JP2004204244A

JP2004204244A - Post-treatment liquid for plated steel sheet, post-treated plated steel sheet with the use of it, and manufacturing method therefor

Info

Publication number: JP2004204244A
Application number: JP2002370952A
Authority: JP
Inventors: Takahiro Hayashida; 貴裕林田; Tatsuya Oshima; 達也大嶋; Hiroyuki Yamane; 博之山根; Masao Komai; 正雄駒井
Original assignee: Toyo Kohan Co Ltd
Current assignee: Toyo Kohan Co Ltd
Priority date: 2002-12-20
Filing date: 2002-12-20
Publication date: 2004-07-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide such a post-treatment liquid for a post-treated plated steel sheet as to form a film which has a superior wettability with a solder even when a chlorine-free flux is used, particularly does not make the wettability with the solder deteriorate even after the elapse of time, and besides, superior corrosion resistance, to provide a post-treated plated steel sheet made by coating the treatment liquid onto a plated steel sheet and drying it, and to provide a manufacturing method therefor. <P>SOLUTION: The post treatment liquid for the plated steel sheet comprises 100-800 g/L of a water-based acrylic resin, 10-100 g/L of a rust-preventive agent, 50-600 g/L of a water-solubilized rosin and 0.5-100 g/L of an oxidation inhibitor; or 100-900 g/L of a water-based urethane resin, 10-100 g/L of a rust-preventive agent and 0.5-100 g/L of an oxidation inhibitor. The post-treated plated steel sheet is made by coating the above liquid onto a plated steel sheet so as to make a dried film thickness to be 0.05-10 μm. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明はめっき鋼板、特に半田めっき鋼板の後処理に係わり、半田の濡れ性、経時性、耐食性を向上させるめっき鋼板用後処理液、それを用いた後処理めっき鋼板、およびその製造方法に関する。
【０００２】
【従来の技術】
一般に半田付けの可能な錫めっき鋼板、鉛−錫めっき鋼板、銅めっき鋼板、亜鉛めっき鋼板などのめっき鋼板は、使用される環境にさらされた際にめっきの外観が変化して酸化皮膜が成長し、場合によっては赤錆が発生することがある。そのため、これらのめっき鋼板においては経時した際の酸化膜の成長による半田性の低下を抑制する後処理方法が求められている。また、最近の電子部品の分野においては、基板となるめっき鋼板などの耐食性の劣化を防止するため、塩素を含有する腐食性の強い活性なフラックスの使用が拒否される傾向にあり、塩素を含有しないフラックスを用いた場合においても半田の濡れ性に優れる材料が求められている。塩素を含まない弱活性または非活性のフラックスを使用した場合は、半田はめっき鋼板に付着するものの、めっき鋼板上を均一に濡らすまでに長時間を要し、半田の濡れ性に劣り、その傾向はめっき鋼板の経時の増大にともなって顕著となる。
