BE1028813B1 - PROCEDURE FOR FINISHING A SUBSTRATE WITH A HIGH GLOSS AND SUBSTRATE OBTAINED BY THIS - Google Patents

Abstract

The present invention relates to a method for obtaining a high gloss finish on a substrate, the substrate as well as a kitchen construction such as a kitchen cabinet or countertop comprising the substrate.

Description

PROCEDURE FOR FINISHING A HIGH GLOSS SUBSTRATE AND SUBSTRATE OBTAINED BY THIS

TECHNICAL FIELD The present invention relates to a method for obtaining a high gloss finish on a substrate, the substrate as well as a kitchen construction such as a kitchen cabinet or countertop comprising the substrate.

BACKGROUND ART Finishing wooden substrates or wooden composite substrates with a high gloss coating is known in the art.

For rapid processing of the substrates, a coating is preferably used which can be cured and/or polymerized by means of a UV treatment. However, curing or polymerization of such photoinitiable coating compositions is difficult to control. Photo-initiable coatings are therefore applied in a dark environment. However, a dark environment has the disadvantage that a spray bell for applying the coating is difficult to control.

High gloss lines known in the art meet this by blindly applying an excess coating on and around a substrate. However, such a method is very inefficient and wasteful.

There is a need in the current state of the art for a system that allows the application of a high gloss varnish coating with minimal wastage.

The present invention aims to find a solution to at least some of the above-mentioned problems.

SUMMARY OF THE INVENTION In a first aspect, the invention relates to a method for obtaining a high gloss finish on a substrate according to claim 1.

In a second aspect, the invention relates to a substrate with a high gloss finish.

In a third aspect, the invention relates to a kitchen construction such as a cupboard or top. The kitchen construction comprising a substrate made according to the first aspect and/or a substrate according to the second aspect.

Preferred embodiments of the present invention are discussed in claims 2 to 17, as well as throughout the specification. The present invention is advantageous by determining one or more coordinates of this substrate plane before applying a varnish coating to a substrate plane. These coordinates can then be used to control a spray clock in a dark room by means of, for example, a computer-controlled robot arm. This allows the varnish coating to be applied exactly, i.e. without excess around the substrate surface. The present invention therefore has the particular advantage that less varnish is wasted and a more precise finish is possible. In addition, the present invention is also advantageous due to a varnish composition that can be cured by means of a UV treatment, as well as has an acceptable curing speed at ambient temperature. As a result, high gloss substrates can be produced quickly and efficiently. Further advantages, embodiments and preferred embodiments of the invention are discussed below in the detailed description, examples and figures.

DESCRIPTION OF THE FIGURES Figure 1 shows a dark room with a spray bell for applying varnish to a substrate surface according to the present invention.

Figure 2 shows a room for treating an applied varnish layer according to the present invention with UV light.

DETAILED DESCRIPTION The invention relates to a method for obtaining a high gloss finish on a substrate, the obtained substrate as well as a kitchen construction such as a kitchen cabinet or countertop comprising the substrate. In what follows, the invention is described in detail and preferred embodiments are explained.

Unless otherwise defined, all terms used in the description of the invention, including technical and scientific terms, have the meaning as generally understood by those skilled in the art of the invention.

For a better assessment of the description of the invention, the following terms are explicitly explained. “A”, “the” and “the” in this document refer to both the singular and the plural unless the context clearly dictates otherwise. For example, “a segment” means one or more than one segment.

When "about" or "around" in this document is used with a measurable quantity, a parameter, a duration or moment, etc., variations of +/-20% or less, preferably +/-10% or less, more preferably +/- 5% or less, even more preferably +/-1% or less, and even more preferably +/-0.1% or less than and of the quoted value, to the extent that such variations of are applicable in the described invention. However, this should be understood to mean that the value of the quantity using the term “approximately” or “around” is itself specifically disclosed.

The terms “comprise”, “comprising”, “consist of”, “consisting of”, “include”, “contain”, “containing”, “include”, “include”, “contain”, “include” are synonyms and are inclusive or open terms designating the presence of the following, and which do not exclude or preclude the presence of other components, features, elements, steps known from or described in the art. Citing numerical intervals through the endpoints includes all integers, fractions and/or real numbers between the endpoints, including these endpoints.

