Cutting and double-face leather integrated dyeing process for tan sheep skin

A cutting and double-face leather integrated dyeing process for Tan sheep skin, wherein the process comprises the following steps:

• S1:
• Cutting wherein the cutting is performed by selecting the third-grade Tan sheep skin to do the cutting treatment, the cutting length being about 2-3 cm;
• S2:
• Washing with water wherein the washing with water is performed by washing the cut Tan sheep skin with water;
• S3:
• Retanning wherein the retanning is performed by retanning the Tan sheep skin washed with water;
• S4:
• Primary dyeing wherein the primary dyeing is performed by putting the retanned Tan sheep skin into a paddle to do the primary dyeing treatment, and a temperature for the primary dyeing treatment being 60-70° C., lasting for 2-3 hours, a pH value of the primary dye liquor being 2.5-3.5, a liquid ratio being 1:20;
• said primary dye liquor including 0.5 ml/L of fur colour leveling agent, 5 g/L of anhydrous sodium sulfate, 0.5 ml/L of brightening agent and 1.5-5 g/L of acid dye, the fur colour leveling agent being a composition of Propanetriol and fatty amine polyoxyethylene ether, the brightening agent being a composition of 25% Dimethylpolysiloxane, 5% Polyoxyethylene isodecyl ether and 70% water;
• S5:
• Primary colour fixing wherein the primary colour fixing is performed by that after the primary dyeing treatment, the primary colour fixing treatment is done by putting 0.5-1.0 ml/L of formic acid into the paddle every 30 minutes for two to three times, and after the primary colour fixing, taking the skin out and changing the water;
• S6:
• Secondary dyeing wherein the secondary dyeing is performed by that after the primary colour fixing, putting the Tan sheep skin into the paddle to do the secondary dyeing treatment, and a temperature for the secondary dyeing treatment being 25-30° C., lasting for 60-70 minutes, a pH value of the secondary dye liquor being 2.0-3.0, a liquid ratio being 1:20;
• said secondary dye liquor including 0.5 g/L of leather board leveling agent, 0.5 ml/L of ammonia water and 2-4 g/L of leather board dye;
• S7:
• Fatliquoring wherein the fatliquoring is performed by that after the secondary dyeing treatment, the fatliquoring treatment is done by putting a fatliquoring agent into the paddle and rotating it for 90-95 minutes, said fatliquoring agent including 3 ml/L of a first fatliquoring agent and 4 ml/L of a second fatliquoring agent, the first fatliquoring agent being a composition of C18H38—O—SO3Na and Fatty Alcohol Polyoxyethylene Ether of the formula C12H25O(CH2CH2O)3H with 3 alcohol ethoxylates, the second fatliquoring agent being a composition of 49% water, 18% highly raffinated mineral oil, 8% Dodecyltrimethylammonium chloride, 5% Sodium bicarbonate, 10% Paraffin oil and 10% Vegetable oil;
• S8:
• Secondary colour fixing wherein the secondary colour fixing is performed by that after the fatliquoring, the secondary colour fixing treatment is done by putting 1.5-2.0 ml/L of formic acid into the paddle, and rotating it for 1 hour, then putting 1.5-2.0 ml/L of formic acid every 30 minutes for three to four times, and after the secondary colour fixing, taking the skin out;
• S9:
• Bleaching wherein the bleaching is performed by that after the secondary colour fixing treatment, the bleaching treatment is done by putting 0.5-1.5 ml/L of fur degreasing agent into the paddle and bleaching for 15-20 minutes, the Fur Degreasing Agent being a composition of Fatty Alcohol Polyoxyethylene Ether of the formula RO(CH2CH2O)nH with 9 alcohol ethoxylates wherein R═C12-18 and n=15-16 and Sodium Alcohol Ether Sulphate;
• S10:
• Drying wherein the drying is performed by shaking the bleached Tan sheep skin dry, nailing the skin on a plate, air drying naturally and getting a finished product.