JP2004197151A - Corrosion-resistant iron manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing corrosion-resistant iron having high rust-preventiveness and durability without using or containing harmful chromium compound. <P>SOLUTION: The corrosion-resistant iron is manufactured by applying a rust-preventive cover composition with a single compound (a) having at least one phenolic hydroxy group in the molecule and silane compound expressed by general formula (1), or with at least two kinds of mixtures or condensation products of two kinds of mixtures, or mixtures thereof to a surface of the iron covered by an under-coat agent mainly consisting of at least one kind of zinc and aluminum as essential ingredient, and hardening the applied stuff by the treatment at room temperature or heating treatment. In addition, a top coat composition with silicates expressed by general formula (2), silicates expressed by general formula (3), mixtures thereof or condensation products thereof is applied to the corrosion-resistant iron to form a protective layer hardened by the treatment at room temperature or heating treatment. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００７】
式中Ｒ¹はグリシドキシ基または炭素数５もしくは６のエポキシシクロアルキル基を有する１価の基；Ｒ²は１価の炭素数１〜６の低級アルキル基；Ｘは炭素数１〜６のアルコキシ基；及びａは０，１または２を表す。
【０００８】
（ハ）一般式（２）で示されるシリケート類、及び一般式（３）で示されるケイ酸塩類群から選ばれる少なくとも１種以上のシロキサン結合を有する化合物及び／またはそれらの縮合物。
【０００９】
【化６】

【００１０】
式中Ｒ³は水素原子及び１価の炭素数１〜６の低級炭化水素基の群から選ばれた基である（但しＲ³が複数個の場合は同一または異なっていても良い）；およびｂは１以上の整数である。
【００１１】
【化７】

【００１２】
式中Ｍはアルカリ金属およびアンモニウム類の群からから選ばれた基である（但しＭが複数個の場合は同一または異なっていても良い）；およびｎは１以上の整数である。
【００１３】
さらに、上述の本発明の目的は、前述の上塗り被覆組成物を前記式（２）で示されるシリケート類及び下記式（４）で示されるシラン化合物のそれぞれ１種もしくは２種以上の共縮合物を必須成分とする被覆組成物とし、本組成物を塗付し室温処理または加熱処理により硬化することにより達成される。
【００１４】
【化８】

