JPH0137428B2

JPH0137428B2 -

Info

Publication number: JPH0137428B2
Application number: JP61112738A
Authority: JP
Inventors: Hiroshi Ishikawa; Hiroshi Takano; Ryosuke Ootomo; Yoshinori Hoshino; Taro Ooyama
Original assignee: Toyo Ink Mfg Co Ltd; Nippon Kokan Ltd
Current assignee: JFE Engineering Corp; Artience Co Ltd
Priority date: 1986-02-27
Filing date: 1986-05-19
Publication date: 1989-08-07
Also published as: JPS62275172A

Description

[Detailed description of the invention]

〔発明の技術分野〕この発明は、円形状に打ち抜かれた鋼板、表面
処理鋼板またはアルミニウム板等の金属板を、絞
り加工によつてカツプ状に成形し、次いで、この
ように成形されたカツプ状成形品の側壁を、アイ
アニング加工により薄く成形することからなる
DI缶、および、円形状に打ち抜かれた金属板を
２回の絞り加工によつて成形することからなる
DRD缶のような、２ピース缶の製造のための、
前記金属板の表面に予め塗装されるプレコート用
塗料、および、その表面に前記プレコート用塗料
による塗膜が形成された２ピース缶用プレコート
金属板に関するものである。〔従来技術とその問題点〕例えば、錫メツキ鋼板やアルミニウム板等の素
材を、絞り加工（ドローイング）によつてカツプ
状に成形し、次いで、このカツプ状成形品の側壁
をしごき加工（アイアニング）することからなる
DI成型加工法によつて製造されるDI缶（Drawn
and Ironed Can）は、はんだ付けされた胴に底
蓋と上蓋とを巻締めにより一体化した、いわゆる
３ピース缶に比べて肉厚が薄いので軽量であり、
且つ継目がないので漏れがない等の利点から、そ
の需要が多く、今後その用途も拡大することが予
想される。 DI缶の素材として、従来、錫めつき鋼板やア
ルミニウム板が使用されており、錫めつき鋼板は
アルミニウム板に比べて安価である点から、その
需要の伸びが期待されている。しかしながら、錫
めつき鋼板においても、錫の付着量が通常2.8〜
5.6ｇ／m²であり、最近に電力や錫にコストの高
騰のため、製造コストの上昇が避けられず、低コ
ストでしかも耐食性に優れたDI缶用素材の開発
が強く臨まれている。一方、DI缶の製造過程において、カツプ状に
成形された材料のアイアニング加工は、極めて厳
しく、板厚の減少率は約70％になる。そして、ア
イアニング加工される材料は、優れた潤滑性を有
していることが必要であり、この潤滑性を付与す
るために、錫は効果的である。従つて、上述した製造原価の低減を図るために
錫の付着量を少なくすると、錫層による延性効果
が劣化する結果、潤滑性能が低下して、アイアニ
ング加工時に、ダイスを通る材料の摩擦熱による
焼付きや、材料がダイスにかみ込む“かじり”が
発生する。このような焼付きや“かじり”が発生
した缶は、耐食性が劣化し、使用に耐えない。更に、錫の付着量が少ないと、製缶後に、缶表
面に付着した潤滑剤等の油分を除去するための脱
脂作業が行なわれた後、次工程に移るまでの間に
錆が発生しやすい。一方、円形状に打ち抜かれた鋼板を２回の絞り
加工によつて成形することからなるDRD成形法
によつて製造されたDRD缶（Draw and
Redrawn Can）は、成形加工時に塗膜に生ずる
クラツクにより、内容物を入れた後の耐食性に問
題がある。上述した問題を解決する手段として、例えば、
特開昭51−63787号公報において、エポキシフエ
ノール系、エポキシ尿素ホルムアルデヒド系、ビ
ニル系オルガノゾルおよびビニル系溶液の樹脂を
含む塗料、または、前記塗料中に内部潤滑剤が添
加された塗料を、素材に部分的にキユアリングさ
せた後、DI成形加工する方法が開示されている。
更に、特公昭60−4753号公報において、表面処理
鋼板に、エポキシフエノール系塗料、または、前
記塗料中に有機系潤滑剤が添加された塗料を、部
分的にキユアリングさせた後、DI成形加工する
方法が開示されている。しかしながら、上述した方法は何れも塗料のキ
ユアリングが部分的であるため、缶に充填された
飲料等の内容物の味や芳香（以下フレーバーとい
う）が劣化し、且つ、塗膜の耐色性が悪い等の問
題を有している。そこで、厳しいDI成形加工が施されても塗膜
が損傷せず、優れた潤滑性および耐食性を有し且
つ安価な、プレコート用塗料、および、このよう
な塗料による塗膜をその表面に有する２ピース缶
用プレコート金属板の開発が強く望まれている
が、かかる特性を具備したプレコート用塗料およ
び２ピース缶用プレコート金属板は、未だ提案さ
れていない。〔発明の目的〕従つて、この発明の目的は、厳しいDI成形加
工またはDRD成形加工が施されても塗膜が損傷
せず、優れた潤滑性および耐食性を有し且つ安価
な、プレコート用塗料、および、このような塗料
による塗膜がその少なくとも１つの表面上に形成
された２ピース缶用プレコート金属板を提供する
ことにある。本発明者等は、先ず潤滑性能に寄与する、鋼板
の最上層の塗膜の性状について研究を行なつた結
果、次のことがわかつた。即ち、DI成形加工に
おけるDI成形性は、低圧下領域での摩擦係数を
減少させても向上せず、高圧下領域における潤滑
性能に左右される。従つて、鋼板の最上層の塗膜
の性能として、高圧下での伸び性、下地材との密
着性、塗膜自体の潤滑性が必要であり、更に、ア
イアニング加工時においてダイスと鋼板との間に
存在する外部潤滑剤（クーラント）の保持作用を
高め、外部潤滑剤のもつ機能を充分に発揮させる
ことが必要とされる。本発明者等は、上述した条件を満たす塗膜を形
成することができる塗料を得べく研究の結果、内
部潤滑剤としての、フツ素原子置換オレフイン系
重合体変性炭化水素系ワツクス粒子が添加分散さ
れた熱硬化性塗料が最適であることを知見した。〔発明の概要〕この発明は、上記知見に基いてなされたもので
あつて、熱硬化性塗料中に、内部潤滑剤として
の、融点が70〜200℃であるフツ素原子置換オレ
フイン系重合体変性炭化水素系ワツクス粒子が、
前記熱硬化性塗料の固形分100重量部に対して、
0.1〜30重量部の割合で添加されてなるプレコー
ト用塗料、および、前記プレコート用塗料による
塗膜が、金属板の少なくとも１つの表面上に形成
されてなる２ピース缶用プレコート金属板である
ことに特徴を有するものである。〔発明の構成〕この発明における、熱硬化性塗料としては、熱
硬化性樹脂であるフエノール樹脂またはエポキシ
樹脂を配合してなる塩化ビニル樹脂系オルガノゾ
