EP2129519B1 - Laminates comprising metal oxide nanoparticles - Google Patents

Abstract

The invention relates to laminates, which in the overlay preferably comprise metal oxide nanoparticles having a high percentage of α-Al2O3. These nanoparticles are preferably treated with a coating agent or stabilizer.

Description

Laminate is a multi-layer, thermosetting plastic, which is produced by pressing and gluing at least two layers of the same or different materials. Combination can complement the properties of the individual materials.

The most common laminates are approx. 0.5 to 1.2 mm thick and are usually applied to a carrier material (eg HDF or chipboard) in further processing with a special adhesive. The most common type of application for such laminate coatings is the laminate floor and kitchen countertops. It is also possible to easily produce laminates with thicknesses of 2 to 20 cm. Such referred to as compact laminates products are self-supporting with increasing thickness and find z. B. in the interior but also in outdoor use as facade or balcony cladding use. Laminate has many positive characteristics: the surface is dense, impact and abrasion resistant. It can be provided with various structures and can withstand high temperatures for a short time without being damaged. The surface is easy to care for and clean, heat and light resistant and odorless and insensitive to alcohol or organic solvents and the effect of water vapor.

For low surface load applications (eg kitchen fronts), the direct-coated support plates (two melamine resin-impregnated papers or a so-called finishing film are pressed directly into the substrate) are used. Direct-coated materials are less resilient than HPL or CPL coated materials due to the lower thickness of the surface coating. Today, the term laminate is often used as a synonym for laminate flooring. Laminate flooring is the combination of a HPL (high pressure laminate) or CPL (continuous pressure laminate) layer, which is adhered to a carrier material (usually an HDF board).

To obtain a laminate plate, several resin-impregnated papers are pressed together under pressure and temperature. The resins used are melamine-formaldehyde, phenol-formaldehyde, urea-formaldehyde resins and combinations of these substances. For a high-quality decorative laminate, as z. B. is used in laminate floors, the following layers are used: The core consists of several phenol resin impregnated papers, above is the melamine resin impregnated decorative layer. At the top, a so-called overlay is pressed, which consists of two transparent melamine-impregnated papers, between which a corundum layer of coarse corundum (> 20 microns) may be included for reasons of stability. It is also the use of corundum filled overlays common. On the bottom of a counter-pull is used, which reduces bending of the finished material. The coarse corundum has the task to protect the decor against abrasion and brings the required stability. In multilayer construction is usually still working with a finishing layer, which is not equipped with corundum to protect the press plates and avoiding roughness of the effective area. The final overlay is therefore exposed in unprotected form daily scratchings.

WO 02/24446 describes laminates containing metal oxide particles to improve rub resistance. These metal oxide particles, which are prepared by the sol-gel method, have a particle diameter of 5 to 70 microns and are therefore not nanoparticles.

It has now been found that one can improve the scratch resistance of the final overlay by incorporating nanocorundum.

The invention relates to laminates, preferably a laminate overlay containing metal oxide nanoparticles with a high proportion of α-aluminum oxide. Preferred nanoparticles which are used according to the invention are particles having an average particle size in the range from 1 nm to 900 nm, preferably 1 to 200 nm, and consist of oxides of elements of main group 3, in particular aluminum. The proportion of α-alumina is preferably in Range 50-100%. At a content of less than 100% Al ₂ O ₃ contain the metal oxide nanoparticles in addition to the α-Al ₂ O ₃ further oxides as described below. It may also be advantageous to mix these metal oxide nanoparticles with aluminum oxide whose fineness is in the μm range, preferably <10 μm.

The nanoparticles are prepared by deagglomeration of larger agglomerates containing or consisting of these nanoparticles in the presence of a dispersant using suitable stabilizers. Such agglomerates are known per se and can be prepared, for example, by the methods described below:

Nanoparticles containing coating compositions are known, wherein the nanoparticles are prepared by sol-gel technique by hydrolytic (co) condensation of tetraethoxysilane (TEOS) with other metal alkoxides in the absence of organic and / or inorganic binders. Out DE 199 24 644 It is known that the sol-gel synthesis can also be carried out in the medium. Radiation-curing formulations are preferably used. However, all materials produced by sol-gel process are characterized by low solids contents of inorganic and organic substance, by increased amounts of the condensation product (usually alcohols), by the presence of water and by limited storage stability.

Progress is made by the high-temperature-resistant, reactive metal oxide particles produced by hydrolytic condensation of metal alkoxides on the surface of nanoscale inorganic particles in the presence of reactive binders. The temperature resistance of the reacted formulations is achieved by the heterogeneous copolymerization of reactive groups of the medium with similar reactive groups of the binder. The disadvantage here is the incompleteness of the heterogeneous copolymerization, in which not all reactive groups on the surface of the particles enter the copolymerization. Reason are mainly steric hindrance. However, it is known that the unreacted groups lead to undesired secondary reactions, which can cause discoloration, embrittlement or premature degradation. This is especially true for high temperature applications. Also in the DE 198 46 660 described method leads to non-storage stable systems due to the acidic medium in the presence of the condensation product (usually alcohols).

Also known are nanoscale surface-modified particles (Degussa Aerosil ^® R 7200), which are obtained by condensation of metal oxides with silanes in the absence of a binder and hence in the absence of strong shear forces, as they act in viscous media at stirring speeds of ≥ 10 m / s. These aerosils therefore have larger particles than the raw materials used, their opacity is significantly higher and their effectiveness is less than the effect of in WO 00/22052 described particles and the varnishes produced therefrom.

Through various chemical syntheses, which are usually precipitation reactions (hydroxide precipitation, hydrolysis of organometallic compounds) followed by calcination. Crystallization seeds are often added during the production of pure α-alumina in order to lower the transformation temperature. The sols thus obtained are dried and thereby converted into a gel. The further calcining then takes place at temperatures between 350 ° C and 650 ° C. For the conversion to α-Al ₂ O ₃ must then be annealed at temperatures around 1000 ° C. The procedures are detailed in DE 199 22 492 described.

