EP1846525A1 - Varnish containing particles with protected isocyanate groups - Google Patents

Abstract

The invention relates to coating formulations (B1) containing a) 20-90 % by weight, in regard to a solid material fraction, a reactive group varnish resin (L), b) 1-90 % by weight, in regard to a solid material fraction, a varnish hardener (H) exhibiting reactive functions by which it reacts with the reactive groups of the varnish resin (L) under heat treatment during a varnish hardening, c) 0.1-40 % by weight, in regard to a solid material fraction, particles containing core consisting of atoms selected from metal, silicon and oxygen atoms or made of a silicon resin, wherein the particles (p) comprises, on the surfaces thereof, at least one isocyanate protected group which releases an isocyanate function by heat treatment associated with a protection group removal, more than 50 % of the isocyanate protected groups are provided with the protection groups whose separation temperature is less than the reaction temperature of the varnish resin (L) functional groups with functional groups of the hardener (H), d) 0-90 % by weight, in regard to the entire coating formulation (B1), a solvent or a solvent mixture and e) optionally, other varnish components and additive.

Description

 Paints containing particles with protected isocyanate groups

The invention relates to coating formulations, especially topcoats and clearcoats, which contain particles which have protected isocyanate groups on their surface.

Particles - in particular nanoparticles - containing coating systems are state of the art. Corresponding coatings are described, for example, in EP 1 249 470 or WO 03/16370. The particles lead to an improvement in the properties of the corresponding coatings, in particular with regard to their scratch resistance and their chemical resistance.

A frequently occurring problem when using the - usually inorganic - particles in organic coating systems consists in a usually insufficient compatibility of particles and paint matrix. This can lead to the particles not being able to be dispersed sufficiently well in a coating matrix. In addition, even well dispersed particles can settle at longer stand or storage times, which may be larger aggregates or. Form agglomerates that can not or only with a redispersion can be poorly separated into the original particles. The processing of such inhomogeneous systems is extremely difficult in j edem ^'case, sometimes even impossible. Paints that have smooth surfaces after their application and hardening can usually not be produced in this way or only very cost-intensive.

It is therefore advantageous to use particles which have organic groups on their surface which lead to better compatibility with the coating matrix. In this way, the inorganic particle is "masked" by an organic shell, in which case particularly favorable coating properties can be achieved if the organic functions on the In addition, particle surfaces are also reactive with respect to the paint matrix, so that they intermingle with the paint matrix

Curing conditions of the corresponding paint can react with the matrix. This makes it possible to chemically incorporate the particles into the matrix during coating curing, which often results in particularly good mechanical properties as well as improved chemical resistance. Such systems are described, for example, in DE 102 47 359 A1, EP 832 947 A or EP 0 872 500 A1.

Furthermore, the use of coatings containing a nanoparticle-modified binder is also known. These can be prepared by reacting the reactive functionalized particles with a binder having a complementary function. D. H . Here, the organofunctional particle is chemically incorporated into the paint matrix not only during paint curing but also during binder production. Such systems are described for example in EP 1 187 885 A or WO 01/05897.

In a particularly important type of lacquer, a lacquer resin of hydroxy-functional prepolymers is used, which are reacted during lacquer hardening with an isocyanate-functional hardener. These polyurethane coatings are characterized by particularly good properties, for example by a superior chemical resistance, in contrast, there is still room for improvement, especially in the scratch resistance of these systems. Typically, they are used in particularly high-quality and demanding fields of application, for example as clear or. Topcoats for OEM coatings in the automotive and automotive industries. Likewise, most refinish paints for automotive repairs consist of such isocyanate curing systems.

Typically, a distinction is made between two different polyurethane coating systems, the so-called 2K and 1K systems. The former consist of two components, one of which consists essentially of the isocyanate hardener, while the paint resin with its isocyanate-reactive groups in the second component is included. Both components must be stored and transported separately and may only be mixed shortly before processing, since the finished mixture has only a very limited pot life. Often cheaper, therefore, are the so-called IK systems, which consist of only one component in which there is a hardener with protected isocyanate groups in addition to the paint resin. IK paints are thermally cured, whereby the protecting groups of the isocyanate units are removed, and the deprotected isocyanates can then react with the paint resin. Typical Ξinbrenntemperaturen of such 1K paints are 130-160 ⁰ C.

With these high-quality paints, a further property improvement would be desirable. This applies in particular to vehicle paints. So especially the achievable scratch resistance of conventional car paints is not sufficient, so that it is z. B. In the washing line by particles in the washing water to a noticeable scratching of the paint comes. In the long term, the gloss of the paint is sustainably damaged. Here would be desirable formulations that can achieve better scratch resistance.

A particularly advantageous way to solve this problem is the use of particles having protected on its surface isocyanate functions. Become such. Particles are used in IK polyurethane paints, so during isocyanate curing, the isocyanate functions are released on the particle surfaces and the particle is chemically incorporated into the paint. In addition, the protected isocyanate functions improve the compatibility of the particles and the coating matrix.

Such particles containing protected isocyanate functions are already known in principle. Typically, they are prepared by condensing particles with free silicon or metal hydroxide functions with alkoxy-functional organosilicon compounds whose organic moiety contains protected isocyanate functions. Such masked iso- cyanate-containing organosilicon compounds have already been described, for. B. in DE 34 24 534 A1, EP 0 212 058 B1, JP 08-291186 or JP 10-067787. The particles having protected isocyanate functions themselves and their use in coatings are described, for example, in EP 872 500 A.

In fact, the scratch resistance of paints can be markedly increased by the incorporation of such particles. However, no optimal results are obtained in all of the methods described in the prior art for the use of these particles.

The object of the invention was therefore to provide a coating which contains particles which have protected NCO groups on their surface, wherein this coating should be distinguished by further improved properties, in particular a further improved scratch resistance.

The invention relates to coating formulations (Bl) containing a) 20-90 wt. %, based on the solids content, of a coating resin (L) having reactive groups, b) 1 to 90% by weight. -%, based on the solids content, of a paint curing agent (H), which has reactive functions with which it reacts with the reactive groups ^{' of} the coating resin (L) in the case of paint hardening during thermal treatment, c) 0, 1-40 wt. -%, based on the solids content, of particles (P) containing a core consisting of atoms selected from metal, silicon and oxygen atoms, or of silicone resins, wherein the particles (P) on their surface over at least have a protected isocyanate group which releases an isocyanate function on thermal treatment with the elimination of a protective group, wherein more than 50% of the protected isocyanate groups are provided with protective groups whose cleavage temperature below the reaction temperature of the reaction of the functional groups of the paint resin (L) with those of the hardener (H) is located. d) 0-90% by weight, based on the total coating formulation (B1), of a solvent or of a solvent mixture and e) if appropriate, further coating components and additives.

The solids content comprises diej enigen paint components that remain in the paint during the paint curing.

Typical removal temperatures of the isocyanate-protecting groups of the particles (P) and the reaction temperature of the functional groups of coating resin (L) and hardener (H) can generally be found in the relevant literature known to the person skilled in the art. Furthermore, they can also be determined by standard methods such as dynamic difference calorimetry (DSC) or, if the functional groups are protected isocyanate functions, also by thermogravimetry (TG). These measuring methods are state of the art and known to the person skilled in the art.

Insofar as the difference between the temperature of the cleavage of the Isocyanatschutzgruppen the particles (P) and the reaction temperature of the functional groups of paint resin (L) and hardener (H) can not be derived clearly from literature data, these features are defined in the context of this invention as follows: As cleavage temperature the Isocyanatschutzgruppen applies derjenige temperature at which the cleavage rate of the protecting groups - measured by DSC or TG at a heating rate of 1 ° C / min - reaches a maximum. The reaction temperature of the functional groups of the coating resin (L) with those of the curing agent (H) is defined as the temperature at which the reaction rate between the two reaction partners reaches a maximum using the same measuring method.

If the particles (P) are prepared according to the method described below from particles (P1) and hydrolyzable organosilanes (A) which contain at least one protected isocyanate function, the temperature of the separation becomes protected Isocyanate-functional of the particle (P) not determined by a measurement of the particles (P) itself, but by a measurement of the silane precursor (A). This method is advantageous because the particles (P) often can not or only poorly isolated but are stable only in a dissolved state.

