JP4846118B2

JP4846118B2 - Pigment for corrosion prevention coating composition and corrosion prevention coating composition using the same

Info

Publication number: JP4846118B2
Application number: JP2001105147A
Authority: JP
Inventors: 利幸野間口; 洋中山; 敦司安藤; 泰史三吉
Original assignee: Nippon Steel Nisshin Co Ltd
Current assignee: Nippon Steel Nisshin Co Ltd
Priority date: 2000-05-29
Filing date: 2001-04-03
Publication date: 2011-12-28
Anticipated expiration: 2021-04-03
Also published as: JP2002053769A

Description

【０００１】
【発明の属する技術分野】
本発明は、腐食防止被覆組成物用顔料及びそれを用いた腐食防止被覆組成物、特に亜鉛合金めっき鋼用に適し、とりわけ該鋼板の溶接部や切断面に対する防錆性に優れた、鋼材やその構造物等の防食用に好適な、環境保全上優れた腐食防止被覆組成物に関する。
【０００２】
【従来の技術】
防食や防錆、例えば鋼材の防食、防錆等には基材に対し種々の腐食防止被覆組成物が施用されており、中でも塗料、例えばジンクリッチ塗料に代表される、粉粒体や微小フレーク等の形態の亜鉛末を含有させた塗料等が多用されている。この亜鉛末含有塗料は亜鉛が鉄よりも電気的に卑である、すなわちイオン化傾向が大きく酸化されやすいのを利用して亜鉛を徐々に消耗させながら該塗料で塗被された鋼材を保護するものである。
また、亜鉛末含有塗料等の腐食防止被覆組成物としては溶媒に有機溶剤を用いた有機溶剤系のものが多く用いられてきたが、近年、環境保全、作業性改善、省資源等の観点から溶媒に水又はそれを主体に用いた水系のものが強く要望されてきている。
このような水系腐食防止被覆組成物としては、水系亜鉛末含有塗料、例えばケイ酸塩やコロイダルシリカ等のケイ酸成分を配合させたもの等が種々提案されているが（例えば、特開昭５２−１４４０３５号、特開平５−２４７３８１号等）、これらについては依然として防錆性が十分ではなく、十分実用性に耐えうるものではない。
また、腐食防止被覆組成物には、通常防錆顔料などの種々の顔料が配合されており、亜鉛末と他の顔料粉末との併用も試みられているが〔例えばモリブデン含有顔料（特開平５−３３９５２１号公報）、リン酸塩系顔料や長石（特開平６−２００１８８号公報）、酸化第二鉄及びモリブデン化合物（特開平８−６００３９号公報）、非水環状メタリン酸アルミニウム（特開平１１−１１６８５６号公報）を用いたもの等〕、水系腐食防止被覆組成物用の顔料としては未だ十分に満足しうるものではない。
【０００３】
【発明が解決しようとする課題】
本発明は、このような従来の腐食防止被覆組成物のもつ欠点を克服し、特に亜鉛合金めっき鋼用として、防錆性に優れた塗膜を与える腐食防止被覆組成物、中でも水系腐食防止被覆組成物、及び該組成物用として適した顔料を提供することを目的としてなされたものである。
【０００４】
【課題を解決するための手段】
本発明者らは、前記した好ましい特性を有する腐食防止被覆組成物や該組成物用顔料を開発するために種々研究を重ねた結果、亜鉛末及び水性アルミニウム顔料を含有して成る顔料が腐食防止被覆組成物用に適合すること、及び該顔料を水性塗料液、中でもコロイダルシリカ複合体エマルションを結着剤とする水性塗料液に用いることにより、その目的を達成しうることを見出し、この知見に基づいて本発明を完成するに至った。
【０００５】
すなわち、本発明は、
（１）亜鉛末及び水性アルミニウム顔料を含有して成る腐食防止被覆組成物用顔料（以下本発明顔料ともいう）、
（２）（Ａ）水性塗料液、（Ｂ）亜鉛末及び（Ｃ）水性アルミニウム顔料を含有して成る腐食防止被覆組成物（以下本発明被覆組成物Ｉともいう）、
及び
（３）（Ａ）水性塗料液、（Ｂ）亜鉛末、（Ｃ）水性アルミニウム顔料及び（Ｄ）体質顔料及び／又は防錆顔料を含有して成る腐食防止被覆組成物（以下本発明被覆組成物ＩＩともいう）、
を提供するものである。
なお、本発明被覆組成物Ｉ及び本発明被覆組成物ＩＩを総称して本発明被覆組成物という。
【０００６】
【発明の実施の形態】
本発明の好ましい態様としては、
（４）亜鉛末と水性アルミニウム顔料との割合が質量比で９０：１０〜９９．８：０．２の範囲である前記（１）記載の腐食防止被覆組成物用顔料、
（５）さらに防錆顔料及び／又は体質顔料を含有して成る前記（１）又は（４）記載の顔料、
（６）防錆顔料がリン酸塩系のものである前記（５）記載の顔料、
（７）防錆顔料がモリブデン酸塩系のものである前記（５）又は（６）記載の顔料、
（８）体質顔料がタルク、酸化亜鉛、炭酸カルシウム、マイカ、硫酸バリウムである前記（５）、（６）又は（７）記載の顔料、
（９）亜鉛末、水性アルミニウム顔料、及び防錆顔料及び／又は体質顔料相互間の割合がそれぞれ７５〜９７質量％、０．２〜８．３質量％及び０．１〜２０質量％の範囲である前記（５）ないし（８）のいずれかに記載の顔料、
（１０）（Ａ）成分における不揮発分量と、（Ｂ）成分及び（Ｃ）成分の合計量との質量比が１：４〜１：３５であり、かつ（Ｂ）成分と（Ｃ）成分との割合が質量比で９０：１０〜９９．８：０．２の範囲である前記（２）記載の腐食防止被覆組成物、
（１１）（Ａ）成分の水性塗料液が含ケイ素無機結着剤系、コロイダルシリカ複合体系、アクリル樹脂系及びポリウレタン樹脂系の中から選ばれた少なくとも１種のものである前記（２）、（３）又は（１０）記載の腐食防止被覆組成物、
（１２）コロイダルシリカ複合体系水性塗料液がコロイダルシリカ複合体エマルションを結着剤とするものである前記（１１）記載の腐食防止被覆組成物、
（１３）（Ａ）成分における不揮発分量と、（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分の合計量との質量比が１：４〜１：３５であり、かつ（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分相互間の割合がそれぞれ７５〜９７質量％、０．２〜８．３質量％及び０．１〜２０質量％の範囲である前記（３）、（１１）又は（１２）記載の腐食防止被覆組成物、
（１４）（Ａ′）コロイダルシリカ複合体エマルションを結着剤とする水性塗料液、（Ｂ）亜鉛末、（Ｃ）水性アルミニウム顔料及び（Ｄ）体質顔料及び／又は防錆顔料を含有して成る腐食防止被覆組成物、
（１５）（Ａ′）成分における不揮発分中のコロイダルシリカの含有割合が１０〜８０質量％であり、しかも（Ａ′）成分における不揮発分量と、（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分の合計量との質量比が１：４〜１：３５であり、かつ（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分相互間の割合がそれぞれ７５〜９７質量％、０．２〜８質量％及び２〜２０質量％の範囲である前記（１４）記載の腐食防止被覆組成物、
（１６）防錆顔料がリン酸塩系のものである前記（３）、又は（１１）ないし（１５）のいずれかに記載の組成物、
（１７）防錆顔料がモリブデン酸塩系のものである前記（３）、又は（１１）ないし（１６）のいずれかに記載の組成物、
（１８）体質顔料がタルク、酸化亜鉛、炭酸カルシウム、マイカ、硫酸バリウムである前記（３）、又は（１１）ないし（１７）のいずれかに記載の組成物、
が挙げられる。
【０００７】
本発明顔料は、亜鉛末と水性アルミニウム顔料を含有し、場合によりさらに防錆顔料及び／又は体質顔料すなわち防錆顔料と体質顔料の両方又はいずれか一方を含有していてもよいが、防錆顔料を含有させるのが好ましい。
【０００８】
亜鉛末は、腐食防止被覆組成物、中でも塗料組成物に通常用いられているものであれば特に制限はなく、亜鉛、又は亜鉛を主体とする合金すなわち亜鉛基合金の粉末や微小フレーク等が用いられるが、好ましくは平均粒径２〜１５μｍ、中でも２〜８μｍの粉末や、平均直径３〜３０μｍ、厚さ０．５〜２μｍのフレークが沈降性が良好であり、塗装作業上好ましい。
【０００９】
水性アルミニウム顔料は、水性腐食防止被覆組成物、中でも水性塗料組成物用に適するように水性化処理されたアルミニウム顔料であって、一般的には粉末状やフレーク状のアルミニウム顔料に水性化表面処理が施されたものであり、その使用形態については特に制限されないが、ペースト状あるいは乾燥粉末状とするのがよい。水性化表面処理に用いられる処理剤としては、例えばリン酸、リン酸モノエステルやリン酸ジエステルなどのリン酸エステル又はそのアミン付加物、高級脂肪酸の重合物（例えばダイマー、トリマー）などが挙げられる。ペースト状とするには有機溶剤、好ましくはミネラルスピリット、ソルベントナフサ、トルエン、キシレン、特にミネラルスピリットあるいはそれとソルベントナフサ、トルエン又はキシレンとの混合溶剤が用いられる。
【００１０】
体質顔料については、腐食防止被覆組成物、中でも塗料組成物に通常用いられているものであれば特に制限はなく、例えばシリカ、タルク、クレー、カオリン、マイカ、亜鉛華、硫酸バリウム、炭酸カルシウム、アルミナ、酸化亜鉛、炭酸マグネシウム、炭酸バリウム、ベントナイトなどが挙げられるが、好ましくはタルク、酸化亜鉛、炭酸カルシウム、マイカ、硫酸バリウムが用いられる。
【００１１】
防錆顔料については、腐食防止被覆組成物、中でも塗料組成物に通常用いられているものであれば特に制限はなく、例えばクロム系顔料、鉛系顔料、ホウ酸塩系顔料、リン酸塩系顔料、モリブデン酸塩系顔料などが挙げられるが、好ましくは防錆性を一層向上させうるのでリン酸塩系顔料やモリブデン酸塩系顔料が用いられる。
このリン酸塩系顔料としては、例えばリン酸亜鉛、リン酸アルミニウム、リン酸カルシウム、リン酸アルミニウム亜鉛、リン酸カルシウム亜鉛、リン・ケイ酸亜鉛、亜鉛処理されたポリリン酸アルミニウムなどが、またモリブデン酸塩系顔料としては、モリブデン酸カルシウム、リンモリブデン酸アルミニウム、モリブデン酸亜鉛、モリブデン酸亜鉛カルシウム、リンモリブデン酸亜鉛などがそれぞれ挙げられる。
【００１２】
本発明顔料における各顔料相互間の含有割合については、亜鉛末と水性アルミニウム顔料とでは質量比で９０：１０〜９９．８：０．２の範囲とするのが好ましい。
さらに防錆顔料や体質顔料を含有させる場合には、亜鉛末、水性アルミニウム顔料、及び防錆顔料及び／又は体質顔料相互間の割合はそれぞれ７５〜９７質量％、０．２〜８．３質量％及び０．１〜２０質量％、中でも７５〜９７質量％、０．３〜８質量％及び２〜２０質量％、特に７５〜９７質量％、０．３〜５質量％及び２．７〜２０質量％の範囲とするのが好ましい。
このような割合とすることにより、後述するように本発明顔料を用いた本発明被覆組成物の性能を向上させることができる。
【００１３】
本発明被覆組成物は、上記本発明顔料と水性塗料液を含有して成るもの、すなわち（Ａ）水性塗料液、（Ｂ）亜鉛末、及び（Ｃ）水性アルミニウム顔料及び場合により用いられる（Ｄ）体質顔料及び／又は防錆顔料を含有して成るものであるが、防錆顔料を含有させるのが好ましい。
【００１４】
本発明被覆組成物において、その組成成分の（Ａ）成分の水性塗料液としては、例えば含ケイ素無機結着剤系、コロイダルシリカ複合体系、ポリウレタン樹脂系、アクリル樹脂系、ポリエステル樹脂系、アルキド樹脂系、エポキシ樹脂系、ビニル樹脂系、不飽和ポリエステル樹脂系、紫外線硬化樹脂系、フッ素樹脂系、メラミン樹脂系のもの等が挙げられ、中でも含ケイ素無機結着剤系、コロイダルシリカ複合体系、ポリウレタン樹脂系及びアクリル樹脂系の中から選ばれた少なくとも１種のものが好ましい。
【００１５】
この（Ａ）成分の水性塗料液に用いられる結着剤としては、例えば含ケイ素無機結着剤、コロイダルシリカ複合体、ポリウレタン樹脂系、アクリル樹脂系、ポリエステル樹脂系、アルキド樹脂系、エポキシ樹脂系、ビニル樹脂系、不飽和ポリエステル樹脂系、紫外線硬化樹脂系、フッ素樹脂系又はメラミン樹脂系等が挙げられ、中でもコロイダルシリカ複合体とりわけそのエマルション、含ケイ素無機結着剤、ポリウレタン樹脂系及びアクリル樹脂系の中から選ばれた少なくとも１種が好ましい。これらには変性物、例えばシリコーン変性アクリル樹脂系結着剤なども包含される。
【００１６】
これらの結着剤のうち、コロイダルシリカ複合体としては、エマルションとしたものが好ましい。
コロイダルシリカ複合体エマルションについては塗料組成物に通常用いられているものであれば特に制限されないが、好ましくはコロイダルシリカの存在下に、乳化重合しうる１種又は２種以上の単量体を乳化重合させることによって得られたものやこのような単量体の乳化重合物を含有する水性エマルションにコロイダルシリカを配合分散させたもの、例えば単独重合型や共重合型のアクリル系エマルションやジエン系エマルションなどが挙げられる。その１例としては、コロイダルシリカとスチレン−アクリロニトリル共重合体とを均一に分散させた水性エマルションが挙げられる。
【００１７】
また、含ケイ素無機結着剤としては、ケイ酸アルカリ、中でもケイ酸アンモニウムやアルカリ金属ケイ酸塩や、ケイ酸エステルの加水分解縮合物が好ましく、また、これらはアクリル樹脂系等の適当な樹脂とともにエマルションとして用いてもよい。
【００１８】
また、ポリウレタン樹脂系結着剤としては、湿気硬化型やブロックイソシアネート硬化型やラッカー型等の一液型のもの、中でもカルボキシル基やエステル基を含有するものが好ましい。
このうち、カルボキシル基含有ポリウレタン樹脂系結着剤は、中和により水に安定に分散又は溶解するものであればよく、このようなものは、例えばカルボキシル基をもつ多価アルコール、多価アルコール及び多価イソシアネート化合物を、必要に応じ鎖長調整剤を用い、常法で反応させることにより得られる。
