Paper for decorative coating materials containing pigment-bearing synthetic fibres

Abstract

The invention relates to a paper for decorative coating materials, said paper containing cellulose fibres and synthetic fibres, wherein the synthetic fibres contain at least one polymer and at least one pigment, and the mass ratio of pigment to polymer in the synthetic fibres is 1:10 to 1:1. The invention also relates to: a decorative paper or a decorative film containing the paper according to the invention; and to a method for manufacturing the paper according to the invention, said method comprising the following steps: (a) providing a cellulosic pulp mixture, (b) refining the cellulosic pulp mixture to a degree of refinement of 10 to 45°SR, (c) optionally adding fillers and wet-strength agents to the refined cellulosic pulp mixture obtained in (b), (d) diluting the mixture obtained in (c), (e) optionally adding auxiliary agents, (f) forming a nonwoven fabric, (g) dewatering and drying the nonwoven fabric in order to obtain the paper, wherein the synthetic fibres, which contain at least one polymer and at least one pigment and have a mass ratio of pigment to polymer of 1:10 to 1:1, are added after step (d) and before step (f).

Description

[0001] Paper for decorative coating materials containing pigmented synthetic fibers

[0002] The invention relates to a paper for decorative coating materials, in particular a decorative base paper, with synthetic fibers containing pigment and polymer, for applications requiring high opacity of the paper, and to a process for its production. Furthermore, the invention relates to a decorative paper or a decorative film containing the paper according to the invention.

[0003] Decorative coating materials, so-called decorative papers or decorative films, are primarily used for surface coating in furniture manufacturing and interior design, especially for laminate flooring. Decorative paper / decorative film refers to papers impregnated with synthetic resin or impregnated with synthetic resin and surface treatment, printed or unprinted.

[0004] Decorative papers / decorative films are glued or bonded to a carrier board.

[0005] Depending on the type of impregnation process, a distinction is made between decorative papers / decorative films with a fully impregnated paper core and so-called pre-impregnated papers, in which the paper is only partially impregnated online or offline in the paper machine.

[0006] High-pressure laminates are laminates created by pressing several impregnated papers together. These laminates generally consist of a resin-impregnated decorative paper and one or more phenolic resin-treated kraft papers. Surface durability can be increased by incorporating a transparent overlay. Examples of substrates used for this include hardboard, particleboard, and plywood. Low-pressure laminates, manufactured using the short-cycle process, involve pressing the resin-impregnated decorative paper directly onto a substrate, such as particleboard, at a lower pressure.

[0007] Urea glues, hot melts or polyvinyl acetate (PVAC) glues are commonly used to bond the pre-impregnated materials to wood materials such as chipboard or MDF boards.

[0008] The decorative base paper used for the above-mentioned coating materials is white or colored with or without additional printing.

[0009] In terms of application properties, the decorative base papers used as starting materials, known as raw materials, must meet certain requirements. These include high opacity for better coverage of the substrate, uniform sheet formation and grammage for consistent resin absorption, high lightfastness, high color purity and uniformity for good reproducibility of the printed pattern, high wet strength for smooth impregnation (saturation), appropriate absorbency to achieve the required resin absorption, and dry strength, which is important during rewinding processes in the paper machine and during printing on the press. Furthermore, the split strength (strength in the z-direction) is of particular importance, as it is a measure of how well the decorative base paper can be processed. For example, the glued or laminated decorative paper / decorative film must not fray during processing steps such as sawing or drilling.

[0010] Decorative base papers generally consist of high-white sulfate pulps, predominantly hardwood pulp, with a high content of pigments and fillers, as well as wet strength agents, retention agents, and fixatives. Decorative base papers differ from conventional papers in their much higher filler content and the absence of the usual machine sizing or surface sizing with known sizing agents such as alkyl ketene dimers. Opacity is one of the most important properties of decorative base paper. It indicates its ability to cover the substrate.

[0011] Opacity is caused by light scattering by the pigment particles. To achieve high light scattering power, it is advantageous to use pigment particles of a specific size and a narrow size distribution. Furthermore, it is also advantageous if the light-scattering pigment particles are distributed as evenly as possible in the medium to be opaqued. Clumping of pigment particles reduces the effectiveness of light scattering.