In a first aspect, the invention relates to a method for obtaining a high-gloss finish on a substrate suitable for use in the manufacture of a cabinet or top, the method comprising the steps of: - providing a substrate substantially manufactured from a wooden material and/or a wood composite material; - preparing a varnish from a varnish kit comprising o a photoinitiator; and o a polymerization component comprising a curable or polymerizable organic material;

wherein the preparation of the varnish is by mixing the components of the varnish kit; - determining one or more coordinates of the substrate plane in the substantially dark space from a camera image of the substrate plane, the coordinates of the substrate plane being used to drive a spray clock configured to apply the varnish layer in the in essentially dark space; - applying a varnish layer on a substrate surface with the prepared varnish, wherein the application of the varnish layer takes place in a substantially dark room; and - exposing the applied varnish layer to a UV treatment for curing or polymerizing the organic material. In a second aspect, the invention relates to a substrate with a high gloss finish obtained according to the first aspect of the present invention. In a third aspect, the invention relates to a kitchen construction such as a cabinet or top or a combination thereof, comprising a substrate made according to the first aspect of the present invention and/or the second aspect of the present invention.

A person of ordinary skill in the art will appreciate that the method according to the first aspect of the invention can be used to prepare a substrate according to the second aspect of the invention. Moreover, it is apparent to a person of ordinary skill in the art that a substrate according to the first and/or second aspect can be used in a kitchen construction such as a cabinet. In what follows, the three aspects of the present invention are therefore discussed together. In addition, any feature described either above or below may refer to any of the three aspects, even when the feature is described in conjunction with a particular aspect of the present invention.

The present invention relates to a method for obtaining a high gloss finish on a substrate face of a substrate. The substrate according to the invention is an object suitable for manufacturing a cabinet or top. In particular, the substrate refers to a panel, sheet, batten, beam, frame member, sash, etc. The substrate is mainly made of wood and/or wood composite material. In particular, the material of the substrate is laminate (sheet), solid wood, veneer, wood composite, fiberboard (Eng. fibreboard; in particular MDF) and/or chipboard. More specifically, the substrate refers to an MDF panel or a veneer sheet.

A "laminate sheet" as used herein refers to a sheet or web made substantially from a laminate material, wherein the laminate material comprises a core layer sandwiched between an outer and inner layer and wherein the outer, inner and core layers are preferably bonded by mixing these layers with a resin and/or glue and by subsequently pressing the layers together at high pressure and/or temperature. The core layer of the laminate material may also comprise one or more layers. The different layers of the laminate are preferably paper-like layers. In particular, laminate sheet refers to an HPL (Eng. High Pressured Laminate), DPL (Eng. Direct Pressed Laminate), CPL (Eng. Continuous Pressed Laminate), etc. For rapid processing of the substrate according to the invention, a varnish that is curable or polymerizable by means of an ultraviolet (UV) treatment. Radiation sources that can be used for the UV treatment are, for example, high and medium pressure mercury lamps. To avoid any risk when dealing with very short wavelength UV light, i.e. UV-B and/or UV-C light, preference is given to fluorescent lamps that produce the less harmful UV-A light. To enable curing and/or polymerization, the varnish comprises a photoinitiator and a polymerization component. "Photoinitiator", as used herein, refers to a term known in the art that denotes a compound that forms a reactive species, such as a radical, cation or anion, when exposed to light of a particular wavelength. In particular, the light should have a wavelength in the ultraviolet (UV) and/or visible region of the electromagnetic spectrum. "Polymerization component", as used herein, refers to a term known in the art that denotes a monomeric, oligomeric and/or polymeric organic material that is curable or polymerizable. In particular, the organic material is a photopolymer. Due to the limited lifespan of such varnish, it is prepared from a varnish kit that contains the various components separately.

For controlled and uniform curing or polymerization of a varnish layer, it is preferably applied in a substantially dark room. Thus, the applied varnish layer can spread evenly before it hardens. If the varnish is applied in a space that is not, or only partially, darkened, the varnish may not adhere sufficiently to the substrate surface. This poor adhesion is, for example, characterized by a too low degree of coverage of the varnish layer, breaks, cracks, flakes, etc. In the case of applying the varnish by means of a spray gun, the varnish may already partially harden or polymerize before it is removed from the surface. the clock reaches the substrate plane.

In addition, uncontrolled curing or polymerization of the varnish can clog a nozzle of the bell.

