Dispersion and method for modifying a surface with water repellent silica
Abstract
Dispersion for the modification of a surface with hydrophobicized silicic acid, comprising 0.1 to 25% by weight of hydrophobicized silicic acid, 8 to 90% by weight of at least one alcohol selected from ethanol, 1-propanol and 2-propanol, 7 at 89% by weight of water, 0 to 30% by weight of solvents not miscible with water and 0.04 to 5% by weight of at least one carboxyvinyl polymer, the carboxyvinyl polymer being presented in neutralized form
Term
3.5 yearsto projected expiry
Projected expiry 16 March 2030, counted from filing; an application has no term until it is granted.
- Priority
- Filed
- Published
- Today
- Projected expiry
14 claims: 1 independent, 13 dependent
- 1ES 2 425 384 T3 REIVINDICACIONES 1. - Dispersión para la modificación de una superficie con ácido silícico hidrofobizado, que comprende 0,1 a 25% en peso de ácido silícico hidrofobizado, 8 a 90% en peso de al menos un alcohol elegido de etanol, 1-propanol y 2-propanol, 7 a 89% en peso de agua, 0 a 30% en peso de disolventes no miscibles con agua y 0,04 a 5% en peso de al menos un polímero de carboxivinilo, presentándose el polímero de carboxivinilo en forma neutralizada.
- 2- Dispersión según la reivindicación 1, caracterizada por que el ácido silícico hidrofobizado presenta un valor mediano, referido al peso, de la distribución por tamaño de las partículas en el intervalo de 50 a 800 nm, preferiblemente de 50 a 200 nm.
- 3- Dispersión según la reivindicación 1 ó 2, caracterizada por que el ácido silícico hidrofobizado se preparó mediante desmenuzamiento de partículas de un ácido silícico hidrofobizado en una suspensión que contiene al menos un alcohol elegido de etanol, 1-propanol y 2-propanol y al menos un silazano de la fórmula (I) o (II) (I) (R 1 R 2 R 3 Si)2NR 4 (II) ciclo-(R 1 R 2 SiNR 4 )m en donde los radicales R 1 , R 2 , R 3 , independientemente uno de otro, son radicales hidrocarbonados con 1 a 12 átomos de carbono, el radical R 4 es hidrógeno o metilo y m es de 3 a 8.
- 4- Dispersión según una de las reivindicaciones 1 a 3, caracterizada por que el polímero de carboxivinilo está neutralizado con una alcanolamina, preferiblemente tetrahidroxipropiletilendiamina.
- 5- Dispersión según una de las reivindicaciones 1 a 4, caracterizada por que el polímero de carboxivinilo es un copolímero que comprende, como unidades monómeras, a) ácido acrílico y/o ácido metacrílico, y b) un éster del ácido acrílico y/o del ácido metacrílico con un alcohol C1-4.
- 6- Dispersión según una de las reivindicaciones 1 a 4, caracterizada por que el polímero de carboxivinilo es un copolímero reticulado que comprende, como unidades monómeras, a) ácido acrílico y/o ácido metacrílico, y b) un éster del ácido acrílico y/o del ácido metacrílico con un alcohol C10-30.
- 7- Dispersión según una de las reivindicaciones 1 a 6, caracterizada por que la dispersión contiene hasta 30% en peso de agua y, adicionalmente como inductor de la adherencia, un polisiloxano de la fórmula (III) o (IV) (III) (CH3)3SiO[(CH3)R 5 SiO]nSi(CH3)3 (IV) ciclo-[(CH3)R 5 SiO]p, en donde los radicales R 5 , distribuidos estadísticamente, son grupos metilo o radicales hidrocarbonados con 6 a 24 átomos de carbono, en donde al menos uno de los radicales R 5 no es metilo, n es de 1 a 100 y p es de 3 a 100.
- 8- Dispersión según la reivindicación 7, caracterizada por que el polisiloxano presenta un peso molecular medio de menos de 10000 g/mol, preferiblemente de menos de 1000 g/mol.
- 9- Uso de una dispersión según una de las reivindicaciones 1 a 8 para la modificación de una superficie con ácido silícico hidrofobizado.
- 10- Procedimiento para la modificación de una superficie con ácido silícico hidrofobizado, caracterizado por que una dispersión conforme a una de las reivindicaciones 1 a 8 se aplica sobre la superficie con un proceso de aplicación exento de gotas. 11
- 11- Procedimiento según la reivindicación 10, caracterizado por que la dispersión se aplica sobre la superficie mediante restriego con un paño o esponja, mediante aplicación con un pincel o un cepillo o mediante rodadura con ES 2 425 384 T3 un rodillo de aplicación.
- 12- Procedimiento según la reivindicación 10, caracterizado por que la superficie se sumerge en la dispersión y se deja que la dispersión en exceso escurra de la superficie.
- 13- Procedimiento para la preparación de una dispersión según una de las reivindicaciones 1 a 8, que comprende a) el desmenuzamiento de partículas de un ácido silícico hidrofobizado a un valor mediano de la distribución por tamaño de las partículas en el intervalo de 50 a 800 nm, preferiblemente de 50 a 200 nm, en una suspensión que contiene al menos un alcohol elegido de etanol, 1-propanol y 2-propanol y al menos un silazano de la fórmula (I) o (II) (I) (R 1 R 2 R 3 Si)2NR 4 (II) ciclo-(R 1 R 2 SiNR 4 )m en donde los radicales R 1 , R 2 , R 3 , independientemente uno de otro, son radicales hidrocarbonados con 1 a 12 átomos de carbono, el radical R 4 es hidrógeno o metilo y m es de 3 a 8, b) preparación de una disolución acuosa concentrada de un polímero de carboxivinilo neutralizado, c) adición de la disolución de la etapa b) a un medio que contiene más de 60% en peso de al menos un alcohol elegido de etanol, 1-propanol y 2-propanol, y d) adición de la suspensión de la etapa a) a la mezcla de la etapa c).
