JP4757367B2 - Rust prevention treatment method and rust prevention treatment metal material - Google Patents

Description

【００１９】
を有する化合物は、式（２）
【００２０】
【化２】

【００２１】
のように窒素原子や酸素原子を同時に有するものの方が好ましい。これらの化合物では窒素原子や酸素原子も亜鉛と配位結合を形成することができるため、特にこれらの原子を同時に有するチオカルボニル基含有化合物では亜鉛表面にキレート結合を形成しやすくなり、チオカルボニル基含有化合物が亜鉛表面に強固に吸着することが可能である。不活性な亜鉛表面のサイト（例えば酸化物の表面）にはチオカルボニル基含有化合物は吸着されないが、このような不活性な面に対しては、リン酸イオンが作用して、リン酸亜鉛を形成し、活性な面を形成する。このように活性化された面にチオカルボニル基含有化合物が吸着するので、亜鉛表面全体に防錆効果を発揮するものと推定される。また、（２）チオカルボニル基含有化合物も、リン酸イオンも、樹脂皮膜の架橋促進剤として作用する。両者の相乗作用により、樹脂皮膜のミクロポアを少なくして水や塩素イオン等の有害イオンを効率よく遮断することができると推定される。
【００２２】
注目すべきことに、上記のチオカルボニル基含有化合物とリン酸イオン、バナジウム酸イオンによる優れた防錆作用に加えて、これに水分散性シリカを添加すると更に防錆作用が促進することが発見された。
【００２３】
水分散性シリカは、リン酸イオンやチオカルボニル基含有化合物、バナジウム酸イオン等の防錆イオンや分子をシリカ表面に吸着させ、腐食反応が生じている亜鉛めっき表面の部位に適宜防錆イオンや分子を放出させることで防錆作用を高めていると考えられる。
【００２４】
以上述べてきたように、本発明で用いる防錆剤は防錆イオン等による金属表面の不動態化を図る上できわめて有効であり、通常は、防錆皮膜として有効な皮膜とするために造膜成分である有機樹脂（本発明の場合、この有機樹脂は、一般に水溶性である本発明の防錆剤の特性から水性樹脂に由来するものとなる）との混合物として用いられる。しかしながら、防錆処理皮膜として十分な性能を得るためには防錆皮膜の金属素地への密着性を有することと、防錆皮膜に傷等の皮膜欠陥が生じた際に、傷部の金属素地へ不動態化イオンが有効に供給されることが重要である。ところが、本発明における防錆剤であるチオカルボニル基含有化合物、バナジウム酸化合物又はリン酸イオンを水性樹脂に含有させ、金属素地に塗布・乾燥させた場合には、素地表面の防錆剤濃度を意識的に高めることができないために、場合によっては防錆剤の作用を高めるのに限界があることがある。そこで、樹脂を含むコーティング剤の塗布に先立って、防錆剤のみからなる水溶液を塗布することで、防錆剤が素地表面と十分に反応して不動態層が形成され、更に乾燥・焼き付けることにより防錆剤が素地表面に十分な量で固着し、引き続いて塗布する水性樹脂層と素地金属との密着性を飛躍的に高めることが可能となる。こうすることで、防錆膜に傷等の皮膜欠陥が導入された場合にも、素地表面には防錆剤が固着していることから、水の浸透等によりイオン化し素地表面の傷を速やかに不動態化することが可能となり耐食性が著しく向上する。この作用は、防錆剤含有樹脂を一段で塗布した処理層ではとうてい得られないものである。
【００２５】
このように、本発明では、防錆剤としてリン酸イオン、チオカルボニル基含有化合物及びバナジウム酸化合物のうちの少なくとも１種を含む水溶液の防錆コーティング剤Ａを、被処理金属材の亜鉛系金属被覆鋼又は無被覆鋼に最初に塗布し、そして次に、水性樹脂及び水からなる防錆コーティング剤Ｂを塗布する。コーティング剤Ａは、水分散性シリカを任意に含むことができ、またコーティング剤Ｂは、リン酸イオンと水分散性シリカの少なくとも一方を更に含むことができる。
【００２６】
【発明の実施の形態】
以下、本発明を詳細に説明する。
本発明においてチオカルボニル基含有化合物とは、下式で表されるチオカルボニル基（１）
【００２７】
【化３】

【００２８】
を有する化合物をいうが、更に、水溶液中や酸またはアルカリの存在下においてチオカルボニル基含有化合物を放出することのできる化合物をも含むことができる。チオカルボニル基含有化合物の代表例としては、式（３）
【００２９】
【化４】

【００３０】
で表されるチオ尿素およびその誘導体等、例えばメチルチオ尿素、ジメチルチオ尿素、エチルチオ尿素、ジエチルチオ尿素、ジフェニルチオ尿素、チオペンタール、チオカルバジド、チオカルバゾン類、チオシアヌル酸類、チオヒダントイン、２−チオウラミル、３−チオウラゾール等；式（４）
【００３１】
【化５】

【００３２】
で表されるチオアミド化合物（式中のＲは、例えば−Ｈ，−ＣＨ₃ ，−ＣＨ₂ ＣＨ₃ ，−Ｃ₆ Ｈ₅ ，−Ｃ₈ Ｈ₅ ，Ｃ₅ Ｈ₃ ＳＯ等を表す）、例えばチオホルムアルデヒド、チオカルボスチリル、チオサッカリン等；式（５）
【００３３】
【化６】

【００３４】
で表されるチオアルデヒド化合物（式中のＲは、例えば−Ｈ，−ＣＨ₃ 等を表す）、例えばチオホルムアルデヒド、チオアセトアルデヒド等；式（６）
【００３５】
【化７】

【００３６】
で表されるカルボチオ類（式中のＲは、例えば−ＣＨ₃ ，−Ｃ₆ Ｈ₅ 等を表す）、例えばチオ酢酸、チオ安息香酸、ジチオ酢酸等；式（７）
【００３７】
【化８】