The term "dark space" refers to a space that is free from electromagnetic radiation in the ultraviolet (UV) and/or visible region of the electromagnetic spectrum.

In order to apply the varnish layer in the substantially dark space, in the prior art an excess of varnish is often blindly applied to and around the substrate surface.

To prevent such wastage, one or more coordinates of the substrate plane are preferably determined from a camera image of the substrate plane before applying the varnish.

The camera image is, for example, recorded by a camera module which is mounted inside and/or outside the substantially dark space.

The determined coordinates can then be used to drive a spray bell configured to apply the varnish in the substantially dark space.

However, to perform the above steps, different configurations of both the dark room and the camera module are possible.

According to a preferred embodiment, the camera module is configured to capture the camera image in an illuminated space.

This can be done, for example, by providing a light source in the room and switching it on briefly while recording the camera image.

Preferably, the camera image of the substrate plane is obtained outside the substantially dark space.

As a result, the camera image is captured before the panel is in the dark room.

However, in order to implement this, the position of the substrate plane in the dark space must always be known.

According to an alternative embodiment, the camera module is configured to capture the camera image in the substantially dark space.

This can be done, for example, by using a large aperture, long snooze time, etc.

However, these options require a minimal amount of residual light, which may cause partial curing or polymerization to occur.

Alternatively, the camera module is a thermal camera, i.e. infrared (IR) camera.

However, IR cameras also have the disadvantage that light with a wavelength within the IR spectrum can already partially initiate the curing or polymerization of certain photoactivatable varnishes.

According to a preferred embodiment, the substrate is provided in a fixed position with respect to a reference point both during the acquisition of the camera image and during the application of the varnish layer.

This can be easily implemented by providing the substrate on the same work surface during the acquisition of the camera image as during the application of the varnish layer.

Thus, the location of the substrate plane in the dark space is always known.

This prevents mistakes and waste during the application of the varnish layer.

In addition, the worktop can be mounted on a conveyor belt, elevator module, or combination thereof.

After a curing time of 1 to 3 days, either a dry or wet sanding is possible.

According to a preferred embodiment, after the UV treatment of the varnish layer, the method comprises the step of sanding the varnish layer with an abrasive sheet having a grain of at least P1000, further preferably at least P1200, still further preferably at least P1500 and most preferably at least P3000. Preferably, the sanding comprises eccentrically sanding the varnish layer.

Sanding the varnish layer is necessary to remove all dust particles from the applied varnish layer.

As a result, a sander with excellent dust extraction is preferably used.

According to a preferred embodiment, the method after the UV treatment comprises the step of polishing the varnish layer with a polishing paste applied with a rotary polishing machine.

Preferably, the varnish layer is polished at least 2 hours after sanding.

It is recommended, however, not to polish the varnish layer until 12 hours after sanding.

Preferably, a lambskin is used for polishing.

Preferably, the polishing paste is applied to the lambskin and manually distributed on the substrate surface without turning on the polishing machine.

Preferably, start polishing at the lowest speed of the polishing machine and then slowly increase the speed.

With little pressure, the polisher should be guided over the surface, moving continuously so that the surface does not become too hot.

However, the surface can be cooled with a water spray during polishing.

Depending on an open or closed pore image of the substrate, the substrate face may or may not be pretreated prior to application of the high gloss.

According to a preferred embodiment, the substrate face has open pores.

In the case of open pores, filling the substrate face once or several times is necessary for a quality finish.

If the pores in the substrate face are not filled, blistering may occur after the varnish has cured.

In the case of an open-pored substrate face, the method for applying the varnish layer preferably comprises the step of filling the substrate face.

More preferably, a backfill is applied to the substrate face before filling the substrate face.

Preferably, also after filling the substrate surface and before applying the varnish layer, a filling ground is applied to the substrate surface.

These operations prevent blistering.

Preferably, the method comprises preparing filler for the backfill from a filler kit.

The filler kit comprising a photoinitiator, a reaction compound and a polymerization component with a curable or polymerizable organic material.

The preparation of the filler is done by mixing the components of the filler kit.

When using such photoactivatable filler, the applied backfill should be subjected to a UV treatment for curing or polymerization of the organic material in the applied backfill.

Analogous to the photoactivatable varnish, the backfill is preferably applied in a substantially dark room.

