Inside the supply chain: Bromo Indigo granules for modern denim and cotton

If you’re hunting for an indigo blue granular company that actually ships consistent vats and not just promises, here’s one worth knowing: HEBEI FUXIN INTERNATIONAL TRADE CO., LTD. I’ve followed vat-dye supply for years and, to be honest, granule stability still separates winners from the rest.

Product snapshot: Bromo Indigo (Vat Blue 5)

Product Name: Bromo Indigo; Vat Bromo-Indigo; C.I. Vat Blue 5 — CAS 2475-31-2 — Molecular formula: C16H6Br4N2O2. Origin: HEBEI FUXIN INTERNATIONAL TRADE CO., LTD., A-1205, MCC World Grand Plaza, 66 Xiangtai Road, Shijiazhuang 050023, China. Major usage: dyeing cotton fabrics (denim, yarn-dye shirtings, workwear).

How mills actually run it

Short version: it’s a vat dye. You reduce, apply, then oxidize.

• Materials: Bromo Indigo granules, NaOH, sodium dithionite (hydros), wetting/dispersing agent.
• Reduction: 50–60°C, pH 12–13, dissolve/convert to leuco state for bath or padding.
• Application: Pad-dye or exhaust; aim even pick-up; watch redox potential (≈ −650 to −700 mV).
• Oxidation: Air or H2O2; then soap at 90–95°C to remove unfixed dye.
• Testing: ISO 105-C06 wash; ISO 105-B02 light; ISO 105-X12 rub; AATCC 61/116 as needed.
• Service life: On cotton denim, wash fastness Grade 4–5; light fastness 6–7 (xenon) is typical.

Industries: denim weaving/rope dyeing, garment dye, heavy-duty workwear, yarn-dyed home textiles. Many customers say shade is slightly redder than standard indigo—useful for premium vintage looks.

Why choose indigo blue granular company supply

• Granule flow and low dusting (operators appreciate this—less mess, steadier dosing).
• Consistent redox behavior; surprisingly fewer “tiger stripes” in pad lines when tuned.
• Customization: shade tuning, dispersant package, moisture spec, private-label packing.

Field notes and small case study

One mid-size South Asian denim mill trialed these granules on a 6-box rope line. After tweaking hydros and caustic by ~1.5%, they reported smoother levelling and Grade 4–5 wash fastness (ISO 105-C06). Shade was a hair red—fashion team loved it; QA flagged fewer back-staining issues after a hotter soap. Not life-changing, but real.

Specs, testing, and data points

• Typical fastness (on cotton): Wash 4–5 (ISO 105-C06); Dry rub 4, Wet rub 3–4 (ISO 105-X12); Light 6–7 (ISO 105-B02). Actual results depend on recipe and fixation.
• Safety/compliance: CAS 2475-31-2; align programs with REACH and ZDHC MRSL screening before mass production.
• Documentation: COA per lot; SDS on request; shade card and lab-dip support available.

Author’s tip: In pad lines, watch redox online; don’t chase shade with extra hydros—balance pick-up and pH first. And yes, keep granules dry; they’re hygroscopic enough to drift dosing over time.

References

1. ISO 105-C06: Textiles — Tests for colour fastness — Colour fastness to domestic and commercial laundering. https://www.iso.org/standard/63836.html
2. ISO 105-B02: Textiles — Tests for colour fastness — Colour fastness to artificial light: Xenon arc fading lamp test. https://www.iso.org/standard/72226.html
3. ISO 105-X12: Textiles — Tests for colour fastness — Colour fastness to rubbing. https://www.iso.org/standard/67492.html
4. AATCC 61 / 116 Test Methods. https://www.aatcc.org/standards/
5. ZDHC MRSL Guidelines. https://www.roadmaptozero.com/