JP3820165B2 - Metal surface treatment composition - Google Patents

Description

【００３７】
上記エポキシ基と反応する官能基としては、例えば、−ＮＨ−等を挙げることができる。
【００３８】
上記ケチミンは、上述した方法により得られるエポキシ当量の下限が１５０、上限が１０００のビスフェノールＡ型エポキシ樹脂及び／又はビスフェノールＦ型エポキシ樹脂に付加するものである。上記ケチミンを付加させた後、酸により中和することにより１級アミノ基が導入され、これにより、得られる可溶性エポキシ樹脂の酸溶液中での安定性が良好になる。
【００３９】
上記ケチミンとしては、例えば、モノケチミン、ジケチミン等を挙げることができる。
上記モノケチミンとしては特に限定されず、例えば、アミノエチルエタノールアミンとメチルイソブチルケトン（ＭＩＢＫ）とを反応させることにより得られるアミノエチルエタノールアミンＭＩＢＫブロック体（アミノエチルエタノールアミン封鎖体）等を挙げることができる。
【００４０】
上記ジケチミンとしては特に限定されず、例えば、ジエチレントリアミンとメチルイソブチルケトン（ＭＩＢＫ）とを反応させることにより得られるジエチレントリアミンＭＩＢＫブロック体（ジエチレントリアミン封鎖体）等を挙げることができる。
【００４１】
上記ケチミンとしては、モノケチミンにより得られる可溶性エポキシ樹脂よりもジケチミンにより得られる可溶性エポキシ樹脂の方が樹脂として析出するｐＨが高いことから、ジケチミンを用いてアミノ基を導入する方が好ましく、ジエチレントリアミンＭＩＢＫブロック体（ジエチレントリアミン封鎖体）がより好ましい。
【００４２】
上記ケチミンを添加して付加反応させる際において、反応温度は、５０〜１５０℃で行うことが好ましい。５０℃未満であると、反応速度が小さくなるおそれがあり、１５０℃を超えると、経済的でない。
【００４３】
上記ケチミンを添加して付加反応させる際において、反応時間は、１０分〜５時間であることが好ましい。１０分未満であると、エポキシ基とアミノ基との反応が完全に進行していないおそれがあり、５時間を超えると、経済的でない。
【００４４】
上記ケチミンの添加量は、エポキシ当量の下限が１５０、上限が１０００のビスフェノールＡ型エポキシ樹脂及び／又はビスフェノールＦ型エポキシ樹脂のエポキシ１当量に対して、アミン（ＭＩＢＫ等により封鎖されたアミンを除く）下限０．８当量、上限１．２当量となるような添加量であることが好ましい。０．８当量未満であると、酸への溶解性が低下するおそれがあり、１．２当量を超えても、経済的でないおそれがある。より好ましい下限は０．９当量、より好ましい上限は１．１当量であり、更に好ましくは１当量である。
【００４５】
上記ケチミンを添加して付加反応させる際において、反応を行う組成物中の固形分濃度が５０〜９０質量％であることが好ましい。固形分濃度の調整には、例えば、上述した反応に用いるプロピレングリコールモノメチルエーテル等の溶剤を添加することにより行うことが好ましい。
【００４６】
上記可溶性エポキシ樹脂は、上述した方法により得られるケチミンが付加されたビスフェノールＡ型エポキシ樹脂及び／又はビスフェノールＦ型エポキシ樹脂を、更に酸により中和して得られるものである。酸により中和することにより、−ＮＨ_２、−ＮＨ_３ ^＋を有するものとなり、得られる可溶性エポキシ樹脂を酸溶液中で安定に溶解させることができる。
【００４７】
上記酸により中和することにより可溶性エポキシ樹脂を得る方法としては、例えば、酸と水とを入れた容器を攪拌しながら、上述した方法により得られるケチミンを付加したエポキシ樹脂を容器内に滴下することにより行うことができ、これにより可溶性エポキシ樹脂を得ることができる。使用する水は、純水であることが好ましい。
【００４８】
上記酸としては、導入されているアミノ基を中和するものであれば特に限定されず、例えば、酢酸、硝酸等を挙げることができる。なかでも、樹脂の溶解性の点から、酢酸が好ましい。
【００４９】
上記酸と水とを入れた容器内にケチミンを付加したエポキシ樹脂を滴下することにより中和を行う際において、中和率が１０〜１００％となるように上記酸の量を調整することが好ましい。１０％未満であると、得られるエポキシ樹脂の酸への溶解性が低下するおそれがあり、１００％を超えると、経済的でない。なお、上記中和率とは、エポキシ樹脂に導入されたアミノ基が酸によって中和される割合を意味するものである。
【００５０】
上記酸と水とを入れた容器内にケチミンを付加したエポキシ樹脂を滴下することにより中和を行う際において、樹脂滴下後における組成物の固形分濃度が３０〜７０質量％となることが好ましい。
【００５１】
上述した方法により得られた可溶性エポキシ樹脂は、反応終了後の中和・水溶化した状態で保存しておくことが好ましい。これにより、本発明の金属表面処理用組成物に可溶性エポキシ樹脂を含有させる際に、水に溶解した状態で保存しているエポキシ樹脂溶液を添加することにより行うことができるため、効率的に金属表面処理用組成物を調製することができる。また、アミン化したエポキシ樹脂は粘度が高く扱いにくいため、酸で中和し水溶化した方が扱い易い。
【００５２】
上記可溶性エポキシ樹脂を上記金属表面処理用組成物の成分として添加する場合には、可溶性エポキシ樹脂や、上記水に溶解した状態で保存されているエポキシ樹脂溶液を水により希釈して用いることが好ましい。
【００５３】
上記希釈の際には、希釈後の可溶性エポキシ樹脂溶液において、固形分濃度が５〜２５％となるように希釈することが好ましい。水を添加して希釈する際には、容器内に徐々に添加することが好ましく、例えば、上記ケチミンを付加したエポキシ樹脂の滴下後において得られる組成物の固形分濃度が５０％である場合には、５０％から４０％、３０％、２０％、１０％となるように順次水を添加することが好ましい。なお、希釈する場合には、水を連続的に添加してもよく、水を断続的に添加してもよい。使用する水は、純水であることが好ましい。
【００５４】
上記可溶性エポキシ樹脂の固形分としての含有量は、上記金属表面処理用組成物において、質量基準で、好ましい下限が２０ｐｍ、好ましい上限が２０００ｐｐｍである。２０ｐｐｍ未満であると、得られる化成皮膜中において、適正な樹脂析出量が得られないおそれがあり、２０００ｐｐｍを超えると、効率的に化成皮膜が形成されないおそれがある。より好ましい下限は１００ｐｐｍ、より好ましい上限は１０００ｐｐｍである。
【００５５】
上記金属表面処理用組成物は、実質的にリン酸イオンを含有しないものである。実質的にリン酸イオンを含まないとは、リン酸イオンが化成処理剤中の成分として作用するほど含まれていないことを意味し、具体的には、本発明の金属表面処理用組成物において、質量基準で、１０ｐｐｍ未満であることを意味するものである。実質的にリン酸イオンを含む場合には、形成される皮膜中のジルコニウム及び／又はチタン含有量が少なくなり、耐食性及び耐磨耗性等の性能が低下するおそれがある。本発明の金属表面処理用組成物は、実質的にリン酸イオンを含まないことから、環境負荷の原因となるリンを実質的に使用することがなく、リン酸亜鉛処理剤を使用する場合に発生するリン酸鉄、リン酸亜鉛等のようなスラッジの発生量を抑制することができる。
【００５６】
上記金属表面処理用組成物は、ｐＨの下限が２．５、上限が４．５である。２．５未満であると、樹脂の付着量が充分でないために、得られる化成皮膜の性能に劣るおそれがあり、４．５を超えると、化成浴中で可溶性エポキシ樹脂が析出するおそれがある。好ましい下限は３．０、好ましい上限は４．０であり、より好ましい下限は３．３、より好ましい上限は３．７である。
【００５７】
上記金属表面処理用組成物におけるｐＨの調整は、硝酸、過塩素酸、硫酸、硝酸ナトリウム、水酸化アンモニウム、水酸化ナトリウム、アンモニア等の化成処理に悪影響を与えない酸又は塩基を用いて行うのが好ましい。例えば、硝酸とアンモニア、又は、硝酸と水酸化ナトリウムによって調整する方法等を挙げることができ、硝酸とアンモニアにより調整する方法が好ましい。硝酸、アンモニア、水酸化ナトリウムを処理剤中に含有させても、これらは皮膜形成成分ではないので、化成処理によって減少する成分であるジルコニウムイオン、チタニウムイオン、フッ素イオン、可溶性エポキシ樹脂を補給することによりｐＨを所望の範囲に維持することができる。
【００５８】
上記金属表面処理用組成物において、処理剤中に硝酸イオンを含有させることによってｐＨを調整する場合には、硝酸イオンの含有量は、質量基準で、好ましい下限が１００ｐｐｍ、好ましい上限が５０００ｐｐｍである。１００ｐｐｍ未満であると、処理剤のｐＨを２．５〜４．５に維持できず、良好な皮膜が形成されないおそれがあり、５０００ｐｐｍを超えると、効率的に皮膜が形成されないおそれがある。より好ましい下限は２００ｐｐｍ、より好ましい上限は３０００ｐｐｍである。
【００５９】
本発明の金属表面処理用組成物を適用することができる基材としては、例えば、鉄系基材、亜鉛系基材、アルミニウム系基材等を挙げることができる。
上記鉄系基材とは、基材の一部又は全部が鉄及び／又はその合金からなる基材、上記亜鉛系基材とは、基材の一部又は全部が亜鉛及び／又はその合金からなる基材、上記アルミニウム系基材とは、基材の一部又は全部がアルミニウム及び／又はその合金からなる基材を意味する。
【００６０】
上記鉄系基材としては、例えば、冷延鋼板、熱延鋼板等を挙げることができる。上記亜鉛系基材としては、例えば、亜鉛めっき鋼板、亜鉛−ニッケルめっき鋼板、亜鉛−鉄めっき鋼板、亜鉛−クロムめっき鋼板、亜鉛−アルミニウムめっき鋼板、亜鉛−チタンめっき鋼板、亜鉛−マグネシウムめっき鋼板、亜鉛−マンガンめっき鋼板等の亜鉛系の電気めっき、溶融めっき、蒸着めっき鋼板等の亜鉛又は亜鉛系合金めっき鋼板等を挙げることができる。
上記アルミニウム系基材としては、例えば、５０００番系アルミニウム合金、６０００番系アルミニウム合金等を挙げることができる。
【００６１】
本発明の金属表面処理用組成物は、鉄系基材のみ、亜鉛系基材のみ又はアルミニウム系基材のみを単独で化成処理することもできるし、これらの基材のうち２種類以上、例えば、鉄系基材と亜鉛系基材を同時に化成処理することもできるし、鉄系基材と亜鉛系基材とアルミニウム系基材とを同時に化成処理することもできる。これにより、例えば、冷延鋼板のような鉄系基材、亜鉛鋼板のような亜鉛系基材及び６０００番系アルミニウム合金のようなアルミニウム系基材を同時に有する自動車車体等の構造物を本発明の金属表面処理用組成物により同時に化成処理することができ、また、アルミホイール等の部品を化成処理することもできる。
【００６２】
本発明の金属表面処理用組成物で、鉄系基材、亜鉛系基材、アルミニウム系基材を化成処理する化成処理方法としては、脱脂処理、脱脂後水洗処理、化成処理及び化成後水洗処理からなる方法であることが好ましく、上記化成処理方法は、鉄系基材、亜鉛系基材及びアルミニウム基材のうちの１種又は２種以上に適用することができる。
【００６３】
上記脱脂処理は、基材表面に付着している油分や汚れを除去するために行われるものであり、無リン・無窒素脱脂洗浄液等の脱脂剤により、通常３０〜５５℃において数分間程度の浸漬処理がなされる。所望により、脱脂処理の前に、予備脱脂処理を行うこともできる。
上記脱脂後水洗処理は、脱脂処理後の脱脂剤を水洗するために、大量の水洗水によって１回又はそれ以上でスプレー処理により行われるものである。
【００６４】
上記化成処理は、本発明の金属表面処理用組成物で、基材を化成処理することにより、基材表面に化成皮膜を形成させ、耐食性や耐磨耗性を付与するものである。処理方法としては、浸漬法、スプレー法等を挙げることができる。
【００６５】
上記化成処理において、上記金属表面処理用組成物の温度は、好ましい下限は２０℃、好ましい上限は６０℃であり、より好ましい下限は４０℃、より好ましい上限は５０℃である。２０℃未満であると、反応性に劣り、形成される皮膜量が小さくなり、耐食性が低下するおそれがあり、６０℃を超えると、エネルギーのロスが大きくなるおそれがある。
【００６６】
上記化成処理において、上記金属表面処理用組成物の処理時間は、好ましい下限は３０秒、好ましい上限は５分であり、より好ましい下限は６０秒、より好ましい上限は１８０秒である。３０秒未満であると、形成される皮膜量が充分でなく、耐食性や耐磨耗性が低下するおそれがあり、５分を超えると、皮膜形成における効率が悪いおそれがある。
【００６７】
上記化成後水洗処理は、その後の電着塗装後の塗膜外観等に悪影響を及ぼさないようにするために、１回又はそれ以上により行われるものである。この場合、最終の水洗は、純水で行われることが適当である。この化成後水洗処理においては、スプレー水洗又は浸漬水洗のどちらでもよく、これらの方法を組み合わせて水洗することもできる。
上記化成後水洗処理の後は、公知の方法に従って、必要に応じて乾燥され、その後、電着塗装や粉体塗装を行うことができる。
【００６８】
本発明の金属表面処理用組成物で、鉄系基材、亜鉛系基材、アルミニウム系基材を化成処理する化成処理方法は、従来より実用化されているリン酸亜鉛化成処理剤を用いて処理する方法において、必要となっている表面調整処理を行わなくてもよいため、より効率的に基材の化成処理を行うことができる。
【００６９】
上記化成処理方法により形成される化成皮膜におけるジルコニウム及び／又はチタン金属量としては、好ましい下限は１５ｍｇ／ｍ^２、好ましい上限は６０ｍｇ／ｍ^２であり、より好ましい下限は２０ｍｇ／ｍ^２、より好ましい上限は３０ｍｇ／ｍ^２である。１５ｍｇ／ｍ^２未満であると、化成皮膜における金属量が小さいために、耐食性や密着性等の性能を確保することができないおそれがあり、６０ｍｇ／ｍ^２を超えても、耐食性や密着性等の性能が悪くなるおそれがある。なお、ジルコニウム及び／又はチタン金属量とは、化成皮膜中におけるジルコニウムとチタンとの合計の金属量を意味するものである。
