EP2694229A1

EP2694229A1 - Method and device for producing can bodies, and can bodies

Info

Publication number: EP2694229A1
Application number: EP12715809.5A
Authority: EP
Inventors: Werner Boltshauser
Original assignee: COSMOCAN Tech AG
Current assignee: COSMOCAN Tech AG
Priority date: 2011-04-08
Filing date: 2012-04-05
Publication date: 2014-02-12
Anticipated expiration: 2032-04-05
Also published as: EP2694229B1; CH704798A2; WO2012135968A1

Abstract

In order to produce a can body (27) having a can jacket (19) extending around a can axis in the circumferential direction, which can jacket is closed in the circumferential direction by means of an adhesive connection between contact areas (18, 18') of an overlapping region (20), a strip material (1) having the flat material regions for the can jackets (19) is guided through a printing device (2) in the longitudinal direction of the strip material and is continually printed with decorative areas (17), wherein first contact areas (18) are provided respectively next to the decorative areas (17). The flat material regions for the can jackets (19), each having a decorative area (17) and the adjacent first contact area (18), are separated from the printed strip material (1) and shaped into can jackets (19).

Description

Method and device for producing can bodies and can bodies

The invention relates to methods for producing cans according to the preamble of claim 1, to devices for producing cans according to the preamble of claim 16 and to can bodies according to the preamble of claim 14.

Can bodies are formed one or more parts. In one-piece aerosol aluminum cans, a cylindrical can body is provided by cold extrusion. Subsequently, a narrowed neck part is formed at the open end by upset necking. This manufacturing process is very complex due to the required for the many processing steps and the water and energy requirements for cleaning and drying. US Pat. No. 4,095,544 and EP 0 666 124 A1 describe the production of seam-free steel cans. In this case, the cylindrical can body is produced by punching, pressing and ironing out of a sheet metal coated with tin or plastic. When forming a narrowed can neck enormous problems can occur because the material structure is changed by the stretching or hardened. In the known one-piece cans are located on the outside cans fat or oil residues. To form a decorative layer, cleaning (washing, drying), priming (drying), printing and overcoating are performed directly on the vessel outer surface, which is very expensive.

DE 199 02 045 and US Pat. No. 6,773,217 B2 describe the coating of a tinplate belt from which blanks are punched out and these are formed by means of deep drawing into can bodies for beverage cans, with large quantities of ejection material and the already mentioned between the blanks Problems arise when creating the outer decorative layer.

When printing molded aerosol cans, the printing costs can be of the order of magnitude of the raw can price. Disturbances on the printing press lead to interruptions in can production. Another disadvantage lies in the fact that in the execution of smaller doses orders on the printing press, the printing plates or printing cylinders must be replaced, which leads to the shutdown of the entire cans production line. The printing press must be operated and monitored by a printing expert. For the production of three-piece cans sheet metal plates can be printed with grid-shaped decorations and then cut into individual frames, the frames are processed into can coats on. With known printing, the handling of the metal sheets is complicated and the solvents used are disadvantageous and restrict the location for printing, which leads to undesired transport paths. The cutting in two orthogonal directions corresponding to the respective desired can height and the corresponding can circumference is particularly complex when changing to cans with other masses. In addition, with the standard metal sheets used, there are always sheet metal sections in both directions that can not be used.

From WO05 / 000498 a solution is known in which, starting from a metal strip with a forming and a welding step, a circumferentially closed tube is produced, are separated from the shell sections for cans. At each closed with a pushed laser longitudinal seam can jacket is attached to the lower end side of a can bottom with a laser seam. At the upper end a constriction is formed. Optionally, the upper end of the can jacket is narrowed by upset necking or spin-flow necking, whereby this restriction can be carried out until the valve seat is formed. A decorative layer on the outside of the can jacket is applied to the already formed tube in the form of a printed film on the outside. To ensure that the film holds well enough on the pipe, a complex precise application and connection is necessary. Optionally, the printed film is applied to the flat metal strip prior to forming and welding the tube. This creates the undesirable expense when forming the laser longitudinal seam, because the printed film must be kept away from the laser beam.

WO05 / 068127 describes a similar production method wherein additionally the can jacket is pressed radially outwards against an inner mold. It is described a decorative film, which is optionally printed on its outside and on the inside of the can body facing with a primer and is applied after printing on the flat metal strip. A sealing layer is applied over the printing layer on the inside, which also ensures a firm sealing connection through the printing layer between the film and the metal strip. A pre-printed on the inside in a first printing and provided with the sealing layer film web is optionally printed in a further printing step on the front side. This further printing step may be performed at the can manufacturer to apply specific decor information. This means, for example, that labels are applied to a basic décor in the further printing step, which are different for the respective sales markets. The provision and application of the decorative film is thus associated with several processing steps.

According to EP 0 525 729, a decorative film is wound in the circumferential direction directly onto the can body and connected to the can body to form a closed film envelope. The separation and the application of a piece of film on the can body is very difficult, or associated with problems in thin films. From the documents US 4,199,851, DE 197 16 079 and EP 1 153 837 A1 solutions are known in which shrinkable plastic sheet wound around a winding mandrel, formed into closed envelopes and as wrap-around labels in the axial direction on bottles or cans pushed and shrunk firmly. Moving the wrap-around labels over the bottles or cans is associated with a high risk of deformation and damage, especially for thin films. In addition to the actuation and friction forces, it is possible for electrostatic charges due to friction and associated variable electrostatic forces acting on the film to occur, so that rapid transfer of the cylindrically closed film is extremely susceptible to interference.

The printing and processing methods used for cans are very costly both for direct printing of the cans and for printing and applying foils. When films are printed, more film sections must be produced than required cans, because when applying the films to a Metal strip or on the cans with rejects is expected. If you print directly on the cans, the result is a donut shot until the correct color balance is achieved.

EP 521 606 B1 describes the production of a three-part can starting from a steel strip which comprises on one side a film strip printed by gravure printing and on the other side at least one thermosetting plastic layer or a thermoplastic resin layer. In order to ensure a good connection between the steel strip and the printed foil strip, heaters with a large expansion must be used, because the high temperature must be effective for a sufficiently long time. If the connection is insufficient, deformations such as formation can occur a narrowed can neck, lead to undesirable deformation of the film relative to the sheet.

Transverse to the longitudinal extent of the steel strip, the coatings have an extension which is slightly smaller than the can circumference. From the steel strip panels or frames for can coats are separated, which are then transformed and formed by means of resistance welding to closed can coats. The weld must be covered with cover coatings. The further processing of the panels and in particular the attachment of the cover coatings is expensive.

US 2005/0043161 A1 discloses a metallic pipe section which is formed without welding from a piece of sheet metal. A molding machine brings the sheet into the closed mold in which the merged ends overlap slightly and interlock with mold elements, with an adhesive layer with glue, Klebband-, epoxy, resin, acrylic, or silicone components between the molded elements ensures a firm connection. The formation of the interlocking form elements is complex and the form elements affect the attachment of a terminating element on the pipe section. EP 1 039 200 A2 describes a metal-plastic composite tube in which a plastic inner tube is surrounded by a metal casing which is glued within an overlapping region. For bonding the overlapping metal contact layers is not a thermoplastic but a thermosetting or elastic plastic material, in particular a two- or multi-component adhesive based on epoxy resin or a copolymer based on a crosslinked / crosslinkable PE used. As an adhesive PEX material is described, which is preferably radiation crosslinked.

EP 1 551 918 B1 describes hot-sealable resin compositions which can be used in the packaging sector, whereby smaller sealing temperatures and pressures already lead to high strength due to the corresponding choice of the sealing material. This ensures a high production speed with low energy consumption. The material of the described sealing layer consists essentially of a combination of an ethylenically unsaturated ester copolymer with a resin. Preferred are an ethylene-vinyl acetate copolymer and a resin from the group consisting of aliphatic hydrocarbon resins, hydrogenated aliphatic hydrocarbon resins, aliphatic / aromatic hydrocarbon resins, hydrogenated aliphatic / aromatic hydrocarbon resins, cycloaliphatic hydrocarbon resins, hydrogenated cycloaliphatic resins, cycloaliphatic / aromatic hydrocarbon resins, hydrogenated cycloaliphatic / aromatic hydrocarbon resins, aromatic hydrocarbon resins, hydrogenated aromatic hydrocarbon resins .

Polyterpene resins, terpene-phenolic resins, tree resins, tree rosin esters, hydrogenated tree resins, hydrogenated rosin esters, grafted resins, and mixtures of any two or more thereof. Ethylene vinyl acetate copolymers are available, for example, from ExxonMobil Chemical Company as Escorene® Ultra EVA Copolymer FL01418, FL00112 and UL00109. Resins are available from ExxonMobil Chemical Company as EMPR 104 and EMPR 111, for example.

