Isocyanathärdare

Isocyanathärdare are curing agents used in polyurethane chemistry to harden resin systems that contain isocyanate groups. In typical two-component polyurethane formulations, the isocyanate component reacts with the hardener to form polyurethane or polyurea networks, enabling a range of material properties. Hardeners are commonly amine-based, including polyamines and diamines, but can also be formulated as moisture-curing systems or blocked isocyanates that release active isocyanate groups on activation. Depending on the formulation, isocyanathärdare enable coatings, adhesives, sealants, foams, and elastomers with properties from flexible to rigid.

Hardener chemistries vary from simple chain extenders to highly functional curing agents. Amine hardeners react rapidly with isocyanates and are widely used in fast-curing coatings and rigid foams, while moisture-curing systems rely on environmental moisture to trigger curing. Some systems employ prepolymers or blocked isocyanates to improve handling, storage stability, or pot life before activation.

Safety and handling are central concerns. Isocyanates and many hardeners are respiratory and skin sensitizers and can cause asthma, dermatitis, or other hypersensitivity reactions. Handling requires adequate ventilation, engineering controls, and personal protective equipment such as gloves and respirators, along with proper training and safety data sheet compliance. Storage should be in tightly closed containers in a cool, dry place away from moisture and incompatible materials. In many jurisdictions they are classified as hazardous substances and subject to regulatory controls, including GHS labeling and chemical safety regulations. Proper disposal as hazardous waste is required.