Method for producing a material plate provided with a decorative layer

Abstract

Provided is a method for producing a wood based board including a support board and a decor paper disposed on the support board. The method includes the steps of a) providing a support board, b) applying at least one layer of at least one impregnating resin onto the at least one side of the support board, c) providing the decor paper, d) applying at least one resin as impregnating agent onto the side of the decor paper opposite from the decor, and e) placing the decor paper with the side impregnated opposite from the decor onto the side of the support board provided with the impregnating resin.

Claims

1. A method for producing a board of wood based material including a support board and a decor paper disposed on the support board, the method comprising the steps of: a) providing the decor paper, the decor paper having a decoration on a side thereof, b) applying at least one resin as an impregnating agent solely onto a side of the decor paper opposite from the decoration, wherein the amount of resin applied is between 30% and 70%, based on a paper weight of the decor paper, and wherein the impregnating agent used is a melamine-formaldehyde resin, a melamine-phenol-formaldehyde resin, a melamine-urea resin, a polyurethane resin or an acrylate resin having a solid content between 30% and 50%, c) providing the support board, d) applying at least one layer of impregnating resin to at least one side of the support board, and e) placing the side of the decor paper opposite from the decoration onto the at least one side of the support board provided with the at least one layer of the at least one impregnating resin, wherein the decor paper impregnated on the side opposite from the decor has a swelling in length in a range between 0.2% and 0.4% and a swelling in width in a range between 0.5% to 0.9%.

2. The method according to claim 1, wherein the decor paper impregnated on the side opposite from the decoration is dried to a moisture of 3-10 wt %.

3. The method according to claim 1, wherein the amount of liquid resin applied to the side of the decor paper opposite from the decoration is between 40 and 60% based on the paper weight of the decor paper.

4. The method according to claim 1, wherein the decor paper impregnated on the side opposite from the decor is rolled up before being placed onto the support board.

5. The method according to claim 1, wherein the decor paper impregnated on the side opposite from the decor is placed onto the support board immediately following the impregnation.

6. The method according to claim 1, wherein the impregnation agent applied to the decor paper comprises the solid content between 40% to 50%.

7. The method according to claim 1, wherein the impregnating resin applied to the at least one side of the support board is a melamine-formaldehyde-resin, melamine-phenol-formaldehyde resin, a melamine-urea resin, a polyurethane resin or an acrylate resin with a solid content between 55% to 80%.

8. The method according to claim 1, wherein following the placement of the decor paper onto the support board at least one further layer of a resin is applied.

9. The method according to claim 8, wherein the resin to be applied onto the decor paper further comprises natural and/or synthetic fibers, abrasion resistant particles and optionally further additives.

10. The method according to claim 8, wherein after an interim drying at least one further application of a mixture of liquid resin, natural and/or synthetic fibers, abrasion resistant particles and optionally further additives takes place or at least one overlay is applied.

11. The method according to claim 1, wherein after the placement of the decor paper impregnated on the side opposite from the decor onto the support board at least one resin impregnated overlay is applied.

12. The method according to claim 1, wherein at least one backing paper is applied to the opposite side of the support board, which is not provided with the decor paper.

13. The method according to claim 1, wherein the support board, the decor paper, and the impregnating resin are compressed.

14. The method according to claim 1, wherein the support board is made of a wood based material, a plastic material, or a mixture of wood based and plastic materials.

15. The method according to claim 2, wherein the decor paper impregnated on the side opposite from the decoration is dried to the moisture of 5-7%.

16. The method according to claim 2, wherein the decor paper impregnated on the side opposite from the decoration is dried to the moisture of 6 wt %.

17. The method according to claim 3, wherein the amount of liquid resin applied to the side of the decor paper opposite from the decoration is 50% based on the paper weight of the decor paper.

18. The method according to claim 6, wherein the impregnation agent applied to the decor paper comprises the solid content of 50%.

19. The method according to claim 7, wherein the impregnating resin applied to the at least one side of the support board comprises the solid content between 60% to 70%.

Description

DETAILED DESCRIPTION OF THE INVENTION

(1) The present invention is subsequently explained and described by means of multiple examples for a better understanding.

Example 1

(2) A print basis paper (paper weight 8 g/m.sup.2) is unrolled from an unrolling device and is printed in gravure printing and/or digital printing method and is then impregnated in an impregnating device on the backside with a melamine resin. Thereby, about 50 g melamine resins/m.sup.2 with a solid content of about 50% is applied.

(3) The paper is subsequently dried in a convection dryer or by NIR (Near Infrared) to a moisture of about 6 wt %.

(4) Subsequently, the impregnate is pressed in a continuous working press onto a board pre-coated with melamine resin (applied amount 50 g melamine resin/m.sup.2, solid content of impregnating resin 60 wt %). The melamine resin being on the board contains the usual additives (hardener, wetting agent, defoamer and so on) and was pre-dried after the application with the drum by convection or an IR.

