WATERMARKED DECOR PAPER

Abstract

Watermarked Décor paper (11).

Claims

1. Watermarked Décor paper (11).

2. Paper according to claim 1, being watermarked over the entire surface thereof.

3. Paper according to claim 1, being watermarked over a part of the surface thereof.

4. Paper according to claim 1, comprising at least one inorganic or organic opacifying filler, providing opacity after lamination of the watermarked Décor paper.

5. Paper according to claim 4, the opacifying filler having a refractive index greater than 2.

6. Paper according to claim 5, the opacifying filler comprising or being titanium dioxide.

7. Paper according to claim 4, the opacifying filler providing opacity by absorbing light.

8. Paper according to claim 7, the opacifying filler comprising or being a pigment chosen from iron oxides.

9. Paper according to claim 7, the opacifying filler comprising or being an organic pigment.

10. Paper according to claim 4, the content of opacifying filler being greater than or equal to 10% relative to the total weight of the sheet.

11. Paper according to claim 10, the total amount of opacifying filler ranging from 3 to 50 g/m.sup.2.

12. Decorative laminate (10; 20) comprising a watermarked Décor paper (11) as defined in claim 1, the watermark being visible in reflection on the laminate.

13. Decorative laminate according to claim 12, having a colour contrast between the watermarked Décor paper and the underlying structure.

14. Decorative laminate according to claim 13, the underlying structure being a particle board (40), or one or more impregnated kraft paper sheets (12) or a contrast sheet (13).

15. Decorative laminate according to claim 12, the watermarked Décor paper (11) being unprinted.

16. Decorative laminate according to claim 12, having been obtained by a low pressure laminate (LPL), a high pressure laminate (HPL), or a continuous pressed laminate (CPL) process.

17. Process for producing a Décor paper according to claim 1, comprising producing the watermark (11a) in the wet part of the paper making machine using a Dandy roll (33).

18. Process for producing a Décor paper according to claim 1, comprising producing the watermark (11a) in the wet part of the paper making machine using a drainage fabric having a structure which makes it possible to obtain the desired watermark.

19. Process for producing a laminate, wherein a watermarked Décor paper according to claim 1 is impregnated with thermosetting resin.

20. Paper according to claim 11, the total amount of opacifying filler ranging from 15 to 40 g/m.sup.2.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0057] A better understanding of the invention will be gained by reading the detailed description that follows of an example of a non-limiting embodiment of it, and by examining the appended drawing, in which:

[0058] FIG. 1 is a partial and schematic cross section of an example of an HPL laminate according to the invention,

[0059] FIG. 2 is a partial and schematic cross section of an example of an LPL laminate according to the invention,

[0060] FIG. 3 shows the watermarked Décor paper according to the invention in isolation and schematically,

[0061] FIG. 4 shows a partial and schematic example of a paper machine for manufacturing watermarked Décor paper according to a process of the invention, and

[0062] FIG. 5 shows a detail in the production of a Dandy roll that can be used to implement the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0063] FIG. 1 shows an example of an HPL laminate 10 according to the invention. In this figure, and for the sake of clarity, the actual proportions are not respected.

[0064] Laminate 10 contains a Décor paper 11 in conformity with the invention, covering an underlying structure 15 composed, for example, of a possible contrast sheet 13 and of one or more sheets of kraft paper impregnated with melamine formaldehyde resin or urea or phenolic formol 12.

[0065] The sheet of Décor paper 11 may be covered with a protective sheet 14 called “overlay”.

[0066] The sheet of Décor paper 11 may be impregnated with resin.

[0067] The assembly 15 composed of the sheet of Décor paper 11, of one or more underlying layers 12 and possibly 13, and by any protective layer 14, is glued to a support such as a particle board 40.

[0068] FIG. 2 shows an example of an LPL laminate 20 according to the invention. In this figure, and for the sake of clarity, the actual proportions are not respected.

[0069] The laminate 20 is composed of a sheet of Décor paper 11 according to the invention, impregnated with resin. The assembly is laminated directly on the support 40.

[0070] The sheet of Décor paper 11 contains, in accordance with the invention, a watermark 11a shown schematically in FIG. 3.

[0071] This watermark 11a causes a variation in opacity within the sheet because of a local variation in the quantity of opacifying filler. Accordingly, the watermark 11a is formed by the opacifying filler and more particularly due to a local concentration variation of this opacifying filler in the sheet of Décor paper 11.

[0072] This variation in opacity is sufficiently pronounced for a corresponding pattern to be visible to the naked eye when the external side 16 of the laminate is observed.

[0073] In a general way, Décor paper is used to mask the sheets 12 composing the underlying structure or the particle board 40. Thus, there is a natural contrast between the Décor paper and the underlying structure or particle board 40, making the watermark 11a easily visible.

[0074] If the visibility of the watermark is to be increased still more, a contrast sheet 13 of a different colour from that of the Décor paper 11 will be used. The Décor paper 11 can thus be white and the contrast sheet 13 non-white. The Décor paper 11 may also be non-white, and of a different colour from the contrast sheet 13 or of any other underlying structure.

