EP2700508A1 - Method for printing a wall or floor panel - Google Patents

Abstract

The method involves providing a plate-shaped support (110). The primer layer (120) is applied on to-be-printing surface of the plate-shaped support. The decoration layer (130) is applied on surface portion of primer layer. The liquid radiation-curable mixture of the primer layer is prepared with urethane acrylate. An independent claim is included for decorated wall or floor panel.

Description

The present invention relates to a method for producing a decorated wall or floor panel, and to a panel produced according to such a method.

Such decorated panels are known per se, whereby the term wall panel is also to be understood as panels which are suitable for ceiling clothing. They usually consist of a support or core of a solid material, e.g. a wood material, which is provided on at least one side with a decorative layer and a cover layer and optionally with other layers, for example a arranged between the decorative and top layer wear layer. The decorative layer is usually a printed paper impregnated with an aminoplast resin. The cover layer and the remaining layers are usually made of aminoplast resin.

In certain applications, however, the use of conventional laminate panels based on fiber materials is difficult, for example in areas which are exposed to constant humidity or weathering. This is the case for example in outdoor areas, in damp areas or in special fields of application such as shipbuilding. Here, the influence of moisture can lead to a source of fiber material, both the fiber-based substrate, as well as the decor papers used. Therefore, it is necessary for the application in these areas to provide appropriate moisture and weather resistant panels, for example made of plastic.

However, known plastic pannels show an unsatisfactory decoration, especially if the imitation of a natural material such as wood or natural stone is desired.

It is therefore the object of the present invention to provide an improved method for the production of decorated wall or floor panels.

This object is achieved by a method according to claim 1. With regard to the wall or floor panel, the object is achieved by a panel according to claim 14.

1. a) Bereitstellen eines plattenförmigen Trägers,
2. b) Aufbringen eines Primer zumindest auf eine zu bedruckend Oberfläche des plattenförmigen Trägers,
3. c) Aufbringen eines Dekors durch bedrucken zumindest eines Teils der mit dem Primer behandelten Oberfläche, welches dadurch gekennzeichnet ist, dass als Primer eine flüssige strahlungshärtbare Mischung auf Basis eines Urethanacrylates eingesetzt wird.

The invention thus proposes a method for producing a decorated wall or floor panel, comprising the method steps:

1. a) providing a plate-shaped carrier,
2. b) applying a primer to at least one surface of the plate-shaped carrier to be printed,
3. c) applying a decoration by printing on at least a part of the surface treated with the primer, which is characterized in that a liquid radiation-curable mixture based on a urethane acrylate is used as the primer.

Surprisingly, it has been found that when using a primer based on a urethane acrylate, the disadvantages known from the prior art with regard to the adhesive strength of the applied decorative layer can be overcome.

The urethane acrylate may be present in the form of reactive oligomers or prepolymers in the primer composition. In the context of the invention, the term "reactive oligomer" or "prepolymer" is to be understood as meaning a compound having urethane acrylate units which can be radiation-induced, if appropriate reacting with urethane acrylate polymer with the addition of a reactive binder or a reactive diluent. Urethane acrylates in the context of the invention are compounds which are essentially composed of one or more aliphatic structural elements and urethane groups. Aliphatic structural elements include both alkylene groups, preferably having 4 to 10 carbon atoms, and cycloalkylene groups having preferably 6 to 20 carbon atoms. Both the alkylene and the cycloalkylene groups may be mono- or polysubstituted with C ₁ -C ₄ -alkyl, in particular with methyl, and may contain one or more non-adjacent oxygen atoms. The aliphatic structural elements are optionally connected to each other via quaternary or tertiary carbon atoms, via urea groups, biuret, urethdione, allophanate, cyanurate, urethane, ester or amide groups or via ether oxygen or amine nitrogen. Furthermore, urethane acrylates according to the invention may also have ethylenically unsaturated structural elements. These are preferably vinyl or allyl groups which may also be substituted by C ₁ -C ₄ -alkyl, in particular methyl, and which are derived in particular from α, β-ethylenically unsaturated carboxylic acids or their amides. Particularly preferred ethylenically unsaturated structural units are acryloyl and methacryloyl groups such as acrylamido and methacrylamido and especially acryloxy and methacryloxy.

