蓖麻油改性两性聚氨酯复鞣剂的制备及应用

Preparation and application of castor oil modified amphoteric polyurethane retanning agent

摘要:

两性聚氨酯与皮革胶原多肽结构相近，将其改性后作为复鞣剂加入至有机无铬鞣鞣制的皮革中可表现出良好的配伍性与反应性。然而，多数两性聚氨酯改性剂功能单一，且来自不可再生在石化资源，对环境不友好。基于此，本文首先以异氟尔酮二异氰酸酯（IPDI）和聚四氢呋喃二醚醇（PTMG）为原料，2, 2-二羟甲基丙酸（DMPA）为阴离子扩链剂，N-甲基二乙醇胺（MDEA）为阳离子扩链剂制备两性聚氨酯，之后使用环境友好且对胶原纤维具有柔顺作用的蓖麻油（CO）改性两性聚氨酯得到产物（COWPU）。实验结果表明COWPU被成功制备；且具有显著的两性特征（等电点为6.29）和良好的生物降解性（BOD5/COD=0.37）。之后将其用于有机无铬鞣鞣剂TWS鞣制的坯革，结果表明，经COWPU复鞣的皮革撕裂强度（36.32 N/mm）与抗张强度（9.99 Mpa）均优于市售两性丙烯酸复鞣剂复鞣后的皮革。此外，COWPU还对皮革有一定的柔顺作用，有望实现复鞣-加脂一体工艺。本实验可为有机无铬鞣制体系的皮革提供一种配套的两性复鞣剂。

Abstract:

Modified amphoteric polyurethane can be used in the retanning process of leather tanned by organic chrome-free tanning agent because of it’s structure is similar to leather collagen polypeptide and showed good compatibility and reactivity when added into leather. However, most amphoteric polyurethane modifiers have a single function and are derived from non-renewable petrochemical resources, which are not environmentally friendly. Hence, a amphoteric polyurethane was obtained by using isophorone diisocyanate (IPDI) and polytetrahydrofuran diether alcohol (PTMG) as raw materials, 2,2-dimethylolpropionic acid (DMPA) as anionic chain extender, N-methyldiethanolamine (MDEA) as cationic chain extender, then the product (COWPU) is obtained by using castor oil (CO), which is environmentally friendly and has a softening effect on collagen fibers, to modify amphoteric polyurethane. The results showed that COWPU was successfully prepared. It also has significant amphiprotic characteristics (isoelectric point 6.29) and good biodegradability (BOD5/COD=0.37). Then it was applied to retanning of leather tanned by chrome-free tanning agent TWS. The results showed that the tear strength (36.32 N/mm) and tensile strength (9.99 Mpa) of the leather retanned by COWPU were better than the leather retanned by the commercially available amphoteric acrylic retanning agent. In addition, COWPU has a certain softening effect on leather, which has the potential to realize an integrated process of fatliquoring and retanning. This research can provide a matching amphoteric retanning agent for leather tanned by organic chrome-free tanning system.