Section
| HS Code | 422562 |
| Productname | Direct Violet N |
| Colorindexname | C.I. Direct Violet 1 |
| Colorindexnumber | 22570 |
| Casregistrynumber | 2586-60-9 |
| Dyeclass | Direct dye |
| Appearance | Dark violet powder |
| Watersolubility | Soluble in water |
| Solutioncolor | Violet |
| Application | Dyeing of cotton, viscose, paper and leather |
| Lightfastness | Moderate |
| Washingfastness | Moderate |
| Storageconditions | Store in a dry, cool, ventilated place |
As an accredited Direct Violet N factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Direct Violet N is packaged in 25 kg net multi-walled paper bags with polyethylene liners, sealed and labeled for industrial use. |
| Container Loading (20′ FCL) | Direct Violet N packed in sealed drums, palletized, evenly distributed and secured inside a clean, dry 20-foot FCL. |
| Shipping | Direct Violet N is typically shipped as a non-hazardous general chemical unless otherwise specified, in sealed, clearly labeled containers protected from moisture, direct sunlight, and contamination. Transport according to the supplier’s SDS and local regulations; avoid damage, spillage, and contact with incompatible materials. Keep containers closed and upright during transport. |
| Storage | Store Direct Violet N in a cool, dry, well-ventilated area away from direct sunlight, heat, and ignition sources. Keep containers tightly closed and properly labeled to prevent moisture absorption, contamination, and dust generation. Segregate from strong oxidizers, acids, and alkalis. Use secondary containment where appropriate, avoid storing near foodstuffs, and follow the manufacturer’s safety data sheet for specific requirements. |
| Shelf Life | Direct Violet N shelf life is typically two years when stored cool, dry, dark, and well-ventilated in tightly closed containers. |
Exhaust dyeing of bleached cotton knitwear with Direct Violet N in a soft-flow overflow machine proceeds through a staged salt-addition sequence rather than a single electrolyte dump. The dye is pasted with cold demineralized water and dissolved at 70–80°C under mechanical agitation; the solution is filtered through a 50 μm screen before entering the dosing tank. Dyeing is initiated at 30–40°C with a liquor ratio of 1:8 to 1:15 and an initial sodium sulfate dose of 0.5–1.0 g/L. The bath is raised to 60°C at 1.0–1.5°C/min, held for 10–15 min, and then a second sodium sulfate dose of 5–15 g/L is added in three equal increments over 20–30 min. Fabric rope circulation is maintained at 180–280 m/min; overloading above 80% of nominal machine capacity reduces levelness on long batches. Exhaustion is completed at 90–95°C for 30–45 min, after which the bath is cooled to 60°C before sampling. Water hardness above 150 ppm CaCO₃ requires a polyphosphate or polyacrylic acid sequestrant at 1–2 g/L to prevent dye aggregation and filter blocking. After dyeing, the exhausted bath is dropped, and aftertreatment with a cationic fixative at 1–3% o.w.f. is run in a fresh bath at 40–50°C and pH 5.0–6.0 for 20 min. The terminal product is pale-to-medium violet cotton knitwear for lining, loungewear and craft fabrics where wash fastness requirements are moderate. Batch-to-batch uptake variation on cotton lots with differing maturity is a known production bottleneck, and the salt curve is adjusted after laboratory dyeing rather than fixed.
