Section
| HS Code | 370426 |
| Product Name | Chrysophenine GX |
| Synonyms | Chrysophenine G; Direct Yellow 12; C.I. Direct Yellow 12 |
| Color Index Name | C.I. Direct Yellow 12 |
| Color Index Number | 24895 |
| Cas Registry Number | 2870-32-8 |
| Chemical Class | Disazo direct dye |
| Molecular Formula | C30H26N4Na2O8S2 |
| Molecular Weight | 680.66 g/mol |
| Appearance | Yellow powder |
| Water Solubility | Soluble in water |
| Dye Type | Direct dye |
| Ionic Character | Anionic |
| Principal Application | Dyeing of cellulose fibers such as cotton and viscose |
| Substantivity | Substantive for cellulose fibers |
As an accredited Chrysophenine GX factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Chrysophenine GX is packaged in 25 kg net polyethylene-lined fiber drums, securely sealed and labeled for chemical handling. |
| Container Loading (20′ FCL) | Chrysophenine GX is packed in 25 kg bags, palletized and shrink-wrapped, then securely loaded into a 20′ FCL dry container. |
| Shipping | Chrysophenine GX (Direct Yellow 12) is typically shipped as a non-hazardous solid dye in sealed, labeled containers at ambient temperature, protected from moisture. Avoid dust and environmental release. Confirm the current SDS and carrier rules; it is generally not regulated as dangerous goods for commercial transport. |
| Storage | Store Chrysophenine GX in a cool, dry, well-ventilated area in a tightly closed container, protected from moisture, direct sunlight, and heat sources. Keep away from strong oxidizing agents and incompatible materials. Prevent dust generation, use appropriate personal protective equipment, and follow local regulations and SDS recommendations. Do not store with food, feed, or drinking water. Ensure secondary containment where required. |
| Shelf Life | Chrysophenine GX is stable for at least 24 months under cool, dry, sealed storage, away from direct sunlight and moisture. |
Exhaust dyeing of cotton poplin and voile starts with a pre-dissolved stock of Chrysophenine GX. The dye is supplied as the disodium salt of C.I. Direct Yellow 12, C.I. 24895, CAS 2870-32-8. The stock solution is prepared at 80–85°C in demineralized water and screened through an 80-mesh stainless steel filter. Dye application for pale to medium yellow shades is 0.1–2.0% o.w.f. at a liquor ratio of 1:10 to 1:20. Sodium chloride is charged in three equal additions at 10 min, 20 min, and 30 min after the bath reaches 85–90°C. Total electrolyte is 10–30 g/L. Dry salt shock causes local dye aggregation and produces shoulder marks on jiggers and overflow machines. Sodium carbonate at 0.5–1.0 g/L buffers the exhaust bath at pH 8.0–9.0. Calcium and magnesium hardness above 10°dH precipitates the sulfonated dye as an insoluble lake; a polyphosphate or polycarboxylate sequestrant is required. Exhaustion continues for 45–60 min. Without cationic aftertreatment, wet fastness remains limited. A dimethylamine-epichlorohydrin fixing agent is applied at 1–3% o.w.f., pH 5.0–6.0, for 20 min at 40–50°C to improve washing performance. The treated substrates are converted into printed dressgoods, pocketing, and lining materials. Fastness claims are assessed by ISO 105-C06:2010, ISO 105-B02:2014, and ISO 105-X12:2016. For REACH Annex XVII entry 43, batch release testing by EN 14362-1:2012 screens for listed aromatic amines below 30 mg/kg. The product is not recommended for fabrics exposed to hypochlorite bleaching; oxidative chlorine fastness is checked by ISO 105-N01:1995 when required.
