機樹脂を加熱溶融して流動性を持たせてからモールド金型に圧入したり流し込んだりして一体化する。このとき、有機樹脂の硬化収縮や鋼板との熱膨張係数差により電磁鋼板に圧縮応力が付与されるという問題があった。
【０００８】
このような問題を解決する手段として、モールド樹脂と電磁鋼板の間にフィルムをはさみ込んだり、あらかじめ電磁鋼板の表面に離型剤を塗布する方法が考えられる。しかし、フィルムを挿入する場合ではモールド樹脂を圧入する際にフィルムが折れ曲がったりして電磁鋼板表面から剥れたり、フィルムと電磁鋼板の間に樹脂が入り込んだりしてモールド樹脂と電磁鋼板の分離がうまくいかないことがあり、電磁鋼板に離型剤を塗布する方法では電磁鋼板とモールド樹脂を十分分離できないと言った問題点があった。
【０００９】
本発明者らは鋭意検討した結果、あらかじめ電磁鋼板表面に特定の臨界表面張力を有する有機樹脂を塗布しておくことにより、電磁鋼板とモールド樹脂との間で分離できるだけでなく、モールド樹脂から所定以上の応力が電磁鋼板に付与された場合には、電磁鋼板と塗布された有機樹脂との間で分離されて、電磁鋼板そのものには圧縮応力が影響しないようにすることにより、電磁鋼板の特性劣化を防止する方法を開発し、本発明を完成したものである。
【００１０】
ところで、電磁鋼板の表面に無機物系被膜を形成し、その上に有機樹脂系被膜を形成する技術としては、例えば電磁鋼板の打抜き性、耐蝕性を改善するために、特公昭５３−４４８９２号公報に、酸化被膜あるいは化成被膜付き電気鉄板の表面０．１〜１０mg／dm2 の薄いポリエチレンフィルムを形成する打抜き性、耐蝕性に優れた有機被膜付き電気鉄板に関する技術が開示されている。
【００１１】
さらに、特開昭５８−１０３１０７号公報には、電磁鋼板の表面に、下塗りとして、りん酸塩系処理液を乾燥膜厚が０．３〜１．０μｍになるよう塗布し、これを焼き付けて非晶質被膜を生成した後、この上にポリエステル系、エポキシエステル系及びアクリル系樹脂の１種または２種以上の水溶性樹脂を乾燥膜厚として３〜１２μｍとなるよう塗布し、焼付け、これにより該表面に打抜き性、電気絶縁性、および耐蝕性、特に耐水性の優れた被膜を形成することを特徴とする技術が開示されている。
【００１２】
また、特開昭６２−１４４０５号公報にはフォルステライト被膜を有する方向性電磁鋼板の表面に、１００〜５００mg/m2 のアクリル系有機樹脂を主成分とした被膜を形成した２層被膜を有する切断性、すべり性、歪み取り焼鈍性のすぐれた巻き鉄芯用方向性電磁鋼板と、フォルステライト被膜上に無機系絶縁被膜を有する方向性電磁鋼板の表面に、１００〜５００mg/m2 のアクリル系有機樹脂を主成分とした被膜を形成した２層被膜を有する切断性、すべり性、歪み取り焼鈍性の優れた巻き鉄芯用方向性電磁鋼板についての技術が開示されている。
【００１３】
これら従来開発されてきた技術では、打抜き性や耐水性など電磁鋼板としての性能の向上や特性改善は十分であったものの、モールドする際にモールド樹脂との密着性もまた良好であったためにモールド樹脂と電磁鋼板の間で応力が発生し、結果として鉄芯としての磁気特性は劣化するという問題点があった。また、塗布した有機樹脂が打抜き時に発粉して金型に付着するといった問題点も有った。
【００１４】
また、特開平５−１７７７６６号公報には、家電、建材、鋼製家具、自動車などに利用されることを目的として、外面にフッ素を含む樹脂層を有し、その表面の水滴接触角を６０度未満にすることにより、耐候性、耐汚れ性に優れた樹脂被覆金属材についての技術が開示されている。
【００１５】
しかし、上記各公報ではモールドトランスのコアやダイレクトイグニッションのコアやシールドに使用された場合の磁性については何ら開示や示唆されるものはなく、また、各公報において解決される問題点である打抜き性、電気絶縁性、耐蝕性、耐水性、切断性、すべり性、歪み取り焼鈍性、耐候性、耐汚れ性とトランス鉄芯の鉄損については何ら重複するものではない。
【００１６】
【課題を解決するための手段】
即ち本発明は、以下の構成を要旨とする。
（１） 電磁鋼板の表面に、ポリエチレン、ポリプロピレン、フッ素樹脂、シリコン樹脂の１種又は２種以上よりなる有機樹脂を主成分とする臨界表面張力が２２〜３５mN/mの被膜を、厚さ０．５〜１０μｍの範囲に形成してなることを特徴とする、発粉が無く密着性に優れ、かつモールドした際に磁気特性の優れた電磁鋼板。
（２） 電磁鋼板の表面に、ポリエチレン、ポリプロピレン、フッ素樹脂、シリコン樹脂の１種又は２種以上の混合、あるいは化合物よりなる有機樹脂を主成分とする臨界表面張力が２２〜３５ mN/m の被膜を、厚さ０．５〜１０μｍの範囲に形成してなることを特徴とする、発粉が無く密着性に優れ、かつモールドした際に磁気特性の優れた電磁鋼板。