| Test method | Standard designation | Property verified |
|---|---|---|
| Colour fastness to domestic and commercial laundering | ISO 105-C06:2010 | Shade change and staining of multifibre adjacent fabric |
| Colour fastness to rubbing | ISO 105-X12:2016 | Dry and wet crocking |
| Colour fastness to artificial light | ISO 105-B02:2014 | Xenon arc exposure against blue wool references |
| Colour fastness to perspiration | ISO 105-E04:2013 | Acid and alkaline perspiration shade change and staining |
| Colour fastness to water | ISO 105-E01:2013 | Water immersion shade change and staining |
| Laundering for export to United States | AATCC TM61-2013 | Accelerated laundering, shade change and staining |
Papermaking wet-end application of Direct Violet N involves anionic competition with fibre fines, filler and alum; dulling in alum-rich systems is frequently traced to aluminium residuals in the white water rather than dye decomposition. The dye is metered into thick stock at 3.0–4.0% consistency after refining and before retention aid addition. Typical addition is 0.05–0.5% on dry fibre. Alum is used at 0.5–2.0 kg/ton for rosin sizing or pH control; when tray water aluminium exceeds 2–5 mg/L, the anionic dye can precipitate onto fibre surfaces and shift the shade dull or uneven. A cationic polyacrylamide retention aid at 0.02–0.05% on dry fibre is added after the dye has circulated for 10–15 min. The wet-end pH is maintained at 4.8–6.2. The terminal paper and board grades include coloured tissue, folder stock and mattress label board. Compliance for food-contact grades is restricted to EU Regulation EC 1935/2004 and FDA 21 CFR 176.170 only after migration testing, because published data for Direct Violet N in this specific configuration is limited. For deep violet grades, broke recycling returns unfixed dye to the wet end, raising conductivity and reducing first-pass retention; backwater colour is monitored with a spectrophotometer rather than visually.
In continuous pad-steam ranges processing woven cellulosic fabric at 40–80 m/min, Direct Violet N is applied from a pad trough containing wetting agent, sodium sulfate and anti-migration agent. The pad liquor is prepared by dissolving the dye separately at 70–80°C and adding it to cold water to reach a final concentration of 10–30 g/L. Sodium sulfate is held at 5–10 g/L to reduce selective migration during drying; anti-migration agent, typically a polyacrylamide or guar derivative, is applied at 5–15 g/L, but overdose causes edge marks and dyestuff aggregation. The fabric is padded to 65–80% wet pick-up, pre-dried in an infrared or hot-air zone, and steamed at 100–102°C for 30–90 s to complete diffusion. Wash boxes run a cold rinse followed by a hot soaping stage at 60–80°C and a final cold rinse; unfixed dye bleed during washing is inherent to direct dye chemistry. The terminal product is violet woven lining, pocketing and low-cost shirting fabric. Wet fastness after fixation is verified with ISO 105-C06:2010 and ISO 105-X12:2016. Compliance for apparel restricted-substance lists requires a certificate of analysis confirming the absence of listed aromatic amines under the reductive-cleavage conditions referenced in EU REACH Annex XVII entry 43 where applicable.
In aniline and semi-aniline leather finishing, Direct Violet N is dissolved and filtered before incorporation into water-dilutable base coats to maintain transparency of the grain pattern. The dye solution is prepared at 5–10% solids in demineralized water and passed through a 10–25 μm filter mesh; undissolved particles produce specking on corrected grain. It is added at 0.05–0.5 wt% of the aqueous finish formulation based on wet weight, alongside casein or acrylic emulsion binders. The finish pH is kept at 7.0–8.5; acidification below 4.5 in the presence of cationic waxes or retanning residues can precipitate the anionic dye. Application uses a spray gun at 3.5–5.0 bar atomizing air, applied in 2–4 cross-coats with intermediate drying at 45–60°C, followed by plating at 80–100°C and 50–100 bar. The terminal leather types are full-grain aniline footwear and briefcase leathers where a transparent violet tint is required. Rub fastness is assessed under ISO 11640:2012; lightfastness is typically the limiting factor, and UV absorbers may be needed. Published data for Direct Violet N specific lightfastness in this finish configuration is limited.
Aqueous flexographic ink concentrates for absorbent board and tissue can be tinted with Direct Violet N where high crocking resistance is not required. The dye is dissolved in a water/co-solvent system with propylene glycol or diethylene glycol at 5–10 wt%, and the concentrate is normalized to 5–15 wt% dye solids. pH is adjusted with triethanolamine or dilute ammonia to 7.5–9.0; alkaline pH stabilizes the dye against precipitation with acidic binders or rosin-modified resins. The press-ready ink is diluted to a viscosity of 18–25 s Zahn #2 cup. Printing on uncoated recycled board with a Cobb value of 20–80 g/m² according to ISO 535:2014 produces high strike-through risk; a cationic starch or acrylic overprint varnish is used to seal the dye surface. Terminal products are printed napkin bands, paperboard overwrap and decorative tissue where wet-contact fastness is not specified. For indirect food-contact packaging, compliance requires migration testing under EC 1935/2004 and, for the German market, BfR Recommendation XXXVI; published data for Direct Violet N as a paper ink colorant is limited.