US Pat. No. 4,065,023 describes beverage cans with a tubular can jacket which is tightly closed in an overlap region by means of a bonding resin. The compound resin is applied in strips on a lateral edge of a sheet metal for the can jacket and cured after forming the sheet metal piece to the closed can jacket, so that a stable pipe section is formed. When using a biphenol-formaldehyde, a rapid curing can be ensured. In a described embodiment, a steel sheet, which is preferably coated with chromium, coated on one side, which forms the inside of the can jacket, with an organic can inner coating. On this inner coating, a polyamide adhesive tape is fixed in a strip-shaped edge region. On the sheet side, which forms the outside of the can jacket, the connecting resin is applied in a strip-shaped edge region, which adheres directly to the metal. By merging and compressing the two strip-shaped edge regions and the curing of the bonding resin, the connecting overlap area is formed.

WO 99/44768 A1 describes the production of a cylindrical can body without welding, soldering and folding connection. A piece of sheet metal is coated on both sides with a plastic material and molded into a cylindrical can jacket. The merged circumferential end portions are pressed slightly overlapping each other and treated with heat so that the plastic layers are joined together in the overlap or contact area. The preferred plastic coating material includes polyesters, polyolefins, polyamides and their copolymers, in particular Polyethylene terephthalate (PET) and polypropylene (PP). An overlap in the circumferential direction of 2 to 4 mm, a thickness of the steel sheet of 0.027 mm or 0.012 mm and a thickness of the plastic coating of 0.025 to 0.050 mm are preferred. It has also been described that the connection from the can jacket to a face-side, plastic-coated closing element also has an undercut

Heat treatment resulting connection of Kunsstoffschichten can be achieved.

In the examples, two PET coatings, namely a homopolymer based on terephthalic acid and ethylene glycol, and a copolymer based on terephthalic acid and another diacid or other dihydric alcohol. The examples also include two PP coatings, namely a copolymer with polypropylene and low polyethylene and a polypropylene homopolymer. For various pairs of interconnected, coated test metal strips with an overlap of 3mm, forces (per 1 mm stripe width) in the range of 35 to 91 N / mm were observed during tensile elongation testing. It has also been found that steel sheet without metallic surface coating or with a metallic coating can be used, in particular with an electrolytically applied chromium layer, or with a tin layer or that also galvanized steel can be used. In addition, aluminum sheet can also be used.

However, it has now been found that the known compounds without welding, soldering and folding connection have not led to a commercially viable solution.

The object of the present invention is to find a solution by means of which nozzles can be produced simply and inexpensively, wherein, in addition to the tightness of the can, its appearance should also be of high quality. The production should be done with the greatest possible flexibility and with simple facilities.

The inventive task is solved by the features of claims 1, 14 and 16. The dependent claims describe preferred or alternative embodiments.

For the printing of finished cans, very expensive and complex printing devices are used, which limit the can production to can manufacturing plants. However, the printing of sheets takes place in printing Operated on special prints and master the complex handling of the boards in printing. Only with the knowledge that directly a strip material, preferably a metal strip must be continuously printed with decorative surfaces, a solution has emerged, can be made with the cans simple and inexpensive. For printing on webs or tapes there are high-quality printing presses with high capacity. It has now been found that the printing of strip material, preferably of metal strips, is much simpler and qualitatively better than the printing of sheets or finished cans. From the continuously printed metal strip, portions or parts thereof may be used to make the can coats. Only at the end of a metal strip, a new metal strip must be used in the printing press, which is possible in known printing machines essentially without interruption. The dead metal bands are very long and therefore do not need to be changed frequently. The flexible and easy-to-use belt printing system combined with the simple can production also enables the printing of the decor and the production of the can during the filling operation.

For producing a can body with a can jacket extending in the circumferential direction about a can axis and a can bottom, can jackets are produced from flat material regions which are closed in the circumferential direction with an adhesive bond in an overlapping region. On one end of each can jacket a can bottom is attached. In the inventive solution, a strip material with the flat material areas for the can coats is guided in its longitudinal direction by a printing device for producing the can coats and continuously printed with decorative surfaces. The printing of the strip material is carried out so that in adjacent decorative surfaces, the distance between the same boundary lines in a first direction of the strip material, namely in the longitudinal direction or in the transverse direction, a first extension of the flat material areas in the direction of the can axis and transverse to the first direction of a second extension the flat material areas in the direction of the can circumference, namely at least equal to the sum of can circumference and width of the overlap region. From the printed strip material, the flat material areas for the can coats are each separated with a decorative surface and the subsequent first contact surface for the overlapping area.

Preferably, a metal strip is used as strip material. For forming the adhesive bond at the abutting contact surfaces in the overlapping area, in particular in particular provided a contact pressure and / or heat and / or UV light supplied, wherein the heat is preferably supplied inductively via the metal strip.

Particularly advantageous embodiments in which the overlap region extends around at least a circumference of the can jacket and thus a band material can be used, the thickness of which is at most half as large as the desired wall thickness of the can jacket. If the flat area of a can jacket in the circumferential direction at its two ends comprises only a single continuous layer, this area is to be regarded as a weak point. This vulnerability is preferably avoided or reduced by extending the overlap area to slightly more than one circumference. Tests on sheet metal foil sheet having a thickness of 0.05 mm have shown that the bursting pressure of can jackets increases substantially at least linearly with the number of complete wraps. If the flat material only appeared in a single layer in a peripheral section, the bursting pressure was approximately 5 bar. With each additional layer along the entire circumference, the bursting pressure increased by at least 5 bar. Coiled can coats also guarantee a higher bursting pressure compared to equally thick single-layered can coats. According to a preferred embodiment, in the printing machine, material for the adhesive bond is applied to the first contact surface for the overlapping region which adjoins the decorative surface. Starting from a standard metal strip, the high-quality pressure and at least one component for the adhesive bond can be provided with a compact device.

If the printed strip material in the printing machine is divided continuously along its longitudinal direction into at least two subbands, which each have only the decorating surface for a can jacket in the transverse direction, the separation is efficient and the subbands can be used independently of each other for the can production.

If the flat material areas for the can coats are continuously separated at the printing press, the material for the can coats can be provided very efficiently. The canned shells are preferably produced on a rotatable winding mandrel, wherein a flat material region with a decorative surface and a first contact surface is wound onto the winding mandrel so that the first contact surface meets the second contact surface in the overlapping region. To form the adhesive bond between the contact surfaces, a contact pressure and / or heat and / or UV light is applied at least in the overlapping region.

In a preferred embodiment, the connection between the can jacket and bottom of the can is formed as an adhesive bond, preferably as a positive adhesive bond with abutting abutment surfaces of the can jacket and the can bottom. This can be used to produce cans with high burst pressures.

During printing, longitudinal register marks can be arranged on the metal strip, which enable the control of separation steps so that the separated sections of the metal strip each comprise at least one complete decorative surface and contact areas for an overlapping area. If a section comprises several decorative surfaces with contact areas for overlapping areas, it is divided into parts each having a decorative surface and contact areas for an overlapping area. The sections or the parts thereof or the flat areas for the can coats are further processed into can coats. The separation of the flat material areas for the can coats can be done in the printing press. If necessary, the printed metal strip is wound up and the sections are separated later.

Preferably, the flat material areas for the can coats (sections of the metal band or the parts of the sections) after the separation step are formed into the can shell shape and connected in the overlapping area with an adhesive bond, in particular an adhesive, sealing or plastic compound, so that closed in the circumferential direction Cans coats stand by. In the inventive production of can coats made of flat material regions with a metallic layer, decorative surfaces are printed on a continuously fed metal strip, and subsequently in the later can circumferential direction a first contact surface for an overlapping region is provided to each decorative surface. The first contact surface, which adjoins the decorative surface in each case, lies in the closed can jacket on the side facing the closed jacket of the can Surface of the flat material area in such a way that the two in the circumferential direction facing away from each other edges of the decor lie together. This results in can shells, which are provided along their entire circumference with a decorative surface and have in the overlapping region a subsequent to the decorative surface first contact surface and facing away from the decorative surface, or inwardly directed second contact surface.

In the overlap region, an adhesion layer or connecting layer is formed at the two contact surfaces. The adhesion layer may be formed according to one of the compounds described in the prior art without welding, soldering and folding connection. According to the selected adhesive bond, in particular the adhesive, sealing or plastic compound, at least one component is used to create the adhesion layer. The components used can be applied directly when closing the can coats. Optionally, the metal strip is already precoated or, when the decorative surface is printed, material for the adhesive bond is applied to the overlapping region adjoining the decorative surface or, in the case of a contact surface. In order to form a firm connection in the overlapping contact areas in the overlapping area, a contact pressure is preferably provided and / or heat and / or UV light are supplied. Two-component joints provide the conditions necessary for curing.

