摘要:
An aqueous dispersion for use as a finishing agent for textiles, wherein the dispersion contains a pyrogenically produced, aggregated silicon dioxide powder and a cationic polymer which is soluble in the dispersion, wherein the cationic polymer is present in a quantity such that the particles of the silicon dioxide powder exhibit a positive zeta potential.
摘要:
A method and device for producing a finely divided dispersion of solids having a mean particle size of 10 nm to 10 µm, in which at least two flows of a predispersion are sprayed by means of pumps, preferably high-pressure pumps, through one nozzle each into a grinding chamber enclosed by a reactor housing onto a collision point, wherein the grinding chamber is flooded with the predispersion and the finally divided dispersion is removed from the grinding chamber by the overpressure of the predispersion continuing to flow into the grinding chamber.
摘要:
Powder consisting of particles with a core of titanium dioxide and a coating of silicon dioxide, which powder has a content of silicon dioxide of between 0.5 and 40 wt. %, a BET surface of between 5 and 300 m2/g, and which consists of primary particles that have a coating of silicon dioxide and a core of titanium dioxide. The powder is produced according to a process in which a vaporisable silicon compound and a vaporisable titanium compound are mixed corresponding to the subsequently desired ratio of SiO2 and TiO2 in the product, are vaporised at temperatures of 200° C. or less, and conveyed by means of an inert gas stream together with hydrogen and air or with oxygen-enriched air to the central pipe (core) of a known burner, the reaction mixture is ignited at the mouth of the burner and introduced together with secondary air, is combusted in a cooled flame pipe, following which the titanium dioxide powder coated with silicon dioxide is separated from the gaseous reaction products and if necessary is freed in moist air from adhering hydrogen chloride, the ratio of primary air to secondary air being greater than 0.3, the ratio of core hydrogen to secondary air being greater than 1, and the ratio of titanium dioxide precursor to secondary air being greater than 0.5. Sunscreen agent containing the powder in an amount of between 0.01 and 25 wt. %.
摘要:
A pyrogenic process is used to prepare alkali-doped silica particles. Particles produced by this process exhibit homogeneous doping, reduced agglomeration, greater stability and higher removal rates. Aqueous dispersions containing alkali-doped pyrogenic silica with average particle size less than 100 nm are used for polishing surfaces (CMP).
摘要:
The invention relates to a process for the preparation of organosilylalkylpolysulfanes, of the general formula I (R1R2R3SiR4)2Sx (I) by reaction of organosilylalkylpolysulfanes of the general formula II (R1R2R3SiR4)2Sy (II) with an ionic sulfide of the general formula M+2S2− (III) and an organosilylalkyl halide of the general formula R1R2R3SiR4X (IV), the long-chain organosilylalkylpolysulfane of the general formula (II) and the organosilylalkyl halide of the general formula (IV) being initially introduced into the reaction vessel and the ionic sulfide of the general formula (III) being added to this solution in several portions.
摘要翻译:本发明涉及制备通式Ⅰ(R1R2R3SiR4)2Sx(Ⅰ)的有机甲硅烷基烷基聚硫烷的方法,通过使通式II(R1R2R3SiR4)2Sy(Ⅱ)的有机甲硅烷基烷基聚硫与通式M + 2SII(III)和通式为R 1 R 2 R 3 SiR 4 X(IV)的有机甲硅烷基烷基卤化物,通式(II)的长链有机甲硅烷基烷基聚 硫烷和通式(IV)的有机甲硅烷基烷基卤化物最初引入反应容器中, 将通式(III)的离子性硫化物分几部分加入到该溶液中。
摘要:
Process for preparing a dispersion comprising silicon dioxide particles and cationizing agents, by dispersing 50 to 75 parts by weight of water, 25 to 50 parts by weight of silicon dioxide particles having a BET surface area of 30 to 500 m2/g and 100 to 300 μg of cationizing agent per square meter of the BET surface area of the silicon dioxide particles, wherein the cationizing agent is obtainable by reacting at least one haloalkyl-functional alkoxysilane, hydrolysis products, condensation products and/or mixtures thereof with at least one aminoalcohol and water; and optionally removing the resulting hydrolysis alcohol from the reaction mixture. Also the process for preparing the dispersion, wherein the cationizing agent comprises one or more quaternary, aminoalcohol-functional, organosilicon compounds of formula III and/or condensation products thereof, wherein Ru and Rv are independently C2-4 alkyl group, m is 2-5 and n is 2-5.
摘要:
Process for preparing a dispersion comprising silicon dioxide particles and cationizing agents, by dispersing 50 to 75 parts by weight of water, 25 to 50 parts by weight of silicon dioxide particles having a BET surface area of 30 to 500 m2/g and 100 to 300 μg of cationizing agent per square metre of the BET surface area of the silicon dioxide particles, wherein the cationizing agent is obtainable by reacting at least one haloalkyl-functional alkoxysilane, its hydrolysis products or condensation products and/or a mixture thereof with at least one aminoalcohol and a defined amount of water and optionally removing the resulting hydrolysis alcohol at least partly from the reaction mixture.Process for preparing a dispersion comprising silicon dioxide particles and cationizing agents, by dispersing 50 to 75 parts by weight of water, 25 to 50 parts by weight of silicon dioxide particles having a BET surface area of 30 to 500 m2/g and 100 to 300 μg of a cationizing agent per square metre of the BET surface area of the silicon dioxide particles, wherein the cationizing agent comprises one or more quaternary, aminoalcohol-functional, organosilicon compounds of the general formula III and/or condensation products thereof, wherein Ru and Rv are each independently of each other an alkyl group having 2 to 4 carbon atoms, m is 2 to 5 and n is 2 to 5.
摘要:
The invention relates to a composition and to a method for the production thereof, comprising quaternary amino-functional organosilicon compounds, in particular in the form of oligomers and polymers, which can be present ranging from partially hydrolyzed form to completely hydrolyzed form, and which are in particular soluble in water, have a low VOC content, and to the use thereof.
摘要:
Process for preparing an aluminium oxide powder which is present in the form of aggregated primary particles and comprises at least 85% by weight of alpha-aluminium oxide, in which an aluminium oxide powder which a) is present in the form of aggregated primary particles, b) is selected from the group consisting of gamma-aluminium oxide, theta-aluminium oxide, delta-aluminium oxide and/or X-ray amorphous aluminium oxide, and c) has a tamped density of at least 250 g/l, is subject to a heat treatment at 13000C or more and subsequently milled. Aluminium oxide powder which can be obtained by this process. Aluminium oxide powder in the form of aggregated primary particles having a BET surface area of from 3 to 30 m2/g, in which the proportion of alpha-aluminium oxide is at least 85% by weight and the ratio dgo/dio of the weight distribution of the primary particles is at least 2.8. Use as constituent of fluorescent tubes.
摘要:
An aqueous dispersion containing pyrogenically prepared oxide particles of titanium, zinc, iron or cerium with an average particle size, expressed as the median, in the dispersion of less than 250 nm, that the particle sizes of the oxide particles in the dispersion are not distributed symmetrically and the dispersion contains, as a dispersant, at least one compound of the formula (I) and/or a maleic anhydride/acrylate copolymer of the general formula (IIa) and/or a maleate/acrylate copolymer of the general formula (IIb). It is prepared by dispersing a predispersion stream by means of a high energy mill. It can be used in sunscreen formulations.