EP1753818A1

EP1753818A1 - Method for producing coated substrates

Info

Publication number: EP1753818A1
Application number: EP05751297A
Authority: EP
Inventors: Marta Martin-Portugues; Albert Sester; Jakob Decher; Ralph Lunkwitz; Claus Fueger; Thomas Damian; Günter Scherr
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2004-05-27
Filing date: 2005-05-21
Publication date: 2007-02-21
Also published as: WO2005118718A1; US20070172687A1; CA2564692A1

Abstract

The invention relates to a method for producing coated substrates comprising a three-dimensionally structured surface. According to said method, a decorative paper containing between 5 and 90 wt. % synthetic polymer fibres, in relation to the total fibre content, is impregnated with a cross-linkable amino resin, is applied to the substrate and three-dimensionally shaped. The invention also relates to amino resin sheets or films and to the use of a modified decorative paper for amino resin sheets or films for the 3D coating.

Description

Process for the production of coated substrates

Description The invention relates to a method for producing coated substrates. The invention further relates to aminoplast resin films or films, and to the use of a modified decorative paper for producing aminoplast resin films or films for 3D coating.

Thermoplastic films are usually used for coating three-dimensional structured surfaces (3D coating), e.g. for coating wood-based materials in the furniture industry. The significant advantage of these thermoplastic films is their elasticity, disadvantageous are the high costs in production, among other things. caused by the additional use of adhesives.

It is desirable that the self-adhesive inexpensive melamine resins, the z. B. used in the furniture industry for finishing smooth surfaces, also for coating three-dimensional structured surfaces. The melamine resins are also characterized by high gloss and good printability. Pure melamine resins are too brittle for this application.

According to DE-A 23 09 334, improved flexibility of the films could be achieved with melamine resins bearing etherified methyl groups. These melamine resin films are mainly used for surface finishing of wood-based materials such as chipboard, hardboard and blockboard. In order to achieve the flexibility and elasticity required for coating rounded edges, for example, the melamine resins were further modified, e.g. by adding guanamine according to DE-A 4439 156 or by adding small amounts of an aqueous synthetic resin dispersion according to DE-A 38 37965. A combination of aminoplast resins with acrylate dispersions results in a certain elasticity of the films produced according to DE-A 3700 344, however, a high proportion of dispersion caused a substantial loss in overvoltage and splitting resistance; Properties that are particularly important when coating three-dimensional structured surfaces.

The older German application with the file number 10301901.4 for the first time discloses self-adhesive melamine resin films that can be used directly for the 3D coating of furniture. These melamine resins consist of a mixture of melamine-formaldehyde condensates, etherified melamine-formaldehyde condensates and acrylate dispersions. The melamine resin films described are well suited for coating three-dimensionally deformed surfaces. Improved flexibility of the films could also be achieved by modifying the decorative paper to be impregnated with the melamine resin. WO 00/53666, WO 00/53667, WO 00/53668 and WO 02/38345 describe different fiber papers for coating, for example, bodies with three-dimensional structures. WO 00/53666 discloses a carrier made of meltable polymer and cellulose for this purpose or regenerated cellulose. Cellulose esters and preferably cellulose acetate are described as meltable polymers. WO 00/53667 describes fiber papers using carriers based on complete or partial regenerated cellulose. The regeneration of the cellulose consists of a conversion into a soluble cellulose derivative using an acid, the derivative being able to be converted into fibers and optionally reducing the size of the fibers. WO 00/53668 describes carriers made of fibrous cellulose esters, preferably cellulose acetates. WO 02/38345 describes the use of decorative paper, which has a cotton linter content of at least 10% by weight and up to 100% by weight of the total fiber content, for coating three-dimensionally structured surfaces.

The known films or films made from the modified melamine resins and decorative papers are in need of improvement despite the successes achieved so far. In particular, there is still a need for optimization in the property of the elasticity of the foils or films. For aesthetic reasons and at the same time to simplify production, the coating should only be carried out with a single film or film in a single pressing process. The main characteristic of such foils or films lies in their deformability during the pressing process.

