JPH0317550B2 - - Google Patents
Info
- Publication number
- JPH0317550B2 JPH0317550B2 JP15241787A JP15241787A JPH0317550B2 JP H0317550 B2 JPH0317550 B2 JP H0317550B2 JP 15241787 A JP15241787 A JP 15241787A JP 15241787 A JP15241787 A JP 15241787A JP H0317550 B2 JPH0317550 B2 JP H0317550B2
- Authority
- JP
- Japan
- Prior art keywords
- coating
- roller
- bottom radius
- seamless
- coating film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000000576 coating method Methods 0.000 claims description 65
- 239000011248 coating agent Substances 0.000 claims description 59
- 238000000034 method Methods 0.000 claims description 13
- 239000011253 protective coating Substances 0.000 claims description 13
- 229920001971 elastomer Polymers 0.000 claims description 8
- 239000005060 rubber Substances 0.000 claims description 8
- 239000003973 paint Substances 0.000 description 25
- 230000007547 defect Effects 0.000 description 8
- 238000010422 painting Methods 0.000 description 8
- 239000004593 Epoxy Substances 0.000 description 4
- 238000007664 blowing Methods 0.000 description 4
- 239000007769 metal material Substances 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005187 foaming Methods 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000010409 ironing Methods 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 238000007761 roller coating Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229920000181 Ethylene propylene rubber Polymers 0.000 description 1
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- 229920000459 Nitrile rubber Polymers 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- 229920000800 acrylic rubber Polymers 0.000 description 1
- -1 aluminum Chemical class 0.000 description 1
- 239000002519 antifouling agent Substances 0.000 description 1
- 235000013405 beer Nutrition 0.000 description 1
- 229920005549 butyl rubber Polymers 0.000 description 1
- 235000014171 carbonated beverage Nutrition 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000011651 chromium Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- 210000003298 dental enamel Anatomy 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000005429 filling process Methods 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 239000004922 lacquer Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229920001084 poly(chloroprene) Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 229920001195 polyisoprene Polymers 0.000 description 1
- 229920003225 polyurethane elastomer Polymers 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 239000005028 tinplate Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Application Of Or Painting With Fluid Materials (AREA)
- Rigid Containers With Two Or More Constituent Elements (AREA)
- Details Of Rigid Or Semi-Rigid Containers (AREA)
Description
（産業上の利用分野）
本発明はシームレス罐の塗装方法に関するもの
で、より詳細にはシームレス罐の罐底ラジアス部
に塗膜欠陥がなくしかも十分な厚みを有する外面
保護塗膜を形成させる方法に関する。
（従来の技術）
金属素材の絞り−しごき加工で形成されるシー
ムレス罐は、炭酸飲料やビール等の自生圧力を有
する内容物を収容させる耐圧罐として広く使用さ
れている。この耐圧罐では、内圧により罐底部が
外方に突出する所謂バツクリングを防止するた
め、罐底部に内方向きのドーム部を形成すると共
に、この罐底ドーム部と罐胴部とを、外方に突出
した罐底ラジアス部を介して接続させる構造を一
般に採用している。
