JPWO2002061005A1 - Coating agent for forming titanium oxide film, method for forming titanium oxide film, and metal substrate coated with titanium oxide film - Google Patents

Abstract

The present invention relates to (A) a specific titanium-containing aqueous liquid and (B) a coating agent for forming a titanium oxide film containing a phosphoric acid compound, and (A) a titanium-containing aqueous liquid and (B ′) a phosphoric acid compound. And (C) a coating agent for forming a titanium oxide film, containing (C) an aqueous organic polymer compound stable at a pH of 7 or less. The present invention also provides a method for forming a titanium oxide film using any one of the above-described coating agents for forming a titanium oxide film, and a metal substrate coated with the titanium oxide film.

Description

本発明酸化チタン膜形成用塗布剤Ｉの性能試験
実施例１〜１６及び比較例１〜２で得た各塗布剤を用いて、金属基材の被覆処理を行い、得られた被覆基材の耐食性を調べた。
（１）アルミニウム板の被覆処理
板厚０．１ｍｍのアルミニウム板（Ａ１０５０）を、アルカリ脱脂剤（日本シービーケミカル（株）製、商品名「ケミクリーナー５６１Ｂ」）を溶解した濃度２％の水溶液を使用して脱脂、水洗した後、各塗布剤を乾燥被膜重量が０．２ｇ／ｍ^２になるようにローラー塗装し、素材到達温度が１００℃になるようにして２０秒間焼付けて、酸化チタン被膜を形成した。
（２）被覆板の耐食性
上記各被覆板について、ＪＩＳ Ｚ２３７１の塩水噴霧試験法に準じて測定した。試験時間は１２０時間、２４０時間、３６０時間及び４８０時間の４段階とし、下記基準により評価した。
ａ…塗面に白サビ、フクレの発生が認められない、
ｂ…白サビ又はフクレが少し発生、
ｃ…白サビ又はフクレが著しく発生。
試験結果を表２に示す。

（３）鋼板の被覆処理
板厚０．６ｍｍの電気亜鉛めっき鋼板（片面のめっき付着量２０ｇ／ｍ^２）を、アルカリ脱脂剤（日本シービーケミカル（株）製、商品名「ケミクリーナー５６１Ｂ」）を溶解した濃度２％の水溶液を使用して脱脂、水洗した後、各塗布剤を乾燥被膜重量が１．０ｇ／ｍ^２となるようにローラー塗装し、素材到達温度が１００℃になるようにして２０秒間焼付けて、酸化チタン被膜を形成した。
（４）被覆板の耐食性
上記各被覆板の端面部及び裏面部をシールした試験塗板について、ＪＩＳ Ｚ２３７１の塩水噴霧試験法に準じて測定した。試験時間は２４時間、４８時間及び７２時間の３段階とし、下記基準により評価した。
ａ：白錆の発生が認められない、
ｂ：白錆の発生程度が塗膜面積の５％未満、
ｃ：白錆の発生程度が塗膜面積の５％以上で１０％未満、
ｄ：白錆の発生程度が塗膜面積の１０％以上で５０％未満、
ｅ：白錆の発生程度が塗膜面積の５０％以上。
試験結果を表３に示す。

（５）鋼板の被覆処理
板厚０．６ｍｍの電気亜鉛めっき鋼板（片面のめっき付着量２０ｇ／ｍ^２）の表面を、アルカリ脱脂した後、「プレパレンＺ」（日本パーカライジング（株）製、商品名）をスプレー塗装して表面調整を行った。ついで、「パルボンド３３０８」（日本パーカライジング（株）製、商品名、リン酸亜鉛水溶液）をスプレー塗装した後、水洗、乾燥してリン酸亜鉛処理を施しためっき鋼板を得た。リン酸亜鉛処理被膜の付着量は１．５ｇ／ｍ^２とした。
上記リン酸亜鉛処理を施しためっき鋼板表面に、前記各塗布剤を乾燥被膜重量が１．０ｇ／ｍ^２になるようにスプレー塗装し、素材到達温度が１００℃になるようにして２０秒間焼付けて、酸化チタン被膜を形成した。
（６）被覆板の耐食性
上記各被覆板の端面部及び裏面部をシールした試験塗板について、ＪＩＳ Ｚ２３７１の塩水噴霧試験法に準じて測定した。試験時間は２４時間、４８時間及び７２時間の３段階とし、下記基準により評価した。
ａ：白錆の発生が認められない、
ｂ：白錆の発生程度が塗膜面積の５％未満、
ｃ：白錆の発生程度が塗膜面積の５％以上で１０％未満、
ｄ：白錆の発生程度が塗膜面積の１０％以上で５０％未満、
ｅ：白錆の発生程度が塗膜面積の５０％以上。
試験結果を表４に示す。

水性有機高分子化合物（Ｃ）の調製
製造例８
温度計、攪拌械、冷却器、滴下ロートを備えた１Ｌの四ツ口フラスコに、イソプロピルアルコール１８０部を入れ、窒素置換の後、フラスコ内の温度を８５℃に調整し、エチルアクリレート１４０部、メチルメタクリレート６８部、スチレン１５部、Ｎ−ｎ−ブトキシメチルアクリルアミド１５部、２−ヒドロキシエチルアクリレート３８部及びアクリル酸２４部よりなる単量体混合物を、触媒の２，２′−アゾビス（２，４−ジメチルワレロニトリル）６部とともに約２時間を要して滴下した。滴下終了後同温度で、さらに５時間反応を続けると重合率がほぼ１００％、固形分約６３％、酸価約６７ｍｇＫＯＨ／ｇの無色透明な樹脂溶液が得られた。この樹脂溶液５００部に対してジメチルアミノエタノール１０８部を混合し、水を加えて十分に攪拌することによって、固形分３０％のアクリル樹脂水分散液（Ｃ１）を得た。
製造例９
攪拌装置、還流冷却器、温度計、液体滴下装置を備えた反応装置に、「エピコート１００９」（シェル化学社製、商品名、分子量３，７５０のエポキシ樹脂）１，８８０ｇ（０．５モル）とメチルイソブチルケトン／キシレン＝１／１（重量比）の混合溶媒１，０００ｇを加えた後、攪拌加熱し、均一に溶解した。その後７０℃まで冷却し、液体滴下装置に分取したジ（ｎ−プロパノール）アミン７０ｇを３０分間を要して滴下した。この間、反応温度を７０℃に保持した。滴下終了後１２０℃で２時間保持し、反応を完結させることにより、固形分６６％のアミン変性エポキシ樹脂を得た。得られた樹脂１，０００ｇに対して８８％の蟻酸２５部を混合し、水を加えて十分に攪拌することによって、固形分３０％のアミン変性エポキシ樹脂水分散液（Ｃ２）を得た。
本発明酸化チタン膜形成用塗布剤ＩＩの例
実施例１７
製造例１で得たチタン含有水性液（１）５０部、２０％ジルコニウム弗化水素酸５部、３０％アクリル樹脂水分散液（Ｃ１）１０部及び脱イオン水３５部を混合して、本発明の酸化チタン膜形成用塗布剤を得た。
実施例１８〜２７及び比較例３〜５
表５に示す組成に基づき、実施例１７と同様にして、本発明の塗布剤及び比較用の塗布剤を得た。

上記表５において、「サランラテックスＬ−４１１」及び「クラレＲＳポリマーＲＳ−１０５」は、下記のものを示す。
サランラテックスＬ−４１１：旭化成工業（株）製、商品名、塩化ビニリデン樹脂、固形分５０％。
クラレＲＳポリマーＲＳ−１０５：クラレ（株）製、商品名、ポリビニルアルコール、固形分１０％。
本発明酸化チタン膜形成用塗布剤ＩＩの性能試験
実施例１７〜２７及び比較例３〜５で得た各塗布剤を用いて、鋼板基材の防錆被覆処理を行い、得られた被覆鋼板の塗膜外観、密着性及び耐食性を調べた。
（１）鋼板基材の防錆被覆処理
板厚０．８ｍｍの各種めっき鋼板を、基材として用いた。使用しためっき鋼板は、下記の６種類である。
（ｉ）電気亜鉛めっき鋼板：めっき付着量２０ｇ／ｍ^２、これを「ＥＧ」という、
（ｉｉ）溶融亜鉛めっき鋼板：めっき付着量６０ｇ／ｍ^２、これを「ＨＤＧ」という、
（ｉｉｉ）亜鉛−鉄合金めっき鋼板：めっき中のＦｅ量１０％、めっき付着量６０ｇ／ｍ^２、これを「Ｚｎ−Ｆｅ」という、
（ｉｖ）亜鉛−ニッケル合金めっき鋼板：めっき中のＮｉ量１２％、めっき付着量３０ｇ／ｍ^２、これを「Ｚｎ−Ｎｉ」という、
（ｖ）亜鉛−アルミニウム合金めっき鋼板：めっき中のＡｌ量１２％、めっき付着量１５０ｇ／ｍ^２、これを「Ｚｎ−１２％Ａｌ」という、
（ｖｉ）亜鉛−アルミニウム合金めっき鋼板：めっき中のＡｌ量５５％、めっき付着量２５０ｇ／ｍ^２、これを「Ｚｎ−５５％Ａｌ」という。
上記各めっき鋼板の表面を、アルカリ脱脂剤（日本シービーケミカル（株）製、商品名「ケミクリーナー５６１Ｂ」）を溶解した濃度２％の水溶液を、液温６５℃で２０秒間スプレーして脱脂後、６０℃の温水を２０秒間スプレーして洗浄した。この脱脂しためっき鋼板に、各塗布剤を乾燥被膜重量が０．５ｇ／ｍ^２となるようにスプレー塗装し、雰囲気温度２５０℃で１５秒間（素材到達温度が１００℃）乾燥して、防錆被膜を形成し、被覆鋼板を得た。
（２）被覆鋼板の性能試験
上記で得られた各被覆鋼板について、下記試験方法に基いて、塗膜外観、密着性及び耐食性の試験を行った。
試験方法
塗膜外観：被膜の均一性について目視にて下記基準に基づいて評価した。
ａ：ムラがなく均一な外観である、
ｂ：ムラが部分的にある、
ｃ：ムラが全面にある。
密着性：被膜について、ＪＩＳ Ｋ５４００の８．５．２に記載の碁盤目テープ法（すきま間隔１ｍｍ）を行い、下記基準により密着性を評価した。
ａ：被膜の剥離が全く認められない、
ｂ：被膜の剥離が認められるが、剥離面積は５％未満、
ｃ：剥離面積が５％以上で２０％未満、
ｄ：剥離面積が２０％以上で５０％未満、
ｅ：剥離面積が５０％以上。
耐食性：被覆鋼板の端面部及び裏面部をシールし、ＪＩＳ Ｚ２３７１に規定する塩水噴霧試験を２４時間、４８時間及び７２時間の３段階で行い、下記基準により耐食性を評価した。
ａ：塗面に白錆及びフクレの発生が認められない、
ｂ：白錆又はフクレの発生程度が塗膜面積の１０％未満、
ｃ：白錆又はフクレの発生程度が塗膜面積の１０％以上で３０％未満、
ｄ：白錆又はフクレの発生程度が塗膜面積の３０％以上で５０％未満、
ｅ：白錆又はフクレの発生程度が塗膜面積の５０％以上。
試験結果を、表６に示す。

