Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/22—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes
  • B05D7/222—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to internal surfaces, e.g. of tubes of pipes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05C7/00—Apparatus specially designed for applying liquid or other fluent material to the inside of hollow work

Definitions

• the present invention relates to a method for coating can seams, a can seam coating system and a can welding system.
• Metal sheets that are intended to be processed into metal containers are first coated or painted on the side that is intended to form the interior of the container. These metal sheets are then bent or folded, for example, to form the container. The respective end edges of the metal sheets bent or folded in this way are joined together and welded tightly together, for example by means of a can welding device, but the existing paint is completely burned and the weld seam is therefore again uncovered. This weld seam is particularly susceptible to corrosion, which is why it must be covered or coated after the welding process by means of suitable coating agents.
• Continuous can seam coating systems e.g. 3. downstream of a welding device on a welding arm are known.
• a coating head is arranged on the same processing arm in the processing direction downstream of the welding head, by means of which the can seam is coated by applying, for example, a wet paint or a powder paint.
• Varnishes require a post-processing section to either evaporate the solvent or water present in the case of wet varnishes, or to retouch the coating to ensure sufficient adhesion to the seam.
• Discontinuously operated can seam coating systems are also known, in which either the cans are moved against a coating head for coating the seam in a coating unit, or vice versa, where the coating head is moved into the can.
• the can seam is coated by means of wet or powder lacquers or a so-called plastisol, in which case coating materials in turn require post-treatment in order to achieve good adhesion to the substrate and a completely covering and technically perfect coating ⁇ to get free coating.
• the mentioned aftertreatment is generally a heat treatment, which is undesirable on the one hand for reasons of energy technology and is also expensive in terms of apparatus, since the can must be guided exactly along such an aftertreatment so that the area of the coated seam is actually actually treated or is post-annealed.
• hot melt material be used for coating can seams, which is also known under the name hot melt or hot melt adhesive.
• hot-melt materials are known in particular from adhesive technology, where they are used for gluing or joining two parts. Hotmelt materials of this type are used in particular in the automotive industry as well as in the textile and packaging industry for bonding in a wide variety of applications.
• the advantage of using a so-called hot melt in the application defined according to the invention is that post-treatment of the seam covered by the hot melt material can be completely dispensed with, since hot melt materials generally have excellent adhesion to the substrate and also have good flow properties due to their large melt viscosity range, but without "dripping" from the seam due to the viscosity being too low.
• the hot melt material of an application or coating device feed in order to be melted onto the can seam shortly before the application or onto the can seam when applying.
• the coating of the can weld seam is carried out immediately after the weld seam has been created, i.e. downstream of a can welding device, in that the coating device for the hot melt is arranged on the same processing arm of the welding system on which the welding device is arranged upstream in the processing direction of the coating device.
• the hot-melt material to be applied can be in powder, rod, wire, film or else in strip form and can be fed to the coating device by means of appropriate transport means.
• thermoplastic polymer such as, for example, a polyester, a copolyester, PVC, polyethylene, polyamide or copolyamide or another polymer, that is commonly used as a hot melt adhesive.
• PVC polyethylene
• polyamide or copolyamide or another polymer that is commonly used as a hot melt adhesive.
• the choice of the hot-melt material to be used lies in the intended use of the can, the can weld seam of which is to be coated. In particular for cans for food or fruit juices D ⁇
• weld seam coating is subjected to particularly high stress, it is also possible to use a polymer which is at least partially crosslinkable. Due to the process control, care should be taken to ensure that the crosslinking of the thermoplastic polymer is triggered by the heat added during application, which in turn means that the coating cannot be retempered.
• the hotmelt material can be melted, for example, directly on the coating device by means of, for example, an infrared radiator, a microwave radiator or a hot air unit or another suitable heating means.
• the melting of the hotmelt material can, however, also take place by heating the can from the outside, by pressing the hotmelt material, which is in solid form per se, onto the weld seam heated from the outside and thereby melting.
• the hot-melt material to be applied can, for example, be fed continuously to the coating device, for example by a processing arm, of a can welding system.
• a can seam coating system is particularly suitable for carrying out the methods defined according to the invention, it having to have at least one coating device which is suitable for the application or application of a hot melt material.
• a melting device is particularly necessary, as well as a coating or application device such as a nozzle, roller, roller, pressure plate or a stripping agent.
• the can seam coating system defined according to the invention is particularly suitable for use in a can welding system.
• Show: 1 schematically shows a can welding and a can seam coating system with supply of the hot melt material through the processing arm
• Either completely flat or at least partially bent open can sheets 2 are fed to a can welding or can seam coating system 1 on an endless conveyor belt 5 in order to be joined or welded along the two free ends.
• the open can bodies 2 are welded on a welding unit 7, which is represented schematically by two rollers.
• the functionality of this welding device is dispensed with, since it is well known from the prior art and does not form part of the present invention.
• the application roller 18 is arranged at the end on a processing arm 10, which processing arm 10 is fastened, for example, to a holder 11.
• the application roll 18 is fed by means of an endless belt 13, which is guided over various deflection rolls 17, the hot melt material provided for the coating.
• the hot melt material 16 can, for example, be applied to the endless belt 13 in film or tape form on a hot melt application roll 15 in order to be fed to the application roll 18 together with the latter.
• the endless belt provided with the hot melt is designated by the number 13a.
• the hot-melt material is transported through the processing arm 10, which is supported by a support roller 21, to the coating device 9.
• a can which is freshly welded to the welding device 7 is then passed to the coating device 9 after the welding process, where the hotmelt material is applied to the freshly created weld seam by means of the application roller 18.
• the hotmelt material can be melted during application by heating the application roll, or it is possible to provide heating units, such as an infrared radiator, on the processing arm, by means of which the hotmelt material is in front of or at Application is melted onto the weld seam.
• heating units such as an infrared radiator
• an endless conveyor belt 5a feeds open, for example already bent, metal sheets 2 to a welding device 7, where the welding seam is produced.
• the can body After the can body has been welded, it is transferred to a further, faster-running endless conveyor belt 5b in order to be guided to the coating device 9.
• This more rapid removal of the can body 3 created creates a distance from the subsequent can body which is still located in the welding device 7, which distance can be used to supply the hot-melt material to the coating device 9 from the outside.
• the coating device comprises an application roller 18 and a counterpressure roller 19 arranged on the outside, but over which an endless belt 24 is now guided.
• This endless belt 24 is deflected on a further guide roller 22 and, before being returned to the counter-pressure roller 19, is coated with, for example, powder or tape-like hot melt material 16a.
• the application roll 18 is coated by the hotmelt material 16a, in each case between two can bodies 3 passing through the coating device 9, which can then serve from the inside for coating the weld seam.
• the entire coating device 9 can be clocked in such a way that the endless belt 24 is always coated with hot melt material 16a when the application roller 18 is subsequently free upwards.
• the coating of the endless belt 24 is interrupted when it is not possible to transfer the hot melt material onto the application roll 18. This prevents the can weld seam from being coated from the outside by means of the hot melt material.
• the melting of the hot melt material can in turn take place in that heating means are provided on the processing arm 10. However, it is also possible to heat the can weld seam from the outside, so that the hot melt material melts when applied to the heated weld seam.
• FIGS. 1 and 2 only serve to better explain the method according to the invention.
• the coating organs to be used, the coating elements can also be selected as desired.
• a coating nozzle can be used, such as is used for example for the application of powder coatings.
• a hot-melt material or a hot-melt adhesive is used for the coating of the freshly created can weld seam. Surprisingly, it has been shown that such materials used for gluing are also suitable for the application described above.