【００１５】
式中Ｒ⁴は、グリシドキシ基、炭素数５もしくは６のエポキシシクロアルキル基、（メタ）アクリル基、アミノ基、メルカプト基、アリール基、及びシクロアルキル基から選ばれる１以上の官能基を有する炭素数１〜１８の１価の基；炭素数１〜１８のアルキル基；炭素数２〜１８のアルケニル基；又は炭素数１〜１８のハロゲン置換アルキル基であり、Ｒ⁵は炭素数１〜６の低級アルキル基であり、Ｙは炭素数１〜６のアルコキシ基；炭素数１〜６のケトキシム基；又は炭素数１〜６のアセトキシ基であり、ｃは０、１または２の整数を表す。
【００１６】
【発明の実施の形態】
以下本発明を詳細に説明する。
本発明における下塗り層は鉄よりもイオン化傾向の大きな亜鉛、アルミから選ばれた少なくとも１種を主成分とする金属による皮膜であり、犠牲陽極となり鉄材の酸化を妨げるものである。これら金属による下塗層は溶融鍍金、電気鍍金、浸透鍍金、化学鍍金及び溶射さらにはこれら金属の微粉を含む塗料の塗布等の方法によって形成することができる。
本発明に使用される防錆被覆組成物における成分（イ）の同一分子中に少なくとも１つのフェノール性水酸基を有する化合物としては、フェノール、クレゾール、チモール、ブロモフェノール、ナフトール、アニリノフェノール等に代表される１価フェノール類、ピロカテキン（カテコール）、レゾルシン、ヒドロキノン、オルシン、ウルシオール、ビスフェノールＡ、ビナフトール等に代表される２価フェノール類、ピロガロール、フロログルシン、ヒドロキシヒドロキノン、トリヒドロキシ安息香酸等に代表される３価フェノール類、タンニン酸、フェノール−ホルムアルデヒド縮合物等の多価フェノール類が例示されるがこれらに限定されるものではない。これら同一分子中に少なくとも１つのフェノール性水酸基を有する化合物は、単独でも、または、２種以上を混合しても使用することができる。これらフェノール類は、鉄と反応して鉄塩となり錯化合物を生成し、酸素の透過を低減するため、下塗り剤の酸化を抑止することができる。その結果、下塗り層の犠牲陽極としての性能劣化が抑制されるために鉄材の高耐食性が得られるものと考えられる。しかしながらこれらフェノール類は水溶性が高いため、単独で中塗り層として使用すると、たとえば上塗り層が傷を受けた場合等においては、浸水等による溶出が起こり防食耐久性が不十分となる。
【００１７】
一般式（２）で示されるシラン化合物（ロ）は上記フェノール類の溶出を防止し、耐久性のある防食塗膜を形成するために使用されるものである。シラン化合物（ロ）は上記フェノール類と縮合し、高分子量化するため、上記フェノール類の溶出が防止されるとともに、シラン化合物の分子内に含まれるエポキシ基により、金属を含有する下塗り層への密着性が向上するため、これらの相乗効果により防食耐久性が向上するものと考えられる。
一般式（２）で示されるシラン化合物として
（３−グリシドキシプロピル）ジメチルエトキシシラン
（３−グリシドキシプロピル）メチルジエトキシシラン
（３−グリシドキシプロピル）ジメチルメトキシシラン
（３−グリシドキシプロピル）メチルジメトキシシラン
（３−グリシドキシプロピル）トリメトキシシラン
５，６−エポキシヘキシルトリエトキシシラン
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
２−（３，４−エポキシシクロヘキシル）エチルトリエトキシシラン
が例示されるがこれらに限定されるものではない。
【００１８】
本発明の上塗り被覆組成物として使用される成分（ハ）は乾燥によりシラノール基が脱水縮合し、３次元架橋により強固な塗膜を形成し防錆塗膜を保護するものである。式（２）で示されるシリケート類は通常ケイ素のアルコキシドの脱水縮合により得られるオリゴマーである。アルコキシドの構造、分子量については特に制限されないが、テトラメトキシシランの脱水縮合により得られるメチルシリケート及びテトラエトキシシランの脱水縮合により得られるエチルシリケートは入手が容易でかつ反応性が高く好適である。また、式（３）で示されるケイ酸塩類としては、ケイ酸リチウム、ケイ酸ナトリウム、ケイ酸カリウム等のアルカリ金属塩、メチルトリプロパノールアンモニウムシリケート、ジメチルジプロパノールアンモニウムシリケート等のケイ酸アミン等が例示される。
【００１９】
これら式（２）及び式（３）で示されるシロキサン結合を有する化合物は単独でも、または、２種以上を混合しても使用することができる。さらに、これら式（２）及び式（３）で示されるシロキサン結合を有する化合物は単独、または、２種以上を混合し、さらに縮合反応を行い、高分子量体及びまたは共縮合体として使用することもできる。
【００２０】