On continuous pad-steam lines for bleached cotton sheeting, Chrysophenine GX is padded at 8–20 g/L with a wet pickup of 65–75%. Sodium chloride in the pad trough is limited to 5–12 g/L. Above 12 g/L the dye can salt out if trough temperature falls below 20°C. A nonionic wetting agent at 0.3–1.0 g/L is required for uniform fibre wetting. The padder is a two-roll or three-roll unit with controlled deflection rolls. Uneven roll pressure across the working width generates edge mottling. The fabric is passed through an infrared pre-dryer at 90–110°C to reduce moisture to 30–35%. Cylinder drying follows at 110–120°C. Drying above 130°C can cause border-to-centre shade drift and yellow line-defects from fibre migration. Steaming is performed in saturated steam at 101–103°C for 60–120 s. The steamer requires a functioning steam lock and condensation-controlled floor to prevent drop marks on sheeting. In-line pH and conductivity meters control the pad bath; conductivity above 25 mS/cm indicates salt accumulation and requires automatic dilution. The terminal product is bed sheeting and pillowcase fabric. Shade consistency across the working width is monitored by ISO 105-J03:2009; a ΔE CMC 2:1 value above 0.8 is handled as a batch defect. Published data for high-temperature pad-thermofix of this specific dye is limited; a pilot padder trial is required before conversion from pad-steam to pad-dry-cure configuration.
Spun viscose yarn in high-density package machines exhibits core-to-surface shade drift when package density exceeds the flow capacity of the yarn mass. Chrysophenine GX is applied at 0.2–1.5% o.w.f. on perforated stainless steel cones. Package density is maintained at 350–400 g/L. The liquor ratio is 1:8 to 1:12. Sodium chloride at 20–40 g/L is introduced in three aliquots between 15 min and 35 min after reaching 80–85°C. The heating ramp is controlled at 1.5°C/min to avoid unlevel uptake on swollen viscose filaments. Flow reversal cycles alternate 3 min inside-out and 3 min outside-in to reduce differential pressure across the column. Differential pressure above 1.5 bar indicates either excessive package density or fibre swelling; the load is reduced or the reversal interval is shortened. Sodium carbonate at 0.5–1.0 g/L holds pH at 8.0–9.0. Circulation continues for 45–60 min. The bath is cooled to 60°C before shade sampling. Cationic fixative aftertreatment reduces bleed onto adjacent fabrics but can stiffen viscose yarn at high add-on; the dose is held below 2.0% o.w.f. The terminal yarns are embroidery floss, decorative warp yarns, and craft yarns. Wash fastness is assessed by ISO 105-C06:2010 and perspiration fastness by ISO 105-E04:2013. Oeko-Tex Standard 100 certification is product-specific; arylamine release is verified by EN 14362-1:2012 and cannot be inferred solely from dye chemistry.
For bleached kraft and bagasse board, Chrysophenine GX is introduced as a 1–5% aqueous solution at 40–50°C through a dosing pump into the thin stock after centrifugal screening. Pastel board shades use 0.05–0.30% on dry fibre mass. Saturated cover grades use 0.50–1.20%. Thin stock consistency is held at 0.5–1.0%. Process pH is controlled at 5.5–6.5 with alum or sulfuric acid. Above pH 7.0, retention of the anionic dye on bleached kraft decreases sharply. Cationic poly-DADMAC retention aid is dosed separately at 0.2–0.5 kg/t dry fibre at the pressure screen inlet. Pre-mixing the dye with alum liquor above 20 g/L forms a precipitated aluminium lake. The lake causes wire bleeding and press section deposits. Production-scale failure modes include streaking at the slice and shade variation after grade changes. White-water colour rises when the retention aid sequence is interrupted. The terminal products are file folders, tag stock, cover board, and printed paper bags. Coloured paper and board intended for indirect food contact are evaluated under EN 646:2018. Finished board is not specified for exterior exposure because lightfastness under weathering is inadequate. Direct food-contact use is excluded unless migration testing under Regulation (EU) No 10/2011 is completed.
Vegetable-tanned and chrome-free crust leather receives Chrysophenine GX only as a shading component. The dose is 0.2–0.8% of shaved weight for pale yellow shading effects. The drum float is kept at 1:5 to 1:8. The bath is set at 40–50°C. Drum speed is 8–12 rpm. Penetration time is 20–30 min. Formic acid at 0.5–1.0% diluted 1:10 with water is added over 10 min to bring the float to pH 3.8–4.2. Lower pH increases exhaustion but can produce surface bronzing on grain leather. Residual dye in the spent float is visually noticeable above 0.5 g/L; a cationic dye-fixing agent reduces residual colour but may shift the yellow duller. Hard water above 10°dH must be corrected with a polyacrylate sequestrant before dye addition. The finished leather is intended for book covers, stationery leather, and decorative articles. It is not specified for automotive or high-wet-contact footwear components. Colour fastness to rubbing is checked by ISO 11640:2018. Perspiration fastness is checked by ISO 105-E04:2013. Light fastness is checked by ISO 105-B02:2014. Published fastness data specific to Direct Yellow 12 on leather is limited; a pre-production trial with target crust is required to set release limits.
