EP2219883B1 - Multilayer composite plate - Google Patents

Description

The present invention relates to a composite panel and a panel comprising this composite panel.

Multilayer composite panels, also called laminate panels or laminates, are used today in many areas of life for utility and decoration purposes. For example, they are used in interior design for cladding windows, stairs and floors, and in the coating of furniture in both private and commercial areas.

Multilayer composite panels usually consist of a certain number of different sheets of paper, which are impregnated with curable synthetic resins, stacked on top of each other and pressed together under heat and high pressure by means of press plates (often referred to as press plates). The core of these composite panels is usually an array of sheets of kraft paper on which a sheet of decor paper decorated with patterns or colors is usually placed. Finally, a usually transparent overlay can be attached to the decorative paper sheet. High-pressure laminates (HPLs) produced in this way are sold, for example, under the trade name Resopal.

Multilayer composite panels are often processed into panels, such as floor panels, which are used as interior or exterior floor coverings of buildings. The floor panels serve as a permanent footboard and footprint and are therefore exposed to high mechanical stresses.

For this reason, multilayer composite panels, especially when they are processed into floor panels, have a high resistance to mechanical Stress, in particular a high abrasion resistance, have. European Standard 13329, Annex E, specifies a test for determining the abrasion resistance of laminate flooring and the classification of the tested laminate flooring in abrasion classes from AC1 (moderately abrasion-resistant at home) to AC5 (highly abrasion-resistant in the commercial sector).

A high abrasion resistance of surfaces of composite panels or laminate flooring having these composite panels is achieved, in particular, by incorporating into the composite panels corundum particles which are naturally characterized by a high degree of hardness. The abrasion resistance can be controlled in particular by the size and the amount of corundum particles used.

To increase the abrasion resistance of laminate surfaces suggests the EP 0329154 prior to bonding a resin impregnated and coated with hard particles paper sheet with a laminate base layer. The paper sheet should be provided on at least one side with 2 to 20 g / m ² , preferably 3 to 12 g / m ² hard particles. According to this document, unacceptable fog formation is observed at levels of more than 20 g / m ² of hard particles.

Another decisive criterion for the quality of composite panels is not only the abrasion resistance but also the gloss level of the surface. The high gloss of the surface, which is usually desired by the user, is decisively determined by the type of cured binder lying on the surface of the composite panel. Furthermore, for example, from the EP 0826790 It is known that the gloss level of the surface of composite panels also depends on the surface finish of the press plate used for the compression of the composite panels. For example, smooth, high-gloss press plates can be used to produce composite panels with a high-gloss surface.

However, in the prior art there is the problem that composite panels having a high gloss, by the choice of a suitable, the gloss-imparting binder or the use of press plates with high-gloss surface, although However, this gloss quickly fades with regular mechanical stress of these composite panels. Especially in the application in the floor area gives such a rapid fading the impression of heavy wear, which is not desired by the consumer and also not accepted.

To increase the gloss resistance of laminate surfaces suggests the EP 0136577 to provide the outer portion of the laminate surface with mineral particles having a size of 5 to 100 nm. Although the surface of a laminate thus produced has improved gloss retention, the surface is not given high abrasion resistance by the use of these relatively small particles.

EP 0219 769 B1 describes a decorative laminate and a method of making such a laminate. The decorative sheet of the laminate is coated with particulate abrasive material having a hardness greater than that of silica. Of the abrasive material 0.2 to 10 g / m ² , preferably 4 to 6 g / m ² applied. For orders of more than 10 g per square meter, the appearance of the surface may be dim. The resistance of the laminate surface to scratching was tested by measuring the loss of gloss after shearing. The 10 post double rub gloss loss using 3M Scotch Brite type 8A Abrasive Pads is 4%.

AT 40 807 E claims a decorative laminate bonded by heat and pressure, the outermost surface of the laminate containing mineral particles having a Mohs hardness of at least 5 and present in an amount in the range of 0.5-25 g / m ² . With a higher concentration of mineral particles, the laminates often become cloudy and lose their shine. Luster loss after scrubbing with 10 double strokes using 3M Scotch Brite type 8A abrasive pads is approximately 5%.

DE 103 55 180 A1 relates to a decorative laminate, a decorative laminate panel, and a method for producing the decorative laminate. The decorative laminate consists of a decorative layer and a protective layer firmly connected to the decorative layer, which consists of a mixture of at least one heat-hardened synthetic resin, hard particles (Mohs hardness at least 5) and at least one wax. The addition of the wax has a favorable effect on the tool stress, in particular in the manufacturing process. Furthermore, a preferred embodiment is described which contains no hard particles in the decorative sheet or the coating sheet. This will give you a better visual impression of the pattern. No wear and abrasion tests were performed.

EP 0 875 399 A2 relates to a decorative laminate with abrasion-resistant surface coating. In the wear layer, the particles of the hard material, such as corundum are distributed. The wear layer contains a corundum loading of 69g / m ² . This is achieved by special additives in the resin matrix. There is no information on the gloss and gloss retention of the laminates.

DE 197 10 619 A1 relates to solid particles coated with melamine resin, wherein the hardness of the solid particles according to Mohs is at least 7. Furthermore, the invention relates to aqueous impregnating solutions which contain these coated solid particles and other substances, such as are customary in solutions which are suitable for the production of overlay and decorative films, and the overlay and decorative films produced therewith. There is no information on the gloss and the gloss resistance of the laminates.

WO 2005/042 644 A1 describes a decorative paper with scattered abrasion-resistant particles. Overlay and decorative paper are preferably combined and pressed so that the abrasion-resistant particles form an intermediate layer. There is no information on the gloss and gloss retention of the laminates.

DE 1 629 426 A describes abrasion resistant decorative laminates, characterized in that the resin composition of the surface layer contains finely divided material having a hardness of at least 9 on the Mohs hardness scale. There is no information on the gloss and gloss retention of the laminates.

WO 2008/128702 A1 is a document under Art. 54 (3) EPC and discloses a wear shield containing hotshot particles on an HDF board.

Composite panels are therefore known from the prior art whose surfaces show increased abrasion resistance or increased gloss retention.

However, it has not yet been possible to produce composite panels whose surfaces have both excellent abrasion resistance and excellent gloss retention.

The present invention is therefore based on the object to provide a composite panel whose surface is characterized by excellent gloss retention and high abrasion resistance.

This object is achieved according to a first higher inventive idea by a composite panel as defined in claim 1.

This object is also achieved according to a further superior inventive idea by a composite plate as defined in claim 2.

In the core layer of the composite panel according to the invention one or more sheets of kraft paper are included.

