Bromo Indigo (C.I. Vat Blue 5): real-world notes from the dye room floor

If you work with denim or heavy cottons, you eventually bump into indigo blue granular company sourcing questions. To be honest, the market can feel opaque. But Bromo Indigo—also called Vat Bromo-Indigo or C.I. Vat Blue 5—keeps showing up in mill conversations for one simple reason: it delivers the deep, stable blues brands want without endless rework. Origin-wise, HEBEI FUXIN INTERNATIONAL TRADE CO., LTD. out of Shijiazhuang, China, has become a name buyers ping me about more than I expected.

Industry pulse

Denim mills are chasing fewer shade corrections and better wash-down repeatability. Actually, with energy costs rising, mills tell me they prefer vat blues that reduce cleanly and build tone fast. The push toward tighter chemical stewardship—REACH, ZDHC, OEKO‑TEX—means traceability and documentation matter as much as price. A indigo blue granular company that can confirm lot-to-lot shade strength and provide quick COAs tends to win the week.

Technical snapshot

• Product names: Bromo Indigo; Vat Bromo-Indigo; C.I. Vat Blue 5
• Molecular formula: C16H6Br4N2O2; CAS: 2475-31-2; HS code: 3204151000
• Major use: dyeing cotton fabrics (denim, workwear, heavy twills)
• Origin: HEBEI FUXIN INTERNATIONAL TRADE CO., LTD., A‑1205, MCC World Grand Plaza, 66 Xiangtai Road, Shijiazhuang 050023, China

Typical process flow (vat dyeing)

1. Preparation: desize → scouring/bleaching (if needed) → thorough rinse
2. Vatting: reduce Vat Blue 5 using sodium dithionite + NaOH (≈ pH 11–12)
3. Dyeing: 40–60°C for yarn or rope dye; build shade in multiple dips if required
4. Oxidation: air or H2O2; then soap at 90–95°C to level and open shade
5. Testing: run ISO 105 series for wash/rub/light before scale-up

Product specifications (indicative)

Performance and testing

• ISO 105-C06 wash fastness on cotton: 4–5 grades (typical lab result) [1]
• ISO 105-B02 light fastness: 5–6 (depends on shade depth) [1]
• ISO 105-X12 rubbing: Dry 4–5; Wet 3–4 after proper soaping [1]
• Service life: garments ~2–5 years; workwear longer with mild detergents and low-temp cycles

Where it’s used

Denim mills (rope and slasher), garment dye houses for retro indigo looks, heavy cotton uniforms, and home textiles chasing heritage palettes. Many customers say Bromo Indigo handles repeated stone or enzyme washes without weird hue drift—surprisingly consistent when the reduction is kept clean.

Vendor comparison (buyer’s quick glance)

Customization and support

Ask for pilot packs with your preferred granule size (easier dust control), plus pre-reduced paste trials if your line allows it. A solid indigo blue granular company partner will tune wetting agents, advise on Na2S2O4 charge, and share lightfastness deltas at different depths.

Quick case notes

• Denim mill in Bursa: cut re-dye rate by ≈18% after standardizing oxidation and switching to consistent Vat Blue 5 lots.
• Workwear line in Vietnam: moved to granules to reduce dusting; operators reported cleaner vats and steadier build.

Compliance and references

Typical buyer requests: ISO 9001/14001 certificates, OEKO‑TEX Eco Passport statements, and REACH SVHC screening. Always verify with the supplier’s latest COA and SDS—it seems basic, but it saves headaches.

References:

1. ISO 105 series (Textiles—Tests for colour fastness), particularly C06 (domestic washing), B02 (light), X12 (rubbing).
2. Colour Index, Vat Blue 5 (C.I. 73000) entries and vat dye reduction principles.
3. OEKO‑TEX Eco Passport—Chemical input assessment framework for textile production.
4. European Chemicals Agency (ECHA) REACH guidance—Substances of Very High Concern (SVHC) screening.