亚硫酸氢钠封端多羧基聚氨酯助鞣性能的研究

The Study of Multi-carboxyl Polyurethane Blocked by Sodium Bisulfate in Tanning Process

异佛尔酮二异氰酸酯与酒石酸制备的预聚体用亚硫酸氢钠作为封端剂进行封闭后,得到一种小分子多羧基聚氨酯产物,研究了其作为铬鞣助剂对裸皮的耐湿热稳定性和浸酸膨胀性、铬鞣革坯收缩温度、鞣制废液中Cr2O3含量及铬鞣剂吸收率的影响。结果表明:该铬鞣助剂能够与皮胶原蛋白发生结合,可引入大量羧基,同时使裸皮胶原纤维得到初步固定,提高耐湿热稳定性,有效抑制裸皮在浸酸过程中的膨胀作用,依据其用量不同可以进行少盐或无盐浸酸;该助剂使用后,能使铬鞣革坯的收缩温度提高到113℃以上,铬鞣剂的吸收率提高到85%以上,鞣制废液中Cr2O3含量降低到2 215 mg/kg以下,而并且其用量的增加可以加强这种影响作用。

Multi-carboxyl polyurethane which was synthesised by isophorone diisocyanate and tartaric acid and bolocked by sodium hydrogensulfite. It was used as a chrome exhaustion in chrome tanning process. The relationship between assistant and hydrothermal stability of bated skin, plumping power in pickling process, shrinkage temperature of blues,Cr2O3 content of tanning wastewater and absorptivity of tanning agent were studied. The results show that this assistant can react with collagen, and it can bring a lot of carboxyl groups on collagen fiber surface. At the same time, the fiber is initial fixed, the skin is controlled plumping in pickling process. So it can achieve salt-less or salt-free pickling by changing the dosage of assistant. Otherwise, the using of multi-carboxyl polyurethane can improve shrinkage temperature above 113 ℃,increase absorptivity of tanning agent above 85% and decrease Cr2O3 content below 2 215 mg/kg. With the rising of the dosage, it can enhance these effects.