Because oxidized starch backwater contains anionic starch fragments and coating broke, Direct Violet N addition to the size press is controlled by backwater anionic demand rather than dye concentration alone. Surface sizing with Direct Violet N on fine paper and linerboard is carried out by adding the dye to oxidized corn starch or enzymatically converted starch at 6–10% solids. The starch solution is held at 55–65°C at the size press; dye addition is 0.05–0.3% on dry starch solids. Direct Violet N is dissolved separately and injected into the starch line after the enzyme deactivation point to avoid thermal degradation and colour drift. The size press operates at 80–120 m/min sheet speed with a nip load sufficient to give 1.0–1.5 g/m² dry starch pickup per side. Backwater colour intensity does not scale linearly with dye concentration because the anionic dye accumulates in the return starch loop and competes with starch adsorption. The controlling variable is the anionic demand of the backwater: high levels of oxidized starch fragments and coating broke increase conductivity and diminish dye retention. Cationic starch and Direct Violet N are not combined in the same storage tank; precipitation occurs when the cationicity exceeds the dye solubility margin. The terminal product is violet-tinted envelope and file folder stock where surface colour and waterfastness are secondary. Optical density is checked against a reference drawdown and brightness is verified with ISO 2470-1:2016.
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Direct Violet N is the commercial designation for the water-soluble disazo dye classified as C.I. Direct Violet 1 under Colour Index Constitution Number 22570. The product is supplied as a dark violet-to-black homogeneous powder standardized with sodium sulfate or sodium chloride to a tinctorial strength of 100% relative to the primary reference lot. For lot acceptance, the loss on drying after 2 h at 105 °C is controlled at ≤5.0%; the residue retained on a 25 μm polyamide sieve after hot-water dispersion is controlled at ≤0.2%; and the pH of a 1% aqueous extract is held between 6.5 and 8.5. The visible absorbance maximum in demineralized water of conductivity <1 μS/cm falls between 520 nm and 560 nm, and strength calculations are made at that maximum on a double-beam spectrophotometer with a 1 cm path length. These values are certificate-of-analysis parameters, not application optima.
Prior to exhaust application, Direct Violet N is pre-dissolved at 5–10% concentration in demineralized water heated to 80–90 °C, then filtered through a 100 μm stainless steel wire mesh before entering the dosing tank. Cold-water paste preparation below 50 °C produces incomplete dispersion and increases the risk of specks on jig-dyed cotton. The prepared stock solution remains pourable for 4–6 h at 60 °C; after that interval, a slight viscosity increase is observed without full precipitation. In hard water above 150 mg/L CaCO₃, the solution stability is maintained by addition of 1–2 g/L polyphosphate sequestrant before dye addition.
In a 400 kg soft-flow jet machine dyeing cotton knit goods at a liquor ratio of 1:10, the pre-dissolved Direct Violet N is added at 40 °C; electrolyte is introduced as 5–20 g/L sodium sulfate or 2–8 g/L sodium chloride. The bath is then ramped at 1.5 °C/min to 95–98 °C and held for 30–45 min. Bath exhaustion for a 2.0% on-mass-of-fibre shade is typically found in the 70–85% interval before cationic fixative aftertreatment. At sodium chloride additions below 3 g/L, exhaustion falls by more than 15 percentage points; above 15 g/L NaCl at 95 °C, the dye aggregation number increases and unlevel uptake becomes measurable on package columns with liquor outflow below 0.8 m/s. Published data for the exact aggregation constant of this dye is limited; the salt response is consistent with direct disazo dye behavior.