【００３８】
で表されるチオ炭酸類や、その他式（１）構造を有する化合物、例えばチオクマゾン、チオクモチアゾン、チオニンブルーＪ、チオピロン、チオピリン、チオベンゾフェノン等が例示できる。これらの化合物の中で直接水に溶解しないものは、アルカリ溶液中で一旦溶解させた後防錆コーティング剤中に配合する。
【００３９】
ここで、防錆コーティング剤中のチオカルボニル基含有化合物が０．２ｇ／ｌ未満の場合には、耐食性は不十分となり、一方、２００ｇ／ｌを超えると耐食性が飽和して不経済となる。
【００４０】
バナジウム酸化合物は０．１ｇ／ｌ未満の場合には、耐食性が不十分となり、一方、１００ｇ／ｌを超えると耐食性が飽和して不経済となる。
【００４１】
バナジウム酸化合物はバナジウム酸、バナジウム酸アンモニウム、バナジウム酸ナトリウム、バナジウム酸カリウム、バナジウム酸ストロンチウム、バナジウム酸水素ナトリウム等のバナジウム酸塩、またリンバナジウム酸、リンバナジウム酸アンモニウム等のリンバナジウム酸塩等の形で供給することができる。
【００４２】
また、リン酸イオンは、金属素地にリン酸塩層を形成させ、不動態化させるとともに樹脂層と素地との密着性を著しく向上させ、更に水性樹脂由来の樹脂皮膜の架橋反応を促進させ、緻密な防錆膜を形成することにより、防錆性を更に向上させる。リン酸イオンの含有量が０．１ｇ／ｌ未満の場合には、防錆効果が十分に発揮されず、一方、１００ｇ／ｌを超えると耐食性が飽和して不経済となるだけではなく、樹脂含有水溶液（コーティング剤Ｂ）に添加する場合には、５ｇ／ｌを超えると使用する水性樹脂によっては樹脂がゲル化し塗布不能となる。従って、リン酸イオン含有量は、コーティング剤Ａでは０．１〜１００ｇ／ｌ、コーティング剤Ｂでは０．１〜５ｇ／ｌとする。
【００４３】
リン酸イオンを供給するリン酸イオン源としては、オルトリン酸、縮合リン、種々の金属のオルトリン酸塩または縮合リン酸塩、五酸化リン、リン酸塩鉱物、市販の複合リン酸塩顔料、またはこれらの混合物が挙げられる。ここで言うオルトリン酸塩の中には、その一水素塩（ＨＰＯ₄ ^2- の塩）、二水素塩（Ｈ₂ ＰＯ₄ ^- の塩）も含むものとする。また縮合リン酸塩の中にも水素塩を含むこととする。また縮合リン酸塩にはメタリン酸塩も含み、通常のポリリン酸塩、ポリメタリン酸塩も含むものとする。これらのリン化合物の具体例としてはリン酸塩鉱物、例えばモネタイト、トルフィル石、ウィトロック石、ゼノタイム、スターコライト、ストルーブ石、ラン鉄鉱等や、市販の複合リン酸塩顔料、例えばポリリン酸シリカ等や、複合リン酸、例えばピロリン酸、メタリン酸や、複合リン酸塩、例えばメタリン酸塩、テトラメタリン酸塩、ヘキサメタリン酸塩、ピロリン酸塩、酸性ピロリン酸塩、トリポリリン酸塩や、あるいはこれらの混合物が挙げられる。リン酸塩を形成する金属種は特に限定的でなく、アルカリ金属、アルカリ土類金属、その他の典型元素の金属種および遷移金属が挙げられる。好ましい金属種の例としては、マグネシウム、カルシウム、ストロンチウム、バリウム、チタン、ジルコニウム、マンガン、鉄、コバルト、ニッケル、亜鉛、アルミニウム、鉛、スズ等が挙げられる。この他にバナジル、チタニル、ジルコニル等、オキソカチオンも含まれる。特に好ましいのはカルシウム、マグネシウムである。
【００４４】
本発明に係わる防錆コーティング剤に更に、水分散性シリカを添加することにより耐食性が一層向上する。しかも耐食性に加えて乾燥性、耐擦傷性、塗膜密着性をも改良することができる。
【００４５】
本発明において水分散性シリカとは、微細な粒径を有するため水中に分散させた場合に安定な状態を保持でき半永久的に沈降が認められないような特性を有するシリカを総称していうものである。上記水分散性シリカとしては、ナトリウム等の不純物が少なく弱アルカリ系のものであれば特に限定されない。例えば、「スノーテックスＮ」（日産化学工業製）、「アデライトＡＴ−２０Ｎ」（旭電化工業社製）等の市販シリカゲル、または市販のアエロジル粉末シリカ粒子等を用いることができる。
【００４６】
水分散性シリカの含有量は、防錆コーティング剤１リットル中に、樹脂を含まないコーティング剤Ａでは１０〜３００ｇ／ｌ、樹脂を含むコーティング剤Ｂでは５０〜５００ｇ／ｌであることが好ましく、含有量がこれらの下限未満の場合には耐食性の向上効果が不十分であり、一方これらの上限を超えると耐食性が飽和して不経済となる。
【００４７】
また、水性樹脂とシリカ粒子、顔料（任意成分として配合されることがある）との親和性を向上させ、更に水性樹脂と亜鉛または鉄のリン酸化物層との密着性等を向上させるためにシランカップリング剤もしくはその加水分解縮合物又はそれらの両方を配合してもよい。ここでの「シランカップリング剤の加水分解縮合物」とは、シランカップリング剤を原料とし、加水分解重合させたシランカップリング剤のオリゴマーのことをいう。
【００４８】
本発明で使用できる上記のシランカップリング剤としては特に制限はないが、好ましいものとしては、例えば以下のものを挙げることができる：ビニルメトキシシラン、ビニルトリメトキシシラン、ビニルエトキシシラン、ビニルトリエトキシシラン、３−アミノプロピルトリエトキシシラン、３−グリシドキシプロピルトリメトキシシラン、３−メタクリロキシプロピルトリメトキシシラン、３−メルカプトプロピルトリメトキシシラン、Ｎ−（１，３−ジメチルブチリデン）−３−（トリエトキシシリル）−１−プロパンアミン、Ｎ，Ｎ′−ビス〔３−（トリメトキシシリル）プロピル〕エチレンジアミン、Ｎ−（β−アミノエチル）−γ−アミノプロピルメチルジメトキシシラン、Ｎ−（β−アミノエチル）−γ−アミノプロピルトリメトキシシラン、γ−アミノプロピルトリメトキシシラン、γ−アミノプロピルトリエトキシシラン、γ−グリシドキシプロピルトリメトキシシラン、γ−グリシドキシプロピルトリエトキシシラン、γ−グリシドキシプロピルメチルジメトキシシラン、２−（３，４−エポキシシクロヘキシル）エチルトリメトキシシラン、γ−メタクリロキシプロピルトリメトキシシラン、γ−メタクリロキシプロピルトリエトキシシラン、γ−メルカプトプロピルトリメトキシシラン、γ−メルカプトプロピルトリエトキシシラン、Ｎ−〔２−（ビニルベンジルアミノ）エチル〕−３−アミノプロピルトリメトキシシラン。
【００４９】
特に好ましいシランカップリング剤は、ビニルトリメトキシシラン、ビニルエトキシシラン、３−アミノプロピルトリエトキシシラン、３−グリシドキシプロピルトリメトキシシラン、３−メタクリロキシプロピルトリメトキシシラン、３−メルカプトプロピルトリメトキシシラン、Ｎ−（１，３−ジメチルブチリデン）−３−（トリエトキシシリル）−１−プロパンアミン、Ｎ，Ｎ′−ビス〔３−（トリメトキシシリル）プロピル〕エチレンジアミンである。これらシランカップリング剤は１種類を単独で使用してもよいし、または２種類以上を併用してもよい。
【００５０】
本発明で、上記シラン化合物は、水溶液１リットル中に０．０２〜１００ｇの濃度で使用する。シラン化合物の添加量が０．０２ｇ未満になると添加効果の低下が認められ、１００ｇを越えると貯蔵安定性が低下し、好ましくない。
【００５１】
本発明の防錆コーティング剤Ｂは水性樹脂を含む。本発明において水性樹脂とは、水溶性樹脂のほか、本来水不溶性でありながらエマルジョンやサスペンジョンのように不溶性樹脂が水中に微分散された状態のものを含めていう。このような水性樹脂として使用できる樹脂としては、例えばポリオレフィン系樹脂、ポリウレタン系樹脂、アクリル系樹脂、ポリカーボネート系樹脂、エポキシ系樹脂、ポリエステル系樹脂、アルキド系樹脂、フェノール系樹脂、その他の加熱硬化型の樹脂等を例示でき、架橋可能な樹脂であることがより好ましい。特に好ましい樹脂は、ポリオレフィン系樹脂、ポリウレタン系樹脂、および両者の混合樹脂系である。水性樹脂は２種以上を混合して使用してもよい。
【００５２】
本発明の樹脂を含有する防錆コーティング剤Ｂは、水性樹脂（水溶性樹脂、水分散性樹脂を含む）を固形分で１〜８０重量部および水９９〜２０部を主成分とする組成物であり、この組成物１リットル中に０．１〜５ｇ、好ましくは０．１〜３ｇのリン酸イオン、そして５０〜５００ｇ、好ましくは１００〜４００ｇの水分散性シリカを任意に含有する。
【００５３】
また、本発明のコーティング剤Ｂは、更に他の成分が配合されていてもよい。例えば、顔料、界面活性剤等を挙げることができる。
【００５４】
顔料としては、例えば酸化チタン（ＴｉＯ₂ ）、酸化亜鉛（ＺｎＯ）、酸化ジルコニウム（ＺｒＯ）、炭酸カルシウム（ＣａＣＯ₃ ）、硫酸バリウム（ＢａＳＯ₄ ）、アルミナ（Ａｌ₂ Ｏ₃ ）、カオリンクレー、カーボンブラック、酸化鉄（Ｆｅ₂ Ｏ₃ ，Ｆｅ₃ Ｏ₄ ）等の無機顔料や、有機顔料等を用いることができる。
【００５５】
本発明の樹脂を含有する防錆コーティング剤Ｂには水性樹脂の造膜性を向上させ、より均一で平滑な塗膜を形成するために、溶剤を用いてもよい。溶剤としては、塗料に一般的に用いられているものであれば特に限定されず、例えば、アルコール系、ケトン系、エステル系、エーテル系のもの等を挙げることができる。
【００５６】
本発明では、上述の防錆コーティング剤Ａ及びＢを亜鉛被覆鋼または無被覆鋼等の金属材用防錆コーティング剤として使用して、そのような金属材の防錆処理を行う。この防錆処理は、まず、樹脂を含有しない防錆コーティング剤Ａを被塗物に塗布後に被塗物を熱風で加熱し乾燥させ、次に樹脂を含有する防錆コーティング剤Ｂを塗布し、加熱し乾燥させる方法で実施することができる。
【００５７】
上記加熱の温度は、樹脂を含まない層（第１層）、樹脂を含む層（第２層）のいずれにおいても５０〜２５０℃が適当である。５０℃未満であると水分の蒸発速度が遅く十分な成膜性が得られないので防錆力が不足する。一方、２５０℃を超えると、特に樹脂を含む系の場合、水性樹脂の熱分解が生じるので、耐塩水噴霧試験性、耐水性が低下し、また外観も黄変することから、上記範囲に限定される。塗布後に被塗物を熱風で加熱し、乾燥させる場合の乾燥時間は、１秒〜５分が好ましい。
【００５８】
上記防錆処理において、本発明の防錆コーティング剤の付着量は、第１層（コーティング剤Ａによる層）は５mg／ｍ² 以上が望ましい。５mg／ｍ² 未満であると、第２層（コーティング剤Ｂによる層）の密着力や耐食性が不足する。一方、上限は望ましくは１００mg／ｍ² がよい。付着量が多すぎると塗装下地処理としての効果が飽和する上に不経済であり、より好ましくは、５mg／ｍ² 〜５０mg／ｍ² である。塗布方法は、特に限定されず、浸せき法やコーター塗布法、スプレー塗布法等で塗布される。塗布後に被塗物を熱風炉や直火炉、ＩＨ炉等で加熱し、乾燥させる。
【００５９】
第２層の防錆コーティング剤Ｂの塗装膜厚は、乾燥膜厚が０．１μｍ以上であることが望ましい。０．１μｍ未満であると、防錆力が不足する。一方、乾燥膜厚が厚すぎると、加工時の割れ等の不具合が発生し、不経済であるので２０μｍ以下がよく、より好ましくは０．１〜１０μｍである。塗布方法は、特に限定されず、一般に使用されるロールコート、エアースプレー、エアーレススプレー、浸せき等によって塗布することができる。塗布後に被塗物を熱風炉や直火炉、ＩＨ炉等で加熱し、乾燥させる。
【００６０】
本発明の防錆コーティング剤によってコーティングされる材としては、上述したように亜鉛系金属被覆鋼および無被覆鋼である。亜鉛系金属被覆鋼は具体的には、亜鉛めっき、亜鉛とＦｅ，Ｎｉ，Ｃｏ，Ｃｒ，Ｍｇ，Ａｌ，Ｓｉ，Ｍｎ等の１種または２種以上からなる合金めっきを施した鋼材をさす。さらにＡｌ被覆鋼においても同様の効果が得られる。Ａｌ被覆鋼は具体的にはＡｌめっき、あるいはＡｌとＳｉ，Ｍｇ，Ｍｎ，Ｆｅ，Ｎｉ，Ｃｏ，Ｃｒ等の１種又は２種以上とからなる合金めっきを施した鋼材をさす。めっき方法は、特に限定されるものではなく、電気めっき法、溶融めっき法、真空めっき法等いずれでもよい。鋼材としては、特に限定されないが冷延鋼板、熱延鋼板、厚板、棒鋼、鋼管等の鋼材でよい。
【００６１】
また、本発明の防錆コーティング剤は、上記のように塗装下地処理剤および水性防錆塗料として使用できると共に、いわゆる一次防錆剤としても適用し得る。
更に、コイルコーティングの分野での亜鉛系めっき鋼板の潤滑膜の下地処理や塗装下地処理に利用できるだけでなく、本発明の樹脂を含有する防錆コーティング剤中にワックスを添加することにより潤滑鋼板用の潤滑防錆剤としても利用できる。
【００６２】
次に、実施例により本発明を更に説明する。なお、以下の各例において、ｇ／ｌで表した濃度は防錆コーティング剤の１リットル中に含有される各成分の含有量（ｇ）を意味する。
また、以下の各例において耐食性の評価は次の方法により行った。
【００６３】
〔評価方法〕
（Ａ）防錆性
ａ）供試体の作製
本発明の樹脂を含有しない防錆コーティング剤Ａを市販の電気亜鉛めっき鋼板ＥＧ−ＭＯ材にバーコート＃３で付着量３０mg／ｍ² となるように塗布した後、到達板温（ＰＭＴ）７０℃となるように乾燥させ、空冷後本発明の樹脂を含有する防錆コーティング剤Ｂをバーコート＃３で乾燥膜厚が１μｍとなるように塗布した後、ＰＭＴ１５０℃となるように乾燥させた。
【００６４】
ｂ）塩水噴霧試験
ＪＩＳ Ｚ２３７１に準拠した試験法により５％の食塩水を３５℃で被塗物面に噴霧し、２４０時間後の白錆の程度を１０点満点で評価した。評価は平面部とエリクセン７mm押し出し加工部の両方について行った。また、評価基準は下記のものとした。