【０００３】
鋼板上に錫めっきを施し、次いで錫めっき上に亜鉛、ニッケル、コバルトのいずれか１種以上を主成分とするめっき、または亜鉛、ニッケル、コバルトのいずれか１種以上に錫、鉄、鉛、銅のいずれか１種以上を含有してなる、錫の標準電極電位より卑な電位を示す合金めっきを施した、半田用二層めっき鋼板を開示している（例えば、特許文献１参照）。このめっき鋼板はクロメート処理皮膜のような耐食性に優れた保護皮膜層を有していないため、耐食性が十分ではなく、腐食生成物の皮膜が生成することにより、半田濡れ性も劣化するおそれがある。
【０００４】
また、鋼板上にＳｎ−Ｚｎ合金層、または表面にＮｉめっきまたはＦｅ−Ｎｉ拡散層のいずれかからなる表面処理層を形成させた表面処理鋼板上にＳｎ−Ｚｎ合金層を形成させ、これらのＳｎ−Ｚｎ合金層上にリン酸マグネシウムを主体とする無機皮膜を形成させてなる環境対応型電子部品用表面処理鋼板を開示している（例えば、特許文献２参照）。このリン酸マグネシウムを主体とする無機皮膜もＳｎ−Ｚｎ合金に対して高耐食性を付与することはできるが、その安定さ故に、特に塩素を含まない弱活性または非活性のフラックスを使用した場合の半田性に乏しい欠点を有している。
【０００５】
本出願に関する先行技術文献情報として次のものがある。
【特許文献１】
特開昭６３−２７７７８６号公報
【特許文献２】
特開２００２−２４９８８５号公報
【０００６】
【発明が解決しようとする課題】
本発明は、めっき鋼板を半田付けする際に、塩素を含有しないフラックスを使用した場合においても、半田の濡れ性に優れ、特に経時しても半田の濡れ性が劣化せず、しかも耐食性に優れた皮膜が得られるめっき鋼板用後処理液、およびこのめっき鋼板用後処理液をめっき鋼板に塗布し乾燥してなる後処理めっき鋼板およびその製造方法を提供するものである。
【０００７】
【課題を解決するための手段】
上記課題を解決する本発明のめっき鋼板用後処理液は、水系アクリル樹脂を１００〜８００ｇ／Ｌ、防錆剤を１０〜１００ｇ／Ｌ、水溶化ロジンを５０〜６００ｇ／Ｌ、酸化防止剤を０．５〜１００ｇ／Ｌ含有してなることを特徴とするもの、または
水系ウレタン樹脂を１００〜９００ｇ／Ｌ、防錆剤を１０〜１００ｇ／Ｌ、酸化防止剤を０．５〜１００ｇ／Ｌ含有してなることを特徴とするものである。
前記防錆剤は、アミン塩を含んだ化合物、あるいはスチレン・無水マレイン酸共重合体のどちらか一方もしくは両方を含んでいることが望ましい。
前記酸化防止剤は、フェノール系酸化防止剤および／またはリン系酸化防止剤であることが好ましい。
また、本発明の後処理めっき鋼板は、上記何れかのめっき鋼板用後処理液を、めっき鋼板に乾燥後の厚みが０．０５〜１０μｍとなるように塗布してなることを特徴とし、また
前記めっき鋼板が鋼板上に亜鉛めっき層、錫めっき層、亜鉛−錫合金めっき層、銅めっき層、ニッケルめっき層のいずれかのめっき層を形成させてなるめっき鋼板であることを特徴とするものである。
さらに、本発明の後処理めっき鋼板の製造方法は、上記何れかのめっき鋼板用後処理液を、めっき鋼板に乾燥後の厚みが０．０５〜１０μｍとなるように塗布し乾燥することを特徴とする。
【０００８】
【発明の実施の形態】
本発明に係るめっき鋼板用後処理液は、水系アクリル樹脂を１００〜８００ｇ／Ｌ、防錆剤を１０〜１００ｇ／Ｌ、水溶化ロジンを５０〜６００ｇ／Ｌ、酸化防止剤を０．５〜１００ｇ／Ｌ含有する水系アクリル樹脂を主成分とするめっは鋼板用後処理液、または水系ウレタン樹脂を１００〜９００ｇ／Ｌ、防錆剤を１０〜１００ｇ／Ｌ、酸化防止剤を０．５〜１００ｇ／Ｌを含有する水系ウレタン樹脂を主成分とするめっき鋼板用後処理液であり、本発明に係る後処理めっき鋼板およびその製造方法は、このめっき鋼板用後処理液を、鋼板上に亜鉛めっき層、錫めっき層、亜鉛−錫合金めっき層、銅めっき層、ニッケルめっき層のいずれかのめっき層を形成させためっき鋼板に、乾燥厚みが０．０５〜１０μｍになるように塗布し乾燥処理することによって、後処理めっき鋼板とするものである。この後処理めっき鋼板は、無塩素系フラックスを使用しても半田性に優れ、経時しても、あるいは加熱しても半田の濡れ性が劣化せず、また耐食性および耐酸化性にも優れる。
