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Invention of Styrofoam

Invention of STYROFOAM™

In 1941, Dow invented a process for extruding polystyrene to achieve a closed-cell foam that resists moisture. Recognizing its superior insulating properties, buoyancy and “unsinkability”, it was originally adopted in 1942 by the U.S. Coast Guard.


Patented in 1944 as STYROFOAM™, this new material was lightweight but also durable, and exhibited outstanding thermal and moisture-resistant properties. The first application was as an “unsinkable” buoyancy billet by the U.S. Coast Guard in their six-man life rafts. Before the end of the war, both the Coast Guard and the U.S. Navy were using unsinkable STYROFOAM™ Brand Buoyancy Billets in a wide range of watercraft for the products’ insulation properties and buoyancy.

By the 1950s, STYROFOAM™ Brand products started making a significant impact in the construction market, replacing cork in varied low-temperature applications, and as a thermal barrier in the walls and roofs of institutional and commercial buildings. Pretty soon, the residential construction sector was using this indispensable material for below-grade insulation in the foundations and perimeters of slab-constructed homes.

Today, STYROFOAM™ Brand Insulation is one of the leading brands of insulation in the world. STYROFOAM™ Brand products are used in a variety of insulation applications, from rooftops to basement walls. Other applications range from marine buoyancy billets to core foam to floral, art and craft products.

Most STYROFOAM™ Brand products are easily recognized by a distinctive trademark BLUE™ color.