Finely divided polysaccharide derivatives
View Patent ↗Finely divided polysacharide derivatives are described. The finely divided polysacharide derivatives are prepared by a process comprising: a) forming an aqueous composition comprising a polysaccharide derivative and water, in which the polysaccharide derivative is soaked or dissolved; b) converting the polysaccharide derivative of the aqueous composition into finely divided solid particles by, (i) contacting the aqueous composition with superheated water vapor in a dryer-pulverizer; or (ii) causing the polysaccharide derivative of the aqueous composition to flocculate; and c) optionally drying the finely divided solid particles of step b). The primary structures of the polysaccharide starting material are largely removed, and the product has a shape factor of less than 5 and greater than or equal to 1.
1. A finely divided polysaccharide derivative product prepared by a process comprising:
a) forming an aqueous composition comprising a polysaccharide derivative and water, said composition containing water in an amount of 35 to 99 wt. %, based on the total weight of said aqueous composition, said polysaccharide derivative being soaked or dissolved in said composition;
b) converting the polysaccharide derivative of said aqueous composition into finely divided solid particles by,
(i) contacting said aqueous composition with superheated water vapor in a dryer-pulverizer, thereby converting the water of said aqueous composition into the vapor phase, and converting the polysaccharide derivative of said aqueous composition into finely divided solid particles; or
(ii) causing the polysaccharide derivative of said aqueous composition to flocculate, thereby converting the polysaccharide derivative of said aqueous composition into finely divided solid particles; and
c) optionally drying the finely divided solid particles of step b), wherein the primary structures which result from the polysaccharide starting material have been largely removed, and the product has a shape factor of less than 5 and greater than or equal to 1.
2. The polysaccharide derivative product of claim 1 , wherein it is a cellulose derivative product.
3. The polysaccharide derivative product of claim 1 , wherein it is a methyl cellulose product, methyl hydroxyethyl cellulose product, methyl hydroxypropyl cellulose product or hydroxypropyl cellulose product.
4. The polysaccharide derivative product of claim 2 wherein the polysaccharide product is a cellulose ether product.