JP4134775B2 - Baking method of coating film by high frequency induction heating - Google Patents
Baking method of coating film by high frequency induction heating Download PDFInfo
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- JP4134775B2 JP4134775B2 JP2003077923A JP2003077923A JP4134775B2 JP 4134775 B2 JP4134775 B2 JP 4134775B2 JP 2003077923 A JP2003077923 A JP 2003077923A JP 2003077923 A JP2003077923 A JP 2003077923A JP 4134775 B2 JP4134775 B2 JP 4134775B2
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- 239000011248 coating agent Substances 0.000 title claims description 53
- 238000000576 coating method Methods 0.000 title claims description 53
- 238000010438 heat treatment Methods 0.000 title claims description 42
- 230000006698 induction Effects 0.000 title claims description 32
- 238000000034 method Methods 0.000 title claims description 17
- 239000011347 resin Substances 0.000 claims description 35
- 229920005989 resin Polymers 0.000 claims description 35
- 239000003973 paint Substances 0.000 claims description 15
- 239000002245 particle Substances 0.000 claims description 13
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 239000000839 emulsion Substances 0.000 claims description 6
- 239000006185 dispersion Substances 0.000 claims description 3
- 239000000843 powder Substances 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 239000000725 suspension Substances 0.000 claims description 2
- 229910000831 Steel Inorganic materials 0.000 description 19
- 239000010959 steel Substances 0.000 description 19
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 6
- 238000004080 punching Methods 0.000 description 6
- 229920000178 Acrylic resin Polymers 0.000 description 5
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- 229910052782 aluminium Inorganic materials 0.000 description 4
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- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 2
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- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
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- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 239000004640 Melamine resin Substances 0.000 description 1
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- 238000009413 insulation Methods 0.000 description 1
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- GIOZLVMCHDGNNZ-UHFFFAOYSA-N magnesium;oxido-(oxido(dioxo)chromio)oxy-dioxochromium Chemical compound [Mg+2].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O GIOZLVMCHDGNNZ-UHFFFAOYSA-N 0.000 description 1