According to DIN 6730, the kraft paper used in the present invention is a paper which consists predominantly of Kraft pulp, to which Kraft paper can be added, and which has a high strength, in particular a high tensile strength, and a high resistance. Kraft paper is usually made from at least 90 percent fresh, preferably unbleached sulphate pulp (kraft pulp). In addition, kraft paper may contain starch, alum and / or glue in addition to the pulp in order to achieve, for example, certain surface effects and increases in strength. For the purposes of the present invention has kraft paper with a grammage of 150 - proved to 300 g / m ^2, in particular 220-270 g / m ² to be particularly advantageous. A preferred kraft paper is soda kraft paper familiar to those skilled in the art of HPL.

The number of kraft paper sheets used depends essentially on the desired thickness of the core layer or composite panel. Preferably, the composite panel of the present invention contains one to eight sheets, more preferably 3 to 7 sheets, and more preferably 4 to 6 sheets of kraft paper.

The weight of the kraft paper used in the invention is not further limited. It depends in particular on the number of kraft paper sheets used and thus on the desired thickness of the composite panel. According to a preferred embodiment, the weight of the kraft paper sheets used is in the range of 125 to 250 g / m ² , preferably 140-230 g / m ² .

According to a preferred embodiment, the final thickness of the composite panel according to the invention is in the range of 0.75 to 0.85 mm, preferably 0.8 mm. In this case, it may be preferable to use 4 kraft paper sheets weighing from 125 to 175 g / m ² , preferably 150 g / m ² . On the other hand, it is also possible to use 3 kraft paper sheets which have a weight in the range from 200 to 240 g / m ² , preferably in the range from 215 to 240 g / m ² .

According to a further preferred embodiment, the final thickness of the composite panel according to the invention is in the range of 0.95 to 1.05 mm, preferably 1.0 mm. In this case, it may be preferable to use 5 kraft paper sheets having a weight of 125 to 175 g / m ² , preferably 150 g / m ² . On the other hand, it is also possible to use 4 kraft paper sheets which have a weight in the range from 200 to 240 g / m ² , preferably in the range from 215 to 240 g / m ² .

According to yet another preferred embodiment, the final thickness of the composite panel according to the invention is in the range of 1.15 to 1.25 mm, preferably 1.2 mm. In this case, it may be preferable to use 6 kraft paper sheets having a weight of 125 to 175 g / m ² , preferably 150 g / m ² . On the other hand, it is also possible to use 5 kraft paper sheets which have a weight in the range from 200 to 240 g / m ² , preferably in the range from 215 to 240 g / m ² .

On one side of the kraft paper-formed core layer of the multilayer composite panel according to the invention, a decorative layer is applied which comprises a sheet of decorative paper.

Through this layer of decorative paper decorative multilayer composite panel according to the invention receives its appearance. Accordingly, the decorative layer designates that layer applied to the core layer whose pattern can be visually perceived by the viewer.

As used herein, decorative paper refers to any material that is suitable for bonding to the underlying core layer and, optionally, the overlying overlay layer, and that can render a décor. The preferred material for decor paper is paper. However, also films, for example plastic films, or veneers can be covered by the term decorative paper. Veneers are Wood leaves, which usually have a thickness of 0.1 to 3 mm and the decorative layer can give a wooden look, for example, a certain grain.

Usually, the decor is applied to the decorative paper by means of a printing process. Thus, for example, by means of photographic reproduction, any desired motif can be created and imprinted on the decor paper in gravure printing. For example, the motif may consist of wood, stone, ceramic, color and / or fantasy patterns. Furthermore, the motif can also be done by painting the decor paper with one or more colors.

The basis weight of the decorative paper used is not further limited. The basis weight is preferably in the range from 40 to 120 g / m ² , more preferably in the range from 60 to 100 g / m ² , in particular from 70 to 90 g / m ² .

Optionally, further layers, such as an underlay layer, may be arranged between the core layer and the decorative layer. For example, this underlay layer may serve to prevent distortion of the composite panel or to reduce electrostatic charges. Preferably, the underlay layer comprises one or more sheets of kraft paper.

If the composite panel has an overlay layer, then this preferably forms the cover layer for the multilayer composite panel according to the invention and is applied to the decorative layer. The overlay layer comprises one or more sheets of a preferably fibrous material.

The basis weight of the sheets used for the overlay layer is not further limited. It is preferably in the range of 12 to 40 g / m ² , more preferably in the range of 20 to 35 g / m ² and even more preferably in the range of 25 to 32 g / m ² .

The overlay material preferably has a high resistance to chemical, thermal and mechanical stress. If fibrous material is used to make the overlay, then it contains fibrous material preferably bleached pulp fiber, in particular cellulose, for example α-cellulose. The overlay material is preferably of a nature which ensures that the motif of the decorative paper layer underlying the overlay is visible after being pressed into the decorative, multilayer composite material according to the invention. Therefore, the overlay preferably has a high degree of transparency.

The particles contained in the composite panel according to the invention have a Mohs hardness of at least 8, preferably at least 8.5, and more preferably at least 9.

The particles are preferably particles of corundum (aluminum oxide), silicon carbide, aluminum boride, boron carbide or mixtures thereof. Particularly preferred are corundum particles, in particular particles of corundum. The corundum particles can for example be predominantly sharp-edged or cubic and are preferably predominantly cubic.

The particles may be surface-treated in a manner known to those skilled in the art. For example, the particles may have a coating with silane compounds. Preferably, however, the particles are uncoated.

The particles having a Mohs hardness of at least 8 preferably have a certain particle size distribution, which is determined according to the FEPA standard 42-2: 2006. In this standard, inter alia d3 values, d94 values and D50 values are defined, whereby the D50 value indicates the mean particle size of the particles. The mean grain size is grain size, in which 50 percent of the particles have a particle size smaller and 50 percent of the particles have a particle size greater than the mean grain size.

The mean particle size D50 of the particles used having a Mohs hardness of at least 8 is in the range of 5 to 100 μm, more preferably in the range of 5 to 75 μm, even more preferably in the range of 12 to 75 μm, in particular in the range of 45 to 75 μm, for example at 68 μm.

The maximum d3 value is preferably above the average particle size of the particles, for example 1.4 to 2.2 times, more preferably 1.5 to 2.2 times, even more preferably 1.5 to 2, 0 times, and more preferably 1.5 to 1.8 times above the average particle size of the particles. For example, the maximum d3 value may be in the range of 10 μm to 156 μm, more preferably in the range of 10 μm to 118 μm, even more preferably in the range of 23 μm to 118 μm, in particular in the range of 72 μm to 118 μm.

The minimum d94 value is preferably below the mean grain size of the particles, and is, for example, 0.20 to 0.68 times, more preferably 0.23 to 0.65 times, still more preferably 0 , 34- to 0.65-fold, and more preferably from 0.60 to 0.65 times the mean particle size of the particles. For example, the minimum d94 value may be in the range of 1 μm to 65 μm, more preferably in the range of 1 μm to 50 μm, even more preferably in the range of 5 μm to 50 μm and in particular in the range of 25 μm to 50 μm ,

Particles which have an average particle size D50 in the range from 45 μm to 75 μm, preferably in the range from 63 μm to 73 μm, in particular from 68 μm, may be preferred according to the invention. The maximum d3 value may then preferably be in the range from 70 μm to 120 μm, more preferably in the range from 96 to 115 μm, and in particular at 105 μm. The minimum d94 value in this case may preferably be in the range from 28 μm to 49 μm, more preferably in the range from 40 μm to 48 μm, in particular at 44 μm. For example, it is thus possible to use particles of the ZWSK 220 type, the number following the designation "ZWSK" for the particle size designation being in mesh.