[0012] Particularly when pigments are added during paper production, a clumping of the pigment particles is usually observed, resulting in microscopic areas in the paper where a large number of pigment particles are arranged closely together. Other areas of the sheet, in contrast, contain only a few pigment particles, so that light passes through these areas largely unhindered and with little or no scattering. This uneven distribution results in a reduced opacity of the paper, which must be compensated for by increasing the use of pigment. However, the pigment content cannot be increased indefinitely, as this would likely impair physical properties such as the retention behavior of the pulp suspension, strength, and resin absorption.

[0013] Various proposals have been made to improve the uniform distribution of pigment particles.

[0014] US 4,608,401 describes a process for encapsulating titanium dioxide particles with a water-insoluble polymer in an aqueous suspension and the use of the resulting particles in paints. DE 199 61 964 A1 describes a process for producing an aqueous dispersion of composite particles consisting of a finely divided inorganic solid and a polymer. However, the described teachings are not advantageously applicable to decorative base papers because, on the one hand, the achievable spacing between the pigment particles is too small, and, on the other hand, the pore volume of the decorative base paper is reduced by the soft polymer latex components of these pigment preparations, which adversely affects the impregnability of the base paper.

[0015] GB 487 835 describes preparations of dyes and colour pigments with melamine-formaldehyde condensation products as components of paints.

[0016] DE 10 2013 100353 A1 describes a reactive composite composed of titanium dioxide, a binder, and at least one carrier. The carrier is preferably an inorganic material, to which the titanium dioxide particles are applied with a reactive binder to form the so-called reactive composite. The composite is then ground to a specific size and used as a solid powder in paper production.

[0017] EP 3 026 175 A1 describes a paper for decorative coating materials in which pigment resin particles based on hardening resin and pigments are used.

[0018] Although in the latter two cases, the use of these composites or pigment-resin particles does improve the uniform distribution of titanium dioxide in the paper, the disadvantage in both cases is that the production of the composites or pigment-resin particles is very complex. Furthermore, due to their particle size, the composites or pigment-resin particles are retained in paper production just as poorly as the original titanium dioxide. The low retention of the individual composite particles or pigment-resin particles in the paper pulp and the associated material loss necessitate the use of larger quantities of composite or pigment-resin particles. This is uneconomical.

[0019] The invention is therefore based on the object of producing a paper with a high opacity and at the same time a reduced white and / or color pigment content, without the disadvantageous effects of the prior art occurring.

[0020] This object is achieved by a paper for decorative coating materials, containing cellulose fibers and synthetic fibers, wherein the synthetic fibers contain at least one polymer and at least one pigment and the mass ratio of pigment to polymer in the synthetic fibers is 1:10 to 1:1.

[0021] Surprisingly, it has been found that the opacity of the paper according to the invention is significantly increased compared to a conventional decorative base paper with the same amount of pigment particles in a conventional formulation. With the paper according to the invention, the proportion of titanium dioxide in the paper can therefore be significantly reduced while maintaining a consistently high opacity. A further advantage of the paper according to the invention is that up to 40% of impregnating resin can be saved during further processing. Furthermore, due to the simultaneous good retention properties of the synthetic fibers contained in the paper according to the invention, there is significantly less material loss during paper production. This is associated with considerable cost savings.

[0022] In contrast to conventional papers, the paper according to the invention, in particular decorative base paper, is neither pulp sized nor surface sized. It essentially contains pulp, pigment, and optionally a filler and conventional additives. Common additives can be wet strength agents, retention aids, and fixatives. Decorative base paper differs from conventional papers in the much higher filler and pigment content in the sheet and the absence of the pulp sizing or surface sizing typical of paper. Decorative base paper therefore has the ability to absorb an impregnating resin.

[0023] Softwood pulp (long-fiber pulp) and / or hardwood pulp (short-fiber pulp) can be used as pulps for the production of paper, especially decorative base paper. Cotton fibers and mixtures thereof with the aforementioned pulp types can also be used. A mixture of softwood / hardwood pulp in a ratio of 10:90 to 90:10, especially 20:80 to 80:20, is particularly preferred. However, the use of 100% hardwood pulp has also proven advantageous. The quantities refer to the mass of the pulp (dry).

