Diisotsünaatide

Diisotsünaatide, more commonly known as diisocyanates, are a group of organic compounds that contain two isocyanate functional groups. These groups, represented as -N=C=O, are highly reactive and are the key components in the production of polyurethanes. Diisocyanates are typically colorless to pale yellow liquids or solids with a pungent odor. They are often volatile and can pose health risks upon exposure.

The most widely produced and utilized diisocyanates are toluene diisocyanate (TDI) and methylene diphenyl diisocyanate (MDI). TDI is primarily used in the manufacture of flexible polyurethane foams, which are found in furniture, bedding, and automotive seating. MDI is used to produce rigid polyurethane foams, often employed as insulation in buildings and appliances, as well as in coatings, adhesives, sealants, and elastomers.

The reaction that defines polyurethane formation involves the addition polymerization of diisocyanates with polyols, which are compounds containing multiple hydroxyl (-OH) groups. This reaction creates a urethane linkage, forming the backbone of the polyurethane material. The properties of the resulting polyurethane can be extensively modified by selecting different types of diisocyanates and polyols.

Diisocyanates are considered hazardous materials. Inhalation of vapors or aerosols can lead to respiratory irritation, asthma-like symptoms, and occupational asthma, a serious and potentially irreversible condition. Skin contact can cause irritation and sensitization. Due to these health concerns, strict industrial hygiene practices, including ventilation and personal protective equipment, are essential when handling diisocyanates. Regulatory bodies worldwide have established exposure limits to protect workers.