本発明酸化チタン膜形成用塗布剤ＩＩの例
実施例２８
製造例１で得たチタン含有水性液（１）５０部、２０％ジルコニウム弗化水素酸５部、「ＡＣ１０ＬＰ」（日本化薬（株）製、ポリアクリル酸水溶液、重量平均分子量２５，０００、酸価７７９ｍｇＫＯＨ／ｇ、固形分１０％）３０部及び脱イオン水１５部を混合して、本発明の酸化チタン膜形成用塗布剤を得た。
実施例２９〜３３及び比較例６〜７
表７に示す組成に基づき、実施例２８と同様にして、本発明の塗布剤及び比較用の塗布剤を得た。

上記表７において、「ＡＣ１０ＬＰ」、「デンカポバールＫ−０５」及び「ＰＥＧ６０００Ｓ」は、下記のものを示す。
ＡＣ１０ＬＰ：日本化薬（株）製、商品名、ポリアクリル酸水溶液、重量平均分子量２５，０００、酸価７７９ｍｇＫＯＨ／ｇ、固形分１０％。
デンカポバールＫ−０５：電気化学工業（株）製、商品名、ポリビニルアルコール、ケン化度９９％、重合度５５０、固形分１０％。
ＰＥＧ６０００Ｓ：三洋化成工業（株）製、商品名、ポリエチレングリコール、平均分子量８，３００、固形分１０％。
本発明酸化チタン膜形成用塗布剤ＩＩの性能試験
実施例２８〜３３及び比較例６〜７で得た各塗布剤を用いて、アルミニウム基材の防錆被覆処理を行い、得られた被覆アルミニウム板の塗膜外観、親水性及び耐食性を調べた。
（１）アルミニウム基材の防錆被覆処理
板厚０．１ｍｍのアルミニウム板（Ａ１０５０）を、アルカリ脱脂剤（日本シービーケミカル（株）製、商品名「ケミクリーナー５６１Ｂ」）を溶解した濃度２％の水溶液を使用して脱脂、水洗した後、乾燥膜厚５μｍとなるように、３０℃の各塗布剤中に３０秒間浸漬塗装し、１６０℃で１０分間焼付けて防錆被膜を形成し、被覆アルミニウム板を得た。
（２）試験塗板の性能試験
上記各被覆アルミニウム板について、下記試験方法に基いて、塗膜外観、親水性及び耐食性の試験を行った。
塗膜外観：防錆被膜の均一性について目視にて下記基準に基づいて評価した。
ａ：ムラがなく均一な外観である、
ｂ：ムラが部分的にある、
ｃ：ムラが全面にある。
親水性：被覆アルミニウム板を水道水流水（流水量は塗板１ｍ^２当り１５ｋｇ／ｈｒ）中に７２時間浸漬した後の水接触角により、親水性を評価した。また、比較の為、この試験を行う前の初期試験板についても、水接触角を測定した（初期親水性）。水接触角は、被覆アルミニウム板を８０℃で５分間乾燥したのち、被覆アルミニウム板の塗面上に注射器にて０．０４ｃｃの脱イオン水を滴下し水滴を形成し、水滴の接触角を協和科学（株）製「コンタクタングルメーターＤＣＡＡ型」にて測定した。水接触角が大きいほど、親水性が大きいことを示す。
耐食性：上記各被覆アルミニウム板について、ＪＩＳ Ｚ２３７１の塩水噴霧試験法に準じて測定した。試験時間は１２０時間及び２４０時間の２段階とし、下記基準により耐食性を評価した。
ａ：塗面に白錆及びフクレの発生が認められない、
ｂ：白錆又はフクレの発生程度が塗膜面積の１０％未満、
ｃ：白錆又はフクレの発生程度が塗膜面積の１０％以上で３０％未満、
ｄ：白錆又はフクレの発生程度が塗膜面積の３０％以上で５０％未満、
ｅ：白錆又はフクレの発生程度が塗膜面積の５０％以上。
試験結果を、表８に示す。