[0024] The pulp mixture can preferably contain a proportion of cationically modified pulp fibers of at least 5 wt.%, based on the weight of the pulp mixture. A proportion of 10 to 50 wt.%, in particular 10 to 20 wt.%, of cationically modified pulp in the pulp mixture has proven particularly advantageous. The cationic modification of the pulp fibers can be achieved by reacting the fibers with an epichlorohydrin resin and a tertiary amine or by reacting them with quaternary ammonium chlorides such as chlorohydroxypropyltrimethylammonium chloride or glycidyltrimethylammonium chloride. Cationically modified pulps and their production are known, for example, from DAS PAPIER, Issue 12 (1980), pp. 575-579.

[0025] The synthetic fibers contained in the paper according to the invention contain at least one pigment and at least one polymer.

[0026] For the purposes of the invention, the term "pigment" refers to finely divided inorganic or organic substances that are naturally or synthetically obtained and serve to achieve opacity or for coloring purposes. In contrast to pigments, the term "filler" refers to finely divided inorganic or organic substances that are naturally or synthetically obtained and do not serve to achieve opacity or for coloring purposes.

[0027] Suitable color pigments for producing the synthetic fibers contained in the paper according to the invention, in particular decorative base paper, are preferably mineral pigments which are used to increase the opacity in paints and coatings, in sheet materials such as paper or plastic films.

[0028] According to a preferred embodiment of the invention, the at least one pigment in the synthetic fibers is selected from one or more pigments having a refractive index of greater than 2 or a mixture of one or more pigments having a refractive index of greater than 2 and one or more pigments having a refractive index of less than 2. The refractive index is determined using the usual methods known to the person skilled in the art at the wavelength of the sodium D line (nD) of 589 nm by means of a refractometer.

[0029] It has proven particularly advantageous if the pigment with a refractive index greater than 2 is titanium dioxide. Due to its high opacity, titanium dioxide is the preferred white pigment for many applications. This applies in particular to use in decorative base papers. Titanium dioxide commonly used in decorative papers can be used as the titanium dioxide for producing the synthetic fibers contained in the decorative base paper according to the invention. Such titanium dioxides are commercially available and can preferably be used in the rutile type. Examples of commercially available titanium dioxides are Ti-Pure® R-796+, Ti-Pure® R 902 from DuPont, KRONOS 2800, and KRONOS 2305.

[0030] In addition to the one or more pigments with a refractive index greater than 2, pigments with a refractive index of less than 2 may also be present in the synthetic fiber. These pigments with a refractive index of less than 2 can preferably be selected from the group consisting of kaolin, calcium carbonate, calcium sulfate, barium sulfate, talc, silica, aluminum oxide, iron oxide, zinc sulfide, calcium carbonate in its natural form, such as limestone, marble, or dolomite, and mixtures thereof. With a mass ratio of pigment to polymer in the synthetic fibers of 1:2 or more, the admixture of one or more pigments with a refractive index of less than 2 to the one or more pigments with a refractive index greater than 2 leads to more efficient use of the pigment with a refractive index greater than 2 while maintaining the same opacity.The pigments with a refractive index of less than 2 act as spacers between the pigments with a refractive index of greater than 2 and thus between the respective scattering centers.

[0031] The proportion of a pigment with a refractive index of less than 2 in the total amount of pigment contained in the synthetic fibers is preferably less than 20 wt.%, in particular less than 10 wt.%. To reliably fulfill the spacer function in the synthetic fibers with a pigment-to-polymer mass ratio of 1:2 or more, the proportion of the pigment with a refractive index of less than 2 in the total amount of pigment contained in the synthetic fibers is at least 5 wt.%.

[0032] The particle size of the pigments in the synthetic fibers used according to the invention is in the range from 10 nm to 5 pm, preferably in the range from 50 nm to 3 pm. In cases where the pigment particles have a non-spherical shape, "particle size" is understood to mean the diameter of a sphere with the same volume as the particle.