Another way is the aerosol process. The desired molecules are obtained from chemical reactions of a Precursorgases or by rapid cooling of a supersaturated gas. The formation of the particles occurs either through collision or the constant equilibrium evaporation and condensation of molecular clusters. The newly formed particles grow by further collision with product molecules (condensation) and / or Particles (coagulation). If the coagulation rate is greater than that of the new growth or growth, agglomerates of spherical primary particles are formed.

Flame reactors represent a production variant based on this principle. Nanoparticles are formed here by the decomposition of precursor molecules in the flame at 1500 ° C.-2500 ° C. As examples, the oxidations of TiCl ₄ ; SICl ₄ and Si ₂ O (CH ₃ ) _{6 are mentioned} in methane / O ₂ flames leading to TiO ₂ and SiO ₂ particles. When using AlCl ₃ so far only the corresponding clay could be produced. Flame reactors are now used industrially for the synthesis of submicroparticles such as carbon black, pigment TiO ₂ , silica and alumina.

Small particles can also be formed from drops with the help of centrifugal force, compressed air, sound, ultrasound and other methods. The drops are then converted into powder by direct pyrolysis or by in situ reactions with other gases. As known methods, the spray and freeze drying should be mentioned. In spray pyrolysis, precursor drops are transported through a high temperature field (flame, oven), resulting in rapid evaporation of the volatile component or initiating the decomposition reaction to the desired product. The desired particles are collected in filters. As an example, the production of BaTiO ₃ from an aqueous solution of barium acetate and titanium lactate can be mentioned here.

By grinding can also be attempted to crush coarse material and thereby produce crystallites in the nano range. The best grinding results can be achieved with stirred ball mills in a wet grinding. In this case, grinding beads must be used from a material that has a higher hardness than the material to be ground. In the case of the metal oxides to be used according to the invention, however, this route is eliminated owing to the high hardness of the material.

Another way to produce corundum at low temperature is the conversion of aluminum chlorohydrate. This is also with Seed germs, preferably of fine corundum or hematite, added. To avoid crystal growth, the samples must be calcined at temperatures of around 700 ° C to a maximum of 900 ° C. The duration of the calcination is at least four hours. Disadvantage of this method is therefore the large amount of time and the residual amounts of chlorine in the alumina. The method has been described in detail in Ber. DKG 74 (1997) no. 11/12, p. 719-722 ,

From these agglomerates, the nanoparticles must be released. This is preferably done by grinding or by treatment with ultrasound. According to the invention, this deagglomeration is carried out in the presence of a solvent and a coating agent or stabilizer for modifying the surface, which is a silane or siloxane, during the milling process, saturating the resulting active and reactive surfaces by a chemical reaction or physical attachment and thus reagglomeration prevented. The nano-oxide remains as a small particle. It is also possible to add the coating agent for the modification of the surface after deagglomeration.

Preferably, in the preparation of the metal oxide nanoparticles of agglomerates, which according to the information in Ber. DKG 74 (1997) no. 11/12, p. 719-722 be prepared as described above.

The starting point here is aluminum chlorohydrate, which has the formula Al ₂ (OH) _x Cl _y , where x is a number from 2.5 to 5.5 and y is a number from 3.5 to 0.5 and the sum of x and y always 6. This aluminum chlorohydrate is mixed with crystallization seeds as an aqueous solution, then dried and then subjected to a thermal treatment (calcination).

Preference is given to starting from about 50% aqueous solutions, as they are commercially available. Such a solution is added with seed crystals that promote the formation of the α-modification of Al ₂ O ₃ . In particular, such nuclei cause a lowering of the temperature for the formation of the α-modification in the subsequent thermal treatment. As germs prefers very fine disperse corundum, diaspore or hematite. Particular preference is given to using finely divided α-Al ₂ O ₃ nuclei having an average particle size of less than 0.1 μm. In general, 2 to 3 wt .-% of germs based on the resulting alumina from.

This starting solution may additionally contain oxide formers to produce mixed oxides containing an oxide MeO. For this purpose, especially in question the chlorides of the elements of the I. and II. Main group of the Periodic Table and all other metals which form alumina metal aluminates of the spinel type, such as. As zinc, magnesium, cobalt, copper, but also other soluble or dispersible salts such as oxides, oxychlorides, carbonates or sulfates. Furthermore, compounds can be added as oxide formers that give oxides of rare earths (lanthanides) in the calcination, such as. B. salts of praseodymium, samarium, ytterbium, neodymium, lanthanum, cerium or mixtures thereof. Furthermore, it may be useful to add oxide formers which yield zikon or hafnium oxide or mixtures of oxide formers which give rare earth oxides together with an oxide former for MgO. By adding such oxide formers, in addition to the corundum lattice, further crystal lattices are formed, for example garnet, spinel or magnetoplumbite lattices. In this way, the corundum mesh is reinforced and one achieves better mechanical properties.

The amount of oxide generator is such that the finished nanoparticles preferably contain 0.01 to 50 wt .-% of the oxide Me. The oxides may be present as a separate phase in addition to the alumina or with this real mixed oxides such. As spinels, etc. form. The terms nanoparticles, nanocorundum and "mixed oxides" in the context of this invention should be understood to mean that both pure corundum and mixed corundum or real mixed oxides such. B. the spinels are meant.

This suspension of aluminum chlorohydrate, germs and optionally oxide formers is then evaporated to dryness and subjected to a thermal treatment (calcination). This calcination takes place in this suitable devices, for example in push-through, chamber, tube, rotary kiln or microwave ovens or in a fluidized bed reactor. According to a variant of the process, it is also possible to inject the aqueous suspension of aluminum chlorohydrate, germs and optionally oxide formers directly into the calcining apparatus without prior removal of the water.

The temperature for the calcination should not exceed 1100 ° C. The lower temperature limit depends on the desired yield of nanocrystalline mixed oxide, the desired residual chlorine content and the content of germs. The formation of the nanoparticles begins at about 500 ° C, but to keep the chlorine content low and the yield of nanoparticles high, but you will work preferably at 700 to 1100 ° C, especially at 1000 to 1100 ° C.