If paint resin (L) and / or hardener (H) each have several functional groups with different reactivity, d. H . When varnish curing involves various reactions between varnish resin (L) and hardener (H)), each having different reaction temperatures, the above definitions refer to the reaction which is quantitative (i.e., in moles) during thermal varnish curing. -% of the reactive functions involved in the current reaction) predominates.

Preference is given to coating formulations (B1) comprising particles (P) whose protected isocyanate groups are provided with protective groups of at least 70%, particularly preferably at least 90%, in particular 100%, whose cleavage temperature below the reaction temperature of the reaction of the functional groups of the coating resin (L ) with those of the hardener (H). In a preferred embodiment of the invention, the coating formulations (B1) contain hydroxyl-functional coating resins.

Furthermore, coating formulations (B1) are preferred whose coating hardener (H) contains a melamine-formaldehyde resin. However, particularly preferred are coating formulations (B2) which comprise a coating hardener (H) which, like the particles (P), has protected isocyanate groups which release an isocyanate function on thermal treatment with elimination of a protective group. In this preferred embodiment of the invention, the reaction temperature between paint resin (L) and curing agent (H) is defined as identical to the temperature of the release of the protective groups of the curing agent (H). This is useful because the released by the deprotection NCO groups normally react immediately with the paint resin. D. H . preferred subject of the invention are coating formulations (Bl) containing a) 20-90 wt. % by weight, based on the solids content, of a hydroxyl-functional coating resin (L), b) 1-90% by weight, based on the solids content, of a paint curing agent (H) which contains protected isocyanate groups which on thermal treatment split off a Protective group release an isocyanate function, c) 0, 1-40 wt. -%, based on the solids content, of particles (P) containing a core consisting of atoms selected from metal, silicon and oxygen atoms, or of silicone resins, wherein the particles (P) on their surface over at least have a protected isocyanate group which releases an isocyanate function upon deprotection upon thermal treatment, with more than 50% of the protected isocyanate groups having protecting groups having a lower cleavage temperature than 60% of the protected isocyanate groups of the curing agent (H), d) 0-90% by weight, based on the total coating formulation (B1), of a solvent or of a solvent mixture and e) if appropriate, further coating components and additives.

In this case, preferably at least 70%, particularly preferably at least 90% of the protected NCO groups of the particles (P) are provided with protective groups which have a lower cleavage temperature, than 60%, preferably 70%, particularly preferably 90% of the protected groups of the protected Isocyanate groups of the hardener (H). In this case, the protective groups of all protected isocyanate groups of the particles (P) in the coating formulations (B1) particularly preferably have a lower cleavage temperature than all protecting groups of the protected isocyanate groups of the hardener (H).

The removal temperatures of the protective groups of curing agent (H) and particles (P) are preferred by those skilled in the art known literature taken. In case of doubt, however, they can be determined by the method described above.

In a preferred method of determination of the cleavage temperature, the temperature which is at least necessary in order to eliminate at least 80% of the protective groups of the corresponding type within 30 minutes with liberation of free isocyanate functions is determined. The removal temperature can be determined for example by thermogravimetric method.

If the particles (P) are prepared by the method described below from particles (P1) and hydrolyzable organosilanes (A) which contain at least one protected isocyanate function, the removal temperature of the protected isocyanate functions of the particles (P) preferably will not be determined by a measurement the particle (P) itself, but determined by a measurement of the silane precursor (A). This method is advantageous because the particles (P) often can not or only poorly isolated and are stable only in a dissolved state.

The invention is based on the discovery that the coatings produced from the coating formulations (B1) according to the invention in which the protective groups of the protected isocyanate functions of the particles (P) have a cleavage temperature below the reaction temperature of the coating resin (L) and hardener (H), have better scratch resistance than corresponding coatings that do not meet this condition. This applies in particular to coating formulations (B1) which, in addition to the particles (P), contain a hydroxy-functional coating resin (L) and the hardener (H) which, like the particles (P), has protected isocyanate groups. Here, the coating formulations (B1) according to the invention, in which the protective groups of the particles have at least a majority of lower cleavage temperature than the (majority of) isocyanate functions of the curing agent, significantly better Scratch resistance as non-inventive coatings in which the protective groups of particles and hardener are identical, on. This effect is due to the fact that the coatings (B1) according to the invention make it possible to improve the chemical incorporation of the particles (P) into the lacquer matrix during lacquer curing.

Another object of the invention are Beschichtungsforrau- lierungen (B2) containing • a) 20-90 wt -.%, Based on the solids content of a coating resin (L) having reactive groups, b) 1-90 wt -.%, Based on the solids content, of a paint hardener (H), which has reactive functions with which it reacts with the reactive groups of the paint resin (L) in the case of paint curing on thermal treatment, c) 0, 1-40 wt. -%, Based on the Solids, particles (P) containing a core consisting of atoms selected from metal, silicon and oxygen atoms, or silicone resins, the particles (P) having on their surface at least one protected isocyanate group, the on thermal treatment with the elimination of a protective group releases an isocyanate function, wherein more than 50% of the protected isocyanate groups of the particles (P) are provided with protective groups which have a lower cleavage temperature d) 0-90% by weight, based on the total coating formulation (B2), of a solvent or of a solvent mixture and e) optionally further coating components and additives.

Coating formulations (B2) comprising particles (P) whose protected isocyanate groups are provided with at least 70%, particularly preferably at least 90%, protective groups which have a lower cleavage temperature than butane oxime are preferred. Most preferably, the protecting groups of all protected isocyanate groups of the particles (P) in the coating formulations (B2) has a lower cleavage temperature than butane oxime.

Preference is given to coating formulations (B2) which contain particles (P) whose protected isocyanate groups are at least 50%, preferably at least 70% or 90%, particularly preferably 100%, with diisopropylamine, 3, 5-dimethylpyrazole or 2-isopropylimidazole are protected.

In a preferred embodiment of the invention, the coating formulations (B2) comprise hydroxy-functional coating resins (L).

Furthermore, coating formulations (B2) are preferred whose paint curing agent (H) contains a melamine-formaldehyde resin. However, particularly preferred are coating formulations (B2) which comprise a coating hardener (H) which, like the particles (P), has protected isocyanate groups which release an isocyanate function on thermal treatment with elimination of a protective group.

D. H . Coating formulations (B2) comprising a) 20-90% by weight are particularly preferred. -%, based on the solids content of a hydroxyl-functional paint resin (L), b) 1-90 wt. %, based on the solids content, of a paint curing agent (H) which contains protected isocyanate groups which release an isocyanate function on thermal treatment with elimination of a protective group, c) 0.1-40 wt. -%, based on the solids content, particles (P) containing a core consisting of atoms selected from metal, silicon and oxygen atoms, or of silicone resins, wherein the particles (P) on their surface over at least have a protected isocyanate group which releases an isocyanate function upon thermal treatment with elimination of a protective group, wherein more than 50% of the protected isocyanate groups of the particles (P) are provided with protective groups which have a lower cleavage temperature than butane oxime, d) 0-90 wt. %, based on the total coating formulation (B2), of a solvent or of a solvent mixture, and e) optionally further coating components and additives.

In a preferred embodiment of the invention, the coating formulations (B1) or (B2) a) 30-80 wt. %, based on the solids content, of a lacquer resin (L), b) 10-60 wt. -%, based on the solids content of a paint curing agent (H), c) 0, 5-30 wt. -%, based on the solids content, of particles (P) containing a core selected from atoms selected from metal, silicon and

Oxygen atoms, or of silicone resins, wherein the particles (P) have on their surface at least one protected isocyanate group which releases an isocyanate function upon thermal treatment with elimination of a protective group, d) 0-80 wt. -%, based on the total coating formulation (Bl) or (B2), one or more solvents and e) optionally further lacquer components and additives.

With particular preference, the coating formulations (B1) or (B2) a) 40-70 wt. %, based on the solids content, of a paint resin (L), b) 15-50 wt. -%, based on the solids content of a paint curing agent (H), c) 1 -25 wt -.%, Based on the solids content of particles

(P), d) 20-70 wt. %, based on the total coating formulation (B1) or (B2), one or more solvents and e) optionally further paint components and additives.