ル塗料、および、エポキシ系樹脂とフエノール樹
脂、エポキシ系樹脂とアミノ樹脂、ポリエステル
系樹脂とアミノ樹脂、エポキシ系樹脂とアクリル
樹脂およびエポキシエステル系樹脂とアミノ樹脂
の各々の組合わせのうちの何らか１つからなる缶
用塗料が使用される。上述した塗料に、内部潤滑剤としての、フツ素
原子置換オレフイン系重合体変性炭化水素系ワツ
クス粒子を添加する理由は、塗膜に潤滑性を与
え、高圧下領域で行なわれるDI成形加工時の潤
滑性能が高められるためである。通常、塗膜の潤滑性能を高めるための内部潤滑
剤として、塗膜の動摩擦係数を下げるために使用
される。みつロウ、鯨ロウ、牛脂、カルナバワツ
クス、ラノリンワツクスのような動物性または植
物性の潤滑剤、および、ポリエチレンのワツクス
を使用したのでは、DI成形加工時の塗膜に十分
な潤滑性能を与えることができず、成形性を向上
させることができない。また、上記塗膜の潤滑性能を高めるための内部
潤滑剤として、フツ素原子置換オレフインのワツ
クスたとえばポリテトラフルオロエチレンのワツ
クスを使用したのでは、その融点が300℃以上で
高いために、焼付けされた塗膜の表面上に固体状
のワツクスが残るため極度の凹凸が生じ、コスト
的にも不利である。しかも、このようなワツクス
は、表面自由エネルギーの低い塗膜表面を構成す
るために、撥水性および撥油性が強く、缶に成形
加工後、缶の内外面に行なわれる塗装に問題が生
ずる。変性炭化水素系ワツクスとしては、ポリエチレ
ン、ポリプロピレンなどの低分子量ポリオレフイ
ンのような炭化水素系ワツクスを、テトラフルオ
ロエチレン、トリフルオロエチレン、ヘキサフル
オロプロピレンなどのフツ素原子置換オレフイン
の重合体により変性した常温で固体状のワツクス
が使用される。変性の例としては、炭化水素系ワツクスの粒子
をフツ素原子置換オレフイン重合体の微粒子と
を、ジエツトミルのような強力な機械装置によつ
て混合処理する方法がある。このようにして得ら
れた変性炭化水素ワツクスは、炭化水素系ワツク
ス粒子表面にフツ素原子置換オレフイン重合体が
結合したワツクス粒子となる。このような物理的
処理による変性炭化水素ワツクスの例としては、
ジヨージ．M.ランガーアンドカンパニーから市
販されているポリテトラフルオロエチレン変性マ
イクロクリスタリンワツクス（商品名：ランコワ
ツクスTF1778、TF1780等）をあげることができ
る。上述した変性炭化水素系ワツクス粒子の融点
は、70℃から200℃の範囲内であることが必要で
ある。ここで、ワツクス粒子の融点とは、ワツク
ス粒子が、粒子としての形状を保つことができず
に流動性を示す温度である。前記融点が70℃未満
では、塗料への添加方法や保存条件によつては、
液体となつて塗料中で分離したり、焼付けられた
塗膜に層状の分離が生じて、DI成形時の高圧下
領域における潤滑性能が十分に発揮されない。一
方、前記融点が200℃を越えると、焼付けられた
塗膜中にワツクスがそのままの形で残るため、塗
膜の表面上に極度の凹凸が生じるほか、DI成形
時に高圧下領域において発生する熱でワツクス粒
子が溶融して無くなるため、塗膜に十分な潤滑性
能を保持させることができない。熱硬化性塗料に対する、内部潤滑剤としての、
上述した変性炭化水素系ワツクス粒子の添加割合
は、塗料固形分100部に対して、0.1〜30部である
ことを必要とする。前記添加割合が0.1部未満で
は、DI成形加工時に塗膜に十分な潤滑性能を与
えることができず、成形性が劣化し、最悪の場合
は、成形加工時に“かじり”が発生する。一方、
前記添加量が30部を超えると、チキソトロピツク
性が強くなつて塗装性に問題が生じ、且つ、経済
的にも不利となる。前記塗料に添加される前記変性炭化水素系ワツ
クスは、１〜5μｍの微粒子であることが望まし
い。前記変性炭化水素系ワツクスの粒度が5μｍ
を超えて大きいと、焼付け時に十分ワツクスが溶
けず、固体のまま塗膜中に残り、極度の凹凸が発
生する。更に、塗料の保存性の点からもワツクス
の分散安定性に問題が生ずる。一方、前記粒度を
1μｍ未満にすることはコスト高となり実用的で
はない。上述した塗料による塗膜が形成されるプレコー
ト金属板は、表面処理の施されていない冷延鋼板
であつても、錫、ニツケル、クロム等のメツキが
施された表面処理鋼板であつても、または、アル
ミニウム板であつてもよい。特に、クロムメツキ
鋼板は、塗膜密着性および耐食性が良好である点
から好ましい。上記表面処理鋼板の少なくとも一方の面に、本
発明の、上述した変性炭化水素系ワツクス粒子が
添加されている塗料からなる塗膜が形成されてい
るプレコート鋼板は、前記塗膜によつて表面処理
皮膜が保護されているので、DI成形加工時に前
記表面処理皮膜がダイスに直接接触することはな
い。従つて、DI成形加工後においても、前記表
面処理皮膜は、連続的且つ均一な状態で保持され
ている。この発明のプレコート金属板において、缶体の
外面となるべき一方の表面上には、熱硬化性塗料
中に、内部潤滑剤としての、上述した変性炭化水
素系ワツクス粒子が添加されている、本発明のプ
レコート用塗料からなる塗膜が形成され、そして
缶体の内面となるべき他方の表面上には、熱硬化
性塗料中に、実質的に内部潤滑剤が添加されてい
ないプレコート用塗料からなる塗膜が形成されて
いることが、成形性を向上させる点から望まし
い。その理由は、次の通りである。即ち、成形加工
時に、ダイスに直接接触する、缶体の外面となる
べき一方の表面上に形成された塗膜と、ポンチで
おさえこむ、缶体の内面となるべき他方の表面上
に形成された塗膜との間に、相対的に高圧下での
潤滑性の効果に差を生じさせることによつて、ポ
ンチでおさえこむ塗膜側即ち缶体の内面となる側
に発生する摩擦力等の差が、実質的に成形性の向
上に寄与すると推測される。更に、上述のように、缶体の内面となるべき他
方の表面上に形成される塗膜のための塗料とし
て、内部潤滑剤が添加されていない塗料を使用す
ることは、経済的なメリツトも得られる。 DI成形加工して得られた成形缶は、缶内への
充填物が乾燥物及び缶を腐食させる性質の弱い液
体等の場合には、成形加工後も塗膜が均一に残つ
ているので、トツプコートを施さなくてもよい。
但し、缶内への充填物が、缶を腐食させる性質の
強い液体やフレーバーを重要視するような物の錫
合には、トツプコートを施すことがよい。このように、本発明のプレコート鋼板は、缶内
への充填物によつてはトツプコートを必要としな
いから、この場合には、製缶時におけるトツプコ
ートのための工程が削減され、極めて経済的であ
る。鋼板の表面上に対する本発明のプレコート用塗
料の塗染は、ロールコート、スプレーコート、浸
漬塗装、カーテンフローコート等、公知の塗装手
段によつて行なうことができる。通常、コイル状
の鋼板に対する塗装はリバースロールコータによ
り、シート状の鋼板に対する塗装はナチユラルロ
ールコーターにより行なわれる。このようにして塗装された塗料の焼付けは、