Thus, a controlled and uniform curing or polymerization of the backfill is possible.

In addition, the applied backfill can in this way spread into the pores, crevices, etc. of the substrate surface before it hardens.

If the filling soil is applied in a space that is not, or only partially, darkened, the filling soil may also not adhere sufficiently to the substrate surface.

This poor adhesion is, for example, characterized by a too low coverage of the filling soil, fractures, cracks, flakes, etc.

In the case of the application of the filling soil by means of a spray bell, the filler can already partially harden or polymerize in a light environment before it reaches the substrate surface from the spray bell.

In addition, uncontrolled curing or polymerization of the filler can clog a nozzle of the spray bell.

In the prior art, in order to apply the filling soil in the substantially dark space, an excess of filler is often blindly applied to and around the substrate surface.

In order to prevent such wastage, one or more coordinates of the substrate plane are preferably determined from a camera image of the substrate plane before applying the filling soil.

The camera image is, for example, recorded by a camera module which is mounted inside and/or outside the substantially dark space.

The determined coordinates can then be used to control a spray bell configured to place the backfill in the substantially dark space.

However, to perform the above steps, different configurations of both the dark room and the camera module are possible.

The different configurations of the darkroom and the camera module for the application of the backfill are analogous to those for the application of the varnish.

Preferably, after the UV treatment of the backfill, the method comprises the step of sanding the backfill with an abrasive sheet having a grit of at least P100, further preferably at least P120 and most preferably at least P150. Such rough sanding removes excess backfill from the substrate face. As a result, an even finished substrate surface is obtained. Various open-pored wood or wood composite substrate types are known and are also often referred to as coarse-pore substrates. Examples include substrates made from coarse-pore woods, such as oak or ash. In particular, the substrate is a veneer sheet made of such coarse-pored wood, wherein the substrate surface is a major surface of this veneer sheet.

According to a preferred embodiment, the substrate face has closed pores. Various closed-pore wood or wood composite substrate types are known. Examples include chipboards and bonded fiberboards such as MDF (Eng. Medium-Density Fibreboard) and HDF (Eng. High-Density Fibreboard). In particular, the substrate is a panel made of chipboard or glued fiberboard, the substrate face being a major surface of this panel. Preferably, a primer film is also provided on the closed pore substrate face. According to a preferred embodiment, the organic material of the varnish kit and/or filler kit comprises a polyisocyanate and the varnish kit and/or the filler kit further comprise a reaction compound having an isocyanate reactive group. Such two component systems for preparing a varnish and filler coating are known in the art. The polyisocyanate may comprise a single polyisocyanate or multiple polyisocyanates. The isocyanate reactive group may also comprise a single isocyanate reactive group or multiple isocyanate reactive groups. The components of the polyisocyanate and the organic material having the isocyanate reactive group may each be provided separately, or may be provided in a pre-mix. Preferably, the polyisocyanate is a polyfunctional polyisocyanate having an NCO functionality of an average of 2.5 to 5. More preferably, the polyisocyanate is a free polyisocyanate. The polyisocyanate may additionally be a (cyclo)aliphatic, araliphatic or aromatic polyisocyanate. In particular, the polyisocyanate comprises a biuret, urethane, uretdione and/or isocyanurate derivative. Examples of polyisocyanates of the present invention are 1,6-diisocyanatohexane, isophorone diisocyanate, 2,4-toluene diisoyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, 4,4'-bis(isocyanato-cyclohexyl) methane, 1,4-diisocyanatobutane , 1,5-diisocyanato-2,2-dimethylpentane, 2,2,4-trimethyl-1,6-diisocyanatohexane, 1,10-diisocyanatodecane, 4,4-diisocyanato-cyclohexane, 2,4-hexahydrotoluenediiso -cyanate, 2,6-hexahydrotoluene diisocyanate, norbornane diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene-

diisocyanate, 1-isocyanato-3-(isocyanatomethyl)-1-methyl-cyclohexane, m-a,a-a',a'-tetramethylxylylene diisocyanate, and derivatives and/or mixtures thereof. These products are generally liquid at ambient temperature and commercially available.

Preferably, the isocyanate reactive group is a thiol group. Alternatively, the isocyanate reactive group may also be a resin having as the backbone, for example a polyester, polyurethane, polyacrylate and/or polyether resin.