It has surprisingly been found that for the calcination 0.5 to 30 minutes, preferably 0.5 to 10, in particular 2 to 5 minutes are generally sufficient. Already after this short time under the conditions given above for the preferred temperatures, a sufficient yield of nanoparticles can be achieved. But you can also according to the information in Ber. DKG 74 (1997) no. 11/12, p. 722 4 Calcine at 700 ° C for hours or at 500 ° C for 8 hours.

The nanoparticles must be released from these agglomerates containing or entirely consisting of the desired nanoparticles in the form of crystallites. This is preferably done by grinding or by treatment with ultrasound.

To obtain nanoparticles, the agglomerates are preferably comminuted by wet grinding in a solvent, for example in an attritor mill, bead mill or stirred mill. This gives nanoparticles which have a crystallite size of less than 1 μm, preferably less than 0.2 μm. For example, after six hours of grinding, a suspension is obtained of nanoparticles with a d90 value of approximately 90 nm. Another possibility of deagglomeration is sonication. It may also be advantageous to deagglomerate the resulting agglomerates in a dissolver or similar mixing equipment used in the coating industry.

There are two possibilities for modifying the surface of these nanoparticles with coating agents, also called stabilizers, ie silanes or siloxanes. According to the first preferred variant, deagglomeration can be carried out in the presence of the coating agent, for example by adding the coating agent to the mill during milling. A second possibility consists of first destroying the agglomerates of the nanoparticles and then treating the nanoparticles, preferably in the form of a suspension in a solvent, with the coating agent.

Suitable solvents for deagglomeration are both water and conventional solvents, preferably those which are also used in the paint industry, such as, for example, C ₁ -C ₄ -alcohols, in particular methanol, ethanol or isopropanol, acetone, tetrahydrofuran, butyl acetate. If the deagglomeration is carried out in water, an inorganic or organic acid, for example HCl, HNO ₃ , formic acid or acetic acid, should be added in order to stabilize the nanoparticles formed in the aqueous suspension. The amount of acid may be 0.1 to 5 wt .-%, based on the nanoparticles. For stabilization in the alkaline region, preference is given to using mixtures of polyacrylates / ammonia and citrates. If required, the nanoparticles in which the acidic or alkaline suspensions can also be coated with further coating agents, preferably with silane or siloxane, if a modification of the particle surface by such coating agents, also called stabilizer, is desired.

Suitable coating agents here are preferably silanes or siloxanes or mixtures thereof.

In addition, suitable coating agents are all substances which can bind physically to the surface of the mixed oxides (adsorption) or which can bond to form a chemical bond to the surface of the mixed oxide particles. Since the surface of the mixed oxide particles is hydrophilic and free hydroxy groups are available, suitable coating agents are alcohols, compounds having amino, hydroxyl, carbonyl, carboxyl or mercapto functions, silanes or siloxanes. Examples of such coating compositions are polyvinyl alcohol, mono-, di- and tricarboxylic acids, amino acids, amines, waxes, surfactants, polymers such as. As polyacrylates, hydroxycarboxylic acids, organosilanes and organosiloxanes.

1. a) R [-Si (R'R")-O-]_n Si (R'R")-R"' oder cyclo-[-Si(R'R")-O-]_r Si (R'R")-O-
   worin
   R, R', R", R"'- gleich oder verschieden voneinander einen Alkylrest mit 1 - 18 C-Atomen oder einen Phenylrest oder einen Alkylphenyl- oder einen Phenylalkylrest mit 6 - 18 C-Atomen oder einen Rest der allgemeinen Formel -C_mH_2m-O)_p-C_qH_2q+1 oder einen Rest der allgemeinen Formel -C_sH_2sY oder einen Rest der allgemeinen Formel -XZ_t-1,

   n

   eine ganze Zahl mit der Bedeutung 1 ≤ n ≤ 1000, bevorzugt 1 ≤ n ≤ 100,

   m

   eine ganze Zahl 0 ≤ m ≤ 12 und

   p

   eine ganze Zahl 0 ≤ p ≤ 60 und

   q

   eine ganze Zahl 0 ≤ q ≤ 40 und

   r

   eine ganze Zahl 2 ≤ r ≤ 10 und

   s

   eine ganze Zahl 0 ≤ s ≤ 18 und

   Y

   eine reaktive Gruppe, beispielsweise α,β-ethylenisch ungesättigte Gruppen, wie (Meth)Acryloyl-, Vinyl- oder Allylgruppen, Amino-, Amido-, Ureido-, Hydroxyl-, Epoxy-, Isocyanato-, Mercapto-, Sulfonyl-, Phosphonyl-, Trialkoxylsilyl-, Alkyldialkoxysilyl-, Dialkylmonoalkoxysilyl-, Anhydrid- und/oder Carboxylgruppen, Imido-, Imino-, Sulfit-, Sulfat-, Sulfonat-, Phosphin-, Phosphit-, Phosphat-, Phosphonatgruppen und

   X

   ein t-funktionelles Oligomer mit

   t

   eine ganze Zahl 2 ≤ t ≤ 8 und

   Z

   wiederum einen Rest

   
   
