JP3903739B2 - Organic coated steel plate with excellent corrosion resistance - Google Patents

Description

【００２５】
［ 12 ］上記［1］〜［ 11 ］のいずれかの有機被覆鋼板において、複合酸化物皮膜中に含まれる成分（α）が酸化ケイ素であることを特徴とする耐食性に優れた有機被覆鋼板。
［ 13 ］上記［1］〜［ 12 ］のいずれかの有機被覆鋼板において、複合酸化物皮膜がさらに有機樹脂を含有することを特徴とする耐食性に優れた有機被覆鋼板。
［ 14 ］上記［1］〜［ 13 ］のいずれかの有機被覆鋼板において、複合酸化物皮膜は成分（α）とＰ_２Ｏ_５換算量での成分（β）とＭｇ、Ｍｎ及びＡｌの金属換算量での成分（γ）の合計付着量が６〜１０００ｍｇ／ｍ^２であり、有機皮膜は付着量が０．１ｇ／ｍ^２以上、０．５ｇ／ｍ^２未満であることを特徴とする耐食性に優れた有機被覆鋼板。
【００２８】
本発明の有機被覆鋼板の基本的な特徴は、亜鉛系めっき鋼板又はアルミニウム系めっき鋼板の表面に、第１層皮膜として、（α）酸化物微粒子と、（β）リン酸及び／又はリン酸化合物と、（γ）Ｍｇ、Ｍｎ、Ａｌの中から選ばれる１種以上の金属（但し、化合物及び／又は複合化合物として含まれる場合を含む）とを含有する（好ましくは、主成分として含有する）複合酸化物皮膜を形成し、さらにその上部に第２層皮膜として、皮膜形成有機樹脂（Ａ）と一部または全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）とを反応させることにより、皮膜形成用樹脂（Ａ）にキレート形成基としてヒドラジン誘導体（Ｃ）を付与し、この反応生成物であるキレート形成樹脂を基体樹脂として用いるとともに、自己補修性発現物質（防錆添加成分）として、（ｅ）モリブデン酸塩、（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、（ｇ）カルシウム化合物、（ｈ）リン酸塩及び／又は酸化ケイ素、（ｉ）Ｃａイオン交換シリカ、のなかから選ばれる成分を特定の組み合わせで複合添加した防錆添加成分（Ｙ）を配合した有機皮膜を形成した点にある。
【００２９】
上記の第１層皮膜と第２層皮膜は、それぞれ単独の皮膜としても従来のクロムフリー皮膜に較べて優れた防錆効果を有するが、本発明ではこれらの皮膜を下層及び上層とする二層皮膜構造とし、この二層皮膜構造による相乗効果によって薄膜の皮膜でありながらクロメート皮膜に匹敵する耐食性を得ることを可能にしたものである。このような特定の複合酸化物皮膜と有機皮膜とからなる二層皮膜構造による防食機構は必ずしも明らかでないが、以下に述べるような両皮膜による腐食抑制作用が複合化した結果であると考えられる。
【００３０】
上記第１層皮膜である複合酸化物皮膜の防食機構については必ずしも明確でないが、▲１▼緻密で難溶性の複合酸化物皮膜がバリヤー性皮膜として腐食因子を遮断すること、▲２▼酸化ケイ素などの酸化物微粒子が、リン酸及び／又はリン酸化合物とＭｇ、Ｍｎ、Ａｌの中から選ばれる１種以上の金属と共に安定で緻密なバリヤー皮膜を形成すること、▲３▼酸化物微粒子が酸化ケイ素である場合にケイ酸イオンが腐食環境下で塩基性塩化亜鉛の形成を促し、バリヤー性を向上させること、などにより優れた防食性能が得られるものと考えられる。
【００３１】
さらに皮膜に欠陥が生じた場合でも、カソード反応によってＯＨイオンが生成して界面がアルカリ性になることにより上記成分（γ）がＭｅ（ＯＨ）_２として沈殿し、緻密で難溶性の生成物として欠陥を封鎖し、腐食反応を抑制するものと考えられる。また、上述したようにリン酸および／またはリン酸化合物は複合酸化物皮膜の緻密性の向上に寄与するとともに、皮膜欠陥部で腐食反応であるアノード反応によって溶解した亜鉛イオンをリン酸成分が捕捉し、難溶性のリン酸亜鉛化合物としてそこに沈殿生成物を形成するものと考えられる。以上のように、成分（γ）とリン酸および／またはリン酸化合物は皮膜欠陥部での自己補修作用を示すものと考えられる。
【００３２】
また、上記成分（γ）の中でも、マグネシウム成分を含有する場合に特に優れた耐食性が得られる。これは、Ｍｇは他の金属に較べて水酸化物の溶解度が低く、難溶塩を形成しやすいためであると考えられる。
また、上記のような作用効果は、上述したように複合酸化物皮膜の成分（α）としてＳｉＯ_２微粒子を特定の付着量で、成分（β）としてリン酸および／またはリン酸化合物を特定の付着量で、成分（γ）としてマグネシウム成分を特定の付着量で、それぞれ含有させた場合に特に顕著に得られる。
【００３３】
上記第２層皮膜である有機皮膜の防食機構についても必ずしも明確でないが、その機構は以下のように推定できる。すなわち、単なる低分子量のキレート化剤ではなく、皮膜形成有機樹脂にヒドラジン誘導体を付与することによって、(1)緻密な有機高分子皮膜により酸素や塩素イオンなどの腐食因子を遮断する効果が得られること、(2)ヒドラジン誘導体が第１層皮膜の表面と安定で強固に結合して不動態化層を形成できること、(3)腐食反応によって溶出した亜鉛イオンを皮膜中のフリーのヒドラジン誘導体基がトラップし、安定な不溶性キレート化合物層を形成するため、界面でのイオン伝導層の形成が抑制されて腐食の進行が抑制されること、などの作用効果により腐食の進行が効果的に抑制され、優れた耐食性が得られるものと考えられる。
【００３４】
また、皮膜形成有機樹脂（Ａ）として、特にエポキシ基含有樹脂を用いた場合には、エポキシ基含有樹脂と架橋剤との反応により緻密なバリヤー皮膜が形成され、このバリヤー皮膜は酸素などの腐食因子の透過抑制能に優れ、また、分子中の水酸基により素地との優れた結合力が得られるため、特に優れた耐食性（バリヤー性）が得られる。
さらに、活性水素を有するヒドラジン誘導体（Ｃ）として、特に活性水素を有するピラゾール化合物及び／又は活性水素を有するトリアゾール化合物を用いることにより、より優れた耐食性（バリヤー性）が得られる。
【００３５】
従来技術のように皮膜形成有機樹脂に単にヒドラジン誘導体を混合しただけでは、腐食抑制の向上効果はほとんど認められない。その理由は、皮膜形成有機樹脂の分子中に組み込まれていないヒドラジン誘導体は、第１層皮膜中の金属とキレート化合物を形成するものの、そのキレート化合物は低分子量のため緻密なバリヤー層にはならないためであると考えられる。これに対して、本発明のように皮膜形成有機樹脂の分子中にヒドラジン誘導体を組み込むことにより、格段に優れた腐食抑制効果が得られる。
【００３６】
また、上記のような特定の反応生成物からなる有機皮膜中に、
（ａ）Ｃａイオン交換シリカ及びリン酸塩
（ｂ）Ｃａイオン交換シリカ、リン酸塩及び酸化ケイ素
（ｃ）カルシウム化合物及び酸化ケイ素
（ｄ）カルシウム化合物、リン酸塩及び酸化ケイ素
（ｅ）モリブデン酸塩
（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物
のうちのいずれかの、若しくは上記（ｅ）及び／又は（ｆ）に他の成分を複合添加した防錆添加成分（Ｙ）（自己補修性発現物質）を適量配合することにより、特に優れた防食性能（自己修復効果）を得ることができる。この特定の有機皮膜中に上記（ａ）〜（ｆ）の成分を配合したことにより得られる防食機構は以下のように考えられる。
【００３７】
まず、上記（ａ）〜（ｄ）の成分は沈殿作用によって自己補修性を発現するもので、その反応機構は以下のステップで進むと考えられる。
［第１ステップ］：腐食環境下において、めっき金属である亜鉛やアルミニウムよりも卑なカルシウムが優先溶解する。
［第２ステップ］：リン酸塩の場合、加水分解反応により解離したリン酸イオンと上記第１ステップで優先溶解したカルシウムイオンが錯形成反応を起こし、また酸化ケイ素の場合、表面に上記第１ステップで優先溶解したカルシウムイオンが吸着し、表面電荷を電気的中和して凝集する。その結果、いずれの場合も緻密且つ難溶性の保護皮膜が生成し、これが腐食起点を封鎖することによって腐食反応を抑制する。
【００３８】
また、上記（ｅ）の成分は不動態化効果によって自己補修性を発現する。すなわち、腐食環境下で溶存酸素と共にめっき皮膜表面に緻密な酸化物を形成し、これが腐食起点を封鎖することによって腐食反応を抑制する。
また、上記（ｆ）の成分は吸着効果によって自己補修性を発現する。すなわち、腐食によって溶出した亜鉛やアルミニウムが、上記（ｆ）の成分が有する窒素や硫黄を含む極性基に吸着して不活性皮膜を形成し、これが腐食起点を封鎖することによって腐食反応を抑制する。
一般の有機皮膜中に上記（ａ）〜（ｆ）の成分を配合した場合でも、ある程度の防食効果は得られるが、上記のように特定のキレート変性樹脂からなるバリア性に優れた有機皮膜中に上記（ａ）〜（ｆ）の自己補修性発現物質を配合することにより、両者の効果（バリア性と自己補修性）が複合化し、これにより極めて優れた防食効果が発揮されるものと考えられる。
【００３９】
また、上記（ａ）〜（ｄ）、（ｅ）、（ｆ）の各成分によって得られる自己補修効果からして、より高度な自己補修性を得るには上記（ｅ）及び／又は（ｆ）を必須成分とし、これに他の成分を複合させた以下のような組み合せの防錆添加成分（Ｙ）を調整（配合）するのが好ましく、特に、下記(5) 及び (6)の場合に最も高度な自己補修性（すなわち、耐白錆性）が得られる。
【００４０】
(1) （ｅ）モリブデン酸塩、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分
(2)
（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分
(3)
（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、及び（ｉ）Ｃａイオン交換シリカ、を配合した防錆添加成分
【００４１】
(4)
（ｅ）モリブデン酸塩、及び（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、を配合した防錆添加成分
(5)
（ｅ）モリブデン酸塩、（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分
(6)
（ｅ）モリブデン酸塩、（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、及び（ｉ）Ｃａイオン交換シリカ、を配合した防錆添加成分
【００４２】
また、本発明の有機被覆鋼板は以上述べたような機構によって高度な耐食性を有するため、これら皮膜の付着量を十分に低減させること、具体的には第１層皮膜の成分（α）とＰ_２Ｏ_５換算量での成分（β）とＭｇ、Ｍｎ及びＡｌの金属換算量での成分（γ）の合計付着量を６〜１０００ｍｇ／ｍ ^２ 、第２層皮膜の付着量を０．１ｇ／ｍ^２以上、０．５ｇ／ｍ^２未満とすることができ、これによって優れた耐食性とともに高度の導電性及びスポット溶接性を兼ね備えた有機被覆鋼板とすることができる。
【００４３】
【発明の実施の形態】
以下、本発明の詳細とその限定理由を説明する。
本発明の有機被覆鋼板のベースとなる亜鉛系めっき鋼板としては、亜鉛めっき鋼板、Ｚｎ−Ｎｉ合金めっき鋼板、Ｚｎ−Ｆｅ合金めっき鋼板（電気めっき鋼板および合金化溶融亜鉛めっき鋼板）、Ｚｎ−Ｃｒ合金めっき鋼板、Ｚｎ−Ｍｎ合金めっき鋼板、Ｚｎ−Ｃｏ合金めっき鋼板、Ｚｎ−Ｃｏ−Ｃｒ合金めっき鋼板、Ｚｎ−Ｃｒ−Ｎｉ合金めっき鋼板、Ｚｎ−Ｃｒ−Ｆｅ合金めっき鋼板、Ｚｎ−Ａｌ合金めっき鋼板（例えば、Ｚｎ−５％Ａｌ合金めっき鋼板、Ｚｎ−５５％Ａｌ合金めっき鋼板）、Ｚｎ−Ｍｇ合金めっき鋼板、Ｚｎ−Ａｌ−Ｍｇめっき鋼板、さらにはこれらのめっき鋼板のめっき皮膜中に金属酸化物、ポリマーなどを分散した亜鉛系複合めっき鋼板（例えば、Ｚｎ−ＳｉＯ _２ 分散めっき鋼板）などを用いることができる。
【００４４】
また、上記のようなめっきのうち、同種又は異種のものを２層以上めっきした複層めっき鋼板を用いることもできる。
また、本発明の有機被覆鋼板のベースとなるアルミニウム系めっき鋼板としては、アルミニウムめっき鋼板、Ａｌ−Ｓｉ合金めっき鋼板などを用いることができる。
また、めっき鋼板としては、鋼板面に予めＮｉなどの薄目付めっきを施し、その上に上記のような各種めっきを施したものであってもよい。
めっき方法としては、電解法（水溶液中での電解又は非水溶媒中での電解）、溶融法及び気相法のうち、実施可能ないずれの方法を採用することもできる。
【００４５】
また、後述するような二層皮膜をめっき皮膜表面に形成した際に皮膜欠陥やムラが生じないようにするため、必要に応じて、予めめっき皮膜表面にアルカリ脱脂、溶剤脱脂、表面調整処理（アルカリ性の表面調整処理、酸性の表面調整処理）などの処理を施しておくことができる。また、有機被覆鋼板の使用環境下での黒変（めっき表面の酸化現象の一種）を防止する目的で、必要に応じて予めめっき皮膜表面に鉄族金属イオン（Ｎｉイオン、Ｃｏイオン、Ｆｅイオン）を含む酸性又はアルカリ性水溶液による表面調整処理を施しておくこともできる。また、電気亜鉛めっき鋼板を下地鋼板として用いる場合には、黒変を防止する目的で電気めっき浴に鉄族金属イオン（Ｎｉイオン、Ｃｏイオン、Ｆｅイオン）を添加し、めっき皮膜中にこれらの金属を１ｐｐｍ以上含有させておくことができる。この場合、めっき皮膜中の鉄族金属濃度の上限については特に制限はない。
【００４６】
次に、亜鉛系めっき鋼板またはアルミニウム系めっき鋼板の表面に形成される第１層皮膜である複合酸化物皮膜について説明する。
この複合酸化物皮膜は、従来の酸化リチウムと酸化ケイ素からなる皮膜組成物に代表されるアルカリシリケート処理皮膜とは全く異なり、
（α）酸化物微粒子（好ましくは、酸化ケイ素）と、
（β）リン酸及び／又はリン酸化合物と、
（γ）Ｍｇ、Ｍｎ、Ａｌの中から選ばれる１種以上の金属（但し、化合物及び／又は複合化合物として含まれる場合を含む）と、
を含有する（好ましくは、主成分として含有する）複合酸化物皮膜である。
【００４７】
前記成分（α）である酸化物微粒子としては、耐食性の観点から特に酸化ケイ素（ＳｉＯ_２微粒子）が好ましい。また、酸化ケイ素の中でもコロイダルシリカが最も好ましい。
コロイダルシリカとしては、例えば、日産化学工業（株）製のスノーテックスＯ、スノーテックスＯＳ、スノーテックスＯＸＳ、スノーテックスＯＵＰ、スノーテックスＡＫ、スノーテックスＯ４０、スノーテックスＯＬ、スノーテックスＯＬ４０、スノーテックスＯＺＬ、スノーテックスＸＳ、スノーテックスＳ、スノーテックスＮＸＳ、スノーテックスＮＳ、スノーテックスＮ、スノーテックスＱＡＳ−２５、触媒化成工業（株）製のカタロイドＳ、カタロイドＳＩ−３５０、カタロイドＳＩ−４０、カタロイドＳＡ、カタロイドＳＮ、旭電化工業（株）製アデライトＡＴ−２０〜５０、アデライトＡＴ−２０Ｎ、アデライトＡＴ−３００、アデライトＡＴ−３００Ｓ、アデライトＡＴ２０Ｑなどを用いることができる。
【００４８】
これらの酸化ケイ素の中でも、特に粒子径が１４ｎｍ以下のもの、さらには好ましくは８ｎｍ以下のものが耐食性の観点から望ましい。
また、酸化ケイ素としては、乾式シリカ微粒子を皮膜組成物溶液に分散させたものを用いることもできる。この乾式シリカとしては、例えば、日本アエロジル（株）製アエロジル２００、アエロジル３０００、アエロジル３００ＣＦ、アエロジル３８０などを用いることができ、なかでも粒子径１２ｎｍ以下、さらに好ましくは７ｎｍ以下のものが望ましい。
【００４９】
酸化物微粒子としては、上記の酸化ケイ素のほかに、酸化アルミニウム、酸化ジルコニウム、酸化チタン、酸化セリウム、酸化アンチモンなどのコロイド溶液、微粉末などを用いることもできる。
耐食性および溶接性の観点から上記成分（α）の好ましい付着量は０．０１〜３０００ｍｇ／ｍ^２、より好ましくは０．１〜１０００ｍｇ／ｍ^２、さらに好ましくは１〜５００ｍｇ／ｍ^２である。
また、耐食性と高度の導電性及びスポット溶接性を同時に得るという観点からは、上記成分（α）の好ましい付着量は１〜６００ｍｇ／ｍ^２である。
【００５０】
前記成分（β）であるリン酸及び／又はリン酸化合物は、例えば、オルトリン酸、ピロリン酸、ポリリン酸、メタリン酸などこれらの金属塩や化合物などの１種又は２種以上を皮膜組成物中に添加することにより皮膜成分として配合することができる。また、皮膜組成物に有機リン酸やそれらの塩（例えば、フィチン酸、フィチン酸塩、ホスホン酸、ホスホン酸塩及びこれらの金属塩）の１種以上を添加してもよい。また、そのなかでも第一リン酸塩が皮膜組成物溶液の安定性の面から好適である。
【００５１】
また、リン酸塩として第一リン酸アンモニウム、第二リン酸アンモニウム、第三リン酸アンモニウムの１種以上を皮膜組成物溶液に添加すると、耐食性がより改善される傾向が認められた。その理由は明らかでないが、これらのアンモニウム塩を使用した場合には、皮膜組成物溶液のｐＨを高くしても液がゲル化しない。一般に、アルカリ域では金属塩が不溶性となるため、ｐＨの高い皮膜組成物溶液から皮膜が形成される場合に、より難溶性の化合物が乾燥過程で生じるものと考えられる。
【００５２】
皮膜中でのリン酸、リン酸化合物の存在形態も特別な限定はなく、また、結晶若しくは非結晶であるか否かも問わない。また、皮膜中でのリン酸、リン酸化合物のイオン性、溶解度についても特別な制約はない。
耐食性および溶接性などの観点から上記成分（β）の好ましい付着量はＰ_２Ｏ_５量換算で０．０１〜３０００ｍｇ／ｍ^２、より好ましくは０．１〜１０００ｍｇ／ｍ^２、さらに好ましくは１〜５００ｍｇ／ｍ^２である。
また、耐食性と高度の導電性及びスポット溶接性を同時に得るという観点からは、上記成分（β）の好ましい付着量は１〜６００ｍｇ／ｍ^２である。
【００５３】
前記成分（γ）である Ｍｇ、Ｍｎ、Ａｌの中から選ばれる１種以上の金属が皮膜中に存在する形態は特に限定されず、金属として、或いは酸化物、水酸化物、水和酸化物、リン酸化合物、配位化合物などの化合物若しくは複合化合物として存在してよい。これらの化合物、水酸化物、水和酸化物、リン酸化合物、配位化合物などのイオン性、溶解度などについても特に限定されない。
【００５４】
成分（γ）である上記各元素は皮膜中でリン酸、リン酸化合物及び酸化物微粒子と複合化合物を形成し、緻密なバリヤー性皮膜を形成して耐食性向上に寄与する。
これらの元素のうちＭｇは、腐食環境下でカソード反応によってＯＨイオンが生成して界面がアルカリ性になり、緻密で難溶性のＭｇ（ＯＨ）_２として沈殿することにより皮膜の欠陥を封鎖し、腐食反応を抑制するものと考えられる。Ｍｎは、腐食環境下でカソード反応によってＯＨイオンが生成して界面がアルカリ性になり、緻密で難溶性のリン酸塩若しくは水酸化物として沈殿することにより皮膜の欠陥を封鎖し、腐食反応を抑制するものと考えられる。また、ユーザーで鋼板表面の加工油、防錆油、揮発油等をアルカリ脱脂で洗浄する場合には、Ｍｎのリン酸塩はアルカリ環境下で溶解し難いので、極めて好適である。Ａｌは、腐食環境下でカソード反応によってＯＨイオンが生成して界面がアルカリ性になり、緻密で難溶性のリン酸塩として沈殿することにより皮膜の欠陥を封鎖し、腐食反応を抑制するものと考えられる。また、ユーザーで鋼板表面の加工油、防錆油、揮発油等をアルカリ脱脂で洗浄する場合には、Ａｌのリン酸塩はアルカリ環境下で溶解し難いので、極めて好適である。
【００５５】
皮膜中に成分（γ）を導入する方法としては、 Ｍｇ、Ｍｎ、Ａｌのリン酸塩、硫酸塩、硝酸塩、塩化物、有機酸塩などとして皮膜組成物に添加すればよい。
耐食性および皮膜外観の低下防止の観点から上記成分（γ）の好ましい付着量は金属量換算で０．０１〜１０００ｍｇ／ｍ^２、より好ましくは０．１〜５００ｍｇ／ｍ^２、さらに好ましくは１〜１００ｍｇ／ｍ^２ある。
また、耐食性と高度の導電性及びスポット溶接性を同時に得るという観点からは、上記成分（γ）の好ましい付着量は１〜６００ｍｇ／ｍ^２である。
【００５６】
複合酸化物皮膜の構成成分である、（α）酸化物微粒子と、（γ）Ｍｇ、Ｍｎ、Ａｌの中から選ばれる１種以上の金属（但し、化合物及び／又は複合化合物として含まれる場合を含む）のモル比（α）／（γ）（但し、成分（γ）は前記金属の金属換算量）は０．１〜２０、望ましくは０．１〜１０とすることが好ましい。このモル比（α）／（γ）が０．１未満では酸化物微粒子の添加効果が十分に得られず、一方、２０を超えると酸化物微粒子が皮膜の緻密化を阻害してしまう。
【００５７】
また、複合酸化物皮膜の構成成分である、（β）リン酸及び／又はリン酸化合物と、（γ）Ｍｇ、Ｍｎ、Ａｌの中から選ばれる１種以上の金属（但し、化合物及び／又は複合化合物として含まれる場合を含む）のモル比（γ）／（β）（但し、成分（β）はＰ_２Ｏ_５換算、成分（γ）は前記金属の金属量換算）は０．１〜１．５とすることが好ましい。このモル比が０．１未満では、可溶性のリン酸によって複合酸化物皮膜の難溶性が損なわれ、耐食性が低下するため好ましくない。また、モル比が１．５を超えると処理液安定性が著しく低下するため好ましくない。
【００５８】
複合酸化物皮膜中には、皮膜の加工性、耐食性を向上させることを目的として、さらに有機樹脂を配合することができる。この有機樹脂としては、エポキシ樹脂、ウレタン樹脂、アクリル樹脂、アクリル−エチレン共重合体、アクリル−スチレン共重合体、アルキド樹脂、ポリエステル樹脂、エチレン樹脂などの１種又は２種以上を用いることができる。これらは水溶性樹脂及び／又は水分散性樹脂として皮膜中に導入できる。
さらに、これらの水系樹脂に加えて、水溶性エポキシ樹脂、水溶性フェノール樹脂、水溶性ブタジエンラバー（ＳＢＲ、ＮＢＲ、ＭＢＲ）、メラミン樹脂、ブロックイソシアネート、オキサゾリン化合物などを架橋剤として併用することが有効である。
【００５９】
複合酸化物皮膜中には、耐食性をさらに向上させるための添加剤として、さらに、ポリリン酸塩、リン酸塩（例えば、リン酸亜鉛、リン酸二水素アルミニウム、亜リン酸亜鉛など）、モリブデン酸塩、リンモリブデン酸塩（例えば、リンモリブデン酸アルミニウムなど）、有機リン酸及びその塩（例えば、フィチン酸、フィチン酸塩、ホスホン酸、ホスホン酸塩及びこれらの金属塩、アルカリ金属塩など）、有機インヒビター（例えば、ヒドラジン誘導体、チオール化合物、ジチオカルバミン酸塩など）、有機化合物（例えば、ポリエチレングリコールなど）などの１種又は２種以上を配合してもよい。
【００６０】
さらに、その他の添加剤として、有機着色顔料（例えば、縮合多環系有機顔料、フタロシアニン系有機顔料など）、着色染料（例えば、有機溶剤可溶性アゾ系染料、水溶性アゾ系金属染料など）、無機顔料（例えば、酸化チタンなど）、キレート剤（例えば、チオールなど）、導電性顔料（例えば、亜鉛、アルミニウム、ニッケルなどの金属粉末、リン化鉄、アンチモンドーブ型酸化錫など）、カップリング剤（例えば、シランカップリング剤、チタンカップリング剤など）、メラミン・シアヌル酸付加物などの１種又は２種以上を添加することもできる。
【００６１】
また、複合酸化物皮膜中には、有機被覆鋼板の使用環境下での黒変（めっき表面の酸化現象の一種）を防止する目的で、鉄族金属イオン（Ｎｉイオン，Ｃｏイオン，Ｆｅイオン）の１種以上を添加してもよい。なかでもＮｉイオンの添加が最も好ましい。この場合、鉄族金属イオンの濃度としては、処理組成物中の金属量換算での成分（γ）１Ｍ（金属換算）に対して１／１００００Ｍ以上あれば所望の効果が得られる。鉄族イオン濃度の上限は特に定めないが、濃度の増加に伴い耐食性に影響を及ぼさない程度とするのが好ましく、成分（γ）１Ｍ（金属換算）に対して１Ｍ、望ましくは１／１００Ｍ程度とするのが好ましい。
【００６２】
複合酸化物皮膜の膜厚は０．００５〜３μｍ、好ましくは０．０１〜２μｍ、より好ましくは０．１〜１μｍ、さらに好ましくは０．２〜０．５μｍとする。複合酸化物皮膜の膜厚が０．００５μｍ未満では耐食性が低下する。一方、膜厚が３μｍを超えると、溶接性などの導電性が低下する。また、複合酸化物皮膜をその付着量で規定する場合、上記成分（α）、上記成分（β）のＰ_２Ｏ_５換算量、上記成分（γ）の金属換算量を含めた合計付着量を６〜３６００ｍｇ／ｍ^２、好ましくは１０〜１０００ｍｇ／ｍ^２、さらに好ましくは５０〜５００ｍｇ／ｍ^２、特に好ましくは１００〜５００ｍｇ／ｍ^２、最も好ましくは２００〜４００ｍｇ／ｍ^２とすることが適当である。この合計付着量が６ｍｇ／ｍ^２未満では耐食性が低下し、一方、合計付着量が３６００ｍｇ／ｍ^２を超えると、導電性が低下するため溶接性などが低下する。
【００６３】
また、耐食性とともに高度の導電性及びスポット溶接性を得たい場合には、上記成分（α）とＰ_２Ｏ_５換算量での上記成分（β）とＭｇ、Ｍｎ及びＡｌの金属換算量での上記（γ）の合計付着量を６〜１０００ｍｇ／ｍ^２、好ましくは１０〜６００ｍｇ／ｍ^２とすることが適当である。この合計付着量が６ｍｇ／ｍ^２未満では耐食性が不十分であり、一方、合計付着量が１０００ｍｇ／ｍ^２を超えると所望とする極めて高度な導電性及びスポット溶接性が得られない。
【００６４】
次に、上記複合酸化物皮膜の上部に第２層皮膜として形成される有機皮膜について説明する。
本発明において、複合酸化物皮膜の上部に形成される有機皮膜は、皮膜形成有機樹脂（Ａ）と一部または全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）との反応生成物（Ｘ）と、自己補修性発現物質である特定の成分が複合添加された防錆添加成分（Ｙ）とを含み、さらに、必要に応じて固形潤滑剤（Ｚ）が配合された膜厚が０．１〜５μｍの有機皮膜である。
【００６５】
皮膜形成有機樹脂（Ａ）の種類としては、一部または全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）と反応して、皮膜形成有機樹脂に活性水素含有化合物（Ｂ）が付加、縮合などの反応により結合でき、且つ皮膜を適切に形成できる樹脂であれば特別な制約はない。この皮膜形成有機樹脂（Ａ）としては、例えば、エポキシ樹脂、変性エポキシ樹脂、ポリウレタン樹脂、ポリエステル樹脂、アルキド樹脂、アクリル系共重合体樹脂、ポリブタジエン樹脂、フェノール樹脂、及びこれらの樹脂の付加物又は縮合物などを挙げることができ、これらのうちの１種を単独で又は２種以上を混合して使用することができる。
【００６６】
また、皮膜形成有機樹脂（Ａ）としては、反応性、反応の容易さ、防食性などの点から、樹脂中にエポキシ基を含有するエポキシ基含有樹脂（Ｄ）が特に好ましい。このエポキシ基含有樹脂（Ｄ）としては、一部又は全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）と反応して、皮膜形成有機樹脂に活性水素含有化合物（Ｂ）が付加、縮合などの反応により結合でき、且つ皮膜を適切に形成できる樹脂であれば特別な制約はなく、例えば、エポキシ樹脂、変性エポキシ樹脂、エポキシ基含有モノマーと共重合したアクリル系共重合体樹脂、エポキシ基を有するポリブタジエン樹脂、エポキシ基を有するポリウレタン樹脂、及びこれらの樹脂の付加物若しくは縮合物などが挙げられ、これらのエポキシ基含有樹脂の１種を単独で又は２種以上混合して用いることができる。
【００６７】
また、これらのエポキシ基含有樹脂（Ｄ）の中でも、めっき表面との密着性、耐食性の点からエポキシ樹脂、変性エポキシ樹脂が特に好適である。またその中でも、酸素などの腐食因子に対して優れた遮断性を有する熱硬化性のエポキシ樹脂や変性エポキシ樹脂が最適であり、とりわけ高度な導電性及びスポット溶接性を得るために皮膜の付着量を低レベルにする場合には特に有利である。
【００６８】
上記エポキシ樹脂としては、ビスフェノールＡ、ビスフェノールＦ、ノボラック型フェノールなどのポリフェノール類とエピクロルヒドリンなどのエピハロヒドリンとを反応させてグリシジル基を導入してなるか、若しくはこのグリシジル基導入反応生成物にさらにポリフェノール類を反応させて分子量を増大させてなる芳香族エポキシ樹脂、さらには脂肪族エポキシ樹脂、脂環族エポキシ樹脂などが挙げられ、これらの１種を単独で又は２種以上を混合して使用することができる。これらのエポキシ樹脂は、特に低温での皮膜形成性を必要とする場合には数平均分子量が１５００以上であることが好適である。
【００６９】
上記変性エポキシ樹脂としては、上記エポキシ樹脂中のエポキシ基または水酸基に各種変性剤を反応させた樹脂を挙げることができ、例えば、乾性油脂肪酸を反応させたエポキシエステル樹脂、アクリル酸又はメタクリル酸などを含有する重合性不飽和モノマー成分で変性したエポキシアクリレート樹脂、イソシアネート化合物を反応させたウレタン変性エポキシ樹脂などを例示できる。
【００７０】
上記エポキシ基含有モノマーと共重合したアクリル系共重合体樹脂としては、エポキシ基を有する不飽和モノマーとアクリル酸エステル又はメタクリル酸エステルを必須とする重合性不飽和モノマー成分とを、溶液重合法、エマルション重合法又は懸濁重合法などによって合成した樹脂を挙げることができる。
【００７１】
上記重合性不飽和モノマー成分としては、例えば、メチル（メタ）アクリレート、エチル（メタ）アクリレート、プロピル（メタ）アクリレート、ｎ−，ｉｓｏ−若しくはｔｅｒｔ−ブチル（メタ）アクリレート、ヘキシル（メタ）アクリレート、２−エチルヘキシル（メタ）アクリレート、デシル（メタ）アクリレート、ラウリル（メタ）アクリレートなどのアクリル酸又はメタクリル酸のＣ１〜２４アルキルエステル；アクリル酸、メタクリル酸、スチレン、ビニルトルエン、アクリルアミド、アクリロニトリル、Ｎ−メチロール（メタ）アクリルアミド、Ｎ−メチロール（メタ）アクリルアミドのＣ１〜４アルキルエーテル化物；Ｎ，Ｎ−ジエチルアミノエチルメタクリレートなどを挙げることができる。
【００７２】
また、エポキシ基を有する不飽和モノマーとしては、グリシジルメタクリレート、グリシジルアクリレート、３，４−エポキシシクロヘキシルメチル（メタ）アクリレートなど、エポキシ基と重合性不飽和基を持つものであれば特別な制約はない。
また、このエポキシ基含有モノマーと共重合したアクリル系共重合体樹脂は、ポリエステル樹脂、エポキシ樹脂、フェノール樹脂などによって変性させた樹脂とすることもできる。
【００７３】
前記エポキシ樹脂として特に好ましいのは、ビスフェノールＡとエピハロヒドリンとの反応生成物である下記（１）式に示される化学構造を有する樹脂であり、このエポキシ樹脂は特に耐食性に優れているため好ましい。
【化３】

