Trade Name: REACTOBOND BLACK HN · CI Number: Reactive Black 8
Reactive Black 8 is a monochlorotriazine (MCT) reactive dye formulated specifically for textile printing on cotton and viscose. Where its better-known cousin Reactive Black 5 is the go-to choice for exhaust dyeing, RB8 is the printing room's black — it's designed around the printing paste system, with the MCT reactive group providing the right balance of stability in the paste and reactivity under steam fixation. You can formulate a printing paste with RB8, hold it at production temperatures all day, and it won't pre-react in the thickener the way a more reactive VS-type black would. That practical stability is the main reason it's been a standard in screen and rotary printing for decades.
At Yobai Industries we supply it as REACTOBOND BLACK HN. Shade strength and fixation efficiency are checked on every batch — printers working to tight shade standards rely on consistent dye strength, and a lot variation between batches makes colour management impossible. Steam fixation at 100–103°C for 8–12 minutes completes the permanent covalent bond with cellulose, giving wash fastness that flat-out beats what you'd get from a pigment print of equivalent depth. It can also be run in exhaust dyeing where a slightly higher-temperature process is available, though exhaust is not its primary application.
Specifications are indicative. Contact us for a batch-specific TDS before placing a bulk order.
| Parameter | Value |
|---|---|
| Product Name | Reactive Black 8 |
| Trade Name | REACTOBOND BLACK HN |
| CI Number | Reactive Black 8 |
| CAS Number | Available on request |
| Colour | Black |
| Appearance | Black Powder |
| Ionic Character | Anionic (sulphonate groups) |
| Molecular Weight | Approx. 1084 g/mol |
| Dye Class | Monochlorotriazine (MCT) Reactive (Disazo) |
| Solubility | Soluble in water; pre-dissolve at 40–50°C before adding to paste |
| Application pH | 7–8 (printing paste); 10–11 (exhaust dyeing) |
| Application Temp. | 100–103°C steam fixation (printing); 80°C (exhaust) |
| Required Auxiliaries | Printing: sodium alginate thickener + urea 50–100 g/kg + NaHCO₃ or Na₂CO₃ 15–25 g/kg. Exhaust: NaCl 40–60 g/L + NaOH or Na₂CO₃. |
| Fixation Yield | 65–75% (steam fixation, optimised conditions) |
| Exhaustion Rate | 65–70% (exhaust dyeing at 80°C) |
| Wash Fastness | 4 |
| Light Fastness | 4–5 |
| Packaging | 1 kg · 5 kg · 10 kg · 25 kg · 50 kg · Custom packaging available |
| Shelf Life | 5 years from manufacture (cool, dry storage) |
| Manufacturer | Yobai Industries, Sayakha, Gujarat, India |
| GSTIN | GST Registered |
Need a full TDS, COA, or MSDS? Request it here or WhatsApp us directly.
Fixation yield and exhaustion rates are indicative values under standard laboratory conditions. Results vary by steamer type, steam quality, fabric construction, and process control. Contact Yobai Industries for application-specific support.
| Property | Value / Rating |
|---|---|
| Physical Form | Fine black powder |
| Bulk Density | Approx. 0.4–0.6 g/cm³ (varies by grade) |
| Solubility in Water | Soluble; dissolve at 40–50°C before adding to paste |
| Paste Stability | Stable in neutral alginate paste at room temperature for 24–48 hrs |
| Wash Fastness (ISO 105-C06) | 4 |
| Light Fastness (ISO 105-B02) | 4–5 |
| Rubbing Fastness — Dry | 4 |
| Rubbing Fastness — Wet | 3–4 |
| Perspiration Fastness (Acid) | 4 |
| Perspiration Fastness (Alkaline) | 4 |
| Print Sharpness | Excellent — minimal bleeding at fine line widths |
| Colour Build-up | Good up to full depth; depth limited vs bifunctional grades |
Fastness ratings are on the standard 1–5 scale (5 = best). Values are achieved after proper hot soaping at 95°C post-printing. Batch-specific COA with fastness data available on request.
Reactive Black 8 dissolves well in warm water at 40–50°C. For printing paste preparation, always pre-dissolve the dye in a small volume of warm water before adding to the thickener — adding dry powder directly to alginate paste gives you undissolved particles that block screens and leave spots on the print. The dye solution should be clear and uniform before you incorporate it.
Urea at 50–100 g/kg in the paste acts as a humectant during steaming — it keeps the paste film moist under steam, which directly improves penetration and fixation. Don't skip it on heavy-weight fabrics. Add the alkali (NaHCO₃ for milder conditions, Na₂CO₃ for fuller depth) last, only when the paste is going to be used within a few hours. Alkaline paste sitting overnight begins to hydrolyse, and you lose fixation yield.
All values are for reactive printing paste using sodium alginate thickener. Steam fixation at 100–103°C in saturated steam. Urea 50–100 g/kg included in all paste formulations.
| Print Depth | Dye (g/kg paste) | Urea (g/kg) | Alkali (g/kg) | Steam Temp (°C) | Steam Time (min) |
|---|---|---|---|---|---|
| Light Tone | 10–20 | 50 | NaHCO₃ 15 | 100–103 | 8 |
| Medium Tone | 30–50 | 75 | NaHCO₃ 20 | 100–103 | 10 |
| Dark Tone | 60–80 | 100 | Na₂CO₃ 20–25 | 100–103 | 10–12 |
| Full Depth / Solid | 90–120 | 100 | Na₂CO₃ 25 | 100–103 | 12 |
Contact our technical team at technical@yobaiindustries.in for process optimisation specific to your printing machines and steamer type.
Reactive Black 8 produces a range of black depths depending on dye concentration in the printing paste. The following depths are achievable with standard sodium alginate paste on cotton under saturated steam fixation.
Actual depth achieved depends on fabric weight, thickener concentration, steamer quality, and wash-off thoroughness. Request a lab print strike-off for colour-critical work.
All packs are sealed in multi-layer moisture-proof bags. Custom packaging and private labelling available for bulk buyers.
All shipments include batch-specific COA. Export packing (UN-certified drums) available on request.
Store below 25°C in a dry location with relative humidity below 60%. MCT reactive dyes are more stable than VS-type in storage, which is one reason they're preferred in printing — they tolerate more variation in warehouse conditions without fixation yield dropping. But moisture is still the main risk. A partially open bag in a humid weighing area will degrade over time — seal the bag after every weighing, not at the end of the day. Store away from acidic materials and oxidising agents, which cause irreversible colour change. Keep away from direct sunlight and heat sources.
This dye is used by manufacturers across the following industries. Contact us with your specific application for a grade recommendation.
Yobai Industries carries the following grades in this dye family. Click any grade to view specifications, or view the full catalogue →
Don't see the grade you need? We carry 250+ dye grades. Contact us and we'll source or develop it for you.
MOQ 10 kg · Samples in 24 hours · Bulk in 7–15 days · Export worldwide · GST invoice with every order.