ESTER CROSS-LINKING TO IMPROVE WET PERFORMANCE OF PAPER USING MULTIFUNCTIONAL CARBOXYLIC-ACIDS, BUTANETETRACARBOXYLIC AND CITRIC-ACID

Butanetetracarboxylic acid and citric acid are two multifunctional car boxylic acids that have potential for use in formaldehyde-free durable press finishing of fabrics. In this study these acids were investigat ed as cellulose crosslinking agents for modifying the wet performance of paper board The crosslink reaction involves the formation of two es ter linkages per acid molecule to the hydroxyl-rich surface of cellulo se to form a covalently linked structure that restricts the swelling a ction of water. All wet properties of ester crosslinked paperboard wer e significantly improved, as were dimensional stability and creep perf ormance, two important dry properties-stretch and tensile energy absor ption-were seriously decreased. For speciality products where water-so ak properties of stiffness, dimensional stability, and reduced creep a re important and dry toughness is not important, ester crosslinking ma y be a solution to material needs. Ester crosslinking eliminates the p roblems that are encountered with formalldehyde crosslinking. It also affords a pad-dry-cure process that is compatible with paper machine o peration and yet has the advantage of a delayed cure option.