カルボキシル基をもつ多価アルコールとしてはグルコン酸、ジメチロール酢酸、ジメチロールプロピオン酸、ジメチロール酪酸、ジヒドロキシコハク酸、無水フタル酸等の酸無水物とグリセリン等の３価アルコールとの半エステル化物等が、多価アルコールとしてはトリメチロールプロパン、エチレングリコール、プロピレングリコール、ブタンジオール、ヘキサンジオール、トリメチレングリコール、ジエチレングリコール、ヘキシレングリコール、オクチレングルコール、ネオペンチルグリコール、水素化ビスフェノールＡ、ポリエステルポリオール、アクリルポリオール、ポリカーボネートポリオール等が、多価イソシアネート化合物としてはヘキサメチレンジイソシアネート、トリレンジイソシアネート、イソホロンジイソシアネート、ジフェニルメタン‐４，４′‐ジイソシアネート、トランス‐シクロヘキサ‐１，４‐ジイソシアネート、ｍ‐キシレンジイソシアネート、ナフタレンジイソシアネート、ｐ‐フェニレンジイソシアネート、４，４′‐ジフェニルメタントリイソシアネート等のポリイソシアネート自体からなる単独のものや、このようなポリイソシアネートとポリオール、例えばポリプロピレンエーテルポリオール、ポリエチレン・プロピレンエーテルポリオールあるいはポリエステルポリオールとの反応生成物としての遊離イソシアネート基含有ウレタンプレポリマーや、カルボジイミド化等で液状化されたポリイソシアネート等の変性ポリイソシアネート等が、鎖長調整剤としてはエチレンジアミン、トリレンジアミン、イソホロンジアミン、プロピレンジアミン、キシレンジアミンのようなジアミン等がそれぞれ挙げられる。
カルボキシル基含有ポリウレタン樹脂系結着剤は、その分子量が５０００〜２，０００，０００、中でも１０，０００〜１，０００，０００の範囲であるのが、またその酸価が１０〜５０の範囲であるのが適当である。分子量が小さすぎると耐水性が低下するし、また大きすぎると可撓性が低下する。また、酸価が小さすぎると安定性が低下するし、また大きすぎると耐水性が低下する。
カルボキシル基又はエステル基含有ポリウレタン樹脂系結着剤には市販品、例えば三井化学社製のＵＤ５００，ＵＤ１００Ｎ、第一工業製薬社製のスーパフレックス、大日本インキ化学工業社製のボンディック、日本エヌエスシー社製の７Ｘ８０１，７Ｘ８１３、ＩＣＩレジン社製のネオレッツ、グンゼ産業社製のサンキュア８２５，８２２Ａなども用いられる。
カルボキシル基含有ポリウレタン樹脂系結着剤を中和する際に用いられる中和剤としては、例えばアンモニア、トリメチルアミン、トリエチルアミン、トリエタノールアミン等が挙げられる。
【００１９】
また、アクリル樹脂系結着剤としては、例えばアクリル酸２‐ヒドロキシエチル、アクリル酸２‐ヒドロキシプロピル、メタクリル酸２‐ヒドロキシエチル、メタクリル酸２‐ヒドロキシプロピル、アクリル酸グリシジル又はメタクリル酸グリシジル等のホモポリマーのような（メタ）アクリル酸系樹脂や、シリコーン変性アクリル樹脂系のような変性アクリル樹脂系のものなどが挙げられる。
アクリル樹脂系結着剤は、その分子量が５，０００〜１，０００，０００、中でも１０，０００〜１，０００，０００、またその水酸基価が５〜３００、中でも１０〜２００の範囲のものが適当である。
シリコーン変性アクリル樹脂系結着剤には市販品、例えば日本エヌエスシー社製のカネビノールＫＤ７，ＫＤ１１、旭化成工業社製のポリデュレックスＧ６１３，Ｇ６２０なども用いられる。
【００２０】
本発明被覆組成物においては、（Ａ）成分における不揮発分量と、（Ｂ）成分及び（Ｃ）成分、或いは（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分の合計量との質量比が１：４〜１：３５であるのが好ましい。
さらに、本発明被覆組成物Ｉにおいては、（Ｂ）成分と（Ｃ）成分との割合が質量比で９０：１０〜９９．８：０．２の範囲、また本発明被覆組成物ＩＩにおいては、（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分相互間の割合がそれぞれ７５〜９７質量％、０．２〜８．３質量％及び０．１〜２０質量％、中でも７５〜９７質量％、０．３〜８質量％及び２〜２０質量％、特に７５〜９７質量％、０．３〜５質量％及び２．７〜２０質量％の範囲であるのが好ましい。
【００２１】
本発明被覆組成物において、（Ａ）成分における不揮発分量が、顔料成分例えば（Ｂ）成分及び（Ｃ）成分、或いは（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分からなるものの合計量に対し、上記範囲より低すぎると被膜の各種物性が低下するし、また高すぎると防食性や防錆性が低下する。
（Ｂ）成分及び（Ｃ）成分、或いは（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分の合計量に対するこれら各成分の百分比において、（Ｂ）成分の割合が上記範囲より低いと防食性や防錆性が低下し、また上記範囲より高いと白錆の発生が多くなり塗膜の耐久性が低下するし、また（Ｃ）成分の割合が上記範囲より低いと防錆性が低下し、また上記範囲より高いと付着性が低下し、かつ塗膜が脆くなるし、また場合により用いられる（Ｄ）成分の割合が上記範囲より低いと白錆の抑制効果が低下し、また上記範囲より高いと塗膜の各種物性が低下する傾向がみられる。
【００２２】
本発明被覆組成物として好ましくは、その組成成分の（Ａ）成分の水性塗料液について、基本的には結着剤としてのコロイダルシリカ複合体エマルションを適量の水で希釈、分散させたもの、中でも（Ａ′）コロイダルシリカ複合体エマルションを結着剤とする水性塗料液、（Ｂ）亜鉛末、（Ｃ）水性アルミニウム顔料及び（Ｄ）体質顔料及び／又は防錆顔料を含有して成る腐食防止被覆組成物が用いられ、この腐食防止被覆組成物は水性塗料組成物である。
この水性塗料組成物において、好適な（Ａ′）成分としては、その中の不揮発分について、不揮発分中のコロイダルシリカの含有割合が１０〜８０質量％、好ましくは２５〜６５質量％、より好ましくは３０〜５５質量％の範囲であるものが挙げられる。この割合が１０質量％未満では耐水性が低下しフクレが発生しやすくなるし、また８０質量％を超えると塗膜の各種物理特性（例えば可撓性、硬度、付着性等）が低下傾向となるので好ましくない。
【００２３】
また、水性塗料組成物の組成成分の好適配合割合については、（Ａ′）成分における不揮発分量と、（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分の合計量との質量比が１：４〜１：３５、好ましくは１：７〜１：３０、より好ましくは１：９〜１：２５の範囲であり、かつ（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分相互間の割合すなわちこれら３成分の合計量に対するこれら各成分の百分比がそれぞれ７５〜９７質量％、０．２〜８質量％及び２〜２０質量％、好ましくは７５〜９７質量％、０．３〜５質量％及び２．７〜２０質量％、より好ましくは８０〜９６質量％、０．５〜５質量％及び３．５〜１５質量％、さらに好ましくは８５〜９５質量％、１．０〜５質量％及び４．０〜１０質量％の範囲である。
（Ａ′）成分における不揮発分量が、（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分の合計量に対し、上記範囲より低すぎると塗膜の各種物性が低下するし、また高すぎると防食性や防錆性が低下する。
（Ｂ）成分、（Ｃ）成分及び（Ｄ）成分の合計量に対するこれら各成分の百分比において、（Ｂ）成分の割合が上記範囲より低いと防食性や防錆性が低下し、また上記範囲より高いと白錆の発生が多くなり塗膜の耐久性が低下するし、また（Ｃ）成分の割合が上記範囲より低いと防錆性が低下し、また上記範囲より高いと付着性が低下し、かつ塗膜が脆くなるし、また（Ｄ）成分の割合が上記範囲より低いと白錆の抑制効果が低下し、また上記範囲より高いと塗膜の各種物性が低下する傾向がみられる。
【００２４】
本発明被覆組成物には、その好適態様である上記塗料組成物を含め、本発明の目的をそこなわない範囲で、必要に応じ、塗料組成物に通常用いられる添加成分、例えば着色顔料、たれ止め剤、造膜助剤、湿潤剤、消泡剤、凍結防止剤、レベリング剤、分散剤、沈降防止剤、可塑剤、防炎剤、防カビ剤、紫外線吸収剤、酸化防止剤、塗面調整剤、界面活性剤、安定剤等を配合することができる。
着色顔料としては、例えば弁柄、チタン白、カーボンブラック、アニリンブラック、グンジョウ、カドミウムイエロー、クロムイエロー、鉛白、ウオッチングレッド、シアニンブルーなどの有機青、フタロシアニングリーンなどの有機緑等が挙げられる。
沈降防止剤としては、例えば有機ベントナイト、酸化ポリエチレン、アエロシル等が挙げられる。
【００２５】
本発明被覆組成物は、その好適態様である上記塗料組成物を含め、塗料液と、亜鉛末又はそれと所定顔料の混合物と、水性アルミニウム顔料ペーストとをそれぞれ別個にした三缶セットや、塗料液と、亜鉛末と水性アルミニウム顔料（固形粉末）の混合物又は亜鉛末と水性アルミニウム顔料と所定顔料の混合物とをそれぞれ別個にした二缶セットの形態で供するのが実用的であり、このようなセット形態の場合、所定鋼材への塗装時に上記セットの各缶成分を撹拌器等で十分に混合撹拌して均一化してから用いればよい。鋼材への塗装は、スプレー、浸漬、刷毛塗り、ロールコータなどの適当なコーターによる機械的塗工等の通常の塗装法によればよく、塗装後の乾燥は自然乾燥や熱風乾燥によればよい。
【００２６】
本発明被覆組成物は、その好適態様である上記塗料組成物を含め、特に亜鉛めっき鋼及び／又は亜鉛合金めっき鋼からなる鋼材に適用した場合に、特に該鋼材の溶接部や切断端面などの素地鋼露出部やめっき層傷付部などに対し、優れた防食性、防錆性を示す。亜鉛合金めっき鋼としては、好ましくは亜鉛−アルミニウム系合金めっき鋼、亜鉛−アルミニウム−マグネシウム系合金めっき鋼、亜鉛−アルミニウム−マグネシウム−シリコン系合金めっき鋼などが挙げられる。
また、本発明被覆組成物は、その好適態様である上記塗料組成物を含め、めっき部中にアルミニウムを含む亜鉛合金めっき鋼からなる鋼材に適用した場合に大きな効果を発揮する。この現象は十分には解明できていないが、この鋼材ではめっき部にアルミニウムが含まれているため、このめっき部と、本発明被覆組成物による水性アルミニウム顔料を含む塗装部等の被覆部との接触電位差が小さくなることによるものと推測される。
さらに、本発明被覆組成物は、その好適態様である上記塗料組成物を含め、めっき部中にアルミニウムとともにマグネシウムを含む亜鉛合金めっき鋼からなる鋼材に適用した場合により一層優れた効果が得られ、長期間にわたり塗装部からの赤錆の発生を防止することができる。この理由は十分に明らかにはなっていないが、この鋼材ではめっき部に含まれるマグネシウムが、めっき部と塗装部との接触電位差を小さくするかあるいは腐食の初期段階でめっき部中のマグネシウムがイオンや水溶性の塩となって塗装部に流れ込むことにより、塗装部の腐食が著しく抑制されるためであると推測される。
【００２７】
【実施例】
次に実施例によって本発明をさらに詳細に説明するが、本発明はこれらの例によって何ら限定されるものではない。
【００２８】
各例の塗料組成物を用いて得た塗膜の防錆性能は次のようにして評価した。
防錆性：
ＪＡＳＯＭ６０９−９１に規定する複合サイクル腐食試験（ＣＣＴ）を行い、所定サイクルごとの赤錆発生の有無や程度を調べ、次の判定基準により評価した。
○：赤錆発生率１％未満
△：赤錆発生率１％以上１０％未満
×：赤錆発生率１０％以上５０％未満
××：赤錆発生率５０％以上
なお、上記腐食試験の１サイクルは、試料に５％濃度の塩水を温度３５℃で２時間噴霧したのち、温度６０℃、湿度３０％で４時間乾燥し、次いで温度５０℃、湿度９５％で２時間湿潤処理することからなる。
【００２９】
実施例１
先ず、塗料液Ａを次のとおり調製した。
すなわち、ＱＡＳ２５（商品名、日産化学社製、コロイダルシリカ）１０質量部及びモビニール８０１０（商品名、クラリアントポリマー社製、コロイダルシリカ複合体エマルション）４０質量部からなる結着剤、ソルフィット〔商品名、クラレ社製、３‐メチル‐３‐メトキシブタノール（成膜助剤）〕４．９質量部、ベントンＥＷ（商品名、ＲＨＥＯＸ社製、ヘクトライト系増粘剤）１．０質量部、デヒドラン１６２０（商品名、サンノプコ社製、シリコーン系消泡剤）０．２質量部及びイオン交換水４１．４質量部を混合し、さらに適当なｐＨ調整剤でｐＨが１０になるようにして塗料液Ａを調製した。
次いで、この塗料液Ａ２８．２質量部に、ＬＳ−２（商品名、三井金属塗料化学社製、亜鉛末）９５．０質量部、ミクロンＡ（商品名、林化成社製、タルク）５．０質量部及びＡＷ５２０Ｂ（商品名、旭化成社製、アルミペースト）２．０質量部を加え撹拌器で十分混合撹拌を行い均一な水性塗料組成物を調製した。
【００３０】
実施例２〜１１、比較例１〜６
実施例１と同様に調製した塗料液Ａを用い、後記の表１に示すとおりの組成成分及び組成割合とし、実施例１と同様にして水性塗料組成物を調製した。
なお、表中の組成成分のうち、実施例１に示したもの以外のものについては、以下の市販品を用いた。
リン酸Ｃａすなわちリン酸カルシウム：キクチカラー社製、ＣＰ−Ｚ
モリブデン酸Ｃａすなわちモリブデン酸カルシウム：キクチカラー社製、ＬＦボウセイＭＣ−４００ＷＲ
リン酸亜鉛：三井金属社製、リン酸亜鉛Ｓ
リンモリブデン酸Ａｌすなわちリンモリブデン酸アルミニウム：キクチカラー社製、ＬＦボウセイＰＭ−３０３Ｗ
リン酸Ａｌすなわちリン酸アルミニウム系化合物：テイカ社製、Ｋ−ＷＨＩＴＥ１４０Ｗ
【００３１】
一方、供試原板は次のようにして調製した。
すなわち、７０ｍｍ×１５０ｍｍ寸法のＺｎ−５％Ａｌめっき鋼板（片面当りのめっき付着量：１８３ｇ／ｍ²、板厚：３．２ｍｍ）を２枚用意し、これら同士を短辺側で、ワイヤーにＹＧＷ−１２（商品名、大同特殊鋼社製、ＤＳ１Ａ）を用い、二酸化炭素をシールドガスとして２０リットル／分の流量で流しながら、突合せ溶接処理した。その際の処理条件は、電流１５０〜１６０Ａ、電圧２２Ｖ、溶接処理速度５０ｃｍ／分とした。
【００３２】
この原板の溶接ビード部をワイヤーブラシを用いて清浄にした後、溶接ビード部を覆って、上記各実施例及び各比較例の各水性塗料組成物を全長８０ｍｍにわたり乾燥膜厚で４０±５μｍとなるように刷毛で塗装し、２０℃、湿度６５％の室内で７日間乾燥して塗膜を得た。得られた塗膜の性能を評価した結果を表１に示す。
【００３３】
【表１】

