DE102005002059A1 - Wood material with dissipative surface - Google Patents

Abstract

A panel (A) of wooden material (WM), having a surface coating comprising an undercoat (applied to WM) and at least one lacquer layer (LL) hardened by UV-light or an electron beam (the overall thickness of the LL('s) being less than 120 mu m), includes at least one functional component (I), integrated in LL('s) or in the form of a functional layer which is external, under LL('s) or between at least two LL's. Independent claims are included for: (1) a panel (A') of WM, having a coating of lacquer on at least part of the side opposite to the surface coated; (2) a method for coating WM by applying at least two layers of UV-hardenable lacquer, where the first layer is subjected to UV treatment to start hardening of the lacquer, the second layer(s) is/are applied before the first layer has hardened completely and complete hardening of the second layer(s) using UV light is commenced after applying the last layer; and (3) apparatus for coating (specifically lacquering) panels, in which the panels are transported to and from a processing unit, the coating is applied and the coating is partially or completely hardened, where (a) application and hardening devices arranged in direct succession are combined to a give a processing unit, (b) at least two such processing units are provided and (c) a processing unit for applying functional layer(s) is provided before, between or after processing units for applying at least two LL's.

Description

The The invention relates to a plate-shaped wood material and a Overlay, each coated with a synthetic resin.

With Synthetic resins coated wood-based materials often become common in practice used, for example as floors, wall or ceiling panels, countertops, work surfaces and the like. With synthetic resins Coated overlays suitable for application to wood-based materials are a commonplace Precursor in the production of coated wood materials dar. Due to the resistant surfaces, the itself by the coating of the wood materials directly or resulting from the application of resin impregnated overlays These wooden materials are used both in the living area (kitchens, offices, floors) also for used for commercial purposes. In connection with this invention all products, made of wood or a mixture of wood and plastic are referred to as wood-based materials. Especially typical wood materials are different types of fiberboard or chipboard.

there are subject to some resin-coated wood materials per se only one serious limitation, the static charge, which is made of acting as an insulator Synthetic resin surface yields. In practice, this is particularly disadvantageous in melamine resin-coated Surfaces. In private use, this only means an undesirable or unpleasant property, in commercial use may be the risk the static charge an exclusion criterion for various Uses, especially in environments where a spark due to the risk of explosion.

So far Three different strategies are pursued to solve the static Charging of synthetic resin surfaces to reduce: first became conductive Substances, eg. Soot, mixed into the resin, that on the surface of Wood materials or on overlays is applied. Apart from the difficult processability and pollution problems, in particular when processing z. As soot, which has essentially on "black" limited color the surface practically excluded the practical use in the market.

Alternatively, so-called antistatic agents, mostly surfactants, are mixed into the synthetic resins or applied to their surface. Examples of this mechanism of action are z. B. in the DE 203 18 290 (Kaindl) or WO 2004/050359 (Unilin). These surfactants extract water from the ambient air. The thin molecular mass of water forming around the surfactants is sufficient to ensure minimal charge balance. However, this intrinsically simple and convincing mode of action has two decisive disadvantages in practice: The water flux forming around the surfactants only causes a reduction of the surface resistivity by about one order of magnitude, ie to about 1 × 10 ¹⁰ Ω to 1 × 10 ¹¹ Ω , Thus, the measured values, z. B. to EN 14 041 are required to classify surfaces as conductive, not achievable. Another disadvantage is that the ambient air must have sufficient moisture to form a film of water. However, the problem of static charge is just at low humidity. Antistatic agents do not work exactly when they are needed.

Finally, in the DE 103 01 293 (Blomberger) proposed to embed conductive fabrics in strip form in a synthetic resin layer on the surface of plate-shaped wooden materials. However, the optical degradation of the surface severely limits the usefulness of these conductive fabrics.

It There is therefore a need, a plate-shaped wood material or a Overlay with at least one synthetic resin layer that permanently has a significant improvement in the conductivity given is.

These Task is solved with a plate-shaped Wood material according to claim 1 and an overlay according to claim 10.

core The invention is the incorporation of electrically conductive, transparent Particles in synthetic resin, preferably in transparent synthetic resin. This mixed with transparent, electrically conductive particles resin is then either applied to an overlay or to the surface of a disc-shaped Wood material. According to the invention has pointed out that a single, with small amounts of the said Particle offset layer of synthetic resin is sufficient to be durable and independent of other parameters such as ambient humidity a significant improvement the conductivity to ensure, for example a surface for one dissipative floor in accordance with DIN IEC 61 340.

Transparent conductive particles are produced, for example, by applying metal oxides to carrier particles. For example, a mica particle containing tin and antimony oxide is suitable is doped. Transparent particles may have a platy or spherical shape. Good conductivity and transparency as well as optimum conductivity is achieved with particles having a diameter of up to 25 .mu.m, preferably up to 15 .mu.m, preferably of up to 10 microns.

It was for surprising the expert, permanently a desired one conductivity at very thin Layer structure without sacrificing high mechanical and chemical resistance the invention with particles to achieve offset resin layer.

