A method for producing multi-component closures comprising at least one thermoplastic polymer for being inserted and securely retained in a portal-forming neck of a container, said method comprising the steps of: a. extruding a continuous, elongated substantially cylindrically shaped length of a material for forming the core member of the closure; b. optionally, separately extruding one or several separate and independent layer(s) of plastic material in intimate bonded engagement with the continuous, elongated length of material forming the core member or, in the case of several independent layers, in intimate bonded engagement with the respective outermost independent layer formed on the continuous, elongated length of material, said separate and independent layer(s) of plastic material peripherally surrounding and substantially enveloping the cylindrical surface of the continuous, elongated length of material and forming a multi-component product; c. passing the continuous, elongated, substantially cylindrically shaped length of material obtained in method step a. or in method step b. through a printer system for printing desired indicia on the lateral surface of said continuous, elongated length of material, d. separately extruding one or several separate and independent layer(s) of plastic material in intimate bonded engagement with the continuous, elongated length of material obtained in method step c. or, in the case of several independent layers, in intimate bonded engagement with the respective outermost independent layer formed on the continuous, elongated length of material, said separate and independent layer(s) of plastic material peripherally surrounding and substantially enveloping the cylindrical surface of the continuous, elongated length of material obtained in method step c. and being in overlying relationship with the indicia printed in method step c. and forming a multi-component product; and e. cutting the multi-component product obtained in method step d. in a plane substantially perpendicular to the central axis of the elongated length of material forming the core member, establishing a multi-component closure comprising at least one thermoplastic polymer and having the desired length for insertion and retention in the portal of the neck of the container, wherein said printing step comprises the use of invisible ink, wherein at least a registration mark is printed in the printing step, wherein said registration mark comprises invisible ink and characterized in that the registration mark is detected by the cutting machine in method step e. a. extruding a continuous, elongated substantially cylindrically shaped length of a material for forming the core member of the closure; b. optionally, separately extruding one or several separate and independent layer(s) of plastic material in intimate bonded engagement with the continuous, elongated length of material forming the core member or, in the case of several independent layers, in intimate bonded engagement with the respective outermost independent layer formed on the continuous, elongated length of material, said separate and independent layer(s) of plastic material peripherally surrounding and substantially enveloping the cylindrical surface of the continuous, elongated length of material and forming a multi-component product; c. passing the continuous, elongated, substantially cylindrically shaped length of material obtained in method step a. or in method step b. through a printer system for printing desired indicia on the lateral surface of said continuous, elongated length of material, d. separately extruding one or several separate and independent layer(s) of plastic material in intimate bonded engagement with the continuous, elongated length of material obtained in method step c. or, in the case of several independent layers, in intimate bonded engagement with the respective outermost independent layer formed on the continuous, elongated length of material, said separate and independent layer(s) of plastic material peripherally surrounding and substantially enveloping the cylindrical surface of the continuous, elongated length of material obtained in method step c. and being in overlying relationship with the indicia printed in method step c. and forming a multi-component product; and e. cutting the multi-component product obtained in method step d. in a plane substantially perpendicular to the central axis of the elongated length of material forming the core member, establishing a multi-component closure comprising at least one thermoplastic polymer and having the desired length for insertion and retention in the portal of the neck of the container, wherein