ALKALI-METAL SALTS OF HYDROXY-ACIDS AS CATALYSTS IN DURABLE PRESS FINISHING WITH BUTANETETRACARBOXYLIC ACID

Alkali metal salts of hydroxy acids have been investigated as catalyst s for esterification cross-linking of cotton with 1,2,3,4-butanetetrac arboxylic acid to produce cotton fabrics with smooth drying properties . Of the sodium salts of several acids studied, the sodium citrates pr oduce fabrics with the best appearance properties. The sodium citrates serve both as donors of citric acid for cross-linking and of sodium i ons for catalysis of the esterification of cotton cellulose by the two polycarboxylic adds. Although the use of citric acid as an extender f or the more expensive butanetracarboxylic acid has been reported in no n-formaldehyde finishing of cotton fabrics for smooth drying propertie s, the catalyst used was sodium hypophosphite. Comparisons are made be tween fabrics finished with the phosphorus-containing system and the b utanetetracarboxylic acid/sodium citrate systems. Textile properties, fabric whiteness, effect of pad bath pH. and extent of esterification are discussed.