150〜400℃の熱風によつて、10秒〜10分間程度加
熱することにより行なわれる。なお、前記焼付け
は、赤外線加熱、高周波誘導加熱等を単独または
併用して行なつてもよく、このような手段によれ
ば、更に短時間で焼付けを行なうことができる。鋼板の表面上に形成された塗膜層の厚さは、片
面１〜10μｍの範囲内が望ましい。即ち、前記厚
さが1μｍ未満では、DI成形加工時に塗膜が切れ
て、塗膜の連続性が保たれにくく、成形性が悪く
なり、最悪の場合は“かじり”が発生する。一
方、前記厚さが10μｍを超えると、成形時に塗膜
にビルドアツプ現象が生じやすく、経済性の面か
ら好ましくない。両面塗装の場合は、表面と裏面
の塗膜量が同一でもまたは異なつていてもよい。なお、DI成形加工は、従来と同じように、素
材をドローイングによりカツプ状に成形した後、
アイアニング加工により側壁部を延伸し、所定形
状に成形することによつて行なわれる。DI成形
加工後は、充填される物に応じて、ビニル系、エ
ポキシ−アクリル系等の公知の塗料によりトツプ
コートを施してもよい。また、必要に応じて、そ
の外面に白色塗料によるホワイト塗装、印刷、仕
上げ塗装等の仕上げ加工を施してもよい。なお、缶体の外面となるべき一方の表面上に形
成される塗膜のための塗料中に、予め白色塗料を
添加しておけば、上述した仕上げ加工を施さなく
てもまたは僅かな仕上げ加工によつて、ホワイト
塗装を施すことができる。〔発明の実施例〕次に、この発明を、実施例によつて更に詳述す
る。本発明のプレコート用塗料として、下記本発明
塗料Ａ−１〜Ｅと、比較のための、本発明の範囲
外の下記比較塗料Ｆ〜Ｊとを調製した。実施例本発明塗料Ａ−１（塩化ビニル樹脂系オルガノ
ゾル塗料）熱硬化性塗料塩化ビニルペーストレジン：商品名．スミリツ
トEX−13（住友化学株式会社製）……45部
（重量部、以下同じ。）フエノール樹脂：商品名．ヒタノール4020（日
立化成株式会社製）……10部ポリエステル系可塑剤：商品名．ポリサイザー
Ｐ−202（大日本インキ化学株式会社製）……
20部オイルフリーアルキツド樹脂：商品名．アルマ
テツクスＰ−646（三井東圧株式会社製）……
25部テフロン変性ポリエチレン系ワツクス：商品
名．ランコワツクスTF1778 融点：100゜〜
110℃（ジヨージ．M.ランガーアンドカンパ
ニー製）……熱硬化性塗料固形分100部に対
し20部有機スズ系安定剤……塩化ビニル樹脂100部
に対し1.6部上記フエノール樹脂、可塑剤、オイルフリーア
ルキツド樹脂および安定剤を、キシレン：40％
（重量％、以下同じ）、セロソルブアセテート：30
％、ジイソブチルケトン：30％からなる混合溶剤
に溶解後、塩化ビニルペーストレジン、テフロン
変性ポリエチレン系ワツクスを高速で撹拌させな
がら添加、分散せしめ、固形分約45％、粘度90秒
（25℃フオードカツプNo.４）の塩化ビニル樹脂系
オルガノゾル塗料（本発明塗料Ａ−１）を調製し
た。本発明塗料Ａ−２（塩化ビニル樹脂系オルガノ
ゾル塗料）上述した本発明塗料Ａ−１において、テフロン
変形ポリエチレン系ワツクスの添加量を、熱硬化
性塗料固形分100部に対し10部としたほかは、本
発明塗料Ａ−１と同じ成分の塩化ビニル樹脂系オ
ルガノゾル塗料（本発明塗料Ａ−２）を調製し
た。本発明塗料Ａ−３（塩化ビニル樹脂系オルガノ
ゾル塗料）上述した本発明塗料Ａ−１において、テフロン
変性ポリエチレン系ワツクスの添加量を、熱硬化
性塗料固形分100部に対し５部としたほかは、本
発明塗料Ａ−１と同じ成分の塩化ビニル樹脂系オ
ルガノゾル塗料（本発明塗料Ａ−３）を調製し
た。本発明塗料Ｂ（塩化ビニル樹脂系オルガノゾル
塗料）熱硬化性塗料塩化ビニルペーストレジン：商品名．スミリツ
トEX−13（住友化学株式会社製）……40部フエノール樹脂：商品名．ヒタノール4020（日
立化成株式会社製）……16部塩化ビニル・酢酸ビニル・マレイン酸共重合
体：商品名．ビニライトVMCC（ユニオン・カー
バイド社製）……40部ビスフエノールＡ型エポキシ樹脂：商品名．エ
ピコート828（油化シエルエポキシ株式会社
製）……４部テフロン変性ポリエチレン系ワツクス：商品
名．ランコワツクスTF1778（ジヨージ．M.
ランガーアンドカンパニー製）……塗料固形
分100部に対し20部上記フエノール樹脂、塩化ビニル・酢酸ビニ
ル・マレイン酸共重合体およびエポキシ樹脂を、
キシレン：40％、セロソルブアセテート：30％、
ジイソブチルケトン：30％からなる混合溶剤に溶
解後、塩化ビニルペーストレジン、テフロン変性
ポリエチレン系ワツクスを高速で撹拌させながら
添加、分散せしめ、固形分約30％、粘度110秒
（25℃フオードカツプNo.４）の塩化ビニル樹脂系
オルガノゾル塗料（本発明塗料Ｂ）を調製した。本発明塗料Ｃ（エポキシフエノール系塗料）熱硬化性塗料ビスフエノールＡ型エポキシ樹脂：商品名．エ
ピコート1009（油化シエルエポキシ株式会社
製）……80部フエノール樹脂：商品名．ヒタノール4020（日
立化成株式会社製）……20部テフロン変性ポリエチレン系ワツクス：商品
名．ランコワツクスTF1778（ジヨージ．M.
ランガーアンドカンパニー製）……塗料固形
分100部に対し20部上記ビスフエノールＡ型エポキシ樹脂およびフ
エノール樹脂をキシレン：12％、セロソルブアセ
テート：55％、Ｎ−ブタノール10％、シクロヘキ
サン：23％からなる混合溶剤に溶解後、テフロン
性ポリエチレン系ワツクスを高速で撹拌させなが
ら添加、分散せしめ、固形分約30％、粘度70秒
（25℃フオードカツプNo.４）エポキシフエノール
樹脂系塗料（本発明塗料Ｃ）を調製した。本発明塗料Ｄ（エポキシアミノ系塗料）熱硬化性塗料ビスフエノールＡ型エポキシ樹脂：商品名．エ
ピコート1007（油化シエルエポキシ株式会社
製）……90部尿素ホルムアルデヒド樹脂：商品名．メラン
11E（日立化成株式会社製）……10部テフロン変性ポリエチレン系ワツクス：商品
名．ランコワツクスTF1778（ジヨージ．M.
ランガーアンドカンパニー製）……塗料固形
分100部に対し20部上記ビスフエノールＡ型エポキシ樹脂、尿素ホ
ルムアルデヒド樹脂をジアセトンアルコール
DAA：15％、メチルイソブチルカルビニー
ル：７％、エチルセロソルブ：78％からなる混合
溶剤に溶解後、テフロン変性ポリエチレン系ワツ
クスを高速で撹拌させながら添加、分散せしめ、
固形分約30％、粘度50秒（25℃フオードカツプNo.
４）のエポキシアミノ樹脂系塗料（本発明塗料
Ｄ）を調製した。本発明塗料Ｅ（ポリエステルアミノ系塗料）熱硬化性塗料ポリエステル樹脂：商品名．バイロンRV560
（東洋紡株式会社製）……70部ベンゾグアナミン樹脂：商品名．メラン366（日
立化成株式会社製）……25部ビスフエノールＡ型エポキシ樹脂：商品名．エ
ピコート828（油化シエルエポキシ株式会社
製）……５部テフロン変性ポリエチレン系ワツクス：商品
名．ランコワツクスTF1778（ジヨージ．M.