It is according to the invention sufficient, if in only one layer of a multilayer resin structure on an overlay or a plate-shaped wooden material that electrically conductive, transparent Particles is included. According to the invention, up to 15% by weight (% by weight) suffice electrically conductive, transparent particle based on the solids content of the synthetic resin, preferably up to 10% by weight, more preferably up to 8% by weight Particles based on the solids content of the resin used.

A dissipative surface on an overlay or a plate-shaped wood material is built up if at least one layer, that is to say up to 40 g / m ^{2 of} a synthetic resin mixed with transparent, conductive particles according to the invention, is applied. According to a preferred embodiment, up to 25 g / m ² , more preferably up to 15 g / m ² , advantageously up to 10 g / m ² are sufficient. Overall, the layer structure of the respective surface can easily exceed 100 g / m ² in the case of a multilayer structure. Nevertheless, only one layer of the synthetic resin added according to the invention is sufficient to obtain a surface which has a significantly improved conductivity.

According to an advantageous embodiment, in the case of the synthetic resin of the invention mixed with electrically conductive, transparent particles, a layer thickness of up to 40 .mu.m, preferably up to 20 .mu.m, particularly preferably up to 10 .mu.m, is classified according to EN 1815 as a classification according to EN 14041 as a static surface, which ensures a passenger charge of less than 2 kV. This value is achieved with the inventively applied to an overlay or a plate-shaped wood material, provided with particles of synthetic resin layer. It should be particularly pointed out that this is achieved largely independently of the ambient humidity, that is also at values of, for example, 25% relative humidity. For the first time, with the overlay according to the invention using melamine resin which has been mixed with transparent, electrically conductive particles, a reduction of the surface resistance to values of 2 × 10 ⁰⁸ Ω has been achieved.

The Particle is firmly anchored in the resin. It can therefore be in the extreme Layer of a multi-layer surface to be included. Surprisingly will be the desired conductivity but also achieved when the mentioned particle containing layer in a multi-layered surface structure covered by other synthetic resin layers becomes.

To an advantageous embodiment of the Invention is a transparent resin used, in particular a melamine resin. This will broaden the scope of application the coated according to the invention Overlays or plate-shaped Achieved wood materials, so that this example. also for work surfaces in the electronic industry are suitable. Panels are often used too Design of wall surfaces, so soils, Ceilings or walls used. Here, the coating according to the invention proves to be advantageous because the conductive surface also for at least partial shielding of electromagnetic fields suitable is. she wears thus avoiding impairments by electrosmog.

in the In connection with the invention, the term "overlay" is understood to mean that a carrier Paper or a synthetic fiber scrim at least coated with a synthetic resin layer is that has transparent, electrically conductive particles. overlays become common for coating plate-shaped Wood materials used. Alternatively, wood-based materials become direct with a layered surface structure Mistake. The layered surface according to the invention has at least a synthetic resin into which the electrically conductive, transparent particles are mixed. Optionally, the synthetic resin can also be fibers for formation a so-called "liquid overlays " is called, when using a "liquid overlays "can open Use of the usual Paper-based overlays are dispensed with.

Either in the production of overlays as well as the construction of layered surfaces on plate-shaped wooden materials As a rule, several synthetic resin layers are applied one above the other. To the this simplifies the uniform curing of synthetic resins, and secondly Show the layers frequently a different structure. For example, one is Of the synthetic resin layers often admixed with corundum to the wear resistance the surface to increase. Typically, this happens with floor surfaces.

The multilayer surface of plates shaped wood-based materials often also has a layer with coloring constituents, which is covered by transparent synthetic resin layers. Especially in the case of this surface structure, it becomes clear that the transparency of the electrically conductive particles abolishes restrictions on the use of the plate-shaped wood-based materials which hitherto existed.

details The invention will be explained in more detail with reference to the following embodiments.

1 : Schematic representation of a plate-shaped wood material with a conductive surface coating

example 1

An overlay with a basis weight of 40 g is guided by rollers through a per se known impregnation plant with Quetwalzendosierung. In a bath, through which the overlay is pulled, melamine resin with a solids content of 60% is introduced into the paper. After leaving the bath, the overlay is passed through a pair of rollers on which excess synthetic resin is stripped off. The paper thus impregnated has a weight of 100 g / m ² after intermediate drying.

Subsequently, in each case an additional melamine resin layer of 20 g / m ^{2 is} applied to the top and bottom of the paper in a raster application work. The top side applied melamine resin layer is - with respect to the solids content of the melamine resin - 8 wt .-% transparent, electrically conductive particles added, namely with mica particles, which are doped with tin and antimony, and having a diameter of about 15 microns. The overlay is dried after application of the second melamine resin layer.

The overlay is pressed on a high-density fiberboard on which decorative paper is already applied, under pressure and heat. The resulting surface of the fiberboard has a surface resistivity of 3.0 × 10 ⁰⁸ Ω when tested for electrostatic behavior according to IEC 60093 and EN 1081. If such a coated fiberboard is used as floor, it is classified as "Ableitfähiger floor" according to DIN IEC 61340-4-1: 1997 or as "electrostatic dissipative floor covering" according to EU 14041: 2004-12-20. This classification was previously unattainable when using melamine resins for surface coating of floors.