【００３４】
これより、各比較例の塗料組成物を用いた塗膜が１００サイクルの試験で錆が発生してしまうのに対し、本発明の上記各実施例の塗料組成物を用いた塗膜はいずれも１００サイクルの試験では錆が発生せず、特に防錆顔料を用いた場合には１５０サイクルの試験でも錆が発生せず、防錆性に優れていることは明らかである。
【００３５】
実施例１２〜１４
実施例６と同様の組成成分及び組成割合の水性塗料組成物を調製し、Ｚｎ−５％Ａｌ−０．１％Ｍｇめっき鋼板（片面当りのめっき付着量：１６１ｇ／ｍ²、板厚：３．２ｍｍ）、Ｚｎ−６％Ａｌ−３％Ｍｇめっき鋼板（片面当りのめっき付着量：１５４ｇ／ｍ²、板厚：３．２ｍｍ）及びＺｎ−１１％Ａｌ−３％Ｍｇ−０．１５％Ｓｉめっき鋼板（片面当りのめっき付着量：１５８ｇ／ｍ²、板厚：３．２ｍｍ）の溶接ビード部にそれぞれ塗装して試験に供した。なお、これらの供試原板の溶接条件、塗装条件ならびに塗膜の防錆性能の評価は実施例１と同様の条件、方法で行った。得られた塗膜の性能を評価した結果を表２に示す。
【００３６】
【表２】

