High Strength Direct Red 13
Basic Product Information
Direct Red 13, also named Direct Bordeaux B / Direct Red BE, CAS No.1937-35-5, is a water-soluble disazo direct dye with reddish-brown powder appearance. Its aqueous solution is wine red, and it delivers dark garnet red shade on cotton and viscose fabrics.
It features excellent water solubility (solubility ≥20g/L at 80℃), and achieves optimal dye uptake on cellulosic fibers at 80–100℃ with Glauber’s salt as exhaustion agent. It has light fastness Grade 4–5, dry rubbing fastness Grade 4 and wet rubbing fastness Grade 3, while its washing fastness is moderate; cationic fixing agent is recommended for dark shades to improve wet fastness.
It is widely applied in dyeing and direct printing of cotton, viscose, silk, polyamide and viscose-polyamide blended textiles, also suitable for pulp coloring and water-based leather tinting.
Core Physical & Chemical Properties
1. Solubility
● Water solubility: Easily soluble in hot water, slightly soluble in cold water; aqueous solution presents bluish red. Optimum dissolving temperature 30–70℃, suitable for neutral to weak alkaline water (pH 7–9).
● Organic solvent: Soluble in ethanol to produce pink solution; micro-soluble in acetone; insoluble in benzene, chloroform and other non-polar solvents.
2. Acid & Alkali Color Reaction
● Concentrated sulfuric acid: Dark blue solution, turns red after dilution
● Concentrated hydrochloric acid: Separate purplish red precipitate
● Caustic soda solution: Reddish orange liquid, color slightly dulled under strong alkali
● pH adaptability: Stable in pH 6–10; obvious color shift under strong acid
3. Metal Ion Stability
● Slightly dark shade when meeting copper ions; little color change with iron ions
● Medium salt tolerance, moderate requirement for water hardness
Application Features
1. Paper Industry
● Scope: Writing paper, packaging cardboard, craft paper toning, forms bright bluish red shade
● Advantages:
✅ Fast dissolution, can be added directly in pulp wet-end, simple operation
✅ Good affinity to cellulose fiber, uniform coloring, stable white water circulation
✅ Low cost, stable batch shade
● Usage dosage: 0.06%–0.5% based on oven-dry pulp; temperature 40–55℃, pH 7–9 recommended
2. Textile Industry
● Applicable fibers: Cotton, linen, viscose, rayon; weak dyeing capacity on silk and wool, invalid for polyester, acrylic
● Dyeing performance: Good leveling property, high color yield, medium migration; add sodium sulfate to improve dye uptake
● Color fastness standard:
Light fastness: Grade 3
Washing fastness: Grade 2–3
Dry rubbing fastness: Grade 4–5
Wet rubbing fastness: Grade 3
3. Other Applications
Light leather dyeing, water-based colorants, waterborne coating toning
Key Technical Index
|
Item |
Index Standard |
|
Color Shade |
Bluish Red |
|
Strength |
100% (Standard Sample) |
|
Moisture Content |
≤5.0% |
|
Water Insoluble Matter |
≤0.15% |
|
Light Fastness |
Grade 3 |
|
Washing Fastness |
Grade 2–3 |
|
Dry Rubbing Fastness |
Grade 4–5 |
|
Wet Rubbing Fastness |
Grade 3 |
|
Package |
25kg kraft bag / fiber drum |
Storage & Transportation
● Storage: Cool, dry, ventilated warehouse, sealed moisture-proof, avoid direct sunlight. Shelf life: 18 months.
● Transportation: General non-dangerous chemical goods; prevent rain and high temperature stacking, separate storage with strong acid and alkali.
