Wolff Walsrode Ag

Dow Global Technolgoies LLC

Dow Wolff Cellulosics Gmbh

Wolff Cellulosics Gmbh Co. Kg

Wolff Cellulosics Gmbh & Co.,

Wolff Cellulosics Gmbh & Co. Kf

Hartwig Schlesiger

Jörn-Bernd Pannek

Wolfgang Dannhorn

Erik-Andreas Klohr

Martin Morning

Gunter Weber

Roland Bayer

Gerd Sonnenberg

Frank Höhl

Arne Henning Kull

Martin Kowollik

Meinolf Brackhagen

Jürgen Engelhardt

Daniel Auriel

René Kiesewetter

Werner Lange

Marco Grossstueck

Grit Grote

Volker Eckhardt

Ren&eacute; Kiesewetter

Gerolf Weissach

Rudolf Lelgemann

Rudolf Heidemann

Helmut Holste

Volkhardt Müller

Burkhard Kressdorf

Jan Zillmann

Bernhard Kranz

Marc Oliver Schmidt

Marco Großstück

Gerd Sonneneberg

Jörn Pannek

Hans-Jürgen Juhl

Grit Siegmund

Arne Kull

The present invention relates to a process for the preparation of a water-moist cellulose ether composition, characterized in that water-soluble polymeric additives which contain anionic groups (WSAP), or corresponding additive mixtures, are added to the cellulose ether composition. The invention furthermore relates to water-moist cellulose ether compositions which can be prepared by such a process, and to corresponding milled and dried cellulose ether compositions. The invention also relates to the use of these WSAP or corresponding WSAP mixtures for improving the transportability of water-moist cellulose ether compositions in conveying units.

Storing and distributing a feeder product

The present invention describes a process for preparing methylhydroxyalkylcellulose having a small number of colored particles by separation of methylhydroxyalkylcellulose from aqueous suspension with subsequent washing of the methylhydroxyalkylcellulose using a specially equipped rotary pressure filter.

Process for preparing methylhydroxyalkylcellulose having a small number of coloured particles

A description is given of glyoxal-treated polysaccharide derivatives which, to decrease the unbound glyoxal, are treated with an aqueous solution of one or more water-soluble aluminium salts, or one or more water-soluble borates, or a combination of one or more water-soluble aluminium salts and one or more water-soluble borates, and, if appropriate, with suitable buffer substances to set the pH, and then dried. A description is likewise given of a process for decreasing the content of unbound glyoxal in glyoxal-treated polysaccharide derivatives.

Water-dispersible polysaccharide derivatives of reduced glyoxal content, and a process for decreasing the glyoxal content in glyoxal-crosslinked polysaccharide derivatives

The present invention relates to a process for preparing cellulose ether products which is characterized in that superabsorbent polymers (SAPs) are dried and milled, or mill-dried, conjointly with moist cellulose ether and also to the cellulose ether products resulting from this process.

Preparation of cellulose ether products of increased viscosity and fineness

A process of preparing alkylhydroxyalkylcellulose (e.g., methylhydroxyethylcellulose and methylhydroxypropylcellulose) by reaction of cellulose in the presence of alkali metal hydroxide with an alkylating agent and a hydroxyalkylating agent is described. The process includes: (a) alkalizing cellulose by means of 0.9 to 2.9 equivalents of an alkali metal hydroxide I/AGU of the cellulose in the form of an aqueous alkali metal hydroxide solution, in the presence of a suspension medium containing at least 0.2 equivalents of an alkylating agent I/AGU of the cellulose; (b) reacting the alkalized cellulose of step (a) with alkylating agent I and a hydroxyalkylating agent at a temperature above 65&#xb0; C.; (c) adding additional alkali metal hydroxide 11 in the form of an aqueous alkali metal hydroxide solution; and (d) adding additional alkylating agent 11 in an amount of at least the absolute value of the difference between (i) the number of equivalents of alkylating agent I/AGU of the cellulose already added, and (ii) the total number of equivalents of alkali metal hydroxide/AGU of the cellulose added. Additional alkylating agent 11 is not added in step (d) if (i) the number of equivalents of alkylating agent I/AGU of the cellulose already added exceeds (ii) the total number of equivalents of alkali metal hydroxide/AGU of the cellulose already added. In a further step (e), the alkylhydroxyalkylcellulose is isolated from the reaction mixture. The isolated alkylhydroxyalkylcellulose may be optionally purified.

Process of preparing alkylhydroxyalkylcellulose

A composition comprising cellulose ether, a superplasticizer and defoamer suitable for use as an additive in extruding inorganic compositions is disclosed. The inventive composition functions as a water retention agent, plasticizer and lubricant in the extrusion of inorganic compositions. The use of the inventive composition in the extrusion of building materials leads to improved processing properties, to a higher surface quality and product properties of the extruded article.

Cellulose ether composition

The present invention relates to a new, particularly economical process for preparing particulate water-soluble cellulose derivatives. The process involves forming a feed composition of swollen and/or dissolved cellulose derivative, and water. The feed composition is contacted with a superheated gas mixture, in a sieve-free high rotational speed gas jet impact mill, and the cellulose derivative of the feed composition is converted into a solid state form of finely particulate particles. The superheated gas mixture, with which the feed composition is contacted, is selected from: (i) a superheated gaseous mixture of steam and an inert gas; and (ii) a superheated gas mixture of steam and air. The superheated gas mixture has a steam content of 40 wt. % to 99 wt. %, based on the total weight of the superheated gas mixture.

Process for producing particulate, water-soluble cellulose derivatives using a superheated gas mixture containing steam

A method of preparing construction material systems is described. The process includes extruding a composition of construction materials and an irreversibly crosslinked cellulose derivative that is prepared by a particular process.

