Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B44—DECORATIVE ARTS
  • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
  • B44C1/00—Processes, not specifically provided for elsewhere, for producing decorative surface effects
  • B44C1/24—Pressing or stamping ornamental designs on surfaces

Definitions

• the present invention relates to a method for producing a structure on a surface of a flat workpiece.
• Structured surfaces are widespread, for example, in the furniture industry and in the construction industry, for example for the finishing of kitchen fronts, furniture panels and building materials.
• surface finishing especially with a replica of a structure, is common nowadays.
• These replicas of structures can be modeled wood pores, simulated stone surfaces or fantasy structures.
• There are various processes for producing these surface structures that are tailored to the coating process for the surface. Different embossing matrices are used, which are pressed into the surface using melamine pressing, for example, or a structure that is painted onto the surface.
• a paper that has been printed with a wood look is impregnated with a melamine resin, dried and then pressed onto a chipboard in a heating press with an embossing plate. Structures with a depth of approximately 20 ⁇ m to 150 ⁇ m then result on the surface through the embossing plate.
• melamine pressing process there are other processes for coating wood-based panels.
• a wood-based panel is painted, printed and then with a provided with a transparent top coat.
• a structure with a structured topcoat roller Such a procedure is for example in the DE 10 2007 019 871 A1 described.
• the EP 3 109 056 B1 finally describes a method for producing a structure on a surface, in which in a first step the surface of a workpiece to be coated is coated with a liquid base layer and in a second step a structure is created in this still liquid base layer with the help of sprayed, liquid droplets that will be fixed later.
• This process is also comparatively complex and requires elaborately manufactured tools.
• the present invention provides a method for producing a structure on a surface, in which tools available in conventional production systems can be used, and which is sufficiently flexible that when a structure is changed, the respective tool (the roller or the Press plate) must be changed.
• the method according to the invention provides the possibility of producing nanostructures or holographic surfaces on the workpiece surface.
• a structure is produced on the workpiece surface by means of a transfer film, on the surface of which there is an original fine structure.
• a structured surface is to be understood as a three-dimensional structure.
• the structured transfer film consists of a material that is suitable for this purpose, for example thermoplastic.
• the structured transfer sheet used in the method can be made as part of the process of manufacturing the fine structure of the target surface, or a transfer sheet that has been previously made or procured elsewhere that has the desired original fine structure can be used in the method.
• the surface can in principle be any surface of a workpiece, such as a wood surface, a plastic surface, a metal surface or a coated paper surface.
• the target surface can be flat or curved (sheet or roll goods).
• the coating can be a lacquer, a paint or another curable coating.
• Acrylic lacquers are preferred. Lacquers that are UV-curable are very particularly preferred.
• the selected transfer film is placed on the target surface in such a way that its original fine structure is the Touches the target surface while the coating is not yet cured. After the coating has cured, the transfer film is removed from the surface of the workpiece.
• the material of the transfer film that adheres to the target surface creates a copied fine structure that is a mirror image of the original fine structure of the transfer film.
• the height of the copied fine structure produced on the target surface is preferably somewhat smaller in the direction of the normal to the target surface than the height of the original fine structure.
• surface structures with a profile depth of, for example, 100 nm to 500 nm, preferably 100 nm to 200 nm, more preferably 120 nm to 150 nm can be produced without the structures ripping out or flowing.
• haptic structures can also be produced which preferably have a profile depth of 10 ⁇ m to 150 ⁇ m, more preferably, without having to use special profiled rollers for this purpose.
• the fine structure with a profile depth of 100 nm to 150 ⁇ m is embossed into the transfer film using a structured cylinder or a structured sleeve.
• a structured cylinder or a structured sleeve For this purpose, it is not intended that the transfer film is first coated with a curable lacquer, which is then embossed and cures, because with such a procedure there would again be the risk of the structure ripping off or flowing.