このようなビスフェノールＡ型エポキシ樹脂の製造法は当業界において広く知られている。また、上記化学構造式において、ｑは０〜５０、好ましくは１〜４０、特に好ましくは２〜２０である。
なお、皮膜形成有機樹脂（Ａ）は、有機溶剤溶解型、有機溶剤分散型、水溶解型、水分散型のいずれであってもよい。
【００７４】
本発明では皮膜形成有機樹脂（Ａ）の分子中にヒドラジン誘導体を付与することを狙いとしており、このため活性水素含有化合物（Ｂ）の少なくとも一部（好ましくは全部）は、活性水素を有するヒドラジン誘導体（Ｃ）であることが必要である。
【００７５】
皮膜形成有機樹脂（Ａ）がエポキシ基含有樹脂である場合、そのエポキシ基と反応する活性水素含有化合物（Ｂ）として例えば以下に示すようなものを例示でき、これらの１種又は２種以上を使用できるが、この場合も活性水素含有化合物（Ｂ）の少なくとも一部（好ましくは全部）は、活性水素を有するヒドラジン誘導体であることが必要である。
・活性水素を有するヒドラジン誘導体
・活性水素を有する第１級または第２級のアミン化合物
・アンモニア、カルボン酸などの有機酸
・塩化水素などのハロゲン化水素
・アルコール類、チオール類
・活性水素を有しないヒドラジン誘導体または第３級アミンと酸との混合物である４級塩化剤
【００７６】
前記活性水素を有するヒドラジン誘導体（Ｃ）としては、例えば、以下のものを挙げることができる。
▲１▼ カルボヒドラジド、プロピオン酸ヒドラジド、サリチル酸ヒドラジド、アジピン酸ジヒドラジド、セバシン酸ジヒドラジド、ドデカン酸ジヒドラジド、イソフタル酸ジヒドラジド、チオカルボヒドラジド、４，４′−オキシビスベンゼンスルホニルヒドラジド、ベンゾフェノンヒドラゾン、アミノポリアクリルアミドなどのヒドラジド化合物；
▲２▼ ピラゾール、３，５−ジメチルピラゾール、３−メチル−５−ピラゾロン、３−アミノ−５−メチルピラゾールなどのピラゾール化合物；
【００７７】
▲３▼ １，２，４−トリアゾール、３−アミノ−１，２，４−トリアゾール、４−アミノ−１，２，４−トリアゾール、３−メルカプト−１，２，４−トリアゾール、５−アミノ−３−メルカプト−１，２，４−トリアゾール、２，３−ジヒドロ−３−オキソ−１，２，４−トリアゾール、１Ｈ−ベンゾトリアゾール、１−ヒドロキシベンゾトリアゾール（１水和物）、６−メチル−８−ヒドロキシトリアゾロピリダジン、６−フェニル−８−ヒドロキシトリアゾロピリダジン、５−ヒドロキシ−７−メチル−１，３，８−トリアザインドリジンなどのトリアゾール化合物；
【００７８】
▲４▼ ５−フェニル−１，２，３，４−テトラゾール、５−メルカプト−１−フェニル−１，２，３，４−テトラゾールなどのテトラゾール化合物；
▲５▼ ５−アミノ−２−メルカプト−１，３，４−チアジアゾール、２，５−ジメルカプト−１，３，４−チアジアゾールなどのチアジアゾール化合物；
▲６▼ マレイン酸ヒドラジド、６−メチル−３−ピリダゾン、４，５−ジクロロ−３−ピリダゾン、４，５−ジブロモ−３−ピリダゾン、６−メチル−４，５−ジヒドロ−３−ピリダゾンなどのピリダジン化合物
【００７９】
また、これらのなかでも、５員環または６員環の環状構造を有し、環状構造中に窒素原子を有するピラゾール化合物、トリアゾール化合物が特に好適である。
これらのヒドラジン誘導体は１種を単独で又は２種以上を混合して使用することができる。
【００８０】
活性水素含有化合物（Ｂ）の一部として使用できる上記活性水素を有するアミン化合物の代表例としては、例えば、以下のものを挙げることができる。
▲１▼ ジエチレントリアミン、ヒドロキシエチルアミノエチルアミン、エチルアミノエチルアミン、メチルアミノプロピルアミンなどの１個の２級アミノ基と１個以上の１級アミノ基を含有するアミン化合物の１級アミノ基を、ケトン、アルデヒド若しくはカルボン酸と例えば１００〜２３０℃程度の温度で加熱反応させてアルジミン、ケチミン、オキサゾリン若しくはイミダゾリンに変性した化合物；
【００８１】
▲２▼ ジエチルアミン、ジエタノールアミン、ジ−ｎ−または−ｉｓｏ−プロパノールアミン、Ｎ−メチルエタノールアミン、Ｎ−エチルエタノールアミンなどの第２級モノアミン；
▲３▼ モノエタノールアミンのようなモノアルカノールアミンとジアルキル（メタ）アクリルアミドとをミカエル付加反応により付加させて得られた第２級アミン含有化合物；
▲４▼ モノエタノールアミン、ネオペンタノールアミン、２−アミノプロパノール、３−アミノプロパノール、２−ヒドロキシ−２′（アミノプロポキシ）エチルエーテルなどのアルカノールアミンの１級アミノ基をケチミンに変性した化合物；
【００８２】
活性水素含有化合物（Ｂ）の一部として使用できる上記４級塩化剤は、活性水素を有しないヒドラジン誘導体又は第３級アミンはそれ自体ではエポキシ基と反応性を有しないので、これらをエポキシ基と反応可能とするために酸との混合物としたものである。４級塩化剤は、必要に応じて水の存在下でエポキシ基と反応し、エポキシ基含有樹脂と４級塩を形成する。
【００８３】
４級塩化剤を得るために使用される酸は、酢酸、乳酸などの有機酸、塩酸などの無機酸のいずれでもよい。また、４級塩化剤を得るために使用される活性水素を有しないヒドラジン誘導体としては、例えば３，６−ジクロロピリダジンなどを、また、第３級アミンとしては、例えば、ジメチルエタノールアミン、トリエチルアミン、トリメチルアミン、トリイソプロピルアミン、メチルジエタノールアミンなどを挙げることができる。
【００８４】
皮膜形成有機樹脂（Ａ）と一部または全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）との反応生成物（Ｘ）は、皮膜形成有機樹脂（Ａ）と活性水素含有化合物（Ｂ）とを１０〜３００℃、好ましくは５０〜１５０℃で約１〜８時間程度反応させて得られる。
【００８５】
この反応は有機溶剤を加えて行ってもよく、使用する有機溶剤の種類は特に限定されない。例えば、アセトン、メチルエチルケトン、メチルイソブチルケトン、ジブチルケトン、シクロヘキサノンなどのケトン類；エタノール、ブタノール、２−エチルヘキシルアルコール、ベンジルアルコール、エチレングリコール、エチレングリコールモノイソプロピルエーテル、エチレングリコールモノブチルエーテル、エチレングリコールモノヘキシルエーテル、プロピレングリコール、プロピレングリコールモノメチルエーテル、ジエチレングリコール、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノブチルエーテルなどの水酸基を含有するアルコール類やエーテル類；酢酸エチル、酢酸ブチル、エチレングリコールモノブチルエーテルアセテートなどのエステル類；トルエン、キシレンなどの芳香族炭化水素等を例示でき、これらの１種又は２種以上を使用することができる。また、これらのなかでエポキシ樹脂との溶解性、塗膜形成性などの面からは、ケトン系又はエーテル系の溶剤が特に好ましい。
【００８６】
皮膜形成有機樹脂（Ａ）と一部または全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）との配合比率は、固形分の割合で皮膜形成有機樹脂（Ａ）１００重量部に対して、活性水素含有化合物（Ｂ）を０．５〜２０重量部、特に好ましくは１．０〜１０重量部とするのが望ましい。
【００８７】
また、皮膜形成有機樹脂（Ａ）がエポキシ基含有樹脂（Ｄ）である場合には、エポキシ基含有樹脂（Ｄ）と活性水素含有化合物（Ｂ）との配合比率は、活性水素含有化合物（Ｂ）の活性水素基の数とエポキシ基含有樹脂（Ｄ）のエポキシ基の数との比率［活性水素基数／エポキシ基数］が０．０１〜１０、より好ましくは０．１〜８、さらに好ましくは０．２〜４とすることが耐食性などの点から適当である。
【００８８】
また、活性水素含有化合物（Ｂ）中における活性水素を有するヒドラジン誘導体（Ｃ）の割合は１０〜１００モル％、より好ましくは３０〜１００モル％、さら好ましくは４０〜１００モル％とすることが適当である。活性水素を有するヒドラジン誘導体（Ｃ）の割合が１０モル％未満では有機皮膜に十分な防錆機能を付与することができず、得られる防錆効果は皮膜形成有機樹脂とヒドラジン誘導体を単に混合して使用した場合と大差なくなる。
【００８９】
本発明では緻密なバリヤー皮膜を形成するために、樹脂組成物中に硬化剤を配合し、有機皮膜を加熱硬化させることが望ましい。
樹脂組成物皮膜を形成する場合の硬化方法としては、(1)イソシアネートと基体樹脂中の水酸基とのウレタン化反応を利用する硬化方法、(2)メラミン、尿素及びベンゾグアナミンの中から選ばれた１種以上にホルムアルデヒドを反応させてなるメチロール化合物の一部若しくは全部に炭素数１〜５の１価アルコールを反応させてなるアルキルエーテル化アミノ樹脂と基体樹脂中の水酸基との間のエーテル化反応を利用する硬化方法、が適当であるが、このうちイソシアネートと基体樹脂中の水酸基とのウレタン化反応を主反応とすることが特に好適である。
【００９０】
上記(1)の硬化方法で用いるポリイソシアネート化合物は、１分子中に少なくとも２個のイソシアネート基を有する脂肪族、脂環族（複素環を含む）又は芳香族イソシアネート化合物、若しくはそれらの化合物を多価アルコールで部分反応させた化合物である。このようなポリイソシアネート化合物としては、例えば以下のものが例示できる。
▲１▼ ｍ−又はｐ−フェニレンジイソシアネート、２，４−又は２，６−トリレンジイソシアネート、ｏ−又はｐ−キシリレンジイソシアネート、ヘキサメチレンジイソシアネート、ダイマー酸ジイソシアネート、イソホロンジイソシアネート
【００９１】
▲２▼ 上記▲１▼の化合物単独又はそれらの混合物と多価アルコール（エチレングリコール、プロピレングリコールなどの２価アルコール類；グリセリン、トリメチロールプロパンなどの３価アルコール；ペンタエリスリトールなどの４価アルコール；ソルビトール、ジペンタエリスリトールなどの６価アルコールなど）との反応生成物であって、１分子中に少なくとも２個のイソシアネートが残存する化合物
これらのポリイソシアネート化合物は、１種を単独で、または２種以上を混合して使用できる。
【００９２】
また、ポリイソシアネート化合物の保護剤（ブロック剤）としては、例えば、
▲１▼ メタノール、エタノール、プロパノール、ブタノール、オクチルアルコールなどの脂肪族モノアルコール類
▲２▼ エチレングリコール及び／又はジエチレングリコールのモノエーテル類、例えば、メチル、エチル、プロピル（ｎ−，ｉｓｏ）、ブチル（ｎ−，ｉｓｏ，ｓｅｃ）などのモノエーテル
▲３▼ フェノール、クレゾールなどの芳香族アルコール
▲４▼ アセトオキシム、メチルエチルケトンオキシムなどのオキシム
などが使用でき、これらの１種又は２種以上と前記ポリイソシアネート化合物とを反応させることにより、少なくとも常温下で安定に保護されたポリイソシアネート化合物を得ることができる。
【００９３】
このようなポリイソシアネート化合物（Ｅ）は、硬化剤として皮膜形成有機樹脂（Ａ）に対し、（Ａ）／（Ｅ）＝９５／５〜５５／４５（不揮発分の重量比）、好ましくは（Ａ）／（Ｅ）＝９０／１０〜６５／３５の割合で配合するのが適当である。ポリイソシアネート化合物には吸水性があり、これを（Ａ）／（Ｅ）＝５５／４５を超えて配合すると有機皮膜の密着性を劣化させてしまう。さらに、有機皮膜上に上塗り塗装を行った場合、未反応のポリイソシアネート化合物が塗膜中に移動し、塗膜の硬化阻害や密着性不良を起こしてしまう。このような観点から、ポリイソシアネート化合物（Ｅ）の配合量は（Ａ）／（Ｅ）＝５５／４５以下とすることが好ましい。
【００９４】
なお、皮膜形成有機樹脂（Ａ）は以上のような架橋剤（硬化剤）の添加により十分に架橋するが、さらに低温架橋性を増大させるため、公知の硬化促進触媒を使用することが望ましい。この硬化促進触媒としては、例えば、Ｎ−エチルモルホリン、ジブチル錫ジラウレート、ナフテン酸コバルト、塩化第１スズ、ナフテン酸亜鉛、硝酸ビスマスなどが使用できる。
また、例えば皮膜形成有機樹脂（Ａ）にエポキシ基含有樹脂を使用する場合、付着性など若干の物性向上を狙いとして、エポキシ基含有樹脂とともに公知のアクリル、アルキッド、ポリエステルなどの樹脂を混合して用いることもできる。
【００９５】
有機皮膜中に自己補修性発現物質である下記（ａ）〜（ｆ）のうちのいずれかの防錆添加成分（Ｙ）、
（ａ）Ｃａイオン交換シリカ及びリン酸塩
（ｂ）Ｃａイオン交換シリカ、リン酸塩及び酸化ケイ素
（ｃ）カルシウム化合物及び酸化ケイ素
（ｄ）カルシウム化合物、リン酸塩及び酸化ケイ素
（ｅ）モリブデン酸塩
（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物
若しくは上記（ｅ）及び／又は（ｆ）に他の成分を配合した防錆添加成分（Ｙ）を添加する。
これら成分（ａ）〜（ｆ）による防食機構については先に述べた通りである。
【００９６】
上記成分（ａ）、（ｂ）中に含まれるＣａイオン交換シリカは、カルシウムイオンを多孔質シリカゲル粉末の表面に固定したもので、腐食環境下でＣａイオンが放出されて沈殿膜を形成する。
Ｃａイオン交換シリカとしては任意のものを用いることができるが、平均粒子径が６μｍ以下、望ましくは４μｍ以下のものが好ましく、例えば、平均粒子径が２〜４μｍのものを用いることができる。Ｃａイオン交換シリカの平均粒子径が６μｍを超えると耐食性が低下するとともに、塗料組成物中での分散安定性が低下する。
【００９７】
Ｃａイオン交換シリカ中のＣａ濃度は１ｗｔ％以上、望ましくは２〜８ｗｔ％であることが好ましい。Ｃａ濃度が１ｗｔ％未満ではＣａ放出による防錆効果が十分に得られない。なお、Ｃａイオン交換シリカの表面積、ｐＨ、吸油量については特に限定されない。
【００９８】
以上のようなＣａイオン交換シリカとしては、商品名でW.R.Grace＆Co．製のＳＨＩＥＬＤＥＸ Ｃ３０３（平均粒子径２．５〜３．５μｍ、Ｃａ濃度３ｗｔ％）、ＳＨＩＥＬＤＥＸ ＡＣ３（平均粒子径２．３〜３．１μｍ、Ｃａ濃度６ｗｔ％）、ＳＨＩＥＬＤＥＸ ＡＣ５（平均粒子径３．８〜５．２μｍ、Ｃａ濃度６ｗｔ％）、富士シリシア化学（株）製のＳＨＩＥＬＤＥＸ（平均粒子径３μｍ、Ｃａ濃度６〜８ｗｔ％）、ＳＨＩＥＬＤＥＸ ＳＹ７１０（平均粒子径２．２〜２．５μｍ、Ｃａ濃度６．６〜７．５ｗｔ％）などを用いることができる。
【００９９】
上記成分（ａ）、（ｂ）、（ｄ）中に含まれるリン酸塩は、単塩、複塩などの全ての種類の塩を含む。また、それを構成する金属カチオンに限定はなく、リン酸亜鉛、リン酸マグネシウム、リン酸カルシウム、リン酸アルミニウムなどのいずれの金属カチオンでもよい。また、リン酸イオンの骨格や縮合度などにも限定はなく、正塩、二水素塩、一水素塩又は亜リン酸塩のいずれでもよく、さらに、正塩はオルトリン酸塩の他、ポリリン酸塩などの全ての縮合リン酸塩を含む。
【０１００】
上記成分（ｃ）、（ｄ）中に含まれるカルシウム化合物は、カルシウム酸化物、カルシウム水酸化物、カルシウム塩のいずれでもよく、これらの１種または２種以上を使用できる。また、カルシウム塩の種類にも特に制限はなく、ケイ酸カルシウム、炭酸カルシウム、リン酸カルシウムなどのようなカチオンとしてカルシウムのみを含む単塩のほか、リン酸カルシウム・亜鉛、リン酸カルシウム・マグネシウムなどのようなカルシウムとカルシウム以外のカチオンを含む複塩を使用してもよい。
【０１０１】
上記成分（ｂ）、（ｃ）、（ｄ）中に含まれる酸化ケイ素は、コロイダルシリカ、乾式シリカのいずれでもよい。コロイダルシリカとしては、水系皮膜形成樹脂をベースとする場合には、例えば、商品名で日産化学工業（株）製のスノーテックスＯ、スノーテックスＮ、スノーテックス２０、スノーテックス３０、スノーテックス４０、スノーテックスＣ、スノーテックスＳ、触媒化成工業（株）製のカタロイドＳ、カタロイドＳＩ−３５０、カタロイドＳＩ−４０、カタロイドＳＡ、カタロイドＳＮ、旭電化工業（株）製のアデライトＡＴ−２０〜５０、アデライトＡＴ−２０Ｎ、アデライトＡＴ−３００、アデライトＡＴ−３００Ｓ、アデライトＡＴ２０Ｑなどを用いることができる。
【０１０２】
また、溶剤系皮膜形成樹脂をベースとする場合には、例えば、商品名で日産化学工業（株）製のオルガノシリカゾルＭＡ−ＳＴ−Ｍ、オルガノシリカゾルＩＰＡ−ＳＴ、オルガノシリカゾルＥＧ−ＳＴ、オルガノシリカゾルＥ−ＳＴ−ＺＬ、オルガノシリカゾルＮＰＣ−ＳＴ、オルガノシリカゾルＤＭＡＣ−ＳＴ、オルガノシリカゾルＤＭＡＣ−ＳＴ−ＺＬ、オルガノシリカゾルＸＢＡ−ＳＴ、オルガノシリカゾルＭＩＢＫ−ＳＴ、触媒化成工業（株）製のＯＳＣＡＬ−１１３２、ＯＳＣＡＬ−１２３２、ＯＳＣＡＬ−１３３２、ＯＳＣＡＬ−１４３２、ＯＳＣＡＬ−１５３２、ＯＳＣＡＬ−１６３２、ＯＳＣＡＬ−１７２２などを用いることができる。
【０１０３】
特に、有機溶剤分散型シリカゾルは、分散性に優れ、ヒュームドシリカよりも耐食性に優れている。
また、ヒュームドシリカとしては、例えば、商品名で日本アエロジル（株）製のＡＥＲＯＳＩＬ Ｒ９７１、ＡＥＲＯＳＩＬ Ｒ８１２、ＡＥＲＯＳＩＬ Ｒ８１１、ＡＥＲＯＳＩＬ Ｒ９７４、ＡＥＲＯＳＩＬ Ｒ２０２、ＡＥＲＯＳＩＬ Ｒ８０５、ＡＥＲＯＳＩＬ １３０、ＡＥＲＯＳＩＬ ２００、ＡＥＲＯＳＩＬ ３００、ＡＥＲＯＳＩＬ ３００ＣＦなどを用いることができる。
【０１０４】
微粒子シリカは、腐食環境下において緻密で安定な亜鉛の腐食生成物の生成に寄与し、この腐食生成物がめっき表面に緻密に形成されることによって、腐食の促進を抑制することができると考えられている。
耐食性の観点からは、微粒子シリカは粒子径が５〜５０ｎｍ、望ましくは５〜２０ｎｍ、さらに好ましくは５〜１５ｎｍのものを用いるのが好ましい。
【０１０５】
前記成分（ｅ）のモリブデン酸塩は、その骨格、縮合度に限定はなく、例えばオルトモリブデン酸塩、パラモリブデン酸塩、メタモリブデン酸塩などが挙げられる。また、単塩、複塩などの全ての塩を含み、複塩としてはリン酸モリブデン酸塩などが挙げられる。
【０１０６】
上記成分（ｆ）の有機化合物のうち、トリアゾール類としては、１，２，４−トリアゾール、３−アミノ−１，２，４−トリアゾール、３−メルカプト−１，２，４−トリアゾール、５−アミノ−３−メルカプト−１，２，４−トリアゾール、１Ｈ−ベンゾトリアゾールなどが、またチアジアゾール類としては、５−アミノ−２−メルカプト−１，３，４−チアジアゾール、２，５−ジメルカプト−１，３，４−チアジアゾールなどが、またチアゾール類としては、２−Ｎ，Ｎ−ジエチルチオベンゾチアゾール、２−メルカプトベンゾチアゾール類などが、またチウラム類としては、テトラエチルチウラムジスルフィドなどが、それぞれ挙げられる。
【０１１１】
上記の防錆添加成分（ａ）〜（ｆ）は、先に述べたように腐食環境下において沈殿効果（成分（ａ）〜（ｄ）の場合）、不動態化効果（成分（ｅ）の場合）、吸着効果（成分（ｆ）の場合）により、それぞれ保護皮膜を形成する。
特に、基体樹脂である特定のキレート形成樹脂に上記成分（ａ）〜（ｆ）のいずれかを配合することにより、キレート形成樹脂によるバリア効果と上記成分（ａ）〜（ｆ）による自己補修効果とが複合化することによって極めて優れた防食効果が発揮される。
【０１１２】
また、上記（ａ）〜（ｄ）、（ｅ）、（ｆ）の各成分によって得られる自己補修効果（上述した３つのタイプの保護皮膜形成効果）からして、より高度な自己補修性を得るには上記（ｅ）及び／又は（ｆ）に他の成分を複合添加した以下のような組み合せの防錆添加成分（Ｙ）を調整（配合）するのが好ましく、特に、下記(5) 及び (6)の場合に最も高度な自己補修性（すなわち、耐白錆性）が得られる。
(1) （ｅ）モリブデン酸塩、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分
【０１１３】
(2)
（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分
(3)
（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、及び（ｉ）Ｃａイオン交換シリカ、を配合した防錆添加成分
(4)
（ｅ）モリブデン酸塩、及び（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、を配合した防錆添加成分
【０１１４】
(5)
（ｅ）モリブデン酸塩、（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分
(6)
（ｅ）モリブデン酸塩、（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、及び（ｉ）Ｃａイオン交換シリカ、を配合した防錆添加成分
ここで、適用し得るカルシウム化合物、リン酸塩、酸化ケイ素、Ｃａイオン交換シリカについては、先に（ａ）〜（ｄ）の成分に関して述べたものと同様である。
【０１１５】
上記(1)の（ｅ）モリブデン酸塩、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分において、これら（ｅ）、（ｇ）及び（ｈ）の配合比は固形分の重量比で（ｅ）／（ｇ）＋（ｈ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当であり、また（ｇ）／（ｈ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当である。
【０１１６】
ここで、（ｅ）／（ｇ）＋（ｈ）が１／９９未満又は９９／１超えでは、異なる自己補修効果を複合させることによる効果が十分に得られない。また、（ｇ）／（ｈ）が１／９９未満ではカルシウム溶出量が少なく、腐食起点を封鎖するだけの保護皮膜を形成できず、一方、９９／１を超えると、保護皮膜の形成にとって必要以上の量のカルシウムが溶出するばかりでなく、そのカルシウムと錯形成反応を起こすのに必要なリン酸イオンやカルシウムを吸着させるのに必要な酸化ケイ素が十分に供給されないため、十分な自己補修効果が得られない。
【０１１８】
上記(2)の（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分において、これら（ｆ）、（ｇ）及び（ｈ）の配合比は固形分の重量比で（ｆ）／（ｇ）＋（ｈ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当であり、また、（ｇ）／（ｈ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当である。
【０１１９】
ここで、（ｆ）／（ｇ）＋（ｈ）が１／９９未満又は９９／１超えでは、異なる自己補修効果を複合させることによる効果が十分に得られない。また、（ｇ）／（ｈ）が１／９９未満ではカルシウム溶出量が少なく、腐食起点を封鎖するだけの保護皮膜を形成できず、一方、９９／１を超えると、保護皮膜の形成にとって必要以上の量のカルシウムが溶出するばかりでなく、そのカルシウムと錯形成反応を起こすのに必要なリン酸イオンやカルシウムを吸着させるのに必要な酸化ケイ素が十分に供給されないため、十分な自己補修効果が得られない。
【０１２０】
上記(3)の（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物及び（ｉ）Ｃａイオン交換シリカ、を配合した防錆添加成分において、（ｆ）及び（ｉ）の配合比は固形分の重量比で（ｆ）／（ｉ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当である。
ここで、（ｆ）／（ｉ）が１／９９未満又は９９／１超えでは、異なる自己補修効果を複合させることによる効果が十分に得られない。
【０１２１】
上記(4)の（ｅ）モリブデン酸塩、及び（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、を配合した防錆添加成分において、（ｅ）及び（ｆ）の配合比は固形分の重量比で（ｅ）／（ｆ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当である。
ここで、（ｅ）／（ｆ）が１／９９未満又は９９／１超えでは、異なる自己補修効果を複合させることによる効果が十分に得られない。
【０１２２】
上記(5)の（ｅ）モリブデン酸塩、（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、（ｇ）カルシウム化合物、及び（ｈ）リン酸塩及び／又は酸化ケイ素、を配合した防錆添加成分において、これら（ｅ）、（ｆ）、（ｇ）及び（ｈ）の配合比は固形分の重量比で（ｅ）／（ｆ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当であり、（ｅ）／（ｇ）＋（ｈ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当であり、（ｆ）／（ｇ）＋（ｈ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当であり、（ｇ）／（ｈ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当である。
【０１２３】
ここで、（ｅ）／（ｆ）、（ｅ）／（ｇ）＋（ｈ）、（ｆ）／（ｇ）＋（ｈ）が、それぞれ１／９９未満又は９９／１超えでは、異なる自己補修効果を複合させることによる効果が十分に得られない。また、（ｇ）／（ｈ）が１／９９未満ではカルシウム溶出量が少なく、腐食起点を封鎖するだけの保護皮膜を形成できず、一方、９９／１を超えると、保護皮膜の形成にとって必要以上の量のカルシウムが溶出するばかりでなく、そのカルシウムと錯形成反応を起こすのに必要なリン酸イオンやカルシウムを吸着させるのに必要な酸化ケイ素が十分に供給されないため、十分な自己補修効果が得られない。
【０１２４】
上記(6)の（ｅ）モリブデン酸塩、（ｆ）トリアゾール類、チアジアゾール類、チアゾール類、チウラム類の中から選ばれる１種以上の有機化合物、及び（ｉ）Ｃａイオン交換シリカ、を配合した防錆添加成分において、これら（ｅ）、（ｆ）及び（ｉ）の配合比は固形分の重量比で（ｅ）／（ｆ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当であり、（ｅ）／（ｉ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当であり、（ｆ）／（ｉ）＝１／９９〜９９／１、好ましくは１０／９０〜９０／１０、さらに好ましくは２０／８０〜８０／２０が適当である。
ここで、（ｅ）／（ｆ）、（ｅ）／（ｉ）、（ｆ）／（ｉ）が、それぞれ１／９９未満又は９９／１超えでは、異なる自己補修効果を複合させることによる効果が十分に得られない。
【０１２５】