So that plastic material or other material for the adhesive bond sufficiently well adheres to the metallic surface, an adhesion promoter is optionally applied directly to the metallic surface at the contact surfaces and on this plastic material, or optionally also another material for the adhesive bond. The plastic material, or the material for the adhesive bond, the two contact surfaces can then be joined together so that the can coats are tight and tightly closed. If an overlap region extends around at least one circumference of the can jacket, then a metal band can be used whose thickness is only half the desired wall thickness of the can jacket. With beverage cans, wall thicknesses of, for example, 0.18 mm are common. This wall thickness can already be achieved with a metal foil with a thickness of only 0.09 mm in the case of an overlap region that extends around at least one circumference of the can jacket. the. Because the adhesion layer also contributes to the wall thickness, even with a metal foil whose thickness is only 0.06 mm or 0.07 mm, a sufficiently stable can jacket can be produced. Pressure tests on such wound can coats have shown that sufficiently high burst pressures can be achieved.

When using metal strips of metal foils of small thickness arise in wound can coats at the outer end of the film only small steps on the circumference. If the metal foil extends substantially exactly over two circumference of the can jacket, the can jacket can be flattened at the two film ends, so that neither on the outside of the can jacket nor on the inside does a step appear, the middle film region between the can ends leads both ends of the film from the outside in and the two ends of the film with its end faces to the substantially radially extending middle film area. In this case, the can jacket along the entire circumference is substantially the same thickness, which is advantageous for the attachment of end elements. A disadvantage of this solution is that there is only one continuous film layer at the two ends of the film, which is to be regarded as a weak point at high internal pressures. Optionally, this weak point can be avoided or reduced by forming the adhesive bond between the end faces of the film ends and the substantially radially extending middle film region. Optionally, however, the overlap area extends over slightly more than a circumference.

It goes without saying that, in addition to the solution in which the can jacket essentially only has one layer of the metal strip or the metal foil and the overlapping area is only just so large that the required minimum pressure stability can be maintained, all solutions are also advantageous are where the overlap region extends substantially over an integer multiple of the circumference. As the number of windings increases, the film thickness can be correspondingly reduced, so that the wall thickness of the can jacket remains essentially the same.

For printing, all known printing methods can be used, wherein preferably at least one offset or a flexo or a screen printing method is used. Because the curing or drying of the colors during printing for the subsequent Further processing or must be done very quickly for the subsequent winding on a coil, the color is preferably cured by means of UV. About the colors can be applied or printed on a cover layer, which ensures about a smooth surface and a certain scratch resistance.

A longitudinal register mark in the area of each decorative surface allows the desired control of the separation steps. If a small distance or optionally an overlapping area is formed between two successive decorative surfaces, an edge of the decorative surface can also be used as a longitudinal register mark. Preferably, however, a characteristic in the decor or optionally on the edge of the decorative surface printed longitudinal register mark is used. Because no laser connection is formed on the can jacket or to a can bottom, no edge region of the can jacket must be kept free of the decor. If at least two decorative surfaces are printed side by side on the metal strip transversely to its longitudinal direction, then the metal strip must be divided into the corresponding number of partial webs. Because the two longitudinal sides of each partial web, or if appropriate the sections thereof, are not blended together and joined by means of laser welding, pressure-free edge regions and exact edges are not necessary.

So that different colors hold very well on the metal strip, a primer is preferably applied or printed before printing. The primer can be aligned on the one hand to the adhesion to the metallic surface and on the other hand to the provision of a printable surface. If these two tasks are not solved by the same paint, then a primer for the adhesion and then a top coat for the printable surface can be applied. Particularly advantageous is a primer which is applied as a sheet-metal coating or coil coating.

In coil coating, rolled metal strips are coated organically, whereby due to the simple geometry a high application efficiency can be achieved. The necessary steps are limited to painting and drying. Optionally, a cleaning, a pretreatment and / or a post-treatment is also carried out. If no fats and oils have been applied to the surface of the metal strip, cleaning can be dispensed with. It is possible, for example, to apply a first coating layer (primer) in a rolling process, to be introduced at about 240 ° C. burn, then apply a second coat of lacquer (topcoat) again by rolling and bake again at about 240 ° C. Subsequently, the metal strip can be rolled up into a coil or processed directly. The applied lacquer coatings are preferably chosen so that the adhesive bond can be formed with or on top of you.

Because coil coating is best carried out directly during the production of the metal strip, metal strips primed with coil coating are special products. However, if such a special starting material is needed for can production, it can lead to undesirable bottlenecks or problems. It is useful to produce the cans starting from metal strips, which are readily available everywhere. The common steel belts are protected against oxidation with a tin or chrome coating and optionally with grease or oil. So that common metal bands can be used, the metal band is cleaned and / or brushed if necessary and then provided with a primer directly before printing. The primer can be applied directly by a printing press, in particular only in the region of the decorative surfaces to be printed and optionally in the region of the first contact surface for the overlapping region next to the decorative surfaces. However, the primer must harden quickly, which is preferably achieved with a primer that hardens under UV irradiation.

It is possible to use solvent-borne coating systems or two-component systems (2K paints) of resin and hardener. However, systems with under UV curing primers are also advantageous. Common coating systems are based on polyester and polyurethane (and combinations), epoxy resin and polyvinylidene fluoride (PVDF). Polyurethane coatings are used as 1- and 2-component systems: the curing is carried out at room temperature or elevated temperature. For 2-component systems, polyisocyanate and a polyhydric component can be used. Polyurethane coatings are particularly suitable for coil coating processes. The first coatings suitable for metal were nitrocellulose lacquers with alkyd resins. Alkyd resins can be combined with many other film formers, such as phenolic resins and epoxy resins. Polyvinyl esters have a good adhesive power and adhere well to metallic surfaces. Acrylic resins can be used on metal in combination with other resins. The surface of the primer is chosen so that favorable printing process can be used with cheap inks. For example, it is possible to use a standard offset printing machine (film cylinder and blanket cylinder) with the versatile and, at the same time, economical oil-based inks. In addition to Haetset web offset printing inks, it is also possible to use water-dilutable or UV-curable inks and paints with solvents which dry at lower temperatures. In addition to offset printing, flexographic printing, packaging gravure printing and screen printing processes can also be advantageously used. In flexographic printing, low-viscosity ink (UV curable, solvent-based or water-based) is fed from a fountain roller to the applicator roll, and the applicator roller transfers the ink film to the raised printing plates of the forme cylinder. In gravure printing, the printing plate is inked with the wells by immersion in thin liquid paint and superfluous color with a steel knife (doctor blade) deducted.

In the packaging sector, people often work with true colors and, if necessary, with foundations. For this reason, the machines are usually equipped with a large number of inking units. In multi-cylinder machines, each printing unit has its own printing unit stand with counter-pressure cylinder and the metal strip lays a longer drying distance between the printing units. When screen printing, the ink is printed with a rubber squeegee through a fine-mesh fabric on the printed metal strip or its lacquer layer. At those points of the fabric, where no color is to be printed according to the printed image, the mesh openings of the fabric are rendered opaque by a stencil. The speed is smaller compared to other printing methods. For screen printing, many colors are offered. They differ mainly in their adhesion properties, resistance on different materials and in their drying behavior. Due to the large color range, it is also possible to use, if appropriate, a color which can be applied directly to the metal and if appropriate has similar binders, such as the primer described above. In order to achieve rapid drying or hardening of the ink, it is preferred to use inks which can be cured with UV light or optionally with electron beams.

Offset printing is used primarily when the highest quality requirements in terms of screen printing and color fidelity are required. In combination with screen printing, hot foil stamping or cold foil printing special effects can be generated. Favorable printing plates or printing rollers with flexible printing plates as well as the high degree of standardization in offset printing also make this process interesting for the printing of simpler decors at attractive prices. Wherever high coverage, detail accuracy and color strength are required to achieve brilliant, high-quality image effects, screen printing is ideally suited. Applying varnish allows special effects such as reliefs. Scented paints, thermochromatic paints and glittering paints are just a few examples of applications in screen printing. With the screen printing process, every decor can also be provided with braille braille. For the production of round screen printing plates flexible screen printing plates are used which receive the desired color transparency by exposure and further processing steps. The processing is equivalent to other photopolymer printing plates used for letterpress and flexographic printing. All work steps can be carried out quickly with a few simple auxiliary devices. From the Reprofilm to the ready-to-use printing form you need less than 30 minutes. The screen printing plates can also be digitally imaged without analogue film.

