Formaldehyde-free, accelerated cure, aqueous composition for bonding glass fiber heat-resistant nonwovens

A method for curing formaldehyde-free polyacids comprising:

• (a) forming a formaldehyde-free curable aqueous composition comprising admixing:
• (1) a polycarboxylic acid comprising at least two carboxylic acid groups, anhydride groups, or salts thereof;
• (2) an active hydrogen containing compound containing at least two active hydrogen groups selected from the group consisting of hydroxyl, primary amino, secondary amino, and mixtures thereof;
• (3) a fluoroborate accelerator;
• and
• (4) a phosphorus containing accelerator selected from the group consisting of hypophosphorus acid, sodium hypophosphite, sodium phosphite, potassium phosphite, disodium pyrophosphate, tetrasodium pyrophosphate, sodium tripolyphosphate, potassium tripolyphosphate, potassium phosphate, and mixtures thereof:
• wherein the ratio of the number of equivalents of said carboxylic acid groups, anhydride groups, or salts thereof to the number of equivalents of said active hydrogen groups is from 1/0.01 to about 1/3, and the said carboxylic acid groups, anhydride groups, or salts thereof are neutralized to an extent of less than 35 mole % with a fixed base;
• and
• (b) heating said formaldehyde-free curable aqueous composition at a temperature of from 150.degree. C. to 400.degree. C.

A method for bonding glass fiber heat-resistant nonwovens with a formaldehyde-free binder comprising:

• (a) forming a formaldehyde-free curable aqueous composition comprising admixing:
• (1) a polycarboxylic acid comprising at least two carboxylic acid groups, anhydride groups, or salts thereof;
• (2) an active hydrogen containing compound containing at least two active hydrogen groups selected from the group consisting of hydroxyl, primary amino, secondary amino, and mixtures thereof;
• (3) a fluoroborate accelerator;
• and
• (4) a phosphorus containing accelerator selected from the group consisting of hypophosphorus acid, sodium hypophosphite, sodium phosphite, potassium phosphite, disodium pyrophosphate, tetrasodium pyrophosphate, sodium tripolyphosphate, potassium tripolyphosphate, potassium phosphate, and mixtures thereof:
• wherein the ratio of the number of equivalents of said carboxylic acid groups, anhydride groups, or salts thereof to the number of equivalents of said active hydrogen groups is from 1/0.01 to about 1/3, and wherein said carboxylic acid groups, anhydride groups, or salts thereof are neutralized to an extent of less than 35 mole % with a fixed base;
• (b) contacting said glass fiber heat-resistant nonwoven with said formaldehyde-free curable aqueous composition;
• and
• (c) heating said formaldehyde-free curable aqueous composition at a temperature of from 150.degree. C. to 400.degree. C.