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Images
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- General Induction Heating (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Description
【０００１】
【発明の属する技術分野】
この発明は、高周波誘導加熱による塗膜の焼付け方法に関し、特に従来、高周波誘導加熱のみでの塗装焼付けの際に懸念された被膜欠陥の有利な改善を、打抜性の改善と共に達成しようとするものである。
【０００２】
【従来の技術】
電磁鋼板の表面には、絶縁性をはじめとして、打抜性や耐食性、耐熱性などの諸特性を付与するために、絶縁被膜が被覆される。
従来、かような絶縁被膜の被覆に際しては、熱風炉を用いたガス加熱方式が採用されていたが、最近では、生産能率の向上の観点から、高周波誘導加熱方式が用いられるようになってきた。
しかしながら、上記した高周波誘導加熱方式では、加熱に際して塗装面の内部から加熱されることから、塗料表面の硬化が不十分となり、耐傷つき性や耐汚染性などの被膜特性の劣化を余儀なくされた。また、未蒸発の溶剤に起因してワキと呼ばれる、表面に無数の細かい穴が残る状態が発生し、被膜外観の劣化を招く場合もあった。
【０００３】
上記の問題を解決するものとして、高周波誘導加熱方式と熱風吹き付け方式の両者を併用する方法が提案された（例えば特許文献１）。
【０００４】
【特許文献１】
特開平３−284375号公報（特許請求の範囲）
【０００５】
【発明が解決しようとする課題】
しかしながら、上記した高周波誘導加熱と熱風吹き付けの両者を併用する方法では、設備費が嵩むだけでなく、加熱処理が煩雑になり、さらに高周波誘導加熱のみの場合に比べると処理時間が長いという問題があった。
【０００６】
【課題を解決するための手段】
この発明は、上記の問題を有利に解決するもので、高周波誘導加熱方式のみによって、前述したような被膜特性や被膜外観の劣化を招くことなしに、塗膜を短時間で焼き付けることができ、また打抜性の向上にも有用な高周波誘導加熱による塗膜の焼付け方法を提案することを目的とする。
【０００７】
さて、発明者らは、上記の課題を達成すべく、高周波誘導加熱に際し、その加熱条件を種々に変化させる広範囲な実験を行い、各場合における被膜特性および被膜外観、さらには打抜性について調査した。
その結果、
(1) 処理温度（到達板温）を従来よりも低めに設定した上で、適用周波数および昇温速度を的確に制御してやれば、高周波誘導加熱方式のみによっても、被膜特性や被膜外観の劣化を招くことなしに塗膜を効果的に焼付けできる、
(2) また、塗布される水系塗料中の樹脂の形態を調整することにより、高周波誘導加熱での焼付けと相まって打抜性が格段に向上する
ことを新たに見出した。
この発明は、上記の知見に立脚するものである。
【０００８】
すなわち、この発明は、金属板の表面に、樹脂と無機成分を含有する水系塗料を塗布したのち、高周波誘導加熱により塗膜を焼き付けるに際し、水系塗料中の全樹脂量の50mass％以上を、粒径が30nm以上のエマルション樹脂、ディスパージョン樹脂、サスペンション樹脂および粉末樹脂のうちから選んだ少なくともいずれか一種とし、到達板温が 100〜250 ℃の温度域において、誘導加熱周波数：50kHz 以上、昇温速度：50℃/s以上の条件で焼き付けることを特徴とする高周波誘導加熱による塗膜の焼付け方法である。
【０００９】
【発明の実施の形態】
以下、この発明を具体的に説明する。
まず、この発明の基礎となった実験結果について説明する。
図１に、高周波誘導加熱を用いた塗膜の焼付けに際し、到達板温、昇温速度および誘導加熱周波数を種々に変化させた場合における被膜外観および被膜特性について調査した結果を示す。なお、被膜外観としてはワキ等の塗装むらの発生の有無を、また被膜特性としては耐傷つき性の良否について調べた。
同図に示したとおり、到達板温を 100〜250 ℃と低めに設定した上で、鋼板の昇温速度：50℃/s以上、誘導加熱周波数：50 kHz以上の条件で塗膜の焼付けを行えば、ワキ等の塗装むらの発生は全くなく、かつ耐傷つき性の劣化もないことが究明されたのである。
【００１０】
なお、この発明において鋼板の昇温速度の上限は特に制限されることはないが、本発明は誘導加熱のみで加熱されるので、鋼板側（塗膜下層）から加熱されることになり、粉末樹脂やエマルション樹脂、ディスパージョン樹脂のように完全溶解ではなく、粒子の形態をもっている樹脂が表層近傍に濃縮されるので、最表層樹脂量が多くなって打抜性が向上する。しかしながら、昇温速度があまりに大きいとこの打抜性の向上効果が不十分となるので、昇温速度の上限は 200℃/s程度とすることが好ましい。
同様に、誘導加熱周波数についてもその上限は特に制限されることはないが、この誘導加熱周波数があまりに大きいと、インバーターの容量が増大し、設備コストが大きくなるので、誘導加熱周波数の上限は 200 kHz程度とすることが好ましい。
【００１１】
さらに、打抜性の向上には、後述する実施例からも明らかなように、上記した粒子の形態をもっている樹脂の粒径が30nm以上であることが必要である。というのは、粒径が30nm未満の粒子では十分な打抜性の改善効果が得られないからである。