When printing on the decorative surfaces, it is also possible to provide an inking unit-like treatment station which applies at least one adhesion layer to first contact surfaces of the overlapping areas next to the decorative surfaces. It goes without saying that at least one component for the adhesion layer can also be applied with an extrusion device with a corresponding extrusion die. The adhesion layer thus applied forms a contact surface for the adhesive bond. Optionally, this adhesion layer can be connected when closing the can coats with an untreated second contact surface on the, the printed surface of the metal strip opposite, underside. Preferably, the underside of the metal strip is already precoated at least at the contact surface for the adhesive bond. Optionally, the underside of the metal strip is coated with an inking unit similar treatment station or with an Extrusonsvorrichtung, the metal strip is optionally performed with reversed surfaces by an inking similar treatment station, which at least one adhesion layer to that of the

Apply decorative surfaces facing away from tape surface or second contact surface.

Optionally, the printing press also comprises an embossing station, in which the metal strip is processed, for example, with embossing rollers. At the end of the printing press can a longitudinal cutting device are arranged, which divides the printed and slotted metal strip into subbands. The subbands can be rolled up and stored temporarily, or processed directly in parallel. On at least one end face of each can jacket, a connection region is preferably formed, on which optionally a closing part can be fastened with a further adhesive bond. Optionally, additional decor or information elements are printed on the can jacket with a digital printing system, preferably only before or after the bottling plant, thereby allowing specific, in particular individualized, information to be applied to the cans.

In embodiments that provide sections directly at the end of the printing device, a separating device is arranged there, which forms dividing lines on the flat metal strip in normal planes to the longitudinal axis of the metal strip through the metal strip. Because the metal strip is continuously moving along the belt axis during printing, the cutting device comprises cutting elements which are additionally moved along with the metal strip during their cutting movement.

A simply constructed cutting device comprises a rotating drum with radially projecting cutting edges. The axis of rotation of the drum is arranged orthogonal to the belt axis. The drum diameter is selected so that the circumference corresponds to an integer multiple of the desired length of the band sections, wherein the cutting edges are arranged at corresponding circumferential intervals on the cylindrical outer surface of the drum and lie in planes parallel to the axis of rotation. For an efficient separation step, it is expedient if the cutting edge cooperates with a support edge. Because the wall thickness of the metal strip is very small and the drum diameter is sufficiently large, the plane of the cutting edge during the cutting process is almost perpendicular to the belt axis and the resulting cutting line is then almost in a normal plane to the belt axis.

In an advantageous embodiment, a pressure-sensitive adhesive layer is transferred at least to a partial region of a contact surface of each flat material region, wherein the pressure-sensitive adhesive view is supplied on a carrier tape and transferred with a pressure device. Because the transferred pressure-sensitive adhesive areas of the contact surfaces are freely accessible, the flat material areas must after transferring the pressure-sensitive adhesive layer be wound directly as possible to Dosenmänteln, with a contact force in the pressure-sensitive adhesive areas a firm connection is achieved. For the production of can coats with an inner coating, the flat material regions are preferably wound onto a winding mandrel with a previously wound and closed inner film.

On at least one end face of each can jacket, a connection region is preferably formed on which a closure part can be fastened. Optionally, additional decor or information elements are printed on the can jacket with a digital printing system, preferably only before or after the bottling plant, thereby allowing specific, in particular individualized, information to be applied to the cans.

The processing steps of the can parts can be carried out substantially independently of the pressure lines. Only when a large part of the printing lines has problems must the can production be stopped. It is expedient to provide more pressure lines than would be necessary for the throughput of can production. This can prevent unwanted backlog before printing. In the case of parallel printing lines, the individual lines can print different decors and feed the printed can coats separately for further processing. Preferably, however, the printed canned shells subsequently reach the printing lines in a common storage area from which they are fed to the next can production step.

Preferably, the printing and / or manufacture of the can body takes place only directly before filling the cans.

For the adhesive bond between the contact surfaces of the overlap region of a can jacket, in addition to the seal or plastic compounds produced under heat also an adhesive can be used, which ensures a sufficiently strong and durable compound by surface adhesion (adhesion) and internal strength (cohesion). When the adhesives are classified according to the manner of solidification, there are adhesives which bond by physical bonding, by chemical curing or by adhesion properties without solidification mechanism achieve. The pressure-sensitive adhesives are known from adhesive tapes or self-adhesive labels and can physically set or chemically cure when applied to the support. Subsequently, they have a substantially constant adhesive property without further solidification and therefore need not be timed bound to a solidification process in the desired adhesive bond.

For compounds between metal surfaces, or metallic contact surfaces, chemically curing adhesives, especially the polymerization adhesives are well suited. Basically, a distinction is made in the reaction adhesives between two- (or more) -component and one-component systems. For 2-component adhesives, two spatially separate preparations are used, usually labeled "A" and "B". In these, the monomers are as basic building blocks of the resulting polymer in the reaction. One of the two formulations contains resin monomers (or binders) while the other contains hardeners. With the contact of resin and hardener, the chemical reaction to the adhesive polymer starts. This requires that 2-component adhesives can only be processed within the so-called pot life. After application of the adhesive follows the curing time, in which builds the final strength of the bond. This curing time is strongly influenced by the composition of the adhesive and external influences, especially the temperature. An increase in temperature leads to an accelerated hardening and often also to a higher strength. Particularly suitable polymerization adhesives are methyl methacrylate (MMA) adhesives which are UV, chemical and water resistant and for use temperatures from -40 to +120

° Celsius are suitable. If adhesives are used which cure chemically in the adhesive bond, it is expedient to apply these adhesives directly prior to the closure of the can coats or of the pipe in order to achieve a constant bond quality. However, the application of adhesive requires a system with a more complex structure and a more complex operation.

In a preferred embodiment, at least one component for the adhesive bond is applied to the strip material with the flat material areas for the can coats prior to the separation of flat material areas. For example, the components for sealing or plastic compounds can be applied to the strip material. In a particularly advantageous embodiment, a pressure-sensitive adhesive is applied to the strip material, which merely forms an adhesive bond when the can shells are closed between the contact surfaces of the overlapping area without a hardening mechanism by pressing. As a result, it is possible to dispense with application devices for adhesives and heating devices for sealing or plastic connections when closing the can shells.

To provide flat material areas for the can coats, a metal strip is preferably used which has a pressure-sensitive adhesive layer for forming the adhesive bond of each can jacket at least in each case one of the contact surfaces connected to one another in the overlap region, wherein a contact pressure is provided when forming the adhesive bond in the contact surfaces to be joined together becomes. In order that the adhesion of the free surface of areas applied to the strip material, or preferably of a continuous layer, with pressure-sensitive adhesive can not be impaired prior to the closure of the can coats, a protective layer is arranged on the free surface of the pressure-sensitive adhesive. Preferably, the strip material is a layer of a multilayer composite material which comprises at least the printed strip material, a pressure-sensitive adhesive layer well bonded to the inside of the strip material facing away from the printed side of the strip material, and a carrier strip preferably provided with a silicone layer which forms the protective layer for forms the pressure-sensitive adhesive and due to a reduced adhesion to the pressure-sensitive adhesive layer can be easily removed from this. The multilayer material composite can be advantageously built up by coating a carrier tape with a release coating and, on this release coating, with pressure-sensitive adhesive. The strip material for the can coats, preferably a metal strip, is then pressed against the pressure-sensitive adhesive layer of the carrier strip, wherein the contact surface of the strip material is preferably processed, in particular degreased or coated, for permanent connection with the pressure-sensitive adhesive.

From the field of self-adhesive labels, a large selection of pressure-sensitive adhesives is known, in particular those with high adhesion and resistance in large ranges of temperature and humidity. Particularly suitable for the production of can shells, especially those with sections of metallic strip material, are acrylate-based pressure-sensitive adhesives. For special applications are also UV-polymerizable Pressure-sensitive adhesives can be used. The latter are liquid at room temperature and can be processed instead of a printing ink via a screen or flexo printing unit. If necessary, the adhesive (eg Novarad RCL 6011) can only be partially applied to the desired locations. Immediately after application of the adhesive, UV crosslinking occurs, causing the adhesive to polymerize, giving it inner strength and a sticky surface.

The multi-layer composite material thus corresponds to a conventional in self-adhesive labels construction, the tape material for the can coats is preferably formed of metal. As with the production of self-adhesive labels, the tape material for the can coats is provided with the pressure-sensitive adhesive layer and the carrier tape. This multilayer material composite can be wound up on large rolls. Subsequently, the multilayer material composite is guided in its longitudinal direction through a printing press. In steps of printing, the material composite on the side with the strip material for the dosh shells is printed with decorative surfaces. From the printed strip material, the flat material areas for the can coats are punched out, that is to say the flat material for the can coats is cut as the uppermost layer of the material composite according to the contour of the required flat material areas for the can coats. The punching on the band-shaped composite material in the printing press can be easily achieved with two cooperating drums, wherein at least on one of the two drums cutting edges are formed, which form the desired cutting lines.