Of the Test according to EN 1815 results on an insulating base at a person in rubber soles a so-called person voltage of 1.8 kV. This is the fiberboard coated with the above-described overlay as dissipative To classify flooring because the personal voltage of 2 kV is well below.

Example 2

On a medium-density fiberboard 2 will - as in 1 shown - after smoothing the surface by means of paint a decor 4 applied. On the decor 4 Further surface layers are applied, namely a first layer 6 a UV-curing lacquer with a layer thickness of 20 microns, which - based on the solids content of the melamine resin - with 8 wt .-% of the above-described, transparent, electrically conductive particles 10 is provided. After at least partial curing of this paint becomes another layer 12 a UV-curing paint applied with a layer thickness of 20 microns and the paint layers are finally cured. The surface-coated hardboard 2 is with an edge profiling 14a , b provided. It is used as a ceiling or wall panel. 1 shows the individual layers of the surface structure for the sake of clarity not to scale.

This panel has a surface resistance of about 10 ⁰⁸ Ω to 10 ⁰⁹ Ω. It shields electromagnetic fields at least partially. If these panels z. B. laid as wallcovering in rooms that are exposed to electromagnetic fields, so these fields behind the panels, so in the rooms, only weakened or no longer perceived.

Example 3

A decorative paper intended for use on a countertop is made by impregnating a backing paper with a melamine resin decor print. On this impregnated paper is then - as described in Example 1 - a melamine resin layer which - based on the solids content of the melamine resin with 10 wt .-% of the particles described in Example 1 is added, and with 40 g / m ^{2 is} applied to the preimpregnated paper. The decorative paper with a conductive top surface thus produced is pressed onto a chipboard.

This chipboard is suitable for use as a worktop, in particular in the electronic industry, since the surface resistance of the melamine resin coating thus produced is 10 ⁰⁷ Ω to 10 ⁰⁹ Ω. Sensitive electronic components that are damaged or destroyed by stronger electrical discharges can be stored or processed on these easily and inexpensively manufactured surfaces.

Claims (19)

Plate-shaped wood material ( 2 ) having a layer-shaped surface, wherein the surface at least - a synthetic resin, which is optionally mixed with fibers and - at least one type of particles, characterized in that the synthetic resin with electrically conductive, transparent particles ( 10 ) is offset. Plate-shaped wood material according to claim 1, characterized in that the proportion of particles ( 10 ) Up to 15 wt .-% based on the solids content of the synthetic resin used, preferably up to 10 wt .-%, particularly preferably up to 8 wt .-% based on the solids content of the resin used. Plate-shaped wood material according to claim 1, characterized in that the particle-added synthetic resin in an application amount of up to 40 g / m ² , preferably of up to 25 g / m ² , more preferably up to 15 g / m ² , advantageously up to 10 g / m ^{2 is} applied to the plate-shaped wood material. Plate-shaped wood material according to claim 1, characterized in that the particles ( 10 ) offset resin is applied as a layer having a thickness of up to 30 .mu.m, preferably of up to 20 .mu.m, more preferably of up to 10 .mu.m on plate-shaped wood material. panel-form Wood material according to claim 1, characterized in that a transparent resin is used. panel-form Wood material according to claim 5, characterized in that melamine resin is used as a synthetic resin. panel-form Wood material according to claim 1, characterized in that the surface the wood material has at least one further layer. panel-form Wood material according to claim 1, characterized in that, the Surface one another layer has, which has a synthetic resin, mixed in the corundum is. panel-form Wood material according to claim 1, characterized in that the surface of the wood material has at least one further layer, the having coloring ingredients. Overlay, impregnated with at least one layer of synthetic resin coated with an electrically conductive, transparent particle ( 10 ) is offset. Overlay according to claim 10, characterized that the proportion of particles (10) up to 15 wt .-% based on the Solids content of the synthetic resin used, preferably up to 10% by weight, particularly preferably up to 8 wt .-% based on the solids content of the synthetic resin used. Overlay according to claim 10, characterized in that with particles ( 10 ) offset resin in an application amount of up to 40 g / m ² , preferably of up to 25 g / m ² , more preferably up to 15 g / m ² , advantageously up to 10 g / m ^{2 is} applied to the overlay. Overlay according to claim 10, characterized in that with particles ( 10 ) offset resin as a layer ( 12 ) is applied to the overlay with a thickness of up to 30 .mu.m, preferably of up to 20 .mu.m, more preferably of up to 10 .mu.m. Overlay according to claim 10, characterized that the synthetic resin is transparent. Overlay according to claim 14, characterized that melamine resin is used as synthetic resin. Overlay according to claim 10, characterized in that in addition to the with an electrically conductive, transparent particles ( 10 ) offset resin layer ( 12 ) at least a second synthetic resin layer is applied to the overlay. Overlay according to claim 16, characterized that the second resin layer is mixed with corundum. panel-form Wood material according to at least one of claims 1 to 9, characterized that the plate-shaped Wood material as floor panel, is designed as a wall panel or as a ceiling panel. Overlay according to one of Claims 10 to 17, characterized that it is used for coating on a plate-shaped wood material.