In dye-based flexographic inks for uncoated paper packaging, Chrysophenine GX is used as a liquid dye concentrate at 10–15% dye solids. The finished ink contains 2.0–5.0% dye solids. Dissolution is carried out in a rotor-stator mixer at 40–60°C in deionized water with conductivity below 10 µS/cm. Hard water reduces solubility and creates filter-blocking precipitates. The pH is adjusted with monoethanolamine to 8.0–9.5. The dye solution is passed through a 5 µm absolute polypropylene bag filter before letdown. The finished ink is filtered again through a 5 µm cartridge before filling into drums or pails. Cationic acrylic emulsions are incompatible with the anionic dye; mixing causes coagulation that blocks anilox cells in CI flexo presses. Finished viscosity is adjusted to 22–28 s on a Zahn cup #2 at 25°C for corrugated preprint units. Brookfield viscosity at 25°C is typically 100–300 mPa·s. The terminal printed products are paper sacks, corrugated preprint, and gift wrap. Lightfastness of printed matter is assessed by ISO 12040:2013. For materials intended for indirect food packaging, compliance with Regulation (EU) No 1935/2004 is required. The dye is not suitable for direct food-contact inks. Each production lot is checked for pH, filter blocking tendency, and spectral strength by UV-Vis at the maximum absorbance of the yellow chromophore.
Competitive Chrysophenine GX prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615365186327 or mail to sales3@liwei-chem.com.
We will respond to you as soon as possible.
Tel: +8615365186327
Email: sales3@liwei-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Chrysophenine GX is a standardised commercial form of the anionic disazo stilbene direct dye C.I. Direct Yellow 12, C.I. 24895, CAS 2870-32-8. The molecule is a disodium salt with formula C30H26N4Na2O8S2 and molar mass 680.66 g/mol. In dilute aqueous solution the principal absorption maximum falls between 405 nm and 415 nm, yielding a green-shade yellow with high tinctorial strength. The dye is water-soluble and substantive to cellulosic fibres in the presence of electrolyte; it is used in exhaust dyeing of cotton, viscose, linen, jute, paper stock, and selected leather drum dyeing. Unlike reactive yellow chromophores, it does not form a covalent bond with cellulose; wet fastness under ISO 105-C06 is therefore lower unless a cationic aftertreatment is applied. The GX grade designation is supplier-specific, and the controlling technical identity is spectrophotometric conformity to C.I. Direct Yellow 12.
Production-scale exhaust dyeing of cotton knitted fabric on a soft-flow machine with a liquor ratio of 1:8 and fabric running speed of 180–220 m/min is typically started at 40 °C with 0.5–1.0 g/L wetting agent. The dyebath is raised to 85–95 °C at 1–2 °C/min. Sodium sulfate is preferred over sodium chloride in stainless-steel machines above 80 °C because chloride contributes to pitting corrosion. The salt is split into two portions: 50% at 60 °C before dye addition and 50% after 20 min at top temperature. Exhaustion is monitored by absorbance at 410 nm; pale depths below 0.5% owf typically exhaust above 85%, whereas heavy depths above 1.5% owf can leave 10–20% residual dye in the bath.
In jig dyeing of cotton poplin at 120 g/m², the high substantivity of C.I. Direct Yellow 12 requires staged salt addition to prevent end-to-end shade variation. Machines operating below 30 m/min with low liquor turbulence produce unlevel uptake in the first ends; adding salt in 3 equal portions over 15 min after dye distribution is a standard corrective action. Continuous pad application on cotton woven fabric uses a padder with nip pressure 2–3 bar and pickup 70–80%. The padding liquor contains 0.5–1.0 g/L wetting agent, 5–10 g/L sodium sulfate, and a migration inhibitor. Fabric speed of 40–60 m/min and drying cylinder temperatures limited to 110–120 °C for 20–30 s reduce migration. A subsequent acid sour at pH 4.5–5.0 improves wash-down and removes unfixed dye before drying.