【０００９】
以下、実施形態にて本発明を詳細に説明する。
本発明の水系アクリル樹脂を主成分とするめっき鋼板用後処理液において、水系アクリル樹脂は、カルボン酸を有するアクリル系モノマーの重合体または共重合体であり、特に水溶液重合、エマルジョン重合などの重合法を限定するものではない。しかし、水系アクリル樹脂の酸価（樹脂１ｇ中に含まれる遊離脂肪酸を中和するのに要する水酸化カリウムのミリグラム数）は、１５０以下であることが好ましい。濃度として、１００〜８００ｇ／Ｌの範囲が好ましい。１００ｇ／Ｌ未満では半田性向上の効果がなく、耐食性も低下する。一方，８００ｇ／Ｌを越えると半田性向上の効果が飽和し、水溶化ロジンと混ぜ合わせた場合に粘度が高くなり、ゲル化する恐れがあり、好ましくない。
【００１０】
水溶性ロジンは５０〜６００ｇ／Ｌの範囲で添加する必要がある。水溶化ロジンは、ロジンの主成分であるアビエチン酸分子内のカルボン酸基をアミン塩などにより中和し、ロジン石鹸とする方法により得られる。５０ｇ／Ｌ未満では経時後の半田濡れ性が不十分であり、６００ｇ／Ｌを越えると高粘度となり、ゲル化しやすく、塗布が困難になるので、好ましくない。
【００１１】
防錆剤は、クロムを含まないものを添加するのが良い。クロムを含まない以外は特に限定されないが、アミンを含んだ化合物、あるいはスチレン・無水マレイン酸共重合体のどちらか一方もしくは両方を含んだものを適用できる。アミンを含んだ化合物としては、具体的には、有機アミン石けんの単独あるいは混合したものを使用する。有機アミン石けんにはドデシルアミン、オレオイルイミダゾリン、アミノプロピル牛脂アミン、ロジンアミンが含まれ、アミンはカルボン酸などと造塩して使用することが出来る。スチレン・無水マレイン酸共重合体としては、スチレン・無水マレイン酸共重合アルキルエステル・アンモニウム塩が好ましい。添加量としては１０〜１００ｇ／ｌであることが好ましい。１０ｇ／ｌ未満では、耐食性向上に効果が認められず、１００ｇ／ｌを越えると耐食性向上効果は極めて良好であるが、液の粘度が上昇して塗布が困難になるので好ましくない。
【００１２】
本発明において、めっき鋼板用の後処理液に酸化防止剤を添加することにより、樹脂層の酸化および変質を抑制するとともに、めっき層の酸化も抑制し、経時した場合においても優れた半田濡れ性を確保することが可能である。この用途に適用する酸化防止剤としては、硫黄系酸化防止剤などもあるが、フェノール系酸化防止剤またはリン系酸化防止剤が好ましく、両者を併用してもよい。添加量としては０．５〜１００ｇ／ｌであることが好ましい。０．５ｇ／ｌ未満では、耐酸化性向上に効果が認められず、１００ｇ／ｌを超えると液の粘度が上昇して塗布が困難になるので好ましくない。
【００１３】
一方、本発明の水系ウレタン樹脂を主成分とするめっき鋼板用後処理液において、水系ウレタン樹脂は特に限定されるものではないが、高強度を有する方が耐食性に効果がある。濃度として、１００〜９００ｇ／Ｌの範囲が好ましい。１００ｇ／Ｌ未満では耐食性が不十分であり、９００ｇ／Ｌを超えると半田濡れ性が悪くなる。また、防錆剤は、水系アクリル樹脂を主成分とするめっき鋼板用後処理液の場合と同様に、クロムを含まない以外は特に限定されないが、アミンを含んだ化合物も適用できる。具体的には、有機アミン石けんの単独あるいは混合したものを使用する。有機アミン石けんにはドデシルアミン、オレオイルイミダゾリン、アミノプロピル牛脂アミン、ロジンアミンが含まれ、アミンはカルボン酸などと造塩して使用することが出来る。スチレン・無水マレイン酸共重合体としては、スチレン・無水マレイン酸共重合アルキルエステル・アンモニウム塩が好ましい。添加量は１０〜１００ｇ／ｌであることが好ましく、１０ｇ／ｌ未満では、耐食性向上に効果が認められず、１００ｇ／ｌを越えると耐食性向上効果は極めて良好であるが、液の粘度が上昇して塗布が困難になるので好ましくない。
【００１４】
また、酸化防止剤についても、水系アクリル樹脂を主成分とするめっき鋼板用後処理液の場合と同様に、フェノール系酸化防止剤またはリン系酸化防止剤が好ましく、両者を併用してもよい。添加量についても水系アクリル樹脂を主成分とするめっき鋼板用後処理液の場合と同様の理由から、０．５〜１００ｇ／ｌであることが好ましい。
【００１５】
上記各めっき鋼板用後処理液のｐＨは３〜１０の範囲が適当である。ｐＨが３未満の場合は処理液の安定性が不良であり、１０を越えても好ましくない。より長期間処理液が安定して使用するには、ｐＨ６〜９の範囲が好ましい。
