Abstract

A new compound, N-thioureidopyromellitamic acid, has been synthesized from pyromellitic dianhydride and thiosemicarbazide, and a condensate has been prepared from this compound and glyoxal. We have investigated pretreatment with the condensate prior to aluminium tanning. The results show that the pretreated pelt has a lower shrinkage temperature than conventionally processed pelt but subsequent aluminium tanning results in a significant increase in shrinkage temperature. A white leather with good thermal and dyebath stability, as well as higher strength, has been obtained using the pretreatment with a citrate-masked aluminium tannage.