摘要:
Process for the production of an aqueous dispersion of pyrogenically produced metal oxide and metalloid oxide powders with a BET surface area of between 5 and 600 m2/g, with a metal oxide or metalloid oxide content in the dispersion of between 5 and 25 wt. %, comprising the following steps: water, which is optionally adjusted to pH values of between 2 and 4 by adding acids, is circulated from a receiving vessel via a rotor/stator machine, and metal oxide or metalloid oxide powder is introduced, using a feed device, into the shear zone between the slots in the rotor teeth and the stator slots, continuously or discontinuously and with the rotor/stator machine running, in a quantity such that a predispersion with a solids content of between 20 and 40 wt. % results, and, after all the metal oxide powder or metalloid oxide powder has been added, the feed device closes and shearing continues in such a way that the shear rate is in the range of between 10000 and 40000 s−1, and then, by dilution, the predispersion is adjusted to the desired solids content of the dispersion while maintaining the dispersing conditions.
摘要:
Preparation for producing refractory materials, characterized in that it comprises one or more particulate, refractory components and one or more binders, where—the particulate, refractory component has a mean particle diameter of >0.3 m and—the binder is selected from among—from 0.05 to 50% by weight of a very finely particulate binder having a mean particle diameter of from 10 nm to 0.3 m selected from the group consisting of aluminum oxide, titanium dioxide, zirconium dioxide and/or mixed oxides of the abovementioned oxides, —from 0 to 20% by weight of an inorganic binder, from 0 to 20% by weight of a hydraulically setting binder, —from 0 to 15% by weight of an organic, silicon-free binder—and the preparation additionally contains from 0 to 35% by weight of water, where—the proportion of the particulate, refractory component is equal to 100 and the percentages of the further materials in the preparation are based on the particulate component.
摘要:
Process for preparing ultrafine powders based on polyamides by contacting polyamides having a relative solution viscosity ηrel in the range from 1.5 to 2.0, measured in 0.5% m-cresol solution at 25° C., with an alcoholic medium in the presence of inorganic particles suspended therein under the action of pressure and/or temperature to generate an at least partial solution, and then precipitating the polyamide from the at least partial solution; the resulting ultrafine polyamide powders have a specific BET surface area of 5-100 m2/g; a fineness d50 of less than 70 μm; an apparent density AD from 250 to 1000 g/l; and a particle content of 0.1 to 80% by weight of inorganic particles based on the total weight of the polyamide powder; which powders are equally suitable for coatings and for mouldings and components with improved mechanical properties.
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:
Dispersion containing, in addition to water, 0.5 to 20% by weight of hydrophobic silica, 0.01 to 10% by weight of a gelling additive, or viscosity-increasing additive which, as further components, contains at least one phenol or at least one phenol derivative and/or at least one aldehyde. It is prepared by dispersing the individual components successively or together in water, in which case the individual components are deaerated before and/or during the addition or the dispersion is deaerated during the individual dispersion steps and thereafter the residual air present in the dispersion is removed by application of vacuum. The dispersion can be used as insecticide and for controlling pathogenic agents.
摘要:
Preparation for producing refractory materials, characterized in that it comprises one or more particulate, refractory components and one or more binders, where—the particulate, refractory component has a mean particle diameter of >0.3 m and—the binder is selected from among—from 0.05 to 50% by weight of a very finely particulate binder having a mean particle diameter of from 10 nm to 0.3 m selected from the group consisting of aluminium oxide, titanium dioxide, zirconium dioxide and/or mixed oxides of the abovementioned oxides, —from 0 to 20% by weight of an inorganic binder, from 0 to 20% by weight of a hydraulically setting binder, —from 0 to 15% by weight of an organic, silicon-free binder—and the preparation additionally contains from 0 to 35% by weight of water, where—the proportion of the particulate, refractory component is equal to 100 and the percentages of the further materials in the preparation are based on the particulate component.
摘要:
Aqueous dispersion containing transition aluminium oxide as only solid and a dispersant, in which—the transition aluminium oxide is present in the form of aggregates of primary particles, the content of transition aluminium oxide in the dispersion is from 40 to 65% by weight, the aggregates in the dispersion have a mean aggregate diameter of less than 100 nm,—the dispersant contains polyaluminium hydroxychloride, polyaluminium hydroxynitrate and/or polyaluminium hydroxysulphate, the dispersion has a pH of from 3 to 5.
摘要:
Dispersion containing pyrogenic silicon-titanium mixed oxide powders with a silicon dioxide content of 75 to 99.99 wt.-% and a titanium dioxide content of 0.01 to 25 wt. %, water and a basic, quaternary ammonium compound, wherein the mean aggregate diameter of the particles of the silicon-titanium mixed oxide powder in the dispersion is 200 nm at most. Process for the production of a titanium-containing zeolite with the use of the dispersion.
摘要:
Aluminium oxide dispersion, which is stable in a pH range 5 from 5 to 9 and has an aluminium oxide content of at least 40 wt. %, obtainable by dispersing pyrogenically produced aluminium oxide particles in an aqueous phase, wherein one or several at least dibasic hydroxycarboxylic acids present dissolved in the dispersion and at least one salt of a 10 dialkali metal hydrogen phosphate and/or alkali metal dihydrogen phosphate are added to the aqueous phase each mutually independently in a quantity of 0.3−3×10−6 mol/m2 of aluminium oxide specific surface area.
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。