Packaging bag with tear-off opening

Abstract

A packaging bag comprises a bag body, the first heat sealed portion, and the second heat sealed portion and a tear-starting portion. The bag body is made of a plastic laminate film having a pair of opposite side edges. The bag body is formed by bringing the pair of opposite side edges into contact with each other and heat-sealing them over their entirety to form a tubular shaped body having a rear heat sealed portion, and collapsing the tubular shaped body into a flatten shaped body having a front face, a rear face opposing the front face, a pair of opposite side edge portions connecting the front face and the rear face to each other, a first opened portion and a second opened portion opposing the first opened portion. The rear heat sealed portion is placed on the rear face. The first heat sealed portion is formed by heat-sealing the first opened portion. The second heat sealed-portion is formed by heat-sealing the second opened portion. The tear-starting portion is provided on at least one of the pair of opposite side edge portions and the rear heat sealed portion. The tear-starting portion comprises fine concavities opening outwardly.

1 . A packaging bag comprising: 
 a bag body made of a plastic laminate film having a pair of opposite side edges, said bag body being formed by bringing said pair of opposite side edges into contact with each other and heat-sealing them over their entirety to form a tubular shaped body having a rear heat sealed portion ( 102 ,  112 ,  122 ), and collapsing said tubular shaped body into a flatten shaped body having a front face ( 101 ,  111 ,  121 ), a rear face opposing said front face ( 101 ,  111 ,  121 ), a pair of opposite side edge portions connecting said front face ( 101 ,  111 ,  121 ) and said rear face to each other, a first opened portion and a second opened portion opposing said first opened portion, said rear heat sealed portion ( 102 ,  112 ,  122 ) being placed on said rear face;    a first heat sealed portion ( 104 ,  114 ,  124 ) being formed by heat-sealing said first opened portion;    a second heat sealed portion ( 103 ,  113 ,  123 ) being formed by heat-sealing said second opened portion; and    a tear-starting portion ( 105 ,  115 ,  125 ) from which said packaging bag is to be torn open, said tear-starting portion ( 105 ,  115 ,  125 ) being provided on at least one of said pair of opposite side edge portions, said tear-starting portion ( 105 ,  115 ,  125 ) comprising a plurality of fine concavities opening outwardly    characterized in that:    at least one of said first heat sealed portion ( 104 ,  114 ,  124 ) and said second heat sealed portion ( 103 ,  113 ,  123 ) is provided with said tear-starting portion ( 105 ,  115 ,  125 ); and    said at least one of said first heat sealed portion ( 104 ,  114 ,  124 ) and said second heat sealed portion ( 103 ,  113 ,  123 ) has a width, which varies from one of said pair of opposite side edge portions toward an other thereof, enabling said packaging bag to be torn in an arbitrary position in said tear-starting portion ( 105 ,  115 ,  125 ) to provide an opening having a size, which varies in accordance with a tearing position in said tear-starting portion ( 105 ,  115 ,  125 ).    
     
     
         2 . The packaging bag as claimed in  claim 1 , wherein: 
 said width gradually decreases from said one of said pair of opposite side edge portions toward said other thereof.    
     
     
         3 . The packaging bag as claimed in  claim 2 , wherein: 
 said tear-starting portion ( 105 ,  115 ,  125 ) is provided on said one of said pair of opposite side edge portions so as to extend over an entirety of said width having a maximum value.    
     
     
         4 . The packaging bag as claimed in any one of  claims 1  to  3 , wherein: 
 said plastic laminate film comprises an oriented plastic film layer serving as an outer layer and a non-oriented plastic resin layer serving as an inner layer; and  
 said tear-starting portion ( 105 ,  115 ,  125 ) is formed on said oriented plastic film layer.  
 
     
     
         5 . The packaging bag as claimed in  claim 4 , wherein: 
 said oriented plastic film layer is coated at its inner side with a polyvinylidene chloride film layer.    
     
     
         6 . The packaging bag as claimed in  claim 4 , wherein; 
 said oriented plastic film layer is coated at its inner side with a vapor-deposited metallic layer.    
     
     
         7 . The packaging bag as claimed in any one of  claims 1  to  3 ,  5  and  6 , wherein: 
 each of said first heat sealed portion ( 104 ,  114 ,  124 ) and said second heat sealed portion ( 103 ,  113 ,  123 ) has a flat edge.  
 
     
     
         8 . The packaging bag as claimed in  claim 4 , wherein: 
 each of said first heat sealed portion ( 104 ,  114 ,  124 ) and said second heat sealed portion ( 103 ,  113 ,  123 ) has a flat edge.