           R [-Si(R'R")-O-]_n Si (R'R")-R"' oder cyclo-[-Si(R'R")-O-]_r Si (R'R")-O-
   
   darstellt, wie vorstehend definiert.
   Das t-funktionelle Oligomer X ist dabei bevorzugt ausgewählt aus:
   Oligoether, Oligoester, Oligoamid, Oligourethan, Oligoharnstoff, Oligoolefin, Oligovinylhalogenid, Oligovinylidendihalogenid, Oligoimin, Oligovinylalkohol, Ester, Acetal oder Ether von Oligovinylalkohol, Cooligomere von Maleinsäureanhydrid, Oligomere von (Meth)acrylsäure, Oligomere von (Meth)acrylsäureestern, Oligomere von (Meth)acrylsäureamiden, Oligomere von (Meth)acrylsäureimiden, Oligomere von (Meth)acrylsäurenitril, besonders bevorzugt Oligoether, Oligoester, Oligourethane.
   Beispiele für Reste von Oligoethem sind Verbindungen vom Typ -(C_aH_2a-O)_b-C_aH_2a- bzw. O-(C_aH_2a-O)_b-C_aH_2a-O mit 2 ≤ a ≤ 12 und 1 ≤ b ≤ 60, z. B. ein Diethylenglykol-, Triethylenglykol- oder Tetraethylenglykol-Rest, ein Dipropylenglykol-, Tripropylenglykol-, Tetrapropylenglykol-Rest, ein Dibutylenglykol-, Tributylenglykol- oder Tetrabutylenglykol-Rest. Beispiele für Reste von Oligoestern sind Verbindungen vom Typ -C_bH_2b-(C(CO) C_aH_2a-(CO) O-C_bH_2b-)c- bzw. -O-C_bH_2b-(C(CO) C_aH_2a-(CO) O-C_bH_2b-)_c-O- mit a und b unterschiedlich oder gleich 3 ≤ a ≤ 12, 3 ≤ b ≤ 12 und 1 ≤ c ≤ 30, z. B. ein Oligoester aus Hexandiol und Adipinsäure.
2. b) Organosilane des Typs (RO)₃Si(CH₂)_m-R'

   R =

   Alkyl, wie Methyl-, Ethyl-, Propyl-

   m =

   0,1 - 20

   R' =

   Methyl-, Phenyl, -C₄F₉; OCF₂-CHF-CF₃, -C₆F₁₃, -O-CF₂-CHF₂ -NH₂, -N₃, SCN, -CH=CH₂, -NH-CH₂-CH₂-NH₂, -N-(CH₂-CH₂-NH₂)₂ -OOC(CH₃)C = CH₂ -OCH₂-CH(O)CH₂ -NH-CO-NH-CO-(CH₂)₅ -NH-COO-CH₃, -NH-COO-CH₂-CH₃, -NH-(CH₂)₃Si(OR)₃ -S_x-(CH₂)₃)Si(OR)₃ -SH -NR'R"R"' (R' = Alkyl, Phenyl; R" = Alkyl, Phenyl; R'" = H, Alkyl, Phenyl, Benzyl, C₂H₄NR"" mit R"" = A, Alkyl und R""' = H, Alkyl).

Suitable silanes or siloxanes are compounds of the formulas

1. a) R [-Si (R'R ") - O-] _n Si (R'R") - R "'or cyclo - [-Si (R'R") - O-] _r Si (R'R ")-O-
   wherein
   R, R ', R ", R"' - equal to or different from each other, an alkyl radical having 1-18 C-atoms or a phenyl radical or an alkylphenyl or a phenylalkyl radical having 6 - 18 C-atoms or a radical of the general formula -C _m H _2m -O) _p -C _q H _{2q + 1} or a radical of the general formula -C _s H _2s Y or a radical of the general formula -XZ _t-1 ,

   n

   an integer meaning 1 ≦ n ≦ 1000, preferably 1 ≦ n ≦ 100,

   m

   an integer 0 ≤ m ≤ 12 and

   p

   an integer 0≤p≤60 and

   q

   an integer 0 ≤ q ≤ 40 and

   r

   an integer 2 ≤ r ≤ 10 and

   s

   an integer 0≤s≤18 and

   Y

   a reactive group, for example α, β-ethylenically unsaturated groups, such as (meth) acryloyl, vinyl or allyl groups, amino, amido, ureido, hydroxyl, epoxy, isocyanato, mercapto, sulfonyl, phosphonyl , Trialkoxylsilyl, alkyldialkoxysilyl, dialkylmonoalkoxysilyl, anhydride and / or carboxyl groups, imido, imino, sulfite, sulfate, sulfonate, phosphine, phosphite, phosphate, phosphonate and

   X

   a t-functional oligomer with

   t

   an integer 2 ≤ t ≤ 8 and

   Z

   turn a rest

   
   
   R [-Si (R'R ") - O-] _n Si (R'R") - R "'or cyclo - [-Si (R'R") - O-] _r Si (R'R ") -O-
   
   represents as defined above.
   The t-functional oligomer X is preferably selected from:
   Oligoether, oligoester, oligoamide, oligourethane, oligourea, oligoolefin, oligovinyl halide, oligovinylidenedihalogenide, oligoimine, oligovinyl alcohol, esters, acetal or ethers of oligovinyl alcohol, cooligomers of maleic anhydride, oligomers of (meth) acrylic acid, oligomers of (meth) acrylic acid esters, oligomers of (meth ) Acrylic acid amides, oligomers of (meth) acrylsäureimiden, oligomers of (meth) acrylonitrile, particularly preferably oligoether, oligoester, oligourethanes.
   Examples of radicals of oligoethem are compounds of the type - (C _a H _2a -O) _b -C _a H _2a - or O- (C _a H _2a -O) _b -C _a H _2a -O where 2 ≤ a ≤ 12 and 1 ≤ b ≤ 60, e.g. A diethylene glycol, triethylene glycol or tetraethylene glycol residue, a dipropylene glycol, tripropylene glycol, tetrapropylene glycol residue, a dibutylene glycol, tributylene glycol or tetrabutylene glycol residue. Examples of residues of oligoesters are compounds of the type -C _b H _2b - (C (CO) C _a H _2a - (CO) OC _b H _2b -) c- or -OC _b H _2b - (C (CO) C) _a H _2a - (CO) OC _b H _2b -) _c -O- where a and b are different or equal to 3 ≤ a ≤ 12, 3 ≤ b ≤ 12 and 1 ≤ c ≤ 30, z. B. an oligoester of hexanediol and adipic acid.
2. b) Organosilanes of the type (RO) ₃ Si (CH ₂ ) _m -R '