Radiation-curable in the sense of the invention means that the primer composition is induced by electromagnetic radiation of suitable wavelength, e.g. UV radiation, or electron radiation can be at least partially polymerized.

In addition, the radiation-curable primer used according to the invention can have a photoinitiator. The photoinitiator serves to initiate a radical polymerization of the urethane acrylate or the urethane acrylate oligomers or prepolymers to the corresponding polymer. Suitable photoinitiators are, for example, benzophenone and benzophenone derivatives, such as 4-phenylbenzophenone and 4-chlorobenzo-phenone, 4,4'-bis (dimethylamino) benzophenone, anthrone, acetophenone derivatives, such as 1-benzoylcyclohexan-1-ol, 2-hydroxy-2,2 -dimethylacetophenone and 2,2-dimethoxy-2-phenylacetophenone, benzoin and benzoin ethers such as methyl, ethyl and butyl benzoin ethers, benzil ketals such as benzil dimethyl ketal, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, anthraquinone and its derivatives such as b-methylanthraquinone and t-butylanthraquinone, acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphinate and bisacylphosphine oxides. The photoinitiator may preferably be present in a concentration between ≥0% by weight and ≤15% by weight, more preferably between ≥1% by weight and ≤10% by weight, in the primer composition.

Furthermore, the primer composition which can be used according to the invention, as already mentioned above, can have a reactive diluent. Suitable reactive diluents are, for example, monofunctional or polyfunctional acrylates such as, for example, 2-hydroxyethylmethylacrylate (HEMA), hydroxypropylmethylacrylate (HEPA), hydroxyethylacrylate (HEA), hydroxypropylacrylate (HPA), tripropylene glycol diacrylate (TPGDA), 1,6-hexanediol diacrylate (HDDA), propoxylated glycerol triacrylate ( G3POTA), or pentaerythritol triacrylate (PETIA), trimethylolpropane triacylate (TMPTA), pentaerythritol tetraacrylate (PETA). In this case, the reactive diluent in the primer composition preferably in a concentration between ≥ 1 wt .-% and ≤ 40 wt .-%, more preferably between ≥ 10 wt .-% and ≤ 30 wt .-% may be included.

In addition, the primer composition which can be used according to the invention may contain further constituents, for example UV stabilizers, rheology agents, such as thickeners, free-radical scavengers, leveling agents, defoamers or preservatives. Examples of UV stabilizers are oxanilides, triazines, benzophenones or benzotriazole, which also in combination with radical scavengers such as sterically hindered amines, such as 2,2,6,6-tetramethylpiperidine, 2,6-di-tert-butylpiperidine or their Derivatives, e.g. Bis (2,2,6,6-tetramethyl-4-piperidyl) sebacinate.

It may also be provided in one embodiment of the invention that is used as primer, a composition having pigments or dyes.

In a particularly preferred embodiment of the method according to the invention, a primer composition is used which is substantially free of non-polymerizable solvents. This avoids that any degassing solvent to an impairment of the subsequent auszubringenden decor, for example, by a bleeding of color points lead. Due to the extensive freedom of non-polymerizable solvents emission of solvent is significantly reduced both during the manufacturing process, as well as from the finished wall or floor panel.

The use of radiation-curable primers based on urethane acrylates makes it possible to apply a decoration, for example by means of digital printing technology, immediately following the application and the radiation-induced curing of the primer layer. The primer layer ensures good adhesion of the applied decoration on the carrier surface coated with the primer. In this case, urethane acrylates have the advantage of good adhesion both to the support material and to the decorative layer, ie the decorative color or ink. This is due inter alia to the polymerization reactions occurring in this type of polymers, in which on the one hand a radiation-induced radical polymerization of the OH groups occurs, on the other hand, a post-curing of the polymer via the NCO groups. As a result, a tack-free and workable surface is obtained immediately after the radiation-induced curing, while the final properties of the primer layer are also influenced by the NCO-group-based post-curing and ensure a secure bond to the carrier material. In addition, the postcuring that occurs ensures that sufficient layer stability is achieved even in less or unexposed areas of the support. This makes it possible with the inventive method in particular Even pre-structured carrier, so carrier whose surface already have a three-dimensional structuring, securely provided with primer layer, which ensures that the subsequently applied decor is firmly bonded to the carrier.

