Patent ID: 7972695

Claim:
A method for improving the resistance to leakage of a foam container comprising: obtaining expandable polystyrene particles having a diameter from about 0.008 to about 0.03 inches; impregnating the expandable polystyrene particles with a blowing agent; pre-expanding the expandable polystyrene particles to a density of from about 2 to about 12 pounds per cubic foot to form pre-expanded particles; applying a coating comprising liquid polyethylene glycol to the pre-expanded polystyrene particles; applying a solid component comprising a metal salt of higher fatty acids selected from the group consisting of zinc, magnesium, calcium, and aluminum salt of stearic, lauric, and myristic acid to the pre-expanded polystyrene particles; and heating the pre-expanded particles in a closed mold to further expand and form a foam container.