(5) A mixture of melamine resin (solid content impregnating resin 60 wt %), cellulose and corundum in an amount of 50 to 80 g impregnating resins/m.sup.2 depending on the desired abrasion class is applied subsequently onto the decor paper also by drum application. The mixture is dried in a convection dryer or by near infrared.

(6) Subsequently, further resin applications (between 2 and 4) take place, whereby a mixture of melamine resin, cellulose and glass beads is applied. The solid content of the fleet is thereby also at about 60%. The drying is realized as described above.

(7) At the end of this process the coating is dried to a residual moisture of about 6 wt %. Subsequently, the coating is hardened in a short cycle press or in a continuously working press (p=30 bar, T=200° C.), whereby on the backside of the board either resin impregnated backing paper or a resin also applied in the liquid process and pre-dried is exposed on the backside of the board.

Example 2

(8) A decor paper (paper weight: 80 g/m.sup.2) is unrolled from an unroller device and is impregnated on the back side with an urea resin in an impregnating device. Thereby about 50 g urea resin/m.sup.2 are applied (solid content: 50 wt %).

(9) The paper is dried subsequently in a convection dryer or by NIR to a moisture of about 6%.

(10) Than the one-sided impregnated paper is pressed in a continues working press onto a board pre-coated with a melamine resin (applied amount 50 g melamine resin/m.sup.2, solid content 60 wt %). The melamine resin being on the board contains the usual additives (hardener, wetting agent, defoamer and so on) and was pre-dried after the application with a drum by convection or NIR.

(11) A mixture of melamine resin (solid content: 60 wt %), cellulose and corundum in an amount of 50-80 g impregnating resin/m.sup.2 pending on the desired abrasion class is applied onto the decor paper subsequently also by drum application. The mixture is dried in a convection dryer or by near infrared. The moisture of the coating is about 6 wt % after the drying process.

(12) Subsequently a resin impregnated protection overlay is placed (paper grammage: 25 g/m.sup.2, final weight 100 g/m.sup.2). Subsequently the coating is hardened in a short cycle press or in a continuous working press (p=30 bar, T=200° C.) whereby either a resin impregnated backing paper or a resin layer applied in a liquid process on the back side is, also hardened.

Example 3

(13) A complete resin impregnated decor paper (resin amount: 100 wt %) and resin impregnated overlay (paper weight 30 g/m.sup.2, final weight: 150 g/m.sup.2) is placed on a HDF board. Corundum as abrasion reducing means was in the resin formulation, which was used for impregnating the overlay. Recycling paper (paper weight 100 g/m.sup.2; resin amount 120 wt %) is used as backing paper. The complete structure is compressed in a short cycle press at 30 bar and 200° C.

Example 4

(14) A strand of HDF boards is coated continuously with an impregnating resin on the basis of melamine in drum application. 100 g melamine resin/m.sup.2 (solid content: 60 wt %) are thereby applied. The impregnating resin formulation contains the usual additives as hardener, wetting and separation means.

(15) The impregnating resin is pre-dried after the application by means of a convection dryer or an NIR in order to evaporate a part of the water. However, the drying process has only to be conducted to the point that the resin contains its stickiness or the possibility of penetration into a paper.

(16) A dry decor paper (paper weight: 80 g/m.sup.2) is unrolled from an unrolling device and is rolled into the resin still capable of flowing. Thereby it has to be guaranteed that no wrinkles or waviness arise in the paper by multiple drums arranged one after the other on the upper side.

(17) Than the paper is pressed in a continuous working press onto the board pre-coated with melamine resin. Subsequently a mixture of melamine resin (solid content impregnating resin: 60 wt %), cellulose and corundum in an amount of 50-80 g impregnating resin/m.sup.2 depending on the desired abrasion class is applied onto the decor paper also by drum application. The mixture is dried in a convection dryer or by near infrared. The moisture of the coating is about 6 wt % after the drying process.

(18) Subsequently a resin impregnated overlay (paper grammage: 25 g/m.sup.2, final weight: 100 g/m.sup.2) is placed thereon. Thereafter the coating is hardened in a short cycle press or in a continuous working press (p=30 bar, T=200° C.) wherein on the back side either a resin impregnated backing paper or a resin layer applied by a liquid method is hardened.

(19) The products of the examples 1 and 2, which were produced according to the method of the invention by using a partially impregnated decor paper, differ in respect to the product of the example 3, which was produced using a complete impregnated decor paper in that they have a significant better behavior regarding their storage time. A complete impregnated paper has to be processed within a few month. The partially impregnated papers are however still usable after one year.

(20) Furthermore, when processing from roll to roll or from the roll less cutting and material loss occurs.

(21) In respect to the product of example 4 produced with a dry decor paper it has to be noticed that a one-sided impregnation according to the invention can be significantly simpler carried out in an impregnation channel than the pressing of glue into the backside of a paper as in case of the dry décor paper. This is aggravated by the different parameter (density of the paper, pigment content and so on).

(22) Furthermore also significantly more time is provided for the impregnation process in comparison to the pressing in what leaves the process less critical.