ランガーアンドカンパニー製）……塗料固形
分100部に対し20部上記ポリエステル樹脂、ベンゾグアナミン樹脂
およびビスフエノールＡ型エポキシ樹脂を、キシ
レン：50％、セロソルブアセテート：50％からな
る混合溶剤に溶解後、テフロン変性ポリエチレン
系ワツクスを高速で撹拌させながら添加、分散せ
しめ、固形分約30％、粘度40秒（25℃フオードカ
ツプNo.４）のポリエステルアミノ樹脂系塗料（本
発明塗料Ｅ）を調製した。比較例比較塗料Ｆ（塩化ビニル樹脂系オルガノゾル塗
料）前述した本発明塗料Ａ−１において、テフロン
変性ポリエチレン系ワツクスの代りに、融点が
326℃のポリテトラフルオロエチレンワツクス
（ダイキン工業株式会社製ルブロンＬ−５）を20
部使用したほかは、本発明塗料Ａ−１と同じ成分
の塩化ビニル樹脂系オルガノゾル塗料（比較塗料
Ｆ）を調製した。比較塗料Ｇ（塩化ビニル樹脂系オルガノゾル塗
料）前述した本発明塗料Ａ−１において、テフロン
変性ポリエチレン系ワツクスの代りに、融点が65
℃のマイクロクリスタリンワツクス（東洋ペトロ
ライト株式会社製ウルトラフレツクスアンバー）
を20部使用したほかは、本発明塗料Ａ−１と同じ
成分の塩化ビニル樹脂系オルガノゾル塗料（比較
塗料Ｇ）を調製した。比較塗料Ｈ（塩化ビニル樹脂系オルガノゾル塗
料）前述した本発明塗料Ａ−１において、テフロン
変性ポリエチレン系ワツクスの代りに、ラノリン
（吉川製油株式会社製ハードラノリン）を20部使
用したほかは、本発明塗料Ａ−１と同じ成分の塩
化ビニル樹脂系オルガノゾル塗料（比較塗料Ｈ）
を調製した。比較塗料Ｉ（エポキシフエノール系塗料）前述した本発明塗料Ｃにおいて、テフロン変性
ポリエチレン系ワツクスを除いたほかは本発明塗
料Ｃと同じ成分のエポキシフエノール系塗料（比
較塗料Ｉ）を調製した。比較塗料Ｊ（塩化ビニル樹脂系オルガノゾル塗
料）前述した本発明塗料Ａ−１において、テフロン
変性ポリエチレン系ワツクスを除いたほかは、本
発明塗料Ａ−１と同じ成分の塩化ビニル樹脂系オ
ルガノゾル塗料（比較塗料Ｊ）を調製した。上述した本発明塗料Ａ−１〜Ｅおよび比較塗料
Ｆ〜Ｊを塗装するための金属板として、下記(イ)お
よび(ロ)に示す表面処理鋼板を調製した。 (イ) 板厚0.3mmの低炭素冷延鋼板の両表面の各々
を、通常の電解脱脂および電解酸洗によつて清
浄した後、鋼板を陰極として、70ｇ／の
CrO₃と、2.0ｇ／のNH₄F水溶液により、液
温50℃電流密度30ASDで１秒間電解し、前記
鋼板の両表面の各々に、50mg／m²の金属クロム
層と、その上面に15mg／m²のクロム水和酸化物
層とを形成した。 (ロ) 上記(イ)と同じ冷延鋼板の両表面の各々を、通
常の電解脱脂および電解酸洗によつて清浄した
後、鋼板を陰極として、通常のフエロスタンメ
ツキ浴（Sn²⁺：30ｇ／、遊離酸：硫酸換算
で15ｇ／、ENSA：５ｇ／）により、液温
40℃、電流密度6ASDで１秒間電解し、前記鋼
板の両表面の各々に0.34ｇ／m²の金属錫メツキ
層を形成した。次いで、この錫メツキ鋼板を陰
極とし、30ｇ／のCrO₃水溶液中において、
液温50℃、電流密度30ASDで１秒間電解し、
前記金属錫メツキ層の上面に15mg／m²のクロム
水和酸化物層を形成した。前述した本発明塗料Ａ−１〜Ｅおよび比較塗料
Ｆ〜Ｊと、上記表面処理鋼板(イ)、(ロ)および表面処
理が施されていない冷延鋼板とを、下記第１表の
ように組合わせ、実施例１〜12のプレコート鋼板
と、比較例１〜４のプレコート鋼板とを調製し
た。プレコート鋼板の調製は、鋼板の両面、前記本
発明塗料または前記比較塗料を、5μｍの厚さに
ロールコータで塗装し、次いで、箱型オーブン炉
において、205℃の温度で10分間焼付けることに
より行なつた。 [Technical Field of the Invention] The present invention involves forming a circularly punched metal plate, such as a steel plate, a surface-treated steel plate, or an aluminum plate, into a cup shape by drawing, and then forming the thus formed cup into a cup shape. It consists of forming the side wall of a shaped molded product thinly by ironing process.
Consists of forming a DI can and a metal plate punched into a circular shape by drawing twice.
For the production of two-piece cans, such as DRD cans,
The present invention relates to a precoat paint that is applied on the surface of the metal plate in advance, and a precoat metal plate for two-piece cans on which a coating film of the precoat paint is formed on the surface. [Prior art and its problems] For example, a material such as a tin-plated steel plate or an aluminum plate is formed into a cup shape by drawing, and then the side walls of this cup-shaped molded product are ironed. consists of doing
DI cans (Drawn) manufactured using the DI molding process.
Ironed Cans) are thinner and lighter than so-called 3-piece cans, which have a soldered body and a bottom lid and a top lid that are rolled into one body.
In addition, there is a large demand for it due to its advantages such as no leakage because there are no seams, and its uses are expected to expand in the future. Conventionally, tin-plated steel sheets and aluminum sheets have been used as materials for DI cans, and demand for tin-plated steel sheets is expected to grow because they are cheaper than aluminum sheets. However, even in tin-plated steel sheets, the amount of tin deposited is usually 2.8~
5.6g/m ² , and due to the recent rise in the cost of electricity and tin, an increase in manufacturing costs is unavoidable, and there is a strong need to develop materials for DI cans that are low cost and have excellent corrosion resistance. On the other hand, in the manufacturing process of DI cans, the ironing process of the cup-shaped material is extremely difficult, and the reduction rate in plate thickness is approximately 70%. The material to be ironed must have excellent lubricity, and tin is effective in providing this lubricity. Therefore, if the amount of tin deposited is reduced in order to reduce manufacturing costs as mentioned above, the ductility effect of the tin layer will deteriorate, resulting in a decrease in lubrication performance and the loss of heat caused by the friction of the material passing through the die during ironing. Seizure or "galling" occurs when the material gets caught in the die. Cans with such seizure or galling have deteriorated corrosion resistance and are no longer usable. Furthermore, if the amount of tin deposited is small, rust is likely to occur after can manufacturing, after degreasing work is performed to remove lubricant and other oils adhering to the can surface, and before moving on to the next process. . On the other hand, DRD cans manufactured using the DRD forming method, which involves forming a circularly punched steel plate through two drawing processes.
Redrawn Can) has problems with corrosion resistance after filling with contents due to cracks that occur in the coating film during molding. As a means to solve the above-mentioned problems, for example,
In JP-A No. 51-63787, a paint containing an epoxyphenol-based, an epoxyurea-formaldehyde-based, a vinyl-based organosol, and a vinyl-based solution resin, or a paint in which an internal lubricant is added to the paint, is used as a material. A method of performing DI molding after partially curing is disclosed.
