EP0173644B1 - Process for coating sharp metal edges - Google Patents
Process for coating sharp metal edges Download PDFInfo
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- EP0173644B1 EP0173644B1 EP85810252A EP85810252A EP0173644B1 EP 0173644 B1 EP0173644 B1 EP 0173644B1 EP 85810252 A EP85810252 A EP 85810252A EP 85810252 A EP85810252 A EP 85810252A EP 0173644 B1 EP0173644 B1 EP 0173644B1
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- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D13/00—Electrophoretic coating characterised by the process
- C25D13/22—Servicing or operating apparatus or multistep processes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D17/00—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions
- B65D17/28—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
- B65D17/00—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions
- B65D17/28—Rigid or semi-rigid containers specially constructed to be opened by cutting or piercing, or by tearing of frangible members or portions at lines or points of weakness
- B65D17/34—Arrangement or construction of pull or lift tabs
- B65D17/347—Arrangement or construction of pull or lift tabs characterised by the connection between the tab and a detachable member or portion of the container
Definitions
- Metallic lids for beverage cans which usually consist of steel or aluminum or an aluminum alloy, must be provided with a device for emptying the contents which allows an opening to be torn open.
- the best known device of this type is the so-called "ring pull system", according to which an opening is marked by a notch as a predetermined breaking point. This predetermined breaking point is torn open when it is opened.
- the pouring or drinking opening is first punched into the lid made of painted sheet metal and then closed with a sealed tear-off tab. The cut edge of the punched pouring or drinking opening remains unprotected, which has a disadvantageous effect, in particular in the case of lids made of sheet steel, in two ways:
- the bare metal is exposed to the chemical attack from the product, and
- the filling material can take up metal in dissolved form, which is particularly undesirable in the case of heavy metals.
- the inventors have set themselves the task of improving a method of the type mentioned, in particular for coating cut edges of the punched pouring or drinking openings in metallic lids for beverage cans, in such a way that the disadvantages mentioned are eliminated, and in particular a complete coating of the cut edges and also from their ridges is possible. Furthermore, a food-grade coating material is to be used.
- the pore test (WACO) should result in a maximum value of 0.4 mA at a voltage of 6 V in a 1% by weight NaCI solution for the current.
- the process should also be characterized by short coating and drying times, have a minimum cadence of 60 lids per minute and should be feasible in a system with a minimum of material consumption with a reasonable amount of effort.
- lacquer particles are deposited on a metal surface from colloidal solution or a dispersion under the action of direct electrical current, similar to galvanic metal deposition.
- An insulating lacquer layer forms in the course of the electrophoresis process.
- the paint is only deposited until the entire metallic surface of the workpiece is covered with an insulation layer that prevents current flow. No deposition can be carried out on surfaces already coated before the electrophoresis process begins.
- the deposition processes take place anodically (anaphoresis) or cathodically (cataphoresis).
- the type of deposition is determined by the chemical composition of the lacquers and their conversion into the aqueous colloidal solution or dispersion.
- Can lids are made from double-sided lacquered metal tape made of steel or aluminum or an aluminum alloy, which is why electrophoretic paint can only be deposited on the bare metal cut edges of the spout openings, also called drinking openings.
- anodic-type paints which preferably consist of acrylic polymers and / or acrylic copolymers, are used. These acrylic resins are colloidally dissolved or dispersed in water with at least one amine at a pH between 8 and 10. The colloidally dissolved or dispersed lacquer is deposited anaphoretically. In anaphoretic processes, the workpiece, i.e. the lid for beverage cans, forms the anode.
- cathodic-type paints in particular epoxy esters, are colloidally dissolved or dispersed in water with an organic acid at a pH between 3.5 and 4.5.
- the preferred organic acids are vinegar or lactic acid used.
- the lacquer contained in the colloidal solution or in the dispersion is deposited cataphoretically.
- the workpiece forms the cathode.
- thixotropic agent a suitable pigmentation is added to the lacquers, whereby the edge alignment can be prevented.
- thixotropic agents such.
- B. silicon oxide with a large surface area, and / or bentonite are particularly suitable.