   R =

   Alkyl, such as methyl, ethyl, propyl

   m =

   0.1 - 20

   R '=

   Methyl, phenyl, -C ₄ F ₉ ; OCF ₂ -CHF-CF ₃ , -C ₆ F ₁₃ , -O-CF ₂ -CHF ₂ -NH ₂ , -N ₃ , SCN, -CH = CH ₂ , -NH-CH ₂ -CH ₂ -NH ₂ , -N- (CH ₂ -CH ₂ -NH ₂ ) ₂ -OOC (CH ₃ ) C = CH ₂ -OCH ₂ -CH (O) CH ₂ -NH-CO-NH-CO- (CH ₂ ) ₅ -NH -COO-CH ₃ , -NH-COO-CH ₂ -CH ₃ , -NH- (CH ₂ ) ₃ Si (OR) ₃ -S _x - (CH ₂ ) ₃ ) Si (OR) ₃ -SH-NR ' R "R"'(R' = alkyl, phenyl, R "= alkyl, phenyl, R '" = H, alkyl, phenyl, benzyl, C ₂ H ₄ NR "" with R "" = A, alkyl and R ""'= H, alkyl).

n

eine ganze Zahl 2 ≤ n ≤ 1000 ist, z. B. Polydimethylsiloxan 200^® fluid (20 cSt).

Examples of silanes of the type defined above are, for. As hexamethyldisiloxane, octamethyltrisiloxane, other homologous and isomeric compounds of the series Si _n O _n-1 (CH ₃ ) _{2n + 2} , wherein

n

an integer 2 ≤ n ≤ 1000, e.g. Polydimethylsiloxane ^200® fluid (20 cSt).

r

eine ganze Zahl 3 ≤ r ≤ 12 ist,

Hexamethyl-cyclo-trisiloxane, octamethyl-cyclo-tetrasiloxane, other homologous and isomeric compounds of the series

(Si-O) _r (CH _{3) 2 R,}

in which

r

an integer 3 ≤ r ≤ 12,

m

eine ganze Zahl 2 ≤ m ≤ 1000 ist,

bevorzugt sind die α,ω-Dihydroxypolysiloxane, z. B. Polydimethylsiloxan (OH-Endgruppen, 90-150 cST) oder Polydimethylsiloxan-co-diphenylsiloxan, (Dihydroxy-Endgruppen, 60 cST).Dihydroxytetramethydisiloxane, dihydroxyhexamethyltrisiloxane, dihydroxyoctamethyltetrasiloxane, other homologous and isomeric compounds of the series

HO - [(Si-O) _n (CH ₃ ) _2n ] -Si (CH ₃ ) ₂ -OH

or

HO - [(Si-O) _n (CH ₃ ) _2n ] - [Si-O) _m (C ₆ H ₅ ) _2m ] -Si (CH ₃ ) ₂ -OH,

in which

m

an integer 2 ≤ m ≤ 1000,

Preferably, the α, ω-dihydroxypolysiloxanes, z. Polydimethylsiloxane (OH end groups, 90-150 cSt) or polydimethylsiloxane-co-diphenylsiloxane (dihydroxy end groups, 60 cST).

n

eine ganze Zahl 2 ≤ n ≤ 1000 ist, bevorzugt sind die

α ,ω-Dihydropolysiloxane, z. B. Polydimethylsiloxan (Hydrid-Endgruppen, M_n = 580).Dihydrohexamethytrisiloxane, Dihydrooctamethyltetrasiloxan other homologous and isomeric compounds of the series

H - [(Si-O) _n (CH ₃ ) _2n ] -Si (CH ₃ ) ₂ -H,

in which

n

is an integer 2 ≦ n ≦ 1000, preferred are

α, ω-dihydropolysiloxanes, e.g. B. polydimethylsiloxane (hydride end groups, M _n = 580).

Di (hydroxypropyl) hexamethyltrisiloxane, dihydroxypropyl) octamethyltetrasiloxane, other homologous and isomeric compounds of the series HO- (CH ₂ ) _u [(Si-O) n (CH ₃ ) ₂ (CH ₂ ) _u -OH, preferred are the α, ω -Dicarbinolpolysiloxanes with 3≤u≤18, 3≤n≤1,000 or their polyether-modified successor compounds based on ethylene oxide (EO) and propylene oxide (PO) as homo- or mixed polymer HO- (EO / PO) _v - (CH ₂ ) _u [(Si-O) _t (CH ₃ ) _2t ] -Si (CH ₃ ) ₂ (CH ₂ ) _u - (EO / PO) _v -OH, preferred are α, ω-di (carbinol polyether) -polysiloxanes with 3 ≤ n ≤ 1000, 3 ≤ u ≤ 18, 1 ≤ v ≤ 50.

Instead of α, ω-OH groups are also the corresponding difunctional compounds with epoxy, isocyanato, vinyl, allyl and di (meth) acryloyl used, for. B. polydimethylsiloxane with vinyl end groups (850 - 1150 cST) or TEGORAD ^® 2500 from. Tego Chemie Service.

There are also the esterification of ethoxylated / propoxylated trisiloxanes and higher siloxanes with acrylic acid copolymers and / or maleic acid copolymers as a modifying compound in question, z. B. BYK Silclean ^® 3700 from Messrs. Byk Chemie or TEGO ^® Protect 5001 from. Tego Chemie Service GmbH.

• c) Organosilane des Typs (RO)₃Si(C_nH_2n+1) und (R)₃Si(C_nH_2n+1), wobei

  R

  ein Alkyl, wie z. B. Methyl, Ethyl-, n-Propyl-, i-Propyl, Butyl-

  n

  1 bis 20.

Instead of α, ω-OH groups are also the corresponding difunctional compounds with -NHR "" with R "" = H or alkyl used, for. For example, the well-known aminosilicone oils from Wacker, Dow Corning, Bayer, Rhodia, etc. are used, which carry randomly distributed on the polysiloxane (cyclo) alkylamino groups or (cyclo) alkylimino groups on their polymer chain.

• c) organosilanes of the type (RO) ₃ Si (C _n H _{2n + 1} ) and (R) ₃ Si (C _n H _{2n + 1} ), where

  R

  an alkyl, such as. Methyl, ethyl, n-propyl, i-propyl, butyl

  n

  1 to 20.

