The development of organic chromium-free tanning agents is currently a major research focus in leather tanning. However, these agents decrease the electrical potential of the tanned leather, which hampers the absorption of subsequent anionic dyes and fatliquoring agents. Consequently, issues such as lower color fastness, poor dyeing effects and environmental pollution arise. To address these challenges, this study proposes the utilization of anionic polyurethane (CWPU) as a dye fixing agent to enhance its performance and application in the leather preparation process. CWPU was successfully synthesized using polycarbonate diol (PCDL), isophorone diisocyanate (IPDI), polypropylene glycol (PPG), and N-methyldiethanolamine (MDEA) as raw materials, and the optimal synthesis conditions were optimized. The experimental results showed that the synthesized CWPU color fixing agent exhibited excellent emulsion properties and comprehensive performance when the PCDL: PPG ratio was 1:1 and the MDEA addition amount was 6 wt%. When applied to leather color fixation, the leather not only achieved improved dry and wet rubbing fastness levels of 4–5 but also demonstrated significant improvements in solvent wash resistance and perspiration fastness. Furthermore, the leather treated with CWPU color fixing agent exhibited deeper color and improved physical and mechanical properties and tactile quality. Therefore, this study provides an effective choice of color fixing agent for environmentally friendly chromium-free tanning systems and has broad prospects for the application of acid dyes.

中文翻译：

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阳离子水性聚氨酯的制备及其在皮革染色中的应用


有机无铬鞣剂的开发是目前皮革鞣制的主要研究热点。然而，这些试剂降低了鞣制皮革的电势，这阻碍了后续阴离子染料和加脂剂的吸收。从而出现色牢度较低、染色效果差、环境污染等问题。为了应对这些挑战，本研究提出利用阴离子聚氨酯（CWPU）作为固色剂来增强其性能和在皮革制备过程中的应用。以聚碳酸酯二醇（PCDL）、异佛尔酮二异氰酸酯（IPDI）、聚丙二醇（PPG）、N-甲基二乙醇胺（MDEA）为原料成功合成了CWPU，并优化了最佳合成条件。实验结果表明，当PCDL:PPG比例为1:1、MDEA添加量为6wt%时，合成的CWPU固色剂表现出优异的乳液性能和综合性能。当应用于皮革固色时，皮革不仅提高了4-5级的干湿摩擦牢度水平，而且在耐溶剂洗和汗渍牢度方面也表现出显着改善。此外，经CWPU固色剂处理的皮革颜色更深，物理机械性能和触感质量得到改善。因此，本研究为环保型无铬鞣制体系提供了有效的固色剂选择，对酸性染料的应用具有广阔的前景。