摘要:
Process for preparing a dispersion of surface-modified silicon dioxide particles having an average particle diameter of not more than 100 nm by high-pressure milling of a preliminary dispersion comprising a) 10% to 50% by weight of surface-modified silicon dioxide particles, b) at least one glycol monoether of the general formula (A): H3C(CH2)m—O—(CH2)n—[O—(CH2)o]p—OH, c) at least one carboxylic ester of the general formula (B): H2x+1Cx—O—CH2—(CHR)—[O—CHR]y—O—C(═O)—CzH2z+1, d) the molar ratio A/B being 10:90 to 40:60 and m, n, o, p, x, y and z being independent of one another. Dispersion obtainable by this process. Process for producing granules of surface-modified silicon dioxide particles by separating off the liquid phase of the dispersion. Granules obtainable by this process. Use of dispersion and granules in coating materials.
摘要:
Process for preparing surface-modified silicon dioxide particles with a mean particle diameter of at most 100 nm, comprising the steps of: a) providing a predispersion b) high-pressure grinding of the predispersion to form a dispersion c) removing the liquid phase of the dispersion, the predispersion comprising a1) surface-modified silicon dioxide particles which are at least partly aggregated, are bonded to the surface-modifying component via Si—O—Si bonds and still have reactive groups on their surface, a2) one or more organosilicon compounds which have at least one silicon-carbon bond and at least one functional group which can react with the reactive groups to form a covalent Si—O—Si bond, and a3) one or more solvents. Redispersible, surface-modified silicon dioxide particles obtainable by this process. Use of these in toner powders, silicone rubber, adhesives and scratch-resistance surface coatings.
摘要:
Aqueous dispersion which comprises hydrophobized silicon dioxide particles and in each case one or more dispersing additives, a basic composition, and which is free of color pigments, inactive fillers and binders, in which the hydrophobized silicon dioxide particles have a methanol wettability of 30 to 60 and are present in the dispersion with a proportion of 0.1 to 50% by weight,—the proportion of water is 30 to 90% by weight based on the dispersion,—the dispersing additive is at least one phosphate ester of an ethoxylated alcohol having 8 to 18 carbon atoms, the proportion of which is 3 to 25% by weight based on the proportion of the hydrophobized silicon dioxide particles,—the basic composition comprises or consists of one or more amines of the general formula RNH2, R2NH and R3N, where R is an alkyl group or a hydroxyl-substituted alkyl group having in each case 2 to 10 carbon atoms, and is present with a proportion of 5 to 30% by weight based on the proportion of hydrophobized silicon dioxide particles,—the dispersion further comprises one or more polyols having 2 to 15 carbon atoms, the proportion of which is 1 to 10% by weight based on the proportion of hydrophobized silicon dioxide particles,—the pH of the dispersion being 9 to 11.
摘要:
Aqueous dispersion which comprises hydrophobized silicon dioxide particles and in each case one or more dispersing additives, a basic composition, and which is free of colour pigments, inactive fillers and binders, in which the hydrophobized silicon dioxide particles have a methanol wettability of 30 to 60 and are present in the dispersion with a proportion of 0.1 to 50% by weight,—the proportion of water is 30 to 90% by weight based on the dispersion,—the dispersing additive is at least one phosphate ester of an ethoxylated alcohol having 8 to 18 carbon atoms, the proportion of which is 3 to 25% by weight based on the proportion of the hydrophobized silicon dioxide particles,—the basic composition comprises or consists of one or more amines of the general formula RNH2, R2NH and R3N, where R is an alkyl group or a hydroxyl-substituted alkyl group having in each case 2 to 10 carbon atoms, and is present with a proportion of 5 to 30% by weight based on the proportion of hydrophobized silicon dioxide particles,—the dispersion further comprises one or more polyols having 2 to 15 carbon atoms, the proportion of which is 1 to 10% by weight based on the proportion of hydrophobized silicon dioxide particles,—the pH of the dispersion being 9 to 11.