The proportion of the solvent or solvents in the total coating formulations (B1) or (B2) is particularly preferably from 30 to 60% by weight. %, in particular from 35 to 60% by weight.

In. According to a preferred embodiment of the invention, the particles (P) are obtainable by reacting particles (P1) consisting of atoms selected from the group consisting of metal, silicon and oxygen atoms or silicone resins and having free hydroxyl functions with organosilanes (A ) which a) have at least one hydrolyzable silyl function or at least one hydroxysilyl group, and b) contain at least one protected isocyanate function.

In a particularly preferred embodiment of the invention, silanes (A) of the general formula (I)

(R ¹ O) _{3 n} (R ² ) _n Si-A-NH-C (O) -X (I),

used, where

R - * - hydrogen, alkyl, cycloalkyl or aryl radical having in each case 1 to 6 C atoms, where the carbon chain may be interrupted by nonadjacent oxygen, sulfur or NR ³ groups,

R ^ alkyl, cycloalkyl, aryl or arylalkyl radical having in each case 1 to 12 j C-atoms, where the carbon chain may be interrupted by non ^'nonadjacent oxygen, sulfur or NR ^ groups,

R ^{3 is} hydrogen, alkyl, cycloalkyl, aryl, arylalkyl,

Aminoalkyl or Aspartatesterrest, X is a protecting group which is cleaved off at temperatures of 60 to 300 ⁰ C in the form of HX, and thereby a Isocyanate function releases, A is a bifunctional alkyl, cycloalkyl or aryl radical with

1-10 represent carbon atoms and n can assume the values 0, 1 or 2.

The EA group is preferably methyl or ethyl radicals. The group R 1 is preferably

Methyl, ethyl, isopropyl or phenyl radicals. R ³ preferably has at most 10 carbon atoms, more preferably at most 4 carbon atoms. A preferably represents a (CH 2) 3 group and particularly preferably a CH 2 - group.

The preferred elimination temperatures of the protective groups, in particular HX are at 80 to 200 ⁰ C, particularly preferably at 100 to 170 ⁰ C. As protecting groups HX can be secondary or tertiary alcohols, such as isopropanol or t-butanol, CH-acidic compounds such. B. Diethyl malonate, acetylacetone, ethyl acetoacetate, oximes such as. B. Formaldoxime, acetaldoxime, butane oxime, cyclohexanone oxime, acetophenone oxime, benzophenone oxime or diethylene glycol, lactams, such as. B. Caprolactam, valerolactam, butyrolactam, phenols such as phenol, o-methylphenol, IV-alkylamides such. B. N-methylacetamide, imides such as phthalimide, secondary amines such. B. Diisopropylamine, imidazole, 2-isopropylimidazole, pyrazole, 3, 5-dimethylpryazole, 1, 2, 4-triazole and 2, 5 dimethyl-1, 2, 4-triazole can be used. Preference is given to using protecting groups such as butane oxime, 3, 5-dimethylpyrazole, caprolactam, diethyl malonate, malonic acid methyl ester, acetoacetic ester, diisopropylamine, pyrrolidone, 1, 2, 4-triazole, imidazole and 2-isopropylimidazole. Particular preference is given to using protective groups which allow a low stoving temperature, such as, for example, B. Diethyl malonate, dimethyl malonate, butane oxime, diisopropylamine, 3, 5-dimethylpyrazole and 2-isopropylimidazole. In a further embodiment of the invention, the particles (P) are prepared by reacting OH-functional particles (P1) with organosilanes (A) of the general formula (II)

(R ¹ O) _{3 n} (R ² ) _n Si-A-NR 3 -C (O) -NH-Y- (MH-C (O) -X) _z (II)

in which

R ¹ , R ² , R ³ , A, X and n have the meanings given in the general formula (I),

Y is a (z + 1) -functional aliphatic or aromatic

Rest means and 2 is a number from 1-4, preferably 1 or 2, means.

The reaction between the particles (P1) and the organosilanes (A) preferably takes place directly during the mixing of the reactants. It is particularly advantageous to use silanes (A) of the general formula (I) or (II) in which the spacer A is a CH 2 bridge, since these silanes (A) by a particularly high reactivity with respect to the hydroxyl groups of the particles (Pl) distinguished, so that the functionalization of the particle with these silanes can be carried out especially quickly and at low temperatures, in particular even at room temperature ^'. The particles (P1) can be functionalized both as a dispersion in an aqueous or anhydrous protic or aprotic solvent and in the solid state. In the latter case, the mixing, for example, in a fluidized bed reactor or other known mixing equipment, such as. B. Plowshare mixers, done.

If silanes (A) of the general formula (I) or (II) are used which have only monoalkoxysilyl functions (ie silanes of the general formula (I) or (II) where n = 2), then in the preparation the particle (P) on the addition of Water can be omitted because the monoalkoxysilyl groups can react directly with the hydroxyl functions on the surface of the particles (Pl). If, however, silanes (A) with di- or trialkoxysilyl groups are used (ie silanes of the general formulas (I) or (II) where n = 0 or 1), then the addition of .alpha

Water in the production of the particles (P) often advantageous because the alkoxysilanes then not only with the Si-OH functions of the particles (Pl) but - after their hydrolysis - can also react with each other. This results in particles (P), which have a shell of interconnected silanes (A).

In the preparation of the particles (P), any desired mixtures of the silanes (A) with other silanes (S1), silazanes (S2) or siloxanes (S3) can be used for surface modification in addition to the silanes (A). The silanes (S1) have either hydroxysilyl groups or else hydrolyzable silyl functions, the latter being preferred. In addition, these silanes can have further organ functions, but it is also possible to use silanes (SI) without further organ functions.

Particular preference is given to mixtures of silanes (A) with silanes (SI) of the general formula (III)

(R ¹ O) ₄ _ _a _ _b (R ² ) _a SiR 4 _b (III)

used, where

R ^, R.2 and R.3 given in the general formula (I)

Have meanings, and

R ^{4 are} identical or different SiC-bonded hydrocarbon radicals having 1 to 18 carbon atoms, which are optionally substituted by halogen atoms, amino groups, ether groups, ester groups, epoxy groups, mercapto groups, cyano groups, Isocyanate groups, methacrylic groups or (poly) glycol radicals are substituted, the latter being composed of oxyethylene and / or oxypropylene units, means a 0, 1, 2 or 3, and b is 0, 1, 2 or 3.

In this case, a is preferably 0, 1 or 2, while b is preferably 0 or 1.

As silazanes (S2) resp. Siloxanes (S3) are particularly preferably used hexamethyldisilazane or hexamethyldisiloxane.

As particles (P1) it is possible to use all metal oxide and mixed metal oxide particles (for example aluminum oxides such as corundum, mixed aluminum oxides with other metals and / or silicon, titanium oxides, zirconium oxides, iron oxides), silica particles (for example fumed silica precipitated silica, colloidal silicic acid) or silica compounds in which some valencies of the silicon are provided with organic radicals, d. H. Silicone resins are used. These particles (P1) are characterized in that they have on their surface over metal and / or silicon hydroxide functions via which a reaction with the organosilanes (A) - and optionally the silanes (Sl), silazanes (S2) or Siloxanes (S3) - can be done. The particles (P1) preferably have an average diameter of 1 nm to 100 .mu.m, more preferably of 10 nm to 200 nm.

In a preferred embodiment of the invention, the particles (P 1) consist of fumed silica which is prepared in a flame reaction from silicon compounds, e.g. B. silicon tetrachloride or methyldichlorosilane, or hydrogentrichlorosilane or hydrogenmethyldichlorosilane, or other methylchlorosilanes or alkylchlorosilanes, also in mixture with hydrocarbons, or any volatilizable or sprayable mixtures of organosilicon compounds, It is also possible (greater> 1000 ⁰ C) prepared silicas are used in a wet-chemical route or prepared at high temperature. Particular preference is given to pyrogenic silicas. It can be used hydrophilic as well as hydrophobized silicas.