【００３７】
表２より明らかなように、実施例６と同様に調製した塗料組成物をマグネシウムを含有する亜鉛−アルミニウム系めっき鋼や亜鉛−アルミニウム−シリコン系めっき鋼に塗装した場合、実施例６の亜鉛−アルミニウム系めっき鋼に塗装する場合と比べさらに長期間にわたって赤錆が発生せず、極めて優れた防錆性が得られる。
【００３８】
実施例１５
先ず、塗料液Ｂを次のとおり調製した。
すなわち、オレスターＵＤ５００（商品名、三井化学社製、水性ウレタン樹脂、ＮＶ３８％）からなる結着剤５６．６質量部、Ｎ‐メチル‐２‐ピロリドンからなる成膜助剤４．０質量部、ベントンＥＷ（商品名、ＲＨＥＯＸ社製、ヘクトライト系増粘剤）１．０質量部、デヒドラン１６２０（商品名、サンノプコ社製、シリコーン系消泡剤）０．２質量部及びイオン交換水３５．７質量部を混合し、さらに適当なｐＨ調整剤でｐＨが１０になるようにして塗料液Ｂを調製した。
次いで、この塗料液２８．２質量部に、ＬＳ−２（商品名、三井金属塗料化学社製、亜鉛末）９８．０質量部及びＡＷ５２０Ｂ（商品名、旭化成社製、アルミペースト）２．０質量部を加え撹拌器で十分混合撹拌を行い均一な水性塗料組成物を調製した。
【００３９】
実施例１６
塗料液Ｂに代えて以下のようにして調製した塗料液Ｃを用いた以外は実施例１５と同様にして水性塗料組成物を調製した。
塗料液Ｃは、カネビノールＫＤ１１（商品名、日本エヌエスシー社製、アクリル・シリコーン系エマルション、ＮＶ４５％）からなる結着剤４７．８質量部、ソルフィット〔商品名、クラレ社製、３‐メチル‐３‐メトキシブタノール（成膜助剤）〕４．９質量部、ベントンＥＷ（商品名、ＲＨＥＯＸ社製、ヘクトライト系増粘剤）１．０質量部、デヒドラン１６２０（商品名、サンノプコ社製、シリコーン系消泡剤）０．２質量部及びイオン交換水４３．６質量部を混合し、さらに適当なｐＨ調整剤でｐＨが１０になるようにして調製した。
【００４０】
実施例１７〜２６、比較例７〜１１
実施例１、実施例１５又は実施例１６と同様に調製した塗料液ＡないしＣのいずれかを用い、後記の表３に示すとおりの組成成分及び組成割合とし、実施例１５と同様にして水性塗料組成物を調製した。
なお、表中の組成成分は上記したものと同じである。
【００４１】
これらの各実施例及び各比較例の各水性塗料組成物を用い、実施例１のものと同様にして得た供試原板上の塗膜の性能を前記した実施例１と同様に評価した結果を表３に示す。
【００４２】
【表３】

【００４３】
表３より、亜鉛末のみを顔料とする比較例７〜９の塗料組成物を用いた塗膜が３０サイクルの試験で錆が発生してしまうのに対し、亜鉛末とともに水性アルミニウムを顔料とする実施例１５〜２３の塗料組成物を用いた塗膜はいずれも６０サイクルの試験では錆が発生せず１５０サイクルの試験でも錆は大きくは広がらない。さらに防錆顔料を加えた実施例２４〜２６の塗料組成物を用いた塗膜は１５０サイクルの試験でも錆が発生せず、防錆性に優れていることは明らかである。
【００４４】
実施例２７〜２９
実施例２０と同様の組成成分及び組成割合の水性塗料組成物を調製し、Ｚｎ−５％Ａｌ−０．１％Ｍｇめっき鋼板（片面当りのめっき付着量：１６１ｇ／ｍ²、板厚：３．２ｍｍ）、Ｚｎ−６％Ａｌ−３％Ｍｇめっき鋼板（片面当りのめっき付着量：１５４ｇ／ｍ²、板厚：３．２ｍｍ）及びＺｎ−１１％Ａｌ−３％Ｍｇ−０．１５％Ｓｉめっき鋼板（片面当りのめっき付着量：１５８ｇ／ｍ²、板厚：３．２ｍｍ）の溶接ビード部にそれぞれ塗装して試験に供した。なお、これらの供試原板の溶接条件、塗装条件ならびに塗膜の防錆性能の評価は実施例１と同様の条件、方法で行った。得られた塗膜の性能を評価した結果を表４に示す。
【００４５】
【表４】

