Tamper-evident package and method to make such a package

Abstract

A reclosable package ( 10 ) for the retail display of a food product and for the purchase and storage thereof by a consumer has tamper-evident features to enable the consumer to discern whether the package has been opened prior to purchase. The package ( 10 ) includes a header ( 26 ) formed by attaching the front and back sheets ( 12,14 ) of the package ( 10 ) to one another above the interlocking profiles ( 20,22 ) of the zipper ( 18 ) of the package ( 10 ) with a peel seal. Below the interlocking profiles ( 20,22 ), the front sheet ( 12 ) has a line of weakness ( 32 ), such as a line of perforations extending transversely across the package ( 10 ) below the interlocking profiles ( 20,22 ). A tear in the line of weakness ( 32 ) or a breach of the peel seal would readily indicate that the integrity of the package ( 10 ) has been compromised.

What is claimed is:  
     
         1 . A reclosable package comprising: 
 a front sheet and a back sheet, said front and back sheets defining said package having a top, a bottom a first side and a second side, said front sheet having a line of weakness running transversely thereacross at said top of said package, said front sheet and said back sheet being connected to one another along said bottom, first side and second side of said package; and    a zipper disposed transversely across said package between said front and back sheets and sealed thereto at said top of said package to provide a reclosable opening therefor, said zipper having two interlocking profiles each integrally formed with a web, one of said webs being sealed to the front sheet and the other of said webs being sealed to the back sheet, whereby said zipper is sealed to said front and back sheets, said interlocking profiles being above said line of weakness relative to said top and said front sheet being sealed to one of said webs below said line of weakness, said front and back sheets being connected to one another with a peel seal above said zipper, thereby forming a header above said zipper relative to said top, to provide said package with tamper-evident features.    
     
     
         2 . A reclosable package as claimed in  claim 1  wherein said front sheet and said back sheet are extruded from a thermoplastic resin material.  
     
     
         3 . A reclosable package as claimed in  claim 1  wherein said header has a hole for hanging said package.  
     
     
         4 . A reclosable package as claimed in  claim 1  wherein said header includes a portion in which said front sheet and said back sheet are not connected to one another with a peel seal, so that a user can grasp said front sheet and said back sheet at said portion and pull them apart to gain access to said zipper.  
     
     
         5 . A reclosable package as claimed in  claim 1  wherein said front sheet and said back sheet are joined to one another with a peel seal below said zipper relative to said top of said package to provide an additional tamper-evident feature.  
     
     
         6 . A reclosable package as claimed in  claim 1  wherein said line of weakness is a line of perforations across said front sheet.  
     
     
         7 . A reclosable package as claimed in  claim 1  wherein said line of weakness is a line of reduced thickness across said front sheet.  
     
     
         8 . A reclosable package as claimed in  claim 1  wherein said line of weakness is a score across said front sheet.  
     
     
         9 . A reclosable package as claimed in  claim 1  wherein said back sheet is thermoformed to provide a compartment for a food product.  
     
     
         10 . A reclosable package as claimed in  claim 1  wherein said zipper further comprises a slider to facilitate the opening and closing thereof.  
     
     
         11 . A method for making reclosable packages, said method comprising the steps of: 
 dispensing a back sheet from a first roll;    thermoforming said back sheet to provide a plurality of compartments for a food product;    dispensing a zipper having two interlocking profiles, each being integrally formed with a web, from a spool;    sealing the web of one of said two interlocking profiles to said back sheet to join said zipper to said back sheet;    dispensing a front sheet from a second roll;    providing said front sheet with a lengthwise line of weakness;    disposing said front sheet onto said zipper and back sheet with said line of weakness adjacent to said interlocking profiles;    sealing the web of the other of said two interlocking profiles to said front sheet opposite said line of weakness from said interlocking profiles;    forming a peel seal between said front sheet and said back sheet adjacent to said interlocking profiles opposite said interlocking profiles from said line of weakness, said peel seal and said line of weakness providing said package with tamper-evident features;    sealing said front sheet and said back sheet to one another at the bottom of said packages;    cross-sealing said front sheet and said back sheet to one another; and    separating each package from the next at the cross seals.    
     
     
         12 . A method as claimed in  claim 11  further comprising the step of deforming said zipper at intervals equal to the width of said reclosable packages.  
     