Process for cement extrusion that makes use of crosslinked cellulose additives

A process for preparing cellulose ethers having delayed dissolution in water is described. The process comprises: (a) treating a moist cellulose ether with a solution comprising a dialdehyde; (b) adding an aqueous salt solution to the moist cellulose ether, such that said cellulose ether has a pH of from 6.0 to 8.0, the aqueous salt addition being performed at least one of, (i) prior to step (a), (ii) concurrently with step (a), and (iii) subsequent to step (a); and (c) drying and comminuting the treated cellulose ether of step (b). The cellulose ether, or mixtures of cellulose ethers, prepared by the method of the present invention may be used as protective colloids, thickeners and adhesives.

Process of preparing delayed-dissolution cellulose ethers

A description is given of cellulose derivatives having gel-like rheological properties in aqueous solution characterized in that:

Cellulose derivatives having gel-like rheological properties and process for the preparation thereof

Described is a building material composition prepared from or having added thereto a particulate material selected from particulate polysaccharides or particulate polysaccharide derivatives. The particulate material of the building material composition is prepared by a method comprising: (a) forming a feed composition comprising a member selected from the group consisting of polysaccharides and polysaccharide derivatives, and 35 wt. % to 99 wt. % of water, based on the total weight of the feed composition, wherein said member is at least one of swelled and dissolved in the feed composition; (b) contacting, in a mill, the feed composition with a gas stream, thereby converting simultaneously the water of said feed composition into water vapor, and said member of said feed composition into a solid state form of finely particulate material; (c) separating the particulate material from the gas stream; and (d) optionally drying the particulate material. Examples of building material compositions according to the present invention include tile adhesives and joint fillers.

Building material compositions

A process for preparing low-viscosity water-soluble cellulose ethers by the oxidative decomposition of higher-viscosity cellulose ethers with hydrogen peroxide is described. The process involves: (a) forming, under conditions of intensive mixing and at temperatures of 65-125&#xb0; C., a mixture of, (i) one or more higher-viscosity cellulose ethers, and (ii) an aqueous solution of hydrogen peroxide, the proportions of the mixture being selected in such a way that the hydrogen peroxide content is 0.1-10 wt. % in relation to the dry cellulose ether, the solids content of the mixture is at least 25 wt. % in relation to the total weight of the mixture; and (b) agitating continuously the mixture of step (a) at temperatures of 65-125&#xb0; C. until at least approximately 90% of the hydrogen peroxide has been spent.

Method for the production of low-viscous water soluble cellulose ethers

Described is a process of preparing alkylhydroxyalkyl cellulose, e.g., methylhydroxypropyl cellulose (MHPC). The process includes: (a) alkylating cellulose with an aqueous caustic solution containing from 1.5 to 5.5 equivalents of alkali metal hydroxide, e.g., NaOH, per anhydroglucose unit (AGU) of said cellulose, in the presence of a suspension agent, e.g., dimethyl ether, which contains alkyl halide, e.g., methyl chloride, in an amount of from (equivalents of alkali metal hydroxide per AGU minus 1.4) to (equivalents of alkali metal hydroxide per AGU plus 0.8); (b) reacting the alkalised cellulose of step (a) with one or more alkylene oxides, e.g., propylene oxide, at a temperature higher than 65&#xb0; C., e.g., 85&#xb0; C.; (c) adding alkyl halide, to the product of step (b), in an amount of at least the difference between (i) the equivalents of alkyl halide per AGU in step a) and (ii) the equivalents of alkali metal hydroxide added per AGU in step (a), provided that the amount of additionally added alkyl halide is at least 0.2 equivalents per AGU; and (d) isolating alkylhydroxyalkyl cellulose from the reaction mixture of step (c). Optionally the isolated alkylhydroxyalkyl cellulose may be purified.

Process for preparing alkylhydroxyalkyl cellulose

A process of both milling and drying a solvent-moist material (e.g., water-moist methylhydroxyethylcellulose) is described. The process includes, (a) providing a mill-dryer () which includes, in series, a heat exchanger (), a mill () and a particulate separating apparatus () connected by conduits (), () and (), which together define a mill-dryer circuit (). The mill-dryer () also includes a bypass conduit (), which provides optionally at least partial gaseous bypass of the heat exchanger (). The process further includes: (b) introducing the solvent-moist material into the mill (); (c) circulating a vapor stream (e.g., a steam/air stream) throughout the mill-dryer circuit (); (d) heating the vapor stream by means of passage through the heat-exchanger (); (e) forwarding milled particulate material from the mill () to the particulate separating apparatus () by means of conduit (); (f) separating the particulate material from the vapor stream in the particulate separating apparatus (); (g) forwarding the vapor stream from the particulate separating apparatus () through conduits (); and (h) controlling the temperature of the vapor stream by optionally forwarding at least some of the vapor stream through the bypass line ().

Process and apparatus for combined milling and drying

The present invention relates to a new, particularly economical process for producing particulate water-soluble cellulose derivatives. The process involves forming a feed composition of swollen and/or dissolved cellulose derivative, and water. The feed composition is contacted with a carrier and heat exchange gas, in a sieve-free high rotational speed gas jet impact mill, and the cellulose derivative of the feed composition is converted into a solid state form of finely particulate particles. The particulate cellulose derivative is then separated from the heat exchange gas and carrier gas, and optionally dried. The mill drying and the particulate cellulose derivative product are influenced by establishing a specific water content in the swollen and/or dissolved cellulose derivative.

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Fallingbostel, Germany

Hartwig Schlesiger