Direct Blue 71 Manufacturer in India

Trade Name: DIRECT BLUE 2SD  ·  CI Number: Direct Blue 71

Manufacturer: Yobai Industries, Sayakha, Gujarat MOQ: 10 kg Samples: 24 hours Export: Worldwide GST Registered
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Overview

Direct Blue 71 — Product Overview

Direct Blue 71 has held a specific and important role in the direct dye segment for decades — it is the standard blue component in trichromatic direct dyeing of cotton and viscose. When a dyehouse runs a three-dye system to achieve the full commercial shade gamut on cellulosic substrates, Direct Blue 71 is overwhelmingly the blue they reach for. The reason is its combination of consistent exhaustion behaviour, good levelness across machine types, and reliable compatibility with direct reds and yellows in the same bath.

In single-dye applications it gives a clean medium blue — slightly towards the greenish side compared to some reactive blues, which is actually preferred in certain home textile and furnishing shade cards where a pure cold blue would look out of place. On paper substrates it performs well at low concentrations, which is why it appears in packaging, stationery, and decorative tissue colouring globally. Yobai Industries supplies it as DIRECT BLUE 2SD, tested for shade strength and dissolution rate on every batch. CAS 4399-55-7.

Applications

  • Trichromatic direct dyeing of cotton and viscose (standard blue component)
  • Cotton woven and knit fabric — medium to deep blue shades
  • Viscose and rayon dyeing
  • Linen and jute dyeing
  • Paper pulp and surface colouring
  • Canvas and non-woven fabric dyeing
Substrates

Suitable For

  • Cotton (woven and knit)
  • Viscose / Rayon
  • Linen and Jute
  • Paper and cellulosic substrates
Benefits

Key Benefits

  • Industry-standard blue for trichromatic direct dyeing
  • Excellent levelness and migration at 90–100°C
  • High compatibility with direct reds and yellows in combination baths
  • Consistent exhaustion behaviour — reliable shade reproducibility
  • No mordant or alkali required — simple neutral salt bath
  • Wash fastness upgradeable to 4 with cationic fixative after-treatment
Technical Specifications

Direct Blue 71 — Technical Specifications

Specifications are indicative. Contact us for a batch-specific TDS before placing a bulk order.

ParameterValue
Product NameDirect Blue 71
Trade NameDIRECT BLUE 2SD
CI NumberDirect Blue 71
CAS Number4399-55-7
Molecular Weight~1029 g/mol
Dye ClassDisazo Direct Dye (Anionic)
ColourMedium Blue
AppearanceBlue to Blue-Green Powder
Ionic CharacterAnionic (tetrasulphonate groups)
SolubilitySoluble in hot water (40–60°C); 30–50 g/L
Application pH7–8 (neutral); slight alkalinity (pH 8–9) acceptable
Application Temp.90–100°C
Required AuxiliariesNaCl 20–40 g/L or Na₂SO₄ 20–50 g/L; no acid or alkali fixation required
Wash Fastness3–4 (4 with cationic fixative)
Light Fastness4
Packaging1 kg · 5 kg · 10 kg · 25 kg · 50 kg · Custom packaging available
Shelf Life5 years from manufacture (cool, dry storage)
ManufacturerYobai Industries, Sayakha, Gujarat, India
GSTINGST Registered

Need a full TDS, COA, or MSDS? Request it here or WhatsApp us directly.

Chemical Properties

Chemical Identity & Dyeing Performance

Chemical Identifiers

CAS Number4399-55-7
CI NumberDirect Blue 71
Molecular Weight~1029 g/mol
Chromophore TypeDisazo
Ionic CharacterAnionic (tetrasulphonate)
Bond with FibrePhysical adsorption (H-bond + Van der Waals)

Dyeing Performance

Application Temperature90–100°C
Application pH7–8 (neutral bath)
ElectrolyteNaCl 20–40 g/L or Na₂SO₄ 20–50 g/L
LevelnessExcellent — good migration at boil
Wash Fastness (base)3–4 (ISO 105-C06)
Wash Fastness (treated)4 (with cationic fixative)

The four sulphonate groups on Direct Blue 71 give it high water solubility and strong anionic character, both of which contribute to its excellent leveling behaviour. Batch-specific COA with shade strength and solubility data available on request.

Physical Properties

Physical & Colour Fastness Properties

PropertyValue / Rating
Physical FormBlue to blue-green powder
Bulk DensityApprox. 0.35–0.55 g/cm³
Solubility in Water30–50 g/L at 40–60°C; lower at room temperature
Bath StabilityStable at neutral to mildly alkaline pH (7–9) at 90–100°C
Wash Fastness (ISO 105-C06)3–4 (4 with cationic fixative)
Light Fastness (ISO 105-B02)4
Rubbing Fastness — Dry3–4
Rubbing Fastness — Wet3
Perspiration Fastness3–4
Chlorine Fastness2–3 (avoid chlorine-bleached substrates)
Levelness / MigrationExcellent (good migration rate at 90–100°C)

Fastness on 1–5 scale (5 = best). Cationic fixative treatment recommended for apparel and home textile end-uses. Batch COA with fastness data available on request.