It is also possible to use mixtures of different metal oxides or silicic acids, such. B. Mixtures of metal oxides or silicic acids of different BET surface area, or mixtures of silicas with different degree of hydrophobization or silylation.

Preferably, the process of surface modification consists of three individual steps, (1) the loading of the silica with the silane, (2) the reaction, (3) the purification of the silica from excess silane or by-products or cleavage products.

The surface treatment is preferably carried out in an atmosphere which does not result in the oxidation of the silylated silica, i. H . preferably less than 10 vol. % Oxygen, more preferably less than 2.5 vol. -%, best results are achieved at less than 1 vol. -% oxygen.

Assignment, reaction and purification can be carried out as a batch or continuous process.

For technical reasons preferred is a continuous

Reaction procedure.

The assignment is preferably carried out at temperatures of -30 to 150 ⁰ C, preferably 20-100 ⁰ C, more preferably the occupation step takes place at 30-50 ⁰ C. The residence time is 1 min - 24 h, preferably 15 min to 240 min, for reasons of space-time yield particularly preferably 15 min to 90 min.

The pressure in the occupancy ranges from weak suppression to 0, 2 bar to overpressure of 100 bar, for technical reasons normal pressure, that is pressure-free working against outside / atmospheric pressure is preferred.

The silanes (A) - optionally in mixtures with other silanes (S1), silazanes (S2) or siloxanes (S3) are preferably added in liquid form, and in particular mixed into the powdered silica. The compounds may be in pure form or as solutions in known technically used solvents such. B. Alcohols, in particular alkanols having 1 to 6 carbon atoms, such as. B. Methanol, ethanol, or isopropanol, ethers such. B. Diethyl ether, THF, or dioxane, or hydrocarbons such as. B. Hexanes or toluene are added. The concentration in the solution is 5 to 95 wt. %, preferably 30-95 wt.%, particularly preferably 50-95 wt. -%.

The admixing is preferably done by nozzle techniques, or similar techniques, such as effective atomization techniques, such as atomization, in 1-fluid nozzles under pressure (preferably 5 to 20 bar), spraying in 2-fluid nozzles under pressure (preferably gas and liquid 2-20 bar), Very fine distribution with atomizers or gas-solid exchange units with movable, rotating or static internals, which allow a homogeneous distribution of the silanes with the powdered silica. Preferably, the silanes (A) - optionally added in mixtures with other silanes (SI), silazanes (S2) or siloxanes (S3) as a finely divided aerosol, characterized in that the aerosol is a sinking rate of 0, 1 - 20 cm / s having .

Preferably, the loading of the silica and the

Reaction with the silanes under mechanical or gas borne

Fluidization. Particularly preferred is the mechanical

Fluidization.

A gas-borne fluidization can be done by any inert gases that do not react with the silanes, the silica, and the silylated silica, so not too

Side reactions, degradation reactions, oxidation processes and

Flame and explosion phenomena lead, as preferably

N2, Ar, other noble gases, CO2, etc. The supply of gases to

Fluidization is preferably carried out in the range of empty tube gas velocities of 0.05 to 5 cm / s, more preferably from 0, 5-2, 5 cm / s.

Particularly preferred is the mechanical fluidization, which takes place without additional gas addition beyond the inertization, by paddle stirrer, anchor agitator, and other suitable stirring elements.

The reaction takes place at temperatures which are lower than the cleavage temperature of the corresponding protective group X of the silane A on the silica surface, preferably at temperatures 0-200 ⁰ C, preferably 20-100 ⁰ C, most preferably ^¬ 20-80 ⁰ C and in a special embodiment at 20-40 ^° C.

The reaction time is 5 minutes to 48 hours, preferably 10 minutes to 4 hours.

Optionally, protic solvents may be added, such as liquid or vaporizable alcohols or water; typical alcohols are isopropanol, ethanol and methanol. It is also possible to add mixtures of the abovementioned protic solvents. Preferably, 1 to 50 wt. -% at protic solvent based on the silica added, particularly preferably 5 to 25%. Particularly preferred is water. Alternatively, acidic catalysts of acidic character in the sense of a Lewis acid or a Brönsted acid such as hydrogen chloride or basic catalysts of basic character in the sense of a Lewis base or a Brönsted base such as ammonia or amines such as triethylamine may be added. Preferably, these are added in traces, i. H . less than 1000 ppm. Most preferably, no catalysts are added.

The cleaning is preferably carried out at a cleaning temperature which are lower than the Abspalttemperatur the corresponding protective group X of the silane A on the silica surface, from 20 to 200 ⁰ C, preferably 5O ⁰ C to 15O ⁰ C, particularly preferably from 50 to 100 ⁰ C. The cleaning step is preferably characterized by movement, with slow movement and low mixing being particularly preferred. The stirrers are advantageously adjusted and moved so that preferably a mixing and fluidizing, but not complete turbulence, occurs.

The cleaning step may further be characterized by increased gas input, corresponding to one

Leerrohrgasgeschwindigkeit of preferably 0, 001 to 10 cm / s, preferably 0, 01 to 1 cm / s. This can be done by any inert gases that do not react with the silanes A, the silica, and the silylated silica, so do not lead to side reactions, degradation reactions, oxidation processes and flame and explosion phenomena, such as preferably N2 ^ Ar, other noble gases, CO2, Etc ..

Additionally, during silylation or subsequent to the cleaning method for mechanical densification of silica are used, such as press rolls, grinding units, such as edge mills and ball mills, screw or screw mixer, screw compressor, briquetting, or compression by suction of the air or gas content by suitable vacuum methods. In addition, in a particularly preferred procedure following the particle preparation and purification, deagglomeration of the silica may be employed, such as pin mills or mill sifting devices such as pin mills, hammer mills, countercurrent mills, impact mills or refining mills.

The silylated fumed silica which can be used as particle (P1) is characterized in particular in that it preferably has an average primary particle particle size of less than 100 nm, preferably a mean primary particle particle size of 5 to 50 nm. In a preferred embodiment of the invention, these primary particles are not isolated, but are components of larger aggregates having a diameter of 50 to 1000 nm.

In a further preferred embodiment of the invention, the particles (P) are prepared from particles (P1) which consist of colloidal silicon or metal oxides which are generally present as a dispersion of the corresponding submicron-sized oxide particles in an aqueous or nonaqueous solvent. Among others, the oxides of the metals aluminum, titanium, zirconium, tantalum, tungsten, hafnium or tin can be used. Particular preference is given to using organic solutions of colloidal silica sols.

The preparation of the particles (P) from colloidal silicon or metal oxides can be carried out by various methods. However, it is preferably carried out by adding the silanes (A) - optionally in mixtures with other silanes (S1), silanes (S2) or siloxanes (S3) - to the aqueous or organic sol. This sol may be acidic, e.g. B. by hydrochloric acid or trifluoroacetic acid, or basic, e.g. B. by ammonia, stabilized. The reaction is usually carried out at temperatures of 0 -200 ⁰ C, preferably at 20 -80 ⁰ C and particularly preferably at 20- 60 ⁰ C. The reaction times are typically between 5 minutes and 48 hours, preferably between 1 and 24 hours. Alternatively, it is also possible to add acidic, basic or heavy metal-containing catalysts. These are preferably used in traces <1000 ppm. However, it is particularly preferred to dispense with the addition of separate catalysts.

Since colloidal Siliciurα- or metal oxide sols are often present in aqueous or alcoholic dispersion, it may be advantageous to the or. the solvents during or after the preparation of the particles (P) against another solvent or. to exchange for another solvent mixture. This can be done for example by distillative removal of the original solvent, wherein the new solvent or. Solvent mixture in one or in several steps before, during or after the distillation can be added. Suitable solvents may be, for example, water, aromatic or aliphatic alcohols, wherein aliphatic alcohols, in particular aliphatic alcohols having 1 to 6 carbon atoms (eg., Methanol, ethanol, n-propanol, isopropanol, π-butanol, isobutanol, t-butanol, the various regiois sorting of the pentanol and hexanol), esters (e.g., ethyl acetate, propyl acetate, butyl acetate, butyl di-glycolate, methoxypropyl acetate), ketones (e.g., acetone, methyl ethyl ketone), ethers (e.g., diethyl ether, t-butyl). butyl methyl ether,

THF) aromatic solvents (toluene, the various regioisomers of xylene but also mixtures such as solvent naphtha), lactones (for example butyrolactone etc.) or lactams (for example N-butyl). Methylpyrrolidone). This aprotic solvent or. Solvent mixtures which consist exclusively or at least partially of aprotic solvents, preferably. Aprotic solvents have the advantage that any solvent residues remaining in the paint during the coating curing are not reactive after the removal of the protective groups from the liberated isocyanate functions. In addition to the production of a particle dispersion, it is also conceivable to isolate the particles (P) as a solid.

