Polyurethanes are an important component in major appliances consumers use every day.
The most common use for polyurethanes in major appliances is rigid foams for refrigerator and freezer thermal insulation systems. Rigid polyurethane foam can be a cost-effective material used to meet required energy ratings in consumer refrigerators and freezers. The good thermal insulating properties of rigid polyurethane foams result from the combination of a fine, closed-cell foam structure and cell gases that are poor heat conductors.
Modern refrigerators and freezers consist of a sheet metal outer casing and an inner liner made of polystyrene. In between these is a layer of rigid polyurethane foam that acts as both a structural and an insulating material that is applied and cured in appliance manufacturers’ assembly line. The adhesive properties of polyurethanes ensure a firm bond between the inner and outer walls, and also helps prevent heat exchange between the interior and exterior.
Polyurethane-based coatings are also used to paint appliances to achieve the aesthetic appeal consumers desire and to protect them from rust and heat.
Polyurethanes may also be found in tubing and wiring on major appliances. Thermoplastic polyurethanes (TPU) can be used as a cable sheathing material due to high flexibility even at sub-zero temperatures, high abrasion and wear resistance, and the ability to protect wiring from undesirable materials and other environmental influences.