Cellulose ethers and method of preparing the same
US7022837B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 31, 2001 |
| Grant date | Apr 4, 2006 |
| Priority date | — |
| Expiry date | Nov 8, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08B11/12
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present inventors have discovered that the solution rheology of cellulose ethers prepared from cellulose pulp is altered by mercerizing and recovering cellulose pulp before preparing the cellulose ethers. For example, the solution viscosity of carboxymethyl cellulose (CMC) produced from mercerized and recovered cellulose pulp is significantly greater than that produced from non-mercerized cellulose pulp. The present invention provides a method of preparing cellulose ethers comprising the steps of (a) obtaining mercerized and recovered cellulose pulp, and (b) converting the mercerized and recovered cellulose pulp into the cellulose ethers. According to one embodiment, the cellulose pulp is southern softwood kraft and the mercerized cellulose pulp has a TAPPI 230 om-89 viscosity of at most 12 cP. This method, however, may be applied to all cellulose pulps, regardless of their viscosities, including those which, when mercerized, have a viscosity greater than 12 cP. The mercerized cellulose pulp is typically substantially free of cellulose III. Mercerized cellulose pulp prepared by this method has a greater percentage of crystalline cellulose II and a smaller crystalline area than …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.