Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/0041—Digital printing on surfaces other than ordinary paper
  • B41M5/0047—Digital printing on surfaces other than ordinary paper by ink-jet printing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
  • B41M5/0041—Digital printing on surfaces other than ordinary paper
  • B41M5/0064—Digital printing on surfaces other than ordinary paper on plastics, horn, rubber, or other organic polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M7/00—After-treatment of prints, e.g. heating, irradiating, setting of the ink, protection of the printed stock
  • B41M7/009—After-treatment of prints, e.g. heating, irradiating, setting of the ink, protection of the printed stock using thermal means, e.g. infrared radiation, heat
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B44—DECORATIVE ARTS
  • B44C—PRODUCING DECORATIVE EFFECTS; MOSAICS; TARSIA WORK; PAPERHANGING
  • B44C5/00—Processes for producing special ornamental bodies
  • B44C5/04—Ornamental plaques, e.g. decorative panels, decorative veneers
  • B44C5/0469—Ornamental plaques, e.g. decorative panels, decorative veneers comprising a decorative sheet and a core formed by one or more resin impregnated sheets of paper

Definitions

• the invention relates to a method for producing a digitally printed flat, web-shaped or plate-shaped workpiece, for example a kitchen worktop, a furniture front or a laminate floor part with a decorative and resistant surface.
• inkjet printing process Inkjet printing process
• inkjet jerk process the inkjet printheads used are very difficult to handle in industrial production with UV-crosslinked water-based inks.
• the object is achieved by a method with the Merkmaien of claim 1.
• a digitally printed flat, web-shaped or plate-shaped workpiece with an abrasion-resistant surface is produced as follows:
• Anschiuss is followed by feeding a printable workpiece to the printing device.
• a digital ink-jet printing method which uses an acrylate-containing radiation curing ink.
• a certain minimum penetration depth of the ink is achieved in the paper.
• the printing is followed by hardening of the printing ink by irradiation.
• the cured acrylate layer initially acts as a kind of barrier layer compared to conventional aqueous resin solutions.
• a detachment of the printed workpiece from a material layer, e.g. a backing plate, can be prevented by impregnation with a wetting agent-containing resin mixture.
• the impregnation of the printed workpiece with a resin mixture can be done, for example, by soaking, wetting or spraying the workpiece with the respective resin mixture.
• a wetting agent additive is used, which only allows a penetration of the resin mixture or melamine resin through the acrylate layer in the predetermined paper depth.
• a wetting agent various chemical substances can be used, in particular surfactants.
• the curing of the resin mixture takes place, for example, in the case of aminoplasts by crosslinking polymer strands as a result of a condensation reaction known per se with the aid of a heating press, preferably a short-cycle press or a double-belt press.
• a heating press preferably a short-cycle press or a double-belt press.
• the method according to the invention makes it possible to produce a workpiece with a resistant surface and a layered structure, in which a permanent connection of the individual layers is ensured. This is achieved by a wetting agent-containing resin mixture, which penetrates the workpiece surface much better than conventional resin mixtures, for example, when using a decorative paper as a workpiece, it may come to a complete penetration of the paper.
• the then dried impregnated paper is cured in a hot press.
• wetting agent-containing resin mixture with a wetting agent content of 0.02-2% by weight, preferably 0.1-0.5% by weight, based on the total weight of the wetting agent-containing resin mixture, since this proportion of wetting agent provides optimum penetration of the resin mixture is achieved in the surface of the workpiece, without affecting the transparency or the optical coloring of the resin layer.
• Ais surfactants or surfactant mixtures can advantageously be used as wetting agents. These wetting agents reduce the surface tension between the printed workpiece and the resin used in the impregnation and thus cause a sufficient impregnation of the printed by the process according to the invention workpiece with the resin mixture.
• UV radiation radiation in the ultraviolet range: 1-380 nm. This radiation is contained in the sunlight and thus easily available. UV lamps with a UV radiation range can also be used. It is UV Radiation easy to handle. Other radiation ranges can be used for curing.
• the rate of curing can advantageously be accelerated if the printing inks have photoinitiators which accelerate polymerization or crosslinking of the acrylate units.
• the digital printing using at least one UV-curing printing ink takes place, comprising at least a penetration depth of 10 ⁇ ⁇ ⁇ in a zeliulose ambiences workpiece.
• the UV-curing printing ink is only partially crosslinked during curing by a correspondingly lower radiation dose, preferably from 20 to 80%, particularly preferably from 30 to 65%. This allows a multi-color printing process to be split. Thus, after the printing of two colors, a first curing (pinning) of these colors can first take place. Then two more colors can be applied.