- Mica powder, titanium dioxide and / or calcium carbonate, for example, have proven themselves as pigment particles.
- the colloidal paint solution Dispersions advantageously have a concentration (solids content) of a total of 5-15% by weight, preferably 8-12% by weight, and an electrical conductivity of 400-1 200 JJ.8 (Mikro-Siemens).
- a rectified voltage of preferably 100-300 V is applied to the electrodes.
- the thickness of the deposited layer is dependent on this DC electrical voltage and the conductivity of the lacquer layer, which is why these must be coordinated with one another in such a way that a complete and uniform coating is produced.
- the lids treated with the electrophoretic process according to the invention are preferably immersed in the electrophoresis bath for 0.5-5 sec, in particular for 1-3 sec. A throughput of at least 60 lids per minute is thus achieved in a continuous process.
- the optimal temperature of the electrophoresis bath is in the range of 20-30 ° C, in particular 22-25 ° C, i.e. at room temperature or just above it.
- the pore test was used to measure currents of 0-0.2 mA at a voltage of 6 V.
- the expected results are achieved or exceeded in an industrial context.
- a bare cut edge 16 is formed which opens into a ridge 18 in the punching direction.
- the pouring or drinking opening 14 is closed with a hot glue flap, which consists of a thin strip 20 of an aluminum can alloy and a known sealable layer 22 applied in the direction of the lid.
- the hot glue flap is connected to the lid by means of a sealing seam 24. 1 shows the known prior art.
- FIG. 2 shows an electrophoretic layer 26 deposited according to the invention, which protects the previously bare region of the cut edge 16 against corrosive attacks and prevents contamination of the filling material with metal in dissolved form.
- FIG. 3 The system shown in FIG. 3 for the electrophoretic painting of the cut edges of pouring or drinking openings in lids for beverage cans works continuously.
- Sliding bodies 30 are displaceable and torsionally fixed on a guide rail 28.
- These sliding bodies 30 are equipped with cover holders 32 which can be displaced in the vertical direction and are pressed with their rounded shaft in the upper part by means of spring force onto a contact rail 34 which acts as an electrode.
- the contact rail In the area of the electrophoresis bath, the contact rail has a guide curve downward, as a result of which the cover holders are moved downward during a horizontal movement and the springs, which are not shown due to the clarity, are tensioned.
- a permanent magnet 38 which attracts the steel covers 40, is anchored in the center in the flat, horizontal sole 36 of the cover holders 32. Furthermore, contact needles 42 are brought into electrically conductive contact with the steel covers 40. The electrical current is connected to the cover 40 from the contact rail 34 via the cover holders 32 and the contact needles.
- a colloidal solution which functions as an electrophoresis bath 46 and into which a horizontally arranged electrode 48 is immersed, is filled into a tub 44.
- the tub 44 is provided with a supply nozzle 50 for the electrophoresis bath and with an overflow 52 which serves to maintain the bath level.
- the direct electrical current is conducted via conductors 54, 56 from the voltage poles 58, 60 to the electrodes 34, 48.
- the electrical power supply is designed such that the electrode 48 can be used both as an anode and as a cathode, as can the contact rail 34.
- the cover holders 32 are guided in the direction of arrow 62 by means of the sliding bodies 30 along the guide rail 28. Be through the contact rail 34 the cover brackets 32 are guided downward in the region of the electrophoresis bath 46 in such a way that the steel covers 40 just touch the surface thereof. The steel covers 40 are now guided along the surface of the electrophoresis bath until the contact rail 34 at the other end of the electrophoresis bath clears the way up again. After the electrophoretic coating, the steel covers 40 are guided into rinsing and drying zones (not shown) and then stripped off the cover holders 32.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Paints Or Removers (AREA)
- Design And Manufacture Of Integrated Circuits (AREA)
- Polishing Bodies And Polishing Tools (AREA)
- Details Of Rigid Or Semi-Rigid Containers (AREA)
- Containers Opened By Tearing Frangible Portions (AREA)
- Closures For Containers (AREA)
- Shearing Machines (AREA)
Abstract
Description
Verfahren zum Beschichten von Teilen von metallischen Dosen durch elektrophoretischen Auftrag in Wasser gelöster bzw. dispergierter Lacke des anodischen oder kathodischen Typs.Process for coating parts of metallic cans by electrophoretic application of lacquers of the anodic or cathodic type dissolved or dispersed in water.