このシームレス罐では、成形前の金属素材に予
じめ印刷塗装を行うことは工業的に未だ成功する
に至つていなく、従つて成形後の個々の罐体に塗
装を行わなければならない。この種のシームレス
罐体において、塗装上最も重要な点は、罐底ラジ
アス部の塗装であり、この罐底ラジアス部は、移
送及び保存時に支持面と接触することから、この
部分に非塗装部分或いは塗膜欠陥が存在すると、
製罐工程或いは内容物充填工程における罐底部の
滑り不良による移送トラブルが発生したり、或い
は付着水滴の影響による腐食が発生することにな
る。
罐底ラジアス部に有効に保護塗膜を形成する方
法として、特公昭58−5712号公報には、罐底ラジ
アス部を塗布ローラと接触させて罐底ラジアス部
の外面に保護塗装を行うことが記載されている。
（発明が解決しようとする問題点）
上記先行技術は、罐底ラジアス部への保護塗装
を行う手段を提供したものとして意義深いもので
あるが、形成される塗膜の品質に関して未だ問題
があることがわかつた。即ち、従来の罐底ラジア
ス部の塗装状態を拡大して示す第１図において、
罐底ラジアス部４に形成される保護塗膜６は、罐
底ラジアス部４の稜線７の位置において最も薄
く、その両側では厚くなる傾向があり、最も被覆
（カバレツジ）の要求される稜線７の部分で膜厚
が薄くなり或いは塗料抜け（無塗料部）を生じる
という欠点がある。
また、塗布ローラによる罐底ラジアス部の塗装
に際し、塗料の塗布厚を増大させることにより、
上記欠点を解消しようとする場合には、塗料中に
まき込まれた空気が焼付工程で塗膜の発泡を生じ
る傾向があり、やはり塗膜欠点のない保護塗膜を
形成することが困難となる。
従つて、本発明の目的は、罐底ラジアス部を塗
装ローラと接触させて罐底ラジアス部外面に保護
塗膜を形成させる場合に生じる前記欠点を解消
し、罐底ラジアス部、特にその稜線の部分に塗膜
欠点がなくしかも十分な厚みを有する外面保護塗
膜を確実に形成するための改良方法を提供するに
ある。
（問題点を解決するための手段）
本発明によれば、内方向きに突出した罐底ドー
ム部と罐胴部とが外方に突出した罐底ラジアス部
を介して一体化されているシームレス罐の罐底ラ
ジアス部を塗布ローラと接触させて、罐底ラジア
ス部の外面に保護塗装を行なうシームレス罐の塗
装方法において、罐底ラジアス部を第一の塗布ロ
ーラと接触させて罐底ラジアス部の外面に第一の
塗膜を形成させ、第一の塗布ローラとの接触が解
除された後シームレス罐に対して罐底ラジアス側
から空気を吹付け、次いで罐底ラジアス部を第二
の塗布ローラと接触させて罐底ラジアス部の第一
の塗膜上に第二の塗膜を形成させることを特徴と
するシームレス罐の塗装方法が提供される。
（作用）
本発明では、塗布ローラとの接触による罐底ラ
ジアス部へのローラ塗布を二段にわたつて行なう
が、この二段のローラ塗布の間に罐底ラジアス側
からの空気吹付けを行うことが顕著な特徴であ
る。
本発明者等は、第一段のローラ塗布に続いて、
第一の塗布ローラとの接触が解除された後のシー
ムレス罐に対して、罐底ラジアス側から空気を吹
付けると、罐底ラジアス部、特にその稜線の部分
に塗膜欠点がなく、しかも十分な厚みを有する外
面保護塗膜を確実に形成させ得ることを見出し
た。
即ち、先ず第一段のローラ塗布により形成され
た罐底ラジアス部上に形成された第一の塗膜に対
して空気を吹付けることにより、塗膜表面の溶剤
が急速に揮散され、これにより塗膜のセツテイン
グ、即ち固定化が極めて短時間の間に生じる。か
くして、第一段の塗布ローラで形成される塗膜６
が第１図に示す通り、罐底ラジアス部の稜線７の
位置で薄肉化され、或いは未塗装部が部分的に存
在したとしても、第２図に示す通り、このセツテ
イングされた第一の塗膜６の上に、第二段の塗布
ローラにより、第二の塗膜８が有効に形成され、
全体として塗膜欠点がなくしかも十分な厚みの保
護塗膜を罐底ラジアスに対して十分な巾で、しか
もその稜線部を完全に覆うように施こすことがで
きる。しかも、この二段塗布による塗膜は塗膜の
発泡を生ずることがなく、被覆の完全さにおいて
も優れている。
二段のローラ塗布を行うが、後に塗膜のセツテ
イング操作を行わない場合は、形成される膜厚に
はバラツキが大きく、本方法のように十分に厚
く、しかもバラツキの少ない塗膜を形成すること
が困難となる。
第一段のローラ塗布後に行う空気吹付けは、罐
底ラジアス部全周へ塗膜を均一且つ一様に施こす
上で、別の好ましい作用を行なう。即ち、第一段
の塗布ローラから排出されるシームレス罐は、シ
ームレス罐の支持搬送面に対して垂直ではなく、
或る偏よりを持つ場合や支持用ピンから幾分抜け
ている場合が屡々認められる。シームレス罐がこ
のように偏よつた状態や抜けかかつた状態で第二
の塗布ローラに供給されると、第二の塗膜を罐底
ラジアス部の全周にわたつて一様な厚みに施こす
ことが困難となる。これに対して、本方法によれ
ば、第一段の塗布ローラから解除されるシームレ
ス罐に罐底ラジアス部から空気を吹付けることに
より、シームレス罐を支持用ピン側に押付けて、
このピンを深く挿入させ且つこの罐を支持搬送面
に対して垂直に位置させ、第二段の塗布ローラに
よる塗装を正しく位置決めされた状態で、確実に
行わせることが可能となる。
（実施例）
本発明の塗装に用いるシームレス罐を示す第３
図において、このシームレス罐１０は、使用した
金属素材とほぼ同じ厚さを有する罐底部２と、絞
りしごき加工により薄肉化された罐胴部１とから
成つている。罐底部２の中央部分は内方に滑らか
に突出されたドーム部３を形成しており、このド
ーム部３と罐胴部１とは、外方向きに突出したリ
ング状の罐底ラジアス部４を介して接続されてい
る。
第３図に示す罐底ラジアス部４はテーパー部
（チヤイム部）５よりも外方に突出しているが、
テーパー部よりも外方に突出していなくてもよい
のは勿論である。
本発明の塗装工程を説明するための第４図にお
いて、罐胴外面に対して塗装印刷が行われた後又
は塗装印刷前のシームレス罐１０は、チエンコン
ベア１１のピン１２に支持され、罐底ラジアス部
塗装域１３に導入される。この塗装域１３には、
チエンコンベア１１の移動方向に延びている駆動
エンドレスベルト１４が配置され、チエンコンベ
ア１１と同期した速度で駆動される。
塗装域１３には、塗料１５を収容するタンク１
６と、塗料中に部分的に浸漬されている汲み上げ
ローラ１７と、汲み上げローラ１７と接触し、回
転する転送ローラ１８と、転送ローラ１８と接触
し回転する第一の塗布ローラ１９及び第二の塗布
ローラ２０とから成る塗布機構が配置される。第
一の塗布ローラ１９と第二の塗布ローラ２０とは
互いに離されていて、転送ローラ１８に対して異
なつた位置で接触している。第一及び第二の塗布
ローラ１９，２０はその表面に周状のゴム層２１
を備えており、これらのゴム層２１とエンドレス
ベルト１４との間隔は、その間に入るシームレス
罐１０に対して、一定の接触圧（塗布圧）がゴム
層２１により与えられるようなものである。
第一の塗布ローラ１９と第二の塗布ローラ２０
との間には、空気吹出口２２がエンドレスベルト
１４と対向するようにエアノズル２３が設けられ
ている。
