A Hermetic, Insecticidal Food Storage Bag, Use of It and a Method for Its Production

Abstract

A crop storage bag ( 1 ) made is of a high-strength textile ( 7 ) material which is extrusion-coated or laminated with a multilayer film ( 8 ) that comprises an insecticidal layer ( 9 ) in addition to a hermetic layer ( 10 ) which prevents oxygen from entering the bag. This oxygen barrier suffocates the insects inside the bag, and the insecticide kills insects that try to bore through the bag.

1 . A method for producing a hermetic insecticidal crop storage textile bag ( 1 ), the bag comprising an inner side facing an inner volume and an opposite outer side facing the environment, wherein the method comprises providing the bag ( 1 ) with a polymer multilayer film ( 8 ,  18 ) only on the outer side; wherein the multilayer film ( 8 ) comprises an insecticidal polymer layer ( 9 ) in which an insecticide is melt-incorporated for preventing intrusion of insects into the bag ( 1 ) by the insecticidal polymer layer ( 9 ); wherein the method comprises including at least one oxygen barrier polymer layer ( 10 ) in the multilayer film ( 8 ,  18 ) for providing an Oxygen Transmission Rate, OTR, through the multilayer film ( 8 ) sufficiently low for preventing breeding or killing potential insects inside the bag ( 1 ) when the bag ( 1 ) is in closed condition. 
     
     
         2 . A method according to  claim 1 , wherein the method comprises providing the multilayer film with an OTR less than 300 ccm/m2/day. 
     
     
         3 . A method according to  claim 1 , wherein the method comprises providing a sheet of textile ( 7 ) for the bag and either extrusion-coating a multilayer stream ( 8 ′) of molten polymer onto the textile ( 7 ) and solidifying the stream into the multilayer film ( 8 ) or laminating the multilayer film ( 18 ) onto the textile. 
     
     
         4 . A method according to  claim 2 , wherein the method comprises providing the sheet of textile as an endless textile ( 7 ) web, flattening the textile ( 7 ) web into a flat two-layer textile web ( 15 ) with two opposite outer sides, and covering both outer sides with the multilayer film ( 8 ,  18 ) by the lamination or the extrusion-coating; wherein the insecticidal layer ( 9 ) is provided by a first thermoplastic polymer, and the oxygen barrier layer ( 10 ) is provided by a second thermoplastic polymer that is different from the first thermoplastic polymer; wherein the method comprises orienting the multilayer film ( 8 ,  18 ) with the oxygen barrier ( 10 ) between the textile ( 7 ) web and the insecticidal first polymer layer ( 9 ) for protecting the oxygen barrier ( 10 ) by the insecticidal first polymer layer ( 9 ). 
     
     
         5 . A method according to  claim 3 , wherein the method comprises providing the endless textile ( 7 ) web as a seamless tubular textile web and coating the multilayer film ( 8 ,  18 ) onto the web, and then cutting ( 21 ) the web into portions, each portion for one bag, and finally closing one end ( 4 ) of the portion for providing a bag ( 1 ) with a closed seam ( 22 ,  23 ,  24 ) only at the bottom ( 3 ) or finally closing opposite ends of the portion for providing a bag ( 1 ) with a closed seam ( 22 ,  23 ,  24 ) at the bottom ( 3 ) and at the top of the bag ( 1 ) but no seam on a side of the bag ( 1 ) from the bottom to the top. 
     
     
         6 . A method according to  claim 3 , wherein the method comprises providing the multilayer film ( 8 ,  18 ) with a width that is larger than the flattened web ( 15 ) in order for the multilayer films ( 8 ,  18 ) being fused on opposite sides of the web along and outside both edges ( 15 A) of the web for providing a tight sealing along the web. 
     
     
         7 - 10 . (canceled) 
     
     
         11 . A method according to  claim 1 , wherein the method comprises providing the multilayer film ( 8 ) on the textile ( 7 ) as a four-layer structure with an inner bonding layer ( 11 ′) towards the textile ( 7 ) web on one side of the EVOH oxygen barrier layer ( 10 ), and a second bonding layer ( 11 ) on the opposite side of the EVOH for bonding the EVOH to the insecticidal polyethylene or polypropylene first polymer layer ( 9 ). 
     
     
         12 - 13 . (canceled) 
     
     
         14 . A method according to  claim 1 , wherein the coating of the multilayer film ( 8 ) is provided as a lamination process that comprises melting the first and the second polymer in an extruder ( 17 ) and co-extruding the two layers ( 9 ,  10 ) as part of a multilayer stream ( 18 ′), cooling the multilayer stream ( 18 ′) to form a multilayer film ( 18 ) and rolling the multilayer film ( 18 ) onto rollers ( 19 ); at the lamination location, rolling the multilayer film ( 18 ) from the roller and laminating it onto the textile ( 7 ); laminating an additional outer polymer film layer ( 25 ) onto the multilayer film ( 18 ), which comprises a surface print but no insecticide. 
     
     
         15 . (canceled) 
     
     
         16 . A method according to  claim 1 , wherein the method comprises selecting the insecticide for the insecticidal layer among insecticides that are capable of migrating in the first thermoplastic polymer. 
     
     
         17 . (canceled) 
     
     
         18 . A hermetic insecticidal crop storage textile bag ( 1 ) with an inner side facing an inner volume and an opposite outer side facing the environment, wherein the bag ( 1 ) comprises a textile ( 7 ) sheet with an outer side covered with an extrusion-coated or laminated polymer multilayer film ( 8 ,  18 ), the film ( 8 ,  18 ) comprising an insecticidal layer ( 9 ) of a first thermoplastic polymer layer ( 9 ) containing an insecticide for preventing intrusion of insects into the bag by the insecticidal layer; wherein the multilayer film ( 8 ,  18 ) also comprises at least one oxygen barrier layer ( 10 ) made of a second thermoplastic polymer in order for the multilayer film ( 8 ) with the oxygen barrier layer ( 10 ) having an Oxygen Transmission Rate, OTR, sufficiently low for preventing breeding or killing potential insects inside the bag ( 1 ) when the bag ( 1 ) is in closed condition. 
     
     
         19 . A textile bag according to  claim 18 , wherein the OTR is less than 300 ccm/m2/day at atmospheric pressure. 
     
     
         20 - 22 . (canceled) 
     
     
         23 . A textile bag according to  claim 18 , wherein the oxygen barrier layer ( 10 ) is between the textile ( 7 ) web and the insecticidal first polymer layer ( 9 ) for protecting the oxygen barrier layer ( 10 ) by the insecticidal first polymer layer ( 9 ); wherein the insecticidal first polymer has melt-incorporated therein the insecticide. 
     
     
         24 . A textile bag according to  claim 23 , wherein the insecticide is capable of migrating in the first thermoplastic polymer. 
     
     
         25 - 29 . (canceled) 
     
     
         30 . A textile bag according to  claim 18 , wherein the multilayer film ( 8 ) is covered by an additional outer polymer film layer ( 25 ) comprising a surface print but no insecticide. 
     
     
         31 . (canceled) 
     
     
         32 . A textile bag according to  claim 18 , wherein the insecticide is deltamethrin. 
     
     
         33 . (canceled)