Metallische Deckel für Getränkedosen, welche üblicherweise aus Stahl oder Aluminium bzw. einer Aluminiumlegierung bestehen, müssen zum Entleeren des Inhalts mit einer Einrichtung versehen sein, welche das Aufreissen einer Oeffnung gestattet. Die bekannteste Einrichtung dieser Art ist das sogenannte « Ring-Pull-System », nach welchem eine Oeffnung durch eine Kerbe als Sollbruchstelle gekennzeichnet ist. Diese Sollbruchstelle wird beim Oeffnen aufgerissen. Bei neu entwickelten Systemen wird die Ausguss- bzw. Trinköffnung zuerst in den Deckel aus lackiertem Blech gestanzt und danach mit einer aufgesiegelten Abreisslasche verschlossen. Die Schnittkante der ausgestanzten Ausguss- bzw. Trinköffnung bleibt ungeschützt, was sich - insbesondere bei Deckeln aus Stahlblech - in zweierlei Hinsicht ungünstig auswirkt :Metallic lids for beverage cans, which usually consist of steel or aluminum or an aluminum alloy, must be provided with a device for emptying the contents which allows an opening to be torn open. The best known device of this type is the so-called "ring pull system", according to which an opening is marked by a notch as a predetermined breaking point. This predetermined breaking point is torn open when it is opened. In newly developed systems, the pouring or drinking opening is first punched into the lid made of painted sheet metal and then closed with a sealed tear-off tab. The cut edge of the punched pouring or drinking opening remains unprotected, which has a disadvantageous effect, in particular in the case of lids made of sheet steel, in two ways:
Das blanke Metall ist dem chemischen Angriff durch das Füllgut ausgesetzt, undThe bare metal is exposed to the chemical attack from the product, and
das Füllgut kann Metall in gelöster Form aufnehmen, was insbesondere bei Schwermetallen unerwünscht ist.the filling material can take up metal in dissolved form, which is particularly undesirable in the case of heavy metals.
Zur Verhinderung von Korrosion am Deckel und Kontamination des Füllguts durch Metalle ist daher versucht worden, die gebildeten Schnittkanten von Ausgussöffnungen zu schützen. Dabei hat es sich als besonders problematisch herausgestellt, die Grate, die mit der Abnützung des Stanzwerkzeuges zunehmend entstehen, zu schützen.In order to prevent corrosion on the lid and contamination of the filling material by metals, attempts have therefore been made to protect the cut edges formed from pouring openings. It has proven to be particularly problematic to protect the burrs that increasingly arise with the wear of the punching tool.
Aus US-A-3 759 810 ist ein Verfahren zum Beschichten von Teilen von metallischen Dosen durch elektrophoretischen Auftrag in Wasser gelöster bzw. dispergierter Lacke des anodischen oder kathodischen Typs bekannt. Von grossem Nachteil ist aber, dass bei der Verwendung von üblicherweise im Elektrophoreseprozess eingesetzten Lacken die auf dem Metall abgeschiedene Schicht beim Einbrennen stark verflüssigt wird und von den durch die Stanzwerkzeuge hervorgerufenen Graten an den Schnittkanten des Deckels bzw. der Ausgiess- oder Trinköffnungen abfliesst. Dies gilt selbst bei zweimaligem Auftragen des Lackes.From US-A-3 759 810 a method for coating parts of metallic cans by electrophoretic application of water-based or water-borne lacquers of the anodic or cathodic type is known. A major disadvantage, however, is that when lacquers that are usually used in the electrophoresis process are used, the layer deposited on the metal becomes highly liquefied when it is burned in and flows away from the burrs caused by the punching tools on the cut edges of the lid or the pouring or drinking openings. This applies even if the varnish is applied twice.