R

ein Alkyl, wie z. B. Methyl-, Ethyl-, n-Propyl-, i-Propyl-, Butyl-,

R'

ein Alkyl, wie z. B. Methyl-, Ethyl-, n-Propyl-, i-Propyl-, Butyl-,

R'

ein Cycloalkyl

n

eine ganze Zahl von 1-20

x+y

3

x

1 oder 2

y

1 oder 2

• d) Organosilane des Typs (RO)₃Si(CH₂)_m-R', wobei

  R

  ein Alkyl, wie z. B. Methyl-, Ethyl-, Propyl-,

  m

  eine Zahl zwischen 0,1 - 20

  R'

  Methyl-, Phenyl, -C₄F₉; OCF₂-CHF-CF₃, -C₆F₁₃, -O-CF₂-CHF₂, -NH₂, -N₃, -SCN, -CH = CH₂, -NH-CH₂-CH₂-NH₂, -N-(CH₂-CH₂-NH₂)₂, -OOC(CH₃)C = -OCH₂-CH(O)CH₂, -NH-CO-N-CO-(CH₂)₅, -NH-COO-CH₃, -NH-COO-CH₂-CH₃, -NH-(CH₂)₃Si(OR)₃, -S_x-(CH₂)₃)Si(OR)₃, -SH-NR'R"R'" (R' = Alkyl, Phenyl; R" = Alkyl, Phenyl; R"' = H, Alkyl, Phenyl, Benzyl, C₂H₄NR""R'"" mit R"" = H, Alkyl und R""' = H, Alkyl) bedeutet.

Organosilanes of the type R'x (RO) ySi (CnH2n + 1) and (RO) 3Si (CnH2n + 1), wherein

R

an alkyl, such as. Methyl, ethyl, n-propyl, i-propyl, butyl,

R '

an alkyl, such as. Methyl, ethyl, n-propyl, i-propyl, butyl,

R '

a cycloalkyl

n

an integer of 1-20

x + y

3

x

1 or 2

y

1 or 2

• d) organosilanes of the type (RO) ₃ Si (CH ₂ ) _m -R ', where

  R

  an alkyl, such as. Methyl, ethyl, propyl,

  m

  a number between 0.1 - 20

  R '

  Methyl, phenyl, -C ₄ F ₉ ; OCF ₂ -CHF-CF ₃ , -C ₆ F ₁₃ , -O-CF ₂ -CHF ₂ , -NH ₂ , -N ₃ , -SCN, -CH = CH ₂ , -NH-CH ₂ -CH ₂ -NH ₂ , -N- (CH ₂ -CH ₂ -NH ₂ ) ₂ , -OOC (CH ₃ ) C = -OCH ₂ -CH (O) CH ₂ , -NH-CO-N-CO- (CH ₂ ) ₅ , -NH-COO-CH ₃ , -NH-COO-CH ₂ -CH ₃ , -NH- (CH ₂ ) ₃ Si (OR) ₃ , -S _x - (CH ₂ ) ₃ ) Si (OR) ₃ , -SH-NR'R "R '"(R' = alkyl, phenyl, R "= alkyl, phenyl, R"'= H, alkyl, phenyl, benzyl, C ₂ H ₄ NR ""R'"" with R "" = H, alkyl and R ""'= H, alkyl).

• Triethoxysilan, Octadecyltrimethoxisilan,
• 3-(Trimethoxysilyl)-propylmethacrylate, 3-(Trimethoxysilyl)-propylacrylate,
• 3-(Trimethoxysilyl)-methylmethacrylate, 3-(Trimethoxysilyl)-methylacrylate,
• 3-(Trimethoxysilyl)-ethylmethacrylate, 3-(Trimethoxysilyl)-ethylacrylate,
• 3-(Trimethoxysilyl)-pentylmethacrylate, 3-(Trimethoxysilyl)-pentylacrylate,
• 3-(Trimethoxysilyl)-hexylmethacrylate, 3-(Trimethoxysilyl)-hexylacrylate,
• 3-(Trimethoxysilyl)-butylmethacrylate, 3-(Trimethoxysilyl)-butylacrylate,
• 3-(Trimethoxysilyl)-heptylmethacrylate, 3-(Trimethoxysilyl)-heptylacrylate,
• 3-(Trimethoxysilyl)-octylmethacrylate, 3-(Trimethoxysilyl)-octylacrylate,
• Methyltrimethoxysilane, Methyltriethoxysilane, Propyltrimethoxisilane,
• Propyltriethoxisilane, Isobutyltrimethoxisilane, Isobutyltriethoxysilane,
• Octyltrimethoxysilane, Octyltriethoxysilane, Hexadecyltrimethoxysilane,
• Phenyltrimethoxysilane, Phenyltriethoxysilane,
• Tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane,
• Tetramethoxysilane, Tetraethoxysilane, Oligomeric tetraethoxysilane (DYNASIL^® 40 Fa. Degussa), Tetra-n-propoxysilane,
• 3-Glycidyloxypropyltrimethoxysilane, 3-Glycidyloxypropyltriethoxysilane,
• 3-Methacryloxylpropyltrimethoxysilane, Vinyltrimethoxysilane, Vinyltriethoxysilane,
• 3-Mercaptopropyltrimethoxysilane,
• 3-Aminopropyltriethoxysilane, 3-Aminopropyltrimethoxysilane, 2-Aminoethyl-3-aminopropyltrimethoxysilane, Triaminofunctional propyltrimethoxysilane
• (DYNASYLAN^® TRIAMINO Fa. Degussa), N-(n-Butyl-3-aminopropyltrimethoxysilane, 3-Aminopropylmethyldiethoxysilane.

