Covering panel and process of producing covering panels

1. Covering panel, including a floor panel, wall panel or ceiling panel, said covering panel comprising at least one substrate and a top layer, whereby said substrate comprises a polyvinyl chloride and a filler material, wherein at least 95 wt. % of said filler material comprises a mixture of chalk and talc, wherein said substrate comprises said filler material in an amount from 30 to 50 wt. % based on the total weight of said substrate, wherein said substrate further comprises a void volume from 30 to 70 vol. % determined according to ISO 4590 and wherein the top layer is integrally attached to an upper surface of the substrate, wherein the mixture of chalk and talc has a chalk to talc ratio of 8:1 to 1:1.

2. Covering panel according to claim 1 , whereby said chalk is comprised of particles with at least 95% of said particles having a particle size less than 25.0 μm, measured according to ISO 13317-3.

3. Covering panel according to claim 1 , whereby said talc is comprised of particles with at least 95% of said particles having a particle size less than 100.0 μm, measured according to ISO 13317-3.

4. Covering panel according to claim 1 , wherein said substrate comprises one or more plasticizers in an amount of less than 10 wt. %, based on the total weight of said substrate.

5. Covering panel according to claim 1 , whereby any of said top layer and/or said substrate is substantially free of one or more plasticizers.

6. Covering panel according to claim 1 , whereby said substrate further comprises at least one impact modifier, preferably in an amount from 0.1 to 15 wt. % based on the total weight of said substrate.

7. Covering panel according to claim 6 , whereby said substrate further comprises stabilizers, processing aids, lubricants, colorants, foaming agents and/or adhesion promoters.

8. Process of producing covering panels including floor panels, wall panels or ceiling panels, each covering panel comprising a top layer and at least one substrate, whereby said at least one substrate comprises polyvinyl chloride and a filler material; the method comprising the steps of:

mixing the polyvinyl chloride and a filler material, thereby obtaining a mixture;

extrusion of said mixture, thereby obtaining a substrate;

optionally, laminating said substrate to a top layer;

thereby obtaining a covering panel, wherein said filler material is mixed with said polyvinyl chloride in an amount from 30 to 50 wt. % based on the total weight of said mixture, wherein at least 95 wt. % of said filler material comprises a mixture of chalk and talc,

wherein the mixture of chalk and talc has a chalk to talc ratio of 8:1 to 1:1,

wherein said substrate further comprises a void volume from 30 vol. % to 70 vol. % determined according to ISO 4590, and

wherein the top layer is integrally attached to an upper surface of the substrate.

9. Process according to claim 8 , whereby the surface of the extruded substrate is not subjected to a surface modification step prior to further processing.

10. Process according to claim 8 , whereby said substrate is attached to said top layer at a temperature higher than the softening point but lower than the melt temperature of the principal polymer comprised in said substrate.

11. Process according to claim 8 , whereby at least the surface of said substrate is reheated before attaching said substrate to said top layer.

12. Process according to claim 11 , whereby said substrate and said top layer are subsequently subjected to a double stack lamination process.

13. Covering panel according to claim 1 having an E-modulus of 1200 MPa or higher.

14. Covering panel according to claim 1 , wherein the top layer comprises a print layer and a wear layer.

15. Covering panel according to claim 14 , wherein the wear layer is a transparent polyvinyl chloride.

16. Covering panel according to claim 1 , wherein the void volume is from 45 vol. % to 60 vol. %.