【００１６】
上記のようにして得られた何れかのめっき鋼板用後処理液を、めっき鋼板の片面あるいは両面に塗布する。この場合、表裏面で塗布膜厚を変えても良い。塗布する方法としては、浸漬法、ロールコート法、カーテンフローコート法、スプレーコート法など、公知の方法で良く、特に限定されるものではない。しかし、両面塗布を行う場合、本処理液が水系であることを活かして、連続めっきラインの後工程において、浸漬・絞りによる塗布やロールコートなどを行う方法が容易で経済的である。
【００１７】
めっき鋼板用後処理液は、乾燥後の膜厚が０．０５〜１０μｍとなるように塗布する。めっき鋼板用後処理液を塗布しためっき鋼板は、後処理皮膜を成膜させるために乾燥する。皮膜の厚みが０．０５μｍ未満では、十分な半田性、耐指紋性が得られないばかりでなく、耐食性が著しく劣る。１０μｍを越えると特性向上の効果が飽和し、コストメリットがなくなる。
【００１８】
めっき鋼板の仕様は特に限定されるものではない。溶融めっき、または電気めっきなど、いずれの手法を用いても十分な効果を有するめっきが得られる。また、銅めっき、ニッケルめっき、錫めっき、鉛−錫合金めっき、亜鉛めっき、亜鉛−ニッケル、亜鉛−アルミニウム、亜鉛−錫、亜鉛−鉄あるいは亜鉛−コバルトなどの亜鉛合金めっき、亜鉛−コバルト−モリブデン等からなる複合亜鉛めっき、または下層の錫と上層の亜鉛や、下層の亜鉛と上層の錫からなる二層めっきなどの複層めっきなど、鋼板上に施すめっきの種類も用途に応じて選択される。
【００１９】
【実施例】
焼鈍および調質圧延を施した鋼板（板厚０．５ｍｍ）をめっき原板として、アルカリ脱脂、および硫酸酸洗による清浄化処理を行った後、表１に示す金属または合金を、表１に示すめっき法を用いて表１に示すめっき量でめっきし、めっき番号Ａ〜Ｋで示すめっき鋼板を作製した。これらのめっき鋼板の中から表２に示すめっき番号のめっき鋼板の両面に、浸漬・絞り法、スプレーコート法あるいはロールコート法により表２に示す試料作成条件でめっき鋼板用後処理液を塗布した後、９０℃の温度で乾燥し、試料番号１〜９の試料を作製した。比較例として、後処理を施さないめっきままのめっき鋼板を試料番号１０の試料とした。このようにして得られた試料番号１〜１０の試料について、下記の特性評価を行い、表３にその評価結果を示した。
【００２０】
また、めっき番号Ａ〜Ｋで示すめっき鋼板の中から表４に示すめっき番号のめっき鋼板の両面に、浸漬・絞り法、スプレーコート法あるいはロールコート法により表４に示す試料作成条件でめっき鋼板用後処理液を塗布した後、９０℃の温度で乾燥し、試料番号１１〜１９の試料を作製した。比較例として、後処理を施さないめっきままのめっき鋼板を試料番号２０の試料とした。このようにして得られた試料番号１１〜２０の試料について、下記の特性評価を行い、表５にその評価結果を示した。
【００２１】
[特性評価]
１）半田濡れ性：
メニスコグラフ法（ＭＩＬ−ＳＴＤ−８８３Ｂ）により、ＳＯＬＤＥＲＣＨＥＣＫＥＲ（ＭＯＤＥＬＳＡＴ−５０００、ＲＨＥＳＣＡ製）を使用し、上記の供試材から切り出した幅１０ｍｍのサンプルを、実施例１の場合は塩素を含まない非活性フラックス（ＮＡ−２００、タムラ化研製）に浸漬し、実施例２の場合は塩素を含まない弱活性フラックス（ラピックスＲＭＡ、日本半田工業製）に浸漬し、その後２５０℃に保持した半田浴（ＪＩＳＺ３２８２：Ｈ６０Ａ）に前記のフラックスを塗布したサンプルを浸漬速度２ｍｍ／秒で、２ｍｍ浸漬させ、半田が濡れるまでの時間ゼロクロスタイムを測定し、下記に示す基準で半田濡れ性を評価した。濡れ時間は短い程半田付け性に優れることを示す。なお、試験は試料作製直後と恒温恒湿（６０℃、９５％ＲＨ）で５００時間経時後の二通りで行った。×以外を合格範囲とした。
◎：３秒未満、○：３〜５秒未満、△：５〜１０秒未満、×：１０秒以上
２）耐食性：
ＪＩＳＺ２３７１に準じて塩水噴霧試験を４８時間行い、赤錆の発生程度を肉眼観察し、下記に示す基準で耐食性を評価した。×以外を合格範囲とした。
○：赤錆の発生なし、△：一部赤錆発生、×：全面に赤錆発生
【００２２】
その結果、表３及び表５に示すように、本発明の後処理めっき鋼板は何れも、半田濡れ性、特に経時後の半田濡れ性、および耐食性の項目において良好な性状を示し、本発明の酸化防止剤の効果が発揮された。一方、比較例のように、後処理液を施さないめっき鋼板においては、半田濡れ性、および耐食性の両方において性能が劣っていた。
【００２３】
【表１】