【００６５】
（Ｂ）上塗密着性
ａ）供試体の作製
本発明の樹脂を含有しない防錆コーティング剤Ａを市販の電気亜鉛めっき鋼板ＥＧ−ＭＯ材にバーコート＃３で付着量３０mg／ｍ² となるように塗布した後、ＰＭＴ７０℃となるように乾燥させ、空冷後本発明の樹脂を含有する防錆コーティング剤Ｂをバーコート＃３で乾燥膜厚が１μｍとなるように塗布した後、ＰＭＴ１５０℃となるように乾燥させた。乾燥後、スーパーラック１００（日本ペイント社製；アクリルメラミン塗料）を乾燥膜厚２０μｍとなるようにバーコートで塗布した後にＰＭＴ１５０℃で２０分間乾燥させて上塗密着試験板を作製した。
【００６６】
ｂ）１次密着試験
碁盤目：碁盤目１mmのカットを入れた部分のテープ剥離性を評価し、それを下記の基準で１０点満点で評価した。
エリクセン７mm：エリクセンで７mmまで押し出し加工した部分にテープを貼り、テープ剥離性を同様に評価した。
碁盤目＋エリクセン７mm：碁盤目１mmのカットを入れた部分をエリクセンで７mmまで押し出し加工した部分にテープを貼り、テープ剥離性を同様に評価した。
評価基準は下記のものとした。