- 14- Procedimiento para la preparación de una dispersión según una de las reivindicaciones 1 a 8, que comprende a) el desmenuzamiento de partículas de un ácido silícico hidrofobizado a un valor mediano de la distribución por tamaño de las partículas en el intervalo de 50 a 800 nm, preferiblemente de 50 a 200 nm, en una suspensión que contiene al menos un alcohol elegido de etanol, 1-propanol y 2-propanol y al menos un silazano de la fórmula (I) o (II) (I) (R 1 R 2 R 3 Si)2NR 4 (II) ciclo-(R 1 R 2 SiNR 4 )m en donde los radicales R 1 , R 2 , R 3 , independientemente uno de otro, son radicales hidrocarbonados con 1 a 12 átomos de carbono, el radical R 4 es hidrógeno o metilo y m es de 3 a 8, y b) adición de la suspensión de la etapa a) a una disolución acuosa de un polímero de carboxivinilo neutralizado.
Independent claims14
169 paragraphs in 10 sections, as filed
ES 2 425 384 T3
DESCRIPTION
Dispersion and procedure to modify a surface with hydrophobicized silicic acid
Object of the invention are dispersions with which surfaces can be modified with hydrophobicized silicic acid, so that they acquire water-repellent properties and, eventually, also self-cleaning, as well as a process for modifying a surface with hydrophobicized silicic acid, in which does not form dusts or aerosols.
It has long been known under the term "Lotus effect" that surfaces, which are hydrophobic and have a surface structure on which only small contact points are formed for water droplets and adhering dirt particles, have repellent properties. water and self-cleaning. The term "self-cleaning" designates in this case surfaces from which dirt particles are detached by drops of water that roll over without the effect of surfactants. Of particular interest are methods by which surfaces can be subsequently modified so that they acquire the desired water-repellent and self-cleaning properties.
From EP 1 475 426 it is known to modify surfaces as desired by spraying on the surface a dispersion of hydrophobic particles in a solution of a silicone wax in a volatile siloxane. Hydrophobic silicic acids can be used as hydrophobic particles. The method known from EP 1 475 426 has the drawback that aerosols containing silicic acid can form during spraying and the surface modified with the hydrophobic particles shows, only after several hours after spraying of the dispersion, sufficient adhesion of the hydrophobic particles to the surface.
Document WO 2007/053266 describes a surface modification by spraying a dispersion of hydrophobicized silicic acid in a volatile solvent, the hydrophobicized silicic acid being prepared by comminuting the particles in the presence of a silazane. The dispersions described in WO 2007/053266 are non-aqueous and contain, in the specific embodiments disclosed, decamethylcyclopentasiloxane as a volatile solvent.
WO 2005/104851 describes aqueous dispersions containing 0.5 to 20% by weight of hydrophobic silicic acid, 0.01 to 10% by weight of a gelling or viscosity-increasing additive and 0.1 to 1% in preservative agent weight. The viscosity-increasing additive can be a neutralized carboxyvinyl polymer. Document WO 2005/104851 further describes spraying the dispersion onto a surface in order to achieve an insecticidal effect on the surface.
The dispersions known from the state of the art must be applied by spraying on the surface to be modified. Tests of applying the dispersions known from the state of the art to a surface by means of a cloth or a brush were unsatisfactory, since in this case only an irregular modification of the surface and the water-repellent and self-cleaning properties of the surface were achieved. modified surface were unsatisfactory.
There is therefore a demand for dispersions with which surfaces can be effectively modified with hydrophobicized silicic acid, without resulting in powders or aerosols containing silicic acid during application to the surface.
It has now been found, surprisingly, that with dispersions containing in suitable proportions an alcohol of the ethanol series, 1-propanol and 2-propanol, water and a neutralized carboxyvinyl polymer it can be achieved, by means of a droplet-free application process, such as by means of a cloth, brush, roller or immersion, a uniform modification of surfaces with hydrophobicized silicic acid, so that the surface acquires water repellent properties and, eventually, also self-cleaning.
Therefore, object of the invention are dispersions to modify a surface with hydrophobicized silicic acid that comprise 0.1 to 25% by weight of hydrophobicized silicic acid, 8 to 90% by weight of at least one alcohol chosen from ethanol, 1- propanol and 2-propanol, 7 to 89% by weight of water, 0 to 30% by weight of water-immiscible solvents and 0.04 to 5% by weight of at least one carboxyvinyl polymer, the carboxyvinyl polymer being present in neutralized form.
ES 2 425 384 T3
Object of the invention is, moreover, a process for modifying a surface with hydrophobicized silicic acid, in which a dispersion according to the invention is applied to the surface with a drop-free application process, as well as processes for the preparation of the dispersion according to the invention.
The dispersion according to the invention comprises 0.1 to 25% by weight of hydrophobicized silicic acid, 8 to 90% by weight of at least one alcohol chosen from ethanol, 1-propanol and 2-propanol, 7 to 89% by weight of water, 0 to 30% by weight of water-immiscible solvents and 0.04 to 5% by weight of at least one carboxyvinyl polymer in neutralized form. The weight data for the carboxyvinyl polymer refers in this case to the amount of carboxyvinyl polymer before neutralization.
Preferably, the dispersion according to the invention comprises 0.5 to 10% by weight of hydrophobized silicic acid, particularly preferably 0.5 to 1.5% by weight. The dispersion according to the invention preferably comprises 10 to 88% by weight of alcohol, particularly preferably 20 to 88% by weight. The dispersion according to the invention preferably comprises 10 to 89% by weight of water, particularly preferably 10 to 79% by weight. The dispersion according to the invention preferably comprises 0 to 10% by weight of water-immiscible solvents. The dispersion according to the invention preferably comprises 0.1 to 5% by weight of carboxyvinyl polymer, particularly preferably 0.1 to 0.2% by weight. The dispersion according to the invention preferably has a viscosity at 20 ° C in the range of 3 to 10,000 mPa * s, particularly preferably a viscosity in the range of 5 to 1000 mPa * s.
The term "dispersion" designates, according to the invention, a mixture in which the hydrophobicized silicic acid is distributed in a liquid phase containing alcohol and water. Preferably, the dispersion according to the invention comprises only one liquid phase. Furthermore, dispersions are preferred which, in addition to the hydrophobicized silicic acid, do not contain any other solids.
The expression "water-immiscible solvents" designates solvents that are not or are only incompletely miscible with water, that is, they have a mixing vacuum with water.
