Acid Black 2 appearance is black with glittering particles. It is soluble in water and blue-violet, soluble in ethanol and blue. The dye is blue in concentrated sulfuric acid, and it is purple after dilution and forms a precipitate. The aqueous solution plus sodium hydroxide has a dark purple precipitate.
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It mainly used for dyeing leather. It is also suitable for dyeing paper, wood, soap, anodized aluminum, wool, silk, and also for making ink.
| ITEM | STANDARD | RESULT |
| Appearance | Black crystal | Black |
| Moisture | 6% max | 4.50% |
| Ash Content | 17% max | 15.10% |
| Strength | 100% | 108% |
Test Methods | fiber | Alkali shrinkage | Acid shrinkage | Seawater discoloration | Soaping discoloration | Sun exposure |
ISO | silk | 3 | 4 | 4 | 4 | 5 |
Acid Black 2 is an anionic dye that binds primarily by electrostatic attraction to positively charged (protonated) amino groups on protein fibers (wool, silk) and on nylon. Hydrogen bonding and van-der-Waals forces provide additional fixation; the process is run under mildly to strongly acidic conditions to maximize ionic attraction.
Acid Black 2 gives deep black shades with good wet fastness on protein fibers and nylon, but overall lightfastness and rubbing fastness depend on shade depth and substrate; some formulations use blends or milling classes to improve fastness. For outdoor/exterior permanence or top-grade lightfastness, consider testing alternative blacks or mixture strategies.
Store in a cool, dry, well-ventilated area in tightly closed containers. Avoid contact with strong oxidizers. Use appropriate PPE (gloves, goggles, dust mask for powders); for fine powders control dust to reduce inhalation and combustible dust hazards. Refer to the supplier MSDS for exact safety data.