【００７０】
上記化成処理方法により形成される化成皮膜における炭素皮膜量（有機炭素量）としては、好ましい下限は５ｍｇ／ｍ^２、好ましい上限は６０ｍｇ／ｍ^２であり、より好ましい下限は２０ｍｇ／ｍ^２、より好ましい上限は３０ｍｇ／ｍ^２である。１５ｍｇ／ｍ^２未満であると、炭素皮膜量が小さいために、耐食性や密着性等の性能を確保することができないおそれがあり、６０ｍｇ／ｍ^２を超えても、耐食性や密着性等の性能が悪くなるおそれがある。なお、上記ジルコニウム及び／又はチタン金属量は、例えば、蛍光Ｘ線分析装置により測定することができ、上記炭素皮膜量（有機炭素量）は、例えば、炭素・水分分析装置により測定することができる。
【００７１】
上記化成処理方法により形成される皮膜量は、上記化成処理において、処理時間を長くすることによって、及び／又は、処理温度を高くすることによって、基材への付着量を大きくすることができる。これにより、処理時間及び／又は処理温度を調整することによって所望の付着量を基材上に形成することができ、耐食性や密着性等の性能を向上させることができる。
【００７２】
本発明の金属表面処理用組成物は、ジルコニウムイオン及び／又はチタニウムイオンを特定量含有し、フッ素イオンをジルコニウムイオン及び／又はチタニウムイオンに対してモル比で特定値以上含有し、処理剤のｐＨを特定範囲とするものであることから、形成される化成皮膜がジルコニウム及び／又はチタンを含むものとなり、これにより、塗装後に得られる基材が耐食性や耐磨耗性等の性能を有するものとなる。上記金属表面処理用組成物は、可溶性エポキシ樹脂を含有するものであることから、形成される化成皮膜がエポキシ樹脂を含むものとなり、これにより、エポキシ樹脂を含有しない処理剤を用いる場合に比べて、得られる化成皮膜の基材に対する密着性がより優れたものとなる。また、上記金属表面処理用組成物は、実質的にリン酸イオンを含有しないものであり、重金属を必須成分とするものでないことから、従来から実用化されているリン酸亜鉛処理剤による化成処理に比べて、リン酸亜鉛やリン酸鉄等のスラッジ、環境負荷となるリンや重金属の量を減少させることができるものである。更に、上記金属表面処理用組成物は、リン酸亜鉛による化成処理で必要な表面調整処理を行わなくてもよいことから、より効率的に化成処理を行うことができる。
【００７３】
【実施例】
以下に本発明を実施例により更に具体的に説明する。ただし、本発明はこれら実施例に限定されるものではない。また実施例中、「部」は特に断りのない限り「質量部」を意味する。
【００７４】
製造例１
攪拌機、冷却機、温度制御装置、窒素導入管、滴下ロートを備えた反応容器に液状エポキシ樹脂ＤＥＲ−３３１（ダウケミカル社製ビスフェノールＡ型エポキシ樹脂）３８６質量部、ビスフェノールＡ１１４質量部、プロピレングリコールモノメチルエーテル５６質量部、２−エチル−４−メチルイミダゾール０．０６質量部を仕込んで固形分濃度９０質量％の組成物とし、この反応容器を窒素ガスでパージしながら、１４５℃に昇温した後、３時間保温してエポキシ当量５００、数平均分子量１０００のビスフェノールＡ型エポキシ樹脂組成物を合成した。得られたビスフェノールＡ型エポキシ樹脂組成物にプロピレングリコールモノメチルエーテルを６９質量部添加することにより固形分濃度８０質量％のビスフェノールＡ型エポキシ樹脂組成物とし、９０℃に冷却した。
【００７５】
次に、９０℃に冷却されたビスフェノールＡ型エポキシ樹脂組成物を６２５質量部（固形分として５００質量部）に、アミノエチルエタノールアミンＭＩＢＫブロック体（アミノエチルエタノールアミン封鎖体）、２３６質量部を添加し、エポキシ１当量に対してアミン（メチルイソブチルケトンによって封鎖されたアミンを除く）１当量となるように配合した。更に、固形分濃度７０質量％となるようにプロピレングリコールモノメチルエーテルを１１９質量部添加した後、組成物の温度を１１５℃に調整して１時間保温して反応させ、その後放置により１００℃に冷却して、モノケチミン（アミノエチルエタノールアミンＭＩＢＫブロック体）が付加したエポキシ樹脂を合成した。
【００７６】
次に、９０質量％の酢酸６６質量部と純水３２２質量部とを入れた容器をケミスターラーで攪拌しながら、得られたモノケチミン（アミノエチルエタノールアミンＭＩＢＫブロック体）が付加したエポキシ樹脂を９７０質量部滴下し、固形分濃度５０質量％、中和率５０％の樹脂組成物を合成し、更に純水を順次滴下することにより、固形分濃度１０質量％の可溶性エポキシ樹脂溶液１を調製した（−ＮＨ_２及び／又は−ＮＨ_３ ^＋約０．２モル／樹脂１００ｇ）。
【００７７】
製造例２
アミノエチルエタノールアミンＭＩＢＫブロック体（アミノエチルエタノールアミン封鎖体）の代わりに、ジエチレントリアミンＭＩＢＫブロック体（ジエチレントリアミン封鎖体）を用いた以外は、製造例１と同様にして可溶性エポキシ樹脂溶液２を調製した（−ＮＨ_２及び／又は−ＮＨ_３ ^＋約０．４モル／樹脂１００ｇ）。
【００７８】
製造例３
液状エポキシ樹脂ＤＥＲ−３３１（ダウケミカル社製ビスフェノールＡ型エポキシ樹脂）、ビスフェノールＡの代わりに、液状エポキシ樹脂ＤＥＲ−３５４（ダウケミカル社製ビスフェノールＦ型エポキシ樹脂）、ビスフェノールＦを用いた以外は、製造例２と同様にして可溶性エポキシ樹脂溶液３を調製した。
【００７９】
比較製造例１
アミノエチルエタノールアミンＭＩＢＫブロック体（アミノエチルエタノールアミン封鎖体）の代わりに、メチルエタノールアミンを用いた以外は、製造例１と同様にして比較樹脂溶液１を調製した。
【００８０】
比較製造例２
アミノエチルエタノールアミンＭＩＢＫブロック体（アミノエチルエタノールアミン封鎖体）の代わりに、ジエタノールアミンを用いた以外は、製造例１と同様にして比較樹脂溶液２を調製した。
【００８１】
実施例１
市販の冷延鋼板；ＳＰＣＣ−ＳＤ（日本テストパネル社製、７０ｍｍ×１５０ｍｍ×０．８ｍｍ）に、下記の条件で、塗装前処理、電着塗装を施した。
（１）塗装前処理
脱脂処理：２質量％「サーフクリーナーＥＣ９２」（日本ペイント社製脱脂剤）で４０℃、２分間浸漬処理した。
脱脂後水洗処理：水道水で３０秒間スプレー処理した。
化成処理：ジルコンフッ化水素酸、フッ化水素酸、硝酸を用いて、ジルコニウムイオン１００ｐｐｍ、フッ素イオン１２５ｐｐｍ、硝酸イオン１０００ｐｐｍとし、製造例１で得られた可溶性エポキシ樹脂溶液１を固形分として５００ｐｐｍを添加し、アンモニアを用いてｐＨを３又は４に調整した金属表面処理用組成物を調製した。調製した金属表面処理用組成物の浴温度を４０℃に調整した後、冷延鋼板（ＳＰＣＣ−ＳＤ）を１２０秒間浸漬処理した。
化成後水洗処理：水道水で３０秒間スプレー処理した。
純水水洗処理：純水による流水洗、３０秒間スプレー処理した。
乾燥処理：水洗処理後の冷延鋼板を電気乾燥炉において、８０℃で１０分間乾燥し、化成皮膜が形成された鋼板を得た。
（２）電着塗装
上記塗装前処理（１）を行って化成皮膜が形成された冷延鋼板を「パワーニクス１１０」（日本ペイント社製カチオン電着塗料）を用いて乾燥膜厚１０μｍになるように電着塗装し、水洗後、１７０℃で２０分間加熱して焼き付けを行い、電着塗膜が形成された鋼板を得た。
【００８２】
実施例２〜１２
冷延鋼板、可溶性エポキシ樹脂溶液１の代わりに、表１に示した鋼板、可溶性エポキシ樹脂溶液を用いた以外は、実施例１の塗装前処理工程（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００８３】
実施例１３
実施例１における金属表面処理用組成物の代わりに、チタンフッ化水素酸、フッ化水素酸、硝酸を用いて、チタニウムイオン１００ｐｐｍ、フッ素イオン２４０ｐｐｍ、硝酸イオン１０００ｐｐｍとし、製造例２で得られた可溶性エポキシ樹脂溶液２を固形分として５００ｐｐｍを添加し、アンモニアを用いてｐＨを３又は４に調整した金属表面処理用組成物を用いて化成処理した以外は、実施例１の塗装前工程（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された冷延鋼板を得た。
【００８４】
実施例１４〜１６
冷延鋼板の代わりに、表１に示した鋼板を用いた以外は、実施例１３の塗装前処理工程（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００８５】
比較例１
可溶性エポキシ樹脂溶液１の代わりに、比較製造例１で得られた比較樹脂溶液１を用いた以外は、実施例１の塗装前処理工程（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００８６】
比較例２〜８
冷延鋼板、可溶性エポキシ樹脂溶液１の代わりに、表１に示した鋼板、比較樹脂溶液を用いた以外は、実施例１の塗装前処理工程（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００８７】
比較例９
可溶性エポキシ樹脂溶液１を用いなかった以外は、実施例１の塗装前処理工程（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００８８】
比較例１０〜１２
表１に示した鋼板を用いた以外は、比較例９の塗装前工程（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００８９】
比較例１３
塗装前処理（１）において、脱脂後水洗処理の後、「サーフファイン５Ｎ−８Ｍ」（日本ペイント社製表面調整剤）を用いて、室温で３０秒間表面調整処理を行い、化成処理において、「サーフダインＳＤ−６３５０（日本ペイント社製リン酸亜鉛処理剤）」を用いて、温度３５℃で２分間浸漬処理した以外は、実施例１の塗装前処理（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された冷延鋼板を得た。
【００９０】
比較例１４〜１６
冷延鋼板の代わりに、表１に示した鋼板を用いた以外は、比較例９の塗装前処理（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００９１】
比較例１７
塗装前処理（１）において、脱脂処理及び脱脂後水洗処理のみ行い、更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００９２】
比較例１８〜２０
冷延鋼板の代わりに、表１に示した鋼板を用いた以外は、比較例１７と同様にして電着塗膜が形成された鋼板を得た。
【００９３】
比較例２１
ｐＨ３又は４に調整した代わりに、ｐＨ２に調整した以外は、実施例１と同様にして化成皮膜が形成された冷延鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された冷延鋼板を得た。
【００９４】
比較例２２〜２４
冷延鋼板の代わりに、表１に示した鋼板を用いた以外は、比較例２１の塗装前処理（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００９５】
比較例２５
ｐＨ３又は４に調整した代わりに、ｐＨ２に調整した以外は、実施例２と同様にして化成皮膜が形成された冷延鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された冷延鋼板を得た。
【００９６】
比較例２６〜２８
冷延鋼板の代わりに、表１に示した鋼板を用いた以外は、比較例２５の塗装前処理（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００９７】
比較例２９
ｐＨ３又は４に調整した代わりに、ｐＨ２に調整した以外は、実施例３と同様にして化成皮膜が形成された冷延鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された冷延鋼板を得た。
【００９８】
比較例３０〜３２
冷延鋼板の代わりに、表１に示した鋼板を用いた以外は、比較例２９の塗装前処理（１）と同様にして化成皮膜が形成された鋼板を得た。更に、実施例１の電着塗装（２）と同様にして電着塗膜が形成された鋼板を得た。
【００９９】
〔評価〕
実施例１〜１６、比較例１〜３２により得られた化成皮膜が形成された鋼板及び電着塗膜が形成された鋼板をそれぞれ下記に示した方法により、化成皮膜における金属量及び炭素皮膜量（ｍｇ／ｍ^２）、塩水浸漬試験における皮膜性能を評価し、結果を表１、２に示した。
【０１００】
金属量及び炭素皮膜量（ｍｇ／ｍ ^２ ）
実施例１〜１６及び比較例１〜１２、２１〜３２において、塗装前工程（１）を行った鋼板の化成皮膜のジルコニウム又はチタン金属量（ｍｇ／ｍ^２）を「ＸＲＦ１７００」（島津製作所社製蛍光Ｘ線分析装置）により測定し、炭素皮膜量（ｍｇ／ｍ^２）を「ＲＣ４１２」（ＬＥＣＯ社製炭素・水分分析装置）により測定した。
【０１０１】
塩水浸漬試験
実施例１〜１６及び比較例１〜３２において、塗装前工程（１）及び電着塗装（２）を行った鋼板に、素地まで達する縦平行カットを２本入れた後、５％ＮａＣｌ水溶液中において、５０℃で４８０時間浸漬した。その後、カット部に粘着テープを貼り付けた後、そのテープを剥離して、カット部からの両側の塗膜剥がれ幅（ｍｍ、最大）を測定した。
【０１０２】
なお、表１、２中における記載は、以下のものを示す。
ＳＰＣ鋼板；冷延鋼板「ＳＰＣＣ−ＳＤ（日本テストパネル社製）」