The invention was therefore based on the object of finding an improved method for producing a coated substrate with a three-dimensionally structured surface. In particular, a method for producing a coated piece of furniture or wood material with a three-dimensionally structured surface should be provided. Furthermore, a more flexible melamine resin film or film should be found that is also suitable for 3D coating and in particular for the full encasing of structures. The coated surfaces should not have any whitening, i.e. shimmering background and unwanted folds at the upsetting points.

Surprisingly, a process was found which is particularly suitable for the production of partially or fully coated substrates with a three-dimensionally structured surface, in which a decorative paper which contains 5 to 90% by weight, based on the total fiber content, of fibers made of synthetic polymers, impregnated with a crosslinkable aminoplastic resin, applied to a substrate and deformed three-dimensionally. The term “three-dimensional deformation” is to be understood as the partial or complete coating of bodies, structures, reliefs, profiles, embossings and the like. These have three-dimensionally structured surfaces, that is to say shapes, designs or structures that extend in all three spatial directions. The shape changes can be both fluid and abrupt, for example in the case of sharp-edged structures, such as edges, corners and / or tapering, which describe a defined angle which results from two or more planes converging towards one another. Also under "three-dimensional deformation" to understand the full covering, or simultaneous / simultaneous coating of fronts and edges, of regular or irregular shaped bodies, profiles and the like.

Polyamide, polyimide, polyurethane, polypropylene, polyethylene, polyacrynitrile, polyvinyl alcohol or various polyesters, for example polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, are advantageously used as the starting material for the fibers made of synthetic polymers. The use of fibers made of polyamide, polyester, polypropylene or polyethylene is preferred.

Mixtures of fibers made of synthetic polymers are also advantageous. For example, a mixture of two of the above synthetic fibers such as e.g. B. polyamide, polypropylene, polyethylene and polyester fibers are used in a weight ratio of 1:99 to 99: 1. Depending on the specification of the decorative papers to be obtained, advantageous fiber mixtures can be selected, and more than two types of fibers can also be present.

Fibers made of copolymers or polymer blends can also be used, for example block polymers or polymer blends made of polyamide, polyimide, polyurethanes, polypropylene, polyethylene, polyacrynitrile, polyvinyl alcohol or various polyesters, for example polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate. Copolymers of monomers such as propylene, ethylene, (meth) acrynitrile, vinyl alcohol or esters, e.g. B. of vinyl alcohol can also serve as a basis for the production of synthetic fibers.

The fibers made of synthetic polymers advantageously have as little branching as possible, in particular no branching. The length of the individual fibers is similar to that of typical natural fibers. The synthetic fibers advantageously have a length of 0.5 to 20 mm, in particular 0.5 to 10 mm, particularly preferably 2 to 10 mm. The fiber diameter is usually 5 to 30 μm, preferably 10 to 25 μm. The fibers also have an average surface area of 1500 to 3500 m ² / g, in particular from 2000 to 2500 m ² / g. The production of the synthetic fibers is known to the person skilled in the art. Common manufacturing processes are, for example, the spinning process or the production using the flashing process.

The synthetic fibers can be mixed in any ratio with the cellulose fibers of the decorative paper from, for example, birch, eucalyptus and long fiber cellulose, such as pine or spruce, and processed on all conventional paper machines. Other types of trees or gas, shrub and grain pulps are also suitable. Further details can be found in "Fibers for the papermaker" in P. Keppler Verlag KG. The pulps are obtained, for example, by means of the sulfite or sulfate production process. The pulps can optionally be bleached by different processes known to the person skilled in the art. The cellulose fibers are each selected by area of application, the advantages and disadvantages of the individual cellulose fibers being known in the specialist world. The processing of the fibers into decorative paper is generally known. Depending on the type of fiber and the fiber content used, slight changes in paper production are necessary, for example in the fiber mixture, When drying the decorative paper, the temperature should advantageously not exceed a range from 50 to 150 ° C. Temperatures of over 120 ° C. can lead to reduced sheet thickness r Common finishing processes are followed, such as smoothing, gluing, embossing, printing (e.g. gravure, flexo or digital printing), impregnation, shaping and / or painting.

