RU2780737C2 - Surface suitable for etching - Google Patents

Abstract

FIELD: building materials.

SUBSTANCE: invention relates to a method for the production of a color-changeable decorative surface, which can be easily changed in its color execution by an end user, and which is economical and durable, wherein its is provided that at least one layer of covering material is applied, which provides a possibility of absorption of pigment particles.

EFFECT: obtaining a surface suitable for etching.

18 cl, 1 dwg, 6 ex

Description

The invention relates to a method for producing a color changeable decorative surface according to claim 1 of the claims, and to a material with a color changeable decorative surface according to claim 16 of the claims.

Decorative surfaces made of synthetic resin or lacquer are well known and are, for example, used on floor coverings, wall coverings, ceiling linings or furniture. They have a decorative layer which includes paper with a decorative pattern printed or a decor printed on an underlayer. A protective layer can usually be placed on the decorative layer. In addition, it is known to provide the surface with a structural decor, which is embossed into the surface, for example. Placed on top of the decor layers are at least translucent so that the viewer can perceive the decor.

The disadvantage is that subsequently it is hardly possible to influence the color design of such surfaces. In particular, with such surfaces made of synthetic resin or lacquer, an individual color design of the surface, such as is achieved, for example, with natural wood by etching the surfaces, is no longer possible for the end user.

However, it is in the North American environment that there is an increased need for decorative surfaces that can subsequently be color-coded by the end user himself, while the own decorative structures remain visible and only the color tone needs to be coordinated. Such surfaces that can be subsequently changed in color by the end user could have hitherto been created exclusively with natural wood surfaces, for example, as in the case of solid wood or also wood veneer.

Thus, the invention is based on the problem of providing a method for producing a decorative surface and a material with a similar decorative surface, which can be changed in a particularly simple way by the end user due to its color scheme, and is particularly economical and durable.

The invention solves this problem by means of a method with the characteristics of paragraph 1 of the claims and a material with the features of paragraph 13 of the claims. Preferred embodiments of the invention are given in the dependent claims. In this case, all the described features alone or in any combination, in principle, constitute the subject of the invention, regardless of their generalization in the claims or their relationship in the dependent claims.

The process according to the invention for producing a color-variable decorative surface includes the steps of: obtaining ready-to-use fully cured synthetic resin or lacquer comprising a decorative surface on a carrier layer, applying at least one layer of coating material, drying and curing the layer of coating material.

With conventional hardened decorative surfaces made of synthetic resin or lacquer, it is no longer possible to introduce colored pigments into the layer. In extreme cases, colored pigments may be applied to the surface. Therefore, the finished decorative surface with a layer of coating material obtained according to the invention contains an additional coating that forms a new surface, as a result of which a particularly simple subsequent color matching (hereinafter also referred to as etching), which is otherwise known only when etching solid wood surfaces, becomes possible. . Subsequently applied colorants (colour pigments) adhere to the additional coating or, respectively, are attached to the coating, for example by chemical bonding, and color it. Although a layer of coating material has been applied to the decorative surface, the good technical properties of, for example, the former synthetic resin surface or the lacquer surface remain virtually unchanged. But in addition, a protective layer (fixing layer), for example, a varnish layer, can be applied to the layer of coating material and coloring matter from the stain.

The decorative surface has a decorative print (hereinafter also referred to as decor) which is printed on the upper side of the carrier layer. Thus, the décor may show, for example, the structures of the décor. In particular, the décor is, for example, wood textures, stone textures, stone décor, ceramic tile décor or also fantasy décor. In this case, the decor can be executed as a colored decor, a decor in gray tones or also a black and white decor. In addition, the decorative surface includes a transparent protective layer, which, for example, can be made as a transparent lacquer layer placed on top of the decor or as a transparent synthetic resin layer, for example, as a transparent synthetic resin-impregnated coating. Alternatively, for example when using an impregnable carrier layer, the protective layer can also be formed with a cured and completely dried impregnating carrier layer. As impregnating agent in the sense of the invention are considered, in particular, impregnating materials based on synthetic resin, but, of course, also based on varnish.

The décor in the ready-to-use state is visible to the observer and remains visible in the future after the application of a layer of cover material and subsequent application of a coloring agent (mordant). Accordingly, the cover material layer is also made transparent.

For example, with the decorative surface according to the invention, the general imprint of the ready-to-use decorative surface created by itself with the light printed decor can be darkened, for example by using a dark mordant. That is, the applied coloring matter (color pigment) produces a dark coloration of the surface, whereby at least the practically transparent layer also remains practically transparent, and the printed decorative structure can still be seen.