     
         13 . A method as claimed in  claim 12  further comprising the step of providing said zipper with a slider for each of said package-width intervals.  
     
     
         14 . A method as claimed in  claim 11  further comprising the step of dispensing a food product into said compartments.  
     
     
         15 . A method for making reclosable packages, said method comprising the steps of: 
 dispensing a thermoplastic sheet from a roll;    providing said thermoplastic sheet with a lengthwise line of weakness;    folding said thermoplastic sheet lengthwise to form a front sheet and a back sheet, said front sheet having said lengthwise line of weakness;    dispensing a zipper having two interlocking profiles, each being integrally formed with a web, from a spool;    feeding said zipper between said front sheet and said back sheet with said interlocking profiles of said zipper adjacent to said line of weakness;    sealing said webs of said zipper to said front and back sheets to join said zipper to said front sheet and back sheet, said front sheet being sealed to one of said webs opposite said line of weakness from said interlocking profiles;    forming a peel seal between said front sheet and said back sheet adjacent to said interlocking profiles and opposite to said interlocking profiles from said line of weakness, said peel seal and said line of weakness providing said package with tamper-evident features;    forming cross seals at intervals equal to the width of said reclosable packages; and    separating each package from the next at said cross seals.    
     
     
         16 . A method as claimed in  claim 15  wherein the step of providing said lengthwise line of weakness is carried out adjacent a lateral edge of said sheet.  
     
     
         17 . A method as claimed in  claim 15  wherein the step of providing said lengthwise line of weakness is carried out substantially down the center of said sheet and further comprising the step of sealing the lateral edges of said sheet to one another.  
     
     
         18 . A method as claimed in  claim 15  further comprising the step of deforming said zipper at intervals equal to the width of said reclosable packages.  
     
     
         19 . A method as claimed in  claim 18  further comprising the step of providing said zipper with a slider for each of said package-width intervals.  
     
     
         20 . A method as claimed in  claim 15  further comprising the step of dispensing a food product onto said sheet at intervals equal to the width of said reclosable packages.  
     
     
         21 . A method for making reclosable packages, said method comprising the steps of: 
 dispensing a thermoplastic sheet from a roll;    providing said thermoplastic sheet with a lengthwise line of weakness along one of its two edges;    forming said thermoplastic sheet into the shape of a tube;    dispensing a zipper having two interlocking profiles, each being integrally formed with a web, from a spool;    feeding said zipper between said two edges of said tube formed from said thermoplastic sheet with said interlocking profiles of said zipper adjacent to said lengthwise line of weakness;    sealing said webs of said zipper to said edges of said tube to join said zipper thereto, said edge having said lengthwise line of weakness being sealed to one of said webs opposite said lengthwise line of weakness from said interlocking profiles;    forming a peel seal between said two edges of said tube adjacent to said interlocking profiles and opposite said interlocking profiles from said lengthwise line of weakness, said peel seal and said line of weakness providing said package with tamper-evident features;    forming cross seals at intervals equal to the width of said reclosable packages; and    separating each package from the next at said cross seals.    
     
     
         22 . A method as claimed in  claim 21  further comprising the step of deforming said zipper at intervals equal to the width of said reclosable packages.  
     
     
         23 . A method as claimed in  claim 22  further comprising the step of providing said zipper with a slider for each of said package-width intervals.  
     
     
         24 . A method as claimed in  claim 21  further comprising the step of dispensing a food product into said tube of thermoplastic sheet after forming each of said cross seals.  
     
     
         25 . A method for making reclosable packages, said method comprising the steps of: 
 dispensing a thermoplastic sheet from a roll;    providing said thermoplastic sheet with a plurality of lines of weakness, each said line running transversely across said thermoplastic sheet for approximately one half of its width and being separated from adjacent lines of weakness by an interval equal to the length of said reclosable packages;    dispensing a zipper having two interlocking profiles, each being integrally formed with a web, from a spool;    cutting said zipper at intervals equal to the width of said reclosable packages and substantially equal in length to said lines of weakness;    sealing said cut zipper intervals to said thermoplastic sheet adjacent and substantially parallel to each of said lines of weakness, said webs being on one side of said lines of weakness and said interlocking profiles being on the other side of said lines of weakness;    folding said thermoplastic sheet lengthwise over said cut zipper intervals;    sealing the lateral edges of said thermoplastic sheet to one another;    sealing the folded thermoplastic sheet to said cut zipper intervals;    forming peel seals between said thermoplastic sheet and the folded portions thereof adjacent to said interlocking profiles and opposite said interlocking profiles from said lines of weakness, said peel seals and said lines of weakness providing said packages with tamper-evident features;    making cross seals at intervals equal to the length of said reclosable packages; and    separating the reclosable packages from one another.    
     