However, particles may also be preferred which have an average particle size in the range from 42 μm to 50 μm, more preferably in the range from 45 μm to 50 μm, and in particular 47.5 μm. The maximum d3 value may then preferably be in the range from 65 μm to 78 μm, more preferably in the range from 70 μm to 78 μm, and in particular at 74 μm. The minimum d94 value in this case can be in the range from 25 μm to 31 μm, more preferably in the range from 28 μm to 31 μm, and in particular at 30 μm. For example, it is therefore possible to use particles of the ZWSK 240 type.

Particles which have an average particle size in the range from 35 μm to 40 μm, more preferably in the range from 37 to 40 μm, and in particular from 39.9 μm, may also be preferred. The maximum d3 value may then preferably be in the range from 56 μm to 65 μm, more preferably in the range from 60 μm to 64 μm, and in particular at 64 μm. The minimum d94 value in this case may be in the range from 20 μm to 26 μm, more preferably in the range from 22 μm to 26 μm, and in particular at 26 μm. For example, particles of the type ZWSK 280 can therefore be used.

According to another variant, it is also possible to use particles which have an average particle size in the range from 27.5 μm to 33.5 μm, more preferably in the range from 30 μm to 33 μm, and in particular at 32.8 μm. The maximum d3 value may then preferably be in the range from 46 μm to 55 μm, more preferably in the range from 49 μm to 55 μm, and in particular at 54 μm. The minimum d94 value in this case can be in the range from 14.5 μm to 20 μm, more preferably in the range from 17 μm to 19.5 μm, and in particular at 19.5 μm. For example, particles of the ZWSK 320 type can therefore be used.

According to a further variant, it is also possible to use particles which have an average particle size in the range from 21 μm to 27 μm, more preferably in the range from 24 μm to 27 μm, and in particular at 26.7 μm. The maximum d3 value may then preferably be in the range from 37 μm to 47 μm, more preferably in the range from 42 μm to 47 μm, and in particular at 46 μm. The minimum d94 value in this case may be in the range of 9 to 15.5 μm, more preferably in the range of 12.5 μm to 15.0 μm, and in particular 14.5 μm. For example, particles of the ZWSK 360 type can therefore be used.

Furthermore, mixtures of the corundum particle types mentioned above can also be used.

The particle sizes specified above are particularly preferred when the composite panel according to the invention is to be used for floor applications. When the composite panel according to the invention is used in other areas, especially where scuff-resistant surfaces are desired, such as tables or countertops, the average particle size of the particles is preferably in the range of 12.5 microns to 28 microns and more preferably in the range of 17 to 27 μm. The maximum d3 value is preferably in the range from 24 μm to 48 μm and particularly preferably in the range from 31 μm to 47 μm. The minimum d94 value is preferably in the range of 5 μm to 15.5 μm and particularly preferably in the range of 7.5 μm to 15.5 μm.

It may therefore be preferred particles having a mean grain size in the range of 21 microns to 27 microns, more preferably in the range of 24 microns to 27 microns, and in particular at 26.7 microns. The maximum d3 value may then preferably be in the range from 37 μm to 47 μm, more preferably in the range from 42 μm to 47 μm, and in particular at 46 μm. The minimum d94 value in this case may be in the range of 9 to 15.5 μm, more preferably in the range of 12.5 μm to 15.0 μm, and in particular 14.5 μm. For example, particles of the ZWSK 360 type can therefore be used.

Particles which have a mean particle size in the range from 16.3 μm to 22 μm, more preferably in the range from 17 μm to 22 μm, and in particular at 21.4 μm, may also be preferred. The maximum d3 value may then preferably be in the range from 30 μm to 40 μm, particularly preferably in the range from 32 μm to 40 μm, and in particular at 37 μm. The minimum d94 value in this case may be in the range of 7 μm to 12 μm, more preferably in the range of 8 μm to 12.0 μm, and in particular 21 μm. For example, it is therefore possible to use particles of the ZWSK 400 type.

Particles which have an average particle size in the range from 11.8 μm to 17.5 μm, more preferably in the range from 12.5 μm to 17.5 μm, and in particular at 17.14 μm, may also be preferred. The maximum d3 value may then preferably be in the range from 23 μm to 33 μm, particularly preferably in the range from 24 μm to 33 μm, and in particular at 31 μm. The minimum d94 value in this case can range from 4 μm to 8.5 μm, more preferably in the range from 4.5 μm to 8.0 μm, and in particular at 7.5 μm. For example, it is therefore possible to use particles of the ZWSK 500 type.

The composite panel according to the invention has a binder arrangement in which the core layer and the decorative layer are provided and which forms a binder layer arranged on the decorative layer which contains the particles having a Mohs hardness of at least 8

The binder assembly according to the invention contains at least one, but preferably at least two different binders in the cured state. By means of this at least one cured binder, the individual sheets of kraft paper are interconnected and the core layer formed from the kraft paper sheets and the decorative layer are joined together. The decorative layer is applied to the core layer formed from kraft paper sheets. On the decorative layer in turn is a cured binder layer containing the particles having a Mohs hardness of at least 8.

According to a preferred embodiment, the binder, which in the cured state bonds the kraft paper sheets together and the core layer composed of the kraft paper sheets to the decorative layer, is a thermosetting resin. Preferred binders are liquid or liquefiable resins which cure on their own or with reactants, for example hardeners or accelerators, without elimination of volatile components by polymerization or polyaddition via crosslinking reactions to thermosets. Phenol resins have proved to be particularly preferred for this purpose. Phenolic resins are defined according to DIN 16916, Part 1 and ISO 10082 as condensation products of phenols and aldehydes. Unsubstituted phenol and formaldehyde are the main raw materials for the production of phenolic resins. For details of the chemistry of phenolic resins, reference is made to the following literature: A. Gardziella, LA Pilato, A. Knop, "Phenolic Resins", Springer Verlag, Berlin, Heidelberg, New York, Tokyo, 1999 ; A. Gardziella, HG Haub, "phenolic resins" in: Plastic Handbook, Volume 10, "Duroplasts", p. 12-40, Carl Hanser Verlag, Munich, Vienna, 1988 ; P. Adolphs, E. Giebeler, P. Stäglich, "Houben-Weyl, Methods of Organic Chemistry", Vol. E20, Part 3, pp. 1974-1810.4. Edition, Georg Thieme Verlag, Stuttgart , In a most preferred embodiment, phenol-formaldehyde resin is used as the binder for the kraft paper sheets.