また、粒径が30nm以上の樹脂が全樹脂量の50mass％以上とすることも重要である。というのは、粒径が30nm以上の樹脂量が全樹脂量の50mass％を下回ると、やはり十分な打抜性の改善効果が得られないからである。
上記のような樹脂形態にすること、および誘導加熱によって鋼板側から加熱することによって、粒子の形態をもった樹脂が効果的に表層近傍に濃縮し、打抜性の一層の向上が達成されるのである。
【００１２】
この発明における好適塗料としては、次のようなものが挙げられる。
(1) 電磁鋼板用のクロム含有半有機系絶縁被膜
・クロム酸塩水溶液：５〜2000重量部（CrO3換算）
・水性樹脂：100 重量部（樹脂固形分）
・還元剤：５〜100 重量部
・アルミニウム化合物：５〜1000重量部（アルミニウム換算）
ここに
クロム酸塩水溶液：無水クロム酸、クロム酸塩、重クロム酸塩のうちから選んだ少なくとも一種を主剤に用いた水溶液。
水性樹脂：内層としては、フェノール樹脂、エポキシ樹脂、ウレタン樹脂、アミノ樹脂、ポリアミド樹脂など。外層としては、アクリル酸、メタクリル酸、クロトン酸、イタコン酸、マレイン酸、フマール酸などのエチレン性不飽和カルボン酸と、これに重合可能な（メタ）アクリル酸メチル、（メタ）アクリル酸エチル等のアクリル酸またはメタクリル酸のアルキルエステルなどのエチレン性不飽和単量体から形成される樹脂。
還元剤：エチレングリコール、ショ糖、グリセリン等の多価有機アルコール類、ぎ酸、酢酸等のカルボン酸など。
アルミニウム化合物：アルミニウムの酸化物、水酸化物、炭酸塩、クロム酸塩など。
【００１３】
(2) 電磁鋼板用のクロムレス半有機系絶縁被膜
無機成分および水性樹脂、その他必要に応じて防錆剤等の添加剤を、水性塗液中の固形分濃度が10〜30質量％の範囲で含有させたもの。
ここに
無機成分：シリカ、アルミナ、酸化チタン、酸化アンチモンなど。
水性樹脂：アクリル樹脂、アルキド樹脂、ポリオレフィン樹脂、スチレン樹脂、酢酸ビニル樹脂、エポキシ樹脂、フェノール樹脂、ウレタン樹脂、メラミン樹脂など。
【００１４】
次に、この発明の実施に用いて好適な塗料焼付け設備について説明する。
図２に、上記した塗料焼付け設備の好適例を模式で示し、図中番号１は連続焼鈍炉、２は塗液塗装装置、３は塗料焼付け装置、そして４は鋼板冷却装置である。
冷間圧延後の鋼板を、連続焼鈍炉１で所望の焼鈍処理を施したのち、塗液塗装装置２にて鋼板の表面に、所定の成分に調整された水系の絶縁塗液を塗布し、ついで塗料焼付け装置３において．この発明に従う焼付け処理を施す。すなわち、鋼板の到達板温を 100〜250 ℃と低めに設定した上で、鋼板の昇温速度：50℃/s以上、誘導加熱周波数：50 kHz以上の条件で塗料の焼付け処理を行う。その後、鋼板冷却装置４を通して鋼板を室温まで冷却する。
【００１５】
【実施例】
実施例１
常法に従い製造した無方向性電磁鋼板の表面に、焼付け条件を種々に変化させて半有機系の絶縁被膜を被成した。
なお、半有機系絶縁被膜用の塗料は、次のとおりである。
・アクリル樹脂エマルション（粒径：100 nm）：100 重量部（樹脂固形分）
・重クロム酸マグネシウム： 200 重量部（CrO3換算）
・エチレングリコール：120 重量部
・水酸化アルミニウム：20重量部（アルミニウム換算）
【００１６】
得られた絶縁被膜付き無方向性電磁鋼板におけるワキ発生の有無、耐傷つき性および打抜性について調べた結果を、表１に示す。
なお、ワキ発生の有無は目視により判断した。
また、打抜性は、下記の条件で打ち抜いた時、初期かえり高さが10μm になるように金型を調整して連続打抜性試験を行い、かえり高さが50μm に達するまでの打抜き回数で評価した。
・15mmφスチール鋼ダイス使用
・クリアランス：５％
・打抜油：使用
さらに、耐傷つき性は、フェルトに荷重を付加した状態で被膜表面を往復させ、目視により被膜のキズの程度を判定した。試験条件は、フェルト接触面積：10×10mm、荷重：0.9 kg、20往復とした。評価基準は次のとおりである。
◎：ほとんどキズが認められない
○：擦り跡が判別できる程度
△：地鉄が若干露出
×：剥離し、地鉄が露出
【００１７】
【表１】
同表から明らかなように、本発明の要件を満足する発明例はいずれも、ワキの発生はなく、また耐傷つき性に優れ、さらには打抜性も良好であった。
【００１９】
実施例２
実施例１と同様の方法で製造した無方向性電磁鋼板の表面に、高周波誘導加熱方式で半有機系の絶縁被膜を被成した。誘導加熱の条件は、到達板温：200 ℃、到達板温までの昇温速度：80℃/s、誘導加熱周波数：70 kHzとした。
ここで、半有機系絶縁被膜用の塗料としては、表２に示すように
・アクリル酸樹脂（水溶性）
・アクリル樹脂エマルション
の混合比率およびアクリル樹脂エマルションの粒径を種々に変化させた以外は、実施例１と同様の組成とした。
得られた絶縁被膜付き無方向性電磁鋼板におけるワキ発生の有無、耐傷つき性および打抜性について調べた結果を、表２併記する。
【００２０】
【表２】
同表から明らかなように、本発明に従い、水系塗料中における粒子形態の樹脂の粒径および比率を適正に調整することによって、打抜性が格段に向上することが分かる。
【００２２】
以上、主に電磁鋼板の表面に絶縁被膜を被成する場合について説明したが、この発明は、上記の場合だけに限るものではなく、家電製品等に使用される塗装鋼板を製造する場合にも同様に適用できることはいうまでもない。
【００２３】
【発明の効果】
かくして、この発明によれば、鋼板の表面に塗膜を焼き付けるに際し、高周波誘導加熱方式のみによって、被膜特性や被膜外観の劣化を招くことなしに短時間で焼き付けることができ、さらには打抜性も格段に向上させることができる。