Preferred silanes are the following silanes:

• Triethoxysilane, octadecyltrimethoxysilane,
• 3- (trimethoxysilyl) propyl methacrylates, 3- (trimethoxysilyl) propyl acrylates,
• 3- (trimethoxysilyl) -methyl-methacrylates, 3- (trimethoxysilyl) -methyl-acrylates,
• 3- (trimethoxysilyl) ethyl methacrylates, 3- (trimethoxysilyl) ethyl acrylates,
• 3- (trimethoxysilyl) pentyl methacrylates, 3- (trimethoxysilyl) pentyl acrylates,
• 3- (trimethoxysilyl) -hexylmethacrylate, 3- (trimethoxysilyl) -hexylacrylate,
• 3- (trimethoxysilyl) butyl methacrylate, 3- (trimethoxysilyl) butyl acrylate,
• 3- (trimethoxysilyl) heptyl methacrylates, 3- (trimethoxysilyl) heptyl acrylates,
• 3- (trimethoxysilyl) octyl methacrylates, 3- (trimethoxysilyl) octyl acrylates,
• Methyltrimethoxysilanes, methyltriethoxysilanes, propyltrimethoxisilanes,
• Propyltriethoxysilanes, isobutyltrimethoxysilanes, isobutyltriethoxysilanes,
• Octyltrimethoxysilanes, octyltriethoxysilanes, hexadecyltrimethoxysilanes,
• Phenyltrimethoxysilanes, phenyltriethoxysilanes,
• Tridecafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane,
• Tetramethoxysilane, tetraethoxysilane, tetraethoxysilane Oligomeric (DYNASIL ^® 40 Fa. Degussa), tetra-n-propoxysilane,
• 3-glycidyloxypropyltrimethoxysilanes, 3-glycidyloxypropyltriethoxysilanes,
• 3-methacryloxypropyltrimethoxysilanes, vinyltrimethoxysilanes, vinyltriethoxysilanes,
• 3-Mercaptopropyltrimethoxysilane,
• 3-aminopropyltriethoxysilanes, 3-aminopropyltrimethoxysilanes, 2-aminoethyl-3-aminopropyltrimethoxysilanes, triaminofunctional propyltrimethoxysilanes
• (DYNASYLAN ^® triamino Fa. Degussa), N- (n-butyl-3-aminopropyltrimethoxysilane, 3-Aminopropylmethyldiethoxysilane.

The coating compositions, in particular the silanes or siloxanes, are preferably added in molar ratios of nanoparticles to silane of 1: 1 to 500: 1. The amount of solvent in the deagglomeration is generally 50 to 90 wt .-%, based on the total amount of nanoparticles and solvent.

The deagglomeration by grinding and simultaneous modification with the coating agent is preferably carried out at temperatures of 20 to 150 ° C, more preferably at 20 to 90 ° C.

If deagglomeration is carried out by grinding, the suspension is subsequently separated from the grinding beads.

After deagglomeration, the suspension can be heated to complete the reaction for up to 30 hours. Finally, the solvent is distilled off and the remaining residue is dried. It may also be advantageous to use the optionally modified mixed oxide nanoparticles in the Leave solvent and use the dispersion for other applications.

It is also possible to suspend the nanoparticles in the corresponding solvents and to carry out the reaction with the coating agent after deagglomeration in a further step.

It is also possible combinations of adsorbed substances and chemically fixed substances, such. B. use silanes. When using aminosilanes, the coated nanoparticles can be reacted with the coating resins and thus chemically fixed.

The nanoparticles thus produced, optionally modified on the surface, are converted into coating compositions such as, for example, formaldehyde melamine; Urea formaldehyde; Formaldehyde-phenol and combinations of these resins incorporated as they are common in the production of laminate boards. This addition of the nanoparticles in the production of laminates is preferably carried out such that there is a dispersion of the nanoparticles in the aqueous phase to the impregnating resins for the production of the laminates and then the laminates finished in a conventional manner.

It is preferred here that the nanoparticles are incorporated in the so-called overlay, especially in the final overlay of laminate plates.

The coating compositions of the invention may also contain other additives, such as are usual in laminate boards, for example, reactive diluents, solvents and co-solvents, waxes, matting agents, lubricants, defoamers, deaerators, leveling agents, thixotropic agents, thickeners, inorganic and organic pigments, fillers, adhesion promoters, Corrosion inhibitors, anticorrosive pigments, UV stabilizers, HALS compounds, free-radical scavengers, antistatics, wetting agents and dispersants and / or the catalysts required depending on the type of curing, cocatalysts, initiators, free-radical initiators, photoinitiators, Photosensitizers, etc. Other additives also include polyethylene glycol and other water retention agents, PE waxes, PTFE waxes, PP waxes, amide waxes, FT paraffins, montan waxes, grafted waxes, natural waxes, macro- and microcrystalline paraffins, polar polyolefin waxes, sorbitan esters, Polyamides, polyolefins, PTFE, wetting agents or silicates in question.

The subject according to the invention is intended to be explained in more detail with reference to the following examples, without restricting the possible variety.

Examples Example 1: (comparison)

A 50% aqueous solution of aluminum chlorohydrate was added with magnesium chloride so that after calcination the ratio of alumina to magnesium oxide was 99.5: 0.5%. In addition, 2% of nuclei were added to the solution to a suspension of fines. After the solution has been homogenized by stirring, the drying is carried out in a rotary evaporator. The solid aluminum chlorohydrate magnesium chloride mixture was crushed in a mortar to form a coarse powder.

The powder was calcined in a rotary kiln at 1050 ° C. The contact time in the hot zone was a maximum of 5 min. A white powder was obtained whose grain distribution corresponded to the feed material.

An X-ray structure analysis shows that predominantly α-alumina is present.

The images of the SEM image taken (scanning electron microscope) showed crystallites in the range 10 - 80 nm (estimate from SEM image), which are present as agglomerates. The residual chlorine content was only a few ppm.

In a further step, 100 g of this magnesium oxide-doped corundum powder were suspended in 100 g of water. The suspension was 1 g of ammonium acrylate polymer (Dispex N ^®, Ciba) was added and a vertical stirred ball mill from. Netzsch (type PE 075). The grinding beads used consisted of zirconium oxide (stabilized with yttrium) and had a size of 0.3 mm. After three hours, the suspension was separated from the milling beads.

Example 2:

A 50% aqueous solution of aluminum chlorohydrate was added with magnesium chloride so that after calcination the ratio of alumina to magnesium oxide was 99.5: 0.5%. In addition, 2% of nuclei were added to the solution to a suspension of fines. After the solution has been homogenized by stirring, the drying is carried out in a rotary evaporator. The solid aluminum chlorohydrate magnesium chloride mixture was crushed in a mortar to form a coarse powder.