本発明の酸化チタン膜形成用塗布剤、酸化チタン膜形成方法及び酸化チタン膜で被覆された金属基材によれば、次のような格別な効果が得られる。
（１）本発明塗布剤は、貯蔵安定性に優れる。その理由は、チタン含有水性液（Ａ）自体が安定であることと、該水性液（Ａ）がリン酸系化合物、チタンハロゲン化物等（Ｂ）又は（Ｂ’）と安定な錯体を形成することによるものと考えられる。
（２）本発明の酸化チタン膜形成用塗布剤を用いた酸化チタン膜形成方法によれば、金属基材上に、耐食性、密着性、耐久性、加工性、親水性等に優れる酸化チタンを含む被膜を形成できる。
この被膜が耐食性や耐久性に優れるのは、基材に対する密着性が優れること、緻密な酸化チタン膜であるので酸素透過性や水蒸気透過性が小さいこと、リン酸系化合物、チタンハロゲン化物等（Ｂ）又は（Ｂ’）が金属に対するエッチング剤及び腐食抑制剤として機能すること、リン酸系化合物、チタンハロゲン化物等（Ｂ又はＢ’）が酸化チタンにより保護されること等によるものと考えられる。また、この被膜が密着性に優れるのは、被膜中の酸化チタンが水酸基を含んでいるためと考えられる。
（３）本発明酸化チタン膜形成方法を適用して得た被覆金属基材は、防錆被覆基材として、そのまま好適に使用することができる。
（４）本発明塗布剤を、アルミニウム又はアルミニウム合金基材の表面に塗装して被膜を形成した熱交換器用フィンによれば、冷房時に発生する凝縮水によるフィン間の水のブリッジ形成を防止できる。従って、アルミニウム又はアルミニウム合金製のフィンの腐食が防止できる。 Technical field
The present invention relates to a novel coating agent for forming a titanium oxide film, a method for forming a titanium oxide film, and a metal substrate coated with a titanium oxide film.
Background technology
BACKGROUND ART Metal substrates such as steel plates, aluminum, and aluminum alloys are usually subjected to various surface treatments as a base treatment in order to improve corrosion resistance, workability, and the like.
In recent years, since a surface-treated steel sheet is required to have better corrosion resistance, a zinc-based plated steel sheet is increasingly used as a substrate instead of a cold-rolled steel sheet.
Conventionally, a chromate treatment and a phosphate treatment are generally performed as a surface treatment of a galvanized steel sheet.
Chromate treatment has the problem of toxicity of chromium compounds. In particular, hexavalent chromium compounds are extremely harmful substances, as many public institutions have designated them as carcinogens for the human body, including IARC (International Agency for Research on Cancer Review). Specifically, the chromate treatment has problems such as the volatilization of chromate fume in the treatment process, the need for a large amount of wastewater treatment equipment, and the elution of chromic acid from the treated film.
In addition, in the phosphating treatment of zinc phosphate, iron phosphate, etc., after the phosphating treatment, the post-treatment is usually performed with chromate. There is also a problem of wastewater treatment of a reaction accelerator, metal ions and the like, and sludge treatment due to elution of metal ions from the metal to be treated.
Further, JP-A-58-224174, JP-A-60-50179, JP-A-60-50180, and the like, use a zinc-based plated steel sheet as a base material, form a chromate film thereon, A coated steel sheet on which an organic silicate coating is formed is described. This coated steel sheet has performance excellent in corrosion resistance and workability. However, since the coated steel sheet has a chromate film, there is still a problem of toxicity of the chromium compound. Further, the steel sheet obtained by removing the chromate film from the coated steel sheet has insufficient corrosion resistance.
On the other hand, various surface treatments are often performed on the aluminum or aluminum alloy base material as a base treatment in order to improve corrosion resistance, hydrophilicity, and the like.
For example, as a fin for a heat exchanger of an air conditioner, an aluminum or aluminum alloy base material excellent in light weight, workability, and heat conductivity is generally used. In the heat exchanger of this air conditioner, condensed water generated during cooling becomes water droplets and forms a water bridge between the fins, and the ventilation resistance increases because the air ventilation path is narrowed, resulting in loss of power and noise. There are problems such as generation and scattering of water droplets.
In order to solve this problem, the surface of the fin, which is an aluminum or aluminum alloy substrate, is subjected to a hydrophilic treatment such as boehmite treatment, water glass application, and aqueous polymer application to prevent the formation of the bridge. I have. However, fins made of aluminum or an alloy thereof which have been subjected to hydrophilization are corroded in a few months when placed in a strong corrosive environment, because the treated film has hydrophilicity.
Conventionally, as a method for preventing such fin corrosion, a method of subjecting a surface of an aluminum or aluminum alloy substrate to a chromate treatment as a base treatment is often performed in view of corrosion resistance, cost, and the like. However, the chromate treatment has a problem of toxicity of the chromium compound as described above.
Further, as a surface treatment agent or a surface treatment method that does not use chromate, for example, a method of treating an aluminum surface with an acidic solution containing a titanium salt, hydrogen peroxide and condensed phosphoric acid (JP-A-54-24232), A method in which an aluminum surface is treated with an alkaline aqueous solution containing titanium ions and a complexing agent, washed with water, and then treated with an acidic aqueous solution such as phosphoric acid (JP-A-54-160527), phosphate ions, titanium compounds and fluorine compounds. Surface treatment agent containing fluoride (JP-A-9-20984), aluminum-based metal surface treatment agent containing condensed phosphate, titanium salt, fluoride and phosphite (JP-A-9-143752) Etc. are known.
However, the surface treatment agent and the surface treatment method using the titanium compound described above have insufficient stability of the surface treatment agent, insufficient corrosion resistance as compared with chromate treatment, insufficient hydrophilicity, and durability. There were problems such as insufficient properties.
Under the circumstances described above, there has been a demand for an inorganic film-forming material capable of forming a film having excellent corrosion resistance and the like without causing a problem of toxicity as a base treatment agent for a metal substrate such as a steel plate, aluminum, and an aluminum alloy.
Disclosure of the invention
An object of the present invention is to provide a novel coating agent for forming a titanium oxide film and a method for forming a titanium oxide film, which can form a good coating such as corrosion resistance, adhesion, and workability on a metal substrate.
Another object of the present invention is to provide a metal substrate coated with a titanium oxide film having excellent corrosion resistance, adhesion, and workability.
Other objects and features of the present invention will become apparent from the following description.
The present invention provides the following novel coating material for forming a titanium oxide film, a method for forming a titanium oxide film, and a metal substrate coated with a titanium oxide film.
1. (A) Obtained by mixing at least one titanium compound selected from a hydrolyzable titanium compound, a low-condensate of a hydrolyzable titanium compound, titanium hydroxide and a low-condensate of titanium hydroxide with hydrogen peroxide. Titanium-containing aqueous liquid, and
(B) A coating composition for forming a titanium oxide film, comprising a phosphoric acid compound.
2. Item 2. The coating composition according to item 1, wherein the titanium-containing aqueous liquid (A) is an aqueous peroxotitanic acid solution obtained by mixing a hydrolyzable titanium compound and / or a low-condensate thereof with aqueous hydrogen peroxide.
3. The hydrolyzable titanium compound has a general formula
Ti (OR)₄                          (1)
The coating agent according to the above item 2, which is a tetraalkoxytitanium represented by the formula (wherein, R is the same or different and represents an alkyl group having 1 to 5 carbon atoms).
4. The low-condensation product of the hydrolyzable titanium compound has a general formula
Ti (OR)₄                          (1)
(Wherein R is the same or different and represents an alkyl group having 1 to 5 carbon atoms.) The above item which is a compound having a condensation degree of 2 to 30 obtained by subjecting tetraalkoxy titaniums represented by the following condensation reaction to each other. 3. The coating composition according to item 2.
5. The mixing ratio of the hydrolyzable titanium compound and / or the low-condensate thereof and the aqueous hydrogen peroxide is such that the latter is in the range of 0.1 to 100 parts by weight in terms of hydrogen peroxide with respect to 10 parts by weight of the former. Item 6. The coating agent according to Item 2.
6. The above item 2, wherein the titanium-containing aqueous liquid (A) is an aqueous peroxotitanic acid solution obtained by mixing a hydrolyzable titanium compound and / or a low-condensate thereof with aqueous hydrogen peroxide in the presence of a titanium oxide sol. The coating agent according to the above.
7. Item 7. The coating composition according to Item 6, wherein the titanium oxide sol is an aqueous dispersion of anatase-type titanium oxide.
8. Item 7. The coating agent according to Item 6, wherein the amount of the titanium oxide sol used is 0.01 to 10 parts by weight in terms of solid content based on 1 part by weight of the hydrolyzable titanium compound and / or its low-condensate.
9. Item 2. The coating according to item 1, wherein the phosphoric acid compound (B) is at least one compound selected from the group consisting of monophosphoric acids, derivatives and salts of monophosphoric acids, condensed phosphoric acids, derivatives of condensed phosphoric acids and salts. Agent.
10. Item 2. The coating agent according to item 1, wherein the content ratio of the titanium-containing aqueous liquid (A) and the phosphoric acid compound (B) is 1 to 400 parts by weight with respect to 100 parts by weight of the solid content of the former.
11. Item 2. The coating material for forming a titanium oxide film according to Item 1, which is an aqueous liquid having a pH of 1 to 7.
12. 2. The coating according to the above item 1, further comprising at least one halide selected from the group consisting of titanium halides, titanium halide salts, zirconium halides, zirconium halide salts, silicon halides and silicon halide salts. Agent.
13. (A) Obtained by mixing at least one titanium compound selected from a hydrolyzable titanium compound, a low-condensate of a hydrolyzable titanium compound, titanium hydroxide and a low-condensate of titanium hydroxide with hydrogen peroxide. Titanium-containing aqueous liquid,
(B ') at least one compound selected from the group consisting of phosphoric acid compounds, titanium halides, titanium halide salts, zirconium halides, zirconium halide salts, silicon halides and silicon halide salts; and
(C) A coating agent for forming a titanium oxide film, which comprises a stable aqueous organic polymer compound at a pH of 7 or less.
14． Item 14. The coating composition according to the above item 13, wherein the titanium-containing aqueous liquid (A) is an aqueous solution of peroxotitanic acid obtained by mixing a hydrolyzable titanium compound and / or a low-condensate thereof with a hydrogen peroxide solution.
15. The hydrolyzable titanium compound has a general formula
Ti (OR)₄                        (1)
15. The coating agent according to item 14, which is a tetraalkoxytitanium represented by the formula: wherein R is the same or different and represents an alkyl group having 1 to 5 carbon atoms.
16. The low-condensation product of the hydrolyzable titanium compound has a general formula
Ti (OR)₄                          (1)
(Wherein R is the same or different and represents an alkyl group having 1 to 5 carbon atoms.) The above item which is a compound having a condensation degree of 2 to 30 obtained by subjecting tetraalkoxy titaniums represented by the following condensation reaction to each other. 15. The coating agent according to 14.
17． The mixing ratio of the hydrolyzable titanium compound and / or the low-condensate thereof and the aqueous hydrogen peroxide is such that the latter is in the range of 0.1 to 100 parts by weight in terms of hydrogen peroxide with respect to 10 parts by weight of the former. Item 15. The coating agent according to Item 14.
18. The above item 14 wherein the titanium-containing aqueous liquid (A) is an aqueous peroxotitanic acid solution obtained by mixing a hydrolyzable titanium compound and / or a low-condensate thereof with aqueous hydrogen peroxide in the presence of a titanium oxide sol. The coating agent according to the above.
19. Item 18. The coating agent according to Item 18, wherein the titanium oxide sol is an aqueous dispersion of anatase-type titanium oxide.
20. Item 18. The coating composition according to the above item 18, wherein the amount of the titanium oxide sol used is 0.01 to 10 parts by weight in terms of solid content based on 1 part by weight of the hydrolyzable titanium compound and / or its low condensate.
21. Item 13. In the above item 13, wherein the phosphoric acid compound in the compound (B ′) is at least one compound selected from the group consisting of monophosphoric acids, derivatives and salts of monophosphoric acids, condensed phosphoric acids, derivatives and salts of condensed phosphoric acids. The coating agent according to the above.
22. Item 14. The coating material according to the above item 13, wherein in the compound (B ′), the titanium constituting the titanium halide, the titanium halide salt, the zirconium halide, the zirconium halide salt, the silicon halide and the halogen constituting the silicon halide salt is fluorine. .
23. Item 14. The coating agent according to Item 13, wherein the content ratio of the titanium-containing aqueous liquid (A) and the compound (B ′) is 1 to 400 parts by weight with respect to 100 parts by weight of the solid content of the former.
24. The aqueous organic polymer compound (C) is an epoxy resin, a phenol resin, an acrylic resin, a urethane resin, a polyvinyl alcohol resin, a polyoxyalkylene chain-containing resin, and an olefin-polymerizable unsaturated carboxylic acid copolymer resin. Item 14. The coating agent according to Item 13, which is at least one resin selected from the group consisting of:
25. Item 14. The coating composition according to Item 13, wherein the content of the aqueous organic polymer compound (C) is 10 to 2,000 parts by weight based on 100 parts by weight of the solid content of the titanium-containing aqueous liquid (A).
26. Item 14. The coating agent according to Item 13, which is an aqueous liquid having a pH of 1 to 7.
27. 14. A method for forming a titanium oxide film, comprising applying the coating material for forming a titanium oxide film according to the above item 1 or 13 to a metal base material and drying.
28. Item 14. A coated metal substrate on which a coating of the coating material for forming a titanium oxide film according to item 1 or 13 is formed on a surface of the metal substrate.
29. 29. The coated metal substrate according to the above item 28, wherein the thickness of the coating is 0.001 to 10 μm.
30. 29. The coated metal substrate according to the above item 28, wherein the metal substrate is a steel plate.
31. Item 29. The coated metal substrate according to Item 28, wherein the metal substrate is aluminum or an aluminum alloy.
The present inventor has made intensive studies to achieve the above object. As a result, the titanium oxide film-forming coating agent I containing the titanium-containing aqueous liquid (A) and the phosphate compound (B), or the titanium-containing aqueous liquid (A), the phosphate compound and / or titanium halogen According to the coating agent II for forming a titanium oxide film containing the compound (B ') and the aqueous organic polymer compound (C), the metal substrate has good corrosion resistance, adhesion, workability, etc. It has been found that a suitable film can be formed.
The present invention has been completed based on these new findings.
Coating agent for forming titanium oxide film
The coating agent I for forming a titanium oxide film of the present invention is an aqueous coating agent containing the above-mentioned (A) titanium-containing aqueous liquid and (B) a phosphate compound.
In the coating composition I of the present invention, at least one titanium compound selected from a hydrolyzable titanium compound, a low condensate of a hydrolyzable titanium compound, titanium hydroxide and a low condensate of titanium hydroxide, which is the component (A), is used. As the titanium-containing aqueous liquid obtained by mixing with the aqueous hydrogen peroxide, a known one can be appropriately selected and used.
The hydrolyzable titanium compound is a titanium compound having a hydrolyzable group directly bonded to a titanium atom, and generates titanium hydroxide by reacting with water such as water or steam. Further, in the hydrolyzable titanium compound, all of the groups bonded to the titanium atom may be hydrolyzable groups, or some of the hydrolyzable groups may be hydrolyzed hydroxyl groups. .
The hydrolyzable group is not particularly limited as long as it reacts with water to form a hydroxyl group, and examples thereof include a lower alkoxyl group and a group that forms a salt with a titanium atom. Examples of the group that forms a salt with a titanium atom include a halogen atom (such as chlorine), a hydrogen atom, and a sulfate ion.
Examples of the hydrolyzable titanium compound containing a lower alkoxyl group as the hydrolyzable group include tetraalkoxy titanium.
Representative examples of the hydrolyzable titanium compound having a group capable of forming a salt with titanium as the hydrolyzable group include titanium chloride and titanium sulfate.
The low condensate of the hydrolyzable titanium compound is a low condensate of the above hydrolyzable titanium compounds. The low-condensate may be either a group in which all of the groups bonded to the titanium atom are hydrolyzable groups or a group in which some of the hydrolyzable groups are hydrolyzed hydroxyl groups.
As the low condensate of titanium hydroxide, for example, orthotitanic acid (titanium hydroxide gel) obtained by reacting an aqueous solution such as titanium chloride or titanium sulfate with an aqueous alkali solution such as ammonia or caustic soda can be used.
As for the degree of condensation in the low-condensation product of the hydrolyzable titanium compound or the low-condensation product of titanium hydroxide, a compound having 2 to 30 compounds can be used, and a compound having a condensation degree of 2 to 10 is particularly preferable.
As the aqueous liquid (A), conventionally known aqueous liquids can be used without particular limitation as long as they are titanium-containing aqueous liquids obtained by reacting the titanium compound with aqueous hydrogen peroxide. Specifically, the following can be used.
(1) A peroxotitanic acid aqueous solution described in JP-A-63-35419 and JP-A-1-224220 obtained by adding aqueous hydrogen peroxide to a gel or sol of hydrous titanium oxide.
(2) A reaction between an aqueous solution of titanium chloride, titanium sulfate or the like and an aqueous alkali solution such as ammonia or caustic soda described in JP-A-9-71418 and JP-A-10-67516 is called orthotitanic acid. An aqueous liquid for forming a titanium oxide film, which is a yellow transparent viscous liquid obtained by precipitating a titanium hydroxide gel, separating the titanium hydroxide gel by decantation, washing with water, and adding aqueous hydrogen peroxide thereto.
(3) Hydrogen peroxide solution is added to an aqueous solution of an inorganic titanium compound such as titanium chloride or titanium sulfate described in JP-A-2000-247638 and JP-A-2000-247639 to form a peroxotitanium hydrate. The solution obtained by adding a basic substance to this is left or heated to form a precipitate of a peroxotitanium hydrate polymer, and after removing dissolved components other than water, hydrogen peroxide is allowed to act. Aqueous solution for forming a titanium oxide film obtained by the above method.
As the titanium-containing aqueous liquid (A), it is preferable to use an aqueous solution of peroxotitanic acid (A1) obtained by mixing a hydrolyzable titanium compound and / or a low-condensate thereof with aqueous hydrogen peroxide.
As the titanium compound, particularly, a general formula
Ti (OR)₄                          (1)
(Wherein, R is the same or different and represents an alkyl group having 1 to 5 carbon atoms). Examples of the alkyl group having 1 to 5 carbon atoms represented by R include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group and a tert- Butyl group and the like.
As the low condensate of the titanium compound, those having a condensation degree of 2 to 30 obtained by subjecting the compounds of the general formula (1) to condensation reaction with each other are preferable, and those having a condensation degree of 2 to 10 are preferable. It is more preferred to use.
The mixing ratio of the hydrolyzable titanium compound of the general formula (1) and / or a low-condensate thereof (hereinafter, these are simply referred to as “hydrolyzable titanium compound (T)”) and hydrogen peroxide water are as follows: For the former 10 parts by weight, the latter is preferably 0.1 to 100 parts by weight, particularly 1 to 20 parts by weight in terms of hydrogen peroxide. If the latter is less than 0.1 part by weight in terms of hydrogen peroxide, the formation of peroxotitanic acid becomes insufficient and cloudy precipitation occurs, which is not preferable. On the other hand, if it exceeds 100 parts by weight, unreacted hydrogen peroxide is likely to remain and dangerous active oxygen is released during storage.
The concentration of hydrogen peroxide in the aqueous hydrogen peroxide is not particularly limited, but is preferably in the range of 3 to 40% by weight from the viewpoint of easy handling.
The aqueous peroxotitanic acid solution is usually prepared by mixing the hydrolyzable titanium compound (T) with a hydrogen peroxide solution under stirring at a temperature of about 1 to 70 ° C. for about 10 minutes to 20 hours. Can be prepared. In this mixing, a water-soluble solvent such as methanol, ethanol, n-propanol, iso-isopropanol, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether can be used as necessary.
The aqueous peroxotitanic acid solution (A1) is obtained by mixing the hydrolyzable titanium compound (T) with a hydrogen peroxide solution, whereby the hydrolyzable titanium compound is hydrolyzed with water to produce a hydroxyl group-containing titanium compound. It is presumed that hydrogen peroxide is obtained by immediately coordinating hydrogen peroxide to the hydroxyl group-containing titanium compound to form peroxotitanic acid. This aqueous solution of peroxotitanic acid has high stability at room temperature and withstands long-term storage.
In addition, the aqueous solution of peroxotitanic acid (A2) obtained by mixing the hydrolyzable titanium compound (T) with aqueous hydrogen peroxide in the presence of the titanium oxide sol has the storage stability of the aqueous solution and the obtained titanium oxide film. It is preferable because the corrosion resistance and the like are improved. The reason is that, in the preparation of the aqueous solution, the hydrolyzable titanium compound (T) is adsorbed on the titanium oxide sol particles, and the adsorbed hydrolyzable titanium compound (T) undergoes a condensation reaction with hydroxyl groups generated on the particle surface. The hydrolyzable titanium compound itself undergoes a condensation reaction to form a polymer, and then is mixed with hydrogen peroxide to stabilize the resulting aqueous solution and cause gelation during storage. It is presumed that thickening and thickening are significantly prevented.
The titanium oxide sol is a sol in which amorphous titanium oxide fine particles and anatase type titanium oxide fine particles are dispersed in water. As the titanium oxide sol, an aqueous dispersion of anatase type titanium oxide is preferable from the viewpoint of corrosion resistance. The titanium oxide sol may contain, for example, an aqueous organic solvent such as an alcohol-based or alcohol-ether-based solvent as required, in addition to water.
As the titanium oxide sol, a conventionally known one can be used. As the titanium oxide sol, for example, amorphous titanium oxide fine particles in which a titanium oxide aggregate is dispersed in water, or an anatase type titanium oxide fine particle obtained by firing the titanium oxide aggregate to be used in water are used. Can be. If the amorphous titanium oxide is calcined at least at a temperature higher than the crystallization temperature of anatase, usually at a temperature higher than 200 ° C., the amorphous titanium oxide can be converted into anatase-type titanium oxide. Examples of the titanium oxide aggregates include (1) those obtained by hydrolyzing an inorganic titanium compound such as titanium sulfate and titanyl sulfate, and (2) those obtained by hydrolyzing an organic titanium compound such as titanium alkoxide. And (3) those obtained by hydrolyzing or neutralizing a titanium halide solution such as titanium tetrachloride.
Commercially available titanium oxide sols include, for example, “TKS-201” (trade name, manufactured by Teica Co., Ltd., aqueous sol of anatase-type titanium oxide fine particles having an average particle diameter of 6 nm), and “TKS-203” (Taika Co., Ltd.). ), Trade name, aqueous sol of anatase type titanium oxide fine particles having an average particle diameter of 6 nm), "TA-15" (trade name, manufactured by Nissan Chemical Industries, Ltd., aqueous sol of anatase type titanium oxide fine particles), "STS- 11 "(manufactured by Ishihara Sangyo Co., Ltd., trade name, aqueous sol of anatase-type titanium oxide fine particles) and the like.
When mixing the hydrolyzable titanium compound (T) and the hydrogen peroxide solution, the amount of the titanium oxide sol to be used is usually 0.1% in solid content with respect to 1 part by weight of the hydrolyzable titanium compound (T). The range is from 01 to 10 parts by weight, preferably from 0.1 to 8 parts by weight. If the amount of the titanium oxide sol is less than 0.01 part by weight, the effect of adding the titanium oxide sol such as the storage stability of the coating agent and the improvement of the corrosion resistance of the obtained titanium oxide film cannot be obtained. It is not preferable because the film forming property of the coating agent is inferior.
The titanium-containing aqueous liquid (A) may be further mixed with an aqueous solution of peroxotitanic acid obtained by mixing a hydrolyzable titanium compound (T) with aqueous hydrogen peroxide in the presence of a titanium oxide sol, if necessary, further at 80 ° C. or higher. Can be used as a dispersion liquid of titanium oxide fine particles having an average particle diameter of 10 nm or less by heat treatment or autoclave treatment at the temperature described above. The appearance of this dispersion is usually translucent.
If the temperature of the heat treatment or the autoclave treatment is lower than 80 ° C., crystallization of titanium oxide does not proceed sufficiently. The titanium oxide fine particles obtained by the above treatment have a particle size of 10 nm or less, preferably in the range of 1 nm to 6 nm. When the particle diameter is larger than 10 nm, the film-forming property is deteriorated, and cracks occur at a film thickness of 1 μm or more, which is not preferable.
When the titanium-containing aqueous liquid (A) is the aqueous liquid (A1), an amorphous titanium oxide film containing a small amount of hydroxyl groups is usually formed under the above-mentioned drying conditions. The amorphous titanium oxide film has an advantage that the gas barrier property is excellent. In the case of the titanium-containing aqueous liquid (A2), an anatase type titanium oxide film containing a small amount of a hydroxyl group is usually formed under the above drying conditions.
The phosphoric acid compound (B) in the coating composition I of the present invention has an action of improving the corrosion resistance of the obtained coating film. Examples of the compound (B) include phosphorous acid, strong phosphoric acid, triphosphoric acid, hypophosphorous acid, hypophosphoric acid, trimetaphosphoric acid, diphosphorous acid, diphosphoric acid, pyrophosphoric acid, and pyrophosphoric acid And monophosphoric acids such as metaphosphoric acid, metaphosphoric acid, and orthophosphoric acid; derivatives and salts of monophosphoric acids; condensed phosphoric acids such as tripolyphosphoric acid, tetraphosphoric acid, and hexaphosphoric acid; and derivatives and salts of condensed phosphoric acids. One or more of these compounds can be used. Examples of the alkali compound that forms the salt of the phosphoric acid compound include an organic or inorganic alkali compound containing lithium, sodium, potassium, ammonium and the like.
As the phosphoric acid compound (B), it is preferable to use a compound that is soluble in water.
As the phosphoric acid-based compound (B), use of sodium pyrophosphate, sodium tripolyphosphate, sodium tetraphosphate, metaphosphoric acid, ammonium metaphosphate, sodium hexametaphosphate, etc. can provide storage stability of the coating agent. It is preferable because it exhibits excellent effects such as corrosion resistance of the coating film.
The content ratio of the titanium-containing aqueous liquid (A) and the phosphoric acid compound (B) is preferably about 1 to 400 parts by weight with respect to 100 parts by weight of the solid content of the former. When the amount of the component (B) is less than 1 part by weight, the corrosion resistance and the like are reduced. On the other hand, when the amount of the component (B) is more than 400 parts by weight, the film-forming properties are poor and the corrosion resistance and the like are undesirably reduced. The content ratio of the phosphoric acid compound (B) is more preferably about 10 to 200 parts by weight with respect to 100 parts by weight of the titanium-containing aqueous liquid (A).
The coating agent I for forming a titanium oxide film of the present invention is produced by mixing a titanium-containing aqueous liquid (A) and a phosphoric acid compound (B) by a conventional method. In the coating composition I of the present invention, it is considered that the phosphate compound (B) forms a complex structure between the acid phosphate group ions bound to the compound (B) by coordinating with the titanium ions. Can be Such a complex structure is easily formed by simply mixing both components, and is formed, for example, by allowing the mixture to stand at room temperature (20 ° C.) for about 5 minutes to about 1 hour. When the mixture is heated, for example, by heating at about 30 to about 70 ° C. for about 1 to 30 minutes, a complex structure is formed.
The coating agent I for forming a titanium oxide film of the present invention is an aqueous liquid that is stable in a neutral or acidic region, and its pH is usually in the range of 1 to 7. Particularly, storage stability is good in an acidic region, and the pH is preferably in the range of 1 to 5. The coating composition I of the present invention may contain a hydrophilic solvent such as methanol, ethanol, isopropyl alcohol, ethylene glycol, and propylene glycol, if necessary. The coating composition I of the present invention can be diluted with water or a hydrophilic solvent, if necessary.
