IMPREGNATED CORE PAPER FOR DECORATIVE LAMINATE

Abstract

An impregnated core paper for a decorative laminate, in particular high-pressure decorative laminate, obtained by impregnating a paper substrate with an aqueous impregnating composition including one or more resins selected from melamine-ether resins, acrylic resins, epoxy resins, and mixtures thereof.

Claims

1. An impregnated core paper for a decorative laminate, obtained by impregnating a paper substrate with an aqueous impregnating composition comprising one or more resins selected from melamine-ether resins, acrylic resins, epoxy resins, and mixtures thereof.

2. The impregnated core paper according to claim 1, wherein the impregnating composition is substantially free of phenol-formaldehyde resin.

3. The impregnated core paper according to claim 1, wherein the impregnating composition comprises a water-soluble polymer.

4. The impregnated core paper according to claim 1, wherein the paper substrate comprises at least 45% dry weight of cellulosic fibers based on the total dry weight of the paper substrate.

5. The impregnated core paper according to claim 1, wherein the paper substrate comprises cellulose fibers and at least one thermofusible synthetic compound in a mass ratio by dry weight greater than or equal to 1:1 and less than or equal to 15:1 of the totality of the cellulose fibers relative to the totality of the thermofusible synthetic compound(s).

6. The impregnated core paper according to claim 5, wherein the thermofusible synthetic compound comprises or consists of a thermoplastic polymer.

7. The impregnated core paper according to claim 1, wherein the dry weight of the of the impregnating composition is between 15% and 45% of the total dry weight of the impregnated core paper.

8. The impregnated core paper according to claim 1, wherein the impregnated core paper has a basis weight of between 50 and 400 g/m.sup.2.

9. The impregnated core paper according to claim 1, wherein the paper substrate comprises at least one filler and/or at least one pigment.

10. The impregnated core paper according to claim 9, wherein the dry weight of the filler and/or pigment is between 5% and 40% of the total dry weight of the impregnated core paper.

11. The impregnated core paper according to claim 1, wherein the impregnating composition is substantially free of free-formaldehyde.

12. A method of manufacturing an impregnated core paper according to claim 1, comprising impregnating a paper substrate with an aqueous impregnating composition comprising one or more resins selected from melamine-ether resins, acrylic resins, epoxy resins, and mixtures thereof.

13. The method according to claim 12, wherein the paper substrate is impregnated online on the paper machine.

14. The method according to claim 12, characterized in that the paper substrate is impregnated to a degree of saturation of between 15 and 45% by dry weight.

15. A core for a decorative laminate, comprising at least one sheet of impregnated core paper as defined according to claim 1 or obtained according to the process as defined in claim 12, overlapping at least partially.

16. A decorative laminate, comprising a core according to claim 15.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0104] FIG. 1 is a partial schematic cross-section of an example of a decorative laminate according to the invention, and

[0105] FIG. 2 is a view similar to FIG. 1 of an alternative embodiment.

DETAILED DESCRIPTION

[0106] An example of a decorative laminate 10, specifically, a high-pressure decorative laminate, in accordance with the invention, is shown in FIG. 1. In this figure, the actual proportions are not shown for the sake of clarity.

[0107] The decorative laminate 10 includes a core 15 comprising three sheets of impregnated core paper 12 in accordance with the invention.

[0108] Of course, the number of impregnated core paper sheets 12 forming the core 15 shown in FIG. 1 is only a non-limiting example of an embodiment.

[0109] The core 15 may comprise between 1 and 100 sheets of impregnated core paper 12 according to the invention, in particular between 20 and 50 sheets of impregnated core paper 12 according to the invention.

[0110] The core 15 is covered on each of its two main opposing surfaces by a sheet of decorative paper 11.

[0111] Optionally, an intermediate sheet 13 such as a contrasting paper sheet may be interposed between the core 15 and any or all of the sheets of decorative paper 11.

[0112] Optionally, any or all of the sheets of decorative paper 11 may be covered on its outside by a protective sheet 14, called an overlay.

[0113] The decorative paper sheet 11 may be impregnated with resin, in particular, thermosetting resin, for example, melamine-formaldehyde resin.

