JP2004285378A

JP2004285378A - Rust resistant steel sheet for laminate vessel

Info

Publication number: JP2004285378A
Application number: JP2003076689A
Authority: JP
Inventors: Shigeru Hirano; 茂平野; Hiroichi Yokoya; 博一横矢
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 2003-03-20
Filing date: 2003-03-20
Publication date: 2004-10-14
Anticipated expiration: 2023-03-20
Also published as: JP3909030B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-treated steel sheet superior in, particularly, can-manufacturing workabilities such as drawing ironing workability, seam weldability, film adhesiveness, corrosion resistance and rust resistance, as a material for a laminate vessel. <P>SOLUTION: The rust resistant steel sheet for the laminate vessel has a surface treatment layer containing one or more of Sn, Ni, Fe, Cr and hydrated Cr oxide on at least one surface of a steel sheet, and has an aluminum phosphate compound layer of 0.01 to 500 mg/m<SP>2</SP>in terms of P thereon; or alternatively has the surface treatment layer containing one or more of Sn, Ni, Fe, Cr and hydrated Cr oxide on at least one surface of the steel sheet, and has an organic coating layer of 0.1 to 100 mg/m<SP>2</SP>in terms of C thereon, which contains an phosphoric acid aluminum compound of 0.001 to 50 mg/m<SP>2</SP>in terms of P. Thus manufactured surface-treated steel sheet provides the steel sheet for the laminate vessel, which has superior formability, weldability, film adhesiveness, corrosion resistance and rust resistance. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、製缶加工用素材として、絞りしごき加工、溶接性、耐食性、フィルム密着性に優れたラミネート容器用鋼板に関するものである。
【０００２】
【従来の技術】
飲料や食品に用いられる金属容器は、２ピース缶と３ピース缶に大別される。ＤＩ缶に代表される２ピース缶は、絞りしごき加工が行われた後、缶内面側に塗装が、缶外面側には塗装及び印刷が行われる。３ピース缶は、缶内面に相当する面に塗装が、缶外面側に相当する面に印刷が行われた後、缶胴部の溶接が行われる。何れの缶種においても、製缶前後に塗装工程が不可欠な工程である。塗装には、溶剤系もしくは水系の塗料が使用され、その後、焼付けが行われるが、この塗装工程において、塗料に起因する廃棄物（廃溶剤等）が産業廃棄物として排出され、排ガス（主に炭酸ガス）が大気に放出されている。近年、地球環境保全を目的とし、これら産業廃棄物や排ガスを低減しようとする取組みが行われている。この中で、塗装に代わるものとしてフィルムをラミネートする技術が注目され、急速に広まってきた。
【０００３】
これまでに、２ピース缶においては、フィルムをラミネートし製缶する缶の製造方法やこれに関連する発明が多数提供されている。例えば、特開昭６０−１７０５３２号公報（特許文献１）、特開平３−３２８３５号公報（特許文献２）、特開平２−２６３５２３号公報（特許文献３）および特開昭６０−１６８６４３号公報（特許文献４）が挙げられる。
また、３ピース缶においては、特開平３−２３６９５４号公報（特許文献５）、特開平５−１１１９７９号公報（特許文献６）および特開平５−１４７１８１号公報（特許文献７）が挙げられる。
【０００４】