The possibility of changing the color is understood to mean that the overall color impression predetermined by the decorative printing on the carrier layer can subsequently be changed individually by adding a coloring agent to the layer of the cover material. The subsequent color change may be carried out during industrial production, or alternatively afterwards, for example, by a skilled worker on the article or by the end user himself. Usually carried out by applying a layer of coating material to the entire decorative surface, the contractor himself can decide whether to change the color of the entire decorative surface or only part of it.

As already mentioned, when the color changes, the decorative structures preferably remain visible as before, and as a result of the color change, only the basic color tone of the decorative surface changes again. As a result, extremely high individualization is possible, for example, by each end user. A manufacturer of decorative surfaces can also offer his overall old portfolio with a clearly expanded variety of colors, and also offer particularly simple and economical small series with smaller runs. Already existing structural decors, ie structured surfaces (three-dimensional surfaces), also remain the same, since the coating material layer is applied so thin that it reproduces the existing surface structures. In addition, with structured surfaces, the effect of a three-dimensional surface can be achieved by etching, i.e. changing the color tone, for example, when decorating wood in the area of structurally formed pores (recesses in the 3D structure), more mordant accumulates so that after etching also more color pigment from the stain remains in this area.

In this case, the color matching of the decorative surface can be carried out with the same mordant, for example, with a water-based stain, an oil-based stain or a solvent-based stain, as in the same devices as in conventional etching of wood surfaces.

In connection with the invention, by the surface of a synthetic resin is meant a resin system in which the complete curing of the resin used for impregnating and/or coating, if necessary, has been carried out under the influence of heat and an additionally applied pressure (higher than atmospheric pressure), for example, in short cycle press or continuous press. For example, synthetic resin surfaces may include urea-formaldehyde resin, phenolic resin, but preferably melamine resin.

In the context of the invention, a lacquer surface is understood to be a resin system in which at least the outer layer of a ready-to-use decorative surface is a lacquer surface. Complete curing of the lacquer surface is carried out without the application of pressure (i.e., at most atmospheric pressure), and solely under the action of heat, UV radiation, electron beam irradiation, or high frequency radiation. In particular, the lacquer surfaces can be made as an acrylate lacquer or a polyurethane (PU) lacquer, which are, for example, UV curable.

The decorative surface can be single or multilayer. Thus, for example, the decorative surface can be formed by a synthetic resin-impregnated decorative paper. Here, the paper printed on the top side with the decor forms the carrier layer, and the dried and cured synthetic resin with which the paper has been impregnated constitutes the surface of the synthetic resin. Alternatively, for example, the decorative surface may also include an additional protective layer in the form of a transparent coating placed on the top side of the decorative paper, which is also impregnated with synthetic resin and pressed and cured together with the decorative paper. Additional layers may also be placed, such as layers on the underside of the carrier layer to stabilize the carrier layer, such as layers of kraft paper, or a layer of material, such as a panel, for example.

Ready-to-use decorative surfaces in the sense of the invention are known, for example, as laminate (HPL), high pressure laminate (CPL), direct pressure laminate (DPL), and others, which are formed either as laminates for bonding material, in particular, panels, or already connected to the material. In this case, the surface of the synthetic resin was transformed by heat and pressure into its ready-to-use state, in which the synthetic resin is, for example, in the form of a thermosetting plastic.

The decorative surface in the sense of the invention can also be formed as a lacquer surface. In this case, the decor can be printed or lacquered on the carrier layer. On top of the decor, an additional, for example, transparent varnish layer can be applied, which is made as a protective layer. Paper layers, films of synthetic material or also materials, in particular panels, such as boards of wood-based material, can also be used here as the carrier layer. Thus, it is possible, for example, that the decorative surface is in the form of a wood-based board provided with a decor by a direct padding process. So-called facing films can also be used, which have a decor printed on the top side and, if necessary, a protective layer placed on them, as ready-to-use, fully cured decorative surfaces. For example, facing films can be glued onto the panel.

By material may be meant a carrier material which can be bonded to the carrier layer. The material used is particularly preferably wood-polymer composite (WPC) or wood-based material, in particular fibrous material, compact density fibreboard (CDF), medium density fibreboard (MDF), high density fibreboard (HDF), oriented strand board (OSB), fiber cement board, or gypsum board. WPC is also understood to mean corresponding variants with paper, bamboo or also stone material as filler. The material is preferably a board-like material, in particular a WPC board or a wood-based material board. They can be advantageously used, for example, for wall coverings, ceiling linings or floor coverings. In particular, in the field of interior design, wood-based boards, such as CDFs, MDFs, HDFs, chipboards or OSBs, are used for wall coverings, ceiling claddings or floorings.

The decorative surface, whether it is a synthetic resin surface or a lacquer surface, is fully cured and etched in the ready-to-use state both before the application of the mordant coating material and before the color change (etching) is carried out, i.e. , the decorative surface must be immediately etched after the coating material has been applied. In addition, the decorative surface, as already mentioned, can have a suitable surface structure, for example an embossed or lacquered structure.