     
         26 . A method as claimed in  claim 25  further comprising the steps of deforming said zipper at intervals equal to the width of said reclosable packages and cutting the zipper at the deformed points.  
     
     
         27 . A method as claimed in  claim 26  further comprising the step of providing said cut zipper intervals with sliders.  
     
     
         28 . A method as claimed in  claim 25  further comprising the step of dispensing a food product into said thermoplastic sheet at intervals equal to the length of said packages.  
     
     
         29 . A method for making reclosable packages, said method comprising the steps of: 
 dispensing a thermoplastic sheet from a roll;    providing said thermoplastic sheet with a lengthwise line of weakness along one of its two edges;    folding said thermoplastic sheet lengthwise vertically to form a first sheet and a second sheet, said first sheet having said lengthwise line of weakness;    dispensing a zipper having two interlocking profiles, each being integrally formed with a web, from a spool;    feeding said zipper between said first sheet and said second sheet with said interlocking profiles of said zipper adjacent to said line of weakness;    forming cross seals at intervals equal to the width of said reclosable packages;    sealing said webs of said zipper to said first and second sheets to join said zipper to said first sheet and said second sheet, said first sheet being sealed to one of said webs opposite said line of weakness from said interlocking profiles;    separating said package from one another at said cross seals; and    forming a peel seal between said first sheet and said second sheet adjacent to said zipper, said peel seal and said line of weakness providing said package with tamper-evident features.    
     
     
         30 . A method as claimed in  claim 29  further comprising the step of deforming said zipper at intervals equal to the width of said reclosable packages.  
     
     
         31 . A method as claimed in  claim 30  further comprising the step of providing said zipper with a slider for each of said package-width intervals.  
     
     
         32 . A method as claimed in  claim 29  further comprising the step of dispensing a food product between said first and second sheets at intervals equal to the width of said reclosable packages before said zipper is sealed to both of said first and second sheets.  
     
     
         33 . A method as claimed in  claim 29  further comprising the steps of opening said zipper and of dispensing a food product between said first and second sheets at intervals equal to the width of said reclosable packages before the step of forming said peel seal.  
     
     
         34 . A method as claimed in  claim 31  further comprising the steps of using said slider to open said zipper and of dispensing a food product between said first and second sheets at intervals equal to the width of said reclosable packages before the step of forming said peel seal.  
     
     
         35 . A method for making reclosable packages, said method comprising the steps of: 
 dispensing a thermoplastic sheet from a roll;    providing said thermoplastic sheet with a lengthwise line of weakness running substantially down the center thereof between its two edges;    folding said thermoplastic sheet lengthwise vertically to form a first sheet and a second sheet, said first sheet having said lengthwise line of weakness;    dispensing a zipper having two interlocking profiles, each being integrally formed with a web, from a spool;    feeding said zipper between said first sheet and said second sheet with said interlocking profiles of said zipper adjacent said lengthwise line of weakness;    sealing said webs of said zipper to said first sheet and said second sheet to join said zipper to said first sheet and said second sheet, said first sheet being sealed to one of said webs opposite said line of weakness from said interlocking profiles;    forming a peel seal between said first sheet and said second sheet adjacent to said interlocking profiles and opposite said interlocking profiles from said line of weakness providing said package with tamper-evident features;    forming cross seals at intervals equal to the width of said reclosable packages;    sealing said first sheet to said second sheet along said two edges of said thermoplastic sheet; and    separating said packages from one another at said cross seals.    
     
     
         36 . A method as claimed in  claim 35  further comprising the step of deforming said zipper at intervals equal to the width of said reclosable packages.  
     
     
         37 . A method as claimed in  claim 36  further comprising the step of providing said zipper with a slider for each of said package-width intervals.  
     
     
         38 . A method as claimed in  claim 35  further comprising the step of dispensing a food product between said first and second sheets at intervals equal to the width of said reclosable packages before the step of sealing said first sheet to said second sheet along said two edges of said ‘thermoplastic sheet.