The decorative papers used according to the invention have a Bendtsen porosity of 300 to 2000 ml / min, in particular 400 to 1200 ml / min, and thus have very good impregnability. The porosity is adjusted according to the impregnation requirements. The wet strength is advantageously 6 N to 40 N. The opacity of the decorative paper is generally 0 to 100%, in particular 60 to 100%. The decorative paper usually has a weight per unit area of 40 to 300 g / m ² , in particular 80 to 200 g / m ² . The color impression ranges between white and black, bright colors in numerous shades can be realized.

The decorative papers can have smoothness on one or both sides, with smoothness on one side being preferred.

The decorative paper, which contains 5 to 90% by weight, based on the total fiber content, of fibers made of synthetic polymers, advantageously contains 95 to 10% by weight of cellulose. The cellulose is advantageously chemically unchanged. Basically, the cellulose can be used bleached or unbleached. The use of bleached cellulose is preferred. Eucalyptus globulus, Nordic birch and Long fiber. The decorative paper preferably contains 10 to 60% by weight, based on the total fiber content, fibers of synthetic polymers and 90 to 40% by weight of cellulose. In particular, the decorative paper contains 10 to 40% by weight, based on the total fiber content, fibers of synthetic polymers and 90 to 60% by weight of cellulose. The decorative paper particularly preferably contains 10 to 40% by weight, based on the total fiber content, of fibers made of polyamide, polyester, polypropylene and / or polyethylene.

In addition to the cellulose fibers and the fibers made of synthetic polymer, the decorative paper used according to the invention can contain other usual components known to the person skilled in the art, such as, for example, secondary fibers, fillers or pigments. The inorganic or organic pigments control i.a. opacity generation, color imparting, printability and thickness increase. White or color pigments can advantageously be present in the formulation as compounds in the form of oxides, silicates, carbonates, sulfates or carbon blacks.

Preferred inorganic pigments which can serve as colorants in the decorative paper used according to the invention are, for example, iron oxides, iron cyanoferrates, sodium aluminum silicates and / or titanium dioxides. The titanium dioxides are produced, for example, by the chloride or the sulfate process. Depending on the area of application, these can be modified, for example coated or coated. The modification can be carried out with various materials, for example with phosphorus, phosphorus pentoxide, aluminum, zirconium, aluminum oxide and / or silicon dioxide.

Preferred organic pigments which can serve as colorants in the decorative paper used according to the invention are, for example, those from the class of the monoazo pigments (for example products which are derived from acetoessigarylide derivatives or from .beta.-naphthol derivatives), lacquered monoazo dyes (for example B. lacquered ß-oxynaphthoic acid dyes), disazo pigments, condensed disazo pigments, isoindoline derivatives, derivatives of naphthalene or perylenetetracarboxylic acid, anthracinone pigments, thioindigo derivatives, azomethine derivatives, quinacridones, dioxazines, pyrazole-phthalocyanine verolone z - methane dyes).

The total pigment content in the base paper produced is advantageously between 0 and 40% by weight, based on the total paper, in particular between 5 and 20% by weight. When using pigments, 5 to 10% by weight of pigments based on silicates and up to 20% by weight, preferably 0 to 15% by weight, of titanium dioxide and iron oxides are used.

The wet-strength decorative papers can usually be reprocessed normally without any problems using known standard processes. Crosslinkable aminoplastic resins are all resins known to the person skilled in the art, in particular melamine-urea-formaldehyde and melamine-formaldehyde resin or mixtures thereof. These resins can be partially or completely etherified with alcohols, preferably C to C ₄ alcohols, in particular methanol. Etherified and non-etherified melamine-urea-formaldehyde and melamine-formaldehyde resins or mixtures thereof are preferably used, in particular etherified and / or non-etherified melamine-formaldehyde resins, particularly preferably non-etherified melamine-formaldehyde resins.

Resin mixtures which contain non-etherified melamine-formaldehyde condensate (s), optionally etherified melamine-formaldehyde condensate (s) and polymer dispersion (s) are particularly preferred.

Resin mixtures which are particularly suitable are those which

(i) 5 to 90% by weight, in particular 20 to 80% by weight of one or more unetherified melamine-formaldehyde condensation products, (ii) 0 to 80% by weight, in particular 0 to 50% by weight of one or more etherified melamine-formaldehyde condensation products, and (iii) 10 to 95% by weight, in particular 20 to 80% by weight, of one or more polymer dispersions. The amounts of components (i), (ii) and (iii) add up to 100% by weight and relate to the liquid resin mixture.