【００４６】
表４より明らかなように、実施例の塗料組成物が適用される鋼材としては、マグネシウムを含有する亜鉛−アルミニウム系めっき鋼や亜鉛−アルミニウム−シリコン系めっき鋼の方が、実施例２０で用いられる亜鉛−アルミニウム系めっき鋼よりもさらに長期間にわたって赤錆を発生せず、優れた防錆性を示すことから、前者の方が好ましい。
【００４７】
【発明の効果】
本発明顔料は腐食防止被覆組成物に配合することにより、該組成物にいかに示すような優れた特性を付与しうる。
本発明の腐食防止被覆組成物は、防錆性に優れ、特に防錆に有効な亜鉛末の消耗度合いを緩徐なものとすることができ、塗膜中の亜鉛末に起因する白錆の発生を抑制することができ、長期の防錆性保持が期待でき、とりわけ亜鉛めっき鋼や亜鉛合金めっき鋼用に好適である。
また、本発明の腐食防止被覆組成物は、溶媒に水を用いるか、あるいは極力有機溶剤を減らした水リッチのものであるから、公害防止や環境保全の点で優れている。
したがって、本発明の腐食防止被覆組成物は、特に亜鉛めっき鋼や亜鉛合金めっき鋼からなる鋼構造物や鋼構築物、例えば道路、橋梁、鉄道、港湾、ビル、工場、プレハブ住宅、発電所、鉄塔、遊園地、プール、その他の娯楽・アミューズメント施設等の重防食が要求される用途に好適である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pigment for a corrosion-preventing coating composition and a corrosion-preventing coating composition using the same, particularly suitable for zinc alloy-plated steel, and in particular, a steel material excellent in rust resistance against the welded portion and cut surface of the steel plate. The present invention relates to a corrosion-preventing coating composition that is suitable for anticorrosion of the structure and the like and excellent in environmental conservation.
[0002]
[Prior art]
Various anti-corrosion coating compositions are applied to the base material for anti-corrosion and anti-corrosion, for example, anti-corrosion and anti-corrosion of steel materials. Among them, powders and fine flakes represented by paints such as zinc rich paints. The paint etc. which contained the zinc powder of the form etc. are used abundantly. This zinc powder-containing paint protects the steel coated with the paint while gradually depleting zinc by utilizing the fact that zinc is electrically baser than iron, that is, it has a high ionization tendency and is easily oxidized. It is.
In addition, as an anticorrosion coating composition such as a zinc-containing paint, an organic solvent-based composition using an organic solvent as a solvent has been used in many cases. However, in recent years, from the viewpoint of environmental conservation, workability improvement, resource saving, etc. There has been a strong demand for water or a water-based solvent mainly using it as a solvent.
As such a water-based corrosion prevention coating composition, various water-based zinc dust-containing paints such as those containing a silicate component such as silicate or colloidal silica have been proposed (for example, JP-A-52). -144035, JP-A-5-247181, etc.), these products still have insufficient rust preventive properties and are not sufficiently practical.
In addition, various pigments such as rust preventive pigments are usually blended in the anticorrosion coating composition, and attempts have been made to use zinc powder in combination with other pigment powders. No. 339521), phosphate pigments and feldspars (Japanese Patent Laid-Open No. 6-2000188), ferric oxide and molybdenum compounds (Japanese Patent Laid-Open No. 8-60039), non-acyclic aluminum metaphosphate (Japanese Patent Laid-Open No. 11). No. -116856), etc.], still not fully satisfactory as a pigment for an aqueous corrosion protection coating composition.
[0003]
[Problems to be solved by the invention]
The present invention overcomes the drawbacks of such conventional corrosion-preventing coating compositions, and particularly provides corrosion-resistant coating compositions that provide coatings with excellent rust-prevention properties, particularly for zinc alloy-plated steel. The object of the present invention is to provide a composition and a pigment suitable for the composition.
[0004]
[Means for Solving the Problems]
As a result of various researches to develop a corrosion-preventing coating composition having the above-mentioned preferable characteristics and a pigment for the composition, the present inventors have found that a pigment comprising zinc dust and an aqueous aluminum pigment has a corrosion-inhibiting effect. It was found that the object can be achieved by adapting the coating composition and using the pigment in an aqueous coating liquid, particularly an aqueous coating liquid having a colloidal silica composite emulsion as a binder. Based on this, the present invention has been completed.
[0005]
That is, the present invention
(1) A pigment for a corrosion-preventing coating composition comprising zinc dust and an aqueous aluminum pigment (hereinafter also referred to as the present invention pigment),
(2) Corrosion-preventing coating composition comprising (A) an aqueous coating liquid, (B) zinc dust and (C) an aqueous aluminum pigment (hereinafter also referred to as the present coating composition I),
as well as
(3) Corrosion-preventing coating composition comprising (A) aqueous coating liquid, (B) zinc powder, (C) aqueous aluminum pigment and (D) extender pigment and / or antirust pigment (hereinafter referred to as the coating composition of the present invention) Also referred to as product II),
Is to provide.
In addition, this invention coating composition I and this invention coating composition II are named generically, and this invention coating composition.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
As a preferred embodiment of the present invention,
(4) The pigment for a corrosion-preventing coating composition according to the above (1), wherein the ratio between the zinc powder and the aqueous aluminum pigment is in the range of 90:10 to 99.8: 0.2 by mass ratio,
(5) The pigment according to (1) or (4), further comprising a rust preventive pigment and / or an extender pigment,
(6) The pigment according to (5), wherein the rust preventive pigment is a phosphate-based pigment,
(7) The pigment according to (5) or (6), wherein the rust preventive pigment is a molybdate-based pigment,
(8) The pigment according to (5), (6) or (7), wherein the extender pigment is talc, zinc oxide, calcium carbonate, mica, barium sulfate,
(9) Zinc dust, water-based aluminum pigment, and the ratio between the rust preventive pigment and / or extender pigment is in the range of 75 to 97 mass%, 0.2 to 8.3 mass%, and 0.1 to 20 mass%, respectively. The pigment according to any one of (5) to (8),
(10) The mass ratio of the nonvolatile content in component (A) to the total amount of component (B) and component (C) is 1: 4 to 1:35, and component (B) and component (C) The corrosion-preventing coating composition according to the above (2), wherein the mass ratio is in the range of 90:10 to 99.8: 0.2 by mass ratio,
(11) The above (2), wherein the aqueous coating liquid of component (A) is at least one selected from a silicon-containing inorganic binder system, a colloidal silica composite system, an acrylic resin system and a polyurethane resin system, (3) or the anticorrosion coating composition according to (10),
(12) The corrosion-preventing coating composition according to the above (11), wherein the colloidal silica composite-based aqueous coating liquid uses a colloidal silica composite emulsion as a binder.
(13) The mass ratio of the nonvolatile content in component (A) to the total amount of component (B), component (C), and component (D) is 1: 4 to 1:35, and component (B), (3), (11) wherein the ratio between the component (C) and the component (D) is in the range of 75 to 97 mass%, 0.2 to 8.3 mass%, and 0.1 to 20 mass%, respectively. Or the anticorrosion coating composition according to (12),
(14) (A ′) containing an aqueous coating liquid containing a colloidal silica composite emulsion as a binder, (B) zinc powder, (C) an aqueous aluminum pigment, and (D) an extender pigment and / or an antirust pigment. A corrosion protection coating composition comprising:
(15) The content of colloidal silica in the nonvolatile content in the component (A ′) is 10 to 80% by mass, and the nonvolatile content in the component (A ′), the components (B), (C) and (D ) The mass ratio of the component to the total amount is 1: 4 to 1:35, and the proportions among the components (B), (C) and (D) are 75 to 97% by mass, 0.2 Corrosion prevention coating composition according to the above (14), which is in the range of ˜8% by mass and 2˜20% by mass,
(16) The composition according to any one of (3) or (11) to (15), wherein the rust preventive pigment is a phosphate-based pigment,
(17) The composition according to any one of (3) or (11) to (16), wherein the rust preventive pigment is a molybdate-based pigment,
(18) The composition according to any one of (3) or (11) to (17), wherein the extender pigment is talc, zinc oxide, calcium carbonate, mica, barium sulfate,
Is mentioned.
[0007]
The pigment of the present invention contains zinc dust and an aqueous aluminum pigment, and may further contain a rust preventive pigment and / or an extender pigment, that is, a rust preventive pigment and / or an extender pigment. It is preferable to contain a pigment.
[0008]
The zinc powder is not particularly limited as long as it is usually used in a corrosion-preventing coating composition, especially a coating composition. Zinc or an alloy mainly composed of zinc, that is, a zinc-based alloy powder or fine flakes is used. However, a powder having an average particle diameter of 2 to 15 μm, particularly 2 to 8 μm, and flakes having an average diameter of 3 to 30 μm and a thickness of 0.5 to 2 μm have good sedimentation properties, and are preferable for coating work.
[0009]
Water-based aluminum pigments are aluminum pigments that have been water-treated to be suitable for water-based anticorrosion coating compositions, especially water-based paint compositions, and are generally treated with a water-based surface treatment of powdered or flaky aluminum pigments. Although the use form is not particularly limited, it may be pasty or dry powder. Examples of the treatment agent used for the aqueous surface treatment include phosphoric acid, phosphoric acid esters such as phosphoric acid monoesters and phosphoric acid diesters or amine adducts thereof, and polymers of higher fatty acids (eg, dimers and trimers). . For making a paste, an organic solvent, preferably mineral spirit, solvent naphtha, toluene, xylene, especially mineral spirit or a mixed solvent thereof with solvent naphtha, toluene or xylene is used.
[0010]
The extender pigment is not particularly limited as long as it is usually used in a corrosion-preventing coating composition, particularly a coating composition, such as silica, talc, clay, kaolin, mica, zinc white, barium sulfate, calcium carbonate, Alumina, zinc oxide, magnesium carbonate, barium carbonate, bentonite and the like can be mentioned, and talc, zinc oxide, calcium carbonate, mica and barium sulfate are preferably used.
[0011]
The anticorrosive pigment is not particularly limited as long as it is usually used in a corrosion-preventing coating composition, especially a coating composition. For example, a chromium-based pigment, a lead-based pigment, a borate-based pigment, a phosphate-based pigment Pigments, molybdate pigments, and the like can be mentioned. Preferably, phosphate pigments and molybdate pigments are used because rust prevention can be further improved.
Examples of the phosphate pigment include zinc phosphate, aluminum phosphate, calcium phosphate, aluminum zinc phosphate, calcium zinc phosphate, phosphorous zinc silicate, zinc-treated aluminum phosphate, and molybdate pigments. Examples thereof include calcium molybdate, aluminum phosphomolybdate, zinc molybdate, zinc calcium molybdate, and zinc phosphomolybdate.
[0012]
About the content rate between each pigment in this invention pigment, it is preferable to set it as the range of 90: 10-99.8: 0.2 by mass ratio with a zinc powder and an aqueous | water-based aluminum pigment.
Furthermore, when it contains a rust preventive pigment and an extender pigment, the ratio between a zinc dust, an aqueous | water-based aluminum pigment, and an antirust pigment and / or an extender pigment is 75-97 mass%, 0.2-8.3 mass, respectively. % And 0.1 to 20% by weight, especially 75 to 97% by weight, 0.3 to 8% by weight and 2 to 20% by weight, in particular 75 to 97% by weight, 0.3 to 5% by weight and 2.7 to 2.7%. A range of 20% by mass is preferable.
By setting it as such a ratio, the performance of this invention coating composition using this invention pigment can be improved so that it may mention later.
[0013]
The coating composition of the present invention comprises the above-mentioned pigment of the present invention and an aqueous coating liquid, that is, (A) an aqueous coating liquid, (B) zinc powder, and (C) an aqueous aluminum pigment and optionally used (D ) It contains an extender pigment and / or a rust preventive pigment, but preferably contains a rust preventive pigment.
[0014]
In the coating composition of the present invention, the aqueous coating liquid of the component (A) is, for example, a silicon-containing inorganic binder system, a colloidal silica composite system, a polyurethane resin system, an acrylic resin system, a polyester resin system, an alkyd resin. Type, epoxy resin type, vinyl resin type, unsaturated polyester resin type, ultraviolet curable resin type, fluorine resin type, melamine resin type, etc., among them silicon-containing inorganic binder type, colloidal silica composite type, polyurethane At least one selected from a resin system and an acrylic resin system is preferable.
[0015]
Examples of the binder used in the aqueous coating liquid of component (A) include silicon-containing inorganic binders, colloidal silica composites, polyurethane resins, acrylic resins, polyester resins, alkyd resins, and epoxy resins. , Vinyl resin-based, unsaturated polyester resin-based, ultraviolet curable resin-based, fluororesin-based or melamine resin-based, among others, colloidal silica composites, especially emulsions thereof, silicon-containing inorganic binders, polyurethane resin-based and acrylic resins. At least one selected from the system is preferred. These include modified products such as silicone-modified acrylic resin binders.
[0016]
Of these binders, the colloidal silica composite is preferably an emulsion.
The colloidal silica composite emulsion is not particularly limited as long as it is usually used in coating compositions, but preferably one or more monomers capable of emulsion polymerization are emulsified in the presence of colloidal silica. What was obtained by polymerizing, and those obtained by blending and dispersing colloidal silica in an aqueous emulsion containing an emulsion polymer of such a monomer, such as homopolymerization type or copolymerization type acrylic emulsion or diene emulsion Etc. One example is an aqueous emulsion in which colloidal silica and a styrene-acrylonitrile copolymer are uniformly dispersed.
[0017]
The silicon-containing inorganic binder is preferably an alkali silicate, in particular ammonium silicate, an alkali metal silicate, or a hydrolysis condensate of a silicate ester, and these are suitable resins such as acrylic resins. In addition, it may be used as an emulsion.
[0018]
The polyurethane resin binder is preferably a one-component type such as a moisture curable type, a blocked isocyanate curable type or a lacquer type, and among them, those containing a carboxyl group or an ester group.
Among these, the carboxyl group-containing polyurethane resin binder may be any one that can be stably dispersed or dissolved in water by neutralization, such as a polyhydric alcohol having a carboxyl group, a polyhydric alcohol, and It can be obtained by reacting a polyvalent isocyanate compound by a conventional method using a chain length adjusting agent as required.