摘要:
Provided is a process for preparing surface-modified silicon dioxide particles with a mean particle diameter of at most 100 nm, involving (A) high-pressure grinding of a predispersion having (i) surface-modified silicon dioxide particles which are at least partly aggregated, are bonded to the surface-modifying component via Si—O—Si bonds, and still have reactive groups on their surface; (ii) an organosilicon compound which has a silicon-carbon bond and a functional group which can react with the reactive groups to form a covalent Si—O—Si bond; and (iii) a solvent, to form a dispersion; and (B) removing the liquid phase of the dispersion. Also provided are redispersible, surface-modified silicon dioxide particles obtained by this process, and their use in toner powders, silicone rubber, adhesives, and scratch-resistance surface coatings.
摘要:
Aqueous dispersion obtainable by placing in water an aggregated titanium dioxide powder having a specific surface area of from 20 to 150 m2/g in such an amount that the desired dispersion comprises at least 20 wt. % titanium dioxide, and at least onc amino alcohol having from 1 to 6 carbon atoms, and at least one carboxylic acid from the group comprising dibasic carboxylic acids and/or hydroxycarboxylic acids having from 2 to 6 carbon atoms,—the amino alcohol being present in the dispersion in an amount of from 2.5 to 7.0 μmol./m2 specific surface area TiO2 and the carboxylic acid being present in an amount of from 1.0 to 3.5 μmol./m specific surface area TiO2,—producing a pre-dispersion by introducing energy in an amount of less than 200 kJ/m3 and then producing a dispersion in which the aggregated titanium dioxide powder has a mean, volume-related aggregate diameter of less than 150 nm by grinding the pre-dispersion by means of a high-energy mill at a pressure of at least 500 bar. The dispersion can be used in the coating of glass, ceramics and metal surfaces.
摘要翻译:通过将具有20至150m 2 / g比表面积的聚集二氧化钛粉末放入水中而得到的水分散体,其量使得所需分散体包含至少20wt。 %二氧化钛和至少具有1至6个碳原子的氨基醇,以及至少一种含有2至6个碳原子的二元羧酸和/或羟基羧酸的羧酸, - 存在的氨基醇 在分散体中的量为2.5-7.0μmol/ m 2 SO 3比表面积TiO 2和羧酸的存在量为1.0-3.5μmolol ./m比表面积TiO 2, - 通过引入少于200kJ / m 3的量的能量产生预分散,然后产生分散体,其中 通过在至少500巴的压力下通过高能研磨机研磨预分散体,聚集的二氧化钛粉末具有小于150nm的平均体积相关聚集体直径。 分散体可用于玻璃,陶瓷和金属表面的涂层。
摘要:
A dispersion containing aluminum oxide of pyrogenic origin and water, where the aluminum oxide is present in the form of aggregated primary particles with a BET surface area of 20 to 200 m2/g and has a mean, volume-based aggregate diameter in the dispersion of less than 100 nm, and is surface-modified with (i) organophosphonic acids, or salts thereof, and (ii) at least one hydroxycarboxylic acids or salts thereof.
摘要:
Stable, pourable silicon dioxide dispersion, in which the average, number-related aggregate diameter of the silicon dioxide particles in dispersion is less than 200 nm, and which comprises at least 35 wt. % of a silicon dioxide powder, 3 to 35 wt. % of at least one polyol, 20 to 60 wt. % of water, 0 to 10 wt. % of an additive and a substance having an alkaline action in an amount such that a pH of 10
摘要:
An aqueous dispersion that can be used in the coating of glass, ceramics and metal surfaces is prepared by placing, in water, an aggregated titanium dioxide powder having a specific surface area of from 20 to 150 m2/g in such an amount that the desired dispersion contains at least 20 wt. % titanium dioxide, and at least one amino alcohol having from 1 to 6 carbon atoms, and at least one carboxylic acid selected from dibasic carboxylic acids and/or hydroxycarboxylic acids having from 2 to 6 carbon atoms. A pre-dispersion is produced by introducing energy in an amount of less than 200 kJ/m3. Then a dispersion is produced in which the aggregated titanium dioxide powder has a mean, volume-related aggregate diameter of less than 150 nm by grinding the pre-dispersion with a high-energy mill at a pressure of at least 500 bar.
摘要:
Stable, pourable silicon dioxide dispersion, in which the average, number-related aggregate diameter of the silicon dioxide particles in dispersion is less than 200 nm, and which comprises at least 35 wt. % of a silicon dioxide powder, 3 to 35 wt. % of at least one polyol, 20 to 60 wt. % of water, 0 to 10 wt. % of an additive and a substance having an alkaline action in an amount such that a pH of 10