The coating material is connected, firstly, with a decorative surface ready for use, and secondly, the coating material is designed in such a way that the stain is particularly easily connected to the coating material and can therefore penetrate into the layer of the coating material. In order to improve the connection between the decorative surface and the covering material, the decorative surface is particularly preferably subjected to a pre-treatment. By means of pre-treatment, an improvement in the bonding capacity between the coating material layer and the decorative surface is achieved.

According to one improvement of the invention, an adhesion promoter is applied to the decorative surface for pre-treatment, the adhesion promoter being applied as a separate layer prior to application of the coating material layer, and gelation, drying or complete curing is allowed. The promoter forms a good and strong bond directly to the decorative surface and furthermore has the property that a particularly stable bond can also be formed with a subsequent layer of coating material deposited on the adhesion promoter. The application of the adhesion promoter can be carried out according to the application of the coating material layer, for example by spraying, knurling, scraper or the like.

Alternatively or additionally, the adhesion promoter is particularly preferably applied to the decorative surface together with the coating material as a coating material mixture. In this case, the adhesion promoter is mixed into the coating material. Thus, for example, in the case of decorative surfaces that are formed as a synthetic resin surface, a particularly good bonding of the coating material is achieved by first applying a separate layer of adhesion promoter to the decorative surface, and then applying the coating material mixed with the adhesion promoter. Often, however, just in the case of the formation of lacquer surfaces as decorative surfaces, the admixture of an adhesion promoter to the coating material is sufficient. Alternatively, the coating material layer itself may also contain additives/components which give it adhesion promoter properties.

According to one further embodiment of the invention, the adhesion promoter comprises a UV curable acrylate lacquer or a UV curable polyurethane lacquer (PU lacquer). This applies both to the adhesion promoter applied as a separate layer and to the adhesion promoter mixed into the coating material. Both the UV-curable acrylate varnish and the UV-curable polyurethane varnish can be applied particularly flexibly and form a particularly secure bond to a wide variety of decorative surfaces.

Particularly preferably, the decorative surface is pre-treated by corona treatment, grinding, acid or alkali etching, powder coating treatment, plasma treatment, flame treatment and/or fluorination. However, the above pretreatment steps can be carried out alternatively or in addition to the pretreatment with the adhesion promoter described above.

In addition, the coating material may include a mordant and be formed as a mordant-equipped liquid synthetic resin that is applied to a surface and compressed therewith in a press.

However, according to one further embodiment of the invention, it is provided that a lacquer provided with a mordant additive (according to the above definition) is applied as a coating material. The lacquer-based coating material can be processed in a particularly simple way and, in particular, the drying and curing carried out after application can be carried out without detrimental effect on the decorative surface placed under the layer of coating material.

According to one additional embodiment of the invention, kaolin, chalk, alumina, silica, mica, quartz sand, silicate, glass beads, glass powder, silane, cellulose or natural fibers are used as a mordant. For example, kaolin can be used in the form of hydrated aluminum silicate. The mordants may preferably be silanized. Particularly preferably, the kaolin is used in hydrogenated and/or calcined form, a mixture of both forms being preferred, for example in a ratio of 50 wt.%:50 wt.%. Thus, the calcined form makes it possible to ensure particularly good fixation of the etching paints, while the hydrated form is transparent and thus prevents a reduced opening of the decor. Preferred mordants can be used both in the lacquer-formed coating material and in the resin-formed coating material.

In addition, silanized kaolin is preferably used, since it further improves the adhesion of the stain paint. It can be used as a mixture with non-silanized kaolin. In this case, the proportion of silanized kaolin is particularly preferably between 50 wt.% and 80 wt.% of the total consumption of kaolin.

In addition, kaolin and chalk, when applied as liquid stain pigments, create a suction effect, due to which the pigments are particularly easy to penetrate into the layer of the coating material, and, accordingly, ensure particularly good binding of the pigment particles from the stain on the layer of the coating material (chemical). In addition, in the case of kaolin and chalk, a particularly good fixation of the pigment in/on the coating material is achieved.

In order to further improve the incorporation of the pigment into the coating material layer and, accordingly, the binding of the stain on the coating material layer, and thus also in a particularly simple way to create a surface coloration, according to a further embodiment of the invention, the weight fraction of the mordant on the coating material before coating is from 10 wt. .% to 60 wt.%, preferably from 10 wt.% to 50 wt.%, particularly preferably from 20 wt.% to 50 wt.%, preferably from 30 wt.% to 50 wt.%. The preferred weight ratios, with the coating still being applied, ensure a particularly good and uniform formation of an open-pore surface, so that the incorporation of color pigments into the synthetic resin/lacquer surface can be carried out particularly evenly and efficiently and, accordingly, they can be fixed in this surface.