タンク１６内の塗料１５は、汲み上げローラ１
７の回転に伴ないローラ表面に汲み上げられ、転
送ローラ１８を経て第一の塗布ローラ１９及び第
二の塗布ローラ２０の表面に供給される。
先ず、ピン１２及びエンドレスベルト１４に支
持されて搬送されるシームレス罐１０の罐底ラジ
アス部４は、第一の塗布ローラ１９と接触して、
ローラ表面の塗料がこれに施される。第一の塗布
ローラ１９から排出されるシームレス罐１０ａ
は、次いでエアノズル２３からの空気を吹付けら
れ、第一の塗膜のセツテイングと、シームレス罐
１０ａの正しい位置決めとが行われる。次いでこ
のシームレス罐１０ａは第二の塗布ローラ２０と
接触して、ローラ表面の塗料が罐底ラジアス部に
更に施され、罐底ラジアス部の完全に塗装された
シームレス罐１０ｂとなる。
塗装済シームレス罐１０ｂは、図示していない
が、それ自体公知のオーブン等の塗膜焼付装置に
送られて、塗膜の焼付が行われる。
本発明は、種々のシームレス罐に適用できる。
罐を構成する金属素材は、アルミニウムの如き軽
金属の他に、ブリキ、亜鉛メツキ鋼板、クロム処
理鋼板、或いはブラツク・プレート（未処理鋼
板）から成つていることができ、これら何れの素
材の場合にも、罐底部からの腐食を有効に防止す
ることができる。
保護塗料としては、耐腐食性の点で熱硬化性塗
料、特に変性エポキシ系塗料、フエノール・エポ
キシ塗料、アミノ−エポキシ塗料、ビニル変性エ
ポキシ塗料等が使用されるが、本発明に使用し得
る塗料は勿論これに限定されない。これらのベー
ス樹脂はエナメル或いはラツカー等の有機溶剤溶
液の形で前述した手段により施される。用いる塗
料は一般に40乃至90秒、特に50乃至70秒のフオー
ドカツプ粘度を有することが望ましい。
塗膜の厚み（乾燥基準）は、第一段で４乃至
10μｍ、特に６乃至8μｍの範囲が適当であり、全
体としては７乃至13μｍ、特に９乃至11μｍの範
囲が適当である。
塗布ローラ表面のゴム層は、一般に７乃至15゜、
特に８乃至10°の硬度（JIS Ｋ 6301スプリング
式硬さ試験機Ｃタイプでの測定値）と、25乃至45
mm、特に35乃至40mmの厚みとを有するのがよい。
罐へのローラ圧は、ニツプ巾（罐底ラジアス部
への塗布巾）が２乃至3.5mm、特に2.5乃至3.0mmの
巾となるようなものがよい。ゴムとしては、上記
条件を満足し且つ耐油性、耐油剤性を有するもの
であれば任意のものでよく、例えばポリイソプレ
ンゴム、SBR、NBR、ブチルゴム、クロロプレ
ンゴム、ブタジエンゴム、エチレン−プロピレン
ゴム、ポリウレタンゴム、アクリルゴム等が使用
される。
空気吹付に用いる空気は多くの場合室温の空気
で十分であるが、所望によつては50℃程度の温度
に迄加熱した空気であつてもよよい。ノズルに供
給する空気圧は、一般に1.0乃至3.0Kg／cm2（ゲー
ジ）、特に2.0Kg／cm2（ゲージ）が適当である。
本発明方法の優れた効果を次の例で説明する。
実施例
211径で内容積350mlの第３図に示すアルミニウ
ム製絞りしごき罐に胴外面塗装及び印刷を行つた
ものを、供試罐体とした。
罐底ラジアス部の塗装用塗料としては、アミノ
エポキシ塗料（フオードカツプ粘度70秒）を用い
た。
第一及び第二の塗装ローラとしては、径315mm、
単一ゴム層の厚み40mmで硬度が9゜のものを用い
た。
第４図に示す装置を用い、罐の供給速度は毎分
800罐とし、第一の塗布ローラと第二の塗布ロー
ラとの間の通過時間は195ミリセコンドであり、
エアノズルには2.0Kg／cm2（ゲージ）の室温の空
気を供給した。塗装後の焼付は、210℃で30秒間
行つた。
得られた塗装罐（試料１）について、これを硫
酸銅溶液に浸漬し、銅の析出による罐底ラジアス
部のキズ（塗膜カバレツジの不完全さ）の有無、
及びキズの長さの円周に占める比率を求めた、ま
た、罐底ラジアス部における塗膜状態を、この塗
膜を染料溶液（ブルーダイNo.３）で染色し、塗膜
状態を肉眼で観察し、その状態を評価した。更
に、罐底ラジアス部についてアルミニウムを溶解
後、膜厚を測定し、平均値とバラツキとで示し
た。
得られた結果を第１表に示す。
比較のため、第二の塗布ローラを使用せず、一
段の塗装を行う以外は前記と同様にして塗装罐を
製造した（試料２）。
また、第一段の塗布ローラと第二段の塗布ロー
ラとの間で空気吹付けを行わない以外は前記と同
様にして塗装罐を製造した（試料３）。
これらの結果も第１表に示す。
(Industrial Application Field) The present invention relates to a method for coating seamless cans, and more specifically, a method for forming an external protective coating film that is free from coating defects and has a sufficient thickness on the bottom radius of a seamless can. Regarding. (Prior Art) Seamless cans formed by drawing and ironing metal materials are widely used as pressure-resistant cans for storing contents that have their own pressure, such as carbonated drinks and beer. In this pressure-resistant can, in order to prevent so-called buckling, where the can bottom protrudes outward due to internal pressure, an inward dome is formed at the can bottom, and the can bottom dome and the can body are connected outward. Generally, a structure is adopted in which the connection is made through the can bottom radius that protrudes from the can bottom. In this seamless can, it has not yet been industrially successful to pre-print and paint the metal material before molding, and therefore it is necessary to paint each individual can after molding. For this type of seamless container, the most important point in painting is painting the can bottom radius.Since this can bottom radius comes into contact with the supporting surface during transportation and storage, there are unpainted areas in this area. Or if there are paint film defects,