（３） フォルステライト層を有する方向性電磁鋼板の表面に、リン酸塩系絶縁被膜を形成し、さらにその表面に、請求項１或いは２に記載の有機樹脂を主成分とする臨界表面張力が２２〜３５mN/mの被膜を、厚さ０．５〜１０μｍの範囲に形成してなる、３層被膜を有することを特徴とする、発粉が無く密着性に優れ、かつモールドした際に磁気特性の優れた電磁鋼板。
【００１７】
【発明の実施の態様】
以下に本発明を詳細に説明する。
本発明は、無方向性電磁鋼板、方向性電磁鋼板に代表される一般的な電磁鋼板に適用されるが、アモルファスや電磁リロール材などへ適用してもなんら問題はない。
【００１８】
まずは、方向性電磁鋼板の適用について述べる。
一般に方向性電磁鋼板に使用される、りん酸塩系絶縁被膜としては、特公昭５３−２８３７５号公報に開示されている被膜構成が好適であり、リン酸アルミ、リン酸マグネシウム、リン酸カルシウムの１種又は２種以上から構成されるリン酸塩を主成分とし、適宜コロイド状シリカ、クロム酸塩を添加したものが使用できる。本発明では特に、りん酸塩として、りん酸アルミ、りん酸マグネシウムおよびこれらを両方使用したものにコロイド状シリカとクロム酸を添加したものが好適である。
【００１９】
このようなりん酸塩系絶縁被膜を方向性電磁鋼板の表面に形成する場合、所定の処理液を調合した後、ロールコーターなどで鋼板に塗布し、乾燥焼付するのが好適であり、使用する処理液の液組成については特に限定するものではないが、絶縁被膜の特性および塗布時の作業性から、りん酸塩：３〜２４質量％、クロム酸塩：０．２〜４．５質量％、コロイド状シリカ：４〜１６質量％、を主成分とする水溶液またはスラリーとするのがよい。また、この水溶液に被膜特性改善のために界面活性剤、ガラス化剤等を添加することは何等差し支えない。
りん酸塩系絶縁被膜の塗布量としては、０．５〜５ｇ／ｍ2 の範囲が良く、さらに最適には１〜３ｇ／ｍ2 が良好である。
【００２０】
無方向性電磁鋼板に使用される絶縁被膜としては、無機成分と有機樹脂を混合した有機無機混合被膜が一般的であり、具体的には特公昭５０−１５０１３号公報に開示されているクロム酸と２価の金属の酸化物、水酸化物、炭酸塩などと、エマルジョンタイプの有機樹脂を含有する処理液を塗布・焼き付けたいわゆるクロム酸塩系絶縁被膜などが有る。本発明では、無機成分としてはクロム酸マグネシウムを含有し、エマルジョン樹脂としてはアクリル樹脂エマルジョンを添加した処理液を１〜４μｍに塗布焼き付けたものが好適である。
【００２１】
本発明では、上記に代表される方向性電磁鋼板、無方向性電磁鋼板に対し、以下に示すような有機樹脂を施す。
本発明で使用する有機樹脂としては、ポリエチレン、ポリプロピレン、フッ素樹脂、シリコン樹脂の１種又は２種以上の混合あるいは化合物が用いられる。ポリエチレンとしては、低密度ポリエチレンでも高密度ポリエチレンでもどちらでもよい。
フッ素樹脂の具体例としては、ポリテトラフルオロエチレン、テトラフルオロエチレンパーフルオロアルキルビニルエーテル共重合体、テトラフルオロエチレンヘキサフルオロプロピレン共重合体、テトラフルオロエチレンエチレン共重合体、ポリクロロトリフルオロエチレン、ポリフッ化ビニリデン、テトラフルオロエチレンヘキサフルオロプロピレンパーフルオロアルキルビニルエーテル共重合体、クロロトリフルオロエチレンエチレン共重合体、ポリビニルフルオライドなどである。
【００２２】
以上の各有機樹脂を単独で用いても良いが、混合、あるいは変性して化合物としてから使用することにより、さらに作業性の向上などが見込まれるものである。特に、フッ素樹脂を用いる場合にはフッ素樹脂単独では濡れ性が悪く、りん酸塩系絶縁被膜やクロム酸塩系絶縁被膜上に塗布しにくい。そのような場合には、適宜界面活性剤や密着性の良好な樹脂を添加することは何ら問題ではない。また、シランカップリング剤やりん酸塩系絶縁被膜やクロム酸塩系絶縁被膜にプラズマ処理するといった密着性向上処理を施しても構わない。
【００２３】
本発明では上記有機樹脂の１種又は２種以上の混合物あるいは化合物を主成分とする有機樹脂を０．５μｍ〜１０μｍの厚みになるようコーティングする。０．５μｍ未満では本発明の効果が発現しないためであり、１０μｍ超では占積率が低下してコアの磁気特性が劣るためである。
【００２４】
本発明では、上記有機樹脂の範囲から選択されたものであっても、臨界表面張力を２２〜３５mN/mの範囲にする必要が有る。２２mN/m未満では、りん酸塩系絶縁被膜やクロム酸塩系絶縁被膜を持つ鋼板表面への塗布が事実上不可能であり、３５mN/m超ではりん酸塩系絶縁被膜やクロム酸塩系絶縁被膜との密着性、あるいはモールド樹脂との接着性が高すぎて、応力が付与される可能性があるからである。
この２２〜３５mN/mの範囲に表面張力があると、りん酸塩系被膜やクロム酸塩系絶縁被膜と本発明で使用する有機樹脂との間で剥離が発生し、電磁鋼板とモールド樹脂との間の応力が緩和される。
【００２５】
臨界表面張力は、物質の表面物性の１つで、本発明ではＪＩＳ Ｋ ６７６８に規定される方法で測定される濡れ張力の値を臨界表面張力とする。濡れ張力すなわち臨界表面張力の値が大きいほど固体表面は濡れやすい傾向を持っている。
