Method to produce a building panel and a semi finished product
A method to produce a building panel, including: providing a substrate, applying a thermosetting binder in dry form on the substrate for forming a sub-layer, applying a sheet on the sub-layer, and pressing the substrate, the sub-layer and the sheet together to form a building panel, thereby the thermosetting binder of the sub-layer impregnates the sheet from below. Also, a semi-finished product.
1. A method to produce a building panel, comprising
providing a substrate,
applying a thermosetting binder in dry form on the substrate for forming a sub-layer, wherein the sub-layer comprises at least 90 wt % of the thermosetting binder and is free of moisture-absorbing fillers,
controlling the moisture content of the sub-layer when arranged on the substrate such that the moisture content is 15-35 wt %,
applying a sheet on the sub-layer, wherein the sheet comprises one or more of a a non-woven, a woven fibre or a non-woven fibre sheet, or a fibre sheet, wherein the sheet being applied on the sub-layer is unimpregnated, and
pressing the substrate, the sub-layer and the sheet together to form a building panel, thereby the thermosetting binder of the sub-layer impregnates the sheet, wherein the sheet forms a surface of the building panel.
2. The method according to claim 1 , wherein controlling the moisture content of the sub-layer comprises one or more of the following:
applying steam on the substrate prior to applying the sub-layer,
applying steam on the sub-layer when arranged on the substrate,
applying steam on the sheet,
applying liquid on the substrate prior to applying the sub-layer,
applying liquid on the sub-layer when arranged on the substrate,
applying liquid on the sheet, and/or
drying the sub-layer and/or the sheet.
3. The method according to claim 1 , wherein the sub-layer consists essentially of the thermosetting binder.
4. The method according to claim 1 , further comprising printing a décor on the sheet when arranged on the sub-layer.
5. The method according to claim 4 , wherein the sheet is adhered to the sub-layer prior to printing.
6. A method to produce a building panel, comprising
providing a substrate,
controlling relative humidity (RH) of ambient air enclosing an application device adapted to apply a thermosetting binder in dry form,
applying a thermosetting binder in dry form on the substrate by said application device for forming a sub-layer,
controlling the moisture content of the sub-layer when arranged on the substrate such that the moisture content is 15-35 wt %,
applying a sheet on the sub-layer, wherein the sheet being applied on the sub-layer is a non-woven, a woven fibre or a non-woven fibre sheet, wherein the sheet is unimpregnated, and
pressing the substrate, the sub-layer and the sheet together to form a building panel, thereby the thermosetting binder of the sub-layer impregnates the sheet, wherein the sheet forms a surface of the building panel.
7. The method according to claim 6 , wherein the relative humidity (RH) is 35-60% RH.
8. The method according to claim 6 , wherein the sheet comprises one or more of a a non-woven, a woven fibre or a non-woven fibre sheet.
9. The method according to claim 6 , wherein the sub-layer consists essentially of the thermosetting binder.
10. The method according to claim 6 , further comprising printing a décor on the sheet when arranged on the sub-layer.
11. The method according to claim 10 , wherein the sheet is adhered to the sub-layer prior to printing.
12. The method according to claim 6 , further comprising applying moisture to the thermosetting binder, the sub-layer, the sheet, and/or the substrate prior to pressing.
13. A method to produce a building panel, comprising
providing a substrate,
applying at least one thermosetting binder on the substrate,
controlling reactivity of said at least one thermosetting binder by applying different types and/or forms of thermosetting binders on the substrate to form a sub-layer, wherein the sub-layer is free of moisture-absorbing fillers and possesses a moisture content of 15-35 wt %,
applying a sheet on said sub-layer, wherein the sheet comprises one or more of a paper sheet, a non-woven, a woven fibre sheet, or a fibre sheet, wherein the sheet being applied is unimpregnated, and
pressing the substrate, sub-layer and the sheet together to form a building panel, thereby said at least one thermosetting binder impregnates the sheet, wherein the sheet forms a surface of the building panel.
14. The method according to claim 13 , wherein controlling reactivity of said at least one thermosetting binder comprises applying a first thermosetting binder in liquid form and applying a second thermosetting binder in powder form on the first thermosetting binder.
15. A method to produce a building panel, comprising
providing a substrate,
applying a thermosetting binder in dry form on the substrate for forming a sub-layer,
applying a sheet on the sub-layer, wherein the sheet comprises one or more of a a non-woven, a woven fibre or a non-woven fibre sheet, or a fibre sheet, wherein the sheet being applied on the sub-layer is unimpregnated, and
pressing the substrate, the sub-layer and the sheet together to form a building panel, thereby the thermosetting binder of the sub-layer impregnates the sheet,
wherein a moisture content of the sub-layer when arranged on the substrate is 15-35 wt %,
wherein the sub-layer comprises at least 90 wt % of the thermosetting binder and is free of moisture-absorbing fillers, and
wherein the sheet forms a surface of the building panel.
16. The method according to claim 15 , wherein the sub-layer consists essentially of the thermosetting binder.
17. The method according to claim 15 , wherein the sub-layer comprises the thermosetting binder and non-absorbing fillers.
18. The method according to claim 15 , further comprising applying moisture to the thermosetting binder, the sub-layer, the sheet, and/or the substrate prior to pressing.
19. The method according to claim 15 , further comprising printing a décor on the sheet when arranged on the sub-layer.
20. The method according to claim 19 , wherein the sheet is adhered to the sub-layer prior to printing.
21. A semi-finished product adapted to form, or form part of, a building panel, comprising
a substrate,
a sub-layer arranged on the substrate, the sub-layer formed of a thermosetting binder,
a sheet arranged on the sub-layer, wherein the sheet comprises one or more of a a non-woven, a woven fibre or a non-woven fibre sheet,
wherein the moisture content of the sub-layer is 15-35 wt %, such that the sheet is adhered to the sub-layer,
wherein the sub-layer is free of moisture-absorbing fillers, and
wherein an upper side of the sheet facing away from the sub-layer is substantially unimpregnated by thermosetting binder.
22. The method according to claim 21 , wherein the sub-layer comprises non-absorbing fillers.
23. The semi-finished product according to claim 21 , wherein the thermosetting binder is a B-stage thermosetting binder.
24. The semi-finished product according to claim 21 , wherein the thermosetting binder is in A-stage and B-stage.
25. The semi-finished product according to claim 21 , wherein the sub-layer has impregnated less than half the thickness of the sheet.
26. The method according to claim 6 , wherein the sub-layer is free of moisture-absorbing fillers.
27. The method according to claim 13 , wherein the sub-layer is free of moisture-absorbing fillers.