これらの、ラミネート缶のフィルムの下地に用いられる鋼板には、多くの場合、電解クロメート処理を施したクロメート被膜が用いられている。クロメート被膜は、２層構造を有し、金属Ｃｒ層の上層に水和酸化Ｃｒ層が存在している。従って、ラミネートフィルム（接着剤付きのフィルムであれば接着層）はクロメート被膜の水和酸化Ｃｒ層を介して鋼板との密着性を確保している。この密着発現の機構についての詳細は必ずしも明確ではないが、水和酸化Ｃｒの水酸基とラミネートフィルムのカルボニル基あるいはエステル基などの官能基との水素結合であると言われている。また、電解クロメート処理を行わない被膜として、特開平１０−４６１０１号公報（特許文献８）が挙げられる。
【０００５】
【引用文献】
（１）特許文献１（特開昭６０−１７０５３２号公報）
（２）特許文献２（特開平３−３２８３５号公報）
（３）特許文献３（特開平２−２６３５２３号公報）
（４）特許文献４（特開昭６０−１６８６４３号公報）
（５）特許文献５（特開平３−２３６９５４号公報）
（６）特許文献６（特開平５−１１１９７９号公報）
（７）特許文献７（特開平５−１４７１８１号公報）
（８）特許文献８（特開平１０−４６１０１号公報）
【０００６】
【発明が解決しようとする課題】
上記の発明は、確かに、地球環境の保全を大きく前進せしめる効果が得られるが、その一方で、近年、飲料容器市場では、ＰＥＴボトル、瓶、紙等の素材とのコスト並びに品質競争が激化しており、上記のラミネート容器用鋼板に対しても、より優れた製缶加工性、特に、フィルム密着性、加工フィルム密着性、耐食性のみならず、従来には無い耐錆性が求められるようになった。
【０００７】
【課題を解決するための手段】
本発明者等は、これらの課題を解決するため、鋼板表面に中間層としてＳｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を施し、その上層にリン酸アルミ化合物を活用した被膜を鋭意検討した。その結果、従来の製品では発錆の起点となる表面処理層の欠陥や疵部、端部において優れた耐錆性を発揮し、更に、フェノール樹脂などの有機樹脂との複合活用により、その上層に施されるラミネートフィルムと非常に強力な共有結合を形成し、従来のクロメート被膜以上の優れた密着性を示し、従来にない優れた製缶加工性が得られることを知見し、本発明に至った。この機構についての詳細は不明であるが、恐らくは、リン酸アルミ化合物と表面処理の相互作用により耐錆性が向上すると同時に有機樹脂との複合効果により優れた密着性や耐食性が確保されたものと考えられる。
【０００８】
すなわち、本発明の要旨は、
（１）少なくとも鋼板片面に、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を有し、その上に、Ｐとして０．０１〜５０ｍｇ／ｍ^２のリン酸アルミ化合物層を有することを特徴とする耐錆性に優れたラミネート容器用鋼板。
（２）少なくとも鋼板片面に、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を有し、その上に、Ｐとして０．００１〜５０ｍｇ／ｍ^２のリン酸アルミ化合物を含むＣ量として０．１〜１００ｍｇ／ｍ^２の有機皮膜層を有することを特徴とする耐錆性に優れたラミネート容器用鋼板。
【０００９】
（３）少なくとも鋼板片面に、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を有し、その上に、Ｐとして０．００１〜５０ｍｇ／ｍ^２のリン酸アルミ化合物を下層にし上層にはＣ量として０．１〜１００ｍｇ／ｍ^２の有機皮膜層を有す二層皮膜を有することを特徴とする耐錆性に優れたラミネート容器用鋼板。
（４）少なくとも鋼板片面に、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を有し、その上に、Ｐとして０．００１〜５０ｍｇ／ｍ^２のリン酸アルミ化合物を含むＣ量として０．１〜１００ｍｇ／ｍ^２の有機皮膜層を下層にし上層にはＣ量として０．１〜１００ｍｇ／ｍ^２有機皮膜層を有す二層皮膜を有することを特徴とする耐錆性に優れたラミネート容器用鋼板。
【００１０】
（５）少なくとも鋼板片面に、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を有し、その上に、Ｐとして０．００１〜５０ｍｇ／ｍ^２のリン酸アルミ化合物を含むＣ量として０．１〜１００ｍｇ／ｍ^２のフェノール系樹脂皮膜を有することを特徴とする耐錆性に優れたラミネート容器用鋼板。
（６）少なくとも鋼板片面に、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を有し、その上に、Ｐとして０．００１〜５０ｍｇ／ｍ^２のリン酸アルミ化合物を下層にし上層にはＣ量として０．１〜１００ｍｇ／ｍ^２のフェノール系樹脂皮膜を有す二層皮膜を有することを特徴とする耐錆性に優れたラミネート容器用鋼板。
【００１１】
（７）少なくとも鋼板片面に、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を有し、その上に、Ｐとして０．００１〜５０ｍｇ／ｍ^２のリン酸アルミ化合物を含むＣ量として０．１〜１００ｍｇ／ｍ^２のフェノール系樹脂皮膜を下層にし上層にはＣ量として０．１〜１００ｍｇ／ｍ^２のフェノール系樹脂皮膜を有す二層皮膜を有することを特徴とする耐錆性に優れたラミネート容器用鋼板。