In the coating agent I for forming a titanium oxide film of the present invention, if necessary, in order to further improve the corrosion resistance of the obtained coating film, a titanium halide, a titanium halide salt, a zirconium halide, a zirconium halide salt, It can contain at least one halide selected from the group consisting of silicon halides and silicon halide salts.
Examples of the halogen constituting the halide include fluorine, chlorine, and iodine. As the halogen, fluorine is particularly preferable since it has excellent properties such as storage stability of a coating agent, corrosion resistance of a coating film, and moisture resistance. In addition, examples of a compound that forms a halide salt include sodium, potassium, lithium, and ammonium. Potassium and sodium are preferred as salts.
Examples of the halide include titanium halides such as titanium hydrofluoric acid, titanium halide salts such as potassium titanium fluoride and ammonium fluoride, zirconium halides such as zirconium hydrofluoric acid, and ammonium zirconium fluoride. And zirconium halide salts such as potassium zirconium fluoride, silicon halides such as hydrosilicofluoric acid, and silicon halide salts such as sodium silicofluoride, ammonium silicofluoride and potassium silicofluoride.
When the above-mentioned halide is contained in the coating composition I of the present invention, the content ratio is usually in the range of about 1 to 400 parts by weight, particularly preferably 10 to 400 parts by weight, based on 100 parts by weight of the solid content of the titanium-containing aqueous liquid (A). Preferably it is in the range of 200 parts by weight.
The coating composition I of the present invention may further contain, if necessary, a basic neutralizing agent such as ammonia, an organic basic compound, an alkali metal hydroxide, or an alkaline earth metal hydroxide. Preferred examples of the organic basic compound include ethanolamine and triethylamine, and examples of the preferred alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.
The coating composition I of the present invention may further contain various additives, if necessary. Examples of the additive include a thickener, a bactericide, a rust inhibitor, a titanium oxide sol, a titanium oxide powder, an extender pigment, a rust preventive pigment, a coloring pigment, a surfactant and the like. Examples of the rust preventive include tannic acid, phytic acid, benzotriazole and the like. Examples of the extender include mica, talc, silica, barium sulfate, clay and the like.
The coating agent II for forming a titanium oxide film of the present invention comprises an aqueous solution containing the titanium-containing aqueous liquid (A), a phosphoric acid compound and / or a titanium halide (B ′), and (C) an aqueous organic polymer compound. It is a coating agent.
As the titanium-containing aqueous liquid (A) in the coating composition II of the present invention, the same titanium-containing aqueous liquid as the coating liquid I of the present invention can be appropriately selected and used.
At least one compound selected from the group consisting of a phosphoric acid compound, a titanium halide, a titanium halide salt, a zirconium halide, a zirconium halide salt, a silicon halide and a silicon halide salt in the coating composition II of the present invention ( B ′) has an effect of improving the corrosion resistance of the obtained coating film.
Examples of the phosphoric acid compound in the compound (B ′) include phosphorous acid, strong phosphoric acid, triphosphoric acid, hypophosphorous acid, hypophosphoric acid, trimetaphosphoric acid, diphosphoric acid, diphosphoric acid, and pyrophosphoric acid. Monophosphoric acids such as phosphorous acid, pyrophosphoric acid, metaphosphoric acid, metaphosphoric acid, orthophosphoric acid, derivatives and salts of monophosphoric acids, condensed phosphoric acids such as tripolyphosphoric acid, tetraphosphoric acid, hexaphosphoric acid, and derivatives and salts of condensed phosphoric acids And the like. Examples of the alkali compound that forms the salt of the phosphoric acid compound include an organic or inorganic alkali compound containing lithium, sodium, potassium, ammonium and the like.
It is preferable to use a water-soluble compound as the above-mentioned phosphoric acid compound. Further, as the phosphoric acid-based compound, in particular, sodium pyrophosphate, sodium tripolyphosphate, sodium tetraphosphate, metaphosphoric acid, ammonium metaphosphate, sodium hexametaphosphate, etc. may be used, so that the storage stability of the coating agent and the resulting coating can be improved. It is preferable because it exhibits excellent effects such as corrosion resistance of the film.
Examples of the halogen constituting the titanium halide, the titanium halide salt, the zirconium halide, the zirconium halide salt, the silicon halide, and the silicon halide salt in the compound (B ′) include fluorine, chlorine, and iodine. . As the halogen, fluorine is particularly preferable since it has excellent properties such as storage stability of a coating agent, corrosion resistance of a coating film, and moisture resistance. In addition, examples of a compound that forms a halide salt include sodium, potassium, lithium, and ammonium. Potassium and sodium are preferred as salts.
Examples of the halide include titanium halides such as titanium hydrofluoric acid, titanium halide salts such as potassium titanium fluoride and ammonium fluoride, zirconium halides such as zirconium hydrofluoric acid, and ammonium zirconium fluoride. And zirconium halide salts such as potassium zirconium fluoride, silicon halides such as hydrosilicofluoric acid, and silicon halide salts such as sodium silicofluoride, ammonium silicofluoride and potassium silicofluoride.
In the coating agent II for forming a titanium oxide film of the present invention, the titanium-containing aqueous liquid (A) and at least one of the phosphoric acid compound and the titanium halide (B ′) form a complex structure between them. it is conceivable that. Such a complex structure is easily formed by simply mixing both components, and is formed, for example, by allowing the mixture to stand at room temperature (20 ° C.) for about 5 minutes to about 1 hour. When the mixture is heated, for example, by heating at about 30 to about 70 ° C. for about 1 to 30 minutes, a complex structure is formed.
The content ratio of the titanium-containing aqueous liquid (A) and the compound (B ′) in the coating composition II of the present invention is in the range of about 1 to 400 parts by weight, particularly 10 to 400 parts by weight, with respect to 100 parts by weight of the solid content of the former. Preferably it is in the range of 200 parts by weight.
The aqueous organic polymer compound (C) in the coating composition II for forming a titanium oxide film of the present invention has a pH of about 7 or less and does not cause aggregation, thickening, gelling, or the like when dissolved or dispersed in water. Any known materials can be used without limitation as long as they are in a stable state.
As the aqueous organic polymer compound (C), those having the form of an aqueous solution, an aqueous dispersion or an emulsion can be used. As a method for solubilizing, dispersing, or emulsifying the organic polymer compound in water, a known method can be used.
Specific examples of the aqueous organic polymer compound (C) include, for example, a functional group (for example, at least one of a hydroxyl group, a carboxyl group, an amino group, an imino group, a sulfide group, a phosphine group, etc.) Species), and those in which some or all of the functional groups of the compound are neutralized. In this case, the neutralization is performed when the aqueous organic polymer compound (C) is an acidic resin such as a carboxyl group-containing resin; an amine compound such as ethanolamine or triethylamine; ammonia water; lithium hydroxide, sodium hydroxide, or hydroxide. It is neutralized with an alkali metal hydroxide such as potassium or the like, and if it is a basic resin such as an amino group-containing resin, it is neutralized with a fatty acid such as acetic acid or lactic acid; a mineral acid such as phosphoric acid.
Examples of the aqueous organic polymer compound (C) include an epoxy resin, a phenol resin, an acrylic resin, a urethane resin, a polyvinyl alcohol resin, a polyoxyalkylene chain-containing resin, and an olefin-polymerizable unsaturated carboxylic acid. Copolymer resins, nylon resins, polyglycerin, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose and the like.
Among the above-mentioned aqueous organic polymer compounds (C), preferred are epoxy resins, phenol resins, acrylic resins, urethane resins, polyvinyl alcohol resins, polyoxyalkylene chain-containing resins, and olefin-polymerizable resins. And a saturated carboxylic acid copolymer resin.
In addition, according to the coating agent using a highly hydrophilic compound as the aqueous organic polymer compound (C), a film having both corrosion resistance and hydrophilicity can be formed, and a fin hydrophilizing agent for aluminum or aluminum alloy fins can be formed. It is suitable as.
As the epoxy resin, a cationic epoxy resin obtained by adding an amine to an epoxy resin; a modified epoxy resin such as an acryl-modified epoxy resin and a urethane-modified epoxy resin can be preferably used. Examples of the cationic epoxy resin include, for example, an adduct of an epoxy compound with a primary mono- or polyamine, a secondary mono- or polyamine, a mixed primary or secondary polyamine (see, for example, US Pat. No. 3,984,299); Adducts of an epoxy compound and a secondary mono- or polyamine having a ketiminated primary amino group (see, for example, US Pat. No. 4,017,438); a hydroxyl compound having a ketiminated primary amino group and an epoxy compound (See, for example, JP-A-59-43013).
The epoxy compound has a number average molecular weight of 400 to 4,000, particularly 800 to 2,000, and an epoxy equivalent of 190 to 2,000, especially 400 to 1,000. Is suitable. Such an epoxy compound can be obtained, for example, by reacting a polyphenol compound with epichlorohydrin. Examples of the polyphenol compound include bis (4-hydroxyphenyl) -2,2-propane, 4,4-dihydroxybenzophenone, bis (4-hydroxyphenyl) -1,1-ethane, and bis (4-hydroxyphenyl)- 1,1-isobutane, bis (4-hydroxy-tert-butylphenyl) -2,2-propane, bis (2-hydroxynaphthyl) methane, 1,5-dihydroxynaphthalene, bis (2,4-dihydroxyphenyl) methane And tetra (4-hydroxyphenyl) -1,1,2,2-ethane, 4,4-dihydroxydiphenylsulfone, phenol novolak, cresol novolak and the like.
As the above-mentioned phenolic resin, those obtained by making a polymer compound obtained by heating and adding and condensing a phenol component and formaldehydes in the presence of a reaction catalyst water-soluble can be suitably used. As the phenol component as a starting material, a bifunctional phenol compound, a trifunctional phenol compound, a phenol compound having four or more functional groups, or the like can be used. Examples of the bifunctional phenol compound include o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol, and 2,5-xylenol. Examples of tetrafunctional phenol compounds such as m-cresol, m-ethylphenol, 3,5-xylenol, and m-methoxyphenol include bisphenol A and bisphenol F. These phenol compounds can be used alone or in combination of two or more.
As the acrylic resin, for example, a homopolymer or copolymer of a monomer having a hydrophilic group such as a carboxyl group, an amino group, and a hydroxyl group, a monomer having a hydrophilic group and other copolymerizable monomers and And the like. These resins are obtained by emulsion polymerization, suspension polymerization or solution polymerization, and if necessary, neutralization and aqueous conversion. Further, the obtained resin may be further modified as necessary.
Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, crotonic acid, and itaconic acid.
Examples of the nitrogen-containing monomer include nitrogen-containing alkyl (meth) such as N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, and Nt-butylaminoethyl (meth) acrylate. Acrylate; acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N , N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide and other polymerizable amides; 2-vinylpyridine, 1-vinyl-2- Pyrrolidone, 4-vinyl Aromatic nitrogen-containing monomers such as lysine; and allylamine and the like.
Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2,3-dihydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and polyethylene glycol mono (meth) acrylate. Monoesters of polyhydric alcohols such as acrylates with acrylic acid or methacrylic acid; compounds obtained by ring-opening polymerization of ε-caprolactone with monoesters of the above polyhydric alcohols with acrylic acid or methacrylic acid.
Other copolymerizable monomers include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) Acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate And alkyl (meth) acrylates having 1 to 24 carbon atoms, such as styrene and vinyl acetate. These compounds can be used alone or in combination of two or more.
In addition, in this specification, "(meth) acrylate" means acrylate or methacrylate.
As the urethane resin, a polyurethane resin obtained from a polyol such as a polyester polyol or a polyether polyol and a diisocyanate may be a low molecular weight compound having two or more active hydrogens such as a diol or a diamine, if necessary. Those obtained by chain elongation in the presence of an extender and stably dispersed or dissolved in water can be suitably used. Examples of such urethane resins include, for example, JP-B-42-24192, JP-B-42-24194, JP-B-42-5118, JP-B-49-986, JP-B-49-33104, and JP-B-50-15027. And those known in JP-B-53-29175 and the like can be widely used.
As a method for stably dispersing or dissolving the polyurethane resin in water, for example, the following method can be used.
(1) A method of imparting hydrophilicity by introducing an ionic group such as a hydroxyl group, amino group, or carboxyl group into a side chain or a terminal of a polyurethane resin, and dispersing or dissolving in water by self-emulsification.
(2) A method of forcibly dispersing a completed polyurethane resin or a polyurethane resin having a terminal isocyanate group blocked with a blocking agent in water using an emulsifier and mechanical shearing force. Examples of the blocking agent include oximes, alcohols, phenols, mercaptans, amines, and sodium bisulfite.
(3) A method in which a polyurethane resin having a terminal isocyanate group is mixed with water, an emulsifier, and a chain extender, and dispersion and high molecular weight are simultaneously performed using mechanical shearing force.
(4) A method in which a polyurethane resin obtained by using a water-soluble polyol such as polyethylene glycol as a raw material polyol for a polyurethane resin is dispersed or dissolved in water.
The aqueous resin obtained by the method for dispersing or dissolving the polyurethane resin can be used alone or in combination of two or more.
Examples of the diisocyanate that can be used for synthesizing the polyurethane resin include aromatic, alicyclic, and aliphatic diisocyanates. Specifically, for example, hexamethylene diisocyanate, tetramethylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 1,3- (diisocyanato Methyl) cyclohexanone, 1,4- (diisocyanatomethyl) cyclohexanone, 4,4′-diisocyanatocyclohexanone, 4,4′-methylenebis (cyclohexyl isocyanate), isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,4 6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, 2,4-naphthalene diisocyanate, 3,3'-dimethyl-4,4'-bi E two-diisocyanate, 4,4'-biphenylene diisocyanate, and the like. Of these, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are particularly preferred.
Examples of commercially available polyurethane resins include, for example, “Hydran HW-330”, “Hydran HW-340”, “Hydran HW-350” (all manufactured by Dainippon Ink and Chemicals, Inc., trade names), “ Superflex 100 "," Superflex 150 "," Superflex F-3438D "(all manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade names) and the like.
The polyvinyl alcohol-based resin is preferably polyvinyl alcohol having a saponification degree of 87% or more, and particularly preferably so-called completely saponified polyvinyl alcohol having a saponification degree of 98% or more. Further, it is preferable that the number average molecular weight is in the range of 3,000 to 100,000.
As the polyoxyalkylene chain-containing resin, those having a polyoxyethylene chain or a polyoxypropylene chain can be suitably used, for example, polyethylene glycol, polypropylene glycol, and a polyoxyethylene chain and a polyoxypropylene chain in a block shape. Examples thereof include a bonded blocked polyoxyalkylene glycol.
Examples of the olefin-polymerizable unsaturated carboxylic acid copolymer resin include a copolymer of an olefin such as ethylene and propylene and a polymerizable unsaturated carboxylic acid such as (meth) acrylic acid and maleic acid, and the copolymer. At least one kind of water-dispersible resin or water-soluble resin selected from two kinds of resins obtained by adding a polymerizable unsaturated compound to an aqueous dispersion of the above (3), emulsion-polymerizing and then cross-linking within the particles can be suitably used.
The copolymer of an olefin and a polymerizable unsaturated carboxylic acid is a copolymer of one or more olefins and one or more polymerizable unsaturated carboxylic acids. In the copolymer, the content of the unsaturated carboxylic acid is suitably in the range of 3 to 60% by weight, preferably 5 to 40% by weight as the monomer content. The copolymer can be dispersed in water by neutralizing the acid groups in the copolymer with a basic substance.
To the aqueous dispersion of the above copolymer, emulsion polymerization is performed by adding a polymerizable unsaturated compound, and further as the polymerizable unsaturated compound in the crosslinked resin formed by intraparticle crosslinking, for example, the water dispersible or water soluble The vinyl monomers listed in the description of the acrylic resin and the like can be mentioned, and one or more kinds can be appropriately selected and used.
The content ratio of the aqueous organic polymer compound (C) is 10 to 2,000 parts by weight, particularly 100 to 1,000 parts by weight, based on 100 parts by weight of the solid content of the titanium-containing aqueous liquid (A). It is preferable in terms of the stability of the agent, the corrosion resistance of the obtained titanium oxide film, and the like.
The coating agent II for forming a titanium oxide film of the present invention can be prepared by mixing each essential component by a conventional method. The coating composition II of the present invention is an aqueous liquid that is stable in a neutral or acidic region, and its pH is usually in the range of 1 to 7. Particularly, storage stability is good in an acidic region, and the pH is preferably in the range of 1 to 5. The present coating composition II may contain a hydrophilic solvent such as methanol, ethanol, isopropyl alcohol, ethylene glycol, and propylene glycol, if necessary. The present coating composition II can be diluted with water or a hydrophilic solvent, if necessary.
The coating composition II of the present invention may further contain a basic neutralizer such as ammonia, an organic basic compound, an alkali metal hydroxide, or an alkaline earth metal hydroxide, if necessary. Examples of the organic basic compound include ethanolamine and triethylamine, and examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide, and potassium hydroxide.
The coating composition II of the present invention may further contain various additives as necessary. Examples of the additive include a thickener, a bactericide, a rust inhibitor, a titanium oxide sol, a titanium oxide powder, an extender pigment, a rust preventive pigment, a coloring pigment, a surfactant and the like. Examples of the rust preventive include tannic acid, phytic acid, benzotriazole and the like. Examples of the extender include mica, talc, silica, barium sulfate, clay and the like.
The coating agents I and II for forming a titanium oxide film of the present invention have excellent storage stability. Further, the coating agent can form a coating containing titanium oxide having good corrosion resistance, adhesion, workability and the like on a metal substrate.
Titanium oxide film forming method and metal substrate coated with titanium oxide film
The method for forming a titanium oxide film of the present invention is carried out by applying the coating agent I or II of the present invention to a metal substrate and drying the coating. Thus, a metal substrate covered with the titanium oxide film is obtained. This coated metal substrate can be used as it is as a rust-proof coated metal substrate.
The metal substrate to which the titanium oxide film forming method of the present invention is applied is not particularly limited as long as at least the surface is a metal. For example, a substrate whose surface is iron, aluminum, zinc, copper, tin, or an alloy containing any one of these metals can be given. In particular, it is preferable to use a steel plate substrate and an aluminum or aluminum alloy substrate.
Examples of the steel sheet substrate include a hot-dip galvanized steel sheet, an electro-galvanized steel sheet, an iron-zinc alloy-plated steel sheet, a nickel-zinc alloy-plated steel sheet, and an aluminum-zinc alloy-plated steel sheet. Further, as the aluminum-zinc alloy-plated steel sheet, for example, those sold under the trade names "Galvalume" and "Galphan" can be mentioned. Further, a zinc-based plated steel sheet which has been subjected to a chemical conversion treatment such as a chromate treatment, a zinc phosphate treatment, and a composite oxide film treatment can also be used as the steel plate substrate. Further, the steel sheet base material may be a steel sheet assembled.
The aluminum or aluminum alloy substrate is not particularly limited, but a typical example is a fin for a heat exchanger. The heat exchanger fins as the base material may be members before being assembled into a heat exchanger, or may be in a state assembled into a heat exchanger, and any known fins may be used. it can.
As a method for applying the coating agent I or II of the present invention to a metal substrate, for example, a known method such as dip coating, shower coating, spray coating, roll coating, and electrodeposition coating can be used. As for the drying condition of the coating agent, it is generally preferable to dry the coating material under heating conditions at which the maximum temperature of the material reaches about 60 to 250 ° C. for about 2 seconds to about 30 minutes.
Further, the dry film thickness of the coating agent is usually preferably about 0.001 to 10 μm, particularly preferably 0.1 to 3 μm. When the thickness is less than 0.001 μm, the performance such as corrosion resistance and water resistance is inferior. On the other hand, when the thickness exceeds 10 μm, the coating is cracked or the corrosion resistance decreases, which is not preferable.
Thus, according to the method for forming a titanium oxide film of the present invention, a titanium oxide film having good corrosion resistance, adhesion, workability, fingerprint resistance and the like can be formed on a metal substrate.
Further, the coating agent I or II of the present invention can be applied to a substrate other than the metal substrate and dried to form a titanium oxide film.
The substrate other than the metal substrate is not particularly limited. For example, polyvinyl chloride resin, polyethylene terephthalate, acrylic resin, silicone resin, polyester resin, fluorine resin, epoxy resin, polyethylene resin, nylon resin, butyral resin, cellulose resin, phenol resin, etc. Plastic bases composed of resins in which more than one kind of resin are combined; inorganic bases such as glass and cement; pulp bases such as paper and fiber; A substrate to which a primer has been applied can be mentioned.
As a method of coating the base material, for example, a known method such as dip coating, shower coating, spray coating, roll coating, and electrodeposition coating can be used. As for the drying condition of the coating agent, it is generally preferable that the coating material is dried under heating conditions at which the maximum temperature of the material reaches about 20 to 250 ° C. for about 2 seconds to about 30 minutes. Further, the dry film thickness of the coating agent is usually preferably about 0.001 to 10 μm.
On the substrate on which the titanium oxide film has been formed by the coating agent I or II of the present invention, an upper layer film can be formed, if necessary. The composition for forming the upper layer coating may be appropriately selected according to the purpose, and various coating compositions can be used. Examples of the coating composition include a lubricating coating forming composition, a highly corrosion resistant coating forming composition, a primer coating, and a colored top coating. A composition for forming a lubricating film, a composition for forming a highly corrosion-resistant film or a primer paint may be applied and dried, and then a colored top coat may be applied thereon.
The aluminum or aluminum alloy substrate coated with the coating agent I or II of the present invention has a coating excellent in corrosion resistance, hydrophilicity, adhesion, workability, etc., by performing light irradiation on this, Further, hydrophilicity can be improved.
If the coated substrate obtained by coating the coating agent of the present invention on an aluminum or aluminum alloy substrate is to be used as a fin for a heat exchanger, if necessary, a hydrophilic treatment may be further performed on the coated film. A coating can be formed.
The hydrophilized coating has a hydrophilic surface and a sufficient coating strength, and has good water resistance and good adhesion to the base coating. The formation of the above-mentioned hydrophilic treatment film can be suitably performed usually by applying and drying the hydrophilic treatment composition.
As the hydrophilic treatment composition, a composition containing a hydrophilic film-forming binder is preferable. Preferred hydrophilic film-forming binders include, for example, (1) an organic resin-based binder comprising a hydrophilic organic resin as a main component and optionally a crosslinking agent, and (2) a hydrophilic organic resin and colloidal silica. An organic resin / colloidal silica-based binder comprising a main component and optionally a cross-linking agent; (3) a water glass-based binder which is a mixture of a main component alkali silicate and an anionic or nonionic aqueous organic resin; Can be mentioned. Among these binders, an organic resin-based binder (1) and an organic resin-colloidal silica-based binder (2) are more preferable.
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described more specifically with reference to Production Examples, Examples and Comparative Examples. However, the present invention is not limited to the following examples. “Parts” and “%” described in each example are based on weight.
Preparation of titanium-containing aqueous liquid (A)
Production Example 1
10% ammonia water was added dropwise to an aqueous solution obtained by converting 5 cc of a 60% aqueous solution of titanium tetrachloride to 500 cc with distilled water to precipitate titanium hydroxide. After washing the precipitate with distilled water, 10 cc of a 30% solution of aqueous hydrogen peroxide was added and stirred to obtain 70 cc of a titanium-containing aqueous liquid (1) which is a translucent viscous liquid containing 2% solids and containing peroxotitanic acid.
Production Example 2
A mixture of 10 parts of tetra-iso-propoxytitanium and 10 parts of iso-propanol was added dropwise to a mixture of 10 parts of 30% aqueous hydrogen peroxide and 100 parts of deionized water at 20 ° C. over 1 hour with stirring. Thereafter, the mixture was aged at 25 ° C. for 2 hours to obtain a titanium-containing aqueous liquid (2) which is a yellow, transparent, slightly viscous peroxotitanic acid aqueous solution having a solid content of 2%.
Production Example 3
In Preparation Example 2, a titanium-containing aqueous liquid (3) having a solid content of 2% was obtained in the same manner as in Preparation Example 2, except that the same amount of tetra-n-butoxytitanium was used instead of tetra-iso-propoxytitanium. .
Production Example 4
In Preparation Example 2, a titanium-containing aqueous liquid having a solid content of 2% (4) was prepared in the same manner as in Preparation Example 2, except that the same amount of a trimer of tetraiso-propoxytitanium was used instead of tetraiso-propoxytitanium. ) Got.
Production Example 5
In Production Example 2, a titanium-containing material having a solid content of 2% was prepared in the same manner as in Production Example 2 except that hydrogen peroxide was added dropwise at 50 ° C. over 1 hour using a three-fold amount of hydrogen peroxide, followed by aging at 60 ° C. for 3 hours. An aqueous liquid (5) was obtained.
Production Example 6
The aqueous titanium-containing liquid obtained in Production Example 3 was further heated at 95 ° C. for 6 hours to obtain a titanium-containing aqueous liquid (6) having a solid content of 2%, which was a white-yellow translucent titanium oxide dispersion.
Production Example 7
A mixture of 10 parts of tetra-iso-propoxytitanium and 10 parts of iso-propanol was mixed with 5 parts of TKS-203 (trade name, manufactured by Teica Co., Ltd., aqueous sol of anatase-type titanium oxide fine particles having an average particle diameter of 6 nm). The mixture was added dropwise to a mixture of 10 parts of 30% hydrogen peroxide solution and 100 parts of deionized water with stirring at 10 ° C. for 1 hour. Thereafter, the mixture was aged at 10 ° C. for 24 hours to obtain a yellow transparent, slightly viscous titanium-containing aqueous liquid (7) having a solid content of 2%.
Example of coating agent I for forming titanium oxide film of the present invention
Example 1
50 parts of the titanium-containing aqueous liquid (1) obtained in Production Example 1 was mixed with 5 parts of 10% metaphosphoric acid and 45 parts of deionized water to obtain a coating composition for forming a titanium oxide film of the present invention.
Examples 2 to 16 and Comparative Examples 1 and 2
Based on the compositions shown in Table 1, a coating agent of the present invention and a coating agent for comparison were obtained in the same manner as in Example 1.