Die Erfinder haben sich die Aufgabe gestellt, ein Verfahren der eingangs genannten Art, insbesondere zum Beschichten von Schnittkanten der ausgestanzten Ausguss- bzw. Trinköffnungen in metallischen Deckeln für Getränkedosen, so zu verbessern, dass die erwähnten Nachteile behoben werden und insbesondere eine vollständige Beschichtung der Schnittkanten und auch von deren Graten möglich ist. Ferner soll ein lebensmittelkonformes Beschichtungsmaterial angewendet werden. Der Porentest (WACO) soll bei einer Spannung von 6 V in einer 1 Gew.-% NaCI-Lösung für die Stromstärke einen Grenzwert von höchstens 0,4 mA ergeben. Weiter soll sich das Verfahren durch kurze Beschichtungs- und Trocknungszeiten auszeichnen, eine minimale Kadenz von 60 Deckeln pro Minute aufweisen und bei minimalem Materialverbrauch in einer Anlage mit tragbarem Aufwand realisierbar sein.The inventors have set themselves the task of improving a method of the type mentioned, in particular for coating cut edges of the punched pouring or drinking openings in metallic lids for beverage cans, in such a way that the disadvantages mentioned are eliminated, and in particular a complete coating of the cut edges and also from their ridges is possible. Furthermore, a food-grade coating material is to be used. The pore test (WACO) should result in a maximum value of 0.4 mA at a voltage of 6 V in a 1% by weight NaCI solution for the current. The process should also be characterized by short coating and drying times, have a minimum cadence of 60 lids per minute and should be feasible in a system with a minimum of material consumption with a reasonable amount of effort.
Die Aufgabe wird erfindungsgemäss durch die Merkmale des Anspruchs 1 gelöst, wobei Weiterbildungen des erfindungsgemässen Verfahrens Gegenstand der Ansprüche 2 bis 6 sind.The object is achieved according to the invention by the features of claim 1, further developments of the method according to the invention being the subject of claims 2 to 6.
Bei einem elektrophoretischen Verfahren zur Herstellung von Lackschichten werden aus kolloidaler Lösung oder einer Dispersion unter Einwirkung von elektrischem Gleichstrom, ähnlich einer galvanischen Metallabscheidung, Lackpartikel auf eine Metalloberfläche abgeschieden. Im Verlauf des Elektrophorese-Prozesses bildet sich eine isolierende Lackschicht. Die Lackabscheidung erfolgt nur, bis die ganze metallische Oberfläche des Werkstücks mit einer den Stromfluss verhindernden Isolationsschicht bedeckt ist. Auf bereits vor Beginn des Elektrophorese-Prozesses lackierte Oberflächen kann keine Abscheidung erfolgen.In an electrophoretic process for the production of lacquer layers, lacquer particles are deposited on a metal surface from colloidal solution or a dispersion under the action of direct electrical current, similar to galvanic metal deposition. An insulating lacquer layer forms in the course of the electrophoresis process. The paint is only deposited until the entire metallic surface of the workpiece is covered with an insulation layer that prevents current flow. No deposition can be carried out on surfaces already coated before the electrophoresis process begins.
Je nach angelegtem Spannungspotential, das am zu beschichtenden Werkstück angelegt wird, erfolgen die Abscheidungsprozesse anodisch (Anaphorese) oder kathodisch (Kataphorese). Die Art der Abscheidung wird durch die chemische Zusammensetzung der Lacke und deren Ueberführung in die wässrige kolloidale Lösung bzw. Dispersion bestimmt. Für die Beschreibung der chemischen Vorgänge der Elektrophorese wird auf den Bericht des Symposiums in Los Angeles vom 31. März bis 1. April 1973 der American Chemical Society betr. « Electro Deposition of Coatings » verwiesen, welcher von Brewer G.E. in Washington D.C. 1973 herausgegeben worden ist.Depending on the voltage potential applied to the workpiece to be coated, the deposition processes take place anodically (anaphoresis) or cathodically (cataphoresis). The type of deposition is determined by the chemical composition of the lacquers and their conversion into the aqueous colloidal solution or dispersion. For a description of the chemical processes involved in electrophoresis, reference is made to the report of the symposium in Los Angeles from March 31 to April 1, 1973 by the American Chemical Society regarding "Electro Deposition of Coatings", which was published by Brewer G.E. in Washington D.C. 1973 was published.