ＧＡ鋼板；亜鉛鋼板「合金化溶融亜鉛メッキ鋼板（目付量表裏４５／４５ｇ／ｍ^２、新日本製鐵社製）」
５０００系アルミ；５０００番系アルミニウム合金「５０３２（神戸製鋼所社製）」
６０００系アルミ；６０００番系アルミニウム合金「６Ｋ２１（神戸製鋼所社製）」
樹脂１；可溶性エポキシ樹脂溶液１
樹脂２；可溶性エポキシ樹脂溶液２
樹脂３；可溶性エポキシ樹脂溶液３
比較樹脂１；比較樹脂溶液１
比較樹脂２；比較樹脂溶液２
Ｚｒ量；化成皮膜中のジルコニウム金属量
Ｔｉ量；化成皮膜中のチタン金属量
炭素量；化成皮膜中の有機炭素量
【０１０３】
【表１】

【０１０４】
【表２】

【０１０５】
表１、２より、ジルコニウムイオンを含む処理剤を用いる場合において、冷延鋼板に関しては、実施例１〜３と比較例１、２、９とを比べると、実施例により得られる化成皮膜中の有機炭素量の方が多くなっており、これにより密着性が向上し、塩水浸漬試験による試験結果も良好なものとなっていた。亜鉛鋼板、５０００番系アルミニウム合金、６０００番系アルミニウム合金に関しても、実施例４〜１２と比較例３〜８及び１０〜１２とを比べると、実施例により得られる化成皮膜中の有機炭素量の方が多くなっており、塩水浸漬試験による試験結果も比較例に比べると向上が見られた。また、チタンイオンを含む場合（実施例１３〜１６）でも、ジルコニウムイオンを含む場合と同等の塩水試験結果が得られた。実施例では、リン酸亜鉛処理剤を用いる場合（比較例１３〜１６）と比べると、亜鉛鋼板、５０００番系アルミニウム合金、６０００番系アルミニウム合金に関して同等の塩水試験結果が得られ、また、脱脂処理及び脱脂後水洗処理のみの場合（比較例１７〜２０）よりも良好な結果が得られた。更に、比較例２１〜３２（ｐＨ２の場合）に関しては、特に冷延鋼板において、塩水試験結果が劣っていた。
【０１０６】
実施例１７
市販の「アルミダイキャストＡＣ−４Ｃ（切削処理）」（日本ルートサービス社製アルミ板、７０ｍｍ×１５０ｍｍ×８ｍｍ）に下記の条件で塗装前処理、粉体塗装を施した。
（１）アルミ板塗装前処理
化成処理を以下の方法で行った以外は、実施例１の塗装前処理（１）と同様にして化成皮膜が形成されたアルミ板を得た。
化成処理：ジルコンフッ化水素酸、フッ化水素酸、硝酸を用いて、ジルコニウムイオン１００ｐｐｍ、フッ素イオン１２５ｐｐｍ、硝酸イオン１０００ｐｐｍとし、製造例２で得られた可溶性エポキシ樹脂溶液２を固形分として５００ｐｐｍを添加し、アンモニアを用いてｐＨを４に調整した金属表面処理用組成物を調製した。調製した金属表面処理用組成物の浴温度を５０℃に調整した後、アルミ板（アルミダイキャストＡＣ−４Ｃ）を９０秒間浸漬処理した。
（２）アルミ板粉体塗装
上記アルミ板塗装前処理（１）を行って化成皮膜が形成されたアルミ板を「パウダックスＡ４００クリアー」（日本ペイント社製粉体塗料）を用いて乾燥膜厚１００μｍになるように静電塗装し、１６０℃で２０分間加熱して焼き付けを行い、粉体塗膜が形成されたアルミ板を得た。
【０１０７】
実施例１８
可溶性エポキシ樹脂溶液２の代わりに、可溶性エポキシ樹脂溶液３を用いた以外は、実施例１７のアルミ板塗装前処理工程（１）と同様にして化成皮膜が形成されたアルミ板を得た。更に、実施例１７の粉体塗装（２）と同様にして粉体塗膜が形成されたアルミ板を得た。
【０１０８】
比較例３３
可溶性エポキシ樹脂溶液２を用いなかった以外は、実施例１７のアルミ板塗装前処理工程（１）と同様にして化成皮膜が形成されたアルミ板を得た。更に、実施例１の粉体塗装（２）と同様にして粉体塗膜が形成されたアルミ板を得た。
【０１０９】
〔評価〕
実施例１７、１８、比較例３３により得られた化成皮膜が形成されたアルミ板、粉体塗膜が形成されたアルミ板をそれぞれ下記に示した方法により、化成皮膜における金属量及び炭素皮膜量（ｍｇ／ｍ^２）、耐水二次密着性を評価し、評価結果を表３に示した。
【０１１０】
金属量及び炭素皮膜量（ｍｇ／ｍ ^２ ）
上記アルミ板塗装前工程（１）を行ったアルミ板の化成皮膜のジルコニウム金属量（ｍｇ／ｍ^２）を「ＸＲＦ１７００」（島津製作所社製蛍光Ｘ線分析装置）により測定し、炭素皮膜量（ｍｇ／ｍ^２）を「ＲＣ４１２」（ＬＥＣＯ社製炭素・水分分析装置）により測定した。
【０１１１】
耐水二次密着性試験
上記アルミ板塗装前処理（１）及び上記アルミ板粉体塗装（２）を行ったアルミ板を４０℃の純水に２４０時間浸漬した後、鋭利なカッターで２ｍｍ間隔の碁盤目（１００個）を形成し、その面に粘着テープを貼り付けた後、そのテープを剥離して、アルミ板から剥がれた碁盤目の数を測定した。
【０１１２】
なお、表３中における記載は、以下のものを示す。
アルミ板；「アルミダイキャストＡＣ−４Ｃ」（日本ルートサービス社製）
樹脂２；可溶性エポキシ樹脂溶液２
樹脂３；可溶性エポキシ樹脂溶液３
Ｚｒ量；化成皮膜中のジルコニウム金属量
炭素量；化成皮膜中の有機炭素量
【０１１３】
【表３】

【０１１４】
表３より、実施例１７、１８により得られた化成皮膜が形成されたアルミ板は、皮膜中に有機炭素が含まれており、また、粉体塗膜が形成されたアルミ板は、耐水二次密着性試験において剥離が見られなかった。一方、比較例３３により得られたものは、全面にわたって剥離が見られ、可溶性エポキシ樹脂を処理剤に含有させることによりアルミ板への密着性が向上した。これにより、実施例１７、１８に用いられた金属表面処理用組成物は、例えば、アルミホイール等に好適に用いることができることが明らかとなった。
【０１１５】
【発明の効果】
本発明の金属表面処理用組成物は、上述した構成よりなるので、従来のリン酸亜鉛処理剤と同様に、自動車車体等に用いられている鉄系基材、亜鉛系基材、アルミニウム系基材に良好な化成皮膜を形成することができ、形成される化成皮膜は、耐食性や密着性に優れるものである。また、リン酸亜鉛処理剤に比べて、スラッジ、リン、窒素、重金属の量を減少させることができるものでもあり、更に、本発明の金属表面処理用組成物で、鉄系基材、亜鉛系基材、アルミニウム系基材を化成処理する場合には、リン酸亜鉛処理剤による化成処理で必要な表面調整処理を行わなくてもよいことから、より効率的に化成処理を行うことができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal surface treatment composition, more specifically, an iron-based substrate such as a cold-rolled steel plate, a zinc-based substrate such as a galvanized steel plate, and an aluminum-based substrate such as a No. 5000 series or No. 6000 series aluminum alloy. On the other hand, the present invention relates to a metal surface treatment composition that can be suitably applied.
[0002]
[Prior art]
From the viewpoints of strength and weight reduction, metal molded bodies such as automobile bodies and parts are generally iron-based substrates such as cold-rolled steel sheets, zinc-based substrates such as galvanized steel sheets, 5000 series and 6000 series. These metal molded bodies are usually subjected to a surface treatment in order to improve corrosion resistance and wear resistance.
[0003]
This surface treatment method generally includes a degreasing treatment for removing oil adhering to the surface, a water washing treatment after degreasing, and a surface conditioning treatment for satisfactorily forming a chemical conversion film in the chemical conversion treatment as a subsequent step. It consists of a series of pre-coating treatment steps of zinc phosphate chemical conversion treatment and post-chemical conversion water washing treatment. As a chemical conversion treatment method that can be applied to all molded bodies made of an iron-based substrate, a zinc-based substrate, and an aluminum-based substrate, a chemical conversion treatment method using a zinc phosphate treating agent has been put into practical use.
[0004]
However, in the chemical conversion treatment method using a zinc phosphate treatment agent, a heavy metal such as nickel or manganese is contained in the treatment agent in order to contain a large amount of phosphorus or nitrogen in the treatment agent or to improve the performance of the formed chemical conversion film. If it is contained in a large amount, it may cause an environmental load, or a sludge such as zinc phosphate or iron phosphate may be generated as a waste after treatment, or a surface conditioning treatment may be required.
[0005]
As a treatment agent other than zinc phosphate, in Japanese Patent Application Laid-Open No. 2000-282251, an aluminum base material that is subjected to chemical conversion treatment with an acidic film chemical conversion treatment agent containing zirconium ions, titanium ions, phosphate ions, and fluorine ions, or A coating method for an aluminum alloy substrate has been proposed, but the treatment agent used here has been put to practical use as an electrodeposition coating base for an aluminum-based substrate or an aluminum alloy substrate. When applied to an iron-based substrate or a zinc-based substrate such as a steel plate, it has a problem of poor adhesion.
[0006]
In addition, as a surface treatment method for automotive parts such as aluminum wheels made of an aluminum base material or an aluminum alloy base material, it is possible to make use of the luminosity of the material and to improve the adhesion and corrosion resistance of the film. In view of this, chromate treatment is still widely used today. However, the trend of environmental regulations in recent years has required non-chromium, and in order to meet such demands, various organic and inorganic composites have been proposed, which are particularly satisfactory in terms of adhesion. Thus, further improvement has been desired.
