How Is Sprayed Polyurethane Foam Made?

The tiny bubbles of air trapped in sprayed polyurethane foam help keep heat in.

Spray polyurethane is a rigid foam used for insulating buildings and in other applications where high insulating properties are required, such as refrigerated storage and hot water systems. It is made by mixing two chemicals with a foaming agent.

Features

Sprayed polyurethane foam is rigid, durable and moisture-resistant. Because it is a spray, it can be applied to surfaces of many shapes. Sprayed polyurethane foam is often used in building insulation.

Process

Sprayed polyurethane foam is made by mixing two chemicals in liquid form. These chemicals react, quickly forming a solid mass. If a blowing agent is added, the mixture will froth up. Blowing agents include fluorocarbons, CFCs and water. When the mixture hardens the air remains trapped inside the bubbles, making a rigid foam. If different additives are used, the result is a soft foam suitable for furnishings.

Considerations

Among the advantages of sprayed polyurethane foam are its insulating properties, strength and cost effectiveness. Because it is such a good insulator, a thinner layer of polyurethane foam is required than with many other insulating substances. Disadvantages include the use or production of harmful substances in making sprayed polyurethane foam. CFCs, for example, are known to be ozone-depleting gases.

References

• Polymer Science Learning Center: Making Polyurethane Foams
• Polyurethanes.org: Building Insulation
• SprayFoam.com: Spray Foam Formulations & Raw Materials
• Greenpeace International PVC Alternatives Database