Also preferred in the preparation of the particles (P) are silicone resins of the general formula (IV)

(RS ₃ SiO ₁ Z ₂₎ f _e (R ⁵ ₂ 2Si0 / ₂₎ (R ⁵ Si0 _{3/2) g} (SiO _4/2) h ^(IV)

used as particles (Pl), wherein

R 1 is an OR - * function, an OH function, an optionally halogen, hydroxyl, amino, epoxy, thiol, (meth) acrylic, or else NCO-substituted hydrocarbon radical having 1-18 carbon atoms, e is a value greater than or equal to 0, f is greater than or equal to 0, g is greater than or equal to 0, h is greater than or equal to 0, and the sum of e + f + g + h is at least one value of at least 1, preferably at least 5 means.

Preferably, at least 70 mol% of all radicals R 1 are methyl,

Ethyl, isopropyl or phenyl radicals.

In a preferred embodiment, in the

Silicone resins of the general formula (V) sum of e + h at least 90 mol% of the sum of e + f + g + h on. The preparation of the inventive particles (P) from silicone resins of the general formula (IV) and silanes (A) can be carried out by the methods described above.

In a further preferred method for the preparation of the particles (P) is not assumed by hydroxyl-containing particles (Pl). Instead, the particles (P) are prepared by cohydrolysis of the silanes (A) with other silanes (S4). As silanes (S4) it is possible to use all hydrolyzable silanes and silanes containing hydroxysilyl groups. Likewise, siloxanes or silazanes can also be used. Silanes of the general formula (III) are preferably used. Typical examples of suitable silanes (S4) are tetraethoxysilane, tetramethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane or trimethylethoxysilane. Of course, different mixtures of different silanes (S4) can be used. Mixtures can be used which, in addition to the silanes (A), contain only silanes (S4) without additional organo-functions, as well as mixtures which, in addition to the silanes (A), also contain silanes (S4) without additional organo-function and silanes (S4) with additional silanes Organofunction included. In the preparation of the particles (P) via cohydrolysis, the various silanes can be added together or successively. One _. Another process for the preparation of the particles (P) consists in an equilibration of organopolysiloxane resins with the silanes (A). Both the cohydrolysis and the equilibration can be carried out in the presence of catalysts. The principal methods of cohydrolysis and equilibration for the preparation of resins have been widely described in the literature.

In addition to the particles (P) in the coating formulations (Bl) and / or. (B2) contained coating resins (L) preferably consists of hydroxyl-containing prepolymers, more preferably from hydroxyl-containing Polyacrylates or polyesters. Such suitable for the paint preparation hydroxyl-containing polyacrylates and polyesters are well known to those skilled in and widely described in the relevant literature.

Likewise, the coating formulations (B1) or (II) in the coating formulations according to the invention are also suitable. (B2) paint hardener (H), which preferably contain melamine-formaldehyde resins or protected isocyanate groups, which release an isocyanate function on thermal treatment with elimination of a protective group, as the prior art sufficiently well known and widely described in the relevant literature. Hardeners (H) which contain protected isocyanate functions are particularly preferred. Most commonly used for this purpose are di- and / or polyisocyanates which have been previously provided with the respective protective groups. Suitable protecting groups are the same compounds which have been described in the general formula (I) and in the paragraphs following the general formula (I) as protecting groups HX, wherein the

However, protective groups of the particles (P) and of the hardener (H) must, according to the provisos of this invention, be matched to one another. As isocyanates, it is possible in principle to use all customary isocyanates, as are frequently described in the literature. Common diisocyanates are, for example, diisocyanatodiphenylmethane (MDI), both in the form of crude or industrial MDI and in the form of pure 4, 4 "or 2, 4" isomers or mixtures thereof, tolylene diisocyanate (TDI) in the form of its various regioisomers, diisocyanatonaphthalene (NDI), isophorone diisocyanate (IPDI), perhydrogenated MDI (H-MDI), tetramethylene diisocyanate, 2-methyl-pentamethylene diisocyanate, 2, 2, 4-trimethyl-hexamethylene diisocyanate, dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 1, 3 -Diisocyanato-4-methylcyclohe_ <or hexamethylene diisocyanate (HDI). Examples of polyisocyanates are polymeric MDI (P-MDI), triphenylmethane triisocyanate as well as all isocyanurate or biuret trimers of the diisocyanates listed above. In addition, you can Other oligomers of the above isocyanates with blocked NCO groups can be used. All di- and / or polyisocyanates can be used individually or in mixtures. Preference is given here to the isocyanurate and biuret trimerates of the comparatively UV-stable aliphatic isocyanates, particularly preferably the trimers of HDI and IPDI ₇ .

The ratio of the blocked isocyanate groups of the curing agent (H) and the particles (P) over the isocyanate-reactive groups of the coating resin (L) is usually from 0.5 to 2, preferably from 0.8 to 1.5, and more preferably from 1.0 to 1, 2 chosen.

Furthermore, the coating formulations (B1) or (B2) also contain the common solvents and the additives and additives customary in paint formulations. Examples of suitable solvents are aromatic and aliphatic hydrocarbons, esters such as butyl acetate, butyl diglycol acetate, ethyl acetate or methoxypropyl acetate, ethers, alcohols such as isopropanol or isobutanol, ketones such as acetone or butyl methyl ketone, and heterocycles such as lactones or lactams. Another important solvent is water. Thus, water-based coatings are of particular interest because of their low VOC content (volatile organic compounds). As additives would be here u. a. Flow control agents, surface-active substances, adhesion promoters, light stabilizers such as UV absorbers and / or radical scavengers, thixotropic agents and other solids. To generate the desired property profiles of both the coating formulations (B1) and (B2) and the cured coatings are such additives usually indispensable. Likewise, the coating formulations (Bl) or (B2) may also contain pigments. In a preferred process, coating formulations according to the invention (B1) or (B2) are prepared by adding the particles (P) during the mixing process as a powder or as a dispersion in a suitable solvent. In addition, however, another method is preferred in which first of all a masterbatch is produced from the particles (P) and one or more coating components, with particle concentrations of> 15%, preferably> 25% and particularly preferably> 35%. In the preparation of the coating formulations (Bl) or (B2) according to the invention, this masterbatch is then mixed with the other coating components. If it is assumed in the preparation of the masterbatch of a particle dispersion, it may be advantageous if the solvent of the particle dispersion in the course of masterbatch production is removed, for. B. via a distillation step, or exchanged for another solvent or solvent mixture.

The obtained coating formulations (Bl) or (B2) can be used for coating any substrates for improving the scratch resistance, abrasion resistance or chemical resistance. Preferred substrates include plastics such as polycarbonate, polybutylene terephthalate, polymethyl methacrylate, polystyrene or polyvinyl chloride, as well as other coatings applied in an upstream step.

Particularly preferably, the coating formulations (Bl) or (B2) can be used as scratch-resistant clearcoats or topcoats, in particular in the vehicle industry. The coating formulations can be applied by any methods such as dipping, spraying, and casting. Application by a wet-in-wet method is also possible. The curing is carried out by heating under the conditions required for blocked isocyanates and can of course, be accelerated by the addition of catalysts.

All symbols of the above formulas have their meanings independently of one another. In all formulas, the silicon atom is tetravalent.

Unless otherwise indicated, all amounts and percentages are by weight, all pressures 0, 10 MPa (abs.) And all temperatures 20 ⁰ C.

Examples:

Synthesis Example 1: Preparation of an alkoxysilane with butanoxime-protected isocyanate groups (silane 1).