（８）前記（１）〜（７）において、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含むことを特徴とする表面処理層は、Ｓｎは金属Ｓｎとして８０〜６０００ｍｇ／ｍ^２、Ｎｉは金属Ｎｉとして１０〜８００ｍｇ／ｍ^２、Ｆｅは金属Ｆｅとして１０〜８００ｍｇ／ｍ^２、Ｃｒ及び水和酸化Ｃｒは金属Ｃｒとして２〜２００ｍｇ／ｍ^２である耐錆性に優れたラミネート容器用鋼板にある。
【００１２】
以下に本発明の作用である製缶加工性に優れたラミネート容器用鋼板について詳細に説明する。
本発明で用いられる原板は特に規制されるものではなく、通常、容器材料として使用される鋼板を用いる。この原板の製造法、材質なども特に規制されるものではなく、通常の鋼片製造工程から熱間圧延、酸洗、冷間圧延等の工程を経て製造される。この原板に、Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒを含む表面処理層を付与する方法については特に規制するものでは無く、例えば、電気めっき法や真空蒸着法やスパッタリング法などの公知技術を用いれば良く、拡散層を付与するための加熱処理を組み合わせても良い。
【００１３】
こうして付与されたＳｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層において、Ｓｎは金属Ｓｎとして８０〜６０００ｍｇ／ｍ^２、Ｎｉは金属Ｎｉとして１０〜８００ｍｇ／ｍ^２、Ｆｅは金属Ｆｅとして１０〜８００ｍｇ／ｍ^２、Ｃｒ及び水和酸化Ｃｒは金属Ｃｒとして２〜２００ｍｇ／ｍ^２に規制されるのが望ましい。
Ｓｎは優れた加工性、溶接性を発揮する。この効果が発現するのは金属Ｓｎとして８０ｍｇ／ｍ^２以上とするのが望ましい。十分な溶接性を確保するためには２００ｍｇ／ｍ^２以上、十分な加工性を確保するためには、１０００ｍｇ／ｍ^２以上付与することが望ましい。Ｓｎ付着量の増加に伴い、Ｓｎの優れた加工性、溶接性の向上効果は増加するが、６０００ｍｇ／ｍ^２超ではその向上効果が飽和するため経済面からは望ましくない。従って、Ｓｎの付着量は金属Ｓｎとして６０００ｍｇ／ｍ^２以下にするのが望ましい。
【００１４】
Ｎｉ、Ｆｅは、フィルム密着性、耐食性、溶接性にその効果を発揮し、そのためには、金属ＮｉあるいはＦｅとして、１０ｍｇ／ｍ^２以上のＮｉあるいはＦｅを付着させるのが望ましい。Ｎｉ、Ｆｅの付着量の増加に伴い、Ｎｉ、Ｆｅの優れたフィルム密着性、耐食性、溶接性の向上効果は増加するが、８００ｍｇ／ｍ^２超ではその向上効果が飽和するため経済的に望ましくない。従って、Ｎｉ、Ｆｅの付着量は金属ＮｉあるいはＦｅとして１０ｍｇ／ｍ^２以上、８００ｍｇ／ｍ^２以下とするのが望ましい。
【００１５】
更に、優れたフィルム密着性、耐食性を発揮するＣｒ及び水和酸化Ｃｒは金属Ｃｒとして２〜２００ｍｇ／ｍ^２が望ましい。すなわち、Ｃｒ及び水和酸化Ｃｒの付着量が金属Ｃｒとして２ｍｇ／ｍ^２を下回ると十分な密着性が発揮されにくい。従って、Ｃｒ及び水和酸化Ｃｒの付着量は金属Ｃｒとして２ｍｇ／ｍ^２以上が望ましい。Ｃｒ及び水和酸化Ｃｒの付着量が増加する程、フィルム密着性、耐食性の向上効果は増加するが、２００ｍｇ／ｍ^２を超えると溶接性が劣化してくることから、Ｃｒ及び水和酸化Ｃｒの付着量は金属Ｃｒとして２００ｍｇ／ｍ^２以下にするのが望ましい。
【００１６】
Ｓｎ、Ｎｉ、Ｆｅ、Ｃｒ、水和酸化Ｃｒの１種以上を含む表面処理層を付与した後に、本発明の本質とする処のリン酸アルミ化合物を使用した被膜が付与される。リン酸アルミ化合物を使用した被膜としては、リン酸アルミ化合物単体でも良いが、有機樹脂中にリン酸アルミ化合物を含ませた構造、下層にリン酸アルミ化合物を上層に有機樹脂を有する二層構造、あるいは、下層にリン酸アルミ化合物を含ませた有機樹脂を上層に有機樹脂を有する二層構造によって複合化させることにより、一層優れた相乗効果を発揮させることが出来る。
【００１７】
使用されるリン酸アルミ化合物としては、リン酸アルミ、重リン酸アルミあるいはポリリン酸アルミなどの化合物が挙げられるが、工業的、経済的な側面から使い分ければ良い。
複合化の方法としては、特に規制はしない。例えば、リン酸アルミ化合物を有機樹脂に分散させ、塗布する方法、リン酸アルミ化合物を塗布した後に有機樹脂を塗布する方法、リン酸アルミ化合物を有機樹脂に分散させたものを塗布した後に有機樹脂を塗布する方法が挙げられる。リン酸アルミ化合物を付与することにより、発錆を抑制する効果が発揮されるが、実用的な必要量はＰとして０．００１ｍｇ／ｍ^２以上である。リン酸アルミ化合物が増加に応じて、その効果は向上するがＰとして５０ｍｇ／ｍ^２を超えると経済的に不利である。従ってリン酸アルミ化合物はＰとして０．００１ｍｇ／ｍ^２から５０ｍｇ／ｍ^２にするのが望ましい。
【００１８】
本発明で付与される有機樹脂被膜は、ラミネートされるフィルムあるいは接着層と共有結合を発生し、高い密着性を確保せしめ、リン酸アルミ化合物と相乗効果を発揮する。これらの効果を発揮させるためには、Ｃ量として０．１ｍｇ／ｍ^２以上の有機樹脂を付与するのが望ましい。有機樹脂の被覆量が増加するとこれらの効果も向上するがＣ量として１００ｍｇ／ｍ^２を超えると溶接性等の製缶加工性が阻害される。従って、付与する有機皮膜量はＣ量として０．１ｍｇ／ｍ^２から１００ｍｇ／ｍ^２とするのが望ましい。
【００１９】