【００２４】
【表２】

【００２５】
【表３】

【００２６】
【表４】

【００２７】
【表５】

【００２８】
【発明の効果】
以上のように、本発明によれば、めっき鋼板を半田付けする際に、塩素を含有しないフラックスを使用した場合においても、半田の濡れ性に優れ、特に半田の濡れ性が経時しても劣化しない耐酸化性に優れ、しかも耐食性に優れた皮膜が得られるめっき鋼板用後処理液、およびこのめっき鋼板用後処理液をめっき鋼板に塗布し乾燥してなる後処理めっき鋼板およびその製造方法を提供することが可能となった。本発明のめっき鋼板用後処理液を塗布した後処理めっき鋼板は、塩素を含まない非活性フラックスを使用した場合においても、半田の濡れ性に優れ、半田の濡れ性は経時しても劣ることがなく、また耐食性にも優れている。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a post-treatment of a plated steel sheet, particularly a solder-plated steel sheet, and relates to a post-treatment liquid for a plated steel sheet that improves solder wettability, aging, and corrosion resistance, a post-treated plated steel sheet using the same, and a method of manufacturing the same.
[0002]
[Prior art]
Generally, plated steel sheets such as tin-plated steel sheets, lead-tin-plated steel sheets, copper-plated steel sheets, and galvanized steel sheets that can be soldered change the appearance of plating when exposed to the environment in which they are used and grow oxide films. In some cases, red rust may occur. Therefore, in these plated steel sheets, there is a demand for a post-treatment method that suppresses a decrease in solderability due to the growth of an oxide film over time. In the field of recent electronic components, the use of highly corrosive, active fluxes containing chlorine tends to be refused in order to prevent the corrosion resistance of plated steel sheets, etc., used as substrates. There is a demand for a material that is excellent in solder wettability even when a non-flux is used. When a weakly active or non-active flux containing no chlorine is used, the solder adheres to the plated steel sheet, but it takes a long time to uniformly wet the plated steel sheet, and the solder wettability is poor. Is remarkable with the aging of the plated steel sheet.
[0003]
Tin plating on a steel sheet, then zinc, nickel, plating containing at least one of zinc, nickel, and cobalt on tin plating, or tin, iron, lead, Patent Document 1 discloses a two-layer plated steel sheet for solder, which contains one or more types of copper and is plated with an alloy exhibiting a potential lower than the standard electrode potential of tin. This plated steel sheet does not have a protective film layer having excellent corrosion resistance such as a chromate-treated film, so that the corrosion resistance is not sufficient, and the formation of a corrosion product film may deteriorate solder wettability. .
[0004]
Further, an Sn—Zn alloy layer is formed on a surface-treated steel sheet having a Sn—Zn alloy layer formed on a steel sheet, or a surface treatment layer formed of either Ni plating or an Fe—Ni diffusion layer formed on the surface thereof. It discloses an environment-friendly surface-treated steel sheet for electronic components in which an inorganic film mainly composed of magnesium phosphate is formed on a Sn—Zn alloy layer (for example, see Patent Document 2). The inorganic coating mainly composed of magnesium phosphate can also impart high corrosion resistance to the Sn-Zn alloy, but because of its stability, particularly when a weakly active or inactive flux containing no chlorine is used. It has a disadvantage of poor solderability.
[0005]
Prior art document information on the present application includes the following.
[Patent Document 1]
JP-A-63-277786 [Patent Document 2]
JP-A-2002-249885 [0006]
[Problems to be solved by the invention]
The present invention is excellent in solder wettability even when a flux containing no chlorine is used when soldering a plated steel sheet, in particular, does not deteriorate the solder wettability even with the lapse of time, and is excellent in corrosion resistance It is intended to provide a post-treatment liquid for a plated steel sheet which can provide a coated film, a post-treated plated steel sheet obtained by applying and drying the post-treatment liquid for a plated steel sheet to a plated steel sheet, and a method for producing the same.
[0007]
[Means for Solving the Problems]
The post-treatment liquid for a plated steel sheet of the present invention that solves the above-mentioned problems includes a water-based acrylic resin of 100 to 800 g / L, a rust preventive of 10 to 100 g / L, a water-soluble rosin of 50 to 600 g / L, and an antioxidant. 0.5 to 100 g / L, an aqueous urethane resin of 100 to 900 g / L, a rust inhibitor of 10 to 100 g / L, and an antioxidant of 0.5 to 100 g / L. It is characterized by containing.
It is preferable that the rust inhibitor contains one or both of a compound containing an amine salt and a styrene / maleic anhydride copolymer.
The antioxidant is preferably a phenolic antioxidant and / or a phosphorus antioxidant.
Further, the post-treated plated steel sheet of the present invention is characterized in that any one of the above-described post-treatment liquids for a plated steel sheet is applied to a plated steel sheet so that the thickness after drying is 0.05 to 10 μm, The plated steel sheet is a plated steel sheet obtained by forming any one of a zinc plating layer, a tin plating layer, a zinc-tin alloy plating layer, a copper plating layer, and a nickel plating layer on a steel sheet. It is.
Further, the method for producing a post-treated plated steel sheet of the present invention is characterized in that any one of the above-mentioned post-treatment liquids for a plated steel sheet is applied to the plated steel sheet so that the thickness after drying is 0.05 to 10 μm, and dried. And