There are 74, 0 g of 2-butanoxime, and 0, 12 g Borchi® catalyst (catalyst VP 0244 from Borchers GmbH) and heated to 80 ⁰ C. Be within 1 h 150 g 00 isocyanatomethyltrimethoxysilane added dropwise and the mixture stirred for 1 h at 80 ⁰ C. ¹ H-NMR and IR spectroscopy show that the isocyanatosilane has been completely reacted.

Synthesis Example 2: Preparation of an alkoxysilane with diisopropylamine-protected isocyanate groups (silane 2).

There are 86, 0 g of diisopropylamine and 0, 12 g Borchi® catalyst (catalyst VP 0244 from Borchers GmbH) and heated to 80 ⁰ C. Within 1 h 150, 00 g

Isocyanatomethyl-trimethoxysilane was added dropwise and the mixture for 1 h at 60 ⁰ C stirred. ¹ H-NMR and IR spectroscopy show that the isocyanatosilane has been completely reacted.

Synthesis Example 3: Preparation of an alkoxysilane with diisopropylamine-protected isocyanate groups (silane 3).

There are 74, 5 g of diisopropylamine and 0, 12 g Borchi® catalyst (catalyst VP 0244 Borchers GmbH) submitted and on 80 ⁰ C heated. Within 1 h 150 g 00 3 - isocyanatopropyltrimethoxysilane were added dropwise and the mixture was stirred for 1 h at 60 ⁰ C. ¹ H-NMR and IR spectroscopy show that the isocyanatosilane has been completely reacted.

Synthesis Example 4: Preparation of fumed silica modified with butanoxime-blocked isocyanate groups

At a temperature of 25 ⁰ C under inert gas N2 to 100 g of pyrogenic hydrophilic silica, with a moisture content of less than 1% and an HCl content less than 100 ppm and with a specific surface area of 300 m ^ / g (measured by the BET method according to DIN 66131 and 66132) (available under the name WACKER HDK® T30 from Wacker-Chemie GmbH, Munich, D), 70 g of the described in Synthesis Example 1 butanoxime-protected isocyanatosilane (silane 1) and 10 ml of water in finely divided form over a Single-fluid nozzle (pressure 5 bar). The so loaded silica is then under N2 for 2 h at a

Fluidized of 25 ⁰ C and then reacted for 2 h at 80 ⁰ C in a 100 1 drying oven under N2 to react.

Obtained is a white silica powder (KP-I) with a homogeneous Silyliermittelschicht.

Synthesis Example 5: Preparation of modified with diisopropylamine ^■ blocked isocyanate groups fumed silica

At a temperature of 25 ° C under inert gas N2 to 100 g of pyrogenic hydrophilic silica, with a moisture content of less than 1% and an HCl content less than 100 ppm and with a specific surface area of 300 m ^ / g (measured by the BET method according to DIN 66131 and 66132) (available under the name WACKER HDK T30 from Wacker-Chemie GmbH, Munich, D), 70 g of the diisopropylamine-protected isocyanatosilane (silane 2) described in Synthesis Example 2 and 10 ml of water in very finely divided Form via a single-fluid nozzle (pressure 5 bar) zugedüst. The so loaded silica is then under N2 for 2 h at a

Fluidized at 25 ° C and then reacted for 2 h at 80 ⁰ C in a 100 1 oven under N2 to the reaction.

A white silica powder (KP-2) with a homogeneous silylating agent layer is obtained.

Synthesis Example 6: Preparation of Butanoxime-Blocked Isocyanate-Modified SiC> 2 Nanosol Particles

1.33 g of the butanoxime-substituted isocyanatosilane prepared according to Synthesis Example 1 (silane 1) are dissolved in 1 g of isopropanol. Then, within 30 minutes, 20 g of a SiC> 2 organosol (IPA-ST from Nissan Chemicals, 30% by weight).

SiO 2, ^{12 nm} average particle diameter) and the pH is adjusted to 3.5 by addition of trifluoroacetic acid. The resulting dispersion is stirred for 3 h at 60 ⁰ C and then for 18 h at room temperature. Thereafter, 18.0 g of methoxypropyl acetate are added. The mixture is stirred for a few minutes and then distilled off a large part of the isopropanol at 70 ⁰ C. D. H . It is distilled until the nanoparticles -Sol has been concentrated to 28, 0 g. The result is a dispersion with a solids content of 26, 2%. The SiO ₂ content is 21.4% and the content of protected isocyanate groups in the dispersion is 0.18 mmol / g. The dispersion is slightly cloudy and shows a Tyndall effect.

Synthesis Example 7: Preparation of diisopropylamine-blocked isocyanate-modified SiC> 2 nanosol-

particles

1.40 g of the diisopropylamine-protected isocyanatosilane prepared according to Synthesis Example 2 (silane 2) are dissolved in 1 g of isopropanol. Then, within 30 minutes, 20 g of a SiC> 2 organosol (IPA-ST from Nissan Chemicals, 30

Gew. % SiC> 2.12 nm mean particle diameter) and the pH is adjusted to 3.5 by the addition of trifluoroacetic acid. The resulting dispersion is stirred for 3 h at 60 ⁰ C and then for 18 h at room temperature. Thereafter, 18.1 g of methoxypropyl acetate are added. The mixture is stirred for a few minutes and then distilled off a large part of the isopropanol at 70 ⁰ C. D. H . It is distilled until the nanoparticle sol has been concentrated to 29.4 g. The result is a dispersion with a solids content of 25, 5%. The SiO ₂ content is 20.8% and the content of protected isocyanate groups in the dispersion is 0.17 mmol / g. The dispersion is slightly cloudy and shows a Tyndall effect.

Synthesis Example 8: Preparation of SiO 2 nanosolvents modified with diisopropylamine-blocked isocyanate groups

particles

1.54 g of the diisopropylamine-protected isocyanatosilane prepared according to Synthesis Example 3 (silane 3) are initially charged. Then within 30 minutes, 20 g of a Siθ2 ~

Organosol (IPA-ST from Nissan Chemicals, 30% by weight SiC> 2 /

12 nm average particle diameter) is added dropwise and the pH is adjusted to 3, 0 by addition of trifluoroacetic acid. The resulting dispersion is stirred for 3 h at 60 ⁰ C and then for 24 h at room temperature. The SiO 2 content is 27, 9% and the content of protected

Isocyanate groups in the dispersion is 0.23 mmol / g. The dispersion is slightly cloudy and shows a Tyndall effect.

Example 1: Preparation of an LC coating formulation comprising a hardener with butanone oxime-blocked isocyanate groups and a pyrogenic silica modified by diisopropylamine-blocked isocyanate groups

For the preparation of an inventive

Coating formulation are 8, 56 g of Desmophen ^® A 365 BA / X of the company. Bayer (acrylate-based paint polyol having a hydroxyl group content of 1, 71 mmol OH / g) with 6, 33 g Desmodur ^® BL 3175 SN from. Bayer (butanoxime-blocked polyisocyanate, blocked NCO content approx. 11%). This corresponds to a molar ratio of protected isocyanate functions to hydroxyl groups of 1, 1: 1. Further, 0, 05 g of a 50% dibutyltin dilaurate solution (in methyl ethyl ketone) and 0, 01 g ADDID ^® 100 of Fa. TEGO AG (flow control agent based on polydimethylsiloxane) and 3.15 g of methyl ethyl ketone, whereby a coating formulation with ca. 50% solids content is obtained.

Into the mixture thus obtained are incorporated, by means of a dissolver 1, 8 g of the diisopropylamine-blocked isocyanate group-modified fumed silica (KP-2) obtained from Synthesis Example 5 to obtain a clear coating formulation.

