High-Quality Direct Red 243

Product Name: Direct Red 243, Direct Lightfast Red BWS

English Name: Direct Red 243

C.I. No.: 29165

CAS No.: 6507-79-5

Molecular Formula: C₃₈H₂₄N₆Na₄O₁₆S₄

Molecular Weight: 1072.81

Appearance: Uniform reddish-brown powder

Direct Red 243 is a medium-to-high grade direct dye with the following key properties:

● Excellent light fastness

● Pure shade: bright blueish-red, full and stable color

● High exhaustion rate, good affinity for cellulosic fibers

● Good leveling property, not easy to dye unevenly

● Stable acid and alkali resistance, wide application range

● Strength: Standard 100%, 200%

● Good solubility, fast and full dissolution in hot water

● Appearance: Uniform reddish-brown powder

● Solubility: Easily soluble in hot water; good solubility at 80°C; aqueous solution is blueish-red

● Light Fastness: Grade 4–5

● Washing Fastness: Grade 3–4

● Dry Rubbing Fastness: Grade 4

● Wet Rubbing Fastness: Grade 3

● Dyeing pH: Neutral to weakly alkaline (pH 7–8.5)

● Ion Influence: Little effect from copper and iron ions; good shade stability

1.Dyeing Process Flow

Dye Dissolution → Fabric Pretreatment → Impregnation & Heating → Salt Promotion → Insulation Dyeing → Washing → Soaping → Fixation → Drying

2.Detailed Operating Steps

Step 1: Dye Dissolution

Mix evenly with 70–90°C hot soft water, stir until fully dissolved, filter and add to the dye vat.

Step 2: Fabric Pretreatment

Pre-wet fabric with 40–50°C warm water to remove size, oil and impurities.

Step 3: Dyeing

Start dyeing at 40–50°C, heat to 90–98°C at 1°C/min, hold for 40–60 minutes.

Step 4: Salt Promotion

Add 10–30 g/L of sodium sulfate in 1–2 batches to improve exhaustion.

Step 5: Fixation Treatment

Cationic fixing agent is recommended for high fastness requirements to further enhance wet fastness.

Step 6: After-Treatment

Cold wash → Hot wash → Soap at 80°C for 10 minutes → Thorough wash → Dry.

Dyeing Notes

● Controllable salt addition: Good leveling; salt can be added in batches or once

● Steady heating: Avoid rapid heating to ensure uniform dyeing

● Water quality: Soft water preferred; small amount of chelating agent allowed

● pH control: Neutral to weak alkaline optimum; avoid over-acid or over-alkali

● Optional fixation: Fixation recommended for high fastness; can be omitted for general requirements

1.Dissolution: Fully dissolve Direct Red 243 in 70–90°C hot water

2.Addition: Add during beating or mixing stage and stir evenly

3.Dosage: Adjust by shade depth; 0.1%–0.5% for light shades, 1%–3% for dark shades

4. Features: Stable shade, no yellowing, no fading, suitable for medium-to-high grade paper

1.Dissolution: Fully dissolve in hot water and filter to remove impurities

2.Bath pH: Neutral to weakly alkaline

3.Process: Can be used alone or in combination with direct yellow, orange, brown

4. Features: Full coloring, good penetration, stable shade

1.Dark shade

Cause: Poor water quality, metal ion interference, insufficient temperature

Solution: Use soft water + chelating agent; ensure holding temperature above 90°C

2.Low exhaustion rate

Cause: Insufficient sodium sulfate, oversized bath ratio, low temperature

Solution: Add proper salt; increase holding temperature and time

3.Insufficient washing fastness

Cause: No soaping, no fixation

Solution: Thorough soaping; fixation if necessary

4.Uneven dyeing

Cause: Rapid heating, insufficient dissolution

Solution: Fully dissolve dye; heat slowly

● Storage: Cool, dry, sealed, light-proof and moisture-proof

● Packing: 25kg woven bag or fiber drum

● Shelf Life: 2 years

● Safety: Industrial product; avoid dust inhalation; wear mask, gloves and goggles; not for food or food-contact materials

1.Always make lab trials before bulk production to confirm shade, fastness and strength

2.Fixation recommended for medium-to-high grade products

3.Record temperature, time, salt dosage and pH in detail for reproducibility

4.Can be combined with direct dyes; do not use with cationic dyes in same bath