Examples of polyhydric alcohols having a carboxyl group include gluconic acid, dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutyric acid, dihydroxysuccinic acid, and half-esterified products of trihydric alcohols such as glycerin with acid anhydrides such as phthalic anhydride. Polyhydric alcohols include trimethylolpropane, ethylene glycol, propylene glycol, butanediol, hexanediol, trimethylene glycol, diethylene glycol, hexylene glycol, octylene glycol, neopentyl glycol, hydrogenated bisphenol A, polyester polyol, acrylic polyol Polycarbonate polyol, etc., as the polyvalent isocyanate compound, hexamethylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate , Diphenylmethane-4,4'-diisocyanate, trans-cyclohexa-1,4-diisocyanate, m-xylene diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane triisocyanate And free isocyanate group-containing urethane prepolymers as reaction products of such polyisocyanates and polyols, such as polypropylene ether polyols, polyethylene / propylene ether polyols or polyester polyols, and polyisocyanates liquefied by carbodiimidization, etc. Modified polyisocyanates such as ethylenediamine, tolylenediamine, isophoronediamine, Diamine, and the like diamines such as xylene diamine, respectively.
The carboxyl group-containing polyurethane resin-based binder has a molecular weight of 5000 to 2,000,000, particularly 10,000 to 1,000,000, and an acid value of 10 to 50. It is appropriate. If the molecular weight is too small, the water resistance is lowered, and if it is too large, the flexibility is lowered. On the other hand, if the acid value is too small, the stability is lowered, and if it is too large, the water resistance is lowered.
Examples of the carboxyl group- or ester group-containing polyurethane resin-based binder include commercially available products such as UD500 and UD100N manufactured by Mitsui Chemicals, Superflex manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Bondic manufactured by Dainippon Ink and Chemicals, and NS 7X801, 7X813 manufactured by Cee, Neoletz manufactured by ICI Resin, Suncure 825, 822A manufactured by Gunze Sangyo Co., Ltd., and the like are also used.
Examples of the neutralizing agent used when neutralizing the carboxyl group-containing polyurethane resin binder include ammonia, trimethylamine, triethylamine, and triethanolamine.
[0019]
Examples of the acrylic resin binder include homopolymers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl acrylate, or glycidyl methacrylate. Examples include (meth) acrylic acid resins such as polymers, and modified acrylic resin materials such as silicone-modified acrylic resins.
The acrylic resin binder has a molecular weight of 5,000 to 1,000,000, especially 10,000 to 1,000,000, and a hydroxyl value of 5 to 300, especially 10 to 200. Is appropriate.
Commercially available products such as Kanebinol KD7 and KD11 manufactured by NSC Japan, and Polydurex G613 and G620 manufactured by Asahi Kasei Kogyo Co., Ltd. are also used as the silicone-modified acrylic resin binder.
[0020]
In the coating composition of the present invention, the mass ratio between the nonvolatile content in the component (A) and the total amount of the component (B) and the component (C), or the component (B), the component (C), and the component (D) is It is preferably 1: 4 to 1:35.
Furthermore, in the coating composition I of the present invention, the ratio of the component (B) and the component (C) is in the range of 90:10 to 99.8: 0.2 by mass ratio, and in the coating composition II of the present invention. , (B) component, (C) component, and (D) component ratio is 75-97 mass%, 0.2-8.3 mass%, and 0.1-20 mass%, respectively, among them, 75-97 mass %, 0.3 to 8% by mass and 2 to 20% by mass, particularly 75 to 97% by mass, 0.3 to 5% by mass and 2.7 to 20% by mass are preferable.
[0021]
In the coating composition of the present invention, the non-volatile content in the component (A) is the total amount of pigment components such as the component (B) and the component (C), or the component (B), the component (C) and the component (D). On the other hand, if it is too lower than the above range, various physical properties of the coating will be reduced, and if it is too high, the corrosion resistance and rust resistance will be reduced.
When the ratio of these components to the total amount of the components (B) and (C) or (B), (C) and (D) is lower than the above range, the anticorrosive property If the content is higher than the above range, white rust is generated and the durability of the coating film is reduced. If the proportion of the component (C) is lower than the above range, the rust resistance is reduced. Further, if it is higher than the above range, the adhesiveness is lowered and the coating film becomes brittle, and if the proportion of the component (D) used in some cases is lower than the above range, the white rust suppressing effect is reduced, and the above range. If it is higher, various physical properties of the coating film tend to be lowered.
[0022]
As the coating composition of the present invention, preferably, the aqueous coating liquid of the component (A) is basically a colloidal silica composite emulsion as a binder diluted and dispersed with an appropriate amount of water, Corrosion prevention comprising (A ') a water-based coating liquid containing a colloidal silica composite emulsion as a binder, (B) zinc powder, (C) a water-based aluminum pigment, and (D) an extender pigment and / or a rust preventive pigment. A coating composition is used, and the corrosion protection coating composition is an aqueous coating composition.
In this water-based coating composition, as a suitable component (A ′), the content of colloidal silica in the nonvolatile content is 10 to 80% by mass, preferably 25 to 65% by mass, more preferably the nonvolatile content therein. May be those in the range of 30-55% by weight. If this ratio is less than 10% by mass, the water resistance tends to decrease and blisters are likely to occur, and if it exceeds 80% by mass, various physical properties of the coating film (for example, flexibility, hardness, adhesion, etc.) tend to decrease. This is not preferable.
[0023]
Moreover, about the suitable mixture ratio of the composition component of a water-based coating composition, the mass ratio of the non volatile matter amount in (A ') component and the total amount of (B) component, (C) component, and (D) component is 1: The ratio is in the range of 4 to 1:35, preferably 1: 7 to 1:30, more preferably 1: 9 to 1:25, and the ratio among the components (B), (C) and (D) That is, the percentage of each of these components to the total amount of these three components is 75 to 97% by mass, 0.2 to 8% by mass and 2 to 20% by mass, preferably 75 to 97% by mass and 0.3 to 5% by mass, respectively. And 2.7 to 20% by mass, more preferably 80 to 96% by mass, 0.5 to 5% by mass and 3.5 to 15% by mass, still more preferably 85 to 95% by mass, and 1.0 to 5% by mass. And it is the range of 4.0-10 mass%.
When the nonvolatile content in the component (A ′) is too lower than the above range with respect to the total amount of the component (B), the component (C) and the component (D), various physical properties of the coating film are deteriorated, and when it is too high. Corrosion resistance and rust resistance are reduced.
In the percentage ratio of these components to the total amount of the component (B), the component (C) and the component (D), if the proportion of the component (B) is lower than the above range, the anticorrosion and rust preventive properties are reduced. If it is higher, the occurrence of white rust will increase and the durability of the coating will decrease, and if the proportion of component (C) is lower than the above range, rust prevention will decrease, and if it is higher than the above range, adhesion will decrease. When the ratio of the component (D) is lower than the above range, the white rust inhibiting effect is reduced, and when it is higher than the above range, various physical properties of the coating film tend to be reduced. .
[0024]
The coating composition of the present invention includes the above-described coating composition, which is a preferred embodiment thereof, as long as it does not defeat the purpose of the present invention. Stopping agent, film-forming aid, wetting agent, antifoaming agent, antifreezing agent, leveling agent, dispersing agent, anti-settling agent, plasticizer, flameproofing agent, antifungal agent, UV absorber, antioxidant, coating surface A regulator, a surfactant, a stabilizer and the like can be blended.
Examples of coloring pigments include petals, titanium white, carbon black, aniline black, gunjo, cadmium yellow, chrome yellow, lead white, watching red, organic blue such as cyanine blue, and organic green such as phthalocyanine green. .
Examples of the anti-settling agent include organic bentonite, polyethylene oxide, and aerosil.
[0025]
The coating composition of the present invention includes the above-mentioned coating composition which is a preferred embodiment thereof, and includes a three-can set in which a coating liquid, zinc dust or a mixture of the powder and a predetermined pigment, and an aqueous aluminum pigment paste are separately provided, and a coating liquid. And a mixture of zinc dust and aqueous aluminum pigment (solid powder), or a mixture of zinc dust, aqueous aluminum pigment and a predetermined pigment, are provided in the form of two cans. In the case of the form, each can component of the above set may be sufficiently mixed and stirred with a stirrer or the like when the coating is applied to the predetermined steel material, and then used. The coating on the steel material may be performed by a normal coating method such as spraying, dipping, brush coating, mechanical coating by an appropriate coater such as a roll coater, and drying after coating may be performed by natural drying or hot air drying. .
[0026]
The coating composition of the present invention includes the above-described coating composition which is a preferred embodiment thereof, and particularly when applied to a steel material made of galvanized steel and / or zinc alloy-plated steel. Excellent corrosion resistance and rust resistance against exposed parts of the base steel and damaged parts of the plating layer. Preferred examples of the zinc alloy plated steel include zinc-aluminum alloy plated steel, zinc-aluminum-magnesium alloy plated steel, and zinc-aluminum-magnesium-silicon alloy plated steel.
Moreover, this invention coating composition exhibits a big effect, when the said coating composition which is the suitable aspect is applied to the steel materials which consist of zinc alloy plating steel which contains aluminum in a plating part. Although this phenomenon has not been fully elucidated, since this steel material contains aluminum in the plated portion, the plated portion and a coated portion such as a painted portion containing a water-based aluminum pigment by the coating composition of the present invention are used. It is presumed that the contact potential difference is reduced.
Furthermore, the coating composition of the present invention includes the coating composition according to the preferred embodiment, and when applied to a steel material made of zinc alloy plated steel containing magnesium together with aluminum in the plated portion, a more excellent effect is obtained. It is possible to prevent the occurrence of red rust from the painted part over a long period of time. The reason for this is not clear enough, but in this steel material, the magnesium contained in the plated part reduces the contact potential difference between the plated part and the painted part, or the magnesium in the plated part ionizes at the initial stage of corrosion. It is presumed that corrosion of the painted part is remarkably suppressed by flowing into the painted part as a water-soluble salt.
[0027]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
[0028]
The antirust performance of the coating film obtained using the coating composition of each example was evaluated as follows.
Rust prevention:
A combined cycle corrosion test (CCT) defined in JASO M 609-91 was conducted to examine the presence or absence and degree of red rust occurrence for each predetermined cycle, and evaluated according to the following criteria.
○: Red rust occurrence rate is less than 1%
Δ: Red rust occurrence rate of 1% or more and less than 10%
X: Red rust incidence 10% or more and less than 50%
XX: Red rust occurrence rate 50% or more
In one cycle of the corrosion test, a sample was sprayed with 5% salt water at a temperature of 35 ° C. for 2 hours, dried at a temperature of 60 ° C. and a humidity of 30% for 4 hours, and then at a temperature of 50 ° C. and a humidity of 95%. It consists of a wet treatment for 2 hours.
[0029]
Example 1
First, the coating liquid A was prepared as follows.
That is, a binder composed of 10 parts by mass of QAS25 (trade name, manufactured by Nissan Chemical Co., colloidal silica) and 40 parts by mass of Movinyl 8010 (trade name, manufactured by Clariant Polymer Co., Ltd., colloidal silica composite emulsion), Solfit [trade name , Manufactured by Kuraray Co., Ltd., 3-methyl-3-methoxybutanol (film forming aid)] 4.9 parts by mass, Benton EW (trade name, manufactured by RHEOX, hectorite-based thickener) 1.0 part by mass, dehydrane 1620 (trade name, manufactured by San Nopco, silicone-based antifoaming agent) 0.2 parts by mass and 41.4 parts by mass of ion-exchanged water are mixed, and the pH is adjusted to 10 with a suitable pH adjuster, and the coating liquid. A was prepared.
Next, LS-2 (trade name, manufactured by Mitsui Kinzoku Paint Chemical Co., Ltd., zinc powder) 95.0 parts by mass and Micron A (trade name, manufactured by Hayashi Kasei Co., Ltd., talc) are added to 28.2 parts by weight of this coating liquid A. 0 parts by mass and 2.0 parts by mass of AW520B (trade name, manufactured by Asahi Kasei Co., Ltd., aluminum paste) were added, and the mixture was sufficiently mixed and stirred with a stirrer to prepare a uniform aqueous coating composition.
[0030]
Examples 2-11, Comparative Examples 1-6
An aqueous coating composition was prepared in the same manner as in Example 1, using the coating liquid A prepared in the same manner as in Example 1, with the composition components and composition ratios shown in Table 1 below.
In addition, about the thing except the thing shown in Example 1 among the composition components in a table | surface, the following commercial items were used.
Ca phosphate, that is, calcium phosphate: manufactured by Kikuchi Color Co., Ltd., CP-Z
Ca molybdate, that is, calcium molybdate: manufactured by Kikuchi Color Co., Ltd., LF Bousei MC-400WR
Zinc phosphate: Mitsui Kinzoku Co., Ltd., zinc phosphate S
Phosphomolybdate Al, that is, aluminum phosphomolybdate: manufactured by Kikuchi Color Co., Ltd., LF bowsey PM-303W
Al phosphate, that is, aluminum phosphate compound: Teika Co., Ltd., K-WHITE 140W
[0031]
On the other hand, the test original plate was prepared as follows.
That is, a Zn-5% Al plated steel sheet having dimensions of 70 mm × 150 mm (plating adhesion amount per side: 183 g / m ² , Plate thickness: 3.2 mm) are prepared, and these are 20 liters using YGW-12 (trade name, manufactured by Daido Steel Co., Ltd., DS1A) on the short side and carbon dioxide as a shielding gas. The butt welding process was performed while flowing at a flow rate of / min. The processing conditions at that time were a current of 150 to 160 A, a voltage of 22 V, and a welding processing speed of 50 cm / min.
[0032]
After cleaning the weld bead part of this original plate using a wire brush, the weld bead part is covered, and each aqueous coating composition of each of the above Examples and Comparative Examples has a dry film thickness of 40 ± 5 μm over a total length of 80 mm. It was painted with a brush and dried in a room at 20 ° C. and 65% humidity for 7 days to obtain a coating film. The results of evaluating the performance of the obtained coating film are shown in Table 1.
[0033]
[Table 1]