Performance test of coating agent I for forming titanium oxide film of the present invention
Using each coating agent obtained in Examples 1 to 16 and Comparative Examples 1 and 2, a coating treatment of a metal substrate was performed, and the corrosion resistance of the obtained coated substrate was examined.
(1) Coating treatment of aluminum plate
An aluminum plate (A1050) having a thickness of 0.1 mm is degreased and washed with an aqueous 2% concentration aqueous solution in which an alkali degreasing agent (trade name “Chem Cleaner 561B” manufactured by CB Chemical Co., Ltd.) is dissolved. , Each coating agent has a dry film weight of 0.2 g / m²And baked for 20 seconds so that the temperature of the material reached 100 ° C. to form a titanium oxide film.
(2) Corrosion resistance of coated plate
The above coated plates were measured according to the salt spray test method of JIS Z2371. The test time was set in four stages of 120 hours, 240 hours, 360 hours and 480 hours, and evaluated according to the following criteria.
a: No white rust or blistering is observed on the painted surface
b: White rust or swelling occurs a little,
c: White rust or blisters are remarkably generated.
Table 2 shows the test results.

(3) Steel plate coating
Electrogalvanized steel sheet with a thickness of 0.6 mm (coating weight 20 g / m on one side)²) Was degreased and washed with a 2% aqueous solution of an alkaline degreasing agent (trade name “Chem Cleaner 561B”, manufactured by CB Chemical Co., Ltd.). 0.0 g / m²Roll coating was performed so that the temperature reached 100 ° C. and baked for 20 seconds to form a titanium oxide film.
(4) Corrosion resistance of coated plate
The test coated plate in which the end face and the back face of each of the coated plates were sealed was measured according to the salt spray test method of JIS Z2371. The test time was set in three stages of 24 hours, 48 hours and 72 hours, and evaluated according to the following criteria.
a: No occurrence of white rust is observed.
b: The degree of white rust generation is less than 5% of the coating film area,
c: The degree of white rust generation is 5% or more and less than 10% of the coating film area,
d: The degree of white rust generation is 10% or more and less than 50% of the coating film area,
e: The degree of white rust generation is 50% or more of the coating film area.
Table 3 shows the test results.

