Methods of making thermal seals and perforations
AssigneePactiv Corporation
InventorsMichael L. Bohn, William P. Belias
Life of this patent
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Abstract
A method for simultaneously sealing and creating a thermal perforation between two thermoplastic layers that comprises providing two thermoplastic layers. A drum is provided that has at least one sealbar and perforation assembly. The two thermoplastic layers are contacted to the sealbar and perforation assembly. The thermoplastic layers are sealed with two generally opposing parallel seals and simultaneously create a thermal perforation in the thermoplastic layers generally parallel to the opposing seals. The thermal perforation is located between the two opposing seals.
Claims21
A method for simultaneously sealing and creating a thermal perforation between two thermoplastic layers, the method comprising:
- providing two thermoplastic layers;
- providing a drum having at least one sealbar and perforation assembly;
- providing a flexible backup surface and transporting the two thermoplastic layers between the drum and the flexible backup surface;
- contacting the two thermoplastic layers to the at least one sealbar and perforation assembly;
- and
- sealing the thermoplastic layers with two generally opposing parallel seals and simultaneously creating a thermal perforation in the thermoplastic layers generally parallel to the opposing seals, the thermal perforation being located between the two opposing seals.
A method of heating a sealbar and perforating assembly on a drum to form opposing seals and a thermal perforation between two thermoplastic layers, the method comprising:
- providing the sealbar and perforation assembly, the assembly comprising a first sealing surface, a second sealing surface and a perforation surface;
- providing at least one heat source to supply heat to the first and second sealing surfaces and a perforation surface, the material forming the first and second sealing surfaces having a lower coefficient of thermal conductivity than the material forming the perforation surface;
- heating the first and second sealing surfaces and the perforation surface using the at least one heat source;
- and
- removing heat from the first and second sealing surfaces and the perforating surface, the first and second sealing surfaces are at a lower temperature than the temperature of the perforation surface.
Dependencies are inferred from the claim text.