Methods for preparing alkali cellulose and cellulose ether
AssigneeShin-Etsu Chemical Co., Ltd.
InventorsMitsuo Narita, Masaki Tabata, Atsushi Yoshida, Hiroshi Umezawa
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Abstract
The invention is a method for efficiently preparing alkali cellulose having a uniform alkali distribution therein. More specifically, pulp and an excess alkali metal hydroxide solution are introduced continuously in a screw conveyor type contactor and brought into contact with each other in the screw conveyor type reactor. By changing at least one factor selected from the group consisting of a rotation speed of the screw conveyor, a screw pitch and a length of immersion zone, a ratio of an alkali to cellulose in the alkali cellulose obtained by draining is controlled. The alkali cellulose thus obtained is etherified into the corresponding cellulose ether.
Claims5
A method for preparing a cellulose ether, comprising the steps of:
- bringing pulp into continuous contact with an alkali metal hydroxide solution in a screw conveyor contactor to generate a contact mixture;
- draining the contact mixture;
- and
- etherifying the alkali cellulose prepared in the draining step with an etherifying agent to produce cellulose ether, and wherein a weight ratio of alkali metal hydroxide contained by a cake obtained in the draining step to a solid portion contained by the pulp is 0.3 to 1.5.
Dependencies are inferred from the claim text.