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The post-treatment liquid for a plated steel sheet according to the present invention comprises 100 to 800 g / L of an aqueous acrylic resin, 10 to 100 g / L of a rust preventive, 50 to 600 g / L of water-soluble rosin, and 0.5 to 0.5 g of an antioxidant. 100 g / L of aqueous acrylic resin as main component, post-treatment liquid for steel plate, or 100 to 900 g / L of aqueous urethane resin, 10 to 100 g / L of rust inhibitor, 0.5 to 0.5 g of antioxidant A post-treatment liquid for a plated steel sheet mainly containing an aqueous urethane resin containing 100 g / L. The post-treated plated steel sheet according to the present invention and the method for producing the same are characterized in that the post-treatment liquid for a plated steel sheet is coated with zinc on the steel sheet. Coating on a plated steel sheet on which one of a plating layer, a tin plating layer, a zinc-tin alloy plating layer, a copper plating layer, and a nickel plating layer is formed, so that the dry thickness is 0.05 to 10 μm, and then drying. processing By Rukoto, it is an aftertreatment plated steel sheet. This post-processed plated steel sheet has excellent solderability even when a chlorine-free flux is used, does not deteriorate the solder wettability with time or heating, and also has excellent corrosion resistance and oxidation resistance.
[0009]
Hereinafter, the present invention will be described in detail with embodiments.
In the post-treatment solution for a plated steel sheet mainly containing an aqueous acrylic resin of the present invention, the aqueous acrylic resin is a polymer or a copolymer of an acrylic monomer having a carboxylic acid, and particularly a polymer such as aqueous solution polymerization and emulsion polymerization. It does not limit legality. However, the acid value of the water-based acrylic resin (the number of milligrams of potassium hydroxide required to neutralize the free fatty acid contained in 1 g of the resin) is preferably 150 or less. The concentration is preferably in the range of 100 to 800 g / L. If it is less than 100 g / L, there is no effect of improving the solderability, and the corrosion resistance is reduced. On the other hand, if it exceeds 800 g / L, the effect of improving the solderability is saturated, and when mixed with water-soluble rosin, the viscosity becomes high, which may cause gelation, which is not preferable.
[0010]
It is necessary to add the water-soluble rosin in the range of 50 to 600 g / L. The water-soluble rosin can be obtained by a method in which a carboxylic acid group in abietic acid molecule, which is a main component of rosin, is neutralized with an amine salt or the like to obtain a rosin soap. If it is less than 50 g / L, the solder wettability after aging is insufficient, and if it exceeds 600 g / L, it becomes undesirably high in viscosity, easily gelled, and difficult to apply.
[0011]
It is preferable to add a rust preventive that does not contain chromium. There is no particular limitation except that it does not contain chromium, but a compound containing either one or both of a compound containing an amine and a styrene / maleic anhydride copolymer can be applied. As the compound containing an amine, specifically, an organic amine soap alone or as a mixture is used. Organic amine soaps include dodecylamine, oleoylimidazoline, aminopropyl tallowamine, and rosinamine, and amines can be used after forming a salt with a carboxylic acid or the like. The styrene / maleic anhydride copolymer is preferably a styrene / maleic anhydride copolymerized alkyl ester / ammonium salt. The addition amount is preferably from 10 to 100 g / l. When the amount is less than 10 g / l, no effect on improving the corrosion resistance is recognized. When the amount exceeds 100 g / l, the effect on improving the corrosion resistance is extremely good, but it is not preferable because the viscosity of the liquid increases and coating becomes difficult.
[0012]
In the present invention, by adding an antioxidant to a post-treatment solution for a plated steel sheet, the oxidation and deterioration of the resin layer are suppressed, and the oxidation of the plating layer is also suppressed. It is possible to secure. Antioxidants applicable to this use include sulfur-based antioxidants, but phenol-based antioxidants or phosphorus-based antioxidants are preferred, and both may be used in combination. The addition amount is preferably 0.5 to 100 g / l. If the amount is less than 0.5 g / l, no effect on improving the oxidation resistance is recognized, and if it exceeds 100 g / l, the viscosity of the liquid increases and coating becomes difficult.
[0013]
On the other hand, in the post-treatment liquid for a plated steel sheet containing the aqueous urethane resin as a main component of the present invention, the aqueous urethane resin is not particularly limited, but the higher the strength, the more effective the corrosion resistance. The concentration is preferably in the range of 100 to 900 g / L. If it is less than 100 g / L, the corrosion resistance is insufficient, and if it exceeds 900 g / L, the solder wettability deteriorates. Further, the rust preventive is not particularly limited as in the case of the post-treatment liquid for plated steel sheet mainly containing water-based acrylic resin, except that it does not contain chromium, but a compound containing amine can also be applied. Specifically, an organic amine soap alone or as a mixture is used. Organic amine soaps include dodecylamine, oleoylimidazoline, aminopropyl tallowamine, and rosinamine, and amines can be used after forming a salt with a carboxylic acid or the like. The styrene / maleic anhydride copolymer is preferably a styrene / maleic anhydride copolymerized alkyl ester / ammonium salt. The addition amount is preferably from 10 to 100 g / l, and if it is less than 10 g / l, the effect of improving the corrosion resistance is not recognized. If it exceeds 100 g / l, the effect of improving the corrosion resistance is extremely good, but the viscosity of the liquid increases. It is not preferable because the application becomes difficult.
[0014]
Also, as for the antioxidant, a phenolic antioxidant or a phosphorus-based antioxidant is preferable, as in the case of the post-treatment liquid for a plated steel sheet containing a water-based acrylic resin as a main component, and both may be used in combination. The amount of addition is also preferably 0.5 to 100 g / l for the same reason as in the case of the post-treatment liquid for plated steel sheets mainly containing an aqueous acrylic resin.
[0015]