【００６７】
ｃ）２次密着試験
試験板を沸水中に３０分浸漬後、１次試験と同様の試験及び評価を実施した。
【００６８】
（実施例１）
純水にリン酸アンモニウムをリン酸イオンが０．１ｇ／ｌとなるように溶かし、ディスパーで３０分間撹拌分散させ、ｐＨ８．０となるように調整して第１層の防錆コーティング剤Ａを得た。一方、純水にポリオレフィン系樹脂「ハイテックＳ−７０２４」（商品名；東邦化学（株）製）を樹脂固形分の濃度が２０重量％となるように添加し、ディスパーで３０分間撹拌分散させ、ｐＨ８．０となるように調整して第２層の防錆コーティング剤Ｂを得た。得られた防錆コーティング剤を、１次防錆性および上塗密着性について評価するため、上記評価方法のところで記載したようにして、市販の電気亜鉛めっき鋼板「ＥＰ−ＭＯ」（日本テキストパネル社製、７０×１５０×０．８mm）に塗布し乾燥させた。電気亜鉛めっき鋼板は、アルカリ脱脂剤（「サーフクリーナー５３」、日本ペイント社製）で脱脂、水洗、乾燥後に上記評価を行った。用いた防錆コーティング剤Ａ及びＢの組成とそれらの付着量、膜厚を表１に、また評価結果を表３に示した。
（実施例２〜４１）
実施例１において、第１層のリン酸イオンの添加量、チオカルボニル基含有化合物の種類と添加量、スノーテックス−Ｎ（水分散性シリカ）の添加量、バナジウム酸化合物の添加量、更には、第２層の水溶性樹脂の種類、リン酸イオンの添加量、スノーテックス−Ｎの添加量を表１〜３に記載のようにそれぞれ変えて、実施例１と同様の評価を行い、表５〜７に示した結果を得た。なお、実施例３４〜４１では下記のシラン化合物（シランカップリング剤）を使用した。
Ａ：ビニルトリメトキシシラン
Ｂ：ビニルエトキシシラン
Ｃ：３−アミノプロピルトリエトキシシラン
Ｄ：３−グリシドキシプロピルトリメトキシシラン
Ｅ：３−メタクリロキシプロピルトリメトキシシラン
Ｆ：３−メルカプトプロピルトリメトキシシラン
Ｇ：Ｎ−（１，３−ジメチルブチリデン）−３−（トリエトキシシリル）−１−プロパンアミン
Ｈ：Ｎ，Ｎ′−ビス〔３−（トリメトキシシリル）プロピル〕エチレンジアミン
（比較例１〜８）
実施例１においてリン酸イオン濃度、チオ尿素、スノーテックス−Ｎ、バナジウム酸化合物の濃度を表４に記載のようにそれぞれ変えて、実施例１と同様の評価を行い、表８に示した結果を得た。
【００６９】
【表１】

