Resistance of polyurethane sealants to hot water

The resistance of polyurethane sealants to immersion in hot water is an important consideration for durability and performance. The effects of some chemical compositions in the improvement of the resistance to hot water immersion are tested and evaluated. Polyurethane sealants made from a hydrophobic polyol are shown to exhibit more persistent hotwater resistance than those made from the commonly used polypropylene glycol diol (PPG). The compromises between adhesion, cohesion, water swelling and thermal oxidation for different formulations are discussed.