有機樹脂皮膜中での上記防錆添加成分（Ｙ）の配合量（複合添加した自己補修性発現物質の合計の配合量）は、皮膜形成用の樹脂組成物である反応生成物（Ｘ）（皮膜形成有機樹脂（Ａ）と一部又は全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）との反応生成物）１００重量部（固形分）に対して、１〜１００重量部（固形分）、好ましくは５〜８０重量部（固形分）、さらに好ましくは１０〜５０重量部（固形分）とする。防錆添加成分（Ｙ）の配合量が１重量部未満では耐食性向上効果が小さい。一方、配合量が１００重量部を超えると、耐食性が低下するので好ましくない。
【０１２６】
また、有機皮膜中には上記の防錆添加成分に加えて、腐食抑制剤として、他の酸化物微粒子（例えば、酸化アルミニウム、酸化ジルコニウム、酸化チタン、酸化セリウム、酸化アンチモンなど）、リンモリブデン酸塩（例えば、リンモリブデン酸アルミニウムなど）、有機リン酸及びその塩（例えば、フィチン酸、フィチン酸塩、ホスホン酸、ホスホン酸塩、及びこれらの金属塩、アルカリ金属塩、アルカリ土類金属塩など）、有機インヒビター（例えば、ヒドラジン誘導体、チオール化合物、ジチオカルバミン酸塩など）などの１種又は２種以上を添加できる。
【０１２７】
有機皮膜中には、さらに必要に応じて、皮膜の加工性を向上させる目的で固形潤滑剤（Ｚ）を配合することができる。
本発明に適用できる固形潤滑剤（Ｚ）としては、例えば、以下のようなものが挙げられ、これらの１種又は２種以上を用いることができる。
（１）ポリオレフィンワックス、パラフィンワックス：例えば、ポリエチレンワックス、合成パラフィン、天然パラフィン、マイクロワックス、塩素化炭化水素など
（２）フッ素樹脂微粒子：例えば、ポリフルオロエチレン樹脂（ポリ４フッ化エチレン樹脂など）、ポリフッ化ビニル樹脂、ポリフッ化ビニリデン樹脂など
【０１２８】
また、この他にも、脂肪酸アミド系化合物（例えば、ステアリン酸アミド、パルミチン酸アミド、メチレンビスステアロアミド、エチレンビスステアロアミド、オレイン酸アミド、エシル酸アミド、アルキレンビス脂肪酸アミドなど）、金属石けん類（例えば、ステアリン酸カルシウム、ステアリン酸鉛、ラウリン酸カルシウム、パルミチン酸カルシウムなど）、金属硫化物（例えば、二硫化モリブデン、二硫化タングステンなど）、グラファイト、フッ化黒鉛、窒化ホウ素、ポリアルキレングリコール、アルカリ金属硫酸塩などの１種又は２種以上を用いてもよい。
【０１２９】
以上の固形潤滑剤の中でも、特に、ポリエチレンワックス、フッ素樹脂微粒子（なかでも、ポリ４フッ化エチレン樹脂微粒子）が好適である。
ポリエチレンワックスとしては、例えば、ヘキスト社製のセリダスト ９６１５Ａ、セリダスト ３７１５、セリダスト ３６２０、セリダスト ３９１０、三洋化成（株）製のサンワックス １３１−Ｐ、サンワックス １６１−Ｐ、三井石油化学（株）製のケミパール Ｗ−１００、ケミパール Ｗ−２００、ケミパールＷ−５００、ケミパール Ｗ−８００、ケミパール Ｗ−９５０などを用いることができる。
【０１３０】
また、フッ素樹脂微粒子としては、テトラフルオロエチレン微粒子が最も好ましく、例えば、ダイキン工業（株）製のルブロン Ｌ−２、ルブロン Ｌ−５、三井・デュポン（株）製のＭＰ１１００、ＭＰ１２００、旭アイシーアイフロロポリマーズ（株）製のフルオンディスパージョン ＡＤ１、フルオンディスパージョン ＡＤ２、フルオン Ｌ１４１Ｊ、フルオン Ｌ１５０Ｊ、フルオン Ｌ１５５Ｊなどが好適である。
また、これらのなかで、ポリオレフィンワックスとテトラフルオロエチレン微粒子の併用により特に優れた潤滑効果が期待できる。
【０１３１】
有機皮膜中での固形潤滑剤（Ｚ）の配合量は、皮膜形成用の樹脂組成物である反応生成物（Ｘ）（皮膜形成有機樹脂（Ａ）と一部または全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）との反応生成物）１００重量部（固形分）に対して、１〜８０重量部（固形分）、好ましくは３〜４０重量部（固形分）とする。固形潤滑剤（Ｚ）の配合量が１重量部未満では潤滑効果が乏しく、一方、配合量が８０重量部を超えると塗装性が低下するので好ましくない。
【０１３２】
本発明の有機被覆鋼板が有する有機皮膜は、通常、皮膜形成有機樹脂（Ａ）と一部または全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）との反応生成物（Ｘ）（樹脂組成物）を主成分とし、これに自己補修性発現物質である特定の成分を複合添加した防錆添加成分（Ｙ）が配合され、必要に応じて、固形潤滑剤（Ｚ）及び硬化剤などが添加されるが、さらに必要に応じて、添加剤として、有機着色顔料（例えば、縮合多環系有機顔料、フタロシアニン系有機顔料など）、着色染料（例えば、有機溶剤可溶性アゾ系染料、水溶性アゾ系金属染料など）、無機顔料（例えば、酸化チタンなど）、キレート剤（例えば、チオールなど）、導電性顔料（例えば、亜鉛、アルミニウム、ニッケルなどの金属粉末、リン化鉄、アンチモンドープ型酸化錫など）、カップリング剤（例えば、シランカップリング剤、チタンカップリング剤など）、メラミン・シアヌル酸付加物などの１種又は２種以上を添加することができる。
【０１３３】
また、上記主成分および添加成分を含む皮膜形成用の塗料組成物は、通常、溶媒（有機溶剤及び／又は水）を含有し、さらに必要に応じて中和剤などが添加される。
上記有機溶剤としては、上記皮膜形成有機樹脂（Ａ）と活性水素含有化合物（Ｂ）との反応生成物（Ｘ）を溶解または分散でき、塗料組成物として調整できるものであれば特別な制約なく、例えば、先に例示した種々の有機溶剤を使用することができる。
上記中和剤は、皮膜形成有機樹脂（Ａ）を中和して水性化するために必要に応じて配合されるものであり、皮膜形成有機樹脂（Ａ）がカチオン性樹脂である場合には酢酸、乳酸、蟻酸などの酸を中和剤として使用することができる。
【０１３４】
以上述べたような有機皮膜は上記複合酸化物皮膜の上部に形成される。
有機皮膜の乾燥膜厚は０．１〜５μｍ、好ましくは０．３〜３μｍ、さらに好ましくは０．５〜２μｍとする。有機皮膜の膜厚が０．１μｍ未満では耐食性が不十分であり、一方、膜厚が５μｍを超えると導電性、加工性が低下する。
また、耐食性とともに高度の導電性及びスポット溶接性を得たい場合には、有機皮膜の付着量を０．１ｇ／ｍ^２以上、０．５ｇ／ｍ^２未満、好ましくは０．１５ｇ／ｍ^２以上、０．５ｇ／ｍ^２未満とすることが適当である。有機皮膜の付着量が０．１ｇ／ｍ^２未満では耐食性が不十分であり、一方、付着量が０．５ｇ／ｍ^２以上では所望とする極めて高度な導電性及びスポット溶接性が得られない。
【０１３５】
亜鉛めっき鋼板に表面に、表２及び表３のＮｏ．１の第１層皮膜用組成物からなる本発明条件を満足する複合酸化物皮膜（成分（α）とＰ_２Ｏ_５換算量での成分（β）とＭｇ、Ｍｎ及びＡｌの金属換算量での成分（γ）の合計付着量：３５９ｍｇ／ｍ^２）を形成し、その上部に表４のＮｏ．１の第２層皮膜用樹脂組成物（基体樹脂：熱硬化性エポキシ樹脂）の固形分１００重量部に対して表５のＮｏ．１５の防錆添加成分を１５重量部配合した皮膜用組成物からなる有機皮膜を形成した有機被覆鋼板について、有機皮膜の付着量と耐食性との関係を調べた結果を図１に、同じく有機皮膜の付着量とスポット溶接性との関係を調べた結果を図２に、同じく有機皮膜の付着量と導電性との関係を調べた結果を図３に、それぞれ示す。
なお、耐食性は［実施例１］において耐白錆性を評価した複合腐食試験（ＣＣＴ）を行い、２０サイクル後の白錆発生面積率をもとに［実施例１］と同様の評価基準で評価した。また、スポット溶接性と導電性については［実施例２］と同様の試験を行い、同様の評価基準で評価した。
【０１３６】
図１によれば有機皮膜の付着量が多くなるほど耐食性は向上し、付着量を０．１ｇ／ｍ^２以上、好ましくは０．１５ｇ／ｍ^２以上とすることにより良好な耐食性が得られていることが判る。一方、図２によれば有機皮膜の付着量が０．５ｇ／ｍ^２以上となるとスポット溶接性（スポット連続打点性）が急激に低下し、また、図３によれば有機皮膜の付着量が０．５ｇ／ｍ^２以上となると導電性も急激に悪化していることが判る。以上の理由から、優れた耐食性と特に高度な導電性及びスポット溶接性を得るためには、有機皮膜の付着量を０．１ｇ／ｍ^２以上、０．５ｇ／ｍ^２未満、好ましくは０．１５ｇ／ｍ^２以上、０．５ｇ／ｍ^２未満とすることが適当である。
【０１３７】
次に、本発明の有機被覆鋼板の製造方法について説明する。
本発明の有機被覆鋼板は、上述した複合酸化物皮膜の構成成分を含む処理液で亜鉛系めっき鋼板またはアルミニウム系めっき鋼板の表面を処理（処理液を塗布）した後、加熱乾燥させ、次いでその上層に、上述した皮膜形成有機樹脂（Ａ）と一部または全部の化合物が活性水素を有するヒドラジン誘導体（Ｃ）からなる活性水素含有化合物（Ｂ）との反応生成物（Ｘ）を含み（好ましくは主成分とする）、これに上述した特定の成分を複合添加した防錆添加成分（Ｙ）が添加され、さらに必要に応じて固形潤滑剤（Ｚ）などが添加された塗料組成物を塗布し、加熱乾燥させることにより製造される。
なお、めっき鋼板の表面は、上記処理液を塗布する前に必要に応じてアルカリ脱脂処理し、さらに密着性、耐食性を向上させるために表面調整処理などの前処理を施すことができる。
【０１３８】
亜鉛系めっき鋼板またはアルミニウム系めっき鋼板の表面を処理液で処理し、複合酸化物皮膜を形成するには、
（イ）酸化物微粒子と、
（ロ）リン酸及び／又はリン酸化合物と、
（ハ）Ｍｇ、Ｍｎ、Ａｌのうちのいずれかの金属イオン、前記金属のうちの少なくとも１種を含む水溶性イオン、前記金属のうちの少なくとも１種を含む化合物、前記金属のうちの少なくとも１種を含む複合化合物からなる群の中から選ばれる１種以上と、
を含有し、さらに必要に応じて上述した各添加成分（有機樹脂成分、鉄族金属イオン、腐食抑制剤、その他の添加剤）を添加した処理液（水溶液）で処理し、しかる後加熱乾燥させることが好ましい。
【０１３９】
ここで、上記処理液としては、前記添加成分（イ）のモル濃度、前記添加成分（ロ）のＰ _２ Ｏ _５ 換算の合計モル濃度、前記添加成分（ハ）の前記金属の金属量換算の合計モル濃度が、モル比（イ）／（ハ）＝０．１〜２０、好ましくは０．１〜１０、モル比（ハ）／（ロ）＝０．１〜１．５を満足するように調整された処理液を用いる。
前記モル比（イ）／（ハ）が０．１未満では酸化物微粒子の添加効果が十分に得られず、一方、２０を超えると酸化物微粒子が皮膜の緻密化を阻害してしまう。
また、上記モル比（ハ）／（ロ）が０．１未満ではＭｇなどの金属成分の添加に効果が十分に得られず、一方、１．５を超えると、処理液安定性が低下してしまう。
【０１４０】
添加成分（イ）である酸化物微粒子としては酸化ケイ素（ＳｉＯ _２ 微粒子）が最も好ましい。この酸化ケイ素は処理液中で安定な水分散性のシリカ微粒子であればよく、市販のシリカゾルや水分散性のケイ酸オリゴマーなどを用いることができる。但し、ヘキサフルオロケイ酸などのフッ化物は腐食性が強く、人体への影響も大きいため、作業環境への影響などの観点から使用しないことが望ましい。
処理液中での酸化物微粒子の添加量（酸化ケイ素の場合はＳｉＯ _２ 量としての添加量）は０．００１〜３．０モル／Ｌ、好ましくは０．０５〜１．０モル／Ｌ、さらに好ましくは０．１〜０．５モル／Ｌとするのが適当である。酸化物微粒子の添加量が０．００１モル／Ｌ未満では添加による効果が十分でなく、耐食性が劣る傾向がある。一方、添加量が３．０モル／Ｌを超えると皮膜の耐水性が悪くなり、結果的に耐食性も劣化する傾向がある。
【０１４１】
添加成分（ロ）であるリン酸及び／又はリン酸化合物としては、オルトリン酸、ピロリン酸、トリポリリン酸などのポリリン酸、メタリン酸及びこれらの無機塩（例えば、第一リン酸アルミニウムなど）、亜リン酸、亜リン酸塩、次亜リン酸、次亜リン酸塩などのリン酸含有の化合物が、水溶液中で溶解した際に生じるアニオン、あるいは金属カチオンとの錯イオンとして存在している形態、遊離酸として存在している形態、無機塩として水分散状態で存在している形態など全てを含み、本発明におけるリン酸成分の量は処理液中で存在するこれら全ての形態の合計をＰ _２ Ｏ _５ 換算として規定する。
【０１４２】
処理液中でのリン酸および／またはリン酸化合物の添加量はＰ _２ Ｏ _５ 換算で０．００１〜６．０モル／Ｌ、好ましくは０．０２〜１．０モル／Ｌ、さらに好ましくは０．１〜０．８モル／Ｌとするのが適当である。リン酸及び／又はリン酸化合物の添加量が０．００１モル／Ｌ未満では添加による効果が十分でなく、耐食性が劣る傾向がある。一方、添加量が６．０モル／Ｌを超えると過剰のリン酸イオンが湿潤環境においてめっき皮膜と反応し、腐食環境によってはめっき素地の腐食を促進し、変色やシミ状錆発生の要因となる。
また、添加成分（ロ）としては、耐食性の優れた複合酸化物を得ることができるため、リン酸アンモニウム塩を使用することも有効である。リン酸アンモニウム塩としては、第一リン酸アンモニウム、第二リン酸アンモニウムなどの１種または２種以上を用いることが好ましい。
【０１４３】
添加成分（ハ）の処理液中での存在形態は化合物や複合化合物でもよいが、特に優れた耐食性を得るためにはＭｇ、Ｍｎ、Ａｌの金属イオン又はＭｇ、Ｍｎ、Ａｌの金属が含まれる水溶性イオンの形態が特に好ましい。
なお、添加成分（ハ）のイオンを金属塩として供給するために、塩素イオン、硝酸イオン、硫酸イオン、酢酸イオン、ホウ酸イオンなどのアニオンが処理液中に添加されてもよい。本発明におけるＭｇ、Ｍｎ、Ａｌの成分の量は処理液中で存在するこれら全ての形態の合計を金属量換算として規定する。
処理液中での上記添加成分（ハ）の添加量は、金属量換算の合計で０．００１〜３．０モル／Ｌ、好ましくは０．０１〜０．５モル／Ｌとするのが適当である。これらの合計の添加量が０．００１モル未満では添加による効果が十分に得られず、一方、添加量が３．０モル／Ｌを超えると、逆にこれらの成分が皮膜のネットワークを阻害するようになり、緻密な皮膜ができにくくなる。また、金属成分が皮膜から溶出しやすくなり、環境によっては外観が変色するなどの欠陥を生じる。
【０１４４】
処理液中にはさらに、添加成分（ニ）として、Ｎｉ、Ｆｅ、Ｃｏのうちのいずれかの金属イオン、前記金属のうちの少なくとも１種を含む水溶性イオンからなる群の中から選ばれる１種以上を適量添加することができ、このような鉄族金属を添加することにより、鉄族金属を添加しない場合に生じる、湿潤環境下におけるめっき最表層の腐食に起因した黒変現象が回避できる。また、これらの鉄族金属のなかでも特にＮｉの効果が高く、微量でも優れた効果が認められる。但し、Ｎｉ、Ｃｏなどの鉄族金属の過剰添加は耐食性劣化につながるため、適量の添加が必要である。
【０１４５】
上記添加成分（ニ）の添加量としては、金属量換算で、金属量換算での添加成分（ハ）１モルに対して１／１００００〜１モル、望ましく１／１００００〜１／１００モルの範囲とすることが好ましい。添加成分（ニ）の添加量が添加成分（ハ）１モルに対して１／１００００モル未満では添加による効果が十分でなく、一方、添加量が１モルを超えると上記のように耐食性が劣化する。
処理液中には、上記添加成分（イ）〜（ニ）のほかに、先に述べた皮膜中への添加成分を適量添加してもよい。
処理液（水溶液）のｐＨは０．５〜５、好ましくは２〜４とすることが適当である。処理液がｐＨ０．５未満では処理液の反応性が高くなり過ぎるため皮膜に微細な欠陥部が形成され、耐食性が低下する。一方、処理液がｐＨ５を超えると処理液の反応性が低くなり、めっき皮膜と複合酸化物皮膜との界面の結合が不十分となり、この場合も耐食性が低下する傾向がある。
【０１４６】
めっき鋼板表面に処理液をコーティングする方法としては、塗布方式、浸漬方式、スプレー方式のいずれでもよく、塗布方式ではロールコーター（３ロール方式、２ロール方式など）、スクイズコーター、ダイコーターなどのいずれの塗布手段を用いてもよい。また、スクイズコーターなどによる塗布処理、浸漬処理、スプレー処理の後に、エアナイフ法やロール絞り法により塗布量の調整、外観の均一化、膜厚の均一化を行うことも可能である。
処理液の温度に特別な制約はないが、常温〜６０℃程度が適当である。常温以下では冷却などのための設備が必要となるため不経済であり、一方、６０℃を超えると水分が蒸発し易くなるため処理液の管理が難しくなる。
【０１４７】
上記のように処理液をコーティングした後、通常、水洗することなく加熱乾燥を行うが、本発明で使用する処理液は下地めっき鋼板との反応により難溶性塩を形成するため、処理後に水洗を行ってもよい。
コーティングした処理液を加熱乾燥する方法は任意であり、例えば、ドライヤー、熱風炉、高周波誘導加熱炉、赤外線炉などの手段を用いることができる。
この加熱乾燥処理は到達板温で５０〜３００℃、望ましくは８０〜２００℃、さらに望ましくは８０〜１６０℃の範囲で行うことが好ましい。加熱乾燥温度が５０℃未満では皮膜中に水分が多量に残り、耐食性が不十分となる。一方、加熱乾燥温度が３００℃を超えると非経済的であるばかりでなく、皮膜に欠陥が生じやすくなり、耐食性が低下する。
【０１４８】
以上のようにして亜鉛系めっき鋼板またはアルミニウム系めっき鋼板の表面に複合酸化物皮膜を形成した後、その上層に有機皮膜形成用の塗料組成物を塗布する。塗料組成物を塗布する方法としては、塗布法、浸漬法、スプレー法などの任意の方法を採用できる。塗布法としては、ロールコーター（３ロール方式、２ロール方式など）、スクイズコーター、ダイコーターなどのいずれの方法を用いてもよい。また、スクイズコーターなどによる塗布処理、浸漬処理またはスプレー処理の後に、エアナイフ法やロール絞り法により塗布量の調整、外観の均一化、膜厚の均一化を行うことも可能である。
【０１４９】
塗料組成物の塗布後、通常は水洗することなく、加熱乾燥を行うが、塗料組成物の塗布後に水洗工程を実施しても構わない。
加熱乾燥処理には、ドライヤー、熱風炉、高周波誘導加熱炉、赤外線炉などを用いることができる。加熱処理は、到達板温で５０〜３５０℃、好ましくは８０℃〜２５０℃の範囲で行うことが望ましい。加熱温度が５０℃未満では皮膜中の水分が多量に残り、耐食性が不十分となる。また、加熱温度が３５０℃を超えると非経済的であるばかりでなく、皮膜に欠陥が生じて耐食性が低下するおそれがある。
【０１５０】
本発明は、以上述べたような皮膜を両面または片面に有する鋼板を含むものである。したがって、本発明鋼板の形態としては、例えば、以下のようなものがある。
（１）片面：めっき皮膜−複合酸化物皮膜−有機皮膜、片面：めっき皮膜
（２）片面：めっき皮膜−複合酸化物皮膜−有機皮膜、片面：めっき皮膜−公知のリン酸塩処理皮膜など
（３）両面：めっき皮膜−複合酸化物皮膜−有機皮膜
（４）片面：めっき皮膜−複合酸化物皮膜−有機皮膜、片面：めっき皮膜−複合酸化物皮膜
（５）片面：めっき皮膜−複合酸化物皮膜−有機皮膜、片面：めっき皮膜−有機皮膜
【０１５１】
【実施例】
［実施例１］
表２及び表３に示す第１層皮膜形成用の処理液（皮膜組成物）を調整した。
また、第２層皮膜形成用の樹脂組成物（反応生成物）を以下のようにして合成した。
［合成例１］
ＥＰ８２８（油化シェルエポキシ社製，エポキシ当量１８７）１８７０部とビスフェノールＡ９１２部、テトラエチルアンモニウムブロマイド２部、メチルイソブチルケトン３００部を四つ口フラスコに仕込み、１４０℃まで昇温して４時間反応させ、エポキシ当量１３９１、固形分９０％のエポキシ樹脂を得た。このものに、エチレングリコールモノブチルエーテル１５００部を加えてから１００℃に冷却し、３，５−ジメチルピラゾール（分子量９６）を９６部とジブチルアミン（分子量１２９）を１２９部加えて、エポキシ基が消失するまで６時間反応させた後、冷却しながらメチルイソブチルケトン２０５部を加えて、固形分６０％のピラゾール変性エポキシ樹脂を得た。これを樹脂組成物（１）とする。この樹脂組成物（１）は、皮膜形成有機樹脂（Ａ）と、活性水素を有するヒドラジン誘導体（Ｃ）を５０ｍｏｌ％含む活性水素含有化合物との反応生成物である。
【０１５２】
［合成例２］
ＥＰ１００７（油化シェルエポキシ社製，エポキシ当量２０００）４０００部とエチレングリコールモノブチルエーテル２２３９部を四つ口フラスコに仕込み、１２０℃まで昇温して１時間で完全にエポキシ樹脂を溶解した。このものを１００℃に冷却し、３−アミノ−１，２，４−トリアゾール（分子量８４）を１６８部加えて、エポキシ基が消失するまで６時間反応させた後、冷却しながらメチルイソブチルケトン５４０部を加えて、固形分６０％のトリアゾール変成エポキシ樹脂を得た。これを樹脂組成物（２）とする。この樹脂組成物（２）は、皮膜形成有機樹脂（Ａ）と、活性水素を有するヒドラジン誘導体（Ｃ）を１００ｍｏｌ％含む活性水素含有化合物との反応生成物である。
【０１５３】
［合成例３］
イソホロンジイソシアネート（イソシアネート当量１１１）２２２部とメチルイソブチルケトン３４部を四つ口フラスコに仕込み、３０〜４０℃に保ってメチルエチルケトキシム（分子量８７）８７部を３時間かけて滴下後、４０℃に２時間保ち、イソシアネート当量３０９、固形分９０％の部分ブロックイソシアネートを得た。
【０１５４】
次いで、ＥＰ８２８（油化シェルエポキシ社製、エポキシ当量１８７）１４９６部とビスフェノールＡ６８４部、テトラエチルアンモニウムブロマイド１部、メチルイソブチルケトン２４１部を四つ口フラスコに仕込み、１４０℃まで昇温して４時間反応させ、エポキシ当量１０９０、固形分９０％のエポキシ樹脂を得た。このものに、メチルイソブチルケトン１０００部を加えてから１００℃に冷却し、３−メルカプト−１，２，４−トリアゾール（分子量１０１）を２０２部加えて、エポキシ基が消失するまで６時間反応させた後、上記固形分９０％の部分ブロックイソシアネートを２３０部加え１００℃で３時間反応させ、イソシアネート基が消失したことを確認した。さらに、エチレングリコールモノブチルエーテル４６１部を加えて、固形分６０％のトリアゾール変成エポキシ樹脂を得た。これを樹脂組成物（３）とする。この樹脂組成物（３）は、皮膜形成有機樹脂（Ａ）と、活性水素を有するヒドラジン誘導体（Ｃ）を１００ｍｏｌ％含む活性水素含有化合物との反応生成物である。
【０１５５】
［合成例４］
ＥＰ８２８（油化シェルエポキシ社製、エポキシ当量１８７）１８７０部とビスフェノールＡ９１２部、テトラエチルアンモニウムブロマイド２部、メチルイソブチルケトン３００部を四つ口フラスコに仕込み、１４０℃まで昇温して４時間反応させ、エポキシ当量１３９１、固形分９０％のエポキシ樹脂を得た。このものに、エチレングリコールモノブチルエーテル１５００部を加えてから１００℃に冷却し、ジブチルアミン（分子量１２９）を２５８部加えて、エポキシ基が消失するまで６時間反応させた後、冷却しながらメチルイソブチルケトン２２５部を加えて、固形分６０％のエポキシアミン付加物を得た。これを樹脂組成物（４）とする。この樹脂組成物（４）は、皮膜形成有機樹脂（Ａ）と、活性水素を有するヒドラジン誘導体（Ｃ）を含まない活性水素含有化合物との反応生成物である。
【０１５６】
上記ようにして合成された樹脂組成物（１）〜（４）に硬化剤を配合し、表４に示す樹脂組成物（塗料組成物）を作成した。これら塗料組成物には表５に示す防錆添加成分（自己補修性発現物質）、表６に示す固形潤滑剤を適宜配合し、塗料用分散機（サンドグラインダー）を用いて必要時間分散させて所望の塗料組成物とした。
【０１５７】
家電、建材、自動車部品用の有機被覆鋼板を得るため、板厚：０．８ｍｍ、表面粗さＲａ：１．０μｍの冷延鋼板に各種亜鉛系めっき又はアルミニウム系めっきを施した表１に示すめっき鋼板を処理原板として用い、このめっき鋼板の表面をアルカリ脱脂処理及び水洗乾燥した後、表２及び表３に示す処理液（皮膜組成物）をロールコーターで塗布し、加熱乾燥させて第１層皮膜を形成させた。この第１層皮膜の膜厚は、処理液の固形分（加熱残分）又は塗布条件（ロールの圧下力、回転速度など）により調整した。次いで、表４に示す塗料組成物をロールコーターにより塗布し、加熱乾燥して第２層皮膜を形成させ、本発明例及び比較例の有機被覆鋼板を製造した。第２層皮膜の膜厚は、塗料組成物の固形分（加熱残分）又は塗布条件（ロールの圧下力、回転速度など）により調整した。
【０１５８】
得られた有機被覆鋼板について、品質性能（皮膜外観、耐白錆性、アルカリ脱脂後の耐白錆性、塗料密着性、加工性）の評価を行った。その結果を第１層皮膜及び第２層皮膜の皮膜構成等とともに表７〜表３９に示す。
有機被覆鋼板の品質性能の評価は以下のようにして行った。
【０１５９】
(1) 皮膜外観
各サンプルについて、皮膜外観の均一性（ムラの有り無し）を目視で評価した。評価基準は、以下の通りである。
○：ムラが全くない均一な外観
△：ムラが若干目立つ外観
×：ムラが目立つ外観
【０１６０】
(2) 耐白錆性
各サンプルについて以下に示す複合腐食試験（ＣＣＴ）を行い、所定サイクル後の白錆発生面積率で評価した。
［複合腐食試験（ＣＣＴ）の１サイクル内容］
３ｗｔ％塩水噴霧試験（３０℃；０．５時間）
↓
湿潤試験（３０℃、９５％ＲＨ；１．５時間）
↓
熱風乾燥試験（５０℃、２０％ＲＨ；２．０時間）
↓
熱風乾燥試験（３０℃、２０％ＲＨ；２．０時間）
評価基準は、以下の通りである。
◎ ：白錆発生なし
○＋：白錆発生面積率５％未満
○ ：白錆発生面積率５％以上、１０％未満
○−：白錆面積率１０％以上、２５％未満
△ ：白錆発生面積率２５％以上、５０％未満
× ：白錆発生面積率５０％以上
【０１６１】
(3) アルカリ脱脂後の耐白錆性
各サンプルについて、日本パーカライジング（株）製のアルカリ処理液ＣＬＮ−３６４Ｓ（６０℃，スプレー２分）でアルカリ脱脂を行った後、上記の複合腐食試験（ＣＣＴ）を行い、所定サイクル後の白錆面積率で評価した。評価基準は、以下の通りである。
◎ ：白錆発生なし
○＋：白錆発生面積率５％未満
○ ：白錆発生面積率５％以上、１０％未満
○−：白錆発生面積率１０％以上、２５％未満
△ ：白錆発生面積率２５％以上、５０％未満
× ：白錆発生面積率５０％以上
【０１６２】
(4) 塗料密着性
各サンプルについて、メラミン系の焼付塗料（膜厚３０μｍ）を塗装した後、沸水中に２時間浸漬し、直ちに碁盤目（１ｍｍ間隔で１０×１０の碁盤目）のカットを入れて、粘着テープによる貼着・剥離を行い、塗膜の剥離面積率で評価した。評価基準は以下の通りである。
◎：剥離なし
○：剥離面積率５％未満
△：剥離面積率５％以上、２０％未満
×：剥離面積率２０％以上
【０１６３】
(5) 加工性
ブランク径φ１２０ｍｍ、ダイス径φ５０ｍｍで深絞り成形（無塗油条件）を行い、割れが生ずるまでの成形高さで評価した。評価基準は以下の通りである。
◎：絞り抜け
○：成形高さ３０ｍｍ以上
△：成形高さ２０ｍｍ以上、３０ｍｍ未満
×：成形高さ２０ｍｍ未満
【０１６４】
【表１】