この効果が得られる有機樹脂としては、エポキシ系樹脂、フェノール系樹脂、ウレタン系樹脂、ビニル系樹脂、エステル系樹脂、スチレン系樹脂などが挙げられるが、特に優れた性能を発揮する樹脂として、フェノール系樹脂が挙げられる。フェノール系樹脂は常法に製造可能で、例えば、フェノール化合物、ナフトール化合物またはビスフェノール類とホルムアルデヒドを重縮合し製作される。
本発明の有機樹脂においては、種々の樹脂と混合されてもその効果を発揮するが、フェノール系樹脂の優れた特性を発揮するためには、フェノール樹脂分が７０％以上含有する必要がある。
【００２０】
【実施例】
以下に本発明の実施例及び比較例について述べ、その結果を表１に示す。
以下の処理法（１）〜（７）の方法を用いて鋼板上に表面処理層を付与した。
（処理法１）
冷間圧延後、焼鈍、調圧された原板にフェロスタン浴を用いてＳｎめっきを施し、その上に必要に応じてクロム酸−硫酸溶液中で電解処理を行いＣｒまたは水和酸化Ｃｒ付与した。
（処理法２）
冷間圧延後、焼鈍、調圧された原板にワット浴を用いてＮｉめっきを施し、その上に必要に応じてクロム酸−硫酸溶液中で電解処理を行いＣｒまたは水和酸化Ｃｒ付与した。
【００２１】
（処理法３）
冷間圧延後、ワット浴を用いてＮｉめっきを施し、焼鈍時にＮｉ拡散層を形成させ、その後、必要に応じて、クロム酸−硫酸溶液中で電解処理を行いＣｒまたは水和酸化Ｃｒ付与した。
（処理法４）
冷間圧延後、焼鈍、調圧された原板に硫酸−塩酸浴を用いてＦｅめっきを施し、その上に必要に応じてクロム酸−硫酸溶液中で電解処理を行いＣｒまたは水和酸化Ｃｒ付与した。
（処理法５）
【００２２】
冷間圧延後、焼鈍、調圧された原板に、クロム酸−硫酸溶液中で電解処理を行いＣｒまたは水和酸化Ｃｒ付与した。
（処理法６）
冷間圧延後、焼鈍、調圧された原板に硫酸−塩酸浴を用いてＦｅ−Ｎｉ合金めっきを施し、引き続き、フェロスタン浴を用いてＳｎめっきを施し、加熱処理により、Ｓｎめっき層を一部合金化させ、その上に必要に応じてクロム酸−硫酸溶液中で電解処理を行いＣｒまたは水和酸化Ｃｒ付与した。
【００２３】
（処理法７）
冷間圧延後、焼鈍、調圧された原板に硫酸−塩酸浴を用いてＳｎ−Ｎｉ合金を施し、その上に必要に応じてクロム酸−硫酸溶液中で電解処理を行いＣｒまたは水和酸化Ｃｒ付与した。
上記の処理により表面処理層を付与した後、以下の処理法（８）〜（１０）でリン酸アルミ化合物、リン酸アルミ化合物−有機樹脂からなる被膜を付与した。
（処理法８）
重リン酸アルミを溶解させた処理液に上記鋼板を浸漬後、リンガーロールで絞り乾燥させ、所定の被膜を付与した。
【００２４】
（処理法９）
リン酸にフェノール樹脂とリン酸アルミを溶解させた処理液に上記鋼板を浸漬後、リンガーロールで絞り乾燥させ、所定の被膜を付与した。
（処理法１０）
フェノール樹脂と重リン酸アルミを溶解させた処理液に上記鋼板を浸漬後、リンガーロールで絞り乾燥させた後、水溶性の８５％フェノール樹脂−１５％エポキシ樹脂を塗布し乾燥させ、所定の被膜を付与した。
【００２５】
上記処理材について、厚さ２０ｕｍのポリエチレンフィルムを２００℃でラミネートし試験材を作製し、以下に示す（Ａ）〜（Ｅ）の各項目について性能評価を行った。
（Ａ）成形性
試験材に絞り加工としごき加工を段階的に行い、成型を４段階（◎：非常に良い、○：良い、△：疵が認められる、×：破断し加工不能）で評価した。
（Ｂ）溶接性
ワイヤーシーム溶接性を用いて、溶接ワイヤースピード８０ｍ／ｍｉｎの条件で、電流を変更して溶接を実施し、十分な溶接強度が得られる最小電流値とチリ及び溶接スパッタなどの溶接欠陥が目立ち始める最大電流値からなる適正電流範囲の広さから総合的に判断し、４段階（◎：非常に広い、○：良い、△：劣る、×：溶接不能）で溶接性を評価した。
【００２６】
（Ｃ）フィルム密着性
絞りしごき加工を行った試験材に１２５℃、３０ｍｉｎのレトルト処理を行い、フィルムの剥離状況を、４段階（◎：全く剥離無し、○：実用上問題無い程度の極僅かな剥離有り、△：僅かな剥離有り、×：大部分で剥離）で評価した。
（Ｄ）耐食性
試験材に絞りしごき加工を行い、缶を作製し、１．５％クエン酸−１．５％食塩混合液からなる試験液を充填し、蓋を取付け、５５℃、１ヶ月間、恒温室に安置し、缶内面の腐食状況を４段階（◎：腐食が認められない、○：実用上問題無い程度の僅かな腐食が認められる、△：微小な腐食が認められる、×：激しい腐食が認められる）で判断して評価した。
【００２７】
（Ｅ）耐錆性
試験材にクロスカットを入れ、４０℃、８５％の恒温室に１ヶ月間、安置し、試験材の発錆状況を４段階（◎：発錆が認められない、○：実用上問題無い程度の僅かな発錆が認められる、△：微小な発錆が認められる、×：激しい発錆が認められる）で判断して評価した。
【００２８】
【表１】

【００２９】
【発明の効果】
表１に示すように、本発明により製造された製缶加工性に優れたラミネート容器用鋼板は、優れた成形性、溶接性、フィルム密着性、耐食性を有することが明らかになった。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steel sheet for a laminate container which is excellent in draw ironing, weldability, corrosion resistance and film adhesion as a material for can making.