The powder was calcined in a rotary kiln at 1050 ° C. The contact time in the hot zone was a maximum of 5 min. A white powder was obtained whose grain distribution corresponded to the feed material.

An X-ray structure analysis shows that predominantly α-alumina is present.

The images of the SEM image taken (scanning electron microscope) showed crystallites in the range 10 - 80 nm (estimate from SEM image), which are present as agglomerates. The residual chlorine content was only a few ppm.

In a further step, 100 g of this magnesium oxide-doped corundum powder were suspended in 100 g of water. 1 g of ammonium acrylate polymer (Dispex N, Ciba) and 0.5 g of trimethoxyaminopropylsilane (Dynasilan Ammo) were added to the suspension and fed to a vertical stirred ball mill from Netzsch (type PE 075). The grinding beads used consisted of zirconium oxide (stabilized with yttrium) and had a size of 0.3 mm. After three hours, the suspension was separated from the milling beads.

Example 3:

A 50% aqueous solution of aluminum chlorohydrate was added with zinc chloride such that after calcination the ratio of alumina to zinc oxide is 50:50. After the solution has been homogenized by stirring, the drying is carried out in a rotary evaporator. The solid aluminum chlorohydrate zinc chloride mixture was crushed in a mortar to form a coarse powder.

The powder was calcined in a rotary kiln at 850 ° C. The contact time in the hot zone was a maximum of 5 min. A white powder was obtained whose grain distribution corresponded to the feed material.

An X-ray structure analysis showed that it is zinc spinel. The residual chlorine content is below 100 ppm. The images of the high-resolution SEM (scanning electron microscopy) show crystallites <10 nm, which are present in agglomerated form.

In a further step, 40 g of zinc spinel were suspended in 160 g of water. The suspension was deagglomerated in a vertical stirred ball mill from Netzsch (type PE 075). The grinding beads used consisted of zirconium oxide (stabilized with yttrium) and had a size of 0.3 mm. During the milling, 0.5 g of ammonium acrylate (Dispex N, Ciba) and 0.3 g of trimethoxyaminopropylsilane (Dynasilan Ammo) were added throughout the duration of the deagglomeration. After 6 hours, the suspension was separated from the grinding beads and characterized with the aid of an analytical disk centrifuge from Brookhaven with regard to particle size distribution. A d90 of 55 nm was found.

Example 4:

500 g of a 50% aqueous solution of aluminum chlorohydrate was admixed with a suspension of corundum micro-organisms (2% based on Al 2 O 3), with 5.2 g of yttrium nitrate and with 4 g of lanthanum nitrate. After the solution has been homogenized by stirring, the drying is carried out in a rotary evaporator. The solid aluminum chlorohydrate salt mixture was crushed in a mortar to form a coarse powder.

The powder was calcined in a muffle furnace at 1100 ° C. The contact time was about 30 minutes. A white powder was obtained whose grain distribution corresponded to the feed material.

An X-ray structure analysis showed that it is corundum interspersed with the phases of the corresponding mixed oxides. The images of the high-resolution SEM (scanning electron microscopy) show plate-like growths of the corundum crystallites present in excess.

In a further step, 40 g of the foreign phases reinforced corundum were suspended in 160 g of water. The suspension was deagglomerated in a vertical stirred ball mill from Netzsch (type PE 075). The grinding beads used consisted of zirconium oxide (stabilized with yttrium) and had a size of 0.3 mm. During the milling, 0.5 g of ammonium acrylate (Dispex N, Ciba) and 0.3 g of trimethoxyaminopropylsilane (Dynasilan Ammo) were added throughout the duration of the deagglomeration. After 6 hours, the suspension was separated from the grinding beads and characterized with the aid of an analytical disk centrifuge from Brookhaven with regard to particle size distribution. A d90 of 55 nm was found.

applications

The coated nanoparticles from Examples 1 to 3 were mixed with impregnating resins (dissolvers) and the mixtures were used to coat printed decorative paper. The melamine resin Madurit ^® MW 550 (Ineos Melamines) was used for the tests. After the impregnation had been dried, the lamination of the decorative papers on support plates was carried out in a hot press at 150 ° C. and a pressure of 200 bar. The pressing time was 4 min.

The finished pieces of laminate (40 cm * 40 cm) were checked for scratch resistance using a diamond stylus (Eriksentest). The scratch resistance is the better the higher the contact force of the diamond stylus.

The following measured values were determined: reference pattern reference pattern + 3% nanoparticles (Example 1) comparison + 3% nanoparticles (Example 2) + 3% nanoparticles (Example 3) + 3% nanoparticles (Example 4) Tracking force 3.5 N 4.3 N 5,0 N 4.5 N 5.2 N

Claims (7)

1. A laminate comprising metal oxide nanoparticles modified on the surface with a stabilizer and having a high proportion of α-alumina, where the stabilizer is a silane or siloxane or mixtures thereof.
2. The laminate as claimed in claim 1, wherein the nanoparticles comprise up to 50% by weight of a further oxide, mixtures or genuine solid solutions being present.
3. A laminate as claimed in claim 1 comprising metal oxide nanoparticles having a mean particle size of from 1 nm to 900 nm and an α-alumina content of 50-100%.
4. A laminate comprising metal oxide nanoparticles having a high proportion of α-alumina, wherein the nanoparticles comprise up to 50% by weight of a further oxide from the series consisting of the rare earths or zirconium or hafnium.
5. The laminate as claimed in any of claims 1 to 4, which additionally comprises alumina having a fineness in the µm range.
6. The laminate as claimed in any of claims 1 to 5, wherein the metal oxide nanoparticles are present in the overlay.
7. A process for the production of laminates as claimed in claim 1, wherein a dispersion of nanoparticles having a high proportion of α-alumina in a solvent, preferably water, is mixed with an impregnating resin for the production of laminates, and the laminate is completed in the usual manner.