【０１６５】
【表２】

【０１６６】
【表３】

【０１６７】
【表４】

【０１６８】
【表５】

【０１６９】
【表６】

【０１７０】
下記の表７〜表３９において、表中に記載してある *1〜*7 は以下のような内容を示す。
*1：表１に記載のめっき鋼板Ｎｏ．
*2：表２及び表３に記載の第１層皮膜用組成物Ｎｏ．
*3：成分（β）はＰ_２Ｏ_５換算の付着量、成分（γ）はＭｇ，Ｍｎ，Ａｌの金属量換算の付着量
*4：表４に記載の第２層皮膜用樹脂組成物Ｎｏ．
*5：表５に記載の防錆添加成分Ｎｏ．
*6：表６に記載の固形潤滑剤Ｎｏ．
*7：樹脂組成物の固形分１００重量部に対する配合量（重量部）
【０１７１】
【表７】

【０１７２】
【表８】

【０１７３】
【表９】

【０１７４】
【表１０】

【０１７５】
【表１１】

【０１７６】
【表１２】

【０１７７】
【表１３】

【０１７８】
【表１４】

【０１７９】
【表１５】

【０１８０】
【表１６】

【０１８１】
【表１７】

【０１８２】
【表１８】

【０１８３】
【表１９】

【０１８４】
【表２０】

【０１８５】
【表２１】

【０１８６】
【表２２】

【０１８７】
【表２３】

【０１８８】
【表２４】

【０１８９】
【表２５】

【０１９０】
【表２６】

【０１９１】
【表２７】

【０１９２】
【表２８】

【０１９３】
【表２９】

【０１９４】
【表３０】

【０１９５】
【表３１】

【０１９６】
【表３２】

【０１９７】
【表３３】

【０１９８】
【表３４】

【０１９９】
【表３５】

【０２００】
【表３６】

【０２０１】
【表３７】

【０２０２】
【表３８】

【０２０３】
【表３９】

【０２０４】
［実施例２］
家電、建材、自動車部品用の有機被覆鋼板を得るため、板厚：０．８ｍｍ、表面粗さＲａ：１．０μｍの冷延鋼板に各種亜鉛系めっき又はアルミニウム系めっきを施した表１に示すめっき鋼板を処理原板として用い、このめっき鋼板の表面をアルカリ脱脂処理及び水洗乾燥した後、表２及び表３に示す処理液（皮膜組成物）をロールコーターで塗布し、加熱乾燥させて第１層皮膜を形成させた。この第１層皮膜の付着量は、処理液の固形分（加熱残分）又は塗布条件（ロールの圧下力、回転速度など）により調整した。次いで、表４に示す塗料組成物をロールコーターにより塗布し、加熱乾燥して第２層皮膜を形成させ、本発明例及び比較例の有機被覆鋼板を製造した。第２層皮膜の付着量は、塗料組成物の固形分（加熱残分）又は塗布条件（ロールの圧下力、回転速度など）により調整した。
【０２０５】
得られた有機被覆鋼板について、品質性能（皮膜外観、耐白錆性、アルカリ脱脂後の耐白錆性、塗料密着性、加工性、スポット溶接性、導電性）の評価を行った。その結果を第１層皮膜及び第２層皮膜の皮膜構成等とともに表４０〜表５７に示す。
有機被覆鋼板のスポット溶接性と導電性の評価は以下のようにして行い、その他の性能の評価は［実施例１］と同様とした。
【０２０６】
(6) スポット溶接性
板厚１．２ｍｍの試験片を用いて、上電極ＣＲ型（元径１６ｍｍ、先端径５．４ｍｍ）、下電極Ｆ型（先端径１６ｍｍ）、加圧力３００ｋｇ、通電時間１３サイクル（６０Ｈｚ）の条件下で、スポット溶接性の連続打点試験を行い、ナゲット径が４．４ｍｍよりも小さくなった場合を溶接打点の限界とし、下記により評価した。
◎：連続打点３０００点以上
○：連続打点１０００点以上、３０００点未満
△：連続打点５００点以上、１０００点未満
×：連続打点５００点未満
【０２０７】
(7) 導電性（表面抵抗値）
４探針法抵抗率計（三菱化学（株）製「ロレスタＡＰ」）を用いて、試験片の表面抵抗を測定し、下記により評価した。
◎：表面抵抗値１０^−４Ω以下
○：表面抵抗値１０^−４Ω超、１０^−３Ω以下
△：表面抵抗値１０^−３Ω超、１０^２Ω以下
×：表面抵抗値１０^２Ω超
【０２０８】
下記の表４０〜表５７において、表中に記載してある*1〜*7は以下のような内容を示す。
*1：表１に記載のめっき鋼板Ｎｏ．
*2：表２及び表３に記載の第１層皮膜用組成物Ｎｏ．
*3：成分（β）はＰ_２Ｏ_５換算の付着量、成分（γ）はＭｇ，Ｍｎ，Ａｌの金属量換算の付着量
*4：表４に記載の第２層皮膜用樹脂組成物Ｎｏ．
*5：表５に記載の防錆添加成分Ｎｏ．
*6：表６に記載の固形潤滑剤Ｎｏ．
*7：樹脂組成物の固形分１００重量部に対する配合量（重量部）
【０２０９】
【表４０】

