Bleaching and brightness stabilization of lignocellulosic materials with water-soluble phosphines or phosphonium compounds
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United States of America Patent
Stats
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Oct 23, 2007
Grant Date -
Sep 9, 2004
app pub date -
Feb 4, 2004
filing date -
Feb 5, 2003
priority date (Note) -
Expired
status (Latency Note)
Importance
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--CH.sub.2OH). One example of such a water-soluble phosphine is the commercially available, tris(hydroxymethyl)phosphine (THP), P(CH.sub.2OH).sub.3. One example of such a phosphonium compound is the commercially available, tetrakis(hydroxymethyl)phosphonium chloride (THPC), [P(CH.sub.2OH).sub.4]Cl.
First Claim
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