In the method according to the invention, the primer can preferably be applied to the carrier plate by means of rubber rollers. Alternatively, an order can be made by means of a casting machine. It may also be provided that the primer is sprayed onto the carrier plate. Depending on the application technique, the viscosity of the primer composition can be adjusted by varying the reactive diluent content in the composition.

The primer is preferably used in an amount between ≥ 1 g / m ² and ≦ 100 g / m ² , preferably between ≥ 10 g / m ² and ≦ 50 g / m ² , in particular between ≥ 20 g / m ² and ≦ 40 g / m ² applied. Following the application of the primer to the carrier surface, irradiation is carried out with a radiation source of suitable wavelength.

According to a preferred embodiment of the method, the radiation-induced curing of the primer by irradiation with a wavelength between 100 nm to 380 nm, preferably between 250 nm and 380 nm, for example by means of a Hg, Ga, or Fe metal vapor lamp. Depending on the production speed and the exposure time resulting therefrom, the radiation power is in a range between ≥50 mW / cm ² and ≦ 30 W / cm ² , preferably between ≥ 0.5 W / cm ² and ≦ 15 W / cm ² . As an alternative to metal halide lamps, LED UV lamps with a suitable emission wavelength can also be used in the method according to the invention. The exposure time may be in a range between 0.1 s and 180 s, preferably between 0.5 s and 60 s, depending on the radiant power.

In one embodiment of the method according to the invention, the decoration is applied by means of printing technology directly to the radiation-induced at least partially cured primer layer. It may be provided that the printing by means of high-pressure process, such as flexographic printing, offset printing, gravure printing, or through printing process, such as screen printing is applied to the primer layer. In particular, it may be provided that the printing of the decor by means of digital printing method, such as inkjet method, is applied. It is preferred regardless of the printing method used that the decor is applied medium radiation-curable inks or inks.

For the purposes of the invention, the term radiation-curable color is understood as meaning a composition containing binders and / or fillers and having color pigments which is induced by electromagnetic radiation of a suitable wavelength, such as e.g. UV radiation, or electron radiation can be at least partially polymerized. For the purposes of the invention, the term radiation-curable ink is to be understood as meaning an essentially filler-free, color pigment-comprising composition which is induced by electromagnetic radiation of a suitable wavelength, such as e.g. UV radiation, or electron radiation can be at least partially polymerized.

According to a preferred embodiment of the invention, it may be provided that a wear and / or cover layer is applied to the decorative layer. It is particularly preferred that also a radiation-curable composition, such as a radiation-curable lacquer is applied to form the wear and / or cover layer. It can be provided that the wear layer hard materials such as titanium nitride, titanium carbide, silicon nitride, silicon carbide, boron carbide, tungsten carbide, tantalum carbide, alumina (corundum), zirconium oxide or mixtures thereof, to increase the wear resistance of the layer. It may be provided that the hard material in an amount between 5 wt .-% and 40 wt .-%, preferably between 15% and 25% by weight in the wear layer composition. The hard material preferably has an average particle diameter between 10 μm and 250 μm, more preferably between 10 μm and 100 μm. In this way, it is advantageously achieved that the wear layer composition forms a stable dispersion and segregation or settling of the hard material in the wear layer composition can be avoided.

To form a corresponding wear layer, it is provided in one embodiment of the invention that the hard material-containing and radiation-curable composition in a concentration between 10 g / m ² and 250 g / m ² , preferably between 25 g / m ² and 100g / m ² applied becomes. In this case, the application can be applied for example by means of rollers, such as rubber rollers or by means of pouring devices.

In a further embodiment of the method according to the invention, it may be provided that the hard material is not present in the composition at the time of application of the wear layer composition, but is scattered as particles onto the applied wear layer composition and this is subsequently cured in a radiation-induced manner.

According to one embodiment of the method, the carrier plate consists of a plastic, in particular a thermoplastic, elastomeric or thermosetting plastic, paper or cardboard. Also plates of minerals such as natural and artificial stone slabs, concrete slabs, gypsum fiberboards, so-called WPC plates (from a mixture of plastic and wood), as well as plates of natural raw materials such as cork and wood can be used according to the invention as a carrier. Also plates of biomass such as straw, corn straw, bamboo, foliage, algae extracts, hemp, oil palm fibers, according to the invention be used. Furthermore, recycled materials from the materials mentioned can be used in the context of the method according to the invention.

