Abstract

Among the novel collagen crosslinkers currently being studied, polyepoxides (e.g. based on aliphatic polyol glycidyl ether), have shown certain potential in organic tannage applications. The work reported here is a comparison of the tanning abilities of some commercial epoxides with commonly used organic tanning agents, i.e. glutaraldehyde, oxazolidine and THPS. Studies have been based on the progress of tannage followed via crosslink density determination of treated gelatine (i.e. used as a collagen model). The investigation has also been concerned with comparing the physical, chemical, biological and morphological characters of the resultant leather.

The results show that the order of tanning ability to be: THPS > oxazolidine > glutaraldehyde >> epoxide. Epoxide, when used alone, is a fairly weak crosslinker of collagen and has to be used in relatively large quantities (an offer of 20% of skin weight). The epoxide has a slow reaction rate at room temperature and the resulting leather has lower hydrothermal stability (82°C) with a lower reacted amine content and tensile strength. However, this epoxide treated leather has high apparent density, moisture content and anti-trypsin degradation ability. The differences in tannage mechanisms for these reagents are discussed, in order to interpret the limitations of this type of epoxide.