Effects of alpha-tocopherol addition to polymeric coatings on the UV and heat resistance of a fibrous collagen material-chrome-free leather

摘要

The US is the world's 3rd largest hide producing country and currently produces approximately 35 million cattle hides annually. The majority of hides are tanned into leather, which is composed of collagen fibers interwoven into fibrous networks. Most leather products are constantly exposed to outdoor environments, therefore UV and heat resistance are very important qualities, particularly for nonchrome-tanned (chrome-free) leather. In recent years, we have focused on using environmentally friendly antioxidants that will improve the UV and heat resistance of chrome-free leather. Tocopherols are well-known antioxidants commonly used in the cosmetic and food industries. They are known as potent free radical scavengers and highly protective agents for collagen fibers against UV damage. We have investigated their potential to improve the UV and heat resistance of chrome-free leather. Experiments were conducted by adding 5-12% α-tocopherol to the polymeric topcoat on the grain of chrome-free leather. The treated samples were tested in a weatherometer, where they were exposed to artificial sunlight. Colorfastness and mechanical property tests showed that α-tocopherol significantly improved UV and heat resistance of leather. Dynamic mechanical tests showed that α-tocopherol reduced the hardening effects on leather caused by UV irradiation.