SUSTAINABLE TECHNOLOGIES FOR PROCESSING OF HIDES, LEATHER, WOOL, AND ASSOCIATED BYPRODUCTS
Location: Eastern Regional Research Center
Title: Treatment of low-quality hides with fillers produced from sustainable resources. Effect on properties of leather.
Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 25, 2009
Publication Date: October 1, 2009
Citation: Taylor, M.M., Lee, J., Bumanlag, L.P., Hernandez Balada, E., Cooke, P.H., Brown, E.M. 2009. Treatment of low-quality hides with fillers produced from sustainable resources: Effect on properties of leather. Journal of American Leather Chemists Association. 104(10):324-334.
Interpretive Summary: Poor quality loose grain hides are a continuing problem to the tanning industry. How hides are processed when they are converted to leather may be a contributing factor to this problem, however, a more perplexing dilemma is hides with loose grain that sometime appear in the early spring; these latter hides have been commonly referred to as having “spring break”. When these hides are converted to leather, the tanner can experience a lower economic return because of this defect. Tanners have tried treating the hides with many products (among which are polymers, resins, and protein fillers) to help correct this problem; the addition of protein products have shown moderate success. In recent years, we have produced and successfully applied filler-type products, for leather processing, by enzymatically treating waste proteins (such as gelatin from leather industry and casein and whey from the dairy industry). These treatments have resulted in leather products with improved properties. When these products were applied to spring break hides it was found that the finished leather had mechanical properties (e.g., strength) which were not significantly different than untreated control samples, but, more importantly, the subjective properties (e.g., grain appearance) were much improved, particularly in those areas of the hide that were affected the most by loose grain. Applying these treatments to spring break hides makes economic sense. Firstly, leathers are produced that have increased cutting area, and, secondly, these renewable resources have the potential to replace the more conventional petroleum feedstuffs that are increasingly becoming scarce as well as expensive.
Prior research from this laboratory reported on the use of gelatin, alone or in combination with dairy byproducts (casein or whey), as a filler for leather. It was found that all these treatments had fully penetrated the blue stock, were not removed during washing, and had no significant effect on mechanical properties when compared to untreated controls, but did show improvements in the subjective evaluations over the controls with respect to handle, break, dye uptake, and fullness. In this present study we applied these treatments to hides that had grain properties that were characterized as being loose, more commonly known as having “Spring Break”, to see if a reduction in these undesirable properties could be realized. The treatments were applied to the butt, belly and neck areas of the hide, and these samples were subsequently retanned, colored and fatliquored (RCF). There were no significant differences between the untreated controls and treated samples with respect to mechanical properties. Importantly, however, it was determined from subjective evaluations, that those commonly inferior areas, such as belly and neck, showed improved cutting area when treated. At the same time, Scanning Electron Microscopy (SEM) was used to compare the blue stock of both poor quality hides and hides evaluated to be of better quality before and after RCF; distinct differences in fiber structure were observed, most dramatically in the belly area. Applying these treatments to low quality hides makes economic sense. Firstly, leathers are produced that present more quality cutting area, and, secondly, these renewable resources have the potential to replace petroleum feedstuffs that are increasingly becoming scarce as well as expensive.