For viscose rayon, the temperature is lowered to 70–80 °C because regenerated cellulose swells more rapidly and dyes more evenly at lower strike rates. Without aftertreatment, typical cotton dyeings at 1/1 standard depth show washing fastness 2–3 under ISO 105-C06 A1S, light fastness 3 under ISO 105-B02, and wet rubbing fastness 2–3 under ISO 105-X12. Cationic fixative aftertreatment at 40–50 °C and pH 5.0–6.0 raises washing fastness to 3–4 but can reduce light fastness by 0.5–1.0 blue wool units.
Commercial dye powders are standardized by strength; a typical acceptance window for Chrysophenine GX is 95–105% relative to a C.I. Direct Yellow 12 reference by UV-Vis spectrophotometric assay at the absorption maximum. Moisture above 5.0% can reduce storage stability and cause clumping in automatic dispensing systems; powder feed hoppers on continuous dye ranges should be equipped with vibratory feeders and moisture-resistant seals when ambient relative humidity exceeds 60%. The dry powder is best stored below 40 °C in sealed HDPE containers.
| Parameter | Value or range | Reference method or basis |
|---|---|---|
| C.I. generic name | C.I. Direct Yellow 12 | Colour Index |
| C.I. constitution number | 24895 | Colour Index |
| CAS registry number | 2870-32-8 | CAS |
| Molar mass | 680.66 g/mol | Calculated from molecular formula |
| Principal absorption maximum | 405–415 nm | UV-Vis spectrophotometer, 10 mm quartz cuvette, deionised water |
| pH of 1% aqueous slurry | 7.0–9.0 | pH electrode at 25 °C |
| Moisture | ≤ 5.0% | Gravimetric drying at 105 °C |
| Water-insoluble matter | ≤ 0.5% | Filtration through 45 µm screen |
| Strength versus C.I. Direct Yellow 12 reference | 95–105% | UV-Vis spectrophotometric assay |
The values are representative acceptance windows used in commercial dye standardization; the batch certificate of analysis is the controlling document for a specific lot. Published data for this specific grade may vary by manufacturer and is best confirmed through the supplier’s certificate.
In dyehouses where supply water total hardness exceeds 150 mg/L CaCO3, unlevel dyeings of C.I. Direct Yellow 12 are more frequent because the sulfonate groups interact with divalent cations to form aggregates with reduced solubility. Batch logs from cotton package dyeing show differential pressure increases across yarn packages when calcium-dye complexes form at 95 °C; package density should be maintained at 350–400 g/L and flow reversal set to 4 min intervals to limit channelling. The dyebath should be softened to below 30 mg/L CaCO3 or sequestered with 1–2 g/L tetrasodium EDTA or 0.5–1.0 g/L polyphosphonate. Polyvalent cations also depress solubility in continuous pad troughs, causing tailing; padder speed 40–60 m/min and replenishment flow of 0.5–1.0 L/min maintain concentration balance.
Do not combine Chrysophenine GX with cationic fixatives in the same dyebath. The anionic dye and cationic polymer form insoluble complexes that precipitate and cause spotting. Aftertreatment is carried out as a separate exhaust step at 40–50 °C and pH 5.0–6.0, using 1–3% cationic fixing agent on weight of fabric. Residual anionic auxiliary matter from dyeing can consume the fixative; a cold rinse and optional acid sour at pH 6.0 before fixation improve reproducibility. Avoid combination with amine-based additives that may alter the zeta potential of the dye anion and reduce exhaustion.