• one or more unprinted material layers which are provided with the wetting agent-containing resin mixture, above and / or below the printed workpiece are arranged so that the flow of resin from these layers of material impregnates the non-resinated, printed workpiece during the pressing process.
• both material layers and the workpiece for example, consist of absorbent materials such as paper.
• the workpiece can be applied to one or more layers of material, which are then joined together by pressing.
• an impregnated and printed decorative paper on a wood-based panel, preferably a chipboard, MDF or HDF board, are applied, whereby a lamination of a bending resistant substrate.
• a subsequent pre-drying of the resin mixture takes place. As a result, a pre-crosslinking of constituents of the resin mixture can be achieved, so that optionally a further impregnated material layer or a further impregnated and printed workpiece can be applied to the resin layer.
• an elamine resin-based and / or phenolic resin-based resin mixture is used, as this material can penetrate the workpiece under pressure and in an underlying material layer, such as a fiberboard, penetrate and after the curing of the resin mixture insoluble Connection with the material layer is received.
• meiamin resin is resistant to moisture after curing.
• melamine is a resin which gives a paper a transparent or translucent appearance
• phenolic resin is an optically colored resin.
• the curing of the resin mixture is carried out by a continuous double belt press.
• This press allows both the processing of continuous material and piece material with a high processing speed.
• the double belt press further, non-printed, impregnated material layers, especially paper layers are pressed with the printed and impregnated workpiece. Since the feeding of the material layers can be made as continuous material, the double belt press offers a higher throughput than, for example, a short-cycle press due to its continuous operation. Subsequently, the further processing of the material, for example by structuring the surface done.
• FIGS. 1-11 show:
• Fig. 1 Schematic representation of three inventive
• Fig. 2 Schematic representation of a method step E) according to the invention
• Fig. 3 Schematic representation of two process steps E) and F) according to the invention
• Fig. 4 Schematic representation of two alternative process steps E) and F) according to the invention
• FIG. 6 shows a schematic representation of the layer sequence of a further embodiment variant of a workpiece produced by the method according to the invention.
• FIG. 7 Schematic representation of the layer sequence of a further embodiment of a workpiece produced by the method according to the invention.
• FIG. 9 shows a schematic representation of the layer sequence of a further embodiment of a workpiece produced by the method according to the invention.
• 10 shows a schematic representation of the layer sequence of a further embodiment variant of a workpiece produced by the method according to the invention;
• FIG. 11 shows a schematic representation of the layer sequence of a further embodiment variant of a workpiece produced by the method according to the invention.
• FIG. 1 schematically shows feeding by means of a feed unit 102, printing of a decorative paper 3 by means of a digital printing unit 103 and curing of the printing inks by means of an irradiation unit 104 in the decorative paper by a printing device 1.
• the digital printing can i.a. take place directly on a wooden surface 20 or, as shown by way of example in FIG. 1, onto a decorative paper 3 unwound from a roll 2.
• the printing device 1 to a printer 4, which has four printheads 5.
• These give according to the invention from UV-curable ink 6 on the surface of the decorative paper 3 from.
• a monochrome or multicolor printing of the workpiece is possible.
• the decorative paper 3 can be rolled up for storage on a roll 8.
• the manner of feeding a workpiece depends on its material properties. Paper sheets can be clamped and unrolled, while wood-based panels are fed on treadmills of the printing device.
• the printheads 5 can be arranged stationarily in the printer 4 in order to realize a single-pass printing process.
• the print heads can advantageously extend over the entire width of the area to be printed.
• the individual print heads have, for example, a width of 70 mm and are next to each other in a printing module, preferably with the UV-curing printing inks. black, mangenta, cyan and yellow.
• the inks may include, for example, acrylate prepolymers, color pigments and photoinitiators. If several printing modules are arranged side by side, it is also possible to print workpieces, for example with a width greater than 1 m. The arrangement of several printing modules stationary next to each other allows a uniform multi-color print image on which no transitions between the individual printing modules can be seen.
• the printheads 4 in the arrangement can also be arranged on a carriage, so that a printing of the workpiece can be carried out in the multi-pass method.
• the above-described stationary and movable printhead assembly may also be arranged in a multi-row succession to achieve a higher printing speed compared to a single-row arrangement.
