Cotton dyeing with sulfur black dye

Defectively dyed apparel is made into one or more batches to dye with sulfur black dyes.

Process of Cotton dyeing:

• L: R = 1: 10 (for 150 kg)
• 60 kg salt @ 40% of liquor
• Raise temp. to 60º C by steam supply.
• After 15 min add sulfur black @ 12% + Sodium Hydrosulfide @ 14% of liquor
• Raise temp. to 80º C and continue processing for 120 mins.
• Raise temp. to 90º C add Sodium Carbonate @ 5%. Continue processing for 60 mins.
• Reduce dyeing temp. 70º C and drop the dye liquor

• To remember unfixed dye, a hot wash at 50º C with 0.5% detergent for 15 minutes with 1500 liter water. Continue washing for 5 mins without temperature 
• Sulfur black-dyed garments if stored, may form sulfuric acid which will reduce garment strength. To avoid this, 3% unidol SF paste may be used.
• Dyeing with sulfur dye is very dirty work for m/c, the floor, operators & environment should be cleaned well for further processing. 

Cotton sweater dyeing with pigment:

1. Pretreatment (Bleaching, scouring)

 2. Singeing:

Cellulose (Denimex 992 L)) Enzyme @ 1 g/L

Acetic acid = P^H 4.5

Temp. = 55⁰C

Time= 30 min

3. Pigment dyeing:

Cationic agent (Prifix K) 1g/L

Soda ash = P^H 8.5

Pigment Red H3BD @ 0.5% anionic pigment forms a bond with cationic cotton

Binder @ 1g/L forms a preliminary net structure with pigment and fabric

4. Washing:

Softener 0.5 g/L

Acetic acid = 5.5 P^H

• During drying, the final fixation of the binder takes place.

Md Mahedi Hasan

Mahedi Hasan is a Textile Engineer, as well as a Top Rated content writer at Upwork, a Level 02 Seller at Fiverr, Level 02 Publisher at Ezoic. A passionate textile and fashion content writer, fashion SEO expert, and fashion web designer. Having a B.Sc. in Textile Engineering Degree from Textile Engineering College, Noakhali (TECN). The department is Apparel Engineering. Highly Experienced fashion writer for the last 3+ years. Have extensive 7 years of experience in the wholesale clothing business.