Direct Yellow 27 alias direct light fast yellow 5G, direct bright yellow 5G, direct fast yellow 5G, direct bright yellow L-4G, tin yellow 5G. Appearance is dim yellow uniform powder. Water soluble, slightly sensitive to hard water, Dissolved in water, it is lemon yellow, soluble in cellosolve, slightly soluble in alcohol, slightly oozing in benzene and carbon tetrachloride. It is insoluble in other organic solvents. It is golden yellow in concentrated sulfuric acid. Light, soluble in concentrated nitric acid, a yellowish solution; partially dissolved in concentrated hydrochloric acid to yellow-orange. The aqueous solution with concentrated hydrochloric acid has a golden yellow precipitate, and concentrated sodium hydroxide has a golden orange precipitate. The copper and iron ion color changes.
TRADE NAME:Direct Fast Yellow 5GL,Direct Fast Brilliant Yellow 5G,Direct Fast Brilliant Yellow 5GL,Direct Brilliant Yellow 5GL,Direct Brilliant Yellow L-4G
| Solubility at 90 C | 50g/l |
| Insolubles % | 0.15 |
| Light Fastness | 5 |
| Washing Fatness | 2 |
| Perspiration | 3 |
| Soap Fading | 1-2 |
Solubility(g/L) | SDC classification | displacement(grade) | metal ion effect(grade) | discharge property(grade) | other features | ||
copper | iron | neutral | basic | ||||
50 (97℃) | A | 4~5 | 3~4 | 3~4 | 5 | 5 | — |
sun exposure | soaping | flooding | perspiration | rubbing | ironing | acid and alkali resistant | |||||||
standard depth | 1/12 depth | original color change | white fiber stained | original color change | white fiber stained | original color change | white fiber stained | dry | wet | sulfuric acid | acetic acid | soda ash | |
5 | — | 1 | 1~2 | 2 | 1 | 2~3 | 1 | 5 | — | 5 | 1 | 2~3 | 4~5 |
Direct Yellow 27 Most suitable for dyeing of viscose like cotton, flax, viscose rayon, acetate and jute, also for Ink, Leather and Paper coloration.
Direct Yellow 27 contains a carcinogenic aromatic amine o-aminoanisole, which is a banned dye.
Direct Yellow 27 is optimized for cellulosic materials — 100% cotton and viscose/rayon show the best substantivity and colour yield. For synthetic blends, pre-scouring and the use of leveling agents are recommended to reduce speckling and improve shade uniformity. :contentReference[oaicite:2]{index=2}
Because many direct dyes have only fair washing fastness, improve wet-fastness by (1) after-treatment with a commercial fixing agent (e.g., cationic fixing agents specified for direct dyes), (2) pad-dry-cure methods where compatible, or (3) enzymatic/softener finishing that reduces dye migration. Always validate on lab swatches; fixing protocols vary by textile and dye bath concentration. :contentReference[oaicite:3]{index=3}
Typical exhaustion improves at elevated temperatures — dyebaths approaching 90–97°C (for direct dyeing on cotton/viscose) increase solubility and exhaustion. Salt addition and controlled pH (usually neutral to slightly alkaline depending on TDS) also help. Refer to the manufacturer's TDS for exact dyebath recipes and liquor ratios. :contentReference[oaicite:4]{index=4}
Yes — it is commonly used in printing pastes for cotton and paper. For printing, formulate with suitable thickeners and leveling additives; perform fixation or steaming steps where required by the paste recipe. Color strength and penetration depend on paste viscosity and steaming/fixation schedule. :contentReference[oaicite:5]{index=5}
Direct Yellow 27, like many azo direct dyes, can be persistent in wastewater; industrial effluent should be treated (coagulation/adsorption/advanced oxidation) to meet discharge limits. Follow MSDS/ local regulations for handling, avoid inhalation of dust, and use PPE when weighing/handling powders. For regulatory status or biodegradation data, consult supplier MSDS and local environmental guidance. :contentReference[oaicite:6]{index=6}
