Paper making and fiber liberation – Processes of chemical liberation – recovery or purification... – Waste paper or textile waste
Patent
1981-08-04
1983-10-25
Smith, William F.
Paper making and fiber liberation
Processes of chemical liberation, recovery or purification...
Waste paper or textile waste
162 8, 162 13, 162 82, 162 83, 162 90, 162129, D21C 502, D21C 900
Patent
active
044117370
ABSTRACT:
An improvement in a method for producing paper is disclosed. The paper-producing method involves the steps of preparing a slurry of high lignin content having a predetermined freeness and containing from 1 to 20 percent by weight of fibers, refining the slurry to enable the production therefrom of paper having predetermined properties, forming a web from the slurry and drying the web. The improvement involves treating the high lignin content slurry, prior to the refining step, with a sodium, potassium or lithium alkaline sulfite/sulfide/carbonate solution at atmospheric pressure at a temperature of at least 60.degree. C. and at a pH of at least 10 for from 10 to 60 minutes. The amount of the sulfite/sulfide/carbonate solution should be sufficient that the treatment increases the strength of paper made at the same degree of freeness. The slurry should be one in which at least 50 percent of the fibers are softwood fibers and containing not more than 3.0 percent of residual cooking chemicals.
REFERENCES:
patent: 1921539 (1933-08-01), Richter
patent: 4145246 (1979-03-01), Goheen et al.
USDA Forest Service, P. Koch, Agriculture Handbook #420, 8/72, pp. 1436-1438, 1443.
H. J. Kvisgaard, "Ettersulfonering", Norsk Skogindustri, 4/65, pp. 155-163.
H. E. Worster, "The Present and Future of Alkaline Pulping", Pulp & Paper Canada, vol. 75, #10, 10/74, pp. 480-485.
K. P. Kringstad et al., "Sulphonation of High Yield Kraft Pulp", Svensk Papperstidning No. 13, 1974, pp. 480-485.
H. E. Worster et al., "Increased Linerboard Pulp Yield Through Sulfonation", TAPPI, vol. 58, No. 11, pp. 117-119.
Click M. E.
Nelson J. R.
Owens--Illinois, Inc.
Smith William F.
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