Thioindigo (Vat Red 41)
CAS Number: 522-75-8
Thioindigo is a sulfur-analogue of indigo in which the NH groups are replaced by sulfur atoms, producing a brilliant red vat dye with excellent lightfastness and chlorine fastness. It is used to dye cotton in vivid red shades that retain color depth after repeated washing and exposure to light. Chemzip supplies thioindigo for high-quality cotton dyeing and specialty pigment applications requiring outstanding durability.
Technical Specifications
| appearance | Dark red to maroon powder |
| purity (%) | ≥93.0 |
| moisture (%) | ≤2.0 |
| shade (vs. reference) | 98–102% |
Applications
- High-fastness red vat dyeing of cotton and linen
- Workwear and uniform fabric dyeing for red shades
- Specialty textile printing requiring superior lightfastness
- Organic pigment for high-durability coatings and plastics
- Artist pigment for oil and watercolor applications
Key Features
- Outstanding ISO lightfastness rating 7-8 for exterior and technical textiles
- Chlorine-resistant for swimwear and sportswear dyeing applications
- Shade-matched against international reference standard per batch
- Available in both powder and pre-dispersed paste formulations
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CAS Number
522-75-8
Category
Dye / Pigment IntermediatesAvailability
In StockSample
Dispatched within 5 days