Description

C.I. Acid Red 221 is a synthetic monoazo acid dye valued for its bright red hue and strong affinity for protein fibers like wool, silk, and nylon. Its primary commercial value lies in providing excellent color fastness, particularly to washing and perspiration, making it a reliable choice for demanding textile applications. This dye is essential for manufacturers in the textile, leather, and paper industries seeking vibrant, durable coloration for their products.

Application

• Textile Dyeing: Primary application for dyeing wool, silk, and nylon fibers to achieve bright red shades with good fastness properties.
• Leather Coloring: Used in the dyeing of leather goods, providing rich, uniform color.
• Paper Staining: Employed for coloring specialty papers, including decorative and packaging materials.
• Ink Formulation: A colorant component in the manufacture of certain inks for non-food contact applications.
• Biological Staining: Potential use as a histological stain in laboratory settings (specific grades required).

Basic Information

Item	Detail
Product Name	C.I. Acid Red 221
CAS No.	63641-89-4
Molecular Formula	C22H14N4Na2O7S2
Molecular Weight	556.48 g/mol
Synonyms	Acid Red 221; C.I. 22120; Acid Leather Red D; Acid Fast Red A; Acid Brilliant Red 3B; Mordant Red 9; 5-[(2,4-Dimethyl-6-sulfophenyl)azo]-6-hydroxy-1-naphthalenesulfonic acid disodium salt; 1-Naphthalenesulfonic acid, 5-[(2,4-dimethyl-6-sulfophenyl)azo]-6-hydroxy-, disodium salt
EINECS	Contact for details

Quality Control

Our C.I. Acid Red 221 is manufactured under a strict quality management system. Every batch undergoes comprehensive analytical testing to ensure consistency in strength, shade, and purity. A Certificate of Analysis (COA) detailing parameters such as assay, solubility, and heavy metal content is provided to guarantee the product meets your specific application requirements.

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 incompatible materials. The product is light-sensitive and should be stored away from direct light exposure to maintain stability.

Specification

Item	Specification
Appearance	Red to dark red powder
Identification (IR)	Conforms to standard
Assay (HPLC)	Min. 95%
Solubility in Water	Conforms
Moisture Content	Max. 5.0%
Ash Content	Max. 1.0%
Heavy Metals (as Pb)	Max. 20 ppm

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