By mordant is meant a filler which is present in the coating material and ensures the formation of a porous surface (open-celled) of the applied and dried and, accordingly, cured layer of the coating material. In addition, the mordant can improve the bonding ability of the coating material on the surface-formed synthetic resin or lacquer surface of the decorative surface, and thus the bonding ability of the mordant on the coating material.

By open porosity is meant that the cured layer of the coating material is formed to absorb dyes (color pigments) into the layer. This can be achieved by means of a dressing additive. In this case, the cured coating can be in a translucent to completely transparent state, so that the decor printed on the carrier layer can be perceived practically without distortion. It may be that the cured coating already introduces the first basic color tone by means of a decor, which is later changed again by applying a pigment.

According to a further embodiment of the invention, the coating material comprises an aminoplast-based varnish, in particular a urea resin such as urea-formaldehyde resin (UF), melamine-urea-formaldehyde resin (MUF), acrylate, polyester, polyurethane rubber (PUR) , nitrocellulose, and/or phenolic resin, or a mixture of at least two of the above substances. In this connection, acrylate resins have proven to be particularly suitable for forming the layer of coating material without a mordant, and they can also be used with a mordant. Also, for example, a varnish based on acrylic, alkyd resin and/or latex can be used. In particular, varnishes can be formed as dispersions. For example, it is also possible to use as a coating material an adhesion promoter, for example based on a UV varnish with a mordant additive.

The use of a mixture of lacquer and kaolin is preferred as a coating material with a mordant additive to obtain a lacquer surface. In this case, in particular, a varnish based on acrylate or polyurethane (PUR) with a stain based on kaolin is used, since this combination also makes it possible to distribute the stain in the coating material particularly evenly and to bind the subsequently applied stain into the layer particularly well, or , respectively, on a layer of coating material. In addition, UV acrylate varnishes and/or UV polyurethane varnishes which are particularly suitable as adhesion promoters can also be combined particularly favorably with corresponding coating materials which are based on acrylate or polyurethane. Preferably, both the lacquer of the coating material and the adhesion promoter are based on the same group of substances.

According to a further embodiment of the invention, the application of the coating material to the upper side of the carrier layer, ie the decorative surface ready for use, is carried out with a coating roller, a squeegee or a spray device. In this way, the thickness of the thin layer is adjusted in a particularly simple way, so that practically unchanged good technical properties of the decorative surface are obtained. The application is carried out, for example, with a rubber roller, in particular a sponge rubber roller, which has a hardness of 30-40 Shore A (typically 60-80 Shore A).

The coating material is particularly preferably water-based, that is to say it is applied as an aqueous solution. According to a further embodiment of the invention, after application, in the first stage, drying of the coating material is carried out, during which the solvent, in particular water, is volatilized. Drying can be carried out, for example, by applying heat, in particular in the temperature range of 40° C.+/-5° C., and by means of circulating air. The layer of coating material is then at least partially cured, i.e. gelled, but alternatively a complete curing can also be carried out. Curing is preferably carried out by means of UV radiation and increases the resistance of the coating material layer to mechanical or chemical attack. For UV curing, a gallium lamp may preferably be used, for example with a power of 80 watts.

The color-changing post-treatment is carried out after complete drying (eg by heat and circulating air) and curing (eg by UV radiation) of the coating layer and can be carried out with conventional wood stains, in particular conventional water-based stains. , oil-based stain or solvent-based stain for wood surfaces. In this case, the basic color of the decorative surface specified by the decor is individually changed additionally, i.e. after the initial industrial production of the synthetic resin surface/lacquer surface. For particularly good bonding on the layer of coating material, the mordant also contains a small amount of binder (polymer).

A color-changing decorative surface is much more economical and resistant to external influences compared to stained solid wood surfaces.

Regardless of its execution as a synthetic resin surface or a lacquer surface, and also regardless of the type of material used for the layer of coating material and, accordingly, regardless of the mordant used if necessary, after applying and, if necessary, drying the mordant, an additional mordant is applied to the surface. , in particular, a thin protective layer to protect against external influences also the pigment particles from the mordant. For the protective layer (fixing layer), for example, a lacquer can be used, in particular according to the materials mentioned above for the coating material layer. For example, it can also be that the protective layer is applied in the form of an oil or wax, this variant being applicable in particular to floor panels.

In addition, the problem is solved by means of a material with a ready-to-use, fully cured decorative surface, by means of a layer of coating material applied to the upper side of the decorative surface, which is formed to absorb and bind pigment particles.

