a collapsible container for facilitating the transportation and handling of heat meltable materials , such as , e . g ., caprolactam , hexamethylene diamine , dodecanedioic acid , or any monomer and salt combinations used in the production and polymerization of polyamides . an expandable / collapsible container or bag is employed for holding and dispensing the bulk material . the bulk material is transported in a solid form , and converted to liquid form for removal from the container . the container includes heat tubing circulating a heat carrying medium or a heating element for heating and converting the bulk material to liquid form . the liquified material is then pumped from the container into a suitable storage facility .