Hydrophobicized silicic acids in the sense of the invention are silicic acids which have covalently bound organic radicals on their surfaces and are not wetted by water. Hydrophobicized silicic acids can be prepared by reacting silicic acids with organosilanes, silazanes, or polysiloxanes. Suitable silicon compounds for the preparation of hydrophobicized silicic acids are known from EP-A 0 722 992, page 3, line 9 to page 6, line 6. Particularly preferred are hydrophobicized silicic acids which were prepared by reacting a silicic acid with a silicon compound of the classes of compounds (a) to (e) and (k) to (m) indicated in EP-A 0 722 992 .
Preferably, the hydrophobicized silicic acid is a hydrophobicized pyrogenic silicic acid that was prepared by hydrophobicizing a pyrogenic silicic acid. Pyrogenic silicic acids are silicic acids that were prepared by flame hydrolysis of a volatile silicon compound. In the case of such flame hydrolysis, dendritic particles are formed in which primary particles of a size less than 50 nm are sintered together. In the case of using hydrophobic pyrogenic silicic acid, the surfaces modified with the dispersion according to the invention have an improved self-cleaning effect.
Hydrophobicized silicic acid preferably has a methanol wettability of at least 40. Methanol wettability is a measure of the hydrophobicity of silicic acid and is determined as the methanol content of a methanol-water mixture as a percentage of volume, in which 50% of the hydrophobicized silicic acid incorporated in the mixture of methanol and water sediments. In the case of a lower methanol content, no wetting takes place, and the hydrophobicized silicic acid remains mostly floating. In the case of a higher methanol content, extensive wetting takes place and most of the hydrophobicized silicic acid settles. In the case of using the hydrophobicized silicic acid with a methanol wetting capacity of at least 40, the surfaces modified with the dispersion according to the invention have an improved self-cleaning effect.
Hydrophobic pyrogenic silicic acid, offered by Evonik Degussa, Aerosil® R805, Aerosil® R974, Aerosil® R202, Aerosil® R812, Aerosil® R812S and Aerosil® R8200, in particular, are suitable for the preparation of the dispersions according to the invention. Aerosil® R812S.
ES 2 425 384 T3
Preferably, the hydrophobicized silicic acid has a median value, based on weight, of the particle size distribution in the range from 50 to 800 nm, particularly preferably from 50 to 200 nm. Hydrophobicized silicic acids are particularly preferred in which less than 5% by weight and, in particular, less than 1% by weight of the particles is greater than 200 nm. By using hydrophobicized silicic acids with particle sizes of this type, the surfaces modified with the dispersion according to the invention show only slight or even no modifications in color and gloss, while in the case of using silicic acid Hydrophobicized with larger particles, the modified surface appears matt and whitish in color.
Particularly preferred are hydrophobicized silicic acids which were prepared by comminution of particles of a hydrophobicized silicic acid in a suspension containing at least one alcohol chosen from ethanol, 1-propanol and 2-propanol and at least one silazane of formula (I) or (II) (I) (R<sup>1</sup>R<sup>2</sup>R<sup>3</sup>Yes) 2NR<sup>4</sup> (II) cyclo- (R<sup>1</sup>R<sup>2</sup>Without R<sup>4</sup>) m where in formulas (I) and (II) the radicals R<sup>1</sup>, R<sup>2</sup>, R<sup>3</sup>, independently of each other, are hydrocarbon radicals with 1 to 12 carbon atoms, the radical R<sup>4</sup> is hydrogen or methyl and m is from 3 to 8. As silazane, hexamethyldisilazane of the formula (I) is preferably used with R<sup>1</sup>, R<sup>2</sup>, R<sup>3</sup> equal to methyl and R<sup>4</sup> equal to hydrogen. Preferably, a hydrophobized pyrogenic silicic acid is deagglomerated, that is, the agglomerates of the primary pyrogenic silicic acid particles are comminuted. The comminution of the particles can take place both by grinding, for example in a ball mill, and also by shear forces, for example in a disperser with a toothed disc or a rotor-stator unit. Preferably, the comminution of the particles takes place in a wet jet mill, in which jets of the suspension are brought into collision with a velocity of preferably more than 300 m / s, particularly preferably 400 to 1000 m / s, and , in particular, from 600 to 900 m / s. This can be achieved by breaking up the suspension of the particles first with a disperser and then conducting the suspension, thus obtained, with a pressure in the range of 50 to 500 MPa through at least two nozzles with holes or slits with a diameter of the same. holes or a width of the slits in the range of 0.05 to 1 mm, preferably 0.1 to 0.5 mm, which are oriented to a common collision point. A suitable wet jet mill for this is known from WO 2005/063369. The comminution of the particles preferably takes place in a suspension that does not contain water, particularly preferably in a suspension that does not contain any other solvent, apart from the alcohols mentioned. By using hydrophobicized silicic acids that were prepared by breaking up this type of particle with the addition of a silazane, the surfaces modified with the dispersion according to the invention show only slight or even no changes in color and gloss. with a high simultaneous self-cleaning effect. By comminuting the hydrophobicized silicic acid in an alcohol of the ethanol, 1-propanol and 2-propanol series, a dispersion with a lower proportion of particles is obtained, compared to comminution in decamethylcyclopentasiloxane, known from WO 2007/053266. large particles with a particle size of more than 200 nm and at the same time, the energy consumption for the crumbling of the particles is reduced. By comminuting a hydrophobic pyrogenic silicic acid in a wet jet mill, in which the jets of a suspension of silicic acid are brought into collision, the proportion of larger particles can be reduced to less than 1% by weight. than 200 nm.
Carboxyvinyl polymers within the meaning of the invention are polymers which can be obtained by polymerization of vinyl monomers and which contain carboxylic acid groups. Carboxyvinyl polymers in neutralized form within the meaning of the invention are carboxyvinyl polymers in which more than 50%, preferably more than 80% of the carboxylic acid groups were neutralized by deprotonation. Preferably, so many carboxylic acid groups are neutralized in the neutralized carboxyvinyl polymer that an aqueous solution of the neutralized carboxyvinyl polymer has a pH value in the range of 6 to 11.