[0114] In an embodiment illustrated in FIG. 2, the decorative laminate 10 comprises a sheet of decorative paper 11, in particular impregnated with resin, optionally covering an intermediate sheet 13 and a core 15 comprising one or more sheets of impregnated core paper 12 according to the invention.

[0115] The decorative paper sheet 11 may optionally be covered by a protective sheet 14, called an overlay.

[0116] The assembly constituted by the sheets of impregnated core paper 12 forming the core 15, by the sheet of decorative paper 11, by the optional intermediate sheet 13. and by the optional protective sheet 14 is glued on a support 40 such as chipboard, for example.

EXAMPLES

[0117] The following examples serve only to illustrate the invention and are in no way intended to limit the invention. Indeed, various modifications of the invention, in addition to those described below, will become apparent to the skilled person from the above description and the examples below and will fall within the scope of the claims. The following tests were carried out in order to evaluate the properties of the impregnated core papers obtained according to the invention with respect to known counterexamples of the prior art (comparative examples).

TABLE-US-00001 TABLE 1 Influence of the Impregnation Composition Laminate obtained after lamination Testing according Impregnated core paper to Composition of Number standard the solid part (dry of sheets DIN extract) of the Degree of EN Paper substrate impregnation of impregnated Core 438- before composition saturation core thickness Laminate 2:2019- impregnation (% by weight) (%) paper (m) cohesion 03 Prior Art Kraft paper 100% Phenol N/A 8 2369 + + Reference sheet formaldehyde resin Example 1 A 100% 21.4 20 2460 + + (According to SA Latex 1 the invention) Example 2 A 100% 21.4 20 2516 + + (According to SA Latex 2 the invention) Example 3 A Vinyl acetate, 20.9 20 2430 + (counter- vinyl chloride, example) ethylene copolymer Example 4 A 100% 20.7 20 2572 + (counter- SB Latex example) Example 5 A 100% 22.6 20 2532 + (counter- Polyurethane example) dispersion Example 6 A 100% 20.9 20 N/A N/A (counter- Modified paraffin example) wax emulsion Example 7 A 100% 21.2 20 N/A N/A (counter- Synthetic wax example) emulsion Example 8 A 100% 17.9 20 2509 + (counter- Sulfo-polyester example) Example 9 A 75% SA latex, 18.6 20 2546 + + (According to 25% starch the invention) Example 10 A 50% SA latex, 14.3 20 N/A N/A (counter- 50% starch example) Example 11 A 25% SA latex, 12.5 20 N/A N/A (counter- 75% starch example) Example 12 A 100% Starch 13.2 20 N/A N/A (counter- example) Example 13 B 55% SA latex, 19.8 40 N/A N/A (counter- 45% starch example) Example 14 B 100% starch 19.5 40 N/A N/A (counter- example) Example 15 B 100% SA latex 19.2 40 2592 + + (According to the invention) Example 16 B 100% ULF 19.1 40 2518 + + (According to melamine-ether the invention) Example 17 A 100% ULF 20.1 20 2543 + + (According to melamine-ether the invention) Example 18 B 92% SA latex, 8% 16.3 40 2385 + + (According to PVOH the invention) Example 19 B 55% SA latex, 19.1 40 2500 + (counter- 45% starch example) Example 20 B 70% SA latex, 5% 19.6 40 2483 + + (According to PVOH, 25% the invention) Melamine-ether Example 21 A 92% SA latex, 8% 12.2 20 2558 + + (According to PVOH the invention) Example 22 A 55%, SA latex, 13.0 20 N/A N/A (counter- 45% starch example) Example 23 A 70% SA latex, 5% 22.4 20 2536 + + (According to PVOH, 25% the invention) Melamine-ether Example 24 B 100% 19.2 40 2313 + (counter- KEM-101-50 example) Example 25 B 86% KEM-101- 18.9 40 2342 + + (According to 50 + the invention) 14% KH 700 Example 26 B 86% KEM-101- 20 40 2342 + + (According to 50 + the invention) 14% KH 720 Example 27 B 86% Mixture 1:1 18.9 40 2367 + + (According to KEM-101- the invention) 50/Acronal S305D + 14% KH 700 Example 28 B 86% Mixture 1:1 19.5 40 2390 + + (According to KEM-101- the invention) 50/Acronal S305D + 14% KH 720 Example 29 B 86% Mixture 1:1 18.8 40 2422 + + (According to KEM-101- the invention) 50/Stabilys A040 + 14% KH 720 Paper substrate A: fiber = 100% cellulose, basis weight = 125 g/m.sup.2, 0% pigments, Gurley porosity of 8 sec. Paper substrate B: fiber = 100% cellulose, basis weight = 67 g/m.sup.2, 23% pigments (TiO.sub.2) in dry weight compared to the total dry weight of the paper substrate before impregnation, Gurley porosity of 10 sec. SA Latex: styrene-acrylic latex SB latex: styrene-butadiene latex ULF Melamine-ether: ultra-low formaldehyde melamine-ether resin. KEM-101-50: epoxy resin (polymer of 4,4-(1-Methylethylidene) bisphenol with 2,2-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)[bis[oxirane]; CAS: 25036-25-3) KH 700: polyamine hardener (water soluble polyamine) KH 720: polyamine hardener (polyamine emulsion) Acronal S305D: styrene-acrylic latex Stabilys A040: starch Decorative laminate cohesion (+): presence of cohesion between the sheets of the decorative laminate after lamination Decorative laminate cohesion (): absence of cohesion between the sheets of the decorative laminate after lamination Test according to the standard DIN EN 438-2:2019-03 (+): absence of delamination of the decorative laminate sheets Test according to the standard DIN EN 438-2:2019-03 (): delamination of decorative laminate sheets