• nozzle bars may also be arranged.
• Fig. 2 shows the process step of impregnating the workpiece with a wetting agent-resin mixture 19 through an impregnation unit 105, e.g. with an amino resin (melamine resin mixture) which, for example, comprises 0.3% by weight of a surfactant.
• the surfactant lowers the surface tension of the barrier layer of the UV-cured ink 6, so that the resin can penetrate this layer.
• the previously printed decorative paper 3 is unwound from the roll 8, drawn through a resin bath 9 with the liquid netzstoffhal- term resin, squeezed off excess resin by means of a squeegee 10 and then dried by a dryer 11 shown schematically.
• This dryer 1 is designed such that it allows drying of the resin.
• the dryer 11 may be formed as a circulating air or hot air dryer. After drying the resin, the workpiece can be wound up for storage on another roll 2.
• FIG. 3 shows, as an alternative to impregnation, the method step of arranging two unprinted paper layers 17 through a coating unit 107, which is impregnated with a wetting agent-containing resin mixture 19, above and / or below a printed Hoiz workpiece 20.
• the curing of the resin mixture takes place in a curing unit 107.
• the bonding of the individual layers with the respective printed workpiece takes place in a heating press.
• a heating press 106 a double belt press 14 with two rollers 15 and a feeder for the Holztechnikstoffpiatte 13 is shown.
• FIG. 4 An alternative embodiment of the method step of connecting the printed decorative paper 3 with the wood-based material plate 13 by a heating press 106 is shown in Fig. 4.
• FIG. 5 shows the schematic structure of a device for producing the mechanically perforated decorative paper.
• the non-resin decorative paper 3 is unwound. It then passes under a printing device 1 and a UV lamps 7 for drying through and is then equipped with a spike or similar mechanical perforation roller 24 and a correspondingly configured counter-roller 25, in a possible embodiment, the spines of the spiked roller 24 in each case run out executed recesses of the platen roller 25 and so perforated between two rolls already printed decorative paper 3 perforate. Subsequently, the perforated and printed decorative paper 3 is wound up on a roll 26 again. In an alternative embodiment, this decorative paper may also be slightly or more strongly dented before unwinding from the roll 23.
• FIG. 1 shows the schematic structure of a device for producing the mechanically perforated decorative paper.
• the surface of the paper 3 is more or less covered by the printing ink 6.
• a very bright decor which results in the inventive method to a printing with about 3 g of printing ink / m 2 surface area
• a high permeability of the printing ink 6 for the wetting agent-containing Meiaminharzgemisch 9 is given.
• a dark decor which leads to an occupancy of the surface with usually 10 g or more per m 2 surface
• a poorer permeability is given, which would be given according to the prior art without the inventive method no permeability.
• the resin bath 9 with the Meiaminharzgemisch indicates the subsequent post-printing impregnation in which the melamine resin penetrates through the applied ink layer of digital printing ink in the paper.
• Figure 7 shows a cross section through a printable paper 3, which is already printed with the ink 6, and then after the process step of impregnation with Netzhaitigen Meiaminharzgemisch 19. It can be seen that here the Meiaminharzgemisch with the wetting agent additive through the layer of digital ink through penetrated into the paper 3 and this was completely impregnated.
• FIG. 8 shows a section of the layer-wise coated workpiece from the printable paper 3, which has been printed with the digital printing ink 6 and which has been impregnated with meiamin resin mixture 19 containing wetting agent.
• the workpiece made of paper 3 with a wood material plate 13 was provided as a support plate, which was firmly and permanently connected to the paper 3 in the process step of hot pressing. It is important that in the process step of hot pressing the wetting agent Meiaminharzgemisch, which is penetrated in the step of impregnation in the paper 3, penetrates from the paper 3 in the surface of the wood-based panel 13 and cures there and thus forms the connection.
• Resin 19 may contain a corresponding embossed surface structure, which are produced by the use of embossing plates in a short-cycle press or embossing bands in a continuous double belt press.
• this surface structure 27 can be formed by a further resinated paper without decorative printing, that is to say an overlay paper 17. This overlay paper 17 is connected and patterned in the same pressing process with the printed piece of paper 3.
• FIG. 9 shows a basic structure for a possible variant of the method according to the invention, in which a paper 3 preimpregnated with melamine (without wetting agent) is printed with the UV printing ink 6.
• a wetting agent is applied to the UV printing, e.g. sprayed.
• Under the printed prepreg is placed another resinated but unprinted underlay paper 17 'and this coated paper 3 is coated with a wood-based panel 13, e.g. Span- or MDF support plate provided.
• the underlying structure on the back of the support plate can be constructed identically to the structure above.