【００２６】
本発明で使用される有機樹脂の塗布厚としては、０．５μｍ〜１０μｍの間が適当である。０．５μｍ未満では均一な塗布量コントロールが難しく、１０μｍ超では有機樹脂とりん酸塩系絶縁被膜との密着性が低下し打抜き作業時に発粉するからである。更に最適には１〜６μｍの間である。
また、曲げ加工時の潤滑性を高めるためにポリエチレンワックスなどの微粒子を有機樹脂に添加したり、酸化防止剤、レベリング剤や光沢剤といった通常のコーティング添加剤を用いても良い。
【００２７】
本発明の詳細なメカニズムは明らかではないが、モールド樹脂は一般にエポキシ樹脂やポリエステル樹脂などの密着性の非常に良好な有機樹脂が使用されており、通常のりん酸塩系絶縁被膜そのものや有機樹脂被膜ではモールド樹脂と一体化し、加熱硬化した際に電磁鋼板との間の熱膨張差から鋼板との間に応力を生じて鉄芯の磁気特性を劣化させる。
本発明では、モールド樹脂と鋼板との間に応力が生じた場合、電磁鋼板表面に被覆した有機樹脂とりん酸塩系絶縁被膜との間で剥離することにより、応力が電磁鋼板に伝播することが無く磁気特性の劣化が防止できると推定される。また、剥離が発生する面としてはモールド樹脂と電磁鋼板表面に被覆した有機樹脂被膜との間でも何ら問題無い。
【００２８】
本発明はモールドするモーターコア、モールドトランス、あるいは有機樹脂を用いてモールドするダイレクトイグニッションのコアやシールドに適用することが可能である。
【００２９】
【実施例】
脱炭焼鈍後、ＭｇＯを主成分とする焼鈍分離剤を塗布し、仕上げ焼鈍を行った０．２３mmの方向性電磁鋼板であって、その表面を水洗処理して余剰のＭｇＯを落とした後、一部のサンプルに表１に示す処理液を塗布し、８５０℃×７０秒で焼付けた。さらにその上に表２に示す有機樹脂を塗布し、表中で示す条件で乾燥させた。さらに縦６６mm、幅４０mm、積高さ１２mmのＥＩ型コアを作製し、エポキシ系樹脂にシリカフィラーを添加したモールド用樹脂を用いてモールドした。モールド時の加熱温度は１００℃で、１５０℃で後加熱を行い完全硬化させた。冷却後、１．７Ｔ、５０Ｈｚの条件でコア鉄損を測定した結果を表３に示す。
【００３０】
【表１】
【表２】
【表３】
表３における各特性を以下に説明する。
ａ) ：密着性試験として曲げ密着試験を行った。まず、圧延方向と直角方向に試験片を採取し、１５mm径の丸棒に試験片を押し付けながら１８０度折り曲げ、折り曲げ部分の被膜の剥離状況を観察し、◎，○，△，×，××の５段階評価とした。◎は全く剥離の無いもの、○は若干の剥離があるもの、△は軽度の剥離が有るもの、×は剥離の程度の激しいもの、××は全面剥離したものを示す。
ｂ) ：サンプルを幅３０mmに加工後、５００回シャーせん断して、刃に付着した粉の量を評価した。従来材とほとんどかわらないものを○、若干付着するものを△、付着量の多いものを×とした。
ｃ) ：従来材と比較して１０％以上良好なものを◎、従来材よりも５％以上良好なものを○、従来材との差が±５％未満のものを△、５％以上劣化したものを×とした。
表３からも明らかな如く、本実施例によれば、密着性、発粉性が良好でコア鉄損が向上する効果が得られている。
【００３４】
【発明の効果】
本発明により、モールドするモーター、モールドトランスのコアやダイレクトイグニッションの外筒コアに最適な密着性、発粉性を有し磁気特性の劣化を防止することが可能である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic steel sheet suitable for resin molded core products such as a molded motor, a mold transformer, and a direct ignition.
[0002]
[Prior art]
In recent years, there has been a demand for improved efficiency of various electric devices from the viewpoint of energy saving. There is a strong demand for reducing iron loss for electrical steel sheets used as iron cores for electrical equipment. Therefore, recently, the use of electrical steel sheets with less iron loss is increasing. On the other hand, there is a strong demand for miniaturization and maintenance-free for small electrical equipment, and so-called mold transformers that are integrally molded by pouring molten organic resin after setting the transformer in a mold have been put into practical use.