【００７０】
【表２】

【００７１】
【表３】

【００７２】
【表４】

【００７３】
【表５】

【００７４】
【表６】

【００７５】
【表７】

【００７６】
【表８】

【００７７】
【発明の効果】
以上のように、本発明の防錆処理方法によれば、優れた防錆性が得られる。しかも、本発明の防錆コーティング剤中に使用された成分はいずれも毒性が低く、従って本発明によれば、低公害かつ防錆能に優れたノンクロム防錆処理を施すことができる。
また、本発明の防錆処理方法で処理した防錆処理金属材は、皮膜が形成されているので、錆の発生を効果的に抑制することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rust preventive treatment method for metal materials, particularly zinc-based metal-coated steel such as galvanized steel sheet and uncoated steel, and a rust-proof metal material treated by this method. These rust-proof metal materials are widely used in industrial products such as home appliances, computer-related equipment, building materials, and automobiles.
[0002]
[Prior art]
Galvanized steel sheets and galvannealed steel sheets are not only used in salty atmospheres such as seawater, high-temperature and high-humidity environments, but also in normal indoor environments. Rust prevention power is reduced.
[0003]
In order to prevent white rust, chromate-based rust preventives have been widely used. For example, JP-A-3-131370 discloses an olefin-α, β-ethylenically unsaturated carboxylic acid copolymer resin dispersion. A resin-based rust preventive agent containing a water-dispersible chromium compound and water-dispersible silica is disclosed. However, even the chromium-containing resin treatment agent as described above does not necessarily have sufficient corrosion resistance, and the chromate-treated steel sheet generates white rust when exposed to a salt water or high-temperature and high-humidity atmosphere for a long time. In addition, since chromium compounds have a high risk of harmful effects on the human body, in recent years, there has been an increasing demand for non-chromium rust preventives.
[0004]
The present inventors have found that sulfide ions react with zinc to form a stable ZnS film, and sulfides and sulfur have already been used in JP-A-8-239776 and JP-A-8-67834. Non-chromium rust preventive is disclosed. However, some sulfides give off a specific odor, and handling is not always easy.
[0005]
In addition, a rust preventive using a triazine thiol compound containing a sulfur atom and having no odor or toxicity has been proposed. For example, Japanese Patent Application Laid-Open No. 53-31737 discloses a water-based anticorrosive paint to which a diol-S-triazine derivative is added. Japanese Patent Application Laid-Open No. 61-223062 discloses a reactive emulsion of a thiocarbonyl group-containing compound and a metal obtained by mixing a poorly soluble organic compound in water. ing. However, the water-based anticorrosion paint disclosed in Japanese Patent Application Laid-Open No. 53-31737 is adjusted so as to be more intimately contacted with mild steel or brass. Therefore, it was insufficient as a rust preventive for metal surfaces such as zinc. In addition, since the reactive emulsion disclosed in JP-A-61-223062 is also an emulsion that reacts with copper, nickel, tin, cobalt, aluminum and the like and alloys thereof, as a rust preventive for metal surfaces such as zinc It was insufficient.
[0006]
The present inventors have studied a triazine thiol-containing rust-preventing coating agent that is also effective for rust-preventing galvanized steel sheets, and disclosed the triazine thiol-containing rust-preventing coating agent described in Japanese Patent Application No. 9-2557. However, triazine thiol is an expensive compound, and a cheaper rust preventive agent has been desired.
[0007]
Examples of surface treatment methods for zinc or zinc alloys that do not contain chromium and do not use triazine thiol include those described in JP-A-54-71734 and JP-A-3-226484. JP-A-54-71734 discloses 2 to 6 condensed phosphoric acid esters of myo-inositol or salts thereof from 0.5 to 100 g / l, from the group of titanium fluoride and zirconium fluoride. Zinc or a zinc alloy is surface-treated with an aqueous solution containing 0.5 to 30 g / l of one or more selected in terms of metal and 1 to 50 g / l of thiourea or a derivative thereof. This is a surface treatment method of zinc or zinc alloy. This technique requires titanium fluoride or zirconium fluoride to form a passive film as a protective layer on the zinc surface. Moreover, in what was described in Unexamined-Japanese-Patent No. 3-226854, Ni²⁺And Co²⁺A surface treatment agent that is an aqueous solution of pH 5 to 10 containing one or both of 0.02 g / l or more and one or two of ammonia and a compound having a primary amine group is used. In this technology, in order to provide coating adhesion and post-coating corrosion resistance by precipitation of cobalt or nickel, Ni²⁺And Co²⁺Need at least one of These treatment agents containing metal ions have inconveniences such as an increased load during wastewater treatment.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and its purpose is to provide an inexpensive, non-chromium rust-proofing method effective for metal materials including zinc or galvanized steel sheets and having corrosion resistance higher than that of a chromium-containing rust-proofing agent. Another object of the present invention is to provide a rust-proofing metal material excellent in corrosion resistance which is non-chromium rust-proofed.
[0009]
[Means for Solving the Problems]
The antirust treatment method of the present invention comprises zinc-based metal-coated steel or uncoated steel, 0.1 to 100 g of phosphate ions, 0.2 to 200 g of a thiocarbonyl group-containing compound, and 0. After coating 1 to 100 g of a rust-proof coating agent A containing one or more vanadate compounds, the composition is coated with a rust-proof coating agent B of a composition mainly composed of an aqueous resin and water. And
[0010]
The coating agent A may further contain 10 to 300 g / l of water-dispersible silica.
[0011]
The coating agent B may further contain at least one of 0.1 to 5 g of phosphate ions and 50 to 500 g of water-dispersible silica in 1 liter of the composition mainly composed of the aqueous resin and water. .
[0012]
Moreover, the rust-proofing metal material of this invention is processed by the said rust-proofing method, and the adhesion amount of the coating layer by the coating agent A is 5-100 mg / m.²The thickness of the coating layer with the coating agent B is 0.1 to 10 μm.
[0013]
In general, in order to be effective as a rust-proofing coating agent, (1) prevent penetration of a corrosive liquid, (2) have adhesion to a metal substrate of a rust-proof film, and (3) rust-proof ions The metal surface must be passivated by, for example, (4) water resistance, acid resistance, and alkali resistance of the rust preventive film. If any of these is insufficient, the antirust property cannot be exhibited. Conventional rust preventive chromium compounds were mainly excellent in passivation. Here, “passivation” means that a metal or alloy is in an inactive state in spite of being an environment that can be in an active state chemically or electrochemically.
[0014]
Like chromic acid, sulfides are easily adsorbed on the metal surface and are excellent in oxidation ability, so that the metal surface can be passivated. Therefore, a thiocarbonyl group-containing compound that is one of sulfides has a white rust prevention effect of galvanization.
[0015]
When a vanadium compound is added to a rust inhibitor containing such a thiocarbonyl group-containing compound, the following rust preventive action of vanadate ions is added to further promote the rust preventive effect. That is, the vanadate compound is dissolved in the rust inhibitor as an ion, and depending on the compound and the amount added, the dissolved amount as an ion is saturated and dispersed in the rust inhibitor as a solid, thereby preventing rust. Sometimes it is a pigment. In any case, vanadate ions form a passive film on the zinc surface during coating. This is the reason for the development of the antirust effect by the vanadate compound. In addition, when water, which is a corrosive factor, penetrates into the anticorrosive film and a corrosion site is formed on the zinc surface, vanadate ions eluted from the vanadate compound due to vanadate ions present in the film or permeated water. Is considered to act on the corrosion site and suppress the corrosion reaction.
[0016]
When a vanadate ion coexists with a thiocarbonyl group compound or a phosphate ion, a synergistic action with them is expressed. The reason for this synergistic effect is not necessarily clear, but vanadate ions form a passive film at sites where phosphate ions and thiocarbonyl group-containing compounds cannot be adsorbed, or conversely, vanadate ions passivate. It is considered that the synergistic effect of the anticorrosive action is obtained by adsorbing phosphate ions or thiocarbonyl groups to the defective portions of the film to supplement the action of vanadate ions.
[0017]
Furthermore, when a thiocarbonyl group-containing compound is added together with phosphate ions, the rust-preventing effect is remarkably improved, and a rust-proof coating agent superior to conventional chromium-containing resin-based rust preventive agents can be obtained. This is presumed to be because the antirust effect is exhibited by the synergistic action of the thiocarbonyl group-containing compound and phosphate ions. That is, (1) the thiol group ions in the thiocarbonyl group-containing compound are presumed to be adsorbed on the zinc surface site when the anticorrosive coating agent is applied, and exhibit the antirust effect. Sulfur atoms tend to form coordinate bonds with zinc, but thiocarbonyl groups (formula 1)
[0018]
[Chemical 1]

[0019]
The compound having the formula (2)
[0020]
[Chemical 2]