(5) Coating treatment of steel sheet
Electrogalvanized steel sheet with a thickness of 0.6 mm (coating weight 20 g / m on one side)²) Was alkali-degreased, and then “Preparen Z” (trade name, manufactured by Nippon Parkerizing Co., Ltd.) was spray-coated to adjust the surface. Subsequently, "Palbond 3308" (trade name, aqueous solution of zinc phosphate, manufactured by Japan Parkerizing Co., Ltd.) was spray-coated, washed with water and dried to obtain a zinc phosphate-treated plated steel sheet. 1.5 g / m of zinc phosphate coating²And
On the surface of the plated steel sheet subjected to the zinc phosphate treatment, the above-mentioned respective coating agents were dried at a coating weight of 1.0 g / m.²And baked for 20 seconds at a material reaching temperature of 100 ° C. to form a titanium oxide film.
(6) Corrosion resistance of coated plate
The test coated plate in which the end face and the back face of each of the coated plates were sealed was measured according to the salt spray test method of JIS Z2371. The test time was set in three stages of 24 hours, 48 hours and 72 hours, and evaluated according to the following criteria.
a: No occurrence of white rust is observed.
b: The degree of white rust generation is less than 5% of the coating film area,
c: The degree of white rust generation is 5% or more and less than 10% of the coating film area,
d: The degree of white rust generation is 10% or more and less than 50% of the coating film area,
e: The degree of white rust generation is 50% or more of the coating film area.
Table 4 shows the test results.