[0118] In the examples in Table 1, two different paper substrates were size-press impregnated with different impregnation compositions and then dried to form impregnated core paper sheets 12.

[0119] A plurality of sheets of impregnated core paper 12 for each impregnating composition were then stacked to form a core 15, the core 15 being covered on its upper side with a sheet of impregnated decorative paper 11, and optionally on its underside with another sheet of impregnated decorative paper 11. The assembly was then laminated to form a decorative laminate 10. The laminating conditions used are as follows: [0120] in a first step lasting 30 minutes, a temperature rise from 30 C. to 150 C. is applied to the stack, then [0121] in a second step lasting 12.5 minutes, the temperature applied to this stack is maintained at 150 C., then [0122] in a third step lasting 5 minutes, the temperature applied to the stack is lowered from 30 C. to 150 C., then A pressure of approximately 10 MPa is applied to the decorative laminate 10 during all three steps above.

[0123] When the decorative laminate 10 shows cohesion after laminating the impregnated core paper sheets 12, this decorative laminate 10 is subjected to the test according to the standard DIN EN 438-2:2019-03, which consists of immersing the decorative laminate 10 in boiling water for 2 hours and then evaluating the swelling of the decorative laminate 10 and a possible delamination of the individual sheets forming the decorative laminate 10.

[0124] The impregnating compositions comprise about 30% by weight solids (i.e., about 30% solids by weight) and 70% water by weight. The composition of the solid part (dry extract) of the different impregnation compositions is shown in Table 1.

[0125] It may be seen in Table 1 that the impregnation compositions of Examples 6, 7, 10-14, and 22 do not result in a decorative laminate 10 with cohesion after laminating the impregnated core paper sheets 12.

[0126] The impregnation compositions of Examples 3-5, 8, 19, and 24 provide a decorative laminate 10 with cohesion after laminating the impregnated core paper sheets 12, but the decorative laminate 10 loses cohesion and delaminates when tested according to the standard DIN EN 438-2:2019-03.

[0127] Similar to the example of prior art reference, the impregnation compositions of Examples 1, 2, 9, 15-18, 20, 21, 23, 25-29 (examples according to the invention) provide a decorative laminate 10 that exhibits cohesion after laminating the impregnated core paper sheets 12, and this cohesion is retained when the decorative laminate 10 is subjected to the standard DIN EN 438-2:2019-03 test. Thus, the examples according to the invention have similar performance to the example of prior art reference.