Preferably, the carboxyvinyl polymer is neutralized with an alkanolamine, particularly preferably with a tetrahydroxypropylethylenediamine. Carboxyvinyl polymers neutralized in this way have a high solubility and a good thickening effect in the dispersion according to the invention, also in the case of a low water content, and determine storage stability and workability. improvements of the dispersion according to the invention.
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In a preferred embodiment, the carboxyvinyl polymer is a copolymer comprising as monomeric units, on the one hand, acrylic acid, methacrylic acid or a mixture of both and, on the other hand, at least one ester of acrylic acid, methacrylic acid or a mixture of both with an alcohol with 1 to 4 carbon atoms. Carboxyvinyl polymers of this type act as non-associative thickeners and are available, for example, under the name Aculyn® 33 from Rohm und Haas. Dispersions with these polymers exhibit high storage stability and good workability and at the same time determine good self-cleaning properties on surfaces treated with the dispersion.
In another preferred embodiment, the carboxyvinyl polymer is a cross-linked copolymer which, as monomer units, comprises, on the one hand, acrylic acid, methacrylic acid or a mixture of both and, on the other hand, at least one ester of acrylic acid, methacrylic acid or a mixture of both with an alcohol with 10 to 30 carbon atoms. Carboxyvinyl polymers of this type act as associative thickeners and are available, for example, under the name TEGO® Carbomer 341 ER from Evonik Goldschmidt. With these polymers, high storage stability, good workability and good self-cleaning properties of surfaces treated with the dispersion can be achieved, even with low polymer contents in the dispersion.
The dispersions according to the invention contain both an alcohol, chosen from ethanol, 1-propanol and 2-propanol and mixtures thereof, in an amount of 8 to 90% by weight, as well as water in an amount of 7 to 89% by weight. In the case of a proportion of alcohol in the dispersion of less than 8% by weight, the dispersion is no longer stable on storage, and surfaces modified with such a dispersion have a significantly worse self-cleaning effect and, also in the case of using small particles of silicic acid, appear matt and with a whitish color. If the proportion of water in the dispersion is less than 7% by weight, then surfaces modified with such a dispersion have a substantially worse self-cleaning effect and precipitation of the carboxyvinyl polymer may occur in the dispersion.
The dispersions according to the invention contain hydrophobicized silicic acid in an amount of 0.1 to 25% by weight and at least one neutralized carboxyvinyl polymer in an amount of 0.04 to 5% by weight. In the case of lower contents of hydrophobicized silicic acid or neutralized carboxyvinyl polymer, surfaces modified with such a dispersion no longer have a sufficient self-cleaning effect. In the case of higher contents of hydrophobicized silicic acid or neutralized carboxyvinyl polymer, the viscosity of the dispersion becomes so high that it can only be poorly distributed on one surface.
The dispersions according to the invention can contain up to 30% by weight of water-immiscible solvents. Suitable water-immiscible solvents here are aliphatic, olefinic and aromatic hydrocarbons, ethers, esters, ketones, acetals, alcohols and polydimethylsiloxanes. Suitable aliphatic hydrocarbons are, for example, pentane, hexane, heptane, octane, isooctane and the hydrocarbon mixtures known as petroleum ether. Preferably, low-odor aliphatic hydrocarbon mixtures are used, which are available under the trade names ShellSol® T and ShellSol® D. Preferably, water-immiscible solvents are used which have an evaporation rate according to DIN 53170 of less than 100. The amount of water-immiscible solvents is preferably chosen such that the dispersion comprises only one liquid phase. In the case of water-immiscible solvent contents greater than 30% by weight, low viscous dispersions are obtained with two liquid phases which cannot be applied uniformly on surfaces.
In a preferred embodiment, the dispersion according to the invention still additionally contains as adhesion inducer a polysiloxane of the formula (III) or (IV) (III) (CH3) 3SiO [(CH3) R<sup>5</sup>SiO] nSi (CH3) 3 (IV) cyclo - [(CH3) R<sup>5</sup>SiO] p, where in formulas (III) and (IV) the radicals R<sup>5</sup>, statistically distributed, are methyl groups or hydrocarbon radicals with 6 to 24 carbon atoms, where at least one of the radicals R<sup>5</sup> is not methyl, n is 1 to 100, and p is 3 to 100. In this embodiment, the dispersion contains no more than 30% by weight of water. Preferably, the polysiloxane has a molecular weight of less than 10,000 g / mol, particularly preferably less than 1,000 g / mol. The use of an adhesion inducer of this type achieves a better adhesion of the hydrophobicized silicic acid on the dispersion-modified surface.
ES 2 425 384 T3 surface, so that the water-repellent and self-cleaning property of the surface is preserved for a longer time and the surface can be mechanically stressed with greater intensity without losing its water-repellent and self-cleaning properties.
The dispersion according to the invention can optionally contain still other components such as, for example, flavoring and coloring substances. If the amount of alcohol contained in a dispersion according to the invention is not sufficient by itself to preserve the dispersion and to suppress the growth of bacteria, the dispersion can still additionally contain preservative substances such as, for example, 2 -methyl-4-isothiazolin-3-one, 1,2-benzisothiazolin-3-one or 2-nitropropan-1,3-diol.
In principle, all solid surfaces can be modified with the dispersions according to the invention.
The dispersions according to the invention are suitable for modifying hard surfaces, essentially free of pores, such as glass, vitrified ceramic material, metal, synthetic materials and lacquered surfaces. Surfaces of this type have, after modification with a dispersion according to the invention, water-repellent and self-cleaning properties. In the case of a modification with a dispersion presenting particles with a median particle size distribution in the range of 50 to 200 nm, the modified surfaces show only small or even no modifications in brightness and color, that is that is, the surface modification is not visible. The best combination of self-cleaning properties with little change in the appearance of the modified surface is achieved with dispersions containing a hydrophobicized pyrogenic silicic acid with a median particle size distribution in the range of 50 to 120 nm and less than 2 % by weight of particles with a size greater than 200 nm.
The dispersions according to the invention are also suitable for modifying hard porous surfaces such as stone, concrete, non-vitrified ceramic material or wood. Surfaces of this type have, after modification with a dispersion according to the invention, additionally also a low water absorption, since the water droplets roll off the surface and do not come into direct contact with the surface, so that water is not collected by capillary forces in the pores. In this case, the dispersions according to the invention have the advantage, compared to the dispersions known from the state of the art, that in the case of porous surfaces they do not lead to a modified surface coloration that lasts longer.