The binder which, when cured, bonds the decorative layer to the core layer and forms the binder layer containing the particles having a Mohs hardness of at least 8 is also preferably a thermosetting resin. For the purposes of the present invention, the use of aminoplasts has proved to be advantageous for this purpose. Aminoplasts are polycondensation products of carbonyl compounds, preferably aldehydes, such as formaldehyde, or ketones, and compounds containing NH groups, such as urea, melamine, urethanes, cyanide or cyanamide, aromatic amines and sulfonamides, which are linked together in a Mannich reaction and harden to thermosets during use. Preferred aminoplasts are urea resins, melamine resins, urethane resins, cyanide or cyandiamide resins, aniline resins and sulfonamide resins. The use of melamine-formaldehyde resins has proven to be particularly preferred. These are hardenable condensation products of melamine and formaldehyde. Furthermore, melamine-urea-formaldehyde resins may also be preferred.

According to another embodiment, the composite panel of the present invention also includes an overlay layer disposed on the decorative layer. In this embodiment, the binder layer containing the particles having a Mohs hardness of at least 8 is not formed on the decorative layer but on the overlay layer. In this case, it is preferable that the binder which in the cured state bonds the overlay layer to the decorative layer and forms the binder layer containing the particles having a Mohs hardness of at least 8, one of the above-described thermosetting resins, particularly preferably one of aminoplasts as described above, such as a melamine-formaldehyde resin or a melamine-urea-formaldehyde resin. It is preferred if for bonding the decorative layer to the core layer, for bonding the overlay layer to the decorative layer and for forming the binder layer containing the particles having a Mohs hardness of at least 8, the same binder, preferably one of thermosetting resins described above, more preferably one of the above-described aminoplasts, such as a melamine-formaldehyde resin or a melamine-urea-formaldehyde resin.

If an underlay layer is provided between the core layer and the decorative layer, then the binder which optionally connects the underlay sheets to one another, the core layer to the underlay layer and the underlay layer to the decorative layer, preferably one of the above-described thermosetting resins, particularly preferably one of those described above Aminoplasts, such as a melamine-formaldehyde resin or a melamine-urea formaldehyde resin.

It is clear to the person skilled in the art that, in particular at the interfaces of individual layers, such as the interface between the core layer and the decorative layer, mixing of the binders used can occur and the boundaries between the individual layers are usually not affected by the binder used, but especially by the outermost, the individual layers forming sheets are defined.

The loading of the binder layer in the binder arrangement of the composite panel according to the invention with the particles having a Mohs hardness of at least 8, based on the surface of the composite panel, in the range of 21 to 35 g / m ² , preferably in the range of 22 to 32 g / m ² and even more preferably in the range of 23 to 29 g / m ² . Surprisingly, it has been found that, in spite of this high loading of the composite panel with the particles having a Mohs hardness of at least 8, there is no actual expected fogging on the visible surface of the composite panel.

The composite panel according to the invention is obtained by producing a structure which contains the kraft paper sheets, the decorative paper sheet and optionally the overlay sheet, as well as the particles and a suitable binder system, this structure between special press plates brings, presses and the binder system hardens.

Binder system according to the invention is understood to mean a single suitable binder or a combination of suitable binders. Suitable binders are preferably to be understood as meaning those binders which have been described above as being preferred for bonding the individual layers contained in the composite board or for joining the sheets forming the layers.

Although the following is referred to as "the" decorative paper sheet or "the" overlay sheet, it is understood by the person skilled in the art that, depending on the desired composition of the composite panel, it is also possible to use a plurality of decorative paper sheets or overlay sheets. The construction of the composite panel or of the construction comprising a plurality of decorative paper sheets or overlay sheets is obvious to the person skilled in the art from the following statements.

According to the invention, the particles described above having a Mohs hardness of at least 8 are applied to the (uppermost) decorative paper sheet or, if an overlay layer is desired, to the (uppermost) overlay sheet. The application of the particles always takes place at least on the outside of the uppermost decorative paper sheet or, if present, at least on the outside of the uppermost overlay sheet. As used herein, the outside of a sheet means that surface of said sheet which is not in contact with any other sheet of the construction. As used herein, the attribute "uppermost" in connection with said signature means that arc of the respective layer farthest from the core paper sheets.

Particulate application may be by any of the conventional techniques such as the wet-on-wet process (see, for example, U.S. Pat EP 122396 . EP 693030 ), the dry-on-wet process (see for example EP 1011969 . EP 837771 . US 4940503 ) or the wet-on-dry process. In the wet-on-wet process, a suspension containing, in addition to the particles, a suitable binder or water is applied to the outside of the topmost decor paper sheet or overlay sheet impregnated with a suitable binder. In the dry-on-wet process, the particles are in the dry state without the addition of binders on the outside of the top, impregnated with a binder decor paper sheet or Overlay sheets applied. In the wet-on-dry process, a suspension which contains a suitable binder in addition to the particles is applied to the outside of the uppermost, dry, unimpregnated decor paper sheet or overlay sheet.

The mass of the particles to be applied having a Mohs hardness of at least 8 is determined by the desired loading of the composite panel with these particles and is accordingly 21 to 35 g / m ² , preferably 22 to 32 g / m ² and even more preferably 23 to 29 g / m ² , based on the surface of the composite panel.

The decorative sheets coated with the particles having a Mohs hardness of at least 8 and impregnated with a suitable binder can be used directly for the preparation of the structure described above. However, the decorative sheets coated with the particles may also first be subjected to drying to produce so-called pre-pregs.

To make the structure, individual sheets, preferably all sheets, of the various layers are preferably impregnated with a suitable binder.

According to a preferred embodiment, the structure comprises a plurality of kraft paper sheets, preferably three to six kraft paper sheets. On the top kraft paper sheet a decorative paper sheet is arranged. On this decorative paper sheet, as described above, the particles having a Mohs hardness of at least 8 may be applied. If an overlay layer is provided, then the particles are not applied to the decorative paper sheet but to the overlay sheet. In this case, the particle-coated overlay sheet is arranged on the decorative paper sheet.

According to a further preferred embodiment, in which no overlay sheet is provided, the decorative paper sheet applied to the uppermost kraft paper sheet is a pre-preg of decorative paper, a suitable binder and particles with a Mohs hardness of at least 8 arranged on the surface of the decorative paper.