As for motors, the effect of suppressing noise and vibration can be expected.
[0003]
In addition, various improvements in efficiency have been made for automotive electrical components due to the demand for carbon dioxide reduction, one of which is the so-called direct ignition in which the high-voltage current generating part of the ignition device of the internal combustion engine is installed near the plug. There is. Conventionally, the ignition uses a generator attached to the engine shaft, boosts the current with a high-voltage current generator, and then supplies the high-voltage current to each plug. However, with direct ignition, a high-voltage current generator is installed. By installing it immediately before the plug, the energization distance of the high-voltage current is shortened to save energy.
[0004]
Therefore, the high-voltage current generator is required to be extremely small compared with the conventional one, while the voltage conversion, that is, the magnetic characteristics as a transformer is also required to have the same function as the conventional one. As a material, a grain-oriented electrical steel sheet having excellent magnetic properties is optimal. In addition, the magnetic field is necessary because the high-voltage current generator generates a strong magnetic field line according to the instantaneously generated high voltage, and a directional electrical steel sheet having a high magnetic permeability is optimal for the magnetic shield.
[0005]
Therefore, in the past, non-oriented electrical steel sheets were used as shields, but now, direct-oriented electrical steel sheets are often used in direct ignition cores, and the so-called pencil type of open magnetic circuit type has a shield and a center electrode. The resin is poured in between and molded and integrated.
[0006]
In any electric device such as a molded motor, a molded transformer, or a direct ignition, the iron core or shield is molded by resin molding.