[0033] The synthetic fibers contain a polymer in addition to the pigment.

[0034] The polymer used in the synthetic fibers is preferably a substantially cured polymer. Substantially cured means that the polymer has a degree of crosslinking of more than 80%, preferably more than 90%, more preferably more than 95%, and particularly preferably more than 98%. Substantially cured also means that the polymer is not fully cured and is still meltable. In particular, the degree of crosslinking is less than 100%. The degree of crosslinking is determined as specified below.

[0035] Suitable polymers include melamine-formaldehyde resins, melamine-urea-formaldehyde resins, phenol-formaldehyde resins, urea resins, polyurethanes, and mixtures thereof. However, the use of other polymers is also conceivable.

[0036] Melamine-formaldehyde resins are particularly preferred as polymers. Other suitable polymers are polyacrylic or polyacrylic methyl esters, polyvinyl acetate, polyvinyl chloride, and mixtures thereof.

[0037] The mass ratio of pigment to polymer in the synthetic fibers is 1:10 to 1:1, in particular 1:10 to 1:2, preferably 1:7 to 1:3. On the one hand, the fibers can be produced using standard industrial processes in the specified mass ratio. On the other hand, the largest possible amount of pigment is incorporated into the fiber, thereby reducing the amount of pigment used in the actual paper production. The optimal mass ratio is influenced by, among other things, the pigment particle size and the morphology of the particles. However, any other pigment to polymer ratios in the synthetic fibers are also conceivable, as long as the desired high opacity of the decorative base paper is achieved.

[0038] The synthetic fibers are preferably produced from highly concentrated solutions of polymer precondensation products after addition of a hardener and the pigments by centrifugal spinning, thread drawing, extrusion, or fibrillation processes. The synthetic fibers obtained are generally predried, optionally stretched, and the polymer is typically cured at temperatures of 120 to 250°C. According to the invention, however, the polymer must not be fully cured, i.e., the fibers are stable to handle but still meltable. This ensures that the synthetic fibers bond homogeneously with the impregnating resin during further processing of the paper according to the invention into decorative paper or decorative film. The synthetic fibers are usually 1 to 150 μm thick and 200 to 20,000 μm long.

[0039] According to a preferred embodiment of the invention, the synthetic fibers have an average diameter of less than 150 pm, in particular less than 100 pm.

[0040] It has proven particularly practical if the paper according to the invention contains between 3 and 50 wt.%, in particular between 5 and 30 wt.%, particularly preferably between 10 and 25 wt.%, of synthetic fibers, based on the total weight of the paper atro.

[0041] The paper according to the invention, in particular decorative base paper, may contain, in addition to the synthetic fibers, further mineral and non-mineral fillers and pigments.

[0042] According to a preferred embodiment, the pigments contained in the paper as a whole are enclosed in the synthetic fibers to an extent of at least 5% by weight, preferably at least 15% by weight, in particular at least 25% by weight, particularly preferably 35% by weight, based on the total mass of the pigments in the paper.

[0043] Another object of the invention is a process for producing the paper according to the invention, in particular decorative base paper, comprising the following steps:

[0044] (a) providing a pulp mixture,

[0045] (b) refining the pulp mixture to a degree of beating of 10 to 45°SR, (c) optionally adding fillers and wet strength agents to the refining pulp mixture obtained in (b),

[0046] (d) diluting the mixture obtained in (c),

[0047] (e) optional addition of excipients,

[0048] (f) forming a nonwoven fabric,

[0049] (g) dewatering and drying the nonwoven fabric to obtain the paper, wherein the addition of the synthetic fibers containing at least one polymer and at least one pigment and in which the mass ratio of pigment to polymer is 1:10 to 1:1 takes place after step (d) and before step (f).

[0050] The papers according to the invention, in particular decorative base papers, can be produced on a Fourdrinier paper machine. For this purpose, the pulp mixture prepared in step (a) of the process according to the invention is refined in step (b) of the process according to the invention, preferably at a consistency of 2 to 5 wt. %, to a degree of refining of 10 to 45°SR.