Transfer troubles may occur due to poor slippage at the bottom of the can during the can making process or filling process, or corrosion may occur due to the influence of adhering water droplets. As a method for effectively forming a protective coating on the can bottom radius, Japanese Patent Publication No. 58-5712 discloses a method of applying a protective coating to the outer surface of the can bottom radius by bringing the can bottom radius into contact with a coating roller. Are listed. (Problems to be Solved by the Invention) The above-mentioned prior art is significant in that it provides a means for applying protective coating to the radius portion of the can bottom, but there are still problems with the quality of the coating film formed. I found out. That is, in FIG. 1, which shows an enlarged view of the painted state of the conventional can bottom radius,
The protective coating 6 formed on the can bottom radius portion 4 tends to be thinnest at the ridgeline 7 of the can bottom radius portion 4 and thicken on both sides thereof, and is thinnest at the ridgeline 7 where coverage is most required. There is a drawback that the film thickness becomes thinner in some areas or paint omission (unpainted areas) occurs. In addition, by increasing the coating thickness of the paint when painting the can bottom radius with the application roller,
When trying to eliminate the above drawbacks, air trapped in the paint tends to cause foaming of the paint film during the baking process, making it difficult to form a protective paint film without paint film defects. . Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks that occur when a protective coating film is formed on the outer surface of the can bottom radius by bringing the can bottom radius into contact with a coating roller, and to improve the appearance of the can bottom radius, especially around the ridgeline. An object of the present invention is to provide an improved method for reliably forming an outer surface protective coating film that is free from coating defects and has a sufficient thickness. (Means for Solving the Problems) According to the present invention, the can bottom dome portion that protrudes inwardly and the can body portion are seamlessly integrated via the can bottom radius portion that protrudes outward. In a seamless can coating method in which a protective coating is applied to the outer surface of the can bottom radius by bringing the can bottom radius into contact with an applicator roller, the can bottom radius is brought into contact with a first applicator roller to apply a protective coating to the outer surface of the can bottom radius. A first coating film is formed on the outer surface of the can, and after contact with the first application roller is released, air is blown onto the seamless can from the can bottom radius side, and then a second coating is applied to the can bottom radius. A seamless can