According to yet another preferred embodiment, in which an overlay layer is provided, the overlay sheet applied to the decorative paper sheet covering the kraft paper sheets is a pre-preg of overlay sheets, a suitable binder and particles having a Mohs hardness of at least 8 arranged on the surface of the overlay sheet ,

According to yet another preferred embodiment for a structure for producing a composite panel according to the invention, which contains an overlay layer, an overlay sheet is first pre-impregnated with melamine-formaldehyde resin. For this preimpregnation 40 to 60 weight percent, more preferably 50 to 55 weight percent, of the intended amount for the impregnation of the overlay sheet amount of binder, preferably a melamine-formaldehyde resin is preferably used. Subsequently, a suspension containing the particles to be applied with a Mohs hardness of at least 8 and the remainder of the intended for the impregnation of the overlay sheet melamine-formaldehyde resin (preferably so 60 to 40 weight percent, more preferably 50 to 45 weight percent of for the impregnation of the overlay sheet provided amount of binder, preferably a melamine-formaldehyde resin), applied to the overlay sheet. This particle-coated overlay sheet is applied to the melamine-formaldehyde resin-impregnated decal sheet such that the particles having a Mohs hardness of at least 8 are on the outside of the overlay sheet, and therefore are not in contact with the decal sheet. The corresponding structure of decal sheet, overlay sheets and particles is finally applied to the top of the kraft paper sheets impregnated with a suitable binder, preferably a phenol-formaldehyde resin, in such a way that the decal sheet is in contact with a kraft paper sheet.

According to the invention, it is essential that the particles are arranged on the outside of the uppermost decoration sheet or of the uppermost overlay sheet.

According to a further preferred embodiment, the kraft paper sheets present in the structure are preferably impregnated with a phenol-formaldehyde resin. Of the

Binder content of the impregnated kraft paper sheet is preferably in the range of 25 to 40 weight percent, more preferably in the range of 28 to 36 weight percent and even more preferably in the range of 30 to 34 weight percent. The decorative paper sheet present in the structure is preferably impregnated with a melamine-formaldehyde resin or a melamine-urea-formaldehyde resin. The binder content of the impregnated decal sheet depends inter alia on the motif of the decal sheet. For plain colors, the binder content of the impregnated decal sheet is preferably in the range of 35 to 65 weight percent, more preferably in the range of 42 to 60 weight percent, and even more preferably in the range of 48 to 55 weight percent. For multicolor patterned or otherwise printed decor motifs, the binder content of the impregnated decal sheet is preferably in the range of 35 to 65 weight percent, more preferably in the range of 37 to 50 weight percent and even more preferably in the range of 40 to 45 weight percent. The binder content of the optional overlay sheet is preferably in the range of 60 to 90 weight percent, more preferably in the range of 65 to 86 weight percent, and even more preferably in the range of 70 to 83 weight percent.

An inventively prepared structure is then introduced and pressed between two press plates. For pressing, it is preferable to use press plates having a smooth, high gloss and abrasion resistant surface coated with titanium diboride, zirconium diboride, hafnium diboride, molybdenum diboride, tantalum boride, tungsten diboride or vanadium diboride. The coating with this diboride is preferably carried out in a magnetron sputter coating system and preferably has a Vickers hardness of at least 2000. Press plates have proven to be particularly suitable, as in the EP 0 826 790 are disclosed.

The compression of the structure is preferably carried out at a temperature in the range of 110 to 140 ° C, more preferably in the range of 120 ° C to 150 ° C and at elevated pressure of preferably at least 4 N / mm ² , more preferably at least 5 N / mm ² . The pressing time is preferably in the range of 40 to 90 minutes, more preferably in the range of 50 to 80 minutes.

The simultaneous application of heat and high pressure allows the flow and subsequent curing of the binder.

The product obtained after the compression of the construction and the curing of the resins is finally referred to as a composite panel.

The finished composite panel has, depending on the chosen structure, different thicknesses. Typical thicknesses are in the range of 0.5 mm to 2 mm, preferably in the range of 0.6 to 1.5 mm and particularly preferably in the range of 0.8 to 1.2 mm. However, it is also possible to produce composite panels with much larger thicknesses, such as in the range of 2 mm to 20 mm.

If the composite panel contains an overlay layer, then its thickness is preferably in the range from 80 to 120 μm, particularly preferably in the range from 80 to 110 μm. Therein, the thickness of the overlay layer is understood as meaning the distance between the outer side facing away from the decorative layer and the binder layer containing the particles having a Mohs hardness of at least 8 and the outer side of the decorative paper sheet in contact with the overlay layer. The thickness of the decorative layer is preferably in the range of 65 to 140 microns, more preferably in the range of 65 to 80 microns. Therein, the thickness of the decorative layer is understood to be the distance between the outside of the decorative paper sheet which is in contact with the overlay layer and the outside of the kraft paper sheet of the core layer which is in contact with the decorative layer. The thickness of the core layer can vary greatly depending on the desired thickness of the composite panel and is preferably in the range of 250 to 1900 microns, more preferably in the range of 500 to 1500 microns.

If the composite panel does not contain an overlay layer, then the thickness of the decorative layer is likewise preferably in the range from 65 to 140 μm, particularly preferably in the range from 80 to 140 μm. The thickness of the decorative layer is defined in this case as the distance between the outer layer facing away from the core layer of the binder layer containing the particles having a Mohs hardness of at least 8 and the outside of the with the Decorative layer in contact kraft paper sheet of the core layer. The thickness of the core layer can be, for example, in the range from 250 to 1900 .mu.m, particularly preferably in the range from 500 to 1500 .mu.m, independently of the presence of an overlay layer.

The final weight of the composite panel according to the invention depends on several factors, such as the thickness of the composite panel, the weight of the components used and the number of sheets used. Preferably, the weight of the composite panel is in the range of 1.2 to 1.6 kg per m ² surface area of the composite panel (kg / m ² ), more preferably in the range of 1.3 to 1.5 kg / m ² , for example 1.4 kg / m ² .

The surface of the composite panel formed by the binder layer containing the particles having a Mohs hardness of at least 8 has a gloss reduction GR _X and GRS _X after abrasion in the gloss level reduction test, which does not exceed a maximum value.

According to the invention, the degree of gloss is measured before and after a defined abrasion stress in order to determine the degree of gloss reduction. The test for determining the degree of gloss reduction is designated according to the invention as gloss level reduction test.

The determination of the gloss level is always within the scope of the invention according to DIN 67530 at a light incidence angle of 60 °. The obtained reflectometer values at 60 ° light incidence (measurement geometry) are related to a black, polished glass standard with a defined refractive index. For this standard, the reading is calibrated to 100 gloss units (100 GE).

By definition, the original degree of gloss is understood to mean that degree of gloss of the surface of the composite panel which is obtained before the abrasion stress in the degree of gloss reduction test. This initial gloss level is at least 80 GE, preferably at least 85 GE and more preferably 90 GE.

The abrasion under the gloss level reduction test is carried out as follows:

A carriage, on the underside of which a defined abrasive is applied, is guided along the surface of the composite panel with a uniform linear motion under a weight load of 0.5 N / cm ² over a distance of 220 mm. The linear movement is subsequently repeated in the direction of movement opposite to the first direction of movement. By definition, a double stroke is understood to mean a completely closed movement in one direction and in the opposite direction to that direction, so that the carriage covers the same distance twice in a double stroke (reciprocation). In the gloss level reduction test, the abrasion is performed by performing a defined number of double strokes, whereby the contact area coming into contact with the abrasive medium on the surface of the composite is determined by the first double stroke and remains the same throughout the abrasion stress.