[0034]
From this, while the coating film using the coating composition of each comparative example generates rust in the test of 100 cycles, all the coating films using the coating composition of each of the above examples of the present invention are used. It is clear that rust does not occur in the 100-cycle test, and particularly when a rust preventive pigment is used, rust does not occur even in the 150-cycle test and is excellent in rust resistance.
[0035]
Examples 12-14
An aqueous coating composition having the same composition and proportion as in Example 6 was prepared, and a Zn-5% Al-0.1% Mg-plated steel sheet (plating adhesion amount per side: 161 g / m). ² , Plate thickness: 3.2 mm), Zn-6% Al-3% Mg plated steel sheet (plating adhesion amount per side: 154 g / m ² , Plate thickness: 3.2 mm) and Zn-11% Al-3% Mg-0.15% Si-plated steel plate (plating adhesion amount per side: 158 g / m ² , Plate thickness: 3.2 mm) were coated on the weld bead portions and used for the test. In addition, the welding conditions of these test original plates, coating conditions, and evaluation of the rust prevention performance of the coating film were performed under the same conditions and methods as in Example 1. Table 2 shows the results of evaluating the performance of the obtained coating film.
[0036]
[Table 2]

[0037]
As apparent from Table 2, when the coating composition prepared in the same manner as in Example 6 was applied to zinc-aluminum-based plated steel or zinc-aluminum-silicon-based plated steel containing magnesium, the zinc of Example 6- Compared with the case of coating on aluminum-based plated steel, red rust does not occur for a longer period of time, and extremely excellent rust prevention is obtained.
[0038]
Example 15
First, the coating liquid B was prepared as follows.
That is, 56.6 parts by mass of a binder composed of olestar UD500 (trade name, manufactured by Mitsui Chemicals, water-based urethane resin, NV 38%), and 4.0 parts by mass of a film forming aid composed of N-methyl-2-pyrrolidone. , Benton EW (trade name, manufactured by RHEOX, hectorite-based thickener) 1.0 part by mass, Dehydran 1620 (trade name, manufactured by San Nopco, silicone-based antifoaming agent) 0.2 part by mass, and ion-exchanged water 35 .7 parts by mass was mixed, and a coating liquid B was prepared by adjusting the pH to 10 with an appropriate pH adjuster.
Next, 28.2 parts by mass of this coating liquid was mixed with 98.0 parts by mass of LS-2 (trade name, manufactured by Mitsui Kinzoku Paint Chemical Co., Ltd., zinc powder) and AW520B (trade name, manufactured by Asahi Kasei Co., Ltd., aluminum paste) 2.0. A uniform water-based coating composition was prepared by adding part by mass and sufficiently mixing and stirring with a stirrer.
[0039]
Example 16
An aqueous coating composition was prepared in the same manner as in Example 15 except that the coating liquid C prepared as follows was used instead of the coating liquid B.
The coating liquid C is 47.8 parts by weight of a binder composed of Kanebinol KD11 (trade name, manufactured by Nippon SC, acrylic / silicone emulsion, NV 45%), Solfit [trade name, 3-methyl, manufactured by Kuraray Co., Ltd. -3-Methoxybutanol (film forming aid)] 4.9 parts by mass, Benton EW (trade name, manufactured by RHEOX, hectorite-based thickener) 1.0 part by mass, Dehydrane 1620 (trade name, manufactured by San Nopco) , Silicone-based antifoaming agent) 0.2 parts by mass and 43.6 parts by mass of ion-exchanged water were mixed, and the mixture was further adjusted to have a pH of 10 with an appropriate pH adjuster.
[0040]
Examples 17 to 26, Comparative Examples 7 to 11
Using any one of the coating liquids A to C prepared in the same manner as in Example 1, Example 15 or Example 16, the composition components and composition ratios shown in Table 3 below are used, and the aqueous composition is the same as in Example 15. A coating composition was prepared.
The composition components in the table are the same as those described above.
[0041]
Results of evaluating the performance of the coating film on the test original plate obtained in the same manner as in Example 1 using each of the aqueous coating compositions of these Examples and Comparative Examples in the same manner as in Example 1 described above. Is shown in Table 3.
[0042]
[Table 3]