Solubility

Solubility & Dissolution Guidelines

Solubility is moderate at room temperature — around 20–30 g/L — and climbs to 30–50 g/L at 40–60°C. That range is comfortable for all commercial shade depths up to 5% owf. Always pre-dissolve before adding to the bath. The standard method: make a cold paste with a small volume of cold water first, then bring up to 50–60°C with continuous stirring. Adding the powder directly to a hot, salt-laden bath is a shortcut that causes unevenness — undissolved particles deposit on the fabric surface, and at the dyeing temperature they don't redistribute the way you'd hope.

For trichromatic combination dyeing, dissolve each dye component separately before combining in the bath. This avoids any precipitation from ionic interactions between components at high concentration.

Dissolution Best Practices

  • Paste the powder in cold water first, then raise to 50–60°C
  • Stir continuously — do not allow the dissolving vessel to stand static
  • Filter through 100-mesh screen before adding to main bath
  • For trichromatic dyeing, dissolve each component separately
  • Avoid strongly acidic or alkaline dissolution water (pH 5–9 is acceptable)
  • Use dissolved solution within 8 hours for best results
Recommended Dosage

Exhaust Dyeing — Dosage Guide by Shade Depth

Values for cotton exhaust dyeing at liquor ratio 1:10–1:15. Add salt in 2 portions for level results. Na₂SO₄ may be substituted for NaCl at equivalent ionic strength.

Shade Depth Dye (%owf) NaCl (g/L) pH Temp (°C) Time (min)
Pale Blue0.3–0.8%10–157–890–10030–40
Medium Blue1–2%20–257–890–10045
Deep Blue2.5–4%25–357–990–10045–60
Navy / Dark Blue4–6%30–408–990–10060

Process Notes

  • Temperature ramp: Start at 40°C, ramp to 90–100°C over 20–30 minutes. Direct Blue 71's good migration rate means it will level well even if initial strike is uneven, provided there is sufficient time at temperature.
  • Salt choice: Both NaCl and Na₂SO₄ work. Na₂SO₄ gives slightly more controlled strike at the start — useful on fine-count knits where sudden exhaustion causes barriness.
  • Cationic fixative: After dyeing and rinsing, treat at 40°C with a cationic fixative (2–3% owf, 20 min). Improves wash fastness to 4. Rinse cold after fixation.
  • Trichromatic dyeing: Pair with a compatible direct red and direct yellow. Match exhaustion rates between components for reproducible combination shades — contact our technical team for recommended pairings.

Contact our technical team at technical@yobaiindustries.in for trichromatic recipe development and process support.

Available Shades

Blue Depth Options — Direct Blue 71

Direct Blue 71 produces a consistent medium-to-deep blue with a slight greenish character on mercerised cotton. Shade depth is controlled by dye concentration.

Pale Blue
0.3–0.8% owf
Medium Blue
1–2% owf
Deep Blue
2.5–4% owf
Navy / Dark Blue
4–6% owf

Shade has a slightly greenish-blue character — a property that makes it particularly suitable for combination trichromatic recipes. Request a lab dip for colour-critical work.

Packaging

Packaging Options

All packs sealed in multi-layer moisture-proof bags. Custom packaging and private labelling available for bulk buyers.

1 kg
Lab / Trial Sample
5 kg
Small Batch / Pilot
10 kg
MOQ — Standard
25 kg
Regular Production
50 kg
Large Production Run
Custom
Bulk / OEM Packing

All shipments include batch-specific COA. Export packing (UN-certified drums) available on request.

FAQ

Frequently Asked Questions — Direct Blue 71

Its exhaustion behaviour is consistent and predictable across a wide range of water qualities and machine types. When you're trying to match shades in a three-dye combination, inconsistency in one component throws the whole recipe out. DB71 has earned the standard-component position because dye houses have built years of recipes around it and it hasn't let them down. Its levelness is also genuinely good — it migrates well at 90–100°C which corrects for early uneven strike before you lock the shade in.

Yes — a cationic fixative after-treatment at 40°C improves wash fastness by approximately 0.5–1 grade, taking it from 3–4 to 4. The fixative works by forming an ionic interaction with the anionic dye on the fibre surface, reducing the amount that bleeds in subsequent washes. It doesn't convert the bond type — the dye is still physically held — but it reduces bleed enough to make a meaningful difference for apparel applications. Skip it for paper, jute, and applications where washability is not a requirement.