The pH of each of the above-mentioned post-treatment liquids for plated steel sheets is suitably in the range of 3 to 10. If the pH is less than 3, the stability of the processing solution is poor, and if it exceeds 10, it is not preferable. In order to use the treatment liquid stably for a longer period, the pH is preferably in the range of 6 to 9.
[0016]
The post-treatment liquid for any of the plated steel sheets obtained as described above is applied to one or both surfaces of the plated steel sheet. In this case, the coating thickness may be changed on the front and back surfaces. The method of applying may be a known method such as a dipping method, a roll coating method, a curtain flow coating method, and a spray coating method, and is not particularly limited. However, in the case of performing double-sided coating, it is easy and economical to perform application by immersion and squeezing or roll coating in the subsequent process of the continuous plating line, taking advantage of the fact that the treatment liquid is aqueous.
[0017]
The post-treatment liquid for a plated steel sheet is applied so that the film thickness after drying is 0.05 to 10 μm. The plated steel sheet to which the post-treatment liquid for a plated steel sheet has been applied is dried to form a post-treatment film. When the thickness of the film is less than 0.05 μm, not only sufficient solderability and fingerprint resistance cannot be obtained, but also corrosion resistance is extremely poor. If it exceeds 10 μm, the effect of improving the characteristics is saturated, and the cost merit is lost.
[0018]
The specifications of the plated steel sheet are not particularly limited. Either technique such as hot-dip plating or electroplating can be used to obtain a plating having a sufficient effect. In addition, copper plating, nickel plating, tin plating, lead-tin alloy plating, zinc plating, zinc alloy plating such as zinc-nickel, zinc-aluminum, zinc-tin, zinc-iron or zinc-cobalt, zinc-cobalt-molybdenum Depending on the application, the type of plating to be applied to the steel sheet is also selected according to the application, such as composite zinc plating consisting of etc., or multi-layer plating such as tin of the lower layer and zinc of the upper layer, or double layer plating of the lower layer of zinc and the upper layer of tin. You.
[0019]
【Example】
After using a steel sheet (plate thickness 0.5 mm) subjected to annealing and temper rolling as a plating base sheet and performing a cleaning treatment by alkali degreasing and sulfuric acid pickling, the metals or alloys shown in Table 1 are shown in Table 1. Plating was performed using a plating method at a plating amount shown in Table 1, and plated steel sheets indicated by plating numbers A to K were produced. From among these plated steel sheets, a post-treatment solution for plated steel sheets was applied to both sides of a plated steel sheet having a plating number shown in Table 2 by a dipping / drawing method, a spray coat method or a roll coat method under the sample preparation conditions shown in Table 2. Thereafter, the sample was dried at a temperature of 90 ° C. to prepare samples of sample numbers 1 to 9. As a comparative example, a plated steel sheet that had not been subjected to post-treatment was used as a sample of Sample No. 10. The characteristics of the samples Nos. 1 to 10 obtained as described above were evaluated as follows, and Table 3 shows the evaluation results.
[0020]
In addition, from among the plated steel sheets indicated by plating numbers A to K, both sides of the plated steel sheets having the plating numbers shown in Table 4 were coated by the dipping / drawing method, the spray coating method or the roll coating method under the sample preparation conditions shown in Table 4. After applying the post-treatment liquid for use, the sample was dried at a temperature of 90 ° C. to prepare Samples Nos. 11 to 19. As a comparative example, a plated steel sheet that had not been subjected to post-treatment and was as-plated was used as sample No. 20. The characteristics of the samples Nos. 11 to 20 obtained as described above were evaluated as follows, and Table 5 shows the evaluation results.
[0021]
[Characteristic evaluation]
1) Solder wettability:
According to the meniscograph method (MIL-STD-883B), using a SOLDERCHECKER (MODEL SAT-5000, manufactured by RESCA), a 10 mm wide sample cut out of the above test material was used. Immersed in an active flux (NA-200, manufactured by Tamura Kaken), and in the case of Example 2, immersed in a weakly active flux containing no chlorine (Lapics RMA, manufactured by Nippon Handa Kogyo), and then a solder bath (250 ° C.) A sample obtained by applying the above flux to JIS Z 3282: H60A) was immersed at 2 mm at a immersion speed of 2 mm / sec, and the time until the solder was wet was measured. The zero cross time was measured, and the solder wettability was evaluated based on the following criteria. The shorter the wetting time, the better the solderability. The test was performed in two ways: immediately after sample preparation and after 500 hours of aging at constant temperature and constant humidity (60 ° C., 95% RH). A value other than x was regarded as a pass range.
◎: less than 3 seconds, ：: less than 3 to 5 seconds, Δ: less than 5 to 10 seconds, ×: 10 seconds or more 2) Corrosion resistance:
A salt spray test was performed for 48 hours in accordance with JIS Z 2371, and the occurrence of red rust was visually observed, and the corrosion resistance was evaluated according to the following criteria. A value other than x was regarded as a pass range.
：: no red rust was generated, Δ: red rust was partially generated, ×: red rust was generated on the entire surface.
As a result, as shown in Tables 3 and 5, each of the post-treated plated steel sheets of the present invention exhibited good properties in terms of solder wettability, particularly, solder wettability after aging, and corrosion resistance. The effect of the antioxidant was exhibited. On the other hand, in the case of a plated steel sheet not subjected to the post-treatment liquid as in the comparative example, the performance was poor in both solder wettability and corrosion resistance.
[0023]
[Table 1]

