Bleaching and brightness stabilization of lignocellulosic materials with water-soluble phosphines or phosphonium compounds
US7285181B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Feb 4, 2004 |
| Grant date | Oct 23, 2007 |
| Priority date | — |
| Expiry date | Dec 4, 2024 |
Classification
- Technology area (CPC D)Textiles; Paper
- CPC primaryD21H21/32
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
A method for the bleaching and brightness stabilization of lignocellulosic materials is described. The method involves the treatment of lignocellulosic materials, in particular, (a) wood pulps such as thermomechanical pulps (TMP) and chemithermomechanical pulps (CTMP), and (b) papers made from wood pulps, with a water-soluble phosphine or a phosphonium compound preferably containing at least one phosphorus hydroxyalkyl bond/linkage, for example a phosphorus hydroxymethyl bond/linkage (P—CH2OH). One example of such a water-soluble phosphine is the commercially available, tris(hydroxymethyl)phosphine (THP), P(CH2OH)3. One example of such a phosphonium compound is the commercially available, tetrakis(hydroxymethyl)phosphonium chloride (THPC), [P(CH2OH)4]Cl.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.