【０２１０】
【表４１】

【０２１１】
【表４２】

【０２１２】
【表４３】

【０２１３】
【表４４】

【０２１４】
【表４５】

【０２１５】
【表４６】

【０２１６】
【表４７】

【０２１７】
【表４８】

【０２１８】
【表４９】

【０２１９】
【表５０】

【０２２０】
【表５１】

【０２２１】
【表５２】

【０２２２】
【表５３】

【０２２３】
【表５４】

【０２２４】
【表５５】

【０２２５】
【表５６】

【０２２６】
【表５７】

【０２２７】
【発明の効果】
以上述べたように本発明の有機被覆鋼板は、製造時の処理液や製品の皮膜成分中に６価クロムを全く含まず、しかも建材、家電、自動車等の用途の有機被覆鋼板として高度の耐食性を有し、また、皮膜外観、塗料密着性等にも優れている。
また、第１層皮膜と第２層皮膜の付着量を特定の範囲に規制することにより、製品のノイズ対策から厳しい導電性が要求され、且つシャーシの組み立て工程などにおいて高い生産性を得る必要から高度のスポット溶接性が要求されるＯＡ機器、ＡＶ機器などの素材として好適な、優れた耐食性と高度な導電性及びスポット溶接性を兼ね備えた有機被覆鋼板を得ることができる。
【図面の簡単な説明】
【図１】亜鉛めっき鋼板に表面に本発明条件を満足する複合酸化物皮膜を形成し、その上部に構成成分が本発明条件を満足する有機皮膜を形成した有機被覆鋼板について、有機皮膜の付着量と耐食性との関係を示したグラフ
【図２】亜鉛めっき鋼板に表面に本発明条件を満足する複合酸化物皮膜を形成し、その上部に構成成分が本発明条件を満足する有機皮膜を形成した有機被覆鋼板について、有機皮膜の付着量とスポット溶接性との関係を示したグラフ
【図３】亜鉛めっき鋼板に表面に本発明条件を満足する複合酸化物皮膜を形成し、その上部に構成成分が本発明条件を満足する有機皮膜を形成した有機被覆鋼板について、有機皮膜の付着量と導電性との関係を示したグラフ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic coated steel sheet that is most suitable for use in automobiles, home appliances, building materials, etc., and has an effect on workers and users handling products, measures for wastewater treatment during production, and volatilization of harmful substances from products in the environment of use. -It relates to an environmentally-adapted surface-treated steel sheet that does not contain heavy metals such as chromium, lead, cadmium, and mercury at the time of manufacture and in order to adapt to environmental problems such as elution.
[0002]
[Prior art]
Steel sheets for home appliances, steel sheets for building materials, and steel sheets for automobiles have been used for the purpose of improving corrosion resistance (white rust resistance, red rust resistance) on the surface of zinc-based plated steel sheets or aluminum-based plated steel sheets. Steel plates subjected to chromate treatment with a treatment liquid mainly composed of dichromic acid or salts thereof are widely used. This chromate treatment is an economical treatment method that has excellent corrosion resistance and can be performed relatively easily.
[0003]
Chromate treatment uses hexavalent chromium, a pollution-controlling substance, but this hexavalent chromium is treated in a closed system in the treatment process, completely reduced and recovered, and not released into nature. Since the elution of chromium from the chromate film can be made almost zero by the sealing action of the organic film, the environment and the human body are not substantially contaminated by hexavalent chromium. However, due to recent global environmental problems, there is a growing trend to voluntarily reduce the use of heavy metals including hexavalent chromium. In addition, in order not to pollute the environment when the shredder dust of discarded products is dumped, there has been a movement to minimize or reduce the amount of heavy metals contained in the product.
[0004]
For this reason, in order to prevent the occurrence of white rust in the zinc-based plated steel sheet, many non-polluting treatment techniques that do not depend on chromate treatment, so-called chromium-free techniques, have been proposed. Among these, some methods using an organic compound or an organic resin have been proposed, and examples thereof include the following methods.
[0005]
(1) Method using tannic acid (for example, JP-A-51-71233)
(2) A method using a thermosetting paint in which an epoxy resin, an amino resin, and tannic acid are mixed (for example, JP-A-63-90581)
(3) A method using the chelating power of tannic acid, such as a method using a mixed composition of a water-based resin and a polyhydric phenol carboxylic acid (for example, JP-A-8-325760).
[0006]
(4) Surface treatment method in which an aqueous solution of hydrazine derivative is applied to the surface of a tin plate or a zinc iron plate (for example, Japanese Patent Publication No. 53-27694, Japanese Patent Publication No. 56-10386)
(5) A method using a rust inhibitor containing an amine addition salt obtained by adding an amine to a mixture of acyl sarcosine and benzotriazole (for example, JP-A-58-130284)
(6) A method using a treating agent in which a heterocyclic compound such as a benzothiazole compound and tannic acid are mixed (for example, JP-A-57-198267)
[0007]
[Problems to be solved by the invention]
However, these conventional techniques have the following problems.
First, all the methods (1) to (4) have a problem in terms of corrosion resistance. This is partly because the film obtained by any of the methods does not have a self-repair effect. That is, in chromate film,
(a) Barrier effect: Barrier effect against corrosion factors (water, oxygen, chlorine, etc.) due to trivalent Cr-based poorly soluble compounds (hydrated oxides)
(b) Self-repair effect: effect of protective film formation at the corrosion start point due to hexavalent Cr
High corrosion resistance is expressed by the synergistic effect of both. However, with the conventional chromium-free technology, the barrier effect can be imparted to some extent by an organic resin or the like without relying on chromium, but no self-repairing substance that can replace hexavalent Cr is provided for the self-repair effect. Therefore, high corrosion resistance could not be realized.
[0008]
In addition, the method (1) not only has insufficient corrosion resistance, but also does not provide a uniform appearance after processing. The method (2) is not intended to form a thin-film (0.1 to 5 μm) rust preventive film directly on the surface of the zinc-based or aluminum-based plating. Or even if it is applied to the surface of the aluminum-based plating as a thin film, a sufficient anticorrosion effect cannot be obtained. Similarly, the method (3) has insufficient corrosion resistance.
[0009]
Furthermore, the method (4) above is not applied to zinc-based or aluminum-based plated steel sheets, and even if applied to zinc-based or aluminum-based plated steel sheets, the resulting film does not have a network structure. There is not sufficient barrier property, and therefore corrosion resistance is insufficient. JP-B-53-23772 and JP-B-56-10386 disclose a water-soluble polymer compound (polyvinyl alcohol, maleate ester copolymer, acrylate ester copolymer) in an aqueous hydrazine derivative solution for the purpose of improving film uniformity. It is disclosed that a polymer or the like is mixed, but sufficient corrosion resistance cannot be obtained by a simple mixture of an aqueous hydrazine derivative and a water-soluble polymer compound.
[0010]
Furthermore, the above methods (5) and (6) are not intended to form a rust-preventing film on the surface of a zinc-based or aluminum-based plated steel sheet in a short time. Even if it is applied, excellent corrosion resistance cannot be obtained because it does not have barrier properties against corrosion factors such as oxygen and water. The method (6) also describes mixing with a resin (epoxy resin, acrylic resin, urethane resin, nitrocellulose resin, vinyl chloride resin, etc.) as an additive. Sufficient corrosion resistance cannot be obtained with a simple mixture of a ring compound and a resin.
[0011]
Moreover, in any of the above conditions (1) to (6), in practical conditions such as performing alkaline degreasing of about pH 9 to 11 by spraying or the like in order to remove the oil applied to the surface by pressing or the like, There exists a problem that a film | membrane peels or damages by alkali degreasing and cannot maintain corrosion resistance. Therefore, these methods are not suitable for practical use as a method of forming a rust preventive film.
[0012]
Also, recent OA equipment and AV equipment have been digitized, and strict conductivity has been required for the surface-treated steel sheet in order to prevent noise. In OA equipment, spot welding is often performed in the assembly process of the chassis, and in order to ensure high productivity, a high level of continuous spotting is required in spot welding. In the case of an organic coated steel sheet with a chromate film, it has excellent corrosion resistance with an extremely thin film, so that it can meet such demands for strict electrical conductivity and advanced continuous spotting in spot welding. In a chromium-free organic coated steel sheet, the thinner the film, the more likely the corrosion from the defective part of the film occurs, thereby causing a problem that the corrosion resistance is significantly reduced.
[0013]
Therefore, the object of the present invention is to solve such problems of the prior art, and does not contain heavy metals such as hexavalent chromium in the film, is safe and harmless in the manufacturing process and use, and has excellent corrosion resistance. Is to provide an organic coated steel sheet.
Another object of the present invention is to provide an organic coated steel sheet having both high conductivity and spot weldability as well as excellent corrosion resistance as described above.
[0014]
[Means for Solving the Problems]
As a result of intensive studies by the present inventors in order to solve the above problems, a specific composite oxide film is formed as a first layer film on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet, and the upper part thereof. By forming a specific chelate-forming resin film as the second layer film, and adding an appropriate amount of a specific self-repairing substance (rust preventive additive component) instead of hexavalent chromium in this chelate-forming resin film, It has been found that an organic-coated steel sheet having no pollution and extremely excellent corrosion resistance can be obtained without performing a chromate treatment that may adversely affect the human body. Furthermore, by regulating the adhesion amount of the first layer coating and the second layer coating of such an organic coated steel sheet to a specific range, an organic coated steel sheet having both high conductivity and spot weldability as well as excellent corrosion resistance is obtained. I found out that I could get it.
The present invention has been made on the basis of such knowledge, and the characteristic features thereof are as follows.
[0016]
[1] As a first layer coating on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet,
  (Α) oxide fine particles,
  (Β) phosphoric acid and / or a phosphoric acid compound;
  (Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
  A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (e), (g) and (h) rust preventive additive component (Y), and the blending ratio of the following (e), (g) and (h) is a solid weight ratio ( e) / (g) + (h) = 20 / 80-80 / 20, (g) / (h) = 20 / 80-80 / 20,
  (E) Molybdate
  (G) CalciumCompound
  (H) Phosphate and / or silicon oxide
  The total content of the antirust additive component (Y) is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X), and the film thickness is 0.1 An organic coated steel sheet excellent in corrosion resistance, characterized by having an organic film of 5 μm.
[0018]
[2] On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
  (Α) oxide fine particles,
  (Β) phosphoric acid and / or a phosphoric acid compound;
  (Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
  A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (f), (g) and (h) rust preventive additive component (Y), and the blending ratio of the following (f), (g) and (h) is a solid weight ratio ( f) / (g) + (h) = 20 / 80-80 / 20, (g) / (h) = 20 / 80-80 / 20,
  (F) one or more organic compounds selected from triazoles, thiadiazoles, thiazoles, and thiurams
  (G) CalciumCompound
  (H) Phosphate and / or silicon oxide
  The total content of the antirust additive component (Y) is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X), and the film thickness is 0.1 An organic coated steel sheet excellent in corrosion resistance, characterized by having an organic film of 5 μm.
[0019]
[ Three ]On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
  (Α) oxide fine particles,
  (Β) phosphoric acid and / or a phosphoric acid compound;
  (Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
  A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (f) and (i) antirust additive component (Y)In addition, the blending ratio of the following (f) and (i) is (f) / (i) = 20/80 to 80/20 as a weight ratio of the solid content,
  (F) TriazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles and thiurams
  (I) Ca ion exchange silica
  The total content of the antirust additive component (Y) is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X), and the film thickness is 0.1 An organic coated steel sheet excellent in corrosion resistance, characterized by having an organic film of 5 μm.
[0020]
[ Four ]On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
  (Α) oxide fine particles,
  (Β) phosphoric acid and / or a phosphoric acid compound;
  (Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
  A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (e) and (f) antirust additive component (Y)And the blending ratio of the following (e) and (f) is (e) / (f) = 20/80 to 80/20 in terms of the weight ratio of the solid content,
  (E) Molybdate
  (F) TriazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles and thiurams
  The total content of the antirust additive component (Y) is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X), and the film thickness is 0.1 An organic coated steel sheet excellent in corrosion resistance, characterized by having an organic film of 5 μm.
[0021]
[5] On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
  (Α) oxide fine particles,
  (Β) phosphoric acid and / or a phosphoric acid compound;
  (Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
  A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (e), (f), (g) and (h) antirust additive component (Y), and the following (e), (f), (g) and (h) (E) / (f) = 20 / 80-80 / 20, (e) / (g) + (h) = 20 / 80-80 / 20, (f) / (g) + (H) = 20 / 80-80 / 20, (g) / (h) = 20 / 80-80 / 20,
  (E) Molybdate
  (F) one or more organic compounds selected from triazoles, thiadiazoles, thiazoles, and thiurams
  (G) CalciumCompound
  (H) Phosphate and / or silicon oxide
  The total content of the antirust additive component (Y) is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X), and the film thickness is 0.1 An organic coated steel sheet excellent in corrosion resistance, characterized by having an organic film of 5 μm.
[0022]
[ 6 ]On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
  (Α) oxide fine particles,
  (Β) phosphoric acid and / or a phosphoric acid compound;
  (Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
  A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (e), (f) and (i) antirust additive component (Y)In addition, the blending ratio of the following (e), (f) and (i) is (e) / (f) = 20/80 to 80/20, (e) / (i) = 20 / 80-80 / 20, (f) / (i) = 20 / 80-80 / 20,
  (E) Molybdate
  (F) TriazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles and thiurams
  (I) Ca ion exchange silica
  The total content of the antirust additive component (Y) is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X), and the film thickness is 0.1 An organic coated steel sheet excellent in corrosion resistance, characterized by having an organic film of 5 μm.
[0023]
[ 7 ]Above [1] ~[ 6 ]In the organic coated steel sheet, the organic film further contains a solid lubricant (Z), and the content of the solid lubricant (Z) is 100 parts by weight (solid content) of the reaction product (X). 1 to 80 parts by weight (solid content), an organic coated steel sheet excellent in corrosion resistance.
[ 8 ]Above [1] ~[ 7 ]An organic coated steel sheet excellent in corrosion resistance, wherein the film-forming organic resin (A) is an epoxy group-containing resin (D).
[ 9 ]Above [1] ~[ 8 ]An organic coated steel sheet having excellent corrosion resistance, wherein the hydrazine derivative (C) having active hydrogen is a pyrazole compound having active hydrogen and / or a triazole compound having active hydrogen.
[0024]
[ Ten ]Above [1] ~[ 9 ]An organic coated steel sheet excellent in corrosion resistance, characterized in that the hydrazine derivative (C) having active hydrogen is contained in the active hydrogen compound (B) in an amount of 10 to 100 mol%.
[ 11 ]the above[ 8 ]~[ Ten ]An organic coated steel sheet excellent in corrosion resistance, wherein the epoxy group-containing resin (D) is an epoxy resin represented by the following formula (1):
[Chemical formula 2]

[0025]
[ 12 ]Above [1] ~[ 11 ]An organic coated steel sheet excellent in corrosion resistance, wherein the component (α) contained in the composite oxide film is silicon oxide.
[ 13 ]Above [1] ~[ 12 ]An organic coated steel sheet excellent in corrosion resistance, wherein the composite oxide film further contains an organic resin.
[ 14 ]Above [1] ~[ 13 ]In any one of the organic coated steel sheets, the composite oxide film contains component (α) and P₂O₅The total adhesion amount of the component (β) in the converted amount and the component (γ) in the metal converted amount of Mg, Mn and Al is 6 to 1000 mg / m²The organic film has an adhesion amount of 0.1 g / m²Or more, 0.5 g / m²An organic coated steel sheet excellent in corrosion resistance, characterized by being less than.
[0028]
  The basic feature of the organic coated steel sheet of the present invention is that (α) oxide fine particles and (β) phosphoric acid and / or phosphoric acid are formed as a first layer film on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet. A compound and (γ) one or more metals selected from Mg, Mn, and Al (including cases where they are included as a compound and / or a composite compound) (preferably, contained as a main component) ) A compound oxide film is formed, and an active hydrogen-containing compound (C) comprising a hydrazine derivative (C) in which a film forming organic resin (A) and a part or all of the compounds have active hydrogen is formed as a second layer film thereon. When the hydrazine derivative (C) is imparted as a chelate-forming group to the film-forming resin (A) by reacting with B), and the chelate-forming resin that is the reaction product is used as the base resin The self-repairing expression substances (rust-preventive component)(E)Molybdate, (f) triazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles and thiurams(G) Calcium compound, (h) Phosphate and / or silicon oxide, (i) Ca ion-exchanged silica, in a specific combinationIt is in the point which formed the organic membrane | film | coat which mix | blended the antirust addition component (Y) which carried out compound addition.
[0029]
The first layer film and the second layer film have an anticorrosive effect superior to that of conventional chromium-free films as single films, but in the present invention, these layers are two layers having a lower layer and an upper layer. With a film structure, the synergistic effect of this two-layer film structure makes it possible to obtain corrosion resistance comparable to a chromate film while being a thin film film. Although the anticorrosion mechanism by such a two-layered film structure composed of a specific complex oxide film and an organic film is not necessarily clear, it is considered that the corrosion inhibition action by both films as described below is a composite result.
[0030]
Although the anticorrosion mechanism of the composite oxide film as the first layer film is not necessarily clear, (1) the dense and hardly soluble composite oxide film acts as a barrier film to block corrosion factors, and (2) silicon oxide. The oxide fine particles such as the above form a stable and dense barrier film together with phosphoric acid and / or a phosphoric acid compound and one or more metals selected from Mg, Mn, and Al. (3) In the case of silicon oxide, it is considered that excellent anticorrosion performance can be obtained by silicate ions promoting formation of basic zinc chloride in a corrosive environment and improving barrier properties.
[0031]
Furthermore, even when a defect occurs in the film, the above component (γ) becomes Me (OH) because OH ions are generated by the cathode reaction and the interface becomes alkaline.₂It is thought that it precipitates as a dense and poorly soluble product, blocks defects, and inhibits corrosion reactions. In addition, as described above, phosphoric acid and / or phosphoric acid compounds contribute to the improvement of the denseness of the composite oxide film, and the phosphoric acid component captures zinc ions dissolved by the anodic reaction, which is a corrosion reaction, at the film defects. However, it is considered that a precipitated product is formed therein as a poorly soluble zinc phosphate compound. As described above, it is considered that the component (γ) and phosphoric acid and / or the phosphoric acid compound exhibit a self-repair action at the film defect portion.
[0032]
Further, among the above components (γ), particularly excellent corrosion resistance is obtained when a magnesium component is contained. This is presumably because Mg has a lower solubility of hydroxide than other metals and easily forms a hardly soluble salt.
In addition, as described above, the above-described effects can be obtained by using SiO as the component (α) of the composite oxide film.₂It is particularly prominent when fine particles are included in a specific adhesion amount, phosphoric acid and / or a phosphoric acid compound as a specific adhesion amount as a component (β), and a magnesium component as a component (γ) as a specific adhesion amount. Is obtained.
[0033]
Although the anticorrosion mechanism of the organic film which is the second layer film is not necessarily clear, the mechanism can be estimated as follows. In other words, by adding a hydrazine derivative to a film-forming organic resin, not just a low molecular weight chelating agent, (1) an effect of blocking corrosion factors such as oxygen and chlorine ions by a dense organic polymer film can be obtained. (2) The hydrazine derivative can be stably and firmly bonded to the surface of the first layer coating to form a passivating layer. (3) Zinc ions eluted by the corrosion reaction can be removed by free hydrazine derivative groups in the coating. In order to trap and form a stable insoluble chelate compound layer, the formation of an ion conductive layer at the interface is suppressed and the progress of corrosion is suppressed. It is considered that excellent corrosion resistance can be obtained.
[0034]
Further, when an epoxy group-containing resin is used as the film-forming organic resin (A), a dense barrier film is formed by the reaction between the epoxy group-containing resin and the crosslinking agent. It is excellent in the ability to suppress the permeation of factors, and an excellent bonding resistance to the substrate is obtained by the hydroxyl group in the molecule, so that particularly excellent corrosion resistance (barrier property) can be obtained.
Further, by using a pyrazole compound having active hydrogen and / or a triazole compound having active hydrogen as the hydrazine derivative (C) having active hydrogen, more excellent corrosion resistance (barrier property) can be obtained.
[0035]
When the hydrazine derivative is simply mixed with the film-forming organic resin as in the prior art, the effect of improving the corrosion inhibition is hardly recognized. The reason is that a hydrazine derivative not incorporated in the molecule of the film-forming organic resin forms a chelate compound with the metal in the first layer film, but the chelate compound does not become a dense barrier layer because of its low molecular weight. This is probably because of this. On the other hand, by incorporating a hydrazine derivative into the molecule of the film-forming organic resin as in the present invention, a remarkably excellent corrosion inhibiting effect can be obtained.
[0036]
  Also, aboveIn the organic film consisting of specific reaction products such as
  (A) Ca ion exchange silica and phosphate
  (B) Ca ion exchange silica, phosphate and silicon oxide
  (C) Calcium compound and silicon oxide
  (D) calcium compounds, phosphates and silicon oxides
  (E) Molybdate
  (F) TriazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles and thiurams
By adding an appropriate amount of any of the above, or the anticorrosive additive component (Y) (self-repairable substance) in which the other component is added to (e) and / or (f) above, it is particularly excellent. Anticorrosion performance (self-healing effect) can be obtained. The anticorrosion mechanism obtained by blending the components (a) to (f) in the specific organic film is considered as follows.
[0037]
First, the components (a) to (d) described above exhibit self-repairing properties by precipitation, and the reaction mechanism is considered to proceed in the following steps.
[First step]: In a corrosive environment, base calcium dissolves preferentially over zinc and aluminum which are plating metals.
[Second Step]: In the case of phosphate, the phosphate ion dissociated by the hydrolysis reaction and the calcium ion preferentially dissolved in the first step cause a complex formation reaction. In the case of silicon oxide, the first ion is formed on the surface. Calcium ions preferentially dissolved in the step are adsorbed and aggregated by electrically neutralizing the surface charge. As a result, in each case, a dense and hardly soluble protective film is formed, which inhibits the corrosion reaction by blocking the corrosion starting point.
[0038]
  The component (e) exhibits self-repairing properties due to a passivating effect. That is, a dense oxide is formed on the surface of the plating film together with dissolved oxygen in a corrosive environment, and this inhibits the corrosion reaction by blocking the corrosion starting point.
  The component (f) exhibits self-repairing properties due to the adsorption effect. That is, zinc and aluminum eluted by corrosion are adsorbed to polar groups containing nitrogen and sulfur contained in the component (f) to form an inactive film, which inhibits the corrosion reaction by blocking the corrosion starting point. .
  Even when the components (a) to (f) are blended in a general organic film, a certain degree of anticorrosive effect can be obtained.aboveAs described above, the self-repairing substances (a) to (f) described above are blended in an organic film made of a specific chelate-modified resin and having excellent barrier properties.DoThus, it is considered that both effects (barrier property and self-repairing property) are combined, and thereby an extremely excellent anticorrosion effect is exhibited.
[0039]
  In addition, from the self-repair effect obtained by the components (a) to (d), (e), and (f), the above-described (e) and / or (f) ) Is an essential component, and it is preferable to adjust (blend) the anti-rust additive component (Y) in the following combination in which other components are combined with this.(Five) as well as (6)In this case, the highest degree of self-repairability (that is, white rust resistance) can be obtained.
[0040]
(1) (e) Molybdate, (g)Calcium compoundsAnd (h) a rust-preventing additive component containing phosphate and / or silicon oxide
(2)
(F) TriazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles, thiurams, (g)Calcium compoundsAnd (h) a rust-preventing additive component containing phosphate and / or silicon oxide
(3)
(F) TriazoleKind, chiaRust-preventing additive component containing one or more organic compounds selected from diazoles, thiazoles, thiurams, and (i) Ca ion exchange silica
[0041]
(Four)
(E) molybdate and (f) triazoleKind, chiaRust preventive additive containing one or more organic compounds selected from diazoles, thiazoles and thiurams
(Five)
(E) molybdate, (f) triazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles, thiurams, (g)Calcium compoundsAnd (h) a rust-preventing additive component containing phosphate and / or silicon oxide
(6)
(E) molybdate, (f) triazoleKind, chiaRust-preventing additive component containing one or more organic compounds selected from diazoles, thiazoles, thiurams, and (i) Ca ion exchange silica
[0042]
  In addition, since the organic coated steel sheet of the present invention has high corrosion resistance by the mechanism as described above, it is possible to sufficiently reduce the adhesion amount of these films, specifically, the component (α) and P of the first layer film.₂O₅6 to 1000 mg of the total adhesion amount of the component (β) in the converted amount and the component (γ) in the metal converted amount of Mg, Mn and Al/ M ² The adhesion amount of the second layer film is 0.1 g / m²Or more, 0.5 g / m²Accordingly, an organic coated steel sheet having both high conductivity and spot weldability as well as excellent corrosion resistance can be obtained.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
  The details of the present invention and the reasons for limitation will be described below.
  Examples of the zinc-based plated steel sheet used as the base of the organic coated steel sheet of the present invention include a galvanized steel sheet, a Zn-Ni alloy-plated steel sheet, a Zn-Fe alloy-plated steel sheet (electroplated steel sheet and galvannealed steel sheet), Zn-Cr. Alloy-plated steel sheet, Zn-Mn alloy-plated steel sheet, Zn-Co alloy-plated steel sheet, Zn-Co-Cr alloy-plated steel sheet, Zn-Cr-Ni alloy-plated steel sheet, Zn-Cr-Fe alloy-plated steel sheet, Zn-Al alloy plating Steel sheets (for example, Zn-5% Al alloy-plated steel sheets, Zn-55% Al alloy-plated steel sheets), Zn-Mg alloy-plated steel sheets, Zn-Al-Mg-plated steel sheets, and metal in the plating film of these plated steel sheets Zinc-based composite plated steel plate (for example, Zn-SiO ₂ (Dispersed plated steel sheet) can be used.
[0044]
Moreover, the multilayer plating steel plate which plated two or more layers of the same kind or different kind among the above plating can also be used.
In addition, as the aluminum-based plated steel sheet that is the base of the organic-coated steel sheet of the present invention, an aluminum-plated steel sheet, an Al—Si alloy-plated steel sheet, or the like can be used.
Moreover, as a plated steel plate, the steel plate surface may be previously plated with lightness such as Ni, and various plating as described above may be performed thereon.
As a plating method, any feasible method among an electrolytic method (electrolysis in an aqueous solution or electrolysis in a nonaqueous solvent), a melting method, and a gas phase method can be adopted.
[0045]
Moreover, in order to prevent film defects and unevenness when a two-layer film as described later is formed on the surface of the plating film, alkali degreasing, solvent degreasing, surface conditioning treatment ( A treatment such as an alkaline surface conditioning treatment or an acidic surface conditioning treatment can be performed. In addition, in order to prevent blackening (a kind of oxidation phenomenon on the plating surface) under the usage environment of the organic coated steel sheet, iron group metal ions (Ni ions, Co ions, Fe ions) are previously applied to the plating film surface as necessary. ) Can also be subjected to surface conditioning treatment with an acidic or alkaline aqueous solution. In addition, when an electrogalvanized steel sheet is used as the base steel sheet, iron group metal ions (Ni ions, Co ions, Fe ions) are added to the electroplating bath for the purpose of preventing blackening, and these are added to the plating film. A metal can be contained in an amount of 1 ppm or more. In this case, there is no particular limitation on the upper limit of the iron group metal concentration in the plating film.
[0046]
Next, the composite oxide film that is the first layer film formed on the surface of the zinc-based plated steel sheet or the aluminum-based plated steel sheet will be described.
This composite oxide film is completely different from a conventional alkali silicate-treated film represented by a film composition comprising lithium oxide and silicon oxide,
(Α) oxide fine particles (preferably silicon oxide);
(Β) phosphoric acid and / or a phosphoric acid compound;
(Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
(Preferably, contained as a main component).
[0047]
The oxide fine particles as the component (α) are particularly silicon oxide (SiO 2) from the viewpoint of corrosion resistance.₂Fine particles) are preferred. Of the silicon oxides, colloidal silica is most preferable.
Examples of colloidal silica include Snowtex O, Snowtex OS, Snowtex OXS, Snowtex OUP, Snowtex AK, Snowtex O40, Snowtex OL, Snowtex OL40, Snowtex OZL manufactured by Nissan Chemical Industries, Ltd. , Snowtex XS, Snowtex S, Snowtex NXS, Snowtex NS, Snowtex N, Snowtex QAS-25, Cataloid S, Cataloid SI-350, Cataloid SI-40, Cataloid SA manufactured by Catalytic Kasei Kogyo Co., Ltd. Cataloid SN, Adelite AT-20-50 manufactured by Asahi Denka Kogyo Co., Ltd., Adelite AT-20N, Adelite AT-300, Adelite AT-300S, Adelite AT20Q, etc. can be used.
[0048]
Among these silicon oxides, those having a particle diameter of 14 nm or less, more preferably 8 nm or less are desirable from the viewpoint of corrosion resistance.
Further, as the silicon oxide, those obtained by dispersing dry silica fine particles in a coating composition solution can also be used. As this dry silica, for example, Aerosil 200, Aerosil 3000, Aerosil 300CF, Aerosil 380 manufactured by Nippon Aerosil Co., Ltd. can be used, and those having a particle diameter of 12 nm or less, more preferably 7 nm or less are desirable.
[0049]
As the oxide fine particles, in addition to the above silicon oxide, colloidal solutions such as aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, and antimony oxide, and fine powders can also be used.
From the viewpoint of corrosion resistance and weldability, the preferable amount of the component (α) is 0.01 to 3000 mg / m.², More preferably 0.1 to 1000 mg / m²More preferably 1 to 500 mg / m²It is.
In addition, from the viewpoint of obtaining corrosion resistance, high conductivity and spot weldability at the same time, the preferable amount of the component (α) is 1 to 600 mg / m.²It is.
[0050]
The phosphoric acid and / or phosphoric acid compound which is the component (β) includes, for example, one or more of these metal salts and compounds such as orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, and metaphosphoric acid in the coating composition. It can mix | blend as a film | membrane component by adding to. Moreover, you may add 1 or more types of organic phosphoric acid and those salts (for example, phytic acid, phytate, phosphonic acid, phosphonate, and these metal salts) to a film | membrane composition. Of these, the primary phosphate is preferable from the viewpoint of the stability of the coating composition solution.
[0051]
Moreover, when 1 or more types of the primary ammonium phosphate, the secondary ammonium phosphate, and the tertiary ammonium phosphate were added to the coating composition solution as a phosphate, the tendency which corrosion resistance improved more was recognized. The reason is not clear, but when these ammonium salts are used, the liquid does not gel even if the pH of the coating composition solution is increased. In general, since a metal salt becomes insoluble in an alkaline region, it is considered that a less soluble compound is produced during the drying process when a film is formed from a film composition solution having a high pH.
[0052]
The presence form of phosphoric acid and phosphoric acid compound in the film is not particularly limited, and it may be crystal or non-crystalline. There are no particular restrictions on the ionicity and solubility of phosphoric acid and phosphoric acid compounds in the film.
From the viewpoints of corrosion resistance and weldability, the preferable amount of the component (β) is P₂O₅0.01-3000mg / m in terms of quantity², More preferably 0.1 to 1000 mg / m²More preferably 1 to 500 mg / m²It is.
Further, from the viewpoint of obtaining corrosion resistance and high conductivity and spot weldability at the same time, the preferable amount of the component (β) is 1 to 600 mg / m.²It is.
[0053]
The form in which one or more metals selected from Mg, Mn, and Al as the component (γ) are present in the film is not particularly limited, and may be a metal or an oxide, hydroxide, or hydrated oxide. , Phosphate compounds, coordination compounds and the like or complex compounds. There is no particular limitation on the ionicity and solubility of these compounds, hydroxides, hydrated oxides, phosphate compounds, coordination compounds, and the like.
[0054]
Each element as the component (γ) forms a complex compound with phosphoric acid, a phosphoric acid compound and oxide fine particles in the film, thereby forming a dense barrier film and contributing to improvement of corrosion resistance.
Among these elements, Mg is formed of OH ions by a cathode reaction in a corrosive environment to make the interface alkaline, and it is dense and hardly soluble Mg (OH).₂By precipitating, the defects of the film are blocked and the corrosion reaction is suppressed. Mn generates OH ions by the cathodic reaction in a corrosive environment, making the interface alkaline, and precipitating as a dense and sparingly soluble phosphate or hydroxide, thereby blocking defects in the film and suppressing the corrosion reaction. It is thought to do. In addition, when the user cleans processing oil, rust preventive oil, volatile oil, etc. on the surface of the steel sheet by alkaline degreasing, Mn phosphate is very suitable because it is difficult to dissolve in an alkaline environment. Al is considered that OH ions are generated by the cathodic reaction in a corrosive environment, the interface becomes alkaline, and precipitates as a dense and sparingly soluble phosphate, thereby blocking defects in the film and suppressing the corrosion reaction. It is done. Further, when the user cleans processing oil, rust preventive oil, volatile oil, etc. on the surface of the steel sheet by alkaline degreasing, Al phosphate is extremely suitable because it is difficult to dissolve in an alkaline environment.
[0055]
As a method for introducing the component (γ) into the film, it may be added to the film composition as Mg, Mn, Al phosphate, sulfate, nitrate, chloride, organic acid salt or the like.
From the viewpoint of corrosion resistance and prevention of deterioration of the film appearance, the preferable amount of the component (γ) is 0.01 to 1000 mg / m in terms of metal amount.², More preferably 0.1 to 500 mg / m²More preferably 1 to 100 mg / m²is there.
Further, from the viewpoint of obtaining corrosion resistance, high conductivity and spot weldability at the same time, the preferable amount of the component (γ) is 1 to 600 mg / m.²It is.
[0056]
(Α) Oxide fine particles and (γ) Mg, Mn, Al, or one or more kinds of metals (provided that they are included as a compound and / or a composite compound) The molar ratio (included) (α) / (γ) (where component (γ) is the metal equivalent of the metal) is 0.1-20, preferably 0.1-10. When the molar ratio (α) / (γ) is less than 0.1, the effect of adding oxide fine particles cannot be sufficiently obtained. On the other hand, when the molar ratio (α) / (γ) exceeds 20, the oxide fine particles inhibit the densification of the film.
[0057]
In addition, (β) phosphoric acid and / or a phosphoric acid compound, and (γ) Mg, Mn, Al, which are constituents of the composite oxide film, and one or more metals selected from the group consisting of compound and / or Molar ratio (γ) / (β) (including component (β) is P)₂O₅In terms of conversion, component (γ) is preferably 0.1 to 1.5 in terms of the metal amount of the metal. If this molar ratio is less than 0.1, the poor solubility of the composite oxide film is impaired by soluble phosphoric acid, and the corrosion resistance is lowered. On the other hand, when the molar ratio exceeds 1.5, the stability of the processing solution is remarkably lowered.
[0058]
An organic resin can be further blended in the composite oxide film for the purpose of improving the workability and corrosion resistance of the film. As this organic resin, one or more of epoxy resin, urethane resin, acrylic resin, acrylic-ethylene copolymer, acrylic-styrene copolymer, alkyd resin, polyester resin, ethylene resin and the like can be used. . These can be introduced into the film as a water-soluble resin and / or a water-dispersible resin.
In addition to these water-based resins, it is effective to use a water-soluble epoxy resin, water-soluble phenol resin, water-soluble butadiene rubber (SBR, NBR, MBR), melamine resin, blocked isocyanate, oxazoline compound, etc. as a crosslinking agent. It is.
[0059]
In the composite oxide film, as an additive for further improving the corrosion resistance, polyphosphate, phosphate (for example, zinc phosphate, aluminum dihydrogen phosphate, zinc phosphite, etc.), molybdic acid Salts, phosphomolybdates (eg, aluminum phosphomolybdate), organophosphoric acids and salts thereof (eg, phytic acid, phytate, phosphonic acid, phosphonate and their metal salts, alkali metal salts, etc.), You may mix | blend 1 type (s) or 2 or more types, such as organic inhibitors (for example, a hydrazine derivative, a thiol compound, dithiocarbamate, etc.), an organic compound (for example, polyethylene glycol etc.).
[0060]
Further, as other additives, organic coloring pigments (for example, condensed polycyclic organic pigments, phthalocyanine organic pigments, etc.), coloring dyes (for example, organic solvent-soluble azo dyes, water-soluble azo metal dyes, etc.), inorganic Pigment (for example, titanium oxide), chelating agent (for example, thiol), conductive pigment (for example, metal powder such as zinc, aluminum, nickel, iron phosphide, antimony dove type tin oxide), coupling agent (for example) For example, a silane coupling agent, a titanium coupling agent, etc.), 1 type, or 2 or more types, such as a melamine cyanuric acid adduct, can also be added.
[0061]
Also, in the complex oxide film, iron group metal ions (Ni ions, Co ions, Fe ions) are used for the purpose of preventing blackening (a kind of oxidation phenomenon on the plating surface) under the usage environment of the organic coated steel sheet. One or more of these may be added. Of these, addition of Ni ions is most preferable. In this case, if the concentration of the iron group metal ion is 1 / 10,000 M or more with respect to the component (γ) 1 M (metal conversion) in terms of the amount of metal in the treatment composition, a desired effect can be obtained. Although the upper limit of the iron group ion concentration is not particularly defined, it is preferably set to an extent that does not affect the corrosion resistance as the concentration increases, and is preferably 1M with respect to the component (γ) 1M (metal conversion), desirably about 1 / 100M. Is preferable.
[0062]
The film thickness of the composite oxide film is 0.005 to 3 μm, preferably 0.01 to 2 μm, more preferably 0.1 to 1 μm, and still more preferably 0.2 to 0.5 μm. When the film thickness of the composite oxide film is less than 0.005 μm, the corrosion resistance is lowered. On the other hand, when the film thickness exceeds 3 μm, conductivity such as weldability is lowered. Further, when the composite oxide film is defined by the amount of adhesion, the component (α), P of the component (β)₂O₅6-3600 mg / m of total adhesion amount including conversion amount and metal conversion amount of the above component (γ)², Preferably 10 to 1000 mg / m²More preferably, 50 to 500 mg / m², Particularly preferably 100 to 500 mg / m², Most preferably 200-400 mg / m²Is appropriate. This total adhesion amount is 6 mg / m²If it is less than 1, the corrosion resistance is lowered, while the total adhesion amount is 3600 mg / m.²If it exceeds 1, the conductivity is lowered, so that the weldability is lowered.
[0063]
When it is desired to obtain high conductivity and spot weldability as well as corrosion resistance, the above component (α) and P₂O₅The total adhesion amount of the component (β) in terms of the converted amount and the above (γ) in terms of the metal equivalent amounts of Mg, Mn and Al is 6 to 1000 mg / m.², Preferably 10 to 600 mg / m²Is appropriate. This total adhesion amount is 6 mg / m²If the ratio is less than 1, the corrosion resistance is insufficient. On the other hand, the total adhesion amount is 1000 mg / m.²If it exceeds 1, the desired extremely high conductivity and spot weldability cannot be obtained.
[0064]
  Next, the organic film formed as the second layer film on the complex oxide film will be described.
  In the present invention, the organic film formed on the upper part of the composite oxide film is an active hydrogen-containing compound (B) comprising a film-forming organic resin (A) and a hydrazine derivative (C) in which some or all of the compounds have active hydrogen. ) Reaction product (X) and self-repairing substanceRust prevention with compound addition of certain componentsIt is an organic film having a film thickness of 0.1 to 5 μm including an additive component (Y), and further containing a solid lubricant (Z) as required.
[0065]
As the kind of the film-forming organic resin (A), a part or all of the compounds react with the active hydrogen-containing compound (B) made of the hydrazine derivative (C) having active hydrogen, so that the film-forming organic resin contains active hydrogen. There is no particular limitation as long as the compound (B) can be bonded by a reaction such as addition or condensation and can form a film appropriately. Examples of the film-forming organic resin (A) include epoxy resins, modified epoxy resins, polyurethane resins, polyester resins, alkyd resins, acrylic copolymer resins, polybutadiene resins, phenol resins, and adducts of these resins or A condensate etc. can be mentioned, One of these can be used individually or in mixture of 2 or more types.
[0066]
The film-forming organic resin (A) is particularly preferably an epoxy group-containing resin (D) containing an epoxy group in the resin from the viewpoints of reactivity, easiness of reaction, anticorrosion, and the like. As the epoxy group-containing resin (D), a part or all of the compounds react with the active hydrogen-containing compound (B) composed of the hydrazine derivative (C) having active hydrogen to form an active hydrogen-containing compound in the film-forming organic resin. There is no special limitation as long as (B) is a resin that can be bonded by a reaction such as addition or condensation and can form a film appropriately. For example, an acrylic resin copolymerized with an epoxy resin, a modified epoxy resin, or an epoxy group-containing monomer. Examples include copolymer resins, polybutadiene resins having an epoxy group, polyurethane resins having an epoxy group, and adducts or condensates of these resins. One of these epoxy group-containing resins may be used alone or in combination of two or more. It can be used by mixing.
[0067]
Of these epoxy group-containing resins (D), epoxy resins and modified epoxy resins are particularly preferred from the viewpoints of adhesion to the plating surface and corrosion resistance. Among them, thermosetting epoxy resins and modified epoxy resins that have excellent barrier properties against corrosion factors such as oxygen are the most suitable, and in particular, the coating amount to obtain high conductivity and spot weldability. It is particularly advantageous when the level is low.
[0068]
As the epoxy resin, polyphenols such as bisphenol A, bisphenol F, and novolac type phenol are reacted with epihalohydrin such as epichlorohydrin to introduce glycidyl groups, or polyphenols are further added to the glycidyl group introduction reaction product. An aromatic epoxy resin obtained by reacting with an aromatic epoxy resin, an aliphatic epoxy resin, an alicyclic epoxy resin, and the like can be used. One of these can be used alone or a mixture of two or more can be used. Can do. These epoxy resins preferably have a number average molecular weight of 1500 or more, particularly when film formation at low temperatures is required.
[0069]
Examples of the modified epoxy resin include resins obtained by reacting various modifiers with epoxy groups or hydroxyl groups in the epoxy resin, such as epoxy ester resins, acrylic acid or methacrylic acid obtained by reacting a dry oil fatty acid. An epoxy acrylate resin modified with a polymerizable unsaturated monomer component containing styrene, a urethane-modified epoxy resin reacted with an isocyanate compound, and the like can be exemplified.
[0070]
As the acrylic copolymer resin copolymerized with the epoxy group-containing monomer, an unsaturated monomer having an epoxy group and a polymerizable unsaturated monomer component essentially comprising an acrylic ester or a methacrylic ester, a solution polymerization method, Examples thereof include resins synthesized by an emulsion polymerization method or a suspension polymerization method.
[0071]
Examples of the polymerizable unsaturated monomer component include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-, iso- or tert-butyl (meth) acrylate, hexyl (meth) acrylate, C1-24 alkyl ester of acrylic acid or methacrylic acid such as 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate; acrylic acid, methacrylic acid, styrene, vinyltoluene, acrylamide, acrylonitrile, N- Examples thereof include methylol (meth) acrylamide, C1-4 alkyl etherified product of N-methylol (meth) acrylamide; N, N-diethylaminoethyl methacrylate and the like.
[0072]
The unsaturated monomer having an epoxy group is not particularly limited as long as it has an epoxy group and a polymerizable unsaturated group, such as glycidyl methacrylate, glycidyl acrylate, and 3,4-epoxycyclohexylmethyl (meth) acrylate. .
The acrylic copolymer resin copolymerized with the epoxy group-containing monomer may be a resin modified with a polyester resin, an epoxy resin, a phenol resin, or the like.
[0073]
Particularly preferred as the epoxy resin is a resin having a chemical structure represented by the following formula (1), which is a reaction product of bisphenol A and epihalohydrin, and this epoxy resin is particularly preferable because of its excellent corrosion resistance.
[Chemical Formula 3]

