Chrome-free tanning is an emerging trend for the green sustainable development of the leather manufacturing industry. However, conventional anionic wet finishing materials for chrome-tanned leather are not suitable for chrome-free tanning systems due to the imbalance of surface charge between the wet finishing materials and chrome-free tanned leather. In this paper, we have developed a novel and facile approach to synthesizing an amphoteric polymer named PAMLD as a retanning/fatliquoring agent for chrome-free tanned leather. The PAMLD polymer with a suitable particle size (d = 325 nm) and appropriate isoelectric point (pI = 4.6) was prepared by one-step copolymerization in an aqueous solution using acrylic acid (AA), methacrylic acid (MAA), ethyl methacrylate trimethylammonium chloride (DMC), and dodecyl 2-methyl acrylate (LMA) as monomers. The obtained amphoteric polymer was further applied in the wet finishing processing of three types of chrome-free tanned leather. Comprehensive characterizations of leathers treated with PAMLD indicated the retanning and fatliquoring effect of PAMLD on collagen fibers. Moreover, leathers treated with PAMLD exhibited better dyeing properties compared with those treated with the commercial amphoteric wet finishing material (FRA), as evidenced by their superior K/S values and color fastness to rubbing and washing. This research not only provides a feasible approach for preparing multifunctional amphoteric polymers but also offers novel matching wet finishing materials and strategies for variable chrome-free tanned leather production.

中文翻译：

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生态无铬鞣革生产助染两性丙烯酸复鞣/加脂剂开发的见解

无铬鞣制是皮革制造业绿色可持续发展的新兴趋势。然而，传统的铬鞣皮革阴离子湿整理材料由于与无铬鞣革表面电荷不平衡，不适合无铬鞣制体系。在本文中，我们开发了一种新颖且简便的方法来合成名为 PAMLD 的两性聚合物，作为无铬鞣革的复鞣/加脂剂。采用丙烯酸(AA)、甲基丙烯酸(MAA)、甲基丙烯酸乙酯三甲基铵在水溶液中一步共聚制备出具有合适粒径(d = 325 nm)和合适等电点(pI = 4.6)的PAMLD聚合物氯化物（DMC）和丙烯酸2-甲基十二烷基酯（LMA）作为单体。所得两性聚合物进一步应用于三种无铬鞣革的湿整理加工中。经过 PAMLD 处理的皮革的综合表征表明了 PAMLD 对胶原纤维的复鞣和加脂作用。此外，与用商用两性湿整理材料（FRA）处理的皮革相比，用 PAMLD 处理的皮革表现出更好的染色性能，其优异的 K/S 值以及耐摩擦和水洗色牢度证明了这一点。该研究不仅为制备多功能两性聚合物提供了一种可行的方法，而且为可变无铬鞣革生产提供了新型配套湿整理材料和策略。