[0007]
[Problems to be solved by the invention]
However, in the case of resin molding, it is presumed that the organic resin to be molded gives compressive stress to the electromagnetic steel sheet. On the contrary, when tension is applied to the electromagnetic steel sheet, the magnetic improvement effect is seen. When applied, it is known that magnetism deteriorates.
Normally, when resin molding is performed, the magnetic steel sheets are processed into a predetermined shape and then laminated to form an iron core, then set in a mold die, and the organic resin is heated and melted to have fluidity before being molded into the mold die. It is integrated by press-fitting or pouring. At this time, there was a problem that compressive stress was applied to the electromagnetic steel sheet due to curing shrinkage of the organic resin and a difference in thermal expansion coefficient from the steel sheet.
[0008]
As means for solving such a problem, a method in which a film is sandwiched between the mold resin and the electromagnetic steel sheet, or a release agent is applied to the surface of the electromagnetic steel sheet in advance is considered. However, in the case of inserting a film, when the mold resin is press-fitted, the film is bent and peeled off from the surface of the electromagnetic steel sheet, or the resin enters between the film and the electromagnetic steel sheet, so that the mold resin and the electromagnetic steel sheet are separated. In some cases, the method of applying a release agent to the electrical steel sheet cannot be sufficiently separated from the electrical steel sheet and the mold resin.
[0009]
As a result of intensive studies, the present inventors have previously applied an organic resin having a specific critical surface tension to the surface of the electromagnetic steel sheet, whereby not only separation between the electromagnetic steel sheet and the mold resin but also a predetermined amount from the mold resin is possible. When the above stress is applied to the electrical steel sheet, it is separated between the electrical steel sheet and the applied organic resin, so that compressive stress does not affect the electrical steel sheet itself. A method for preventing deterioration has been developed and the present invention has been completed.
[0010]
By the way, as a technique for forming an inorganic film on the surface of an electromagnetic steel sheet and forming an organic resin film thereon, for example, in order to improve the punchability and corrosion resistance of the electromagnetic steel sheet, Japanese Patent Publication No. 53-44892 In addition, a technique relating to an electric iron plate with an organic coating excellent in punching and corrosion resistance, which forms a thin polyethylene film having a surface of 0.1 to 10 mg / dm 2 on the surface of the electric iron plate with an oxide coating or a chemical conversion coating is disclosed.
[0011]
Furthermore, in Japanese Patent Application Laid-Open No. 58-103107, a phosphate-based treatment liquid is applied to the surface of a magnetic steel sheet as an undercoat so that the dry film thickness is 0.3 to 1.0 μm, and this is baked. After forming an amorphous film, one or more water-soluble resins of polyester, epoxy ester, and acrylic resin are applied on this to a dry film thickness of 3 to 12 μm, and baked. Discloses a technique characterized in that a film having excellent punchability, electrical insulation, and corrosion resistance, particularly water resistance, is formed on the surface.
[0012]
Japanese Patent Application Laid-Open No. 62-14405 has a two-layer film in which a film mainly composed of 100 to 500 mg / m 2 of an acrylic organic resin is formed on the surface of a grain-oriented electrical steel sheet having a forsterite film. cuttability, slip properties, and strain relief annealing of the superior wound iron core for grain-oriented electrical steel sheet, the surface of the grain-oriented electrical steel sheet having an inorganic insulating film on the forsterite coating, acrylic 100 to 500 mg / m 2 A technique for a directional electrical steel sheet for a wound iron core having a two-layer coating formed with a coating mainly composed of an organic organic resin and excellent in cutting property, slipping property, and strain relief annealing is disclosed.
[0013]
Although these technologies that have been developed in the past have sufficiently improved the performance and characteristics of the electromagnetic steel sheet, such as punchability and water resistance, they have good adhesion to the mold resin when molding. There is a problem that stress is generated between the resin and the magnetic steel sheet, and as a result, the magnetic properties as the iron core deteriorate. In addition, there is a problem that the applied organic resin is powdered at the time of punching and adheres to the mold.
[0014]
JP-A-5-177766 discloses a resin layer containing fluorine on the outer surface for the purpose of being used in home appliances, building materials, steel furniture, automobiles, and the like. A technique for a resin-coated metal material excellent in weather resistance and stain resistance by being less than 2 degrees is disclosed.