A method for producing such a bisphenol A type epoxy resin is widely known in the art. Moreover, in the said chemical structural formula, q is 0-50, Preferably it is 1-40, Most preferably, it is 2-20.
The film-forming organic resin (A) may be any of an organic solvent dissolution type, an organic solvent dispersion type, a water dissolution type, and a water dispersion type.
[0074]
The present invention aims to provide a hydrazine derivative in the molecule of the film-forming organic resin (A). Therefore, at least part (preferably all) of the active hydrogen-containing compound (B) is hydrazine having active hydrogen. It must be a derivative (C).
[0075]
In the case where the film-forming organic resin (A) is an epoxy group-containing resin, examples of the active hydrogen-containing compound (B) that reacts with the epoxy group include the following, and one or more of these may be exemplified In this case as well, at least a part (preferably all) of the active hydrogen-containing compound (B) needs to be a hydrazine derivative having active hydrogen.
・ Hydrazine derivatives with active hydrogen
.Primary or secondary amine compounds having active hydrogen
・ Organic acids such as ammonia and carboxylic acids
・ Hydrogen halides such as hydrogen chloride
・ Alcohols and thiols
.Quaternary chlorinating agents that are hydrazine derivatives that do not have active hydrogen or a mixture of tertiary amine and acid
[0076]
Examples of the hydrazine derivative (C) having active hydrogen include the following.
(1) Carbohydrazide, propionic acid hydrazide, salicylic acid hydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, thiocarbohydrazide, 4,4'-oxybisbenzenesulfonylhydrazide, benzophenone hydrazone Hydrazide compounds such as;
(2) Pyrazole compounds such as pyrazole, 3,5-dimethylpyrazole, 3-methyl-5-pyrazolone, 3-amino-5-methylpyrazole;
[0077]
(3) 1,2,4-triazole, 3-amino-1,2,4-triazole, 4-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 5-amino -3-mercapto-1,2,4-triazole, 2,3-dihydro-3-oxo-1,2,4-triazole, 1H-benzotriazole, 1-hydroxybenzotriazole (monohydrate), 6- Triazole compounds such as methyl-8-hydroxytriazolopyridazine, 6-phenyl-8-hydroxytriazolopyridazine, 5-hydroxy-7-methyl-1,3,8-triazaindolizine;
[0078]
(4) Tetrazole compounds such as 5-phenyl-1,2,3,4-tetrazole and 5-mercapto-1-phenyl-1,2,3,4-tetrazole;
(5) Thiadiazole compounds such as 5-amino-2-mercapto-1,3,4-thiadiazole and 2,5-dimercapto-1,3,4-thiadiazole;
(6) Maleic hydrazide, 6-methyl-3-pyridazone, 4,5-dichloro-3-pyridazone, 4,5-dibromo-3-pyridazone, 6-methyl-4,5-dihydro-3-pyridazone, etc. Pyridazine compounds
[0079]
Of these, pyrazole compounds and triazole compounds having a 5-membered or 6-membered ring structure and having a nitrogen atom in the ring structure are particularly suitable.
These hydrazine derivatives can be used individually by 1 type or in mixture of 2 or more types.
[0080]
Typical examples of the amine compound having active hydrogen that can be used as part of the active hydrogen-containing compound (B) include the following.
(1) A primary amino group of an amine compound containing one secondary amino group and one or more primary amino groups, such as diethylenetriamine, hydroxyethylaminoethylamine, ethylaminoethylamine, methylaminopropylamine, A compound modified with aldimine, ketimine, oxazoline or imidazoline by heat reaction with aldehyde or carboxylic acid at a temperature of about 100 to 230 ° C., for example;
[0081]
(2) Secondary monoamines such as diethylamine, diethanolamine, di-n- or -iso-propanolamine, N-methylethanolamine, N-ethylethanolamine;
(3) Secondary amine-containing compound obtained by adding a monoalkanolamine such as monoethanolamine and dialkyl (meth) acrylamide by Michael addition reaction;
(4) A compound obtained by modifying the primary amino group of an alkanolamine such as monoethanolamine, neopentanolamine, 2-aminopropanol, 3-aminopropanol, 2-hydroxy-2 '(aminopropoxy) ethyl ether to ketimine;
[0082]
The quaternary chlorinating agent that can be used as a part of the active hydrogen-containing compound (B) is a hydrazine derivative or a tertiary amine that does not have active hydrogen and is not reactive with an epoxy group by itself. In order to be able to react with the acid. The quaternary chlorinating agent reacts with an epoxy group in the presence of water as necessary to form a quaternary salt with the epoxy group-containing resin.
[0083]
The acid used to obtain the quaternary chlorinating agent may be any of organic acids such as acetic acid and lactic acid, and inorganic acids such as hydrochloric acid. Examples of the hydrazine derivative having no active hydrogen used for obtaining a quaternary chlorinating agent include 3,6-dichloropyridazine, and examples of the tertiary amine include dimethylethanolamine, triethylamine, Examples include trimethylamine, triisopropylamine, and methyldiethanolamine.
[0084]
The reaction product (X) of the film-forming organic resin (A) and the active hydrogen-containing compound (B) composed of a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is used as the film-forming organic resin (A). And an active hydrogen-containing compound (B) are reacted at 10 to 300 ° C., preferably 50 to 150 ° C., for about 1 to 8 hours.
[0085]
This reaction may be performed by adding an organic solvent, and the type of the organic solvent to be used is not particularly limited. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, dibutyl ketone, cyclohexanone; ethanol, butanol, 2-ethylhexyl alcohol, benzyl alcohol, ethylene glycol, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether , Propylene glycol, propylene glycol monomethyl ether, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether and other alcohols and ethers containing hydroxyl groups; ethyl acetate, butyl acetate, ethylene glycol monobutyl ether acetate and other esters; toluene, xylene Aromatic hydrocarbons, etc. Indicates possible, it is possible to use one or more of these. Of these, ketone-based or ether-based solvents are particularly preferable from the viewpoints of solubility with an epoxy resin, film-forming properties, and the like.
[0086]
The blending ratio between the film-forming organic resin (A) and the active hydrogen-containing compound (B) composed of a hydrazine derivative (C) in which some or all of the compounds have active hydrogen is a solid content ratio. ) The active hydrogen-containing compound (B) is preferably 0.5 to 20 parts by weight, particularly preferably 1.0 to 10 parts by weight with respect to 100 parts by weight.
[0087]
When the film-forming organic resin (A) is an epoxy group-containing resin (D), the blending ratio of the epoxy group-containing resin (D) and the active hydrogen-containing compound (B) is the active hydrogen-containing compound (B ) And the number of epoxy groups in the epoxy group-containing resin (D) [number of active hydrogen groups / number of epoxy groups] is 0.01 to 10, more preferably 0.1 to 8, and still more preferably. It is appropriate to set it to 0.2-4 from points, such as corrosion resistance.
[0088]
The proportion of the hydrazine derivative (C) having active hydrogen in the active hydrogen-containing compound (B) is 10 to 100 mol%, more preferably 30 to 100 mol%, and still more preferably 40 to 100 mol%. Is appropriate. If the ratio of the hydrazine derivative (C) having active hydrogen is less than 10 mol%, the organic film cannot be provided with a sufficient rust prevention function, and the resulting rust prevention effect is obtained by simply mixing the film-forming organic resin and the hydrazine derivative. It is no different from the case of using it.
[0089]
In the present invention, in order to form a dense barrier film, it is desirable to mix a curing agent in the resin composition and heat cure the organic film.
As a curing method for forming a resin composition film, (1) a curing method using a urethanization reaction between an isocyanate and a hydroxyl group in a base resin, (2) 1 selected from melamine, urea and benzoguanamine An etherification reaction between an alkyl etherified amino resin obtained by reacting a monohydric alcohol having 1 to 5 carbon atoms with a part or all of a methylol compound obtained by reacting formaldehyde with a seed or more and a hydroxyl group in a base resin. The curing method to be used is suitable, and among these, it is particularly preferable to use a urethanization reaction between isocyanate and a hydroxyl group in the base resin as a main reaction.
[0090]
The polyisocyanate compound used in the curing method of (1) above is composed of an aliphatic, alicyclic (including heterocyclic) or aromatic isocyanate compound having at least two isocyanate groups in one molecule, or many of these compounds. It is a compound partially reacted with a monohydric alcohol. Examples of such polyisocyanate compounds include the following.
(1) m- or p-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate, o- or p-xylylene diisocyanate, hexamethylene diisocyanate, dimer acid diisocyanate, isophorone diisocyanate
[0091]
(2) Compound (1) above or a mixture thereof and polyhydric alcohols (dihydric alcohols such as ethylene glycol and propylene glycol; trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric alcohols such as pentaerythritol; A reaction product with a hexahydric alcohol such as sorbitol and dipentaerythritol), in which at least two isocyanates remain in one molecule
These polyisocyanate compounds can be used individually by 1 type or in mixture of 2 or more types.
[0092]
Moreover, as a protective agent (blocking agent) of a polyisocyanate compound, for example,
(1) Aliphatic monoalcohols such as methanol, ethanol, propanol, butanol and octyl alcohol
(2) Ethylene glycol and / or diethylene glycol monoethers such as methyl, ethyl, propyl (n-, iso), butyl (n-, iso, sec), etc.
(3) Aromatic alcohols such as phenol and cresol
(4) Oxime such as acetoxime and methyl ethyl ketone oxime
A polyisocyanate compound that is stably protected at least at room temperature can be obtained by reacting one or more of these with the polyisocyanate compound.
[0093]
Such a polyisocyanate compound (E) is (A) / (E) = 95/5 to 55/45 (weight ratio of non-volatile content) with respect to the film-forming organic resin (A) as a curing agent, preferably ( It is suitable to mix | blend in the ratio of A) / (E) = 90 / 10-65 / 35. The polyisocyanate compound has water absorption, and if it is blended exceeding (A) / (E) = 55/45, the adhesion of the organic film is deteriorated. Furthermore, when an overcoating is performed on the organic film, the unreacted polyisocyanate compound moves into the coating film, resulting in inhibition of curing of the coating film and poor adhesion. From such a viewpoint, the blending amount of the polyisocyanate compound (E) is preferably (A) / (E) = 55/45 or less.
[0094]
The film-forming organic resin (A) is sufficiently crosslinked by the addition of the crosslinking agent (curing agent) as described above, but it is desirable to use a known curing accelerating catalyst in order to further increase the low temperature crosslinking property. Examples of the curing accelerating catalyst include N-ethylmorpholine, dibutyltin dilaurate, cobalt naphthenate, stannous chloride, zinc naphthenate, and bismuth nitrate.
For example, when an epoxy group-containing resin is used for the film-forming organic resin (A), a known acrylic, alkyd, polyester, or the like is mixed with the epoxy group-containing resin for the purpose of improving some physical properties such as adhesion. It can also be used.
[0095]
  In the organic filmRust prevention additive component (Y) of any of the following (a) to (f) which is a self-repairing substance:
  (A) Ca ion exchange silica and phosphate
  (B) Ca ion exchange silica, phosphate and silicon oxide
  (C) Calcium compound and silicon oxide
  (D) calcium compounds, phosphates and silicon oxides
  (E) Molybdate
  (F) TriazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles and thiurams
Or the antirust addition component (Y) which mix | blended the other component with said (e) and / or (f) is added.
  The anticorrosion mechanism by these components (a) to (f) is as described above.
[0096]
The Ca ion exchange silica contained in the components (a) and (b) is obtained by fixing calcium ions on the surface of the porous silica gel powder, and Ca ions are released in a corrosive environment to form a precipitated film.
Any Ca ion-exchanged silica can be used, but those having an average particle size of 6 μm or less, preferably 4 μm or less are preferable, and for example, those having an average particle size of 2 to 4 μm can be used. When the average particle size of the Ca ion exchange silica exceeds 6 μm, the corrosion resistance is lowered and the dispersion stability in the coating composition is lowered.
[0097]
The Ca concentration in the Ca ion-exchanged silica is 1 wt% or more, desirably 2 to 8 wt%. When the Ca concentration is less than 1 wt%, the rust prevention effect due to Ca release cannot be sufficiently obtained. The surface area, pH, and oil absorption amount of the Ca ion exchange silica are not particularly limited.
[0098]
As the Ca ion exchange silica as described above, W.R.Grace & Co. SHIELDEX C303 (average particle size 2.5 to 3.5 μm, Ca concentration 3 wt%), SHIELDEX AC3 (average particle size 2.3 to 3.1 μm, Ca concentration 6 wt%), SHIELDEX AC5 (average particle size 3. 8 to 5.2 μm, Ca concentration 6 wt%), SHIELDEX (average particle diameter 3 μm, Ca concentration 6 to 8 wt%) manufactured by Fuji Silysia Chemical Ltd., SHIELDEX SY710 (average particle diameter 2.2 to 2.5 μm, Ca A concentration of 6.6 to 7.5 wt%) can be used.
[0099]
The phosphates contained in the components (a), (b), and (d) include all types of salts such as single salts and double salts. Moreover, there is no limitation in the metal cation which comprises it, and any metal cation, such as zinc phosphate, magnesium phosphate, calcium phosphate, and aluminum phosphate, may be used. Further, there is no limitation on the skeleton or the degree of condensation of phosphate ions, and any of normal salt, dihydrogen salt, monohydrogen salt or phosphite may be used. In addition to orthophosphate, the normal salt may be polyphosphate. Includes all condensed phosphates such as salts.
[0100]
  The calcium compound contained in the components (c) and (d) may be any of calcium oxide, calcium hydroxide, and calcium salt, and one or more of these can be used. In addition, there are no particular restrictions on the type of calcium salt. In addition to simple salts containing only calcium as a cation such as calcium silicate, calcium carbonate, and calcium phosphate, calcium and calcium such as calcium phosphate / zinc, calcium phosphate / magnesium, etc. Use double salts containing cations other thanMay be.
[0101]
The silicon oxide contained in the components (b), (c), and (d) may be colloidal silica or dry silica. When the colloidal silica is based on a water-based film-forming resin, for example, under the trade name, “Snowtex O”, “Snowtex N”, “Snowtex 20”, “Snowtex 30”, “Snowtex 40” manufactured by Nissan Chemical Industries, Ltd. SNOWTEX C, SNOWTEX S, Cataloid S, Cataloid SI-350, Cataloid SI-40, Cataloid SA, Cataloid SN, Adelite AT-20-50 manufactured by Asahi Denka Kogyo Co., Ltd. Adelite AT-20N, Adelite AT-300, Adelite AT-300S, Adelite AT20Q, etc. can be used.
[0102]
In addition, when the solvent-based film forming resin is used as a base, for example, under the trade name, the product is manufactured by Nissan Chemical Industries, Ltd., organosilica sol MA-ST-M, organosilica sol IPA-ST, organosilica sol EG-ST, organosilica sol E-ST-ZL, organosilica sol NPC-ST, organosilica sol DMAC-ST, organosilica sol DMAC-ST-ZL, organosilica sol XBA-ST, organosilica sol MIBK-ST, OSCAL-1132 manufactured by Catalyst Kasei Kogyo Co., Ltd. OSCAL-1232, OSCAL-1332, OSCAL-1432, OSCAL-1532, OSCAL-1632, OSCAL-1722, or the like can be used.
[0103]
In particular, the organic solvent-dispersed silica sol is excellent in dispersibility and superior in corrosion resistance than fumed silica.
Examples of fumed silica include AEROSIL R971, AEROSIL R812, AEROSIL R811, AEROSIL R974, AEROSIL R202, AEROSIL R805, AEROSIL 130, AEROSIL 200, AEROSIL 300, and AEROSIL 300 manufactured by Nippon Aerosil Co., Ltd. Can be used.
[0104]
The fine-particle silica contributes to the formation of a dense and stable zinc corrosion product in a corrosive environment, and the corrosion product is considered to be able to suppress the promotion of corrosion by being densely formed on the plating surface. It has been.
From the viewpoint of corrosion resistance, it is preferable to use fine silica particles having a particle diameter of 5 to 50 nm, desirably 5 to 20 nm, more preferably 5 to 15 nm.
[0105]
The molybdate of component (e) is not limited in its skeleton and degree of condensation, and examples thereof include orthomolybdate, paramolybdate, and metamolybdate. Moreover, all salts, such as a single salt and a double salt, are included, and phosphoric acid molybdate etc. are mentioned as a double salt.
[0106]
  Among the organic compounds of the component (f), triazoles include 1,2,4-triazole, 3-amino-1,2,4-triazole, 3-mercapto-1,2,4-triazole, 5- Amino-3-mercapto-1,2,4-triazole, 1H-benzotriazoleEtc.Examples of thiadiazoles include 5-amino-2-mercapto-1,3,4-thiadiazole, 2,5-dimercapto-1,3,4-thiadiazole, and examples of thiazoles include 2-N, N-diethyl. Examples thereof include thiobenzothiazole and 2-mercaptobenzothiazole, and examples of thiurams include tetraethylthiuram disulfide.
[0111]
  As described above, the rust preventive additive components (a) to (f) have a precipitation effect (in the case of components (a) to (d)) and a passivation effect (component (e) in the corrosive environment as described above. ) And a protective film are formed respectively by the adsorption effect (in the case of component (f)).
  In particular,By blending any of the above components (a) to (f) with a specific chelate forming resin that is a base resin, the barrier effect by the chelate forming resin and the self-repairing effect by the above components (a) to (f) are obtained. By combining it, an extremely excellent anticorrosive effect is exhibited.
[0112]
  Further, from the self-repair effect (the above-described three types of protective film forming effects) obtained by the components (a) to (d), (e), and (f), a higher level of self-repairability is achieved. In order to obtain, it is preferable to adjust (blend) the anticorrosive additive component (Y) having the following combination in which other components are added to (e) and / or (f).(Five) as well as (6)In this case, the highest degree of self-repairability (that is, white rust resistance) can be obtained.
(1) (e) Molybdate, (g)Calcium compoundsAnd (h) a rust-preventing additive component containing phosphate and / or silicon oxide
[0113]
(2)
(F) TriazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles, thiurams, (g)Calcium compoundsAnd (h) a rust-preventing additive component containing phosphate and / or silicon oxide
(3)
(F) TriazoleKind, chiaRust-preventing additive component containing one or more organic compounds selected from diazoles, thiazoles, thiurams, and (i) Ca ion exchange silica
(Four)
(E) molybdate and (f) triazoleKind, chiaRust preventive additive containing one or more organic compounds selected from diazoles, thiazoles and thiurams
[0114]
(Five)
(E) molybdate, (f) triazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles, thiurams, (g)Calcium compoundsAnd (h) a rust-preventing additive component containing phosphate and / or silicon oxide
(6)
(E) molybdate, (f) triazoleKind, chiaRust-preventing additive component containing one or more organic compounds selected from diazoles, thiazoles, thiurams, and (i) Ca ion exchange silica
  Here, applicable calcium compounds, phosphates, silicon oxides, and Ca ion exchange silicas are the same as those described above for the components (a) to (d).
[0115]
  (E) molybdate of (1) above, (g)Calcium compounds, And (h) In the anti-rust additive component containing phosphate and / or silicon oxide, the mixing ratio of these (e), (g) and (h) is the weight ratio of solids (e) / ( g) + (h) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and (g) / (h) = 1. / 99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20.
[0116]
Here, when (e) / (g) + (h) is less than 1/99 or more than 99/1, the effect of combining different self-repair effects cannot be sufficiently obtained. Also, if (g) / (h) is less than 1/99, the amount of calcium elution is small, and a protective film that only blocks the corrosion starting point cannot be formed. On the other hand, if it exceeds 99/1, it is necessary for forming a protective film. Not only does the above amount of calcium elute, but also the phosphate ions necessary to cause a complex formation reaction with the calcium and the silicon oxide necessary to adsorb calcium are not sufficiently supplied, so sufficient self-repair effect Cannot be obtained.
[0118]
  the above(2)(F) TriazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles, thiurams, (g)Calcium compounds, And (h) In the anti-rust additive component containing phosphate and / or silicon oxide, the mixing ratio of (f), (g) and (h) is the weight ratio of solid content (f) / ( g) + (h) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and (g) / (h) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20 is appropriate.
[0119]
Here, when (f) / (g) + (h) is less than 1/99 or more than 99/1, the effect of combining different self-repair effects cannot be sufficiently obtained. Also, if (g) / (h) is less than 1/99, the amount of calcium elution is small, and a protective film that only blocks the corrosion starting point cannot be formed. On the other hand, if it exceeds 99/1, it is necessary for forming a protective film. Not only does the above amount of calcium elute, but also the phosphate ions necessary to cause a complex formation reaction with the calcium and the silicon oxide necessary to adsorb calcium are not sufficiently supplied, so sufficient self-repair effect Cannot be obtained.
[0120]
  the above(3)(F) TriazoleKind, chiaIn the anti-rust additive component containing one or more organic compounds selected from diazoles, thiazoles and thiurams and (i) Ca ion exchange silica, the mixing ratio of (f) and (i) is the solid content (F) / (i) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20.
  Here, when (f) / (i) is less than 1/99 or more than 99/1, the effect of combining different self-repair effects cannot be sufficiently obtained.
[0121]
  the above(Four)(E) molybdate and (f) triazoleKind, chiaIn the anticorrosive additive component containing one or more organic compounds selected from diazoles, thiazoles, and thiurams, the mixing ratio of (e) and (f) is the weight ratio of (e) / (F) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20.
  Here, when (e) / (f) is less than 1/99 or more than 99/1, the effect by combining different self-repair effects cannot be sufficiently obtained.
[0122]
  the above(Five)(E) molybdate, (f) triazoleKind, chiaOne or more organic compounds selected from diazoles, thiazoles, thiurams, (g)Calcium compounds, And (h) In the anti-rust additive component containing phosphate and / or silicon oxide, the mixing ratio of these (e), (f), (g) and (h) is the weight ratio of solids ( e) / (f) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and (e) / (g) + (h ) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and (f) / (g) + (h) = 1/99 ~ 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20, (g) / (h) = 1/99 to 99/1, preferably 10 / 90-90 / 10, more preferably 20 / 80-80 / 20 is suitable.
[0123]
Here, when (e) / (f), (e) / (g) + (h), (f) / (g) + (h) are less than 1/99 or more than 99/1, respectively, different self The effect of combining repair effects cannot be obtained sufficiently. Also, if (g) / (h) is less than 1/99, the amount of calcium elution is small, and a protective film that only blocks the corrosion starting point cannot be formed. On the other hand, if it exceeds 99/1, it is necessary for forming a protective film. Not only does the above amount of calcium elute, but also the phosphate ions necessary to cause a complex formation reaction with the calcium and the silicon oxide necessary to adsorb calcium are not sufficiently supplied, so sufficient self-repair effect Cannot be obtained.
[0124]
  the above(6)(E) molybdate, (f) triazoleKind, chiaIn the anticorrosive additive component containing one or more organic compounds selected from diazoles, thiazoles and thiurams, and (i) Ca ion-exchanged silica, these (e), (f) and (i) The mixing ratio of (e) / (f) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20 in terms of the weight ratio of the solid content. (E) / (i) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20, and (f) / (i) = 1/99 to 99/1, preferably 10/90 to 90/10, more preferably 20/80 to 80/20 is appropriate.
  Here, when (e) / (f), (e) / (i), and (f) / (i) are less than 1/99 or more than 99/1, the effect of combining different self-repair effects Is not enough.
[0125]
  Compounding amount of the above rust preventive additive (Y) in the organic resin film(Composite additionThe total blending amount of the self-repairing substances produced is a reaction product (X) that is a resin composition for film formation (hydrazine in which the film-forming organic resin (A) and a part or all of the compounds have active hydrogen. 1 to 100 parts by weight (solid content), preferably 5 to 80 parts by weight (solid content) with respect to 100 parts by weight (solid content) of reaction product with active hydrogen-containing compound (B) comprising derivative (C) ), More preferably 10 to 50 parts by weight (solid content). When the blending amount of the antirust additive component (Y) is less than 1 part by weight, the effect of improving corrosion resistance is small. On the other hand, if the blending amount exceeds 100 parts by weight, the corrosion resistance decreases, which is not preferable.
[0126]
In addition to the above rust preventive additives, the organic film contains other oxide fine particles (eg, aluminum oxide, zirconium oxide, titanium oxide, cerium oxide, antimony oxide), phosphomolybdic acid as a corrosion inhibitor. Salts (for example, aluminum phosphomolybdate), organic phosphoric acid and its salts (for example, phytic acid, phytate, phosphonic acid, phosphonate, and metal salts thereof, alkali metal salts, alkaline earth metal salts, etc.) ), Organic inhibitors (for example, hydrazine derivatives, thiol compounds, dithiocarbamates, etc.) can be added.
[0127]
  If necessary, a solid lubricant (Z) can be blended in the organic film for the purpose of improving the workability of the film.
  Examples of the solid lubricant (Z) that can be applied to the present invention include the following, and one or more of these may be used.it can.
(1) Polyolefin wax, paraffin wax: For example, polyethylene wax, synthetic paraffin, natural paraffin, micro wax, chlorinated hydrocarbon, etc.
(2) Fluorine resin fine particles: For example, polyfluoroethylene resin (polytetrafluoroethylene resin, etc.), polyvinyl fluoride resin, polyvinylidene fluoride resin, etc.
[0128]
In addition, fatty acid amide compounds (eg, stearic acid amide, palmitic acid amide, methylene bis stearoamide, ethylene bis stearoamide, oleic acid amide, esylic acid amide, alkylene bis fatty acid amide), metal Soaps (eg, calcium stearate, lead stearate, calcium laurate, calcium palmitate, etc.), metal sulfides (eg, molybdenum disulfide, tungsten disulfide, etc.), graphite, graphite fluoride, boron nitride, polyalkylene glycol, You may use 1 type, or 2 or more types, such as an alkali metal sulfate.
[0129]
Among the above solid lubricants, polyethylene wax and fluororesin fine particles (in particular, polytetrafluoroethylene resin fine particles) are preferable.
Examples of the polyethylene wax include Celestus 9615A, Celidust 3715, Celidust 3620, Celidust 3910, Sunwax 131-P manufactured by Sanyo Chemical Co., Ltd., Sunwax 161-P, manufactured by Mitsui Petrochemical Co., Ltd. Chemipearl W-100, Chemipearl W-200, Chemipearl W-500, Chemipearl W-800, Chemipearl W-950 and the like can be used.
[0130]
The fluororesin fine particles are most preferably tetrafluoroethylene fine particles. For example, Lubron L-2 and Lubron L-5 manufactured by Daikin Industries, Ltd., MP1100 and MP1200 manufactured by Mitsui DuPont Co., Ltd., Asahi IC Co., Ltd. Fluoropolymers Co., Ltd. full-on dispersion AD1, full-on dispersion AD2, full-on L141J, full-on L150J, full-on L155J, etc. are suitable.
