Method of forming a closure for a fluid collection tube

A method for manufacturing closures for evacuated fluid collection tubes, said tube having a cylindrical wall with a selected inside diameter, said method comprising the steps of:

• providing a sheet of laminated sealing material having a first outer layer formed from a thermoplastic material, an intermediate layer of metallic foil adjacent said first outer layer and a second outer layer;
• moving said sheet to a molding apparatus;
• molding substantially cylindrical elastomeric stoppers onto substantially planar sections of said second outer layer of said sheet at spaced apart locations on said sheet, the substantially cylindrical elastomeric stoppers having outside diameters approximately equal to or slightly greater than said inside diameter of said cylindrical side wall of said fluid collection tubes;
• cutting said sheet into selected circular shapes surrounding portions of each said stopper on said sheet, said circular shapes defining diameters greater than the diameters defined by said stopper and greater than said inside diameter of said fluid collection tubes, such that an annular area of said second outer layer of said sealing material projects outwardly from said stopper,
• providing a plurality of outer caps, each said outer cap having a cylindrical skirt with too and bottom ends, an annular shoulder extending inwardly from said top end of said skirt and an aperture formed centrally in said annular shoulder, said annular shoulder having a bottom surface facing toward said bottom end of said skirt;
• and
• adhering said first outer layer of said seal to said bottom surface of said annular shoulder such that said stopper is disposed within and spaced from said skirt.