Coated board of wood-based material

Abstract

The present application relates to a coated board of wood-based material and a method for coating a board of wood-based material, wherein the board of wood-based material is in particular a wall panel or floor panel or is intended for producing such a panel, comprising a front side and a rear side, wherein at least the surface of the front side is provided with a polymer coating and wherein the polymer coating has a hardness gradient, so that the hardness of the polymer layer decreases with increasing depth from the surface.

1 . Coated board of wood-based material, in particular a wall, ceiling or floor panel, comprising a front side and a rear side, wherein at least the surface of the front side is provided with a polymer coating, characterised in that the polymer coating has a hardness gradient, so that the hardness of the polymer coating substantially continuously decreases with increasing depth viewed from the surface of the coating. 
   
   
       2 . Coated board of wood-based material according to  claim 1 , characterized in that the hardness gradient substantially corresponds to the following formula:
   (−3.0 *x )+ C<=Y ( x )<=(−0.2 *x )+ C      wherein:   x is the absolute value of the depth in μm of the coating viewed from the surface of the coating;   Y(x) is the absolute value of the hardness in N/mm 2  at a certain depth x; and   C is the absolute value of the initial hardness in N/mm 2  of the coating at a depth of approximately x≈0-5 μm.   
   
   
       3 . Coated board of wood-based material according to  claim 1 , characterized in that the hardness gradient substantially corresponds to the following formula:
   (−2.5 *x )+ C<=Y ( x )<=(−0.4 *x )+ C      wherein:   x is the absolute value of the depth in μm of the coating viewed from the surface of the coating;   Y(x) is the absolute value of the hardness in N/mm 2  at a certain depth x; and   C is the absolute value of the initial hardness in N/mm 2  of the coating at a depth of approximately x≈0-5 μm.   
   
   
       4 . Coated board of wood-based material according to  claim 1 , characterized in that the hardness gradient substantially corresponds to the following formula:
   (−2.0 *x )+ C<=Y ( x )<=(−0.6 *x )+ C      wherein:   x is the absolute value of the depth in μm of the coating viewed from the surface of the coating;   Y(x) is the absolute value of the hardness in N/mm 2  at a certain depth x; and   C is the absolute value of the initial hardness in N/mm 2  of the coating at a depth of approximately x≈0-5 μm.   
   
   
       5 . Coated board of wood-based material according to  claim 1 , characterised in that the board is a chip board, MDF board, HDF board, OSB board or real wood board. 
   
   
       6 . Coated board of wood-based material according to  claim 1 , characterised in that the polymer coating consists of polymers which are curable by means of radiation. 
   
   
       7 . Coated board of wood-based material according to  claim 1 , characterised in that the polymer coating has a initial Martens hardness at a depth of approximately 0-5 μm from 120 N/mm 2  to 250 N/mm 2  measured according to DIN ISO 14577. 
   
   
       8 . Coated board of wood-based material according to  claim 1 , characterised in that the polymer coating has a initial Martens hardness at a depth of approximately 0-5 μm from 130 N/mm 2  to 200 N/mm 2  measured according to DIN ISO 14577. 
   
   
       9 . Method for coating a board of wood-based material, comprising the following steps:
 a) providing a board of wood-based material;   b) applying a first liquid coating means;   c) applying at least a second liquid coating means onto the still wet first coating means, so that a partial mixture of the coating means take place;   d) curing of the applied coating means by means of radiation wherein the coating means are selected so that the cured resultant coating has a hardness gradient wherein the hardness of the coating decreases with increasing depth viewed from the surface of the resultant coating.   
   
   
       10 . Method for coating a board of wood-based material according to  claim 9 , characterised in that prior to step d) further coating means are applied onto the still wet pre-applied coating means. 
   
   
       11 . Method for coating a board of wood-based material according to  claim 9 , characterised in that the hardness gradient substantially corresponds to the following formula:
   (−3.0 *x )+ C<=Y ( x )<=(−0.2 *x )+ C      wherein:   x is the absolute value of the depth in μm of the coating viewed from the surface of the coating;   Y(x) is the absolute value of the hardness in N/mm 2  at a certain depth x; and   C is the absolute value of the initial hardness in N/mm 2  of the coating at a depth of approximately x≈0-5 μm.   
   
   
       12 . Method for coating a board of wood-based material according to  claim 9 , characterised in that the hardness gradient substantially corresponds to the following formula:
   (−2.5 *x )+ C<=Y ( x )<=(−0.4 *x )+ C      wherein:   x is the absolute value of the depth in μm of the coating viewed from the surface of the coating;   Y(x) is the absolute value of the hardness in N/mm 2  at a certain depth x; and   C is the absolute value of the initial hardness in N/mm 2  of the coating at a depth of approximately x≈0-5 μm.   
   
   
       13 . Method for coating a board of wood-based material according to  claim 9 , characterised in that the hardness gradient substantially corresponds to the following formula:
   (−2.0 *x )+ C<=Y ( x )<=(−0.6 *x )+ C      wherein:   x is the absolute value of the depth in μm of the coating viewed from the surface of the coating;   Y(x) is the absolute value of the hardness in N/mm 2  at a certain depth x; and   C is the absolute value of the initial hardness in N/mm 2  of the coating at a depth of approximately x≈0-5 μm.   
   
   
       14 . Method for coating a board of wood-based material according to  claim 9 , characterised in that the first and the second layers are polymer layers, wherein the second polymer layer comprises more C—C double bonds than the first polymer layer. 
   
   
       15 . Board of wood-based material coated by means of a method according to  claim 9 . 
   
   
       16 . Using a coated board of wood-based material according to  claim 1  as wall, ceiling or floor panel.