Sulphur Blue 5

Sulphur Blue 5 (also sold as Sulfur Blue 5) is a deep navy sulfur dye designed for cotton and other cellulosic fibers. It delivers reliable wash and rub fastness when applied via the standard reduction-oxidation sulfur dyeing process.

Sulphur Blue 5 (Sulphur Dark Blue 3R) color is Navy blue,and Insoluble in water. In the Sodium sulfide solution solubility is good, for green light blue; In concentrated sulfuric acid for blue solution, dilution of dark after precipitation

Relative name

Sulphur Dark Blue 3R,Sulphur Fast Blue;Sulphur Navy Blue 3R;Sulphur Navy Blue B;

• Typical Form - Powder (standard) / Liquid dispersion (on request)
• Primary Fibers - Cotton, viscose; not recommended for nylon/wool
• Application - Exhaust / Pad-dying after reduction
• Fastness - Wash: High (when processed correctly). Light: Moderate

Sulphur Blue 5 is formulated to deliver consistent, economical navy shades for large-scale textile production. Unlike some azo or direct dyes, sulfur dyes are applied using a reduction stage (solubilization) followed by oxidation to regenerate the insoluble pigment within the fiber. This product is available both as a free-flowing powder and as a pre-dispersed liquid for easier handling in modern dye houses.

Key advantages

• Excellent substantive uptake on cotton and viscose — suitable for denim and workwear.
• High wash and rub fastness when standard sulfur dye procedures are followed.
• Available in multiple formats to suit manual or automated dosing systems.
• Cost-effective color source for high-volume & industrial processes.

General process outline (industrial reference):

• Prepare goods and ensure good wetting (pH and temperature per mill practice).
• Reduce the dye in alkaline sodium sulfide or proprietary reducing agent until soluble.
• Exhaust the reduced dye onto cellulosic fiber under agitation.
• Oxidize thoroughly (air/oxidizing agent) to develop the final shade; rinse and neutralize.

Note: the above is a workflow outline for guidance only. Perform lab trials to define exact dosages and parameters for your equipment and substrate.

Compatibility & blending tips

Sulphur Blue 5 blends well with other sulfur blacks/blues to adjust depth and undertone. Avoid mixing with dyes incompatible with sulfur chemistry (acid dyes, some vat dyes) unless specific compatibility tests have been completed.

Applications:

• ‍Mainly used for cotton, hemp, viscose fabric dyeing;
• can also be used to top and viscose fiber protoplasmic coloring. 
• Sometimes also used in leather and paper dyeing.‍

Technical Specifications

• ‍Product Name:Sulphur Blue 5
• C.I. No.: 53235
• CAS No.: 60569-85-9
• Shade: Navy blue‍

Package

25KG/DRUM, CARTON BOX, BAG

Troubleshooting & Scale-Up Tips

• Poor uptake: check reduction completeness and liquor-to-goods ratio; ensure thorough wetting.
• Uneven shades: confirm mechanical circulation and faster dye liquor replenishment; use dispersing aids if needed.
• Low wash fastness: review oxidation step; incomplete oxidation leaves soluble residues that wash away.

Note: The data contained here are based on our current knowledge and experience. It is the responsibility of user to test our products before the final application.