According to a preferred embodiment, the polymerization component of the varnish sealant and the isocyanate reactive group is provided in a volatile organic solvent and the method comprises the step of deaerating the applied varnish layer. Preferably, the volatile organic solvent of both components is n-butyl acetate. Depending on the desired final finish of the substrate surface, a lacquer layer can also be applied to the substrate surface before applying the varnish layer. The varnish layer is then applied to this lacquer layer. For a better adhesion of the lacquer, a primer is preferably first applied to the substrate surface. All types of substrates can be painted.

Preferably, the wood or wood composite substrates are coated with closed pores. Such substrates generally therefore have a less qualitative appearance in comparison with coarse-pored substrates.

DESCRIPTION OF THE FIGURE In what follows, the invention is described by means of. non-limiting figures illustrating the invention, and which are not intended or should be construed to limit the scope of the invention.

Figure 1: Darkroom Figure 1 shows an isometric projection of a preferred embodiment of the darkroom according to the present invention.

The dark space is only partially drawn, i.e. the side and top walls of the dark space are not shown.

The substrate (4) in Figure 1 is provided on a worktop (5). This worktop (5) is carried in via a slot (not shown) in a side wall (not drawn) of the dark room (1) via a rail guide system (6). The slot (not shown) is provided with a cover (not shown), such as for instance a roller shutter which can be rolled up while carrying the substrate (4) in. Once the substrate (4) is in a spraying position (as shown in Figure 1), a layer of varnish is applied to the substrate face (3) by means of a spray bell (2). This spray bell (2) is movable by a motorized arm (7) with rail guide system.

The application of the photo-activatable varnish in the dark space (1) is essential for the applied varnish layer to cure in a controlled and uniform manner.

If the varnish were to be applied in a space that is not, or only partially, darkened, the varnish layer will not adhere sufficiently to the substrate surface (3). This poor adhesion is, for example, characterized by a too low degree of coverage of the varnish layer, breaks, cracks, flakes, etc.

Moreover, in such a situation the varnish can already partially harden or polymerize before it reaches the substrate surface (3) from the spray bell (2).

This again results in a poor adhesion and can also possibly clog a nozzle of the spray bell (2).

The spray clock (2) is controlled by means of the motorized arm (7) with rail guide system on the basis of one or more determined coordinates of the substrate plane (3) in the dark space (1). These coordinates are determined from a camera image of the substrate plane (3) captured by a camera module (not shown). According to the present preferred embodiment, this camera module is configured to capture the camera image in an illuminated space.

For this purpose, the camera module is provided outside the dark room (1). By determining the one or more coordinates for applying the varnish layer in the dark space (1), the varnish can be applied on the substrate plane (3) in a targeted manner. This prevents wastage by blindly applying the varnish in excess.

After applying the varnish layer to the substrate plane (3), the rail guiding system (6) moves the substrate (3) to a slot (8) in a rear wall (9) of the dark space (1). Provided against an outer edge of this slot (8) is a roller system (10) configured to engage the substrate (3) when the rail guide system (6) moves the substrate (3) to the slot (8) in the back wall ( 9) of the dark space (1) moves. This slot (8) is also provided with a cover (not shown), such as for instance a roll-up roller shutter. The roller system (10) can then transport the substrate (4) to a room for UV treatment of the applied varnish layer. If a volatile organic solvent is used in one or more components of the varnish sealant, the applied varnish layer can be vented prior to the UV treatment. This takes place, for example, in a closed room equipped with an extraction system. Previous steps have been described for applying a coat of varnish. In the case of an open-pored substrate (4), the substrate surface (3) can be pretreated with a backfill before applying the varnish. However, the filler for this may be photoactivatable according to the present invention. As a result, the same processing steps, as described above for the varnish layer, must be applied after and before applying this filling ground.

Figure 2: UV Treatment Figure 2 shows an isometric projection of a preferred embodiment of a room for UV treatment of the varnish layer and/or backfill according to the present invention.

The UV treatment room (11) in Figure 2 is closed off for personnel protection. However, this space is only partially drawn, i.e. the side, bottom and top walls of the space are not shown. The substrate (4) provided with a varnish layer or backfill is carried in by means of a roller system (12) via a slot (13) in a rear wall (14) of the space (11). This slot (13) is provided with a cover (not shown), such as for instance a roll-up roller shutter.