[0075] The protective sheet 14 is preferably transparent once it has been impregnated with resin not containing any opacifying filler.

[0076] The Décor paper 11 contains an opacifying filler whose distribution within the sheet is modified by creating the watermark 11a.

[0077] To manufacture the Décor paper 11, a paper machine such as the one shown schematically in FIG. 4 can be used.

[0078] This machine has a headbox 30 which feeds the fibrous suspension into the sheet forming section 31, where the mixture is drained.

[0079] The fibrous suspension is produced conventionally.

[0080] For Décor paper, the pulp used is typically based on short fibres, essentially or exclusively for example 100% short wood fibres, in particular eucalyptus. After the pulp has been refined, an opacifying filler is added, for example titanium dioxide (rutile) to develop the opacity, together with one or more coloured pigments to adjust the colour if necessary. The usual fixing additives and the wet strength agent can be added, for example a polyamine epichlorhydrin resin, a polyamide/polyamine-epichlorhydrin resin, a cationic polyacrylate or a cationic starch. This is the mixture that is sent to the headbox after dilution.

[0081] The sheet being formed 32 is driven by a forming fabric 36 which loops round and passes under a watermark roller 33, also called “Dandy roll”, which locally deforms the sheet and modifies the distribution of opacifying filler within the sheet to form the watermark 11a.

[0082] The sheet being formed 32 has a very high moisture content between 80% and 98% when it passes under the Dandy roll 33, the water line 34 being downstream of the Dandy roll 33 as illustrated.

[0083] One or more suction boxes 35 are placed downstream of the Dandy roll 33 to absorb part of the residual water from the sheet, then the sheet is fed to a part of the machine not shown here for pressing, drying and possibly calendering. The watermarked Décor paper can then be wound on reels.

[0084] The Dandy roll 33 has a relief surface to create the desired watermark 11a. The relief surface of the Dandy roll 33 enables to create a local concentration variation of the opacifying filler within the sheet of paper and therefore the watermark 11a.

[0085] This relief is for example obtained with a grid 36 over the entire surface of the Dandy roll 33 as illustrated in FIG. 5. In such embodiment, the pattern formed by the grid 36 corresponds to the desired watermark 11a that will be created on the Décor paper 11 and that will be visible on the laminate 20. As a variant, the relief is obtained by embossing a fabric positioned in place of the grid. The relief is preferably around the entire surface of the Dandy roll 33, continuously or in the form of spaced out patterns. According to this variant, the pattern formed by embossing the fabric corresponds to the desired watermark 11a. Thus, during the papermaking process, the emboss relief enables to create a local concentration variation of the opacifying filler during the drainage of the paper substrate containing the opacifying filler to form the Décor paper 11.

[0086] The watermarked Décor paper 11 is then used as such, in a known laminate manufacturing process preferably without being printed. Indeed, the printing of the watermarked Décor paper 11 is not necessary because of the presence of the watermark 11a formed on the Décor paper 11 due to the local concentration variation of the opacifying filler within the Décor paper 11.

[0087] During the manufacture of high pressure, low pressure or continuous laminates, the watermarked Décor paper 11 can be impregnated with a heat-stable thermosetting resin and hot pressed with its support at high or low pressure. The thermosetting resin can be chosen from melamine-formaldehyde resins, urea-formaldehyde resins, benzoguanamine-formaldehyde resins, unsaturated polyester resins, dicyanamide-formaldehyde resins, epoxy resins, polyurethane resins, acrylic resins and their mixtures.

[0088] Alternatively, in the case of a process without impregnation (dry process), the watermarked Décor paper is stacked, non-impregnated between two papers impregnated with thermosetting resin, and impregnation of the watermarked Décor paper occurs when pressure is exerted on the stack.

[0089] Once the resin has been completely cured after lamination, it will provide surface strength to the final laminate (abrasion resistance, dirt and steam resistance and resistance to chemicals such as solvents, acids and bases, etc.)

[0090] According to one particular embodiment of the invention, the watermarked Décor paper of the invention is impregnated with a thermosetting resin, then the resin is partially cured in acid medium, the level of volatile compounds being between 5 and 8% of the weight of the sheet.

[0091] Once this transformation step is completed, the pattern created by the watermarked Décor paper is visible on the laminate by reflection. That is to say that the watermark 11a pattern formed on the Décor paper 11 is visible to the naked eye directly on the laminate 20.

[0092] According to another specific embodiment and optionally, the Décor paper 11 can be embossed during the lamination step in order to provide this Décor paper 11 with a three-dimensional form if needed to further enhance the visual effect of the pattern created by the watermark.

[0093] The invention is not, of course, limited to what has been described. In particular, although the invention allows an aesthetic appearance to be given to the laminate without printing the Décor paper, the invention does not rule out the Décor paper being printed in order to provide additional and/or complementary effects.