Dosendeckel werden aus beidseitig lackiertem Metallband hergestellt, das aus Stahl oder Aluminium bzw. einer Aluminiumlegierung besteht, weshalb nur an den metallisch blanken Schnittkanten der Ausgussöffnungen, auch Trinköffnungen genannt, eine elektrophoretische Lackabscheidung möglich ist.Can lids are made from double-sided lacquered metal tape made of steel or aluminum or an aluminum alloy, which is why electrophoretic paint can only be deposited on the bare metal cut edges of the spout openings, also called drinking openings.
Nach einer ersten Variante der Erfindung werden Lacke anodischen Typs, die vorzugsweise aus Acrylpolymeren und/oder Acrylcopolymeren bestehen, eingesetzt. Diese Acrylharze werden mit mindestens einem Amin bei einem pH-Wert zwischen 8 und 10 in Wasser kolloidal gelöst bzw. dispergiert. Der kolloidal gelöste bzw. dispergierte Lack wird anaphoretisch abgeschieden. Bei anaphoretischen Verfahren bildet das Werkstück, also der Deckel für Getränkedosen, die Anode.According to a first variant of the invention, anodic-type paints, which preferably consist of acrylic polymers and / or acrylic copolymers, are used. These acrylic resins are colloidally dissolved or dispersed in water with at least one amine at a pH between 8 and 10. The colloidally dissolved or dispersed lacquer is deposited anaphoretically. In anaphoretic processes, the workpiece, i.e. the lid for beverage cans, forms the anode.
Nach einer zweiten Variante des erfindungsgemässen Verfahrens werden Lacke kathodischen Typs, insbesondere Epoxyester, mit einer organischen Säure bei einem pH-Wert zwischen 3,5 und 4,5 in Wasser kolloidal gelöst bzw. dispergiert. Als organische Säuren werden vorzugsweise Essig-oder Milchsäure eingesetzt. Der in der kolloidalen Lösung bzw. in der Dispersion enthaltene Lack wird kataphoretisch abgeschieden. Bei kataphoretischen Lacksystemen bildet das Werkstück die Kathode.According to a second variant of the process according to the invention, cathodic-type paints, in particular epoxy esters, are colloidally dissolved or dispersed in water with an organic acid at a pH between 3.5 and 4.5. The preferred organic acids are vinegar or lactic acid used. The lacquer contained in the colloidal solution or in the dispersion is deposited cataphoretically. In cataphoretic coating systems, the workpiece forms the cathode.
Versuche haben gezeigt, dass bei der Verwendung von üblicherweise im Elektrophorese-Prozess eingesetzten Lacken die auf dem Metall abgeschiedene Schicht beim Einbrennen stark verflüssigt wird und von den Graten abfliesst. Die Lacke müssen deshalb modifiziert werden. Bevorzugt wird den Lakken ein Thixotropierungsmittel gegebenenfalls eine geeignete Pigmentierung zugesetzt, wodurch die Kantenflucht verhindert werden kann. Als Thixotropierungsmittel sind z. B. Siliziumoxid mit grosser Oberfläche, und/oder Bentonit besonders geeignet. Als Pigmentpartikel haben sich beispielsweise Glimmerpulver, Titandioxid und/oder Calciumcarbonat bewährt.Experiments have shown that when lacquers that are usually used in the electrophoresis process are used, the layer deposited on the metal is highly liquefied during the baking and flows off the burrs. The paints must therefore be modified. Preferably, a suitable thixotropic agent, a suitable pigmentation is added to the lacquers, whereby the edge alignment can be prevented. As thixotropic agents such. B. silicon oxide with a large surface area, and / or bentonite are particularly suitable. Mica powder, titanium dioxide and / or calcium carbonate, for example, have proven themselves as pigment particles.