[0002]
[Prior art]
Metal containers used for beverages and foods are roughly classified into two-piece cans and three-piece cans. For a two-piece can represented by a DI can, after being drawn and ironed, painting is performed on the inner surface of the can and painting and printing is performed on the outer surface of the can. In the three-piece can, the surface corresponding to the inner surface of the can is painted, and the surface corresponding to the outer surface of the can is printed, and then the can body is welded. In any of the can types, a painting step is an essential step before and after can making. Solvent-based or water-based paints are used for painting, and then baking is performed. In this painting process, waste (waste solvents, etc.) derived from paints is discharged as industrial waste, and exhaust gas (mainly Carbon dioxide) is released into the atmosphere. In recent years, efforts have been made to reduce these industrial wastes and exhaust gases for the purpose of preserving the global environment. Among them, a technique of laminating a film as an alternative to painting has attracted attention and has rapidly spread.
[0003]
Up to now, in the case of two-piece cans, there have been provided a large number of methods for producing cans by laminating a film and making cans and related inventions. For example, JP-A-60-170532 (Patent Document 1), JP-A-3-32835 (Patent Document 2), JP-A-2-263523 (Patent Document 3), and JP-A-60-168463. (Patent Document 4).
As for the three-piece can, JP-A-3-236954 (Patent Document 5), JP-A-5-111979 (Patent Document 6), and JP-A-5-147181 (Patent Document 7) are exemplified.
[0004]
In many cases, a steel plate used as a base material of a film of a laminated can uses a chromate film subjected to electrolytic chromate treatment. The chromate film has a two-layer structure, and a hydrated chromium oxide layer is present on the metal Cr layer. Therefore, the laminated film (the adhesive layer in the case of a film with an adhesive) secures the adhesion to the steel sheet via the hydrated chromium oxide layer of the chromate film. Although the details of the mechanism of this adhesion development are not always clear, it is said that the mechanism is a hydrogen bond between a hydroxyl group of the hydrated oxidized Cr and a functional group such as a carbonyl group or an ester group of the laminate film. Japanese Patent Application Laid-Open No. H10-46101 (Patent Document 8) is an example of a film that is not subjected to electrolytic chromate treatment.
[0005]
[References]
(1) Patent Document 1 (JP-A-60-170532)
(2) Patent Document 2 (JP-A-3-32835)
(3) Patent Document 3 (JP-A-2-263523)
(4) Patent Document 4 (Japanese Patent Application Laid-Open No. 60-168463)
(5) Patent Document 5 (JP-A-3-236954)
(6) Patent Document 6 (JP-A-5-111979)
(7) Patent Document 7 (JP-A-5-147181)
(8) Patent Document 8 (JP-A-10-46101)
[0006]
[Problems to be solved by the invention]
Although the above-mentioned invention certainly has the effect of greatly advancing the preservation of the global environment, the cost and quality competition with materials such as PET bottles, bottles, and paper have intensified in the beverage container market in recent years. For the above-mentioned steel sheet for a laminated container, it is required that not only superior can processability, especially film adhesion, processed film adhesion, and corrosion resistance, but also rust resistance, which has never existed before, is required. Became.
[0007]
[Means for Solving the Problems]
In order to solve these problems, the present inventors applied a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated Cr oxide as an intermediate layer on the surface of a steel sheet, and formed an aluminum phosphate on the surface treatment layer. The coating film utilizing the compound was studied diligently. As a result, conventional products exhibit excellent rust resistance at the defects, flaws, and edges of the surface treatment layer, which is the starting point of rust generation. Formed a very strong covalent bond with the laminated film to be applied to, exhibiting better adhesion than conventional chromate coatings, and found that unprecedented excellent can processability was obtained, and the present invention Reached. Although the details of this mechanism are unknown, it is presumed that the interaction between the aluminum phosphate compound and the surface treatment improved rust resistance and at the same time ensured excellent adhesion and corrosion resistance due to the combined effect with the organic resin. Conceivable.
[0008]
That is, the gist of the present invention is:
(1) At least one surface of a steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated oxidized Cr, on which 0.01 to 50 mg / m ² of phosphoric acid as P A steel sheet for a laminated container having excellent rust resistance characterized by having an aluminum compound layer.
(2) At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr and hydrated oxidized Cr, on which 0.001 to 50 mg / m ² of phosphoric acid as P A steel sheet for a laminated container having excellent rust resistance, comprising an organic film layer having a C content of 0.1 to 100 mg / m ² containing an aluminum compound.
[0009]
(3) At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr and hydrated oxidized Cr, on which 0.001 to 50 mg / m ² of phosphoric acid as P excellent laminated container steel sheet rust resistance, characterized in that the upper layer was an aluminum compound in the lower layer has a two-layer film having a organic coating layer of 0.1-100 mg / m ² as a C amount.
