Description

C.I.Acid Red 256 is a synthetic organic dye belonging to the azo chemical class, identified by CAS No. 12238-49-2. It is valued for its strong, vibrant red color and good fastness properties, making it a critical component for achieving consistent and durable coloration. This acid dye is primarily utilized by manufacturers in the textile, leather, and paper industries for dyeing protein-based fibers like wool, silk, and nylon.

Application

• Textile Dyeing: Primary application for dyeing wool, silk, and polyamide (nylon) fibers to achieve bright red shades.
• Leather Finishing: Used in the coloration of leather goods, providing rich color with good penetration and lightfastness.
• Paper Staining: Employed for coloring specialty papers, including decorative and packaging materials.
• Ink Formulation: A colorant component in the manufacture of certain inks for industrial or specialty printing.
• Biological Staining (Histology): Potential use as a stain in microscopic analysis for biological tissues in laboratory settings.
• Wood Staining: Applied for tinting and enhancing the appearance of wood products.

Basic Information

Item	Detail
Product Name	C.I. Acid Red 256
CAS No.	12238-49-2
Molecular Formula	C20H13N4NaO4S
Molecular Weight	452.40 g/mol
Synonyms	Acid Red 256; C.I. 16255; 2-Naphthalenesulfonic acid, 7-[(2,4-dinitrophenyl)azo]-8-hydroxy-, monosodium salt; Mordant Red 19; Sodium 7-[(2,4-dinitrophenyl)azo]-8-hydroxynaphthalene-2-sulfonate; Acid Leather Red BG; Acid Leather Red B; Acid Fast Red A
EINECS	235-447-5

Quality Control

Our production of C.I. Acid Red 256 adheres to stringent quality management protocols to ensure batch-to-batch consistency and performance reliability. Each lot is analyzed for critical parameters including color strength, shade, solubility, and impurity profile. Certificates of Analysis (COA) documenting purity, physical properties, and conformance to agreed specifications are provided with every shipment.

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 and incompatible materials.

Specification

Item	Specification
Appearance	Red to dark red powder
Identification (IR)	Conforms to standard
Color Strength	100 ± 3% (vs. Standard)
Moisture Content	≤ 5.0%
Water Solubility	Conforms
Ash Content	≤ 1.0%
pH (1% Solution)	6.0 - 8.0
Heavy Metals (as Pb)	≤ 20 ppm

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