Oral · Pages 112–120
Abstract
Research summary supplied by the authors
The use of vegetable tanning agents could be an alternative to synthetic tanning agents with regard to sustainability and reduction of fossil based materials in leather production. In recent years, a new group of secondary plant compounds, the iridoids or secoiridoids, has been investigated for its use as tanning agents. Secoiridoids are found in relevant concentrations in leaves from olive trees or privet shrubs. Extracts from these two secoridoid containing plants are investigated for their tanning characteristics. Extracts from privet (Ligustrum vulgare) leaves show the same high crosslinking activity as extracts of olive leaves. In addition to Oleuropein found in olive leaves, the privet extracts contain a high proportion of the secoiridoid Ligustaloside A. The tanning activity of olive and privet leaf extracts is determined by crosslinking of the model compound hide powder. A comparison to aldehyde crosslinking was investigated with regard to concentration and temperature of denaturation. After investigating the crosslinking activity by the hide powder method, a technology for the production of leather was developed that uses Ligustrum tanning exclusively for pre-tanning. Properties of the resulting leather are discussed, including mechanical and shrinkage characteristics during climate change tests.