Description

Direct Blue 71 CAS NO 4399-55-7 is a synthetic, water-soluble anionic dye belonging to the class of direct dyes. It is valued for its strong affinity to cellulosic fibers, providing deep, vibrant blue shades with good wash fastness. This dye is essential for manufacturers in the textile, paper, and leather industries seeking consistent, high-quality coloration for their products.

Application

• Textile Dyeing: Primary application for dyeing cotton, rayon, linen, and other cellulosic fibers.
• Paper Coloring: Used in the production of colored papers, tissues, and paperboard.
• Leather Finishing: Imparts color to leather goods in the tanning industry.
• Ink Formulation: A component in the manufacture of certain types of inks and toners.
• Biological Staining: Employed as a histological stain in laboratory settings.
• Wood Staining: Used for coloring wood and wood-based products.

Basic Information

Product Name	Direct Blue 71
CAS No.	4399-55-7
Molecular Formula	C₄₀H₂₃N₇O₁₃S₄·4Na
Molecular Weight	1029.86 g/mol (for tetrasodium salt)
Synonyms	Direct Blue 71; C.I. 34140; Direct Blue 71 (C.I. 34140); Pontamine Blue 4B; Direct Blue 4B; Direct Blue B; Amanil Sky Blue 6B; Atlantic Blue 2B; Benzo Sky Blue; Sirius Supra Blue BRR
EINECS	224-528-8

Quality Control

Our Direct Blue 71 is manufactured under a strict quality management system to ensure batch-to-batch consistency and performance. Each lot is tested against key parameters including color strength, shade, solubility, and impurity profile. A Certificate of Analysis (COA) detailing these results is provided with every shipment to guarantee compliance with your specifications.

Storage

Preserve in a tightly closed container, protected from light. Store in a cool, dry, and well-ventilated area at room temperature (15-25°C). Keep away from strong oxidizing agents.

Specification

Item	Specification
Appearance	Dark blue to bluish-black powder
Identification (IR)	Conforms to standard
Color Strength	100 ± 3% (vs. Standard)
Moisture Content	≤ 5.0%
Water Insoluble Matter	≤ 1.0%
Shade	Conforms to standard
Solubility in Water	Complete

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.