Patent ID: 7937912

Claim:
A method of manufacturing a container having multiple compartments, the method comprising: thermal welding a first sheet to a second sheet at a first temperature to form a periphery of the container that is able to withstand a predetermined stress, the periphery including at least two filling orifices, the first and second sheets being formed from a generally rigid heat-formable material; heating the first and second sheets to enable deformation of the first and second sheets; arranging the first and second sheets within a mold defining a predetermined shape; separating the first and second sheets with pressurized air blown into the mold such that the first and second sheets form a generally-rigid container having the predetermined shape, the generally-rigid container configured to include at least two compartments separated by a seal line collectively defined by the first and second sheets within the periphery; and thermal welding the first sheet to the second sheet along the seal line at a second temperature lower than the first temperature to form a frangible seal between the at least two compartments of the generally-rigid container, the frangible seal being frangible under the predetermined breaking stress based on the second temperature, wherein a liquid placed in at least one of the compartments and frozen within the at least one compartment of the generally-rigid container would exert a stress on the frangible seal higher than the predetermined stress, thereby breaking the frangible seal so that the liquid would mix into the other of the compartments.