Medical freezer bag

Abstract

A medical freezer bag having a sufficient strength, which is not damaged at −196° C., the temperature of liquid nitrogen, and is excellent in low temperature resistance and molding processability, and whole blood, body fluids, and cell suspensions can be aseptically or nontoxically preserved at extremely low temperatures, is provided. The freezer bag is made from a three-layer film where both sides of an ultra-high molecular weight polyethylene film are welded respectively with a thermoplastic resin film having a lower melting point than that of the ultra-high molecular weight polyethylene and having compatibility with the ultra-high molecular weight polyethylene.

1 . A medical freezer bag comprising a three-layer film where each of both sides of an ultra-high molecular weight polyethylene film is welded to a thermoplastic resin film having a lower melting point than that of the ultra-high molecular weight polyethylene and having compatibility with the ultra-high molecular weight polyethylene.  
     
     
         2 . The medical freezer bag according to  claim 1 , wherein the thermoplastic resin is an ethylene-vinyl acetate copolymer, an ethylene-methacrylic ester copolymer, or a linear low-density polyethylene.  
     
     
         3 . The medical freezer bag according to  claim 1 , wherein the ultra-high molecular weight polyethylene has a measured viscometric weight average molecular weight of 1,000,000 or more, or a weight average molecular weight of 3,000,000 or more measured based on a light scattering method.  
     
     
         4 . The medical freezer bag according to  claim 1 , wherein the three-layer film has a thickness of approximately 50 to 500 μm.  
     
     
         5 . The medical freezer bag according to  claim 4 , wherein the three-layer film has a thickness of approximately 100 to 250 μm.  
     
     
         6 . A method of molding a medical freezer bag, characterized by molding (1) a three-layer film obtained by welding each of both sides of an ultra-high molecular weight polyethylene film with a thermoplastic resin film having a lower melting point than that of the ultra-high molecular weight polyethylene and having compatibility with the ultra-high molecular weight polyethylene, and (2) a port member.  
     
     
         7 . A method of storing a medical freezer bag, characterized by filling the medical freezer bag with blood, a body fluid, or a cell suspension; and storing the medical freezer bag at a temperature ranging from approximately −80 to −196° C., wherein the medical freezer bag comprises a three-layer film where each of both sides of an ultra-high molecular weight polyethylene film is welded to a thermoplastic resin film having a lower melting point than that of the ultra-high molecular weight polyethylene and having compatibility with the ultra-high molecular weight polyethylene.