In this case, the pigment particles are usually introduced by means of a colored stain, that is, for example, an aqueous stain, an oil-based stain or a solvent-based stain. In this case, the panel according to the invention allows, in addition to industrial processing, also processing by the material processing worker or the end user, i.e. also non-industrial influence on the color design of synthetic resin surfaces.

The material includes, for example, a carrier layer on which the decor is printed and which has one or more layers of paper, such as decorative paper and/or kraft paper. The material can also be understood as a carrier material on which a decor has been directly printed. In particular, the material may be formed as a board material. The panel may consist of a different material, such as wood board. Particularly suitable are particle boards, fiber boards such as MDF, HDF or CDF boards, OSB boards, cement fiber boards, gypsum boards or WPC boards, which are particularly suitable for forming board materials.

It should be noted that by means of the applied layer of coating material, an additional, permanent coloration of the ready-to-use, fully cured decorative surface is ensured, namely, regardless of its execution as a synthetic resin surface or a lacquer surface. The ready-to-use, fully cured decorative surface does not contain any mordant prior to the application of the top coat.

An additional possibility of using for a layer of mordant coating material is, for example, that in the case of furniture decors, but also wall, ceiling or floor cladding panels with a homogeneous, porous Synchronpore surface, and regardless of whether a lacquer surface or a surface is formed synthetic resin, provide a visual increase in pores. The pores are most often formed as depressions. That is, after application of the coating material, more coating material is collected in the area of the recesses, which can also receive/bind more pigment particles from the stain, so that the color appearance of the pores changes more compared to other areas of the decorative surface. In addition, this can be enhanced or, alternatively, created by the fact that the coating material is partially washed again immediately after application, namely in such a way that the coating material with the mordant additive mainly remains present only in the region of the pores (recesses).

Although some aspects have been described in connection with the method, it is understood that these aspects also represent a description of the corresponding device, so that the corresponding step of the method should be understood as a unit or structural element of the device. Likewise, the aspects that have been described in connection with a device block or structural element also represent a description of the corresponding method step.

In the following, the invention is described in more detail by way of exemplary embodiments.

As shown:

Fig. 1 schematically represents a color-changing decorative surface obtained by the process according to the invention;

Example 1 describes the production of a color-matched direct-printed decorative surface.

Example 2 describes a first method for producing a color-variable decorative surface using a roller coater;

Example 3 describes a second method for producing a color-variable decorative surface using a roller coater;

Example 4 describes a process for producing a color-changing decorative surface using a spray device;

Example 5 describes an additional method for obtaining a color-variable decorative surface;

Example 6 describes an additional method for obtaining a color-variable decorative surface.

Figure 1 shows a side view of a carrier layer 1 with a decorative surface 2 ready for use. The carrier layer 1 here is designed as a decorative paper 3 impregnated with synthetic resin with a decorative print. Placed on top of the decorative paper is an outer cover 4 which forms part of the decorative surface 2. The décor here shows the grain of the wood, but alternatively it can also show, for example, ceramic tile decor, stone decor or fancy decor. The outer cover 4 comprises a synthetic resin-impregnated cover paper which, when cured, is completely transparent so that the decor is practically visible.

Under the carrier layer 1, a panel 8 is formed. The panel 8 consists of a wood material, here particle board. Alternatively, boards of other materials or other wood based panels such as MDF boards, HDF boards and the like can also be used. The carrier layer is firmly glued to the panel.

In addition, additional intermediate layers can be placed between the panel 8 and the decorative paper 3. For example, an additional paper layer (not shown here), such as kraft paper, may be placed instead of the wood material panel.

Like the cover layer 4, the decorative paper 3 has also been impregnated with synthetic resin. Here, melamine was used in both layers. The synthetic resin surface 2 was in a short cycle press (not shown here) bonded to the panel under pressure and heat and fully cured. In this case, a structural decor (not shown here) was embossed into the surface of the cover layer 4.

In order to subsequently change the color of the synthetic resin surface 2, that is, to make it suitable for etching, the synthetic resin surface was subjected to a pretreatment. To do this, a liquid adhesion promoter 5 was applied here on the structured surface 2 of the synthetic resin. This was done with a spray device (not shown here), alternatively, for example with a roller coater. The adhesion promoter 5 was then gelled.

Thereafter, a layer 6 of a coating material was applied to the adhesion promoter 5 . The top coat is formulated as an acrylate-based UV-curable lacquer. In this case, it contains a dressing agent 7, which, however, is optional. It was applied to the adhesion promoter 5 using a roller coater (not shown here). After application of layer 6, this and also the adhesion promoter 5 based on the UV-curable varnish were completely cured.

Alternatively or additionally, it is also possible to apply the adhesion promoter 5 to the decorative surface 2 together with the coating material as a mixture. Also alternatively or additionally, "mechanical" pre-treatment of the decorative surface 2 could be performed. For example, this could be done by corona treatment, fluoridation, grinding, etching, or plasma or flame treatment. Of course, the application of the coating material would also be possible without an adhesion promoter and thus without pre-treatment.