• the transfer film can definitely be multi-layered.
• the cylinders or sleeves for embossing the transfer film can be made of nickel, copper or chrome, for example. Exemplary methods for imparting the structured surface on the cylinders or sleeves include electron beam lithography, laser technology, such as the use of pico or nano lasers and engraving, chemical or plasma etching.
• the structure can be transferred to the film, for example, by thermal embossing or ultrasonic embossing.
• Thermal embossing can be done with a roll-to-roll printing machine or by static embossing.
• the structured transfer foils can be transparent or opaque, in particular if the lacquer underneath can be cured by irradiation, such as UV irradiation, as will be explained later.
• the material of the transfer film can be selected, for example, from polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyester, polycarbonate, cellophane.
• Other plastics such as bio-based plastics, e.g. polycactide, cellulose acetates and starch blends can also be used as the material of the transfer film.
• Preferred plastics are cellulose acetates, such as cellulose diacetate or cellulose triacetate.
• composite materials of different foils or foil / paper Composite materials of different foils or foil / paper are also suitable for the transfer foils.
• the connection of two materials to produce a composite material can be done, for example, by gluing using dispersion, LF or LH adhesives, co-extrusion or using ultrasound.
• the film thickness of the transfer film is preferably 10 ⁇ m to 250 ⁇ m. Most preferred is a film thickness between 50 ⁇ m and 90 ⁇ m, so that the transfer film has an advantageous stiffness and yet a sufficient balance between flexibility and stiffness to be used in the method according to the invention.
• the structured transfer film can also have a thermoreactive adhesive layer, for example made of EVA / PE, to improve the rigidity.
• Foil thicknesses between 60 ⁇ m and 80 ⁇ m are preferred for structuring furniture surfaces.
• Foil widths can be from 10 mm to 2500 mm. Foil widths of 800 mm to 2100 mm are provided for structuring furniture surfaces.
• the structured transfer foils can, for example, be applied to the surface of a flat workpiece using commercially available calander coating inert machines, as is practiced, for example, in the furniture industry for the production of high-gloss surfaces.
• Calander coating inert machines of this type are available, for example, from Hymmen GmbH (Hamm, Germany) and Cefla s.c. (Imola, Italy).
• UV lacquers are applied using a roller process.
• a film or tape smooths the still liquid paint surface. The curing takes place through the film by means of UV radiation with direct surface contact. The film is then removed from the surface. It is not necessary to adapt the calendar coating inert machines.
• the flat workpiece as a format or rolled goods can be chipboard, MDF boards (e.g. for furniture), HDF boards, raw chipboard, veneer, paper, floors, interior and exterior cladding and in the cement fiber boards, but also aircraft, automotive, railway parts.
• MDF boards e.g. for furniture
• HDF boards raw chipboard
• veneer, paper e.g. for paper
• floors interior and exterior cladding
• cement fiber boards e.g. for furniture
• aircraft, automotive, railway parts e.g. for furniture
• test marks such as holograms or hidden security features based on micro- or nano-fonts or images, which can facilitate the identification of counterfeit products.
• the method according to the invention can also be used to produce decorative optical or haptic effects on the surfaces of the workpieces.
• Transfer effects can be applied over the whole area or partially.
• the coating applied to the surface of the flat workpiece is preferably a thermal and / or UV-curing lacquer or a thermal and / or UV-curing paint. If a UV-curing lacquer is used, the film is preferably transparent, so that curing with UV light is facilitated.
• Conventional varnishes or paints based on polyacrylate or those based on alkyd resins are preferred.
• the lacquers or paints can be those with or without electrical conductivity. The conductivity can be established, for example, by mixing with polyanilline in the paint composition. Polyaniline is a polymer with excellent electrical conductivity, which has an anti-corrosive effect due to its passivation. If biodegradability is desired, varnishes based on vegetable oils can also be used Find. In principle, there are no limits to the use of certain paints in the process according to the invention.

Landscapes

• Shaping Of Tube Ends By Bending Or Straightening (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

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Applications Claiming Priority (1)

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Citations (7)

• 2019
  • 2019-07-19 EP EP19187327.2A patent/EP3766703A1/fr not_active Withdrawn

Patent Citations (7)

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