[0021]
Those having a nitrogen atom and an oxygen atom at the same time are preferred. In these compounds, nitrogen atoms and oxygen atoms can also form coordinate bonds with zinc, and in particular, thiocarbonyl group-containing compounds having these atoms simultaneously tend to form chelate bonds on the zinc surface. The contained compound can be strongly adsorbed on the zinc surface. Although the thiocarbonyl group-containing compound is not adsorbed on the site of the inert zinc surface (for example, the surface of the oxide), phosphate ions act on such an inert surface, and zinc phosphate is Forming an active surface. Since the thiocarbonyl group-containing compound is adsorbed on the activated surface in this way, it is presumed that the zinc surface exhibits a rust preventive effect. (2) Both the thiocarbonyl group-containing compound and the phosphate ion act as a crosslinking accelerator for the resin film. It is presumed that the synergistic action of the two can effectively block harmful ions such as water and chlorine ions by reducing the micropores of the resin film.
[0022]
Remarkably, in addition to the excellent rust prevention effect of the above thiocarbonyl group-containing compound, phosphate ion and vanadate ion, it was discovered that addition of water-dispersible silica further promotes the rust prevention action. It was done.
[0023]
Water-dispersible silica adsorbs rust-preventing ions and molecules such as phosphate ions, thiocarbonyl group-containing compounds, and vanadate ions to the silica surface, and appropriately rust-preventing ions and It is thought that the antirust effect is enhanced by releasing molecules.
[0024]
As described above, the rust preventive agent used in the present invention is extremely effective for the passivation of the metal surface by rust preventive ions and the like, and is usually produced to make the film effective as a rust preventive film. It is used as a mixture with an organic resin that is a film component (in the case of the present invention, this organic resin is derived from an aqueous resin due to the characteristics of the rust inhibitor of the present invention that is generally water-soluble). However, in order to obtain sufficient performance as a rust-proof coating, it has adhesion to the metal substrate of the rust-proof coating, and when a coating defect such as a scratch occurs in the rust-proof coating, the metal substrate of the scratched part It is important that the passivating ions are effectively supplied. However, when a thiocarbonyl group-containing compound, vanadate compound or phosphate ion, which is a rust inhibitor in the present invention, is contained in an aqueous resin and applied to a metal substrate and dried, the concentration of the rust inhibitor on the substrate surface is reduced. In some cases, there is a limit to increasing the action of the rust preventive because it cannot be consciously increased. Therefore, by applying an aqueous solution consisting only of a rust inhibitor prior to the application of a coating agent containing resin, the rust inhibitor reacts sufficiently with the substrate surface to form a passive layer, which is further dried and baked. As a result, the rust inhibitor adheres to the substrate surface in a sufficient amount, and the adhesion between the aqueous resin layer to be applied and the substrate metal can be dramatically improved. In this way, even when a film defect such as a scratch is introduced into the rust preventive film, the rust preventive agent is fixed on the substrate surface. It becomes possible to passivate the material and the corrosion resistance is remarkably improved. This effect cannot be obtained with a treatment layer coated with a rust inhibitor-containing resin in a single step.
[0025]
Thus, in the present invention, the anticorrosive coating agent A of an aqueous solution containing at least one of phosphate ions, thiocarbonyl group-containing compounds and vanadate compounds as the anticorrosive agent is used as the zinc-based metal of the metal material to be treated. First, the coated or uncoated steel is applied, and then a rust-proof coating agent B consisting of an aqueous resin and water is applied. The coating agent A can optionally contain water-dispersible silica, and the coating agent B can further contain at least one of phosphate ions and water-dispersible silica.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
In the present invention, the thiocarbonyl group-containing compound is a thiocarbonyl group (1) represented by the following formula:
[0027]
[Chemical Formula 3]

[0028]
In addition, a compound capable of releasing a thiocarbonyl group-containing compound in an aqueous solution or in the presence of an acid or an alkali can also be included. Representative examples of the thiocarbonyl group-containing compound include those represented by the formula (3)
[0029]
[Formula 4]

[0030]
And the like, for example, methylthiourea, dimethylthiourea, ethylthiourea, diethylthiourea, diphenylthiourea, thiopental, thiocarbazide, thiocarbazone, thiocyanuric acid, thiohydantoin, 2-thiouramil, 3-thiourazole, etc .; Formula (4)
[0031]
[Chemical formula 5]

[0032]
(Wherein R represents, for example, —H, —CH_Three, -CH₂CH_Three, -C₆H_Five, -C₈H_Five, C_FiveH_ThreeSO, etc.), for example, thioformaldehyde, thiocarbostyril, thiosaccharin, etc .; formula (5)
[0033]
[Chemical 6]

[0034]
(Wherein R represents, for example, —H, —CH_ThreeFor example, thioformaldehyde, thioacetaldehyde, etc .; formula (6)
[0035]
[Chemical 7]

[0036]
(Wherein R represents, for example, —CH_Three, -C₆H_FiveFor example, thioacetic acid, thiobenzoic acid, dithioacetic acid, etc .; formula (7)
[0037]
[Chemical 8]

