Freeze dried, cross-linked microfibrillated cellulose
AssigneeMcNeil-PPC, Inc.
InventorsKambiz B. Makoui, Pronoy K. Chatterjee
Life of this patent
Estimating the term…
Abstract
Absorbent retentive pulp is described which is capable of retaining good absorbency even after having been highly compressed. The pulp is produced by mixing a microfibrillated pulp slurry with a cross-linking agent followed by freeze drying.
Claims29
An absorbent product comprising, as an absorbent element therein, wet cross-linked and freeze dried microfibrillar pulp, said pulp comprising sheets of microfibrils arranged as discontinuous walls surrounding void volumes, said microfibrils having intermolecular cross-links between macromolecular chains, said absorbent element retaining good absorbency even after having been highly compressed to a sample density of at least 0.1 lg/cm.sup.3.
A process for preparing a highly absorbent retentive cellulose pulp, said pulp being capable of retaining good absorbency even after having been highly compressed to a sample density of at least about 0.1 g/cm.sup.3, said process comprising:
- (a) forming a slurry, in a freeze drying medium, of cellulose fibers which have been beaten to a degree such that at least the outermost secondary walls thereof are essentially completely disintegrated into microfibrillar form, said freeze drying medium consisting of water or a non-aqueous solvent which is capable of hydrogen bonding with cellulose and which in pure form possesses a freezing point between 0.degree. C. and 100.degree. C., or a boiling point between 0.degree. C. and 150.degree. C. at normal pressure:
- (b) adding a cross-linking agent to said slurry and permitting cross-linking to commence;
- and
- (c) freeze drying said slurry;
- whereby said highly absorbent, retentive, cross-linked cellulose pulp results.
Dependencies are inferred from the claim text.