By definition, to determine the degree of gloss reduction GR _X (or GRS _X ) after abrasion in the gloss level reduction test, the difference between the original gloss level and the gloss level after abrasion in the X double rub gloss reduction test is determined and the ratio between this difference and the original gloss level calculated. The value obtained is multiplied by 100 percent and referred to as the degree of gloss reduction after abrasion in the gloss level reduction test, GR _X (or GRS _X ). The following formula can therefore be used to calculate this value: $$\mathrm{Gloss\; reduction}\mathrm{.}{\mathrm{GR}}_{\mathrm{x}}\left(\mathrm{respectively}\mathrm{,}{\mathrm{GRS}}_{\mathrm{X}}\right)\left[\mathrm{in}\mathrm{\%}\right]\mathrm{=}\left\{\left[\left(\mathrm{original\; gloss\; level}\right)\mathrm{-}\left(\mathrm{Gloss\; level\; nack\; scrubbing\; with\; x\; double\; strokes}\right)\right]\mathrm{/}\left[\left(\mathrm{original\; gloss\; level}\right)\right]\right\}\mathrm{x}\mathrm{100}\mathrm{\%}$$

According to the invention, the abrasion in the gloss level reduction test to determine the gloss loss GR _X by using a sandpaper from Type P 1200 as abrasive. The term "P 1200" refers to the designation of the body in accordance with the international standard ISO 6344-1: 1999. Accordingly, the corundum particles have a d _s0 value of max. 58 μm, a d _s3 value of max. 29.7 μm, a mean particle size (d _s50 value) of 15.3 ± 1.0 μm and a d _s95 value of min. 10.2 μm, measured with the US sedimentometer according to ISO 8486-2. The corundum content of the abrasive paper used is 24.3 g / m ² . The weight of the abrasive paper used is 250 g / m ² .

According to the invention 500 double rubs are performed for determining the degree of gloss loss after GR _X shearing load in the degree of gloss reduction test. The value obtained for the degree of gloss reduction is accordingly referred to as "GR ₅₀₀ ".

The surface of the composite panel formed by the binder layer containing the particles having a Mohs hardness of at least 8 has a gloss reduction GR ₅₀₀ after abrasion in the gloss reduction test of at most 7%, preferably at most 6%, more preferably at most 5%, and still more preferably at most 4%.

A gloss reduction GR _X after abrasion in the gloss level reduction test can also be measured with a different number of double strokes. Thus, for example, 250 double strokes can be carried out for abrasion. The thus determined value for the gloss reduction is also referred to as GR ₂₅₀ .

The surface of the composite panel formed by the binder layer containing the particles having a Mohs hardness of at least 8 preferably has a rubbing degree reduction after abrasion in 250 double rubs gloss level reduction test, GR ₂₅₀ , of at most 5%, more preferably not more than 4%, more preferably not exceeding 3%, and in particular not exceeding 2%.

The abrasive medium used for the abrasive stress in the gloss level reduction test may also be steel wool. In the Steel wool is grade 1 steel wool, which consists of rectangular chips made from a material that complies with DIN 17145 of type 11Mn4Si with the material number 1.0492.

If steel wool is used as the sanding medium for the abrasive load in the gloss reduction test, then the gloss reduction is expressed in terms of GRS _X , whereby the index "X" following the abbreviation "GRS" again refers to the number of double strokes during grinding.

When steel wool is used as the abrasion abrasive grinding medium in the gloss level reduction test, the abrasive stress is preferably carried out by performing 500 double strokes. The value obtained for gloss level reduction is accordingly designated GRS ₅₀₀ .

Preferably, the surface formed by the binder layer containing the particles having a Mohs hardness of at least 8 has a GRS ₅₀₀ gloss level reduction after abrasion in the steel wool gloss reduction reduction test of at most 10%, preferably at most 7%, more preferably at most 5%, even more preferably at most 3% and in particular at most 1%.

An abrasion stress in the gloss level reduction test using steel wool can also be performed by applying 250 double strokes. The corresponding value obtained for gloss level reduction is consequently referred to as GRS ₂₅₀ .

Preferably, the surface formed by the binder layer containing the particles having a Mohs hardness of at least 8 has a gloss reduction GRS ₂₅₀ after abrasion in the steel wool gloss reduction reduction test of at most 5%, preferably at most 4%, more preferably at most 3%, even more preferably at most 2% and in particular at most 1%.

According to a preferred embodiment, the surface of the composite panel formed by the binder layer containing the particles having a Mohs hardness of at least 8 has an abrasion resistance according to DIN EN 13329, Annex E, which permits the classification of the composite panel into the abrasion class AC3. preferably AC4 and in particular AC5 allowed.

Accordingly, the abrasion resistance according to the test carried out according to DIN EN 13329, Annex E, preferably at an IP value (initial point) of at least 5000 revolutions, more preferably at least 5700 revolutions, most preferably at least 6500 revolutions. A preferred range is an IP value of 5,000 to 10,000 revolutions, more preferably 6,000 to 9,500 revolutions, and most preferably 6,500 to 9,000 revolutions. According to this test, the abrasion behavior of the composite panel is tested. For this purpose, a sample part of the composite plate rotates under two Abriebrädern which are provided with emery paper. Scrubbing measures the abrasion resistance of the composite panel. Rotary speed, type and change of the abrasive paper are exactly prescribed. The unit of measurement is the IP value, ie the number of revolutions after which the signs of wear occur. For the determination of the abrasion resistance, an emery paper defined in DIN EN 13329 is used which is characterized in particular by a basis weight of 70 g / m ² to 100 g / m ² and is open-coated with 180 grit of alumina having a grain size which is determined by a Sieve with openings of 100 microns fits, but not through openings of 63 microns.

According to a further preferred embodiment, the surface of the composite panel formed by the binder layer containing the particles having a Mohs hardness of at least 8 has impact resistance in accordance with the standard EN 13329, Annex F, which allows the composite panel to be classified into the Class IC2, preferably IC3, allowed. When performing the impact stress test using the large ball (diameter = 42.8 mm, mass = 324 g) as defined in this standard, the drop height is preferably at least 1300 mm, more preferably at least 1500 mm and especially at least 1700 mm. When performing the impact test defined in this standard using the small stress test The impact resistance is preferably in the range of 15 to 25 N, more preferably in the range of 17 to 23 N, and in particular in the range of 18 to 22 N.

In another aspect, the invention relates to a panel comprising a support and a composite panel adhered to the support of the invention. Preferably, the panel is a floor panel (floor panel). Furthermore, the panel may also be another plate, such as a table top.