For paper stock dyeing of bleached kraft pulp, anionic C.I. Direct Yellow 12 shows low retention without cationic drainage. On a fourdrinier machine producing 80 g/m² copy paper at 800 m/min, addition of 0.02–0.05% poly-DADMAC on dry pulp at the thick-stock pump has been observed to raise first-pass retention above 90%; without retention aid, tinted white water can contain more than 30% of added dye. Alum at 1–3% dry pulp and pH 4.5–5.5 also improves retention but can shift the yellow shade slightly red. The dye is added as a 1–2% stock solution through a mass flow meter; high shear after addition should be minimized because shear-induced flocculation of cationic-dye complexes can cause motiling. Anionic trash in mechanical pulp or coated broke increases cationic demand; charge demand should be measured on-line with a streaming current detector before setting retention aid dosage. Published data for this specific configuration is limited when the furnish contains high levels of anionic coated broke; laboratory retention trials using a dynamic drainage jar are required to set dosage.
Chrome-tanned leather drum dyeing with Chrysophenine GX is performed at 55–60 °C and pH 4.5–5.0 in a 150–200% float. The dye penetrates retanned leather slowly; drum speed of 8–12 rpm for 30–45 min followed by formic acid fixation at pH 3.8–4.0 yields level shades. C.I. Direct Yellow 12 has stronger affinity for retanned collagen surfaces than acid dyes of similar hue and can build to deep shades with 1.5–2.5% dye on shaved weight. Pale shades below 0.5% require double addition and extended drum time to avoid grain pattern emphasis. At pH below 3.8, the dye may precipitate on the grain surface and cause bronzing; at pH above 5.0, exhaustion is incomplete and the spent float remains strongly coloured. A retanning step before dyeing with 3–5% synthetic retanning agent improves levelness and depth.
Chrysophenine GX should be selected over reactive yellow dyes only when process simplicity and shade brightness outweigh wet fastness. Reactive dyes such as C.I. Reactive Yellow 145 require alkaline fixation at pH 10.5–11.5 and 60–80 °C, followed by hot and cold rinses to remove hydrolyzed dye. Direct Yellow 12 exhausts at 85–95 °C without alkali and requires only a cold rinse; the dyeing cycle is shorter by 30–60 min. Against pigment yellow systems, the direct dye produces transparent dyeings without binder and does not affect fabric handle, but wet rubbing fastness is lower because no binder film is present. Against sulfur dyes, Chrysophenine GX avoids sodium sulfide or reducing sugars, but sulfur dyes show superior washing fastness after oxidation.
| Feature | Chrysophenine GX / C.I. Direct Yellow 12 | Reactive Yellow 145 | Pigment Yellow 12 |
|---|---|---|---|
| Water solubility | Water-soluble anionic | Water-soluble anionic | Water-insoluble dispersion |
| Fixation mechanism | Hydrogen bonding and substantivity | Covalent bond to cellulose under alkali | Binder film at 120–150 °C |
| Application temperature | 85–95 °C | 60–80 °C | Binder cure |
| Washing fastness, ISO 105-C06 A1S | 2–3 without fixative; 3–4 with cationic fixative | 4–5 | 4–5 with binder |
| Light fastness, ISO 105-B02 | 3 at 1/1 standard depth | 5–6 at 1/1 standard depth | 6–7 full shade |
| Process cycle | Exhaust, cold rinse, optional fix | Exhaust, alkali, multi-rinse | Pad, dry, cure |
| Handle | Soft | Soft | Firmer, binder-dependent |
| Effluent colour | Moderate unfixed dye | High hydrolyzed reactive | Low water-phase colour |
Regulatory screening for azo colorants is performed according to EN ISO 14362-1:2017; C.I. Direct Yellow 12 is not classified in Annex XVII entry 43 of REACH for restricted aromatic amines, but mill laboratories should verify each batch because reduction cleavage products can vary with formulation intermediates.
Chrysophenine GX powder generates dust during manual weighing; local exhaust ventilation and dust-tight transfer systems are required. Operators should use EN 149 FFP2 respirators and nitrile gloves. Aqueous discharges containing unfixed C.I. Direct Yellow 12 should not be released to surface water without site permit; colour removal before discharge is achieved by coagulation–flocculation at pH 5.0–6.0 with ferric chloride at 200–500 mg/L. Anaerobic biological treatment removes azo dyes by reductive cleavage, but colour removal efficiency varies with sludge retention time and temperature.