[0024]
[Table 2]

[0025]
[Table 3]

[0026]
[Table 4]

[0027]
[Table 5]

[0028]
【The invention's effect】
As described above, according to the present invention, when soldering a plated steel sheet, even when a flux containing no chlorine is used, the wettability of the solder is excellent, and particularly, the wettability of the solder deteriorates with time. A post-treatment liquid for plated steel sheets which provides a coating excellent in oxidation resistance and corrosion resistance, and a post-treated plated steel sheet obtained by applying and drying this post-treatment liquid for plated steel sheets to the plated steel sheet and a method for producing the same. It became possible to provide. The post-processed plated steel sheet coated with the post-treatment liquid for a plated steel sheet of the present invention has excellent solder wettability even when an inert flux containing no chlorine is used, and the solder wettability is inferior even with time. No corrosion and excellent corrosion resistance.

Claims

Post-treatment for plated steel sheet containing 100 to 800 g / L of aqueous acrylic resin, 10 to 100 g / L of rust inhibitor, 50 to 600 g / L of water-soluble rosin, and 0.5 to 100 g / L of antioxidant liquid.

A post-treatment liquid for a plated steel sheet containing 100 to 900 g / L of an aqueous urethane resin, 10 to 100 g / L of a rust inhibitor, and 0.5 to 100 g / L of an antioxidant.

The post-treatment liquid for a plated steel sheet according to claim 1 or 2, wherein the antioxidant is a phenolic antioxidant and / or a phosphorus antioxidant.

A post-treated plated steel sheet obtained by applying the post-treatment liquid for a plated steel sheet according to any one of claims 1 to 3 to a thickness of 0.05 to 10 µm after drying on the plated steel sheet.

5. The plated steel sheet according to claim 4, wherein the plated steel sheet is formed by forming any one of a zinc plating layer, a tin plating layer, a zinc-tin alloy plating layer, a copper plating layer, and a nickel plating layer on a steel sheet. 6. Post-treated plated steel sheet.

The post-treatment liquid for a plated steel sheet according to any one of claims 1 to 3, which is applied to the plated steel sheet according to the claim 5 so that the thickness after drying is 0.05 to 10 µm, and dried. Manufacturing method of post-processed plated steel sheet.