Auxiliaries and additives can also be added to the melamine resin mixture, for example 0.1 to 50% by weight, preferably 0.2 to 30% by weight, in particular 0.5 to 20% by weight of urea, caprolactam, phenyl diglycol, butanediol and / or sucrose based on 100 wt .-% of the mixture (i) to (iii). It can also contain conventional additives such as wetting agents, curing agents and catalysts.

In addition, the resin mixture can contain one or more of the following components in a total amount of 0 to 5% by weight, based on the resin mixture: anionic surfactants (sodium, potassium and / or ammonium salts of fatty acid and sulphonic acid; alkali metal salts of C ₁₂ - bis C ₁₆ alkyl sulfates; ethoxylated, sulfated and / or sulfonated fatty alcohols; alkylphenols; sulfodicarboxylated esters; polyglycol ether sulfates), non-ionic surfactants (ethoxylated fatty alcohols and alkylphenols with 2 to 150 ethylene oxide units per molecule), cationic surfactants (ammonium, Phosphonium and / or sulfonium compounds with a hydrophobic structural element that contains at least one long aliphatic hydrocarbon chain), starch, polyethylene glycol and / or poly (vinyl alcohol).

The following is to be stated in detail regarding the resin components: Melamine-formaldehyde condensation products are used as resin component (i). The production of the resin component (i) is generally known. First, for example, 1 mol of melamine is condensed with 1.4 to 2 mol of formaldehyde at pH values from 7 to 9 and at temperatures from 40 to 100 ° C. until the appropriate degree of condensation is reached. The molar ratio of melamine to formaldehyde is advantageously 1: 1.15 to 1: 1.9, preferably 1: 1.4 to 1: 1.6.

In the resin component (ii) melamine-formaldehyde condensation products with C to C alkanols such as methanol, ethanol, propanol and / or butanol or glycols, such as e.g. Ethylene glycol, diethylene glycol, propylene glycol and / or dipropylene glycol, etherified. Methanol and buthanol are preferred. The production of the resin component (ii) is generally known. The melamine-formaldehyde condensation product is mixed, for example, with 20 to 30 mol of methanol and etherified at pH values from 1 to 5 and temperatures from 40 to 80 ° C. The condensation conditions depend on the water dilutability desired for the resin, which is at least 1: 6. After the condensation, the melamine resins are freed from excess alcohol and formaldehyde by distillation. Any remaining formaldehyde is reacted with the addition of urea at temperatures from room temperature to 90 ° C, preferably 60 to 70 ° C. The molar ratio of melamine to formaldehyde to ether group is advantageously 1: 1.2: 1 to 1: 6: 6, preferably 1: 2.5: 2 to 1: 5: 4.5.

As resin component (iii), copolymer dispersions are used, the copolymers of which preferably contain carboxyl, hydroxyl, amide, glycidyl, carbonyl, N-methylol, N-alkoxymethyl, amino and / or hydrazo groups. The above-mentioned functional groups in the copolymer are obtained in the usual way by polymerizing in corresponding monomers which carry these functional groups. The copolymers generally contain the abovementioned functional groups in amounts such that they can contain 0.1 to 50% by weight, preferably 0.3 to 20, based on the copolymer, of these monomers having functional groups in copolymerized form.

The main monomers of the comonomers having the abovementioned groups are the customary olefinically unsaturated monomers copolymerizable therewith, for example C to C ₁₂ -alkyl esters of acrylic acid and methacrylic acid, preferably C to C ₈ -alkyl esters, for example methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, Propyl methacrylate, butyl acrylate, butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate and lauryl methacrylate; Vinyl esters of C ₂ to C ₄ carboxylic acids, for example vinyl acetate and vinyl propionate, C to C dialkyl esters of maleic acid and fumaric acid, vinyl aromatics such as styrene, α-methylstyrene, vinyltoluene; Acrylonitrile, methacrylonitrile, acrylamide, methacrylamide and vinyl ether with 3 to 10 carbon atoms, vinyl halides such as vinyl chloride and vinylidene chloride; polyolefinically unsaturated Compounds such as butadiene and isoprene and mixtures of the above-mentioned monomers insofar as they are copolymerizable with one another.