[0038]
And other compounds having the structure of the formula (1), such as thiocoumazone, thiocumothiazone, thionine blue J, thiopyrone, thiopyrine, thiobenzophenone, and the like. Among these compounds, those which are not directly dissolved in water are once dissolved in an alkaline solution and then blended in the rust-proof coating agent.
[0039]
Here, when the thiocarbonyl group-containing compound in the anticorrosive coating agent is less than 0.2 g / l, the corrosion resistance is insufficient, while when it exceeds 200 g / l, the corrosion resistance is saturated and uneconomical.
[0040]
When the vanadate compound is less than 0.1 g / l, the corrosion resistance is insufficient, while when it exceeds 100 g / l, the corrosion resistance is saturated and uneconomical.
[0041]
Vanadate compounds include vanadate, vanadate, ammonium vanadate, sodium vanadate, potassium vanadate, strontium vanadate, sodium hydrogen vanadate, etc. Can be supplied in form.
[0042]
In addition, phosphate ions form a phosphate layer on the metal substrate, passivated and significantly improve the adhesion between the resin layer and the substrate, further promote the crosslinking reaction of the resin film derived from the aqueous resin, By forming a dense rust preventive film, the rust prevention property is further improved. When the phosphate ion content is less than 0.1 g / l, the antirust effect is not sufficiently exhibited. On the other hand, when it exceeds 100 g / l, the corrosion resistance is saturated and uneconomical. In the case of adding to the aqueous solution (coating agent B), if it exceeds 5 g / l, the resin gels and cannot be applied depending on the aqueous resin used. Accordingly, the phosphate ion content is 0.1 to 100 g / l for coating agent A and 0.1 to 5 g / l for coating agent B.
[0043]
Phosphate ion sources supplying phosphate ions include orthophosphoric acid, condensed phosphorus, orthophosphates or condensed phosphates of various metals, phosphorus pentoxide, phosphate minerals, commercially available complex phosphate pigments, or These mixtures are mentioned. Some orthophosphates mentioned here include their monohydrogen salt (HPO)._Four ^2-Salt), dihydrogen salt (H₂PO_Four ^-Salt). In addition, hydrogen phosphate is included in the condensed phosphate. Further, the condensed phosphate includes metaphosphate, and includes ordinary polyphosphate and polymetaphosphate. Specific examples of these phosphorus compounds include phosphate minerals such as monetite, tolufilite, witrockite, xenotime, starcolite, struvite, orbite, and commercially available composite phosphate pigments such as silica polyphosphate. Etc., complex phosphates such as pyrophosphate, metaphosphate, complex phosphates such as metaphosphate, tetrametaphosphate, hexametaphosphate, pyrophosphate, acidic pyrophosphate, tripolyphosphate, or these Of the mixture. The metal species forming the phosphate is not particularly limited, and examples thereof include alkali metals, alkaline earth metals, metal species of other typical elements, and transition metals. Examples of preferable metal species include magnesium, calcium, strontium, barium, titanium, zirconium, manganese, iron, cobalt, nickel, zinc, aluminum, lead, tin and the like. In addition, oxo cations such as vanadyl, titanyl, zirconyl and the like are also included. Particularly preferred are calcium and magnesium.
[0044]
Corrosion resistance is further improved by adding water-dispersible silica to the rust-preventive coating agent according to the present invention. In addition to the corrosion resistance, the drying property, scratch resistance, and coating film adhesion can also be improved.
[0045]
In the present invention, the water-dispersible silica is a generic term for silica having a fine particle size and having a characteristic that a stable state can be maintained when it is dispersed in water and no semi-permanent settling is observed. is there. The water-dispersible silica is not particularly limited as long as it has few impurities such as sodium and is weakly alkaline. For example, commercially available silica gel such as “Snowtex N” (manufactured by Nissan Chemical Industries), “Adelite AT-20N” (manufactured by Asahi Denka Kogyo Co., Ltd.), or commercially available Aerosil powdered silica particles can be used.
[0046]
The content of the water-dispersible silica is preferably 10 to 300 g / l for the coating agent A containing no resin and 50 to 500 g / l for the coating agent B containing the resin in 1 liter of the anticorrosive coating agent, When the content is less than these lower limits, the effect of improving the corrosion resistance is insufficient. On the other hand, when the upper limit is exceeded, the corrosion resistance is saturated and uneconomical.
[0047]
In order to improve the affinity between the aqueous resin, silica particles, and pigment (which may be blended as an optional component), and further improve the adhesion between the aqueous resin and the zinc oxide or iron oxide layer You may mix | blend a silane coupling agent or its hydrolysis condensate, or both. Here, the “hydrolysis condensate of silane coupling agent” refers to an oligomer of a silane coupling agent hydrolyzed using a silane coupling agent as a raw material.
[0048]
The silane coupling agent that can be used in the present invention is not particularly limited, but preferred examples include the following: vinyl methoxy silane, vinyl trimethoxy silane, vinyl ethoxy silane, vinyl triethoxy. Silane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, N- (1,3-dimethylbutylidene) -3 -(Triethoxysilyl) -1-propanamine, N, N'-bis [3- (trimethoxysilyl) propyl] ethylenediamine, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- ( β-aminoethyl) -γ-aminopropyltrime Xysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, N- [ 2- (Vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane.
[0049]
Particularly preferred silane coupling agents are vinyltrimethoxysilane, vinylethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxy. Silane, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, and N, N′-bis [3- (trimethoxysilyl) propyl] ethylenediamine. These silane coupling agents may be used alone or in combination of two or more.
[0050]
In the present invention, the silane compound is used at a concentration of 0.02 to 100 g in 1 liter of an aqueous solution. When the addition amount of the silane compound is less than 0.02 g, a decrease in the addition effect is recognized, and when it exceeds 100 g, the storage stability is lowered, which is not preferable.
[0051]
The antirust coating agent B of the present invention contains an aqueous resin. In the present invention, the aqueous resin includes, in addition to water-soluble resins, those that are insoluble in water but are in a state in which insoluble resins are finely dispersed in water, such as emulsions and suspensions. Examples of resins that can be used as such water-based resins include polyolefin resins, polyurethane resins, acrylic resins, polycarbonate resins, epoxy resins, polyester resins, alkyd resins, phenol resins, and other thermosetting resins. These resins can be exemplified, and a crosslinkable resin is more preferable. Particularly preferred resins are polyolefin resins, polyurethane resins, and mixed resin systems of both. Two or more aqueous resins may be mixed and used.
[0052]
The anticorrosive coating agent B containing the resin of the present invention is a composition comprising, as a main component, 1 to 80 parts by weight of water resin (including water-soluble resin and water-dispersible resin) and 99 to 20 parts of water. In one liter of the composition, 0.1 to 5 g, preferably 0.1 to 3 g of phosphate ions, and 50 to 500 g, preferably 100 to 400 g of water-dispersible silica are optionally contained.
[0053]
Further, the coating agent B of the present invention may further contain other components. Examples thereof include pigments and surfactants.
[0054]
Examples of the pigment include titanium oxide (TiO₂), Zinc oxide (ZnO), zirconium oxide (ZrO), calcium carbonate (CaCO)_Three), Barium sulfate (BaSO)_Four), Alumina (Al₂O_Three), Kaolin clay, carbon black, iron oxide (Fe₂O_Three, Fe_ThreeO_FourInorganic pigments such as) and organic pigments can be used.
[0055]
In order to improve the film forming property of the aqueous resin and form a more uniform and smooth coating film, a solvent may be used for the anticorrosive coating agent B containing the resin of the present invention. The solvent is not particularly limited as long as it is generally used in paints, and examples thereof include alcohol-based, ketone-based, ester-based, and ether-based solvents.
[0056]
In the present invention, the above rust preventive coating agents A and B are used as a rust preventive coating agent for a metal material such as zinc-coated steel or uncoated steel, and the metal material is subjected to a rust preventive treatment. In this rust prevention treatment, first, a rust preventive coating agent A that does not contain a resin is applied to the article to be coated, then the article to be coated is heated and dried with hot air, and then a rust preventive coating agent B that contains a resin is applied, It can be carried out by heating and drying.
[0057]
The heating temperature is suitably 50 to 250 ° C. in both the layer not containing the resin (first layer) and the layer containing the resin (second layer). If it is less than 50 ° C., the evaporation rate of water is slow and sufficient film formability cannot be obtained, so that the rust prevention power is insufficient. On the other hand, when the temperature exceeds 250 ° C., particularly in the case of a system including a resin, thermal decomposition of the aqueous resin occurs, so that the salt spray resistance test and water resistance are deteriorated and the appearance is also yellowed. Is done. The drying time when the object to be coated is heated with hot air after application and dried is preferably 1 second to 5 minutes.
[0058]
In the above rust prevention treatment, the adhesion amount of the rust prevention coating agent of the present invention is 5 mg / m for the first layer (layer by the coating agent A).²The above is desirable. 5mg / m²If it is less than the range, the adhesion and corrosion resistance of the second layer (layer by the coating agent B) will be insufficient. On the other hand, the upper limit is preferably 100 mg / m.²Is good. If the adhesion amount is too large, the effect as a paint base treatment is saturated and it is uneconomical, more preferably 5 mg / m.²~ 50mg / m²It is. A coating method is not particularly limited, and the coating is performed by a dipping method, a coater coating method, a spray coating method, or the like. After the application, the object to be coated is heated in a hot air furnace, a direct furnace, an IH furnace or the like and dried.
[0059]
As for the coating film thickness of the anticorrosive coating agent B of the second layer, the dry film thickness is desirably 0.1 μm or more. If it is less than 0.1 μm, the rust prevention power is insufficient. On the other hand, if the dry film thickness is too thick, problems such as cracks during processing occur, which is uneconomical, so it is preferably 20 μm or less, more preferably 0.1 to 10 μm. The application method is not particularly limited, and it can be applied by commonly used roll coating, air spray, airless spray, dipping or the like. After the application, the object to be coated is heated in a hot air furnace, a direct furnace, an IH furnace or the like and dried.
[0060]
As described above, the materials coated with the anticorrosive coating agent of the present invention are zinc-based metal-coated steel and uncoated steel. Specifically, the zinc-based metal-coated steel refers to a steel material on which zinc plating, zinc and alloy plating composed of one or more of Fe, Ni, Co, Cr, Mg, Al, Si, Mn and the like are applied. Further, similar effects can be obtained with Al-coated steel. Specifically, the Al-coated steel refers to a steel material that has been subjected to Al plating or alloy plating of Al and one or more of Si, Mg, Mn, Fe, Ni, Co, Cr, and the like. The plating method is not particularly limited, and any of electroplating method, hot dipping method, vacuum plating method and the like may be used. Although it does not specifically limit as steel materials, Steel materials, such as a cold-rolled steel plate, a hot-rolled steel plate, a thick plate, a bar steel, and a steel pipe, may be sufficient.
[0061]
The anticorrosive coating agent of the present invention can be used as a coating ground treatment agent and a water-based anticorrosive paint as described above, and can also be applied as a so-called primary antirust agent.
Furthermore, it can be used not only for the base treatment and coating base treatment of the lubricating film of galvanized steel sheets in the field of coil coating, but also for lubricating steel sheets by adding wax to the rust preventive coating agent containing the resin of the present invention. It can also be used as a lubricant and rust preventive.
[0062]
Next, the present invention will be further described with reference to examples. In the following examples, the concentration expressed in g / l means the content (g) of each component contained in 1 liter of the anticorrosive coating agent.
In each of the following examples, the corrosion resistance was evaluated by the following method.
[0063]
〔Evaluation methods〕
(A) Rust prevention
a) Preparation of specimen
The anti-corrosion coating agent A not containing the resin of the present invention is applied to a commercially available electrogalvanized steel sheet EG-MO material with a bar coat # 3 of 30 mg / m.²And then dried so that the ultimate plate temperature (PMT) is 70 ° C., and after air cooling, the rust preventive coating agent B containing the resin of the present invention is dried by bar coating # 3 to a dry film thickness of 1 μm. After coating, the PMT was dried to 150 ° C.
[0064]
b) Salt spray test
By the test method based on JIS Z2371, 5% salt solution was sprayed on the surface of the object to be coated at 35 ° C., and the degree of white rust after 240 hours was evaluated on a 10-point scale. Evaluation was performed on both the flat portion and the Erichsen 7 mm extruded portion. The evaluation criteria were as follows.