coating method is provided, which comprises forming a second coating film on a first coating film on a can bottom radius portion by contacting with a roller. (Function) In the present invention, the roller application is performed on the can bottom radius part in two stages by contact with the application roller, and between these two stages of roller application, air is blown from the can bottom radius side. This is a remarkable feature. Following the first stage roller application, the inventors
When air is blown from the can bottom radius side onto the seamless can after the contact with the first application roller is released, there is no paint film defect on the can bottom radius, especially the ridgeline part, and the coating is sufficient. It has been found that it is possible to reliably form an outer surface protective coating film having a certain thickness. That is, by first blowing air against the first coating film formed on the can bottom radius formed by the first stage of roller coating, the solvent on the coating film surface is rapidly volatilized, thereby Setting or fixing of the coating takes place within a very short time. In this way, the coating film 6 formed by the first stage coating roller
As shown in Fig. 1, even if the wall is thinned at the position of the ridge line 7 of the can bottom radius, or there are some unpainted parts, as shown in Fig. 2, this set first coating A second coating film 8 is effectively formed on the film 6 by a second-stage application roller,
A protective coating film having no coating defects as a whole and having a sufficient thickness can be applied to the can bottom radius with a sufficient width and completely covering the ridgeline portion thereof. Moreover, the coating film produced by this two-stage application does not cause foaming of the coating film and is excellent in coating integrity. If two-stage roller coating is performed but the setting operation of the coating film is not performed afterwards, there will be large variations in the thickness of the film formed, and unlike this method, a sufficiently thick coating film with less variation can be formed. This becomes difficult. The air blowing performed after the first-stage roller application has another favorable effect in uniformly and uniformly applying the coating film to the entire circumference of the can bottom radius. In other words, the seamless can discharged from the first-stage application roller is not perpendicular to the supporting conveyance surface of the seamless can;
It is often observed that the pins have a certain deviation or are somewhat missing from the support pins. When the seamless can is fed to the second coating roller in this lopsided or almost uncoiled state, the second coating film is applied to a uniform thickness over the entire circumference of the can bottom radius. It becomes difficult to rub. In contrast, according to the present method, air is blown from the can bottom radius onto the seamless can that is released from the first-stage application roller, thereby pressing the seamless can against the support pin side.