TABLE-US-00002 TABLE 2 Influence of the Presence of Fillers and/or Pigments in the Paper Substrate Impregnated core paper Fillers or Pigments Laminate obtained (in dry after lamination Composition of weight in Testing the solid part relation to according (dry extract) of the total dry to the Paper substrate before the weight of standard impregnation impregnation Degree of the DIN EN Reference composition saturation impregnated Laminate 438- No. Fibers (% by weight) (%) core paper) cohesion 2:2019-03 Example 30 C 100 parts 100% ULF 18.6 0% + + (According natural melamine- to the cellulose ether invention) Example 31 C 100 parts 100% ULF 20.7 20% + ++ (According natural melamine- calcined Compared to the cellulose ether clay with invention) Example 30 Example 32 C 100 parts 100% ULF 17.8 20% TiO.sub.2 + ++ (According natural melamine- Compared to the cellulose ether with invention) Example 30 Example 33 C 100 parts 55% SA latex, 11.7 0% N/A (counter- natural 45% starch example) cellulose Example 34 C 100 parts 55% SA latex, 12.3 22% clay + (counter- natural 45% starch example) cellulose Example 35 C 100 parts 55% SA latex, 11.7 22% talc + (counter- natural 45% starch example) cellulose Example 36 C 100 parts 55% SA latex, 14.3 21% + + (According natural 45% starch calcined to the cellulose clay invention) Example 37 C 100 parts 55% SA latex, 14.9 21% TiO.sub.2 + + (According natural 45% starch to the cellulose invention) C: basis weight = 80 g/m.sup.2; refining energy = 150 kWh/t Decorative laminate cohesion (+): presence of cohesion between the sheets of the decorative laminate after lamination Decorative laminate cohesion (): absence of cohesion between the sheets of the decorative laminate after lamination Test according to the standard DIN EN 438-2:2019-03 (+): absence of delamination of the decorative laminate sheets Test according to the standard DIN EN 438-2:2019-03 (++): improvement in strength Test according to the standard DIN EN 438-2:2019-03 (): delamination of decorative laminate sheets

[0128] In the examples in Table 2, paper substrates containing various fillers or pigments in their mass were impregnated by size-press with an impregnating composition (at 30% dry matter) containing either 100% by weight of a ULF melamine-ether resin (100% by weight of dry matter), or 55% by weight (55% by weight of dry matter) of a styrene-acrylic latex (SA Latex) and 45% by weight (45% by weight of dry matter) of starch, and then dried so as to form impregnated core paper sheets 12.

[0129] Similar to the examples in Table 1, the impregnated core paper sheets 12 were then laminated together under the laminating conditions indicated for the tests in Table 1 to form a decorative laminate 10. When the decorative laminate 10 shows cohesion after laminating the impregnated core paper sheets 12, this decorative laminate 10 is subjected to the test according to the standard DIN EN 438-2:2019-03, which consists of immersing the decorative laminate 10 in boiling water for 2 hours and then evaluating the swelling of the decorative laminate 10 and a possible delamination of the individual sheets forming the decorative laminate 10.

[0130] By comparing Examples 30 to 32, it may be observed that the presence of 20% dry weight of calcined clay (Example 31) or TiO.sub.2 (Example 32) based on the total dry weight of the paper substrate after impregnation improves the strength of the decorative laminate 10 to the test according to the standard DIN EN 438-2: 2019-03 because the increase in thickness and the increase in mass of the decorative laminate 10 as a result of the test according to the standard DIN EN 438-2:2019-03 are limited in Examples 31 and 32 compared to the results obtained for example 30.

[0131] By comparing Examples 33 to 35, it may be seen that the presence of 22% dry weight of clay (Example 34) or talc (Example 35) based on the total dry weight of the paper substrate after impregnation provides cohesion to the decorative laminate 10 obtained by laminating the impregnated core sheets 12. On the other hand, the presence of these fillers does not maintain the cohesion of the decorative laminate 10 when tested according to the standard DIN EN 438-2:2019-03 since delamination is observed.

[0132] By comparing Examples 33 and 36-37, it may be seen that the presence of 21% dry weight of calcined clay (Example 36) or TiO.sub.2 (Example 37) based on the total dry weight of the paper substrate after impregnation results in a cohesive decorative laminate 10, the cohesion of which is maintained when the decorative laminate 10 is subjected to the standard DIN EN 438-2:2019-03 test.

[0133] Thus, for a given impregnation composition, the presence of fillers and/or pigments in the mass of the paper substrate may increase the cohesion of the decorative laminate 10 obtained by laminating the impregnated core paper sheets 12 and/or its test strength according to the standard DIN EN 438-2:2019-03. This effect may be explained by the fact that the presence of fillers and/or pigments results in a modification of the porous structure of the paper substrate, which allows its impregnation in a faster and more homogeneous way. Thus, for given impregnation conditions, the degree of saturation, i.e., of the amount of impregnating composition in the impregnated core paper 12, is increased.

