Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – With chemical or physical modification of liberated fiber
Patent
1990-07-20
1992-01-14
Chin, Peter
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
With chemical or physical modification of liberated fiber
162 72, 162 76, 162150, 1621576, 162158, 162160, 1621812, D21C 900
Patent
active
050807544
ABSTRACT:
A method and article of manufacture thereof is provided for reducing brightness reversion in bleached lignin-containing pulps or newsprint by the treatment of the bleached lignin-containing pulp or newsprint with a compound which donates a hydrogen atom to a photo-excited group or free radical more easily than does the lignin contained in the treated pulp. The hydrogen donating compounds include compounds with certain formyl functionality, including formate salts such as sodium, magnesium and calcium formate, formamides, formic acid esters, and formylurea. In one embodiment, calcium carbonate is added to enhance the activity of the formyl compound. The further addition of a trace amount of superoxide anion quencher such as copper sulfate or ascorbic acid is also provided to still further enhance the activity of the formyl compound, especially formate salts.
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Alexander Thomas C.
Dence Carlton W.
Francis Raymond C.
Chin Peter
The Research Foundation of State University of NY
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