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
  • B44C1/10—Applying flat materials, e.g. leaflets, pieces of fabrics
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
  • D21H27/18—Paper- or board-based structures for surface covering
  • D21H27/22—Structures being applied on the surface by special manufacturing processes, e.g. in presses
• • 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

Definitions

• the invention relates to a coating material for the surfaces of panels, in particular wood panels, wood-based panels, plastic panels or panels made from a wood-plastic mixture.
• CPL Continuous Pressure Laminates
• a resin-impregnated decorative paper and a multi-layer carrier paper made of parchment or kraft paper. These individual layers are layered on top of one another and connected to one another by high pressure and high temperature in a hot press.
• the fiber structure of the papers is strengthened.
• a dense material with a closed surface is formed.
• a method for producing a high pressure laminate is, for example, from US Pat EP 3 296 107 A1 known.
• finish foil or coating foil which consists of a paper web treated with a lacquer surface.
• the paint is cured, for example, by UV lamps.
• the paper is not completely penetrated by the lacquer.
• the surface is therefore only slightly scratch-resistant.
• the non-resinous, printed parchment paper and the overlay paper impregnated with melamine resin are unwound from two different rolls and fed to a continuously operating double belt press.
• the surface tension of the non-resinous parchment paper used is designed in such a way that an aqueous ink, as is commonly used in decorative gravure printing, shows poor or no adhesion to the parchment sheet. Therefore, a UV-curable ink must be used.
• the production is associated with a high structural effort. Due to the asymmetrical structure of the laminate, it is subject to a strong tendency to curl, which makes further processing such. B. difficult when coating the plates.
• a coating material is to be created which is characterized by good further processability, on the one hand is as thin as possible and on the other hand has a high abrasion resistance.
• a generic coating material consists of a single resin-impregnated cellulose layer which is provided with a decoration on one side and which is provided with a transparent cover layer covering the decoration.
• This coating material can be referred to as a thin laminate.
• the cellulose layer is preferably designed as a printing base paper.
• the cover layer is preferably made of a radiation-curable acrylate lacquer z.
• B a UV paint, or a mixture of acrylic paint and polyurethane.
• the cellulose layer is preferably designed as a printing base paper with a weight of 60 to 100 g / m 2 , preferably 70 to 90 g / m 2 and particularly preferably 70 g / m 2 .
• the cellulose layer is preferably impregnated with a urea-formaldehyde resin, a melamine-formaldehyde resin, a mixture of urea-formaldehyde resin and melamine-formaldehyde resin or with a polyurethane.
• the cover layer is preferably applied with a roller or a roller. But it can also be sprayed on.
• cover layer is dried before the structure is pressed.
• the cover layer can consist of a radiation-curable acrylate lacquer or of a synthetic resin, preferably a thermosetting plastic, and can be at least partially cured before the application is pressed.
• the cover layer When the structure is pressed, the cover layer then hardens completely.
• the decor can be applied using analog and / or digital printing.
• a water-based digital printing ink is preferably used.
• Based on the weight of the cellulose layer an amount of 50 to 90% synthetic resin is preferably used for the impregnation. 75% synthetic resin based on the weight of the paper is preferably used.
• the decorated and core-impregnated paper preferably has a weight of about 100 g / m 2 .
• the surface of the core-impregnated cellulose layer opposite the decor (underside) can also be provided with a cover layer.
• the cover layer preferably has a weight of 5 to 100 g / m 2 .
• the cover layer particularly preferably has a weight of 10 to 60 g / m 2 and very preferably 30 g / m 2 .
• the drying and / or hardening of the impregnated cellulose layer and also of the cover layer is stopped in good time so that although residual activity remains, the cellulose layer or the printed paper can be rolled up, stacked, stored and / or transported without touching one another Glue layers together.
• the coating material consists of a cellulose layer designed as a printing base paper with a weight of about 60 to 120 g / m 2 .
• the printing base paper In contrast to parchment paper, the printing base paper has an open structure.
• Printing base papers are usually white or beige and therefore already form a good printing base for a decor. Alternatively, however, the printing base papers can also have a solid-color decoration.
• a decoration is printed on an upper side of the printing base paper, preferably in single-pass digital printing using water-based digital printing inks (CMYK or even better CRYK).
• the decorated printing base paper is core-impregnated in a conventional impregnation system. Core impregnation is understood to mean that the structural spaces between the cellulose fibers of the printing base paper are largely filled.