Among these, a particularly excellent lubricating effect can be expected by the combined use of polyolefin wax and tetrafluoroethylene fine particles.
[0131]
The blending amount of the solid lubricant (Z) in the organic film is such that the reaction product (X), which is a resin composition for film formation (the film-forming organic resin (A) and some or all of the compounds contain active hydrogen). 1 to 80 parts by weight (solid content), preferably 3 to 40 parts by weight (reaction product with active hydrogen-containing compound (B) comprising hydrazine derivative (C)) Solid content). When the blending amount of the solid lubricant (Z) is less than 1 part by weight, the lubricating effect is poor. On the other hand, when the blending amount exceeds 80 parts by weight, the paintability is unfavorable.
[0132]
  The organic film of the organic coated steel sheet of the present invention is usually a reaction between the film-forming organic resin (A) and an active hydrogen-containing compound (B) composed of a hydrazine derivative (C) in which some or all of the compounds have active hydrogen. The product (X) (resin composition) is the main component, and this is a self-repairing substance.Certain ingredientsThe compounded rust preventive additive component (Y) is blended, and if necessary, a solid lubricant (Z), a curing agent, and the like are added, but if necessary, an organic coloring pigment (for example, , Condensed polycyclic organic pigments, phthalocyanine organic pigments, etc.), colored dyes (eg, organic solvent-soluble azo dyes, water-soluble azo metal dyes, etc.), inorganic pigments (eg, titanium oxide), chelating agents (eg, , Thiols, etc.), conductive pigments (eg, metal powders such as zinc, aluminum, nickel, iron phosphide, antimony-doped tin oxide, etc.), coupling agents (eg, silane coupling agents, titanium coupling agents, etc.) 1 type, or 2 or more types, such as a melamine cyanuric acid adduct, can be added.
[0133]
Moreover, the coating composition for film formation containing the said main component and an additional component normally contains a solvent (an organic solvent and / or water), and also a neutralizer etc. are added as needed.
The organic solvent is not particularly limited as long as it can dissolve or disperse the reaction product (X) of the film-forming organic resin (A) and the active hydrogen-containing compound (B) and can be prepared as a coating composition. For example, various organic solvents exemplified above can be used.
The neutralizing agent is blended as necessary to neutralize the film-forming organic resin (A) to make it water-based. When the film-forming organic resin (A) is a cationic resin, Acids such as acetic acid, lactic acid and formic acid can be used as a neutralizing agent.
[0134]
The organic film as described above is formed on the composite oxide film.
The dry film thickness of the organic film is 0.1 to 5 μm, preferably 0.3 to 3 μm, and more preferably 0.5 to 2 μm. When the film thickness of the organic film is less than 0.1 μm, the corrosion resistance is insufficient. On the other hand, when the film thickness exceeds 5 μm, the conductivity and workability deteriorate.
In addition, when it is desired to obtain high conductivity and spot weldability as well as corrosion resistance, the adhesion amount of the organic film is 0.1 g / m.²Or more, 0.5 g / m²Less, preferably 0.15 g / m²Or more, 0.5 g / m²It is appropriate to make it less than. Organic film adhesion is 0.1 g / m²If it is less than 1, the corrosion resistance is insufficient, while the adhesion amount is 0.5 g / m.²As described above, desired extremely high conductivity and spot weldability cannot be obtained.
[0135]
On the surface of the galvanized steel sheet, No. 2 in Table 2 and Table 3. A composite oxide film (component (α) and P) satisfying the conditions of the present invention comprising the first layer film composition₂O₅Total adhesion amount of component (β) in converted amount and component (γ) in metal converted amount of Mg, Mn and Al: 359 mg / m²No. 4 in Table 4 is formed on the upper part. No. 1 in Table 5 with respect to 100 parts by weight of the solid content of the resin composition for second layer coating (base resin: thermosetting epoxy resin). FIG. 1 shows the result of investigating the relationship between the adhesion amount of the organic film and the corrosion resistance of an organic coated steel sheet formed with an organic film composed of a coating composition containing 15 parts by weight of 15 rust preventive additives. FIG. 2 shows the result of examining the relationship between the adhesion amount of the film and spot weldability, and FIG. 3 shows the result of examining the relationship between the adhesion amount of the organic film and the conductivity.
In addition, the corrosion resistance is the same evaluation standard as [Example 1] based on the white rust occurrence area ratio after 20 cycles after performing a composite corrosion test (CCT) in which the white rust resistance is evaluated in [Example 1]. evaluated. Moreover, about the spot weldability and electroconductivity, the test similar to [Example 2] was done, and the same evaluation criteria evaluated.
[0136]
  According to FIG. 1, the adhesion amount of the organic film increases.Corrosion resistanceThe adhesion is improved and the adhesion amount is 0.1 g / m.²Or more, preferably 0.15 g / m²It turns out that favorable corrosion resistance is acquired by setting it as the above. On the other hand, according to FIG. 2, the adhesion amount of the organic film is 0.5 g / m.²If it becomes above, spot weldability (spot continuous spotting property) will fall rapidly, and according to FIG. 3, the adhesion amount of an organic film is 0.5 g / m.²It can be seen that the conductivity also deteriorates sharply when the above is reached. For the above reasons, in order to obtain excellent corrosion resistance and particularly high conductivity and spot weldability, the amount of organic coating deposited is 0.1 g / m.²Or more, 0.5 g / m²Less, preferably 0.15 g / m²Or more, 0.5 g / m²It is appropriate to make it less than.
[0137]
  Next, the manufacturing method of the organic coating steel plate of this invention is demonstrated.
  The organic-coated steel sheet of the present invention is obtained by treating the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet with a treatment liquid containing the components of the composite oxide film described above (coating a treatment liquid), and then drying by heating, The upper layer contains a reaction product (X) of the above-described film-forming organic resin (A) and an active hydrogen-containing compound (B) composed of a hydrazine derivative (C) in which some or all of the compounds have active hydrogen (preferably Is the main component),To this specific ingredientsIt is manufactured by applying a coating composition to which the compositely added rust preventive additive component (Y) is added, and further adding a solid lubricant (Z) as necessary, and then drying by heating.
  In addition, the surface of the plated steel sheet can be subjected to an alkali degreasing treatment as necessary before applying the treatment liquid, and further subjected to a pretreatment such as a surface adjustment treatment in order to improve adhesion and corrosion resistance.
[0138]
To form a composite oxide film by treating the surface of a zinc-based plated steel sheet or aluminum-based plated steel sheet with a treatment liquid,
(A) oxide fine particles;
(B) phosphoric acid and / or a phosphoric acid compound;
(C) Metal ions of any one of Mg, Mn, and Al, water-soluble ions containing at least one of the metals, compounds containing at least one of the metals, and at least one of the metals One or more selected from the group consisting of complex compounds including species;
And, if necessary, treated with a treatment liquid (aqueous solution) to which each of the above-described additive components (organic resin component, iron group metal ion, corrosion inhibitor, other additives) is added, and then dried by heating. It is preferable.
[0139]
  Here, as the treatment liquid, the molar concentration of the additive component (I), the additive component (B)P ₂ O ₅ The total molar concentration in terms of conversion and the total molar concentration in terms of metal amount of the metal of the additive component (c) are molar ratio (ii) / (iii) = 0.1-20, preferably 0.1-10 mol. A treatment liquid adjusted to satisfy the ratio (c) / (b) = 0.1 to 1.5 is used.
  When the molar ratio (A) / (C) is less than 0.1, the effect of adding oxide fine particles cannot be sufficiently obtained. On the other hand, when the molar ratio (I) / (C) exceeds 20, the oxide fine particles inhibit the densification of the film.
  If the molar ratio (c) / (b) is less than 0.1, the effect of adding metal components such as Mg cannot be sufficiently obtained. End up.
[0140]
  As oxide fine particles as additive component (a), silicon oxide (SiO ₂ Fine particles) are most preferred. The silicon oxide may be any water-dispersible silica fine particles that are stable in the treatment liquid, and commercially available silica sol, water-dispersible silicic acid oligomer, and the like can be used. However, since fluorides such as hexafluorosilicic acid are highly corrosive and have a great influence on the human body, it is desirable not to use them from the viewpoint of influence on the working environment.
  Amount of oxide fine particles added in the treatment liquid (in the case of silicon oxideSiO ₂ The addition amount as an amount) is 0.001-3.0 mol / L, preferably 0.05-1.0 mol / L, more preferably 0.1-0.5 mol / L. is there. When the addition amount of the oxide fine particles is less than 0.001 mol / L, the effect of the addition is not sufficient, and the corrosion resistance tends to be inferior. On the other hand, when the addition amount exceeds 3.0 mol / L, the water resistance of the film is deteriorated, and as a result, the corrosion resistance tends to deteriorate.
[0141]
  Examples of the phosphoric acid and / or phosphoric acid compound that is the additive component (b) include polyphosphoric acid such as orthophosphoric acid, pyrophosphoric acid, and tripolyphosphoric acid, metaphosphoric acid, and inorganic salts thereof (for example, primary aluminum phosphate), Forms in which phosphoric acid-containing compounds such as phosphoric acid, phosphite, hypophosphorous acid, hypophosphite and the like are present as complex ions with anions or metal cations generated when dissolved in an aqueous solution , Including the form existing as a free acid, the form existing in an aqueous dispersion as an inorganic salt, etc., and the amount of the phosphoric acid component in the present invention is the sum of all these forms present in the treatment liquid.P ₂ O ₅ It is specified as conversion.
[0142]
  The amount of phosphoric acid and / or phosphoric acid compound added in the treatment solution isP ₂ O ₅ 0.001 to 6.0 mol / L in terms of conversion, preferably 0.02 to 1.0 mol / L, more preferably 0.1 to 0.8 mol / L. If the addition amount of phosphoric acid and / or phosphoric acid compound is less than 0.001 mol / L, the effect of addition is not sufficient, and the corrosion resistance tends to be inferior. On the other hand, when the addition amount exceeds 6.0 mol / L, excess phosphate ions react with the plating film in a wet environment, and depending on the corrosive environment, the corrosion of the plating base is promoted, causing discoloration and spot-like rust generation. Become.
  Further, as the additive component (b), it is effective to use an ammonium phosphate salt because a composite oxide having excellent corrosion resistance can be obtained. As an ammonium phosphate salt, it is preferable to use 1 type (s) or 2 or more types, such as primary ammonium phosphate and secondary ammonium phosphate.
[0143]
The presence form of the additive component (c) in the treatment liquid may be a compound or a complex compound, but in order to obtain particularly excellent corrosion resistance, Mg, Mn, Al metal ions or Mg, Mn, Al metals are included. The form of water-soluble ions is particularly preferred.
In order to supply the ions of the additive component (c) as a metal salt, anions such as chlorine ions, nitrate ions, sulfate ions, acetate ions, borate ions may be added to the treatment liquid. In the present invention, the amounts of Mg, Mn, and Al components define the total of all these forms present in the processing liquid as metal amount conversion.
The addition amount of the additive component (c) in the treatment liquid is 0.001-3.0 mol / L in total in terms of metal amount, preferably 0.01-0.5 mol / L. It is. If the total addition amount is less than 0.001 mol, the effect of addition cannot be sufficiently obtained. On the other hand, if the addition amount exceeds 3.0 mol / L, these components adversely inhibit the network of the film. It becomes difficult to form a dense film. In addition, the metal component tends to be eluted from the film, and defects such as discoloration of the appearance occur depending on the environment.
[0144]
In the treatment liquid, the additive component (d) is further selected from the group consisting of a metal ion of any one of Ni, Fe and Co, and a water-soluble ion containing at least one of the above metals. An appropriate amount of seeds or more can be added, and by adding such an iron group metal, the blackening phenomenon caused by corrosion of the outermost plating layer in a wet environment, which occurs when no iron group metal is added, can be avoided. . Among these iron group metals, the effect of Ni is particularly high, and an excellent effect is observed even in a small amount. However, excessive addition of iron group metals such as Ni and Co leads to deterioration of corrosion resistance, so an appropriate amount must be added.
[0145]
The addition amount of the additive component (d) is in the range of 1/10000 to 1 mol, desirably 1/10000 to 1/100 mol, in terms of metal amount, per 1 mol of additive component (c) in terms of metal amount. It is preferable that If the addition amount of the additive component (d) is less than 1/10000 mol with respect to 1 mol of the additive component (c), the effect of the addition is not sufficient. To do.
In addition to the above-described additive components (a) to (d), an appropriate amount of the additive component to the film described above may be added to the treatment liquid.
The pH of the treatment liquid (aqueous solution) is 0.5-5, preferably 2-4. If the treatment liquid is less than pH 0.5, the reactivity of the treatment liquid becomes too high, so fine defects are formed in the film, and the corrosion resistance is lowered. On the other hand, when the treatment liquid exceeds pH 5, the reactivity of the treatment liquid becomes low, and the bonding at the interface between the plating film and the composite oxide film becomes insufficient, and in this case also, the corrosion resistance tends to decrease.
[0146]
As a method of coating the treatment liquid on the surface of the plated steel sheet, any of a coating method, a dipping method, and a spray method may be used. In the coating method, any of a roll coater (three roll method, two roll method, etc.) The application means may be used. In addition, after the coating process, dipping process, and spraying process using a squeeze coater, the coating amount can be adjusted, the appearance can be made uniform, and the film thickness can be made uniform by an air knife method or a roll drawing method.
Although there is no special restriction | limiting in the temperature of a process liquid, Room temperature-about 60 degreeC is suitable. Below room temperature, equipment for cooling is required, which is uneconomical. On the other hand, when the temperature exceeds 60 ° C., the water tends to evaporate, making it difficult to manage the treatment liquid.
[0147]
After coating the treatment liquid as described above, it is usually heat-dried without washing with water, but the treatment liquid used in the present invention forms a poorly soluble salt by reaction with the base plating steel plate, so that it is washed with water after treatment. You may go.
A method of heating and drying the coated treatment liquid is arbitrary, and for example, means such as a dryer, a hot air furnace, a high-frequency induction heating furnace, an infrared furnace can be used.
This heat drying treatment is preferably performed in the range of 50 to 300 ° C., desirably 80 to 200 ° C., more desirably 80 to 160 ° C. at the ultimate plate temperature. If the heating and drying temperature is less than 50 ° C., a large amount of moisture remains in the film, resulting in insufficient corrosion resistance. On the other hand, when the heating and drying temperature exceeds 300 ° C., not only is it uneconomical, but defects are easily generated in the film, and the corrosion resistance is lowered.
[0148]
After forming a composite oxide film on the surface of a zinc-based plated steel sheet or an aluminum-based plated steel sheet as described above, a coating composition for forming an organic film is applied to the upper layer. As a method for applying the coating composition, any method such as an application method, a dipping method, or a spray method can be employed. As a coating method, any method such as a roll coater (3-roll method, 2-roll method, etc.), a squeeze coater, or a die coater may be used. In addition, after the coating process, dipping process or spraying process using a squeeze coater or the like, the coating amount can be adjusted, the appearance can be made uniform, and the film thickness can be made uniform by an air knife method or a roll drawing method.
[0149]
After application of the coating composition, drying is usually performed without washing with water, but a washing process may be performed after application of the coating composition.
For the heat drying treatment, a dryer, a hot air furnace, a high-frequency induction heating furnace, an infrared furnace, or the like can be used. The heat treatment is desirably performed in the range of 50 to 350 ° C., preferably 80 to 250 ° C., at the ultimate plate temperature. When the heating temperature is less than 50 ° C., a large amount of moisture remains in the film, resulting in insufficient corrosion resistance. Further, when the heating temperature exceeds 350 ° C., not only is it uneconomical, but there is a possibility that defects occur in the film and the corrosion resistance is lowered.
[0150]
The present invention includes a steel plate having a coating as described above on both sides or one side. Accordingly, examples of the form of the steel sheet of the present invention include the following.
(1) Single side: plating film-complex oxide film-organic film, single side: plating film
(2) One side: plating film-complex oxide film-organic film, one side: plating film-known phosphating film
(3) Both sides: plating film-composite oxide film-organic film
(4) One side: plating film-complex oxide film-organic film, one side: plating film-complex oxide film
(5) One side: plating film-complex oxide film-organic film, one side: plating film-organic film
[0151]
【Example】
[Example 1]
The treatment liquid (film composition) for forming the first layer film shown in Tables 2 and 3 was prepared.
Moreover, the resin composition (reaction product) for forming the second layer film was synthesized as follows.
[Synthesis Example 1]
EP828 (manufactured by Yuka Shell Epoxy, Epoxy Equivalent 187), 1870 parts of bisphenol A, 2 parts of tetraethylammonium bromide and 300 parts of methyl isobutyl ketone are charged into a four-necked flask and heated to 140 ° C. and reacted for 4 hours. An epoxy resin having an epoxy equivalent of 1391 and a solid content of 90% was obtained. To this product, 1500 parts of ethylene glycol monobutyl ether was added and cooled to 100 ° C., 96 parts of 3,5-dimethylpyrazole (molecular weight 96) and 129 parts of dibutylamine (molecular weight 129) were added, and the epoxy group disappeared. After reacting for 6 hours, 205 parts of methyl isobutyl ketone was added while cooling to obtain a pyrazole-modified epoxy resin having a solid content of 60%. This is designated as resin composition (1). This resin composition (1) is a reaction product of a film-forming organic resin (A) and an active hydrogen-containing compound containing 50 mol% of a hydrazine derivative (C) having active hydrogen.
[0152]
[Synthesis Example 2]
4000 parts of EP1007 (manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 2000) and 2239 parts of ethylene glycol monobutyl ether were charged into a four-necked flask and heated to 120 ° C. to completely dissolve the epoxy resin in 1 hour. This was cooled to 100 ° C., 168 parts of 3-amino-1,2,4-triazole (molecular weight 84) was added, and the mixture was allowed to react for 6 hours until the epoxy group disappeared. A triazole-modified epoxy resin having a solid content of 60% was obtained. This is designated as resin composition (2). This resin composition (2) is a reaction product of a film-forming organic resin (A) and an active hydrogen-containing compound containing 100 mol% of a hydrazine derivative (C) having active hydrogen.
[0153]
[Synthesis Example 3]
222 parts of isophorone diisocyanate (isocyanate equivalent 111) and 34 parts of methyl isobutyl ketone were charged into a four-necked flask and maintained at 30 to 40 ° C., and 87 parts of methyl ethyl ketoxime (molecular weight 87) was added dropwise over 3 hours. By maintaining the time, a partially blocked isocyanate having an isocyanate equivalent of 309 and a solid content of 90% was obtained.
[0154]
Subsequently, 1428 parts of EP828 (manufactured by Yuka Shell Epoxy Co., Ltd., epoxy equivalent 187), 684 parts of bisphenol A, 1 part of tetraethylammonium bromide and 241 parts of methyl isobutyl ketone were charged into a four-necked flask and heated to 140 ° C. for 4 hours. Reaction was performed to obtain an epoxy resin having an epoxy equivalent of 1090 and a solid content of 90%. To this, 1000 parts of methyl isobutyl ketone was added and then cooled to 100 ° C., and 202 parts of 3-mercapto-1,2,4-triazole (molecular weight 101) was added and reacted for 6 hours until the epoxy group disappeared. Thereafter, 230 parts of the partially blocked isocyanate having a solid content of 90% was added and reacted at 100 ° C. for 3 hours to confirm that the isocyanate group had disappeared. Further, 461 parts of ethylene glycol monobutyl ether was added to obtain a triazole-modified epoxy resin having a solid content of 60%. This is designated as resin composition (3). This resin composition (3) is a reaction product of a film-forming organic resin (A) and an active hydrogen-containing compound containing 100 mol% of a hydrazine derivative (C) having active hydrogen.
[0155]
[Synthesis Example 4]
EP828 (manufactured by Yuka Shell Epoxy Co., Epoxy Equivalent 187) 1870 parts, bisphenol A 912 parts, tetraethylammonium bromide 2 parts, methyl isobutyl ketone 300 parts are charged into a four-necked flask and heated to 140 ° C. and reacted for 4 hours. An epoxy resin having an epoxy equivalent of 1391 and a solid content of 90% was obtained. To this was added 1500 parts of ethylene glycol monobutyl ether, cooled to 100 ° C., added with 258 parts of dibutylamine (molecular weight 129), reacted for 6 hours until the epoxy group disappeared, and then cooled with methyl isobutyl. 225 parts of ketone was added to obtain an epoxyamine adduct having a solid content of 60%. This is designated as resin composition (4). This resin composition (4) is a reaction product of a film-forming organic resin (A) and an active hydrogen-containing compound that does not contain a hydrazine derivative (C) having active hydrogen.
[0156]
  Curing agents were blended in the resin compositions (1) to (4) synthesized as described above to prepare resin compositions (coating compositions) shown in Table 4. These coating compositions includeTable 5A rust preventive additive component (self-repairing substance) and a solid lubricant shown in Table 6 were appropriately blended and dispersed for a required time using a coating disperser (sand grinder) to obtain a desired coating composition.
[0157]
In order to obtain organic coated steel sheets for home appliances, building materials, and automobile parts, Table 1 shows various zinc-based plating or aluminum-based plating applied to cold-rolled steel sheets having a thickness of 0.8 mm and a surface roughness Ra of 1.0 μm. After using the plated steel plate as the treated original plate, the surface of the plated steel plate was subjected to alkaline degreasing treatment, water-washing and drying, and then the treatment liquids (film compositions) shown in Tables 2 and 3 were applied with a roll coater and dried by heating. A layer film was formed. The film thickness of the first layer film was adjusted by the solid content (heating residue) of the treatment liquid or coating conditions (rolling force of the roll, rotational speed, etc.). Subsequently, the coating composition shown in Table 4 was applied by a roll coater and heated and dried to form a second layer film, thereby producing organic coated steel sheets of Examples of the present invention and Comparative examples. The film thickness of the second layer film was adjusted by the solid content (heating residue) of the coating composition or the coating conditions (roll rolling force, rotational speed, etc.).
[0158]
The obtained organic coated steel sheet was evaluated for quality performance (film appearance, white rust resistance, white rust resistance after alkali degreasing, paint adhesion, workability). The results are shown in Tables 7 to 39 together with the film configurations of the first layer film and the second layer film.
Evaluation of the quality performance of the organic coated steel sheet was performed as follows.
[0159]
(1) Film appearance
About each sample, the uniformity (existence of unevenness) of the film | membrane external appearance was evaluated visually. The evaluation criteria are as follows.
○: Uniform appearance with no unevenness
Δ: Appearance in which unevenness is slightly noticeable
X: Appearance with noticeable unevenness
[0160]
(2) White rust resistance
The composite corrosion test (CCT) shown below was performed for each sample, and the white rust generation area ratio after a predetermined cycle was evaluated.
[Details of one cycle of composite corrosion test (CCT)]
3 wt% salt spray test (30 ° C; 0.5 hour)
↓
Wetting test (30 ° C., 95% RH; 1.5 hours)
↓
Hot air drying test (50 ° C., 20% RH; 2.0 hours)
↓
Hot air drying test (30 ° C., 20% RH; 2.0 hours)
The evaluation criteria are as follows.
◎: No white rust
○ +: White rust generation area ratio less than 5%
○: White rust generation area ratio 5% or more, less than 10%
○-: White rust area ratio of 10% or more and less than 25%
Δ: White rust generation area ratio 25% or more, less than 50%
X: White rust generation area ratio 50% or more
[0161]
(3) White rust resistance after alkaline degreasing
About each sample, after carrying out alkali degreasing with the alkali treatment liquid CLN-364S (60 degreeC, spray 2 minutes) by Nippon Parkerizing Co., Ltd., said composite corrosion test (CCT) is performed, and the white rust after a predetermined cycle The area ratio was evaluated. The evaluation criteria are as follows.
◎: No white rust
○ +: White rust generation area ratio less than 5%
○: White rust generation area ratio 5% or more, less than 10%
○-: White rust generation area ratio of 10% or more and less than 25%
Δ: White rust generation area ratio 25% or more, less than 50%
X: White rust generation area ratio 50% or more
[0162]
(4) Paint adhesion
For each sample, a melamine-based baking paint (film thickness 30 μm) was applied, then immersed in boiling water for 2 hours, immediately cut into grids (10 × 10 grids at 1 mm intervals), and with adhesive tape Adhesion / peeling was performed, and the peeled area ratio of the coating film was evaluated. The evaluation criteria are as follows.
A: No peeling
○: Peel area ratio less than 5%
Δ: peeling area ratio 5% or more, less than 20%
X: Peel area ratio 20% or more
[0163]
(5) Workability
Deep drawing (oil-free conditions) was performed with a blank diameter of 120 mm and a die diameter of 50 mm, and the molding height until cracking was evaluated. The evaluation criteria are as follows.
◎: Aperture
○: Molding height 30 mm or more
Δ: Molding height 20 mm or more and less than 30 mm
×: Molding height less than 20 mm
[0164]
[Table 1]