[0007]
Therefore, it can be suitably applied to all iron-based, zinc-based, and aluminum-based substrates, has low phosphorus, nitrogen, and heavy metal content, and suppresses the generation of sludge such as zinc phosphate and iron phosphate. However, it has been desired to develop a chemical conversion treatment agent that is excellent in the adhesion of the chemical conversion film obtained without the necessity of performing the surface conditioning treatment required in the chemical conversion treatment method by the zinc phosphate treatment.
[0008]
[Problems to be solved by the invention]
In view of the above situation, the present invention is suitable for iron-based substrates such as cold-rolled steel plates, zinc-based substrates such as galvanized steel plates, and aluminum-based substrates such as No. 5000 series aluminum alloys and No. 6000 series aluminum alloys. An object of the present invention is to provide a metal surface treatment composition that can be applied, has a low content of phosphorus, nitrogen, and heavy metals, suppresses the generation of sludge, and is excellent in adhesion of the resulting chemical conversion film.
[0009]
[Means for Solving the Problems]
The present invention is a metal surface treatment composition comprising zirconium ions and / or titanium ions, fluorine ions, and a soluble epoxy resin, wherein the content of the zirconium ions and / or the titanium ions is It is 20 to 500 ppm on the basis, and the content of the fluorine ion is 6 times or more in molar ratio with respect to the zirconium ion and / or the titanium ion. NH₂And / or -NH₃ ⁺Is at least 0.1 mol, substantially does not contain phosphate ions, and has a pH of 2.5 to 4.5.For iron-based substratesIt is a composition for metal surface treatment.
[0010]
The soluble epoxy resin is preferably obtained by adding ketimine to a bisphenol A type epoxy resin and / or bisphenol F type epoxy resin having an epoxy equivalent of 150 to 1000 and further neutralizing with an acid.
This invention is also a metal surface treatment method characterized by treating the metal surface which consists of an iron-type base material using the metal surface treatment composition mentioned above.
The present invention will be described in detail below.
[0011]
The metal surface treatment composition of the present invention means a composition for chemical conversion treatment of a metal steel plate or a metal formed body, and by performing chemical conversion treatment by immersion or the like using the metal surface treatment composition, The corrosion resistance of the steel sheet or the metal molded body can be improved. When a coating film is further formed on the substrate after the chemical conversion treatment, the adhesion of the formed coating film to the substrate can be improved.
[0012]
The metal surface treatment composition of the present invention contains zirconium ions and / or titanium ions.
The zirconium ion and / or the titanium ion is a chemical film-forming component in the metal surface treatment composition of the present invention, and the chemical resistance of the base material is formed by forming a chemical film containing these components on the base material. And wear resistance can be improved.
[0013]
The content of the zirconium ion and / or the titanium ion is, on a mass basis, a lower limit of 20 ppm and an upper limit of 500 ppm. If the amount is less than 20 ppm, the amount of the chemical conversion film formed on the substrate may be reduced, which may reduce the corrosion resistance and wear resistance. If the amount exceeds 500 ppm, the chemical conversion film may not be formed efficiently. There is. A preferred lower limit is 50 ppm and a preferred upper limit is 300 ppm. The content of the zirconium ions and / or the titanium ions means the total content of zirconium ions and titanium ions. In the metal surface treatment composition of the present invention, a preferred form is one containing zirconium ions as an essential component.
[0014]
The zirconium ion supply source is not particularly limited. For example, K₂ZrF₆Alkali metal fluorozirconates, such as (NH₄)₂ZrF₆Fluorozirconate such as H;₂ZrF₆Soluble fluorozirconates such as fluorozirconic acid such as zirconium fluoride; zirconium oxide and the like.
[0015]
The titanium ion supply source is not particularly limited. For example, alkali metal fluorotitanate, (NH₄)₂TiF₆Fluorotitanate such as H;₂TiF₆Soluble fluorozirconate such as fluorotitanate acid, etc .; titanium fluoride; titanium oxide and the like.
[0016]
The metal surface treatment composition of the present invention contains fluorine ions.
The said fluorine ion plays the role of the etching agent of a base material in the composition for metal surface treatments of this invention.
[0017]
Content of the said fluorine ion is 6 times or more by molar ratio with respect to the said zirconium ion and / or the said titanium ion. In the metal surface treatment composition of the present invention, it means that the number of moles of the fluorine ions is at least 6 times the total number of moles of the zirconium ions and the titanium ions. If it is less than 6 times, etching becomes insufficient, a uniform film cannot be formed, and the corrosion resistance after coating may be reduced.
[0018]
The fluorine ion supply source is not particularly limited, and examples thereof include hydrofluoric acid, hydrofluoric acid salt, and boron fluoride acid. When the zirconium ion or the titanium complex mentioned as the titanium ion supply source is used as the fluorine ion supply source, the amount of the fluorine ion generated is insufficient. It is preferable to use together.
[0019]
The metal surface treatment composition of the present invention contains a soluble epoxy resin.
