Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From lignin – tannin – or derivative reactant
Patent
1990-02-20
1991-06-04
Nielsen, Earl
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From lignin, tannin, or derivative reactant
530501, 530507, 527403, C08H 502
Patent
active
050215310
ABSTRACT:
Lignin, or a lignin derived material, which has been significantly demethylated (e.g., the demethylated lignin found in the raffinate produced as a by-product of dimethyl sulfide production which can be carried out using the spent liquor from wood pulping operations) can be isolated by a process wherein an organic solvent is added to a lignin-containing aqueous solution. The organic solvent is typically a polar, and at least a partially water-immiscible substance such as, for example, ethyl acetate. The resulting lignin-containing aqueous solution/organic solvent mixture is acidified to produce a water layer which is discarded and an organic solvent layer which contains the demethylated lignin. Upon its recovery, the demethylated lignin is preferably dried and stored until it is used (along with an alkali, an aldehyde and an adhesive filler) in compounding an adhesive of the type generally used in the manufacture of plywood.
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Colorado State University Research Foundation
Krass Frederick
Nielsen Earl
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