また、本発明で得られる耐食性鉄材がたとえば高温塩水中、酸性塩水中やアルカリ性塩水中などの過酷な環境下で使用される場合式（２）及び（３）で示されるシロキサン結合を有する化合物を縮合してなる保護層の耐久性をさらに高めることを目的とし、式（２）及び（３）で示されるシロキサン結合を有する化合物と式（４）で示されるシラン化合物との共縮合体を使用することができる。式（２）及び（３）で示されるシロキサン結合を有する化合物と式（４）で示されるシラン化合物との共縮合体は式（２）及び（３）で示されるシロキサン結合を有する化合物と式（４）で示される化合物を予め縮合したものを塗布し室温処理または加熱処理により硬化させることにより得ることができるが、式（２）及び（３）で示されると式（４）で示される化合物の混合物を塗布し、室温処理または加熱処理により硬化させることによっても得ることが出来る。
一般式（４）で示されるシラン化合物としては
トリメチルクロロシラン
トリメチルメトキシシラン
メチルトリス（メチルエチルケトキシム）シラン
ジメチルジアセトキシシラン
ドデシルトリエトキシシラン
ドデシルメチルジクロロシラン
３−クロロプロピルトリクロロシラン
３−クロロプロピルトリメトキシシラン
３−クロロプロピルジメチルクロロシラン
３−クロロプロピルジメチルメトキシシラン
クロロメチルジメチルクロロシラン
クロロメチルジメチルイソプロポキシシラン
１１−ブロモウンデシルジメチルクロロシラン
ビニルトリス（メチルエチルケトキシム）シラン
ビニルメチルジメトキシシラン
ビニルジフェニルエトキシシラン
アリルジメチルメトキシシラン
アリルジメチルクロロシラン
３−（Ｎ−アリルアミノ）プロピルトリメトキシシラン
（３−グリシドキシプロピル）ジメチルエトキシシラン
（３−グリシドキシプロピル）メチルジエトキシシラン
（３−グリシドキシプロピル）ジメチルメトキシシラン
（３−グリシドキシプロピル）メチルジメトキシシラン
（３−グリシドキシプロピル）トリメトキシシラン
５，６−エポキシヘキシルトリエトキシシラン
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
２−（３，４−エポキシシクロヘキシル）エチルトリエトキシシラン
（３−アクリロキシプロピル）ジメチルクロロシラン
（３−アクリロキシプロピル）メチルジメトキシシラン
（３−メタクリロキシプロピル）メチルジクロロシラン
（３−メタクリロキシプロピル）メチルジメトキシシラン
Ｎ−（２−アミノエチル）−３−アミノプロピルジメチルメトキシシラン
Ｎ−（６−アミノヘキシル）アミノプロピルメチルジメトキシシラン
メルカプトメチルジメチルメトキシシラン
３−メルカプトプロピルメチルジエトキシシラン
フェニルエチルジクロロシラン
フェニルジメチルクロロシラン
フェネチルジメチルメトキシシラン
３−フェノキシプロピルトリクロロシラン
シクロヘキシルメチルジメトキシシラン
シクロオクチルジメチルクロロシラン
［２−（３−シクロヘキセニル）エチル］ジメチルメトキシシラン
が例示されるがこれらに限定されるものではない。
【００２１】
本発明の耐食性鉄材の中塗りに使用される防錆被覆組成物における成分（イ）、成分（ロ）の配合比は要求される防錆性能によって決定すれば良く、特に限定されるものではないが、本発明組成物の塗工性、硬化皮膜強度の点から、好ましくは成分（イ）と成分（ロ）の重量混合比（イ）：（ロ）が２０：８０から８０：２０さらに好ましくは４０：６０〜６０：４０の範囲である。
【００２２】
上記中塗り剤として用いられる防錆被覆組成物は、スプレー、ディッピング、刷毛塗、印刷等により表面が亜鉛、アルミから選ばれた少なくとも１種を主成分とする下塗り剤により被覆された鉄材へ塗布することができる。塗布量は、通常乾燥膜厚で５〜２００μｍであるがこれに限定されない。
【００２３】
また、上記防錆被覆組成物は塗布した後、例えば室温で２〜１０時間、あるいは１５０℃で３０分〜１時間加熱することにより硬化塗膜を得ることができる。さらに上塗り被覆組成物についても、同様にして前記防錆被覆組成物が被覆された鉄材表面に塗付し、硬化させ保護層を形成することができる。
【００２４】
さらに、本発明の防錆被覆組成物には、本発明組成物の特性を損なわない範囲において他の添加剤を適量配合して良い。他の添加剤としては、硬化を早くする目的で添加される、金属アルコキシド等の硬化触媒、粘度を調整する目的で添加される水、アルコール類、ケトン類、グリコール類等の希釈溶剤、ガラス、石英、水酸化アルミニウム、アルミナ、カオリン、タルク、炭酸カルシウム、珪酸カルシウム、水酸化マグネシウム等の無機充填剤、アクリル樹脂粉、エポキシ樹脂粉、ポリエステル樹脂粉等の有機充填剤、カーボンブラック、ベンガラ、フタロシアニンブルー、クロ−ムイエロー、二酸化チタン等の顔料または染料に代表される着色剤、金属粉、滑剤、離型剤、界面活性剤、カップリング剤等が例示されるが、これらに限定されるものではない。
【００２５】
さらに本発明により製造された耐食性鉄材は、その表面を保護、加飾、着色する目的で各種塗料、コーティング剤を塗布することができる。
【００２６】
【実施例】
以下、実施例をあげて本発明の代表的な例を更に詳細に説明するが、本発明はこれらの実施例によって限定されるものではない。
なお、例中「部」とあるのは「重量部」を表す。
［実施例１〜３、比較例１〜２：防錆被覆組成物の調製］
それぞれの防錆被覆組成物は表１の原料成分処方に従って製造した。
【００２７】
【表１】