[0051] In the optional step (c) of the process according to the invention, fillers and wet strength agents can be added to the ground pulp mixture obtained in step (b), preferably in a mixing vat. Titanium dioxide and talc, for example, can be added as fillers and thoroughly mixed with the pulp mixture.

[0052] The thick stock thus obtained in step (c) of the process according to the invention is diluted in step (d) of the process according to the invention, preferably to a consistency of about 1%, and, if necessary, further auxiliaries, for example retention aids, defoamers, aluminum sulfate, and other aforementioned auxiliaries, are added in optional step (e). This so-called thin stock obtained in step (d) or, if present in step (e), in step (e), is fed to the wire section, preferably via the headbox of the paper machine, to form a nonwoven fabric according to step (f) of the process according to the invention.

[0053] After dewatering and drying in step (g) of the process according to the invention, the paper according to the invention is obtained. The basis weights of the papers produced can be 15 to 300 g / m 2 However, papers with a basis weight of 40 to 100 g / m are particularly suitable. 2 .

[0054] In the process according to the invention, the synthetic fibers are added after step (d) and before step (f). Addition after step (d) and before step (f) of the process according to the invention means that the synthetic fibers are preferably added in the thin stock directly before application via the headbox of the paper machine to the wire section. In this way, the impairment of the fibers by refining and the associated possible contamination of the refining groups can be avoided. To improve the dispersibility of the synthetic fibers in the thin stock, the synthetic fibers can be coated with a surfactant or a surfactant mixture.

[0055] The synthetic fiber can be added alternatively or additionally in step (a) of the process according to the invention, whereby the synthetic fibers are provided with the pulp mixture. In this case, the refining in step (b) of the process according to the invention should be reduced as much as possible to avoid deterioration of the synthetic fibers.

[0056] The invention further relates to a decorative paper or a decorative film containing the paper according to the invention.

[0057] To produce decorative papers or decorative films, the papers, especially decorative base papers, are impregnated or saturated with synthetic resin dispersions commonly used for this purpose. These include, for example, melamine-formaldehyde resins, melamine-urea-formaldehyde resins, phenol-formaldehyde resins, urea resins, polyurethanes and mixtures thereof, or those based on polyacrylic or polyacrylmethyl esters, polyvinyl acetate, polyvinyl chloride, and mixtures thereof.

[0058] Pre-impregnation for decorative films can also be performed in a separate machine pass in the size press or with a film press in the paper machine. Impregnating or soaking the paper with the impregnating resin results in the sheet being essentially free of air pockets. The impregnating resin is distributed evenly throughout the sheet.

[0059] The proportion of impregnating resin, calculated as solids, in the paper amounts to 10 to 40% by weight, based on the paper mass. Because, unlike conventional paper or decorative base paper, impregnated paper essentially contains no air pockets, decorative paper is also referred to as decorative foil.

[0060] The papers can be printed and / or varnished before or after impregnation and then applied to a substrate such as a wooden board.

[0061] The invention is further explained by the following figure and the following examples.

[0062] FIG. 1 Diagram of the opacity of the decorative paper after pressing against the area-related titanium dioxide content for the inventive examples A1 to A4 and the comparative examples C1 to C4 Test methods

[0063] opacity

[0064] Determination according to ISO 16065-1.

[0065] Determination of the ignition residue

[0066] The titanium dioxide content in the decorative base paper was determined according to DIN 54370.

[0067] Average fiber diameter

[0068] The mean diameter of the fibers is determined according to OENORM EN ISO 137 using the microscope projection method.

[0069] Fiber length

[0070] The fiber length is determined according to the ISO 16065-1 standard. Fiber length is measured using automatic optical analysis using polarized light.

[0071] Degree of networking

[0072] The test is used to determine the degree of curing of impregnates.

[0073] For this purpose, test specimens with an area of ​​100 cm 2 punched out and weighed (corresponds to sample weight "before extraction").

[0074] The test specimens are then immersed in N, N-dimethylformamide (DMF) (a 100 cm 2-disk in 100 ml each). After a contact time of 30 minutes at room temperature, the test specimens are removed, placed on blotting paper, and then dried in a drying cabinet at 120 °C for 90 minutes. After cooling, the test specimens are weighed (corresponds to the sample weight "after extraction").

