Description

Reactive Black 31 is a high-purity, reactive dye belonging to the vinyl sulfone class, widely recognized for its excellent color fastness and wash-down properties. Its primary value lies in its ability to form strong covalent bonds with cellulosic fibers like cotton and viscose, ensuring vibrant, durable coloration that resists fading. This product is essential for textile manufacturers, dye houses, and chemical distributors serving the global apparel, home furnishing, and industrial fabric markets. Consistent quality and reliable supply are critical for maintaining production efficiency and meeting stringent color standards.

Application

• Textile Dyeing: Primary application for exhaust and continuous dyeing of cellulosic fibers such as cotton, linen, and viscose, producing deep black shades.
• Garment Manufacturing: Used in the production of denim, casual wear, and home textiles requiring high wash and light fastness.
• Industrial Fabrics: Coloration of canvas, tarpaulins, and other heavy-duty fabrics where durability is paramount.
• Yarn Dyeing: Effective for package and hank dyeing processes in the production of colored yarns for weaving and knitting.
• Pad-Batch Dyeing: Suitable for cold pad-batch application methods, offering energy efficiency and high fixation rates.
• Technical Textiles: Potential use in dyeing fibers for automotive interiors and other specialized technical applications.

Basic Information

Product Name	Reactive Black 31
CAS No.	12731-63-4
Molecular Formula	C26H21N5Na4O19S6
Molecular Weight	991.80 g/mol
Synonyms	Reactive Black 31; C.I. Reactive Black 31; Remazol Black B; Vinylsulfone Black B; Levafix Black E-B; Procion Black H-EXL; Dianix Black S-R; C.I. 35155; Tetrasodium 8-[[4-[[4-[(4,6-dichloro-1,3,5-triazin-2-yl)amino]-2-sulfophenyl]azo]-7-sulfonaphthalen-1-yl]azo]-5-hydroxy-1,3,6-naphthalenetrisulfonate
EINECS	Contact for details

Quality Control

Our Reactive Black 31 is manufactured under a strict quality management system to ensure batch-to-batch consistency and performance reliability. Quality is verified through comprehensive testing including spectrophotometric analysis for strength and shade, HPLC for purity, and standardized application tests for fixation and fastness properties. Certificates of Analysis (COA) documenting key parameters are available upon request to support your quality assurance protocols.

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 and excessive heat. Under these conditions, the product remains stable for extended periods.

Specification

Item	Specification
Appearance	Black Powder
Color Strength	≥ 98% (Standard)
Moisture Content	≤ 5.0%
Water Insoluble Matter	≤ 0.5%
pH (1% Solution)	5.5 - 7.5
Fixation Rate	≥ 70% (on cotton)
Fastness to Washing	≥ 4 (ISO 105-C06)
Fastness to Light	≥ 5 (ISO 105-B02)

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