The punching achieves at least one cutting line transverse to the longitudinal axis of the strip material. If necessary, rectangles are punched out of the strip material and the so-called grid, namely the material around these rectangles, is pulled off. When punching the flat material areas for the can coats, the carrier tape must not be damaged. After punching and, if appropriate, removal of the grid, the band-shaped composite material comprises the carrier band and the detachable flat material areas for the can coats, which comprise the printed decoration on one side and a layer of pressure-sensitive adhesive on the other side.

The carrier tape can comprise more than one removable flat material region for the can coats transversely to its longitudinal direction, in which case it is cut into single-layer can jacket layers in a packaging step. When the carrier tape with the detachment Baren flat material areas for the can coats is rolled into rolls, the can production can be carried out decoupled from the printing device.

During the can production, an adhesive bond must be formed between the contact surfaces of the overlap region in the case sleeves made of flat material regions. At least in the area of this adhesive bond, a corresponding area of the carrier tape must be removed from the layer with the pressure-sensitive adhesive.

Optionally, the flat material areas for the can coats are detached from the carrier tape and formed into the desired shell shape such that a region of the layer of the pressure-sensitive adhesive forms the desired adhesive bond in the overlapping area. To detach the flat material areas, the carrier tape is pulled taut over a blade-shaped dispensing edge. In the process, the area of the flat material area with the layer of the pressure-sensitive adhesive separates from the carrier strip because of the greater rigidity of the flat material area and the reduced adhesion of the carrier strip to the layer of the pressure-sensitive adhesive. For a good release, the carrier tape is as thin as possible and the flat material region or the band material is selected with sufficient rigidity. In addition, the adhesion between the pressure-sensitive adhesive and the carrier tape or its release coating is chosen so that the detachment takes place only at the dispensing edge and not at pulleys.

If now the detached flat material region is preferably formed on a mandrel to a can jacket, the winding mandrel and after separation from the winding mandrel the can interior facing a layer of the pressure sensitive adhesive, which is not suitable as an inner coating due to the adhesive property. In order to provide a suitable internal coating and to facilitate the release of the can jacket from a mandrel optionally used, a film-shaped inner layer can first be wound on a mandrel and sealed tightly in an overlapping region. A detached flat material region can then be wound onto this tubular closed inner layer and sealed with its overlap region. The film-shaped inner coating may be formed on the outwardly-facing surface so that the pressure-sensitive adhesive of the sheet-material region applied thereto forms a firm connection, which increases the stability of the can jacket. If the inner coating after use of the can, or when disassembling the same, to be separated from the flat material area, it is between the inner coating and only minimal adhesion is provided to the pressure-sensitive adhesive of the flat material area which is in contact therewith.

In a preferred embodiment, portions of the carrier tape are used directly for the inner layer, which are available after such detachment of the flat material areas for such use. This reduces the total material consumption. Also, the weak adhesion between the release coating of the carrier tape and the pressure-sensitive adhesive layer on the flat material regions, together with the dimensional stability, is sufficiently large to keep the inner layer on the flat material region. If portions of the carrier tape are used as the inner layer, then a carrier tape can be used, which is provided on the side remote from the release coating side with a suitable for the respective can filling inner coating. Optionally, the portions of the carrier tape can be used so that the release coating is directed inwards, thereby forming an inner coating. Accordingly, the side facing away from the release coating side of the carrier tape is preferably selected so that it adheres well to the pressure-sensitive adhesive layer.

In the solutions which use sections of the carrier tape for the inner layer, these sections are preferably already punched out at the printing press, that is to say the carrier tape is cut as the lowermost layer of the material composite according to the contour of the required sections for the inner layer. The punching comprises at least one cutting line transverse to the longitudinal axis of the strip material. If necessary, rectangles are punched out of the strip material and the so-called grid, namely the material around these rectangles, is subtracted. When punching the sections of the carrier tape, the strip material must not be damaged by the flat areas for the can coats. The punching on the band-shaped composite material in the printing press can be easily achieved with two cooperating drums, wherein at least on one of the two drums cutting edges are formed, which form the desired cutting lines.

After the two-sided punching (strip material and carrier tape) and optionally the removal of grids of the band-shaped composite material portions of the carrier tape and the flat material areas for the can coats, which comprise the printed decor on one side and a layer of pressure-sensitive adhesive on the other side. So that material composite continued after punching as a coherent band can be, the edges of the portions of the carrier tape and the flat material areas are arranged offset in the tape longitudinal direction to each other. Each section of the carrier tape forms a connection between adjoining flat material regions, which connection enables the continuation of the band-shaped composite material, or can absorb the necessary tensile force. Because the overlapping areas of the inner layer and the flat material regions formed into can jackets can have different sizes or widths, the spacings between the sections of the carrier strip and the flat material regions can differ. Now that a coherent carrier tape is missing, the detachment of the flat material areas can not be achieved by pulling the carrier tape around a dispenser edge. In addition, the tensile forces must be transferred to the band-shaped composite material in a feed area before the detachment of the flat material areas and thereby move the free end forward. In a possible separation process, the front side of a flat material region is gripped and pulled around a dispensing edge with the portion of the carrier tape adhering to the flat material regions, so that the next flat material region separates from the portion of the carrier tape between the two flat material regions. This results in elements each having a flat material region and a portion of the carrier tape, these parts overlap only partially. These elements can be wound on a winding mandrel from the section of the carrier strip, so that preferably a tightly closed tube element is formed by connecting the adjoining regions of the section of the carrier strip, for example with an adhesive bond or with a heat-sealed or plastic compound. The subsequently wound flat material area forms the adhesive bond in the overlap area and thus ensures that the resulting can jacket is permanently closed. Optionally, however, the two elements are separated from each other by a movement with the portion of the carrier tape via a dispensing edge. Then, the portion of the carrier tape before winding on the winding mandrel can still be rotated so that the separating layer is directed against the interior of the resulting canned casing.

In a further preferred embodiment, portions of the carrier tape are also used as an inner layer, but not in the production of can coats not flat material areas are detached from the carrier tape, but in the tape forward direction preceding initial areas of the sections of the carrier tape from the flat material areas detached and wound at least once around a mandrel and preferably closed tubular. To detach the initial regions of the sections of the carrier tape, a roller with suction region can be used, wherein the suction force is adjusted so that the carrier tape is detached from the pressure-sensitive adhesive layer. For dense shooting, if necessary, an adhesive bond or with heat a seal or plastic connection between the abutting areas of the portion of the carrier tape is formed. Subsequently, a circumference of the winding mandrel is wrapped with the material composite, that is to say the portion of the carrier strip and a flat material region abutting thereon. During a further wrapping of the winding mandrel, only the remainder of the flat material region is then wound up with the pressure-sensitive adhesive but without carrier tape, so that the adhesive bond in the overlapping region is created. The section of the carrier tape in this end region of the flat material region is then already wound up for the next can jacket on a further winding mandrel.

When using the sections of the carrier tape as the inner layer of the can jacket essentially the entire composite material is processed in canned coats, so both the strip material and the carrier tape. The preferred embodiments have thus overcome the prejudice that a can of a can body and then attached thereto label must be constructed. The label is processed directly to the can jacket and the carrier tape to the inner layer.

The drawings illustrate the inventive solution based on embodiments. It shows

1 is a schematic representation of a printing device,

2a is a plan view of a metal band with printed decorative surfaces and longitudinal contact surfaces for overlapping areas, their circumferential direction extending in the longitudinal direction of the metal strip and the extension running in the direction of the can axis transverse to the longitudinal direction of the metal strip, FIG.

2b shows a schematic view of a web with decorative surfaces and in the longitudinal direction depending subsequent contact surfaces for overlapping areas, wherein each decorative surface is formed with contact surface in the web longitudinal direction to form a can jacket, 3a is a plan view of a metal strip with printed decorative surfaces and laterally each subsequent contact surfaces for overlapping areas, wherein the circumferential direction extends transversely to the longitudinal direction of the metal strip and the extension in the direction of the can axis in the longitudinal direction of the metal strip,

3b is a schematic view of a web with decorative surfaces and laterally each subsequent contact surfaces for overlapping areas, each decorative surface is formed with contact surface transverse to the web longitudinal direction to a can jacket,

4a, 4b, 4c cross sections through can coats with different sized overlapping areas,

Fig. 5 is a schematic representation of the steps and apparatus used for the

Creating can coats are used with decorative surfaces and interior coating,

Fig. 6 to 9 perspective views of different doses

10 is a section through a double-fold connection between the can jacket and bottom of the can according to the prior art,

1 1 shows a section through a double-fold connection between the can jacket and the can lid according to the prior art,

12 shows a section through an adhesive bond between the can jacket and the can lid according to the prior art,

13 is a section through a positive adhesive connection between the can jacket and bottom of the can,

14 shows a section through a positive adhesive connection between the can jacket and the can lid,

15 shows a section through a positive adhesive connection between the can jacket and bottom of the can,

16 shows a schematic illustration of the processing steps for the production of a wound can,

17 shows a cross section through a can jacket with a circumferentially closed inner layer and a flat material region with a pressure-sensitive adhesive layer,

18 is a section through a multilayer composite material,

19 is a schematic representation of a system for producing cans, and FIG. 20 is a section of the first turntable 45 of FIG. 19 Optionally, a cleaning station 3 is provided, in which the surface to be printed of the cladding tape 1 is cleaned or treated so that the applied first layer holds sufficiently stable on the metal surface. The treatment may include washing, brushing and / or further mechanical treatments. Optionally, a laser or plasma surface treatment is provided. After optionally provided primary drying 4, a base coat 5 can be carried out. According to the selected adhesive bond, in particular the adhesive, sealing or plastic compound, at least one component can be applied in the overlapping areas for the adhesion layer during printing, in particular in the case of the basecoat 5. According to the primer used and / or the at least one component for the adhesion layer, a hot-air drying 6 and / or a UV drying 7 is provided. After various printing steps 8, a UV drying 7 is preferably carried out in each case.