[0043]
From Table 3, the coating film using the coating compositions of Comparative Examples 7 to 9 using only zinc dust as a pigment generates rust in a 30-cycle test, whereas aqueous zinc is used as a pigment together with zinc dust. In any of the coating films using the coating compositions of Examples 15 to 23, rust does not occur in the 60-cycle test, and rust does not spread significantly even in the 150-cycle test. Furthermore, it is clear that the coating films using the coating compositions of Examples 24 to 26 to which rust preventive pigments are added do not generate rust even in a 150 cycle test and are excellent in rust preventive properties.
[0044]
Examples 27-29
An aqueous coating composition having the same composition and composition ratio as in Example 20 was prepared, and a Zn-5% Al-0.1% Mg-plated steel sheet (plating adhesion amount per side: 161 g / m). ² , Plate thickness: 3.2 mm), Zn-6% Al-3% Mg plated steel sheet (plating adhesion amount per side: 154 g / m ² , Plate thickness: 3.2 mm) and Zn-11% Al-3% Mg-0.15% Si-plated steel plate (plating adhesion amount per side: 158 g / m ² , Plate thickness: 3.2 mm) were coated on the weld bead portions and used for the test. In addition, the welding conditions of these test original plates, coating conditions, and evaluation of the rust prevention performance of the coating film were performed under the same conditions and methods as in Example 1. Table 4 shows the results of evaluating the performance of the obtained coating film.
[0045]
[Table 4]

[0046]
As is clear from Table 4, zinc-aluminum-based steel or zinc-aluminum-silicon-based steel containing magnesium is used in Example 20 as the steel material to which the coating composition of the example is applied. The former is preferred because it does not generate red rust over a longer period of time than the zinc-aluminum-based plated steel and exhibits excellent rust prevention properties.
[0047]
【The invention's effect】
The pigment of the present invention can be imparted with excellent properties as shown in the composition by blending with the anticorrosion coating composition.
The corrosion-preventing coating composition of the present invention is excellent in rust prevention, and can be made to have a slow consumption of zinc powder, which is particularly effective for rust prevention, and the generation of white rust caused by zinc powder in the coating film. It is possible to suppress long-term rust prevention, and is particularly suitable for galvanized steel and zinc alloy plated steel.
In addition, the corrosion-preventing coating composition of the present invention is excellent in terms of pollution prevention and environmental conservation because it uses water as a solvent or is water-rich with as few organic solvents as possible.
Therefore, the corrosion-preventing coating composition of the present invention is a steel structure or steel structure, particularly made of galvanized steel or galvanized steel, such as roads, bridges, railways, harbors, buildings, factories, prefabricated houses, power plants, steel towers. It is suitable for applications requiring heavy anticorrosion such as amusement parks, swimming pools, and other entertainment / amusement facilities.

Claims

A pigment for a corrosion-preventing coating composition comprising zinc dust and an aqueous aluminum pigment.

The pigment for a corrosion-preventing coating composition according to claim 1, wherein the ratio of the zinc powder to the aqueous aluminum pigment is in the range of 90:10 to 99.8: 0.2 by mass ratio.

The pigment according to claim 1 or 2, further comprising a rust preventive pigment and / or an extender pigment.

The pigment according to claim 3, wherein the rust preventive pigment is a phosphate-based pigment.

The pigment according to claim 3 or 4, wherein the rust preventive pigment is of molybdate type.

6. The pigment according to claim 3, 4 or 5, wherein the extender pigment is talc, zinc oxide, calcium carbonate, mica, or barium sulfate.

The ratio between zinc dust, aqueous aluminum pigment, and antirust pigment and / or extender pigment is in the range of 75 to 97 mass%, 0.2 to 8.3 mass%, and 0.1 to 20 mass%, respectively. Item 7. The pigment according to any one of Items 3 to 6.

A corrosion prevention coating composition comprising (A) an aqueous coating liquid, (B) zinc dust and (C) an aqueous aluminum pigment.

The mass ratio of the nonvolatile content in the component (A) and the total amount of the component (B) and the component (C) is 1: 4 to 1:35, and the ratio of the component (B) to the component (C) is The corrosion-preventing coating composition according to claim 8, which has a mass ratio of 90:10 to 99.8: 0.2.

A corrosion prevention coating composition comprising (A) an aqueous coating liquid, (B) zinc powder, (C) an aqueous aluminum pigment, and (D) an extender pigment and / or a rust preventive pigment.

11. The aqueous coating liquid of component (A) is at least one selected from a silicon-containing inorganic binder system, a colloidal silica composite system, an acrylic resin system, and a polyurethane resin system. Corrosion prevention coating composition.

The corrosion-preventing coating composition according to claim 11, wherein the colloidal silica composite-based aqueous coating liquid contains a colloidal silica composite emulsion as a binder.

The mass ratio of the nonvolatile content in component (A) to the total amount of component (B), component (C) and component (D) is 1: 4 to 1:35, and component (B), (C) 13. The corrosion prevention according to claim 10, 11 or 12, wherein the ratio between the component and the component (D) is in the range of 75 to 97% by mass, 0.2 to 8.3% by mass and 0.1 to 20% by mass, respectively. Coating composition.

Corrosion prevention comprising (A ') a water-based coating liquid containing a colloidal silica composite emulsion as a binder, (B) zinc powder, (C) a water-based aluminum pigment, and (D) an extender pigment and / or a rust preventive pigment. Coating composition.

The content of colloidal silica in the nonvolatile content in the component (A ′) is 10 to 80% by mass, and the nonvolatile content in the component (A ′) and the components (B), (C) and (D) The mass ratio with respect to the total amount is 1: 4 to 1:35, and the proportions among the components (B), (C) and (D) are 75 to 97% by mass and 0.2 to 8% by mass, respectively. The corrosion protection coating composition according to claim 14, which is in the range of 1% and 2 to 20% by mass.

The composition according to any one of claims 10 to 15, wherein the rust preventive pigment is a phosphate-based pigment.

The composition according to any one of claims 10 to 16, wherein the rust preventive pigment is of molybdate type.

The composition according to any one of claims 10 to 17, wherein the extender pigment is talc, zinc oxide, calcium carbonate, mica, or barium sulfate.