The dispersions according to the invention can, however, also be used for the modification of flexible surfaces such as leather, paper or textile materials.
Depending on the amount of hydrophobicized silicic acid applied to the surface, with the dispersions according to the invention, in addition to the water-repellent and self-cleaning effect, also other effects, for example the insecticidal and mite-killing effect known from the WO 2005/104851.
The dispersions according to the invention additionally have the advantage over the dispersions known from WO 2007/053266 that they can also be applied on wet surfaces, without the dispersion having to contain a reactive water-binding solvent. . Therefore, the dispersions according to the invention can be used directly following an aqueous cleaning of a surface for the modification of the surface, without having to wait for a drying of the surface.
The dispersions according to the invention have, with respect to the dispersions known from the state of the art, the advantage that they do not have to be sprayed on the surface in order to give it a self-cleaning effect, but also on the surface. When applied to a surface using a drop-free application process, they modify the surface so that it acquires water-repellent and self-cleaning properties.
The invention therefore also relates to a process for modifying a surface with hydrophobicized silicic acid, in which a dispersion according to the invention is applied to the surface in a droplet-free application process. Preferably, the dispersion is applied to the surface by scrubbing with a cloth or sponge, by application with a brush or brush, or by rolling with an application roller. Alternatively, the dispersion can also be applied to the surface because the surface is immersed in the dispersion and the excess dispersion is allowed to run off the surface.
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The method according to the invention for modifying a surface has the advantage, compared to the method known from the state of the art, that no silicic acid-containing powders or aerosols can appear in the case of surface modification. , so that even when using hydrophobicized silicic acids with small particle sizes, absorption of the particles into the lungs during treatment can be avoided without additional protective measures.
The dispersions according to the invention and the method according to the invention for the modification of a surface can modify surfaces with hydrophobicized silicic acid in such a way that the hydrophobicized silicic acid particles adhere to the surface and do not or only detach to a small extent by wind, rain or running water. The modification of the surface is therefore resistant to atmospheric agents and resistant to water entrainment. The dispersions according to the invention have in this case, compared to the dispersions known from EP 1 475 426 and WO 2007/053266, the advantage that a firm adherence of the particles to the surface and thus a resistance atmospheric agents are already reached after a short time, generally within a few minutes after application of the dispersion on the surface.
The hydrophobicized silicic acid particles can be detached again from the surface, however, mechanically, e.g. ex. by rubbing or with a high pressure water jet, or by aqueous solutions of surfactants. The dispersions according to the invention and the method according to the invention for modifying a surface thereby make it possible to repeatedly clean a surface and provide it again with water-repellent and self-cleaning properties, without thereby produces an accumulation of substances on the surface over time.
The dispersions according to the invention and the method according to the invention for modifying a surface are particularly suitable for treating vehicle paints and vehicle parts in order to avoid renewed soiling after washing and to achieve a cleaning of the surface by the rain that falls on it. They are also suitable for treating building facades, roofs, window exteriors and solar cells. In the case of a solar cell surface treatment, losses in the degree of action due to fouling of the solar cell surface are additionally avoided.
The dispersions according to the invention and the method according to the invention for modifying a surface are furthermore suitable for hygienically obtaining surfaces after cleaning, since this prevents wetting of the modified surface with water and, in this way, a multiplication of bacteria or molds on the surface is prevented or delayed.
The preparation of the dispersions according to the invention preferably takes place with a process in which, in a first stage, particles are comminuted with a hydrophobicized silicic acid in a suspension containing at least one alcohol chosen from ethanol, 1-propanol and 2-propanol and at least one silazane of formulas (I) or (II) defined above, until the median value of the particle size distribution is in the range of 50 to 800 nm, preferably 50 to 200 nm. The comminution of the particles can take place both by grinding, for example in a ball mill, and also by shear forces, for example in a disperser with a toothed disc or a rotor-stator unit. Preferably, the comminution of the particles takes place in a wet jet mill, in which the jets of the suspension are brought into collision with a velocity of preferably more than 300 m / s, particularly preferably 400 to 1000 m / s. s and, in particular, from 600 to 900 m / s. For this, preferably the suspension of the particles is first comminuted with a disperser, and the suspension thus obtained is then passed at a pressure in the range of 50 to 500 MPa through at least two nozzles with holes or slits with a diameter of the holes or a width of the slits in the range of 0.05 to 1 mm, preferably 0.1 to 0.5 mm, which are oriented to a common collision point. The comminution of the particles preferably takes place in a suspension that does not contain water, particularly preferably in a suspension that does not contain any other solvent, apart from the alcohols mentioned. In a particularly preferred manner, a hydrophobicized pyrogenic silicic acid is deagglomerated, that is to say the agglomerates of the primary pyrogenic silicic acid particles are comminuted. The comminution of the hydrophobicized silicic acid particles preferably takes place in the case of a content of the hydrophobicized silicic acid suspension in the range of 5 to 30% by weight. By choosing such a content, particularly small particles can be obtained even in the case of low energy input.
ES 2 425 384 T3
For the preparation of dispersions according to the invention containing more than 40% by weight of water, the suspension obtained in the first stage is then added to an aqueous solution of a neutralized carboxyvinyl polymer. The aqueous solution of the neutralized carboxyvinyl polymer may contain one of the alcohols used in the first stage.
The preparation of the dispersions according to the invention containing less than 40% by weight of water takes place, on the contrary, preferably with the other steps for the preparation of a concentrated aqueous solution of a neutralized carboxyvinyl polymer, addition of the solution obtained in a medium containing more than 60% by weight of at least one alcohol from the ethanol, 1-propanol and 2-propanol series, and adding the suspension from the first stage to the mixture obtained in this case.
The aqueous solution of the neutralized carboxyvinyl polymer is preferably prepared so that an aqueous dispersion of the carboxyvinyl polymer is mixed with neutralizing agent and stirred until the pH value of the dispersion is in the range of 7 to 9 and the polymer carboxyvinyl has gone into solution.
