Description

C.I. Acid Yellow 129 is a synthetic monoazo acid dye widely recognized for its bright, greenish-yellow hue and excellent fastness properties. This high-performance dye is engineered to deliver consistent, vibrant coloration with strong affinity for protein-based fibers like wool, silk, and nylon. It is a critical component for manufacturers in the textile, leather, and paper industries seeking reliable and wash-fast yellow shades. Our supply of C.I. Acid Yellow 129 CAS NO 12220-77-8 ensures batch-to-batch consistency for your most demanding dyeing applications.

Application

• Textile Dyeing: Primary application for dyeing wool, silk, and nylon fibers and fabrics.
• Leather Finishing: Used for coloring leather goods, providing rich and even coloration.
• Paper Staining: Imparts a bright yellow color to specialty papers and paper products.
• Ink Formulation: A colorant for inks where acid dye compatibility is required.
• Biomedical Staining: Potential use as a biological stain in laboratory settings.
• Polyamide Dyeing: Effective for coloring various polyamide materials beyond traditional textiles.

Basic Information

Product Name	C.I. Acid Yellow 129
CAS No.	12220-77-8
Molecular Formula	C16H12N4Na2O7S2
Molecular Weight	478.40 g/mol
Synonyms	Acid Yellow 129; Acid Leather Yellow G; C.I. 19166; Acid Fast Yellow G; Lanasyn Yellow G; Supranol Yellow GW; Telon Yellow G; Acid Yellow G; 2,7-Naphthalenedisulfonic acid, 5-[(4-aminophenyl)azo]-3-[[4-[(2,4-diaminophenyl)azo]phenyl]azo]-4-hydroxy-, sodium salt (1:2)
EINECS	Contact for details

Quality Control

Every batch of C.I. Acid Yellow 129 is manufactured and tested under a strict quality management system to ensure it meets the high standards required for industrial dyeing. Our quality control protocol includes verification of color strength, shade, solubility, and fastness properties. A comprehensive Certificate of Analysis (COA) detailing purity, physical parameters, and performance characteristics is provided with each shipment to guarantee traceability and compliance.

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. The container must be kept tightly closed to prevent moisture absorption and contamination.

Specification

Item	Specification
Appearance	Yellow to orange powder
Identification (IR)	Conforms to standard
Assay (HPLC)	Min. 95%
Color Strength	100 ± 3%
Shade	Within agreed tolerance
Moisture Content	Max. 5.0%
Water Solubility	Conforms
Ash Content	Max. 1.0%

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