Optionally, the printing machine 2 also includes an embossing station 9, in which the metal strip is processed, for example, with embossing rollers. The embossing station 9 comprises a rotating drum with curved embossing surfaces, which are assigned to the already printed decorative surfaces during embossing. The axis of rotation of the drum is arranged orthogonal to the longitudinal axis of the metal strip 1. The drum diameter is selected such that the circumference corresponds to an integer multiple of the decorative extent in the longitudinal direction of the metal strip 1 or the sum of the decorative extent and the extent of the overlap region in the longitudinal direction of the metal strip 1, wherein the embossing surfaces corresponding to the cylindrical outer surface of the drum are arranged. For a good embossing step, it is expedient if the embossing surfaces cooperate with a somewhat elastic support roller 10 or a support roller with support surfaces adapted to the embossing surfaces. So that embossing does not affect the adhesive bond, it is preferably used only when can coats are produced with a circumferentially short overlap area.

2a shows a first embodiment of a metal strip 1 with printed decorative surfaces 17 and in the longitudinal direction of the metal strip each subsequent first contact surfaces 18 for forming can coats 19 with overlapping areas 20. The circumferential direction of the flat material areas for the can coats extends in the longitudinal direction. direction of the metal strip 1 and the extension in the direction of the doses axis is transverse to the longitudinal direction of the metal strip. The width b of the metal strip 1 comprises a plurality of juxtaposed flat material areas for the can coats with decorative surfaces 17 and first contact surfaces 18, wherein the width b corresponds to a multiple of the height h of the can coats.

Fig. 3a shows another embodiment of the metal strip 1 with printed decorative surfaces 17 and transverse to the longitudinal direction each subsequent first contact surfaces 18 for forming can coats 19 with overlapping areas 20. The circumferential direction of the flat material areas for the can coats extends transversely to the longitudinal direction of the metal strip 1 and the height In the illustrated embodiment, the width b of the metal strip 1 comprises two can jacket areas arranged next to one another with decorative surfaces 17 and first contact surfaces 18.

In the case of adjacent decorative surfaces 17 on the continuously printed strip material 1, the distance between the same boundary lines in a first direction of the strip material (1), namely in its longitudinal direction or in its transverse direction, corresponds to a first expansion of the flat material regions in the direction of the can axis and transversely to the first direction a second extent of the flat material regions in the direction of the nozzle circumference, namely at least the sum of the can circumference and the width of the overlapping region 22.

A longitudinal cutting device 11 can be arranged against the end of the printing machine 2, which divides the printed and optionally embossed metal strip 1 into sub-strips 1a (FIGS. 2b and 3b). The longitudinal cutting device 11 comprises at least one first cutting ring 12, which optionally cooperates with a second cutting ring or a support ring 13. Of the sub-bands 1a, sections 1b with only one decorative surface 17 and a first contact surface 18 can be separated directly at the printing press 2 or optionally only at a further processing station, in particular during a filling operation with a cross-cutting device 14. Optionally, the sub-bands 1a are rolled up and stored before the sections 1b are severed.

It goes without saying that the width of the metal strip and only a height of the can coats or only the sum of the lengths of the decorative surface 17 and the first Contact surface 18 in the circumferential direction of the can coats may correspond. Then the metal strip 1 is not divided into subbands.

A transverse cutting device 14 comprises, for example, a rotating drum 15 with radially projecting cutting edges 16. The axis of rotation of the drum 5 is arranged orthogonal to the longitudinal axis of the metal strip 1. The drum diameter is selected so that the circumference corresponds to an integer multiple of the desired length of the sections to be separated, wherein the cutting edges 16 are arranged at corresponding circumferential spacings on the cylindrical outer surface of the drum 15 and lie in planes parallel to the axis of rotation. For a good separation step, it is expedient if the cutting edges 16 cooperates with a support roller 10, in which case preferably the cutting edges 16 cooperate with supporting edges of the support roller 10. Because the thickness of the metal strip 1 is very small and the drum diameter is sufficiently large, the plane of the cutting edge 16 is almost perpendicular to the metal strip 1 during the separating step.

FIGS. 4a, 4b and 4c show cross-sections through can coats 19 with overlapping regions 20 of different sizes. The can coats are provided with a decorative surface 17 along their entire circumference and have in the overlapping region 20 a first contact surface 18 adjoining the decorative surface 17 and one of FIG the decorative surface 17 facing away, or inwardly directed, second contact surface 18 'on. In Fig. 4a, a minimum overlap, namely a small portion of the circumference, has been selected. Fig. 4b shows an embodiment in which the overlap region 20 extends completely around a circumference of the can jacket. The thickness of the metal strip used is only half as large as the wall thickness of the can jacket. The can jacket is flattened at the two film ends of the metal foil or the portion of the metal strip, so that neither on the outside of the can jacket still on the inside of a step appears. The middle area of the film leads from the outside to the inside between the two ends of the film and the two ends of the film stand with their end faces against the essentially radially running middle area of the film. The can jacket is thus substantially the same thickness along the entire circumference, which is advantageous for the attachment of end elements. If there is only one continuous film layer at both ends of the film, this area should be regarded as a weak point. If necessary, this weak point can be avoided or reduced in that the adhesive bond between the end faces of the film ends is formed to the substantially radially extending middle film region. Optionally, however, the overlapping area extends as in the embodiment according to FIG. 4c over slightly more than one circumference. Fig. 5 shows an embodiment in which the metal strip 1 includes only one row of can jacket areas whose extension in the longitudinal direction of the metal strip 1 corresponds to the can height. The metal strip 1 is formed in a shaping device 21 transversely to its longitudinal direction into a tube with an overlapping area and closed in the overlapping area with an adhesive bond, in particular an adhesive, sealing or synthetic material compound. A pipe section separator 22 separates pipe sections, each with a complete decorative surface 17, which are used as circumferentially closed can coats. The feed of the resulting tube is achieved with a drag crawler device 23. A sensor device 24 can detect longitudinal register marks and control the separating steps so that the separated can coats each comprise a complete decorative surface 17. The adhesive bond in the overlapping area is achieved with a connecting device 25, which preferably provides a required temperature and a required contact pressure and if appropriate also supplies at least one material component for the adhesive bond. Optionally, after the formation of the adhesive bond and before the separation of the pipe sections or can shells 19, a tubular inner coating is attached to the inside of the resulting pipe. For this purpose, for example, an extrusion device 26 can be used which comprises an extrusion die, an extrusion die, at least one line leading into the extrusion die and at least one extruder, the extruder feeding at least one line with the material to be extruded. The extrusion die and the extrusion die are associated with the interior of the resulting pipe and are held from the side where the metal strip 1 is still open. On one end of each can jacket a can bottom is attached. Optionally, the upper end of the can is formed according to the desired type of can or provided with a lid.

Figures 6 to 9 show various three-piece cans 27, the can jacket 19 can be formed with an adhesive bond. The final connections 34 from Can jacket 19 to the bottom of the can and / or to the can lid or to the upper end of the can also be formed as adhesive bonds. 6 shows an aerosol can, FIG. 7 shows a beverage can, FIG. 8 and 9 food cans. All of these cans can be made with can jackets 19 which are closed in an overlap area with an adhesive bond.

Fig. 10 shows a known double-folded joint 28 between the can jacket 19 and bottom of the can 30. Fig. 1 1 shows a known double-fold connection between the can jacket 19 and can lid 31. Achieving the tightness of the double Falzverbindungen is difficult for thin can coats 19. FIG. 12 shows a known adhesive bond between the can jacket 19 and the can lid 31, wherein plastic coatings 32 of the can jacket 19 and the can lid 31 are connected to one another under the effect of heat in such a way that an adhesive bond is created. The illustrated adhesive bond is not suitable for all cans, because no high bursting pressures can be achieved.