The backing sheet material may be solid or have more or less large voids, depending on the desired physical properties of the finished sheet. be foamed or have cavities whose size is of the order of the plate dimensions. It is also possible to use layer structures of a plurality of the stated materials, for example plasterboard or wood-plastic laminated boards.

Preferred as sheet material are thermoplastics such as polyvinyl chloride, polyolefins (for example, polyethylene (PE), polypropylene (PP), polyamides (PA), polyurethanes (PU), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA ), Polycarbonate (PC), polyethylene terephthalate (PET), polyetheretherketone (PEEK) or mixtures or co-polymers thereof The plastics can contain conventional fillers, for example calcium carbonate (chalk), aluminum oxide, silica gel, quartz flour, wood flour, gypsum In particular, it may be provided that the plate material has a flameproofing agent.

In particular, thermoplastics also offer the advantage that the products made from them can be recycled very easily. Recycled materials from other sources can also be used. This results in a further possibility for reducing the production costs.

According to a preferred embodiment of the method, structured carrier plates are used. In this case, the carrier plates have a three-dimensional structuring on at least one partial surface to be provided with a decoration, which, for example, corresponds to the surface structure of a natural material, such as wood, for example. is modeled. The structuring can already be introduced directly during the production of the carrier plate, in which the plate material is extruded, for example, directly structured or the carrier plates are in a subsequent step by suitable means, we structured rolls or punches, structured, this structuring also immediately after can be made by extruding.

In particular, it is preferred that the application of the decoration takes place in accordance with the structuring of the carrier plate, in order to obtain as faithful a replica of a natural material as possible. It may be provided that the structuring of the carrier plate by means of suitable optical methods and an alignment of the pressure tool and the carrier plate to each other in dependence on the detected structuring. For aligning the pressure tool and the support plate to each other, it may be provided that a necessary relative to the orientation relative movement between the pressure tool and support plate to each other by a displacement of the support plate or by a displacement of the pressure tool. According to a further embodiment of the method, it is provided that a structuring of the wall or floor plate after the application of the cover and / or wear layer takes place. For this purpose, it can preferably be provided that a radiation-curable composition is applied as cover and / or wear layer and irradiation with a radiation inducing the curing process takes place only to the extent that only partial hardening of the cover and / or wear layer takes place. In the thus partially cured layer, a desired surface structure is impressed by means of suitable tools, such as a hard metal structural roll or a stamp. The embossing is preferably carried out in accordance with the decor applied to the primer layer. In order to ensure sufficient conformity of the structure to be introduced with the decor, provision may be made for the carrier plate and the embossing tool to be aligned with one another by corresponding relative movements. Following the introduction of the desired structure into the partially cured deck and / or Wear layer is a further hardening of the now structured cover and / or wear layer in particular by further irradiation of the layer with electromagnetic radiation or electron radiation.

According to a further embodiment of the method, it can be provided that at least partial steps of the method are carried out under an inert gas atmosphere. In particular, it may be provided that the process step of applying the decoration is carried out under an inert gas atmosphere. Suitable inert gases are, for example, nitrogen, carbon dioxide, noble gases or mixtures of these.

In addition, the invention relates to a wall or floor panel, comprising a plate-shaped support, a primer layer and a decorative layer, which is characterized in that the primer layer comprises a polyurethane acrylate.

In one embodiment of a wall panel or floor panel according to the invention, the primer layer has a layer thickness between ≥50 μm and ≦ 1 mm, preferably between ≥100 μm and ≥ 800 μm.

According to a further embodiment of the wall panel or floor panel according to the invention, the decorative layer is essentially formed from a radiation-curable ink or ink layer. In this case, the decorative layer, for example, have a layer thickness between ≤50μm and ≤1mm, preferably between ≥100μm and ≤800μm.

On the decorative layer, a cover or wear layer may be applied. It may be provided in particular that the cover or wear layer is formed of radiation-cured paint. The covering or wear layer may, for example, have a layer thickness between ≥ 100 μm and ≦ 5 mm, preferably between ≥ 0.5 mm and ≦ 2.5 μm.