【００２８】
表１に示すそれぞれの原料成分を三角フラスコに入れ、室温で３０分撹拌混合し、さらに６０℃で２時撹拌混合後室温まで放冷し、目開き５０μｍのナイロンメッシュでろ過することにより所期の防錆被覆組成物を得た。なお、表中の原料成分（Ａ）〜（Ｇ）は下記に示す通りである。
（Ａ）３，４，５−トリヒドロキシ安息香酸エチルエステル（関東化学株式会社）
（Ｂ）１，２−ベンゼンジオール（関東化学株式会社）
（Ｃ）３−グリシドキシプロピルトリメトキシシラン（Ｓ５１０チッソ株式会社）
（Ｄ）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（Ｓ５３０チッソ株式会社）
（Ｅ）３−メタクリロキシプロピルトリメトキシシラン（Ｓ７１０ チッソ株式会社）
（Ｆ）９９．５％エタノール（関東化学株式会社）
（Ｇ）精製水（関東化学株式会社）
［実施例４〜９、比較例３〜４：上塗り被覆組成物の調製］
それぞれの上塗り被覆組成物を表１の原料成分処方に従って製造した。
【００２９】
【表２】

【００３０】
表２に示すそれぞれの原料成分を三角フラスコに入れ、室温で３０分撹拌混合し、さらに６０℃で２時撹拌混合後室温まで放冷し、目開き５０μｍのナイロンメッシュでろ過することにより所期の被覆組成物を得た。なお、表中の原料成分（Ｈ）〜（Ｓ）は下記に示す通りである。
（Ｈ）メチルシリケート（ＭＳ−５１三菱化学株式会社）
（Ｉ）アンモニウムシリケート（アミンシリケートキャス２５日産化学工業株式会社）
（Ｊ）トリメチルメトキシシラン（ＡＹ４３−０４３東レ・ダウコーニング・シリコーン株式会社）
（Ｋ）Ｎ−（２−アミノエチル）３−アミノプロピルメチルジメトキシシラン（Ｓ３１０チッソ株式会社）
（Ｌ）３−グリシドキシプロピルメチルジメトキシシラン（Ｓ５２０チッソ株式会社）
（Ｍ）メチルトリス（メチルエチルケトキシム）シラン（ＭＴＯ東レ株式会社）
（Ｎ）９９．５％エタノール（関東化学株式会社）
（Ｏ）精製水（関東化学株式会社）
（試験片の調製）
上記のように調製した防錆被覆組成物と上塗り被覆組成物とを用いて、下記のように試験片を調製した。
【００３１】
２５×１００×２ｍｍの鋼鈑表面をショットブラスト法により洗浄後、溶射法により付着量が２０ｇ／ｍ²となるように亜鉛を塗布した。この亜鉛処理された鋼鈑を表１に示す組成物に１０分間浸漬後引き上げ、室温で３０分乾燥後さらに１５０℃のオーブンで１時間乾燥させ室温まで放冷し、さらに表２に示す組成物に１０分間浸漬後引き上げ、室温で３０分乾燥後、さらに１５０℃のオーブンで１時間乾燥させ試験片とした。
（塩水噴霧試験）
上記のように調製した試験片の片面に５％食塩水を連続噴霧し、鋼鈑表面の赤錆の発生を観察した。結果を表３に示す。尚、表中の塩水噴霧試験（時間）は、試験数を各３とし、目視により内２つ以上の試験片表面に錆びが認められるまでの食塩水の噴霧時間である。
【００３２】
【表３】