In addition to increasing the bonding strength with the decorative surface and thus the mordant on the coating material, the mordant 7 present forms the layer 6 as a porous surface (not shown here), i.e., the mordant 7 is very evenly distributed in the layer 6. As a mordant 7 here, kaolin (not shown here) is mixed into the coating material. In this case, the ratio by weight between the liquid coating material and kaolin before application was 1:1.

For subsequent changes in the color of the surface 2 of the synthetic resin, the layer 6 was mordanted, for example, based on a water-based solvent or oil-based. The pigments in the mordant were chemically absorbed by the coating material layer and accordingly bonded to it. In addition, the pigment particles from the mordant penetrated into the coating material layer due to porosity. The solvent evaporated. As a result, the overall color impression of the synthetic resin surface 2 was changed. A fixing layer could then be applied.

In the above example, alternatively, a ready-to-use lacquer surface can also be used instead of a synthetic resin surface. For example, it may include embossed pores in the lacquer that represent structural decoration.

Example 1

In a further exemplary embodiment, a direct-printed decorative surface was obtained. The decorative surface is fully cured and ready for use. In order to obtain a decorative surface, the wood-based material board, here MDF board, has been pre-treated by sanding and applying a direct print primer. The primer layer(s) were directly applied with colored decor, in this case by means of an engraved roller. Alternatively, the colored decor could be digitally printed. Then the colored decor was covered with a protective layer, which consists of several thin layers of colorless varnish. The clear lacquer was based on a UV-cured acrylate lacquer.

In addition, surface structuring was carried out over the protective layer. All decorative surface layers were fully cured. In this case, this was done by means of UV radiation.

The decorative surface thus obtained, ready for use, was then coated with a coating material. The application was carried out using a rolling roller. Here, the coating material also includes an optional mordant, so that the coating material, for example, is a mixture of lacquer and kaolin, which was obtained in a mixture ratio of 1:1. For particularly good adhesion of the coating material to the decorative surface, it is optionally possible to pre-treat the decorative surface with a corona discharge. A UV curable acrylate lacquer was used as the lacquer in the coating material. The pretreated decorative surface was then coated using a sprayer, alternatively a roller coater, dried and then fully cured using UV light. Now the wood material panel with the decorative surface directly printed and the overlay material layer placed on the surface can be etched. That is, a mordant containing pigment particles can be applied to the surface, both commercially and by the end user. For example, this can be done with a roller, brush, roller, or also with a cloth. In this case, the pigment particles bind to the coating material and, accordingly, penetrate into the porous surface of the coating material formed by kaolin and are fixed there. After removal of the excess stain and drying of the stain, a discoloration of the decorative surface is achieved while the decor remains substantially visible. In order to protect the etched coating material layer, an additional protective layer (fixation layer), for example a lacquer layer, can then be applied in addition.

An additional initial product for obtaining a subsequently modified decorative surface can be, for example, facing films. For example, they have a carrier layer of paper or synthetic material. A decor is printed on this carrier layer and a protective layer is placed over the decor. Decor and protective layer are completely dried and cured accordingly.

As a rule, the facing film is glued/pasted onto a material, such as a wood-based material board, using a laminating device and, for example, using a hot melt adhesive. The decorative surface of the facing film can also be pre-treated according to the example described above before or after gluing, so that a layer of dressing material with a dressing additive is then applied, dried and, accordingly, completely cured, so that the facing film has a subsequently color-changing decorative surface.

Example 2

Starting from a ready-to-use decorative surface with a colored decor and a structural decor based on lacquer or synthetic resin, using a roller coater, the cover material is rolled onto the ready-to-use decorative surface. The cover material is formed as an aqueous solution. In particular, the cover material forms at least a practically transparent layer, so that the colored decor remains visible even through the cover material layer. As coating material, for example, Hydro Spezialbeize FT from Hesse or Hydro UV Beize FT also from Hesse can be used. When applied to a decorative surface, the material is rolled in an amount between about 8 g/m ² and 14 g/m ² . The coating material layer is then dried, during which the water evaporates. Drying is carried out at a temperature of about 40° C. and for about 20 seconds. Drying can be carried out, for example, by drying in circulating air.

In particular, in order to increase the strength, eg scratch resistance, of the coating material layer, the dried coating material layer is at least partially cured by UV radiation, i.e. subjected to at least pre-crosslinking (gelling). As a result, the carrier layers with the decorative surfaces and the cover material layer can be layered on top of each other without problems and can be transported without sticking together. At least partial curing is in particular carried out using a gallium-based UV lamp.