(4) At least one surface of the steel plate has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated oxidized Cr, on which 0.001 to 50 mg / m ² of phosphoric acid as P It is characterized by having an organic film layer containing 0.1 to 100 mg / m ² as a C content containing an aluminum compound as a lower layer and an upper layer having a two-layer film having an organic film layer as a C amount of 0.1 to 100 mg / m ^2. Steel sheet for laminated containers with excellent rust resistance.
[0010]
(5) At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated oxidized Cr, on which 0.001 to 50 mg / m ² of phosphoric acid as P A steel sheet for a laminated container having excellent rust resistance, comprising a phenolic resin film having a C content of 0.1 to 100 mg / m ² containing an aluminum compound.
(6) At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated oxidized Cr, on which 0.001 to 50 mg / m ² of phosphoric acid as P excellent laminated container steel sheet rust resistance, characterized in that the upper layer was an aluminum compound in the lower layer has a two-layer film having a phenolic resin coating 0.1-100 mg / m ² as a C amount.
[0011]
(7) At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr and hydrated oxidized Cr, on which 0.001 to 50 mg / m ² of phosphoric acid as P A phenolic resin film having a C content of 0.1 to 100 mg / m ² containing an aluminum compound is provided as a lower layer, and an upper layer is provided with a two-layer film having a phenolic resin film having a C amount of 0.1 to 100 mg / m ^2. A steel sheet for laminated containers having excellent rust resistance.
(8) In the above (1) to (7), the surface treatment layer containing at least one of Sn, Ni, Fe, Cr and hydrated chromium oxide, wherein Sn is 80 to 6000 mg / metal Sn. m ^2, Ni is 10~800mg ^/ m 2, Fe is 10~800mg ^/ m 2, Cr and hydrated Cr oxide has excellent rust resistance is 2 to 200 mg / ^{m 2} as metallic Cr as the metal Fe as the metallic Ni In a laminated steel sheet.
[0012]
Hereinafter, the steel sheet for a laminated container having excellent workability in can making, which is an effect of the present invention, will be described in detail.
The original plate used in the present invention is not particularly limited, and a steel plate usually used as a container material is used. The production method, material, and the like of the original sheet are not particularly limited, and the original sheet is produced through the steps of hot rolling, pickling, cold rolling, and the like from a normal slab production step. The method of applying a surface treatment layer containing Sn, Ni, Fe, Cr, and hydrated oxidized Cr to the original plate is not particularly limited, and for example, a known technique such as an electroplating method, a vacuum evaporation method, and a sputtering method. May be used, and heat treatment for providing a diffusion layer may be combined.
[0013]
In the surface treatment layer containing one or more of Sn, Ni, Fe, Cr, and hydrated Cr oxide thus provided, Sn is 80 to 6000 mg / m ² as metal Sn, and Ni is 10 to 800 mg / m ² as metal Ni. , Fe is desirably regulated to 10 to 800 mg / m ² as metal Fe, and Cr and hydrated chromium oxide are desirably regulated to ² to 200 mg / m ² as metal Cr.
Sn exhibits excellent workability and weldability. This effect is desirably achieved when the metal Sn is at least 80 mg / m ² . It is desirable to provide 200 mg / m ² or more in order to secure sufficient weldability, and 1000 mg / m ² or more in order to secure sufficient workability. The effect of improving the excellent workability and weldability of Sn increases with an increase in the amount of Sn attached, but if the amount exceeds 6000 mg / m ² , the effect is saturated, which is not desirable from the economical point of view. Therefore, it is desirable that the amount of Sn deposited be 6000 mg / m ² or less as metal Sn.
[0014]
Ni and Fe exert their effects on film adhesion, corrosion resistance, and weldability. For this purpose, it is desirable to deposit Ni or Fe of 10 mg / m ² or more as metal Ni or Fe. Ni, with the increase of adhesion amount of Fe, Ni, excellent film adhesion Fe, the corrosion resistance, although the effect of improving the weldability is increased, economically undesirable because the improvement effect is saturated at 800 mg / m ² greater Absent. Therefore, it is desirable that the amount of Ni or Fe deposited be 10 mg / m ² or more and 800 mg / m ² or less as metal Ni or Fe.
[0015]
Furthermore, Cr and hydrated oxidized Cr exhibiting excellent film adhesion and corrosion resistance are desirably ² to 200 mg / m ² as metallic Cr. That is, if the adhesion amount of Cr and hydrated Cr oxide is less than ² mg / m ² as metal Cr, sufficient adhesion is difficult to be exhibited. Therefore, it is desirable that the adhesion amount of Cr and hydrated Cr oxide be 2 mg / m ² or more as metal Cr. As the adhesion amount of Cr and hydrated oxidized oxide increases, the effect of improving film adhesion and corrosion resistance increases. However, when the amount exceeds 200 mg / m ² , the weldability deteriorates. Is desirably 200 mg / m ² or less as metal Cr.