Preparation of aqueous organic polymer compound (C)
Production Example 8
180 parts of isopropyl alcohol was placed in a 1 L four-necked flask equipped with a thermometer, a stirrer, a cooler, and a dropping funnel. After the replacement with nitrogen, the temperature in the flask was adjusted to 85 ° C, and 140 parts of ethyl acrylate was added. A monomer mixture consisting of 68 parts of methyl methacrylate, 15 parts of styrene, 15 parts of Nn-butoxymethylacrylamide, 38 parts of 2-hydroxyethyl acrylate and 24 parts of acrylic acid was added to 2,2'-azobis (2,2) as a catalyst. It was added dropwise over 6 hours with 6 parts of 4-dimethylvaleronitrile). When the reaction was continued at the same temperature for 5 hours after the completion of the dropwise addition, a colorless and transparent resin solution having a polymerization rate of about 100%, a solid content of about 63%, and an acid value of about 67 mgKOH / g was obtained. 108 parts of dimethylaminoethanol was mixed with 500 parts of this resin solution, water was added, and the mixture was sufficiently stirred to obtain an aqueous acrylic resin dispersion (C1) having a solid content of 30%.
Production Example 9
In a reactor equipped with a stirrer, a reflux condenser, a thermometer, and a liquid dropping device, 1,880 g (0.5 mol) of “Epicoat 1009” (trade name, epoxy resin having a molecular weight of 3,750, manufactured by Shell Chemical Co., Ltd.) After adding 1,000 g of a mixed solvent of and methyl isobutyl ketone / xylene = 1/1 (weight ratio), the mixture was stirred and heated to dissolve uniformly. Thereafter, the temperature was cooled to 70 ° C., and 70 g of the di (n-propanol) amine collected in the liquid dropping device was dropped over 30 minutes. During this time, the reaction temperature was kept at 70 ° C. After completion of the dropwise addition, the mixture was kept at 120 ° C. for 2 hours to complete the reaction, thereby obtaining an amine-modified epoxy resin having a solid content of 66%. To 1,000 g of the obtained resin, 25 parts of 88% formic acid were mixed, water was added, and the mixture was sufficiently stirred to obtain an aqueous amine-modified epoxy resin dispersion (C2) having a solid content of 30%.
Example of coating agent II for forming titanium oxide film of the present invention
Example 17
50 parts of the titanium-containing aqueous liquid (1) obtained in Production Example 1, 5 parts of a 20% zirconium hydrofluoric acid, 10 parts of a 30% aqueous acrylic resin dispersion (C1) and 35 parts of deionized water were mixed. The coating agent for forming a titanium oxide film of the invention was obtained.
Examples 18 to 27 and Comparative Examples 3 to 5
Based on the compositions shown in Table 5, a coating agent of the present invention and a coating agent for comparison were obtained in the same manner as in Example 17.

In Table 5, "Saran Latex L-411" and "Kuraray RS Polymer RS-105" indicate the following.
Saran latex L-411: manufactured by Asahi Kasei Corporation, trade name, vinylidene chloride resin, solid content 50%.
Kuraray RS Polymer RS-105: Kuraray Co., Ltd., trade name, polyvinyl alcohol, solid content 10%.
Performance test of the coating agent II for forming a titanium oxide film of the present invention
Using each of the coating agents obtained in Examples 17 to 27 and Comparative Examples 3 to 5, a rust-preventive coating treatment was performed on the steel sheet substrate, and the coating film appearance, adhesion, and corrosion resistance of the obtained coated steel sheet were examined.
(1) Rust prevention coating treatment of steel plate base material
Various plated steel sheets having a thickness of 0.8 mm were used as the base material. The following six types of plated steel sheets were used.
(I) Electrogalvanized steel sheet: coating weight 20 g / m², This is called "EG"
(Ii) Hot-dip galvanized steel sheet: 60 g / m coating weight²This is called "HDG"
(Iii) Zinc-iron alloy plated steel sheet: Fe content in plating of 10%, plating adhesion amount of 60 g / m²This is called "Zn-Fe".
(Iv) Zinc-nickel alloy-plated steel sheet: Ni content in plating: 12%, coating weight: 30 g / m²This is called "Zn-Ni".
(V) Zinc-aluminum alloy plated steel sheet: Al content in plating: 12%, coating weight: 150 g / m²This is referred to as “Zn-12% Al”
(Vi) Zinc-aluminum alloy plated steel sheet: 55% Al content during plating, 250 g / m coating weight²This is referred to as “Zn-55% Al”.
The surface of each of the plated steel sheets is degreased by spraying an aqueous solution having a concentration of 2% in which an alkali degreasing agent (trade name “Chem Cleaner 561B” manufactured by CB Chemical Co., Ltd.) is dissolved at a liquid temperature of 65 ° C. for 20 seconds. And hot water of 60 ° C. for 20 seconds to wash. Each of the coating agents is applied to the degreased plated steel sheet with a dry film weight of 0.5 g / m.²And spray dried at 250 ° C. for 15 seconds (attainment temperature of the material is 100 ° C.) to form a rust preventive film, thereby obtaining a coated steel sheet.
(2) Performance test of coated steel sheet
Each coated steel sheet obtained above was tested for coating film appearance, adhesion, and corrosion resistance based on the following test methods.
Test method
Coating appearance: The uniformity of the coating was visually evaluated based on the following criteria.
a: uniform appearance without unevenness
b: unevenness is partially present,
c: Unevenness is present on the entire surface.
Adhesion: The cross-cut tape method (1 mm gap) described in 8.5.2 of JIS K5400 was applied to the coating, and the adhesion was evaluated according to the following criteria.
a: No peeling of the coating was observed at all.
b: Peeling of the coating is observed, but the peeled area is less than 5%,
c: peeling area is 5% or more and less than 20%,
d: peeling area is 20% or more and less than 50%,
e: The peeled area is 50% or more.
Corrosion resistance: The end face and the back face of the coated steel sheet were sealed, and a salt spray test specified in JIS Z2371 was performed in three stages of 24 hours, 48 hours and 72 hours, and the corrosion resistance was evaluated according to the following criteria.
a: No white rust and blistering are observed on the coated surface,
b: The degree of white rust or blister generation is less than 10% of the coating area,
c: The degree of white rust or blister occurrence is 10% or more and less than 30% of the coating film area,
d: the degree of white rust or blister generation is 30% or more and less than 50% of the coating film area,
e: The degree of white rust or blister generation is 50% or more of the coating film area.
The test results are shown in Table 6.

Example of coating agent II for forming titanium oxide film of the present invention
Example 28
50 parts of the titanium-containing aqueous liquid (1) obtained in Production Example 1, 5 parts of 20% zirconium hydrofluoric acid, "AC10LP" (manufactured by Nippon Kayaku Co., Ltd., polyacrylic acid aqueous solution, weight average molecular weight 25,000, 30 parts of an acid value (779 mg KOH / g, solid content 10%) and 15 parts of deionized water were mixed to obtain a coating composition for forming a titanium oxide film of the present invention.
Examples 29 to 33 and Comparative Examples 6 to 7
Based on the composition shown in Table 7, a coating agent of the present invention and a coating agent for comparison were obtained in the same manner as in Example 28.

