Process and apparatus for pouch-forming with optimized fill accuracy and headspace

Abstract

This invention discloses a process for forming a pouch having an evacuated headspace containing a flowable material. The process relates to optimizing both, the evacuation of the headspace in the pouch and the accuracy of the flowable material filled in the pouch. Specifically, the present invention employs a process that includes a multiple-step or a continuous compression of the pouch headspace to accomplish the goals. Also disclosed is a vertical form-fill-seal apparatus for forming a pouch containing a flowable material and having an evacuated headspace.

What is claimed: 
     
         1 . A pouch having an evacuated headspace and containing a flowable material, formed according to a process comprising the steps of:
 (A) providing a continuous tube of flexible and sealable film;   (B) supplying the continuous tube with a predetermined amount of flowable material;   (C) evacuating the headspace above said predetermined amount of flowable material;   wherein said evacuation is performed in two steps:   (i) transversely compressing said continuous tube, at a point where said continuous tube comprises the top portion of said predetermined amount of flowable material, wherein said transverse compressing is accomplished by deflating jaws while said pouch is indexing; and   (ii) further transversely compressing said continuous tube with deflating jaws near or at the end of said indexing of said pouch; and   wherein said transvers compressing is accomplished without stopping said pouch for such transverse compressions and wherein an evacuating passage is provided for removing air from said headspace;   (D) reducing headspace in the pouch by evacuation and allowing flowable material to remain in the pouch;   (E) forming an optimized head space and a pouch having the predetermined amount of flowable material;   (F) pinching said continuous tube above a sealing region so as to form a pinched portion of said continuous tube; and   (G) sealing said continuous tube at said sealing region to form a top seal of said pouch containing flowable material and a bottom seal of a next-to-be filled pouch.   
     
     
         2 . The pouch as recited in  claim 1 , containing an oxygen sensitive product. 
     
     
         3 . The pouch as recited in  claim 1 , wherein the pouch comprises an oxygen scavenging material. 
     
     
         4 . The pouch as recited in  claim 1 , wherein the pouch has a volume of between about 1 L and about 12 L. 
     
     
         5 . The pouch as recited in  claim 1 , wherein the pouch has a volume of between about 3 L and about 5 L. 
     
     
         6 . The pouch as recited in  claim 1 , wherein the headspace has a volume equal to or less than about 2 percent by volume of the pouch. 
     
     
         7 . The pouch as recited in  claim 1 , wherein said pouch is prepared from at least one ply. 
     
     
         8 . The pouch as recited in  claim 7 , wherein said at least one ply comprises only one single layer. 
     
     
         9 . The pouch as recited in  claim 8 , wherein said single layer is selected from the group consisting of linear low-density polyethylene comprising butane copolymeric units, linear low-density polyethylene comprising hexene copolymeric units, linear low-density polyethylene comprising octene copolymeric units, and copolymer of ethylene and propylene. 
     
     
         10 . The pouch, as recited in  claim 8 , wherein said single ply comprises polyethylene; the middle layer comprises metallized biaxial polyester; and the inner layer comprises polyethylene. 
     
     
         11 . The pouch as recited in  claim 8 , wherein single ply has an outer layer comprising an EVOH co-extrusion; the middle layer comprises biaxial nylon; and the inner layer comprises polyethylene. 
     
     
         12 . The pouch as recited in  claim 8 , wherein the single layer is polyethylene functionalized with vinyl acetate or polyethylene blended with ethylene vinyl acetate copolymer. 
     
     
         13 . The pouch as recited in  claim 8 , wherein the single layer is selected from the group consisting of polyethylene, polyethylene modified with methacrylic acid, polyethylene modified with methyl acrylate, polyethylene modified with acrylic acid, ionomers partially-neutralized with zinc or sodium ions, and polyethylene modified by reactive extrusion with maleic anhydride. 
     
     
         14 . The pouch as recited in  claim 8 , wherein the single layer comprises
 an outer layer of the single ply comprises material selected from the group consisting of polyethylene, polyethylene modified with methacrylic acid, polyethylene modified with methyl acrylate, polyethylene modified with acrylic acid, ionomers partially-neutralized with zinc or sodium ions, and polyethylene modified by reactive extrusion with maleic anhydride; middle layer comprises biaxial nylon; and   an inner layer, comprises material selected from the group consisting of polyethylene, polyethylene modified with methacrylic acid, polyethylene modified with methyl acrylate, polyethylene modified with acrylic acid, ionomers partially-neutralized with zinc or sodium ions, and polyethylene modified by reactive extrusion with maleic anhydride.   
     
     
         15 . The pouch as recited in  claim 7 , wherein said pouch is prepared from a multiple-ply film. 
     
     
         16 . The pouch as recited in  claim 15 , wherein at least one ply of said multiple-ply film comprises material selected from the group consisting of polyethylene, polyethylene modified with methacrylic acid, polyethylene modified with methyl acrylate, polyethylene modified with acrylic acid, ionomers partially-neutralized with zinc or sodium ions, and polyethylene modified by reactive extrusion with maleic anhydride. 
     
     
         17 . The pouch as recited in  claim 7 , wherein the wall thickness of the pouch is in the range of from about 50 μm to 175 μm. 
     
     
         18 . The pouch as recited in  claim 7 , wherein the wall thickness of the pouch is in the range of from about 75 μm to 150 μm. 
     
     
         19 . The pouch as recited in  claim 7 , wherein the wall thickness of the pouch is in the range of from about 100 μm to 125 μm. 
     
     
         20 . The pouch as recited in  claim 7 , wherein said pouch comprises a fitment. 
     
     
         21 . A package comprising the pouch of  claim 7  inside a secondary container. 
     
     
         22 . The package as recited in  claim 21 , wherein said secondary container is a cardboard box. 
     
     
         23 . A vertical form-fill-seal apparatus for forming a pouch containing a flowable material and having an evacuated headspace, said apparatus comprising:
 (A) a tube-forming section for forming a vertical continuous tube from a roll of film;   (B) a horizontal sealing section for forming a transverse seal across said vertical continuous tube;   (C) a filling station for supplying a predetermined amount of flowable material to said vertical continuous tube;   (D) pinchers for transversely pinching said vertical continuous tube to form a pinched portion of said continuous tube;   (E) an evacuating passage between said pinchers that opens onto said headspace between the predetermined amount of flowable material and the pinched portion; and   (F) a deflating apparatus for evacuating said headspace via the evacuating passage, wherein said deflating apparatus is programmed to actuate in multiple steps or continuously while the continuous film is indexing.   
     
     
         24 . The vertical form fill-seal apparatus as recited in  claim 23 , wherein said deflating apparatus is actuated in an asynchronous manner.