A Maleinuric Acid / Acrylic Acid Copolymer with Functions of Softening Wet-Blue and Scavenging Free Formaldehyde in Leather

A low molecular weight copolymer suitable for retanning wet-blue in leather industry has been synthesized by copolymerizing maleinuric acid with acrylic acid. Its performances for improving physical properties of crust leather, fixing the free chromium salt existed in wet-blue and scavenging the free formaldehyde introduced by other chemicals were investigated by applying it on goatskin wet-blue. The results show that the strengths and extensions, especially the softness of the crust leather can be significantly improved by the copolymer. The chromium released from wet-blue during retanning and free formaldehyde in leather can be reduced by 84.9% and 70.4% respectively with an offer of 3% the copolymer. Soft leather with very low levels of chromium release and free formaldehyde could be obtained by retanning with this copolymer. Therefore, this copolymer has the good potential for industrial application in ecological leather.