The soluble epoxy resin means an epoxy resin that can be dissolved in a solution adjusted to pH 2.5. Since it is an epoxy resin that can be stably dissolved at pH 2.5, it is possible to prevent the epoxy resin from being deposited even in the metal surface treatment composition of the present invention, and preferably the metal surface It can be contained in the treatment composition. In the case of a resin that precipitates at a pH of less than 2.5, it may be precipitated in the metal surface treatment composition of the present invention. Moreover, it is preferable not to melt | dissolve in the solution exceeding pH4.5. If the resin is deposited in excess of 4.5, there is a possibility that a chemical conversion film containing an epoxy resin is not formed. More preferably, it is an epoxy resin that can be dissolved in a solution adjusted to pH 3.0.
[0020]
By containing the said soluble epoxy resin, the chemical conversion film containing an epoxy resin can be formed, and, thereby, the adhesiveness of the chemical conversion film to the metal base material can be improved. This is presumed that the adhesion of the chemical conversion film is improved by the adsorption of functional groups such as hydroxyl groups present in the epoxy resin in the chemical conversion film to the surface of the metal substrate.
[0021]
In the said chemical film, it is guessed that an epoxy resin is contained as a component in a chemical film, when an epoxy resin self-precipitates in the interface of a metal base material and a processing agent. That is, the components such as fluorine ions in the metal surface treatment composition increase the pH at the interface between the metal substrate and the treatment agent by etching the metal substrate, and are present in the soluble epoxy resin at the interface − NH₃ ⁺-NH₂It is speculated that the solubility of the soluble epoxy resin decreases due to the change to, and as a result, the epoxy resin self-deposits on the surface of the metal substrate, thereby forming a chemical conversion film containing the epoxy resin. The
[0022]
The soluble epoxy resin is -NH per 100 g of resin.₂And / or -NH₃ ⁺At least 0.1 mol. That is, in 100 g of the soluble epoxy resin in the present invention, -NH₂A functional group represented by -NH₃ ⁺It means that the functional groups represented by the formula have at least 0.1 mol in total. As a result, the epoxy resin becomes soluble in acid and can maintain a stable state in the above-described metal surface treatment composition, and the pH on the surface of the base material rises when chemical conversion treatment is performed on the metal base material. Is contained as a component in the formed chemical film, and as a result, adhesion to the substrate surface is improved. If the amount is less than 0.1 mol, the acid solubility may be reduced, and precipitation may occur in the treatment bath. The soluble epoxy resin is -NH per 100 g of resin.₂And / or -NH₃ ⁺Are preferably those having a lower limit of 0.1 mol and an upper limit of 1.33 mol. A more preferable lower limit is 0.3 mol, and a more preferable upper limit is 0.5 mol. A more preferred lower limit is 0.4 mol.
[0023]
The soluble epoxy resin is preferably obtained by adding ketimine to a bisphenol A type epoxy resin and / or bisphenol F type epoxy resin having an epoxy equivalent of 150 to 1000 and further neutralizing with an acid. That is, for example, the soluble epoxy resin is prepared by first preparing a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin having a lower limit of epoxy equivalent of 150 and an upper limit of 1000, and then adding ketimine to the prepared resin. The ketimine adduct was then prepared, and the obtained ketimine adduct was further neutralized with an acid to give —NH₂, -NH₃ ⁺What is obtained by introduce | transducing can be mentioned.
[0024]
When the lower limit of the epoxy equivalent is 150 and the upper limit is 1000, the soluble epoxy resin can be prevented from being precipitated in the treatment bath and can be stably present. If it is less than 150, it may not function as the soluble epoxy resin in the present invention. When it exceeds 1000, there exists a possibility that the solubility to an acid cannot be hold | maintained. The preferable lower limit is 200, the preferable upper limit is 800, the more preferable lower limit is 400, and the more preferable upper limit is 600.
[0025]
As a manufacturing method of the bisphenol A type epoxy resin and / or bisphenol F type epoxy resin whose lower limit of the said epoxy equivalent is 150 and whose upper limit is 1000, for example, epichlorohydrin and bisphenol A and / or bisphenol F are epoxy equivalents of 150-1000. It can manufacture by well-known methods, such as mix | blending so that it may become and may react. Moreover, the commercially available bisphenol A type epoxy resin and / or bisphenol F type epoxy resin whose epoxy equivalent is 150-1000 can also be used.
[0026]
As a method for producing a bisphenol A type epoxy resin and / or bisphenol F type epoxy resin having a lower limit of 150 epoxy equivalents and an upper limit of 1000, a commercially available epoxy resin and bisphenol A and / or bisphenol F may be used in an epoxy equivalent of 150. It can also be obtained by blending and reacting so as to be ˜1000.
[0027]
When the commercially available epoxy resin is reacted with the bisphenol A and / or the bisphenol F, it can be produced by using a solvent, a catalyst and the like in combination.
Examples of the solvent include propylene glycol monomethyl ether, methyl isobutyl ketone, and xylene. Of these, propylene glycol monomethyl ether is preferred.
[0028]
The content of the solvent is preferably such that the lower limit of the solid content concentration in the composition used for the reaction is 60% by mass and the upper limit is 98% by mass. If it is less than 60% by mass or exceeds 98% by mass, the progress of the reaction may be inhibited. A more preferable lower limit is 70% by mass, and a more preferable upper limit is 95% by mass.
[0029]
Examples of the catalyst include 2-ethyl-4-methylimidazole and N, N-dimethylbenzylamine. Of these, 2-ethyl-4-methylimidazole is preferable.
[0030]
The content of the catalyst is such that the preferable lower limit is 50 ppm and the preferable upper limit is 500 ppm with respect to 100% by mass of the solid content of the commercially available epoxy resin used for the reaction. If it is less than 50 ppm, the effect of addition may not be seen, and if it exceeds 500 ppm, it is not economical. A more preferred lower limit is 100 ppm, and a more preferred upper limit is 300 ppm.
[0031]
The reaction of the commercially available epoxy resin with the bisphenol A and / or the bisphenol F is preferably performed in an inert gas atmosphere such as nitrogen.
The reaction temperature in the reaction of the commercially available epoxy resin with the bisphenol A and / or the bisphenol F can be usually about 100 to 200 ° C. If it is less than 100 ° C, the reaction rate may be low, and if it exceeds 200 ° C, it is not economical.
[0032]
The reaction between the commercially available epoxy resin and the bisphenol A and / or the bisphenol F is terminated when the epoxy equivalent is 150 to 1000, and the normal reaction time is about 1 to 10 hours. It is. If it is less than 1 hour or exceeds 10 hours, the epoxy equivalent may be out of the range of 150 to 1000. In general, the reaction between the commercially available epoxy resin and the bisphenol A and / or the bisphenol F is preferably performed while examining the epoxy equivalent of the epoxy resin during the reaction.
[0033]
In the reaction of the commercially available epoxy resin with the bisphenol A and / or the bisphenol F, as a method for examining the epoxy equivalent during the reaction, for example, JIS-K7236 (epoxy equivalent test method for epoxy resin) can be mentioned. it can.
[0034]
The number average molecular weight of the resin obtained by the reaction of the commercially available epoxy resin with the bisphenol A and / or the bisphenol F has a preferable lower limit of 300, a preferable upper limit of 2000, a more preferable lower limit of 500, and a more preferable upper limit. 1500. If it is less than 300, it may not function as a soluble epoxy resin in the present invention. If it exceeds 2000, the acid solubility may not be maintained.
[0035]
The ketimine means a compound having at least one structure represented by the following formula (1) and having at least one functional group that reacts with an epoxy group.
[0036]
[Chemical 1]

[0037]
Examples of the functional group that reacts with the epoxy group include —NH—.
[0038]
The ketimine is added to a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin having a lower limit of 150 epoxy equivalents obtained by the above-described method and an upper limit of 1000. After the ketimine is added, the primary amino group is introduced by neutralizing with an acid, whereby the stability of the resulting soluble epoxy resin in an acid solution is improved.
[0039]
Examples of the ketimine include monoketimine and diketimine.
The monoketimine is not particularly limited, and examples thereof include an aminoethylethanolamine MIBK block (aminoethylethanolamine blockade) obtained by reacting aminoethylethanolamine and methyl isobutyl ketone (MIBK). it can.
[0040]
The diketimine is not particularly limited, and examples thereof include a diethylenetriamine MIBK block (diethylenetriamine blockade) obtained by reacting diethylenetriamine and methyl isobutyl ketone (MIBK).
[0041]
As the ketimine, a soluble epoxy resin obtained by diketimine has a higher pH as a resin than a soluble epoxy resin obtained by monoketimine. Therefore, it is preferable to introduce an amino group using diketimine, and diethylenetriamine MIBK block. The body (diethylenetriamine blockade) is more preferred.
[0042]
When addition reaction is performed by adding the ketimine, the reaction temperature is preferably 50 to 150 ° C. If it is less than 50 ° C, the reaction rate may be low, and if it exceeds 150 ° C, it is not economical.
[0043]
In the addition reaction by adding the ketimine, the reaction time is preferably 10 minutes to 5 hours. If it is less than 10 minutes, the reaction between the epoxy group and the amino group may not proceed completely, and if it exceeds 5 hours, it is not economical.
[0044]
The amount of ketimine added is an amine (excluding amine blocked with MIBK or the like) with respect to 1 equivalent of epoxy of bisphenol A type epoxy resin and / or bisphenol F type epoxy resin having a lower limit of epoxy equivalent of 150 and an upper limit of 1000. ) The addition amount is preferably such that the lower limit is 0.8 equivalent and the upper limit is 1.2 equivalent. If it is less than 0.8 equivalent, the acid solubility may be reduced, and if it exceeds 1.2 equivalent, it may not be economical. A more preferred lower limit is 0.9 equivalent, a more preferred upper limit is 1.1 equivalent, and even more preferably 1 equivalent.
[0045]
When addition reaction is performed by adding the ketimine, the solid content concentration in the composition for the reaction is preferably 50 to 90% by mass. The solid content concentration is preferably adjusted, for example, by adding a solvent such as propylene glycol monomethyl ether used in the above-described reaction.
[0046]
The soluble epoxy resin is obtained by further neutralizing with bisphenol A type epoxy resin and / or bisphenol F type epoxy resin to which ketimine obtained by the above-described method is added. -NH by neutralizing with acid₂, -NH₃ ⁺The soluble epoxy resin obtained can be stably dissolved in an acid solution.
[0047]
As a method for obtaining a soluble epoxy resin by neutralizing with the acid, for example, while stirring a container containing acid and water, an epoxy resin added with ketimine obtained by the above-described method is dropped into the container. In this way, a soluble epoxy resin can be obtained. The water used is preferably pure water.
[0048]
The acid is not particularly limited as long as it neutralizes the introduced amino group, and examples thereof include acetic acid and nitric acid. Of these, acetic acid is preferred from the viewpoint of the solubility of the resin.
