Acid Black 2 (CAS 8005-03-6), also widely known as Nigrosine Water Soluble or C.I. 50420, is a black synthetic dye belonging to the phenazine class. It typically appears as shiny black granules or a fine black powder. Unlike its solvent-soluble counterpart, Acid Black 2 is highly soluble in water, forming a beautiful bluish-black solution. It is the gold standard for black inks and premium leather dyeing due to its deep tone and reliable chemical properties.

1. Feature: Superior Water Solubility

• Advantage: Dissolves rapidly and completely in water without leaving sediment or undissolved particles.

• Benefit: Process Efficiency: Prevents clogging in fountain pens and industrial sprayers, reducing equipment maintenance and downtime.

2. Feature: Intense Tinting Strength & Bluish-Black Shade

• Advantage: Provides a deep, rich black color with a classic bluish undertone even at low concentrations.

• Benefit: Cost-Effective Coloring: Achieves high-end aesthetic results using less dye, lowering the overall cost per unit of your finished product.

3. Feature: Excellent pH Stability

• Advantage: Maintains consistent color performance across a wide range of acidic and mildly alkaline conditions.

• Benefit: Product Consistency: Ensures your leather or ink products maintain their color integrity during different stages of manufacturing and storage.

4. Feature: Low Salt & Impurity Content

• Advantage: Strictly controlled manufacturing process ensures minimal inorganic salt and heavy metal residues.

• Benefit: Safe & High Quality: Ideal for sensitive applications like biological staining and specialized stationery, meeting international quality standards.

Stationery & Inks

The primary choice for manufacturing fountain pen inks, stamp pad inks, and marker inks where high solubility and flow are required.

Leather Industry

Used extensively for dyeing high-quality leather goods, providing deep penetration and a sophisticated bluish-black finish.

Wood & Paper Staining

Utilized in wood stains and paper coloring to achieve uniform, light-fast black shades.

Biological Staining

Used as a negative stain in microbiology and laboratory research for visualizing cells and background contrast.

• Packaging: 25kg fiber drums with PE inner lining; customized packaging available for bulk orders.

• Storage: Store in a cool, dry, and well-ventilated area. Keep containers tightly closed to prevent moisture absorption (hygroscopic). Keep away from strong oxidizing agents and direct sunlight.

Nigrosine Water Soluble; Nigrosine WS; C.I. Acid Black 2; C.I. 50420; Nigrosine B; Water Soluble Black.

1. Q: What is the difference between Acid Black 2 and Solvent Black 5?

   A: Acid Black 2 is water-soluble (used for aqueous inks/leather), while Solvent Black 5 (Spirit Nigrosine) is alcohol/solvent soluble (用于油漆/塑料).

2. Q: Does this dye cause clogging in fountain pens?

   A: No. Our premium grade is triple-filtered to ensure insoluble matter is < 0.5%, making it perfectly safe for high-end stationery.

3. Q: How can I achieve a "Neutral Black" instead of "Bluish Black"?

   A: You can blend Acid Black 2 with small amounts of Acid Orange or Acid Yellow to neutralize the blue undertone.

4. Q: Is Acid Black 2 light-fast?

   A: It has moderate to good light-fastness (Rating 4-5). It is suitable for indoor applications like leather and stationery but not recommended for long-term outdoor exposure.

5. Q: Can I use this for biological staining?

   A: Yes, our high-purity powder is suitable for laboratory use as a negative stain for bacteria.

6. Q: Is the granular form better than the powder form?

   A: Granules are preferred for industrial use because they generate less dust, making the workshop cleaner and safer for workers.

7. Q: Is your Acid Black 2 compliant with REACH?

   A: Yes, we provide full REACH compliance and MSDS documentation for our European and North American clients.

8. Q: What is the maximum concentration possible in water?

   A: At room temperature, you can achieve about 5-8% concentration. Heating slightly can increase solubility for concentrated masterbatches.

9. Q: Does it stain skin or clothes permanently?

   A: As a strong dye, it will stain. However, being water-soluble, it can usually be washed off skin with soap and water, though it is very persistent on porous materials.

10. Q: Can you provide customized concentrations (e.g., 150% or 200%)?

    A: Yes, we offer standard strength (100%) and high-strength versions depending on your specific formulation needs.