Furthermore, in Japanese Patent Publication No. 60-4753, after partially curing a surface-treated steel sheet with an epoxyphenol paint or a paint with an organic lubricant added to the paint, DI molding is performed. A method is disclosed. However, since the above-mentioned methods only partially cure the paint, the taste and aroma (hereinafter referred to as "flavor") of the contents of the beverage etc. filled in the can deteriorate, and the color fastness of the paint film deteriorates. It has problems such as bad. Therefore, we have developed a pre-coat paint that does not damage the paint film even when subjected to severe DI molding processing, has excellent lubricity and corrosion resistance, and is inexpensive, and 2 that has a paint film made of such paint on its surface. Although the development of a pre-coated metal plate for piece cans is strongly desired, a pre-coated paint having such characteristics and a pre-coated metal plate for two-piece cans have not yet been proposed. [Object of the Invention] Therefore, the object of the present invention is to provide a paint for pre-coat that is inexpensive, has excellent lubricity and corrosion resistance, and has excellent lubricity and corrosion resistance, without damaging the coating film even when subjected to severe DI or DRD forming processing. and a precoated metal plate for a two-piece can, on at least one surface of which a coating film of such a paint is formed. The present inventors first conducted research on the properties of the uppermost coating film of a steel plate, which contributes to lubrication performance, and found the following. That is, the DI formability in DI forming processing does not improve even if the friction coefficient in the low pressure region is reduced, but is influenced by the lubrication performance in the high pressure region. Therefore, the properties of the coating film on the top layer of the steel plate must be elongation under high pressure, adhesion to the base material, and lubricity of the coating itself. It is necessary to enhance the retention effect of the external lubricant (coolant) that exists between the two, and to fully demonstrate the functions of the external lubricant. As a result of research to obtain a paint that can form a coating film that satisfies the above-mentioned conditions, the present inventors discovered that fluorine atom-substituted olefin polymer-modified hydrocarbon wax particles were added and dispersed as an internal lubricant. It was found that a thermosetting paint made of [Summary of the Invention] This invention was made based on the above findings, and provides a fluorine atom-substituted olefin polymer with a melting point of 70 to 200°C for use as an internal lubricant in a thermosetting paint. Modified hydrocarbon wax particles are
Based on 100 parts by weight of the solid content of the thermosetting paint,
A precoated metal plate for a two-piece can, in which a precoat paint is added in a proportion of 0.1 to 30 parts by weight, and a coating film made of the precoat paint is formed on at least one surface of the metal plate. It has the following characteristics. [Structure of the Invention] In this invention, the thermosetting paint includes a vinyl chloride resin organosol paint blended with a thermosetting resin such as a phenol resin or an epoxy resin, and an epoxy resin and a phenol resin, and an epoxy resin. A can paint made of any one of the following combinations is used: a resin and an amino resin, a polyester resin and an amino resin, an epoxy resin and an acrylic resin, and an epoxy ester resin and an amino resin. The reason for adding fluorine atom-substituted olefin polymer-modified hydrocarbon wax particles as an internal lubricant to the above-mentioned paint is to provide lubricity to the paint film and to improve lubricity during DI forming processing performed under high pressure. This is because the lubrication performance is improved. It is usually used as an internal lubricant to improve the lubrication performance of the paint film and to lower the coefficient of dynamic friction of the paint film. Animal or vegetable lubricants such as beeswax, spermaceti wax, beef tallow, carnauba wax, and lanolin wax, as well as polyethylene wax, do not have sufficient lubrication performance for the coating film during DI molding. Therefore, it is not possible to improve moldability. Furthermore, if a fluorine atom-substituted olefin wax, such as polytetrafluoroethylene wax, is used as an internal lubricant to improve the lubrication performance of the coating film, its melting point is high at 300°C or higher, so it cannot be baked. Since a solid wax remains on the surface of the coated film, extremely unevenness occurs, which is also disadvantageous in terms of cost. Furthermore, since such wax constitutes a coating surface with low surface free energy, it has strong water and oil repellency, which causes problems in painting the inner and outer surfaces of the can after it is molded into the can. Modified hydrocarbon waxes include room-temperature waxes made by modifying hydrocarbon waxes such as low-molecular-weight polyolefins such as polyethylene and polypropylene with polymers of fluorine-substituted olefins such as tetrafluoroethylene, trifluoroethylene, and hexafluoropropylene. Solid wax is used in An example of modification is a method in which particles of a hydrocarbon wax are mixed with fine particles of a fluorine atom-substituted olefin polymer using a powerful mechanical device such as a jet mill. The modified hydrocarbon wax thus obtained becomes wax particles in which a fluorine atom-substituted olefin polymer is bonded to the surface of the hydrocarbon wax particles. Examples of modified hydrocarbon waxes produced by such physical treatments include:
Jiyoji. Examples include polytetrafluoroethylene-modified microcrystalline waxes (trade names: Lanco Wax TF1778, TF1780, etc.) commercially available from M. Langer & Company. The melting point of the above-mentioned modified hydrocarbon wax particles must be within the range of 70°C to 200°C. Here, the melting point of wax particles is the temperature at which wax particles exhibit fluidity without being able to maintain their particle shape. If the melting point is below 70℃, depending on the method of addition to the paint and storage conditions,
It becomes a liquid and separates in the paint, or layer separation occurs in the baked paint film, resulting in insufficient lubrication performance in the high pressure region during DI molding. On the other hand, if the melting point exceeds 200°C, the wax will remain in the baked coating film, resulting in extremely uneven surfaces, as well as the heat generated in the high pressure area during DI molding. Since the wax particles melt and disappear, the coating film cannot maintain sufficient lubricating performance. As an internal lubricant for thermosetting paints,
The addition ratio of the above-mentioned modified hydrocarbon wax particles needs to be 0.1 to 30 parts per 100 parts of the solid content of the paint. If the addition ratio is less than 0.1 part, it will not be possible to provide sufficient lubrication to the coating film during DI molding, resulting in poor moldability, and in the worst case, "galling" will occur during molding. on the other hand,
If the amount added exceeds 30 parts, the thixotropic property becomes strong, causing problems in coating properties, and is also economically disadvantageous. The modified hydrocarbon wax added to the paint preferably has fine particles of 1 to 5 μm. The particle size of the modified hydrocarbon wax is 5 μm.
If the wax is larger than this, the wax will not melt sufficiently during baking and will remain solid in the paint film, resulting in extremely uneven surfaces. Furthermore, problems arise with respect to the dispersion stability of the wax from the viewpoint of the storage stability of the paint. On the other hand, the particle size
Setting the thickness to less than 1 μm increases the cost and is not practical. The pre-coated metal plate on which the paint film described above is formed may be a cold-rolled steel plate without surface treatment, or a surface-treated steel plate plated with tin, nickel, chrome, etc. Alternatively, it may be an aluminum plate. In particular, chrome-plated steel sheets are preferred because they have good coating film adhesion and corrosion resistance. A pre-coated steel sheet, on which at least one surface of the surface-treated steel sheet is coated with a coating film of the present invention to which the above-mentioned modified hydrocarbon wax particles are added, is surface-treated by the coating film. Since the film is protected, the surface treatment film does not come into direct contact with the die during DI molding. Therefore, even after DI molding, the surface treatment film is maintained in a continuous and uniform state. In the pre-coated metal plate of the present invention, the above-mentioned modified hydrocarbon wax particles as an internal lubricant are added to the thermosetting paint on one surface which is to become the outer surface of the can body. A coating film consisting of the precoating paint of the invention is formed, and on the other surface, which is to become the inner surface of the can body, a coating film is formed from the precoating paint in which substantially no internal lubricant is added to the thermosetting paint. It is desirable that a coating film such as this is formed from the viewpoint of improving moldability. The reason is as follows. That is, during the molding process, a coating film is formed on one surface of the can body that is in direct contact with the die and is to become the outer surface of the can body, and a coating film is formed on the other surface that is to be the inner surface of the can body that is held down with a punch. By creating a difference in the lubricity effect under relatively high pressure between the paint film and the paint film, the friction force generated on the side of the paint film that is pressed with the punch, that is, the side that becomes the inner surface of the can body. It is presumed that this difference substantially contributes to improving moldability. Furthermore, as mentioned above, there are economic advantages to using a coating material to which no internal lubricant is added as a coating material for the coating film formed on the other surface, which is to become the inner surface of the can body. can get. For molded cans obtained by DI molding, if the filling inside the can is dry matter or a liquid with weak properties that corrode the can, the coating film remains uniformly even after the molding process. It is not necessary to apply a top coat.
