The Dow Chemical Company

Gary J Schulz

Steven Rosenberg

Colin M Keary

Daniel A Alderman

Susan M Kling

Kenneth C Reibert

Stephen B Christensen

Michael R Smith

Michael V Spencer

A process for making a low molecular weight cellulose ether has the following steps: a) providing a high molecular weight cellulose ether; b) contacting it with acid to partially depolymerize it to a cellulose ether of a viscosity of about 100 cP or less; c) neutralizing the acid; d) repeating steps a)-c) to produce two or more discrete product batches of low molecular weight cellulose ether and produce at least one discrete product batch which is partially neutralized; and e) blending the two or more discrete product batches to form a combined product batch of low molecular weight cellulose ether of a pH of 4 to 6.8. The process provides a cellulose ether with reduced yellowing and discoloration.

Process for making cellulose ethers having reduced yellowing and discoloration

Disclosed is a cellulose ether composition having a low molecular weight cellulose ether of a viscosity of about 200 centipoise or less in a two percent aqueous solution at 20&deg; C. The composition has a sodium chloride content of about 0.3 weight percent or less based upon the weight of the cellulose ether. The composition exhibits significantly reduced haze formation when in capsule form. Also disclosed is a process for making the composition.

Haze-free cellulose ether capsules and process for making

There is a process for making a cellulose ether. The process comprises the following: a) alkalyzing a cellulose pulp; b) etherifying the alkalyzed cellulose pulp to form a cellulose ether; c) washing the cellulose ether; d) drying the cellulose ether; e) milling the cellulose ether to a particulate form; f) heating the particulate cellulose ether; g) tumbling the particulate cellulose ether while simultaneously contacting it with an acid to partially depolymerize it to a lower molecular weight; h) partially or substantially neutralizing the acid. There is also an apparatus for making the cellulose ether.

Process and apparatus for making low molecular weight cellulose ethers

An improved process for surface treating water soluble cellulosic polymers with crosslinking agents to provide products which are more readily dispersible in cold water, and have longer viscosity delay times than can be achieved with polymers treated in low intensity mixers, such as ribbon blenders, comprising distributing the crosslinking agent using a continuous, high intensity mixer, followed by heating to facilitate surface crosslinking. This process also allows for a reduced level of crosslinking chemicals to be used.

Process for preparing readily dispersible water-soluble cellulosic

This invention is a process for comminuting a cellulose ether which comprises extruding a hydrated cellulose ether through a plurality of orifices, each orifice having a cross-sectional area of from about 7.5.times.10.sup.-9 m.sup.2 to about 1.times.10.sup.-6 m.sup.2, to form an elongated extrudate, and then cutting the elongated extrudate to desired length. The high density cellulose ether product is typically cold water dispersible, non-dusty, and free flowing.

Process for comminuting cellulose ethers

This invention is a process of removing water-soluble impurities from a water-soluble cellulose ether aqueous solution containing such water-soluble impurities comprising treating an aqueous solution comprising a water-soluble cellulose ether and a water-soluble impurity by means of ultrafiltration and diafiltration at conditions effective to produce a treated aqueous solution having a reduced concentration of the water-soluble impurity and an increased concentration of the water-soluble cellulose ether.

Removal of undesirable material from water-soluble cellulose ether

Palatable cholestyramine granules, tablets and method for preparation thereof are disclosed.

Palatable cholestyramine granules, tablets and methods for preparation

A method of removing undesirable material from water-soluble polysaccharide ethers, such as water-soluble cellulose ethers, via contact of an aqueous solution of the water-soluble polysaccharide ether with an anion exchange resin. Anion exchange resins that are useful in the invention are derived from epoxy resin polymers, acrylic based copolymers or a copolymer of styrene-divinylbenzene. The method significantly reduces the amount of colored bodies in the polysaccharide ether.

Removal of undesirable material from water-soluble polysaccharide ethers

High viscosity cellulose ether products are produced by grinding a substantially dry high molecular weight cellulose ether under conditions of mild mechanical impact such as those encountered in a high speed air swept impact mill. It has been found that such a cellulose ether product has several times the intrinsic viscosity of a product of substantially equivalent particle size by ball mill or hammer mill grinding.

Grinding process for high viscosity cellulose ethers

A method of making a cold water dispersible granular composition comprising a plasticizer and thermally moldable polymer, for example hydroxypropyl methylcellulose, hydroxypropyl cellulose, carboxymethylcellulose, or hydroxy ethylcellulose. The method comprises, extruding the composition at elevated temperatures to form an extruded material and grinding the extruded material to form a granular product. The granules are very dispersible in cold water and when added to cold water, the solution can be used in coating operations, such as to coat pharmaceuticals, foods and food supplements to protect, color, harden, make foods more palatable or mask the taste of solid dosage forms.

Method of making a granular, cold water dispersible coating composition

Impurities in cellulose ether compositions are removed by providing a functionally effective thickness of a cellulose ether composition to a filtration device, and contacting the thickness, in a manner such that substantial thickness is maintained with at least one extracting solution in which the impurities in the cellulose ether are soluble such that a gradient impurity concentration is formed. High purity cellulose ethers are prepared, without experiencing large product losses.

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Midland, MI, United States of America

Gary J Schulz