Patent ID: 8501841
Filing Date: 2013-08-06
Classification: C08L

Abstract:
1. A method of manufacturing an aqueous bonding resin, the method comprising: in a first stage, reacting phenol with formaldehyde in the presence of a kraft liquor degraded lignin polymer that is substantially free of sulfonic acid groups, water, and a group 1 alkaline metal hydroxide; wherein the reaction product of the phenol and formaldehyde are 40 to 85% of the weight of the solids in the aqueous bonding resin and the mole ratio of formaldehyde to phenol is 1.5-3.5:1; the group 1 alkaline metal hydroxide is 5 to 20% of the weight of the solids in the aqueous bonding resin; and the kraft liquor degraded lignin polymer is 5 to 20% of the weight of the solids in the aqueous bonding resin; reacting the ingredients at a temperature of 60-100° C. until the viscosity of the mixture is 200-5000 cps; in a subsequent second stage, cooling the mixture to a temperature less than 60° C.; and thereafter adding urea to the first stage reaction product until the viscosity is 50-1000 cps while maintaining the reaction temperature at less than 60° C.