【００３３】
（複合サイクル試験）
調製した試験片の片面に室温で５％食塩水を４時間連続噴霧後、相対湿度９５％、６０℃雰囲気下に２時間放置し、さらに相対湿度９５％、４０℃雰囲気下に２時間放置するという一連の８時間の試験を１サイクルとし、この試験を繰り返し行い、鋼鈑表面の赤錆の発生を観察した。結果を表３に示す、尚、表中の複合サイクル試験（サイクル数）は、試験数を各３とし、目視により内２つ以上の試験片表面に錆びが認められるまでの本試験の繰り返し数である。
【００３４】
【発明の効果】
表３から明らかなように、本発明により製造される耐食性鉄材は、有害なクロム化合物含有することなく高い耐食性およびその耐久性を示す。従って、本発明により製造される耐食性鉄材は建築材、建設機械、船舶、舟艇、橋梁、自動車、車輌等の部材に好適であり、広く利用できる。[0001]
[Industrial applications]
The present invention relates to a method for producing a corrosion-resistant iron material. More specifically, the present invention relates to a method for producing a high corrosion-resistant iron material suitable for a site requiring high corrosion resistance, such as a building material, a construction machine, a ship, a boat, a bridge, an automobile, a vehicle, and the like.
[0002]
[Prior art]
Conventionally, iron rust prevention processing has been widely performed, coating with various paints to block oxygen and water, coating with metals such as nickel, copper, chromium, cadmium, zinc, aluminum, tin, enamel, chromic acid Inorganic coatings typified by chemical conversion treatment with salts and phosphates, and electrolytic protection methods have been put to practical use.
[0003]
In particular, when high rust prevention performance is particularly required, the surface of the iron material is first coated with zinc or aluminum-based metal to form an undercoat layer, and then overcoated with a chromic acid-based chemical conversion treatment (chromate treatment) as a high corrosion resistance processing method. Then, a method of further providing a protective layer of a paint, if necessary, has been put to practical use. However, although treatment with chromium is extremely effective in preventing rust, hexavalent chromium contained is harmful to the human body and causes liver failure, skin ulcers, rhinitis, asthma, etc., and has recently become a social problem. .
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a corrosion-resistant iron material having high rust prevention and durability without using or containing a harmful chromium-based compound.
[0005]
[Means to solve the problem]
The object of the present invention is to apply a rust-preventive coating composition containing the following (a) and (b) as essential components to the surface of an iron material coated with an undercoating agent containing at least one selected from zinc and aluminum as a main component. The protective layer is cured by room temperature treatment or heat treatment, and further coated with an overcoating composition containing the following (c) as an essential component, and cured by room temperature treatment or heat treatment to form a protective layer.
(A) a compound having at least one phenolic hydroxyl group in the molecule (b) one or more silane compounds represented by the following general formula (1), and two or more silane compounds represented by the general formula (1) A mixture of two or more kinds, or a condensation product of a mixture of two or more kinds of silane compounds represented by the general formula (1), or a mixture thereof;
[0006]
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[0007]
In the formula, R ¹ is a monovalent group having a glycidoxy group or an epoxycycloalkyl group having 5 or 6 carbon atoms; R ² is a monovalent lower alkyl group having 1 to 6 carbon atoms; X is alkoxy having 1 to 6 carbon atoms And a represents 0, 1 or 2.
[0008]
(C) A silicate represented by the general formula (2) and a compound having at least one or more siloxane bonds selected from the group of silicates represented by the general formula (3) and / or a condensate thereof.
[0009]
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[0010]
In the formula, R ³ is a group selected from the group consisting of a hydrogen atom and a monovalent lower hydrocarbon group having 1 to 6 carbon atoms (however, when there are a plurality of R ^{3 s} , they may be the same or different); b is an integer of 1 or more.
[0011]
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[0012]
In the formula, M is a group selected from the group consisting of alkali metals and ammoniums (however, when there are a plurality of M, they may be the same or different); and n is an integer of 1 or more.
[0013]
Further, the above-mentioned object of the present invention is to provide a co-condensate of one or more of silicates represented by the formula (2) and silane compounds represented by the following formula (4), respectively, This is achieved by applying the composition and curing it by room temperature treatment or heat treatment.
[0014]
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[0015]
In the formula, R ⁴ is a carbon atom having at least one functional group selected from a glycidoxy group, an epoxycycloalkyl group having 5 or 6 carbon atoms, a (meth) acryl group, an amino group, a mercapto group, an aryl group, and a cycloalkyl group. monovalent group having 1 to 18; an alkenyl group having 2 to 18 carbon atoms; alkyl group having 1 to 18 carbon atoms is or halogen-substituted alkyl group having 1 to 18 carbon atoms, R ⁵ is 1 to 6 carbon atoms Y is an alkoxy group having 1 to 6 carbon atoms; a ketoxime group having 1 to 6 carbon atoms; or an acetoxy group having 1 to 6 carbon atoms, and c represents an integer of 0, 1 or 2. .
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
The undercoat layer in the present invention is a film made of a metal containing at least one selected from zinc and aluminum having a higher ionization tendency than iron, and serves as a sacrificial anode to prevent oxidation of the iron material. The undercoat layer made of these metals can be formed by a method such as hot dipping, electroplating, infiltration plating, chemical plating, and thermal spraying, and application of a paint containing fine powder of these metals.
Examples of the compound having at least one phenolic hydroxyl group in the same molecule of the component (a) in the rust preventive coating composition used in the present invention include phenol, cresol, thymol, bromophenol, naphthol, anilinophenol and the like. Dihydric phenols represented by monohydric phenols, pyrocatechin (catechol), resorcin, hydroquinone, orcin, urushiol, bisphenol A, binaphthol, pyrogallol, phloroglucin, hydroxyhydroquinone, trihydroxybenzoic acid, etc. Examples thereof include, but are not limited to, trihydric phenols, polyhydric phenols such as tannic acid and phenol-formaldehyde condensate. These compounds having at least one phenolic hydroxyl group in the same molecule can be used alone or in combination of two or more. These phenols react with iron to form an iron salt to form a complex compound, which reduces the permeation of oxygen, thereby suppressing the oxidation of the primer. As a result, it is considered that the deterioration of the performance of the undercoat layer as a sacrificial anode is suppressed, so that the high corrosion resistance of the iron material is obtained. However, since these phenols are highly water-soluble, if used alone as the intermediate coating layer, for example, when the top coating layer is damaged, the phenols are eluted by water immersion or the like, resulting in insufficient corrosion protection durability.
[0017]
The silane compound (b) represented by the general formula (2) is used for preventing the elution of the phenols and forming a durable anticorrosive coating film. The silane compound (b) is condensed with the phenols to form a high molecular weight, so that the phenols are prevented from being eluted, and the epoxy group contained in the molecule of the silane compound allows the silane compound to be added to the metal-containing undercoat layer. It is considered that since the adhesion is improved, the anticorrosion durability is improved due to a synergistic effect of these.