Die kolloidale Lack-Lösung bez. -Dispersion haben vorteilhaft eine Konzentration (Festkörpergehalt) von insgesamt 5-15 Gew.-%, vorzugsweise 8-12 Gew.-%, und eine elektrische Leitfähigkeit von 400-1 200 JJ.8 (Mikro-Siemens).The colloidal paint solution Dispersions advantageously have a concentration (solids content) of a total of 5-15% by weight, preferably 8-12% by weight, and an electrical conductivity of 400-1 200 JJ.8 (Mikro-Siemens).
An die Elektroden wird eine gleichgerichtete Spannung von bevorzugt 100-300 V angelegt. Die Dicke der abgeschiedenen Schicht ist von dieser elektrischen Gleichspannung und der Leitfähigkeit der Lackschicht abhängig, weshalb diese so aufeinander abgestimmt werden müssen, dass eine vollständige und gleichmässige Beschichtung entsteht.A rectified voltage of preferably 100-300 V is applied to the electrodes. The thickness of the deposited layer is dependent on this DC electrical voltage and the conductivity of the lacquer layer, which is why these must be coordinated with one another in such a way that a complete and uniform coating is produced.
Die mit dem erfindungsgemässen elektrophoretischen Verfahren behandelten Deckel werden vorzugsweise während 0,5-5 sec, insbesondere während 1-3 sec, in das Elektrophoresebad eingetaucht. Somit wird in einem kontinuierlichen Verfahren ein Durchsatz von mindestens 60 Deckeln pro Minute erreicht.The lids treated with the electrophoretic process according to the invention are preferably immersed in the electrophoresis bath for 0.5-5 sec, in particular for 1-3 sec. A throughput of at least 60 lids per minute is thus achieved in a continuous process.
Die optimale Temperatur des Elektrophoresebades liegt im Bereich von 20-30 °C, insbesondere 22-25 °C, also etwa bei Raumtemperatur oder knapp darüber.The optimal temperature of the electrophoresis bath is in the range of 20-30 ° C, in particular 22-25 ° C, i.e. at room temperature or just above it.
Mit dem erfindungsgemässen Verfahren werden die Hauptanforderungen nach vollständiger Beschichtung der Schnittkanten und lebensmittelkonformen Beschichtungsmaterialien erfüllt. Mit dem Porentest (WACO) sind bei einer Spannung von 6 V Stromstärken von 0-0,2 mA gemessen worden. Auch in bezug auf die Wirtschaftlichkeit des Verfahrens werden in industriellem Rahmen die erwarteten Ergebnisse erzielt oder übertroffen.With the method according to the invention, the main requirements for complete coating of the cut edges and food-compatible coating materials are met. The pore test (WACO) was used to measure currents of 0-0.2 mA at a voltage of 6 V. With regard to the economic viability of the process, the expected results are achieved or exceeded in an industrial context.
Die Erfindung wird anhand von in der Zeichnung dargestellten Ausführungsbeispielen näher erläutert. Die schematischen Vertikalschnitte zeigen in
- Fig. 1 den Uebergangsbereich eines Deckels zu einer Heissklebelasche, mit blanker Schnittkante
- Fig. 2 den Uebergangsbereich eines Deckels zu einer Heissklebelasche, mit geschützter Schnittkante, und
- Fig. 3 eine Anlage zur elektrophoretischen Lackierung der Schnittkanten von ausgestanzten Ausguss- bzw. Trinklöchern in Deckeln für Getränkedosen.
- Fig. 1 shows the transition area of a lid to a hot glue flap, with a bare cutting edge
- Fig. 2 shows the transition area of a lid to a hot glue flap, with a protected cutting edge, and
- Fig. 3 shows a system for electrophoretic painting the cut edges of punched pouring or drinking holes in lids for beverage cans.