By inserting the pin deeply and positioning the can perpendicularly to the supporting and conveying surface, it is possible to reliably perform coating with the second-stage coating roller in a correctly positioned state. (Example) No. 3 showing a seamless can used for coating of the present invention
In the figure, this seamless can 10 consists of a can bottom 2 having approximately the same thickness as the metal material used, and a can body 1 made thin by drawing and ironing. The center portion of the can bottom 2 forms a dome portion 3 that smoothly projects inward, and this dome portion 3 and the can body 1 form a ring-shaped can bottom radius portion 4 that projects outward. connected via. The can bottom radius portion 4 shown in FIG.
Of course, it does not have to protrude outward beyond the tapered portion. In FIG. 4 for explaining the coating process of the present invention, the seamless can 10 after or before the coating printing is performed on the outer surface of the can body is supported by the pin 12 of the chain conveyor 11, and the can bottom is It is introduced into the radius portion painting area 13. In this painting area 13,
A drive endless belt 14 is arranged that extends in the direction of movement of the chain conveyor 11 and is driven at a speed synchronized with the chain conveyor 11. In the painting area 13, there is a tank 1 containing paint 15.
6, a pumping roller 17 that is partially immersed in the paint, a transfer roller 18 that is in contact with the pumping roller 17 and rotates, and a first application roller 19 and a second applicator roller that are in contact with and rotate the transfer roller 18. A coating mechanism consisting of a coating roller 20 is arranged. The first application roller 19 and the second application roller 20 are spaced apart from each other and contact the transfer roller 18 at different positions. The first and second application rollers 19 and 20 have a circumferential rubber layer 21 on their surfaces.
The distance between the rubber layer 21 and the endless belt 14 is such that the rubber layer 21 applies a constant contact pressure (application pressure) to the seamless can 10 inserted therebetween. First application roller 19 and second application roller 20
An air nozzle 23 is provided between the belt 14 and the belt 14 so that the air outlet 22 faces the endless belt 14. The paint 15 in the tank 16 is pumped up by the pumping roller 1
As the roller 7 rotates, the liquid is drawn up onto the roller surface, and is supplied to the surfaces of the first coating roller 19 and the second coating roller 20 via the transfer roller 18 . First, the can bottom radius portion 4 of the seamless can 10 being conveyed while being supported by the pins 12 and the endless belt 14 comes into contact with the first coating roller 19.
Paint on the roller surface is applied to this. Seamless can 10a discharged from first application roller 19
is then blown with air from the air nozzle 23 to set the first coating film and correctly position the seamless can 10a. Next, this seamless can 10a comes into contact with the second application roller 20, and the paint on the roller surface is further applied to the can bottom radius, resulting in a seamless can 10b with the can bottom radius completely coated. Although not shown, the painted seamless can 10b is sent to a coating baking device such as an oven, which is known per se, to bake the coating. The present invention can be applied to various seamless cans.
In addition to light metals such as aluminum, the metal material that constitutes the can can be made of tinplate, galvanized steel sheet, chromium-treated steel sheet, or black plate (untreated steel sheet); Also, corrosion from the bottom of the can can be effectively prevented. As protective paints, thermosetting paints, especially modified epoxy paints, phenol-epoxy paints, amino-epoxy paints, vinyl-modified epoxy paints, etc., are used from the viewpoint of corrosion resistance, but the paints that can be used in the present invention Of course, it is not limited to this. These base resins are applied in the form of organic solvent solutions such as enamels or lacquers by the means described above. It is generally desirable that the paint used has a Ford Cup viscosity of 40 to 90 seconds, particularly 50 to 70 seconds. The thickness of the coating film (dry standard) is 4 to 4 in the first stage.
