Patent ID: 7642306
Filing Date: 2010-01-05
Classification: G05D

Abstract:
1. A method of controlling the pH of a formaldehyde-free aqueous binder composition comprising: preparing a mixture of a formaldehyde-free resin and water; adding a pH control agent to the mixture; measuring the pH of the mixture after the addition of pH control agent; electrically relaying the pH measurement to a PID system; comparing the measured pH with a pre-set pH value; adjusting the amount of pH control agent added to the mixture when the measured pH varies from the pre-set pH value by ± about 0.3 pH units such that the pH value of the mixture equals the pre-set pH value ± about 0.3 pH units and where the preset pH value is less than or equal to about 3.5, wherein the formaldehyde-free aqueous resin further comprises more than one acidic functional groups selected from the group consisting of carboxy, anhydride, carboxy salts and anhydride salts, wherein the formaldehyde-free aqueous binder composition further comprises a polyol having at least two hydroxyl groups, wherein the ratio of acidic functional groups to hydroxyl groups ranges from about 1:1.1 to 1:3.