Patent ID: 6911171

Claim:
A method for mass producing multi-layer thermoplastic closures for use in sealing fluid products in a container having a portal formed in the neck of the container, said closure having at least three separate and independent layers in intimate bonded interengagement with each other, said method comprising the steps of: A. extruding an elongated, substantially cylindrically shaped foam plastic core member; B. sequentially thereafter separately extruding a separate and independent first layer of plastic material in intimate bonded engagement with the core member, a. peripherally surrounding and substantially enveloping the cylindrical surface of the core member so as to prevent passage of any fluid between said two layers, b. comprising a thickness ranging between about 0.05 mm and 5 mm, and c. comprising a tough, score and mar resistant surface and a density ranging between about 300 kg/m 3 and 1500 kg/m 3 ; C. extruding a separate and independent second layer of plastic material in intimate bonded engagement with the first layer, a. peripherally surrounding and substantially enveloping the cylindrical surfaces of the first layer so as to prevent passage of any fluid between said layers, thereby establishing a multi-layer product; b. comprising a thickness ranging between about 0.05 mm and 5 mm, and c. comprising at least one additive selected from the group consisting of lubricating agents, slip-enhancing compounds, antimicrobial agents, antibacterial agents, and oxygen scavenging compounds; and D. separately extruding a separate and independent third layer of plastic material in intimate bonded engagement with the second layer, a. peripherally surrounding and substantially enveloping the cylindrical surface of the second layer so as to prevent passage of any fluid between said layers, thereby establishing a multi-layered product; b. comprising a thickness ranging between about 0.002 mm and 2 mm; and E. cutting said multi-layer product in a plane substantially perpendicular to the central axes of the cylindrically shaped core member, establishing a multi-layer thermoplastic closure having the desired length for insertion and retention in the portal of the neck of the container.