The dispersions prepared by the process according to the invention have a high dispersion stability and, after application to a surface, provide a particularly high water-repellent and self-cleaning effect.
The following Examples illustrate the invention, but do not limit the scope of the invention.
Examples
Crumbling of hydrophobicized silicic acid in the presence of hexamethyldisilazane
Example 1 (not according to the invention)
A dispersion of Aerosil® R 812 S hydrophobic pyrogenic silicic acid in decamethylcyclopentasiloxane was prepared as described in WO 2007/053266 in Example Q in paragraphs [0179] and [0181]. The median value of the particle size distribution, determined by laser scattering with a Horiba LA-910 apparatus, was 190 nm. The proportion of particles with a particle size greater than 200 nm was 45% by weight.
Example 2 (not according to the invention)
Example 1 was repeated as described in WO 2007/053266 in Example Y in paragraphs [0182] and [0183].
Example 3
To a solution of 2 g of hexamethyldisilazane in 798 g of ethanol, 200 g of hydrophobic pyrogenic silicic acid Aerosil® R 812 S were added with stirring and dispersed with a Dissolver Dispermat® dispersing apparatus from VMA-Getzmann GmbH with a toothed disc with a diameter of 70 mm for 15 min at 2200 min<sup>-1</sup>. The suspension obtained was then ground in a wet jet mill with a jet speed of 700 m / s, the wet jet mill having three nozzles arranged in a plane under 120 ° angles and oriented to a common collision point. The median value of the particle size distribution, by laser scattering with a Horiba LA-910 apparatus, was therefore 84 nm. No particles with a diameter greater than 200 nm were found.
Example 4
The suspension obtained in Example 3 was diluted with an additional 332 g of ethanol.
Preparation of a concentrated aqueous solution of a neutralized carboxyvinyl polymer
Example 5
ES 2 425 384 T3
In 365 g of water, 10 g of the carboxyvinyl polymer TEGO® Carbomer 341 ER were incorporated by dispersion and suspended uniformly, with stirring and slowly. After stirring for 30 min, a mixture of 12.5 g of tetrahydroxypropylethylenediamine and 112.5 g of ethanol was added with stirring, after which a clear viscous solution was formed having a pH value of 7.
Dispersions for modifying a surface
Example 6 (not according to the invention)
As described in WO 2007/053266 for Treatment Composition Example 15, in paragraph [0188], 10 parts by weight of the dispersion obtained in Example 1 was mixed with 90 parts by weight of decamethylcyclopentasiloxane. A very fluid dispersion was obtained from which a part of the dispersed silicic acid was deposited during storage.
Example 7 (not according to the invention)
As described in WO 2007/053266 for Treatment Composition Example 13, in paragraph [0188], 10 parts by weight of the dispersion obtained in Example 2 was mixed with 90 parts by weight of decamethylcyclopentasiloxane. A very fluid dispersion was obtained from which a part of the dispersed silicic acid was deposited during storage.
Example 8
To a mixture based on 86.5 g of water and 1.0 g of ethanol, 2.5 g of the solution of Example 5 were added with stirring. The clear viscous solution obtained was mixed, with stirring, with 10, 0 g of the suspension of Example 4. A viscous dispersion was obtained of which nothing was deposited on storage.
Example 9 (not according to the invention)
To a mixture based on 87.5 g of water and 1.0 g of ethanol were added, with stirring, 1.5 g of the solution of Example 5. The clear viscous solution obtained was mixed, with stirring, with 10, 0 g of the suspension of Example 4. A viscous dispersion was obtained from which a part of the hydrophobicized silicic acid was deposited during storage.
Example 10
To a mixture based on 77.6 g of water and 16.5 g of ethanol were added, with stirring, 2.5 g of the solution of Example 5. The clear viscous solution obtained was mixed, with stirring, with 3, 4 g of the suspension of Example 4. A viscous dispersion was obtained of which nothing was deposited on storage.
Example 11
To a mixture based on 75.0 g of water and 16.6 g of ethanol, 5.0 g of the solution of Example 5 were added with stirring. The transparent viscous solution obtained was mixed, with stirring, with 3, 4 g of the suspension of Example 4. A viscous dispersion was obtained of which nothing was deposited on storage.
Example 12
To a mixture based on 45.0 g of water and 42.5 g of ethanol were added, with stirring, 5.0 g of the solution of Example 5. The clear viscous solution obtained was mixed, with stirring, with 7.5 g of the suspension of Example 4. A viscous dispersion was obtained of which nothing was deposited on storage.
Example 13
To a mixture based on 7.5 g of water, 82.15 g of ethanol and 0.35 g of TEGOPREN® 6801 cetylmethicone were added, with stirring, 5.0 g of the solution of Example 5. The clear viscous solution obtained was mixed, with stirring, with 5.0 g of the suspension of Example 4. A viscous dispersion was obtained from which no
ES 2 425 384 T3 deposited nothing in storage.
Example 14 (not according to the invention)
To a mixture based on 2.5 g of water, 87.15 g of ethanol and 0.35 g of TEGOPREN® 6801 cetylmethicone were added, with stirring, 5.0 g of the solution of Example 5. The mixture obtained was added It was combined, with stirring, with 5.0 g of the suspension of Example 4. A very fluid dispersion was obtained from which solid was deposited on storage.
Example 15
To a mixture based on 25.0 g of water, 64.65 g of ethanol and 0.35 g of cetylmethicone TEGOPREN® 6801 were added, with stirring, 5.0 g of the solution of Example 5. The clear viscous solution The mixture obtained was mixed, with stirring, with 5.0 g of the suspension of Example 3. A viscous dispersion was obtained, of which nothing was deposited on storage.
Example 16
To a mixture based on 6.5 g of water, 66.5 g of ethanol, 10.0 g of decamethylcyclopentasiloxane and 0.35 g of TEGOPREN® 6801 cetylmethicone, 10.0 g of the solution of the Example 5. The clear viscous solution obtained was mixed, with stirring, with 6.65 g of the suspension of Example 4. A viscous dispersion of which nothing was deposited on storage was obtained.
