Basic Information

Isophorone Diisocyanate, abbreviated as IPDI, is an important chemical product. Its chemical name is 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate. The CAS registry number for IPDI is 4098-71-9, and the EINECS number is 223-861-6. The molecular formula of IPDI is C12H18N2O2, with a molecular weight of approximately 222.29.

Physical Properties

IPDI is a colorless to light yellow liquid with a camphor-like odor. It is fully miscible with esters, ketones, ethers, aromatic hydrocarbons, and aliphatic hydrocarbons. The density of IPDI is 1.056, and its melting point is -60°C. The boiling point is 158°C at 15 mmHg. IPDI has a refractive index of 1.484 and a flash point above 110°C. Its water solubility is less than 0.1 g/100 mL at 25°C.

Chemical Characteristics

IPDI is a type of aliphatic isocyanate. It is a mixture containing 75% cis-isomer and 25% trans-isomer. The reactivity of IPDI is lower than that of aromatic isocyanates, and its vapor pressure is also relatively low. The two NCO groups in the IPDI molecule have different reactivities. Due to the steric hindrance of the cyclohexane ring and the α-substituted methyl group, the secondary NCO group attached to the cyclohexane ring reacts 1.3 to 2.5 times faster than the primary NCO group.

Applications

Due to its excellent optical stability and chemical resistance, IPDI is widely used in the manufacture of high-grade polyurethane resins, such as light-stable and weather-resistant polyurethane coatings, abrasion-resistant and hydrolysis-resistant polyurethane elastomers. IPDI can also be used to produce non-yellowing microcellular polyurethane foam plastics. Additionally, IPDI serves as a curing agent for hydroxyl prepolymers (i.e., polypropylene glycol) in polyurethane adhesives for composite propellants.

Safety and Handling

IPDI is harmful if inhaled, ingested, or absorbed through the skin. It is important to prevent vapor leakage into the workplace air. Operators must be specially trained and strictly adhere to operating procedures. Operators should wear a self-contained breathing apparatus with a full facepiece, rubber protective clothing, and rubber gloves. Keep away from ignition sources and heat. Smoking is strictly prohibited in the workplace. Use explosion-proof ventilation systems and equipment. Do not perform welding, cutting, or other similar operations until the liquid and vapor have been removed. Avoid contact with oxidants, alkalis, alcohols, and amines, especially water. Equip with appropriate fire-fighting equipment and emergency response equipment for leaks.

This introduction provides a comprehensive overview of IPDI, highlighting its basic information, physical properties, chemical characteristics, applications, and safety considerations.