Abstract

Glutaraldehyde is superior to other tanning agents when leather of good perspiration resistance is required, the tannage being also stable to washing processes and to contact with alkaline solutions generally. The final pH of tanning should be between 7 and 8 for full utilisation but initial penetration should be at about pH 4, when the affinity is relatively low and the pH then generally raised.

Although there is no specific method of determining glutaraldehyde in leather several methods of limited application for assessing the degrees of interaction are discussed.

Glutaraldehyde can also be used either as a pretannage or retannage with chrome or as a combination tannage in the same bath. Its application as a retannage offers the advantage of selection at the chrome crust stage as and when perspiration resistance is required in the finished leather. Although the perspiration resistance is not quite so high as when glutaraldehyde is the only tannage, laboratory tests suggest that the degree of protection is adequate. As with all retannages there is some loss in physical strength and with a thin gloving leather there is only a small margin of safety. Trials on cape type chrome crust (06 mm thickness) have explored a fairly wide range of retannage conditions with the object of determining the extent to which strength is reduced and the minimum treatment required to give satisfactory perspiration resistance.

The results suggest that the loss of strength is related to the degree of retannage rather than to any one process variable. A level of treatment has been found where the perspiration resistance is satisfactory and the loss of strength small.