[0049]
When neutralizing by dropping an epoxy resin added with ketimine into a container containing the acid and water, the amount of the acid may be adjusted so that the neutralization rate is 10 to 100%. preferable. If it is less than 10%, the solubility of the resulting epoxy resin in the acid may decrease, and if it exceeds 100%, it is not economical. In addition, the said neutralization rate means the ratio by which the amino group introduce | transduced into the epoxy resin is neutralized with an acid.
[0050]
When neutralization is performed by dropping an epoxy resin added with ketimine into a container containing the acid and water, the solid content concentration of the composition after the resin dropping is preferably 30 to 70% by mass. .
[0051]
The soluble epoxy resin obtained by the above-described method is preferably stored in a neutralized and water-soluble state after completion of the reaction. Thereby, when the soluble epoxy resin is contained in the metal surface treatment composition of the present invention, it can be performed by adding an epoxy resin solution stored in a state of being dissolved in water. A composition for surface treatment can be prepared. Moreover, since an aminated epoxy resin has a high viscosity and is difficult to handle, it is easier to handle it by neutralizing with an acid and making it water-soluble.
[0052]
When adding the soluble epoxy resin as a component of the metal surface treatment composition, it is preferable to use a soluble epoxy resin or an epoxy resin solution stored in a state of being dissolved in water diluted with water. .
[0053]
In the case of the dilution, it is preferable to dilute the diluted soluble epoxy resin solution so that the solid content concentration is 5 to 25%. When diluting by adding water, it is preferably added gradually into the container. For example, when the solid content concentration of the composition obtained after dropping the epoxy resin added with the ketimine is 50%. It is preferable to add water sequentially so that it becomes 50% to 40%, 30%, 20%, 10%. In addition, when diluting, water may be added continuously or water may be added intermittently. The water used is preferably pure water.
[0054]
In the metal surface treatment composition, the content of the soluble epoxy resin as a solid content is preferably 20 pm, and preferably 2000 ppm, based on mass. If it is less than 20 ppm, there is a possibility that an appropriate amount of resin deposition cannot be obtained in the resulting chemical film, and if it exceeds 2000 ppm, the chemical film may not be formed efficiently. A more preferred lower limit is 100 ppm, and a more preferred upper limit is 1000 ppm.
[0055]
The metal surface treatment composition is substantially free of phosphate ions. The phrase “substantially free of phosphate ions” means that phosphate ions are not included so much as to act as a component in the chemical conversion treatment agent. Specifically, in the metal surface treatment composition of the present invention, Means less than 10 ppm on a mass basis. When the phosphate ion is substantially contained, the content of zirconium and / or titanium in the formed film is reduced, and performance such as corrosion resistance and wear resistance may be deteriorated. Since the metal surface treatment composition of the present invention does not substantially contain phosphate ions, it does not substantially use phosphorus that causes environmental burdens, and a zinc phosphate treatment agent is used. The amount of sludge generated such as iron phosphate and zinc phosphate generated can be suppressed.
[0056]
The metal surface treatment composition has a pH lower limit of 2.5 and an upper limit of 4.5. If it is less than 2.5, the amount of the resin attached is not sufficient, so that the performance of the resulting chemical conversion film may be inferior. If it exceeds 4.5, a soluble epoxy resin may be precipitated in the chemical conversion bath. . The preferred lower limit is 3.0, the preferred upper limit is 4.0, the more preferred lower limit is 3.3, and the more preferred upper limit is 3.7.
[0057]
The pH of the metal surface treatment composition is adjusted using an acid or base that does not adversely affect the chemical conversion treatment such as nitric acid, perchloric acid, sulfuric acid, sodium nitrate, ammonium hydroxide, sodium hydroxide, and ammonia. Is preferred. For example, a method of adjusting with nitric acid and ammonia, or nitric acid and sodium hydroxide can be exemplified, and a method of adjusting with nitric acid and ammonia is preferable. Even if nitric acid, ammonia, or sodium hydroxide is included in the treatment agent, these are not film-forming components, so replenish zirconium ions, titanium ions, fluorine ions, and soluble epoxy resins, which are components that decrease by chemical conversion treatment. Can maintain the pH within a desired range.
[0058]
In the metal surface treatment composition, when the pH is adjusted by including nitrate ions in the treatment agent, the content of nitrate ions is preferably 100 ppm and the preferable upper limit is 5000 ppm on a mass basis. . If it is less than 100 ppm, the pH of the treatment agent cannot be maintained at 2.5 to 4.5, and a good film may not be formed. If it exceeds 5000 ppm, a film may not be formed efficiently. A more preferred lower limit is 200 ppm, and a more preferred upper limit is 3000 ppm.
[0059]
Examples of the substrate to which the metal surface treatment composition of the present invention can be applied include an iron-based substrate, a zinc-based substrate, and an aluminum-based substrate.
The iron-based substrate is a substrate in which a part or all of the substrate is made of iron and / or an alloy thereof, and the zinc-based substrate is a part or all of the substrate made of zinc and / or an alloy thereof. The base material and the aluminum-based base material mean a base material in which a part or all of the base material is made of aluminum and / or an alloy thereof.
[0060]
As said iron-type base material, a cold-rolled steel plate, a hot-rolled steel plate, etc. can be mentioned, for example. Examples of the zinc-based substrate include galvanized steel sheet, zinc-nickel plated steel sheet, zinc-iron plated steel sheet, zinc-chromium plated steel sheet, zinc-aluminum plated steel sheet, zinc-titanium plated steel sheet, zinc-magnesium plated steel sheet, Examples thereof include zinc-based electroplating such as zinc-manganese-plated steel plate, hot-dip plating, zinc-plated alloy-plated steel plate, etc.
As said aluminum-type base material, 5000 series aluminum alloy, 6000 series aluminum alloy etc. can be mentioned, for example.
[0061]
The metal surface treatment composition of the present invention can be subjected to chemical conversion treatment only on an iron-based substrate, only a zinc-based substrate or only an aluminum-based substrate, and two or more of these substrates, for example, The iron-based substrate and the zinc-based substrate can be simultaneously subjected to chemical conversion treatment, and the iron-based substrate, the zinc-based substrate, and the aluminum-based substrate can be simultaneously subjected to chemical conversion treatment. Thus, for example, a structure such as an automobile body having an iron-based substrate such as a cold-rolled steel plate, a zinc-based substrate such as a galvanized steel plate, and an aluminum-based substrate such as No. 6000 series aluminum alloy at the same time. The metal surface treatment composition can be simultaneously subjected to chemical conversion treatment, and components such as aluminum wheels can also be chemical conversion treated.
[0062]
In the composition for metal surface treatment of the present invention, as a chemical conversion treatment method for chemical conversion treatment of iron-based substrate, zinc-based substrate, aluminum-based substrate, degreasing treatment, post-degreasing water washing treatment, chemical conversion treatment and post-chemical conversion water washing treatment Preferably, the chemical conversion treatment method can be applied to one or more of iron-based substrates, zinc-based substrates, and aluminum substrates.
[0063]
The degreasing treatment is performed to remove oil and dirt adhering to the surface of the base material, and usually with a degreasing agent such as phosphorus-free and nitrogen-free degreasing cleaning liquid at about 30 to 55 ° C. for about several minutes. Immersion treatment is performed. If desired, a preliminary degreasing treatment can be performed before the degreasing treatment.
The post-degreasing rinsing treatment is performed by spraying once or more with a large amount of rinsing water in order to wash the degreaser after the degreasing treatment.
[0064]
The chemical conversion treatment is a metal surface treatment composition according to the present invention, and a chemical conversion treatment is performed on the substrate surface to form a chemical conversion film on the surface of the substrate, thereby imparting corrosion resistance and wear resistance. Examples of the treatment method include an immersion method and a spray method.
[0065]
In the chemical conversion treatment, a preferable lower limit of the metal surface treatment composition is 20 ° C., a preferable upper limit is 60 ° C., a more preferable lower limit is 40 ° C., and a more preferable upper limit is 50 ° C. If it is less than 20 ° C., the reactivity is inferior, the amount of the formed film is reduced, and the corrosion resistance may be reduced, and if it exceeds 60 ° C., energy loss may be increased.
[0066]
In the chemical conversion treatment, the treatment time of the metal surface treatment composition is preferably 30 seconds, a preferred upper limit is 5 minutes, a more preferred lower limit is 60 seconds, and a more preferred upper limit is 180 seconds. If it is less than 30 seconds, the amount of the formed film is not sufficient, and the corrosion resistance and wear resistance may be reduced. If it exceeds 5 minutes, the efficiency in forming the film may be poor.
[0067]
The post-chemical conversion water-washing treatment is performed once or more so as not to adversely affect the appearance of the coating film after the subsequent electrodeposition coating. In this case, it is appropriate that the final water washing is performed with pure water. In this post-chemical conversion water washing treatment, either spray water washing or immersion water washing may be used, and these methods may be combined for water washing.
After the post-chemical conversion water-washing treatment, it is dried as necessary according to a known method, and then electrodeposition coating or powder coating can be performed.
[0068]
The chemical conversion treatment method for chemical conversion treatment of an iron-based substrate, a zinc-based substrate, and an aluminum-based substrate with the metal surface treatment composition of the present invention uses a zinc phosphate chemical conversion treatment agent that has been practically used. In the method of processing, since it is not necessary to perform the necessary surface conditioning treatment, the base material can be subjected to chemical conversion treatment more efficiently.
[0069]
As the amount of zirconium and / or titanium metal in the chemical conversion film formed by the chemical conversion treatment method, a preferable lower limit is 15 mg / m.²The preferred upper limit is 60 mg / m²The more preferred lower limit is 20 mg / m²The more preferable upper limit is 30 mg / m.²It is. 15 mg / m²If the amount is less than 60 mg / m, the amount of metal in the chemical conversion film is small, so that performances such as corrosion resistance and adhesion cannot be secured.²Even if it exceeds, there exists a possibility that performance, such as corrosion resistance and adhesiveness, may worsen. The zirconium and / or titanium metal amount means the total metal amount of zirconium and titanium in the chemical conversion film.
[0070]
As a carbon film amount (organic carbon amount) in a chemical conversion film formed by the chemical conversion treatment method, a preferable lower limit is 5 mg / m.²The preferred upper limit is 60 mg / m²The more preferred lower limit is 20 mg / m²The more preferable upper limit is 30 mg / m.²It is. 15 mg / m²If the amount is less than 1, the amount of the carbon film is small, and therefore there is a possibility that performances such as corrosion resistance and adhesion cannot be secured, and 60 mg / m²Even if it exceeds, there exists a possibility that performance, such as corrosion resistance and adhesiveness, may worsen. The amount of zirconium and / or titanium metal can be measured, for example, with a fluorescent X-ray analyzer, and the amount of carbon film (organic carbon amount) can be measured, for example, with a carbon / water analyzer. .