To prepare the resin mixture, the pH of the polymer dispersion is usually adjusted to 7.5 to 10 before the addition of the other components.

The aminoplast resins thus obtained generally have solids contents of 40 to 70% by weight. The solids content here is the dry residue, which is determined by drying 1 g of aqueous resin in a drying cabinet at 120 ° C. for two hours. The viscosity of the aqueous resins are in the range from 10 to 200 mPas, preferably between 30 and 150 mPas (20 ° C.).

The invention further relates to aminoplast resin films or films containing decorative papers impregnated with crosslinkable aminoplastic resin and containing 5 to 90% by weight, based on the total fiber content, of fibers made of synthetic polymers.

To produce them, the decorative paper already described, which contains 5 to 90% by weight, based on the total fiber content, of fibers made of synthetic polymers, is impregnated with the amino resins in a manner known per se.

The aminoplast resins are used in the form of a 40 to 70 percent by weight aqueous solution, to which a hardener is usually added.

Bronstedt acids such as organic sulfonic acids and carboxylic acids and their anhydrides, e.g. Maleic acid, maleic anhydride and formic acid, ammonium compounds, e.g. Ammonium sulfate, ammonium sulfite, ammonium nitrate, ethanolammonium chloride, dimethylethanolammonium sulfite and hardener combinations such as morpholine / p-toluenesulfonic acid.

The hardeners can be added in amounts of 0 to 2.5% by weight, based on the aqueous impregnating resin. It is known to the person skilled in the art that the hardener metering can be adapted to the respective application requirements, the reactivity of the impregnating resin / hardener mixtures, for. B. can be adjusted accordingly by measuring the turbidity times and gelling times.

Auxiliaries such as wetting agents can also be added to the impregnation liquors. Suitable wetting agents are, for example, ethoxylated fatty alcohols or alkylphenol ethoxylates, which can be added in amounts of 0 to 1% by weight, based on the resin solution.

The way in which the impregnation liquors are processed into melamine resin impregnates and how the wood materials are coated with these impregnates is known to the person skilled in the art. The decorative paper used according to the invention can be processed to the same extent as commercially available decorative paper known for the impregnation with aminoplast resins.

The impregnation is usually carried out in such a way that the decorative paper is saturated with the aminoplast resin solution. For example, decorative papers with a basis weight in the range from 60 to 200 g / m ^{2 are} impregnated with 120 to 150% by weight, based on the paper weight of the impregnation liquor, at room temperature. The impregnated paper is then dried to a residual moisture content of approximately 5 to 10% by weight. The usual impregnation systems are suitable for impregnation, which apply the desired amount of resin to and into the papers in the so-called one- or two-stage process. The advantage of the two-stage process is that, if necessary, different aminoplast resins can be used for pre- and post-impregnation.

The aminoplast films or films produced in this way are then shaped hot or cold. The foils or films are advantageously pressed with the substrate at elevated temperatures of, for example, 150 to 210 ° C. and / or elevated pressures of, for example, 15 to 30 bar during a pressing time of, for example, 10 to 60 s.

Adhesion during coating is advantageously carried out by the aminoplast resin, i.e. self-adhesive aminoplast resin films are advantageously used for 3D deformation. In some applications, however, the use of non-self-adhesive aminoplast resin films can also be advantageous, in which case commercially available adhesives or other adhesive carriers are used. In some applications, re-gluing can also be advantageous.

The substrate, in particular wood-based material or other mold carriers such as, for example, preformed plastics or metal sheets, and the decorative paper can be deformed together, for example. This is advantageously done by pressing in one

Mold carrier press (in-mold press). However, a substrate with a three-dimensional structure and a decorative paper of this contour or without a contour can also be deformed accordingly. The three-dimensional deformation is advantageously carried out in a membrane press or, if appropriate, in a press, the press plate of which corresponds to the negative shape of the three-dimensional carrier material.