[0015]
However, in each of the above publications, there is no disclosure or suggestion of magnetism when used in a core of a mold transformer, a core of a direct ignition, or a shield, and punching is a problem solved in each publication. Electrical insulation, corrosion resistance, water resistance, severability, slipperiness, strain relief annealing, weather resistance, dirt resistance, and iron loss of transformer iron cores do not overlap at all.
[0016]
[Means for Solving the Problems]
That is, the gist of the present invention is as follows.
(1) A film having a critical surface tension of 22 to 35 mN / m mainly composed of an organic resin composed of one or more of polyethylene, polypropylene, fluororesin, and silicon resin is formed on the surface of the electrical steel sheet with a thickness of 0. An electrical steel sheet that is formed in a range of 5 to 10 μm, has no powdering, has excellent adhesion, and has excellent magnetic properties when molded.
(2) on the surface of the electrical steel sheet, polyethylene, polypropylene, fluororesin, one or more mixing of the silicone resin, or the critical surface tension mainly composed of organic resin consisting of compounds of 22 to 35 mN / m An electrical steel sheet having a coating formed in a thickness range of 0.5 to 10 μm, having no powdering, excellent adhesion, and excellent magnetic properties when molded.
( 3 ) A phosphate-based insulating coating is formed on the surface of a grain-oriented electrical steel sheet having a forsterite layer, and a critical surface tension mainly composed of the organic resin according to claim 1 or 2 is formed on the surface. It has a three-layer coating formed by forming a coating of 22 to 35 mN / m in a thickness range of 0.5 to 10 μm. It has excellent adhesion without powdering and is magnetic when molded. Electrical steel sheet with excellent characteristics.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention is described in detail below.
The present invention is applied to a general electromagnetic steel sheet represented by a non-oriented electrical steel sheet and a directional electrical steel sheet, but there is no problem even if it is applied to an amorphous or electromagnetic reroll material.
[0018]
First, the application of grain-oriented electrical steel sheets will be described.
As a phosphate-based insulating coating generally used for grain-oriented electrical steel sheets, a coating configuration disclosed in Japanese Patent Publication No. 53-28375 is suitable, and one of aluminum phosphate, magnesium phosphate, and calcium phosphate is used. Or the thing which has as a main component the phosphate comprised from 2 or more types, and added the colloidal silica and chromate suitably can be used. In the present invention, as the phosphate, those obtained by adding colloidal silica and chromic acid to aluminum phosphate, magnesium phosphate, and those using both are preferable.
[0019]
When such a phosphate-based insulating coating is formed on the surface of a grain-oriented electrical steel sheet, it is preferable to prepare and apply a predetermined treatment liquid to the steel sheet with a roll coater and dry baking. Although it does not specifically limit about the liquid composition of a processing liquid, From the characteristic of an insulating film and workability | operativity at the time of application | coating, phosphate: 3-24 mass%, chromate: 0.2-4.5 mass% , Colloidal silica: It is good to make it the aqueous solution or slurry which has 4-16 mass% as a main component. In addition, there is no problem in adding a surfactant, a vitrifying agent and the like to the aqueous solution for improving the film properties.
The coating amount of phosphate-based insulating coatings, often in the range of 0.5 to 5 g / m 2, and more optimally good 1 to 3 g / m 2.
[0020]
As an insulating coating used for non-oriented electrical steel sheets, an organic-inorganic mixed coating obtained by mixing an inorganic component and an organic resin is generally used. Specifically, chromic acid disclosed in Japanese Patent Publication No. 50-15013 is disclosed. And divalent metal oxides, hydroxides, carbonates, and so-called chromate-based insulating coatings obtained by applying and baking a treatment solution containing an emulsion type organic resin. In the present invention, it is preferable that the inorganic component contains magnesium chromate and the emulsion resin is applied and baked to a thickness of 1 to 4 μm with an acrylic resin emulsion added.
[0021]
In this invention, the organic resin as shown below is given with respect to the grain-oriented electrical steel plate represented by the above, and a non-oriented electrical steel plate.
As the organic resin used in the present invention, one or a mixture of two or more of polyethylene, polypropylene, fluororesin, and silicon resin or a compound is used. The polyethylene may be either low density polyethylene or high density polyethylene.