[0075] The degree of cross-linking is then determined using the following formulas:

[0076] Dissolved components = initial weight-output weight

[0077] Sample weight = sample weight "before extraction" - basis weight of raw paper g / m 2 x sample area cm 2 / 10,000

[0078] Final weight = sample weight "after extraction" - basis weight of raw paper g / m 2 x sample area cm 2 / 10,000

[0079] Dissolved parts % = dissolved parts / sample weight x 100

[0080] Crosslinked portion % (degree of crosslinking) = final weight / initial weight x 100

[0081] Examples

[0082] Production of decorative base papers

[0083] The decorative base papers were manufactured using the same process for all examples. Individual components of the recipe were adapted according to the described examples.

[0084] 50 g of eucalyptus pulp are filled with water in a dispersing vessel to achieve a pulp density of approximately 3%.

[0085] For the examples according to the invention, 20% of the eucalyptus pulp is replaced by melamine-formaldehyde fibers with a titanium dioxide content of 30 wt.%. The melamine-formaldehyde fibers have a diameter of 80 pm and a length of 1.5 mm.

[0086] The pulp is stirred for 30 minutes using a laboratory dissolver and a dispersing disc. The resulting pulp slurry is then poured into a dispensing device and topped up with water to a total of 8 liters, achieving a pulp consistency of approximately 1%. An additional 25 g of a 1.5 wt.% solution of an adipic acid-diethylenetriamine-epichlorohydrin copolymer (Giluton® XP 14, BK Giulini GmbH) is added to the dispensing device as a wet strength agent, and the suspension is adjusted to pH 6 with 10% sulfuric acid.

[0087] From the pulp suspension thus produced, individual batches are prepared on the sheet former in the following manner to produce decorative base paper sheets.

[0088] A titanium dioxide preparation (equivalent to approximately 2 g of pure TiC per sheet) is added to each 300 g of the pulp suspension, and the suspension is thoroughly mixed with a paddle stirrer. Then, another 0.95 g of the 1.5 wt% adipic acid diethylenetriamine epichlorohydrin copolymer solution is added and thoroughly mixed.

[0089] The single batch prepared in this way is added to the filling chamber of the sheet former with 2 l of water, filled to a total volume of 4 l and the sheet formation process is started.

[0090] Using pigment resin fibers according to the invention, the individual sheets A1 to A4 were produced and the individual sheets C1 to C4 were produced from the comparative titanium dioxide dispersion.

[0091] The individual sheets Al to A4 and CI to C4 are manufactured using the same process and identical raw materials, with the ash content and the basis weight being varied, and serve for statistical purposes.

[0092] Impregnation and pressing of the inventive and comparative decorative base paper sheets

[0093] To impregnate the individual sheets, a solution containing 52 wt.% melamine-formaldehyde resin (KAURAMIN® 773 from BASF SE) in water is used, to which 1.6 wt.% wetting agent (Hypersal® VXT 3797 from Surface Specialities Germany) and 0.8 wt.% hardener (MADURIT® hardener MH 835 / 70W, available from Ineos Melamines, Germany) is added.

[0094] The decorative base paper sheets are placed on the resin solution until completely saturated, but for at least 60 seconds, and then completely immersed in the resin bath. Excess resin is then doctored off, and the sheet is dried for 25 seconds at 130°C. The sheet is then completely immersed in the resin solution again, excess resin is doctored off, and dried at 130°C to a residual moisture content of 6% by weight.

[0095] The impregnated decorative paper sheets are pressed onto a 40x40 cm laminate panel using the high-pressure pressure process (HPL) at a temperature of 140°C and a pressure of 234 bar for 4 minutes, and then cooled to 60°C in the press. A much smaller black and a white impregnated decorative paper sheet are pressed under the sheet to be tested at two different locations to measure opacity.

[0096] The opacity of the decorative paper sheet to be tested is determined by measuring and comparing reflection densities. A white and a black sheet are placed side by side. The sheet to be tested for opacity is laminated over the white and black sheets and then mounted on a plate. The reflection density measurements on the white and black sheets were performed using a Datacolor 600 colorimeter. The reflection density measured on the black sheet was divided by the reflection density measured on the white sheet, and the result was multiplied by 100.