However, if the can is filled with a liquid that has a strong tendency to corrode the can or a flavor is important, it is recommended to apply a top coat. As described above, the pre-coated steel sheet of the present invention does not require top coating depending on the filling in the can, so in this case, the process for top coating during can manufacturing can be reduced, making it extremely economical. be. The precoat paint of the present invention can be applied to the surface of a steel plate by a known coating method such as roll coating, spray coating, dip coating, curtain flow coating, or the like. Usually, a reverse roll coater is used to coat a coil-shaped steel plate, and a natural roll coater is used to coat a sheet-shaped steel plate. Baking of the paint applied in this way is
This is done by heating with hot air at 150 to 400°C for about 10 seconds to 10 minutes. Note that the baking may be performed by infrared heating, high frequency induction heating, etc. alone or in combination, and by such means, baking can be performed in an even shorter time. The thickness of the coating layer formed on the surface of the steel plate is preferably within the range of 1 to 10 μm on one side. That is, if the thickness is less than 1 μm, the coating film will break during DI molding, making it difficult to maintain the continuity of the coating film, resulting in poor moldability, and in the worst case, "galling" will occur. On the other hand, if the thickness exceeds 10 μm, a build-up phenomenon tends to occur in the coating film during molding, which is unfavorable from an economic standpoint. In the case of double-sided coating, the amount of coating on the front and back sides may be the same or different. In addition, in the DI molding process, the material is formed into a cup shape by drawing, and then
This is done by stretching the side wall portion by ironing and forming it into a predetermined shape. After the DI molding process, a top coat may be applied using a known paint such as vinyl or epoxy-acrylic paint depending on the material to be filled. Further, if necessary, the outer surface may be subjected to a finishing process such as white coating with white paint, printing, finishing coating, etc. In addition, if white paint is added in advance to the paint for the coating film formed on one surface of the can body, it can be done without or with a slight finishing process as described above. It can be painted white depending on the method. [Examples of the Invention] Next, the present invention will be explained in further detail with reference to Examples. As pre-coating paints of the present invention, the following present invention paints A-1 to E and the following comparative paints F to J, which are outside the scope of the present invention, were prepared for comparison. Example Paint of the present invention A-1 (vinyl chloride resin organosol paint) Thermosetting paint Vinyl chloride paste resin: Trade name. Sumiritz EX-13 (manufactured by Sumitomo Chemical Co., Ltd.)...45 parts (parts by weight, same hereinafter) Phenol resin: Product name. Hytanol 4020 (manufactured by Hitachi Chemical Co., Ltd.)...10 parts Polyester plasticizer: Product name. Polysizer P-202 (manufactured by Dainippon Ink Chemical Co., Ltd.)...
20 parts Oil-free alkyd resin: Product name. Almatex P-646 (manufactured by Mitsui Toatsu Co., Ltd.)...
25 parts Teflon-modified polyethylene wax: Product name. Lancowax TF1778 Melting point: 100°~
110℃ (manufactured by George M. Langer & Company)...20 parts per 100 parts of thermosetting paint solid content Organotin stabilizer...1.6 parts per 100 parts of vinyl chloride resin The above phenolic resins, plasticizers, oils Free alkyd resin and stabilizer, xylene: 40%
(weight%, same below), cellosolve acetate: 30
%, diisobutyl ketone: After dissolving in a mixed solvent consisting of 30%, vinyl chloride paste resin and Teflon-modified polyethylene wax were added and dispersed while stirring at high speed. .4) A vinyl chloride resin-based organosol paint (paint A-1 of the present invention) was prepared. Paint A-2 of the present invention (vinyl chloride resin organosol paint) In the paint A-1 of the present invention described above, the addition amount of the Teflon-modified polyethylene wax was 10 parts per 100 parts of the solid content of the thermosetting paint. A vinyl chloride resin organosol paint (paint A-2 of the present invention) having the same components as the paint A-1 of the present invention was prepared. Paint of the present invention A-3 (vinyl chloride resin organosol paint) In the paint of the present invention A-1 described above, the addition amount of the Teflon-modified polyethylene wax was 5 parts per 100 parts of the solid content of the thermosetting paint. A vinyl chloride resin-based organosol paint (paint A-3 of the present invention) having the same components as the paint A-1 of the present invention was prepared. Paint of the present invention B (vinyl chloride resin organosol paint) Thermosetting paint Vinyl chloride paste resin: Product name. Sumiritz EX-13 (manufactured by Sumitomo Chemical Co., Ltd.)...40 parts Phenol resin: Product name. Hytanol 4020 (manufactured by Hitachi Chemical Co., Ltd.)...16 parts Vinyl chloride/vinyl acetate/maleic acid copolymer: Product name. Vinyrite VMCC (manufactured by Union Carbide)...40 parts Bisphenol A type epoxy resin: Product name. Epicoat 828 (manufactured by Yuka Ciel Epoxy Co., Ltd.)...4 parts Teflon-modified polyethylene wax: Product name. Rankowacs TF1778 (Jiyoji.M.
(manufactured by Langer & Company)...20 parts per 100 parts of paint solid content, the above phenolic resin, vinyl chloride/vinyl acetate/maleic acid copolymer, and epoxy resin,
Xylene: 40%, cellosolve acetate: 30%,
After dissolving in a mixed solvent consisting of 30% diisobutyl ketone, vinyl chloride paste resin and Teflon-modified polyethylene wax were added and dispersed while stirring at high speed. ) was prepared as a vinyl chloride resin organosol paint (paint B of the present invention). Invention paint C (epoxyphenol paint) Thermosetting paint Bisphenol A type epoxy resin: Product name. Epicote 1009 (manufactured by Yuka Ciel Epoxy Co., Ltd.)...80 parts Phenol resin: Product name. Hytanol 4020 (manufactured by Hitachi Chemical Co., Ltd.)...20 parts Teflon-modified polyethylene wax: Product name. Rankowacs TF1778 (Jiyoji.M.
(manufactured by Langer & Company)...20 parts per 100 parts of paint solid content The above bisphenol A type epoxy resin and phenol resin are composed of xylene: 12%, cellosolve acetate: 55%, N-butanol 10%, and cyclohexane: 23%. After dissolving in a mixed solvent, Teflon polyethylene wax was added and dispersed while stirring at high speed, solid content approximately 30%, viscosity 70 seconds (25°C food cup No. 4), epoxy phenol resin paint (paint C of the present invention). was prepared. Paint of the present invention D (epoxy amino paint) Thermosetting paint Bisphenol A type epoxy resin: Product name. Epicoat 1007 (manufactured by Yuka Ciel Epoxy Co., Ltd.)...90 parts Urea formaldehyde resin: Product name. Meran
11E (manufactured by Hitachi Chemical Co., Ltd.)...10 parts Teflon-modified polyethylene wax: Product name. Rankowacs TF1778 (Jiyoji.M.
(manufactured by Langer & Company)... 20 parts per 100 parts of paint solid content The above bisphenol A type epoxy resin and urea formaldehyde resin are mixed with diacetone alcohol.
After dissolving in a mixed solvent consisting of DAA: 15%, methyl isobutyl carbyl: 7%, and ethyl cellosolve: 78%, Teflon-modified polyethylene wax was added and dispersed while stirring at high speed.
Solid content approximately 30%, viscosity 50 seconds (25℃ food cup No.
4) The epoxy amino resin paint (paint D of the present invention) was prepared. Invention paint E (polyester amino paint) Thermosetting paint Polyester resin: Product name. Byron RV560
(manufactured by Toyobo Co., Ltd.)...70 parts Benzoguanamine resin: Product name. Melan 366 (manufactured by Hitachi Chemical Co., Ltd.)...25 parts Bisphenol A type epoxy resin: Product name. Epicoat 828 (manufactured by Yuka Ciel Epoxy Co., Ltd.)...5 parts Teflon-modified polyethylene wax: Product name. Rankowacs TF1778 (Jiyoji.M.
(manufactured by Langer & Co.)...20 parts per 100 parts of paint solid content After dissolving the above polyester resin, benzoguanamine resin and bisphenol A type epoxy resin in a mixed solvent consisting of 50% xylene and 50% cellosolve acetate, Teflon A modified polyethylene wax was added and dispersed while stirring at high speed to prepare a polyester amino resin paint (paint E of the present invention) having a solid content of about 30% and a viscosity of 40 seconds (Food Cup No. 4 at 25°C). Comparative Example Comparative Paint F (Vinyl chloride resin organosol paint) In the paint A-1 of the present invention described above, instead of the Teflon-modified polyethylene wax,
Polytetrafluoroethylene wax (Lubloon L-5 manufactured by Daikin Industries, Ltd.) at 326°C was heated at 20°C.