• the package thus formed is then pressed in a hot press and thus inseparably connected to each other (not shown in Figure 4).
• FIG. 10 shows a further alternative embodiment of the method according to the invention.
• the decorative paper 3 is unmanaged, i. not impregnated, but printed as in the other variants with the UV-curable ink 6.
• the package to be subsequently pressed is additionally formed from an overlay paper 17 impregnated with melamine resin mixture and an appropriate admixture of wetting agent 28 and an underlying underlay 17 also impregnated with melamine resin 19 and wetting agent mixture 28.
• FIG. 11 shows a further alternative embodiment of the method according to the invention.
• the printing with the UV ink 6 on the decorative paper 3 may be before or in an alternative embodiment, even after the mechanical production of the holes (perforation) in decorative paper.
• Through these holes can during during the subsequent pressing process in the hot press penetrate the melamine resin 19 from the impregnated underlay 17 and overlay 17 'better through the ink layer of UV ink 6 and make a complete solid connection.
• the melamine resin with or without wetting agent has completely soaked the mechanically perforated decorative paper 3 and also the uppermost layer of the wood-based material carrier plate. This so-pressed structure is shown.
• a wear protection layer may be applied, possibly also in conjunction with wear layer 21 sprinkled during the curing, in particular with corundum (Aiuminium oxide (Al 2 O 3)).
• a digital data record for a decorative image to be printed for example a wood optic, such as e.g. an oak decoration or the like, for the digital printing apparatus, for example, by a computing unit 101.
• a suitable printable workpiece is fed to the printing device via a feed unit 102.
• This workpiece may be formed as decorative paper 3 or wood-based panel 20
• a decorative paper 3 is preferably a paper having a basis weight of 40-100 g / m 2 , more preferably 60-100 g / m 2 , and a residual moisture before printing 0.5-8% (weight percent) of water in the paper, more preferably 1.5-2.5% (weight percent).
• the decorative paper consists of fibers, for example natural fibers and additives and bleaching agents, for example titanium dioxide (T1O2) for whitening.
• this decorative paper provided is printed in the digital printing device (103) with a UV-curing printing ink.
• This digital printheads are used, which have a nozzle opening size of 10 - 100 pm, more preferably 15 - 40 m in diameter.
• at least one printhead per color that is, four Color print at least four printheads, provided in the device.
• a plurality of print heads per color may also be arranged in the printing device in order to achieve a greater printing capacity.
• the digital printheads may be fixedly disposed over most or all of the width of the media to be printed. In this case, the paper moves under the fixed print heads.
• the UV ink used contains pigments as colorants, ie solids which have a high to very high color stability.
• This color stability according to the known Woll scale, is between 5 and 8, more preferably 6-8.
• the pigments used have an average particle size of 0.01 to 5 ⁇ m, more preferably 0.1 to 3 ⁇ m.
• the proportion of the pigments based on the total weight of the radiation-curing digital printing ink used is 0.4-25%, particularly preferably 1-10%.
• hardening, ie polycrystallizing, acrylates are provided. These are already present as polymers or prepolymers and as a mixture with monomers which have a lower viscosity and act as a reactive diluent. These acrylates, ie polymers and monomers, form the main constituent of the radiation-curing UV printing ink.
• photoinitiators with a percentage by weight of 0.1-25%, more preferably 1-10%.
• photoinitiators e.g. Triaryl sulfonium Saize or with diaryl-iodonium salts in question.
• photoinitiators which represent a different reaction rate at different wavelengths of UV radiation used.
• additives which positively influence the physical properties of the printing ink (viscosity, electrical conductivity, stability, homogeneity).
• a Penetration depth of the UV ink in the decorative paper of 25 - 80%, particularly preferably 40 - 70%, based on the total thickness of the decorative paper.
• a slightly reserved decorative paper e.g. with a melamine resin mixture used.
• the proportion of melamine resin after drying is 2-3%, preferably 5-15% (weight percent).
• a penetration depth of the UV ink based on the total thickness of the paper of 10 - 50%, more preferably 15 - 40%, is produced.
• the decorative papers used have a thickness of 60-300 gm, more preferably of 80-200 ⁇ .
• the decorative paper thus printed is passed under a UV radiation source of a UV irradiation unit 104 and thus the UV ink is cured, ie there is a crosslinking of the acrylates contained in the UV ink instead.
• This crosslinking can be complete, but in an alternative embodiment, it can also be carried out to 50-95%.
• the sources of radiation for the process according to the invention are both UV LEDs and conventional UV emitters, each with an emission maximum between 150 and 380 mm, that is, depending on the selected photoinitiators in the UV-A, UV-B or UV-C range, in question.