Specific examples of the fluororesin include polytetrafluoroethylene, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene hexafluoropropylene copolymer, tetrafluoroethylene ethylene copolymer, polychlorotrifluoroethylene, polyfluoride. Examples thereof include vinylidene, tetrafluoroethylene hexafluoropropylene perfluoroalkyl vinyl ether copolymer, chlorotrifluoroethylene ethylene copolymer, and polyvinyl fluoride.
[0022]
Each of the above organic resins may be used alone. However, use of the compound after mixing or modifying it as a compound is expected to further improve workability. In particular, when a fluororesin is used, the fluororesin alone has poor wettability and is difficult to apply on a phosphate insulating film or a chromate insulating film. In such a case, it is not a problem to add a surfactant or a resin having good adhesion as appropriate. Moreover, you may perform the adhesive improvement process of plasma-processing to a silane coupling agent, a phosphate-type insulating film, or a chromate-type insulating film.
[0023]
In the present invention, an organic resin mainly composed of one or a mixture of two or more of the above organic resins or a compound is coated to have a thickness of 0.5 μm to 10 μm. If the thickness is less than 0.5 μm, the effect of the present invention is not exhibited, and if it exceeds 10 μm, the space factor decreases and the magnetic properties of the core are inferior.
[0024]
In the present invention, the critical surface tension needs to be in the range of 22 to 35 mN / m even if selected from the range of the organic resin. If it is less than 22 mN / m, it is practically impossible to apply it to the surface of a steel plate having a phosphate insulating film or chromate insulating film, and if it exceeds 35 mN / m, a phosphate insulating film or chromate based coating is not possible. This is because the adhesiveness to the insulating coating or the adhesiveness to the mold resin is too high and stress may be applied.
If there is a surface tension in the range of 22 to 35 mN / m, peeling occurs between the phosphate-based coating or chromate-based insulating coating and the organic resin used in the present invention. The stress during is relaxed.
[0025]
The critical surface tension is one of the surface physical properties of a substance. In the present invention, the critical surface tension is defined as the value of the wetting tension measured by the method defined in JIS K 6768. The larger the value of the wetting tension, that is, the critical surface tension, the more the solid surface tends to get wet.
[0026]
The coating thickness of the organic resin used in the present invention is suitably between 0.5 μm and 10 μm. If the thickness is less than 0.5 μm, it is difficult to control the uniform coating amount, and if it exceeds 10 μm, the adhesion between the organic resin and the phosphate insulating coating is reduced, and powdering occurs during the punching operation. More preferably, it is between 1 and 6 μm.
Further, in order to improve lubricity during bending, fine particles such as polyethylene wax may be added to the organic resin, or ordinary coating additives such as antioxidants, leveling agents and brighteners may be used.
[0027]
Although the detailed mechanism of the present invention is not clear, an organic resin having a very good adhesion such as an epoxy resin or a polyester resin is generally used as the mold resin, and a normal phosphate insulating coating itself or an organic resin is used. The coating is integrated with the mold resin, and when heated and cured, stress is generated between the steel sheet and the magnetic steel sheet due to the difference in thermal expansion between the magnetic steel sheet and the magnetic properties of the iron core.
In the present invention, when stress occurs between the mold resin and the steel sheet, the stress propagates to the electrical steel sheet by peeling between the organic resin coated on the surface of the electrical steel sheet and the phosphate insulating coating. It is estimated that the deterioration of magnetic characteristics can be prevented. Further, there is no problem between the mold resin and the organic resin film coated on the surface of the magnetic steel sheet as the surface where peeling occurs.
[0028]
The present invention can be applied to a motor core to be molded, a mold transformer, or a direct ignition core or shield to be molded using an organic resin.
[0029]
【Example】
After decarburization annealing, a 0.23 mm directional electrical steel sheet coated with an annealing separator mainly composed of MgO and subjected to final annealing, and after the surface was washed with water to remove excess MgO, A treatment liquid shown in Table 1 was applied to some samples and baked at 850 ° C. for 70 seconds. Further, an organic resin shown in Table 2 was applied thereon and dried under the conditions shown in the table. Further, an EI type core having a length of 66 mm, a width of 40 mm, and a stacking height of 12 mm was produced and molded using a molding resin in which a silica filler was added to an epoxy resin. The heating temperature at the time of molding was 100 ° C., and post-heating was performed at 150 ° C. for complete curing. Table 3 shows the results of measuring the core iron loss under the conditions of 1.7 T and 50 Hz after cooling.
