Vegetable Tannins as Chrome-Free Leather Tanning

Table 1

Recipe for tanning of sheep pickle pelt using Cassia singueana and Mimosa extract.

Type of process	Chemicals	Amount (%)	Duration (min)	Remark
Pickling	Water	50		Check °Be 6–8
	Common salt	7	15
	Formic acid (1 : 10)	0.3	30	Check pH 3.5–4.0
	Sulphuric acid (1 : 20)	0.2	60	Check pH 3.5–4.0
	Drain 50% of the float
Tanning	Mimosa (standard)	25	120	Check penetration
	Cassia singueana at 37°C	25	120	Check penetration
	Formic acid (1 : 10)	1	60	Check pH 3.8–4.2
Washing	Water at 35°C	100	30	Drain
	Water at 35°C	100	15	Drain
Fatliqouring	Fasfol Sc	2	60	Check exhaustion
	Lipsol J-622	1.5	60	Check exhaustion
Finishing	Leather was hanging on overhead track for overnight