Description

Direct Red 13 is a synthetic azo dye belonging to the direct dye class, known for its affinity for cellulosic fibers like cotton and paper. Its primary value lies in providing a strong, substantive red color with good wash fastness properties without the need for a mordant. This product is essential for manufacturers in the textile, paper, and leather industries seeking efficient and cost-effective dyeing solutions. We supply high-purity Direct Red 13 CAS NO 1937-35-5 to meet the stringent quality demands of global industrial applications.

Application

• Primary dyeing and tinting of cotton, viscose, and other cellulosic textiles.
• Coloration of paper products, including specialty papers and packaging materials.
• Dyeing of leather for footwear, apparel, and upholstery.
• As a colorant for wood staining and related products.
• Used in the manufacture of inks for specific printing applications.
• Potential use as a biological stain in laboratory settings (subject to grade suitability).

Basic Information

Product Name	Direct Red 13
CAS No.	1937-35-5
Molecular Formula	C32H21N7Na2O11S2
Molecular Weight	781.66 g/mol
Synonyms	Direct Red 13; Congo Red 4B; C.I. Direct Red 13; Direct Red 4B; Direct Red C; Pontamine Red 4B; Aizen Direct Red 4BH; Atul Direct Red 4B; Benzo Fast Red 4BL; Chlorazol Fast Red 4B; Diazol Red 4B; Sirius Red 4B
EINECS	217-710-7

Quality Control

Our production of Direct Red 13 adheres to strict quality management protocols 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 technical specifications and industry standards.

Storage

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

Specification

Item	Specification
Appearance	Reddish-brown powder
Identification (IR)	Conforms to standard
Assay (HPLC)	Min. 95%
Color Strength	100 ± 3% (vs. Standard)
Moisture Content	Max. 5.0%
Water Solubility	Conforms
pH (1% Solution)	6.0 - 8.0
Ash Content	Max. 1.0%

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