[0030]
[Table 1]
[Table 2]
[Table 3]
Each characteristic in Table 3 will be described below.
a): A bending adhesion test was performed as an adhesion test. First, specimens were taken in a direction perpendicular to the rolling direction, bent 180 degrees while pressing the specimen against a 15 mm-diameter round bar, and the state of peeling of the coating at the bent portion was observed. ◎, ○, △, ×, XX It was set as 5 grade evaluation. ◎ indicates that there is no peeling, ○ indicates that there is slight peeling, Δ indicates that there is slight peeling, × indicates that the degree of peeling is severe, and xx indicates that the entire surface is peeled off.
b): After processing the sample to a width of 30 mm, shear shearing was performed 500 times, and the amount of powder adhering to the blade was evaluated. A material that hardly changed from the conventional material was marked with ◯, a material that adhered slightly was marked with Δ, and a material with a large amount of adhesion was marked with ×.
c): 10% or more better than the conventional material ◎, better than the conventional material 5% or better ○, difference from the conventional material less than ± 5% △ 5% or more deteriorated What was done was made into x.
As is clear from Table 3, according to this example, the adhesion and powdering properties are good and the core iron loss is improved.
[0034]
【The invention's effect】
According to the present invention, it is possible to prevent the deterioration of magnetic properties by having optimum adhesiveness and powdering property for a motor to be molded, a core of a mold transformer, and an outer cylinder core of a direct ignition.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000356662A JP4081230B2 (en) | 2000-11-22 | 2000-11-22 | Electrical steel sheet with excellent magnetic properties suitable for mold cores |
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|---|---|---|---|
| JP2000356662A JP4081230B2 (en) | 2000-11-22 | 2000-11-22 | Electrical steel sheet with excellent magnetic properties suitable for mold cores |
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| JP2002164207A JP2002164207A (en) | 2002-06-07 |
| JP4081230B2 true JP4081230B2 (en) | 2008-04-23 |
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| JP2005317683A (en) * | 2004-04-27 | 2005-11-10 | Nippon Steel Corp | Grain-oriented electromagnetic steel plate for three-phase laminated iron core |
| CN103025917B (en) | 2010-07-23 | 2014-12-31 | 新日铁住金株式会社 | Electromagnetic steel sheet and process for production thereof |
| EP4317486A1 (en) * | 2021-03-31 | 2024-02-07 | Nippon Steel Corporation | Non-oriented electromagnetic steel sheet and method for manufacturing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS5483618A (en) * | 1977-12-16 | 1979-07-03 | Kawasaki Steel Co | Low grade electromagnetic steel plate with excellent space factor * punching property and weldability |
| JPS61183479A (en) * | 1985-02-09 | 1986-08-16 | Nippon Steel Corp | Surface treatment of electrical steel sheet |
| JPS61183480A (en) * | 1985-02-09 | 1986-08-16 | Sumitomo Metal Ind Ltd | Formation of insulating film on electrical steel sheet |
| JPS6214405A (en) * | 1985-07-12 | 1987-01-23 | Nippon Steel Corp | Directional electromagnetic steel plate for wound core having superior cutting property |
| JPS62227093A (en) * | 1986-03-28 | 1987-10-06 | Sumitomo Metal Ind Ltd | Electrical steel sheet having excellent blankability and insulation resistance characteristic |
| JP2662338B2 (en) * | 1992-03-17 | 1997-10-08 | 川崎製鉄株式会社 | Electromagnetic steel sheet for laminated iron core with excellent punchability and weldability |
| JPH062161A (en) * | 1992-06-15 | 1994-01-11 | Nkk Corp | Galvanized steel sheet excellent in formability, external appearance characteristic after forming, and corrosion resistance |
| JPH0681162A (en) * | 1992-09-02 | 1994-03-22 | Sumitomo Metal Ind Ltd | Formation of insulated film excellent in insulation property and punching property and coating solution |
| US5605964A (en) * | 1995-06-22 | 1997-02-25 | Minnesota Mining And Manufacturing Company | Acrylate-containing polymer blends and methods of using |
| JP2000208346A (en) * | 1999-01-13 | 2000-07-28 | Toyota Motor Corp | Ignition coil for internal combustion engine and manufacture of the same |
| JP2000228322A (en) * | 1999-02-08 | 2000-08-15 | Hitachi Ltd | Ignition coil for internal combustion engine |
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