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AssigneeBetz PaperChem, Inc.
InventorsMichael M. Blackstone, Cheng-I Chen, Thomas W. Woodward
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The present invention is directed to the use of certain ethoxylated compounds to increase the yield of chemical pulping processes, the compound have the following structures: ##STR1## These ethoxylated compounds have molecular weights of from about 500 to about 30,000 the (CH.sub.2 CH.sub.2 O) comprising from about 20 to 80 percent of the compound; and a, b, and c are each at least 1. The compounds are surface active agents which are added to the cooking liquor. The wood chips are cooked from about one-half and ten hours at a temperature of from about 200 and 500 degrees Fahrenhelt in a liquor including sodium hydroxide, sodium sulfide, and the surface active agent. The wood plug would have a reject level of at least 5% when the chips are cooked in the absence of the surface active agent. The process provides a simultaneous reduction in the level of rejects and an increased yield of pulp.
An improved process for cooking wood chips in a cooking liquor to form a Kraft pulp, the process comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Other features of pulping processes: use of compounds accelerating the pulping processes
Production of cellulose by removing non-cellulose substances from cellulose-containing materials
Term ended 6 Mar 2007 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to the production of wood pulp by the sulfate pulp process. The technology and objectives of the present invention are described in detail in U.S. Pat. No. 3,909,345, the disclosure of which is incorporated in its entirety herein by reference.
The '345 patent discusses and claims the use of surface active agents having the general formula
R[(C.sub.2 H.sub.4 O).sub.n (C.sub.3 H.sub.6 O).sub.m)]yH
The following laboratory and mill studies and results demonstrate the effectiveness of certain surfactants and blends thereof as pulping additives to cooking liquor.
A product comprised on an active basis of an aqueous solution containing 10% Pluronic L-62 and 71/2% Pluronic F-108 was tested. The mill produced Kraft pulp utilizing Southern Pine chips being cooked (pulped) at the following conditions
Active Alkali=15% as Na.sub.2 O in cooking liquor