Landscapes

• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Coating Apparatus (AREA)
• Paints Or Removers (AREA)
• Diaphragms For Electromechanical Transducers (AREA)
• Apparatuses And Processes For Manufacturing Resistors (AREA)
• Connection Or Junction Boxes (AREA)
• Electrophonic Musical Instruments (AREA)
• Closures For Containers (AREA)
• Coating With Molten Metal (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)
• Moulding By Coating Moulds (AREA)
• Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)

Priority Applications (1)

Applications Claiming Priority (6)

Publications (1)

Family

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Family Applications (1)

Country Status (18)

Cited By (1)

Families Citing this family (14)

Citations (6)

Family Cites Families (2)

• 1993
  • 1993-04-19 CA CA002094358A patent/CA2094358A1/en not_active Abandoned
  • 1993-04-20 EP EP93106383A patent/EP0603456B1/de not_active Expired - Lifetime
  • 1993-04-20 AT AT93106383T patent/ATE186858T1/de not_active IP Right Cessation
  • 1993-04-20 DE DE59309884T patent/DE59309884D1/de not_active Expired - Lifetime
  • 1993-04-20 ES ES93106383T patent/ES2140423T3/es not_active Expired - Lifetime
  • 1993-04-21 AU AU37045/93A patent/AU3704593A/en not_active Abandoned
  • 1993-04-26 BR BR9301651A patent/BR9301651A/pt not_active Application Discontinuation
  • 1993-04-28 HU HU9301225A patent/HU9301225D0/hu unknown
  • 1993-04-30 NO NO931592A patent/NO931592L/no not_active Application Discontinuation
  • 1993-05-03 IL IL105589A patent/IL105589A0/xx unknown
  • 1993-05-03 FI FI931985A patent/FI931985A/sv unknown
  • 1993-05-07 UY UY23580A patent/UY23580A1/es unknown
  • 1993-05-14 CN CN93105613A patent/CN1060972C/zh not_active Expired - Fee Related
  • 1993-05-17 JP JP5114531A patent/JPH06206045A/ja active Pending
  • 1993-05-31 BG BG97832A patent/BG97832A/xx unknown
  • 1993-12-02 MX MX9307598A patent/MX9307598A/es unknown
  • 1993-12-03 PL PL93301310A patent/PL301310A1/xx unknown
  • 1993-12-23 WO PCT/CH1993/000292 patent/WO1994014546A1/de active Application Filing
  • 1993-12-23 AU AU56916/94A patent/AU5691694A/en not_active Abandoned

Patent Citations (6)

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