Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2008
Publication Date: 5/1/2009
Citation: Liu, C., Ramos, M., Latona, N.P., Latona, R.J. 2009. Leather Coated with Mixtures of Humectant and Antioxidants to Improve UV and Heat Resistance. Journal of American Leather Chemists Association. 104(5):161-168.
Interpretive Summary: There is an increasing demand from the automakers for the production of automotive leather. Ultraviolet (UV) and heat can have a detrimental effect on the durability of leather, especially for instrument panels and consoles, where temperatures reach well over 100°C. However, the current commercial UV and heat protective agents such as phenols and amine derivatives are not effective for either “aniline grade” or lightly finished automotive leather. These inadequacies are of paramount importance, especially for automotive applications, and need to be studied to determine why they occur and how they may be eliminated. We have been working on the development of a finishing process using environmentally friendly antioxidants that improve the UV- and heat resistance of automobile upholstery leather. We applied a mixture of glycerol and Vitamin E to the grain layer of chrome-free leather. Following exposure in a Fade-Ometer, the treated samples were evaluated by colorimetry and mechanical testing for the efficacy of UV- and heat resistance. Observation showed that leather treated with Vitamin E resulted in significant improvement in color fading resistance against UV radiation and heat. This research will expand the demand for domestic production of high quality, durable leather, thereby contributing to the viability of the domestic tanning industry.
Technical Abstract: Ultraviolet (UV) and heat resistance are very important qualities for leather products. We recently developed an environmentally friendly finishing process for improving the UV- and heat resistance of automobile upholstery leather. We previously reported and demonstrated some promising results from coating tocopherol, a natural antioxidant, onto the grain layer of leather. Tocopherol (Vitamin E) is a potent free radical scavenger and highly protective agent for collagen fibers against UV damage. This antioxidant has improved the UV- and heat resistance of the leather product. To help prevent over-drying, glycerol, a humectant, is added to tocopherol to not only maintain proper moisture content, but also to improve the UV and heat resistance of leather. The mixture of glycerol and tocopherol is applied as an emulsion with Sodium dodecyl sulfate (SDS), as an emulsifying agent, and coated the grain layer of the leather. Following exposure in a Fade-Ometer, the treated samples were evaluated by colorimetry and mechanical testing for the efficacy of UV- and heat resistance. Data showed that leather coated with glycerol/tocopherol exhibited significant improvement in color fading resistance against UV radiation and heat.