• the decorative paper printed and cured according to the invention is subsequently perforated in a mechanical process, ie provided with small holes which likewise ensure improved penetration of the melamine resins subsequently used in the impregnation.
• This perforation can take place, for example, with a chopper roll or similar mechanical instruments.
• the diameter of the perforation holes in the paper according to the method of the invention between 1 and 0.01 mm, more preferably between 0.5 and 0.05 mm to choose.
• the perforation holes are made according to the invention The method is chosen so that after the compression step, there are no more holes left visible (viewing distance 0.5 - 2 m).
• the spacing of the holes in the method according to the invention is between 0.1 mm and 10 mm, preferably between 0.5 and 3 mm (in each case from one hole to the next).
• the thus printed and cured decorative paper is impregnated in an impregnation unit 105 with an aqueous melamine resin mixture.
• Crosslinkable aminoplastic resins are used according to the process of the invention.
• condensation products ie etherified products of melamine, urea-formaldehyde mixtures or melamine-formaldehyde mixtures are used.
• a hardener usually 0.01-2.5% (weight percent) based on the final resin mixture.
• curing agents come e.g. organic sulfonic acids or carboxylic acids are used.
• This aqueous resin mixture with a solids content of 40-70% based on the aqueous solution is then a wetting agent in a concentration of 0.02 to 2% based on the total weight, particularly preferably 0.1 to 0.5%, added.
• Wetting agents by the process according to the invention may be anionic or cationic surfactants.
• anionic surfactants e.g. Sodium, potassium, almonium salts of sulfonic acid, sulfonated fatty alcohols or ethoxylated fatty alcohols are used, as cationic surfactants in an exemplary embodiment e.g. Polyethylene glycol or polyvinyl alcohol.
• wetting agents reduce the surface tension between the printed decor paper 3 and the resin used in the impregnation and thus cause a sufficient impregnation of the decorative paper 3 printed by the method according to the invention with the resin mixture 19.
• the printed and cured with UV rays decorative paper 3 may remain unimpregnated and only a blank overlay 17 and / or an unprinted underlay 17, so a white, later after pressing transparent paper, impregnated with the illustrated aqueous resin mixture and the wetting agent additive.
• the overlay 17 and underlay paper 17 "is arranged on the surface of the decorative paper 3 by a coating unit 107.
• the added wetting agent achieves good resin flow from the overlay and / or underlay paper 17 into the non-resinated but with the UV Ink 6 printed decorative paper 3 during the pressing process in a hot press.
• a package structure is formed from a wood material carrier plate 13, which is covered on one or both sides with the printed and impregnated decorative paper 3,
• the wood-based panel 13 is covered with the printed but not impregnated decorative paper 3, wherein between
• Decorative paper and wood material plate is still a mixed with resin mixture and wetting agent underlay paper 17 is placed.
• an overlay paper 17 impregnated with resin mixture and wetting agent may be applied to the package thus formed.
• the same package formation can be placed on the underside of the wood-based panel.
• This so composed of different layers package is then in a hot press 106 under a pressure of 20 - 60 bar, more preferably 30 - 40 bar, and a temperature of 150 - 230 ° C, more preferably 170 - 200 ° C, pressed.
• smooth or structured embossing plates 110 can be used, which process or structure the surface of the formed package.
• the aqueous dried resin mixture becomes liquid within the first few seconds and then forms a completely soaked composite between the various paper layers and the uppermost cover layer in the wood-based panel (chipboard, MDF or HDF board).
• the further seconds of pressing which usually takes between 5 and 30 seconds, hardens the melamine resin and forms an irreversibly cured, highly resistant surface.
• the top or one of the top impregnated but not printed papers may additionally be provided with a corundum 21 (Al 2 O 3 ) or other solids to increase the abrasion resistance of the product being produced, eg for use as laminate flooring.
• a corundum 21 Al 2 O 3
• other solids to increase the abrasion resistance of the product being produced, eg for use as laminate flooring.
• a continuous double belt press 14 with a corresponding embossing belt usually a chromed steel belt, are used.

Landscapes

• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Thermal Sciences (AREA)
• Toxicology (AREA)
• Laminated Bodies (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=43533091

Family Applications (1)

Country Status (5)

Cited By (2)

Families Citing this family (7)

Citations (3)

• 2009
  • 2009-09-23 DE DE102009044092A patent/DE102009044092A1/de not_active Withdrawn
• 2010
  • 2010-09-21 PL PL10763637T patent/PL2367691T3/pl unknown
  • 2010-09-21 EP EP10763637A patent/EP2367691B1/de active Active
  • 2010-09-21 WO PCT/EP2010/063862 patent/WO2011036142A1/de active Application Filing
  • 2010-09-21 ES ES10763637T patent/ES2414932T3/es active Active

Patent Citations (3)

Also Published As

Similar Documents

Legal Events