Vented plastic bag with filter medium

Abstract

A vented plastic bag is adapted for containing a powdery product. The plastic bag includes a plurality of walls joined together and formed of a flexible plastic material. The walls define a fill opening for receiving the powdery product into the plastic bag. At least one of the bag walls defines a ventilation zone including a plurality of spaced-apart perforations. A filter medium overlies the ventilation zone and covers the plurality of perforations to substantially capture and retain the powdery product within the plastic bag during fill and ventilation.

1 . A vented plastic bag adapted for containing a powdery product, said plastic bag comprising: 
 a plurality of walls joined together and formed of a flexible plastic material, said walls defining a fill opening for receiving the powdery product into said plastic bag;    at least one of said bag walls defining a ventilation zone comprising a plurality of spaced-apart perforations; and    a fibrous filter medium overlying said ventilation zone and covering said plurality of perforations to substantially capture and retain the powdery product within said plastic bag during fill and ventilation.    
   
   
       2 . A vented plastic bag according to  claim 1 , wherein said filter medium comprises a single-ply filter panel.  
   
   
       3 . A vented plastic bag according to  claim 2 , wherein said filter panel is affixed to said plastic bag along welded seams.  
   
   
       4 . A vented plastic bag according to  claim 1 , wherein said filter medium comprises a non-woven material.  
   
   
       5 . A vented plastic bag according to  claim 1 , wherein said filter medium comprises a fibrous material selected from a group consisting of polyester felt, polypropylene microfiber, nylon monofilament, polyethylene, and PTFE.  
   
   
       6 . A vented plastic bag according to  claim 1 , wherein said filter medium has a nominal micron rating of less than 100.  
   
   
       7 . A vented plastic bag according to  claim 6 , wherein the perforations of said ventilation zone have a nominal micron rating greater than 500.  
   
   
       8 . A vented plastic bag according to  claim 1 , wherein said filter medium is positioned to reside between the powdery product and ventilation zone.  
   
   
       9 . A vented plastic bag according to  claim 8 , wherein a product-side surface of said filter medium is glazed to reduce fiber contamination of the powdery product.  
   
   
       10 . A vented plastic bag adapted for containing a powdery product, said plastic bag comprising: 
 a plurality of walls joined together and formed of a flexible plastic material, said walls defining a fill opening for receiving the powdery product into said plastic bag;    at least one of said bag walls defining a ventilation zone comprising a plurality of spaced-apart perforations; and    a filter medium overlying said ventilation zone and covering said plurality of perforations to substantially capture and retain the powdery product within said plastic bag during fill and ventilation, said filter medium defining a random arrangement of variable-size filtration openings.    
   
   
       11 . A vented plastic bag according to  claim 10 , wherein said filter medium comprises a single-ply filter panel.  
   
   
       12 . A vented plastic bag according to  claim 11 , wherein said filter panel is affixed to said plastic bag along welded seams.  
   
   
       13 . A vented plastic bag according to  claim 10 , wherein said filter medium comprises a non-woven material.  
   
   
       14 . A vented plastic bag according to  claim 10 , wherein said filter medium comprises a fibrous material selected from a group consisting of polyester felt, polypropylene microfiber, nylon monofilament, polyethylene, and PTFE.  
   
   
       15 . A vented plastic bag according to  claim 10 , wherein said filter medium has a nominal micron rating of less than 100.  
   
   
       16 . A vented plastic bag according to  claim 15 , wherein the perforations of said ventilation zone have a nominal micron rating greater than 500.  
   
   
       17 . A vented plastic bag according to  claim 10 , wherein said filter medium is positioned to reside between the powdery product and ventilation zone.  
   
   
       18 . A vented plastic bag according to  claim 17 , wherein a product-side surface of said filter medium is glazed to reduce fiber contamination of the powdery product.  
   
   
       19 . A method for filling a plastic bag with a powdery product, said method comprising the steps of: 
 inserting the powdery product into the plastic bag;    venting the plastic bag; and    during ventilation, filtering air exiting the plastic bag using a fibrous filter medium to substantially capture and retain the powdery product within the plastic bag.    
   
   
       20 . A method according to  claim 19 , and comprising venting the plastic bag through a plurality of perforations formed with a wall of the bag.  
   
   
       21 . A method for filling a plastic bag with a powdery product, said method comprising the steps of: 
 inserting the powdery product into the plastic bag;    venting the plastic bag; and    during ventilation, filtering air exiting the plastic bag using a filter medium to substantially capture and retain the powdery product within the plastic bag, the filter medium defining a random arrangement of variable-size filtration openings.    
   
   
       22 . A method according to  claim 21 , and comprising venting the plastic bag through a plurality of perforations formed with a wall of the bag.  
   
   
       23 . A multi-layer packaging composite, comprising: 
 a flexible plastic sheet material comprising a plurality of spaced-apart perforations; and    a fibrous filter medium overlying said sheet material and covering said plurality of perforations.    
   
   
       24 . A packaging composite according to  claim 23 , wherein said filter medium comprises a single-ply filter panel.  
   
   
       25 . A packaging composite according to  claim 24 , wherein said filter panel is affixed to said plastic sheet material along welded seams.  
   
   
       26 . A packaging composite according to  claim 23 , wherein said filter medium comprises a non-woven material.  
   
   
       27 . A packaging composite according to  claim 23 , wherein said filter medium comprises a fibrous material selected from a group consisting of polyester felt, polypropylene microfiber, nylon monofilament, polyethylene, and PTFE.  
   
   
       28 . A packaging composite according to  claim 23 , wherein said filter medium has a nominal micron rating of less than 100.  
   
   
       29 . A packaging composite according to  claim 28 , wherein the perforations of said plastic sheet material have a nominal micron rating greater than 500.  
   
   
       30 . A packaging composite according to  claim 23 , wherein said filter medium comprising an inside surface residing adjacent said plastic sheet material and a glazed outside surface.  
   
   
       31 . A multi-layer packaging composite, comprising: 
 a flexible plastic sheet material comprising a plurality of spaced-apart perforations; and    a filter medium overlying said sheet material and covering said plurality of perforations, said filter medium defining a random arrangement of variable-size filtration openings.    
   
   
       32 . A packaging composite according to  claim 31 , wherein said filter medium comprises a single-ply filter panel.  
   
   
       33 . A packaging composite according to  claim 32 , wherein said filter panel is affixed to said plastic sheet material along welded seams.  
   
   
       34 . A packaging composite according to  claim 31 , wherein said filter medium comprises a non-woven material.  
   
   
       35 . A packaging composite according to  claim 31 , wherein said filter medium comprises a fibrous material selected from a group consisting of polyester felt, polypropylene microfiber, nylon monofilament, polyethylene, and PTFE.  
   
   
       36 . A packaging composite according to  claim 31 , wherein said filter medium has a nominal micron rating of less than 100.  
   
   
       37 . A packaging composite according to  claim 36 , wherein the perforations of said plastic sheet material have a nominal micron rating greater than 500.  
   
   
       38 . A packaging composite according to  claim 31 , wherein said filter medium comprising an inside surface residing adjacent said plastic sheet material and a glazed outside surface.