Comparative Example 1 (not according to the invention): Preparation of an LC coating formulation comprising a hardener with butanone oxime-blocked isocyanate groups and a fumed silica modified by butanone oxime-blocked isocyanate groups

To prepare a comparative coating 8, 56 g of Desmophen ^® A 365 BA / X are Fa. Bayer (acrylate-based Laσk- polyol with a hydroxyl group content of 1.71 mmol / g) with 6.33 g of Desmodur ^® BL 3175 SN Fa. Bayer (butanoxime-blocked polyisocyanate, blocked NCO content about 11%). This corresponds to a molar ratio of protected isocyanate functions to hydroxyl groups of 1, 1: 1. Further, 0, 05 g of a 50% dibutyltin dilaurate solution (in methyl ethyl ketone) and 0, 01 g ADDID ^® 100 of Fa. TEGO AG (flow control agent based on polydimethylsiloxane) and 3.15 g of methyl ethyl ketone, whereby a coating formulation with ca. 50% solids content is obtained. 8 g of the fumed silica (KP-I) modified from butanoxime-blocked isocyanate groups obtained from Synthesis Example 4 are incorporated into the mixture thus obtained by means of a dissolver, giving a clear coating formulation. Preparation and evaluation of paint films from Examples 1 and Comparative Example 1

The coating formulations of Example 1 and Comparative Example 1 are in each case by means of a film applicator Coatmaster ^® 509 MC Fa. Erichsen with a squeegee of gap height 100 microns aufgerakelt on a glass plate. Subsequently, the resulting coating films are dried in a circulating air dryer at 160 ⁰ C for 30 minutes. Both the coating formulations of the examples and of the comparative example give optically flawless, smooth coatings. The gloss of the coatings is with a gloss meter Micro gloss 20 ° the Fa. Byk determined and is in the paint formulation of Example 1 at about 144 gloss units and in the paint formulation of Comparative Example 1 at ca. 131 gloss units.

The scratch resistance of the cured coating films produced in this way is determined using a scouring tester according to Peter-Dahn. For this purpose, a scouring fleece Scotch Brite ^® 2297 with a surface of 45 x 45 mm weighing 500 g is weighted and scratched with 50 strokes. Both before and after completion of the scratching tests, the gloss of the respective coating is measured with a gloss meter Micro gloss 20 ° from the company. Byk measured. As a measure of the scratch resistance of the respective coating, the loss in gloss was determined in comparison with the starting value:

Table 1: Loss loss in the scratch test according to Peter-Dahn * not according to the invention

Example 2: Preparation of a 1K coating formulation containing a curing agent with butanoxime-blocked Isocyanate groups and SiC> 2 nanosol particles modified with diisopropylamine-blocked isocyanate groups

To prepare a coating formulation according to the invention are 4.50 g of an acrylate-based paint polyol having a solids content of 52.4% by weight (solvent: solvent naphtha, methoxypropyl acetate (10: 1)), a hydroxyl group content of 1.46 mmol / g resin solution and a acid number of 10 to 15 mg KOH / g of 2, 69 g Desmodur ^® BL 3175 SN from. Bayer (butanoxime-blocked polyisocyanate, blocked NCO content of 2.64 mmol / g) mixed. Subsequently, 0.76 g of the dispersion prepared according to Synthesis Example 7 is added, which contains SiC 2 nanosol particles which have been modified with diisopropylamine-blocked isocyanate groups. This corresponds to a molar ratio of protected isocyanate functions to hydroxyl groups of 1, 1: 1. Further, 0, 01 g of a dibutyltin dilaurate and 0, 03 g of a 10% solution ADDID ^® 100 of Fa. TEGO AG (flow control agent based on polydimethylsiloxane) in isopropanol, whereby a coating formulation with ca. 50% solids content is obtained. This initially slightly turbid mixture is stirred for 48 h at room temperature to give a clear coating formulation.

Example 3: Preparation of a 1K coating formulation containing a curing agent with butanone oxime-blocked isocyanate groups and SiC 2 nanosol particles modified with diisopropylamine-blocked isocyanate groups

To prepare a coating formulation according to the invention are 4.50 g of an acrylate-based paint polyol having a solids content of 52.4% by weight (solvent: solvent naphtha, methoxypropyl acetate (10: 1)), a hydroxyl group content of 1.46 mmol / g and an acid number from 10 to 15 mg KOH / g of 2, 60 g Desmodur ^® BL 3175 SN from. Bayer (butanoxime-blocked polyisocyanate, blocked NCO content of 2.64 mmol / g) mixed. Subsequently, 2.11 g of the dispersion prepared according to Synthesis Example 7 which contains SiO 2 nanosol particles which have been modified with diisopropylamine-blocked isocyanate groups. This corresponds to a molar ratio of protected isocyanate functions to hydroxyl groups of 1, 1: 1. Further, 0, 01 g of a dibutyltin dilaurate and 0, 03 g of a 10% solution ADDID ^® 100 of Fa. TEGO AG (flow control agent based on polydimethylsiloxane) in isopropanol, whereby a coating formulation with ca. 50% solids content is obtained. This initially slightly turbid mixture is stirred for 48 h at room temperature to give a clear coating formulation.

Example 4: Preparation of a 1-component coating formulation containing a curing agent with butane oxime-blocked isocyanate groups and SiO 2 nanosol particles _# modified with diisopropylamine-blocked isocyanate groups

To prepare a coating formulation according to the invention are 4.50 g of an acrylate-based paint polyol having a solids content of 52.4% by weight (solvent: solvent naphtha, methoxypropyl acetate (10: 1)), a hydroxyl group content of 1.46 mmol / g and an acid number from 10 to 15 mg KOH / g of 2, 69 g Desmodur ^® BL 3175 SN from. Bayer (butanoxime-blocked polyisocyanate, blocked NCO content of 2.64 mmol / g). Subsequently, 0. 57 g of the dispersion prepared according to Synthesis Example 8 are added, which contains SiO 2 nanosol particles which have been modified with diisopropylamine-blocked isocyanate groups. This corresponds to a molar ratio of protected isocyanate functions to hydroxyl groups of 1.1: 1. Furthermore, 0.05 g of a 50% strength are obtained

Dibutyltin dilaurate (in methyl ethyl ketone) and 0, 01 g of ADDID ^® 100 from Fa. TEGO AG (flow control agent based on polydimethylsiloxane) mixed, whereby a coating formulation with ca. 50% solids content is obtained. This initially slightly cloudy mixture is stirred for 24 h at room temperature, leaving a clear Coating formulation is obtained.

Comparative Example 2 (not according to the invention): Preparation of a 1K coating formulation containing a curing agent with butanoxime-blocked isocyanate groups and SiO 2 nanosol

Particles which have been modified with butanoxime-blocked isocyanate groups

To prepare a coating, 4.50 g of an acrylate-based paint polyol having a solids content of 52.4 wt. -% (solvent: solvent naphtha, methoxypropyl acetate (10: 1)), a hydroxyl group content of 1, 46 mmol / g and an acid number of 10 - 15 mg KOH / g of 2, 69 g Desmodur ^® BL 3175 SN from. Bayer (butanoxime-blocked polyisocyanate, blocked NCO content of 2.64 mmol / g) mixed. Subsequently, 0.75 g of the dispersion prepared according to Synthesis Example 6 is added, which contains SiC> 2 nanosol particles which have been modified with butanoxime-blocked isocyanate groups. This corresponds to a molar ratio of protected isocyanate functions to hydroxyl groups of 1.1: 1. Furthermore, 0.05 g of a 50% strength are obtained

Dibutyltin dilaurate (in methyl ethyl ketone) and 0, 01 g of ADDID ^® 100 from Fa. TEGO AG (leveling aid based on polydimethylsiloxane) mixed, whereby a coating formulation with ca. 50% solids content is obtained. This initially slightly cloudy mixture is stirred for 24 h at room temperature to give a clear coating formulation.

Preparation and evaluation of paint films from Examples 2 -4 and Comparative Examples 2 and 3.

The coating formulations of Example 2 -4 and Comparative Examples 2 and 3, j in each case by means of a film-drawing device Coatmaster ^® 509 MC Fa. Erichsen with a squeegee of gap height 120 microns aufgerakelt on a glass plate. Subsequently, the resulting coating films are in a convection oven for 30 minutes at 70 ⁰ C and then dried for 30 min at 15O ⁰ C. Optically perfect, smooth coatings are obtained both from the coating formulations of the examples and from the comparative examples. The gloss of the coatings is with a gloss meter Micro gloss 20 ° the Fa. Byk determined and is in all paint formulation of Example 2 -4 and Comparative Examples 1 and 2 between 160 and 164 gloss units.