The knurling is carried out by means of a rubber roller, in particular a sponge rubber roller. The rubber roller has, for example, a hardness Shore A between 30 and 40.

Example 3

Compared to the preparation of the ready-to-use decorative surface of example 2, the production method of example 3 differs only in the covering material used. In this second embodiment of the method, the UV-Grund agent from Hesse, in particular UG 7541-FT, is used as the coating material. It is applied in an amount between 10 g/m ² and 15 g/m ² .

Example 4

Here, too, starting from a ready-to-use decorative surface with a colored decor and a structural decor based on lacquer or synthetic resin, a coating material is applied. The application is carried out using a spray device. As covering material, for example, Hydro Spezialbeize or Lösemittelbeize FT from Hesse is used. The cover material is applied in an amount between 15 g/m ² and 30 g/m ² . Drying is then carried out for about 3 minutes to 4 minutes. Drying can be carried out by drying in circulating air. It is preferably performed at temperatures from 30°C to 40°C.

Then the coating material according to examples 2 and 3 using UV radiation is subjected to at least partial crosslinking (gelling) or completely cured.

The decorative surfaces of Examples 2-4 are prepared for the application of the stain after curing or, respectively, partial curing (gelling, partial cross-linking). Suitable stains are all commercially available colored stains, for example those provided for wood or wood-containing materials. Thus, for example, aqueous mordants, oil mordants or mordants with other solvents can be used. In addition, colored mordants are preferably used which contain at least a small amount of binder (polymer) in order to improve bonding on the coating material layer.

After application and drying, if necessary curing of the mordant and the associated discoloration of the decorative surface, a fixing layer can be applied, which also acts as a protective layer. The fixing layer prevents the mordant layer from separating from the layer of coating material when exposed (mechanically, chemically).

The application of the fixing layer can also be carried out by roller application or by using a spray device. In a particularly preferred embodiment of roller application, which in particular can be carried out commercially, a layer of Hesse UV Überzugslack, for example UU 7333, is first applied in an amount of from about 3 g/m ² to 5 g/m ² , and by means of UV radiation, gelation is provided, for example, using a mercury-based UV lamp with a power of 80 W. Then, a second layer of the same top coat is applied in the same amount of applied material. Both layers are then cured using the UV lamp mentioned above, whereby 2-3 curing cycles can also be carried out, for example.

The following lacquers from Hesse are suitable for applying the fixing layer with a spraying device:

1. UV Überzugslack, eg UU 7333 with an application amount of 3 g/m ² to 5 g/m ² , in two coats according to the roller application described above;

2. Hydro UV Einschichtlack HUE 8656 with application amount from 100 g/ ^m2 to 120 g/ ^m2 ,

3. Hydro Topsiegel HE 65 09 single-layer application and application amount from 100 g/m ² to 120 g/m ² ,

4. PUR Schichtlack DE 4503 with an application amount of 100 g/m ² to 120 g/m ² .

The lacquers are dried and/or cured in accordance with the regulations for them, and, accordingly, in the case of multi-layer application between the individual application cycles, for example, gelation is provided.

An alternative color change can be carried out, for example, by means of a layer of lacquer instead of etching. In this case, a layer of lacquer, in particular a colored lacquer, is applied to the at least partially cured layer of the coating material and dried and/or cured, for example with UV radiation.

The layer of coating material, both during the application of a stain and during the application of a lacquer, among other things, acts as an adhesion promoter. Therefore, the cover material is formed in order to adhere to a ready-to-use decorative surface made of synthetic resin or lacquer and, accordingly, to create a connection with the decorative surface. Secondly, the layer of coating material allows the mordant and, accordingly, the applied varnish to adhere to it, and, accordingly, the possibility of creating a connection with its surface.

Example 5

In the alternative of applying a stain to the application of varnish on the layer of coating material, it also prevents the varnish from tarnishing, so that with a structured surface, a structured painted surface can be obtained even with small amounts of colored varnish. The application of lacquer to the layer of coating material is therefore particularly suitable in order to obtain, for example, surfaces such as white ash effect and others, in which the porous surface structure remains present to the greatest extent, however, in color according to the color varnish. The surfaces obtained in this way are very similar to the surfaces of natural wood with porous structures varnished with colored lacquer, and visually and to the touch are superior to the surfaces obtained using the film. The lacquering of the cover material layer can be used in particular for interior surfaces such as, for example, door surfaces.

Example 6

An additional embodiment for obtaining a color-variable decorative surface is represented by applying at least one layer of coating material to a ready-to-use decorative layer of lacquer or synthetic resin. When using a coating material without a mordant additive, for example, an acrylate resin-based lacquer used as a primer, for example Hydro-UV Schichtlack HUE 8656x coating material from Hesse-Lignal, can be used.

