Bleach Stabilizer Compositions And Methods

Abstract

Compositions for and methods of stabilizing bleaching and making paper or paperboard having suitable brightness are provided. A stabilizer composition is provided containing aminocarboxylate, hydroxy acid, and either polyamino acid or iminodisuccinate, or both. The stabilizer composition can have low levels or be free of magnesium, phosphates, and silicates. The present invention also relates to a method of stabilizing the bleaching of pulp at an alkaline pH.

What is claimed is: 
     
         1 . A stabilizer composition comprising:
 a) about 50 wt % to about 80 wt % of at least one aminocarboxylate;   b) about 5.0 wt % to about 20 wt % of at least one hydroxy acid;   c) about 1.0 wt % to about 10 wt % of at least one polyamino acid, at least one iminodisuccinate, or both,   wherein a), b), and c) are different from each other, and wherein each wt % is based on the total weight of the stabilizer composition.   
     
     
         2 . The stabilizer composition of  claim 1 , further comprising water. 
     
     
         3 . The stabilizer composition of  claim 1 , further comprising less than 0.05 wt % magnesium based on the total weight of the stabilizer composition. 
     
     
         4 . The stabilizer composition of  claim 3 , further comprising less than 0.0001 wt % magnesium based on the total weight of the stabilizer composition. 
     
     
         5 . The stabilizer composition of  claim 4 , wherein the stabilizer composition is free of magnesium. 
     
     
         6 . The stabilizer composition of  claim 1 , further comprising less than 0.05 wt % phosphate based on the total weight of the stabilizer composition. 
     
     
         7 . The stabilizer composition of  claim 6 , further comprising less than 0.0001 wt % phosphate based on the total weight of the stabilizer composition. 
     
     
         8 . The stabilizer composition of  claim 7 , wherein the stabilizer composition is free of phosphate. 
     
     
         9 . The stabilizer composition of  claim 1 , further comprising less than 0.05 wt % silicate based on the total weight of the stabilizer composition. 
     
     
         10 . The stabilizer composition of  claim 9 , further comprising less than 0.0001 wt % silicate based on the total weight of the stabilizer composition. 
     
     
         11 . The stabilizer composition of  claim 10 , wherein the stabilizer composition is free of silicate. 
     
     
         12 . The stabilizer composition of  claim 1 , comprising at least one aminocarboxylate and at least one polyamino acid. 
     
     
         13 . The stabilizer composition of  claim 1 , comprising at least two aminocarboxylates. 
     
     
         14 . The stabilizer composition of  claim 1 , comprising at least one aminocarboxylate, at least one polyamino acid, and at least one hydroxy acid. 
     
     
         15 . A method of stabilizing the bleaching of pulp at an alkaline pH comprising:
 adding from about 1.0 lb. to about 5.0 lbs. per dry ton of pulp of the stabilizer composition of to a pulp composition prior to any bleaching of said pulp composition; and   adding at least one peroxide to the pulp composition at an alkaline pH after addition of the stabilizer composition to form a bleached pulp, wherein said stabilizer composition comprises:   a) about 50 wt % to about 80 wt % of at least one aminocarboxylate;   b) about 5.0 wt % to about 20 wt % of at least one hydroxy acid;   c) about 1.0 wt % to about 10 wt % of at least one polyamino acid, at least one iminodisuccinate, or both,   wherein a), b), and c) are different from each other, and wherein each wt % is based on the total weight of the stabilizer composition.   
     
     
         16 . The method of  claim 15 , further comprising adjusting the pH of the pulp composition to a pH of from about 9 to about 12. 
     
     
         17 . The method of  claim 15 , further comprising heating the pulp composition to a temperature of from about 120° F. to about 160° F. 
     
     
         18 . The method of  claim 15 , further comprising adding at least one sulfur-containing compound to the pulp composition prior to the addition of the at least one peroxide. 
     
     
         19 . The method of  claim 18 , wherein the at least one sulfur-containing compound comprises at least one sulfite. 
     
     
         20 . The method of  claim 15 , further comprising forming the bleached pulp into a paper product having a brightness greater that that achieved by using a single stabilizing agent. 
     
     
         21 . The stabilizer composition of  claim 1 , wherein c) is at least one iminodisuccinate. 
     
     
         22 . The stabilizer composition of  claim 1 , wherein c) is at least one iminodisuccinate and at least one polyamino acid. 
     
     
         22 . The method of  claim 15 , wherein c) is at least one iminodisuccinate. 
     
     
         23 . The method of  claim 15 , wherein c) is at least one iminodisuccinate and at least one polyamino acid.