Films, packaging and methods for making them

Abstract

There is described an optionally flexible and/or polymeric packaging film (e.g. BOPP) having at least one tear line ( 5 ) and at least one tab ( 7 ) thereon, where the tab ( 7 ) has a free end, an end attached to the film and free sides connecting the two ends, the tab ( 7 ) positioned so the axis of at least one tear line ( 5 ) passes through both ends of the tab ( 7 ) characterised in that: (a) at least one of the free sides of the tab ( 7 ) taper outwardly from the attached end and the tear line ( 5 ); and (b) at least one angle theta (θ) is an acute angle greater than about 5° where theta (θ) is defined as an angle subtending the free end of the tab ( 7 ) measured between: (i) an axis defined by the average direction of one of the tab ( 7 ) sides averaged over a the last quarter of the maximum length of the tab ( 7 ) starting from the attached end; and (ii) an axis defined by the average direction of the tear line ( 5 ) along the film. A method of preparing such films and packaging articles (such as cigarette cartons) over-wrapped with such films are also described.

1 . A packaging film having at least one tear line and at least one tab thereon, where the tab has a free end, an end attached to the film and free sides connecting the two ends, the tab positioned so the axis of at least one tear line passes through both ends of the tab characterized in that: 
 (a) at least one of the free sides of the tab taper outwardly from the attached end and the tear line; and    (b) at least one angle theta (θ) is an acute angle greater than about 5° where theta (θ) is defined as an angle subtending the free end of the tab measured between 
 (i) an axis defined by the average direction of one of the tab sides averaged over a the last quarter of the maximum length of the tab starting from the attached end; and  
 (ii) an axis defined by the average direction of the tear line along the film.  
   
   
   
       2 . A film as claimed in  claim 1 , in which the axis (i) is defined as the direction of one of the tab sides substantially adjacent to the attached end of the tab.  
   
   
       3 . A film as claimed in  claim 1 , in which the axis (ii) is parallel to the at least one tear line where the line crosses the attached end of the tab.  
   
   
       4 . A film as claimed in  claim 1;  in which both free sides of the tab taper outwardly and both values for theta (θ) either side of the tear line are an acute angle greater than about 5°.  
   
   
       5 . A film as claimed in  claim 1 , in which the tab is substantially symmetrical about the at least one tear line and theta (θ) is substantially the same on both sides of tab either side of the tear line.  
   
   
       6 . A film as claimed in  claim 1 , where the at least one angle theta (θ) is from about 10° to about 80°.  
   
   
       7 . A film as claimed in  claim 6 , where the at least one angle theta (θ) is from about 15° to about 60°.  
   
   
       8 . A film as claimed in  claim 7 , where the at least one angle theta (θ) is from about 20° to about 45°.  
   
   
       9 . A film as claimed in  claim 8 , where the at least one angle theta (θ) is about 30°.  
   
   
       10 . A film as claimed in  claim 1;  which comprises a narrow neck with sides substantially parallel to the tear line connecting the angled tab sides with the attached end of the tab.  
   
   
       11 . A film as claimed in  claim 1 , in which the film comprises a pair of tear lines defining a tear strip on the film and/or the tear line comprises a separate tear tape, where the tab is positioned so that both ends straddle the strip and/or tape.  
   
   
       12 . A film as claimed in  claim 11;  in which the tab is shaped so that part of the tab is wider that the tear strip and/or tear tape.  
   
   
       13 . A film as claimed in  claim 11 , in which the tear line on the film consists of a pair of tear lines defining a tear strip integral to the film.  
   
   
       14 . A film as claimed in  claim 1 , in which the tear line comprises a scored and/or partially cut line in the film and/or a line of weakness caused by differential and/or scrambled orientation of the film material within the line compared to the rest of the film.  
   
   
       15 . A film as claimed in  claim 1 , in which the tear line has substantially the same gauge as the rest of the film.  
   
   
       16 . A film as claimed in  claim 1 , in which the film is substantially oriented in at least one direction.  
   
   
       17 . A film according to  claim 1 , which comprises a thermoplastic polymer.  
   
   
       18 . A film according to  claim 1 , which comprises a polyolefin and/or polyester.  
   
   
       19 . A film according to  claim 1 , which comprises polypropylene.  
   
   
       20 . A film as claimed in  claim 1 , which is biaxially oriented in substantially perpendicular directions.  
   
   
       21 . A film according to  claim 1  in which the tear line is formed by laser treatment.  
   
   
       22 . A film according to  claim 21 , in which has a means thereon to indicate the position for initiating tearing of the film by pulling the tab along at least one tear line.  
   
   
       23 . (Cancelled)  
   
   
       24 . A package comprising at least one article wrapped in a flexible polymeric film as claimed in  claim 1 .  
   
   
       25 . A package as claimed in  claim 24 , which is capable of being opened by finger pressure by pulling the tab substantially along the tear line.  
   
   
       26 . A package according to  claim 24 , in which the film has been sealed around the article and tearing occurs with peeling of the seal.  
   
   
       27 . A package according to  claim 24 , in which the film has been heat sealed around the article.  
   
   
       28 . A package according to  claim 24 , in which the article is comprises tobacco goods, optionally a cigarette carton.  
   
   
       29 . A method for preparing a film having at least one tear line and at least one tab thereon, the method comprising the steps of: 
 (I) directing onto a web of film a means to make at least one tear line thereon; and    (II) forming at least one tab on the film, where the tab has a free end, an end attached to the film and free sides connecting the two ends, the tab positioned so the axis of at least one tear line passes through both ends, characterised in that: 
 (a) at least one of the free sides of the tab taper outwardly from the attached end and the tear line; and  
 (b) at least one angle theta (θ) is acute where theta (θ) is defined as an angle subtending the free end of the tab measured between 
 (i) an axis defined by the average direction of one of the tab sides averaged over a the last quarter of the maximum length of the tab starting from the attached end; and  
 (ii) an axis defined by the average direction of the tear line along the film.  
 
   
   
   
       30 . A method as claimed in  claim 29 , further comprising sequentially and/or simultaneously with the other steps the further step of: 
 (III) separating the film web into sheets along a sheet line in the TD, where the sheet line stops at the tab sides or slightly penetrates the tab sides but does not sever the tab along the axis of the sheet line.    
   
   
       31 . (Cancelled)  
   
   
       32 . A film obtained and/or obtainable by the method claimed in  claim 29.