US 4,902,792 A · Fine cellulose particles and process for production thereof

Abstract

A process for producing fine cellulose particles, which comprises (1) mixing viscose with a water-soluble anionic polymeric compound or polyethylene glycol or its derivative to form a dispersion of fine particles of viscose, (2) (i) heating the dispersion or mixing it with a coagulating agent to thereby coagulate the viscose in the dispersion, and thereafter neutralizing it with an acid to form fine particles of cellulose, or (ii) coagulating and neutralizing the dispersion with an acid to form fine particles of cellulose, and (3) thereafter, separating the fine particles of cellulose from the motor liquor. The fine cellulose particles (a) are composed substantially of II-type cellulose, (b) have a crystallinity, of 5 to 35% by weight, (c) are composed substantially of particles of not more than 20 micrometers, and (d) have a sharp particle size distribution.

Claims42

Dependent claims

A process for producing fine cellulose particles, which comprises

(1) mixing viscose with a water-soluble anionic polymeric compound and forming a dispersion of fine droplets of the viscose dispersed in an aqueous mother liquor,
(2) (i) heating the dispersion without drying it or mixing it with a coagulating agent to thereby coagulate the viscose in the dispersion, and thereafter neutralizing the dispersion with an acid to form fine particles of cellulose dispersed in said aqueous mother liquor, or (ii) coagulating and neutralizing the dispersion with an acid to form fine particles of cellulose dispersed in said aqueous mother liquor, and
(3) thereafter, separating the fine particles of cellulose from said aqueous mother liquor.

Dependencies are inferred from the claim text.

Fine cellulose particles and process for production thereof

Life of this patent

Fine cellulose particles and process for production thereof

Life of this patent

Abstract

Claims42