For example, in such a membrane press, the upper and / or lower and / or lateral sides of the press form consist of a membrane which can be pressurized by air, nitrogen or liquid which may be heated (see WO 00/53667 on pages 16 to 18 ). Such a membrane press advantageously includes a lower and an upper press table, an elastic membrane which can be pressed onto a substrate covered with aminoplast resin films or films and thus to be coated and which forms a pressure-tight chamber with a press table, channels for inlet and outlet of a fluid acting on the membrane and a press control.

The term “compressible membrane” means membranes that can be lowered as well as raised or pressed from the side.

For the three-dimensional shaping, a membrane press is advantageously used, which has two storage containers for two fluids of different temperatures, which are provided with working valves which can be opened and closed by the press control. The membrane press advantageously has a conveying device for the fluids. The membrane press preferably has separate inlets and outlets for each fluid.

The fact that the press preferably has two storage containers, which contain fluids of different temperatures, which can act alternately on the membrane via working valves and a conveying device, enables a heating-cooling alternating press to be realized, with which a workpiece can first be pressed hot and then cold without having to be transported from one press to another press, which also has the significant advantage that the workpiece remains fixed in the press, so that the material to be coated does not detach and the coated workpiece does not bulge or warp can, since it remains fixed in the membrane press until a minimum temperature is reached.

Each storage container advantageously has a compressed air valve and a vent valve. Depending on the individual process steps, the contents of the storage containers can be subjected to pressure-variable heights. Heating devices or cooling devices for the fluid are advantageously arranged in the storage containers, which can also be circulated during a pressing process if there is an increased heat or waste heat requirement.

A liquid, such as water or thermal oil, which has a high heat capacity, is preferably used as the fluid, so that the required amounts of heat can be supplied and removed by the fluids alone, without the press tables themselves having to be heated or cooled. They can even be equipped with insulation material on their surfaces facing the press room, so that no heat losses occur via the press tables. It is also advantageous that the storage containers, which have compressed air and venting valves, can be pressurized or depressurized as a function of the process steps that can be carried out with the membrane press, so that a change of the liquids is carried out more quickly can be made available or the pressing pressure can be made available at any height or optimized for the workpieces and aminoplast resin films or films.

As a conveying device for the liquids, the membrane press advantageously has a second elastic membrane beneath the first membrane, which forms a second pressure-tight chamber with the first membrane via a second frame, which chamber, depending on the individual process steps, has inlets or outlets with a Working fluid is acted upon. It is particularly advantageous here to use air as the working fluid, with which the liquid located in the first chamber between the press table and membrane can be pushed back into the storage container when the second chamber is pressurized. Such a conveying device for liquids is extremely simple, effective and low-maintenance with minimal technical effort.

The membrane press described can also be used advantageously for three-dimensional shaping if flexible aminoplast resin films or films (see

DE 103 01 901) of, for example, aminoplast resins made from non-etherified melamine-formaldehyde condensate (s), optionally etherified melamine-formaldehyde condensate (s) and polymer dispersion (s), as described above, impregnated in the booth absorbent cellulose-containing fibrous materials, fabrics or decorative papers known in the art, as described for example in DE 200 19 180, can be used.

The coating is preferably carried out over a large area in a single work step. Furniture parts with low mechanical stress are advantageously coated with a single-layer decorative film. Only a single decorative paper is particularly preferably used for the structure to be coated.

Wood substrates, such as wood fibers or chipboard, MDF or HDF boards, are particularly preferred as substrates.

The aminoplast resin films or films according to the invention are characterized in particular by the fact that the aminoplast resin films or films are pressed onto substrates with a three-dimensionally structured surface made of different materials such as wood, plastics, fiber composites or in particular wood-based materials, e.g. Plywood, fibreboard and especially chipboard surfaces that are crack-resistant, shiny and insensitive to water vapor. Furthermore, the aminoplast resin films according to the invention are particularly well suited for the full or partial sheathing of moldings. In particular, the surfaces have a high color brilliance.

Typical areas of application for the aminoplast resin films or films according to the invention are, as already described, furniture parts such as kitchen fronts, panels, Picture frames, door frames, doors, table tops, window sills, fronts or accessories.