Example 17
To a mixture based on 4.25 g of water, 72.0 g of ethanol, 10.0 g of decamethylcyclopentasiloxane and 0.35 g of TEGOPREN® 6801 cetylmethicone, 10.0 g of the solution of the Example 5. The clear viscous solution obtained was mixed, with stirring, with 3.4 g of the suspension of Example 4. A viscous dispersion was obtained of which nothing was deposited on storage.
Example 18
To a mixture of 6.75 g of water, 76.0 g of ethanol, 6.0 g of ShellSol® D60 mineral oil and 0.35 g of TEGOPREN® 6801 cetylmethicone were added, with stirring, 7.5 g of the solution of Example 5. The clear viscous solution obtained was mixed, with stirring, with 3.4 g of the suspension of Example 4. A viscous dispersion of which nothing was deposited on storage was obtained.
Example 19 (not according to the invention)
10.0 g of the solution of the Example 5. The mixture obtained was combined, with stirring, with 10.0 g of the suspension of Example 4. A very fluid dispersion with two liquid phases was obtained.
Table 1 shows the proportions of hydrophobicized silicic acid Aerosil® R 812 S, ethanol, water, water-immiscible solvents, carboxyvinyl polymer TEGO® Carbomer 341 ER and adhesion inducer TEGOPREN® 6801 in the dispersions of the Examples 6 to 19.
ES 2 425 384 T3
Table 1
Proportions in the dispersions in% by weight
<td>Example</td><td>Aerosil® R 812 S</td><td>Ethanol</td><td>Water</td><td>LM **</td><td>TEGO® Carbomer 341 ER</td><td>TEGOPREN® 6801</td>
<td> 6*</td><td> 0,5</td><td></td><td></td><td> 99,4</td><td></td><td></td>
<td> 7*</td><td> 0,5</td><td></td><td></td><td> 99,5</td><td></td><td></td>
<td> 8</td><td> 1,5</td><td> 10,0</td><td> 88,3</td><td></td><td> 0,05</td><td></td>
<td> 9*</td><td> 1,5</td><td> 9,8</td><td> 88,6</td><td></td><td> 0,03</td><td></td>
<td> 10</td><td> 0,51</td><td> 19,9</td><td> 79,4</td><td></td><td> 0,05</td><td></td>
<td> 11</td><td> 0,51</td><td> 20,6</td><td> 78,7</td><td></td><td> 0,1</td><td></td>
<td> 12</td><td> 1,13</td><td> 50,0</td><td> 48,7</td><td></td><td> 0,1</td><td></td>
<td> 13</td><td> 0,75</td><td> 87,5</td><td> 11,2</td><td></td><td> 0,1</td><td> 0,35</td>
<td> 14*</td><td> 0,75</td><td> 92,5</td><td> 6,2</td><td></td><td> 0,1</td><td> 0,35</td>
<td> 15</td><td> 1,0</td><td> 69,8</td><td> 28,7</td><td></td><td> 0,1</td><td> 0,35</td>
<td> 16</td><td> 1,0</td><td> 74,4</td><td> 13,8</td><td> 10,0</td><td> 0,2</td><td> 0,35</td>
<td> 17</td><td> 0,51</td><td> 77,1</td><td> 11,6</td><td> 10,0</td><td> 0,2</td><td> 0,35</td>
<td> 18</td><td> 0,51</td><td> 80,6</td><td> 12,2</td><td> 6,0</td><td> 0,15</td><td> 0,35</td>
<td> 19*</td><td> 1,5</td><td> 20,4</td><td> 37,3</td><td> 40,0</td><td> 0,2</td><td> 0,35</td>
* not according to the invention ** LM = decamethylcyclopentasiloxane, except for Example 18 with LM = ShellSol® D60
Surface modification with silicic acid dispersions
The dispersions were applied to the surface in all tests with a 2 cm wide brush with synthetic material bristles. The application rate was in each case approx. 100 g / m<sup>2</sup>. The treated surfaces were set upright for drying. Drying time was visually determined as the time from which the surface during drying no longer appeared to be wet. The appearance of the treated surface was assessed after the drying time. The contact angle of water droplets on the surface was determined optically with water droplets of a volume of 50 µl on a horizontal surface with a contact angle measuring instrument OCA35 from DataPhysics Instruments GmbH. The water runoff from the surface was determined by applying drops of water with a volume of 50 pl on the horizontal surface, the surface was then tilted under an angle of 45 ° and the runoff of the water droplets was visually assessed according to the criteria of Table 2. The durability of the modification was determined by pouring water in 2-liter portions from a graduated cylinder onto a treated surface and inclined under an angle of 45 ° until the water droplets remained adhered to the surface with a contact angle of less than 90 °.
Table 2
Evaluation of water droplet runoff from a treated surface
<td>Visually observed runoff behavior</td><td>Evaluation</td>
<td>Drain all the drops of water</td><td> 1</td>
<td>Drops of water drip off and only occasionally adhere to the surface</td><td> 2</td>
<td>Drops of water drip off and adhere to some spots on the surface</td><td> 3</td>
<td>Drops of water drip off and adhere to numerous points on the surface</td><td> 4</td>
<td>Most of the water droplets adhere to the surface, only a few drip off</td><td> 5</td>
<td>All water droplets adhere to the surface</td><td> 6</td>
Example 20
A planed, untreated wood surface was modified with different dispersions of silicic acid and the drying time, the appearance, the contact angle of the water droplets and the drainage of the water droplets were determined with the above mentioned methods. . The results are compiled in Table 3.
ES 2 425 384 T3
Table 3
Modification of a wooden surface with silicic acid dispersions
<td>Silicic acid dispersion</td><td>Drying time</td><td>Appearance</td><td>Contact angle</td><td>Drained of water droplets</td>
<td>Example 6 *</td><td>> 3 h</td><td>Color variation</td><td> < 90°</td><td> 4</td>
<td>Example 7 *</td><td>> 3 h</td><td>Color variation</td><td> < 90°</td><td> 4</td>
<td>Example 8</td><td>15 min</td><td>Invariable</td><td> > 140°</td><td> 3</td>
<td>Example 13</td><td>15 min</td><td>Invariable</td><td> > 140°</td><td> 2</td>
<td>Example 15</td><td>15 min</td><td>Invariable</td><td> > 140°</td><td> 2</td>
<td>Example 16</td><td>10 minutes</td><td>Invariable</td><td> > 140°</td><td> 2</td>
* not according to the invention
Example 21
An untreated sandstone surface was modified with different silicic acid dispersions and the drying time, the appearance, the contact angle of the water droplets and the run-off of the water droplets were determined with the above-mentioned methods. The results are compiled in Table 4.
