Engineering design of amphoteric acrylic polymer for rapid and reduced wet-finishing process of eco-leather production towards energy saving and carbon reduction

Abstract

Amphoteric polymers as leather retanning agents are considered to effectively address the charge imbalance between chrome-free tanned leather and common anionic wet finishing materials, and improve the quality of finished leather. However, the currently existed high chemical dosage and tedious wet finishing process associated with chrome-free tanning inevitably lead to high pollution emission and energy consumption. Herein, an amphoteric acrylic polymer (i.e., AARFA) with retanning and fatliquoring functions was prepared by free radical polymerization, which exhibited broad molecular weight (10−100 kDa) and appropriate particle size (∼200 nm). Molecular dynamics simulations and experiments showed that AARFA exhibited good dispersion in water and its aggregation behavior can be modulated by adjusting pH. We then applied AARFA in the rapid and reduced wet finishing process (RRWF) for two kinds of typical chrome-free tanned leather. Compared with conventional wet finishing (CWF) process (i.e., 10 % retanning agents and 10 % fatliquor), 12 % AARFA afforded leather dispersed collagen fibers, improved physical and sensory properties, and excellent dyeing performance. The RRWF process can effectively save work time by ∼31 %, reduce chemical consumption by ∼35 % and exhibit better wastewater degradability. Our developed RRWF process offer the promise for the chrome-free leather manufacturing towards low energy consumption and less carbon emissions.