• the core can be impregnated with urea-formaldehyde resin, with melamine-formaldehyde resin or with a combination of urea-melamine-formaldehyde resin or with polyurethane.
• a customary polyurethane for example a thermoset polyurethane, is used as the polyurethane.
• Based on the weight of the paper 50 to 60% synthetic resin is used for the core impregnation. With the core impregnation, the decorated and core-impregnated paper reaches a weight of about 100 g / m 2 .
• a cover layer is then rolled or sprayed, which has a weight of about 5 to 100 g / m 2 .
• the cover layer consists of a conventional acrylate varnish, which is applied by means of high-energy radiation, e.g. B. UV radiation can be partially cured and / or cured. Alternatively, a mix of acrylic paint and polyurethane can be used.
• the printing base paper covered with the partially cured acrylate varnish is pressed in a short-cycle press or a continuous hot press at a pressure of about 30 to 70 N / cm 2 and a temperature of 130 to 200 ° C.
• a pressure of 60 N / cm 2 and a temperature of 150 ° C are set.
• the pressing time is about 0.6 to 2 s / mm (plate thickness). Preferably 1.2 s / mm.
• the temperature in the press is measured on the surface of the press plate.
• the impregnated paper can be rolled up, stacked, stored and / or transported, the drying and / or curing of both the core impregnation and the cover layer is stopped in good time.
• the core impregnation tends to contain only proportions of polyurethane and consists mainly of urea and / or melamine-formaldehyde resin.
• the application of the coating material will then preferably be provided on furniture surfaces. If short-cycle presses are used, it must of course be ensured that they have sufficiently high pressing pressures.
• a structuring of the surface of the cover layer, as it is, for example, in FIG EP 3 296 107 A1 is described.
• the structure generator is then inserted between the press plate and the structure to be laminated. It remains there during lamination and is then peeled off the structured surface. It is particularly preferred to produce so-called nano- or microstructures that facilitate cleaning of the surface of the coating material and also counteract fingerprints, for example (anti-fingerprint).
• fingerprints for example (anti-fingerprint).
• the use of a micro-folding carried out with an excimer radiator has proven to be particularly suitable for the anti-fingerprint effect.
• the micro-folding is based on the following principle. 172 nm radiation forms free radicals in acrylates, which trigger polymerization and crosslinking.
• the depth of penetration of the 172 nm photons into the acrylates is between 0.1 and 0.5 nm, so that only a thin surface layer is cross-linked.
• the shrinkage caused by the polymerization then leads to microstructures.
• a wrinkled skin floats on the liquid film, which is then completely hardened with a second radiation source.
• a mercury UV lamp or an electron gun can be used for this or a long wave excimer lamp at 308 nm can be used.
• the irradiation usually takes place in a nitrogen atmosphere.
• a method for adjusting the degree of gloss of decorative and functional surfaces is, for example, in DE 10 2006 042 063 A1 described.
• High-gloss surfaces can also be achieved if high-gloss press belts or press plates are provided.
• the press belts and / or the press plates can also be structured.
• the structures are preferably implemented at least partially in synchronism with the decoration, the aim being complete synchronism.
• the continuous pressing can be done, for example, with a double belt press, which is used by the Hymmen company for the production of HPL laminates.
• This press works on the isobaric pressure principle.
• the adjustment to the product thickness is done by a fixed lower and an upper, height-adjustable pressure frame.
• cooling zones are installed in the infeed of the double belt presses, which prevent the material from pre-reacting.
• the raw material is pressed by the two circumferential steel belts that run through common heating and pressing zones. In the pressing zones, the surface pressure required for the process is generated against the steel belts and thus against the material by means of gaseous pressure media.
• the thermal energy is generated by a thermal oil system.
• the belt drums and the upper and lower heating plates are brought to the required temperature via separately controllable heat transfer oil circuits.
• the surface pressure in the reaction zone takes place via compressed air cushions, which are applied against the Pressing steel strips. This eliminates the friction between the steel belts and the heating plate.
• the required pressure is built up by high pressure compressors and fed into the double belt press via special pressure controls.

Landscapes

• Laminated Bodies (AREA)

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Applications Claiming Priority (1)

Publications (1)

Family

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Family Applications (1)

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Citations (8)

• 2020
  • 2020-03-20 EP EP20164654.4A patent/EP3882041A1/fr active Pending

Patent Citations (8)

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