Table 4
Modification of a sandstone surface with silicic acid dispersions
<td>Silicic acid dispersion</td><td>Drying time</td><td>Appearance</td><td>Contact angle</td><td>Drained of water droplets</td>
<td>Example 6 *</td><td>> 3 h</td><td>Color variation</td><td> < 90°</td><td> 4</td>
<td>Example 7 *</td><td>> 3 h</td><td>Color variation</td><td> < 90°</td><td> 4</td>
<td>Example 8</td><td>15 min</td><td>Invariable</td><td> > 140°</td><td> 5</td>
<td>Example 13</td><td>15 min</td><td>Invariable</td><td> > 140°</td><td> 2</td>
<td>Example 15</td><td>15 min</td><td>Invariable</td><td> > 140°</td><td> 2</td>
<td>Example 16</td><td>10 minutes</td><td>Invariable</td><td> > 140°</td><td> 2</td>
* not according to the invention
Example 22
A wooden surface covered with a synthetic material sheet was modified with different silicic acid dispersions and the drying time, the appearance, the contact angle of the water droplets and the durability of the modification were determined with the above mentioned methods. . The results are compiled in Table 5.
Table 5
Modification of a wooden surface covered with a sheet of synthetic material with silicic acid dispersions
<td>Silicic acid dispersion</td><td>Drying time</td><td>Contact angle</td><td>Durability</td>
<td>Example 6 *</td><td>> 3 h</td><td> > 140°</td><td>6 l</td>
<td>Example 7 *</td><td></td><td></td><td>2 l</td>
<td>Example 15</td><td>15 min</td><td> > 140°</td><td>20 l</td>
* not according to the invention
Example 23
A glass surface was modified with different silicic acid dispersions and the drying time, the appearance, the contact angle of the water droplets and the durability of the modification were determined with the
ES 2 425 384 T3 above mentioned methods. The results are compiled in Table 6.
Table 6
Modification of a glass surface with silicic acid dispersions
<td>Silicic acid dispersion</td><td>Drying time</td><td>Appearance</td><td>Contact angle</td><td>Durability</td>
<td>Example 6 *</td><td>> 3 h</td><td>Irregularly whitish</td><td> > 140°</td><td>2 l</td>
<td>Example 16</td><td>30 min</td><td>Barely visible whitish</td><td> > 140°</td><td>> 40 l</td>
* not according to the invention
Examples 20 and 21 demonstrate that with the dispersions according to the invention, in contrast to the dispersions known from WO 2007/053266, a water repellent modification of the surface can also be achieved on porous and suction surfaces by means of the application of the dispersion with a brush, without essentially modifying the appearance of the surface.
Examples 22 and 23 demonstrate that the dispersions according to the invention, in contrast to the dispersions known from WO 2007/053266, dry on non-porous surfaces in a faster and more uniform way and determine a more durable modification.
Example 24 (not according to the invention)
A mixture of 15% by weight of Aerosil® R 812 S hydrophobic pyrogenic silicic acid, 82% by weight of decamethylcyclopentasiloxane and 3% by weight of hexamethyldisilazane was ground in a wet jet mill twice as described in Example 3. The median value of the particle size distribution, determined by laser scattering with a Horiba LA-910 apparatus, was 286 nm after the first grind and 132 nm after the second grind. The proportion of particles with a particle size greater than 200 nm was 93% by weight after the first grinding and 6% by weight after the second grinding. The dispersion obtained was mixed with 2 parts by weight of decamethylcyclopentasiloxane. A very fluid dispersion was obtained from which a part of the dispersed silicic acid was deposited during storage. The Example demonstrates that the dispersions known from WO 2007/053266 in decamethylcyclopentasiloxane are not storage stable even in the dispersion in a wet jet mill.
Contents10
13 members in 8 offices
Priority claims9
| Document | Office | Kind | Date |
|---|---|---|---|
| 09165647 | European Patent Office (EPO) | A | |
| 09165647 | European Patent Office (EPO) | A | |
| 09165647 | European Patent Office (EPO) | – | |
| 2010053355 | European Patent Office (EPO) | W | |
| 2010053355 | European Patent Office (EPO) | W | |
| 09165647 | – | – | – |
| EP20090165647 | – | – | – |
| PCTEP2010053355 | – | – | – |
| WO2010EP53355 | – | – | – |
Members13
| Document | Office | Kind | |
|---|---|---|---|
| CA2768328A1 | Canada | A1 | |
| WO2011006684A1 | World Intellectual Property Organization (WIPO) | A1 | |
| AU2010272772A1 | Australia | A1 | |
| US2012114865A1 | United States of America | A1 | |
| EP2454330A1 | European Patent Office (EPO) | A1 | |
| CN102498179A | China | A | |
| EP2454330B1 | European Patent Office (EPO) | B1 | |
| CA2768328C | Canada | C | |
| ES2425384T3This record | Spain | T3 | |
| AU2010272772B2 | Australia | B2 | |
| US8933164B2 | United States of America | B2 | |
| CN102498179B | China | B | |
| BR112012001081A2 | Brazil | A2 |
Numbers
- Publication
- 2425384
- Publication, DOCDB
- 2425384
- Publication, EPODOC
- ES2425384T
- Application
- 10708777
- Application, DOCDB
- 10708777
- Application, EPODOC
- ES20100708777T
Titles2
- Spanish
- Dispersión y procedimiento para modificar una superficie con ácido silícico hidrofobizado
- English
- Dispersion and procedure to modify a surface with hydrophobicized silicic acid
Classification
- CPC, 13
- C09D1/02
- B82Y30/00
- C01P2004/62
- C01P2004/64
- C01P2006/22
- C08K3/36
- C08K9/06
- C09C1/3081
- C09D5/1618
- C09D7/62
- C09D7/67
- C09D7/68
- Y10S977/773
- IPC, 4
- C09D1 02
- C09C1 30
- C09D5 16
- C09D7 12