Abstract

Trials described in this paper showed that Perval-JO, the oxidised degradation product of valonia extract using 10% H,O,(w/w), had a synergistic effect with Cr(III). The combination tannages using 5—7% Perval JO and 1.0—I .5 Cr,03produced leather with shrinkage temperatures above 110 C. higher than that of the corresponding chrome tannage and a combination tannage using 15% valonia extract. The synergistic reaction of Perval-JO and Al(III) was not as effective as with Cr(III), but still produced leather with a shrinkage temperature above 100°C, when 7% Pen’al-JO was used. The tanning sequence in combination tannages using Penal-JO is not critical, perhaps due to its moderate astringency and rapid penetration rate. The vegetable tanned character of leathers tanned by combination tannages using Penal-JO was largely eliminated, so that the tannages are suitable for producing quality leathers similar to a chrome tannage.