As the silane compound represented by the general formula (2), (3-glycidoxypropyl) dimethylethoxysilane (3-glycidoxypropyl) methyldiethoxysilane (3-glycidoxypropyl) dimethylmethoxysilane (3-glycidyl) (Xypropyl) methyldimethoxysilane (3-glycidoxypropyl) trimethoxysilane 5,6-epoxyhexyltriethoxysilane 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane 2- (3,4-epoxycyclohexyl) Examples include, but are not limited to, ethyltriethoxysilane.
[0018]
The component (c) used as the top coat composition of the present invention is one in which silanol groups are dehydrated and condensed by drying, and a strong coating is formed by three-dimensional crosslinking to protect the rust-preventive coating. The silicate represented by the formula (2) is generally an oligomer obtained by dehydration condensation of an alkoxide of silicon. Although the structure and molecular weight of the alkoxide are not particularly limited, methyl silicate obtained by dehydration condensation of tetramethoxysilane and ethyl silicate obtained by dehydration condensation of tetraethoxysilane are easily available and have high reactivity and are suitable. Examples of the silicates represented by the formula (3) include alkali metal salts such as lithium silicate, sodium silicate and potassium silicate, and silicate amines such as methyltripropanolammonium silicate and dimethyldipropanolammonium silicate. Is exemplified.
[0019]
These compounds having a siloxane bond represented by the formulas (2) and (3) can be used alone or in combination of two or more. Further, these compounds having a siloxane bond represented by the formulas (2) and (3) may be used alone or as a mixture of two or more kinds, and further subjected to a condensation reaction to be used as a high molecular weight product and / or a co-condensate. You can also.
[0020]
Further, when the corrosion-resistant iron material obtained in the present invention is used in a harsh environment such as high temperature salt water, acidic salt water or alkaline salt water, the compound having a siloxane bond represented by the formula (2) or (3) is used. For the purpose of further increasing the durability of the condensed protective layer, a co-condensate of a compound having a siloxane bond represented by formulas (2) and (3) and a silane compound represented by formula (4) is used. can do. A co-condensate of a compound having a siloxane bond represented by the formulas (2) and (3) and a silane compound represented by the formula (4) is obtained by combining a compound having a siloxane bond represented by the formulas (2) and (3) with a compound represented by the formula It can be obtained by applying a compound condensed in advance with the compound represented by the formula (4) and curing it by a room temperature treatment or a heat treatment, and when represented by the formulas (2) and (3), it is represented by the formula (4) It can also be obtained by applying a mixture of compounds and curing it by a room temperature treatment or a heat treatment.
Examples of the silane compound represented by the general formula (4) include trimethylchlorosilanetrimethylmethoxysilanemethyltris (methylethylketoxime) silanedimethyldiacetoxysylandedecyltriethoxycylandedecylmethyldichlorosilane3-chloropropyltrichlorosilane3-chloropropyltrimethoxysilane3 -Chloropropyldimethylchlorosilane 3-chloropropyldimethylmethoxysilanechloromethyldimethylchlorosilanechloromethyldimethylisopropoxysilane 11-bromoundecyldimethylchlorosilanevinyltris (methylethylketoxime) silanevinylmethyldimethoxysilanevinyldiphenylethoxysilaneallyldimethylmethoxysilaneallyldimethyl Chlorosilane 3- (N-allylamino) propyltri Toxisilane (3-glycidoxypropyl) dimethylethoxysilane (3-glycidoxypropyl) methyldiethoxysilane (3-glycidoxypropyl) dimethylmethoxysilane (3-glycidoxypropyl) methyldimethoxysilane (3-glycidyl) Sidoxypropyl) trimethoxysilane 5,6-epoxyhexyltriethoxysilane 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane (3-acryloxypropyl) ) Dimethylchlorosilane (3-acryloxypropyl) methyldimethoxysilane (3-methacryloxypropyl) methyldichlorosilane (3-methacryloxypropyl) methyldimethoxysilane N- (2-aminoethyl) -3-aminopro Dimethylmethoxysilane N- (6-aminohexyl) aminopropylmethyldimethoxysilane mercaptomethyldimethylmethoxysilane 3-mercaptopropylmethyldiethoxysilanephenylethyldichlorosilanephenyldimethylchlorosilanephenethyldimethylmethoxysilane 3-phenoxypropyltrichlorosilanecyclohexylmethyldimethoxy Examples thereof include, but are not limited to, silanecyclooctyldimethylchlorosilane [2- (3-cyclohexenyl) ethyl] dimethylmethoxysilane.
[0021]
The compounding ratio of the components (a) and (b) in the rust-preventive coating composition used for the intermediate coating of the corrosion-resistant iron material of the present invention may be determined according to the required rust-preventive performance, and is not particularly limited. However, from the viewpoint of coatability and cured film strength of the composition of the present invention, the weight mixing ratio (I) :( II) of the component (A) and the component (B) is more preferably from 20:80 to 80:20. Is in the range of 40:60 to 60:40.
[0022]
The rust preventive coating composition used as the intermediate coating agent is applied to an iron material whose surface is coated with an undercoat agent containing at least one selected from zinc and aluminum by spraying, dipping, brush coating, printing, or the like. can do. The coating amount is usually 5 to 200 μm in dry film thickness, but is not limited thereto.
[0023]
After the rust-preventive coating composition is applied, a cured coating film can be obtained by heating at room temperature for 2 to 10 hours or at 150 ° C. for 30 minutes to 1 hour. Further, the top coat composition can be similarly applied to the surface of the iron material coated with the rust preventive coating composition and cured to form a protective layer.
[0024]
Further, the rust-preventive coating composition of the present invention may contain other additives in an appropriate amount as long as the properties of the composition of the present invention are not impaired. As other additives, added for the purpose of speeding up the curing, curing catalyst such as metal alkoxide, water added for the purpose of adjusting the viscosity, diluting solvents such as alcohols, ketones, glycols, glass, Inorganic fillers such as quartz, aluminum hydroxide, alumina, kaolin, talc, calcium carbonate, calcium silicate, magnesium hydroxide, etc .; organic fillers such as acrylic resin powder, epoxy resin powder, polyester resin powder, carbon black, red iron, phthalocyanine Examples include coloring agents represented by pigments or dyes such as blue, chrome yellow, and titanium dioxide, metal powders, lubricants, release agents, surfactants, coupling agents, and the like, but are not limited thereto. Absent.
[0025]
Furthermore, various paints and coating agents can be applied to the corrosion-resistant iron material manufactured according to the present invention for the purpose of protecting, decorating, and coloring the surface.
[0026]
【Example】
Hereinafter, typical examples of the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the examples, “parts” means “parts by weight”.
[Examples 1-3, Comparative Examples 1-2: Preparation of rust-preventive coating composition]
Each rust-preventive coating composition was manufactured according to the raw material component formulation in Table 1.
[0027]
[Table 1]