Examples

A) Production of the decorative paper 1 A paper was made from a mixture of eucalyptus (20% by weight), birch (80% by weight), polyamide and polyester fibers (each 15% by weight based on the cellulose) a fourdrinier machine. Titanium dioxide (10% by weight based on the total fibers) and silicate (5% by weight based on the total fibers) were added to this fiber mixture. The paper had a basis weight of 131 g / m ² and showed porosity Bendsten of 990 ml / min.

B1) Resin System 1 Component 1: A mixture of 730 g 40% by weight aqueous formaldehyde and 334 g water was heated to 30 ° C. The pH of the mixture was adjusted to approximately 9.5 with 25% by weight aqueous sodium hydroxide solution. Then 790 g of melamine were added. The reaction mixture was then heated to 100 ° C., the pH slowly dropping. It was for about 60 min. stirred at a pH of 8.6 to 8.8. As soon as a sample of the reaction mixture had a cloud temperature of 50 ° C., the reaction mixture was cooled to room temperature.

Component 2: 8.4 g of sodium peroxodisulfate and 600 g of water were placed in a reaction vessel and heated to 80.degree. While maintaining the temperature, feed 1 was continuously added over an hour. Feed 1 was prepared from 387 g of deionized water, 151.2 g of 2-hydroxyethymethacrylate and 58.8 g of acrylic acid. After the start of feed 1, feed 2 was added over a further 45 minutes. Feed 2 consisted of a solution of 81 g of deionized water and 2.1 g of sodium peroxodisulfate. After the end of feed 1, the temperature was maintained for one hour and then feed 3 was added at 80 ° C. within 1.5 hours and feed 4 within 2 hours. Feed 3 consisted of an aqueous monomer emulsion composed of 410 g of deionized water, 4.7 g of a 45% by weight aqueous solution of the surfactant corresponding to Dowfax 2A1, 378 g of styrene and 436.8 g of n-butyl acrylate. Feed 4 consisted of a solution of 410 g of deionized water and 10.5 g of sodium peroxodisulfate. After feed 4 had ended, the mixture was left to react at 80 ° C. for one hour. The mixture was then cooled to room temperature, 134.4 g of a 25% by weight aqueous sodium hydroxide solution were added and the mixture was filtered through a 200 μm sieve. The solids content of the dispersion obtained was 34.4% by weight and the pH was 7.1. 70% by weight of a component 1 solution was added to 30% by weight of a component 2 solution with stirring. The resin mixture had a viscosity of 65 mPas and a dry content of 51.2% by weight.

B2) Resin system 2

A mixture of 812 g 40% by weight aqueous formaldehyde and 358 g water was heated to 30 ° C. The pH of the mixture was adjusted to about 9 using 25% by weight aqueous sodium hydroxide solution. Then 821 g of melamine were added. The mixture was then heated to 100 ° C. and then condensed to a cloud point of 50 ° C. When the cloud point was reached, the reaction mixture was cooled immediately. A pH of about 9.2 was set with 25% by weight aqueous sodium hydroxide solution. The resin solution had a viscosity of 45 mPas (20 ° C).

C) Impregnation With the resin mixture from Example 1 and the resin from Example 2, after adding about 0.5% by weight of hardener (for example hardener 529 liquid from BASF AG), decorative paper from Example 1 and standard decorative paper were impregnated and dried that the decorative papers had a solid content in the full impregnation of 120 to 130% and a residual moisture content of 6 to 10%.

D) 3D coating

The melamine resin film obtained was pressed onto an MDF (Medium Density Fiber) plate with a diameter of 16.5 cm including a 3D structure. 3D structures are contours with round and straight surfaces and / or edges with a defined angle. The pressing process took place in a laboratory press at 150 to 160 ° C under a force of 45 kN and in a time of 30-60 s.

