Hygienic Property of Microfiber Synthetic Leather Base Modified via a “Two-Step Method”

A “two-step method” was adopted to improve the hygienic property of polyamide microfiber synthetic leather base. Firstly, the amino-terminal hyperbranched polyamides (NH 2 -HBP) synthesized by N, N'-methylene bisacrylamide (MBA) and diethylene triamine (DETA) was cross-linked to microfiber synthetic leather base pretreated with formic acid, in which glutaraldehyde was the crosslinking agent. Secondly, Gelatin hydrolysate was cross-linked to the preliminary modified microfiber synthetic leather base by using glutaraldehyde as the crosslinking agent. The modified microfiber synthetic leather base was then obtained. Hygienic performances, mechanical properties, and the micro morphology were taken as indexes to optimize the dosages of glutaraldehyde and NH 2 -HBP. The results show that when the glutaraldehyde dosage was 1.1 times that of the primary amino groups (the primary amino group dosage was about 0.201 mmol/g), the modification effect improved greatly. In this condition, the water vapor permeability, hygroscopicity, tensile strength, and tear strength of the base were 0.7691 g/10 cm 2 ·24 h, 3.357 mL/g·24 h, 18.79 N/mm 2 , and 103.18 N/mm, respectively. These values were 86.7%, 48.8%, 19.8%, and 2.69% higher than those of unmodified base, respectively. When NH 2 -HBP dosage was three times that of the primary amino groups, the modification effect also improved. In this case, the water vapor permeability, hygroscopicity, tensile strength, and tear strength of the base were 0.5761 g/10 cm 2 ·24 h, 3.274 mL/g·24 h, 18.79 N/mm 2 , and 103.4825 N/mm, respectively. These values were 113%, 42.3%, 3.5%, and 2.98% higher than those of the unmodified base, respectively. Meanwhile, the SEM image of the modified base showed that fiber dispersion was greatly increased in this condition.