[0016]
After providing a surface treatment layer containing at least one of Sn, Ni, Fe, Cr and hydrated oxidized Cr, a coating using the aluminum phosphate compound as the essence of the present invention is provided. The coating using the aluminum phosphate compound may be an aluminum phosphate compound alone, but a structure in which the aluminum phosphate compound is contained in the organic resin, a two-layer structure in which the aluminum phosphate compound is in the lower layer and the organic resin is in the upper layer Alternatively, by synthesizing an organic resin containing an aluminum phosphate compound in the lower layer with a two-layer structure having the organic resin in the upper layer, a more excellent synergistic effect can be exhibited.
[0017]
Examples of the aluminum phosphate compound to be used include compounds such as aluminum phosphate, aluminum biphosphate, and aluminum polyphosphate, which may be used depending on industrial and economic aspects.
There are no particular restrictions on the method of compounding. For example, a method of dispersing and coating an aluminum phosphate compound in an organic resin, a method of applying an organic resin after applying an aluminum phosphate compound, and a method of applying an organic resin after dispersing an aluminum phosphate compound in an organic resin Is applied. By providing the aluminum phosphate compound, an effect of suppressing rusting is exhibited, but a practically necessary amount is 0.001 mg / m ² or more as P. The effect increases as the aluminum phosphate compound increases, but if P exceeds 50 mg / m ² , it is economically disadvantageous. Thus aluminum phosphate compound is preferably to from 0.001 mg / ^{m 2} as P to 50 mg / ^{m 2.}
[0018]
The organic resin film provided in the present invention generates a covalent bond with a film or an adhesive layer to be laminated, ensures high adhesion, and exhibits a synergistic effect with the aluminum phosphate compound. In order to exhibit these effects, it is desirable to provide an organic resin having a C amount of 0.1 mg / m ² or more. When the coating amount of the organic resin increases, these effects also improve. However, when the C amount exceeds 100 mg / m ² , can workability such as weldability is impaired. Therefore, the organic coating amount to impart it is desirable to from 0.1 mg / ^{m 2} and 100 mg / ^{m 2} as a C amount.
[0019]
Examples of the organic resin that can achieve this effect include epoxy resins, phenolic resins, urethane resins, vinyl resins, ester resins, and styrene resins. Base resin. The phenolic resin can be produced by a conventional method, and is produced, for example, by polycondensing a phenol compound, a naphthol compound or a bisphenol with formaldehyde.
The organic resin of the present invention exerts its effect even when mixed with various resins, but in order to exhibit the excellent properties of the phenolic resin, it is necessary that the phenolic resin content is 70% or more.
[0020]
【Example】
Examples of the present invention and comparative examples are described below, and the results are shown in Table 1.
A surface treatment layer was provided on the steel sheet using the following treatment methods (1) to (7).
(Treatment method 1)
After the cold rolling, the annealed and pressure-regulated original plate was subjected to Sn plating using a ferrostan bath, and then subjected to electrolytic treatment in a chromic acid-sulfuric acid solution as needed to provide Cr or hydrated Cr oxide.
(Treatment method 2)
After cold rolling, the annealed and pressure-regulated original plate was subjected to Ni plating using a Watt bath, and an electrolytic treatment was performed thereon in a chromic acid-sulfuric acid solution as required to provide Cr or hydrated Cr oxide.
[0021]
(Treatment method 3)
After cold rolling, Ni plating was performed using a Watt bath, and a Ni diffusion layer was formed at the time of annealing. Thereafter, if necessary, electrolytic treatment was performed in a chromic acid-sulfuric acid solution to provide Cr or hydrated Cr oxide. .
(Treatment method 4)
After cold rolling, the annealed and pressure-regulated original plate is subjected to Fe plating using a sulfuric acid-hydrochloric acid bath, and electrolytic treatment is performed thereon in a chromic acid-sulfuric acid solution as necessary to provide Cr or hydrated Cr oxide. did.
(Processing method 5)
[0022]
After cold rolling, the annealed and pressure-regulated original plate was subjected to electrolytic treatment in a chromic acid-sulfuric acid solution to give Cr or hydrated Cr oxide.
(Treatment method 6)
After cold rolling, the annealed and pressure-regulated original plate is subjected to Fe-Ni alloy plating using a sulfuric acid-hydrochloric acid bath, followed by Sn plating using a ferrostan bath, and heat treatment to partially remove the Sn plating layer. The alloy was formed, and then, if necessary, electrolytic treatment was performed in a chromic acid-sulfuric acid solution to give Cr or hydrated Cr oxide.
[0023]
(Processing method 7)
After cold rolling, the annealed and pressure-regulated original plate is subjected to a Sn-Ni alloy using a sulfuric acid-hydrochloric acid bath, and then subjected to electrolytic treatment in a chromic acid-sulfuric acid solution as necessary, thereby performing Cr or hydration oxidation. Cr was added.
After the surface treatment layer was applied by the above-described treatment, a coating comprising an aluminum phosphate compound, an aluminum phosphate compound and an organic resin was applied by the following treatment methods (8) to (10).
(Processing method 8)
The steel sheet was immersed in a treatment solution in which aluminum biphosphate was dissolved, squeezed and dried with a ringer roll, and a predetermined coating was applied.
[0024]
(Processing method 9)
The steel sheet was immersed in a treatment solution in which a phenol resin and aluminum phosphate were dissolved in phosphoric acid, squeezed and dried with a ringer roll, and a predetermined coating was applied.
