Reactive dyes: eight COTFIX series,
compared by process and shade.
COTFIX® reactive dyes are manufactured at Sayakha and Vatva for cotton, viscose and other cellulosics. Each series is built for a different combination of process, shade depth and fastness requirement — this page explains which one fits which job.
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.
Which COTFIX series fits which process and shade?
Nuchem's eight COTFIX series separate reactive dyes by process and shade requirement. COTFIX VS is the vinyl sulphone range for exhaust, cold pad batch, continuous dyeing and printing; COTFIX ME is the VS-MCT bifunctional range for lower-temperature processing; COTFIX HE is bis-monochlorotriazine for high-fixation exhaust dyeing at 80–95°C, and COTFIX RGB offers one-tone build-up for warm dyeing and padding. COTFIX D addresses deep shades, COTFIX RR very light and medium shades, COTFIX Blacks six listed reactive blacks, and COTFIX H/P Printing prolonged printing and steaming. The eight series publish 58 catalogue rows, with VS listing 10 shades, ME seven, HE twelve, RGB four, D four, RR three, Blacks six and H/P Printing twelve. Exact grade data and approval coverage remain separate checks. Selection depends on fibre, shade depth and the process the mill runs. Confirm the chosen grade against the published fastness and solubility tables. Grade-level approval coverage is checked separately for each order.
Which COTFIX series fits deep shades, lower-temperature dyeing or prolonged printing?
Nuchem positions COTFIX D for deep shades on cellulosic fibres, COTFIX ME for lower-temperature dyeing, and COTFIX H/P Printing for prolonged printing and steaming. Each serves a different selection need. Compare the named shades and their published fastness and solubility values on each series page. Confirm the chosen grade's approval documents separately before use.
What do D, PD and ND mean?
In Nuchem's COTFIX tables, D means dischargeable, PD means partially dischargeable and ND means not dischargeable. These labels describe the listed shade's discharge behaviour; they are different from the name of the COTFIX D Series. For example, Blue RR is marked D while Red RR is marked ND. The labels do not provide a process recipe or establish certification coverage. Solubility is listed at 30°C; gpl means grams per litre. Compare each shade's light, washing and rubbing values separately.
Read the step-by-step guide to comparing fastness and solubility data.
| Series | Reactive system | Best for | Shades |
|---|---|---|---|
| COTFIX VS | Vinyl sulphone | Warm dyeing; exhaust, CPB, continuous, printing | 10 |
| COTFIX ME | VS-MCT bifunctional | Lower-temperature, high-exhaustion dyeing | 7 |
| COTFIX HE | Bis-monochlorotriazine | High fixation by exhaust at 80–95 °C | 12 |
| COTFIX RGB | One-tone build-up | Warm dyeing and padding | 4 |
| COTFIX D | Dark series | Deep-shade selection; compare individual grade data | 4 |
| COTFIX RR | Modified speciality | Very light and medium shades | 3 |
| COTFIX Blacks | Six listed reactive blacks | Black shades; shade-specific dischargeability | 6 |
| COTFIX H/P Printing | Monochlorotriazine | Prolonged printing and steaming cycles | 12 |
Full fastness data — solubility, rubbing dry and wet, light fastness and washing fastness — is published for 58 catalogue rows across eight series on the product tables.
The eight series in detail
VS Series — vinyl sulphone
Vinyl sulphone reactive dyes for cellulosic fibres, including cotton and viscose. The ten listed shades cover exhaust, cold pad batch, continuous dyeing and printing. Compare the particular shade's fastness and solubility instead of assuming one whole-range performance rating.
ME Series — VS-MCT bifunctional
A bifunctional range combining vinyl sulphone and monochlorotriazine reactive-group types. The seven listed shades are positioned for lower-temperature processing, including exhaust, cold pad batch and continuous dyeing. Confirm conditions for the selected shade; this is not a complete process recipe.
HE Series — high exhaust, 80–95 °C
Twelve listed bis-monochlorotriazine shades for exhaust dyeing at the published 80–95°C range. Read the separate solubility and fastness values for each shade. That application temperature alone does not define dosing, fixation percentage or a universal result.