The scratch resistance of the cured coating films produced in this way is determined using a scouring tester according to Peter-Dahn. For this purpose a scouring fleece Scotch Brite ^® 2297 with a surface of 45 x 45 mm with a weight of 500 g is weighted. With this, the paint samples are scratched with a total of 40 strokes. Both before and after completion of the scratching tests, the gloss of the respective coating is measured with a gloss meter Micro gloss 20 ° from the company. Byk measured. As a measure of the scratch resistance of the respective coating, the loss in gloss was determined in comparison with the starting value:

Table 2: Loss loss in the scratch test according to Peter-Dahn * not according to the invention

Claims

claims

1. Coating formulations (Bl) containing a) 20-90 wt. %, based on the solids content, of a coating resin (L) having reactive groups, b) 1 to 90% by weight. -%, based on the solids content, of a paint curing agent (H), which has reactive functions, with which it reacts with the reactive groups of the coating resin (L) in the case of paint curing on thermal treatment, c) 0, 1- 40 wt. -%, based on the solids content, of particles (P) containing a core consisting of atoms selected from metal, silicon and oxygen atoms, or of silicone resins, wherein the particles (P) on their surface over at least have a protected isocyanate group which releases an isocyanate function on thermal treatment with elimination of a protective group, wherein more than 50% of the protected isocyanate groups are provided with protective groups whose cleavage temperature below the reaction temperature of the reaction of the functional groups of the coating resin (L) with those of the curing agent ( H) is located. d) 0-90 wt. %, based on the total coating formulation (B1), of a solvent or of a solvent mixture, and e) optionally further coating components and additives.

2. coating formulations (Bl) according to claim 1, comprising a) 20-90 wt. %, based on the solids content, of a hydroxyl-functional lacquer resin (L), b) 1 -90 wt. %, based on the solids content, of a paint curing agent (H) which contains protected isocyanate groups which release an isocyanate function on thermal treatment with elimination of a protective group, c) 0.1-40 wt. -%, based on the solids content, of particles (P) containing a core consisting of atoms selected from metal, silicon and oxygen atoms, or of silicone resins, wherein the particles (P) have on their surface at least one protected isocyanate group which releases an isocyanate function on thermal treatment with the elimination of a protective group, wherein more than 50% of the protected isocyanate groups are provided with protective groups which have a lower cleavage temperature, than at least 55 % of the protective groups of the protected isocyanate groups of the curing agent (H), d) 0-90% by weight, based on the total coating formulation (B1), of a solvent or of a solvent mixture and e) optionally further coating components and additives.

3. Coating formulations (B2) comprising a) 20-90% by weight, based on the solids content, of a coating resin (L) having reactive groups, b) 1-90% by weight. -%, based on the solids content, of a paint curing agent (H), which has reactive functions, with which it reacts with the reactive groups of the coating resin (L) during thermal curing in the paint curing, c) 0, 1 -40 wt -. %, based on the solids content, of particles (P) containing a core selected from atoms selected from metal, silicon and

Oxygen atoms, or consists of _, silicone resins, wherein the particles (P) have on its surface over at least one protected isocyanate group which releases an isocyanate function on thermal treatment with elimination of a protective group, wherein more than 50% of the protected isocyanate groups of

Particles (P) are provided with protective groups which have a lower cleavage temperature than butane oxime, d) 0-90 wt. -%, based on the total coating formulation (B2), of a solvent or of a solvent mixture and e) optionally further coating components and additives.

4. coating formulations (B2) according to claim 3, comprising a) 20-90% by weight, based on the solids content, of a hydroxyl-functional paint resin (L), b) 1-90% by weight, based on the solids content, of a paint curing agent (H) which contains protected isocyanate groups, which release an isocyanate function on thermal treatment with elimination of a protective group, c) 0, 1 -40 Gew. -%, Based on the solids content, particles (P) containing a core selected from atoms, which are selected from metal, silicon and

Oxygen atoms, or of silicone resins, wherein the particles (P) have on their surface over at least one protected isocyanate group which releases an isocyanate function on thermal treatment with elimination of a protective group, wherein more than 50% of the protected isocyanate groups of

Particles (P) are provided with protective groups which have a lower cleavage temperature than butane oxime, d) 0- 90 wt. -%, based on the total coating formulation (B2), of a solvent or of a solvent mixture and e) optionally further coating components and additives.

5. coating formulations (Bl) or (B2) according to claim 1 to 4, comprising a) 30-80 wt. -%, based on the solids content of a paint resin (L), b) 10-60 wt -.%, Based on the solids content of a paint curing agent (H), c) 0, 5-30 wt. -%, based on the solids content, particles

(P), d) 0-80 wt. -% _/ based on the total coating formulation (Bl) or (B2), one or more solvents and e) optionally further coating components and additives.

6. coating formulations (Bl) or (B2) according to claim 1 to 5, wherein the particles (P) are obtainable by a reaction of particles (Pl) consisting of atoms, the are selected from metal, silicon and oxygen atoms, or consist of silicone resins and have free hydroxyl functions, with organosilanes (A) having a) at least one hydrolyzable silyl function or at least one hydroxysilyl group, and b) at least one protected isocyanate function contain .

7. Besσhichtungsformulierungen (Bl) or (B2) according to claim 1 to 6, wherein organosilanes (A) of the general formula

(D

(R ¹ O) _{3 -H} (R ² J _n Si-A-NH-C (O) -X (I),

be used, wherein R ^{1 is} hydrogen, alkyl, cycloalkyl or aryl radical with in each case

1 to 6 C atoms, wherein the carbon chain may be interrupted by non-adjacent oxygen, sulfur or NR ³ groups, R ^{2 is} alkyl, cycloalkyl, aryl or arylalkyl radical having in each case 1 to 12 C atoms, wherein the carbon chain can be interrupted by non-adjacent oxygen, sulfur or NR ³ groups, R ^{3 is} hydrogen, alkyl, cycloalkyl, aryl, arylalkyl,

Aminoalkyl or Aspartatesterrest, X is a protecting group which is cleaved at temperatures of 60 to 300 ⁰ C in the form of HX, thereby releasing an isocyanate function, A is a difunctional alkyl, cycloalkyl or aryl radical

1-10 represent carbon atoms and n can assume the values 0, 1 or 2.

8. coating formulations (Bl) or (B2) according to claim 1 to 6, wherein organosilanes (A) of the general formula

(ID (R ¹ O) _{3 n} (R ² ) _n Si -A-NR ³ -C (O) -NH-Y- (NH-C (O) -X) _z (II)

be used, where

R - * -, A, X and n have the meanings given in the general formula (I) according to claim 6, Y is a (z + 1) -functional aliphatic or aromatic

Rest means and z is a number from 1-4, preferably 1 or 2, means.

9. Coating formulations (B1) or (B2) according to claim 6 to 8, wherein the particles (P1) are selected from aluminum oxides, aluminum mixed oxides with other metals and / or silicon, titanium oxides, zirconium oxides, iron oxides, silicon oxide and silicon oxide compounds which some valences of silicon are provided with organic radicals.

10. Coating formulations (B1) or (B2) according to claim 6 to 8, in which as particles (P1) silicone resins of the general formula (IV)

(R ^S Z _{1 3} SiO _{2) e} f (R ⁵ 2Siθ2 / ₂₎ (R ⁵ Si0 _{3/2) g} (SiO _{4/2) h} (IV)

R ^{5 is} an OR ^ function, an OH function, an optionally halogen, hydroxyl, amino, epoxy, thiol, (meth) acrylic, or NCO-substituted hydrocarbon radical having 1-18 Carbon atoms, e is greater than or equal to 0, f is greater than or equal to 0, g is greater than or equal to 0, h is greater than or equal to 0, and the sum of e + £ + g + h is at least means a value of at least.

11. coating formulations (Bl) or (B2) according to claim 1 to 10, wherein the ratio of the blocked isocyanate groups of the curing agent (H) and the particles (P) over the isocyanate-reactive groups of the paint resin (L) is 0, 5 to 2.

12. Use of the coating formulations (Bl) or (B2) according to claim 1 to 11 as scratch-resistant clear or topcoats.