Sulfur Black Dyestuff Manufacture

Sulfur Black (also known as Sulfur Black BRN or Sulfur Black BN) is the most produced type of sulfur dye, accounting for over 75% of the world's total sulfur dye output. It is a high-molecular-weight compound containing sulfur. It is widely used for dyeing cotton, linen, viscose, and other cellulose fibers due to its low cost and good fastness properties.

Product Forms

Depending on the physical state and process, it mainly comes in three forms:

· Regular Powder/Flake: Appears as black flakes or granules. It is insoluble in water and must be dissolved with a reducing agent like sodium sulfide. Fabrics dyed with this type risk tendering (strength loss) over time and usually require anti-tendering treatment.

· Solubilized Powder: A black powder that is soluble in water. It is easy to use, offers good penetration, and typically does not require anti-tendering treatment after dyeing.

· Liquid: Supplied in liquid form. It is pre-reduced, contains fewer impurities, offers high stability, and produces less wastewater. Its color fastness is usually about half a grade higher than the powder form.

Main Applications

· Textile Dyeing: Primarily used for dyeing cotton, linen, vinylon/cotton blends, and viscose fibers. It can be applied through exhaust dyeing, jig dyeing, or pad dyeing.

· Other Uses: The solubilized (water-soluble) type is also used for leather dyeing and paper dyeing.

Basic Properties

· Appearance: Black powder, flakes, or granular solid.

· Solubility: Regular powder is insoluble in water and alcohol but dissolves in a sodium sulfide solution to form a black-green leuco compound. Solubilized types dissolve directly in water.

· Core Identification: The main type is C.I. Sulfur Black 1, with CAS No.: 1326-82-5.

Important Note: Tendering (Strength Loss)

Fabric dyed with Sulfur Black may, over time, produce sulfuric acid due to the oxidation of sulfur in the dye. This acid can cause the cellulose fibers to become brittle and lose strength-a phenomenon known as tendering.

Prevention methods include:

· Thorough Washing: To remove unfixed dye and residual sulfur.

· Anti-tendering Treatment: Treating the dyed fabric with agents like urea, sodium acetate, or trisodium phosphate.

· Using Non-tendering Types: Selecting specially processed Non-tendering Sulfur Black dyes, which are stabilized during manufacturing (e.g., with formaldehyde and monochloroacetic acid).

Hot Tags: sulfur black dyestuff manufacture, China sulfur black dyestuff manufacture manufacturers, suppliers, factory, sulphur dyes for printed carpets, sulphur dyes for printed garments, sulphur dyes for tie dyeing, sulphur dyes for treated yarns, sulphur dyes for unbleached fabrics, sulphur dyes for unmercerized yarns