Abstract

In order to reduce the apparent density of the finished leather and the amount of fatliquor used during leathermaking, a polymer auxiliary with silicone has been synthesised by radical copolymerisation of acrylic acid, methacrylic acid and polyvinyl silicone oil etc. The polymers were applied in the re-tanning process of sheepskin. Comparing the viscosity and applied properties of the polymer auxiliary with silicone, the mol ratio of acrylic acid, methacrylic acid used was confirmed to be 0.5:0.2, the consumption of polyvinyl silicone oil, ammonium persulfate, the reactive temperature and time were 5%, 1.5%, 80-85°C, 120-180 minutes, respectively. Infrared spectroscopy shows that the structure of the polymer auxiliary contains -Si-O- bond. The thickening increase and softness of the treated leather are 23.1%, 6.0 and the consumption of fatliquoring agent after re-tanning can be reduced to 4~8% when the optimum consumption of the polymer auxiliary is 8~10%, the retreated leather is fine grained, soft, hydrophobic and the apparent density is 0.457g/cm3.