RGB Series — one-tone build-up
Four listed grades for one-tone build-up in warm dyeing and padding. Compare their individual fastness and solubility values. Where colour matching under different light sources matters, discuss the intended viewing conditions rather than assume a universal match.
D Series — deep shades
Four listed shades developed for deep-shade selection, each with individual washing and rubbing values. Compare the table with RR for very light and medium shades. The catalogue does not establish a universal dosing or cost saving against other reactive dye classes.
RR Series — light and medium shades
Three listed shades for very light and medium shades. Yellow RR is partially dischargeable, Red RR is not dischargeable and Blue RR is dischargeable. Compare the chosen row's other fastness properties; this description is not a low-dose recipe.
Blacks — Six listed reactive blacks
Six listed reactive black dyes with grade-specific solubility, fastness and dischargeability data. Black B variants are separately listed in VS, while Black PN is listed in H/P Printing. Ask for the exact grade's tone and application guidance rather than inferring it from a family name.
H/P Printing Series — monochlorotriazine
Twelve listed monochlorotriazine shades for prolonged printing and steaming. Nuchem describes mixability with VS; confirm the actual grades and process conditions before mixing. H/P is distinct from the lower-temperature ME dyeing range.
How does each dyeing process select a COTFIX series?
Reactive dyes bond covalently to the hydroxyl groups in cellulose, which is why the colour survives repeated washing rather than sitting on the fibre surface. The reactive system and the application temperature separate the eight COTFIX series. In exhaust dyeing, fabric or yarn circulates in a dyebath while dye moves onto the fibre, and the high-exhaust bis-monochlorotriazine range is specified for fixation at 80–95°C. Cold pad batch pads dye and alkali onto fabric, then batches at ambient temperature for several hours, a route served by COTFIX VS and COTFIX ME. Continuous dyeing favours reproducibility across long runs, where COTFIX RGB adds one-tone build-up. The COTFIX HE range handles exhaust work, while printing and steaming hold print paste under sustained heat and alkali, favouring the monochlorotriazine COTFIX H/P Printing range and the vinyl sulphone VS range. Confirm conditions for the selected grade before use.
Exhaust dyeing
The batch process most mills run — fabric or yarn circulating in a dyebath while dye exhausts onto the fibre. HE is purpose-built for it at 80–95 °C with high fixation efficiency. ME is positioned for lower-temperature processing; actual energy use depends on the process. VS and RGB both run exhaust comfortably.
Cold pad batch (CPB)
Padding dye and alkali onto fabric, then batching at ambient temperature for several hours. Economical on energy and water, but it demands dyes with alkali stability and predictable build-up. VS and ME are the two series specified for it.
Continuous dyeing
Long runs at speed, where reproducibility across metres matters more than anything else. VS, ME and RGB all run continuous — RGB in particular for its one-tone build-up, which keeps shade consistent as concentration varies.
Printing and steaming
Print paste sits on fabric far longer than dye sits in a bath, and steaming applies sustained heat and alkali. That punishes reactive dyes with high reactive character. The H/P Printing series is monochlorotriazine precisely for this — high substantivity and alkali stability through prolonged cycles. VS Series also covers printing; confirm grade-specific compatibility with H/P Printing.
Where are Nuchem COTFIX reactive dyes manufactured?
COTFIX® reactive dyes are manufactured at Unit 1 in Sayakha, Bharuch and Unit 2 in Vatva, Ahmedabad, with in-house laboratories at both factories plus the Ahmedabad head office and a regional laboratory in Ludhiana. Review the published quality-control and lot-traceability approach, then discuss the relevant grade and lot records with Nuchem. The two Gujarat sites handle different production needs, and site-specific capability is confirmed for each requirement before an order.
Nuchem publishes a water-treatment approach for reverse osmosis, MVR and ATFD at the sites, and separates site evidence from the product-specific approvals. A buyer can check the published quality and environmental information, request applicable site evidence and confirm the document set for a selected COTFIX grade before ordering. Manufacturing, quality control and approval are separate scopes, so a series name never substitutes for a document check for the order.
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