[0134] For a given paper substrate and given impregnation conditions, the variations in the degree of saturation obtained for different impregnation compositions may be explained by the variations in viscosity of the impregnation composition. The less viscous the impregnating composition is, the more it will penetrate the paper substrate, and therefore the higher the degree of saturation.

TABLE-US-00003 TABLE 3 Influence of the Presence of Synthetic Fibers in the Paper Substrate Impregnated core paper Fillers or Laminate obtained Pigments after lamination Composition (in dry Testing of the solid weight in according part (dry relation to to the extract) of the the total dry standard Paper substrate before weight of impregnation impregnation Degree of the DIN EN Reference composition saturation impregnated Laminate 438- No. Fibers (% by mass) (%) core paper) cohesion 2:2019-03 Example C 100 parts 100% ULF 17.8 20% TiO.sub.2 + + 32 natural melamine- (According cellulose ether to the invention) Example C 80 parts 100% ULF 18.3 20% TiO.sub.2 + ++ 38 natural melamine- Compared (According cellulose ether with to the + Example invention) 20 parts 32 Kuralon VPB 101 Example C 60 parts 100% ULF 19.2 20% TiO.sub.2 + ++ 39 natural melamine- Compared (According cellulose ether with to the + Example invention) 40 parts 38 Kuralon VPB 101 Example C 80 parts 100% ULF 19.8 20% TiO.sub.2 + ++ 40 natural melamine- Compared (According cellulose + ether with to the 20 parts Example invention) N720 32 Example C 60 parts 100% ULF 21.6 20% TiO.sub.2 + ++ 41 natural melamine- Compared (According cellulose ether with to the + Example invention) 40 parts 40 N720 Example C 80 parts 100% ULF 20.2 20% TiO.sub.2 + ++ 42 natural melamine- Compared (According cellulose ether with to the + Example invention) 20 parts 32 N720H Example C 60 parts 100% ULF 22.5 19% TiO.sub.2 + ++ 43 natural melamine- Compared (According cellulose ether with to the + Example invention) 40 parts 42 N720H Example C 100 parts 55% SA latex, 14.9 21% TiO.sub.2 + + 37 natural 45% starch (According cellulose to the invention) Example C 80 parts 55% SA latex, 17.6 21% TiO.sub.2 + ++ 44 natural 45% starch Compared (According cellulose with to the + Example invention) 20 parts 37 Kuralon VPB 101 Example C 60 parts 55% SA latex, 17.9 20% TiO.sub.2 + ++ 45 natural 45% starch Compared (According cellulose + with to the 40 parts Example invention) Kuralon 44 VPB 101 Example C 80 parts 55% SA latex, 18.1 20% TiO.sub.2 + ++ 46 natural 45% starch Compared (According cellulose with to the + Example invention) 20 parts 37 N720 Example C 60 parts 55% SA latex, 19.4 20% TiO.sub.2 + ++ 47 natural 45% starch Compared (According cellulose with to the + Example invention) 40 parts 46 N720 Example C 80 parts 55% SA latex, 17.9 20% TiO.sub.2 + ++ 48 natural 45% starch Compared (According cellulose with to the + Example invention) 20 parts 37 N720H Example C 60 parts 55% SA latex, 20.1 20% TiO.sub.2 + ++ 49 natural 45% starch Compared (According cellulose + with to the 40 parts Example invention) N720H 48 C: basis weight = 80 g/m.sup.2; refining energy = 150 kWh/t SA Latex: styrene-acrylic latex ULF Melamine Ether: ultra-low formaldehyde melamine-ether resin Kuralon VPB 101: PVA synthetic fibers (2.9 dtex; 17 m diameter; 4 mm length; melting point: 80 C.) N720: bi-component polyester/PET synthetic fibers (2.2 dtex; 14 m diameter; 5-10 mm length; melting point 110 C.) N720H: bi-component polyester/PET synthetic fibers (2.3 dtex; 15 m diameter; 5 mm length; melting point: 130 C.) Decorative laminate cohesion (+): presence of cohesion between the sheets of the decorative laminate after lamination Decorative laminate cohesion (): absence of cohesion between the sheets of the decorative laminate after lamination Test according to the standard DIN EN 438-2:2019-03 (+): absence of delamination of the decorative laminate sheets Test according to the standard DIN EN 438-2:2019-03 (++): improvement in strength Test according to the standard DIN EN 438-2:2019-03 (): delamination of decorative laminate sheets