[0065]
(B) Top coat adhesion
a) Preparation of specimen
The anti-corrosion coating agent A not containing the resin of the present invention is applied to a commercially available electrogalvanized steel sheet EG-MO material with a bar coat # 3 of 30 mg / m.²After being applied so that the PMT is 70 ° C., after air-cooling, the anticorrosive coating agent B containing the resin of the present invention was applied with a bar coat # 3 so that the dry film thickness was 1 μm, PMT was dried to 150 ° C. After drying, Super Rack 100 (manufactured by Nippon Paint Co., Ltd .; acrylic melamine paint) was applied by bar coating so as to have a dry film thickness of 20 μm, and then dried at PMT 150 ° C. for 20 minutes to prepare a topcoat adhesion test plate.
[0066]
b) Primary adhesion test
Cross cut: The tape peelability of the part with a cut of 1 mm of cross cut was evaluated, and it was evaluated with a maximum of 10 points according to the following criteria.
Eriksen 7 mm: A tape was applied to the portion extruded to 7 mm with Eriksen, and the tape peelability was similarly evaluated.
Cross-cut + Eriksen 7mm: Tape was applied to the part where the cut of 1mm cross-cut was extruded to 7mm with Erichsen, and the tape peelability was similarly evaluated.
The evaluation criteria were as follows.

[0067]
c) Secondary adhesion test
After the test plate was immersed in boiling water for 30 minutes, the same test and evaluation as the primary test were performed.
[0068]
Example 1
Dissolve ammonium phosphate in pure water so that the phosphate ion is 0.1 g / l, stir and disperse with a disper for 30 minutes, and adjust to pH 8.0 to obtain the first layer of anti-corrosive coating agent A. Obtained. On the other hand, polyolefin-based resin “HITEC S-7024” (trade name; manufactured by Toho Chemical Co., Ltd.) is added to pure water so that the concentration of resin solids is 20% by weight, and stirred and dispersed with a disper for 30 minutes. The second layer of anti-corrosive coating agent B was obtained by adjusting the pH to 8.0. In order to evaluate the obtained anti-corrosion coating agent for primary anti-corrosion property and top coating adhesion, as described in the above evaluation method, a commercially available electrogalvanized steel sheet “EP-MO” (Nippon Text Panel Co., Ltd.) Manufactured, 70 × 150 × 0.8 mm) and dried. The electrogalvanized steel sheet was subjected to the above evaluation after degreasing, washing with water and drying with an alkaline degreasing agent ("Surf Cleaner 53", manufactured by Nippon Paint Co., Ltd.). Table 1 shows the composition of the anticorrosive coating agents A and B used, the amount of adhesion thereof, and the film thickness, and Table 3 shows the evaluation results.
(Examples 2 to 41)
In Example 1, the addition amount of phosphate ions in the first layer, the type and addition amount of the thiocarbonyl group-containing compound, the addition amount of Snowtex-N (water-dispersible silica), the addition amount of the vanadate compound, The same evaluation as in Example 1 was performed by changing the type of the water-soluble resin of the second layer, the addition amount of phosphate ions, and the addition amount of Snowtex-N as shown in Tables 1 to 3, respectively. The results shown in 5-7 were obtained. In Examples 34 to 41, the following silane compound (silane coupling agent) was used.
A: Vinyltrimethoxysilane
B: Vinylethoxysilane
C: 3-aminopropyltriethoxysilane
D: 3-Glycidoxypropyltrimethoxysilane
E: 3-methacryloxypropyltrimethoxysilane
F: 3-mercaptopropyltrimethoxysilane
G: N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine
H: N, N'-bis [3- (trimethoxysilyl) propyl] ethylenediamine
(Comparative Examples 1-8)
The results shown in Table 8 were evaluated in the same manner as in Example 1, except that the phosphate ion concentration, thiourea, Snowtex-N, and vanadate compound concentration were changed as shown in Table 4 in Example 1. Got.
[0069]
[Table 1]

[0070]
[Table 2]

[0071]
[Table 3]

[0072]
[Table 4]

[0073]
[Table 5]

[0074]
[Table 6]

[0075]
[Table 7]

[0076]
[Table 8]

[0077]
【The invention's effect】
As described above, according to the rust prevention treatment method of the present invention, excellent rust prevention properties can be obtained. In addition, any of the components used in the anticorrosive coating agent of the present invention has low toxicity. Therefore, according to the present invention, a non-chromium anticorrosive treatment having low pollution and excellent antirust performance can be performed.
Moreover, since the coating film is formed on the rust-proofing metal material treated by the rust-proofing method of the present invention, the generation of rust can be effectively suppressed.

Claims (4)

In 1 liter of aqueous solution on zinc-based metal-coated steel or uncoated steel that has been plated with zinc or alloy plated with one or more of zinc, Fe, Ni, Co, Cr, Mg, Al, Si, Mn After coating rust preventive coating agent A containing 0.1 to 100 g of phosphate ion, 0.2 to 200 g of thiocarbonyl group-containing compound, and 0.1 to 100 g of vanadate compound, aqueous resin and water Coating the anti-corrosion coating agent B of the composition containing as a main component, the thiocarbonyl group-containing compound is thiourea , and the coating amount of the coating layer by the coating agent A is 5 mg / m ² or more and 100 mg / m Rust prevention treatment method characterized by being less than ² .   The method according to claim 1, wherein the coating agent A further contains 10 to 300 g / l of water-dispersible silica.   The coating agent B further contains at least one of 0.1 to 5 g of phosphate ions and 50 to 500 g of water-dispersible silica in 1 liter of the composition mainly composed of the aqueous resin and water. The method according to 1 or 2. Billing has been treated by the method according to any one of claim 1 to 3, anticorrosive-treated metal material, wherein the thickness of the coating layer by co computing agent B is 0.1 to 10 [mu] m.