• Fig. 1 zeigt schematisch einen Aufbau eines erfindungsgemäßen Wand- oder Bodenpaneels.

The invention is explained below with reference to a figure and an embodiment.

• Fig. 1 schematically shows a structure of a wall or floor panel according to the invention.

Fig. 1 shows a schematic structure of an embodiment of a wall or floor panel (100) according to the invention. The panel consists of a plate-shaped carrier (110). The carrier (110) consists of an extruded plastic material such as polyethylene (PE), polypropylene (PP), polyamides (PA), polyurethanes (PU), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polymethyl methacrylate (PMMA ), Polycarbonate (PC), polyethylene terephthalate (PET), polyetheretherketone (PEEK) or mixtures or co-polymers thereof. In the carrier (110) are introduced by means of suitable tools a natural wood material modeled surface structures (111). On the plate-shaped support (110), a primer layer (120) is applied, which has a radiation-cured polyurethane acrylate. A decorative layer (130) is applied to the primer layer (120) by means of suitable printing methods, such as digital printing, flexographic printing or offset printing. To increase the wear resistance, a cover layer (140) and / or hard-wearing wear layer (150) is applied to the decorative layer (130), wherein the cover and / or wear layer (140, 150) are in particular formed by a radiation-cured lacquer layer.

example 1

On a plate-shaped surface-structured carrier made of a polyurethane material, a primer composition comprising an aliphatic urethane acrylate prepolymer is applied in an amount of 20-35 g / m ² and irradiated with a mercury vapor lamp at a power of about 3W / cm ² and an exposure time of approx 10s hardened. The primer layer thus prepared is determined in accordance with the structure of Carrier plate applied a decorative layer by means of an inkjet process using a UV-curable ink. Immediately after the ink application of the UV-curable ink, the decorative layer is irradiated with a UV light source of suitable wavelength. After irradiation of the decorative layer and sufficient curing of the same to avoid bleeding or smearing of the applied decoration, there is a stacking of the plates before further processing. Subsequently, a cover and / or wear layer is applied to the decorated support plate, which is formed from a radiation-cured lacquer layer, in which corundum particles are introduced.

Claims (15)

Method for producing a decorated wall or floor panel, comprising the method steps a) providing a plate-shaped carrier, b) applying a primer at least to the surface of the plate-shaped carrier to be printed, c) applying a decoration by means of printing on at least a part of the surface treated with the primer,
characterized in that a liquid radiation-curable mixture based on a urethane acrylate is used as the primer. A method according to claim 1, wherein a mixture based on an aliphatic urethane acrylate is used as primer. A method according to any one of claims 1 or 2, wherein the primer comprises a photoinitiator. Method according to one of the preceding claims, comprising the method step d) applying a wear and / or cover layer to the printed surface, Method according to one of the preceding claims, wherein the printing is effected by means of digital printing. Method according to one of the preceding claims, wherein the printing is effected by means of a radiation-curable ink and / or ink. Method according to one of claims 3 to 6, wherein as a wear layer a hard material-containing radiation and / or thermosetting paint is applied. Method according to one of the preceding claims, wherein a carrier based on thermoplastic material or a wood-plastic composite material (WPC) is provided. A method according to claim 8, wherein a thermoplastic based carrier selected from the group consisting of polyvinyl chloride, polyolefins (e.g., polyethylene (PE), polypropylene (PP), polyamides (PA), polyurethanes (PU), polystyrene (PS), acrylonitrile Butadiene-styrene (ABS), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyetheretherketone (PEEK) or blends or co-polymers thereof. Method according to one of the preceding claims, wherein as carrier a structured plate-shaped material is provided. The method of claim 10, wherein the printing is in accordance with the patterning of the substrate. Method according to one of the preceding claims, wherein the wearing and / or covering layer is structured after the application. The method of claim 12, wherein the wear and / or cover layer is partially cured prior to structuring. Wall or floor panel (100), comprising a plate-shaped carrier (110), a primer layer (120) and a decorative layer (130), characterized in that the primer layer (120) comprises a polyurethane acrylate. Wall or floor panel according to claim 14, wherein the decorative layer (130) is formed essentially of a radiation-curable ink or ink layer.

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