In the space (11), two vertically spaced bearing surfaces (15) are provided for supporting the introduced substrates (14) during the UV treatment.

This UV treatment is provided by providing a UV treatment surface (15) parallel to each of these bearing surfaces (15).

Each of these planes (15) consists of a plurality of pivotally mounted panels (16) provided with UV-light-producing lamps (17), such as UV-light-producing fluorescent lamps.

By pivotally mounting these panels (16), these lamps (17) are easily accessible for maintenance.

After the UV treatment, the panels are engaged by a roller system (not shown) to be brought out through a slot (not shown) in a side wall (not shown).

Depending on the UV-treated layer on the substrate face (3), the panels are sanded, polished, etc. after the UV treatment.

Claims (17)

CONCLUSIONS A method for obtaining a high-gloss finish on a substrate suitable for use in manufacturing a cabinet or top, the method comprising the steps of: - providing a substrate substantially made of a wooden material and/or a wooden composite material; - preparing a varnish from a varnish kit comprising o a photoinitiator; and o a polymerization component comprising a curable or polymerizable organic material; wherein the preparation of the varnish is by mixing the components of the varnish kit; - applying a varnish layer with the prepared varnish on a substrate surface, wherein the application of the varnish layer takes place in a substantially dark room; and - exposing the applied varnish layer to a UV treatment for curing or polymerizing the organic material; characterized in that for applying the varnish layer, one or more coordinates of the substrate plane in the substantially dark space are determined from a camera image of the substrate plane and the coordinates of the substrate plane are used to drive a spray clock configured to applying the varnish layer in the substantially dark space. Method according to preceding claim 1, wherein the camera image of the substrate plane is obtained outside the substantially dark space. A method according to any one of claims 1 or 2, wherein the varnish sealant further comprises a reaction compound having an isocyanate reactive group and wherein the organic material comprises a polyisocyanate. A method according to any one of claims 1 to 3, wherein the polymerization component of the varnish sealant is provided in a volatile organic solvent, preferably n-butyl acetate, and wherein the method comprises the step of deaerating the applied varnish layer. A method according to any one of claims 1 to 4, wherein the method, after the UV treatment of the varnish layer, comprises the step of sanding the varnish layer with an abrasive sheet having a grain of at least P1000. A method according to any one of claims 1 to 5, wherein the method, after the UV treatment, comprises the step of polishing the varnish layer with a polishing paste applied with a rotary polishing machine. A method according to any one of claims 1 to 6, wherein the substrate face has open pores and wherein the method of applying the varnish layer comprises the step of filling the substrate face. Method according to preceding claim 7, wherein a backfilling soil is applied to the substrate surface before filling. A method according to any one of the preceding claims 7 or 8, wherein a filling ground is applied to the substrate surface after filling and before applying the varnish layer. A method according to any one of the preceding claims 8 or 9, wherein the method comprises the steps of: - preparing filler from a filler kit comprising: o a photoinitiator; o a reaction compound with an isocyanate reactive group; and o a polymerization component comprising a curable or polymerizable organic material, which comprises a polyisocyanate; wherein the preparation of the filler is by mixing the components of the filler kit and the filler is used for applying the filler; and - exposing the applied backfill to a UV treatment to harden or polymerize the organic material. 11. A method according to claim 10, wherein the filling soil is applied in a substantially dark space. A method according to the preceding claim 11, wherein for arranging the backfill one or more coordinates of the substrate plane in the substantially dark space are determined from a camera image of the substrate plane and wherein the coordinates of the substrate plane are used for controlling a spray bell configured for applying the backfill in the substantially dark space. A method according to any one of claims 10 to 12, wherein the method, after the UV treatment of the backfill, comprises the step of sanding the backfill with an abrasive sheet having a grain of at least P100. A method according to any one of claims 7 to 13, wherein the substrate is a veneer sheet and wherein the substrate face is a major surface of this sheet. A method according to any one of claims 1 to 6, wherein the substrate surface has closed pores and is provided with a primer foil. A method according to any preceding claim 15, wherein the method of applying the varnish layer comprises the steps of: - applying a primer layer to the substrate surface; and - applying a layer of lacquer to the base layer; wherein the varnish layer is applied to the lacquer layer. A method according to any one of the preceding claims 15 or 16, wherein the substrate is a panel and wherein the substrate face is a major surface of this panel.