【図面の簡単な説明】
【図１】 被膜特性および被膜外観に及ぼす到達板温、昇温速度および誘導加熱周波数の影響を示した図である。
【図２】 この発明の実施に用いて好適な塗料焼付け設備の模式図である。
【符号の説明】
１ 連続焼鈍炉
２ 塗液塗装装置
３ 塗料焼付け装置
４ 鋼板冷却装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of baking a coating film by high-frequency induction heating, and in particular, attempts to achieve an advantageous improvement of a coating defect, which has been a concern in the past by only high-frequency induction heating, together with improvement of punchability. Is.
[0002]
[Prior art]
The surface of the electrical steel sheet is coated with an insulating coating in order to impart various properties such as punchability, corrosion resistance, and heat resistance as well as insulation.
Conventionally, a gas heating method using a hot stove has been employed for coating such an insulating film, but recently, from the viewpoint of improving production efficiency, a high frequency induction heating method has been used. .
However, in the above-described high-frequency induction heating method, heating is performed from the inside of the painted surface, so that the coating surface is not sufficiently cured, and coating properties such as scratch resistance and contamination resistance are inevitably deteriorated. Moreover, the state where countless fine holes remain on the surface, which is called “waki”, is caused by the non-evaporated solvent, and the appearance of the film may be deteriorated.
[0003]
In order to solve the above problem, a method of using both the high frequency induction heating method and the hot air blowing method has been proposed (for example, Patent Document 1).
[0004]
[Patent Document 1]
JP-A-3-284375 (Claims)
[0005]
[Problems to be solved by the invention]
However, the above-described method using both high-frequency induction heating and hot air blowing not only increases the equipment cost but also makes the heat treatment complicated, and further, there is a problem that the processing time is longer than in the case of only high-frequency induction heating. there were.
[0006]
[Means for Solving the Problems]
The present invention advantageously solves the above-mentioned problem, and only by high-frequency induction heating method, the coating film can be baked in a short time without causing deterioration of the coating properties and coating appearance as described above, Moreover, it aims at proposing the baking method of the coating film by the high frequency induction heating useful also for punching improvement.
