Patent ID: 8904810

Claim:
An improved method for maintaining temperature sensitive material at sub-ambient temperatures comprising the steps of: determining a need to maintain said temperature sensitive material at from −7° C. to −20° C. for at least 47 hours; obtaining a closeable, insulated container that is able to contain said temperature sensitive material therein; wherein said closeable, insulated container has an airtight lid and, when closed, has an inner container surface, defines an interior center, and forms an airtight vapor barrier, selecting a sodium chloride and water solution phase change material (PCM) appropriate for said 47 hour time period and said temperature range; cooling said PCM so that a starting temperature of said PCM material immediately before closure of said closeable, insulated container for shipment thereof is lower than a melting temperature of said PCM material, establishing a layered, insulated PCM assemblage inside of said inner container surface and to fully surround said temperature sensitive material, and maintaining said temperature sensitive material at from said −7° C. to −20° C. for said at least 47 hours; wherein said layered, insulated PCM assemblage itself comprises: double layered, foil-foam-foil insulating foam material enclosed PCM sections established between said insulating foam material and said interior center, said enclosed PCM sections established so as to fully surround said temperature sensitive material, additional enclosed PCM sections established between said insulating foam material and said inner container surface, wherein said additional enclosed PCM sections comprise enclosed PCM sheets, wherein said step of establishing a layered, insulated PCM assemblage inside of said inner container surface and to fully surround said temperature sensitive material comprises the step of closing said airtight lid, and wherein said method does not comprise using dry ice in any manner.