Yes. Na₂SO₄ (Glauber's salt) is interchangeable with NaCl for direct dye exhaustion, and both work with Direct Blue 71. The practical difference is that Na₂SO₄ tends to give a slightly slower, more controlled initial strike — useful when dyeing fine knitwear or light-weight fabrics where a sudden electrolyte shock causes barriness. For woven cotton at standard weights, either works equally well. Use equivalent ionic strength as the conversion point — generally 1.5–2× the mass of Na₂SO₄ vs NaCl for equivalent electrolyte effect.

Yes — Direct Blue 71 is the standard blue in trichromatic direct dyeing systems precisely because of its broad compatibility with anionic direct reds and yellows. The key compatibility criterion is matched exhaustion rates — if one component exhausts significantly faster than the others, the shade shifts during the run and you lose reproducibility. Our technical team can recommend specific Direct Red and Direct Yellow grades from our range that pair well with DB71 for consistent combination shade results.

Very well. Direct Blue 71 has strong affinity for cellulosic paper fibres and gives clean, even blue colouration at low dosage levels (0.1–1% on dry paper weight). It can be added to the pulp slurry at beater stage or applied via surface application, depending on the process. No salt or pH adjustment is typically required for pulp dyeing. The shade is stable in the neutral pH range typical of modern paper mills. It's used globally in stationery, packaging, tissue, and decorative paper production.

The greenish-blue character comes from its disazo chromophore system — the absorption maximum sits at a wavelength that reflects slightly into the green-blue region of the spectrum. In practice this is actually an advantage for trichromatic combination shades where a neutral, slightly cool blue is needed as a base. If you need a warmer, more violet-blue shade, Direct Blue 85 is the grade to consider — it has a different shade character. If you need both, we can advise on blending ratios.

90–100°C, same as woven cotton — the target temperature is determined by the dye's diffusion requirements into the cotton fibre, not by the fabric construction. The process difference for knits is in the salt addition and heating rate. Add salt more gradually (3 portions instead of 2) to slow the initial strike, and ramp temperature more slowly (30–40 minutes to reach 90°C instead of 20). Both measures reduce the risk of uneven initial exhaustion that shows as barriness on tubular knitwear.

Minimum order is 10 kg. Sample quantities (1–5 kg) dispatched within 24 hours. Bulk orders in 7–15 working days. Export handled routinely — contact us with destination for freight terms and documentation requirements.

Choose Direct Blue 71 when the wash fastness specification is 3–4 (achievable without a fixative) or 4 (achievable with a cationic fixative), the substrate is cotton, viscose, linen, jute, or paper, and process simplicity matters — no alkali, no fixation chemistry, just salt and heat. For wash fastness of 4–5 or better, or where the customer specification explicitly calls for reactive dye, switch to the reactive blue range. For trichromatic combination dyeing where all three components need to be matched in terms of process conditions, Direct Blue 71 is the natural choice because it's specifically designed for that system.
Storage

Storage & Handling

Store below 30°C in a dry location with relative humidity below 65%. Moisture is the primary risk for powder direct dyes — even partial absorption degrades solubility and can cause the powder to cake, which makes accurate weighing difficult and dissolution inconsistent. Seal bags immediately after every weighing. Keep away from acids, oxidising agents, and chlorine compounds, all of which cause irreversible shade degradation. Direct sunlight causes colour shift over time — covered indoor storage is essential.

Shelf Life: 5 Years
Guaranteed from date of manufacture under recommended storage conditions (below 30°C, RH below 65%, sealed containers). After 5 years, verify shade strength on a lab trial before production use. Manufacturing date is stated on all Yobai Industries COAs.

Handling Precautions

  • Wear gloves and dust mask during weighing and handling
  • Avoid inhalation of fine powder — use enclosed weighing areas where possible
  • Reseal containers immediately after use
  • Do not store near bleaching agents or oxidising chemicals
  • Request MSDS from Yobai Industries for full safety data
Industries Served

Who Uses Direct Blue 71?

Direct Blue 71 is used wherever a reliable, reproducible blue is needed on cellulosic substrates without reactive dye process requirements. Contact us for grade recommendations specific to your application.

Cotton & Viscose Textiles
Paper & Packaging
Canvas & Jute
Home Furnishings
Available Grades

Direct Dyes — Available Grades

Yobai Industries carries the following grades in this dye family. Click any grade to view specifications, or view the full catalogue →

Direct Black 22 Direct Black 80 Direct Blue 290 Direct Blue 71 (This Grade) Direct Blue 85 Direct Green 38 Direct Orange 39 Direct Red 23 Direct Red 79 Direct Yellow 142

Don't see the grade you need? We carry 250+ dye grades. Contact us and we'll source or develop it for you.

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Reactive vs Direct Dyes Guide
Technical guide — application advice & grade selection
Need COA, MSDS or application guidance? Contact our technical team — technical@yobaiindustries.in

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MOQ 10 kg · Samples in 24 hours · Bulk in 7–15 days · Export worldwide · GST invoice with every order.

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