[0028]
Each raw material component shown in Table 1 was placed in an Erlenmeyer flask, stirred and mixed at room temperature for 30 minutes, further stirred at 60 ° C. for 2 hours, allowed to cool to room temperature, and filtered through a nylon mesh having openings of 50 μm. A rust preventive coating composition was obtained. In addition, the raw material components (A) to (G) in the table are as shown below.
(A) 3,4,5-trihydroxybenzoic acid ethyl ester (Kanto Chemical Co., Ltd.)
(B) 1,2-benzenediol (Kanto Chemical Co., Ltd.)
(C) 3-glycidoxypropyltrimethoxysilane (S510 Chisso Corporation)
(D) 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane (S530 Chisso Corporation)
(E) 3-methacryloxypropyltrimethoxysilane (S710 Chisso Corporation)
(F) 99.5% ethanol (Kanto Chemical Co., Ltd.)
(G) Purified water (Kanto Chemical Co., Ltd.)
[Examples 4 to 9, Comparative Examples 3 to 4: Preparation of overcoat coating composition]
Each top coat composition was produced according to the raw material component formula in Table 1.
[0029]
[Table 2]

[0030]
Each raw material component shown in Table 2 was placed in an Erlenmeyer flask, stirred and mixed at room temperature for 30 minutes, further stirred and mixed at 60 ° C. for 2 hours, allowed to cool to room temperature, and filtered through a nylon mesh having openings of 50 μm. Was obtained. In addition, the raw material components (H) to (S) in the table are as shown below.
(H) Methyl silicate (MS-51 Mitsubishi Chemical Corporation)
(I) Ammonium silicate (Amine silicate CAS 25 Nissan Chemical Industries, Ltd.)
(J) Trimethylmethoxysilane (AY43-043 Dow Corning Toray Silicone Co., Ltd.)
(K) N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane (S310 Chisso Corporation)
(L) 3-glycidoxypropylmethyldimethoxysilane (S520 Chisso Corporation)
(M) Methyl tris (methyl ethyl ketoxime) silane (MTO Toray)
(N) 99.5% ethanol (Kanto Chemical Co., Ltd.)
(O) Purified water (Kanto Chemical Co., Ltd.)
(Preparation of test piece)
Using the rust-preventive coating composition and the overcoating composition prepared as described above, test pieces were prepared as follows.
[0031]
After cleaning the surface of a 25 × 100 × 2 mm steel plate by a shot blast method, zinc was applied by a thermal spraying method so that the adhesion amount became 20 g / m ² . The zinc-treated steel sheet was immersed in the composition shown in Table 1 for 10 minutes, pulled up, dried at room temperature for 30 minutes, further dried in an oven at 150 ° C. for 1 hour, and allowed to cool to room temperature. Immersed in the sample for 10 minutes, pulled up, dried at room temperature for 30 minutes, and further dried in a 150 ° C. oven for 1 hour to obtain a test piece.
(Salt spray test)
One side of the test piece prepared as described above was continuously sprayed with 5% saline, and the occurrence of red rust on the steel sheet surface was observed. Table 3 shows the results. In addition, the salt water spray test (time) in the table is the spray time of the salt solution until rust is visually observed on two or more of the test pieces, with the number of tests being three.
[0032]
[Table 3]

