Patent ID: 7097739
Filing Date: 2006-08-29
Classification: D21C

Abstract:
1. A method for improving properties of pulp produced, reducing the digester cycle time, or reducing the pulping or bleaching chemicals required in alkaline chemical pulping processes comprising adding to the alkaline aqueous mixture in the digester of said chemical pulping process, an effective amount of at least one compound selected from the group consisting of phosphonates having the formula: in an amount, on an active acid basis, of from about 0.03% to about 1% based upon the dry weight of the wood chips in said digester, in an amount, on an active acid basis, of from about 0.3% to about 1% based upon the dry weight of the wood chips in said digester, in an amount, on an active acid basis, of from about 0.05% to about 1% based upon the dry weight of the wood chips in said digester, or mixtures thereof; wherein M is independently selected from hydrogen, alkali metal, alkaline earth metal or ammonium, X is independently selected from H, R, —CH 2 PO 3 M 2 wherein R is an alkyl group or —NX 2 substituted alkyl group having 2 to 6 carbon atoms, R′ is an alkyl group having 1 to 17 carbon atoms and R′ is optionally branched, optionally unsaturated, and optionally substituted with SO 3 M, Y is selected from —PO 3 M 2 , H or R′, and Z is selected from —OH or —NR 1 R 2 wherein R 1 and R 2 are independently selected from hydrogen or alkyl having 1 to 2 carbon atoms.