A vinyl chloride resin-based organosol paint (comparative paint F) was prepared having the same components as the paint A-1 of the present invention, except that a portion of the paint A-1 was used. Comparative paint G (vinyl chloride resin organosol paint) In the above-mentioned present invention paint A-1, instead of the Teflon-modified polyethylene wax, a wax with a melting point of 65
Microcrystalline wax at °C (Ultra Flex Amber manufactured by Toyo Petrolite Co., Ltd.)
A vinyl chloride resin-based organosol paint (comparative paint G) was prepared having the same components as the paint A-1 of the present invention, except that 20 parts of the same were used. Comparative paint H (vinyl chloride resin organosol paint) The present invention paint A-1 described above except that 20 parts of lanolin (hard lanolin manufactured by Yoshikawa Oil Co., Ltd.) was used instead of the Teflon-modified polyethylene wax. Vinyl chloride resin organosol paint with the same components as paint A-1 (comparative paint H)
was prepared. Comparative paint I (epoxyphenol paint) An epoxyphenol paint (comparative paint I) was prepared which had the same components as the paint C of the present invention described above except for the Teflon-modified polyethylene wax. Comparative paint J (vinyl chloride resin-based organosol paint) A vinyl chloride resin-based organosol paint (comparison) with the same components as the present invention paint A-1, except that the Teflon-modified polyethylene wax was removed from the above-mentioned present invention paint A-1. Paint J) was prepared. Surface-treated steel plates shown in (a) and (b) below were prepared as metal plates for coating with the above-described present invention paints A-1 to E and comparative paints F to J. (b) After cleaning both surfaces of a low carbon cold rolled steel plate with a thickness of 0.3 mm by ordinary electrolytic degreasing and electrolytic pickling, a
CrO ₃ and a 2.0 g/NH ₄ F aqueous solution were electrolyzed for 1 second at a liquid temperature of 50°C and a current density of 30 ASD to form a metallic chromium layer of 50 mg/m ² on each of both surfaces of the steel plate and 15 mg of metal chromium on the top surface. / ^m2 of chromium hydrated oxide layer was formed. (b) After cleaning both surfaces of the same cold-rolled steel sheet as in (a) above by normal electrolytic degreasing and electrolytic pickling, the steel plate was used as a cathode to clean the surfaces in a normal ferrostan plating bath (Sn ²⁺ : 30g/, free acid: 15g/ in terms of sulfuric acid, ENSA: 5g/), the liquid temperature
Electrolysis was carried out for 1 second at 40° C. and a current density of 6 ASD to form a metal tin plating layer of 0.34 g/m ² on each of both surfaces of the steel plate. Next, using this tin-plated steel plate as a cathode, in a 30 g/a CrO ₃ aqueous solution,
Electrolyze for 1 second at a liquid temperature of 50℃ and a current density of 30ASD.
A 15 mg/m ² chromium hydrated oxide layer was formed on the top surface of the metal tin plating layer. The above-mentioned present invention paints A-1 to E and comparative paints F to J, the above-mentioned surface-treated steel sheets (a) and (b), and the cold-rolled steel sheet without surface treatment were mixed as shown in Table 1 below. In combination, pre-coated steel plates of Examples 1 to 12 and pre-coated steel plates of Comparative Examples 1 to 4 were prepared. The pre-coated steel plate was prepared by coating both sides of the steel plate with the inventive coating or the comparative coating to a thickness of 5 μm using a roll coater, and then baking it in a box oven at a temperature of 205°C for 10 minutes. I did it.

【表】このようにして調製された実施例１〜12および
比較例１〜４のプレコート鋼板の各々について、
DI成形加工性、缶外面側の塗膜被覆率、ストリ
ツピング性および耐食性（耐U.C.C性、耐F.F.C
性及びIPV値）を、以下に述べる性能試験によつ
て評価し、その結果を第２表に示した。 (1) DI成形性試験 DI成形は、まず123mmφのブランクを打抜
き、市販のカツピングプレスで、内径：72mm
φ、高さ：36mmのカツプを成形し、次いでこの
カツプを市販のDIマシンに装入して、ポンチ
スピード：30ｍ／分、ポンチストローク600mm
で、リドロウ加工及び３段階でアイアニング加
工（それぞれのリダクシヨン30％、28％、24
％）を行ない、最終的に缶内径52.0mm、缶高さ
130mmの缶を成形した。なお、DI成形中には、
市販のクーラント（５％）を通常〜100℃の温
度で循環的に塗布した。また、DI成形性の評価については、DIマシ
ンのポンチ部に取り付けられたロードセルから
成形荷重を検出し、ポンチストロークから、成
形エネルギーを算出した。次に成形エネルギー
の計算式を示す。Ｅ＝∫_sP.g.d_s （Ｅ：成形エネルギー、ｓ：ストローク、Ｐ：成形荷重、ｇ：重力加速度）評価は各段階のトータル成形エネルギーとし
て成形エネルギーが小さいものを、DI成形性
が優れていると評価した。 (2) 缶外面の塗膜被覆率上記(1)のDI成形性試験において、成形され
た缶体外面の塗膜被覆率を、缶体にトレース方
眼紙を巻き、塗膜被覆部分の升目を計算し、百
分率で評価した。 (3) ストリツピング性上記(1)のDI成形性試験において、成形され
た缶体からポンチが引抜かれる際に、缶体の頭
部がストリツパーにひつかかり、缶の高さが低
くなる現象を缶の高さで評価した。 (4) 耐食性試験前述した成形方法で作られた試験片に対し、
市販の脱脂液（PH8.5、濃度：２％）を液温50
℃で２分間スプレーし、DI成形時に、缶に塗
布されたクーラントを除去した。次いで、ビニ
ライトVMCH（U.C.C社塩化ビニル・酢酸ビニ
ル・マレイン酸共重合体）の20％溶液（溶剤：
メチルエチルケトン／キシレン＝１／１の混合
溶剤）を、１缶当り250mgスプレー塗装した後、
205℃で３分間焼付けて、缶内面にトツプコー
トを形成した上、下記の試験を行なつた。ａ U.C.C試験缶内面部を50×70mmのサイズに切り出し、素
地まで達するクロスカツトを入れ、裏面部およ
びエツジ部をシールして、38℃に維持された腐
食液（1.5％クエン酸、1.5％塩化ナトリウム）
中に96時間浸漬した後、テープを張りつけ次い
でこれを剥離し、このときの腐食幅および塗膜
剥離状況で評価した。評価基準は次の通りであ
る。 ◎非常に優れる〇優れる △やや劣る ×劣
るｂ F.F.C試験缶外面部を50×70mmのサイズに切り出し、素
地まで達するクロスカツトを入れ、裏面部およ
びエツジ部をシールして、35℃の塩水による塩
水噴霧試験を１時間行ない、次いで流水で軽く
洗浄後、温度25℃、相対湿度85％の恒温恒湿室
中で、５週間暴露し、発生した糸状腐食の幅お
よび長さで評価した。評価基準は次の通りであ
る。 ◎非常に優れる〇優れる △やや劣る ×劣
るｃ I.P.V試験缶サンプル内部に、ペプシコーラ（日本ペプ
シコーラ）を１缶当り250c.c.充填し、液温38℃
で６ケ月間保持し、内容物中に溶出したFeイ
オンの量を原子吸光法を用いて定量し、Feイ
オン溶出量（ppm）の多少で評価した。第２表から明らかなように、塗料中に、内部
潤滑剤としての、フツ素原子置換オレフインに
より変性された炭化水素系ワツクスが添加され
ていない比較例No.１〜４は、いずれも成形エネ
ルギーが高いため、DI成形加工性が悪く、最
悪の場合はDI成形加工時に塗膜が剥離したり、
“かじり”が発生した。[Table] For each of the prepainted steel sheets of Examples 1 to 12 and Comparative Examples 1 to 4 prepared in this way,
DI molding processability, coating film coverage on the outer surface of the can, stripping property, and corrosion resistance (UCC resistance, FFC resistance)
performance and IPV value) were evaluated by the performance test described below, and the results are shown in Table 2. (1) DI moldability test For DI molding, first punch out a 123mmφ blank, and use a commercially available cutting press to cut the inner diameter to 72mm.
