TDI
Everything You Need to Know About TDI
TDI (Toluene Diisocyanate) is a crucial chemical compound widely used in polyurethane production. As industry professionals with decades of experience, we present this comprehensive guide to help you understand TDI's specifications, applications, and safety considerations.
Key Product Specifications
- Chemical Name: Toluene Diisocyanate
- CAS Number: 584-84-9 (2,4-TDI) / 91-08-7 (2,6-TDI)
- Molecular Formula: C9H6N2O2
- Appearance: Clear, colorless to pale yellow liquid
- Odor: Sharp, pungent
- Boiling Point: 251°C (484°F)
- Flash Point: 132°C (270°F)
Technical Parameters
| Parameter | 2,4-TDI | 2,6-TDI | Mixed Isomer |
|---|---|---|---|
| Purity (%) | ≥99.5 | ≥99.5 | 80/20 or 65/35 |
| NCO Content (%) | 48.0-48.5 | 48.0-48.5 | 47.5-48.5 |
| Specific Gravity (25°C) | 1.22 | 1.22 | 1.22 |
| Viscosity (mPa·s at 25°C) | 3 | 3 | 3 |
TDI Applications
TDI serves as a key raw material in numerous industrial applications:
- Flexible polyurethane foam production (mattresses, furniture, automotive seats)
- Rigid foam insulation for appliances and construction
- Coating and adhesive formulations
- Elastomer production for wheels, rollers, and shoe soles
- Automotive interior components
TDI FAQ Section
Q: What safety precautions should be taken when handling TDI?
A: TDI requires careful handling due to its toxicity and reactivity. Always use appropriate PPE including chemical-resistant gloves, goggles, and respiratory protection. Work in well-ventilated areas with local exhaust ventilation. Have emergency wash stations available and avoid skin contact. Store TDI in cool, dry places away from incompatible materials like water, alcohols, and amines.
Q: What are the primary differences between 2,4-TDI and 2,6-TDI isomers?
A: The main difference lies in their molecular structure and reactivity. 2,4-TDI has two reactive NCO groups at positions 2 and 4 of the benzene ring, making it more reactive than 2,6-TDI where the groups are at positions 2 and 6. This affects cure rates and final product properties - 2,4-TDI produces faster-curing systems while 2,6-TDI offers better flow characteristics. Commercial products often use isomer mixtures to balance these properties.
Q: How should TDI be stored to maintain quality?
A: Store TDI in sealed containers under dry nitrogen blanket to prevent moisture absorption. Maintain temperature between 15-25°C (59-77°F). Avoid contamination from water or other reactive chemicals. Under proper conditions, TDI typically has a shelf life of 6-12 months. Monitor NCO content periodically as quality indicator.
Handling and Transportation
TDI requires specialized handling during transportation:
- UN number: UN2078
- Proper shipping name: TOLUENE DIISOCYANATE
- Hazard class: 6.1 (Toxic)
- Packing group: II
- Transport in stainless steel or properly lined containers
- Temperature control may be required in extreme climates
Environmental Considerations
Proper TDI management includes environmental protection measures:
- Prevent spills reaching water systems or soil
- Containment systems should be in place at storage areas
- Waste disposal must follow local regulations
- Consider vapor recovery systems during handling
- Monitor workplace air concentrations regularly
Market Trends and Availability
The global TDI market continues to evolve with these key trends:
- Increasing demand from Asia-Pacific region
- Ongoing capacity expansions by major producers
- Technological advancements in production processes
- Growing applications in automotive and construction sectors
- Strictening environmental regulations affecting production