A range of 10 μm, especially 6 to 8 μm is suitable, and a total range of 7 to 13 μm, especially 9 to 11 μm is suitable. The rubber layer on the surface of the coating roller generally has an angle of 7 to 15 degrees.
In particular, hardness of 8 to 10° (measured with JIS K 6301 spring type hardness tester C type) and 25 to 45
It is preferable to have a thickness of 35 to 40 mm. The roller pressure applied to the can is preferably such that the nip width (width of application to the radius portion of the bottom of the can) is 2 to 3.5 mm, particularly 2.5 to 3.0 mm. Any rubber may be used as long as it satisfies the above conditions and has oil resistance and oil resistance, such as polyisoprene rubber, SBR, NBR, butyl rubber, chloroprene rubber, butadiene rubber, ethylene-propylene rubber, Polyurethane rubber, acrylic rubber, etc. are used. In most cases, air at room temperature is sufficient for air blowing, but if desired, air heated to a temperature of about 50° C. may be used. The air pressure supplied to the nozzle is generally 1.0 to 3.0 Kg/cm 2 (gauge), particularly 2.0 Kg/cm 2 (gauge). The excellent effects of the method of the present invention are illustrated in the following example. Example A test case was an aluminum drawn and ironed can with a diameter of 211 mm and an internal volume of 350 ml, the outer surface of which was painted and printed, as shown in Fig. 3. Aminoepoxy paint (foad cup viscosity 70 seconds) was used as the paint for the can bottom radius. The first and second painting rollers have a diameter of 315 mm.
A single rubber layer with a thickness of 40 mm and a hardness of 9° was used. Using the device shown in Figure 4, the can feeding rate is per minute.
800 cans, the transit time between the first applicator roller and the second applicator roller is 195 milliseconds,
Room temperature air of 2.0 Kg/cm 2 (gauge) was supplied to the air nozzle. Baking after painting was carried out at 210°C for 30 seconds. The obtained painted can (sample 1) was immersed in a copper sulfate solution to determine the presence or absence of scratches (incomplete paint film coverage) on the can bottom radius due to copper precipitation.
The ratio of the length of the scratch to the circumference was determined.The condition of the coating film on the radius part of the bottom of the can was dyed with a dye solution (Blue Dye No. 3) and the condition of the coating film was observed with the naked eye. and evaluated its condition. Furthermore, after dissolving the aluminum on the can bottom radius, the film thickness was measured and shown as an average value and variation. The results obtained are shown in Table 1. For comparison, a coated can was manufactured in the same manner as above except that one step of coating was performed without using the second coating roller (Sample 2). In addition, a coating can was manufactured in the same manner as above except that air was not blown between the first stage application roller and the second stage application roller (Sample 3). These results are also shown in Table 1.
【表】
以上の結果から、本発明によれば、高速塗装に
おいても、罐底ラジアス部の塗装を、塗膜欠陥な
しに、均一且つ一様に行い得ることがわかる。
（発明の効果）
本発明によれば、二段のローラ塗布の間に空気
吹付け工程を設けることにより、罐底ラジアス
部、特にその稜線の部分に未塗装部や発泡のよう
な塗膜欠陥がなくしかも十分な厚みと厚みの均一
性とを有する外面保護塗膜を一様に形成すること
ができた。[Table] From the above results, it can be seen that according to the present invention, even in high-speed coating, the can bottom radius can be uniformly and uniformly coated without any coating film defects. (Effects of the Invention) According to the present invention, by providing an air blowing process between the two-stage roller application, coating film defects such as unpainted areas and foaming can be prevented in the can bottom radius area, especially in the ridgeline area. It was possible to uniformly form an outer surface protective coating film that was free from oxidation and had sufficient thickness and uniformity of thickness.