[0007]
Now, in order to achieve the above-mentioned problems, the inventors conducted a wide range of experiments in which the heating conditions were variously changed during high-frequency induction heating, and investigated the coating properties and coating appearance in each case, as well as the punchability. did.
as a result,
(1) If the treatment temperature (final plate temperature) is set lower than before and the applied frequency and heating rate are accurately controlled, the coating characteristics and coating appearance can be degraded only by the high-frequency induction heating method. Can effectively bake the coating without inviting,
(2) Further, it has been newly found that the punching property is remarkably improved by adjusting the form of the resin in the applied water-based paint in combination with baking by high-frequency induction heating.
The present invention is based on the above findings.
[0008]
That is, in the present invention, after applying a water-based paint containing a resin and an inorganic component to the surface of a metal plate, when baking the coating film by high-frequency induction heating, 50 mass% or more of the total resin amount in the water-based paint is reduced. At least one selected from emulsion resin, dispersion resin, suspension resin, and powder resin with a diameter of 30 nm or more, induction heating frequency: 50 kHz or more in the temperature range where the ultimate plate temperature is 100 to 250 ° C Speed: A coating film baking method by high-frequency induction heating characterized by baking under conditions of 50 ° C./s or higher.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be specifically described below.
First, the experimental results on which the present invention is based will be described.
FIG. 1 shows the results of investigating the coating appearance and coating characteristics when the ultimate plate temperature, the heating rate and the induction heating frequency are variously changed during baking of the coating using high frequency induction heating. The appearance of the coating was checked for the presence or absence of uneven coating, such as a crack, and the coating characteristics were checked for good scratch resistance.
As shown in the figure, the final plate temperature was set to a low value of 100-250 ° C, and the coating film was baked under the conditions of the steel plate heating rate: 50 ° C / s or more and the induction heating frequency: 50 kHz or more. It has been found that if this is done, there will be no occurrence of uneven coating such as armpits, and there will be no deterioration in scratch resistance.
[0010]
In this invention, the upper limit of the heating rate of the steel sheet is not particularly limited, but since the present invention is heated only by induction heating, it is heated from the steel sheet side (coating layer lower layer) and powder. Since the resin having the form of particles is not completely dissolved like a resin, emulsion resin, or dispersion resin, but is concentrated in the vicinity of the surface layer, the amount of the outermost layer resin is increased and the punchability is improved. However, since the effect of improving the punchability becomes insufficient if the temperature rising rate is too large, the upper limit of the temperature rising rate is preferably about 200 ° C./s.
Similarly, the upper limit of the induction heating frequency is not particularly limited. However, if the induction heating frequency is too large, the capacity of the inverter increases and the equipment cost increases. It is preferably about kHz.
[0011]
Further, in order to improve the punchability, it is necessary that the particle diameter of the resin having the above-described particle form is 30 nm or more, as will be apparent from Examples described later. This is because sufficient improvement in punchability cannot be obtained with particles having a particle size of less than 30 nm.
It is also important that the resin having a particle size of 30 nm or more is 50 mass% or more of the total resin amount. This is because if the amount of resin having a particle size of 30 nm or more is less than 50 mass% of the total amount of resin, a sufficient punching improvement effect cannot be obtained.
By making the resin form as described above and heating from the steel sheet side by induction heating, the resin having the form of particles is effectively concentrated in the vicinity of the surface layer, and further improvement of punchability is achieved. It is.
[0012]
Preferred examples of the paint in the present invention include the following.
(1) Chromium-containing semi-organic insulating coating for electrical steel sheets / chromate aqueous solution: 5 to 2000 parts by weight (CrO 3 equivalent)
・ Aqueous resin: 100 parts by weight (resin solids)
・ Reducing agent: 5 to 100 parts by weight ・ Aluminum compound: 5 to 1000 parts by weight (in terms of aluminum)
Here, chromate aqueous solution: an aqueous solution using at least one selected from chromic anhydride, chromate, and dichromate as a main ingredient.