Preferred supports are chipboard, plywood, support plates (optionally coated with laminate), high density fiberboard, medium density fiberboard, hardboard, blockboard, veneer, solid wood, honeycomb, foam, metal plates, sheets, mineral substrates, natural and artificial stone, tiles and plasterboard. The supports may be coated with a suitable binder, such as a melamine resin, or uncoated. The composite panel can be applied to both liquid-absorbent (absorbent) substrates, such as uncoated particle board and uncoated wood, and non-liquid-absorbent (non-absorbent) substrates, such as metals, ceramics, glass, coated woods, coated chipboard, etc.

Methods and means for firmly joining composite panel and support are known in the art. For example, the fixed connection of composite panel and carrier can be done by gluing or by means of known from the prior art fasteners. The bonding of the composite plate to the substrate material is performed such that the surface of the composite plate opposite to the surface containing the particles having a Mohs hardness of at least 8 is in contact with a surface of the substrate. Preferably, therefore, a surface of the carrier and a surface formed by the core layer of the composite plate are in contact in the panel.

The panel may also include other functional materials known in the art. By way of example, materials for flame protection, for shielding radiation, for sound damping, for stabilization and for moisture barrier may be mentioned.

Preferred functional materials include a back-pull and / or impact sound damping, as they are preferably used in floor panels.

The thickness of the panel is not limited. It is preferably in the range of 9 to 15 mm, more preferably in the range of 10 to 14 mm and most preferably in the range of 11 to 13 mm. The thickness of the composite panel present in the panel may, as described above, preferably in the range of 0.5 to 2 mm, more preferably in the range of 0.6 to 1.5 mm, and most preferably in the range of 0.8 to 1 , 2 mm lie. The thickness of the support, for example a high-density fiberboard, is preferably in the range of 5 to 13 mm, more preferably in the range of 8 to 10 mm, most preferably in the range of 9.0 to 9.6 mm. The optionally provided counter-pull and / or the impact sound damping preferably have a thickness in the range of 0.5 to 3 mm, particularly preferably in the range of 1 to 2 mm.

The final weight of the panel is not particularly limited. It is preferably in the range of 8 to 13 kg per m ² surface of the panel (kg / m ² ), more preferably in the range of 9 to 12 kg / m ² and most preferably in the range of 10 to 11 kg / m ² _.

The panel according to the invention can be processed in a manner which is obvious to a person skilled in the art. If the panel is a bottom plate, then this can be provided with a tongue and groove structure to allow the surface-connecting a plurality of such floor panels for the production of board-like or tile-like structures.

The present invention will be illustrated by the following examples, which are not to be construed as limiting:

Examples: Embodiment: Exemplary embodiment 1.1: Preparation of a corundum-containing melamine resin mixture

820 g of a 56% aqueous melamine impregnating resin solution (including hardener, wetting agent and separating agent) were mixed with 180 g of macro-precious corundum (type ZWSK 220, average particle size 68 μm).

Exemplary embodiment 1.2: Production of an impregnated and unilaterally coated overlay paper

An overlay paper made of α-cellulose having a basis weight of 30 g / m ² was soaked to saturation with melamine resin. The excess resin was removed on the surface between two polished steel rolls. The melamine resin applied to the overlay paper was allowed to dry for 2 hours at room temperature to obtain a preimpregnated overlay paper.

Subsequently, 135 g / m ^{2 of} the corundum-containing melamine resin mixture from Example 1.1 were evenly distributed on one side of the prepreg overlay paper. The now coated with corundum particles overlay paper was dried in a convection oven for 4 min at 125 ° C.

Example 1.3: Production of a composite panel according to the invention

To produce a composite panel according to the invention, a structure suitable for pressing with two press plates was first produced.

For this purpose, four sheets of kraft paper impregnated with a phenolic resin were placed on both sides of a 30 μm-thick sheet of a polypropylene release sheet. On the top kraft paper sheet was each a decorative paper sheet and on the Decorative paper sheet each applied a sheet of the prepared in Example 1.3, coated with corundum particles overlay paper. The overlay paper was placed on the decal sheet so that the surface of the overlay paper having the corundum particles was not in contact with the kraft paper sheet but directed outward. Such a structure is shown in Scheme 1.

The thus prepared structure was placed between two press plates with smooth, coated with titanium diboride in the magnetron sputter coating system, high gloss surfaces, pressed at a pressure of 10 N / mm ² and a maximum temperature of 135 ° C for 35 min and then cooled to room temperature ,

The obtained composite plate showed high gloss and high transparency and showed no traces of corundum coating and no fogging.

The measurement of the abrasion resistance of the surface of the composite panel formed by the binder layer arranged on the overlay layer, measured according to DIN EN 13329, Annex E, gave an IP value of 8100 revolutions.

Comparative Example 1

For comparison purposes, another composite panel was made, which does not fall under the present invention.

For this purpose too, a structure suitable for pressing with two press plates was first produced. For this purpose, four sheets of Kraft paper impregnated with a phenolic resin were placed on both sides of a 30 μm-thick sheet of a polypropylene release sheet. Each time a sheet of decorative paper was placed on the uppermost sheet of kraft paper and one sheet of Mead-822 overlay paper (in accordance with the US 3798111 ) applied. In this overlay paper corundum particles are not distributed on the surface or surfaces of the paper consisting of α-cellulose, but are distributed in the fiber layer.

The thus prepared structure was placed between two press plates with smooth, coated with titanium diboride in the magnetron sputter coating system, high gloss surfaces, pressed at a pressure of 10 N / mm ² at a maximum temperature of 135 ° C for 35 min and then cooled to room temperature ,

Comparative Example 2:

In order to produce a further composite panel for comparison purposes, which is not included in the present invention, a structure suitable for pressing with two press plates was also first prepared.

For this purpose, four sheets of kraft paper impregnated with a phenolic resin were placed on both sides of a 30 μm-thick sheet of a polypropylene release sheet. A decorative paper sheet was applied to the uppermost kraft paper sheet and a sheet of non-corundum coated overlay paper was applied to the decorative paper sheet.