[0071]
The amount of the film formed by the chemical conversion treatment method can be increased by increasing the treatment time and / or increasing the treatment temperature in the chemical conversion treatment. Thereby, by adjusting the treatment time and / or treatment temperature, a desired adhesion amount can be formed on the substrate, and performance such as corrosion resistance and adhesion can be improved.
[0072]
The metal surface treatment composition of the present invention contains a specific amount of zirconium ions and / or titanium ions, and contains fluorine ions in a molar ratio relative to zirconium ions and / or titanium ions in a molar ratio, and the pH of the treatment agent. Therefore, the formed chemical film contains zirconium and / or titanium, and thus the base material obtained after coating has performance such as corrosion resistance and wear resistance. Become. Since the metal surface treatment composition contains a soluble epoxy resin, the formed chemical film contains an epoxy resin, thereby comparing with a case where a treatment agent not containing an epoxy resin is used. The adhesion of the obtained chemical conversion film to the base material is more excellent. The metal surface treatment composition is substantially free of phosphate ions and does not contain heavy metal as an essential component. In comparison with this, the amount of sludge such as zinc phosphate and iron phosphate, and the amount of phosphorus and heavy metals that cause environmental loads can be reduced. Furthermore, since the said metal surface treatment composition does not need to perform the surface adjustment process required by the chemical conversion treatment with a zinc phosphate, it can perform a chemical conversion treatment more efficiently.
[0073]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” means “parts by mass” unless otherwise specified.
[0074]
Production Example 1
386 parts by mass of liquid epoxy resin DER-331 (bisphenol A type epoxy resin manufactured by Dow Chemical Co., Ltd.), 114 parts by mass of bisphenol A, propylene glycol monomethyl, in a reaction vessel equipped with a stirrer, a cooler, a temperature controller, a nitrogen introduction tube, and a dropping funnel After charging 56 parts by mass of ether and 0.06 parts by mass of 2-ethyl-4-methylimidazole to obtain a composition having a solid concentration of 90% by mass, the reactor was heated to 145 ° C. while being purged with nitrogen gas. A bisphenol A type epoxy resin composition having an epoxy equivalent of 500 and a number average molecular weight of 1000 was synthesized by incubating for 3 hours. 69 parts by mass of propylene glycol monomethyl ether was added to the obtained bisphenol A type epoxy resin composition to obtain a bisphenol A type epoxy resin composition having a solid content concentration of 80% by mass and cooled to 90 ° C.
[0075]
Next, 625 parts by mass of the bisphenol A type epoxy resin composition cooled to 90 ° C. (500 parts by mass as a solid content), aminoethylethanolamine MIBK block (aminoethylethanolamine blockade), 236 parts by mass It was added so that 1 equivalent of amine (excluding amine blocked with methyl isobutyl ketone) was equivalent to 1 equivalent of epoxy. Further, after adding 119 parts by mass of propylene glycol monomethyl ether so that the solid content concentration becomes 70% by mass, the temperature of the composition is adjusted to 115 ° C. and kept for 1 hour to react, and then cooled to 100 ° C. by standing. Then, an epoxy resin to which monoketimine (aminoethylethanolamine MIBK block) was added was synthesized.
[0076]
Next, while stirring a container containing 66 parts by mass of 90% by mass of acetic acid and 322 parts by mass of pure water with a chemistor, 970 was added to the epoxy resin added with the obtained monoketimine (aminoethylethanolamine MIBK block). A soluble epoxy resin solution 1 having a solid content concentration of 10% by mass was prepared by dropping part by mass, synthesizing a resin composition having a solid content concentration of 50% by mass and a neutralization rate of 50%, and further adding pure water successively. (-NH₂And / or -NH₃ ⁺About 0.2 mol / 100 g resin).
[0077]
Production Example 2
A soluble epoxy resin solution 2 was prepared in the same manner as in Production Example 1 except that diethylenetriamine MIBK block (diethylenetriamine blockade) was used instead of aminoethylethanolamine MIBK block (aminoethylethanolamine blockade) ( -NH₂And / or -NH₃ ⁺About 0.4 mol / 100 g resin).
[0078]
Production Example 3
Liquid epoxy resin DER-331 (Dow Chemical Co., bisphenol A type epoxy resin), in place of bisphenol A, except that liquid epoxy resin DER-354 (Dow Chemical Co., bisphenol F type epoxy resin) and bisphenol F were used, A soluble epoxy resin solution 3 was prepared in the same manner as in Production Example 2.
[0079]
Comparative production example 1
A comparative resin solution 1 was prepared in the same manner as in Production Example 1 except that methylethanolamine was used instead of the aminoethylethanolamine MIBK block (aminoethylethanolamine blockade).
[0080]
Comparative production example 2
Comparative resin solution 2 was prepared in the same manner as in Production Example 1 except that diethanolamine was used instead of aminoethylethanolamine MIBK block (aminoethylethanolamine blockade).
[0081]
Example 1
Commercially available cold-rolled steel sheet; SPCC-SD (manufactured by Nippon Test Panel Co., Ltd., 70 mm × 150 mm × 0.8 mm) was subjected to coating pretreatment and electrodeposition coating under the following conditions.
(1) Pre-painting treatment
Degreasing treatment: A 2 mass% “Surf Cleaner EC92” (Nippon Paint Co., Ltd. degreasing agent) was immersed at 40 ° C. for 2 minutes.
Washing with water after degreasing: spraying with tap water for 30 seconds.
Chemical conversion treatment: Zircon hydrofluoric acid, hydrofluoric acid, and nitric acid were used to make zirconium ions 100 ppm, fluorine ions 125 ppm, and nitrate ions 1000 ppm. Then, a metal surface treatment composition having a pH adjusted to 3 or 4 using ammonia was prepared. After adjusting the bath temperature of the prepared metal surface treatment composition to 40 ° C., a cold-rolled steel sheet (SPCC-SD) was subjected to immersion treatment for 120 seconds.
Water treatment after chemical conversion: sprayed with tap water for 30 seconds.
Pure water washing treatment: Washing with pure water and spraying for 30 seconds.
Drying treatment: The cold-rolled steel plate after the water washing treatment was dried at 80 ° C. for 10 minutes in an electric drying furnace to obtain a steel plate on which a chemical conversion film was formed.
(2) Electrodeposition coating
The cold-rolled steel sheet on which the chemical conversion film was formed by performing the above-mentioned pre-coating treatment (1) was electrodeposited using “Powernics 110” (Cation Electrodeposition Paint manufactured by Nippon Paint Co., Ltd.) to a dry film thickness of 10 μm After washing with water, baking was performed by heating at 170 ° C. for 20 minutes to obtain a steel sheet on which an electrodeposition coating film was formed.
[0082]
Examples 2-12
Instead of the cold-rolled steel sheet and the soluble epoxy resin solution 1, a chemical conversion film is formed in the same manner as in the coating pretreatment step (1) of Example 1 except that the steel sheet and the soluble epoxy resin solution shown in Table 1 were used. A steel plate was obtained. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0083]
Example 13
In place of the metal surface treatment composition in Example 1, titanium hydrofluoric acid, hydrofluoric acid, and nitric acid were used to make titanium ions 100 ppm, fluorine ions 240 ppm, and nitrate ions 1000 ppm, and the solubility obtained in Production Example 2 Pre-painting step (1) of Example 1 except that 500 ppm was added as a solid content of the epoxy resin solution 2 and chemical conversion treatment was performed using a metal surface treatment composition adjusted to pH 3 or 4 using ammonia. In the same manner as above, a steel sheet on which a chemical conversion film was formed was obtained. Furthermore, the cold-rolled steel sheet in which the electrodeposition coating film was formed was obtained similarly to the electrodeposition coating (2) of Example 1.
[0084]
Examples 14-16
A steel sheet on which a chemical conversion film was formed was obtained in the same manner as in the coating pretreatment step (1) of Example 13 except that the steel sheet shown in Table 1 was used instead of the cold-rolled steel sheet. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0085]
Comparative Example 1
Instead of the soluble epoxy resin solution 1, a steel sheet having a chemical conversion film formed thereon was formed in the same manner as in the coating pretreatment step (1) of Example 1 except that the comparative resin solution 1 obtained in Comparative Production Example 1 was used. Obtained. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0086]
Comparative Examples 2-8
Instead of the cold rolled steel sheet and the soluble epoxy resin solution 1, a chemical conversion film was formed in the same manner as the coating pretreatment step (1) in Example 1 except that the steel sheet and the comparative resin solution shown in Table 1 were used. A steel plate was obtained. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0087]
Comparative Example 9
A steel sheet on which a chemical conversion film was formed was obtained in the same manner as in the coating pretreatment step (1) of Example 1 except that the soluble epoxy resin solution 1 was not used. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0088]
Comparative Examples 10-12
A steel sheet on which a chemical conversion film was formed was obtained in the same manner as in the pre-painting step (1) of Comparative Example 9 except that the steel sheet shown in Table 1 was used. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0089]
Comparative Example 13
In the pre-coating treatment (1), after degreasing and washing with water, using “Surffine 5N-8M” (Nihon Paint Co., Ltd. surface conditioning agent), surface conditioning treatment is performed for 30 seconds at room temperature. A chemical conversion film was formed in the same manner as the coating pretreatment (1) in Example 1 except that Surfsurfine SD-6350 (Nippon Paint Co., Ltd., zinc phosphate treatment agent) was used for immersion for 2 minutes at a temperature of 35 ° C. A formed steel sheet was obtained. Furthermore, the cold-rolled steel sheet in which the electrodeposition coating film was formed was obtained similarly to the electrodeposition coating (2) of Example 1.
[0090]
Comparative Examples 14-16
A steel sheet on which a chemical conversion film was formed was obtained in the same manner as the pre-coating treatment (1) of Comparative Example 9 except that the steel sheet shown in Table 1 was used instead of the cold-rolled steel sheet. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0091]
Comparative Example 17
In the pre-coating treatment (1), only a degreasing treatment and a post-degreasing water washing treatment were performed, and a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0092]
Comparative Examples 18-20
A steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as in Comparative Example 17 except that the steel sheet shown in Table 1 was used instead of the cold-rolled steel sheet.
[0093]
Comparative Example 21
Instead of adjusting to pH 3 or 4, a cold-rolled steel sheet having a chemical conversion film formed was obtained in the same manner as in Example 1 except that the pH was adjusted to 2. Furthermore, the cold-rolled steel sheet in which the electrodeposition coating film was formed was obtained similarly to the electrodeposition coating (2) of Example 1.
[0094]
Comparative Examples 22-24
A steel sheet on which a chemical conversion film was formed was obtained in the same manner as the pre-coating treatment (1) of Comparative Example 21, except that the steel sheet shown in Table 1 was used instead of the cold-rolled steel sheet. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0095]
Comparative Example 25
Instead of adjusting to pH 3 or 4, a cold-rolled steel sheet on which a chemical conversion film was formed was obtained in the same manner as in Example 2 except that the pH was adjusted to 2. Furthermore, the cold-rolled steel sheet in which the electrodeposition coating film was formed was obtained similarly to the electrodeposition coating (2) of Example 1.