Das in Fig. 1 dargestellte Deckelmaterial 10 aus in der Verpackungsindustrie üblichem Stahlblech ist beidseits mit einer Schicht aus Lack 12 geschützt. Beim Ausstanzen der Ausguss- bzw. Trinköffnung 14 ist eine blanke Schnittkante 16 entstanden, die in Stanzrichtung in einen Grat 18 ausmündet. Die Ausguss- bzw. Trinköffnung 14 ist mit einer Heissklebelasche verschlossen, die aus einem Dünnband 20 aus einer Aluminium-Dosenlegierung und einer in Richtung des Deckels aufgebrachten bekannten siegelfähigen Schicht 22 besteht. Die Heissklebelasche ist mittels einer Siegelnaht 24 aufreissbar mit dem Deckel verbunden. In Fig. 1 wird also der bekannte Stand der Technik dargestellt.The
In Fig. 2 wird eine erfindungsgemäss abgeschiedene elektrophoretische Schicht 26 dargestellt, welche den vorher blanken Bereich der Schnittkante 16 gegen korrosive Angriffe schützt und die Verunreinigung des Füllguts mit Metall in gelöster Form verhindert.2 shows an
Die in Fig. 3 dargestellte Anlage zur elektrophoretischen Lackierung der Schnittkanten von Ausguss- bzw. Trinköffnungen in Deckeln für Getränkedosen arbeitet kontinuierlich. Auf einer Führungsschiene 28 sind Gleitkörper 30 verschiebbar und torsionsfest angeordnet. Diese Gleitkörper 30 sind mit in vertikaler Richtung verschiebbaren Deckelhalterungen 32 ausgerüstet, die mit ihrem im oberen Teil abgerundeten Schaft mittels Federkraft auf eine als Elektrode wirkende Kontaktschiene 34 gedrückt werden. Im Bereich des Elektrophoresebades weist die Kontaktschiene eine Führungskurve nach unten auf, wodurch die Deckelhalterungen bei einer Horizontalbewegung nach unten verschoben und die wegen der Uebersichtlichkeit nicht eingezeichneten Federn gespannt werden.The system shown in FIG. 3 for the electrophoretic painting of the cut edges of pouring or drinking openings in lids for beverage cans works continuously.
In der ebenen, horizontalen Sohle 36 der Deckelhalterungen 32 ist im Zentrum ein Permanentmagnet 38 verankert, welcher die Stahldeckel 40 anzieht. Weiter werden Kontaktnadeln 42 in elektrisch leitende Berührung mit den Stahldeckeln 40 gebracht. Der elektrische Strom wird von der Kontaktschiene 34 über die Deckelhalterungen 32 und die Kontaktnadeln an die Deckel 40 angeschlossen.A
In einer Wanne 44 ist eine als Elektrophoresebad 46 fungierende kolloidale Lösung eingefüllt, in welche eine horizontal angeordnete Elektrode 48 getaucht ist. Die Wanne 44 ist mit einem Zufuhrstutzen 50 für das Elektrophoresebad und mit einem der Haltung des Badniveaus dienenden Ueberlauf 52 versehen.A colloidal solution, which functions as an
Der elektrische Gleichstrom wird über Leiter 54, 56 von den Spannungspolen 58, 60 zu den Elektroden 34, 48 geführt. Die elektrische Stromzufuhr ist so ausgestaltet, dass die Elektrode 48 sowohl als Anode als auch als Kathode eingesetzt werden kann, ebenso die Kontaktschiene 34.The direct electrical current is conducted via
Während des Betriebs der Anlage werden die Deckelhalterungen 32 in Pfeilrichtung 62 mittels der Gleitkörper 30 entlang der Führungsschiene 28 geleitet. Durch die Kontaktschiene 34 werden die Deckelhalterungen 32 im Bereich des Elektrophoresebades 46 so nach unten geführt, dass die Stahldeckel 40 dessen Oberfläche gerade berühren. Die Stahldeckel 40 werden nun entlang der Oberfläche des Elektrophoresebades geführt, bis die Kontaktschiene 34 am andern Ende des Elektrophoresebades den Weg nach oben wieder frei gibt. Nach der elektrophoretischen Beschichtung werden die Stahldeckel 40 in nicht gezeichnete Spül- und Trocknungszonen geführt und dann von den Deckelhalterungen 32 abgestreift.During operation of the system, the