[0165]
[Table 2]

[0166]
[Table 3]

[0167]
[Table 4]

[0168]
[Table 5]

[0169]
[Table 6]

[0170]
In Table 7 to Table 39 below, * 1 to * 7 described in the table indicate the following contents.
* 1: Plated steel plate No. in Table 1
* 2: Composition No. 1 for the first layer film described in Table 2 and Table 3.
* 3: Component (β) is P₂O₅Deposit in terms of conversion, component (γ) is the amount of deposit in terms of Mg, Mn, Al metal amount
* 4: Resin composition for second layer coating described in Table 4
* 5: Rust prevention additive component No. described in Table 5
* 6: Solid lubricant Nos. Listed in Table 6
* 7: Compounding amount (parts by weight) with respect to 100 parts by weight of the solid content of the resin composition
[0171]
[Table 7]

[0172]
[Table 8]

[0173]
[Table 9]

[0174]
[Table 10]

[0175]
[Table 11]

[0176]
[Table 12]

[0177]
[Table 13]

[0178]
[Table 14]

[0179]
[Table 15]

[0180]
[Table 16]

[0181]
[Table 17]

[0182]
[Table 18]

[0183]
[Table 19]

[0184]
[Table 20]

[0185]
[Table 21]

[0186]
[Table 22]

[0187]
[Table 23]

[0188]
[Table 24]

[0189]
[Table 25]

[0190]
[Table 26]

[0191]
[Table 27]

[0192]
[Table 28]

[0193]
[Table 29]

[0194]
[Table 30]

[0195]
[Table 31]

[0196]
[Table 32]

[0197]
[Table 33]

[0198]
[Table 34]

[0199]
[Table 35]

[0200]
[Table 36]

[0201]
[Table 37]

[0202]
[Table 38]

[0203]
[Table 39]

[0204]
[Example 2]
In order to obtain organic coated steel sheets for home appliances, building materials, and automobile parts, Table 1 shows various zinc-based plating or aluminum-based plating applied to cold-rolled steel sheets having a thickness of 0.8 mm and a surface roughness Ra of 1.0 μm. After using the plated steel plate as the treated original plate, the surface of the plated steel plate was subjected to alkaline degreasing treatment, water-washing and drying, and then the treatment liquids (film compositions) shown in Tables 2 and 3 were applied with a roll coater and dried by heating. A layer film was formed. The adhesion amount of the first layer film was adjusted by the solid content of the treatment liquid (heating residue) or coating conditions (rolling force of the roll, rotation speed, etc.). Subsequently, the coating composition shown in Table 4 was applied by a roll coater and heated and dried to form a second layer film, thereby producing organic coated steel sheets of Examples of the present invention and Comparative examples. The adhesion amount of the second layer film was adjusted by the solid content (heating residue) of the coating composition or the coating conditions (roll rolling force, rotational speed, etc.).
[0205]
The obtained organic coated steel sheet was evaluated for quality performance (film appearance, white rust resistance, white rust resistance after alkali degreasing, paint adhesion, workability, spot weldability, conductivity). The results are shown in Tables 40 to 57 together with the film configurations of the first layer film and the second layer film.
The spot weldability and conductivity of the organic coated steel sheet were evaluated as follows, and the other performances were evaluated in the same manner as in [Example 1].
[0206]
(6) Spot weldability
Using a test piece with a plate thickness of 1.2 mm, an upper electrode CR type (original diameter 16 mm, tip diameter 5.4 mm), lower electrode F type (tip diameter 16 mm), pressurization pressure 300 kg, energization time 13 cycles (60 Hz) Under the conditions, a spot spot weldability continuous spot test was performed, and the case where the nugget diameter was smaller than 4.4 mm was regarded as the limit of the weld spot, and was evaluated as follows.
◎: More than 3000 consecutive hit points
○: Continuous hitting point 1000 points or more and less than 3000 points
Δ: Continuous hitting point of 500 points or more and less than 1000 points
×: Less than 500 consecutive hit points
[0207]
(7) Conductivity (surface resistance value)
Using a four-probe resistivity meter (“Loresta AP” manufactured by Mitsubishi Chemical Corporation), the surface resistance of the test piece was measured and evaluated as follows.
A: Surface resistance value 10^-4Ω or less
○: Surface resistance value 10^-4Over Ω, 10^-3Ω or less
Δ: Surface resistance value 10^-3Over Ω, 10²Ω or less
X: Surface resistance value 10²Over Ω
[0208]
In Table 40 to Table 57 below, * 1 to * 7 described in the table indicate the following contents.
* 1: Plated steel plate No. in Table 1
* 2: Composition No. 1 for the first layer film described in Table 2 and Table 3.
* 3: Component (β) is P₂O₅Deposit in terms of conversion, component (γ) is the amount of deposit in terms of Mg, Mn, Al metal amount
* 4: Resin composition for second layer coating described in Table 4
* 5: Rust prevention additive component No. described in Table 5
* 6: Solid lubricant Nos. Listed in Table 6
* 7: Compounding amount (parts by weight) with respect to 100 parts by weight of the solid content of the resin composition
[0209]
[Table 40]

[0210]
[Table 41]

[0211]
[Table 42]

[0212]
[Table 43]

[0213]
[Table 44]

[0214]
[Table 45]

[0215]
[Table 46]

[0216]
[Table 47]

[0217]
[Table 48]

[0218]
[Table 49]

[0219]
[Table 50]

[0220]
[Table 51]

[0221]
[Table 52]

[0222]
[Table 53]

[0223]
[Table 54]

[0224]
[Table 55]

[0225]
[Table 56]

[0226]
[Table 57]

[0227]
【The invention's effect】
As described above, the organic coated steel sheet of the present invention does not contain any hexavalent chromium in the processing solution at the time of production or the coating film component of the product, and has high corrosion resistance as an organic coated steel sheet for use in building materials, home appliances, automobiles, etc. It also has excellent film appearance and paint adhesion.
In addition, by restricting the amount of adhesion between the first layer coating and the second layer coating to a specific range, strict electrical conductivity is required for noise suppression of the product, and high productivity is required in the assembly process of the chassis and the like. It is possible to obtain an organic coated steel sheet having excellent corrosion resistance, high conductivity, and spot weldability, which is suitable as a material for OA equipment, AV equipment and the like that require high spot weldability.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows an organic coating on an organic coated steel sheet in which a composite oxide film satisfying the conditions of the present invention is formed on a galvanized steel sheet and an organic film whose constituent components satisfy the conditions of the present invention is formed thereon. Graph showing the relationship between quantity and corrosion resistance
[Fig. 2] Adhesion of organic film on an organic coated steel sheet in which a composite oxide film satisfying the conditions of the present invention is formed on the surface of a galvanized steel sheet and an organic film whose constituent components satisfy the conditions of the present invention is formed thereon. Graph showing the relationship between quantity and spot weldability
[Fig. 3] Adhesion of organic film on an organic coated steel sheet in which a composite oxide film satisfying the conditions of the present invention is formed on the surface of a galvanized steel sheet and an organic film whose constituent components satisfy the conditions of the present invention is formed thereon. Graph showing the relationship between quantity and conductivity

Claims (14)

On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
(Α) oxide fine particles,
(Β) phosphoric acid and / or a phosphoric acid compound;
(Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (e), (g) and (h) rust preventive additive component (Y), and the blending ratio of the following (e), (g) and (h) is a solid weight ratio ( e) / (g) + (h) = 20 / 80-80 / 20, (g) / (h) = 20 / 80-80 / 20,
(E) Molybdate (g) Calcium compound (h) Phosphate and / or silicon oxide The total content of the antirust additive component (Y) is 100 parts by weight (solid content) of the reaction product (X). 1 to 100 parts by weight (solid content), an organic coated steel sheet having excellent corrosion resistance, having an organic film with a film thickness of 0.1 to 5 μm. On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
(Α) oxide fine particles,
(Β) phosphoric acid and / or a phosphoric acid compound;
(Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (f), (g) and (h) rust preventive additive component (Y), and the blending ratio of the following (f), (g) and (h) is a solid weight ratio ( f) / (g) + (h) = 20 / 80-80 / 20, (g) / (h) = 20 / 80-80 / 20,
(F) one or more organic compounds selected from triazoles, thiadiazoles, thiazoles, thiurams (g) calcium compounds (h) phosphates and / or silicon oxides of the antirust additive component (Y) The total content is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X), and the organic film having a film thickness of 0.1 to 5 μm is provided. Organic coated steel sheet with excellent corrosion resistance. On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
(Α) oxide fine particles,
(Β) phosphoric acid and / or a phosphoric acid compound;
(Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (f) and (i) rust preventive additive component (Y), and the blending ratio of (f) and (i) below is (f) / (i) = 20 in terms of the weight ratio of the solid content. / 80-80 / 20,
(F) One or more organic compounds selected from triazoles, thiadiazoles, thiazoles, and thiurams (i) Ca ion-exchanged silica The total content of the antirust additive (Y) is the reaction product. (X) An organic coated steel sheet having excellent corrosion resistance, having an organic film with a film thickness of 0.1 to 5 μm, which is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) . On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
(Α) oxide fine particles,
(Β) phosphoric acid and / or a phosphoric acid compound;
(Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (e) and (f) anti-rust additive component (Y), and the blending ratio of (e) and (f) below is the weight ratio of solids (e) / (f) = 20 / 80-80 / 20,
(E) Molybdate (f) One or more organic compounds selected from triazoles, thiadiazoles, thiazoles, and thiurams The total content of the rust preventive additive component (Y) is the reaction product ( X) An organic coated steel sheet excellent in corrosion resistance, characterized by having an organic film having a thickness of 0.1 to 5 μm, which is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content). On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
(Α) oxide fine particles,
(Β) phosphoric acid and / or a phosphoric acid compound;
(Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (e), (f), (g) and (h) antirust additive component (Y), and the following (e), (f), (g) and (h) (E) / (f) = 20 / 80-80 / 20, (e) / (g) + (h) = 20 / 80-80 / 20, (f) / (g) + (H) = 20 / 80-80 / 20, (g) / (h) = 20 / 80-80 / 20,
(E) molybdate (f) one or more organic compounds selected from triazoles, thiadiazoles, thiazoles, thiurams (g) calcium compound (h) phosphate and / or silicon oxide Organic with a film thickness of 0.1 to 5 μm, wherein the total content of additive component (Y) is 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X) An organic coated steel sheet excellent in corrosion resistance, characterized by having a film. On the surface of the zinc-based plated steel sheet or aluminum-based plated steel sheet,
(Α) oxide fine particles,
(Β) phosphoric acid and / or a phosphoric acid compound;
(Γ) one or more metals selected from Mg, Mn, and Al (including the case where they are included as a compound and / or a composite compound);
Having a composite oxide film having a film thickness of 0.005 to 3 μm,
A reaction product (X) of a film-forming organic resin (A) and an active hydrogen-containing compound (B) comprising a hydrazine derivative (C) in which a part or all of the compounds have active hydrogen as a second layer film on the upper part. And the following (e), (f) and (i) anti-rust additive component (Y), and the blending ratio of the following (e), (f) and (i) is a weight ratio of solids ( e) / (f) = 20 / 80-80 / 20, (e) / (i) = 20 / 80-80 / 20, (f) / (i) = 20 / 80-80 / 20,
(E) Molybdate (f) One or more organic compounds selected from triazoles, thiadiazoles, thiazoles, thiurams (i) Ca ion-exchanged silica Total content of the antirust additive (Y) Corrosion resistance characterized by having an organic film having a film thickness of 0.1 to 5 μm in an amount of 1 to 100 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X). Excellent organic coated steel sheet.   The organic film further contains a solid lubricant (Z), and the content of the solid lubricant (Z) is 1 to 80 parts by weight (solid content) with respect to 100 parts by weight (solid content) of the reaction product (X). The organic-coated steel sheet having excellent corrosion resistance according to claim 1, 2, 3, 4, 5 or 6.   The organic coated steel sheet excellent in corrosion resistance according to claim 1, 2, 3, 4, 5, 6 or 7, wherein the film-forming organic resin (A) is an epoxy group-containing resin (D).   The hydrazine derivative (C) having an active hydrogen is a pyrazole compound having an active hydrogen and / or a triazole compound having an active hydrogen, characterized in that: Organic coated steel sheet with excellent corrosion resistance as described in 1.   The hydrazine derivative (C) having active hydrogen is contained in the active hydrogen compound (B) in an amount of 10 to 100 mol%, according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9. Organic coated steel sheet with excellent corrosion resistance as described. The organic coated steel sheet excellent in corrosion resistance according to claim 8, 9 or 10, wherein the epoxy group-containing resin (D) is an epoxy resin represented by the following formula (1).

  The component (α) contained in the composite oxide film is silicon oxide, and the corrosion resistance according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11 is characterized. Excellent organic coated steel sheet.   The organic coating excellent in corrosion resistance according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12, wherein the composite oxide film further contains an organic resin. steel sheet. In the composite oxide film, the total adhesion amount of the component (α), the component (β) in terms of P ₂ O ₅ , and the component (γ) in terms of metals of Mg, Mn, and Al is 6 to 1000 mg / m ² . And the organic film has an adhesion amount of 0.1 g / m ² or more and less than 0.5 g / m ² . An organic coated steel sheet having excellent corrosion resistance according to 10, 11, 12 or 13.

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