High-Purity Solvents, Polyurethane (PU) and Resin

Toluene-2,4-Diisocyanate (TDI)

Toluene-2,4-Diisocyanate (TDI), identified by CAS number 584-84-9, is a high-production-volume aromatic isocyanate that serves as a fundamental building block in the global polyurethane industry. It is characterized by its molecular formula $C_9H_6N_2O_2$ and consists of a benzene ring with a methyl group and two isocyanate functional groups at the 2 and 4 positions. While 2,4-TDI can be produced in pure form, it is most commonly utilized in industrial applications as an isomeric blend with 2,6-TDI (typically in 80/20 or 65/35 ratios).

At ambient temperatures, TDI exists as a clear to pale-yellow liquid with a sharp, pungent odor. Its primary chemical utility lies in its high reactivity toward polyols, forming polyurethane polymers through exothermic addition reactions. Due to its significant vapor pressure and status as a potent respiratory sensitizer, TDI is handled under strict regulatory oversight, requiring advanced ventilation and rigorous personal protective equipment (PPE) protocols to ensure worker safety.

Attributes

Key Features and Benefits

Rapid Processing Speeds: High chemical reactivity allows for fast curing times, which is essential for continuous high-speed foaming production lines.
Exceptional Resilience: Facilitates the production of flexible foams with high load-bearing capacity and excellent recovery properties.
Versatile Isomer Ratios: Can be blended or used as a pure isomer to fine-tune the morphology and mechanical strength of the resulting polymer.
Cost-Effectiveness: Provides one of the most economical pathways for the large-scale manufacture of low-density cellular plastics.
High NCO Content: A theoretical NCO content of 48.3% ensures high cross-linking efficiency per unit weight of the monomer.

Specifications

Technical Highlights

Molecular Weight: 174.16 g/mol.
Physical Properties: Boiling point of 251°C and a specific gravity of approximately 1.22 at 25°C.
Flash Point: 127°C (Closed Cup), classifying it as a combustible liquid.
Vapor Pressure: Approximately 0.01 mmHg at 25°C; volatility necessitates stringent inhalation exposure controls.
Solubility: Miscible with common organic solvents including ether, acetone, and benzene.
Moisture Sensitivity: Highly reactive with water, producing carbon dioxide ($CO_2$) and insoluble ureas; requires storage under a dry nitrogen blanket.
Viscosity: Low viscosity (approx. 3 mPa·s at 25°C) ensures ease of pumping and mixing in industrial dispensers.

Download Technical Data Sheet (TDS)

Practical industry uses

Applications

Flexible Polyurethane Foam: The dominant application for manufacturing mattresses, pillows, and upholstered furniture padding.
Automotive Interiors: Used extensively for molded seat cushions, headrests, armrests, and vibration-dampening components.
Industrial Coatings: Acts as a precursor for high-performance polyurethane floor coatings, wood finishes, and anti-corrosive marine paints.
Adhesives and Sealants: Formulated into high-strength bonding agents for construction, aerospace, and footwear industries.
Elastomers: Utilized in the production of castable elastomers for industrial rollers, wheels, and gaskets requiring high abrasion resistance.
Textile Treatments: Applied in specialty coatings for waterproof fabrics and synthetic leathers.