In Table 7, “AC10LP”, “Denkapovar K-05” and “PEG6000S” indicate the following.
AC10LP: manufactured by Nippon Kayaku Co., Ltd., trade name, aqueous solution of polyacrylic acid, weight average molecular weight 25,000, acid value 779 mgKOH / g, solid content 10%.
Denkapovar K-05: manufactured by Denki Kagaku Kogyo KK, trade name, polyvinyl alcohol, degree of saponification 99%, degree of polymerization 550, solid content 10%.
PEG6000S: manufactured by Sanyo Chemical Industry Co., Ltd., trade name, polyethylene glycol, average molecular weight 8,300, solid content 10%.
Performance test of the coating agent II for forming a titanium oxide film of the present invention
Using each of the coating agents obtained in Examples 28 to 33 and Comparative Examples 6 and 7, a rust-preventive coating treatment was performed on the aluminum substrate, and the coating film appearance, hydrophilicity, and corrosion resistance of the obtained coated aluminum plate were examined. .
(1) Rust prevention coating treatment of aluminum substrate
An aluminum plate (A1050) having a thickness of 0.1 mm is degreased and washed with an aqueous 2% concentration aqueous solution in which an alkali degreasing agent (trade name “Chem Cleaner 561B” manufactured by CB Chemical Co., Ltd.) is dissolved. Then, the coated aluminum plate was immersed in each coating agent at 30 ° C. for 30 seconds so as to have a dry film thickness of 5 μm and baked at 160 ° C. for 10 minutes to form a rust-preventive film, thereby obtaining a coated aluminum plate.
(2) Performance test of test coated plate
For each of the coated aluminum plates, a coating film appearance, hydrophilicity, and corrosion resistance were tested based on the following test methods.
Coating appearance: The uniformity of the antirust coating was visually evaluated based on the following criteria.
a: uniform appearance without unevenness
b: unevenness is partially present,
c: Unevenness is present on the entire surface.
Hydrophilicity: Run coated aluminum plate under running tap water (flow rate is 1m²Immersion in 15 kg / hr) for 72 hours to evaluate the hydrophilicity by the water contact angle. For comparison, the water contact angle was also measured (initial hydrophilicity) for the initial test plate before performing this test. The water contact angle was determined by drying a coated aluminum plate at 80 ° C. for 5 minutes, then dropping 0.04 cc of deionized water on the coated surface of the coated aluminum plate with a syringe to form a water droplet, and forming a water droplet contact angle. It was measured by "Contact Tangle Meter DCAA Type" manufactured by Kagaku Co., Ltd. The greater the water contact angle, the greater the hydrophilicity.
Corrosion resistance: Each coated aluminum plate was measured according to the salt spray test method of JIS Z2371. The test time was in two stages of 120 hours and 240 hours, and the corrosion resistance was evaluated according to the following criteria.
a: No white rust and blistering are observed on the coated surface;
b: The degree of white rust or blister generation is less than 10% of the coating area,
c: The degree of white rust or blister occurrence is 10% or more and less than 30% of the coating film area,
d: the degree of white rust or blister generation is 30% or more and less than 50% of the coating film area,
e: The degree of white rust or blister generation is 50% or more of the coating film area.
Table 8 shows the test results.

According to the coating agent for forming a titanium oxide film, the method for forming a titanium oxide film, and the metal substrate coated with the titanium oxide film of the present invention, the following special effects can be obtained.
(1) The coating composition of the present invention has excellent storage stability. The reason is that the titanium-containing aqueous liquid (A) itself is stable, and the aqueous liquid (A) forms a stable complex with the phosphoric acid compound, titanium halide or the like (B) or (B ′). It is thought to be due to this.
(2) According to the method for forming a titanium oxide film using the coating agent for forming a titanium oxide film of the present invention, titanium oxide having excellent corrosion resistance, adhesion, durability, workability, hydrophilicity, etc. is formed on a metal substrate. Can be formed.
This coating is excellent in corrosion resistance and durability because it has excellent adhesion to a substrate, because it is a dense titanium oxide film, it has low oxygen permeability and water vapor permeability, a phosphoric acid compound, a titanium halide and the like ( It is considered that B) or (B ′) functions as an etching agent and a corrosion inhibitor for metals, and that phosphoric acid compounds, titanium halides and the like (B or B ′) are protected by titanium oxide. . Further, it is considered that this film is excellent in adhesion because the titanium oxide in the film contains a hydroxyl group.
(3) The coated metal substrate obtained by applying the titanium oxide film forming method of the present invention can be suitably used as it is as a rust-preventive coating substrate.
(4) According to the fin for a heat exchanger in which the coating agent of the present invention is applied to the surface of an aluminum or aluminum alloy base material to form a coating, water bridge formation between the fins due to condensed water generated during cooling can be prevented. . Therefore, corrosion of the aluminum or aluminum alloy fins can be prevented.

Claims (31)

(A) Obtained by mixing at least one titanium compound selected from a hydrolyzable titanium compound, a low-condensate of a hydrolyzable titanium compound, titanium hydroxide and a low-condensate of titanium hydroxide with hydrogen peroxide. Titanium-containing aqueous liquid, and
(B) A coating composition for forming a titanium oxide film, comprising a phosphoric acid compound. The coating agent according to claim 1, wherein the titanium-containing aqueous liquid (A) is an aqueous solution of peroxotitanic acid obtained by mixing a hydrolyzable titanium compound and / or a low-condensate thereof with a hydrogen peroxide solution. The hydrolyzable titanium compound has a general formula of Ti (OR) ₄ (1)
The coating agent according to claim 2, wherein the coating agent is a tetraalkoxytitanium represented by the formula (wherein, R is the same or different and represents an alkyl group having 1 to 5 carbon atoms). The low-condensation product of the hydrolyzable titanium compound has the general formula Ti (OR) ₄ (1)
(Wherein R is the same or different and represents an alkyl group having 1 to 5 carbon atoms). A compound having a degree of condensation of 2 to 30 obtained by subjecting tetraalkoxy titaniums to condensation reaction with each other. 3. The coating composition according to 2. The mixing ratio of the hydrolyzable titanium compound and / or a low-condensate thereof and the hydrogen peroxide solution is such that the former is 10 parts by weight and the latter is in the range of 0.1 to 100 parts by weight in terms of hydrogen peroxide. Item 6. The coating agent according to Item 2. The titanium-containing aqueous liquid (A) is an aqueous peroxotitanic acid solution obtained by mixing a hydrolyzable titanium compound and / or a low-condensate thereof with hydrogen peroxide in the presence of a titanium oxide sol. The coating agent according to the above. The coating agent according to claim 6, wherein the titanium oxide sol is an aqueous dispersion of anatase-type titanium oxide. The coating agent according to claim 6, wherein the amount of the titanium oxide sol used is 0.01 to 10 parts by weight in terms of solid content based on 1 part by weight of the hydrolyzable titanium compound and / or its low condensate. The coating according to claim 1, wherein the phosphoric acid compound (B) is at least one compound selected from the group consisting of monophosphoric acids, derivatives and salts of monophosphoric acids, condensed phosphoric acids, derivatives and salts of condensed phosphoric acids. Agent. The coating agent according to claim 1, wherein the content ratio of the titanium-containing aqueous liquid (A) and the phosphoric acid compound (B) is 1 to 400 parts by weight based on 100 parts by weight of the solid content of the former. The coating agent for forming a titanium oxide film according to claim 1, which is an aqueous liquid having a pH of 1 to 7. The coating according to claim 1, further comprising at least one halide selected from the group consisting of titanium halides, titanium halide salts, zirconium halides, zirconium halide salts, silicon halides, and silicon halide salts. Agent. (A) Obtained by mixing at least one titanium compound selected from a hydrolyzable titanium compound, a low-condensate of a hydrolyzable titanium compound, titanium hydroxide and a low-condensate of titanium hydroxide with hydrogen peroxide. Titanium-containing aqueous liquid,
(B ′) at least one compound selected from the group consisting of phosphoric acid compounds, titanium halides, titanium halide salts, zirconium halides, zirconium halide salts, silicon halides and silicon halide salts, and (C) A) a coating agent for forming a titanium oxide film, which comprises a stable aqueous organic polymer compound at a pH of 7 or less; The coating agent according to claim 13, wherein the titanium-containing aqueous liquid (A) is a peroxotitanic acid aqueous solution obtained by mixing a hydrolyzable titanium compound and / or a low condensate thereof with a hydrogen peroxide solution. The hydrolyzable titanium compound has a general formula of Ti (OR) ₄ (1)
The coating composition according to claim 14, wherein R is the same or different and represents an alkyl group having 1 to 5 carbon atoms. The low-condensation product of the hydrolyzable titanium compound has the general formula Ti (OR) ₄ (1)
(Wherein R is the same or different and represents an alkyl group having 1 to 5 carbon atoms). A compound having a degree of condensation of 2 to 30 obtained by subjecting tetraalkoxy titaniums to condensation reaction with each other. 15. The coating agent according to 14. The mixing ratio of the hydrolyzable titanium compound and / or the low-condensate thereof and the hydrogen peroxide solution is such that the former is 10 parts by weight and the latter is in the range of 0.1 to 100 parts by weight in terms of hydrogen peroxide. Item 14. The coating agent according to Item 14. The titanium-containing aqueous liquid (A) is a peroxotitanic acid aqueous solution obtained by mixing a hydrolyzable titanium compound and / or a low-condensate thereof with hydrogen peroxide in the presence of a titanium oxide sol. The coating agent according to the above. The coating composition according to claim 18, wherein the titanium oxide sol is an aqueous dispersion of anatase-type titanium oxide. The coating agent according to claim 18, wherein the amount of the titanium oxide sol used is 0.01 to 10 parts by weight in terms of solid content based on 1 part by weight of the hydrolyzable titanium compound and / or its low condensate. The phosphoric acid compound in the compound (B ′) is at least one compound selected from the group consisting of monophosphoric acids, derivatives and salts of monophosphoric acids, condensed phosphoric acids, derivatives and salts of condensed phosphoric acids. The coating agent according to the above. The coating agent according to claim 13, wherein the halogen constituting the titanium halide, the titanium halide salt, the zirconium halide, the zirconium halide salt, the silicon halide and the silicon halide salt in the compound (B ') is fluorine. . The coating agent according to claim 13, wherein the content ratio of the titanium-containing aqueous liquid (A) and the compound (B ') is 1 to 400 parts by weight based on 100 parts by weight of the solid content of the former. The aqueous organic polymer compound (C) is an epoxy resin, a phenol resin, an acrylic resin, a urethane resin, a polyvinyl alcohol resin, a polyoxyalkylene chain-containing resin, and an olefin-polymerizable unsaturated carboxylic acid copolymer resin. The coating agent according to claim 13, which is at least one resin selected from the group consisting of: The coating agent according to claim 13, wherein the content ratio of the aqueous organic polymer compound (C) is 10 to 2,000 parts by weight based on 100 parts by weight of the solid content of the titanium-containing aqueous liquid (A). The coating agent according to claim 13, which is an aqueous liquid having a pH of 1 to 7. 14. A method for forming a titanium oxide film, comprising applying the coating material for forming a titanium oxide film according to claim 1 or 13 to a metal substrate and drying. A coated metal substrate having a coating of the coating material for forming a titanium oxide film according to claim 1 formed on a surface of the metal substrate. The coated metal substrate according to claim 28, wherein the coating has a thickness of 0.001 to 10 µm. The coated metal substrate according to claim 28, wherein the metal substrate is a steel plate. The coated metal substrate according to claim 28, wherein the metal substrate is aluminum or an aluminum alloy.