E) characterization

E1) deformability

The deformability and the adhesion of the melamine resin film to the MDF board including a 3D structure was assessed. In the case of good deformability, the coating should lie completely against the structure and adhere firmly to it without tearing, breaking or creasing. Evaluation:

0 = free of cracks or wrinkles

1 = free of cracks, isolated wrinkles

2 = isolated cracking, slight wrinkling

3 = slight cracking, moderate wrinkling 4 = moderate cracking, severe wrinkling

5 = severe cracking, very severe wrinkling

6 = broken and destroyed surface

E2) Characterization of the surface

The melamine resin film obtained was pressed onto a smooth MDF board at 160-165 ° C. under a pressure of 2.5 N / mm ² and over a period of 110 s. The following tests were carried out:

E2.1) hardening

The quality of the curing was determined by exposure to the smooth coated MDF board for 16 hours of 0.2N hydrochloric acid stained with 0.004% by weight rhodamine B solution. With good hardening, the surface is not attacked by the acid. The strength of the attack can be judged from the strength of the red color. Evaluation:

0 = no attack

1 = weak pink color

2 = clear red color

3 = strong red color 4 = strong red color with slight surface swelling

5 = strong red color with strong surface swelling

6 = destroyed surface

E2.2) Closeness The closeness or porosity of the coated surface is used to assess the sensitivity to dirt. The surface to be tested was rubbed with black shoe polish and then cleaned again with a rag. The shoe polish remaining in the pores enables the closed surfaces to be assessed. The surface closeness is assessed in the following stages:

0 = non-porous

1 = isolated pores

2 = few pores

3 = frequent pores = many vacancies

5 = many vacancies

6 = no unity The results are presented in Table 1.

Table 1

commercial white decorative paper

Claims

claims

1. Process for the production of partially or completely coated substrates with a three-dimensionally structured surface, characterized in that a decorative paper which contains 5 to 90% by weight, based on the total fiber content, of fibers made of synthetic polymers, impregnated with a crosslinkable aminoplastic resin , applied to the substrate and three-dimensionally deformed.

2. The method according to claim 1, characterized in that the synthetic polymers used are polyamide, polyimide, polyurethane, polypropylene, polyethylene, polyester, polyacrynitrile and / or polyvinyl alcohol.

3. The method according to claim 1 or 2, characterized in that the fibers made of synthetic polymers have a length of 0.5 to 20 mm.

4. The method according to claims 1 to 3, characterized in that the fibers made of synthetic polymers have a diameter of 5 to 30 microns.

5. The method according to claims 1 to 4, characterized in that cellulose is used as the base of the decorative paper.

6. The method according to claims 1 to 5, characterized in that the decorative paper contains 10 to 60 wt .-% fibers of synthetic polymers and 40 to 90 wt .-% cellulose.

7. The method according to claims 1 to 6, characterized in that melamine-formaldehyde resins are used as the aminoplastic resin.

8. The method according to claims 1 to 6, characterized in that a resin mixture of melamine-formaldehyde condensation product (s), etherified melamine-formaldehyde condensation product (s) and polymer dispersion (s) is used as the aminoplastic resin.

9. The method according to claims 1 to 8, characterized in that wood, chipboard, MDF or HDF boards are used as substrates.

10. The method according to claims 1 to 9, characterized in that the three-dimensional deformation is carried out in a membrane press.

11. The method according to claim 10, characterized in that the membrane press has a lower and an upper press table, an elastic membrane which can be pressed onto a substrate covered with aminoplast resin films or films and thus to be coated and which forms a pressure-tight chamber with a press table for inlet and outlet of a fluid acting on the membrane and a press control.

12. Aminoplast resin film or film containing decorative paper impregnated with crosslinkable aminoplastic resin and containing 5 to 90% by weight, based on the total fiber content, of fibers made of synthetic polymers.

13. Use of a decorative paper which contains 5 to 90% by weight, based on the total fiber content, of fibers made of synthetic polymers for the production of aminoplast resin films or films.

14. Use of a decorative paper according to claim 13, wherein the synthetic polymers used are polyamide, polyimide, polyurethane, polypropylene, polyethylene, polyester, polyacrynitrile or polyvinyl alcohol.

15. Use of a decorative paper according to claim 13 or 14, wherein the decorative paper is impregnated with a resin mixture of melamine-formaldehyde condensation product (s) and polymer dispersion (s).

16. Use of an aminoplast resin film or film containing a decorative paper which contains 5 to 90% by weight, based on the total fiber content, of fibers made of synthetic polymers for the coating of substrates and / or moldings.

17. Use according to claim 16 for the coating of substrates with three-dimensionally structured surfaces.