[0135] In the examples in Table 3, paper substrates containing 20% TiO.sub.2 by dry weight based on the total dry weight of the paper substrate after impregnation and different mixtures of cellulose fibers and synthetic fibers were impregnated by size-press with an impregnating resin containing in dry extract either 100% by weight of a ULF melamine-ether resin or 55% by weight of a styrene-acrylic latex (SA Latex) and 45% by weight of starch, and then dried to form impregnated core paper sheets 12.

[0136] Similar to the examples in Table 1 and 2, the impregnated core paper sheets 12 were then laminated together under the laminating conditions indicated for the tests in Table 1 to form a decorative laminate 10. When the decorative laminate 10 shows cohesion after laminating the impregnated core paper sheets 12, this decorative laminate 10 is subjected to the test according to the standard DIN EN 438-2:2019-03, which consists of immersing the decorative laminate 10 in boiling water for 2 hours and then evaluating the swelling of the decorative laminate 10 and optional delamination of the individual sheets 12 forming the core 15.

[0137] By comparing Examples 32 and 38, 32 and 40, 32 and 42, we see that the presence of synthetic fibers in the paper substrate makes it possible to improve the strength of the decorative laminate 10 when tested according to the standard DIN EN 438-2:2019-03 because the increase in thickness and the increase in mass of the decorative laminate 10 as a result of the test according to the standard DIN EN 438-2:2019-03 are reduced in Examples 38, 40 and 42 in comparison to Example 32. The same observations are made when comparing Examples 37 and 44, 37 and 46, 37 and 48.

[0138] By comparing Examples 38 and 39, 40 and 41, 42 and 43, we see that increasing the proportion of synthetic fibers within the paper substrate further improves the strength of the decorative laminate 10 against the standard DIN EN 438-2:2019-03 test. The same observations are made when comparing Examples 44 and 45, 46 and 47, 48 and 49.

[0139] Thus, for a given impregnation composition, the presence of synthetic fibers in the paper substrate may increase the strength of the decorative laminate 10 obtained by laminating the impregnated core paper sheets 12 to the test according to the standard DIN EN 438-2:2019-03. This effect may be explained by the fact that the presence of synthetic fibers makes it possible to increase, for given impregnation conditions, the degree of saturation, i.e., the amount of impregnation composition in the impregnated core paper 12.

[0140] Furthermore, the examples in Table 3 show that for a given impregnation composition and a given proportion of synthetic fibers in the paper substrate, the strength is improved as the melting point of the synthetic fibers increases. This may be explained by the fact that a sufficiently high melting point of the synthetic fibers allows the synthetic fibers to melt only during the HPL laminating process carried out under heat and not beforehand, especially during the production of the paper substrate on the paper machine. Melting the synthetic fibers during laminating then allows the synthetic fibers to act as an adhesive between the impregnated core paper sheets 12 (heat bonding) and thus increase the cohesion and strength of the core 15 and thus the decorative laminate 10.

