Packaging bag with zipper

Abstract

A packaging bag with zipper is provided, which enables easy identification whether or not the bag has been opened. For this purpose, in the packaging bag with zipper, the lower end portion of a male zipper tape and the lower end portion of a female zipper tape are bonded to the inner faces of respective front side and rear side sheet sections, or vice versa, along the opening end of the bag. The opening end comes at the top when the bag is in an upright state. The respective zipper tapes are bonded together at a position below the engaging section of the zipper tapes with heat sealing strength of a degree that allows the zipper tapes to be manual peeling apart, in such a manner that they may be manually peeled apart by an interface peeling action, an interlayer peeling action, or a cohesive peeling action.

What is claimed is:  
     
         1 . A packaging bag with zipper, in which a lower end portion of a male zipper tape and a lower end portion of a female zipper tape are bonded to inner faces of respective front side and rear side sheet sections, or rear side and front side sheet sections, along an opening end of the bag, the opening end being located at an upper en of the bag when the bag is in an upright state, wherein 
 the respective zipper tapes are bonded together at a position below an engaging section of the zipper tapes, with heat sealing strength of a degree that allows the bonded zipper tapes to be manually peeled apart, by means of an interface peeling action, an interlayer peeling action, or a cohesive peeling action.    
     
     
         2 . The packaging bag with zipper according to  claim 1 , wherein one of the zipper tapes is made from a hot melt type adhesive resin, and the other zipper tape is made from a polyethylene type resin or polypropylene type resin of a same kind as a material forming inner layers of the bag.  
     
     
         3 . The packaging bag with zipper according to  claim 1 , wherein either one of the zipper tapes is made from a hot melt type adhesive resin, and both the outer face and the inner face of the other zipper tape are made from a polyethylene type resin or a polypropylene type resin of a same kind as a material forming the inner layer of the bag.  
     
     
         4 . The packaging bag with zipper according to  claim 1 , wherein one of the zipper tapes is made from a hot melt type adhesive resin, and the other zipper tape is made to have an outer face made from a polyethylene type resin or polypropylene type resin of a same kind as a material forming inner layers of the bag, and to have an inner face made from a polyethylene type resin or polypropylene type resin of a different kind from the material forming the inner layers of the bag.  
     
     
         5 . The packaging bag with zipper according to  claim 1 , wherein the inner faces of both zipper tapes are made from a polyethylene type resin or polypropylene type resin, and a hot melt type adhesive resin section is provided on the inner face of one of the zipper tapes, at least in a bonding section formed by heat sealing below the engaging section of the zipper tapes.  
     
     
         6 . The packaging bag with zipper according to  claim 1 , wherein a hot melt type adhesive resin section that is to be bonded to the inner layer of the bag, is provided in at least the lower end portion of the outer face of the zipper tape made from a polyethylene type resin or a polypropylene type resin.  
     
     
         7 . The packaging bag with zipper according to  claim 1 , wherein both zipper tapes are made from a resin containing a material comprising a random mixture of a straight-chain low-density polyethylene type resin and a polybutene-1 resin.  
     
     
         8 . The packaging bag with zipper according to  claim 1 , wherein a resin section containing a material comprising a random mixture of a straight-chain low-density polyethylene type resin and a polybutene-1 resin is provided on the inner faces of both zipper tapes, at least in a bonding section formed by heat sealing below the engaging section of the zipper tapes.  
     
     
         9 . The packaging bag with zipper according to  claim 1 , wherein the male zipper tape and the female zipper tape are respectively coloured with mutually different colours.