The Dow Chemical Company

Maurice L Zweigle

Jack C Lamphere

Janet C Hickman

Samuel J Kasley

Daniel A Alderman

Compositions capable of the sustained release of active organic agents are made from an aqueous dispersion of a water-insoluble cellulose ether which cellulose ether particles have reversibly diffused therein the active agent. The dispersions may be used as dispersions, dewatered to form a powder, or coalesced to form films or other articles all of which are capable of sustained release of the active agent.

Sustained release compositions

Dispersions capable of the sustained release of active organic agents comprising an aqueous dispersion of a water-insoluble cellulose ether which cellulose ether particles have reversibly diffused therein the active agent. The dispersions may be used as dispersions, dewatered to form a powder, or coalesced to form films or other articles all of which are capable of sustained release of the active agent.

A cellulosic composition of a cellulosic such as ethyl cellulose, a surfactant such as polyoxyethylene sorbitan monolaurate and a heat stabilizer such as triaryl phosphite can be mixed with an oil extender to form a hot melt composition which does not discolor upon extended heating at elevated temperatures.

Cellulosic compositions useful in preparing hot melts

An aqueous dispersion of colloidal size particles of a water-insoluble, polysaccharide derivative such as ethylcellulose is prepared by grinding the water-insoluble, polysaccharide derivative in the presence of water. A suspending agent is optionally employed to increase grinding efficiency and to form a stable suspension of the colloidal size particles.

Preparing an aqueous dispersion of colloidal size particles of a

Hot melt compositions of a cellulosic such as ethyl cellulose, an oil extender and a compatibilizing amount of a surfactant such as polyoxyethylene sorbitan monolaurate exhibit (1) reduced oil exudation and/or (2) increased compatibility of the components in said composition.

Hot melt compositions

In the preparation of organosoluble cellulose ethers, the content of alkali metal (hydroxides and the salts thereof) in the resulting cellulose ether is reduced by forming a solution of the cellulose ether and an organic solvent, converting the alkali metal hydroxide therein to an alkali metal salt and heating the resulting solution at conditions sufficient to (1) increase the size of the alkali metal salt particles and (2) remove any water therefrom. Filtering the resulting mixture and drying the filtrate yields a cellulose ether containing a very small percentage of alkali metal salt, e.g., often less than about 500 ppm.

Purification of cellulose ether reaction product

Discrete, spheroidal microgels of a water-swollen or water-swellable, cross-linked polymer such as cross-linked polyacrylamide are particularly useful as thickening agents for aqueous dispersions to be subjected to high shear and as agents for reducing the permeability of porous structures.

Cross-linked, water-swellable polymer microgels

A concentrated solution of a water-soluble vinyl monomer is mixed at or below room temperature with an effective amount of a peroxygen catalyst and the resulting solution is freed of inhibitory oxygen and thereafter atomized into a reaction vessel containing an atmosphere of gaseous sulfur dioxide to produce a polymer product by redox catalysis.

Method for preparing polymers from water soluble vinyl monomers

In the preparation of polyquaternary ammonium salts by alkylation of polymers of water-soluble ethylenically unsaturated amines such as a dialkylamino methylacrylamide with a quaternizing agent such as an alkyl halide in an aqueous solution of the polymer, more rapid and complete alkylation is obtained when the reaction is carried out in an acidic medium containing a lower alkanol such as methanol.

Method for quaternizing polymers of water-soluble aminovinyl monomers

Cross-linked water-swellable polymers are described, having a particle size of less than 4 microns. They are used as thickening agents for aqueous dispersions or solutions, particularly useful where high shear conditions are encountered in the application.

Cross-linked water-swellable polymer particles

In the preparation of polyquaternary ammonium salts by alkylation of a dialkylaminomethylacrylamide polymer with an alkyl halide in an aqueous solution of the polymer, more rapid and complete alkylation is obtained when the reaction is carried out in an acidic medium containing a lower alkanol such as methanol.

Method for alkylating aminomethylacrylamide polymers

A concentrated solution of a water-soluble vinyl monomer is mixed at or below room temperature with an effective amount of a peroxide catalyst and the resulting solution is freed of inhibitory oxygen and thereafter atomized into a reaction vessel containing an atmosphere of gaseous sulfur dioxide to produce a polymer product by redox catalysis.

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Midland, MI, United States of America

Maurice L Zweigle