water-soluble cationic basic dye Basic black
Product Introduction
Basic black, also named cationic black, is a water-soluble cationic basic dye. Its molecule contains alkaline amino groups. After dissolving in water, it ionizes into positively charged dye cations, which bind to negatively charged substrates via electrostatic adsorption for coloration. Commercial basic black products are either single-component dyes or blends of basic blue, basic yellow and basic red to formulate pure black shade.
Physical & Chemical Properties
Appearance: dark black / bluish-black fine powder
Water solubility: highly soluble in cold and hot water, solubility range: 150~300 g/L, aqueous solution shows black color
Optimal pH for dyeing: weakly acidic pH 4.5~6.0; color shade becomes lighter and dye uptake declines under alkaline conditions
Fastness performance: extremely high tinctorial strength and fast dyeing speed; light fastness: Grade 4–6, moderate washing & soaping fastness (Grade 3–4). Wet fastness can be improved by applying cationic fixing agent; not resistant to chlorine bleaching.
Dyeing Mechanism
Substrates such as pulp, leather and acrylic fiber carry negatively charged groups (carboxyl, sulfonic groups) on their surface. Cationic dye molecules firmly attach to substrates through ionic bond electrostatic adsorption. Due to fast exhaustion rate, uneven dyeing is likely to occur; retarding agent is required for acrylic dyeing to control dyeing speed and ensure levelness.
Main Application Fields
Paper Industry (Largest Consumption Field)
Internal dyeing for colored cardboard, incense paper, seed coating paper, decorative paper, filter paper and black toilet paper, featuring low dosage, uniform coloration and cost-effectiveness.
Leather Dyeing
Through-dyeing for shoe upper leather, glove leather and artificial leather after tanning, with excellent penetration and deeper black shade at lower cost compared with acid black dyes.
Textile Printing & Dyeing
Primary application: exclusive black dye for acrylic fiber (polyacrylonitrile fiber)
Applicable substrates: silk and wool; pre-mordanting treatment is required for cotton and linen, otherwise poor fastness will occur with direct dyeing.
Other Uses
Water-based ink, writing ink, educational dyes, wood coloring and biological tissue staining.
Advantages & Disadvantages
Advantages
Ultra-high tinctorial strength, deep black shade achieved with small dosage, economical cost
Easy dissolution in cold water, simple operation, compatible with high-speed continuous production lines
Strong affinity to anionic substrates, high dye exhaustion efficiency
Disadvantages
Conventional grades have ordinary washing fastness, fixing treatment is mandatory
Cannot dye unmodified cotton directly
Slight fading may happen under long-term sunlight exposure
Storage, Transportation & Safety Notes
Storage: Keep sealed in cool and dry warehouse, moisture-proof; do not store together with anionic dyes (flocculation and precipitation will cause dye failure)
Personal protection: Dye dust may irritate respiratory tract; wear dust mask and protective gloves during operation
Compliance: Meet REACH, ZDHC and banned azo dye test requirements for export shipments
