Foamed cellular particles of an expandable polymer composition

A system for optimizing the shipping and packaging of polymer particles for use in making foam articles, the steps comprising:

• at the polymer producer's plant,
• a) using expandable polymer particles with a bulk density ranging between about 40 pounds per cubic foot (641 kilograms per cubic meter) and about 32.0 pounds per cubic foot (513 kilograms per cubic meter) and a blowing agent in an amount less than about 10.0 weight % based on the weight of the polymer composition and heating said expandable particles at a temperature ranging between about 70° C. and about 110° C. and at a pressure ranging between about 10.1 psi absolute (70 kPa absolute)and about 24.7 psi absolute (170 kPa absolute) to form foamed cellular particles with a bulk density ranging from between about 34.3 pounds per cubic foot (550 kilograms per cubic meter) and about 12.5 pounds per cubic foot (200 kilograms per cubic meter) and with a blowing agent in an amount less than 6.0 weight % based on the weight of the polymer composition;
• b) packaging said foamed cellular particles of step a) whereby the required strength of the packages used in transporting the foamed cellular particles of step a) is lower than the required strength of packages used when transporting the expandable particles with a higher bulk density and higher blowing agent level of step a);
• and
• c) transporting said foamed cellular particles at a total shipment weight substantially equal to the total shipment weight of the expandable particles of step a) when transporting said expandable particles.