Aqueous resin: As the inner layer, phenol resin, epoxy resin, urethane resin, amino resin, polyamide resin, etc. As the outer layer, ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid and fumaric acid, and methyl (meth) acrylate and ethyl (meth) acrylate that can be polymerized therewith A resin formed from an ethylenically unsaturated monomer such as an alkyl ester of acrylic acid or methacrylic acid.
Reducing agent: polyhydric organic alcohols such as ethylene glycol, sucrose and glycerin, carboxylic acids such as formic acid and acetic acid.
Aluminum compound: Aluminum oxide, hydroxide, carbonate, chromate, etc.
[0013]
(2) Chromeless semi-organic insulating coating for electrical steel sheets Inorganic components and water-based resins, and other additives such as rust preventives as necessary, with a solid content concentration in the aqueous coating liquid of 10 to 30% by mass Contained.
Here inorganic components: silica, alumina, titanium oxide, antimony oxide and the like.
Aqueous resin: acrylic resin, alkyd resin, polyolefin resin, styrene resin, vinyl acetate resin, epoxy resin, phenol resin, urethane resin, melamine resin, etc.
[0014]
Next, a paint baking facility suitable for use in the practice of the present invention will be described.
FIG. 2 schematically shows a preferred example of the above-described paint baking equipment, in which reference numeral 1 is a continuous annealing furnace, 2 is a coating liquid coating apparatus, 3 is a paint baking apparatus, and 4 is a steel plate cooling apparatus.
After the cold-rolled steel sheet is subjected to a desired annealing treatment in the continuous annealing furnace 1, a water-based insulating coating liquid adjusted to a predetermined component is applied to the surface of the steel sheet by the coating
[0015]
【Example】
Example 1
A semi-organic insulating coating was formed on the surface of a non-oriented electrical steel sheet produced according to a conventional method by changing the baking conditions in various ways.
The paint for the semi-organic insulating coating is as follows.
・ Acrylic resin emulsion (particle size: 100 nm): 100 parts by weight (resin solids)
・ Magnesium dichromate: 200 parts by weight (CrO 3 equivalent)
・ Ethylene glycol: 120 parts by weight ・ Aluminum hydroxide: 20 parts by weight (in terms of aluminum)
[0016]
Table 1 shows the results of examining the presence / absence of cracking, scratch resistance, and punchability in the obtained non-oriented electrical steel sheet with an insulating coating.
In addition, the presence or absence of the occurrence of armpits was judged visually.
In addition, when punching under the following conditions, the die is adjusted so that the initial burr height is 10μm, and a continuous punching test is performed. The number of punches until the burr height reaches 50μm. It was evaluated with.
・ Uses 15mmφ steel steel dies ・ Clearance: 5%
-Punching oil: Use Further, for scratch resistance, the surface of the coating was reciprocated with a load applied to the felt, and the degree of scratching of the coating was visually determined. Test conditions were felt contact area: 10 × 10 mm, load: 0.9 kg, 20 reciprocations. The evaluation criteria are as follows.
◎: Scratches are hardly recognized ○: Degree of rubbing can be discriminated △: The steel is slightly exposed x: The steel is peeled off and the steel is exposed
[Table 1]
As is clear from the table, all of the inventive examples that satisfy the requirements of the present invention were free of cracks, excellent in scratch resistance, and also had good punchability.
[0019]
Example 2
A semi-organic insulating coating was formed on the surface of the non-oriented electrical steel sheet produced by the same method as in Example 1 by high frequency induction heating. The conditions for induction heating were as follows: ultimate plate temperature: 200 ° C., rate of temperature rise to ultimate plate temperature: 80 ° C./s, induction heating frequency: 70 kHz.
Here, as shown in Table 2, acrylic resin (water-soluble) is used as the coating material for the semi-organic insulating coating.