FIGS. 13 and 14 show positive adhesive bonding 34 between can jacket 19 and can bottom 30 and can lid 31. These positive adhesive bonds 34 comprise abutting abutment surfaces 33 of the can jacket 19 and the can bottom 30 and the can lid 31. In the illustrated embodiment, the abutment surfaces 33 formed by once folded end portions. In the case of thin metal sheets, it is advantageous if the abutment surfaces 33 are formed by rolling in the end regions, in particular by folding over the end regions twice, which then have a sufficiently extended abutment surface 33.

To form the positive adhesive connections 34, the encompassing connecting part is pushed in the open state over the inner connecting part and then pressed so that the abutment surfaces 33 of the two parts lie opposite each other in the direction of the can axis. In order to enable the adhesive bond, at least mutually facing annularly closed partial surfaces of the can jacket 19 and the can bottom 30 and the can lid 31 are provided with a coating 35, which annularly closed partial surfaces can be connected to one another by pressing and applying heat. Optionally, the sheet metal of the can jacket 19 and the can bottom 30 or the can lid 31 is provided on one or, if appropriate, on both sides with a coating 35. 15 shows a further embodiment of a positive adhesive bond between the can jacket 19 and a can bottom 30 inserted from the inside of the can. The can jacket 9 is narrowed at the lower end and optionally comprises a groove which is open from above. The can bottom 30 is adapted to the constriction and groove and is fixed in the overlap region with an adhesive bond on the can jacket 19.

Fig. 16 shows the processing steps for the production of a wound can. Optionally, in a step 1, a closing element, namely a can bottom 30 or a can lid 3, is arranged on a rotatable winding mandrel 36. If only a can jacket is made, this step 1 is omitted. In a step 2, an inner film 37 is wound onto the winding mandrel 36 and optionally the outer edge of the closing element 30. In a step 3, a section 1 b with a decorative surface 17 and a first contact surface 18 is wound around the inner film 37 onto the mandrel 36 and optionally the outer edge of the end element 30. At least part of the first contact surface 18 is coated on the section 1 b and, in the overlapping region 20, strikes the second optionally also coated contact surface 18 '. In a step 4, at least in the overlap region, a contact pressure and / or

Applied heat, so that from the section 1 b with a bonding a closed can jacket 19 is formed. Preferably, the inner film 37 on the outer side comprises a sealing layer, which is heated and on the one hand in a film overlap, the inner film 37 closes tightly in the circumferential direction and on the other hand creates a connection to the metallic can jacket 19 and the end element 30. The heat required for the sealing is preferably produced inductively by an induction and pressing device 38 in the metallic can jacket 19 and in the closing element 30. In an optionally provided step 5, which may preferably also be carried out before step 4, the end region of the can jacket 19 is narrowed with a shaping device 39 and applied to a corresponding region of the closure element 30. If the step 5 is performed after the step 4, heat may be supplied in the narrowed and applied area to form a sealed joint. In a step 6, a cylindrical can body is separated from the mandrel 36, possibly by the circumference of the winding mandrel is slightly reduced. On the outside of the can body is the printed on the metal strip decorative surface 17 and on the inside of the inner foil.

When using a hose-like winding mandrel, the can body could also be brought into an inner shape by expanding the winding mandrel into a shape corresponding to the inner mold. If appropriate, the can jacket 19 is constructed without a closure element 30 in accordance with the steps described above, so that the molding step in the inner mold can be carried out on the can jacket without a closure part 30. During the molding step, essentially the end shape of the can jacket can be formed together with at least one connection or contact region for a closure element. At least one end element is then then at least one Anschlußbzw. Contact area of the can jacket fixed with an adhesive bond. If appropriate, the second closure element is brought into position on the can jacket and then the end region of the can jacket is narrowed with a shaping device and applied to a corresponding region of the second closure element. In the narrowed and applied area heat can be supplied to form a sealed joint.

It is self-evident that a can bottom and / or a can lid can be fastened to an inventive can jacket by means of a binding or welding connection known from the prior art.

FIG. 17 shows an embodiment in which the can jacket 19 comprises an inner layer 40 which is closed in the circumferential direction and a flat material region 41 with a pressure-sensitive adhesive layer 42. The flat material region 41 extends a little more than twice around the circumference of the shell, and correspondingly the overlapping overlapping region 20 extends a little more than once around the circumference of the shell. The can coats 19 are provided outside along their entire circumference with a decorative surface 17 and have in the overlapping region 20 a subsequent to the decorative surface 17 first contact surface 18 and facing away from the decorative surface 17, or inwardly directed, second contact surface 18 'on.

The illustrated can jacket 19 was pressed after winding the components around a winding mandrel in an inner mold, so that its outer contour is substantially circular. As a result of the pressing process, the outer end of the flat material region 41 together with the pressure-sensitive adhesive layer 42 could penetrate into the wall of the can jacket be pressed. Accordingly, the inner layer 40 is slightly in the overlap region 20 against the can axis. By close connection of the two end regions of the inner layer 40 wound on a mandrel portion of an inner film or optionally a carrier tape creates a can jacket 19 with a den th inner barrier and two layers of the flat material portion 41 together with the pressure-sensitive adhesive layer 42. The adhesive bond between the contact surfaces 18 and 18 'is formed by the pressure-sensitive adhesive layer 42. The pressure-sensitive adhesive layer 42 also forms an adhesive bond to the inner layer 40, which is sealed in the circumferential direction in the case of an inner-layer overlapping region 20 '.

18 shows the metal strip 1 for the flat material regions 41 as a layer of a multilayer composite material comprising, in addition to the metal strip 1, a pressure-sensitive adhesive layer 42 well bonded to the metal strip 1 and a carrier strip 43 preferably provided with a silicone layer 43a. The carrier tape 43 forms the protective layer for the pressure-sensitive adhesive and can be easily removed from it due to reduced adhesion to the pressure-sensitive adhesive layer 42. The multilayer material composite can be advantageously constructed by coating a carrier tape 43 with a release coating 43a and on this release coating with a pressure-sensitive adhesive layer 42. The strip material for the can coats, preferably a metal strip 1, is then pressed against the pressure-sensitive adhesive layer 42 of the carrier strip 43 to form a permanent bond.

Fig. 19 shows a plant for producing cans. From a roller 44, a multilayer material composite of a first processing station 45, preferably a turntable supplied. The multilayer material composite comprises at least the printed strip material, a pressure-sensitive adhesive layer well bonded to the inside of the strip material facing away from the printed side of the strip material, and a carrier strip, preferably provided with a silicone layer, which forms the protective layer for the pressure-sensitive adhesive and due to reduced adhesion can be easily removed from the pressure-sensitive adhesive layer of this. The multilayer composite material is fed via a feeding device, not shown, in sections, each with a preceding region of the carrier tape and a subsequent, preferably partially overlapping, region of the printed strip material on first processing elements 46 in the form of mandrels. The can shells are wound on the winding mandrels during a rotary movement of the turntable and the closure of the carrier strip sections to internal barriers as well as the tight formation of the adhesive bonds between the contact surfaces. performed. A first transfer station 47 transfers the can coats to a second processing station 48 with second processing elements 49, at which preferably the upper end region of the can coats is neck-shaped narrowed. For each of these constrictions, a reshaping step adapted to the desired can is used. With a transfer system 50, the processed can jackets of a third processing station

51 supplied with third processing elements 52. With the third editing elements

52 cans are attached to the can coats cans. The ready for filling cans are continued via a discharge station 53, preferably to the filling station, but possibly in a storage area.

Fig. 20 shows a section of the first processing station 45, or the turntable 45. On the turntable 45 winding mandrels 54 are arranged rotatably about their own axis, being rotated during manufacture of the can coats with the turntable 45 about its axis and at the same time about its axis , On the cylindrical lateral surfaces of the winding mandrels 54, suction regions 55 are formed, which extend over at least part of the mandrel circumference and over the entire mandrel height or over the width of the multilayer composite material supplied by the roller 44 and are connected to a suction device such that the suction with each winding mandrel 54 individually targeted and can be turned off.

