Evonik Degussa Gmbh

Degussa Aktiengesellschaft

Goldschmidt Ag

Goldschmidt Gmbh

Center for Abrasives and Refractories Research & Development C.a.r.r.d. Gmbh

Dequssa Ag

Evonik Operations Gmbh

Gabriele Perlet

Wolfgang Lortz

Werner Will

Christoph Batz-Sohn

Sascha Reitz

Helmut Mangold

Heinz Lach

Gerrit Schneider

Uwe Diener

Kai Schumacher

Steffen Hasenzahl

Kathrin Lehmann

Peter Neugebauer

Klaus Jenni

Christoph Tontrup

Ralf Mathiak

Jochen Scheffler

Angela Rüttgerodt

Erich Schmidt-Kluge

Danilo Frulli

Christoph Batz-sohn

Margit Kakas

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&#x3c;pH&#x3c;12 is established. It can be prepared by a procedure in which silicon dioxide powder is introduced into water and a polyol in a rotor/stator machine, the pH being less than 5, and the mixture is dispersed until the current uptake of the rotor/stator machine is largely constant, and a substance having an alkaline action is subsequently added in an amount such that a pH of the dispersion of 10&#x3c;pH&#x3c;12 results, the substance having an alkaline reaction being added so rapidly that no gel formation takes place. It can be used as a component of a flame-retardant filling of hollow spaces between building components, in particular for insulating glass arrangements.

Silicon dioxide dispersion comprising polyol

Slurry which contains a) from (50) to (80)% by weight of refractory particles having an average particle size of from (0.5) m to (150) m, b) from (5) to (35)% by weight of aluminum oxide particles having an average particle diameter of less than (300) nm and c) from (5) to (35)% by weight of water and d) a pH of from (5) to (12). Process for producing the slurry using a dispersion, and also the dispersion itself. Process for producing a casting mold, and also the casting mold itself.

Dispersion, slurry and process for producing a casting mould for precision casting using the slurry

Aluminum oxide dispersion, which is stable in a pH range 5 from 5 to 9 and has an aluminum oxide content of at least 40 wt. %, obtainable by dispersing pyrogenically produced aluminum 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&#x2212;3&#xd7;10mol/m2 of aluminum oxide specific surface area.

Aluminium oxide dispersion

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 m/g, with a metal oxide or metalloid oxide content in the dispersion of between 5 and 25 wt. %, comprising the following steps:

Process for the production of metal oxide and metalloid oxide dispersions

Dispersion containing, in addition to water, 0.5 to 20 wt. % of hydrophobic silica, 0.01 to 10 wt. % of a gelling or viscosity-increasing additive, 0.1 to 1 wt. % of a preservative and 0 to 1 wt. % of a surface-active substance. It is prepared by a procedure in which the individual components are dispersed successively or together into the water and in this procedure the individual components are deaerated before and/or during the addition or the dispersion is deaerated during the individual dispersing steps. The dispersion can be employed as an insecticide.

Dispersion having an insecticidal action

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&#x2014;O&#x2014;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&#x2014;O&#x2014;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.

Process for preparing redispersible surface-modified silicon dioxide particles

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,&#x2014;the proportion of water is 30 to 90% by weight based on the dispersion,&#x2014;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,&#x2014;the basic composition comprises or consists of one or more amines of the general formula RNH, RNH and RN, 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,&#x2014;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,&#x2014;the pH of the dispersion being 9 to 11.

Dispersion comprising hydrophobized silicon dioxide particles

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.

Use of a cationic silicon dioxide dispersion as a textile finishing agent

Dispersion comprising water and mixed potassium silicon oxide powder, where&#x2014;the mixed oxide powder is in the form of aggregates of primary particles, has a BET surface area of 100 to 400 m/g, has an average aggregate diameter in the dispersion of less than 100 nm, and possesses a potassium fraction of 0.05% to 1.5% by weight, calculated as KO and based on the mixed oxide powder, and&#x2014;the dispersion has a fraction of mixed oxide powder in the dispersion of 25% to 40% by weight, the sum of water and mixed oxide powder is at least 98% by weight and the pH is 9 to 11.5.

Dispersion of high surface area silica

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 m/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.

Aluminium oxide-containing dispersion

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 m/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/m. 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.

Dispersion containing titanium dioxide

Aqueous dispersion which comprises hydrophobized silicon dioxide powder with a content of between 5 and 50 wt. % and which comprises at least one compound of the general formula R & supl; &#x2014;COO&#x2014;(CH2-CH(Ph)&#x2014;O)a-(CnH2n-xRx-O)b-R(I). It is prepared by dispersing the hydrophobic silicon dioxide powder, dispersing agent and optionally pH-regulating substances and further additives in an aqueous medium. It can be employed as an additive to waterborne fillers in the automobile industry, as a coating constituent in can and coil coating processes, as an additive in water-based UV-curable formulations e.g. for wood preservation and as a constituent of protective lacquer films.

Aqueous dispersion of hydrophobized silicon dioxide powder comprising a dispersing agent

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.

Aqueous dispersion containing pyrogenically prepared metal oxide particles and dispersants

An aqueous dispersion, having a silicon dioxide powder having a silicon dioxide content of 10 to 60 wt.%, wherein the aqueous dispersion is stable in the pH range of 2 to 6, the aqueous dispersion additionally contains at least one compound, which is at least partially soluble in aqueous solution in the pH range 2 to 6 in the form of polyvalent cations, these being stable in a silicate-like environment as an anionic component of the particle surface of the silicon dioxide powder, the quantity of cation-providing compound in relation to the surface of the silicon dioxide is 0.001 to 0.1 mg cation-providing compound/msilicon dioxide surface, the cation-providing compound being calculated as the oxide, and the zeta potential of the aqueous dispersion has values of less than or equal to zero.

Stabilized, aqueous silicon dioxide dispersion

An aqueous dispersion is used in the chemical mechanical polishing of surfaces, particularly oxidic surfaces, such as silicon dioxide. The aqueous dispersion contains a powder of pyrogenically produced silicon dioxide doped with 0.01 and 3 wt. % aluminium oxide, relative to the total amount of powder, said powder having an average particle diameter in the dispersion of not more than 0.1 &#x3bc;m.

Growing community of inventors

Grosskrotzenburg, Germany

Gabriele Perlet