[0033]
(Compound cycle test)
One side of the prepared test piece is continuously sprayed with 5% saline at room temperature for 4 hours, and then left for 2 hours in an atmosphere of 60% with a relative humidity of 95%, and further left for 2 hours in an atmosphere of 40% with a relative humidity of 95%. A series of 8 hour tests was defined as one cycle, and this test was repeated, and the occurrence of red rust on the steel sheet surface was observed. The results are shown in Table 3. In the composite cycle test (cycle number) in the table, the number of tests was 3 and the number of repetitions of this test until rust was visually observed on at least two of the test specimen surfaces. It is.
[0034]
【The invention's effect】
As is clear from Table 3, the corrosion-resistant iron material produced according to the present invention exhibits high corrosion resistance and its durability without containing harmful chromium compounds. Therefore, the corrosion-resistant iron material manufactured by the present invention is suitable for building materials, construction machines, ships, boats, bridges, automobiles, vehicles and the like, and can be widely used.

Claims (3)

A rust-preventive coating composition containing the following (a) and (b) as essential components is applied to the surface of an iron material whose surface is coated with an undercoat agent containing at least one selected from zinc and aluminum as a main component, and A method for producing a corrosion-resistant iron material, wherein the composition is cured by a treatment or a heat treatment, and a top coat composition containing the following (c) as an essential component is applied as a protective layer and cured by a room temperature treatment or a heat treatment.
(A) a compound having at least one phenolic hydroxyl group in the molecule;
(B) The silane compound represented by the following general formula (1) alone, a mixture of two or more silane compounds represented by the general formula (1), and two or more silane compounds represented by the general formula (1) A condensation product of a mixture of the above, or a mixture thereof;

(Wherein, R ¹ is a monovalent group having a glycidoxy group or an epoxycycloalkyl group having 5 or 6 carbon atoms, R ² is a monovalent lower alkyl group, X is an alkoxy group, and a is 0, 1, or 2. Represents.)
(C) silicates represented by the following general formula (2), silicates represented by the following general formula (3), mixtures thereof, or condensates thereof;

(Wherein, R ³ is a group selected from the group consisting of a hydrogen atom and a monovalent lower hydrocarbon group. However, when there are a plurality of R ^{3 s} , they may be the same or different, and b is 1 or more. It is an integer.)

(Wherein, M is a group selected from the group consisting of alkali metals and ammoniums, provided that when M is plural, they may be the same or different, and n is an integer of 1 or more.) The overcoat coating composition is a co-condensate of one or more silicates represented by the formula (2) and one or more silane compounds represented by the following formula (4) The method for producing a corrosion-resistant iron material according to claim 1, which is a coating composition containing, as an essential component.

(Wherein, R ⁴ has one or more functional groups selected from a glycidoxy group, an epoxycycloalkyl group having 5 or 6 carbon atoms, a (meth) acryl group, an amino group, a mercapto group, an aryl group, and a cycloalkyl group. monovalent group having 1 to 18 carbon atoms; an alkenyl group having 2 to 18 carbon atoms; alkyl group having 1 to 18 carbon atoms is or halogen-substituted alkyl group having 1 to 18 carbon atoms, R ⁵ is 1 to carbon atoms 6 is a lower alkyl group, Y is an alkoxy group having 1 to 6 carbon atoms; a ketoxime group having 1 to 6 carbon atoms; or an acetoxy group having 1 to 6 carbon atoms, and c is an integer of 0, 1 or 2. Represents.) The method for producing a corrosion-resistant iron material according to claim 1, wherein the rust-preventive coating composition is a coating composition containing component (a) and component (b) in a weight ratio of 20:80 to 80:20.