[0096]
Comparative Examples 26-28
A steel sheet on which a chemical conversion film was formed was obtained in the same manner as the coating pretreatment (1) of Comparative Example 25 except that the steel sheet shown in Table 1 was used instead of the cold-rolled steel sheet. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0097]
Comparative Example 29
Instead of adjusting to pH 3 or 4, a cold-rolled steel sheet with a chemical conversion film formed was obtained in the same manner as in Example 3 except that the pH was adjusted to 2. Furthermore, the cold-rolled steel sheet in which the electrodeposition coating film was formed was obtained similarly to the electrodeposition coating (2) of Example 1.
[0098]
Comparative Examples 30-32
A steel sheet on which a chemical conversion film was formed was obtained in the same manner as the coating pretreatment (1) of Comparative Example 29 except that the steel sheet shown in Table 1 was used instead of the cold-rolled steel sheet. Further, a steel sheet on which an electrodeposition coating film was formed was obtained in the same manner as the electrodeposition coating (2) of Example 1.
[0099]
[Evaluation]
The amount of metal and the amount of carbon film in the chemical conversion film were respectively measured by the methods shown below for the steel sheet on which the chemical conversion film obtained in Examples 1 to 16 and Comparative Examples 1 to 32 was formed and the steel sheet on which the electrodeposition film was formed. (Mg / m²), The film performance in the salt water immersion test was evaluated, and the results are shown in Tables 1 and 2.
[0100]
Amount of metal and carbon film (mg / m ² )
In Examples 1 to 16 and Comparative Examples 1 to 12 and 21 to 32, the amount of zirconium or titanium metal (mg / m) in the chemical conversion film of the steel sheet subjected to the pre-painting step (1)²) Was measured with “XRF1700” (fluorescence X-ray analyzer manufactured by Shimadzu Corporation), and the carbon coating amount (mg / m²) Was measured with “RC412” (carbon / moisture analyzer manufactured by LECO).
[0101]
Salt water immersion test
In Examples 1 to 16 and Comparative Examples 1 to 32, two longitudinally parallel cuts that reach the substrate were put in the steel plate subjected to the pre-painting step (1) and the electrodeposition coating (2), and then in a 5% NaCl aqueous solution. The sample was immersed for 480 hours at 50 ° C. Then, after sticking an adhesive tape to a cut part, the tape was peeled and the coating film peeling width (mm, maximum) of both sides from a cut part was measured.
[0102]
In addition, the description in Table 1, 2 shows the following.
SPC steel sheet; cold-rolled steel sheet "SPCC-SD (manufactured by Nippon Test Panel)"
GA steel sheet; galvanized steel sheet "alloyed hot-dip galvanized steel sheet (weight per surface 45/45 g / m², Manufactured by Nippon Steel Corporation)
5000 series aluminum; 5000 series aluminum alloy "5032 (manufactured by Kobe Steel)"
6000 series aluminum; 6000 series aluminum alloy "6K21 (manufactured by Kobe Steel)"
Resin 1; Soluble epoxy resin solution 1
Resin 2; Soluble epoxy resin solution 2
Resin 3; Soluble epoxy resin solution 3
Comparative resin 1; Comparative resin solution 1
Comparative resin 2; Comparative resin solution 2
Zr amount; zirconium metal amount in the conversion coating
Ti amount: Titanium metal amount in the conversion coating
Carbon content: Organic carbon content in the conversion coating
[0103]
[Table 1]

[0104]
[Table 2]

[0105]
From Tables 1 and 2, when using a treatment agent containing zirconium ions, the cold-rolled steel sheet was compared with Examples 1 to 3 and Comparative Examples 1, 2, and 9 in the chemical conversion film obtained by the Examples. The amount of organic carbon was larger, which improved the adhesion, and the test result by the salt water immersion test was also good. Regarding the galvanized steel sheet, No. 5000 series aluminum alloy, No. 6000 series aluminum alloy, when Examples 4 to 12 and Comparative Examples 3 to 8 and 10 to 12 are compared, the amount of organic carbon in the chemical conversion film obtained by the examples is The test results by the salt water immersion test were improved compared to the comparative example. Even when titanium ions were included (Examples 13 to 16), the same salt water test results as when zirconium ions were included were obtained. In an Example, compared with the case where a zinc-phosphate processing agent is used (Comparative Examples 13-16), the same salt water test result is obtained regarding a galvanized steel sheet, No. 5000 series aluminum alloy, No. 6000 series aluminum alloy, and degreasing Better results were obtained than in the case of only water treatment after treatment and degreasing (Comparative Examples 17 to 20). Furthermore, regarding Comparative Examples 21 to 32 (in the case of pH 2), the results of the salt water test were inferior particularly in cold-rolled steel sheets.
[0106]
Example 17
Commercially available “aluminum die cast AC-4C (cutting treatment)” (aluminum plate manufactured by Nippon Route Service Co., Ltd., 70 mm × 150 mm × 8 mm) was subjected to pre-coating treatment and powder coating under the following conditions.
(1) Aluminum plate pre-treatment
An aluminum plate on which a chemical conversion film was formed was obtained in the same manner as in the pre-coating treatment (1) of Example 1 except that the chemical conversion treatment was performed by the following method.
Chemical conversion treatment: Zircon hydrofluoric acid, hydrofluoric acid, and nitric acid were used to make zirconium ions 100 ppm, fluorine ions 125 ppm, and nitrate ions 1000 ppm. Then, a metal surface treatment composition having a pH adjusted to 4 using ammonia was prepared. After adjusting the bath temperature of the prepared metal surface treatment composition to 50 ° C., an aluminum plate (aluminum die-cast AC-4C) was immersed for 90 seconds.
(2) Aluminum plate powder coating
The aluminum plate with the chemical conversion film formed by the above aluminum plate coating pretreatment (1) is electrostatically coated with “Powaxx A400 Clear” (powder paint manufactured by Nippon Paint Co., Ltd.) so as to have a dry film thickness of 100 μm. Baking was performed by heating at 160 ° C. for 20 minutes to obtain an aluminum plate on which a powder coating film was formed.
[0107]
Example 18
An aluminum plate on which a chemical conversion film was formed was obtained in the same manner as in the aluminum plate coating pretreatment step (1) of Example 17 except that the soluble epoxy resin solution 3 was used instead of the soluble epoxy resin solution 2. Further, an aluminum plate on which a powder coating film was formed was obtained in the same manner as in powder coating (2) of Example 17.
[0108]
Comparative Example 33
An aluminum plate on which a chemical conversion film was formed was obtained in the same manner as in the aluminum plate coating pretreatment step (1) of Example 17 except that the soluble epoxy resin solution 2 was not used. Further, an aluminum plate on which a powder coating film was formed was obtained in the same manner as in the powder coating (2) of Example 1.
[0109]
[Evaluation]
The amount of metal and the amount of carbon film in the chemical conversion film were respectively measured for the aluminum plate on which the chemical conversion film obtained in Examples 17 and 18 and Comparative Example 33 was formed and the aluminum plate on which the powder coating film was formed. (Mg / m²), Water-resistant secondary adhesion was evaluated, and the evaluation results are shown in Table 3.
[0110]
Amount of metal and carbon film (mg / m ² )
Zirconium metal content (mg / m) of the chemical conversion coating on the aluminum plate subjected to the aluminum plate pre-coating step (1)²) Was measured with “XRF1700” (fluorescence X-ray analyzer manufactured by Shimadzu Corporation), and the carbon coating amount (mg / m²) Was measured with “RC412” (carbon / moisture analyzer manufactured by LECO).
[0111]
Water resistance secondary adhesion test
After immersing the aluminum plate subjected to the aluminum plate coating pretreatment (1) and the aluminum plate powder coating (2) in pure water at 40 ° C. for 240 hours, a sharp cutter (100) After sticking an adhesive tape on the surface, the tape was peeled off, and the number of grids peeled off from the aluminum plate was measured.
[0112]
In addition, the description in Table 3 shows the following.
Aluminum plate; "Aluminum die-cast AC-4C" (Nippon Route Service Co., Ltd.)
Resin 2; Soluble epoxy resin solution 2
Resin 3; Soluble epoxy resin solution 3
Zr amount; zirconium metal amount in the conversion coating
Carbon content: Organic carbon content in the conversion coating
[0113]
[Table 3]

[0114]
From Table 3, the aluminum plate on which the chemical conversion film obtained in Examples 17 and 18 is formed contains organic carbon, and the aluminum plate on which the powder coating film is formed is water resistant. No peeling was observed in the next adhesion test. On the other hand, peeling was seen over the entire surface obtained in Comparative Example 33, and adhesion to the aluminum plate was improved by incorporating a soluble epoxy resin in the treatment agent. Thereby, it was revealed that the metal surface treatment composition used in Examples 17 and 18 can be suitably used for, for example, an aluminum wheel.
[0115]
【The invention's effect】
Since the composition for metal surface treatment of the present invention has the above-described configuration, it is similar to the conventional zinc phosphate treating agent, such as an iron-based substrate, a zinc-based substrate, and an aluminum-based substrate that are used in automobile bodies. A good chemical film can be formed on the material, and the formed chemical film is excellent in corrosion resistance and adhesion. In addition, the amount of sludge, phosphorus, nitrogen, and heavy metals can be reduced as compared with the zinc phosphate treatment agent. Furthermore, in the metal surface treatment composition of the present invention, an iron-based substrate, a zinc-based material In the case of subjecting the base material and the aluminum-based base material to chemical conversion treatment, the chemical conversion treatment can be performed more efficiently because it is not necessary to carry out the surface adjustment treatment necessary for the chemical conversion treatment with the zinc phosphate treating agent.

Claims (3)

A composition for metal surface treatment comprising zirconium ions and / or titanium ions, fluorine ions, and a soluble epoxy resin, wherein the content of the zirconium ions and / or the titanium ions is 20 on a mass basis. ˜500 ppm, the fluorine ion content is 6 times or more in molar ratio with respect to the zirconium ion and / or the titanium ion, and the soluble epoxy resin contains —NH ₂ and / or 100 g of resin. Or a metal surface for an iron-based substrate , having at least 0.1 mol of —NH ₃ ⁺ , substantially free of phosphate ions, and having a pH of 2.5 to 4.5 Treatment composition. The iron-based group according to claim 1, wherein the soluble epoxy resin is obtained by adding ketimine to a bisphenol A type epoxy resin and / or a bisphenol F type epoxy resin having an epoxy equivalent of 150 to 1000, and further neutralizing with an acid. material for the metal surface treatment composition. A metal surface treatment method comprising treating a metal surface comprising an iron-based substrate using the metal surface treatment composition for an iron-based substrate according to claim 1.