[0097] The basis weight (determined according to EN ISO 536) of the leaves obtained, their residue on ignition (ash content - determined according to DIN 54370) and the achieved opacity (determined according to ISO 16065-1) are summarized in the table below, whereby the ash content can be equated with the amount of titanium dioxide contained in relation to the leaf weight or leaf area.

[0098] Figure 1 plots the opacity of the decorative paper after pressing against the surface-related titanium dioxide content for the inventive examples A1 to A4 and the comparative examples C1 to C4. The results of the opacity measurement show that the decorative papers containing the inventive decorative base paper (A1 to A4) with melamine-formaldehyde fibers with titanium dioxide exhibit a significantly higher opacity, with a comparable titanium dioxide content, than the decorative papers containing a comparative decorative base paper (C1 to C4) with the comparative preparation.

[0099] By using a decorative base paper according to the invention, a saving of titanium dioxide of at least 20% of the amount can be achieved without the opacity of the decorative paper deteriorating.

[0100] Table 1

Claims

Patent claims 1. Paper for decorative coating materials, containing cellulose fibers and synthetic fibers, characterized in that the synthetic fibers contain at least one polymer and at least one pigment and the mass ratio of pigment to polymer in the synthetic fibers is 1:10 to 1:

1.

2. Paper according to claim 1, characterized in that the paper is a decorative base paper.

3. Paper according to claim 1 or 2, characterized in that the synthetic fibers used have an average diameter of less than 150 pm.

4. Paper according to one of claims 1 to 3, characterized in that the paper contains between 3 and 50% by weight of synthetic fibers, based on the total weight of the paper dry.

5. Paper according to one of claims 1 to 4, characterized in that the pigment is selected from one or more pigments having a refractive index of greater than 2 or a mixture of one or more pigments having a refractive index of greater than 2 and one or more pigments having a refractive index of less than 2.

6. Paper according to claim 5, characterized in that the pigment with a refractive index greater than 2 is titanium dioxide.

7. Paper according to claim 5 or 6, characterized in that the pigment with a refractive index of less than 2 is selected from the group consisting of kaolin, calcium carbonate, calcium sulfate, barium sulfate, talc, silica, aluminum oxide, iron oxide, calcium carbonate in its natural form, such as limestone, marble or dolomite stone, and mixtures thereof.

8. Paper according to one of claims 1 to 7, characterized in that the pigments contained in the paper as a whole are enclosed in the synthetic fibers to an extent of at least 5% by weight, based on the total mass of the pigments in the paper.

9. Paper according to one of claims 1 to 8, characterized in that the polymer is selected from melamine-formaldehyde resin, melamine-urea-formaldehyde resin, urea resin, urea-formaldehyde resin, phenol-formaldehyde resin, polyurethane, polyacrylic ester, polyacrylmethyl ester, polyvinyl acetate, polyvinyl chloride and mixtures thereof.

10. Paper according to claim 9, characterized in that the polymer is a melamine-formaldehyde resin.

11. Paper according to one of the preceding claims, characterized in that the polymer of the synthetic fibers has a degree of crosslinking of more than 80%.

12. Decorative paper or decorative film containing a paper according to one of claims 1 to 11.

13. A process for producing a paper according to any one of claims 1 to 11, comprising the following steps: (a) providing a pulp mixture, (b) refining the pulp mixture to a degree of beating of 10 to 45°SR, (c) optional addition of fillers and wet strength agents to the ground pulp mixture obtained in (b), (d) diluting the mixture obtained in (c), (e) optional addition of auxiliary materials, (f) forming a nonwoven fabric, (g) dewatering and drying the nonwoven fabric to obtain the paper, wherein the addition of the synthetic fibers containing at least one polymer and at least one pigment and in which the mass ratio of pigment to polymer is 1:10 to 1:1 takes place after step (d) and before step (f).

14. The method of claim 14, wherein the synthetic fibers are coated with a surfactant or a surfactant mixture.

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