[0141] As will be understood from the preceding description of the present invention and the illustrative experimental examples, the present invention can be described by reference to the following embodiments: [0142] 1. Impregnated core paper (12) for a decorative laminate (10), in particular high-pressure decorative laminate, obtained by impregnating a paper substrate with an aqueous impregnating composition comprising one or more resins selected from melamine-ether resins, acrylic resins, epoxy resins, and mixtures thereof. [0143] 2. Impregnated core paper (12) according to embodiment 1, characterized in that the impregnating composition comprises a melamine-ether resin, in particular at least 90%, better still at least 95%, by dry weight of a melamine-ether resin, or an acrylic resin, in particular at least 90%, better still at least 95%, by dry weight of an acrylic resin, or a mixture of epoxy resin and hardener, in particular at least 90%, better still at least 95%, by dry weight of this mixture. [0144] 3. Impregnated core paper (12) according to embodiment 1 or 2, characterized in that the impregnating composition comprises a water-soluble polymer, in particular selected from a starch, a modified starch, a polyvinyl alcohol, and mixtures thereof. [0145] 4. Impregnated core paper (12) according to any of the preceding embodiments, characterized in that the paper substrate comprises at least 45% dry weight, better still at least 90% dry weight, even better still at least 95% dry weight, of cellulosic fibers based on the total dry weight of the paper substrate. [0146] 5. Impregnated core paper (12) according to any of the preceding embodiments, characterized in that the paper substrate comprises cellulose fibers and at least one thermofusible synthetic compound in a mass ratio by dry weight greater than or equal to 1:1 and less than or equal to 15:1 of the totality of the cellulose fibers relative to the totality of the thermofusible synthetic compound(s), more preferably greater than or equal to 1:1 and less than or equal to 10:1, even more preferably greater than or equal to 1:1 and less than or equal to 4:1. [0147] 6. Impregnated core paper (12) according to embodiment 5, characterized in that the thermofusible synthetic compound comprises or consists of a thermoplastic polymer, the thermoplastic polymer being selected in particular from the families of acrylic polymers, polyurethanes, polyolefins, especially polyethylene (PE) polypropylene (PP), ethylene-vinyl acetate (EVA), ethylene acrylic acid (EAA), ethylene methacrylate (EMA), ethylene methyl methacrylate (EMMA), polyvinylidene chloride (PVDC), polyesters (PES) especially polyethylene terephthalate (PET), polylactic acid (PLA), polyamides, polyvinyl alcohol (PVA or PVOH), polyvinyl chloride (PVC), ethylene vinyl alcohol (EVOH), polyvinylidene fluoride (PVDF) their copolymers and mixtures thereof, the thermofusible synthetic compound being in particular in the form of fibers, in particular selected from among single-component, multi-component, in particular two-component fibers, and mixtures thereof. [0148] 7. Impregnated core paper (12) according to any of the preceding embodiments, characterized in that the dry weight of the impregnating composition is between 15% and 45%, preferably between 15% and 30%, of the total dry weight of the impregnated core paper. [0149] 8. Impregnated core paper (12) according to any of the preceding embodiments, characterized in that the impregnated core paper (12) has a weight of between 50 and 400 g/m.sup.2, preferably between 60 and 200 g/m.sup.2. [0150] 9. Impregnated core paper (12) according to any of the preceding embodiments, characterized in that the paper substrate comprises at least one filler and/or at least one pigment, in particular selected from mineral pigments, such as for example titanium dioxide, clays, calcined clays, talc, calcium carbonate, iron oxides, kaolin, calcined kaolin, diatomaceous earth, silicas, especially colloidal silicas, organic pigments, such as azo compounds or naphthols, synthetic pigments, barium sulfate, aluminum tri-hydrate and mixtures thereof, preferably selected from titanium dioxide, calcined clays and mixtures thereof. [0151] 10. Impregnated core paper (12) according to embodiment 9, characterized in that the dry weight of the filler and/or pigment is between 5% and 40%, preferably between 8% and 36%, of the total dry weight of the impregnated core paper. [0152] 11. Method of manufacturing an impregnated core paper (12) according to any of embodiments 1 to 10, comprising impregnating a paper substrate with an aqueous impregnating composition comprising one or more resins selected from melamine-ether resins, acrylic resins, epoxy resins, and mixtures thereof. [0153] 12. Method according to embodiment 11, characterized in that the paper substrate is impregnated in line on the paper machine, preferably by size-press. [0154] 13. Method according to embodiment 11 or 12, characterized in that the paper substrate is impregnated to a degree of saturation of between 15% and 45%, preferably between 15% and 30%, by dry weight.

[0155] 14. Core (15) for a decorative laminate (10), in particular a high-pressure decorative laminate, comprising at least one sheet of impregnated core paper (12) as defined according to any of embodiments 1 to 10 or obtained according to the process as defined in any of embodiments 11 to 13, in particular at least two sheets, preferably between 10 and 100 sheets, even better between 20 and 50 sheets, overlapping at least partially, better still completely. [0156] 15. A decorative laminate (10), in particular a high-pressure decorative laminate, comprising a core (15) according to embodiment 14, and in particular at least one impregnated decorative paper sheet (11) placed upon at least one of the two opposite main surfaces of the core (15).