Process and apparatus for making low molecular weight cellulose ethers
AssigneeThe Dow Chemical Company
InventorGary J. Schulz
Life of this patent
Estimating the term…
Abstract
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.
Claims13
A method of depolymerizing a high molecular weight cellulose ether powder, comprising the step of continuously tumbling the cellulose ether powder in a reactor, the reactor being rotated axially or end over end in an oven or a controlled-temperature chamber or room while simultaneously contacting the cellulose ether with a gaseous acid at a substantially isothermal level at a temperature ranging from about 50° C. to about 130° C.
Dependencies are inferred from the claim text.