第１図は従来法（一段塗装法）における罐底ラ
ジアス部の被覆状態を示す拡大断面図、第２図は
本発明の塗装法による罐底ラジアス部の被覆状態
を示す拡大断面図、第３図はシームレス罐の形状
の一例を示す側断面図、第４図は本発明に用いる
塗布装置の一例の配置図である。
４は罐底ラジアス部、６は第一の塗膜、７は稜
線、８は第二の塗膜、１０はシームレス罐、１９
は第一の塗布ローラ、２０は第二の塗布ローラ、
２３はエアノズルを示す。
Fig. 1 is an enlarged cross-sectional view showing the state of coverage of the can bottom radius part using the conventional method (single-stage coating method); Fig. 2 is an enlarged cross-sectional view showing the state of coverage of the can bottom radius part by the coating method of the present invention; The figure is a side sectional view showing an example of the shape of a seamless can, and FIG. 4 is a layout diagram of an example of the coating device used in the present invention. 4 is the can bottom radius part, 6 is the first coating film, 7 is the ridgeline, 8 is the second coating film, 10 is the seamless can, 19
is the first application roller, 20 is the second application roller,
23 indicates an air nozzle.
Claims (1)
が外方に突出した罐底ラジアス部を介して一体化
されているシームレス罐の罐底ラジアス部を塗布
ローラと接触させて、罐底ラジアス部の外面に保
護塗装を行なうシームレス罐の塗装方法におい
て、罐底ラジアス部を第一の塗布ローラと接触さ
せて罐底ラジアス部の外面に第一の塗膜を形成さ
せ、 第一の塗布ローラとの接触が解除された後シー
ムレス罐に対して罐底ラジアス側から空気を吹付
け、 次いで罐底ラジアス部を第二の塗布ローラと接
触させて罐底ラジアス部の第一の塗膜上に第二の
塗膜を形成させることを特徴とするシームレス罐
の塗装方法。 ２ 第一及び第二の塗布ローラとして、７乃至
15゜の硬度と25乃至45mmの厚みとを有する耐油性
表面ゴム層を備えた塗布ローラを使用する特許請
求の範囲第１項記載の方法。[Scope of Claims] 1. A roller that coats the can bottom radius of a seamless can in which the inwardly protruding can bottom dome and the can body are integrated via the outwardly protruding can bottom radius. In a seamless can coating method in which a protective coating is applied to the outer surface of the can bottom radius by bringing the can bottom radius into contact with a first coating roller, the first coating film is applied to the outer surface of the can bottom radius by bringing the can bottom radius into contact with a first coating roller. After the contact with the first application roller is released, air is blown onto the seamless can from the can bottom radius side, and then the can bottom radius is brought into contact with the second application roller to coat the can bottom radius. A method for coating a seamless can, comprising forming a second coating film on the first coating film. 2 As the first and second application rollers, 7 to 7
A method according to claim 1, characterized in that an applicator roller is provided with an oil-resistant surface rubber layer having a hardness of 15° and a thickness of 25 to 45 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15241787A JPS63319084A (en) | 1987-06-20 | 1987-06-20 | Method for coating seamless can |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15241787A JPS63319084A (en) | 1987-06-20 | 1987-06-20 | Method for coating seamless can |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63319084A JPS63319084A (en) | 1988-12-27 |
| JPH0317550B2 true JPH0317550B2 (en) | 1991-03-08 |
Family
ID=15540055
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP15241787A Granted JPS63319084A (en) | 1987-06-20 | 1987-06-20 | Method for coating seamless can |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63319084A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021181950A1 (en) * | 2020-03-09 | 2021-09-16 | 東洋製罐グループホールディングス株式会社 | Seamless can body and manufacturing method for seamless can body |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2626310B2 (en) * | 1991-06-05 | 1997-07-02 | 東洋製罐株式会社 | Bottom reinforced two-piece can |
-
1987
- 1987-06-20 JP JP15241787A patent/JPS63319084A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021181950A1 (en) * | 2020-03-09 | 2021-09-16 | 東洋製罐グループホールディングス株式会社 | Seamless can body and manufacturing method for seamless can body |
| JP2021137872A (en) * | 2020-03-09 | 2021-09-16 | 東洋製罐グループホールディングス株式会社 | Seamless can body and manufacturing method of the seamless can body |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63319084A (en) | 1988-12-27 |
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