(Processing method 10)
After immersing the steel sheet in a treatment solution in which a phenol resin and aluminum biphosphate are dissolved, squeezing and drying with a ringer roll, a water-soluble 85% phenol resin-15% epoxy resin is applied and dried, and a predetermined coating is formed. Was given.
[0025]
For the above treated material, a polyethylene film having a thickness of 20 μm was laminated at 200 ° C. to prepare a test material, and performance evaluation was performed for each of the following items (A) to (E).
(A) Formability Test material was subjected to drawing and ironing stepwise, and molding was evaluated in four stages (◎: very good, ○: good, Δ: flaws recognized, ×: broken and unworkable) did.
(B) Weldability Using the wire seam weldability, the welding is carried out by changing the current under the condition of a welding wire speed of 80 m / min, and the minimum current value at which sufficient welding strength can be obtained, and dust and welding spatter. Judging comprehensively from the width of the appropriate current range consisting of the maximum current value at which welding defects begin to stand out, the weldability is evaluated in four stages (◎: very wide, ○: good, Δ: poor, ×: impossible to weld) did.
[0026]
(C) Film adhesion The test material subjected to the drawing and ironing process was subjected to a retort treatment at 125 ° C. for 30 minutes, and the peeling state of the film was evaluated in four stages (（: no peeling at all, 極: extremely slight enough to have no practical problem)剥離: Slight peeling, ×: Most peeled).
(D) Squeeze and iron the corrosion resistance test material to prepare a can, fill it with a test solution consisting of a 1.5% citric acid-1.5% salt mixture, attach a lid, and install at 55 ° C for 1 month , Placed in a constant temperature room, the corrosion state of the inner surface of the can was evaluated in four stages (◎: no corrosion was observed, ○: slight corrosion was observed to the extent that there was no practical problem, Δ: minute corrosion was observed, ×: Severe corrosion was observed).
[0027]
(E) A cross-cut was placed on the rust-resistant test material, and was placed in a constant temperature room at 40 ° C. and 85% for one month, and the rusting state of the test material was evaluated in four stages (（: no rusting was observed, ○). : Slight rusting to the extent that there is no practical problem was observed, Δ: Fine rusting was observed, ×: Vigorous rusting was observed).
[0028]
[Table 1]

[0029]
【The invention's effect】
As shown in Table 1, it was revealed that the steel sheet for a laminated container manufactured by the present invention and having excellent workability in can making had excellent formability, weldability, film adhesion, and corrosion resistance.

Claims

At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr and hydrated oxidized Cr, on which an aluminum phosphate compound layer having a P content of 0.01 to 50 mg / m ^2. A laminated steel sheet having excellent rust resistance, characterized by having:

At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated Cr oxide, on which an aluminum phosphate compound of 0.001 to 50 mg / m ² as P is added. A steel sheet for a laminated container having excellent rust resistance, comprising an organic coating layer having a C content of 0.1 to 100 mg / m ² .

At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated Cr oxide, on which an aluminum phosphate compound of 0.001 to 50 mg / m ² as P is added. A steel sheet for a laminated container having excellent rust resistance, comprising a lower layer and an upper layer having a two-layer coating having an organic coating layer having a C content of 0.1 to 100 mg / m ² .

At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated Cr oxide, on which an aluminum phosphate compound of 0.001 to 50 mg / m ² as P is added. An organic film layer having a C content of 0.1 to 100 mg / m ² as a lower layer, and an upper layer having a two-layer film having an organic film layer of 0.1 to 100 mg / m ² as a C amount. Excellent rust-resistant steel sheet for laminated containers.

At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated Cr oxide, on which an aluminum phosphate compound of 0.001 to 50 mg / m ² as P is added. A steel sheet for a laminate container having excellent rust resistance, comprising a phenolic resin film having a C content of 0.1 to 100 mg / m ² .

At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated Cr oxide, on which an aluminum phosphate compound of 0.001 to 50 mg / m ² as P is added. excellent laminated container steel sheet rust resistance, characterized in that the upper layer to the lower layer having a two-layer film having a phenolic resin coating 0.1-100 mg / m ² as a C amount.

At least one surface of the steel sheet has a surface treatment layer containing at least one of Sn, Ni, Fe, Cr, and hydrated Cr oxide, on which an aluminum phosphate compound of 0.001 to 50 mg / m ² as P is added. A phenolic resin film having a C content of 0.1 to 100 mg / m ² as a lower layer, and an upper layer having a phenolic resin film having a C amount of 0.1 to 100 mg / m ² as a lower layer. Excellent steel sheet for laminated containers.

The surface treatment layer characterized by containing at least one of Sn, Ni, Fe, Cr, and hydrated Cr oxide, wherein Sn is 80 to 6000 mg / m ² as metal Sn and Ni is 10 to 800 mg / m as metal Ni. ² , Fe is 10 to 800 mg / m ² as metal Fe, and Cr and hydrated oxidized Cr are ² to 200 mg / m ² as metal Cr, and is excellent in rust resistance according to claim 1 to 7. Steel sheet for laminated containers.