The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 19, 1992
Filed:
Mar. 19, 1991
Applicant:
Inventors:
Richard Burley, Derby, GB;
Patrick Roche, Derbyshire, GB;
Assignee:
Courtaulds PLC, , GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C08B / ; D21C / ;
U.S. Cl.
CPC ...
162-9 ; 162 23 ; 162 76 ; 1621576 ; 536 69 ; 536 70 ; 536 71 ;
Abstract
A process for making cellulose acetate from wood pulp takes wet wood pulp and instead of converting it into dry pulp sheet which is the usual feedstock for acetate, dries and mechanically separates the pulp into a cellulose flock using a pin mill through which a hot drying gas is passed. Deactivation of the cellulose is avoided by control of the drying gas exit temperature to 80.degree. C. to 95.degree. C. and of the moisture content of the cellulose flock to 4 to 15% by weight. The flock produced may be acetylated directly without any need for reactivation treatments additional to the normal activation with acetic acid.