The cover material is applied in an amount between 10 g/m ² and 30 g/m ² . In particular, application is carried out using a rubber roller coating roller. The rubber roller preferably has a Shore A hardness of 40 (hardness 40 Shore A).

The coating material layer is then dried and cured, preferably at temperatures between 60°C and 180°C. The drying time is between 10-20 seconds.

The above coating material without mordant, after drying and curing, also forms a ready-to-use, suitable for etching surface, which has sufficient porosity so that subsequently applied pigment particles can be deposited in and on the outer layer of the coating material. The curing is carried out in this case, in particular, by means of UV radiation, for example, using a mercury UV lamp with a power of 100-400 MJ/m ² . For particularly uniform curing, 5 mercury UV lamps with a power of 120 W each are preferably used.

To further change the color of this decorative surface, for example commercially available stains based on water or other solvents can be used. For example, "Parquet-Colour" from Hesse-Lignal can be used. The etched and dried surface can also be resealed with a suitable protective layer later. For this, a surface varnish based on a two-component PUR lacquer made of acrylate resin is offered. For example, a PUR SUN-CAPE DE 4800x covering material from Hesse-Lignal can be used.

When applying a layer of coating material to a decorative surface which is subsequently bonded to the material, such as when applied to a surface layer (HPL, CPL, etc.), an etchable decorative surface can be adhered to the material. This is preferably done with PUR hotmelt at 130° C.+/-10° in a calender with a line pressure between 50 N/m and 80 N/m. The preferred parameters ensure that the glued decorative surface is practically suitable for etching even after laminating.

Claims (21)

1. A method for producing a color-changing decorative surface (2), including the steps: - forming a ready-to-use, fully cured, synthetic resin-containing decorative surface (2) on the carrier layer (1), wherein the complete curing of the synthetic resin is carried out under the influence of heat and additionally applied pressure, - applying at least one layer (6) of a transparent lacquer on the cured decorative surface (2), which allows the absorption of pigment particles that are applied by means of a colored mordant, - drying and curing the layer (6) of the coating material. 2. Method according to claim 1, characterized in that the decorative surface (2) ready for use is pre-treated before applying at least one layer of clear lacquer. 3. The method according to claim 2, characterized in that for pre-treatment, an adhesion promoter is applied to the decorative surface (2), wherein the adhesion promoter is applied as a separate layer before applying the clear varnish layer (6) and gelled, dried or fully cured. 4. Method according to claim 3, characterized in that the adhesion promoter is applied to the decorative surface (2) together with the clear lacquer in the form of a coating material mixture. 5. The method according to claim 3, characterized in that the adhesion promoter comprises a UV curable acrylate varnish or a UV curable polyurethane varnish (PU varnish). 6. Method according to claim 1, characterized in that, for alternative or additional pre-treatment, the decorative surface (2) is subjected to corona treatment, grinding, acid or alkali etching, powder coating, plasma treatment, flame treatment and/or fluorination. 7. The method according to p. 1, characterized in that a mixture is applied as a transparent varnish, including a varnish and a stain additive (7). 8. The method according to claim 7, characterized in that kaolin, chalk, alumina, silica, mica, quartz sand, silicate, silanized materials, glass beads, glass powder, cellulose or natural fibers are used as a mordant additive (7). 9. Method according to claim 7, characterized in that kaolin in hydrogenated and/or calcined form is used as a dressing agent (7). 10. Method according to claim 7, characterized in that the weight content of the mordant (7) in the clearcoat is between 10% by weight and 60% by weight. 11. Method according to claim 7, characterized in that the weight content of the mordant (7) in the clearcoat is between 20% and 50% by weight. 12. Method according to claim 7, characterized in that the weight content of the mordant (7) in the clearcoat is between 30% and 50% by weight. 13. The method according to claim 1, characterized in that a clear lacquer is used, which includes a lacquer based on amino plastics, in particular a urea resin such as urea-formaldehyde resin (UF) or melamine-urea-formaldehyde resin (MUF), acrylate, polyester, polyurethane rubber (PUR), phenolic resin, nitrocellulose or based on a mixture of at least two of the above varnishes. 14. The method according to p. 1, characterized in that a water-based transparent varnish is used. 15. Method according to claim 1, characterized in that the clear lacquer is dried, in particular by circulating air drying. 16. Method according to claim 1, characterized in that the clear lacquer is at least partially cured after drying, in particular using UV radiation, in particular fully cured. 17. Method according to claim 1, characterized in that the application of the clear lacquer is carried out on the upper side of the carrier layer (1) with a roller, squeegee or spray device. 18. A composite material with a ready-to-use, fully cured decorative surface (2), having a layer of transparent varnish with mordant additives (7) applied on the upper side of the decorative surface (2), which forms a porous surface and is formed to receive and bind pigment particles.

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