Multi-layer web and process for forming scored lidding film for blister packages

Abstract

Multi-layer web and mechanical scoring process for forming lidding film for push through blister packages. The web is configured to resist the tensile forces encountered during manufacturing processes, including slitting, rewinding and heat sealing processes. A simplified web conversion process for creating mechanically scored lidding film for blister packages is provided at reduced investment and operational costs compared to prior art systems.

What is claimed is: 
     
         1 . A multi-layer web comprising:
 a multi-layer web of film windable on a core and adapted to be scored and slit to form scored lidding film for blister packages, the film being formed without a metal layer and including an inner seal layer and an outer layer of different thermoplastic polymer materials,   the inner seal layer configured to form a thermal weld seal with a base substrate of a blister package, while the outer layer has a central scored area configured to rupture and release a product contained in a recess of a base substrate without breaking the weld seal,   the web being unwound from the core in a machine M direction transverse to a central longitudinal axis CL of the core on which the web is wound,   the central scored area extending between opposing first and second non-scored edge grip areas aligned in the M direction, the central scored area being sized to cover a plurality of recesses in a base substrate of a blister package without the need for registering the scored area with individual recesses,   the central scored area being formed by passing the web against a scoring roller to mechanically score fully or partially through the outer layer without scoring the inner seal layer,   the opposing first and second edge grip areas being non-scored and each of a minimum width configured to provide structural integrity to the web during winding and unwinding of the web onto or from the core, and   the non-scored edge grip areas being slit to form a scored lidding film for blister packages,   wherein the central scored area comprises 75% to 99% of a total width of the lidding film and the non-scored edge grip areas together comprise 1% to 25% of the total width   
     
     
         2 . A multi-layer web of  claim 1 , wherein the central scored area comprises 80% to 99% of the total width. 
     
     
         3 . A multi-layer web of  claim 1 , wherein the central scored area comprises 85% to 99% of the total width. 
     
     
         4 . A multi-layer web of  claim 1 , wherein the scoring depth is between and 10% and 90% of the outer layer thickness. 
     
     
         5 . A multi-layer web of  claim 1 , wherein the scoring depth is between 20% and 80% of the outer layer thickness. 
     
     
         6 . A multi-layer web of  claim 1 , wherein the scoring depth is between 30% and 70% of the outer layer thickness. 
     
     
         7 . A multi-layer web of  claim 1 , wherein the scoring comprises spaced apart arrow shaped scored formations aligned in the M direction. 
     
     
         8 . A multi-layer web of  claim 1 , wherein the inner layer comprises 5% to 50% of the total film thickness and the outer layer comprises 50% to 95% of the total film thickness. 
     
     
         9 . A multi-layer web of  claim 1 , wherein the inner layer comprises 5% to 40% of the total film thickness and the outer layer comprises 60% to 95% of the total film thickness. 
     
     
         10 . A multi-layer web of  claim 1 , wherein the inner layer comprises 5% to 30% of the total film thickness and the outer layer comprises 70% to 95% of the total film thickness. 
     
     
         11 . A multi-layer web of  claim 1 , wherein the lidding film is from 10 to 100 micron in thickness. 
     
     
         12 . A multi-layer web of  claim 1 , wherein the lidding film is from 15 to 90 micron in thickness. 
     
     
         13 . A multi-layer web of  claim 1 , wherein the lidding film is from 20 to 80 micron in thickness. 
     
     
         14 . A multi-layer web of  claim 1 , wherein the scoring is uniformly distributed in the central area. 
     
     
         15 . A multi-layer web of  claim 1 , wherein the scoring width is from 5 to 100 microns. 
     
     
         16 . A lidding film formed from the multi-layer web of  claim 1 , combined with a thermoformed base substrate, the inner layer being weld sealed to the base substrate. 
     
     
         17 . A lidding film and base substrate of  claim 16 , cut to form a single blister package. 
     
     
         18 . A lidding film and base substrate of  claim 16 , made from materials compatible in recycling. 
     
     
         19 . A lidding film and base substrate of  claim 18 , both made from polypropylene. 
     
     
         20 . A lidding film and base substrate of  claim 18 , both made from polyester. 
     
     
         21 . A multi-layer web of  claim 1 , wherein the multi-layer web is formed by co-extrusion of the inner seal layer and outer layer, extrusion coating of the inner seal layer onto the outer layer, or coating of the inner seal layer onto the outer layer via solvent, water or solventless coating processes or by wet or dry bond lamination of the inner seal layer to the outer layer. 
     
     
         22 . A multi-layer web of  claim 1 , wherein the outer layer comprises polyester or polyolefin. 
     
     
         23 . A multi-layer web of  claim 1 , wherein the outer layer comprises polyethylene terephthalate or polypropylene, including homopolymers, copolymers and blends thereof. 
     
     
         24 . A multi-layer web of  claim 1 , wherein the inner layer comprises ethylene vinyl acetate, polyester, polyethylene, polypropylene, or acrylic, including homopolymers, copolymers and blends thereof. 
     
     
         25 . A multi-layer web of  claim 1 , wherein the outer layer comprises semi-crystalline polyethylene terephthalate and the inner layer comprises an amorphous polyethylene terephthalate copolymer. 
     
     
         26 . A multi-layer web of  claim 1 , wherein the outer layer comprises homopolymer polypropylene and the inner layer comprises polypropylene copolymer. 
     
     
         27 . A method of forming blister packages comprising steps of:
 providing a master roll of the multi-layer web of  claim 1 , the master roll configured to form scored lidding film for multiple blister packages across a width W of the master roll transverse to the M direction,   unwinding a length of the master roll in the M direction,   passing the length of the master roll against a scoring roller to mechanically score only the outer layer of the film, wherein multiple central scored areas are formed across the width of the master roll between non-scored areas,   slitting the master roll along the M direction in the non-scored edge grip areas between two central scored areas to form multiple slit rolls of scored lidding film,   unwinding a slit roll of lidding film and attaching a series of base substrates along a length of the unwound slit roll to form a series of blister packages.   
     
     
         28 . A method of  claim 27 , further comprising cutting individual blister packages from the series of blister packages. 
     
     
         29 . An apparatus for forming blister packages according to the method of  claim 27  including a plurality of stations for in-line forming of a series of blister packages, the stations comprising:
 a base forming station for unwinding a roll of base film from a core in a machine direction M, followed by heating and thermoforming the base film to form a series of thermoformed base substrates with product recesses in the base film aligned along the M direction, 
 a filling station for dispensing product into the recesses of the series of base substrates, 
 a thermal sealing station, receiving the filled series of base substrates and a slit roll of scored lidding film, for sealing the inner layer of the scored lidding film to the filled base substrates to form a series of sealed blister packages, and 
 a cutting station for cutting individual blister packages from the series. 
 
     
     
         30 . An apparatus for forming blister packages including a plurality of stations for in-line forming of a series of blister packages, the stations comprising:
 a base forming station for unwinding a roll of base film from a core in a machine direction M, followed by heating and thermoforming the base film to form a series of thermoformed base substrates with product recesses in the base film aligned along the M direction,   a filling station for dispensing product into the recesses of the series of base substrates,   a roll of scored lidding film on a core having a series of central scored areas between nonscored areas aligned along a machine direction M,   a thermal sealing station, receiving the series of filled base substrates and a length of the scored lidding film unwound from the core in the M direction, wherein the inner layer of the scored lidding film is sealed to each filled base substrate with the central scored area over the recesses of the substrate to form a series of sealed blister packages, and   a cutting station for cutting individual blister packages from the series.