Production of crust (shoe upper) leather from wet blue leather:
★ Acid wash:
Water ----------------------------------- 200%
Oxalic acid ---------------------------- 0 8%
Wetting agent (LD-600) -------------- 0.3%
(Run for 30 minutes)
then drain and rinse
★ Re-chroming:
Water ----------------------------------- 150%
Formic acid ---------------------------- 0.3%
(Run for 10 minutes)
Basic chromium sulphate ------------ 4%
Chrome syntan ------------------------ 4%
Sodium formate ----------------------- 1%
LDW/CB/GS -------------------------- 1%
(Run for 45-60 minutes)
GTW ----------------------------------- 1.5%
(run for 30 minutes)
Neosyn 9p ----------------------------- 2%
(run for 20 minutes)
Relugan RF---------------------------- 2%
(run for 20 minutes)
Sodium bi carbonate (1:20)
Drain
★ Neutralization:
Water ---------------------------------- 100%
BS -------------------------------------- 2%
Sodium formate ---------------------- 1%
(Run for 45 minutes)
Check pH 4.8 to 5.5 BCG
Drain
★ Re-tanning and dyeing:
water at 50°c ------------------------- 150%
RE ------------------------------------- 3%
(run for 20 min.)
Relugan DP-100 -------------------- 4%
(run for 30 min)
Neosyn N/OT ----------------------- 2%
(run for 10 min)
Acid black dye ---------------------- 3%
(run for 30 min)
Check penetration
Mimosa ------------------------------ 5%
Quebracho --------------------------- 5%
DLE ---------------------------------- 3%
OS ------------------------------------ 4%
(Run for 30 min)
Mimosa ------------------------------ 5%
Quebracho --------------------------- 5%
Syntan A W ------------------------- 3%
DLE ---------------------------------- 3%
OS ------------------------------------ 3%
(Run for 45 min)
Formic acid (1:3)------------------- 1.5%
(Run for 10 min + 30 min)
Drain and rinse
Wash with 200% water at 55 to 60°C for 5-10 min
★ Fat-liquoring
water at 50°C ---------------------- 150%
B-40 --------------------------------- 4%
C-2 ---------------------------------- 4%
Synthol-O -------------------------- 0.5%
Busan 30L ------------------------- 0.2%
(Run for 45-60 min)
Add Formic acid (1:3) ------------ 1%
(run for 10 min + 30 min)
Drain and wash well
★ Top dye and fat:
water at 55°C --------------------- 150%
Acetic acid ------------------------ 0.5%
(run for 10 min)
Basic black dye ------------------ 1%
(run for 30 min)
Acid black dye ------------------- 2%
(run for 30 min)
Formic acid ---------------------- 1%
(run for 30 min)
LDW ----------------------------- 0.5%
Synthol-O ----------------------- 0.5%
RF -------------------------------- 0.5%
Busan 30L ----------------------- 0.2%
Drain and rinse
Horse up overnight
★ Mechanical operation:
01. Setting - (flatten the the leather surface, smooth without any distortion of grain pattern)
02. Vacuum dry
03. Hang to dry
04. Tannel dry
05. Vibrating Staking
06. Toggle dry
07. Trimming
08. Kissplate
Then finishing.