The supplied material composite comprises a metal strip 1 interrupted by dividing lines 1 ', a pressure-sensitive adhesive layer fixedly connected to the metal strip 1 and a carrier strip 43. The carrier strip 43 is likewise interrupted by dividing lines 43', the dividing lines 1 'and 43' of the two layers of the material composite are offset from each other, preferably by a can circumference. The overlapping areas between in each case a parting line 1 'of the metal strip 1 and the nearest parting line 43' of the carrier tape 43 hold the composite material together so that tensile forces in the material composite can also be transmitted via the parting lines V and 43 '. For this purpose, even small adhesive forces between the carrier tape 43 and its release coating 43a and the pressure-sensitive adhesive layer 42. For the winding of the can coats sections are used, which begin with substantially a circumferential length only carrier tape 43, in the central region substantially a circumferential length together have adjacent carrier tape 43 and metal strip 1 and at the end essentially comprise only a circumferential length of the metal strip 1. Due to the reduced adhesion of the carrier tape 43 to the pressure-sensitive adhesive layer of the metal strip 1, the carrier tape 43 can be detached from the winding mandrel 54 with a built-up suction at 55 suction immediately after the dividing line 43 'from the metal strip 1 and held at the beginning of the winding process at the winding mandrel 54. In the snapshot illustrated with reference to FIG. 20, the winding of the carrier belt 43 begins at a first winding mandrel 54. The winding belt 54 is already wound once around the winding mandrel 54 on the winding mandrel 54, which runs directly clockwise, because the latter correspondingly turns when the turntable 45 moves has turned around its axis. Both the winding mandrel 54 with the incipient wrapping and the once wrapped winding mandrel 54 generates tensile forces in the supplied composite material, so that these winding movements must be coordinated. Because the overlapping area in front of the mandrel 54 with the incipient wrapping is continuously smaller, accordingly, the tensile force is increasingly from this mandrel 54 from. If a higher transmission of the tensile force is desired over the decreasing overlapping area, this can be achieved, for example, with a pressing device arranged directly in front of the winding mandrel 54, in particular with pressing rollers, which presses or presses the metal strip 1 and the carrier strip 43 together so that the frictional forces required for the transmission of the tensile force are increased. Optionally, the winding mandrels 54 are associated with connecting devices with which the inner end of the carrier tape 43 is tightly connected to the adjoining region of the once wound around the winding mandrel 54 carrier tape 43, for example, with the production of a sealing compound by supplying heat and optionally contact pressure. At the earliest after a little more than a complete wrapping of the winding mandrel 54 with the carrier tape 43, the suction force at the suction region 55 can be switched off, but then the holding force necessary for the winding on the winding mandrel 54 would have to be achieved via frictional forces. Preferably, the suction force is turned off only after the complete winding of a can jacket 19. In the situation shown, the second winding mandrel 54 is a dividing line V of the interrupted metal strip 1. Due to the dividing line V, the subsequent portion of the metal strip 1 at the second winding mandrel 54 on the carrier tape 43 adhere and is with this during the further rotational movement of the turntable 45 once the winding mandrel 54 wound so that then at the third winding mandrel 54 shown a Um- winding only carrier tape 1 and a subsequent wrapping carrier tape 43 is present with metal strip 1.

In the further movement to the fourth winding mandrel 54, the winding mandrel 54 shown in the second illustrated by the dividing line 1 'separated end of the metal strip portion 1 is wound onto the winding mandrel 54. So that the loose end of the metal strip 1 is still sufficiently guided, guide elements, preferably guide rollers 56 are arranged between the mandrels. This loose end of the metal strip 1 comprises on the winding mandrel 54 side facing a contact surface 18 'with the pressure-sensitive adhesive layer and on the side facing away from the winding mandrel 54 a decorative surface 17. To a good adhesive bond between the contact surface 18' and the decorative surface 17 preceding To achieve contact surface 18, a pressing device, not shown, is used, which presses the two contact surfaces 18 and 18 'against each other. Pressing devices can be arranged on the turntable 45 at each winding mandrel 54. In another embodiment, the pressing device is arranged outside the turntable, namely in the rotation range of the turntable with the pressing operation.

In the fourth winding mandrel 54, the can jacket 19 is completely wound. In order to be able to remove the can jacket from the mandrel 54, the mandrels 54 preferably comprise a circumferential adjustment device with a smaller circumference for winding the desired can jacket diameters and for removing the can coats. For this purpose, the winding mandrels may comprise, for example, two part-cylinder surfaces divided in the circumferential direction, which are pivotable about an axis parallel to the axis of the winding mandrel relative to one another between winding position and release position. The removal of the can coats 19 from the mandrels 54 takes place at the transfer station 47.

Claims

claims

Method for producing a can body (27) with a can jacket (19) extending circumferentially around a can axis and a can bottom (30), in which process can jackets (19) are produced from flat material regions which are adhesively bonded in the circumferential direction between contact surfaces (18, 18 ') of an overlapping region (20) are closed, and a can bottom (30) is fixed to one end face of each can jacket (19), characterized in that for producing the can coats (19) a strip material (1) with the flat material regions for the can coats (19) in its longitudinal direction by a printing press (2) and continuously printed in printing steps with decorative surfaces (17) and the printed strip material (1) the flat material areas for the can coats (19) are separated, wherein on the strip material (1) at adjacent decorative surfaces (17) the distance between the same boundary lines in a first direction of the Ba In the longitudinal direction or in the transverse direction thereof, a first expansion of the flat material regions in the direction of the can axis and transverse to the first direction of a second expansion of the flat material regions in the direction of the can circumference, namely at least the sum of the can circumference and the width of the overlapping region.

A method according to claim 1, characterized in that the overlap region (20) extends around at least one circumference of the can jacket (19) and thus a strip material (1) is used whose thickness is at most half as large as the desired wall thickness of the can jacket (19 ).

A method according to claim 1 or 2, characterized in that a metal strip is used as strip material (1).

A method according to claim 3, characterized in that the metal strip for forming the adhesive bond of each can jacket at least in each case one of the overlapping region (20) interconnected contact surfaces (18, 18 ') has a pressure-sensitive adhesive layer, wherein when forming the adhesive bond with each other to be connected contact surfaces (18, 18 ') a contact pressure is provided.

5. The method according to claim 4, characterized in that the metal strip (1) has a coherent pressure-sensitive adhesive layer and that on the free surface of the pressure-sensitive adhesive layer, a carrier tape is arranged, which has a release coating in the pressure-sensitive adhesive layer, which is a trouble-free Separating the carrier tape guaranteed by the pressure-sensitive adhesive layer.

6. The method according to any one of claims 3 to 5, characterized in that prior to the printing step for printing decorative surfaces (17) a primer on the metal strip (1) is applied, preferably a under UV irradiation curing primer, optionally an adhesive layer and a printable upper layer.

7. The method according to claim 6, characterized in that the primer with at least one printing forme of the printing press (2) is applied, preferably only in the region of the decorative surfaces (17).

8. The method according to any one of claims 1 to 7, characterized in that at least one of the printing method from the group of offset printing, screen printing and flexographic printing is used in the printing step.

9. The method according to any one of claims 1 to 8, characterized in that at the printing machine (2) on the decorative surface (17) adjoining the first contact surface (18) for the overlap region (20) material for the adhesive bond is applied.

10. The method according to any one of claims 1 to 7, characterized in that the printed strip material (1) in the printing machine (2) along its longitudinal direction in at least two subbands (1a) is divided, each in the transverse direction only the decorative surface (17) for a can jacket (19).

1 1. A method according to any one of claims 1 to 8, characterized in that the flat material areas for the can coats (19) in the printing machine (2) are separated, preferably by means of a punching step.

12. The method according to any one of claims 1 to 9, characterized in that the canned shells (19) on a rotatable winding mandrel (36) are produced, wherein a Flat material portion with a decorative surface (17) and a first contact surface (18) on the winding mandrel (36) is wound, so that the first contact surface (18) in the overlapping region (20) on the second contact surface (18 ') meets, and for forming the Bonding between the contact surfaces (18, 18 ') at least in the overlap region (20) a contact pressure is applied.

13. The method according to claim 12, characterized in that wound before winding a flat material region, a film-shaped inner layer on the winding mandrel (36) and this inner layer is sealed in an overlap region close to a tubular element.

14. can body (27) having a circumferentially around a can axis extending can jacket (19) and a can bottom (30), wherein the can jacket (19) is made of a flat material area in the circumferential direction with an adhesive connection between contact surfaces (18, 18 ') of an overlap region (20) is closed, and a can bottom (30) is fastened to one end face of each can jacket (19), characterized in that the flat material regions of the can jacket (19) consist of a strip material (1), preferably a metal strip (1). 1), which has been guided in its longitudinal direction by a printing machine (2) and has been printed continuously in printing steps with decorative surfaces (17), wherein on the

Band material (1) in adjacent decorative surfaces (17) of the distance between the same boundary lines in a first direction of the strip material (1), namely in the longitudinal direction or in the transverse direction, a first extension of the flat material areas in the direction of the can axis and transverse to the first direction of a second extent of the flat material areas in the direction of the can circumference, namely at least equal to the sum of the can circumference and the width of the overlapping area.

15. can body (27) according to claim 14, characterized in that the overlap region (20) extends around at least a circumference of the can jacket (19) and thus a strip material (1) is used whose thickness is at most half as large as the desired Wall thickness of the can jacket (19).

16. A device for producing a can body (27), characterized in that the device makes a method according to one of the claims 1 to 13 feasible.