The thus prepared structure was placed between two press plates with smooth, coated with titanium diboride in the magnetron sputter coating system, high gloss surfaces, pressed at a pressure of 10 N / mm ² at a maximum temperature of 135 ° C for 35 min and then cooled to room temperature ,

Results:

The surface of the composite sheets obtained by the binder layer disposed on the overlay layer of the composite sheets obtained in the embodiment and Comparative Examples 1 and 2 was subjected to abrasion abrasion with abrasive paper in the gloss reduction test. After the specified number of double strokes, the gloss level was measured at a light incidence angle of 60 ° according to DIN 67530. The values obtained are shown in Table 1: <b> Table 1: Degree of gloss at 60 ° after the specified number of double strokes. </ b> Gloss level in GE: exemplary embodiment Gloss level in GE: Comparative Example Gloss level in GE: Comparative Example double strokes 1 2 0 109.2 103.6 115.5 50 110.4 90.5 63.2 100 109.3 92.8 63.2 250 107.5 93.3 69.3 500 105.2 93.8 64.6

From the values determined, the original degree of gloss and gloss reductions GR ₂₅₀ and GR _{500 were} determined (see Table 2). <b> Table 2: Original gloss and gloss reductions GR <sub> 250 </ sub> and GR <sub> 500 </ sub> in the gloss reduction test after abrasion with abrasive paper. </ b> embodiment Comparative example Comparative example double strokes 1 2 Original gloss level [GE] 109.2 103.6 115.5 GR ₂₅₀ 1.6% 9.9% 40.0% GR ₅₀₀ 3.7% 9.5% 44.1%

Further, the surface formed by the binder layer disposed on the overlay layer of the composite plates obtained in the embodiment and Comparative Examples 1 and 2 in the gloss reduction test was subjected to abrasion with steel wool. After the specified number of double strokes, the gloss level was measured at a light incidence angle of 60 ° according to DIN 67530. The values obtained are shown in Table 3: <b> Table 3: Gloss level at 60 ° after the specified number of double strokes. </ b> Gloss level in GE: exemplary embodiment Gloss level in GE: Comparative Example Gloss level in GE: Comparative Example double strokes 1 2 0 114.2 102.8 118.2 50 114.6 99.2 115.7 100 114.2 92.5 111.9 250 114.2 89.9 101.3 500 114.3 80.5 88.6

From the values determined, the original degree of gloss and the gloss reductions GRS ₂₅₀ and GRS _{500 were} determined (see Table 4). <b> Table 4: Original gloss and gloss reductions GRS <sub> 250 </ sub> and GRS <sub> 500 </ sub> in the gloss reduction test after abrasion with steel wool. </ b> embodiment Comparative example Comparative example double strokes 1 2 Original gloss level [GE] 114.2 102.8 118.2 GR ₂₅₀ 0.0% 12.5% 14.3% GR ₅₀₀ 0.0% 21.7% 25.0%

Although numerous measures are known in the prior art to increase the abrasion resistance or gloss retention of the surface of composite panels, none of these measures resulted in a composite panel having a surface that exhibits both superior abrasion resistance and superior gloss retention.

Comparative experiment with respect to EP 0 219 769 B1 and AT 40 807 E:

The EP 0 219 769 B1 and AT 40 807 E have studied the resistance of the laminate surface to scratching. In each case, the gloss loss of the laminate surface was measured by abrasion in two places. The scrubbing was done by rubbing with 10 double strokes, using a Crockmeter apparatus, using 3M Scotch Brite type 8A abrasive pads. The investigations showed a gloss loss of 4% and 5%, respectively.

Attempts were made to reduce the gloss of the composite panel according to the invention under the experimental conditions, as in EP 0 219 769 B1 respectively. AT 40 807 E described, performed. Table 5: Degree of gloss reduction of the composite panel according to the invention in gloss level reduction test according to EP 0 219 769 B1 and AT 40 807 E by abrasion with 10 double strokes using 3 M Scotch Brite type 8A abrasive pads. </ b> Gloss reduction degree Sample 1 Sample 2 Sample 3 10 double strokes 1.8% 1.3% 1.5%

The average degree of gloss loss of the composite panel according to the invention according to the test method according to EP 0 219 769 B1 respectively. AT 40 807 E is 1.5%.

The composite panel according to the invention has a very low gloss loss of only 1.5% and thus a much lower degree of gloss reduction than the composite panels, which in EP 0 219 769 B1 respectively. AT 40 807 E are disclosed.

The outstanding properties are inventively by the choice of the size of the particles having a Mohs hardness of at least 8, the amount of particles having a Mohs hardness of at least 8, and the particular arrangement of the particles having a Mohs hardness of at least 8 at the Surface of the composite panel reached. This is particularly noteworthy because in the prior art to achieve these properties partly contrary measures have been proposed.

Claims (9)

1. Composite board, comprising

   a) a core layer, containing one or more sheets of kraft paper,

   b) a decorative layer, comprising a sheet of decorative paper,

   c) particles having a Mohs hardness of at least 8,

   d) a binder arrangement containing at least one binder in the cured state, the core layer and the decorative layer being provided in the binder arrangement and there being on the decorative layer a cured binder layer which contains the particles having a Mohs hardness of at least 8,
   the level of gloss of the composite board being at least 80 gloss units (GE), and

   (i) the surface of the composite board, formed by the binder layer, exhibiting a reduction in the level of gloss after abrasion stress in the gloss reduction test GR₅₀₀ of at most 7%, the original level of gloss being at least 80 GE,

   (ii) the particles having an average grain size in the range from 5 - 100 µm, and

   (iii) the loading of the composite board with the particles lying in the range from 21 - 35 g/m², based on the surface area of the composite board,

   the determination of the level of gloss always being carried out in accordance with DIN 67530 with a light incidence angle of 60°.
2. Composite board, comprising

   a) a core layer, containing one or more sheets of kraft paper,

   b) a decorative layer, comprising a sheet of decorative paper,

   b1) an overlay layer, comprising one or more sheets of a preferably fibre-containing material,

   c) particles having a Mohs hardness of at least 8,

   d) a binder arrangement containing at least one binder in the cured state, the core layer, the decorative layer and the overlay layer being provided in the binder arrangement and there being on the overlay layer a cured binder layer which contains the particles having a Mohs hardness of at least 8,
   the level of gloss of the composite board being at least 80 gloss units (GE), and

   (i) the surface of the composite board, formed by the binder layer, exhibiting a reduction in the level of gloss after abrasion stress in the gloss reduction test GR₅₀₀ of at most 7%, the original level of gloss being at least 80 GE,

   (ii) the particles having an average grain size in the range from 5 - 100 µm, and

   (iii) the loading of the composite board with the particles lying in the range from 21 - 35 g/m², based on the surface area of the composite board,

   the determination of the level of gloss always being carried out in accordance with DIN 67530 with a light incidence angle of 60°.
3. Composite board according to Claim 1 or 2, the surface of the composite board formed by the binder layer exhibiting a reduction in the level of gloss after abrasion stress in the gloss reduction test GRS₅₀₀ of at most 10%.
4. Composite board according to one of the preceding claims, the surface of the composite board formed by the binder layer exhibiting an abrasion resistance to DIN EN 13329, Annex E, expressed as an IP value, of at least 5000 revolutions.
5. Composite board according to one of the preceding claims, the particles having a Mohs hardness of at least 8 being corundum particles.
6. Composite board according to Claim 5, the average grain size of the corundum particles lying in the range from 45 - 75 µm.
7. Composite board according to one of the preceding claims, the loading of the composite board with the particles lying in the range from 23 to 29 g/m², based on the surface area of the composite board.
8. Panel comprising a composite board according to one of the preceding claims.
9. Panel according to Claim 8 in the form of a floorboard.