Form a cup with φ, height: 36 mm, then load this cup into a commercially available DI machine, punch speed: 30 m/min, punch stroke 600 mm.
Then, redraw processing and ironing processing were performed in three stages (reductions of 30%, 28%, and 24%, respectively).
%), and finally the inner diameter of the can is 52.0mm and the height of the can is 52.0mm.
A 130mm can was molded. In addition, during DI molding,
A commercially available coolant (5%) was applied cyclically at a temperature of typically ~100°C. Furthermore, regarding the evaluation of DI formability, the forming load was detected from a load cell attached to the punch section of the DI machine, and the forming energy was calculated from the punch stroke. The formula for calculating forming energy is shown below. E=∫ _s Pgd _s (E: forming energy, s: stroke, P: forming load, g: gravitational acceleration) The evaluation is based on the total forming energy at each stage, and those with small forming energy are considered to have excellent DI formability. evaluated. (2) Paint film coverage on the outside surface of the can In the DI moldability test in (1) above, the paint film coverage on the outside surface of the molded can was measured by wrapping tracing graph paper around the can and measuring the squares of the paint film covered area. calculated and evaluated as a percentage. (3) Stripping property In the DI formability test mentioned in (1) above, when the punch is pulled out of the formed can body, the head of the can body gets caught on the stripper, reducing the height of the can. It was evaluated based on the height of (4) Corrosion resistance test For test pieces made by the above-mentioned molding method,
Commercially available degreasing liquid (PH8.5, concentration: 2%) at a temperature of 50
The coolant applied to the can during DI molding was removed by spraying at ℃ for 2 minutes. Next, a 20% solution (solvent:
After spraying 250mg of methyl ethyl ketone/xylene (1/1 mixed solvent) per can,
After baking at 205°C for 3 minutes to form a top coat on the inner surface of the can, the following tests were conducted. a UCC test Cut the inner surface of the can into a size of 50 x 70 mm, insert a cross cut that reaches the substrate, seal the back surface and edges, and add a corrosive solution (1.5% citric acid, 1.5% sodium chloride) maintained at 38°C. )
After being immersed in the water for 96 hours, a tape was applied and then peeled off, and evaluation was made based on the corrosion width and the degree of paint film peeling. The evaluation criteria are as follows. ◎Excellent 〇Excellent △Slightly inferior ×Poorb FFC test Cut the outer surface of the can into a size of 50 x 70 mm, insert a cross cut that reaches the base material, seal the back surface and edges, and salt water spray with 35℃ salt water. The test was carried out for 1 hour, and then after being lightly washed with running water, the specimens were exposed for 5 weeks in a constant temperature and humidity chamber at a temperature of 25° C. and a relative humidity of 85%, and the width and length of the filamentous corrosion that occurred was evaluated. The evaluation criteria are as follows. ◎Excellent 〇Excellent △Slightly inferior ×Poorc IPV test 250 c.c. of Pepsi Cola (Japan Pepsi Cola) was filled into each can sample, and the liquid temperature was 38°C.
The content was kept for 6 months, and the amount of Fe ions eluted into the contents was quantified using atomic absorption spectrometry, and the amount of Fe ions eluted (ppm) was evaluated. As is clear from Table 2, Comparative Examples Nos. 1 to 4, in which a hydrocarbon wax modified with a fluorine atom-substituted olefin as an internal lubricant was not added to the paint, had a molding energy of DI molding processability is poor due to the high
“Galling” occurred.

〔Effect of the invention〕

以上述べたように、この発明によれば、熱硬化
性塗料中に、フツ素原子置換オレフイン系重合体
変性炭化水素系ワツクス粒子が添加されており、
このような塗料により、金属板の表面に塗膜が形
成されているので、厳しいDI成形加工が施され
ても塗膜が損傷せず、優れた潤滑性および耐食性
が得られ、しかも安価であるから経済的であり、
DRD缶の場合には、より優れた耐食性が得られ
る等、工業上多くの優れた効果がもたらされる。 As described above, according to the present invention, fluorine atom-substituted olefin polymer-modified hydrocarbon wax particles are added to the thermosetting paint,
These paints form a coating film on the surface of the metal plate, so even when subjected to severe DI forming processing, the coating film will not be damaged, providing excellent lubricity and corrosion resistance, and is inexpensive. It is economical from
In the case of DRD cans, many excellent industrial effects are brought about, such as better corrosion resistance.

Claims

[Scope of Claims] 1. Fluorine atom-substituted olefin polymer-modified hydrocarbon wax particles having a melting point of 70 to 200°C are used as an internal lubricant in a thermosetting paint. 0.1 to 30 per 100 parts by weight of solid content
A pre-coat paint characterized by being added in parts by weight. 2. The precoating paint according to claim 1, wherein the thermosetting paint is made of a vinyl chloride resin blended with a thermosetting resin. 3. The thermosetting paint is a combination of an epoxy resin and a phenol resin, an epoxy resin and an amino resin, a polyester resin and an amino resin, an epoxy resin and an acrylic resin, and an epoxy ester resin and an amino resin. The precoat paint according to claim 1, characterized in that it is made of any one of the above. 4 Fluorine atom-substituted olefin polymer-modified hydrocarbon wax particles with a melting point of 70 to 200°C are added to the thermosetting paint as an internal lubricant to 100 parts by weight of the solid content of the thermosetting paint. vs. 0.1 to 30
2, characterized in that a coating film is formed on at least one surface thereof by applying and baking a precoating paint, which is added in the proportion of parts by weight.
Pre-painted metal plate for peace cans. 5. The precoated metal plate for a two-piece can according to claim 4, wherein the thermosetting paint is made of a vinyl chloride resin blended with a thermosetting resin. 6. The thermosetting paint is a combination of an epoxy resin and a phenol resin, an epoxy resin and an amino resin, a polyester resin and an amino resin, an epoxy resin and an acrylic resin, and an epoxy ester resin and an amino resin. The precoated metal plate for a two-piece can according to claim 4, characterized in that it is made of any one of the following. 7. The precoated metal plate for two-piece cans according to claim 4, wherein the coating film made of the precoating paint has a thickness of 1 to 10 μm per side. 8 Fluorine atom-substituted olefin polymer-modified hydrocarbon wax particles with a melting point of 70 to 200°C are added to the thermosetting paint as an internal lubricant to 100 parts by weight of the solid content of the thermosetting paint. vs. 0.1 to 30
A coating film is formed by applying and baking a pre-coat paint, which is added in parts by weight, on one surface of the can body which is to become the outer surface, and substantially internally is added to the thermosetting paint. A precoated metal plate for a two-piece can, characterized in that a coating film obtained by applying and baking a precoating paint to which no lubricant is added is formed on the other surface that is to become the inner surface of the can body. 9. A patent characterized in that the thermosetting paint of the coating film formed on one surface which is to become the outer surface of the can body is made of a vinyl chloride resin blended with a thermosetting resin. A precoated metal plate for two-piece cans according to claim 8. 10 The thermosetting paint of the coating film formed on the other surface that should become the inner surface of the can body is a vinyl chloride resin blended with a thermosetting resin, an epoxy resin and a phenol resin, an epoxy resin. and an amino resin, a polyester resin and an amino resin, an epoxy resin and an acrylic resin, and an epoxy ester resin and an amino resin. A pre-coated metal plate for two-piece cans as described in . 11. The precoated metal plate for two-piece cans according to claim 8, wherein the coating film made of the precoating paint has a thickness of 1 to 10 μm per side.