-It was set as the composition similar to Example 1 except having changed the mixing ratio of the acrylic resin emulsion, and the particle size of the acrylic resin emulsion variously.
The results of investigating the presence / absence of cracking, scratch resistance and punchability in the obtained non-oriented electrical steel sheet with an insulating coating are shown in Table 2.
[0020]
[Table 2]
As is clear from the table, it can be seen that the punchability is remarkably improved by appropriately adjusting the particle size and ratio of the resin in the form of particles in the water-based paint according to the present invention.
[0022]
As mentioned above, although the case where an insulating coating was mainly formed on the surface of an electromagnetic steel sheet was explained, this invention is not restricted only to the above-mentioned case, also when manufacturing the coated steel sheet used for household appliances etc. Needless to say, the same applies.
[0023]
【The invention's effect】
Thus, according to the present invention, when the coating film is baked on the surface of the steel sheet, it can be baked in a short time without causing deterioration of the coating properties and coating appearance only by the high-frequency induction heating method. Can also be improved significantly.
[Brief description of the drawings]
FIG. 1 is a graph showing the effects of ultimate plate temperature, heating rate, and induction heating frequency on coating properties and coating appearance.
FIG. 2 is a schematic view of a paint baking facility suitable for use in the practice of the present invention.
[Explanation of symbols]
1
Claims (1)
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| JP2003077923A JP4134775B2 (en) | 2003-03-20 | 2003-03-20 | Baking method of coating film by high frequency induction heating |
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Cited By (1)
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| JPH09267721A (en) * | 1996-04-01 | 1997-10-14 | Masakatsu Ito | Wiper |
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| JP4954589B2 (en) * | 2006-04-10 | 2012-06-20 | 新日本製鐵株式会社 | Method for producing surface-treated steel sheet and heat drying apparatus |
| JP4954758B2 (en) * | 2007-03-19 | 2012-06-20 | 新日本製鐵株式会社 | Method for producing plated steel sheet with excellent corrosion resistance and paint adhesion |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4680871A (en) * | 1985-05-17 | 1987-07-21 | David Reznik | Apparatus and method for drying and curing coated substrates |
| JPS62100561A (en) * | 1985-10-28 | 1987-05-11 | Nisshin Steel Co Ltd | Insulating film-forming composition for electromagnetic steel plate and formation of insulating film on said steel plate |
| US5456953A (en) * | 1993-02-26 | 1995-10-10 | Armco Steel Company, L.P. | Method for coating bake hardenable steel with a water based chromium bearing organic resin |
| JPH08290111A (en) * | 1995-04-24 | 1996-11-05 | Nippon Steel Corp | Manufacturing method of painted metal sheet |
| JPH09108623A (en) * | 1995-10-18 | 1997-04-28 | Nippon Steel Corp | Electrical insulating film treatment method for electrical steel sheet |
| JP3174504B2 (en) * | 1996-04-01 | 2001-06-11 | 新日本製鐵株式会社 | Method for producing surface-treated steel sheet with excellent press workability |
| JPH1015485A (en) * | 1996-06-28 | 1998-01-20 | Kawasaki Steel Corp | Silicon steel sheet having insulating coating film capable of stress relief annealing, excellent in corrosion resistance and containing no chromium compound and formation of coating film thereof |
| JP3370235B2 (en) * | 1996-07-30 | 2003-01-27 | 川崎製鉄株式会社 | Method of forming an insulating coating excellent in corrosion resistance and free of chromium compound capable of strain relief annealing on the surface of an electrical steel sheet |
| JP2001049456A (en) * | 1999-08-11 | 2001-02-20 | Nkk Corp | Production of chromate treated steel sheet excellent in adhesion with organic film |
| JP3554531B2 (en) * | 2000-09-01 | 2004-08-18 | 新日本製鐵株式会社 | Electrical steel sheet with extremely excellent coating properties and method for forming its insulating coating |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPH09267721A (en) * | 1996-04-01 | 1997-10-14 | Masakatsu Ito | Wiper |
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