Sardarfix™Reactive Dyes
The most technically advanced cotton dyes — forming a permanent covalent bond with cellulose fibres. Outstanding wash fastness. Azo-free certified for global export compliance.
Vinyl Sulphone (VS)
High fixation efficiency, good buildability
Chlorotriazine (MCT)
Cold application, ideal for CPB process
Bifunctional VS + MCT
Superior exhaustion, highest wash fastness
Compatible Substrates
Permanent Covalent Bond with Cellulose
Reactive Dyes are the most technically advanced class of dyes for cotton and cellulosic fibres. Unlike direct or vat dyes, reactive dyes form a true covalent chemical bond with the hydroxyl groups of the cellulose polymer — making the colour a permanent part of the fibre rather than merely deposited within it.
The Sardarfix™ range includes mono-functional (vinyl sulphone or chlorotriazine) and bifunctional reactive dyes, offering flexible application across exhaust, cold pad-batch and continuous processes. The high fixation efficiency minimises hydrolysed dye wastage and reduces wash-off water consumption.
All Sardarfix™ dyes are Azo-free certified with full EU REACH compliance — essential for Pakistan's export-oriented cotton textile manufacturers supplying to European and US markets.
Best Wash Fastness Available
Reactive dyes achieve Grade 4–5 wash fastness (ISO 105-C06) after proper soaping-off — the highest achievable for any dye class on cotton.
Fastness Ratings
Sardarfix™ — Typical Fastness Grades
After thorough soap-off process
Blue Wool scale 1–8
Grades per ISO 105 series. Values are indicative — actual results depend on substrate, shade depth and process parameters.
Technical Properties
Exhaust Dyeing Process (Cotton)
Dissolve the Dye
Dissolve in warm water (40–50 °C). Do NOT use hot water — reactive dyes hydrolyse at high temperatures before fixation. Use soft water for best results.
Set the Dyebath
Add sodium chloride or sulphate (15–60 g/L depending on shade depth) to the dyebath at 40 °C. This promotes dye exhaustion onto the fibre before fixation.
Enter Substrate & Add Dye
Enter pre-wetted cotton at 40 °C. Add dissolved dye gradually over 10–20 minutes while the bath circulates.
Add Alkali (Fixation Phase)
After 20–30 minutes adsorption, add alkali (sodium carbonate) in 2–3 portions over 15–20 minutes to initiate covalent fixation. Do NOT add all alkali at once — it will cause patchy dyeing.
Hold for Fixation
Hold at target temperature (60°C for VS dyes, 40°C for MCT) with alkali present for 45–60 minutes. This ensures maximum covalent bond formation.
Rinse & Soap-Off
Cold rinse → warm rinse → hot soap-off at 95°C with non-ionic detergent (2–3 g/L) for 15–20 minutes → final cold rinse. Thorough soaping is critical for rated wash fastness.
Critical: The soap-off step (Step 6) is non-negotiable for reactive dyes. Hydrolysed dye remains on the fibre surface and bleeds in washing if not removed. Hot soap-off at 95°C ensures the rated fastness is achieved.
Sardarfix™ Colour Range
Fixation rate data and shade cards available on request. Contact us.
Why Azo-Free Matters for Your Business
Our Reactive Dyes are certified free of restricted aromatic amines — the chemical group that has made conventional azo dyes a compliance liability for exporters. Here's what that means for your factory and your customers.
The Chemistry
carcinogenic amines
Safe for humans & export
Azo dyes that release restricted aromatic amines under reductive conditions are banned under EU REACH Annex XVII and equivalent regulations in 30+ countries. Our dye chemistry uses safe chromophore structures — zero restricted amines.
Carcinogenic Amines
Azo dyes containing aromatic amines can cleave to release carcinogenic compounds that penetrate skin and are linked to bladder cancer.
Genotoxic Activity
Several restricted amines exhibit mutagenic and genotoxic activity, damaging DNA in human cells with prolonged skin contact.
30+ Country Ban
Over 30 countries and major trading blocs have banned textiles and leather goods containing restricted azo dyes since the 1990s.
Sardar's Solution
Every dye in our portfolio is rigorously tested — zero restricted aromatic amines. Our customers export to EU, US and Japan with confidence.
Restricted Aromatic Amines (Sample)
Per EU REACH Annex XVII, Appendix 8 — 24 amines restricted in dyes
Export to 30+ Markets with Confidence
Our Azo-Free certification satisfies regulatory requirements across all major export markets
Our 4-Stage Testing Protocol
Every batch of Reactive Dyes passes through rigorous quality control before leaving our factory in Gadoon Amazai, Swabi.
Raw Material Screening
All incoming dye intermediates are screened by HPLC before production begins.
In-Process Control
Samples drawn at each reaction stage are tested for amine content.
Finished Goods Testing
Every batch is tested per EN ISO 14362 / EN ISO 17234 protocols before dispatch.
Third-Party Certification
Independent laboratory testing certificates available on request for export shipments.
Frequently Asked Questions
Why do Reactive Dyes have higher wash fastness than Direct Dyes?
Reactive dyes form a true covalent chemical bond with the hydroxyl groups of the cellulose fibre. This permanent chemical bond (an ether linkage) cannot be washed away — the colour literally becomes part of the fibre. Direct dyes, by contrast, are held by weaker physical forces and can partially wash out.
What is the difference between Vinyl Sulphone (VS) and Chlorotriazine (MCT) reactive dyes?
VS (Vinyl Sulphone) reactive dyes fix at 60°C in alkaline conditions and offer high fixation efficiency. MCT (Chlorotriazine) dyes fix at lower temperatures (40°C) and are suitable for cold-pad-batch (CPB) processes. Bifunctional (VS+MCT) dyes offer superior exhaustion rates. Sardarfix™ includes all three reactive group types.
Why is soaping-off critical for Reactive Dyes?
A portion of reactive dye hydrolyses (reacts with water) rather than fixating on the fibre. This hydrolysed dye sits on the fibre surface and must be removed by a hot soap-off step (95°C with non-ionic detergent). Skipping this step leaves unfixed dye on the fabric which bleeds in washing — giving poor wash fastness readings despite correct dyeing.
Are Sardarfix™ Reactive Dyes suitable for Cold Pad-Batch (CPB) application?
Yes. MCT and bifunctional Sardarfix™ grades are suitable for Cold Pad-Batch (CPB) application — a process where fabric is padded with dye and alkali at room temperature, wrapped in polythene and left to batch for 8–24 hours. CPB is popular for large orders due to lower energy consumption and excellent levelness on light to medium shades.