Blacks
Six listed reactive blacksCOTFIX Reactive Blacks is Nuchem's six-product black-shade range. The published table lists Black WNN, Black 2R, Black 2N, Black WNN H/C, Super Black G and Super Black R, with individual fastness data and solubility of 100 g/L at 30°C. The first four entries are marked dischargeable; Super Black G and Super Black R are partially dischargeable. Tone and approval coverage require the exact product name.
Approval and conformance coverage varies by product and strength variant. Check product-specific evidence and request documents for your exact COTFIX grade; a series name is not a whole-range approval.
What reactive black dyes does the COTFIX range publish?
COTFIX Reactive Blacks is Nuchem's six-product black-shade range for cellulosic fibres. The published table lists Black WNN, Black 2R, Black 2N, Black WNN H/C, Super Black G and Super Black R. All six entries report solubility of 100 g/L at 30°C, dry rubbing of 4 and light fastness of 4. Wet rubbing is 3 to 4 for five grades and 4 for Black WNN. The first four entries are marked dischargeable, while Super Black G and Super Black R are partially dischargeable. Nuchem publishes the values product by product so a buyer can compare black grades before enquiring.
| Dye | Shade 2% | Solubility gpl 30°C | Rubbing Fastness (Dry) | Rubbing Fastness (Wet) | Light Fastness 1/1 S/D | Washing Fastness (Shade) | Washing Fastness (Cotton) | Dischargeability |
|---|---|---|---|---|---|---|---|---|
| Cotfix Black WNN | 100 | 4 | 4 | 4 | 4 | 3-4 | D | |
| Cotfix Black 2R | 100 | 4 | 3-4 | 4 | 4 | 3-4 | D | |
| Cotfix Black 2N | 100 | 4 | 3-4 | 4 | 4 | 3-4 | D | |
| Cotfix Black WNN H/C | 100 | 4 | 3-4 | 4 | 4 | 3-4 | D | |
| Cotfix Super Black G | 100 | 4 | 3-4 | 4 | 4 | 3-4 | PD | |
| Cotfix Super Black R | 100 | 4 | 3-4 | 4 | 4 | 3-4 | PD |
D — Dischargeable · PD — Partially dischargeable · ND — Not dischargeable. Understand the table terms.
Which black grade should a buyer choose from the COTFIX table?
The COTFIX Reactive Blacks page compares the six named black dyes in the published table. Black B variants appear in the VS catalogue, and Black PN appears in H/P Printing. All six table entries share solubility of 100 g/L at 30°C and light fastness of 4, while dischargeability splits between dischargeable and partially dischargeable. A buyer should not infer a neutral, blue or red tone, a reactive chemistry or an approval for a particular grade from a name or swatch alone. The table reports the same dry-rubbing value of 4 for every listed black, so the differences to weigh are dischargeability and the wet-rubbing and washing entries.
For printing black shades, Black PN is separately listed in the H/P Printing table, and Black PN is not one of the six entries above. Request a grade-specific tone or application recommendation from Nuchem at Sayakha or Vatva.
How is COTFIX Reactive Blacks consistency held, lot after lot?
Fastness figures are only worth as much as the reproducibility behind the published values. Nuchem describes a three-point quality check, laboratory support and production-lot records across four QC laboratories. Black shades are unforgiving of lot variation, so the test record matters when a buyer runs a long production order. Public checks agree: the 28 September 2026 Gateway review verified 34 active COTFIX products at Control Union Level 3, and OEKO-TEX ECO PASSPORT certificate 21.0.64039 covers 55 COTFIX products with a recorded validity date of 30 June 2027.
Nuchem describes a three-point check before delivery. Review the published quality-control approach and discuss the applicable test records for a selected black grade.
QC labs at the Ahmedabad head office, Ludhiana regional office, and both the Sayakha and Vatva factories.
Nuchem maintains production-lot records for traceability. A separate Gateway check on 28 September 2026 verified 34 active COTFIX products at Control Union Level 3, and a buyer can request the applicable record for a selected grade and lot.
What wastewater treatment does Nuchem publish for dye manufacture?
Nuchem publishes a wastewater-treatment approach built on reverse osmosis, Mechanical Vapour Recompression (MVR) and an Agitated Thin Film Dryer (ATFD). Reverse osmosis recovers water ahead of evaporation, and MVR with ATFD dries the residual stream. Sayakha, the Bharuch plant, runs as a 100% zero liquid discharge operation, so no liquid process effluent leaves the site, and the MVR and ATFD train is rated at 53 kilolitres per day (KLD).
Condensate recovered through the train returns to the manufacturing process, and the dried sludge is sent to Gujarat Pollution Control Board (GPCB) approved Treatment, Storage and Disposal Facility (TSDF) sites. These figures describe the Sayakha plant and must not be extended to Vatva (Ahmedabad) without confirmation. Chemical-product approval of a black grade is separate and does not certify a factory's water-treatment performance; read the water-treatment explanation for the full detail.
Need a sample or a shade match?
Share the shade, substrate and process to discuss grade selection, sample availability and product-specific documents.
Request a sample RR Series — light & medium