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT85810252T ATE48660T1 (en) | 1984-06-18 | 1985-05-31 | PROCESS FOR COATING CUT EDGES. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH2946/84 | 1984-06-18 | ||
| CH294684 | 1984-06-18 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0173644A1 EP0173644A1 (en) | 1986-03-05 |
| EP0173644B1 true EP0173644B1 (en) | 1989-12-13 |
Family
ID=4245189
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP85810252A Expired EP0173644B1 (en) | 1984-06-18 | 1985-05-31 | Process for coating sharp metal edges |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US4634508A (en) |
| EP (1) | EP0173644B1 (en) |
| JP (1) | JPS6112897A (en) |
| AT (1) | ATE48660T1 (en) |
| CA (1) | CA1258442A (en) |
| DE (1) | DE3574744D1 (en) |
| DK (1) | DK272185A (en) |
| ES (1) | ES8607428A1 (en) |
| ZA (1) | ZA854294B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63130797A (en) * | 1986-11-20 | 1988-06-02 | Kansai Paint Co Ltd | Method for preventing corrosion of edge part |
| FI96860C (en) * | 1987-06-17 | 1996-09-10 | Eisai Co Ltd | An analogous method for preparing a pyridine derivative for use as a medicament |
| DE19635560A1 (en) * | 1996-09-02 | 1998-03-05 | Basf Lacke & Farben | Non-porous coating of metal containers |
| BE1018396A3 (en) * | 2008-06-24 | 2010-10-05 | Smalt Spol S R O | Sheet metal panel NACHTRAGLICHEM WITH ANTI CORROSION AND ITS MANUFACTURING METHOD. |
| EP2599844A1 (en) | 2011-12-02 | 2013-06-05 | PPG Industries Ohio Inc. | Coating composition for a food or beverage can |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3759810A (en) * | 1971-03-29 | 1973-09-18 | American Can Co | Roll through method for electro coating can ends |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1243171A (en) * | 1963-07-26 | 1971-08-18 | Goodlass Wall & Co Ltd | Electrophoretic deposition |
| US3510022A (en) * | 1968-10-17 | 1970-05-05 | Paul H Heller | Removable tab having a protective coating |
| AT322698B (en) * | 1973-01-11 | 1975-06-10 | Stolllack Ag | METHOD AND DEVICE FOR ELECTROBLE LAYERING OF OBJECTS |
| US4005000A (en) * | 1973-09-17 | 1977-01-25 | National Can Corporation | Electrocoating apparatus and method |
-
1985
- 1985-05-31 DE DE8585810252T patent/DE3574744D1/en not_active Expired - Fee Related
- 1985-05-31 AT AT85810252T patent/ATE48660T1/en not_active IP Right Cessation
- 1985-05-31 EP EP85810252A patent/EP0173644B1/en not_active Expired
- 1985-06-06 ZA ZA854294A patent/ZA854294B/en unknown
- 1985-06-10 US US06/742,902 patent/US4634508A/en not_active Expired - Fee Related
- 1985-06-12 ES ES544098A patent/ES8607428A1/en not_active Expired
- 1985-06-17 JP JP60131622A patent/JPS6112897A/en active Pending
- 1985-06-17 CA CA000484199A patent/CA1258442A/en not_active Expired
- 1985-06-17 DK DK272185A patent/DK272185A/en not_active Application Discontinuation
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3759810A (en) * | 1971-03-29 | 1973-09-18 | American Can Co | Roll through method for electro coating can ends |
Also Published As
| Publication number | Publication date |
|---|---|
| DK272185D0 (en) | 1985-06-17 |
| US4634508A (en) | 1987-01-06 |
| DK272185A (en) | 1985-12-19 |
| DE3574744D1 (en) | 1990-01-18 |
| CA1258442A (en) | 1989-08-15 |
| ATE48660T1 (en) | 1989-12-15 |
| ZA854294B (en) | 1986-01-29 |
| ES544098A0 (en) | 1986-06-16 |
| ES8607428A1 (en) | 1986-06-16 |
| JPS6112897A (en) | 1986-01-21 |
| EP0173644A1 (en) | 1986-03-05 |
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