The highest strike rate is observed in the 80–95 °C interval, which makes controlled ramping more important than prolonged hold time. In hank-dyeing machines with external liquor circulation of 2.0–3.0 bath turnovers per minute, package density is limited to 0.35–0.40 g/cm³; higher density induces filtration of aggregated dye at the inlet face and shade variation between inner and outer layers. Shade reproducibility is further improved by split electrolyte addition: 60% at 70 °C and 40% at 90 °C reduces initial strike by 10–15% relative to single-stage addition. In open-width jig dyeing, where migration time is shorter, the full electrolyte dose is added only after levelling is confirmed at 85 °C; otherwise centre-to-selvedge variation can exceed 0.5 ΔEcmc under D65/10° illumination.
In continuous pad-dry processing for woven cotton, Direct Violet N is applied from a pad trough at 20–40 °C with a nip expression of 70–80%. The padded fabric is dried in a multi-zone stenter with the first zone not exceeding 120 °C to limit migration; first-zone temperatures above 140 °C cause dye migration to the fabric surface and reduce rub fastness before the fixation bath. Rub fastness is then assessed by ISO 105-X12:2016. For paper and leather stock, the product is more often added directly to the beater or wet-end stock at 0.1–1.5% on dry furnish; the anionic charge of the dye requires retention aid adjustment when the furnish contains high levels of cationic polyacrylamide.
Direct Violet N is an anionic disazo dye; it binds to cellulosic substrates by hydrogen bonding and van der Waals aggregation rather than by covalent reaction. This distinction from C.I. Reactive Violet 5 is operationally significant: reactive staining requires alkali and 60–80 °C fixation and produces a wash-fast covalent attachment, whereas Direct Violet N requires no alkali and exhausts at 95–98 °C but yields untreated wash fastness of only 2–3 on the ISO 105-C06:C2 grey scale. Compared with C.I. Basic Violet 1, a cationic triphenylmethane dye, Direct Violet N has no affinity for acrylic fibre under normal exhaust conditions and must not be combined with cationic fixatives in the same bath because of immediate coacervation and filter blockage.
Within the direct violet category, Direct Violet N is not aftercoppered. Products with copper-complex structures show better light fastness by 1–2 blue wool units and better wet fastness, but introduce metal effluent load and shade dulling. Direct Violet N is therefore selected when higher chroma violet mass tone is prioritized over maximum fastness. The absence of coordinated metal also simplifies wastewater compliance under typical municipal discharge permits, although the sulfonated disazo structure still contributes to colour load in spent baths.
Because the disazo structure contains sulfonate groups, process water hardness above 150 mg/L CaCO₃ creates calcium-dye complexes that reduce solubility and shade reproducibility. Aminopolycarboxylate sequestrants may dissolve traces of iron from unlined steel dyeing vessels and shift shade toward a duller blue-red. The dye is incompatible with strong reducing agents; sodium hydrosulfite at concentrations above 1 g/L causes irreversible reductive cleavage and loss of chroma. Alkaline conditions above pH 9.0 accelerate desorption from cellulose and should be avoided in prolonged wet processing.
| Parameter | Method / instrument | Acceptance band |
|---|---|---|
| Tinctorial strength | Absorbance ratio at λmax vs primary standard, 1 cm quartz cell | 100% ± 3% |
| Loss on drying | ISO 787-2:1981, 105 °C | ≤5.0% |
| Water-insoluble residue | 25 μm sieve, hot water extraction | ≤0.2% |
| pH of 1% extract | ISO 787-4:1981 | 6.5–8.5 |
| Reductive amine release | EN 14362-1:2012 | Below 30 mg/kg |
Untreated dyeings have high water solubility, so warm-water contact removes loosely bound dye. The standard aftertreatment uses a cationic dicyandiamide-formaldehyde fixative at 2–6% on weight of fibre in a fresh bath at 40–50 °C for 20 min. This raises washing fastness by 1–1.5 grey-scale units under ISO 105-C06 but reduces light fastness by 0.5–1.0 blue wool units under ISO 105-B02. Overdosing beyond 6% on weight of fibre stiffens the hand and produces a duller violet due to surface precipitation. The product is typically packed in 25 kg fibre drums with polyethylene liners and stored at 5–35 °C; dusting during weigh-up is controlled by local exhaust ventilation with a capture velocity of 0.5 m/s at the transfer point.
